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;
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;
144 skb_frag_list_init(head);
145 TIPC_SKB_CB(head)->tail = NULL;
153 if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
154 kfree_skb_partial(frag, headstolen);
156 tail = TIPC_SKB_CB(head)->tail;
157 if (!skb_has_frag_list(head))
158 skb_shinfo(head)->frag_list = frag;
161 head->truesize += frag->truesize;
162 head->data_len += frag->len;
163 head->len += frag->len;
164 TIPC_SKB_CB(head)->tail = frag;
167 if (fragid == LAST_FRAGMENT) {
168 TIPC_SKB_CB(head)->validated = false;
169 if (unlikely(!tipc_msg_validate(head)))
172 TIPC_SKB_CB(head)->tail = NULL;
179 pr_warn_ratelimited("Unable to build fragment list\n");
182 *buf = *headbuf = NULL;
186 /* tipc_msg_validate - validate basic format of received message
188 * This routine ensures a TIPC message has an acceptable header, and at least
189 * as much data as the header indicates it should. The routine also ensures
190 * that the entire message header is stored in the main fragment of the message
191 * buffer, to simplify future access to message header fields.
193 * Note: Having extra info present in the message header or data areas is OK.
194 * TIPC will ignore the excess, under the assumption that it is optional info
195 * introduced by a later release of the protocol.
197 bool tipc_msg_validate(struct sk_buff *skb)
199 struct tipc_msg *msg;
202 if (unlikely(TIPC_SKB_CB(skb)->validated))
204 if (unlikely(!pskb_may_pull(skb, MIN_H_SIZE)))
207 hsz = msg_hdr_sz(buf_msg(skb));
208 if (unlikely(hsz < MIN_H_SIZE) || (hsz > MAX_H_SIZE))
210 if (unlikely(!pskb_may_pull(skb, hsz)))
214 if (unlikely(msg_version(msg) != TIPC_VERSION))
218 if (unlikely(msz < hsz))
220 if (unlikely((msz - hsz) > TIPC_MAX_USER_MSG_SIZE))
222 if (unlikely(skb->len < msz))
225 TIPC_SKB_CB(skb)->validated = true;
230 * tipc_msg_build - create buffer chain containing specified header and data
231 * @mhdr: Message header, to be prepended to data
233 * @dsz: Total length of user data
234 * @pktmax: Max packet size that can be used
235 * @list: Buffer or chain of buffers to be returned to caller
237 * Returns message data size or errno: -ENOMEM, -EFAULT
239 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m,
240 int offset, int dsz, int pktmax, struct sk_buff_head *list)
242 int mhsz = msg_hdr_sz(mhdr);
243 int msz = mhsz + dsz;
248 struct tipc_msg pkthdr;
253 msg_set_size(mhdr, msz);
255 /* No fragmentation needed? */
256 if (likely(msz <= pktmax)) {
257 skb = tipc_buf_acquire(msz);
261 __skb_queue_tail(list, skb);
262 skb_copy_to_linear_data(skb, mhdr, mhsz);
263 pktpos = skb->data + mhsz;
264 if (copy_from_iter(pktpos, dsz, &m->msg_iter) == dsz)
270 /* Prepare reusable fragment header */
271 tipc_msg_init(msg_prevnode(mhdr), &pkthdr, MSG_FRAGMENTER,
272 FIRST_FRAGMENT, INT_H_SIZE, msg_destnode(mhdr));
273 msg_set_size(&pkthdr, pktmax);
274 msg_set_fragm_no(&pkthdr, pktno);
275 msg_set_importance(&pkthdr, msg_importance(mhdr));
277 /* Prepare first fragment */
278 skb = tipc_buf_acquire(pktmax);
282 __skb_queue_tail(list, skb);
284 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
285 pktpos += INT_H_SIZE;
286 pktrem -= INT_H_SIZE;
287 skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
295 if (copy_from_iter(pktpos, pktrem, &m->msg_iter) != pktrem) {
304 /* Prepare new fragment: */
305 if (drem < (pktmax - INT_H_SIZE))
306 pktsz = drem + INT_H_SIZE;
309 skb = tipc_buf_acquire(pktsz);
315 __skb_queue_tail(list, skb);
316 msg_set_type(&pkthdr, FRAGMENT);
317 msg_set_size(&pkthdr, pktsz);
318 msg_set_fragm_no(&pkthdr, ++pktno);
319 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
320 pktpos = skb->data + INT_H_SIZE;
321 pktrem = pktsz - INT_H_SIZE;
324 msg_set_type(buf_msg(skb), LAST_FRAGMENT);
327 __skb_queue_purge(list);
328 __skb_queue_head_init(list);
333 * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
334 * @skb: the buffer to append to ("bundle")
335 * @msg: message to be appended
336 * @mtu: max allowable size for the bundle buffer
337 * Consumes buffer if successful
338 * Returns true if bundling could be performed, otherwise false
340 bool tipc_msg_bundle(struct sk_buff *skb, struct tipc_msg *msg, u32 mtu)
342 struct tipc_msg *bmsg;
344 unsigned int msz = msg_size(msg);
346 u32 max = mtu - INT_H_SIZE;
348 if (likely(msg_user(msg) == MSG_FRAGMENTER))
353 bsz = msg_size(bmsg);
357 if (unlikely(msg_user(msg) == TUNNEL_PROTOCOL))
359 if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
361 if (unlikely(msg_user(bmsg) != MSG_BUNDLER))
363 if (unlikely(skb_tailroom(skb) < (pad + msz)))
365 if (unlikely(max < (start + msz)))
367 if ((msg_importance(msg) < TIPC_SYSTEM_IMPORTANCE) &&
368 (msg_importance(bmsg) == TIPC_SYSTEM_IMPORTANCE))
371 skb_put(skb, pad + msz);
372 skb_copy_to_linear_data_offset(skb, start, msg, msz);
373 msg_set_size(bmsg, start + msz);
374 msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
379 * tipc_msg_extract(): extract bundled inner packet from buffer
380 * @skb: buffer to be extracted from.
381 * @iskb: extracted inner buffer, to be returned
382 * @pos: position in outer message of msg to be extracted.
383 * Returns position of next msg
384 * Consumes outer buffer when last packet extracted
385 * Returns true when when there is an extracted buffer, otherwise false
387 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
389 struct tipc_msg *msg;
393 if (unlikely(skb_linearize(skb)))
397 offset = msg_hdr_sz(msg) + *pos;
398 if (unlikely(offset > (msg_size(msg) - MIN_H_SIZE)))
401 *iskb = skb_clone(skb, GFP_ATOMIC);
402 if (unlikely(!*iskb))
404 skb_pull(*iskb, offset);
405 imsz = msg_size(buf_msg(*iskb));
406 skb_trim(*iskb, imsz);
407 if (unlikely(!tipc_msg_validate(*iskb)))
419 * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
420 * @list: the buffer chain, where head is the buffer to replace/append
421 * @skb: buffer to be created, appended to and returned in case of success
422 * @msg: message to be appended
423 * @mtu: max allowable size for the bundle buffer, inclusive header
424 * @dnode: destination node for message. (Not always present in header)
425 * Returns true if success, otherwise false
427 bool tipc_msg_make_bundle(struct sk_buff **skb, struct tipc_msg *msg,
430 struct sk_buff *_skb;
431 struct tipc_msg *bmsg;
432 u32 msz = msg_size(msg);
433 u32 max = mtu - INT_H_SIZE;
435 if (msg_user(msg) == MSG_FRAGMENTER)
437 if (msg_user(msg) == TUNNEL_PROTOCOL)
439 if (msg_user(msg) == BCAST_PROTOCOL)
444 _skb = tipc_buf_acquire(max);
448 skb_trim(_skb, INT_H_SIZE);
449 bmsg = buf_msg(_skb);
450 tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
453 msg_set_importance(bmsg, TIPC_CRITICAL_IMPORTANCE);
455 msg_set_importance(bmsg, TIPC_SYSTEM_IMPORTANCE);
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 = buf_msg(_skb);
476 struct tipc_msg ohdr;
477 int dlen = min_t(uint, msg_data_sz(hdr), MAX_FORWARD_SIZE);
479 if (skb_linearize(_skb))
482 if (msg_dest_droppable(hdr))
484 if (msg_errcode(hdr))
487 /* Take a copy of original header before altering message */
488 memcpy(&ohdr, hdr, msg_hdr_sz(hdr));
490 /* Never return SHORT header; expand by replacing buffer if necessary */
491 if (msg_short(hdr)) {
492 *skb = tipc_buf_acquire(BASIC_H_SIZE + dlen);
495 memcpy((*skb)->data + BASIC_H_SIZE, msg_data(hdr), dlen);
499 memcpy(hdr, &ohdr, BASIC_H_SIZE);
500 msg_set_hdr_sz(hdr, BASIC_H_SIZE);
503 /* Now reverse the concerned fields */
504 msg_set_errcode(hdr, err);
505 msg_set_origport(hdr, msg_destport(&ohdr));
506 msg_set_destport(hdr, msg_origport(&ohdr));
507 msg_set_destnode(hdr, msg_prevnode(&ohdr));
508 msg_set_prevnode(hdr, own_node);
509 msg_set_orignode(hdr, own_node);
510 msg_set_size(hdr, msg_hdr_sz(hdr) + dlen);
511 skb_trim(_skb, msg_size(hdr));
521 * tipc_msg_lookup_dest(): try to find new destination for named message
522 * @skb: the buffer containing the message.
523 * @err: error code to be used by caller if lookup fails
524 * Does not consume buffer
525 * Returns true if a destination is found, false otherwise
527 bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb, int *err)
529 struct tipc_msg *msg = buf_msg(skb);
531 u32 onode = tipc_own_addr(net);
533 if (!msg_isdata(msg))
537 if (msg_errcode(msg))
539 *err = -TIPC_ERR_NO_NAME;
540 if (skb_linearize(skb))
543 if (msg_reroute_cnt(msg))
545 dnode = addr_domain(net, msg_lookup_scope(msg));
546 dport = tipc_nametbl_translate(net, msg_nametype(msg),
547 msg_nameinst(msg), &dnode);
550 msg_incr_reroute_cnt(msg);
552 msg_set_prevnode(msg, onode);
553 msg_set_destnode(msg, dnode);
554 msg_set_destport(msg, dport);
559 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
560 * reassemble the clones into one message
562 struct sk_buff *tipc_msg_reassemble(struct sk_buff_head *list)
565 struct sk_buff *frag = NULL;
566 struct sk_buff *head = NULL;
569 /* Copy header if single buffer */
570 if (skb_queue_len(list) == 1) {
571 skb = skb_peek(list);
572 hdr_sz = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
573 return __pskb_copy(skb, hdr_sz, GFP_ATOMIC);
576 /* Clone all fragments and reassemble */
577 skb_queue_walk(list, skb) {
578 frag = skb_clone(skb, GFP_ATOMIC);
582 if (tipc_buf_append(&head, &frag))
589 pr_warn("Failed do clone local mcast rcv buffer\n");