net/tipc/link.c

   1 /*
   2  * net/tipc/link.c: TIPC link code
   3  *
   4  * Copyright (c) 1996-2007, Ericsson AB
   5  * Copyright (c) 2004-2007, 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 "dbg.h"
  39 #include "link.h"
  40 #include "net.h"
  41 #include "node.h"
  42 #include "port.h"
  43 #include "addr.h"
  44 #include "node_subscr.h"
  45 #include "name_distr.h"
  46 #include "bearer.h"
  47 #include "name_table.h"
  48 #include "discover.h"
  49 #include "config.h"
  50 #include "bcast.h"
  51
  52
  53 /*
  54  * Limit for deferred reception queue:
  55  */
  56
  57 #define DEF_QUEUE_LIMIT 256u
  58
  59 /*
  60  * Link state events:
  61  */
  62
  63 #define  STARTING_EVT    856384768      /* link processing trigger */
  64 #define  TRAFFIC_MSG_EVT 560815u        /* rx'd ??? */
  65 #define  TIMEOUT_EVT     560817u        /* link timer expired */
  66
  67 /*
  68  * The following two 'message types' is really just implementation
  69  * data conveniently stored in the message header.
  70  * They must not be considered part of the protocol
  71  */
  72 #define OPEN_MSG   0
  73 #define CLOSED_MSG 1
  74
  75 /*
  76  * State value stored in 'exp_msg_count'
  77  */
  78
  79 #define START_CHANGEOVER 100000u
  80
  81 /**
  82  * struct link_name - deconstructed link name
  83  * @addr_local: network address of node at this end
  84  * @if_local: name of interface at this end
  85  * @addr_peer: network address of node at far end
  86  * @if_peer: name of interface at far end
  87  */
  88
  89 struct link_name {
  90         u32 addr_local;
  91         char if_local[TIPC_MAX_IF_NAME];
  92         u32 addr_peer;
  93         char if_peer[TIPC_MAX_IF_NAME];
  94 };
  95
  96 #if 0
  97
  98 /* LINK EVENT CODE IS NOT SUPPORTED AT PRESENT */
  99
 100 /**
 101  * struct link_event - link up/down event notification
 102  */
 103
 104 struct link_event {
 105         u32 addr;
 106         int up;
 107         void (*fcn)(u32, char *, int);
 108         char name[TIPC_MAX_LINK_NAME];
 109 };
 110
 111 #endif
 112
 113 static void link_handle_out_of_seq_msg(struct link *l_ptr,
 114                                        struct sk_buff *buf);
 115 static void link_recv_proto_msg(struct link *l_ptr, struct sk_buff *buf);
 116 static int  link_recv_changeover_msg(struct link **l_ptr, struct sk_buff **buf);
 117 static void link_set_supervision_props(struct link *l_ptr, u32 tolerance);
 118 static int  link_send_sections_long(struct port *sender,
 119                                     struct iovec const *msg_sect,
 120                                     u32 num_sect, u32 destnode);
 121 static void link_check_defragm_bufs(struct link *l_ptr);
 122 static void link_state_event(struct link *l_ptr, u32 event);
 123 static void link_reset_statistics(struct link *l_ptr);
 124 static void link_print(struct link *l_ptr, struct print_buf *buf,
 125                        const char *str);
 126
 127 /*
 128  * Debugging code used by link routines only
 129  *
 130  * When debugging link problems on a system that has multiple links,
 131  * the standard TIPC debugging routines may not be useful since they
 132  * allow the output from multiple links to be intermixed.  For this reason
 133  * routines of the form "dbg_link_XXX()" have been created that will capture
 134  * debug info into a link's personal print buffer, which can then be dumped
 135  * into the TIPC system log (TIPC_LOG) upon request.
 136  *
 137  * To enable per-link debugging, use LINK_LOG_BUF_SIZE to specify the size
 138  * of the print buffer used by each link.  If LINK_LOG_BUF_SIZE is set to 0,
 139  * the dbg_link_XXX() routines simply send their output to the standard
 140  * debug print buffer (DBG_OUTPUT), if it has been defined; this can be useful
 141  * when there is only a single link in the system being debugged.
 142  *
 143  * Notes:
 144  * - When enabled, LINK_LOG_BUF_SIZE should be set to at least TIPC_PB_MIN_SIZE
 145  * - "l_ptr" must be valid when using dbg_link_XXX() macros
 146  */
 147
 148 #define LINK_LOG_BUF_SIZE 0
 149
 150 #define dbg_link(fmt, arg...)  do {if (LINK_LOG_BUF_SIZE) tipc_printf(&l_ptr->print_buf, fmt, ## arg); } while(0)
 151 #define dbg_link_msg(msg, txt) do {if (LINK_LOG_BUF_SIZE) tipc_msg_print(&l_ptr->print_buf, msg, txt); } while(0)
 152 #define dbg_link_state(txt) do {if (LINK_LOG_BUF_SIZE) link_print(l_ptr, &l_ptr->print_buf, txt); } while(0)
 153 #define dbg_link_dump() do { \
 154         if (LINK_LOG_BUF_SIZE) { \
 155                 tipc_printf(LOG, "\n\nDumping link <%s>:\n", l_ptr->name); \
 156                 tipc_printbuf_move(LOG, &l_ptr->print_buf); \
 157         } \
 158 } while (0)
 159
 160 static void dbg_print_link(struct link *l_ptr, const char *str)
 161 {
 162         if (DBG_OUTPUT != TIPC_NULL)
 163                 link_print(l_ptr, DBG_OUTPUT, str);
 164 }
 165
 166 static void dbg_print_buf_chain(struct sk_buff *root_buf)
 167 {
 168         if (DBG_OUTPUT != TIPC_NULL) {
 169                 struct sk_buff *buf = root_buf;
 170
 171                 while (buf) {
 172                         msg_dbg(buf_msg(buf), "In chain: ");
 173                         buf = buf->next;
 174                 }
 175         }
 176 }
 177
 178 /*
 179  *  Simple link routines
 180  */
 181
 182 static unsigned int align(unsigned int i)
 183 {
 184         return (i + 3) & ~3u;
 185 }
 186
 187 static int link_working_working(struct link *l_ptr)
 188 {
 189         return (l_ptr->state == WORKING_WORKING);
 190 }
 191
 192 static int link_working_unknown(struct link *l_ptr)
 193 {
 194         return (l_ptr->state == WORKING_UNKNOWN);
 195 }
 196
 197 static int link_reset_unknown(struct link *l_ptr)
 198 {
 199         return (l_ptr->state == RESET_UNKNOWN);
 200 }
 201
 202 static int link_reset_reset(struct link *l_ptr)
 203 {
 204         return (l_ptr->state == RESET_RESET);
 205 }
 206
 207 static int link_blocked(struct link *l_ptr)
 208 {
 209         return (l_ptr->exp_msg_count || l_ptr->blocked);
 210 }
 211
 212 static int link_congested(struct link *l_ptr)
 213 {
 214         return (l_ptr->out_queue_size >= l_ptr->queue_limit[0]);
 215 }
 216
 217 static u32 link_max_pkt(struct link *l_ptr)
 218 {
 219         return l_ptr->max_pkt;
 220 }
 221
 222 static void link_init_max_pkt(struct link *l_ptr)
 223 {
 224         u32 max_pkt;
 225
 226         max_pkt = (l_ptr->b_ptr->publ.mtu & ~3);
 227         if (max_pkt > MAX_MSG_SIZE)
 228                 max_pkt = MAX_MSG_SIZE;
 229
 230         l_ptr->max_pkt_target = max_pkt;
 231         if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
 232                 l_ptr->max_pkt = l_ptr->max_pkt_target;
 233         else
 234                 l_ptr->max_pkt = MAX_PKT_DEFAULT;
 235
 236         l_ptr->max_pkt_probes = 0;
 237 }
 238
 239 static u32 link_next_sent(struct link *l_ptr)
 240 {
 241         if (l_ptr->next_out)
 242                 return msg_seqno(buf_msg(l_ptr->next_out));
 243         return mod(l_ptr->next_out_no);
 244 }
 245
 246 static u32 link_last_sent(struct link *l_ptr)
 247 {
 248         return mod(link_next_sent(l_ptr) - 1);
 249 }
 250
 251 /*
 252  *  Simple non-static link routines (i.e. referenced outside this file)
 253  */
 254
 255 int tipc_link_is_up(struct link *l_ptr)
 256 {
 257         if (!l_ptr)
 258                 return 0;
 259         return (link_working_working(l_ptr) || link_working_unknown(l_ptr));
 260 }
 261
 262 int tipc_link_is_active(struct link *l_ptr)
 263 {
 264         return ((l_ptr->owner->active_links[0] == l_ptr) ||
 265                 (l_ptr->owner->active_links[1] == l_ptr));
 266 }
 267
 268 /**
 269  * link_name_validate - validate & (optionally) deconstruct link name
 270  * @name - ptr to link name string
 271  * @name_parts - ptr to area for link name components (or NULL if not needed)
 272  *
 273  * Returns 1 if link name is valid, otherwise 0.
 274  */
 275
 276 static int link_name_validate(const char *name, struct link_name *name_parts)
 277 {
 278         char name_copy[TIPC_MAX_LINK_NAME];
 279         char *addr_local;
 280         char *if_local;
 281         char *addr_peer;
 282         char *if_peer;
 283         char dummy;
 284         u32 z_local, c_local, n_local;
 285         u32 z_peer, c_peer, n_peer;
 286         u32 if_local_len;
 287         u32 if_peer_len;
 288
 289         /* copy link name & ensure length is OK */
 290
 291         name_copy[TIPC_MAX_LINK_NAME - 1] = 0;
 292         /* need above in case non-Posix strncpy() doesn't pad with nulls */
 293         strncpy(name_copy, name, TIPC_MAX_LINK_NAME);
 294         if (name_copy[TIPC_MAX_LINK_NAME - 1] != 0)
 295                 return 0;
 296
 297         /* ensure all component parts of link name are present */
 298
 299         addr_local = name_copy;
 300         if ((if_local = strchr(addr_local, ':')) == NULL)
 301                 return 0;
 302         *(if_local++) = 0;
 303         if ((addr_peer = strchr(if_local, '-')) == NULL)
 304                 return 0;
 305         *(addr_peer++) = 0;
 306         if_local_len = addr_peer - if_local;
 307         if ((if_peer = strchr(addr_peer, ':')) == NULL)
 308                 return 0;
 309         *(if_peer++) = 0;
 310         if_peer_len = strlen(if_peer) + 1;
 311
 312         /* validate component parts of link name */
 313
 314         if ((sscanf(addr_local, "%u.%u.%u%c",
 315                     &z_local, &c_local, &n_local, &dummy) != 3) ||
 316             (sscanf(addr_peer, "%u.%u.%u%c",
 317                     &z_peer, &c_peer, &n_peer, &dummy) != 3) ||
 318             (z_local > 255) || (c_local > 4095) || (n_local > 4095) ||
 319             (z_peer  > 255) || (c_peer  > 4095) || (n_peer  > 4095) ||
 320             (if_local_len <= 1) || (if_local_len > TIPC_MAX_IF_NAME) ||
 321             (if_peer_len  <= 1) || (if_peer_len  > TIPC_MAX_IF_NAME) ||
 322             (strspn(if_local, tipc_alphabet) != (if_local_len - 1)) ||
 323             (strspn(if_peer, tipc_alphabet) != (if_peer_len - 1)))
 324                 return 0;
 325
 326         /* return link name components, if necessary */
 327
 328         if (name_parts) {
 329                 name_parts->addr_local = tipc_addr(z_local, c_local, n_local);
 330                 strcpy(name_parts->if_local, if_local);
 331                 name_parts->addr_peer = tipc_addr(z_peer, c_peer, n_peer);
 332                 strcpy(name_parts->if_peer, if_peer);
 333         }
 334         return 1;
 335 }
 336
 337 /**
 338  * link_timeout - handle expiration of link timer
 339  * @l_ptr: pointer to link
 340  *
 341  * This routine must not grab "tipc_net_lock" to avoid a potential deadlock conflict
 342  * with tipc_link_delete().  (There is no risk that the node will be deleted by
 343  * another thread because tipc_link_delete() always cancels the link timer before
 344  * tipc_node_delete() is called.)
 345  */
 346
 347 static void link_timeout(struct link *l_ptr)
 348 {
 349         tipc_node_lock(l_ptr->owner);
 350
 351         /* update counters used in statistical profiling of send traffic */
 352
 353         l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
 354         l_ptr->stats.queue_sz_counts++;
 355
 356         if (l_ptr->out_queue_size > l_ptr->stats.max_queue_sz)
 357                 l_ptr->stats.max_queue_sz = l_ptr->out_queue_size;
 358
 359         if (l_ptr->first_out) {
 360                 struct tipc_msg *msg = buf_msg(l_ptr->first_out);
 361                 u32 length = msg_size(msg);
 362
 363                 if ((msg_user(msg) == MSG_FRAGMENTER)
 364                     && (msg_type(msg) == FIRST_FRAGMENT)) {
 365                         length = msg_size(msg_get_wrapped(msg));
 366                 }
 367                 if (length) {
 368                         l_ptr->stats.msg_lengths_total += length;
 369                         l_ptr->stats.msg_length_counts++;
 370                         if (length <= 64)
 371                                 l_ptr->stats.msg_length_profile[0]++;
 372                         else if (length <= 256)
 373                                 l_ptr->stats.msg_length_profile[1]++;
 374                         else if (length <= 1024)
 375                                 l_ptr->stats.msg_length_profile[2]++;
 376                         else if (length <= 4096)
 377                                 l_ptr->stats.msg_length_profile[3]++;
 378                         else if (length <= 16384)
 379                                 l_ptr->stats.msg_length_profile[4]++;
 380                         else if (length <= 32768)
 381                                 l_ptr->stats.msg_length_profile[5]++;
 382                         else
 383                                 l_ptr->stats.msg_length_profile[6]++;
 384                 }
 385         }
 386
 387         /* do all other link processing performed on a periodic basis */
 388
 389         link_check_defragm_bufs(l_ptr);
 390
 391         link_state_event(l_ptr, TIMEOUT_EVT);
 392
 393         if (l_ptr->next_out)
 394                 tipc_link_push_queue(l_ptr);
 395
 396         tipc_node_unlock(l_ptr->owner);
 397 }
 398
 399 static void link_set_timer(struct link *l_ptr, u32 time)
 400 {
 401         k_start_timer(&l_ptr->timer, time);
 402 }
 403
 404 /**
 405  * tipc_link_create - create a new link
 406  * @b_ptr: pointer to associated bearer
 407  * @peer: network address of node at other end of link
 408  * @media_addr: media address to use when sending messages over link
 409  *
 410  * Returns pointer to link.
 411  */
 412
 413 struct link *tipc_link_create(struct bearer *b_ptr, const u32 peer,
 414                               const struct tipc_media_addr *media_addr)
 415 {
 416         struct link *l_ptr;
 417         struct tipc_msg *msg;
 418         char *if_name;
 419
 420         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 421         if (!l_ptr) {
 422                 warn("Link creation failed, no memory\n");
 423                 return NULL;
 424         }
 425
 426         if (LINK_LOG_BUF_SIZE) {
 427                 char *pb = kmalloc(LINK_LOG_BUF_SIZE, GFP_ATOMIC);
 428
 429                 if (!pb) {
 430                         kfree(l_ptr);
 431                         warn("Link creation failed, no memory for print buffer\n");
 432                         return NULL;
 433                 }
 434                 tipc_printbuf_init(&l_ptr->print_buf, pb, LINK_LOG_BUF_SIZE);
 435         }
 436
 437         l_ptr->addr = peer;
 438         if_name = strchr(b_ptr->publ.name, ':') + 1;
 439         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:",
 440                 tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
 441                 tipc_node(tipc_own_addr),
 442                 if_name,
 443                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 444                 /* note: peer i/f is appended to link name by reset/activate */
 445         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 446         l_ptr->checkpoint = 1;
 447         l_ptr->b_ptr = b_ptr;
 448         link_set_supervision_props(l_ptr, b_ptr->media->tolerance);
 449         l_ptr->state = RESET_UNKNOWN;
 450
 451         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 452         msg = l_ptr->pmsg;
 453         msg_init(msg, LINK_PROTOCOL, RESET_MSG, TIPC_OK, INT_H_SIZE, l_ptr->addr);
 454         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 455         msg_set_session(msg, tipc_random);
 456         msg_set_bearer_id(msg, b_ptr->identity);
 457         strcpy((char *)msg_data(msg), if_name);
 458
 459         l_ptr->priority = b_ptr->priority;
 460         tipc_link_set_queue_limits(l_ptr, b_ptr->media->window);
 461
 462         link_init_max_pkt(l_ptr);
 463
 464         l_ptr->next_out_no = 1;
 465         INIT_LIST_HEAD(&l_ptr->waiting_ports);
 466
 467         link_reset_statistics(l_ptr);
 468
 469         l_ptr->owner = tipc_node_attach_link(l_ptr);
 470         if (!l_ptr->owner) {
 471                 if (LINK_LOG_BUF_SIZE)
 472                         kfree(l_ptr->print_buf.buf);
 473                 kfree(l_ptr);
 474                 return NULL;
 475         }
 476
 477         k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
 478         list_add_tail(&l_ptr->link_list, &b_ptr->links);
 479         tipc_k_signal((Handler)tipc_link_start, (unsigned long)l_ptr);
 480
 481         dbg("tipc_link_create(): tolerance = %u,cont intv = %u, abort_limit = %u\n",
 482             l_ptr->tolerance, l_ptr->continuity_interval, l_ptr->abort_limit);
 483
 484         return l_ptr;
 485 }
 486
 487 /**
 488  * tipc_link_delete - delete a link
 489  * @l_ptr: pointer to link
 490  *
 491  * Note: 'tipc_net_lock' is write_locked, bearer is locked.
 492  * This routine must not grab the node lock until after link timer cancellation
 493  * to avoid a potential deadlock situation.
 494  */
 495
 496 void tipc_link_delete(struct link *l_ptr)
 497 {
 498         if (!l_ptr) {
 499                 err("Attempt to delete non-existent link\n");
 500                 return;
 501         }
 502
 503         dbg("tipc_link_delete()\n");
 504
 505         k_cancel_timer(&l_ptr->timer);
 506
 507         tipc_node_lock(l_ptr->owner);
 508         tipc_link_reset(l_ptr);
 509         tipc_node_detach_link(l_ptr->owner, l_ptr);
 510         tipc_link_stop(l_ptr);
 511         list_del_init(&l_ptr->link_list);
 512         if (LINK_LOG_BUF_SIZE)
 513                 kfree(l_ptr->print_buf.buf);
 514         tipc_node_unlock(l_ptr->owner);
 515         k_term_timer(&l_ptr->timer);
 516         kfree(l_ptr);
 517 }
 518
 519 void tipc_link_start(struct link *l_ptr)
 520 {
 521         dbg("tipc_link_start %x\n", l_ptr);
 522         link_state_event(l_ptr, STARTING_EVT);
 523 }
 524
 525 /**
 526  * link_schedule_port - schedule port for deferred sending
 527  * @l_ptr: pointer to link
 528  * @origport: reference to sending port
 529  * @sz: amount of data to be sent
 530  *
 531  * Schedules port for renewed sending of messages after link congestion
 532  * has abated.
 533  */
 534
 535 static int link_schedule_port(struct link *l_ptr, u32 origport, u32 sz)
 536 {
 537         struct port *p_ptr;
 538
 539         spin_lock_bh(&tipc_port_list_lock);
 540         p_ptr = tipc_port_lock(origport);
 541         if (p_ptr) {
 542                 if (!p_ptr->wakeup)
 543                         goto exit;
 544                 if (!list_empty(&p_ptr->wait_list))
 545                         goto exit;
 546                 p_ptr->congested_link = l_ptr;
 547                 p_ptr->publ.congested = 1;
 548                 p_ptr->waiting_pkts = 1 + ((sz - 1) / link_max_pkt(l_ptr));
 549                 list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
 550                 l_ptr->stats.link_congs++;
 551 exit:
 552                 tipc_port_unlock(p_ptr);
 553         }
 554         spin_unlock_bh(&tipc_port_list_lock);
 555         return -ELINKCONG;
 556 }
 557
 558 void tipc_link_wakeup_ports(struct link *l_ptr, int all)
 559 {
 560         struct port *p_ptr;
 561         struct port *temp_p_ptr;
 562         int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;
 563
 564         if (all)
 565                 win = 100000;
 566         if (win <= 0)
 567                 return;
 568         if (!spin_trylock_bh(&tipc_port_list_lock))
 569                 return;
 570         if (link_congested(l_ptr))
 571                 goto exit;
 572         list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
 573                                  wait_list) {
 574                 if (win <= 0)
 575                         break;
 576                 list_del_init(&p_ptr->wait_list);
 577                 p_ptr->congested_link = NULL;
 578                 spin_lock_bh(p_ptr->publ.lock);
 579                 p_ptr->publ.congested = 0;
 580                 p_ptr->wakeup(&p_ptr->publ);
 581                 win -= p_ptr->waiting_pkts;
 582                 spin_unlock_bh(p_ptr->publ.lock);
 583         }
 584
 585 exit:
 586         spin_unlock_bh(&tipc_port_list_lock);
 587 }
 588
 589 /**
 590  * link_release_outqueue - purge link's outbound message queue
 591  * @l_ptr: pointer to link
 592  */
 593
 594 static void link_release_outqueue(struct link *l_ptr)
 595 {
 596         struct sk_buff *buf = l_ptr->first_out;
 597         struct sk_buff *next;
 598
 599         while (buf) {
 600                 next = buf->next;
 601                 buf_discard(buf);
 602                 buf = next;
 603         }
 604         l_ptr->first_out = NULL;
 605         l_ptr->out_queue_size = 0;
 606 }
 607
 608 /**
 609  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 610  * @l_ptr: pointer to link
 611  */
 612
 613 void tipc_link_reset_fragments(struct link *l_ptr)
 614 {
 615         struct sk_buff *buf = l_ptr->defragm_buf;
 616         struct sk_buff *next;
 617
 618         while (buf) {
 619                 next = buf->next;
 620                 buf_discard(buf);
 621                 buf = next;
 622         }
 623         l_ptr->defragm_buf = NULL;
 624 }
 625
 626 /**
 627  * tipc_link_stop - purge all inbound and outbound messages associated with link
 628  * @l_ptr: pointer to link
 629  */
 630
 631 void tipc_link_stop(struct link *l_ptr)
 632 {
 633         struct sk_buff *buf;
 634         struct sk_buff *next;
 635
 636         buf = l_ptr->oldest_deferred_in;
 637         while (buf) {
 638                 next = buf->next;
 639                 buf_discard(buf);
 640                 buf = next;
 641         }
 642
 643         buf = l_ptr->first_out;
 644         while (buf) {
 645                 next = buf->next;
 646                 buf_discard(buf);
 647                 buf = next;
 648         }
 649
 650         tipc_link_reset_fragments(l_ptr);
 651
 652         buf_discard(l_ptr->proto_msg_queue);
 653         l_ptr->proto_msg_queue = NULL;
 654 }
 655
 656 #if 0
 657
 658 /* LINK EVENT CODE IS NOT SUPPORTED AT PRESENT */
 659
 660 static void link_recv_event(struct link_event *ev)
 661 {
 662         ev->fcn(ev->addr, ev->name, ev->up);
 663         kfree(ev);
 664 }
 665
 666 static void link_send_event(void (*fcn)(u32 a, char *n, int up),
 667                             struct link *l_ptr, int up)
 668 {
 669         struct link_event *ev;
 670
 671         ev = kmalloc(sizeof(*ev), GFP_ATOMIC);
 672         if (!ev) {
 673                 warn("Link event allocation failure\n");
 674                 return;
 675         }
 676         ev->addr = l_ptr->addr;
 677         ev->up = up;
 678         ev->fcn = fcn;
 679         memcpy(ev->name, l_ptr->name, TIPC_MAX_LINK_NAME);
 680         tipc_k_signal((Handler)link_recv_event, (unsigned long)ev);
 681 }
 682
 683 #else
 684
 685 #define link_send_event(fcn, l_ptr, up) do { } while (0)
 686
 687 #endif
 688
 689 void tipc_link_reset(struct link *l_ptr)
 690 {
 691         struct sk_buff *buf;
 692         u32 prev_state = l_ptr->state;
 693         u32 checkpoint = l_ptr->next_in_no;
 694         int was_active_link = tipc_link_is_active(l_ptr);
 695
 696         msg_set_session(l_ptr->pmsg, msg_session(l_ptr->pmsg) + 1);
 697
 698         /* Link is down, accept any session: */
 699         l_ptr->peer_session = 0;
 700
 701         /* Prepare for max packet size negotiation */
 702         link_init_max_pkt(l_ptr);
 703
 704         l_ptr->state = RESET_UNKNOWN;
 705         dbg_link_state("Resetting Link\n");
 706
 707         if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
 708                 return;
 709
 710         tipc_node_link_down(l_ptr->owner, l_ptr);
 711         tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
 712 #if 0
 713         tipc_printf(TIPC_CONS, "\nReset link <%s>\n", l_ptr->name);
 714         dbg_link_dump();
 715 #endif
 716         if (was_active_link && tipc_node_has_active_links(l_ptr->owner) &&
 717             l_ptr->owner->permit_changeover) {
 718                 l_ptr->reset_checkpoint = checkpoint;
 719                 l_ptr->exp_msg_count = START_CHANGEOVER;
 720         }
 721
 722         /* Clean up all queues: */
 723
 724         link_release_outqueue(l_ptr);
 725         buf_discard(l_ptr->proto_msg_queue);
 726         l_ptr->proto_msg_queue = NULL;
 727         buf = l_ptr->oldest_deferred_in;
 728         while (buf) {
 729                 struct sk_buff *next = buf->next;
 730                 buf_discard(buf);
 731                 buf = next;
 732         }
 733         if (!list_empty(&l_ptr->waiting_ports))
 734                 tipc_link_wakeup_ports(l_ptr, 1);
 735
 736         l_ptr->retransm_queue_head = 0;
 737         l_ptr->retransm_queue_size = 0;
 738         l_ptr->last_out = NULL;
 739         l_ptr->first_out = NULL;
 740         l_ptr->next_out = NULL;
 741         l_ptr->unacked_window = 0;
 742         l_ptr->checkpoint = 1;
 743         l_ptr->next_out_no = 1;
 744         l_ptr->deferred_inqueue_sz = 0;
 745         l_ptr->oldest_deferred_in = NULL;
 746         l_ptr->newest_deferred_in = NULL;
 747         l_ptr->fsm_msg_cnt = 0;
 748         l_ptr->stale_count = 0;
 749         link_reset_statistics(l_ptr);
 750
 751         link_send_event(tipc_cfg_link_event, l_ptr, 0);
 752         if (!in_own_cluster(l_ptr->addr))
 753                 link_send_event(tipc_disc_link_event, l_ptr, 0);
 754 }
 755
 756
 757 static void link_activate(struct link *l_ptr)
 758 {
 759         l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
 760         tipc_node_link_up(l_ptr->owner, l_ptr);
 761         tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
 762         link_send_event(tipc_cfg_link_event, l_ptr, 1);
 763         if (!in_own_cluster(l_ptr->addr))
 764                 link_send_event(tipc_disc_link_event, l_ptr, 1);
 765 }
 766
 767 /**
 768  * link_state_event - link finite state machine
 769  * @l_ptr: pointer to link
 770  * @event: state machine event to process
 771  */
 772
 773 static void link_state_event(struct link *l_ptr, unsigned event)
 774 {
 775         struct link *other;
 776         u32 cont_intv = l_ptr->continuity_interval;
 777
 778         if (!l_ptr->started && (event != STARTING_EVT))
 779                 return;         /* Not yet. */
 780
 781         if (link_blocked(l_ptr)) {
 782                 if (event == TIMEOUT_EVT) {
 783                         link_set_timer(l_ptr, cont_intv);
 784                 }
 785                 return;   /* Changeover going on */
 786         }
 787         dbg_link("STATE_EV: <%s> ", l_ptr->name);
 788
 789         switch (l_ptr->state) {
 790         case WORKING_WORKING:
 791                 dbg_link("WW/");
 792                 switch (event) {
 793                 case TRAFFIC_MSG_EVT:
 794                         dbg_link("TRF-");
 795                         /* fall through */
 796                 case ACTIVATE_MSG:
 797                         dbg_link("ACT\n");
 798                         break;
 799                 case TIMEOUT_EVT:
 800                         dbg_link("TIM ");
 801                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 802                                 l_ptr->checkpoint = l_ptr->next_in_no;
 803                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 804                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 805                                                                  0, 0, 0, 0, 0);
 806                                         l_ptr->fsm_msg_cnt++;
 807                                 } else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
 808                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 809                                                                  1, 0, 0, 0, 0);
 810                                         l_ptr->fsm_msg_cnt++;
 811                                 }
 812                                 link_set_timer(l_ptr, cont_intv);
 813                                 break;
 814                         }
 815                         dbg_link(" -> WU\n");
 816                         l_ptr->state = WORKING_UNKNOWN;
 817                         l_ptr->fsm_msg_cnt = 0;
 818                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 819                         l_ptr->fsm_msg_cnt++;
 820                         link_set_timer(l_ptr, cont_intv / 4);
 821                         break;
 822                 case RESET_MSG:
 823                         dbg_link("RES -> RR\n");
 824                         info("Resetting link <%s>, requested by peer\n",
 825                              l_ptr->name);
 826                         tipc_link_reset(l_ptr);
 827                         l_ptr->state = RESET_RESET;
 828                         l_ptr->fsm_msg_cnt = 0;
 829                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 830                         l_ptr->fsm_msg_cnt++;
 831                         link_set_timer(l_ptr, cont_intv);
 832                         break;
 833                 default:
 834                         err("Unknown link event %u in WW state\n", event);
 835                 }
 836                 break;
 837         case WORKING_UNKNOWN:
 838                 dbg_link("WU/");
 839                 switch (event) {
 840                 case TRAFFIC_MSG_EVT:
 841                         dbg_link("TRF-");
 842                 case ACTIVATE_MSG:
 843                         dbg_link("ACT -> WW\n");
 844                         l_ptr->state = WORKING_WORKING;
 845                         l_ptr->fsm_msg_cnt = 0;
 846                         link_set_timer(l_ptr, cont_intv);
 847                         break;
 848                 case RESET_MSG:
 849                         dbg_link("RES -> RR\n");
 850                         info("Resetting link <%s>, requested by peer "
 851                              "while probing\n", l_ptr->name);
 852                         tipc_link_reset(l_ptr);
 853                         l_ptr->state = RESET_RESET;
 854                         l_ptr->fsm_msg_cnt = 0;
 855                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 856                         l_ptr->fsm_msg_cnt++;
 857                         link_set_timer(l_ptr, cont_intv);
 858                         break;
 859                 case TIMEOUT_EVT:
 860                         dbg_link("TIM ");
 861                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 862                                 dbg_link("-> WW \n");
 863                                 l_ptr->state = WORKING_WORKING;
 864                                 l_ptr->fsm_msg_cnt = 0;
 865                                 l_ptr->checkpoint = l_ptr->next_in_no;
 866                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 867                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 868                                                                  0, 0, 0, 0, 0);
 869                                         l_ptr->fsm_msg_cnt++;
 870                                 }
 871                                 link_set_timer(l_ptr, cont_intv);
 872                         } else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
 873                                 dbg_link("Probing %u/%u,timer = %u ms)\n",
 874                                          l_ptr->fsm_msg_cnt, l_ptr->abort_limit,
 875                                          cont_intv / 4);
 876                                 tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 877                                                          1, 0, 0, 0, 0);
 878                                 l_ptr->fsm_msg_cnt++;
 879                                 link_set_timer(l_ptr, cont_intv / 4);
 880                         } else {        /* Link has failed */
 881                                 dbg_link("-> RU (%u probes unanswered)\n",
 882                                          l_ptr->fsm_msg_cnt);
 883                                 warn("Resetting link <%s>, peer not responding\n",
 884                                      l_ptr->name);
 885                                 tipc_link_reset(l_ptr);
 886                                 l_ptr->state = RESET_UNKNOWN;
 887                                 l_ptr->fsm_msg_cnt = 0;
 888                                 tipc_link_send_proto_msg(l_ptr, RESET_MSG,
 889                                                          0, 0, 0, 0, 0);
 890                                 l_ptr->fsm_msg_cnt++;
 891                                 link_set_timer(l_ptr, cont_intv);
 892                         }
 893                         break;
 894                 default:
 895                         err("Unknown link event %u in WU state\n", event);
 896                 }
 897                 break;
 898         case RESET_UNKNOWN:
 899                 dbg_link("RU/");
 900                 switch (event) {
 901                 case TRAFFIC_MSG_EVT:
 902                         dbg_link("TRF-\n");
 903                         break;
 904                 case ACTIVATE_MSG:
 905                         other = l_ptr->owner->active_links[0];
 906                         if (other && link_working_unknown(other)) {
 907                                 dbg_link("ACT\n");
 908                                 break;
 909                         }
 910                         dbg_link("ACT -> WW\n");
 911                         l_ptr->state = WORKING_WORKING;
 912                         l_ptr->fsm_msg_cnt = 0;
 913                         link_activate(l_ptr);
 914                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 915                         l_ptr->fsm_msg_cnt++;
 916                         link_set_timer(l_ptr, cont_intv);
 917                         break;
 918                 case RESET_MSG:
 919                         dbg_link("RES \n");
 920                         dbg_link(" -> RR\n");
 921                         l_ptr->state = RESET_RESET;
 922                         l_ptr->fsm_msg_cnt = 0;
 923                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
 924                         l_ptr->fsm_msg_cnt++;
 925                         link_set_timer(l_ptr, cont_intv);
 926                         break;
 927                 case STARTING_EVT:
 928                         dbg_link("START-");
 929                         l_ptr->started = 1;
 930                         /* fall through */
 931                 case TIMEOUT_EVT:
 932                         dbg_link("TIM \n");
 933                         tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
 934                         l_ptr->fsm_msg_cnt++;
 935                         link_set_timer(l_ptr, cont_intv);
 936                         break;
 937                 default:
 938                         err("Unknown link event %u in RU state\n", event);
 939                 }
 940                 break;
 941         case RESET_RESET:
 942                 dbg_link("RR/ ");
 943                 switch (event) {
 944                 case TRAFFIC_MSG_EVT:
 945                         dbg_link("TRF-");
 946                         /* fall through */
 947                 case ACTIVATE_MSG:
 948                         other = l_ptr->owner->active_links[0];
 949                         if (other && link_working_unknown(other)) {
 950                                 dbg_link("ACT\n");
 951                                 break;
 952                         }
 953                         dbg_link("ACT -> WW\n");
 954                         l_ptr->state = WORKING_WORKING;
 955                         l_ptr->fsm_msg_cnt = 0;
 956                         link_activate(l_ptr);
 957                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 958                         l_ptr->fsm_msg_cnt++;
 959                         link_set_timer(l_ptr, cont_intv);
 960                         break;
 961                 case RESET_MSG:
 962                         dbg_link("RES\n");
 963                         break;
 964                 case TIMEOUT_EVT:
 965                         dbg_link("TIM\n");
 966                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 967                         l_ptr->fsm_msg_cnt++;
 968                         link_set_timer(l_ptr, cont_intv);
 969                         dbg_link("fsm_msg_cnt %u\n", l_ptr->fsm_msg_cnt);
 970                         break;
 971                 default:
 972                         err("Unknown link event %u in RR state\n", event);
 973                 }
 974                 break;
 975         default:
 976                 err("Unknown link state %u/%u\n", l_ptr->state, event);
 977         }
 978 }
 979
 980 /*
 981  * link_bundle_buf(): Append contents of a buffer to
 982  * the tail of an existing one.
 983  */
 984
 985 static int link_bundle_buf(struct link *l_ptr,
 986                            struct sk_buff *bundler,
 987                            struct sk_buff *buf)
 988 {
 989         struct tipc_msg *bundler_msg = buf_msg(bundler);
 990         struct tipc_msg *msg = buf_msg(buf);
 991         u32 size = msg_size(msg);
 992         u32 bundle_size = msg_size(bundler_msg);
 993         u32 to_pos = align(bundle_size);
 994         u32 pad = to_pos - bundle_size;
 995
 996         if (msg_user(bundler_msg) != MSG_BUNDLER)
 997                 return 0;
 998         if (msg_type(bundler_msg) != OPEN_MSG)
 999                 return 0;
1000         if (skb_tailroom(bundler) < (pad + size))
1001                 return 0;
1002         if (link_max_pkt(l_ptr) < (to_pos + size))
1003                 return 0;
1004
1005         skb_put(bundler, pad + size);
1006         skb_copy_to_linear_data_offset(bundler, to_pos, buf->data, size);
1007         msg_set_size(bundler_msg, to_pos + size);
1008         msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
1009         dbg("Packed msg # %u(%u octets) into pos %u in buf(#%u)\n",
1010             msg_msgcnt(bundler_msg), size, to_pos, msg_seqno(bundler_msg));
1011         msg_dbg(msg, "PACKD:");
1012         buf_discard(buf);
1013         l_ptr->stats.sent_bundled++;
1014         return 1;
1015 }
1016
1017 static void link_add_to_outqueue(struct link *l_ptr,
1018                                  struct sk_buff *buf,
1019                                  struct tipc_msg *msg)
1020 {
1021         u32 ack = mod(l_ptr->next_in_no - 1);
1022         u32 seqno = mod(l_ptr->next_out_no++);
1023
1024         msg_set_word(msg, 2, ((ack << 16) | seqno));
1025         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1026         buf->next = NULL;
1027         if (l_ptr->first_out) {
1028                 l_ptr->last_out->next = buf;
1029                 l_ptr->last_out = buf;
1030         } else
1031                 l_ptr->first_out = l_ptr->last_out = buf;
1032         l_ptr->out_queue_size++;
1033 }
1034
1035 /*
1036  * tipc_link_send_buf() is the 'full path' for messages, called from
1037  * inside TIPC when the 'fast path' in tipc_send_buf
1038  * has failed, and from link_send()
1039  */
1040
1041 int tipc_link_send_buf(struct link *l_ptr, struct sk_buff *buf)
1042 {
1043         struct tipc_msg *msg = buf_msg(buf);
1044         u32 size = msg_size(msg);
1045         u32 dsz = msg_data_sz(msg);
1046         u32 queue_size = l_ptr->out_queue_size;
1047         u32 imp = msg_tot_importance(msg);
1048         u32 queue_limit = l_ptr->queue_limit[imp];
1049         u32 max_packet = link_max_pkt(l_ptr);
1050
1051         msg_set_prevnode(msg, tipc_own_addr);   /* If routed message */
1052
1053         /* Match msg importance against queue limits: */
1054
1055         if (unlikely(queue_size >= queue_limit)) {
1056                 if (imp <= TIPC_CRITICAL_IMPORTANCE) {
1057                         return link_schedule_port(l_ptr, msg_origport(msg),
1058                                                   size);
1059                 }
1060                 msg_dbg(msg, "TIPC: Congestion, throwing away\n");
1061                 buf_discard(buf);
1062                 if (imp > CONN_MANAGER) {
1063                         warn("Resetting link <%s>, send queue full", l_ptr->name);
1064                         tipc_link_reset(l_ptr);
1065                 }
1066                 return dsz;
1067         }
1068
1069         /* Fragmentation needed ? */
1070
1071         if (size > max_packet)
1072                 return tipc_link_send_long_buf(l_ptr, buf);
1073
1074         /* Packet can be queued or sent: */
1075
1076         if (queue_size > l_ptr->stats.max_queue_sz)
1077                 l_ptr->stats.max_queue_sz = queue_size;
1078
1079         if (likely(!tipc_bearer_congested(l_ptr->b_ptr, l_ptr) &&
1080                    !link_congested(l_ptr))) {
1081                 link_add_to_outqueue(l_ptr, buf, msg);
1082
1083                 if (likely(tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr))) {
1084                         l_ptr->unacked_window = 0;
1085                 } else {
1086                         tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1087                         l_ptr->stats.bearer_congs++;
1088                         l_ptr->next_out = buf;
1089                 }
1090                 return dsz;
1091         }
1092         /* Congestion: can message be bundled ?: */
1093
1094         if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
1095             (msg_user(msg) != MSG_FRAGMENTER)) {
1096
1097                 /* Try adding message to an existing bundle */
1098
1099                 if (l_ptr->next_out &&
1100                     link_bundle_buf(l_ptr, l_ptr->last_out, buf)) {
1101                         tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
1102                         return dsz;
1103                 }
1104
1105                 /* Try creating a new bundle */
1106
1107                 if (size <= max_packet * 2 / 3) {
1108                         struct sk_buff *bundler = buf_acquire(max_packet);
1109                         struct tipc_msg bundler_hdr;
1110
1111                         if (bundler) {
1112                                 msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
1113                                          TIPC_OK, INT_H_SIZE, l_ptr->addr);
1114                                 skb_copy_to_linear_data(bundler, &bundler_hdr,
1115                                                         INT_H_SIZE);
1116                                 skb_trim(bundler, INT_H_SIZE);
1117                                 link_bundle_buf(l_ptr, bundler, buf);
1118                                 buf = bundler;
1119                                 msg = buf_msg(buf);
1120                                 l_ptr->stats.sent_bundles++;
1121                         }
1122                 }
1123         }
1124         if (!l_ptr->next_out)
1125                 l_ptr->next_out = buf;
1126         link_add_to_outqueue(l_ptr, buf, msg);
1127         tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
1128         return dsz;
1129 }
1130
1131 /*
1132  * tipc_link_send(): same as tipc_link_send_buf(), but the link to use has
1133  * not been selected yet, and the the owner node is not locked
1134  * Called by TIPC internal users, e.g. the name distributor
1135  */
1136
1137 int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector)
1138 {
1139         struct link *l_ptr;
1140         struct node *n_ptr;
1141         int res = -ELINKCONG;
1142
1143         read_lock_bh(&tipc_net_lock);
1144         n_ptr = tipc_node_select(dest, selector);
1145         if (n_ptr) {
1146                 tipc_node_lock(n_ptr);
1147                 l_ptr = n_ptr->active_links[selector & 1];
1148                 if (l_ptr) {
1149                         dbg("tipc_link_send: found link %x for dest %x\n", l_ptr, dest);
1150                         res = tipc_link_send_buf(l_ptr, buf);
1151                 } else {
1152                         dbg("Attempt to send msg to unreachable node:\n");
1153                         msg_dbg(buf_msg(buf),">>>");
1154                         buf_discard(buf);
1155                 }
1156                 tipc_node_unlock(n_ptr);
1157         } else {
1158                 dbg("Attempt to send msg to unknown node:\n");
1159                 msg_dbg(buf_msg(buf),">>>");
1160                 buf_discard(buf);
1161         }
1162         read_unlock_bh(&tipc_net_lock);
1163         return res;
1164 }
1165
1166 /*
1167  * link_send_buf_fast: Entry for data messages where the
1168  * destination link is known and the header is complete,
1169  * inclusive total message length. Very time critical.
1170  * Link is locked. Returns user data length.
1171  */
1172
1173 static int link_send_buf_fast(struct link *l_ptr, struct sk_buff *buf,
1174                               u32 *used_max_pkt)
1175 {
1176         struct tipc_msg *msg = buf_msg(buf);
1177         int res = msg_data_sz(msg);
1178
1179         if (likely(!link_congested(l_ptr))) {
1180                 if (likely(msg_size(msg) <= link_max_pkt(l_ptr))) {
1181                         if (likely(list_empty(&l_ptr->b_ptr->cong_links))) {
1182                                 link_add_to_outqueue(l_ptr, buf, msg);
1183                                 if (likely(tipc_bearer_send(l_ptr->b_ptr, buf,
1184                                                             &l_ptr->media_addr))) {
1185                                         l_ptr->unacked_window = 0;
1186                                         msg_dbg(msg,"SENT_FAST:");
1187                                         return res;
1188                                 }
1189                                 dbg("failed sent fast...\n");
1190                                 tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1191                                 l_ptr->stats.bearer_congs++;
1192                                 l_ptr->next_out = buf;
1193                                 return res;
1194                         }
1195                 }
1196                 else
1197                         *used_max_pkt = link_max_pkt(l_ptr);
1198         }
1199         return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
1200 }
1201
1202 /*
1203  * tipc_send_buf_fast: Entry for data messages where the
1204  * destination node is known and the header is complete,
1205  * inclusive total message length.
1206  * Returns user data length.
1207  */
1208 int tipc_send_buf_fast(struct sk_buff *buf, u32 destnode)
1209 {
1210         struct link *l_ptr;
1211         struct node *n_ptr;
1212         int res;
1213         u32 selector = msg_origport(buf_msg(buf)) & 1;
1214         u32 dummy;
1215
1216         if (destnode == tipc_own_addr)
1217                 return tipc_port_recv_msg(buf);
1218
1219         read_lock_bh(&tipc_net_lock);
1220         n_ptr = tipc_node_select(destnode, selector);
1221         if (likely(n_ptr)) {
1222                 tipc_node_lock(n_ptr);
1223                 l_ptr = n_ptr->active_links[selector];
1224                 dbg("send_fast: buf %x selected %x, destnode = %x\n",
1225                     buf, l_ptr, destnode);
1226                 if (likely(l_ptr)) {
1227                         res = link_send_buf_fast(l_ptr, buf, &dummy);
1228                         tipc_node_unlock(n_ptr);
1229                         read_unlock_bh(&tipc_net_lock);
1230                         return res;
1231                 }
1232                 tipc_node_unlock(n_ptr);
1233         }
1234         read_unlock_bh(&tipc_net_lock);
1235         res = msg_data_sz(buf_msg(buf));
1236         tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1237         return res;
1238 }
1239
1240
1241 /*
1242  * tipc_link_send_sections_fast: Entry for messages where the
1243  * destination processor is known and the header is complete,
1244  * except for total message length.
1245  * Returns user data length or errno.
1246  */
1247 int tipc_link_send_sections_fast(struct port *sender,
1248                                  struct iovec const *msg_sect,
1249                                  const u32 num_sect,
1250                                  u32 destaddr)
1251 {
1252         struct tipc_msg *hdr = &sender->publ.phdr;
1253         struct link *l_ptr;
1254         struct sk_buff *buf;
1255         struct node *node;
1256         int res;
1257         u32 selector = msg_origport(hdr) & 1;
1258
1259 again:
1260         /*
1261          * Try building message using port's max_pkt hint.
1262          * (Must not hold any locks while building message.)
1263          */
1264
1265         res = msg_build(hdr, msg_sect, num_sect, sender->publ.max_pkt,
1266                         !sender->user_port, &buf);
1267
1268         read_lock_bh(&tipc_net_lock);
1269         node = tipc_node_select(destaddr, selector);
1270         if (likely(node)) {
1271                 tipc_node_lock(node);
1272                 l_ptr = node->active_links[selector];
1273                 if (likely(l_ptr)) {
1274                         if (likely(buf)) {
1275                                 res = link_send_buf_fast(l_ptr, buf,
1276                                                          &sender->publ.max_pkt);
1277                                 if (unlikely(res < 0))
1278                                         buf_discard(buf);
1279 exit:
1280                                 tipc_node_unlock(node);
1281                                 read_unlock_bh(&tipc_net_lock);
1282                                 return res;
1283                         }
1284
1285                         /* Exit if build request was invalid */
1286
1287                         if (unlikely(res < 0))
1288                                 goto exit;
1289
1290                         /* Exit if link (or bearer) is congested */
1291
1292                         if (link_congested(l_ptr) ||
1293                             !list_empty(&l_ptr->b_ptr->cong_links)) {
1294                                 res = link_schedule_port(l_ptr,
1295                                                          sender->publ.ref, res);
1296                                 goto exit;
1297                         }
1298
1299                         /*
1300                          * Message size exceeds max_pkt hint; update hint,
1301                          * then re-try fast path or fragment the message
1302                          */
1303
1304                         sender->publ.max_pkt = link_max_pkt(l_ptr);
1305                         tipc_node_unlock(node);
1306                         read_unlock_bh(&tipc_net_lock);
1307
1308
1309                         if ((msg_hdr_sz(hdr) + res) <= sender->publ.max_pkt)
1310                                 goto again;
1311
1312                         return link_send_sections_long(sender, msg_sect,
1313                                                        num_sect, destaddr);
1314                 }
1315                 tipc_node_unlock(node);
1316         }
1317         read_unlock_bh(&tipc_net_lock);
1318
1319         /* Couldn't find a link to the destination node */
1320
1321         if (buf)
1322                 return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1323         if (res >= 0)
1324                 return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1325                                                  TIPC_ERR_NO_NODE);
1326         return res;
1327 }
1328
1329 /*
1330  * link_send_sections_long(): Entry for long messages where the
1331  * destination node is known and the header is complete,
1332  * inclusive total message length.
1333  * Link and bearer congestion status have been checked to be ok,
1334  * and are ignored if they change.
1335  *
1336  * Note that fragments do not use the full link MTU so that they won't have
1337  * to undergo refragmentation if link changeover causes them to be sent
1338  * over another link with an additional tunnel header added as prefix.
1339  * (Refragmentation will still occur if the other link has a smaller MTU.)
1340  *
1341  * Returns user data length or errno.
1342  */
1343 static int link_send_sections_long(struct port *sender,
1344                                    struct iovec const *msg_sect,
1345                                    u32 num_sect,
1346                                    u32 destaddr)
1347 {
1348         struct link *l_ptr;
1349         struct node *node;
1350         struct tipc_msg *hdr = &sender->publ.phdr;
1351         u32 dsz = msg_data_sz(hdr);
1352         u32 max_pkt,fragm_sz,rest;
1353         struct tipc_msg fragm_hdr;
1354         struct sk_buff *buf,*buf_chain,*prev;
1355         u32 fragm_crs,fragm_rest,hsz,sect_rest;
1356         const unchar *sect_crs;
1357         int curr_sect;
1358         u32 fragm_no;
1359
1360 again:
1361         fragm_no = 1;
1362         max_pkt = sender->publ.max_pkt - INT_H_SIZE;
1363                 /* leave room for tunnel header in case of link changeover */
1364         fragm_sz = max_pkt - INT_H_SIZE;
1365                 /* leave room for fragmentation header in each fragment */
1366         rest = dsz;
1367         fragm_crs = 0;
1368         fragm_rest = 0;
1369         sect_rest = 0;
1370         sect_crs = NULL;
1371         curr_sect = -1;
1372
1373         /* Prepare reusable fragment header: */
1374
1375         msg_dbg(hdr, ">FRAGMENTING>");
1376         msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
1377                  TIPC_OK, INT_H_SIZE, msg_destnode(hdr));
1378         msg_set_link_selector(&fragm_hdr, sender->publ.ref);
1379         msg_set_size(&fragm_hdr, max_pkt);
1380         msg_set_fragm_no(&fragm_hdr, 1);
1381
1382         /* Prepare header of first fragment: */
1383
1384         buf_chain = buf = buf_acquire(max_pkt);
1385         if (!buf)
1386                 return -ENOMEM;
1387         buf->next = NULL;
1388         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1389         hsz = msg_hdr_sz(hdr);
1390         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, hdr, hsz);
1391         msg_dbg(buf_msg(buf), ">BUILD>");
1392
1393         /* Chop up message: */
1394
1395         fragm_crs = INT_H_SIZE + hsz;
1396         fragm_rest = fragm_sz - hsz;
1397
1398         do {            /* For all sections */
1399                 u32 sz;
1400
1401                 if (!sect_rest) {
1402                         sect_rest = msg_sect[++curr_sect].iov_len;
1403                         sect_crs = (const unchar *)msg_sect[curr_sect].iov_base;
1404                 }
1405
1406                 if (sect_rest < fragm_rest)
1407                         sz = sect_rest;
1408                 else
1409                         sz = fragm_rest;
1410
1411                 if (likely(!sender->user_port)) {
1412                         if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
1413 error:
1414                                 for (; buf_chain; buf_chain = buf) {
1415                                         buf = buf_chain->next;
1416                                         buf_discard(buf_chain);
1417                                 }
1418                                 return -EFAULT;
1419                         }
1420                 } else
1421                         skb_copy_to_linear_data_offset(buf, fragm_crs,
1422                                                        sect_crs, sz);
1423                 sect_crs += sz;
1424                 sect_rest -= sz;
1425                 fragm_crs += sz;
1426                 fragm_rest -= sz;
1427                 rest -= sz;
1428
1429                 if (!fragm_rest && rest) {
1430
1431                         /* Initiate new fragment: */
1432                         if (rest <= fragm_sz) {
1433                                 fragm_sz = rest;
1434                                 msg_set_type(&fragm_hdr,LAST_FRAGMENT);
1435                         } else {
1436                                 msg_set_type(&fragm_hdr, FRAGMENT);
1437                         }
1438                         msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
1439                         msg_set_fragm_no(&fragm_hdr, ++fragm_no);
1440                         prev = buf;
1441                         buf = buf_acquire(fragm_sz + INT_H_SIZE);
1442                         if (!buf)
1443                                 goto error;
1444
1445                         buf->next = NULL;
1446                         prev->next = buf;
1447                         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1448                         fragm_crs = INT_H_SIZE;
1449                         fragm_rest = fragm_sz;
1450                         msg_dbg(buf_msg(buf),"  >BUILD>");
1451                 }
1452         }
1453         while (rest > 0);
1454
1455         /*
1456          * Now we have a buffer chain. Select a link and check
1457          * that packet size is still OK
1458          */
1459         node = tipc_node_select(destaddr, sender->publ.ref & 1);
1460         if (likely(node)) {
1461                 tipc_node_lock(node);
1462                 l_ptr = node->active_links[sender->publ.ref & 1];
1463                 if (!l_ptr) {
1464                         tipc_node_unlock(node);
1465                         goto reject;
1466                 }
1467                 if (link_max_pkt(l_ptr) < max_pkt) {
1468                         sender->publ.max_pkt = link_max_pkt(l_ptr);
1469                         tipc_node_unlock(node);
1470                         for (; buf_chain; buf_chain = buf) {
1471                                 buf = buf_chain->next;
1472                                 buf_discard(buf_chain);
1473                         }
1474                         goto again;
1475                 }
1476         } else {
1477 reject:
1478                 for (; buf_chain; buf_chain = buf) {
1479                         buf = buf_chain->next;
1480                         buf_discard(buf_chain);
1481                 }
1482                 return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1483                                                  TIPC_ERR_NO_NODE);
1484         }
1485
1486         /* Append whole chain to send queue: */
1487
1488         buf = buf_chain;
1489         l_ptr->long_msg_seq_no = mod(l_ptr->long_msg_seq_no + 1);
1490         if (!l_ptr->next_out)
1491                 l_ptr->next_out = buf_chain;
1492         l_ptr->stats.sent_fragmented++;
1493         while (buf) {
1494                 struct sk_buff *next = buf->next;
1495                 struct tipc_msg *msg = buf_msg(buf);
1496
1497                 l_ptr->stats.sent_fragments++;
1498                 msg_set_long_msgno(msg, l_ptr->long_msg_seq_no);
1499                 link_add_to_outqueue(l_ptr, buf, msg);
1500                 msg_dbg(msg, ">ADD>");
1501                 buf = next;
1502         }
1503
1504         /* Send it, if possible: */
1505
1506         tipc_link_push_queue(l_ptr);
1507         tipc_node_unlock(node);
1508         return dsz;
1509 }
1510
1511 /*
1512  * tipc_link_push_packet: Push one unsent packet to the media
1513  */
1514 u32 tipc_link_push_packet(struct link *l_ptr)
1515 {
1516         struct sk_buff *buf = l_ptr->first_out;
1517         u32 r_q_size = l_ptr->retransm_queue_size;
1518         u32 r_q_head = l_ptr->retransm_queue_head;
1519
1520         /* Step to position where retransmission failed, if any,    */
1521         /* consider that buffers may have been released in meantime */
1522
1523         if (r_q_size && buf) {
1524                 u32 last = lesser(mod(r_q_head + r_q_size),
1525                                   link_last_sent(l_ptr));
1526                 u32 first = msg_seqno(buf_msg(buf));
1527
1528                 while (buf && less(first, r_q_head)) {
1529                         first = mod(first + 1);
1530                         buf = buf->next;
1531                 }
1532                 l_ptr->retransm_queue_head = r_q_head = first;
1533                 l_ptr->retransm_queue_size = r_q_size = mod(last - first);
1534         }
1535
1536         /* Continue retransmission now, if there is anything: */
1537
1538         if (r_q_size && buf && !skb_cloned(buf)) {
1539                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1540                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1541                 if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1542                         msg_dbg(buf_msg(buf), ">DEF-RETR>");
1543                         l_ptr->retransm_queue_head = mod(++r_q_head);
1544                         l_ptr->retransm_queue_size = --r_q_size;
1545                         l_ptr->stats.retransmitted++;
1546                         return TIPC_OK;
1547                 } else {
1548                         l_ptr->stats.bearer_congs++;
1549                         msg_dbg(buf_msg(buf), "|>DEF-RETR>");
1550                         return PUSH_FAILED;
1551                 }
1552         }
1553
1554         /* Send deferred protocol message, if any: */
1555
1556         buf = l_ptr->proto_msg_queue;
1557         if (buf) {
1558                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1559                 msg_set_bcast_ack(buf_msg(buf),l_ptr->owner->bclink.last_in);
1560                 if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1561                         msg_dbg(buf_msg(buf), ">DEF-PROT>");
1562                         l_ptr->unacked_window = 0;
1563                         buf_discard(buf);
1564                         l_ptr->proto_msg_queue = NULL;
1565                         return TIPC_OK;
1566                 } else {
1567                         msg_dbg(buf_msg(buf), "|>DEF-PROT>");
1568                         l_ptr->stats.bearer_congs++;
1569                         return PUSH_FAILED;
1570                 }
1571         }
1572
1573         /* Send one deferred data message, if send window not full: */
1574
1575         buf = l_ptr->next_out;
1576         if (buf) {
1577                 struct tipc_msg *msg = buf_msg(buf);
1578                 u32 next = msg_seqno(msg);
1579                 u32 first = msg_seqno(buf_msg(l_ptr->first_out));
1580
1581                 if (mod(next - first) < l_ptr->queue_limit[0]) {
1582                         msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1583                         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1584                         if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1585                                 if (msg_user(msg) == MSG_BUNDLER)
1586                                         msg_set_type(msg, CLOSED_MSG);
1587                                 msg_dbg(msg, ">PUSH-DATA>");
1588                                 l_ptr->next_out = buf->next;
1589                                 return TIPC_OK;
1590                         } else {
1591                                 msg_dbg(msg, "|PUSH-DATA|");
1592                                 l_ptr->stats.bearer_congs++;
1593                                 return PUSH_FAILED;
1594                         }
1595                 }
1596         }
1597         return PUSH_FINISHED;
1598 }
1599
1600 /*
1601  * push_queue(): push out the unsent messages of a link where
1602  *               congestion has abated. Node is locked
1603  */
1604 void tipc_link_push_queue(struct link *l_ptr)
1605 {
1606         u32 res;
1607
1608         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr))
1609                 return;
1610
1611         do {
1612                 res = tipc_link_push_packet(l_ptr);
1613         }
1614         while (res == TIPC_OK);
1615         if (res == PUSH_FAILED)
1616                 tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1617 }
1618
1619 static void link_reset_all(unsigned long addr)
1620 {
1621         struct node *n_ptr;
1622         char addr_string[16];
1623         u32 i;
1624
1625         read_lock_bh(&tipc_net_lock);
1626         n_ptr = tipc_node_find((u32)addr);
1627         if (!n_ptr) {
1628                 read_unlock_bh(&tipc_net_lock);
1629                 return; /* node no longer exists */
1630         }
1631
1632         tipc_node_lock(n_ptr);
1633
1634         warn("Resetting all links to %s\n",
1635              addr_string_fill(addr_string, n_ptr->addr));
1636
1637         for (i = 0; i < MAX_BEARERS; i++) {
1638                 if (n_ptr->links[i]) {
1639                         link_print(n_ptr->links[i], TIPC_OUTPUT,
1640                                    "Resetting link\n");
1641                         tipc_link_reset(n_ptr->links[i]);
1642                 }
1643         }
1644
1645         tipc_node_unlock(n_ptr);
1646         read_unlock_bh(&tipc_net_lock);
1647 }
1648
1649 static void link_retransmit_failure(struct link *l_ptr, struct sk_buff *buf)
1650 {
1651         struct tipc_msg *msg = buf_msg(buf);
1652
1653         warn("Retransmission failure on link <%s>\n", l_ptr->name);
1654         tipc_msg_print(TIPC_OUTPUT, msg, ">RETR-FAIL>");
1655
1656         if (l_ptr->addr) {
1657
1658                 /* Handle failure on standard link */
1659
1660                 link_print(l_ptr, TIPC_OUTPUT, "Resetting link\n");
1661                 tipc_link_reset(l_ptr);
1662
1663         } else {
1664
1665                 /* Handle failure on broadcast link */
1666
1667                 struct node *n_ptr;
1668                 char addr_string[16];
1669
1670                 tipc_printf(TIPC_OUTPUT, "Msg seq number: %u,  ", msg_seqno(msg));
1671                 tipc_printf(TIPC_OUTPUT, "Outstanding acks: %lu\n",
1672                                      (unsigned long) TIPC_SKB_CB(buf)->handle);
1673
1674                 n_ptr = l_ptr->owner->next;
1675                 tipc_node_lock(n_ptr);
1676
1677                 addr_string_fill(addr_string, n_ptr->addr);
1678                 tipc_printf(TIPC_OUTPUT, "Multicast link info for %s\n", addr_string);
1679                 tipc_printf(TIPC_OUTPUT, "Supported: %d,  ", n_ptr->bclink.supported);
1680                 tipc_printf(TIPC_OUTPUT, "Acked: %u\n", n_ptr->bclink.acked);
1681                 tipc_printf(TIPC_OUTPUT, "Last in: %u,  ", n_ptr->bclink.last_in);
1682                 tipc_printf(TIPC_OUTPUT, "Gap after: %u,  ", n_ptr->bclink.gap_after);
1683                 tipc_printf(TIPC_OUTPUT, "Gap to: %u\n", n_ptr->bclink.gap_to);
1684                 tipc_printf(TIPC_OUTPUT, "Nack sync: %u\n\n", n_ptr->bclink.nack_sync);
1685
1686                 tipc_k_signal((Handler)link_reset_all, (unsigned long)n_ptr->addr);
1687
1688                 tipc_node_unlock(n_ptr);
1689
1690                 l_ptr->stale_count = 0;
1691         }
1692 }
1693
1694 void tipc_link_retransmit(struct link *l_ptr, struct sk_buff *buf,
1695                           u32 retransmits)
1696 {
1697         struct tipc_msg *msg;
1698
1699         if (!buf)
1700                 return;
1701
1702         msg = buf_msg(buf);
1703
1704         dbg("Retransmitting %u in link %x\n", retransmits, l_ptr);
1705
1706         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
1707                 if (!skb_cloned(buf)) {
1708                         msg_dbg(msg, ">NO_RETR->BCONG>");
1709                         dbg_print_link(l_ptr, "   ");
1710                         l_ptr->retransm_queue_head = msg_seqno(msg);
1711                         l_ptr->retransm_queue_size = retransmits;
1712                         return;
1713                 } else {
1714                         /* Don't retransmit if driver already has the buffer */
1715                 }
1716         } else {
1717                 /* Detect repeated retransmit failures on uncongested bearer */
1718
1719                 if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1720                         if (++l_ptr->stale_count > 100) {
1721                                 link_retransmit_failure(l_ptr, buf);
1722                                 return;
1723                         }
1724                 } else {
1725                         l_ptr->last_retransmitted = msg_seqno(msg);
1726                         l_ptr->stale_count = 1;
1727                 }
1728         }
1729
1730         while (retransmits && (buf != l_ptr->next_out) && buf && !skb_cloned(buf)) {
1731                 msg = buf_msg(buf);
1732                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1733                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1734                 if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1735                         msg_dbg(buf_msg(buf), ">RETR>");
1736                         buf = buf->next;
1737                         retransmits--;
1738                         l_ptr->stats.retransmitted++;
1739                 } else {
1740                         tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1741                         l_ptr->stats.bearer_congs++;
1742                         l_ptr->retransm_queue_head = msg_seqno(buf_msg(buf));
1743                         l_ptr->retransm_queue_size = retransmits;
1744                         return;
1745                 }
1746         }
1747
1748         l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
1749 }
1750
1751 /*
1752  * link_recv_non_seq: Receive packets which are outside
1753  *                    the link sequence flow
1754  */
1755
1756 static void link_recv_non_seq(struct sk_buff *buf)
1757 {
1758         struct tipc_msg *msg = buf_msg(buf);
1759
1760         if (msg_user(msg) ==  LINK_CONFIG)
1761                 tipc_disc_recv_msg(buf);
1762         else
1763                 tipc_bclink_recv_pkt(buf);
1764 }
1765
1766 /**
1767  * link_insert_deferred_queue - insert deferred messages back into receive chain
1768  */
1769
1770 static struct sk_buff *link_insert_deferred_queue(struct link *l_ptr,
1771                                                   struct sk_buff *buf)
1772 {
1773         u32 seq_no;
1774
1775         if (l_ptr->oldest_deferred_in == NULL)
1776                 return buf;
1777
1778         seq_no = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
1779         if (seq_no == mod(l_ptr->next_in_no)) {
1780                 l_ptr->newest_deferred_in->next = buf;
1781                 buf = l_ptr->oldest_deferred_in;
1782                 l_ptr->oldest_deferred_in = NULL;
1783                 l_ptr->deferred_inqueue_sz = 0;
1784         }
1785         return buf;
1786 }
1787
1788 void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *tb_ptr)
1789 {
1790         read_lock_bh(&tipc_net_lock);
1791         while (head) {
1792                 struct bearer *b_ptr;
1793                 struct node *n_ptr;
1794                 struct link *l_ptr;
1795                 struct sk_buff *crs;
1796                 struct sk_buff *buf = head;
1797                 struct tipc_msg *msg = buf_msg(buf);
1798                 u32 seq_no = msg_seqno(msg);
1799                 u32 ackd = msg_ack(msg);
1800                 u32 released = 0;
1801                 int type;
1802
1803                 b_ptr = (struct bearer *)tb_ptr;
1804                 TIPC_SKB_CB(buf)->handle = b_ptr;
1805
1806                 head = head->next;
1807                 if (unlikely(msg_version(msg) != TIPC_VERSION))
1808                         goto cont;
1809 #if 0
1810                 if (msg_user(msg) != LINK_PROTOCOL)
1811 #endif
1812                         msg_dbg(msg,"<REC<");
1813
1814                 if (unlikely(msg_non_seq(msg))) {
1815                         link_recv_non_seq(buf);
1816                         continue;
1817                 }
1818
1819                 if (unlikely(!msg_short(msg) &&
1820                              (msg_destnode(msg) != tipc_own_addr)))
1821                         goto cont;
1822
1823                 n_ptr = tipc_node_find(msg_prevnode(msg));
1824                 if (unlikely(!n_ptr))
1825                         goto cont;
1826
1827                 tipc_node_lock(n_ptr);
1828                 l_ptr = n_ptr->links[b_ptr->identity];
1829                 if (unlikely(!l_ptr)) {
1830                         tipc_node_unlock(n_ptr);
1831                         goto cont;
1832                 }
1833                 /*
1834                  * Release acked messages
1835                  */
1836                 if (less(n_ptr->bclink.acked, msg_bcast_ack(msg))) {
1837                         if (tipc_node_is_up(n_ptr) && n_ptr->bclink.supported)
1838                                 tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1839                 }
1840
1841                 crs = l_ptr->first_out;
1842                 while ((crs != l_ptr->next_out) &&
1843                        less_eq(msg_seqno(buf_msg(crs)), ackd)) {
1844                         struct sk_buff *next = crs->next;
1845
1846                         buf_discard(crs);
1847                         crs = next;
1848                         released++;
1849                 }
1850                 if (released) {
1851                         l_ptr->first_out = crs;
1852                         l_ptr->out_queue_size -= released;
1853                 }
1854                 if (unlikely(l_ptr->next_out))
1855                         tipc_link_push_queue(l_ptr);
1856                 if (unlikely(!list_empty(&l_ptr->waiting_ports)))
1857                         tipc_link_wakeup_ports(l_ptr, 0);
1858                 if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1859                         l_ptr->stats.sent_acks++;
1860                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1861                 }
1862
1863 protocol_check:
1864                 if (likely(link_working_working(l_ptr))) {
1865                         if (likely(seq_no == mod(l_ptr->next_in_no))) {
1866                                 l_ptr->next_in_no++;
1867                                 if (unlikely(l_ptr->oldest_deferred_in))
1868                                         head = link_insert_deferred_queue(l_ptr,
1869                                                                           head);
1870                                 if (likely(msg_is_dest(msg, tipc_own_addr))) {
1871 deliver:
1872                                         if (likely(msg_isdata(msg))) {
1873                                                 tipc_node_unlock(n_ptr);
1874                                                 tipc_port_recv_msg(buf);
1875                                                 continue;
1876                                         }
1877                                         switch (msg_user(msg)) {
1878                                         case MSG_BUNDLER:
1879                                                 l_ptr->stats.recv_bundles++;
1880                                                 l_ptr->stats.recv_bundled +=
1881                                                         msg_msgcnt(msg);
1882                                                 tipc_node_unlock(n_ptr);
1883                                                 tipc_link_recv_bundle(buf);
1884                                                 continue;
1885                                         case ROUTE_DISTRIBUTOR:
1886                                                 tipc_node_unlock(n_ptr);
1887                                                 tipc_cltr_recv_routing_table(buf);
1888                                                 continue;
1889                                         case NAME_DISTRIBUTOR:
1890                                                 tipc_node_unlock(n_ptr);
1891                                                 tipc_named_recv(buf);
1892                                                 continue;
1893                                         case CONN_MANAGER:
1894                                                 tipc_node_unlock(n_ptr);
1895                                                 tipc_port_recv_proto_msg(buf);
1896                                                 continue;
1897                                         case MSG_FRAGMENTER:
1898                                                 l_ptr->stats.recv_fragments++;
1899                                                 if (tipc_link_recv_fragment(&l_ptr->defragm_buf,
1900                                                                             &buf, &msg)) {
1901                                                         l_ptr->stats.recv_fragmented++;
1902                                                         goto deliver;
1903                                                 }
1904                                                 break;
1905                                         case CHANGEOVER_PROTOCOL:
1906                                                 type = msg_type(msg);
1907                                                 if (link_recv_changeover_msg(&l_ptr, &buf)) {
1908                                                         msg = buf_msg(buf);
1909                                                         seq_no = msg_seqno(msg);
1910                                                         TIPC_SKB_CB(buf)->handle
1911                                                                 = b_ptr;
1912                                                         if (type == ORIGINAL_MSG)
1913                                                                 goto deliver;
1914                                                         goto protocol_check;
1915                                                 }
1916                                                 break;
1917                                         }
1918                                 }
1919                                 tipc_node_unlock(n_ptr);
1920                                 tipc_net_route_msg(buf);
1921                                 continue;
1922                         }
1923                         link_handle_out_of_seq_msg(l_ptr, buf);
1924                         head = link_insert_deferred_queue(l_ptr, head);
1925                         tipc_node_unlock(n_ptr);
1926                         continue;
1927                 }
1928
1929                 if (msg_user(msg) == LINK_PROTOCOL) {
1930                         link_recv_proto_msg(l_ptr, buf);
1931                         head = link_insert_deferred_queue(l_ptr, head);
1932                         tipc_node_unlock(n_ptr);
1933                         continue;
1934                 }
1935                 msg_dbg(msg,"NSEQ<REC<");
1936                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1937
1938                 if (link_working_working(l_ptr)) {
1939                         /* Re-insert in front of queue */
1940                         msg_dbg(msg,"RECV-REINS:");
1941                         buf->next = head;
1942                         head = buf;
1943                         tipc_node_unlock(n_ptr);
1944                         continue;
1945                 }
1946                 tipc_node_unlock(n_ptr);
1947 cont:
1948                 buf_discard(buf);
1949         }
1950         read_unlock_bh(&tipc_net_lock);
1951 }
1952
1953 /*
1954  * link_defer_buf(): Sort a received out-of-sequence packet
1955  *                   into the deferred reception queue.
1956  * Returns the increase of the queue length,i.e. 0 or 1
1957  */
1958
1959 u32 tipc_link_defer_pkt(struct sk_buff **head,
1960                         struct sk_buff **tail,
1961                         struct sk_buff *buf)
1962 {
1963         struct sk_buff *prev = NULL;
1964         struct sk_buff *crs = *head;
1965         u32 seq_no = msg_seqno(buf_msg(buf));
1966
1967         buf->next = NULL;
1968
1969         /* Empty queue ? */
1970         if (*head == NULL) {
1971                 *head = *tail = buf;
1972                 return 1;
1973         }
1974
1975         /* Last ? */
1976         if (less(msg_seqno(buf_msg(*tail)), seq_no)) {
1977                 (*tail)->next = buf;
1978                 *tail = buf;
1979                 return 1;
1980         }
1981
1982         /* Scan through queue and sort it in */
1983         do {
1984                 struct tipc_msg *msg = buf_msg(crs);
1985
1986                 if (less(seq_no, msg_seqno(msg))) {
1987                         buf->next = crs;
1988                         if (prev)
1989                                 prev->next = buf;
1990                         else
1991                                 *head = buf;
1992                         return 1;
1993                 }
1994                 if (seq_no == msg_seqno(msg)) {
1995                         break;
1996                 }
1997                 prev = crs;
1998                 crs = crs->next;
1999         }
2000         while (crs);
2001
2002         /* Message is a duplicate of an existing message */
2003
2004         buf_discard(buf);
2005         return 0;
2006 }
2007
2008 /**
2009  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
2010  */
2011
2012 static void link_handle_out_of_seq_msg(struct link *l_ptr,
2013                                        struct sk_buff *buf)
2014 {
2015         u32 seq_no = msg_seqno(buf_msg(buf));
2016
2017         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
2018                 link_recv_proto_msg(l_ptr, buf);
2019                 return;
2020         }
2021
2022         dbg("rx OOS msg: seq_no %u, expecting %u (%u)\n",
2023             seq_no, mod(l_ptr->next_in_no), l_ptr->next_in_no);
2024
2025         /* Record OOS packet arrival (force mismatch on next timeout) */
2026
2027         l_ptr->checkpoint--;
2028
2029         /*
2030          * Discard packet if a duplicate; otherwise add it to deferred queue
2031          * and notify peer of gap as per protocol specification
2032          */
2033
2034         if (less(seq_no, mod(l_ptr->next_in_no))) {
2035                 l_ptr->stats.duplicates++;
2036                 buf_discard(buf);
2037                 return;
2038         }
2039
2040         if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
2041                                 &l_ptr->newest_deferred_in, buf)) {
2042                 l_ptr->deferred_inqueue_sz++;
2043                 l_ptr->stats.deferred_recv++;
2044                 if ((l_ptr->deferred_inqueue_sz % 16) == 1)
2045                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
2046         } else
2047                 l_ptr->stats.duplicates++;
2048 }
2049
2050 /*
2051  * Send protocol message to the other endpoint.
2052  */
2053 void tipc_link_send_proto_msg(struct link *l_ptr, u32 msg_typ, int probe_msg,
2054                               u32 gap, u32 tolerance, u32 priority, u32 ack_mtu)
2055 {
2056         struct sk_buff *buf = NULL;
2057         struct tipc_msg *msg = l_ptr->pmsg;
2058         u32 msg_size = sizeof(l_ptr->proto_msg);
2059
2060         if (link_blocked(l_ptr))
2061                 return;
2062         msg_set_type(msg, msg_typ);
2063         msg_set_net_plane(msg, l_ptr->b_ptr->net_plane);
2064         msg_set_bcast_ack(msg, mod(l_ptr->owner->bclink.last_in));
2065         msg_set_last_bcast(msg, tipc_bclink_get_last_sent());
2066
2067         if (msg_typ == STATE_MSG) {
2068                 u32 next_sent = mod(l_ptr->next_out_no);
2069
2070                 if (!tipc_link_is_up(l_ptr))
2071                         return;
2072                 if (l_ptr->next_out)
2073                         next_sent = msg_seqno(buf_msg(l_ptr->next_out));
2074                 msg_set_next_sent(msg, next_sent);
2075                 if (l_ptr->oldest_deferred_in) {
2076                         u32 rec = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
2077                         gap = mod(rec - mod(l_ptr->next_in_no));
2078                 }
2079                 msg_set_seq_gap(msg, gap);
2080                 if (gap)
2081                         l_ptr->stats.sent_nacks++;
2082                 msg_set_link_tolerance(msg, tolerance);
2083                 msg_set_linkprio(msg, priority);
2084                 msg_set_max_pkt(msg, ack_mtu);
2085                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
2086                 msg_set_probe(msg, probe_msg != 0);
2087                 if (probe_msg) {
2088                         u32 mtu = l_ptr->max_pkt;
2089
2090                         if ((mtu < l_ptr->max_pkt_target) &&
2091                             link_working_working(l_ptr) &&
2092                             l_ptr->fsm_msg_cnt) {
2093                                 msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
2094                                 if (l_ptr->max_pkt_probes == 10) {
2095                                         l_ptr->max_pkt_target = (msg_size - 4);
2096                                         l_ptr->max_pkt_probes = 0;
2097                                         msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
2098                                 }
2099                                 l_ptr->max_pkt_probes++;
2100                         }
2101
2102                         l_ptr->stats.sent_probes++;
2103                 }
2104                 l_ptr->stats.sent_states++;
2105         } else {                /* RESET_MSG or ACTIVATE_MSG */
2106                 msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
2107                 msg_set_seq_gap(msg, 0);
2108                 msg_set_next_sent(msg, 1);
2109                 msg_set_link_tolerance(msg, l_ptr->tolerance);
2110                 msg_set_linkprio(msg, l_ptr->priority);
2111                 msg_set_max_pkt(msg, l_ptr->max_pkt_target);
2112         }
2113
2114         if (tipc_node_has_redundant_links(l_ptr->owner)) {
2115                 msg_set_redundant_link(msg);
2116         } else {
2117                 msg_clear_redundant_link(msg);
2118         }
2119         msg_set_linkprio(msg, l_ptr->priority);
2120
2121         /* Ensure sequence number will not fit : */
2122
2123         msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
2124
2125         /* Congestion? */
2126
2127         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
2128                 if (!l_ptr->proto_msg_queue) {
2129                         l_ptr->proto_msg_queue =
2130                                 buf_acquire(sizeof(l_ptr->proto_msg));
2131                 }
2132                 buf = l_ptr->proto_msg_queue;
2133                 if (!buf)
2134                         return;
2135                 skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
2136                 return;
2137         }
2138         msg_set_timestamp(msg, jiffies_to_msecs(jiffies));
2139
2140         /* Message can be sent */
2141
2142         msg_dbg(msg, ">>");
2143
2144         buf = buf_acquire(msg_size);
2145         if (!buf)
2146                 return;
2147
2148         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
2149         msg_set_size(buf_msg(buf), msg_size);
2150
2151         if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
2152                 l_ptr->unacked_window = 0;
2153                 buf_discard(buf);
2154                 return;
2155         }
2156
2157         /* New congestion */
2158         tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
2159         l_ptr->proto_msg_queue = buf;
2160         l_ptr->stats.bearer_congs++;
2161 }
2162
2163 /*
2164  * Receive protocol message :
2165  * Note that network plane id propagates through the network, and may
2166  * change at any time. The node with lowest address rules
2167  */
2168
2169 static void link_recv_proto_msg(struct link *l_ptr, struct sk_buff *buf)
2170 {
2171         u32 rec_gap = 0;
2172         u32 max_pkt_info;
2173         u32 max_pkt_ack;
2174         u32 msg_tol;
2175         struct tipc_msg *msg = buf_msg(buf);
2176
2177         dbg("AT(%u):", jiffies_to_msecs(jiffies));
2178         msg_dbg(msg, "<<");
2179         if (link_blocked(l_ptr))
2180                 goto exit;
2181
2182         /* record unnumbered packet arrival (force mismatch on next timeout) */
2183
2184         l_ptr->checkpoint--;
2185
2186         if (l_ptr->b_ptr->net_plane != msg_net_plane(msg))
2187                 if (tipc_own_addr > msg_prevnode(msg))
2188                         l_ptr->b_ptr->net_plane = msg_net_plane(msg);
2189
2190         l_ptr->owner->permit_changeover = msg_redundant_link(msg);
2191
2192         switch (msg_type(msg)) {
2193
2194         case RESET_MSG:
2195                 if (!link_working_unknown(l_ptr) && l_ptr->peer_session) {
2196                         if (msg_session(msg) == l_ptr->peer_session) {
2197                                 dbg("Duplicate RESET: %u<->%u\n",
2198                                     msg_session(msg), l_ptr->peer_session);
2199                                 break; /* duplicate: ignore */
2200                         }
2201                 }
2202                 /* fall thru' */
2203         case ACTIVATE_MSG:
2204                 /* Update link settings according other endpoint's values */
2205
2206                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
2207
2208                 if ((msg_tol = msg_link_tolerance(msg)) &&
2209                     (msg_tol > l_ptr->tolerance))
2210                         link_set_supervision_props(l_ptr, msg_tol);
2211
2212                 if (msg_linkprio(msg) > l_ptr->priority)
2213                         l_ptr->priority = msg_linkprio(msg);
2214
2215                 max_pkt_info = msg_max_pkt(msg);
2216                 if (max_pkt_info) {
2217                         if (max_pkt_info < l_ptr->max_pkt_target)
2218                                 l_ptr->max_pkt_target = max_pkt_info;
2219                         if (l_ptr->max_pkt > l_ptr->max_pkt_target)
2220                                 l_ptr->max_pkt = l_ptr->max_pkt_target;
2221                 } else {
2222                         l_ptr->max_pkt = l_ptr->max_pkt_target;
2223                 }
2224                 l_ptr->owner->bclink.supported = (max_pkt_info != 0);
2225
2226                 link_state_event(l_ptr, msg_type(msg));
2227
2228                 l_ptr->peer_session = msg_session(msg);
2229                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
2230
2231                 /* Synchronize broadcast sequence numbers */
2232                 if (!tipc_node_has_redundant_links(l_ptr->owner)) {
2233                         l_ptr->owner->bclink.last_in = mod(msg_last_bcast(msg));
2234                 }
2235                 break;
2236         case STATE_MSG:
2237
2238                 if ((msg_tol = msg_link_tolerance(msg)))
2239                         link_set_supervision_props(l_ptr, msg_tol);
2240
2241                 if (msg_linkprio(msg) &&
2242                     (msg_linkprio(msg) != l_ptr->priority)) {
2243                         warn("Resetting link <%s>, priority change %u->%u\n",
2244                              l_ptr->name, l_ptr->priority, msg_linkprio(msg));
2245                         l_ptr->priority = msg_linkprio(msg);
2246                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
2247                         break;
2248                 }
2249                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
2250                 l_ptr->stats.recv_states++;
2251                 if (link_reset_unknown(l_ptr))
2252                         break;
2253
2254                 if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
2255                         rec_gap = mod(msg_next_sent(msg) -
2256                                       mod(l_ptr->next_in_no));
2257                 }
2258
2259                 max_pkt_ack = msg_max_pkt(msg);
2260                 if (max_pkt_ack > l_ptr->max_pkt) {
2261                         dbg("Link <%s> updated MTU %u -> %u\n",
2262                             l_ptr->name, l_ptr->max_pkt, max_pkt_ack);
2263                         l_ptr->max_pkt = max_pkt_ack;
2264                         l_ptr->max_pkt_probes = 0;
2265                 }
2266
2267                 max_pkt_ack = 0;
2268                 if (msg_probe(msg)) {
2269                         l_ptr->stats.recv_probes++;
2270                         if (msg_size(msg) > sizeof(l_ptr->proto_msg)) {
2271                                 max_pkt_ack = msg_size(msg);
2272                         }
2273                 }
2274
2275                 /* Protocol message before retransmits, reduce loss risk */
2276
2277                 tipc_bclink_check_gap(l_ptr->owner, msg_last_bcast(msg));
2278
2279                 if (rec_gap || (msg_probe(msg))) {
2280                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2281                                                  0, rec_gap, 0, 0, max_pkt_ack);
2282                 }
2283                 if (msg_seq_gap(msg)) {
2284                         msg_dbg(msg, "With Gap:");
2285                         l_ptr->stats.recv_nacks++;
2286                         tipc_link_retransmit(l_ptr, l_ptr->first_out,
2287                                              msg_seq_gap(msg));
2288                 }
2289                 break;
2290         default:
2291                 msg_dbg(buf_msg(buf), "<DISCARDING UNKNOWN<");
2292         }
2293 exit:
2294         buf_discard(buf);
2295 }
2296
2297
2298 /*
2299  * tipc_link_tunnel(): Send one message via a link belonging to
2300  * another bearer. Owner node is locked.
2301  */
2302 void tipc_link_tunnel(struct link *l_ptr,
2303                       struct tipc_msg *tunnel_hdr,
2304                       struct tipc_msg  *msg,
2305                       u32 selector)
2306 {
2307         struct link *tunnel;
2308         struct sk_buff *buf;
2309         u32 length = msg_size(msg);
2310
2311         tunnel = l_ptr->owner->active_links[selector & 1];
2312         if (!tipc_link_is_up(tunnel)) {
2313                 warn("Link changeover error, "
2314                      "tunnel link no longer available\n");
2315                 return;
2316         }
2317         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
2318         buf = buf_acquire(length + INT_H_SIZE);
2319         if (!buf) {
2320                 warn("Link changeover error, "
2321                      "unable to send tunnel msg\n");
2322                 return;
2323         }
2324         skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
2325         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, msg, length);
2326         dbg("%c->%c:", l_ptr->b_ptr->net_plane, tunnel->b_ptr->net_plane);
2327         msg_dbg(buf_msg(buf), ">SEND>");
2328         tipc_link_send_buf(tunnel, buf);
2329 }
2330
2331
2332
2333 /*
2334  * changeover(): Send whole message queue via the remaining link
2335  *               Owner node is locked.
2336  */
2337
2338 void tipc_link_changeover(struct link *l_ptr)
2339 {
2340         u32 msgcount = l_ptr->out_queue_size;
2341         struct sk_buff *crs = l_ptr->first_out;
2342         struct link *tunnel = l_ptr->owner->active_links[0];
2343         struct tipc_msg tunnel_hdr;
2344         int split_bundles;
2345
2346         if (!tunnel)
2347                 return;
2348
2349         if (!l_ptr->owner->permit_changeover) {
2350                 warn("Link changeover error, "
2351                      "peer did not permit changeover\n");
2352                 return;
2353         }
2354
2355         msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2356                  ORIGINAL_MSG, TIPC_OK, INT_H_SIZE, l_ptr->addr);
2357         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2358         msg_set_msgcnt(&tunnel_hdr, msgcount);
2359         dbg("Link changeover requires %u tunnel messages\n", msgcount);
2360
2361         if (!l_ptr->first_out) {
2362                 struct sk_buff *buf;
2363
2364                 buf = buf_acquire(INT_H_SIZE);
2365                 if (buf) {
2366                         skb_copy_to_linear_data(buf, &tunnel_hdr, INT_H_SIZE);
2367                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
2368                         dbg("%c->%c:", l_ptr->b_ptr->net_plane,
2369                             tunnel->b_ptr->net_plane);
2370                         msg_dbg(&tunnel_hdr, "EMPTY>SEND>");
2371                         tipc_link_send_buf(tunnel, buf);
2372                 } else {
2373                         warn("Link changeover error, "
2374                              "unable to send changeover msg\n");
2375                 }
2376                 return;
2377         }
2378
2379         split_bundles = (l_ptr->owner->active_links[0] !=
2380                          l_ptr->owner->active_links[1]);
2381
2382         while (crs) {
2383                 struct tipc_msg *msg = buf_msg(crs);
2384
2385                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
2386                         struct tipc_msg *m = msg_get_wrapped(msg);
2387                         unchar* pos = (unchar*)m;
2388
2389                         msgcount = msg_msgcnt(msg);
2390                         while (msgcount--) {
2391                                 msg_set_seqno(m,msg_seqno(msg));
2392                                 tipc_link_tunnel(l_ptr, &tunnel_hdr, m,
2393                                                  msg_link_selector(m));
2394                                 pos += align(msg_size(m));
2395                                 m = (struct tipc_msg *)pos;
2396                         }
2397                 } else {
2398                         tipc_link_tunnel(l_ptr, &tunnel_hdr, msg,
2399                                          msg_link_selector(msg));
2400                 }
2401                 crs = crs->next;
2402         }
2403 }
2404
2405 void tipc_link_send_duplicate(struct link *l_ptr, struct link *tunnel)
2406 {
2407         struct sk_buff *iter;
2408         struct tipc_msg tunnel_hdr;
2409
2410         msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2411                  DUPLICATE_MSG, TIPC_OK, INT_H_SIZE, l_ptr->addr);
2412         msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
2413         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2414         iter = l_ptr->first_out;
2415         while (iter) {
2416                 struct sk_buff *outbuf;
2417                 struct tipc_msg *msg = buf_msg(iter);
2418                 u32 length = msg_size(msg);
2419
2420                 if (msg_user(msg) == MSG_BUNDLER)
2421                         msg_set_type(msg, CLOSED_MSG);
2422                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));   /* Update */
2423                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
2424                 msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
2425                 outbuf = buf_acquire(length + INT_H_SIZE);
2426                 if (outbuf == NULL) {
2427                         warn("Link changeover error, "
2428                              "unable to send duplicate msg\n");
2429                         return;
2430                 }
2431                 skb_copy_to_linear_data(outbuf, &tunnel_hdr, INT_H_SIZE);
2432                 skb_copy_to_linear_data_offset(outbuf, INT_H_SIZE, iter->data,
2433                                                length);
2434                 dbg("%c->%c:", l_ptr->b_ptr->net_plane,
2435                     tunnel->b_ptr->net_plane);
2436                 msg_dbg(buf_msg(outbuf), ">SEND>");
2437                 tipc_link_send_buf(tunnel, outbuf);
2438                 if (!tipc_link_is_up(l_ptr))
2439                         return;
2440                 iter = iter->next;
2441         }
2442 }
2443
2444
2445
2446 /**
2447  * buf_extract - extracts embedded TIPC message from another message
2448  * @skb: encapsulating message buffer
2449  * @from_pos: offset to extract from
2450  *
2451  * Returns a new message buffer containing an embedded message.  The
2452  * encapsulating message itself is left unchanged.
2453  */
2454
2455 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
2456 {
2457         struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
2458         u32 size = msg_size(msg);
2459         struct sk_buff *eb;
2460
2461         eb = buf_acquire(size);
2462         if (eb)
2463                 skb_copy_to_linear_data(eb, msg, size);
2464         return eb;
2465 }
2466
2467 /*
2468  *  link_recv_changeover_msg(): Receive tunneled packet sent
2469  *  via other link. Node is locked. Return extracted buffer.
2470  */
2471
2472 static int link_recv_changeover_msg(struct link **l_ptr,
2473                                     struct sk_buff **buf)
2474 {
2475         struct sk_buff *tunnel_buf = *buf;
2476         struct link *dest_link;
2477         struct tipc_msg *msg;
2478         struct tipc_msg *tunnel_msg = buf_msg(tunnel_buf);
2479         u32 msg_typ = msg_type(tunnel_msg);
2480         u32 msg_count = msg_msgcnt(tunnel_msg);
2481
2482         dest_link = (*l_ptr)->owner->links[msg_bearer_id(tunnel_msg)];
2483         if (!dest_link) {
2484                 msg_dbg(tunnel_msg, "NOLINK/<REC<");
2485                 goto exit;
2486         }
2487         if (dest_link == *l_ptr) {
2488                 err("Unexpected changeover message on link <%s>\n",
2489                     (*l_ptr)->name);
2490                 goto exit;
2491         }
2492         dbg("%c<-%c:", dest_link->b_ptr->net_plane,
2493             (*l_ptr)->b_ptr->net_plane);
2494         *l_ptr = dest_link;
2495         msg = msg_get_wrapped(tunnel_msg);
2496
2497         if (msg_typ == DUPLICATE_MSG) {
2498                 if (less(msg_seqno(msg), mod(dest_link->next_in_no))) {
2499                         msg_dbg(tunnel_msg, "DROP/<REC<");
2500                         goto exit;
2501                 }
2502                 *buf = buf_extract(tunnel_buf,INT_H_SIZE);
2503                 if (*buf == NULL) {
2504                         warn("Link changeover error, duplicate msg dropped\n");
2505                         goto exit;
2506                 }
2507                 msg_dbg(tunnel_msg, "TNL<REC<");
2508                 buf_discard(tunnel_buf);
2509                 return 1;
2510         }
2511
2512         /* First original message ?: */
2513
2514         if (tipc_link_is_up(dest_link)) {
2515                 msg_dbg(tunnel_msg, "UP/FIRST/<REC<");
2516                 info("Resetting link <%s>, changeover initiated by peer\n",
2517                      dest_link->name);
2518                 tipc_link_reset(dest_link);
2519                 dest_link->exp_msg_count = msg_count;
2520                 dbg("Expecting %u tunnelled messages\n", msg_count);
2521                 if (!msg_count)
2522                         goto exit;
2523         } else if (dest_link->exp_msg_count == START_CHANGEOVER) {
2524                 msg_dbg(tunnel_msg, "BLK/FIRST/<REC<");
2525                 dest_link->exp_msg_count = msg_count;
2526                 dbg("Expecting %u tunnelled messages\n", msg_count);
2527                 if (!msg_count)
2528                         goto exit;
2529         }
2530
2531         /* Receive original message */
2532
2533         if (dest_link->exp_msg_count == 0) {
2534                 warn("Link switchover error, "
2535                      "got too many tunnelled messages\n");
2536                 msg_dbg(tunnel_msg, "OVERDUE/DROP/<REC<");
2537                 dbg_print_link(dest_link, "LINK:");
2538                 goto exit;
2539         }
2540         dest_link->exp_msg_count--;
2541         if (less(msg_seqno(msg), dest_link->reset_checkpoint)) {
2542                 msg_dbg(tunnel_msg, "DROP/DUPL/<REC<");
2543                 goto exit;
2544         } else {
2545                 *buf = buf_extract(tunnel_buf, INT_H_SIZE);
2546                 if (*buf != NULL) {
2547                         msg_dbg(tunnel_msg, "TNL<REC<");
2548                         buf_discard(tunnel_buf);
2549                         return 1;
2550                 } else {
2551                         warn("Link changeover error, original msg dropped\n");
2552                 }
2553         }
2554 exit:
2555         *buf = NULL;
2556         buf_discard(tunnel_buf);
2557         return 0;
2558 }
2559
2560 /*
2561  *  Bundler functionality:
2562  */
2563 void tipc_link_recv_bundle(struct sk_buff *buf)
2564 {
2565         u32 msgcount = msg_msgcnt(buf_msg(buf));
2566         u32 pos = INT_H_SIZE;
2567         struct sk_buff *obuf;
2568
2569         msg_dbg(buf_msg(buf), "<BNDL<: ");
2570         while (msgcount--) {
2571                 obuf = buf_extract(buf, pos);
2572                 if (obuf == NULL) {
2573                         warn("Link unable to unbundle message(s)\n");
2574                         break;
2575                 }
2576                 pos += align(msg_size(buf_msg(obuf)));
2577                 msg_dbg(buf_msg(obuf), "     /");
2578                 tipc_net_route_msg(obuf);
2579         }
2580         buf_discard(buf);
2581 }
2582
2583 /*
2584  *  Fragmentation/defragmentation:
2585  */
2586
2587
2588 /*
2589  * tipc_link_send_long_buf: Entry for buffers needing fragmentation.
2590  * The buffer is complete, inclusive total message length.
2591  * Returns user data length.
2592  */
2593 int tipc_link_send_long_buf(struct link *l_ptr, struct sk_buff *buf)
2594 {
2595         struct tipc_msg *inmsg = buf_msg(buf);
2596         struct tipc_msg fragm_hdr;
2597         u32 insize = msg_size(inmsg);
2598         u32 dsz = msg_data_sz(inmsg);
2599         unchar *crs = buf->data;
2600         u32 rest = insize;
2601         u32 pack_sz = link_max_pkt(l_ptr);
2602         u32 fragm_sz = pack_sz - INT_H_SIZE;
2603         u32 fragm_no = 1;
2604         u32 destaddr = msg_destnode(inmsg);
2605
2606         if (msg_short(inmsg))
2607                 destaddr = l_ptr->addr;
2608
2609         if (msg_routed(inmsg))
2610                 msg_set_prevnode(inmsg, tipc_own_addr);
2611
2612         /* Prepare reusable fragment header: */
2613
2614         msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
2615                  TIPC_OK, INT_H_SIZE, destaddr);
2616         msg_set_link_selector(&fragm_hdr, msg_link_selector(inmsg));
2617         msg_set_long_msgno(&fragm_hdr, mod(l_ptr->long_msg_seq_no++));
2618         msg_set_fragm_no(&fragm_hdr, fragm_no);
2619         l_ptr->stats.sent_fragmented++;
2620
2621         /* Chop up message: */
2622
2623         while (rest > 0) {
2624                 struct sk_buff *fragm;
2625
2626                 if (rest <= fragm_sz) {
2627                         fragm_sz = rest;
2628                         msg_set_type(&fragm_hdr, LAST_FRAGMENT);
2629                 }
2630                 fragm = buf_acquire(fragm_sz + INT_H_SIZE);
2631                 if (fragm == NULL) {
2632                         warn("Link unable to fragment message\n");
2633                         dsz = -ENOMEM;
2634                         goto exit;
2635                 }
2636                 msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
2637                 skb_copy_to_linear_data(fragm, &fragm_hdr, INT_H_SIZE);
2638                 skb_copy_to_linear_data_offset(fragm, INT_H_SIZE, crs,
2639                                                fragm_sz);
2640                 /*  Send queued messages first, if any: */
2641
2642                 l_ptr->stats.sent_fragments++;
2643                 tipc_link_send_buf(l_ptr, fragm);
2644                 if (!tipc_link_is_up(l_ptr))
2645                         return dsz;
2646                 msg_set_fragm_no(&fragm_hdr, ++fragm_no);
2647                 rest -= fragm_sz;
2648                 crs += fragm_sz;
2649                 msg_set_type(&fragm_hdr, FRAGMENT);
2650         }
2651 exit:
2652         buf_discard(buf);
2653         return dsz;
2654 }
2655
2656 /*
2657  * A pending message being re-assembled must store certain values
2658  * to handle subsequent fragments correctly. The following functions
2659  * help storing these values in unused, available fields in the
2660  * pending message. This makes dynamic memory allocation unecessary.
2661  */
2662
2663 static void set_long_msg_seqno(struct sk_buff *buf, u32 seqno)
2664 {
2665         msg_set_seqno(buf_msg(buf), seqno);
2666 }
2667
2668 static u32 get_fragm_size(struct sk_buff *buf)
2669 {
2670         return msg_ack(buf_msg(buf));
2671 }
2672
2673 static void set_fragm_size(struct sk_buff *buf, u32 sz)
2674 {
2675         msg_set_ack(buf_msg(buf), sz);
2676 }
2677
2678 static u32 get_expected_frags(struct sk_buff *buf)
2679 {
2680         return msg_bcast_ack(buf_msg(buf));
2681 }
2682
2683 static void set_expected_frags(struct sk_buff *buf, u32 exp)
2684 {
2685         msg_set_bcast_ack(buf_msg(buf), exp);
2686 }
2687
2688 static u32 get_timer_cnt(struct sk_buff *buf)
2689 {
2690         return msg_reroute_cnt(buf_msg(buf));
2691 }
2692
2693 static void incr_timer_cnt(struct sk_buff *buf)
2694 {
2695         msg_incr_reroute_cnt(buf_msg(buf));
2696 }
2697
2698 /*
2699  * tipc_link_recv_fragment(): Called with node lock on. Returns
2700  * the reassembled buffer if message is complete.
2701  */
2702 int tipc_link_recv_fragment(struct sk_buff **pending, struct sk_buff **fb,
2703                             struct tipc_msg **m)
2704 {
2705         struct sk_buff *prev = NULL;
2706         struct sk_buff *fbuf = *fb;
2707         struct tipc_msg *fragm = buf_msg(fbuf);
2708         struct sk_buff *pbuf = *pending;
2709         u32 long_msg_seq_no = msg_long_msgno(fragm);
2710
2711         *fb = NULL;
2712         msg_dbg(fragm,"FRG<REC<");
2713
2714         /* Is there an incomplete message waiting for this fragment? */
2715
2716         while (pbuf && ((msg_seqno(buf_msg(pbuf)) != long_msg_seq_no)
2717                         || (msg_orignode(fragm) != msg_orignode(buf_msg(pbuf))))) {
2718                 prev = pbuf;
2719                 pbuf = pbuf->next;
2720         }
2721
2722         if (!pbuf && (msg_type(fragm) == FIRST_FRAGMENT)) {
2723                 struct tipc_msg *imsg = (struct tipc_msg *)msg_data(fragm);
2724                 u32 msg_sz = msg_size(imsg);
2725                 u32 fragm_sz = msg_data_sz(fragm);
2726                 u32 exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz);
2727                 u32 max =  TIPC_MAX_USER_MSG_SIZE + LONG_H_SIZE;
2728                 if (msg_type(imsg) == TIPC_MCAST_MSG)
2729                         max = TIPC_MAX_USER_MSG_SIZE + MCAST_H_SIZE;
2730                 if (msg_size(imsg) > max) {
2731                         msg_dbg(fragm,"<REC<Oversized: ");
2732                         buf_discard(fbuf);
2733                         return 0;
2734                 }
2735                 pbuf = buf_acquire(msg_size(imsg));
2736                 if (pbuf != NULL) {
2737                         pbuf->next = *pending;
2738                         *pending = pbuf;
2739                         skb_copy_to_linear_data(pbuf, imsg,
2740                                                 msg_data_sz(fragm));
2741                         /*  Prepare buffer for subsequent fragments. */
2742
2743                         set_long_msg_seqno(pbuf, long_msg_seq_no);
2744                         set_fragm_size(pbuf,fragm_sz);
2745                         set_expected_frags(pbuf,exp_fragm_cnt - 1);
2746                 } else {
2747                         warn("Link unable to reassemble fragmented message\n");
2748                 }
2749                 buf_discard(fbuf);
2750                 return 0;
2751         } else if (pbuf && (msg_type(fragm) != FIRST_FRAGMENT)) {
2752                 u32 dsz = msg_data_sz(fragm);
2753                 u32 fsz = get_fragm_size(pbuf);
2754                 u32 crs = ((msg_fragm_no(fragm) - 1) * fsz);
2755                 u32 exp_frags = get_expected_frags(pbuf) - 1;
2756                 skb_copy_to_linear_data_offset(pbuf, crs,
2757                                                msg_data(fragm), dsz);
2758                 buf_discard(fbuf);
2759
2760                 /* Is message complete? */
2761
2762                 if (exp_frags == 0) {
2763                         if (prev)
2764                                 prev->next = pbuf->next;
2765                         else
2766                                 *pending = pbuf->next;
2767                         msg_reset_reroute_cnt(buf_msg(pbuf));
2768                         *fb = pbuf;
2769                         *m = buf_msg(pbuf);
2770                         return 1;
2771                 }
2772                 set_expected_frags(pbuf,exp_frags);
2773                 return 0;
2774         }
2775         dbg(" Discarding orphan fragment %x\n",fbuf);
2776         msg_dbg(fragm,"ORPHAN:");
2777         dbg("Pending long buffers:\n");
2778         dbg_print_buf_chain(*pending);
2779         buf_discard(fbuf);
2780         return 0;
2781 }
2782
2783 /**
2784  * link_check_defragm_bufs - flush stale incoming message fragments
2785  * @l_ptr: pointer to link
2786  */
2787
2788 static void link_check_defragm_bufs(struct link *l_ptr)
2789 {
2790         struct sk_buff *prev = NULL;
2791         struct sk_buff *next = NULL;
2792         struct sk_buff *buf = l_ptr->defragm_buf;
2793
2794         if (!buf)
2795                 return;
2796         if (!link_working_working(l_ptr))
2797                 return;
2798         while (buf) {
2799                 u32 cnt = get_timer_cnt(buf);
2800
2801                 next = buf->next;
2802                 if (cnt < 4) {
2803                         incr_timer_cnt(buf);
2804                         prev = buf;
2805                 } else {
2806                         dbg(" Discarding incomplete long buffer\n");
2807                         msg_dbg(buf_msg(buf), "LONG:");
2808                         dbg_print_link(l_ptr, "curr:");
2809                         dbg("Pending long buffers:\n");
2810                         dbg_print_buf_chain(l_ptr->defragm_buf);
2811                         if (prev)
2812                                 prev->next = buf->next;
2813                         else
2814                                 l_ptr->defragm_buf = buf->next;
2815                         buf_discard(buf);
2816                 }
2817                 buf = next;
2818         }
2819 }
2820
2821
2822
2823 static void link_set_supervision_props(struct link *l_ptr, u32 tolerance)
2824 {
2825         l_ptr->tolerance = tolerance;
2826         l_ptr->continuity_interval =
2827                 ((tolerance / 4) > 500) ? 500 : tolerance / 4;
2828         l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
2829 }
2830
2831
2832 void tipc_link_set_queue_limits(struct link *l_ptr, u32 window)
2833 {
2834         /* Data messages from this node, inclusive FIRST_FRAGM */
2835         l_ptr->queue_limit[DATA_LOW] = window;
2836         l_ptr->queue_limit[DATA_MEDIUM] = (window / 3) * 4;
2837         l_ptr->queue_limit[DATA_HIGH] = (window / 3) * 5;
2838         l_ptr->queue_limit[DATA_CRITICAL] = (window / 3) * 6;
2839         /* Transiting data messages,inclusive FIRST_FRAGM */
2840         l_ptr->queue_limit[DATA_LOW + 4] = 300;
2841         l_ptr->queue_limit[DATA_MEDIUM + 4] = 600;
2842         l_ptr->queue_limit[DATA_HIGH + 4] = 900;
2843         l_ptr->queue_limit[DATA_CRITICAL + 4] = 1200;
2844         l_ptr->queue_limit[CONN_MANAGER] = 1200;
2845         l_ptr->queue_limit[ROUTE_DISTRIBUTOR] = 1200;
2846         l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
2847         l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
2848         /* FRAGMENT and LAST_FRAGMENT packets */
2849         l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
2850 }
2851
2852 /**
2853  * link_find_link - locate link by name
2854  * @name - ptr to link name string
2855  * @node - ptr to area to be filled with ptr to associated node
2856  *
2857  * Caller must hold 'tipc_net_lock' to ensure node and bearer are not deleted;
2858  * this also prevents link deletion.
2859  *
2860  * Returns pointer to link (or 0 if invalid link name).
2861  */
2862
2863 static struct link *link_find_link(const char *name, struct node **node)
2864 {
2865         struct link_name link_name_parts;
2866         struct bearer *b_ptr;
2867         struct link *l_ptr;
2868
2869         if (!link_name_validate(name, &link_name_parts))
2870                 return NULL;
2871
2872         b_ptr = tipc_bearer_find_interface(link_name_parts.if_local);
2873         if (!b_ptr)
2874                 return NULL;
2875
2876         *node = tipc_node_find(link_name_parts.addr_peer);
2877         if (!*node)
2878                 return NULL;
2879
2880         l_ptr = (*node)->links[b_ptr->identity];
2881         if (!l_ptr || strcmp(l_ptr->name, name))
2882                 return NULL;
2883
2884         return l_ptr;
2885 }
2886
2887 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2888                                      u16 cmd)
2889 {
2890         struct tipc_link_config *args;
2891         u32 new_value;
2892         struct link *l_ptr;
2893         struct node *node;
2894         int res;
2895
2896         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2897                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2898
2899         args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2900         new_value = ntohl(args->value);
2901
2902         if (!strcmp(args->name, tipc_bclink_name)) {
2903                 if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2904                     (tipc_bclink_set_queue_limits(new_value) == 0))
2905                         return tipc_cfg_reply_none();
2906                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2907                                                    " (cannot change setting on broadcast link)");
2908         }
2909
2910         read_lock_bh(&tipc_net_lock);
2911         l_ptr = link_find_link(args->name, &node);
2912         if (!l_ptr) {
2913                 read_unlock_bh(&tipc_net_lock);
2914                 return tipc_cfg_reply_error_string("link not found");
2915         }
2916
2917         tipc_node_lock(node);
2918         res = -EINVAL;
2919         switch (cmd) {
2920         case TIPC_CMD_SET_LINK_TOL:
2921                 if ((new_value >= TIPC_MIN_LINK_TOL) &&
2922                     (new_value <= TIPC_MAX_LINK_TOL)) {
2923                         link_set_supervision_props(l_ptr, new_value);
2924                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2925                                                  0, 0, new_value, 0, 0);
2926                         res = TIPC_OK;
2927                 }
2928                 break;
2929         case TIPC_CMD_SET_LINK_PRI:
2930                 if ((new_value >= TIPC_MIN_LINK_PRI) &&
2931                     (new_value <= TIPC_MAX_LINK_PRI)) {
2932                         l_ptr->priority = new_value;
2933                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2934                                                  0, 0, 0, new_value, 0);
2935                         res = TIPC_OK;
2936                 }
2937                 break;
2938         case TIPC_CMD_SET_LINK_WINDOW:
2939                 if ((new_value >= TIPC_MIN_LINK_WIN) &&
2940                     (new_value <= TIPC_MAX_LINK_WIN)) {
2941                         tipc_link_set_queue_limits(l_ptr, new_value);
2942                         res = TIPC_OK;
2943                 }
2944                 break;
2945         }
2946         tipc_node_unlock(node);
2947
2948         read_unlock_bh(&tipc_net_lock);
2949         if (res)
2950                 return tipc_cfg_reply_error_string("cannot change link setting");
2951
2952         return tipc_cfg_reply_none();
2953 }
2954
2955 /**
2956  * link_reset_statistics - reset link statistics
2957  * @l_ptr: pointer to link
2958  */
2959
2960 static void link_reset_statistics(struct link *l_ptr)
2961 {
2962         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
2963         l_ptr->stats.sent_info = l_ptr->next_out_no;
2964         l_ptr->stats.recv_info = l_ptr->next_in_no;
2965 }
2966
2967 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
2968 {
2969         char *link_name;
2970         struct link *l_ptr;
2971         struct node *node;
2972
2973         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2974                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2975
2976         link_name = (char *)TLV_DATA(req_tlv_area);
2977         if (!strcmp(link_name, tipc_bclink_name)) {
2978                 if (tipc_bclink_reset_stats())
2979                         return tipc_cfg_reply_error_string("link not found");
2980                 return tipc_cfg_reply_none();
2981         }
2982
2983         read_lock_bh(&tipc_net_lock);
2984         l_ptr = link_find_link(link_name, &node);
2985         if (!l_ptr) {
2986                 read_unlock_bh(&tipc_net_lock);
2987                 return tipc_cfg_reply_error_string("link not found");
2988         }
2989
2990         tipc_node_lock(node);
2991         link_reset_statistics(l_ptr);
2992         tipc_node_unlock(node);
2993         read_unlock_bh(&tipc_net_lock);
2994         return tipc_cfg_reply_none();
2995 }
2996
2997 /**
2998  * percent - convert count to a percentage of total (rounding up or down)
2999  */
3000
3001 static u32 percent(u32 count, u32 total)
3002 {
3003         return (count * 100 + (total / 2)) / total;
3004 }
3005
3006 /**
3007  * tipc_link_stats - print link statistics
3008  * @name: link name
3009  * @buf: print buffer area
3010  * @buf_size: size of print buffer area
3011  *
3012  * Returns length of print buffer data string (or 0 if error)
3013  */
3014
3015 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
3016 {
3017         struct print_buf pb;
3018         struct link *l_ptr;
3019         struct node *node;
3020         char *status;
3021         u32 profile_total = 0;
3022
3023         if (!strcmp(name, tipc_bclink_name))
3024                 return tipc_bclink_stats(buf, buf_size);
3025
3026         tipc_printbuf_init(&pb, buf, buf_size);
3027
3028         read_lock_bh(&tipc_net_lock);
3029         l_ptr = link_find_link(name, &node);
3030         if (!l_ptr) {
3031                 read_unlock_bh(&tipc_net_lock);
3032                 return 0;
3033         }
3034         tipc_node_lock(node);
3035
3036         if (tipc_link_is_active(l_ptr))
3037                 status = "ACTIVE";
3038         else if (tipc_link_is_up(l_ptr))
3039                 status = "STANDBY";
3040         else
3041                 status = "DEFUNCT";
3042         tipc_printf(&pb, "Link <%s>\n"
3043                          "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
3044                          "  Window:%u packets\n",
3045                     l_ptr->name, status, link_max_pkt(l_ptr),
3046                     l_ptr->priority, l_ptr->tolerance, l_ptr->queue_limit[0]);
3047         tipc_printf(&pb, "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
3048                     l_ptr->next_in_no - l_ptr->stats.recv_info,
3049                     l_ptr->stats.recv_fragments,
3050                     l_ptr->stats.recv_fragmented,
3051                     l_ptr->stats.recv_bundles,
3052                     l_ptr->stats.recv_bundled);
3053         tipc_printf(&pb, "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
3054                     l_ptr->next_out_no - l_ptr->stats.sent_info,
3055                     l_ptr->stats.sent_fragments,
3056                     l_ptr->stats.sent_fragmented,
3057                     l_ptr->stats.sent_bundles,
3058                     l_ptr->stats.sent_bundled);
3059         profile_total = l_ptr->stats.msg_length_counts;
3060         if (!profile_total)
3061                 profile_total = 1;
3062         tipc_printf(&pb, "  TX profile sample:%u packets  average:%u octets\n"
3063                          "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
3064                          "-16354:%u%% -32768:%u%% -66000:%u%%\n",
3065                     l_ptr->stats.msg_length_counts,
3066                     l_ptr->stats.msg_lengths_total / profile_total,
3067                     percent(l_ptr->stats.msg_length_profile[0], profile_total),
3068                     percent(l_ptr->stats.msg_length_profile[1], profile_total),
3069                     percent(l_ptr->stats.msg_length_profile[2], profile_total),
3070                     percent(l_ptr->stats.msg_length_profile[3], profile_total),
3071                     percent(l_ptr->stats.msg_length_profile[4], profile_total),
3072                     percent(l_ptr->stats.msg_length_profile[5], profile_total),
3073                     percent(l_ptr->stats.msg_length_profile[6], profile_total));
3074         tipc_printf(&pb, "  RX states:%u probes:%u naks:%u defs:%u dups:%u\n",
3075                     l_ptr->stats.recv_states,
3076                     l_ptr->stats.recv_probes,
3077                     l_ptr->stats.recv_nacks,
3078                     l_ptr->stats.deferred_recv,
3079                     l_ptr->stats.duplicates);
3080         tipc_printf(&pb, "  TX states:%u probes:%u naks:%u acks:%u dups:%u\n",
3081                     l_ptr->stats.sent_states,
3082                     l_ptr->stats.sent_probes,
3083                     l_ptr->stats.sent_nacks,
3084                     l_ptr->stats.sent_acks,
3085                     l_ptr->stats.retransmitted);
3086         tipc_printf(&pb, "  Congestion bearer:%u link:%u  Send queue max:%u avg:%u\n",
3087                     l_ptr->stats.bearer_congs,
3088                     l_ptr->stats.link_congs,
3089                     l_ptr->stats.max_queue_sz,
3090                     l_ptr->stats.queue_sz_counts
3091                     ? (l_ptr->stats.accu_queue_sz / l_ptr->stats.queue_sz_counts)
3092                     : 0);
3093
3094         tipc_node_unlock(node);
3095         read_unlock_bh(&tipc_net_lock);
3096         return tipc_printbuf_validate(&pb);
3097 }
3098
3099 #define MAX_LINK_STATS_INFO 2000
3100
3101 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
3102 {
3103         struct sk_buff *buf;
3104         struct tlv_desc *rep_tlv;
3105         int str_len;
3106
3107         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
3108                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
3109
3110         buf = tipc_cfg_reply_alloc(TLV_SPACE(MAX_LINK_STATS_INFO));
3111         if (!buf)
3112                 return NULL;
3113
3114         rep_tlv = (struct tlv_desc *)buf->data;
3115
3116         str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
3117                                   (char *)TLV_DATA(rep_tlv), MAX_LINK_STATS_INFO);
3118         if (!str_len) {
3119                 buf_discard(buf);
3120                 return tipc_cfg_reply_error_string("link not found");
3121         }
3122
3123         skb_put(buf, TLV_SPACE(str_len));
3124         TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
3125
3126         return buf;
3127 }
3128
3129 #if 0
3130 int link_control(const char *name, u32 op, u32 val)
3131 {
3132         int res = -EINVAL;
3133         struct link *l_ptr;
3134         u32 bearer_id;
3135         struct node * node;
3136         u32 a;
3137
3138         a = link_name2addr(name, &bearer_id);
3139         read_lock_bh(&tipc_net_lock);
3140         node = tipc_node_find(a);
3141         if (node) {
3142                 tipc_node_lock(node);
3143                 l_ptr = node->links[bearer_id];
3144                 if (l_ptr) {
3145                         if (op == TIPC_REMOVE_LINK) {
3146                                 struct bearer *b_ptr = l_ptr->b_ptr;
3147                                 spin_lock_bh(&b_ptr->publ.lock);
3148                                 tipc_link_delete(l_ptr);
3149                                 spin_unlock_bh(&b_ptr->publ.lock);
3150                         }
3151                         if (op == TIPC_CMD_BLOCK_LINK) {
3152                                 tipc_link_reset(l_ptr);
3153                                 l_ptr->blocked = 1;
3154                         }
3155                         if (op == TIPC_CMD_UNBLOCK_LINK) {
3156                                 l_ptr->blocked = 0;
3157                         }
3158                         res = TIPC_OK;
3159                 }
3160                 tipc_node_unlock(node);
3161         }
3162         read_unlock_bh(&tipc_net_lock);
3163         return res;
3164 }
3165 #endif
3166
3167 /**
3168  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
3169  * @dest: network address of destination node
3170  * @selector: used to select from set of active links
3171  *
3172  * If no active link can be found, uses default maximum packet size.
3173  */
3174
3175 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
3176 {
3177         struct node *n_ptr;
3178         struct link *l_ptr;
3179         u32 res = MAX_PKT_DEFAULT;
3180
3181         if (dest == tipc_own_addr)
3182                 return MAX_MSG_SIZE;
3183
3184         read_lock_bh(&tipc_net_lock);
3185         n_ptr = tipc_node_select(dest, selector);
3186         if (n_ptr) {
3187                 tipc_node_lock(n_ptr);
3188                 l_ptr = n_ptr->active_links[selector & 1];
3189                 if (l_ptr)
3190                         res = link_max_pkt(l_ptr);
3191                 tipc_node_unlock(n_ptr);
3192         }
3193         read_unlock_bh(&tipc_net_lock);
3194         return res;
3195 }
3196
3197 #if 0
3198 static void link_dump_rec_queue(struct link *l_ptr)
3199 {
3200         struct sk_buff *crs;
3201
3202         if (!l_ptr->oldest_deferred_in) {
3203                 info("Reception queue empty\n");
3204                 return;
3205         }
3206         info("Contents of Reception queue:\n");
3207         crs = l_ptr->oldest_deferred_in;
3208         while (crs) {
3209                 if (crs->data == (void *)0x0000a3a3) {
3210                         info("buffer %x invalid\n", crs);
3211                         return;
3212                 }
3213                 msg_dbg(buf_msg(crs), "In rec queue: \n");
3214                 crs = crs->next;
3215         }
3216 }
3217 #endif
3218
3219 static void link_dump_send_queue(struct link *l_ptr)
3220 {
3221         if (l_ptr->next_out) {
3222                 info("\nContents of unsent queue:\n");
3223                 dbg_print_buf_chain(l_ptr->next_out);
3224         }
3225         info("\nContents of send queue:\n");
3226         if (l_ptr->first_out) {
3227                 dbg_print_buf_chain(l_ptr->first_out);
3228         }
3229         info("Empty send queue\n");
3230 }
3231
3232 static void link_print(struct link *l_ptr, struct print_buf *buf,
3233                        const char *str)
3234 {
3235         tipc_printf(buf, str);
3236         if (link_reset_reset(l_ptr) || link_reset_unknown(l_ptr))
3237                 return;
3238         tipc_printf(buf, "Link %x<%s>:",
3239                     l_ptr->addr, l_ptr->b_ptr->publ.name);
3240         tipc_printf(buf, ": NXO(%u):", mod(l_ptr->next_out_no));
3241         tipc_printf(buf, "NXI(%u):", mod(l_ptr->next_in_no));
3242         tipc_printf(buf, "SQUE");
3243         if (l_ptr->first_out) {
3244                 tipc_printf(buf, "[%u..", msg_seqno(buf_msg(l_ptr->first_out)));
3245                 if (l_ptr->next_out)
3246                         tipc_printf(buf, "%u..",
3247                                     msg_seqno(buf_msg(l_ptr->next_out)));
3248                 tipc_printf(buf, "%u]",
3249                             msg_seqno(buf_msg
3250                                       (l_ptr->last_out)), l_ptr->out_queue_size);
3251                 if ((mod(msg_seqno(buf_msg(l_ptr->last_out)) -
3252                          msg_seqno(buf_msg(l_ptr->first_out)))
3253                      != (l_ptr->out_queue_size - 1))
3254                     || (l_ptr->last_out->next != NULL)) {
3255                         tipc_printf(buf, "\nSend queue inconsistency\n");
3256                         tipc_printf(buf, "first_out= %x ", l_ptr->first_out);
3257                         tipc_printf(buf, "next_out= %x ", l_ptr->next_out);
3258                         tipc_printf(buf, "last_out= %x ", l_ptr->last_out);
3259                         link_dump_send_queue(l_ptr);
3260                 }
3261         } else
3262                 tipc_printf(buf, "[]");
3263         tipc_printf(buf, "SQSIZ(%u)", l_ptr->out_queue_size);
3264         if (l_ptr->oldest_deferred_in) {
3265                 u32 o = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
3266                 u32 n = msg_seqno(buf_msg(l_ptr->newest_deferred_in));
3267                 tipc_printf(buf, ":RQUE[%u..%u]", o, n);
3268                 if (l_ptr->deferred_inqueue_sz != mod((n + 1) - o)) {
3269                         tipc_printf(buf, ":RQSIZ(%u)",
3270                                     l_ptr->deferred_inqueue_sz);
3271                 }
3272         }
3273         if (link_working_unknown(l_ptr))
3274                 tipc_printf(buf, ":WU");
3275         if (link_reset_reset(l_ptr))
3276                 tipc_printf(buf, ":RR");
3277         if (link_reset_unknown(l_ptr))
3278                 tipc_printf(buf, ":RU");
3279         if (link_working_working(l_ptr))
3280                 tipc_printf(buf, ":WW");
3281         tipc_printf(buf, "\n");
3282 }
3283