unicast.c 9.0 KB
Newer Older
1
/*
2
 * Copyright (C) 2010-2011 B.A.T.M.A.N. contributors:
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
 *
 * 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;
42 43
	int hdr_len = sizeof(struct unicast_packet);
	int uni_diff = sizeof(struct unicast_frag_packet) - hdr_len;
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

	/* 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;
	}

	skb_pull(tmp_skb, sizeof(struct unicast_frag_packet));
	if (pskb_expand_head(skb, 0, tmp_skb->len, GFP_ATOMIC) < 0) {
		/* free buffered skb, skb will be freed later */
		kfree_skb(tfp->skb);
		return NULL;
	}

	/* 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;
}

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(struct frag_packet_list_entry),
			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,
						 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;
	spin_lock_bh(&bat_priv->orig_hash_lock);
182
	rcu_read_lock();
183 184 185
	orig_node = ((struct orig_node *)
		    hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
			      unicast_packet->orig));
186
	rcu_read_unlock();
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

	if (!orig_node) {
		pr_debug("couldn't find originator in orig_hash\n");
		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:
	spin_unlock_bh(&bat_priv->orig_hash_lock);

	return ret;
}

int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
		  struct batman_if *batman_if, uint8_t dstaddr[])
{
	struct unicast_packet tmp_uc, *unicast_packet;
	struct sk_buff *frag_skb;
	struct unicast_frag_packet *frag1, *frag2;
	int uc_hdr_len = sizeof(struct unicast_packet);
	int ucf_hdr_len = sizeof(struct unicast_frag_packet);
229
	int data_len = skb->len - uc_hdr_len;
230
	int large_tail = 0;
231
	uint16_t seqno;
232 233 234 235

	if (!bat_priv->primary_if)
		goto dropped;

236 237 238
	frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len);
	if (!frag_skb)
		goto dropped;
239
	skb_reserve(frag_skb, ucf_hdr_len);
240

241
	unicast_packet = (struct unicast_packet *) skb->data;
242
	memcpy(&tmp_uc, unicast_packet, uc_hdr_len);
243
	skb_split(skb, frag_skb, data_len / 2 + uc_hdr_len);
244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260

	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(struct unicast_packet));

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

	memcpy(frag1->orig, bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
	memcpy(frag2, frag1, sizeof(struct unicast_frag_packet));

261 262 263 264 265
	if (data_len & 1)
		large_tail = UNI_FRAG_LARGETAIL;

	frag1->flags = UNI_FRAG_HEAD | large_tail;
	frag2->flags = large_tail;
266

267 268 269
	seqno = atomic_add_return(2, &batman_if->frag_seqno);
	frag1->seqno = htons(seqno - 1);
	frag2->seqno = htons(seqno);
270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285

	send_skb_packet(skb, batman_if, dstaddr);
	send_skb_packet(frag_skb, batman_if, dstaddr);
	return NET_RX_SUCCESS;

drop_frag:
	kfree_skb(frag_skb);
dropped:
	kfree_skb(skb);
	return NET_RX_DROP;
}

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;
286
	struct orig_node *orig_node = NULL;
287
	struct batman_if *batman_if;
288
	struct neigh_node *neigh_node;
289 290
	int data_len = skb->len;
	uint8_t dstaddr[6];
291
	int ret = 1;
292 293 294 295

	spin_lock_bh(&bat_priv->orig_hash_lock);

	/* get routing information */
296
	if (is_multicast_ether_addr(ethhdr->h_dest)) {
297
		orig_node = (struct orig_node *)gw_get_selected(bat_priv);
298
		if (orig_node)
299 300
			goto find_router;
	}
301

302 303
	/* check for hna host - increases orig_node refcount */
	orig_node = transtable_search(bat_priv, ethhdr->h_dest);
304

305
find_router:
306
	/* find_router() increases neigh_nodes refcount if found. */
307
	neigh_node = find_router(bat_priv, orig_node, NULL);
308

309
	if (!neigh_node)
310 311
		goto unlock;

312 313
	if (neigh_node->if_incoming->if_status != IF_ACTIVE)
		goto unlock;
314 315

	if (my_skb_head_push(skb, sizeof(struct unicast_packet)) < 0)
316 317 318 319 320 321 322
		goto unlock;

	/* don't lock while sending the packets ... we therefore
	 * copy the required data before sending */
	batman_if = neigh_node->if_incoming;
	memcpy(dstaddr, neigh_node->addr, ETH_ALEN);
	spin_unlock_bh(&bat_priv->orig_hash_lock);
323 324 325 326 327 328 329 330 331 332 333 334 335

	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);

	if (atomic_read(&bat_priv->fragmentation) &&
	    data_len + sizeof(struct unicast_packet) >
336
						batman_if->net_dev->mtu) {
337 338
		/* send frag skb decreases ttl */
		unicast_packet->ttl++;
339 340
		ret = frag_send_skb(skb, bat_priv, batman_if, dstaddr);
		goto out;
341
	}
342

343
	send_skb_packet(skb, batman_if, dstaddr);
344 345
	ret = 0;
	goto out;
346 347 348

unlock:
	spin_unlock_bh(&bat_priv->orig_hash_lock);
349 350 351 352 353 354 355 356
out:
	if (neigh_node)
		neigh_node_free_ref(neigh_node);
	if (orig_node)
		kref_put(&orig_node->refcount, orig_node_free_ref);
	if (ret == 1)
		kfree_skb(skb);
	return ret;
357
}