19f84bd443af3fa3d13ac5c0e6b4f2bab3aca092
[linux-3.10.git] / net / batman-adv / unicast.c
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
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
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
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
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
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  */
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
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
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 }