1/* 2 * net/tipc/discover.c 3 * 4 * Copyright (c) 2003-2006, 2014, Ericsson AB 5 * Copyright (c) 2005-2006, 2010-2011, Wind River Systems 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the names of the copyright holders nor the names of its 17 * contributors may be used to endorse or promote products derived from 18 * this software without specific prior written permission. 19 * 20 * Alternatively, this software may be distributed under the terms of the 21 * GNU General Public License ("GPL") version 2 as published by the Free 22 * Software Foundation. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 25 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 28 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 34 * POSSIBILITY OF SUCH DAMAGE. 35 */ 36 37#include "core.h" 38#include "link.h" 39#include "discover.h" 40 41#define TIPC_LINK_REQ_INIT 125 /* min delay during bearer start up */ 42#define TIPC_LINK_REQ_FAST 1000 /* max delay if bearer has no links */ 43#define TIPC_LINK_REQ_SLOW 60000 /* max delay if bearer has links */ 44#define TIPC_LINK_REQ_INACTIVE 0xffffffff /* indicates no timer in use */ 45 46 47/** 48 * struct tipc_link_req - information about an ongoing link setup request 49 * @bearer_id: identity of bearer issuing requests 50 * @dest: destination address for request messages 51 * @domain: network domain to which links can be established 52 * @num_nodes: number of nodes currently discovered (i.e. with an active link) 53 * @lock: spinlock for controlling access to requests 54 * @buf: request message to be (repeatedly) sent 55 * @timer: timer governing period between requests 56 * @timer_intv: current interval between requests (in ms) 57 */ 58struct tipc_link_req { 59 u32 bearer_id; 60 struct tipc_media_addr dest; 61 u32 domain; 62 int num_nodes; 63 spinlock_t lock; 64 struct sk_buff *buf; 65 struct timer_list timer; 66 unsigned int timer_intv; 67}; 68 69/** 70 * tipc_disc_init_msg - initialize a link setup message 71 * @type: message type (request or response) 72 * @b_ptr: ptr to bearer issuing message 73 */ 74static void tipc_disc_init_msg(struct sk_buff *buf, u32 type, 75 struct tipc_bearer *b_ptr) 76{ 77 struct tipc_msg *msg; 78 u32 dest_domain = b_ptr->domain; 79 80 msg = buf_msg(buf); 81 tipc_msg_init(msg, LINK_CONFIG, type, INT_H_SIZE, dest_domain); 82 msg_set_non_seq(msg, 1); 83 msg_set_node_sig(msg, tipc_random); 84 msg_set_dest_domain(msg, dest_domain); 85 msg_set_bc_netid(msg, tipc_net_id); 86 b_ptr->media->addr2msg(msg_media_addr(msg), &b_ptr->addr); 87} 88 89/** 90 * disc_dupl_alert - issue node address duplication alert 91 * @b_ptr: pointer to bearer detecting duplication 92 * @node_addr: duplicated node address 93 * @media_addr: media address advertised by duplicated node 94 */ 95static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr, 96 struct tipc_media_addr *media_addr) 97{ 98 char node_addr_str[16]; 99 char media_addr_str[64]; 100 101 tipc_addr_string_fill(node_addr_str, node_addr); 102 tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str), 103 media_addr); 104 pr_warn("Duplicate %s using %s seen on <%s>\n", node_addr_str, 105 media_addr_str, b_ptr->name); 106} 107 108/** 109 * tipc_disc_rcv - handle incoming discovery message (request or response) 110 * @buf: buffer containing message 111 * @bearer: bearer that message arrived on 112 */ 113void tipc_disc_rcv(struct sk_buff *buf, struct tipc_bearer *bearer) 114{ 115 struct tipc_node *node; 116 struct tipc_link *link; 117 struct tipc_media_addr maddr; 118 struct sk_buff *rbuf; 119 struct tipc_msg *msg = buf_msg(buf); 120 u32 ddom = msg_dest_domain(msg); 121 u32 onode = msg_prevnode(msg); 122 u32 net_id = msg_bc_netid(msg); 123 u32 mtyp = msg_type(msg); 124 u32 signature = msg_node_sig(msg); 125 bool addr_match = false; 126 bool sign_match = false; 127 bool link_up = false; 128 bool accept_addr = false; 129 bool accept_sign = false; 130 bool respond = false; 131 132 bearer->media->msg2addr(bearer, &maddr, msg_media_addr(msg)); 133 kfree_skb(buf); 134 135 /* Ensure message from node is valid and communication is permitted */ 136 if (net_id != tipc_net_id) 137 return; 138 if (maddr.broadcast) 139 return; 140 if (!tipc_addr_domain_valid(ddom)) 141 return; 142 if (!tipc_addr_node_valid(onode)) 143 return; 144 145 if (in_own_node(onode)) { 146 if (memcmp(&maddr, &bearer->addr, sizeof(maddr))) 147 disc_dupl_alert(bearer, tipc_own_addr, &maddr); 148 return; 149 } 150 if (!tipc_in_scope(ddom, tipc_own_addr)) 151 return; 152 if (!tipc_in_scope(bearer->domain, onode)) 153 return; 154 155 /* Locate, or if necessary, create, node: */ 156 node = tipc_node_find(onode); 157 if (!node) 158 node = tipc_node_create(onode); 159 if (!node) 160 return; 161 162 tipc_node_lock(node); 163 link = node->links[bearer->identity]; 164 165 /* Prepare to validate requesting node's signature and media address */ 166 sign_match = (signature == node->signature); 167 addr_match = link && !memcmp(&link->media_addr, &maddr, sizeof(maddr)); 168 link_up = link && tipc_link_is_up(link); 169 170 171 /* These three flags give us eight permutations: */ 172 173 if (sign_match && addr_match && link_up) { 174 /* All is fine. Do nothing. */ 175 } else if (sign_match && addr_match && !link_up) { 176 /* Respond. The link will come up in due time */ 177 respond = true; 178 } else if (sign_match && !addr_match && link_up) { 179 /* Peer has changed i/f address without rebooting. 180 * If so, the link will reset soon, and the next 181 * discovery will be accepted. So we can ignore it. 182 * It may also be an cloned or malicious peer having 183 * chosen the same node address and signature as an 184 * existing one. 185 * Ignore requests until the link goes down, if ever. 186 */ 187 disc_dupl_alert(bearer, onode, &maddr); 188 } else if (sign_match && !addr_match && !link_up) { 189 /* Peer link has changed i/f address without rebooting. 190 * It may also be a cloned or malicious peer; we can't 191 * distinguish between the two. 192 * The signature is correct, so we must accept. 193 */ 194 accept_addr = true; 195 respond = true; 196 } else if (!sign_match && addr_match && link_up) { 197 /* Peer node rebooted. Two possibilities: 198 * - Delayed re-discovery; this link endpoint has already 199 * reset and re-established contact with the peer, before 200 * receiving a discovery message from that node. 201 * (The peer happened to receive one from this node first). 202 * - The peer came back so fast that our side has not 203 * discovered it yet. Probing from this side will soon 204 * reset the link, since there can be no working link 205 * endpoint at the peer end, and the link will re-establish. 206 * Accept the signature, since it comes from a known peer. 207 */ 208 accept_sign = true; 209 } else if (!sign_match && addr_match && !link_up) { 210 /* The peer node has rebooted. 211 * Accept signature, since it is a known peer. 212 */ 213 accept_sign = true; 214 respond = true; 215 } else if (!sign_match && !addr_match && link_up) { 216 /* Peer rebooted with new address, or a new/duplicate peer. 217 * Ignore until the link goes down, if ever. 218 */ 219 disc_dupl_alert(bearer, onode, &maddr); 220 } else if (!sign_match && !addr_match && !link_up) { 221 /* Peer rebooted with new address, or it is a new peer. 222 * Accept signature and address. 223 */ 224 accept_sign = true; 225 accept_addr = true; 226 respond = true; 227 } 228 229 if (accept_sign) 230 node->signature = signature; 231 232 if (accept_addr) { 233 if (!link) 234 link = tipc_link_create(node, bearer, &maddr); 235 if (link) { 236 memcpy(&link->media_addr, &maddr, sizeof(maddr)); 237 tipc_link_reset(link); 238 } else { 239 respond = false; 240 } 241 } 242 243 /* Send response, if necessary */ 244 if (respond && (mtyp == DSC_REQ_MSG)) { 245 rbuf = tipc_buf_acquire(INT_H_SIZE); 246 if (rbuf) { 247 tipc_disc_init_msg(rbuf, DSC_RESP_MSG, bearer); 248 tipc_bearer_send(bearer->identity, rbuf, &maddr); 249 kfree_skb(rbuf); 250 } 251 } 252 tipc_node_unlock(node); 253} 254 255/** 256 * disc_update - update frequency of periodic link setup requests 257 * @req: ptr to link request structure 258 * 259 * Reinitiates discovery process if discovery object has no associated nodes 260 * and is either not currently searching or is searching at a slow rate 261 */ 262static void disc_update(struct tipc_link_req *req) 263{ 264 if (!req->num_nodes) { 265 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) || 266 (req->timer_intv > TIPC_LINK_REQ_FAST)) { 267 req->timer_intv = TIPC_LINK_REQ_INIT; 268 k_start_timer(&req->timer, req->timer_intv); 269 } 270 } 271} 272 273/** 274 * tipc_disc_add_dest - increment set of discovered nodes 275 * @req: ptr to link request structure 276 */ 277void tipc_disc_add_dest(struct tipc_link_req *req) 278{ 279 spin_lock_bh(&req->lock); 280 req->num_nodes++; 281 spin_unlock_bh(&req->lock); 282} 283 284/** 285 * tipc_disc_remove_dest - decrement set of discovered nodes 286 * @req: ptr to link request structure 287 */ 288void tipc_disc_remove_dest(struct tipc_link_req *req) 289{ 290 spin_lock_bh(&req->lock); 291 req->num_nodes--; 292 disc_update(req); 293 spin_unlock_bh(&req->lock); 294} 295 296/** 297 * disc_timeout - send a periodic link setup request 298 * @req: ptr to link request structure 299 * 300 * Called whenever a link setup request timer associated with a bearer expires. 301 */ 302static void disc_timeout(struct tipc_link_req *req) 303{ 304 int max_delay; 305 306 spin_lock_bh(&req->lock); 307 308 /* Stop searching if only desired node has been found */ 309 if (tipc_node(req->domain) && req->num_nodes) { 310 req->timer_intv = TIPC_LINK_REQ_INACTIVE; 311 goto exit; 312 } 313 314 /* 315 * Send discovery message, then update discovery timer 316 * 317 * Keep doubling time between requests until limit is reached; 318 * hold at fast polling rate if don't have any associated nodes, 319 * otherwise hold at slow polling rate 320 */ 321 tipc_bearer_send(req->bearer_id, req->buf, &req->dest); 322 323 324 req->timer_intv *= 2; 325 if (req->num_nodes) 326 max_delay = TIPC_LINK_REQ_SLOW; 327 else 328 max_delay = TIPC_LINK_REQ_FAST; 329 if (req->timer_intv > max_delay) 330 req->timer_intv = max_delay; 331 332 k_start_timer(&req->timer, req->timer_intv); 333exit: 334 spin_unlock_bh(&req->lock); 335} 336 337/** 338 * tipc_disc_create - create object to send periodic link setup requests 339 * @b_ptr: ptr to bearer issuing requests 340 * @dest: destination address for request messages 341 * @dest_domain: network domain to which links can be established 342 * 343 * Returns 0 if successful, otherwise -errno. 344 */ 345int tipc_disc_create(struct tipc_bearer *b_ptr, struct tipc_media_addr *dest) 346{ 347 struct tipc_link_req *req; 348 349 req = kmalloc(sizeof(*req), GFP_ATOMIC); 350 if (!req) 351 return -ENOMEM; 352 353 req->buf = tipc_buf_acquire(INT_H_SIZE); 354 if (!req->buf) { 355 kfree(req); 356 return -ENOMEM; 357 } 358 359 tipc_disc_init_msg(req->buf, DSC_REQ_MSG, b_ptr); 360 memcpy(&req->dest, dest, sizeof(*dest)); 361 req->bearer_id = b_ptr->identity; 362 req->domain = b_ptr->domain; 363 req->num_nodes = 0; 364 req->timer_intv = TIPC_LINK_REQ_INIT; 365 spin_lock_init(&req->lock); 366 k_init_timer(&req->timer, (Handler)disc_timeout, (unsigned long)req); 367 k_start_timer(&req->timer, req->timer_intv); 368 b_ptr->link_req = req; 369 tipc_bearer_send(req->bearer_id, req->buf, &req->dest); 370 return 0; 371} 372 373/** 374 * tipc_disc_delete - destroy object sending periodic link setup requests 375 * @req: ptr to link request structure 376 */ 377void tipc_disc_delete(struct tipc_link_req *req) 378{ 379 k_cancel_timer(&req->timer); 380 k_term_timer(&req->timer); 381 kfree_skb(req->buf); 382 kfree(req); 383} 384 385/** 386 * tipc_disc_reset - reset object to send periodic link setup requests 387 * @b_ptr: ptr to bearer issuing requests 388 * @dest_domain: network domain to which links can be established 389 */ 390void tipc_disc_reset(struct tipc_bearer *b_ptr) 391{ 392 struct tipc_link_req *req = b_ptr->link_req; 393 394 spin_lock_bh(&req->lock); 395 tipc_disc_init_msg(req->buf, DSC_REQ_MSG, b_ptr); 396 req->bearer_id = b_ptr->identity; 397 req->domain = b_ptr->domain; 398 req->num_nodes = 0; 399 req->timer_intv = TIPC_LINK_REQ_INIT; 400 k_start_timer(&req->timer, req->timer_intv); 401 tipc_bearer_send(req->bearer_id, req->buf, &req->dest); 402 spin_unlock_bh(&req->lock); 403} 404