selftests/bpf/test_skb_cgroup_id_user.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 // Copyright (c) 2018 Facebook
0003
0004 #include <stdlib.h>
0005 #include <string.h>
0006 #include <unistd.h>
0007
0008 #include <arpa/inet.h>
0009 #include <net/if.h>
0010 #include <netinet/in.h>
0011 #include <sys/socket.h>
0012 #include <sys/types.h>
0013
0014
0015 #include <bpf/bpf.h>
0016 #include <bpf/libbpf.h>
0017
0018 #include "cgroup_helpers.h"
0019
0020 #define CGROUP_PATH     "/skb_cgroup_test"
0021 #define NUM_CGROUP_LEVELS   4
0022
0023 /* RFC 4291, Section 2.7.1 */
0024 #define LINKLOCAL_MULTICAST "ff02::1"
0025
0026 static int mk_dst_addr(const char *ip, const char *iface,
0027                struct sockaddr_in6 *dst)
0028 {
0029     memset(dst, 0, sizeof(*dst));
0030
0031     dst->sin6_family = AF_INET6;
0032     dst->sin6_port = htons(1025);
0033
0034     if (inet_pton(AF_INET6, ip, &dst->sin6_addr) != 1) {
0035         log_err("Invalid IPv6: %s", ip);
0036         return -1;
0037     }
0038
0039     dst->sin6_scope_id = if_nametoindex(iface);
0040     if (!dst->sin6_scope_id) {
0041         log_err("Failed to get index of iface: %s", iface);
0042         return -1;
0043     }
0044
0045     return 0;
0046 }
0047
0048 static int send_packet(const char *iface)
0049 {
0050     struct sockaddr_in6 dst;
0051     char msg[] = "msg";
0052     int err = 0;
0053     int fd = -1;
0054
0055     if (mk_dst_addr(LINKLOCAL_MULTICAST, iface, &dst))
0056         goto err;
0057
0058     fd = socket(AF_INET6, SOCK_DGRAM, 0);
0059     if (fd == -1) {
0060         log_err("Failed to create UDP socket");
0061         goto err;
0062     }
0063
0064     if (sendto(fd, &msg, sizeof(msg), 0, (const struct sockaddr *)&dst,
0065            sizeof(dst)) == -1) {
0066         log_err("Failed to send datagram");
0067         goto err;
0068     }
0069
0070     goto out;
0071 err:
0072     err = -1;
0073 out:
0074     if (fd >= 0)
0075         close(fd);
0076     return err;
0077 }
0078
0079 int get_map_fd_by_prog_id(int prog_id)
0080 {
0081     struct bpf_prog_info info = {};
0082     __u32 info_len = sizeof(info);
0083     __u32 map_ids[1];
0084     int prog_fd = -1;
0085     int map_fd = -1;
0086
0087     prog_fd = bpf_prog_get_fd_by_id(prog_id);
0088     if (prog_fd < 0) {
0089         log_err("Failed to get fd by prog id %d", prog_id);
0090         goto err;
0091     }
0092
0093     info.nr_map_ids = 1;
0094     info.map_ids = (__u64) (unsigned long) map_ids;
0095
0096     if (bpf_obj_get_info_by_fd(prog_fd, &info, &info_len)) {
0097         log_err("Failed to get info by prog fd %d", prog_fd);
0098         goto err;
0099     }
0100
0101     if (!info.nr_map_ids) {
0102         log_err("No maps found for prog fd %d", prog_fd);
0103         goto err;
0104     }
0105
0106     map_fd = bpf_map_get_fd_by_id(map_ids[0]);
0107     if (map_fd < 0)
0108         log_err("Failed to get fd by map id %d", map_ids[0]);
0109 err:
0110     if (prog_fd >= 0)
0111         close(prog_fd);
0112     return map_fd;
0113 }
0114
0115 int check_ancestor_cgroup_ids(int prog_id)
0116 {
0117     __u64 actual_ids[NUM_CGROUP_LEVELS], expected_ids[NUM_CGROUP_LEVELS];
0118     __u32 level;
0119     int err = 0;
0120     int map_fd;
0121
0122     expected_ids[0] = get_cgroup_id("/.."); /* root cgroup */
0123     expected_ids[1] = get_cgroup_id("");
0124     expected_ids[2] = get_cgroup_id(CGROUP_PATH);
0125     expected_ids[3] = 0; /* non-existent cgroup */
0126
0127     map_fd = get_map_fd_by_prog_id(prog_id);
0128     if (map_fd < 0)
0129         goto err;
0130
0131     for (level = 0; level < NUM_CGROUP_LEVELS; ++level) {
0132         if (bpf_map_lookup_elem(map_fd, &level, &actual_ids[level])) {
0133             log_err("Failed to lookup key %d", level);
0134             goto err;
0135         }
0136         if (actual_ids[level] != expected_ids[level]) {
0137             log_err("%llx (actual) != %llx (expected), level: %u\n",
0138                 actual_ids[level], expected_ids[level], level);
0139             goto err;
0140         }
0141     }
0142
0143     goto out;
0144 err:
0145     err = -1;
0146 out:
0147     if (map_fd >= 0)
0148         close(map_fd);
0149     return err;
0150 }
0151
0152 int main(int argc, char **argv)
0153 {
0154     int cgfd = -1;
0155     int err = 0;
0156
0157     if (argc < 3) {
0158         fprintf(stderr, "Usage: %s iface prog_id\n", argv[0]);
0159         exit(EXIT_FAILURE);
0160     }
0161
0162     /* Use libbpf 1.0 API mode */
0163     libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
0164
0165     cgfd = cgroup_setup_and_join(CGROUP_PATH);
0166     if (cgfd < 0)
0167         goto err;
0168
0169     if (send_packet(argv[1]))
0170         goto err;
0171
0172     if (check_ancestor_cgroup_ids(atoi(argv[2])))
0173         goto err;
0174
0175     goto out;
0176 err:
0177     err = -1;
0178 out:
0179     close(cgfd);
0180     cleanup_cgroup_environment();
0181     printf("[%s]\n", err ? "FAIL" : "PASS");
0182     return err;
0183 }