xref: /freebsd/usr.sbin/ndp/ndp_netlink.c (revision 4f8f43b06ed07e96a250855488cc531799d5b78f)
1 #include <sys/param.h>
2 #include <sys/module.h>
3 #include <sys/file.h>
4 #include <sys/ioctl.h>
5 #include <sys/linker.h>
6 #include <sys/socket.h>
7 #include <sys/sysctl.h>
8 #include <sys/time.h>
9 #include <sys/queue.h>
10 
11 #include <net/if.h>
12 #include <net/if_dl.h>
13 #include <net/if_types.h>
14 
15 #include <netinet/in.h>
16 #include <netinet/if_ether.h>
17 
18 #include <netinet/icmp6.h>
19 #include <netinet6/in6_var.h>
20 #include <netinet6/nd6.h>
21 
22 #include <arpa/inet.h>
23 
24 #include <ctype.h>
25 #include <netdb.h>
26 #include <errno.h>
27 #include <nlist.h>
28 #include <stdio.h>
29 #include <string.h>
30 #include <paths.h>
31 #include <err.h>
32 #include <stdlib.h>
33 #include <fcntl.h>
34 #include <unistd.h>
35 #include <libxo/xo.h>
36 
37 
38 #include <netlink/netlink.h>
39 #include <netlink/netlink_route.h>
40 #include <netlink/netlink_snl.h>
41 #include <netlink/netlink_snl_route.h>
42 #include <netlink/netlink_snl_route_compat.h>
43 #include <netlink/netlink_snl_route_parsers.h>
44 
45 #include <libxo/xo.h>
46 #include "ndp.h"
47 
48 #define RTF_ANNOUNCE	RTF_PROTO2
49 
50 static void
51 nl_init_socket(struct snl_state *ss)
52 {
53 	if (snl_init(ss, NETLINK_ROUTE))
54 		return;
55 
56 	if (modfind("netlink") == -1 && errno == ENOENT) {
57 		/* Try to load */
58 		if (kldload("netlink") == -1)
59 			err(1, "netlink is not loaded and load attempt failed");
60 		if (snl_init(ss, NETLINK_ROUTE))
61 			return;
62 	}
63 
64 	err(1, "unable to open netlink socket");
65 }
66 
67 static bool
68 get_link_info(struct snl_state *ss, uint32_t ifindex,
69     struct snl_parsed_link_simple *link)
70 {
71 	struct snl_writer nw;
72 
73 	snl_init_writer(ss, &nw);
74 
75 	struct nlmsghdr *hdr = snl_create_msg_request(&nw, RTM_GETLINK);
76 	struct ifinfomsg *ifmsg = snl_reserve_msg_object(&nw, struct ifinfomsg);
77 	if (ifmsg != NULL)
78 		ifmsg->ifi_index = ifindex;
79 	if (! (hdr = snl_finalize_msg(&nw)) || !snl_send_message(ss, hdr))
80 		return (false);
81 
82 	hdr = snl_read_reply(ss, hdr->nlmsg_seq);
83 
84 	if (hdr == NULL || hdr->nlmsg_type != RTM_NEWLINK)
85 		return (false);
86 
87 	if (!snl_parse_nlmsg(ss, hdr, &snl_rtm_link_parser_simple, link))
88 		return (false);
89 
90 	return (true);
91 }
92 
93 
94 
95 static bool
96 has_l2(struct snl_state *ss, uint32_t ifindex)
97 {
98 	struct snl_parsed_link_simple link = {};
99 
100 	if (!get_link_info(ss, ifindex, &link))
101 		return (false);
102 
103 	return (valid_type(link.ifi_type) != 0);
104 }
105 
106 static uint32_t
107 get_myfib(void)
108 {
109 	uint32_t fibnum = 0;
110 	size_t len = sizeof(fibnum);
111 
112 	sysctlbyname("net.my_fibnum", (void *)&fibnum, &len, NULL, 0);
113 
114 	return (fibnum);
115 }
116 
117 static void
118 ip6_writemask(struct in6_addr *addr6, uint8_t mask)
119 {
120 	uint32_t *cp;
121 
122 	for (cp = (uint32_t *)addr6; mask >= 32; mask -= 32)
123 		*cp++ = 0xFFFFFFFF;
124 	if (mask > 0)
125 		*cp = htonl(mask ? ~((1 << (32 - mask)) - 1) : 0);
126 }
127 #define s6_addr32 __u6_addr.__u6_addr32
128 #define IN6_MASK_ADDR(a, m)	do { \
129 	(a)->s6_addr32[0] &= (m)->s6_addr32[0]; \
130 	(a)->s6_addr32[1] &= (m)->s6_addr32[1]; \
131 	(a)->s6_addr32[2] &= (m)->s6_addr32[2]; \
132 	(a)->s6_addr32[3] &= (m)->s6_addr32[3]; \
133 } while (0)
134 
135 static int
136 guess_ifindex(struct snl_state *ss, uint32_t fibnum, const struct sockaddr_in6 *dst)
137 {
138 	struct snl_writer nw;
139 
140 	if (IN6_IS_ADDR_LINKLOCAL(&dst->sin6_addr))
141 		return (dst->sin6_scope_id);
142 	else if (IN6_IS_ADDR_MULTICAST(&dst->sin6_addr))
143 		return (0);
144 
145 
146 	snl_init_writer(ss, &nw);
147 
148 	struct nlmsghdr *hdr = snl_create_msg_request(&nw, RTM_GETROUTE);
149 	struct rtmsg *rtm = snl_reserve_msg_object(&nw, struct rtmsg);
150 	rtm->rtm_family = AF_INET6;
151 
152 	snl_add_msg_attr_ip(&nw, RTA_DST, (struct sockaddr *)dst);
153 	snl_add_msg_attr_u32(&nw, RTA_TABLE, fibnum);
154 
155 	if (! (hdr = snl_finalize_msg(&nw)) || !snl_send_message(ss, hdr))
156 		return (0);
157 
158 	hdr = snl_read_reply(ss, hdr->nlmsg_seq);
159 
160 	if (hdr->nlmsg_type != NL_RTM_NEWROUTE) {
161 		/* No route found, unable to guess ifindex */
162 		return (0);
163 	}
164 
165 	struct snl_parsed_route r = {};
166 	if (!snl_parse_nlmsg(ss, hdr, &snl_rtm_route_parser, &r))
167 		return (0);
168 
169 	if (r.rta_multipath.num_nhops > 0 || (r.rta_rtflags & RTF_GATEWAY))
170 		return (0);
171 
172 	/* Check if the interface is of supported type */
173 	if (has_l2(ss, r.rta_oif))
174 		return (r.rta_oif);
175 
176 	/* Check the case when we matched the loopback route for P2P */
177 	snl_init_writer(ss, &nw);
178 	hdr = snl_create_msg_request(&nw, RTM_GETNEXTHOP);
179 	snl_reserve_msg_object(&nw, struct nhmsg);
180 
181 	int off = snl_add_msg_attr_nested(&nw, NHA_FREEBSD);
182 	snl_add_msg_attr_u32(&nw, NHAF_KID, r.rta_knh_id);
183 	snl_add_msg_attr_u8(&nw, NHAF_FAMILY, AF_INET);
184 	snl_add_msg_attr_u32(&nw, NHAF_TABLE, fibnum);
185 	snl_end_attr_nested(&nw, off);
186 
187 	if (! (hdr = snl_finalize_msg(&nw)) || !snl_send_message(ss, hdr))
188 		return (0);
189 
190 	hdr = snl_read_reply(ss, hdr->nlmsg_seq);
191 
192 	if (hdr->nlmsg_type != NL_RTM_NEWNEXTHOP) {
193 		/* No nexthop found, unable to guess ifindex */
194 		return (0);
195 	}
196 
197 	struct snl_parsed_nhop nh = {};
198 	if (!snl_parse_nlmsg(ss, hdr, &snl_nhmsg_parser, &nh))
199 		return (0);
200 
201 	return (nh.nhaf_aif);
202 }
203 
204 static uint32_t
205 fix_ifindex(struct snl_state *ss, uint32_t ifindex, const struct sockaddr_in6 *sa)
206 {
207 	if (ifindex == 0)
208 		ifindex = guess_ifindex(ss, get_myfib(), sa);
209 	return (ifindex);
210 }
211 
212 static void
213 print_entry(struct snl_parsed_neigh *neigh, struct snl_parsed_link_simple *link)
214 {
215 	struct timeval now;
216 	char host_buf[NI_MAXHOST];
217 	int addrwidth;
218 	int llwidth;
219 	int ifwidth;
220 	char *ifname;
221 
222 	getnameinfo(neigh->nda_dst, sizeof(struct sockaddr_in6), host_buf,
223 	    sizeof(host_buf), NULL, 0, (opts.nflag ? NI_NUMERICHOST : 0));
224 
225 	gettimeofday(&now, 0);
226 	if (opts.tflag)
227 		ts_print(&now);
228 
229 	struct sockaddr_dl sdl = {
230 		.sdl_family = AF_LINK,
231 		.sdl_type = link->ifi_type,
232 		.sdl_len = sizeof(struct sockaddr_dl),
233 	};
234 
235 	if (neigh->nda_lladdr) {
236 		sdl.sdl_alen = NLA_DATA_LEN(neigh->nda_lladdr),
237 		memcpy(sdl.sdl_data, NLA_DATA(neigh->nda_lladdr), sdl.sdl_alen);
238 	}
239 
240 	addrwidth = strlen(host_buf);
241 	if (addrwidth < W_ADDR)
242 		addrwidth = W_ADDR;
243 	llwidth = strlen(ether_str(&sdl));
244 	if (W_ADDR + W_LL - addrwidth > llwidth)
245 		llwidth = W_ADDR + W_LL - addrwidth;
246 	ifname = link->ifla_ifname;
247 	ifwidth = strlen(ifname);
248 	if (W_ADDR + W_LL + W_IF - addrwidth - llwidth > ifwidth)
249 		ifwidth = W_ADDR + W_LL + W_IF - addrwidth - llwidth;
250 
251 	xo_open_instance("neighbor-cache");
252 	/* Compose format string for libxo, as it doesn't support *.* */
253 	char xobuf[200];
254 	snprintf(xobuf, sizeof(xobuf),
255 	    "{:address/%%-%d.%ds/%%s} {:mac-address/%%-%d.%ds/%%s} {:interface/%%%d.%ds/%%s}",
256 	    addrwidth, addrwidth, llwidth, llwidth, ifwidth, ifwidth);
257 	xo_emit(xobuf, host_buf, ether_str(&sdl), ifname);
258 
259 	/* Print neighbor discovery specific information */
260 	time_t expire = (time_t)neigh->ndaf_next_ts;
261 	int expire_in = expire - now.tv_sec;
262 	if (expire > now.tv_sec)
263 		xo_emit("{d:/ %-9.9s}{e:expires_sec/%d}", sec2str(expire_in), expire_in);
264 	else if (expire == 0)
265 		xo_emit("{d:/ %-9.9s}{en:permanent/true}", "permanent");
266 	else
267 		xo_emit("{d:/ %-9.9s}{e:expires_sec/%d}", "expired", expire_in);
268 
269 	const char *lle_state = "";
270 	switch (neigh->ndm_state) {
271 	case NUD_INCOMPLETE:
272 		lle_state = "I";
273 		break;
274 	case NUD_REACHABLE:
275 		lle_state = "R";
276 		break;
277 	case NUD_STALE:
278 		lle_state = "S";
279 		break;
280 	case NUD_DELAY:
281 		lle_state = "D";
282 		break;
283 	case NUD_PROBE:
284 		lle_state = "P";
285 		break;
286 	case NUD_FAILED:
287 		lle_state = "F";
288 		break;
289 	default:
290 		lle_state = "N";
291 		break;
292 	}
293 	xo_emit(" {:neighbor-state/%s}", lle_state);
294 
295 	bool isrouter = neigh->ndm_flags & NTF_ROUTER;
296 
297 	/*
298 	 * other flags. R: router, P: proxy, W: ??
299 	 */
300 	char flgbuf[8];
301 	snprintf(flgbuf, sizeof(flgbuf), "%s%s",
302 	    isrouter ? "R" : "",
303 	    (neigh->ndm_flags & NTF_PROXY) ? "p" : "");
304 	xo_emit(" {:nd-flags/%s}", flgbuf);
305 
306 	if (neigh->nda_probes != 0)
307 		xo_emit("{u:/ %d}", neigh->nda_probes);
308 
309 	xo_emit("\n");
310 	xo_close_instance("neighbor-cache");
311 }
312 
313 int
314 print_entries_nl(uint32_t ifindex, struct sockaddr_in6 *addr, bool cflag)
315 {
316 	struct snl_state ss_req = {}, ss_cmd = {};
317 	struct snl_parsed_link_simple link = {};
318 	struct snl_writer nw;
319 
320 	nl_init_socket(&ss_req);
321 	snl_init_writer(&ss_req, &nw);
322 
323 	struct nlmsghdr *hdr = snl_create_msg_request(&nw, RTM_GETNEIGH);
324 	struct ndmsg *ndmsg = snl_reserve_msg_object(&nw, struct ndmsg);
325 	if (ndmsg != NULL) {
326 		ndmsg->ndm_family = AF_INET6;
327 		ndmsg->ndm_ifindex = ifindex;
328 	}
329 
330 	if (! (hdr = snl_finalize_msg(&nw)) || !snl_send_message(&ss_req, hdr)) {
331 		snl_free(&ss_req);
332 		return (0);
333 	}
334 
335 	uint32_t nlmsg_seq = hdr->nlmsg_seq;
336 	struct snl_errmsg_data e = {};
337 	int count = 0;
338 	nl_init_socket(&ss_cmd);
339 
340 	/* Print header */
341 	if (!opts.tflag && !cflag) {
342 		char xobuf[200];
343 		snprintf(xobuf, sizeof(xobuf),
344 		    "{T:/%%-%d.%ds} {T:/%%-%d.%ds} {T:/%%%d.%ds} {T:/%%-9.9s} {T:%%1s} {T:%%5s}\n",
345 		    W_ADDR, W_ADDR, W_LL, W_LL, W_IF, W_IF);
346 		xo_emit(xobuf, "Neighbor", "Linklayer Address", "Netif", "Expire", "S", "Flags");
347 	}
348 	xo_open_list("neighbor-cache");
349 
350 	while ((hdr = snl_read_reply_multi(&ss_req, nlmsg_seq, &e)) != NULL) {
351 		struct snl_parsed_neigh neigh = {};
352 
353 		if (!snl_parse_nlmsg(&ss_req, hdr, &snl_rtm_neigh_parser, &neigh))
354 			continue;
355 
356 		if (neigh.nda_ifindex != link.ifi_index) {
357 			snl_clear_lb(&ss_cmd);
358 			memset(&link, 0, sizeof(link));
359 			if (!get_link_info(&ss_cmd, neigh.nda_ifindex, &link))
360 				continue;
361 		}
362 
363 		/* TODO: embed LL in the parser */
364 		struct sockaddr_in6 *dst = (struct sockaddr_in6 *)neigh.nda_dst;
365 		if (IN6_IS_ADDR_LINKLOCAL(&dst->sin6_addr))
366 			dst->sin6_scope_id = neigh.nda_ifindex;
367 
368 		if (addr != NULL) {
369 			if (IN6_ARE_ADDR_EQUAL(&addr->sin6_addr,
370 			    &dst->sin6_addr) == 0 ||
371 			    addr->sin6_scope_id != dst->sin6_scope_id)
372 				continue;
373 		}
374 
375 		print_entry(&neigh, &link);
376 		if (cflag) {
377 			char dst_str[INET6_ADDRSTRLEN];
378 
379 			inet_ntop(AF_INET6, &dst->sin6_addr, dst_str, sizeof(dst_str));
380 			delete_nl(neigh.nda_ifindex, dst_str);
381 		}
382 		count++;
383 		snl_clear_lb(&ss_req);
384 	}
385 	xo_close_list("neighbor-cache");
386 
387 	snl_free(&ss_req);
388 	snl_free(&ss_cmd);
389 
390 	return (count);
391 }
392 
393 int
394 delete_nl(uint32_t ifindex, char *host)
395 {
396 	struct snl_state ss = {};
397 	struct snl_writer nw;
398 	struct sockaddr_in6 dst;
399 
400 	int gai_error = getaddr(host, &dst);
401 	if (gai_error) {
402 		xo_warnx("%s: %s", host, gai_strerror(gai_error));
403 		return 1;
404 	}
405 
406 	nl_init_socket(&ss);
407 
408 	ifindex = fix_ifindex(&ss, ifindex, &dst);
409 	if (ifindex == 0) {
410 		xo_warnx("delete: cannot locate %s", host);
411 		snl_free(&ss);
412 		return (0);
413 	}
414 
415 	snl_init_writer(&ss, &nw);
416 	struct nlmsghdr *hdr = snl_create_msg_request(&nw, RTM_DELNEIGH);
417 	struct ndmsg *ndmsg = snl_reserve_msg_object(&nw, struct ndmsg);
418 	if (ndmsg != NULL) {
419 		ndmsg->ndm_family = AF_INET6;
420 		ndmsg->ndm_ifindex = ifindex;
421 	}
422 	snl_add_msg_attr_ip(&nw, NDA_DST, (struct sockaddr *)&dst);
423 
424 	if (! (hdr = snl_finalize_msg(&nw)) || !snl_send_message(&ss, hdr)) {
425 		snl_free(&ss);
426 		return (1);
427 	}
428 
429 	struct snl_errmsg_data e = {};
430 	snl_read_reply_code(&ss, hdr->nlmsg_seq, &e);
431 	if (e.error != 0) {
432 		if (e.error_str != NULL)
433 			xo_warnx("delete %s: %s (%s)", host, strerror(e.error), e.error_str);
434 		else
435 			xo_warnx("delete %s: %s", host, strerror(e.error));
436 	} else {
437 		char host_buf[NI_MAXHOST];
438 		char ifix_buf[IFNAMSIZ];
439 
440 		getnameinfo((struct sockaddr *)&dst,
441 		    dst.sin6_len, host_buf,
442 		    sizeof(host_buf), NULL, 0,
443 		    (opts.nflag ? NI_NUMERICHOST : 0));
444 
445 		char *ifname = if_indextoname(ifindex, ifix_buf);
446 		if (ifname == NULL) {
447 			strlcpy(ifix_buf, "?", sizeof(ifix_buf));
448 			ifname = ifix_buf;
449 		}
450 		char abuf[INET6_ADDRSTRLEN];
451 		inet_ntop(AF_INET6, &dst.sin6_addr, abuf, sizeof(abuf));
452 
453 		xo_open_instance("neighbor-cache");
454 		xo_emit("{:hostname/%s}{d:/ (%s) deleted\n}", host, host_buf);
455 		xo_emit("{e:address/%s}{e:interface/%s}", abuf, ifname);
456 		xo_close_instance("neighbor-cache");
457 	}
458 	snl_free(&ss);
459 
460 	return (e.error != 0);
461 }
462 
463 int
464 set_nl(uint32_t ifindex, struct sockaddr_in6 *dst, struct sockaddr_dl *sdl, char *host)
465 {
466 	struct snl_state ss = {};
467 	struct snl_writer nw;
468 
469 	nl_init_socket(&ss);
470 
471 	ifindex = fix_ifindex(&ss, ifindex, dst);
472 	if (ifindex == 0) {
473 		xo_warnx("delete: cannot locate %s", host);
474 		snl_free(&ss);
475 		return (0);
476 	}
477 
478 	snl_init_writer(&ss, &nw);
479 	struct nlmsghdr *hdr = snl_create_msg_request(&nw, RTM_NEWNEIGH);
480 	hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
481 	struct ndmsg *ndmsg = snl_reserve_msg_object(&nw, struct ndmsg);
482 	if (ndmsg != NULL) {
483 		uint8_t nl_flags = NTF_STICKY;
484 
485 		ndmsg->ndm_family = AF_INET6;
486 		ndmsg->ndm_ifindex = ifindex;
487 		ndmsg->ndm_state = NUD_PERMANENT;
488 
489 		if (opts.flags & RTF_ANNOUNCE)
490 			nl_flags |= NTF_PROXY;
491 		ndmsg->ndm_flags = nl_flags;
492 	}
493 	snl_add_msg_attr_ip(&nw, NDA_DST, (struct sockaddr *)dst);
494 	snl_add_msg_attr(&nw, NDA_LLADDR, sdl->sdl_alen, LLADDR(sdl));
495 
496 	if (! (hdr = snl_finalize_msg(&nw)) || !snl_send_message(&ss, hdr)) {
497 		snl_free(&ss);
498 		return (1);
499 	}
500 
501 	struct snl_errmsg_data e = {};
502 	snl_read_reply_code(&ss, hdr->nlmsg_seq, &e);
503 	if (e.error != 0) {
504 		if (e.error_str != NULL)
505 			xo_warnx("set: %s: %s (%s)", host, strerror(e.error), e.error_str);
506 		else
507 			xo_warnx("set %s: %s", host, strerror(e.error));
508 	}
509 	snl_free(&ss);
510 
511 	return (e.error != 0);
512 }
513 
514