1 // SPDX-License-Identifier: GPL-2.0
2 /* Test IPV6_FLOWINFO cmsg on send and recv */
3 
4 #define _GNU_SOURCE
5 
6 #include <arpa/inet.h>
7 #include <asm/byteorder.h>
8 #include <error.h>
9 #include <errno.h>
10 #include <fcntl.h>
11 #include <limits.h>
12 #include <linux/icmpv6.h>
13 #include <linux/in6.h>
14 #include <stdbool.h>
15 #include <stdio.h>
16 #include <stdint.h>
17 #include <stdlib.h>
18 #include <string.h>
19 #include <sys/socket.h>
20 #include <sys/stat.h>
21 #include <sys/time.h>
22 #include <sys/types.h>
23 #include <unistd.h>
24 
25 /* uapi/glibc weirdness may leave this undefined */
26 #ifndef IPV6_FLOWINFO
27 #define IPV6_FLOWINFO 11
28 #endif
29 
30 #ifndef IPV6_FLOWLABEL_MGR
31 #define IPV6_FLOWLABEL_MGR 32
32 #endif
33 #ifndef IPV6_FLOWINFO_SEND
34 #define IPV6_FLOWINFO_SEND 33
35 #endif
36 
37 #define FLOWLABEL_WILDCARD	((uint32_t) -1)
38 
39 static const char cfg_data[]	= "a";
40 static uint32_t cfg_label	= 1;
41 static bool use_ping;
42 static bool use_flowinfo_send;
43 
44 static struct icmp6hdr icmp6 = {
45 	.icmp6_type = ICMPV6_ECHO_REQUEST
46 };
47 
48 static struct sockaddr_in6 addr = {
49 	.sin6_family = AF_INET6,
50 	.sin6_addr = IN6ADDR_LOOPBACK_INIT,
51 };
52 
do_send(int fd,bool with_flowlabel,uint32_t flowlabel)53 static void do_send(int fd, bool with_flowlabel, uint32_t flowlabel)
54 {
55 	char control[CMSG_SPACE(sizeof(flowlabel))] = {0};
56 	struct msghdr msg = {0};
57 	struct iovec iov = {
58 		.iov_base = (char *)cfg_data,
59 		.iov_len = sizeof(cfg_data)
60 	};
61 	int ret;
62 
63 	if (use_ping) {
64 		iov.iov_base = &icmp6;
65 		iov.iov_len = sizeof(icmp6);
66 	}
67 
68 	msg.msg_iov = &iov;
69 	msg.msg_iovlen = 1;
70 
71 	if (use_flowinfo_send) {
72 		msg.msg_name = &addr;
73 		msg.msg_namelen = sizeof(addr);
74 	} else if (with_flowlabel) {
75 		struct cmsghdr *cm;
76 
77 		cm = (void *)control;
78 		cm->cmsg_len = CMSG_LEN(sizeof(flowlabel));
79 		cm->cmsg_level = SOL_IPV6;
80 		cm->cmsg_type = IPV6_FLOWINFO;
81 		*(uint32_t *)CMSG_DATA(cm) = htonl(flowlabel);
82 
83 		msg.msg_control = control;
84 		msg.msg_controllen = sizeof(control);
85 	}
86 
87 	ret = sendmsg(fd, &msg, 0);
88 	if (ret == -1)
89 		error(1, errno, "send");
90 
91 	if (with_flowlabel)
92 		fprintf(stderr, "sent with label %u\n", flowlabel);
93 	else
94 		fprintf(stderr, "sent without label\n");
95 }
96 
do_recv(int fd,bool with_flowlabel,uint32_t expect)97 static void do_recv(int fd, bool with_flowlabel, uint32_t expect)
98 {
99 	char control[CMSG_SPACE(sizeof(expect))];
100 	char data[sizeof(cfg_data)];
101 	struct msghdr msg = {0};
102 	struct iovec iov = {0};
103 	struct cmsghdr *cm;
104 	uint32_t flowlabel;
105 	int ret;
106 
107 	iov.iov_base = data;
108 	iov.iov_len = sizeof(data);
109 
110 	msg.msg_iov = &iov;
111 	msg.msg_iovlen = 1;
112 
113 	memset(control, 0, sizeof(control));
114 	msg.msg_control = control;
115 	msg.msg_controllen = sizeof(control);
116 
117 	ret = recvmsg(fd, &msg, 0);
118 	if (ret == -1)
119 		error(1, errno, "recv");
120 	if (use_ping)
121 		goto parse_cmsg;
122 	if (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))
123 		error(1, 0, "recv: truncated");
124 	if (ret != sizeof(cfg_data))
125 		error(1, 0, "recv: length mismatch");
126 	if (memcmp(data, cfg_data, sizeof(data)))
127 		error(1, 0, "recv: data mismatch");
128 
129 parse_cmsg:
130 	cm = CMSG_FIRSTHDR(&msg);
131 	if (with_flowlabel) {
132 		if (!cm)
133 			error(1, 0, "recv: missing cmsg");
134 		if (CMSG_NXTHDR(&msg, cm))
135 			error(1, 0, "recv: too many cmsg");
136 		if (cm->cmsg_level != SOL_IPV6 ||
137 		    cm->cmsg_type != IPV6_FLOWINFO)
138 			error(1, 0, "recv: unexpected cmsg level or type");
139 
140 		flowlabel = ntohl(*(uint32_t *)CMSG_DATA(cm));
141 		fprintf(stderr, "recv with label %u\n", flowlabel);
142 
143 		if (expect != FLOWLABEL_WILDCARD && expect != flowlabel) {
144 			fprintf(stderr, "recv: incorrect flowlabel %u != %u\n",
145 					flowlabel, expect);
146 			error(1, 0, "recv: flowlabel is wrong");
147 		}
148 
149 	} else {
150 		fprintf(stderr, "recv without label\n");
151 	}
152 }
153 
get_autoflowlabel_enabled(void)154 static bool get_autoflowlabel_enabled(void)
155 {
156 	int fd, ret;
157 	char val;
158 
159 	fd = open("/proc/sys/net/ipv6/auto_flowlabels", O_RDONLY);
160 	if (fd == -1)
161 		error(1, errno, "open sysctl");
162 
163 	ret = read(fd, &val, 1);
164 	if (ret == -1)
165 		error(1, errno, "read sysctl");
166 	if (ret == 0)
167 		error(1, 0, "read sysctl: 0");
168 
169 	if (close(fd))
170 		error(1, errno, "close sysctl");
171 
172 	return val == '1';
173 }
174 
flowlabel_get(int fd,uint32_t label,uint8_t share,uint16_t flags)175 static void flowlabel_get(int fd, uint32_t label, uint8_t share, uint16_t flags)
176 {
177 	struct in6_flowlabel_req req = {
178 		.flr_action = IPV6_FL_A_GET,
179 		.flr_label = htonl(label),
180 		.flr_flags = flags,
181 		.flr_share = share,
182 	};
183 
184 	/* do not pass IPV6_ADDR_ANY or IPV6_ADDR_MAPPED */
185 	req.flr_dst.s6_addr[0] = 0xfd;
186 	req.flr_dst.s6_addr[15] = 0x1;
187 
188 	if (setsockopt(fd, SOL_IPV6, IPV6_FLOWLABEL_MGR, &req, sizeof(req)))
189 		error(1, errno, "setsockopt flowlabel get");
190 }
191 
parse_opts(int argc,char ** argv)192 static void parse_opts(int argc, char **argv)
193 {
194 	int c;
195 
196 	while ((c = getopt(argc, argv, "l:ps")) != -1) {
197 		switch (c) {
198 		case 'l':
199 			cfg_label = strtoul(optarg, NULL, 0);
200 			break;
201 		case 'p':
202 			use_ping = true;
203 			break;
204 		case 's':
205 			use_flowinfo_send = true;
206 			break;
207 		default:
208 			error(1, 0, "%s: parse error", argv[0]);
209 		}
210 	}
211 }
212 
main(int argc,char ** argv)213 int main(int argc, char **argv)
214 {
215 	const int one = 1;
216 	int fdt, fdr;
217 	int prot = 0;
218 
219 	addr.sin6_port = htons(8000);
220 
221 	parse_opts(argc, argv);
222 
223 	if (use_ping) {
224 		fprintf(stderr, "attempting to use ping sockets\n");
225 		prot = IPPROTO_ICMPV6;
226 	}
227 
228 	fdt = socket(PF_INET6, SOCK_DGRAM, prot);
229 	if (fdt == -1)
230 		error(1, errno, "socket t");
231 
232 	fdr = use_ping ? fdt : socket(PF_INET6, SOCK_DGRAM, 0);
233 	if (fdr == -1)
234 		error(1, errno, "socket r");
235 
236 	if (connect(fdt, (void *)&addr, sizeof(addr)))
237 		error(1, errno, "connect");
238 	if (!use_ping && bind(fdr, (void *)&addr, sizeof(addr)))
239 		error(1, errno, "bind");
240 
241 	flowlabel_get(fdt, cfg_label, IPV6_FL_S_EXCL, IPV6_FL_F_CREATE);
242 
243 	if (setsockopt(fdr, SOL_IPV6, IPV6_FLOWINFO, &one, sizeof(one)))
244 		error(1, errno, "setsockopt flowinfo");
245 
246 	if (get_autoflowlabel_enabled()) {
247 		fprintf(stderr, "send no label: recv auto flowlabel\n");
248 		do_send(fdt, false, 0);
249 		do_recv(fdr, true, FLOWLABEL_WILDCARD);
250 	} else {
251 		fprintf(stderr, "send no label: recv no label (auto off)\n");
252 		do_send(fdt, false, 0);
253 		do_recv(fdr, false, 0);
254 	}
255 
256 	if (use_flowinfo_send) {
257 		fprintf(stderr, "using IPV6_FLOWINFO_SEND to send label\n");
258 		addr.sin6_flowinfo = htonl(cfg_label);
259 		if (setsockopt(fdt, SOL_IPV6, IPV6_FLOWINFO_SEND, &one,
260 			       sizeof(one)) == -1)
261 			error(1, errno, "setsockopt flowinfo_send");
262 	}
263 
264 	fprintf(stderr, "send label\n");
265 	do_send(fdt, true, cfg_label);
266 	do_recv(fdr, true, cfg_label);
267 
268 	if (close(fdr))
269 		error(1, errno, "close r");
270 	if (!use_ping && close(fdt))
271 		error(1, errno, "close t");
272 
273 	return 0;
274 }
275