unicast.c revision fb778ea173fcd58b8fc3d75c674f07fab187b55f
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 34static 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 75static 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 91static 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 112static 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 145mov_tail: 146 list_move_tail(&tfp->list, head); 147 return NULL; 148} 149 150void 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 */ 171int 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 rcu_read_lock(); 183 orig_node = ((struct orig_node *) 184 hash_find(bat_priv->orig_hash, compare_orig, choose_orig, 185 unicast_packet->orig)); 186 rcu_read_unlock(); 187 188 if (!orig_node) { 189 pr_debug("couldn't find originator in orig_hash\n"); 190 goto out; 191 } 192 193 orig_node->last_frag_packet = jiffies; 194 195 if (list_empty(&orig_node->frag_list) && 196 frag_create_buffer(&orig_node->frag_list)) { 197 pr_debug("couldn't create frag buffer\n"); 198 goto out; 199 } 200 201 tmp_frag_entry = frag_search_packet(&orig_node->frag_list, 202 unicast_packet); 203 204 if (!tmp_frag_entry) { 205 frag_create_entry(&orig_node->frag_list, skb); 206 ret = NET_RX_SUCCESS; 207 goto out; 208 } 209 210 *new_skb = frag_merge_packet(&orig_node->frag_list, tmp_frag_entry, 211 skb); 212 /* if not, merge failed */ 213 if (*new_skb) 214 ret = NET_RX_SUCCESS; 215out: 216 spin_unlock_bh(&bat_priv->orig_hash_lock); 217 218 return ret; 219} 220 221int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv, 222 struct batman_if *batman_if, uint8_t dstaddr[]) 223{ 224 struct unicast_packet tmp_uc, *unicast_packet; 225 struct sk_buff *frag_skb; 226 struct unicast_frag_packet *frag1, *frag2; 227 int uc_hdr_len = sizeof(struct unicast_packet); 228 int ucf_hdr_len = sizeof(struct unicast_frag_packet); 229 int data_len = skb->len - uc_hdr_len; 230 int large_tail = 0; 231 uint16_t seqno; 232 233 if (!bat_priv->primary_if) 234 goto dropped; 235 236 frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len); 237 if (!frag_skb) 238 goto dropped; 239 skb_reserve(frag_skb, ucf_hdr_len); 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 + uc_hdr_len); 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 if (data_len & 1) 262 large_tail = UNI_FRAG_LARGETAIL; 263 264 frag1->flags = UNI_FRAG_HEAD | large_tail; 265 frag2->flags = large_tail; 266 267 seqno = atomic_add_return(2, &batman_if->frag_seqno); 268 frag1->seqno = htons(seqno - 1); 269 frag2->seqno = htons(seqno); 270 271 send_skb_packet(skb, batman_if, dstaddr); 272 send_skb_packet(frag_skb, batman_if, dstaddr); 273 return NET_RX_SUCCESS; 274 275drop_frag: 276 kfree_skb(frag_skb); 277dropped: 278 kfree_skb(skb); 279 return NET_RX_DROP; 280} 281 282int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv) 283{ 284 struct ethhdr *ethhdr = (struct ethhdr *)skb->data; 285 struct unicast_packet *unicast_packet; 286 struct orig_node *orig_node = NULL; 287 struct batman_if *batman_if; 288 struct neigh_node *router; 289 int data_len = skb->len; 290 uint8_t dstaddr[6]; 291 292 spin_lock_bh(&bat_priv->orig_hash_lock); 293 294 /* get routing information */ 295 if (is_multicast_ether_addr(ethhdr->h_dest)) 296 orig_node = (struct orig_node *)gw_get_selected(bat_priv); 297 298 /* check for hna host */ 299 if (!orig_node) 300 orig_node = transtable_search(bat_priv, ethhdr->h_dest); 301 302 router = find_router(bat_priv, orig_node, NULL); 303 304 if (!router) 305 goto unlock; 306 307 /* don't lock while sending the packets ... we therefore 308 * copy the required data before sending */ 309 310 batman_if = router->if_incoming; 311 memcpy(dstaddr, router->addr, ETH_ALEN); 312 313 spin_unlock_bh(&bat_priv->orig_hash_lock); 314 315 if (batman_if->if_status != IF_ACTIVE) 316 goto dropped; 317 318 if (my_skb_head_push(skb, sizeof(struct unicast_packet)) < 0) 319 goto dropped; 320 321 unicast_packet = (struct unicast_packet *)skb->data; 322 323 unicast_packet->version = COMPAT_VERSION; 324 /* batman packet type: unicast */ 325 unicast_packet->packet_type = BAT_UNICAST; 326 /* set unicast ttl */ 327 unicast_packet->ttl = TTL; 328 /* copy the destination for faster routing */ 329 memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN); 330 331 if (atomic_read(&bat_priv->fragmentation) && 332 data_len + sizeof(struct unicast_packet) > 333 batman_if->net_dev->mtu) { 334 /* send frag skb decreases ttl */ 335 unicast_packet->ttl++; 336 return frag_send_skb(skb, bat_priv, batman_if, 337 dstaddr); 338 } 339 send_skb_packet(skb, batman_if, dstaddr); 340 return 0; 341 342unlock: 343 spin_unlock_bh(&bat_priv->orig_hash_lock); 344dropped: 345 kfree_skb(skb); 346 return 1; 347} 348