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5adc2528 AS |
1 | /* |
2 | * Code for encoding/decoding FPM messages that are in netlink format. | |
3 | * | |
4 | * Copyright (C) 1997, 98, 99 Kunihiro Ishiguro | |
5 | * Copyright (C) 2012 by Open Source Routing. | |
6 | * Copyright (C) 2012 by Internet Systems Consortium, Inc. ("ISC") | |
7 | * | |
8 | * This file is part of GNU Zebra. | |
9 | * | |
10 | * GNU Zebra is free software; you can redistribute it and/or modify it | |
11 | * under the terms of the GNU General Public License as published by the | |
12 | * Free Software Foundation; either version 2, or (at your option) any | |
13 | * later version. | |
14 | * | |
15 | * GNU Zebra is distributed in the hope that it will be useful, but | |
16 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
18 | * General Public License for more details. | |
19 | * | |
20 | * You should have received a copy of the GNU General Public License | |
21 | * along with GNU Zebra; see the file COPYING. If not, write to the Free | |
22 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA | |
23 | * 02111-1307, USA. | |
24 | */ | |
25 | ||
26 | #include <zebra.h> | |
27 | ||
28 | #include "log.h" | |
29 | #include "rib.h" | |
30 | ||
31 | #include "rt_netlink.h" | |
32 | ||
33 | #include "zebra_fpm_private.h" | |
34 | ||
35 | /* | |
36 | * addr_to_a | |
37 | * | |
38 | * Returns string representation of an address of the given AF. | |
39 | */ | |
40 | static inline const char * | |
41 | addr_to_a (u_char af, void *addr) | |
42 | { | |
43 | if (!addr) | |
44 | return "<No address>"; | |
45 | ||
46 | switch (af) | |
47 | { | |
48 | ||
49 | case AF_INET: | |
50 | return inet_ntoa (*((struct in_addr *) addr)); | |
51 | ||
52 | #ifdef HAVE_IPV6 | |
53 | case AF_INET6: | |
54 | return inet6_ntoa (*((struct in6_addr *) addr)); | |
55 | #endif | |
56 | ||
57 | default: | |
58 | return "<Addr in unknown AF>"; | |
59 | } | |
60 | } | |
61 | ||
62 | /* | |
63 | * prefix_addr_to_a | |
64 | * | |
65 | * Convience wrapper that returns a human-readable string for the | |
66 | * address in a prefix. | |
67 | */ | |
68 | static const char * | |
69 | prefix_addr_to_a (struct prefix *prefix) | |
70 | { | |
71 | if (!prefix) | |
72 | return "<No address>"; | |
73 | ||
74 | return addr_to_a (prefix->family, &prefix->u.prefix); | |
75 | } | |
76 | ||
77 | /* | |
78 | * af_addr_size | |
79 | * | |
80 | * The size of an address in a given address family. | |
81 | */ | |
82 | static size_t | |
83 | af_addr_size (u_char af) | |
84 | { | |
85 | switch (af) | |
86 | { | |
87 | ||
88 | case AF_INET: | |
89 | return 4; | |
90 | ||
91 | #ifdef HAVE_IPV6 | |
92 | case AF_INET6: | |
93 | return 16; | |
94 | #endif | |
95 | ||
96 | default: | |
97 | assert(0); | |
98 | return 16; | |
99 | } | |
100 | } | |
101 | ||
102 | /* | |
103 | * netlink_nh_info_t | |
104 | * | |
105 | * Holds information about a single nexthop for netlink. These info | |
106 | * structures are transient and may contain pointers into rib | |
107 | * data structures for convenience. | |
108 | */ | |
109 | typedef struct netlink_nh_info_t_ | |
110 | { | |
111 | uint32_t if_index; | |
112 | union g_addr *gateway; | |
113 | ||
114 | /* | |
115 | * Information from the struct nexthop from which this nh was | |
116 | * derived. For debug purposes only. | |
117 | */ | |
118 | int recursive; | |
119 | enum nexthop_types_t type; | |
120 | } netlink_nh_info_t; | |
121 | ||
122 | /* | |
123 | * netlink_route_info_t | |
124 | * | |
125 | * A structure for holding information for a netlink route message. | |
126 | */ | |
127 | typedef struct netlink_route_info_t_ | |
128 | { | |
129 | uint16_t nlmsg_type; | |
130 | u_char rtm_type; | |
131 | uint32_t rtm_table; | |
132 | u_char rtm_protocol; | |
133 | u_char af; | |
134 | struct prefix *prefix; | |
135 | uint32_t *metric; | |
136 | int num_nhs; | |
137 | ||
138 | /* | |
139 | * Nexthop structures. We keep things simple for now by enforcing a | |
140 | * maximum of 64 in case MULTIPATH_NUM is 0; | |
141 | */ | |
142 | netlink_nh_info_t nhs[MAX (MULTIPATH_NUM, 64)]; | |
143 | union g_addr *pref_src; | |
144 | } netlink_route_info_t; | |
145 | ||
146 | /* | |
147 | * netlink_route_info_add_nh | |
148 | * | |
149 | * Add information about the given nexthop to the given route info | |
150 | * structure. | |
151 | * | |
152 | * Returns TRUE if a nexthop was added, FALSE otherwise. | |
153 | */ | |
154 | static int | |
fa713d9e CF |
155 | netlink_route_info_add_nh (netlink_route_info_t *ri, struct nexthop *nexthop, |
156 | int recursive) | |
5adc2528 AS |
157 | { |
158 | netlink_nh_info_t nhi; | |
159 | union g_addr *src; | |
160 | ||
161 | memset (&nhi, 0, sizeof (nhi)); | |
162 | src = NULL; | |
163 | ||
164 | if (ri->num_nhs >= (int) ZEBRA_NUM_OF (ri->nhs)) | |
165 | return 0; | |
166 | ||
fa713d9e | 167 | nhi.recursive = recursive; |
5adc2528 | 168 | nhi.type = nexthop->type; |
324ed1f8 | 169 | nhi.if_index = nexthop->ifindex; |
5adc2528 AS |
170 | |
171 | if (nexthop->type == NEXTHOP_TYPE_IPV4 | |
172 | || nexthop->type == NEXTHOP_TYPE_IPV4_IFINDEX) | |
173 | { | |
174 | nhi.gateway = &nexthop->gate; | |
175 | if (nexthop->src.ipv4.s_addr) | |
176 | src = &nexthop->src; | |
177 | } | |
178 | ||
179 | #ifdef HAVE_IPV6 | |
180 | if (nexthop->type == NEXTHOP_TYPE_IPV6 | |
181 | || nexthop->type == NEXTHOP_TYPE_IPV6_IFNAME | |
182 | || nexthop->type == NEXTHOP_TYPE_IPV6_IFINDEX) | |
183 | { | |
184 | nhi.gateway = &nexthop->gate; | |
185 | } | |
186 | #endif /* HAVE_IPV6 */ | |
324ed1f8 | 187 | |
5adc2528 | 188 | if (nexthop->type == NEXTHOP_TYPE_IFINDEX |
324ed1f8 | 189 | || nexthop->type == NEXTHOP_TYPE_IFNAME) |
5adc2528 | 190 | { |
5adc2528 AS |
191 | if (nexthop->src.ipv4.s_addr) |
192 | src = &nexthop->src; | |
193 | } | |
5adc2528 | 194 | |
5adc2528 AS |
195 | if (!nhi.gateway && nhi.if_index == 0) |
196 | return 0; | |
197 | ||
198 | /* | |
199 | * We have a valid nhi. Copy the structure over to the route_info. | |
200 | */ | |
201 | ri->nhs[ri->num_nhs] = nhi; | |
202 | ri->num_nhs++; | |
203 | ||
204 | if (src && !ri->pref_src) | |
205 | ri->pref_src = src; | |
206 | ||
207 | return 1; | |
208 | } | |
209 | ||
210 | /* | |
211 | * netlink_proto_from_route_type | |
212 | */ | |
213 | static u_char | |
214 | netlink_proto_from_route_type (int type) | |
215 | { | |
216 | switch (type) | |
217 | { | |
218 | case ZEBRA_ROUTE_KERNEL: | |
219 | case ZEBRA_ROUTE_CONNECT: | |
220 | return RTPROT_KERNEL; | |
221 | ||
222 | default: | |
223 | return RTPROT_ZEBRA; | |
224 | } | |
225 | } | |
226 | ||
227 | /* | |
228 | * netlink_route_info_fill | |
229 | * | |
230 | * Fill out the route information object from the given route. | |
231 | * | |
232 | * Returns TRUE on success and FALSE on failure. | |
233 | */ | |
234 | static int | |
235 | netlink_route_info_fill (netlink_route_info_t *ri, int cmd, | |
236 | rib_dest_t *dest, struct rib *rib) | |
237 | { | |
fa713d9e CF |
238 | struct nexthop *nexthop, *tnexthop; |
239 | int recursing; | |
5adc2528 AS |
240 | int discard; |
241 | ||
242 | memset (ri, 0, sizeof (*ri)); | |
243 | ||
244 | ri->prefix = rib_dest_prefix (dest); | |
245 | ri->af = rib_dest_af (dest); | |
246 | ||
247 | ri->nlmsg_type = cmd; | |
248 | ri->rtm_table = rib_dest_vrf (dest)->id; | |
249 | ri->rtm_protocol = RTPROT_UNSPEC; | |
250 | ||
251 | /* | |
252 | * An RTM_DELROUTE need not be accompanied by any nexthops, | |
253 | * particularly in our communication with the FPM. | |
254 | */ | |
255 | if (cmd == RTM_DELROUTE && !rib) | |
256 | goto skip; | |
257 | ||
258 | if (rib) | |
259 | ri->rtm_protocol = netlink_proto_from_route_type (rib->type); | |
260 | ||
261 | if ((rib->flags & ZEBRA_FLAG_BLACKHOLE) || (rib->flags & ZEBRA_FLAG_REJECT)) | |
262 | discard = 1; | |
263 | else | |
264 | discard = 0; | |
265 | ||
266 | if (cmd == RTM_NEWROUTE) | |
267 | { | |
268 | if (discard) | |
269 | { | |
270 | if (rib->flags & ZEBRA_FLAG_BLACKHOLE) | |
271 | ri->rtm_type = RTN_BLACKHOLE; | |
272 | else if (rib->flags & ZEBRA_FLAG_REJECT) | |
273 | ri->rtm_type = RTN_UNREACHABLE; | |
274 | else | |
275 | assert (0); | |
276 | } | |
277 | else | |
278 | ri->rtm_type = RTN_UNICAST; | |
279 | } | |
280 | ||
281 | ri->metric = &rib->metric; | |
282 | ||
283 | if (discard) | |
284 | { | |
285 | goto skip; | |
286 | } | |
287 | ||
fa713d9e | 288 | for (ALL_NEXTHOPS_RO(rib->nexthop, nexthop, tnexthop, recursing)) |
5adc2528 | 289 | { |
fa713d9e CF |
290 | if (MULTIPATH_NUM != 0 && ri->num_nhs >= MULTIPATH_NUM) |
291 | break; | |
5adc2528 | 292 | |
fa713d9e CF |
293 | if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_RECURSIVE)) |
294 | continue; | |
295 | ||
296 | if ((cmd == RTM_NEWROUTE | |
297 | && CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE)) | |
298 | || (cmd == RTM_DELROUTE | |
299 | && CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB))) | |
5adc2528 | 300 | { |
fa713d9e | 301 | netlink_route_info_add_nh (ri, nexthop, recursing); |
5adc2528 AS |
302 | } |
303 | } | |
304 | ||
305 | /* If there is no useful nexthop then return. */ | |
306 | if (ri->num_nhs == 0) | |
307 | { | |
308 | zfpm_debug ("netlink_encode_route(): No useful nexthop."); | |
309 | return 0; | |
310 | } | |
311 | ||
312 | skip: | |
313 | return 1; | |
314 | } | |
315 | ||
316 | /* | |
317 | * netlink_route_info_encode | |
318 | * | |
319 | * Returns the number of bytes written to the buffer. 0 or a negative | |
320 | * value indicates an error. | |
321 | */ | |
322 | static int | |
323 | netlink_route_info_encode (netlink_route_info_t *ri, char *in_buf, | |
324 | size_t in_buf_len) | |
325 | { | |
326 | int bytelen; | |
327 | int nexthop_num = 0; | |
328 | size_t buf_offset; | |
329 | netlink_nh_info_t *nhi; | |
330 | ||
331 | struct | |
332 | { | |
333 | struct nlmsghdr n; | |
334 | struct rtmsg r; | |
335 | char buf[1]; | |
336 | } *req; | |
337 | ||
338 | req = (void *) in_buf; | |
339 | ||
340 | buf_offset = ((char *) req->buf) - ((char *) req); | |
341 | ||
342 | if (in_buf_len < buf_offset) { | |
343 | assert(0); | |
344 | return 0; | |
345 | } | |
346 | ||
347 | memset (req, 0, buf_offset); | |
348 | ||
349 | bytelen = af_addr_size (ri->af); | |
350 | ||
351 | req->n.nlmsg_len = NLMSG_LENGTH (sizeof (struct rtmsg)); | |
352 | req->n.nlmsg_flags = NLM_F_CREATE | NLM_F_REQUEST; | |
353 | req->n.nlmsg_type = ri->nlmsg_type; | |
354 | req->r.rtm_family = ri->af; | |
355 | req->r.rtm_table = ri->rtm_table; | |
356 | req->r.rtm_dst_len = ri->prefix->prefixlen; | |
357 | req->r.rtm_protocol = ri->rtm_protocol; | |
358 | req->r.rtm_scope = RT_SCOPE_UNIVERSE; | |
359 | ||
360 | addattr_l (&req->n, in_buf_len, RTA_DST, &ri->prefix->u.prefix, bytelen); | |
361 | ||
362 | req->r.rtm_type = ri->rtm_type; | |
363 | ||
364 | /* Metric. */ | |
365 | if (ri->metric) | |
366 | addattr32 (&req->n, in_buf_len, RTA_PRIORITY, *ri->metric); | |
367 | ||
368 | if (ri->num_nhs == 0) | |
369 | goto done; | |
370 | ||
371 | if (ri->num_nhs == 1) | |
372 | { | |
373 | nhi = &ri->nhs[0]; | |
374 | ||
375 | if (nhi->gateway) | |
376 | { | |
377 | addattr_l (&req->n, in_buf_len, RTA_GATEWAY, nhi->gateway, | |
378 | bytelen); | |
379 | } | |
380 | ||
381 | if (nhi->if_index) | |
382 | { | |
383 | addattr32 (&req->n, in_buf_len, RTA_OIF, nhi->if_index); | |
384 | } | |
385 | ||
386 | goto done; | |
387 | ||
388 | } | |
389 | ||
390 | /* | |
391 | * Multipath case. | |
392 | */ | |
393 | char buf[NL_PKT_BUF_SIZE]; | |
394 | struct rtattr *rta = (void *) buf; | |
395 | struct rtnexthop *rtnh; | |
396 | ||
397 | rta->rta_type = RTA_MULTIPATH; | |
398 | rta->rta_len = RTA_LENGTH (0); | |
399 | rtnh = RTA_DATA (rta); | |
400 | ||
401 | for (nexthop_num = 0; nexthop_num < ri->num_nhs; nexthop_num++) | |
402 | { | |
403 | nhi = &ri->nhs[nexthop_num]; | |
404 | ||
405 | rtnh->rtnh_len = sizeof (*rtnh); | |
406 | rtnh->rtnh_flags = 0; | |
407 | rtnh->rtnh_hops = 0; | |
408 | rtnh->rtnh_ifindex = 0; | |
409 | rta->rta_len += rtnh->rtnh_len; | |
410 | ||
411 | if (nhi->gateway) | |
412 | { | |
413 | rta_addattr_l (rta, sizeof (buf), RTA_GATEWAY, nhi->gateway, bytelen); | |
414 | rtnh->rtnh_len += sizeof (struct rtattr) + bytelen; | |
415 | } | |
416 | ||
417 | if (nhi->if_index) | |
418 | { | |
419 | rtnh->rtnh_ifindex = nhi->if_index; | |
420 | } | |
421 | ||
422 | rtnh = RTNH_NEXT (rtnh); | |
423 | } | |
424 | ||
425 | assert (rta->rta_len > RTA_LENGTH (0)); | |
426 | addattr_l (&req->n, in_buf_len, RTA_MULTIPATH, RTA_DATA (rta), | |
427 | RTA_PAYLOAD (rta)); | |
428 | ||
429 | done: | |
430 | ||
431 | if (ri->pref_src) | |
432 | { | |
433 | addattr_l (&req->n, in_buf_len, RTA_PREFSRC, &ri->pref_src, bytelen); | |
434 | } | |
435 | ||
436 | assert (req->n.nlmsg_len < in_buf_len); | |
437 | return req->n.nlmsg_len; | |
438 | } | |
439 | ||
440 | /* | |
441 | * zfpm_log_route_info | |
442 | * | |
443 | * Helper function to log the information in a route_info structure. | |
444 | */ | |
445 | static void | |
446 | zfpm_log_route_info (netlink_route_info_t *ri, const char *label) | |
447 | { | |
448 | netlink_nh_info_t *nhi; | |
449 | int i; | |
450 | ||
451 | zfpm_debug ("%s : %s %s/%d, Proto: %s, Metric: %u", label, | |
452 | nl_msg_type_to_str (ri->nlmsg_type), | |
453 | prefix_addr_to_a (ri->prefix), ri->prefix->prefixlen, | |
454 | nl_rtproto_to_str (ri->rtm_protocol), | |
455 | ri->metric ? *ri->metric : 0); | |
456 | ||
457 | for (i = 0; i < ri->num_nhs; i++) | |
458 | { | |
459 | nhi = &ri->nhs[i]; | |
460 | zfpm_debug(" Intf: %u, Gateway: %s, Recursive: %s, Type: %s", | |
461 | nhi->if_index, addr_to_a (ri->af, nhi->gateway), | |
462 | nhi->recursive ? "yes" : "no", | |
463 | nexthop_type_to_str (nhi->type)); | |
464 | } | |
465 | } | |
466 | ||
467 | /* | |
468 | * zfpm_netlink_encode_route | |
469 | * | |
470 | * Create a netlink message corresponding to the given route in the | |
471 | * given buffer space. | |
472 | * | |
473 | * Returns the number of bytes written to the buffer. 0 or a negative | |
474 | * value indicates an error. | |
475 | */ | |
476 | int | |
477 | zfpm_netlink_encode_route (int cmd, rib_dest_t *dest, struct rib *rib, | |
478 | char *in_buf, size_t in_buf_len) | |
479 | { | |
480 | netlink_route_info_t ri_space, *ri; | |
481 | ||
482 | ri = &ri_space; | |
483 | ||
484 | if (!netlink_route_info_fill (ri, cmd, dest, rib)) | |
485 | return 0; | |
486 | ||
487 | zfpm_log_route_info (ri, __FUNCTION__); | |
488 | ||
489 | return netlink_route_info_encode (ri, in_buf, in_buf_len); | |
490 | } |