unicast.c revision c2f7f0e7b3ce55eee32892d6aa5cd88a7512ea25 
1/*
2 * Copyright (C) 2010-2011 B.A.T.M.A.N. contributors:
3 *
4 * Andreas Langer
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of version 2 of the GNU General Public
8 * License as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
18 * 02110-1301, USA
19 *
20 */
21
22#include "main.h"
23#include "unicast.h"
24#include "send.h"
25#include "soft-interface.h"
26#include "gateway_client.h"
27#include "originator.h"
28#include "hash.h"
29#include "translation-table.h"
30#include "routing.h"
31#include "hard-interface.h"
32
33
34static struct sk_buff *frag_merge_packet(struct list_head *head,
35					 struct frag_packet_list_entry *tfp,
36					 struct sk_buff *skb)
37{
38	struct unicast_frag_packet *up =
39		(struct unicast_frag_packet *)skb->data;
40	struct sk_buff *tmp_skb;
41	struct unicast_packet *unicast_packet;
42	int hdr_len = sizeof(struct unicast_packet),
43	    uni_diff = sizeof(struct unicast_frag_packet) - hdr_len;
44
45	/* set skb to the first part and tmp_skb to the second part */
46	if (up->flags & UNI_FRAG_HEAD) {
47		tmp_skb = tfp->skb;
48	} else {
49		tmp_skb = skb;
50		skb = tfp->skb;
51	}
52
53	skb_pull(tmp_skb, sizeof(struct unicast_frag_packet));
54	if (pskb_expand_head(skb, 0, tmp_skb->len, GFP_ATOMIC) < 0) {
55		/* free buffered skb, skb will be freed later */
56		kfree_skb(tfp->skb);
57		return NULL;
58	}
59
60	/* move free entry to end */
61	tfp->skb = NULL;
62	tfp->seqno = 0;
63	list_move_tail(&tfp->list, head);
64
65	memcpy(skb_put(skb, tmp_skb->len), tmp_skb->data, tmp_skb->len);
66	kfree_skb(tmp_skb);
67
68	memmove(skb->data + uni_diff, skb->data, hdr_len);
69	unicast_packet = (struct unicast_packet *) skb_pull(skb, uni_diff);
70	unicast_packet->packet_type = BAT_UNICAST;
71
72	return skb;
73}
74
75static void frag_create_entry(struct list_head *head, struct sk_buff *skb)
76{
77	struct frag_packet_list_entry *tfp;
78	struct unicast_frag_packet *up =
79		(struct unicast_frag_packet *)skb->data;
80
81	/* free and oldest packets stand at the end */
82	tfp = list_entry((head)->prev, typeof(*tfp), list);
83	kfree_skb(tfp->skb);
84
85	tfp->seqno = ntohs(up->seqno);
86	tfp->skb = skb;
87	list_move(&tfp->list, head);
88	return;
89}
90
91static int frag_create_buffer(struct list_head *head)
92{
93	int i;
94	struct frag_packet_list_entry *tfp;
95
96	for (i = 0; i < FRAG_BUFFER_SIZE; i++) {
97		tfp = kmalloc(sizeof(struct frag_packet_list_entry),
98			GFP_ATOMIC);
99		if (!tfp) {
100			frag_list_free(head);
101			return -ENOMEM;
102		}
103		tfp->skb = NULL;
104		tfp->seqno = 0;
105		INIT_LIST_HEAD(&tfp->list);
106		list_add(&tfp->list, head);
107	}
108
109	return 0;
110}
111
112static struct frag_packet_list_entry *frag_search_packet(struct list_head *head,
113						 struct unicast_frag_packet *up)
114{
115	struct frag_packet_list_entry *tfp;
116	struct unicast_frag_packet *tmp_up = NULL;
117	uint16_t search_seqno;
118
119	if (up->flags & UNI_FRAG_HEAD)
120		search_seqno = ntohs(up->seqno)+1;
121	else
122		search_seqno = ntohs(up->seqno)-1;
123
124	list_for_each_entry(tfp, head, list) {
125
126		if (!tfp->skb)
127			continue;
128
129		if (tfp->seqno == ntohs(up->seqno))
130			goto mov_tail;
131
132		tmp_up = (struct unicast_frag_packet *)tfp->skb->data;
133
134		if (tfp->seqno == search_seqno) {
135
136			if ((tmp_up->flags & UNI_FRAG_HEAD) !=
137			    (up->flags & UNI_FRAG_HEAD))
138				return tfp;
139			else
140				goto mov_tail;
141		}
142	}
143	return NULL;
144
145mov_tail:
146	list_move_tail(&tfp->list, head);
147	return NULL;
148}
149
150void frag_list_free(struct list_head *head)
151{
152	struct frag_packet_list_entry *pf, *tmp_pf;
153
154	if (!list_empty(head)) {
155
156		list_for_each_entry_safe(pf, tmp_pf, head, list) {
157			kfree_skb(pf->skb);
158			list_del(&pf->list);
159			kfree(pf);
160		}
161	}
162	return;
163}
164
165/* frag_reassemble_skb():
166 * returns NET_RX_DROP if the operation failed - skb is left intact
167 * returns NET_RX_SUCCESS if the fragment was buffered (skb_new will be NULL)
168 * or the skb could be reassembled (skb_new will point to the new packet and
169 * skb was freed)
170 */
171int frag_reassemble_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
172			struct sk_buff **new_skb)
173{
174	struct orig_node *orig_node;
175	struct frag_packet_list_entry *tmp_frag_entry;
176	int ret = NET_RX_DROP;
177	struct unicast_frag_packet *unicast_packet =
178		(struct unicast_frag_packet *)skb->data;
179
180	*new_skb = NULL;
181	spin_lock_bh(&bat_priv->orig_hash_lock);
182	orig_node = ((struct orig_node *)
183		    hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
184			      unicast_packet->orig));
185
186	if (!orig_node) {
187		pr_debug("couldn't find originator in orig_hash\n");
188		goto out;
189	}
190
191	orig_node->last_frag_packet = jiffies;
192
193	if (list_empty(&orig_node->frag_list) &&
194	    frag_create_buffer(&orig_node->frag_list)) {
195		pr_debug("couldn't create frag buffer\n");
196		goto out;
197	}
198
199	tmp_frag_entry = frag_search_packet(&orig_node->frag_list,
200					    unicast_packet);
201
202	if (!tmp_frag_entry) {
203		frag_create_entry(&orig_node->frag_list, skb);
204		ret = NET_RX_SUCCESS;
205		goto out;
206	}
207
208	*new_skb = frag_merge_packet(&orig_node->frag_list, tmp_frag_entry,
209				     skb);
210	/* if not, merge failed */
211	if (*new_skb)
212		ret = NET_RX_SUCCESS;
213out:
214	spin_unlock_bh(&bat_priv->orig_hash_lock);
215
216	return ret;
217}
218
219int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
220		  struct batman_if *batman_if, uint8_t dstaddr[])
221{
222	struct unicast_packet tmp_uc, *unicast_packet;
223	struct sk_buff *frag_skb;
224	struct unicast_frag_packet *frag1, *frag2;
225	int uc_hdr_len = sizeof(struct unicast_packet);
226	int ucf_hdr_len = sizeof(struct unicast_frag_packet);
227	int data_len = skb->len - uc_hdr_len;
228	int large_tail = 0;
229	uint16_t seqno;
230
231	if (!bat_priv->primary_if)
232		goto dropped;
233
234	frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len);
235	if (!frag_skb)
236		goto dropped;
237	skb_reserve(frag_skb, ucf_hdr_len);
238
239	unicast_packet = (struct unicast_packet *) skb->data;
240	memcpy(&tmp_uc, unicast_packet, uc_hdr_len);
241	skb_split(skb, frag_skb, data_len / 2 + uc_hdr_len);
242
243	if (my_skb_head_push(skb, ucf_hdr_len - uc_hdr_len) < 0 ||
244	    my_skb_head_push(frag_skb, ucf_hdr_len) < 0)
245		goto drop_frag;
246
247	frag1 = (struct unicast_frag_packet *)skb->data;
248	frag2 = (struct unicast_frag_packet *)frag_skb->data;
249
250	memcpy(frag1, &tmp_uc, sizeof(struct unicast_packet));
251
252	frag1->ttl--;
253	frag1->version = COMPAT_VERSION;
254	frag1->packet_type = BAT_UNICAST_FRAG;
255
256	memcpy(frag1->orig, bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
257	memcpy(frag2, frag1, sizeof(struct unicast_frag_packet));
258
259	if (data_len & 1)
260		large_tail = UNI_FRAG_LARGETAIL;
261
262	frag1->flags = UNI_FRAG_HEAD | large_tail;
263	frag2->flags = large_tail;
264
265	seqno = atomic_add_return(2, &batman_if->frag_seqno);
266	frag1->seqno = htons(seqno - 1);
267	frag2->seqno = htons(seqno);
268
269	send_skb_packet(skb, batman_if, dstaddr);
270	send_skb_packet(frag_skb, batman_if, dstaddr);
271	return NET_RX_SUCCESS;
272
273drop_frag:
274	kfree_skb(frag_skb);
275dropped:
276	kfree_skb(skb);
277	return NET_RX_DROP;
278}
279
280int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv)
281{
282	struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
283	struct unicast_packet *unicast_packet;
284	struct orig_node *orig_node;
285	struct batman_if *batman_if;
286	struct neigh_node *router;
287	int data_len = skb->len;
288	uint8_t dstaddr[6];
289
290	spin_lock_bh(&bat_priv->orig_hash_lock);
291
292	/* get routing information */
293	if (is_multicast_ether_addr(ethhdr->h_dest))
294		orig_node = (struct orig_node *)gw_get_selected(bat_priv);
295	else
296		orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash,
297							   compare_orig,
298							   choose_orig,
299							   ethhdr->h_dest));
300
301	/* check for hna host */
302	if (!orig_node)
303		orig_node = transtable_search(bat_priv, ethhdr->h_dest);
304
305	router = find_router(bat_priv, orig_node, NULL);
306
307	if (!router)
308		goto unlock;
309
310	/* don't lock while sending the packets ... we therefore
311		* copy the required data before sending */
312
313	batman_if = router->if_incoming;
314	memcpy(dstaddr, router->addr, ETH_ALEN);
315
316	spin_unlock_bh(&bat_priv->orig_hash_lock);
317
318	if (batman_if->if_status != IF_ACTIVE)
319		goto dropped;
320
321	if (my_skb_head_push(skb, sizeof(struct unicast_packet)) < 0)
322		goto dropped;
323
324	unicast_packet = (struct unicast_packet *)skb->data;
325
326	unicast_packet->version = COMPAT_VERSION;
327	/* batman packet type: unicast */
328	unicast_packet->packet_type = BAT_UNICAST;
329	/* set unicast ttl */
330	unicast_packet->ttl = TTL;
331	/* copy the destination for faster routing */
332	memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN);
333
334	if (atomic_read(&bat_priv->fragmentation) &&
335	    data_len + sizeof(struct unicast_packet) >
336	    batman_if->net_dev->mtu) {
337		/* send frag skb decreases ttl */
338		unicast_packet->ttl++;
339		return frag_send_skb(skb, bat_priv, batman_if,
340				     dstaddr);
341	}
342	send_skb_packet(skb, batman_if, dstaddr);
343	return 0;
344
345unlock:
346	spin_unlock_bh(&bat_priv->orig_hash_lock);
347dropped:
348	kfree_skb(skb);
349	return 1;
350}
351