net/tipc/link.c

   1 /*
   2  * net/tipc/link.c: TIPC link code
   3  *
   4  * Copyright (c) 1996-2007, 2012-2014, 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 "link.h"
  39 #include "bcast.h"
  40 #include "socket.h"
  41 #include "name_distr.h"
  42 #include "discover.h"
  43 #include "netlink.h"
  44
  45 #include <linux/pkt_sched.h>
  46
  47 /*
  48  * Error message prefixes
  49  */
  50 static const char *link_co_err = "Link changeover error, ";
  51 static const char *link_rst_msg = "Resetting link ";
  52 static const char *link_unk_evt = "Unknown link event ";
  53
  54 static const struct nla_policy tipc_nl_link_policy[TIPC_NLA_LINK_MAX + 1] = {
  55         [TIPC_NLA_LINK_UNSPEC]          = { .type = NLA_UNSPEC },
  56         [TIPC_NLA_LINK_NAME] = {
  57                 .type = NLA_STRING,
  58                 .len = TIPC_MAX_LINK_NAME
  59         },
  60         [TIPC_NLA_LINK_MTU]             = { .type = NLA_U32 },
  61         [TIPC_NLA_LINK_BROADCAST]       = { .type = NLA_FLAG },
  62         [TIPC_NLA_LINK_UP]              = { .type = NLA_FLAG },
  63         [TIPC_NLA_LINK_ACTIVE]          = { .type = NLA_FLAG },
  64         [TIPC_NLA_LINK_PROP]            = { .type = NLA_NESTED },
  65         [TIPC_NLA_LINK_STATS]           = { .type = NLA_NESTED },
  66         [TIPC_NLA_LINK_RX]              = { .type = NLA_U32 },
  67         [TIPC_NLA_LINK_TX]              = { .type = NLA_U32 }
  68 };
  69
  70 /* Properties valid for media, bearar and link */
  71 static const struct nla_policy tipc_nl_prop_policy[TIPC_NLA_PROP_MAX + 1] = {
  72         [TIPC_NLA_PROP_UNSPEC]          = { .type = NLA_UNSPEC },
  73         [TIPC_NLA_PROP_PRIO]            = { .type = NLA_U32 },
  74         [TIPC_NLA_PROP_TOL]             = { .type = NLA_U32 },
  75         [TIPC_NLA_PROP_WIN]             = { .type = NLA_U32 }
  76 };
  77
  78 /*
  79  * Out-of-range value for link session numbers
  80  */
  81 #define INVALID_SESSION 0x10000
  82
  83 /*
  84  * Link state events:
  85  */
  86 #define  STARTING_EVT    856384768      /* link processing trigger */
  87 #define  TRAFFIC_MSG_EVT 560815u        /* rx'd ??? */
  88 #define  TIMEOUT_EVT     560817u        /* link timer expired */
  89
  90 /*
  91  * The following two 'message types' is really just implementation
  92  * data conveniently stored in the message header.
  93  * They must not be considered part of the protocol
  94  */
  95 #define OPEN_MSG   0
  96 #define CLOSED_MSG 1
  97
  98 /*
  99  * State value stored in 'exp_msg_count'
 100  */
 101 #define START_CHANGEOVER 100000u
 102
 103 static void link_handle_out_of_seq_msg(struct tipc_link *link,
 104                                        struct sk_buff *skb);
 105 static void tipc_link_proto_rcv(struct tipc_link *link,
 106                                 struct sk_buff *skb);
 107 static int  tipc_link_tunnel_rcv(struct tipc_node *node,
 108                                  struct sk_buff **skb);
 109 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tol);
 110 static void link_state_event(struct tipc_link *l_ptr, u32 event);
 111 static void link_reset_statistics(struct tipc_link *l_ptr);
 112 static void link_print(struct tipc_link *l_ptr, const char *str);
 113 static void tipc_link_sync_xmit(struct tipc_link *l);
 114 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf);
 115 static void tipc_link_input(struct tipc_link *l, struct sk_buff *skb);
 116 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb);
 117
 118 /*
 119  *  Simple link routines
 120  */
 121 static unsigned int align(unsigned int i)
 122 {
 123         return (i + 3) & ~3u;
 124 }
 125
 126 static void tipc_link_release(struct kref *kref)
 127 {
 128         kfree(container_of(kref, struct tipc_link, ref));
 129 }
 130
 131 static void tipc_link_get(struct tipc_link *l_ptr)
 132 {
 133         kref_get(&l_ptr->ref);
 134 }
 135
 136 static void tipc_link_put(struct tipc_link *l_ptr)
 137 {
 138         kref_put(&l_ptr->ref, tipc_link_release);
 139 }
 140
 141 static void link_init_max_pkt(struct tipc_link *l_ptr)
 142 {
 143         struct tipc_node *node = l_ptr->owner;
 144         struct tipc_net *tn = net_generic(node->net, tipc_net_id);
 145         struct tipc_bearer *b_ptr;
 146         u32 max_pkt;
 147
 148         rcu_read_lock();
 149         b_ptr = rcu_dereference_rtnl(tn->bearer_list[l_ptr->bearer_id]);
 150         if (!b_ptr) {
 151                 rcu_read_unlock();
 152                 return;
 153         }
 154         max_pkt = (b_ptr->mtu & ~3);
 155         rcu_read_unlock();
 156
 157         if (max_pkt > MAX_MSG_SIZE)
 158                 max_pkt = MAX_MSG_SIZE;
 159
 160         l_ptr->max_pkt_target = max_pkt;
 161         if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
 162                 l_ptr->max_pkt = l_ptr->max_pkt_target;
 163         else
 164                 l_ptr->max_pkt = MAX_PKT_DEFAULT;
 165
 166         l_ptr->max_pkt_probes = 0;
 167 }
 168
 169 /*
 170  *  Simple non-static link routines (i.e. referenced outside this file)
 171  */
 172 int tipc_link_is_up(struct tipc_link *l_ptr)
 173 {
 174         if (!l_ptr)
 175                 return 0;
 176         return link_working_working(l_ptr) || link_working_unknown(l_ptr);
 177 }
 178
 179 int tipc_link_is_active(struct tipc_link *l_ptr)
 180 {
 181         return  (l_ptr->owner->active_links[0] == l_ptr) ||
 182                 (l_ptr->owner->active_links[1] == l_ptr);
 183 }
 184
 185 /**
 186  * link_timeout - handle expiration of link timer
 187  * @l_ptr: pointer to link
 188  */
 189 static void link_timeout(unsigned long data)
 190 {
 191         struct tipc_link *l_ptr = (struct tipc_link *)data;
 192         struct sk_buff *skb;
 193
 194         tipc_node_lock(l_ptr->owner);
 195
 196         /* update counters used in statistical profiling of send traffic */
 197         l_ptr->stats.accu_queue_sz += skb_queue_len(&l_ptr->outqueue);
 198         l_ptr->stats.queue_sz_counts++;
 199
 200         skb = skb_peek(&l_ptr->outqueue);
 201         if (skb) {
 202                 struct tipc_msg *msg = buf_msg(skb);
 203                 u32 length = msg_size(msg);
 204
 205                 if ((msg_user(msg) == MSG_FRAGMENTER) &&
 206                     (msg_type(msg) == FIRST_FRAGMENT)) {
 207                         length = msg_size(msg_get_wrapped(msg));
 208                 }
 209                 if (length) {
 210                         l_ptr->stats.msg_lengths_total += length;
 211                         l_ptr->stats.msg_length_counts++;
 212                         if (length <= 64)
 213                                 l_ptr->stats.msg_length_profile[0]++;
 214                         else if (length <= 256)
 215                                 l_ptr->stats.msg_length_profile[1]++;
 216                         else if (length <= 1024)
 217                                 l_ptr->stats.msg_length_profile[2]++;
 218                         else if (length <= 4096)
 219                                 l_ptr->stats.msg_length_profile[3]++;
 220                         else if (length <= 16384)
 221                                 l_ptr->stats.msg_length_profile[4]++;
 222                         else if (length <= 32768)
 223                                 l_ptr->stats.msg_length_profile[5]++;
 224                         else
 225                                 l_ptr->stats.msg_length_profile[6]++;
 226                 }
 227         }
 228
 229         /* do all other link processing performed on a periodic basis */
 230         link_state_event(l_ptr, TIMEOUT_EVT);
 231
 232         if (l_ptr->next_out)
 233                 tipc_link_push_packets(l_ptr);
 234
 235         tipc_node_unlock(l_ptr->owner);
 236         tipc_link_put(l_ptr);
 237 }
 238
 239 static void link_set_timer(struct tipc_link *link, unsigned long time)
 240 {
 241         if (!mod_timer(&link->timer, jiffies + time))
 242                 tipc_link_get(link);
 243 }
 244
 245 /**
 246  * tipc_link_create - create a new link
 247  * @n_ptr: pointer to associated node
 248  * @b_ptr: pointer to associated bearer
 249  * @media_addr: media address to use when sending messages over link
 250  *
 251  * Returns pointer to link.
 252  */
 253 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
 254                                    struct tipc_bearer *b_ptr,
 255                                    const struct tipc_media_addr *media_addr)
 256 {
 257         struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
 258         struct tipc_link *l_ptr;
 259         struct tipc_msg *msg;
 260         char *if_name;
 261         char addr_string[16];
 262         u32 peer = n_ptr->addr;
 263
 264         if (n_ptr->link_cnt >= MAX_BEARERS) {
 265                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 266                 pr_err("Attempt to establish %uth link to %s. Max %u allowed.\n",
 267                         n_ptr->link_cnt, addr_string, MAX_BEARERS);
 268                 return NULL;
 269         }
 270
 271         if (n_ptr->links[b_ptr->identity]) {
 272                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 273                 pr_err("Attempt to establish second link on <%s> to %s\n",
 274                        b_ptr->name, addr_string);
 275                 return NULL;
 276         }
 277
 278         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 279         if (!l_ptr) {
 280                 pr_warn("Link creation failed, no memory\n");
 281                 return NULL;
 282         }
 283         kref_init(&l_ptr->ref);
 284         l_ptr->addr = peer;
 285         if_name = strchr(b_ptr->name, ':') + 1;
 286         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 287                 tipc_zone(tn->own_addr), tipc_cluster(tn->own_addr),
 288                 tipc_node(tn->own_addr),
 289                 if_name,
 290                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 291                 /* note: peer i/f name is updated by reset/activate message */
 292         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 293         l_ptr->owner = n_ptr;
 294         l_ptr->checkpoint = 1;
 295         l_ptr->peer_session = INVALID_SESSION;
 296         l_ptr->bearer_id = b_ptr->identity;
 297         link_set_supervision_props(l_ptr, b_ptr->tolerance);
 298         l_ptr->state = RESET_UNKNOWN;
 299
 300         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 301         msg = l_ptr->pmsg;
 302         tipc_msg_init(tn->own_addr, msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE,
 303                       l_ptr->addr);
 304         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 305         msg_set_session(msg, (tn->random & 0xffff));
 306         msg_set_bearer_id(msg, b_ptr->identity);
 307         strcpy((char *)msg_data(msg), if_name);
 308
 309         l_ptr->priority = b_ptr->priority;
 310         tipc_link_set_queue_limits(l_ptr, b_ptr->window);
 311
 312         l_ptr->net_plane = b_ptr->net_plane;
 313         link_init_max_pkt(l_ptr);
 314
 315         l_ptr->next_out_no = 1;
 316         __skb_queue_head_init(&l_ptr->outqueue);
 317         __skb_queue_head_init(&l_ptr->deferred_queue);
 318         skb_queue_head_init(&l_ptr->wakeupq);
 319         skb_queue_head_init(&l_ptr->inputq);
 320         skb_queue_head_init(&l_ptr->namedq);
 321         link_reset_statistics(l_ptr);
 322         tipc_node_attach_link(n_ptr, l_ptr);
 323         setup_timer(&l_ptr->timer, link_timeout, (unsigned long)l_ptr);
 324         link_state_event(l_ptr, STARTING_EVT);
 325
 326         return l_ptr;
 327 }
 328
 329 /**
 330  * link_delete - Conditional deletion of link.
 331  *               If timer still running, real delete is done when it expires
 332  * @link: link to be deleted
 333  */
 334 void tipc_link_delete(struct tipc_link *link)
 335 {
 336         tipc_link_reset_fragments(link);
 337         tipc_node_detach_link(link->owner, link);
 338         tipc_link_put(link);
 339 }
 340
 341 void tipc_link_delete_list(struct net *net, unsigned int bearer_id,
 342                            bool shutting_down)
 343 {
 344         struct tipc_net *tn = net_generic(net, tipc_net_id);
 345         struct tipc_link *link;
 346         struct tipc_node *node;
 347         bool del_link;
 348
 349         rcu_read_lock();
 350         list_for_each_entry_rcu(node, &tn->node_list, list) {
 351                 tipc_node_lock(node);
 352                 link = node->links[bearer_id];
 353                 if (!link) {
 354                         tipc_node_unlock(node);
 355                         continue;
 356                 }
 357                 del_link = !tipc_link_is_up(link) && !link->exp_msg_count;
 358                 tipc_link_reset(link);
 359                 if (del_timer(&link->timer))
 360                         tipc_link_put(link);
 361                 link->flags |= LINK_STOPPED;
 362                 /* Delete link now, or when failover is finished: */
 363                 if (shutting_down || !tipc_node_is_up(node) || del_link)
 364                         tipc_link_delete(link);
 365                 tipc_node_unlock(node);
 366         }
 367         rcu_read_unlock();
 368 }
 369
 370 /**
 371  * link_schedule_user - schedule user for wakeup after congestion
 372  * @link: congested link
 373  * @oport: sending port
 374  * @chain_sz: size of buffer chain that was attempted sent
 375  * @imp: importance of message attempted sent
 376  * Create pseudo msg to send back to user when congestion abates
 377  */
 378 static bool link_schedule_user(struct tipc_link *link, u32 oport,
 379                                uint chain_sz, uint imp)
 380 {
 381         struct sk_buff *buf;
 382
 383         buf = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
 384                               link_own_addr(link), link_own_addr(link),
 385                               oport, 0, 0);
 386         if (!buf)
 387                 return false;
 388         TIPC_SKB_CB(buf)->chain_sz = chain_sz;
 389         TIPC_SKB_CB(buf)->chain_imp = imp;
 390         skb_queue_tail(&link->wakeupq, buf);
 391         link->stats.link_congs++;
 392         return true;
 393 }
 394
 395 /**
 396  * link_prepare_wakeup - prepare users for wakeup after congestion
 397  * @link: congested link
 398  * Move a number of waiting users, as permitted by available space in
 399  * the send queue, from link wait queue to node wait queue for wakeup
 400  */
 401 void link_prepare_wakeup(struct tipc_link *link)
 402 {
 403         uint pend_qsz = skb_queue_len(&link->outqueue);
 404         struct sk_buff *skb, *tmp;
 405
 406         skb_queue_walk_safe(&link->wakeupq, skb, tmp) {
 407                 if (pend_qsz >= link->queue_limit[TIPC_SKB_CB(skb)->chain_imp])
 408                         break;
 409                 pend_qsz += TIPC_SKB_CB(skb)->chain_sz;
 410                 skb_unlink(skb, &link->wakeupq);
 411                 skb_queue_tail(&link->inputq, skb);
 412                 link->owner->inputq = &link->inputq;
 413                 link->owner->action_flags |= TIPC_MSG_EVT;
 414         }
 415 }
 416
 417 /**
 418  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 419  * @l_ptr: pointer to link
 420  */
 421 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 422 {
 423         kfree_skb(l_ptr->reasm_buf);
 424         l_ptr->reasm_buf = NULL;
 425 }
 426
 427 /**
 428  * tipc_link_purge_queues - purge all pkt queues associated with link
 429  * @l_ptr: pointer to link
 430  */
 431 void tipc_link_purge_queues(struct tipc_link *l_ptr)
 432 {
 433         __skb_queue_purge(&l_ptr->deferred_queue);
 434         __skb_queue_purge(&l_ptr->outqueue);
 435         tipc_link_reset_fragments(l_ptr);
 436 }
 437
 438 void tipc_link_reset(struct tipc_link *l_ptr)
 439 {
 440         u32 prev_state = l_ptr->state;
 441         u32 checkpoint = l_ptr->next_in_no;
 442         int was_active_link = tipc_link_is_active(l_ptr);
 443         struct tipc_node *owner = l_ptr->owner;
 444
 445         msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
 446
 447         /* Link is down, accept any session */
 448         l_ptr->peer_session = INVALID_SESSION;
 449
 450         /* Prepare for max packet size negotiation */
 451         link_init_max_pkt(l_ptr);
 452
 453         l_ptr->state = RESET_UNKNOWN;
 454
 455         if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
 456                 return;
 457
 458         tipc_node_link_down(l_ptr->owner, l_ptr);
 459         tipc_bearer_remove_dest(owner->net, l_ptr->bearer_id, l_ptr->addr);
 460
 461         if (was_active_link && tipc_node_active_links(l_ptr->owner)) {
 462                 l_ptr->reset_checkpoint = checkpoint;
 463                 l_ptr->exp_msg_count = START_CHANGEOVER;
 464         }
 465
 466         /* Clean up all queues, except inputq: */
 467         __skb_queue_purge(&l_ptr->outqueue);
 468         __skb_queue_purge(&l_ptr->deferred_queue);
 469         if (!owner->inputq)
 470                 owner->inputq = &l_ptr->inputq;
 471         skb_queue_splice_init(&l_ptr->wakeupq, owner->inputq);
 472         if (!skb_queue_empty(owner->inputq))
 473                 owner->action_flags |= TIPC_MSG_EVT;
 474         l_ptr->next_out = NULL;
 475         l_ptr->unacked_window = 0;
 476         l_ptr->checkpoint = 1;
 477         l_ptr->next_out_no = 1;
 478         l_ptr->fsm_msg_cnt = 0;
 479         l_ptr->stale_count = 0;
 480         link_reset_statistics(l_ptr);
 481 }
 482
 483 void tipc_link_reset_list(struct net *net, unsigned int bearer_id)
 484 {
 485         struct tipc_net *tn = net_generic(net, tipc_net_id);
 486         struct tipc_link *l_ptr;
 487         struct tipc_node *n_ptr;
 488
 489         rcu_read_lock();
 490         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
 491                 tipc_node_lock(n_ptr);
 492                 l_ptr = n_ptr->links[bearer_id];
 493                 if (l_ptr)
 494                         tipc_link_reset(l_ptr);
 495                 tipc_node_unlock(n_ptr);
 496         }
 497         rcu_read_unlock();
 498 }
 499
 500 static void link_activate(struct tipc_link *link)
 501 {
 502         struct tipc_node *node = link->owner;
 503
 504         link->next_in_no = 1;
 505         link->stats.recv_info = 1;
 506         tipc_node_link_up(node, link);
 507         tipc_bearer_add_dest(node->net, link->bearer_id, link->addr);
 508 }
 509
 510 /**
 511  * link_state_event - link finite state machine
 512  * @l_ptr: pointer to link
 513  * @event: state machine event to process
 514  */
 515 static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
 516 {
 517         struct tipc_link *other;
 518         unsigned long cont_intv = l_ptr->cont_intv;
 519
 520         if (l_ptr->flags & LINK_STOPPED)
 521                 return;
 522
 523         if (!(l_ptr->flags & LINK_STARTED) && (event != STARTING_EVT))
 524                 return;         /* Not yet. */
 525
 526         /* Check whether changeover is going on */
 527         if (l_ptr->exp_msg_count) {
 528                 if (event == TIMEOUT_EVT)
 529                         link_set_timer(l_ptr, cont_intv);
 530                 return;
 531         }
 532
 533         switch (l_ptr->state) {
 534         case WORKING_WORKING:
 535                 switch (event) {
 536                 case TRAFFIC_MSG_EVT:
 537                 case ACTIVATE_MSG:
 538                         break;
 539                 case TIMEOUT_EVT:
 540                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 541                                 l_ptr->checkpoint = l_ptr->next_in_no;
 542                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 543                                         tipc_link_proto_xmit(l_ptr, STATE_MSG,
 544                                                              0, 0, 0, 0, 0);
 545                                         l_ptr->fsm_msg_cnt++;
 546                                 } else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
 547                                         tipc_link_proto_xmit(l_ptr, STATE_MSG,
 548                                                              1, 0, 0, 0, 0);
 549                                         l_ptr->fsm_msg_cnt++;
 550                                 }
 551                                 link_set_timer(l_ptr, cont_intv);
 552                                 break;
 553                         }
 554                         l_ptr->state = WORKING_UNKNOWN;
 555                         l_ptr->fsm_msg_cnt = 0;
 556                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 557                         l_ptr->fsm_msg_cnt++;
 558                         link_set_timer(l_ptr, cont_intv / 4);
 559                         break;
 560                 case RESET_MSG:
 561                         pr_debug("%s<%s>, requested by peer\n",
 562                                  link_rst_msg, l_ptr->name);
 563                         tipc_link_reset(l_ptr);
 564                         l_ptr->state = RESET_RESET;
 565                         l_ptr->fsm_msg_cnt = 0;
 566                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 567                                              0, 0, 0, 0, 0);
 568                         l_ptr->fsm_msg_cnt++;
 569                         link_set_timer(l_ptr, cont_intv);
 570                         break;
 571                 default:
 572                         pr_debug("%s%u in WW state\n", link_unk_evt, event);
 573                 }
 574                 break;
 575         case WORKING_UNKNOWN:
 576                 switch (event) {
 577                 case TRAFFIC_MSG_EVT:
 578                 case ACTIVATE_MSG:
 579                         l_ptr->state = WORKING_WORKING;
 580                         l_ptr->fsm_msg_cnt = 0;
 581                         link_set_timer(l_ptr, cont_intv);
 582                         break;
 583                 case RESET_MSG:
 584                         pr_debug("%s<%s>, requested by peer while probing\n",
 585                                  link_rst_msg, l_ptr->name);
 586                         tipc_link_reset(l_ptr);
 587                         l_ptr->state = RESET_RESET;
 588                         l_ptr->fsm_msg_cnt = 0;
 589                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 590                                              0, 0, 0, 0, 0);
 591                         l_ptr->fsm_msg_cnt++;
 592                         link_set_timer(l_ptr, cont_intv);
 593                         break;
 594                 case TIMEOUT_EVT:
 595                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 596                                 l_ptr->state = WORKING_WORKING;
 597                                 l_ptr->fsm_msg_cnt = 0;
 598                                 l_ptr->checkpoint = l_ptr->next_in_no;
 599                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 600                                         tipc_link_proto_xmit(l_ptr, STATE_MSG,
 601                                                              0, 0, 0, 0, 0);
 602                                         l_ptr->fsm_msg_cnt++;
 603                                 }
 604                                 link_set_timer(l_ptr, cont_intv);
 605                         } else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
 606                                 tipc_link_proto_xmit(l_ptr, STATE_MSG,
 607                                                      1, 0, 0, 0, 0);
 608                                 l_ptr->fsm_msg_cnt++;
 609                                 link_set_timer(l_ptr, cont_intv / 4);
 610                         } else {        /* Link has failed */
 611                                 pr_debug("%s<%s>, peer not responding\n",
 612                                          link_rst_msg, l_ptr->name);
 613                                 tipc_link_reset(l_ptr);
 614                                 l_ptr->state = RESET_UNKNOWN;
 615                                 l_ptr->fsm_msg_cnt = 0;
 616                                 tipc_link_proto_xmit(l_ptr, RESET_MSG,
 617                                                      0, 0, 0, 0, 0);
 618                                 l_ptr->fsm_msg_cnt++;
 619                                 link_set_timer(l_ptr, cont_intv);
 620                         }
 621                         break;
 622                 default:
 623                         pr_err("%s%u in WU state\n", link_unk_evt, event);
 624                 }
 625                 break;
 626         case RESET_UNKNOWN:
 627                 switch (event) {
 628                 case TRAFFIC_MSG_EVT:
 629                         break;
 630                 case ACTIVATE_MSG:
 631                         other = l_ptr->owner->active_links[0];
 632                         if (other && link_working_unknown(other))
 633                                 break;
 634                         l_ptr->state = WORKING_WORKING;
 635                         l_ptr->fsm_msg_cnt = 0;
 636                         link_activate(l_ptr);
 637                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 638                         l_ptr->fsm_msg_cnt++;
 639                         if (l_ptr->owner->working_links == 1)
 640                                 tipc_link_sync_xmit(l_ptr);
 641                         link_set_timer(l_ptr, cont_intv);
 642                         break;
 643                 case RESET_MSG:
 644                         l_ptr->state = RESET_RESET;
 645                         l_ptr->fsm_msg_cnt = 0;
 646                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 647                                              1, 0, 0, 0, 0);
 648                         l_ptr->fsm_msg_cnt++;
 649                         link_set_timer(l_ptr, cont_intv);
 650                         break;
 651                 case STARTING_EVT:
 652                         l_ptr->flags |= LINK_STARTED;
 653                         l_ptr->fsm_msg_cnt++;
 654                         link_set_timer(l_ptr, cont_intv);
 655                         break;
 656                 case TIMEOUT_EVT:
 657                         tipc_link_proto_xmit(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
 658                         l_ptr->fsm_msg_cnt++;
 659                         link_set_timer(l_ptr, cont_intv);
 660                         break;
 661                 default:
 662                         pr_err("%s%u in RU state\n", link_unk_evt, event);
 663                 }
 664                 break;
 665         case RESET_RESET:
 666                 switch (event) {
 667                 case TRAFFIC_MSG_EVT:
 668                 case ACTIVATE_MSG:
 669                         other = l_ptr->owner->active_links[0];
 670                         if (other && link_working_unknown(other))
 671                                 break;
 672                         l_ptr->state = WORKING_WORKING;
 673                         l_ptr->fsm_msg_cnt = 0;
 674                         link_activate(l_ptr);
 675                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 676                         l_ptr->fsm_msg_cnt++;
 677                         if (l_ptr->owner->working_links == 1)
 678                                 tipc_link_sync_xmit(l_ptr);
 679                         link_set_timer(l_ptr, cont_intv);
 680                         break;
 681                 case RESET_MSG:
 682                         break;
 683                 case TIMEOUT_EVT:
 684                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 685                                              0, 0, 0, 0, 0);
 686                         l_ptr->fsm_msg_cnt++;
 687                         link_set_timer(l_ptr, cont_intv);
 688                         break;
 689                 default:
 690                         pr_err("%s%u in RR state\n", link_unk_evt, event);
 691                 }
 692                 break;
 693         default:
 694                 pr_err("Unknown link state %u/%u\n", l_ptr->state, event);
 695         }
 696 }
 697
 698 /* tipc_link_cong: determine return value and how to treat the
 699  * sent buffer during link congestion.
 700  * - For plain, errorless user data messages we keep the buffer and
 701  *   return -ELINKONG.
 702  * - For all other messages we discard the buffer and return -EHOSTUNREACH
 703  * - For TIPC internal messages we also reset the link
 704  */
 705 static int tipc_link_cong(struct tipc_link *link, struct sk_buff_head *list)
 706 {
 707         struct sk_buff *skb = skb_peek(list);
 708         struct tipc_msg *msg = buf_msg(skb);
 709         uint imp = tipc_msg_tot_importance(msg);
 710         u32 oport = msg_tot_origport(msg);
 711
 712         if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
 713                 pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
 714                 tipc_link_reset(link);
 715                 goto drop;
 716         }
 717         if (unlikely(msg_errcode(msg)))
 718                 goto drop;
 719         if (unlikely(msg_reroute_cnt(msg)))
 720                 goto drop;
 721         if (TIPC_SKB_CB(skb)->wakeup_pending)
 722                 return -ELINKCONG;
 723         if (link_schedule_user(link, oport, skb_queue_len(list), imp))
 724                 return -ELINKCONG;
 725 drop:
 726         __skb_queue_purge(list);
 727         return -EHOSTUNREACH;
 728 }
 729
 730 /**
 731  * __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
 732  * @link: link to use
 733  * @list: chain of buffers containing message
 734  *
 735  * Consumes the buffer chain, except when returning -ELINKCONG
 736  * Returns 0 if success, otherwise errno: -ELINKCONG, -EMSGSIZE (plain socket
 737  * user data messages) or -EHOSTUNREACH (all other messages/senders)
 738  * Only the socket functions tipc_send_stream() and tipc_send_packet() need
 739  * to act on the return value, since they may need to do more send attempts.
 740  */
 741 int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 742                      struct sk_buff_head *list)
 743 {
 744         struct tipc_msg *msg = buf_msg(skb_peek(list));
 745         uint psz = msg_size(msg);
 746         uint sndlim = link->queue_limit[0];
 747         uint imp = tipc_msg_tot_importance(msg);
 748         uint mtu = link->max_pkt;
 749         uint ack = mod(link->next_in_no - 1);
 750         uint seqno = link->next_out_no;
 751         uint bc_last_in = link->owner->bclink.last_in;
 752         struct tipc_media_addr *addr = &link->media_addr;
 753         struct sk_buff_head *outqueue = &link->outqueue;
 754         struct sk_buff *skb, *tmp;
 755
 756         /* Match queue limits against msg importance: */
 757         if (unlikely(skb_queue_len(outqueue) >= link->queue_limit[imp]))
 758                 return tipc_link_cong(link, list);
 759
 760         /* Has valid packet limit been used ? */
 761         if (unlikely(psz > mtu)) {
 762                 __skb_queue_purge(list);
 763                 return -EMSGSIZE;
 764         }
 765
 766         /* Prepare each packet for sending, and add to outqueue: */
 767         skb_queue_walk_safe(list, skb, tmp) {
 768                 __skb_unlink(skb, list);
 769                 msg = buf_msg(skb);
 770                 msg_set_word(msg, 2, ((ack << 16) | mod(seqno)));
 771                 msg_set_bcast_ack(msg, bc_last_in);
 772
 773                 if (skb_queue_len(outqueue) < sndlim) {
 774                         __skb_queue_tail(outqueue, skb);
 775                         tipc_bearer_send(net, link->bearer_id,
 776                                          skb, addr);
 777                         link->next_out = NULL;
 778                         link->unacked_window = 0;
 779                 } else if (tipc_msg_bundle(outqueue, skb, mtu)) {
 780                         link->stats.sent_bundled++;
 781                         continue;
 782                 } else if (tipc_msg_make_bundle(outqueue, skb, mtu,
 783                                                 link->addr)) {
 784                         link->stats.sent_bundled++;
 785                         link->stats.sent_bundles++;
 786                         if (!link->next_out)
 787                                 link->next_out = skb_peek_tail(outqueue);
 788                 } else {
 789                         __skb_queue_tail(outqueue, skb);
 790                         if (!link->next_out)
 791                                 link->next_out = skb;
 792                 }
 793                 seqno++;
 794         }
 795         link->next_out_no = seqno;
 796         return 0;
 797 }
 798
 799 static void skb2list(struct sk_buff *skb, struct sk_buff_head *list)
 800 {
 801         skb_queue_head_init(list);
 802         __skb_queue_tail(list, skb);
 803 }
 804
 805 static int __tipc_link_xmit_skb(struct tipc_link *link, struct sk_buff *skb)
 806 {
 807         struct sk_buff_head head;
 808
 809         skb2list(skb, &head);
 810         return __tipc_link_xmit(link->owner->net, link, &head);
 811 }
 812
 813 int tipc_link_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
 814                        u32 selector)
 815 {
 816         struct sk_buff_head head;
 817
 818         skb2list(skb, &head);
 819         return tipc_link_xmit(net, &head, dnode, selector);
 820 }
 821
 822 /**
 823  * tipc_link_xmit() is the general link level function for message sending
 824  * @net: the applicable net namespace
 825  * @list: chain of buffers containing message
 826  * @dsz: amount of user data to be sent
 827  * @dnode: address of destination node
 828  * @selector: a number used for deterministic link selection
 829  * Consumes the buffer chain, except when returning -ELINKCONG
 830  * Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
 831  */
 832 int tipc_link_xmit(struct net *net, struct sk_buff_head *list, u32 dnode,
 833                    u32 selector)
 834 {
 835         struct tipc_link *link = NULL;
 836         struct tipc_node *node;
 837         int rc = -EHOSTUNREACH;
 838
 839         node = tipc_node_find(net, dnode);
 840         if (node) {
 841                 tipc_node_lock(node);
 842                 link = node->active_links[selector & 1];
 843                 if (link)
 844                         rc = __tipc_link_xmit(net, link, list);
 845                 tipc_node_unlock(node);
 846         }
 847         if (link)
 848                 return rc;
 849
 850         if (likely(in_own_node(net, dnode)))
 851                 return tipc_sk_rcv(net, list);
 852
 853         __skb_queue_purge(list);
 854         return rc;
 855 }
 856
 857 /*
 858  * tipc_link_sync_xmit - synchronize broadcast link endpoints.
 859  *
 860  * Give a newly added peer node the sequence number where it should
 861  * start receiving and acking broadcast packets.
 862  *
 863  * Called with node locked
 864  */
 865 static void tipc_link_sync_xmit(struct tipc_link *link)
 866 {
 867         struct sk_buff *skb;
 868         struct tipc_msg *msg;
 869
 870         skb = tipc_buf_acquire(INT_H_SIZE);
 871         if (!skb)
 872                 return;
 873
 874         msg = buf_msg(skb);
 875         tipc_msg_init(link_own_addr(link), msg, BCAST_PROTOCOL, STATE_MSG,
 876                       INT_H_SIZE, link->addr);
 877         msg_set_last_bcast(msg, link->owner->bclink.acked);
 878         __tipc_link_xmit_skb(link, skb);
 879 }
 880
 881 /*
 882  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
 883  * Receive the sequence number where we should start receiving and
 884  * acking broadcast packets from a newly added peer node, and open
 885  * up for reception of such packets.
 886  *
 887  * Called with node locked
 888  */
 889 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
 890 {
 891         struct tipc_msg *msg = buf_msg(buf);
 892
 893         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
 894         n->bclink.recv_permitted = true;
 895         kfree_skb(buf);
 896 }
 897
 898 struct sk_buff *tipc_skb_queue_next(const struct sk_buff_head *list,
 899                                     const struct sk_buff *skb)
 900 {
 901         if (skb_queue_is_last(list, skb))
 902                 return NULL;
 903         return skb->next;
 904 }
 905
 906 /*
 907  * tipc_link_push_packets - push unsent packets to bearer
 908  *
 909  * Push out the unsent messages of a link where congestion
 910  * has abated. Node is locked.
 911  *
 912  * Called with node locked
 913  */
 914 void tipc_link_push_packets(struct tipc_link *l_ptr)
 915 {
 916         struct sk_buff_head *outqueue = &l_ptr->outqueue;
 917         struct sk_buff *skb = l_ptr->next_out;
 918         struct tipc_msg *msg;
 919         u32 next, first;
 920
 921         skb_queue_walk_from(outqueue, skb) {
 922                 msg = buf_msg(skb);
 923                 next = msg_seqno(msg);
 924                 first = buf_seqno(skb_peek(outqueue));
 925
 926                 if (mod(next - first) < l_ptr->queue_limit[0]) {
 927                         msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
 928                         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
 929                         if (msg_user(msg) == MSG_BUNDLER)
 930                                 TIPC_SKB_CB(skb)->bundling = false;
 931                         tipc_bearer_send(l_ptr->owner->net,
 932                                          l_ptr->bearer_id, skb,
 933                                          &l_ptr->media_addr);
 934                         l_ptr->next_out = tipc_skb_queue_next(outqueue, skb);
 935                 } else {
 936                         break;
 937                 }
 938         }
 939 }
 940
 941 void tipc_link_reset_all(struct tipc_node *node)
 942 {
 943         char addr_string[16];
 944         u32 i;
 945
 946         tipc_node_lock(node);
 947
 948         pr_warn("Resetting all links to %s\n",
 949                 tipc_addr_string_fill(addr_string, node->addr));
 950
 951         for (i = 0; i < MAX_BEARERS; i++) {
 952                 if (node->links[i]) {
 953                         link_print(node->links[i], "Resetting link\n");
 954                         tipc_link_reset(node->links[i]);
 955                 }
 956         }
 957
 958         tipc_node_unlock(node);
 959 }
 960
 961 static void link_retransmit_failure(struct tipc_link *l_ptr,
 962                                     struct sk_buff *buf)
 963 {
 964         struct tipc_msg *msg = buf_msg(buf);
 965         struct net *net = l_ptr->owner->net;
 966
 967         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
 968
 969         if (l_ptr->addr) {
 970                 /* Handle failure on standard link */
 971                 link_print(l_ptr, "Resetting link\n");
 972                 tipc_link_reset(l_ptr);
 973
 974         } else {
 975                 /* Handle failure on broadcast link */
 976                 struct tipc_node *n_ptr;
 977                 char addr_string[16];
 978
 979                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
 980                 pr_cont("Outstanding acks: %lu\n",
 981                         (unsigned long) TIPC_SKB_CB(buf)->handle);
 982
 983                 n_ptr = tipc_bclink_retransmit_to(net);
 984                 tipc_node_lock(n_ptr);
 985
 986                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 987                 pr_info("Broadcast link info for %s\n", addr_string);
 988                 pr_info("Reception permitted: %d,  Acked: %u\n",
 989                         n_ptr->bclink.recv_permitted,
 990                         n_ptr->bclink.acked);
 991                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
 992                         n_ptr->bclink.last_in,
 993                         n_ptr->bclink.oos_state,
 994                         n_ptr->bclink.last_sent);
 995
 996                 tipc_node_unlock(n_ptr);
 997
 998                 tipc_bclink_set_flags(net, TIPC_BCLINK_RESET);
 999                 l_ptr->stale_count = 0;
1000         }
1001 }
1002
1003 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
1004                           u32 retransmits)
1005 {
1006         struct tipc_msg *msg;
1007
1008         if (!skb)
1009                 return;
1010
1011         msg = buf_msg(skb);
1012
1013         /* Detect repeated retransmit failures */
1014         if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1015                 if (++l_ptr->stale_count > 100) {
1016                         link_retransmit_failure(l_ptr, skb);
1017                         return;
1018                 }
1019         } else {
1020                 l_ptr->last_retransmitted = msg_seqno(msg);
1021                 l_ptr->stale_count = 1;
1022         }
1023
1024         skb_queue_walk_from(&l_ptr->outqueue, skb) {
1025                 if (!retransmits || skb == l_ptr->next_out)
1026                         break;
1027                 msg = buf_msg(skb);
1028                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1029                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1030                 tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, skb,
1031                                  &l_ptr->media_addr);
1032                 retransmits--;
1033                 l_ptr->stats.retransmitted++;
1034         }
1035 }
1036
1037 static void link_retrieve_defq(struct tipc_link *link,
1038                                struct sk_buff_head *list)
1039 {
1040         u32 seq_no;
1041
1042         if (skb_queue_empty(&link->deferred_queue))
1043                 return;
1044
1045         seq_no = buf_seqno(skb_peek(&link->deferred_queue));
1046         if (seq_no == mod(link->next_in_no))
1047                 skb_queue_splice_tail_init(&link->deferred_queue, list);
1048 }
1049
1050 /**
1051  * tipc_rcv - process TIPC packets/messages arriving from off-node
1052  * @net: the applicable net namespace
1053  * @skb: TIPC packet
1054  * @b_ptr: pointer to bearer message arrived on
1055  *
1056  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1057  * structure (i.e. cannot be NULL), but bearer can be inactive.
1058  */
1059 void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b_ptr)
1060 {
1061         struct tipc_net *tn = net_generic(net, tipc_net_id);
1062         struct sk_buff_head head;
1063         struct tipc_node *n_ptr;
1064         struct tipc_link *l_ptr;
1065         struct sk_buff *skb1, *tmp;
1066         struct tipc_msg *msg;
1067         u32 seq_no;
1068         u32 ackd;
1069         u32 released;
1070
1071         skb2list(skb, &head);
1072
1073         while ((skb = __skb_dequeue(&head))) {
1074                 /* Ensure message is well-formed */
1075                 if (unlikely(!tipc_msg_validate(skb)))
1076                         goto discard;
1077
1078                 /* Ensure message data is a single contiguous unit */
1079                 if (unlikely(skb_linearize(skb)))
1080                         goto discard;
1081
1082                 /* Handle arrival of a non-unicast link message */
1083                 msg = buf_msg(skb);
1084
1085                 if (unlikely(msg_non_seq(msg))) {
1086                         if (msg_user(msg) ==  LINK_CONFIG)
1087                                 tipc_disc_rcv(net, skb, b_ptr);
1088                         else
1089                                 tipc_bclink_rcv(net, skb);
1090                         continue;
1091                 }
1092
1093                 /* Discard unicast link messages destined for another node */
1094                 if (unlikely(!msg_short(msg) &&
1095                              (msg_destnode(msg) != tn->own_addr)))
1096                         goto discard;
1097
1098                 /* Locate neighboring node that sent message */
1099                 n_ptr = tipc_node_find(net, msg_prevnode(msg));
1100                 if (unlikely(!n_ptr))
1101                         goto discard;
1102                 tipc_node_lock(n_ptr);
1103
1104                 /* Locate unicast link endpoint that should handle message */
1105                 l_ptr = n_ptr->links[b_ptr->identity];
1106                 if (unlikely(!l_ptr))
1107                         goto unlock;
1108
1109                 /* Verify that communication with node is currently allowed */
1110                 if ((n_ptr->action_flags & TIPC_WAIT_PEER_LINKS_DOWN) &&
1111                     msg_user(msg) == LINK_PROTOCOL &&
1112                     (msg_type(msg) == RESET_MSG ||
1113                     msg_type(msg) == ACTIVATE_MSG) &&
1114                     !msg_redundant_link(msg))
1115                         n_ptr->action_flags &= ~TIPC_WAIT_PEER_LINKS_DOWN;
1116
1117                 if (tipc_node_blocked(n_ptr))
1118                         goto unlock;
1119
1120                 /* Validate message sequence number info */
1121                 seq_no = msg_seqno(msg);
1122                 ackd = msg_ack(msg);
1123
1124                 /* Release acked messages */
1125                 if (n_ptr->bclink.recv_permitted)
1126                         tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1127
1128                 released = 0;
1129                 skb_queue_walk_safe(&l_ptr->outqueue, skb1, tmp) {
1130                         if (skb1 == l_ptr->next_out ||
1131                             more(buf_seqno(skb1), ackd))
1132                                 break;
1133                          __skb_unlink(skb1, &l_ptr->outqueue);
1134                          kfree_skb(skb1);
1135                          released = 1;
1136                 }
1137
1138                 /* Try sending any messages link endpoint has pending */
1139                 if (unlikely(l_ptr->next_out))
1140                         tipc_link_push_packets(l_ptr);
1141
1142                 if (released && !skb_queue_empty(&l_ptr->wakeupq))
1143                         link_prepare_wakeup(l_ptr);
1144
1145                 /* Process the incoming packet */
1146                 if (unlikely(!link_working_working(l_ptr))) {
1147                         if (msg_user(msg) == LINK_PROTOCOL) {
1148                                 tipc_link_proto_rcv(l_ptr, skb);
1149                                 link_retrieve_defq(l_ptr, &head);
1150                                 skb = NULL;
1151                                 goto unlock;
1152                         }
1153
1154                         /* Traffic message. Conditionally activate link */
1155                         link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1156
1157                         if (link_working_working(l_ptr)) {
1158                                 /* Re-insert buffer in front of queue */
1159                                 __skb_queue_head(&head, skb);
1160                                 skb = NULL;
1161                                 goto unlock;
1162                         }
1163                         goto unlock;
1164                 }
1165
1166                 /* Link is now in state WORKING_WORKING */
1167                 if (unlikely(seq_no != mod(l_ptr->next_in_no))) {
1168                         link_handle_out_of_seq_msg(l_ptr, skb);
1169                         link_retrieve_defq(l_ptr, &head);
1170                         skb = NULL;
1171                         goto unlock;
1172                 }
1173                 l_ptr->next_in_no++;
1174                 if (unlikely(!skb_queue_empty(&l_ptr->deferred_queue)))
1175                         link_retrieve_defq(l_ptr, &head);
1176
1177                 if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1178                         l_ptr->stats.sent_acks++;
1179                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1180                 }
1181                 tipc_link_input(l_ptr, skb);
1182                 skb = NULL;
1183 unlock:
1184                 tipc_node_unlock(n_ptr);
1185 discard:
1186                 if (unlikely(skb))
1187                         kfree_skb(skb);
1188         }
1189 }
1190
1191 /* tipc_data_input - deliver data and name distr msgs to upper layer
1192  *
1193  * Consumes buffer if message is of right type
1194  * Node lock must be held
1195  */
1196 static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb)
1197 {
1198         struct tipc_node *node = link->owner;
1199         struct tipc_msg *msg = buf_msg(skb);
1200         u32 dport = msg_destport(msg);
1201
1202         switch (msg_user(msg)) {
1203         case TIPC_LOW_IMPORTANCE:
1204         case TIPC_MEDIUM_IMPORTANCE:
1205         case TIPC_HIGH_IMPORTANCE:
1206         case TIPC_CRITICAL_IMPORTANCE:
1207         case CONN_MANAGER:
1208                 if (tipc_skb_queue_tail(&link->inputq, skb, dport)) {
1209                         node->inputq = &link->inputq;
1210                         node->action_flags |= TIPC_MSG_EVT;
1211                 }
1212                 return true;
1213         case NAME_DISTRIBUTOR:
1214                 node->bclink.recv_permitted = true;
1215                 node->namedq = &link->namedq;
1216                 skb_queue_tail(&link->namedq, skb);
1217                 if (skb_queue_len(&link->namedq) == 1)
1218                         node->action_flags |= TIPC_NAMED_MSG_EVT;
1219                 return true;
1220         case MSG_BUNDLER:
1221         case CHANGEOVER_PROTOCOL:
1222         case MSG_FRAGMENTER:
1223         case BCAST_PROTOCOL:
1224                 return false;
1225         default:
1226                 pr_warn("Dropping received illegal msg type\n");
1227                 kfree_skb(skb);
1228                 return false;
1229         };
1230 }
1231
1232 /* tipc_link_input - process packet that has passed link protocol check
1233  *
1234  * Consumes buffer
1235  * Node lock must be held
1236  */
1237 static void tipc_link_input(struct tipc_link *link, struct sk_buff *skb)
1238 {
1239         struct tipc_node *node = link->owner;
1240         struct tipc_msg *msg = buf_msg(skb);
1241         struct sk_buff *iskb;
1242         int pos = 0;
1243
1244         if (likely(tipc_data_input(link, skb)))
1245                 return;
1246
1247         switch (msg_user(msg)) {
1248         case CHANGEOVER_PROTOCOL:
1249                 if (!tipc_link_tunnel_rcv(node, &skb))
1250                         break;
1251                 if (msg_user(buf_msg(skb)) != MSG_BUNDLER) {
1252                         tipc_data_input(link, skb);
1253                         break;
1254                 }
1255         case MSG_BUNDLER:
1256                 link->stats.recv_bundles++;
1257                 link->stats.recv_bundled += msg_msgcnt(msg);
1258
1259                 while (tipc_msg_extract(skb, &iskb, &pos))
1260                         tipc_data_input(link, iskb);
1261                 break;
1262         case MSG_FRAGMENTER:
1263                 link->stats.recv_fragments++;
1264                 if (tipc_buf_append(&link->reasm_buf, &skb)) {
1265                         link->stats.recv_fragmented++;
1266                         tipc_data_input(link, skb);
1267                 } else if (!link->reasm_buf) {
1268                         tipc_link_reset(link);
1269                 }
1270                 break;
1271         case BCAST_PROTOCOL:
1272                 tipc_link_sync_rcv(node, skb);
1273                 break;
1274         default:
1275                 break;
1276         };
1277 }
1278
1279 /**
1280  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1281  *
1282  * Returns increase in queue length (i.e. 0 or 1)
1283  */
1284 u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
1285 {
1286         struct sk_buff *skb1;
1287         u32 seq_no = buf_seqno(skb);
1288
1289         /* Empty queue ? */
1290         if (skb_queue_empty(list)) {
1291                 __skb_queue_tail(list, skb);
1292                 return 1;
1293         }
1294
1295         /* Last ? */
1296         if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
1297                 __skb_queue_tail(list, skb);
1298                 return 1;
1299         }
1300
1301         /* Locate insertion point in queue, then insert; discard if duplicate */
1302         skb_queue_walk(list, skb1) {
1303                 u32 curr_seqno = buf_seqno(skb1);
1304
1305                 if (seq_no == curr_seqno) {
1306                         kfree_skb(skb);
1307                         return 0;
1308                 }
1309
1310                 if (less(seq_no, curr_seqno))
1311                         break;
1312         }
1313
1314         __skb_queue_before(list, skb1, skb);
1315         return 1;
1316 }
1317
1318 /*
1319  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1320  */
1321 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1322                                        struct sk_buff *buf)
1323 {
1324         u32 seq_no = buf_seqno(buf);
1325
1326         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1327                 tipc_link_proto_rcv(l_ptr, buf);
1328                 return;
1329         }
1330
1331         /* Record OOS packet arrival (force mismatch on next timeout) */
1332         l_ptr->checkpoint--;
1333
1334         /*
1335          * Discard packet if a duplicate; otherwise add it to deferred queue
1336          * and notify peer of gap as per protocol specification
1337          */
1338         if (less(seq_no, mod(l_ptr->next_in_no))) {
1339                 l_ptr->stats.duplicates++;
1340                 kfree_skb(buf);
1341                 return;
1342         }
1343
1344         if (tipc_link_defer_pkt(&l_ptr->deferred_queue, buf)) {
1345                 l_ptr->stats.deferred_recv++;
1346                 if ((skb_queue_len(&l_ptr->deferred_queue) % 16) == 1)
1347                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1348         } else {
1349                 l_ptr->stats.duplicates++;
1350         }
1351 }
1352
1353 /*
1354  * Send protocol message to the other endpoint.
1355  */
1356 void tipc_link_proto_xmit(struct tipc_link *l_ptr, u32 msg_typ, int probe_msg,
1357                           u32 gap, u32 tolerance, u32 priority, u32 ack_mtu)
1358 {
1359         struct sk_buff *buf = NULL;
1360         struct tipc_msg *msg = l_ptr->pmsg;
1361         u32 msg_size = sizeof(l_ptr->proto_msg);
1362         int r_flag;
1363
1364         /* Don't send protocol message during link changeover */
1365         if (l_ptr->exp_msg_count)
1366                 return;
1367
1368         /* Abort non-RESET send if communication with node is prohibited */
1369         if ((tipc_node_blocked(l_ptr->owner)) && (msg_typ != RESET_MSG))
1370                 return;
1371
1372         /* Create protocol message with "out-of-sequence" sequence number */
1373         msg_set_type(msg, msg_typ);
1374         msg_set_net_plane(msg, l_ptr->net_plane);
1375         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1376         msg_set_last_bcast(msg, tipc_bclink_get_last_sent(l_ptr->owner->net));
1377
1378         if (msg_typ == STATE_MSG) {
1379                 u32 next_sent = mod(l_ptr->next_out_no);
1380
1381                 if (!tipc_link_is_up(l_ptr))
1382                         return;
1383                 if (l_ptr->next_out)
1384                         next_sent = buf_seqno(l_ptr->next_out);
1385                 msg_set_next_sent(msg, next_sent);
1386                 if (!skb_queue_empty(&l_ptr->deferred_queue)) {
1387                         u32 rec = buf_seqno(skb_peek(&l_ptr->deferred_queue));
1388                         gap = mod(rec - mod(l_ptr->next_in_no));
1389                 }
1390                 msg_set_seq_gap(msg, gap);
1391                 if (gap)
1392                         l_ptr->stats.sent_nacks++;
1393                 msg_set_link_tolerance(msg, tolerance);
1394                 msg_set_linkprio(msg, priority);
1395                 msg_set_max_pkt(msg, ack_mtu);
1396                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1397                 msg_set_probe(msg, probe_msg != 0);
1398                 if (probe_msg) {
1399                         u32 mtu = l_ptr->max_pkt;
1400
1401                         if ((mtu < l_ptr->max_pkt_target) &&
1402                             link_working_working(l_ptr) &&
1403                             l_ptr->fsm_msg_cnt) {
1404                                 msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1405                                 if (l_ptr->max_pkt_probes == 10) {
1406                                         l_ptr->max_pkt_target = (msg_size - 4);
1407                                         l_ptr->max_pkt_probes = 0;
1408                                         msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1409                                 }
1410                                 l_ptr->max_pkt_probes++;
1411                         }
1412
1413                         l_ptr->stats.sent_probes++;
1414                 }
1415                 l_ptr->stats.sent_states++;
1416         } else {                /* RESET_MSG or ACTIVATE_MSG */
1417                 msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
1418                 msg_set_seq_gap(msg, 0);
1419                 msg_set_next_sent(msg, 1);
1420                 msg_set_probe(msg, 0);
1421                 msg_set_link_tolerance(msg, l_ptr->tolerance);
1422                 msg_set_linkprio(msg, l_ptr->priority);
1423                 msg_set_max_pkt(msg, l_ptr->max_pkt_target);
1424         }
1425
1426         r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
1427         msg_set_redundant_link(msg, r_flag);
1428         msg_set_linkprio(msg, l_ptr->priority);
1429         msg_set_size(msg, msg_size);
1430
1431         msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
1432
1433         buf = tipc_buf_acquire(msg_size);
1434         if (!buf)
1435                 return;
1436
1437         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
1438         buf->priority = TC_PRIO_CONTROL;
1439
1440         tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, buf,
1441                          &l_ptr->media_addr);
1442         l_ptr->unacked_window = 0;
1443         kfree_skb(buf);
1444 }
1445
1446 /*
1447  * Receive protocol message :
1448  * Note that network plane id propagates through the network, and may
1449  * change at any time. The node with lowest address rules
1450  */
1451 static void tipc_link_proto_rcv(struct tipc_link *l_ptr,
1452                                 struct sk_buff *buf)
1453 {
1454         u32 rec_gap = 0;
1455         u32 max_pkt_info;
1456         u32 max_pkt_ack;
1457         u32 msg_tol;
1458         struct tipc_msg *msg = buf_msg(buf);
1459
1460         /* Discard protocol message during link changeover */
1461         if (l_ptr->exp_msg_count)
1462                 goto exit;
1463
1464         if (l_ptr->net_plane != msg_net_plane(msg))
1465                 if (link_own_addr(l_ptr) > msg_prevnode(msg))
1466                         l_ptr->net_plane = msg_net_plane(msg);
1467
1468         switch (msg_type(msg)) {
1469
1470         case RESET_MSG:
1471                 if (!link_working_unknown(l_ptr) &&
1472                     (l_ptr->peer_session != INVALID_SESSION)) {
1473                         if (less_eq(msg_session(msg), l_ptr->peer_session))
1474                                 break; /* duplicate or old reset: ignore */
1475                 }
1476
1477                 if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
1478                                 link_working_unknown(l_ptr))) {
1479                         /*
1480                          * peer has lost contact -- don't allow peer's links
1481                          * to reactivate before we recognize loss & clean up
1482                          */
1483                         l_ptr->owner->action_flags |= TIPC_WAIT_OWN_LINKS_DOWN;
1484                 }
1485
1486                 link_state_event(l_ptr, RESET_MSG);
1487
1488                 /* fall thru' */
1489         case ACTIVATE_MSG:
1490                 /* Update link settings according other endpoint's values */
1491                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
1492
1493                 msg_tol = msg_link_tolerance(msg);
1494                 if (msg_tol > l_ptr->tolerance)
1495                         link_set_supervision_props(l_ptr, msg_tol);
1496
1497                 if (msg_linkprio(msg) > l_ptr->priority)
1498                         l_ptr->priority = msg_linkprio(msg);
1499
1500                 max_pkt_info = msg_max_pkt(msg);
1501                 if (max_pkt_info) {
1502                         if (max_pkt_info < l_ptr->max_pkt_target)
1503                                 l_ptr->max_pkt_target = max_pkt_info;
1504                         if (l_ptr->max_pkt > l_ptr->max_pkt_target)
1505                                 l_ptr->max_pkt = l_ptr->max_pkt_target;
1506                 } else {
1507                         l_ptr->max_pkt = l_ptr->max_pkt_target;
1508                 }
1509
1510                 /* Synchronize broadcast link info, if not done previously */
1511                 if (!tipc_node_is_up(l_ptr->owner)) {
1512                         l_ptr->owner->bclink.last_sent =
1513                                 l_ptr->owner->bclink.last_in =
1514                                 msg_last_bcast(msg);
1515                         l_ptr->owner->bclink.oos_state = 0;
1516                 }
1517
1518                 l_ptr->peer_session = msg_session(msg);
1519                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
1520
1521                 if (msg_type(msg) == ACTIVATE_MSG)
1522                         link_state_event(l_ptr, ACTIVATE_MSG);
1523                 break;
1524         case STATE_MSG:
1525
1526                 msg_tol = msg_link_tolerance(msg);
1527                 if (msg_tol)
1528                         link_set_supervision_props(l_ptr, msg_tol);
1529
1530                 if (msg_linkprio(msg) &&
1531                     (msg_linkprio(msg) != l_ptr->priority)) {
1532                         pr_debug("%s<%s>, priority change %u->%u\n",
1533                                  link_rst_msg, l_ptr->name,
1534                                  l_ptr->priority, msg_linkprio(msg));
1535                         l_ptr->priority = msg_linkprio(msg);
1536                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
1537                         break;
1538                 }
1539
1540                 /* Record reception; force mismatch at next timeout: */
1541                 l_ptr->checkpoint--;
1542
1543                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1544                 l_ptr->stats.recv_states++;
1545                 if (link_reset_unknown(l_ptr))
1546                         break;
1547
1548                 if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
1549                         rec_gap = mod(msg_next_sent(msg) -
1550                                       mod(l_ptr->next_in_no));
1551                 }
1552
1553                 max_pkt_ack = msg_max_pkt(msg);
1554                 if (max_pkt_ack > l_ptr->max_pkt) {
1555                         l_ptr->max_pkt = max_pkt_ack;
1556                         l_ptr->max_pkt_probes = 0;
1557                 }
1558
1559                 max_pkt_ack = 0;
1560                 if (msg_probe(msg)) {
1561                         l_ptr->stats.recv_probes++;
1562                         if (msg_size(msg) > sizeof(l_ptr->proto_msg))
1563                                 max_pkt_ack = msg_size(msg);
1564                 }
1565
1566                 /* Protocol message before retransmits, reduce loss risk */
1567                 if (l_ptr->owner->bclink.recv_permitted)
1568                         tipc_bclink_update_link_state(l_ptr->owner,
1569                                                       msg_last_bcast(msg));
1570
1571                 if (rec_gap || (msg_probe(msg))) {
1572                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, rec_gap, 0,
1573                                              0, max_pkt_ack);
1574                 }
1575                 if (msg_seq_gap(msg)) {
1576                         l_ptr->stats.recv_nacks++;
1577                         tipc_link_retransmit(l_ptr, skb_peek(&l_ptr->outqueue),
1578                                              msg_seq_gap(msg));
1579                 }
1580                 break;
1581         }
1582 exit:
1583         kfree_skb(buf);
1584 }
1585
1586
1587 /* tipc_link_tunnel_xmit(): Tunnel one packet via a link belonging to
1588  * a different bearer. Owner node is locked.
1589  */
1590 static void tipc_link_tunnel_xmit(struct tipc_link *l_ptr,
1591                                   struct tipc_msg *tunnel_hdr,
1592                                   struct tipc_msg *msg,
1593                                   u32 selector)
1594 {
1595         struct tipc_link *tunnel;
1596         struct sk_buff *skb;
1597         u32 length = msg_size(msg);
1598
1599         tunnel = l_ptr->owner->active_links[selector & 1];
1600         if (!tipc_link_is_up(tunnel)) {
1601                 pr_warn("%stunnel link no longer available\n", link_co_err);
1602                 return;
1603         }
1604         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
1605         skb = tipc_buf_acquire(length + INT_H_SIZE);
1606         if (!skb) {
1607                 pr_warn("%sunable to send tunnel msg\n", link_co_err);
1608                 return;
1609         }
1610         skb_copy_to_linear_data(skb, tunnel_hdr, INT_H_SIZE);
1611         skb_copy_to_linear_data_offset(skb, INT_H_SIZE, msg, length);
1612         __tipc_link_xmit_skb(tunnel, skb);
1613 }
1614
1615
1616 /* tipc_link_failover_send_queue(): A link has gone down, but a second
1617  * link is still active. We can do failover. Tunnel the failing link's
1618  * whole send queue via the remaining link. This way, we don't lose
1619  * any packets, and sequence order is preserved for subsequent traffic
1620  * sent over the remaining link. Owner node is locked.
1621  */
1622 void tipc_link_failover_send_queue(struct tipc_link *l_ptr)
1623 {
1624         u32 msgcount = skb_queue_len(&l_ptr->outqueue);
1625         struct tipc_link *tunnel = l_ptr->owner->active_links[0];
1626         struct tipc_msg tunnel_hdr;
1627         struct sk_buff *skb;
1628         int split_bundles;
1629
1630         if (!tunnel)
1631                 return;
1632
1633         tipc_msg_init(link_own_addr(l_ptr), &tunnel_hdr, CHANGEOVER_PROTOCOL,
1634                       ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
1635         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
1636         msg_set_msgcnt(&tunnel_hdr, msgcount);
1637
1638         if (skb_queue_empty(&l_ptr->outqueue)) {
1639                 skb = tipc_buf_acquire(INT_H_SIZE);
1640                 if (skb) {
1641                         skb_copy_to_linear_data(skb, &tunnel_hdr, INT_H_SIZE);
1642                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
1643                         __tipc_link_xmit_skb(tunnel, skb);
1644                 } else {
1645                         pr_warn("%sunable to send changeover msg\n",
1646                                 link_co_err);
1647                 }
1648                 return;
1649         }
1650
1651         split_bundles = (l_ptr->owner->active_links[0] !=
1652                          l_ptr->owner->active_links[1]);
1653
1654         skb_queue_walk(&l_ptr->outqueue, skb) {
1655                 struct tipc_msg *msg = buf_msg(skb);
1656
1657                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
1658                         struct tipc_msg *m = msg_get_wrapped(msg);
1659                         unchar *pos = (unchar *)m;
1660
1661                         msgcount = msg_msgcnt(msg);
1662                         while (msgcount--) {
1663                                 msg_set_seqno(m, msg_seqno(msg));
1664                                 tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, m,
1665                                                       msg_link_selector(m));
1666                                 pos += align(msg_size(m));
1667                                 m = (struct tipc_msg *)pos;
1668                         }
1669                 } else {
1670                         tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, msg,
1671                                               msg_link_selector(msg));
1672                 }
1673         }
1674 }
1675
1676 /* tipc_link_dup_queue_xmit(): A second link has become active. Tunnel a
1677  * duplicate of the first link's send queue via the new link. This way, we
1678  * are guaranteed that currently queued packets from a socket are delivered
1679  * before future traffic from the same socket, even if this is using the
1680  * new link. The last arriving copy of each duplicate packet is dropped at
1681  * the receiving end by the regular protocol check, so packet cardinality
1682  * and sequence order is preserved per sender/receiver socket pair.
1683  * Owner node is locked.
1684  */
1685 void tipc_link_dup_queue_xmit(struct tipc_link *l_ptr,
1686                               struct tipc_link *tunnel)
1687 {
1688         struct sk_buff *skb;
1689         struct tipc_msg tunnel_hdr;
1690
1691         tipc_msg_init(link_own_addr(l_ptr), &tunnel_hdr, CHANGEOVER_PROTOCOL,
1692                       DUPLICATE_MSG, INT_H_SIZE, l_ptr->addr);
1693         msg_set_msgcnt(&tunnel_hdr, skb_queue_len(&l_ptr->outqueue));
1694         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
1695         skb_queue_walk(&l_ptr->outqueue, skb) {
1696                 struct sk_buff *outskb;
1697                 struct tipc_msg *msg = buf_msg(skb);
1698                 u32 length = msg_size(msg);
1699
1700                 if (msg_user(msg) == MSG_BUNDLER)
1701                         msg_set_type(msg, CLOSED_MSG);
1702                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));   /* Update */
1703                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1704                 msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
1705                 outskb = tipc_buf_acquire(length + INT_H_SIZE);
1706                 if (outskb == NULL) {
1707                         pr_warn("%sunable to send duplicate msg\n",
1708                                 link_co_err);
1709                         return;
1710                 }
1711                 skb_copy_to_linear_data(outskb, &tunnel_hdr, INT_H_SIZE);
1712                 skb_copy_to_linear_data_offset(outskb, INT_H_SIZE, skb->data,
1713                                                length);
1714                 __tipc_link_xmit_skb(tunnel, outskb);
1715                 if (!tipc_link_is_up(l_ptr))
1716                         return;
1717         }
1718 }
1719
1720 /**
1721  * buf_extract - extracts embedded TIPC message from another message
1722  * @skb: encapsulating message buffer
1723  * @from_pos: offset to extract from
1724  *
1725  * Returns a new message buffer containing an embedded message.  The
1726  * encapsulating buffer is left unchanged.
1727  */
1728 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
1729 {
1730         struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
1731         u32 size = msg_size(msg);
1732         struct sk_buff *eb;
1733
1734         eb = tipc_buf_acquire(size);
1735         if (eb)
1736                 skb_copy_to_linear_data(eb, msg, size);
1737         return eb;
1738 }
1739
1740 /* tipc_link_dup_rcv(): Receive a tunnelled DUPLICATE_MSG packet.
1741  * Owner node is locked.
1742  */
1743 static void tipc_link_dup_rcv(struct tipc_link *l_ptr,
1744                               struct sk_buff *t_buf)
1745 {
1746         struct sk_buff *buf;
1747
1748         if (!tipc_link_is_up(l_ptr))
1749                 return;
1750
1751         buf = buf_extract(t_buf, INT_H_SIZE);
1752         if (buf == NULL) {
1753                 pr_warn("%sfailed to extract inner dup pkt\n", link_co_err);
1754                 return;
1755         }
1756
1757         /* Add buffer to deferred queue, if applicable: */
1758         link_handle_out_of_seq_msg(l_ptr, buf);
1759 }
1760
1761 /*  tipc_link_failover_rcv(): Receive a tunnelled ORIGINAL_MSG packet
1762  *  Owner node is locked.
1763  */
1764 static struct sk_buff *tipc_link_failover_rcv(struct tipc_link *l_ptr,
1765                                               struct sk_buff *t_buf)
1766 {
1767         struct tipc_msg *t_msg = buf_msg(t_buf);
1768         struct sk_buff *buf = NULL;
1769         struct tipc_msg *msg;
1770
1771         if (tipc_link_is_up(l_ptr))
1772                 tipc_link_reset(l_ptr);
1773
1774         /* First failover packet? */
1775         if (l_ptr->exp_msg_count == START_CHANGEOVER)
1776                 l_ptr->exp_msg_count = msg_msgcnt(t_msg);
1777
1778         /* Should there be an inner packet? */
1779         if (l_ptr->exp_msg_count) {
1780                 l_ptr->exp_msg_count--;
1781                 buf = buf_extract(t_buf, INT_H_SIZE);
1782                 if (buf == NULL) {
1783                         pr_warn("%sno inner failover pkt\n", link_co_err);
1784                         goto exit;
1785                 }
1786                 msg = buf_msg(buf);
1787
1788                 if (less(msg_seqno(msg), l_ptr->reset_checkpoint)) {
1789                         kfree_skb(buf);
1790                         buf = NULL;
1791                         goto exit;
1792                 }
1793                 if (msg_user(msg) == MSG_FRAGMENTER) {
1794                         l_ptr->stats.recv_fragments++;
1795                         tipc_buf_append(&l_ptr->reasm_buf, &buf);
1796                 }
1797         }
1798 exit:
1799         if ((!l_ptr->exp_msg_count) && (l_ptr->flags & LINK_STOPPED))
1800                 tipc_link_delete(l_ptr);
1801         return buf;
1802 }
1803
1804 /*  tipc_link_tunnel_rcv(): Receive a tunnelled packet, sent
1805  *  via other link as result of a failover (ORIGINAL_MSG) or
1806  *  a new active link (DUPLICATE_MSG). Failover packets are
1807  *  returned to the active link for delivery upwards.
1808  *  Owner node is locked.
1809  */
1810 static int tipc_link_tunnel_rcv(struct tipc_node *n_ptr,
1811                                 struct sk_buff **buf)
1812 {
1813         struct sk_buff *t_buf = *buf;
1814         struct tipc_link *l_ptr;
1815         struct tipc_msg *t_msg = buf_msg(t_buf);
1816         u32 bearer_id = msg_bearer_id(t_msg);
1817
1818         *buf = NULL;
1819
1820         if (bearer_id >= MAX_BEARERS)
1821                 goto exit;
1822
1823         l_ptr = n_ptr->links[bearer_id];
1824         if (!l_ptr)
1825                 goto exit;
1826
1827         if (msg_type(t_msg) == DUPLICATE_MSG)
1828                 tipc_link_dup_rcv(l_ptr, t_buf);
1829         else if (msg_type(t_msg) == ORIGINAL_MSG)
1830                 *buf = tipc_link_failover_rcv(l_ptr, t_buf);
1831         else
1832                 pr_warn("%sunknown tunnel pkt received\n", link_co_err);
1833 exit:
1834         kfree_skb(t_buf);
1835         return *buf != NULL;
1836 }
1837
1838 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tol)
1839 {
1840         unsigned long intv = ((tol / 4) > 500) ? 500 : tol / 4;
1841
1842         if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1843                 return;
1844
1845         l_ptr->tolerance = tol;
1846         l_ptr->cont_intv = msecs_to_jiffies(intv);
1847         l_ptr->abort_limit = tol / (jiffies_to_msecs(l_ptr->cont_intv) / 4);
1848 }
1849
1850 void tipc_link_set_queue_limits(struct tipc_link *l_ptr, u32 window)
1851 {
1852         /* Data messages from this node, inclusive FIRST_FRAGM */
1853         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE] = window;
1854         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE] = (window / 3) * 4;
1855         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE] = (window / 3) * 5;
1856         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE] = (window / 3) * 6;
1857         /* Transiting data messages,inclusive FIRST_FRAGM */
1858         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE + 4] = 300;
1859         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE + 4] = 600;
1860         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE + 4] = 900;
1861         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE + 4] = 1200;
1862         l_ptr->queue_limit[CONN_MANAGER] = 1200;
1863         l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
1864         l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
1865         /* FRAGMENT and LAST_FRAGMENT packets */
1866         l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
1867 }
1868
1869 /* tipc_link_find_owner - locate owner node of link by link's name
1870  * @net: the applicable net namespace
1871  * @name: pointer to link name string
1872  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1873  *
1874  * Returns pointer to node owning the link, or 0 if no matching link is found.
1875  */
1876 static struct tipc_node *tipc_link_find_owner(struct net *net,
1877                                               const char *link_name,
1878                                               unsigned int *bearer_id)
1879 {
1880         struct tipc_net *tn = net_generic(net, tipc_net_id);
1881         struct tipc_link *l_ptr;
1882         struct tipc_node *n_ptr;
1883         struct tipc_node *found_node = NULL;
1884         int i;
1885
1886         *bearer_id = 0;
1887         rcu_read_lock();
1888         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
1889                 tipc_node_lock(n_ptr);
1890                 for (i = 0; i < MAX_BEARERS; i++) {
1891                         l_ptr = n_ptr->links[i];
1892                         if (l_ptr && !strcmp(l_ptr->name, link_name)) {
1893                                 *bearer_id = i;
1894                                 found_node = n_ptr;
1895                                 break;
1896                         }
1897                 }
1898                 tipc_node_unlock(n_ptr);
1899                 if (found_node)
1900                         break;
1901         }
1902         rcu_read_unlock();
1903
1904         return found_node;
1905 }
1906
1907 /**
1908  * link_reset_statistics - reset link statistics
1909  * @l_ptr: pointer to link
1910  */
1911 static void link_reset_statistics(struct tipc_link *l_ptr)
1912 {
1913         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
1914         l_ptr->stats.sent_info = l_ptr->next_out_no;
1915         l_ptr->stats.recv_info = l_ptr->next_in_no;
1916 }
1917
1918 static void link_print(struct tipc_link *l_ptr, const char *str)
1919 {
1920         struct tipc_net *tn = net_generic(l_ptr->owner->net, tipc_net_id);
1921         struct tipc_bearer *b_ptr;
1922
1923         rcu_read_lock();
1924         b_ptr = rcu_dereference_rtnl(tn->bearer_list[l_ptr->bearer_id]);
1925         if (b_ptr)
1926                 pr_info("%s Link %x<%s>:", str, l_ptr->addr, b_ptr->name);
1927         rcu_read_unlock();
1928
1929         if (link_working_unknown(l_ptr))
1930                 pr_cont(":WU\n");
1931         else if (link_reset_reset(l_ptr))
1932                 pr_cont(":RR\n");
1933         else if (link_reset_unknown(l_ptr))
1934                 pr_cont(":RU\n");
1935         else if (link_working_working(l_ptr))
1936                 pr_cont(":WW\n");
1937         else
1938                 pr_cont("\n");
1939 }
1940
1941 /* Parse and validate nested (link) properties valid for media, bearer and link
1942  */
1943 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1944 {
1945         int err;
1946
1947         err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1948                                tipc_nl_prop_policy);
1949         if (err)
1950                 return err;
1951
1952         if (props[TIPC_NLA_PROP_PRIO]) {
1953                 u32 prio;
1954
1955                 prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1956                 if (prio > TIPC_MAX_LINK_PRI)
1957                         return -EINVAL;
1958         }
1959
1960         if (props[TIPC_NLA_PROP_TOL]) {
1961                 u32 tol;
1962
1963                 tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1964                 if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1965                         return -EINVAL;
1966         }
1967
1968         if (props[TIPC_NLA_PROP_WIN]) {
1969                 u32 win;
1970
1971                 win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1972                 if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1973                         return -EINVAL;
1974         }
1975
1976         return 0;
1977 }
1978
1979 int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
1980 {
1981         int err;
1982         int res = 0;
1983         int bearer_id;
1984         char *name;
1985         struct tipc_link *link;
1986         struct tipc_node *node;
1987         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1988         struct net *net = sock_net(skb->sk);
1989
1990         if (!info->attrs[TIPC_NLA_LINK])
1991                 return -EINVAL;
1992
1993         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1994                                info->attrs[TIPC_NLA_LINK],
1995                                tipc_nl_link_policy);
1996         if (err)
1997                 return err;
1998
1999         if (!attrs[TIPC_NLA_LINK_NAME])
2000                 return -EINVAL;
2001
2002         name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
2003
2004         node = tipc_link_find_owner(net, name, &bearer_id);
2005         if (!node)
2006                 return -EINVAL;
2007
2008         tipc_node_lock(node);
2009
2010         link = node->links[bearer_id];
2011         if (!link) {
2012                 res = -EINVAL;
2013                 goto out;
2014         }
2015
2016         if (attrs[TIPC_NLA_LINK_PROP]) {
2017                 struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
2018
2019                 err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
2020                                               props);
2021                 if (err) {
2022                         res = err;
2023                         goto out;
2024                 }
2025
2026                 if (props[TIPC_NLA_PROP_TOL]) {
2027                         u32 tol;
2028
2029                         tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
2030                         link_set_supervision_props(link, tol);
2031                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0, 0);
2032                 }
2033                 if (props[TIPC_NLA_PROP_PRIO]) {
2034                         u32 prio;
2035
2036                         prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
2037                         link->priority = prio;
2038                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, 0, prio, 0);
2039                 }
2040                 if (props[TIPC_NLA_PROP_WIN]) {
2041                         u32 win;
2042
2043                         win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2044                         tipc_link_set_queue_limits(link, win);
2045                 }
2046         }
2047
2048 out:
2049         tipc_node_unlock(node);
2050
2051         return res;
2052 }
2053
2054 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
2055 {
2056         int i;
2057         struct nlattr *stats;
2058
2059         struct nla_map {
2060                 u32 key;
2061                 u32 val;
2062         };
2063
2064         struct nla_map map[] = {
2065                 {TIPC_NLA_STATS_RX_INFO, s->recv_info},
2066                 {TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
2067                 {TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
2068                 {TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
2069                 {TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
2070                 {TIPC_NLA_STATS_TX_INFO, s->sent_info},
2071                 {TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
2072                 {TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
2073                 {TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
2074                 {TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
2075                 {TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
2076                         s->msg_length_counts : 1},
2077                 {TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
2078                 {TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
2079                 {TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
2080                 {TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
2081                 {TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
2082                 {TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
2083                 {TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
2084                 {TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
2085                 {TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
2086                 {TIPC_NLA_STATS_RX_STATES, s->recv_states},
2087                 {TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
2088                 {TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
2089                 {TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
2090                 {TIPC_NLA_STATS_TX_STATES, s->sent_states},
2091                 {TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
2092                 {TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
2093                 {TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
2094                 {TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
2095                 {TIPC_NLA_STATS_DUPLICATES, s->duplicates},
2096                 {TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
2097                 {TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
2098                 {TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
2099                         (s->accu_queue_sz / s->queue_sz_counts) : 0}
2100         };
2101
2102         stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
2103         if (!stats)
2104                 return -EMSGSIZE;
2105
2106         for (i = 0; i <  ARRAY_SIZE(map); i++)
2107                 if (nla_put_u32(skb, map[i].key, map[i].val))
2108                         goto msg_full;
2109
2110         nla_nest_end(skb, stats);
2111
2112         return 0;
2113 msg_full:
2114         nla_nest_cancel(skb, stats);
2115
2116         return -EMSGSIZE;
2117 }
2118
2119 /* Caller should hold appropriate locks to protect the link */
2120 static int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2121                               struct tipc_link *link)
2122 {
2123         int err;
2124         void *hdr;
2125         struct nlattr *attrs;
2126         struct nlattr *prop;
2127         struct tipc_net *tn = net_generic(net, tipc_net_id);
2128
2129         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2130                           NLM_F_MULTI, TIPC_NL_LINK_GET);
2131         if (!hdr)
2132                 return -EMSGSIZE;
2133
2134         attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
2135         if (!attrs)
2136                 goto msg_full;
2137
2138         if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2139                 goto attr_msg_full;
2140         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
2141                         tipc_cluster_mask(tn->own_addr)))
2142                 goto attr_msg_full;
2143         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->max_pkt))
2144                 goto attr_msg_full;
2145         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->next_in_no))
2146                 goto attr_msg_full;
2147         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->next_out_no))
2148                 goto attr_msg_full;
2149
2150         if (tipc_link_is_up(link))
2151                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2152                         goto attr_msg_full;
2153         if (tipc_link_is_active(link))
2154                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2155                         goto attr_msg_full;
2156
2157         prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
2158         if (!prop)
2159                 goto attr_msg_full;
2160         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2161                 goto prop_msg_full;
2162         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2163                 goto prop_msg_full;
2164         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2165                         link->queue_limit[TIPC_LOW_IMPORTANCE]))
2166                 goto prop_msg_full;
2167         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2168                 goto prop_msg_full;
2169         nla_nest_end(msg->skb, prop);
2170
2171         err = __tipc_nl_add_stats(msg->skb, &link->stats);
2172         if (err)
2173                 goto attr_msg_full;
2174
2175         nla_nest_end(msg->skb, attrs);
2176         genlmsg_end(msg->skb, hdr);
2177
2178         return 0;
2179
2180 prop_msg_full:
2181         nla_nest_cancel(msg->skb, prop);
2182 attr_msg_full:
2183         nla_nest_cancel(msg->skb, attrs);
2184 msg_full:
2185         genlmsg_cancel(msg->skb, hdr);
2186
2187         return -EMSGSIZE;
2188 }
2189
2190 /* Caller should hold node lock  */
2191 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
2192                                     struct tipc_node *node, u32 *prev_link)
2193 {
2194         u32 i;
2195         int err;
2196
2197         for (i = *prev_link; i < MAX_BEARERS; i++) {
2198                 *prev_link = i;
2199
2200                 if (!node->links[i])
2201                         continue;
2202
2203                 err = __tipc_nl_add_link(net, msg, node->links[i]);
2204                 if (err)
2205                         return err;
2206         }
2207         *prev_link = 0;
2208
2209         return 0;
2210 }
2211
2212 int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
2213 {
2214         struct net *net = sock_net(skb->sk);
2215         struct tipc_net *tn = net_generic(net, tipc_net_id);
2216         struct tipc_node *node;
2217         struct tipc_nl_msg msg;
2218         u32 prev_node = cb->args[0];
2219         u32 prev_link = cb->args[1];
2220         int done = cb->args[2];
2221         int err;
2222
2223         if (done)
2224                 return 0;
2225
2226         msg.skb = skb;
2227         msg.portid = NETLINK_CB(cb->skb).portid;
2228         msg.seq = cb->nlh->nlmsg_seq;
2229
2230         rcu_read_lock();
2231
2232         if (prev_node) {
2233                 node = tipc_node_find(net, prev_node);
2234                 if (!node) {
2235                         /* We never set seq or call nl_dump_check_consistent()
2236                          * this means that setting prev_seq here will cause the
2237                          * consistence check to fail in the netlink callback
2238                          * handler. Resulting in the last NLMSG_DONE message
2239                          * having the NLM_F_DUMP_INTR flag set.
2240                          */
2241                         cb->prev_seq = 1;
2242                         goto out;
2243                 }
2244
2245                 list_for_each_entry_continue_rcu(node, &tn->node_list,
2246                                                  list) {
2247                         tipc_node_lock(node);
2248                         err = __tipc_nl_add_node_links(net, &msg, node,
2249                                                        &prev_link);
2250                         tipc_node_unlock(node);
2251                         if (err)
2252                                 goto out;
2253
2254                         prev_node = node->addr;
2255                 }
2256         } else {
2257                 err = tipc_nl_add_bc_link(net, &msg);
2258                 if (err)
2259                         goto out;
2260
2261                 list_for_each_entry_rcu(node, &tn->node_list, list) {
2262                         tipc_node_lock(node);
2263                         err = __tipc_nl_add_node_links(net, &msg, node,
2264                                                        &prev_link);
2265                         tipc_node_unlock(node);
2266                         if (err)
2267                                 goto out;
2268
2269                         prev_node = node->addr;
2270                 }
2271         }
2272         done = 1;
2273 out:
2274         rcu_read_unlock();
2275
2276         cb->args[0] = prev_node;
2277         cb->args[1] = prev_link;
2278         cb->args[2] = done;
2279
2280         return skb->len;
2281 }
2282
2283 int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
2284 {
2285         struct net *net = genl_info_net(info);
2286         struct sk_buff *ans_skb;
2287         struct tipc_nl_msg msg;
2288         struct tipc_link *link;
2289         struct tipc_node *node;
2290         char *name;
2291         int bearer_id;
2292         int err;
2293
2294         if (!info->attrs[TIPC_NLA_LINK_NAME])
2295                 return -EINVAL;
2296
2297         name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
2298         node = tipc_link_find_owner(net, name, &bearer_id);
2299         if (!node)
2300                 return -EINVAL;
2301
2302         ans_skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
2303         if (!ans_skb)
2304                 return -ENOMEM;
2305
2306         msg.skb = ans_skb;
2307         msg.portid = info->snd_portid;
2308         msg.seq = info->snd_seq;
2309
2310         tipc_node_lock(node);
2311         link = node->links[bearer_id];
2312         if (!link) {
2313                 err = -EINVAL;
2314                 goto err_out;
2315         }
2316
2317         err = __tipc_nl_add_link(net, &msg, link);
2318         if (err)
2319                 goto err_out;
2320
2321         tipc_node_unlock(node);
2322
2323         return genlmsg_reply(ans_skb, info);
2324
2325 err_out:
2326         tipc_node_unlock(node);
2327         nlmsg_free(ans_skb);
2328
2329         return err;
2330 }
2331
2332 int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
2333 {
2334         int err;
2335         char *link_name;
2336         unsigned int bearer_id;
2337         struct tipc_link *link;
2338         struct tipc_node *node;
2339         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
2340         struct net *net = sock_net(skb->sk);
2341
2342         if (!info->attrs[TIPC_NLA_LINK])
2343                 return -EINVAL;
2344
2345         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
2346                                info->attrs[TIPC_NLA_LINK],
2347                                tipc_nl_link_policy);
2348         if (err)
2349                 return err;
2350
2351         if (!attrs[TIPC_NLA_LINK_NAME])
2352                 return -EINVAL;
2353
2354         link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
2355
2356         if (strcmp(link_name, tipc_bclink_name) == 0) {
2357                 err = tipc_bclink_reset_stats(net);
2358                 if (err)
2359                         return err;
2360                 return 0;
2361         }
2362
2363         node = tipc_link_find_owner(net, link_name, &bearer_id);
2364         if (!node)
2365                 return -EINVAL;
2366
2367         tipc_node_lock(node);
2368
2369         link = node->links[bearer_id];
2370         if (!link) {
2371                 tipc_node_unlock(node);
2372                 return -EINVAL;
2373         }
2374
2375         link_reset_statistics(link);
2376
2377         tipc_node_unlock(node);
2378
2379         return 0;
2380 }