1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2020 Isovalent, Inc.
3 #include "vmlinux.h"
4 #include <bpf/bpf_helpers.h>
5 
6 struct {
7 	__uint(type, BPF_MAP_TYPE_SOCKMAP);
8 	__uint(max_entries, 2);
9 	__type(key, __u32);
10 	__type(value, __u64);
11 } sock_map SEC(".maps");
12 
13 struct {
14 	__uint(type, BPF_MAP_TYPE_SOCKHASH);
15 	__uint(max_entries, 2);
16 	__type(key, __u32);
17 	__type(value, __u64);
18 } sock_hash SEC(".maps");
19 
20 struct {
21 	__uint(type, BPF_MAP_TYPE_SK_STORAGE);
22 	__uint(map_flags, BPF_F_NO_PREALLOC);
23 	__type(key, __u32);
24 	__type(value, __u64);
25 } socket_storage SEC(".maps");
26 
27 SEC("sk_msg")
prog_msg_verdict(struct sk_msg_md * msg)28 int prog_msg_verdict(struct sk_msg_md *msg)
29 {
30 	struct task_struct *task = (struct task_struct *)bpf_get_current_task();
31 	int verdict = SK_PASS;
32 	__u32 pid, tpid;
33 	__u64 *sk_stg;
34 
35 	pid = bpf_get_current_pid_tgid() >> 32;
36 	sk_stg = bpf_sk_storage_get(&socket_storage, msg->sk, 0, BPF_SK_STORAGE_GET_F_CREATE);
37 	if (!sk_stg)
38 		return SK_DROP;
39 	*sk_stg = pid;
40 	bpf_probe_read_kernel(&tpid , sizeof(tpid), &task->tgid);
41 	if (pid != tpid)
42 		verdict = SK_DROP;
43 	bpf_sk_storage_delete(&socket_storage, (void *)msg->sk);
44 	return verdict;
45 }
46 
47 char _license[] SEC("license") = "GPL";
48