tools/testing/selftests/bpf/prog_tests/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/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 static inline int netns_create(void)
  31 {
  32         return system("ip netns add " NETNS);
  33 }
  34
  35 static inline int netns_delete(void)
  36 {
  37         return system("ip netns del " NETNS ">/dev/null 2>&1");
  38 }
  39
  40 static 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 */
  71 static 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
  89 typedef 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  */
  99 static 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 */