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
  16  * along with this program; see the file COPYING; if not, write to the
  17  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
  18  * MA 02110-1301 USA
  19  */
  20
  21 #include <zebra.h>
  22
  23 #include <lib/log.h>
  24 #include <lib/network.h>
  25 #include <lib/sockunion.h>
  26 #include <lib/thread.h>
  27 #include <lib/vty.h>
  28
  29 #include "pimd.h"
  30
  31 #include "pim_msdp.h"
  32 #include "pim_msdp_socket.h"
  33
  34 /* increase socket send buffer size */
  35 static void
  36 pim_msdp_update_sock_send_buffer_size (int fd)
  37 {
  38   int size = PIM_MSDP_SOCKET_SNDBUF_SIZE;
  39   int optval;
  40   socklen_t optlen = sizeof(optval);
  41
  42   if (getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &optval, &optlen) < 0) {
  43     zlog_err("getsockopt of SO_SNDBUF failed %s\n", safe_strerror(errno));
  44     return;
  45   }
  46
  47   if (optval < size) {
  48     if (setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &size, sizeof(size)) < 0) {
  49       zlog_err("Couldn't increase send buffer: %s\n", safe_strerror(errno));
  50     }
  51   }
  52 }
  53
  54 /* passive peer socket accept */
  55 static int
  56 pim_msdp_sock_accept(struct thread *thread)
  57 {
  58   union sockunion su;
  59   struct pim_msdp_listener *listener = THREAD_ARG(thread);
  60   int accept_sock;
  61   int msdp_sock;
  62   struct pim_msdp_peer *mp;
  63   char buf[SU_ADDRSTRLEN];
  64
  65   sockunion_init(&su);
  66
  67   /* re-register accept thread */
  68   accept_sock = THREAD_FD(thread);
  69   if (accept_sock < 0) {
  70     zlog_err ("accept_sock is negative value %d", accept_sock);
  71     return -1;
  72   }
  73   listener->thread = thread_add_read(master, pim_msdp_sock_accept,
  74                                      listener, accept_sock);
  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 = thread_add_read(msdp->master, pim_msdp_sock_accept, listener, sock);
 177
 178   msdp->flags |= PIM_MSDPF_LISTENER;
 179   return 0;
 180 }
 181
 182 /* active peer socket setup */
 183 int
 184 pim_msdp_sock_connect(struct pim_msdp_peer *mp)
 185 {
 186   int rc;
 187
 188   if (PIM_DEBUG_MSDP_INTERNAL) {
 189     zlog_debug("MSDP peer %s attempt connect%s", mp->key_str, mp->fd<0?"":"(dup)");
 190   }
 191
 192   /* if we have an existing connection we need to kill that one
 193    * with this one */
 194   if (mp->fd >= 0) {
 195     if (PIM_DEBUG_MSDP_EVENTS) {
 196       zlog_err("msdp duplicate connect to %s nuke old connection", mp->key_str);
 197     }
 198     pim_msdp_peer_stop_tcp_conn(mp, false /* chg_state */);
 199   }
 200
 201   /* Make socket for the peer. */
 202   mp->fd = sockunion_socket(&mp->su_peer);
 203   if (mp->fd < 0) {
 204     zlog_err ("pim_msdp_socket socket failure: %s", safe_strerror (errno));
 205     return -1;
 206   }
 207
 208   set_nonblocking(mp->fd);
 209
 210   /* Set socket send buffer size */
 211   pim_msdp_update_sock_send_buffer_size(mp->fd);
 212   sockopt_reuseaddr(mp->fd);
 213   sockopt_reuseport(mp->fd);
 214
 215   /* source bind */
 216   rc = sockunion_bind(mp->fd, &mp->su_local, 0, &mp->su_local);
 217   if (rc < 0) {
 218     zlog_err ("pim_msdp_socket connect bind failure: %s", safe_strerror (errno));
 219     close(mp->fd);
 220     mp->fd = -1;
 221     return rc;
 222   }
 223
 224   /* Connect to the remote mp. */
 225   return (sockunion_connect(mp->fd, &mp->su_peer, htons(PIM_MSDP_TCP_PORT), 0));
 226 }
 227