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_expand(skb, BUF_HEADROOM, 0, 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_fragment - build a fragment skb list for TIPC message
 248  *
 249  * @skb: TIPC message skb
 250  * @hdr: internal msg header to be put on the top of the fragments
 251  * @pktmax: max size of a fragment incl. the header
 252  * @frags: returned fragment skb list
 253  *
 254  * Returns 0 if the fragmentation is successful, otherwise: -EINVAL
 255  * or -ENOMEM
 256  */
 257 int tipc_msg_fragment(struct sk_buff *skb, const struct tipc_msg *hdr,
 258                       int pktmax, struct sk_buff_head *frags)
 259 {
 260         int pktno, nof_fragms, dsz, dmax, eat;
 261         struct tipc_msg *_hdr;
 262         struct sk_buff *_skb;
 263         u8 *data;
 264
 265         /* Non-linear buffer? */
 266         if (skb_linearize(skb))
 267                 return -ENOMEM;
 268
 269         data = (u8 *)skb->data;
 270         dsz = msg_size(buf_msg(skb));
 271         dmax = pktmax - INT_H_SIZE;
 272         if (dsz <= dmax || !dmax)
 273                 return -EINVAL;
 274
 275         nof_fragms = dsz / dmax + 1;
 276         for (pktno = 1; pktno <= nof_fragms; pktno++) {
 277                 if (pktno < nof_fragms)
 278                         eat = dmax;
 279                 else
 280                         eat = dsz % dmax;
 281                 /* Allocate a new fragment */
 282                 _skb = tipc_buf_acquire(INT_H_SIZE + eat, GFP_ATOMIC);
 283                 if (!_skb)
 284                         goto error;
 285                 skb_orphan(_skb);
 286                 __skb_queue_tail(frags, _skb);
 287                 /* Copy header & data to the fragment */
 288                 skb_copy_to_linear_data(_skb, hdr, INT_H_SIZE);
 289                 skb_copy_to_linear_data_offset(_skb, INT_H_SIZE, data, eat);
 290                 data += eat;
 291                 /* Update the fragment's header */
 292                 _hdr = buf_msg(_skb);
 293                 msg_set_fragm_no(_hdr, pktno);
 294                 msg_set_nof_fragms(_hdr, nof_fragms);
 295                 msg_set_size(_hdr, INT_H_SIZE + eat);
 296         }
 297         return 0;
 298
 299 error:
 300         __skb_queue_purge(frags);
 301         __skb_queue_head_init(frags);
 302         return -ENOMEM;
 303 }
 304
 305 /**
 306  * tipc_msg_build - create buffer chain containing specified header and data
 307  * @mhdr: Message header, to be prepended to data
 308  * @m: User message
 309  * @dsz: Total length of user data
 310  * @pktmax: Max packet size that can be used
 311  * @list: Buffer or chain of buffers to be returned to caller
 312  *
 313  * Note that the recursive call we are making here is safe, since it can
 314  * logically go only one further level down.
 315  *
 316  * Returns message data size or errno: -ENOMEM, -EFAULT
 317  */
 318 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m, int offset,
 319                    int dsz, int pktmax, struct sk_buff_head *list)
 320 {
 321         int mhsz = msg_hdr_sz(mhdr);
 322         struct tipc_msg pkthdr;
 323         int msz = mhsz + dsz;
 324         int pktrem = pktmax;
 325         struct sk_buff *skb;
 326         int drem = dsz;
 327         int pktno = 1;
 328         char *pktpos;
 329         int pktsz;
 330         int rc;
 331
 332         msg_set_size(mhdr, msz);
 333
 334         /* No fragmentation needed? */
 335         if (likely(msz <= pktmax)) {
 336                 skb = tipc_buf_acquire(msz, GFP_KERNEL);
 337
 338                 /* Fall back to smaller MTU if node local message */
 339                 if (unlikely(!skb)) {
 340                         if (pktmax != MAX_MSG_SIZE)
 341                                 return -ENOMEM;
 342                         rc = tipc_msg_build(mhdr, m, offset, dsz, FB_MTU, list);
 343                         if (rc != dsz)
 344                                 return rc;
 345                         if (tipc_msg_assemble(list))
 346                                 return dsz;
 347                         return -ENOMEM;
 348                 }
 349                 skb_orphan(skb);
 350                 __skb_queue_tail(list, skb);
 351                 skb_copy_to_linear_data(skb, mhdr, mhsz);
 352                 pktpos = skb->data + mhsz;
 353                 if (copy_from_iter_full(pktpos, dsz, &m->msg_iter))
 354                         return dsz;
 355                 rc = -EFAULT;
 356                 goto error;
 357         }
 358
 359         /* Prepare reusable fragment header */
 360         tipc_msg_init(msg_prevnode(mhdr), &pkthdr, MSG_FRAGMENTER,
 361                       FIRST_FRAGMENT, INT_H_SIZE, msg_destnode(mhdr));
 362         msg_set_size(&pkthdr, pktmax);
 363         msg_set_fragm_no(&pkthdr, pktno);
 364         msg_set_importance(&pkthdr, msg_importance(mhdr));
 365
 366         /* Prepare first fragment */
 367         skb = tipc_buf_acquire(pktmax, GFP_KERNEL);
 368         if (!skb)
 369                 return -ENOMEM;
 370         skb_orphan(skb);
 371         __skb_queue_tail(list, skb);
 372         pktpos = skb->data;
 373         skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
 374         pktpos += INT_H_SIZE;
 375         pktrem -= INT_H_SIZE;
 376         skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
 377         pktpos += mhsz;
 378         pktrem -= mhsz;
 379
 380         do {
 381                 if (drem < pktrem)
 382                         pktrem = drem;
 383
 384                 if (!copy_from_iter_full(pktpos, pktrem, &m->msg_iter)) {
 385                         rc = -EFAULT;
 386                         goto error;
 387                 }
 388                 drem -= pktrem;
 389
 390                 if (!drem)
 391                         break;
 392
 393                 /* Prepare new fragment: */
 394                 if (drem < (pktmax - INT_H_SIZE))
 395                         pktsz = drem + INT_H_SIZE;
 396                 else
 397                         pktsz = pktmax;
 398                 skb = tipc_buf_acquire(pktsz, GFP_KERNEL);
 399                 if (!skb) {
 400                         rc = -ENOMEM;
 401                         goto error;
 402                 }
 403                 skb_orphan(skb);
 404                 __skb_queue_tail(list, skb);
 405                 msg_set_type(&pkthdr, FRAGMENT);
 406                 msg_set_size(&pkthdr, pktsz);
 407                 msg_set_fragm_no(&pkthdr, ++pktno);
 408                 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
 409                 pktpos = skb->data + INT_H_SIZE;
 410                 pktrem = pktsz - INT_H_SIZE;
 411
 412         } while (1);
 413         msg_set_type(buf_msg(skb), LAST_FRAGMENT);
 414         return dsz;
 415 error:
 416         __skb_queue_purge(list);
 417         __skb_queue_head_init(list);
 418         return rc;
 419 }
 420
 421 /**
 422  * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
 423  * @skb: the buffer to append to ("bundle")
 424  * @msg:  message to be appended
 425  * @mtu:  max allowable size for the bundle buffer
 426  * Consumes buffer if successful
 427  * Returns true if bundling could be performed, otherwise false
 428  */
 429 bool tipc_msg_bundle(struct sk_buff *skb, struct tipc_msg *msg, u32 mtu)
 430 {
 431         struct tipc_msg *bmsg;
 432         unsigned int bsz;
 433         unsigned int msz = msg_size(msg);
 434         u32 start, pad;
 435         u32 max = mtu - INT_H_SIZE;
 436
 437         if (likely(msg_user(msg) == MSG_FRAGMENTER))
 438                 return false;
 439         if (!skb)
 440                 return false;
 441         bmsg = buf_msg(skb);
 442         bsz = msg_size(bmsg);
 443         start = align(bsz);
 444         pad = start - bsz;
 445
 446         if (unlikely(msg_user(msg) == TUNNEL_PROTOCOL))
 447                 return false;
 448         if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
 449                 return false;
 450         if (unlikely(msg_user(bmsg) != MSG_BUNDLER))
 451                 return false;
 452         if (unlikely(skb_tailroom(skb) < (pad + msz)))
 453                 return false;
 454         if (unlikely(max < (start + msz)))
 455                 return false;
 456         if ((msg_importance(msg) < TIPC_SYSTEM_IMPORTANCE) &&
 457             (msg_importance(bmsg) == TIPC_SYSTEM_IMPORTANCE))
 458                 return false;
 459
 460         skb_put(skb, pad + msz);
 461         skb_copy_to_linear_data_offset(skb, start, msg, msz);
 462         msg_set_size(bmsg, start + msz);
 463         msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
 464         return true;
 465 }
 466
 467 /**
 468  *  tipc_msg_extract(): extract bundled inner packet from buffer
 469  *  @skb: buffer to be extracted from.
 470  *  @iskb: extracted inner buffer, to be returned
 471  *  @pos: position in outer message of msg to be extracted.
 472  *        Returns position of next msg
 473  *  Consumes outer buffer when last packet extracted
 474  *  Returns true when when there is an extracted buffer, otherwise false
 475  */
 476 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
 477 {
 478         struct tipc_msg *hdr, *ihdr;
 479         int imsz;
 480
 481         *iskb = NULL;
 482         if (unlikely(skb_linearize(skb)))
 483                 goto none;
 484
 485         hdr = buf_msg(skb);
 486         if (unlikely(*pos > (msg_data_sz(hdr) - MIN_H_SIZE)))
 487                 goto none;
 488
 489         ihdr = (struct tipc_msg *)(msg_data(hdr) + *pos);
 490         imsz = msg_size(ihdr);
 491
 492         if ((*pos + imsz) > msg_data_sz(hdr))
 493                 goto none;
 494
 495         *iskb = tipc_buf_acquire(imsz, GFP_ATOMIC);
 496         if (!*iskb)
 497                 goto none;
 498
 499         skb_copy_to_linear_data(*iskb, ihdr, imsz);
 500         if (unlikely(!tipc_msg_validate(iskb)))
 501                 goto none;
 502
 503         *pos += align(imsz);
 504         return true;
 505 none:
 506         kfree_skb(skb);
 507         kfree_skb(*iskb);
 508         *iskb = NULL;
 509         return false;
 510 }
 511
 512 /**
 513  * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
 514  * @list: the buffer chain, where head is the buffer to replace/append
 515  * @skb: buffer to be created, appended to and returned in case of success
 516  * @msg: message to be appended
 517  * @mtu: max allowable size for the bundle buffer, inclusive header
 518  * @dnode: destination node for message. (Not always present in header)
 519  * Returns true if success, otherwise false
 520  */
 521 bool tipc_msg_make_bundle(struct sk_buff **skb,  struct tipc_msg *msg,
 522                           u32 mtu, u32 dnode)
 523 {
 524         struct sk_buff *_skb;
 525         struct tipc_msg *bmsg;
 526         u32 msz = msg_size(msg);
 527         u32 max = mtu - INT_H_SIZE;
 528
 529         if (msg_user(msg) == MSG_FRAGMENTER)
 530                 return false;
 531         if (msg_user(msg) == TUNNEL_PROTOCOL)
 532                 return false;
 533         if (msg_user(msg) == BCAST_PROTOCOL)
 534                 return false;
 535         if (msz > (max / 2))
 536                 return false;
 537
 538         _skb = tipc_buf_acquire(max, GFP_ATOMIC);
 539         if (!_skb)
 540                 return false;
 541
 542         skb_trim(_skb, INT_H_SIZE);
 543         bmsg = buf_msg(_skb);
 544         tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
 545                       INT_H_SIZE, dnode);
 546         msg_set_importance(bmsg, msg_importance(msg));
 547         msg_set_seqno(bmsg, msg_seqno(msg));
 548         msg_set_ack(bmsg, msg_ack(msg));
 549         msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
 550         tipc_msg_bundle(_skb, msg, mtu);
 551         *skb = _skb;
 552         return true;
 553 }
 554
 555 /**
 556  * tipc_msg_reverse(): swap source and destination addresses and add error code
 557  * @own_node: originating node id for reversed message
 558  * @skb:  buffer containing message to be reversed; will be consumed
 559  * @err:  error code to be set in message, if any
 560  * Replaces consumed buffer with new one when successful
 561  * Returns true if success, otherwise false
 562  */
 563 bool tipc_msg_reverse(u32 own_node,  struct sk_buff **skb, int err)
 564 {
 565         struct sk_buff *_skb = *skb;
 566         struct tipc_msg *_hdr, *hdr;
 567         int hlen, dlen;
 568
 569         if (skb_linearize(_skb))
 570                 goto exit;
 571         _hdr = buf_msg(_skb);
 572         dlen = min_t(uint, msg_data_sz(_hdr), MAX_FORWARD_SIZE);
 573         hlen = msg_hdr_sz(_hdr);
 574
 575         if (msg_dest_droppable(_hdr))
 576                 goto exit;
 577         if (msg_errcode(_hdr))
 578                 goto exit;
 579
 580         /* Never return SHORT header */
 581         if (hlen == SHORT_H_SIZE)
 582                 hlen = BASIC_H_SIZE;
 583
 584         /* Don't return data along with SYN+, - sender has a clone */
 585         if (msg_is_syn(_hdr) && err == TIPC_ERR_OVERLOAD)
 586                 dlen = 0;
 587
 588         /* Allocate new buffer to return */
 589         *skb = tipc_buf_acquire(hlen + dlen, GFP_ATOMIC);
 590         if (!*skb)
 591                 goto exit;
 592         memcpy((*skb)->data, _skb->data, msg_hdr_sz(_hdr));
 593         memcpy((*skb)->data + hlen, msg_data(_hdr), dlen);
 594
 595         /* Build reverse header in new buffer */
 596         hdr = buf_msg(*skb);
 597         msg_set_hdr_sz(hdr, hlen);
 598         msg_set_errcode(hdr, err);
 599         msg_set_non_seq(hdr, 0);
 600         msg_set_origport(hdr, msg_destport(_hdr));
 601         msg_set_destport(hdr, msg_origport(_hdr));
 602         msg_set_destnode(hdr, msg_prevnode(_hdr));
 603         msg_set_prevnode(hdr, own_node);
 604         msg_set_orignode(hdr, own_node);
 605         msg_set_size(hdr, hlen + dlen);
 606         skb_orphan(_skb);
 607         kfree_skb(_skb);
 608         return true;
 609 exit:
 610         kfree_skb(_skb);
 611         *skb = NULL;
 612         return false;
 613 }
 614
 615 bool tipc_msg_skb_clone(struct sk_buff_head *msg, struct sk_buff_head *cpy)
 616 {
 617         struct sk_buff *skb, *_skb;
 618
 619         skb_queue_walk(msg, skb) {
 620                 _skb = skb_clone(skb, GFP_ATOMIC);
 621                 if (!_skb) {
 622                         __skb_queue_purge(cpy);
 623                         pr_err_ratelimited("Failed to clone buffer chain\n");
 624                         return false;
 625                 }
 626                 __skb_queue_tail(cpy, _skb);
 627         }
 628         return true;
 629 }
 630
 631 /**
 632  * tipc_msg_lookup_dest(): try to find new destination for named message
 633  * @skb: the buffer containing the message.
 634  * @err: error code to be used by caller if lookup fails
 635  * Does not consume buffer
 636  * Returns true if a destination is found, false otherwise
 637  */
 638 bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, int *err)
 639 {
 640         struct tipc_msg *msg = buf_msg(skb);
 641         u32 dport, dnode;
 642         u32 onode = tipc_own_addr(net);
 643
 644         if (!msg_isdata(msg))
 645                 return false;
 646         if (!msg_named(msg))
 647                 return false;
 648         if (msg_errcode(msg))
 649                 return false;
 650         *err = TIPC_ERR_NO_NAME;
 651         if (skb_linearize(skb))
 652                 return false;
 653         msg = buf_msg(skb);
 654         if (msg_reroute_cnt(msg))
 655                 return false;
 656         dnode = tipc_scope2node(net, msg_lookup_scope(msg));
 657         dport = tipc_nametbl_translate(net, msg_nametype(msg),
 658                                        msg_nameinst(msg), &dnode);
 659         if (!dport)
 660                 return false;
 661         msg_incr_reroute_cnt(msg);
 662         if (dnode != onode)
 663                 msg_set_prevnode(msg, onode);
 664         msg_set_destnode(msg, dnode);
 665         msg_set_destport(msg, dport);
 666         *err = TIPC_OK;
 667
 668         if (!skb_cloned(skb))
 669                 return true;
 670
 671         return true;
 672 }
 673
 674 /* tipc_msg_assemble() - assemble chain of fragments into one message
 675  */
 676 bool tipc_msg_assemble(struct sk_buff_head *list)
 677 {
 678         struct sk_buff *skb, *tmp = NULL;
 679
 680         if (skb_queue_len(list) == 1)
 681                 return true;
 682
 683         while ((skb = __skb_dequeue(list))) {
 684                 skb->next = NULL;
 685                 if (tipc_buf_append(&tmp, &skb)) {
 686                         __skb_queue_tail(list, skb);
 687                         return true;
 688                 }
 689                 if (!tmp)
 690                         break;
 691         }
 692         __skb_queue_purge(list);
 693         __skb_queue_head_init(list);
 694         pr_warn("Failed do assemble buffer\n");
 695         return false;
 696 }
 697
 698 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
 699  *                         reassemble the clones into one message
 700  */
 701 bool tipc_msg_reassemble(struct sk_buff_head *list, struct sk_buff_head *rcvq)
 702 {
 703         struct sk_buff *skb, *_skb;
 704         struct sk_buff *frag = NULL;
 705         struct sk_buff *head = NULL;
 706         int hdr_len;
 707
 708         /* Copy header if single buffer */
 709         if (skb_queue_len(list) == 1) {
 710                 skb = skb_peek(list);
 711                 hdr_len = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
 712                 _skb = __pskb_copy(skb, hdr_len, GFP_ATOMIC);
 713                 if (!_skb)
 714                         return false;
 715                 __skb_queue_tail(rcvq, _skb);
 716                 return true;
 717         }
 718
 719         /* Clone all fragments and reassemble */
 720         skb_queue_walk(list, skb) {
 721                 frag = skb_clone(skb, GFP_ATOMIC);
 722                 if (!frag)
 723                         goto error;
 724                 frag->next = NULL;
 725                 if (tipc_buf_append(&head, &frag))
 726                         break;
 727                 if (!head)
 728                         goto error;
 729         }
 730         __skb_queue_tail(rcvq, frag);
 731         return true;
 732 error:
 733         pr_warn("Failed do clone local mcast rcv buffer\n");
 734         kfree_skb(head);
 735         return false;
 736 }
 737
 738 bool tipc_msg_pskb_copy(u32 dst, struct sk_buff_head *msg,
 739                         struct sk_buff_head *cpy)
 740 {
 741         struct sk_buff *skb, *_skb;
 742
 743         skb_queue_walk(msg, skb) {
 744                 _skb = pskb_copy(skb, GFP_ATOMIC);
 745                 if (!_skb) {
 746                         __skb_queue_purge(cpy);
 747                         return false;
 748                 }
 749                 msg_set_destnode(buf_msg(_skb), dst);
 750                 __skb_queue_tail(cpy, _skb);
 751         }
 752         return true;
 753 }
 754
 755 /* tipc_skb_queue_sorted(); sort pkt into list according to sequence number
 756  * @list: list to be appended to
 757  * @seqno: sequence number of buffer to add
 758  * @skb: buffer to add
 759  */
 760 void __tipc_skb_queue_sorted(struct sk_buff_head *list, u16 seqno,
 761                              struct sk_buff *skb)
 762 {
 763         struct sk_buff *_skb, *tmp;
 764
 765         if (skb_queue_empty(list) || less(seqno, buf_seqno(skb_peek(list)))) {
 766                 __skb_queue_head(list, skb);
 767                 return;
 768         }
 769
 770         if (more(seqno, buf_seqno(skb_peek_tail(list)))) {
 771                 __skb_queue_tail(list, skb);
 772                 return;
 773         }
 774
 775         skb_queue_walk_safe(list, _skb, tmp) {
 776                 if (more(seqno, buf_seqno(_skb)))
 777                         continue;
 778                 if (seqno == buf_seqno(_skb))
 779                         break;
 780                 __skb_queue_before(list, _skb, skb);
 781                 return;
 782         }
 783         kfree_skb(skb);
 784 }
 785
 786 void tipc_skb_reject(struct net *net, int err, struct sk_buff *skb,
 787                      struct sk_buff_head *xmitq)
 788 {
 789         if (tipc_msg_reverse(tipc_own_addr(net), &skb, err))
 790                 __skb_queue_tail(xmitq, skb);
 791 }