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 #define BUF_HEADROOM (LL_MAX_HEADER + 48)
  45 #define BUF_TAILROOM 16
  46
  47 static unsigned int align(unsigned int i)
  48 {
  49         return (i + 3) & ~3u;
  50 }
  51
  52 /**
  53  * tipc_buf_acquire - creates a TIPC message buffer
  54  * @size: message size (including TIPC header)
  55  *
  56  * Returns a new buffer with data pointers set to the specified size.
  57  *
  58  * NOTE: Headroom is reserved to allow prepending of a data link header.
  59  *       There may also be unrequested tailroom present at the buffer's end.
  60  */
  61 struct sk_buff *tipc_buf_acquire(u32 size, gfp_t gfp)
  62 {
  63         struct sk_buff *skb;
  64         unsigned int buf_size = (BUF_HEADROOM + size + 3) & ~3u;
  65
  66         skb = alloc_skb_fclone(buf_size, gfp);
  67         if (skb) {
  68                 skb_reserve(skb, BUF_HEADROOM);
  69                 skb_put(skb, size);
  70                 skb->next = NULL;
  71         }
  72         return skb;
  73 }
  74
  75 void tipc_msg_init(u32 own_node, struct tipc_msg *m, u32 user, u32 type,
  76                    u32 hsize, u32 dnode)
  77 {
  78         memset(m, 0, hsize);
  79         msg_set_version(m);
  80         msg_set_user(m, user);
  81         msg_set_hdr_sz(m, hsize);
  82         msg_set_size(m, hsize);
  83         msg_set_prevnode(m, own_node);
  84         msg_set_type(m, type);
  85         if (hsize > SHORT_H_SIZE) {
  86                 msg_set_orignode(m, own_node);
  87                 msg_set_destnode(m, dnode);
  88         }
  89 }
  90
  91 struct sk_buff *tipc_msg_create(uint user, uint type,
  92                                 uint hdr_sz, uint data_sz, u32 dnode,
  93                                 u32 onode, u32 dport, u32 oport, int errcode)
  94 {
  95         struct tipc_msg *msg;
  96         struct sk_buff *buf;
  97
  98         buf = tipc_buf_acquire(hdr_sz + data_sz, GFP_ATOMIC);
  99         if (unlikely(!buf))
 100                 return NULL;
 101
 102         msg = buf_msg(buf);
 103         tipc_msg_init(onode, msg, user, type, hdr_sz, dnode);
 104         msg_set_size(msg, hdr_sz + data_sz);
 105         msg_set_origport(msg, oport);
 106         msg_set_destport(msg, dport);
 107         msg_set_errcode(msg, errcode);
 108         if (hdr_sz > SHORT_H_SIZE) {
 109                 msg_set_orignode(msg, onode);
 110                 msg_set_destnode(msg, dnode);
 111         }
 112         return buf;
 113 }
 114
 115 /* tipc_buf_append(): Append a buffer to the fragment list of another buffer
 116  * @*headbuf: in:  NULL for first frag, otherwise value returned from prev call
 117  *            out: set when successful non-complete reassembly, otherwise NULL
 118  * @*buf:     in:  the buffer to append. Always defined
 119  *            out: head buf after successful complete reassembly, otherwise NULL
 120  * Returns 1 when reassembly complete, otherwise 0
 121  */
 122 int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
 123 {
 124         struct sk_buff *head = *headbuf;
 125         struct sk_buff *frag = *buf;
 126         struct sk_buff *tail = NULL;
 127         struct tipc_msg *msg;
 128         u32 fragid;
 129         int delta;
 130         bool headstolen;
 131
 132         if (!frag)
 133                 goto err;
 134
 135         msg = buf_msg(frag);
 136         fragid = msg_type(msg);
 137         frag->next = NULL;
 138         skb_pull(frag, msg_hdr_sz(msg));
 139
 140         if (fragid == FIRST_FRAGMENT) {
 141                 if (unlikely(head))
 142                         goto err;
 143                 if (unlikely(skb_unclone(frag, GFP_ATOMIC)))
 144                         goto err;
 145                 head = *headbuf = frag;
 146                 *buf = NULL;
 147                 TIPC_SKB_CB(head)->tail = NULL;
 148                 if (skb_is_nonlinear(head)) {
 149                         skb_walk_frags(head, tail) {
 150                                 TIPC_SKB_CB(head)->tail = tail;
 151                         }
 152                 } else {
 153                         skb_frag_list_init(head);
 154                 }
 155                 return 0;
 156         }
 157
 158         if (!head)
 159                 goto err;
 160
 161         if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
 162                 kfree_skb_partial(frag, headstolen);
 163         } else {
 164                 tail = TIPC_SKB_CB(head)->tail;
 165                 if (!skb_has_frag_list(head))
 166                         skb_shinfo(head)->frag_list = frag;
 167                 else
 168                         tail->next = frag;
 169                 head->truesize += frag->truesize;
 170                 head->data_len += frag->len;
 171                 head->len += frag->len;
 172                 TIPC_SKB_CB(head)->tail = frag;
 173         }
 174
 175         if (fragid == LAST_FRAGMENT) {
 176                 TIPC_SKB_CB(head)->validated = false;
 177                 if (unlikely(!tipc_msg_validate(&head)))
 178                         goto err;
 179                 *buf = head;
 180                 TIPC_SKB_CB(head)->tail = NULL;
 181                 *headbuf = NULL;
 182                 return 1;
 183         }
 184         *buf = NULL;
 185         return 0;
 186 err:
 187         kfree_skb(*buf);
 188         kfree_skb(*headbuf);
 189         *buf = *headbuf = NULL;
 190         return 0;
 191 }
 192
 193 /* tipc_msg_validate - validate basic format of received message
 194  *
 195  * This routine ensures a TIPC message has an acceptable header, and at least
 196  * as much data as the header indicates it should.  The routine also ensures
 197  * that the entire message header is stored in the main fragment of the message
 198  * buffer, to simplify future access to message header fields.
 199  *
 200  * Note: Having extra info present in the message header or data areas is OK.
 201  * TIPC will ignore the excess, under the assumption that it is optional info
 202  * introduced by a later release of the protocol.
 203  */
 204 bool tipc_msg_validate(struct sk_buff **_skb)
 205 {
 206         struct sk_buff *skb = *_skb;
 207         struct tipc_msg *hdr;
 208         int msz, hsz;
 209
 210         /* Ensure that flow control ratio condition is satisfied */
 211         if (unlikely(skb->truesize / buf_roundup_len(skb) > 4)) {
 212                 skb = skb_copy(skb, GFP_ATOMIC);
 213                 if (!skb)
 214                         return false;
 215                 kfree_skb(*_skb);
 216                 *_skb = skb;
 217         }
 218
 219         if (unlikely(TIPC_SKB_CB(skb)->validated))
 220                 return true;
 221         if (unlikely(!pskb_may_pull(skb, MIN_H_SIZE)))
 222                 return false;
 223
 224         hsz = msg_hdr_sz(buf_msg(skb));
 225         if (unlikely(hsz < MIN_H_SIZE) || (hsz > MAX_H_SIZE))
 226                 return false;
 227         if (unlikely(!pskb_may_pull(skb, hsz)))
 228                 return false;
 229
 230         hdr = buf_msg(skb);
 231         if (unlikely(msg_version(hdr) != TIPC_VERSION))
 232                 return false;
 233
 234         msz = msg_size(hdr);
 235         if (unlikely(msz < hsz))
 236                 return false;
 237         if (unlikely((msz - hsz) > TIPC_MAX_USER_MSG_SIZE))
 238                 return false;
 239         if (unlikely(skb->len < msz))
 240                 return false;
 241
 242         TIPC_SKB_CB(skb)->validated = true;
 243         return true;
 244 }
 245
 246 /**
 247  * tipc_msg_build - create buffer chain containing specified header and data
 248  * @mhdr: Message header, to be prepended to data
 249  * @m: User message
 250  * @dsz: Total length of user data
 251  * @pktmax: Max packet size that can be used
 252  * @list: Buffer or chain of buffers to be returned to caller
 253  *
 254  * Returns message data size or errno: -ENOMEM, -EFAULT
 255  */
 256 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m,
 257                    int offset, int dsz, int pktmax, struct sk_buff_head *list)
 258 {
 259         int mhsz = msg_hdr_sz(mhdr);
 260         int msz = mhsz + dsz;
 261         int pktno = 1;
 262         int pktsz;
 263         int pktrem = pktmax;
 264         int drem = dsz;
 265         struct tipc_msg pkthdr;
 266         struct sk_buff *skb;
 267         char *pktpos;
 268         int rc;
 269
 270         msg_set_size(mhdr, msz);
 271
 272         /* No fragmentation needed? */
 273         if (likely(msz <= pktmax)) {
 274                 skb = tipc_buf_acquire(msz, GFP_KERNEL);
 275                 if (unlikely(!skb))
 276                         return -ENOMEM;
 277                 skb_orphan(skb);
 278                 __skb_queue_tail(list, skb);
 279                 skb_copy_to_linear_data(skb, mhdr, mhsz);
 280                 pktpos = skb->data + mhsz;
 281                 if (copy_from_iter_full(pktpos, dsz, &m->msg_iter))
 282                         return dsz;
 283                 rc = -EFAULT;
 284                 goto error;
 285         }
 286
 287         /* Prepare reusable fragment header */
 288         tipc_msg_init(msg_prevnode(mhdr), &pkthdr, MSG_FRAGMENTER,
 289                       FIRST_FRAGMENT, INT_H_SIZE, msg_destnode(mhdr));
 290         msg_set_size(&pkthdr, pktmax);
 291         msg_set_fragm_no(&pkthdr, pktno);
 292         msg_set_importance(&pkthdr, msg_importance(mhdr));
 293
 294         /* Prepare first fragment */
 295         skb = tipc_buf_acquire(pktmax, GFP_KERNEL);
 296         if (!skb)
 297                 return -ENOMEM;
 298         skb_orphan(skb);
 299         __skb_queue_tail(list, skb);
 300         pktpos = skb->data;
 301         skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
 302         pktpos += INT_H_SIZE;
 303         pktrem -= INT_H_SIZE;
 304         skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
 305         pktpos += mhsz;
 306         pktrem -= mhsz;
 307
 308         do {
 309                 if (drem < pktrem)
 310                         pktrem = drem;
 311
 312                 if (!copy_from_iter_full(pktpos, pktrem, &m->msg_iter)) {
 313                         rc = -EFAULT;
 314                         goto error;
 315                 }
 316                 drem -= pktrem;
 317
 318                 if (!drem)
 319                         break;
 320
 321                 /* Prepare new fragment: */
 322                 if (drem < (pktmax - INT_H_SIZE))
 323                         pktsz = drem + INT_H_SIZE;
 324                 else
 325                         pktsz = pktmax;
 326                 skb = tipc_buf_acquire(pktsz, GFP_KERNEL);
 327                 if (!skb) {
 328                         rc = -ENOMEM;
 329                         goto error;
 330                 }
 331                 skb_orphan(skb);
 332                 __skb_queue_tail(list, skb);
 333                 msg_set_type(&pkthdr, FRAGMENT);
 334                 msg_set_size(&pkthdr, pktsz);
 335                 msg_set_fragm_no(&pkthdr, ++pktno);
 336                 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
 337                 pktpos = skb->data + INT_H_SIZE;
 338                 pktrem = pktsz - INT_H_SIZE;
 339
 340         } while (1);
 341         msg_set_type(buf_msg(skb), LAST_FRAGMENT);
 342         return dsz;
 343 error:
 344         __skb_queue_purge(list);
 345         __skb_queue_head_init(list);
 346         return rc;
 347 }
 348
 349 /**
 350  * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
 351  * @skb: the buffer to append to ("bundle")
 352  * @msg:  message to be appended
 353  * @mtu:  max allowable size for the bundle buffer
 354  * Consumes buffer if successful
 355  * Returns true if bundling could be performed, otherwise false
 356  */
 357 bool tipc_msg_bundle(struct sk_buff *skb, struct tipc_msg *msg, u32 mtu)
 358 {
 359         struct tipc_msg *bmsg;
 360         unsigned int bsz;
 361         unsigned int msz = msg_size(msg);
 362         u32 start, pad;
 363         u32 max = mtu - INT_H_SIZE;
 364
 365         if (likely(msg_user(msg) == MSG_FRAGMENTER))
 366                 return false;
 367         if (!skb)
 368                 return false;
 369         bmsg = buf_msg(skb);
 370         bsz = msg_size(bmsg);
 371         start = align(bsz);
 372         pad = start - bsz;
 373
 374         if (unlikely(msg_user(msg) == TUNNEL_PROTOCOL))
 375                 return false;
 376         if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
 377                 return false;
 378         if (unlikely(msg_user(bmsg) != MSG_BUNDLER))
 379                 return false;
 380         if (unlikely(skb_tailroom(skb) < (pad + msz)))
 381                 return false;
 382         if (unlikely(max < (start + msz)))
 383                 return false;
 384         if ((msg_importance(msg) < TIPC_SYSTEM_IMPORTANCE) &&
 385             (msg_importance(bmsg) == TIPC_SYSTEM_IMPORTANCE))
 386                 return false;
 387
 388         skb_put(skb, pad + msz);
 389         skb_copy_to_linear_data_offset(skb, start, msg, msz);
 390         msg_set_size(bmsg, start + msz);
 391         msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
 392         return true;
 393 }
 394
 395 /**
 396  *  tipc_msg_extract(): extract bundled inner packet from buffer
 397  *  @skb: buffer to be extracted from.
 398  *  @iskb: extracted inner buffer, to be returned
 399  *  @pos: position in outer message of msg to be extracted.
 400  *        Returns position of next msg
 401  *  Consumes outer buffer when last packet extracted
 402  *  Returns true when when there is an extracted buffer, otherwise false
 403  */
 404 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
 405 {
 406         struct tipc_msg *msg;
 407         int imsz, offset;
 408
 409         *iskb = NULL;
 410         if (unlikely(skb_linearize(skb)))
 411                 goto none;
 412
 413         msg = buf_msg(skb);
 414         offset = msg_hdr_sz(msg) + *pos;
 415         if (unlikely(offset > (msg_size(msg) - MIN_H_SIZE)))
 416                 goto none;
 417
 418         *iskb = skb_clone(skb, GFP_ATOMIC);
 419         if (unlikely(!*iskb))
 420                 goto none;
 421         skb_pull(*iskb, offset);
 422         imsz = msg_size(buf_msg(*iskb));
 423         skb_trim(*iskb, imsz);
 424         if (unlikely(!tipc_msg_validate(iskb)))
 425                 goto none;
 426         *pos += align(imsz);
 427         return true;
 428 none:
 429         kfree_skb(skb);
 430         kfree_skb(*iskb);
 431         *iskb = NULL;
 432         return false;
 433 }
 434
 435 /**
 436  * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
 437  * @list: the buffer chain, where head is the buffer to replace/append
 438  * @skb: buffer to be created, appended to and returned in case of success
 439  * @msg: message to be appended
 440  * @mtu: max allowable size for the bundle buffer, inclusive header
 441  * @dnode: destination node for message. (Not always present in header)
 442  * Returns true if success, otherwise false
 443  */
 444 bool tipc_msg_make_bundle(struct sk_buff **skb,  struct tipc_msg *msg,
 445                           u32 mtu, u32 dnode)
 446 {
 447         struct sk_buff *_skb;
 448         struct tipc_msg *bmsg;
 449         u32 msz = msg_size(msg);
 450         u32 max = mtu - INT_H_SIZE;
 451
 452         if (msg_user(msg) == MSG_FRAGMENTER)
 453                 return false;
 454         if (msg_user(msg) == TUNNEL_PROTOCOL)
 455                 return false;
 456         if (msg_user(msg) == BCAST_PROTOCOL)
 457                 return false;
 458         if (msz > (max / 2))
 459                 return false;
 460
 461         _skb = tipc_buf_acquire(max, GFP_ATOMIC);
 462         if (!_skb)
 463                 return false;
 464
 465         skb_trim(_skb, INT_H_SIZE);
 466         bmsg = buf_msg(_skb);
 467         tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
 468                       INT_H_SIZE, dnode);
 469         if (msg_isdata(msg))
 470                 msg_set_importance(bmsg, TIPC_CRITICAL_IMPORTANCE);
 471         else
 472                 msg_set_importance(bmsg, TIPC_SYSTEM_IMPORTANCE);
 473         msg_set_seqno(bmsg, msg_seqno(msg));
 474         msg_set_ack(bmsg, msg_ack(msg));
 475         msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
 476         tipc_msg_bundle(_skb, msg, mtu);
 477         *skb = _skb;
 478         return true;
 479 }
 480
 481 /**
 482  * tipc_msg_reverse(): swap source and destination addresses and add error code
 483  * @own_node: originating node id for reversed message
 484  * @skb:  buffer containing message to be reversed; may be replaced.
 485  * @err:  error code to be set in message, if any
 486  * Consumes buffer at failure
 487  * Returns true if success, otherwise false
 488  */
 489 bool tipc_msg_reverse(u32 own_node,  struct sk_buff **skb, int err)
 490 {
 491         struct sk_buff *_skb = *skb;
 492         struct tipc_msg *hdr;
 493         struct tipc_msg ohdr;
 494         int dlen;
 495
 496         if (skb_linearize(_skb))
 497                 goto exit;
 498         hdr = buf_msg(_skb);
 499         dlen = min_t(uint, msg_data_sz(hdr), MAX_FORWARD_SIZE);
 500         if (msg_dest_droppable(hdr))
 501                 goto exit;
 502         if (msg_errcode(hdr))
 503                 goto exit;
 504
 505         /* Take a copy of original header before altering message */
 506         memcpy(&ohdr, hdr, msg_hdr_sz(hdr));
 507
 508         /* Never return SHORT header; expand by replacing buffer if necessary */
 509         if (msg_short(hdr)) {
 510                 *skb = tipc_buf_acquire(BASIC_H_SIZE + dlen, GFP_ATOMIC);
 511                 if (!*skb)
 512                         goto exit;
 513                 memcpy((*skb)->data + BASIC_H_SIZE, msg_data(hdr), dlen);
 514                 kfree_skb(_skb);
 515                 _skb = *skb;
 516                 hdr = buf_msg(_skb);
 517                 memcpy(hdr, &ohdr, BASIC_H_SIZE);
 518                 msg_set_hdr_sz(hdr, BASIC_H_SIZE);
 519         }
 520
 521         if (skb_cloned(_skb) &&
 522             pskb_expand_head(_skb, BUF_HEADROOM, BUF_TAILROOM, GFP_ATOMIC))
 523                 goto exit;
 524
 525         /* reassign after skb header modifications */
 526         hdr = buf_msg(_skb);
 527         /* Now reverse the concerned fields */
 528         msg_set_errcode(hdr, err);
 529         msg_set_non_seq(hdr, 0);
 530         msg_set_origport(hdr, msg_destport(&ohdr));
 531         msg_set_destport(hdr, msg_origport(&ohdr));
 532         msg_set_destnode(hdr, msg_prevnode(&ohdr));
 533         msg_set_prevnode(hdr, own_node);
 534         msg_set_orignode(hdr, own_node);
 535         msg_set_size(hdr, msg_hdr_sz(hdr) + dlen);
 536         skb_trim(_skb, msg_size(hdr));
 537         skb_orphan(_skb);
 538         return true;
 539 exit:
 540         kfree_skb(_skb);
 541         *skb = NULL;
 542         return false;
 543 }
 544
 545 /**
 546  * tipc_msg_lookup_dest(): try to find new destination for named message
 547  * @skb: the buffer containing the message.
 548  * @err: error code to be used by caller if lookup fails
 549  * Does not consume buffer
 550  * Returns true if a destination is found, false otherwise
 551  */
 552 bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, int *err)
 553 {
 554         struct tipc_msg *msg = buf_msg(skb);
 555         u32 dport, dnode;
 556         u32 onode = tipc_own_addr(net);
 557
 558         if (!msg_isdata(msg))
 559                 return false;
 560         if (!msg_named(msg))
 561                 return false;
 562         if (msg_errcode(msg))
 563                 return false;
 564         *err = TIPC_ERR_NO_NAME;
 565         if (skb_linearize(skb))
 566                 return false;
 567         msg = buf_msg(skb);
 568         if (msg_reroute_cnt(msg))
 569                 return false;
 570         dnode = addr_domain(net, msg_lookup_scope(msg));
 571         dport = tipc_nametbl_translate(net, msg_nametype(msg),
 572                                        msg_nameinst(msg), &dnode);
 573         if (!dport)
 574                 return false;
 575         msg_incr_reroute_cnt(msg);
 576         if (dnode != onode)
 577                 msg_set_prevnode(msg, onode);
 578         msg_set_destnode(msg, dnode);
 579         msg_set_destport(msg, dport);
 580         *err = TIPC_OK;
 581
 582         if (!skb_cloned(skb))
 583                 return true;
 584
 585         /* Unclone buffer in case it was bundled */
 586         if (pskb_expand_head(skb, BUF_HEADROOM, BUF_TAILROOM, GFP_ATOMIC))
 587                 return false;
 588
 589         return true;
 590 }
 591
 592 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
 593  *                         reassemble the clones into one message
 594  */
 595 bool tipc_msg_reassemble(struct sk_buff_head *list, struct sk_buff_head *rcvq)
 596 {
 597         struct sk_buff *skb, *_skb;
 598         struct sk_buff *frag = NULL;
 599         struct sk_buff *head = NULL;
 600         int hdr_len;
 601
 602         /* Copy header if single buffer */
 603         if (skb_queue_len(list) == 1) {
 604                 skb = skb_peek(list);
 605                 hdr_len = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
 606                 _skb = __pskb_copy(skb, hdr_len, GFP_ATOMIC);
 607                 if (!_skb)
 608                         return false;
 609                 __skb_queue_tail(rcvq, _skb);
 610                 return true;
 611         }
 612
 613         /* Clone all fragments and reassemble */
 614         skb_queue_walk(list, skb) {
 615                 frag = skb_clone(skb, GFP_ATOMIC);
 616                 if (!frag)
 617                         goto error;
 618                 frag->next = NULL;
 619                 if (tipc_buf_append(&head, &frag))
 620                         break;
 621                 if (!head)
 622                         goto error;
 623         }
 624         __skb_queue_tail(rcvq, frag);
 625         return true;
 626 error:
 627         pr_warn("Failed do clone local mcast rcv buffer\n");
 628         kfree_skb(head);
 629         return false;
 630 }
 631
 632 bool tipc_msg_pskb_copy(u32 dst, struct sk_buff_head *msg,
 633                         struct sk_buff_head *cpy)
 634 {
 635         struct sk_buff *skb, *_skb;
 636
 637         skb_queue_walk(msg, skb) {
 638                 _skb = pskb_copy(skb, GFP_ATOMIC);
 639                 if (!_skb) {
 640                         __skb_queue_purge(cpy);
 641                         return false;
 642                 }
 643                 msg_set_destnode(buf_msg(_skb), dst);
 644                 __skb_queue_tail(cpy, _skb);
 645         }
 646         return true;
 647 }
 648
 649 /* tipc_skb_queue_sorted(); sort pkt into list according to sequence number
 650  * @list: list to be appended to
 651  * @seqno: sequence number of buffer to add
 652  * @skb: buffer to add
 653  */
 654 void __tipc_skb_queue_sorted(struct sk_buff_head *list, u16 seqno,
 655                              struct sk_buff *skb)
 656 {
 657         struct sk_buff *_skb, *tmp;
 658
 659         if (skb_queue_empty(list) || less(seqno, buf_seqno(skb_peek(list)))) {
 660                 __skb_queue_head(list, skb);
 661                 return;
 662         }
 663
 664         if (more(seqno, buf_seqno(skb_peek_tail(list)))) {
 665                 __skb_queue_tail(list, skb);
 666                 return;
 667         }
 668
 669         skb_queue_walk_safe(list, _skb, tmp) {
 670                 if (more(seqno, buf_seqno(_skb)))
 671                         continue;
 672                 if (seqno == buf_seqno(_skb))
 673                         break;
 674                 __skb_queue_before(list, _skb, skb);
 675                 return;
 676         }
 677         kfree_skb(skb);
 678 }
 679
 680 void tipc_skb_reject(struct net *net, int err, struct sk_buff *skb,
 681                      struct sk_buff_head *xmitq)
 682 {
 683         if (tipc_msg_reverse(tipc_own_addr(net), &skb, err))
 684                 __skb_queue_tail(xmitq, skb);
 685 }