lib/route-table-bsd.c

   1 /*
   2  * Copyright (c) 2012 Ed Maste. All rights reserved.
   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 <sys/socket.h>
  22 #include <sys/types.h>
  23
  24 #include <net/if.h>
  25 #include <net/route.h>
  26 #include <net/if_dl.h>
  27 #include <netinet/in.h>
  28
  29 #include <errno.h>
  30 #include <poll.h>
  31 #include <string.h>
  32 #include <unistd.h>
  33
  34 #include "ovs-router.h"
  35 #include "packets.h"
  36 #include "openvswitch/vlog.h"
  37 #include "util.h"
  38
  39 VLOG_DEFINE_THIS_MODULE(route_table_bsd);
  40
  41 /* OS X does not define RT_ROUNDUP() or equivalent macro. */
  42 #if defined(__MACH__)
  43 #define RT_ROUNDUP(l) ((l) > 0 ? ROUND_UP((l), sizeof(long)) : sizeof(long))
  44 #endif
  45
  46 bool
  47 route_table_fallback_lookup(const struct in6_addr *ip6_dst, char name[],
  48                             struct in6_addr *gw6)
  49 {
  50     ovs_be32 ip;
  51     struct {
  52         struct rt_msghdr rtm;
  53         char space[512];
  54     } rtmsg;
  55
  56     struct rt_msghdr *rtm = &rtmsg.rtm;
  57     struct sockaddr_dl *ifp = NULL;
  58     struct sockaddr_in *sin;
  59     struct sockaddr *sa;
  60     static int seq;
  61     int i, namelen, rtsock;
  62     ssize_t len;
  63     const pid_t pid = getpid();
  64     bool got_ifp = false;
  65     unsigned int retry_count = 5;  /* arbitrary */
  66
  67     if (!IN6_IS_ADDR_V4MAPPED(ip6_dst)) {
  68         return false;
  69     }
  70     ip = in6_addr_get_mapped_ipv4(ip6_dst);
  71
  72     VLOG_DBG("looking route up for " IP_FMT " pid %" PRIuMAX,
  73         IP_ARGS(ip), (uintmax_t)pid);
  74
  75     rtsock = socket(PF_ROUTE, SOCK_RAW, 0);
  76     if (rtsock < 0)
  77         return false;
  78
  79 retry:
  80     memset(&rtmsg, 0, sizeof(rtmsg));
  81     rtm->rtm_msglen = sizeof(struct rt_msghdr) + sizeof(struct sockaddr_in);
  82     rtm->rtm_version = RTM_VERSION;
  83     rtm->rtm_type = RTM_GET;
  84     rtm->rtm_addrs = RTA_DST | RTA_IFP;
  85     rtm->rtm_seq = ++seq;
  86
  87     sin = (struct sockaddr_in *)(rtm + 1);
  88     sin->sin_len = len = sizeof(struct sockaddr_in);
  89     sin->sin_family = AF_INET;
  90     sin->sin_addr.s_addr = ip;
  91
  92     len = write(rtsock, (char *)&rtmsg, rtm->rtm_msglen);
  93     if (len == -1) {
  94         if (errno == ENOBUFS && retry_count-- > 0) {
  95             VLOG_INFO("Recoverable error writing to routing socket: %s",
  96                       ovs_strerror(errno));
  97             usleep(500 * 1000);  /* arbitrary */
  98             goto retry;
  99         }
 100         VLOG_ERR("Error writing to routing socket: %s", ovs_strerror(errno));
 101         close(rtsock);
 102         return false;
 103     }
 104     if (len != rtm->rtm_msglen) {
 105         VLOG_ERR("Short write to routing socket");
 106         close(rtsock);
 107         return false;
 108     }
 109
 110     do {
 111         struct pollfd pfd;
 112         int ret;
 113
 114         memset(&pfd, 0, sizeof(pfd));
 115         pfd.fd = rtsock;
 116         pfd.events = POLLIN;
 117         /*
 118          * The timeout value below is somehow arbitrary.
 119          * It's to detect the lost of routing messages due to
 120          * buffer exhaustion etc.  The routing socket is not
 121          * reliable.
 122          */
 123         ret = poll(&pfd, 1, 500);
 124         if (ret == -1) {
 125             VLOG_ERR("Error polling on routing socket: %s",
 126                      ovs_strerror(errno));
 127             close(rtsock);
 128             return false;
 129         }
 130         if (ret == 0) {
 131             if (retry_count-- > 0) {
 132                 VLOG_INFO("Timeout; resending routing message");
 133                 goto retry;
 134             }
 135             close(rtsock);
 136             return false;
 137         }
 138         len = read(rtsock, (char *)&rtmsg, sizeof(rtmsg));
 139         if (len > 0) {
 140             VLOG_DBG("got rtmsg pid %" PRIuMAX " seq %d",
 141                 (uintmax_t)rtmsg.rtm.rtm_pid,
 142                 rtmsg.rtm.rtm_seq);
 143         }
 144     } while (len > 0 && (rtmsg.rtm.rtm_seq != seq ||
 145         rtmsg.rtm.rtm_pid != pid));
 146     close(rtsock);
 147     if (len == -1) {
 148         VLOG_ERR("Error reading from routing socket: %s", ovs_strerror(errno));
 149         return false;
 150     }
 151
 152     *gw6 = in6addr_any;
 153     sa = (struct sockaddr *)(rtm + 1);
 154     for (i = 1; i; i <<= 1) {
 155         if (rtm->rtm_addrs & i) {
 156             if (i == RTA_IFP && sa->sa_family == AF_LINK &&
 157               ALIGNED_CAST(struct sockaddr_dl *, sa)->sdl_nlen) {
 158                 ifp = ALIGNED_CAST(struct sockaddr_dl *, sa);
 159                 namelen = ifp->sdl_nlen;
 160                 if (namelen > IFNAMSIZ - 1)
 161                     namelen = IFNAMSIZ - 1;
 162                 memcpy(name, ifp->sdl_data, namelen);
 163                 name[namelen] = '\0';
 164                 VLOG_DBG("got ifp %s", name);
 165                 got_ifp = true;
 166             } else if (i == RTA_GATEWAY && sa->sa_family == AF_INET) {
 167                 const struct sockaddr_in *sin_dst =
 168                     ALIGNED_CAST(struct sockaddr_in *, sa);
 169
 170                 in6_addr_set_mapped_ipv4(gw6, sin_dst->sin_addr.s_addr);
 171                 VLOG_DBG("got gateway " IP_FMT, IP_ARGS(sin_dst->sin_addr.s_addr));
 172             }
 173 #if defined(__FreeBSD__)
 174             sa = (struct sockaddr *)((char *)sa + SA_SIZE(sa));
 175 #elif defined(__NetBSD__)
 176             sa = (struct sockaddr *)((char *)sa + RT_ROUNDUP(sa->sa_len));
 177 #elif defined(__MACH__)
 178             sa = (struct sockaddr *)((char *)sa + RT_ROUNDUP(sa->sa_len));
 179 #else
 180 #error unimplemented
 181 #endif
 182         }
 183     }
 184     return got_ifp;
 185 }
 186
 187 uint64_t
 188 route_table_get_change_seq(void)
 189 {
 190     return 0;
 191 }
 192
 193 void
 194 route_table_init(void)
 195 {
 196     ovs_router_init();
 197 }
 198
 199 void
 200 route_table_run(void)
 201 {
 202 }
 203
 204 void
 205 route_table_wait(void)
 206 {
 207 }