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 struct sk_buff *merge_frag_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 void create_frag_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 void create_frag_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                 tfp->skb = NULL;
  90                 tfp->seqno = 0;
  91                 INIT_LIST_HEAD(&tfp->list);
  92                 list_add(&tfp->list, head);
  93         }
  94
  95         return;
  96 }
  97
  98 struct frag_packet_list_entry *search_frag_packet(struct list_head *head,
  99                                                  struct unicast_frag_packet *up)
 100 {
 101         struct frag_packet_list_entry *tfp;
 102         struct unicast_frag_packet *tmp_up = NULL;
 103         uint16_t search_seqno;
 104
 105         if (up->flags & UNI_FRAG_HEAD)
 106                 search_seqno = ntohs(up->seqno)+1;
 107         else
 108                 search_seqno = ntohs(up->seqno)-1;
 109
 110         list_for_each_entry(tfp, head, list) {
 111
 112                 if (!tfp->skb)
 113                         continue;
 114
 115                 if (tfp->seqno == ntohs(up->seqno))
 116                         goto mov_tail;
 117
 118                 tmp_up = (struct unicast_frag_packet *)tfp->skb->data;
 119
 120                 if (tfp->seqno == search_seqno) {
 121
 122                         if ((tmp_up->flags & UNI_FRAG_HEAD) !=
 123                             (up->flags & UNI_FRAG_HEAD))
 124                                 return tfp;
 125                         else
 126                                 goto mov_tail;
 127                 }
 128         }
 129         return NULL;
 130
 131 mov_tail:
 132         list_move_tail(&tfp->list, head);
 133         return NULL;
 134 }
 135
 136 void frag_list_free(struct list_head *head)
 137 {
 138         struct frag_packet_list_entry *pf, *tmp_pf;
 139
 140         if (!list_empty(head)) {
 141
 142                 list_for_each_entry_safe(pf, tmp_pf, head, list) {
 143                         kfree_skb(pf->skb);
 144                         list_del(&pf->list);
 145                         kfree(pf);
 146                 }
 147         }
 148         return;
 149 }
 150
 151 static int unicast_send_frag_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
 152                           struct batman_if *batman_if, uint8_t dstaddr[],
 153                           struct orig_node *orig_node)
 154 {
 155         struct unicast_frag_packet *ucast_frag1, *ucast_frag2;
 156         int hdr_len = sizeof(struct unicast_frag_packet);
 157         struct sk_buff *frag_skb;
 158         int data_len = skb->len;
 159
 160         if (!bat_priv->primary_if)
 161                 goto dropped;
 162
 163         frag_skb = dev_alloc_skb(data_len - (data_len / 2) + hdr_len);
 164         skb_split(skb, frag_skb, data_len / 2);
 165
 166         if (my_skb_head_push(frag_skb, hdr_len) < 0 ||
 167             my_skb_head_push(skb, hdr_len) < 0)
 168                 goto drop_frag;
 169
 170         ucast_frag1 = (struct unicast_frag_packet *)skb->data;
 171         ucast_frag2 = (struct unicast_frag_packet *)frag_skb->data;
 172
 173         ucast_frag1->version = COMPAT_VERSION;
 174         ucast_frag1->packet_type = BAT_UNICAST_FRAG;
 175         ucast_frag1->ttl = TTL;
 176         memcpy(ucast_frag1->orig,
 177                bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
 178         memcpy(ucast_frag1->dest, orig_node->orig, ETH_ALEN);
 179
 180         memcpy(ucast_frag2, ucast_frag1, sizeof(struct unicast_frag_packet));
 181
 182         ucast_frag1->flags |= UNI_FRAG_HEAD;
 183         ucast_frag2->flags &= ~UNI_FRAG_HEAD;
 184
 185         ucast_frag1->seqno = htons((uint16_t)atomic_inc_return(
 186                                                 &batman_if->frag_seqno));
 187
 188         ucast_frag2->seqno = htons((uint16_t)atomic_inc_return(
 189                                                 &batman_if->frag_seqno));
 190
 191         send_skb_packet(skb, batman_if, dstaddr);
 192         send_skb_packet(frag_skb, batman_if, dstaddr);
 193         return 0;
 194
 195 drop_frag:
 196         kfree_skb(frag_skb);
 197 dropped:
 198         kfree_skb(skb);
 199         return 1;
 200 }
 201
 202 int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv)
 203 {
 204         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
 205         struct unicast_packet *unicast_packet;
 206         struct orig_node *orig_node;
 207         struct batman_if *batman_if;
 208         struct neigh_node *router;
 209         int data_len = skb->len;
 210         uint8_t dstaddr[6];
 211         unsigned long flags;
 212
 213         spin_lock_irqsave(&bat_priv->orig_hash_lock, flags);
 214
 215         /* get routing information */
 216         orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash,
 217                                                    ethhdr->h_dest));
 218
 219         /* check for hna host */
 220         if (!orig_node)
 221                 orig_node = transtable_search(bat_priv, ethhdr->h_dest);
 222
 223         router = find_router(orig_node, NULL);
 224
 225         if (!router)
 226                 goto unlock;
 227
 228         /* don't lock while sending the packets ... we therefore
 229                 * copy the required data before sending */
 230
 231         batman_if = router->if_incoming;
 232         memcpy(dstaddr, router->addr, ETH_ALEN);
 233
 234         spin_unlock_irqrestore(&bat_priv->orig_hash_lock, flags);
 235
 236         if (batman_if->if_status != IF_ACTIVE)
 237                 goto dropped;
 238
 239         if (atomic_read(&bat_priv->frag_enabled) &&
 240             data_len + sizeof(struct unicast_packet) > batman_if->net_dev->mtu)
 241                 return unicast_send_frag_skb(skb, bat_priv, batman_if,
 242                                              dstaddr, orig_node);
 243
 244         if (my_skb_head_push(skb, sizeof(struct unicast_packet)) < 0)
 245                 goto dropped;
 246
 247         unicast_packet = (struct unicast_packet *)skb->data;
 248
 249         unicast_packet->version = COMPAT_VERSION;
 250         /* batman packet type: unicast */
 251         unicast_packet->packet_type = BAT_UNICAST;
 252         /* set unicast ttl */
 253         unicast_packet->ttl = TTL;
 254         /* copy the destination for faster routing */
 255         memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN);
 256
 257         send_skb_packet(skb, batman_if, dstaddr);
 258         return 0;
 259
 260 unlock:
 261         spin_unlock_irqrestore(&bat_priv->orig_hash_lock, flags);
 262 dropped:
 263         kfree_skb(skb);
 264         return 1;
 265 }