summaryrefslogtreecommitdiffstats
path: root/net/batman-adv/unicast.c
blob: dc8b5d4dd636d3d5ed982a5d93c2783f203ac4f5 (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
/* Copyright (C) 2010-2013 B.A.T.M.A.N. contributors:
 *
 * Andreas Langer
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA
 */

#include "main.h"
#include "unicast.h"
#include "send.h"
#include "soft-interface.h"
#include "gateway_client.h"
#include "originator.h"
#include "hash.h"
#include "translation-table.h"
#include "routing.h"
#include "hard-interface.h"


static struct sk_buff *
batadv_frag_merge_packet(struct list_head *head,
			 struct batadv_frag_packet_list_entry *tfp,
			 struct sk_buff *skb)
{
	struct batadv_unicast_frag_packet *up;
	struct sk_buff *tmp_skb;
	struct batadv_unicast_packet *unicast_packet;
	int hdr_len = sizeof(*unicast_packet);
	int uni_diff = sizeof(*up) - hdr_len;
	uint8_t *packet_pos;

	up = (struct batadv_unicast_frag_packet *)skb->data;
	/* set skb to the first part and tmp_skb to the second part */
	if (up->flags & BATADV_UNI_FRAG_HEAD) {
		tmp_skb = tfp->skb;
	} else {
		tmp_skb = skb;
		skb = tfp->skb;
	}

	if (skb_linearize(skb) < 0 || skb_linearize(tmp_skb) < 0)
		goto err;

	skb_pull(tmp_skb, sizeof(*up));
	if (pskb_expand_head(skb, 0, tmp_skb->len, GFP_ATOMIC) < 0)
		goto err;

	/* move free entry to end */
	tfp->skb = NULL;
	tfp->seqno = 0;
	list_move_tail(&tfp->list, head);

	memcpy(skb_put(skb, tmp_skb->len), tmp_skb->data, tmp_skb->len);
	kfree_skb(tmp_skb);

	memmove(skb->data + uni_diff, skb->data, hdr_len);
	packet_pos = skb_pull(skb, uni_diff);
	unicast_packet = (struct batadv_unicast_packet *)packet_pos;
	unicast_packet->header.packet_type = BATADV_UNICAST;

	return skb;

err:
	/* free buffered skb, skb will be freed later */
	kfree_skb(tfp->skb);
	return NULL;
}

static void batadv_frag_create_entry(struct list_head *head,
				     struct sk_buff *skb)
{
	struct batadv_frag_packet_list_entry *tfp;
	struct batadv_unicast_frag_packet *up;

	up = (struct batadv_unicast_frag_packet *)skb->data;

	/* free and oldest packets stand at the end */
	tfp = list_entry((head)->prev, typeof(*tfp), list);
	kfree_skb(tfp->skb);

	tfp->seqno = ntohs(up->seqno);
	tfp->skb = skb;
	list_move(&tfp->list, head);
	return;
}

static int batadv_frag_create_buffer(struct list_head *head)
{
	int i;
	struct batadv_frag_packet_list_entry *tfp;

	for (i = 0; i < BATADV_FRAG_BUFFER_SIZE; i++) {
		tfp = kmalloc(sizeof(*tfp), GFP_ATOMIC);
		if (!tfp) {
			batadv_frag_list_free(head);
			return -ENOMEM;
		}
		tfp->skb = NULL;
		tfp->seqno = 0;
		INIT_LIST_HEAD(&tfp->list);
		list_add(&tfp->list, head);
	}

	return 0;
}

static struct batadv_frag_packet_list_entry *
batadv_frag_search_packet(struct list_head *head,
			  const struct batadv_unicast_frag_packet *up)
{
	struct batadv_frag_packet_list_entry *tfp;
	struct batadv_unicast_frag_packet *tmp_up = NULL;
	bool is_head_tmp, is_head;
	uint16_t search_seqno;

	if (up->flags & BATADV_UNI_FRAG_HEAD)
		search_seqno = ntohs(up->seqno)+1;
	else
		search_seqno = ntohs(up->seqno)-1;

	is_head = up->flags & BATADV_UNI_FRAG_HEAD;

	list_for_each_entry(tfp, head, list) {
		if (!tfp->skb)
			continue;

		if (tfp->seqno == ntohs(up->seqno))
			goto mov_tail;

		tmp_up = (struct batadv_unicast_frag_packet *)tfp->skb->data;

		if (tfp->seqno == search_seqno) {
			is_head_tmp = tmp_up->flags & BATADV_UNI_FRAG_HEAD;
			if (is_head_tmp != is_head)
				return tfp;
			else
				goto mov_tail;
		}
	}
	return NULL;

mov_tail:
	list_move_tail(&tfp->list, head);
	return NULL;
}

void batadv_frag_list_free(struct list_head *head)
{
	struct batadv_frag_packet_list_entry *pf, *tmp_pf;

	if (!list_empty(head)) {
		list_for_each_entry_safe(pf, tmp_pf, head, list) {
			kfree_skb(pf->skb);
			list_del(&pf->list);
			kfree(pf);
		}
	}
	return;
}

/* frag_reassemble_skb():
 * returns NET_RX_DROP if the operation failed - skb is left intact
 * returns NET_RX_SUCCESS if the fragment was buffered (skb_new will be NULL)
 * or the skb could be reassembled (skb_new will point to the new packet and
 * skb was freed)
 */
int batadv_frag_reassemble_skb(struct sk_buff *skb,
			       struct batadv_priv *bat_priv,
			       struct sk_buff **new_skb)
{
	struct batadv_orig_node *orig_node;
	struct batadv_frag_packet_list_entry *tmp_frag_entry;
	int ret = NET_RX_DROP;
	struct batadv_unicast_frag_packet *unicast_packet;

	unicast_packet = (struct batadv_unicast_frag_packet *)skb->data;
	*new_skb = NULL;

	orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->orig);
	if (!orig_node)
		goto out;

	orig_node->last_frag_packet = jiffies;

	if (list_empty(&orig_node->frag_list) &&
	    batadv_frag_create_buffer(&orig_node->frag_list)) {
		pr_debug("couldn't create frag buffer\n");
		goto out;
	}

	tmp_frag_entry = batadv_frag_search_packet(&orig_node->frag_list,
						   unicast_packet);

	if (!tmp_frag_entry) {
		batadv_frag_create_entry(&orig_node->frag_list, skb);
		ret = NET_RX_SUCCESS;
		goto out;
	}

	*new_skb = batadv_frag_merge_packet(&orig_node->frag_list,
					    tmp_frag_entry, skb);
	/* if not, merge failed */
	if (*new_skb)
		ret = NET_RX_SUCCESS;

out:
	if (orig_node)
		batadv_orig_node_free_ref(orig_node);
	return ret;
}

int batadv_frag_send_skb(struct sk_buff *skb, struct batadv_priv *bat_priv,
			 struct batadv_hard_iface *hard_iface,
			 const uint8_t dstaddr[])
{
	struct batadv_unicast_packet tmp_uc, *unicast_packet;
	struct batadv_hard_iface *primary_if;
	struct sk_buff *frag_skb;
	struct batadv_unicast_frag_packet *frag1, *frag2;
	int uc_hdr_len = sizeof(*unicast_packet);
	int ucf_hdr_len = sizeof(*frag1);
	int data_len = skb->len - uc_hdr_len;
	int large_tail = 0, ret = NET_RX_DROP;
	uint16_t seqno;

	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (!primary_if)
		goto dropped;

	frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len);
	if (!frag_skb)
		goto dropped;
	skb_reserve(frag_skb, ucf_hdr_len);

	unicast_packet = (struct batadv_unicast_packet *)skb->data;
	memcpy(&tmp_uc, unicast_packet, uc_hdr_len);
	skb_split(skb, frag_skb, data_len / 2 + uc_hdr_len);

	if (batadv_skb_head_push(skb, ucf_hdr_len - uc_hdr_len) < 0 ||
	    batadv_skb_head_push(frag_skb, ucf_hdr_len) < 0)
		goto drop_frag;

	frag1 = (struct batadv_unicast_frag_packet *)skb->data;
	frag2 = (struct batadv_unicast_frag_packet *)frag_skb->data;

	memcpy(frag1, &tmp_uc, sizeof(tmp_uc));

	frag1->header.ttl--;
	frag1->header.version = BATADV_COMPAT_VERSION;
	frag1->header.packet_type = BATADV_UNICAST_FRAG;

	memcpy(frag1->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
	memcpy(frag2, frag1, sizeof(*frag2));

	if (data_len & 1)
		large_tail = BATADV_UNI_FRAG_LARGETAIL;

	frag1->flags = BATADV_UNI_FRAG_HEAD | large_tail;
	frag2->flags = large_tail;

	seqno = atomic_add_return(2, &hard_iface->frag_seqno);
	frag1->seqno = htons(seqno - 1);
	frag2->seqno = htons(seqno);

	batadv_send_skb_packet(skb, hard_iface, dstaddr);
	batadv_send_skb_packet(frag_skb, hard_iface, dstaddr);
	ret = NET_RX_SUCCESS;
	goto out;

drop_frag:
	kfree_skb(frag_skb);
dropped:
	kfree_skb(skb);
out:
	if (primary_if)
		batadv_hardif_free_ref(primary_if);
	return ret;
}

/**
 * batadv_unicast_push_and_fill_skb - extends the buffer and initializes the
 * common fields for unicast packets
 * @skb: packet
 * @hdr_size: amount of bytes to push at the beginning of the skb
 * @orig_node: the destination node
 *
 * Returns false if the buffer extension was not possible or true otherwise
 */
static bool batadv_unicast_push_and_fill_skb(struct sk_buff *skb, int hdr_size,
					     struct batadv_orig_node *orig_node)
{
	struct batadv_unicast_packet *unicast_packet;
	uint8_t ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);

	if (batadv_skb_head_push(skb, hdr_size) < 0)
		return false;

	unicast_packet = (struct batadv_unicast_packet *)skb->data;
	unicast_packet->header.version = BATADV_COMPAT_VERSION;
	/* batman packet type: unicast */
	unicast_packet->header.packet_type = BATADV_UNICAST;
	/* set unicast ttl */
	unicast_packet->header.ttl = BATADV_TTL;
	/* copy the destination for faster routing */
	memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN);
	/* set the destination tt version number */
	unicast_packet->ttvn = ttvn;

	return true;
}

/**
 * batadv_unicast_prepare_skb - encapsulate an skb with a unicast header
 * @skb: the skb containing the payload to encapsulate
 * @orig_node: the destination node
 *
 * Returns false if the payload could not be encapsulated or true otherwise
 */
static bool batadv_unicast_prepare_skb(struct sk_buff *skb,
				       struct batadv_orig_node *orig_node)
{
	size_t uni_size = sizeof(struct batadv_unicast_packet);
	return batadv_unicast_push_and_fill_skb(skb, uni_size, orig_node);
}

/**
 * batadv_unicast_4addr_prepare_skb - encapsulate an skb with a unicast4addr
 * header
 * @bat_priv: the bat priv with all the soft interface information
 * @skb: the skb containing the payload to encapsulate
 * @orig_node: the destination node
 * @packet_subtype: the batman 4addr packet subtype to use
 *
 * Returns false if the payload could not be encapsulated or true otherwise
 */
bool batadv_unicast_4addr_prepare_skb(struct batadv_priv *bat_priv,
				      struct sk_buff *skb,
				      struct batadv_orig_node *orig,
				      int packet_subtype)
{
	struct batadv_hard_iface *primary_if;
	struct batadv_unicast_4addr_packet *unicast_4addr_packet;
	bool ret = false;

	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (!primary_if)
		goto out;

	/* pull the header space and fill the unicast_packet substructure.
	 * We can do that because the first member of the unicast_4addr_packet
	 * is of type struct unicast_packet
	 */
	if (!batadv_unicast_push_and_fill_skb(skb,
					      sizeof(*unicast_4addr_packet),
					      orig))
		goto out;

	unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
	unicast_4addr_packet->u.header.packet_type = BATADV_UNICAST_4ADDR;
	memcpy(unicast_4addr_packet->src, primary_if->net_dev->dev_addr,
	       ETH_ALEN);
	unicast_4addr_packet->subtype = packet_subtype;
	unicast_4addr_packet->reserved = 0;

	ret = true;
out:
	if (primary_if)
		batadv_hardif_free_ref(primary_if);
	return ret;
}

/**
 * batadv_unicast_generic_send_skb - send an skb as unicast
 * @bat_priv: the bat priv with all the soft interface information
 * @skb: payload to send
 * @packet_type: the batman unicast packet type to use
 * @packet_subtype: the batman packet subtype. It is ignored if packet_type is
 *		    not BATADV_UNICAT_4ADDR
 *
 * Returns 1 in case of error or 0 otherwise
 */
int batadv_unicast_generic_send_skb(struct batadv_priv *bat_priv,
				    struct sk_buff *skb, int packet_type,
				    int packet_subtype)
{
	struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
	struct batadv_unicast_packet *unicast_packet;
	struct batadv_orig_node *orig_node;
	struct batadv_neigh_node *neigh_node;
	int data_len = skb->len;
	int ret = NET_RX_DROP;
	unsigned int dev_mtu;

	/* get routing information */
	if (is_multicast_ether_addr(ethhdr->h_dest)) {
		orig_node = batadv_gw_get_selected_orig(bat_priv);
		if (orig_node)
			goto find_router;
	}

	/* check for tt host - increases orig_node refcount.
	 * returns NULL in case of AP isolation
	 */
	orig_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
					     ethhdr->h_dest);

find_router:
	/* find_router():
	 *  - if orig_node is NULL it returns NULL
	 *  - increases neigh_nodes refcount if found.
	 */
	neigh_node = batadv_find_router(bat_priv, orig_node, NULL);

	if (!neigh_node)
		goto out;

	switch (packet_type) {
	case BATADV_UNICAST:
		batadv_unicast_prepare_skb(skb, orig_node);
		break;
	case BATADV_UNICAST_4ADDR:
		batadv_unicast_4addr_prepare_skb(bat_priv, skb, orig_node,
						 packet_subtype);
		break;
	default:
		/* this function supports UNICAST and UNICAST_4ADDR only. It
		 * should never be invoked with any other packet type
		 */
		goto out;
	}

	unicast_packet = (struct batadv_unicast_packet *)skb->data;

	/* inform the destination node that we are still missing a correct route
	 * for this client. The destination will receive this packet and will
	 * try to reroute it because the ttvn contained in the header is less
	 * than the current one
	 */
	if (batadv_tt_global_client_is_roaming(bat_priv, ethhdr->h_dest))
		unicast_packet->ttvn = unicast_packet->ttvn - 1;

	dev_mtu = neigh_node->if_incoming->net_dev->mtu;
	/* fragmentation mechanism only works for UNICAST (now) */
	if (packet_type == BATADV_UNICAST &&
	    atomic_read(&bat_priv->fragmentation) &&
	    data_len + sizeof(*unicast_packet) > dev_mtu) {
		/* send frag skb decreases ttl */
		unicast_packet->header.ttl++;
		ret = batadv_frag_send_skb(skb, bat_priv,
					   neigh_node->if_incoming,
					   neigh_node->addr);
		goto out;
	}

	if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
		ret = 0;

out:
	if (neigh_node)
		batadv_neigh_node_free_ref(neigh_node);
	if (orig_node)
		batadv_orig_node_free_ref(orig_node);
	if (ret == NET_RX_DROP)
		kfree_skb(skb);
	return ret;
}