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
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9 * modification, are permitted provided that the following conditions are met:
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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.
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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_build - create buffer chain containing specified header and data
248 * @mhdr: Message header, to be prepended to data
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
254 * Note that the recursive call we are making here is safe, since it can
255 * logically go only one further level down.
257 * Returns message data size or errno: -ENOMEM, -EFAULT
259 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m, int offset,
260 int dsz, int pktmax, struct sk_buff_head *list)
262 int mhsz = msg_hdr_sz(mhdr);
263 struct tipc_msg pkthdr;
264 int msz = mhsz + dsz;
273 msg_set_size(mhdr, msz);
275 /* No fragmentation needed? */
276 if (likely(msz <= pktmax)) {
277 skb = tipc_buf_acquire(msz, GFP_KERNEL);
279 /* Fall back to smaller MTU if node local message */
280 if (unlikely(!skb)) {
281 if (pktmax != MAX_MSG_SIZE)
283 rc = tipc_msg_build(mhdr, m, offset, dsz, FB_MTU, list);
286 if (tipc_msg_assemble(list))
291 __skb_queue_tail(list, skb);
292 skb_copy_to_linear_data(skb, mhdr, mhsz);
293 pktpos = skb->data + mhsz;
294 if (copy_from_iter_full(pktpos, dsz, &m->msg_iter))
300 /* Prepare reusable fragment header */
301 tipc_msg_init(msg_prevnode(mhdr), &pkthdr, MSG_FRAGMENTER,
302 FIRST_FRAGMENT, INT_H_SIZE, msg_destnode(mhdr));
303 msg_set_size(&pkthdr, pktmax);
304 msg_set_fragm_no(&pkthdr, pktno);
305 msg_set_importance(&pkthdr, msg_importance(mhdr));
307 /* Prepare first fragment */
308 skb = tipc_buf_acquire(pktmax, GFP_KERNEL);
312 __skb_queue_tail(list, skb);
314 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
315 pktpos += INT_H_SIZE;
316 pktrem -= INT_H_SIZE;
317 skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
325 if (!copy_from_iter_full(pktpos, pktrem, &m->msg_iter)) {
334 /* Prepare new fragment: */
335 if (drem < (pktmax - INT_H_SIZE))
336 pktsz = drem + INT_H_SIZE;
339 skb = tipc_buf_acquire(pktsz, GFP_KERNEL);
345 __skb_queue_tail(list, skb);
346 msg_set_type(&pkthdr, FRAGMENT);
347 msg_set_size(&pkthdr, pktsz);
348 msg_set_fragm_no(&pkthdr, ++pktno);
349 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
350 pktpos = skb->data + INT_H_SIZE;
351 pktrem = pktsz - INT_H_SIZE;
354 msg_set_type(buf_msg(skb), LAST_FRAGMENT);
357 __skb_queue_purge(list);
358 __skb_queue_head_init(list);
363 * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
364 * @skb: the buffer to append to ("bundle")
365 * @msg: message to be appended
366 * @mtu: max allowable size for the bundle buffer
367 * Consumes buffer if successful
368 * Returns true if bundling could be performed, otherwise false
370 bool tipc_msg_bundle(struct sk_buff *skb, struct tipc_msg *msg, u32 mtu)
372 struct tipc_msg *bmsg;
374 unsigned int msz = msg_size(msg);
376 u32 max = mtu - INT_H_SIZE;
378 if (likely(msg_user(msg) == MSG_FRAGMENTER))
383 bsz = msg_size(bmsg);
387 if (unlikely(msg_user(msg) == TUNNEL_PROTOCOL))
389 if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
391 if (unlikely(msg_user(bmsg) != MSG_BUNDLER))
393 if (unlikely(skb_tailroom(skb) < (pad + msz)))
395 if (unlikely(max < (start + msz)))
397 if ((msg_importance(msg) < TIPC_SYSTEM_IMPORTANCE) &&
398 (msg_importance(bmsg) == TIPC_SYSTEM_IMPORTANCE))
401 skb_put(skb, pad + msz);
402 skb_copy_to_linear_data_offset(skb, start, msg, msz);
403 msg_set_size(bmsg, start + msz);
404 msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
409 * tipc_msg_extract(): extract bundled inner packet from buffer
410 * @skb: buffer to be extracted from.
411 * @iskb: extracted inner buffer, to be returned
412 * @pos: position in outer message of msg to be extracted.
413 * Returns position of next msg
414 * Consumes outer buffer when last packet extracted
415 * Returns true when when there is an extracted buffer, otherwise false
417 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
419 struct tipc_msg *hdr, *ihdr;
423 if (unlikely(skb_linearize(skb)))
427 if (unlikely(*pos > (msg_data_sz(hdr) - MIN_H_SIZE)))
430 ihdr = (struct tipc_msg *)(msg_data(hdr) + *pos);
431 imsz = msg_size(ihdr);
433 if ((*pos + imsz) > msg_data_sz(hdr))
436 *iskb = tipc_buf_acquire(imsz, GFP_ATOMIC);
440 skb_copy_to_linear_data(*iskb, ihdr, imsz);
441 if (unlikely(!tipc_msg_validate(iskb)))
454 * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
455 * @list: the buffer chain, where head is the buffer to replace/append
456 * @skb: buffer to be created, appended to and returned in case of success
457 * @msg: message to be appended
458 * @mtu: max allowable size for the bundle buffer, inclusive header
459 * @dnode: destination node for message. (Not always present in header)
460 * Returns true if success, otherwise false
462 bool tipc_msg_make_bundle(struct sk_buff **skb, struct tipc_msg *msg,
465 struct sk_buff *_skb;
466 struct tipc_msg *bmsg;
467 u32 msz = msg_size(msg);
468 u32 max = mtu - INT_H_SIZE;
470 if (msg_user(msg) == MSG_FRAGMENTER)
472 if (msg_user(msg) == TUNNEL_PROTOCOL)
474 if (msg_user(msg) == BCAST_PROTOCOL)
479 _skb = tipc_buf_acquire(max, GFP_ATOMIC);
483 skb_trim(_skb, INT_H_SIZE);
484 bmsg = buf_msg(_skb);
485 tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
488 msg_set_importance(bmsg, TIPC_CRITICAL_IMPORTANCE);
490 msg_set_importance(bmsg, TIPC_SYSTEM_IMPORTANCE);
491 msg_set_seqno(bmsg, msg_seqno(msg));
492 msg_set_ack(bmsg, msg_ack(msg));
493 msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
494 tipc_msg_bundle(_skb, msg, mtu);
500 * tipc_msg_reverse(): swap source and destination addresses and add error code
501 * @own_node: originating node id for reversed message
502 * @skb: buffer containing message to be reversed; will be consumed
503 * @err: error code to be set in message, if any
504 * Replaces consumed buffer with new one when successful
505 * Returns true if success, otherwise false
507 bool tipc_msg_reverse(u32 own_node, struct sk_buff **skb, int err)
509 struct sk_buff *_skb = *skb;
510 struct tipc_msg *_hdr, *hdr;
513 if (skb_linearize(_skb))
515 _hdr = buf_msg(_skb);
516 dlen = min_t(uint, msg_data_sz(_hdr), MAX_FORWARD_SIZE);
517 hlen = msg_hdr_sz(_hdr);
519 if (msg_dest_droppable(_hdr))
521 if (msg_errcode(_hdr))
524 /* Never return SHORT header */
525 if (hlen == SHORT_H_SIZE)
528 /* Don't return data along with SYN+, - sender has a clone */
529 if (msg_is_syn(_hdr) && err == TIPC_ERR_OVERLOAD)
532 /* Allocate new buffer to return */
533 *skb = tipc_buf_acquire(hlen + dlen, GFP_ATOMIC);
536 memcpy((*skb)->data, _skb->data, msg_hdr_sz(_hdr));
537 memcpy((*skb)->data + hlen, msg_data(_hdr), dlen);
539 /* Build reverse header in new buffer */
541 msg_set_hdr_sz(hdr, hlen);
542 msg_set_errcode(hdr, err);
543 msg_set_non_seq(hdr, 0);
544 msg_set_origport(hdr, msg_destport(_hdr));
545 msg_set_destport(hdr, msg_origport(_hdr));
546 msg_set_destnode(hdr, msg_prevnode(_hdr));
547 msg_set_prevnode(hdr, own_node);
548 msg_set_orignode(hdr, own_node);
549 msg_set_size(hdr, hlen + dlen);
559 bool tipc_msg_skb_clone(struct sk_buff_head *msg, struct sk_buff_head *cpy)
561 struct sk_buff *skb, *_skb;
563 skb_queue_walk(msg, skb) {
564 _skb = skb_clone(skb, GFP_ATOMIC);
566 __skb_queue_purge(cpy);
567 pr_err_ratelimited("Failed to clone buffer chain\n");
570 __skb_queue_tail(cpy, _skb);
576 * tipc_msg_lookup_dest(): try to find new destination for named message
577 * @skb: the buffer containing the message.
578 * @err: error code to be used by caller if lookup fails
579 * Does not consume buffer
580 * Returns true if a destination is found, false otherwise
582 bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, int *err)
584 struct tipc_msg *msg = buf_msg(skb);
586 u32 onode = tipc_own_addr(net);
588 if (!msg_isdata(msg))
592 if (msg_errcode(msg))
594 *err = TIPC_ERR_NO_NAME;
595 if (skb_linearize(skb))
598 if (msg_reroute_cnt(msg))
600 dnode = tipc_scope2node(net, msg_lookup_scope(msg));
601 dport = tipc_nametbl_translate(net, msg_nametype(msg),
602 msg_nameinst(msg), &dnode);
605 msg_incr_reroute_cnt(msg);
607 msg_set_prevnode(msg, onode);
608 msg_set_destnode(msg, dnode);
609 msg_set_destport(msg, dport);
612 if (!skb_cloned(skb))
618 /* tipc_msg_assemble() - assemble chain of fragments into one message
620 bool tipc_msg_assemble(struct sk_buff_head *list)
622 struct sk_buff *skb, *tmp = NULL;
624 if (skb_queue_len(list) == 1)
627 while ((skb = __skb_dequeue(list))) {
629 if (tipc_buf_append(&tmp, &skb)) {
630 __skb_queue_tail(list, skb);
636 __skb_queue_purge(list);
637 __skb_queue_head_init(list);
638 pr_warn("Failed do assemble buffer\n");
642 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
643 * reassemble the clones into one message
645 bool tipc_msg_reassemble(struct sk_buff_head *list, struct sk_buff_head *rcvq)
647 struct sk_buff *skb, *_skb;
648 struct sk_buff *frag = NULL;
649 struct sk_buff *head = NULL;
652 /* Copy header if single buffer */
653 if (skb_queue_len(list) == 1) {
654 skb = skb_peek(list);
655 hdr_len = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
656 _skb = __pskb_copy(skb, hdr_len, GFP_ATOMIC);
659 __skb_queue_tail(rcvq, _skb);
663 /* Clone all fragments and reassemble */
664 skb_queue_walk(list, skb) {
665 frag = skb_clone(skb, GFP_ATOMIC);
669 if (tipc_buf_append(&head, &frag))
674 __skb_queue_tail(rcvq, frag);
677 pr_warn("Failed do clone local mcast rcv buffer\n");
682 bool tipc_msg_pskb_copy(u32 dst, struct sk_buff_head *msg,
683 struct sk_buff_head *cpy)
685 struct sk_buff *skb, *_skb;
687 skb_queue_walk(msg, skb) {
688 _skb = pskb_copy(skb, GFP_ATOMIC);
690 __skb_queue_purge(cpy);
693 msg_set_destnode(buf_msg(_skb), dst);
694 __skb_queue_tail(cpy, _skb);
699 /* tipc_skb_queue_sorted(); sort pkt into list according to sequence number
700 * @list: list to be appended to
701 * @seqno: sequence number of buffer to add
702 * @skb: buffer to add
704 void __tipc_skb_queue_sorted(struct sk_buff_head *list, u16 seqno,
707 struct sk_buff *_skb, *tmp;
709 if (skb_queue_empty(list) || less(seqno, buf_seqno(skb_peek(list)))) {
710 __skb_queue_head(list, skb);
714 if (more(seqno, buf_seqno(skb_peek_tail(list)))) {
715 __skb_queue_tail(list, skb);
719 skb_queue_walk_safe(list, _skb, tmp) {
720 if (more(seqno, buf_seqno(_skb)))
722 if (seqno == buf_seqno(_skb))
724 __skb_queue_before(list, _skb, skb);
730 void tipc_skb_reject(struct net *net, int err, struct sk_buff *skb,
731 struct sk_buff_head *xmitq)
733 if (tipc_msg_reverse(tipc_own_addr(net), &skb, err))
734 __skb_queue_tail(xmitq, skb);