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
 26static 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
 48static 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))
 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;
 71err:
 72	err = -1;
 73out:
 74	if (fd >= 0)
 75		close(fd);
 76	return err;
 77}
 78
 79int 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]);
109err:
110	if (prog_fd >= 0)
111		close(prog_fd);
112	return map_fd;
113}
114
115int 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;
144err:
145	err = -1;
146out:
147	if (map_fd >= 0)
148		close(map_fd);
149	return err;
150}
151
152int 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(argv[1]))
170		goto err;
171
172	if (check_ancestor_cgroup_ids(atoi(argv[2])))
173		goto err;
174
175	goto out;
176err:
177	err = -1;
178out:
179	close(cgfd);
180	cleanup_cgroup_environment();
181	printf("[%s]\n", err ? "FAIL" : "PASS");
182	return err;
183}