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 memcpy(ifr.ifr_name, dev_name, IFNAMSIZ);
51
52 err = ioctl(fd, TUNSETIFF, &ifr);
53 if (!ASSERT_OK(err, "ioctl(TUNSETIFF)")) {
54 close(fd);
55 return -1;
56 }
57
58 err = fcntl(fd, F_SETFL, O_NONBLOCK);
59 if (!ASSERT_OK(err, "fcntl(O_NONBLOCK)")) {
60 close(fd);
61 return -1;
62 }
63
64 return fd;
65 }
66
67 #define ICMP_PAYLOAD_SIZE 100
68
69 /* Match an ICMP packet with payload len ICMP_PAYLOAD_SIZE */
__expect_icmp_ipv4(char * buf,ssize_t len)70 static int __expect_icmp_ipv4(char *buf, ssize_t len)
71 {
72 struct iphdr *ip = (struct iphdr *)buf;
73 struct icmphdr *icmp = (struct icmphdr *)(ip + 1);
74 ssize_t min_header_len = sizeof(*ip) + sizeof(*icmp);
75
76 if (len < min_header_len)
77 return -1;
78
79 if (ip->protocol != IPPROTO_ICMP)
80 return -1;
81
82 if (icmp->type != ICMP_ECHO)
83 return -1;
84
85 return len == ICMP_PAYLOAD_SIZE + min_header_len;
86 }
87
88 typedef int (*filter_t) (char *, ssize_t);
89
90 /* wait_for_packet - wait for a packet that matches the filter
91 *
92 * @fd: tun fd/packet socket to read packet
93 * @filter: filter function, returning 1 if matches
94 * @timeout: timeout to wait for the packet
95 *
96 * Returns 1 if a matching packet is read, 0 if timeout expired, -1 on error.
97 */
wait_for_packet(int fd,filter_t filter,struct timeval * timeout)98 static int wait_for_packet(int fd, filter_t filter, struct timeval *timeout)
99 {
100 char buf[4096];
101 int max_retry = 5; /* in case we read some spurious packets */
102 fd_set fds;
103
104 FD_ZERO(&fds);
105 while (max_retry--) {
106 /* Linux modifies timeout arg... So make a copy */
107 struct timeval copied_timeout = *timeout;
108 ssize_t ret = -1;
109
110 FD_SET(fd, &fds);
111
112 ret = select(1 + fd, &fds, NULL, NULL, &copied_timeout);
113 if (ret <= 0) {
114 if (errno == EINTR)
115 continue;
116 else if (errno == EAGAIN || ret == 0)
117 return 0;
118
119 log_err("select failed");
120 return -1;
121 }
122
123 ret = read(fd, buf, sizeof(buf));
124
125 if (ret <= 0) {
126 log_err("read(dev): %ld", ret);
127 return -1;
128 }
129
130 if (filter && filter(buf, ret) > 0)
131 return 1;
132 }
133
134 return 0;
135 }
136
137 #endif /* __LWT_HELPERS_H */
138