net/tipc/link.c

   1 /*
   2  * net/tipc/link.c: TIPC link code
   3  *
   4  * Copyright (c) 1996-2007, 2012-2016, Ericsson AB
   5  * Copyright (c) 2004-2007, 2010-2013, Wind River Systems
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the names of the copyright holders nor the names of its
  17  *    contributors may be used to endorse or promote products derived from
  18  *    this software without specific prior written permission.
  19  *
  20  * Alternatively, this software may be distributed under the terms of the
  21  * GNU General Public License ("GPL") version 2 as published by the Free
  22  * Software Foundation.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34  * POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include "core.h"
  38 #include "subscr.h"
  39 #include "link.h"
  40 #include "bcast.h"
  41 #include "socket.h"
  42 #include "name_distr.h"
  43 #include "discover.h"
  44 #include "netlink.h"
  45 #include "monitor.h"
  46 #include "trace.h"
  47 #include "crypto.h"
  48
  49 #include <linux/pkt_sched.h>
  50
  51 struct tipc_stats {
  52         u32 sent_pkts;
  53         u32 recv_pkts;
  54         u32 sent_states;
  55         u32 recv_states;
  56         u32 sent_probes;
  57         u32 recv_probes;
  58         u32 sent_nacks;
  59         u32 recv_nacks;
  60         u32 sent_acks;
  61         u32 sent_bundled;
  62         u32 sent_bundles;
  63         u32 recv_bundled;
  64         u32 recv_bundles;
  65         u32 retransmitted;
  66         u32 sent_fragmented;
  67         u32 sent_fragments;
  68         u32 recv_fragmented;
  69         u32 recv_fragments;
  70         u32 link_congs;         /* # port sends blocked by congestion */
  71         u32 deferred_recv;
  72         u32 duplicates;
  73         u32 max_queue_sz;       /* send queue size high water mark */
  74         u32 accu_queue_sz;      /* used for send queue size profiling */
  75         u32 queue_sz_counts;    /* used for send queue size profiling */
  76         u32 msg_length_counts;  /* used for message length profiling */
  77         u32 msg_lengths_total;  /* used for message length profiling */
  78         u32 msg_length_profile[7]; /* used for msg. length profiling */
  79 };
  80
  81 /**
  82  * struct tipc_link - TIPC link data structure
  83  * @addr: network address of link's peer node
  84  * @name: link name character string
  85  * @media_addr: media address to use when sending messages over link
  86  * @timer: link timer
  87  * @net: pointer to namespace struct
  88  * @refcnt: reference counter for permanent references (owner node & timer)
  89  * @peer_session: link session # being used by peer end of link
  90  * @peer_bearer_id: bearer id used by link's peer endpoint
  91  * @bearer_id: local bearer id used by link
  92  * @tolerance: minimum link continuity loss needed to reset link [in ms]
  93  * @abort_limit: # of unacknowledged continuity probes needed to reset link
  94  * @state: current state of link FSM
  95  * @peer_caps: bitmap describing capabilities of peer node
  96  * @silent_intv_cnt: # of timer intervals without any reception from peer
  97  * @proto_msg: template for control messages generated by link
  98  * @pmsg: convenience pointer to "proto_msg" field
  99  * @priority: current link priority
 100  * @net_plane: current link network plane ('A' through 'H')
 101  * @mon_state: cookie with information needed by link monitor
 102  * @backlog_limit: backlog queue congestion thresholds (indexed by importance)
 103  * @exp_msg_count: # of tunnelled messages expected during link changeover
 104  * @reset_rcv_checkpt: seq # of last acknowledged message at time of link reset
 105  * @mtu: current maximum packet size for this link
 106  * @advertised_mtu: advertised own mtu when link is being established
 107  * @transmitq: queue for sent, non-acked messages
 108  * @backlogq: queue for messages waiting to be sent
 109  * @snt_nxt: next sequence number to use for outbound messages
 110  * @ackers: # of peers that needs to ack each packet before it can be released
 111  * @acked: # last packet acked by a certain peer. Used for broadcast.
 112  * @rcv_nxt: next sequence number to expect for inbound messages
 113  * @deferred_queue: deferred queue saved OOS b'cast message received from node
 114  * @unacked_window: # of inbound messages rx'd without ack'ing back to peer
 115  * @inputq: buffer queue for messages to be delivered upwards
 116  * @namedq: buffer queue for name table messages to be delivered upwards
 117  * @next_out: ptr to first unsent outbound message in queue
 118  * @wakeupq: linked list of wakeup msgs waiting for link congestion to abate
 119  * @long_msg_seq_no: next identifier to use for outbound fragmented messages
 120  * @reasm_buf: head of partially reassembled inbound message fragments
 121  * @bc_rcvr: marks that this is a broadcast receiver link
 122  * @stats: collects statistics regarding link activity
 123  * @session: session to be used by link
 124  * @snd_nxt_state: next send seq number
 125  * @rcv_nxt_state: next rcv seq number
 126  * @in_session: have received ACTIVATE_MSG from peer
 127  * @active: link is active
 128  * @if_name: associated interface name
 129  * @rst_cnt: link reset counter
 130  * @drop_point: seq number for failover handling (FIXME)
 131  * @failover_reasm_skb: saved failover msg ptr (FIXME)
 132  * @failover_deferdq: deferred message queue for failover processing (FIXME)
 133  * @transmq: the link's transmit queue
 134  * @backlog: link's backlog by priority (importance)
 135  * @snd_nxt: next sequence number to be used
 136  * @rcv_unacked: # messages read by user, but not yet acked back to peer
 137  * @deferdq: deferred receive queue
 138  * @window: sliding window size for congestion handling
 139  * @min_win: minimal send window to be used by link
 140  * @ssthresh: slow start threshold for congestion handling
 141  * @max_win: maximal send window to be used by link
 142  * @cong_acks: congestion acks for congestion avoidance (FIXME)
 143  * @checkpoint: seq number for congestion window size handling
 144  * @reasm_tnlmsg: fragmentation/reassembly area for tunnel protocol message
 145  * @last_gap: last gap ack blocks for bcast (FIXME)
 146  * @last_ga: ptr to gap ack blocks
 147  * @bc_rcvlink: the peer specific link used for broadcast reception
 148  * @bc_sndlink: the namespace global link used for broadcast sending
 149  * @nack_state: bcast nack state
 150  * @bc_peer_is_up: peer has acked the bcast init msg
 151  */
 152 struct tipc_link {
 153         u32 addr;
 154         char name[TIPC_MAX_LINK_NAME];
 155         struct net *net;
 156
 157         /* Management and link supervision data */
 158         u16 peer_session;
 159         u16 session;
 160         u16 snd_nxt_state;
 161         u16 rcv_nxt_state;
 162         u32 peer_bearer_id;
 163         u32 bearer_id;
 164         u32 tolerance;
 165         u32 abort_limit;
 166         u32 state;
 167         u16 peer_caps;
 168         bool in_session;
 169         bool active;
 170         u32 silent_intv_cnt;
 171         char if_name[TIPC_MAX_IF_NAME];
 172         u32 priority;
 173         char net_plane;
 174         struct tipc_mon_state mon_state;
 175         u16 rst_cnt;
 176
 177         /* Failover/synch */
 178         u16 drop_point;
 179         struct sk_buff *failover_reasm_skb;
 180         struct sk_buff_head failover_deferdq;
 181
 182         /* Max packet negotiation */
 183         u16 mtu;
 184         u16 advertised_mtu;
 185
 186         /* Sending */
 187         struct sk_buff_head transmq;
 188         struct sk_buff_head backlogq;
 189         struct {
 190                 u16 len;
 191                 u16 limit;
 192                 struct sk_buff *target_bskb;
 193         } backlog[5];
 194         u16 snd_nxt;
 195
 196         /* Reception */
 197         u16 rcv_nxt;
 198         u32 rcv_unacked;
 199         struct sk_buff_head deferdq;
 200         struct sk_buff_head *inputq;
 201         struct sk_buff_head *namedq;
 202
 203         /* Congestion handling */
 204         struct sk_buff_head wakeupq;
 205         u16 window;
 206         u16 min_win;
 207         u16 ssthresh;
 208         u16 max_win;
 209         u16 cong_acks;
 210         u16 checkpoint;
 211
 212         /* Fragmentation/reassembly */
 213         struct sk_buff *reasm_buf;
 214         struct sk_buff *reasm_tnlmsg;
 215
 216         /* Broadcast */
 217         u16 ackers;
 218         u16 acked;
 219         u16 last_gap;
 220         struct tipc_gap_ack_blks *last_ga;
 221         struct tipc_link *bc_rcvlink;
 222         struct tipc_link *bc_sndlink;
 223         u8 nack_state;
 224         bool bc_peer_is_up;
 225
 226         /* Statistics */
 227         struct tipc_stats stats;
 228 };
 229
 230 /*
 231  * Error message prefixes
 232  */
 233 static const char *link_co_err = "Link tunneling error, ";
 234 static const char *link_rst_msg = "Resetting link ";
 235
 236 /* Send states for broadcast NACKs
 237  */
 238 enum {
 239         BC_NACK_SND_CONDITIONAL,
 240         BC_NACK_SND_UNCONDITIONAL,
 241         BC_NACK_SND_SUPPRESS,
 242 };
 243
 244 #define TIPC_BC_RETR_LIM  (jiffies + msecs_to_jiffies(10))
 245 #define TIPC_UC_RETR_TIME (jiffies + msecs_to_jiffies(1))
 246
 247 /* Link FSM states:
 248  */
 249 enum {
 250         LINK_ESTABLISHED     = 0xe,
 251         LINK_ESTABLISHING    = 0xe  << 4,
 252         LINK_RESET           = 0x1  << 8,
 253         LINK_RESETTING       = 0x2  << 12,
 254         LINK_PEER_RESET      = 0xd  << 16,
 255         LINK_FAILINGOVER     = 0xf  << 20,
 256         LINK_SYNCHING        = 0xc  << 24
 257 };
 258
 259 /* Link FSM state checking routines
 260  */
 261 static int link_is_up(struct tipc_link *l)
 262 {
 263         return l->state & (LINK_ESTABLISHED | LINK_SYNCHING);
 264 }
 265
 266 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
 267                                struct sk_buff_head *xmitq);
 268 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
 269                                       bool probe_reply, u16 rcvgap,
 270                                       int tolerance, int priority,
 271                                       struct sk_buff_head *xmitq);
 272 static void link_print(struct tipc_link *l, const char *str);
 273 static int tipc_link_build_nack_msg(struct tipc_link *l,
 274                                     struct sk_buff_head *xmitq);
 275 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
 276                                         struct sk_buff_head *xmitq);
 277 static u8 __tipc_build_gap_ack_blks(struct tipc_gap_ack_blks *ga,
 278                                     struct tipc_link *l, u8 start_index);
 279 static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr);
 280 static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
 281                                      u16 acked, u16 gap,
 282                                      struct tipc_gap_ack_blks *ga,
 283                                      struct sk_buff_head *xmitq,
 284                                      bool *retransmitted, int *rc);
 285 static void tipc_link_update_cwin(struct tipc_link *l, int released,
 286                                   bool retransmitted);
 287 /*
 288  *  Simple non-static link routines (i.e. referenced outside this file)
 289  */
 290 bool tipc_link_is_up(struct tipc_link *l)
 291 {
 292         return link_is_up(l);
 293 }
 294
 295 bool tipc_link_peer_is_down(struct tipc_link *l)
 296 {
 297         return l->state == LINK_PEER_RESET;
 298 }
 299
 300 bool tipc_link_is_reset(struct tipc_link *l)
 301 {
 302         return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
 303 }
 304
 305 bool tipc_link_is_establishing(struct tipc_link *l)
 306 {
 307         return l->state == LINK_ESTABLISHING;
 308 }
 309
 310 bool tipc_link_is_synching(struct tipc_link *l)
 311 {
 312         return l->state == LINK_SYNCHING;
 313 }
 314
 315 bool tipc_link_is_failingover(struct tipc_link *l)
 316 {
 317         return l->state == LINK_FAILINGOVER;
 318 }
 319
 320 bool tipc_link_is_blocked(struct tipc_link *l)
 321 {
 322         return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
 323 }
 324
 325 static bool link_is_bc_sndlink(struct tipc_link *l)
 326 {
 327         return !l->bc_sndlink;
 328 }
 329
 330 static bool link_is_bc_rcvlink(struct tipc_link *l)
 331 {
 332         return ((l->bc_rcvlink == l) && !link_is_bc_sndlink(l));
 333 }
 334
 335 void tipc_link_set_active(struct tipc_link *l, bool active)
 336 {
 337         l->active = active;
 338 }
 339
 340 u32 tipc_link_id(struct tipc_link *l)
 341 {
 342         return l->peer_bearer_id << 16 | l->bearer_id;
 343 }
 344
 345 int tipc_link_min_win(struct tipc_link *l)
 346 {
 347         return l->min_win;
 348 }
 349
 350 int tipc_link_max_win(struct tipc_link *l)
 351 {
 352         return l->max_win;
 353 }
 354
 355 int tipc_link_prio(struct tipc_link *l)
 356 {
 357         return l->priority;
 358 }
 359
 360 unsigned long tipc_link_tolerance(struct tipc_link *l)
 361 {
 362         return l->tolerance;
 363 }
 364
 365 struct sk_buff_head *tipc_link_inputq(struct tipc_link *l)
 366 {
 367         return l->inputq;
 368 }
 369
 370 char tipc_link_plane(struct tipc_link *l)
 371 {
 372         return l->net_plane;
 373 }
 374
 375 struct net *tipc_link_net(struct tipc_link *l)
 376 {
 377         return l->net;
 378 }
 379
 380 void tipc_link_update_caps(struct tipc_link *l, u16 capabilities)
 381 {
 382         l->peer_caps = capabilities;
 383 }
 384
 385 void tipc_link_add_bc_peer(struct tipc_link *snd_l,
 386                            struct tipc_link *uc_l,
 387                            struct sk_buff_head *xmitq)
 388 {
 389         struct tipc_link *rcv_l = uc_l->bc_rcvlink;
 390
 391         snd_l->ackers++;
 392         rcv_l->acked = snd_l->snd_nxt - 1;
 393         snd_l->state = LINK_ESTABLISHED;
 394         tipc_link_build_bc_init_msg(uc_l, xmitq);
 395 }
 396
 397 void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
 398                               struct tipc_link *rcv_l,
 399                               struct sk_buff_head *xmitq)
 400 {
 401         u16 ack = snd_l->snd_nxt - 1;
 402
 403         snd_l->ackers--;
 404         rcv_l->bc_peer_is_up = true;
 405         rcv_l->state = LINK_ESTABLISHED;
 406         tipc_link_bc_ack_rcv(rcv_l, ack, 0, NULL, xmitq, NULL);
 407         trace_tipc_link_reset(rcv_l, TIPC_DUMP_ALL, "bclink removed!");
 408         tipc_link_reset(rcv_l);
 409         rcv_l->state = LINK_RESET;
 410         if (!snd_l->ackers) {
 411                 trace_tipc_link_reset(snd_l, TIPC_DUMP_ALL, "zero ackers!");
 412                 tipc_link_reset(snd_l);
 413                 snd_l->state = LINK_RESET;
 414                 __skb_queue_purge(xmitq);
 415         }
 416 }
 417
 418 int tipc_link_bc_peers(struct tipc_link *l)
 419 {
 420         return l->ackers;
 421 }
 422
 423 static u16 link_bc_rcv_gap(struct tipc_link *l)
 424 {
 425         struct sk_buff *skb = skb_peek(&l->deferdq);
 426         u16 gap = 0;
 427
 428         if (more(l->snd_nxt, l->rcv_nxt))
 429                 gap = l->snd_nxt - l->rcv_nxt;
 430         if (skb)
 431                 gap = buf_seqno(skb) - l->rcv_nxt;
 432         return gap;
 433 }
 434
 435 void tipc_link_set_mtu(struct tipc_link *l, int mtu)
 436 {
 437         l->mtu = mtu;
 438 }
 439
 440 int tipc_link_mtu(struct tipc_link *l)
 441 {
 442         return l->mtu;
 443 }
 444
 445 int tipc_link_mss(struct tipc_link *l)
 446 {
 447 #ifdef CONFIG_TIPC_CRYPTO
 448         return l->mtu - INT_H_SIZE - EMSG_OVERHEAD;
 449 #else
 450         return l->mtu - INT_H_SIZE;
 451 #endif
 452 }
 453
 454 u16 tipc_link_rcv_nxt(struct tipc_link *l)
 455 {
 456         return l->rcv_nxt;
 457 }
 458
 459 u16 tipc_link_acked(struct tipc_link *l)
 460 {
 461         return l->acked;
 462 }
 463
 464 char *tipc_link_name(struct tipc_link *l)
 465 {
 466         return l->name;
 467 }
 468
 469 u32 tipc_link_state(struct tipc_link *l)
 470 {
 471         return l->state;
 472 }
 473
 474 /**
 475  * tipc_link_create - create a new link
 476  * @net: pointer to associated network namespace
 477  * @if_name: associated interface name
 478  * @bearer_id: id (index) of associated bearer
 479  * @tolerance: link tolerance to be used by link
 480  * @net_plane: network plane (A,B,c..) this link belongs to
 481  * @mtu: mtu to be advertised by link
 482  * @priority: priority to be used by link
 483  * @min_win: minimal send window to be used by link
 484  * @max_win: maximal send window to be used by link
 485  * @session: session to be used by link
 486  * @peer: node id of peer node
 487  * @peer_caps: bitmap describing peer node capabilities
 488  * @bc_sndlink: the namespace global link used for broadcast sending
 489  * @bc_rcvlink: the peer specific link used for broadcast reception
 490  * @inputq: queue to put messages ready for delivery
 491  * @namedq: queue to put binding table update messages ready for delivery
 492  * @link: return value, pointer to put the created link
 493  * @self: local unicast link id
 494  * @peer_id: 128-bit ID of peer
 495  *
 496  * Return: true if link was created, otherwise false
 497  */
 498 bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
 499                       int tolerance, char net_plane, u32 mtu, int priority,
 500                       u32 min_win, u32 max_win, u32 session, u32 self,
 501                       u32 peer, u8 *peer_id, u16 peer_caps,
 502                       struct tipc_link *bc_sndlink,
 503                       struct tipc_link *bc_rcvlink,
 504                       struct sk_buff_head *inputq,
 505                       struct sk_buff_head *namedq,
 506                       struct tipc_link **link)
 507 {
 508         char peer_str[NODE_ID_STR_LEN] = {0,};
 509         char self_str[NODE_ID_STR_LEN] = {0,};
 510         struct tipc_link *l;
 511
 512         l = kzalloc(sizeof(*l), GFP_ATOMIC);
 513         if (!l)
 514                 return false;
 515         *link = l;
 516         l->session = session;
 517
 518         /* Set link name for unicast links only */
 519         if (peer_id) {
 520                 tipc_nodeid2string(self_str, tipc_own_id(net));
 521                 if (strlen(self_str) > 16)
 522                         sprintf(self_str, "%x", self);
 523                 tipc_nodeid2string(peer_str, peer_id);
 524                 if (strlen(peer_str) > 16)
 525                         sprintf(peer_str, "%x", peer);
 526         }
 527         /* Peer i/f name will be completed by reset/activate message */
 528         snprintf(l->name, sizeof(l->name), "%s:%s-%s:unknown",
 529                  self_str, if_name, peer_str);
 530
 531         strcpy(l->if_name, if_name);
 532         l->addr = peer;
 533         l->peer_caps = peer_caps;
 534         l->net = net;
 535         l->in_session = false;
 536         l->bearer_id = bearer_id;
 537         l->tolerance = tolerance;
 538         if (bc_rcvlink)
 539                 bc_rcvlink->tolerance = tolerance;
 540         l->net_plane = net_plane;
 541         l->advertised_mtu = mtu;
 542         l->mtu = mtu;
 543         l->priority = priority;
 544         tipc_link_set_queue_limits(l, min_win, max_win);
 545         l->ackers = 1;
 546         l->bc_sndlink = bc_sndlink;
 547         l->bc_rcvlink = bc_rcvlink;
 548         l->inputq = inputq;
 549         l->namedq = namedq;
 550         l->state = LINK_RESETTING;
 551         __skb_queue_head_init(&l->transmq);
 552         __skb_queue_head_init(&l->backlogq);
 553         __skb_queue_head_init(&l->deferdq);
 554         __skb_queue_head_init(&l->failover_deferdq);
 555         skb_queue_head_init(&l->wakeupq);
 556         skb_queue_head_init(l->inputq);
 557         return true;
 558 }
 559
 560 /**
 561  * tipc_link_bc_create - create new link to be used for broadcast
 562  * @net: pointer to associated network namespace
 563  * @mtu: mtu to be used initially if no peers
 564  * @min_win: minimal send window to be used by link
 565  * @max_win: maximal send window to be used by link
 566  * @inputq: queue to put messages ready for delivery
 567  * @namedq: queue to put binding table update messages ready for delivery
 568  * @link: return value, pointer to put the created link
 569  * @ownnode: identity of own node
 570  * @peer: node id of peer node
 571  * @peer_id: 128-bit ID of peer
 572  * @peer_caps: bitmap describing peer node capabilities
 573  * @bc_sndlink: the namespace global link used for broadcast sending
 574  *
 575  * Return: true if link was created, otherwise false
 576  */
 577 bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer, u8 *peer_id,
 578                          int mtu, u32 min_win, u32 max_win, u16 peer_caps,
 579                          struct sk_buff_head *inputq,
 580                          struct sk_buff_head *namedq,
 581                          struct tipc_link *bc_sndlink,
 582                          struct tipc_link **link)
 583 {
 584         struct tipc_link *l;
 585
 586         if (!tipc_link_create(net, "", MAX_BEARERS, 0, 'Z', mtu, 0, min_win,
 587                               max_win, 0, ownnode, peer, NULL, peer_caps,
 588                               bc_sndlink, NULL, inputq, namedq, link))
 589                 return false;
 590
 591         l = *link;
 592         if (peer_id) {
 593                 char peer_str[NODE_ID_STR_LEN] = {0,};
 594
 595                 tipc_nodeid2string(peer_str, peer_id);
 596                 if (strlen(peer_str) > 16)
 597                         sprintf(peer_str, "%x", peer);
 598                 /* Broadcast receiver link name: "broadcast-link:<peer>" */
 599                 snprintf(l->name, sizeof(l->name), "%s:%s", tipc_bclink_name,
 600                          peer_str);
 601         } else {
 602                 strcpy(l->name, tipc_bclink_name);
 603         }
 604         trace_tipc_link_reset(l, TIPC_DUMP_ALL, "bclink created!");
 605         tipc_link_reset(l);
 606         l->state = LINK_RESET;
 607         l->ackers = 0;
 608         l->bc_rcvlink = l;
 609
 610         /* Broadcast send link is always up */
 611         if (link_is_bc_sndlink(l))
 612                 l->state = LINK_ESTABLISHED;
 613
 614         /* Disable replicast if even a single peer doesn't support it */
 615         if (link_is_bc_rcvlink(l) && !(peer_caps & TIPC_BCAST_RCAST))
 616                 tipc_bcast_toggle_rcast(net, false);
 617
 618         return true;
 619 }
 620
 621 /**
 622  * tipc_link_fsm_evt - link finite state machine
 623  * @l: pointer to link
 624  * @evt: state machine event to be processed
 625  */
 626 int tipc_link_fsm_evt(struct tipc_link *l, int evt)
 627 {
 628         int rc = 0;
 629         int old_state = l->state;
 630
 631         switch (l->state) {
 632         case LINK_RESETTING:
 633                 switch (evt) {
 634                 case LINK_PEER_RESET_EVT:
 635                         l->state = LINK_PEER_RESET;
 636                         break;
 637                 case LINK_RESET_EVT:
 638                         l->state = LINK_RESET;
 639                         break;
 640                 case LINK_FAILURE_EVT:
 641                 case LINK_FAILOVER_BEGIN_EVT:
 642                 case LINK_ESTABLISH_EVT:
 643                 case LINK_FAILOVER_END_EVT:
 644                 case LINK_SYNCH_BEGIN_EVT:
 645                 case LINK_SYNCH_END_EVT:
 646                 default:
 647                         goto illegal_evt;
 648                 }
 649                 break;
 650         case LINK_RESET:
 651                 switch (evt) {
 652                 case LINK_PEER_RESET_EVT:
 653                         l->state = LINK_ESTABLISHING;
 654                         break;
 655                 case LINK_FAILOVER_BEGIN_EVT:
 656                         l->state = LINK_FAILINGOVER;
 657                         break;
 658                 case LINK_FAILURE_EVT:
 659                 case LINK_RESET_EVT:
 660                 case LINK_ESTABLISH_EVT:
 661                 case LINK_FAILOVER_END_EVT:
 662                         break;
 663                 case LINK_SYNCH_BEGIN_EVT:
 664                 case LINK_SYNCH_END_EVT:
 665                 default:
 666                         goto illegal_evt;
 667                 }
 668                 break;
 669         case LINK_PEER_RESET:
 670                 switch (evt) {
 671                 case LINK_RESET_EVT:
 672                         l->state = LINK_ESTABLISHING;
 673                         break;
 674                 case LINK_PEER_RESET_EVT:
 675                 case LINK_ESTABLISH_EVT:
 676                 case LINK_FAILURE_EVT:
 677                         break;
 678                 case LINK_SYNCH_BEGIN_EVT:
 679                 case LINK_SYNCH_END_EVT:
 680                 case LINK_FAILOVER_BEGIN_EVT:
 681                 case LINK_FAILOVER_END_EVT:
 682                 default:
 683                         goto illegal_evt;
 684                 }
 685                 break;
 686         case LINK_FAILINGOVER:
 687                 switch (evt) {
 688                 case LINK_FAILOVER_END_EVT:
 689                         l->state = LINK_RESET;
 690                         break;
 691                 case LINK_PEER_RESET_EVT:
 692                 case LINK_RESET_EVT:
 693                 case LINK_ESTABLISH_EVT:
 694                 case LINK_FAILURE_EVT:
 695                         break;
 696                 case LINK_FAILOVER_BEGIN_EVT:
 697                 case LINK_SYNCH_BEGIN_EVT:
 698                 case LINK_SYNCH_END_EVT:
 699                 default:
 700                         goto illegal_evt;
 701                 }
 702                 break;
 703         case LINK_ESTABLISHING:
 704                 switch (evt) {
 705                 case LINK_ESTABLISH_EVT:
 706                         l->state = LINK_ESTABLISHED;
 707                         break;
 708                 case LINK_FAILOVER_BEGIN_EVT:
 709                         l->state = LINK_FAILINGOVER;
 710                         break;
 711                 case LINK_RESET_EVT:
 712                         l->state = LINK_RESET;
 713                         break;
 714                 case LINK_FAILURE_EVT:
 715                 case LINK_PEER_RESET_EVT:
 716                 case LINK_SYNCH_BEGIN_EVT:
 717                 case LINK_FAILOVER_END_EVT:
 718                         break;
 719                 case LINK_SYNCH_END_EVT:
 720                 default:
 721                         goto illegal_evt;
 722                 }
 723                 break;
 724         case LINK_ESTABLISHED:
 725                 switch (evt) {
 726                 case LINK_PEER_RESET_EVT:
 727                         l->state = LINK_PEER_RESET;
 728                         rc |= TIPC_LINK_DOWN_EVT;
 729                         break;
 730                 case LINK_FAILURE_EVT:
 731                         l->state = LINK_RESETTING;
 732                         rc |= TIPC_LINK_DOWN_EVT;
 733                         break;
 734                 case LINK_RESET_EVT:
 735                         l->state = LINK_RESET;
 736                         break;
 737                 case LINK_ESTABLISH_EVT:
 738                 case LINK_SYNCH_END_EVT:
 739                         break;
 740                 case LINK_SYNCH_BEGIN_EVT:
 741                         l->state = LINK_SYNCHING;
 742                         break;
 743                 case LINK_FAILOVER_BEGIN_EVT:
 744                 case LINK_FAILOVER_END_EVT:
 745                 default:
 746                         goto illegal_evt;
 747                 }
 748                 break;
 749         case LINK_SYNCHING:
 750                 switch (evt) {
 751                 case LINK_PEER_RESET_EVT:
 752                         l->state = LINK_PEER_RESET;
 753                         rc |= TIPC_LINK_DOWN_EVT;
 754                         break;
 755                 case LINK_FAILURE_EVT:
 756                         l->state = LINK_RESETTING;
 757                         rc |= TIPC_LINK_DOWN_EVT;
 758                         break;
 759                 case LINK_RESET_EVT:
 760                         l->state = LINK_RESET;
 761                         break;
 762                 case LINK_ESTABLISH_EVT:
 763                 case LINK_SYNCH_BEGIN_EVT:
 764                         break;
 765                 case LINK_SYNCH_END_EVT:
 766                         l->state = LINK_ESTABLISHED;
 767                         break;
 768                 case LINK_FAILOVER_BEGIN_EVT:
 769                 case LINK_FAILOVER_END_EVT:
 770                 default:
 771                         goto illegal_evt;
 772                 }
 773                 break;
 774         default:
 775                 pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
 776         }
 777         trace_tipc_link_fsm(l->name, old_state, l->state, evt);
 778         return rc;
 779 illegal_evt:
 780         pr_err("Illegal FSM event %x in state %x on link %s\n",
 781                evt, l->state, l->name);
 782         trace_tipc_link_fsm(l->name, old_state, l->state, evt);
 783         return rc;
 784 }
 785
 786 /* link_profile_stats - update statistical profiling of traffic
 787  */
 788 static void link_profile_stats(struct tipc_link *l)
 789 {
 790         struct sk_buff *skb;
 791         struct tipc_msg *msg;
 792         int length;
 793
 794         /* Update counters used in statistical profiling of send traffic */
 795         l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
 796         l->stats.queue_sz_counts++;
 797
 798         skb = skb_peek(&l->transmq);
 799         if (!skb)
 800                 return;
 801         msg = buf_msg(skb);
 802         length = msg_size(msg);
 803
 804         if (msg_user(msg) == MSG_FRAGMENTER) {
 805                 if (msg_type(msg) != FIRST_FRAGMENT)
 806                         return;
 807                 length = msg_size(msg_inner_hdr(msg));
 808         }
 809         l->stats.msg_lengths_total += length;
 810         l->stats.msg_length_counts++;
 811         if (length <= 64)
 812                 l->stats.msg_length_profile[0]++;
 813         else if (length <= 256)
 814                 l->stats.msg_length_profile[1]++;
 815         else if (length <= 1024)
 816                 l->stats.msg_length_profile[2]++;
 817         else if (length <= 4096)
 818                 l->stats.msg_length_profile[3]++;
 819         else if (length <= 16384)
 820                 l->stats.msg_length_profile[4]++;
 821         else if (length <= 32768)
 822                 l->stats.msg_length_profile[5]++;
 823         else
 824                 l->stats.msg_length_profile[6]++;
 825 }
 826
 827 /**
 828  * tipc_link_too_silent - check if link is "too silent"
 829  * @l: tipc link to be checked
 830  *
 831  * Return: true if the link 'silent_intv_cnt' is about to reach the
 832  * 'abort_limit' value, otherwise false
 833  */
 834 bool tipc_link_too_silent(struct tipc_link *l)
 835 {
 836         return (l->silent_intv_cnt + 2 > l->abort_limit);
 837 }
 838
 839 /* tipc_link_timeout - perform periodic task as instructed from node timeout
 840  */
 841 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
 842 {
 843         int mtyp = 0;
 844         int rc = 0;
 845         bool state = false;
 846         bool probe = false;
 847         bool setup = false;
 848         u16 bc_snt = l->bc_sndlink->snd_nxt - 1;
 849         u16 bc_acked = l->bc_rcvlink->acked;
 850         struct tipc_mon_state *mstate = &l->mon_state;
 851
 852         trace_tipc_link_timeout(l, TIPC_DUMP_NONE, " ");
 853         trace_tipc_link_too_silent(l, TIPC_DUMP_ALL, " ");
 854         switch (l->state) {
 855         case LINK_ESTABLISHED:
 856         case LINK_SYNCHING:
 857                 mtyp = STATE_MSG;
 858                 link_profile_stats(l);
 859                 tipc_mon_get_state(l->net, l->addr, mstate, l->bearer_id);
 860                 if (mstate->reset || (l->silent_intv_cnt > l->abort_limit))
 861                         return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
 862                 state = bc_acked != bc_snt;
 863                 state |= l->bc_rcvlink->rcv_unacked;
 864                 state |= l->rcv_unacked;
 865                 state |= !skb_queue_empty(&l->transmq);
 866                 probe = mstate->probing;
 867                 probe |= l->silent_intv_cnt;
 868                 if (probe || mstate->monitoring)
 869                         l->silent_intv_cnt++;
 870                 probe |= !skb_queue_empty(&l->deferdq);
 871                 if (l->snd_nxt == l->checkpoint) {
 872                         tipc_link_update_cwin(l, 0, 0);
 873                         probe = true;
 874                 }
 875                 l->checkpoint = l->snd_nxt;
 876                 break;
 877         case LINK_RESET:
 878                 setup = l->rst_cnt++ <= 4;
 879                 setup |= !(l->rst_cnt % 16);
 880                 mtyp = RESET_MSG;
 881                 break;
 882         case LINK_ESTABLISHING:
 883                 setup = true;
 884                 mtyp = ACTIVATE_MSG;
 885                 break;
 886         case LINK_PEER_RESET:
 887         case LINK_RESETTING:
 888         case LINK_FAILINGOVER:
 889                 break;
 890         default:
 891                 break;
 892         }
 893
 894         if (state || probe || setup)
 895                 tipc_link_build_proto_msg(l, mtyp, probe, 0, 0, 0, 0, xmitq);
 896
 897         return rc;
 898 }
 899
 900 /**
 901  * link_schedule_user - schedule a message sender for wakeup after congestion
 902  * @l: congested link
 903  * @hdr: header of message that is being sent
 904  * Create pseudo msg to send back to user when congestion abates
 905  */
 906 static int link_schedule_user(struct tipc_link *l, struct tipc_msg *hdr)
 907 {
 908         u32 dnode = tipc_own_addr(l->net);
 909         u32 dport = msg_origport(hdr);
 910         struct sk_buff *skb;
 911
 912         /* Create and schedule wakeup pseudo message */
 913         skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
 914                               dnode, l->addr, dport, 0, 0);
 915         if (!skb)
 916                 return -ENOBUFS;
 917         msg_set_dest_droppable(buf_msg(skb), true);
 918         TIPC_SKB_CB(skb)->chain_imp = msg_importance(hdr);
 919         skb_queue_tail(&l->wakeupq, skb);
 920         l->stats.link_congs++;
 921         trace_tipc_link_conges(l, TIPC_DUMP_ALL, "wakeup scheduled!");
 922         return -ELINKCONG;
 923 }
 924
 925 /**
 926  * link_prepare_wakeup - prepare users for wakeup after congestion
 927  * @l: congested link
 928  * Wake up a number of waiting users, as permitted by available space
 929  * in the send queue
 930  */
 931 static void link_prepare_wakeup(struct tipc_link *l)
 932 {
 933         struct sk_buff_head *wakeupq = &l->wakeupq;
 934         struct sk_buff_head *inputq = l->inputq;
 935         struct sk_buff *skb, *tmp;
 936         struct sk_buff_head tmpq;
 937         int avail[5] = {0,};
 938         int imp = 0;
 939
 940         __skb_queue_head_init(&tmpq);
 941
 942         for (; imp <= TIPC_SYSTEM_IMPORTANCE; imp++)
 943                 avail[imp] = l->backlog[imp].limit - l->backlog[imp].len;
 944
 945         skb_queue_walk_safe(wakeupq, skb, tmp) {
 946                 imp = TIPC_SKB_CB(skb)->chain_imp;
 947                 if (avail[imp] <= 0)
 948                         continue;
 949                 avail[imp]--;
 950                 __skb_unlink(skb, wakeupq);
 951                 __skb_queue_tail(&tmpq, skb);
 952         }
 953
 954         spin_lock_bh(&inputq->lock);
 955         skb_queue_splice_tail(&tmpq, inputq);
 956         spin_unlock_bh(&inputq->lock);
 957
 958 }
 959
 960 /**
 961  * tipc_link_set_skb_retransmit_time - set the time at which retransmission of
 962  *                                     the given skb should be next attempted
 963  * @skb: skb to set a future retransmission time for
 964  * @l: link the skb will be transmitted on
 965  */
 966 static void tipc_link_set_skb_retransmit_time(struct sk_buff *skb,
 967                                               struct tipc_link *l)
 968 {
 969         if (link_is_bc_sndlink(l))
 970                 TIPC_SKB_CB(skb)->nxt_retr = TIPC_BC_RETR_LIM;
 971         else
 972                 TIPC_SKB_CB(skb)->nxt_retr = TIPC_UC_RETR_TIME;
 973 }
 974
 975 void tipc_link_reset(struct tipc_link *l)
 976 {
 977         struct sk_buff_head list;
 978         u32 imp;
 979
 980         __skb_queue_head_init(&list);
 981
 982         l->in_session = false;
 983         /* Force re-synch of peer session number before establishing */
 984         l->peer_session--;
 985         l->session++;
 986         l->mtu = l->advertised_mtu;
 987
 988         spin_lock_bh(&l->wakeupq.lock);
 989         skb_queue_splice_init(&l->wakeupq, &list);
 990         spin_unlock_bh(&l->wakeupq.lock);
 991
 992         spin_lock_bh(&l->inputq->lock);
 993         skb_queue_splice_init(&list, l->inputq);
 994         spin_unlock_bh(&l->inputq->lock);
 995
 996         __skb_queue_purge(&l->transmq);
 997         __skb_queue_purge(&l->deferdq);
 998         __skb_queue_purge(&l->backlogq);
 999         __skb_queue_purge(&l->failover_deferdq);
1000         for (imp = 0; imp <= TIPC_SYSTEM_IMPORTANCE; imp++) {
1001                 l->backlog[imp].len = 0;
1002                 l->backlog[imp].target_bskb = NULL;
1003         }
1004         kfree_skb(l->reasm_buf);
1005         kfree_skb(l->reasm_tnlmsg);
1006         kfree_skb(l->failover_reasm_skb);
1007         l->reasm_buf = NULL;
1008         l->reasm_tnlmsg = NULL;
1009         l->failover_reasm_skb = NULL;
1010         l->rcv_unacked = 0;
1011         l->snd_nxt = 1;
1012         l->rcv_nxt = 1;
1013         l->snd_nxt_state = 1;
1014         l->rcv_nxt_state = 1;
1015         l->acked = 0;
1016         l->last_gap = 0;
1017         kfree(l->last_ga);
1018         l->last_ga = NULL;
1019         l->silent_intv_cnt = 0;
1020         l->rst_cnt = 0;
1021         l->bc_peer_is_up = false;
1022         memset(&l->mon_state, 0, sizeof(l->mon_state));
1023         tipc_link_reset_stats(l);
1024 }
1025
1026 /**
1027  * tipc_link_xmit(): enqueue buffer list according to queue situation
1028  * @l: link to use
1029  * @list: chain of buffers containing message
1030  * @xmitq: returned list of packets to be sent by caller
1031  *
1032  * Consumes the buffer chain.
1033  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
1034  * Return: 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
1035  */
1036 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
1037                    struct sk_buff_head *xmitq)
1038 {
1039         struct sk_buff_head *backlogq = &l->backlogq;
1040         struct sk_buff_head *transmq = &l->transmq;
1041         struct sk_buff *skb, *_skb;
1042         u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1043         u16 ack = l->rcv_nxt - 1;
1044         u16 seqno = l->snd_nxt;
1045         int pkt_cnt = skb_queue_len(list);
1046         unsigned int mss = tipc_link_mss(l);
1047         unsigned int cwin = l->window;
1048         unsigned int mtu = l->mtu;
1049         struct tipc_msg *hdr;
1050         bool new_bundle;
1051         int rc = 0;
1052         int imp;
1053
1054         if (pkt_cnt <= 0)
1055                 return 0;
1056
1057         hdr = buf_msg(skb_peek(list));
1058         if (unlikely(msg_size(hdr) > mtu)) {
1059                 pr_warn("Too large msg, purging xmit list %d %d %d %d %d!\n",
1060                         skb_queue_len(list), msg_user(hdr),
1061                         msg_type(hdr), msg_size(hdr), mtu);
1062                 __skb_queue_purge(list);
1063                 return -EMSGSIZE;
1064         }
1065
1066         imp = msg_importance(hdr);
1067         /* Allow oversubscription of one data msg per source at congestion */
1068         if (unlikely(l->backlog[imp].len >= l->backlog[imp].limit)) {
1069                 if (imp == TIPC_SYSTEM_IMPORTANCE) {
1070                         pr_warn("%s<%s>, link overflow", link_rst_msg, l->name);
1071                         return -ENOBUFS;
1072                 }
1073                 rc = link_schedule_user(l, hdr);
1074         }
1075
1076         if (pkt_cnt > 1) {
1077                 l->stats.sent_fragmented++;
1078                 l->stats.sent_fragments += pkt_cnt;
1079         }
1080
1081         /* Prepare each packet for sending, and add to relevant queue: */
1082         while ((skb = __skb_dequeue(list))) {
1083                 if (likely(skb_queue_len(transmq) < cwin)) {
1084                         hdr = buf_msg(skb);
1085                         msg_set_seqno(hdr, seqno);
1086                         msg_set_ack(hdr, ack);
1087                         msg_set_bcast_ack(hdr, bc_ack);
1088                         _skb = skb_clone(skb, GFP_ATOMIC);
1089                         if (!_skb) {
1090                                 kfree_skb(skb);
1091                                 __skb_queue_purge(list);
1092                                 return -ENOBUFS;
1093                         }
1094                         __skb_queue_tail(transmq, skb);
1095                         tipc_link_set_skb_retransmit_time(skb, l);
1096                         __skb_queue_tail(xmitq, _skb);
1097                         TIPC_SKB_CB(skb)->ackers = l->ackers;
1098                         l->rcv_unacked = 0;
1099                         l->stats.sent_pkts++;
1100                         seqno++;
1101                         continue;
1102                 }
1103                 if (tipc_msg_try_bundle(l->backlog[imp].target_bskb, &skb,
1104                                         mss, l->addr, &new_bundle)) {
1105                         if (skb) {
1106                                 /* Keep a ref. to the skb for next try */
1107                                 l->backlog[imp].target_bskb = skb;
1108                                 l->backlog[imp].len++;
1109                                 __skb_queue_tail(backlogq, skb);
1110                         } else {
1111                                 if (new_bundle) {
1112                                         l->stats.sent_bundles++;
1113                                         l->stats.sent_bundled++;
1114                                 }
1115                                 l->stats.sent_bundled++;
1116                         }
1117                         continue;
1118                 }
1119                 l->backlog[imp].target_bskb = NULL;
1120                 l->backlog[imp].len += (1 + skb_queue_len(list));
1121                 __skb_queue_tail(backlogq, skb);
1122                 skb_queue_splice_tail_init(list, backlogq);
1123         }
1124         l->snd_nxt = seqno;
1125         return rc;
1126 }
1127
1128 static void tipc_link_update_cwin(struct tipc_link *l, int released,
1129                                   bool retransmitted)
1130 {
1131         int bklog_len = skb_queue_len(&l->backlogq);
1132         struct sk_buff_head *txq = &l->transmq;
1133         int txq_len = skb_queue_len(txq);
1134         u16 cwin = l->window;
1135
1136         /* Enter fast recovery */
1137         if (unlikely(retransmitted)) {
1138                 l->ssthresh = max_t(u16, l->window / 2, 300);
1139                 l->window = min_t(u16, l->ssthresh, l->window);
1140                 return;
1141         }
1142         /* Enter slow start */
1143         if (unlikely(!released)) {
1144                 l->ssthresh = max_t(u16, l->window / 2, 300);
1145                 l->window = l->min_win;
1146                 return;
1147         }
1148         /* Don't increase window if no pressure on the transmit queue */
1149         if (txq_len + bklog_len < cwin)
1150                 return;
1151
1152         /* Don't increase window if there are holes the transmit queue */
1153         if (txq_len && l->snd_nxt - buf_seqno(skb_peek(txq)) != txq_len)
1154                 return;
1155
1156         l->cong_acks += released;
1157
1158         /* Slow start  */
1159         if (cwin <= l->ssthresh) {
1160                 l->window = min_t(u16, cwin + released, l->max_win);
1161                 return;
1162         }
1163         /* Congestion avoidance */
1164         if (l->cong_acks < cwin)
1165                 return;
1166         l->window = min_t(u16, ++cwin, l->max_win);
1167         l->cong_acks = 0;
1168 }
1169
1170 static void tipc_link_advance_backlog(struct tipc_link *l,
1171                                       struct sk_buff_head *xmitq)
1172 {
1173         u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1174         struct sk_buff_head *txq = &l->transmq;
1175         struct sk_buff *skb, *_skb;
1176         u16 ack = l->rcv_nxt - 1;
1177         u16 seqno = l->snd_nxt;
1178         struct tipc_msg *hdr;
1179         u16 cwin = l->window;
1180         u32 imp;
1181
1182         while (skb_queue_len(txq) < cwin) {
1183                 skb = skb_peek(&l->backlogq);
1184                 if (!skb)
1185                         break;
1186                 _skb = skb_clone(skb, GFP_ATOMIC);
1187                 if (!_skb)
1188                         break;
1189                 __skb_dequeue(&l->backlogq);
1190                 hdr = buf_msg(skb);
1191                 imp = msg_importance(hdr);
1192                 l->backlog[imp].len--;
1193                 if (unlikely(skb == l->backlog[imp].target_bskb))
1194                         l->backlog[imp].target_bskb = NULL;
1195                 __skb_queue_tail(&l->transmq, skb);
1196                 tipc_link_set_skb_retransmit_time(skb, l);
1197
1198                 __skb_queue_tail(xmitq, _skb);
1199                 TIPC_SKB_CB(skb)->ackers = l->ackers;
1200                 msg_set_seqno(hdr, seqno);
1201                 msg_set_ack(hdr, ack);
1202                 msg_set_bcast_ack(hdr, bc_ack);
1203                 l->rcv_unacked = 0;
1204                 l->stats.sent_pkts++;
1205                 seqno++;
1206         }
1207         l->snd_nxt = seqno;
1208 }
1209
1210 /**
1211  * link_retransmit_failure() - Detect repeated retransmit failures
1212  * @l: tipc link sender
1213  * @r: tipc link receiver (= l in case of unicast)
1214  * @rc: returned code
1215  *
1216  * Return: true if the repeated retransmit failures happens, otherwise
1217  * false
1218  */
1219 static bool link_retransmit_failure(struct tipc_link *l, struct tipc_link *r,
1220                                     int *rc)
1221 {
1222         struct sk_buff *skb = skb_peek(&l->transmq);
1223         struct tipc_msg *hdr;
1224
1225         if (!skb)
1226                 return false;
1227
1228         if (!TIPC_SKB_CB(skb)->retr_cnt)
1229                 return false;
1230
1231         if (!time_after(jiffies, TIPC_SKB_CB(skb)->retr_stamp +
1232                         msecs_to_jiffies(r->tolerance * 10)))
1233                 return false;
1234
1235         hdr = buf_msg(skb);
1236         if (link_is_bc_sndlink(l) && !less(r->acked, msg_seqno(hdr)))
1237                 return false;
1238
1239         pr_warn("Retransmission failure on link <%s>\n", l->name);
1240         link_print(l, "State of link ");
1241         pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
1242                 msg_user(hdr), msg_type(hdr), msg_size(hdr), msg_errcode(hdr));
1243         pr_info("sqno %u, prev: %x, dest: %x\n",
1244                 msg_seqno(hdr), msg_prevnode(hdr), msg_destnode(hdr));
1245         pr_info("retr_stamp %d, retr_cnt %d\n",
1246                 jiffies_to_msecs(TIPC_SKB_CB(skb)->retr_stamp),
1247                 TIPC_SKB_CB(skb)->retr_cnt);
1248
1249         trace_tipc_list_dump(&l->transmq, true, "retrans failure!");
1250         trace_tipc_link_dump(l, TIPC_DUMP_NONE, "retrans failure!");
1251         trace_tipc_link_dump(r, TIPC_DUMP_NONE, "retrans failure!");
1252
1253         if (link_is_bc_sndlink(l)) {
1254                 r->state = LINK_RESET;
1255                 *rc |= TIPC_LINK_DOWN_EVT;
1256         } else {
1257                 *rc |= tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1258         }
1259
1260         return true;
1261 }
1262
1263 /* tipc_data_input - deliver data and name distr msgs to upper layer
1264  *
1265  * Consumes buffer if message is of right type
1266  * Node lock must be held
1267  */
1268 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
1269                             struct sk_buff_head *inputq)
1270 {
1271         struct sk_buff_head *mc_inputq = l->bc_rcvlink->inputq;
1272         struct tipc_msg *hdr = buf_msg(skb);
1273
1274         switch (msg_user(hdr)) {
1275         case TIPC_LOW_IMPORTANCE:
1276         case TIPC_MEDIUM_IMPORTANCE:
1277         case TIPC_HIGH_IMPORTANCE:
1278         case TIPC_CRITICAL_IMPORTANCE:
1279                 if (unlikely(msg_in_group(hdr) || msg_mcast(hdr))) {
1280                         skb_queue_tail(mc_inputq, skb);
1281                         return true;
1282                 }
1283                 fallthrough;
1284         case CONN_MANAGER:
1285                 skb_queue_tail(inputq, skb);
1286                 return true;
1287         case GROUP_PROTOCOL:
1288                 skb_queue_tail(mc_inputq, skb);
1289                 return true;
1290         case NAME_DISTRIBUTOR:
1291                 l->bc_rcvlink->state = LINK_ESTABLISHED;
1292                 skb_queue_tail(l->namedq, skb);
1293                 return true;
1294         case MSG_BUNDLER:
1295         case TUNNEL_PROTOCOL:
1296         case MSG_FRAGMENTER:
1297         case BCAST_PROTOCOL:
1298                 return false;
1299 #ifdef CONFIG_TIPC_CRYPTO
1300         case MSG_CRYPTO:
1301                 if (sysctl_tipc_key_exchange_enabled &&
1302                     TIPC_SKB_CB(skb)->decrypted) {
1303                         tipc_crypto_msg_rcv(l->net, skb);
1304                         return true;
1305                 }
1306                 fallthrough;
1307 #endif
1308         default:
1309                 pr_warn("Dropping received illegal msg type\n");
1310                 kfree_skb(skb);
1311                 return true;
1312         }
1313 }
1314
1315 /* tipc_link_input - process packet that has passed link protocol check
1316  *
1317  * Consumes buffer
1318  */
1319 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
1320                            struct sk_buff_head *inputq,
1321                            struct sk_buff **reasm_skb)
1322 {
1323         struct tipc_msg *hdr = buf_msg(skb);
1324         struct sk_buff *iskb;
1325         struct sk_buff_head tmpq;
1326         int usr = msg_user(hdr);
1327         int pos = 0;
1328
1329         if (usr == MSG_BUNDLER) {
1330                 skb_queue_head_init(&tmpq);
1331                 l->stats.recv_bundles++;
1332                 l->stats.recv_bundled += msg_msgcnt(hdr);
1333                 while (tipc_msg_extract(skb, &iskb, &pos))
1334                         tipc_data_input(l, iskb, &tmpq);
1335                 tipc_skb_queue_splice_tail(&tmpq, inputq);
1336                 return 0;
1337         } else if (usr == MSG_FRAGMENTER) {
1338                 l->stats.recv_fragments++;
1339                 if (tipc_buf_append(reasm_skb, &skb)) {
1340                         l->stats.recv_fragmented++;
1341                         tipc_data_input(l, skb, inputq);
1342                 } else if (!*reasm_skb && !link_is_bc_rcvlink(l)) {
1343                         pr_warn_ratelimited("Unable to build fragment list\n");
1344                         return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1345                 }
1346                 return 0;
1347         } else if (usr == BCAST_PROTOCOL) {
1348                 tipc_bcast_lock(l->net);
1349                 tipc_link_bc_init_rcv(l->bc_rcvlink, hdr);
1350                 tipc_bcast_unlock(l->net);
1351         }
1352
1353         kfree_skb(skb);
1354         return 0;
1355 }
1356
1357 /* tipc_link_tnl_rcv() - receive TUNNEL_PROTOCOL message, drop or process the
1358  *                       inner message along with the ones in the old link's
1359  *                       deferdq
1360  * @l: tunnel link
1361  * @skb: TUNNEL_PROTOCOL message
1362  * @inputq: queue to put messages ready for delivery
1363  */
1364 static int tipc_link_tnl_rcv(struct tipc_link *l, struct sk_buff *skb,
1365                              struct sk_buff_head *inputq)
1366 {
1367         struct sk_buff **reasm_skb = &l->failover_reasm_skb;
1368         struct sk_buff **reasm_tnlmsg = &l->reasm_tnlmsg;
1369         struct sk_buff_head *fdefq = &l->failover_deferdq;
1370         struct tipc_msg *hdr = buf_msg(skb);
1371         struct sk_buff *iskb;
1372         int ipos = 0;
1373         int rc = 0;
1374         u16 seqno;
1375
1376         if (msg_type(hdr) == SYNCH_MSG) {
1377                 kfree_skb(skb);
1378                 return 0;
1379         }
1380
1381         /* Not a fragment? */
1382         if (likely(!msg_nof_fragms(hdr))) {
1383                 if (unlikely(!tipc_msg_extract(skb, &iskb, &ipos))) {
1384                         pr_warn_ratelimited("Unable to extract msg, defq: %d\n",
1385                                             skb_queue_len(fdefq));
1386                         return 0;
1387                 }
1388                 kfree_skb(skb);
1389         } else {
1390                 /* Set fragment type for buf_append */
1391                 if (msg_fragm_no(hdr) == 1)
1392                         msg_set_type(hdr, FIRST_FRAGMENT);
1393                 else if (msg_fragm_no(hdr) < msg_nof_fragms(hdr))
1394                         msg_set_type(hdr, FRAGMENT);
1395                 else
1396                         msg_set_type(hdr, LAST_FRAGMENT);
1397
1398                 if (!tipc_buf_append(reasm_tnlmsg, &skb)) {
1399                         /* Successful but non-complete reassembly? */
1400                         if (*reasm_tnlmsg || link_is_bc_rcvlink(l))
1401                                 return 0;
1402                         pr_warn_ratelimited("Unable to reassemble tunnel msg\n");
1403                         return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1404                 }
1405                 iskb = skb;
1406         }
1407
1408         do {
1409                 seqno = buf_seqno(iskb);
1410                 if (unlikely(less(seqno, l->drop_point))) {
1411                         kfree_skb(iskb);
1412                         continue;
1413                 }
1414                 if (unlikely(seqno != l->drop_point)) {
1415                         __tipc_skb_queue_sorted(fdefq, seqno, iskb);
1416                         continue;
1417                 }
1418
1419                 l->drop_point++;
1420                 if (!tipc_data_input(l, iskb, inputq))
1421                         rc |= tipc_link_input(l, iskb, inputq, reasm_skb);
1422                 if (unlikely(rc))
1423                         break;
1424         } while ((iskb = __tipc_skb_dequeue(fdefq, l->drop_point)));
1425
1426         return rc;
1427 }
1428
1429 /**
1430  * tipc_get_gap_ack_blks - get Gap ACK blocks from PROTOCOL/STATE_MSG
1431  * @ga: returned pointer to the Gap ACK blocks if any
1432  * @l: the tipc link
1433  * @hdr: the PROTOCOL/STATE_MSG header
1434  * @uc: desired Gap ACK blocks type, i.e. unicast (= 1) or broadcast (= 0)
1435  *
1436  * Return: the total Gap ACK blocks size
1437  */
1438 u16 tipc_get_gap_ack_blks(struct tipc_gap_ack_blks **ga, struct tipc_link *l,
1439                           struct tipc_msg *hdr, bool uc)
1440 {
1441         struct tipc_gap_ack_blks *p;
1442         u16 sz = 0;
1443
1444         /* Does peer support the Gap ACK blocks feature? */
1445         if (l->peer_caps & TIPC_GAP_ACK_BLOCK) {
1446                 p = (struct tipc_gap_ack_blks *)msg_data(hdr);
1447                 sz = ntohs(p->len);
1448                 /* Sanity check */
1449                 if (sz == struct_size(p, gacks, size_add(p->ugack_cnt, p->bgack_cnt))) {
1450                         /* Good, check if the desired type exists */
1451                         if ((uc && p->ugack_cnt) || (!uc && p->bgack_cnt))
1452                                 goto ok;
1453                 /* Backward compatible: peer might not support bc, but uc? */
1454                 } else if (uc && sz == struct_size(p, gacks, p->ugack_cnt)) {
1455                         if (p->ugack_cnt) {
1456                                 p->bgack_cnt = 0;
1457                                 goto ok;
1458                         }
1459                 }
1460         }
1461         /* Other cases: ignore! */
1462         p = NULL;
1463
1464 ok:
1465         *ga = p;
1466         return sz;
1467 }
1468
1469 static u8 __tipc_build_gap_ack_blks(struct tipc_gap_ack_blks *ga,
1470                                     struct tipc_link *l, u8 start_index)
1471 {
1472         struct tipc_gap_ack *gacks = &ga->gacks[start_index];
1473         struct sk_buff *skb = skb_peek(&l->deferdq);
1474         u16 expect, seqno = 0;
1475         u8 n = 0;
1476
1477         if (!skb)
1478                 return 0;
1479
1480         expect = buf_seqno(skb);
1481         skb_queue_walk(&l->deferdq, skb) {
1482                 seqno = buf_seqno(skb);
1483                 if (unlikely(more(seqno, expect))) {
1484                         gacks[n].ack = htons(expect - 1);
1485                         gacks[n].gap = htons(seqno - expect);
1486                         if (++n >= MAX_GAP_ACK_BLKS / 2) {
1487                                 pr_info_ratelimited("Gacks on %s: %d, ql: %d!\n",
1488                                                     l->name, n,
1489                                                     skb_queue_len(&l->deferdq));
1490                                 return n;
1491                         }
1492                 } else if (unlikely(less(seqno, expect))) {
1493                         pr_warn("Unexpected skb in deferdq!\n");
1494                         continue;
1495                 }
1496                 expect = seqno + 1;
1497         }
1498
1499         /* last block */
1500         gacks[n].ack = htons(seqno);
1501         gacks[n].gap = 0;
1502         n++;
1503         return n;
1504 }
1505
1506 /* tipc_build_gap_ack_blks - build Gap ACK blocks
1507  * @l: tipc unicast link
1508  * @hdr: the tipc message buffer to store the Gap ACK blocks after built
1509  *
1510  * The function builds Gap ACK blocks for both the unicast & broadcast receiver
1511  * links of a certain peer, the buffer after built has the network data format
1512  * as found at the struct tipc_gap_ack_blks definition.
1513  *
1514  * returns the actual allocated memory size
1515  */
1516 static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr)
1517 {
1518         struct tipc_link *bcl = l->bc_rcvlink;
1519         struct tipc_gap_ack_blks *ga;
1520         u16 len;
1521
1522         ga = (struct tipc_gap_ack_blks *)msg_data(hdr);
1523
1524         /* Start with broadcast link first */
1525         tipc_bcast_lock(bcl->net);
1526         msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1527         msg_set_bc_gap(hdr, link_bc_rcv_gap(bcl));
1528         ga->bgack_cnt = __tipc_build_gap_ack_blks(ga, bcl, 0);
1529         tipc_bcast_unlock(bcl->net);
1530
1531         /* Now for unicast link, but an explicit NACK only (???) */
1532         ga->ugack_cnt = (msg_seq_gap(hdr)) ?
1533                         __tipc_build_gap_ack_blks(ga, l, ga->bgack_cnt) : 0;
1534
1535         /* Total len */
1536         len = struct_size(ga, gacks, size_add(ga->bgack_cnt, ga->ugack_cnt));
1537         ga->len = htons(len);
1538         return len;
1539 }
1540
1541 /* tipc_link_advance_transmq - advance TIPC link transmq queue by releasing
1542  *                             acked packets, also doing retransmissions if
1543  *                             gaps found
1544  * @l: tipc link with transmq queue to be advanced
1545  * @r: tipc link "receiver" i.e. in case of broadcast (= "l" if unicast)
1546  * @acked: seqno of last packet acked by peer without any gaps before
1547  * @gap: # of gap packets
1548  * @ga: buffer pointer to Gap ACK blocks from peer
1549  * @xmitq: queue for accumulating the retransmitted packets if any
1550  * @retransmitted: returned boolean value if a retransmission is really issued
1551  * @rc: returned code e.g. TIPC_LINK_DOWN_EVT if a repeated retransmit failures
1552  *      happens (- unlikely case)
1553  *
1554  * Return: the number of packets released from the link transmq
1555  */
1556 static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
1557                                      u16 acked, u16 gap,
1558                                      struct tipc_gap_ack_blks *ga,
1559                                      struct sk_buff_head *xmitq,
1560                                      bool *retransmitted, int *rc)
1561 {
1562         struct tipc_gap_ack_blks *last_ga = r->last_ga, *this_ga = NULL;
1563         struct tipc_gap_ack *gacks = NULL;
1564         struct sk_buff *skb, *_skb, *tmp;
1565         struct tipc_msg *hdr;
1566         u32 qlen = skb_queue_len(&l->transmq);
1567         u16 nacked = acked, ngap = gap, gack_cnt = 0;
1568         u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1569         u16 ack = l->rcv_nxt - 1;
1570         u16 seqno, n = 0;
1571         u16 end = r->acked, start = end, offset = r->last_gap;
1572         u16 si = (last_ga) ? last_ga->start_index : 0;
1573         bool is_uc = !link_is_bc_sndlink(l);
1574         bool bc_has_acked = false;
1575
1576         trace_tipc_link_retrans(r, acked + 1, acked + gap, &l->transmq);
1577
1578         /* Determine Gap ACK blocks if any for the particular link */
1579         if (ga && is_uc) {
1580                 /* Get the Gap ACKs, uc part */
1581                 gack_cnt = ga->ugack_cnt;
1582                 gacks = &ga->gacks[ga->bgack_cnt];
1583         } else if (ga) {
1584                 /* Copy the Gap ACKs, bc part, for later renewal if needed */
1585                 this_ga = kmemdup(ga, struct_size(ga, gacks, ga->bgack_cnt),
1586                                   GFP_ATOMIC);
1587                 if (likely(this_ga)) {
1588                         this_ga->start_index = 0;
1589                         /* Start with the bc Gap ACKs */
1590                         gack_cnt = this_ga->bgack_cnt;
1591                         gacks = &this_ga->gacks[0];
1592                 } else {
1593                         /* Hmm, we can get in trouble..., simply ignore it */
1594                         pr_warn_ratelimited("Ignoring bc Gap ACKs, no memory\n");
1595                 }
1596         }
1597
1598         /* Advance the link transmq */
1599         skb_queue_walk_safe(&l->transmq, skb, tmp) {
1600                 seqno = buf_seqno(skb);
1601
1602 next_gap_ack:
1603                 if (less_eq(seqno, nacked)) {
1604                         if (is_uc)
1605                                 goto release;
1606                         /* Skip packets peer has already acked */
1607                         if (!more(seqno, r->acked))
1608                                 continue;
1609                         /* Get the next of last Gap ACK blocks */
1610                         while (more(seqno, end)) {
1611                                 if (!last_ga || si >= last_ga->bgack_cnt)
1612                                         break;
1613                                 start = end + offset + 1;
1614                                 end = ntohs(last_ga->gacks[si].ack);
1615                                 offset = ntohs(last_ga->gacks[si].gap);
1616                                 si++;
1617                                 WARN_ONCE(more(start, end) ||
1618                                           (!offset &&
1619                                            si < last_ga->bgack_cnt) ||
1620                                           si > MAX_GAP_ACK_BLKS,
1621                                           "Corrupted Gap ACK: %d %d %d %d %d\n",
1622                                           start, end, offset, si,
1623                                           last_ga->bgack_cnt);
1624                         }
1625                         /* Check against the last Gap ACK block */
1626                         if (tipc_in_range(seqno, start, end))
1627                                 continue;
1628                         /* Update/release the packet peer is acking */
1629                         bc_has_acked = true;
1630                         if (--TIPC_SKB_CB(skb)->ackers)
1631                                 continue;
1632 release:
1633                         /* release skb */
1634                         __skb_unlink(skb, &l->transmq);
1635                         kfree_skb(skb);
1636                 } else if (less_eq(seqno, nacked + ngap)) {
1637                         /* First gap: check if repeated retrans failures? */
1638                         if (unlikely(seqno == acked + 1 &&
1639                                      link_retransmit_failure(l, r, rc))) {
1640                                 /* Ignore this bc Gap ACKs if any */
1641                                 kfree(this_ga);
1642                                 this_ga = NULL;
1643                                 break;
1644                         }
1645                         /* retransmit skb if unrestricted*/
1646                         if (time_before(jiffies, TIPC_SKB_CB(skb)->nxt_retr))
1647                                 continue;
1648                         tipc_link_set_skb_retransmit_time(skb, l);
1649                         _skb = pskb_copy(skb, GFP_ATOMIC);
1650                         if (!_skb)
1651                                 continue;
1652                         hdr = buf_msg(_skb);
1653                         msg_set_ack(hdr, ack);
1654                         msg_set_bcast_ack(hdr, bc_ack);
1655                         _skb->priority = TC_PRIO_CONTROL;
1656                         __skb_queue_tail(xmitq, _skb);
1657                         l->stats.retransmitted++;
1658                         if (!is_uc)
1659                                 r->stats.retransmitted++;
1660                         *retransmitted = true;
1661                         /* Increase actual retrans counter & mark first time */
1662                         if (!TIPC_SKB_CB(skb)->retr_cnt++)
1663                                 TIPC_SKB_CB(skb)->retr_stamp = jiffies;
1664                 } else {
1665                         /* retry with Gap ACK blocks if any */
1666                         if (n >= gack_cnt)
1667                                 break;
1668                         nacked = ntohs(gacks[n].ack);
1669                         ngap = ntohs(gacks[n].gap);
1670                         n++;
1671                         goto next_gap_ack;
1672                 }
1673         }
1674
1675         /* Renew last Gap ACK blocks for bc if needed */
1676         if (bc_has_acked) {
1677                 if (this_ga) {
1678                         kfree(last_ga);
1679                         r->last_ga = this_ga;
1680                         r->last_gap = gap;
1681                 } else if (last_ga) {
1682                         if (less(acked, start)) {
1683                                 si--;
1684                                 offset = start - acked - 1;
1685                         } else if (less(acked, end)) {
1686                                 acked = end;
1687                         }
1688                         if (si < last_ga->bgack_cnt) {
1689                                 last_ga->start_index = si;
1690                                 r->last_gap = offset;
1691                         } else {
1692                                 kfree(last_ga);
1693                                 r->last_ga = NULL;
1694                                 r->last_gap = 0;
1695                         }
1696                 } else {
1697                         r->last_gap = 0;
1698                 }
1699                 r->acked = acked;
1700         } else {
1701                 kfree(this_ga);
1702         }
1703
1704         return qlen - skb_queue_len(&l->transmq);
1705 }
1706
1707 /* tipc_link_build_state_msg: prepare link state message for transmission
1708  *
1709  * Note that sending of broadcast ack is coordinated among nodes, to reduce
1710  * risk of ack storms towards the sender
1711  */
1712 int tipc_link_build_state_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1713 {
1714         if (!l)
1715                 return 0;
1716
1717         /* Broadcast ACK must be sent via a unicast link => defer to caller */
1718         if (link_is_bc_rcvlink(l)) {
1719                 if (((l->rcv_nxt ^ tipc_own_addr(l->net)) & 0xf) != 0xf)
1720                         return 0;
1721                 l->rcv_unacked = 0;
1722
1723                 /* Use snd_nxt to store peer's snd_nxt in broadcast rcv link */
1724                 l->snd_nxt = l->rcv_nxt;
1725                 return TIPC_LINK_SND_STATE;
1726         }
1727         /* Unicast ACK */
1728         l->rcv_unacked = 0;
1729         l->stats.sent_acks++;
1730         tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, 0, xmitq);
1731         return 0;
1732 }
1733
1734 /* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
1735  */
1736 void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1737 {
1738         int mtyp = RESET_MSG;
1739         struct sk_buff *skb;
1740
1741         if (l->state == LINK_ESTABLISHING)
1742                 mtyp = ACTIVATE_MSG;
1743
1744         tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, 0, xmitq);
1745
1746         /* Inform peer that this endpoint is going down if applicable */
1747         skb = skb_peek_tail(xmitq);
1748         if (skb && (l->state == LINK_RESET))
1749                 msg_set_peer_stopping(buf_msg(skb), 1);
1750 }
1751
1752 /* tipc_link_build_nack_msg: prepare link nack message for transmission
1753  * Note that sending of broadcast NACK is coordinated among nodes, to
1754  * reduce the risk of NACK storms towards the sender
1755  */
1756 static int tipc_link_build_nack_msg(struct tipc_link *l,
1757                                     struct sk_buff_head *xmitq)
1758 {
1759         u32 def_cnt = ++l->stats.deferred_recv;
1760         struct sk_buff_head *dfq = &l->deferdq;
1761         u32 defq_len = skb_queue_len(dfq);
1762         int match1, match2;
1763
1764         if (link_is_bc_rcvlink(l)) {
1765                 match1 = def_cnt & 0xf;
1766                 match2 = tipc_own_addr(l->net) & 0xf;
1767                 if (match1 == match2)
1768                         return TIPC_LINK_SND_STATE;
1769                 return 0;
1770         }
1771
1772         if (defq_len >= 3 && !((defq_len - 3) % 16)) {
1773                 u16 rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1774
1775                 tipc_link_build_proto_msg(l, STATE_MSG, 0, 0,
1776                                           rcvgap, 0, 0, xmitq);
1777         }
1778         return 0;
1779 }
1780
1781 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1782  * @l: the link that should handle the message
1783  * @skb: TIPC packet
1784  * @xmitq: queue to place packets to be sent after this call
1785  */
1786 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1787                   struct sk_buff_head *xmitq)
1788 {
1789         struct sk_buff_head *defq = &l->deferdq;
1790         struct tipc_msg *hdr = buf_msg(skb);
1791         u16 seqno, rcv_nxt, win_lim;
1792         int released = 0;
1793         int rc = 0;
1794
1795         /* Verify and update link state */
1796         if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
1797                 return tipc_link_proto_rcv(l, skb, xmitq);
1798
1799         /* Don't send probe at next timeout expiration */
1800         l->silent_intv_cnt = 0;
1801
1802         do {
1803                 hdr = buf_msg(skb);
1804                 seqno = msg_seqno(hdr);
1805                 rcv_nxt = l->rcv_nxt;
1806                 win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;
1807
1808                 if (unlikely(!link_is_up(l))) {
1809                         if (l->state == LINK_ESTABLISHING)
1810                                 rc = TIPC_LINK_UP_EVT;
1811                         kfree_skb(skb);
1812                         break;
1813                 }
1814
1815                 /* Drop if outside receive window */
1816                 if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
1817                         l->stats.duplicates++;
1818                         kfree_skb(skb);
1819                         break;
1820                 }
1821                 released += tipc_link_advance_transmq(l, l, msg_ack(hdr), 0,
1822                                                       NULL, NULL, NULL, NULL);
1823
1824                 /* Defer delivery if sequence gap */
1825                 if (unlikely(seqno != rcv_nxt)) {
1826                         if (!__tipc_skb_queue_sorted(defq, seqno, skb))
1827                                 l->stats.duplicates++;
1828                         rc |= tipc_link_build_nack_msg(l, xmitq);
1829                         break;
1830                 }
1831
1832                 /* Deliver packet */
1833                 l->rcv_nxt++;
1834                 l->stats.recv_pkts++;
1835
1836                 if (unlikely(msg_user(hdr) == TUNNEL_PROTOCOL))
1837                         rc |= tipc_link_tnl_rcv(l, skb, l->inputq);
1838                 else if (!tipc_data_input(l, skb, l->inputq))
1839                         rc |= tipc_link_input(l, skb, l->inputq, &l->reasm_buf);
1840                 if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
1841                         rc |= tipc_link_build_state_msg(l, xmitq);
1842                 if (unlikely(rc & ~TIPC_LINK_SND_STATE))
1843                         break;
1844         } while ((skb = __tipc_skb_dequeue(defq, l->rcv_nxt)));
1845
1846         /* Forward queues and wake up waiting users */
1847         if (released) {
1848                 tipc_link_update_cwin(l, released, 0);
1849                 tipc_link_advance_backlog(l, xmitq);
1850                 if (unlikely(!skb_queue_empty(&l->wakeupq)))
1851                         link_prepare_wakeup(l);
1852         }
1853         return rc;
1854 }
1855
1856 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1857                                       bool probe_reply, u16 rcvgap,
1858                                       int tolerance, int priority,
1859                                       struct sk_buff_head *xmitq)
1860 {
1861         struct tipc_mon_state *mstate = &l->mon_state;
1862         struct sk_buff_head *dfq = &l->deferdq;
1863         struct tipc_link *bcl = l->bc_rcvlink;
1864         struct tipc_msg *hdr;
1865         struct sk_buff *skb;
1866         bool node_up = link_is_up(bcl);
1867         u16 glen = 0, bc_rcvgap = 0;
1868         int dlen = 0;
1869         void *data;
1870
1871         /* Don't send protocol message during reset or link failover */
1872         if (tipc_link_is_blocked(l))
1873                 return;
1874
1875         if (!tipc_link_is_up(l) && (mtyp == STATE_MSG))
1876                 return;
1877
1878         if ((probe || probe_reply) && !skb_queue_empty(dfq))
1879                 rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1880
1881         skb = tipc_msg_create(LINK_PROTOCOL, mtyp, INT_H_SIZE,
1882                               tipc_max_domain_size + MAX_GAP_ACK_BLKS_SZ,
1883                               l->addr, tipc_own_addr(l->net), 0, 0, 0);
1884         if (!skb)
1885                 return;
1886
1887         hdr = buf_msg(skb);
1888         data = msg_data(hdr);
1889         msg_set_session(hdr, l->session);
1890         msg_set_bearer_id(hdr, l->bearer_id);
1891         msg_set_net_plane(hdr, l->net_plane);
1892         msg_set_next_sent(hdr, l->snd_nxt);
1893         msg_set_ack(hdr, l->rcv_nxt - 1);
1894         msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1895         msg_set_bc_ack_invalid(hdr, !node_up);
1896         msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1897         msg_set_link_tolerance(hdr, tolerance);
1898         msg_set_linkprio(hdr, priority);
1899         msg_set_redundant_link(hdr, node_up);
1900         msg_set_seq_gap(hdr, 0);
1901         msg_set_seqno(hdr, l->snd_nxt + U16_MAX / 2);
1902
1903         if (mtyp == STATE_MSG) {
1904                 if (l->peer_caps & TIPC_LINK_PROTO_SEQNO)
1905                         msg_set_seqno(hdr, l->snd_nxt_state++);
1906                 msg_set_seq_gap(hdr, rcvgap);
1907                 bc_rcvgap = link_bc_rcv_gap(bcl);
1908                 msg_set_bc_gap(hdr, bc_rcvgap);
1909                 msg_set_probe(hdr, probe);
1910                 msg_set_is_keepalive(hdr, probe || probe_reply);
1911                 if (l->peer_caps & TIPC_GAP_ACK_BLOCK)
1912                         glen = tipc_build_gap_ack_blks(l, hdr);
1913                 tipc_mon_prep(l->net, data + glen, &dlen, mstate, l->bearer_id);
1914                 msg_set_size(hdr, INT_H_SIZE + glen + dlen);
1915                 skb_trim(skb, INT_H_SIZE + glen + dlen);
1916                 l->stats.sent_states++;
1917                 l->rcv_unacked = 0;
1918         } else {
1919                 /* RESET_MSG or ACTIVATE_MSG */
1920                 if (mtyp == ACTIVATE_MSG) {
1921                         msg_set_dest_session_valid(hdr, 1);
1922                         msg_set_dest_session(hdr, l->peer_session);
1923                 }
1924                 msg_set_max_pkt(hdr, l->advertised_mtu);
1925                 strcpy(data, l->if_name);
1926                 msg_set_size(hdr, INT_H_SIZE + TIPC_MAX_IF_NAME);
1927                 skb_trim(skb, INT_H_SIZE + TIPC_MAX_IF_NAME);
1928         }
1929         if (probe)
1930                 l->stats.sent_probes++;
1931         if (rcvgap)
1932                 l->stats.sent_nacks++;
1933         if (bc_rcvgap)
1934                 bcl->stats.sent_nacks++;
1935         skb->priority = TC_PRIO_CONTROL;
1936         __skb_queue_tail(xmitq, skb);
1937         trace_tipc_proto_build(skb, false, l->name);
1938 }
1939
1940 void tipc_link_create_dummy_tnl_msg(struct tipc_link *l,
1941                                     struct sk_buff_head *xmitq)
1942 {
1943         u32 onode = tipc_own_addr(l->net);
1944         struct tipc_msg *hdr, *ihdr;
1945         struct sk_buff_head tnlq;
1946         struct sk_buff *skb;
1947         u32 dnode = l->addr;
1948
1949         __skb_queue_head_init(&tnlq);
1950         skb = tipc_msg_create(TUNNEL_PROTOCOL, FAILOVER_MSG,
1951                               INT_H_SIZE, BASIC_H_SIZE,
1952                               dnode, onode, 0, 0, 0);
1953         if (!skb) {
1954                 pr_warn("%sunable to create tunnel packet\n", link_co_err);
1955                 return;
1956         }
1957
1958         hdr = buf_msg(skb);
1959         msg_set_msgcnt(hdr, 1);
1960         msg_set_bearer_id(hdr, l->peer_bearer_id);
1961
1962         ihdr = (struct tipc_msg *)msg_data(hdr);
1963         tipc_msg_init(onode, ihdr, TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1964                       BASIC_H_SIZE, dnode);
1965         msg_set_errcode(ihdr, TIPC_ERR_NO_PORT);
1966         __skb_queue_tail(&tnlq, skb);
1967         tipc_link_xmit(l, &tnlq, xmitq);
1968 }
1969
1970 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1971  * with contents of the link's transmit and backlog queues.
1972  */
1973 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1974                            int mtyp, struct sk_buff_head *xmitq)
1975 {
1976         struct sk_buff_head *fdefq = &tnl->failover_deferdq;
1977         struct sk_buff *skb, *tnlskb;
1978         struct tipc_msg *hdr, tnlhdr;
1979         struct sk_buff_head *queue = &l->transmq;
1980         struct sk_buff_head tmpxq, tnlq, frags;
1981         u16 pktlen, pktcnt, seqno = l->snd_nxt;
1982         bool pktcnt_need_update = false;
1983         u16 syncpt;
1984         int rc;
1985
1986         if (!tnl)
1987                 return;
1988
1989         __skb_queue_head_init(&tnlq);
1990         /* Link Synching:
1991          * From now on, send only one single ("dummy") SYNCH message
1992          * to peer. The SYNCH message does not contain any data, just
1993          * a header conveying the synch point to the peer.
1994          */
1995         if (mtyp == SYNCH_MSG && (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
1996                 tnlskb = tipc_msg_create(TUNNEL_PROTOCOL, SYNCH_MSG,
1997                                          INT_H_SIZE, 0, l->addr,
1998                                          tipc_own_addr(l->net),
1999                                          0, 0, 0);
2000                 if (!tnlskb) {
2001                         pr_warn("%sunable to create dummy SYNCH_MSG\n",
2002                                 link_co_err);
2003                         return;
2004                 }
2005
2006                 hdr = buf_msg(tnlskb);
2007                 syncpt = l->snd_nxt + skb_queue_len(&l->backlogq) - 1;
2008                 msg_set_syncpt(hdr, syncpt);
2009                 msg_set_bearer_id(hdr, l->peer_bearer_id);
2010                 __skb_queue_tail(&tnlq, tnlskb);
2011                 tipc_link_xmit(tnl, &tnlq, xmitq);
2012                 return;
2013         }
2014
2015         __skb_queue_head_init(&tmpxq);
2016         __skb_queue_head_init(&frags);
2017         /* At least one packet required for safe algorithm => add dummy */
2018         skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
2019                               BASIC_H_SIZE, 0, l->addr, tipc_own_addr(l->net),
2020                               0, 0, TIPC_ERR_NO_PORT);
2021         if (!skb) {
2022                 pr_warn("%sunable to create tunnel packet\n", link_co_err);
2023                 return;
2024         }
2025         __skb_queue_tail(&tnlq, skb);
2026         tipc_link_xmit(l, &tnlq, &tmpxq);
2027         __skb_queue_purge(&tmpxq);
2028
2029         /* Initialize reusable tunnel packet header */
2030         tipc_msg_init(tipc_own_addr(l->net), &tnlhdr, TUNNEL_PROTOCOL,
2031                       mtyp, INT_H_SIZE, l->addr);
2032         if (mtyp == SYNCH_MSG)
2033                 pktcnt = l->snd_nxt - buf_seqno(skb_peek(&l->transmq));
2034         else
2035                 pktcnt = skb_queue_len(&l->transmq);
2036         pktcnt += skb_queue_len(&l->backlogq);
2037         msg_set_msgcnt(&tnlhdr, pktcnt);
2038         msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
2039 tnl:
2040         /* Wrap each packet into a tunnel packet */
2041         skb_queue_walk(queue, skb) {
2042                 hdr = buf_msg(skb);
2043                 if (queue == &l->backlogq)
2044                         msg_set_seqno(hdr, seqno++);
2045                 pktlen = msg_size(hdr);
2046
2047                 /* Tunnel link MTU is not large enough? This could be
2048                  * due to:
2049                  * 1) Link MTU has just changed or set differently;
2050                  * 2) Or FAILOVER on the top of a SYNCH message
2051                  *
2052                  * The 2nd case should not happen if peer supports
2053                  * TIPC_TUNNEL_ENHANCED
2054                  */
2055                 if (pktlen > tnl->mtu - INT_H_SIZE) {
2056                         if (mtyp == FAILOVER_MSG &&
2057                             (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
2058                                 rc = tipc_msg_fragment(skb, &tnlhdr, tnl->mtu,
2059                                                        &frags);
2060                                 if (rc) {
2061                                         pr_warn("%sunable to frag msg: rc %d\n",
2062                                                 link_co_err, rc);
2063                                         return;
2064                                 }
2065                                 pktcnt += skb_queue_len(&frags) - 1;
2066                                 pktcnt_need_update = true;
2067                                 skb_queue_splice_tail_init(&frags, &tnlq);
2068                                 continue;
2069                         }
2070                         /* Unluckily, peer doesn't have TIPC_TUNNEL_ENHANCED
2071                          * => Just warn it and return!
2072                          */
2073                         pr_warn_ratelimited("%stoo large msg <%d, %d>: %d!\n",
2074                                             link_co_err, msg_user(hdr),
2075                                             msg_type(hdr), msg_size(hdr));
2076                         return;
2077                 }
2078
2079                 msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
2080                 tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE, GFP_ATOMIC);
2081                 if (!tnlskb) {
2082                         pr_warn("%sunable to send packet\n", link_co_err);
2083                         return;
2084                 }
2085                 skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
2086                 skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
2087                 __skb_queue_tail(&tnlq, tnlskb);
2088         }
2089         if (queue != &l->backlogq) {
2090                 queue = &l->backlogq;
2091                 goto tnl;
2092         }
2093
2094         if (pktcnt_need_update)
2095                 skb_queue_walk(&tnlq, skb) {
2096                         hdr = buf_msg(skb);
2097                         msg_set_msgcnt(hdr, pktcnt);
2098                 }
2099
2100         tipc_link_xmit(tnl, &tnlq, xmitq);
2101
2102         if (mtyp == FAILOVER_MSG) {
2103                 tnl->drop_point = l->rcv_nxt;
2104                 tnl->failover_reasm_skb = l->reasm_buf;
2105                 l->reasm_buf = NULL;
2106
2107                 /* Failover the link's deferdq */
2108                 if (unlikely(!skb_queue_empty(fdefq))) {
2109                         pr_warn("Link failover deferdq not empty: %d!\n",
2110                                 skb_queue_len(fdefq));
2111                         __skb_queue_purge(fdefq);
2112                 }
2113                 skb_queue_splice_init(&l->deferdq, fdefq);
2114         }
2115 }
2116
2117 /**
2118  * tipc_link_failover_prepare() - prepare tnl for link failover
2119  *
2120  * This is a special version of the precursor - tipc_link_tnl_prepare(),
2121  * see the tipc_node_link_failover() for details
2122  *
2123  * @l: failover link
2124  * @tnl: tunnel link
2125  * @xmitq: queue for messages to be xmited
2126  */
2127 void tipc_link_failover_prepare(struct tipc_link *l, struct tipc_link *tnl,
2128                                 struct sk_buff_head *xmitq)
2129 {
2130         struct sk_buff_head *fdefq = &tnl->failover_deferdq;
2131
2132         tipc_link_create_dummy_tnl_msg(tnl, xmitq);
2133
2134         /* This failover link endpoint was never established before,
2135          * so it has not received anything from peer.
2136          * Otherwise, it must be a normal failover situation or the
2137          * node has entered SELF_DOWN_PEER_LEAVING and both peer nodes
2138          * would have to start over from scratch instead.
2139          */
2140         tnl->drop_point = 1;
2141         tnl->failover_reasm_skb = NULL;
2142
2143         /* Initiate the link's failover deferdq */
2144         if (unlikely(!skb_queue_empty(fdefq))) {
2145                 pr_warn("Link failover deferdq not empty: %d!\n",
2146                         skb_queue_len(fdefq));
2147                 __skb_queue_purge(fdefq);
2148         }
2149 }
2150
2151 /* tipc_link_validate_msg(): validate message against current link state
2152  * Returns true if message should be accepted, otherwise false
2153  */
2154 bool tipc_link_validate_msg(struct tipc_link *l, struct tipc_msg *hdr)
2155 {
2156         u16 curr_session = l->peer_session;
2157         u16 session = msg_session(hdr);
2158         int mtyp = msg_type(hdr);
2159
2160         if (msg_user(hdr) != LINK_PROTOCOL)
2161                 return true;
2162
2163         switch (mtyp) {
2164         case RESET_MSG:
2165                 if (!l->in_session)
2166                         return true;
2167                 /* Accept only RESET with new session number */
2168                 return more(session, curr_session);
2169         case ACTIVATE_MSG:
2170                 if (!l->in_session)
2171                         return true;
2172                 /* Accept only ACTIVATE with new or current session number */
2173                 return !less(session, curr_session);
2174         case STATE_MSG:
2175                 /* Accept only STATE with current session number */
2176                 if (!l->in_session)
2177                         return false;
2178                 if (session != curr_session)
2179                         return false;
2180                 /* Extra sanity check */
2181                 if (!link_is_up(l) && msg_ack(hdr))
2182                         return false;
2183                 if (!(l->peer_caps & TIPC_LINK_PROTO_SEQNO))
2184                         return true;
2185                 /* Accept only STATE with new sequence number */
2186                 return !less(msg_seqno(hdr), l->rcv_nxt_state);
2187         default:
2188                 return false;
2189         }
2190 }
2191
2192 /* tipc_link_proto_rcv(): receive link level protocol message :
2193  * Note that network plane id propagates through the network, and may
2194  * change at any time. The node with lowest numerical id determines
2195  * network plane
2196  */
2197 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
2198                                struct sk_buff_head *xmitq)
2199 {
2200         struct tipc_msg *hdr = buf_msg(skb);
2201         struct tipc_gap_ack_blks *ga = NULL;
2202         bool reply = msg_probe(hdr), retransmitted = false;
2203         u32 dlen = msg_data_sz(hdr), glen = 0, msg_max;
2204         u16 peers_snd_nxt =  msg_next_sent(hdr);
2205         u16 peers_tol = msg_link_tolerance(hdr);
2206         u16 peers_prio = msg_linkprio(hdr);
2207         u16 gap = msg_seq_gap(hdr);
2208         u16 ack = msg_ack(hdr);
2209         u16 rcv_nxt = l->rcv_nxt;
2210         u16 rcvgap = 0;
2211         int mtyp = msg_type(hdr);
2212         int rc = 0, released;
2213         char *if_name;
2214         void *data;
2215
2216         trace_tipc_proto_rcv(skb, false, l->name);
2217
2218         if (dlen > U16_MAX)
2219                 goto exit;
2220
2221         if (tipc_link_is_blocked(l) || !xmitq)
2222                 goto exit;
2223
2224         if (tipc_own_addr(l->net) > msg_prevnode(hdr))
2225                 l->net_plane = msg_net_plane(hdr);
2226
2227         if (skb_linearize(skb))
2228                 goto exit;
2229
2230         hdr = buf_msg(skb);
2231         data = msg_data(hdr);
2232
2233         if (!tipc_link_validate_msg(l, hdr)) {
2234                 trace_tipc_skb_dump(skb, false, "PROTO invalid (1)!");
2235                 trace_tipc_link_dump(l, TIPC_DUMP_NONE, "PROTO invalid (1)!");
2236                 goto exit;
2237         }
2238
2239         switch (mtyp) {
2240         case RESET_MSG:
2241         case ACTIVATE_MSG:
2242                 msg_max = msg_max_pkt(hdr);
2243                 if (msg_max < tipc_bearer_min_mtu(l->net, l->bearer_id))
2244                         break;
2245                 /* Complete own link name with peer's interface name */
2246                 if_name =  strrchr(l->name, ':') + 1;
2247                 if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
2248                         break;
2249                 if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
2250                         break;
2251                 strncpy(if_name, data, TIPC_MAX_IF_NAME);
2252
2253                 /* Update own tolerance if peer indicates a non-zero value */
2254                 if (tipc_in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2255                         l->tolerance = peers_tol;
2256                         l->bc_rcvlink->tolerance = peers_tol;
2257                 }
2258                 /* Update own priority if peer's priority is higher */
2259                 if (tipc_in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
2260                         l->priority = peers_prio;
2261
2262                 /* If peer is going down we want full re-establish cycle */
2263                 if (msg_peer_stopping(hdr)) {
2264                         rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2265                         break;
2266                 }
2267
2268                 /* If this endpoint was re-created while peer was ESTABLISHING
2269                  * it doesn't know current session number. Force re-synch.
2270                  */
2271                 if (mtyp == ACTIVATE_MSG && msg_dest_session_valid(hdr) &&
2272                     l->session != msg_dest_session(hdr)) {
2273                         if (less(l->session, msg_dest_session(hdr)))
2274                                 l->session = msg_dest_session(hdr) + 1;
2275                         break;
2276                 }
2277
2278                 /* ACTIVATE_MSG serves as PEER_RESET if link is already down */
2279                 if (mtyp == RESET_MSG || !link_is_up(l))
2280                         rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
2281
2282                 /* ACTIVATE_MSG takes up link if it was already locally reset */
2283                 if (mtyp == ACTIVATE_MSG && l->state == LINK_ESTABLISHING)
2284                         rc = TIPC_LINK_UP_EVT;
2285
2286                 l->peer_session = msg_session(hdr);
2287                 l->in_session = true;
2288                 l->peer_bearer_id = msg_bearer_id(hdr);
2289                 if (l->mtu > msg_max)
2290                         l->mtu = msg_max;
2291                 break;
2292
2293         case STATE_MSG:
2294                 /* Validate Gap ACK blocks, drop if invalid */
2295                 glen = tipc_get_gap_ack_blks(&ga, l, hdr, true);
2296                 if (glen > dlen)
2297                         break;
2298
2299                 l->rcv_nxt_state = msg_seqno(hdr) + 1;
2300
2301                 /* Update own tolerance if peer indicates a non-zero value */
2302                 if (tipc_in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2303                         l->tolerance = peers_tol;
2304                         l->bc_rcvlink->tolerance = peers_tol;
2305                 }
2306                 /* Update own prio if peer indicates a different value */
2307                 if ((peers_prio != l->priority) &&
2308                     tipc_in_range(peers_prio, 1, TIPC_MAX_LINK_PRI)) {
2309                         l->priority = peers_prio;
2310                         rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2311                 }
2312
2313                 l->silent_intv_cnt = 0;
2314                 l->stats.recv_states++;
2315                 if (msg_probe(hdr))
2316                         l->stats.recv_probes++;
2317
2318                 if (!link_is_up(l)) {
2319                         if (l->state == LINK_ESTABLISHING)
2320                                 rc = TIPC_LINK_UP_EVT;
2321                         break;
2322                 }
2323
2324                 tipc_mon_rcv(l->net, data + glen, dlen - glen, l->addr,
2325                              &l->mon_state, l->bearer_id);
2326
2327                 /* Send NACK if peer has sent pkts we haven't received yet */
2328                 if ((reply || msg_is_keepalive(hdr)) &&
2329                     more(peers_snd_nxt, rcv_nxt) &&
2330                     !tipc_link_is_synching(l) &&
2331                     skb_queue_empty(&l->deferdq))
2332                         rcvgap = peers_snd_nxt - l->rcv_nxt;
2333                 if (rcvgap || reply)
2334                         tipc_link_build_proto_msg(l, STATE_MSG, 0, reply,
2335                                                   rcvgap, 0, 0, xmitq);
2336
2337                 released = tipc_link_advance_transmq(l, l, ack, gap, ga, xmitq,
2338                                                      &retransmitted, &rc);
2339                 if (gap)
2340                         l->stats.recv_nacks++;
2341                 if (released || retransmitted)
2342                         tipc_link_update_cwin(l, released, retransmitted);
2343                 if (released)
2344                         tipc_link_advance_backlog(l, xmitq);
2345                 if (unlikely(!skb_queue_empty(&l->wakeupq)))
2346                         link_prepare_wakeup(l);
2347         }
2348 exit:
2349         kfree_skb(skb);
2350         return rc;
2351 }
2352
2353 /* tipc_link_build_bc_proto_msg() - create broadcast protocol message
2354  */
2355 static bool tipc_link_build_bc_proto_msg(struct tipc_link *l, bool bcast,
2356                                          u16 peers_snd_nxt,
2357                                          struct sk_buff_head *xmitq)
2358 {
2359         struct sk_buff *skb;
2360         struct tipc_msg *hdr;
2361         struct sk_buff *dfrd_skb = skb_peek(&l->deferdq);
2362         u16 ack = l->rcv_nxt - 1;
2363         u16 gap_to = peers_snd_nxt - 1;
2364
2365         skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
2366                               0, l->addr, tipc_own_addr(l->net), 0, 0, 0);
2367         if (!skb)
2368                 return false;
2369         hdr = buf_msg(skb);
2370         msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
2371         msg_set_bcast_ack(hdr, ack);
2372         msg_set_bcgap_after(hdr, ack);
2373         if (dfrd_skb)
2374                 gap_to = buf_seqno(dfrd_skb) - 1;
2375         msg_set_bcgap_to(hdr, gap_to);
2376         msg_set_non_seq(hdr, bcast);
2377         __skb_queue_tail(xmitq, skb);
2378         return true;
2379 }
2380
2381 /* tipc_link_build_bc_init_msg() - synchronize broadcast link endpoints.
2382  *
2383  * Give a newly added peer node the sequence number where it should
2384  * start receiving and acking broadcast packets.
2385  */
2386 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
2387                                         struct sk_buff_head *xmitq)
2388 {
2389         struct sk_buff_head list;
2390
2391         __skb_queue_head_init(&list);
2392         if (!tipc_link_build_bc_proto_msg(l->bc_rcvlink, false, 0, &list))
2393                 return;
2394         msg_set_bc_ack_invalid(buf_msg(skb_peek(&list)), true);
2395         tipc_link_xmit(l, &list, xmitq);
2396 }
2397
2398 /* tipc_link_bc_init_rcv - receive initial broadcast synch data from peer
2399  */
2400 void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr)
2401 {
2402         int mtyp = msg_type(hdr);
2403         u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2404
2405         if (link_is_up(l))
2406                 return;
2407
2408         if (msg_user(hdr) == BCAST_PROTOCOL) {
2409                 l->rcv_nxt = peers_snd_nxt;
2410                 l->state = LINK_ESTABLISHED;
2411                 return;
2412         }
2413
2414         if (l->peer_caps & TIPC_BCAST_SYNCH)
2415                 return;
2416
2417         if (msg_peer_node_is_up(hdr))
2418                 return;
2419
2420         /* Compatibility: accept older, less safe initial synch data */
2421         if ((mtyp == RESET_MSG) || (mtyp == ACTIVATE_MSG))
2422                 l->rcv_nxt = peers_snd_nxt;
2423 }
2424
2425 /* tipc_link_bc_sync_rcv - update rcv link according to peer's send state
2426  */
2427 int tipc_link_bc_sync_rcv(struct tipc_link *l, struct tipc_msg *hdr,
2428                           struct sk_buff_head *xmitq)
2429 {
2430         u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2431         int rc = 0;
2432
2433         if (!link_is_up(l))
2434                 return rc;
2435
2436         if (!msg_peer_node_is_up(hdr))
2437                 return rc;
2438
2439         /* Open when peer acknowledges our bcast init msg (pkt #1) */
2440         if (msg_ack(hdr))
2441                 l->bc_peer_is_up = true;
2442
2443         if (!l->bc_peer_is_up)
2444                 return rc;
2445
2446         /* Ignore if peers_snd_nxt goes beyond receive window */
2447         if (more(peers_snd_nxt, l->rcv_nxt + l->window))
2448                 return rc;
2449
2450         l->snd_nxt = peers_snd_nxt;
2451         if (link_bc_rcv_gap(l))
2452                 rc |= TIPC_LINK_SND_STATE;
2453
2454         /* Return now if sender supports nack via STATE messages */
2455         if (l->peer_caps & TIPC_BCAST_STATE_NACK)
2456                 return rc;
2457
2458         /* Otherwise, be backwards compatible */
2459
2460         if (!more(peers_snd_nxt, l->rcv_nxt)) {
2461                 l->nack_state = BC_NACK_SND_CONDITIONAL;
2462                 return 0;
2463         }
2464
2465         /* Don't NACK if one was recently sent or peeked */
2466         if (l->nack_state == BC_NACK_SND_SUPPRESS) {
2467                 l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2468                 return 0;
2469         }
2470
2471         /* Conditionally delay NACK sending until next synch rcv */
2472         if (l->nack_state == BC_NACK_SND_CONDITIONAL) {
2473                 l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2474                 if ((peers_snd_nxt - l->rcv_nxt) < TIPC_MIN_LINK_WIN)
2475                         return 0;
2476         }
2477
2478         /* Send NACK now but suppress next one */
2479         tipc_link_build_bc_proto_msg(l, true, peers_snd_nxt, xmitq);
2480         l->nack_state = BC_NACK_SND_SUPPRESS;
2481         return 0;
2482 }
2483
2484 int tipc_link_bc_ack_rcv(struct tipc_link *r, u16 acked, u16 gap,
2485                          struct tipc_gap_ack_blks *ga,
2486                          struct sk_buff_head *xmitq,
2487                          struct sk_buff_head *retrq)
2488 {
2489         struct tipc_link *l = r->bc_sndlink;
2490         bool unused = false;
2491         int rc = 0;
2492
2493         if (!link_is_up(r) || !r->bc_peer_is_up)
2494                 return 0;
2495
2496         if (gap) {
2497                 l->stats.recv_nacks++;
2498                 r->stats.recv_nacks++;
2499         }
2500
2501         if (less(acked, r->acked) || (acked == r->acked && !gap && !ga))
2502                 return 0;
2503
2504         trace_tipc_link_bc_ack(r, acked, gap, &l->transmq);
2505         tipc_link_advance_transmq(l, r, acked, gap, ga, retrq, &unused, &rc);
2506
2507         tipc_link_advance_backlog(l, xmitq);
2508         if (unlikely(!skb_queue_empty(&l->wakeupq)))
2509                 link_prepare_wakeup(l);
2510
2511         return rc;
2512 }
2513
2514 /* tipc_link_bc_nack_rcv(): receive broadcast nack message
2515  * This function is here for backwards compatibility, since
2516  * no BCAST_PROTOCOL/STATE messages occur from TIPC v2.5.
2517  */
2518 int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
2519                           struct sk_buff_head *xmitq)
2520 {
2521         struct tipc_msg *hdr = buf_msg(skb);
2522         u32 dnode = msg_destnode(hdr);
2523         int mtyp = msg_type(hdr);
2524         u16 acked = msg_bcast_ack(hdr);
2525         u16 from = acked + 1;
2526         u16 to = msg_bcgap_to(hdr);
2527         u16 peers_snd_nxt = to + 1;
2528         int rc = 0;
2529
2530         kfree_skb(skb);
2531
2532         if (!tipc_link_is_up(l) || !l->bc_peer_is_up)
2533                 return 0;
2534
2535         if (mtyp != STATE_MSG)
2536                 return 0;
2537
2538         if (dnode == tipc_own_addr(l->net)) {
2539                 rc = tipc_link_bc_ack_rcv(l, acked, to - acked, NULL, xmitq,
2540                                           xmitq);
2541                 l->stats.recv_nacks++;
2542                 return rc;
2543         }
2544
2545         /* Msg for other node => suppress own NACK at next sync if applicable */
2546         if (more(peers_snd_nxt, l->rcv_nxt) && !less(l->rcv_nxt, from))
2547                 l->nack_state = BC_NACK_SND_SUPPRESS;
2548
2549         return 0;
2550 }
2551
2552 void tipc_link_set_queue_limits(struct tipc_link *l, u32 min_win, u32 max_win)
2553 {
2554         int max_bulk = TIPC_MAX_PUBL / (l->mtu / ITEM_SIZE);
2555
2556         l->min_win = min_win;
2557         l->ssthresh = max_win;
2558         l->max_win = max_win;
2559         l->window = min_win;
2560         l->backlog[TIPC_LOW_IMPORTANCE].limit      = min_win * 2;
2561         l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = min_win * 4;
2562         l->backlog[TIPC_HIGH_IMPORTANCE].limit     = min_win * 6;
2563         l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = min_win * 8;
2564         l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
2565 }
2566
2567 /**
2568  * tipc_link_reset_stats - reset link statistics
2569  * @l: pointer to link
2570  */
2571 void tipc_link_reset_stats(struct tipc_link *l)
2572 {
2573         memset(&l->stats, 0, sizeof(l->stats));
2574 }
2575
2576 static void link_print(struct tipc_link *l, const char *str)
2577 {
2578         struct sk_buff *hskb = skb_peek(&l->transmq);
2579         u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt - 1;
2580         u16 tail = l->snd_nxt - 1;
2581
2582         pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
2583         pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
2584                 skb_queue_len(&l->transmq), head, tail,
2585                 skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
2586 }
2587
2588 /* Parse and validate nested (link) properties valid for media, bearer and link
2589  */
2590 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
2591 {
2592         int err;
2593
2594         err = nla_parse_nested_deprecated(props, TIPC_NLA_PROP_MAX, prop,
2595                                           tipc_nl_prop_policy, NULL);
2596         if (err)
2597                 return err;
2598
2599         if (props[TIPC_NLA_PROP_PRIO]) {
2600                 u32 prio;
2601
2602                 prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
2603                 if (prio > TIPC_MAX_LINK_PRI)
2604                         return -EINVAL;
2605         }
2606
2607         if (props[TIPC_NLA_PROP_TOL]) {
2608                 u32 tol;
2609
2610                 tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
2611                 if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
2612                         return -EINVAL;
2613         }
2614
2615         if (props[TIPC_NLA_PROP_WIN]) {
2616                 u32 max_win;
2617
2618                 max_win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2619                 if (max_win < TIPC_DEF_LINK_WIN || max_win > TIPC_MAX_LINK_WIN)
2620                         return -EINVAL;
2621         }
2622
2623         return 0;
2624 }
2625
2626 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
2627 {
2628         int i;
2629         struct nlattr *stats;
2630
2631         struct nla_map {
2632                 u32 key;
2633                 u32 val;
2634         };
2635
2636         struct nla_map map[] = {
2637                 {TIPC_NLA_STATS_RX_INFO, 0},
2638                 {TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
2639                 {TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
2640                 {TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
2641                 {TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
2642                 {TIPC_NLA_STATS_TX_INFO, 0},
2643                 {TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
2644                 {TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
2645                 {TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
2646                 {TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
2647                 {TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
2648                         s->msg_length_counts : 1},
2649                 {TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
2650                 {TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
2651                 {TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
2652                 {TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
2653                 {TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
2654                 {TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
2655                 {TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
2656                 {TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
2657                 {TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
2658                 {TIPC_NLA_STATS_RX_STATES, s->recv_states},
2659                 {TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
2660                 {TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
2661                 {TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
2662                 {TIPC_NLA_STATS_TX_STATES, s->sent_states},
2663                 {TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
2664                 {TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
2665                 {TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
2666                 {TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
2667                 {TIPC_NLA_STATS_DUPLICATES, s->duplicates},
2668                 {TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
2669                 {TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
2670                 {TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
2671                         (s->accu_queue_sz / s->queue_sz_counts) : 0}
2672         };
2673
2674         stats = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2675         if (!stats)
2676                 return -EMSGSIZE;
2677
2678         for (i = 0; i <  ARRAY_SIZE(map); i++)
2679                 if (nla_put_u32(skb, map[i].key, map[i].val))
2680                         goto msg_full;
2681
2682         nla_nest_end(skb, stats);
2683
2684         return 0;
2685 msg_full:
2686         nla_nest_cancel(skb, stats);
2687
2688         return -EMSGSIZE;
2689 }
2690
2691 /* Caller should hold appropriate locks to protect the link */
2692 int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2693                        struct tipc_link *link, int nlflags)
2694 {
2695         u32 self = tipc_own_addr(net);
2696         struct nlattr *attrs;
2697         struct nlattr *prop;
2698         void *hdr;
2699         int err;
2700
2701         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2702                           nlflags, TIPC_NL_LINK_GET);
2703         if (!hdr)
2704                 return -EMSGSIZE;
2705
2706         attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2707         if (!attrs)
2708                 goto msg_full;
2709
2710         if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2711                 goto attr_msg_full;
2712         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST, tipc_cluster_mask(self)))
2713                 goto attr_msg_full;
2714         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
2715                 goto attr_msg_full;
2716         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->stats.recv_pkts))
2717                 goto attr_msg_full;
2718         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->stats.sent_pkts))
2719                 goto attr_msg_full;
2720
2721         if (tipc_link_is_up(link))
2722                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2723                         goto attr_msg_full;
2724         if (link->active)
2725                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2726                         goto attr_msg_full;
2727
2728         prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2729         if (!prop)
2730                 goto attr_msg_full;
2731         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2732                 goto prop_msg_full;
2733         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2734                 goto prop_msg_full;
2735         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2736                         link->window))
2737                 goto prop_msg_full;
2738         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2739                 goto prop_msg_full;
2740         nla_nest_end(msg->skb, prop);
2741
2742         err = __tipc_nl_add_stats(msg->skb, &link->stats);
2743         if (err)
2744                 goto attr_msg_full;
2745
2746         nla_nest_end(msg->skb, attrs);
2747         genlmsg_end(msg->skb, hdr);
2748
2749         return 0;
2750
2751 prop_msg_full:
2752         nla_nest_cancel(msg->skb, prop);
2753 attr_msg_full:
2754         nla_nest_cancel(msg->skb, attrs);
2755 msg_full:
2756         genlmsg_cancel(msg->skb, hdr);
2757
2758         return -EMSGSIZE;
2759 }
2760
2761 static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
2762                                       struct tipc_stats *stats)
2763 {
2764         int i;
2765         struct nlattr *nest;
2766
2767         struct nla_map {
2768                 __u32 key;
2769                 __u32 val;
2770         };
2771
2772         struct nla_map map[] = {
2773                 {TIPC_NLA_STATS_RX_INFO, stats->recv_pkts},
2774                 {TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
2775                 {TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
2776                 {TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
2777                 {TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
2778                 {TIPC_NLA_STATS_TX_INFO, stats->sent_pkts},
2779                 {TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
2780                 {TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
2781                 {TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
2782                 {TIPC_NLA_STATS_TX_BUNDLED, stats->sent_bundled},
2783                 {TIPC_NLA_STATS_RX_NACKS, stats->recv_nacks},
2784                 {TIPC_NLA_STATS_RX_DEFERRED, stats->deferred_recv},
2785                 {TIPC_NLA_STATS_TX_NACKS, stats->sent_nacks},
2786                 {TIPC_NLA_STATS_TX_ACKS, stats->sent_acks},
2787                 {TIPC_NLA_STATS_RETRANSMITTED, stats->retransmitted},
2788                 {TIPC_NLA_STATS_DUPLICATES, stats->duplicates},
2789                 {TIPC_NLA_STATS_LINK_CONGS, stats->link_congs},
2790                 {TIPC_NLA_STATS_MAX_QUEUE, stats->max_queue_sz},
2791                 {TIPC_NLA_STATS_AVG_QUEUE, stats->queue_sz_counts ?
2792                         (stats->accu_queue_sz / stats->queue_sz_counts) : 0}
2793         };
2794
2795         nest = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2796         if (!nest)
2797                 return -EMSGSIZE;
2798
2799         for (i = 0; i <  ARRAY_SIZE(map); i++)
2800                 if (nla_put_u32(skb, map[i].key, map[i].val))
2801                         goto msg_full;
2802
2803         nla_nest_end(skb, nest);
2804
2805         return 0;
2806 msg_full:
2807         nla_nest_cancel(skb, nest);
2808
2809         return -EMSGSIZE;
2810 }
2811
2812 int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg,
2813                         struct tipc_link *bcl)
2814 {
2815         int err;
2816         void *hdr;
2817         struct nlattr *attrs;
2818         struct nlattr *prop;
2819         u32 bc_mode = tipc_bcast_get_mode(net);
2820         u32 bc_ratio = tipc_bcast_get_broadcast_ratio(net);
2821
2822         if (!bcl)
2823                 return 0;
2824
2825         tipc_bcast_lock(net);
2826
2827         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2828                           NLM_F_MULTI, TIPC_NL_LINK_GET);
2829         if (!hdr) {
2830                 tipc_bcast_unlock(net);
2831                 return -EMSGSIZE;
2832         }
2833
2834         attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2835         if (!attrs)
2836                 goto msg_full;
2837
2838         /* The broadcast link is always up */
2839         if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2840                 goto attr_msg_full;
2841
2842         if (nla_put_flag(msg->skb, TIPC_NLA_LINK_BROADCAST))
2843                 goto attr_msg_full;
2844         if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
2845                 goto attr_msg_full;
2846         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, 0))
2847                 goto attr_msg_full;
2848         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, 0))
2849                 goto attr_msg_full;
2850
2851         prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2852         if (!prop)
2853                 goto attr_msg_full;
2854         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, bcl->max_win))
2855                 goto prop_msg_full;
2856         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST, bc_mode))
2857                 goto prop_msg_full;
2858         if (bc_mode & BCLINK_MODE_SEL)
2859                 if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST_RATIO,
2860                                 bc_ratio))
2861                         goto prop_msg_full;
2862         nla_nest_end(msg->skb, prop);
2863
2864         err = __tipc_nl_add_bc_link_stat(msg->skb, &bcl->stats);
2865         if (err)
2866                 goto attr_msg_full;
2867
2868         tipc_bcast_unlock(net);
2869         nla_nest_end(msg->skb, attrs);
2870         genlmsg_end(msg->skb, hdr);
2871
2872         return 0;
2873
2874 prop_msg_full:
2875         nla_nest_cancel(msg->skb, prop);
2876 attr_msg_full:
2877         nla_nest_cancel(msg->skb, attrs);
2878 msg_full:
2879         tipc_bcast_unlock(net);
2880         genlmsg_cancel(msg->skb, hdr);
2881
2882         return -EMSGSIZE;
2883 }
2884
2885 void tipc_link_set_tolerance(struct tipc_link *l, u32 tol,
2886                              struct sk_buff_head *xmitq)
2887 {
2888         l->tolerance = tol;
2889         if (l->bc_rcvlink)
2890                 l->bc_rcvlink->tolerance = tol;
2891         if (link_is_up(l))
2892                 tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, tol, 0, xmitq);
2893 }
2894
2895 void tipc_link_set_prio(struct tipc_link *l, u32 prio,
2896                         struct sk_buff_head *xmitq)
2897 {
2898         l->priority = prio;
2899         tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, prio, xmitq);
2900 }
2901
2902 void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit)
2903 {
2904         l->abort_limit = limit;
2905 }
2906
2907 /**
2908  * tipc_link_dump - dump TIPC link data
2909  * @l: tipc link to be dumped
2910  * @dqueues: bitmask to decide if any link queue to be dumped?
2911  *           - TIPC_DUMP_NONE: don't dump link queues
2912  *           - TIPC_DUMP_TRANSMQ: dump link transmq queue
2913  *           - TIPC_DUMP_BACKLOGQ: dump link backlog queue
2914  *           - TIPC_DUMP_DEFERDQ: dump link deferd queue
2915  *           - TIPC_DUMP_INPUTQ: dump link input queue
2916  *           - TIPC_DUMP_WAKEUP: dump link wakeup queue
2917  *           - TIPC_DUMP_ALL: dump all the link queues above
2918  * @buf: returned buffer of dump data in format
2919  */
2920 int tipc_link_dump(struct tipc_link *l, u16 dqueues, char *buf)
2921 {
2922         int i = 0;
2923         size_t sz = (dqueues) ? LINK_LMAX : LINK_LMIN;
2924         struct sk_buff_head *list;
2925         struct sk_buff *hskb, *tskb;
2926         u32 len;
2927
2928         if (!l) {
2929                 i += scnprintf(buf, sz, "link data: (null)\n");
2930                 return i;
2931         }
2932
2933         i += scnprintf(buf, sz, "link data: %x", l->addr);
2934         i += scnprintf(buf + i, sz - i, " %x", l->state);
2935         i += scnprintf(buf + i, sz - i, " %u", l->in_session);
2936         i += scnprintf(buf + i, sz - i, " %u", l->session);
2937         i += scnprintf(buf + i, sz - i, " %u", l->peer_session);
2938         i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt);
2939         i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt);
2940         i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt_state);
2941         i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt_state);
2942         i += scnprintf(buf + i, sz - i, " %x", l->peer_caps);
2943         i += scnprintf(buf + i, sz - i, " %u", l->silent_intv_cnt);
2944         i += scnprintf(buf + i, sz - i, " %u", l->rst_cnt);
2945         i += scnprintf(buf + i, sz - i, " %u", 0);
2946         i += scnprintf(buf + i, sz - i, " %u", 0);
2947         i += scnprintf(buf + i, sz - i, " %u", l->acked);
2948
2949         list = &l->transmq;
2950         len = skb_queue_len(list);
2951         hskb = skb_peek(list);
2952         tskb = skb_peek_tail(list);
2953         i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2954                        (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2955                        (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2956
2957         list = &l->deferdq;
2958         len = skb_queue_len(list);
2959         hskb = skb_peek(list);
2960         tskb = skb_peek_tail(list);
2961         i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2962                        (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2963                        (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2964
2965         list = &l->backlogq;
2966         len = skb_queue_len(list);
2967         hskb = skb_peek(list);
2968         tskb = skb_peek_tail(list);
2969         i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2970                        (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2971                        (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2972
2973         list = l->inputq;
2974         len = skb_queue_len(list);
2975         hskb = skb_peek(list);
2976         tskb = skb_peek_tail(list);
2977         i += scnprintf(buf + i, sz - i, " | %u %u %u\n", len,
2978                        (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2979                        (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2980
2981         if (dqueues & TIPC_DUMP_TRANSMQ) {
2982                 i += scnprintf(buf + i, sz - i, "transmq: ");
2983                 i += tipc_list_dump(&l->transmq, false, buf + i);
2984         }
2985         if (dqueues & TIPC_DUMP_BACKLOGQ) {
2986                 i += scnprintf(buf + i, sz - i,
2987                                "backlogq: <%u %u %u %u %u>, ",
2988                                l->backlog[TIPC_LOW_IMPORTANCE].len,
2989                                l->backlog[TIPC_MEDIUM_IMPORTANCE].len,
2990                                l->backlog[TIPC_HIGH_IMPORTANCE].len,
2991                                l->backlog[TIPC_CRITICAL_IMPORTANCE].len,
2992                                l->backlog[TIPC_SYSTEM_IMPORTANCE].len);
2993                 i += tipc_list_dump(&l->backlogq, false, buf + i);
2994         }
2995         if (dqueues & TIPC_DUMP_DEFERDQ) {
2996                 i += scnprintf(buf + i, sz - i, "deferdq: ");
2997                 i += tipc_list_dump(&l->deferdq, false, buf + i);
2998         }
2999         if (dqueues & TIPC_DUMP_INPUTQ) {
3000                 i += scnprintf(buf + i, sz - i, "inputq: ");
3001                 i += tipc_list_dump(l->inputq, false, buf + i);
3002         }
3003         if (dqueues & TIPC_DUMP_WAKEUP) {
3004                 i += scnprintf(buf + i, sz - i, "wakeup: ");
3005                 i += tipc_list_dump(&l->wakeupq, false, buf + i);
3006         }
3007
3008         return i;
3009 }