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