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