1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/stddef.h>
4#include <linux/bpf.h>
5#include <linux/in.h>
6#include <sys/socket.h>
7
8#include <bpf/bpf_helpers.h>
9#include <bpf/bpf_endian.h>
10
11#include <bpf_sockopt_helpers.h>
12
13#define SERV4_IP		0xc0a801feU /* 192.168.1.254 */
14#define SERV4_PORT		4040
15
16SEC("cgroup/recvmsg4")
17int recvmsg4_prog(struct bpf_sock_addr *ctx)
18{
19	struct bpf_sock *sk;
20
21	sk = ctx->sk;
22	if (!sk)
23		return 1;
24
25	if (sk->family != AF_INET)
26		return 1;
27
28	if (ctx->type != SOCK_STREAM && ctx->type != SOCK_DGRAM)
29		return 1;
30
31	if (!get_set_sk_priority(ctx))
32		return 1;
33
34	ctx->user_ip4 = bpf_htonl(SERV4_IP);
35	ctx->user_port = bpf_htons(SERV4_PORT);
36
37	return 1;
38}
39
40char _license[] SEC("license") = "GPL";
41