drivers/staging/batman-adv/unicast.c

   1 /*
   2  * Copyright (C) 2010 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 "hash.h"
  27 #include "translation-table.h"
  28 #include "routing.h"
  29 #include "hard-interface.h"
  30
  31
  32 static struct sk_buff *frag_merge_packet(struct list_head *head,
  33                                          struct frag_packet_list_entry *tfp,
  34                                          struct sk_buff *skb)
  35 {
  36         struct unicast_frag_packet *up =
  37                 (struct unicast_frag_packet *)skb->data;
  38         struct sk_buff *tmp_skb;
  39         struct unicast_packet *unicast_packet;
  40         int hdr_len = sizeof(struct unicast_packet),
  41             uni_diff = sizeof(struct unicast_frag_packet) - hdr_len;
  42
  43         /* set skb to the first part and tmp_skb to the second part */
  44         if (up->flags & UNI_FRAG_HEAD) {
  45                 tmp_skb = tfp->skb;
  46         } else {
  47                 tmp_skb = skb;
  48                 skb = tfp->skb;
  49         }
  50
  51         skb_pull(tmp_skb, sizeof(struct unicast_frag_packet));
  52         if (pskb_expand_head(skb, 0, tmp_skb->len, GFP_ATOMIC) < 0) {
  53                 /* free buffered skb, skb will be freed later */
  54                 kfree_skb(tfp->skb);
  55                 return NULL;
  56         }
  57
  58         /* move free entry to end */
  59         tfp->skb = NULL;
  60         tfp->seqno = 0;
  61         list_move_tail(&tfp->list, head);
  62
  63         memcpy(skb_put(skb, tmp_skb->len), tmp_skb->data, tmp_skb->len);
  64         kfree_skb(tmp_skb);
  65
  66         memmove(skb->data + uni_diff, skb->data, hdr_len);
  67         unicast_packet = (struct unicast_packet *) skb_pull(skb, uni_diff);
  68         unicast_packet->packet_type = BAT_UNICAST;
  69
  70         return skb;
  71 }
  72
  73 static void frag_create_entry(struct list_head *head, struct sk_buff *skb)
  74 {
  75         struct frag_packet_list_entry *tfp;
  76         struct unicast_frag_packet *up =
  77                 (struct unicast_frag_packet *)skb->data;
  78
  79         /* free and oldest packets stand at the end */
  80         tfp = list_entry((head)->prev, typeof(*tfp), list);
  81         kfree_skb(tfp->skb);
  82
  83         tfp->seqno = ntohs(up->seqno);
  84         tfp->skb = skb;
  85         list_move(&tfp->list, head);
  86         return;
  87 }
  88
  89 static int frag_create_buffer(struct list_head *head)
  90 {
  91         int i;
  92         struct frag_packet_list_entry *tfp;
  93
  94         for (i = 0; i < FRAG_BUFFER_SIZE; i++) {
  95                 tfp = kmalloc(sizeof(struct frag_packet_list_entry),
  96                         GFP_ATOMIC);
  97                 if (!tfp) {
  98                         frag_list_free(head);
  99                         return -ENOMEM;
 100                 }
 101                 tfp->skb = NULL;
 102                 tfp->seqno = 0;
 103                 INIT_LIST_HEAD(&tfp->list);
 104                 list_add(&tfp->list, head);
 105         }
 106
 107         return 0;
 108 }
 109
 110 static struct frag_packet_list_entry *frag_search_packet(struct list_head *head,
 111                                                  struct unicast_frag_packet *up)
 112 {
 113         struct frag_packet_list_entry *tfp;
 114         struct unicast_frag_packet *tmp_up = NULL;
 115         uint16_t search_seqno;
 116
 117         if (up->flags & UNI_FRAG_HEAD)
 118                 search_seqno = ntohs(up->seqno)+1;
 119         else
 120                 search_seqno = ntohs(up->seqno)-1;
 121
 122         list_for_each_entry(tfp, head, list) {
 123
 124                 if (!tfp->skb)
 125                         continue;
 126
 127                 if (tfp->seqno == ntohs(up->seqno))
 128                         goto mov_tail;
 129
 130                 tmp_up = (struct unicast_frag_packet *)tfp->skb->data;
 131
 132                 if (tfp->seqno == search_seqno) {
 133
 134                         if ((tmp_up->flags & UNI_FRAG_HEAD) !=
 135                             (up->flags & UNI_FRAG_HEAD))
 136                                 return tfp;
 137                         else
 138                                 goto mov_tail;
 139                 }
 140         }
 141         return NULL;
 142
 143 mov_tail:
 144         list_move_tail(&tfp->list, head);
 145         return NULL;
 146 }
 147
 148 void frag_list_free(struct list_head *head)
 149 {
 150         struct frag_packet_list_entry *pf, *tmp_pf;
 151
 152         if (!list_empty(head)) {
 153
 154                 list_for_each_entry_safe(pf, tmp_pf, head, list) {
 155                         kfree_skb(pf->skb);
 156                         list_del(&pf->list);
 157                         kfree(pf);
 158                 }
 159         }
 160         return;
 161 }
 162
 163 /* frag_reassemble_skb():
 164  * returns NET_RX_DROP if the operation failed - skb is left intact
 165  * returns NET_RX_SUCCESS if the fragment was buffered (skb_new will be NULL)
 166  * or the skb could be reassembled (skb_new will point to the new packet and
 167  * skb was freed)
 168  */
 169 int frag_reassemble_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
 170                         struct sk_buff **new_skb)
 171 {
 172         unsigned long flags;
 173         struct orig_node *orig_node;
 174         struct frag_packet_list_entry *tmp_frag_entry;
 175         int ret = NET_RX_DROP;
 176         struct unicast_frag_packet *unicast_packet =
 177                 (struct unicast_frag_packet *)skb->data;
 178
 179         *new_skb = NULL;
 180         spin_lock_irqsave(&bat_priv->orig_hash_lock, flags);
 181         orig_node = ((struct orig_node *)
 182                     hash_find(bat_priv->orig_hash, unicast_packet->orig));
 183
 184         if (!orig_node) {
 185                 pr_debug("couldn't find originator in orig_hash\n");
 186                 goto out;
 187         }
 188
 189         orig_node->last_frag_packet = jiffies;
 190
 191         if (list_empty(&orig_node->frag_list) &&
 192             frag_create_buffer(&orig_node->frag_list)) {
 193                 pr_debug("couldn't create frag buffer\n");
 194                 goto out;
 195         }
 196
 197         tmp_frag_entry = frag_search_packet(&orig_node->frag_list,
 198                                             unicast_packet);
 199
 200         if (!tmp_frag_entry) {
 201                 frag_create_entry(&orig_node->frag_list, skb);
 202                 ret = NET_RX_SUCCESS;
 203                 goto out;
 204         }
 205
 206         *new_skb = frag_merge_packet(&orig_node->frag_list, tmp_frag_entry,
 207                                      skb);
 208         /* if not, merge failed */
 209         if (*new_skb)
 210                 ret = NET_RX_SUCCESS;
 211 out:
 212         spin_unlock_irqrestore(&bat_priv->orig_hash_lock, flags);
 213
 214         return ret;
 215 }
 216
 217 int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
 218                   struct batman_if *batman_if, uint8_t dstaddr[])
 219 {
 220         struct unicast_packet tmp_uc, *unicast_packet;
 221         struct sk_buff *frag_skb;
 222         struct unicast_frag_packet *frag1, *frag2;
 223         int uc_hdr_len = sizeof(struct unicast_packet);
 224         int ucf_hdr_len = sizeof(struct unicast_frag_packet);
 225         int data_len = skb->len;
 226
 227         if (!bat_priv->primary_if)
 228                 goto dropped;
 229
 230         unicast_packet = (struct unicast_packet *) skb->data;
 231
 232         memcpy(&tmp_uc, unicast_packet, uc_hdr_len);
 233         frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len);
 234         skb_split(skb, frag_skb, data_len / 2);
 235
 236         if (my_skb_head_push(skb, ucf_hdr_len - uc_hdr_len) < 0 ||
 237             my_skb_head_push(frag_skb, ucf_hdr_len) < 0)
 238                 goto drop_frag;
 239
 240         frag1 = (struct unicast_frag_packet *)skb->data;
 241         frag2 = (struct unicast_frag_packet *)frag_skb->data;
 242
 243         memcpy(frag1, &tmp_uc, sizeof(struct unicast_packet));
 244
 245         frag1->ttl--;
 246         frag1->version = COMPAT_VERSION;
 247         frag1->packet_type = BAT_UNICAST_FRAG;
 248
 249         memcpy(frag1->orig, bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
 250         memcpy(frag2, frag1, sizeof(struct unicast_frag_packet));
 251
 252         frag1->flags |= UNI_FRAG_HEAD;
 253         frag2->flags &= ~UNI_FRAG_HEAD;
 254
 255         frag1->seqno = htons((uint16_t)atomic_inc_return(
 256                              &batman_if->frag_seqno));
 257         frag2->seqno = htons((uint16_t)atomic_inc_return(
 258                              &batman_if->frag_seqno));
 259
 260         send_skb_packet(skb, batman_if, dstaddr);
 261         send_skb_packet(frag_skb, batman_if, dstaddr);
 262         return NET_RX_SUCCESS;
 263
 264 drop_frag:
 265         kfree_skb(frag_skb);
 266 dropped:
 267         kfree_skb(skb);
 268         return NET_RX_DROP;
 269 }
 270
 271 int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv)
 272 {
 273         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
 274         struct unicast_packet *unicast_packet;
 275         struct orig_node *orig_node;
 276         struct batman_if *batman_if;
 277         struct neigh_node *router;
 278         int data_len = skb->len;
 279         uint8_t dstaddr[6];
 280         unsigned long flags;
 281
 282         spin_lock_irqsave(&bat_priv->orig_hash_lock, flags);
 283
 284         /* get routing information */
 285         orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash,
 286                                                    ethhdr->h_dest));
 287
 288         /* check for hna host */
 289         if (!orig_node)
 290                 orig_node = transtable_search(bat_priv, ethhdr->h_dest);
 291
 292         router = find_router(bat_priv, orig_node, NULL);
 293
 294         if (!router)
 295                 goto unlock;
 296
 297         /* don't lock while sending the packets ... we therefore
 298                 * copy the required data before sending */
 299
 300         batman_if = router->if_incoming;
 301         memcpy(dstaddr, router->addr, ETH_ALEN);
 302
 303         spin_unlock_irqrestore(&bat_priv->orig_hash_lock, flags);
 304
 305         if (batman_if->if_status != IF_ACTIVE)
 306                 goto dropped;
 307
 308         if (my_skb_head_push(skb, sizeof(struct unicast_packet)) < 0)
 309                 goto dropped;
 310
 311         unicast_packet = (struct unicast_packet *)skb->data;
 312
 313         unicast_packet->version = COMPAT_VERSION;
 314         /* batman packet type: unicast */
 315         unicast_packet->packet_type = BAT_UNICAST;
 316         /* set unicast ttl */
 317         unicast_packet->ttl = TTL;
 318         /* copy the destination for faster routing */
 319         memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN);
 320
 321         if (atomic_read(&bat_priv->fragmentation) &&
 322             data_len + sizeof(struct unicast_packet) >
 323             batman_if->net_dev->mtu) {
 324                 /* send frag skb decreases ttl */
 325                 unicast_packet->ttl++;
 326                 return frag_send_skb(skb, bat_priv, batman_if,
 327                                      dstaddr);
 328         }
 329         send_skb_packet(skb, batman_if, dstaddr);
 330         return 0;
 331
 332 unlock:
 333         spin_unlock_irqrestore(&bat_priv->orig_hash_lock, flags);
 334 dropped:
 335         kfree_skb(skb);
 336         return 1;
 337 }