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Sven Eckelmann0046b042016-01-01 00:01:03 +01001/* Copyright (C) 2013-2016 B.A.T.M.A.N. contributors:
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +02002 *
3 * Martin Hundebøll <martin@hundeboll.net>
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of version 2 of the GNU General Public
7 * License as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
Antonio Quartulliebf38fb2013-11-03 20:40:48 +010015 * along with this program; if not, see <http://www.gnu.org/licenses/>.
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +020016 */
17
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +020018#include "fragmentation.h"
Sven Eckelmann1e2c2a42015-04-17 19:40:28 +020019#include "main.h"
20
21#include <linux/atomic.h>
22#include <linux/byteorder/generic.h>
23#include <linux/etherdevice.h>
24#include <linux/fs.h>
25#include <linux/if_ether.h>
26#include <linux/jiffies.h>
27#include <linux/kernel.h>
Sven Eckelmann5274cd62015-06-21 14:45:15 +020028#include <linux/lockdep.h>
Sven Eckelmann1e2c2a42015-04-17 19:40:28 +020029#include <linux/netdevice.h>
Sven Eckelmann1e2c2a42015-04-17 19:40:28 +020030#include <linux/skbuff.h>
31#include <linux/slab.h>
32#include <linux/spinlock.h>
33#include <linux/string.h>
34
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +020035#include "hard-interface.h"
Sven Eckelmann1e2c2a42015-04-17 19:40:28 +020036#include "originator.h"
37#include "packet.h"
38#include "routing.h"
39#include "send.h"
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +020040#include "soft-interface.h"
41
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +020042/**
43 * batadv_frag_clear_chain - delete entries in the fragment buffer chain
44 * @head: head of chain with entries.
Sven Eckelmannbd687fe2016-07-17 21:04:00 +020045 * @dropped: whether the chain is cleared because all fragments are dropped
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +020046 *
47 * Free fragments in the passed hlist. Should be called with appropriate lock.
48 */
Sven Eckelmannbd687fe2016-07-17 21:04:00 +020049static void batadv_frag_clear_chain(struct hlist_head *head, bool dropped)
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +020050{
51 struct batadv_frag_list_entry *entry;
52 struct hlist_node *node;
53
54 hlist_for_each_entry_safe(entry, node, head, list) {
55 hlist_del(&entry->list);
Sven Eckelmannbd687fe2016-07-17 21:04:00 +020056
57 if (dropped)
58 kfree_skb(entry->skb);
59 else
60 consume_skb(entry->skb);
61
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +020062 kfree(entry);
63 }
64}
65
66/**
67 * batadv_frag_purge_orig - free fragments associated to an orig
68 * @orig_node: originator to free fragments from
69 * @check_cb: optional function to tell if an entry should be purged
70 */
71void batadv_frag_purge_orig(struct batadv_orig_node *orig_node,
72 bool (*check_cb)(struct batadv_frag_table_entry *))
73{
74 struct batadv_frag_table_entry *chain;
Sven Eckelmann6b5e9712015-05-26 18:34:26 +020075 u8 i;
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +020076
77 for (i = 0; i < BATADV_FRAG_BUFFER_COUNT; i++) {
78 chain = &orig_node->fragments[i];
Sven Eckelmann01f6b5c2015-08-26 10:31:50 +020079 spin_lock_bh(&chain->lock);
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +020080
81 if (!check_cb || check_cb(chain)) {
Sven Eckelmannbd687fe2016-07-17 21:04:00 +020082 batadv_frag_clear_chain(&chain->fragment_list, true);
Sven Eckelmann01f6b5c2015-08-26 10:31:50 +020083 chain->size = 0;
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +020084 }
85
Sven Eckelmann01f6b5c2015-08-26 10:31:50 +020086 spin_unlock_bh(&chain->lock);
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +020087 }
88}
89
90/**
91 * batadv_frag_size_limit - maximum possible size of packet to be fragmented
92 *
Sven Eckelmann62fe7102015-09-15 19:00:48 +020093 * Return: the maximum size of payload that can be fragmented.
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +020094 */
95static int batadv_frag_size_limit(void)
96{
97 int limit = BATADV_FRAG_MAX_FRAG_SIZE;
98
99 limit -= sizeof(struct batadv_frag_packet);
100 limit *= BATADV_FRAG_MAX_FRAGMENTS;
101
102 return limit;
103}
104
105/**
106 * batadv_frag_init_chain - check and prepare fragment chain for new fragment
107 * @chain: chain in fragments table to init
108 * @seqno: sequence number of the received fragment
109 *
110 * Make chain ready for a fragment with sequence number "seqno". Delete existing
111 * entries if they have an "old" sequence number.
112 *
113 * Caller must hold chain->lock.
114 *
Sven Eckelmann62fe7102015-09-15 19:00:48 +0200115 * Return: true if chain is empty and caller can just insert the new fragment
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200116 * without searching for the right position.
117 */
118static bool batadv_frag_init_chain(struct batadv_frag_table_entry *chain,
Sven Eckelmann6b5e9712015-05-26 18:34:26 +0200119 u16 seqno)
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200120{
Sven Eckelmann5274cd62015-06-21 14:45:15 +0200121 lockdep_assert_held(&chain->lock);
122
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200123 if (chain->seqno == seqno)
124 return false;
125
Sven Eckelmann176e5b72016-07-27 12:31:07 +0200126 if (!hlist_empty(&chain->fragment_list))
Sven Eckelmannbd687fe2016-07-17 21:04:00 +0200127 batadv_frag_clear_chain(&chain->fragment_list, true);
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200128
129 chain->size = 0;
130 chain->seqno = seqno;
131
132 return true;
133}
134
135/**
136 * batadv_frag_insert_packet - insert a fragment into a fragment chain
137 * @orig_node: originator that the fragment was received from
138 * @skb: skb to insert
139 * @chain_out: list head to attach complete chains of fragments to
140 *
141 * Insert a new fragment into the reverse ordered chain in the right table
142 * entry. The hash table entry is cleared if "old" fragments exist in it.
143 *
Sven Eckelmann62fe7102015-09-15 19:00:48 +0200144 * Return: true if skb is buffered, false on error. If the chain has all the
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200145 * fragments needed to merge the packet, the chain is moved to the passed head
146 * to avoid locking the chain in the table.
147 */
148static bool batadv_frag_insert_packet(struct batadv_orig_node *orig_node,
149 struct sk_buff *skb,
150 struct hlist_head *chain_out)
151{
152 struct batadv_frag_table_entry *chain;
153 struct batadv_frag_list_entry *frag_entry_new = NULL, *frag_entry_curr;
Sven Eckelmannd9124262014-05-26 17:21:39 +0200154 struct batadv_frag_list_entry *frag_entry_last = NULL;
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200155 struct batadv_frag_packet *frag_packet;
Sven Eckelmann6b5e9712015-05-26 18:34:26 +0200156 u8 bucket;
157 u16 seqno, hdr_size = sizeof(struct batadv_frag_packet);
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200158 bool ret = false;
159
160 /* Linearize packet to avoid linearizing 16 packets in a row when doing
161 * the later merge. Non-linear merge should be added to remove this
162 * linearization.
163 */
164 if (skb_linearize(skb) < 0)
165 goto err;
166
167 frag_packet = (struct batadv_frag_packet *)skb->data;
168 seqno = ntohs(frag_packet->seqno);
169 bucket = seqno % BATADV_FRAG_BUFFER_COUNT;
170
171 frag_entry_new = kmalloc(sizeof(*frag_entry_new), GFP_ATOMIC);
172 if (!frag_entry_new)
173 goto err;
174
175 frag_entry_new->skb = skb;
176 frag_entry_new->no = frag_packet->no;
177
178 /* Select entry in the "chain table" and delete any prior fragments
179 * with another sequence number. batadv_frag_init_chain() returns true,
180 * if the list is empty at return.
181 */
182 chain = &orig_node->fragments[bucket];
183 spin_lock_bh(&chain->lock);
184 if (batadv_frag_init_chain(chain, seqno)) {
Sven Eckelmann176e5b72016-07-27 12:31:07 +0200185 hlist_add_head(&frag_entry_new->list, &chain->fragment_list);
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200186 chain->size = skb->len - hdr_size;
187 chain->timestamp = jiffies;
Sven Eckelmann53e77142014-12-01 10:37:27 +0100188 chain->total_size = ntohs(frag_packet->total_size);
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200189 ret = true;
190 goto out;
191 }
192
193 /* Find the position for the new fragment. */
Sven Eckelmann176e5b72016-07-27 12:31:07 +0200194 hlist_for_each_entry(frag_entry_curr, &chain->fragment_list, list) {
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200195 /* Drop packet if fragment already exists. */
196 if (frag_entry_curr->no == frag_entry_new->no)
197 goto err_unlock;
198
199 /* Order fragments from highest to lowest. */
200 if (frag_entry_curr->no < frag_entry_new->no) {
201 hlist_add_before(&frag_entry_new->list,
202 &frag_entry_curr->list);
203 chain->size += skb->len - hdr_size;
204 chain->timestamp = jiffies;
205 ret = true;
206 goto out;
207 }
Sven Eckelmannd9124262014-05-26 17:21:39 +0200208
209 /* store current entry because it could be the last in list */
210 frag_entry_last = frag_entry_curr;
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200211 }
212
Sven Eckelmannd9124262014-05-26 17:21:39 +0200213 /* Reached the end of the list, so insert after 'frag_entry_last'. */
214 if (likely(frag_entry_last)) {
Sven Eckelmanne050dbe2014-08-15 10:19:39 +0200215 hlist_add_behind(&frag_entry_new->list, &frag_entry_last->list);
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200216 chain->size += skb->len - hdr_size;
217 chain->timestamp = jiffies;
218 ret = true;
219 }
220
221out:
222 if (chain->size > batadv_frag_size_limit() ||
Sven Eckelmann53e77142014-12-01 10:37:27 +0100223 chain->total_size != ntohs(frag_packet->total_size) ||
224 chain->total_size > batadv_frag_size_limit()) {
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200225 /* Clear chain if total size of either the list or the packet
Sven Eckelmann53e77142014-12-01 10:37:27 +0100226 * exceeds the maximum size of one merged packet. Don't allow
227 * packets to have different total_size.
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200228 */
Sven Eckelmannbd687fe2016-07-17 21:04:00 +0200229 batadv_frag_clear_chain(&chain->fragment_list, true);
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200230 chain->size = 0;
231 } else if (ntohs(frag_packet->total_size) == chain->size) {
232 /* All fragments received. Hand over chain to caller. */
Sven Eckelmann176e5b72016-07-27 12:31:07 +0200233 hlist_move_list(&chain->fragment_list, chain_out);
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200234 chain->size = 0;
235 }
236
237err_unlock:
238 spin_unlock_bh(&chain->lock);
239
240err:
241 if (!ret)
242 kfree(frag_entry_new);
243
244 return ret;
245}
246
247/**
248 * batadv_frag_merge_packets - merge a chain of fragments
249 * @chain: head of chain with fragments
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200250 *
251 * Expand the first skb in the chain and copy the content of the remaining
252 * skb's into the expanded one. After doing so, clear the chain.
253 *
Sven Eckelmann62fe7102015-09-15 19:00:48 +0200254 * Return: the merged skb or NULL on error.
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200255 */
256static struct sk_buff *
Sven Eckelmann83e8b872014-12-01 10:37:28 +0100257batadv_frag_merge_packets(struct hlist_head *chain)
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200258{
259 struct batadv_frag_packet *packet;
260 struct batadv_frag_list_entry *entry;
Sven Eckelmann422d2f72016-07-25 00:42:44 +0200261 struct sk_buff *skb_out;
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200262 int size, hdr_size = sizeof(struct batadv_frag_packet);
Sven Eckelmannbd687fe2016-07-17 21:04:00 +0200263 bool dropped = false;
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200264
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200265 /* Remove first entry, as this is the destination for the rest of the
266 * fragments.
267 */
268 entry = hlist_entry(chain->first, struct batadv_frag_list_entry, list);
269 hlist_del(&entry->list);
270 skb_out = entry->skb;
271 kfree(entry);
272
Sven Eckelmann83e8b872014-12-01 10:37:28 +0100273 packet = (struct batadv_frag_packet *)skb_out->data;
274 size = ntohs(packet->total_size);
275
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200276 /* Make room for the rest of the fragments. */
Sven Eckelmann5b6698b2014-12-20 13:48:55 +0100277 if (pskb_expand_head(skb_out, 0, size - skb_out->len, GFP_ATOMIC) < 0) {
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200278 kfree_skb(skb_out);
279 skb_out = NULL;
Sven Eckelmannbd687fe2016-07-17 21:04:00 +0200280 dropped = true;
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200281 goto free;
282 }
283
284 /* Move the existing MAC header to just before the payload. (Override
285 * the fragment header.)
286 */
287 skb_pull_rcsum(skb_out, hdr_size);
288 memmove(skb_out->data - ETH_HLEN, skb_mac_header(skb_out), ETH_HLEN);
289 skb_set_mac_header(skb_out, -ETH_HLEN);
290 skb_reset_network_header(skb_out);
291 skb_reset_transport_header(skb_out);
292
293 /* Copy the payload of the each fragment into the last skb */
294 hlist_for_each_entry(entry, chain, list) {
295 size = entry->skb->len - hdr_size;
296 memcpy(skb_put(skb_out, size), entry->skb->data + hdr_size,
297 size);
298 }
299
300free:
301 /* Locking is not needed, because 'chain' is not part of any orig. */
Sven Eckelmannbd687fe2016-07-17 21:04:00 +0200302 batadv_frag_clear_chain(chain, dropped);
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200303 return skb_out;
304}
305
306/**
307 * batadv_frag_skb_buffer - buffer fragment for later merge
308 * @skb: skb to buffer
309 * @orig_node_src: originator that the skb is received from
310 *
311 * Add fragment to buffer and merge fragments if possible.
312 *
313 * There are three possible outcomes: 1) Packet is merged: Return true and
314 * set *skb to merged packet; 2) Packet is buffered: Return true and set *skb
315 * to NULL; 3) Error: Return false and leave skb as is.
Sven Eckelmann62fe7102015-09-15 19:00:48 +0200316 *
317 * Return: true when packet is merged or buffered, false when skb is not not
318 * used.
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200319 */
320bool batadv_frag_skb_buffer(struct sk_buff **skb,
321 struct batadv_orig_node *orig_node_src)
322{
323 struct sk_buff *skb_out = NULL;
324 struct hlist_head head = HLIST_HEAD_INIT;
325 bool ret = false;
326
327 /* Add packet to buffer and table entry if merge is possible. */
328 if (!batadv_frag_insert_packet(orig_node_src, *skb, &head))
329 goto out_err;
330
331 /* Leave if more fragments are needed to merge. */
332 if (hlist_empty(&head))
333 goto out;
334
Sven Eckelmann83e8b872014-12-01 10:37:28 +0100335 skb_out = batadv_frag_merge_packets(&head);
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200336 if (!skb_out)
337 goto out_err;
338
339out:
340 *skb = skb_out;
341 ret = true;
342out_err:
343 return ret;
344}
345
346/**
347 * batadv_frag_skb_fwd - forward fragments that would exceed MTU when merged
348 * @skb: skb to forward
349 * @recv_if: interface that the skb is received on
350 * @orig_node_src: originator that the skb is received from
351 *
352 * Look up the next-hop of the fragments payload and check if the merged packet
353 * will exceed the MTU towards the next-hop. If so, the fragment is forwarded
354 * without merging it.
355 *
Sven Eckelmann62fe7102015-09-15 19:00:48 +0200356 * Return: true if the fragment is consumed/forwarded, false otherwise.
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200357 */
358bool batadv_frag_skb_fwd(struct sk_buff *skb,
359 struct batadv_hard_iface *recv_if,
360 struct batadv_orig_node *orig_node_src)
361{
362 struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
Sven Eckelmann422d2f72016-07-25 00:42:44 +0200363 struct batadv_orig_node *orig_node_dst;
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200364 struct batadv_neigh_node *neigh_node = NULL;
365 struct batadv_frag_packet *packet;
Sven Eckelmann6b5e9712015-05-26 18:34:26 +0200366 u16 total_size;
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200367 bool ret = false;
368
369 packet = (struct batadv_frag_packet *)skb->data;
370 orig_node_dst = batadv_orig_hash_find(bat_priv, packet->dest);
371 if (!orig_node_dst)
372 goto out;
373
374 neigh_node = batadv_find_router(bat_priv, orig_node_dst, recv_if);
375 if (!neigh_node)
376 goto out;
377
378 /* Forward the fragment, if the merged packet would be too big to
379 * be assembled.
380 */
381 total_size = ntohs(packet->total_size);
382 if (total_size > neigh_node->if_incoming->net_dev->mtu) {
383 batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_FWD);
384 batadv_add_counter(bat_priv, BATADV_CNT_FRAG_FWD_BYTES,
385 skb->len + ETH_HLEN);
386
Simon Wunderlicha40d9b02013-12-02 20:38:31 +0100387 packet->ttl--;
Antonio Quartulli95d39272016-01-16 16:40:15 +0800388 batadv_send_unicast_skb(skb, neigh_node);
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200389 ret = true;
390 }
391
392out:
393 if (orig_node_dst)
Sven Eckelmann5d967312016-01-17 11:01:09 +0100394 batadv_orig_node_put(orig_node_dst);
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200395 if (neigh_node)
Sven Eckelmann25bb2502016-01-17 11:01:11 +0100396 batadv_neigh_node_put(neigh_node);
Martin Hundebøll610bfc6bc2013-05-23 16:53:02 +0200397 return ret;
398}
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200399
400/**
401 * batadv_frag_create - create a fragment from skb
402 * @skb: skb to create fragment from
403 * @frag_head: header to use in new fragment
404 * @mtu: size of new fragment
405 *
406 * Split the passed skb into two fragments: A new one with size matching the
407 * passed mtu and the old one with the rest. The new skb contains data from the
408 * tail of the old skb.
409 *
Sven Eckelmann62fe7102015-09-15 19:00:48 +0200410 * Return: the new fragment, NULL on error.
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200411 */
412static struct sk_buff *batadv_frag_create(struct sk_buff *skb,
413 struct batadv_frag_packet *frag_head,
414 unsigned int mtu)
415{
416 struct sk_buff *skb_fragment;
Sven Eckelmannd3abce72016-03-09 22:22:51 +0100417 unsigned int header_size = sizeof(*frag_head);
418 unsigned int fragment_size = mtu - header_size;
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200419
420 skb_fragment = netdev_alloc_skb(NULL, mtu + ETH_HLEN);
421 if (!skb_fragment)
422 goto err;
423
Andrew Lunn19148482016-05-09 20:03:35 +0200424 skb_fragment->priority = skb->priority;
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200425
426 /* Eat the last mtu-bytes of the skb */
427 skb_reserve(skb_fragment, header_size + ETH_HLEN);
428 skb_split(skb, skb_fragment, skb->len - fragment_size);
429
430 /* Add the header */
431 skb_push(skb_fragment, header_size);
432 memcpy(skb_fragment->data, frag_head, header_size);
433
434err:
435 return skb_fragment;
436}
437
438/**
439 * batadv_frag_send_packet - create up to 16 fragments from the passed skb
440 * @skb: skb to create fragments from
441 * @orig_node: final destination of the created fragments
442 * @neigh_node: next-hop of the created fragments
443 *
Antonio Quartullif50ca952016-05-18 11:38:48 +0200444 * Return: the netdev tx status or -1 in case of error.
445 * When -1 is returned the skb is not consumed.
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200446 */
Antonio Quartullif50ca952016-05-18 11:38:48 +0200447int batadv_frag_send_packet(struct sk_buff *skb,
448 struct batadv_orig_node *orig_node,
449 struct batadv_neigh_node *neigh_node)
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200450{
451 struct batadv_priv *bat_priv;
Antonio Quartullibe181012014-04-23 14:05:16 +0200452 struct batadv_hard_iface *primary_if = NULL;
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200453 struct batadv_frag_packet frag_header;
454 struct sk_buff *skb_fragment;
Sven Eckelmannd3abce72016-03-09 22:22:51 +0100455 unsigned int mtu = neigh_node->if_incoming->net_dev->mtu;
456 unsigned int header_size = sizeof(frag_header);
457 unsigned int max_fragment_size, max_packet_size;
Antonio Quartullif50ca952016-05-18 11:38:48 +0200458 int ret = -1;
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200459
460 /* To avoid merge and refragmentation at next-hops we never send
461 * fragments larger than BATADV_FRAG_MAX_FRAG_SIZE
462 */
Sven Eckelmannd3abce72016-03-09 22:22:51 +0100463 mtu = min_t(unsigned int, mtu, BATADV_FRAG_MAX_FRAG_SIZE);
Sven Eckelmann0402e442014-12-20 13:48:56 +0100464 max_fragment_size = mtu - header_size;
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200465 max_packet_size = max_fragment_size * BATADV_FRAG_MAX_FRAGMENTS;
466
467 /* Don't even try to fragment, if we need more than 16 fragments */
468 if (skb->len > max_packet_size)
Antonio Quartullif50ca952016-05-18 11:38:48 +0200469 goto out;
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200470
471 bat_priv = orig_node->bat_priv;
472 primary_if = batadv_primary_if_get_selected(bat_priv);
473 if (!primary_if)
Antonio Quartullif50ca952016-05-18 11:38:48 +0200474 goto out;
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200475
476 /* Create one header to be copied to all fragments */
Simon Wunderlicha40d9b02013-12-02 20:38:31 +0100477 frag_header.packet_type = BATADV_UNICAST_FRAG;
478 frag_header.version = BATADV_COMPAT_VERSION;
479 frag_header.ttl = BATADV_TTL;
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200480 frag_header.seqno = htons(atomic_inc_return(&bat_priv->frag_seqno));
481 frag_header.reserved = 0;
482 frag_header.no = 0;
483 frag_header.total_size = htons(skb->len);
Andrew Lunnc0f25c802016-05-09 20:03:36 +0200484
485 /* skb->priority values from 256->263 are magic values to
486 * directly indicate a specific 802.1d priority. This is used
487 * to allow 802.1d priority to be passed directly in from VLAN
488 * tags, etc.
489 */
490 if (skb->priority >= 256 && skb->priority <= 263)
491 frag_header.priority = skb->priority - 256;
492
Antonio Quartulli8fdd0152014-01-22 00:42:11 +0100493 ether_addr_copy(frag_header.orig, primary_if->net_dev->dev_addr);
494 ether_addr_copy(frag_header.dest, orig_node->orig);
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200495
496 /* Eat and send fragments from the tail of skb */
497 while (skb->len > max_fragment_size) {
498 skb_fragment = batadv_frag_create(skb, &frag_header, mtu);
499 if (!skb_fragment)
Antonio Quartullif50ca952016-05-18 11:38:48 +0200500 goto out;
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200501
502 batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_TX);
503 batadv_add_counter(bat_priv, BATADV_CNT_FRAG_TX_BYTES,
504 skb_fragment->len + ETH_HLEN);
Antonio Quartullif50ca952016-05-18 11:38:48 +0200505 ret = batadv_send_unicast_skb(skb_fragment, neigh_node);
506 if (ret != NET_XMIT_SUCCESS) {
507 /* return -1 so that the caller can free the original
508 * skb
509 */
510 ret = -1;
511 goto out;
512 }
513
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200514 frag_header.no++;
515
516 /* The initial check in this function should cover this case */
Antonio Quartullif50ca952016-05-18 11:38:48 +0200517 if (frag_header.no == BATADV_FRAG_MAX_FRAGMENTS - 1) {
518 ret = -1;
519 goto out;
520 }
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200521 }
522
523 /* Make room for the fragment header. */
524 if (batadv_skb_head_push(skb, header_size) < 0 ||
525 pskb_expand_head(skb, header_size + ETH_HLEN, 0, GFP_ATOMIC) < 0)
Antonio Quartullif50ca952016-05-18 11:38:48 +0200526 goto out;
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200527
528 memcpy(skb->data, &frag_header, header_size);
529
530 /* Send the last fragment */
531 batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_TX);
532 batadv_add_counter(bat_priv, BATADV_CNT_FRAG_TX_BYTES,
533 skb->len + ETH_HLEN);
Antonio Quartullif50ca952016-05-18 11:38:48 +0200534 ret = batadv_send_unicast_skb(skb, neigh_node);
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200535
Antonio Quartullif50ca952016-05-18 11:38:48 +0200536out:
Antonio Quartullibe181012014-04-23 14:05:16 +0200537 if (primary_if)
Sven Eckelmann82047ad2016-01-17 11:01:10 +0100538 batadv_hardif_put(primary_if);
Antonio Quartullibe181012014-04-23 14:05:16 +0200539
540 return ret;
Martin Hundebøllee75ed82013-05-23 16:53:03 +0200541}