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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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
45 static unsigned int align(unsigned int i)
51 * tipc_buf_acquire - creates a TIPC message buffer
52 * @size: message size (including TIPC header)
54 * Returns a new buffer with data pointers set to the specified size.
56 * NOTE: Headroom is reserved to allow prepending of a data link header.
57 * There may also be unrequested tailroom present at the buffer's end.
59 struct sk_buff *tipc_buf_acquire(u32 size)
62 unsigned int buf_size = (BUF_HEADROOM + size + 3) & ~3u;
64 skb = alloc_skb_fclone(buf_size, GFP_ATOMIC);
66 skb_reserve(skb, BUF_HEADROOM);
73 void tipc_msg_init(u32 own_node, struct tipc_msg *m, u32 user, u32 type,
78 msg_set_user(m, user);
79 msg_set_hdr_sz(m, hsize);
80 msg_set_size(m, hsize);
81 msg_set_prevnode(m, own_node);
82 msg_set_type(m, type);
83 if (hsize > SHORT_H_SIZE) {
84 msg_set_orignode(m, own_node);
85 msg_set_destnode(m, dnode);
89 struct sk_buff *tipc_msg_create(uint user, uint type,
90 uint hdr_sz, uint data_sz, u32 dnode,
91 u32 onode, u32 dport, u32 oport, int errcode)
96 buf = tipc_buf_acquire(hdr_sz + data_sz);
101 tipc_msg_init(onode, msg, user, type, hdr_sz, dnode);
102 msg_set_size(msg, hdr_sz + data_sz);
103 msg_set_origport(msg, oport);
104 msg_set_destport(msg, dport);
105 msg_set_errcode(msg, errcode);
106 if (hdr_sz > SHORT_H_SIZE) {
107 msg_set_orignode(msg, onode);
108 msg_set_destnode(msg, dnode);
113 /* tipc_buf_append(): Append a buffer to the fragment list of another buffer
114 * @*headbuf: in: NULL for first frag, otherwise value returned from prev call
115 * out: set when successful non-complete reassembly, otherwise NULL
116 * @*buf: in: the buffer to append. Always defined
117 * out: head buf after successful complete reassembly, otherwise NULL
118 * Returns 1 when reassembly complete, otherwise 0
120 int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
122 struct sk_buff *head = *headbuf;
123 struct sk_buff *frag = *buf;
124 struct sk_buff *tail = NULL;
125 struct tipc_msg *msg;
134 fragid = msg_type(msg);
136 skb_pull(frag, msg_hdr_sz(msg));
138 if (fragid == FIRST_FRAGMENT) {
141 if (unlikely(skb_unclone(frag, GFP_ATOMIC)))
143 head = *headbuf = frag;
145 TIPC_SKB_CB(head)->tail = NULL;
146 if (skb_is_nonlinear(head)) {
147 skb_walk_frags(head, tail) {
148 TIPC_SKB_CB(head)->tail = tail;
151 skb_frag_list_init(head);
159 if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
160 kfree_skb_partial(frag, headstolen);
162 tail = TIPC_SKB_CB(head)->tail;
163 if (!skb_has_frag_list(head))
164 skb_shinfo(head)->frag_list = frag;
167 head->truesize += frag->truesize;
168 head->data_len += frag->len;
169 head->len += frag->len;
170 TIPC_SKB_CB(head)->tail = frag;
173 if (fragid == LAST_FRAGMENT) {
174 TIPC_SKB_CB(head)->validated = false;
175 if (unlikely(!tipc_msg_validate(head)))
178 TIPC_SKB_CB(head)->tail = NULL;
185 pr_warn_ratelimited("Unable to build fragment list\n");
188 *buf = *headbuf = NULL;
192 /* tipc_msg_validate - validate basic format of received message
194 * This routine ensures a TIPC message has an acceptable header, and at least
195 * as much data as the header indicates it should. The routine also ensures
196 * that the entire message header is stored in the main fragment of the message
197 * buffer, to simplify future access to message header fields.
199 * Note: Having extra info present in the message header or data areas is OK.
200 * TIPC will ignore the excess, under the assumption that it is optional info
201 * introduced by a later release of the protocol.
203 bool tipc_msg_validate(struct sk_buff *skb)
205 struct tipc_msg *msg;
208 if (unlikely(TIPC_SKB_CB(skb)->validated))
210 if (unlikely(!pskb_may_pull(skb, MIN_H_SIZE)))
213 hsz = msg_hdr_sz(buf_msg(skb));
214 if (unlikely(hsz < MIN_H_SIZE) || (hsz > MAX_H_SIZE))
216 if (unlikely(!pskb_may_pull(skb, hsz)))
220 if (unlikely(msg_version(msg) != TIPC_VERSION))
224 if (unlikely(msz < hsz))
226 if (unlikely((msz - hsz) > TIPC_MAX_USER_MSG_SIZE))
228 if (unlikely(skb->len < msz))
231 TIPC_SKB_CB(skb)->validated = true;
236 * tipc_msg_build - create buffer chain containing specified header and data
237 * @mhdr: Message header, to be prepended to data
239 * @dsz: Total length of user data
240 * @pktmax: Max packet size that can be used
241 * @list: Buffer or chain of buffers to be returned to caller
243 * Returns message data size or errno: -ENOMEM, -EFAULT
245 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m,
246 int offset, int dsz, int pktmax, struct sk_buff_head *list)
248 int mhsz = msg_hdr_sz(mhdr);
249 int msz = mhsz + dsz;
254 struct tipc_msg pkthdr;
259 msg_set_size(mhdr, msz);
261 /* No fragmentation needed? */
262 if (likely(msz <= pktmax)) {
263 skb = tipc_buf_acquire(msz);
267 __skb_queue_tail(list, skb);
268 skb_copy_to_linear_data(skb, mhdr, mhsz);
269 pktpos = skb->data + mhsz;
270 if (copy_from_iter(pktpos, dsz, &m->msg_iter) == dsz)
276 /* Prepare reusable fragment header */
277 tipc_msg_init(msg_prevnode(mhdr), &pkthdr, MSG_FRAGMENTER,
278 FIRST_FRAGMENT, INT_H_SIZE, msg_destnode(mhdr));
279 msg_set_size(&pkthdr, pktmax);
280 msg_set_fragm_no(&pkthdr, pktno);
281 msg_set_importance(&pkthdr, msg_importance(mhdr));
283 /* Prepare first fragment */
284 skb = tipc_buf_acquire(pktmax);
288 __skb_queue_tail(list, skb);
290 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
291 pktpos += INT_H_SIZE;
292 pktrem -= INT_H_SIZE;
293 skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
301 if (copy_from_iter(pktpos, pktrem, &m->msg_iter) != pktrem) {
310 /* Prepare new fragment: */
311 if (drem < (pktmax - INT_H_SIZE))
312 pktsz = drem + INT_H_SIZE;
315 skb = tipc_buf_acquire(pktsz);
321 __skb_queue_tail(list, skb);
322 msg_set_type(&pkthdr, FRAGMENT);
323 msg_set_size(&pkthdr, pktsz);
324 msg_set_fragm_no(&pkthdr, ++pktno);
325 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
326 pktpos = skb->data + INT_H_SIZE;
327 pktrem = pktsz - INT_H_SIZE;
330 msg_set_type(buf_msg(skb), LAST_FRAGMENT);
333 __skb_queue_purge(list);
334 __skb_queue_head_init(list);
339 * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
340 * @skb: the buffer to append to ("bundle")
341 * @msg: message to be appended
342 * @mtu: max allowable size for the bundle buffer
343 * Consumes buffer if successful
344 * Returns true if bundling could be performed, otherwise false
346 bool tipc_msg_bundle(struct sk_buff *skb, struct tipc_msg *msg, u32 mtu)
348 struct tipc_msg *bmsg;
350 unsigned int msz = msg_size(msg);
352 u32 max = mtu - INT_H_SIZE;
354 if (likely(msg_user(msg) == MSG_FRAGMENTER))
359 bsz = msg_size(bmsg);
363 if (unlikely(msg_user(msg) == TUNNEL_PROTOCOL))
365 if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
367 if (unlikely(msg_user(bmsg) != MSG_BUNDLER))
369 if (unlikely(skb_tailroom(skb) < (pad + msz)))
371 if (unlikely(max < (start + msz)))
373 if ((msg_importance(msg) < TIPC_SYSTEM_IMPORTANCE) &&
374 (msg_importance(bmsg) == TIPC_SYSTEM_IMPORTANCE))
377 skb_put(skb, pad + msz);
378 skb_copy_to_linear_data_offset(skb, start, msg, msz);
379 msg_set_size(bmsg, start + msz);
380 msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
385 * tipc_msg_extract(): extract bundled inner packet from buffer
386 * @skb: buffer to be extracted from.
387 * @iskb: extracted inner buffer, to be returned
388 * @pos: position in outer message of msg to be extracted.
389 * Returns position of next msg
390 * Consumes outer buffer when last packet extracted
391 * Returns true when when there is an extracted buffer, otherwise false
393 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
395 struct tipc_msg *msg;
399 if (unlikely(skb_linearize(skb)))
403 offset = msg_hdr_sz(msg) + *pos;
404 if (unlikely(offset > (msg_size(msg) - MIN_H_SIZE)))
407 *iskb = skb_clone(skb, GFP_ATOMIC);
408 if (unlikely(!*iskb))
410 skb_pull(*iskb, offset);
411 imsz = msg_size(buf_msg(*iskb));
412 skb_trim(*iskb, imsz);
413 if (unlikely(!tipc_msg_validate(*iskb)))
425 * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
426 * @list: the buffer chain, where head is the buffer to replace/append
427 * @skb: buffer to be created, appended to and returned in case of success
428 * @msg: message to be appended
429 * @mtu: max allowable size for the bundle buffer, inclusive header
430 * @dnode: destination node for message. (Not always present in header)
431 * Returns true if success, otherwise false
433 bool tipc_msg_make_bundle(struct sk_buff **skb, struct tipc_msg *msg,
436 struct sk_buff *_skb;
437 struct tipc_msg *bmsg;
438 u32 msz = msg_size(msg);
439 u32 max = mtu - INT_H_SIZE;
441 if (msg_user(msg) == MSG_FRAGMENTER)
443 if (msg_user(msg) == TUNNEL_PROTOCOL)
445 if (msg_user(msg) == BCAST_PROTOCOL)
450 _skb = tipc_buf_acquire(max);
454 skb_trim(_skb, INT_H_SIZE);
455 bmsg = buf_msg(_skb);
456 tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
459 msg_set_importance(bmsg, TIPC_CRITICAL_IMPORTANCE);
461 msg_set_importance(bmsg, TIPC_SYSTEM_IMPORTANCE);
462 msg_set_seqno(bmsg, msg_seqno(msg));
463 msg_set_ack(bmsg, msg_ack(msg));
464 msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
465 tipc_msg_bundle(_skb, msg, mtu);
471 * tipc_msg_reverse(): swap source and destination addresses and add error code
472 * @own_node: originating node id for reversed message
473 * @skb: buffer containing message to be reversed; may be replaced.
474 * @err: error code to be set in message, if any
475 * Consumes buffer at failure
476 * Returns true if success, otherwise false
478 bool tipc_msg_reverse(u32 own_node, struct sk_buff **skb, int err)
480 struct sk_buff *_skb = *skb;
481 struct tipc_msg *hdr = buf_msg(_skb);
482 struct tipc_msg ohdr;
483 int dlen = min_t(uint, msg_data_sz(hdr), MAX_FORWARD_SIZE);
485 if (skb_linearize(_skb))
488 if (msg_dest_droppable(hdr))
490 if (msg_errcode(hdr))
493 /* Take a copy of original header before altering message */
494 memcpy(&ohdr, hdr, msg_hdr_sz(hdr));
496 /* Never return SHORT header; expand by replacing buffer if necessary */
497 if (msg_short(hdr)) {
498 *skb = tipc_buf_acquire(BASIC_H_SIZE + dlen);
501 memcpy((*skb)->data + BASIC_H_SIZE, msg_data(hdr), dlen);
505 memcpy(hdr, &ohdr, BASIC_H_SIZE);
506 msg_set_hdr_sz(hdr, BASIC_H_SIZE);
509 /* Now reverse the concerned fields */
510 msg_set_errcode(hdr, err);
511 msg_set_origport(hdr, msg_destport(&ohdr));
512 msg_set_destport(hdr, msg_origport(&ohdr));
513 msg_set_destnode(hdr, msg_prevnode(&ohdr));
514 msg_set_prevnode(hdr, own_node);
515 msg_set_orignode(hdr, own_node);
516 msg_set_size(hdr, msg_hdr_sz(hdr) + dlen);
517 skb_trim(_skb, msg_size(hdr));
527 * tipc_msg_lookup_dest(): try to find new destination for named message
528 * @skb: the buffer containing the message.
529 * @err: error code to be used by caller if lookup fails
530 * Does not consume buffer
531 * Returns true if a destination is found, false otherwise
533 bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, int *err)
535 struct tipc_msg *msg = buf_msg(skb);
537 u32 onode = tipc_own_addr(net);
539 if (!msg_isdata(msg))
543 if (msg_errcode(msg))
545 *err = -TIPC_ERR_NO_NAME;
546 if (skb_linearize(skb))
549 if (msg_reroute_cnt(msg))
551 dnode = addr_domain(net, msg_lookup_scope(msg));
552 dport = tipc_nametbl_translate(net, msg_nametype(msg),
553 msg_nameinst(msg), &dnode);
556 msg_incr_reroute_cnt(msg);
558 msg_set_prevnode(msg, onode);
559 msg_set_destnode(msg, dnode);
560 msg_set_destport(msg, dport);
565 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
566 * reassemble the clones into one message
568 struct sk_buff *tipc_msg_reassemble(struct sk_buff_head *list)
571 struct sk_buff *frag = NULL;
572 struct sk_buff *head = NULL;
575 /* Copy header if single buffer */
576 if (skb_queue_len(list) == 1) {
577 skb = skb_peek(list);
578 hdr_sz = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
579 return __pskb_copy(skb, hdr_sz, GFP_ATOMIC);
582 /* Clone all fragments and reassemble */
583 skb_queue_walk(list, skb) {
584 frag = skb_clone(skb, GFP_ATOMIC);
588 if (tipc_buf_append(&head, &frag))
595 pr_warn("Failed do clone local mcast rcv buffer\n");