github.com/cilium/cilium@v1.16.2/bpf/tests/tc_nodeport_lb6_dsr_lb.c

// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright Authors of Cilium */

#include "common.h"

#include <bpf/ctx/skb.h>
#include "pktgen.h"

/* Set ETH_HLEN to 14 to indicate that the packet has a 14 byte ethernet header */
#define ETH_HLEN 14

/* Enable code paths under test */
#define ENABLE_IPV6
#define ENABLE_NODEPORT
#define ENABLE_DSR
#define DSR_ENCAP_GENEVE	3

#define DISABLE_LOOPBACK_LB

/* Skip ingress policy checks, not needed to validate hairpin flow */
#define USE_BPF_PROG_FOR_INGRESS_POLICY
#undef FORCE_LOCAL_POLICY_EVAL_AT_SOURCE

#define CLIENT_IP		{ .addr = { 0x1, 0x0, 0x0, 0x0, 0x0, 0x0 } }
#define CLIENT_PORT		__bpf_htons(111)

#define FRONTEND_IP		{ .addr = { 0x2, 0x0, 0x0, 0x0, 0x0, 0x0 } }
#define FRONTEND_PORT		tcp_svc_one

#define LB_IP			{ .addr = { 0x5, 0x0, 0x0, 0x0, 0x0, 0x0 } }
#define IPV6_DIRECT_ROUTING	LB_IP

#define BACKEND_IP		{ .addr = { 0x3, 0x0, 0x0, 0x0, 0x0, 0x0 } }
#define BACKEND_PORT		__bpf_htons(8080)

#define fib_lookup mock_fib_lookup

static volatile const __u8 *client_mac = mac_one;
/* this matches the default node_config.h: */
static volatile const __u8 lb_mac[ETH_ALEN] = { 0xce, 0x72, 0xa7, 0x03, 0x88, 0x56 };
static volatile const __u8 *remote_backend_mac = mac_five;

long mock_fib_lookup(__maybe_unused void *ctx, struct bpf_fib_lookup *params,
		     __maybe_unused int plen, __maybe_unused __u32 flags)
{
	params->ifindex = 0;

	if (1 /*memcmp(&params->ipv6_dst, BACKEND_IP)*/) {
		__bpf_memcpy_builtin(params->smac, (__u8 *)lb_mac, ETH_ALEN);
		__bpf_memcpy_builtin(params->dmac, (__u8 *)remote_backend_mac, ETH_ALEN);
	} else {
		__bpf_memcpy_builtin(params->smac, (__u8 *)lb_mac, ETH_ALEN);
		__bpf_memcpy_builtin(params->dmac, (__u8 *)client_mac, ETH_ALEN);
	}

	return BPF_FIB_LKUP_RET_SUCCESS;
}

#define SECCTX_FROM_IPCACHE 1

#include <bpf_host.c>

#include "lib/ipcache.h"
#include "lib/lb.h"

#define FROM_NETDEV	0
#define TO_NETDEV	1

struct {
	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
	__uint(key_size, sizeof(__u32));
	__uint(max_entries, 2);
	__array(values, int());
} entry_call_map __section(".maps") = {
	.values = {
		[FROM_NETDEV] = &cil_from_netdev,
		[TO_NETDEV] = &cil_to_netdev,
	},
};

/* Test that a SVC request that is LBed to a DSR remote backend
 * - gets DNATed,
 * - has IPv6 Extension inserted,
 * - gets redirected back out by TC
 */
PKTGEN("tc", "tc_nodeport_dsr_fwd")
int nodeport_dsr_fwd_pktgen(struct __ctx_buff *ctx)
{
	union v6addr frontend_ip = FRONTEND_IP;
	union v6addr client_ip = CLIENT_IP;
	struct pktgen builder;
	struct tcphdr *l4;
	void *data;

	/* Init packet builder */
	pktgen__init(&builder, ctx);

	l4 = pktgen__push_ipv6_tcp_packet(&builder,
					  (__u8 *)client_mac, (__u8 *)lb_mac,
					  (__u8 *)&client_ip, (__u8 *)&frontend_ip,
					  CLIENT_PORT, FRONTEND_PORT);
	if (!l4)
		return TEST_ERROR;

	data = pktgen__push_data(&builder, default_data, sizeof(default_data));
	if (!data)
		return TEST_ERROR;

	/* Calc lengths, set protocol fields and calc checksums */
	pktgen__finish(&builder);

	return 0;
}

SETUP("tc", "tc_nodeport_dsr_fwd")
int nodeport_dsr_fwd_setup(struct __ctx_buff *ctx)
{
	union v6addr frontend_ip = FRONTEND_IP;
	union v6addr backend_ip = BACKEND_IP;
	__u16 revnat_id = 1;

	lb_v6_add_service(&frontend_ip, FRONTEND_PORT, 1, revnat_id);
	lb_v6_add_backend(&frontend_ip, FRONTEND_PORT, 1, 124,
			  &backend_ip, BACKEND_PORT, IPPROTO_TCP, 0);

	ipcache_v6_add_entry(&backend_ip, 0, 112233, 0, 0);

	/* Jump into the entrypoint */
	tail_call_static(ctx, entry_call_map, FROM_NETDEV);
	/* Fail if we didn't jump */
	return TEST_ERROR;
}

CHECK("tc", "tc_nodeport_dsr_fwd")
int nodeport_dsr_fwd_check(__maybe_unused const struct __ctx_buff *ctx)
{
	union v6addr frontend_ip = FRONTEND_IP;
	union v6addr backend_ip = BACKEND_IP;
	union v6addr client_ip = CLIENT_IP;
	struct dsr_opt_v6 *opt;
	void *data, *data_end;
	__u32 *status_code;
	struct ipv6hdr *l3;
	struct tcphdr *l4;
	struct ethhdr *l2;

	test_init();

	data = (void *)(long)ctx_data(ctx);
	data_end = (void *)(long)ctx->data_end;

	if (data + sizeof(__u32) > data_end)
		test_fatal("status code out of bounds");

	status_code = data;

	assert(*status_code == CTX_ACT_REDIRECT);

	l2 = data + sizeof(__u32);
	if ((void *)l2 + sizeof(struct ethhdr) > data_end)
		test_fatal("l2 out of bounds");

	l3 = (void *)l2 + sizeof(struct ethhdr);
	if ((void *)l3 + sizeof(struct ipv6hdr) > data_end)
		test_fatal("l3 out of bounds");

	opt = (void *)l3 + sizeof(struct ipv6hdr);
	if ((void *)opt + sizeof(*opt) > data_end)
		test_fatal("l3 DSR extension out of bounds");

	l4 = (void *)opt + sizeof(*opt);
	if ((void *)l4 + sizeof(struct tcphdr) > data_end)
		test_fatal("l4 out of bounds");

	if (memcmp(l2->h_source, (__u8 *)lb_mac, ETH_ALEN) != 0)
		test_fatal("src MAC is not the LB MAC")
	if (memcmp(l2->h_dest, (__u8 *)remote_backend_mac, ETH_ALEN) != 0)
		test_fatal("dst MAC is not the backend MAC")

	if (l3->nexthdr != NEXTHDR_DEST)
		test_fatal("l3 header doesn't indicate DSR extension");

	if (!ipv6_addr_equals((union v6addr *)&l3->saddr, &client_ip))
		test_fatal("src IP has changed");
	if (!ipv6_addr_equals((union v6addr *)&l3->daddr, &backend_ip))
		test_fatal("dst IP hasn't been NATed to remote backend IP");

	if (opt->hdr.nexthdr != IPPROTO_TCP)
		test_fatal("nexthdr in DSR extension is bad")
	if (opt->hdr.hdrlen != DSR_IPV6_EXT_LEN)
		test_fatal("length in DSR extension is bad")
	if (opt->opt_type != DSR_IPV6_OPT_TYPE)
		test_fatal("opt_type in DSR extension is bad")
	if (opt->opt_len != DSR_IPV6_OPT_LEN)
		test_fatal("opt_len in DSR extension is bad")

	if (opt->port != FRONTEND_PORT)
		test_fatal("port in DSR extension is bad")
	if (!ipv6_addr_equals((union v6addr *)&opt->addr, &frontend_ip))
		test_fatal("addr in DSR extension is bad")

	if (l4->source != CLIENT_PORT)
		test_fatal("src port has changed");

	if (l4->dest != BACKEND_PORT)
		test_fatal("dst port hasn't been NATed to backend port");

	test_finish();
}