1/* SPDX-License-Identifier: GPL-2.0 */
  2
  3#ifndef __LWT_HELPERS_H
  4#define __LWT_HELPERS_H
  5
  6#include <time.h>
  7#include <net/if.h>
  8#include <linux/if_tun.h>
  9#include <linux/icmp.h>
 10
 11#include "test_progs.h"
 12
 13#define log_err(MSG, ...) \
 14	fprintf(stderr, "(%s:%d: errno: %s) " MSG "\n", \
 15		__FILE__, __LINE__, strerror(errno), ##__VA_ARGS__)
 16
 17#define RUN_TEST(name)                                                        \
 18	({                                                                    \
 19		if (test__start_subtest(#name))                               \
 20			if (ASSERT_OK(netns_create(), "netns_create")) {      \
 21				struct nstoken *token = open_netns(NETNS);    \
 22				if (ASSERT_OK_PTR(token, "setns")) {          \
 23					test_ ## name();                      \
 24					close_netns(token);                   \
 25				}                                             \
 26				netns_delete();                               \
 27			}                                                     \
 28	})
 29
 30static inline int netns_create(void)
 31{
 32	return system("ip netns add " NETNS);
 33}
 34
 35static inline int netns_delete(void)
 36{
 37	return system("ip netns del " NETNS ">/dev/null 2>&1");
 38}
 39
 40static int open_tuntap(const char *dev_name, bool need_mac)
 41{
 42	int err = 0;
 43	struct ifreq ifr;
 44	int fd = open("/dev/net/tun", O_RDWR);
 45
 46	if (!ASSERT_GT(fd, 0, "open(/dev/net/tun)"))
 47		return -1;
 48
 49	ifr.ifr_flags = IFF_NO_PI | (need_mac ? IFF_TAP : IFF_TUN);
 50	strncpy(ifr.ifr_name, dev_name, IFNAMSIZ - 1);
 51	ifr.ifr_name[IFNAMSIZ - 1] = '\0';
 52
 53	err = ioctl(fd, TUNSETIFF, &ifr);
 54	if (!ASSERT_OK(err, "ioctl(TUNSETIFF)")) {
 55		close(fd);
 56		return -1;
 57	}
 58
 59	err = fcntl(fd, F_SETFL, O_NONBLOCK);
 60	if (!ASSERT_OK(err, "fcntl(O_NONBLOCK)")) {
 61		close(fd);
 62		return -1;
 63	}
 64
 65	return fd;
 66}
 67
 68#define ICMP_PAYLOAD_SIZE     100
 69
 70/* Match an ICMP packet with payload len ICMP_PAYLOAD_SIZE */
 71static int __expect_icmp_ipv4(char *buf, ssize_t len)
 72{
 73	struct iphdr *ip = (struct iphdr *)buf;
 74	struct icmphdr *icmp = (struct icmphdr *)(ip + 1);
 75	ssize_t min_header_len = sizeof(*ip) + sizeof(*icmp);
 76
 77	if (len < min_header_len)
 78		return -1;
 79
 80	if (ip->protocol != IPPROTO_ICMP)
 81		return -1;
 82
 83	if (icmp->type != ICMP_ECHO)
 84		return -1;
 85
 86	return len == ICMP_PAYLOAD_SIZE + min_header_len;
 87}
 88
 89typedef int (*filter_t) (char *, ssize_t);
 90
 91/* wait_for_packet - wait for a packet that matches the filter
 92 *
 93 * @fd: tun fd/packet socket to read packet
 94 * @filter: filter function, returning 1 if matches
 95 * @timeout: timeout to wait for the packet
 96 *
 97 * Returns 1 if a matching packet is read, 0 if timeout expired, -1 on error.
 98 */
 99static int wait_for_packet(int fd, filter_t filter, struct timeval *timeout)
100{
101	char buf[4096];
102	int max_retry = 5; /* in case we read some spurious packets */
103	fd_set fds;
104
105	FD_ZERO(&fds);
106	while (max_retry--) {
107		/* Linux modifies timeout arg... So make a copy */
108		struct timeval copied_timeout = *timeout;
109		ssize_t ret = -1;
110
111		FD_SET(fd, &fds);
112
113		ret = select(1 + fd, &fds, NULL, NULL, &copied_timeout);
114		if (ret <= 0) {
115			if (errno == EINTR)
116				continue;
117			else if (errno == EAGAIN || ret == 0)
118				return 0;
119
120			log_err("select failed");
121			return -1;
122		}
123
124		ret = read(fd, buf, sizeof(buf));
125
126		if (ret <= 0) {
127			log_err("read(dev): %ld", ret);
128			return -1;
129		}
130
131		if (filter && filter(buf, ret) > 0)
132			return 1;
133	}
134
135	return 0;
136}
137
138#endif /* __LWT_HELPERS_H */