net/tipc/msg.c

   1 /*
   2  * net/tipc/msg.c: TIPC message header routines
   3  *
   4  * Copyright (c) 2000-2006, 2014-2015, Ericsson AB
   5  * Copyright (c) 2005, 2010-2011, 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 <net/sock.h>
  38 #include "core.h"
  39 #include "msg.h"
  40 #include "addr.h"
  41 #include "name_table.h"
  42
  43 #define MAX_FORWARD_SIZE 1024
  44
  45 static unsigned int align(unsigned int i)
  46 {
  47         return (i + 3) & ~3u;
  48 }
  49
  50 /**
  51  * tipc_buf_acquire - creates a TIPC message buffer
  52  * @size: message size (including TIPC header)
  53  *
  54  * Returns a new buffer with data pointers set to the specified size.
  55  *
  56  * NOTE: Headroom is reserved to allow prepending of a data link header.
  57  *       There may also be unrequested tailroom present at the buffer's end.
  58  */
  59 struct sk_buff *tipc_buf_acquire(u32 size)
  60 {
  61         struct sk_buff *skb;
  62         unsigned int buf_size = (BUF_HEADROOM + size + 3) & ~3u;
  63
  64         skb = alloc_skb_fclone(buf_size, GFP_ATOMIC);
  65         if (skb) {
  66                 skb_reserve(skb, BUF_HEADROOM);
  67                 skb_put(skb, size);
  68                 skb->next = NULL;
  69         }
  70         return skb;
  71 }
  72
  73 void tipc_msg_init(u32 own_node, struct tipc_msg *m, u32 user, u32 type,
  74                    u32 hsize, u32 dnode)
  75 {
  76         memset(m, 0, hsize);
  77         msg_set_version(m);
  78         msg_set_user(m, user);
  79         msg_set_hdr_sz(m, hsize);
  80         msg_set_size(m, hsize);
  81         msg_set_prevnode(m, own_node);
  82         msg_set_type(m, type);
  83         if (hsize > SHORT_H_SIZE) {
  84                 msg_set_orignode(m, own_node);
  85                 msg_set_destnode(m, dnode);
  86         }
  87 }
  88
  89 struct sk_buff *tipc_msg_create(uint user, uint type,
  90                                 uint hdr_sz, uint data_sz, u32 dnode,
  91                                 u32 onode, u32 dport, u32 oport, int errcode)
  92 {
  93         struct tipc_msg *msg;
  94         struct sk_buff *buf;
  95
  96         buf = tipc_buf_acquire(hdr_sz + data_sz);
  97         if (unlikely(!buf))
  98                 return NULL;
  99
 100         msg = buf_msg(buf);
 101         tipc_msg_init(onode, msg, user, type, hdr_sz, dnode);
 102         msg_set_size(msg, hdr_sz + data_sz);
 103         msg_set_origport(msg, oport);
 104         msg_set_destport(msg, dport);
 105         msg_set_errcode(msg, errcode);
 106         if (hdr_sz > SHORT_H_SIZE) {
 107                 msg_set_orignode(msg, onode);
 108                 msg_set_destnode(msg, dnode);
 109         }
 110         return buf;
 111 }
 112
 113 /* tipc_buf_append(): Append a buffer to the fragment list of another buffer
 114  * @*headbuf: in:  NULL for first frag, otherwise value returned from prev call
 115  *            out: set when successful non-complete reassembly, otherwise NULL
 116  * @*buf:     in:  the buffer to append. Always defined
 117  *            out: head buf after successful complete reassembly, otherwise NULL
 118  * Returns 1 when reassembly complete, otherwise 0
 119  */
 120 int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
 121 {
 122         struct sk_buff *head = *headbuf;
 123         struct sk_buff *frag = *buf;
 124         struct sk_buff *tail = NULL;
 125         struct tipc_msg *msg;
 126         u32 fragid;
 127         int delta;
 128         bool headstolen;
 129
 130         if (!frag)
 131                 goto err;
 132
 133         msg = buf_msg(frag);
 134         fragid = msg_type(msg);
 135         frag->next = NULL;
 136         skb_pull(frag, msg_hdr_sz(msg));
 137
 138         if (fragid == FIRST_FRAGMENT) {
 139                 if (unlikely(head))
 140                         goto err;
 141                 if (unlikely(skb_unclone(frag, GFP_ATOMIC)))
 142                         goto err;
 143                 head = *headbuf = frag;
 144                 *buf = NULL;
 145                 TIPC_SKB_CB(head)->tail = NULL;
 146                 if (skb_is_nonlinear(head)) {
 147                         skb_walk_frags(head, tail) {
 148                                 TIPC_SKB_CB(head)->tail = tail;
 149                         }
 150                 } else {
 151                         skb_frag_list_init(head);
 152                 }
 153                 return 0;
 154         }
 155
 156         if (!head)
 157                 goto err;
 158
 159         if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
 160                 kfree_skb_partial(frag, headstolen);
 161         } else {
 162                 tail = TIPC_SKB_CB(head)->tail;
 163                 if (!skb_has_frag_list(head))
 164                         skb_shinfo(head)->frag_list = frag;
 165                 else
 166                         tail->next = frag;
 167                 head->truesize += frag->truesize;
 168                 head->data_len += frag->len;
 169                 head->len += frag->len;
 170                 TIPC_SKB_CB(head)->tail = frag;
 171         }
 172
 173         if (fragid == LAST_FRAGMENT) {
 174                 TIPC_SKB_CB(head)->validated = false;
 175                 if (unlikely(!tipc_msg_validate(head)))
 176                         goto err;
 177                 *buf = head;
 178                 TIPC_SKB_CB(head)->tail = NULL;
 179                 *headbuf = NULL;
 180                 return 1;
 181         }
 182         *buf = NULL;
 183         return 0;
 184 err:
 185         kfree_skb(*buf);
 186         kfree_skb(*headbuf);
 187         *buf = *headbuf = NULL;
 188         return 0;
 189 }
 190
 191 /* tipc_msg_validate - validate basic format of received message
 192  *
 193  * This routine ensures a TIPC message has an acceptable header, and at least
 194  * as much data as the header indicates it should.  The routine also ensures
 195  * that the entire message header is stored in the main fragment of the message
 196  * buffer, to simplify future access to message header fields.
 197  *
 198  * Note: Having extra info present in the message header or data areas is OK.
 199  * TIPC will ignore the excess, under the assumption that it is optional info
 200  * introduced by a later release of the protocol.
 201  */
 202 bool tipc_msg_validate(struct sk_buff *skb)
 203 {
 204         struct tipc_msg *msg;
 205         int msz, hsz;
 206
 207         if (unlikely(TIPC_SKB_CB(skb)->validated))
 208                 return true;
 209         if (unlikely(!pskb_may_pull(skb, MIN_H_SIZE)))
 210                 return false;
 211
 212         hsz = msg_hdr_sz(buf_msg(skb));
 213         if (unlikely(hsz < MIN_H_SIZE) || (hsz > MAX_H_SIZE))
 214                 return false;
 215         if (unlikely(!pskb_may_pull(skb, hsz)))
 216                 return false;
 217
 218         msg = buf_msg(skb);
 219         if (unlikely(msg_version(msg) != TIPC_VERSION))
 220                 return false;
 221
 222         msz = msg_size(msg);
 223         if (unlikely(msz < hsz))
 224                 return false;
 225         if (unlikely((msz - hsz) > TIPC_MAX_USER_MSG_SIZE))
 226                 return false;
 227         if (unlikely(skb->len < msz))
 228                 return false;
 229
 230         TIPC_SKB_CB(skb)->validated = true;
 231         return true;
 232 }
 233
 234 /**
 235  * tipc_msg_build - create buffer chain containing specified header and data
 236  * @mhdr: Message header, to be prepended to data
 237  * @m: User message
 238  * @dsz: Total length of user data
 239  * @pktmax: Max packet size that can be used
 240  * @list: Buffer or chain of buffers to be returned to caller
 241  *
 242  * Returns message data size or errno: -ENOMEM, -EFAULT
 243  */
 244 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m,
 245                    int offset, int dsz, int pktmax, struct sk_buff_head *list)
 246 {
 247         int mhsz = msg_hdr_sz(mhdr);
 248         int msz = mhsz + dsz;
 249         int pktno = 1;
 250         int pktsz;
 251         int pktrem = pktmax;
 252         int drem = dsz;
 253         struct tipc_msg pkthdr;
 254         struct sk_buff *skb;
 255         char *pktpos;
 256         int rc;
 257
 258         msg_set_size(mhdr, msz);
 259
 260         /* No fragmentation needed? */
 261         if (likely(msz <= pktmax)) {
 262                 skb = tipc_buf_acquire(msz);
 263                 if (unlikely(!skb))
 264                         return -ENOMEM;
 265                 skb_orphan(skb);
 266                 __skb_queue_tail(list, skb);
 267                 skb_copy_to_linear_data(skb, mhdr, mhsz);
 268                 pktpos = skb->data + mhsz;
 269                 if (copy_from_iter(pktpos, dsz, &m->msg_iter) == dsz)
 270                         return dsz;
 271                 rc = -EFAULT;
 272                 goto error;
 273         }
 274
 275         /* Prepare reusable fragment header */
 276         tipc_msg_init(msg_prevnode(mhdr), &pkthdr, MSG_FRAGMENTER,
 277                       FIRST_FRAGMENT, INT_H_SIZE, msg_destnode(mhdr));
 278         msg_set_size(&pkthdr, pktmax);
 279         msg_set_fragm_no(&pkthdr, pktno);
 280         msg_set_importance(&pkthdr, msg_importance(mhdr));
 281
 282         /* Prepare first fragment */
 283         skb = tipc_buf_acquire(pktmax);
 284         if (!skb)
 285                 return -ENOMEM;
 286         skb_orphan(skb);
 287         __skb_queue_tail(list, skb);
 288         pktpos = skb->data;
 289         skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
 290         pktpos += INT_H_SIZE;
 291         pktrem -= INT_H_SIZE;
 292         skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
 293         pktpos += mhsz;
 294         pktrem -= mhsz;
 295
 296         do {
 297                 if (drem < pktrem)
 298                         pktrem = drem;
 299
 300                 if (copy_from_iter(pktpos, pktrem, &m->msg_iter) != pktrem) {
 301                         rc = -EFAULT;
 302                         goto error;
 303                 }
 304                 drem -= pktrem;
 305
 306                 if (!drem)
 307                         break;
 308
 309                 /* Prepare new fragment: */
 310                 if (drem < (pktmax - INT_H_SIZE))
 311                         pktsz = drem + INT_H_SIZE;
 312                 else
 313                         pktsz = pktmax;
 314                 skb = tipc_buf_acquire(pktsz);
 315                 if (!skb) {
 316                         rc = -ENOMEM;
 317                         goto error;
 318                 }
 319                 skb_orphan(skb);
 320                 __skb_queue_tail(list, skb);
 321                 msg_set_type(&pkthdr, FRAGMENT);
 322                 msg_set_size(&pkthdr, pktsz);
 323                 msg_set_fragm_no(&pkthdr, ++pktno);
 324                 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
 325                 pktpos = skb->data + INT_H_SIZE;
 326                 pktrem = pktsz - INT_H_SIZE;
 327
 328         } while (1);
 329         msg_set_type(buf_msg(skb), LAST_FRAGMENT);
 330         return dsz;
 331 error:
 332         __skb_queue_purge(list);
 333         __skb_queue_head_init(list);
 334         return rc;
 335 }
 336
 337 /**
 338  * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
 339  * @skb: the buffer to append to ("bundle")
 340  * @msg:  message to be appended
 341  * @mtu:  max allowable size for the bundle buffer
 342  * Consumes buffer if successful
 343  * Returns true if bundling could be performed, otherwise false
 344  */
 345 bool tipc_msg_bundle(struct sk_buff *skb, struct tipc_msg *msg, u32 mtu)
 346 {
 347         struct tipc_msg *bmsg;
 348         unsigned int bsz;
 349         unsigned int msz = msg_size(msg);
 350         u32 start, pad;
 351         u32 max = mtu - INT_H_SIZE;
 352
 353         if (likely(msg_user(msg) == MSG_FRAGMENTER))
 354                 return false;
 355         if (!skb)
 356                 return false;
 357         bmsg = buf_msg(skb);
 358         bsz = msg_size(bmsg);
 359         start = align(bsz);
 360         pad = start - bsz;
 361
 362         if (unlikely(msg_user(msg) == TUNNEL_PROTOCOL))
 363                 return false;
 364         if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
 365                 return false;
 366         if (unlikely(msg_user(bmsg) != MSG_BUNDLER))
 367                 return false;
 368         if (unlikely(skb_tailroom(skb) < (pad + msz)))
 369                 return false;
 370         if (unlikely(max < (start + msz)))
 371                 return false;
 372         if ((msg_importance(msg) < TIPC_SYSTEM_IMPORTANCE) &&
 373             (msg_importance(bmsg) == TIPC_SYSTEM_IMPORTANCE))
 374                 return false;
 375
 376         skb_put(skb, pad + msz);
 377         skb_copy_to_linear_data_offset(skb, start, msg, msz);
 378         msg_set_size(bmsg, start + msz);
 379         msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
 380         return true;
 381 }
 382
 383 /**
 384  *  tipc_msg_extract(): extract bundled inner packet from buffer
 385  *  @skb: buffer to be extracted from.
 386  *  @iskb: extracted inner buffer, to be returned
 387  *  @pos: position in outer message of msg to be extracted.
 388  *        Returns position of next msg
 389  *  Consumes outer buffer when last packet extracted
 390  *  Returns true when when there is an extracted buffer, otherwise false
 391  */
 392 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
 393 {
 394         struct tipc_msg *msg;
 395         int imsz, offset;
 396
 397         *iskb = NULL;
 398         if (unlikely(skb_linearize(skb)))
 399                 goto none;
 400
 401         msg = buf_msg(skb);
 402         offset = msg_hdr_sz(msg) + *pos;
 403         if (unlikely(offset > (msg_size(msg) - MIN_H_SIZE)))
 404                 goto none;
 405
 406         *iskb = skb_clone(skb, GFP_ATOMIC);
 407         if (unlikely(!*iskb))
 408                 goto none;
 409         skb_pull(*iskb, offset);
 410         imsz = msg_size(buf_msg(*iskb));
 411         skb_trim(*iskb, imsz);
 412         if (unlikely(!tipc_msg_validate(*iskb)))
 413                 goto none;
 414         *pos += align(imsz);
 415         return true;
 416 none:
 417         kfree_skb(skb);
 418         kfree_skb(*iskb);
 419         *iskb = NULL;
 420         return false;
 421 }
 422
 423 /**
 424  * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
 425  * @list: the buffer chain, where head is the buffer to replace/append
 426  * @skb: buffer to be created, appended to and returned in case of success
 427  * @msg: message to be appended
 428  * @mtu: max allowable size for the bundle buffer, inclusive header
 429  * @dnode: destination node for message. (Not always present in header)
 430  * Returns true if success, otherwise false
 431  */
 432 bool tipc_msg_make_bundle(struct sk_buff **skb,  struct tipc_msg *msg,
 433                           u32 mtu, u32 dnode)
 434 {
 435         struct sk_buff *_skb;
 436         struct tipc_msg *bmsg;
 437         u32 msz = msg_size(msg);
 438         u32 max = mtu - INT_H_SIZE;
 439
 440         if (msg_user(msg) == MSG_FRAGMENTER)
 441                 return false;
 442         if (msg_user(msg) == TUNNEL_PROTOCOL)
 443                 return false;
 444         if (msg_user(msg) == BCAST_PROTOCOL)
 445                 return false;
 446         if (msz > (max / 2))
 447                 return false;
 448
 449         _skb = tipc_buf_acquire(max);
 450         if (!_skb)
 451                 return false;
 452
 453         skb_trim(_skb, INT_H_SIZE);
 454         bmsg = buf_msg(_skb);
 455         tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
 456                       INT_H_SIZE, dnode);
 457         if (msg_isdata(msg))
 458                 msg_set_importance(bmsg, TIPC_CRITICAL_IMPORTANCE);
 459         else
 460                 msg_set_importance(bmsg, TIPC_SYSTEM_IMPORTANCE);
 461         msg_set_seqno(bmsg, msg_seqno(msg));
 462         msg_set_ack(bmsg, msg_ack(msg));
 463         msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
 464         tipc_msg_bundle(_skb, msg, mtu);
 465         *skb = _skb;
 466         return true;
 467 }
 468
 469 /**
 470  * tipc_msg_reverse(): swap source and destination addresses and add error code
 471  * @own_node: originating node id for reversed message
 472  * @skb:  buffer containing message to be reversed; may be replaced.
 473  * @err:  error code to be set in message, if any
 474  * Consumes buffer at failure
 475  * Returns true if success, otherwise false
 476  */
 477 bool tipc_msg_reverse(u32 own_node,  struct sk_buff **skb, int err)
 478 {
 479         struct sk_buff *_skb = *skb;
 480         struct tipc_msg *hdr = buf_msg(_skb);
 481         struct tipc_msg ohdr;
 482         int dlen = min_t(uint, msg_data_sz(hdr), MAX_FORWARD_SIZE);
 483
 484         if (skb_linearize(_skb))
 485                 goto exit;
 486         hdr = buf_msg(_skb);
 487         if (msg_dest_droppable(hdr))
 488                 goto exit;
 489         if (msg_errcode(hdr))
 490                 goto exit;
 491
 492         /* Take a copy of original header before altering message */
 493         memcpy(&ohdr, hdr, msg_hdr_sz(hdr));
 494
 495         /* Never return SHORT header; expand by replacing buffer if necessary */
 496         if (msg_short(hdr)) {
 497                 *skb = tipc_buf_acquire(BASIC_H_SIZE + dlen);
 498                 if (!*skb)
 499                         goto exit;
 500                 memcpy((*skb)->data + BASIC_H_SIZE, msg_data(hdr), dlen);
 501                 kfree_skb(_skb);
 502                 _skb = *skb;
 503                 hdr = buf_msg(_skb);
 504                 memcpy(hdr, &ohdr, BASIC_H_SIZE);
 505                 msg_set_hdr_sz(hdr, BASIC_H_SIZE);
 506         }
 507
 508         /* Now reverse the concerned fields */
 509         msg_set_errcode(hdr, err);
 510         msg_set_origport(hdr, msg_destport(&ohdr));
 511         msg_set_destport(hdr, msg_origport(&ohdr));
 512         msg_set_destnode(hdr, msg_prevnode(&ohdr));
 513         msg_set_prevnode(hdr, own_node);
 514         msg_set_orignode(hdr, own_node);
 515         msg_set_size(hdr, msg_hdr_sz(hdr) + dlen);
 516         skb_trim(_skb, msg_size(hdr));
 517         skb_orphan(_skb);
 518         return true;
 519 exit:
 520         kfree_skb(_skb);
 521         *skb = NULL;
 522         return false;
 523 }
 524
 525 /**
 526  * tipc_msg_lookup_dest(): try to find new destination for named message
 527  * @skb: the buffer containing the message.
 528  * @err: error code to be used by caller if lookup fails
 529  * Does not consume buffer
 530  * Returns true if a destination is found, false otherwise
 531  */
 532 bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, int *err)
 533 {
 534         struct tipc_msg *msg = buf_msg(skb);
 535         u32 dport, dnode;
 536         u32 onode = tipc_own_addr(net);
 537
 538         if (!msg_isdata(msg))
 539                 return false;
 540         if (!msg_named(msg))
 541                 return false;
 542         if (msg_errcode(msg))
 543                 return false;
 544         *err = -TIPC_ERR_NO_NAME;
 545         if (skb_linearize(skb))
 546                 return false;
 547         msg = buf_msg(skb);
 548         if (msg_reroute_cnt(msg))
 549                 return false;
 550         dnode = addr_domain(net, msg_lookup_scope(msg));
 551         dport = tipc_nametbl_translate(net, msg_nametype(msg),
 552                                        msg_nameinst(msg), &dnode);
 553         if (!dport)
 554                 return false;
 555         msg_incr_reroute_cnt(msg);
 556         if (dnode != onode)
 557                 msg_set_prevnode(msg, onode);
 558         msg_set_destnode(msg, dnode);
 559         msg_set_destport(msg, dport);
 560         *err = TIPC_OK;
 561         return true;
 562 }
 563
 564 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
 565  *                         reassemble the clones into one message
 566  */
 567 bool tipc_msg_reassemble(struct sk_buff_head *list, struct sk_buff_head *rcvq)
 568 {
 569         struct sk_buff *skb, *_skb;
 570         struct sk_buff *frag = NULL;
 571         struct sk_buff *head = NULL;
 572         int hdr_len;
 573
 574         /* Copy header if single buffer */
 575         if (skb_queue_len(list) == 1) {
 576                 skb = skb_peek(list);
 577                 hdr_len = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
 578                 _skb = __pskb_copy(skb, hdr_len, GFP_ATOMIC);
 579                 if (!_skb)
 580                         return false;
 581                 __skb_queue_tail(rcvq, _skb);
 582                 return true;
 583         }
 584
 585         /* Clone all fragments and reassemble */
 586         skb_queue_walk(list, skb) {
 587                 frag = skb_clone(skb, GFP_ATOMIC);
 588                 if (!frag)
 589                         goto error;
 590                 frag->next = NULL;
 591                 if (tipc_buf_append(&head, &frag))
 592                         break;
 593                 if (!head)
 594                         goto error;
 595         }
 596         __skb_queue_tail(rcvq, frag);
 597         return true;
 598 error:
 599         pr_warn("Failed do clone local mcast rcv buffer\n");
 600         kfree_skb(head);
 601         return false;
 602 }
 603
 604 /* tipc_skb_queue_sorted(); sort pkt into list according to sequence number
 605  * @list: list to be appended to
 606  * @seqno: sequence number of buffer to add
 607  * @skb: buffer to add
 608  */
 609 void __tipc_skb_queue_sorted(struct sk_buff_head *list, u16 seqno,
 610                              struct sk_buff *skb)
 611 {
 612         struct sk_buff *_skb, *tmp;
 613
 614         if (skb_queue_empty(list) || less(seqno, buf_seqno(skb_peek(list)))) {
 615                 __skb_queue_head(list, skb);
 616                 return;
 617         }
 618
 619         if (more(seqno, buf_seqno(skb_peek_tail(list)))) {
 620                 __skb_queue_tail(list, skb);
 621                 return;
 622         }
 623
 624         skb_queue_walk_safe(list, _skb, tmp) {
 625                 if (more(seqno, buf_seqno(_skb)))
 626                         continue;
 627                 if (seqno == buf_seqno(_skb))
 628                         break;
 629                 __skb_queue_before(list, _skb, skb);
 630                 return;
 631         }
 632         kfree_skb(skb);
 633 }