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 
12 struct socket_cookie {
13 	__u64 cookie_key;
14 	__u32 cookie_value;
15 };
16 
17 struct {
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  */
32 SEC("cgroup/connect6")
33 int 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 
51 SEC("sockops")
52 int 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 
78 SEC("fexit/inet_stream_connect")
79 int 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 
99 char _license[] SEC("license") = "GPL";
100