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
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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) {
169 TIPC_SKB_CB(head)->tail = NULL;
177 pr_warn_ratelimited("Unable to build fragment list\n");
180 *buf = *headbuf = NULL;
184 /* tipc_msg_validate - validate basic format of received message
186 * This routine ensures a TIPC message has an acceptable header, and at least
187 * as much data as the header indicates it should. The routine also ensures
188 * that the entire message header is stored in the main fragment of the message
189 * buffer, to simplify future access to message header fields.
191 * Note: Having extra info present in the message header or data areas is OK.
192 * TIPC will ignore the excess, under the assumption that it is optional info
193 * introduced by a later release of the protocol.
195 bool tipc_msg_validate(struct sk_buff *skb)
197 struct tipc_msg *msg;
200 if (unlikely(TIPC_SKB_CB(skb)->validated))
202 if (unlikely(!pskb_may_pull(skb, MIN_H_SIZE)))
205 hsz = msg_hdr_sz(buf_msg(skb));
206 if (unlikely(hsz < MIN_H_SIZE) || (hsz > MAX_H_SIZE))
208 if (unlikely(!pskb_may_pull(skb, hsz)))
212 if (unlikely(msg_version(msg) != TIPC_VERSION))
216 if (unlikely(msz < hsz))
218 if (unlikely((msz - hsz) > TIPC_MAX_USER_MSG_SIZE))
220 if (unlikely(skb->len < msz))
223 TIPC_SKB_CB(skb)->validated = true;
228 * tipc_msg_build - create buffer chain containing specified header and data
229 * @mhdr: Message header, to be prepended to data
231 * @dsz: Total length of user data
232 * @pktmax: Max packet size that can be used
233 * @list: Buffer or chain of buffers to be returned to caller
235 * Returns message data size or errno: -ENOMEM, -EFAULT
237 int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m,
238 int offset, int dsz, int pktmax, struct sk_buff_head *list)
240 int mhsz = msg_hdr_sz(mhdr);
241 int msz = mhsz + dsz;
246 struct tipc_msg pkthdr;
251 msg_set_size(mhdr, msz);
253 /* No fragmentation needed? */
254 if (likely(msz <= pktmax)) {
255 skb = tipc_buf_acquire(msz);
259 __skb_queue_tail(list, skb);
260 skb_copy_to_linear_data(skb, mhdr, mhsz);
261 pktpos = skb->data + mhsz;
262 if (copy_from_iter(pktpos, dsz, &m->msg_iter) == dsz)
268 /* Prepare reusable fragment header */
269 tipc_msg_init(msg_prevnode(mhdr), &pkthdr, MSG_FRAGMENTER,
270 FIRST_FRAGMENT, INT_H_SIZE, msg_destnode(mhdr));
271 msg_set_size(&pkthdr, pktmax);
272 msg_set_fragm_no(&pkthdr, pktno);
274 /* Prepare first fragment */
275 skb = tipc_buf_acquire(pktmax);
279 __skb_queue_tail(list, skb);
281 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
282 pktpos += INT_H_SIZE;
283 pktrem -= INT_H_SIZE;
284 skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
292 if (copy_from_iter(pktpos, pktrem, &m->msg_iter) != pktrem) {
301 /* Prepare new fragment: */
302 if (drem < (pktmax - INT_H_SIZE))
303 pktsz = drem + INT_H_SIZE;
306 skb = tipc_buf_acquire(pktsz);
312 __skb_queue_tail(list, skb);
313 msg_set_type(&pkthdr, FRAGMENT);
314 msg_set_size(&pkthdr, pktsz);
315 msg_set_fragm_no(&pkthdr, ++pktno);
316 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
317 pktpos = skb->data + INT_H_SIZE;
318 pktrem = pktsz - INT_H_SIZE;
321 msg_set_type(buf_msg(skb), LAST_FRAGMENT);
324 __skb_queue_purge(list);
325 __skb_queue_head_init(list);
330 * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
331 * @list: the buffer chain of the existing buffer ("bundle")
332 * @skb: buffer to be appended
333 * @mtu: max allowable size for the bundle buffer
334 * Consumes buffer if successful
335 * Returns true if bundling could be performed, otherwise false
337 bool tipc_msg_bundle(struct sk_buff_head *list, struct sk_buff *skb, u32 mtu)
339 struct sk_buff *bskb = skb_peek_tail(list);
340 struct tipc_msg *bmsg = buf_msg(bskb);
341 struct tipc_msg *msg = buf_msg(skb);
342 unsigned int bsz = msg_size(bmsg);
343 unsigned int msz = msg_size(msg);
344 u32 start = align(bsz);
345 u32 max = mtu - INT_H_SIZE;
346 u32 pad = start - bsz;
348 if (likely(msg_user(msg) == MSG_FRAGMENTER))
350 if (unlikely(msg_user(msg) == CHANGEOVER_PROTOCOL))
352 if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
354 if (likely(msg_user(bmsg) != MSG_BUNDLER))
356 if (likely(!TIPC_SKB_CB(bskb)->bundling))
358 if (unlikely(skb_tailroom(bskb) < (pad + msz)))
360 if (unlikely(max < (start + msz)))
363 skb_put(bskb, pad + msz);
364 skb_copy_to_linear_data_offset(bskb, start, skb->data, msz);
365 msg_set_size(bmsg, start + msz);
366 msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
372 * tipc_msg_extract(): extract bundled inner packet from buffer
373 * @skb: linear outer buffer, to be extracted from.
374 * @iskb: extracted inner buffer, to be returned
375 * @pos: position of msg to be extracted. Returns with pointer of next msg
376 * Consumes outer buffer when last packet extracted
377 * Returns true when when there is an extracted buffer, otherwise false
379 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
381 struct tipc_msg *msg = buf_msg(skb);
383 struct tipc_msg *imsg = (struct tipc_msg *)(msg_data(msg) + *pos);
385 /* Is there space left for shortest possible message? */
386 if (*pos > (msg_data_sz(msg) - SHORT_H_SIZE))
388 imsz = msg_size(imsg);
390 /* Is there space left for current message ? */
391 if ((*pos + imsz) > msg_data_sz(msg))
393 *iskb = tipc_buf_acquire(imsz);
396 skb_copy_to_linear_data(*iskb, imsg, imsz);
406 * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
407 * @list: the buffer chain
408 * @skb: buffer to be appended and replaced
409 * @mtu: max allowable size for the bundle buffer, inclusive header
410 * @dnode: destination node for message. (Not always present in header)
411 * Replaces buffer if successful
412 * Returns true if success, otherwise false
414 bool tipc_msg_make_bundle(struct sk_buff_head *list,
415 struct sk_buff *skb, u32 mtu, u32 dnode)
417 struct sk_buff *bskb;
418 struct tipc_msg *bmsg;
419 struct tipc_msg *msg = buf_msg(skb);
420 u32 msz = msg_size(msg);
421 u32 max = mtu - INT_H_SIZE;
423 if (msg_user(msg) == MSG_FRAGMENTER)
425 if (msg_user(msg) == CHANGEOVER_PROTOCOL)
427 if (msg_user(msg) == BCAST_PROTOCOL)
432 bskb = tipc_buf_acquire(max);
436 skb_trim(bskb, INT_H_SIZE);
437 bmsg = buf_msg(bskb);
438 tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
440 msg_set_seqno(bmsg, msg_seqno(msg));
441 msg_set_ack(bmsg, msg_ack(msg));
442 msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
443 TIPC_SKB_CB(bskb)->bundling = true;
444 __skb_queue_tail(list, bskb);
445 return tipc_msg_bundle(list, skb, mtu);
449 * tipc_msg_reverse(): swap source and destination addresses and add error code
450 * @buf: buffer containing message to be reversed
451 * @dnode: return value: node where to send message after reversal
452 * @err: error code to be set in message
453 * Consumes buffer if failure
454 * Returns true if success, otherwise false
456 bool tipc_msg_reverse(u32 own_addr, struct sk_buff *buf, u32 *dnode,
459 struct tipc_msg *msg = buf_msg(buf);
460 uint imp = msg_importance(msg);
461 struct tipc_msg ohdr;
462 uint rdsz = min_t(uint, msg_data_sz(msg), MAX_FORWARD_SIZE);
464 if (skb_linearize(buf))
466 if (msg_dest_droppable(msg))
468 if (msg_errcode(msg))
471 memcpy(&ohdr, msg, msg_hdr_sz(msg));
472 imp = min_t(uint, imp + 1, TIPC_CRITICAL_IMPORTANCE);
474 msg_set_importance(msg, imp);
475 msg_set_errcode(msg, err);
476 msg_set_origport(msg, msg_destport(&ohdr));
477 msg_set_destport(msg, msg_origport(&ohdr));
478 msg_set_prevnode(msg, own_addr);
479 if (!msg_short(msg)) {
480 msg_set_orignode(msg, msg_destnode(&ohdr));
481 msg_set_destnode(msg, msg_orignode(&ohdr));
483 msg_set_size(msg, msg_hdr_sz(msg) + rdsz);
484 skb_trim(buf, msg_size(msg));
486 *dnode = msg_orignode(&ohdr);
495 * tipc_msg_lookup_dest(): try to find new destination for named message
496 * @skb: the buffer containing the message.
497 * @dnode: return value: next-hop node, if destination found
498 * @err: return value: error code to use, if message to be rejected
499 * Does not consume buffer
500 * Returns true if a destination is found, false otherwise
502 bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb,
503 u32 *dnode, int *err)
505 struct tipc_msg *msg = buf_msg(skb);
508 if (!msg_isdata(msg))
512 *err = -TIPC_ERR_NO_NAME;
513 if (skb_linearize(skb))
515 if (msg_reroute_cnt(msg) > 0)
517 *dnode = addr_domain(net, msg_lookup_scope(msg));
518 dport = tipc_nametbl_translate(net, msg_nametype(msg),
519 msg_nameinst(msg), dnode);
522 msg_incr_reroute_cnt(msg);
523 msg_set_destnode(msg, *dnode);
524 msg_set_destport(msg, dport);
529 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
530 * reassemble the clones into one message
532 struct sk_buff *tipc_msg_reassemble(struct sk_buff_head *list)
535 struct sk_buff *frag = NULL;
536 struct sk_buff *head = NULL;
539 /* Copy header if single buffer */
540 if (skb_queue_len(list) == 1) {
541 skb = skb_peek(list);
542 hdr_sz = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
543 return __pskb_copy(skb, hdr_sz, GFP_ATOMIC);
546 /* Clone all fragments and reassemble */
547 skb_queue_walk(list, skb) {
548 frag = skb_clone(skb, GFP_ATOMIC);
552 if (tipc_buf_append(&head, &frag))
559 pr_warn("Failed do clone local mcast rcv buffer\n");