1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <linux/stddef.h>
4 #include <linux/bpf.h>
5 #include <sys/types.h>
6 #include <sys/socket.h>
7 #include <bpf/bpf_helpers.h>
8 #include <bpf/bpf_endian.h>
9
10 static __always_inline int bind_prog(struct bpf_sock_addr *ctx, int family)
11 {
12 struct bpf_sock *sk;
13
14 sk = ctx->sk;
15 if (!sk)
16 return 0;
17
18 if (sk->family != family)
19 return 0;
20
21 if (ctx->type != SOCK_STREAM)
22 return 0;
23
24 /* Return 1 OR'ed with the first bit set to indicate
25 * that CAP_NET_BIND_SERVICE should be bypassed.
26 */
27 if (ctx->user_port == bpf_htons(111))
28 return (1 | 2);
29
30 return 1;
31 }
32
33 SEC("cgroup/bind4")
34 int bind_v4_prog(struct bpf_sock_addr *ctx)
35 {
36 return bind_prog(ctx, AF_INET);
37 }
38
39 SEC("cgroup/bind6")
40 int bind_v6_prog(struct bpf_sock_addr *ctx)
41 {
42 return bind_prog(ctx, AF_INET6);
43 }
44
45 char _license[] SEC("license") = "GPL";
46
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