unicast.c revision bbb1f90efba89b31fc5e329d5fcaf10aca99212b
1/* Copyright (C) 2010-2012 B.A.T.M.A.N. contributors: 2 * 3 * Andreas Langer 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of version 2 of the GNU General Public 7 * License as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it will be useful, but 10 * WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 17 * 02110-1301, USA 18 */ 19 20#include "main.h" 21#include "unicast.h" 22#include "send.h" 23#include "soft-interface.h" 24#include "gateway_client.h" 25#include "originator.h" 26#include "hash.h" 27#include "translation-table.h" 28#include "routing.h" 29#include "hard-interface.h" 30 31 32static struct sk_buff * 33batadv_frag_merge_packet(struct list_head *head, 34 struct batadv_frag_packet_list_entry *tfp, 35 struct sk_buff *skb) 36{ 37 struct batadv_unicast_frag_packet *up; 38 struct sk_buff *tmp_skb; 39 struct batadv_unicast_packet *unicast_packet; 40 int hdr_len = sizeof(*unicast_packet); 41 int uni_diff = sizeof(*up) - hdr_len; 42 43 up = (struct batadv_unicast_frag_packet *)skb->data; 44 /* set skb to the first part and tmp_skb to the second part */ 45 if (up->flags & BATADV_UNI_FRAG_HEAD) { 46 tmp_skb = tfp->skb; 47 } else { 48 tmp_skb = skb; 49 skb = tfp->skb; 50 } 51 52 if (skb_linearize(skb) < 0 || skb_linearize(tmp_skb) < 0) 53 goto err; 54 55 skb_pull(tmp_skb, sizeof(*up)); 56 if (pskb_expand_head(skb, 0, tmp_skb->len, GFP_ATOMIC) < 0) 57 goto err; 58 59 /* move free entry to end */ 60 tfp->skb = NULL; 61 tfp->seqno = 0; 62 list_move_tail(&tfp->list, head); 63 64 memcpy(skb_put(skb, tmp_skb->len), tmp_skb->data, tmp_skb->len); 65 kfree_skb(tmp_skb); 66 67 memmove(skb->data + uni_diff, skb->data, hdr_len); 68 unicast_packet = (struct batadv_unicast_packet *)skb_pull(skb, 69 uni_diff); 70 unicast_packet->header.packet_type = BATADV_UNICAST; 71 72 return skb; 73 74err: 75 /* free buffered skb, skb will be freed later */ 76 kfree_skb(tfp->skb); 77 return NULL; 78} 79 80static void batadv_frag_create_entry(struct list_head *head, 81 struct sk_buff *skb) 82{ 83 struct batadv_frag_packet_list_entry *tfp; 84 struct batadv_unicast_frag_packet *up; 85 86 up = (struct batadv_unicast_frag_packet *)skb->data; 87 88 /* free and oldest packets stand at the end */ 89 tfp = list_entry((head)->prev, typeof(*tfp), list); 90 kfree_skb(tfp->skb); 91 92 tfp->seqno = ntohs(up->seqno); 93 tfp->skb = skb; 94 list_move(&tfp->list, head); 95 return; 96} 97 98static int batadv_frag_create_buffer(struct list_head *head) 99{ 100 int i; 101 struct batadv_frag_packet_list_entry *tfp; 102 103 for (i = 0; i < BATADV_FRAG_BUFFER_SIZE; i++) { 104 tfp = kmalloc(sizeof(*tfp), GFP_ATOMIC); 105 if (!tfp) { 106 batadv_frag_list_free(head); 107 return -ENOMEM; 108 } 109 tfp->skb = NULL; 110 tfp->seqno = 0; 111 INIT_LIST_HEAD(&tfp->list); 112 list_add(&tfp->list, head); 113 } 114 115 return 0; 116} 117 118static struct batadv_frag_packet_list_entry * 119batadv_frag_search_packet(struct list_head *head, 120 const struct batadv_unicast_frag_packet *up) 121{ 122 struct batadv_frag_packet_list_entry *tfp; 123 struct batadv_unicast_frag_packet *tmp_up = NULL; 124 int is_head_tmp, is_head; 125 uint16_t search_seqno; 126 127 if (up->flags & BATADV_UNI_FRAG_HEAD) 128 search_seqno = ntohs(up->seqno)+1; 129 else 130 search_seqno = ntohs(up->seqno)-1; 131 132 is_head = !!(up->flags & BATADV_UNI_FRAG_HEAD); 133 134 list_for_each_entry(tfp, head, list) { 135 136 if (!tfp->skb) 137 continue; 138 139 if (tfp->seqno == ntohs(up->seqno)) 140 goto mov_tail; 141 142 tmp_up = (struct batadv_unicast_frag_packet *)tfp->skb->data; 143 144 if (tfp->seqno == search_seqno) { 145 is_head_tmp = !!(tmp_up->flags & BATADV_UNI_FRAG_HEAD); 146 if (is_head_tmp != is_head) 147 return tfp; 148 else 149 goto mov_tail; 150 } 151 } 152 return NULL; 153 154mov_tail: 155 list_move_tail(&tfp->list, head); 156 return NULL; 157} 158 159void batadv_frag_list_free(struct list_head *head) 160{ 161 struct batadv_frag_packet_list_entry *pf, *tmp_pf; 162 163 if (!list_empty(head)) { 164 165 list_for_each_entry_safe(pf, tmp_pf, head, list) { 166 kfree_skb(pf->skb); 167 list_del(&pf->list); 168 kfree(pf); 169 } 170 } 171 return; 172} 173 174/* frag_reassemble_skb(): 175 * returns NET_RX_DROP if the operation failed - skb is left intact 176 * returns NET_RX_SUCCESS if the fragment was buffered (skb_new will be NULL) 177 * or the skb could be reassembled (skb_new will point to the new packet and 178 * skb was freed) 179 */ 180int batadv_frag_reassemble_skb(struct sk_buff *skb, 181 struct batadv_priv *bat_priv, 182 struct sk_buff **new_skb) 183{ 184 struct batadv_orig_node *orig_node; 185 struct batadv_frag_packet_list_entry *tmp_frag_entry; 186 int ret = NET_RX_DROP; 187 struct batadv_unicast_frag_packet *unicast_packet; 188 189 unicast_packet = (struct batadv_unicast_frag_packet *)skb->data; 190 *new_skb = NULL; 191 192 orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->orig); 193 if (!orig_node) 194 goto out; 195 196 orig_node->last_frag_packet = jiffies; 197 198 if (list_empty(&orig_node->frag_list) && 199 batadv_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 = batadv_frag_search_packet(&orig_node->frag_list, 205 unicast_packet); 206 207 if (!tmp_frag_entry) { 208 batadv_frag_create_entry(&orig_node->frag_list, skb); 209 ret = NET_RX_SUCCESS; 210 goto out; 211 } 212 213 *new_skb = batadv_frag_merge_packet(&orig_node->frag_list, 214 tmp_frag_entry, skb); 215 /* if not, merge failed */ 216 if (*new_skb) 217 ret = NET_RX_SUCCESS; 218 219out: 220 if (orig_node) 221 batadv_orig_node_free_ref(orig_node); 222 return ret; 223} 224 225int batadv_frag_send_skb(struct sk_buff *skb, struct batadv_priv *bat_priv, 226 struct batadv_hard_iface *hard_iface, 227 const uint8_t dstaddr[]) 228{ 229 struct batadv_unicast_packet tmp_uc, *unicast_packet; 230 struct batadv_hard_iface *primary_if; 231 struct sk_buff *frag_skb; 232 struct batadv_unicast_frag_packet *frag1, *frag2; 233 int uc_hdr_len = sizeof(*unicast_packet); 234 int ucf_hdr_len = sizeof(*frag1); 235 int data_len = skb->len - uc_hdr_len; 236 int large_tail = 0, ret = NET_RX_DROP; 237 uint16_t seqno; 238 239 primary_if = batadv_primary_if_get_selected(bat_priv); 240 if (!primary_if) 241 goto dropped; 242 243 frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len); 244 if (!frag_skb) 245 goto dropped; 246 skb_reserve(frag_skb, ucf_hdr_len); 247 248 unicast_packet = (struct batadv_unicast_packet *)skb->data; 249 memcpy(&tmp_uc, unicast_packet, uc_hdr_len); 250 skb_split(skb, frag_skb, data_len / 2 + uc_hdr_len); 251 252 if (batadv_skb_head_push(skb, ucf_hdr_len - uc_hdr_len) < 0 || 253 batadv_skb_head_push(frag_skb, ucf_hdr_len) < 0) 254 goto drop_frag; 255 256 frag1 = (struct batadv_unicast_frag_packet *)skb->data; 257 frag2 = (struct batadv_unicast_frag_packet *)frag_skb->data; 258 259 memcpy(frag1, &tmp_uc, sizeof(tmp_uc)); 260 261 frag1->header.ttl--; 262 frag1->header.version = BATADV_COMPAT_VERSION; 263 frag1->header.packet_type = BATADV_UNICAST_FRAG; 264 265 memcpy(frag1->orig, primary_if->net_dev->dev_addr, ETH_ALEN); 266 memcpy(frag2, frag1, sizeof(*frag2)); 267 268 if (data_len & 1) 269 large_tail = BATADV_UNI_FRAG_LARGETAIL; 270 271 frag1->flags = BATADV_UNI_FRAG_HEAD | large_tail; 272 frag2->flags = large_tail; 273 274 seqno = atomic_add_return(2, &hard_iface->frag_seqno); 275 frag1->seqno = htons(seqno - 1); 276 frag2->seqno = htons(seqno); 277 278 batadv_send_skb_packet(skb, hard_iface, dstaddr); 279 batadv_send_skb_packet(frag_skb, hard_iface, dstaddr); 280 ret = NET_RX_SUCCESS; 281 goto out; 282 283drop_frag: 284 kfree_skb(frag_skb); 285dropped: 286 kfree_skb(skb); 287out: 288 if (primary_if) 289 batadv_hardif_free_ref(primary_if); 290 return ret; 291} 292 293int batadv_unicast_send_skb(struct sk_buff *skb, struct batadv_priv *bat_priv) 294{ 295 struct ethhdr *ethhdr = (struct ethhdr *)skb->data; 296 struct batadv_unicast_packet *unicast_packet; 297 struct batadv_orig_node *orig_node; 298 struct batadv_neigh_node *neigh_node; 299 int data_len = skb->len; 300 int ret = 1; 301 unsigned int dev_mtu; 302 303 /* get routing information */ 304 if (is_multicast_ether_addr(ethhdr->h_dest)) { 305 orig_node = batadv_gw_get_selected_orig(bat_priv); 306 if (orig_node) 307 goto find_router; 308 } 309 310 /* check for tt host - increases orig_node refcount. 311 * returns NULL in case of AP isolation 312 */ 313 orig_node = batadv_transtable_search(bat_priv, ethhdr->h_source, 314 ethhdr->h_dest); 315 316find_router: 317 /* find_router(): 318 * - if orig_node is NULL it returns NULL 319 * - increases neigh_nodes refcount if found. 320 */ 321 neigh_node = batadv_find_router(bat_priv, orig_node, NULL); 322 323 if (!neigh_node) 324 goto out; 325 326 if (batadv_skb_head_push(skb, sizeof(*unicast_packet)) < 0) 327 goto out; 328 329 unicast_packet = (struct batadv_unicast_packet *)skb->data; 330 331 unicast_packet->header.version = BATADV_COMPAT_VERSION; 332 /* batman packet type: unicast */ 333 unicast_packet->header.packet_type = BATADV_UNICAST; 334 /* set unicast ttl */ 335 unicast_packet->header.ttl = BATADV_TTL; 336 /* copy the destination for faster routing */ 337 memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN); 338 /* set the destination tt version number */ 339 unicast_packet->ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn); 340 341 /* inform the destination node that we are still missing a correct route 342 * for this client. The destination will receive this packet and will 343 * try to reroute it because the ttvn contained in the header is less 344 * than the current one 345 */ 346 if (batadv_tt_global_client_is_roaming(bat_priv, ethhdr->h_dest)) 347 unicast_packet->ttvn = unicast_packet->ttvn - 1; 348 349 dev_mtu = neigh_node->if_incoming->net_dev->mtu; 350 if (atomic_read(&bat_priv->fragmentation) && 351 data_len + sizeof(*unicast_packet) > dev_mtu) { 352 /* send frag skb decreases ttl */ 353 unicast_packet->header.ttl++; 354 ret = batadv_frag_send_skb(skb, bat_priv, 355 neigh_node->if_incoming, 356 neigh_node->addr); 357 goto out; 358 } 359 360 batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr); 361 ret = 0; 362 goto out; 363 364out: 365 if (neigh_node) 366 batadv_neigh_node_free_ref(neigh_node); 367 if (orig_node) 368 batadv_orig_node_free_ref(orig_node); 369 if (ret == 1) 370 kfree_skb(skb); 371 return ret; 372} 373