1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2018 Facebook
3
4 #include <linux/bpf.h>
5 #include <sys/socket.h>
6
7 #include "bpf_helpers.h"
8 #include "bpf_endian.h"
9
10 struct bpf_map_def SEC("maps") socket_cookies = {
11 .type = BPF_MAP_TYPE_HASH,
12 .key_size = sizeof(__u64),
13 .value_size = sizeof(__u32),
14 .max_entries = 1 << 8,
15 };
16
17 SEC("cgroup/connect6")
set_cookie(struct bpf_sock_addr * ctx)18 int set_cookie(struct bpf_sock_addr *ctx)
19 {
20 __u32 cookie_value = 0xFF;
21 __u64 cookie_key;
22
23 if (ctx->family != AF_INET6 || ctx->user_family != AF_INET6)
24 return 1;
25
26 cookie_key = bpf_get_socket_cookie(ctx);
27 if (bpf_map_update_elem(&socket_cookies, &cookie_key, &cookie_value, 0))
28 return 0;
29
30 return 1;
31 }
32
33 SEC("sockops")
update_cookie(struct bpf_sock_ops * ctx)34 int update_cookie(struct bpf_sock_ops *ctx)
35 {
36 __u32 new_cookie_value;
37 __u32 *cookie_value;
38 __u64 cookie_key;
39
40 if (ctx->family != AF_INET6)
41 return 1;
42
43 if (ctx->op != BPF_SOCK_OPS_TCP_CONNECT_CB)
44 return 1;
45
46 cookie_key = bpf_get_socket_cookie(ctx);
47
48 cookie_value = bpf_map_lookup_elem(&socket_cookies, &cookie_key);
49 if (!cookie_value)
50 return 1;
51
52 new_cookie_value = (ctx->local_port << 8) | *cookie_value;
53 bpf_map_update_elem(&socket_cookies, &cookie_key, &new_cookie_value, 0);
54
55 return 1;
56 }
57
58 int _version SEC("version") = 1;
59
60 char _license[] SEC("license") = "GPL";
61