2 * net/tipc/msg.c: TIPC message header routines
4 * Copyright (c) 2000-2006, 2014, Ericsson AB
5 * Copyright (c) 2005, 2010-2011, Wind River Systems
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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(struct net *net, struct tipc_msg *m, u32 user, u32 type,
74 u32 hsize, u32 destnode)
76 struct tipc_net *tn = net_generic(net, tipc_net_id);
80 msg_set_user(m, user);
81 msg_set_hdr_sz(m, hsize);
82 msg_set_size(m, hsize);
83 msg_set_prevnode(m, tn->own_addr);
84 msg_set_type(m, type);
85 if (hsize > SHORT_H_SIZE) {
86 msg_set_orignode(m, tn->own_addr);
87 msg_set_destnode(m, destnode);
91 struct sk_buff *tipc_msg_create(struct net *net, 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);
103 tipc_msg_init(net, msg, user, type, hdr_sz, dnode);
104 msg_set_size(msg, hdr_sz + data_sz);
105 msg_set_prevnode(msg, onode);
106 msg_set_origport(msg, oport);
107 msg_set_destport(msg, dport);
108 msg_set_errcode(msg, errcode);
109 if (hdr_sz > SHORT_H_SIZE) {
110 msg_set_orignode(msg, onode);
111 msg_set_destnode(msg, dnode);
116 /* tipc_buf_append(): Append a buffer to the fragment list of another buffer
117 * @*headbuf: in: NULL for first frag, otherwise value returned from prev call
118 * out: set when successful non-complete reassembly, otherwise NULL
119 * @*buf: in: the buffer to append. Always defined
120 * out: head buf after successful complete reassembly, otherwise NULL
121 * Returns 1 when reassembly complete, otherwise 0
123 int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
125 struct sk_buff *head = *headbuf;
126 struct sk_buff *frag = *buf;
127 struct sk_buff *tail;
128 struct tipc_msg *msg;
137 fragid = msg_type(msg);
139 skb_pull(frag, msg_hdr_sz(msg));
141 if (fragid == FIRST_FRAGMENT) {
144 if (unlikely(skb_unclone(frag, GFP_ATOMIC)))
146 head = *headbuf = frag;
147 skb_frag_list_init(head);
148 TIPC_SKB_CB(head)->tail = NULL;
156 if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
157 kfree_skb_partial(frag, headstolen);
159 tail = TIPC_SKB_CB(head)->tail;
160 if (!skb_has_frag_list(head))
161 skb_shinfo(head)->frag_list = frag;
164 head->truesize += frag->truesize;
165 head->data_len += frag->len;
166 head->len += frag->len;
167 TIPC_SKB_CB(head)->tail = frag;
170 if (fragid == LAST_FRAGMENT) {
172 TIPC_SKB_CB(head)->tail = NULL;
180 pr_warn_ratelimited("Unable to build fragment list\n");
183 *buf = *headbuf = NULL;
189 * tipc_msg_build - create buffer chain containing specified header and data
190 * @mhdr: Message header, to be prepended to data
192 * @offset: Posision in iov to start copying from
193 * @dsz: Total length of user data
194 * @pktmax: Max packet size that can be used
195 * @list: Buffer or chain of buffers to be returned to caller
197 * Returns message data size or errno: -ENOMEM, -EFAULT
199 int tipc_msg_build(struct net *net, struct tipc_msg *mhdr, struct msghdr *m,
200 int offset, int dsz, int pktmax, struct sk_buff_head *list)
202 int mhsz = msg_hdr_sz(mhdr);
203 int msz = mhsz + dsz;
208 struct tipc_msg pkthdr;
213 msg_set_size(mhdr, msz);
215 /* No fragmentation needed? */
216 if (likely(msz <= pktmax)) {
217 skb = tipc_buf_acquire(msz);
221 __skb_queue_tail(list, skb);
222 skb_copy_to_linear_data(skb, mhdr, mhsz);
223 pktpos = skb->data + mhsz;
224 if (!dsz || !memcpy_fromiovecend(pktpos, m->msg_iter.iov, offset,
231 /* Prepare reusable fragment header */
232 tipc_msg_init(net, &pkthdr, MSG_FRAGMENTER, FIRST_FRAGMENT, INT_H_SIZE,
234 msg_set_size(&pkthdr, pktmax);
235 msg_set_fragm_no(&pkthdr, pktno);
237 /* Prepare first fragment */
238 skb = tipc_buf_acquire(pktmax);
242 __skb_queue_tail(list, skb);
244 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
245 pktpos += INT_H_SIZE;
246 pktrem -= INT_H_SIZE;
247 skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
255 if (memcpy_fromiovecend(pktpos, m->msg_iter.iov, offset, pktrem)) {
265 /* Prepare new fragment: */
266 if (drem < (pktmax - INT_H_SIZE))
267 pktsz = drem + INT_H_SIZE;
270 skb = tipc_buf_acquire(pktsz);
276 __skb_queue_tail(list, skb);
277 msg_set_type(&pkthdr, FRAGMENT);
278 msg_set_size(&pkthdr, pktsz);
279 msg_set_fragm_no(&pkthdr, ++pktno);
280 skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
281 pktpos = skb->data + INT_H_SIZE;
282 pktrem = pktsz - INT_H_SIZE;
285 msg_set_type(buf_msg(skb), LAST_FRAGMENT);
288 __skb_queue_purge(list);
289 __skb_queue_head_init(list);
294 * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
295 * @list: the buffer chain of the existing buffer ("bundle")
296 * @skb: buffer to be appended
297 * @mtu: max allowable size for the bundle buffer
298 * Consumes buffer if successful
299 * Returns true if bundling could be performed, otherwise false
301 bool tipc_msg_bundle(struct sk_buff_head *list, struct sk_buff *skb, u32 mtu)
303 struct sk_buff *bskb = skb_peek_tail(list);
304 struct tipc_msg *bmsg = buf_msg(bskb);
305 struct tipc_msg *msg = buf_msg(skb);
306 unsigned int bsz = msg_size(bmsg);
307 unsigned int msz = msg_size(msg);
308 u32 start = align(bsz);
309 u32 max = mtu - INT_H_SIZE;
310 u32 pad = start - bsz;
312 if (likely(msg_user(msg) == MSG_FRAGMENTER))
314 if (unlikely(msg_user(msg) == CHANGEOVER_PROTOCOL))
316 if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
318 if (likely(msg_user(bmsg) != MSG_BUNDLER))
320 if (likely(!TIPC_SKB_CB(bskb)->bundling))
322 if (unlikely(skb_tailroom(bskb) < (pad + msz)))
324 if (unlikely(max < (start + msz)))
327 skb_put(bskb, pad + msz);
328 skb_copy_to_linear_data_offset(bskb, start, skb->data, msz);
329 msg_set_size(bmsg, start + msz);
330 msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
336 * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
337 * @list: the buffer chain
338 * @skb: buffer to be appended and replaced
339 * @mtu: max allowable size for the bundle buffer, inclusive header
340 * @dnode: destination node for message. (Not always present in header)
341 * Replaces buffer if successful
342 * Returns true if success, otherwise false
344 bool tipc_msg_make_bundle(struct net *net, struct sk_buff_head *list,
345 struct sk_buff *skb, u32 mtu, u32 dnode)
347 struct sk_buff *bskb;
348 struct tipc_msg *bmsg;
349 struct tipc_msg *msg = buf_msg(skb);
350 u32 msz = msg_size(msg);
351 u32 max = mtu - INT_H_SIZE;
353 if (msg_user(msg) == MSG_FRAGMENTER)
355 if (msg_user(msg) == CHANGEOVER_PROTOCOL)
357 if (msg_user(msg) == BCAST_PROTOCOL)
362 bskb = tipc_buf_acquire(max);
366 skb_trim(bskb, INT_H_SIZE);
367 bmsg = buf_msg(bskb);
368 tipc_msg_init(net, bmsg, MSG_BUNDLER, 0, INT_H_SIZE, dnode);
369 msg_set_seqno(bmsg, msg_seqno(msg));
370 msg_set_ack(bmsg, msg_ack(msg));
371 msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
372 TIPC_SKB_CB(bskb)->bundling = true;
373 __skb_queue_tail(list, bskb);
374 return tipc_msg_bundle(list, skb, mtu);
378 * tipc_msg_reverse(): swap source and destination addresses and add error code
379 * @buf: buffer containing message to be reversed
380 * @dnode: return value: node where to send message after reversal
381 * @err: error code to be set in message
382 * Consumes buffer if failure
383 * Returns true if success, otherwise false
385 bool tipc_msg_reverse(struct net *net, struct sk_buff *buf, u32 *dnode,
388 struct tipc_net *tn = net_generic(net, tipc_net_id);
389 struct tipc_msg *msg = buf_msg(buf);
390 uint imp = msg_importance(msg);
391 struct tipc_msg ohdr;
392 uint rdsz = min_t(uint, msg_data_sz(msg), MAX_FORWARD_SIZE);
394 if (skb_linearize(buf))
396 if (msg_dest_droppable(msg))
398 if (msg_errcode(msg))
401 memcpy(&ohdr, msg, msg_hdr_sz(msg));
402 imp = min_t(uint, imp + 1, TIPC_CRITICAL_IMPORTANCE);
404 msg_set_importance(msg, imp);
405 msg_set_errcode(msg, err);
406 msg_set_origport(msg, msg_destport(&ohdr));
407 msg_set_destport(msg, msg_origport(&ohdr));
408 msg_set_prevnode(msg, tn->own_addr);
409 if (!msg_short(msg)) {
410 msg_set_orignode(msg, msg_destnode(&ohdr));
411 msg_set_destnode(msg, msg_orignode(&ohdr));
413 msg_set_size(msg, msg_hdr_sz(msg) + rdsz);
414 skb_trim(buf, msg_size(msg));
416 *dnode = msg_orignode(&ohdr);
424 * tipc_msg_eval: determine fate of message that found no destination
425 * @buf: the buffer containing the message.
426 * @dnode: return value: next-hop node, if message to be forwarded
427 * @err: error code to use, if message to be rejected
429 * Does not consume buffer
430 * Returns 0 (TIPC_OK) if message ok and we can try again, -TIPC error
431 * code if message to be rejected
433 int tipc_msg_eval(struct net *net, struct sk_buff *buf, u32 *dnode)
435 struct tipc_msg *msg = buf_msg(buf);
438 if (msg_type(msg) != TIPC_NAMED_MSG)
439 return -TIPC_ERR_NO_PORT;
440 if (skb_linearize(buf))
441 return -TIPC_ERR_NO_NAME;
442 if (msg_data_sz(msg) > MAX_FORWARD_SIZE)
443 return -TIPC_ERR_NO_NAME;
444 if (msg_reroute_cnt(msg) > 0)
445 return -TIPC_ERR_NO_NAME;
447 *dnode = addr_domain(net, msg_lookup_scope(msg));
448 dport = tipc_nametbl_translate(net, msg_nametype(msg),
452 return -TIPC_ERR_NO_NAME;
453 msg_incr_reroute_cnt(msg);
454 msg_set_destnode(msg, *dnode);
455 msg_set_destport(msg, dport);
459 /* tipc_msg_reassemble() - clone a buffer chain of fragments and
460 * reassemble the clones into one message
462 struct sk_buff *tipc_msg_reassemble(struct sk_buff_head *list)
465 struct sk_buff *frag = NULL;
466 struct sk_buff *head = NULL;
469 /* Copy header if single buffer */
470 if (skb_queue_len(list) == 1) {
471 skb = skb_peek(list);
472 hdr_sz = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
473 return __pskb_copy(skb, hdr_sz, GFP_ATOMIC);
476 /* Clone all fragments and reassemble */
477 skb_queue_walk(list, skb) {
478 frag = skb_clone(skb, GFP_ATOMIC);
482 if (tipc_buf_append(&head, &frag))
489 pr_warn("Failed do clone local mcast rcv buffer\n");