unicast.c revision acd34afa89772f6379b642bb979d0a112328c769
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 frag_packet_list_entry *tfp, 35 struct sk_buff *skb) 36{ 37 struct unicast_frag_packet *up = 38 (struct unicast_frag_packet *)skb->data; 39 struct sk_buff *tmp_skb; 40 struct unicast_packet *unicast_packet; 41 int hdr_len = sizeof(*unicast_packet); 42 int uni_diff = sizeof(*up) - hdr_len; 43 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 unicast_packet *)skb_pull(skb, uni_diff); 69 unicast_packet->header.packet_type = BATADV_UNICAST; 70 71 return skb; 72 73err: 74 /* free buffered skb, skb will be freed later */ 75 kfree_skb(tfp->skb); 76 return NULL; 77} 78 79static void batadv_frag_create_entry(struct list_head *head, 80 struct sk_buff *skb) 81{ 82 struct frag_packet_list_entry *tfp; 83 struct unicast_frag_packet *up = 84 (struct unicast_frag_packet *)skb->data; 85 86 /* free and oldest packets stand at the end */ 87 tfp = list_entry((head)->prev, typeof(*tfp), list); 88 kfree_skb(tfp->skb); 89 90 tfp->seqno = ntohs(up->seqno); 91 tfp->skb = skb; 92 list_move(&tfp->list, head); 93 return; 94} 95 96static int batadv_frag_create_buffer(struct list_head *head) 97{ 98 int i; 99 struct frag_packet_list_entry *tfp; 100 101 for (i = 0; i < BATADV_FRAG_BUFFER_SIZE; i++) { 102 tfp = kmalloc(sizeof(*tfp), GFP_ATOMIC); 103 if (!tfp) { 104 batadv_frag_list_free(head); 105 return -ENOMEM; 106 } 107 tfp->skb = NULL; 108 tfp->seqno = 0; 109 INIT_LIST_HEAD(&tfp->list); 110 list_add(&tfp->list, head); 111 } 112 113 return 0; 114} 115 116static struct frag_packet_list_entry * 117batadv_frag_search_packet(struct list_head *head, 118 const struct unicast_frag_packet *up) 119{ 120 struct frag_packet_list_entry *tfp; 121 struct unicast_frag_packet *tmp_up = NULL; 122 uint16_t search_seqno; 123 124 if (up->flags & BATADV_UNI_FRAG_HEAD) 125 search_seqno = ntohs(up->seqno)+1; 126 else 127 search_seqno = ntohs(up->seqno)-1; 128 129 list_for_each_entry(tfp, head, list) { 130 131 if (!tfp->skb) 132 continue; 133 134 if (tfp->seqno == ntohs(up->seqno)) 135 goto mov_tail; 136 137 tmp_up = (struct unicast_frag_packet *)tfp->skb->data; 138 139 if (tfp->seqno == search_seqno) { 140 141 if ((tmp_up->flags & BATADV_UNI_FRAG_HEAD) != 142 (up->flags & BATADV_UNI_FRAG_HEAD)) 143 return tfp; 144 else 145 goto mov_tail; 146 } 147 } 148 return NULL; 149 150mov_tail: 151 list_move_tail(&tfp->list, head); 152 return NULL; 153} 154 155void batadv_frag_list_free(struct list_head *head) 156{ 157 struct frag_packet_list_entry *pf, *tmp_pf; 158 159 if (!list_empty(head)) { 160 161 list_for_each_entry_safe(pf, tmp_pf, head, list) { 162 kfree_skb(pf->skb); 163 list_del(&pf->list); 164 kfree(pf); 165 } 166 } 167 return; 168} 169 170/* frag_reassemble_skb(): 171 * returns NET_RX_DROP if the operation failed - skb is left intact 172 * returns NET_RX_SUCCESS if the fragment was buffered (skb_new will be NULL) 173 * or the skb could be reassembled (skb_new will point to the new packet and 174 * skb was freed) 175 */ 176int batadv_frag_reassemble_skb(struct sk_buff *skb, struct bat_priv *bat_priv, 177 struct sk_buff **new_skb) 178{ 179 struct orig_node *orig_node; 180 struct frag_packet_list_entry *tmp_frag_entry; 181 int ret = NET_RX_DROP; 182 struct unicast_frag_packet *unicast_packet = 183 (struct unicast_frag_packet *)skb->data; 184 185 *new_skb = NULL; 186 187 orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->orig); 188 if (!orig_node) 189 goto out; 190 191 orig_node->last_frag_packet = jiffies; 192 193 if (list_empty(&orig_node->frag_list) && 194 batadv_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 = batadv_frag_search_packet(&orig_node->frag_list, 200 unicast_packet); 201 202 if (!tmp_frag_entry) { 203 batadv_frag_create_entry(&orig_node->frag_list, skb); 204 ret = NET_RX_SUCCESS; 205 goto out; 206 } 207 208 *new_skb = batadv_frag_merge_packet(&orig_node->frag_list, 209 tmp_frag_entry, skb); 210 /* if not, merge failed */ 211 if (*new_skb) 212 ret = NET_RX_SUCCESS; 213 214out: 215 if (orig_node) 216 batadv_orig_node_free_ref(orig_node); 217 return ret; 218} 219 220int batadv_frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv, 221 struct hard_iface *hard_iface, const uint8_t dstaddr[]) 222{ 223 struct unicast_packet tmp_uc, *unicast_packet; 224 struct hard_iface *primary_if; 225 struct sk_buff *frag_skb; 226 struct unicast_frag_packet *frag1, *frag2; 227 int uc_hdr_len = sizeof(*unicast_packet); 228 int ucf_hdr_len = sizeof(*frag1); 229 int data_len = skb->len - uc_hdr_len; 230 int large_tail = 0, ret = NET_RX_DROP; 231 uint16_t seqno; 232 233 primary_if = batadv_primary_if_get_selected(bat_priv); 234 if (!primary_if) 235 goto dropped; 236 237 frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len); 238 if (!frag_skb) 239 goto dropped; 240 skb_reserve(frag_skb, ucf_hdr_len); 241 242 unicast_packet = (struct unicast_packet *)skb->data; 243 memcpy(&tmp_uc, unicast_packet, uc_hdr_len); 244 skb_split(skb, frag_skb, data_len / 2 + uc_hdr_len); 245 246 if (batadv_skb_head_push(skb, ucf_hdr_len - uc_hdr_len) < 0 || 247 batadv_skb_head_push(frag_skb, ucf_hdr_len) < 0) 248 goto drop_frag; 249 250 frag1 = (struct unicast_frag_packet *)skb->data; 251 frag2 = (struct unicast_frag_packet *)frag_skb->data; 252 253 memcpy(frag1, &tmp_uc, sizeof(tmp_uc)); 254 255 frag1->header.ttl--; 256 frag1->header.version = BATADV_COMPAT_VERSION; 257 frag1->header.packet_type = BATADV_UNICAST_FRAG; 258 259 memcpy(frag1->orig, primary_if->net_dev->dev_addr, ETH_ALEN); 260 memcpy(frag2, frag1, sizeof(*frag2)); 261 262 if (data_len & 1) 263 large_tail = BATADV_UNI_FRAG_LARGETAIL; 264 265 frag1->flags = BATADV_UNI_FRAG_HEAD | large_tail; 266 frag2->flags = large_tail; 267 268 seqno = atomic_add_return(2, &hard_iface->frag_seqno); 269 frag1->seqno = htons(seqno - 1); 270 frag2->seqno = htons(seqno); 271 272 batadv_send_skb_packet(skb, hard_iface, dstaddr); 273 batadv_send_skb_packet(frag_skb, hard_iface, dstaddr); 274 ret = NET_RX_SUCCESS; 275 goto out; 276 277drop_frag: 278 kfree_skb(frag_skb); 279dropped: 280 kfree_skb(skb); 281out: 282 if (primary_if) 283 batadv_hardif_free_ref(primary_if); 284 return ret; 285} 286 287int batadv_unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv) 288{ 289 struct ethhdr *ethhdr = (struct ethhdr *)skb->data; 290 struct unicast_packet *unicast_packet; 291 struct orig_node *orig_node; 292 struct neigh_node *neigh_node; 293 int data_len = skb->len; 294 int ret = 1; 295 296 /* get routing information */ 297 if (is_multicast_ether_addr(ethhdr->h_dest)) { 298 orig_node = batadv_gw_get_selected_orig(bat_priv); 299 if (orig_node) 300 goto find_router; 301 } 302 303 /* check for tt host - increases orig_node refcount. 304 * returns NULL in case of AP isolation 305 */ 306 orig_node = batadv_transtable_search(bat_priv, ethhdr->h_source, 307 ethhdr->h_dest); 308find_router: 309 /* find_router(): 310 * - if orig_node is NULL it returns NULL 311 * - increases neigh_nodes refcount if found. 312 */ 313 neigh_node = batadv_find_router(bat_priv, orig_node, NULL); 314 if (!neigh_node) 315 goto out; 316 317 if (batadv_skb_head_push(skb, sizeof(*unicast_packet)) < 0) 318 goto out; 319 320 unicast_packet = (struct unicast_packet *)skb->data; 321 322 unicast_packet->header.version = BATADV_COMPAT_VERSION; 323 /* batman packet type: unicast */ 324 unicast_packet->header.packet_type = BATADV_UNICAST; 325 /* set unicast ttl */ 326 unicast_packet->header.ttl = BATADV_TTL; 327 /* copy the destination for faster routing */ 328 memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN); 329 /* set the destination tt version number */ 330 unicast_packet->ttvn = 331 (uint8_t)atomic_read(&orig_node->last_ttvn); 332 333 /* inform the destination node that we are still missing a correct route 334 * for this client. The destination will receive this packet and will 335 * try to reroute it because the ttvn contained in the header is less 336 * than the current one 337 */ 338 if (batadv_tt_global_client_is_roaming(bat_priv, ethhdr->h_dest)) 339 unicast_packet->ttvn = unicast_packet->ttvn - 1; 340 341 if (atomic_read(&bat_priv->fragmentation) && 342 data_len + sizeof(*unicast_packet) > 343 neigh_node->if_incoming->net_dev->mtu) { 344 /* send frag skb decreases ttl */ 345 unicast_packet->header.ttl++; 346 ret = batadv_frag_send_skb(skb, bat_priv, 347 neigh_node->if_incoming, 348 neigh_node->addr); 349 goto out; 350 } 351 352 batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr); 353 ret = 0; 354 goto out; 355 356out: 357 if (neigh_node) 358 batadv_neigh_node_free_ref(neigh_node); 359 if (orig_node) 360 batadv_orig_node_free_ref(orig_node); 361 if (ret == 1) 362 kfree_skb(skb); 363 return ret; 364} 365