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