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
10static __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
33SEC("cgroup/bind4")
34int bind_v4_prog(struct bpf_sock_addr *ctx)
35{
36	return bind_prog(ctx, AF_INET);
37}
38
39SEC("cgroup/bind6")
40int bind_v6_prog(struct bpf_sock_addr *ctx)
41{
42	return bind_prog(ctx, AF_INET6);
43}
44
45char _license[] SEC("license") = "GPL";
46