bpf/progs/test_skc_to_unix_sock.c

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 /* Copyright (c) 2021 Hengqi Chen */
0003
0004 #include "vmlinux.h"
0005 #include <bpf/bpf_helpers.h>
0006 #include <bpf/bpf_tracing.h>
0007 #include "bpf_tracing_net.h"
0008
0009 const volatile pid_t my_pid = 0;
0010 char path[256] = {};
0011
0012 SEC("fentry/unix_listen")
0013 int BPF_PROG(unix_listen, struct socket *sock, int backlog)
0014 {
0015     pid_t pid = bpf_get_current_pid_tgid() >> 32;
0016     struct unix_sock *unix_sk;
0017     int i, len;
0018
0019     if (pid != my_pid)
0020         return 0;
0021
0022     unix_sk = (struct unix_sock *)bpf_skc_to_unix_sock(sock->sk);
0023     if (!unix_sk)
0024         return 0;
0025
0026     if (unix_sk->addr->name->sun_path[0])
0027         return 0;
0028
0029     len = unix_sk->addr->len - sizeof(short);
0030     path[0] = '@';
0031     for (i = 1; i < len; i++) {
0032         if (i >= sizeof(struct sockaddr_un))
0033             break;
0034
0035         path[i] = unix_sk->addr->name->sun_path[i];
0036     }
0037     return 0;
0038 }
0039
0040 char _license[] SEC("license") = "GPL";