net/tipc/link.c

   1 /*
   2  * net/tipc/link.c: TIPC link code
   3  *
   4  * Copyright (c) 1996-2007, 2012-2015, Ericsson AB
   5  * Copyright (c) 2004-2007, 2010-2013, Wind River Systems
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the names of the copyright holders nor the names of its
  17  *    contributors may be used to endorse or promote products derived from
  18  *    this software without specific prior written permission.
  19  *
  20  * Alternatively, this software may be distributed under the terms of the
  21  * GNU General Public License ("GPL") version 2 as published by the Free
  22  * Software Foundation.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34  * POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include "core.h"
  38 #include "subscr.h"
  39 #include "link.h"
  40 #include "bcast.h"
  41 #include "socket.h"
  42 #include "name_distr.h"
  43 #include "discover.h"
  44 #include "netlink.h"
  45
  46 #include <linux/pkt_sched.h>
  47
  48 /*
  49  * Error message prefixes
  50  */
  51 static const char *link_co_err = "Link changeover error, ";
  52 static const char *link_rst_msg = "Resetting link ";
  53 static const char *link_unk_evt = "Unknown link event ";
  54
  55 static const struct nla_policy tipc_nl_link_policy[TIPC_NLA_LINK_MAX + 1] = {
  56         [TIPC_NLA_LINK_UNSPEC]          = { .type = NLA_UNSPEC },
  57         [TIPC_NLA_LINK_NAME] = {
  58                 .type = NLA_STRING,
  59                 .len = TIPC_MAX_LINK_NAME
  60         },
  61         [TIPC_NLA_LINK_MTU]             = { .type = NLA_U32 },
  62         [TIPC_NLA_LINK_BROADCAST]       = { .type = NLA_FLAG },
  63         [TIPC_NLA_LINK_UP]              = { .type = NLA_FLAG },
  64         [TIPC_NLA_LINK_ACTIVE]          = { .type = NLA_FLAG },
  65         [TIPC_NLA_LINK_PROP]            = { .type = NLA_NESTED },
  66         [TIPC_NLA_LINK_STATS]           = { .type = NLA_NESTED },
  67         [TIPC_NLA_LINK_RX]              = { .type = NLA_U32 },
  68         [TIPC_NLA_LINK_TX]              = { .type = NLA_U32 }
  69 };
  70
  71 /* Properties valid for media, bearar and link */
  72 static const struct nla_policy tipc_nl_prop_policy[TIPC_NLA_PROP_MAX + 1] = {
  73         [TIPC_NLA_PROP_UNSPEC]          = { .type = NLA_UNSPEC },
  74         [TIPC_NLA_PROP_PRIO]            = { .type = NLA_U32 },
  75         [TIPC_NLA_PROP_TOL]             = { .type = NLA_U32 },
  76         [TIPC_NLA_PROP_WIN]             = { .type = NLA_U32 }
  77 };
  78
  79 /*
  80  * Out-of-range value for link session numbers
  81  */
  82 #define WILDCARD_SESSION 0x10000
  83
  84 /* State value stored in 'failover_pkts'
  85  */
  86 #define FIRST_FAILOVER 0xffffu
  87
  88 /* Link FSM states and events:
  89  */
  90 enum {
  91         TIPC_LINK_WORKING,
  92         TIPC_LINK_PROBING,
  93         TIPC_LINK_RESETTING,
  94         TIPC_LINK_ESTABLISHING
  95 };
  96
  97 enum {
  98         PEER_RESET_EVT    = RESET_MSG,
  99         ACTIVATE_EVT      = ACTIVATE_MSG,
 100         TRAFFIC_EVT,      /* Any other valid msg from peer */
 101         SILENCE_EVT       /* Peer was silent during last timer interval*/
 102 };
 103
 104 /* Link FSM state checking routines
 105  */
 106 static int link_working(struct tipc_link *l)
 107 {
 108         return l->state == TIPC_LINK_WORKING;
 109 }
 110
 111 static int link_probing(struct tipc_link *l)
 112 {
 113         return l->state == TIPC_LINK_PROBING;
 114 }
 115
 116 static int link_resetting(struct tipc_link *l)
 117 {
 118         return l->state == TIPC_LINK_RESETTING;
 119 }
 120
 121 static int link_establishing(struct tipc_link *l)
 122 {
 123         return l->state == TIPC_LINK_ESTABLISHING;
 124 }
 125
 126 static void link_handle_out_of_seq_msg(struct tipc_link *link,
 127                                        struct sk_buff *skb);
 128 static void tipc_link_proto_rcv(struct tipc_link *link,
 129                                 struct sk_buff *skb);
 130 static void link_state_event(struct tipc_link *l_ptr, u32 event);
 131 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
 132                                       u16 rcvgap, int tolerance, int priority,
 133                                       struct sk_buff_head *xmitq);
 134 static void link_reset_statistics(struct tipc_link *l_ptr);
 135 static void link_print(struct tipc_link *l_ptr, const char *str);
 136 static void tipc_link_sync_xmit(struct tipc_link *l);
 137 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf);
 138 static void tipc_link_input(struct tipc_link *l, struct sk_buff *skb);
 139 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb);
 140 static bool tipc_link_failover_rcv(struct tipc_link *l, struct sk_buff **skb);
 141 static void link_activate(struct tipc_link *link);
 142
 143 /*
 144  *  Simple link routines
 145  */
 146 static unsigned int align(unsigned int i)
 147 {
 148         return (i + 3) & ~3u;
 149 }
 150
 151 static struct tipc_link *tipc_parallel_link(struct tipc_link *l)
 152 {
 153         struct tipc_node *n = l->owner;
 154
 155         if (node_active_link(n, 0) != l)
 156                 return node_active_link(n, 0);
 157         return node_active_link(n, 1);
 158 }
 159
 160 /*
 161  *  Simple non-static link routines (i.e. referenced outside this file)
 162  */
 163 int tipc_link_is_up(struct tipc_link *l_ptr)
 164 {
 165         if (!l_ptr)
 166                 return 0;
 167         return link_working(l_ptr) || link_probing(l_ptr);
 168 }
 169
 170 int tipc_link_is_active(struct tipc_link *l)
 171 {
 172         struct tipc_node *n = l->owner;
 173
 174         return (node_active_link(n, 0) == l) || (node_active_link(n, 1) == l);
 175 }
 176
 177 /**
 178  * tipc_link_create - create a new link
 179  * @n_ptr: pointer to associated node
 180  * @b_ptr: pointer to associated bearer
 181  * @media_addr: media address to use when sending messages over link
 182  *
 183  * Returns pointer to link.
 184  */
 185 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
 186                                    struct tipc_bearer *b_ptr,
 187                                    const struct tipc_media_addr *media_addr,
 188                                    struct sk_buff_head *inputq,
 189                                    struct sk_buff_head *namedq)
 190 {
 191         struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
 192         struct tipc_link *l_ptr;
 193         struct tipc_msg *msg;
 194         char *if_name;
 195         char addr_string[16];
 196         u32 peer = n_ptr->addr;
 197
 198         if (n_ptr->link_cnt >= MAX_BEARERS) {
 199                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 200                 pr_err("Cannot establish %uth link to %s. Max %u allowed.\n",
 201                        n_ptr->link_cnt, addr_string, MAX_BEARERS);
 202                 return NULL;
 203         }
 204
 205         if (n_ptr->links[b_ptr->identity].link) {
 206                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 207                 pr_err("Attempt to establish second link on <%s> to %s\n",
 208                        b_ptr->name, addr_string);
 209                 return NULL;
 210         }
 211
 212         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 213         if (!l_ptr) {
 214                 pr_warn("Link creation failed, no memory\n");
 215                 return NULL;
 216         }
 217         l_ptr->addr = peer;
 218         if_name = strchr(b_ptr->name, ':') + 1;
 219         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 220                 tipc_zone(tn->own_addr), tipc_cluster(tn->own_addr),
 221                 tipc_node(tn->own_addr),
 222                 if_name,
 223                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 224                 /* note: peer i/f name is updated by reset/activate message */
 225         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 226         l_ptr->owner = n_ptr;
 227         l_ptr->peer_session = WILDCARD_SESSION;
 228         l_ptr->bearer_id = b_ptr->identity;
 229         l_ptr->tolerance = b_ptr->tolerance;
 230         l_ptr->state = TIPC_LINK_RESETTING;
 231
 232         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 233         msg = l_ptr->pmsg;
 234         tipc_msg_init(tn->own_addr, msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE,
 235                       l_ptr->addr);
 236         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 237         msg_set_session(msg, (tn->random & 0xffff));
 238         msg_set_bearer_id(msg, b_ptr->identity);
 239         strcpy((char *)msg_data(msg), if_name);
 240         l_ptr->net_plane = b_ptr->net_plane;
 241         l_ptr->advertised_mtu = b_ptr->mtu;
 242         l_ptr->mtu = l_ptr->advertised_mtu;
 243         l_ptr->priority = b_ptr->priority;
 244         tipc_link_set_queue_limits(l_ptr, b_ptr->window);
 245         l_ptr->snd_nxt = 1;
 246         __skb_queue_head_init(&l_ptr->transmq);
 247         __skb_queue_head_init(&l_ptr->backlogq);
 248         __skb_queue_head_init(&l_ptr->deferdq);
 249         skb_queue_head_init(&l_ptr->wakeupq);
 250         l_ptr->inputq = inputq;
 251         l_ptr->namedq = namedq;
 252         skb_queue_head_init(l_ptr->inputq);
 253         link_reset_statistics(l_ptr);
 254         tipc_node_attach_link(n_ptr, l_ptr);
 255         return l_ptr;
 256 }
 257
 258 /**
 259  * tipc_link_delete - Delete a link
 260  * @l: link to be deleted
 261  */
 262 void tipc_link_delete(struct tipc_link *l)
 263 {
 264         tipc_link_reset(l);
 265         tipc_link_reset_fragments(l);
 266         tipc_node_detach_link(l->owner, l);
 267 }
 268
 269 void tipc_link_delete_list(struct net *net, unsigned int bearer_id)
 270 {
 271         struct tipc_net *tn = net_generic(net, tipc_net_id);
 272         struct tipc_link *link;
 273         struct tipc_node *node;
 274
 275         rcu_read_lock();
 276         list_for_each_entry_rcu(node, &tn->node_list, list) {
 277                 tipc_node_lock(node);
 278                 link = node->links[bearer_id].link;
 279                 if (link)
 280                         tipc_link_delete(link);
 281                 tipc_node_unlock(node);
 282         }
 283         rcu_read_unlock();
 284 }
 285
 286 /**
 287  * tipc_link_fsm_evt - link finite state machine
 288  * @l: pointer to link
 289  * @evt: state machine event to be processed
 290  * @xmitq: queue to prepend created protocol message, if any
 291  */
 292 static int tipc_link_fsm_evt(struct tipc_link *l, int evt,
 293                              struct sk_buff_head *xmitq)
 294 {
 295         int mtyp = 0, rc = 0;
 296         struct tipc_link *pl;
 297         enum {
 298                 LINK_RESET    = 1,
 299                 LINK_ACTIVATE = (1 << 1),
 300                 SND_PROBE     = (1 << 2),
 301                 SND_STATE     = (1 << 3),
 302                 SND_RESET     = (1 << 4),
 303                 SND_ACTIVATE  = (1 << 5)
 304         } actions = 0;
 305
 306         if (l->exec_mode == TIPC_LINK_BLOCKED)
 307                 return rc;
 308
 309         switch (l->state) {
 310         case TIPC_LINK_WORKING:
 311                 switch (evt) {
 312                 case TRAFFIC_EVT:
 313                 case ACTIVATE_EVT:
 314                         break;
 315                 case SILENCE_EVT:
 316                         l->state = TIPC_LINK_PROBING;
 317                         actions |= SND_PROBE;
 318                         break;
 319                 case PEER_RESET_EVT:
 320                         actions |= LINK_RESET | SND_ACTIVATE;
 321                         break;
 322                 default:
 323                         pr_debug("%s%u WORKING\n", link_unk_evt, evt);
 324                 }
 325                 break;
 326         case TIPC_LINK_PROBING:
 327                 switch (evt) {
 328                 case TRAFFIC_EVT:
 329                 case ACTIVATE_EVT:
 330                         l->state = TIPC_LINK_WORKING;
 331                         break;
 332                 case PEER_RESET_EVT:
 333                         actions |= LINK_RESET | SND_ACTIVATE;
 334                         break;
 335                 case SILENCE_EVT:
 336                         if (l->silent_intv_cnt <= l->abort_limit) {
 337                                 actions |= SND_PROBE;
 338                                 break;
 339                         }
 340                         actions |= LINK_RESET | SND_RESET;
 341                         break;
 342                 default:
 343                         pr_err("%s%u PROBING\n", link_unk_evt, evt);
 344                 }
 345                 break;
 346         case TIPC_LINK_RESETTING:
 347                 switch (evt) {
 348                 case TRAFFIC_EVT:
 349                         break;
 350                 case ACTIVATE_EVT:
 351                         pl = node_active_link(l->owner, 0);
 352                         if (pl && link_probing(pl))
 353                                 break;
 354                         actions |= LINK_ACTIVATE;
 355                         if (l->owner->working_links == 1)
 356                                 tipc_link_sync_xmit(l);
 357                         break;
 358                 case PEER_RESET_EVT:
 359                         l->state = TIPC_LINK_ESTABLISHING;
 360                         actions |= SND_ACTIVATE;
 361                         break;
 362                 case SILENCE_EVT:
 363                         actions |= SND_RESET;
 364                         break;
 365                 default:
 366                         pr_err("%s%u in RESETTING\n", link_unk_evt, evt);
 367                 }
 368                 break;
 369         case TIPC_LINK_ESTABLISHING:
 370                 switch (evt) {
 371                 case TRAFFIC_EVT:
 372                 case ACTIVATE_EVT:
 373                         pl = node_active_link(l->owner, 0);
 374                         if (pl && link_probing(pl))
 375                                 break;
 376                         actions |= LINK_ACTIVATE;
 377                         if (l->owner->working_links == 1)
 378                                 tipc_link_sync_xmit(l);
 379                         break;
 380                 case PEER_RESET_EVT:
 381                         break;
 382                 case SILENCE_EVT:
 383                         actions |= SND_ACTIVATE;
 384                         break;
 385                 default:
 386                         pr_err("%s%u ESTABLISHING\n", link_unk_evt, evt);
 387                 }
 388                 break;
 389         default:
 390                 pr_err("Unknown link state %u/%u\n", l->state, evt);
 391         }
 392
 393         /* Perform actions as decided by FSM */
 394         if (actions & LINK_RESET) {
 395                 l->exec_mode = TIPC_LINK_BLOCKED;
 396                 rc |= TIPC_LINK_DOWN_EVT;
 397         }
 398         if (actions & LINK_ACTIVATE) {
 399                 l->exec_mode = TIPC_LINK_OPEN;
 400                 rc |= TIPC_LINK_UP_EVT;
 401         }
 402         if (actions & (SND_STATE | SND_PROBE))
 403                 mtyp = STATE_MSG;
 404         if (actions & SND_RESET)
 405                 mtyp = RESET_MSG;
 406         if (actions & SND_ACTIVATE)
 407                 mtyp = ACTIVATE_MSG;
 408         if (actions & (SND_PROBE | SND_STATE | SND_RESET | SND_ACTIVATE))
 409                 tipc_link_build_proto_msg(l, mtyp, actions & SND_PROBE,
 410                                           0, 0, 0, xmitq);
 411         return rc;
 412 }
 413
 414 /* link_profile_stats - update statistical profiling of traffic
 415  */
 416 static void link_profile_stats(struct tipc_link *l)
 417 {
 418         struct sk_buff *skb;
 419         struct tipc_msg *msg;
 420         int length;
 421
 422         /* Update counters used in statistical profiling of send traffic */
 423         l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
 424         l->stats.queue_sz_counts++;
 425
 426         skb = skb_peek(&l->transmq);
 427         if (!skb)
 428                 return;
 429         msg = buf_msg(skb);
 430         length = msg_size(msg);
 431
 432         if (msg_user(msg) == MSG_FRAGMENTER) {
 433                 if (msg_type(msg) != FIRST_FRAGMENT)
 434                         return;
 435                 length = msg_size(msg_get_wrapped(msg));
 436         }
 437         l->stats.msg_lengths_total += length;
 438         l->stats.msg_length_counts++;
 439         if (length <= 64)
 440                 l->stats.msg_length_profile[0]++;
 441         else if (length <= 256)
 442                 l->stats.msg_length_profile[1]++;
 443         else if (length <= 1024)
 444                 l->stats.msg_length_profile[2]++;
 445         else if (length <= 4096)
 446                 l->stats.msg_length_profile[3]++;
 447         else if (length <= 16384)
 448                 l->stats.msg_length_profile[4]++;
 449         else if (length <= 32768)
 450                 l->stats.msg_length_profile[5]++;
 451         else
 452                 l->stats.msg_length_profile[6]++;
 453 }
 454
 455 /* tipc_link_timeout - perform periodic task as instructed from node timeout
 456  */
 457 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
 458 {
 459         int rc = 0;
 460
 461         link_profile_stats(l);
 462         if (l->silent_intv_cnt)
 463                 rc = tipc_link_fsm_evt(l, SILENCE_EVT, xmitq);
 464         else if (link_working(l) && tipc_bclink_acks_missing(l->owner))
 465                 tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, xmitq);
 466         l->silent_intv_cnt++;
 467         return rc;
 468 }
 469
 470 /**
 471  * link_schedule_user - schedule a message sender for wakeup after congestion
 472  * @link: congested link
 473  * @list: message that was attempted sent
 474  * Create pseudo msg to send back to user when congestion abates
 475  * Does not consume buffer list
 476  */
 477 static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
 478 {
 479         struct tipc_msg *msg = buf_msg(skb_peek(list));
 480         int imp = msg_importance(msg);
 481         u32 oport = msg_origport(msg);
 482         u32 addr = link_own_addr(link);
 483         struct sk_buff *skb;
 484
 485         /* This really cannot happen...  */
 486         if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
 487                 pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
 488                 return -ENOBUFS;
 489         }
 490         /* Non-blocking sender: */
 491         if (TIPC_SKB_CB(skb_peek(list))->wakeup_pending)
 492                 return -ELINKCONG;
 493
 494         /* Create and schedule wakeup pseudo message */
 495         skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
 496                               addr, addr, oport, 0, 0);
 497         if (!skb)
 498                 return -ENOBUFS;
 499         TIPC_SKB_CB(skb)->chain_sz = skb_queue_len(list);
 500         TIPC_SKB_CB(skb)->chain_imp = imp;
 501         skb_queue_tail(&link->wakeupq, skb);
 502         link->stats.link_congs++;
 503         return -ELINKCONG;
 504 }
 505
 506 /**
 507  * link_prepare_wakeup - prepare users for wakeup after congestion
 508  * @link: congested link
 509  * Move a number of waiting users, as permitted by available space in
 510  * the send queue, from link wait queue to node wait queue for wakeup
 511  */
 512 void link_prepare_wakeup(struct tipc_link *l)
 513 {
 514         int pnd[TIPC_SYSTEM_IMPORTANCE + 1] = {0,};
 515         int imp, lim;
 516         struct sk_buff *skb, *tmp;
 517
 518         skb_queue_walk_safe(&l->wakeupq, skb, tmp) {
 519                 imp = TIPC_SKB_CB(skb)->chain_imp;
 520                 lim = l->window + l->backlog[imp].limit;
 521                 pnd[imp] += TIPC_SKB_CB(skb)->chain_sz;
 522                 if ((pnd[imp] + l->backlog[imp].len) >= lim)
 523                         break;
 524                 skb_unlink(skb, &l->wakeupq);
 525                 skb_queue_tail(l->inputq, skb);
 526                 l->owner->inputq = l->inputq;
 527                 l->owner->action_flags |= TIPC_MSG_EVT;
 528         }
 529 }
 530
 531 /**
 532  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 533  * @l_ptr: pointer to link
 534  */
 535 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 536 {
 537         kfree_skb(l_ptr->reasm_buf);
 538         l_ptr->reasm_buf = NULL;
 539 }
 540
 541 void tipc_link_purge_backlog(struct tipc_link *l)
 542 {
 543         __skb_queue_purge(&l->backlogq);
 544         l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
 545         l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
 546         l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
 547         l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
 548         l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
 549 }
 550
 551 /**
 552  * tipc_link_purge_queues - purge all pkt queues associated with link
 553  * @l_ptr: pointer to link
 554  */
 555 void tipc_link_purge_queues(struct tipc_link *l_ptr)
 556 {
 557         __skb_queue_purge(&l_ptr->deferdq);
 558         __skb_queue_purge(&l_ptr->transmq);
 559         tipc_link_purge_backlog(l_ptr);
 560         tipc_link_reset_fragments(l_ptr);
 561 }
 562
 563 void tipc_link_reset(struct tipc_link *l_ptr)
 564 {
 565         u32 prev_state = l_ptr->state;
 566         int was_active_link = tipc_link_is_active(l_ptr);
 567         struct tipc_node *owner = l_ptr->owner;
 568         struct tipc_link *pl = tipc_parallel_link(l_ptr);
 569
 570         msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
 571
 572         /* Link is down, accept any session */
 573         l_ptr->peer_session = WILDCARD_SESSION;
 574
 575         /* Prepare for renewed mtu size negotiation */
 576         l_ptr->mtu = l_ptr->advertised_mtu;
 577
 578         l_ptr->state = TIPC_LINK_RESETTING;
 579
 580         if ((prev_state == TIPC_LINK_RESETTING) ||
 581             (prev_state == TIPC_LINK_ESTABLISHING))
 582                 return;
 583
 584         tipc_node_link_down(l_ptr->owner, l_ptr->bearer_id);
 585         tipc_bearer_remove_dest(owner->net, l_ptr->bearer_id, l_ptr->addr);
 586
 587         if (was_active_link && tipc_node_is_up(l_ptr->owner) && (pl != l_ptr)) {
 588                 l_ptr->exec_mode = TIPC_LINK_BLOCKED;
 589                 l_ptr->failover_checkpt = l_ptr->rcv_nxt;
 590                 pl->failover_pkts = FIRST_FAILOVER;
 591                 pl->failover_checkpt = l_ptr->rcv_nxt;
 592                 pl->failover_skb = l_ptr->reasm_buf;
 593         } else {
 594                 kfree_skb(l_ptr->reasm_buf);
 595         }
 596         /* Clean up all queues, except inputq: */
 597         __skb_queue_purge(&l_ptr->transmq);
 598         __skb_queue_purge(&l_ptr->deferdq);
 599         if (!owner->inputq)
 600                 owner->inputq = l_ptr->inputq;
 601         skb_queue_splice_init(&l_ptr->wakeupq, owner->inputq);
 602         if (!skb_queue_empty(owner->inputq))
 603                 owner->action_flags |= TIPC_MSG_EVT;
 604         tipc_link_purge_backlog(l_ptr);
 605         l_ptr->reasm_buf = NULL;
 606         l_ptr->rcv_unacked = 0;
 607         l_ptr->snd_nxt = 1;
 608         l_ptr->silent_intv_cnt = 0;
 609         l_ptr->stale_count = 0;
 610         link_reset_statistics(l_ptr);
 611 }
 612
 613 static void link_activate(struct tipc_link *link)
 614 {
 615         struct tipc_node *node = link->owner;
 616
 617         link->rcv_nxt = 1;
 618         link->stats.recv_info = 1;
 619         link->silent_intv_cnt = 0;
 620         link->state = TIPC_LINK_WORKING;
 621         link->exec_mode = TIPC_LINK_OPEN;
 622         tipc_node_link_up(node, link->bearer_id);
 623         tipc_bearer_add_dest(node->net, link->bearer_id, link->addr);
 624 }
 625
 626 /**
 627  * link_state_event - link finite state machine
 628  * @l_ptr: pointer to link
 629  * @event: state machine event to process
 630  */
 631 static void link_state_event(struct tipc_link *l, unsigned int evt)
 632 {
 633         int rc;
 634         struct sk_buff_head xmitq;
 635         struct sk_buff *skb;
 636
 637         if (l->exec_mode == TIPC_LINK_BLOCKED)
 638                 return;
 639
 640         __skb_queue_head_init(&xmitq);
 641
 642         rc = tipc_link_fsm_evt(l, evt, &xmitq);
 643
 644         if (rc & TIPC_LINK_UP_EVT)
 645                 link_activate(l);
 646
 647         if (rc & TIPC_LINK_DOWN_EVT)
 648                 tipc_link_reset(l);
 649
 650         skb = __skb_dequeue(&xmitq);
 651         if (!skb)
 652                 return;
 653         tipc_bearer_send(l->owner->net, l->bearer_id, skb, &l->media_addr);
 654 }
 655
 656 /**
 657  * __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
 658  * @link: link to use
 659  * @list: chain of buffers containing message
 660  *
 661  * Consumes the buffer chain, except when returning an error code,
 662  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 663  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 664  */
 665 int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 666                      struct sk_buff_head *list)
 667 {
 668         struct tipc_msg *msg = buf_msg(skb_peek(list));
 669         unsigned int maxwin = link->window;
 670         unsigned int i, imp = msg_importance(msg);
 671         uint mtu = link->mtu;
 672         u16 ack = mod(link->rcv_nxt - 1);
 673         u16 seqno = link->snd_nxt;
 674         u16 bc_last_in = link->owner->bclink.last_in;
 675         struct tipc_media_addr *addr = &link->media_addr;
 676         struct sk_buff_head *transmq = &link->transmq;
 677         struct sk_buff_head *backlogq = &link->backlogq;
 678         struct sk_buff *skb, *bskb;
 679
 680         /* Match msg importance against this and all higher backlog limits: */
 681         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 682                 if (unlikely(link->backlog[i].len >= link->backlog[i].limit))
 683                         return link_schedule_user(link, list);
 684         }
 685         if (unlikely(msg_size(msg) > mtu))
 686                 return -EMSGSIZE;
 687
 688         /* Prepare each packet for sending, and add to relevant queue: */
 689         while (skb_queue_len(list)) {
 690                 skb = skb_peek(list);
 691                 msg = buf_msg(skb);
 692                 msg_set_seqno(msg, seqno);
 693                 msg_set_ack(msg, ack);
 694                 msg_set_bcast_ack(msg, bc_last_in);
 695
 696                 if (likely(skb_queue_len(transmq) < maxwin)) {
 697                         __skb_dequeue(list);
 698                         __skb_queue_tail(transmq, skb);
 699                         tipc_bearer_send(net, link->bearer_id, skb, addr);
 700                         link->rcv_unacked = 0;
 701                         seqno++;
 702                         continue;
 703                 }
 704                 if (tipc_msg_bundle(skb_peek_tail(backlogq), msg, mtu)) {
 705                         kfree_skb(__skb_dequeue(list));
 706                         link->stats.sent_bundled++;
 707                         continue;
 708                 }
 709                 if (tipc_msg_make_bundle(&bskb, msg, mtu, link->addr)) {
 710                         kfree_skb(__skb_dequeue(list));
 711                         __skb_queue_tail(backlogq, bskb);
 712                         link->backlog[msg_importance(buf_msg(bskb))].len++;
 713                         link->stats.sent_bundled++;
 714                         link->stats.sent_bundles++;
 715                         continue;
 716                 }
 717                 link->backlog[imp].len += skb_queue_len(list);
 718                 skb_queue_splice_tail_init(list, backlogq);
 719         }
 720         link->snd_nxt = seqno;
 721         return 0;
 722 }
 723
 724 /**
 725  * tipc_link_xmit(): enqueue buffer list according to queue situation
 726  * @link: link to use
 727  * @list: chain of buffers containing message
 728  * @xmitq: returned list of packets to be sent by caller
 729  *
 730  * Consumes the buffer chain, except when returning -ELINKCONG,
 731  * since the caller then may want to make more send attempts.
 732  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 733  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 734  */
 735 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
 736                    struct sk_buff_head *xmitq)
 737 {
 738         struct tipc_msg *hdr = buf_msg(skb_peek(list));
 739         unsigned int maxwin = l->window;
 740         unsigned int i, imp = msg_importance(hdr);
 741         unsigned int mtu = l->mtu;
 742         u16 ack = l->rcv_nxt - 1;
 743         u16 seqno = l->snd_nxt;
 744         u16 bc_last_in = l->owner->bclink.last_in;
 745         struct sk_buff_head *transmq = &l->transmq;
 746         struct sk_buff_head *backlogq = &l->backlogq;
 747         struct sk_buff *skb, *_skb, *bskb;
 748
 749         /* Match msg importance against this and all higher backlog limits: */
 750         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 751                 if (unlikely(l->backlog[i].len >= l->backlog[i].limit))
 752                         return link_schedule_user(l, list);
 753         }
 754         if (unlikely(msg_size(hdr) > mtu))
 755                 return -EMSGSIZE;
 756
 757         /* Prepare each packet for sending, and add to relevant queue: */
 758         while (skb_queue_len(list)) {
 759                 skb = skb_peek(list);
 760                 hdr = buf_msg(skb);
 761                 msg_set_seqno(hdr, seqno);
 762                 msg_set_ack(hdr, ack);
 763                 msg_set_bcast_ack(hdr, bc_last_in);
 764
 765                 if (likely(skb_queue_len(transmq) < maxwin)) {
 766                         _skb = skb_clone(skb, GFP_ATOMIC);
 767                         if (!_skb)
 768                                 return -ENOBUFS;
 769                         __skb_dequeue(list);
 770                         __skb_queue_tail(transmq, skb);
 771                         __skb_queue_tail(xmitq, _skb);
 772                         l->rcv_unacked = 0;
 773                         seqno++;
 774                         continue;
 775                 }
 776                 if (tipc_msg_bundle(skb_peek_tail(backlogq), hdr, mtu)) {
 777                         kfree_skb(__skb_dequeue(list));
 778                         l->stats.sent_bundled++;
 779                         continue;
 780                 }
 781                 if (tipc_msg_make_bundle(&bskb, hdr, mtu, l->addr)) {
 782                         kfree_skb(__skb_dequeue(list));
 783                         __skb_queue_tail(backlogq, bskb);
 784                         l->backlog[msg_importance(buf_msg(bskb))].len++;
 785                         l->stats.sent_bundled++;
 786                         l->stats.sent_bundles++;
 787                         continue;
 788                 }
 789                 l->backlog[imp].len += skb_queue_len(list);
 790                 skb_queue_splice_tail_init(list, backlogq);
 791         }
 792         l->snd_nxt = seqno;
 793         return 0;
 794 }
 795
 796 static void skb2list(struct sk_buff *skb, struct sk_buff_head *list)
 797 {
 798         skb_queue_head_init(list);
 799         __skb_queue_tail(list, skb);
 800 }
 801
 802 static int __tipc_link_xmit_skb(struct tipc_link *link, struct sk_buff *skb)
 803 {
 804         struct sk_buff_head head;
 805
 806         skb2list(skb, &head);
 807         return __tipc_link_xmit(link->owner->net, link, &head);
 808 }
 809
 810 /*
 811  * tipc_link_sync_xmit - synchronize broadcast link endpoints.
 812  *
 813  * Give a newly added peer node the sequence number where it should
 814  * start receiving and acking broadcast packets.
 815  *
 816  * Called with node locked
 817  */
 818 static void tipc_link_sync_xmit(struct tipc_link *link)
 819 {
 820         struct sk_buff *skb;
 821         struct tipc_msg *msg;
 822
 823         skb = tipc_buf_acquire(INT_H_SIZE);
 824         if (!skb)
 825                 return;
 826
 827         msg = buf_msg(skb);
 828         tipc_msg_init(link_own_addr(link), msg, BCAST_PROTOCOL, STATE_MSG,
 829                       INT_H_SIZE, link->addr);
 830         msg_set_last_bcast(msg, link->owner->bclink.acked);
 831         __tipc_link_xmit_skb(link, skb);
 832 }
 833
 834 /*
 835  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
 836  * Receive the sequence number where we should start receiving and
 837  * acking broadcast packets from a newly added peer node, and open
 838  * up for reception of such packets.
 839  *
 840  * Called with node locked
 841  */
 842 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
 843 {
 844         struct tipc_msg *msg = buf_msg(buf);
 845
 846         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
 847         n->bclink.recv_permitted = true;
 848         kfree_skb(buf);
 849 }
 850
 851 /*
 852  * tipc_link_push_packets - push unsent packets to bearer
 853  *
 854  * Push out the unsent messages of a link where congestion
 855  * has abated. Node is locked.
 856  *
 857  * Called with node locked
 858  */
 859 void tipc_link_push_packets(struct tipc_link *link)
 860 {
 861         struct sk_buff *skb;
 862         struct tipc_msg *msg;
 863         u16 seqno = link->snd_nxt;
 864         u16 ack = mod(link->rcv_nxt - 1);
 865
 866         while (skb_queue_len(&link->transmq) < link->window) {
 867                 skb = __skb_dequeue(&link->backlogq);
 868                 if (!skb)
 869                         break;
 870                 msg = buf_msg(skb);
 871                 link->backlog[msg_importance(msg)].len--;
 872                 msg_set_ack(msg, ack);
 873                 msg_set_seqno(msg, seqno);
 874                 seqno = mod(seqno + 1);
 875                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
 876                 link->rcv_unacked = 0;
 877                 __skb_queue_tail(&link->transmq, skb);
 878                 tipc_bearer_send(link->owner->net, link->bearer_id,
 879                                  skb, &link->media_addr);
 880         }
 881         link->snd_nxt = seqno;
 882 }
 883
 884 void tipc_link_reset_all(struct tipc_node *node)
 885 {
 886         char addr_string[16];
 887         u32 i;
 888
 889         tipc_node_lock(node);
 890
 891         pr_warn("Resetting all links to %s\n",
 892                 tipc_addr_string_fill(addr_string, node->addr));
 893
 894         for (i = 0; i < MAX_BEARERS; i++) {
 895                 if (node->links[i].link) {
 896                         link_print(node->links[i].link, "Resetting link\n");
 897                         tipc_link_reset(node->links[i].link);
 898                 }
 899         }
 900
 901         tipc_node_unlock(node);
 902 }
 903
 904 static void link_retransmit_failure(struct tipc_link *l_ptr,
 905                                     struct sk_buff *buf)
 906 {
 907         struct tipc_msg *msg = buf_msg(buf);
 908         struct net *net = l_ptr->owner->net;
 909
 910         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
 911
 912         if (l_ptr->addr) {
 913                 /* Handle failure on standard link */
 914                 link_print(l_ptr, "Resetting link\n");
 915                 tipc_link_reset(l_ptr);
 916
 917         } else {
 918                 /* Handle failure on broadcast link */
 919                 struct tipc_node *n_ptr;
 920                 char addr_string[16];
 921
 922                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
 923                 pr_cont("Outstanding acks: %lu\n",
 924                         (unsigned long) TIPC_SKB_CB(buf)->handle);
 925
 926                 n_ptr = tipc_bclink_retransmit_to(net);
 927
 928                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 929                 pr_info("Broadcast link info for %s\n", addr_string);
 930                 pr_info("Reception permitted: %d,  Acked: %u\n",
 931                         n_ptr->bclink.recv_permitted,
 932                         n_ptr->bclink.acked);
 933                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
 934                         n_ptr->bclink.last_in,
 935                         n_ptr->bclink.oos_state,
 936                         n_ptr->bclink.last_sent);
 937
 938                 n_ptr->action_flags |= TIPC_BCAST_RESET;
 939                 l_ptr->stale_count = 0;
 940         }
 941 }
 942
 943 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
 944                           u32 retransmits)
 945 {
 946         struct tipc_msg *msg;
 947
 948         if (!skb)
 949                 return;
 950
 951         msg = buf_msg(skb);
 952
 953         /* Detect repeated retransmit failures */
 954         if (l_ptr->last_retransm == msg_seqno(msg)) {
 955                 if (++l_ptr->stale_count > 100) {
 956                         link_retransmit_failure(l_ptr, skb);
 957                         return;
 958                 }
 959         } else {
 960                 l_ptr->last_retransm = msg_seqno(msg);
 961                 l_ptr->stale_count = 1;
 962         }
 963
 964         skb_queue_walk_from(&l_ptr->transmq, skb) {
 965                 if (!retransmits)
 966                         break;
 967                 msg = buf_msg(skb);
 968                 msg_set_ack(msg, mod(l_ptr->rcv_nxt - 1));
 969                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
 970                 tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, skb,
 971                                  &l_ptr->media_addr);
 972                 retransmits--;
 973                 l_ptr->stats.retransmitted++;
 974         }
 975 }
 976
 977 /* link_synch(): check if all packets arrived before the synch
 978  *               point have been consumed
 979  * Returns true if the parallel links are synched, otherwise false
 980  */
 981 static bool link_synch(struct tipc_link *l)
 982 {
 983         unsigned int post_synch;
 984         struct tipc_link *pl;
 985
 986         pl  = tipc_parallel_link(l);
 987         if (pl == l)
 988                 goto synched;
 989
 990         /* Was last pre-synch packet added to input queue ? */
 991         if (less_eq(pl->rcv_nxt, l->synch_point))
 992                 return false;
 993
 994         /* Is it still in the input queue ? */
 995         post_synch = mod(pl->rcv_nxt - l->synch_point) - 1;
 996         if (skb_queue_len(pl->inputq) > post_synch)
 997                 return false;
 998 synched:
 999         l->exec_mode = TIPC_LINK_OPEN;
1000         return true;
1001 }
1002
1003 static void link_retrieve_defq(struct tipc_link *link,
1004                                struct sk_buff_head *list)
1005 {
1006         u16 seq_no;
1007
1008         if (skb_queue_empty(&link->deferdq))
1009                 return;
1010
1011         seq_no = buf_seqno(skb_peek(&link->deferdq));
1012         if (seq_no == link->rcv_nxt)
1013                 skb_queue_splice_tail_init(&link->deferdq, list);
1014 }
1015
1016 /**
1017  * tipc_rcv - process TIPC packets/messages arriving from off-node
1018  * @net: the applicable net namespace
1019  * @skb: TIPC packet
1020  * @b_ptr: pointer to bearer message arrived on
1021  *
1022  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1023  * structure (i.e. cannot be NULL), but bearer can be inactive.
1024  */
1025 void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b_ptr)
1026 {
1027         struct tipc_net *tn = net_generic(net, tipc_net_id);
1028         struct sk_buff_head head;
1029         struct tipc_node *n_ptr;
1030         struct tipc_link *l_ptr;
1031         struct sk_buff *skb1, *tmp;
1032         struct tipc_msg *msg;
1033         u16 seq_no;
1034         u16 ackd;
1035         u32 released;
1036
1037         skb2list(skb, &head);
1038
1039         while ((skb = __skb_dequeue(&head))) {
1040                 /* Ensure message is well-formed */
1041                 if (unlikely(!tipc_msg_validate(skb)))
1042                         goto discard;
1043
1044                 /* Handle arrival of a non-unicast link message */
1045                 msg = buf_msg(skb);
1046                 if (unlikely(msg_non_seq(msg))) {
1047                         if (msg_user(msg) ==  LINK_CONFIG)
1048                                 tipc_disc_rcv(net, skb, b_ptr);
1049                         else
1050                                 tipc_bclink_rcv(net, skb);
1051                         continue;
1052                 }
1053
1054                 /* Discard unicast link messages destined for another node */
1055                 if (unlikely(!msg_short(msg) &&
1056                              (msg_destnode(msg) != tn->own_addr)))
1057                         goto discard;
1058
1059                 /* Locate neighboring node that sent message */
1060                 n_ptr = tipc_node_find(net, msg_prevnode(msg));
1061                 if (unlikely(!n_ptr))
1062                         goto discard;
1063
1064                 tipc_node_lock(n_ptr);
1065                 /* Locate unicast link endpoint that should handle message */
1066                 l_ptr = n_ptr->links[b_ptr->identity].link;
1067                 if (unlikely(!l_ptr))
1068                         goto unlock;
1069
1070                 /* Verify that communication with node is currently allowed */
1071                 if ((n_ptr->action_flags & TIPC_WAIT_PEER_LINKS_DOWN) &&
1072                     msg_user(msg) == LINK_PROTOCOL &&
1073                     (msg_type(msg) == RESET_MSG ||
1074                     msg_type(msg) == ACTIVATE_MSG) &&
1075                     !msg_redundant_link(msg))
1076                         n_ptr->action_flags &= ~TIPC_WAIT_PEER_LINKS_DOWN;
1077
1078                 if (tipc_node_blocked(n_ptr))
1079                         goto unlock;
1080
1081                 /* Validate message sequence number info */
1082                 seq_no = msg_seqno(msg);
1083                 ackd = msg_ack(msg);
1084
1085                 /* Release acked messages */
1086                 if (unlikely(n_ptr->bclink.acked != msg_bcast_ack(msg)))
1087                         tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1088
1089                 released = 0;
1090                 skb_queue_walk_safe(&l_ptr->transmq, skb1, tmp) {
1091                         if (more(buf_seqno(skb1), ackd))
1092                                 break;
1093                          __skb_unlink(skb1, &l_ptr->transmq);
1094                          kfree_skb(skb1);
1095                          released = 1;
1096                 }
1097
1098                 /* Try sending any messages link endpoint has pending */
1099                 if (unlikely(skb_queue_len(&l_ptr->backlogq)))
1100                         tipc_link_push_packets(l_ptr);
1101
1102                 if (released && !skb_queue_empty(&l_ptr->wakeupq))
1103                         link_prepare_wakeup(l_ptr);
1104
1105                 /* Process the incoming packet */
1106                 if (unlikely(!link_working(l_ptr))) {
1107                         if (msg_user(msg) == LINK_PROTOCOL) {
1108                                 tipc_link_proto_rcv(l_ptr, skb);
1109                                 link_retrieve_defq(l_ptr, &head);
1110                                 skb = NULL;
1111                                 goto unlock;
1112                         }
1113
1114                         /* Traffic message. Conditionally activate link */
1115                         link_state_event(l_ptr, TRAFFIC_EVT);
1116
1117                         if (link_working(l_ptr)) {
1118                                 /* Re-insert buffer in front of queue */
1119                                 __skb_queue_head(&head, skb);
1120                                 skb = NULL;
1121                                 goto unlock;
1122                         }
1123                         goto unlock;
1124                 }
1125
1126                 /* Link is now in state TIPC_LINK_WORKING */
1127                 if (unlikely(seq_no != l_ptr->rcv_nxt)) {
1128                         link_handle_out_of_seq_msg(l_ptr, skb);
1129                         link_retrieve_defq(l_ptr, &head);
1130                         skb = NULL;
1131                         goto unlock;
1132                 }
1133                 l_ptr->silent_intv_cnt = 0;
1134
1135                 /* Synchronize with parallel link if applicable */
1136                 if (unlikely((l_ptr->exec_mode == TIPC_LINK_TUNNEL) &&
1137                              !msg_dup(msg))) {
1138                         if (!link_synch(l_ptr))
1139                                 goto unlock;
1140                 }
1141                 l_ptr->rcv_nxt++;
1142                 if (unlikely(!skb_queue_empty(&l_ptr->deferdq)))
1143                         link_retrieve_defq(l_ptr, &head);
1144                 if (unlikely(++l_ptr->rcv_unacked >= TIPC_MIN_LINK_WIN)) {
1145                         l_ptr->stats.sent_acks++;
1146                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0);
1147                 }
1148                 tipc_link_input(l_ptr, skb);
1149                 skb = NULL;
1150 unlock:
1151                 tipc_node_unlock(n_ptr);
1152                 tipc_node_put(n_ptr);
1153 discard:
1154                 if (unlikely(skb))
1155                         kfree_skb(skb);
1156         }
1157 }
1158
1159 /* tipc_data_input - deliver data and name distr msgs to upper layer
1160  *
1161  * Consumes buffer if message is of right type
1162  * Node lock must be held
1163  */
1164 static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb)
1165 {
1166         struct tipc_node *node = link->owner;
1167         struct tipc_msg *msg = buf_msg(skb);
1168         u32 dport = msg_destport(msg);
1169
1170         switch (msg_user(msg)) {
1171         case TIPC_LOW_IMPORTANCE:
1172         case TIPC_MEDIUM_IMPORTANCE:
1173         case TIPC_HIGH_IMPORTANCE:
1174         case TIPC_CRITICAL_IMPORTANCE:
1175         case CONN_MANAGER:
1176                 if (tipc_skb_queue_tail(link->inputq, skb, dport)) {
1177                         node->inputq = link->inputq;
1178                         node->action_flags |= TIPC_MSG_EVT;
1179                 }
1180                 return true;
1181         case NAME_DISTRIBUTOR:
1182                 node->bclink.recv_permitted = true;
1183                 node->namedq = link->namedq;
1184                 skb_queue_tail(link->namedq, skb);
1185                 if (skb_queue_len(link->namedq) == 1)
1186                         node->action_flags |= TIPC_NAMED_MSG_EVT;
1187                 return true;
1188         case MSG_BUNDLER:
1189         case TUNNEL_PROTOCOL:
1190         case MSG_FRAGMENTER:
1191         case BCAST_PROTOCOL:
1192                 return false;
1193         default:
1194                 pr_warn("Dropping received illegal msg type\n");
1195                 kfree_skb(skb);
1196                 return false;
1197         };
1198 }
1199
1200 /* tipc_link_input - process packet that has passed link protocol check
1201  *
1202  * Consumes buffer
1203  * Node lock must be held
1204  */
1205 static void tipc_link_input(struct tipc_link *link, struct sk_buff *skb)
1206 {
1207         struct tipc_node *node = link->owner;
1208         struct tipc_msg *msg = buf_msg(skb);
1209         struct sk_buff *iskb;
1210         int pos = 0;
1211
1212         if (likely(tipc_data_input(link, skb)))
1213                 return;
1214
1215         switch (msg_user(msg)) {
1216         case TUNNEL_PROTOCOL:
1217                 if (msg_dup(msg)) {
1218                         link->exec_mode = TIPC_LINK_TUNNEL;
1219                         link->synch_point = msg_seqno(msg_get_wrapped(msg));
1220                         kfree_skb(skb);
1221                         break;
1222                 }
1223                 if (!tipc_link_failover_rcv(link, &skb))
1224                         break;
1225                 if (msg_user(buf_msg(skb)) != MSG_BUNDLER) {
1226                         tipc_data_input(link, skb);
1227                         break;
1228                 }
1229         case MSG_BUNDLER:
1230                 link->stats.recv_bundles++;
1231                 link->stats.recv_bundled += msg_msgcnt(msg);
1232
1233                 while (tipc_msg_extract(skb, &iskb, &pos))
1234                         tipc_data_input(link, iskb);
1235                 break;
1236         case MSG_FRAGMENTER:
1237                 link->stats.recv_fragments++;
1238                 if (tipc_buf_append(&link->reasm_buf, &skb)) {
1239                         link->stats.recv_fragmented++;
1240                         tipc_data_input(link, skb);
1241                 } else if (!link->reasm_buf) {
1242                         tipc_link_reset(link);
1243                 }
1244                 break;
1245         case BCAST_PROTOCOL:
1246                 tipc_link_sync_rcv(node, skb);
1247                 break;
1248         default:
1249                 break;
1250         };
1251 }
1252
1253 /**
1254  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1255  *
1256  * Returns increase in queue length (i.e. 0 or 1)
1257  */
1258 u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
1259 {
1260         struct sk_buff *skb1;
1261         u16 seq_no = buf_seqno(skb);
1262
1263         /* Empty queue ? */
1264         if (skb_queue_empty(list)) {
1265                 __skb_queue_tail(list, skb);
1266                 return 1;
1267         }
1268
1269         /* Last ? */
1270         if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
1271                 __skb_queue_tail(list, skb);
1272                 return 1;
1273         }
1274
1275         /* Locate insertion point in queue, then insert; discard if duplicate */
1276         skb_queue_walk(list, skb1) {
1277                 u16 curr_seqno = buf_seqno(skb1);
1278
1279                 if (seq_no == curr_seqno) {
1280                         kfree_skb(skb);
1281                         return 0;
1282                 }
1283
1284                 if (less(seq_no, curr_seqno))
1285                         break;
1286         }
1287
1288         __skb_queue_before(list, skb1, skb);
1289         return 1;
1290 }
1291
1292 /*
1293  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1294  */
1295 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1296                                        struct sk_buff *buf)
1297 {
1298         u32 seq_no = buf_seqno(buf);
1299
1300         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1301                 tipc_link_proto_rcv(l_ptr, buf);
1302                 return;
1303         }
1304
1305         /* Record OOS packet arrival */
1306         l_ptr->silent_intv_cnt = 0;
1307
1308         /*
1309          * Discard packet if a duplicate; otherwise add it to deferred queue
1310          * and notify peer of gap as per protocol specification
1311          */
1312         if (less(seq_no, l_ptr->rcv_nxt)) {
1313                 l_ptr->stats.duplicates++;
1314                 kfree_skb(buf);
1315                 return;
1316         }
1317
1318         if (tipc_link_defer_pkt(&l_ptr->deferdq, buf)) {
1319                 l_ptr->stats.deferred_recv++;
1320                 if ((skb_queue_len(&l_ptr->deferdq) % TIPC_MIN_LINK_WIN) == 1)
1321                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0);
1322         } else {
1323                 l_ptr->stats.duplicates++;
1324         }
1325 }
1326
1327 /*
1328  * Send protocol message to the other endpoint.
1329  */
1330 void tipc_link_proto_xmit(struct tipc_link *l, u32 msg_typ, int probe_msg,
1331                           u32 gap, u32 tolerance, u32 priority)
1332 {
1333         struct sk_buff *skb = NULL;
1334         struct sk_buff_head xmitq;
1335
1336         __skb_queue_head_init(&xmitq);
1337         tipc_link_build_proto_msg(l, msg_typ, probe_msg, gap,
1338                                   tolerance, priority, &xmitq);
1339         skb = __skb_dequeue(&xmitq);
1340         if (!skb)
1341                 return;
1342         tipc_bearer_send(l->owner->net, l->bearer_id, skb, &l->media_addr);
1343         l->rcv_unacked = 0;
1344         kfree_skb(skb);
1345 }
1346
1347 /*
1348  * Receive protocol message :
1349  * Note that network plane id propagates through the network, and may
1350  * change at any time. The node with lowest address rules
1351  */
1352 static void tipc_link_proto_rcv(struct tipc_link *l_ptr,
1353                                 struct sk_buff *buf)
1354 {
1355         u32 rec_gap = 0;
1356         u32 msg_tol;
1357         struct tipc_msg *msg = buf_msg(buf);
1358
1359         if (l_ptr->exec_mode == TIPC_LINK_BLOCKED)
1360                 goto exit;
1361
1362         if (l_ptr->net_plane != msg_net_plane(msg))
1363                 if (link_own_addr(l_ptr) > msg_prevnode(msg))
1364                         l_ptr->net_plane = msg_net_plane(msg);
1365
1366         switch (msg_type(msg)) {
1367
1368         case RESET_MSG:
1369                 if (!link_probing(l_ptr) &&
1370                     (l_ptr->peer_session != WILDCARD_SESSION)) {
1371                         if (less_eq(msg_session(msg), l_ptr->peer_session))
1372                                 break; /* duplicate or old reset: ignore */
1373                 }
1374
1375                 if (!msg_redundant_link(msg) && (link_working(l_ptr) ||
1376                                                  link_probing(l_ptr))) {
1377                         /* peer has lost contact -- don't allow peer's links
1378                          * to reactivate before we recognize loss & clean up
1379                          */
1380                         l_ptr->owner->action_flags |= TIPC_WAIT_OWN_LINKS_DOWN;
1381                 }
1382
1383                 link_state_event(l_ptr, RESET_MSG);
1384
1385                 /* fall thru' */
1386         case ACTIVATE_MSG:
1387                 /* Update link settings according other endpoint's values */
1388                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
1389
1390                 msg_tol = msg_link_tolerance(msg);
1391                 if (msg_tol > l_ptr->tolerance)
1392                         l_ptr->tolerance = msg_tol;
1393
1394                 if (msg_linkprio(msg) > l_ptr->priority)
1395                         l_ptr->priority = msg_linkprio(msg);
1396
1397                 if (l_ptr->mtu > msg_max_pkt(msg))
1398                         l_ptr->mtu = msg_max_pkt(msg);
1399
1400                 /* Synchronize broadcast link info, if not done previously */
1401                 if (!tipc_node_is_up(l_ptr->owner)) {
1402                         l_ptr->owner->bclink.last_sent =
1403                                 l_ptr->owner->bclink.last_in =
1404                                 msg_last_bcast(msg);
1405                         l_ptr->owner->bclink.oos_state = 0;
1406                 }
1407
1408                 l_ptr->peer_session = msg_session(msg);
1409                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
1410
1411                 if (msg_type(msg) == ACTIVATE_MSG)
1412                         link_state_event(l_ptr, ACTIVATE_MSG);
1413                 break;
1414         case STATE_MSG:
1415
1416                 msg_tol = msg_link_tolerance(msg);
1417                 if (msg_tol)
1418                         l_ptr->tolerance = msg_tol;
1419
1420                 if (msg_linkprio(msg) &&
1421                     (msg_linkprio(msg) != l_ptr->priority)) {
1422                         pr_debug("%s<%s>, priority change %u->%u\n",
1423                                  link_rst_msg, l_ptr->name,
1424                                  l_ptr->priority, msg_linkprio(msg));
1425                         l_ptr->priority = msg_linkprio(msg);
1426                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
1427                         break;
1428                 }
1429
1430                 /* Record reception; force mismatch at next timeout: */
1431                 l_ptr->silent_intv_cnt = 0;
1432
1433                 link_state_event(l_ptr, TRAFFIC_EVT);
1434                 l_ptr->stats.recv_states++;
1435                 if (link_resetting(l_ptr))
1436                         break;
1437
1438                 if (less_eq(l_ptr->rcv_nxt, msg_next_sent(msg)))
1439                         rec_gap = mod(msg_next_sent(msg) - l_ptr->rcv_nxt);
1440
1441                 if (msg_probe(msg))
1442                         l_ptr->stats.recv_probes++;
1443
1444                 /* Protocol message before retransmits, reduce loss risk */
1445                 if (l_ptr->owner->bclink.recv_permitted)
1446                         tipc_bclink_update_link_state(l_ptr->owner,
1447                                                       msg_last_bcast(msg));
1448
1449                 if (rec_gap || (msg_probe(msg))) {
1450                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0,
1451                                              rec_gap, 0, 0);
1452                 }
1453                 if (msg_seq_gap(msg)) {
1454                         l_ptr->stats.recv_nacks++;
1455                         tipc_link_retransmit(l_ptr, skb_peek(&l_ptr->transmq),
1456                                              msg_seq_gap(msg));
1457                 }
1458                 break;
1459         }
1460 exit:
1461         kfree_skb(buf);
1462 }
1463
1464 /* tipc_link_build_proto_msg: prepare link protocol message for transmission
1465  */
1466 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1467                                       u16 rcvgap, int tolerance, int priority,
1468                                       struct sk_buff_head *xmitq)
1469 {
1470         struct sk_buff *skb = NULL;
1471         struct tipc_msg *hdr = l->pmsg;
1472         u16 snd_nxt = l->snd_nxt;
1473         u16 rcv_nxt = l->rcv_nxt;
1474         u16 rcv_last = rcv_nxt - 1;
1475         int node_up = l->owner->bclink.recv_permitted;
1476
1477         /* Don't send protocol message during reset or link failover */
1478         if (l->exec_mode == TIPC_LINK_BLOCKED)
1479                 return;
1480
1481         /* Abort non-RESET send if communication with node is prohibited */
1482         if ((tipc_node_blocked(l->owner)) && (mtyp != RESET_MSG))
1483                 return;
1484
1485         msg_set_type(hdr, mtyp);
1486         msg_set_net_plane(hdr, l->net_plane);
1487         msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
1488         msg_set_last_bcast(hdr, tipc_bclink_get_last_sent(l->owner->net));
1489         msg_set_link_tolerance(hdr, tolerance);
1490         msg_set_linkprio(hdr, priority);
1491         msg_set_redundant_link(hdr, node_up);
1492         msg_set_seq_gap(hdr, 0);
1493
1494         /* Compatibility: created msg must not be in sequence with pkt flow */
1495         msg_set_seqno(hdr, snd_nxt + U16_MAX / 2);
1496
1497         if (mtyp == STATE_MSG) {
1498                 if (!tipc_link_is_up(l))
1499                         return;
1500                 msg_set_next_sent(hdr, snd_nxt);
1501
1502                 /* Override rcvgap if there are packets in deferred queue */
1503                 if (!skb_queue_empty(&l->deferdq))
1504                         rcvgap = buf_seqno(skb_peek(&l->deferdq)) - rcv_nxt;
1505                 if (rcvgap) {
1506                         msg_set_seq_gap(hdr, rcvgap);
1507                         l->stats.sent_nacks++;
1508                 }
1509                 msg_set_ack(hdr, rcv_last);
1510                 msg_set_probe(hdr, probe);
1511                 if (probe)
1512                         l->stats.sent_probes++;
1513                 l->stats.sent_states++;
1514         } else {
1515                 /* RESET_MSG or ACTIVATE_MSG */
1516                 msg_set_max_pkt(hdr, l->advertised_mtu);
1517                 msg_set_ack(hdr, l->failover_checkpt - 1);
1518                 msg_set_next_sent(hdr, 1);
1519         }
1520         skb = tipc_buf_acquire(msg_size(hdr));
1521         if (!skb)
1522                 return;
1523         skb_copy_to_linear_data(skb, hdr, msg_size(hdr));
1524         skb->priority = TC_PRIO_CONTROL;
1525         __skb_queue_head(xmitq, skb);
1526 }
1527
1528 /* tipc_link_tunnel_xmit(): Tunnel one packet via a link belonging to
1529  * a different bearer. Owner node is locked.
1530  */
1531 static void tipc_link_tunnel_xmit(struct tipc_link *l_ptr,
1532                                   struct tipc_msg *tunnel_hdr,
1533                                   struct tipc_msg *msg,
1534                                   u32 selector)
1535 {
1536         struct tipc_link *tunnel;
1537         struct sk_buff *skb;
1538         u32 length = msg_size(msg);
1539
1540         tunnel = node_active_link(l_ptr->owner, selector & 1);
1541         if (!tipc_link_is_up(tunnel)) {
1542                 pr_warn("%stunnel link no longer available\n", link_co_err);
1543                 return;
1544         }
1545         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
1546         skb = tipc_buf_acquire(length + INT_H_SIZE);
1547         if (!skb) {
1548                 pr_warn("%sunable to send tunnel msg\n", link_co_err);
1549                 return;
1550         }
1551         skb_copy_to_linear_data(skb, tunnel_hdr, INT_H_SIZE);
1552         skb_copy_to_linear_data_offset(skb, INT_H_SIZE, msg, length);
1553         __tipc_link_xmit_skb(tunnel, skb);
1554 }
1555
1556
1557 /* tipc_link_failover_send_queue(): A link has gone down, but a second
1558  * link is still active. We can do failover. Tunnel the failing link's
1559  * whole send queue via the remaining link. This way, we don't lose
1560  * any packets, and sequence order is preserved for subsequent traffic
1561  * sent over the remaining link. Owner node is locked.
1562  */
1563 void tipc_link_failover_send_queue(struct tipc_link *l_ptr)
1564 {
1565         int msgcount;
1566         struct tipc_link *tunnel = node_active_link(l_ptr->owner, 0);
1567         struct tipc_msg tunnel_hdr;
1568         struct sk_buff *skb;
1569         int split_bundles;
1570
1571         if (!tunnel)
1572                 return;
1573
1574         tipc_msg_init(link_own_addr(l_ptr), &tunnel_hdr, TUNNEL_PROTOCOL,
1575                       FAILOVER_MSG, INT_H_SIZE, l_ptr->addr);
1576
1577         skb_queue_walk(&l_ptr->backlogq, skb) {
1578                 msg_set_seqno(buf_msg(skb), l_ptr->snd_nxt);
1579                 l_ptr->snd_nxt = mod(l_ptr->snd_nxt + 1);
1580         }
1581         skb_queue_splice_tail_init(&l_ptr->backlogq, &l_ptr->transmq);
1582         tipc_link_purge_backlog(l_ptr);
1583         msgcount = skb_queue_len(&l_ptr->transmq);
1584         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
1585         msg_set_msgcnt(&tunnel_hdr, msgcount);
1586
1587         if (skb_queue_empty(&l_ptr->transmq)) {
1588                 skb = tipc_buf_acquire(INT_H_SIZE);
1589                 if (skb) {
1590                         skb_copy_to_linear_data(skb, &tunnel_hdr, INT_H_SIZE);
1591                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
1592                         __tipc_link_xmit_skb(tunnel, skb);
1593                 } else {
1594                         pr_warn("%sunable to send changeover msg\n",
1595                                 link_co_err);
1596                 }
1597                 return;
1598         }
1599
1600         split_bundles = (node_active_link(l_ptr->owner, 0) !=
1601                          node_active_link(l_ptr->owner, 0));
1602
1603         skb_queue_walk(&l_ptr->transmq, skb) {
1604                 struct tipc_msg *msg = buf_msg(skb);
1605
1606                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
1607                         struct tipc_msg *m = msg_get_wrapped(msg);
1608                         unchar *pos = (unchar *)m;
1609
1610                         msgcount = msg_msgcnt(msg);
1611                         while (msgcount--) {
1612                                 msg_set_seqno(m, msg_seqno(msg));
1613                                 tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, m,
1614                                                       msg_link_selector(m));
1615                                 pos += align(msg_size(m));
1616                                 m = (struct tipc_msg *)pos;
1617                         }
1618                 } else {
1619                         tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, msg,
1620                                               msg_link_selector(msg));
1621                 }
1622         }
1623 }
1624
1625 /* tipc_link_dup_queue_xmit(): A second link has become active. Tunnel a
1626  * duplicate of the first link's send queue via the new link. This way, we
1627  * are guaranteed that currently queued packets from a socket are delivered
1628  * before future traffic from the same socket, even if this is using the
1629  * new link. The last arriving copy of each duplicate packet is dropped at
1630  * the receiving end by the regular protocol check, so packet cardinality
1631  * and sequence order is preserved per sender/receiver socket pair.
1632  * Owner node is locked.
1633  */
1634 void tipc_link_dup_queue_xmit(struct tipc_link *link,
1635                               struct tipc_link *tnl)
1636 {
1637         struct sk_buff *skb;
1638         struct tipc_msg tnl_hdr;
1639         struct sk_buff_head *queue = &link->transmq;
1640         int mcnt;
1641         u16 seqno;
1642
1643         tipc_msg_init(link_own_addr(link), &tnl_hdr, TUNNEL_PROTOCOL,
1644                       SYNCH_MSG, INT_H_SIZE, link->addr);
1645         mcnt = skb_queue_len(&link->transmq) + skb_queue_len(&link->backlogq);
1646         msg_set_msgcnt(&tnl_hdr, mcnt);
1647         msg_set_bearer_id(&tnl_hdr, link->peer_bearer_id);
1648
1649 tunnel_queue:
1650         skb_queue_walk(queue, skb) {
1651                 struct sk_buff *outskb;
1652                 struct tipc_msg *msg = buf_msg(skb);
1653                 u32 len = msg_size(msg);
1654
1655                 msg_set_ack(msg, mod(link->rcv_nxt - 1));
1656                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
1657                 msg_set_size(&tnl_hdr, len + INT_H_SIZE);
1658                 outskb = tipc_buf_acquire(len + INT_H_SIZE);
1659                 if (outskb == NULL) {
1660                         pr_warn("%sunable to send duplicate msg\n",
1661                                 link_co_err);
1662                         return;
1663                 }
1664                 skb_copy_to_linear_data(outskb, &tnl_hdr, INT_H_SIZE);
1665                 skb_copy_to_linear_data_offset(outskb, INT_H_SIZE,
1666                                                skb->data, len);
1667                 __tipc_link_xmit_skb(tnl, outskb);
1668                 if (!tipc_link_is_up(link))
1669                         return;
1670         }
1671         if (queue == &link->backlogq)
1672                 return;
1673         seqno = link->snd_nxt;
1674         skb_queue_walk(&link->backlogq, skb) {
1675                 msg_set_seqno(buf_msg(skb), seqno);
1676                 seqno = mod(seqno + 1);
1677         }
1678         queue = &link->backlogq;
1679         goto tunnel_queue;
1680 }
1681
1682 /*  tipc_link_failover_rcv(): Receive a tunnelled FAILOVER_MSG packet
1683  *  Owner node is locked.
1684  */
1685 static bool tipc_link_failover_rcv(struct tipc_link *link,
1686                                    struct sk_buff **skb)
1687 {
1688         struct tipc_msg *msg = buf_msg(*skb);
1689         struct sk_buff *iskb = NULL;
1690         struct tipc_link *pl = NULL;
1691         int bearer_id = msg_bearer_id(msg);
1692         int pos = 0;
1693
1694         if (msg_type(msg) != FAILOVER_MSG) {
1695                 pr_warn("%sunknown tunnel pkt received\n", link_co_err);
1696                 goto exit;
1697         }
1698         if (bearer_id >= MAX_BEARERS)
1699                 goto exit;
1700
1701         if (bearer_id == link->bearer_id)
1702                 goto exit;
1703
1704         pl = link->owner->links[bearer_id].link;
1705         if (pl && tipc_link_is_up(pl))
1706                 tipc_link_reset(pl);
1707
1708         if (link->failover_pkts == FIRST_FAILOVER)
1709                 link->failover_pkts = msg_msgcnt(msg);
1710
1711         /* Should we expect an inner packet? */
1712         if (!link->failover_pkts)
1713                 goto exit;
1714
1715         if (!tipc_msg_extract(*skb, &iskb, &pos)) {
1716                 pr_warn("%sno inner failover pkt\n", link_co_err);
1717                 *skb = NULL;
1718                 goto exit;
1719         }
1720         link->failover_pkts--;
1721         *skb = NULL;
1722
1723         /* Was this packet already delivered? */
1724         if (less(buf_seqno(iskb), link->failover_checkpt)) {
1725                 kfree_skb(iskb);
1726                 iskb = NULL;
1727                 goto exit;
1728         }
1729         if (msg_user(buf_msg(iskb)) == MSG_FRAGMENTER) {
1730                 link->stats.recv_fragments++;
1731                 tipc_buf_append(&link->failover_skb, &iskb);
1732         }
1733 exit:
1734         if (!link->failover_pkts && pl)
1735                 pl->exec_mode = TIPC_LINK_OPEN;
1736         kfree_skb(*skb);
1737         *skb = iskb;
1738         return *skb;
1739 }
1740
1741 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1742 {
1743         int max_bulk = TIPC_MAX_PUBLICATIONS / (l->mtu / ITEM_SIZE);
1744
1745         l->window = win;
1746         l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
1747         l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
1748         l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
1749         l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
1750         l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1751 }
1752
1753 /* tipc_link_find_owner - locate owner node of link by link's name
1754  * @net: the applicable net namespace
1755  * @name: pointer to link name string
1756  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1757  *
1758  * Returns pointer to node owning the link, or 0 if no matching link is found.
1759  */
1760 static struct tipc_node *tipc_link_find_owner(struct net *net,
1761                                               const char *link_name,
1762                                               unsigned int *bearer_id)
1763 {
1764         struct tipc_net *tn = net_generic(net, tipc_net_id);
1765         struct tipc_link *l_ptr;
1766         struct tipc_node *n_ptr;
1767         struct tipc_node *found_node = NULL;
1768         int i;
1769
1770         *bearer_id = 0;
1771         rcu_read_lock();
1772         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
1773                 tipc_node_lock(n_ptr);
1774                 for (i = 0; i < MAX_BEARERS; i++) {
1775                         l_ptr = n_ptr->links[i].link;
1776                         if (l_ptr && !strcmp(l_ptr->name, link_name)) {
1777                                 *bearer_id = i;
1778                                 found_node = n_ptr;
1779                                 break;
1780                         }
1781                 }
1782                 tipc_node_unlock(n_ptr);
1783                 if (found_node)
1784                         break;
1785         }
1786         rcu_read_unlock();
1787
1788         return found_node;
1789 }
1790
1791 /**
1792  * link_reset_statistics - reset link statistics
1793  * @l_ptr: pointer to link
1794  */
1795 static void link_reset_statistics(struct tipc_link *l_ptr)
1796 {
1797         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
1798         l_ptr->stats.sent_info = l_ptr->snd_nxt;
1799         l_ptr->stats.recv_info = l_ptr->rcv_nxt;
1800 }
1801
1802 static void link_print(struct tipc_link *l_ptr, const char *str)
1803 {
1804         struct tipc_net *tn = net_generic(l_ptr->owner->net, tipc_net_id);
1805         struct tipc_bearer *b_ptr;
1806
1807         rcu_read_lock();
1808         b_ptr = rcu_dereference_rtnl(tn->bearer_list[l_ptr->bearer_id]);
1809         if (b_ptr)
1810                 pr_info("%s Link %x<%s>:", str, l_ptr->addr, b_ptr->name);
1811         rcu_read_unlock();
1812
1813         if (link_probing(l_ptr))
1814                 pr_cont(":P\n");
1815         else if (link_establishing(l_ptr))
1816                 pr_cont(":E\n");
1817         else if (link_resetting(l_ptr))
1818                 pr_cont(":R\n");
1819         else if (link_working(l_ptr))
1820                 pr_cont(":W\n");
1821         else
1822                 pr_cont("\n");
1823 }
1824
1825 /* Parse and validate nested (link) properties valid for media, bearer and link
1826  */
1827 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1828 {
1829         int err;
1830
1831         err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1832                                tipc_nl_prop_policy);
1833         if (err)
1834                 return err;
1835
1836         if (props[TIPC_NLA_PROP_PRIO]) {
1837                 u32 prio;
1838
1839                 prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1840                 if (prio > TIPC_MAX_LINK_PRI)
1841                         return -EINVAL;
1842         }
1843
1844         if (props[TIPC_NLA_PROP_TOL]) {
1845                 u32 tol;
1846
1847                 tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1848                 if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1849                         return -EINVAL;
1850         }
1851
1852         if (props[TIPC_NLA_PROP_WIN]) {
1853                 u32 win;
1854
1855                 win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1856                 if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1857                         return -EINVAL;
1858         }
1859
1860         return 0;
1861 }
1862
1863 int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
1864 {
1865         int err;
1866         int res = 0;
1867         int bearer_id;
1868         char *name;
1869         struct tipc_link *link;
1870         struct tipc_node *node;
1871         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1872         struct net *net = sock_net(skb->sk);
1873
1874         if (!info->attrs[TIPC_NLA_LINK])
1875                 return -EINVAL;
1876
1877         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1878                                info->attrs[TIPC_NLA_LINK],
1879                                tipc_nl_link_policy);
1880         if (err)
1881                 return err;
1882
1883         if (!attrs[TIPC_NLA_LINK_NAME])
1884                 return -EINVAL;
1885
1886         name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1887
1888         if (strcmp(name, tipc_bclink_name) == 0)
1889                 return tipc_nl_bc_link_set(net, attrs);
1890
1891         node = tipc_link_find_owner(net, name, &bearer_id);
1892         if (!node)
1893                 return -EINVAL;
1894
1895         tipc_node_lock(node);
1896
1897         link = node->links[bearer_id].link;
1898         if (!link) {
1899                 res = -EINVAL;
1900                 goto out;
1901         }
1902
1903         if (attrs[TIPC_NLA_LINK_PROP]) {
1904                 struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
1905
1906                 err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
1907                                               props);
1908                 if (err) {
1909                         res = err;
1910                         goto out;
1911                 }
1912
1913                 if (props[TIPC_NLA_PROP_TOL]) {
1914                         u32 tol;
1915
1916                         tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1917                         link->tolerance = tol;
1918                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0);
1919                 }
1920                 if (props[TIPC_NLA_PROP_PRIO]) {
1921                         u32 prio;
1922
1923                         prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1924                         link->priority = prio;
1925                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, 0, prio);
1926                 }
1927                 if (props[TIPC_NLA_PROP_WIN]) {
1928                         u32 win;
1929
1930                         win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1931                         tipc_link_set_queue_limits(link, win);
1932                 }
1933         }
1934
1935 out:
1936         tipc_node_unlock(node);
1937
1938         return res;
1939 }
1940
1941 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
1942 {
1943         int i;
1944         struct nlattr *stats;
1945
1946         struct nla_map {
1947                 u32 key;
1948                 u32 val;
1949         };
1950
1951         struct nla_map map[] = {
1952                 {TIPC_NLA_STATS_RX_INFO, s->recv_info},
1953                 {TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
1954                 {TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
1955                 {TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
1956                 {TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
1957                 {TIPC_NLA_STATS_TX_INFO, s->sent_info},
1958                 {TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
1959                 {TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
1960                 {TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
1961                 {TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
1962                 {TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
1963                         s->msg_length_counts : 1},
1964                 {TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
1965                 {TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
1966                 {TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
1967                 {TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
1968                 {TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
1969                 {TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
1970                 {TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
1971                 {TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
1972                 {TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
1973                 {TIPC_NLA_STATS_RX_STATES, s->recv_states},
1974                 {TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
1975                 {TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
1976                 {TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
1977                 {TIPC_NLA_STATS_TX_STATES, s->sent_states},
1978                 {TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
1979                 {TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
1980                 {TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
1981                 {TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
1982                 {TIPC_NLA_STATS_DUPLICATES, s->duplicates},
1983                 {TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
1984                 {TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
1985                 {TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
1986                         (s->accu_queue_sz / s->queue_sz_counts) : 0}
1987         };
1988
1989         stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
1990         if (!stats)
1991                 return -EMSGSIZE;
1992
1993         for (i = 0; i <  ARRAY_SIZE(map); i++)
1994                 if (nla_put_u32(skb, map[i].key, map[i].val))
1995                         goto msg_full;
1996
1997         nla_nest_end(skb, stats);
1998
1999         return 0;
2000 msg_full:
2001         nla_nest_cancel(skb, stats);
2002
2003         return -EMSGSIZE;
2004 }
2005
2006 /* Caller should hold appropriate locks to protect the link */
2007 static int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2008                               struct tipc_link *link, int nlflags)
2009 {
2010         int err;
2011         void *hdr;
2012         struct nlattr *attrs;
2013         struct nlattr *prop;
2014         struct tipc_net *tn = net_generic(net, tipc_net_id);
2015
2016         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2017                           nlflags, TIPC_NL_LINK_GET);
2018         if (!hdr)
2019                 return -EMSGSIZE;
2020
2021         attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
2022         if (!attrs)
2023                 goto msg_full;
2024
2025         if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2026                 goto attr_msg_full;
2027         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
2028                         tipc_cluster_mask(tn->own_addr)))
2029                 goto attr_msg_full;
2030         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
2031                 goto attr_msg_full;
2032         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->rcv_nxt))
2033                 goto attr_msg_full;
2034         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->snd_nxt))
2035                 goto attr_msg_full;
2036
2037         if (tipc_link_is_up(link))
2038                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2039                         goto attr_msg_full;
2040         if (tipc_link_is_active(link))
2041                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2042                         goto attr_msg_full;
2043
2044         prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
2045         if (!prop)
2046                 goto attr_msg_full;
2047         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2048                 goto prop_msg_full;
2049         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2050                 goto prop_msg_full;
2051         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2052                         link->window))
2053                 goto prop_msg_full;
2054         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2055                 goto prop_msg_full;
2056         nla_nest_end(msg->skb, prop);
2057
2058         err = __tipc_nl_add_stats(msg->skb, &link->stats);
2059         if (err)
2060                 goto attr_msg_full;
2061
2062         nla_nest_end(msg->skb, attrs);
2063         genlmsg_end(msg->skb, hdr);
2064
2065         return 0;
2066
2067 prop_msg_full:
2068         nla_nest_cancel(msg->skb, prop);
2069 attr_msg_full:
2070         nla_nest_cancel(msg->skb, attrs);
2071 msg_full:
2072         genlmsg_cancel(msg->skb, hdr);
2073
2074         return -EMSGSIZE;
2075 }
2076
2077 /* Caller should hold node lock  */
2078 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
2079                                     struct tipc_node *node, u32 *prev_link)
2080 {
2081         u32 i;
2082         int err;
2083
2084         for (i = *prev_link; i < MAX_BEARERS; i++) {
2085                 *prev_link = i;
2086
2087                 if (!node->links[i].link)
2088                         continue;
2089
2090                 err = __tipc_nl_add_link(net, msg,
2091                                          node->links[i].link, NLM_F_MULTI);
2092                 if (err)
2093                         return err;
2094         }
2095         *prev_link = 0;
2096
2097         return 0;
2098 }
2099
2100 int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
2101 {
2102         struct net *net = sock_net(skb->sk);
2103         struct tipc_net *tn = net_generic(net, tipc_net_id);
2104         struct tipc_node *node;
2105         struct tipc_nl_msg msg;
2106         u32 prev_node = cb->args[0];
2107         u32 prev_link = cb->args[1];
2108         int done = cb->args[2];
2109         int err;
2110
2111         if (done)
2112                 return 0;
2113
2114         msg.skb = skb;
2115         msg.portid = NETLINK_CB(cb->skb).portid;
2116         msg.seq = cb->nlh->nlmsg_seq;
2117
2118         rcu_read_lock();
2119         if (prev_node) {
2120                 node = tipc_node_find(net, prev_node);
2121                 if (!node) {
2122                         /* We never set seq or call nl_dump_check_consistent()
2123                          * this means that setting prev_seq here will cause the
2124                          * consistence check to fail in the netlink callback
2125                          * handler. Resulting in the last NLMSG_DONE message
2126                          * having the NLM_F_DUMP_INTR flag set.
2127                          */
2128                         cb->prev_seq = 1;
2129                         goto out;
2130                 }
2131                 tipc_node_put(node);
2132
2133                 list_for_each_entry_continue_rcu(node, &tn->node_list,
2134                                                  list) {
2135                         tipc_node_lock(node);
2136                         err = __tipc_nl_add_node_links(net, &msg, node,
2137                                                        &prev_link);
2138                         tipc_node_unlock(node);
2139                         if (err)
2140                                 goto out;
2141
2142                         prev_node = node->addr;
2143                 }
2144         } else {
2145                 err = tipc_nl_add_bc_link(net, &msg);
2146                 if (err)
2147                         goto out;
2148
2149                 list_for_each_entry_rcu(node, &tn->node_list, list) {
2150                         tipc_node_lock(node);
2151                         err = __tipc_nl_add_node_links(net, &msg, node,
2152                                                        &prev_link);
2153                         tipc_node_unlock(node);
2154                         if (err)
2155                                 goto out;
2156
2157                         prev_node = node->addr;
2158                 }
2159         }
2160         done = 1;
2161 out:
2162         rcu_read_unlock();
2163
2164         cb->args[0] = prev_node;
2165         cb->args[1] = prev_link;
2166         cb->args[2] = done;
2167
2168         return skb->len;
2169 }
2170
2171 int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
2172 {
2173         struct net *net = genl_info_net(info);
2174         struct tipc_nl_msg msg;
2175         char *name;
2176         int err;
2177
2178         msg.portid = info->snd_portid;
2179         msg.seq = info->snd_seq;
2180
2181         if (!info->attrs[TIPC_NLA_LINK_NAME])
2182                 return -EINVAL;
2183         name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
2184
2185         msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
2186         if (!msg.skb)
2187                 return -ENOMEM;
2188
2189         if (strcmp(name, tipc_bclink_name) == 0) {
2190                 err = tipc_nl_add_bc_link(net, &msg);
2191                 if (err) {
2192                         nlmsg_free(msg.skb);
2193                         return err;
2194                 }
2195         } else {
2196                 int bearer_id;
2197                 struct tipc_node *node;
2198                 struct tipc_link *link;
2199
2200                 node = tipc_link_find_owner(net, name, &bearer_id);
2201                 if (!node)
2202                         return -EINVAL;
2203
2204                 tipc_node_lock(node);
2205                 link = node->links[bearer_id].link;
2206                 if (!link) {
2207                         tipc_node_unlock(node);
2208                         nlmsg_free(msg.skb);
2209                         return -EINVAL;
2210                 }
2211
2212                 err = __tipc_nl_add_link(net, &msg, link, 0);
2213                 tipc_node_unlock(node);
2214                 if (err) {
2215                         nlmsg_free(msg.skb);
2216                         return err;
2217                 }
2218         }
2219
2220         return genlmsg_reply(msg.skb, info);
2221 }
2222
2223 int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
2224 {
2225         int err;
2226         char *link_name;
2227         unsigned int bearer_id;
2228         struct tipc_link *link;
2229         struct tipc_node *node;
2230         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
2231         struct net *net = sock_net(skb->sk);
2232
2233         if (!info->attrs[TIPC_NLA_LINK])
2234                 return -EINVAL;
2235
2236         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
2237                                info->attrs[TIPC_NLA_LINK],
2238                                tipc_nl_link_policy);
2239         if (err)
2240                 return err;
2241
2242         if (!attrs[TIPC_NLA_LINK_NAME])
2243                 return -EINVAL;
2244
2245         link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
2246
2247         if (strcmp(link_name, tipc_bclink_name) == 0) {
2248                 err = tipc_bclink_reset_stats(net);
2249                 if (err)
2250                         return err;
2251                 return 0;
2252         }
2253
2254         node = tipc_link_find_owner(net, link_name, &bearer_id);
2255         if (!node)
2256                 return -EINVAL;
2257
2258         tipc_node_lock(node);
2259
2260         link = node->links[bearer_id].link;
2261         if (!link) {
2262                 tipc_node_unlock(node);
2263                 return -EINVAL;
2264         }
2265
2266         link_reset_statistics(link);
2267
2268         tipc_node_unlock(node);
2269
2270         return 0;
2271 }