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   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  * Out-of-range value for link session numbers
  55  */
  56
  57 #define INVALID_SESSION 0x10000
  58
  59 /*
  60  * Limit for deferred reception queue:
  61  */
  62
  63 #define DEF_QUEUE_LIMIT 256u
  64
  65 /*
  66  * Link state events:
  67  */
  68
  69 #define  STARTING_EVT    856384768      /* link processing trigger */
  70 #define  TRAFFIC_MSG_EVT 560815u        /* rx'd ??? */
  71 #define  TIMEOUT_EVT     560817u        /* link timer expired */
  72
  73 /*
  74  * The following two 'message types' is really just implementation
  75  * data conveniently stored in the message header.
  76  * They must not be considered part of the protocol
  77  */
  78 #define OPEN_MSG   0
  79 #define CLOSED_MSG 1
  80
  81 /*
  82  * State value stored in 'exp_msg_count'
  83  */
  84
  85 #define START_CHANGEOVER 100000u
  86
  87 /**
  88  * struct link_name - deconstructed link name
  89  * @addr_local: network address of node at this end
  90  * @if_local: name of interface at this end
  91  * @addr_peer: network address of node at far end
  92  * @if_peer: name of interface at far end
  93  */
  94
  95 struct link_name {
  96         u32 addr_local;
  97         char if_local[TIPC_MAX_IF_NAME];
  98         u32 addr_peer;
  99         char if_peer[TIPC_MAX_IF_NAME];
 100 };
 101
 102 #if 0
 103
 104 /* LINK EVENT CODE IS NOT SUPPORTED AT PRESENT */
 105
 106 /**
 107  * struct link_event - link up/down event notification
 108  */
 109
 110 struct link_event {
 111         u32 addr;
 112         int up;
 113         void (*fcn)(u32, char *, int);
 114         char name[TIPC_MAX_LINK_NAME];
 115 };
 116
 117 #endif
 118
 119 static void link_handle_out_of_seq_msg(struct link *l_ptr,
 120                                        struct sk_buff *buf);
 121 static void link_recv_proto_msg(struct link *l_ptr, struct sk_buff *buf);
 122 static int  link_recv_changeover_msg(struct link **l_ptr, struct sk_buff **buf);
 123 static void link_set_supervision_props(struct link *l_ptr, u32 tolerance);
 124 static int  link_send_sections_long(struct port *sender,
 125                                     struct iovec const *msg_sect,
 126                                     u32 num_sect, u32 destnode);
 127 static void link_check_defragm_bufs(struct link *l_ptr);
 128 static void link_state_event(struct link *l_ptr, u32 event);
 129 static void link_reset_statistics(struct link *l_ptr);
 130 static void link_print(struct link *l_ptr, struct print_buf *buf,
 131                        const char *str);
 132
 133 /*
 134  * Debugging code used by link routines only
 135  *
 136  * When debugging link problems on a system that has multiple links,
 137  * the standard TIPC debugging routines may not be useful since they
 138  * allow the output from multiple links to be intermixed.  For this reason
 139  * routines of the form "dbg_link_XXX()" have been created that will capture
 140  * debug info into a link's personal print buffer, which can then be dumped
 141  * into the TIPC system log (TIPC_LOG) upon request.
 142  *
 143  * To enable per-link debugging, use LINK_LOG_BUF_SIZE to specify the size
 144  * of the print buffer used by each link.  If LINK_LOG_BUF_SIZE is set to 0,
 145  * the dbg_link_XXX() routines simply send their output to the standard
 146  * debug print buffer (DBG_OUTPUT), if it has been defined; this can be useful
 147  * when there is only a single link in the system being debugged.
 148  *
 149  * Notes:
 150  * - When enabled, LINK_LOG_BUF_SIZE should be set to at least TIPC_PB_MIN_SIZE
 151  * - "l_ptr" must be valid when using dbg_link_XXX() macros
 152  */
 153
 154 #define LINK_LOG_BUF_SIZE 0
 155
 156 #define dbg_link(fmt, arg...) \
 157         do { \
 158                 if (LINK_LOG_BUF_SIZE) \
 159                         tipc_printf(&l_ptr->print_buf, fmt, ## arg); \
 160         } while (0)
 161 #define dbg_link_msg(msg, txt) \
 162         do { \
 163                 if (LINK_LOG_BUF_SIZE) \
 164                         tipc_msg_dbg(&l_ptr->print_buf, msg, txt); \
 165         } while (0)
 166 #define dbg_link_state(txt) \
 167         do { \
 168                 if (LINK_LOG_BUF_SIZE) \
 169                         link_print(l_ptr, &l_ptr->print_buf, txt); \
 170         } while (0)
 171 #define dbg_link_dump() do { \
 172         if (LINK_LOG_BUF_SIZE) { \
 173                 tipc_printf(LOG, "\n\nDumping link <%s>:\n", l_ptr->name); \
 174                 tipc_printbuf_move(LOG, &l_ptr->print_buf); \
 175         } \
 176 } while (0)
 177
 178 static void dbg_print_link(struct link *l_ptr, const char *str)
 179 {
 180         if (DBG_OUTPUT != TIPC_NULL)
 181                 link_print(l_ptr, DBG_OUTPUT, str);
 182 }
 183
 184 static void dbg_print_buf_chain(struct sk_buff *root_buf)
 185 {
 186         if (DBG_OUTPUT != TIPC_NULL) {
 187                 struct sk_buff *buf = root_buf;
 188
 189                 while (buf) {
 190                         msg_dbg(buf_msg(buf), "In chain: ");
 191                         buf = buf->next;
 192                 }
 193         }
 194 }
 195
 196 /*
 197  *  Simple link routines
 198  */
 199
 200 static unsigned int align(unsigned int i)
 201 {
 202         return (i + 3) & ~3u;
 203 }
 204
 205 static void link_init_max_pkt(struct link *l_ptr)
 206 {
 207         u32 max_pkt;
 208
 209         max_pkt = (l_ptr->b_ptr->publ.mtu & ~3);
 210         if (max_pkt > MAX_MSG_SIZE)
 211                 max_pkt = MAX_MSG_SIZE;
 212
 213         l_ptr->max_pkt_target = max_pkt;
 214         if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
 215                 l_ptr->max_pkt = l_ptr->max_pkt_target;
 216         else
 217                 l_ptr->max_pkt = MAX_PKT_DEFAULT;
 218
 219         l_ptr->max_pkt_probes = 0;
 220 }
 221
 222 static u32 link_next_sent(struct link *l_ptr)
 223 {
 224         if (l_ptr->next_out)
 225                 return msg_seqno(buf_msg(l_ptr->next_out));
 226         return mod(l_ptr->next_out_no);
 227 }
 228
 229 static u32 link_last_sent(struct link *l_ptr)
 230 {
 231         return mod(link_next_sent(l_ptr) - 1);
 232 }
 233
 234 /*
 235  *  Simple non-static link routines (i.e. referenced outside this file)
 236  */
 237
 238 int tipc_link_is_up(struct link *l_ptr)
 239 {
 240         if (!l_ptr)
 241                 return 0;
 242         return (link_working_working(l_ptr) || link_working_unknown(l_ptr));
 243 }
 244
 245 int tipc_link_is_active(struct link *l_ptr)
 246 {
 247         return ((l_ptr->owner->active_links[0] == l_ptr) ||
 248                 (l_ptr->owner->active_links[1] == l_ptr));
 249 }
 250
 251 /**
 252  * link_name_validate - validate & (optionally) deconstruct link name
 253  * @name - ptr to link name string
 254  * @name_parts - ptr to area for link name components (or NULL if not needed)
 255  *
 256  * Returns 1 if link name is valid, otherwise 0.
 257  */
 258
 259 static int link_name_validate(const char *name, struct link_name *name_parts)
 260 {
 261         char name_copy[TIPC_MAX_LINK_NAME];
 262         char *addr_local;
 263         char *if_local;
 264         char *addr_peer;
 265         char *if_peer;
 266         char dummy;
 267         u32 z_local, c_local, n_local;
 268         u32 z_peer, c_peer, n_peer;
 269         u32 if_local_len;
 270         u32 if_peer_len;
 271
 272         /* copy link name & ensure length is OK */
 273
 274         name_copy[TIPC_MAX_LINK_NAME - 1] = 0;
 275         /* need above in case non-Posix strncpy() doesn't pad with nulls */
 276         strncpy(name_copy, name, TIPC_MAX_LINK_NAME);
 277         if (name_copy[TIPC_MAX_LINK_NAME - 1] != 0)
 278                 return 0;
 279
 280         /* ensure all component parts of link name are present */
 281
 282         addr_local = name_copy;
 283         if ((if_local = strchr(addr_local, ':')) == NULL)
 284                 return 0;
 285         *(if_local++) = 0;
 286         if ((addr_peer = strchr(if_local, '-')) == NULL)
 287                 return 0;
 288         *(addr_peer++) = 0;
 289         if_local_len = addr_peer - if_local;
 290         if ((if_peer = strchr(addr_peer, ':')) == NULL)
 291                 return 0;
 292         *(if_peer++) = 0;
 293         if_peer_len = strlen(if_peer) + 1;
 294
 295         /* validate component parts of link name */
 296
 297         if ((sscanf(addr_local, "%u.%u.%u%c",
 298                     &z_local, &c_local, &n_local, &dummy) != 3) ||
 299             (sscanf(addr_peer, "%u.%u.%u%c",
 300                     &z_peer, &c_peer, &n_peer, &dummy) != 3) ||
 301             (z_local > 255) || (c_local > 4095) || (n_local > 4095) ||
 302             (z_peer  > 255) || (c_peer  > 4095) || (n_peer  > 4095) ||
 303             (if_local_len <= 1) || (if_local_len > TIPC_MAX_IF_NAME) ||
 304             (if_peer_len  <= 1) || (if_peer_len  > TIPC_MAX_IF_NAME) ||
 305             (strspn(if_local, tipc_alphabet) != (if_local_len - 1)) ||
 306             (strspn(if_peer, tipc_alphabet) != (if_peer_len - 1)))
 307                 return 0;
 308
 309         /* return link name components, if necessary */
 310
 311         if (name_parts) {
 312                 name_parts->addr_local = tipc_addr(z_local, c_local, n_local);
 313                 strcpy(name_parts->if_local, if_local);
 314                 name_parts->addr_peer = tipc_addr(z_peer, c_peer, n_peer);
 315                 strcpy(name_parts->if_peer, if_peer);
 316         }
 317         return 1;
 318 }
 319
 320 /**
 321  * link_timeout - handle expiration of link timer
 322  * @l_ptr: pointer to link
 323  *
 324  * This routine must not grab "tipc_net_lock" to avoid a potential deadlock conflict
 325  * with tipc_link_delete().  (There is no risk that the node will be deleted by
 326  * another thread because tipc_link_delete() always cancels the link timer before
 327  * tipc_node_delete() is called.)
 328  */
 329
 330 static void link_timeout(struct link *l_ptr)
 331 {
 332         tipc_node_lock(l_ptr->owner);
 333
 334         /* update counters used in statistical profiling of send traffic */
 335
 336         l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
 337         l_ptr->stats.queue_sz_counts++;
 338
 339         if (l_ptr->out_queue_size > l_ptr->stats.max_queue_sz)
 340                 l_ptr->stats.max_queue_sz = l_ptr->out_queue_size;
 341
 342         if (l_ptr->first_out) {
 343                 struct tipc_msg *msg = buf_msg(l_ptr->first_out);
 344                 u32 length = msg_size(msg);
 345
 346                 if ((msg_user(msg) == MSG_FRAGMENTER) &&
 347                     (msg_type(msg) == FIRST_FRAGMENT)) {
 348                         length = msg_size(msg_get_wrapped(msg));
 349                 }
 350                 if (length) {
 351                         l_ptr->stats.msg_lengths_total += length;
 352                         l_ptr->stats.msg_length_counts++;
 353                         if (length <= 64)
 354                                 l_ptr->stats.msg_length_profile[0]++;
 355                         else if (length <= 256)
 356                                 l_ptr->stats.msg_length_profile[1]++;
 357                         else if (length <= 1024)
 358                                 l_ptr->stats.msg_length_profile[2]++;
 359                         else if (length <= 4096)
 360                                 l_ptr->stats.msg_length_profile[3]++;
 361                         else if (length <= 16384)
 362                                 l_ptr->stats.msg_length_profile[4]++;
 363                         else if (length <= 32768)
 364                                 l_ptr->stats.msg_length_profile[5]++;
 365                         else
 366                                 l_ptr->stats.msg_length_profile[6]++;
 367                 }
 368         }
 369
 370         /* do all other link processing performed on a periodic basis */
 371
 372         link_check_defragm_bufs(l_ptr);
 373
 374         link_state_event(l_ptr, TIMEOUT_EVT);
 375
 376         if (l_ptr->next_out)
 377                 tipc_link_push_queue(l_ptr);
 378
 379         tipc_node_unlock(l_ptr->owner);
 380 }
 381
 382 static void link_set_timer(struct link *l_ptr, u32 time)
 383 {
 384         k_start_timer(&l_ptr->timer, time);
 385 }
 386
 387 /**
 388  * tipc_link_create - create a new link
 389  * @b_ptr: pointer to associated bearer
 390  * @peer: network address of node at other end of link
 391  * @media_addr: media address to use when sending messages over link
 392  *
 393  * Returns pointer to link.
 394  */
 395
 396 struct link *tipc_link_create(struct bearer *b_ptr, const u32 peer,
 397                               const struct tipc_media_addr *media_addr)
 398 {
 399         struct link *l_ptr;
 400         struct tipc_msg *msg;
 401         char *if_name;
 402
 403         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 404         if (!l_ptr) {
 405                 warn("Link creation failed, no memory\n");
 406                 return NULL;
 407         }
 408
 409         if (LINK_LOG_BUF_SIZE) {
 410                 char *pb = kmalloc(LINK_LOG_BUF_SIZE, GFP_ATOMIC);
 411
 412                 if (!pb) {
 413                         kfree(l_ptr);
 414                         warn("Link creation failed, no memory for print buffer\n");
 415                         return NULL;
 416                 }
 417                 tipc_printbuf_init(&l_ptr->print_buf, pb, LINK_LOG_BUF_SIZE);
 418         }
 419
 420         l_ptr->addr = peer;
 421         if_name = strchr(b_ptr->publ.name, ':') + 1;
 422         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:",
 423                 tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
 424                 tipc_node(tipc_own_addr),
 425                 if_name,
 426                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 427                 /* note: peer i/f is appended to link name by reset/activate */
 428         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 429         l_ptr->checkpoint = 1;
 430         l_ptr->b_ptr = b_ptr;
 431         link_set_supervision_props(l_ptr, b_ptr->media->tolerance);
 432         l_ptr->state = RESET_UNKNOWN;
 433
 434         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 435         msg = l_ptr->pmsg;
 436         tipc_msg_init(msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, l_ptr->addr);
 437         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 438         msg_set_session(msg, (tipc_random & 0xffff));
 439         msg_set_bearer_id(msg, b_ptr->identity);
 440         strcpy((char *)msg_data(msg), if_name);
 441
 442         l_ptr->priority = b_ptr->priority;
 443         tipc_link_set_queue_limits(l_ptr, b_ptr->media->window);
 444
 445         link_init_max_pkt(l_ptr);
 446
 447         l_ptr->next_out_no = 1;
 448         INIT_LIST_HEAD(&l_ptr->waiting_ports);
 449
 450         link_reset_statistics(l_ptr);
 451
 452         l_ptr->owner = tipc_node_attach_link(l_ptr);
 453         if (!l_ptr->owner) {
 454                 if (LINK_LOG_BUF_SIZE)
 455                         kfree(l_ptr->print_buf.buf);
 456                 kfree(l_ptr);
 457                 return NULL;
 458         }
 459
 460         k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
 461         list_add_tail(&l_ptr->link_list, &b_ptr->links);
 462         tipc_k_signal((Handler)tipc_link_start, (unsigned long)l_ptr);
 463
 464         dbg("tipc_link_create(): tolerance = %u,cont intv = %u, abort_limit = %u\n",
 465             l_ptr->tolerance, l_ptr->continuity_interval, l_ptr->abort_limit);
 466
 467         return l_ptr;
 468 }
 469
 470 /**
 471  * tipc_link_delete - delete a link
 472  * @l_ptr: pointer to link
 473  *
 474  * Note: 'tipc_net_lock' is write_locked, bearer is locked.
 475  * This routine must not grab the node lock until after link timer cancellation
 476  * to avoid a potential deadlock situation.
 477  */
 478
 479 void tipc_link_delete(struct link *l_ptr)
 480 {
 481         if (!l_ptr) {
 482                 err("Attempt to delete non-existent link\n");
 483                 return;
 484         }
 485
 486         dbg("tipc_link_delete()\n");
 487
 488         k_cancel_timer(&l_ptr->timer);
 489
 490         tipc_node_lock(l_ptr->owner);
 491         tipc_link_reset(l_ptr);
 492         tipc_node_detach_link(l_ptr->owner, l_ptr);
 493         tipc_link_stop(l_ptr);
 494         list_del_init(&l_ptr->link_list);
 495         if (LINK_LOG_BUF_SIZE)
 496                 kfree(l_ptr->print_buf.buf);
 497         tipc_node_unlock(l_ptr->owner);
 498         k_term_timer(&l_ptr->timer);
 499         kfree(l_ptr);
 500 }
 501
 502 void tipc_link_start(struct link *l_ptr)
 503 {
 504         dbg("tipc_link_start %x\n", l_ptr);
 505         link_state_event(l_ptr, STARTING_EVT);
 506 }
 507
 508 /**
 509  * link_schedule_port - schedule port for deferred sending
 510  * @l_ptr: pointer to link
 511  * @origport: reference to sending port
 512  * @sz: amount of data to be sent
 513  *
 514  * Schedules port for renewed sending of messages after link congestion
 515  * has abated.
 516  */
 517
 518 static int link_schedule_port(struct link *l_ptr, u32 origport, u32 sz)
 519 {
 520         struct port *p_ptr;
 521
 522         spin_lock_bh(&tipc_port_list_lock);
 523         p_ptr = tipc_port_lock(origport);
 524         if (p_ptr) {
 525                 if (!p_ptr->wakeup)
 526                         goto exit;
 527                 if (!list_empty(&p_ptr->wait_list))
 528                         goto exit;
 529                 p_ptr->publ.congested = 1;
 530                 p_ptr->waiting_pkts = 1 + ((sz - 1) / l_ptr->max_pkt);
 531                 list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
 532                 l_ptr->stats.link_congs++;
 533 exit:
 534                 tipc_port_unlock(p_ptr);
 535         }
 536         spin_unlock_bh(&tipc_port_list_lock);
 537         return -ELINKCONG;
 538 }
 539
 540 void tipc_link_wakeup_ports(struct link *l_ptr, int all)
 541 {
 542         struct port *p_ptr;
 543         struct port *temp_p_ptr;
 544         int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;
 545
 546         if (all)
 547                 win = 100000;
 548         if (win <= 0)
 549                 return;
 550         if (!spin_trylock_bh(&tipc_port_list_lock))
 551                 return;
 552         if (link_congested(l_ptr))
 553                 goto exit;
 554         list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
 555                                  wait_list) {
 556                 if (win <= 0)
 557                         break;
 558                 list_del_init(&p_ptr->wait_list);
 559                 spin_lock_bh(p_ptr->publ.lock);
 560                 p_ptr->publ.congested = 0;
 561                 p_ptr->wakeup(&p_ptr->publ);
 562                 win -= p_ptr->waiting_pkts;
 563                 spin_unlock_bh(p_ptr->publ.lock);
 564         }
 565
 566 exit:
 567         spin_unlock_bh(&tipc_port_list_lock);
 568 }
 569
 570 /**
 571  * link_release_outqueue - purge link's outbound message queue
 572  * @l_ptr: pointer to link
 573  */
 574
 575 static void link_release_outqueue(struct link *l_ptr)
 576 {
 577         struct sk_buff *buf = l_ptr->first_out;
 578         struct sk_buff *next;
 579
 580         while (buf) {
 581                 next = buf->next;
 582                 buf_discard(buf);
 583                 buf = next;
 584         }
 585         l_ptr->first_out = NULL;
 586         l_ptr->out_queue_size = 0;
 587 }
 588
 589 /**
 590  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 591  * @l_ptr: pointer to link
 592  */
 593
 594 void tipc_link_reset_fragments(struct link *l_ptr)
 595 {
 596         struct sk_buff *buf = l_ptr->defragm_buf;
 597         struct sk_buff *next;
 598
 599         while (buf) {
 600                 next = buf->next;
 601                 buf_discard(buf);
 602                 buf = next;
 603         }
 604         l_ptr->defragm_buf = NULL;
 605 }
 606
 607 /**
 608  * tipc_link_stop - purge all inbound and outbound messages associated with link
 609  * @l_ptr: pointer to link
 610  */
 611
 612 void tipc_link_stop(struct link *l_ptr)
 613 {
 614         struct sk_buff *buf;
 615         struct sk_buff *next;
 616
 617         buf = l_ptr->oldest_deferred_in;
 618         while (buf) {
 619                 next = buf->next;
 620                 buf_discard(buf);
 621                 buf = next;
 622         }
 623
 624         buf = l_ptr->first_out;
 625         while (buf) {
 626                 next = buf->next;
 627                 buf_discard(buf);
 628                 buf = next;
 629         }
 630
 631         tipc_link_reset_fragments(l_ptr);
 632
 633         buf_discard(l_ptr->proto_msg_queue);
 634         l_ptr->proto_msg_queue = NULL;
 635 }
 636
 637 #if 0
 638
 639 /* LINK EVENT CODE IS NOT SUPPORTED AT PRESENT */
 640
 641 static void link_recv_event(struct link_event *ev)
 642 {
 643         ev->fcn(ev->addr, ev->name, ev->up);
 644         kfree(ev);
 645 }
 646
 647 static void link_send_event(void (*fcn)(u32 a, char *n, int up),
 648                             struct link *l_ptr, int up)
 649 {
 650         struct link_event *ev;
 651
 652         ev = kmalloc(sizeof(*ev), GFP_ATOMIC);
 653         if (!ev) {
 654                 warn("Link event allocation failure\n");
 655                 return;
 656         }
 657         ev->addr = l_ptr->addr;
 658         ev->up = up;
 659         ev->fcn = fcn;
 660         memcpy(ev->name, l_ptr->name, TIPC_MAX_LINK_NAME);
 661         tipc_k_signal((Handler)link_recv_event, (unsigned long)ev);
 662 }
 663
 664 #else
 665
 666 #define link_send_event(fcn, l_ptr, up) do { } while (0)
 667
 668 #endif
 669
 670 void tipc_link_reset(struct link *l_ptr)
 671 {
 672         struct sk_buff *buf;
 673         u32 prev_state = l_ptr->state;
 674         u32 checkpoint = l_ptr->next_in_no;
 675         int was_active_link = tipc_link_is_active(l_ptr);
 676
 677         msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
 678
 679         /* Link is down, accept any session */
 680         l_ptr->peer_session = INVALID_SESSION;
 681
 682         /* Prepare for max packet size negotiation */
 683         link_init_max_pkt(l_ptr);
 684
 685         l_ptr->state = RESET_UNKNOWN;
 686         dbg_link_state("Resetting Link\n");
 687
 688         if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
 689                 return;
 690
 691         tipc_node_link_down(l_ptr->owner, l_ptr);
 692         tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
 693 #if 0
 694         tipc_printf(TIPC_CONS, "\nReset link <%s>\n", l_ptr->name);
 695         dbg_link_dump();
 696 #endif
 697         if (was_active_link && tipc_node_has_active_links(l_ptr->owner) &&
 698             l_ptr->owner->permit_changeover) {
 699                 l_ptr->reset_checkpoint = checkpoint;
 700                 l_ptr->exp_msg_count = START_CHANGEOVER;
 701         }
 702
 703         /* Clean up all queues: */
 704
 705         link_release_outqueue(l_ptr);
 706         buf_discard(l_ptr->proto_msg_queue);
 707         l_ptr->proto_msg_queue = NULL;
 708         buf = l_ptr->oldest_deferred_in;
 709         while (buf) {
 710                 struct sk_buff *next = buf->next;
 711                 buf_discard(buf);
 712                 buf = next;
 713         }
 714         if (!list_empty(&l_ptr->waiting_ports))
 715                 tipc_link_wakeup_ports(l_ptr, 1);
 716
 717         l_ptr->retransm_queue_head = 0;
 718         l_ptr->retransm_queue_size = 0;
 719         l_ptr->last_out = NULL;
 720         l_ptr->first_out = NULL;
 721         l_ptr->next_out = NULL;
 722         l_ptr->unacked_window = 0;
 723         l_ptr->checkpoint = 1;
 724         l_ptr->next_out_no = 1;
 725         l_ptr->deferred_inqueue_sz = 0;
 726         l_ptr->oldest_deferred_in = NULL;
 727         l_ptr->newest_deferred_in = NULL;
 728         l_ptr->fsm_msg_cnt = 0;
 729         l_ptr->stale_count = 0;
 730         link_reset_statistics(l_ptr);
 731
 732         link_send_event(tipc_cfg_link_event, l_ptr, 0);
 733         if (!in_own_cluster(l_ptr->addr))
 734                 link_send_event(tipc_disc_link_event, l_ptr, 0);
 735 }
 736
 737
 738 static void link_activate(struct link *l_ptr)
 739 {
 740         l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
 741         tipc_node_link_up(l_ptr->owner, l_ptr);
 742         tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
 743         link_send_event(tipc_cfg_link_event, l_ptr, 1);
 744         if (!in_own_cluster(l_ptr->addr))
 745                 link_send_event(tipc_disc_link_event, l_ptr, 1);
 746 }
 747
 748 /**
 749  * link_state_event - link finite state machine
 750  * @l_ptr: pointer to link
 751  * @event: state machine event to process
 752  */
 753
 754 static void link_state_event(struct link *l_ptr, unsigned event)
 755 {
 756         struct link *other;
 757         u32 cont_intv = l_ptr->continuity_interval;
 758
 759         if (!l_ptr->started && (event != STARTING_EVT))
 760                 return;         /* Not yet. */
 761
 762         if (link_blocked(l_ptr)) {
 763                 if (event == TIMEOUT_EVT) {
 764                         link_set_timer(l_ptr, cont_intv);
 765                 }
 766                 return;   /* Changeover going on */
 767         }
 768         dbg_link("STATE_EV: <%s> ", l_ptr->name);
 769
 770         switch (l_ptr->state) {
 771         case WORKING_WORKING:
 772                 dbg_link("WW/");
 773                 switch (event) {
 774                 case TRAFFIC_MSG_EVT:
 775                         dbg_link("TRF-");
 776                         /* fall through */
 777                 case ACTIVATE_MSG:
 778                         dbg_link("ACT\n");
 779                         break;
 780                 case TIMEOUT_EVT:
 781                         dbg_link("TIM ");
 782                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 783                                 l_ptr->checkpoint = l_ptr->next_in_no;
 784                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 785                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 786                                                                  0, 0, 0, 0, 0);
 787                                         l_ptr->fsm_msg_cnt++;
 788                                 } else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
 789                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 790                                                                  1, 0, 0, 0, 0);
 791                                         l_ptr->fsm_msg_cnt++;
 792                                 }
 793                                 link_set_timer(l_ptr, cont_intv);
 794                                 break;
 795                         }
 796                         dbg_link(" -> WU\n");
 797                         l_ptr->state = WORKING_UNKNOWN;
 798                         l_ptr->fsm_msg_cnt = 0;
 799                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 800                         l_ptr->fsm_msg_cnt++;
 801                         link_set_timer(l_ptr, cont_intv / 4);
 802                         break;
 803                 case RESET_MSG:
 804                         dbg_link("RES -> RR\n");
 805                         info("Resetting link <%s>, requested by peer\n",
 806                              l_ptr->name);
 807                         tipc_link_reset(l_ptr);
 808                         l_ptr->state = RESET_RESET;
 809                         l_ptr->fsm_msg_cnt = 0;
 810                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 811                         l_ptr->fsm_msg_cnt++;
 812                         link_set_timer(l_ptr, cont_intv);
 813                         break;
 814                 default:
 815                         err("Unknown link event %u in WW state\n", event);
 816                 }
 817                 break;
 818         case WORKING_UNKNOWN:
 819                 dbg_link("WU/");
 820                 switch (event) {
 821                 case TRAFFIC_MSG_EVT:
 822                         dbg_link("TRF-");
 823                 case ACTIVATE_MSG:
 824                         dbg_link("ACT -> WW\n");
 825                         l_ptr->state = WORKING_WORKING;
 826                         l_ptr->fsm_msg_cnt = 0;
 827                         link_set_timer(l_ptr, cont_intv);
 828                         break;
 829                 case RESET_MSG:
 830                         dbg_link("RES -> RR\n");
 831                         info("Resetting link <%s>, requested by peer "
 832                              "while probing\n", l_ptr->name);
 833                         tipc_link_reset(l_ptr);
 834                         l_ptr->state = RESET_RESET;
 835                         l_ptr->fsm_msg_cnt = 0;
 836                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 837                         l_ptr->fsm_msg_cnt++;
 838                         link_set_timer(l_ptr, cont_intv);
 839                         break;
 840                 case TIMEOUT_EVT:
 841                         dbg_link("TIM ");
 842                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 843                                 dbg_link("-> WW\n");
 844                                 l_ptr->state = WORKING_WORKING;
 845                                 l_ptr->fsm_msg_cnt = 0;
 846                                 l_ptr->checkpoint = l_ptr->next_in_no;
 847                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 848                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 849                                                                  0, 0, 0, 0, 0);
 850                                         l_ptr->fsm_msg_cnt++;
 851                                 }
 852                                 link_set_timer(l_ptr, cont_intv);
 853                         } else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
 854                                 dbg_link("Probing %u/%u,timer = %u ms)\n",
 855                                          l_ptr->fsm_msg_cnt, l_ptr->abort_limit,
 856                                          cont_intv / 4);
 857                                 tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 858                                                          1, 0, 0, 0, 0);
 859                                 l_ptr->fsm_msg_cnt++;
 860                                 link_set_timer(l_ptr, cont_intv / 4);
 861                         } else {        /* Link has failed */
 862                                 dbg_link("-> RU (%u probes unanswered)\n",
 863                                          l_ptr->fsm_msg_cnt);
 864                                 warn("Resetting link <%s>, peer not responding\n",
 865                                      l_ptr->name);
 866                                 tipc_link_reset(l_ptr);
 867                                 l_ptr->state = RESET_UNKNOWN;
 868                                 l_ptr->fsm_msg_cnt = 0;
 869                                 tipc_link_send_proto_msg(l_ptr, RESET_MSG,
 870                                                          0, 0, 0, 0, 0);
 871                                 l_ptr->fsm_msg_cnt++;
 872                                 link_set_timer(l_ptr, cont_intv);
 873                         }
 874                         break;
 875                 default:
 876                         err("Unknown link event %u in WU state\n", event);
 877                 }
 878                 break;
 879         case RESET_UNKNOWN:
 880                 dbg_link("RU/");
 881                 switch (event) {
 882                 case TRAFFIC_MSG_EVT:
 883                         dbg_link("TRF-\n");
 884                         break;
 885                 case ACTIVATE_MSG:
 886                         other = l_ptr->owner->active_links[0];
 887                         if (other && link_working_unknown(other)) {
 888                                 dbg_link("ACT\n");
 889                                 break;
 890                         }
 891                         dbg_link("ACT -> WW\n");
 892                         l_ptr->state = WORKING_WORKING;
 893                         l_ptr->fsm_msg_cnt = 0;
 894                         link_activate(l_ptr);
 895                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 896                         l_ptr->fsm_msg_cnt++;
 897                         link_set_timer(l_ptr, cont_intv);
 898                         break;
 899                 case RESET_MSG:
 900                         dbg_link("RES\n");
 901                         dbg_link(" -> RR\n");
 902                         l_ptr->state = RESET_RESET;
 903                         l_ptr->fsm_msg_cnt = 0;
 904                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
 905                         l_ptr->fsm_msg_cnt++;
 906                         link_set_timer(l_ptr, cont_intv);
 907                         break;
 908                 case STARTING_EVT:
 909                         dbg_link("START-");
 910                         l_ptr->started = 1;
 911                         /* fall through */
 912                 case TIMEOUT_EVT:
 913                         dbg_link("TIM\n");
 914                         tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
 915                         l_ptr->fsm_msg_cnt++;
 916                         link_set_timer(l_ptr, cont_intv);
 917                         break;
 918                 default:
 919                         err("Unknown link event %u in RU state\n", event);
 920                 }
 921                 break;
 922         case RESET_RESET:
 923                 dbg_link("RR/ ");
 924                 switch (event) {
 925                 case TRAFFIC_MSG_EVT:
 926                         dbg_link("TRF-");
 927                         /* fall through */
 928                 case ACTIVATE_MSG:
 929                         other = l_ptr->owner->active_links[0];
 930                         if (other && link_working_unknown(other)) {
 931                                 dbg_link("ACT\n");
 932                                 break;
 933                         }
 934                         dbg_link("ACT -> WW\n");
 935                         l_ptr->state = WORKING_WORKING;
 936                         l_ptr->fsm_msg_cnt = 0;
 937                         link_activate(l_ptr);
 938                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 939                         l_ptr->fsm_msg_cnt++;
 940                         link_set_timer(l_ptr, cont_intv);
 941                         break;
 942                 case RESET_MSG:
 943                         dbg_link("RES\n");
 944                         break;
 945                 case TIMEOUT_EVT:
 946                         dbg_link("TIM\n");
 947                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 948                         l_ptr->fsm_msg_cnt++;
 949                         link_set_timer(l_ptr, cont_intv);
 950                         dbg_link("fsm_msg_cnt %u\n", l_ptr->fsm_msg_cnt);
 951                         break;
 952                 default:
 953                         err("Unknown link event %u in RR state\n", event);
 954                 }
 955                 break;
 956         default:
 957                 err("Unknown link state %u/%u\n", l_ptr->state, event);
 958         }
 959 }
 960
 961 /*
 962  * link_bundle_buf(): Append contents of a buffer to
 963  * the tail of an existing one.
 964  */
 965
 966 static int link_bundle_buf(struct link *l_ptr,
 967                            struct sk_buff *bundler,
 968                            struct sk_buff *buf)
 969 {
 970         struct tipc_msg *bundler_msg = buf_msg(bundler);
 971         struct tipc_msg *msg = buf_msg(buf);
 972         u32 size = msg_size(msg);
 973         u32 bundle_size = msg_size(bundler_msg);
 974         u32 to_pos = align(bundle_size);
 975         u32 pad = to_pos - bundle_size;
 976
 977         if (msg_user(bundler_msg) != MSG_BUNDLER)
 978                 return 0;
 979         if (msg_type(bundler_msg) != OPEN_MSG)
 980                 return 0;
 981         if (skb_tailroom(bundler) < (pad + size))
 982                 return 0;
 983         if (l_ptr->max_pkt < (to_pos + size))
 984                 return 0;
 985
 986         skb_put(bundler, pad + size);
 987         skb_copy_to_linear_data_offset(bundler, to_pos, buf->data, size);
 988         msg_set_size(bundler_msg, to_pos + size);
 989         msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
 990         dbg("Packed msg # %u(%u octets) into pos %u in buf(#%u)\n",
 991             msg_msgcnt(bundler_msg), size, to_pos, msg_seqno(bundler_msg));
 992         msg_dbg(msg, "PACKD:");
 993         buf_discard(buf);
 994         l_ptr->stats.sent_bundled++;
 995         return 1;
 996 }
 997
 998 static void link_add_to_outqueue(struct link *l_ptr,
 999                                  struct sk_buff *buf,
1000                                  struct tipc_msg *msg)
1001 {
1002         u32 ack = mod(l_ptr->next_in_no - 1);
1003         u32 seqno = mod(l_ptr->next_out_no++);
1004
1005         msg_set_word(msg, 2, ((ack << 16) | seqno));
1006         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1007         buf->next = NULL;
1008         if (l_ptr->first_out) {
1009                 l_ptr->last_out->next = buf;
1010                 l_ptr->last_out = buf;
1011         } else
1012                 l_ptr->first_out = l_ptr->last_out = buf;
1013         l_ptr->out_queue_size++;
1014 }
1015
1016 /*
1017  * tipc_link_send_buf() is the 'full path' for messages, called from
1018  * inside TIPC when the 'fast path' in tipc_send_buf
1019  * has failed, and from link_send()
1020  */
1021
1022 int tipc_link_send_buf(struct link *l_ptr, struct sk_buff *buf)
1023 {
1024         struct tipc_msg *msg = buf_msg(buf);
1025         u32 size = msg_size(msg);
1026         u32 dsz = msg_data_sz(msg);
1027         u32 queue_size = l_ptr->out_queue_size;
1028         u32 imp = tipc_msg_tot_importance(msg);
1029         u32 queue_limit = l_ptr->queue_limit[imp];
1030         u32 max_packet = l_ptr->max_pkt;
1031
1032         msg_set_prevnode(msg, tipc_own_addr);   /* If routed message */
1033
1034         /* Match msg importance against queue limits: */
1035
1036         if (unlikely(queue_size >= queue_limit)) {
1037                 if (imp <= TIPC_CRITICAL_IMPORTANCE) {
1038                         return link_schedule_port(l_ptr, msg_origport(msg),
1039                                                   size);
1040                 }
1041                 msg_dbg(msg, "TIPC: Congestion, throwing away\n");
1042                 buf_discard(buf);
1043                 if (imp > CONN_MANAGER) {
1044                         warn("Resetting link <%s>, send queue full", l_ptr->name);
1045                         tipc_link_reset(l_ptr);
1046                 }
1047                 return dsz;
1048         }
1049
1050         /* Fragmentation needed ? */
1051
1052         if (size > max_packet)
1053                 return tipc_link_send_long_buf(l_ptr, buf);
1054
1055         /* Packet can be queued or sent: */
1056
1057         if (queue_size > l_ptr->stats.max_queue_sz)
1058                 l_ptr->stats.max_queue_sz = queue_size;
1059
1060         if (likely(!tipc_bearer_congested(l_ptr->b_ptr, l_ptr) &&
1061                    !link_congested(l_ptr))) {
1062                 link_add_to_outqueue(l_ptr, buf, msg);
1063
1064                 if (likely(tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr))) {
1065                         l_ptr->unacked_window = 0;
1066                 } else {
1067                         tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1068                         l_ptr->stats.bearer_congs++;
1069                         l_ptr->next_out = buf;
1070                 }
1071                 return dsz;
1072         }
1073         /* Congestion: can message be bundled ?: */
1074
1075         if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
1076             (msg_user(msg) != MSG_FRAGMENTER)) {
1077
1078                 /* Try adding message to an existing bundle */
1079
1080                 if (l_ptr->next_out &&
1081                     link_bundle_buf(l_ptr, l_ptr->last_out, buf)) {
1082                         tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
1083                         return dsz;
1084                 }
1085
1086                 /* Try creating a new bundle */
1087
1088                 if (size <= max_packet * 2 / 3) {
1089                         struct sk_buff *bundler = buf_acquire(max_packet);
1090                         struct tipc_msg bundler_hdr;
1091
1092                         if (bundler) {
1093                                 tipc_msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
1094                                          INT_H_SIZE, l_ptr->addr);
1095                                 skb_copy_to_linear_data(bundler, &bundler_hdr,
1096                                                         INT_H_SIZE);
1097                                 skb_trim(bundler, INT_H_SIZE);
1098                                 link_bundle_buf(l_ptr, bundler, buf);
1099                                 buf = bundler;
1100                                 msg = buf_msg(buf);
1101                                 l_ptr->stats.sent_bundles++;
1102                         }
1103                 }
1104         }
1105         if (!l_ptr->next_out)
1106                 l_ptr->next_out = buf;
1107         link_add_to_outqueue(l_ptr, buf, msg);
1108         tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
1109         return dsz;
1110 }
1111
1112 /*
1113  * tipc_link_send(): same as tipc_link_send_buf(), but the link to use has
1114  * not been selected yet, and the the owner node is not locked
1115  * Called by TIPC internal users, e.g. the name distributor
1116  */
1117
1118 int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector)
1119 {
1120         struct link *l_ptr;
1121         struct tipc_node *n_ptr;
1122         int res = -ELINKCONG;
1123
1124         read_lock_bh(&tipc_net_lock);
1125         n_ptr = tipc_node_select(dest, selector);
1126         if (n_ptr) {
1127                 tipc_node_lock(n_ptr);
1128                 l_ptr = n_ptr->active_links[selector & 1];
1129                 if (l_ptr) {
1130                         dbg("tipc_link_send: found link %x for dest %x\n", l_ptr, dest);
1131                         res = tipc_link_send_buf(l_ptr, buf);
1132                 } else {
1133                         dbg("Attempt to send msg to unreachable node:\n");
1134                         msg_dbg(buf_msg(buf),">>>");
1135                         buf_discard(buf);
1136                 }
1137                 tipc_node_unlock(n_ptr);
1138         } else {
1139                 dbg("Attempt to send msg to unknown node:\n");
1140                 msg_dbg(buf_msg(buf),">>>");
1141                 buf_discard(buf);
1142         }
1143         read_unlock_bh(&tipc_net_lock);
1144         return res;
1145 }
1146
1147 /*
1148  * link_send_buf_fast: Entry for data messages where the
1149  * destination link is known and the header is complete,
1150  * inclusive total message length. Very time critical.
1151  * Link is locked. Returns user data length.
1152  */
1153
1154 static int link_send_buf_fast(struct link *l_ptr, struct sk_buff *buf,
1155                               u32 *used_max_pkt)
1156 {
1157         struct tipc_msg *msg = buf_msg(buf);
1158         int res = msg_data_sz(msg);
1159
1160         if (likely(!link_congested(l_ptr))) {
1161                 if (likely(msg_size(msg) <= l_ptr->max_pkt)) {
1162                         if (likely(list_empty(&l_ptr->b_ptr->cong_links))) {
1163                                 link_add_to_outqueue(l_ptr, buf, msg);
1164                                 if (likely(tipc_bearer_send(l_ptr->b_ptr, buf,
1165                                                             &l_ptr->media_addr))) {
1166                                         l_ptr->unacked_window = 0;
1167                                         msg_dbg(msg,"SENT_FAST:");
1168                                         return res;
1169                                 }
1170                                 dbg("failed sent fast...\n");
1171                                 tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1172                                 l_ptr->stats.bearer_congs++;
1173                                 l_ptr->next_out = buf;
1174                                 return res;
1175                         }
1176                 }
1177                 else
1178                         *used_max_pkt = l_ptr->max_pkt;
1179         }
1180         return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
1181 }
1182
1183 /*
1184  * tipc_send_buf_fast: Entry for data messages where the
1185  * destination node is known and the header is complete,
1186  * inclusive total message length.
1187  * Returns user data length.
1188  */
1189 int tipc_send_buf_fast(struct sk_buff *buf, u32 destnode)
1190 {
1191         struct link *l_ptr;
1192         struct tipc_node *n_ptr;
1193         int res;
1194         u32 selector = msg_origport(buf_msg(buf)) & 1;
1195         u32 dummy;
1196
1197         if (destnode == tipc_own_addr)
1198                 return tipc_port_recv_msg(buf);
1199
1200         read_lock_bh(&tipc_net_lock);
1201         n_ptr = tipc_node_select(destnode, selector);
1202         if (likely(n_ptr)) {
1203                 tipc_node_lock(n_ptr);
1204                 l_ptr = n_ptr->active_links[selector];
1205                 dbg("send_fast: buf %x selected %x, destnode = %x\n",
1206                     buf, l_ptr, destnode);
1207                 if (likely(l_ptr)) {
1208                         res = link_send_buf_fast(l_ptr, buf, &dummy);
1209                         tipc_node_unlock(n_ptr);
1210                         read_unlock_bh(&tipc_net_lock);
1211                         return res;
1212                 }
1213                 tipc_node_unlock(n_ptr);
1214         }
1215         read_unlock_bh(&tipc_net_lock);
1216         res = msg_data_sz(buf_msg(buf));
1217         tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1218         return res;
1219 }
1220
1221
1222 /*
1223  * tipc_link_send_sections_fast: Entry for messages where the
1224  * destination processor is known and the header is complete,
1225  * except for total message length.
1226  * Returns user data length or errno.
1227  */
1228 int tipc_link_send_sections_fast(struct port *sender,
1229                                  struct iovec const *msg_sect,
1230                                  const u32 num_sect,
1231                                  u32 destaddr)
1232 {
1233         struct tipc_msg *hdr = &sender->publ.phdr;
1234         struct link *l_ptr;
1235         struct sk_buff *buf;
1236         struct tipc_node *node;
1237         int res;
1238         u32 selector = msg_origport(hdr) & 1;
1239
1240 again:
1241         /*
1242          * Try building message using port's max_pkt hint.
1243          * (Must not hold any locks while building message.)
1244          */
1245
1246         res = tipc_msg_build(hdr, msg_sect, num_sect, sender->publ.max_pkt,
1247                         !sender->user_port, &buf);
1248
1249         read_lock_bh(&tipc_net_lock);
1250         node = tipc_node_select(destaddr, selector);
1251         if (likely(node)) {
1252                 tipc_node_lock(node);
1253                 l_ptr = node->active_links[selector];
1254                 if (likely(l_ptr)) {
1255                         if (likely(buf)) {
1256                                 res = link_send_buf_fast(l_ptr, buf,
1257                                                          &sender->publ.max_pkt);
1258                                 if (unlikely(res < 0))
1259                                         buf_discard(buf);
1260 exit:
1261                                 tipc_node_unlock(node);
1262                                 read_unlock_bh(&tipc_net_lock);
1263                                 return res;
1264                         }
1265
1266                         /* Exit if build request was invalid */
1267
1268                         if (unlikely(res < 0))
1269                                 goto exit;
1270
1271                         /* Exit if link (or bearer) is congested */
1272
1273                         if (link_congested(l_ptr) ||
1274                             !list_empty(&l_ptr->b_ptr->cong_links)) {
1275                                 res = link_schedule_port(l_ptr,
1276                                                          sender->publ.ref, res);
1277                                 goto exit;
1278                         }
1279
1280                         /*
1281                          * Message size exceeds max_pkt hint; update hint,
1282                          * then re-try fast path or fragment the message
1283                          */
1284
1285                         sender->publ.max_pkt = l_ptr->max_pkt;
1286                         tipc_node_unlock(node);
1287                         read_unlock_bh(&tipc_net_lock);
1288
1289
1290                         if ((msg_hdr_sz(hdr) + res) <= sender->publ.max_pkt)
1291                                 goto again;
1292
1293                         return link_send_sections_long(sender, msg_sect,
1294                                                        num_sect, destaddr);
1295                 }
1296                 tipc_node_unlock(node);
1297         }
1298         read_unlock_bh(&tipc_net_lock);
1299
1300         /* Couldn't find a link to the destination node */
1301
1302         if (buf)
1303                 return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1304         if (res >= 0)
1305                 return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1306                                                  TIPC_ERR_NO_NODE);
1307         return res;
1308 }
1309
1310 /*
1311  * link_send_sections_long(): Entry for long messages where the
1312  * destination node is known and the header is complete,
1313  * inclusive total message length.
1314  * Link and bearer congestion status have been checked to be ok,
1315  * and are ignored if they change.
1316  *
1317  * Note that fragments do not use the full link MTU so that they won't have
1318  * to undergo refragmentation if link changeover causes them to be sent
1319  * over another link with an additional tunnel header added as prefix.
1320  * (Refragmentation will still occur if the other link has a smaller MTU.)
1321  *
1322  * Returns user data length or errno.
1323  */
1324 static int link_send_sections_long(struct port *sender,
1325                                    struct iovec const *msg_sect,
1326                                    u32 num_sect,
1327                                    u32 destaddr)
1328 {
1329         struct link *l_ptr;
1330         struct tipc_node *node;
1331         struct tipc_msg *hdr = &sender->publ.phdr;
1332         u32 dsz = msg_data_sz(hdr);
1333         u32 max_pkt,fragm_sz,rest;
1334         struct tipc_msg fragm_hdr;
1335         struct sk_buff *buf,*buf_chain,*prev;
1336         u32 fragm_crs,fragm_rest,hsz,sect_rest;
1337         const unchar *sect_crs;
1338         int curr_sect;
1339         u32 fragm_no;
1340
1341 again:
1342         fragm_no = 1;
1343         max_pkt = sender->publ.max_pkt - INT_H_SIZE;
1344                 /* leave room for tunnel header in case of link changeover */
1345         fragm_sz = max_pkt - INT_H_SIZE;
1346                 /* leave room for fragmentation header in each fragment */
1347         rest = dsz;
1348         fragm_crs = 0;
1349         fragm_rest = 0;
1350         sect_rest = 0;
1351         sect_crs = NULL;
1352         curr_sect = -1;
1353
1354         /* Prepare reusable fragment header: */
1355
1356         msg_dbg(hdr, ">FRAGMENTING>");
1357         tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
1358                  INT_H_SIZE, msg_destnode(hdr));
1359         msg_set_link_selector(&fragm_hdr, sender->publ.ref);
1360         msg_set_size(&fragm_hdr, max_pkt);
1361         msg_set_fragm_no(&fragm_hdr, 1);
1362
1363         /* Prepare header of first fragment: */
1364
1365         buf_chain = buf = buf_acquire(max_pkt);
1366         if (!buf)
1367                 return -ENOMEM;
1368         buf->next = NULL;
1369         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1370         hsz = msg_hdr_sz(hdr);
1371         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, hdr, hsz);
1372         msg_dbg(buf_msg(buf), ">BUILD>");
1373
1374         /* Chop up message: */
1375
1376         fragm_crs = INT_H_SIZE + hsz;
1377         fragm_rest = fragm_sz - hsz;
1378
1379         do {            /* For all sections */
1380                 u32 sz;
1381
1382                 if (!sect_rest) {
1383                         sect_rest = msg_sect[++curr_sect].iov_len;
1384                         sect_crs = (const unchar *)msg_sect[curr_sect].iov_base;
1385                 }
1386
1387                 if (sect_rest < fragm_rest)
1388                         sz = sect_rest;
1389                 else
1390                         sz = fragm_rest;
1391
1392                 if (likely(!sender->user_port)) {
1393                         if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
1394 error:
1395                                 for (; buf_chain; buf_chain = buf) {
1396                                         buf = buf_chain->next;
1397                                         buf_discard(buf_chain);
1398                                 }
1399                                 return -EFAULT;
1400                         }
1401                 } else
1402                         skb_copy_to_linear_data_offset(buf, fragm_crs,
1403                                                        sect_crs, sz);
1404                 sect_crs += sz;
1405                 sect_rest -= sz;
1406                 fragm_crs += sz;
1407                 fragm_rest -= sz;
1408                 rest -= sz;
1409
1410                 if (!fragm_rest && rest) {
1411
1412                         /* Initiate new fragment: */
1413                         if (rest <= fragm_sz) {
1414                                 fragm_sz = rest;
1415                                 msg_set_type(&fragm_hdr,LAST_FRAGMENT);
1416                         } else {
1417                                 msg_set_type(&fragm_hdr, FRAGMENT);
1418                         }
1419                         msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
1420                         msg_set_fragm_no(&fragm_hdr, ++fragm_no);
1421                         prev = buf;
1422                         buf = buf_acquire(fragm_sz + INT_H_SIZE);
1423                         if (!buf)
1424                                 goto error;
1425
1426                         buf->next = NULL;
1427                         prev->next = buf;
1428                         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1429                         fragm_crs = INT_H_SIZE;
1430                         fragm_rest = fragm_sz;
1431                         msg_dbg(buf_msg(buf),"  >BUILD>");
1432                 }
1433         }
1434         while (rest > 0);
1435
1436         /*
1437          * Now we have a buffer chain. Select a link and check
1438          * that packet size is still OK
1439          */
1440         node = tipc_node_select(destaddr, sender->publ.ref & 1);
1441         if (likely(node)) {
1442                 tipc_node_lock(node);
1443                 l_ptr = node->active_links[sender->publ.ref & 1];
1444                 if (!l_ptr) {
1445                         tipc_node_unlock(node);
1446                         goto reject;
1447                 }
1448                 if (l_ptr->max_pkt < max_pkt) {
1449                         sender->publ.max_pkt = l_ptr->max_pkt;
1450                         tipc_node_unlock(node);
1451                         for (; buf_chain; buf_chain = buf) {
1452                                 buf = buf_chain->next;
1453                                 buf_discard(buf_chain);
1454                         }
1455                         goto again;
1456                 }
1457         } else {
1458 reject:
1459                 for (; buf_chain; buf_chain = buf) {
1460                         buf = buf_chain->next;
1461                         buf_discard(buf_chain);
1462                 }
1463                 return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1464                                                  TIPC_ERR_NO_NODE);
1465         }
1466
1467         /* Append whole chain to send queue: */
1468
1469         buf = buf_chain;
1470         l_ptr->long_msg_seq_no = mod(l_ptr->long_msg_seq_no + 1);
1471         if (!l_ptr->next_out)
1472                 l_ptr->next_out = buf_chain;
1473         l_ptr->stats.sent_fragmented++;
1474         while (buf) {
1475                 struct sk_buff *next = buf->next;
1476                 struct tipc_msg *msg = buf_msg(buf);
1477
1478                 l_ptr->stats.sent_fragments++;
1479                 msg_set_long_msgno(msg, l_ptr->long_msg_seq_no);
1480                 link_add_to_outqueue(l_ptr, buf, msg);
1481                 msg_dbg(msg, ">ADD>");
1482                 buf = next;
1483         }
1484
1485         /* Send it, if possible: */
1486
1487         tipc_link_push_queue(l_ptr);
1488         tipc_node_unlock(node);
1489         return dsz;
1490 }
1491
1492 /*
1493  * tipc_link_push_packet: Push one unsent packet to the media
1494  */
1495 u32 tipc_link_push_packet(struct link *l_ptr)
1496 {
1497         struct sk_buff *buf = l_ptr->first_out;
1498         u32 r_q_size = l_ptr->retransm_queue_size;
1499         u32 r_q_head = l_ptr->retransm_queue_head;
1500
1501         /* Step to position where retransmission failed, if any,    */
1502         /* consider that buffers may have been released in meantime */
1503
1504         if (r_q_size && buf) {
1505                 u32 last = lesser(mod(r_q_head + r_q_size),
1506                                   link_last_sent(l_ptr));
1507                 u32 first = msg_seqno(buf_msg(buf));
1508
1509                 while (buf && less(first, r_q_head)) {
1510                         first = mod(first + 1);
1511                         buf = buf->next;
1512                 }
1513                 l_ptr->retransm_queue_head = r_q_head = first;
1514                 l_ptr->retransm_queue_size = r_q_size = mod(last - first);
1515         }
1516
1517         /* Continue retransmission now, if there is anything: */
1518
1519         if (r_q_size && buf) {
1520                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1521                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1522                 if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1523                         msg_dbg(buf_msg(buf), ">DEF-RETR>");
1524                         l_ptr->retransm_queue_head = mod(++r_q_head);
1525                         l_ptr->retransm_queue_size = --r_q_size;
1526                         l_ptr->stats.retransmitted++;
1527                         return 0;
1528                 } else {
1529                         l_ptr->stats.bearer_congs++;
1530                         msg_dbg(buf_msg(buf), "|>DEF-RETR>");
1531                         return PUSH_FAILED;
1532                 }
1533         }
1534
1535         /* Send deferred protocol message, if any: */
1536
1537         buf = l_ptr->proto_msg_queue;
1538         if (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-PROT>");
1543                         l_ptr->unacked_window = 0;
1544                         buf_discard(buf);
1545                         l_ptr->proto_msg_queue = NULL;
1546                         return 0;
1547                 } else {
1548                         msg_dbg(buf_msg(buf), "|>DEF-PROT>");
1549                         l_ptr->stats.bearer_congs++;
1550                         return PUSH_FAILED;
1551                 }
1552         }
1553
1554         /* Send one deferred data message, if send window not full: */
1555
1556         buf = l_ptr->next_out;
1557         if (buf) {
1558                 struct tipc_msg *msg = buf_msg(buf);
1559                 u32 next = msg_seqno(msg);
1560                 u32 first = msg_seqno(buf_msg(l_ptr->first_out));
1561
1562                 if (mod(next - first) < l_ptr->queue_limit[0]) {
1563                         msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1564                         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1565                         if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1566                                 if (msg_user(msg) == MSG_BUNDLER)
1567                                         msg_set_type(msg, CLOSED_MSG);
1568                                 msg_dbg(msg, ">PUSH-DATA>");
1569                                 l_ptr->next_out = buf->next;
1570                                 return 0;
1571                         } else {
1572                                 msg_dbg(msg, "|PUSH-DATA|");
1573                                 l_ptr->stats.bearer_congs++;
1574                                 return PUSH_FAILED;
1575                         }
1576                 }
1577         }
1578         return PUSH_FINISHED;
1579 }
1580
1581 /*
1582  * push_queue(): push out the unsent messages of a link where
1583  *               congestion has abated. Node is locked
1584  */
1585 void tipc_link_push_queue(struct link *l_ptr)
1586 {
1587         u32 res;
1588
1589         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr))
1590                 return;
1591
1592         do {
1593                 res = tipc_link_push_packet(l_ptr);
1594         } while (!res);
1595
1596         if (res == PUSH_FAILED)
1597                 tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1598 }
1599
1600 static void link_reset_all(unsigned long addr)
1601 {
1602         struct tipc_node *n_ptr;
1603         char addr_string[16];
1604         u32 i;
1605
1606         read_lock_bh(&tipc_net_lock);
1607         n_ptr = tipc_node_find((u32)addr);
1608         if (!n_ptr) {
1609                 read_unlock_bh(&tipc_net_lock);
1610                 return; /* node no longer exists */
1611         }
1612
1613         tipc_node_lock(n_ptr);
1614
1615         warn("Resetting all links to %s\n",
1616              tipc_addr_string_fill(addr_string, n_ptr->addr));
1617
1618         for (i = 0; i < MAX_BEARERS; i++) {
1619                 if (n_ptr->links[i]) {
1620                         link_print(n_ptr->links[i], TIPC_OUTPUT,
1621                                    "Resetting link\n");
1622                         tipc_link_reset(n_ptr->links[i]);
1623                 }
1624         }
1625
1626         tipc_node_unlock(n_ptr);
1627         read_unlock_bh(&tipc_net_lock);
1628 }
1629
1630 static void link_retransmit_failure(struct link *l_ptr, struct sk_buff *buf)
1631 {
1632         struct tipc_msg *msg = buf_msg(buf);
1633
1634         warn("Retransmission failure on link <%s>\n", l_ptr->name);
1635         tipc_msg_dbg(TIPC_OUTPUT, msg, ">RETR-FAIL>");
1636
1637         if (l_ptr->addr) {
1638
1639                 /* Handle failure on standard link */
1640
1641                 link_print(l_ptr, TIPC_OUTPUT, "Resetting link\n");
1642                 tipc_link_reset(l_ptr);
1643
1644         } else {
1645
1646                 /* Handle failure on broadcast link */
1647
1648                 struct tipc_node *n_ptr;
1649                 char addr_string[16];
1650
1651                 tipc_printf(TIPC_OUTPUT, "Msg seq number: %u,  ", msg_seqno(msg));
1652                 tipc_printf(TIPC_OUTPUT, "Outstanding acks: %lu\n",
1653                                      (unsigned long) TIPC_SKB_CB(buf)->handle);
1654
1655                 n_ptr = l_ptr->owner->next;
1656                 tipc_node_lock(n_ptr);
1657
1658                 tipc_addr_string_fill(addr_string, n_ptr->addr);
1659                 tipc_printf(TIPC_OUTPUT, "Multicast link info for %s\n", addr_string);
1660                 tipc_printf(TIPC_OUTPUT, "Supported: %d,  ", n_ptr->bclink.supported);
1661                 tipc_printf(TIPC_OUTPUT, "Acked: %u\n", n_ptr->bclink.acked);
1662                 tipc_printf(TIPC_OUTPUT, "Last in: %u,  ", n_ptr->bclink.last_in);
1663                 tipc_printf(TIPC_OUTPUT, "Gap after: %u,  ", n_ptr->bclink.gap_after);
1664                 tipc_printf(TIPC_OUTPUT, "Gap to: %u\n", n_ptr->bclink.gap_to);
1665                 tipc_printf(TIPC_OUTPUT, "Nack sync: %u\n\n", n_ptr->bclink.nack_sync);
1666
1667                 tipc_k_signal((Handler)link_reset_all, (unsigned long)n_ptr->addr);
1668
1669                 tipc_node_unlock(n_ptr);
1670
1671                 l_ptr->stale_count = 0;
1672         }
1673 }
1674
1675 void tipc_link_retransmit(struct link *l_ptr, struct sk_buff *buf,
1676                           u32 retransmits)
1677 {
1678         struct tipc_msg *msg;
1679
1680         if (!buf)
1681                 return;
1682
1683         msg = buf_msg(buf);
1684
1685         dbg("Retransmitting %u in link %x\n", retransmits, l_ptr);
1686
1687         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
1688                 if (l_ptr->retransm_queue_size == 0) {
1689                         msg_dbg(msg, ">NO_RETR->BCONG>");
1690                         dbg_print_link(l_ptr, "   ");
1691                         l_ptr->retransm_queue_head = msg_seqno(msg);
1692                         l_ptr->retransm_queue_size = retransmits;
1693                 } else {
1694                         err("Unexpected retransmit on link %s (qsize=%d)\n",
1695                             l_ptr->name, l_ptr->retransm_queue_size);
1696                 }
1697                 return;
1698         } else {
1699                 /* Detect repeated retransmit failures on uncongested bearer */
1700
1701                 if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1702                         if (++l_ptr->stale_count > 100) {
1703                                 link_retransmit_failure(l_ptr, buf);
1704                                 return;
1705                         }
1706                 } else {
1707                         l_ptr->last_retransmitted = msg_seqno(msg);
1708                         l_ptr->stale_count = 1;
1709                 }
1710         }
1711
1712         while (retransmits && (buf != l_ptr->next_out) && buf) {
1713                 msg = buf_msg(buf);
1714                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1715                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1716                 if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1717                         msg_dbg(buf_msg(buf), ">RETR>");
1718                         buf = buf->next;
1719                         retransmits--;
1720                         l_ptr->stats.retransmitted++;
1721                 } else {
1722                         tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1723                         l_ptr->stats.bearer_congs++;
1724                         l_ptr->retransm_queue_head = msg_seqno(buf_msg(buf));
1725                         l_ptr->retransm_queue_size = retransmits;
1726                         return;
1727                 }
1728         }
1729
1730         l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
1731 }
1732
1733 /**
1734  * link_insert_deferred_queue - insert deferred messages back into receive chain
1735  */
1736
1737 static struct sk_buff *link_insert_deferred_queue(struct link *l_ptr,
1738                                                   struct sk_buff *buf)
1739 {
1740         u32 seq_no;
1741
1742         if (l_ptr->oldest_deferred_in == NULL)
1743                 return buf;
1744
1745         seq_no = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
1746         if (seq_no == mod(l_ptr->next_in_no)) {
1747                 l_ptr->newest_deferred_in->next = buf;
1748                 buf = l_ptr->oldest_deferred_in;
1749                 l_ptr->oldest_deferred_in = NULL;
1750                 l_ptr->deferred_inqueue_sz = 0;
1751         }
1752         return buf;
1753 }
1754
1755 /**
1756  * link_recv_buf_validate - validate basic format of received message
1757  *
1758  * This routine ensures a TIPC message has an acceptable header, and at least
1759  * as much data as the header indicates it should.  The routine also ensures
1760  * that the entire message header is stored in the main fragment of the message
1761  * buffer, to simplify future access to message header fields.
1762  *
1763  * Note: Having extra info present in the message header or data areas is OK.
1764  * TIPC will ignore the excess, under the assumption that it is optional info
1765  * introduced by a later release of the protocol.
1766  */
1767
1768 static int link_recv_buf_validate(struct sk_buff *buf)
1769 {
1770         static u32 min_data_hdr_size[8] = {
1771                 SHORT_H_SIZE, MCAST_H_SIZE, LONG_H_SIZE, DIR_MSG_H_SIZE,
1772                 MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE
1773                 };
1774
1775         struct tipc_msg *msg;
1776         u32 tipc_hdr[2];
1777         u32 size;
1778         u32 hdr_size;
1779         u32 min_hdr_size;
1780
1781         if (unlikely(buf->len < MIN_H_SIZE))
1782                 return 0;
1783
1784         msg = skb_header_pointer(buf, 0, sizeof(tipc_hdr), tipc_hdr);
1785         if (msg == NULL)
1786                 return 0;
1787
1788         if (unlikely(msg_version(msg) != TIPC_VERSION))
1789                 return 0;
1790
1791         size = msg_size(msg);
1792         hdr_size = msg_hdr_sz(msg);
1793         min_hdr_size = msg_isdata(msg) ?
1794                 min_data_hdr_size[msg_type(msg)] : INT_H_SIZE;
1795
1796         if (unlikely((hdr_size < min_hdr_size) ||
1797                      (size < hdr_size) ||
1798                      (buf->len < size) ||
1799                      (size - hdr_size > TIPC_MAX_USER_MSG_SIZE)))
1800                 return 0;
1801
1802         return pskb_may_pull(buf, hdr_size);
1803 }
1804
1805 void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *tb_ptr)
1806 {
1807         read_lock_bh(&tipc_net_lock);
1808         while (head) {
1809                 struct bearer *b_ptr = (struct bearer *)tb_ptr;
1810                 struct tipc_node *n_ptr;
1811                 struct link *l_ptr;
1812                 struct sk_buff *crs;
1813                 struct sk_buff *buf = head;
1814                 struct tipc_msg *msg;
1815                 u32 seq_no;
1816                 u32 ackd;
1817                 u32 released = 0;
1818                 int type;
1819
1820                 head = head->next;
1821
1822                 /* Ensure message is well-formed */
1823
1824                 if (unlikely(!link_recv_buf_validate(buf)))
1825                         goto cont;
1826
1827                 /* Ensure message data is a single contiguous unit */
1828
1829                 if (unlikely(buf_linearize(buf))) {
1830                         goto cont;
1831                 }
1832
1833                 /* Handle arrival of a non-unicast link message */
1834
1835                 msg = buf_msg(buf);
1836
1837                 if (unlikely(msg_non_seq(msg))) {
1838                         if (msg_user(msg) ==  LINK_CONFIG)
1839                                 tipc_disc_recv_msg(buf, b_ptr);
1840                         else
1841                                 tipc_bclink_recv_pkt(buf);
1842                         continue;
1843                 }
1844
1845                 if (unlikely(!msg_short(msg) &&
1846                              (msg_destnode(msg) != tipc_own_addr)))
1847                         goto cont;
1848
1849                 /* Discard non-routeable messages destined for another node */
1850
1851                 if (unlikely(!msg_isdata(msg) &&
1852                              (msg_destnode(msg) != tipc_own_addr))) {
1853                         if ((msg_user(msg) != CONN_MANAGER) &&
1854                             (msg_user(msg) != MSG_FRAGMENTER))
1855                                 goto cont;
1856                 }
1857
1858                 /* Locate unicast link endpoint that should handle message */
1859
1860                 n_ptr = tipc_node_find(msg_prevnode(msg));
1861                 if (unlikely(!n_ptr))
1862                         goto cont;
1863                 tipc_node_lock(n_ptr);
1864
1865                 l_ptr = n_ptr->links[b_ptr->identity];
1866                 if (unlikely(!l_ptr)) {
1867                         tipc_node_unlock(n_ptr);
1868                         goto cont;
1869                 }
1870
1871                 /* Validate message sequence number info */
1872
1873                 seq_no = msg_seqno(msg);
1874                 ackd = msg_ack(msg);
1875
1876                 /* Release acked messages */
1877
1878                 if (less(n_ptr->bclink.acked, msg_bcast_ack(msg))) {
1879                         if (tipc_node_is_up(n_ptr) && n_ptr->bclink.supported)
1880                                 tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1881                 }
1882
1883                 crs = l_ptr->first_out;
1884                 while ((crs != l_ptr->next_out) &&
1885                        less_eq(msg_seqno(buf_msg(crs)), ackd)) {
1886                         struct sk_buff *next = crs->next;
1887
1888                         buf_discard(crs);
1889                         crs = next;
1890                         released++;
1891                 }
1892                 if (released) {
1893                         l_ptr->first_out = crs;
1894                         l_ptr->out_queue_size -= released;
1895                 }
1896
1897                 /* Try sending any messages link endpoint has pending */
1898
1899                 if (unlikely(l_ptr->next_out))
1900                         tipc_link_push_queue(l_ptr);
1901                 if (unlikely(!list_empty(&l_ptr->waiting_ports)))
1902                         tipc_link_wakeup_ports(l_ptr, 0);
1903                 if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1904                         l_ptr->stats.sent_acks++;
1905                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1906                 }
1907
1908                 /* Now (finally!) process the incoming message */
1909
1910 protocol_check:
1911                 if (likely(link_working_working(l_ptr))) {
1912                         if (likely(seq_no == mod(l_ptr->next_in_no))) {
1913                                 l_ptr->next_in_no++;
1914                                 if (unlikely(l_ptr->oldest_deferred_in))
1915                                         head = link_insert_deferred_queue(l_ptr,
1916                                                                           head);
1917                                 if (likely(msg_is_dest(msg, tipc_own_addr))) {
1918 deliver:
1919                                         if (likely(msg_isdata(msg))) {
1920                                                 tipc_node_unlock(n_ptr);
1921                                                 tipc_port_recv_msg(buf);
1922                                                 continue;
1923                                         }
1924                                         switch (msg_user(msg)) {
1925                                         case MSG_BUNDLER:
1926                                                 l_ptr->stats.recv_bundles++;
1927                                                 l_ptr->stats.recv_bundled +=
1928                                                         msg_msgcnt(msg);
1929                                                 tipc_node_unlock(n_ptr);
1930                                                 tipc_link_recv_bundle(buf);
1931                                                 continue;
1932                                         case ROUTE_DISTRIBUTOR:
1933                                                 tipc_node_unlock(n_ptr);
1934                                                 tipc_cltr_recv_routing_table(buf);
1935                                                 continue;
1936                                         case NAME_DISTRIBUTOR:
1937                                                 tipc_node_unlock(n_ptr);
1938                                                 tipc_named_recv(buf);
1939                                                 continue;
1940                                         case CONN_MANAGER:
1941                                                 tipc_node_unlock(n_ptr);
1942                                                 tipc_port_recv_proto_msg(buf);
1943                                                 continue;
1944                                         case MSG_FRAGMENTER:
1945                                                 l_ptr->stats.recv_fragments++;
1946                                                 if (tipc_link_recv_fragment(&l_ptr->defragm_buf,
1947                                                                             &buf, &msg)) {
1948                                                         l_ptr->stats.recv_fragmented++;
1949                                                         goto deliver;
1950                                                 }
1951                                                 break;
1952                                         case CHANGEOVER_PROTOCOL:
1953                                                 type = msg_type(msg);
1954                                                 if (link_recv_changeover_msg(&l_ptr, &buf)) {
1955                                                         msg = buf_msg(buf);
1956                                                         seq_no = msg_seqno(msg);
1957                                                         if (type == ORIGINAL_MSG)
1958                                                                 goto deliver;
1959                                                         goto protocol_check;
1960                                                 }
1961                                                 break;
1962                                         }
1963                                 }
1964                                 tipc_node_unlock(n_ptr);
1965                                 tipc_net_route_msg(buf);
1966                                 continue;
1967                         }
1968                         link_handle_out_of_seq_msg(l_ptr, buf);
1969                         head = link_insert_deferred_queue(l_ptr, head);
1970                         tipc_node_unlock(n_ptr);
1971                         continue;
1972                 }
1973
1974                 if (msg_user(msg) == LINK_PROTOCOL) {
1975                         link_recv_proto_msg(l_ptr, buf);
1976                         head = link_insert_deferred_queue(l_ptr, head);
1977                         tipc_node_unlock(n_ptr);
1978                         continue;
1979                 }
1980                 msg_dbg(msg,"NSEQ<REC<");
1981                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1982
1983                 if (link_working_working(l_ptr)) {
1984                         /* Re-insert in front of queue */
1985                         msg_dbg(msg,"RECV-REINS:");
1986                         buf->next = head;
1987                         head = buf;
1988                         tipc_node_unlock(n_ptr);
1989                         continue;
1990                 }
1991                 tipc_node_unlock(n_ptr);
1992 cont:
1993                 buf_discard(buf);
1994         }
1995         read_unlock_bh(&tipc_net_lock);
1996 }
1997
1998 /*
1999  * link_defer_buf(): Sort a received out-of-sequence packet
2000  *                   into the deferred reception queue.
2001  * Returns the increase of the queue length,i.e. 0 or 1
2002  */
2003
2004 u32 tipc_link_defer_pkt(struct sk_buff **head,
2005                         struct sk_buff **tail,
2006                         struct sk_buff *buf)
2007 {
2008         struct sk_buff *prev = NULL;
2009         struct sk_buff *crs = *head;
2010         u32 seq_no = msg_seqno(buf_msg(buf));
2011
2012         buf->next = NULL;
2013
2014         /* Empty queue ? */
2015         if (*head == NULL) {
2016                 *head = *tail = buf;
2017                 return 1;
2018         }
2019
2020         /* Last ? */
2021         if (less(msg_seqno(buf_msg(*tail)), seq_no)) {
2022                 (*tail)->next = buf;
2023                 *tail = buf;
2024                 return 1;
2025         }
2026
2027         /* Scan through queue and sort it in */
2028         do {
2029                 struct tipc_msg *msg = buf_msg(crs);
2030
2031                 if (less(seq_no, msg_seqno(msg))) {
2032                         buf->next = crs;
2033                         if (prev)
2034                                 prev->next = buf;
2035                         else
2036                                 *head = buf;
2037                         return 1;
2038                 }
2039                 if (seq_no == msg_seqno(msg)) {
2040                         break;
2041                 }
2042                 prev = crs;
2043                 crs = crs->next;
2044         }
2045         while (crs);
2046
2047         /* Message is a duplicate of an existing message */
2048
2049         buf_discard(buf);
2050         return 0;
2051 }
2052
2053 /**
2054  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
2055  */
2056
2057 static void link_handle_out_of_seq_msg(struct link *l_ptr,
2058                                        struct sk_buff *buf)
2059 {
2060         u32 seq_no = msg_seqno(buf_msg(buf));
2061
2062         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
2063                 link_recv_proto_msg(l_ptr, buf);
2064                 return;
2065         }
2066
2067         dbg("rx OOS msg: seq_no %u, expecting %u (%u)\n",
2068             seq_no, mod(l_ptr->next_in_no), l_ptr->next_in_no);
2069
2070         /* Record OOS packet arrival (force mismatch on next timeout) */
2071
2072         l_ptr->checkpoint--;
2073
2074         /*
2075          * Discard packet if a duplicate; otherwise add it to deferred queue
2076          * and notify peer of gap as per protocol specification
2077          */
2078
2079         if (less(seq_no, mod(l_ptr->next_in_no))) {
2080                 l_ptr->stats.duplicates++;
2081                 buf_discard(buf);
2082                 return;
2083         }
2084
2085         if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
2086                                 &l_ptr->newest_deferred_in, buf)) {
2087                 l_ptr->deferred_inqueue_sz++;
2088                 l_ptr->stats.deferred_recv++;
2089                 if ((l_ptr->deferred_inqueue_sz % 16) == 1)
2090                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
2091         } else
2092                 l_ptr->stats.duplicates++;
2093 }
2094
2095 /*
2096  * Send protocol message to the other endpoint.
2097  */
2098 void tipc_link_send_proto_msg(struct link *l_ptr, u32 msg_typ, int probe_msg,
2099                               u32 gap, u32 tolerance, u32 priority, u32 ack_mtu)
2100 {
2101         struct sk_buff *buf = NULL;
2102         struct tipc_msg *msg = l_ptr->pmsg;
2103         u32 msg_size = sizeof(l_ptr->proto_msg);
2104
2105         if (link_blocked(l_ptr))
2106                 return;
2107         msg_set_type(msg, msg_typ);
2108         msg_set_net_plane(msg, l_ptr->b_ptr->net_plane);
2109         msg_set_bcast_ack(msg, mod(l_ptr->owner->bclink.last_in));
2110         msg_set_last_bcast(msg, tipc_bclink_get_last_sent());
2111
2112         if (msg_typ == STATE_MSG) {
2113                 u32 next_sent = mod(l_ptr->next_out_no);
2114
2115                 if (!tipc_link_is_up(l_ptr))
2116                         return;
2117                 if (l_ptr->next_out)
2118                         next_sent = msg_seqno(buf_msg(l_ptr->next_out));
2119                 msg_set_next_sent(msg, next_sent);
2120                 if (l_ptr->oldest_deferred_in) {
2121                         u32 rec = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
2122                         gap = mod(rec - mod(l_ptr->next_in_no));
2123                 }
2124                 msg_set_seq_gap(msg, gap);
2125                 if (gap)
2126                         l_ptr->stats.sent_nacks++;
2127                 msg_set_link_tolerance(msg, tolerance);
2128                 msg_set_linkprio(msg, priority);
2129                 msg_set_max_pkt(msg, ack_mtu);
2130                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
2131                 msg_set_probe(msg, probe_msg != 0);
2132                 if (probe_msg) {
2133                         u32 mtu = l_ptr->max_pkt;
2134
2135                         if ((mtu < l_ptr->max_pkt_target) &&
2136                             link_working_working(l_ptr) &&
2137                             l_ptr->fsm_msg_cnt) {
2138                                 msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
2139                                 if (l_ptr->max_pkt_probes == 10) {
2140                                         l_ptr->max_pkt_target = (msg_size - 4);
2141                                         l_ptr->max_pkt_probes = 0;
2142                                         msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
2143                                 }
2144                                 l_ptr->max_pkt_probes++;
2145                         }
2146
2147                         l_ptr->stats.sent_probes++;
2148                 }
2149                 l_ptr->stats.sent_states++;
2150         } else {                /* RESET_MSG or ACTIVATE_MSG */
2151                 msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
2152                 msg_set_seq_gap(msg, 0);
2153                 msg_set_next_sent(msg, 1);
2154                 msg_set_link_tolerance(msg, l_ptr->tolerance);
2155                 msg_set_linkprio(msg, l_ptr->priority);
2156                 msg_set_max_pkt(msg, l_ptr->max_pkt_target);
2157         }
2158
2159         if (tipc_node_has_redundant_links(l_ptr->owner)) {
2160                 msg_set_redundant_link(msg);
2161         } else {
2162                 msg_clear_redundant_link(msg);
2163         }
2164         msg_set_linkprio(msg, l_ptr->priority);
2165
2166         /* Ensure sequence number will not fit : */
2167
2168         msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
2169
2170         /* Congestion? */
2171
2172         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
2173                 if (!l_ptr->proto_msg_queue) {
2174                         l_ptr->proto_msg_queue =
2175                                 buf_acquire(sizeof(l_ptr->proto_msg));
2176                 }
2177                 buf = l_ptr->proto_msg_queue;
2178                 if (!buf)
2179                         return;
2180                 skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
2181                 return;
2182         }
2183         msg_set_timestamp(msg, jiffies_to_msecs(jiffies));
2184
2185         /* Message can be sent */
2186
2187         msg_dbg(msg, ">>");
2188
2189         buf = buf_acquire(msg_size);
2190         if (!buf)
2191                 return;
2192
2193         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
2194         msg_set_size(buf_msg(buf), msg_size);
2195
2196         if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
2197                 l_ptr->unacked_window = 0;
2198                 buf_discard(buf);
2199                 return;
2200         }
2201
2202         /* New congestion */
2203         tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
2204         l_ptr->proto_msg_queue = buf;
2205         l_ptr->stats.bearer_congs++;
2206 }
2207
2208 /*
2209  * Receive protocol message :
2210  * Note that network plane id propagates through the network, and may
2211  * change at any time. The node with lowest address rules
2212  */
2213
2214 static void link_recv_proto_msg(struct link *l_ptr, struct sk_buff *buf)
2215 {
2216         u32 rec_gap = 0;
2217         u32 max_pkt_info;
2218         u32 max_pkt_ack;
2219         u32 msg_tol;
2220         struct tipc_msg *msg = buf_msg(buf);
2221
2222         dbg("AT(%u):", jiffies_to_msecs(jiffies));
2223         msg_dbg(msg, "<<");
2224         if (link_blocked(l_ptr))
2225                 goto exit;
2226
2227         /* record unnumbered packet arrival (force mismatch on next timeout) */
2228
2229         l_ptr->checkpoint--;
2230
2231         if (l_ptr->b_ptr->net_plane != msg_net_plane(msg))
2232                 if (tipc_own_addr > msg_prevnode(msg))
2233                         l_ptr->b_ptr->net_plane = msg_net_plane(msg);
2234
2235         l_ptr->owner->permit_changeover = msg_redundant_link(msg);
2236
2237         switch (msg_type(msg)) {
2238
2239         case RESET_MSG:
2240                 if (!link_working_unknown(l_ptr) &&
2241                     (l_ptr->peer_session != INVALID_SESSION)) {
2242                         if (msg_session(msg) == l_ptr->peer_session) {
2243                                 dbg("Duplicate RESET: %u<->%u\n",
2244                                     msg_session(msg), l_ptr->peer_session);
2245                                 break; /* duplicate: ignore */
2246                         }
2247                 }
2248                 /* fall thru' */
2249         case ACTIVATE_MSG:
2250                 /* Update link settings according other endpoint's values */
2251
2252                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
2253
2254                 if ((msg_tol = msg_link_tolerance(msg)) &&
2255                     (msg_tol > l_ptr->tolerance))
2256                         link_set_supervision_props(l_ptr, msg_tol);
2257
2258                 if (msg_linkprio(msg) > l_ptr->priority)
2259                         l_ptr->priority = msg_linkprio(msg);
2260
2261                 max_pkt_info = msg_max_pkt(msg);
2262                 if (max_pkt_info) {
2263                         if (max_pkt_info < l_ptr->max_pkt_target)
2264                                 l_ptr->max_pkt_target = max_pkt_info;
2265                         if (l_ptr->max_pkt > l_ptr->max_pkt_target)
2266                                 l_ptr->max_pkt = l_ptr->max_pkt_target;
2267                 } else {
2268                         l_ptr->max_pkt = l_ptr->max_pkt_target;
2269                 }
2270                 l_ptr->owner->bclink.supported = (max_pkt_info != 0);
2271
2272                 link_state_event(l_ptr, msg_type(msg));
2273
2274                 l_ptr->peer_session = msg_session(msg);
2275                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
2276
2277                 /* Synchronize broadcast sequence numbers */
2278                 if (!tipc_node_has_redundant_links(l_ptr->owner)) {
2279                         l_ptr->owner->bclink.last_in = mod(msg_last_bcast(msg));
2280                 }
2281                 break;
2282         case STATE_MSG:
2283
2284                 if ((msg_tol = msg_link_tolerance(msg)))
2285                         link_set_supervision_props(l_ptr, msg_tol);
2286
2287                 if (msg_linkprio(msg) &&
2288                     (msg_linkprio(msg) != l_ptr->priority)) {
2289                         warn("Resetting link <%s>, priority change %u->%u\n",
2290                              l_ptr->name, l_ptr->priority, msg_linkprio(msg));
2291                         l_ptr->priority = msg_linkprio(msg);
2292                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
2293                         break;
2294                 }
2295                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
2296                 l_ptr->stats.recv_states++;
2297                 if (link_reset_unknown(l_ptr))
2298                         break;
2299
2300                 if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
2301                         rec_gap = mod(msg_next_sent(msg) -
2302                                       mod(l_ptr->next_in_no));
2303                 }
2304
2305                 max_pkt_ack = msg_max_pkt(msg);
2306                 if (max_pkt_ack > l_ptr->max_pkt) {
2307                         dbg("Link <%s> updated MTU %u -> %u\n",
2308                             l_ptr->name, l_ptr->max_pkt, max_pkt_ack);
2309                         l_ptr->max_pkt = max_pkt_ack;
2310                         l_ptr->max_pkt_probes = 0;
2311                 }
2312
2313                 max_pkt_ack = 0;
2314                 if (msg_probe(msg)) {
2315                         l_ptr->stats.recv_probes++;
2316                         if (msg_size(msg) > sizeof(l_ptr->proto_msg)) {
2317                                 max_pkt_ack = msg_size(msg);
2318                         }
2319                 }
2320
2321                 /* Protocol message before retransmits, reduce loss risk */
2322
2323                 tipc_bclink_check_gap(l_ptr->owner, msg_last_bcast(msg));
2324
2325                 if (rec_gap || (msg_probe(msg))) {
2326                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2327                                                  0, rec_gap, 0, 0, max_pkt_ack);
2328                 }
2329                 if (msg_seq_gap(msg)) {
2330                         msg_dbg(msg, "With Gap:");
2331                         l_ptr->stats.recv_nacks++;
2332                         tipc_link_retransmit(l_ptr, l_ptr->first_out,
2333                                              msg_seq_gap(msg));
2334                 }
2335                 break;
2336         default:
2337                 msg_dbg(buf_msg(buf), "<DISCARDING UNKNOWN<");
2338         }
2339 exit:
2340         buf_discard(buf);
2341 }
2342
2343
2344 /*
2345  * tipc_link_tunnel(): Send one message via a link belonging to
2346  * another bearer. Owner node is locked.
2347  */
2348 void tipc_link_tunnel(struct link *l_ptr,
2349                       struct tipc_msg *tunnel_hdr,
2350                       struct tipc_msg  *msg,
2351                       u32 selector)
2352 {
2353         struct link *tunnel;
2354         struct sk_buff *buf;
2355         u32 length = msg_size(msg);
2356
2357         tunnel = l_ptr->owner->active_links[selector & 1];
2358         if (!tipc_link_is_up(tunnel)) {
2359                 warn("Link changeover error, "
2360                      "tunnel link no longer available\n");
2361                 return;
2362         }
2363         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
2364         buf = buf_acquire(length + INT_H_SIZE);
2365         if (!buf) {
2366                 warn("Link changeover error, "
2367                      "unable to send tunnel msg\n");
2368                 return;
2369         }
2370         skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
2371         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, msg, length);
2372         dbg("%c->%c:", l_ptr->b_ptr->net_plane, tunnel->b_ptr->net_plane);
2373         msg_dbg(buf_msg(buf), ">SEND>");
2374         tipc_link_send_buf(tunnel, buf);
2375 }
2376
2377
2378
2379 /*
2380  * changeover(): Send whole message queue via the remaining link
2381  *               Owner node is locked.
2382  */
2383
2384 void tipc_link_changeover(struct link *l_ptr)
2385 {
2386         u32 msgcount = l_ptr->out_queue_size;
2387         struct sk_buff *crs = l_ptr->first_out;
2388         struct link *tunnel = l_ptr->owner->active_links[0];
2389         struct tipc_msg tunnel_hdr;
2390         int split_bundles;
2391
2392         if (!tunnel)
2393                 return;
2394
2395         if (!l_ptr->owner->permit_changeover) {
2396                 warn("Link changeover error, "
2397                      "peer did not permit changeover\n");
2398                 return;
2399         }
2400
2401         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2402                  ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
2403         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2404         msg_set_msgcnt(&tunnel_hdr, msgcount);
2405         dbg("Link changeover requires %u tunnel messages\n", msgcount);
2406
2407         if (!l_ptr->first_out) {
2408                 struct sk_buff *buf;
2409
2410                 buf = buf_acquire(INT_H_SIZE);
2411                 if (buf) {
2412                         skb_copy_to_linear_data(buf, &tunnel_hdr, INT_H_SIZE);
2413                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
2414                         dbg("%c->%c:", l_ptr->b_ptr->net_plane,
2415                             tunnel->b_ptr->net_plane);
2416                         msg_dbg(&tunnel_hdr, "EMPTY>SEND>");
2417                         tipc_link_send_buf(tunnel, buf);
2418                 } else {
2419                         warn("Link changeover error, "
2420                              "unable to send changeover msg\n");
2421                 }
2422                 return;
2423         }
2424
2425         split_bundles = (l_ptr->owner->active_links[0] !=
2426                          l_ptr->owner->active_links[1]);
2427
2428         while (crs) {
2429                 struct tipc_msg *msg = buf_msg(crs);
2430
2431                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
2432                         struct tipc_msg *m = msg_get_wrapped(msg);
2433                         unchar* pos = (unchar*)m;
2434
2435                         msgcount = msg_msgcnt(msg);
2436                         while (msgcount--) {
2437                                 msg_set_seqno(m,msg_seqno(msg));
2438                                 tipc_link_tunnel(l_ptr, &tunnel_hdr, m,
2439                                                  msg_link_selector(m));
2440                                 pos += align(msg_size(m));
2441                                 m = (struct tipc_msg *)pos;
2442                         }
2443                 } else {
2444                         tipc_link_tunnel(l_ptr, &tunnel_hdr, msg,
2445                                          msg_link_selector(msg));
2446                 }
2447                 crs = crs->next;
2448         }
2449 }
2450
2451 void tipc_link_send_duplicate(struct link *l_ptr, struct link *tunnel)
2452 {
2453         struct sk_buff *iter;
2454         struct tipc_msg tunnel_hdr;
2455
2456         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2457                  DUPLICATE_MSG, INT_H_SIZE, l_ptr->addr);
2458         msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
2459         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2460         iter = l_ptr->first_out;
2461         while (iter) {
2462                 struct sk_buff *outbuf;
2463                 struct tipc_msg *msg = buf_msg(iter);
2464                 u32 length = msg_size(msg);
2465
2466                 if (msg_user(msg) == MSG_BUNDLER)
2467                         msg_set_type(msg, CLOSED_MSG);
2468                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));   /* Update */
2469                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
2470                 msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
2471                 outbuf = buf_acquire(length + INT_H_SIZE);
2472                 if (outbuf == NULL) {
2473                         warn("Link changeover error, "
2474                              "unable to send duplicate msg\n");
2475                         return;
2476                 }
2477                 skb_copy_to_linear_data(outbuf, &tunnel_hdr, INT_H_SIZE);
2478                 skb_copy_to_linear_data_offset(outbuf, INT_H_SIZE, iter->data,
2479                                                length);
2480                 dbg("%c->%c:", l_ptr->b_ptr->net_plane,
2481                     tunnel->b_ptr->net_plane);
2482                 msg_dbg(buf_msg(outbuf), ">SEND>");
2483                 tipc_link_send_buf(tunnel, outbuf);
2484                 if (!tipc_link_is_up(l_ptr))
2485                         return;
2486                 iter = iter->next;
2487         }
2488 }
2489
2490
2491
2492 /**
2493  * buf_extract - extracts embedded TIPC message from another message
2494  * @skb: encapsulating message buffer
2495  * @from_pos: offset to extract from
2496  *
2497  * Returns a new message buffer containing an embedded message.  The
2498  * encapsulating message itself is left unchanged.
2499  */
2500
2501 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
2502 {
2503         struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
2504         u32 size = msg_size(msg);
2505         struct sk_buff *eb;
2506
2507         eb = buf_acquire(size);
2508         if (eb)
2509                 skb_copy_to_linear_data(eb, msg, size);
2510         return eb;
2511 }
2512
2513 /*
2514  *  link_recv_changeover_msg(): Receive tunneled packet sent
2515  *  via other link. Node is locked. Return extracted buffer.
2516  */
2517
2518 static int link_recv_changeover_msg(struct link **l_ptr,
2519                                     struct sk_buff **buf)
2520 {
2521         struct sk_buff *tunnel_buf = *buf;
2522         struct link *dest_link;
2523         struct tipc_msg *msg;
2524         struct tipc_msg *tunnel_msg = buf_msg(tunnel_buf);
2525         u32 msg_typ = msg_type(tunnel_msg);
2526         u32 msg_count = msg_msgcnt(tunnel_msg);
2527
2528         dest_link = (*l_ptr)->owner->links[msg_bearer_id(tunnel_msg)];
2529         if (!dest_link) {
2530                 msg_dbg(tunnel_msg, "NOLINK/<REC<");
2531                 goto exit;
2532         }
2533         if (dest_link == *l_ptr) {
2534                 err("Unexpected changeover message on link <%s>\n",
2535                     (*l_ptr)->name);
2536                 goto exit;
2537         }
2538         dbg("%c<-%c:", dest_link->b_ptr->net_plane,
2539             (*l_ptr)->b_ptr->net_plane);
2540         *l_ptr = dest_link;
2541         msg = msg_get_wrapped(tunnel_msg);
2542
2543         if (msg_typ == DUPLICATE_MSG) {
2544                 if (less(msg_seqno(msg), mod(dest_link->next_in_no))) {
2545                         msg_dbg(tunnel_msg, "DROP/<REC<");
2546                         goto exit;
2547                 }
2548                 *buf = buf_extract(tunnel_buf,INT_H_SIZE);
2549                 if (*buf == NULL) {
2550                         warn("Link changeover error, duplicate msg dropped\n");
2551                         goto exit;
2552                 }
2553                 msg_dbg(tunnel_msg, "TNL<REC<");
2554                 buf_discard(tunnel_buf);
2555                 return 1;
2556         }
2557
2558         /* First original message ?: */
2559
2560         if (tipc_link_is_up(dest_link)) {
2561                 msg_dbg(tunnel_msg, "UP/FIRST/<REC<");
2562                 info("Resetting link <%s>, changeover initiated by peer\n",
2563                      dest_link->name);
2564                 tipc_link_reset(dest_link);
2565                 dest_link->exp_msg_count = msg_count;
2566                 dbg("Expecting %u tunnelled messages\n", msg_count);
2567                 if (!msg_count)
2568                         goto exit;
2569         } else if (dest_link->exp_msg_count == START_CHANGEOVER) {
2570                 msg_dbg(tunnel_msg, "BLK/FIRST/<REC<");
2571                 dest_link->exp_msg_count = msg_count;
2572                 dbg("Expecting %u tunnelled messages\n", msg_count);
2573                 if (!msg_count)
2574                         goto exit;
2575         }
2576
2577         /* Receive original message */
2578
2579         if (dest_link->exp_msg_count == 0) {
2580                 warn("Link switchover error, "
2581                      "got too many tunnelled messages\n");
2582                 msg_dbg(tunnel_msg, "OVERDUE/DROP/<REC<");
2583                 dbg_print_link(dest_link, "LINK:");
2584                 goto exit;
2585         }
2586         dest_link->exp_msg_count--;
2587         if (less(msg_seqno(msg), dest_link->reset_checkpoint)) {
2588                 msg_dbg(tunnel_msg, "DROP/DUPL/<REC<");
2589                 goto exit;
2590         } else {
2591                 *buf = buf_extract(tunnel_buf, INT_H_SIZE);
2592                 if (*buf != NULL) {
2593                         msg_dbg(tunnel_msg, "TNL<REC<");
2594                         buf_discard(tunnel_buf);
2595                         return 1;
2596                 } else {
2597                         warn("Link changeover error, original msg dropped\n");
2598                 }
2599         }
2600 exit:
2601         *buf = NULL;
2602         buf_discard(tunnel_buf);
2603         return 0;
2604 }
2605
2606 /*
2607  *  Bundler functionality:
2608  */
2609 void tipc_link_recv_bundle(struct sk_buff *buf)
2610 {
2611         u32 msgcount = msg_msgcnt(buf_msg(buf));
2612         u32 pos = INT_H_SIZE;
2613         struct sk_buff *obuf;
2614
2615         msg_dbg(buf_msg(buf), "<BNDL<: ");
2616         while (msgcount--) {
2617                 obuf = buf_extract(buf, pos);
2618                 if (obuf == NULL) {
2619                         warn("Link unable to unbundle message(s)\n");
2620                         break;
2621                 }
2622                 pos += align(msg_size(buf_msg(obuf)));
2623                 msg_dbg(buf_msg(obuf), "     /");
2624                 tipc_net_route_msg(obuf);
2625         }
2626         buf_discard(buf);
2627 }
2628
2629 /*
2630  *  Fragmentation/defragmentation:
2631  */
2632
2633
2634 /*
2635  * tipc_link_send_long_buf: Entry for buffers needing fragmentation.
2636  * The buffer is complete, inclusive total message length.
2637  * Returns user data length.
2638  */
2639 int tipc_link_send_long_buf(struct link *l_ptr, struct sk_buff *buf)
2640 {
2641         struct tipc_msg *inmsg = buf_msg(buf);
2642         struct tipc_msg fragm_hdr;
2643         u32 insize = msg_size(inmsg);
2644         u32 dsz = msg_data_sz(inmsg);
2645         unchar *crs = buf->data;
2646         u32 rest = insize;
2647         u32 pack_sz = l_ptr->max_pkt;
2648         u32 fragm_sz = pack_sz - INT_H_SIZE;
2649         u32 fragm_no = 1;
2650         u32 destaddr;
2651
2652         if (msg_short(inmsg))
2653                 destaddr = l_ptr->addr;
2654         else
2655                 destaddr = msg_destnode(inmsg);
2656
2657         if (msg_routed(inmsg))
2658                 msg_set_prevnode(inmsg, tipc_own_addr);
2659
2660         /* Prepare reusable fragment header: */
2661
2662         tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
2663                  INT_H_SIZE, destaddr);
2664         msg_set_link_selector(&fragm_hdr, msg_link_selector(inmsg));
2665         msg_set_long_msgno(&fragm_hdr, mod(l_ptr->long_msg_seq_no++));
2666         msg_set_fragm_no(&fragm_hdr, fragm_no);
2667         l_ptr->stats.sent_fragmented++;
2668
2669         /* Chop up message: */
2670
2671         while (rest > 0) {
2672                 struct sk_buff *fragm;
2673
2674                 if (rest <= fragm_sz) {
2675                         fragm_sz = rest;
2676                         msg_set_type(&fragm_hdr, LAST_FRAGMENT);
2677                 }
2678                 fragm = buf_acquire(fragm_sz + INT_H_SIZE);
2679                 if (fragm == NULL) {
2680                         warn("Link unable to fragment message\n");
2681                         dsz = -ENOMEM;
2682                         goto exit;
2683                 }
2684                 msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
2685                 skb_copy_to_linear_data(fragm, &fragm_hdr, INT_H_SIZE);
2686                 skb_copy_to_linear_data_offset(fragm, INT_H_SIZE, crs,
2687                                                fragm_sz);
2688                 /*  Send queued messages first, if any: */
2689
2690                 l_ptr->stats.sent_fragments++;
2691                 tipc_link_send_buf(l_ptr, fragm);
2692                 if (!tipc_link_is_up(l_ptr))
2693                         return dsz;
2694                 msg_set_fragm_no(&fragm_hdr, ++fragm_no);
2695                 rest -= fragm_sz;
2696                 crs += fragm_sz;
2697                 msg_set_type(&fragm_hdr, FRAGMENT);
2698         }
2699 exit:
2700         buf_discard(buf);
2701         return dsz;
2702 }
2703
2704 /*
2705  * A pending message being re-assembled must store certain values
2706  * to handle subsequent fragments correctly. The following functions
2707  * help storing these values in unused, available fields in the
2708  * pending message. This makes dynamic memory allocation unecessary.
2709  */
2710
2711 static void set_long_msg_seqno(struct sk_buff *buf, u32 seqno)
2712 {
2713         msg_set_seqno(buf_msg(buf), seqno);
2714 }
2715
2716 static u32 get_fragm_size(struct sk_buff *buf)
2717 {
2718         return msg_ack(buf_msg(buf));
2719 }
2720
2721 static void set_fragm_size(struct sk_buff *buf, u32 sz)
2722 {
2723         msg_set_ack(buf_msg(buf), sz);
2724 }
2725
2726 static u32 get_expected_frags(struct sk_buff *buf)
2727 {
2728         return msg_bcast_ack(buf_msg(buf));
2729 }
2730
2731 static void set_expected_frags(struct sk_buff *buf, u32 exp)
2732 {
2733         msg_set_bcast_ack(buf_msg(buf), exp);
2734 }
2735
2736 static u32 get_timer_cnt(struct sk_buff *buf)
2737 {
2738         return msg_reroute_cnt(buf_msg(buf));
2739 }
2740
2741 static void incr_timer_cnt(struct sk_buff *buf)
2742 {
2743         msg_incr_reroute_cnt(buf_msg(buf));
2744 }
2745
2746 /*
2747  * tipc_link_recv_fragment(): Called with node lock on. Returns
2748  * the reassembled buffer if message is complete.
2749  */
2750 int tipc_link_recv_fragment(struct sk_buff **pending, struct sk_buff **fb,
2751                             struct tipc_msg **m)
2752 {
2753         struct sk_buff *prev = NULL;
2754         struct sk_buff *fbuf = *fb;
2755         struct tipc_msg *fragm = buf_msg(fbuf);
2756         struct sk_buff *pbuf = *pending;
2757         u32 long_msg_seq_no = msg_long_msgno(fragm);
2758
2759         *fb = NULL;
2760         msg_dbg(fragm,"FRG<REC<");
2761
2762         /* Is there an incomplete message waiting for this fragment? */
2763
2764         while (pbuf && ((msg_seqno(buf_msg(pbuf)) != long_msg_seq_no) ||
2765                         (msg_orignode(fragm) != msg_orignode(buf_msg(pbuf))))) {
2766                 prev = pbuf;
2767                 pbuf = pbuf->next;
2768         }
2769
2770         if (!pbuf && (msg_type(fragm) == FIRST_FRAGMENT)) {
2771                 struct tipc_msg *imsg = (struct tipc_msg *)msg_data(fragm);
2772                 u32 msg_sz = msg_size(imsg);
2773                 u32 fragm_sz = msg_data_sz(fragm);
2774                 u32 exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz);
2775                 u32 max =  TIPC_MAX_USER_MSG_SIZE + LONG_H_SIZE;
2776                 if (msg_type(imsg) == TIPC_MCAST_MSG)
2777                         max = TIPC_MAX_USER_MSG_SIZE + MCAST_H_SIZE;
2778                 if (msg_size(imsg) > max) {
2779                         msg_dbg(fragm,"<REC<Oversized: ");
2780                         buf_discard(fbuf);
2781                         return 0;
2782                 }
2783                 pbuf = buf_acquire(msg_size(imsg));
2784                 if (pbuf != NULL) {
2785                         pbuf->next = *pending;
2786                         *pending = pbuf;
2787                         skb_copy_to_linear_data(pbuf, imsg,
2788                                                 msg_data_sz(fragm));
2789                         /*  Prepare buffer for subsequent fragments. */
2790
2791                         set_long_msg_seqno(pbuf, long_msg_seq_no);
2792                         set_fragm_size(pbuf,fragm_sz);
2793                         set_expected_frags(pbuf,exp_fragm_cnt - 1);
2794                 } else {
2795                         warn("Link unable to reassemble fragmented message\n");
2796                 }
2797                 buf_discard(fbuf);
2798                 return 0;
2799         } else if (pbuf && (msg_type(fragm) != FIRST_FRAGMENT)) {
2800                 u32 dsz = msg_data_sz(fragm);
2801                 u32 fsz = get_fragm_size(pbuf);
2802                 u32 crs = ((msg_fragm_no(fragm) - 1) * fsz);
2803                 u32 exp_frags = get_expected_frags(pbuf) - 1;
2804                 skb_copy_to_linear_data_offset(pbuf, crs,
2805                                                msg_data(fragm), dsz);
2806                 buf_discard(fbuf);
2807
2808                 /* Is message complete? */
2809
2810                 if (exp_frags == 0) {
2811                         if (prev)
2812                                 prev->next = pbuf->next;
2813                         else
2814                                 *pending = pbuf->next;
2815                         msg_reset_reroute_cnt(buf_msg(pbuf));
2816                         *fb = pbuf;
2817                         *m = buf_msg(pbuf);
2818                         return 1;
2819                 }
2820                 set_expected_frags(pbuf,exp_frags);
2821                 return 0;
2822         }
2823         dbg(" Discarding orphan fragment %x\n",fbuf);
2824         msg_dbg(fragm,"ORPHAN:");
2825         dbg("Pending long buffers:\n");
2826         dbg_print_buf_chain(*pending);
2827         buf_discard(fbuf);
2828         return 0;
2829 }
2830
2831 /**
2832  * link_check_defragm_bufs - flush stale incoming message fragments
2833  * @l_ptr: pointer to link
2834  */
2835
2836 static void link_check_defragm_bufs(struct link *l_ptr)
2837 {
2838         struct sk_buff *prev = NULL;
2839         struct sk_buff *next = NULL;
2840         struct sk_buff *buf = l_ptr->defragm_buf;
2841
2842         if (!buf)
2843                 return;
2844         if (!link_working_working(l_ptr))
2845                 return;
2846         while (buf) {
2847                 u32 cnt = get_timer_cnt(buf);
2848
2849                 next = buf->next;
2850                 if (cnt < 4) {
2851                         incr_timer_cnt(buf);
2852                         prev = buf;
2853                 } else {
2854                         dbg(" Discarding incomplete long buffer\n");
2855                         msg_dbg(buf_msg(buf), "LONG:");
2856                         dbg_print_link(l_ptr, "curr:");
2857                         dbg("Pending long buffers:\n");
2858                         dbg_print_buf_chain(l_ptr->defragm_buf);
2859                         if (prev)
2860                                 prev->next = buf->next;
2861                         else
2862                                 l_ptr->defragm_buf = buf->next;
2863                         buf_discard(buf);
2864                 }
2865                 buf = next;
2866         }
2867 }
2868
2869
2870
2871 static void link_set_supervision_props(struct link *l_ptr, u32 tolerance)
2872 {
2873         l_ptr->tolerance = tolerance;
2874         l_ptr->continuity_interval =
2875                 ((tolerance / 4) > 500) ? 500 : tolerance / 4;
2876         l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
2877 }
2878
2879
2880 void tipc_link_set_queue_limits(struct link *l_ptr, u32 window)
2881 {
2882         /* Data messages from this node, inclusive FIRST_FRAGM */
2883         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE] = window;
2884         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE] = (window / 3) * 4;
2885         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE] = (window / 3) * 5;
2886         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE] = (window / 3) * 6;
2887         /* Transiting data messages,inclusive FIRST_FRAGM */
2888         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE + 4] = 300;
2889         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE + 4] = 600;
2890         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE + 4] = 900;
2891         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE + 4] = 1200;
2892         l_ptr->queue_limit[CONN_MANAGER] = 1200;
2893         l_ptr->queue_limit[ROUTE_DISTRIBUTOR] = 1200;
2894         l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
2895         l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
2896         /* FRAGMENT and LAST_FRAGMENT packets */
2897         l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
2898 }
2899
2900 /**
2901  * link_find_link - locate link by name
2902  * @name - ptr to link name string
2903  * @node - ptr to area to be filled with ptr to associated node
2904  *
2905  * Caller must hold 'tipc_net_lock' to ensure node and bearer are not deleted;
2906  * this also prevents link deletion.
2907  *
2908  * Returns pointer to link (or 0 if invalid link name).
2909  */
2910
2911 static struct link *link_find_link(const char *name, struct tipc_node **node)
2912 {
2913         struct link_name link_name_parts;
2914         struct bearer *b_ptr;
2915         struct link *l_ptr;
2916
2917         if (!link_name_validate(name, &link_name_parts))
2918                 return NULL;
2919
2920         b_ptr = tipc_bearer_find_interface(link_name_parts.if_local);
2921         if (!b_ptr)
2922                 return NULL;
2923
2924         *node = tipc_node_find(link_name_parts.addr_peer);
2925         if (!*node)
2926                 return NULL;
2927
2928         l_ptr = (*node)->links[b_ptr->identity];
2929         if (!l_ptr || strcmp(l_ptr->name, name))
2930                 return NULL;
2931
2932         return l_ptr;
2933 }
2934
2935 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2936                                      u16 cmd)
2937 {
2938         struct tipc_link_config *args;
2939         u32 new_value;
2940         struct link *l_ptr;
2941         struct tipc_node *node;
2942         int res;
2943
2944         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2945                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2946
2947         args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2948         new_value = ntohl(args->value);
2949
2950         if (!strcmp(args->name, tipc_bclink_name)) {
2951                 if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2952                     (tipc_bclink_set_queue_limits(new_value) == 0))
2953                         return tipc_cfg_reply_none();
2954                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2955                                                    " (cannot change setting on broadcast link)");
2956         }
2957
2958         read_lock_bh(&tipc_net_lock);
2959         l_ptr = link_find_link(args->name, &node);
2960         if (!l_ptr) {
2961                 read_unlock_bh(&tipc_net_lock);
2962                 return tipc_cfg_reply_error_string("link not found");
2963         }
2964
2965         tipc_node_lock(node);
2966         res = -EINVAL;
2967         switch (cmd) {
2968         case TIPC_CMD_SET_LINK_TOL:
2969                 if ((new_value >= TIPC_MIN_LINK_TOL) &&
2970                     (new_value <= TIPC_MAX_LINK_TOL)) {
2971                         link_set_supervision_props(l_ptr, new_value);
2972                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2973                                                  0, 0, new_value, 0, 0);
2974                         res = 0;
2975                 }
2976                 break;
2977         case TIPC_CMD_SET_LINK_PRI:
2978                 if ((new_value >= TIPC_MIN_LINK_PRI) &&
2979                     (new_value <= TIPC_MAX_LINK_PRI)) {
2980                         l_ptr->priority = new_value;
2981                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2982                                                  0, 0, 0, new_value, 0);
2983                         res = 0;
2984                 }
2985                 break;
2986         case TIPC_CMD_SET_LINK_WINDOW:
2987                 if ((new_value >= TIPC_MIN_LINK_WIN) &&
2988                     (new_value <= TIPC_MAX_LINK_WIN)) {
2989                         tipc_link_set_queue_limits(l_ptr, new_value);
2990                         res = 0;
2991                 }
2992                 break;
2993         }
2994         tipc_node_unlock(node);
2995
2996         read_unlock_bh(&tipc_net_lock);
2997         if (res)
2998                 return tipc_cfg_reply_error_string("cannot change link setting");
2999
3000         return tipc_cfg_reply_none();
3001 }
3002
3003 /**
3004  * link_reset_statistics - reset link statistics
3005  * @l_ptr: pointer to link
3006  */
3007
3008 static void link_reset_statistics(struct link *l_ptr)
3009 {
3010         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
3011         l_ptr->stats.sent_info = l_ptr->next_out_no;
3012         l_ptr->stats.recv_info = l_ptr->next_in_no;
3013 }
3014
3015 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
3016 {
3017         char *link_name;
3018         struct link *l_ptr;
3019         struct tipc_node *node;
3020
3021         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
3022                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
3023
3024         link_name = (char *)TLV_DATA(req_tlv_area);
3025         if (!strcmp(link_name, tipc_bclink_name)) {
3026                 if (tipc_bclink_reset_stats())
3027                         return tipc_cfg_reply_error_string("link not found");
3028                 return tipc_cfg_reply_none();
3029         }
3030
3031         read_lock_bh(&tipc_net_lock);
3032         l_ptr = link_find_link(link_name, &node);
3033         if (!l_ptr) {
3034                 read_unlock_bh(&tipc_net_lock);
3035                 return tipc_cfg_reply_error_string("link not found");
3036         }
3037
3038         tipc_node_lock(node);
3039         link_reset_statistics(l_ptr);
3040         tipc_node_unlock(node);
3041         read_unlock_bh(&tipc_net_lock);
3042         return tipc_cfg_reply_none();
3043 }
3044
3045 /**
3046  * percent - convert count to a percentage of total (rounding up or down)
3047  */
3048
3049 static u32 percent(u32 count, u32 total)
3050 {
3051         return (count * 100 + (total / 2)) / total;
3052 }
3053
3054 /**
3055  * tipc_link_stats - print link statistics
3056  * @name: link name
3057  * @buf: print buffer area
3058  * @buf_size: size of print buffer area
3059  *
3060  * Returns length of print buffer data string (or 0 if error)
3061  */
3062
3063 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
3064 {
3065         struct print_buf pb;
3066         struct link *l_ptr;
3067         struct tipc_node *node;
3068         char *status;
3069         u32 profile_total = 0;
3070
3071         if (!strcmp(name, tipc_bclink_name))
3072                 return tipc_bclink_stats(buf, buf_size);
3073
3074         tipc_printbuf_init(&pb, buf, buf_size);
3075
3076         read_lock_bh(&tipc_net_lock);
3077         l_ptr = link_find_link(name, &node);
3078         if (!l_ptr) {
3079                 read_unlock_bh(&tipc_net_lock);
3080                 return 0;
3081         }
3082         tipc_node_lock(node);
3083
3084         if (tipc_link_is_active(l_ptr))
3085                 status = "ACTIVE";
3086         else if (tipc_link_is_up(l_ptr))
3087                 status = "STANDBY";
3088         else
3089                 status = "DEFUNCT";
3090         tipc_printf(&pb, "Link <%s>\n"
3091                          "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
3092                          "  Window:%u packets\n",
3093                     l_ptr->name, status, l_ptr->max_pkt,
3094                     l_ptr->priority, l_ptr->tolerance, l_ptr->queue_limit[0]);
3095         tipc_printf(&pb, "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
3096                     l_ptr->next_in_no - l_ptr->stats.recv_info,
3097                     l_ptr->stats.recv_fragments,
3098                     l_ptr->stats.recv_fragmented,
3099                     l_ptr->stats.recv_bundles,
3100                     l_ptr->stats.recv_bundled);
3101         tipc_printf(&pb, "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
3102                     l_ptr->next_out_no - l_ptr->stats.sent_info,
3103                     l_ptr->stats.sent_fragments,
3104                     l_ptr->stats.sent_fragmented,
3105                     l_ptr->stats.sent_bundles,
3106                     l_ptr->stats.sent_bundled);
3107         profile_total = l_ptr->stats.msg_length_counts;
3108         if (!profile_total)
3109                 profile_total = 1;
3110         tipc_printf(&pb, "  TX profile sample:%u packets  average:%u octets\n"
3111                          "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
3112                          "-16354:%u%% -32768:%u%% -66000:%u%%\n",
3113                     l_ptr->stats.msg_length_counts,
3114                     l_ptr->stats.msg_lengths_total / profile_total,
3115                     percent(l_ptr->stats.msg_length_profile[0], profile_total),
3116                     percent(l_ptr->stats.msg_length_profile[1], profile_total),
3117                     percent(l_ptr->stats.msg_length_profile[2], profile_total),
3118                     percent(l_ptr->stats.msg_length_profile[3], profile_total),
3119                     percent(l_ptr->stats.msg_length_profile[4], profile_total),
3120                     percent(l_ptr->stats.msg_length_profile[5], profile_total),
3121                     percent(l_ptr->stats.msg_length_profile[6], profile_total));
3122         tipc_printf(&pb, "  RX states:%u probes:%u naks:%u defs:%u dups:%u\n",
3123                     l_ptr->stats.recv_states,
3124                     l_ptr->stats.recv_probes,
3125                     l_ptr->stats.recv_nacks,
3126                     l_ptr->stats.deferred_recv,
3127                     l_ptr->stats.duplicates);
3128         tipc_printf(&pb, "  TX states:%u probes:%u naks:%u acks:%u dups:%u\n",
3129                     l_ptr->stats.sent_states,
3130                     l_ptr->stats.sent_probes,
3131                     l_ptr->stats.sent_nacks,
3132                     l_ptr->stats.sent_acks,
3133                     l_ptr->stats.retransmitted);
3134         tipc_printf(&pb, "  Congestion bearer:%u link:%u  Send queue max:%u avg:%u\n",
3135                     l_ptr->stats.bearer_congs,
3136                     l_ptr->stats.link_congs,
3137                     l_ptr->stats.max_queue_sz,
3138                     l_ptr->stats.queue_sz_counts
3139                     ? (l_ptr->stats.accu_queue_sz / l_ptr->stats.queue_sz_counts)
3140                     : 0);
3141
3142         tipc_node_unlock(node);
3143         read_unlock_bh(&tipc_net_lock);
3144         return tipc_printbuf_validate(&pb);
3145 }
3146
3147 #define MAX_LINK_STATS_INFO 2000
3148
3149 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
3150 {
3151         struct sk_buff *buf;
3152         struct tlv_desc *rep_tlv;
3153         int str_len;
3154
3155         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
3156                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
3157
3158         buf = tipc_cfg_reply_alloc(TLV_SPACE(MAX_LINK_STATS_INFO));
3159         if (!buf)
3160                 return NULL;
3161
3162         rep_tlv = (struct tlv_desc *)buf->data;
3163
3164         str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
3165                                   (char *)TLV_DATA(rep_tlv), MAX_LINK_STATS_INFO);
3166         if (!str_len) {
3167                 buf_discard(buf);
3168                 return tipc_cfg_reply_error_string("link not found");
3169         }
3170
3171         skb_put(buf, TLV_SPACE(str_len));
3172         TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
3173
3174         return buf;
3175 }
3176
3177 #if 0
3178 int link_control(const char *name, u32 op, u32 val)
3179 {
3180         int res = -EINVAL;
3181         struct link *l_ptr;
3182         u32 bearer_id;
3183         struct tipc_node * node;
3184         u32 a;
3185
3186         a = link_name2addr(name, &bearer_id);
3187         read_lock_bh(&tipc_net_lock);
3188         node = tipc_node_find(a);
3189         if (node) {
3190                 tipc_node_lock(node);
3191                 l_ptr = node->links[bearer_id];
3192                 if (l_ptr) {
3193                         if (op == TIPC_REMOVE_LINK) {
3194                                 struct bearer *b_ptr = l_ptr->b_ptr;
3195                                 spin_lock_bh(&b_ptr->publ.lock);
3196                                 tipc_link_delete(l_ptr);
3197                                 spin_unlock_bh(&b_ptr->publ.lock);
3198                         }
3199                         if (op == TIPC_CMD_BLOCK_LINK) {
3200                                 tipc_link_reset(l_ptr);
3201                                 l_ptr->blocked = 1;
3202                         }
3203                         if (op == TIPC_CMD_UNBLOCK_LINK) {
3204                                 l_ptr->blocked = 0;
3205                         }
3206                         res = 0;
3207                 }
3208                 tipc_node_unlock(node);
3209         }
3210         read_unlock_bh(&tipc_net_lock);
3211         return res;
3212 }
3213 #endif
3214
3215 /**
3216  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
3217  * @dest: network address of destination node
3218  * @selector: used to select from set of active links
3219  *
3220  * If no active link can be found, uses default maximum packet size.
3221  */
3222
3223 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
3224 {
3225         struct tipc_node *n_ptr;
3226         struct link *l_ptr;
3227         u32 res = MAX_PKT_DEFAULT;
3228
3229         if (dest == tipc_own_addr)
3230                 return MAX_MSG_SIZE;
3231
3232         read_lock_bh(&tipc_net_lock);
3233         n_ptr = tipc_node_select(dest, selector);
3234         if (n_ptr) {
3235                 tipc_node_lock(n_ptr);
3236                 l_ptr = n_ptr->active_links[selector & 1];
3237                 if (l_ptr)
3238                         res = l_ptr->max_pkt;
3239                 tipc_node_unlock(n_ptr);
3240         }
3241         read_unlock_bh(&tipc_net_lock);
3242         return res;
3243 }
3244
3245 #if 0
3246 static void link_dump_rec_queue(struct link *l_ptr)
3247 {
3248         struct sk_buff *crs;
3249
3250         if (!l_ptr->oldest_deferred_in) {
3251                 info("Reception queue empty\n");
3252                 return;
3253         }
3254         info("Contents of Reception queue:\n");
3255         crs = l_ptr->oldest_deferred_in;
3256         while (crs) {
3257                 if (crs->data == (void *)0x0000a3a3) {
3258                         info("buffer %x invalid\n", crs);
3259                         return;
3260                 }
3261                 msg_dbg(buf_msg(crs), "In rec queue:\n");
3262                 crs = crs->next;
3263         }
3264 }
3265 #endif
3266
3267 static void link_dump_send_queue(struct link *l_ptr)
3268 {
3269         if (l_ptr->next_out) {
3270                 info("\nContents of unsent queue:\n");
3271                 dbg_print_buf_chain(l_ptr->next_out);
3272         }
3273         info("\nContents of send queue:\n");
3274         if (l_ptr->first_out) {
3275                 dbg_print_buf_chain(l_ptr->first_out);
3276         }
3277         info("Empty send queue\n");
3278 }
3279
3280 static void link_print(struct link *l_ptr, struct print_buf *buf,
3281                        const char *str)
3282 {
3283         tipc_printf(buf, str);
3284         if (link_reset_reset(l_ptr) || link_reset_unknown(l_ptr))
3285                 return;
3286         tipc_printf(buf, "Link %x<%s>:",
3287                     l_ptr->addr, l_ptr->b_ptr->publ.name);
3288         tipc_printf(buf, ": NXO(%u):", mod(l_ptr->next_out_no));
3289         tipc_printf(buf, "NXI(%u):", mod(l_ptr->next_in_no));
3290         tipc_printf(buf, "SQUE");
3291         if (l_ptr->first_out) {
3292                 tipc_printf(buf, "[%u..", msg_seqno(buf_msg(l_ptr->first_out)));
3293                 if (l_ptr->next_out)
3294                         tipc_printf(buf, "%u..",
3295                                     msg_seqno(buf_msg(l_ptr->next_out)));
3296                 tipc_printf(buf, "%u]", msg_seqno(buf_msg(l_ptr->last_out)));
3297                 if ((mod(msg_seqno(buf_msg(l_ptr->last_out)) -
3298                          msg_seqno(buf_msg(l_ptr->first_out)))
3299                      != (l_ptr->out_queue_size - 1)) ||
3300                     (l_ptr->last_out->next != NULL)) {
3301                         tipc_printf(buf, "\nSend queue inconsistency\n");
3302                         tipc_printf(buf, "first_out= %x ", l_ptr->first_out);
3303                         tipc_printf(buf, "next_out= %x ", l_ptr->next_out);
3304                         tipc_printf(buf, "last_out= %x ", l_ptr->last_out);
3305                         link_dump_send_queue(l_ptr);
3306                 }
3307         } else
3308                 tipc_printf(buf, "[]");
3309         tipc_printf(buf, "SQSIZ(%u)", l_ptr->out_queue_size);
3310         if (l_ptr->oldest_deferred_in) {
3311                 u32 o = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
3312                 u32 n = msg_seqno(buf_msg(l_ptr->newest_deferred_in));
3313                 tipc_printf(buf, ":RQUE[%u..%u]", o, n);
3314                 if (l_ptr->deferred_inqueue_sz != mod((n + 1) - o)) {
3315                         tipc_printf(buf, ":RQSIZ(%u)",
3316                                     l_ptr->deferred_inqueue_sz);
3317                 }
3318         }
3319         if (link_working_unknown(l_ptr))
3320                 tipc_printf(buf, ":WU");
3321         if (link_reset_reset(l_ptr))
3322                 tipc_printf(buf, ":RR");
3323         if (link_reset_unknown(l_ptr))
3324                 tipc_printf(buf, ":RU");
3325         if (link_working_working(l_ptr))
3326                 tipc_printf(buf, ":WW");
3327         tipc_printf(buf, "\n");
3328 }
3329