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 	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 */
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  */
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