unicast.c revision 9cfc7bd608b97463993b4f3e4775d99022253f8d
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 *frag_merge_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 struct unicast_packet *unicast_packet; 40 int hdr_len = sizeof(*unicast_packet); 41 int uni_diff = sizeof(*up) - hdr_len; 42 43 /* set skb to the first part and tmp_skb to the second part */ 44 if (up->flags & UNI_FRAG_HEAD) { 45 tmp_skb = tfp->skb; 46 } else { 47 tmp_skb = skb; 48 skb = tfp->skb; 49 } 50 51 if (skb_linearize(skb) < 0 || skb_linearize(tmp_skb) < 0) 52 goto err; 53 54 skb_pull(tmp_skb, sizeof(*up)); 55 if (pskb_expand_head(skb, 0, tmp_skb->len, GFP_ATOMIC) < 0) 56 goto err; 57 58 /* move free entry to end */ 59 tfp->skb = NULL; 60 tfp->seqno = 0; 61 list_move_tail(&tfp->list, head); 62 63 memcpy(skb_put(skb, tmp_skb->len), tmp_skb->data, tmp_skb->len); 64 kfree_skb(tmp_skb); 65 66 memmove(skb->data + uni_diff, skb->data, hdr_len); 67 unicast_packet = (struct unicast_packet *)skb_pull(skb, uni_diff); 68 unicast_packet->header.packet_type = BAT_UNICAST; 69 70 return skb; 71 72err: 73 /* free buffered skb, skb will be freed later */ 74 kfree_skb(tfp->skb); 75 return NULL; 76} 77 78static void frag_create_entry(struct list_head *head, struct sk_buff *skb) 79{ 80 struct frag_packet_list_entry *tfp; 81 struct unicast_frag_packet *up = 82 (struct unicast_frag_packet *)skb->data; 83 84 /* free and oldest packets stand at the end */ 85 tfp = list_entry((head)->prev, typeof(*tfp), list); 86 kfree_skb(tfp->skb); 87 88 tfp->seqno = ntohs(up->seqno); 89 tfp->skb = skb; 90 list_move(&tfp->list, head); 91 return; 92} 93 94static int frag_create_buffer(struct list_head *head) 95{ 96 int i; 97 struct frag_packet_list_entry *tfp; 98 99 for (i = 0; i < FRAG_BUFFER_SIZE; i++) { 100 tfp = kmalloc(sizeof(*tfp), GFP_ATOMIC); 101 if (!tfp) { 102 batadv_frag_list_free(head); 103 return -ENOMEM; 104 } 105 tfp->skb = NULL; 106 tfp->seqno = 0; 107 INIT_LIST_HEAD(&tfp->list); 108 list_add(&tfp->list, head); 109 } 110 111 return 0; 112} 113 114static struct frag_packet_list_entry *frag_search_packet(struct list_head *head, 115 const struct unicast_frag_packet *up) 116{ 117 struct frag_packet_list_entry *tfp; 118 struct unicast_frag_packet *tmp_up = NULL; 119 uint16_t search_seqno; 120 121 if (up->flags & UNI_FRAG_HEAD) 122 search_seqno = ntohs(up->seqno)+1; 123 else 124 search_seqno = ntohs(up->seqno)-1; 125 126 list_for_each_entry(tfp, head, list) { 127 128 if (!tfp->skb) 129 continue; 130 131 if (tfp->seqno == ntohs(up->seqno)) 132 goto mov_tail; 133 134 tmp_up = (struct unicast_frag_packet *)tfp->skb->data; 135 136 if (tfp->seqno == search_seqno) { 137 138 if ((tmp_up->flags & UNI_FRAG_HEAD) != 139 (up->flags & UNI_FRAG_HEAD)) 140 return tfp; 141 else 142 goto mov_tail; 143 } 144 } 145 return NULL; 146 147mov_tail: 148 list_move_tail(&tfp->list, head); 149 return NULL; 150} 151 152void batadv_frag_list_free(struct list_head *head) 153{ 154 struct frag_packet_list_entry *pf, *tmp_pf; 155 156 if (!list_empty(head)) { 157 158 list_for_each_entry_safe(pf, tmp_pf, head, list) { 159 kfree_skb(pf->skb); 160 list_del(&pf->list); 161 kfree(pf); 162 } 163 } 164 return; 165} 166 167/* frag_reassemble_skb(): 168 * returns NET_RX_DROP if the operation failed - skb is left intact 169 * returns NET_RX_SUCCESS if the fragment was buffered (skb_new will be NULL) 170 * or the skb could be reassembled (skb_new will point to the new packet and 171 * skb was freed) 172 */ 173int batadv_frag_reassemble_skb(struct sk_buff *skb, struct bat_priv *bat_priv, 174 struct sk_buff **new_skb) 175{ 176 struct orig_node *orig_node; 177 struct frag_packet_list_entry *tmp_frag_entry; 178 int ret = NET_RX_DROP; 179 struct unicast_frag_packet *unicast_packet = 180 (struct unicast_frag_packet *)skb->data; 181 182 *new_skb = NULL; 183 184 orig_node = orig_hash_find(bat_priv, unicast_packet->orig); 185 if (!orig_node) 186 goto out; 187 188 orig_node->last_frag_packet = jiffies; 189 190 if (list_empty(&orig_node->frag_list) && 191 frag_create_buffer(&orig_node->frag_list)) { 192 pr_debug("couldn't create frag buffer\n"); 193 goto out; 194 } 195 196 tmp_frag_entry = frag_search_packet(&orig_node->frag_list, 197 unicast_packet); 198 199 if (!tmp_frag_entry) { 200 frag_create_entry(&orig_node->frag_list, skb); 201 ret = NET_RX_SUCCESS; 202 goto out; 203 } 204 205 *new_skb = frag_merge_packet(&orig_node->frag_list, tmp_frag_entry, 206 skb); 207 /* if not, merge failed */ 208 if (*new_skb) 209 ret = NET_RX_SUCCESS; 210 211out: 212 if (orig_node) 213 batadv_orig_node_free_ref(orig_node); 214 return ret; 215} 216 217int batadv_frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv, 218 struct hard_iface *hard_iface, const uint8_t dstaddr[]) 219{ 220 struct unicast_packet tmp_uc, *unicast_packet; 221 struct hard_iface *primary_if; 222 struct sk_buff *frag_skb; 223 struct unicast_frag_packet *frag1, *frag2; 224 int uc_hdr_len = sizeof(*unicast_packet); 225 int ucf_hdr_len = sizeof(*frag1); 226 int data_len = skb->len - uc_hdr_len; 227 int large_tail = 0, ret = NET_RX_DROP; 228 uint16_t seqno; 229 230 primary_if = primary_if_get_selected(bat_priv); 231 if (!primary_if) 232 goto dropped; 233 234 frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len); 235 if (!frag_skb) 236 goto dropped; 237 skb_reserve(frag_skb, ucf_hdr_len); 238 239 unicast_packet = (struct unicast_packet *)skb->data; 240 memcpy(&tmp_uc, unicast_packet, uc_hdr_len); 241 skb_split(skb, frag_skb, data_len / 2 + uc_hdr_len); 242 243 if (batadv_skb_head_push(skb, ucf_hdr_len - uc_hdr_len) < 0 || 244 batadv_skb_head_push(frag_skb, ucf_hdr_len) < 0) 245 goto drop_frag; 246 247 frag1 = (struct unicast_frag_packet *)skb->data; 248 frag2 = (struct unicast_frag_packet *)frag_skb->data; 249 250 memcpy(frag1, &tmp_uc, sizeof(tmp_uc)); 251 252 frag1->header.ttl--; 253 frag1->header.version = COMPAT_VERSION; 254 frag1->header.packet_type = BAT_UNICAST_FRAG; 255 256 memcpy(frag1->orig, primary_if->net_dev->dev_addr, ETH_ALEN); 257 memcpy(frag2, frag1, sizeof(*frag2)); 258 259 if (data_len & 1) 260 large_tail = UNI_FRAG_LARGETAIL; 261 262 frag1->flags = UNI_FRAG_HEAD | large_tail; 263 frag2->flags = large_tail; 264 265 seqno = atomic_add_return(2, &hard_iface->frag_seqno); 266 frag1->seqno = htons(seqno - 1); 267 frag2->seqno = htons(seqno); 268 269 batadv_send_skb_packet(skb, hard_iface, dstaddr); 270 batadv_send_skb_packet(frag_skb, hard_iface, dstaddr); 271 ret = NET_RX_SUCCESS; 272 goto out; 273 274drop_frag: 275 kfree_skb(frag_skb); 276dropped: 277 kfree_skb(skb); 278out: 279 if (primary_if) 280 hardif_free_ref(primary_if); 281 return ret; 282} 283 284int batadv_unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv) 285{ 286 struct ethhdr *ethhdr = (struct ethhdr *)skb->data; 287 struct unicast_packet *unicast_packet; 288 struct orig_node *orig_node; 289 struct neigh_node *neigh_node; 290 int data_len = skb->len; 291 int ret = 1; 292 293 /* get routing information */ 294 if (is_multicast_ether_addr(ethhdr->h_dest)) { 295 orig_node = batadv_gw_get_selected_orig(bat_priv); 296 if (orig_node) 297 goto find_router; 298 } 299 300 /* check for tt host - increases orig_node refcount. 301 * returns NULL in case of AP isolation 302 */ 303 orig_node = batadv_transtable_search(bat_priv, ethhdr->h_source, 304 ethhdr->h_dest); 305find_router: 306 /* find_router(): 307 * - if orig_node is NULL it returns NULL 308 * - increases neigh_nodes refcount if found. 309 */ 310 neigh_node = batadv_find_router(bat_priv, orig_node, NULL); 311 if (!neigh_node) 312 goto out; 313 314 if (batadv_skb_head_push(skb, sizeof(*unicast_packet)) < 0) 315 goto out; 316 317 unicast_packet = (struct unicast_packet *)skb->data; 318 319 unicast_packet->header.version = COMPAT_VERSION; 320 /* batman packet type: unicast */ 321 unicast_packet->header.packet_type = BAT_UNICAST; 322 /* set unicast ttl */ 323 unicast_packet->header.ttl = TTL; 324 /* copy the destination for faster routing */ 325 memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN); 326 /* set the destination tt version number */ 327 unicast_packet->ttvn = 328 (uint8_t)atomic_read(&orig_node->last_ttvn); 329 330 /* inform the destination node that we are still missing a correct route 331 * for this client. The destination will receive this packet and will 332 * try to reroute it because the ttvn contained in the header is less 333 * than the current one 334 */ 335 if (batadv_tt_global_client_is_roaming(bat_priv, ethhdr->h_dest)) 336 unicast_packet->ttvn = unicast_packet->ttvn - 1; 337 338 if (atomic_read(&bat_priv->fragmentation) && 339 data_len + sizeof(*unicast_packet) > 340 neigh_node->if_incoming->net_dev->mtu) { 341 /* send frag skb decreases ttl */ 342 unicast_packet->header.ttl++; 343 ret = batadv_frag_send_skb(skb, bat_priv, 344 neigh_node->if_incoming, 345 neigh_node->addr); 346 goto out; 347 } 348 349 batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr); 350 ret = 0; 351 goto out; 352 353out: 354 if (neigh_node) 355 batadv_neigh_node_free_ref(neigh_node); 356 if (orig_node) 357 batadv_orig_node_free_ref(orig_node); 358 if (ret == 1) 359 kfree_skb(skb); 360 return ret; 361} 362