1// SPDX-License-Identifier: GPL-2.0
 2// Copyright (c) 2018 Facebook
 3
 4#include <string.h>
 5
 6#include <linux/stddef.h>
 7#include <linux/bpf.h>
 8#include <linux/in.h>
 9#include <linux/in6.h>
10#include <sys/socket.h>
11
12#include "bpf_helpers.h"
13#include "bpf_endian.h"
14
15#define SRC_REWRITE_IP4		0x7f000004U
16#define DST_REWRITE_IP4		0x7f000001U
17#define DST_REWRITE_PORT4	4444
18
19int _version SEC("version") = 1;
20
21SEC("cgroup/connect4")
22int connect_v4_prog(struct bpf_sock_addr *ctx)
23{
24	struct sockaddr_in sa;
25
26	/* Rewrite destination. */
27	ctx->user_ip4 = bpf_htonl(DST_REWRITE_IP4);
28	ctx->user_port = bpf_htons(DST_REWRITE_PORT4);
29
30	if (ctx->type == SOCK_DGRAM || ctx->type == SOCK_STREAM) {
31		///* Rewrite source. */
32		memset(&sa, 0, sizeof(sa));
33
34		sa.sin_family = AF_INET;
35		sa.sin_port = bpf_htons(0);
36		sa.sin_addr.s_addr = bpf_htonl(SRC_REWRITE_IP4);
37
38		if (bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)) != 0)
39			return 0;
40	}
41
42	return 1;
43}
44
45char _license[] SEC("license") = "GPL";