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