gio/gnetworkmonitornetlink.c

   1 /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright 2011 Red Hat, Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include "config.h"
  20
  21 #include <errno.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24
  25 #include "gnetworkmonitornetlink.h"
  26 #include "gcredentials.h"
  27 #include "ginetaddressmask.h"
  28 #include "ginitable.h"
  29 #include "giomodule-priv.h"
  30 #include "glibintl.h"
  31 #include "glib/gstdio.h"
  32 #include "gnetworkingprivate.h"
  33 #include "gnetworkmonitor.h"
  34 #include "gsocket.h"
  35 #include "gunixcredentialsmessage.h"
  36
  37 /* must come at the end to pick system includes from
  38  * gnetworkingprivate.h */
  39 #include <linux/netlink.h>
  40 #include <linux/rtnetlink.h>
  41
  42 static void g_network_monitor_netlink_iface_init (GNetworkMonitorInterface *iface);
  43 static void g_network_monitor_netlink_initable_iface_init (GInitableIface *iface);
  44
  45 struct _GNetworkMonitorNetlinkPrivate
  46 {
  47   GSocket *sock;
  48   GSource *source, *dump_source;
  49
  50   GPtrArray *dump_networks;
  51 };
  52
  53 static gboolean read_netlink_messages (GSocket             *socket,
  54                                        GIOCondition         condition,
  55                                        gpointer             user_data);
  56 static gboolean request_dump (GNetworkMonitorNetlink  *nl,
  57                               GError                 **error);
  58
  59 #define g_network_monitor_netlink_get_type _g_network_monitor_netlink_get_type
  60 G_DEFINE_TYPE_WITH_CODE (GNetworkMonitorNetlink, g_network_monitor_netlink, G_TYPE_NETWORK_MONITOR_BASE,
  61                          G_ADD_PRIVATE (GNetworkMonitorNetlink)
  62                          G_IMPLEMENT_INTERFACE (G_TYPE_NETWORK_MONITOR,
  63                                                 g_network_monitor_netlink_iface_init)
  64                          G_IMPLEMENT_INTERFACE (G_TYPE_INITABLE,
  65                                                 g_network_monitor_netlink_initable_iface_init)
  66                          _g_io_modules_ensure_extension_points_registered ();
  67                          g_io_extension_point_implement (G_NETWORK_MONITOR_EXTENSION_POINT_NAME,
  68                                                          g_define_type_id,
  69                                                          "netlink",
  70                                                          20))
  71
  72 static void
  73 g_network_monitor_netlink_init (GNetworkMonitorNetlink *nl)
  74 {
  75   nl->priv = g_network_monitor_netlink_get_instance_private (nl);
  76 }
  77
  78
  79 static gboolean
  80 g_network_monitor_netlink_initable_init (GInitable     *initable,
  81                                          GCancellable  *cancellable,
  82                                          GError       **error)
  83 {
  84   GNetworkMonitorNetlink *nl = G_NETWORK_MONITOR_NETLINK (initable);
  85   gint sockfd;
  86   struct sockaddr_nl snl;
  87
  88   /* We create the socket the old-school way because sockaddr_netlink
  89    * can't be represented as a GSocketAddress
  90    */
  91   sockfd = g_socket (PF_NETLINK, SOCK_RAW, NETLINK_ROUTE, NULL);
  92   if (sockfd == -1)
  93     {
  94       int errsv = errno;
  95       g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv),
  96                    _("Could not create network monitor: %s"),
  97                    g_strerror (errno));
  98       return FALSE;
  99     }
 100
 101   snl.nl_family = AF_NETLINK;
 102   snl.nl_pid = snl.nl_pad = 0;
 103   snl.nl_groups = RTMGRP_IPV4_ROUTE | RTMGRP_IPV6_ROUTE;
 104   if (bind (sockfd, (struct sockaddr *)&snl, sizeof (snl)) != 0)
 105     {
 106       int errsv = errno;
 107       g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv),
 108                    _("Could not create network monitor: %s"),
 109                    g_strerror (errno));
 110       (void) g_close (sockfd, NULL);
 111       return FALSE;
 112     }
 113
 114   nl->priv->sock = g_socket_new_from_fd (sockfd, error);
 115   if (error)
 116     {
 117       g_prefix_error (error, "%s", _("Could not create network monitor: "));
 118       (void) g_close (sockfd, NULL);
 119       return FALSE;
 120     }
 121
 122   if (!g_socket_set_option (nl->priv->sock, SOL_SOCKET, SO_PASSCRED,
 123                             TRUE, NULL))
 124     {
 125       int errsv = errno;
 126       g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv),
 127                    _("Could not create network monitor: %s"),
 128                    g_strerror (errno));
 129       return FALSE;
 130     }
 131
 132   /* Request the current state */
 133   if (!request_dump (nl, error))
 134     return FALSE;
 135
 136   /* And read responses; since we haven't yet marked the socket
 137    * non-blocking, each call will block until a message is received.
 138    */
 139   while (nl->priv->dump_networks)
 140     {
 141       if (!read_netlink_messages (NULL, G_IO_IN, nl))
 142         break;
 143     }
 144
 145   g_socket_set_blocking (nl->priv->sock, FALSE);
 146   nl->priv->source = g_socket_create_source (nl->priv->sock, G_IO_IN, NULL);
 147   g_source_set_callback (nl->priv->source,
 148                          (GSourceFunc) read_netlink_messages, nl, NULL);
 149   g_source_attach (nl->priv->source,
 150                    g_main_context_get_thread_default ());
 151
 152   return TRUE;
 153 }
 154
 155 static gboolean
 156 request_dump (GNetworkMonitorNetlink  *nl,
 157               GError                 **error)
 158 {
 159   struct nlmsghdr *n;
 160   struct rtgenmsg *gen;
 161   gchar buf[NLMSG_SPACE (sizeof (*gen))];
 162
 163   memset (buf, 0, sizeof (buf));
 164   n = (struct nlmsghdr*) buf;
 165   n->nlmsg_len = NLMSG_LENGTH (sizeof (*gen));
 166   n->nlmsg_type = RTM_GETROUTE;
 167   n->nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
 168   n->nlmsg_pid = 0;
 169   gen = NLMSG_DATA (n);
 170   gen->rtgen_family = AF_UNSPEC;
 171
 172   if (g_socket_send (nl->priv->sock, buf, sizeof (buf),
 173                      NULL, error) < 0)
 174     {
 175       g_prefix_error (error, "%s", _("Could not get network status: "));
 176       return FALSE;
 177     }
 178
 179   nl->priv->dump_networks = g_ptr_array_new_with_free_func (g_object_unref);
 180   return TRUE;
 181 }
 182
 183 static gboolean
 184 timeout_request_dump (gpointer user_data)
 185 {
 186   GNetworkMonitorNetlink *nl = user_data;
 187
 188   g_source_destroy (nl->priv->dump_source);
 189   g_source_unref (nl->priv->dump_source);
 190   nl->priv->dump_source = NULL;
 191
 192   request_dump (nl, NULL);
 193
 194   return FALSE;
 195 }
 196
 197 static void
 198 queue_request_dump (GNetworkMonitorNetlink *nl)
 199 {
 200   if (nl->priv->dump_networks)
 201     return;
 202
 203   if (nl->priv->dump_source)
 204     {
 205       g_source_destroy (nl->priv->dump_source);
 206       g_source_unref (nl->priv->dump_source);
 207     }
 208
 209   nl->priv->dump_source = g_timeout_source_new (1000);
 210   g_source_set_callback (nl->priv->dump_source,
 211                          (GSourceFunc) timeout_request_dump, nl, NULL);
 212   g_source_attach (nl->priv->dump_source,
 213                    g_main_context_get_thread_default ());
 214 }
 215
 216 static void
 217 add_network (GNetworkMonitorNetlink *nl,
 218              GSocketFamily           family,
 219              gint                    dest_len,
 220              guint8                 *dest)
 221 {
 222   GInetAddress *dest_addr;
 223   GInetAddressMask *network;
 224
 225   if (dest)
 226     dest_addr = g_inet_address_new_from_bytes (dest, family);
 227   else
 228     dest_addr = g_inet_address_new_any (family);
 229   network = g_inet_address_mask_new (dest_addr, dest_len, NULL);
 230   g_object_unref (dest_addr);
 231   g_return_if_fail (network != NULL);
 232
 233   if (nl->priv->dump_networks)
 234     g_ptr_array_add (nl->priv->dump_networks, network);
 235   else
 236     {
 237       g_network_monitor_base_add_network (G_NETWORK_MONITOR_BASE (nl), network);
 238       g_object_unref (network);
 239     }
 240 }
 241
 242 static void
 243 remove_network (GNetworkMonitorNetlink *nl,
 244                 GSocketFamily           family,
 245                 gint                    dest_len,
 246                 guint8                 *dest)
 247 {
 248   GInetAddress *dest_addr;
 249   GInetAddressMask *network;
 250
 251   if (dest)
 252     dest_addr = g_inet_address_new_from_bytes (dest, family);
 253   else
 254     dest_addr = g_inet_address_new_any (family);
 255   network = g_inet_address_mask_new (dest_addr, dest_len, NULL);
 256   g_object_unref (dest_addr);
 257   g_return_if_fail (network != NULL);
 258
 259   if (nl->priv->dump_networks)
 260     {
 261       GInetAddressMask **dump_networks = (GInetAddressMask **)nl->priv->dump_networks->pdata;
 262       int i;
 263
 264       for (i = 0; i < nl->priv->dump_networks->len; i++)
 265         {
 266           if (g_inet_address_mask_equal (network, dump_networks[i]))
 267             g_ptr_array_remove_index_fast (nl->priv->dump_networks, i--);
 268         }
 269       g_object_unref (network);
 270     }
 271   else
 272     {
 273       g_network_monitor_base_remove_network (G_NETWORK_MONITOR_BASE (nl), network);
 274       g_object_unref (network);
 275     }
 276 }
 277
 278 static void
 279 finish_dump (GNetworkMonitorNetlink *nl)
 280 {
 281   g_network_monitor_base_set_networks (G_NETWORK_MONITOR_BASE (nl),
 282                                        (GInetAddressMask **)nl->priv->dump_networks->pdata,
 283                                        nl->priv->dump_networks->len);
 284   g_ptr_array_free (nl->priv->dump_networks, TRUE);
 285   nl->priv->dump_networks = NULL;
 286 }
 287
 288 static gboolean
 289 read_netlink_messages (GSocket      *socket,
 290                        GIOCondition  condition,
 291                        gpointer      user_data)
 292 {
 293   GNetworkMonitorNetlink *nl = user_data;
 294   GInputVector iv;
 295   gssize len;
 296   GSocketControlMessage **cmsgs = NULL;
 297   gint num_cmsgs = 0, i, flags;
 298   GError *error = NULL;
 299   GCredentials *creds;
 300   uid_t sender;
 301   struct nlmsghdr *msg;
 302   struct rtmsg *rtmsg;
 303   struct rtattr *attr;
 304   gsize attrlen;
 305   guint8 *dest, *gateway, *oif;
 306   gboolean retval = TRUE;
 307
 308   iv.buffer = NULL;
 309   iv.size = 0;
 310
 311   flags = MSG_PEEK | MSG_TRUNC;
 312   len = g_socket_receive_message (nl->priv->sock, NULL, &iv, 1,
 313                                   NULL, NULL, &flags, NULL, &error);
 314   if (len < 0)
 315     {
 316       g_warning ("Error on netlink socket: %s", error->message);
 317       g_error_free (error);
 318       if (nl->priv->dump_networks)
 319         finish_dump (nl);
 320       return FALSE;
 321     }
 322
 323   iv.buffer = g_malloc (len);
 324   iv.size = len;
 325   len = g_socket_receive_message (nl->priv->sock, NULL, &iv, 1,
 326                                   &cmsgs, &num_cmsgs, NULL, NULL, &error);
 327   if (len < 0)
 328     {
 329       g_warning ("Error on netlink socket: %s", error->message);
 330       g_error_free (error);
 331       if (nl->priv->dump_networks)
 332         finish_dump (nl);
 333       return FALSE;
 334     }
 335
 336   if (num_cmsgs != 1 || !G_IS_UNIX_CREDENTIALS_MESSAGE (cmsgs[0]))
 337     goto done;
 338
 339   creds = g_unix_credentials_message_get_credentials (G_UNIX_CREDENTIALS_MESSAGE (cmsgs[0]));
 340   sender = g_credentials_get_unix_user (creds, NULL);
 341   if (sender != 0)
 342     goto done;
 343
 344   msg = (struct nlmsghdr *) iv.buffer;
 345   for (; len > 0; msg = NLMSG_NEXT (msg, len))
 346     {
 347       if (!NLMSG_OK (msg, (size_t) len))
 348         {
 349           g_warning ("netlink message was truncated; shouldn't happen...");
 350           retval = FALSE;
 351           goto done;
 352         }
 353
 354       switch (msg->nlmsg_type)
 355         {
 356         case RTM_NEWROUTE:
 357         case RTM_DELROUTE:
 358           rtmsg = NLMSG_DATA (msg);
 359
 360           if (rtmsg->rtm_family != AF_INET && rtmsg->rtm_family != AF_INET6)
 361             continue;
 362           if (rtmsg->rtm_type == RTN_UNREACHABLE)
 363             continue;
 364
 365           attrlen = NLMSG_PAYLOAD (msg, sizeof (struct rtmsg));
 366           attr = RTM_RTA (rtmsg);
 367           dest = gateway = oif = NULL;
 368           while (RTA_OK (attr, attrlen))
 369             {
 370               if (attr->rta_type == RTA_DST)
 371                 dest = RTA_DATA (attr);
 372               else if (attr->rta_type == RTA_GATEWAY)
 373                 gateway = RTA_DATA (attr);
 374               else if (attr->rta_type == RTA_OIF)
 375                 oif = RTA_DATA (attr);
 376               attr = RTA_NEXT (attr, attrlen);
 377             }
 378
 379           if (dest || gateway || oif)
 380             {
 381               /* Unless we're processing the results of a dump, ignore
 382                * IPv6 link-local multicast routes, which are added and
 383                * removed all the time for some reason.
 384                */
 385 #define UNALIGNED_IN6_IS_ADDR_MC_LINKLOCAL(a)           \
 386               ((a[0] == 0xff) && ((a[1] & 0xf) == 0x2))
 387
 388               if (!nl->priv->dump_networks &&
 389                   rtmsg->rtm_family == AF_INET6 &&
 390                   rtmsg->rtm_dst_len != 0 &&
 391                   UNALIGNED_IN6_IS_ADDR_MC_LINKLOCAL (dest))
 392                 continue;
 393
 394               if (msg->nlmsg_type == RTM_NEWROUTE)
 395                 add_network (nl, rtmsg->rtm_family, rtmsg->rtm_dst_len, dest);
 396               else
 397                 remove_network (nl, rtmsg->rtm_family, rtmsg->rtm_dst_len, dest);
 398               queue_request_dump (nl);
 399             }
 400           break;
 401
 402         case NLMSG_DONE:
 403           finish_dump (nl);
 404           goto done;
 405
 406         case NLMSG_ERROR:
 407           {
 408             struct nlmsgerr *e = NLMSG_DATA (msg);
 409
 410             g_warning ("netlink error: %s", g_strerror (-e->error));
 411           }
 412           retval = FALSE;
 413           goto done;
 414
 415         default:
 416           g_warning ("unexpected netlink message %d", msg->nlmsg_type);
 417           retval = FALSE;
 418           goto done;
 419         }
 420     }
 421
 422  done:
 423   for (i = 0; i < num_cmsgs; i++)
 424     g_object_unref (cmsgs[i]);
 425   g_free (cmsgs);
 426
 427   g_free (iv.buffer);
 428
 429   if (!retval && nl->priv->dump_networks)
 430     finish_dump (nl);
 431   return retval;
 432 }
 433
 434 static void
 435 g_network_monitor_netlink_finalize (GObject *object)
 436 {
 437   GNetworkMonitorNetlink *nl = G_NETWORK_MONITOR_NETLINK (object);
 438
 439   if (nl->priv->sock)
 440     {
 441       g_socket_close (nl->priv->sock, NULL);
 442       g_object_unref (nl->priv->sock);
 443     }
 444
 445   if (nl->priv->source)
 446     {
 447       g_source_destroy (nl->priv->source);
 448       g_source_unref (nl->priv->source);
 449     }
 450
 451   if (nl->priv->dump_source)
 452     {
 453       g_source_destroy (nl->priv->dump_source);
 454       g_source_unref (nl->priv->dump_source);
 455     }
 456
 457   G_OBJECT_CLASS (g_network_monitor_netlink_parent_class)->finalize (object);
 458 }
 459
 460 static void
 461 g_network_monitor_netlink_class_init (GNetworkMonitorNetlinkClass *nl_class)
 462 {
 463   GObjectClass *gobject_class = G_OBJECT_CLASS (nl_class);
 464
 465   gobject_class->finalize  = g_network_monitor_netlink_finalize;
 466 }
 467
 468 static void
 469 g_network_monitor_netlink_iface_init (GNetworkMonitorInterface *monitor_iface)
 470 {
 471 }
 472
 473 static void
 474 g_network_monitor_netlink_initable_iface_init (GInitableIface *iface)
 475 {
 476   iface->init = g_network_monitor_netlink_initable_init;
 477 }