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 MAX_H_SIZE, dest_domain); 90 msg_set_non_seq(msg, 1); 91 msg_set_node_sig(msg, tn->random); 92 msg_set_node_capabilities(msg, 0); 93 msg_set_dest_domain(msg, dest_domain); 94 msg_set_bc_netid(msg, tn->net_id); 95 b_ptr->media->addr2msg(msg_media_addr(msg), &b_ptr->addr); 96 } 97 98 /** 99 * disc_dupl_alert - issue node address duplication alert 100 * @b_ptr: pointer to bearer detecting duplication 101 * @node_addr: duplicated node address 102 * @media_addr: media address advertised by duplicated node 103 */ 104 static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr, 105 struct tipc_media_addr *media_addr) 106 { 107 char node_addr_str[16]; 108 char media_addr_str[64]; 109 110 tipc_addr_string_fill(node_addr_str, node_addr); 111 tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str), 112 media_addr); 113 pr_warn("Duplicate %s using %s seen on <%s>\n", node_addr_str, 114 media_addr_str, b_ptr->name); 115 } 116 117 /** 118 * tipc_disc_rcv - handle incoming discovery message (request or response) 119 * @net: the applicable net namespace 120 * @buf: buffer containing message 121 * @bearer: bearer that message arrived on 122 */ 123 void tipc_disc_rcv(struct net *net, struct sk_buff *buf, 124 struct tipc_bearer *bearer) 125 { 126 struct tipc_net *tn = net_generic(net, tipc_net_id); 127 struct tipc_node *node; 128 struct tipc_link *link; 129 struct tipc_media_addr maddr; 130 struct sk_buff *rbuf; 131 struct tipc_msg *msg = buf_msg(buf); 132 u32 ddom = msg_dest_domain(msg); 133 u32 onode = msg_prevnode(msg); 134 u32 net_id = msg_bc_netid(msg); 135 u32 mtyp = msg_type(msg); 136 u32 signature = msg_node_sig(msg); 137 u16 caps = msg_node_capabilities(msg); 138 bool addr_match = false; 139 bool sign_match = false; 140 bool link_up = false; 141 bool accept_addr = false; 142 bool accept_sign = false; 143 bool respond = false; 144 145 bearer->media->msg2addr(bearer, &maddr, msg_media_addr(msg)); 146 kfree_skb(buf); 147 148 /* Ensure message from node is valid and communication is permitted */ 149 if (net_id != tn->net_id) 150 return; 151 if (maddr.broadcast) 152 return; 153 if (!tipc_addr_domain_valid(ddom)) 154 return; 155 if (!tipc_addr_node_valid(onode)) 156 return; 157 158 if (in_own_node(net, onode)) { 159 if (memcmp(&maddr, &bearer->addr, sizeof(maddr))) 160 disc_dupl_alert(bearer, tn->own_addr, &maddr); 161 return; 162 } 163 if (!tipc_in_scope(ddom, tn->own_addr)) 164 return; 165 if (!tipc_in_scope(bearer->domain, onode)) 166 return; 167 168 node = tipc_node_create(net, onode); 169 if (!node) 170 return; 171 tipc_node_lock(node); 172 node->capabilities = caps; 173 link = node->links[bearer->identity]; 174 175 /* Prepare to validate requesting node's signature and media address */ 176 sign_match = (signature == node->signature); 177 addr_match = link && !memcmp(&link->media_addr, &maddr, sizeof(maddr)); 178 link_up = link && tipc_link_is_up(link); 179 180 181 /* These three flags give us eight permutations: */ 182 183 if (sign_match && addr_match && link_up) { 184 /* All is fine. Do nothing. */ 185 } else if (sign_match && addr_match && !link_up) { 186 /* Respond. The link will come up in due time */ 187 respond = true; 188 } else if (sign_match && !addr_match && link_up) { 189 /* Peer has changed i/f address without rebooting. 190 * If so, the link will reset soon, and the next 191 * discovery will be accepted. So we can ignore it. 192 * It may also be an cloned or malicious peer having 193 * chosen the same node address and signature as an 194 * existing one. 195 * Ignore requests until the link goes down, if ever. 196 */ 197 disc_dupl_alert(bearer, onode, &maddr); 198 } else if (sign_match && !addr_match && !link_up) { 199 /* Peer link has changed i/f address without rebooting. 200 * It may also be a cloned or malicious peer; we can't 201 * distinguish between the two. 202 * The signature is correct, so we must accept. 203 */ 204 accept_addr = true; 205 respond = true; 206 } else if (!sign_match && addr_match && link_up) { 207 /* Peer node rebooted. Two possibilities: 208 * - Delayed re-discovery; this link endpoint has already 209 * reset and re-established contact with the peer, before 210 * receiving a discovery message from that node. 211 * (The peer happened to receive one from this node first). 212 * - The peer came back so fast that our side has not 213 * discovered it yet. Probing from this side will soon 214 * reset the link, since there can be no working link 215 * endpoint at the peer end, and the link will re-establish. 216 * Accept the signature, since it comes from a known peer. 217 */ 218 accept_sign = true; 219 } else if (!sign_match && addr_match && !link_up) { 220 /* The peer node has rebooted. 221 * Accept signature, since it is a known peer. 222 */ 223 accept_sign = true; 224 respond = true; 225 } else if (!sign_match && !addr_match && link_up) { 226 /* Peer rebooted with new address, or a new/duplicate peer. 227 * Ignore until the link goes down, if ever. 228 */ 229 disc_dupl_alert(bearer, onode, &maddr); 230 } else if (!sign_match && !addr_match && !link_up) { 231 /* Peer rebooted with new address, or it is a new peer. 232 * Accept signature and address. 233 */ 234 accept_sign = true; 235 accept_addr = true; 236 respond = true; 237 } 238 239 if (accept_sign) 240 node->signature = signature; 241 242 if (accept_addr) { 243 if (!link) 244 link = tipc_link_create(node, bearer, &maddr); 245 if (link) { 246 memcpy(&link->media_addr, &maddr, sizeof(maddr)); 247 tipc_link_reset(link); 248 } else { 249 respond = false; 250 } 251 } 252 253 /* Send response, if necessary */ 254 if (respond && (mtyp == DSC_REQ_MSG)) { 255 rbuf = tipc_buf_acquire(MAX_H_SIZE); 256 if (rbuf) { 257 tipc_disc_init_msg(net, rbuf, DSC_RESP_MSG, bearer); 258 tipc_bearer_send(net, bearer->identity, rbuf, &maddr); 259 kfree_skb(rbuf); 260 } 261 } 262 tipc_node_unlock(node); 263 tipc_node_put(node); 264 } 265 266 /** 267 * disc_update - update frequency of periodic link setup requests 268 * @req: ptr to link request structure 269 * 270 * Reinitiates discovery process if discovery object has no associated nodes 271 * and is either not currently searching or is searching at a slow rate 272 */ 273 static void disc_update(struct tipc_link_req *req) 274 { 275 if (!req->num_nodes) { 276 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) || 277 (req->timer_intv > TIPC_LINK_REQ_FAST)) { 278 req->timer_intv = TIPC_LINK_REQ_INIT; 279 mod_timer(&req->timer, jiffies + req->timer_intv); 280 } 281 } 282 } 283 284 /** 285 * tipc_disc_add_dest - increment set of discovered nodes 286 * @req: ptr to link request structure 287 */ 288 void tipc_disc_add_dest(struct tipc_link_req *req) 289 { 290 spin_lock_bh(&req->lock); 291 req->num_nodes++; 292 spin_unlock_bh(&req->lock); 293 } 294 295 /** 296 * tipc_disc_remove_dest - decrement set of discovered nodes 297 * @req: ptr to link request structure 298 */ 299 void tipc_disc_remove_dest(struct tipc_link_req *req) 300 { 301 spin_lock_bh(&req->lock); 302 req->num_nodes--; 303 disc_update(req); 304 spin_unlock_bh(&req->lock); 305 } 306 307 /** 308 * disc_timeout - send a periodic link setup request 309 * @data: ptr to link request structure 310 * 311 * Called whenever a link setup request timer associated with a bearer expires. 312 */ 313 static void disc_timeout(unsigned long data) 314 { 315 struct tipc_link_req *req = (struct tipc_link_req *)data; 316 int max_delay; 317 318 spin_lock_bh(&req->lock); 319 320 /* Stop searching if only desired node has been found */ 321 if (tipc_node(req->domain) && req->num_nodes) { 322 req->timer_intv = TIPC_LINK_REQ_INACTIVE; 323 goto exit; 324 } 325 326 /* 327 * Send discovery message, then update discovery timer 328 * 329 * Keep doubling time between requests until limit is reached; 330 * hold at fast polling rate if don't have any associated nodes, 331 * otherwise hold at slow polling rate 332 */ 333 tipc_bearer_send(req->net, req->bearer_id, req->buf, &req->dest); 334 335 336 req->timer_intv *= 2; 337 if (req->num_nodes) 338 max_delay = TIPC_LINK_REQ_SLOW; 339 else 340 max_delay = TIPC_LINK_REQ_FAST; 341 if (req->timer_intv > max_delay) 342 req->timer_intv = max_delay; 343 344 mod_timer(&req->timer, jiffies + req->timer_intv); 345 exit: 346 spin_unlock_bh(&req->lock); 347 } 348 349 /** 350 * tipc_disc_create - create object to send periodic link setup requests 351 * @net: the applicable net namespace 352 * @b_ptr: ptr to bearer issuing requests 353 * @dest: destination address for request messages 354 * @dest_domain: network domain to which links can be established 355 * 356 * Returns 0 if successful, otherwise -errno. 357 */ 358 int tipc_disc_create(struct net *net, struct tipc_bearer *b_ptr, 359 struct tipc_media_addr *dest) 360 { 361 struct tipc_link_req *req; 362 363 req = kmalloc(sizeof(*req), GFP_ATOMIC); 364 if (!req) 365 return -ENOMEM; 366 req->buf = tipc_buf_acquire(MAX_H_SIZE); 367 if (!req->buf) { 368 kfree(req); 369 return -ENOMEM; 370 } 371 372 tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b_ptr); 373 memcpy(&req->dest, dest, sizeof(*dest)); 374 req->net = net; 375 req->bearer_id = b_ptr->identity; 376 req->domain = b_ptr->domain; 377 req->num_nodes = 0; 378 req->timer_intv = TIPC_LINK_REQ_INIT; 379 spin_lock_init(&req->lock); 380 setup_timer(&req->timer, disc_timeout, (unsigned long)req); 381 mod_timer(&req->timer, jiffies + req->timer_intv); 382 b_ptr->link_req = req; 383 tipc_bearer_send(net, req->bearer_id, req->buf, &req->dest); 384 return 0; 385 } 386 387 /** 388 * tipc_disc_delete - destroy object sending periodic link setup requests 389 * @req: ptr to link request structure 390 */ 391 void tipc_disc_delete(struct tipc_link_req *req) 392 { 393 del_timer_sync(&req->timer); 394 kfree_skb(req->buf); 395 kfree(req); 396 } 397 398 /** 399 * tipc_disc_reset - reset object to send periodic link setup requests 400 * @net: the applicable net namespace 401 * @b_ptr: ptr to bearer issuing requests 402 * @dest_domain: network domain to which links can be established 403 */ 404 void tipc_disc_reset(struct net *net, struct tipc_bearer *b_ptr) 405 { 406 struct tipc_link_req *req = b_ptr->link_req; 407 408 spin_lock_bh(&req->lock); 409 tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b_ptr); 410 req->net = net; 411 req->bearer_id = b_ptr->identity; 412 req->domain = b_ptr->domain; 413 req->num_nodes = 0; 414 req->timer_intv = TIPC_LINK_REQ_INIT; 415 mod_timer(&req->timer, jiffies + req->timer_intv); 416 tipc_bearer_send(net, req->bearer_id, req->buf, &req->dest); 417 spin_unlock_bh(&req->lock); 418 } 419