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         skb_pull(tmp_skb, sizeof(struct unicast_frag_packet));
  54         if (pskb_expand_head(skb, 0, tmp_skb->len, GFP_ATOMIC) < 0) {
  55                 /* free buffered skb, skb will be freed later */
  56                 kfree_skb(tfp->skb);
  57                 return NULL;
  58         }
  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
  75 static void frag_create_entry(struct list_head *head, struct sk_buff *skb)
  76 {
  77         struct frag_packet_list_entry *tfp;
  78         struct unicast_frag_packet *up =
  79                 (struct unicast_frag_packet *)skb->data;
  80
  81         /* free and oldest packets stand at the end */
  82         tfp = list_entry((head)->prev, typeof(*tfp), list);
  83         kfree_skb(tfp->skb);
  84
  85         tfp->seqno = ntohs(up->seqno);
  86         tfp->skb = skb;
  87         list_move(&tfp->list, head);
  88         return;
  89 }
  90
  91 static int frag_create_buffer(struct list_head *head)
  92 {
  93         int i;
  94         struct frag_packet_list_entry *tfp;
  95
  96         for (i = 0; i < FRAG_BUFFER_SIZE; i++) {
  97                 tfp = kmalloc(sizeof(struct frag_packet_list_entry),
  98                         GFP_ATOMIC);
  99                 if (!tfp) {
 100                         frag_list_free(head);
 101                         return -ENOMEM;
 102                 }
 103                 tfp->skb = NULL;
 104                 tfp->seqno = 0;
 105                 INIT_LIST_HEAD(&tfp->list);
 106                 list_add(&tfp->list, head);
 107         }
 108
 109         return 0;
 110 }
 111
 112 static struct frag_packet_list_entry *frag_search_packet(struct list_head *head,
 113                                                  struct unicast_frag_packet *up)
 114 {
 115         struct frag_packet_list_entry *tfp;
 116         struct unicast_frag_packet *tmp_up = NULL;
 117         uint16_t search_seqno;
 118
 119         if (up->flags & UNI_FRAG_HEAD)
 120                 search_seqno = ntohs(up->seqno)+1;
 121         else
 122                 search_seqno = ntohs(up->seqno)-1;
 123
 124         list_for_each_entry(tfp, head, list) {
 125
 126                 if (!tfp->skb)
 127                         continue;
 128
 129                 if (tfp->seqno == ntohs(up->seqno))
 130                         goto mov_tail;
 131
 132                 tmp_up = (struct unicast_frag_packet *)tfp->skb->data;
 133
 134                 if (tfp->seqno == search_seqno) {
 135
 136                         if ((tmp_up->flags & UNI_FRAG_HEAD) !=
 137                             (up->flags & UNI_FRAG_HEAD))
 138                                 return tfp;
 139                         else
 140                                 goto mov_tail;
 141                 }
 142         }
 143         return NULL;
 144
 145 mov_tail:
 146         list_move_tail(&tfp->list, head);
 147         return NULL;
 148 }
 149
 150 void frag_list_free(struct list_head *head)
 151 {
 152         struct frag_packet_list_entry *pf, *tmp_pf;
 153
 154         if (!list_empty(head)) {
 155
 156                 list_for_each_entry_safe(pf, tmp_pf, head, list) {
 157                         kfree_skb(pf->skb);
 158                         list_del(&pf->list);
 159                         kfree(pf);
 160                 }
 161         }
 162         return;
 163 }
 164
 165 /* frag_reassemble_skb():
 166  * returns NET_RX_DROP if the operation failed - skb is left intact
 167  * returns NET_RX_SUCCESS if the fragment was buffered (skb_new will be NULL)
 168  * or the skb could be reassembled (skb_new will point to the new packet and
 169  * skb was freed)
 170  */
 171 int frag_reassemble_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
 172                         struct sk_buff **new_skb)
 173 {
 174         struct orig_node *orig_node;
 175         struct frag_packet_list_entry *tmp_frag_entry;
 176         int ret = NET_RX_DROP;
 177         struct unicast_frag_packet *unicast_packet =
 178                 (struct unicast_frag_packet *)skb->data;
 179
 180         *new_skb = NULL;
 181         spin_lock_bh(&bat_priv->orig_hash_lock);
 182         orig_node = ((struct orig_node *)
 183                     hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
 184                               unicast_packet->orig));
 185
 186         if (!orig_node) {
 187                 pr_debug("couldn't find originator in orig_hash\n");
 188                 goto out;
 189         }
 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 out:
 214         spin_unlock_bh(&bat_priv->orig_hash_lock);
 215
 216         return ret;
 217 }
 218
 219 int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
 220                   struct batman_if *batman_if, uint8_t dstaddr[])
 221 {
 222         struct unicast_packet tmp_uc, *unicast_packet;
 223         struct sk_buff *frag_skb;
 224         struct unicast_frag_packet *frag1, *frag2;
 225         int uc_hdr_len = sizeof(struct unicast_packet);
 226         int ucf_hdr_len = sizeof(struct unicast_frag_packet);
 227         int data_len = skb->len;
 228
 229         if (!bat_priv->primary_if)
 230                 goto dropped;
 231
 232         frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len);
 233         if (!frag_skb)
 234                 goto dropped;
 235
 236         unicast_packet = (struct unicast_packet *) skb->data;
 237         memcpy(&tmp_uc, unicast_packet, uc_hdr_len);
 238         skb_split(skb, frag_skb, data_len / 2);
 239
 240         if (my_skb_head_push(skb, ucf_hdr_len - uc_hdr_len) < 0 ||
 241             my_skb_head_push(frag_skb, ucf_hdr_len) < 0)
 242                 goto drop_frag;
 243
 244         frag1 = (struct unicast_frag_packet *)skb->data;
 245         frag2 = (struct unicast_frag_packet *)frag_skb->data;
 246
 247         memcpy(frag1, &tmp_uc, sizeof(struct unicast_packet));
 248
 249         frag1->ttl--;
 250         frag1->version = COMPAT_VERSION;
 251         frag1->packet_type = BAT_UNICAST_FRAG;
 252
 253         memcpy(frag1->orig, bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
 254         memcpy(frag2, frag1, sizeof(struct unicast_frag_packet));
 255
 256         frag1->flags |= UNI_FRAG_HEAD;
 257         frag2->flags &= ~UNI_FRAG_HEAD;
 258
 259         frag1->seqno = htons((uint16_t)atomic_inc_return(
 260                              &batman_if->frag_seqno));
 261         frag2->seqno = htons((uint16_t)atomic_inc_return(
 262                              &batman_if->frag_seqno));
 263
 264         send_skb_packet(skb, batman_if, dstaddr);
 265         send_skb_packet(frag_skb, batman_if, dstaddr);
 266         return NET_RX_SUCCESS;
 267
 268 drop_frag:
 269         kfree_skb(frag_skb);
 270 dropped:
 271         kfree_skb(skb);
 272         return NET_RX_DROP;
 273 }
 274
 275 int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv)
 276 {
 277         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
 278         struct unicast_packet *unicast_packet;
 279         struct orig_node *orig_node;
 280         struct batman_if *batman_if;
 281         struct neigh_node *router;
 282         int data_len = skb->len;
 283         uint8_t dstaddr[6];
 284
 285         spin_lock_bh(&bat_priv->orig_hash_lock);
 286
 287         /* get routing information */
 288         if (is_multicast_ether_addr(ethhdr->h_dest))
 289                 orig_node = (struct orig_node *)gw_get_selected(bat_priv);
 290         else
 291                 orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash,
 292                                                            compare_orig,
 293                                                            choose_orig,
 294                                                            ethhdr->h_dest));
 295
 296         /* check for hna host */
 297         if (!orig_node)
 298                 orig_node = transtable_search(bat_priv, ethhdr->h_dest);
 299
 300         router = find_router(bat_priv, orig_node, NULL);
 301
 302         if (!router)
 303                 goto unlock;
 304
 305         /* don't lock while sending the packets ... we therefore
 306                 * copy the required data before sending */
 307
 308         batman_if = router->if_incoming;
 309         memcpy(dstaddr, router->addr, ETH_ALEN);
 310
 311         spin_unlock_bh(&bat_priv->orig_hash_lock);
 312
 313         if (batman_if->if_status != IF_ACTIVE)
 314                 goto dropped;
 315
 316         if (my_skb_head_push(skb, sizeof(struct unicast_packet)) < 0)
 317                 goto dropped;
 318
 319         unicast_packet = (struct unicast_packet *)skb->data;
 320
 321         unicast_packet->version = COMPAT_VERSION;
 322         /* batman packet type: unicast */
 323         unicast_packet->packet_type = BAT_UNICAST;
 324         /* set unicast ttl */
 325         unicast_packet->ttl = TTL;
 326         /* copy the destination for faster routing */
 327         memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN);
 328
 329         if (atomic_read(&bat_priv->fragmentation) &&
 330             data_len + sizeof(struct unicast_packet) >
 331             batman_if->net_dev->mtu) {
 332                 /* send frag skb decreases ttl */
 333                 unicast_packet->ttl++;
 334                 return frag_send_skb(skb, bat_priv, batman_if,
 335                                      dstaddr);
 336         }
 337         send_skb_packet(skb, batman_if, dstaddr);
 338         return 0;
 339
 340 unlock:
 341         spin_unlock_bh(&bat_priv->orig_hash_lock);
 342 dropped:
 343         kfree_skb(skb);
 344         return 1;
 345 }