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 30 #define NETNS "ns_lwt" 31 32 static inline int netns_create(void) 33 { 34 return system("ip netns add " NETNS); 35 } 36 37 static inline int netns_delete(void) 38 { 39 return system("ip netns del " NETNS ">/dev/null 2>&1"); 40 } 41 42 static int open_tuntap(const char *dev_name, bool need_mac) 43 { 44 int err = 0; 45 struct ifreq ifr; 46 int fd = open("/dev/net/tun", O_RDWR); 47 48 if (!ASSERT_GT(fd, 0, "open(/dev/net/tun)")) 49 return -1; 50 51 ifr.ifr_flags = IFF_NO_PI | (need_mac ? IFF_TAP : IFF_TUN); 52 strncpy(ifr.ifr_name, dev_name, IFNAMSIZ - 1); 53 ifr.ifr_name[IFNAMSIZ - 1] = '\0'; 54 55 err = ioctl(fd, TUNSETIFF, &ifr); 56 if (!ASSERT_OK(err, "ioctl(TUNSETIFF)")) { 57 close(fd); 58 return -1; 59 } 60 61 err = fcntl(fd, F_SETFL, O_NONBLOCK); 62 if (!ASSERT_OK(err, "fcntl(O_NONBLOCK)")) { 63 close(fd); 64 return -1; 65 } 66 67 return fd; 68 } 69 70 #define ICMP_PAYLOAD_SIZE 100 71 72 /* Match an ICMP packet with payload len ICMP_PAYLOAD_SIZE */ 73 static int __expect_icmp_ipv4(char *buf, ssize_t len) 74 { 75 struct iphdr *ip = (struct iphdr *)buf; 76 struct icmphdr *icmp = (struct icmphdr *)(ip + 1); 77 ssize_t min_header_len = sizeof(*ip) + sizeof(*icmp); 78 79 if (len < min_header_len) 80 return -1; 81 82 if (ip->protocol != IPPROTO_ICMP) 83 return -1; 84 85 if (icmp->type != ICMP_ECHO) 86 return -1; 87 88 return len == ICMP_PAYLOAD_SIZE + min_header_len; 89 } 90 91 typedef int (*filter_t) (char *, ssize_t); 92 93 /* wait_for_packet - wait for a packet that matches the filter 94 * 95 * @fd: tun fd/packet socket to read packet 96 * @filter: filter function, returning 1 if matches 97 * @timeout: timeout to wait for the packet 98 * 99 * Returns 1 if a matching packet is read, 0 if timeout expired, -1 on error. 100 */ 101 static int wait_for_packet(int fd, filter_t filter, struct timeval *timeout) 102 { 103 char buf[4096]; 104 int max_retry = 5; /* in case we read some spurious packets */ 105 fd_set fds; 106 107 FD_ZERO(&fds); 108 while (max_retry--) { 109 /* Linux modifies timeout arg... So make a copy */ 110 struct timeval copied_timeout = *timeout; 111 ssize_t ret = -1; 112 113 FD_SET(fd, &fds); 114 115 ret = select(1 + fd, &fds, NULL, NULL, &copied_timeout); 116 if (ret <= 0) { 117 if (errno == EINTR) 118 continue; 119 else if (errno == EAGAIN || ret == 0) 120 return 0; 121 122 log_err("select failed"); 123 return -1; 124 } 125 126 ret = read(fd, buf, sizeof(buf)); 127 128 if (ret <= 0) { 129 log_err("read(dev): %ld", ret); 130 return -1; 131 } 132 133 if (filter && filter(buf, ret) > 0) 134 return 1; 135 } 136 137 return 0; 138 } 139 140 #endif /* __LWT_HELPERS_H */ 141