1 | // SPDX-License-Identifier: GPL-2.0 |
2 | // Copyright (c) 2018 Facebook |
3 | |
4 | #include <stdlib.h> |
5 | #include <string.h> |
6 | #include <unistd.h> |
7 | |
8 | #include <arpa/inet.h> |
9 | #include <net/if.h> |
10 | #include <netinet/in.h> |
11 | #include <sys/socket.h> |
12 | #include <sys/types.h> |
13 | |
14 | |
15 | #include <bpf/bpf.h> |
16 | #include <bpf/libbpf.h> |
17 | |
18 | #include "cgroup_helpers.h" |
19 | |
20 | #define CGROUP_PATH "/skb_cgroup_test" |
21 | #define NUM_CGROUP_LEVELS 4 |
22 | |
23 | /* RFC 4291, Section 2.7.1 */ |
24 | #define LINKLOCAL_MULTICAST "ff02::1" |
25 | |
26 | static int mk_dst_addr(const char *ip, const char *iface, |
27 | struct sockaddr_in6 *dst) |
28 | { |
29 | memset(dst, 0, sizeof(*dst)); |
30 | |
31 | dst->sin6_family = AF_INET6; |
32 | dst->sin6_port = htons(1025); |
33 | |
34 | if (inet_pton(AF_INET6, ip, &dst->sin6_addr) != 1) { |
35 | log_err("Invalid IPv6: %s" , ip); |
36 | return -1; |
37 | } |
38 | |
39 | dst->sin6_scope_id = if_nametoindex(iface); |
40 | if (!dst->sin6_scope_id) { |
41 | log_err("Failed to get index of iface: %s" , iface); |
42 | return -1; |
43 | } |
44 | |
45 | return 0; |
46 | } |
47 | |
48 | static int send_packet(const char *iface) |
49 | { |
50 | struct sockaddr_in6 dst; |
51 | char msg[] = "msg" ; |
52 | int err = 0; |
53 | int fd = -1; |
54 | |
55 | if (mk_dst_addr(LINKLOCAL_MULTICAST, iface, dst: &dst)) |
56 | goto err; |
57 | |
58 | fd = socket(AF_INET6, SOCK_DGRAM, 0); |
59 | if (fd == -1) { |
60 | log_err("Failed to create UDP socket" ); |
61 | goto err; |
62 | } |
63 | |
64 | if (sendto(fd, &msg, sizeof(msg), 0, (const struct sockaddr *)&dst, |
65 | sizeof(dst)) == -1) { |
66 | log_err("Failed to send datagram" ); |
67 | goto err; |
68 | } |
69 | |
70 | goto out; |
71 | err: |
72 | err = -1; |
73 | out: |
74 | if (fd >= 0) |
75 | close(fd); |
76 | return err; |
77 | } |
78 | |
79 | int get_map_fd_by_prog_id(int prog_id) |
80 | { |
81 | struct bpf_prog_info info = {}; |
82 | __u32 info_len = sizeof(info); |
83 | __u32 map_ids[1]; |
84 | int prog_fd = -1; |
85 | int map_fd = -1; |
86 | |
87 | prog_fd = bpf_prog_get_fd_by_id(prog_id); |
88 | if (prog_fd < 0) { |
89 | log_err("Failed to get fd by prog id %d" , prog_id); |
90 | goto err; |
91 | } |
92 | |
93 | info.nr_map_ids = 1; |
94 | info.map_ids = (__u64) (unsigned long) map_ids; |
95 | |
96 | if (bpf_prog_get_info_by_fd(prog_fd, &info, &info_len)) { |
97 | log_err("Failed to get info by prog fd %d" , prog_fd); |
98 | goto err; |
99 | } |
100 | |
101 | if (!info.nr_map_ids) { |
102 | log_err("No maps found for prog fd %d" , prog_fd); |
103 | goto err; |
104 | } |
105 | |
106 | map_fd = bpf_map_get_fd_by_id(map_ids[0]); |
107 | if (map_fd < 0) |
108 | log_err("Failed to get fd by map id %d" , map_ids[0]); |
109 | err: |
110 | if (prog_fd >= 0) |
111 | close(prog_fd); |
112 | return map_fd; |
113 | } |
114 | |
115 | int check_ancestor_cgroup_ids(int prog_id) |
116 | { |
117 | __u64 actual_ids[NUM_CGROUP_LEVELS], expected_ids[NUM_CGROUP_LEVELS]; |
118 | __u32 level; |
119 | int err = 0; |
120 | int map_fd; |
121 | |
122 | expected_ids[0] = get_cgroup_id("/.." ); /* root cgroup */ |
123 | expected_ids[1] = get_cgroup_id("" ); |
124 | expected_ids[2] = get_cgroup_id(CGROUP_PATH); |
125 | expected_ids[3] = 0; /* non-existent cgroup */ |
126 | |
127 | map_fd = get_map_fd_by_prog_id(prog_id); |
128 | if (map_fd < 0) |
129 | goto err; |
130 | |
131 | for (level = 0; level < NUM_CGROUP_LEVELS; ++level) { |
132 | if (bpf_map_lookup_elem(map_fd, &level, &actual_ids[level])) { |
133 | log_err("Failed to lookup key %d" , level); |
134 | goto err; |
135 | } |
136 | if (actual_ids[level] != expected_ids[level]) { |
137 | log_err("%llx (actual) != %llx (expected), level: %u\n" , |
138 | actual_ids[level], expected_ids[level], level); |
139 | goto err; |
140 | } |
141 | } |
142 | |
143 | goto out; |
144 | err: |
145 | err = -1; |
146 | out: |
147 | if (map_fd >= 0) |
148 | close(map_fd); |
149 | return err; |
150 | } |
151 | |
152 | int main(int argc, char **argv) |
153 | { |
154 | int cgfd = -1; |
155 | int err = 0; |
156 | |
157 | if (argc < 3) { |
158 | fprintf(stderr, "Usage: %s iface prog_id\n" , argv[0]); |
159 | exit(EXIT_FAILURE); |
160 | } |
161 | |
162 | /* Use libbpf 1.0 API mode */ |
163 | libbpf_set_strict_mode(LIBBPF_STRICT_ALL); |
164 | |
165 | cgfd = cgroup_setup_and_join(CGROUP_PATH); |
166 | if (cgfd < 0) |
167 | goto err; |
168 | |
169 | if (send_packet(iface: argv[1])) |
170 | goto err; |
171 | |
172 | if (check_ancestor_cgroup_ids(prog_id: atoi(argv[2]))) |
173 | goto err; |
174 | |
175 | goto out; |
176 | err: |
177 | err = -1; |
178 | out: |
179 | close(cgfd); |
180 | cleanup_cgroup_environment(); |
181 | printf("[%s]\n" , err ? "FAIL" : "PASS" ); |
182 | return err; |
183 | } |
184 | |