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
netns_create(void)30 static inline int netns_create(void)
31 {
32 return system("ip netns add " NETNS);
33 }
34
netns_delete(void)35 static inline int netns_delete(void)
36 {
37 return system("ip netns del " NETNS ">/dev/null 2>&1");
38 }
39
open_tuntap(const char * dev_name,bool need_mac)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 */
__expect_icmp_ipv4(char * buf,ssize_t len)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 */
wait_for_packet(int fd,filter_t filter,struct timeval * timeout)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 */
139