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1 /*
2  * link_gre.c	gre driver module
3  *
4  *		This program is free software; you can redistribute it and/or
5  *		modify it under the terms of the GNU General Public License
6  *		as published by the Free Software Foundation; either version
7  *		2 of the License, or (at your option) any later version.
8  *
9  * Authors:	Herbert Xu <herbert@gondor.apana.org.au>
10  *
11  */
12 
13 #include <string.h>
14 #include <net/if.h>
15 #include <sys/types.h>
16 #include <sys/socket.h>
17 #include <arpa/inet.h>
18 
19 #include <linux/ip.h>
20 #include <linux/if_tunnel.h>
21 #include "rt_names.h"
22 #include "utils.h"
23 #include "ip_common.h"
24 #include "tunnel.h"
25 
26 static void usage(void) __attribute__((noreturn));
usage(void)27 static void usage(void)
28 {
29 	fprintf(stderr, "Usage: ip link { add | set | change | replace | del } NAME\n");
30 	fprintf(stderr, "          type { gre | gretap } [ remote ADDR ] [ local ADDR ]\n");
31 	fprintf(stderr, "          [ [i|o]seq ] [ [i|o]key KEY ] [ [i|o]csum ]\n");
32 	fprintf(stderr, "          [ ttl TTL ] [ tos TOS ] [ [no]pmtudisc ] [ dev PHYS_DEV ]\n");
33 	fprintf(stderr, "\n");
34 	fprintf(stderr, "Where: NAME := STRING\n");
35 	fprintf(stderr, "       ADDR := { IP_ADDRESS | any }\n");
36 	fprintf(stderr, "       TOS  := { NUMBER | inherit }\n");
37 	fprintf(stderr, "       TTL  := { 1..255 | inherit }\n");
38 	fprintf(stderr, "       KEY  := { DOTTED_QUAD | NUMBER }\n");
39 	exit(-1);
40 }
41 
gre_parse_opt(struct link_util * lu,int argc,char ** argv,struct nlmsghdr * n)42 static int gre_parse_opt(struct link_util *lu, int argc, char **argv,
43 			 struct nlmsghdr *n)
44 {
45 	struct {
46 		struct nlmsghdr n;
47 		struct ifinfomsg i;
48 		char buf[1024];
49 	} req;
50 	struct ifinfomsg *ifi = (struct ifinfomsg *)(n + 1);
51 	struct rtattr *tb[IFLA_MAX + 1];
52 	struct rtattr *linkinfo[IFLA_INFO_MAX+1];
53 	struct rtattr *greinfo[IFLA_GRE_MAX + 1];
54 	__u16 iflags = 0;
55 	__u16 oflags = 0;
56 	unsigned ikey = 0;
57 	unsigned okey = 0;
58 	unsigned saddr = 0;
59 	unsigned daddr = 0;
60 	unsigned link = 0;
61 	__u8 pmtudisc = 1;
62 	__u8 ttl = 0;
63 	__u8 tos = 0;
64 	int len;
65 
66 	if (!(n->nlmsg_flags & NLM_F_CREATE)) {
67 		memset(&req, 0, sizeof(req));
68 
69 		req.n.nlmsg_len = NLMSG_LENGTH(sizeof(*ifi));
70 		req.n.nlmsg_flags = NLM_F_REQUEST;
71 		req.n.nlmsg_type = RTM_GETLINK;
72 		req.i.ifi_family = preferred_family;
73 		req.i.ifi_index = ifi->ifi_index;
74 
75 		if (rtnl_talk(&rth, &req.n, 0, 0, &req.n, NULL, NULL) < 0) {
76 get_failed:
77 			fprintf(stderr,
78 				"Failed to get existing tunnel info.\n");
79 			return -1;
80 		}
81 
82 		len = req.n.nlmsg_len;
83 		len -= NLMSG_LENGTH(sizeof(*ifi));
84 		if (len < 0)
85 			goto get_failed;
86 
87 		parse_rtattr(tb, IFLA_MAX, IFLA_RTA(&req.i), len);
88 
89 		if (!tb[IFLA_LINKINFO])
90 			goto get_failed;
91 
92 		parse_rtattr_nested(linkinfo, IFLA_INFO_MAX, tb[IFLA_LINKINFO]);
93 
94 		if (!linkinfo[IFLA_INFO_DATA])
95 			goto get_failed;
96 
97 		parse_rtattr_nested(greinfo, IFLA_GRE_MAX,
98 				    linkinfo[IFLA_INFO_DATA]);
99 
100 		if (greinfo[IFLA_GRE_IKEY])
101 			ikey = *(__u32 *)RTA_DATA(greinfo[IFLA_GRE_IKEY]);
102 
103 		if (greinfo[IFLA_GRE_OKEY])
104 			okey = *(__u32 *)RTA_DATA(greinfo[IFLA_GRE_OKEY]);
105 
106 		if (greinfo[IFLA_GRE_IFLAGS])
107 			iflags = *(__u16 *)RTA_DATA(greinfo[IFLA_GRE_IFLAGS]);
108 
109 		if (greinfo[IFLA_GRE_OFLAGS])
110 			oflags = *(__u16 *)RTA_DATA(greinfo[IFLA_GRE_OFLAGS]);
111 
112 		if (greinfo[IFLA_GRE_LOCAL])
113 			saddr = *(__u32 *)RTA_DATA(greinfo[IFLA_GRE_LOCAL]);
114 
115 		if (greinfo[IFLA_GRE_REMOTE])
116 			daddr = *(__u32 *)RTA_DATA(greinfo[IFLA_GRE_REMOTE]);
117 
118 		if (greinfo[IFLA_GRE_PMTUDISC])
119 			pmtudisc = *(__u8 *)RTA_DATA(
120 				greinfo[IFLA_GRE_PMTUDISC]);
121 
122 		if (greinfo[IFLA_GRE_TTL])
123 			ttl = *(__u8 *)RTA_DATA(greinfo[IFLA_GRE_TTL]);
124 
125 		if (greinfo[IFLA_GRE_TOS])
126 			tos = *(__u8 *)RTA_DATA(greinfo[IFLA_GRE_TOS]);
127 
128 		if (greinfo[IFLA_GRE_LINK])
129 			link = *(__u8 *)RTA_DATA(greinfo[IFLA_GRE_LINK]);
130 	}
131 
132 	while (argc > 0) {
133 		if (!matches(*argv, "key")) {
134 			unsigned uval;
135 
136 			NEXT_ARG();
137 			iflags |= GRE_KEY;
138 			oflags |= GRE_KEY;
139 			if (strchr(*argv, '.'))
140 				uval = get_addr32(*argv);
141 			else {
142 				if (get_unsigned(&uval, *argv, 0) < 0) {
143 					fprintf(stderr,
144 						"Invalid value for \"key\"\n");
145 					exit(-1);
146 				}
147 				uval = htonl(uval);
148 			}
149 
150 			ikey = okey = uval;
151 		} else if (!matches(*argv, "ikey")) {
152 			unsigned uval;
153 
154 			NEXT_ARG();
155 			iflags |= GRE_KEY;
156 			if (strchr(*argv, '.'))
157 				uval = get_addr32(*argv);
158 			else {
159 				if (get_unsigned(&uval, *argv, 0)<0) {
160 					fprintf(stderr, "invalid value of \"ikey\"\n");
161 					exit(-1);
162 				}
163 				uval = htonl(uval);
164 			}
165 			ikey = uval;
166 		} else if (!matches(*argv, "okey")) {
167 			unsigned uval;
168 
169 			NEXT_ARG();
170 			oflags |= GRE_KEY;
171 			if (strchr(*argv, '.'))
172 				uval = get_addr32(*argv);
173 			else {
174 				if (get_unsigned(&uval, *argv, 0)<0) {
175 					fprintf(stderr, "invalid value of \"okey\"\n");
176 					exit(-1);
177 				}
178 				uval = htonl(uval);
179 			}
180 			okey = uval;
181 		} else if (!matches(*argv, "seq")) {
182 			iflags |= GRE_SEQ;
183 			oflags |= GRE_SEQ;
184 		} else if (!matches(*argv, "iseq")) {
185 			iflags |= GRE_SEQ;
186 		} else if (!matches(*argv, "oseq")) {
187 			oflags |= GRE_SEQ;
188 		} else if (!matches(*argv, "csum")) {
189 			iflags |= GRE_CSUM;
190 			oflags |= GRE_CSUM;
191 		} else if (!matches(*argv, "icsum")) {
192 			iflags |= GRE_CSUM;
193 		} else if (!matches(*argv, "ocsum")) {
194 			oflags |= GRE_CSUM;
195 		} else if (!matches(*argv, "nopmtudisc")) {
196 			pmtudisc = 0;
197 		} else if (!matches(*argv, "pmtudisc")) {
198 			pmtudisc = 1;
199 		} else if (!matches(*argv, "remote")) {
200 			NEXT_ARG();
201 			if (strcmp(*argv, "any"))
202 				daddr = get_addr32(*argv);
203 		} else if (!matches(*argv, "local")) {
204 			NEXT_ARG();
205 			if (strcmp(*argv, "any"))
206 				saddr = get_addr32(*argv);
207 		} else if (!matches(*argv, "dev")) {
208 			NEXT_ARG();
209 			link = tnl_ioctl_get_ifindex(*argv);
210 			if (link == 0)
211 				exit(-1);
212 		} else if (!matches(*argv, "ttl") ||
213 			   !matches(*argv, "hoplimit")) {
214 			unsigned uval;
215 
216 			NEXT_ARG();
217 			if (strcmp(*argv, "inherit") != 0) {
218 				if (get_unsigned(&uval, *argv, 0))
219 					invarg("invalid TTL\n", *argv);
220 				if (uval > 255)
221 					invarg("TTL must be <= 255\n", *argv);
222 				ttl = uval;
223 			}
224 		} else if (!matches(*argv, "tos") ||
225 			   !matches(*argv, "tclass") ||
226 			   !matches(*argv, "dsfield")) {
227 			__u32 uval;
228 
229 			NEXT_ARG();
230 			if (strcmp(*argv, "inherit") != 0) {
231 				if (rtnl_dsfield_a2n(&uval, *argv))
232 					invarg("bad TOS value", *argv);
233 				tos = uval;
234 			} else
235 				tos = 1;
236 		} else
237 			usage();
238 		argc--; argv++;
239 	}
240 
241 	if (!ikey && IN_MULTICAST(ntohl(daddr))) {
242 		ikey = daddr;
243 		iflags |= GRE_KEY;
244 	}
245 	if (!okey && IN_MULTICAST(ntohl(daddr))) {
246 		okey = daddr;
247 		oflags |= GRE_KEY;
248 	}
249 	if (IN_MULTICAST(ntohl(daddr)) && !saddr) {
250 		fprintf(stderr, "Broadcast tunnel requires a source address.\n");
251 		return -1;
252 	}
253 
254 	addattr32(n, 1024, IFLA_GRE_IKEY, ikey);
255 	addattr32(n, 1024, IFLA_GRE_OKEY, okey);
256 	addattr_l(n, 1024, IFLA_GRE_IFLAGS, &iflags, 2);
257 	addattr_l(n, 1024, IFLA_GRE_OFLAGS, &oflags, 2);
258 	addattr_l(n, 1024, IFLA_GRE_LOCAL, &saddr, 4);
259 	addattr_l(n, 1024, IFLA_GRE_REMOTE, &daddr, 4);
260 	addattr_l(n, 1024, IFLA_GRE_PMTUDISC, &pmtudisc, 1);
261 	if (link)
262 		addattr32(n, 1024, IFLA_GRE_LINK, link);
263 	addattr_l(n, 1024, IFLA_GRE_TTL, &ttl, 1);
264 	addattr_l(n, 1024, IFLA_GRE_TOS, &tos, 1);
265 
266 	return 0;
267 }
268 
gre_print_opt(struct link_util * lu,FILE * f,struct rtattr * tb[])269 static void gre_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
270 {
271 	char s1[1024];
272 	char s2[64];
273 	const char *local = "any";
274 	const char *remote = "any";
275 	unsigned iflags = 0;
276 	unsigned oflags = 0;
277 
278 	if (!tb)
279 		return;
280 
281 	if (tb[IFLA_GRE_REMOTE]) {
282 		unsigned addr = *(__u32 *)RTA_DATA(tb[IFLA_GRE_REMOTE]);
283 
284 		if (addr)
285 			remote = format_host(AF_INET, 4, &addr, s1, sizeof(s1));
286 	}
287 
288 	fprintf(f, "remote %s ", remote);
289 
290 	if (tb[IFLA_GRE_LOCAL]) {
291 		unsigned addr = *(__u32 *)RTA_DATA(tb[IFLA_GRE_LOCAL]);
292 
293 		if (addr)
294 			local = format_host(AF_INET, 4, &addr, s1, sizeof(s1));
295 	}
296 
297 	fprintf(f, "local %s ", local);
298 
299 	if (tb[IFLA_GRE_LINK] && *(__u32 *)RTA_DATA(tb[IFLA_GRE_LINK])) {
300 		unsigned link = *(__u32 *)RTA_DATA(tb[IFLA_GRE_LINK]);
301 		char *n = tnl_ioctl_get_ifname(link);
302 
303 		if (n)
304 			fprintf(f, "dev %s ", n);
305 		else
306 			fprintf(f, "dev %u ", link);
307 	}
308 
309 	if (tb[IFLA_GRE_TTL] && *(__u8 *)RTA_DATA(tb[IFLA_GRE_TTL]))
310 		fprintf(f, "ttl %d ", *(__u8 *)RTA_DATA(tb[IFLA_GRE_TTL]));
311 	else
312 		fprintf(f, "ttl inherit ");
313 
314 	if (tb[IFLA_GRE_TOS] && *(__u8 *)RTA_DATA(tb[IFLA_GRE_TOS])) {
315 		int tos = *(__u8 *)RTA_DATA(tb[IFLA_GRE_TOS]);
316 
317 		fputs("tos ", f);
318 		if (tos == 1)
319 			fputs("inherit ", f);
320 		else
321 			fprintf(f, "0x%x ", tos);
322 	}
323 
324 	if (tb[IFLA_GRE_PMTUDISC] &&
325 	    !*(__u8 *)RTA_DATA(tb[IFLA_GRE_PMTUDISC]))
326 		fputs("nopmtudisc ", f);
327 
328 	if (tb[IFLA_GRE_IFLAGS])
329 		iflags = *(__u16 *)RTA_DATA(tb[IFLA_GRE_IFLAGS]);
330 
331 	if (tb[IFLA_GRE_OFLAGS])
332 		oflags = *(__u16 *)RTA_DATA(tb[IFLA_GRE_OFLAGS]);
333 
334 	if (iflags & GRE_KEY && tb[IFLA_GRE_IKEY] &&
335 	    *(__u32 *)RTA_DATA(tb[IFLA_GRE_IKEY])) {
336 		inet_ntop(AF_INET, RTA_DATA(tb[IFLA_GRE_IKEY]), s2, sizeof(s2));
337 		fprintf(f, "ikey %s ", s2);
338 	}
339 
340 	if (oflags & GRE_KEY && tb[IFLA_GRE_OKEY] &&
341 	    *(__u32 *)RTA_DATA(tb[IFLA_GRE_OKEY])) {
342 		inet_ntop(AF_INET, RTA_DATA(tb[IFLA_GRE_OKEY]), s2, sizeof(s2));
343 		fprintf(f, "ikey %s ", s2);
344 	}
345 
346 	if (iflags & GRE_SEQ)
347 		fputs("iseq ", f);
348 	if (oflags & GRE_SEQ)
349 		fputs("oseq ", f);
350 	if (iflags & GRE_CSUM)
351 		fputs("icsum ", f);
352 	if (oflags & GRE_CSUM)
353 		fputs("ocsum ", f);
354 }
355 
356 struct link_util gre_link_util = {
357 	.id = "gre",
358 	.maxattr = IFLA_GRE_MAX,
359 	.parse_opt = gre_parse_opt,
360 	.print_opt = gre_print_opt,
361 };
362 
363 struct link_util gretap_link_util = {
364 	.id = "gretap",
365 	.maxattr = IFLA_GRE_MAX,
366 	.parse_opt = gre_parse_opt,
367 	.print_opt = gre_print_opt,
368 };
369