1// SPDX-License-Identifier: GPL-2.0
2// Copyright (c) 2018 Facebook
3// Copyright (c) 2019 Cloudflare
4
5#include <limits.h>
6#include <string.h>
7#include <stdlib.h>
8#include <unistd.h>
9
10#include <arpa/inet.h>
11#include <netinet/in.h>
12#include <sys/types.h>
13#include <sys/socket.h>
14
15#include <bpf/bpf.h>
16#include <bpf/libbpf.h>
17
18#include "cgroup_helpers.h"
19
20static int start_server(const struct sockaddr *addr, socklen_t len, bool dual)
21{
22	int mode = !dual;
23	int fd;
24
25	fd = socket(addr->sa_family, SOCK_STREAM, 0);
26	if (fd == -1) {
27		log_err("Failed to create server socket");
28		goto out;
29	}
30
31	if (addr->sa_family == AF_INET6) {
32		if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, (char *)&mode,
33			       sizeof(mode)) == -1) {
34			log_err("Failed to set the dual-stack mode");
35			goto close_out;
36		}
37	}
38
39	if (bind(fd, addr, len) == -1) {
40		log_err("Failed to bind server socket");
41		goto close_out;
42	}
43
44	if (listen(fd, 128) == -1) {
45		log_err("Failed to listen on server socket");
46		goto close_out;
47	}
48
49	goto out;
50
51close_out:
52	close(fd);
53	fd = -1;
54out:
55	return fd;
56}
57
58static int connect_to_server(const struct sockaddr *addr, socklen_t len)
59{
60	int fd = -1;
61
62	fd = socket(addr->sa_family, SOCK_STREAM, 0);
63	if (fd == -1) {
64		log_err("Failed to create client socket");
65		goto out;
66	}
67
68	if (connect(fd, (const struct sockaddr *)addr, len) == -1) {
69		log_err("Fail to connect to server");
70		goto close_out;
71	}
72
73	goto out;
74
75close_out:
76	close(fd);
77	fd = -1;
78out:
79	return fd;
80}
81
82static int get_map_fd_by_prog_id(int prog_id, bool *xdp)
83{
84	struct bpf_prog_info info = {};
85	__u32 info_len = sizeof(info);
86	__u32 map_ids[1];
87	int prog_fd = -1;
88	int map_fd = -1;
89
90	prog_fd = bpf_prog_get_fd_by_id(prog_id);
91	if (prog_fd < 0) {
92		log_err("Failed to get fd by prog id %d", prog_id);
93		goto err;
94	}
95
96	info.nr_map_ids = 1;
97	info.map_ids = (__u64)(unsigned long)map_ids;
98
99	if (bpf_prog_get_info_by_fd(prog_fd, &info, &info_len)) {
100		log_err("Failed to get info by prog fd %d", prog_fd);
101		goto err;
102	}
103
104	if (!info.nr_map_ids) {
105		log_err("No maps found for prog fd %d", prog_fd);
106		goto err;
107	}
108
109	*xdp = info.type == BPF_PROG_TYPE_XDP;
110
111	map_fd = bpf_map_get_fd_by_id(map_ids[0]);
112	if (map_fd < 0)
113		log_err("Failed to get fd by map id %d", map_ids[0]);
114err:
115	if (prog_fd >= 0)
116		close(prog_fd);
117	return map_fd;
118}
119
120static int run_test(int server_fd, int results_fd, bool xdp,
121		    const struct sockaddr *addr, socklen_t len)
122{
123	int client = -1, srv_client = -1;
124	int ret = 0;
125	__u32 key = 0;
126	__u32 key_gen = 1;
127	__u32 key_mss = 2;
128	__u32 value = 0;
129	__u32 value_gen = 0;
130	__u32 value_mss = 0;
131
132	if (bpf_map_update_elem(results_fd, &key, &value, 0) < 0) {
133		log_err("Can't clear results");
134		goto err;
135	}
136
137	if (bpf_map_update_elem(results_fd, &key_gen, &value_gen, 0) < 0) {
138		log_err("Can't clear results");
139		goto err;
140	}
141
142	if (bpf_map_update_elem(results_fd, &key_mss, &value_mss, 0) < 0) {
143		log_err("Can't clear results");
144		goto err;
145	}
146
147	client = connect_to_server(addr, len);
148	if (client == -1)
149		goto err;
150
151	srv_client = accept(server_fd, NULL, 0);
152	if (srv_client == -1) {
153		log_err("Can't accept connection");
154		goto err;
155	}
156
157	if (bpf_map_lookup_elem(results_fd, &key, &value) < 0) {
158		log_err("Can't lookup result");
159		goto err;
160	}
161
162	if (value == 0) {
163		log_err("Didn't match syncookie: %u", value);
164		goto err;
165	}
166
167	if (bpf_map_lookup_elem(results_fd, &key_gen, &value_gen) < 0) {
168		log_err("Can't lookup result");
169		goto err;
170	}
171
172	if (xdp && value_gen == 0) {
173		// SYN packets do not get passed through generic XDP, skip the
174		// rest of the test.
175		printf("Skipping XDP cookie check\n");
176		goto out;
177	}
178
179	if (bpf_map_lookup_elem(results_fd, &key_mss, &value_mss) < 0) {
180		log_err("Can't lookup result");
181		goto err;
182	}
183
184	if (value != value_gen) {
185		log_err("BPF generated cookie does not match kernel one");
186		goto err;
187	}
188
189	if (value_mss < 536 || value_mss > USHRT_MAX) {
190		log_err("Unexpected MSS retrieved");
191		goto err;
192	}
193
194	goto out;
195
196err:
197	ret = 1;
198out:
199	close(client);
200	close(srv_client);
201	return ret;
202}
203
204static bool get_port(int server_fd, in_port_t *port)
205{
206	struct sockaddr_in addr;
207	socklen_t len = sizeof(addr);
208
209	if (getsockname(server_fd, (struct sockaddr *)&addr, &len)) {
210		log_err("Failed to get server addr");
211		return false;
212	}
213
214	/* sin_port and sin6_port are located at the same offset. */
215	*port = addr.sin_port;
216	return true;
217}
218
219int main(int argc, char **argv)
220{
221	struct sockaddr_in addr4;
222	struct sockaddr_in6 addr6;
223	struct sockaddr_in addr4dual;
224	struct sockaddr_in6 addr6dual;
225	int server = -1;
226	int server_v6 = -1;
227	int server_dual = -1;
228	int results = -1;
229	int err = 0;
230	bool xdp;
231
232	if (argc < 2) {
233		fprintf(stderr, "Usage: %s prog_id\n", argv[0]);
234		exit(1);
235	}
236
237	/* Use libbpf 1.0 API mode */
238	libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
239
240	results = get_map_fd_by_prog_id(atoi(argv[1]), &xdp);
241	if (results < 0) {
242		log_err("Can't get map");
243		goto err;
244	}
245
246	memset(&addr4, 0, sizeof(addr4));
247	addr4.sin_family = AF_INET;
248	addr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
249	addr4.sin_port = 0;
250	memcpy(&addr4dual, &addr4, sizeof(addr4dual));
251
252	memset(&addr6, 0, sizeof(addr6));
253	addr6.sin6_family = AF_INET6;
254	addr6.sin6_addr = in6addr_loopback;
255	addr6.sin6_port = 0;
256
257	memset(&addr6dual, 0, sizeof(addr6dual));
258	addr6dual.sin6_family = AF_INET6;
259	addr6dual.sin6_addr = in6addr_any;
260	addr6dual.sin6_port = 0;
261
262	server = start_server((const struct sockaddr *)&addr4, sizeof(addr4),
263			      false);
264	if (server == -1 || !get_port(server, &addr4.sin_port))
265		goto err;
266
267	server_v6 = start_server((const struct sockaddr *)&addr6,
268				 sizeof(addr6), false);
269	if (server_v6 == -1 || !get_port(server_v6, &addr6.sin6_port))
270		goto err;
271
272	server_dual = start_server((const struct sockaddr *)&addr6dual,
273				   sizeof(addr6dual), true);
274	if (server_dual == -1 || !get_port(server_dual, &addr4dual.sin_port))
275		goto err;
276
277	if (run_test(server, results, xdp,
278		     (const struct sockaddr *)&addr4, sizeof(addr4)))
279		goto err;
280
281	if (run_test(server_v6, results, xdp,
282		     (const struct sockaddr *)&addr6, sizeof(addr6)))
283		goto err;
284
285	if (run_test(server_dual, results, xdp,
286		     (const struct sockaddr *)&addr4dual, sizeof(addr4dual)))
287		goto err;
288
289	printf("ok\n");
290	goto out;
291err:
292	err = 1;
293out:
294	close(server);
295	close(server_v6);
296	close(server_dual);
297	close(results);
298	return err;
299}
300