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         if (!orig_node)
  57                 goto out;
  58
  59         if (!atomic_inc_not_zero(&orig_node->refcount))
  60                 orig_node = NULL;
  61
  62 out:
  63         rcu_read_unlock();
  64         return orig_node;
  65 }
  66
  67 void gw_deselect(struct bat_priv *bat_priv)
  68 {
  69         struct gw_node *gw_node;
  70
  71         spin_lock_bh(&bat_priv->gw_list_lock);
  72         gw_node = rcu_dereference(bat_priv->curr_gw);
  73         rcu_assign_pointer(bat_priv->curr_gw, NULL);
  74         spin_unlock_bh(&bat_priv->gw_list_lock);
  75
  76         if (gw_node)
  77                 gw_node_free_ref(gw_node);
  78 }
  79
  80 static void gw_select(struct bat_priv *bat_priv, struct gw_node *new_gw_node)
  81 {
  82         struct gw_node *curr_gw_node;
  83
  84         if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
  85                 new_gw_node = NULL;
  86
  87         spin_lock_bh(&bat_priv->gw_list_lock);
  88         curr_gw_node = rcu_dereference(bat_priv->curr_gw);
  89         rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
  90         spin_unlock_bh(&bat_priv->gw_list_lock);
  91
  92         if (curr_gw_node)
  93                 gw_node_free_ref(curr_gw_node);
  94 }
  95
  96 void gw_election(struct bat_priv *bat_priv)
  97 {
  98         struct hlist_node *node;
  99         struct gw_node *gw_node, *curr_gw, *curr_gw_tmp = NULL;
 100         uint8_t max_tq = 0;
 101         uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
 102         int down, up;
 103
 104         /**
 105          * The batman daemon checks here if we already passed a full originator
 106          * cycle in order to make sure we don't choose the first gateway we
 107          * hear about. This check is based on the daemon's uptime which we
 108          * don't have.
 109          **/
 110         if (atomic_read(&bat_priv->gw_mode) != GW_MODE_CLIENT)
 111                 return;
 112
 113         rcu_read_lock();
 114         curr_gw = rcu_dereference(bat_priv->curr_gw);
 115         if (curr_gw) {
 116                 rcu_read_unlock();
 117                 return;
 118         }
 119
 120         if (hlist_empty(&bat_priv->gw_list)) {
 121
 122                 if (curr_gw) {
 123                         rcu_read_unlock();
 124                         bat_dbg(DBG_BATMAN, bat_priv,
 125                                 "Removing selected gateway - "
 126                                 "no gateway in range\n");
 127                         gw_deselect(bat_priv);
 128                 } else
 129                         rcu_read_unlock();
 130
 131                 return;
 132         }
 133
 134         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 135                 if (!gw_node->orig_node->router)
 136                         continue;
 137
 138                 if (gw_node->deleted)
 139                         continue;
 140
 141                 switch (atomic_read(&bat_priv->gw_sel_class)) {
 142                 case 1: /* fast connection */
 143                         gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags,
 144                                              &down, &up);
 145
 146                         tmp_gw_factor = (gw_node->orig_node->router->tq_avg *
 147                                          gw_node->orig_node->router->tq_avg *
 148                                          down * 100 * 100) /
 149                                          (TQ_LOCAL_WINDOW_SIZE *
 150                                          TQ_LOCAL_WINDOW_SIZE * 64);
 151
 152                         if ((tmp_gw_factor > max_gw_factor) ||
 153                             ((tmp_gw_factor == max_gw_factor) &&
 154                              (gw_node->orig_node->router->tq_avg > max_tq)))
 155                                 curr_gw_tmp = gw_node;
 156                         break;
 157
 158                 default: /**
 159                           * 2:  stable connection (use best statistic)
 160                           * 3:  fast-switch (use best statistic but change as
 161                           *     soon as a better gateway appears)
 162                           * XX: late-switch (use best statistic but change as
 163                           *     soon as a better gateway appears which has
 164                           *     $routing_class more tq points)
 165                           **/
 166                         if (gw_node->orig_node->router->tq_avg > max_tq)
 167                                 curr_gw_tmp = gw_node;
 168                         break;
 169                 }
 170
 171                 if (gw_node->orig_node->router->tq_avg > max_tq)
 172                         max_tq = gw_node->orig_node->router->tq_avg;
 173
 174                 if (tmp_gw_factor > max_gw_factor)
 175                         max_gw_factor = tmp_gw_factor;
 176         }
 177
 178         if (curr_gw != curr_gw_tmp) {
 179                 if ((curr_gw) && (!curr_gw_tmp))
 180                         bat_dbg(DBG_BATMAN, bat_priv,
 181                                 "Removing selected gateway - "
 182                                 "no gateway in range\n");
 183                 else if ((!curr_gw) && (curr_gw_tmp))
 184                         bat_dbg(DBG_BATMAN, bat_priv,
 185                                 "Adding route to gateway %pM "
 186                                 "(gw_flags: %i, tq: %i)\n",
 187                                 curr_gw_tmp->orig_node->orig,
 188                                 curr_gw_tmp->orig_node->gw_flags,
 189                                 curr_gw_tmp->orig_node->router->tq_avg);
 190                 else
 191                         bat_dbg(DBG_BATMAN, bat_priv,
 192                                 "Changing route to gateway %pM "
 193                                 "(gw_flags: %i, tq: %i)\n",
 194                                 curr_gw_tmp->orig_node->orig,
 195                                 curr_gw_tmp->orig_node->gw_flags,
 196                                 curr_gw_tmp->orig_node->router->tq_avg);
 197
 198                 gw_select(bat_priv, curr_gw_tmp);
 199         }
 200
 201         rcu_read_unlock();
 202 }
 203
 204 void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
 205 {
 206         struct gw_node *curr_gateway_tmp;
 207         uint8_t gw_tq_avg, orig_tq_avg;
 208
 209         rcu_read_lock();
 210         curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
 211         if (!curr_gateway_tmp)
 212                 goto out_rcu;
 213
 214         if (!curr_gateway_tmp->orig_node)
 215                 goto deselect_rcu;
 216
 217         if (!curr_gateway_tmp->orig_node->router)
 218                 goto deselect_rcu;
 219
 220         /* this node already is the gateway */
 221         if (curr_gateway_tmp->orig_node == orig_node)
 222                 goto out_rcu;
 223
 224         if (!orig_node->router)
 225                 goto out_rcu;
 226
 227         gw_tq_avg = curr_gateway_tmp->orig_node->router->tq_avg;
 228         rcu_read_unlock();
 229
 230         orig_tq_avg = orig_node->router->tq_avg;
 231
 232         /* the TQ value has to be better */
 233         if (orig_tq_avg < gw_tq_avg)
 234                 goto out;
 235
 236         /**
 237          * if the routing class is greater than 3 the value tells us how much
 238          * greater the TQ value of the new gateway must be
 239          **/
 240         if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
 241             (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
 242                 goto out;
 243
 244         bat_dbg(DBG_BATMAN, bat_priv,
 245                 "Restarting gateway selection: better gateway found (tq curr: "
 246                 "%i, tq new: %i)\n",
 247                 gw_tq_avg, orig_tq_avg);
 248         goto deselect;
 249
 250 out_rcu:
 251         rcu_read_unlock();
 252         goto out;
 253 deselect_rcu:
 254         rcu_read_unlock();
 255 deselect:
 256         gw_deselect(bat_priv);
 257 out:
 258         return;
 259 }
 260
 261 static void gw_node_add(struct bat_priv *bat_priv,
 262                         struct orig_node *orig_node, uint8_t new_gwflags)
 263 {
 264         struct gw_node *gw_node;
 265         int down, up;
 266
 267         gw_node = kmalloc(sizeof(struct gw_node), GFP_ATOMIC);
 268         if (!gw_node)
 269                 return;
 270
 271         memset(gw_node, 0, sizeof(struct gw_node));
 272         INIT_HLIST_NODE(&gw_node->list);
 273         gw_node->orig_node = orig_node;
 274         atomic_set(&gw_node->refcount, 1);
 275
 276         spin_lock_bh(&bat_priv->gw_list_lock);
 277         hlist_add_head_rcu(&gw_node->list, &bat_priv->gw_list);
 278         spin_unlock_bh(&bat_priv->gw_list_lock);
 279
 280         gw_bandwidth_to_kbit(new_gwflags, &down, &up);
 281         bat_dbg(DBG_BATMAN, bat_priv,
 282                 "Found new gateway %pM -> gw_class: %i - %i%s/%i%s\n",
 283                 orig_node->orig, new_gwflags,
 284                 (down > 2048 ? down / 1024 : down),
 285                 (down > 2048 ? "MBit" : "KBit"),
 286                 (up > 2048 ? up / 1024 : up),
 287                 (up > 2048 ? "MBit" : "KBit"));
 288 }
 289
 290 void gw_node_update(struct bat_priv *bat_priv,
 291                     struct orig_node *orig_node, uint8_t new_gwflags)
 292 {
 293         struct hlist_node *node;
 294         struct gw_node *gw_node;
 295
 296         rcu_read_lock();
 297         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 298                 if (gw_node->orig_node != orig_node)
 299                         continue;
 300
 301                 bat_dbg(DBG_BATMAN, bat_priv,
 302                         "Gateway class of originator %pM changed from "
 303                         "%i to %i\n",
 304                         orig_node->orig, gw_node->orig_node->gw_flags,
 305                         new_gwflags);
 306
 307                 gw_node->deleted = 0;
 308
 309                 if (new_gwflags == 0) {
 310                         gw_node->deleted = jiffies;
 311                         bat_dbg(DBG_BATMAN, bat_priv,
 312                                 "Gateway %pM removed from gateway list\n",
 313                                 orig_node->orig);
 314
 315                         if (gw_node == rcu_dereference(bat_priv->curr_gw)) {
 316                                 rcu_read_unlock();
 317                                 gw_deselect(bat_priv);
 318                                 return;
 319                         }
 320                 }
 321
 322                 rcu_read_unlock();
 323                 return;
 324         }
 325         rcu_read_unlock();
 326
 327         if (new_gwflags == 0)
 328                 return;
 329
 330         gw_node_add(bat_priv, orig_node, new_gwflags);
 331 }
 332
 333 void gw_node_delete(struct bat_priv *bat_priv, struct orig_node *orig_node)
 334 {
 335         return gw_node_update(bat_priv, orig_node, 0);
 336 }
 337
 338 void gw_node_purge(struct bat_priv *bat_priv)
 339 {
 340         struct gw_node *gw_node;
 341         struct hlist_node *node, *node_tmp;
 342         unsigned long timeout = 2 * PURGE_TIMEOUT * HZ;
 343
 344         spin_lock_bh(&bat_priv->gw_list_lock);
 345
 346         hlist_for_each_entry_safe(gw_node, node, node_tmp,
 347                                   &bat_priv->gw_list, list) {
 348                 if (((!gw_node->deleted) ||
 349                      (time_before(jiffies, gw_node->deleted + timeout))) &&
 350                     atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE)
 351                         continue;
 352
 353                 if (rcu_dereference(bat_priv->curr_gw) == gw_node)
 354                         gw_deselect(bat_priv);
 355
 356                 hlist_del_rcu(&gw_node->list);
 357                 gw_node_free_ref(gw_node);
 358         }
 359
 360
 361         spin_unlock_bh(&bat_priv->gw_list_lock);
 362 }
 363
 364 static int _write_buffer_text(struct bat_priv *bat_priv,
 365                               struct seq_file *seq, struct gw_node *gw_node)
 366 {
 367         struct gw_node *curr_gw;
 368         int down, up, ret;
 369
 370         gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);
 371
 372         rcu_read_lock();
 373         curr_gw = rcu_dereference(bat_priv->curr_gw);
 374
 375         ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
 376                        (curr_gw == gw_node ? "=>" : "  "),
 377                        gw_node->orig_node->orig,
 378                        gw_node->orig_node->router->tq_avg,
 379                        gw_node->orig_node->router->addr,
 380                        gw_node->orig_node->router->if_incoming->net_dev->name,
 381                        gw_node->orig_node->gw_flags,
 382                        (down > 2048 ? down / 1024 : down),
 383                        (down > 2048 ? "MBit" : "KBit"),
 384                        (up > 2048 ? up / 1024 : up),
 385                        (up > 2048 ? "MBit" : "KBit"));
 386
 387         rcu_read_unlock();
 388         return ret;
 389 }
 390
 391 int gw_client_seq_print_text(struct seq_file *seq, void *offset)
 392 {
 393         struct net_device *net_dev = (struct net_device *)seq->private;
 394         struct bat_priv *bat_priv = netdev_priv(net_dev);
 395         struct gw_node *gw_node;
 396         struct hlist_node *node;
 397         int gw_count = 0;
 398
 399         if (!bat_priv->primary_if) {
 400
 401                 return seq_printf(seq, "BATMAN mesh %s disabled - please "
 402                                   "specify interfaces to enable it\n",
 403                                   net_dev->name);
 404         }
 405
 406         if (bat_priv->primary_if->if_status != IF_ACTIVE) {
 407
 408                 return seq_printf(seq, "BATMAN mesh %s disabled - "
 409                                        "primary interface not active\n",
 410                                        net_dev->name);
 411         }
 412
 413         seq_printf(seq, "      %-12s (%s/%i) %17s [%10s]: gw_class ... "
 414                    "[B.A.T.M.A.N. adv %s%s, MainIF/MAC: %s/%pM (%s)]\n",
 415                    "Gateway", "#", TQ_MAX_VALUE, "Nexthop",
 416                    "outgoingIF", SOURCE_VERSION, REVISION_VERSION_STR,
 417                    bat_priv->primary_if->net_dev->name,
 418                    bat_priv->primary_if->net_dev->dev_addr, net_dev->name);
 419
 420         rcu_read_lock();
 421         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 422                 if (gw_node->deleted)
 423                         continue;
 424
 425                 if (!gw_node->orig_node->router)
 426                         continue;
 427
 428                 _write_buffer_text(bat_priv, seq, gw_node);
 429                 gw_count++;
 430         }
 431         rcu_read_unlock();
 432
 433         if (gw_count == 0)
 434                 seq_printf(seq, "No gateways in range ...\n");
 435
 436         return 0;
 437 }
 438
 439 int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb)
 440 {
 441         struct ethhdr *ethhdr;
 442         struct iphdr *iphdr;
 443         struct ipv6hdr *ipv6hdr;
 444         struct udphdr *udphdr;
 445         unsigned int header_len = 0;
 446
 447         if (atomic_read(&bat_priv->gw_mode) == GW_MODE_OFF)
 448                 return 0;
 449
 450         /* check for ethernet header */
 451         if (!pskb_may_pull(skb, header_len + ETH_HLEN))
 452                 return 0;
 453         ethhdr = (struct ethhdr *)skb->data;
 454         header_len += ETH_HLEN;
 455
 456         /* check for initial vlan header */
 457         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
 458                 if (!pskb_may_pull(skb, header_len + VLAN_HLEN))
 459                         return 0;
 460                 ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
 461                 header_len += VLAN_HLEN;
 462         }
 463
 464         /* check for ip header */
 465         switch (ntohs(ethhdr->h_proto)) {
 466         case ETH_P_IP:
 467                 if (!pskb_may_pull(skb, header_len + sizeof(struct iphdr)))
 468                         return 0;
 469                 iphdr = (struct iphdr *)(skb->data + header_len);
 470                 header_len += iphdr->ihl * 4;
 471
 472                 /* check for udp header */
 473                 if (iphdr->protocol != IPPROTO_UDP)
 474                         return 0;
 475
 476                 break;
 477         case ETH_P_IPV6:
 478                 if (!pskb_may_pull(skb, header_len + sizeof(struct ipv6hdr)))
 479                         return 0;
 480                 ipv6hdr = (struct ipv6hdr *)(skb->data + header_len);
 481                 header_len += sizeof(struct ipv6hdr);
 482
 483                 /* check for udp header */
 484                 if (ipv6hdr->nexthdr != IPPROTO_UDP)
 485                         return 0;
 486
 487                 break;
 488         default:
 489                 return 0;
 490         }
 491
 492         if (!pskb_may_pull(skb, header_len + sizeof(struct udphdr)))
 493                 return 0;
 494         udphdr = (struct udphdr *)(skb->data + header_len);
 495         header_len += sizeof(struct udphdr);
 496
 497         /* check for bootp port */
 498         if ((ntohs(ethhdr->h_proto) == ETH_P_IP) &&
 499              (ntohs(udphdr->dest) != 67))
 500                 return 0;
 501
 502         if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
 503             (ntohs(udphdr->dest) != 547))
 504                 return 0;
 505
 506         if (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER)
 507                 return -1;
 508
 509         rcu_read_lock();
 510         if (!rcu_dereference(bat_priv->curr_gw)) {
 511                 rcu_read_unlock();
 512                 return 0;
 513         }
 514         rcu_read_unlock();
 515
 516         return 1;
 517 }