net/batman-adv/gateway_client.c

   1 /*
   2  * Copyright (C) 2009-2011 B.A.T.M.A.N. contributors:
   3  *
   4  * Marek Lindner
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of version 2 of the GNU General Public
   8  * License as published by the Free Software Foundation.
   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; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  * 02110-1301, USA
  19  *
  20  */
  21
  22 #include "main.h"
  23 #include "gateway_client.h"
  24 #include "gateway_common.h"
  25 #include "hard-interface.h"
  26 #include <linux/ip.h>
  27 #include <linux/ipv6.h>
  28 #include <linux/udp.h>
  29 #include <linux/if_vlan.h>
  30
  31 static void gw_node_free_rcu(struct rcu_head *rcu)
  32 {
  33         struct gw_node *gw_node;
  34
  35         gw_node = container_of(rcu, struct gw_node, rcu);
  36         kfree(gw_node);
  37 }
  38
  39 static void gw_node_free_ref(struct gw_node *gw_node)
  40 {
  41         if (atomic_dec_and_test(&gw_node->refcount))
  42                 call_rcu(&gw_node->rcu, gw_node_free_rcu);
  43 }
  44
  45 void *gw_get_selected(struct bat_priv *bat_priv)
  46 {
  47         struct gw_node *curr_gateway_tmp;
  48         struct orig_node *orig_node = NULL;
  49
  50         rcu_read_lock();
  51         curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
  52         if (!curr_gateway_tmp)
  53                 goto out;
  54
  55         orig_node = curr_gateway_tmp->orig_node;
  56
  57         if (orig_node)
  58                 kref_get(&orig_node->refcount);
  59
  60 out:
  61         rcu_read_unlock();
  62         return orig_node;
  63 }
  64
  65 void gw_deselect(struct bat_priv *bat_priv)
  66 {
  67         struct gw_node *gw_node;
  68
  69         spin_lock_bh(&bat_priv->gw_list_lock);
  70         gw_node = rcu_dereference(bat_priv->curr_gw);
  71         rcu_assign_pointer(bat_priv->curr_gw, NULL);
  72         spin_unlock_bh(&bat_priv->gw_list_lock);
  73
  74         if (gw_node)
  75                 gw_node_free_ref(gw_node);
  76 }
  77
  78 static void gw_select(struct bat_priv *bat_priv, struct gw_node *new_gw_node)
  79 {
  80         struct gw_node *curr_gw_node;
  81
  82         if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
  83                 new_gw_node = NULL;
  84
  85         spin_lock_bh(&bat_priv->gw_list_lock);
  86         curr_gw_node = rcu_dereference(bat_priv->curr_gw);
  87         rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
  88         spin_unlock_bh(&bat_priv->gw_list_lock);
  89
  90         if (curr_gw_node)
  91                 gw_node_free_ref(curr_gw_node);
  92 }
  93
  94 void gw_election(struct bat_priv *bat_priv)
  95 {
  96         struct hlist_node *node;
  97         struct gw_node *gw_node, *curr_gw, *curr_gw_tmp = NULL;
  98         uint8_t max_tq = 0;
  99         uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
 100         int down, up;
 101
 102         /**
 103          * The batman daemon checks here if we already passed a full originator
 104          * cycle in order to make sure we don't choose the first gateway we
 105          * hear about. This check is based on the daemon's uptime which we
 106          * don't have.
 107          **/
 108         if (atomic_read(&bat_priv->gw_mode) != GW_MODE_CLIENT)
 109                 return;
 110
 111         rcu_read_lock();
 112         curr_gw = rcu_dereference(bat_priv->curr_gw);
 113         if (curr_gw) {
 114                 rcu_read_unlock();
 115                 return;
 116         }
 117
 118         if (hlist_empty(&bat_priv->gw_list)) {
 119
 120                 if (curr_gw) {
 121                         rcu_read_unlock();
 122                         bat_dbg(DBG_BATMAN, bat_priv,
 123                                 "Removing selected gateway - "
 124                                 "no gateway in range\n");
 125                         gw_deselect(bat_priv);
 126                 } else
 127                         rcu_read_unlock();
 128
 129                 return;
 130         }
 131
 132         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 133                 if (!gw_node->orig_node->router)
 134                         continue;
 135
 136                 if (gw_node->deleted)
 137                         continue;
 138
 139                 switch (atomic_read(&bat_priv->gw_sel_class)) {
 140                 case 1: /* fast connection */
 141                         gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags,
 142                                              &down, &up);
 143
 144                         tmp_gw_factor = (gw_node->orig_node->router->tq_avg *
 145                                          gw_node->orig_node->router->tq_avg *
 146                                          down * 100 * 100) /
 147                                          (TQ_LOCAL_WINDOW_SIZE *
 148                                          TQ_LOCAL_WINDOW_SIZE * 64);
 149
 150                         if ((tmp_gw_factor > max_gw_factor) ||
 151                             ((tmp_gw_factor == max_gw_factor) &&
 152                              (gw_node->orig_node->router->tq_avg > max_tq)))
 153                                 curr_gw_tmp = gw_node;
 154                         break;
 155
 156                 default: /**
 157                           * 2:  stable connection (use best statistic)
 158                           * 3:  fast-switch (use best statistic but change as
 159                           *     soon as a better gateway appears)
 160                           * XX: late-switch (use best statistic but change as
 161                           *     soon as a better gateway appears which has
 162                           *     $routing_class more tq points)
 163                           **/
 164                         if (gw_node->orig_node->router->tq_avg > max_tq)
 165                                 curr_gw_tmp = gw_node;
 166                         break;
 167                 }
 168
 169                 if (gw_node->orig_node->router->tq_avg > max_tq)
 170                         max_tq = gw_node->orig_node->router->tq_avg;
 171
 172                 if (tmp_gw_factor > max_gw_factor)
 173                         max_gw_factor = tmp_gw_factor;
 174         }
 175
 176         if (curr_gw != curr_gw_tmp) {
 177                 if ((curr_gw) && (!curr_gw_tmp))
 178                         bat_dbg(DBG_BATMAN, bat_priv,
 179                                 "Removing selected gateway - "
 180                                 "no gateway in range\n");
 181                 else if ((!curr_gw) && (curr_gw_tmp))
 182                         bat_dbg(DBG_BATMAN, bat_priv,
 183                                 "Adding route to gateway %pM "
 184                                 "(gw_flags: %i, tq: %i)\n",
 185                                 curr_gw_tmp->orig_node->orig,
 186                                 curr_gw_tmp->orig_node->gw_flags,
 187                                 curr_gw_tmp->orig_node->router->tq_avg);
 188                 else
 189                         bat_dbg(DBG_BATMAN, bat_priv,
 190                                 "Changing route to gateway %pM "
 191                                 "(gw_flags: %i, tq: %i)\n",
 192                                 curr_gw_tmp->orig_node->orig,
 193                                 curr_gw_tmp->orig_node->gw_flags,
 194                                 curr_gw_tmp->orig_node->router->tq_avg);
 195
 196                 gw_select(bat_priv, curr_gw_tmp);
 197         }
 198
 199         rcu_read_unlock();
 200 }
 201
 202 void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
 203 {
 204         struct gw_node *curr_gateway_tmp;
 205         uint8_t gw_tq_avg, orig_tq_avg;
 206
 207         rcu_read_lock();
 208         curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
 209         if (!curr_gateway_tmp)
 210                 goto out_rcu;
 211
 212         if (!curr_gateway_tmp->orig_node)
 213                 goto deselect_rcu;
 214
 215         if (!curr_gateway_tmp->orig_node->router)
 216                 goto deselect_rcu;
 217
 218         /* this node already is the gateway */
 219         if (curr_gateway_tmp->orig_node == orig_node)
 220                 goto out_rcu;
 221
 222         if (!orig_node->router)
 223                 goto out_rcu;
 224
 225         gw_tq_avg = curr_gateway_tmp->orig_node->router->tq_avg;
 226         rcu_read_unlock();
 227
 228         orig_tq_avg = orig_node->router->tq_avg;
 229
 230         /* the TQ value has to be better */
 231         if (orig_tq_avg < gw_tq_avg)
 232                 goto out;
 233
 234         /**
 235          * if the routing class is greater than 3 the value tells us how much
 236          * greater the TQ value of the new gateway must be
 237          **/
 238         if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
 239             (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
 240                 goto out;
 241
 242         bat_dbg(DBG_BATMAN, bat_priv,
 243                 "Restarting gateway selection: better gateway found (tq curr: "
 244                 "%i, tq new: %i)\n",
 245                 gw_tq_avg, orig_tq_avg);
 246         goto deselect;
 247
 248 out_rcu:
 249         rcu_read_unlock();
 250         goto out;
 251 deselect_rcu:
 252         rcu_read_unlock();
 253 deselect:
 254         gw_deselect(bat_priv);
 255 out:
 256         return;
 257 }
 258
 259 static void gw_node_add(struct bat_priv *bat_priv,
 260                         struct orig_node *orig_node, uint8_t new_gwflags)
 261 {
 262         struct gw_node *gw_node;
 263         int down, up;
 264
 265         gw_node = kmalloc(sizeof(struct gw_node), GFP_ATOMIC);
 266         if (!gw_node)
 267                 return;
 268
 269         memset(gw_node, 0, sizeof(struct gw_node));
 270         INIT_HLIST_NODE(&gw_node->list);
 271         gw_node->orig_node = orig_node;
 272         atomic_set(&gw_node->refcount, 1);
 273
 274         spin_lock_bh(&bat_priv->gw_list_lock);
 275         hlist_add_head_rcu(&gw_node->list, &bat_priv->gw_list);
 276         spin_unlock_bh(&bat_priv->gw_list_lock);
 277
 278         gw_bandwidth_to_kbit(new_gwflags, &down, &up);
 279         bat_dbg(DBG_BATMAN, bat_priv,
 280                 "Found new gateway %pM -> gw_class: %i - %i%s/%i%s\n",
 281                 orig_node->orig, new_gwflags,
 282                 (down > 2048 ? down / 1024 : down),
 283                 (down > 2048 ? "MBit" : "KBit"),
 284                 (up > 2048 ? up / 1024 : up),
 285                 (up > 2048 ? "MBit" : "KBit"));
 286 }
 287
 288 void gw_node_update(struct bat_priv *bat_priv,
 289                     struct orig_node *orig_node, uint8_t new_gwflags)
 290 {
 291         struct hlist_node *node;
 292         struct gw_node *gw_node;
 293
 294         rcu_read_lock();
 295         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 296                 if (gw_node->orig_node != orig_node)
 297                         continue;
 298
 299                 bat_dbg(DBG_BATMAN, bat_priv,
 300                         "Gateway class of originator %pM changed from "
 301                         "%i to %i\n",
 302                         orig_node->orig, gw_node->orig_node->gw_flags,
 303                         new_gwflags);
 304
 305                 gw_node->deleted = 0;
 306
 307                 if (new_gwflags == 0) {
 308                         gw_node->deleted = jiffies;
 309                         bat_dbg(DBG_BATMAN, bat_priv,
 310                                 "Gateway %pM removed from gateway list\n",
 311                                 orig_node->orig);
 312
 313                         if (gw_node == rcu_dereference(bat_priv->curr_gw)) {
 314                                 rcu_read_unlock();
 315                                 gw_deselect(bat_priv);
 316                                 return;
 317                         }
 318                 }
 319
 320                 rcu_read_unlock();
 321                 return;
 322         }
 323         rcu_read_unlock();
 324
 325         if (new_gwflags == 0)
 326                 return;
 327
 328         gw_node_add(bat_priv, orig_node, new_gwflags);
 329 }
 330
 331 void gw_node_delete(struct bat_priv *bat_priv, struct orig_node *orig_node)
 332 {
 333         return gw_node_update(bat_priv, orig_node, 0);
 334 }
 335
 336 void gw_node_purge(struct bat_priv *bat_priv)
 337 {
 338         struct gw_node *gw_node;
 339         struct hlist_node *node, *node_tmp;
 340         unsigned long timeout = 2 * PURGE_TIMEOUT * HZ;
 341
 342         spin_lock_bh(&bat_priv->gw_list_lock);
 343
 344         hlist_for_each_entry_safe(gw_node, node, node_tmp,
 345                                   &bat_priv->gw_list, list) {
 346                 if (((!gw_node->deleted) ||
 347                      (time_before(jiffies, gw_node->deleted + timeout))) &&
 348                     atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE)
 349                         continue;
 350
 351                 if (rcu_dereference(bat_priv->curr_gw) == gw_node)
 352                         gw_deselect(bat_priv);
 353
 354                 hlist_del_rcu(&gw_node->list);
 355                 gw_node_free_ref(gw_node);
 356         }
 357
 358
 359         spin_unlock_bh(&bat_priv->gw_list_lock);
 360 }
 361
 362 static int _write_buffer_text(struct bat_priv *bat_priv,
 363                               struct seq_file *seq, struct gw_node *gw_node)
 364 {
 365         struct gw_node *curr_gw;
 366         int down, up, ret;
 367
 368         gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);
 369
 370         rcu_read_lock();
 371         curr_gw = rcu_dereference(bat_priv->curr_gw);
 372
 373         ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
 374                        (curr_gw == gw_node ? "=>" : "  "),
 375                        gw_node->orig_node->orig,
 376                        gw_node->orig_node->router->tq_avg,
 377                        gw_node->orig_node->router->addr,
 378                        gw_node->orig_node->router->if_incoming->net_dev->name,
 379                        gw_node->orig_node->gw_flags,
 380                        (down > 2048 ? down / 1024 : down),
 381                        (down > 2048 ? "MBit" : "KBit"),
 382                        (up > 2048 ? up / 1024 : up),
 383                        (up > 2048 ? "MBit" : "KBit"));
 384
 385         rcu_read_unlock();
 386         return ret;
 387 }
 388
 389 int gw_client_seq_print_text(struct seq_file *seq, void *offset)
 390 {
 391         struct net_device *net_dev = (struct net_device *)seq->private;
 392         struct bat_priv *bat_priv = netdev_priv(net_dev);
 393         struct gw_node *gw_node;
 394         struct hlist_node *node;
 395         int gw_count = 0;
 396
 397         if (!bat_priv->primary_if) {
 398
 399                 return seq_printf(seq, "BATMAN mesh %s disabled - please "
 400                                   "specify interfaces to enable it\n",
 401                                   net_dev->name);
 402         }
 403
 404         if (bat_priv->primary_if->if_status != IF_ACTIVE) {
 405
 406                 return seq_printf(seq, "BATMAN mesh %s disabled - "
 407                                        "primary interface not active\n",
 408                                        net_dev->name);
 409         }
 410
 411         seq_printf(seq, "      %-12s (%s/%i) %17s [%10s]: gw_class ... "
 412                    "[B.A.T.M.A.N. adv %s%s, MainIF/MAC: %s/%pM (%s)]\n",
 413                    "Gateway", "#", TQ_MAX_VALUE, "Nexthop",
 414                    "outgoingIF", SOURCE_VERSION, REVISION_VERSION_STR,
 415                    bat_priv->primary_if->net_dev->name,
 416                    bat_priv->primary_if->net_dev->dev_addr, net_dev->name);
 417
 418         rcu_read_lock();
 419         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 420                 if (gw_node->deleted)
 421                         continue;
 422
 423                 if (!gw_node->orig_node->router)
 424                         continue;
 425
 426                 _write_buffer_text(bat_priv, seq, gw_node);
 427                 gw_count++;
 428         }
 429         rcu_read_unlock();
 430
 431         if (gw_count == 0)
 432                 seq_printf(seq, "No gateways in range ...\n");
 433
 434         return 0;
 435 }
 436
 437 int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb)
 438 {
 439         struct ethhdr *ethhdr;
 440         struct iphdr *iphdr;
 441         struct ipv6hdr *ipv6hdr;
 442         struct udphdr *udphdr;
 443         unsigned int header_len = 0;
 444
 445         if (atomic_read(&bat_priv->gw_mode) == GW_MODE_OFF)
 446                 return 0;
 447
 448         /* check for ethernet header */
 449         if (!pskb_may_pull(skb, header_len + ETH_HLEN))
 450                 return 0;
 451         ethhdr = (struct ethhdr *)skb->data;
 452         header_len += ETH_HLEN;
 453
 454         /* check for initial vlan header */
 455         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
 456                 if (!pskb_may_pull(skb, header_len + VLAN_HLEN))
 457                         return 0;
 458                 ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
 459                 header_len += VLAN_HLEN;
 460         }
 461
 462         /* check for ip header */
 463         switch (ntohs(ethhdr->h_proto)) {
 464         case ETH_P_IP:
 465                 if (!pskb_may_pull(skb, header_len + sizeof(struct iphdr)))
 466                         return 0;
 467                 iphdr = (struct iphdr *)(skb->data + header_len);
 468                 header_len += iphdr->ihl * 4;
 469
 470                 /* check for udp header */
 471                 if (iphdr->protocol != IPPROTO_UDP)
 472                         return 0;
 473
 474                 break;
 475         case ETH_P_IPV6:
 476                 if (!pskb_may_pull(skb, header_len + sizeof(struct ipv6hdr)))
 477                         return 0;
 478                 ipv6hdr = (struct ipv6hdr *)(skb->data + header_len);
 479                 header_len += sizeof(struct ipv6hdr);
 480
 481                 /* check for udp header */
 482                 if (ipv6hdr->nexthdr != IPPROTO_UDP)
 483                         return 0;
 484
 485                 break;
 486         default:
 487                 return 0;
 488         }
 489
 490         if (!pskb_may_pull(skb, header_len + sizeof(struct udphdr)))
 491                 return 0;
 492         udphdr = (struct udphdr *)(skb->data + header_len);
 493         header_len += sizeof(struct udphdr);
 494
 495         /* check for bootp port */
 496         if ((ntohs(ethhdr->h_proto) == ETH_P_IP) &&
 497              (ntohs(udphdr->dest) != 67))
 498                 return 0;
 499
 500         if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
 501             (ntohs(udphdr->dest) != 547))
 502                 return 0;
 503
 504         if (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER)
 505                 return -1;
 506
 507         rcu_read_lock();
 508         if (!rcu_dereference(bat_priv->curr_gw)) {
 509                 rcu_read_unlock();
 510                 return 0;
 511         }
 512         rcu_read_unlock();
 513
 514         return 1;
 515 }