2 * Copyright (c) 2011 Nicira Networks.
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"
22 #include <arpa/inet.h>
23 #include <sys/socket.h>
24 #include <linux/rtnetlink.h>
30 #include "netlink-socket.h"
32 #include "rtnetlink.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. */
59 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
61 static unsigned int register_count = 0;
62 static struct rtnetlink *rtn = NULL;
63 static struct route_table_msg rtmsg;
64 static struct rtnetlink_notifier notifier;
66 static bool route_table_valid = false;
67 static struct hmap route_map;
69 static int route_table_reset(void);
70 static void route_table_handle_msg(const struct route_table_msg *);
71 static bool route_table_parse(struct ofpbuf *, struct route_table_msg *);
72 static void route_table_change(const struct route_table_msg *, void *);
73 static struct route_node *route_node_lookup(const struct route_data *);
74 static struct route_node *route_node_lookup_by_ip(uint32_t ip);
75 static void route_map_clear(void);
76 static uint32_t hash_route_data(const struct route_data *);
78 /* Populates 'ifindex' with the interface index traffic destined for 'ip' is
79 * likely to egress. There is no hard guarantee that traffic destined for 'ip'
80 * will egress out the specified interface. 'ifindex' may refer to an
81 * interface which is not physical (such as a bridge port).
83 * Returns true if successful, otherwise false. */
85 route_table_get_ifindex(ovs_be32 ip_, int *ifindex)
87 struct route_node *rn;
88 uint32_t ip = ntohl(ip_);
92 if (!route_table_valid) {
96 rn = route_node_lookup_by_ip(ip);
99 *ifindex = rn->rd.rta_oif;
103 /* Choose a default route. */
104 HMAP_FOR_EACH(rn, node, &route_map) {
105 if (rn->rd.rta_dst == 0 && rn->rd.rtm_dst_len == 0) {
106 *ifindex = rn->rd.rta_oif;
114 /* Users of the route_table module should register themselves with this
115 * function before making any other route_table function calls. */
117 route_table_register(void)
119 if (!register_count) {
120 rtnetlink_parse_func *pf;
121 rtnetlink_notify_func *nf;
125 pf = (rtnetlink_parse_func *) route_table_parse;
126 nf = (rtnetlink_notify_func *) route_table_change;
128 rtn = rtnetlink_create(RTNLGRP_IPV4_ROUTE, pf, &rtmsg);
129 rtnetlink_notifier_register(rtn, ¬ifier, nf, NULL);
131 hmap_init(&route_map);
138 /* Users of the route_table module should unregister themselves with this
139 * function when they will no longer be making any more route_table fuction
142 route_table_unregister(void)
146 if (!register_count) {
147 rtnetlink_destroy(rtn);
151 hmap_destroy(&route_map);
155 /* Run periodically to update the locally maintained routing table. */
157 route_table_run(void)
160 rtnetlink_notifier_run(rtn);
164 /* Causes poll_block() to wake up when route_table updates are required. */
166 route_table_wait(void)
169 rtnetlink_notifier_wait(rtn);
174 route_table_reset(void)
178 struct rtgenmsg *rtmsg;
179 struct ofpbuf request, reply;
180 static struct nl_sock *rtnl_sock;
183 route_table_valid = true;
185 error = nl_sock_create(NETLINK_ROUTE, 0, 0, 0, &rtnl_sock);
187 VLOG_WARN_RL(&rl, "failed to reset routing table, "
188 "cannot create RTNETLINK_ROUTE socket");
192 ofpbuf_init(&request, 0);
194 nl_msg_put_nlmsghdr(&request, sizeof *rtmsg, RTM_GETROUTE, NLM_F_REQUEST);
196 rtmsg = ofpbuf_put_zeros(&request, sizeof *rtmsg);
197 rtmsg->rtgen_family = AF_INET;
199 nl_dump_start(&dump, rtnl_sock, &request);
201 while (nl_dump_next(&dump, &reply)) {
202 struct route_table_msg msg;
204 if (route_table_parse(&reply, &msg)) {
205 route_table_handle_msg(&msg);
209 error = nl_dump_done(&dump);
210 nl_sock_destroy(rtnl_sock);
217 route_table_parse(struct ofpbuf *buf, struct route_table_msg *change)
221 static const struct nl_policy policy[] = {
222 [RTA_DST] = { .type = NL_A_U32, .optional = true },
223 [RTA_OIF] = { .type = NL_A_U32, .optional = false },
226 static struct nlattr *attrs[ARRAY_SIZE(policy)];
228 parsed = nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct rtmsg),
229 policy, attrs, ARRAY_SIZE(policy));
232 const struct rtmsg *rtm;
233 const struct nlmsghdr *nlmsg;
236 rtm = (const struct rtmsg *) ((const char *) buf->data + NLMSG_HDRLEN);
238 if (rtm->rtm_family != AF_INET) {
239 VLOG_DBG_RL(&rl, "received non AF_INET rtnetlink route message");
243 memset(change, 0, sizeof *change);
244 change->relevant = true;
246 if (rtm->rtm_scope == RT_SCOPE_NOWHERE) {
247 change->relevant = false;
250 if (rtm->rtm_type != RTN_UNICAST &&
251 rtm->rtm_type != RTN_LOCAL) {
252 change->relevant = false;
255 change->nlmsg_type = nlmsg->nlmsg_type;
256 change->rd.rtm_dst_len = rtm->rtm_dst_len;
257 change->rd.rta_oif = nl_attr_get_u32(attrs[RTA_OIF]);
259 if (attrs[RTA_DST]) {
260 change->rd.rta_dst = ntohl(nl_attr_get_be32(attrs[RTA_DST]));
264 VLOG_DBG_RL(&rl, "received unparseable rtnetlink route message");
271 route_table_change(const struct route_table_msg *change OVS_UNUSED,
272 void *aux OVS_UNUSED)
274 route_table_valid = false;
278 route_table_handle_msg(const struct route_table_msg *change)
280 if (change->relevant && change->nlmsg_type == RTM_NEWROUTE &&
281 !route_node_lookup(&change->rd)) {
282 struct route_node *rn;
284 rn = xzalloc(sizeof *rn);
285 memcpy(&rn->rd, &change->rd, sizeof change->rd);
287 hmap_insert(&route_map, &rn->node, hash_route_data(&rn->rd));
291 static struct route_node *
292 route_node_lookup(const struct route_data *rd)
294 struct route_node *rn;
296 HMAP_FOR_EACH_WITH_HASH(rn, node, hash_route_data(rd), &route_map) {
297 if (!memcmp(&rn->rd, rd, sizeof *rd)) {
305 static struct route_node *
306 route_node_lookup_by_ip(uint32_t ip)
309 struct route_node *rn, *rn_ret;
314 HMAP_FOR_EACH(rn, node, &route_map) {
315 uint32_t mask = 0xffffffff << (32 - rn->rd.rtm_dst_len);
317 if (rn->rd.rta_dst == 0 && rn->rd.rtm_dst_len == 0) {
322 if (rn->rd.rtm_dst_len > dst_len &&
323 (ip & mask) == (rn->rd.rta_dst & mask)) {
325 dst_len = rn->rd.rtm_dst_len;
333 route_map_clear(void)
335 struct route_node *rn, *rn_next;
337 HMAP_FOR_EACH_SAFE(rn, rn_next, node, &route_map) {
338 hmap_remove(&route_map, &rn->node);
344 hash_route_data(const struct route_data *rd)
346 return hash_bytes(rd, sizeof *rd, 0);