lwt_helpers.h

  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/icmp.h>
  9
 10#include "test_progs.h"
 11
 12#define log_err(MSG, ...) \
 13	fprintf(stderr, "(%s:%d: errno: %s) " MSG "\n", \
 14		__FILE__, __LINE__, strerror(errno), ##__VA_ARGS__)
 15
 16#define RUN_TEST(name)                                                        \
 17	({                                                                    \
 18		if (test__start_subtest(#name))                               \
 19			if (ASSERT_OK(netns_create(), "netns_create")) {      \
 20				struct nstoken *token = open_netns(NETNS);    \
 21				if (ASSERT_OK_PTR(token, "setns")) {          \
 22					test_ ## name();                      \
 23					close_netns(token);                   \
 24				}                                             \
 25				netns_delete();                               \
 26			}                                                     \
 27	})
 28
 29static inline int netns_create(void)
 30{
 31	return system("ip netns add " NETNS);
 32}
 33
 34static inline int netns_delete(void)
 35{
 36	return system("ip netns del " NETNS ">/dev/null 2>&1");
 37}
 38
 39#define ICMP_PAYLOAD_SIZE     100
 40
 41/* Match an ICMP packet with payload len ICMP_PAYLOAD_SIZE */
 42static int __expect_icmp_ipv4(char *buf, ssize_t len)
 43{
 44	struct iphdr *ip = (struct iphdr *)buf;
 45	struct icmphdr *icmp = (struct icmphdr *)(ip + 1);
 46	ssize_t min_header_len = sizeof(*ip) + sizeof(*icmp);
 47
 48	if (len < min_header_len)
 49		return -1;
 50
 51	if (ip->protocol != IPPROTO_ICMP)
 52		return -1;
 53
 54	if (icmp->type != ICMP_ECHO)
 55		return -1;
 56
 57	return len == ICMP_PAYLOAD_SIZE + min_header_len;
 58}
 59
 60typedef int (*filter_t) (char *, ssize_t);
 61
 62/* wait_for_packet - wait for a packet that matches the filter
 63 *
 64 * @fd: tun fd/packet socket to read packet
 65 * @filter: filter function, returning 1 if matches
 66 * @timeout: timeout to wait for the packet
 67 *
 68 * Returns 1 if a matching packet is read, 0 if timeout expired, -1 on error.
 69 */
 70static int wait_for_packet(int fd, filter_t filter, struct timeval *timeout)
 71{
 72	char buf[4096];
 73	int max_retry = 5; /* in case we read some spurious packets */
 74	fd_set fds;
 75
 76	FD_ZERO(&fds);
 77	while (max_retry--) {
 78		/* Linux modifies timeout arg... So make a copy */
 79		struct timeval copied_timeout = *timeout;
 80		ssize_t ret = -1;
 81
 82		FD_SET(fd, &fds);
 83
 84		ret = select(1 + fd, &fds, NULL, NULL, &copied_timeout);
 85		if (ret <= 0) {
 86			if (errno == EINTR)
 87				continue;
 88			else if (errno == EAGAIN || ret == 0)
 89				return 0;
 90
 91			log_err("select failed");
 92			return -1;
 93		}
 94
 95		ret = read(fd, buf, sizeof(buf));
 96
 97		if (ret <= 0) {
 98			log_err("read(dev): %ld", ret);
 99			return -1;
100		}
101
102		if (filter && filter(buf, ret) > 0)
103			return 1;
104	}
105
106	return 0;
107}
108
109#endif /* __LWT_HELPERS_H */