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 "originator.h"
  27 #include <linux/ip.h>
  28 #include <linux/ipv6.h>
  29 #include <linux/udp.h>
  30 #include <linux/if_vlan.h>
  31
  32 static void gw_node_free_rcu(struct rcu_head *rcu)
  33 {
  34         struct gw_node *gw_node;
  35
  36         gw_node = container_of(rcu, struct gw_node, rcu);
  37         kfree(gw_node);
  38 }
  39
  40 static void gw_node_free_ref(struct gw_node *gw_node)
  41 {
  42         if (atomic_dec_and_test(&gw_node->refcount))
  43                 call_rcu(&gw_node->rcu, gw_node_free_rcu);
  44 }
  45
  46 struct orig_node *gw_get_selected(struct bat_priv *bat_priv)
  47 {
  48         struct gw_node *curr_gateway_tmp;
  49         struct orig_node *orig_node = NULL;
  50
  51         rcu_read_lock();
  52         curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
  53         if (!curr_gateway_tmp)
  54                 goto out;
  55
  56         orig_node = curr_gateway_tmp->orig_node;
  57         if (!orig_node)
  58                 goto out;
  59
  60         if (!atomic_inc_not_zero(&orig_node->refcount))
  61                 orig_node = NULL;
  62
  63 out:
  64         rcu_read_unlock();
  65         return orig_node;
  66 }
  67
  68 void gw_deselect(struct bat_priv *bat_priv)
  69 {
  70         struct gw_node *gw_node;
  71
  72         spin_lock_bh(&bat_priv->gw_list_lock);
  73         gw_node = rcu_dereference(bat_priv->curr_gw);
  74         rcu_assign_pointer(bat_priv->curr_gw, NULL);
  75         spin_unlock_bh(&bat_priv->gw_list_lock);
  76
  77         if (gw_node)
  78                 gw_node_free_ref(gw_node);
  79 }
  80
  81 static void gw_select(struct bat_priv *bat_priv, struct gw_node *new_gw_node)
  82 {
  83         struct gw_node *curr_gw_node;
  84
  85         if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
  86                 new_gw_node = NULL;
  87
  88         spin_lock_bh(&bat_priv->gw_list_lock);
  89         curr_gw_node = rcu_dereference(bat_priv->curr_gw);
  90         rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
  91         spin_unlock_bh(&bat_priv->gw_list_lock);
  92
  93         if (curr_gw_node)
  94                 gw_node_free_ref(curr_gw_node);
  95 }
  96
  97 void gw_election(struct bat_priv *bat_priv)
  98 {
  99         struct hlist_node *node;
 100         struct gw_node *gw_node, *curr_gw, *curr_gw_tmp = NULL;
 101         uint8_t max_tq = 0;
 102         uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
 103         int down, up;
 104
 105         /**
 106          * The batman daemon checks here if we already passed a full originator
 107          * cycle in order to make sure we don't choose the first gateway we
 108          * hear about. This check is based on the daemon's uptime which we
 109          * don't have.
 110          **/
 111         if (atomic_read(&bat_priv->gw_mode) != GW_MODE_CLIENT)
 112                 return;
 113
 114         rcu_read_lock();
 115         curr_gw = rcu_dereference(bat_priv->curr_gw);
 116         if (curr_gw) {
 117                 rcu_read_unlock();
 118                 return;
 119         }
 120
 121         if (hlist_empty(&bat_priv->gw_list)) {
 122
 123                 if (curr_gw) {
 124                         rcu_read_unlock();
 125                         bat_dbg(DBG_BATMAN, bat_priv,
 126                                 "Removing selected gateway - "
 127                                 "no gateway in range\n");
 128                         gw_deselect(bat_priv);
 129                 } else
 130                         rcu_read_unlock();
 131
 132                 return;
 133         }
 134
 135         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 136                 if (!gw_node->orig_node->router)
 137                         continue;
 138
 139                 if (gw_node->deleted)
 140                         continue;
 141
 142                 switch (atomic_read(&bat_priv->gw_sel_class)) {
 143                 case 1: /* fast connection */
 144                         gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags,
 145                                              &down, &up);
 146
 147                         tmp_gw_factor = (gw_node->orig_node->router->tq_avg *
 148                                          gw_node->orig_node->router->tq_avg *
 149                                          down * 100 * 100) /
 150                                          (TQ_LOCAL_WINDOW_SIZE *
 151                                          TQ_LOCAL_WINDOW_SIZE * 64);
 152
 153                         if ((tmp_gw_factor > max_gw_factor) ||
 154                             ((tmp_gw_factor == max_gw_factor) &&
 155                              (gw_node->orig_node->router->tq_avg > max_tq)))
 156                                 curr_gw_tmp = gw_node;
 157                         break;
 158
 159                 default: /**
 160                           * 2:  stable connection (use best statistic)
 161                           * 3:  fast-switch (use best statistic but change as
 162                           *     soon as a better gateway appears)
 163                           * XX: late-switch (use best statistic but change as
 164                           *     soon as a better gateway appears which has
 165                           *     $routing_class more tq points)
 166                           **/
 167                         if (gw_node->orig_node->router->tq_avg > max_tq)
 168                                 curr_gw_tmp = gw_node;
 169                         break;
 170                 }
 171
 172                 if (gw_node->orig_node->router->tq_avg > max_tq)
 173                         max_tq = gw_node->orig_node->router->tq_avg;
 174
 175                 if (tmp_gw_factor > max_gw_factor)
 176                         max_gw_factor = tmp_gw_factor;
 177         }
 178
 179         if (curr_gw != curr_gw_tmp) {
 180                 if ((curr_gw) && (!curr_gw_tmp))
 181                         bat_dbg(DBG_BATMAN, bat_priv,
 182                                 "Removing selected gateway - "
 183                                 "no gateway in range\n");
 184                 else if ((!curr_gw) && (curr_gw_tmp))
 185                         bat_dbg(DBG_BATMAN, bat_priv,
 186                                 "Adding route to gateway %pM "
 187                                 "(gw_flags: %i, tq: %i)\n",
 188                                 curr_gw_tmp->orig_node->orig,
 189                                 curr_gw_tmp->orig_node->gw_flags,
 190                                 curr_gw_tmp->orig_node->router->tq_avg);
 191                 else
 192                         bat_dbg(DBG_BATMAN, bat_priv,
 193                                 "Changing route to gateway %pM "
 194                                 "(gw_flags: %i, tq: %i)\n",
 195                                 curr_gw_tmp->orig_node->orig,
 196                                 curr_gw_tmp->orig_node->gw_flags,
 197                                 curr_gw_tmp->orig_node->router->tq_avg);
 198
 199                 gw_select(bat_priv, curr_gw_tmp);
 200         }
 201
 202         rcu_read_unlock();
 203 }
 204
 205 void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
 206 {
 207         struct orig_node *curr_gw_orig;
 208         uint8_t gw_tq_avg, orig_tq_avg;
 209
 210         curr_gw_orig = gw_get_selected(bat_priv);
 211         if (!curr_gw_orig)
 212                 goto deselect;
 213
 214         rcu_read_lock();
 215         if (!curr_gw_orig->router)
 216                 goto deselect_rcu;
 217
 218         /* this node already is the gateway */
 219         if (curr_gw_orig == orig_node)
 220                 goto out_rcu;
 221
 222         if (!orig_node->router)
 223                 goto out_rcu;
 224
 225         gw_tq_avg = curr_gw_orig->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         if (curr_gw_orig)
 257                 orig_node_free_ref(curr_gw_orig);
 258
 259         return;
 260 }
 261
 262 static void gw_node_add(struct bat_priv *bat_priv,
 263                         struct orig_node *orig_node, uint8_t new_gwflags)
 264 {
 265         struct gw_node *gw_node;
 266         int down, up;
 267
 268         gw_node = kmalloc(sizeof(struct gw_node), GFP_ATOMIC);
 269         if (!gw_node)
 270                 return;
 271
 272         memset(gw_node, 0, sizeof(struct gw_node));
 273         INIT_HLIST_NODE(&gw_node->list);
 274         gw_node->orig_node = orig_node;
 275         atomic_set(&gw_node->refcount, 1);
 276
 277         spin_lock_bh(&bat_priv->gw_list_lock);
 278         hlist_add_head_rcu(&gw_node->list, &bat_priv->gw_list);
 279         spin_unlock_bh(&bat_priv->gw_list_lock);
 280
 281         gw_bandwidth_to_kbit(new_gwflags, &down, &up);
 282         bat_dbg(DBG_BATMAN, bat_priv,
 283                 "Found new gateway %pM -> gw_class: %i - %i%s/%i%s\n",
 284                 orig_node->orig, new_gwflags,
 285                 (down > 2048 ? down / 1024 : down),
 286                 (down > 2048 ? "MBit" : "KBit"),
 287                 (up > 2048 ? up / 1024 : up),
 288                 (up > 2048 ? "MBit" : "KBit"));
 289 }
 290
 291 void gw_node_update(struct bat_priv *bat_priv,
 292                     struct orig_node *orig_node, uint8_t new_gwflags)
 293 {
 294         struct hlist_node *node;
 295         struct gw_node *gw_node;
 296
 297         rcu_read_lock();
 298         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 299                 if (gw_node->orig_node != orig_node)
 300                         continue;
 301
 302                 bat_dbg(DBG_BATMAN, bat_priv,
 303                         "Gateway class of originator %pM changed from "
 304                         "%i to %i\n",
 305                         orig_node->orig, gw_node->orig_node->gw_flags,
 306                         new_gwflags);
 307
 308                 gw_node->deleted = 0;
 309
 310                 if (new_gwflags == 0) {
 311                         gw_node->deleted = jiffies;
 312                         bat_dbg(DBG_BATMAN, bat_priv,
 313                                 "Gateway %pM removed from gateway list\n",
 314                                 orig_node->orig);
 315
 316                         if (gw_node == rcu_dereference(bat_priv->curr_gw)) {
 317                                 rcu_read_unlock();
 318                                 gw_deselect(bat_priv);
 319                                 return;
 320                         }
 321                 }
 322
 323                 rcu_read_unlock();
 324                 return;
 325         }
 326         rcu_read_unlock();
 327
 328         if (new_gwflags == 0)
 329                 return;
 330
 331         gw_node_add(bat_priv, orig_node, new_gwflags);
 332 }
 333
 334 void gw_node_delete(struct bat_priv *bat_priv, struct orig_node *orig_node)
 335 {
 336         return gw_node_update(bat_priv, orig_node, 0);
 337 }
 338
 339 void gw_node_purge(struct bat_priv *bat_priv)
 340 {
 341         struct gw_node *gw_node;
 342         struct hlist_node *node, *node_tmp;
 343         unsigned long timeout = 2 * PURGE_TIMEOUT * HZ;
 344
 345         spin_lock_bh(&bat_priv->gw_list_lock);
 346
 347         hlist_for_each_entry_safe(gw_node, node, node_tmp,
 348                                   &bat_priv->gw_list, list) {
 349                 if (((!gw_node->deleted) ||
 350                      (time_before(jiffies, gw_node->deleted + timeout))) &&
 351                     atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE)
 352                         continue;
 353
 354                 if (rcu_dereference(bat_priv->curr_gw) == gw_node)
 355                         gw_deselect(bat_priv);
 356
 357                 hlist_del_rcu(&gw_node->list);
 358                 gw_node_free_ref(gw_node);
 359         }
 360
 361
 362         spin_unlock_bh(&bat_priv->gw_list_lock);
 363 }
 364
 365 static int _write_buffer_text(struct bat_priv *bat_priv,
 366                               struct seq_file *seq, struct gw_node *gw_node)
 367 {
 368         struct gw_node *curr_gw;
 369         int down, up, ret;
 370
 371         gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);
 372
 373         rcu_read_lock();
 374         curr_gw = rcu_dereference(bat_priv->curr_gw);
 375
 376         ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
 377                        (curr_gw == gw_node ? "=>" : "  "),
 378                        gw_node->orig_node->orig,
 379                        gw_node->orig_node->router->tq_avg,
 380                        gw_node->orig_node->router->addr,
 381                        gw_node->orig_node->router->if_incoming->net_dev->name,
 382                        gw_node->orig_node->gw_flags,
 383                        (down > 2048 ? down / 1024 : down),
 384                        (down > 2048 ? "MBit" : "KBit"),
 385                        (up > 2048 ? up / 1024 : up),
 386                        (up > 2048 ? "MBit" : "KBit"));
 387
 388         rcu_read_unlock();
 389         return ret;
 390 }
 391
 392 int gw_client_seq_print_text(struct seq_file *seq, void *offset)
 393 {
 394         struct net_device *net_dev = (struct net_device *)seq->private;
 395         struct bat_priv *bat_priv = netdev_priv(net_dev);
 396         struct gw_node *gw_node;
 397         struct hlist_node *node;
 398         int gw_count = 0;
 399
 400         if (!bat_priv->primary_if) {
 401
 402                 return seq_printf(seq, "BATMAN mesh %s disabled - please "
 403                                   "specify interfaces to enable it\n",
 404                                   net_dev->name);
 405         }
 406
 407         if (bat_priv->primary_if->if_status != IF_ACTIVE) {
 408
 409                 return seq_printf(seq, "BATMAN mesh %s disabled - "
 410                                        "primary interface not active\n",
 411                                        net_dev->name);
 412         }
 413
 414         seq_printf(seq, "      %-12s (%s/%i) %17s [%10s]: gw_class ... "
 415                    "[B.A.T.M.A.N. adv %s%s, MainIF/MAC: %s/%pM (%s)]\n",
 416                    "Gateway", "#", TQ_MAX_VALUE, "Nexthop",
 417                    "outgoingIF", SOURCE_VERSION, REVISION_VERSION_STR,
 418                    bat_priv->primary_if->net_dev->name,
 419                    bat_priv->primary_if->net_dev->dev_addr, net_dev->name);
 420
 421         rcu_read_lock();
 422         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 423                 if (gw_node->deleted)
 424                         continue;
 425
 426                 if (!gw_node->orig_node->router)
 427                         continue;
 428
 429                 _write_buffer_text(bat_priv, seq, gw_node);
 430                 gw_count++;
 431         }
 432         rcu_read_unlock();
 433
 434         if (gw_count == 0)
 435                 seq_printf(seq, "No gateways in range ...\n");
 436
 437         return 0;
 438 }
 439
 440 int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb)
 441 {
 442         struct ethhdr *ethhdr;
 443         struct iphdr *iphdr;
 444         struct ipv6hdr *ipv6hdr;
 445         struct udphdr *udphdr;
 446         unsigned int header_len = 0;
 447
 448         if (atomic_read(&bat_priv->gw_mode) == GW_MODE_OFF)
 449                 return 0;
 450
 451         /* check for ethernet header */
 452         if (!pskb_may_pull(skb, header_len + ETH_HLEN))
 453                 return 0;
 454         ethhdr = (struct ethhdr *)skb->data;
 455         header_len += ETH_HLEN;
 456
 457         /* check for initial vlan header */
 458         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
 459                 if (!pskb_may_pull(skb, header_len + VLAN_HLEN))
 460                         return 0;
 461                 ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
 462                 header_len += VLAN_HLEN;
 463         }
 464
 465         /* check for ip header */
 466         switch (ntohs(ethhdr->h_proto)) {
 467         case ETH_P_IP:
 468                 if (!pskb_may_pull(skb, header_len + sizeof(struct iphdr)))
 469                         return 0;
 470                 iphdr = (struct iphdr *)(skb->data + header_len);
 471                 header_len += iphdr->ihl * 4;
 472
 473                 /* check for udp header */
 474                 if (iphdr->protocol != IPPROTO_UDP)
 475                         return 0;
 476
 477                 break;
 478         case ETH_P_IPV6:
 479                 if (!pskb_may_pull(skb, header_len + sizeof(struct ipv6hdr)))
 480                         return 0;
 481                 ipv6hdr = (struct ipv6hdr *)(skb->data + header_len);
 482                 header_len += sizeof(struct ipv6hdr);
 483
 484                 /* check for udp header */
 485                 if (ipv6hdr->nexthdr != IPPROTO_UDP)
 486                         return 0;
 487
 488                 break;
 489         default:
 490                 return 0;
 491         }
 492
 493         if (!pskb_may_pull(skb, header_len + sizeof(struct udphdr)))
 494                 return 0;
 495         udphdr = (struct udphdr *)(skb->data + header_len);
 496         header_len += sizeof(struct udphdr);
 497
 498         /* check for bootp port */
 499         if ((ntohs(ethhdr->h_proto) == ETH_P_IP) &&
 500              (ntohs(udphdr->dest) != 67))
 501                 return 0;
 502
 503         if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
 504             (ntohs(udphdr->dest) != 547))
 505                 return 0;
 506
 507         if (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER)
 508                 return -1;
 509
 510         rcu_read_lock();
 511         if (!rcu_dereference(bat_priv->curr_gw)) {
 512                 rcu_read_unlock();
 513                 return 0;
 514         }
 515         rcu_read_unlock();
 516
 517         return 1;
 518 }