summaryrefslogtreecommitdiffstats
path: root/net/tipc/msg.c
blob: 18aba9e9934550318c8100a72c2c6dade4f0f088 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
/*
 * net/tipc/msg.c: TIPC message header routines
 *
 * Copyright (c) 2000-2006, 2014, Ericsson AB
 * Copyright (c) 2005, 2010-2011, Wind River Systems
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the names of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <net/sock.h>
#include "core.h"
#include "msg.h"
#include "addr.h"
#include "name_table.h"

#define MAX_FORWARD_SIZE 1024

static unsigned int align(unsigned int i)
{
	return (i + 3) & ~3u;
}

/**
 * tipc_buf_acquire - creates a TIPC message buffer
 * @size: message size (including TIPC header)
 *
 * Returns a new buffer with data pointers set to the specified size.
 *
 * NOTE: Headroom is reserved to allow prepending of a data link header.
 *       There may also be unrequested tailroom present at the buffer's end.
 */
struct sk_buff *tipc_buf_acquire(u32 size)
{
	struct sk_buff *skb;
	unsigned int buf_size = (BUF_HEADROOM + size + 3) & ~3u;

	skb = alloc_skb_fclone(buf_size, GFP_ATOMIC);
	if (skb) {
		skb_reserve(skb, BUF_HEADROOM);
		skb_put(skb, size);
		skb->next = NULL;
	}
	return skb;
}

void tipc_msg_init(struct net *net, struct tipc_msg *m, u32 user, u32 type,
		   u32 hsize, u32 destnode)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);

	memset(m, 0, hsize);
	msg_set_version(m);
	msg_set_user(m, user);
	msg_set_hdr_sz(m, hsize);
	msg_set_size(m, hsize);
	msg_set_prevnode(m, tn->own_addr);
	msg_set_type(m, type);
	if (hsize > SHORT_H_SIZE) {
		msg_set_orignode(m, tn->own_addr);
		msg_set_destnode(m, destnode);
	}
}

struct sk_buff *tipc_msg_create(struct net *net, uint user, uint type,
				uint hdr_sz, uint data_sz, u32 dnode,
				u32 onode, u32 dport, u32 oport, int errcode)
{
	struct tipc_msg *msg;
	struct sk_buff *buf;

	buf = tipc_buf_acquire(hdr_sz + data_sz);
	if (unlikely(!buf))
		return NULL;

	msg = buf_msg(buf);
	tipc_msg_init(net, msg, user, type, hdr_sz, dnode);
	msg_set_size(msg, hdr_sz + data_sz);
	msg_set_prevnode(msg, onode);
	msg_set_origport(msg, oport);
	msg_set_destport(msg, dport);
	msg_set_errcode(msg, errcode);
	if (hdr_sz > SHORT_H_SIZE) {
		msg_set_orignode(msg, onode);
		msg_set_destnode(msg, dnode);
	}
	return buf;
}

/* tipc_buf_append(): Append a buffer to the fragment list of another buffer
 * @*headbuf: in:  NULL for first frag, otherwise value returned from prev call
 *            out: set when successful non-complete reassembly, otherwise NULL
 * @*buf:     in:  the buffer to append. Always defined
 *            out: head buf after successful complete reassembly, otherwise NULL
 * Returns 1 when reassembly complete, otherwise 0
 */
int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
{
	struct sk_buff *head = *headbuf;
	struct sk_buff *frag = *buf;
	struct sk_buff *tail;
	struct tipc_msg *msg;
	u32 fragid;
	int delta;
	bool headstolen;

	if (!frag)
		goto err;

	msg = buf_msg(frag);
	fragid = msg_type(msg);
	frag->next = NULL;
	skb_pull(frag, msg_hdr_sz(msg));

	if (fragid == FIRST_FRAGMENT) {
		if (unlikely(head))
			goto err;
		if (unlikely(skb_unclone(frag, GFP_ATOMIC)))
			goto err;
		head = *headbuf = frag;
		skb_frag_list_init(head);
		TIPC_SKB_CB(head)->tail = NULL;
		*buf = NULL;
		return 0;
	}

	if (!head)
		goto err;

	if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
		kfree_skb_partial(frag, headstolen);
	} else {
		tail = TIPC_SKB_CB(head)->tail;
		if (!skb_has_frag_list(head))
			skb_shinfo(head)->frag_list = frag;
		else
			tail->next = frag;
		head->truesize += frag->truesize;
		head->data_len += frag->len;
		head->len += frag->len;
		TIPC_SKB_CB(head)->tail = frag;
	}

	if (fragid == LAST_FRAGMENT) {
		*buf = head;
		TIPC_SKB_CB(head)->tail = NULL;
		*headbuf = NULL;
		return 1;
	}
	*buf = NULL;
	return 0;

err:
	pr_warn_ratelimited("Unable to build fragment list\n");
	kfree_skb(*buf);
	kfree_skb(*headbuf);
	*buf = *headbuf = NULL;
	return 0;
}


/**
 * tipc_msg_build - create buffer chain containing specified header and data
 * @mhdr: Message header, to be prepended to data
 * @m: User message
 * @offset: Posision in iov to start copying from
 * @dsz: Total length of user data
 * @pktmax: Max packet size that can be used
 * @list: Buffer or chain of buffers to be returned to caller
 *
 * Returns message data size or errno: -ENOMEM, -EFAULT
 */
int tipc_msg_build(struct net *net, struct tipc_msg *mhdr, struct msghdr *m,
		   int offset, int dsz, int pktmax, struct sk_buff_head *list)
{
	int mhsz = msg_hdr_sz(mhdr);
	int msz = mhsz + dsz;
	int pktno = 1;
	int pktsz;
	int pktrem = pktmax;
	int drem = dsz;
	struct tipc_msg pkthdr;
	struct sk_buff *skb;
	char *pktpos;
	int rc;

	msg_set_size(mhdr, msz);

	/* No fragmentation needed? */
	if (likely(msz <= pktmax)) {
		skb = tipc_buf_acquire(msz);
		if (unlikely(!skb))
			return -ENOMEM;
		skb_orphan(skb);
		__skb_queue_tail(list, skb);
		skb_copy_to_linear_data(skb, mhdr, mhsz);
		pktpos = skb->data + mhsz;
		if (!dsz || !memcpy_fromiovecend(pktpos, m->msg_iter.iov, offset,
						 dsz))
			return dsz;
		rc = -EFAULT;
		goto error;
	}

	/* Prepare reusable fragment header */
	tipc_msg_init(net, &pkthdr, MSG_FRAGMENTER, FIRST_FRAGMENT, INT_H_SIZE,
		      msg_destnode(mhdr));
	msg_set_size(&pkthdr, pktmax);
	msg_set_fragm_no(&pkthdr, pktno);

	/* Prepare first fragment */
	skb = tipc_buf_acquire(pktmax);
	if (!skb)
		return -ENOMEM;
	skb_orphan(skb);
	__skb_queue_tail(list, skb);
	pktpos = skb->data;
	skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
	pktpos += INT_H_SIZE;
	pktrem -= INT_H_SIZE;
	skb_copy_to_linear_data_offset(skb, INT_H_SIZE, mhdr, mhsz);
	pktpos += mhsz;
	pktrem -= mhsz;

	do {
		if (drem < pktrem)
			pktrem = drem;

		if (memcpy_fromiovecend(pktpos, m->msg_iter.iov, offset, pktrem)) {
			rc = -EFAULT;
			goto error;
		}
		drem -= pktrem;
		offset += pktrem;

		if (!drem)
			break;

		/* Prepare new fragment: */
		if (drem < (pktmax - INT_H_SIZE))
			pktsz = drem + INT_H_SIZE;
		else
			pktsz = pktmax;
		skb = tipc_buf_acquire(pktsz);
		if (!skb) {
			rc = -ENOMEM;
			goto error;
		}
		skb_orphan(skb);
		__skb_queue_tail(list, skb);
		msg_set_type(&pkthdr, FRAGMENT);
		msg_set_size(&pkthdr, pktsz);
		msg_set_fragm_no(&pkthdr, ++pktno);
		skb_copy_to_linear_data(skb, &pkthdr, INT_H_SIZE);
		pktpos = skb->data + INT_H_SIZE;
		pktrem = pktsz - INT_H_SIZE;

	} while (1);
	msg_set_type(buf_msg(skb), LAST_FRAGMENT);
	return dsz;
error:
	__skb_queue_purge(list);
	__skb_queue_head_init(list);
	return rc;
}

/**
 * tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
 * @list: the buffer chain of the existing buffer ("bundle")
 * @skb:  buffer to be appended
 * @mtu:  max allowable size for the bundle buffer
 * Consumes buffer if successful
 * Returns true if bundling could be performed, otherwise false
 */
bool tipc_msg_bundle(struct sk_buff_head *list, struct sk_buff *skb, u32 mtu)
{
	struct sk_buff *bskb = skb_peek_tail(list);
	struct tipc_msg *bmsg = buf_msg(bskb);
	struct tipc_msg *msg = buf_msg(skb);
	unsigned int bsz = msg_size(bmsg);
	unsigned int msz = msg_size(msg);
	u32 start = align(bsz);
	u32 max = mtu - INT_H_SIZE;
	u32 pad = start - bsz;

	if (likely(msg_user(msg) == MSG_FRAGMENTER))
		return false;
	if (unlikely(msg_user(msg) == CHANGEOVER_PROTOCOL))
		return false;
	if (unlikely(msg_user(msg) == BCAST_PROTOCOL))
		return false;
	if (likely(msg_user(bmsg) != MSG_BUNDLER))
		return false;
	if (likely(!TIPC_SKB_CB(bskb)->bundling))
		return false;
	if (unlikely(skb_tailroom(bskb) < (pad + msz)))
		return false;
	if (unlikely(max < (start + msz)))
		return false;

	skb_put(bskb, pad + msz);
	skb_copy_to_linear_data_offset(bskb, start, skb->data, msz);
	msg_set_size(bmsg, start + msz);
	msg_set_msgcnt(bmsg, msg_msgcnt(bmsg) + 1);
	kfree_skb(skb);
	return true;
}

/**
 * tipc_msg_make_bundle(): Create bundle buf and append message to its tail
 * @list: the buffer chain
 * @skb: buffer to be appended and replaced
 * @mtu: max allowable size for the bundle buffer, inclusive header
 * @dnode: destination node for message. (Not always present in header)
 * Replaces buffer if successful
 * Returns true if success, otherwise false
 */
bool tipc_msg_make_bundle(struct net *net, struct sk_buff_head *list,
			  struct sk_buff *skb, u32 mtu, u32 dnode)
{
	struct sk_buff *bskb;
	struct tipc_msg *bmsg;
	struct tipc_msg *msg = buf_msg(skb);
	u32 msz = msg_size(msg);
	u32 max = mtu - INT_H_SIZE;

	if (msg_user(msg) == MSG_FRAGMENTER)
		return false;
	if (msg_user(msg) == CHANGEOVER_PROTOCOL)
		return false;
	if (msg_user(msg) == BCAST_PROTOCOL)
		return false;
	if (msz > (max / 2))
		return false;

	bskb = tipc_buf_acquire(max);
	if (!bskb)
		return false;

	skb_trim(bskb, INT_H_SIZE);
	bmsg = buf_msg(bskb);
	tipc_msg_init(net, bmsg, MSG_BUNDLER, 0, INT_H_SIZE, dnode);
	msg_set_seqno(bmsg, msg_seqno(msg));
	msg_set_ack(bmsg, msg_ack(msg));
	msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
	TIPC_SKB_CB(bskb)->bundling = true;
	__skb_queue_tail(list, bskb);
	return tipc_msg_bundle(list, skb, mtu);
}

/**
 * tipc_msg_reverse(): swap source and destination addresses and add error code
 * @buf:  buffer containing message to be reversed
 * @dnode: return value: node where to send message after reversal
 * @err:  error code to be set in message
 * Consumes buffer if failure
 * Returns true if success, otherwise false
 */
bool tipc_msg_reverse(struct net *net, struct sk_buff *buf, u32 *dnode,
		      int err)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_msg *msg = buf_msg(buf);
	uint imp = msg_importance(msg);
	struct tipc_msg ohdr;
	uint rdsz = min_t(uint, msg_data_sz(msg), MAX_FORWARD_SIZE);

	if (skb_linearize(buf))
		goto exit;
	if (msg_dest_droppable(msg))
		goto exit;
	if (msg_errcode(msg))
		goto exit;

	memcpy(&ohdr, msg, msg_hdr_sz(msg));
	imp = min_t(uint, imp + 1, TIPC_CRITICAL_IMPORTANCE);
	if (msg_isdata(msg))
		msg_set_importance(msg, imp);
	msg_set_errcode(msg, err);
	msg_set_origport(msg, msg_destport(&ohdr));
	msg_set_destport(msg, msg_origport(&ohdr));
	msg_set_prevnode(msg, tn->own_addr);
	if (!msg_short(msg)) {
		msg_set_orignode(msg, msg_destnode(&ohdr));
		msg_set_destnode(msg, msg_orignode(&ohdr));
	}
	msg_set_size(msg, msg_hdr_sz(msg) + rdsz);
	skb_trim(buf, msg_size(msg));
	skb_orphan(buf);
	*dnode = msg_orignode(&ohdr);
	return true;
exit:
	kfree_skb(buf);
	return false;
}

/**
 * tipc_msg_eval: determine fate of message that found no destination
 * @buf: the buffer containing the message.
 * @dnode: return value: next-hop node, if message to be forwarded
 * @err: error code to use, if message to be rejected
 *
 * Does not consume buffer
 * Returns 0 (TIPC_OK) if message ok and we can try again, -TIPC error
 * code if message to be rejected
 */
int tipc_msg_eval(struct net *net, struct sk_buff *buf, u32 *dnode)
{
	struct tipc_msg *msg = buf_msg(buf);
	u32 dport;

	if (msg_type(msg) != TIPC_NAMED_MSG)
		return -TIPC_ERR_NO_PORT;
	if (skb_linearize(buf))
		return -TIPC_ERR_NO_NAME;
	if (msg_data_sz(msg) > MAX_FORWARD_SIZE)
		return -TIPC_ERR_NO_NAME;
	if (msg_reroute_cnt(msg) > 0)
		return -TIPC_ERR_NO_NAME;

	*dnode = addr_domain(net, msg_lookup_scope(msg));
	dport = tipc_nametbl_translate(net, msg_nametype(msg),
				       msg_nameinst(msg),
				       dnode);
	if (!dport)
		return -TIPC_ERR_NO_NAME;
	msg_incr_reroute_cnt(msg);
	msg_set_destnode(msg, *dnode);
	msg_set_destport(msg, dport);
	return TIPC_OK;
}

/* tipc_msg_reassemble() - clone a buffer chain of fragments and
 *                         reassemble the clones into one message
 */
struct sk_buff *tipc_msg_reassemble(struct sk_buff_head *list)
{
	struct sk_buff *skb;
	struct sk_buff *frag = NULL;
	struct sk_buff *head = NULL;
	int hdr_sz;

	/* Copy header if single buffer */
	if (skb_queue_len(list) == 1) {
		skb = skb_peek(list);
		hdr_sz = skb_headroom(skb) + msg_hdr_sz(buf_msg(skb));
		return __pskb_copy(skb, hdr_sz, GFP_ATOMIC);
	}

	/* Clone all fragments and reassemble */
	skb_queue_walk(list, skb) {
		frag = skb_clone(skb, GFP_ATOMIC);
		if (!frag)
			goto error;
		frag->next = NULL;
		if (tipc_buf_append(&head, &frag))
			break;
		if (!head)
			goto error;
	}
	return frag;
error:
	pr_warn("Failed do clone local mcast rcv buffer\n");
	kfree_skb(head);
	return NULL;
}