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