1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2023, SUSE. */
3 
4 #include "vmlinux.h"
5 #include <bpf/bpf_tracing.h>
6 #include "bpf_tracing_net.h"
7 
8 char _license[] SEC("license") = "GPL";
9 
10 SEC("fmod_ret/update_socket_protocol")
11 int BPF_PROG(mptcpify, int family, int type, int protocol)
12 {
13 	if ((family == AF_INET || family == AF_INET6) &&
14 	    type == SOCK_STREAM &&
15 	    (!protocol || protocol == IPPROTO_TCP)) {
16 		return IPPROTO_MPTCP;
17 	}
18 
19 	return protocol;
20 }
21