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);
276 /* Prepare first fragment */
277 skb = tipc_buf_acquire(pktmax);
281 __skb_queue_tail(list, skb);
283 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
284 pktpos += INT_H_SIZE;
285 pktrem -= INT_H_SIZE;
286 skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
294 if (copy_from_iter(pktpos, pktrem, &m->msg_iter) != pktrem) {
303 /* Prepare new fragment: */
304 if (drem < (pktmax - INT_H_SIZE))
305 pktsz = drem + INT_H_SIZE;
308 skb = tipc_buf_acquire(pktsz);
314 __skb_queue_tail(list, skb);
315 msg_set_type(&pkthdr, FRAGMENT);
316 msg_set_size(&pkthdr, pktsz);
317 msg_set_fragm_no(&pkthdr, ++pktno);
318 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
319 pktpos = skb->data + INT_H_SIZE;
320 pktrem = pktsz - INT_H_SIZE;
323 msg_set_type(buf_msg(skb), LAST_FRAGMENT);
326 __skb_queue_purge(list);
327 __skb_queue_head_init(list);
332 * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
333 * @list: the buffer chain of the existing buffer ("bundle")
334 * @skb: buffer to be appended
335 * @mtu: max allowable size for the bundle buffer
336 * Consumes buffer if successful
337 * Returns true if bundling could be performed, otherwise false
339 bool tipc_msg_bundle(struct sk_buff_head *list, struct sk_buff *skb, u32 mtu)
341 struct sk_buff *bskb = skb_peek_tail(list);
342 struct tipc_msg *bmsg = buf_msg(bskb);
343 struct tipc_msg *msg = buf_msg(skb);
344 unsigned int bsz = msg_size(bmsg);
345 unsigned int msz = msg_size(msg);
346 u32 start = align(bsz);
347 u32 max = mtu - INT_H_SIZE;
348 u32 pad = start - bsz;
350 if (likely(msg_user(msg) == MSG_FRAGMENTER))
352 if (unlikely(msg_user(msg) == CHANGEOVER_PROTOCOL))
354 if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
356 if (likely(msg_user(bmsg) != MSG_BUNDLER))
358 if (likely(!TIPC_SKB_CB(bskb)->bundling))
360 if (unlikely(skb_tailroom(bskb) < (pad + msz)))
362 if (unlikely(max < (start + msz)))
365 skb_put(bskb, pad + msz);
366 skb_copy_to_linear_data_offset(bskb, start, skb->data, msz);
367 msg_set_size(bmsg, start + msz);
368 msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
374 * tipc_msg_extract(): extract bundled inner packet from buffer
375 * @skb: linear outer buffer, to be extracted from.
376 * @iskb: extracted inner buffer, to be returned
377 * @pos: position of msg to be extracted. Returns with pointer of next msg
378 * Consumes outer buffer when last packet extracted
379 * Returns true when when there is an extracted buffer, otherwise false
381 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
383 struct tipc_msg *msg;
385 struct tipc_msg *imsg;
387 if (unlikely(skb_linearize(skb)))
390 imsg = (struct tipc_msg *)(msg_data(msg) + *pos);
391 /* Is there space left for shortest possible message? */
392 if (*pos > (msg_data_sz(msg) - SHORT_H_SIZE))
394 imsz = msg_size(imsg);
396 /* Is there space left for current message ? */
397 if ((*pos + imsz) > msg_data_sz(msg))
399 *iskb = tipc_buf_acquire(imsz);
402 skb_copy_to_linear_data(*iskb, imsg, imsz);
412 * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
413 * @list: the buffer chain
414 * @skb: buffer to be appended and replaced
415 * @mtu: max allowable size for the bundle buffer, inclusive header
416 * @dnode: destination node for message. (Not always present in header)
417 * Replaces buffer if successful
418 * Returns true if success, otherwise false
420 bool tipc_msg_make_bundle(struct sk_buff_head *list,
421 struct sk_buff *skb, u32 mtu, u32 dnode)
423 struct sk_buff *bskb;
424 struct tipc_msg *bmsg;
425 struct tipc_msg *msg = buf_msg(skb);
426 u32 msz = msg_size(msg);
427 u32 max = mtu - INT_H_SIZE;
429 if (msg_user(msg) == MSG_FRAGMENTER)
431 if (msg_user(msg) == CHANGEOVER_PROTOCOL)
433 if (msg_user(msg) == BCAST_PROTOCOL)
438 bskb = tipc_buf_acquire(max);
442 skb_trim(bskb, INT_H_SIZE);
443 bmsg = buf_msg(bskb);
444 tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
446 msg_set_seqno(bmsg, msg_seqno(msg));
447 msg_set_ack(bmsg, msg_ack(msg));
448 msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
449 TIPC_SKB_CB(bskb)->bundling = true;
450 __skb_queue_tail(list, bskb);
451 return tipc_msg_bundle(list, skb, mtu);
455 * tipc_msg_reverse(): swap source and destination addresses and add error code
456 * @buf: buffer containing message to be reversed
457 * @dnode: return value: node where to send message after reversal
458 * @err: error code to be set in message
459 * Consumes buffer if failure
460 * Returns true if success, otherwise false
462 bool tipc_msg_reverse(u32 own_addr, struct sk_buff *buf, u32 *dnode,
465 struct tipc_msg *msg = buf_msg(buf);
466 uint imp = msg_importance(msg);
467 struct tipc_msg ohdr;
468 uint rdsz = min_t(uint, msg_data_sz(msg), MAX_FORWARD_SIZE);
470 if (skb_linearize(buf))
473 if (msg_dest_droppable(msg))
475 if (msg_errcode(msg))
477 memcpy(&ohdr, msg, msg_hdr_sz(msg));
478 imp = min_t(uint, imp + 1, TIPC_CRITICAL_IMPORTANCE);
480 msg_set_importance(msg, imp);
481 msg_set_errcode(msg, err);
482 msg_set_origport(msg, msg_destport(&ohdr));
483 msg_set_destport(msg, msg_origport(&ohdr));
484 msg_set_prevnode(msg, own_addr);
485 if (!msg_short(msg)) {
486 msg_set_orignode(msg, msg_destnode(&ohdr));
487 msg_set_destnode(msg, msg_orignode(&ohdr));
489 msg_set_size(msg, msg_hdr_sz(msg) + rdsz);
490 skb_trim(buf, msg_size(msg));
492 *dnode = msg_orignode(&ohdr);
501 * tipc_msg_lookup_dest(): try to find new destination for named message
502 * @skb: the buffer containing the message.
503 * @dnode: return value: next-hop node, if destination found
504 * @err: return value: error code to use, if message to be rejected
505 * Does not consume buffer
506 * Returns true if a destination is found, false otherwise
508 bool tipc_msg_lookup_dest(struct net *net, struct sk_buff *skb,
509 u32 *dnode, int *err)
511 struct tipc_msg *msg = buf_msg(skb);
514 if (!msg_isdata(msg))
518 *err = -TIPC_ERR_NO_NAME;
519 if (skb_linearize(skb))
521 if (msg_reroute_cnt(msg) > 0)
523 *dnode = addr_domain(net, msg_lookup_scope(msg));
524 dport = tipc_nametbl_translate(net, msg_nametype(msg),
525 msg_nameinst(msg), dnode);
528 msg_incr_reroute_cnt(msg);
529 msg_set_destnode(msg, *dnode);
530 msg_set_destport(msg, dport);
535 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
536 * reassemble the clones into one message
538 struct sk_buff *tipc_msg_reassemble(struct sk_buff_head *list)
541 struct sk_buff *frag = NULL;
542 struct sk_buff *head = NULL;
545 /* Copy header if single buffer */
546 if (skb_queue_len(list) == 1) {
547 skb = skb_peek(list);
548 hdr_sz = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
549 return __pskb_copy(skb, hdr_sz, GFP_ATOMIC);
552 /* Clone all fragments and reassemble */
553 skb_queue_walk(list, skb) {
554 frag = skb_clone(skb, GFP_ATOMIC);
558 if (tipc_buf_append(&head, &frag))
565 pr_warn("Failed do clone local mcast rcv buffer\n");