1// SPDX-License-Identifier: GPL-2.0
2// Copyright (c) 2018 Facebook
3
4#include "vmlinux.h"
5
6#include <bpf/bpf_helpers.h>
7#include <bpf/bpf_endian.h>
8#include <bpf/bpf_tracing.h>
9
10#define AF_INET6 10
11
12struct socket_cookie {
13	__u64 cookie_key;
14	__u32 cookie_value;
15};
16
17struct {
18	__uint(type, BPF_MAP_TYPE_SK_STORAGE);
19	__uint(map_flags, BPF_F_NO_PREALLOC);
20	__type(key, int);
21	__type(value, struct socket_cookie);
22} socket_cookies SEC(".maps");
23
24/*
25 * These three programs get executed in a row on connect() syscalls. The
26 * userspace side of the test creates a client socket, issues a connect() on it
27 * and then checks that the local storage associated with this socket has:
28 * cookie_value == local_port << 8 | 0xFF
29 * The different parts of this cookie_value are appended by those hooks if they
30 * all agree on the output of bpf_get_socket_cookie().
31 */
32SEC("cgroup/connect6")
33int set_cookie(struct bpf_sock_addr *ctx)
34{
35	struct socket_cookie *p;
36
37	if (ctx->family != AF_INET6 || ctx->user_family != AF_INET6)
38		return 1;
39
40	p = bpf_sk_storage_get(&socket_cookies, ctx->sk, 0,
41			       BPF_SK_STORAGE_GET_F_CREATE);
42	if (!p)
43		return 1;
44
45	p->cookie_value = 0xF;
46	p->cookie_key = bpf_get_socket_cookie(ctx);
47
48	return 1;
49}
50
51SEC("sockops")
52int update_cookie_sockops(struct bpf_sock_ops *ctx)
53{
54	struct bpf_sock *sk = ctx->sk;
55	struct socket_cookie *p;
56
57	if (ctx->family != AF_INET6)
58		return 1;
59
60	if (ctx->op != BPF_SOCK_OPS_TCP_CONNECT_CB)
61		return 1;
62
63	if (!sk)
64		return 1;
65
66	p = bpf_sk_storage_get(&socket_cookies, sk, 0, 0);
67	if (!p)
68		return 1;
69
70	if (p->cookie_key != bpf_get_socket_cookie(ctx))
71		return 1;
72
73	p->cookie_value |= (ctx->local_port << 8);
74
75	return 1;
76}
77
78SEC("fexit/inet_stream_connect")
79int BPF_PROG(update_cookie_tracing, struct socket *sock,
80	     struct sockaddr *uaddr, int addr_len, int flags)
81{
82	struct socket_cookie *p;
83
84	if (uaddr->sa_family != AF_INET6)
85		return 0;
86
87	p = bpf_sk_storage_get(&socket_cookies, sock->sk, 0, 0);
88	if (!p)
89		return 0;
90
91	if (p->cookie_key != bpf_get_socket_cookie(sock->sk))
92		return 0;
93
94	p->cookie_value |= 0xF0;
95
96	return 0;
97}
98
99char _license[] SEC("license") = "GPL";
100