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 
start_server(const struct sockaddr * addr,socklen_t len,bool dual)20 static 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 
51 close_out:
52 	close(fd);
53 	fd = -1;
54 out:
55 	return fd;
56 }
57 
connect_to_server(const struct sockaddr * addr,socklen_t len)58 static 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 
75 close_out:
76 	close(fd);
77 	fd = -1;
78 out:
79 	return fd;
80 }
81 
get_map_fd_by_prog_id(int prog_id,bool * xdp)82 static 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]);
114 err:
115 	if (prog_fd >= 0)
116 		close(prog_fd);
117 	return map_fd;
118 }
119 
run_test(int server_fd,int results_fd,bool xdp,const struct sockaddr * addr,socklen_t len)120 static 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 
196 err:
197 	ret = 1;
198 out:
199 	close(client);
200 	close(srv_client);
201 	return ret;
202 }
203 
get_port(int server_fd,in_port_t * port)204 static 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 
main(int argc,char ** argv)219 int 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;
291 err:
292 	err = 1;
293 out:
294 	close(server);
295 	close(server_v6);
296 	close(server_dual);
297 	close(results);
298 	return err;
299 }
300