github.com/yaling888/clash@v1.53.0/component/ebpf/bpf/bpf_helper_defs.h (about)

     1  /* This is auto-generated file. See bpf_doc.py for details. */
     2  
     3  /* Forward declarations of BPF structs */
     4  struct bpf_fib_lookup;
     5  struct bpf_sk_lookup;
     6  struct bpf_perf_event_data;
     7  struct bpf_perf_event_value;
     8  struct bpf_pidns_info;
     9  struct bpf_redir_neigh;
    10  struct bpf_sock;
    11  struct bpf_sock_addr;
    12  struct bpf_sock_ops;
    13  struct bpf_sock_tuple;
    14  struct bpf_spin_lock;
    15  struct bpf_sysctl;
    16  struct bpf_tcp_sock;
    17  struct bpf_tunnel_key;
    18  struct bpf_xfrm_state;
    19  struct linux_binprm;
    20  struct pt_regs;
    21  struct sk_reuseport_md;
    22  struct sockaddr;
    23  struct tcphdr;
    24  struct seq_file;
    25  struct tcp6_sock;
    26  struct tcp_sock;
    27  struct tcp_timewait_sock;
    28  struct tcp_request_sock;
    29  struct udp6_sock;
    30  struct unix_sock;
    31  struct task_struct;
    32  struct __sk_buff;
    33  struct sk_msg_md;
    34  struct xdp_md;
    35  struct path;
    36  struct btf_ptr;
    37  struct inode;
    38  struct socket;
    39  struct file;
    40  struct bpf_timer;
    41  
    42  /*
    43   * bpf_map_lookup_elem
    44   *
    45   * 	Perform a lookup in *map* for an entry associated to *key*.
    46   *
    47   * Returns
    48   * 	Map value associated to *key*, or **NULL** if no entry was
    49   * 	found.
    50   */
    51  static void *(*bpf_map_lookup_elem)(void *map, const void *key) = (void *) 1;
    52  
    53  /*
    54   * bpf_map_update_elem
    55   *
    56   * 	Add or update the value of the entry associated to *key* in
    57   * 	*map* with *value*. *flags* is one of:
    58   *
    59   * 	**BPF_NOEXIST**
    60   * 		The entry for *key* must not exist in the map.
    61   * 	**BPF_EXIST**
    62   * 		The entry for *key* must already exist in the map.
    63   * 	**BPF_ANY**
    64   * 		No condition on the existence of the entry for *key*.
    65   *
    66   * 	Flag value **BPF_NOEXIST** cannot be used for maps of types
    67   * 	**BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY**  (all
    68   * 	elements always exist), the helper would return an error.
    69   *
    70   * Returns
    71   * 	0 on success, or a negative error in case of failure.
    72   */
    73  static long (*bpf_map_update_elem)(void *map, const void *key, const void *value, __u64 flags) = (void *) 2;
    74  
    75  /*
    76   * bpf_map_delete_elem
    77   *
    78   * 	Delete entry with *key* from *map*.
    79   *
    80   * Returns
    81   * 	0 on success, or a negative error in case of failure.
    82   */
    83  static long (*bpf_map_delete_elem)(void *map, const void *key) = (void *) 3;
    84  
    85  /*
    86   * bpf_probe_read
    87   *
    88   * 	For tracing programs, safely attempt to read *size* bytes from
    89   * 	kernel space address *unsafe_ptr* and store the data in *dst*.
    90   *
    91   * 	Generally, use **bpf_probe_read_user**\ () or
    92   * 	**bpf_probe_read_kernel**\ () instead.
    93   *
    94   * Returns
    95   * 	0 on success, or a negative error in case of failure.
    96   */
    97  static long (*bpf_probe_read)(void *dst, __u32 size, const void *unsafe_ptr) = (void *) 4;
    98  
    99  /*
   100   * bpf_ktime_get_ns
   101   *
   102   * 	Return the time elapsed since system boot, in nanoseconds.
   103   * 	Does not include time the system was suspended.
   104   * 	See: **clock_gettime**\ (**CLOCK_MONOTONIC**)
   105   *
   106   * Returns
   107   * 	Current *ktime*.
   108   */
   109  static __u64 (*bpf_ktime_get_ns)(void) = (void *) 5;
   110  
   111  /*
   112   * bpf_trace_printk
   113   *
   114   * 	This helper is a "printk()-like" facility for debugging. It
   115   * 	prints a message defined by format *fmt* (of size *fmt_size*)
   116   * 	to file *\/sys/kernel/debug/tracing/trace* from DebugFS, if
   117   * 	available. It can take up to three additional **u64**
   118   * 	arguments (as an eBPF helpers, the total number of arguments is
   119   * 	limited to five).
   120   *
   121   * 	Each time the helper is called, it appends a line to the trace.
   122   * 	Lines are discarded while *\/sys/kernel/debug/tracing/trace* is
   123   * 	open, use *\/sys/kernel/debug/tracing/trace_pipe* to avoid this.
   124   * 	The format of the trace is customizable, and the exact output
   125   * 	one will get depends on the options set in
   126   * 	*\/sys/kernel/debug/tracing/trace_options* (see also the
   127   * 	*README* file under the same directory). However, it usually
   128   * 	defaults to something like:
   129   *
   130   * 	::
   131   *
   132   * 		telnet-470   [001] .N.. 419421.045894: 0x00000001: <formatted msg>
   133   *
   134   * 	In the above:
   135   *
   136   * 		* ``telnet`` is the name of the current task.
   137   * 		* ``470`` is the PID of the current task.
   138   * 		* ``001`` is the CPU number on which the task is
   139   * 		  running.
   140   * 		* In ``.N..``, each character refers to a set of
   141   * 		  options (whether irqs are enabled, scheduling
   142   * 		  options, whether hard/softirqs are running, level of
   143   * 		  preempt_disabled respectively). **N** means that
   144   * 		  **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED**
   145   * 		  are set.
   146   * 		* ``419421.045894`` is a timestamp.
   147   * 		* ``0x00000001`` is a fake value used by BPF for the
   148   * 		  instruction pointer register.
   149   * 		* ``<formatted msg>`` is the message formatted with
   150   * 		  *fmt*.
   151   *
   152   * 	The conversion specifiers supported by *fmt* are similar, but
   153   * 	more limited than for printk(). They are **%d**, **%i**,
   154   * 	**%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**,
   155   * 	**%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size
   156   * 	of field, padding with zeroes, etc.) is available, and the
   157   * 	helper will return **-EINVAL** (but print nothing) if it
   158   * 	encounters an unknown specifier.
   159   *
   160   * 	Also, note that **bpf_trace_printk**\ () is slow, and should
   161   * 	only be used for debugging purposes. For this reason, a notice
   162   * 	block (spanning several lines) is printed to kernel logs and
   163   * 	states that the helper should not be used "for production use"
   164   * 	the first time this helper is used (or more precisely, when
   165   * 	**trace_printk**\ () buffers are allocated). For passing values
   166   * 	to user space, perf events should be preferred.
   167   *
   168   * Returns
   169   * 	The number of bytes written to the buffer, or a negative error
   170   * 	in case of failure.
   171   */
   172  static long (*bpf_trace_printk)(const char *fmt, __u32 fmt_size, ...) = (void *) 6;
   173  
   174  /*
   175   * bpf_get_prandom_u32
   176   *
   177   * 	Get a pseudo-random number.
   178   *
   179   * 	From a security point of view, this helper uses its own
   180   * 	pseudo-random internal state, and cannot be used to infer the
   181   * 	seed of other random functions in the kernel. However, it is
   182   * 	essential to note that the generator used by the helper is not
   183   * 	cryptographically secure.
   184   *
   185   * Returns
   186   * 	A random 32-bit unsigned value.
   187   */
   188  static __u32 (*bpf_get_prandom_u32)(void) = (void *) 7;
   189  
   190  /*
   191   * bpf_get_smp_processor_id
   192   *
   193   * 	Get the SMP (symmetric multiprocessing) processor id. Note that
   194   * 	all programs run with migration disabled, which means that the
   195   * 	SMP processor id is stable during all the execution of the
   196   * 	program.
   197   *
   198   * Returns
   199   * 	The SMP id of the processor running the program.
   200   */
   201  static __u32 (*bpf_get_smp_processor_id)(void) = (void *) 8;
   202  
   203  /*
   204   * bpf_skb_store_bytes
   205   *
   206   * 	Store *len* bytes from address *from* into the packet
   207   * 	associated to *skb*, at *offset*. *flags* are a combination of
   208   * 	**BPF_F_RECOMPUTE_CSUM** (automatically recompute the
   209   * 	checksum for the packet after storing the bytes) and
   210   * 	**BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\
   211   * 	**->swhash** and *skb*\ **->l4hash** to 0).
   212   *
   213   * 	A call to this helper is susceptible to change the underlying
   214   * 	packet buffer. Therefore, at load time, all checks on pointers
   215   * 	previously done by the verifier are invalidated and must be
   216   * 	performed again, if the helper is used in combination with
   217   * 	direct packet access.
   218   *
   219   * Returns
   220   * 	0 on success, or a negative error in case of failure.
   221   */
   222  static long (*bpf_skb_store_bytes)(struct __sk_buff *skb, __u32 offset, const void *from, __u32 len, __u64 flags) = (void *) 9;
   223  
   224  /*
   225   * bpf_l3_csum_replace
   226   *
   227   * 	Recompute the layer 3 (e.g. IP) checksum for the packet
   228   * 	associated to *skb*. Computation is incremental, so the helper
   229   * 	must know the former value of the header field that was
   230   * 	modified (*from*), the new value of this field (*to*), and the
   231   * 	number of bytes (2 or 4) for this field, stored in *size*.
   232   * 	Alternatively, it is possible to store the difference between
   233   * 	the previous and the new values of the header field in *to*, by
   234   * 	setting *from* and *size* to 0. For both methods, *offset*
   235   * 	indicates the location of the IP checksum within the packet.
   236   *
   237   * 	This helper works in combination with **bpf_csum_diff**\ (),
   238   * 	which does not update the checksum in-place, but offers more
   239   * 	flexibility and can handle sizes larger than 2 or 4 for the
   240   * 	checksum to update.
   241   *
   242   * 	A call to this helper is susceptible to change the underlying
   243   * 	packet buffer. Therefore, at load time, all checks on pointers
   244   * 	previously done by the verifier are invalidated and must be
   245   * 	performed again, if the helper is used in combination with
   246   * 	direct packet access.
   247   *
   248   * Returns
   249   * 	0 on success, or a negative error in case of failure.
   250   */
   251  static long (*bpf_l3_csum_replace)(struct __sk_buff *skb, __u32 offset, __u64 from, __u64 to, __u64 size) = (void *) 10;
   252  
   253  /*
   254   * bpf_l4_csum_replace
   255   *
   256   * 	Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
   257   * 	packet associated to *skb*. Computation is incremental, so the
   258   * 	helper must know the former value of the header field that was
   259   * 	modified (*from*), the new value of this field (*to*), and the
   260   * 	number of bytes (2 or 4) for this field, stored on the lowest
   261   * 	four bits of *flags*. Alternatively, it is possible to store
   262   * 	the difference between the previous and the new values of the
   263   * 	header field in *to*, by setting *from* and the four lowest
   264   * 	bits of *flags* to 0. For both methods, *offset* indicates the
   265   * 	location of the IP checksum within the packet. In addition to
   266   * 	the size of the field, *flags* can be added (bitwise OR) actual
   267   * 	flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left
   268   * 	untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and
   269   * 	for updates resulting in a null checksum the value is set to
   270   * 	**CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates
   271   * 	the checksum is to be computed against a pseudo-header.
   272   *
   273   * 	This helper works in combination with **bpf_csum_diff**\ (),
   274   * 	which does not update the checksum in-place, but offers more
   275   * 	flexibility and can handle sizes larger than 2 or 4 for the
   276   * 	checksum to update.
   277   *
   278   * 	A call to this helper is susceptible to change the underlying
   279   * 	packet buffer. Therefore, at load time, all checks on pointers
   280   * 	previously done by the verifier are invalidated and must be
   281   * 	performed again, if the helper is used in combination with
   282   * 	direct packet access.
   283   *
   284   * Returns
   285   * 	0 on success, or a negative error in case of failure.
   286   */
   287  static long (*bpf_l4_csum_replace)(struct __sk_buff *skb, __u32 offset, __u64 from, __u64 to, __u64 flags) = (void *) 11;
   288  
   289  /*
   290   * bpf_tail_call
   291   *
   292   * 	This special helper is used to trigger a "tail call", or in
   293   * 	other words, to jump into another eBPF program. The same stack
   294   * 	frame is used (but values on stack and in registers for the
   295   * 	caller are not accessible to the callee). This mechanism allows
   296   * 	for program chaining, either for raising the maximum number of
   297   * 	available eBPF instructions, or to execute given programs in
   298   * 	conditional blocks. For security reasons, there is an upper
   299   * 	limit to the number of successive tail calls that can be
   300   * 	performed.
   301   *
   302   * 	Upon call of this helper, the program attempts to jump into a
   303   * 	program referenced at index *index* in *prog_array_map*, a
   304   * 	special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes
   305   * 	*ctx*, a pointer to the context.
   306   *
   307   * 	If the call succeeds, the kernel immediately runs the first
   308   * 	instruction of the new program. This is not a function call,
   309   * 	and it never returns to the previous program. If the call
   310   * 	fails, then the helper has no effect, and the caller continues
   311   * 	to run its subsequent instructions. A call can fail if the
   312   * 	destination program for the jump does not exist (i.e. *index*
   313   * 	is superior to the number of entries in *prog_array_map*), or
   314   * 	if the maximum number of tail calls has been reached for this
   315   * 	chain of programs. This limit is defined in the kernel by the
   316   * 	macro **MAX_TAIL_CALL_CNT** (not accessible to user space),
   317   * 	which is currently set to 33.
   318   *
   319   * Returns
   320   * 	0 on success, or a negative error in case of failure.
   321   */
   322  static long (*bpf_tail_call)(void *ctx, void *prog_array_map, __u32 index) = (void *) 12;
   323  
   324  /*
   325   * bpf_clone_redirect
   326   *
   327   * 	Clone and redirect the packet associated to *skb* to another
   328   * 	net device of index *ifindex*. Both ingress and egress
   329   * 	interfaces can be used for redirection. The **BPF_F_INGRESS**
   330   * 	value in *flags* is used to make the distinction (ingress path
   331   * 	is selected if the flag is present, egress path otherwise).
   332   * 	This is the only flag supported for now.
   333   *
   334   * 	In comparison with **bpf_redirect**\ () helper,
   335   * 	**bpf_clone_redirect**\ () has the associated cost of
   336   * 	duplicating the packet buffer, but this can be executed out of
   337   * 	the eBPF program. Conversely, **bpf_redirect**\ () is more
   338   * 	efficient, but it is handled through an action code where the
   339   * 	redirection happens only after the eBPF program has returned.
   340   *
   341   * 	A call to this helper is susceptible to change the underlying
   342   * 	packet buffer. Therefore, at load time, all checks on pointers
   343   * 	previously done by the verifier are invalidated and must be
   344   * 	performed again, if the helper is used in combination with
   345   * 	direct packet access.
   346   *
   347   * Returns
   348   * 	0 on success, or a negative error in case of failure.
   349   */
   350  static long (*bpf_clone_redirect)(struct __sk_buff *skb, __u32 ifindex, __u64 flags) = (void *) 13;
   351  
   352  /*
   353   * bpf_get_current_pid_tgid
   354   *
   355   *
   356   * Returns
   357   * 	A 64-bit integer containing the current tgid and pid, and
   358   * 	created as such:
   359   * 	*current_task*\ **->tgid << 32 \|**
   360   * 	*current_task*\ **->pid**.
   361   */
   362  static __u64 (*bpf_get_current_pid_tgid)(void) = (void *) 14;
   363  
   364  /*
   365   * bpf_get_current_uid_gid
   366   *
   367   *
   368   * Returns
   369   * 	A 64-bit integer containing the current GID and UID, and
   370   * 	created as such: *current_gid* **<< 32 \|** *current_uid*.
   371   */
   372  static __u64 (*bpf_get_current_uid_gid)(void) = (void *) 15;
   373  
   374  /*
   375   * bpf_get_current_comm
   376   *
   377   * 	Copy the **comm** attribute of the current task into *buf* of
   378   * 	*size_of_buf*. The **comm** attribute contains the name of
   379   * 	the executable (excluding the path) for the current task. The
   380   * 	*size_of_buf* must be strictly positive. On success, the
   381   * 	helper makes sure that the *buf* is NUL-terminated. On failure,
   382   * 	it is filled with zeroes.
   383   *
   384   * Returns
   385   * 	0 on success, or a negative error in case of failure.
   386   */
   387  static long (*bpf_get_current_comm)(void *buf, __u32 size_of_buf) = (void *) 16;
   388  
   389  /*
   390   * bpf_get_cgroup_classid
   391   *
   392   * 	Retrieve the classid for the current task, i.e. for the net_cls
   393   * 	cgroup to which *skb* belongs.
   394   *
   395   * 	This helper can be used on TC egress path, but not on ingress.
   396   *
   397   * 	The net_cls cgroup provides an interface to tag network packets
   398   * 	based on a user-provided identifier for all traffic coming from
   399   * 	the tasks belonging to the related cgroup. See also the related
   400   * 	kernel documentation, available from the Linux sources in file
   401   * 	*Documentation/admin-guide/cgroup-v1/net_cls.rst*.
   402   *
   403   * 	The Linux kernel has two versions for cgroups: there are
   404   * 	cgroups v1 and cgroups v2. Both are available to users, who can
   405   * 	use a mixture of them, but note that the net_cls cgroup is for
   406   * 	cgroup v1 only. This makes it incompatible with BPF programs
   407   * 	run on cgroups, which is a cgroup-v2-only feature (a socket can
   408   * 	only hold data for one version of cgroups at a time).
   409   *
   410   * 	This helper is only available is the kernel was compiled with
   411   * 	the **CONFIG_CGROUP_NET_CLASSID** configuration option set to
   412   * 	"**y**" or to "**m**".
   413   *
   414   * Returns
   415   * 	The classid, or 0 for the default unconfigured classid.
   416   */
   417  static __u32 (*bpf_get_cgroup_classid)(struct __sk_buff *skb) = (void *) 17;
   418  
   419  /*
   420   * bpf_skb_vlan_push
   421   *
   422   * 	Push a *vlan_tci* (VLAN tag control information) of protocol
   423   * 	*vlan_proto* to the packet associated to *skb*, then update
   424   * 	the checksum. Note that if *vlan_proto* is different from
   425   * 	**ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to
   426   * 	be **ETH_P_8021Q**.
   427   *
   428   * 	A call to this helper is susceptible to change the underlying
   429   * 	packet buffer. Therefore, at load time, all checks on pointers
   430   * 	previously done by the verifier are invalidated and must be
   431   * 	performed again, if the helper is used in combination with
   432   * 	direct packet access.
   433   *
   434   * Returns
   435   * 	0 on success, or a negative error in case of failure.
   436   */
   437  static long (*bpf_skb_vlan_push)(struct __sk_buff *skb, __be16 vlan_proto, __u16 vlan_tci) = (void *) 18;
   438  
   439  /*
   440   * bpf_skb_vlan_pop
   441   *
   442   * 	Pop a VLAN header from the packet associated to *skb*.
   443   *
   444   * 	A call to this helper is susceptible to change the underlying
   445   * 	packet buffer. Therefore, at load time, all checks on pointers
   446   * 	previously done by the verifier are invalidated and must be
   447   * 	performed again, if the helper is used in combination with
   448   * 	direct packet access.
   449   *
   450   * Returns
   451   * 	0 on success, or a negative error in case of failure.
   452   */
   453  static long (*bpf_skb_vlan_pop)(struct __sk_buff *skb) = (void *) 19;
   454  
   455  /*
   456   * bpf_skb_get_tunnel_key
   457   *
   458   * 	Get tunnel metadata. This helper takes a pointer *key* to an
   459   * 	empty **struct bpf_tunnel_key** of **size**, that will be
   460   * 	filled with tunnel metadata for the packet associated to *skb*.
   461   * 	The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which
   462   * 	indicates that the tunnel is based on IPv6 protocol instead of
   463   * 	IPv4.
   464   *
   465   * 	The **struct bpf_tunnel_key** is an object that generalizes the
   466   * 	principal parameters used by various tunneling protocols into a
   467   * 	single struct. This way, it can be used to easily make a
   468   * 	decision based on the contents of the encapsulation header,
   469   * 	"summarized" in this struct. In particular, it holds the IP
   470   * 	address of the remote end (IPv4 or IPv6, depending on the case)
   471   * 	in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also,
   472   * 	this struct exposes the *key*\ **->tunnel_id**, which is
   473   * 	generally mapped to a VNI (Virtual Network Identifier), making
   474   * 	it programmable together with the **bpf_skb_set_tunnel_key**\
   475   * 	() helper.
   476   *
   477   * 	Let's imagine that the following code is part of a program
   478   * 	attached to the TC ingress interface, on one end of a GRE
   479   * 	tunnel, and is supposed to filter out all messages coming from
   480   * 	remote ends with IPv4 address other than 10.0.0.1:
   481   *
   482   * 	::
   483   *
   484   * 		int ret;
   485   * 		struct bpf_tunnel_key key = {};
   486   *
   487   * 		ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
   488   * 		if (ret < 0)
   489   * 			return TC_ACT_SHOT;	// drop packet
   490   *
   491   * 		if (key.remote_ipv4 != 0x0a000001)
   492   * 			return TC_ACT_SHOT;	// drop packet
   493   *
   494   * 		return TC_ACT_OK;		// accept packet
   495   *
   496   * 	This interface can also be used with all encapsulation devices
   497   * 	that can operate in "collect metadata" mode: instead of having
   498   * 	one network device per specific configuration, the "collect
   499   * 	metadata" mode only requires a single device where the
   500   * 	configuration can be extracted from this helper.
   501   *
   502   * 	This can be used together with various tunnels such as VXLan,
   503   * 	Geneve, GRE or IP in IP (IPIP).
   504   *
   505   * Returns
   506   * 	0 on success, or a negative error in case of failure.
   507   */
   508  static long (*bpf_skb_get_tunnel_key)(struct __sk_buff *skb, struct bpf_tunnel_key *key, __u32 size, __u64 flags) = (void *) 20;
   509  
   510  /*
   511   * bpf_skb_set_tunnel_key
   512   *
   513   * 	Populate tunnel metadata for packet associated to *skb.* The
   514   * 	tunnel metadata is set to the contents of *key*, of *size*. The
   515   * 	*flags* can be set to a combination of the following values:
   516   *
   517   * 	**BPF_F_TUNINFO_IPV6**
   518   * 		Indicate that the tunnel is based on IPv6 protocol
   519   * 		instead of IPv4.
   520   * 	**BPF_F_ZERO_CSUM_TX**
   521   * 		For IPv4 packets, add a flag to tunnel metadata
   522   * 		indicating that checksum computation should be skipped
   523   * 		and checksum set to zeroes.
   524   * 	**BPF_F_DONT_FRAGMENT**
   525   * 		Add a flag to tunnel metadata indicating that the
   526   * 		packet should not be fragmented.
   527   * 	**BPF_F_SEQ_NUMBER**
   528   * 		Add a flag to tunnel metadata indicating that a
   529   * 		sequence number should be added to tunnel header before
   530   * 		sending the packet. This flag was added for GRE
   531   * 		encapsulation, but might be used with other protocols
   532   * 		as well in the future.
   533   *
   534   * 	Here is a typical usage on the transmit path:
   535   *
   536   * 	::
   537   *
   538   * 		struct bpf_tunnel_key key;
   539   * 		     populate key ...
   540   * 		bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
   541   * 		bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
   542   *
   543   * 	See also the description of the **bpf_skb_get_tunnel_key**\ ()
   544   * 	helper for additional information.
   545   *
   546   * Returns
   547   * 	0 on success, or a negative error in case of failure.
   548   */
   549  static long (*bpf_skb_set_tunnel_key)(struct __sk_buff *skb, struct bpf_tunnel_key *key, __u32 size, __u64 flags) = (void *) 21;
   550  
   551  /*
   552   * bpf_perf_event_read
   553   *
   554   * 	Read the value of a perf event counter. This helper relies on a
   555   * 	*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of
   556   * 	the perf event counter is selected when *map* is updated with
   557   * 	perf event file descriptors. The *map* is an array whose size
   558   * 	is the number of available CPUs, and each cell contains a value
   559   * 	relative to one CPU. The value to retrieve is indicated by
   560   * 	*flags*, that contains the index of the CPU to look up, masked
   561   * 	with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
   562   * 	**BPF_F_CURRENT_CPU** to indicate that the value for the
   563   * 	current CPU should be retrieved.
   564   *
   565   * 	Note that before Linux 4.13, only hardware perf event can be
   566   * 	retrieved.
   567   *
   568   * 	Also, be aware that the newer helper
   569   * 	**bpf_perf_event_read_value**\ () is recommended over
   570   * 	**bpf_perf_event_read**\ () in general. The latter has some ABI
   571   * 	quirks where error and counter value are used as a return code
   572   * 	(which is wrong to do since ranges may overlap). This issue is
   573   * 	fixed with **bpf_perf_event_read_value**\ (), which at the same
   574   * 	time provides more features over the **bpf_perf_event_read**\
   575   * 	() interface. Please refer to the description of
   576   * 	**bpf_perf_event_read_value**\ () for details.
   577   *
   578   * Returns
   579   * 	The value of the perf event counter read from the map, or a
   580   * 	negative error code in case of failure.
   581   */
   582  static __u64 (*bpf_perf_event_read)(void *map, __u64 flags) = (void *) 22;
   583  
   584  /*
   585   * bpf_redirect
   586   *
   587   * 	Redirect the packet to another net device of index *ifindex*.
   588   * 	This helper is somewhat similar to **bpf_clone_redirect**\
   589   * 	(), except that the packet is not cloned, which provides
   590   * 	increased performance.
   591   *
   592   * 	Except for XDP, both ingress and egress interfaces can be used
   593   * 	for redirection. The **BPF_F_INGRESS** value in *flags* is used
   594   * 	to make the distinction (ingress path is selected if the flag
   595   * 	is present, egress path otherwise). Currently, XDP only
   596   * 	supports redirection to the egress interface, and accepts no
   597   * 	flag at all.
   598   *
   599   * 	The same effect can also be attained with the more generic
   600   * 	**bpf_redirect_map**\ (), which uses a BPF map to store the
   601   * 	redirect target instead of providing it directly to the helper.
   602   *
   603   * Returns
   604   * 	For XDP, the helper returns **XDP_REDIRECT** on success or
   605   * 	**XDP_ABORTED** on error. For other program types, the values
   606   * 	are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on
   607   * 	error.
   608   */
   609  static long (*bpf_redirect)(__u32 ifindex, __u64 flags) = (void *) 23;
   610  
   611  /*
   612   * bpf_get_route_realm
   613   *
   614   * 	Retrieve the realm or the route, that is to say the
   615   * 	**tclassid** field of the destination for the *skb*. The
   616   * 	identifier retrieved is a user-provided tag, similar to the
   617   * 	one used with the net_cls cgroup (see description for
   618   * 	**bpf_get_cgroup_classid**\ () helper), but here this tag is
   619   * 	held by a route (a destination entry), not by a task.
   620   *
   621   * 	Retrieving this identifier works with the clsact TC egress hook
   622   * 	(see also **tc-bpf(8)**), or alternatively on conventional
   623   * 	classful egress qdiscs, but not on TC ingress path. In case of
   624   * 	clsact TC egress hook, this has the advantage that, internally,
   625   * 	the destination entry has not been dropped yet in the transmit
   626   * 	path. Therefore, the destination entry does not need to be
   627   * 	artificially held via **netif_keep_dst**\ () for a classful
   628   * 	qdisc until the *skb* is freed.
   629   *
   630   * 	This helper is available only if the kernel was compiled with
   631   * 	**CONFIG_IP_ROUTE_CLASSID** configuration option.
   632   *
   633   * Returns
   634   * 	The realm of the route for the packet associated to *skb*, or 0
   635   * 	if none was found.
   636   */
   637  static __u32 (*bpf_get_route_realm)(struct __sk_buff *skb) = (void *) 24;
   638  
   639  /*
   640   * bpf_perf_event_output
   641   *
   642   * 	Write raw *data* blob into a special BPF perf event held by
   643   * 	*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
   644   * 	event must have the following attributes: **PERF_SAMPLE_RAW**
   645   * 	as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
   646   * 	**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
   647   *
   648   * 	The *flags* are used to indicate the index in *map* for which
   649   * 	the value must be put, masked with **BPF_F_INDEX_MASK**.
   650   * 	Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
   651   * 	to indicate that the index of the current CPU core should be
   652   * 	used.
   653   *
   654   * 	The value to write, of *size*, is passed through eBPF stack and
   655   * 	pointed by *data*.
   656   *
   657   * 	The context of the program *ctx* needs also be passed to the
   658   * 	helper.
   659   *
   660   * 	On user space, a program willing to read the values needs to
   661   * 	call **perf_event_open**\ () on the perf event (either for
   662   * 	one or for all CPUs) and to store the file descriptor into the
   663   * 	*map*. This must be done before the eBPF program can send data
   664   * 	into it. An example is available in file
   665   * 	*samples/bpf/trace_output_user.c* in the Linux kernel source
   666   * 	tree (the eBPF program counterpart is in
   667   * 	*samples/bpf/trace_output_kern.c*).
   668   *
   669   * 	**bpf_perf_event_output**\ () achieves better performance
   670   * 	than **bpf_trace_printk**\ () for sharing data with user
   671   * 	space, and is much better suitable for streaming data from eBPF
   672   * 	programs.
   673   *
   674   * 	Note that this helper is not restricted to tracing use cases
   675   * 	and can be used with programs attached to TC or XDP as well,
   676   * 	where it allows for passing data to user space listeners. Data
   677   * 	can be:
   678   *
   679   * 	* Only custom structs,
   680   * 	* Only the packet payload, or
   681   * 	* A combination of both.
   682   *
   683   * Returns
   684   * 	0 on success, or a negative error in case of failure.
   685   */
   686  static long (*bpf_perf_event_output)(void *ctx, void *map, __u64 flags, void *data, __u64 size) = (void *) 25;
   687  
   688  /*
   689   * bpf_skb_load_bytes
   690   *
   691   * 	This helper was provided as an easy way to load data from a
   692   * 	packet. It can be used to load *len* bytes from *offset* from
   693   * 	the packet associated to *skb*, into the buffer pointed by
   694   * 	*to*.
   695   *
   696   * 	Since Linux 4.7, usage of this helper has mostly been replaced
   697   * 	by "direct packet access", enabling packet data to be
   698   * 	manipulated with *skb*\ **->data** and *skb*\ **->data_end**
   699   * 	pointing respectively to the first byte of packet data and to
   700   * 	the byte after the last byte of packet data. However, it
   701   * 	remains useful if one wishes to read large quantities of data
   702   * 	at once from a packet into the eBPF stack.
   703   *
   704   * Returns
   705   * 	0 on success, or a negative error in case of failure.
   706   */
   707  static long (*bpf_skb_load_bytes)(const void *skb, __u32 offset, void *to, __u32 len) = (void *) 26;
   708  
   709  /*
   710   * bpf_get_stackid
   711   *
   712   * 	Walk a user or a kernel stack and return its id. To achieve
   713   * 	this, the helper needs *ctx*, which is a pointer to the context
   714   * 	on which the tracing program is executed, and a pointer to a
   715   * 	*map* of type **BPF_MAP_TYPE_STACK_TRACE**.
   716   *
   717   * 	The last argument, *flags*, holds the number of stack frames to
   718   * 	skip (from 0 to 255), masked with
   719   * 	**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
   720   * 	a combination of the following flags:
   721   *
   722   * 	**BPF_F_USER_STACK**
   723   * 		Collect a user space stack instead of a kernel stack.
   724   * 	**BPF_F_FAST_STACK_CMP**
   725   * 		Compare stacks by hash only.
   726   * 	**BPF_F_REUSE_STACKID**
   727   * 		If two different stacks hash into the same *stackid*,
   728   * 		discard the old one.
   729   *
   730   * 	The stack id retrieved is a 32 bit long integer handle which
   731   * 	can be further combined with other data (including other stack
   732   * 	ids) and used as a key into maps. This can be useful for
   733   * 	generating a variety of graphs (such as flame graphs or off-cpu
   734   * 	graphs).
   735   *
   736   * 	For walking a stack, this helper is an improvement over
   737   * 	**bpf_probe_read**\ (), which can be used with unrolled loops
   738   * 	but is not efficient and consumes a lot of eBPF instructions.
   739   * 	Instead, **bpf_get_stackid**\ () can collect up to
   740   * 	**PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that
   741   * 	this limit can be controlled with the **sysctl** program, and
   742   * 	that it should be manually increased in order to profile long
   743   * 	user stacks (such as stacks for Java programs). To do so, use:
   744   *
   745   * 	::
   746   *
   747   * 		# sysctl kernel.perf_event_max_stack=<new value>
   748   *
   749   * Returns
   750   * 	The positive or null stack id on success, or a negative error
   751   * 	in case of failure.
   752   */
   753  static long (*bpf_get_stackid)(void *ctx, void *map, __u64 flags) = (void *) 27;
   754  
   755  /*
   756   * bpf_csum_diff
   757   *
   758   * 	Compute a checksum difference, from the raw buffer pointed by
   759   * 	*from*, of length *from_size* (that must be a multiple of 4),
   760   * 	towards the raw buffer pointed by *to*, of size *to_size*
   761   * 	(same remark). An optional *seed* can be added to the value
   762   * 	(this can be cascaded, the seed may come from a previous call
   763   * 	to the helper).
   764   *
   765   * 	This is flexible enough to be used in several ways:
   766   *
   767   * 	* With *from_size* == 0, *to_size* > 0 and *seed* set to
   768   * 	  checksum, it can be used when pushing new data.
   769   * 	* With *from_size* > 0, *to_size* == 0 and *seed* set to
   770   * 	  checksum, it can be used when removing data from a packet.
   771   * 	* With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it
   772   * 	  can be used to compute a diff. Note that *from_size* and
   773   * 	  *to_size* do not need to be equal.
   774   *
   775   * 	This helper can be used in combination with
   776   * 	**bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to
   777   * 	which one can feed in the difference computed with
   778   * 	**bpf_csum_diff**\ ().
   779   *
   780   * Returns
   781   * 	The checksum result, or a negative error code in case of
   782   * 	failure.
   783   */
   784  static __s64 (*bpf_csum_diff)(__be32 *from, __u32 from_size, __be32 *to, __u32 to_size, __wsum seed) = (void *) 28;
   785  
   786  /*
   787   * bpf_skb_get_tunnel_opt
   788   *
   789   * 	Retrieve tunnel options metadata for the packet associated to
   790   * 	*skb*, and store the raw tunnel option data to the buffer *opt*
   791   * 	of *size*.
   792   *
   793   * 	This helper can be used with encapsulation devices that can
   794   * 	operate in "collect metadata" mode (please refer to the related
   795   * 	note in the description of **bpf_skb_get_tunnel_key**\ () for
   796   * 	more details). A particular example where this can be used is
   797   * 	in combination with the Geneve encapsulation protocol, where it
   798   * 	allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper)
   799   * 	and retrieving arbitrary TLVs (Type-Length-Value headers) from
   800   * 	the eBPF program. This allows for full customization of these
   801   * 	headers.
   802   *
   803   * Returns
   804   * 	The size of the option data retrieved.
   805   */
   806  static long (*bpf_skb_get_tunnel_opt)(struct __sk_buff *skb, void *opt, __u32 size) = (void *) 29;
   807  
   808  /*
   809   * bpf_skb_set_tunnel_opt
   810   *
   811   * 	Set tunnel options metadata for the packet associated to *skb*
   812   * 	to the option data contained in the raw buffer *opt* of *size*.
   813   *
   814   * 	See also the description of the **bpf_skb_get_tunnel_opt**\ ()
   815   * 	helper for additional information.
   816   *
   817   * Returns
   818   * 	0 on success, or a negative error in case of failure.
   819   */
   820  static long (*bpf_skb_set_tunnel_opt)(struct __sk_buff *skb, void *opt, __u32 size) = (void *) 30;
   821  
   822  /*
   823   * bpf_skb_change_proto
   824   *
   825   * 	Change the protocol of the *skb* to *proto*. Currently
   826   * 	supported are transition from IPv4 to IPv6, and from IPv6 to
   827   * 	IPv4. The helper takes care of the groundwork for the
   828   * 	transition, including resizing the socket buffer. The eBPF
   829   * 	program is expected to fill the new headers, if any, via
   830   * 	**skb_store_bytes**\ () and to recompute the checksums with
   831   * 	**bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\
   832   * 	(). The main case for this helper is to perform NAT64
   833   * 	operations out of an eBPF program.
   834   *
   835   * 	Internally, the GSO type is marked as dodgy so that headers are
   836   * 	checked and segments are recalculated by the GSO/GRO engine.
   837   * 	The size for GSO target is adapted as well.
   838   *
   839   * 	All values for *flags* are reserved for future usage, and must
   840   * 	be left at zero.
   841   *
   842   * 	A call to this helper is susceptible to change the underlying
   843   * 	packet buffer. Therefore, at load time, all checks on pointers
   844   * 	previously done by the verifier are invalidated and must be
   845   * 	performed again, if the helper is used in combination with
   846   * 	direct packet access.
   847   *
   848   * Returns
   849   * 	0 on success, or a negative error in case of failure.
   850   */
   851  static long (*bpf_skb_change_proto)(struct __sk_buff *skb, __be16 proto, __u64 flags) = (void *) 31;
   852  
   853  /*
   854   * bpf_skb_change_type
   855   *
   856   * 	Change the packet type for the packet associated to *skb*. This
   857   * 	comes down to setting *skb*\ **->pkt_type** to *type*, except
   858   * 	the eBPF program does not have a write access to *skb*\
   859   * 	**->pkt_type** beside this helper. Using a helper here allows
   860   * 	for graceful handling of errors.
   861   *
   862   * 	The major use case is to change incoming *skb*s to
   863   * 	**PACKET_HOST** in a programmatic way instead of having to
   864   * 	recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for
   865   * 	example.
   866   *
   867   * 	Note that *type* only allows certain values. At this time, they
   868   * 	are:
   869   *
   870   * 	**PACKET_HOST**
   871   * 		Packet is for us.
   872   * 	**PACKET_BROADCAST**
   873   * 		Send packet to all.
   874   * 	**PACKET_MULTICAST**
   875   * 		Send packet to group.
   876   * 	**PACKET_OTHERHOST**
   877   * 		Send packet to someone else.
   878   *
   879   * Returns
   880   * 	0 on success, or a negative error in case of failure.
   881   */
   882  static long (*bpf_skb_change_type)(struct __sk_buff *skb, __u32 type) = (void *) 32;
   883  
   884  /*
   885   * bpf_skb_under_cgroup
   886   *
   887   * 	Check whether *skb* is a descendant of the cgroup2 held by
   888   * 	*map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
   889   *
   890   * Returns
   891   * 	The return value depends on the result of the test, and can be:
   892   *
   893   * 	* 0, if the *skb* failed the cgroup2 descendant test.
   894   * 	* 1, if the *skb* succeeded the cgroup2 descendant test.
   895   * 	* A negative error code, if an error occurred.
   896   */
   897  static long (*bpf_skb_under_cgroup)(struct __sk_buff *skb, void *map, __u32 index) = (void *) 33;
   898  
   899  /*
   900   * bpf_get_hash_recalc
   901   *
   902   * 	Retrieve the hash of the packet, *skb*\ **->hash**. If it is
   903   * 	not set, in particular if the hash was cleared due to mangling,
   904   * 	recompute this hash. Later accesses to the hash can be done
   905   * 	directly with *skb*\ **->hash**.
   906   *
   907   * 	Calling **bpf_set_hash_invalid**\ (), changing a packet
   908   * 	prototype with **bpf_skb_change_proto**\ (), or calling
   909   * 	**bpf_skb_store_bytes**\ () with the
   910   * 	**BPF_F_INVALIDATE_HASH** are actions susceptible to clear
   911   * 	the hash and to trigger a new computation for the next call to
   912   * 	**bpf_get_hash_recalc**\ ().
   913   *
   914   * Returns
   915   * 	The 32-bit hash.
   916   */
   917  static __u32 (*bpf_get_hash_recalc)(struct __sk_buff *skb) = (void *) 34;
   918  
   919  /*
   920   * bpf_get_current_task
   921   *
   922   *
   923   * Returns
   924   * 	A pointer to the current task struct.
   925   */
   926  static __u64 (*bpf_get_current_task)(void) = (void *) 35;
   927  
   928  /*
   929   * bpf_probe_write_user
   930   *
   931   * 	Attempt in a safe way to write *len* bytes from the buffer
   932   * 	*src* to *dst* in memory. It only works for threads that are in
   933   * 	user context, and *dst* must be a valid user space address.
   934   *
   935   * 	This helper should not be used to implement any kind of
   936   * 	security mechanism because of TOC-TOU attacks, but rather to
   937   * 	debug, divert, and manipulate execution of semi-cooperative
   938   * 	processes.
   939   *
   940   * 	Keep in mind that this feature is meant for experiments, and it
   941   * 	has a risk of crashing the system and running programs.
   942   * 	Therefore, when an eBPF program using this helper is attached,
   943   * 	a warning including PID and process name is printed to kernel
   944   * 	logs.
   945   *
   946   * Returns
   947   * 	0 on success, or a negative error in case of failure.
   948   */
   949  static long (*bpf_probe_write_user)(void *dst, const void *src, __u32 len) = (void *) 36;
   950  
   951  /*
   952   * bpf_current_task_under_cgroup
   953   *
   954   * 	Check whether the probe is being run is the context of a given
   955   * 	subset of the cgroup2 hierarchy. The cgroup2 to test is held by
   956   * 	*map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
   957   *
   958   * Returns
   959   * 	The return value depends on the result of the test, and can be:
   960   *
   961   * 	* 0, if current task belongs to the cgroup2.
   962   * 	* 1, if current task does not belong to the cgroup2.
   963   * 	* A negative error code, if an error occurred.
   964   */
   965  static long (*bpf_current_task_under_cgroup)(void *map, __u32 index) = (void *) 37;
   966  
   967  /*
   968   * bpf_skb_change_tail
   969   *
   970   * 	Resize (trim or grow) the packet associated to *skb* to the
   971   * 	new *len*. The *flags* are reserved for future usage, and must
   972   * 	be left at zero.
   973   *
   974   * 	The basic idea is that the helper performs the needed work to
   975   * 	change the size of the packet, then the eBPF program rewrites
   976   * 	the rest via helpers like **bpf_skb_store_bytes**\ (),
   977   * 	**bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ ()
   978   * 	and others. This helper is a slow path utility intended for
   979   * 	replies with control messages. And because it is targeted for
   980   * 	slow path, the helper itself can afford to be slow: it
   981   * 	implicitly linearizes, unclones and drops offloads from the
   982   * 	*skb*.
   983   *
   984   * 	A call to this helper is susceptible to change the underlying
   985   * 	packet buffer. Therefore, at load time, all checks on pointers
   986   * 	previously done by the verifier are invalidated and must be
   987   * 	performed again, if the helper is used in combination with
   988   * 	direct packet access.
   989   *
   990   * Returns
   991   * 	0 on success, or a negative error in case of failure.
   992   */
   993  static long (*bpf_skb_change_tail)(struct __sk_buff *skb, __u32 len, __u64 flags) = (void *) 38;
   994  
   995  /*
   996   * bpf_skb_pull_data
   997   *
   998   * 	Pull in non-linear data in case the *skb* is non-linear and not
   999   * 	all of *len* are part of the linear section. Make *len* bytes
  1000   * 	from *skb* readable and writable. If a zero value is passed for
  1001   * 	*len*, then the whole length of the *skb* is pulled.
  1002   *
  1003   * 	This helper is only needed for reading and writing with direct
  1004   * 	packet access.
  1005   *
  1006   * 	For direct packet access, testing that offsets to access
  1007   * 	are within packet boundaries (test on *skb*\ **->data_end**) is
  1008   * 	susceptible to fail if offsets are invalid, or if the requested
  1009   * 	data is in non-linear parts of the *skb*. On failure the
  1010   * 	program can just bail out, or in the case of a non-linear
  1011   * 	buffer, use a helper to make the data available. The
  1012   * 	**bpf_skb_load_bytes**\ () helper is a first solution to access
  1013   * 	the data. Another one consists in using **bpf_skb_pull_data**
  1014   * 	to pull in once the non-linear parts, then retesting and
  1015   * 	eventually access the data.
  1016   *
  1017   * 	At the same time, this also makes sure the *skb* is uncloned,
  1018   * 	which is a necessary condition for direct write. As this needs
  1019   * 	to be an invariant for the write part only, the verifier
  1020   * 	detects writes and adds a prologue that is calling
  1021   * 	**bpf_skb_pull_data()** to effectively unclone the *skb* from
  1022   * 	the very beginning in case it is indeed cloned.
  1023   *
  1024   * 	A call to this helper is susceptible to change the underlying
  1025   * 	packet buffer. Therefore, at load time, all checks on pointers
  1026   * 	previously done by the verifier are invalidated and must be
  1027   * 	performed again, if the helper is used in combination with
  1028   * 	direct packet access.
  1029   *
  1030   * Returns
  1031   * 	0 on success, or a negative error in case of failure.
  1032   */
  1033  static long (*bpf_skb_pull_data)(struct __sk_buff *skb, __u32 len) = (void *) 39;
  1034  
  1035  /*
  1036   * bpf_csum_update
  1037   *
  1038   * 	Add the checksum *csum* into *skb*\ **->csum** in case the
  1039   * 	driver has supplied a checksum for the entire packet into that
  1040   * 	field. Return an error otherwise. This helper is intended to be
  1041   * 	used in combination with **bpf_csum_diff**\ (), in particular
  1042   * 	when the checksum needs to be updated after data has been
  1043   * 	written into the packet through direct packet access.
  1044   *
  1045   * Returns
  1046   * 	The checksum on success, or a negative error code in case of
  1047   * 	failure.
  1048   */
  1049  static __s64 (*bpf_csum_update)(struct __sk_buff *skb, __wsum csum) = (void *) 40;
  1050  
  1051  /*
  1052   * bpf_set_hash_invalid
  1053   *
  1054   * 	Invalidate the current *skb*\ **->hash**. It can be used after
  1055   * 	mangling on headers through direct packet access, in order to
  1056   * 	indicate that the hash is outdated and to trigger a
  1057   * 	recalculation the next time the kernel tries to access this
  1058   * 	hash or when the **bpf_get_hash_recalc**\ () helper is called.
  1059   *
  1060   */
  1061  static void (*bpf_set_hash_invalid)(struct __sk_buff *skb) = (void *) 41;
  1062  
  1063  /*
  1064   * bpf_get_numa_node_id
  1065   *
  1066   * 	Return the id of the current NUMA node. The primary use case
  1067   * 	for this helper is the selection of sockets for the local NUMA
  1068   * 	node, when the program is attached to sockets using the
  1069   * 	**SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**),
  1070   * 	but the helper is also available to other eBPF program types,
  1071   * 	similarly to **bpf_get_smp_processor_id**\ ().
  1072   *
  1073   * Returns
  1074   * 	The id of current NUMA node.
  1075   */
  1076  static long (*bpf_get_numa_node_id)(void) = (void *) 42;
  1077  
  1078  /*
  1079   * bpf_skb_change_head
  1080   *
  1081   * 	Grows headroom of packet associated to *skb* and adjusts the
  1082   * 	offset of the MAC header accordingly, adding *len* bytes of
  1083   * 	space. It automatically extends and reallocates memory as
  1084   * 	required.
  1085   *
  1086   * 	This helper can be used on a layer 3 *skb* to push a MAC header
  1087   * 	for redirection into a layer 2 device.
  1088   *
  1089   * 	All values for *flags* are reserved for future usage, and must
  1090   * 	be left at zero.
  1091   *
  1092   * 	A call to this helper is susceptible to change the underlying
  1093   * 	packet buffer. Therefore, at load time, all checks on pointers
  1094   * 	previously done by the verifier are invalidated and must be
  1095   * 	performed again, if the helper is used in combination with
  1096   * 	direct packet access.
  1097   *
  1098   * Returns
  1099   * 	0 on success, or a negative error in case of failure.
  1100   */
  1101  static long (*bpf_skb_change_head)(struct __sk_buff *skb, __u32 len, __u64 flags) = (void *) 43;
  1102  
  1103  /*
  1104   * bpf_xdp_adjust_head
  1105   *
  1106   * 	Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that
  1107   * 	it is possible to use a negative value for *delta*. This helper
  1108   * 	can be used to prepare the packet for pushing or popping
  1109   * 	headers.
  1110   *
  1111   * 	A call to this helper is susceptible to change the underlying
  1112   * 	packet buffer. Therefore, at load time, all checks on pointers
  1113   * 	previously done by the verifier are invalidated and must be
  1114   * 	performed again, if the helper is used in combination with
  1115   * 	direct packet access.
  1116   *
  1117   * Returns
  1118   * 	0 on success, or a negative error in case of failure.
  1119   */
  1120  static long (*bpf_xdp_adjust_head)(struct xdp_md *xdp_md, int delta) = (void *) 44;
  1121  
  1122  /*
  1123   * bpf_probe_read_str
  1124   *
  1125   * 	Copy a NUL terminated string from an unsafe kernel address
  1126   * 	*unsafe_ptr* to *dst*. See **bpf_probe_read_kernel_str**\ () for
  1127   * 	more details.
  1128   *
  1129   * 	Generally, use **bpf_probe_read_user_str**\ () or
  1130   * 	**bpf_probe_read_kernel_str**\ () instead.
  1131   *
  1132   * Returns
  1133   * 	On success, the strictly positive length of the string,
  1134   * 	including the trailing NUL character. On error, a negative
  1135   * 	value.
  1136   */
  1137  static long (*bpf_probe_read_str)(void *dst, __u32 size, const void *unsafe_ptr) = (void *) 45;
  1138  
  1139  /*
  1140   * bpf_get_socket_cookie
  1141   *
  1142   * 	If the **struct sk_buff** pointed by *skb* has a known socket,
  1143   * 	retrieve the cookie (generated by the kernel) of this socket.
  1144   * 	If no cookie has been set yet, generate a new cookie. Once
  1145   * 	generated, the socket cookie remains stable for the life of the
  1146   * 	socket. This helper can be useful for monitoring per socket
  1147   * 	networking traffic statistics as it provides a global socket
  1148   * 	identifier that can be assumed unique.
  1149   *
  1150   * Returns
  1151   * 	A 8-byte long unique number on success, or 0 if the socket
  1152   * 	field is missing inside *skb*.
  1153   */
  1154  static __u64 (*bpf_get_socket_cookie)(void *ctx) = (void *) 46;
  1155  
  1156  /*
  1157   * bpf_get_socket_uid
  1158   *
  1159   *
  1160   * Returns
  1161   * 	The owner UID of the socket associated to *skb*. If the socket
  1162   * 	is **NULL**, or if it is not a full socket (i.e. if it is a
  1163   * 	time-wait or a request socket instead), **overflowuid** value
  1164   * 	is returned (note that **overflowuid** might also be the actual
  1165   * 	UID value for the socket).
  1166   */
  1167  static __u32 (*bpf_get_socket_uid)(struct __sk_buff *skb) = (void *) 47;
  1168  
  1169  /*
  1170   * bpf_set_hash
  1171   *
  1172   * 	Set the full hash for *skb* (set the field *skb*\ **->hash**)
  1173   * 	to value *hash*.
  1174   *
  1175   * Returns
  1176   * 	0
  1177   */
  1178  static long (*bpf_set_hash)(struct __sk_buff *skb, __u32 hash) = (void *) 48;
  1179  
  1180  /*
  1181   * bpf_setsockopt
  1182   *
  1183   * 	Emulate a call to **setsockopt()** on the socket associated to
  1184   * 	*bpf_socket*, which must be a full socket. The *level* at
  1185   * 	which the option resides and the name *optname* of the option
  1186   * 	must be specified, see **setsockopt(2)** for more information.
  1187   * 	The option value of length *optlen* is pointed by *optval*.
  1188   *
  1189   * 	*bpf_socket* should be one of the following:
  1190   *
  1191   * 	* **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
  1192   * 	* **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
  1193   * 	  and **BPF_CGROUP_INET6_CONNECT**.
  1194   *
  1195   * 	This helper actually implements a subset of **setsockopt()**.
  1196   * 	It supports the following *level*\ s:
  1197   *
  1198   * 	* **SOL_SOCKET**, which supports the following *optname*\ s:
  1199   * 	  **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
  1200   * 	  **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**,
  1201   * 	  **SO_BINDTODEVICE**, **SO_KEEPALIVE**.
  1202   * 	* **IPPROTO_TCP**, which supports the following *optname*\ s:
  1203   * 	  **TCP_CONGESTION**, **TCP_BPF_IW**,
  1204   * 	  **TCP_BPF_SNDCWND_CLAMP**, **TCP_SAVE_SYN**,
  1205   * 	  **TCP_KEEPIDLE**, **TCP_KEEPINTVL**, **TCP_KEEPCNT**,
  1206   * 	  **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**.
  1207   * 	* **IPPROTO_IP**, which supports *optname* **IP_TOS**.
  1208   * 	* **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
  1209   *
  1210   * Returns
  1211   * 	0 on success, or a negative error in case of failure.
  1212   */
  1213  static long (*bpf_setsockopt)(void *bpf_socket, int level, int optname, void *optval, int optlen) = (void *) 49;
  1214  
  1215  /*
  1216   * bpf_skb_adjust_room
  1217   *
  1218   * 	Grow or shrink the room for data in the packet associated to
  1219   * 	*skb* by *len_diff*, and according to the selected *mode*.
  1220   *
  1221   * 	By default, the helper will reset any offloaded checksum
  1222   * 	indicator of the skb to CHECKSUM_NONE. This can be avoided
  1223   * 	by the following flag:
  1224   *
  1225   * 	* **BPF_F_ADJ_ROOM_NO_CSUM_RESET**: Do not reset offloaded
  1226   * 	  checksum data of the skb to CHECKSUM_NONE.
  1227   *
  1228   * 	There are two supported modes at this time:
  1229   *
  1230   * 	* **BPF_ADJ_ROOM_MAC**: Adjust room at the mac layer
  1231   * 	  (room space is added or removed below the layer 2 header).
  1232   *
  1233   * 	* **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
  1234   * 	  (room space is added or removed below the layer 3 header).
  1235   *
  1236   * 	The following flags are supported at this time:
  1237   *
  1238   * 	* **BPF_F_ADJ_ROOM_FIXED_GSO**: Do not adjust gso_size.
  1239   * 	  Adjusting mss in this way is not allowed for datagrams.
  1240   *
  1241   * 	* **BPF_F_ADJ_ROOM_ENCAP_L3_IPV4**,
  1242   * 	  **BPF_F_ADJ_ROOM_ENCAP_L3_IPV6**:
  1243   * 	  Any new space is reserved to hold a tunnel header.
  1244   * 	  Configure skb offsets and other fields accordingly.
  1245   *
  1246   * 	* **BPF_F_ADJ_ROOM_ENCAP_L4_GRE**,
  1247   * 	  **BPF_F_ADJ_ROOM_ENCAP_L4_UDP**:
  1248   * 	  Use with ENCAP_L3 flags to further specify the tunnel type.
  1249   *
  1250   * 	* **BPF_F_ADJ_ROOM_ENCAP_L2**\ (*len*):
  1251   * 	  Use with ENCAP_L3/L4 flags to further specify the tunnel
  1252   * 	  type; *len* is the length of the inner MAC header.
  1253   *
  1254   * 	* **BPF_F_ADJ_ROOM_ENCAP_L2_ETH**:
  1255   * 	  Use with BPF_F_ADJ_ROOM_ENCAP_L2 flag to further specify the
  1256   * 	  L2 type as Ethernet.
  1257   *
  1258   * 	A call to this helper is susceptible to change the underlying
  1259   * 	packet buffer. Therefore, at load time, all checks on pointers
  1260   * 	previously done by the verifier are invalidated and must be
  1261   * 	performed again, if the helper is used in combination with
  1262   * 	direct packet access.
  1263   *
  1264   * Returns
  1265   * 	0 on success, or a negative error in case of failure.
  1266   */
  1267  static long (*bpf_skb_adjust_room)(struct __sk_buff *skb, __s32 len_diff, __u32 mode, __u64 flags) = (void *) 50;
  1268  
  1269  /*
  1270   * bpf_redirect_map
  1271   *
  1272   * 	Redirect the packet to the endpoint referenced by *map* at
  1273   * 	index *key*. Depending on its type, this *map* can contain
  1274   * 	references to net devices (for forwarding packets through other
  1275   * 	ports), or to CPUs (for redirecting XDP frames to another CPU;
  1276   * 	but this is only implemented for native XDP (with driver
  1277   * 	support) as of this writing).
  1278   *
  1279   * 	The lower two bits of *flags* are used as the return code if
  1280   * 	the map lookup fails. This is so that the return value can be
  1281   * 	one of the XDP program return codes up to **XDP_TX**, as chosen
  1282   * 	by the caller. The higher bits of *flags* can be set to
  1283   * 	BPF_F_BROADCAST or BPF_F_EXCLUDE_INGRESS as defined below.
  1284   *
  1285   * 	With BPF_F_BROADCAST the packet will be broadcasted to all the
  1286   * 	interfaces in the map, with BPF_F_EXCLUDE_INGRESS the ingress
  1287   * 	interface will be excluded when do broadcasting.
  1288   *
  1289   * 	See also **bpf_redirect**\ (), which only supports redirecting
  1290   * 	to an ifindex, but doesn't require a map to do so.
  1291   *
  1292   * Returns
  1293   * 	**XDP_REDIRECT** on success, or the value of the two lower bits
  1294   * 	of the *flags* argument on error.
  1295   */
  1296  static long (*bpf_redirect_map)(void *map, __u32 key, __u64 flags) = (void *) 51;
  1297  
  1298  /*
  1299   * bpf_sk_redirect_map
  1300   *
  1301   * 	Redirect the packet to the socket referenced by *map* (of type
  1302   * 	**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
  1303   * 	egress interfaces can be used for redirection. The
  1304   * 	**BPF_F_INGRESS** value in *flags* is used to make the
  1305   * 	distinction (ingress path is selected if the flag is present,
  1306   * 	egress path otherwise). This is the only flag supported for now.
  1307   *
  1308   * Returns
  1309   * 	**SK_PASS** on success, or **SK_DROP** on error.
  1310   */
  1311  static long (*bpf_sk_redirect_map)(struct __sk_buff *skb, void *map, __u32 key, __u64 flags) = (void *) 52;
  1312  
  1313  /*
  1314   * bpf_sock_map_update
  1315   *
  1316   * 	Add an entry to, or update a *map* referencing sockets. The
  1317   * 	*skops* is used as a new value for the entry associated to
  1318   * 	*key*. *flags* is one of:
  1319   *
  1320   * 	**BPF_NOEXIST**
  1321   * 		The entry for *key* must not exist in the map.
  1322   * 	**BPF_EXIST**
  1323   * 		The entry for *key* must already exist in the map.
  1324   * 	**BPF_ANY**
  1325   * 		No condition on the existence of the entry for *key*.
  1326   *
  1327   * 	If the *map* has eBPF programs (parser and verdict), those will
  1328   * 	be inherited by the socket being added. If the socket is
  1329   * 	already attached to eBPF programs, this results in an error.
  1330   *
  1331   * Returns
  1332   * 	0 on success, or a negative error in case of failure.
  1333   */
  1334  static long (*bpf_sock_map_update)(struct bpf_sock_ops *skops, void *map, void *key, __u64 flags) = (void *) 53;
  1335  
  1336  /*
  1337   * bpf_xdp_adjust_meta
  1338   *
  1339   * 	Adjust the address pointed by *xdp_md*\ **->data_meta** by
  1340   * 	*delta* (which can be positive or negative). Note that this
  1341   * 	operation modifies the address stored in *xdp_md*\ **->data**,
  1342   * 	so the latter must be loaded only after the helper has been
  1343   * 	called.
  1344   *
  1345   * 	The use of *xdp_md*\ **->data_meta** is optional and programs
  1346   * 	are not required to use it. The rationale is that when the
  1347   * 	packet is processed with XDP (e.g. as DoS filter), it is
  1348   * 	possible to push further meta data along with it before passing
  1349   * 	to the stack, and to give the guarantee that an ingress eBPF
  1350   * 	program attached as a TC classifier on the same device can pick
  1351   * 	this up for further post-processing. Since TC works with socket
  1352   * 	buffers, it remains possible to set from XDP the **mark** or
  1353   * 	**priority** pointers, or other pointers for the socket buffer.
  1354   * 	Having this scratch space generic and programmable allows for
  1355   * 	more flexibility as the user is free to store whatever meta
  1356   * 	data they need.
  1357   *
  1358   * 	A call to this helper is susceptible to change the underlying
  1359   * 	packet buffer. Therefore, at load time, all checks on pointers
  1360   * 	previously done by the verifier are invalidated and must be
  1361   * 	performed again, if the helper is used in combination with
  1362   * 	direct packet access.
  1363   *
  1364   * Returns
  1365   * 	0 on success, or a negative error in case of failure.
  1366   */
  1367  static long (*bpf_xdp_adjust_meta)(struct xdp_md *xdp_md, int delta) = (void *) 54;
  1368  
  1369  /*
  1370   * bpf_perf_event_read_value
  1371   *
  1372   * 	Read the value of a perf event counter, and store it into *buf*
  1373   * 	of size *buf_size*. This helper relies on a *map* of type
  1374   * 	**BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event
  1375   * 	counter is selected when *map* is updated with perf event file
  1376   * 	descriptors. The *map* is an array whose size is the number of
  1377   * 	available CPUs, and each cell contains a value relative to one
  1378   * 	CPU. The value to retrieve is indicated by *flags*, that
  1379   * 	contains the index of the CPU to look up, masked with
  1380   * 	**BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
  1381   * 	**BPF_F_CURRENT_CPU** to indicate that the value for the
  1382   * 	current CPU should be retrieved.
  1383   *
  1384   * 	This helper behaves in a way close to
  1385   * 	**bpf_perf_event_read**\ () helper, save that instead of
  1386   * 	just returning the value observed, it fills the *buf*
  1387   * 	structure. This allows for additional data to be retrieved: in
  1388   * 	particular, the enabled and running times (in *buf*\
  1389   * 	**->enabled** and *buf*\ **->running**, respectively) are
  1390   * 	copied. In general, **bpf_perf_event_read_value**\ () is
  1391   * 	recommended over **bpf_perf_event_read**\ (), which has some
  1392   * 	ABI issues and provides fewer functionalities.
  1393   *
  1394   * 	These values are interesting, because hardware PMU (Performance
  1395   * 	Monitoring Unit) counters are limited resources. When there are
  1396   * 	more PMU based perf events opened than available counters,
  1397   * 	kernel will multiplex these events so each event gets certain
  1398   * 	percentage (but not all) of the PMU time. In case that
  1399   * 	multiplexing happens, the number of samples or counter value
  1400   * 	will not reflect the case compared to when no multiplexing
  1401   * 	occurs. This makes comparison between different runs difficult.
  1402   * 	Typically, the counter value should be normalized before
  1403   * 	comparing to other experiments. The usual normalization is done
  1404   * 	as follows.
  1405   *
  1406   * 	::
  1407   *
  1408   * 		normalized_counter = counter * t_enabled / t_running
  1409   *
  1410   * 	Where t_enabled is the time enabled for event and t_running is
  1411   * 	the time running for event since last normalization. The
  1412   * 	enabled and running times are accumulated since the perf event
  1413   * 	open. To achieve scaling factor between two invocations of an
  1414   * 	eBPF program, users can use CPU id as the key (which is
  1415   * 	typical for perf array usage model) to remember the previous
  1416   * 	value and do the calculation inside the eBPF program.
  1417   *
  1418   * Returns
  1419   * 	0 on success, or a negative error in case of failure.
  1420   */
  1421  static long (*bpf_perf_event_read_value)(void *map, __u64 flags, struct bpf_perf_event_value *buf, __u32 buf_size) = (void *) 55;
  1422  
  1423  /*
  1424   * bpf_perf_prog_read_value
  1425   *
  1426   * 	For en eBPF program attached to a perf event, retrieve the
  1427   * 	value of the event counter associated to *ctx* and store it in
  1428   * 	the structure pointed by *buf* and of size *buf_size*. Enabled
  1429   * 	and running times are also stored in the structure (see
  1430   * 	description of helper **bpf_perf_event_read_value**\ () for
  1431   * 	more details).
  1432   *
  1433   * Returns
  1434   * 	0 on success, or a negative error in case of failure.
  1435   */
  1436  static long (*bpf_perf_prog_read_value)(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, __u32 buf_size) = (void *) 56;
  1437  
  1438  /*
  1439   * bpf_getsockopt
  1440   *
  1441   * 	Emulate a call to **getsockopt()** on the socket associated to
  1442   * 	*bpf_socket*, which must be a full socket. The *level* at
  1443   * 	which the option resides and the name *optname* of the option
  1444   * 	must be specified, see **getsockopt(2)** for more information.
  1445   * 	The retrieved value is stored in the structure pointed by
  1446   * 	*opval* and of length *optlen*.
  1447   *
  1448   * 	*bpf_socket* should be one of the following:
  1449   *
  1450   * 	* **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
  1451   * 	* **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
  1452   * 	  and **BPF_CGROUP_INET6_CONNECT**.
  1453   *
  1454   * 	This helper actually implements a subset of **getsockopt()**.
  1455   * 	It supports the following *level*\ s:
  1456   *
  1457   * 	* **IPPROTO_TCP**, which supports *optname*
  1458   * 	  **TCP_CONGESTION**.
  1459   * 	* **IPPROTO_IP**, which supports *optname* **IP_TOS**.
  1460   * 	* **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
  1461   *
  1462   * Returns
  1463   * 	0 on success, or a negative error in case of failure.
  1464   */
  1465  static long (*bpf_getsockopt)(void *bpf_socket, int level, int optname, void *optval, int optlen) = (void *) 57;
  1466  
  1467  /*
  1468   * bpf_override_return
  1469   *
  1470   * 	Used for error injection, this helper uses kprobes to override
  1471   * 	the return value of the probed function, and to set it to *rc*.
  1472   * 	The first argument is the context *regs* on which the kprobe
  1473   * 	works.
  1474   *
  1475   * 	This helper works by setting the PC (program counter)
  1476   * 	to an override function which is run in place of the original
  1477   * 	probed function. This means the probed function is not run at
  1478   * 	all. The replacement function just returns with the required
  1479   * 	value.
  1480   *
  1481   * 	This helper has security implications, and thus is subject to
  1482   * 	restrictions. It is only available if the kernel was compiled
  1483   * 	with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration
  1484   * 	option, and in this case it only works on functions tagged with
  1485   * 	**ALLOW_ERROR_INJECTION** in the kernel code.
  1486   *
  1487   * 	Also, the helper is only available for the architectures having
  1488   * 	the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
  1489   * 	x86 architecture is the only one to support this feature.
  1490   *
  1491   * Returns
  1492   * 	0
  1493   */
  1494  static long (*bpf_override_return)(struct pt_regs *regs, __u64 rc) = (void *) 58;
  1495  
  1496  /*
  1497   * bpf_sock_ops_cb_flags_set
  1498   *
  1499   * 	Attempt to set the value of the **bpf_sock_ops_cb_flags** field
  1500   * 	for the full TCP socket associated to *bpf_sock_ops* to
  1501   * 	*argval*.
  1502   *
  1503   * 	The primary use of this field is to determine if there should
  1504   * 	be calls to eBPF programs of type
  1505   * 	**BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP
  1506   * 	code. A program of the same type can change its value, per
  1507   * 	connection and as necessary, when the connection is
  1508   * 	established. This field is directly accessible for reading, but
  1509   * 	this helper must be used for updates in order to return an
  1510   * 	error if an eBPF program tries to set a callback that is not
  1511   * 	supported in the current kernel.
  1512   *
  1513   * 	*argval* is a flag array which can combine these flags:
  1514   *
  1515   * 	* **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out)
  1516   * 	* **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission)
  1517   * 	* **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change)
  1518   * 	* **BPF_SOCK_OPS_RTT_CB_FLAG** (every RTT)
  1519   *
  1520   * 	Therefore, this function can be used to clear a callback flag by
  1521   * 	setting the appropriate bit to zero. e.g. to disable the RTO
  1522   * 	callback:
  1523   *
  1524   * 	**bpf_sock_ops_cb_flags_set(bpf_sock,**
  1525   * 		**bpf_sock->bpf_sock_ops_cb_flags & ~BPF_SOCK_OPS_RTO_CB_FLAG)**
  1526   *
  1527   * 	Here are some examples of where one could call such eBPF
  1528   * 	program:
  1529   *
  1530   * 	* When RTO fires.
  1531   * 	* When a packet is retransmitted.
  1532   * 	* When the connection terminates.
  1533   * 	* When a packet is sent.
  1534   * 	* When a packet is received.
  1535   *
  1536   * Returns
  1537   * 	Code **-EINVAL** if the socket is not a full TCP socket;
  1538   * 	otherwise, a positive number containing the bits that could not
  1539   * 	be set is returned (which comes down to 0 if all bits were set
  1540   * 	as required).
  1541   */
  1542  static long (*bpf_sock_ops_cb_flags_set)(struct bpf_sock_ops *bpf_sock, int argval) = (void *) 59;
  1543  
  1544  /*
  1545   * bpf_msg_redirect_map
  1546   *
  1547   * 	This helper is used in programs implementing policies at the
  1548   * 	socket level. If the message *msg* is allowed to pass (i.e. if
  1549   * 	the verdict eBPF program returns **SK_PASS**), redirect it to
  1550   * 	the socket referenced by *map* (of type
  1551   * 	**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
  1552   * 	egress interfaces can be used for redirection. The
  1553   * 	**BPF_F_INGRESS** value in *flags* is used to make the
  1554   * 	distinction (ingress path is selected if the flag is present,
  1555   * 	egress path otherwise). This is the only flag supported for now.
  1556   *
  1557   * Returns
  1558   * 	**SK_PASS** on success, or **SK_DROP** on error.
  1559   */
  1560  static long (*bpf_msg_redirect_map)(struct sk_msg_md *msg, void *map, __u32 key, __u64 flags) = (void *) 60;
  1561  
  1562  /*
  1563   * bpf_msg_apply_bytes
  1564   *
  1565   * 	For socket policies, apply the verdict of the eBPF program to
  1566   * 	the next *bytes* (number of bytes) of message *msg*.
  1567   *
  1568   * 	For example, this helper can be used in the following cases:
  1569   *
  1570   * 	* A single **sendmsg**\ () or **sendfile**\ () system call
  1571   * 	  contains multiple logical messages that the eBPF program is
  1572   * 	  supposed to read and for which it should apply a verdict.
  1573   * 	* An eBPF program only cares to read the first *bytes* of a
  1574   * 	  *msg*. If the message has a large payload, then setting up
  1575   * 	  and calling the eBPF program repeatedly for all bytes, even
  1576   * 	  though the verdict is already known, would create unnecessary
  1577   * 	  overhead.
  1578   *
  1579   * 	When called from within an eBPF program, the helper sets a
  1580   * 	counter internal to the BPF infrastructure, that is used to
  1581   * 	apply the last verdict to the next *bytes*. If *bytes* is
  1582   * 	smaller than the current data being processed from a
  1583   * 	**sendmsg**\ () or **sendfile**\ () system call, the first
  1584   * 	*bytes* will be sent and the eBPF program will be re-run with
  1585   * 	the pointer for start of data pointing to byte number *bytes*
  1586   * 	**+ 1**. If *bytes* is larger than the current data being
  1587   * 	processed, then the eBPF verdict will be applied to multiple
  1588   * 	**sendmsg**\ () or **sendfile**\ () calls until *bytes* are
  1589   * 	consumed.
  1590   *
  1591   * 	Note that if a socket closes with the internal counter holding
  1592   * 	a non-zero value, this is not a problem because data is not
  1593   * 	being buffered for *bytes* and is sent as it is received.
  1594   *
  1595   * Returns
  1596   * 	0
  1597   */
  1598  static long (*bpf_msg_apply_bytes)(struct sk_msg_md *msg, __u32 bytes) = (void *) 61;
  1599  
  1600  /*
  1601   * bpf_msg_cork_bytes
  1602   *
  1603   * 	For socket policies, prevent the execution of the verdict eBPF
  1604   * 	program for message *msg* until *bytes* (byte number) have been
  1605   * 	accumulated.
  1606   *
  1607   * 	This can be used when one needs a specific number of bytes
  1608   * 	before a verdict can be assigned, even if the data spans
  1609   * 	multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme
  1610   * 	case would be a user calling **sendmsg**\ () repeatedly with
  1611   * 	1-byte long message segments. Obviously, this is bad for
  1612   * 	performance, but it is still valid. If the eBPF program needs
  1613   * 	*bytes* bytes to validate a header, this helper can be used to
  1614   * 	prevent the eBPF program to be called again until *bytes* have
  1615   * 	been accumulated.
  1616   *
  1617   * Returns
  1618   * 	0
  1619   */
  1620  static long (*bpf_msg_cork_bytes)(struct sk_msg_md *msg, __u32 bytes) = (void *) 62;
  1621  
  1622  /*
  1623   * bpf_msg_pull_data
  1624   *
  1625   * 	For socket policies, pull in non-linear data from user space
  1626   * 	for *msg* and set pointers *msg*\ **->data** and *msg*\
  1627   * 	**->data_end** to *start* and *end* bytes offsets into *msg*,
  1628   * 	respectively.
  1629   *
  1630   * 	If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
  1631   * 	*msg* it can only parse data that the (**data**, **data_end**)
  1632   * 	pointers have already consumed. For **sendmsg**\ () hooks this
  1633   * 	is likely the first scatterlist element. But for calls relying
  1634   * 	on the **sendpage** handler (e.g. **sendfile**\ ()) this will
  1635   * 	be the range (**0**, **0**) because the data is shared with
  1636   * 	user space and by default the objective is to avoid allowing
  1637   * 	user space to modify data while (or after) eBPF verdict is
  1638   * 	being decided. This helper can be used to pull in data and to
  1639   * 	set the start and end pointer to given values. Data will be
  1640   * 	copied if necessary (i.e. if data was not linear and if start
  1641   * 	and end pointers do not point to the same chunk).
  1642   *
  1643   * 	A call to this helper is susceptible to change the underlying
  1644   * 	packet buffer. Therefore, at load time, all checks on pointers
  1645   * 	previously done by the verifier are invalidated and must be
  1646   * 	performed again, if the helper is used in combination with
  1647   * 	direct packet access.
  1648   *
  1649   * 	All values for *flags* are reserved for future usage, and must
  1650   * 	be left at zero.
  1651   *
  1652   * Returns
  1653   * 	0 on success, or a negative error in case of failure.
  1654   */
  1655  static long (*bpf_msg_pull_data)(struct sk_msg_md *msg, __u32 start, __u32 end, __u64 flags) = (void *) 63;
  1656  
  1657  /*
  1658   * bpf_bind
  1659   *
  1660   * 	Bind the socket associated to *ctx* to the address pointed by
  1661   * 	*addr*, of length *addr_len*. This allows for making outgoing
  1662   * 	connection from the desired IP address, which can be useful for
  1663   * 	example when all processes inside a cgroup should use one
  1664   * 	single IP address on a host that has multiple IP configured.
  1665   *
  1666   * 	This helper works for IPv4 and IPv6, TCP and UDP sockets. The
  1667   * 	domain (*addr*\ **->sa_family**) must be **AF_INET** (or
  1668   * 	**AF_INET6**). It's advised to pass zero port (**sin_port**
  1669   * 	or **sin6_port**) which triggers IP_BIND_ADDRESS_NO_PORT-like
  1670   * 	behavior and lets the kernel efficiently pick up an unused
  1671   * 	port as long as 4-tuple is unique. Passing non-zero port might
  1672   * 	lead to degraded performance.
  1673   *
  1674   * Returns
  1675   * 	0 on success, or a negative error in case of failure.
  1676   */
  1677  static long (*bpf_bind)(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len) = (void *) 64;
  1678  
  1679  /*
  1680   * bpf_xdp_adjust_tail
  1681   *
  1682   * 	Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is
  1683   * 	possible to both shrink and grow the packet tail.
  1684   * 	Shrink done via *delta* being a negative integer.
  1685   *
  1686   * 	A call to this helper is susceptible to change the underlying
  1687   * 	packet buffer. Therefore, at load time, all checks on pointers
  1688   * 	previously done by the verifier are invalidated and must be
  1689   * 	performed again, if the helper is used in combination with
  1690   * 	direct packet access.
  1691   *
  1692   * Returns
  1693   * 	0 on success, or a negative error in case of failure.
  1694   */
  1695  static long (*bpf_xdp_adjust_tail)(struct xdp_md *xdp_md, int delta) = (void *) 65;
  1696  
  1697  /*
  1698   * bpf_skb_get_xfrm_state
  1699   *
  1700   * 	Retrieve the XFRM state (IP transform framework, see also
  1701   * 	**ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*.
  1702   *
  1703   * 	The retrieved value is stored in the **struct bpf_xfrm_state**
  1704   * 	pointed by *xfrm_state* and of length *size*.
  1705   *
  1706   * 	All values for *flags* are reserved for future usage, and must
  1707   * 	be left at zero.
  1708   *
  1709   * 	This helper is available only if the kernel was compiled with
  1710   * 	**CONFIG_XFRM** configuration option.
  1711   *
  1712   * Returns
  1713   * 	0 on success, or a negative error in case of failure.
  1714   */
  1715  static long (*bpf_skb_get_xfrm_state)(struct __sk_buff *skb, __u32 index, struct bpf_xfrm_state *xfrm_state, __u32 size, __u64 flags) = (void *) 66;
  1716  
  1717  /*
  1718   * bpf_get_stack
  1719   *
  1720   * 	Return a user or a kernel stack in bpf program provided buffer.
  1721   * 	To achieve this, the helper needs *ctx*, which is a pointer
  1722   * 	to the context on which the tracing program is executed.
  1723   * 	To store the stacktrace, the bpf program provides *buf* with
  1724   * 	a nonnegative *size*.
  1725   *
  1726   * 	The last argument, *flags*, holds the number of stack frames to
  1727   * 	skip (from 0 to 255), masked with
  1728   * 	**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
  1729   * 	the following flags:
  1730   *
  1731   * 	**BPF_F_USER_STACK**
  1732   * 		Collect a user space stack instead of a kernel stack.
  1733   * 	**BPF_F_USER_BUILD_ID**
  1734   * 		Collect buildid+offset instead of ips for user stack,
  1735   * 		only valid if **BPF_F_USER_STACK** is also specified.
  1736   *
  1737   * 	**bpf_get_stack**\ () can collect up to
  1738   * 	**PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
  1739   * 	to sufficient large buffer size. Note that
  1740   * 	this limit can be controlled with the **sysctl** program, and
  1741   * 	that it should be manually increased in order to profile long
  1742   * 	user stacks (such as stacks for Java programs). To do so, use:
  1743   *
  1744   * 	::
  1745   *
  1746   * 		# sysctl kernel.perf_event_max_stack=<new value>
  1747   *
  1748   * Returns
  1749   * 	A non-negative value equal to or less than *size* on success,
  1750   * 	or a negative error in case of failure.
  1751   */
  1752  static long (*bpf_get_stack)(void *ctx, void *buf, __u32 size, __u64 flags) = (void *) 67;
  1753  
  1754  /*
  1755   * bpf_skb_load_bytes_relative
  1756   *
  1757   * 	This helper is similar to **bpf_skb_load_bytes**\ () in that
  1758   * 	it provides an easy way to load *len* bytes from *offset*
  1759   * 	from the packet associated to *skb*, into the buffer pointed
  1760   * 	by *to*. The difference to **bpf_skb_load_bytes**\ () is that
  1761   * 	a fifth argument *start_header* exists in order to select a
  1762   * 	base offset to start from. *start_header* can be one of:
  1763   *
  1764   * 	**BPF_HDR_START_MAC**
  1765   * 		Base offset to load data from is *skb*'s mac header.
  1766   * 	**BPF_HDR_START_NET**
  1767   * 		Base offset to load data from is *skb*'s network header.
  1768   *
  1769   * 	In general, "direct packet access" is the preferred method to
  1770   * 	access packet data, however, this helper is in particular useful
  1771   * 	in socket filters where *skb*\ **->data** does not always point
  1772   * 	to the start of the mac header and where "direct packet access"
  1773   * 	is not available.
  1774   *
  1775   * Returns
  1776   * 	0 on success, or a negative error in case of failure.
  1777   */
  1778  static long (*bpf_skb_load_bytes_relative)(const void *skb, __u32 offset, void *to, __u32 len, __u32 start_header) = (void *) 68;
  1779  
  1780  /*
  1781   * bpf_fib_lookup
  1782   *
  1783   * 	Do FIB lookup in kernel tables using parameters in *params*.
  1784   * 	If lookup is successful and result shows packet is to be
  1785   * 	forwarded, the neighbor tables are searched for the nexthop.
  1786   * 	If successful (ie., FIB lookup shows forwarding and nexthop
  1787   * 	is resolved), the nexthop address is returned in ipv4_dst
  1788   * 	or ipv6_dst based on family, smac is set to mac address of
  1789   * 	egress device, dmac is set to nexthop mac address, rt_metric
  1790   * 	is set to metric from route (IPv4/IPv6 only), and ifindex
  1791   * 	is set to the device index of the nexthop from the FIB lookup.
  1792   *
  1793   * 	*plen* argument is the size of the passed in struct.
  1794   * 	*flags* argument can be a combination of one or more of the
  1795   * 	following values:
  1796   *
  1797   * 	**BPF_FIB_LOOKUP_DIRECT**
  1798   * 		Do a direct table lookup vs full lookup using FIB
  1799   * 		rules.
  1800   * 	**BPF_FIB_LOOKUP_OUTPUT**
  1801   * 		Perform lookup from an egress perspective (default is
  1802   * 		ingress).
  1803   *
  1804   * 	*ctx* is either **struct xdp_md** for XDP programs or
  1805   * 	**struct sk_buff** tc cls_act programs.
  1806   *
  1807   * Returns
  1808   * 	* < 0 if any input argument is invalid
  1809   * 	*   0 on success (packet is forwarded, nexthop neighbor exists)
  1810   * 	* > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
  1811   * 	  packet is not forwarded or needs assist from full stack
  1812   *
  1813   * 	If lookup fails with BPF_FIB_LKUP_RET_FRAG_NEEDED, then the MTU
  1814   * 	was exceeded and output params->mtu_result contains the MTU.
  1815   */
  1816  static long (*bpf_fib_lookup)(void *ctx, struct bpf_fib_lookup *params, int plen, __u32 flags) = (void *) 69;
  1817  
  1818  /*
  1819   * bpf_sock_hash_update
  1820   *
  1821   * 	Add an entry to, or update a sockhash *map* referencing sockets.
  1822   * 	The *skops* is used as a new value for the entry associated to
  1823   * 	*key*. *flags* is one of:
  1824   *
  1825   * 	**BPF_NOEXIST**
  1826   * 		The entry for *key* must not exist in the map.
  1827   * 	**BPF_EXIST**
  1828   * 		The entry for *key* must already exist in the map.
  1829   * 	**BPF_ANY**
  1830   * 		No condition on the existence of the entry for *key*.
  1831   *
  1832   * 	If the *map* has eBPF programs (parser and verdict), those will
  1833   * 	be inherited by the socket being added. If the socket is
  1834   * 	already attached to eBPF programs, this results in an error.
  1835   *
  1836   * Returns
  1837   * 	0 on success, or a negative error in case of failure.
  1838   */
  1839  static long (*bpf_sock_hash_update)(struct bpf_sock_ops *skops, void *map, void *key, __u64 flags) = (void *) 70;
  1840  
  1841  /*
  1842   * bpf_msg_redirect_hash
  1843   *
  1844   * 	This helper is used in programs implementing policies at the
  1845   * 	socket level. If the message *msg* is allowed to pass (i.e. if
  1846   * 	the verdict eBPF program returns **SK_PASS**), redirect it to
  1847   * 	the socket referenced by *map* (of type
  1848   * 	**BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
  1849   * 	egress interfaces can be used for redirection. The
  1850   * 	**BPF_F_INGRESS** value in *flags* is used to make the
  1851   * 	distinction (ingress path is selected if the flag is present,
  1852   * 	egress path otherwise). This is the only flag supported for now.
  1853   *
  1854   * Returns
  1855   * 	**SK_PASS** on success, or **SK_DROP** on error.
  1856   */
  1857  static long (*bpf_msg_redirect_hash)(struct sk_msg_md *msg, void *map, void *key, __u64 flags) = (void *) 71;
  1858  
  1859  /*
  1860   * bpf_sk_redirect_hash
  1861   *
  1862   * 	This helper is used in programs implementing policies at the
  1863   * 	skb socket level. If the sk_buff *skb* is allowed to pass (i.e.
  1864   * 	if the verdict eBPF program returns **SK_PASS**), redirect it
  1865   * 	to the socket referenced by *map* (of type
  1866   * 	**BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
  1867   * 	egress interfaces can be used for redirection. The
  1868   * 	**BPF_F_INGRESS** value in *flags* is used to make the
  1869   * 	distinction (ingress path is selected if the flag is present,
  1870   * 	egress otherwise). This is the only flag supported for now.
  1871   *
  1872   * Returns
  1873   * 	**SK_PASS** on success, or **SK_DROP** on error.
  1874   */
  1875  static long (*bpf_sk_redirect_hash)(struct __sk_buff *skb, void *map, void *key, __u64 flags) = (void *) 72;
  1876  
  1877  /*
  1878   * bpf_lwt_push_encap
  1879   *
  1880   * 	Encapsulate the packet associated to *skb* within a Layer 3
  1881   * 	protocol header. This header is provided in the buffer at
  1882   * 	address *hdr*, with *len* its size in bytes. *type* indicates
  1883   * 	the protocol of the header and can be one of:
  1884   *
  1885   * 	**BPF_LWT_ENCAP_SEG6**
  1886   * 		IPv6 encapsulation with Segment Routing Header
  1887   * 		(**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
  1888   * 		the IPv6 header is computed by the kernel.
  1889   * 	**BPF_LWT_ENCAP_SEG6_INLINE**
  1890   * 		Only works if *skb* contains an IPv6 packet. Insert a
  1891   * 		Segment Routing Header (**struct ipv6_sr_hdr**) inside
  1892   * 		the IPv6 header.
  1893   * 	**BPF_LWT_ENCAP_IP**
  1894   * 		IP encapsulation (GRE/GUE/IPIP/etc). The outer header
  1895   * 		must be IPv4 or IPv6, followed by zero or more
  1896   * 		additional headers, up to **LWT_BPF_MAX_HEADROOM**
  1897   * 		total bytes in all prepended headers. Please note that
  1898   * 		if **skb_is_gso**\ (*skb*) is true, no more than two
  1899   * 		headers can be prepended, and the inner header, if
  1900   * 		present, should be either GRE or UDP/GUE.
  1901   *
  1902   * 	**BPF_LWT_ENCAP_SEG6**\ \* types can be called by BPF programs
  1903   * 	of type **BPF_PROG_TYPE_LWT_IN**; **BPF_LWT_ENCAP_IP** type can
  1904   * 	be called by bpf programs of types **BPF_PROG_TYPE_LWT_IN** and
  1905   * 	**BPF_PROG_TYPE_LWT_XMIT**.
  1906   *
  1907   * 	A call to this helper is susceptible to change the underlying
  1908   * 	packet buffer. Therefore, at load time, all checks on pointers
  1909   * 	previously done by the verifier are invalidated and must be
  1910   * 	performed again, if the helper is used in combination with
  1911   * 	direct packet access.
  1912   *
  1913   * Returns
  1914   * 	0 on success, or a negative error in case of failure.
  1915   */
  1916  static long (*bpf_lwt_push_encap)(struct __sk_buff *skb, __u32 type, void *hdr, __u32 len) = (void *) 73;
  1917  
  1918  /*
  1919   * bpf_lwt_seg6_store_bytes
  1920   *
  1921   * 	Store *len* bytes from address *from* into the packet
  1922   * 	associated to *skb*, at *offset*. Only the flags, tag and TLVs
  1923   * 	inside the outermost IPv6 Segment Routing Header can be
  1924   * 	modified through this helper.
  1925   *
  1926   * 	A call to this helper is susceptible to change the underlying
  1927   * 	packet buffer. Therefore, at load time, all checks on pointers
  1928   * 	previously done by the verifier are invalidated and must be
  1929   * 	performed again, if the helper is used in combination with
  1930   * 	direct packet access.
  1931   *
  1932   * Returns
  1933   * 	0 on success, or a negative error in case of failure.
  1934   */
  1935  static long (*bpf_lwt_seg6_store_bytes)(struct __sk_buff *skb, __u32 offset, const void *from, __u32 len) = (void *) 74;
  1936  
  1937  /*
  1938   * bpf_lwt_seg6_adjust_srh
  1939   *
  1940   * 	Adjust the size allocated to TLVs in the outermost IPv6
  1941   * 	Segment Routing Header contained in the packet associated to
  1942   * 	*skb*, at position *offset* by *delta* bytes. Only offsets
  1943   * 	after the segments are accepted. *delta* can be as well
  1944   * 	positive (growing) as negative (shrinking).
  1945   *
  1946   * 	A call to this helper is susceptible to change the underlying
  1947   * 	packet buffer. Therefore, at load time, all checks on pointers
  1948   * 	previously done by the verifier are invalidated and must be
  1949   * 	performed again, if the helper is used in combination with
  1950   * 	direct packet access.
  1951   *
  1952   * Returns
  1953   * 	0 on success, or a negative error in case of failure.
  1954   */
  1955  static long (*bpf_lwt_seg6_adjust_srh)(struct __sk_buff *skb, __u32 offset, __s32 delta) = (void *) 75;
  1956  
  1957  /*
  1958   * bpf_lwt_seg6_action
  1959   *
  1960   * 	Apply an IPv6 Segment Routing action of type *action* to the
  1961   * 	packet associated to *skb*. Each action takes a parameter
  1962   * 	contained at address *param*, and of length *param_len* bytes.
  1963   * 	*action* can be one of:
  1964   *
  1965   * 	**SEG6_LOCAL_ACTION_END_X**
  1966   * 		End.X action: Endpoint with Layer-3 cross-connect.
  1967   * 		Type of *param*: **struct in6_addr**.
  1968   * 	**SEG6_LOCAL_ACTION_END_T**
  1969   * 		End.T action: Endpoint with specific IPv6 table lookup.
  1970   * 		Type of *param*: **int**.
  1971   * 	**SEG6_LOCAL_ACTION_END_B6**
  1972   * 		End.B6 action: Endpoint bound to an SRv6 policy.
  1973   * 		Type of *param*: **struct ipv6_sr_hdr**.
  1974   * 	**SEG6_LOCAL_ACTION_END_B6_ENCAP**
  1975   * 		End.B6.Encap action: Endpoint bound to an SRv6
  1976   * 		encapsulation policy.
  1977   * 		Type of *param*: **struct ipv6_sr_hdr**.
  1978   *
  1979   * 	A call to this helper is susceptible to change the underlying
  1980   * 	packet buffer. Therefore, at load time, all checks on pointers
  1981   * 	previously done by the verifier are invalidated and must be
  1982   * 	performed again, if the helper is used in combination with
  1983   * 	direct packet access.
  1984   *
  1985   * Returns
  1986   * 	0 on success, or a negative error in case of failure.
  1987   */
  1988  static long (*bpf_lwt_seg6_action)(struct __sk_buff *skb, __u32 action, void *param, __u32 param_len) = (void *) 76;
  1989  
  1990  /*
  1991   * bpf_rc_repeat
  1992   *
  1993   * 	This helper is used in programs implementing IR decoding, to
  1994   * 	report a successfully decoded repeat key message. This delays
  1995   * 	the generation of a key up event for previously generated
  1996   * 	key down event.
  1997   *
  1998   * 	Some IR protocols like NEC have a special IR message for
  1999   * 	repeating last button, for when a button is held down.
  2000   *
  2001   * 	The *ctx* should point to the lirc sample as passed into
  2002   * 	the program.
  2003   *
  2004   * 	This helper is only available is the kernel was compiled with
  2005   * 	the **CONFIG_BPF_LIRC_MODE2** configuration option set to
  2006   * 	"**y**".
  2007   *
  2008   * Returns
  2009   * 	0
  2010   */
  2011  static long (*bpf_rc_repeat)(void *ctx) = (void *) 77;
  2012  
  2013  /*
  2014   * bpf_rc_keydown
  2015   *
  2016   * 	This helper is used in programs implementing IR decoding, to
  2017   * 	report a successfully decoded key press with *scancode*,
  2018   * 	*toggle* value in the given *protocol*. The scancode will be
  2019   * 	translated to a keycode using the rc keymap, and reported as
  2020   * 	an input key down event. After a period a key up event is
  2021   * 	generated. This period can be extended by calling either
  2022   * 	**bpf_rc_keydown**\ () again with the same values, or calling
  2023   * 	**bpf_rc_repeat**\ ().
  2024   *
  2025   * 	Some protocols include a toggle bit, in case the button was
  2026   * 	released and pressed again between consecutive scancodes.
  2027   *
  2028   * 	The *ctx* should point to the lirc sample as passed into
  2029   * 	the program.
  2030   *
  2031   * 	The *protocol* is the decoded protocol number (see
  2032   * 	**enum rc_proto** for some predefined values).
  2033   *
  2034   * 	This helper is only available is the kernel was compiled with
  2035   * 	the **CONFIG_BPF_LIRC_MODE2** configuration option set to
  2036   * 	"**y**".
  2037   *
  2038   * Returns
  2039   * 	0
  2040   */
  2041  static long (*bpf_rc_keydown)(void *ctx, __u32 protocol, __u64 scancode, __u32 toggle) = (void *) 78;
  2042  
  2043  /*
  2044   * bpf_skb_cgroup_id
  2045   *
  2046   * 	Return the cgroup v2 id of the socket associated with the *skb*.
  2047   * 	This is roughly similar to the **bpf_get_cgroup_classid**\ ()
  2048   * 	helper for cgroup v1 by providing a tag resp. identifier that
  2049   * 	can be matched on or used for map lookups e.g. to implement
  2050   * 	policy. The cgroup v2 id of a given path in the hierarchy is
  2051   * 	exposed in user space through the f_handle API in order to get
  2052   * 	to the same 64-bit id.
  2053   *
  2054   * 	This helper can be used on TC egress path, but not on ingress,
  2055   * 	and is available only if the kernel was compiled with the
  2056   * 	**CONFIG_SOCK_CGROUP_DATA** configuration option.
  2057   *
  2058   * Returns
  2059   * 	The id is returned or 0 in case the id could not be retrieved.
  2060   */
  2061  static __u64 (*bpf_skb_cgroup_id)(struct __sk_buff *skb) = (void *) 79;
  2062  
  2063  /*
  2064   * bpf_get_current_cgroup_id
  2065   *
  2066   *
  2067   * Returns
  2068   * 	A 64-bit integer containing the current cgroup id based
  2069   * 	on the cgroup within which the current task is running.
  2070   */
  2071  static __u64 (*bpf_get_current_cgroup_id)(void) = (void *) 80;
  2072  
  2073  /*
  2074   * bpf_get_local_storage
  2075   *
  2076   * 	Get the pointer to the local storage area.
  2077   * 	The type and the size of the local storage is defined
  2078   * 	by the *map* argument.
  2079   * 	The *flags* meaning is specific for each map type,
  2080   * 	and has to be 0 for cgroup local storage.
  2081   *
  2082   * 	Depending on the BPF program type, a local storage area
  2083   * 	can be shared between multiple instances of the BPF program,
  2084   * 	running simultaneously.
  2085   *
  2086   * 	A user should care about the synchronization by himself.
  2087   * 	For example, by using the **BPF_ATOMIC** instructions to alter
  2088   * 	the shared data.
  2089   *
  2090   * Returns
  2091   * 	A pointer to the local storage area.
  2092   */
  2093  static void *(*bpf_get_local_storage)(void *map, __u64 flags) = (void *) 81;
  2094  
  2095  /*
  2096   * bpf_sk_select_reuseport
  2097   *
  2098   * 	Select a **SO_REUSEPORT** socket from a
  2099   * 	**BPF_MAP_TYPE_REUSEPORT_SOCKARRAY** *map*.
  2100   * 	It checks the selected socket is matching the incoming
  2101   * 	request in the socket buffer.
  2102   *
  2103   * Returns
  2104   * 	0 on success, or a negative error in case of failure.
  2105   */
  2106  static long (*bpf_sk_select_reuseport)(struct sk_reuseport_md *reuse, void *map, void *key, __u64 flags) = (void *) 82;
  2107  
  2108  /*
  2109   * bpf_skb_ancestor_cgroup_id
  2110   *
  2111   * 	Return id of cgroup v2 that is ancestor of cgroup associated
  2112   * 	with the *skb* at the *ancestor_level*.  The root cgroup is at
  2113   * 	*ancestor_level* zero and each step down the hierarchy
  2114   * 	increments the level. If *ancestor_level* == level of cgroup
  2115   * 	associated with *skb*, then return value will be same as that
  2116   * 	of **bpf_skb_cgroup_id**\ ().
  2117   *
  2118   * 	The helper is useful to implement policies based on cgroups
  2119   * 	that are upper in hierarchy than immediate cgroup associated
  2120   * 	with *skb*.
  2121   *
  2122   * 	The format of returned id and helper limitations are same as in
  2123   * 	**bpf_skb_cgroup_id**\ ().
  2124   *
  2125   * Returns
  2126   * 	The id is returned or 0 in case the id could not be retrieved.
  2127   */
  2128  static __u64 (*bpf_skb_ancestor_cgroup_id)(struct __sk_buff *skb, int ancestor_level) = (void *) 83;
  2129  
  2130  /*
  2131   * bpf_sk_lookup_tcp
  2132   *
  2133   * 	Look for TCP socket matching *tuple*, optionally in a child
  2134   * 	network namespace *netns*. The return value must be checked,
  2135   * 	and if non-**NULL**, released via **bpf_sk_release**\ ().
  2136   *
  2137   * 	The *ctx* should point to the context of the program, such as
  2138   * 	the skb or socket (depending on the hook in use). This is used
  2139   * 	to determine the base network namespace for the lookup.
  2140   *
  2141   * 	*tuple_size* must be one of:
  2142   *
  2143   * 	**sizeof**\ (*tuple*\ **->ipv4**)
  2144   * 		Look for an IPv4 socket.
  2145   * 	**sizeof**\ (*tuple*\ **->ipv6**)
  2146   * 		Look for an IPv6 socket.
  2147   *
  2148   * 	If the *netns* is a negative signed 32-bit integer, then the
  2149   * 	socket lookup table in the netns associated with the *ctx*
  2150   * 	will be used. For the TC hooks, this is the netns of the device
  2151   * 	in the skb. For socket hooks, this is the netns of the socket.
  2152   * 	If *netns* is any other signed 32-bit value greater than or
  2153   * 	equal to zero then it specifies the ID of the netns relative to
  2154   * 	the netns associated with the *ctx*. *netns* values beyond the
  2155   * 	range of 32-bit integers are reserved for future use.
  2156   *
  2157   * 	All values for *flags* are reserved for future usage, and must
  2158   * 	be left at zero.
  2159   *
  2160   * 	This helper is available only if the kernel was compiled with
  2161   * 	**CONFIG_NET** configuration option.
  2162   *
  2163   * Returns
  2164   * 	Pointer to **struct bpf_sock**, or **NULL** in case of failure.
  2165   * 	For sockets with reuseport option, the **struct bpf_sock**
  2166   * 	result is from *reuse*\ **->socks**\ [] using the hash of the
  2167   * 	tuple.
  2168   */
  2169  static struct bpf_sock *(*bpf_sk_lookup_tcp)(void *ctx, struct bpf_sock_tuple *tuple, __u32 tuple_size, __u64 netns, __u64 flags) = (void *) 84;
  2170  
  2171  /*
  2172   * bpf_sk_lookup_udp
  2173   *
  2174   * 	Look for UDP socket matching *tuple*, optionally in a child
  2175   * 	network namespace *netns*. The return value must be checked,
  2176   * 	and if non-**NULL**, released via **bpf_sk_release**\ ().
  2177   *
  2178   * 	The *ctx* should point to the context of the program, such as
  2179   * 	the skb or socket (depending on the hook in use). This is used
  2180   * 	to determine the base network namespace for the lookup.
  2181   *
  2182   * 	*tuple_size* must be one of:
  2183   *
  2184   * 	**sizeof**\ (*tuple*\ **->ipv4**)
  2185   * 		Look for an IPv4 socket.
  2186   * 	**sizeof**\ (*tuple*\ **->ipv6**)
  2187   * 		Look for an IPv6 socket.
  2188   *
  2189   * 	If the *netns* is a negative signed 32-bit integer, then the
  2190   * 	socket lookup table in the netns associated with the *ctx*
  2191   * 	will be used. For the TC hooks, this is the netns of the device
  2192   * 	in the skb. For socket hooks, this is the netns of the socket.
  2193   * 	If *netns* is any other signed 32-bit value greater than or
  2194   * 	equal to zero then it specifies the ID of the netns relative to
  2195   * 	the netns associated with the *ctx*. *netns* values beyond the
  2196   * 	range of 32-bit integers are reserved for future use.
  2197   *
  2198   * 	All values for *flags* are reserved for future usage, and must
  2199   * 	be left at zero.
  2200   *
  2201   * 	This helper is available only if the kernel was compiled with
  2202   * 	**CONFIG_NET** configuration option.
  2203   *
  2204   * Returns
  2205   * 	Pointer to **struct bpf_sock**, or **NULL** in case of failure.
  2206   * 	For sockets with reuseport option, the **struct bpf_sock**
  2207   * 	result is from *reuse*\ **->socks**\ [] using the hash of the
  2208   * 	tuple.
  2209   */
  2210  static struct bpf_sock *(*bpf_sk_lookup_udp)(void *ctx, struct bpf_sock_tuple *tuple, __u32 tuple_size, __u64 netns, __u64 flags) = (void *) 85;
  2211  
  2212  /*
  2213   * bpf_sk_release
  2214   *
  2215   * 	Release the reference held by *sock*. *sock* must be a
  2216   * 	non-**NULL** pointer that was returned from
  2217   * 	**bpf_sk_lookup_xxx**\ ().
  2218   *
  2219   * Returns
  2220   * 	0 on success, or a negative error in case of failure.
  2221   */
  2222  static long (*bpf_sk_release)(void *sock) = (void *) 86;
  2223  
  2224  /*
  2225   * bpf_map_push_elem
  2226   *
  2227   * 	Push an element *value* in *map*. *flags* is one of:
  2228   *
  2229   * 	**BPF_EXIST**
  2230   * 		If the queue/stack is full, the oldest element is
  2231   * 		removed to make room for this.
  2232   *
  2233   * Returns
  2234   * 	0 on success, or a negative error in case of failure.
  2235   */
  2236  static long (*bpf_map_push_elem)(void *map, const void *value, __u64 flags) = (void *) 87;
  2237  
  2238  /*
  2239   * bpf_map_pop_elem
  2240   *
  2241   * 	Pop an element from *map*.
  2242   *
  2243   * Returns
  2244   * 	0 on success, or a negative error in case of failure.
  2245   */
  2246  static long (*bpf_map_pop_elem)(void *map, void *value) = (void *) 88;
  2247  
  2248  /*
  2249   * bpf_map_peek_elem
  2250   *
  2251   * 	Get an element from *map* without removing it.
  2252   *
  2253   * Returns
  2254   * 	0 on success, or a negative error in case of failure.
  2255   */
  2256  static long (*bpf_map_peek_elem)(void *map, void *value) = (void *) 89;
  2257  
  2258  /*
  2259   * bpf_msg_push_data
  2260   *
  2261   * 	For socket policies, insert *len* bytes into *msg* at offset
  2262   * 	*start*.
  2263   *
  2264   * 	If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
  2265   * 	*msg* it may want to insert metadata or options into the *msg*.
  2266   * 	This can later be read and used by any of the lower layer BPF
  2267   * 	hooks.
  2268   *
  2269   * 	This helper may fail if under memory pressure (a malloc
  2270   * 	fails) in these cases BPF programs will get an appropriate
  2271   * 	error and BPF programs will need to handle them.
  2272   *
  2273   * Returns
  2274   * 	0 on success, or a negative error in case of failure.
  2275   */
  2276  static long (*bpf_msg_push_data)(struct sk_msg_md *msg, __u32 start, __u32 len, __u64 flags) = (void *) 90;
  2277  
  2278  /*
  2279   * bpf_msg_pop_data
  2280   *
  2281   * 	Will remove *len* bytes from a *msg* starting at byte *start*.
  2282   * 	This may result in **ENOMEM** errors under certain situations if
  2283   * 	an allocation and copy are required due to a full ring buffer.
  2284   * 	However, the helper will try to avoid doing the allocation
  2285   * 	if possible. Other errors can occur if input parameters are
  2286   * 	invalid either due to *start* byte not being valid part of *msg*
  2287   * 	payload and/or *pop* value being to large.
  2288   *
  2289   * Returns
  2290   * 	0 on success, or a negative error in case of failure.
  2291   */
  2292  static long (*bpf_msg_pop_data)(struct sk_msg_md *msg, __u32 start, __u32 len, __u64 flags) = (void *) 91;
  2293  
  2294  /*
  2295   * bpf_rc_pointer_rel
  2296   *
  2297   * 	This helper is used in programs implementing IR decoding, to
  2298   * 	report a successfully decoded pointer movement.
  2299   *
  2300   * 	The *ctx* should point to the lirc sample as passed into
  2301   * 	the program.
  2302   *
  2303   * 	This helper is only available is the kernel was compiled with
  2304   * 	the **CONFIG_BPF_LIRC_MODE2** configuration option set to
  2305   * 	"**y**".
  2306   *
  2307   * Returns
  2308   * 	0
  2309   */
  2310  static long (*bpf_rc_pointer_rel)(void *ctx, __s32 rel_x, __s32 rel_y) = (void *) 92;
  2311  
  2312  /*
  2313   * bpf_spin_lock
  2314   *
  2315   * 	Acquire a spinlock represented by the pointer *lock*, which is
  2316   * 	stored as part of a value of a map. Taking the lock allows to
  2317   * 	safely update the rest of the fields in that value. The
  2318   * 	spinlock can (and must) later be released with a call to
  2319   * 	**bpf_spin_unlock**\ (\ *lock*\ ).
  2320   *
  2321   * 	Spinlocks in BPF programs come with a number of restrictions
  2322   * 	and constraints:
  2323   *
  2324   * 	* **bpf_spin_lock** objects are only allowed inside maps of
  2325   * 	  types **BPF_MAP_TYPE_HASH** and **BPF_MAP_TYPE_ARRAY** (this
  2326   * 	  list could be extended in the future).
  2327   * 	* BTF description of the map is mandatory.
  2328   * 	* The BPF program can take ONE lock at a time, since taking two
  2329   * 	  or more could cause dead locks.
  2330   * 	* Only one **struct bpf_spin_lock** is allowed per map element.
  2331   * 	* When the lock is taken, calls (either BPF to BPF or helpers)
  2332   * 	  are not allowed.
  2333   * 	* The **BPF_LD_ABS** and **BPF_LD_IND** instructions are not
  2334   * 	  allowed inside a spinlock-ed region.
  2335   * 	* The BPF program MUST call **bpf_spin_unlock**\ () to release
  2336   * 	  the lock, on all execution paths, before it returns.
  2337   * 	* The BPF program can access **struct bpf_spin_lock** only via
  2338   * 	  the **bpf_spin_lock**\ () and **bpf_spin_unlock**\ ()
  2339   * 	  helpers. Loading or storing data into the **struct
  2340   * 	  bpf_spin_lock** *lock*\ **;** field of a map is not allowed.
  2341   * 	* To use the **bpf_spin_lock**\ () helper, the BTF description
  2342   * 	  of the map value must be a struct and have **struct
  2343   * 	  bpf_spin_lock** *anyname*\ **;** field at the top level.
  2344   * 	  Nested lock inside another struct is not allowed.
  2345   * 	* The **struct bpf_spin_lock** *lock* field in a map value must
  2346   * 	  be aligned on a multiple of 4 bytes in that value.
  2347   * 	* Syscall with command **BPF_MAP_LOOKUP_ELEM** does not copy
  2348   * 	  the **bpf_spin_lock** field to user space.
  2349   * 	* Syscall with command **BPF_MAP_UPDATE_ELEM**, or update from
  2350   * 	  a BPF program, do not update the **bpf_spin_lock** field.
  2351   * 	* **bpf_spin_lock** cannot be on the stack or inside a
  2352   * 	  networking packet (it can only be inside of a map values).
  2353   * 	* **bpf_spin_lock** is available to root only.
  2354   * 	* Tracing programs and socket filter programs cannot use
  2355   * 	  **bpf_spin_lock**\ () due to insufficient preemption checks
  2356   * 	  (but this may change in the future).
  2357   * 	* **bpf_spin_lock** is not allowed in inner maps of map-in-map.
  2358   *
  2359   * Returns
  2360   * 	0
  2361   */
  2362  static long (*bpf_spin_lock)(struct bpf_spin_lock *lock) = (void *) 93;
  2363  
  2364  /*
  2365   * bpf_spin_unlock
  2366   *
  2367   * 	Release the *lock* previously locked by a call to
  2368   * 	**bpf_spin_lock**\ (\ *lock*\ ).
  2369   *
  2370   * Returns
  2371   * 	0
  2372   */
  2373  static long (*bpf_spin_unlock)(struct bpf_spin_lock *lock) = (void *) 94;
  2374  
  2375  /*
  2376   * bpf_sk_fullsock
  2377   *
  2378   * 	This helper gets a **struct bpf_sock** pointer such
  2379   * 	that all the fields in this **bpf_sock** can be accessed.
  2380   *
  2381   * Returns
  2382   * 	A **struct bpf_sock** pointer on success, or **NULL** in
  2383   * 	case of failure.
  2384   */
  2385  static struct bpf_sock *(*bpf_sk_fullsock)(struct bpf_sock *sk) = (void *) 95;
  2386  
  2387  /*
  2388   * bpf_tcp_sock
  2389   *
  2390   * 	This helper gets a **struct bpf_tcp_sock** pointer from a
  2391   * 	**struct bpf_sock** pointer.
  2392   *
  2393   * Returns
  2394   * 	A **struct bpf_tcp_sock** pointer on success, or **NULL** in
  2395   * 	case of failure.
  2396   */
  2397  static struct bpf_tcp_sock *(*bpf_tcp_sock)(struct bpf_sock *sk) = (void *) 96;
  2398  
  2399  /*
  2400   * bpf_skb_ecn_set_ce
  2401   *
  2402   * 	Set ECN (Explicit Congestion Notification) field of IP header
  2403   * 	to **CE** (Congestion Encountered) if current value is **ECT**
  2404   * 	(ECN Capable Transport). Otherwise, do nothing. Works with IPv6
  2405   * 	and IPv4.
  2406   *
  2407   * Returns
  2408   * 	1 if the **CE** flag is set (either by the current helper call
  2409   * 	or because it was already present), 0 if it is not set.
  2410   */
  2411  static long (*bpf_skb_ecn_set_ce)(struct __sk_buff *skb) = (void *) 97;
  2412  
  2413  /*
  2414   * bpf_get_listener_sock
  2415   *
  2416   * 	Return a **struct bpf_sock** pointer in **TCP_LISTEN** state.
  2417   * 	**bpf_sk_release**\ () is unnecessary and not allowed.
  2418   *
  2419   * Returns
  2420   * 	A **struct bpf_sock** pointer on success, or **NULL** in
  2421   * 	case of failure.
  2422   */
  2423  static struct bpf_sock *(*bpf_get_listener_sock)(struct bpf_sock *sk) = (void *) 98;
  2424  
  2425  /*
  2426   * bpf_skc_lookup_tcp
  2427   *
  2428   * 	Look for TCP socket matching *tuple*, optionally in a child
  2429   * 	network namespace *netns*. The return value must be checked,
  2430   * 	and if non-**NULL**, released via **bpf_sk_release**\ ().
  2431   *
  2432   * 	This function is identical to **bpf_sk_lookup_tcp**\ (), except
  2433   * 	that it also returns timewait or request sockets. Use
  2434   * 	**bpf_sk_fullsock**\ () or **bpf_tcp_sock**\ () to access the
  2435   * 	full structure.
  2436   *
  2437   * 	This helper is available only if the kernel was compiled with
  2438   * 	**CONFIG_NET** configuration option.
  2439   *
  2440   * Returns
  2441   * 	Pointer to **struct bpf_sock**, or **NULL** in case of failure.
  2442   * 	For sockets with reuseport option, the **struct bpf_sock**
  2443   * 	result is from *reuse*\ **->socks**\ [] using the hash of the
  2444   * 	tuple.
  2445   */
  2446  static struct bpf_sock *(*bpf_skc_lookup_tcp)(void *ctx, struct bpf_sock_tuple *tuple, __u32 tuple_size, __u64 netns, __u64 flags) = (void *) 99;
  2447  
  2448  /*
  2449   * bpf_tcp_check_syncookie
  2450   *
  2451   * 	Check whether *iph* and *th* contain a valid SYN cookie ACK for
  2452   * 	the listening socket in *sk*.
  2453   *
  2454   * 	*iph* points to the start of the IPv4 or IPv6 header, while
  2455   * 	*iph_len* contains **sizeof**\ (**struct iphdr**) or
  2456   * 	**sizeof**\ (**struct ip6hdr**).
  2457   *
  2458   * 	*th* points to the start of the TCP header, while *th_len*
  2459   * 	contains **sizeof**\ (**struct tcphdr**).
  2460   *
  2461   * Returns
  2462   * 	0 if *iph* and *th* are a valid SYN cookie ACK, or a negative
  2463   * 	error otherwise.
  2464   */
  2465  static long (*bpf_tcp_check_syncookie)(void *sk, void *iph, __u32 iph_len, struct tcphdr *th, __u32 th_len) = (void *) 100;
  2466  
  2467  /*
  2468   * bpf_sysctl_get_name
  2469   *
  2470   * 	Get name of sysctl in /proc/sys/ and copy it into provided by
  2471   * 	program buffer *buf* of size *buf_len*.
  2472   *
  2473   * 	The buffer is always NUL terminated, unless it's zero-sized.
  2474   *
  2475   * 	If *flags* is zero, full name (e.g. "net/ipv4/tcp_mem") is
  2476   * 	copied. Use **BPF_F_SYSCTL_BASE_NAME** flag to copy base name
  2477   * 	only (e.g. "tcp_mem").
  2478   *
  2479   * Returns
  2480   * 	Number of character copied (not including the trailing NUL).
  2481   *
  2482   * 	**-E2BIG** if the buffer wasn't big enough (*buf* will contain
  2483   * 	truncated name in this case).
  2484   */
  2485  static long (*bpf_sysctl_get_name)(struct bpf_sysctl *ctx, char *buf, unsigned long buf_len, __u64 flags) = (void *) 101;
  2486  
  2487  /*
  2488   * bpf_sysctl_get_current_value
  2489   *
  2490   * 	Get current value of sysctl as it is presented in /proc/sys
  2491   * 	(incl. newline, etc), and copy it as a string into provided
  2492   * 	by program buffer *buf* of size *buf_len*.
  2493   *
  2494   * 	The whole value is copied, no matter what file position user
  2495   * 	space issued e.g. sys_read at.
  2496   *
  2497   * 	The buffer is always NUL terminated, unless it's zero-sized.
  2498   *
  2499   * Returns
  2500   * 	Number of character copied (not including the trailing NUL).
  2501   *
  2502   * 	**-E2BIG** if the buffer wasn't big enough (*buf* will contain
  2503   * 	truncated name in this case).
  2504   *
  2505   * 	**-EINVAL** if current value was unavailable, e.g. because
  2506   * 	sysctl is uninitialized and read returns -EIO for it.
  2507   */
  2508  static long (*bpf_sysctl_get_current_value)(struct bpf_sysctl *ctx, char *buf, unsigned long buf_len) = (void *) 102;
  2509  
  2510  /*
  2511   * bpf_sysctl_get_new_value
  2512   *
  2513   * 	Get new value being written by user space to sysctl (before
  2514   * 	the actual write happens) and copy it as a string into
  2515   * 	provided by program buffer *buf* of size *buf_len*.
  2516   *
  2517   * 	User space may write new value at file position > 0.
  2518   *
  2519   * 	The buffer is always NUL terminated, unless it's zero-sized.
  2520   *
  2521   * Returns
  2522   * 	Number of character copied (not including the trailing NUL).
  2523   *
  2524   * 	**-E2BIG** if the buffer wasn't big enough (*buf* will contain
  2525   * 	truncated name in this case).
  2526   *
  2527   * 	**-EINVAL** if sysctl is being read.
  2528   */
  2529  static long (*bpf_sysctl_get_new_value)(struct bpf_sysctl *ctx, char *buf, unsigned long buf_len) = (void *) 103;
  2530  
  2531  /*
  2532   * bpf_sysctl_set_new_value
  2533   *
  2534   * 	Override new value being written by user space to sysctl with
  2535   * 	value provided by program in buffer *buf* of size *buf_len*.
  2536   *
  2537   * 	*buf* should contain a string in same form as provided by user
  2538   * 	space on sysctl write.
  2539   *
  2540   * 	User space may write new value at file position > 0. To override
  2541   * 	the whole sysctl value file position should be set to zero.
  2542   *
  2543   * Returns
  2544   * 	0 on success.
  2545   *
  2546   * 	**-E2BIG** if the *buf_len* is too big.
  2547   *
  2548   * 	**-EINVAL** if sysctl is being read.
  2549   */
  2550  static long (*bpf_sysctl_set_new_value)(struct bpf_sysctl *ctx, const char *buf, unsigned long buf_len) = (void *) 104;
  2551  
  2552  /*
  2553   * bpf_strtol
  2554   *
  2555   * 	Convert the initial part of the string from buffer *buf* of
  2556   * 	size *buf_len* to a long integer according to the given base
  2557   * 	and save the result in *res*.
  2558   *
  2559   * 	The string may begin with an arbitrary amount of white space
  2560   * 	(as determined by **isspace**\ (3)) followed by a single
  2561   * 	optional '**-**' sign.
  2562   *
  2563   * 	Five least significant bits of *flags* encode base, other bits
  2564   * 	are currently unused.
  2565   *
  2566   * 	Base must be either 8, 10, 16 or 0 to detect it automatically
  2567   * 	similar to user space **strtol**\ (3).
  2568   *
  2569   * Returns
  2570   * 	Number of characters consumed on success. Must be positive but
  2571   * 	no more than *buf_len*.
  2572   *
  2573   * 	**-EINVAL** if no valid digits were found or unsupported base
  2574   * 	was provided.
  2575   *
  2576   * 	**-ERANGE** if resulting value was out of range.
  2577   */
  2578  static long (*bpf_strtol)(const char *buf, unsigned long buf_len, __u64 flags, long *res) = (void *) 105;
  2579  
  2580  /*
  2581   * bpf_strtoul
  2582   *
  2583   * 	Convert the initial part of the string from buffer *buf* of
  2584   * 	size *buf_len* to an unsigned long integer according to the
  2585   * 	given base and save the result in *res*.
  2586   *
  2587   * 	The string may begin with an arbitrary amount of white space
  2588   * 	(as determined by **isspace**\ (3)).
  2589   *
  2590   * 	Five least significant bits of *flags* encode base, other bits
  2591   * 	are currently unused.
  2592   *
  2593   * 	Base must be either 8, 10, 16 or 0 to detect it automatically
  2594   * 	similar to user space **strtoul**\ (3).
  2595   *
  2596   * Returns
  2597   * 	Number of characters consumed on success. Must be positive but
  2598   * 	no more than *buf_len*.
  2599   *
  2600   * 	**-EINVAL** if no valid digits were found or unsupported base
  2601   * 	was provided.
  2602   *
  2603   * 	**-ERANGE** if resulting value was out of range.
  2604   */
  2605  static long (*bpf_strtoul)(const char *buf, unsigned long buf_len, __u64 flags, unsigned long *res) = (void *) 106;
  2606  
  2607  /*
  2608   * bpf_sk_storage_get
  2609   *
  2610   * 	Get a bpf-local-storage from a *sk*.
  2611   *
  2612   * 	Logically, it could be thought of getting the value from
  2613   * 	a *map* with *sk* as the **key**.  From this
  2614   * 	perspective,  the usage is not much different from
  2615   * 	**bpf_map_lookup_elem**\ (*map*, **&**\ *sk*) except this
  2616   * 	helper enforces the key must be a full socket and the map must
  2617   * 	be a **BPF_MAP_TYPE_SK_STORAGE** also.
  2618   *
  2619   * 	Underneath, the value is stored locally at *sk* instead of
  2620   * 	the *map*.  The *map* is used as the bpf-local-storage
  2621   * 	"type". The bpf-local-storage "type" (i.e. the *map*) is
  2622   * 	searched against all bpf-local-storages residing at *sk*.
  2623   *
  2624   * 	*sk* is a kernel **struct sock** pointer for LSM program.
  2625   * 	*sk* is a **struct bpf_sock** pointer for other program types.
  2626   *
  2627   * 	An optional *flags* (**BPF_SK_STORAGE_GET_F_CREATE**) can be
  2628   * 	used such that a new bpf-local-storage will be
  2629   * 	created if one does not exist.  *value* can be used
  2630   * 	together with **BPF_SK_STORAGE_GET_F_CREATE** to specify
  2631   * 	the initial value of a bpf-local-storage.  If *value* is
  2632   * 	**NULL**, the new bpf-local-storage will be zero initialized.
  2633   *
  2634   * Returns
  2635   * 	A bpf-local-storage pointer is returned on success.
  2636   *
  2637   * 	**NULL** if not found or there was an error in adding
  2638   * 	a new bpf-local-storage.
  2639   */
  2640  static void *(*bpf_sk_storage_get)(void *map, void *sk, void *value, __u64 flags) = (void *) 107;
  2641  
  2642  /*
  2643   * bpf_sk_storage_delete
  2644   *
  2645   * 	Delete a bpf-local-storage from a *sk*.
  2646   *
  2647   * Returns
  2648   * 	0 on success.
  2649   *
  2650   * 	**-ENOENT** if the bpf-local-storage cannot be found.
  2651   * 	**-EINVAL** if sk is not a fullsock (e.g. a request_sock).
  2652   */
  2653  static long (*bpf_sk_storage_delete)(void *map, void *sk) = (void *) 108;
  2654  
  2655  /*
  2656   * bpf_send_signal
  2657   *
  2658   * 	Send signal *sig* to the process of the current task.
  2659   * 	The signal may be delivered to any of this process's threads.
  2660   *
  2661   * Returns
  2662   * 	0 on success or successfully queued.
  2663   *
  2664   * 	**-EBUSY** if work queue under nmi is full.
  2665   *
  2666   * 	**-EINVAL** if *sig* is invalid.
  2667   *
  2668   * 	**-EPERM** if no permission to send the *sig*.
  2669   *
  2670   * 	**-EAGAIN** if bpf program can try again.
  2671   */
  2672  static long (*bpf_send_signal)(__u32 sig) = (void *) 109;
  2673  
  2674  /*
  2675   * bpf_tcp_gen_syncookie
  2676   *
  2677   * 	Try to issue a SYN cookie for the packet with corresponding
  2678   * 	IP/TCP headers, *iph* and *th*, on the listening socket in *sk*.
  2679   *
  2680   * 	*iph* points to the start of the IPv4 or IPv6 header, while
  2681   * 	*iph_len* contains **sizeof**\ (**struct iphdr**) or
  2682   * 	**sizeof**\ (**struct ip6hdr**).
  2683   *
  2684   * 	*th* points to the start of the TCP header, while *th_len*
  2685   * 	contains the length of the TCP header.
  2686   *
  2687   * Returns
  2688   * 	On success, lower 32 bits hold the generated SYN cookie in
  2689   * 	followed by 16 bits which hold the MSS value for that cookie,
  2690   * 	and the top 16 bits are unused.
  2691   *
  2692   * 	On failure, the returned value is one of the following:
  2693   *
  2694   * 	**-EINVAL** SYN cookie cannot be issued due to error
  2695   *
  2696   * 	**-ENOENT** SYN cookie should not be issued (no SYN flood)
  2697   *
  2698   * 	**-EOPNOTSUPP** kernel configuration does not enable SYN cookies
  2699   *
  2700   * 	**-EPROTONOSUPPORT** IP packet version is not 4 or 6
  2701   */
  2702  static __s64 (*bpf_tcp_gen_syncookie)(void *sk, void *iph, __u32 iph_len, struct tcphdr *th, __u32 th_len) = (void *) 110;
  2703  
  2704  /*
  2705   * bpf_skb_output
  2706   *
  2707   * 	Write raw *data* blob into a special BPF perf event held by
  2708   * 	*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
  2709   * 	event must have the following attributes: **PERF_SAMPLE_RAW**
  2710   * 	as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
  2711   * 	**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
  2712   *
  2713   * 	The *flags* are used to indicate the index in *map* for which
  2714   * 	the value must be put, masked with **BPF_F_INDEX_MASK**.
  2715   * 	Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
  2716   * 	to indicate that the index of the current CPU core should be
  2717   * 	used.
  2718   *
  2719   * 	The value to write, of *size*, is passed through eBPF stack and
  2720   * 	pointed by *data*.
  2721   *
  2722   * 	*ctx* is a pointer to in-kernel struct sk_buff.
  2723   *
  2724   * 	This helper is similar to **bpf_perf_event_output**\ () but
  2725   * 	restricted to raw_tracepoint bpf programs.
  2726   *
  2727   * Returns
  2728   * 	0 on success, or a negative error in case of failure.
  2729   */
  2730  static long (*bpf_skb_output)(void *ctx, void *map, __u64 flags, void *data, __u64 size) = (void *) 111;
  2731  
  2732  /*
  2733   * bpf_probe_read_user
  2734   *
  2735   * 	Safely attempt to read *size* bytes from user space address
  2736   * 	*unsafe_ptr* and store the data in *dst*.
  2737   *
  2738   * Returns
  2739   * 	0 on success, or a negative error in case of failure.
  2740   */
  2741  static long (*bpf_probe_read_user)(void *dst, __u32 size, const void *unsafe_ptr) = (void *) 112;
  2742  
  2743  /*
  2744   * bpf_probe_read_kernel
  2745   *
  2746   * 	Safely attempt to read *size* bytes from kernel space address
  2747   * 	*unsafe_ptr* and store the data in *dst*.
  2748   *
  2749   * Returns
  2750   * 	0 on success, or a negative error in case of failure.
  2751   */
  2752  static long (*bpf_probe_read_kernel)(void *dst, __u32 size, const void *unsafe_ptr) = (void *) 113;
  2753  
  2754  /*
  2755   * bpf_probe_read_user_str
  2756   *
  2757   * 	Copy a NUL terminated string from an unsafe user address
  2758   * 	*unsafe_ptr* to *dst*. The *size* should include the
  2759   * 	terminating NUL byte. In case the string length is smaller than
  2760   * 	*size*, the target is not padded with further NUL bytes. If the
  2761   * 	string length is larger than *size*, just *size*-1 bytes are
  2762   * 	copied and the last byte is set to NUL.
  2763   *
  2764   * 	On success, returns the number of bytes that were written,
  2765   * 	including the terminal NUL. This makes this helper useful in
  2766   * 	tracing programs for reading strings, and more importantly to
  2767   * 	get its length at runtime. See the following snippet:
  2768   *
  2769   * 	::
  2770   *
  2771   * 		SEC("kprobe/sys_open")
  2772   * 		void bpf_sys_open(struct pt_regs *ctx)
  2773   * 		{
  2774   * 		        char buf[PATHLEN]; // PATHLEN is defined to 256
  2775   * 		        int res = bpf_probe_read_user_str(buf, sizeof(buf),
  2776   * 			                                  ctx->di);
  2777   *
  2778   * 			// Consume buf, for example push it to
  2779   * 			// userspace via bpf_perf_event_output(); we
  2780   * 			// can use res (the string length) as event
  2781   * 			// size, after checking its boundaries.
  2782   * 		}
  2783   *
  2784   * 	In comparison, using **bpf_probe_read_user**\ () helper here
  2785   * 	instead to read the string would require to estimate the length
  2786   * 	at compile time, and would often result in copying more memory
  2787   * 	than necessary.
  2788   *
  2789   * 	Another useful use case is when parsing individual process
  2790   * 	arguments or individual environment variables navigating
  2791   * 	*current*\ **->mm->arg_start** and *current*\
  2792   * 	**->mm->env_start**: using this helper and the return value,
  2793   * 	one can quickly iterate at the right offset of the memory area.
  2794   *
  2795   * Returns
  2796   * 	On success, the strictly positive length of the output string,
  2797   * 	including the trailing NUL character. On error, a negative
  2798   * 	value.
  2799   */
  2800  static long (*bpf_probe_read_user_str)(void *dst, __u32 size, const void *unsafe_ptr) = (void *) 114;
  2801  
  2802  /*
  2803   * bpf_probe_read_kernel_str
  2804   *
  2805   * 	Copy a NUL terminated string from an unsafe kernel address *unsafe_ptr*
  2806   * 	to *dst*. Same semantics as with **bpf_probe_read_user_str**\ () apply.
  2807   *
  2808   * Returns
  2809   * 	On success, the strictly positive length of the string, including
  2810   * 	the trailing NUL character. On error, a negative value.
  2811   */
  2812  static long (*bpf_probe_read_kernel_str)(void *dst, __u32 size, const void *unsafe_ptr) = (void *) 115;
  2813  
  2814  /*
  2815   * bpf_tcp_send_ack
  2816   *
  2817   * 	Send out a tcp-ack. *tp* is the in-kernel struct **tcp_sock**.
  2818   * 	*rcv_nxt* is the ack_seq to be sent out.
  2819   *
  2820   * Returns
  2821   * 	0 on success, or a negative error in case of failure.
  2822   */
  2823  static long (*bpf_tcp_send_ack)(void *tp, __u32 rcv_nxt) = (void *) 116;
  2824  
  2825  /*
  2826   * bpf_send_signal_thread
  2827   *
  2828   * 	Send signal *sig* to the thread corresponding to the current task.
  2829   *
  2830   * Returns
  2831   * 	0 on success or successfully queued.
  2832   *
  2833   * 	**-EBUSY** if work queue under nmi is full.
  2834   *
  2835   * 	**-EINVAL** if *sig* is invalid.
  2836   *
  2837   * 	**-EPERM** if no permission to send the *sig*.
  2838   *
  2839   * 	**-EAGAIN** if bpf program can try again.
  2840   */
  2841  static long (*bpf_send_signal_thread)(__u32 sig) = (void *) 117;
  2842  
  2843  /*
  2844   * bpf_jiffies64
  2845   *
  2846   * 	Obtain the 64bit jiffies
  2847   *
  2848   * Returns
  2849   * 	The 64 bit jiffies
  2850   */
  2851  static __u64 (*bpf_jiffies64)(void) = (void *) 118;
  2852  
  2853  /*
  2854   * bpf_read_branch_records
  2855   *
  2856   * 	For an eBPF program attached to a perf event, retrieve the
  2857   * 	branch records (**struct perf_branch_entry**) associated to *ctx*
  2858   * 	and store it in the buffer pointed by *buf* up to size
  2859   * 	*size* bytes.
  2860   *
  2861   * Returns
  2862   * 	On success, number of bytes written to *buf*. On error, a
  2863   * 	negative value.
  2864   *
  2865   * 	The *flags* can be set to **BPF_F_GET_BRANCH_RECORDS_SIZE** to
  2866   * 	instead return the number of bytes required to store all the
  2867   * 	branch entries. If this flag is set, *buf* may be NULL.
  2868   *
  2869   * 	**-EINVAL** if arguments invalid or **size** not a multiple
  2870   * 	of **sizeof**\ (**struct perf_branch_entry**\ ).
  2871   *
  2872   * 	**-ENOENT** if architecture does not support branch records.
  2873   */
  2874  static long (*bpf_read_branch_records)(struct bpf_perf_event_data *ctx, void *buf, __u32 size, __u64 flags) = (void *) 119;
  2875  
  2876  /*
  2877   * bpf_get_ns_current_pid_tgid
  2878   *
  2879   * 	Returns 0 on success, values for *pid* and *tgid* as seen from the current
  2880   * 	*namespace* will be returned in *nsdata*.
  2881   *
  2882   * Returns
  2883   * 	0 on success, or one of the following in case of failure:
  2884   *
  2885   * 	**-EINVAL** if dev and inum supplied don't match dev_t and inode number
  2886   * 	with nsfs of current task, or if dev conversion to dev_t lost high bits.
  2887   *
  2888   * 	**-ENOENT** if pidns does not exists for the current task.
  2889   */
  2890  static long (*bpf_get_ns_current_pid_tgid)(__u64 dev, __u64 ino, struct bpf_pidns_info *nsdata, __u32 size) = (void *) 120;
  2891  
  2892  /*
  2893   * bpf_xdp_output
  2894   *
  2895   * 	Write raw *data* blob into a special BPF perf event held by
  2896   * 	*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
  2897   * 	event must have the following attributes: **PERF_SAMPLE_RAW**
  2898   * 	as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
  2899   * 	**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
  2900   *
  2901   * 	The *flags* are used to indicate the index in *map* for which
  2902   * 	the value must be put, masked with **BPF_F_INDEX_MASK**.
  2903   * 	Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
  2904   * 	to indicate that the index of the current CPU core should be
  2905   * 	used.
  2906   *
  2907   * 	The value to write, of *size*, is passed through eBPF stack and
  2908   * 	pointed by *data*.
  2909   *
  2910   * 	*ctx* is a pointer to in-kernel struct xdp_buff.
  2911   *
  2912   * 	This helper is similar to **bpf_perf_eventoutput**\ () but
  2913   * 	restricted to raw_tracepoint bpf programs.
  2914   *
  2915   * Returns
  2916   * 	0 on success, or a negative error in case of failure.
  2917   */
  2918  static long (*bpf_xdp_output)(void *ctx, void *map, __u64 flags, void *data, __u64 size) = (void *) 121;
  2919  
  2920  /*
  2921   * bpf_get_netns_cookie
  2922   *
  2923   * 	Retrieve the cookie (generated by the kernel) of the network
  2924   * 	namespace the input *ctx* is associated with. The network
  2925   * 	namespace cookie remains stable for its lifetime and provides
  2926   * 	a global identifier that can be assumed unique. If *ctx* is
  2927   * 	NULL, then the helper returns the cookie for the initial
  2928   * 	network namespace. The cookie itself is very similar to that
  2929   * 	of **bpf_get_socket_cookie**\ () helper, but for network
  2930   * 	namespaces instead of sockets.
  2931   *
  2932   * Returns
  2933   * 	A 8-byte long opaque number.
  2934   */
  2935  static __u64 (*bpf_get_netns_cookie)(void *ctx) = (void *) 122;
  2936  
  2937  /*
  2938   * bpf_get_current_ancestor_cgroup_id
  2939   *
  2940   * 	Return id of cgroup v2 that is ancestor of the cgroup associated
  2941   * 	with the current task at the *ancestor_level*. The root cgroup
  2942   * 	is at *ancestor_level* zero and each step down the hierarchy
  2943   * 	increments the level. If *ancestor_level* == level of cgroup
  2944   * 	associated with the current task, then return value will be the
  2945   * 	same as that of **bpf_get_current_cgroup_id**\ ().
  2946   *
  2947   * 	The helper is useful to implement policies based on cgroups
  2948   * 	that are upper in hierarchy than immediate cgroup associated
  2949   * 	with the current task.
  2950   *
  2951   * 	The format of returned id and helper limitations are same as in
  2952   * 	**bpf_get_current_cgroup_id**\ ().
  2953   *
  2954   * Returns
  2955   * 	The id is returned or 0 in case the id could not be retrieved.
  2956   */
  2957  static __u64 (*bpf_get_current_ancestor_cgroup_id)(int ancestor_level) = (void *) 123;
  2958  
  2959  /*
  2960   * bpf_sk_assign
  2961   *
  2962   * 	Helper is overloaded depending on BPF program type. This
  2963   * 	description applies to **BPF_PROG_TYPE_SCHED_CLS** and
  2964   * 	**BPF_PROG_TYPE_SCHED_ACT** programs.
  2965   *
  2966   * 	Assign the *sk* to the *skb*. When combined with appropriate
  2967   * 	routing configuration to receive the packet towards the socket,
  2968   * 	will cause *skb* to be delivered to the specified socket.
  2969   * 	Subsequent redirection of *skb* via  **bpf_redirect**\ (),
  2970   * 	**bpf_clone_redirect**\ () or other methods outside of BPF may
  2971   * 	interfere with successful delivery to the socket.
  2972   *
  2973   * 	This operation is only valid from TC ingress path.
  2974   *
  2975   * 	The *flags* argument must be zero.
  2976   *
  2977   * Returns
  2978   * 	0 on success, or a negative error in case of failure:
  2979   *
  2980   * 	**-EINVAL** if specified *flags* are not supported.
  2981   *
  2982   * 	**-ENOENT** if the socket is unavailable for assignment.
  2983   *
  2984   * 	**-ENETUNREACH** if the socket is unreachable (wrong netns).
  2985   *
  2986   * 	**-EOPNOTSUPP** if the operation is not supported, for example
  2987   * 	a call from outside of TC ingress.
  2988   *
  2989   * 	**-ESOCKTNOSUPPORT** if the socket type is not supported
  2990   * 	(reuseport).
  2991   */
  2992  static long (*bpf_sk_assign)(void *ctx, void *sk, __u64 flags) = (void *) 124;
  2993  
  2994  /*
  2995   * bpf_ktime_get_boot_ns
  2996   *
  2997   * 	Return the time elapsed since system boot, in nanoseconds.
  2998   * 	Does include the time the system was suspended.
  2999   * 	See: **clock_gettime**\ (**CLOCK_BOOTTIME**)
  3000   *
  3001   * Returns
  3002   * 	Current *ktime*.
  3003   */
  3004  static __u64 (*bpf_ktime_get_boot_ns)(void) = (void *) 125;
  3005  
  3006  /*
  3007   * bpf_seq_printf
  3008   *
  3009   * 	**bpf_seq_printf**\ () uses seq_file **seq_printf**\ () to print
  3010   * 	out the format string.
  3011   * 	The *m* represents the seq_file. The *fmt* and *fmt_size* are for
  3012   * 	the format string itself. The *data* and *data_len* are format string
  3013   * 	arguments. The *data* are a **u64** array and corresponding format string
  3014   * 	values are stored in the array. For strings and pointers where pointees
  3015   * 	are accessed, only the pointer values are stored in the *data* array.
  3016   * 	The *data_len* is the size of *data* in bytes - must be a multiple of 8.
  3017   *
  3018   * 	Formats **%s**, **%p{i,I}{4,6}** requires to read kernel memory.
  3019   * 	Reading kernel memory may fail due to either invalid address or
  3020   * 	valid address but requiring a major memory fault. If reading kernel memory
  3021   * 	fails, the string for **%s** will be an empty string, and the ip
  3022   * 	address for **%p{i,I}{4,6}** will be 0. Not returning error to
  3023   * 	bpf program is consistent with what **bpf_trace_printk**\ () does for now.
  3024   *
  3025   * Returns
  3026   * 	0 on success, or a negative error in case of failure:
  3027   *
  3028   * 	**-EBUSY** if per-CPU memory copy buffer is busy, can try again
  3029   * 	by returning 1 from bpf program.
  3030   *
  3031   * 	**-EINVAL** if arguments are invalid, or if *fmt* is invalid/unsupported.
  3032   *
  3033   * 	**-E2BIG** if *fmt* contains too many format specifiers.
  3034   *
  3035   * 	**-EOVERFLOW** if an overflow happened: The same object will be tried again.
  3036   */
  3037  static long (*bpf_seq_printf)(struct seq_file *m, const char *fmt, __u32 fmt_size, const void *data, __u32 data_len) = (void *) 126;
  3038  
  3039  /*
  3040   * bpf_seq_write
  3041   *
  3042   * 	**bpf_seq_write**\ () uses seq_file **seq_write**\ () to write the data.
  3043   * 	The *m* represents the seq_file. The *data* and *len* represent the
  3044   * 	data to write in bytes.
  3045   *
  3046   * Returns
  3047   * 	0 on success, or a negative error in case of failure:
  3048   *
  3049   * 	**-EOVERFLOW** if an overflow happened: The same object will be tried again.
  3050   */
  3051  static long (*bpf_seq_write)(struct seq_file *m, const void *data, __u32 len) = (void *) 127;
  3052  
  3053  /*
  3054   * bpf_sk_cgroup_id
  3055   *
  3056   * 	Return the cgroup v2 id of the socket *sk*.
  3057   *
  3058   * 	*sk* must be a non-**NULL** pointer to a socket, e.g. one
  3059   * 	returned from **bpf_sk_lookup_xxx**\ (),
  3060   * 	**bpf_sk_fullsock**\ (), etc. The format of returned id is
  3061   * 	same as in **bpf_skb_cgroup_id**\ ().
  3062   *
  3063   * 	This helper is available only if the kernel was compiled with
  3064   * 	the **CONFIG_SOCK_CGROUP_DATA** configuration option.
  3065   *
  3066   * Returns
  3067   * 	The id is returned or 0 in case the id could not be retrieved.
  3068   */
  3069  static __u64 (*bpf_sk_cgroup_id)(void *sk) = (void *) 128;
  3070  
  3071  /*
  3072   * bpf_sk_ancestor_cgroup_id
  3073   *
  3074   * 	Return id of cgroup v2 that is ancestor of cgroup associated
  3075   * 	with the *sk* at the *ancestor_level*.  The root cgroup is at
  3076   * 	*ancestor_level* zero and each step down the hierarchy
  3077   * 	increments the level. If *ancestor_level* == level of cgroup
  3078   * 	associated with *sk*, then return value will be same as that
  3079   * 	of **bpf_sk_cgroup_id**\ ().
  3080   *
  3081   * 	The helper is useful to implement policies based on cgroups
  3082   * 	that are upper in hierarchy than immediate cgroup associated
  3083   * 	with *sk*.
  3084   *
  3085   * 	The format of returned id and helper limitations are same as in
  3086   * 	**bpf_sk_cgroup_id**\ ().
  3087   *
  3088   * Returns
  3089   * 	The id is returned or 0 in case the id could not be retrieved.
  3090   */
  3091  static __u64 (*bpf_sk_ancestor_cgroup_id)(void *sk, int ancestor_level) = (void *) 129;
  3092  
  3093  /*
  3094   * bpf_ringbuf_output
  3095   *
  3096   * 	Copy *size* bytes from *data* into a ring buffer *ringbuf*.
  3097   * 	If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
  3098   * 	of new data availability is sent.
  3099   * 	If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
  3100   * 	of new data availability is sent unconditionally.
  3101   * 	If **0** is specified in *flags*, an adaptive notification
  3102   * 	of new data availability is sent.
  3103   *
  3104   * 	An adaptive notification is a notification sent whenever the user-space
  3105   * 	process has caught up and consumed all available payloads. In case the user-space
  3106   * 	process is still processing a previous payload, then no notification is needed
  3107   * 	as it will process the newly added payload automatically.
  3108   *
  3109   * Returns
  3110   * 	0 on success, or a negative error in case of failure.
  3111   */
  3112  static long (*bpf_ringbuf_output)(void *ringbuf, void *data, __u64 size, __u64 flags) = (void *) 130;
  3113  
  3114  /*
  3115   * bpf_ringbuf_reserve
  3116   *
  3117   * 	Reserve *size* bytes of payload in a ring buffer *ringbuf*.
  3118   * 	*flags* must be 0.
  3119   *
  3120   * Returns
  3121   * 	Valid pointer with *size* bytes of memory available; NULL,
  3122   * 	otherwise.
  3123   */
  3124  static void *(*bpf_ringbuf_reserve)(void *ringbuf, __u64 size, __u64 flags) = (void *) 131;
  3125  
  3126  /*
  3127   * bpf_ringbuf_submit
  3128   *
  3129   * 	Submit reserved ring buffer sample, pointed to by *data*.
  3130   * 	If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
  3131   * 	of new data availability is sent.
  3132   * 	If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
  3133   * 	of new data availability is sent unconditionally.
  3134   * 	If **0** is specified in *flags*, an adaptive notification
  3135   * 	of new data availability is sent.
  3136   *
  3137   * 	See 'bpf_ringbuf_output()' for the definition of adaptive notification.
  3138   *
  3139   * Returns
  3140   * 	Nothing. Always succeeds.
  3141   */
  3142  static void (*bpf_ringbuf_submit)(void *data, __u64 flags) = (void *) 132;
  3143  
  3144  /*
  3145   * bpf_ringbuf_discard
  3146   *
  3147   * 	Discard reserved ring buffer sample, pointed to by *data*.
  3148   * 	If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
  3149   * 	of new data availability is sent.
  3150   * 	If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
  3151   * 	of new data availability is sent unconditionally.
  3152   * 	If **0** is specified in *flags*, an adaptive notification
  3153   * 	of new data availability is sent.
  3154   *
  3155   * 	See 'bpf_ringbuf_output()' for the definition of adaptive notification.
  3156   *
  3157   * Returns
  3158   * 	Nothing. Always succeeds.
  3159   */
  3160  static void (*bpf_ringbuf_discard)(void *data, __u64 flags) = (void *) 133;
  3161  
  3162  /*
  3163   * bpf_ringbuf_query
  3164   *
  3165   * 	Query various characteristics of provided ring buffer. What
  3166   * 	exactly is queries is determined by *flags*:
  3167   *
  3168   * 	* **BPF_RB_AVAIL_DATA**: Amount of data not yet consumed.
  3169   * 	* **BPF_RB_RING_SIZE**: The size of ring buffer.
  3170   * 	* **BPF_RB_CONS_POS**: Consumer position (can wrap around).
  3171   * 	* **BPF_RB_PROD_POS**: Producer(s) position (can wrap around).
  3172   *
  3173   * 	Data returned is just a momentary snapshot of actual values
  3174   * 	and could be inaccurate, so this facility should be used to
  3175   * 	power heuristics and for reporting, not to make 100% correct
  3176   * 	calculation.
  3177   *
  3178   * Returns
  3179   * 	Requested value, or 0, if *flags* are not recognized.
  3180   */
  3181  static __u64 (*bpf_ringbuf_query)(void *ringbuf, __u64 flags) = (void *) 134;
  3182  
  3183  /*
  3184   * bpf_csum_level
  3185   *
  3186   * 	Change the skbs checksum level by one layer up or down, or
  3187   * 	reset it entirely to none in order to have the stack perform
  3188   * 	checksum validation. The level is applicable to the following
  3189   * 	protocols: TCP, UDP, GRE, SCTP, FCOE. For example, a decap of
  3190   * 	| ETH | IP | UDP | GUE | IP | TCP | into | ETH | IP | TCP |
  3191   * 	through **bpf_skb_adjust_room**\ () helper with passing in
  3192   * 	**BPF_F_ADJ_ROOM_NO_CSUM_RESET** flag would require one	call
  3193   * 	to **bpf_csum_level**\ () with **BPF_CSUM_LEVEL_DEC** since
  3194   * 	the UDP header is removed. Similarly, an encap of the latter
  3195   * 	into the former could be accompanied by a helper call to
  3196   * 	**bpf_csum_level**\ () with **BPF_CSUM_LEVEL_INC** if the
  3197   * 	skb is still intended to be processed in higher layers of the
  3198   * 	stack instead of just egressing at tc.
  3199   *
  3200   * 	There are three supported level settings at this time:
  3201   *
  3202   * 	* **BPF_CSUM_LEVEL_INC**: Increases skb->csum_level for skbs
  3203   * 	  with CHECKSUM_UNNECESSARY.
  3204   * 	* **BPF_CSUM_LEVEL_DEC**: Decreases skb->csum_level for skbs
  3205   * 	  with CHECKSUM_UNNECESSARY.
  3206   * 	* **BPF_CSUM_LEVEL_RESET**: Resets skb->csum_level to 0 and
  3207   * 	  sets CHECKSUM_NONE to force checksum validation by the stack.
  3208   * 	* **BPF_CSUM_LEVEL_QUERY**: No-op, returns the current
  3209   * 	  skb->csum_level.
  3210   *
  3211   * Returns
  3212   * 	0 on success, or a negative error in case of failure. In the
  3213   * 	case of **BPF_CSUM_LEVEL_QUERY**, the current skb->csum_level
  3214   * 	is returned or the error code -EACCES in case the skb is not
  3215   * 	subject to CHECKSUM_UNNECESSARY.
  3216   */
  3217  static long (*bpf_csum_level)(struct __sk_buff *skb, __u64 level) = (void *) 135;
  3218  
  3219  /*
  3220   * bpf_skc_to_tcp6_sock
  3221   *
  3222   * 	Dynamically cast a *sk* pointer to a *tcp6_sock* pointer.
  3223   *
  3224   * Returns
  3225   * 	*sk* if casting is valid, or **NULL** otherwise.
  3226   */
  3227  static struct tcp6_sock *(*bpf_skc_to_tcp6_sock)(void *sk) = (void *) 136;
  3228  
  3229  /*
  3230   * bpf_skc_to_tcp_sock
  3231   *
  3232   * 	Dynamically cast a *sk* pointer to a *tcp_sock* pointer.
  3233   *
  3234   * Returns
  3235   * 	*sk* if casting is valid, or **NULL** otherwise.
  3236   */
  3237  static struct tcp_sock *(*bpf_skc_to_tcp_sock)(void *sk) = (void *) 137;
  3238  
  3239  /*
  3240   * bpf_skc_to_tcp_timewait_sock
  3241   *
  3242   * 	Dynamically cast a *sk* pointer to a *tcp_timewait_sock* pointer.
  3243   *
  3244   * Returns
  3245   * 	*sk* if casting is valid, or **NULL** otherwise.
  3246   */
  3247  static struct tcp_timewait_sock *(*bpf_skc_to_tcp_timewait_sock)(void *sk) = (void *) 138;
  3248  
  3249  /*
  3250   * bpf_skc_to_tcp_request_sock
  3251   *
  3252   * 	Dynamically cast a *sk* pointer to a *tcp_request_sock* pointer.
  3253   *
  3254   * Returns
  3255   * 	*sk* if casting is valid, or **NULL** otherwise.
  3256   */
  3257  static struct tcp_request_sock *(*bpf_skc_to_tcp_request_sock)(void *sk) = (void *) 139;
  3258  
  3259  /*
  3260   * bpf_skc_to_udp6_sock
  3261   *
  3262   * 	Dynamically cast a *sk* pointer to a *udp6_sock* pointer.
  3263   *
  3264   * Returns
  3265   * 	*sk* if casting is valid, or **NULL** otherwise.
  3266   */
  3267  static struct udp6_sock *(*bpf_skc_to_udp6_sock)(void *sk) = (void *) 140;
  3268  
  3269  /*
  3270   * bpf_get_task_stack
  3271   *
  3272   * 	Return a user or a kernel stack in bpf program provided buffer.
  3273   * 	To achieve this, the helper needs *task*, which is a valid
  3274   * 	pointer to **struct task_struct**. To store the stacktrace, the
  3275   * 	bpf program provides *buf* with a nonnegative *size*.
  3276   *
  3277   * 	The last argument, *flags*, holds the number of stack frames to
  3278   * 	skip (from 0 to 255), masked with
  3279   * 	**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
  3280   * 	the following flags:
  3281   *
  3282   * 	**BPF_F_USER_STACK**
  3283   * 		Collect a user space stack instead of a kernel stack.
  3284   * 	**BPF_F_USER_BUILD_ID**
  3285   * 		Collect buildid+offset instead of ips for user stack,
  3286   * 		only valid if **BPF_F_USER_STACK** is also specified.
  3287   *
  3288   * 	**bpf_get_task_stack**\ () can collect up to
  3289   * 	**PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
  3290   * 	to sufficient large buffer size. Note that
  3291   * 	this limit can be controlled with the **sysctl** program, and
  3292   * 	that it should be manually increased in order to profile long
  3293   * 	user stacks (such as stacks for Java programs). To do so, use:
  3294   *
  3295   * 	::
  3296   *
  3297   * 		# sysctl kernel.perf_event_max_stack=<new value>
  3298   *
  3299   * Returns
  3300   * 	A non-negative value equal to or less than *size* on success,
  3301   * 	or a negative error in case of failure.
  3302   */
  3303  static long (*bpf_get_task_stack)(struct task_struct *task, void *buf, __u32 size, __u64 flags) = (void *) 141;
  3304  
  3305  /*
  3306   * bpf_load_hdr_opt
  3307   *
  3308   * 	Load header option.  Support reading a particular TCP header
  3309   * 	option for bpf program (**BPF_PROG_TYPE_SOCK_OPS**).
  3310   *
  3311   * 	If *flags* is 0, it will search the option from the
  3312   * 	*skops*\ **->skb_data**.  The comment in **struct bpf_sock_ops**
  3313   * 	has details on what skb_data contains under different
  3314   * 	*skops*\ **->op**.
  3315   *
  3316   * 	The first byte of the *searchby_res* specifies the
  3317   * 	kind that it wants to search.
  3318   *
  3319   * 	If the searching kind is an experimental kind
  3320   * 	(i.e. 253 or 254 according to RFC6994).  It also
  3321   * 	needs to specify the "magic" which is either
  3322   * 	2 bytes or 4 bytes.  It then also needs to
  3323   * 	specify the size of the magic by using
  3324   * 	the 2nd byte which is "kind-length" of a TCP
  3325   * 	header option and the "kind-length" also
  3326   * 	includes the first 2 bytes "kind" and "kind-length"
  3327   * 	itself as a normal TCP header option also does.
  3328   *
  3329   * 	For example, to search experimental kind 254 with
  3330   * 	2 byte magic 0xeB9F, the searchby_res should be
  3331   * 	[ 254, 4, 0xeB, 0x9F, 0, 0, .... 0 ].
  3332   *
  3333   * 	To search for the standard window scale option (3),
  3334   * 	the *searchby_res* should be [ 3, 0, 0, .... 0 ].
  3335   * 	Note, kind-length must be 0 for regular option.
  3336   *
  3337   * 	Searching for No-Op (0) and End-of-Option-List (1) are
  3338   * 	not supported.
  3339   *
  3340   * 	*len* must be at least 2 bytes which is the minimal size
  3341   * 	of a header option.
  3342   *
  3343   * 	Supported flags:
  3344   *
  3345   * 	* **BPF_LOAD_HDR_OPT_TCP_SYN** to search from the
  3346   * 	  saved_syn packet or the just-received syn packet.
  3347   *
  3348   *
  3349   * Returns
  3350   * 	> 0 when found, the header option is copied to *searchby_res*.
  3351   * 	The return value is the total length copied. On failure, a
  3352   * 	negative error code is returned:
  3353   *
  3354   * 	**-EINVAL** if a parameter is invalid.
  3355   *
  3356   * 	**-ENOMSG** if the option is not found.
  3357   *
  3358   * 	**-ENOENT** if no syn packet is available when
  3359   * 	**BPF_LOAD_HDR_OPT_TCP_SYN** is used.
  3360   *
  3361   * 	**-ENOSPC** if there is not enough space.  Only *len* number of
  3362   * 	bytes are copied.
  3363   *
  3364   * 	**-EFAULT** on failure to parse the header options in the
  3365   * 	packet.
  3366   *
  3367   * 	**-EPERM** if the helper cannot be used under the current
  3368   * 	*skops*\ **->op**.
  3369   */
  3370  static long (*bpf_load_hdr_opt)(struct bpf_sock_ops *skops, void *searchby_res, __u32 len, __u64 flags) = (void *) 142;
  3371  
  3372  /*
  3373   * bpf_store_hdr_opt
  3374   *
  3375   * 	Store header option.  The data will be copied
  3376   * 	from buffer *from* with length *len* to the TCP header.
  3377   *
  3378   * 	The buffer *from* should have the whole option that
  3379   * 	includes the kind, kind-length, and the actual
  3380   * 	option data.  The *len* must be at least kind-length
  3381   * 	long.  The kind-length does not have to be 4 byte
  3382   * 	aligned.  The kernel will take care of the padding
  3383   * 	and setting the 4 bytes aligned value to th->doff.
  3384   *
  3385   * 	This helper will check for duplicated option
  3386   * 	by searching the same option in the outgoing skb.
  3387   *
  3388   * 	This helper can only be called during
  3389   * 	**BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
  3390   *
  3391   *
  3392   * Returns
  3393   * 	0 on success, or negative error in case of failure:
  3394   *
  3395   * 	**-EINVAL** If param is invalid.
  3396   *
  3397   * 	**-ENOSPC** if there is not enough space in the header.
  3398   * 	Nothing has been written
  3399   *
  3400   * 	**-EEXIST** if the option already exists.
  3401   *
  3402   * 	**-EFAULT** on failrue to parse the existing header options.
  3403   *
  3404   * 	**-EPERM** if the helper cannot be used under the current
  3405   * 	*skops*\ **->op**.
  3406   */
  3407  static long (*bpf_store_hdr_opt)(struct bpf_sock_ops *skops, const void *from, __u32 len, __u64 flags) = (void *) 143;
  3408  
  3409  /*
  3410   * bpf_reserve_hdr_opt
  3411   *
  3412   * 	Reserve *len* bytes for the bpf header option.  The
  3413   * 	space will be used by **bpf_store_hdr_opt**\ () later in
  3414   * 	**BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
  3415   *
  3416   * 	If **bpf_reserve_hdr_opt**\ () is called multiple times,
  3417   * 	the total number of bytes will be reserved.
  3418   *
  3419   * 	This helper can only be called during
  3420   * 	**BPF_SOCK_OPS_HDR_OPT_LEN_CB**.
  3421   *
  3422   *
  3423   * Returns
  3424   * 	0 on success, or negative error in case of failure:
  3425   *
  3426   * 	**-EINVAL** if a parameter is invalid.
  3427   *
  3428   * 	**-ENOSPC** if there is not enough space in the header.
  3429   *
  3430   * 	**-EPERM** if the helper cannot be used under the current
  3431   * 	*skops*\ **->op**.
  3432   */
  3433  static long (*bpf_reserve_hdr_opt)(struct bpf_sock_ops *skops, __u32 len, __u64 flags) = (void *) 144;
  3434  
  3435  /*
  3436   * bpf_inode_storage_get
  3437   *
  3438   * 	Get a bpf_local_storage from an *inode*.
  3439   *
  3440   * 	Logically, it could be thought of as getting the value from
  3441   * 	a *map* with *inode* as the **key**.  From this
  3442   * 	perspective,  the usage is not much different from
  3443   * 	**bpf_map_lookup_elem**\ (*map*, **&**\ *inode*) except this
  3444   * 	helper enforces the key must be an inode and the map must also
  3445   * 	be a **BPF_MAP_TYPE_INODE_STORAGE**.
  3446   *
  3447   * 	Underneath, the value is stored locally at *inode* instead of
  3448   * 	the *map*.  The *map* is used as the bpf-local-storage
  3449   * 	"type". The bpf-local-storage "type" (i.e. the *map*) is
  3450   * 	searched against all bpf_local_storage residing at *inode*.
  3451   *
  3452   * 	An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
  3453   * 	used such that a new bpf_local_storage will be
  3454   * 	created if one does not exist.  *value* can be used
  3455   * 	together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
  3456   * 	the initial value of a bpf_local_storage.  If *value* is
  3457   * 	**NULL**, the new bpf_local_storage will be zero initialized.
  3458   *
  3459   * Returns
  3460   * 	A bpf_local_storage pointer is returned on success.
  3461   *
  3462   * 	**NULL** if not found or there was an error in adding
  3463   * 	a new bpf_local_storage.
  3464   */
  3465  static void *(*bpf_inode_storage_get)(void *map, void *inode, void *value, __u64 flags) = (void *) 145;
  3466  
  3467  /*
  3468   * bpf_inode_storage_delete
  3469   *
  3470   * 	Delete a bpf_local_storage from an *inode*.
  3471   *
  3472   * Returns
  3473   * 	0 on success.
  3474   *
  3475   * 	**-ENOENT** if the bpf_local_storage cannot be found.
  3476   */
  3477  static int (*bpf_inode_storage_delete)(void *map, void *inode) = (void *) 146;
  3478  
  3479  /*
  3480   * bpf_d_path
  3481   *
  3482   * 	Return full path for given **struct path** object, which
  3483   * 	needs to be the kernel BTF *path* object. The path is
  3484   * 	returned in the provided buffer *buf* of size *sz* and
  3485   * 	is zero terminated.
  3486   *
  3487   *
  3488   * Returns
  3489   * 	On success, the strictly positive length of the string,
  3490   * 	including the trailing NUL character. On error, a negative
  3491   * 	value.
  3492   */
  3493  static long (*bpf_d_path)(struct path *path, char *buf, __u32 sz) = (void *) 147;
  3494  
  3495  /*
  3496   * bpf_copy_from_user
  3497   *
  3498   * 	Read *size* bytes from user space address *user_ptr* and store
  3499   * 	the data in *dst*. This is a wrapper of **copy_from_user**\ ().
  3500   *
  3501   * Returns
  3502   * 	0 on success, or a negative error in case of failure.
  3503   */
  3504  static long (*bpf_copy_from_user)(void *dst, __u32 size, const void *user_ptr) = (void *) 148;
  3505  
  3506  /*
  3507   * bpf_snprintf_btf
  3508   *
  3509   * 	Use BTF to store a string representation of *ptr*->ptr in *str*,
  3510   * 	using *ptr*->type_id.  This value should specify the type
  3511   * 	that *ptr*->ptr points to. LLVM __builtin_btf_type_id(type, 1)
  3512   * 	can be used to look up vmlinux BTF type ids. Traversing the
  3513   * 	data structure using BTF, the type information and values are
  3514   * 	stored in the first *str_size* - 1 bytes of *str*.  Safe copy of
  3515   * 	the pointer data is carried out to avoid kernel crashes during
  3516   * 	operation.  Smaller types can use string space on the stack;
  3517   * 	larger programs can use map data to store the string
  3518   * 	representation.
  3519   *
  3520   * 	The string can be subsequently shared with userspace via
  3521   * 	bpf_perf_event_output() or ring buffer interfaces.
  3522   * 	bpf_trace_printk() is to be avoided as it places too small
  3523   * 	a limit on string size to be useful.
  3524   *
  3525   * 	*flags* is a combination of
  3526   *
  3527   * 	**BTF_F_COMPACT**
  3528   * 		no formatting around type information
  3529   * 	**BTF_F_NONAME**
  3530   * 		no struct/union member names/types
  3531   * 	**BTF_F_PTR_RAW**
  3532   * 		show raw (unobfuscated) pointer values;
  3533   * 		equivalent to printk specifier %px.
  3534   * 	**BTF_F_ZERO**
  3535   * 		show zero-valued struct/union members; they
  3536   * 		are not displayed by default
  3537   *
  3538   *
  3539   * Returns
  3540   * 	The number of bytes that were written (or would have been
  3541   * 	written if output had to be truncated due to string size),
  3542   * 	or a negative error in cases of failure.
  3543   */
  3544  static long (*bpf_snprintf_btf)(char *str, __u32 str_size, struct btf_ptr *ptr, __u32 btf_ptr_size, __u64 flags) = (void *) 149;
  3545  
  3546  /*
  3547   * bpf_seq_printf_btf
  3548   *
  3549   * 	Use BTF to write to seq_write a string representation of
  3550   * 	*ptr*->ptr, using *ptr*->type_id as per bpf_snprintf_btf().
  3551   * 	*flags* are identical to those used for bpf_snprintf_btf.
  3552   *
  3553   * Returns
  3554   * 	0 on success or a negative error in case of failure.
  3555   */
  3556  static long (*bpf_seq_printf_btf)(struct seq_file *m, struct btf_ptr *ptr, __u32 ptr_size, __u64 flags) = (void *) 150;
  3557  
  3558  /*
  3559   * bpf_skb_cgroup_classid
  3560   *
  3561   * 	See **bpf_get_cgroup_classid**\ () for the main description.
  3562   * 	This helper differs from **bpf_get_cgroup_classid**\ () in that
  3563   * 	the cgroup v1 net_cls class is retrieved only from the *skb*'s
  3564   * 	associated socket instead of the current process.
  3565   *
  3566   * Returns
  3567   * 	The id is returned or 0 in case the id could not be retrieved.
  3568   */
  3569  static __u64 (*bpf_skb_cgroup_classid)(struct __sk_buff *skb) = (void *) 151;
  3570  
  3571  /*
  3572   * bpf_redirect_neigh
  3573   *
  3574   * 	Redirect the packet to another net device of index *ifindex*
  3575   * 	and fill in L2 addresses from neighboring subsystem. This helper
  3576   * 	is somewhat similar to **bpf_redirect**\ (), except that it
  3577   * 	populates L2 addresses as well, meaning, internally, the helper
  3578   * 	relies on the neighbor lookup for the L2 address of the nexthop.
  3579   *
  3580   * 	The helper will perform a FIB lookup based on the skb's
  3581   * 	networking header to get the address of the next hop, unless
  3582   * 	this is supplied by the caller in the *params* argument. The
  3583   * 	*plen* argument indicates the len of *params* and should be set
  3584   * 	to 0 if *params* is NULL.
  3585   *
  3586   * 	The *flags* argument is reserved and must be 0. The helper is
  3587   * 	currently only supported for tc BPF program types, and enabled
  3588   * 	for IPv4 and IPv6 protocols.
  3589   *
  3590   * Returns
  3591   * 	The helper returns **TC_ACT_REDIRECT** on success or
  3592   * 	**TC_ACT_SHOT** on error.
  3593   */
  3594  static long (*bpf_redirect_neigh)(__u32 ifindex, struct bpf_redir_neigh *params, int plen, __u64 flags) = (void *) 152;
  3595  
  3596  /*
  3597   * bpf_per_cpu_ptr
  3598   *
  3599   * 	Take a pointer to a percpu ksym, *percpu_ptr*, and return a
  3600   * 	pointer to the percpu kernel variable on *cpu*. A ksym is an
  3601   * 	extern variable decorated with '__ksym'. For ksym, there is a
  3602   * 	global var (either static or global) defined of the same name
  3603   * 	in the kernel. The ksym is percpu if the global var is percpu.
  3604   * 	The returned pointer points to the global percpu var on *cpu*.
  3605   *
  3606   * 	bpf_per_cpu_ptr() has the same semantic as per_cpu_ptr() in the
  3607   * 	kernel, except that bpf_per_cpu_ptr() may return NULL. This
  3608   * 	happens if *cpu* is larger than nr_cpu_ids. The caller of
  3609   * 	bpf_per_cpu_ptr() must check the returned value.
  3610   *
  3611   * Returns
  3612   * 	A pointer pointing to the kernel percpu variable on *cpu*, or
  3613   * 	NULL, if *cpu* is invalid.
  3614   */
  3615  static void *(*bpf_per_cpu_ptr)(const void *percpu_ptr, __u32 cpu) = (void *) 153;
  3616  
  3617  /*
  3618   * bpf_this_cpu_ptr
  3619   *
  3620   * 	Take a pointer to a percpu ksym, *percpu_ptr*, and return a
  3621   * 	pointer to the percpu kernel variable on this cpu. See the
  3622   * 	description of 'ksym' in **bpf_per_cpu_ptr**\ ().
  3623   *
  3624   * 	bpf_this_cpu_ptr() has the same semantic as this_cpu_ptr() in
  3625   * 	the kernel. Different from **bpf_per_cpu_ptr**\ (), it would
  3626   * 	never return NULL.
  3627   *
  3628   * Returns
  3629   * 	A pointer pointing to the kernel percpu variable on this cpu.
  3630   */
  3631  static void *(*bpf_this_cpu_ptr)(const void *percpu_ptr) = (void *) 154;
  3632  
  3633  /*
  3634   * bpf_redirect_peer
  3635   *
  3636   * 	Redirect the packet to another net device of index *ifindex*.
  3637   * 	This helper is somewhat similar to **bpf_redirect**\ (), except
  3638   * 	that the redirection happens to the *ifindex*' peer device and
  3639   * 	the netns switch takes place from ingress to ingress without
  3640   * 	going through the CPU's backlog queue.
  3641   *
  3642   * 	The *flags* argument is reserved and must be 0. The helper is
  3643   * 	currently only supported for tc BPF program types at the ingress
  3644   * 	hook and for veth device types. The peer device must reside in a
  3645   * 	different network namespace.
  3646   *
  3647   * Returns
  3648   * 	The helper returns **TC_ACT_REDIRECT** on success or
  3649   * 	**TC_ACT_SHOT** on error.
  3650   */
  3651  static long (*bpf_redirect_peer)(__u32 ifindex, __u64 flags) = (void *) 155;
  3652  
  3653  /*
  3654   * bpf_task_storage_get
  3655   *
  3656   * 	Get a bpf_local_storage from the *task*.
  3657   *
  3658   * 	Logically, it could be thought of as getting the value from
  3659   * 	a *map* with *task* as the **key**.  From this
  3660   * 	perspective,  the usage is not much different from
  3661   * 	**bpf_map_lookup_elem**\ (*map*, **&**\ *task*) except this
  3662   * 	helper enforces the key must be an task_struct and the map must also
  3663   * 	be a **BPF_MAP_TYPE_TASK_STORAGE**.
  3664   *
  3665   * 	Underneath, the value is stored locally at *task* instead of
  3666   * 	the *map*.  The *map* is used as the bpf-local-storage
  3667   * 	"type". The bpf-local-storage "type" (i.e. the *map*) is
  3668   * 	searched against all bpf_local_storage residing at *task*.
  3669   *
  3670   * 	An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
  3671   * 	used such that a new bpf_local_storage will be
  3672   * 	created if one does not exist.  *value* can be used
  3673   * 	together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
  3674   * 	the initial value of a bpf_local_storage.  If *value* is
  3675   * 	**NULL**, the new bpf_local_storage will be zero initialized.
  3676   *
  3677   * Returns
  3678   * 	A bpf_local_storage pointer is returned on success.
  3679   *
  3680   * 	**NULL** if not found or there was an error in adding
  3681   * 	a new bpf_local_storage.
  3682   */
  3683  static void *(*bpf_task_storage_get)(void *map, struct task_struct *task, void *value, __u64 flags) = (void *) 156;
  3684  
  3685  /*
  3686   * bpf_task_storage_delete
  3687   *
  3688   * 	Delete a bpf_local_storage from a *task*.
  3689   *
  3690   * Returns
  3691   * 	0 on success.
  3692   *
  3693   * 	**-ENOENT** if the bpf_local_storage cannot be found.
  3694   */
  3695  static long (*bpf_task_storage_delete)(void *map, struct task_struct *task) = (void *) 157;
  3696  
  3697  /*
  3698   * bpf_get_current_task_btf
  3699   *
  3700   * 	Return a BTF pointer to the "current" task.
  3701   * 	This pointer can also be used in helpers that accept an
  3702   * 	*ARG_PTR_TO_BTF_ID* of type *task_struct*.
  3703   *
  3704   * Returns
  3705   * 	Pointer to the current task.
  3706   */
  3707  static struct task_struct *(*bpf_get_current_task_btf)(void) = (void *) 158;
  3708  
  3709  /*
  3710   * bpf_bprm_opts_set
  3711   *
  3712   * 	Set or clear certain options on *bprm*:
  3713   *
  3714   * 	**BPF_F_BPRM_SECUREEXEC** Set the secureexec bit
  3715   * 	which sets the **AT_SECURE** auxv for glibc. The bit
  3716   * 	is cleared if the flag is not specified.
  3717   *
  3718   * Returns
  3719   * 	**-EINVAL** if invalid *flags* are passed, zero otherwise.
  3720   */
  3721  static long (*bpf_bprm_opts_set)(struct linux_binprm *bprm, __u64 flags) = (void *) 159;
  3722  
  3723  /*
  3724   * bpf_ktime_get_coarse_ns
  3725   *
  3726   * 	Return a coarse-grained version of the time elapsed since
  3727   * 	system boot, in nanoseconds. Does not include time the system
  3728   * 	was suspended.
  3729   *
  3730   * 	See: **clock_gettime**\ (**CLOCK_MONOTONIC_COARSE**)
  3731   *
  3732   * Returns
  3733   * 	Current *ktime*.
  3734   */
  3735  static __u64 (*bpf_ktime_get_coarse_ns)(void) = (void *) 160;
  3736  
  3737  /*
  3738   * bpf_ima_inode_hash
  3739   *
  3740   * 	Returns the stored IMA hash of the *inode* (if it's avaialable).
  3741   * 	If the hash is larger than *size*, then only *size*
  3742   * 	bytes will be copied to *dst*
  3743   *
  3744   * Returns
  3745   * 	The **hash_algo** is returned on success,
  3746   * 	**-EOPNOTSUP** if IMA is disabled or **-EINVAL** if
  3747   * 	invalid arguments are passed.
  3748   */
  3749  static long (*bpf_ima_inode_hash)(struct inode *inode, void *dst, __u32 size) = (void *) 161;
  3750  
  3751  /*
  3752   * bpf_sock_from_file
  3753   *
  3754   * 	If the given file represents a socket, returns the associated
  3755   * 	socket.
  3756   *
  3757   * Returns
  3758   * 	A pointer to a struct socket on success or NULL if the file is
  3759   * 	not a socket.
  3760   */
  3761  static struct socket *(*bpf_sock_from_file)(struct file *file) = (void *) 162;
  3762  
  3763  /*
  3764   * bpf_check_mtu
  3765   *
  3766   * 	Check packet size against exceeding MTU of net device (based
  3767   * 	on *ifindex*).  This helper will likely be used in combination
  3768   * 	with helpers that adjust/change the packet size.
  3769   *
  3770   * 	The argument *len_diff* can be used for querying with a planned
  3771   * 	size change. This allows to check MTU prior to changing packet
  3772   * 	ctx. Providing an *len_diff* adjustment that is larger than the
  3773   * 	actual packet size (resulting in negative packet size) will in
  3774   * 	principle not exceed the MTU, why it is not considered a
  3775   * 	failure.  Other BPF-helpers are needed for performing the
  3776   * 	planned size change, why the responsability for catch a negative
  3777   * 	packet size belong in those helpers.
  3778   *
  3779   * 	Specifying *ifindex* zero means the MTU check is performed
  3780   * 	against the current net device.  This is practical if this isn't
  3781   * 	used prior to redirect.
  3782   *
  3783   * 	On input *mtu_len* must be a valid pointer, else verifier will
  3784   * 	reject BPF program.  If the value *mtu_len* is initialized to
  3785   * 	zero then the ctx packet size is use.  When value *mtu_len* is
  3786   * 	provided as input this specify the L3 length that the MTU check
  3787   * 	is done against. Remember XDP and TC length operate at L2, but
  3788   * 	this value is L3 as this correlate to MTU and IP-header tot_len
  3789   * 	values which are L3 (similar behavior as bpf_fib_lookup).
  3790   *
  3791   * 	The Linux kernel route table can configure MTUs on a more
  3792   * 	specific per route level, which is not provided by this helper.
  3793   * 	For route level MTU checks use the **bpf_fib_lookup**\ ()
  3794   * 	helper.
  3795   *
  3796   * 	*ctx* is either **struct xdp_md** for XDP programs or
  3797   * 	**struct sk_buff** for tc cls_act programs.
  3798   *
  3799   * 	The *flags* argument can be a combination of one or more of the
  3800   * 	following values:
  3801   *
  3802   * 	**BPF_MTU_CHK_SEGS**
  3803   * 		This flag will only works for *ctx* **struct sk_buff**.
  3804   * 		If packet context contains extra packet segment buffers
  3805   * 		(often knows as GSO skb), then MTU check is harder to
  3806   * 		check at this point, because in transmit path it is
  3807   * 		possible for the skb packet to get re-segmented
  3808   * 		(depending on net device features).  This could still be
  3809   * 		a MTU violation, so this flag enables performing MTU
  3810   * 		check against segments, with a different violation
  3811   * 		return code to tell it apart. Check cannot use len_diff.
  3812   *
  3813   * 	On return *mtu_len* pointer contains the MTU value of the net
  3814   * 	device.  Remember the net device configured MTU is the L3 size,
  3815   * 	which is returned here and XDP and TC length operate at L2.
  3816   * 	Helper take this into account for you, but remember when using
  3817   * 	MTU value in your BPF-code.
  3818   *
  3819   *
  3820   * Returns
  3821   * 	* 0 on success, and populate MTU value in *mtu_len* pointer.
  3822   *
  3823   * 	* < 0 if any input argument is invalid (*mtu_len* not updated)
  3824   *
  3825   * 	MTU violations return positive values, but also populate MTU
  3826   * 	value in *mtu_len* pointer, as this can be needed for
  3827   * 	implementing PMTU handing:
  3828   *
  3829   * 	* **BPF_MTU_CHK_RET_FRAG_NEEDED**
  3830   * 	* **BPF_MTU_CHK_RET_SEGS_TOOBIG**
  3831   */
  3832  static long (*bpf_check_mtu)(void *ctx, __u32 ifindex, __u32 *mtu_len, __s32 len_diff, __u64 flags) = (void *) 163;
  3833  
  3834  /*
  3835   * bpf_for_each_map_elem
  3836   *
  3837   * 	For each element in **map**, call **callback_fn** function with
  3838   * 	**map**, **callback_ctx** and other map-specific parameters.
  3839   * 	The **callback_fn** should be a static function and
  3840   * 	the **callback_ctx** should be a pointer to the stack.
  3841   * 	The **flags** is used to control certain aspects of the helper.
  3842   * 	Currently, the **flags** must be 0.
  3843   *
  3844   * 	The following are a list of supported map types and their
  3845   * 	respective expected callback signatures:
  3846   *
  3847   * 	BPF_MAP_TYPE_HASH, BPF_MAP_TYPE_PERCPU_HASH,
  3848   * 	BPF_MAP_TYPE_LRU_HASH, BPF_MAP_TYPE_LRU_PERCPU_HASH,
  3849   * 	BPF_MAP_TYPE_ARRAY, BPF_MAP_TYPE_PERCPU_ARRAY
  3850   *
  3851   * 	long (\*callback_fn)(struct bpf_map \*map, const void \*key, void \*value, void \*ctx);
  3852   *
  3853   * 	For per_cpu maps, the map_value is the value on the cpu where the
  3854   * 	bpf_prog is running.
  3855   *
  3856   * 	If **callback_fn** return 0, the helper will continue to the next
  3857   * 	element. If return value is 1, the helper will skip the rest of
  3858   * 	elements and return. Other return values are not used now.
  3859   *
  3860   *
  3861   * Returns
  3862   * 	The number of traversed map elements for success, **-EINVAL** for
  3863   * 	invalid **flags**.
  3864   */
  3865  static long (*bpf_for_each_map_elem)(void *map, void *callback_fn, void *callback_ctx, __u64 flags) = (void *) 164;
  3866  
  3867  /*
  3868   * bpf_snprintf
  3869   *
  3870   * 	Outputs a string into the **str** buffer of size **str_size**
  3871   * 	based on a format string stored in a read-only map pointed by
  3872   * 	**fmt**.
  3873   *
  3874   * 	Each format specifier in **fmt** corresponds to one u64 element
  3875   * 	in the **data** array. For strings and pointers where pointees
  3876   * 	are accessed, only the pointer values are stored in the *data*
  3877   * 	array. The *data_len* is the size of *data* in bytes - must be
  3878   * 	a multiple of 8.
  3879   *
  3880   * 	Formats **%s** and **%p{i,I}{4,6}** require to read kernel
  3881   * 	memory. Reading kernel memory may fail due to either invalid
  3882   * 	address or valid address but requiring a major memory fault. If
  3883   * 	reading kernel memory fails, the string for **%s** will be an
  3884   * 	empty string, and the ip address for **%p{i,I}{4,6}** will be 0.
  3885   * 	Not returning error to bpf program is consistent with what
  3886   * 	**bpf_trace_printk**\ () does for now.
  3887   *
  3888   *
  3889   * Returns
  3890   * 	The strictly positive length of the formatted string, including
  3891   * 	the trailing zero character. If the return value is greater than
  3892   * 	**str_size**, **str** contains a truncated string, guaranteed to
  3893   * 	be zero-terminated except when **str_size** is 0.
  3894   *
  3895   * 	Or **-EBUSY** if the per-CPU memory copy buffer is busy.
  3896   */
  3897  static long (*bpf_snprintf)(char *str, __u32 str_size, const char *fmt, __u64 *data, __u32 data_len) = (void *) 165;
  3898  
  3899  /*
  3900   * bpf_sys_bpf
  3901   *
  3902   * 	Execute bpf syscall with given arguments.
  3903   *
  3904   * Returns
  3905   * 	A syscall result.
  3906   */
  3907  static long (*bpf_sys_bpf)(__u32 cmd, void *attr, __u32 attr_size) = (void *) 166;
  3908  
  3909  /*
  3910   * bpf_btf_find_by_name_kind
  3911   *
  3912   * 	Find BTF type with given name and kind in vmlinux BTF or in module's BTFs.
  3913   *
  3914   * Returns
  3915   * 	Returns btf_id and btf_obj_fd in lower and upper 32 bits.
  3916   */
  3917  static long (*bpf_btf_find_by_name_kind)(char *name, int name_sz, __u32 kind, int flags) = (void *) 167;
  3918  
  3919  /*
  3920   * bpf_sys_close
  3921   *
  3922   * 	Execute close syscall for given FD.
  3923   *
  3924   * Returns
  3925   * 	A syscall result.
  3926   */
  3927  static long (*bpf_sys_close)(__u32 fd) = (void *) 168;
  3928  
  3929  /*
  3930   * bpf_timer_init
  3931   *
  3932   * 	Initialize the timer.
  3933   * 	First 4 bits of *flags* specify clockid.
  3934   * 	Only CLOCK_MONOTONIC, CLOCK_REALTIME, CLOCK_BOOTTIME are allowed.
  3935   * 	All other bits of *flags* are reserved.
  3936   * 	The verifier will reject the program if *timer* is not from
  3937   * 	the same *map*.
  3938   *
  3939   * Returns
  3940   * 	0 on success.
  3941   * 	**-EBUSY** if *timer* is already initialized.
  3942   * 	**-EINVAL** if invalid *flags* are passed.
  3943   * 	**-EPERM** if *timer* is in a map that doesn't have any user references.
  3944   * 	The user space should either hold a file descriptor to a map with timers
  3945   * 	or pin such map in bpffs. When map is unpinned or file descriptor is
  3946   * 	closed all timers in the map will be cancelled and freed.
  3947   */
  3948  static long (*bpf_timer_init)(struct bpf_timer *timer, void *map, __u64 flags) = (void *) 169;
  3949  
  3950  /*
  3951   * bpf_timer_set_callback
  3952   *
  3953   * 	Configure the timer to call *callback_fn* static function.
  3954   *
  3955   * Returns
  3956   * 	0 on success.
  3957   * 	**-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier.
  3958   * 	**-EPERM** if *timer* is in a map that doesn't have any user references.
  3959   * 	The user space should either hold a file descriptor to a map with timers
  3960   * 	or pin such map in bpffs. When map is unpinned or file descriptor is
  3961   * 	closed all timers in the map will be cancelled and freed.
  3962   */
  3963  static long (*bpf_timer_set_callback)(struct bpf_timer *timer, void *callback_fn) = (void *) 170;
  3964  
  3965  /*
  3966   * bpf_timer_start
  3967   *
  3968   * 	Set timer expiration N nanoseconds from the current time. The
  3969   * 	configured callback will be invoked in soft irq context on some cpu
  3970   * 	and will not repeat unless another bpf_timer_start() is made.
  3971   * 	In such case the next invocation can migrate to a different cpu.
  3972   * 	Since struct bpf_timer is a field inside map element the map
  3973   * 	owns the timer. The bpf_timer_set_callback() will increment refcnt
  3974   * 	of BPF program to make sure that callback_fn code stays valid.
  3975   * 	When user space reference to a map reaches zero all timers
  3976   * 	in a map are cancelled and corresponding program's refcnts are
  3977   * 	decremented. This is done to make sure that Ctrl-C of a user
  3978   * 	process doesn't leave any timers running. If map is pinned in
  3979   * 	bpffs the callback_fn can re-arm itself indefinitely.
  3980   * 	bpf_map_update/delete_elem() helpers and user space sys_bpf commands
  3981   * 	cancel and free the timer in the given map element.
  3982   * 	The map can contain timers that invoke callback_fn-s from different
  3983   * 	programs. The same callback_fn can serve different timers from
  3984   * 	different maps if key/value layout matches across maps.
  3985   * 	Every bpf_timer_set_callback() can have different callback_fn.
  3986   *
  3987   *
  3988   * Returns
  3989   * 	0 on success.
  3990   * 	**-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier
  3991   * 	or invalid *flags* are passed.
  3992   */
  3993  static long (*bpf_timer_start)(struct bpf_timer *timer, __u64 nsecs, __u64 flags) = (void *) 171;
  3994  
  3995  /*
  3996   * bpf_timer_cancel
  3997   *
  3998   * 	Cancel the timer and wait for callback_fn to finish if it was running.
  3999   *
  4000   * Returns
  4001   * 	0 if the timer was not active.
  4002   * 	1 if the timer was active.
  4003   * 	**-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier.
  4004   * 	**-EDEADLK** if callback_fn tried to call bpf_timer_cancel() on its
  4005   * 	own timer which would have led to a deadlock otherwise.
  4006   */
  4007  static long (*bpf_timer_cancel)(struct bpf_timer *timer) = (void *) 172;
  4008  
  4009  /*
  4010   * bpf_get_func_ip
  4011   *
  4012   * 	Get address of the traced function (for tracing and kprobe programs).
  4013   *
  4014   * Returns
  4015   * 	Address of the traced function.
  4016   */
  4017  static __u64 (*bpf_get_func_ip)(void *ctx) = (void *) 173;
  4018  
  4019  /*
  4020   * bpf_get_attach_cookie
  4021   *
  4022   * 	Get bpf_cookie value provided (optionally) during the program
  4023   * 	attachment. It might be different for each individual
  4024   * 	attachment, even if BPF program itself is the same.
  4025   * 	Expects BPF program context *ctx* as a first argument.
  4026   *
  4027   * 	Supported for the following program types:
  4028   * 		- kprobe/uprobe;
  4029   * 		- tracepoint;
  4030   * 		- perf_event.
  4031   *
  4032   * Returns
  4033   * 	Value specified by user at BPF link creation/attachment time
  4034   * 	or 0, if it was not specified.
  4035   */
  4036  static __u64 (*bpf_get_attach_cookie)(void *ctx) = (void *) 174;
  4037  
  4038  /*
  4039   * bpf_task_pt_regs
  4040   *
  4041   * 	Get the struct pt_regs associated with **task**.
  4042   *
  4043   * Returns
  4044   * 	A pointer to struct pt_regs.
  4045   */
  4046  static long (*bpf_task_pt_regs)(struct task_struct *task) = (void *) 175;
  4047  
  4048  /*
  4049   * bpf_get_branch_snapshot
  4050   *
  4051   * 	Get branch trace from hardware engines like Intel LBR. The
  4052   * 	hardware engine is stopped shortly after the helper is
  4053   * 	called. Therefore, the user need to filter branch entries
  4054   * 	based on the actual use case. To capture branch trace
  4055   * 	before the trigger point of the BPF program, the helper
  4056   * 	should be called at the beginning of the BPF program.
  4057   *
  4058   * 	The data is stored as struct perf_branch_entry into output
  4059   * 	buffer *entries*. *size* is the size of *entries* in bytes.
  4060   * 	*flags* is reserved for now and must be zero.
  4061   *
  4062   *
  4063   * Returns
  4064   * 	On success, number of bytes written to *buf*. On error, a
  4065   * 	negative value.
  4066   *
  4067   * 	**-EINVAL** if *flags* is not zero.
  4068   *
  4069   * 	**-ENOENT** if architecture does not support branch records.
  4070   */
  4071  static long (*bpf_get_branch_snapshot)(void *entries, __u32 size, __u64 flags) = (void *) 176;
  4072  
  4073  /*
  4074   * bpf_trace_vprintk
  4075   *
  4076   * 	Behaves like **bpf_trace_printk**\ () helper, but takes an array of u64
  4077   * 	to format and can handle more format args as a result.
  4078   *
  4079   * 	Arguments are to be used as in **bpf_seq_printf**\ () helper.
  4080   *
  4081   * Returns
  4082   * 	The number of bytes written to the buffer, or a negative error
  4083   * 	in case of failure.
  4084   */
  4085  static long (*bpf_trace_vprintk)(const char *fmt, __u32 fmt_size, const void *data, __u32 data_len) = (void *) 177;
  4086  
  4087  /*
  4088   * bpf_skc_to_unix_sock
  4089   *
  4090   * 	Dynamically cast a *sk* pointer to a *unix_sock* pointer.
  4091   *
  4092   * Returns
  4093   * 	*sk* if casting is valid, or **NULL** otherwise.
  4094   */
  4095  static struct unix_sock *(*bpf_skc_to_unix_sock)(void *sk) = (void *) 178;
  4096  
  4097  /*
  4098   * bpf_kallsyms_lookup_name
  4099   *
  4100   * 	Get the address of a kernel symbol, returned in *res*. *res* is
  4101   * 	set to 0 if the symbol is not found.
  4102   *
  4103   * Returns
  4104   * 	On success, zero. On error, a negative value.
  4105   *
  4106   * 	**-EINVAL** if *flags* is not zero.
  4107   *
  4108   * 	**-EINVAL** if string *name* is not the same size as *name_sz*.
  4109   *
  4110   * 	**-ENOENT** if symbol is not found.
  4111   *
  4112   * 	**-EPERM** if caller does not have permission to obtain kernel address.
  4113   */
  4114  static long (*bpf_kallsyms_lookup_name)(const char *name, int name_sz, int flags, __u64 *res) = (void *) 179;
  4115  
  4116  /*
  4117   * bpf_find_vma
  4118   *
  4119   * 	Find vma of *task* that contains *addr*, call *callback_fn*
  4120   * 	function with *task*, *vma*, and *callback_ctx*.
  4121   * 	The *callback_fn* should be a static function and
  4122   * 	the *callback_ctx* should be a pointer to the stack.
  4123   * 	The *flags* is used to control certain aspects of the helper.
  4124   * 	Currently, the *flags* must be 0.
  4125   *
  4126   * 	The expected callback signature is
  4127   *
  4128   * 	long (\*callback_fn)(struct task_struct \*task, struct vm_area_struct \*vma, void \*callback_ctx);
  4129   *
  4130   *
  4131   * Returns
  4132   * 	0 on success.
  4133   * 	**-ENOENT** if *task->mm* is NULL, or no vma contains *addr*.
  4134   * 	**-EBUSY** if failed to try lock mmap_lock.
  4135   * 	**-EINVAL** for invalid **flags**.
  4136   */
  4137  static long (*bpf_find_vma)(struct task_struct *task, __u64 addr, void *callback_fn, void *callback_ctx, __u64 flags) = (void *) 180;
  4138  
  4139