1// SPDX-License-Identifier: GPL-2.0
2// Copyright (c) 2020 Isovalent, Inc.
3#include "vmlinux.h"
4#include <bpf/bpf_helpers.h>
5
6struct {
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
13struct {
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
20struct {
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
27SEC("sk_msg")
28int 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
47char _license[] SEC("license") = "GPL";
48