net/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 "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             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         spin_lock_bh(&bat_priv->orig_hash_lock);
 187         orig_node = ((struct orig_node *)
 188                     hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
 189                               unicast_packet->orig));
 190
 191         if (!orig_node) {
 192                 pr_debug("couldn't find originator in orig_hash\n");
 193                 goto out;
 194         }
 195
 196         orig_node->last_frag_packet = jiffies;
 197
 198         if (list_empty(&orig_node->frag_list) &&
 199             frag_create_buffer(&orig_node->frag_list)) {
 200                 pr_debug("couldn't create frag buffer\n");
 201                 goto out;
 202         }
 203
 204         tmp_frag_entry = frag_search_packet(&orig_node->frag_list,
 205                                             unicast_packet);
 206
 207         if (!tmp_frag_entry) {
 208                 frag_create_entry(&orig_node->frag_list, skb);
 209                 ret = NET_RX_SUCCESS;
 210                 goto out;
 211         }
 212
 213         *new_skb = frag_merge_packet(&orig_node->frag_list, tmp_frag_entry,
 214                                      skb);
 215         /* if not, merge failed */
 216         if (*new_skb)
 217                 ret = NET_RX_SUCCESS;
 218 out:
 219         spin_unlock_bh(&bat_priv->orig_hash_lock);
 220
 221         return ret;
 222 }
 223
 224 int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
 225                   struct batman_if *batman_if, uint8_t dstaddr[])
 226 {
 227         struct unicast_packet tmp_uc, *unicast_packet;
 228         struct sk_buff *frag_skb;
 229         struct unicast_frag_packet *frag1, *frag2;
 230         int uc_hdr_len = sizeof(struct unicast_packet);
 231         int ucf_hdr_len = sizeof(struct unicast_frag_packet);
 232         int data_len = skb->len;
 233
 234         if (!bat_priv->primary_if)
 235                 goto dropped;
 236
 237         frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len);
 238         if (!frag_skb)
 239                 goto dropped;
 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);
 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(struct unicast_packet));
 253
 254         frag1->ttl--;
 255         frag1->version = COMPAT_VERSION;
 256         frag1->packet_type = BAT_UNICAST_FRAG;
 257
 258         memcpy(frag1->orig, bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
 259         memcpy(frag2, frag1, sizeof(struct unicast_frag_packet));
 260
 261         frag1->flags |= UNI_FRAG_HEAD;
 262         frag2->flags &= ~UNI_FRAG_HEAD;
 263
 264         frag1->seqno = htons((uint16_t)atomic_inc_return(
 265                              &batman_if->frag_seqno));
 266         frag2->seqno = htons((uint16_t)atomic_inc_return(
 267                              &batman_if->frag_seqno));
 268
 269         send_skb_packet(skb, batman_if, dstaddr);
 270         send_skb_packet(frag_skb, batman_if, dstaddr);
 271         return NET_RX_SUCCESS;
 272
 273 drop_frag:
 274         kfree_skb(frag_skb);
 275 dropped:
 276         kfree_skb(skb);
 277         return NET_RX_DROP;
 278 }
 279
 280 int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv)
 281 {
 282         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
 283         struct unicast_packet *unicast_packet;
 284         struct orig_node *orig_node;
 285         struct batman_if *batman_if;
 286         struct neigh_node *router;
 287         int data_len = skb->len;
 288         uint8_t dstaddr[6];
 289
 290         spin_lock_bh(&bat_priv->orig_hash_lock);
 291
 292         /* get routing information */
 293         if (is_multicast_ether_addr(ethhdr->h_dest))
 294                 orig_node = (struct orig_node *)gw_get_selected(bat_priv);
 295         else
 296                 orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash,
 297                                                            compare_orig,
 298                                                            choose_orig,
 299                                                            ethhdr->h_dest));
 300
 301         /* check for hna host */
 302         if (!orig_node)
 303                 orig_node = transtable_search(bat_priv, ethhdr->h_dest);
 304
 305         router = find_router(bat_priv, orig_node, NULL);
 306
 307         if (!router)
 308                 goto unlock;
 309
 310         /* don't lock while sending the packets ... we therefore
 311                 * copy the required data before sending */
 312
 313         batman_if = router->if_incoming;
 314         memcpy(dstaddr, router->addr, ETH_ALEN);
 315
 316         spin_unlock_bh(&bat_priv->orig_hash_lock);
 317
 318         if (batman_if->if_status != IF_ACTIVE)
 319                 goto dropped;
 320
 321         if (my_skb_head_push(skb, sizeof(struct unicast_packet)) < 0)
 322                 goto dropped;
 323
 324         unicast_packet = (struct unicast_packet *)skb->data;
 325
 326         unicast_packet->version = COMPAT_VERSION;
 327         /* batman packet type: unicast */
 328         unicast_packet->packet_type = BAT_UNICAST;
 329         /* set unicast ttl */
 330         unicast_packet->ttl = TTL;
 331         /* copy the destination for faster routing */
 332         memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN);
 333
 334         if (atomic_read(&bat_priv->fragmentation) &&
 335             data_len + sizeof(struct unicast_packet) >
 336             batman_if->net_dev->mtu) {
 337                 /* send frag skb decreases ttl */
 338                 unicast_packet->ttl++;
 339                 return frag_send_skb(skb, bat_priv, batman_if,
 340                                      dstaddr);
 341         }
 342         send_skb_packet(skb, batman_if, dstaddr);
 343         return 0;
 344
 345 unlock:
 346         spin_unlock_bh(&bat_priv->orig_hash_lock);
 347 dropped:
 348         kfree_skb(skb);
 349         return 1;
 350 }