1 /*
2 * Copyright (C) 2010-2012 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
frag_merge_packet(struct list_head * head,struct frag_packet_list_entry * tfp,struct sk_buff * skb)34 static 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(*unicast_packet);
43 int uni_diff = sizeof(*up) - 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 if (skb_linearize(skb) < 0 || skb_linearize(tmp_skb) < 0)
54 goto err;
55
56 skb_pull(tmp_skb, sizeof(*up));
57 if (pskb_expand_head(skb, 0, tmp_skb->len, GFP_ATOMIC) < 0)
58 goto err;
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->header.packet_type = BAT_UNICAST;
71
72 return skb;
73
74 err:
75 /* free buffered skb, skb will be freed later */
76 kfree_skb(tfp->skb);
77 return NULL;
78 }
79
frag_create_entry(struct list_head * head,struct sk_buff * skb)80 static void frag_create_entry(struct list_head *head, struct sk_buff *skb)
81 {
82 struct frag_packet_list_entry *tfp;
83 struct unicast_frag_packet *up =
84 (struct unicast_frag_packet *)skb->data;
85
86 /* free and oldest packets stand at the end */
87 tfp = list_entry((head)->prev, typeof(*tfp), list);
88 kfree_skb(tfp->skb);
89
90 tfp->seqno = ntohs(up->seqno);
91 tfp->skb = skb;
92 list_move(&tfp->list, head);
93 return;
94 }
95
frag_create_buffer(struct list_head * head)96 static int frag_create_buffer(struct list_head *head)
97 {
98 int i;
99 struct frag_packet_list_entry *tfp;
100
101 for (i = 0; i < FRAG_BUFFER_SIZE; i++) {
102 tfp = kmalloc(sizeof(*tfp), GFP_ATOMIC);
103 if (!tfp) {
104 frag_list_free(head);
105 return -ENOMEM;
106 }
107 tfp->skb = NULL;
108 tfp->seqno = 0;
109 INIT_LIST_HEAD(&tfp->list);
110 list_add(&tfp->list, head);
111 }
112
113 return 0;
114 }
115
frag_search_packet(struct list_head * head,const struct unicast_frag_packet * up)116 static struct frag_packet_list_entry *frag_search_packet(struct list_head *head,
117 const struct unicast_frag_packet *up)
118 {
119 struct frag_packet_list_entry *tfp;
120 struct unicast_frag_packet *tmp_up = NULL;
121 uint16_t search_seqno;
122
123 if (up->flags & UNI_FRAG_HEAD)
124 search_seqno = ntohs(up->seqno)+1;
125 else
126 search_seqno = ntohs(up->seqno)-1;
127
128 list_for_each_entry(tfp, head, list) {
129
130 if (!tfp->skb)
131 continue;
132
133 if (tfp->seqno == ntohs(up->seqno))
134 goto mov_tail;
135
136 tmp_up = (struct unicast_frag_packet *)tfp->skb->data;
137
138 if (tfp->seqno == search_seqno) {
139
140 if ((tmp_up->flags & UNI_FRAG_HEAD) !=
141 (up->flags & UNI_FRAG_HEAD))
142 return tfp;
143 else
144 goto mov_tail;
145 }
146 }
147 return NULL;
148
149 mov_tail:
150 list_move_tail(&tfp->list, head);
151 return NULL;
152 }
153
frag_list_free(struct list_head * head)154 void frag_list_free(struct list_head *head)
155 {
156 struct frag_packet_list_entry *pf, *tmp_pf;
157
158 if (!list_empty(head)) {
159
160 list_for_each_entry_safe(pf, tmp_pf, head, list) {
161 kfree_skb(pf->skb);
162 list_del(&pf->list);
163 kfree(pf);
164 }
165 }
166 return;
167 }
168
169 /* frag_reassemble_skb():
170 * returns NET_RX_DROP if the operation failed - skb is left intact
171 * returns NET_RX_SUCCESS if the fragment was buffered (skb_new will be NULL)
172 * or the skb could be reassembled (skb_new will point to the new packet and
173 * skb was freed)
174 */
frag_reassemble_skb(struct sk_buff * skb,struct bat_priv * bat_priv,struct sk_buff ** new_skb)175 int frag_reassemble_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
176 struct sk_buff **new_skb)
177 {
178 struct orig_node *orig_node;
179 struct frag_packet_list_entry *tmp_frag_entry;
180 int ret = NET_RX_DROP;
181 struct unicast_frag_packet *unicast_packet =
182 (struct unicast_frag_packet *)skb->data;
183
184 *new_skb = NULL;
185
186 orig_node = orig_hash_find(bat_priv, unicast_packet->orig);
187 if (!orig_node)
188 goto out;
189
190 orig_node->last_frag_packet = jiffies;
191
192 if (list_empty(&orig_node->frag_list) &&
193 frag_create_buffer(&orig_node->frag_list)) {
194 pr_debug("couldn't create frag buffer\n");
195 goto out;
196 }
197
198 tmp_frag_entry = frag_search_packet(&orig_node->frag_list,
199 unicast_packet);
200
201 if (!tmp_frag_entry) {
202 frag_create_entry(&orig_node->frag_list, skb);
203 ret = NET_RX_SUCCESS;
204 goto out;
205 }
206
207 *new_skb = frag_merge_packet(&orig_node->frag_list, tmp_frag_entry,
208 skb);
209 /* if not, merge failed */
210 if (*new_skb)
211 ret = NET_RX_SUCCESS;
212
213 out:
214 if (orig_node)
215 orig_node_free_ref(orig_node);
216 return ret;
217 }
218
frag_send_skb(struct sk_buff * skb,struct bat_priv * bat_priv,struct hard_iface * hard_iface,const uint8_t dstaddr[])219 int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
220 struct hard_iface *hard_iface, const uint8_t dstaddr[])
221 {
222 struct unicast_packet tmp_uc, *unicast_packet;
223 struct hard_iface *primary_if;
224 struct sk_buff *frag_skb;
225 struct unicast_frag_packet *frag1, *frag2;
226 int uc_hdr_len = sizeof(*unicast_packet);
227 int ucf_hdr_len = sizeof(*frag1);
228 int data_len = skb->len - uc_hdr_len;
229 int large_tail = 0, ret = NET_RX_DROP;
230 uint16_t seqno;
231
232 primary_if = primary_if_get_selected(bat_priv);
233 if (!primary_if)
234 goto dropped;
235
236 frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len);
237 if (!frag_skb)
238 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 if (my_skb_head_push(skb, ucf_hdr_len - uc_hdr_len) < 0 ||
246 my_skb_head_push(frag_skb, ucf_hdr_len) < 0)
247 goto drop_frag;
248
249 frag1 = (struct unicast_frag_packet *)skb->data;
250 frag2 = (struct unicast_frag_packet *)frag_skb->data;
251
252 memcpy(frag1, &tmp_uc, sizeof(tmp_uc));
253
254 frag1->header.ttl--;
255 frag1->header.version = COMPAT_VERSION;
256 frag1->header.packet_type = BAT_UNICAST_FRAG;
257
258 memcpy(frag1->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
259 memcpy(frag2, frag1, sizeof(*frag2));
260
261 if (data_len & 1)
262 large_tail = UNI_FRAG_LARGETAIL;
263
264 frag1->flags = UNI_FRAG_HEAD | large_tail;
265 frag2->flags = large_tail;
266
267 seqno = atomic_add_return(2, &hard_iface->frag_seqno);
268 frag1->seqno = htons(seqno - 1);
269 frag2->seqno = htons(seqno);
270
271 send_skb_packet(skb, hard_iface, dstaddr);
272 send_skb_packet(frag_skb, hard_iface, dstaddr);
273 ret = NET_RX_SUCCESS;
274 goto out;
275
276 drop_frag:
277 kfree_skb(frag_skb);
278 dropped:
279 kfree_skb(skb);
280 out:
281 if (primary_if)
282 hardif_free_ref(primary_if);
283 return ret;
284 }
285
unicast_send_skb(struct sk_buff * skb,struct bat_priv * bat_priv)286 int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv)
287 {
288 struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
289 struct unicast_packet *unicast_packet;
290 struct orig_node *orig_node;
291 struct neigh_node *neigh_node;
292 int data_len = skb->len;
293 int ret = 1;
294
295 /* get routing information */
296 if (is_multicast_ether_addr(ethhdr->h_dest)) {
297 orig_node = gw_get_selected_orig(bat_priv);
298 if (orig_node)
299 goto find_router;
300 }
301
302 /* check for tt host - increases orig_node refcount.
303 * returns NULL in case of AP isolation */
304 orig_node = transtable_search(bat_priv, ethhdr->h_source,
305 ethhdr->h_dest);
306
307 find_router:
308 /**
309 * find_router():
310 * - if orig_node is NULL it returns NULL
311 * - increases neigh_nodes refcount if found.
312 */
313 neigh_node = find_router(bat_priv, orig_node, NULL);
314
315 if (!neigh_node)
316 goto out;
317
318 if (my_skb_head_push(skb, sizeof(*unicast_packet)) < 0)
319 goto out;
320
321 unicast_packet = (struct unicast_packet *)skb->data;
322
323 unicast_packet->header.version = COMPAT_VERSION;
324 /* batman packet type: unicast */
325 unicast_packet->header.packet_type = BAT_UNICAST;
326 /* set unicast ttl */
327 unicast_packet->header.ttl = TTL;
328 /* copy the destination for faster routing */
329 memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN);
330 /* set the destination tt version number */
331 unicast_packet->ttvn =
332 (uint8_t)atomic_read(&orig_node->last_ttvn);
333
334 if (atomic_read(&bat_priv->fragmentation) &&
335 data_len + sizeof(*unicast_packet) >
336 neigh_node->if_incoming->net_dev->mtu) {
337 /* send frag skb decreases ttl */
338 unicast_packet->header.ttl++;
339 ret = frag_send_skb(skb, bat_priv,
340 neigh_node->if_incoming, neigh_node->addr);
341 goto out;
342 }
343
344 send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
345 ret = 0;
346 goto out;
347
348 out:
349 if (neigh_node)
350 neigh_node_free_ref(neigh_node);
351 if (orig_node)
352 orig_node_free_ref(orig_node);
353 if (ret == 1)
354 kfree_skb(skb);
355 return ret;
356 }
357