2 * Copyright (c) 2011, 2012, 2013 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
19 #include "route-table.h"
21 #include <arpa/inet.h>
22 #include <sys/socket.h>
23 #include <linux/rtnetlink.h>
29 #include "netlink-notifier.h"
30 #include "netlink-socket.h"
32 #include "rtnetlink-link.h"
35 VLOG_DEFINE_THIS_MODULE(route_table);
38 /* Copied from struct rtmsg. */
39 unsigned char rtm_dst_len;
41 /* Extracted from Netlink attributes. */
42 uint32_t rta_dst; /* Destination in host byte order. 0 if missing. */
43 int rta_oif; /* Output interface index. */
46 /* A digested version of a route message sent down by the kernel to indicate
47 * that a route has changed. */
48 struct route_table_msg {
49 bool relevant; /* Should this message be processed? */
50 int nlmsg_type; /* e.g. RTM_NEWROUTE, RTM_DELROUTE. */
51 struct route_data rd; /* Data parsed from this message. */
55 struct hmap_node node; /* Node in route_map. */
56 struct route_data rd; /* Data associated with this node. */
60 struct hmap_node node; /* Node in name_map. */
61 uint32_t ifi_index; /* Kernel interface index. */
63 char ifname[IFNAMSIZ]; /* Interface name. */
66 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
68 static unsigned int register_count = 0;
69 static struct nln *nln = NULL;
70 static struct route_table_msg rtmsg;
71 static struct nln_notifier *route_notifier = NULL;
72 static struct nln_notifier *name_notifier = NULL;
74 static bool route_table_valid = false;
75 static bool name_table_valid = false;
76 static struct hmap route_map;
77 static struct hmap name_map;
79 static int route_table_reset(void);
80 static void route_table_handle_msg(const struct route_table_msg *);
81 static bool route_table_parse(struct ofpbuf *, struct route_table_msg *);
82 static void route_table_change(const struct route_table_msg *, void *);
83 static struct route_node *route_node_lookup(const struct route_data *);
84 static struct route_node *route_node_lookup_by_ip(uint32_t ip);
85 static void route_map_clear(void);
86 static uint32_t hash_route_data(const struct route_data *);
88 static void name_table_init(void);
89 static void name_table_uninit(void);
90 static int name_table_reset(void);
91 static void name_table_change(const struct rtnetlink_link_change *, void *);
92 static void name_map_clear(void);
93 static struct name_node *name_node_lookup(int ifi_index);
95 /* Populates 'name' with the name of the interface traffic destined for 'ip'
96 * is likely to egress out of (see route_table_get_ifindex).
98 * Returns true if successful, otherwise false. */
100 route_table_get_name(ovs_be32 ip, char name[IFNAMSIZ])
104 if (!name_table_valid) {
108 if (route_table_get_ifindex(ip, &ifindex)) {
109 struct name_node *nn;
111 nn = name_node_lookup(ifindex);
113 ovs_strlcpy(name, nn->ifname, IFNAMSIZ);
121 /* Populates 'ifindex' with the interface index traffic destined for 'ip' is
122 * likely to egress. There is no hard guarantee that traffic destined for 'ip'
123 * will egress out the specified interface. 'ifindex' may refer to an
124 * interface which is not physical (such as a bridge port).
126 * Returns true if successful, otherwise false. */
128 route_table_get_ifindex(ovs_be32 ip_, int *ifindex)
130 struct route_node *rn;
131 uint32_t ip = ntohl(ip_);
135 if (!route_table_valid) {
139 rn = route_node_lookup_by_ip(ip);
142 *ifindex = rn->rd.rta_oif;
146 /* Choose a default route. */
147 HMAP_FOR_EACH(rn, node, &route_map) {
148 if (rn->rd.rta_dst == 0 && rn->rd.rtm_dst_len == 0) {
149 *ifindex = rn->rd.rta_oif;
157 /* Users of the route_table module should register themselves with this
158 * function before making any other route_table function calls. */
160 route_table_register(void)
162 if (!register_count) {
164 ovs_assert(!route_notifier);
166 nln = nln_create(NETLINK_ROUTE, RTNLGRP_IPV4_ROUTE,
167 (nln_parse_func *) route_table_parse, &rtmsg);
170 nln_notifier_create(nln, (nln_notify_func *) route_table_change,
173 hmap_init(&route_map);
181 /* Users of the route_table module should unregister themselves with this
182 * function when they will no longer be making any more route_table fuction
185 route_table_unregister(void)
189 if (!register_count) {
190 nln_notifier_destroy(route_notifier);
191 route_notifier = NULL;
196 hmap_destroy(&route_map);
201 /* Run periodically to update the locally maintained routing table. */
203 route_table_run(void)
206 rtnetlink_link_run();
211 /* Causes poll_block() to wake up when route_table updates are required. */
213 route_table_wait(void)
216 rtnetlink_link_wait();
222 route_table_reset(void)
225 struct rtgenmsg *rtmsg;
226 uint64_t reply_stub[NL_DUMP_BUFSIZE / 8];
227 struct ofpbuf request, reply, buf;
230 route_table_valid = true;
232 ofpbuf_init(&request, 0);
234 nl_msg_put_nlmsghdr(&request, sizeof *rtmsg, RTM_GETROUTE, NLM_F_REQUEST);
236 rtmsg = ofpbuf_put_zeros(&request, sizeof *rtmsg);
237 rtmsg->rtgen_family = AF_INET;
239 nl_dump_start(&dump, NETLINK_ROUTE, &request);
240 ofpbuf_uninit(&request);
242 ofpbuf_use_stub(&buf, reply_stub, sizeof reply_stub);
243 while (nl_dump_next(&dump, &reply, &buf)) {
244 struct route_table_msg msg;
246 if (route_table_parse(&reply, &msg)) {
247 route_table_handle_msg(&msg);
252 return nl_dump_done(&dump);
257 route_table_parse(struct ofpbuf *buf, struct route_table_msg *change)
261 static const struct nl_policy policy[] = {
262 [RTA_DST] = { .type = NL_A_U32, .optional = true },
263 [RTA_OIF] = { .type = NL_A_U32, .optional = false },
266 struct nlattr *attrs[ARRAY_SIZE(policy)];
268 parsed = nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct rtmsg),
269 policy, attrs, ARRAY_SIZE(policy));
272 const struct rtmsg *rtm;
273 const struct nlmsghdr *nlmsg;
276 rtm = ofpbuf_at(buf, NLMSG_HDRLEN, sizeof *rtm);
278 if (rtm->rtm_family != AF_INET) {
279 VLOG_DBG_RL(&rl, "received non AF_INET rtnetlink route message");
283 memset(change, 0, sizeof *change);
284 change->relevant = true;
286 if (rtm->rtm_scope == RT_SCOPE_NOWHERE) {
287 change->relevant = false;
290 if (rtm->rtm_type != RTN_UNICAST &&
291 rtm->rtm_type != RTN_LOCAL) {
292 change->relevant = false;
295 change->nlmsg_type = nlmsg->nlmsg_type;
296 change->rd.rtm_dst_len = rtm->rtm_dst_len;
297 change->rd.rta_oif = nl_attr_get_u32(attrs[RTA_OIF]);
299 if (attrs[RTA_DST]) {
300 change->rd.rta_dst = ntohl(nl_attr_get_be32(attrs[RTA_DST]));
304 VLOG_DBG_RL(&rl, "received unparseable rtnetlink route message");
311 route_table_change(const struct route_table_msg *change OVS_UNUSED,
312 void *aux OVS_UNUSED)
314 route_table_valid = false;
318 route_table_handle_msg(const struct route_table_msg *change)
320 if (change->relevant && change->nlmsg_type == RTM_NEWROUTE &&
321 !route_node_lookup(&change->rd)) {
322 struct route_node *rn;
324 rn = xzalloc(sizeof *rn);
325 memcpy(&rn->rd, &change->rd, sizeof change->rd);
327 hmap_insert(&route_map, &rn->node, hash_route_data(&rn->rd));
331 static struct route_node *
332 route_node_lookup(const struct route_data *rd)
334 struct route_node *rn;
336 HMAP_FOR_EACH_WITH_HASH(rn, node, hash_route_data(rd), &route_map) {
337 if (!memcmp(&rn->rd, rd, sizeof *rd)) {
345 static struct route_node *
346 route_node_lookup_by_ip(uint32_t ip)
349 struct route_node *rn, *rn_ret;
354 HMAP_FOR_EACH(rn, node, &route_map) {
355 uint32_t mask = 0xffffffff << (32 - rn->rd.rtm_dst_len);
357 if (rn->rd.rta_dst == 0 && rn->rd.rtm_dst_len == 0) {
362 if (rn->rd.rtm_dst_len > dst_len &&
363 (ip & mask) == (rn->rd.rta_dst & mask)) {
365 dst_len = rn->rd.rtm_dst_len;
373 route_map_clear(void)
375 struct route_node *rn, *rn_next;
377 HMAP_FOR_EACH_SAFE(rn, rn_next, node, &route_map) {
378 hmap_remove(&route_map, &rn->node);
384 hash_route_data(const struct route_data *rd)
386 return hash_bytes(rd, sizeof *rd, 0);
392 name_table_init(void)
394 hmap_init(&name_map);
395 name_notifier = rtnetlink_link_notifier_create(name_table_change, NULL);
396 name_table_valid = false;
400 name_table_uninit(void)
402 rtnetlink_link_notifier_destroy(name_notifier);
403 name_notifier = NULL;
405 hmap_destroy(&name_map);
409 name_table_reset(void)
412 struct rtgenmsg *rtmsg;
413 uint64_t reply_stub[NL_DUMP_BUFSIZE / 8];
414 struct ofpbuf request, reply, buf;
416 name_table_valid = true;
419 ofpbuf_init(&request, 0);
420 nl_msg_put_nlmsghdr(&request, sizeof *rtmsg, RTM_GETLINK, NLM_F_REQUEST);
421 rtmsg = ofpbuf_put_zeros(&request, sizeof *rtmsg);
422 rtmsg->rtgen_family = AF_INET;
424 nl_dump_start(&dump, NETLINK_ROUTE, &request);
425 ofpbuf_uninit(&request);
427 ofpbuf_use_stub(&buf, reply_stub, sizeof reply_stub);
428 while (nl_dump_next(&dump, &reply, &buf)) {
429 struct rtnetlink_link_change change;
431 if (rtnetlink_link_parse(&reply, &change)
432 && change.nlmsg_type == RTM_NEWLINK
433 && !name_node_lookup(change.ifi_index)) {
434 struct name_node *nn;
436 nn = xzalloc(sizeof *nn);
437 nn->ifi_index = change.ifi_index;
438 ovs_strlcpy(nn->ifname, change.ifname, IFNAMSIZ);
439 hmap_insert(&name_map, &nn->node, hash_int(nn->ifi_index, 0));
443 return nl_dump_done(&dump);
447 name_table_change(const struct rtnetlink_link_change *change OVS_UNUSED,
448 void *aux OVS_UNUSED)
450 /* Changes to interface status can cause routing table changes that some
451 * versions of the linux kernel do not advertise for some reason. */
452 route_table_valid = false;
453 name_table_valid = false;
456 static struct name_node *
457 name_node_lookup(int ifi_index)
459 struct name_node *nn;
461 HMAP_FOR_EACH_WITH_HASH(nn, node, hash_int(ifi_index, 0), &name_map) {
462 if (nn->ifi_index == ifi_index) {
473 struct name_node *nn, *nn_next;
475 HMAP_FOR_EACH_SAFE(nn, nn_next, node, &name_map) {
476 hmap_remove(&name_map, &nn->node);