selftests/bpf/test_tcp_check_syncookie_user.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 // Copyright (c) 2018 Facebook
0003 // Copyright (c) 2019 Cloudflare
0004
0005 #include <limits.h>
0006 #include <string.h>
0007 #include <stdlib.h>
0008 #include <unistd.h>
0009
0010 #include <arpa/inet.h>
0011 #include <netinet/in.h>
0012 #include <sys/types.h>
0013 #include <sys/socket.h>
0014
0015 #include <bpf/bpf.h>
0016 #include <bpf/libbpf.h>
0017
0018 #include "cgroup_helpers.h"
0019
0020 static int start_server(const struct sockaddr *addr, socklen_t len, bool dual)
0021 {
0022     int mode = !dual;
0023     int fd;
0024
0025     fd = socket(addr->sa_family, SOCK_STREAM, 0);
0026     if (fd == -1) {
0027         log_err("Failed to create server socket");
0028         goto out;
0029     }
0030
0031     if (addr->sa_family == AF_INET6) {
0032         if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, (char *)&mode,
0033                    sizeof(mode)) == -1) {
0034             log_err("Failed to set the dual-stack mode");
0035             goto close_out;
0036         }
0037     }
0038
0039     if (bind(fd, addr, len) == -1) {
0040         log_err("Failed to bind server socket");
0041         goto close_out;
0042     }
0043
0044     if (listen(fd, 128) == -1) {
0045         log_err("Failed to listen on server socket");
0046         goto close_out;
0047     }
0048
0049     goto out;
0050
0051 close_out:
0052     close(fd);
0053     fd = -1;
0054 out:
0055     return fd;
0056 }
0057
0058 static int connect_to_server(const struct sockaddr *addr, socklen_t len)
0059 {
0060     int fd = -1;
0061
0062     fd = socket(addr->sa_family, SOCK_STREAM, 0);
0063     if (fd == -1) {
0064         log_err("Failed to create client socket");
0065         goto out;
0066     }
0067
0068     if (connect(fd, (const struct sockaddr *)addr, len) == -1) {
0069         log_err("Fail to connect to server");
0070         goto close_out;
0071     }
0072
0073     goto out;
0074
0075 close_out:
0076     close(fd);
0077     fd = -1;
0078 out:
0079     return fd;
0080 }
0081
0082 static int get_map_fd_by_prog_id(int prog_id, bool *xdp)
0083 {
0084     struct bpf_prog_info info = {};
0085     __u32 info_len = sizeof(info);
0086     __u32 map_ids[1];
0087     int prog_fd = -1;
0088     int map_fd = -1;
0089
0090     prog_fd = bpf_prog_get_fd_by_id(prog_id);
0091     if (prog_fd < 0) {
0092         log_err("Failed to get fd by prog id %d", prog_id);
0093         goto err;
0094     }
0095
0096     info.nr_map_ids = 1;
0097     info.map_ids = (__u64)(unsigned long)map_ids;
0098
0099     if (bpf_obj_get_info_by_fd(prog_fd, &info, &info_len)) {
0100         log_err("Failed to get info by prog fd %d", prog_fd);
0101         goto err;
0102     }
0103
0104     if (!info.nr_map_ids) {
0105         log_err("No maps found for prog fd %d", prog_fd);
0106         goto err;
0107     }
0108
0109     *xdp = info.type == BPF_PROG_TYPE_XDP;
0110
0111     map_fd = bpf_map_get_fd_by_id(map_ids[0]);
0112     if (map_fd < 0)
0113         log_err("Failed to get fd by map id %d", map_ids[0]);
0114 err:
0115     if (prog_fd >= 0)
0116         close(prog_fd);
0117     return map_fd;
0118 }
0119
0120 static int run_test(int server_fd, int results_fd, bool xdp,
0121             const struct sockaddr *addr, socklen_t len)
0122 {
0123     int client = -1, srv_client = -1;
0124     int ret = 0;
0125     __u32 key = 0;
0126     __u32 key_gen = 1;
0127     __u32 key_mss = 2;
0128     __u32 value = 0;
0129     __u32 value_gen = 0;
0130     __u32 value_mss = 0;
0131
0132     if (bpf_map_update_elem(results_fd, &key, &value, 0) < 0) {
0133         log_err("Can't clear results");
0134         goto err;
0135     }
0136
0137     if (bpf_map_update_elem(results_fd, &key_gen, &value_gen, 0) < 0) {
0138         log_err("Can't clear results");
0139         goto err;
0140     }
0141
0142     if (bpf_map_update_elem(results_fd, &key_mss, &value_mss, 0) < 0) {
0143         log_err("Can't clear results");
0144         goto err;
0145     }
0146
0147     client = connect_to_server(addr, len);
0148     if (client == -1)
0149         goto err;
0150
0151     srv_client = accept(server_fd, NULL, 0);
0152     if (srv_client == -1) {
0153         log_err("Can't accept connection");
0154         goto err;
0155     }
0156
0157     if (bpf_map_lookup_elem(results_fd, &key, &value) < 0) {
0158         log_err("Can't lookup result");
0159         goto err;
0160     }
0161
0162     if (value == 0) {
0163         log_err("Didn't match syncookie: %u", value);
0164         goto err;
0165     }
0166
0167     if (bpf_map_lookup_elem(results_fd, &key_gen, &value_gen) < 0) {
0168         log_err("Can't lookup result");
0169         goto err;
0170     }
0171
0172     if (xdp && value_gen == 0) {
0173         // SYN packets do not get passed through generic XDP, skip the
0174         // rest of the test.
0175         printf("Skipping XDP cookie check\n");
0176         goto out;
0177     }
0178
0179     if (bpf_map_lookup_elem(results_fd, &key_mss, &value_mss) < 0) {
0180         log_err("Can't lookup result");
0181         goto err;
0182     }
0183
0184     if (value != value_gen) {
0185         log_err("BPF generated cookie does not match kernel one");
0186         goto err;
0187     }
0188
0189     if (value_mss < 536 || value_mss > USHRT_MAX) {
0190         log_err("Unexpected MSS retrieved");
0191         goto err;
0192     }
0193
0194     goto out;
0195
0196 err:
0197     ret = 1;
0198 out:
0199     close(client);
0200     close(srv_client);
0201     return ret;
0202 }
0203
0204 static bool get_port(int server_fd, in_port_t *port)
0205 {
0206     struct sockaddr_in addr;
0207     socklen_t len = sizeof(addr);
0208
0209     if (getsockname(server_fd, (struct sockaddr *)&addr, &len)) {
0210         log_err("Failed to get server addr");
0211         return false;
0212     }
0213
0214     /* sin_port and sin6_port are located at the same offset. */
0215     *port = addr.sin_port;
0216     return true;
0217 }
0218
0219 int main(int argc, char **argv)
0220 {
0221     struct sockaddr_in addr4;
0222     struct sockaddr_in6 addr6;
0223     struct sockaddr_in addr4dual;
0224     struct sockaddr_in6 addr6dual;
0225     int server = -1;
0226     int server_v6 = -1;
0227     int server_dual = -1;
0228     int results = -1;
0229     int err = 0;
0230     bool xdp;
0231
0232     if (argc < 2) {
0233         fprintf(stderr, "Usage: %s prog_id\n", argv[0]);
0234         exit(1);
0235     }
0236
0237     /* Use libbpf 1.0 API mode */
0238     libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
0239
0240     results = get_map_fd_by_prog_id(atoi(argv[1]), &xdp);
0241     if (results < 0) {
0242         log_err("Can't get map");
0243         goto err;
0244     }
0245
0246     memset(&addr4, 0, sizeof(addr4));
0247     addr4.sin_family = AF_INET;
0248     addr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
0249     addr4.sin_port = 0;
0250     memcpy(&addr4dual, &addr4, sizeof(addr4dual));
0251
0252     memset(&addr6, 0, sizeof(addr6));
0253     addr6.sin6_family = AF_INET6;
0254     addr6.sin6_addr = in6addr_loopback;
0255     addr6.sin6_port = 0;
0256
0257     memset(&addr6dual, 0, sizeof(addr6dual));
0258     addr6dual.sin6_family = AF_INET6;
0259     addr6dual.sin6_addr = in6addr_any;
0260     addr6dual.sin6_port = 0;
0261
0262     server = start_server((const struct sockaddr *)&addr4, sizeof(addr4),
0263                   false);
0264     if (server == -1 || !get_port(server, &addr4.sin_port))
0265         goto err;
0266
0267     server_v6 = start_server((const struct sockaddr *)&addr6,
0268                  sizeof(addr6), false);
0269     if (server_v6 == -1 || !get_port(server_v6, &addr6.sin6_port))
0270         goto err;
0271
0272     server_dual = start_server((const struct sockaddr *)&addr6dual,
0273                    sizeof(addr6dual), true);
0274     if (server_dual == -1 || !get_port(server_dual, &addr4dual.sin_port))
0275         goto err;
0276
0277     if (run_test(server, results, xdp,
0278              (const struct sockaddr *)&addr4, sizeof(addr4)))
0279         goto err;
0280
0281     if (run_test(server_v6, results, xdp,
0282              (const struct sockaddr *)&addr6, sizeof(addr6)))
0283         goto err;
0284
0285     if (run_test(server_dual, results, xdp,
0286              (const struct sockaddr *)&addr4dual, sizeof(addr4dual)))
0287         goto err;
0288
0289     printf("ok\n");
0290     goto out;
0291 err:
0292     err = 1;
0293 out:
0294     close(server);
0295     close(server_v6);
0296     close(server_dual);
0297     close(results);
0298     return err;
0299 }