1// SPDX-License-Identifier: GPL-2.0
2// Copyright (c) 2018 Facebook
3
4#include <stdlib.h>
5#include <string.h>
6#include <unistd.h>
7
8#include <arpa/inet.h>
9#include <net/if.h>
10#include <netinet/in.h>
11#include <sys/socket.h>
12#include <sys/types.h>
13
14
15#include <bpf/bpf.h>
16#include <bpf/libbpf.h>
17
18#include "cgroup_helpers.h"
19
20#define CGROUP_PATH		"/skb_cgroup_test"
21#define NUM_CGROUP_LEVELS	4
22
23/* RFC 4291, Section 2.7.1 */
24#define LINKLOCAL_MULTICAST	"ff02::1"
25
26static int mk_dst_addr(const char *ip, const char *iface,
27		       struct sockaddr_in6 *dst)
28{
29	memset(dst, 0, sizeof(*dst));
30
31	dst->sin6_family = AF_INET6;
32	dst->sin6_port = htons(1025);
33
34	if (inet_pton(AF_INET6, ip, &dst->sin6_addr) != 1) {
35		log_err("Invalid IPv6: %s", ip);
36		return -1;
37	}
38
39	dst->sin6_scope_id = if_nametoindex(iface);
40	if (!dst->sin6_scope_id) {
41		log_err("Failed to get index of iface: %s", iface);
42		return -1;
43	}
44
45	return 0;
46}
47
48static int send_packet(const char *iface)
49{
50	struct sockaddr_in6 dst;
51	char msg[] = "msg";
52	int err = 0;
53	int fd = -1;
54
55	if (mk_dst_addr(LINKLOCAL_MULTICAST, iface, &dst))
56		goto err;
57
58	fd = socket(AF_INET6, SOCK_DGRAM, 0);
59	if (fd == -1) {
60		log_err("Failed to create UDP socket");
61		goto err;
62	}
63
64	if (sendto(fd, &msg, sizeof(msg), 0, (const struct sockaddr *)&dst,
65		   sizeof(dst)) == -1) {
66		log_err("Failed to send datagram");
67		goto err;
68	}
69
70	goto out;
71err:
72	err = -1;
73out:
74	if (fd >= 0)
75		close(fd);
76	return err;
77}
78
79int get_map_fd_by_prog_id(int prog_id)
80{
81	struct bpf_prog_info info = {};
82	__u32 info_len = sizeof(info);
83	__u32 map_ids[1];
84	int prog_fd = -1;
85	int map_fd = -1;
86
87	prog_fd = bpf_prog_get_fd_by_id(prog_id);
88	if (prog_fd < 0) {
89		log_err("Failed to get fd by prog id %d", prog_id);
90		goto err;
91	}
92
93	info.nr_map_ids = 1;
94	info.map_ids = (__u64) (unsigned long) map_ids;
95
96	if (bpf_prog_get_info_by_fd(prog_fd, &info, &info_len)) {
97		log_err("Failed to get info by prog fd %d", prog_fd);
98		goto err;
99	}
100
101	if (!info.nr_map_ids) {
102		log_err("No maps found for prog fd %d", prog_fd);
103		goto err;
104	}
105
106	map_fd = bpf_map_get_fd_by_id(map_ids[0]);
107	if (map_fd < 0)
108		log_err("Failed to get fd by map id %d", map_ids[0]);
109err:
110	if (prog_fd >= 0)
111		close(prog_fd);
112	return map_fd;
113}
114
115int check_ancestor_cgroup_ids(int prog_id)
116{
117	__u64 actual_ids[NUM_CGROUP_LEVELS], expected_ids[NUM_CGROUP_LEVELS];
118	__u32 level;
119	int err = 0;
120	int map_fd;
121
122	expected_ids[0] = get_cgroup_id("/..");	/* root cgroup */
123	expected_ids[1] = get_cgroup_id("");
124	expected_ids[2] = get_cgroup_id(CGROUP_PATH);
125	expected_ids[3] = 0; /* non-existent cgroup */
126
127	map_fd = get_map_fd_by_prog_id(prog_id);
128	if (map_fd < 0)
129		goto err;
130
131	for (level = 0; level < NUM_CGROUP_LEVELS; ++level) {
132		if (bpf_map_lookup_elem(map_fd, &level, &actual_ids[level])) {
133			log_err("Failed to lookup key %d", level);
134			goto err;
135		}
136		if (actual_ids[level] != expected_ids[level]) {
137			log_err("%llx (actual) != %llx (expected), level: %u\n",
138				actual_ids[level], expected_ids[level], level);
139			goto err;
140		}
141	}
142
143	goto out;
144err:
145	err = -1;
146out:
147	if (map_fd >= 0)
148		close(map_fd);
149	return err;
150}
151
152int main(int argc, char **argv)
153{
154	int cgfd = -1;
155	int err = 0;
156
157	if (argc < 3) {
158		fprintf(stderr, "Usage: %s iface prog_id\n", argv[0]);
159		exit(EXIT_FAILURE);
160	}
161
162	/* Use libbpf 1.0 API mode */
163	libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
164
165	cgfd = cgroup_setup_and_join(CGROUP_PATH);
166	if (cgfd < 0)
167		goto err;
168
169	if (send_packet(argv[1]))
170		goto err;
171
172	if (check_ancestor_cgroup_ids(atoi(argv[2])))
173		goto err;
174
175	goto out;
176err:
177	err = -1;
178out:
179	close(cgfd);
180	cleanup_cgroup_environment();
181	printf("[%s]\n", err ? "FAIL" : "PASS");
182	return err;
183}
184