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
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(struct unicast_packet);
43 int 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 if (skb_linearize(skb) < 0 || skb_linearize(tmp_skb) < 0)
54 goto err;
55
56 skb_pull(tmp_skb, sizeof(struct unicast_frag_packet));
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->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(struct frag_packet_list_entry),
103 GFP_ATOMIC);
104 if (!tfp) {
105 frag_list_free(head);
106 return -ENOMEM;
107 }
108 tfp->skb = NULL;
109 tfp->seqno = 0;
110 INIT_LIST_HEAD(&tfp->list);
111 list_add(&tfp->list, head);
112 }
113
114 return 0;
115 }
116
frag_search_packet(struct list_head * head,struct unicast_frag_packet * up)117 static struct frag_packet_list_entry *frag_search_packet(struct list_head *head,
118 struct unicast_frag_packet *up)
119 {
120 struct frag_packet_list_entry *tfp;
121 struct unicast_frag_packet *tmp_up = NULL;
122 uint16_t search_seqno;
123
124 if (up->flags & UNI_FRAG_HEAD)
125 search_seqno = ntohs(up->seqno)+1;
126 else
127 search_seqno = ntohs(up->seqno)-1;
128
129 list_for_each_entry(tfp, head, list) {
130
131 if (!tfp->skb)
132 continue;
133
134 if (tfp->seqno == ntohs(up->seqno))
135 goto mov_tail;
136
137 tmp_up = (struct unicast_frag_packet *)tfp->skb->data;
138
139 if (tfp->seqno == search_seqno) {
140
141 if ((tmp_up->flags & UNI_FRAG_HEAD) !=
142 (up->flags & UNI_FRAG_HEAD))
143 return tfp;
144 else
145 goto mov_tail;
146 }
147 }
148 return NULL;
149
150 mov_tail:
151 list_move_tail(&tfp->list, head);
152 return NULL;
153 }
154
frag_list_free(struct list_head * head)155 void frag_list_free(struct list_head *head)
156 {
157 struct frag_packet_list_entry *pf, *tmp_pf;
158
159 if (!list_empty(head)) {
160
161 list_for_each_entry_safe(pf, tmp_pf, head, list) {
162 kfree_skb(pf->skb);
163 list_del(&pf->list);
164 kfree(pf);
165 }
166 }
167 return;
168 }
169
170 /* frag_reassemble_skb():
171 * returns NET_RX_DROP if the operation failed - skb is left intact
172 * returns NET_RX_SUCCESS if the fragment was buffered (skb_new will be NULL)
173 * or the skb could be reassembled (skb_new will point to the new packet and
174 * skb was freed)
175 */
frag_reassemble_skb(struct sk_buff * skb,struct bat_priv * bat_priv,struct sk_buff ** new_skb)176 int frag_reassemble_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
177 struct sk_buff **new_skb)
178 {
179 struct orig_node *orig_node;
180 struct frag_packet_list_entry *tmp_frag_entry;
181 int ret = NET_RX_DROP;
182 struct unicast_frag_packet *unicast_packet =
183 (struct unicast_frag_packet *)skb->data;
184
185 *new_skb = NULL;
186
187 orig_node = orig_hash_find(bat_priv, unicast_packet->orig);
188 if (!orig_node)
189 goto out;
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;
213
214 out:
215 if (orig_node)
216 orig_node_free_ref(orig_node);
217 return ret;
218 }
219
frag_send_skb(struct sk_buff * skb,struct bat_priv * bat_priv,struct hard_iface * hard_iface,uint8_t dstaddr[])220 int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
221 struct hard_iface *hard_iface, uint8_t dstaddr[])
222 {
223 struct unicast_packet tmp_uc, *unicast_packet;
224 struct sk_buff *frag_skb;
225 struct unicast_frag_packet *frag1, *frag2;
226 int uc_hdr_len = sizeof(struct unicast_packet);
227 int ucf_hdr_len = sizeof(struct unicast_frag_packet);
228 int data_len = skb->len - uc_hdr_len;
229 int large_tail = 0;
230 uint16_t seqno;
231
232 if (!bat_priv->primary_if)
233 goto dropped;
234
235 frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len);
236 if (!frag_skb)
237 goto dropped;
238 skb_reserve(frag_skb, ucf_hdr_len);
239
240 unicast_packet = (struct unicast_packet *) skb->data;
241 memcpy(&tmp_uc, unicast_packet, uc_hdr_len);
242 skb_split(skb, frag_skb, data_len / 2 + uc_hdr_len);
243
244 if (my_skb_head_push(skb, ucf_hdr_len - uc_hdr_len) < 0 ||
245 my_skb_head_push(frag_skb, ucf_hdr_len) < 0)
246 goto drop_frag;
247
248 frag1 = (struct unicast_frag_packet *)skb->data;
249 frag2 = (struct unicast_frag_packet *)frag_skb->data;
250
251 memcpy(frag1, &tmp_uc, sizeof(struct unicast_packet));
252
253 frag1->ttl--;
254 frag1->version = COMPAT_VERSION;
255 frag1->packet_type = BAT_UNICAST_FRAG;
256
257 memcpy(frag1->orig, bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
258 memcpy(frag2, frag1, sizeof(struct unicast_frag_packet));
259
260 if (data_len & 1)
261 large_tail = UNI_FRAG_LARGETAIL;
262
263 frag1->flags = UNI_FRAG_HEAD | large_tail;
264 frag2->flags = large_tail;
265
266 seqno = atomic_add_return(2, &hard_iface->frag_seqno);
267 frag1->seqno = htons(seqno - 1);
268 frag2->seqno = htons(seqno);
269
270 send_skb_packet(skb, hard_iface, dstaddr);
271 send_skb_packet(frag_skb, hard_iface, dstaddr);
272 return NET_RX_SUCCESS;
273
274 drop_frag:
275 kfree_skb(frag_skb);
276 dropped:
277 kfree_skb(skb);
278 return NET_RX_DROP;
279 }
280
unicast_send_skb(struct sk_buff * skb,struct bat_priv * bat_priv)281 int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv)
282 {
283 struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
284 struct unicast_packet *unicast_packet;
285 struct orig_node *orig_node;
286 struct neigh_node *neigh_node;
287 int data_len = skb->len;
288 int ret = 1;
289
290 /* get routing information */
291 if (is_multicast_ether_addr(ethhdr->h_dest)) {
292 orig_node = (struct orig_node *)gw_get_selected(bat_priv);
293 if (orig_node)
294 goto find_router;
295 }
296
297 /* check for hna host - increases orig_node refcount */
298 orig_node = transtable_search(bat_priv, ethhdr->h_dest);
299
300 find_router:
301 /**
302 * find_router():
303 * - if orig_node is NULL it returns NULL
304 * - increases neigh_nodes refcount if found.
305 */
306 neigh_node = find_router(bat_priv, orig_node, NULL);
307
308 if (!neigh_node)
309 goto out;
310
311 if (neigh_node->if_incoming->if_status != IF_ACTIVE)
312 goto out;
313
314 if (my_skb_head_push(skb, sizeof(struct unicast_packet)) < 0)
315 goto out;
316
317 unicast_packet = (struct unicast_packet *)skb->data;
318
319 unicast_packet->version = COMPAT_VERSION;
320 /* batman packet type: unicast */
321 unicast_packet->packet_type = BAT_UNICAST;
322 /* set unicast ttl */
323 unicast_packet->ttl = TTL;
324 /* copy the destination for faster routing */
325 memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN);
326
327 if (atomic_read(&bat_priv->fragmentation) &&
328 data_len + sizeof(struct unicast_packet) >
329 neigh_node->if_incoming->net_dev->mtu) {
330 /* send frag skb decreases ttl */
331 unicast_packet->ttl++;
332 ret = frag_send_skb(skb, bat_priv,
333 neigh_node->if_incoming, neigh_node->addr);
334 goto out;
335 }
336
337 send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
338 ret = 0;
339 goto out;
340
341 out:
342 if (neigh_node)
343 neigh_node_free_ref(neigh_node);
344 if (orig_node)
345 orig_node_free_ref(orig_node);
346 if (ret == 1)
347 kfree_skb(skb);
348 return ret;
349 }
350