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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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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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) {
144 if (skb_has_frag_list(frag) && __skb_linearize(frag))
146 frag = skb_unshare(frag, GFP_ATOMIC);
149 head = *headbuf = frag;
150 TIPC_SKB_CB(head)->tail = NULL;
157 if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
158 kfree_skb_partial(frag, headstolen);
160 tail = TIPC_SKB_CB(head)->tail;
161 if (!skb_has_frag_list(head))
162 skb_shinfo(head)->frag_list = frag;
165 head->truesize += frag->truesize;
166 head->data_len += frag->len;
167 head->len += frag->len;
168 TIPC_SKB_CB(head)->tail = frag;
171 if (fragid == LAST_FRAGMENT) {
172 TIPC_SKB_CB(head)->validated = false;
173 if (unlikely(!tipc_msg_validate(head)))
176 TIPC_SKB_CB(head)->tail = NULL;
185 *buf = *headbuf = NULL;
189 /* tipc_msg_validate - validate basic format of received message
191 * This routine ensures a TIPC message has an acceptable header, and at least
192 * as much data as the header indicates it should. The routine also ensures
193 * that the entire message header is stored in the main fragment of the message
194 * buffer, to simplify future access to message header fields.
196 * Note: Having extra info present in the message header or data areas is OK.
197 * TIPC will ignore the excess, under the assumption that it is optional info
198 * introduced by a later release of the protocol.
200 bool tipc_msg_validate(struct sk_buff *skb)
202 struct tipc_msg *msg;
205 if (unlikely(TIPC_SKB_CB(skb)->validated))
207 if (unlikely(!pskb_may_pull(skb, MIN_H_SIZE)))
210 hsz = msg_hdr_sz(buf_msg(skb));
211 if (unlikely(hsz < MIN_H_SIZE) || (hsz > MAX_H_SIZE))
213 if (unlikely(!pskb_may_pull(skb, hsz)))
217 if (unlikely(msg_version(msg) != TIPC_VERSION))
221 if (unlikely(msz < hsz))
223 if (unlikely((msz - hsz) > TIPC_MAX_USER_MSG_SIZE))
225 if (unlikely(skb->len < msz))
228 TIPC_SKB_CB(skb)->validated = true;
233 * tipc_msg_build - create buffer chain containing specified header and data
234 * @mhdr: Message header, to be prepended to data
236 * @dsz: Total length of user data
237 * @pktmax: Max packet size that can be used
238 * @list: Buffer or chain of buffers to be returned to caller
240 * Returns message data size or errno: -ENOMEM, -EFAULT
242 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m,
243 int offset, int dsz, int pktmax, struct sk_buff_head *list)
245 int mhsz = msg_hdr_sz(mhdr);
246 int msz = mhsz + dsz;
251 struct tipc_msg pkthdr;
256 msg_set_size(mhdr, msz);
258 /* No fragmentation needed? */
259 if (likely(msz <= pktmax)) {
260 skb = tipc_buf_acquire(msz, GFP_KERNEL);
264 __skb_queue_tail(list, skb);
265 skb_copy_to_linear_data(skb, mhdr, mhsz);
266 pktpos = skb->data + mhsz;
267 if (copy_from_iter_full(pktpos, dsz, &m->msg_iter))
273 /* Prepare reusable fragment header */
274 tipc_msg_init(msg_prevnode(mhdr), &pkthdr, MSG_FRAGMENTER,
275 FIRST_FRAGMENT, INT_H_SIZE, msg_destnode(mhdr));
276 msg_set_size(&pkthdr, pktmax);
277 msg_set_fragm_no(&pkthdr, pktno);
278 msg_set_importance(&pkthdr, msg_importance(mhdr));
280 /* Prepare first fragment */
281 skb = tipc_buf_acquire(pktmax, GFP_KERNEL);
285 __skb_queue_tail(list, skb);
287 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
288 pktpos += INT_H_SIZE;
289 pktrem -= INT_H_SIZE;
290 skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
298 if (!copy_from_iter_full(pktpos, pktrem, &m->msg_iter)) {
307 /* Prepare new fragment: */
308 if (drem < (pktmax - INT_H_SIZE))
309 pktsz = drem + INT_H_SIZE;
312 skb = tipc_buf_acquire(pktsz, GFP_KERNEL);
318 __skb_queue_tail(list, skb);
319 msg_set_type(&pkthdr, FRAGMENT);
320 msg_set_size(&pkthdr, pktsz);
321 msg_set_fragm_no(&pkthdr, ++pktno);
322 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
323 pktpos = skb->data + INT_H_SIZE;
324 pktrem = pktsz - INT_H_SIZE;
327 msg_set_type(buf_msg(skb), LAST_FRAGMENT);
330 __skb_queue_purge(list);
331 __skb_queue_head_init(list);
336 * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
337 * @skb: the buffer to append to ("bundle")
338 * @msg: message to be appended
339 * @mtu: max allowable size for the bundle buffer
340 * Consumes buffer if successful
341 * Returns true if bundling could be performed, otherwise false
343 bool tipc_msg_bundle(struct sk_buff *skb, struct tipc_msg *msg, u32 mtu)
345 struct tipc_msg *bmsg;
347 unsigned int msz = msg_size(msg);
349 u32 max = mtu - INT_H_SIZE;
351 if (likely(msg_user(msg) == MSG_FRAGMENTER))
356 bsz = msg_size(bmsg);
360 if (unlikely(msg_user(msg) == TUNNEL_PROTOCOL))
362 if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
364 if (unlikely(msg_user(bmsg) != MSG_BUNDLER))
366 if (unlikely(skb_tailroom(skb) < (pad + msz)))
368 if (unlikely(max < (start + msz)))
370 if ((msg_importance(msg) < TIPC_SYSTEM_IMPORTANCE) &&
371 (msg_importance(bmsg) == TIPC_SYSTEM_IMPORTANCE))
374 skb_put(skb, pad + msz);
375 skb_copy_to_linear_data_offset(skb, start, msg, msz);
376 msg_set_size(bmsg, start + msz);
377 msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
382 * tipc_msg_extract(): extract bundled inner packet from buffer
383 * @skb: buffer to be extracted from.
384 * @iskb: extracted inner buffer, to be returned
385 * @pos: position in outer message of msg to be extracted.
386 * Returns position of next msg
387 * Consumes outer buffer when last packet extracted
388 * Returns true when when there is an extracted buffer, otherwise false
390 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
392 struct tipc_msg *msg;
396 if (unlikely(skb_linearize(skb)))
400 offset = msg_hdr_sz(msg) + *pos;
401 if (unlikely(offset > (msg_size(msg) - MIN_H_SIZE)))
404 *iskb = skb_clone(skb, GFP_ATOMIC);
405 if (unlikely(!*iskb))
407 skb_pull(*iskb, offset);
408 imsz = msg_size(buf_msg(*iskb));
409 skb_trim(*iskb, imsz);
410 if (unlikely(!tipc_msg_validate(*iskb)))
422 * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
423 * @list: the buffer chain, where head is the buffer to replace/append
424 * @skb: buffer to be created, appended to and returned in case of success
425 * @msg: message to be appended
426 * @mtu: max allowable size for the bundle buffer, inclusive header
427 * @dnode: destination node for message. (Not always present in header)
428 * Returns true if success, otherwise false
430 bool tipc_msg_make_bundle(struct sk_buff **skb, struct tipc_msg *msg,
433 struct sk_buff *_skb;
434 struct tipc_msg *bmsg;
435 u32 msz = msg_size(msg);
436 u32 max = mtu - INT_H_SIZE;
438 if (msg_user(msg) == MSG_FRAGMENTER)
440 if (msg_user(msg) == TUNNEL_PROTOCOL)
442 if (msg_user(msg) == BCAST_PROTOCOL)
447 _skb = tipc_buf_acquire(max, GFP_ATOMIC);
451 skb_trim(_skb, INT_H_SIZE);
452 bmsg = buf_msg(_skb);
453 tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
455 msg_set_importance(bmsg, msg_importance(msg));
456 msg_set_seqno(bmsg, msg_seqno(msg));
457 msg_set_ack(bmsg, msg_ack(msg));
458 msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
459 tipc_msg_bundle(_skb, msg, mtu);
465 * tipc_msg_reverse(): swap source and destination addresses and add error code
466 * @own_node: originating node id for reversed message
467 * @skb: buffer containing message to be reversed; may be replaced.
468 * @err: error code to be set in message, if any
469 * Consumes buffer at failure
470 * Returns true if success, otherwise false
472 bool tipc_msg_reverse(u32 own_node, struct sk_buff **skb, int err)
474 struct sk_buff *_skb = *skb;
475 struct tipc_msg *hdr;
476 struct tipc_msg ohdr;
479 if (skb_linearize(_skb))
482 dlen = min_t(uint, msg_data_sz(hdr), MAX_FORWARD_SIZE);
483 if (msg_dest_droppable(hdr))
485 if (msg_errcode(hdr))
488 /* Take a copy of original header before altering message */
489 memcpy(&ohdr, hdr, msg_hdr_sz(hdr));
491 /* Never return SHORT header; expand by replacing buffer if necessary */
492 if (msg_short(hdr)) {
493 *skb = tipc_buf_acquire(BASIC_H_SIZE + dlen, GFP_ATOMIC);
496 memcpy((*skb)->data + BASIC_H_SIZE, msg_data(hdr), dlen);
500 memcpy(hdr, &ohdr, BASIC_H_SIZE);
501 msg_set_hdr_sz(hdr, BASIC_H_SIZE);
504 if (skb_cloned(_skb) &&
505 pskb_expand_head(_skb, BUF_HEADROOM, BUF_TAILROOM, GFP_ATOMIC))
508 /* reassign after skb header modifications */
510 /* Now reverse the concerned fields */
511 msg_set_errcode(hdr, err);
512 msg_set_non_seq(hdr, 0);
513 msg_set_origport(hdr, msg_destport(&ohdr));
514 msg_set_destport(hdr, msg_origport(&ohdr));
515 msg_set_destnode(hdr, msg_prevnode(&ohdr));
516 msg_set_prevnode(hdr, own_node);
517 msg_set_orignode(hdr, own_node);
518 msg_set_size(hdr, msg_hdr_sz(hdr) + dlen);
519 skb_trim(_skb, msg_size(hdr));
529 * tipc_msg_lookup_dest(): try to find new destination for named message
530 * @skb: the buffer containing the message.
531 * @err: error code to be used by caller if lookup fails
532 * Does not consume buffer
533 * Returns true if a destination is found, false otherwise
535 bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, int *err)
537 struct tipc_msg *msg = buf_msg(skb);
539 u32 onode = tipc_own_addr(net);
541 if (!msg_isdata(msg))
545 if (msg_errcode(msg))
547 *err = TIPC_ERR_NO_NAME;
548 if (skb_linearize(skb))
551 if (msg_reroute_cnt(msg))
553 dnode = addr_domain(net, msg_lookup_scope(msg));
554 dport = tipc_nametbl_translate(net, msg_nametype(msg),
555 msg_nameinst(msg), &dnode);
558 msg_incr_reroute_cnt(msg);
560 msg_set_prevnode(msg, onode);
561 msg_set_destnode(msg, dnode);
562 msg_set_destport(msg, dport);
565 if (!skb_cloned(skb))
568 /* Unclone buffer in case it was bundled */
569 if (pskb_expand_head(skb, BUF_HEADROOM, BUF_TAILROOM, GFP_ATOMIC))
575 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
576 * reassemble the clones into one message
578 bool tipc_msg_reassemble(struct sk_buff_head *list, struct sk_buff_head *rcvq)
580 struct sk_buff *skb, *_skb;
581 struct sk_buff *frag = NULL;
582 struct sk_buff *head = NULL;
585 /* Copy header if single buffer */
586 if (skb_queue_len(list) == 1) {
587 skb = skb_peek(list);
588 hdr_len = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
589 _skb = __pskb_copy(skb, hdr_len, GFP_ATOMIC);
592 __skb_queue_tail(rcvq, _skb);
596 /* Clone all fragments and reassemble */
597 skb_queue_walk(list, skb) {
598 frag = skb_clone(skb, GFP_ATOMIC);
602 if (tipc_buf_append(&head, &frag))
607 __skb_queue_tail(rcvq, frag);
610 pr_warn("Failed do clone local mcast rcv buffer\n");
615 bool tipc_msg_pskb_copy(u32 dst, struct sk_buff_head *msg,
616 struct sk_buff_head *cpy)
618 struct sk_buff *skb, *_skb;
620 skb_queue_walk(msg, skb) {
621 _skb = pskb_copy(skb, GFP_ATOMIC);
623 __skb_queue_purge(cpy);
626 msg_set_destnode(buf_msg(_skb), dst);
627 __skb_queue_tail(cpy, _skb);
632 /* tipc_skb_queue_sorted(); sort pkt into list according to sequence number
633 * @list: list to be appended to
634 * @seqno: sequence number of buffer to add
635 * @skb: buffer to add
637 void __tipc_skb_queue_sorted(struct sk_buff_head *list, u16 seqno,
640 struct sk_buff *_skb, *tmp;
642 if (skb_queue_empty(list) || less(seqno, buf_seqno(skb_peek(list)))) {
643 __skb_queue_head(list, skb);
647 if (more(seqno, buf_seqno(skb_peek_tail(list)))) {
648 __skb_queue_tail(list, skb);
652 skb_queue_walk_safe(list, _skb, tmp) {
653 if (more(seqno, buf_seqno(_skb)))
655 if (seqno == buf_seqno(_skb))
657 __skb_queue_before(list, _skb, skb);