139 lines · c
1/* SPDX-License-Identifier: GPL-2.0 */2 3#ifndef __LWT_HELPERS_H4#define __LWT_HELPERS_H5 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 10069 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 filter92 *93 * @fd: tun fd/packet socket to read packet94 * @filter: filter function, returning 1 if matches95 * @timeout: timeout to wait for the packet96 *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 */139