summaryrefslogtreecommitdiffstats
path: root/net/batman-adv/unicast.c
blob: 32b125fb3d3b65ce07d7b83ad5b574257b0cd250 (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
/*
 * Copyright (C) 2010-2011 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 *frag_merge_packet(struct list_head *head,
					 struct frag_packet_list_entry *tfp,
					 struct sk_buff *skb)
{
	struct unicast_frag_packet *up =
		(struct unicast_frag_packet *)skb->data;
	struct sk_buff *tmp_skb;
	struct unicast_packet *unicast_packet;
	int hdr_len = sizeof(*unicast_packet);
	int uni_diff = sizeof(*up) - hdr_len;

	/* set skb to the first part and tmp_skb to the second part */
	if (up->flags & 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);
	unicast_packet = (struct unicast_packet *) skb_pull(skb, uni_diff);
	unicast_packet->packet_type = BAT_UNICAST;

	return skb;

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

static void frag_create_entry(struct list_head *head, struct sk_buff *skb)
{
	struct frag_packet_list_entry *tfp;
	struct unicast_frag_packet *up =
		(struct 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 frag_create_buffer(struct list_head *head)
{
	int i;
	struct frag_packet_list_entry *tfp;

	for (i = 0; i < FRAG_BUFFER_SIZE; i++) {
		tfp = kmalloc(sizeof(*tfp), GFP_ATOMIC);
		if (!tfp) {
			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 frag_packet_list_entry *frag_search_packet(struct list_head *head,
					   const struct unicast_frag_packet *up)
{
	struct frag_packet_list_entry *tfp;
	struct unicast_frag_packet *tmp_up = NULL;
	uint16_t search_seqno;

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

	list_for_each_entry(tfp, head, list) {

		if (!tfp->skb)
			continue;

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

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

		if (tfp->seqno == search_seqno) {

			if ((tmp_up->flags & UNI_FRAG_HEAD) !=
			    (up->flags & UNI_FRAG_HEAD))
				return tfp;
			else
				goto mov_tail;
		}
	}
	return NULL;

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

void frag_list_free(struct list_head *head)
{
	struct 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 frag_reassemble_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
			struct sk_buff **new_skb)
{
	struct orig_node *orig_node;
	struct frag_packet_list_entry *tmp_frag_entry;
	int ret = NET_RX_DROP;
	struct unicast_frag_packet *unicast_packet =
		(struct unicast_frag_packet *)skb->data;

	*new_skb = NULL;

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

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

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

	*new_skb = 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)
		orig_node_free_ref(orig_node);
	return ret;
}

int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
		  struct hard_iface *hard_iface, const uint8_t dstaddr[])
{
	struct unicast_packet tmp_uc, *unicast_packet;
	struct hard_iface *primary_if;
	struct sk_buff *frag_skb;
	struct 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 = 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 unicast_packet *) skb->data;
	memcpy(&tmp_uc, unicast_packet, uc_hdr_len);
	skb_split(skb, frag_skb, data_len / 2 + uc_hdr_len);

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

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

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

	frag1->ttl--;
	frag1->version = COMPAT_VERSION;
	frag1->packet_type = BAT_UNICAST_FRAG;

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

	if (data_len & 1)
		large_tail = UNI_FRAG_LARGETAIL;

	frag1->flags = 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);

	send_skb_packet(skb, hard_iface, dstaddr);
	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)
		hardif_free_ref(primary_if);
	return ret;
}

int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv)
{
	struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
	struct unicast_packet *unicast_packet;
	struct orig_node *orig_node;
	struct neigh_node *neigh_node;
	int data_len = skb->len;
	int ret = 1;

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

	/* check for tt host - increases orig_node refcount */
	orig_node = transtable_search(bat_priv, ethhdr->h_dest);

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

	if (!neigh_node)
		goto out;

	if (my_skb_head_push(skb, sizeof(*unicast_packet)) < 0)
		goto out;

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

	unicast_packet->version = COMPAT_VERSION;
	/* batman packet type: unicast */
	unicast_packet->packet_type = BAT_UNICAST;
	/* set unicast ttl */
	unicast_packet->ttl = 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 =
		(uint8_t)atomic_read(&orig_node->last_ttvn);

	if (atomic_read(&bat_priv->fragmentation) &&
	    data_len + sizeof(*unicast_packet) >
				neigh_node->if_incoming->net_dev->mtu) {
		/* send frag skb decreases ttl */
		unicast_packet->ttl++;
		ret = frag_send_skb(skb, bat_priv,
				    neigh_node->if_incoming, neigh_node->addr);
		goto out;
	}

	send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
	ret = 0;
	goto out;

out:
	if (neigh_node)
		neigh_node_free_ref(neigh_node);
	if (orig_node)
		orig_node_free_ref(orig_node);
	if (ret == 1)
		kfree_skb(skb);
	return ret;
}