Pileus Git - ~andy/linux/blob - 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         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
 182         orig_node = orig_hash_find(bat_priv, unicast_packet->orig);
 183         if (!orig_node)
 184                 goto out;
 185
 186         orig_node->last_frag_packet = jiffies;
 187
 188         if (list_empty(&orig_node->frag_list) &&
 189             frag_create_buffer(&orig_node->frag_list)) {
 190                 pr_debug("couldn't create frag buffer\n");
 191                 goto out;
 192         }
 193
 194         tmp_frag_entry = frag_search_packet(&orig_node->frag_list,
 195                                             unicast_packet);
 196
 197         if (!tmp_frag_entry) {
 198                 frag_create_entry(&orig_node->frag_list, skb);
 199                 ret = NET_RX_SUCCESS;
 200                 goto out;
 201         }
 202
 203         *new_skb = frag_merge_packet(&orig_node->frag_list, tmp_frag_entry,
 204                                      skb);
 205         /* if not, merge failed */
 206         if (*new_skb)
 207                 ret = NET_RX_SUCCESS;
 208
 209 out:
 210         if (orig_node)
 211                 orig_node_free_ref(orig_node);
 212         return ret;
 213 }
 214
 215 int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
 216                   struct batman_if *batman_if, uint8_t dstaddr[])
 217 {
 218         struct unicast_packet tmp_uc, *unicast_packet;
 219         struct sk_buff *frag_skb;
 220         struct unicast_frag_packet *frag1, *frag2;
 221         int uc_hdr_len = sizeof(struct unicast_packet);
 222         int ucf_hdr_len = sizeof(struct unicast_frag_packet);
 223         int data_len = skb->len - uc_hdr_len;
 224         int large_tail = 0;
 225         uint16_t seqno;
 226
 227         if (!bat_priv->primary_if)
 228                 goto dropped;
 229
 230         frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len);
 231         if (!frag_skb)
 232                 goto dropped;
 233         skb_reserve(frag_skb, ucf_hdr_len);
 234
 235         unicast_packet = (struct unicast_packet *) skb->data;
 236         memcpy(&tmp_uc, unicast_packet, uc_hdr_len);
 237         skb_split(skb, frag_skb, data_len / 2 + uc_hdr_len);
 238
 239         if (my_skb_head_push(skb, ucf_hdr_len - uc_hdr_len) < 0 ||
 240             my_skb_head_push(frag_skb, ucf_hdr_len) < 0)
 241                 goto drop_frag;
 242
 243         frag1 = (struct unicast_frag_packet *)skb->data;
 244         frag2 = (struct unicast_frag_packet *)frag_skb->data;
 245
 246         memcpy(frag1, &tmp_uc, sizeof(struct unicast_packet));
 247
 248         frag1->ttl--;
 249         frag1->version = COMPAT_VERSION;
 250         frag1->packet_type = BAT_UNICAST_FRAG;
 251
 252         memcpy(frag1->orig, bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
 253         memcpy(frag2, frag1, sizeof(struct unicast_frag_packet));
 254
 255         if (data_len & 1)
 256                 large_tail = UNI_FRAG_LARGETAIL;
 257
 258         frag1->flags = UNI_FRAG_HEAD | large_tail;
 259         frag2->flags = large_tail;
 260
 261         seqno = atomic_add_return(2, &batman_if->frag_seqno);
 262         frag1->seqno = htons(seqno - 1);
 263         frag2->seqno = htons(seqno);
 264
 265         send_skb_packet(skb, batman_if, dstaddr);
 266         send_skb_packet(frag_skb, batman_if, dstaddr);
 267         return NET_RX_SUCCESS;
 268
 269 drop_frag:
 270         kfree_skb(frag_skb);
 271 dropped:
 272         kfree_skb(skb);
 273         return NET_RX_DROP;
 274 }
 275
 276 int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv)
 277 {
 278         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
 279         struct unicast_packet *unicast_packet;
 280         struct orig_node *orig_node;
 281         struct neigh_node *neigh_node;
 282         int data_len = skb->len;
 283         int ret = 1;
 284
 285         /* get routing information */
 286         if (is_multicast_ether_addr(ethhdr->h_dest)) {
 287                 orig_node = (struct orig_node *)gw_get_selected(bat_priv);
 288                 if (orig_node)
 289                         goto find_router;
 290         }
 291
 292         /* check for hna host - increases orig_node refcount */
 293         orig_node = transtable_search(bat_priv, ethhdr->h_dest);
 294
 295 find_router:
 296         /**
 297          * find_router():
 298          *  - if orig_node is NULL it returns NULL
 299          *  - increases neigh_nodes refcount if found.
 300          */
 301         neigh_node = find_router(bat_priv, orig_node, NULL);
 302
 303         if (!neigh_node)
 304                 goto out;
 305
 306         if (neigh_node->if_incoming->if_status != IF_ACTIVE)
 307                 goto out;
 308
 309         if (my_skb_head_push(skb, sizeof(struct unicast_packet)) < 0)
 310                 goto out;
 311
 312         unicast_packet = (struct unicast_packet *)skb->data;
 313
 314         unicast_packet->version = COMPAT_VERSION;
 315         /* batman packet type: unicast */
 316         unicast_packet->packet_type = BAT_UNICAST;
 317         /* set unicast ttl */
 318         unicast_packet->ttl = TTL;
 319         /* copy the destination for faster routing */
 320         memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN);
 321
 322         if (atomic_read(&bat_priv->fragmentation) &&
 323             data_len + sizeof(struct unicast_packet) >
 324                                 neigh_node->if_incoming->net_dev->mtu) {
 325                 /* send frag skb decreases ttl */
 326                 unicast_packet->ttl++;
 327                 ret = frag_send_skb(skb, bat_priv,
 328                                     neigh_node->if_incoming, neigh_node->addr);
 329                 goto out;
 330         }
 331
 332         send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
 333         ret = 0;
 334         goto out;
 335
 336 out:
 337         if (neigh_node)
 338                 neigh_node_free_ref(neigh_node);
 339         if (orig_node)
 340                 orig_node_free_ref(orig_node);
 341         if (ret == 1)
 342                 kfree_skb(skb);
 343         return ret;
 344 }