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 "bpf_rlimit.h"
 19#include "cgroup_helpers.h"
 20
 21static int start_server(const struct sockaddr *addr, socklen_t len)
 22{
 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 (bind(fd, addr, len) == -1) {
 32		log_err("Failed to bind server socket");
 33		goto close_out;
 34	}
 35
 36	if (listen(fd, 128) == -1) {
 37		log_err("Failed to listen on server socket");
 38		goto close_out;
 39	}
 40
 41	goto out;
 42
 43close_out:
 44	close(fd);
 45	fd = -1;
 46out:
 47	return fd;
 48}
 49
 50static int connect_to_server(int server_fd)
 51{
 52	struct sockaddr_storage addr;
 53	socklen_t len = sizeof(addr);
 54	int fd = -1;
 55
 56	if (getsockname(server_fd, (struct sockaddr *)&addr, &len)) {
 57		log_err("Failed to get server addr");
 58		goto out;
 59	}
 60
 61	fd = socket(addr.ss_family, SOCK_STREAM, 0);
 62	if (fd == -1) {
 63		log_err("Failed to create client socket");
 64		goto out;
 65	}
 66
 67	if (connect(fd, (const struct sockaddr *)&addr, len) == -1) {
 68		log_err("Fail to connect to server");
 69		goto close_out;
 70	}
 71
 72	goto out;
 73
 74close_out:
 75	close(fd);
 76	fd = -1;
 77out:
 78	return fd;
 79}
 80
 81static int get_map_fd_by_prog_id(int prog_id, bool *xdp)
 82{
 83	struct bpf_prog_info info = {};
 84	__u32 info_len = sizeof(info);
 85	__u32 map_ids[1];
 86	int prog_fd = -1;
 87	int map_fd = -1;
 88
 89	prog_fd = bpf_prog_get_fd_by_id(prog_id);
 90	if (prog_fd < 0) {
 91		log_err("Failed to get fd by prog id %d", prog_id);
 92		goto err;
 93	}
 94
 95	info.nr_map_ids = 1;
 96	info.map_ids = (__u64)(unsigned long)map_ids;
 97
 98	if (bpf_obj_get_info_by_fd(prog_fd, &info, &info_len)) {
 99		log_err("Failed to get info by prog fd %d", prog_fd);
100		goto err;
101	}
102
103	if (!info.nr_map_ids) {
104		log_err("No maps found for prog fd %d", prog_fd);
105		goto err;
106	}
107
108	*xdp = info.type == BPF_PROG_TYPE_XDP;
109
110	map_fd = bpf_map_get_fd_by_id(map_ids[0]);
111	if (map_fd < 0)
112		log_err("Failed to get fd by map id %d", map_ids[0]);
113err:
114	if (prog_fd >= 0)
115		close(prog_fd);
116	return map_fd;
117}
118
119static int run_test(int server_fd, int results_fd, bool xdp)
120{
121	int client = -1, srv_client = -1;
122	int ret = 0;
123	__u32 key = 0;
124	__u32 key_gen = 1;
125	__u32 key_mss = 2;
126	__u32 value = 0;
127	__u32 value_gen = 0;
128	__u32 value_mss = 0;
129
130	if (bpf_map_update_elem(results_fd, &key, &value, 0) < 0) {
131		log_err("Can't clear results");
132		goto err;
133	}
134
135	if (bpf_map_update_elem(results_fd, &key_gen, &value_gen, 0) < 0) {
136		log_err("Can't clear results");
137		goto err;
138	}
139
140	if (bpf_map_update_elem(results_fd, &key_mss, &value_mss, 0) < 0) {
141		log_err("Can't clear results");
142		goto err;
143	}
144
145	client = connect_to_server(server_fd);
146	if (client == -1)
147		goto err;
148
149	srv_client = accept(server_fd, NULL, 0);
150	if (srv_client == -1) {
151		log_err("Can't accept connection");
152		goto err;
153	}
154
155	if (bpf_map_lookup_elem(results_fd, &key, &value) < 0) {
156		log_err("Can't lookup result");
157		goto err;
158	}
159
160	if (value == 0) {
161		log_err("Didn't match syncookie: %u", value);
162		goto err;
163	}
164
165	if (bpf_map_lookup_elem(results_fd, &key_gen, &value_gen) < 0) {
166		log_err("Can't lookup result");
167		goto err;
168	}
169
170	if (xdp && value_gen == 0) {
171		// SYN packets do not get passed through generic XDP, skip the
172		// rest of the test.
173		printf("Skipping XDP cookie check\n");
174		goto out;
175	}
176
177	if (bpf_map_lookup_elem(results_fd, &key_mss, &value_mss) < 0) {
178		log_err("Can't lookup result");
179		goto err;
180	}
181
182	if (value != value_gen) {
183		log_err("BPF generated cookie does not match kernel one");
184		goto err;
185	}
186
187	if (value_mss < 536 || value_mss > USHRT_MAX) {
188		log_err("Unexpected MSS retrieved");
189		goto err;
190	}
191
192	goto out;
193
194err:
195	ret = 1;
196out:
197	close(client);
198	close(srv_client);
199	return ret;
200}
201
202int main(int argc, char **argv)
203{
204	struct sockaddr_in addr4;
205	struct sockaddr_in6 addr6;
206	int server = -1;
207	int server_v6 = -1;
208	int results = -1;
209	int err = 0;
210	bool xdp;
211
212	if (argc < 2) {
213		fprintf(stderr, "Usage: %s prog_id\n", argv[0]);
214		exit(1);
215	}
216
217	results = get_map_fd_by_prog_id(atoi(argv[1]), &xdp);
218	if (results < 0) {
219		log_err("Can't get map");
220		goto err;
221	}
222
223	memset(&addr4, 0, sizeof(addr4));
224	addr4.sin_family = AF_INET;
225	addr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
226	addr4.sin_port = 0;
227
228	memset(&addr6, 0, sizeof(addr6));
229	addr6.sin6_family = AF_INET6;
230	addr6.sin6_addr = in6addr_loopback;
231	addr6.sin6_port = 0;
232
233	server = start_server((const struct sockaddr *)&addr4, sizeof(addr4));
234	if (server == -1)
235		goto err;
236
237	server_v6 = start_server((const struct sockaddr *)&addr6,
238				 sizeof(addr6));
239	if (server_v6 == -1)
240		goto err;
241
242	if (run_test(server, results, xdp))
243		goto err;
244
245	if (run_test(server_v6, results, xdp))
246		goto err;
247
248	printf("ok\n");
249	goto out;
250err:
251	err = 1;
252out:
253	close(server);
254	close(server_v6);
255	close(results);
256	return err;
257}