1 /* 2 * net/tipc/discover.c 3 * 4 * Copyright (c) 2003-2006, 2014-2015, 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 /* min delay during bearer start up */ 42 #define TIPC_LINK_REQ_INIT msecs_to_jiffies(125) 43 /* max delay if bearer has no links */ 44 #define TIPC_LINK_REQ_FAST msecs_to_jiffies(1000) 45 /* max delay if bearer has links */ 46 #define TIPC_LINK_REQ_SLOW msecs_to_jiffies(60000) 47 /* indicates no timer in use */ 48 #define TIPC_LINK_REQ_INACTIVE 0xffffffff 49 50 /** 51 * struct tipc_link_req - information about an ongoing link setup request 52 * @bearer_id: identity of bearer issuing requests 53 * @net: network namespace instance 54 * @dest: destination address for request messages 55 * @domain: network domain to which links can be established 56 * @num_nodes: number of nodes currently discovered (i.e. with an active link) 57 * @lock: spinlock for controlling access to requests 58 * @buf: request message to be (repeatedly) sent 59 * @timer: timer governing period between requests 60 * @timer_intv: current interval between requests (in ms) 61 */ 62 struct tipc_link_req { 63 u32 bearer_id; 64 struct tipc_media_addr dest; 65 struct net *net; 66 u32 domain; 67 int num_nodes; 68 spinlock_t lock; 69 struct sk_buff *buf; 70 struct timer_list timer; 71 unsigned long timer_intv; 72 }; 73 74 /** 75 * tipc_disc_init_msg - initialize a link setup message 76 * @net: the applicable net namespace 77 * @type: message type (request or response) 78 * @b_ptr: ptr to bearer issuing message 79 */ 80 static void tipc_disc_init_msg(struct net *net, struct sk_buff *buf, u32 type, 81 struct tipc_bearer *b_ptr) 82 { 83 struct tipc_net *tn = net_generic(net, tipc_net_id); 84 struct tipc_msg *msg; 85 u32 dest_domain = b_ptr->domain; 86 87 msg = buf_msg(buf); 88 tipc_msg_init(tn->own_addr, msg, LINK_CONFIG, type, 89 INT_H_SIZE, dest_domain); 90 msg_set_non_seq(msg, 1); 91 msg_set_node_sig(msg, tn->random); 92 msg_set_dest_domain(msg, dest_domain); 93 msg_set_bc_netid(msg, tn->net_id); 94 b_ptr->media->addr2msg(msg_media_addr(msg), &b_ptr->addr); 95 } 96 97 /** 98 * disc_dupl_alert - issue node address duplication alert 99 * @b_ptr: pointer to bearer detecting duplication 100 * @node_addr: duplicated node address 101 * @media_addr: media address advertised by duplicated node 102 */ 103 static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr, 104 struct tipc_media_addr *media_addr) 105 { 106 char node_addr_str[16]; 107 char media_addr_str[64]; 108 109 tipc_addr_string_fill(node_addr_str, node_addr); 110 tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str), 111 media_addr); 112 pr_warn("Duplicate %s using %s seen on <%s>\n", node_addr_str, 113 media_addr_str, b_ptr->name); 114 } 115 116 /** 117 * tipc_disc_rcv - handle incoming discovery message (request or response) 118 * @net: the applicable net namespace 119 * @buf: buffer containing message 120 * @bearer: bearer that message arrived on 121 */ 122 void tipc_disc_rcv(struct net *net, struct sk_buff *buf, 123 struct tipc_bearer *bearer) 124 { 125 struct tipc_net *tn = net_generic(net, tipc_net_id); 126 struct tipc_node *node; 127 struct tipc_link *link; 128 struct tipc_media_addr maddr; 129 struct sk_buff *rbuf; 130 struct tipc_msg *msg = buf_msg(buf); 131 u32 ddom = msg_dest_domain(msg); 132 u32 onode = msg_prevnode(msg); 133 u32 net_id = msg_bc_netid(msg); 134 u32 mtyp = msg_type(msg); 135 u32 signature = msg_node_sig(msg); 136 bool addr_match = false; 137 bool sign_match = false; 138 bool link_up = false; 139 bool accept_addr = false; 140 bool accept_sign = false; 141 bool respond = false; 142 143 bearer->media->msg2addr(bearer, &maddr, msg_media_addr(msg)); 144 kfree_skb(buf); 145 146 /* Ensure message from node is valid and communication is permitted */ 147 if (net_id != tn->net_id) 148 return; 149 if (maddr.broadcast) 150 return; 151 if (!tipc_addr_domain_valid(ddom)) 152 return; 153 if (!tipc_addr_node_valid(onode)) 154 return; 155 156 if (in_own_node(net, onode)) { 157 if (memcmp(&maddr, &bearer->addr, sizeof(maddr))) 158 disc_dupl_alert(bearer, tn->own_addr, &maddr); 159 return; 160 } 161 if (!tipc_in_scope(ddom, tn->own_addr)) 162 return; 163 if (!tipc_in_scope(bearer->domain, onode)) 164 return; 165 166 node = tipc_node_create(net, onode); 167 if (!node) 168 return; 169 tipc_node_lock(node); 170 link = node->links[bearer->identity]; 171 172 /* Prepare to validate requesting node's signature and media address */ 173 sign_match = (signature == node->signature); 174 addr_match = link && !memcmp(&link->media_addr, &maddr, sizeof(maddr)); 175 link_up = link && tipc_link_is_up(link); 176 177 178 /* These three flags give us eight permutations: */ 179 180 if (sign_match && addr_match && link_up) { 181 /* All is fine. Do nothing. */ 182 } else if (sign_match && addr_match && !link_up) { 183 /* Respond. The link will come up in due time */ 184 respond = true; 185 } else if (sign_match && !addr_match && link_up) { 186 /* Peer has changed i/f address without rebooting. 187 * If so, the link will reset soon, and the next 188 * discovery will be accepted. So we can ignore it. 189 * It may also be an cloned or malicious peer having 190 * chosen the same node address and signature as an 191 * existing one. 192 * Ignore requests until the link goes down, if ever. 193 */ 194 disc_dupl_alert(bearer, onode, &maddr); 195 } else if (sign_match && !addr_match && !link_up) { 196 /* Peer link has changed i/f address without rebooting. 197 * It may also be a cloned or malicious peer; we can't 198 * distinguish between the two. 199 * The signature is correct, so we must accept. 200 */ 201 accept_addr = true; 202 respond = true; 203 } else if (!sign_match && addr_match && link_up) { 204 /* Peer node rebooted. Two possibilities: 205 * - Delayed re-discovery; this link endpoint has already 206 * reset and re-established contact with the peer, before 207 * receiving a discovery message from that node. 208 * (The peer happened to receive one from this node first). 209 * - The peer came back so fast that our side has not 210 * discovered it yet. Probing from this side will soon 211 * reset the link, since there can be no working link 212 * endpoint at the peer end, and the link will re-establish. 213 * Accept the signature, since it comes from a known peer. 214 */ 215 accept_sign = true; 216 } else if (!sign_match && addr_match && !link_up) { 217 /* The peer node has rebooted. 218 * Accept signature, since it is a known peer. 219 */ 220 accept_sign = true; 221 respond = true; 222 } else if (!sign_match && !addr_match && link_up) { 223 /* Peer rebooted with new address, or a new/duplicate peer. 224 * Ignore until the link goes down, if ever. 225 */ 226 disc_dupl_alert(bearer, onode, &maddr); 227 } else if (!sign_match && !addr_match && !link_up) { 228 /* Peer rebooted with new address, or it is a new peer. 229 * Accept signature and address. 230 */ 231 accept_sign = true; 232 accept_addr = true; 233 respond = true; 234 } 235 236 if (accept_sign) 237 node->signature = signature; 238 239 if (accept_addr) { 240 if (!link) 241 link = tipc_link_create(node, bearer, &maddr); 242 if (link) { 243 memcpy(&link->media_addr, &maddr, sizeof(maddr)); 244 tipc_link_reset(link); 245 } else { 246 respond = false; 247 } 248 } 249 250 /* Send response, if necessary */ 251 if (respond && (mtyp == DSC_REQ_MSG)) { 252 rbuf = tipc_buf_acquire(INT_H_SIZE); 253 if (rbuf) { 254 tipc_disc_init_msg(net, rbuf, DSC_RESP_MSG, bearer); 255 tipc_bearer_send(net, bearer->identity, rbuf, &maddr); 256 kfree_skb(rbuf); 257 } 258 } 259 tipc_node_unlock(node); 260 } 261 262 /** 263 * disc_update - update frequency of periodic link setup requests 264 * @req: ptr to link request structure 265 * 266 * Reinitiates discovery process if discovery object has no associated nodes 267 * and is either not currently searching or is searching at a slow rate 268 */ 269 static void disc_update(struct tipc_link_req *req) 270 { 271 if (!req->num_nodes) { 272 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) || 273 (req->timer_intv > TIPC_LINK_REQ_FAST)) { 274 req->timer_intv = TIPC_LINK_REQ_INIT; 275 mod_timer(&req->timer, jiffies + req->timer_intv); 276 } 277 } 278 } 279 280 /** 281 * tipc_disc_add_dest - increment set of discovered nodes 282 * @req: ptr to link request structure 283 */ 284 void tipc_disc_add_dest(struct tipc_link_req *req) 285 { 286 spin_lock_bh(&req->lock); 287 req->num_nodes++; 288 spin_unlock_bh(&req->lock); 289 } 290 291 /** 292 * tipc_disc_remove_dest - decrement set of discovered nodes 293 * @req: ptr to link request structure 294 */ 295 void tipc_disc_remove_dest(struct tipc_link_req *req) 296 { 297 spin_lock_bh(&req->lock); 298 req->num_nodes--; 299 disc_update(req); 300 spin_unlock_bh(&req->lock); 301 } 302 303 /** 304 * disc_timeout - send a periodic link setup request 305 * @data: ptr to link request structure 306 * 307 * Called whenever a link setup request timer associated with a bearer expires. 308 */ 309 static void disc_timeout(unsigned long data) 310 { 311 struct tipc_link_req *req = (struct tipc_link_req *)data; 312 int max_delay; 313 314 spin_lock_bh(&req->lock); 315 316 /* Stop searching if only desired node has been found */ 317 if (tipc_node(req->domain) && req->num_nodes) { 318 req->timer_intv = TIPC_LINK_REQ_INACTIVE; 319 goto exit; 320 } 321 322 /* 323 * Send discovery message, then update discovery timer 324 * 325 * Keep doubling time between requests until limit is reached; 326 * hold at fast polling rate if don't have any associated nodes, 327 * otherwise hold at slow polling rate 328 */ 329 tipc_bearer_send(req->net, req->bearer_id, req->buf, &req->dest); 330 331 332 req->timer_intv *= 2; 333 if (req->num_nodes) 334 max_delay = TIPC_LINK_REQ_SLOW; 335 else 336 max_delay = TIPC_LINK_REQ_FAST; 337 if (req->timer_intv > max_delay) 338 req->timer_intv = max_delay; 339 340 mod_timer(&req->timer, jiffies + req->timer_intv); 341 exit: 342 spin_unlock_bh(&req->lock); 343 } 344 345 /** 346 * tipc_disc_create - create object to send periodic link setup requests 347 * @net: the applicable net namespace 348 * @b_ptr: ptr to bearer issuing requests 349 * @dest: destination address for request messages 350 * @dest_domain: network domain to which links can be established 351 * 352 * Returns 0 if successful, otherwise -errno. 353 */ 354 int tipc_disc_create(struct net *net, struct tipc_bearer *b_ptr, 355 struct tipc_media_addr *dest) 356 { 357 struct tipc_link_req *req; 358 359 req = kmalloc(sizeof(*req), GFP_ATOMIC); 360 if (!req) 361 return -ENOMEM; 362 363 req->buf = tipc_buf_acquire(INT_H_SIZE); 364 if (!req->buf) { 365 kfree(req); 366 return -ENOMEM; 367 } 368 369 tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b_ptr); 370 memcpy(&req->dest, dest, sizeof(*dest)); 371 req->net = net; 372 req->bearer_id = b_ptr->identity; 373 req->domain = b_ptr->domain; 374 req->num_nodes = 0; 375 req->timer_intv = TIPC_LINK_REQ_INIT; 376 spin_lock_init(&req->lock); 377 setup_timer(&req->timer, disc_timeout, (unsigned long)req); 378 mod_timer(&req->timer, jiffies + req->timer_intv); 379 b_ptr->link_req = req; 380 tipc_bearer_send(net, req->bearer_id, req->buf, &req->dest); 381 return 0; 382 } 383 384 /** 385 * tipc_disc_delete - destroy object sending periodic link setup requests 386 * @req: ptr to link request structure 387 */ 388 void tipc_disc_delete(struct tipc_link_req *req) 389 { 390 del_timer_sync(&req->timer); 391 kfree_skb(req->buf); 392 kfree(req); 393 } 394 395 /** 396 * tipc_disc_reset - reset object to send periodic link setup requests 397 * @net: the applicable net namespace 398 * @b_ptr: ptr to bearer issuing requests 399 * @dest_domain: network domain to which links can be established 400 */ 401 void tipc_disc_reset(struct net *net, struct tipc_bearer *b_ptr) 402 { 403 struct tipc_link_req *req = b_ptr->link_req; 404 405 spin_lock_bh(&req->lock); 406 tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b_ptr); 407 req->net = net; 408 req->bearer_id = b_ptr->identity; 409 req->domain = b_ptr->domain; 410 req->num_nodes = 0; 411 req->timer_intv = TIPC_LINK_REQ_INIT; 412 mod_timer(&req->timer, jiffies + req->timer_intv); 413 tipc_bearer_send(net, req->bearer_id, req->buf, &req->dest); 414 spin_unlock_bh(&req->lock); 415 } 416