github.com/forest33/wtun@v0.3.1/conn/conn.go (about)

     1  /* SPDX-License-Identifier: MIT
     2   *
     3   * Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
     4   */
     5  
     6  // Package conn implements WireGuard's network connections.
     7  package conn
     8  
     9  import (
    10  	"errors"
    11  	"fmt"
    12  	"net/netip"
    13  	"reflect"
    14  	"runtime"
    15  	"strings"
    16  )
    17  
    18  const (
    19  	IdealBatchSize = 128 // maximum number of packets handled per read and write
    20  )
    21  
    22  // A ReceiveFunc receives at least one packet from the network and writes them
    23  // into packets. On a successful read it returns the number of elements of
    24  // sizes, packets, and endpoints that should be evaluated. Some elements of
    25  // sizes may be zero, and callers should ignore them. Callers must pass a sizes
    26  // and eps slice with a length greater than or equal to the length of packets.
    27  // These lengths must not exceed the length of the associated Bind.BatchSize().
    28  type ReceiveFunc func(packets [][]byte, sizes []int, eps []Endpoint) (n int, err error)
    29  
    30  // A Bind listens on a port for both IPv6 and IPv4 UDP traffic.
    31  //
    32  // A Bind interface may also be a PeekLookAtSocketFd or BindSocketToInterface,
    33  // depending on the platform-specific implementation.
    34  type Bind interface {
    35  	// Open puts the Bind into a listening state on a given port and reports the actual
    36  	// port that it bound to. Passing zero results in a random selection.
    37  	// fns is the set of functions that will be called to receive packets.
    38  	Open(port uint16) (fns []ReceiveFunc, actualPort uint16, err error)
    39  
    40  	// Close closes the Bind listener.
    41  	// All fns returned by Open must return net.ErrClosed after a call to Close.
    42  	Close() error
    43  
    44  	// SetMark sets the mark for each packet sent through this Bind.
    45  	// This mark is passed to the kernel as the socket option SO_MARK.
    46  	SetMark(mark uint32) error
    47  
    48  	// Send writes one or more packets in bufs to address ep. The length of
    49  	// bufs must not exceed BatchSize().
    50  	Send(bufs [][]byte, ep Endpoint) error
    51  
    52  	// ParseEndpoint creates a new endpoint from a string.
    53  	ParseEndpoint(s string) (Endpoint, error)
    54  
    55  	// BatchSize is the number of buffers expected to be passed to
    56  	// the ReceiveFuncs, and the maximum expected to be passed to SendBatch.
    57  	BatchSize() int
    58  }
    59  
    60  // BindSocketToInterface is implemented by Bind objects that support being
    61  // tied to a single network interface. Used by wireguard-windows.
    62  type BindSocketToInterface interface {
    63  	BindSocketToInterface4(interfaceIndex uint32, blackhole bool) error
    64  	BindSocketToInterface6(interfaceIndex uint32, blackhole bool) error
    65  }
    66  
    67  // PeekLookAtSocketFd is implemented by Bind objects that support having their
    68  // file descriptor peeked at. Used by wireguard-android.
    69  type PeekLookAtSocketFd interface {
    70  	PeekLookAtSocketFd4() (fd int, err error)
    71  	PeekLookAtSocketFd6() (fd int, err error)
    72  }
    73  
    74  // An Endpoint maintains the source/destination caching for a peer.
    75  //
    76  //	dst: the remote address of a peer ("endpoint" in uapi terminology)
    77  //	src: the local address from which datagrams originate going to the peer
    78  type Endpoint interface {
    79  	ClearSrc()           // clears the source address
    80  	SrcToString() string // returns the local source address (ip:port)
    81  	DstToString() string // returns the destination address (ip:port)
    82  	DstToBytes() []byte  // used for mac2 cookie calculations
    83  	DstIP() netip.Addr
    84  	SrcIP() netip.Addr
    85  }
    86  
    87  var (
    88  	ErrBindAlreadyOpen   = errors.New("bind is already open")
    89  	ErrWrongEndpointType = errors.New("endpoint type does not correspond with bind type")
    90  )
    91  
    92  func (fn ReceiveFunc) PrettyName() string {
    93  	name := runtime.FuncForPC(reflect.ValueOf(fn).Pointer()).Name()
    94  	// 0. cheese/taco.beansIPv6.func12.func21218-fm
    95  	name = strings.TrimSuffix(name, "-fm")
    96  	// 1. cheese/taco.beansIPv6.func12.func21218
    97  	if idx := strings.LastIndexByte(name, '/'); idx != -1 {
    98  		name = name[idx+1:]
    99  		// 2. taco.beansIPv6.func12.func21218
   100  	}
   101  	for {
   102  		var idx int
   103  		for idx = len(name) - 1; idx >= 0; idx-- {
   104  			if name[idx] < '0' || name[idx] > '9' {
   105  				break
   106  			}
   107  		}
   108  		if idx == len(name)-1 {
   109  			break
   110  		}
   111  		const dotFunc = ".func"
   112  		if !strings.HasSuffix(name[:idx+1], dotFunc) {
   113  			break
   114  		}
   115  		name = name[:idx+1-len(dotFunc)]
   116  		// 3. taco.beansIPv6.func12
   117  		// 4. taco.beansIPv6
   118  	}
   119  	if idx := strings.LastIndexByte(name, '.'); idx != -1 {
   120  		name = name[idx+1:]
   121  		// 5. beansIPv6
   122  	}
   123  	if name == "" {
   124  		return fmt.Sprintf("%p", fn)
   125  	}
   126  	if strings.HasSuffix(name, "IPv4") {
   127  		return "v4"
   128  	}
   129  	if strings.HasSuffix(name, "IPv6") {
   130  		return "v6"
   131  	}
   132  	return name
   133  }