unicast.c revision 567db7b0b7c0a94cc62846f8ebb429bdda2884bc
1/* 2 * Copyright (C) 2010-2012 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(*unicast_packet); 43 int uni_diff = sizeof(*up) - 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 if (skb_linearize(skb) < 0 || skb_linearize(tmp_skb) < 0) 54 goto err; 55 56 skb_pull(tmp_skb, sizeof(*up)); 57 if (pskb_expand_head(skb, 0, tmp_skb->len, GFP_ATOMIC) < 0) 58 goto err; 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->header.packet_type = BAT_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 frag_create_entry(struct list_head *head, 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 frag_create_buffer(struct list_head *head) 97{ 98 int i; 99 struct frag_packet_list_entry *tfp; 100 101 for (i = 0; i < FRAG_BUFFER_SIZE; i++) { 102 tfp = kmalloc(sizeof(*tfp), GFP_ATOMIC); 103 if (!tfp) { 104 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 *frag_search_packet(struct list_head *head, 117 const struct unicast_frag_packet *up) 118{ 119 struct frag_packet_list_entry *tfp; 120 struct unicast_frag_packet *tmp_up = NULL; 121 uint16_t search_seqno; 122 123 if (up->flags & UNI_FRAG_HEAD) 124 search_seqno = ntohs(up->seqno)+1; 125 else 126 search_seqno = ntohs(up->seqno)-1; 127 128 list_for_each_entry(tfp, head, list) { 129 130 if (!tfp->skb) 131 continue; 132 133 if (tfp->seqno == ntohs(up->seqno)) 134 goto mov_tail; 135 136 tmp_up = (struct unicast_frag_packet *)tfp->skb->data; 137 138 if (tfp->seqno == search_seqno) { 139 140 if ((tmp_up->flags & UNI_FRAG_HEAD) != 141 (up->flags & UNI_FRAG_HEAD)) 142 return tfp; 143 else 144 goto mov_tail; 145 } 146 } 147 return NULL; 148 149mov_tail: 150 list_move_tail(&tfp->list, head); 151 return NULL; 152} 153 154void frag_list_free(struct list_head *head) 155{ 156 struct frag_packet_list_entry *pf, *tmp_pf; 157 158 if (!list_empty(head)) { 159 160 list_for_each_entry_safe(pf, tmp_pf, head, list) { 161 kfree_skb(pf->skb); 162 list_del(&pf->list); 163 kfree(pf); 164 } 165 } 166 return; 167} 168 169/* frag_reassemble_skb(): 170 * returns NET_RX_DROP if the operation failed - skb is left intact 171 * returns NET_RX_SUCCESS if the fragment was buffered (skb_new will be NULL) 172 * or the skb could be reassembled (skb_new will point to the new packet and 173 * skb was freed) 174 */ 175int frag_reassemble_skb(struct sk_buff *skb, struct bat_priv *bat_priv, 176 struct sk_buff **new_skb) 177{ 178 struct orig_node *orig_node; 179 struct frag_packet_list_entry *tmp_frag_entry; 180 int ret = NET_RX_DROP; 181 struct unicast_frag_packet *unicast_packet = 182 (struct unicast_frag_packet *)skb->data; 183 184 *new_skb = NULL; 185 186 orig_node = orig_hash_find(bat_priv, unicast_packet->orig); 187 if (!orig_node) 188 goto out; 189 190 orig_node->last_frag_packet = jiffies; 191 192 if (list_empty(&orig_node->frag_list) && 193 frag_create_buffer(&orig_node->frag_list)) { 194 pr_debug("couldn't create frag buffer\n"); 195 goto out; 196 } 197 198 tmp_frag_entry = frag_search_packet(&orig_node->frag_list, 199 unicast_packet); 200 201 if (!tmp_frag_entry) { 202 frag_create_entry(&orig_node->frag_list, skb); 203 ret = NET_RX_SUCCESS; 204 goto out; 205 } 206 207 *new_skb = frag_merge_packet(&orig_node->frag_list, tmp_frag_entry, 208 skb); 209 /* if not, merge failed */ 210 if (*new_skb) 211 ret = NET_RX_SUCCESS; 212 213out: 214 if (orig_node) 215 orig_node_free_ref(orig_node); 216 return ret; 217} 218 219int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv, 220 struct hard_iface *hard_iface, const uint8_t dstaddr[]) 221{ 222 struct unicast_packet tmp_uc, *unicast_packet; 223 struct hard_iface *primary_if; 224 struct sk_buff *frag_skb; 225 struct unicast_frag_packet *frag1, *frag2; 226 int uc_hdr_len = sizeof(*unicast_packet); 227 int ucf_hdr_len = sizeof(*frag1); 228 int data_len = skb->len - uc_hdr_len; 229 int large_tail = 0, ret = NET_RX_DROP; 230 uint16_t seqno; 231 232 primary_if = primary_if_get_selected(bat_priv); 233 if (!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(tmp_uc)); 253 254 frag1->header.ttl--; 255 frag1->header.version = COMPAT_VERSION; 256 frag1->header.packet_type = BAT_UNICAST_FRAG; 257 258 memcpy(frag1->orig, primary_if->net_dev->dev_addr, ETH_ALEN); 259 memcpy(frag2, frag1, sizeof(*frag2)); 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, &hard_iface->frag_seqno); 268 frag1->seqno = htons(seqno - 1); 269 frag2->seqno = htons(seqno); 270 271 send_skb_packet(skb, hard_iface, dstaddr); 272 send_skb_packet(frag_skb, hard_iface, dstaddr); 273 ret = NET_RX_SUCCESS; 274 goto out; 275 276drop_frag: 277 kfree_skb(frag_skb); 278dropped: 279 kfree_skb(skb); 280out: 281 if (primary_if) 282 hardif_free_ref(primary_if); 283 return ret; 284} 285 286int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv) 287{ 288 struct ethhdr *ethhdr = (struct ethhdr *)skb->data; 289 struct unicast_packet *unicast_packet; 290 struct orig_node *orig_node; 291 struct neigh_node *neigh_node; 292 int data_len = skb->len; 293 int ret = 1; 294 295 /* get routing information */ 296 if (is_multicast_ether_addr(ethhdr->h_dest)) { 297 orig_node = gw_get_selected_orig(bat_priv); 298 if (orig_node) 299 goto find_router; 300 } 301 302 /* check for tt host - increases orig_node refcount. 303 * returns NULL in case of AP isolation */ 304 orig_node = transtable_search(bat_priv, ethhdr->h_source, 305 ethhdr->h_dest); 306 307find_router: 308 /** 309 * find_router(): 310 * - if orig_node is NULL it returns NULL 311 * - increases neigh_nodes refcount if found. 312 */ 313 neigh_node = find_router(bat_priv, orig_node, NULL); 314 315 if (!neigh_node) 316 goto out; 317 318 if (my_skb_head_push(skb, sizeof(*unicast_packet)) < 0) 319 goto out; 320 321 unicast_packet = (struct unicast_packet *)skb->data; 322 323 unicast_packet->header.version = COMPAT_VERSION; 324 /* batman packet type: unicast */ 325 unicast_packet->header.packet_type = BAT_UNICAST; 326 /* set unicast ttl */ 327 unicast_packet->header.ttl = TTL; 328 /* copy the destination for faster routing */ 329 memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN); 330 /* set the destination tt version number */ 331 unicast_packet->ttvn = 332 (uint8_t)atomic_read(&orig_node->last_ttvn); 333 334 if (atomic_read(&bat_priv->fragmentation) && 335 data_len + sizeof(*unicast_packet) > 336 neigh_node->if_incoming->net_dev->mtu) { 337 /* send frag skb decreases ttl */ 338 unicast_packet->header.ttl++; 339 ret = frag_send_skb(skb, bat_priv, 340 neigh_node->if_incoming, neigh_node->addr); 341 goto out; 342 } 343 344 send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr); 345 ret = 0; 346 goto out; 347 348out: 349 if (neigh_node) 350 neigh_node_free_ref(neigh_node); 351 if (orig_node) 352 orig_node_free_ref(orig_node); 353 if (ret == 1) 354 kfree_skb(skb); 355 return ret; 356} 357