1// SPDX-License-Identifier: GPL-2.0
2#include "vmlinux.h"
3#include <bpf/bpf_helpers.h>
4#include <bpf/bpf_tracing.h>
5#include <bpf/bpf_core_read.h>
6#include "bpf_misc.h"
7
8static struct sockaddr_in old;
9
10static int handle_sys_connect_common(struct sockaddr_in *uservaddr)
11{
12	struct sockaddr_in new;
13
14	bpf_probe_read_user(&old, sizeof(old), uservaddr);
15	__builtin_memset(&new, 0xab, sizeof(new));
16	bpf_probe_write_user(uservaddr, &new, sizeof(new));
17
18	return 0;
19}
20
21SEC("ksyscall/connect")
22int BPF_KSYSCALL(handle_sys_connect, int fd, struct sockaddr_in *uservaddr,
23		 int addrlen)
24{
25	return handle_sys_connect_common(uservaddr);
26}
27
28#if defined(bpf_target_s390)
29#ifndef SYS_CONNECT
30#define SYS_CONNECT 3
31#endif
32
33SEC("ksyscall/socketcall")
34int BPF_KSYSCALL(handle_sys_socketcall, int call, unsigned long *args)
35{
36	if (call == SYS_CONNECT) {
37		struct sockaddr_in *uservaddr;
38
39		bpf_probe_read_user(&uservaddr, sizeof(uservaddr), &args[1]);
40		return handle_sys_connect_common(uservaddr);
41	}
42
43	return 0;
44}
45#endif
46
47char _license[] SEC("license") = "GPL";
48