mptcp_sockmap.c

 1// SPDX-License-Identifier: GPL-2.0
 2
 3#include "bpf_tracing_net.h"
 4
 5char _license[] SEC("license") = "GPL";
 6
 7int sk_index;
 8int redirect_idx;
 9int trace_port;
10int helper_ret;
11struct {
12	__uint(type, BPF_MAP_TYPE_SOCKMAP);
13	__uint(key_size, sizeof(__u32));
14	__uint(value_size, sizeof(__u32));
15	__uint(max_entries, 100);
16} sock_map SEC(".maps");
17
18SEC("sockops")
19int mptcp_sockmap_inject(struct bpf_sock_ops *skops)
20{
21	struct bpf_sock *sk;
22
23	/* only accept specified connection */
24	if (skops->local_port != trace_port ||
25	    skops->op != BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB)
26		return 1;
27
28	sk = skops->sk;
29	if (!sk)
30		return 1;
31
32	/* update sk handler */
33	helper_ret = bpf_sock_map_update(skops, &sock_map, &sk_index, BPF_NOEXIST);
34
35	return 1;
36}
37
38SEC("sk_skb/stream_verdict")
39int mptcp_sockmap_redirect(struct __sk_buff *skb)
40{
41	/* redirect skb to the sk under sock_map[redirect_idx] */
42	return bpf_sk_redirect_map(skb, &sock_map, redirect_idx, 0);
43}