text: /*
   * Copyright (c) 2011, 2012, 2013, 2014 Nicira, Inc.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at:
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include <config.h>
  
  #include "route-table.h"
  
  #include <errno.h>
  #include <arpa/inet.h>
  #include <sys/socket.h>
  #include <linux/rtnetlink.h>
  #include <net/if.h>
  
  #include "hash.h"
  #include "netlink.h"
  #include "netlink-notifier.h"
  #include "netlink-socket.h"
  #include "ofpbuf.h"
  #include "ovs-router.h"
  #include "packets.h"
  #include "rtnetlink.h"
  #include "openvswitch/vlog.h"
  
  VLOG_DEFINE_THIS_MODULE(route_table);
  
  struct route_data {
      /* Copied from struct rtmsg. */
      unsigned char rtm_dst_len;
  
      /* Extracted from Netlink attributes. */
      struct in6_addr rta_dst; /* 0 if missing. */
      struct in6_addr rta_gw;
      char ifname[IFNAMSIZ]; /* Interface name. */
  };
  
  /* A digested version of a route message sent down by the kernel to indicate
   * that a route has changed. */
  struct route_table_msg {
      bool relevant;        /* Should this message be processed? */
      int nlmsg_type;       /* e.g. RTM_NEWROUTE, RTM_DELROUTE. */
      struct route_data rd; /* Data parsed from this message. */
  };
  
  static struct ovs_mutex route_table_mutex = OVS_MUTEX_INITIALIZER;
  static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
  
  /* Global change number for route-table, which should be incremented
   * every time route_table_reset() is called.  */
  static uint64_t rt_change_seq;
  
  static struct nln *nln = NULL;
  static struct nln *nln6 = NULL;
  static struct route_table_msg rtmsg;
  static struct nln_notifier *route_notifier = NULL;
  static struct nln_notifier *route6_notifier = NULL;
  static struct nln_notifier *name_notifier = NULL;
  
  static bool route_table_valid = false;
  
  static int route_table_reset(void);
  static void route_table_handle_msg(const struct route_table_msg *);
  static bool route_table_parse(struct ofpbuf *, struct route_table_msg *);
  static void route_table_change(const struct route_table_msg *, void *);
  static void route_map_clear(void);
  
  static void name_table_init(void);
  static void name_table_change(const struct rtnetlink_change *, void *);
  
  uint64_t
  route_table_get_change_seq(void)
  {
      return rt_change_seq;
  }
  
  /* Users of the route_table module should register themselves with this
   * function before making any other route_table function calls. */
  void
  route_table_init(void)
      OVS_EXCLUDED(route_table_mutex)
  {
      ovs_mutex_lock(&route_table_mutex);
      ovs_assert(!nln);
      ovs_assert(!nln6);
      ovs_assert(!route_notifier);
      ovs_assert(!route6_notifier);
  
      ovs_router_init();
      nln = nln_create(NETLINK_ROUTE, RTNLGRP_IPV4_ROUTE,
                       (nln_parse_func *) route_table_parse, &rtmsg);
      nln6 = nln_create(NETLINK_ROUTE, RTNLGRP_IPV6_ROUTE,
                        (nln_parse_func *) route_table_parse, &rtmsg);
  
      route_notifier =
          nln_notifier_create(nln, (nln_notify_func *) route_table_change,
                              NULL);
      route6_notifier =
          nln_notifier_create(nln6, (nln_notify_func *) route_table_change,
                              NULL);
  
      route_table_reset();
      name_table_init();
  
      ovs_mutex_unlock(&route_table_mutex);
  }
  
  /* Run periodically to update the locally maintained routing table. */
  void
  route_table_run(void)
      OVS_EXCLUDED(route_table_mutex)
  {
      ovs_mutex_lock(&route_table_mutex);
      if (nln || nln6) {
          rtnetlink_run();
          if (nln) {
              nln_run(nln);
          }
          if (nln6) {
              nln_run(nln6);
          }
  
          if (!route_table_valid) {
              route_table_reset();
          }
      }
      ovs_mutex_unlock(&route_table_mutex);
  }
  
  /* Causes poll_block() to wake up when route_table updates are required. */
  void
  route_table_wait(void)
      OVS_EXCLUDED(route_table_mutex)
  {
      ovs_mutex_lock(&route_table_mutex);
      if (nln || nln6) {
          rtnetlink_wait();
          if (nln) {
              nln_wait(nln);
          }
          if (nln6) {
              nln_wait(nln6);
          }
      }
      ovs_mutex_unlock(&route_table_mutex);
  }
  
  static int
  route_table_reset(void)
  {
      struct nl_dump dump;
      struct rtgenmsg *rtmsg;
      uint64_t reply_stub[NL_DUMP_BUFSIZE / 8];
      struct ofpbuf request, reply, buf;
  
      route_map_clear();
      route_table_valid = true;
      rt_change_seq++;
  
      ofpbuf_init(&request, 0);
  
      nl_msg_put_nlmsghdr(&request, sizeof *rtmsg, RTM_GETROUTE, NLM_F_REQUEST);
  
      rtmsg = ofpbuf_put_zeros(&request, sizeof *rtmsg);
      rtmsg->rtgen_family = AF_UNSPEC;
  
      nl_dump_start(&dump, NETLINK_ROUTE, &request);
      ofpbuf_uninit(&request);
  
      ofpbuf_use_stub(&buf, reply_stub, sizeof reply_stub);
      while (nl_dump_next(&dump, &reply, &buf)) {
          struct route_table_msg msg;
  
          if (route_table_parse(&reply, &msg)) {
              route_table_handle_msg(&msg);
          }
      }
      ofpbuf_uninit(&buf);
  
      return nl_dump_done(&dump);
  }
  
  static bool
  route_table_parse(struct ofpbuf *buf, struct route_table_msg *change)
  {
      bool parsed, ipv4 = false;
  
      static const struct nl_policy policy[] = {
          [RTA_DST] = { .type = NL_A_U32, .optional = true  },
          [RTA_OIF] = { .type = NL_A_U32, .optional = false },
          [RTA_GATEWAY] = { .type = NL_A_U32, .optional = true },
      };
  
      static const struct nl_policy policy6[] = {
          [RTA_DST] = { .type = NL_A_IPV6, .optional = true },
          [RTA_OIF] = { .type = NL_A_U32, .optional = true },
          [RTA_GATEWAY] = { .type = NL_A_IPV6, .optional = true },
      };
  
      struct nlattr *attrs[ARRAY_SIZE(policy)];
      const struct rtmsg *rtm;
  
      rtm = ofpbuf_at(buf, NLMSG_HDRLEN, sizeof *rtm);
  
      if (rtm->rtm_family == AF_INET) {
          parsed = nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct rtmsg),
                                   policy, attrs, ARRAY_SIZE(policy));
          ipv4 = true;
      } else if (rtm->rtm_family == AF_INET6) {
          parsed = nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct rtmsg),
                                   policy6, attrs, ARRAY_SIZE(policy6));
      } else {
          VLOG_DBG_RL(&rl, "received non AF_INET rtnetlink route message");
          return false;
      }
  
      if (parsed) {
          const struct nlmsghdr *nlmsg;
          int rta_oif;      /* Output interface index. */
  
          nlmsg = buf->data;
  
          memset(change, 0, sizeof *change);
          change->relevant = true;
  
          if (rtm->rtm_scope == RT_SCOPE_NOWHERE) {
              change->relevant = false;
          }
  
          if (rtm->rtm_type != RTN_UNICAST &&
              rtm->rtm_type != RTN_LOCAL) {
              change->relevant = false;
          }
          change->nlmsg_type     = nlmsg->nlmsg_type;
          change->rd.rtm_dst_len = rtm->rtm_dst_len + (ipv4 ? 96 : 0);
          if (attrs[RTA_OIF]) {
              rta_oif = nl_attr_get_u32(attrs[RTA_OIF]);
  
              if (!if_indextoname(rta_oif, change->rd.ifname)) {
                  int error = errno;
  
                  VLOG_DBG_RL(&rl, "Could not find interface name[%u]: %s",
                              rta_oif, ovs_strerror(error));
                  if (error == ENXIO) {
                      change->relevant = false;
                  } else {
                      return false;
                  }
              }
          }
  
          if (attrs[RTA_DST]) {
              if (ipv4) {
                  ovs_be32 dst;
                  dst = nl_attr_get_be32(attrs[RTA_DST]);
                  in6_addr_set_mapped_ipv4(&change->rd.rta_dst, dst);
              } else {
                  change->rd.rta_dst = nl_attr_get_in6_addr(attrs[RTA_DST]);
              }
          } else if (ipv4) {
              in6_addr_set_mapped_ipv4(&change->rd.rta_dst, 0);
          }
          if (attrs[RTA_GATEWAY]) {
              if (ipv4) {
                  ovs_be32 gw;
                  gw = nl_attr_get_be32(attrs[RTA_GATEWAY]);
                  in6_addr_set_mapped_ipv4(&change->rd.rta_gw, gw);
              } else {
                  change->rd.rta_gw = nl_attr_get_in6_addr(attrs[RTA_GATEWAY]);
              }
          }
  
  
      } else {
          VLOG_DBG_RL(&rl, "received unparseable rtnetlink route message");
      }
  
      return parsed;
  }
  
  static void
  route_table_change(const struct route_table_msg *change OVS_UNUSED,
                     void *aux OVS_UNUSED)
  {
      route_table_valid = false;
  }
  
  static void
  route_table_handle_msg(const struct route_table_msg *change)
  {
      if (change->relevant && change->nlmsg_type == RTM_NEWROUTE) {
          const struct route_data *rd = &change->rd;
  
          ovs_router_insert(&rd->rta_dst, rd->rtm_dst_len,
                            rd->ifname, &rd->rta_gw);
      }
  }
  
  static void
  route_map_clear(void)
  {
      ovs_router_flush();
  }
  
  bool
  route_table_fallback_lookup(ovs_be32 ip_dst OVS_UNUSED,
                              char output_bridge[] OVS_UNUSED,
                              ovs_be32 *gw)
  {
      *gw = 0;
      return false;
  }
  
  
  /* name_table . */
  
  static void
  name_table_init(void)
  {
      name_notifier = rtnetlink_notifier_create(name_table_change, NULL);
  }
  
  
  static void
  name_table_change(const struct rtnetlink_change *change OVS_UNUSED,
                    void *aux OVS_UNUSED)
  {
      /* Changes to interface status can cause routing table changes that some
       * versions of the linux kernel do not advertise for some reason. */
      route_table_valid = false;
  }
  