lib/route-table.c

   1 /*
   2  * Copyright (c) 2011, 2012, 2013, 2014, 2017 Nicira, Inc.
   3  *
   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:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  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.
  15  */
  16
  17 #include <config.h>
  18
  19 #include "route-table.h"
  20
  21 #include <errno.h>
  22 #include <sys/types.h>
  23 #include <netinet/in.h>
  24 #include <arpa/inet.h>
  25 #include <sys/socket.h>
  26 #include <linux/rtnetlink.h>
  27 #include <net/if.h>
  28
  29 #include "hash.h"
  30 #include "netdev.h"
  31 #include "netlink.h"
  32 #include "netlink-notifier.h"
  33 #include "netlink-socket.h"
  34 #include "openvswitch/ofpbuf.h"
  35 #include "ovs-router.h"
  36 #include "packets.h"
  37 #include "rtnetlink.h"
  38 #include "tnl-ports.h"
  39 #include "openvswitch/vlog.h"
  40
  41 /* Linux 2.6.36 added RTA_MARK, so define it just in case we're building with
  42  * old headers.  (We can't test for it with #ifdef because it's an enum.) */
  43 #define RTA_MARK 16
  44
  45 VLOG_DEFINE_THIS_MODULE(route_table);
  46
  47 struct route_data {
  48     /* Copied from struct rtmsg. */
  49     unsigned char rtm_dst_len;
  50
  51     /* Extracted from Netlink attributes. */
  52     struct in6_addr rta_dst; /* 0 if missing. */
  53     struct in6_addr rta_gw;
  54     char ifname[IFNAMSIZ]; /* Interface name. */
  55     uint32_t mark;
  56 };
  57
  58 /* A digested version of a route message sent down by the kernel to indicate
  59  * that a route has changed. */
  60 struct route_table_msg {
  61     bool relevant;        /* Should this message be processed? */
  62     int nlmsg_type;       /* e.g. RTM_NEWROUTE, RTM_DELROUTE. */
  63     struct route_data rd; /* Data parsed from this message. */
  64 };
  65
  66 static struct ovs_mutex route_table_mutex = OVS_MUTEX_INITIALIZER;
  67 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
  68
  69 /* Global change number for route-table, which should be incremented
  70  * every time route_table_reset() is called.  */
  71 static uint64_t rt_change_seq;
  72
  73 static struct nln *nln = NULL;
  74 static struct route_table_msg rtmsg;
  75 static struct nln_notifier *route_notifier = NULL;
  76 static struct nln_notifier *route6_notifier = NULL;
  77 static struct nln_notifier *name_notifier = NULL;
  78
  79 static bool route_table_valid = false;
  80
  81 static int route_table_reset(void);
  82 static void route_table_handle_msg(const struct route_table_msg *);
  83 static int route_table_parse(struct ofpbuf *, struct route_table_msg *);
  84 static void route_table_change(const struct route_table_msg *, void *);
  85 static void route_map_clear(void);
  86
  87 static void name_table_init(void);
  88 static void name_table_change(const struct rtnetlink_change *, void *);
  89
  90 uint64_t
  91 route_table_get_change_seq(void)
  92 {
  93     return rt_change_seq;
  94 }
  95
  96 /* Users of the route_table module should register themselves with this
  97  * function before making any other route_table function calls. */
  98 void
  99 route_table_init(void)
 100     OVS_EXCLUDED(route_table_mutex)
 101 {
 102     ovs_mutex_lock(&route_table_mutex);
 103     ovs_assert(!nln);
 104     ovs_assert(!route_notifier);
 105     ovs_assert(!route6_notifier);
 106
 107     ovs_router_init();
 108     nln = nln_create(NETLINK_ROUTE, (nln_parse_func *) route_table_parse,
 109                      &rtmsg);
 110
 111     route_notifier =
 112         nln_notifier_create(nln, RTNLGRP_IPV4_ROUTE,
 113                             (nln_notify_func *) route_table_change, NULL);
 114     route6_notifier =
 115         nln_notifier_create(nln, RTNLGRP_IPV6_ROUTE,
 116                             (nln_notify_func *) route_table_change, NULL);
 117
 118     route_table_reset();
 119     name_table_init();
 120
 121     ovs_mutex_unlock(&route_table_mutex);
 122 }
 123
 124 /* Run periodically to update the locally maintained routing table. */
 125 void
 126 route_table_run(void)
 127     OVS_EXCLUDED(route_table_mutex)
 128 {
 129     ovs_mutex_lock(&route_table_mutex);
 130     if (nln) {
 131         rtnetlink_run();
 132         nln_run(nln);
 133
 134         if (!route_table_valid) {
 135             route_table_reset();
 136         }
 137     }
 138     ovs_mutex_unlock(&route_table_mutex);
 139 }
 140
 141 /* Causes poll_block() to wake up when route_table updates are required. */
 142 void
 143 route_table_wait(void)
 144     OVS_EXCLUDED(route_table_mutex)
 145 {
 146     ovs_mutex_lock(&route_table_mutex);
 147     if (nln) {
 148         rtnetlink_wait();
 149         nln_wait(nln);
 150     }
 151     ovs_mutex_unlock(&route_table_mutex);
 152 }
 153
 154 static int
 155 route_table_reset(void)
 156 {
 157     struct nl_dump dump;
 158     struct rtgenmsg *rtmsg;
 159     uint64_t reply_stub[NL_DUMP_BUFSIZE / 8];
 160     struct ofpbuf request, reply, buf;
 161
 162     route_map_clear();
 163     netdev_get_addrs_list_flush();
 164     route_table_valid = true;
 165     rt_change_seq++;
 166
 167     ofpbuf_init(&request, 0);
 168
 169     nl_msg_put_nlmsghdr(&request, sizeof *rtmsg, RTM_GETROUTE, NLM_F_REQUEST);
 170
 171     rtmsg = ofpbuf_put_zeros(&request, sizeof *rtmsg);
 172     rtmsg->rtgen_family = AF_UNSPEC;
 173
 174     nl_dump_start(&dump, NETLINK_ROUTE, &request);
 175     ofpbuf_uninit(&request);
 176
 177     ofpbuf_use_stub(&buf, reply_stub, sizeof reply_stub);
 178     while (nl_dump_next(&dump, &reply, &buf)) {
 179         struct route_table_msg msg;
 180
 181         if (route_table_parse(&reply, &msg)) {
 182             route_table_handle_msg(&msg);
 183         }
 184     }
 185     ofpbuf_uninit(&buf);
 186
 187     return nl_dump_done(&dump);
 188 }
 189
 190 /* Return RTNLGRP_IPV4_ROUTE or RTNLGRP_IPV6_ROUTE on success, 0 on parse
 191  * error. */
 192 static int
 193 route_table_parse(struct ofpbuf *buf, struct route_table_msg *change)
 194 {
 195     bool parsed, ipv4 = false;
 196
 197     static const struct nl_policy policy[] = {
 198         [RTA_DST] = { .type = NL_A_U32, .optional = true  },
 199         [RTA_OIF] = { .type = NL_A_U32, .optional = true },
 200         [RTA_GATEWAY] = { .type = NL_A_U32, .optional = true },
 201         [RTA_MARK] = { .type = NL_A_U32, .optional = true },
 202     };
 203
 204     static const struct nl_policy policy6[] = {
 205         [RTA_DST] = { .type = NL_A_IPV6, .optional = true },
 206         [RTA_OIF] = { .type = NL_A_U32, .optional = true },
 207         [RTA_MARK] = { .type = NL_A_U32, .optional = true },
 208         [RTA_GATEWAY] = { .type = NL_A_IPV6, .optional = true },
 209     };
 210
 211     struct nlattr *attrs[ARRAY_SIZE(policy)];
 212     const struct rtmsg *rtm;
 213
 214     rtm = ofpbuf_at(buf, NLMSG_HDRLEN, sizeof *rtm);
 215
 216     if (rtm->rtm_family == AF_INET) {
 217         parsed = nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct rtmsg),
 218                                  policy, attrs, ARRAY_SIZE(policy));
 219         ipv4 = true;
 220     } else if (rtm->rtm_family == AF_INET6) {
 221         parsed = nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct rtmsg),
 222                                  policy6, attrs, ARRAY_SIZE(policy6));
 223     } else {
 224         VLOG_DBG_RL(&rl, "received non AF_INET rtnetlink route message");
 225         return 0;
 226     }
 227
 228     if (parsed) {
 229         const struct nlmsghdr *nlmsg;
 230         int rta_oif;      /* Output interface index. */
 231
 232         nlmsg = buf->data;
 233
 234         memset(change, 0, sizeof *change);
 235         change->relevant = true;
 236
 237         if (rtm->rtm_scope == RT_SCOPE_NOWHERE) {
 238             change->relevant = false;
 239         }
 240
 241         if (rtm->rtm_type != RTN_UNICAST &&
 242             rtm->rtm_type != RTN_LOCAL) {
 243             change->relevant = false;
 244         }
 245         change->nlmsg_type     = nlmsg->nlmsg_type;
 246         change->rd.rtm_dst_len = rtm->rtm_dst_len + (ipv4 ? 96 : 0);
 247         if (attrs[RTA_OIF]) {
 248             rta_oif = nl_attr_get_u32(attrs[RTA_OIF]);
 249
 250             if (!if_indextoname(rta_oif, change->rd.ifname)) {
 251                 int error = errno;
 252
 253                 VLOG_DBG_RL(&rl, "Could not find interface name[%u]: %s",
 254                             rta_oif, ovs_strerror(error));
 255                 if (error == ENXIO) {
 256                     change->relevant = false;
 257                 } else {
 258                     return 0;
 259                 }
 260             }
 261         }
 262
 263         if (attrs[RTA_DST]) {
 264             if (ipv4) {
 265                 ovs_be32 dst;
 266                 dst = nl_attr_get_be32(attrs[RTA_DST]);
 267                 in6_addr_set_mapped_ipv4(&change->rd.rta_dst, dst);
 268             } else {
 269                 change->rd.rta_dst = nl_attr_get_in6_addr(attrs[RTA_DST]);
 270             }
 271         } else if (ipv4) {
 272             in6_addr_set_mapped_ipv4(&change->rd.rta_dst, 0);
 273         }
 274         if (attrs[RTA_GATEWAY]) {
 275             if (ipv4) {
 276                 ovs_be32 gw;
 277                 gw = nl_attr_get_be32(attrs[RTA_GATEWAY]);
 278                 in6_addr_set_mapped_ipv4(&change->rd.rta_gw, gw);
 279             } else {
 280                 change->rd.rta_gw = nl_attr_get_in6_addr(attrs[RTA_GATEWAY]);
 281             }
 282         }
 283         if (attrs[RTA_MARK]) {
 284             change->rd.mark = nl_attr_get_u32(attrs[RTA_MARK]);
 285         }
 286     } else {
 287         VLOG_DBG_RL(&rl, "received unparseable rtnetlink route message");
 288         return 0;
 289     }
 290
 291     /* Success. */
 292     return ipv4 ? RTNLGRP_IPV4_ROUTE : RTNLGRP_IPV6_ROUTE;
 293 }
 294
 295 static void
 296 route_table_change(const struct route_table_msg *change OVS_UNUSED,
 297                    void *aux OVS_UNUSED)
 298 {
 299     route_table_valid = false;
 300 }
 301
 302 static void
 303 route_table_handle_msg(const struct route_table_msg *change)
 304 {
 305     if (change->relevant && change->nlmsg_type == RTM_NEWROUTE) {
 306         const struct route_data *rd = &change->rd;
 307
 308         ovs_router_insert(rd->mark, &rd->rta_dst, rd->rtm_dst_len,
 309                           rd->ifname, &rd->rta_gw);
 310     }
 311 }
 312
 313 static void
 314 route_map_clear(void)
 315 {
 316     ovs_router_flush();
 317 }
 318
 319 bool
 320 route_table_fallback_lookup(const struct in6_addr *ip6_dst OVS_UNUSED,
 321                             char name[] OVS_UNUSED,
 322                             struct in6_addr *gw6)
 323 {
 324     *gw6 = in6addr_any;
 325     return false;
 326 }
 327
 328 \f
 329 /* name_table . */
 330
 331 static void
 332 name_table_init(void)
 333 {
 334     name_notifier = rtnetlink_notifier_create(name_table_change, NULL);
 335 }
 336
 337
 338 static void
 339 name_table_change(const struct rtnetlink_change *change,
 340                   void *aux OVS_UNUSED)
 341 {
 342     /* Changes to interface status can cause routing table changes that some
 343      * versions of the linux kernel do not advertise for some reason. */
 344     route_table_valid = false;
 345
 346     if (change && change->nlmsg_type == RTM_DELLINK) {
 347         if (change->ifname) {
 348             tnl_port_map_delete_ipdev(change->ifname);
 349         }
 350     }
 351 }