pimd/pim_msdp_socket.c

   1 /*
   2  * IP MSDP socket management
   3  * Copyright (C) 2016 Cumulus Networks, Inc.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; see the file COPYING; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19
  20 #include <zebra.h>
  21
  22 #include <lib/log.h>
  23 #include <lib/network.h>
  24 #include <lib/sockunion.h>
  25 #include <lib/thread.h>
  26 #include <lib/vty.h>
  27
  28 #include "pimd.h"
  29
  30 #include "pim_msdp.h"
  31 #include "pim_msdp_socket.h"
  32
  33 /* increase socket send buffer size */
  34 static void
  35 pim_msdp_update_sock_send_buffer_size (int fd)
  36 {
  37   int size = PIM_MSDP_SOCKET_SNDBUF_SIZE;
  38   int optval;
  39   socklen_t optlen = sizeof(optval);
  40
  41   if (getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &optval, &optlen) < 0) {
  42     zlog_err("getsockopt of SO_SNDBUF failed %s\n", safe_strerror(errno));
  43     return;
  44   }
  45
  46   if (optval < size) {
  47     if (setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &size, sizeof(size)) < 0) {
  48       zlog_err("Couldn't increase send buffer: %s\n", safe_strerror(errno));
  49     }
  50   }
  51 }
  52
  53 /* passive peer socket accept */
  54 static int
  55 pim_msdp_sock_accept(struct thread *thread)
  56 {
  57   union sockunion su;
  58   struct pim_msdp_listener *listener = THREAD_ARG(thread);
  59   int accept_sock;
  60   int msdp_sock;
  61   struct pim_msdp_peer *mp;
  62   char buf[SU_ADDRSTRLEN];
  63
  64   sockunion_init(&su);
  65
  66   /* re-register accept thread */
  67   accept_sock = THREAD_FD(thread);
  68   if (accept_sock < 0) {
  69     zlog_err ("accept_sock is negative value %d", accept_sock);
  70     return -1;
  71   }
  72   listener->thread = NULL;
  73   thread_add_read(master, pim_msdp_sock_accept, listener, accept_sock,
  74                   &listener->thread);
  75
  76   /* accept client connection. */
  77   msdp_sock = sockunion_accept(accept_sock, &su);
  78   if (msdp_sock < 0) {
  79     zlog_err ("pim_msdp_sock_accept failed (%s)", safe_strerror (errno));
  80     return -1;
  81   }
  82
  83   /* see if have peer config for this */
  84   mp = pim_msdp_peer_find(su.sin.sin_addr);
  85   if (!mp || !PIM_MSDP_PEER_IS_LISTENER(mp)) {
  86     ++msdp->rejected_accepts;
  87     if (PIM_DEBUG_MSDP_EVENTS) {
  88       zlog_err("msdp peer connection refused from %s",
  89           sockunion2str(&su, buf, SU_ADDRSTRLEN));
  90     }
  91     close(msdp_sock);
  92     return -1;
  93   }
  94
  95   if (PIM_DEBUG_MSDP_INTERNAL) {
  96     zlog_debug("MSDP peer %s accept success%s", mp->key_str, mp->fd>=0?"(dup)":"");
  97   }
  98
  99   /* if we have an existing connection we need to kill that one
 100    * with this one */
 101   if (mp->fd >= 0) {
 102     if (PIM_DEBUG_MSDP_EVENTS) {
 103       zlog_err("msdp peer new connection from %s stop old connection",
 104           sockunion2str(&su, buf, SU_ADDRSTRLEN));
 105     }
 106     pim_msdp_peer_stop_tcp_conn(mp, true /* chg_state */);
 107   }
 108   mp->fd = msdp_sock;
 109   set_nonblocking(mp->fd);
 110   pim_msdp_update_sock_send_buffer_size(mp->fd);
 111   pim_msdp_peer_established(mp);
 112   return 0;
 113 }
 114
 115 /* global listener for the MSDP well know TCP port */
 116 int
 117 pim_msdp_sock_listen(void)
 118 {
 119   int sock;
 120   int socklen;
 121   struct sockaddr_in sin;
 122   int rc;
 123   struct pim_msdp_listener *listener = &msdp->listener;
 124
 125   if (msdp->flags & PIM_MSDPF_LISTENER) {
 126     /* listener already setup */
 127     return 0;
 128   }
 129
 130   sock = socket(AF_INET, SOCK_STREAM, 0);
 131   if (sock < 0) {
 132     zlog_err ("socket: %s", safe_strerror (errno));
 133     return sock;
 134   }
 135
 136   memset(&sin, 0, sizeof(struct sockaddr_in));
 137   sin.sin_family = AF_INET;
 138   sin.sin_port = htons(PIM_MSDP_TCP_PORT);
 139   socklen = sizeof(struct sockaddr_in);
 140 #ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
 141   sin.sin_len = socklen;
 142 #endif /* HAVE_STRUCT_SOCKADDR_IN_SIN_LEN */
 143
 144   sockopt_reuseaddr(sock);
 145   sockopt_reuseport(sock);
 146
 147   if (pimd_privs.change(ZPRIVS_RAISE)) {
 148     zlog_err ("pim_msdp_socket: could not raise privs, %s",
 149         safe_strerror (errno));
 150   }
 151
 152   /* bind to well known TCP port */
 153   rc = bind(sock, (struct sockaddr *)&sin, socklen);
 154
 155   if (pimd_privs.change(ZPRIVS_LOWER)) {
 156     zlog_err ("pim_msdp_socket: could not lower privs, %s",
 157         safe_strerror (errno));
 158   }
 159
 160   if (rc < 0) {
 161     zlog_err ("pim_msdp_socket bind to port %d: %s", ntohs(sin.sin_port), safe_strerror (errno));
 162     close(sock);
 163     return rc;
 164   }
 165
 166   rc = listen(sock, 3 /* backlog */);
 167   if (rc < 0) {
 168     zlog_err ("pim_msdp_socket listen: %s", safe_strerror (errno));
 169     close(sock);
 170     return rc;
 171   }
 172
 173   /* add accept thread */
 174   listener->fd = sock;
 175   memcpy(&listener->su, &sin, socklen);
 176   listener->thread = NULL;
 177   thread_add_read(msdp->master, pim_msdp_sock_accept, listener, sock,
 178                   &listener->thread);
 179
 180   msdp->flags |= PIM_MSDPF_LISTENER;
 181   return 0;
 182 }
 183
 184 /* active peer socket setup */
 185 int
 186 pim_msdp_sock_connect(struct pim_msdp_peer *mp)
 187 {
 188   int rc;
 189
 190   if (PIM_DEBUG_MSDP_INTERNAL) {
 191     zlog_debug("MSDP peer %s attempt connect%s", mp->key_str, mp->fd<0?"":"(dup)");
 192   }
 193
 194   /* if we have an existing connection we need to kill that one
 195    * with this one */
 196   if (mp->fd >= 0) {
 197     if (PIM_DEBUG_MSDP_EVENTS) {
 198       zlog_err("msdp duplicate connect to %s nuke old connection", mp->key_str);
 199     }
 200     pim_msdp_peer_stop_tcp_conn(mp, false /* chg_state */);
 201   }
 202
 203   /* Make socket for the peer. */
 204   mp->fd = sockunion_socket(&mp->su_peer);
 205   if (mp->fd < 0) {
 206     zlog_err ("pim_msdp_socket socket failure: %s", safe_strerror (errno));
 207     return -1;
 208   }
 209
 210   set_nonblocking(mp->fd);
 211
 212   /* Set socket send buffer size */
 213   pim_msdp_update_sock_send_buffer_size(mp->fd);
 214   sockopt_reuseaddr(mp->fd);
 215   sockopt_reuseport(mp->fd);
 216
 217   /* source bind */
 218   rc = sockunion_bind(mp->fd, &mp->su_local, 0, &mp->su_local);
 219   if (rc < 0) {
 220     zlog_err ("pim_msdp_socket connect bind failure: %s", safe_strerror (errno));
 221     close(mp->fd);
 222     mp->fd = -1;
 223     return rc;
 224   }
 225
 226   /* Connect to the remote mp. */
 227   return (sockunion_connect(mp->fd, &mp->su_peer, htons(PIM_MSDP_TCP_PORT), 0));
 228 }
 229