2 * net/tipc/msg.c: TIPC message header routines
4 * Copyright (c) 2000-2006, 2014-2015, Ericsson AB
5 * Copyright (c) 2005, 2010-2011, Wind River Systems
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions are met:
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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.
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.
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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34 * POSSIBILITY OF SUCH DAMAGE.
41 #include "name_table.h"
43 #define MAX_FORWARD_SIZE 1024
44 #define BUF_HEADROOM (LL_MAX_HEADER + 48)
45 #define BUF_TAILROOM 16
47 static unsigned int align(unsigned int i)
53 * tipc_buf_acquire - creates a TIPC message buffer
54 * @size: message size (including TIPC header)
56 * Returns a new buffer with data pointers set to the specified size.
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.
61 struct sk_buff *tipc_buf_acquire(u32 size, gfp_t gfp)
64 unsigned int buf_size = (BUF_HEADROOM + size + 3) & ~3u;
66 skb = alloc_skb_fclone(buf_size, gfp);
68 skb_reserve(skb, BUF_HEADROOM);
75 void tipc_msg_init(u32 own_node, struct tipc_msg *m, u32 user, u32 type,
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);
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)
98 buf = tipc_buf_acquire(hdr_sz + data_sz, GFP_ATOMIC);
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);
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
122 int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
124 struct sk_buff *head = *headbuf;
125 struct sk_buff *frag = *buf;
126 struct sk_buff *tail = NULL;
127 struct tipc_msg *msg;
136 fragid = msg_type(msg);
138 skb_pull(frag, msg_hdr_sz(msg));
140 if (fragid == FIRST_FRAGMENT) {
143 if (unlikely(skb_unclone(frag, GFP_ATOMIC)))
145 head = *headbuf = frag;
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;
153 skb_frag_list_init(head);
161 if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
162 kfree_skb_partial(frag, headstolen);
164 tail = TIPC_SKB_CB(head)->tail;
165 if (!skb_has_frag_list(head))
166 skb_shinfo(head)->frag_list = frag;
169 head->truesize += frag->truesize;
170 head->data_len += frag->len;
171 head->len += frag->len;
172 TIPC_SKB_CB(head)->tail = frag;
175 if (fragid == LAST_FRAGMENT) {
176 TIPC_SKB_CB(head)->validated = false;
177 if (unlikely(!tipc_msg_validate(&head)))
180 TIPC_SKB_CB(head)->tail = NULL;
189 *buf = *headbuf = NULL;
193 /* tipc_msg_validate - validate basic format of received message
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.
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.
204 bool tipc_msg_validate(struct sk_buff **_skb)
206 struct sk_buff *skb = *_skb;
207 struct tipc_msg *hdr;
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);
219 if (unlikely(TIPC_SKB_CB(skb)->validated))
221 if (unlikely(!pskb_may_pull(skb, MIN_H_SIZE)))
224 hsz = msg_hdr_sz(buf_msg(skb));
225 if (unlikely(hsz < MIN_H_SIZE) || (hsz > MAX_H_SIZE))
227 if (unlikely(!pskb_may_pull(skb, hsz)))
231 if (unlikely(msg_version(hdr) != TIPC_VERSION))
235 if (unlikely(msz < hsz))
237 if (unlikely((msz - hsz) > TIPC_MAX_USER_MSG_SIZE))
239 if (unlikely(skb->len < msz))
242 TIPC_SKB_CB(skb)->validated = true;
247 * tipc_msg_fragment - build a fragment skb list for TIPC message
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
254 * Returns 0 if the fragmentation is successful, otherwise: -EINVAL
257 int tipc_msg_fragment(struct sk_buff *skb, const struct tipc_msg *hdr,
258 int pktmax, struct sk_buff_head *frags)
260 int pktno, nof_fragms, dsz, dmax, eat;
261 struct tipc_msg *_hdr;
262 struct sk_buff *_skb;
265 /* Non-linear buffer? */
266 if (skb_linearize(skb))
269 data = (u8 *)skb->data;
270 dsz = msg_size(buf_msg(skb));
271 dmax = pktmax - INT_H_SIZE;
272 if (dsz <= dmax || !dmax)
275 nof_fragms = dsz / dmax + 1;
276 for (pktno = 1; pktno <= nof_fragms; pktno++) {
277 if (pktno < nof_fragms)
281 /* Allocate a new fragment */
282 _skb = tipc_buf_acquire(INT_H_SIZE + eat, GFP_ATOMIC);
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);
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);
300 __skb_queue_purge(frags);
301 __skb_queue_head_init(frags);
306 * tipc_msg_build - create buffer chain containing specified header and data
307 * @mhdr: Message header, to be prepended to data
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
313 * Note that the recursive call we are making here is safe, since it can
314 * logically go only one further level down.
316 * Returns message data size or errno: -ENOMEM, -EFAULT
318 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m, int offset,
319 int dsz, int pktmax, struct sk_buff_head *list)
321 int mhsz = msg_hdr_sz(mhdr);
322 struct tipc_msg pkthdr;
323 int msz = mhsz + dsz;
332 msg_set_size(mhdr, msz);
334 /* No fragmentation needed? */
335 if (likely(msz <= pktmax)) {
336 skb = tipc_buf_acquire(msz, GFP_KERNEL);
338 /* Fall back to smaller MTU if node local message */
339 if (unlikely(!skb)) {
340 if (pktmax != MAX_MSG_SIZE)
342 rc = tipc_msg_build(mhdr, m, offset, dsz, FB_MTU, list);
345 if (tipc_msg_assemble(list))
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))
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));
366 /* Prepare first fragment */
367 skb = tipc_buf_acquire(pktmax, GFP_KERNEL);
371 __skb_queue_tail(list, skb);
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);
384 if (!copy_from_iter_full(pktpos, pktrem, &m->msg_iter)) {
393 /* Prepare new fragment: */
394 if (drem < (pktmax - INT_H_SIZE))
395 pktsz = drem + INT_H_SIZE;
398 skb = tipc_buf_acquire(pktsz, GFP_KERNEL);
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;
413 msg_set_type(buf_msg(skb), LAST_FRAGMENT);
416 __skb_queue_purge(list);
417 __skb_queue_head_init(list);
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
429 bool tipc_msg_bundle(struct sk_buff *skb, struct tipc_msg *msg, u32 mtu)
431 struct tipc_msg *bmsg;
433 unsigned int msz = msg_size(msg);
435 u32 max = mtu - INT_H_SIZE;
437 if (likely(msg_user(msg) == MSG_FRAGMENTER))
442 bsz = msg_size(bmsg);
446 if (unlikely(msg_user(msg) == TUNNEL_PROTOCOL))
448 if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
450 if (unlikely(msg_user(bmsg) != MSG_BUNDLER))
452 if (unlikely(skb_tailroom(skb) < (pad + msz)))
454 if (unlikely(max < (start + msz)))
456 if ((msg_importance(msg) < TIPC_SYSTEM_IMPORTANCE) &&
457 (msg_importance(bmsg) == TIPC_SYSTEM_IMPORTANCE))
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);
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
476 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
478 struct tipc_msg *hdr, *ihdr;
482 if (unlikely(skb_linearize(skb)))
486 if (unlikely(*pos > (msg_data_sz(hdr) - MIN_H_SIZE)))
489 ihdr = (struct tipc_msg *)(msg_data(hdr) + *pos);
490 imsz = msg_size(ihdr);
492 if ((*pos + imsz) > msg_data_sz(hdr))
495 *iskb = tipc_buf_acquire(imsz, GFP_ATOMIC);
499 skb_copy_to_linear_data(*iskb, ihdr, imsz);
500 if (unlikely(!tipc_msg_validate(iskb)))
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
521 bool tipc_msg_make_bundle(struct sk_buff **skb, struct tipc_msg *msg,
524 struct sk_buff *_skb;
525 struct tipc_msg *bmsg;
526 u32 msz = msg_size(msg);
527 u32 max = mtu - INT_H_SIZE;
529 if (msg_user(msg) == MSG_FRAGMENTER)
531 if (msg_user(msg) == TUNNEL_PROTOCOL)
533 if (msg_user(msg) == BCAST_PROTOCOL)
538 _skb = tipc_buf_acquire(max, GFP_ATOMIC);
542 skb_trim(_skb, INT_H_SIZE);
543 bmsg = buf_msg(_skb);
544 tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
547 msg_set_importance(bmsg, TIPC_CRITICAL_IMPORTANCE);
549 msg_set_importance(bmsg, TIPC_SYSTEM_IMPORTANCE);
550 msg_set_seqno(bmsg, msg_seqno(msg));
551 msg_set_ack(bmsg, msg_ack(msg));
552 msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
553 tipc_msg_bundle(_skb, msg, mtu);
559 * tipc_msg_reverse(): swap source and destination addresses and add error code
560 * @own_node: originating node id for reversed message
561 * @skb: buffer containing message to be reversed; will be consumed
562 * @err: error code to be set in message, if any
563 * Replaces consumed buffer with new one when successful
564 * Returns true if success, otherwise false
566 bool tipc_msg_reverse(u32 own_node, struct sk_buff **skb, int err)
568 struct sk_buff *_skb = *skb;
569 struct tipc_msg *_hdr, *hdr;
572 if (skb_linearize(_skb))
574 _hdr = buf_msg(_skb);
575 dlen = min_t(uint, msg_data_sz(_hdr), MAX_FORWARD_SIZE);
576 hlen = msg_hdr_sz(_hdr);
578 if (msg_dest_droppable(_hdr))
580 if (msg_errcode(_hdr))
583 /* Never return SHORT header */
584 if (hlen == SHORT_H_SIZE)
587 /* Don't return data along with SYN+, - sender has a clone */
588 if (msg_is_syn(_hdr) && err == TIPC_ERR_OVERLOAD)
591 /* Allocate new buffer to return */
592 *skb = tipc_buf_acquire(hlen + dlen, GFP_ATOMIC);
595 memcpy((*skb)->data, _skb->data, msg_hdr_sz(_hdr));
596 memcpy((*skb)->data + hlen, msg_data(_hdr), dlen);
598 /* Build reverse header in new buffer */
600 msg_set_hdr_sz(hdr, hlen);
601 msg_set_errcode(hdr, err);
602 msg_set_non_seq(hdr, 0);
603 msg_set_origport(hdr, msg_destport(_hdr));
604 msg_set_destport(hdr, msg_origport(_hdr));
605 msg_set_destnode(hdr, msg_prevnode(_hdr));
606 msg_set_prevnode(hdr, own_node);
607 msg_set_orignode(hdr, own_node);
608 msg_set_size(hdr, hlen + dlen);
618 bool tipc_msg_skb_clone(struct sk_buff_head *msg, struct sk_buff_head *cpy)
620 struct sk_buff *skb, *_skb;
622 skb_queue_walk(msg, skb) {
623 _skb = skb_clone(skb, GFP_ATOMIC);
625 __skb_queue_purge(cpy);
626 pr_err_ratelimited("Failed to clone buffer chain\n");
629 __skb_queue_tail(cpy, _skb);
635 * tipc_msg_lookup_dest(): try to find new destination for named message
636 * @skb: the buffer containing the message.
637 * @err: error code to be used by caller if lookup fails
638 * Does not consume buffer
639 * Returns true if a destination is found, false otherwise
641 bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, int *err)
643 struct tipc_msg *msg = buf_msg(skb);
645 u32 onode = tipc_own_addr(net);
647 if (!msg_isdata(msg))
651 if (msg_errcode(msg))
653 *err = TIPC_ERR_NO_NAME;
654 if (skb_linearize(skb))
657 if (msg_reroute_cnt(msg))
659 dnode = tipc_scope2node(net, msg_lookup_scope(msg));
660 dport = tipc_nametbl_translate(net, msg_nametype(msg),
661 msg_nameinst(msg), &dnode);
664 msg_incr_reroute_cnt(msg);
666 msg_set_prevnode(msg, onode);
667 msg_set_destnode(msg, dnode);
668 msg_set_destport(msg, dport);
671 if (!skb_cloned(skb))
677 /* tipc_msg_assemble() - assemble chain of fragments into one message
679 bool tipc_msg_assemble(struct sk_buff_head *list)
681 struct sk_buff *skb, *tmp = NULL;
683 if (skb_queue_len(list) == 1)
686 while ((skb = __skb_dequeue(list))) {
688 if (tipc_buf_append(&tmp, &skb)) {
689 __skb_queue_tail(list, skb);
695 __skb_queue_purge(list);
696 __skb_queue_head_init(list);
697 pr_warn("Failed do assemble buffer\n");
701 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
702 * reassemble the clones into one message
704 bool tipc_msg_reassemble(struct sk_buff_head *list, struct sk_buff_head *rcvq)
706 struct sk_buff *skb, *_skb;
707 struct sk_buff *frag = NULL;
708 struct sk_buff *head = NULL;
711 /* Copy header if single buffer */
712 if (skb_queue_len(list) == 1) {
713 skb = skb_peek(list);
714 hdr_len = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
715 _skb = __pskb_copy(skb, hdr_len, GFP_ATOMIC);
718 __skb_queue_tail(rcvq, _skb);
722 /* Clone all fragments and reassemble */
723 skb_queue_walk(list, skb) {
724 frag = skb_clone(skb, GFP_ATOMIC);
728 if (tipc_buf_append(&head, &frag))
733 __skb_queue_tail(rcvq, frag);
736 pr_warn("Failed do clone local mcast rcv buffer\n");
741 bool tipc_msg_pskb_copy(u32 dst, struct sk_buff_head *msg,
742 struct sk_buff_head *cpy)
744 struct sk_buff *skb, *_skb;
746 skb_queue_walk(msg, skb) {
747 _skb = pskb_copy(skb, GFP_ATOMIC);
749 __skb_queue_purge(cpy);
752 msg_set_destnode(buf_msg(_skb), dst);
753 __skb_queue_tail(cpy, _skb);
758 /* tipc_skb_queue_sorted(); sort pkt into list according to sequence number
759 * @list: list to be appended to
760 * @seqno: sequence number of buffer to add
761 * @skb: buffer to add
763 void __tipc_skb_queue_sorted(struct sk_buff_head *list, u16 seqno,
766 struct sk_buff *_skb, *tmp;
768 if (skb_queue_empty(list) || less(seqno, buf_seqno(skb_peek(list)))) {
769 __skb_queue_head(list, skb);
773 if (more(seqno, buf_seqno(skb_peek_tail(list)))) {
774 __skb_queue_tail(list, skb);
778 skb_queue_walk_safe(list, _skb, tmp) {
779 if (more(seqno, buf_seqno(_skb)))
781 if (seqno == buf_seqno(_skb))
783 __skb_queue_before(list, _skb, skb);
789 void tipc_skb_reject(struct net *net, int err, struct sk_buff *skb,
790 struct sk_buff_head *xmitq)
792 if (tipc_msg_reverse(tipc_own_addr(net), &skb, err))
793 __skb_queue_tail(xmitq, skb);