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
 47static 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 */
 61struct 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
 75void 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
 91struct 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 */
122int 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;
186err:
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 */
204bool 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 */
257int 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
299error:
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 */
318int 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;
415error:
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 */
429bool 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 */
476bool 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;
505none:
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 */
521bool 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 */
563bool 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;
609exit:
610	kfree_skb(_skb);
611	*skb = NULL;
612	return false;
613}
614
615bool 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 */
638bool 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 */
676bool 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 */
701bool 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;
732error:
733	pr_warn("Failed do clone local mcast rcv buffer\n");
734	kfree_skb(head);
735	return false;
736}
737
738bool 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 */
760void __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
786void 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}