net/tipc/link.c

   1 /*
   2  * net/tipc/link.c: TIPC link code
   3  *
   4  * Copyright (c) 1996-2007, Ericsson AB
   5  * Copyright (c) 2004-2007, Wind River Systems
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the names of the copyright holders nor the names of its
  17  *    contributors may be used to endorse or promote products derived from
  18  *    this software without specific prior written permission.
  19  *
  20  * Alternatively, this software may be distributed under the terms of the
  21  * GNU General Public License ("GPL") version 2 as published by the Free
  22  * Software Foundation.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34  * POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include "core.h"
  38 #include "dbg.h"
  39 #include "link.h"
  40 #include "net.h"
  41 #include "node.h"
  42 #include "port.h"
  43 #include "addr.h"
  44 #include "node_subscr.h"
  45 #include "name_distr.h"
  46 #include "bearer.h"
  47 #include "name_table.h"
  48 #include "discover.h"
  49 #include "config.h"
  50 #include "bcast.h"
  51
  52
  53 /*
  54  * 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 int link_working_working(struct link *l_ptr)
 206 {
 207         return (l_ptr->state == WORKING_WORKING);
 208 }
 209
 210 static int link_working_unknown(struct link *l_ptr)
 211 {
 212         return (l_ptr->state == WORKING_UNKNOWN);
 213 }
 214
 215 static int link_reset_unknown(struct link *l_ptr)
 216 {
 217         return (l_ptr->state == RESET_UNKNOWN);
 218 }
 219
 220 static int link_reset_reset(struct link *l_ptr)
 221 {
 222         return (l_ptr->state == RESET_RESET);
 223 }
 224
 225 static int link_blocked(struct link *l_ptr)
 226 {
 227         return (l_ptr->exp_msg_count || l_ptr->blocked);
 228 }
 229
 230 static int link_congested(struct link *l_ptr)
 231 {
 232         return (l_ptr->out_queue_size >= l_ptr->queue_limit[0]);
 233 }
 234
 235 static u32 link_max_pkt(struct link *l_ptr)
 236 {
 237         return l_ptr->max_pkt;
 238 }
 239
 240 static void link_init_max_pkt(struct link *l_ptr)
 241 {
 242         u32 max_pkt;
 243
 244         max_pkt = (l_ptr->b_ptr->publ.mtu & ~3);
 245         if (max_pkt > MAX_MSG_SIZE)
 246                 max_pkt = MAX_MSG_SIZE;
 247
 248         l_ptr->max_pkt_target = max_pkt;
 249         if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
 250                 l_ptr->max_pkt = l_ptr->max_pkt_target;
 251         else
 252                 l_ptr->max_pkt = MAX_PKT_DEFAULT;
 253
 254         l_ptr->max_pkt_probes = 0;
 255 }
 256
 257 static u32 link_next_sent(struct link *l_ptr)
 258 {
 259         if (l_ptr->next_out)
 260                 return msg_seqno(buf_msg(l_ptr->next_out));
 261         return mod(l_ptr->next_out_no);
 262 }
 263
 264 static u32 link_last_sent(struct link *l_ptr)
 265 {
 266         return mod(link_next_sent(l_ptr) - 1);
 267 }
 268
 269 /*
 270  *  Simple non-static link routines (i.e. referenced outside this file)
 271  */
 272
 273 int tipc_link_is_up(struct link *l_ptr)
 274 {
 275         if (!l_ptr)
 276                 return 0;
 277         return (link_working_working(l_ptr) || link_working_unknown(l_ptr));
 278 }
 279
 280 int tipc_link_is_active(struct link *l_ptr)
 281 {
 282         return ((l_ptr->owner->active_links[0] == l_ptr) ||
 283                 (l_ptr->owner->active_links[1] == l_ptr));
 284 }
 285
 286 /**
 287  * link_name_validate - validate & (optionally) deconstruct link name
 288  * @name - ptr to link name string
 289  * @name_parts - ptr to area for link name components (or NULL if not needed)
 290  *
 291  * Returns 1 if link name is valid, otherwise 0.
 292  */
 293
 294 static int link_name_validate(const char *name, struct link_name *name_parts)
 295 {
 296         char name_copy[TIPC_MAX_LINK_NAME];
 297         char *addr_local;
 298         char *if_local;
 299         char *addr_peer;
 300         char *if_peer;
 301         char dummy;
 302         u32 z_local, c_local, n_local;
 303         u32 z_peer, c_peer, n_peer;
 304         u32 if_local_len;
 305         u32 if_peer_len;
 306
 307         /* copy link name & ensure length is OK */
 308
 309         name_copy[TIPC_MAX_LINK_NAME - 1] = 0;
 310         /* need above in case non-Posix strncpy() doesn't pad with nulls */
 311         strncpy(name_copy, name, TIPC_MAX_LINK_NAME);
 312         if (name_copy[TIPC_MAX_LINK_NAME - 1] != 0)
 313                 return 0;
 314
 315         /* ensure all component parts of link name are present */
 316
 317         addr_local = name_copy;
 318         if ((if_local = strchr(addr_local, ':')) == NULL)
 319                 return 0;
 320         *(if_local++) = 0;
 321         if ((addr_peer = strchr(if_local, '-')) == NULL)
 322                 return 0;
 323         *(addr_peer++) = 0;
 324         if_local_len = addr_peer - if_local;
 325         if ((if_peer = strchr(addr_peer, ':')) == NULL)
 326                 return 0;
 327         *(if_peer++) = 0;
 328         if_peer_len = strlen(if_peer) + 1;
 329
 330         /* validate component parts of link name */
 331
 332         if ((sscanf(addr_local, "%u.%u.%u%c",
 333                     &z_local, &c_local, &n_local, &dummy) != 3) ||
 334             (sscanf(addr_peer, "%u.%u.%u%c",
 335                     &z_peer, &c_peer, &n_peer, &dummy) != 3) ||
 336             (z_local > 255) || (c_local > 4095) || (n_local > 4095) ||
 337             (z_peer  > 255) || (c_peer  > 4095) || (n_peer  > 4095) ||
 338             (if_local_len <= 1) || (if_local_len > TIPC_MAX_IF_NAME) ||
 339             (if_peer_len  <= 1) || (if_peer_len  > TIPC_MAX_IF_NAME) ||
 340             (strspn(if_local, tipc_alphabet) != (if_local_len - 1)) ||
 341             (strspn(if_peer, tipc_alphabet) != (if_peer_len - 1)))
 342                 return 0;
 343
 344         /* return link name components, if necessary */
 345
 346         if (name_parts) {
 347                 name_parts->addr_local = tipc_addr(z_local, c_local, n_local);
 348                 strcpy(name_parts->if_local, if_local);
 349                 name_parts->addr_peer = tipc_addr(z_peer, c_peer, n_peer);
 350                 strcpy(name_parts->if_peer, if_peer);
 351         }
 352         return 1;
 353 }
 354
 355 /**
 356  * link_timeout - handle expiration of link timer
 357  * @l_ptr: pointer to link
 358  *
 359  * This routine must not grab "tipc_net_lock" to avoid a potential deadlock conflict
 360  * with tipc_link_delete().  (There is no risk that the node will be deleted by
 361  * another thread because tipc_link_delete() always cancels the link timer before
 362  * tipc_node_delete() is called.)
 363  */
 364
 365 static void link_timeout(struct link *l_ptr)
 366 {
 367         tipc_node_lock(l_ptr->owner);
 368
 369         /* update counters used in statistical profiling of send traffic */
 370
 371         l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
 372         l_ptr->stats.queue_sz_counts++;
 373
 374         if (l_ptr->out_queue_size > l_ptr->stats.max_queue_sz)
 375                 l_ptr->stats.max_queue_sz = l_ptr->out_queue_size;
 376
 377         if (l_ptr->first_out) {
 378                 struct tipc_msg *msg = buf_msg(l_ptr->first_out);
 379                 u32 length = msg_size(msg);
 380
 381                 if ((msg_user(msg) == MSG_FRAGMENTER) &&
 382                     (msg_type(msg) == FIRST_FRAGMENT)) {
 383                         length = msg_size(msg_get_wrapped(msg));
 384                 }
 385                 if (length) {
 386                         l_ptr->stats.msg_lengths_total += length;
 387                         l_ptr->stats.msg_length_counts++;
 388                         if (length <= 64)
 389                                 l_ptr->stats.msg_length_profile[0]++;
 390                         else if (length <= 256)
 391                                 l_ptr->stats.msg_length_profile[1]++;
 392                         else if (length <= 1024)
 393                                 l_ptr->stats.msg_length_profile[2]++;
 394                         else if (length <= 4096)
 395                                 l_ptr->stats.msg_length_profile[3]++;
 396                         else if (length <= 16384)
 397                                 l_ptr->stats.msg_length_profile[4]++;
 398                         else if (length <= 32768)
 399                                 l_ptr->stats.msg_length_profile[5]++;
 400                         else
 401                                 l_ptr->stats.msg_length_profile[6]++;
 402                 }
 403         }
 404
 405         /* do all other link processing performed on a periodic basis */
 406
 407         link_check_defragm_bufs(l_ptr);
 408
 409         link_state_event(l_ptr, TIMEOUT_EVT);
 410
 411         if (l_ptr->next_out)
 412                 tipc_link_push_queue(l_ptr);
 413
 414         tipc_node_unlock(l_ptr->owner);
 415 }
 416
 417 static void link_set_timer(struct link *l_ptr, u32 time)
 418 {
 419         k_start_timer(&l_ptr->timer, time);
 420 }
 421
 422 /**
 423  * tipc_link_create - create a new link
 424  * @b_ptr: pointer to associated bearer
 425  * @peer: network address of node at other end of link
 426  * @media_addr: media address to use when sending messages over link
 427  *
 428  * Returns pointer to link.
 429  */
 430
 431 struct link *tipc_link_create(struct bearer *b_ptr, const u32 peer,
 432                               const struct tipc_media_addr *media_addr)
 433 {
 434         struct link *l_ptr;
 435         struct tipc_msg *msg;
 436         char *if_name;
 437
 438         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 439         if (!l_ptr) {
 440                 warn("Link creation failed, no memory\n");
 441                 return NULL;
 442         }
 443
 444         if (LINK_LOG_BUF_SIZE) {
 445                 char *pb = kmalloc(LINK_LOG_BUF_SIZE, GFP_ATOMIC);
 446
 447                 if (!pb) {
 448                         kfree(l_ptr);
 449                         warn("Link creation failed, no memory for print buffer\n");
 450                         return NULL;
 451                 }
 452                 tipc_printbuf_init(&l_ptr->print_buf, pb, LINK_LOG_BUF_SIZE);
 453         }
 454
 455         l_ptr->addr = peer;
 456         if_name = strchr(b_ptr->publ.name, ':') + 1;
 457         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:",
 458                 tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
 459                 tipc_node(tipc_own_addr),
 460                 if_name,
 461                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 462                 /* note: peer i/f is appended to link name by reset/activate */
 463         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 464         l_ptr->checkpoint = 1;
 465         l_ptr->b_ptr = b_ptr;
 466         link_set_supervision_props(l_ptr, b_ptr->media->tolerance);
 467         l_ptr->state = RESET_UNKNOWN;
 468
 469         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 470         msg = l_ptr->pmsg;
 471         msg_init(msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, l_ptr->addr);
 472         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 473         msg_set_session(msg, (tipc_random & 0xffff));
 474         msg_set_bearer_id(msg, b_ptr->identity);
 475         strcpy((char *)msg_data(msg), if_name);
 476
 477         l_ptr->priority = b_ptr->priority;
 478         tipc_link_set_queue_limits(l_ptr, b_ptr->media->window);
 479
 480         link_init_max_pkt(l_ptr);
 481
 482         l_ptr->next_out_no = 1;
 483         INIT_LIST_HEAD(&l_ptr->waiting_ports);
 484
 485         link_reset_statistics(l_ptr);
 486
 487         l_ptr->owner = tipc_node_attach_link(l_ptr);
 488         if (!l_ptr->owner) {
 489                 if (LINK_LOG_BUF_SIZE)
 490                         kfree(l_ptr->print_buf.buf);
 491                 kfree(l_ptr);
 492                 return NULL;
 493         }
 494
 495         k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
 496         list_add_tail(&l_ptr->link_list, &b_ptr->links);
 497         tipc_k_signal((Handler)tipc_link_start, (unsigned long)l_ptr);
 498
 499         dbg("tipc_link_create(): tolerance = %u,cont intv = %u, abort_limit = %u\n",
 500             l_ptr->tolerance, l_ptr->continuity_interval, l_ptr->abort_limit);
 501
 502         return l_ptr;
 503 }
 504
 505 /**
 506  * tipc_link_delete - delete a link
 507  * @l_ptr: pointer to link
 508  *
 509  * Note: 'tipc_net_lock' is write_locked, bearer is locked.
 510  * This routine must not grab the node lock until after link timer cancellation
 511  * to avoid a potential deadlock situation.
 512  */
 513
 514 void tipc_link_delete(struct link *l_ptr)
 515 {
 516         if (!l_ptr) {
 517                 err("Attempt to delete non-existent link\n");
 518                 return;
 519         }
 520
 521         dbg("tipc_link_delete()\n");
 522
 523         k_cancel_timer(&l_ptr->timer);
 524
 525         tipc_node_lock(l_ptr->owner);
 526         tipc_link_reset(l_ptr);
 527         tipc_node_detach_link(l_ptr->owner, l_ptr);
 528         tipc_link_stop(l_ptr);
 529         list_del_init(&l_ptr->link_list);
 530         if (LINK_LOG_BUF_SIZE)
 531                 kfree(l_ptr->print_buf.buf);
 532         tipc_node_unlock(l_ptr->owner);
 533         k_term_timer(&l_ptr->timer);
 534         kfree(l_ptr);
 535 }
 536
 537 void tipc_link_start(struct link *l_ptr)
 538 {
 539         dbg("tipc_link_start %x\n", l_ptr);
 540         link_state_event(l_ptr, STARTING_EVT);
 541 }
 542
 543 /**
 544  * link_schedule_port - schedule port for deferred sending
 545  * @l_ptr: pointer to link
 546  * @origport: reference to sending port
 547  * @sz: amount of data to be sent
 548  *
 549  * Schedules port for renewed sending of messages after link congestion
 550  * has abated.
 551  */
 552
 553 static int link_schedule_port(struct link *l_ptr, u32 origport, u32 sz)
 554 {
 555         struct port *p_ptr;
 556
 557         spin_lock_bh(&tipc_port_list_lock);
 558         p_ptr = tipc_port_lock(origport);
 559         if (p_ptr) {
 560                 if (!p_ptr->wakeup)
 561                         goto exit;
 562                 if (!list_empty(&p_ptr->wait_list))
 563                         goto exit;
 564                 p_ptr->congested_link = l_ptr;
 565                 p_ptr->publ.congested = 1;
 566                 p_ptr->waiting_pkts = 1 + ((sz - 1) / link_max_pkt(l_ptr));
 567                 list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
 568                 l_ptr->stats.link_congs++;
 569 exit:
 570                 tipc_port_unlock(p_ptr);
 571         }
 572         spin_unlock_bh(&tipc_port_list_lock);
 573         return -ELINKCONG;
 574 }
 575
 576 void tipc_link_wakeup_ports(struct link *l_ptr, int all)
 577 {
 578         struct port *p_ptr;
 579         struct port *temp_p_ptr;
 580         int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;
 581
 582         if (all)
 583                 win = 100000;
 584         if (win <= 0)
 585                 return;
 586         if (!spin_trylock_bh(&tipc_port_list_lock))
 587                 return;
 588         if (link_congested(l_ptr))
 589                 goto exit;
 590         list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
 591                                  wait_list) {
 592                 if (win <= 0)
 593                         break;
 594                 list_del_init(&p_ptr->wait_list);
 595                 p_ptr->congested_link = NULL;
 596                 spin_lock_bh(p_ptr->publ.lock);
 597                 p_ptr->publ.congested = 0;
 598                 p_ptr->wakeup(&p_ptr->publ);
 599                 win -= p_ptr->waiting_pkts;
 600                 spin_unlock_bh(p_ptr->publ.lock);
 601         }
 602
 603 exit:
 604         spin_unlock_bh(&tipc_port_list_lock);
 605 }
 606
 607 /**
 608  * link_release_outqueue - purge link's outbound message queue
 609  * @l_ptr: pointer to link
 610  */
 611
 612 static void link_release_outqueue(struct link *l_ptr)
 613 {
 614         struct sk_buff *buf = l_ptr->first_out;
 615         struct sk_buff *next;
 616
 617         while (buf) {
 618                 next = buf->next;
 619                 buf_discard(buf);
 620                 buf = next;
 621         }
 622         l_ptr->first_out = NULL;
 623         l_ptr->out_queue_size = 0;
 624 }
 625
 626 /**
 627  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 628  * @l_ptr: pointer to link
 629  */
 630
 631 void tipc_link_reset_fragments(struct link *l_ptr)
 632 {
 633         struct sk_buff *buf = l_ptr->defragm_buf;
 634         struct sk_buff *next;
 635
 636         while (buf) {
 637                 next = buf->next;
 638                 buf_discard(buf);
 639                 buf = next;
 640         }
 641         l_ptr->defragm_buf = NULL;
 642 }
 643
 644 /**
 645  * tipc_link_stop - purge all inbound and outbound messages associated with link
 646  * @l_ptr: pointer to link
 647  */
 648
 649 void tipc_link_stop(struct link *l_ptr)
 650 {
 651         struct sk_buff *buf;
 652         struct sk_buff *next;
 653
 654         buf = l_ptr->oldest_deferred_in;
 655         while (buf) {
 656                 next = buf->next;
 657                 buf_discard(buf);
 658                 buf = next;
 659         }
 660
 661         buf = l_ptr->first_out;
 662         while (buf) {
 663                 next = buf->next;
 664                 buf_discard(buf);
 665                 buf = next;
 666         }
 667
 668         tipc_link_reset_fragments(l_ptr);
 669
 670         buf_discard(l_ptr->proto_msg_queue);
 671         l_ptr->proto_msg_queue = NULL;
 672 }
 673
 674 #if 0
 675
 676 /* LINK EVENT CODE IS NOT SUPPORTED AT PRESENT */
 677
 678 static void link_recv_event(struct link_event *ev)
 679 {
 680         ev->fcn(ev->addr, ev->name, ev->up);
 681         kfree(ev);
 682 }
 683
 684 static void link_send_event(void (*fcn)(u32 a, char *n, int up),
 685                             struct link *l_ptr, int up)
 686 {
 687         struct link_event *ev;
 688
 689         ev = kmalloc(sizeof(*ev), GFP_ATOMIC);
 690         if (!ev) {
 691                 warn("Link event allocation failure\n");
 692                 return;
 693         }
 694         ev->addr = l_ptr->addr;
 695         ev->up = up;
 696         ev->fcn = fcn;
 697         memcpy(ev->name, l_ptr->name, TIPC_MAX_LINK_NAME);
 698         tipc_k_signal((Handler)link_recv_event, (unsigned long)ev);
 699 }
 700
 701 #else
 702
 703 #define link_send_event(fcn, l_ptr, up) do { } while (0)
 704
 705 #endif
 706
 707 void tipc_link_reset(struct link *l_ptr)
 708 {
 709         struct sk_buff *buf;
 710         u32 prev_state = l_ptr->state;
 711         u32 checkpoint = l_ptr->next_in_no;
 712         int was_active_link = tipc_link_is_active(l_ptr);
 713
 714         msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
 715
 716         /* Link is down, accept any session */
 717         l_ptr->peer_session = INVALID_SESSION;
 718
 719         /* Prepare for max packet size negotiation */
 720         link_init_max_pkt(l_ptr);
 721
 722         l_ptr->state = RESET_UNKNOWN;
 723         dbg_link_state("Resetting Link\n");
 724
 725         if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
 726                 return;
 727
 728         tipc_node_link_down(l_ptr->owner, l_ptr);
 729         tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
 730 #if 0
 731         tipc_printf(TIPC_CONS, "\nReset link <%s>\n", l_ptr->name);
 732         dbg_link_dump();
 733 #endif
 734         if (was_active_link && tipc_node_has_active_links(l_ptr->owner) &&
 735             l_ptr->owner->permit_changeover) {
 736                 l_ptr->reset_checkpoint = checkpoint;
 737                 l_ptr->exp_msg_count = START_CHANGEOVER;
 738         }
 739
 740         /* Clean up all queues: */
 741
 742         link_release_outqueue(l_ptr);
 743         buf_discard(l_ptr->proto_msg_queue);
 744         l_ptr->proto_msg_queue = NULL;
 745         buf = l_ptr->oldest_deferred_in;
 746         while (buf) {
 747                 struct sk_buff *next = buf->next;
 748                 buf_discard(buf);
 749                 buf = next;
 750         }
 751         if (!list_empty(&l_ptr->waiting_ports))
 752                 tipc_link_wakeup_ports(l_ptr, 1);
 753
 754         l_ptr->retransm_queue_head = 0;
 755         l_ptr->retransm_queue_size = 0;
 756         l_ptr->last_out = NULL;
 757         l_ptr->first_out = NULL;
 758         l_ptr->next_out = NULL;
 759         l_ptr->unacked_window = 0;
 760         l_ptr->checkpoint = 1;
 761         l_ptr->next_out_no = 1;
 762         l_ptr->deferred_inqueue_sz = 0;
 763         l_ptr->oldest_deferred_in = NULL;
 764         l_ptr->newest_deferred_in = NULL;
 765         l_ptr->fsm_msg_cnt = 0;
 766         l_ptr->stale_count = 0;
 767         link_reset_statistics(l_ptr);
 768
 769         link_send_event(tipc_cfg_link_event, l_ptr, 0);
 770         if (!in_own_cluster(l_ptr->addr))
 771                 link_send_event(tipc_disc_link_event, l_ptr, 0);
 772 }
 773
 774
 775 static void link_activate(struct link *l_ptr)
 776 {
 777         l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
 778         tipc_node_link_up(l_ptr->owner, l_ptr);
 779         tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
 780         link_send_event(tipc_cfg_link_event, l_ptr, 1);
 781         if (!in_own_cluster(l_ptr->addr))
 782                 link_send_event(tipc_disc_link_event, l_ptr, 1);
 783 }
 784
 785 /**
 786  * link_state_event - link finite state machine
 787  * @l_ptr: pointer to link
 788  * @event: state machine event to process
 789  */
 790
 791 static void link_state_event(struct link *l_ptr, unsigned event)
 792 {
 793         struct link *other;
 794         u32 cont_intv = l_ptr->continuity_interval;
 795
 796         if (!l_ptr->started && (event != STARTING_EVT))
 797                 return;         /* Not yet. */
 798
 799         if (link_blocked(l_ptr)) {
 800                 if (event == TIMEOUT_EVT) {
 801                         link_set_timer(l_ptr, cont_intv);
 802                 }
 803                 return;   /* Changeover going on */
 804         }
 805         dbg_link("STATE_EV: <%s> ", l_ptr->name);
 806
 807         switch (l_ptr->state) {
 808         case WORKING_WORKING:
 809                 dbg_link("WW/");
 810                 switch (event) {
 811                 case TRAFFIC_MSG_EVT:
 812                         dbg_link("TRF-");
 813                         /* fall through */
 814                 case ACTIVATE_MSG:
 815                         dbg_link("ACT\n");
 816                         break;
 817                 case TIMEOUT_EVT:
 818                         dbg_link("TIM ");
 819                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 820                                 l_ptr->checkpoint = l_ptr->next_in_no;
 821                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 822                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 823                                                                  0, 0, 0, 0, 0);
 824                                         l_ptr->fsm_msg_cnt++;
 825                                 } else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
 826                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 827                                                                  1, 0, 0, 0, 0);
 828                                         l_ptr->fsm_msg_cnt++;
 829                                 }
 830                                 link_set_timer(l_ptr, cont_intv);
 831                                 break;
 832                         }
 833                         dbg_link(" -> WU\n");
 834                         l_ptr->state = WORKING_UNKNOWN;
 835                         l_ptr->fsm_msg_cnt = 0;
 836                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 837                         l_ptr->fsm_msg_cnt++;
 838                         link_set_timer(l_ptr, cont_intv / 4);
 839                         break;
 840                 case RESET_MSG:
 841                         dbg_link("RES -> RR\n");
 842                         info("Resetting link <%s>, requested by peer\n",
 843                              l_ptr->name);
 844                         tipc_link_reset(l_ptr);
 845                         l_ptr->state = RESET_RESET;
 846                         l_ptr->fsm_msg_cnt = 0;
 847                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 848                         l_ptr->fsm_msg_cnt++;
 849                         link_set_timer(l_ptr, cont_intv);
 850                         break;
 851                 default:
 852                         err("Unknown link event %u in WW state\n", event);
 853                 }
 854                 break;
 855         case WORKING_UNKNOWN:
 856                 dbg_link("WU/");
 857                 switch (event) {
 858                 case TRAFFIC_MSG_EVT:
 859                         dbg_link("TRF-");
 860                 case ACTIVATE_MSG:
 861                         dbg_link("ACT -> WW\n");
 862                         l_ptr->state = WORKING_WORKING;
 863                         l_ptr->fsm_msg_cnt = 0;
 864                         link_set_timer(l_ptr, cont_intv);
 865                         break;
 866                 case RESET_MSG:
 867                         dbg_link("RES -> RR\n");
 868                         info("Resetting link <%s>, requested by peer "
 869                              "while probing\n", l_ptr->name);
 870                         tipc_link_reset(l_ptr);
 871                         l_ptr->state = RESET_RESET;
 872                         l_ptr->fsm_msg_cnt = 0;
 873                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 874                         l_ptr->fsm_msg_cnt++;
 875                         link_set_timer(l_ptr, cont_intv);
 876                         break;
 877                 case TIMEOUT_EVT:
 878                         dbg_link("TIM ");
 879                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 880                                 dbg_link("-> WW \n");
 881                                 l_ptr->state = WORKING_WORKING;
 882                                 l_ptr->fsm_msg_cnt = 0;
 883                                 l_ptr->checkpoint = l_ptr->next_in_no;
 884                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 885                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 886                                                                  0, 0, 0, 0, 0);
 887                                         l_ptr->fsm_msg_cnt++;
 888                                 }
 889                                 link_set_timer(l_ptr, cont_intv);
 890                         } else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
 891                                 dbg_link("Probing %u/%u,timer = %u ms)\n",
 892                                          l_ptr->fsm_msg_cnt, l_ptr->abort_limit,
 893                                          cont_intv / 4);
 894                                 tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 895                                                          1, 0, 0, 0, 0);
 896                                 l_ptr->fsm_msg_cnt++;
 897                                 link_set_timer(l_ptr, cont_intv / 4);
 898                         } else {        /* Link has failed */
 899                                 dbg_link("-> RU (%u probes unanswered)\n",
 900                                          l_ptr->fsm_msg_cnt);
 901                                 warn("Resetting link <%s>, peer not responding\n",
 902                                      l_ptr->name);
 903                                 tipc_link_reset(l_ptr);
 904                                 l_ptr->state = RESET_UNKNOWN;
 905                                 l_ptr->fsm_msg_cnt = 0;
 906                                 tipc_link_send_proto_msg(l_ptr, RESET_MSG,
 907                                                          0, 0, 0, 0, 0);
 908                                 l_ptr->fsm_msg_cnt++;
 909                                 link_set_timer(l_ptr, cont_intv);
 910                         }
 911                         break;
 912                 default:
 913                         err("Unknown link event %u in WU state\n", event);
 914                 }
 915                 break;
 916         case RESET_UNKNOWN:
 917                 dbg_link("RU/");
 918                 switch (event) {
 919                 case TRAFFIC_MSG_EVT:
 920                         dbg_link("TRF-\n");
 921                         break;
 922                 case ACTIVATE_MSG:
 923                         other = l_ptr->owner->active_links[0];
 924                         if (other && link_working_unknown(other)) {
 925                                 dbg_link("ACT\n");
 926                                 break;
 927                         }
 928                         dbg_link("ACT -> WW\n");
 929                         l_ptr->state = WORKING_WORKING;
 930                         l_ptr->fsm_msg_cnt = 0;
 931                         link_activate(l_ptr);
 932                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 933                         l_ptr->fsm_msg_cnt++;
 934                         link_set_timer(l_ptr, cont_intv);
 935                         break;
 936                 case RESET_MSG:
 937                         dbg_link("RES \n");
 938                         dbg_link(" -> RR\n");
 939                         l_ptr->state = RESET_RESET;
 940                         l_ptr->fsm_msg_cnt = 0;
 941                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
 942                         l_ptr->fsm_msg_cnt++;
 943                         link_set_timer(l_ptr, cont_intv);
 944                         break;
 945                 case STARTING_EVT:
 946                         dbg_link("START-");
 947                         l_ptr->started = 1;
 948                         /* fall through */
 949                 case TIMEOUT_EVT:
 950                         dbg_link("TIM \n");
 951                         tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
 952                         l_ptr->fsm_msg_cnt++;
 953                         link_set_timer(l_ptr, cont_intv);
 954                         break;
 955                 default:
 956                         err("Unknown link event %u in RU state\n", event);
 957                 }
 958                 break;
 959         case RESET_RESET:
 960                 dbg_link("RR/ ");
 961                 switch (event) {
 962                 case TRAFFIC_MSG_EVT:
 963                         dbg_link("TRF-");
 964                         /* fall through */
 965                 case ACTIVATE_MSG:
 966                         other = l_ptr->owner->active_links[0];
 967                         if (other && link_working_unknown(other)) {
 968                                 dbg_link("ACT\n");
 969                                 break;
 970                         }
 971                         dbg_link("ACT -> WW\n");
 972                         l_ptr->state = WORKING_WORKING;
 973                         l_ptr->fsm_msg_cnt = 0;
 974                         link_activate(l_ptr);
 975                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 976                         l_ptr->fsm_msg_cnt++;
 977                         link_set_timer(l_ptr, cont_intv);
 978                         break;
 979                 case RESET_MSG:
 980                         dbg_link("RES\n");
 981                         break;
 982                 case TIMEOUT_EVT:
 983                         dbg_link("TIM\n");
 984                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 985                         l_ptr->fsm_msg_cnt++;
 986                         link_set_timer(l_ptr, cont_intv);
 987                         dbg_link("fsm_msg_cnt %u\n", l_ptr->fsm_msg_cnt);
 988                         break;
 989                 default:
 990                         err("Unknown link event %u in RR state\n", event);
 991                 }
 992                 break;
 993         default:
 994                 err("Unknown link state %u/%u\n", l_ptr->state, event);
 995         }
 996 }
 997
 998 /*
 999  * link_bundle_buf(): Append contents of a buffer to
1000  * the tail of an existing one.
1001  */
1002
1003 static int link_bundle_buf(struct link *l_ptr,
1004                            struct sk_buff *bundler,
1005                            struct sk_buff *buf)
1006 {
1007         struct tipc_msg *bundler_msg = buf_msg(bundler);
1008         struct tipc_msg *msg = buf_msg(buf);
1009         u32 size = msg_size(msg);
1010         u32 bundle_size = msg_size(bundler_msg);
1011         u32 to_pos = align(bundle_size);
1012         u32 pad = to_pos - bundle_size;
1013
1014         if (msg_user(bundler_msg) != MSG_BUNDLER)
1015                 return 0;
1016         if (msg_type(bundler_msg) != OPEN_MSG)
1017                 return 0;
1018         if (skb_tailroom(bundler) < (pad + size))
1019                 return 0;
1020         if (link_max_pkt(l_ptr) < (to_pos + size))
1021                 return 0;
1022
1023         skb_put(bundler, pad + size);
1024         skb_copy_to_linear_data_offset(bundler, to_pos, buf->data, size);
1025         msg_set_size(bundler_msg, to_pos + size);
1026         msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
1027         dbg("Packed msg # %u(%u octets) into pos %u in buf(#%u)\n",
1028             msg_msgcnt(bundler_msg), size, to_pos, msg_seqno(bundler_msg));
1029         msg_dbg(msg, "PACKD:");
1030         buf_discard(buf);
1031         l_ptr->stats.sent_bundled++;
1032         return 1;
1033 }
1034
1035 static void link_add_to_outqueue(struct link *l_ptr,
1036                                  struct sk_buff *buf,
1037                                  struct tipc_msg *msg)
1038 {
1039         u32 ack = mod(l_ptr->next_in_no - 1);
1040         u32 seqno = mod(l_ptr->next_out_no++);
1041
1042         msg_set_word(msg, 2, ((ack << 16) | seqno));
1043         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1044         buf->next = NULL;
1045         if (l_ptr->first_out) {
1046                 l_ptr->last_out->next = buf;
1047                 l_ptr->last_out = buf;
1048         } else
1049                 l_ptr->first_out = l_ptr->last_out = buf;
1050         l_ptr->out_queue_size++;
1051 }
1052
1053 /*
1054  * tipc_link_send_buf() is the 'full path' for messages, called from
1055  * inside TIPC when the 'fast path' in tipc_send_buf
1056  * has failed, and from link_send()
1057  */
1058
1059 int tipc_link_send_buf(struct link *l_ptr, struct sk_buff *buf)
1060 {
1061         struct tipc_msg *msg = buf_msg(buf);
1062         u32 size = msg_size(msg);
1063         u32 dsz = msg_data_sz(msg);
1064         u32 queue_size = l_ptr->out_queue_size;
1065         u32 imp = msg_tot_importance(msg);
1066         u32 queue_limit = l_ptr->queue_limit[imp];
1067         u32 max_packet = link_max_pkt(l_ptr);
1068
1069         msg_set_prevnode(msg, tipc_own_addr);   /* If routed message */
1070
1071         /* Match msg importance against queue limits: */
1072
1073         if (unlikely(queue_size >= queue_limit)) {
1074                 if (imp <= TIPC_CRITICAL_IMPORTANCE) {
1075                         return link_schedule_port(l_ptr, msg_origport(msg),
1076                                                   size);
1077                 }
1078                 msg_dbg(msg, "TIPC: Congestion, throwing away\n");
1079                 buf_discard(buf);
1080                 if (imp > CONN_MANAGER) {
1081                         warn("Resetting link <%s>, send queue full", l_ptr->name);
1082                         tipc_link_reset(l_ptr);
1083                 }
1084                 return dsz;
1085         }
1086
1087         /* Fragmentation needed ? */
1088
1089         if (size > max_packet)
1090                 return tipc_link_send_long_buf(l_ptr, buf);
1091
1092         /* Packet can be queued or sent: */
1093
1094         if (queue_size > l_ptr->stats.max_queue_sz)
1095                 l_ptr->stats.max_queue_sz = queue_size;
1096
1097         if (likely(!tipc_bearer_congested(l_ptr->b_ptr, l_ptr) &&
1098                    !link_congested(l_ptr))) {
1099                 link_add_to_outqueue(l_ptr, buf, msg);
1100
1101                 if (likely(tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr))) {
1102                         l_ptr->unacked_window = 0;
1103                 } else {
1104                         tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1105                         l_ptr->stats.bearer_congs++;
1106                         l_ptr->next_out = buf;
1107                 }
1108                 return dsz;
1109         }
1110         /* Congestion: can message be bundled ?: */
1111
1112         if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
1113             (msg_user(msg) != MSG_FRAGMENTER)) {
1114
1115                 /* Try adding message to an existing bundle */
1116
1117                 if (l_ptr->next_out &&
1118                     link_bundle_buf(l_ptr, l_ptr->last_out, buf)) {
1119                         tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
1120                         return dsz;
1121                 }
1122
1123                 /* Try creating a new bundle */
1124
1125                 if (size <= max_packet * 2 / 3) {
1126                         struct sk_buff *bundler = buf_acquire(max_packet);
1127                         struct tipc_msg bundler_hdr;
1128
1129                         if (bundler) {
1130                                 msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
1131                                          INT_H_SIZE, l_ptr->addr);
1132                                 skb_copy_to_linear_data(bundler, &bundler_hdr,
1133                                                         INT_H_SIZE);
1134                                 skb_trim(bundler, INT_H_SIZE);
1135                                 link_bundle_buf(l_ptr, bundler, buf);
1136                                 buf = bundler;
1137                                 msg = buf_msg(buf);
1138                                 l_ptr->stats.sent_bundles++;
1139                         }
1140                 }
1141         }
1142         if (!l_ptr->next_out)
1143                 l_ptr->next_out = buf;
1144         link_add_to_outqueue(l_ptr, buf, msg);
1145         tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
1146         return dsz;
1147 }
1148
1149 /*
1150  * tipc_link_send(): same as tipc_link_send_buf(), but the link to use has
1151  * not been selected yet, and the the owner node is not locked
1152  * Called by TIPC internal users, e.g. the name distributor
1153  */
1154
1155 int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector)
1156 {
1157         struct link *l_ptr;
1158         struct tipc_node *n_ptr;
1159         int res = -ELINKCONG;
1160
1161         read_lock_bh(&tipc_net_lock);
1162         n_ptr = tipc_node_select(dest, selector);
1163         if (n_ptr) {
1164                 tipc_node_lock(n_ptr);
1165                 l_ptr = n_ptr->active_links[selector & 1];
1166                 if (l_ptr) {
1167                         dbg("tipc_link_send: found link %x for dest %x\n", l_ptr, dest);
1168                         res = tipc_link_send_buf(l_ptr, buf);
1169                 } else {
1170                         dbg("Attempt to send msg to unreachable node:\n");
1171                         msg_dbg(buf_msg(buf),">>>");
1172                         buf_discard(buf);
1173                 }
1174                 tipc_node_unlock(n_ptr);
1175         } else {
1176                 dbg("Attempt to send msg to unknown node:\n");
1177                 msg_dbg(buf_msg(buf),">>>");
1178                 buf_discard(buf);
1179         }
1180         read_unlock_bh(&tipc_net_lock);
1181         return res;
1182 }
1183
1184 /*
1185  * link_send_buf_fast: Entry for data messages where the
1186  * destination link is known and the header is complete,
1187  * inclusive total message length. Very time critical.
1188  * Link is locked. Returns user data length.
1189  */
1190
1191 static int link_send_buf_fast(struct link *l_ptr, struct sk_buff *buf,
1192                               u32 *used_max_pkt)
1193 {
1194         struct tipc_msg *msg = buf_msg(buf);
1195         int res = msg_data_sz(msg);
1196
1197         if (likely(!link_congested(l_ptr))) {
1198                 if (likely(msg_size(msg) <= link_max_pkt(l_ptr))) {
1199                         if (likely(list_empty(&l_ptr->b_ptr->cong_links))) {
1200                                 link_add_to_outqueue(l_ptr, buf, msg);
1201                                 if (likely(tipc_bearer_send(l_ptr->b_ptr, buf,
1202                                                             &l_ptr->media_addr))) {
1203                                         l_ptr->unacked_window = 0;
1204                                         msg_dbg(msg,"SENT_FAST:");
1205                                         return res;
1206                                 }
1207                                 dbg("failed sent fast...\n");
1208                                 tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1209                                 l_ptr->stats.bearer_congs++;
1210                                 l_ptr->next_out = buf;
1211                                 return res;
1212                         }
1213                 }
1214                 else
1215                         *used_max_pkt = link_max_pkt(l_ptr);
1216         }
1217         return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
1218 }
1219
1220 /*
1221  * tipc_send_buf_fast: Entry for data messages where the
1222  * destination node is known and the header is complete,
1223  * inclusive total message length.
1224  * Returns user data length.
1225  */
1226 int tipc_send_buf_fast(struct sk_buff *buf, u32 destnode)
1227 {
1228         struct link *l_ptr;
1229         struct tipc_node *n_ptr;
1230         int res;
1231         u32 selector = msg_origport(buf_msg(buf)) & 1;
1232         u32 dummy;
1233
1234         if (destnode == tipc_own_addr)
1235                 return tipc_port_recv_msg(buf);
1236
1237         read_lock_bh(&tipc_net_lock);
1238         n_ptr = tipc_node_select(destnode, selector);
1239         if (likely(n_ptr)) {
1240                 tipc_node_lock(n_ptr);
1241                 l_ptr = n_ptr->active_links[selector];
1242                 dbg("send_fast: buf %x selected %x, destnode = %x\n",
1243                     buf, l_ptr, destnode);
1244                 if (likely(l_ptr)) {
1245                         res = link_send_buf_fast(l_ptr, buf, &dummy);
1246                         tipc_node_unlock(n_ptr);
1247                         read_unlock_bh(&tipc_net_lock);
1248                         return res;
1249                 }
1250                 tipc_node_unlock(n_ptr);
1251         }
1252         read_unlock_bh(&tipc_net_lock);
1253         res = msg_data_sz(buf_msg(buf));
1254         tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1255         return res;
1256 }
1257
1258
1259 /*
1260  * tipc_link_send_sections_fast: Entry for messages where the
1261  * destination processor is known and the header is complete,
1262  * except for total message length.
1263  * Returns user data length or errno.
1264  */
1265 int tipc_link_send_sections_fast(struct port *sender,
1266                                  struct iovec const *msg_sect,
1267                                  const u32 num_sect,
1268                                  u32 destaddr)
1269 {
1270         struct tipc_msg *hdr = &sender->publ.phdr;
1271         struct link *l_ptr;
1272         struct sk_buff *buf;
1273         struct tipc_node *node;
1274         int res;
1275         u32 selector = msg_origport(hdr) & 1;
1276
1277 again:
1278         /*
1279          * Try building message using port's max_pkt hint.
1280          * (Must not hold any locks while building message.)
1281          */
1282
1283         res = msg_build(hdr, msg_sect, num_sect, sender->publ.max_pkt,
1284                         !sender->user_port, &buf);
1285
1286         read_lock_bh(&tipc_net_lock);
1287         node = tipc_node_select(destaddr, selector);
1288         if (likely(node)) {
1289                 tipc_node_lock(node);
1290                 l_ptr = node->active_links[selector];
1291                 if (likely(l_ptr)) {
1292                         if (likely(buf)) {
1293                                 res = link_send_buf_fast(l_ptr, buf,
1294                                                          &sender->publ.max_pkt);
1295                                 if (unlikely(res < 0))
1296                                         buf_discard(buf);
1297 exit:
1298                                 tipc_node_unlock(node);
1299                                 read_unlock_bh(&tipc_net_lock);
1300                                 return res;
1301                         }
1302
1303                         /* Exit if build request was invalid */
1304
1305                         if (unlikely(res < 0))
1306                                 goto exit;
1307
1308                         /* Exit if link (or bearer) is congested */
1309
1310                         if (link_congested(l_ptr) ||
1311                             !list_empty(&l_ptr->b_ptr->cong_links)) {
1312                                 res = link_schedule_port(l_ptr,
1313                                                          sender->publ.ref, res);
1314                                 goto exit;
1315                         }
1316
1317                         /*
1318                          * Message size exceeds max_pkt hint; update hint,
1319                          * then re-try fast path or fragment the message
1320                          */
1321
1322                         sender->publ.max_pkt = link_max_pkt(l_ptr);
1323                         tipc_node_unlock(node);
1324                         read_unlock_bh(&tipc_net_lock);
1325
1326
1327                         if ((msg_hdr_sz(hdr) + res) <= sender->publ.max_pkt)
1328                                 goto again;
1329
1330                         return link_send_sections_long(sender, msg_sect,
1331                                                        num_sect, destaddr);
1332                 }
1333                 tipc_node_unlock(node);
1334         }
1335         read_unlock_bh(&tipc_net_lock);
1336
1337         /* Couldn't find a link to the destination node */
1338
1339         if (buf)
1340                 return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1341         if (res >= 0)
1342                 return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1343                                                  TIPC_ERR_NO_NODE);
1344         return res;
1345 }
1346
1347 /*
1348  * link_send_sections_long(): Entry for long messages where the
1349  * destination node is known and the header is complete,
1350  * inclusive total message length.
1351  * Link and bearer congestion status have been checked to be ok,
1352  * and are ignored if they change.
1353  *
1354  * Note that fragments do not use the full link MTU so that they won't have
1355  * to undergo refragmentation if link changeover causes them to be sent
1356  * over another link with an additional tunnel header added as prefix.
1357  * (Refragmentation will still occur if the other link has a smaller MTU.)
1358  *
1359  * Returns user data length or errno.
1360  */
1361 static int link_send_sections_long(struct port *sender,
1362                                    struct iovec const *msg_sect,
1363                                    u32 num_sect,
1364                                    u32 destaddr)
1365 {
1366         struct link *l_ptr;
1367         struct tipc_node *node;
1368         struct tipc_msg *hdr = &sender->publ.phdr;
1369         u32 dsz = msg_data_sz(hdr);
1370         u32 max_pkt,fragm_sz,rest;
1371         struct tipc_msg fragm_hdr;
1372         struct sk_buff *buf,*buf_chain,*prev;
1373         u32 fragm_crs,fragm_rest,hsz,sect_rest;
1374         const unchar *sect_crs;
1375         int curr_sect;
1376         u32 fragm_no;
1377
1378 again:
1379         fragm_no = 1;
1380         max_pkt = sender->publ.max_pkt - INT_H_SIZE;
1381                 /* leave room for tunnel header in case of link changeover */
1382         fragm_sz = max_pkt - INT_H_SIZE;
1383                 /* leave room for fragmentation header in each fragment */
1384         rest = dsz;
1385         fragm_crs = 0;
1386         fragm_rest = 0;
1387         sect_rest = 0;
1388         sect_crs = NULL;
1389         curr_sect = -1;
1390
1391         /* Prepare reusable fragment header: */
1392
1393         msg_dbg(hdr, ">FRAGMENTING>");
1394         msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
1395                  INT_H_SIZE, msg_destnode(hdr));
1396         msg_set_link_selector(&fragm_hdr, sender->publ.ref);
1397         msg_set_size(&fragm_hdr, max_pkt);
1398         msg_set_fragm_no(&fragm_hdr, 1);
1399
1400         /* Prepare header of first fragment: */
1401
1402         buf_chain = buf = buf_acquire(max_pkt);
1403         if (!buf)
1404                 return -ENOMEM;
1405         buf->next = NULL;
1406         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1407         hsz = msg_hdr_sz(hdr);
1408         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, hdr, hsz);
1409         msg_dbg(buf_msg(buf), ">BUILD>");
1410
1411         /* Chop up message: */
1412
1413         fragm_crs = INT_H_SIZE + hsz;
1414         fragm_rest = fragm_sz - hsz;
1415
1416         do {            /* For all sections */
1417                 u32 sz;
1418
1419                 if (!sect_rest) {
1420                         sect_rest = msg_sect[++curr_sect].iov_len;
1421                         sect_crs = (const unchar *)msg_sect[curr_sect].iov_base;
1422                 }
1423
1424                 if (sect_rest < fragm_rest)
1425                         sz = sect_rest;
1426                 else
1427                         sz = fragm_rest;
1428
1429                 if (likely(!sender->user_port)) {
1430                         if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
1431 error:
1432                                 for (; buf_chain; buf_chain = buf) {
1433                                         buf = buf_chain->next;
1434                                         buf_discard(buf_chain);
1435                                 }
1436                                 return -EFAULT;
1437                         }
1438                 } else
1439                         skb_copy_to_linear_data_offset(buf, fragm_crs,
1440                                                        sect_crs, sz);
1441                 sect_crs += sz;
1442                 sect_rest -= sz;
1443                 fragm_crs += sz;
1444                 fragm_rest -= sz;
1445                 rest -= sz;
1446
1447                 if (!fragm_rest && rest) {
1448
1449                         /* Initiate new fragment: */
1450                         if (rest <= fragm_sz) {
1451                                 fragm_sz = rest;
1452                                 msg_set_type(&fragm_hdr,LAST_FRAGMENT);
1453                         } else {
1454                                 msg_set_type(&fragm_hdr, FRAGMENT);
1455                         }
1456                         msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
1457                         msg_set_fragm_no(&fragm_hdr, ++fragm_no);
1458                         prev = buf;
1459                         buf = buf_acquire(fragm_sz + INT_H_SIZE);
1460                         if (!buf)
1461                                 goto error;
1462
1463                         buf->next = NULL;
1464                         prev->next = buf;
1465                         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1466                         fragm_crs = INT_H_SIZE;
1467                         fragm_rest = fragm_sz;
1468                         msg_dbg(buf_msg(buf),"  >BUILD>");
1469                 }
1470         }
1471         while (rest > 0);
1472
1473         /*
1474          * Now we have a buffer chain. Select a link and check
1475          * that packet size is still OK
1476          */
1477         node = tipc_node_select(destaddr, sender->publ.ref & 1);
1478         if (likely(node)) {
1479                 tipc_node_lock(node);
1480                 l_ptr = node->active_links[sender->publ.ref & 1];
1481                 if (!l_ptr) {
1482                         tipc_node_unlock(node);
1483                         goto reject;
1484                 }
1485                 if (link_max_pkt(l_ptr) < max_pkt) {
1486                         sender->publ.max_pkt = link_max_pkt(l_ptr);
1487                         tipc_node_unlock(node);
1488                         for (; buf_chain; buf_chain = buf) {
1489                                 buf = buf_chain->next;
1490                                 buf_discard(buf_chain);
1491                         }
1492                         goto again;
1493                 }
1494         } else {
1495 reject:
1496                 for (; buf_chain; buf_chain = buf) {
1497                         buf = buf_chain->next;
1498                         buf_discard(buf_chain);
1499                 }
1500                 return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1501                                                  TIPC_ERR_NO_NODE);
1502         }
1503
1504         /* Append whole chain to send queue: */
1505
1506         buf = buf_chain;
1507         l_ptr->long_msg_seq_no = mod(l_ptr->long_msg_seq_no + 1);
1508         if (!l_ptr->next_out)
1509                 l_ptr->next_out = buf_chain;
1510         l_ptr->stats.sent_fragmented++;
1511         while (buf) {
1512                 struct sk_buff *next = buf->next;
1513                 struct tipc_msg *msg = buf_msg(buf);
1514
1515                 l_ptr->stats.sent_fragments++;
1516                 msg_set_long_msgno(msg, l_ptr->long_msg_seq_no);
1517                 link_add_to_outqueue(l_ptr, buf, msg);
1518                 msg_dbg(msg, ">ADD>");
1519                 buf = next;
1520         }
1521
1522         /* Send it, if possible: */
1523
1524         tipc_link_push_queue(l_ptr);
1525         tipc_node_unlock(node);
1526         return dsz;
1527 }
1528
1529 /*
1530  * tipc_link_push_packet: Push one unsent packet to the media
1531  */
1532 u32 tipc_link_push_packet(struct link *l_ptr)
1533 {
1534         struct sk_buff *buf = l_ptr->first_out;
1535         u32 r_q_size = l_ptr->retransm_queue_size;
1536         u32 r_q_head = l_ptr->retransm_queue_head;
1537
1538         /* Step to position where retransmission failed, if any,    */
1539         /* consider that buffers may have been released in meantime */
1540
1541         if (r_q_size && buf) {
1542                 u32 last = lesser(mod(r_q_head + r_q_size),
1543                                   link_last_sent(l_ptr));
1544                 u32 first = msg_seqno(buf_msg(buf));
1545
1546                 while (buf && less(first, r_q_head)) {
1547                         first = mod(first + 1);
1548                         buf = buf->next;
1549                 }
1550                 l_ptr->retransm_queue_head = r_q_head = first;
1551                 l_ptr->retransm_queue_size = r_q_size = mod(last - first);
1552         }
1553
1554         /* Continue retransmission now, if there is anything: */
1555
1556         if (r_q_size && buf && !skb_cloned(buf)) {
1557                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1558                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1559                 if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1560                         msg_dbg(buf_msg(buf), ">DEF-RETR>");
1561                         l_ptr->retransm_queue_head = mod(++r_q_head);
1562                         l_ptr->retransm_queue_size = --r_q_size;
1563                         l_ptr->stats.retransmitted++;
1564                         return 0;
1565                 } else {
1566                         l_ptr->stats.bearer_congs++;
1567                         msg_dbg(buf_msg(buf), "|>DEF-RETR>");
1568                         return PUSH_FAILED;
1569                 }
1570         }
1571
1572         /* Send deferred protocol message, if any: */
1573
1574         buf = l_ptr->proto_msg_queue;
1575         if (buf) {
1576                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1577                 msg_set_bcast_ack(buf_msg(buf),l_ptr->owner->bclink.last_in);
1578                 if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1579                         msg_dbg(buf_msg(buf), ">DEF-PROT>");
1580                         l_ptr->unacked_window = 0;
1581                         buf_discard(buf);
1582                         l_ptr->proto_msg_queue = NULL;
1583                         return 0;
1584                 } else {
1585                         msg_dbg(buf_msg(buf), "|>DEF-PROT>");
1586                         l_ptr->stats.bearer_congs++;
1587                         return PUSH_FAILED;
1588                 }
1589         }
1590
1591         /* Send one deferred data message, if send window not full: */
1592
1593         buf = l_ptr->next_out;
1594         if (buf) {
1595                 struct tipc_msg *msg = buf_msg(buf);
1596                 u32 next = msg_seqno(msg);
1597                 u32 first = msg_seqno(buf_msg(l_ptr->first_out));
1598
1599                 if (mod(next - first) < l_ptr->queue_limit[0]) {
1600                         msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1601                         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1602                         if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1603                                 if (msg_user(msg) == MSG_BUNDLER)
1604                                         msg_set_type(msg, CLOSED_MSG);
1605                                 msg_dbg(msg, ">PUSH-DATA>");
1606                                 l_ptr->next_out = buf->next;
1607                                 return 0;
1608                         } else {
1609                                 msg_dbg(msg, "|PUSH-DATA|");
1610                                 l_ptr->stats.bearer_congs++;
1611                                 return PUSH_FAILED;
1612                         }
1613                 }
1614         }
1615         return PUSH_FINISHED;
1616 }
1617
1618 /*
1619  * push_queue(): push out the unsent messages of a link where
1620  *               congestion has abated. Node is locked
1621  */
1622 void tipc_link_push_queue(struct link *l_ptr)
1623 {
1624         u32 res;
1625
1626         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr))
1627                 return;
1628
1629         do {
1630                 res = tipc_link_push_packet(l_ptr);
1631         } while (!res);
1632
1633         if (res == PUSH_FAILED)
1634                 tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1635 }
1636
1637 static void link_reset_all(unsigned long addr)
1638 {
1639         struct tipc_node *n_ptr;
1640         char addr_string[16];
1641         u32 i;
1642
1643         read_lock_bh(&tipc_net_lock);
1644         n_ptr = tipc_node_find((u32)addr);
1645         if (!n_ptr) {
1646                 read_unlock_bh(&tipc_net_lock);
1647                 return; /* node no longer exists */
1648         }
1649
1650         tipc_node_lock(n_ptr);
1651
1652         warn("Resetting all links to %s\n",
1653              addr_string_fill(addr_string, n_ptr->addr));
1654
1655         for (i = 0; i < MAX_BEARERS; i++) {
1656                 if (n_ptr->links[i]) {
1657                         link_print(n_ptr->links[i], TIPC_OUTPUT,
1658                                    "Resetting link\n");
1659                         tipc_link_reset(n_ptr->links[i]);
1660                 }
1661         }
1662
1663         tipc_node_unlock(n_ptr);
1664         read_unlock_bh(&tipc_net_lock);
1665 }
1666
1667 static void link_retransmit_failure(struct link *l_ptr, struct sk_buff *buf)
1668 {
1669         struct tipc_msg *msg = buf_msg(buf);
1670
1671         warn("Retransmission failure on link <%s>\n", l_ptr->name);
1672         tipc_msg_dbg(TIPC_OUTPUT, msg, ">RETR-FAIL>");
1673
1674         if (l_ptr->addr) {
1675
1676                 /* Handle failure on standard link */
1677
1678                 link_print(l_ptr, TIPC_OUTPUT, "Resetting link\n");
1679                 tipc_link_reset(l_ptr);
1680
1681         } else {
1682
1683                 /* Handle failure on broadcast link */
1684
1685                 struct tipc_node *n_ptr;
1686                 char addr_string[16];
1687
1688                 tipc_printf(TIPC_OUTPUT, "Msg seq number: %u,  ", msg_seqno(msg));
1689                 tipc_printf(TIPC_OUTPUT, "Outstanding acks: %lu\n",
1690                                      (unsigned long) TIPC_SKB_CB(buf)->handle);
1691
1692                 n_ptr = l_ptr->owner->next;
1693                 tipc_node_lock(n_ptr);
1694
1695                 addr_string_fill(addr_string, n_ptr->addr);
1696                 tipc_printf(TIPC_OUTPUT, "Multicast link info for %s\n", addr_string);
1697                 tipc_printf(TIPC_OUTPUT, "Supported: %d,  ", n_ptr->bclink.supported);
1698                 tipc_printf(TIPC_OUTPUT, "Acked: %u\n", n_ptr->bclink.acked);
1699                 tipc_printf(TIPC_OUTPUT, "Last in: %u,  ", n_ptr->bclink.last_in);
1700                 tipc_printf(TIPC_OUTPUT, "Gap after: %u,  ", n_ptr->bclink.gap_after);
1701                 tipc_printf(TIPC_OUTPUT, "Gap to: %u\n", n_ptr->bclink.gap_to);
1702                 tipc_printf(TIPC_OUTPUT, "Nack sync: %u\n\n", n_ptr->bclink.nack_sync);
1703
1704                 tipc_k_signal((Handler)link_reset_all, (unsigned long)n_ptr->addr);
1705
1706                 tipc_node_unlock(n_ptr);
1707
1708                 l_ptr->stale_count = 0;
1709         }
1710 }
1711
1712 void tipc_link_retransmit(struct link *l_ptr, struct sk_buff *buf,
1713                           u32 retransmits)
1714 {
1715         struct tipc_msg *msg;
1716
1717         if (!buf)
1718                 return;
1719
1720         msg = buf_msg(buf);
1721
1722         dbg("Retransmitting %u in link %x\n", retransmits, l_ptr);
1723
1724         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
1725                 if (!skb_cloned(buf)) {
1726                         msg_dbg(msg, ">NO_RETR->BCONG>");
1727                         dbg_print_link(l_ptr, "   ");
1728                         l_ptr->retransm_queue_head = msg_seqno(msg);
1729                         l_ptr->retransm_queue_size = retransmits;
1730                         return;
1731                 } else {
1732                         /* Don't retransmit if driver already has the buffer */
1733                 }
1734         } else {
1735                 /* Detect repeated retransmit failures on uncongested bearer */
1736
1737                 if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1738                         if (++l_ptr->stale_count > 100) {
1739                                 link_retransmit_failure(l_ptr, buf);
1740                                 return;
1741                         }
1742                 } else {
1743                         l_ptr->last_retransmitted = msg_seqno(msg);
1744                         l_ptr->stale_count = 1;
1745                 }
1746         }
1747
1748         while (retransmits && (buf != l_ptr->next_out) && buf && !skb_cloned(buf)) {
1749                 msg = buf_msg(buf);
1750                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1751                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1752                 if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1753                         msg_dbg(buf_msg(buf), ">RETR>");
1754                         buf = buf->next;
1755                         retransmits--;
1756                         l_ptr->stats.retransmitted++;
1757                 } else {
1758                         tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1759                         l_ptr->stats.bearer_congs++;
1760                         l_ptr->retransm_queue_head = msg_seqno(buf_msg(buf));
1761                         l_ptr->retransm_queue_size = retransmits;
1762                         return;
1763                 }
1764         }
1765
1766         l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
1767 }
1768
1769 /**
1770  * link_insert_deferred_queue - insert deferred messages back into receive chain
1771  */
1772
1773 static struct sk_buff *link_insert_deferred_queue(struct link *l_ptr,
1774                                                   struct sk_buff *buf)
1775 {
1776         u32 seq_no;
1777
1778         if (l_ptr->oldest_deferred_in == NULL)
1779                 return buf;
1780
1781         seq_no = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
1782         if (seq_no == mod(l_ptr->next_in_no)) {
1783                 l_ptr->newest_deferred_in->next = buf;
1784                 buf = l_ptr->oldest_deferred_in;
1785                 l_ptr->oldest_deferred_in = NULL;
1786                 l_ptr->deferred_inqueue_sz = 0;
1787         }
1788         return buf;
1789 }
1790
1791 /**
1792  * link_recv_buf_validate - validate basic format of received message
1793  *
1794  * This routine ensures a TIPC message has an acceptable header, and at least
1795  * as much data as the header indicates it should.  The routine also ensures
1796  * that the entire message header is stored in the main fragment of the message
1797  * buffer, to simplify future access to message header fields.
1798  *
1799  * Note: Having extra info present in the message header or data areas is OK.
1800  * TIPC will ignore the excess, under the assumption that it is optional info
1801  * introduced by a later release of the protocol.
1802  */
1803
1804 static int link_recv_buf_validate(struct sk_buff *buf)
1805 {
1806         static u32 min_data_hdr_size[8] = {
1807                 SHORT_H_SIZE, MCAST_H_SIZE, LONG_H_SIZE, DIR_MSG_H_SIZE,
1808                 MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE
1809                 };
1810
1811         struct tipc_msg *msg;
1812         u32 tipc_hdr[2];
1813         u32 size;
1814         u32 hdr_size;
1815         u32 min_hdr_size;
1816
1817         if (unlikely(buf->len < MIN_H_SIZE))
1818                 return 0;
1819
1820         msg = skb_header_pointer(buf, 0, sizeof(tipc_hdr), tipc_hdr);
1821         if (msg == NULL)
1822                 return 0;
1823
1824         if (unlikely(msg_version(msg) != TIPC_VERSION))
1825                 return 0;
1826
1827         size = msg_size(msg);
1828         hdr_size = msg_hdr_sz(msg);
1829         min_hdr_size = msg_isdata(msg) ?
1830                 min_data_hdr_size[msg_type(msg)] : INT_H_SIZE;
1831
1832         if (unlikely((hdr_size < min_hdr_size) ||
1833                      (size < hdr_size) ||
1834                      (buf->len < size) ||
1835                      (size - hdr_size > TIPC_MAX_USER_MSG_SIZE)))
1836                 return 0;
1837
1838         return pskb_may_pull(buf, hdr_size);
1839 }
1840
1841 void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *tb_ptr)
1842 {
1843         read_lock_bh(&tipc_net_lock);
1844         while (head) {
1845                 struct bearer *b_ptr = (struct bearer *)tb_ptr;
1846                 struct tipc_node *n_ptr;
1847                 struct link *l_ptr;
1848                 struct sk_buff *crs;
1849                 struct sk_buff *buf = head;
1850                 struct tipc_msg *msg;
1851                 u32 seq_no;
1852                 u32 ackd;
1853                 u32 released = 0;
1854                 int type;
1855
1856                 head = head->next;
1857
1858                 /* Ensure message is well-formed */
1859
1860                 if (unlikely(!link_recv_buf_validate(buf)))
1861                         goto cont;
1862
1863                 /* Ensure message data is a single contiguous unit */
1864
1865                 if (unlikely(buf_linearize(buf))) {
1866                         goto cont;
1867                 }
1868
1869                 /* Handle arrival of a non-unicast link message */
1870
1871                 msg = buf_msg(buf);
1872
1873                 if (unlikely(msg_non_seq(msg))) {
1874                         if (msg_user(msg) ==  LINK_CONFIG)
1875                                 tipc_disc_recv_msg(buf, b_ptr);
1876                         else
1877                                 tipc_bclink_recv_pkt(buf);
1878                         continue;
1879                 }
1880
1881                 if (unlikely(!msg_short(msg) &&
1882                              (msg_destnode(msg) != tipc_own_addr)))
1883                         goto cont;
1884
1885                 /* Discard non-routeable messages destined for another node */
1886
1887                 if (unlikely(!msg_isdata(msg) &&
1888                              (msg_destnode(msg) != tipc_own_addr))) {
1889                         if ((msg_user(msg) != CONN_MANAGER) &&
1890                             (msg_user(msg) != MSG_FRAGMENTER))
1891                                 goto cont;
1892                 }
1893
1894                 /* Locate unicast link endpoint that should handle message */
1895
1896                 n_ptr = tipc_node_find(msg_prevnode(msg));
1897                 if (unlikely(!n_ptr))
1898                         goto cont;
1899                 tipc_node_lock(n_ptr);
1900
1901                 l_ptr = n_ptr->links[b_ptr->identity];
1902                 if (unlikely(!l_ptr)) {
1903                         tipc_node_unlock(n_ptr);
1904                         goto cont;
1905                 }
1906
1907                 /* Validate message sequence number info */
1908
1909                 seq_no = msg_seqno(msg);
1910                 ackd = msg_ack(msg);
1911
1912                 /* Release acked messages */
1913
1914                 if (less(n_ptr->bclink.acked, msg_bcast_ack(msg))) {
1915                         if (tipc_node_is_up(n_ptr) && n_ptr->bclink.supported)
1916                                 tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1917                 }
1918
1919                 crs = l_ptr->first_out;
1920                 while ((crs != l_ptr->next_out) &&
1921                        less_eq(msg_seqno(buf_msg(crs)), ackd)) {
1922                         struct sk_buff *next = crs->next;
1923
1924                         buf_discard(crs);
1925                         crs = next;
1926                         released++;
1927                 }
1928                 if (released) {
1929                         l_ptr->first_out = crs;
1930                         l_ptr->out_queue_size -= released;
1931                 }
1932
1933                 /* Try sending any messages link endpoint has pending */
1934
1935                 if (unlikely(l_ptr->next_out))
1936                         tipc_link_push_queue(l_ptr);
1937                 if (unlikely(!list_empty(&l_ptr->waiting_ports)))
1938                         tipc_link_wakeup_ports(l_ptr, 0);
1939                 if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1940                         l_ptr->stats.sent_acks++;
1941                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1942                 }
1943
1944                 /* Now (finally!) process the incoming message */
1945
1946 protocol_check:
1947                 if (likely(link_working_working(l_ptr))) {
1948                         if (likely(seq_no == mod(l_ptr->next_in_no))) {
1949                                 l_ptr->next_in_no++;
1950                                 if (unlikely(l_ptr->oldest_deferred_in))
1951                                         head = link_insert_deferred_queue(l_ptr,
1952                                                                           head);
1953                                 if (likely(msg_is_dest(msg, tipc_own_addr))) {
1954 deliver:
1955                                         if (likely(msg_isdata(msg))) {
1956                                                 tipc_node_unlock(n_ptr);
1957                                                 tipc_port_recv_msg(buf);
1958                                                 continue;
1959                                         }
1960                                         switch (msg_user(msg)) {
1961                                         case MSG_BUNDLER:
1962                                                 l_ptr->stats.recv_bundles++;
1963                                                 l_ptr->stats.recv_bundled +=
1964                                                         msg_msgcnt(msg);
1965                                                 tipc_node_unlock(n_ptr);
1966                                                 tipc_link_recv_bundle(buf);
1967                                                 continue;
1968                                         case ROUTE_DISTRIBUTOR:
1969                                                 tipc_node_unlock(n_ptr);
1970                                                 tipc_cltr_recv_routing_table(buf);
1971                                                 continue;
1972                                         case NAME_DISTRIBUTOR:
1973                                                 tipc_node_unlock(n_ptr);
1974                                                 tipc_named_recv(buf);
1975                                                 continue;
1976                                         case CONN_MANAGER:
1977                                                 tipc_node_unlock(n_ptr);
1978                                                 tipc_port_recv_proto_msg(buf);
1979                                                 continue;
1980                                         case MSG_FRAGMENTER:
1981                                                 l_ptr->stats.recv_fragments++;
1982                                                 if (tipc_link_recv_fragment(&l_ptr->defragm_buf,
1983                                                                             &buf, &msg)) {
1984                                                         l_ptr->stats.recv_fragmented++;
1985                                                         goto deliver;
1986                                                 }
1987                                                 break;
1988                                         case CHANGEOVER_PROTOCOL:
1989                                                 type = msg_type(msg);
1990                                                 if (link_recv_changeover_msg(&l_ptr, &buf)) {
1991                                                         msg = buf_msg(buf);
1992                                                         seq_no = msg_seqno(msg);
1993                                                         if (type == ORIGINAL_MSG)
1994                                                                 goto deliver;
1995                                                         goto protocol_check;
1996                                                 }
1997                                                 break;
1998                                         }
1999                                 }
2000                                 tipc_node_unlock(n_ptr);
2001                                 tipc_net_route_msg(buf);
2002                                 continue;
2003                         }
2004                         link_handle_out_of_seq_msg(l_ptr, buf);
2005                         head = link_insert_deferred_queue(l_ptr, head);
2006                         tipc_node_unlock(n_ptr);
2007                         continue;
2008                 }
2009
2010                 if (msg_user(msg) == LINK_PROTOCOL) {
2011                         link_recv_proto_msg(l_ptr, buf);
2012                         head = link_insert_deferred_queue(l_ptr, head);
2013                         tipc_node_unlock(n_ptr);
2014                         continue;
2015                 }
2016                 msg_dbg(msg,"NSEQ<REC<");
2017                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
2018
2019                 if (link_working_working(l_ptr)) {
2020                         /* Re-insert in front of queue */
2021                         msg_dbg(msg,"RECV-REINS:");
2022                         buf->next = head;
2023                         head = buf;
2024                         tipc_node_unlock(n_ptr);
2025                         continue;
2026                 }
2027                 tipc_node_unlock(n_ptr);
2028 cont:
2029                 buf_discard(buf);
2030         }
2031         read_unlock_bh(&tipc_net_lock);
2032 }
2033
2034 /*
2035  * link_defer_buf(): Sort a received out-of-sequence packet
2036  *                   into the deferred reception queue.
2037  * Returns the increase of the queue length,i.e. 0 or 1
2038  */
2039
2040 u32 tipc_link_defer_pkt(struct sk_buff **head,
2041                         struct sk_buff **tail,
2042                         struct sk_buff *buf)
2043 {
2044         struct sk_buff *prev = NULL;
2045         struct sk_buff *crs = *head;
2046         u32 seq_no = msg_seqno(buf_msg(buf));
2047
2048         buf->next = NULL;
2049
2050         /* Empty queue ? */
2051         if (*head == NULL) {
2052                 *head = *tail = buf;
2053                 return 1;
2054         }
2055
2056         /* Last ? */
2057         if (less(msg_seqno(buf_msg(*tail)), seq_no)) {
2058                 (*tail)->next = buf;
2059                 *tail = buf;
2060                 return 1;
2061         }
2062
2063         /* Scan through queue and sort it in */
2064         do {
2065                 struct tipc_msg *msg = buf_msg(crs);
2066
2067                 if (less(seq_no, msg_seqno(msg))) {
2068                         buf->next = crs;
2069                         if (prev)
2070                                 prev->next = buf;
2071                         else
2072                                 *head = buf;
2073                         return 1;
2074                 }
2075                 if (seq_no == msg_seqno(msg)) {
2076                         break;
2077                 }
2078                 prev = crs;
2079                 crs = crs->next;
2080         }
2081         while (crs);
2082
2083         /* Message is a duplicate of an existing message */
2084
2085         buf_discard(buf);
2086         return 0;
2087 }
2088
2089 /**
2090  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
2091  */
2092
2093 static void link_handle_out_of_seq_msg(struct link *l_ptr,
2094                                        struct sk_buff *buf)
2095 {
2096         u32 seq_no = msg_seqno(buf_msg(buf));
2097
2098         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
2099                 link_recv_proto_msg(l_ptr, buf);
2100                 return;
2101         }
2102
2103         dbg("rx OOS msg: seq_no %u, expecting %u (%u)\n",
2104             seq_no, mod(l_ptr->next_in_no), l_ptr->next_in_no);
2105
2106         /* Record OOS packet arrival (force mismatch on next timeout) */
2107
2108         l_ptr->checkpoint--;
2109
2110         /*
2111          * Discard packet if a duplicate; otherwise add it to deferred queue
2112          * and notify peer of gap as per protocol specification
2113          */
2114
2115         if (less(seq_no, mod(l_ptr->next_in_no))) {
2116                 l_ptr->stats.duplicates++;
2117                 buf_discard(buf);
2118                 return;
2119         }
2120
2121         if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
2122                                 &l_ptr->newest_deferred_in, buf)) {
2123                 l_ptr->deferred_inqueue_sz++;
2124                 l_ptr->stats.deferred_recv++;
2125                 if ((l_ptr->deferred_inqueue_sz % 16) == 1)
2126                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
2127         } else
2128                 l_ptr->stats.duplicates++;
2129 }
2130
2131 /*
2132  * Send protocol message to the other endpoint.
2133  */
2134 void tipc_link_send_proto_msg(struct link *l_ptr, u32 msg_typ, int probe_msg,
2135                               u32 gap, u32 tolerance, u32 priority, u32 ack_mtu)
2136 {
2137         struct sk_buff *buf = NULL;
2138         struct tipc_msg *msg = l_ptr->pmsg;
2139         u32 msg_size = sizeof(l_ptr->proto_msg);
2140
2141         if (link_blocked(l_ptr))
2142                 return;
2143         msg_set_type(msg, msg_typ);
2144         msg_set_net_plane(msg, l_ptr->b_ptr->net_plane);
2145         msg_set_bcast_ack(msg, mod(l_ptr->owner->bclink.last_in));
2146         msg_set_last_bcast(msg, tipc_bclink_get_last_sent());
2147
2148         if (msg_typ == STATE_MSG) {
2149                 u32 next_sent = mod(l_ptr->next_out_no);
2150
2151                 if (!tipc_link_is_up(l_ptr))
2152                         return;
2153                 if (l_ptr->next_out)
2154                         next_sent = msg_seqno(buf_msg(l_ptr->next_out));
2155                 msg_set_next_sent(msg, next_sent);
2156                 if (l_ptr->oldest_deferred_in) {
2157                         u32 rec = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
2158                         gap = mod(rec - mod(l_ptr->next_in_no));
2159                 }
2160                 msg_set_seq_gap(msg, gap);
2161                 if (gap)
2162                         l_ptr->stats.sent_nacks++;
2163                 msg_set_link_tolerance(msg, tolerance);
2164                 msg_set_linkprio(msg, priority);
2165                 msg_set_max_pkt(msg, ack_mtu);
2166                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
2167                 msg_set_probe(msg, probe_msg != 0);
2168                 if (probe_msg) {
2169                         u32 mtu = l_ptr->max_pkt;
2170
2171                         if ((mtu < l_ptr->max_pkt_target) &&
2172                             link_working_working(l_ptr) &&
2173                             l_ptr->fsm_msg_cnt) {
2174                                 msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
2175                                 if (l_ptr->max_pkt_probes == 10) {
2176                                         l_ptr->max_pkt_target = (msg_size - 4);
2177                                         l_ptr->max_pkt_probes = 0;
2178                                         msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
2179                                 }
2180                                 l_ptr->max_pkt_probes++;
2181                         }
2182
2183                         l_ptr->stats.sent_probes++;
2184                 }
2185                 l_ptr->stats.sent_states++;
2186         } else {                /* RESET_MSG or ACTIVATE_MSG */
2187                 msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
2188                 msg_set_seq_gap(msg, 0);
2189                 msg_set_next_sent(msg, 1);
2190                 msg_set_link_tolerance(msg, l_ptr->tolerance);
2191                 msg_set_linkprio(msg, l_ptr->priority);
2192                 msg_set_max_pkt(msg, l_ptr->max_pkt_target);
2193         }
2194
2195         if (tipc_node_has_redundant_links(l_ptr->owner)) {
2196                 msg_set_redundant_link(msg);
2197         } else {
2198                 msg_clear_redundant_link(msg);
2199         }
2200         msg_set_linkprio(msg, l_ptr->priority);
2201
2202         /* Ensure sequence number will not fit : */
2203
2204         msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
2205
2206         /* Congestion? */
2207
2208         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
2209                 if (!l_ptr->proto_msg_queue) {
2210                         l_ptr->proto_msg_queue =
2211                                 buf_acquire(sizeof(l_ptr->proto_msg));
2212                 }
2213                 buf = l_ptr->proto_msg_queue;
2214                 if (!buf)
2215                         return;
2216                 skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
2217                 return;
2218         }
2219         msg_set_timestamp(msg, jiffies_to_msecs(jiffies));
2220
2221         /* Message can be sent */
2222
2223         msg_dbg(msg, ">>");
2224
2225         buf = buf_acquire(msg_size);
2226         if (!buf)
2227                 return;
2228
2229         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
2230         msg_set_size(buf_msg(buf), msg_size);
2231
2232         if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
2233                 l_ptr->unacked_window = 0;
2234                 buf_discard(buf);
2235                 return;
2236         }
2237
2238         /* New congestion */
2239         tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
2240         l_ptr->proto_msg_queue = buf;
2241         l_ptr->stats.bearer_congs++;
2242 }
2243
2244 /*
2245  * Receive protocol message :
2246  * Note that network plane id propagates through the network, and may
2247  * change at any time. The node with lowest address rules
2248  */
2249
2250 static void link_recv_proto_msg(struct link *l_ptr, struct sk_buff *buf)
2251 {
2252         u32 rec_gap = 0;
2253         u32 max_pkt_info;
2254         u32 max_pkt_ack;
2255         u32 msg_tol;
2256         struct tipc_msg *msg = buf_msg(buf);
2257
2258         dbg("AT(%u):", jiffies_to_msecs(jiffies));
2259         msg_dbg(msg, "<<");
2260         if (link_blocked(l_ptr))
2261                 goto exit;
2262
2263         /* record unnumbered packet arrival (force mismatch on next timeout) */
2264
2265         l_ptr->checkpoint--;
2266
2267         if (l_ptr->b_ptr->net_plane != msg_net_plane(msg))
2268                 if (tipc_own_addr > msg_prevnode(msg))
2269                         l_ptr->b_ptr->net_plane = msg_net_plane(msg);
2270
2271         l_ptr->owner->permit_changeover = msg_redundant_link(msg);
2272
2273         switch (msg_type(msg)) {
2274
2275         case RESET_MSG:
2276                 if (!link_working_unknown(l_ptr) &&
2277                     (l_ptr->peer_session != INVALID_SESSION)) {
2278                         if (msg_session(msg) == l_ptr->peer_session) {
2279                                 dbg("Duplicate RESET: %u<->%u\n",
2280                                     msg_session(msg), l_ptr->peer_session);
2281                                 break; /* duplicate: ignore */
2282                         }
2283                 }
2284                 /* fall thru' */
2285         case ACTIVATE_MSG:
2286                 /* Update link settings according other endpoint's values */
2287
2288                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
2289
2290                 if ((msg_tol = msg_link_tolerance(msg)) &&
2291                     (msg_tol > l_ptr->tolerance))
2292                         link_set_supervision_props(l_ptr, msg_tol);
2293
2294                 if (msg_linkprio(msg) > l_ptr->priority)
2295                         l_ptr->priority = msg_linkprio(msg);
2296
2297                 max_pkt_info = msg_max_pkt(msg);
2298                 if (max_pkt_info) {
2299                         if (max_pkt_info < l_ptr->max_pkt_target)
2300                                 l_ptr->max_pkt_target = max_pkt_info;
2301                         if (l_ptr->max_pkt > l_ptr->max_pkt_target)
2302                                 l_ptr->max_pkt = l_ptr->max_pkt_target;
2303                 } else {
2304                         l_ptr->max_pkt = l_ptr->max_pkt_target;
2305                 }
2306                 l_ptr->owner->bclink.supported = (max_pkt_info != 0);
2307
2308                 link_state_event(l_ptr, msg_type(msg));
2309
2310                 l_ptr->peer_session = msg_session(msg);
2311                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
2312
2313                 /* Synchronize broadcast sequence numbers */
2314                 if (!tipc_node_has_redundant_links(l_ptr->owner)) {
2315                         l_ptr->owner->bclink.last_in = mod(msg_last_bcast(msg));
2316                 }
2317                 break;
2318         case STATE_MSG:
2319
2320                 if ((msg_tol = msg_link_tolerance(msg)))
2321                         link_set_supervision_props(l_ptr, msg_tol);
2322
2323                 if (msg_linkprio(msg) &&
2324                     (msg_linkprio(msg) != l_ptr->priority)) {
2325                         warn("Resetting link <%s>, priority change %u->%u\n",
2326                              l_ptr->name, l_ptr->priority, msg_linkprio(msg));
2327                         l_ptr->priority = msg_linkprio(msg);
2328                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
2329                         break;
2330                 }
2331                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
2332                 l_ptr->stats.recv_states++;
2333                 if (link_reset_unknown(l_ptr))
2334                         break;
2335
2336                 if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
2337                         rec_gap = mod(msg_next_sent(msg) -
2338                                       mod(l_ptr->next_in_no));
2339                 }
2340
2341                 max_pkt_ack = msg_max_pkt(msg);
2342                 if (max_pkt_ack > l_ptr->max_pkt) {
2343                         dbg("Link <%s> updated MTU %u -> %u\n",
2344                             l_ptr->name, l_ptr->max_pkt, max_pkt_ack);
2345                         l_ptr->max_pkt = max_pkt_ack;
2346                         l_ptr->max_pkt_probes = 0;
2347                 }
2348
2349                 max_pkt_ack = 0;
2350                 if (msg_probe(msg)) {
2351                         l_ptr->stats.recv_probes++;
2352                         if (msg_size(msg) > sizeof(l_ptr->proto_msg)) {
2353                                 max_pkt_ack = msg_size(msg);
2354                         }
2355                 }
2356
2357                 /* Protocol message before retransmits, reduce loss risk */
2358
2359                 tipc_bclink_check_gap(l_ptr->owner, msg_last_bcast(msg));
2360
2361                 if (rec_gap || (msg_probe(msg))) {
2362                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2363                                                  0, rec_gap, 0, 0, max_pkt_ack);
2364                 }
2365                 if (msg_seq_gap(msg)) {
2366                         msg_dbg(msg, "With Gap:");
2367                         l_ptr->stats.recv_nacks++;
2368                         tipc_link_retransmit(l_ptr, l_ptr->first_out,
2369                                              msg_seq_gap(msg));
2370                 }
2371                 break;
2372         default:
2373                 msg_dbg(buf_msg(buf), "<DISCARDING UNKNOWN<");
2374         }
2375 exit:
2376         buf_discard(buf);
2377 }
2378
2379
2380 /*
2381  * tipc_link_tunnel(): Send one message via a link belonging to
2382  * another bearer. Owner node is locked.
2383  */
2384 void tipc_link_tunnel(struct link *l_ptr,
2385                       struct tipc_msg *tunnel_hdr,
2386                       struct tipc_msg  *msg,
2387                       u32 selector)
2388 {
2389         struct link *tunnel;
2390         struct sk_buff *buf;
2391         u32 length = msg_size(msg);
2392
2393         tunnel = l_ptr->owner->active_links[selector & 1];
2394         if (!tipc_link_is_up(tunnel)) {
2395                 warn("Link changeover error, "
2396                      "tunnel link no longer available\n");
2397                 return;
2398         }
2399         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
2400         buf = buf_acquire(length + INT_H_SIZE);
2401         if (!buf) {
2402                 warn("Link changeover error, "
2403                      "unable to send tunnel msg\n");
2404                 return;
2405         }
2406         skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
2407         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, msg, length);
2408         dbg("%c->%c:", l_ptr->b_ptr->net_plane, tunnel->b_ptr->net_plane);
2409         msg_dbg(buf_msg(buf), ">SEND>");
2410         tipc_link_send_buf(tunnel, buf);
2411 }
2412
2413
2414
2415 /*
2416  * changeover(): Send whole message queue via the remaining link
2417  *               Owner node is locked.
2418  */
2419
2420 void tipc_link_changeover(struct link *l_ptr)
2421 {
2422         u32 msgcount = l_ptr->out_queue_size;
2423         struct sk_buff *crs = l_ptr->first_out;
2424         struct link *tunnel = l_ptr->owner->active_links[0];
2425         struct tipc_msg tunnel_hdr;
2426         int split_bundles;
2427
2428         if (!tunnel)
2429                 return;
2430
2431         if (!l_ptr->owner->permit_changeover) {
2432                 warn("Link changeover error, "
2433                      "peer did not permit changeover\n");
2434                 return;
2435         }
2436
2437         msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2438                  ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
2439         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2440         msg_set_msgcnt(&tunnel_hdr, msgcount);
2441         dbg("Link changeover requires %u tunnel messages\n", msgcount);
2442
2443         if (!l_ptr->first_out) {
2444                 struct sk_buff *buf;
2445
2446                 buf = buf_acquire(INT_H_SIZE);
2447                 if (buf) {
2448                         skb_copy_to_linear_data(buf, &tunnel_hdr, INT_H_SIZE);
2449                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
2450                         dbg("%c->%c:", l_ptr->b_ptr->net_plane,
2451                             tunnel->b_ptr->net_plane);
2452                         msg_dbg(&tunnel_hdr, "EMPTY>SEND>");
2453                         tipc_link_send_buf(tunnel, buf);
2454                 } else {
2455                         warn("Link changeover error, "
2456                              "unable to send changeover msg\n");
2457                 }
2458                 return;
2459         }
2460
2461         split_bundles = (l_ptr->owner->active_links[0] !=
2462                          l_ptr->owner->active_links[1]);
2463
2464         while (crs) {
2465                 struct tipc_msg *msg = buf_msg(crs);
2466
2467                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
2468                         struct tipc_msg *m = msg_get_wrapped(msg);
2469                         unchar* pos = (unchar*)m;
2470
2471                         msgcount = msg_msgcnt(msg);
2472                         while (msgcount--) {
2473                                 msg_set_seqno(m,msg_seqno(msg));
2474                                 tipc_link_tunnel(l_ptr, &tunnel_hdr, m,
2475                                                  msg_link_selector(m));
2476                                 pos += align(msg_size(m));
2477                                 m = (struct tipc_msg *)pos;
2478                         }
2479                 } else {
2480                         tipc_link_tunnel(l_ptr, &tunnel_hdr, msg,
2481                                          msg_link_selector(msg));
2482                 }
2483                 crs = crs->next;
2484         }
2485 }
2486
2487 void tipc_link_send_duplicate(struct link *l_ptr, struct link *tunnel)
2488 {
2489         struct sk_buff *iter;
2490         struct tipc_msg tunnel_hdr;
2491
2492         msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2493                  DUPLICATE_MSG, INT_H_SIZE, l_ptr->addr);
2494         msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
2495         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2496         iter = l_ptr->first_out;
2497         while (iter) {
2498                 struct sk_buff *outbuf;
2499                 struct tipc_msg *msg = buf_msg(iter);
2500                 u32 length = msg_size(msg);
2501
2502                 if (msg_user(msg) == MSG_BUNDLER)
2503                         msg_set_type(msg, CLOSED_MSG);
2504                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));   /* Update */
2505                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
2506                 msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
2507                 outbuf = buf_acquire(length + INT_H_SIZE);
2508                 if (outbuf == NULL) {
2509                         warn("Link changeover error, "
2510                              "unable to send duplicate msg\n");
2511                         return;
2512                 }
2513                 skb_copy_to_linear_data(outbuf, &tunnel_hdr, INT_H_SIZE);
2514                 skb_copy_to_linear_data_offset(outbuf, INT_H_SIZE, iter->data,
2515                                                length);
2516                 dbg("%c->%c:", l_ptr->b_ptr->net_plane,
2517                     tunnel->b_ptr->net_plane);
2518                 msg_dbg(buf_msg(outbuf), ">SEND>");
2519                 tipc_link_send_buf(tunnel, outbuf);
2520                 if (!tipc_link_is_up(l_ptr))
2521                         return;
2522                 iter = iter->next;
2523         }
2524 }
2525
2526
2527
2528 /**
2529  * buf_extract - extracts embedded TIPC message from another message
2530  * @skb: encapsulating message buffer
2531  * @from_pos: offset to extract from
2532  *
2533  * Returns a new message buffer containing an embedded message.  The
2534  * encapsulating message itself is left unchanged.
2535  */
2536
2537 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
2538 {
2539         struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
2540         u32 size = msg_size(msg);
2541         struct sk_buff *eb;
2542
2543         eb = buf_acquire(size);
2544         if (eb)
2545                 skb_copy_to_linear_data(eb, msg, size);
2546         return eb;
2547 }
2548
2549 /*
2550  *  link_recv_changeover_msg(): Receive tunneled packet sent
2551  *  via other link. Node is locked. Return extracted buffer.
2552  */
2553
2554 static int link_recv_changeover_msg(struct link **l_ptr,
2555                                     struct sk_buff **buf)
2556 {
2557         struct sk_buff *tunnel_buf = *buf;
2558         struct link *dest_link;
2559         struct tipc_msg *msg;
2560         struct tipc_msg *tunnel_msg = buf_msg(tunnel_buf);
2561         u32 msg_typ = msg_type(tunnel_msg);
2562         u32 msg_count = msg_msgcnt(tunnel_msg);
2563
2564         dest_link = (*l_ptr)->owner->links[msg_bearer_id(tunnel_msg)];
2565         if (!dest_link) {
2566                 msg_dbg(tunnel_msg, "NOLINK/<REC<");
2567                 goto exit;
2568         }
2569         if (dest_link == *l_ptr) {
2570                 err("Unexpected changeover message on link <%s>\n",
2571                     (*l_ptr)->name);
2572                 goto exit;
2573         }
2574         dbg("%c<-%c:", dest_link->b_ptr->net_plane,
2575             (*l_ptr)->b_ptr->net_plane);
2576         *l_ptr = dest_link;
2577         msg = msg_get_wrapped(tunnel_msg);
2578
2579         if (msg_typ == DUPLICATE_MSG) {
2580                 if (less(msg_seqno(msg), mod(dest_link->next_in_no))) {
2581                         msg_dbg(tunnel_msg, "DROP/<REC<");
2582                         goto exit;
2583                 }
2584                 *buf = buf_extract(tunnel_buf,INT_H_SIZE);
2585                 if (*buf == NULL) {
2586                         warn("Link changeover error, duplicate msg dropped\n");
2587                         goto exit;
2588                 }
2589                 msg_dbg(tunnel_msg, "TNL<REC<");
2590                 buf_discard(tunnel_buf);
2591                 return 1;
2592         }
2593
2594         /* First original message ?: */
2595
2596         if (tipc_link_is_up(dest_link)) {
2597                 msg_dbg(tunnel_msg, "UP/FIRST/<REC<");
2598                 info("Resetting link <%s>, changeover initiated by peer\n",
2599                      dest_link->name);
2600                 tipc_link_reset(dest_link);
2601                 dest_link->exp_msg_count = msg_count;
2602                 dbg("Expecting %u tunnelled messages\n", msg_count);
2603                 if (!msg_count)
2604                         goto exit;
2605         } else if (dest_link->exp_msg_count == START_CHANGEOVER) {
2606                 msg_dbg(tunnel_msg, "BLK/FIRST/<REC<");
2607                 dest_link->exp_msg_count = msg_count;
2608                 dbg("Expecting %u tunnelled messages\n", msg_count);
2609                 if (!msg_count)
2610                         goto exit;
2611         }
2612
2613         /* Receive original message */
2614
2615         if (dest_link->exp_msg_count == 0) {
2616                 warn("Link switchover error, "
2617                      "got too many tunnelled messages\n");
2618                 msg_dbg(tunnel_msg, "OVERDUE/DROP/<REC<");
2619                 dbg_print_link(dest_link, "LINK:");
2620                 goto exit;
2621         }
2622         dest_link->exp_msg_count--;
2623         if (less(msg_seqno(msg), dest_link->reset_checkpoint)) {
2624                 msg_dbg(tunnel_msg, "DROP/DUPL/<REC<");
2625                 goto exit;
2626         } else {
2627                 *buf = buf_extract(tunnel_buf, INT_H_SIZE);
2628                 if (*buf != NULL) {
2629                         msg_dbg(tunnel_msg, "TNL<REC<");
2630                         buf_discard(tunnel_buf);
2631                         return 1;
2632                 } else {
2633                         warn("Link changeover error, original msg dropped\n");
2634                 }
2635         }
2636 exit:
2637         *buf = NULL;
2638         buf_discard(tunnel_buf);
2639         return 0;
2640 }
2641
2642 /*
2643  *  Bundler functionality:
2644  */
2645 void tipc_link_recv_bundle(struct sk_buff *buf)
2646 {
2647         u32 msgcount = msg_msgcnt(buf_msg(buf));
2648         u32 pos = INT_H_SIZE;
2649         struct sk_buff *obuf;
2650
2651         msg_dbg(buf_msg(buf), "<BNDL<: ");
2652         while (msgcount--) {
2653                 obuf = buf_extract(buf, pos);
2654                 if (obuf == NULL) {
2655                         warn("Link unable to unbundle message(s)\n");
2656                         break;
2657                 }
2658                 pos += align(msg_size(buf_msg(obuf)));
2659                 msg_dbg(buf_msg(obuf), "     /");
2660                 tipc_net_route_msg(obuf);
2661         }
2662         buf_discard(buf);
2663 }
2664
2665 /*
2666  *  Fragmentation/defragmentation:
2667  */
2668
2669
2670 /*
2671  * tipc_link_send_long_buf: Entry for buffers needing fragmentation.
2672  * The buffer is complete, inclusive total message length.
2673  * Returns user data length.
2674  */
2675 int tipc_link_send_long_buf(struct link *l_ptr, struct sk_buff *buf)
2676 {
2677         struct tipc_msg *inmsg = buf_msg(buf);
2678         struct tipc_msg fragm_hdr;
2679         u32 insize = msg_size(inmsg);
2680         u32 dsz = msg_data_sz(inmsg);
2681         unchar *crs = buf->data;
2682         u32 rest = insize;
2683         u32 pack_sz = link_max_pkt(l_ptr);
2684         u32 fragm_sz = pack_sz - INT_H_SIZE;
2685         u32 fragm_no = 1;
2686         u32 destaddr;
2687
2688         if (msg_short(inmsg))
2689                 destaddr = l_ptr->addr;
2690         else
2691                 destaddr = msg_destnode(inmsg);
2692
2693         if (msg_routed(inmsg))
2694                 msg_set_prevnode(inmsg, tipc_own_addr);
2695
2696         /* Prepare reusable fragment header: */
2697
2698         msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
2699                  INT_H_SIZE, destaddr);
2700         msg_set_link_selector(&fragm_hdr, msg_link_selector(inmsg));
2701         msg_set_long_msgno(&fragm_hdr, mod(l_ptr->long_msg_seq_no++));
2702         msg_set_fragm_no(&fragm_hdr, fragm_no);
2703         l_ptr->stats.sent_fragmented++;
2704
2705         /* Chop up message: */
2706
2707         while (rest > 0) {
2708                 struct sk_buff *fragm;
2709
2710                 if (rest <= fragm_sz) {
2711                         fragm_sz = rest;
2712                         msg_set_type(&fragm_hdr, LAST_FRAGMENT);
2713                 }
2714                 fragm = buf_acquire(fragm_sz + INT_H_SIZE);
2715                 if (fragm == NULL) {
2716                         warn("Link unable to fragment message\n");
2717                         dsz = -ENOMEM;
2718                         goto exit;
2719                 }
2720                 msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
2721                 skb_copy_to_linear_data(fragm, &fragm_hdr, INT_H_SIZE);
2722                 skb_copy_to_linear_data_offset(fragm, INT_H_SIZE, crs,
2723                                                fragm_sz);
2724                 /*  Send queued messages first, if any: */
2725
2726                 l_ptr->stats.sent_fragments++;
2727                 tipc_link_send_buf(l_ptr, fragm);
2728                 if (!tipc_link_is_up(l_ptr))
2729                         return dsz;
2730                 msg_set_fragm_no(&fragm_hdr, ++fragm_no);
2731                 rest -= fragm_sz;
2732                 crs += fragm_sz;
2733                 msg_set_type(&fragm_hdr, FRAGMENT);
2734         }
2735 exit:
2736         buf_discard(buf);
2737         return dsz;
2738 }
2739
2740 /*
2741  * A pending message being re-assembled must store certain values
2742  * to handle subsequent fragments correctly. The following functions
2743  * help storing these values in unused, available fields in the
2744  * pending message. This makes dynamic memory allocation unecessary.
2745  */
2746
2747 static void set_long_msg_seqno(struct sk_buff *buf, u32 seqno)
2748 {
2749         msg_set_seqno(buf_msg(buf), seqno);
2750 }
2751
2752 static u32 get_fragm_size(struct sk_buff *buf)
2753 {
2754         return msg_ack(buf_msg(buf));
2755 }
2756
2757 static void set_fragm_size(struct sk_buff *buf, u32 sz)
2758 {
2759         msg_set_ack(buf_msg(buf), sz);
2760 }
2761
2762 static u32 get_expected_frags(struct sk_buff *buf)
2763 {
2764         return msg_bcast_ack(buf_msg(buf));
2765 }
2766
2767 static void set_expected_frags(struct sk_buff *buf, u32 exp)
2768 {
2769         msg_set_bcast_ack(buf_msg(buf), exp);
2770 }
2771
2772 static u32 get_timer_cnt(struct sk_buff *buf)
2773 {
2774         return msg_reroute_cnt(buf_msg(buf));
2775 }
2776
2777 static void incr_timer_cnt(struct sk_buff *buf)
2778 {
2779         msg_incr_reroute_cnt(buf_msg(buf));
2780 }
2781
2782 /*
2783  * tipc_link_recv_fragment(): Called with node lock on. Returns
2784  * the reassembled buffer if message is complete.
2785  */
2786 int tipc_link_recv_fragment(struct sk_buff **pending, struct sk_buff **fb,
2787                             struct tipc_msg **m)
2788 {
2789         struct sk_buff *prev = NULL;
2790         struct sk_buff *fbuf = *fb;
2791         struct tipc_msg *fragm = buf_msg(fbuf);
2792         struct sk_buff *pbuf = *pending;
2793         u32 long_msg_seq_no = msg_long_msgno(fragm);
2794
2795         *fb = NULL;
2796         msg_dbg(fragm,"FRG<REC<");
2797
2798         /* Is there an incomplete message waiting for this fragment? */
2799
2800         while (pbuf && ((msg_seqno(buf_msg(pbuf)) != long_msg_seq_no) ||
2801                         (msg_orignode(fragm) != msg_orignode(buf_msg(pbuf))))) {
2802                 prev = pbuf;
2803                 pbuf = pbuf->next;
2804         }
2805
2806         if (!pbuf && (msg_type(fragm) == FIRST_FRAGMENT)) {
2807                 struct tipc_msg *imsg = (struct tipc_msg *)msg_data(fragm);
2808                 u32 msg_sz = msg_size(imsg);
2809                 u32 fragm_sz = msg_data_sz(fragm);
2810                 u32 exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz);
2811                 u32 max =  TIPC_MAX_USER_MSG_SIZE + LONG_H_SIZE;
2812                 if (msg_type(imsg) == TIPC_MCAST_MSG)
2813                         max = TIPC_MAX_USER_MSG_SIZE + MCAST_H_SIZE;
2814                 if (msg_size(imsg) > max) {
2815                         msg_dbg(fragm,"<REC<Oversized: ");
2816                         buf_discard(fbuf);
2817                         return 0;
2818                 }
2819                 pbuf = buf_acquire(msg_size(imsg));
2820                 if (pbuf != NULL) {
2821                         pbuf->next = *pending;
2822                         *pending = pbuf;
2823                         skb_copy_to_linear_data(pbuf, imsg,
2824                                                 msg_data_sz(fragm));
2825                         /*  Prepare buffer for subsequent fragments. */
2826
2827                         set_long_msg_seqno(pbuf, long_msg_seq_no);
2828                         set_fragm_size(pbuf,fragm_sz);
2829                         set_expected_frags(pbuf,exp_fragm_cnt - 1);
2830                 } else {
2831                         warn("Link unable to reassemble fragmented message\n");
2832                 }
2833                 buf_discard(fbuf);
2834                 return 0;
2835         } else if (pbuf && (msg_type(fragm) != FIRST_FRAGMENT)) {
2836                 u32 dsz = msg_data_sz(fragm);
2837                 u32 fsz = get_fragm_size(pbuf);
2838                 u32 crs = ((msg_fragm_no(fragm) - 1) * fsz);
2839                 u32 exp_frags = get_expected_frags(pbuf) - 1;
2840                 skb_copy_to_linear_data_offset(pbuf, crs,
2841                                                msg_data(fragm), dsz);
2842                 buf_discard(fbuf);
2843
2844                 /* Is message complete? */
2845
2846                 if (exp_frags == 0) {
2847                         if (prev)
2848                                 prev->next = pbuf->next;
2849                         else
2850                                 *pending = pbuf->next;
2851                         msg_reset_reroute_cnt(buf_msg(pbuf));
2852                         *fb = pbuf;
2853                         *m = buf_msg(pbuf);
2854                         return 1;
2855                 }
2856                 set_expected_frags(pbuf,exp_frags);
2857                 return 0;
2858         }
2859         dbg(" Discarding orphan fragment %x\n",fbuf);
2860         msg_dbg(fragm,"ORPHAN:");
2861         dbg("Pending long buffers:\n");
2862         dbg_print_buf_chain(*pending);
2863         buf_discard(fbuf);
2864         return 0;
2865 }
2866
2867 /**
2868  * link_check_defragm_bufs - flush stale incoming message fragments
2869  * @l_ptr: pointer to link
2870  */
2871
2872 static void link_check_defragm_bufs(struct link *l_ptr)
2873 {
2874         struct sk_buff *prev = NULL;
2875         struct sk_buff *next = NULL;
2876         struct sk_buff *buf = l_ptr->defragm_buf;
2877
2878         if (!buf)
2879                 return;
2880         if (!link_working_working(l_ptr))
2881                 return;
2882         while (buf) {
2883                 u32 cnt = get_timer_cnt(buf);
2884
2885                 next = buf->next;
2886                 if (cnt < 4) {
2887                         incr_timer_cnt(buf);
2888                         prev = buf;
2889                 } else {
2890                         dbg(" Discarding incomplete long buffer\n");
2891                         msg_dbg(buf_msg(buf), "LONG:");
2892                         dbg_print_link(l_ptr, "curr:");
2893                         dbg("Pending long buffers:\n");
2894                         dbg_print_buf_chain(l_ptr->defragm_buf);
2895                         if (prev)
2896                                 prev->next = buf->next;
2897                         else
2898                                 l_ptr->defragm_buf = buf->next;
2899                         buf_discard(buf);
2900                 }
2901                 buf = next;
2902         }
2903 }
2904
2905
2906
2907 static void link_set_supervision_props(struct link *l_ptr, u32 tolerance)
2908 {
2909         l_ptr->tolerance = tolerance;
2910         l_ptr->continuity_interval =
2911                 ((tolerance / 4) > 500) ? 500 : tolerance / 4;
2912         l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
2913 }
2914
2915
2916 void tipc_link_set_queue_limits(struct link *l_ptr, u32 window)
2917 {
2918         /* Data messages from this node, inclusive FIRST_FRAGM */
2919         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE] = window;
2920         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE] = (window / 3) * 4;
2921         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE] = (window / 3) * 5;
2922         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE] = (window / 3) * 6;
2923         /* Transiting data messages,inclusive FIRST_FRAGM */
2924         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE + 4] = 300;
2925         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE + 4] = 600;
2926         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE + 4] = 900;
2927         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE + 4] = 1200;
2928         l_ptr->queue_limit[CONN_MANAGER] = 1200;
2929         l_ptr->queue_limit[ROUTE_DISTRIBUTOR] = 1200;
2930         l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
2931         l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
2932         /* FRAGMENT and LAST_FRAGMENT packets */
2933         l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
2934 }
2935
2936 /**
2937  * link_find_link - locate link by name
2938  * @name - ptr to link name string
2939  * @node - ptr to area to be filled with ptr to associated node
2940  *
2941  * Caller must hold 'tipc_net_lock' to ensure node and bearer are not deleted;
2942  * this also prevents link deletion.
2943  *
2944  * Returns pointer to link (or 0 if invalid link name).
2945  */
2946
2947 static struct link *link_find_link(const char *name, struct tipc_node **node)
2948 {
2949         struct link_name link_name_parts;
2950         struct bearer *b_ptr;
2951         struct link *l_ptr;
2952
2953         if (!link_name_validate(name, &link_name_parts))
2954                 return NULL;
2955
2956         b_ptr = tipc_bearer_find_interface(link_name_parts.if_local);
2957         if (!b_ptr)
2958                 return NULL;
2959
2960         *node = tipc_node_find(link_name_parts.addr_peer);
2961         if (!*node)
2962                 return NULL;
2963
2964         l_ptr = (*node)->links[b_ptr->identity];
2965         if (!l_ptr || strcmp(l_ptr->name, name))
2966                 return NULL;
2967
2968         return l_ptr;
2969 }
2970
2971 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2972                                      u16 cmd)
2973 {
2974         struct tipc_link_config *args;
2975         u32 new_value;
2976         struct link *l_ptr;
2977         struct tipc_node *node;
2978         int res;
2979
2980         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2981                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2982
2983         args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2984         new_value = ntohl(args->value);
2985
2986         if (!strcmp(args->name, tipc_bclink_name)) {
2987                 if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2988                     (tipc_bclink_set_queue_limits(new_value) == 0))
2989                         return tipc_cfg_reply_none();
2990                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2991                                                    " (cannot change setting on broadcast link)");
2992         }
2993
2994         read_lock_bh(&tipc_net_lock);
2995         l_ptr = link_find_link(args->name, &node);
2996         if (!l_ptr) {
2997                 read_unlock_bh(&tipc_net_lock);
2998                 return tipc_cfg_reply_error_string("link not found");
2999         }
3000
3001         tipc_node_lock(node);
3002         res = -EINVAL;
3003         switch (cmd) {
3004         case TIPC_CMD_SET_LINK_TOL:
3005                 if ((new_value >= TIPC_MIN_LINK_TOL) &&
3006                     (new_value <= TIPC_MAX_LINK_TOL)) {
3007                         link_set_supervision_props(l_ptr, new_value);
3008                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
3009                                                  0, 0, new_value, 0, 0);
3010                         res = 0;
3011                 }
3012                 break;
3013         case TIPC_CMD_SET_LINK_PRI:
3014                 if ((new_value >= TIPC_MIN_LINK_PRI) &&
3015                     (new_value <= TIPC_MAX_LINK_PRI)) {
3016                         l_ptr->priority = new_value;
3017                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
3018                                                  0, 0, 0, new_value, 0);
3019                         res = 0;
3020                 }
3021                 break;
3022         case TIPC_CMD_SET_LINK_WINDOW:
3023                 if ((new_value >= TIPC_MIN_LINK_WIN) &&
3024                     (new_value <= TIPC_MAX_LINK_WIN)) {
3025                         tipc_link_set_queue_limits(l_ptr, new_value);
3026                         res = 0;
3027                 }
3028                 break;
3029         }
3030         tipc_node_unlock(node);
3031
3032         read_unlock_bh(&tipc_net_lock);
3033         if (res)
3034                 return tipc_cfg_reply_error_string("cannot change link setting");
3035
3036         return tipc_cfg_reply_none();
3037 }
3038
3039 /**
3040  * link_reset_statistics - reset link statistics
3041  * @l_ptr: pointer to link
3042  */
3043
3044 static void link_reset_statistics(struct link *l_ptr)
3045 {
3046         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
3047         l_ptr->stats.sent_info = l_ptr->next_out_no;
3048         l_ptr->stats.recv_info = l_ptr->next_in_no;
3049 }
3050
3051 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
3052 {
3053         char *link_name;
3054         struct link *l_ptr;
3055         struct tipc_node *node;
3056
3057         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
3058                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
3059
3060         link_name = (char *)TLV_DATA(req_tlv_area);
3061         if (!strcmp(link_name, tipc_bclink_name)) {
3062                 if (tipc_bclink_reset_stats())
3063                         return tipc_cfg_reply_error_string("link not found");
3064                 return tipc_cfg_reply_none();
3065         }
3066
3067         read_lock_bh(&tipc_net_lock);
3068         l_ptr = link_find_link(link_name, &node);
3069         if (!l_ptr) {
3070                 read_unlock_bh(&tipc_net_lock);
3071                 return tipc_cfg_reply_error_string("link not found");
3072         }
3073
3074         tipc_node_lock(node);
3075         link_reset_statistics(l_ptr);
3076         tipc_node_unlock(node);
3077         read_unlock_bh(&tipc_net_lock);
3078         return tipc_cfg_reply_none();
3079 }
3080
3081 /**
3082  * percent - convert count to a percentage of total (rounding up or down)
3083  */
3084
3085 static u32 percent(u32 count, u32 total)
3086 {
3087         return (count * 100 + (total / 2)) / total;
3088 }
3089
3090 /**
3091  * tipc_link_stats - print link statistics
3092  * @name: link name
3093  * @buf: print buffer area
3094  * @buf_size: size of print buffer area
3095  *
3096  * Returns length of print buffer data string (or 0 if error)
3097  */
3098
3099 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
3100 {
3101         struct print_buf pb;
3102         struct link *l_ptr;
3103         struct tipc_node *node;
3104         char *status;
3105         u32 profile_total = 0;
3106
3107         if (!strcmp(name, tipc_bclink_name))
3108                 return tipc_bclink_stats(buf, buf_size);
3109
3110         tipc_printbuf_init(&pb, buf, buf_size);
3111
3112         read_lock_bh(&tipc_net_lock);
3113         l_ptr = link_find_link(name, &node);
3114         if (!l_ptr) {
3115                 read_unlock_bh(&tipc_net_lock);
3116                 return 0;
3117         }
3118         tipc_node_lock(node);
3119
3120         if (tipc_link_is_active(l_ptr))
3121                 status = "ACTIVE";
3122         else if (tipc_link_is_up(l_ptr))
3123                 status = "STANDBY";
3124         else
3125                 status = "DEFUNCT";
3126         tipc_printf(&pb, "Link <%s>\n"
3127                          "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
3128                          "  Window:%u packets\n",
3129                     l_ptr->name, status, link_max_pkt(l_ptr),
3130                     l_ptr->priority, l_ptr->tolerance, l_ptr->queue_limit[0]);
3131         tipc_printf(&pb, "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
3132                     l_ptr->next_in_no - l_ptr->stats.recv_info,
3133                     l_ptr->stats.recv_fragments,
3134                     l_ptr->stats.recv_fragmented,
3135                     l_ptr->stats.recv_bundles,
3136                     l_ptr->stats.recv_bundled);
3137         tipc_printf(&pb, "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
3138                     l_ptr->next_out_no - l_ptr->stats.sent_info,
3139                     l_ptr->stats.sent_fragments,
3140                     l_ptr->stats.sent_fragmented,
3141                     l_ptr->stats.sent_bundles,
3142                     l_ptr->stats.sent_bundled);
3143         profile_total = l_ptr->stats.msg_length_counts;
3144         if (!profile_total)
3145                 profile_total = 1;
3146         tipc_printf(&pb, "  TX profile sample:%u packets  average:%u octets\n"
3147                          "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
3148                          "-16354:%u%% -32768:%u%% -66000:%u%%\n",
3149                     l_ptr->stats.msg_length_counts,
3150                     l_ptr->stats.msg_lengths_total / profile_total,
3151                     percent(l_ptr->stats.msg_length_profile[0], profile_total),
3152                     percent(l_ptr->stats.msg_length_profile[1], profile_total),
3153                     percent(l_ptr->stats.msg_length_profile[2], profile_total),
3154                     percent(l_ptr->stats.msg_length_profile[3], profile_total),
3155                     percent(l_ptr->stats.msg_length_profile[4], profile_total),
3156                     percent(l_ptr->stats.msg_length_profile[5], profile_total),
3157                     percent(l_ptr->stats.msg_length_profile[6], profile_total));
3158         tipc_printf(&pb, "  RX states:%u probes:%u naks:%u defs:%u dups:%u\n",
3159                     l_ptr->stats.recv_states,
3160                     l_ptr->stats.recv_probes,
3161                     l_ptr->stats.recv_nacks,
3162                     l_ptr->stats.deferred_recv,
3163                     l_ptr->stats.duplicates);
3164         tipc_printf(&pb, "  TX states:%u probes:%u naks:%u acks:%u dups:%u\n",
3165                     l_ptr->stats.sent_states,
3166                     l_ptr->stats.sent_probes,
3167                     l_ptr->stats.sent_nacks,
3168                     l_ptr->stats.sent_acks,
3169                     l_ptr->stats.retransmitted);
3170         tipc_printf(&pb, "  Congestion bearer:%u link:%u  Send queue max:%u avg:%u\n",
3171                     l_ptr->stats.bearer_congs,
3172                     l_ptr->stats.link_congs,
3173                     l_ptr->stats.max_queue_sz,
3174                     l_ptr->stats.queue_sz_counts
3175                     ? (l_ptr->stats.accu_queue_sz / l_ptr->stats.queue_sz_counts)
3176                     : 0);
3177
3178         tipc_node_unlock(node);
3179         read_unlock_bh(&tipc_net_lock);
3180         return tipc_printbuf_validate(&pb);
3181 }
3182
3183 #define MAX_LINK_STATS_INFO 2000
3184
3185 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
3186 {
3187         struct sk_buff *buf;
3188         struct tlv_desc *rep_tlv;
3189         int str_len;
3190
3191         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
3192                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
3193
3194         buf = tipc_cfg_reply_alloc(TLV_SPACE(MAX_LINK_STATS_INFO));
3195         if (!buf)
3196                 return NULL;
3197
3198         rep_tlv = (struct tlv_desc *)buf->data;
3199
3200         str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
3201                                   (char *)TLV_DATA(rep_tlv), MAX_LINK_STATS_INFO);
3202         if (!str_len) {
3203                 buf_discard(buf);
3204                 return tipc_cfg_reply_error_string("link not found");
3205         }
3206
3207         skb_put(buf, TLV_SPACE(str_len));
3208         TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
3209
3210         return buf;
3211 }
3212
3213 #if 0
3214 int link_control(const char *name, u32 op, u32 val)
3215 {
3216         int res = -EINVAL;
3217         struct link *l_ptr;
3218         u32 bearer_id;
3219         struct tipc_node * node;
3220         u32 a;
3221
3222         a = link_name2addr(name, &bearer_id);
3223         read_lock_bh(&tipc_net_lock);
3224         node = tipc_node_find(a);
3225         if (node) {
3226                 tipc_node_lock(node);
3227                 l_ptr = node->links[bearer_id];
3228                 if (l_ptr) {
3229                         if (op == TIPC_REMOVE_LINK) {
3230                                 struct bearer *b_ptr = l_ptr->b_ptr;
3231                                 spin_lock_bh(&b_ptr->publ.lock);
3232                                 tipc_link_delete(l_ptr);
3233                                 spin_unlock_bh(&b_ptr->publ.lock);
3234                         }
3235                         if (op == TIPC_CMD_BLOCK_LINK) {
3236                                 tipc_link_reset(l_ptr);
3237                                 l_ptr->blocked = 1;
3238                         }
3239                         if (op == TIPC_CMD_UNBLOCK_LINK) {
3240                                 l_ptr->blocked = 0;
3241                         }
3242                         res = 0;
3243                 }
3244                 tipc_node_unlock(node);
3245         }
3246         read_unlock_bh(&tipc_net_lock);
3247         return res;
3248 }
3249 #endif
3250
3251 /**
3252  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
3253  * @dest: network address of destination node
3254  * @selector: used to select from set of active links
3255  *
3256  * If no active link can be found, uses default maximum packet size.
3257  */
3258
3259 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
3260 {
3261         struct tipc_node *n_ptr;
3262         struct link *l_ptr;
3263         u32 res = MAX_PKT_DEFAULT;
3264
3265         if (dest == tipc_own_addr)
3266                 return MAX_MSG_SIZE;
3267
3268         read_lock_bh(&tipc_net_lock);
3269         n_ptr = tipc_node_select(dest, selector);
3270         if (n_ptr) {
3271                 tipc_node_lock(n_ptr);
3272                 l_ptr = n_ptr->active_links[selector & 1];
3273                 if (l_ptr)
3274                         res = link_max_pkt(l_ptr);
3275                 tipc_node_unlock(n_ptr);
3276         }
3277         read_unlock_bh(&tipc_net_lock);
3278         return res;
3279 }
3280
3281 #if 0
3282 static void link_dump_rec_queue(struct link *l_ptr)
3283 {
3284         struct sk_buff *crs;
3285
3286         if (!l_ptr->oldest_deferred_in) {
3287                 info("Reception queue empty\n");
3288                 return;
3289         }
3290         info("Contents of Reception queue:\n");
3291         crs = l_ptr->oldest_deferred_in;
3292         while (crs) {
3293                 if (crs->data == (void *)0x0000a3a3) {
3294                         info("buffer %x invalid\n", crs);
3295                         return;
3296                 }
3297                 msg_dbg(buf_msg(crs), "In rec queue: \n");
3298                 crs = crs->next;
3299         }
3300 }
3301 #endif
3302
3303 static void link_dump_send_queue(struct link *l_ptr)
3304 {
3305         if (l_ptr->next_out) {
3306                 info("\nContents of unsent queue:\n");
3307                 dbg_print_buf_chain(l_ptr->next_out);
3308         }
3309         info("\nContents of send queue:\n");
3310         if (l_ptr->first_out) {
3311                 dbg_print_buf_chain(l_ptr->first_out);
3312         }
3313         info("Empty send queue\n");
3314 }
3315
3316 static void link_print(struct link *l_ptr, struct print_buf *buf,
3317                        const char *str)
3318 {
3319         tipc_printf(buf, str);
3320         if (link_reset_reset(l_ptr) || link_reset_unknown(l_ptr))
3321                 return;
3322         tipc_printf(buf, "Link %x<%s>:",
3323                     l_ptr->addr, l_ptr->b_ptr->publ.name);
3324         tipc_printf(buf, ": NXO(%u):", mod(l_ptr->next_out_no));
3325         tipc_printf(buf, "NXI(%u):", mod(l_ptr->next_in_no));
3326         tipc_printf(buf, "SQUE");
3327         if (l_ptr->first_out) {
3328                 tipc_printf(buf, "[%u..", msg_seqno(buf_msg(l_ptr->first_out)));
3329                 if (l_ptr->next_out)
3330                         tipc_printf(buf, "%u..",
3331                                     msg_seqno(buf_msg(l_ptr->next_out)));
3332                 tipc_printf(buf, "%u]",
3333                             msg_seqno(buf_msg
3334                                       (l_ptr->last_out)), l_ptr->out_queue_size);
3335                 if ((mod(msg_seqno(buf_msg(l_ptr->last_out)) -
3336                          msg_seqno(buf_msg(l_ptr->first_out)))
3337                      != (l_ptr->out_queue_size - 1)) ||
3338                     (l_ptr->last_out->next != NULL)) {
3339                         tipc_printf(buf, "\nSend queue inconsistency\n");
3340                         tipc_printf(buf, "first_out= %x ", l_ptr->first_out);
3341                         tipc_printf(buf, "next_out= %x ", l_ptr->next_out);
3342                         tipc_printf(buf, "last_out= %x ", l_ptr->last_out);
3343                         link_dump_send_queue(l_ptr);
3344                 }
3345         } else
3346                 tipc_printf(buf, "[]");
3347         tipc_printf(buf, "SQSIZ(%u)", l_ptr->out_queue_size);
3348         if (l_ptr->oldest_deferred_in) {
3349                 u32 o = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
3350                 u32 n = msg_seqno(buf_msg(l_ptr->newest_deferred_in));
3351                 tipc_printf(buf, ":RQUE[%u..%u]", o, n);
3352                 if (l_ptr->deferred_inqueue_sz != mod((n + 1) - o)) {
3353                         tipc_printf(buf, ":RQSIZ(%u)",
3354                                     l_ptr->deferred_inqueue_sz);
3355                 }
3356         }
3357         if (link_working_unknown(l_ptr))
3358                 tipc_printf(buf, ":WU");
3359         if (link_reset_reset(l_ptr))
3360                 tipc_printf(buf, ":RR");
3361         if (link_reset_unknown(l_ptr))
3362                 tipc_printf(buf, ":RU");
3363         if (link_working_working(l_ptr))
3364                 tipc_printf(buf, ":WW");
3365         tipc_printf(buf, "\n");
3366 }
3367