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 "bpf_rlimit.h"
 19#include "cgroup_helpers.h"
 20
 21#define CGROUP_PATH		"/skb_cgroup_test"
 22#define NUM_CGROUP_LEVELS	4
 23
 24/* RFC 4291, Section 2.7.1 */
 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] = 0x100000001;	/* root cgroup */
124	expected_ids[1] = get_cgroup_id("");
125	expected_ids[2] = get_cgroup_id(CGROUP_PATH);
126	expected_ids[3] = 0; /* non-existent cgroup */
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	if (setup_cgroup_environment())
164		goto err;
165
166	cgfd = create_and_get_cgroup(CGROUP_PATH);
167	if (cgfd < 0)
168		goto err;
169
170	if (join_cgroup(CGROUP_PATH))
171		goto err;
172
173	if (send_packet(argv[1]))
174		goto err;
175
176	if (check_ancestor_cgroup_ids(atoi(argv[2])))
177		goto err;
178
179	goto out;
180err:
181	err = -1;
182out:
183	close(cgfd);
184	cleanup_cgroup_environment();
185	printf("[%s]\n", err ? "FAIL" : "PASS");
186	return err;
187}