iprule.c revision aba5acdfdb347d2c21fc67d613d83d4430ca3937 
1/*
2 * iprule.c		"ip rule".
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:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 *
11 *
12 * Changes:
13 *
14 * Rani Assaf <rani@magic.metawire.com> 980929:	resolve addresses
15 */
16
17#include <stdio.h>
18#include <stdlib.h>
19#include <unistd.h>
20#include <syslog.h>
21#include <fcntl.h>
22#include <sys/socket.h>
23#include <netinet/in.h>
24#include <netinet/ip.h>
25#include <arpa/inet.h>
26#include <string.h>
27
28#include "rt_names.h"
29#include "utils.h"
30
31static void usage(void) __attribute__((noreturn));
32
33static void usage(void)
34{
35	fprintf(stderr, "Usage: ip rule [ list | add | del ] SELECTOR ACTION\n");
36	fprintf(stderr, "SELECTOR := [ from PREFIX ] [ to PREFIX ] [ tos TOS ] [ fwmark FWMARK ]\n");
37	fprintf(stderr, "            [ dev STRING ] [ pref NUMBER ]\n");
38	fprintf(stderr, "ACTION := [ table TABLE_ID ] [ nat ADDRESS ]\n");
39	fprintf(stderr, "          [ prohibit | reject | unreachable ]\n");
40	fprintf(stderr, "          [ realms [SRCREALM/]DSTREALM ]\n");
41	fprintf(stderr, "TABLE_ID := [ local | main | default | NUMBER ]\n");
42	exit(-1);
43}
44
45int print_rule(struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
46{
47	FILE *fp = (FILE*)arg;
48	struct rtmsg *r = NLMSG_DATA(n);
49	int len = n->nlmsg_len;
50	int host_len = -1;
51	struct rtattr * tb[RTA_MAX+1];
52	char abuf[256];
53	SPRINT_BUF(b1);
54
55	if (n->nlmsg_type != RTM_NEWRULE)
56		return 0;
57
58	len -= NLMSG_LENGTH(sizeof(*r));
59	if (len < 0)
60		return -1;
61
62	memset(tb, 0, sizeof(tb));
63	parse_rtattr(tb, RTA_MAX, RTM_RTA(r), len);
64
65	if (r->rtm_family == AF_INET)
66		host_len = 32;
67	else if (r->rtm_family == AF_INET6)
68		host_len = 128;
69	else if (r->rtm_family == AF_DECnet)
70		host_len = 16;
71	else if (r->rtm_family == AF_IPX)
72		host_len = 80;
73
74	if (tb[RTA_PRIORITY])
75		fprintf(fp, "%u:\t", *(unsigned*)RTA_DATA(tb[RTA_PRIORITY]));
76	else
77		fprintf(fp, "0:\t");
78
79	if (tb[RTA_SRC]) {
80		if (r->rtm_src_len != host_len) {
81			fprintf(fp, "from %s/%u ", rt_addr_n2a(r->rtm_family,
82							 RTA_PAYLOAD(tb[RTA_SRC]),
83							 RTA_DATA(tb[RTA_SRC]),
84							 abuf, sizeof(abuf)),
85				r->rtm_src_len
86				);
87		} else {
88			fprintf(fp, "from %s ", format_host(r->rtm_family,
89						       RTA_PAYLOAD(tb[RTA_SRC]),
90						       RTA_DATA(tb[RTA_SRC]),
91						       abuf, sizeof(abuf))
92				);
93		}
94	} else if (r->rtm_src_len) {
95		fprintf(fp, "from 0/%d ", r->rtm_src_len);
96	} else {
97		fprintf(fp, "from all ");
98	}
99
100	if (tb[RTA_DST]) {
101		if (r->rtm_dst_len != host_len) {
102			fprintf(fp, "to %s/%u ", rt_addr_n2a(r->rtm_family,
103							 RTA_PAYLOAD(tb[RTA_DST]),
104							 RTA_DATA(tb[RTA_DST]),
105							 abuf, sizeof(abuf)),
106				r->rtm_dst_len
107				);
108		} else {
109			fprintf(fp, "to %s ", format_host(r->rtm_family,
110						       RTA_PAYLOAD(tb[RTA_DST]),
111						       RTA_DATA(tb[RTA_DST]),
112						       abuf, sizeof(abuf)));
113		}
114	} else if (r->rtm_dst_len) {
115		fprintf(fp, "to 0/%d ", r->rtm_dst_len);
116	}
117
118	if (r->rtm_tos) {
119		SPRINT_BUF(b1);
120		fprintf(fp, "tos %s ", rtnl_dsfield_n2a(r->rtm_tos, b1, sizeof(b1)));
121	}
122	if (tb[RTA_PROTOINFO]) {
123		fprintf(fp, "fwmark %8x ", *(__u32*)RTA_DATA(tb[RTA_PROTOINFO]));
124	}
125
126	if (tb[RTA_IIF]) {
127		fprintf(fp, "iif %s ", (char*)RTA_DATA(tb[RTA_IIF]));
128	}
129
130	if (r->rtm_table)
131		fprintf(fp, "lookup %s ", rtnl_rttable_n2a(r->rtm_table, b1, sizeof(b1)));
132
133	if (tb[RTA_FLOW]) {
134		__u32 to = *(__u32*)RTA_DATA(tb[RTA_FLOW]);
135		__u32 from = to>>16;
136		to &= 0xFFFF;
137		if (from) {
138			fprintf(fp, "realms %s/",
139				rtnl_rtrealm_n2a(from, b1, sizeof(b1)));
140		}
141		fprintf(fp, "%s ",
142			rtnl_rtrealm_n2a(to, b1, sizeof(b1)));
143	}
144
145	if (r->rtm_type == RTN_NAT) {
146		if (tb[RTA_GATEWAY]) {
147			fprintf(fp, "map-to %s ",
148				format_host(r->rtm_family,
149					    RTA_PAYLOAD(tb[RTA_GATEWAY]),
150					    RTA_DATA(tb[RTA_GATEWAY]),
151					    abuf, sizeof(abuf)));
152		} else
153			fprintf(fp, "masquerade");
154	} else if (r->rtm_type != RTN_UNICAST)
155		fprintf(fp, "%s", rtnl_rtntype_n2a(r->rtm_type, b1, sizeof(b1)));
156
157	fprintf(fp, "\n");
158	fflush(fp);
159	return 0;
160}
161
162int iprule_list(int argc, char **argv)
163{
164	struct rtnl_handle rth;
165	int af = preferred_family;
166
167	if (af == AF_UNSPEC)
168		af = AF_INET;
169
170	if (argc > 0) {
171		fprintf(stderr, "\"ip rule show\" need not eny arguments.\n");
172		return -1;
173	}
174
175	if (rtnl_open(&rth, 0) < 0)
176		return 1;
177
178	if (rtnl_wilddump_request(&rth, af, RTM_GETRULE) < 0) {
179		perror("Cannot send dump request");
180		return 1;
181	}
182
183	if (rtnl_dump_filter(&rth, print_rule, stdout, NULL, NULL) < 0) {
184		fprintf(stderr, "Dump terminated\n");
185		return 1;
186	}
187
188	return 0;
189}
190
191
192int iprule_modify(int cmd, int argc, char **argv)
193{
194	int table_ok = 0;
195	struct rtnl_handle rth;
196	struct {
197		struct nlmsghdr 	n;
198		struct rtmsg 		r;
199		char   			buf[1024];
200	} req;
201
202	memset(&req, 0, sizeof(req));
203
204	req.n.nlmsg_type = cmd;
205	req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
206	req.n.nlmsg_flags = NLM_F_REQUEST;
207	req.r.rtm_family = preferred_family;
208	req.r.rtm_protocol = RTPROT_BOOT;
209	req.r.rtm_scope = RT_SCOPE_UNIVERSE;
210	req.r.rtm_table = 0;
211	req.r.rtm_type = RTN_UNSPEC;
212
213	if (cmd == RTM_NEWRULE) {
214		req.n.nlmsg_flags |= NLM_F_CREATE|NLM_F_EXCL;
215		req.r.rtm_type = RTN_UNICAST;
216	}
217
218	while (argc > 0) {
219		if (strcmp(*argv, "from") == 0) {
220			inet_prefix dst;
221			NEXT_ARG();
222			get_prefix(&dst, *argv, req.r.rtm_family);
223			req.r.rtm_src_len = dst.bitlen;
224			addattr_l(&req.n, sizeof(req), RTA_SRC, &dst.data, dst.bytelen);
225		} else if (strcmp(*argv, "to") == 0) {
226			inet_prefix dst;
227			NEXT_ARG();
228			get_prefix(&dst, *argv, req.r.rtm_family);
229			req.r.rtm_dst_len = dst.bitlen;
230			addattr_l(&req.n, sizeof(req), RTA_DST, &dst.data, dst.bytelen);
231		} else if (matches(*argv, "preference") == 0 ||
232			   matches(*argv, "order") == 0 ||
233			   matches(*argv, "priority") == 0) {
234			__u32 pref;
235			NEXT_ARG();
236			if (get_u32(&pref, *argv, 0))
237				invarg("preference value is invalid\n", *argv);
238			addattr32(&req.n, sizeof(req), RTA_PRIORITY, pref);
239		} else if (strcmp(*argv, "tos") == 0) {
240			__u32 tos;
241			NEXT_ARG();
242			if (rtnl_dsfield_a2n(&tos, *argv))
243				invarg("TOS value is invalid\n", *argv);
244			req.r.rtm_tos = tos;
245		} else if (strcmp(*argv, "fwmark") == 0) {
246			__u32 fwmark;
247			NEXT_ARG();
248			if (get_u32(&fwmark, *argv, 16))
249				invarg("fwmark value is invalid\n", *argv);
250			addattr32(&req.n, sizeof(req), RTA_PROTOINFO, fwmark);
251		} else if (matches(*argv, "realms") == 0) {
252			__u32 realm;
253			NEXT_ARG();
254			if (get_rt_realms(&realm, *argv))
255				invarg("invalid realms\n", *argv);
256			addattr32(&req.n, sizeof(req), RTA_FLOW, realm);
257		} else if (matches(*argv, "table") == 0 ||
258			   strcmp(*argv, "lookup") == 0) {
259			int tid;
260			NEXT_ARG();
261			if (rtnl_rttable_a2n(&tid, *argv))
262				invarg("invalid table ID\n", *argv);
263			req.r.rtm_table = tid;
264			table_ok = 1;
265		} else if (strcmp(*argv, "dev") == 0 ||
266			   strcmp(*argv, "iif") == 0) {
267			NEXT_ARG();
268			addattr_l(&req.n, sizeof(req), RTA_IIF, *argv, strlen(*argv)+1);
269		} else if (strcmp(*argv, "nat") == 0 ||
270			   matches(*argv, "map-to") == 0) {
271			NEXT_ARG();
272			addattr32(&req.n, sizeof(req), RTA_GATEWAY, get_addr32(*argv));
273			req.r.rtm_type = RTN_NAT;
274		} else {
275			int type;
276
277			if (strcmp(*argv, "type") == 0) {
278				NEXT_ARG();
279			}
280			if (matches(*argv, "help") == 0)
281				usage();
282			if (rtnl_rtntype_a2n(&type, *argv))
283				invarg("Failed to parse rule type", *argv);
284			req.r.rtm_type = type;
285		}
286		argc--;
287		argv++;
288	}
289
290	if (req.r.rtm_family == AF_UNSPEC)
291		req.r.rtm_family = AF_INET;
292
293	if (!table_ok && cmd == RTM_NEWRULE)
294		req.r.rtm_table = RT_TABLE_MAIN;
295
296	if (rtnl_open(&rth, 0) < 0)
297		return 1;
298
299	if (rtnl_talk(&rth, &req.n, 0, 0, NULL, NULL, NULL) < 0)
300		return 2;
301
302	return 0;
303}
304
305int do_iprule(int argc, char **argv)
306{
307	if (argc < 1) {
308		return iprule_list(0, NULL);
309	} else if (matches(argv[0], "list") == 0 ||
310		   matches(argv[0], "lst") == 0 ||
311		   matches(argv[0], "show") == 0) {
312		return iprule_list(argc-1, argv+1);
313	} else if (matches(argv[0], "add") == 0) {
314		return iprule_modify(RTM_NEWRULE, argc-1, argv+1);
315	} else if (matches(argv[0], "delete") == 0) {
316		return iprule_modify(RTM_DELRULE, argc-1, argv+1);
317	} else if (matches(argv[0], "help") == 0)
318		usage();
319
320	fprintf(stderr, "Command \"%s\" is unknown, try \"ip rule help\".\n", *argv);
321	exit(-1);
322}
323
324