1 /* 2 * net/tipc/discover.c 3 * 4 * Copyright (c) 2003-2006, 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: 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 * @buf: request message to be (repeatedly) sent 54 * @timer: timer governing period between requests 55 * @timer_intv: current interval between requests (in ms) 56 */ 57 struct tipc_link_req { 58 struct tipc_bearer *bearer; 59 struct tipc_media_addr dest; 60 u32 domain; 61 int num_nodes; 62 struct sk_buff *buf; 63 struct timer_list timer; 64 unsigned int timer_intv; 65 }; 66 67 /** 68 * tipc_disc_init_msg - initialize a link setup message 69 * @type: message type (request or response) 70 * @dest_domain: network domain of node(s) which should respond to message 71 * @b_ptr: ptr to bearer issuing message 72 */ 73 74 static struct sk_buff *tipc_disc_init_msg(u32 type, 75 u32 dest_domain, 76 struct tipc_bearer *b_ptr) 77 { 78 struct sk_buff *buf = tipc_buf_acquire(INT_H_SIZE); 79 struct tipc_msg *msg; 80 81 if (buf) { 82 msg = buf_msg(buf); 83 tipc_msg_init(msg, LINK_CONFIG, type, INT_H_SIZE, dest_domain); 84 msg_set_non_seq(msg, 1); 85 msg_set_node_sig(msg, tipc_random); 86 msg_set_dest_domain(msg, dest_domain); 87 msg_set_bc_netid(msg, tipc_net_id); 88 b_ptr->media->addr2msg(&b_ptr->addr, msg_media_addr(msg)); 89 } 90 return buf; 91 } 92 93 /** 94 * disc_dupl_alert - issue node address duplication alert 95 * @b_ptr: pointer to bearer detecting duplication 96 * @node_addr: duplicated node address 97 * @media_addr: media address advertised by duplicated node 98 */ 99 100 static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr, 101 struct tipc_media_addr *media_addr) 102 { 103 char node_addr_str[16]; 104 char media_addr_str[64]; 105 struct print_buf pb; 106 107 tipc_addr_string_fill(node_addr_str, node_addr); 108 tipc_printbuf_init(&pb, media_addr_str, sizeof(media_addr_str)); 109 tipc_media_addr_printf(&pb, media_addr); 110 tipc_printbuf_validate(&pb); 111 warn("Duplicate %s using %s seen on <%s>\n", 112 node_addr_str, media_addr_str, b_ptr->name); 113 } 114 115 /** 116 * tipc_disc_recv_msg - handle incoming link setup message (request or response) 117 * @buf: buffer containing message 118 * @b_ptr: bearer that message arrived on 119 */ 120 121 void tipc_disc_recv_msg(struct sk_buff *buf, struct tipc_bearer *b_ptr) 122 { 123 struct tipc_node *n_ptr; 124 struct tipc_link *link; 125 struct tipc_media_addr media_addr; 126 struct sk_buff *rbuf; 127 struct tipc_msg *msg = buf_msg(buf); 128 u32 dest = msg_dest_domain(msg); 129 u32 orig = msg_prevnode(msg); 130 u32 net_id = msg_bc_netid(msg); 131 u32 type = msg_type(msg); 132 u32 signature = msg_node_sig(msg); 133 int addr_mismatch; 134 int link_fully_up; 135 136 media_addr.broadcast = 1; 137 b_ptr->media->msg2addr(&media_addr, msg_media_addr(msg)); 138 kfree_skb(buf); 139 140 /* Ensure message from node is valid and communication is permitted */ 141 if (net_id != tipc_net_id) 142 return; 143 if (media_addr.broadcast) 144 return; 145 if (!tipc_addr_domain_valid(dest)) 146 return; 147 if (!tipc_addr_node_valid(orig)) 148 return; 149 if (orig == tipc_own_addr) { 150 if (memcmp(&media_addr, &b_ptr->addr, sizeof(media_addr))) 151 disc_dupl_alert(b_ptr, tipc_own_addr, &media_addr); 152 return; 153 } 154 if (!tipc_in_scope(dest, tipc_own_addr)) 155 return; 156 if (!tipc_in_scope(b_ptr->link_req->domain, orig)) 157 return; 158 159 /* Locate structure corresponding to requesting node */ 160 n_ptr = tipc_node_find(orig); 161 if (!n_ptr) { 162 n_ptr = tipc_node_create(orig); 163 if (!n_ptr) 164 return; 165 } 166 tipc_node_lock(n_ptr); 167 168 /* Prepare to validate requesting node's signature and media address */ 169 link = n_ptr->links[b_ptr->identity]; 170 addr_mismatch = (link != NULL) && 171 memcmp(&link->media_addr, &media_addr, sizeof(media_addr)); 172 173 /* 174 * Ensure discovery message's signature is correct 175 * 176 * If signature is incorrect and there is no working link to the node, 177 * accept the new signature but invalidate all existing links to the 178 * node so they won't re-activate without a new discovery message. 179 * 180 * If signature is incorrect and the requested link to the node is 181 * working, accept the new signature. (This is an instance of delayed 182 * rediscovery, where a link endpoint was able to re-establish contact 183 * with its peer endpoint on a node that rebooted before receiving a 184 * discovery message from that node.) 185 * 186 * If signature is incorrect and there is a working link to the node 187 * that is not the requested link, reject the request (must be from 188 * a duplicate node). 189 */ 190 if (signature != n_ptr->signature) { 191 if (n_ptr->working_links == 0) { 192 struct tipc_link *curr_link; 193 int i; 194 195 for (i = 0; i < MAX_BEARERS; i++) { 196 curr_link = n_ptr->links[i]; 197 if (curr_link) { 198 memset(&curr_link->media_addr, 0, 199 sizeof(media_addr)); 200 tipc_link_reset(curr_link); 201 } 202 } 203 addr_mismatch = (link != NULL); 204 } else if (tipc_link_is_up(link) && !addr_mismatch) { 205 /* delayed rediscovery */ 206 } else { 207 disc_dupl_alert(b_ptr, orig, &media_addr); 208 tipc_node_unlock(n_ptr); 209 return; 210 } 211 n_ptr->signature = signature; 212 } 213 214 /* 215 * Ensure requesting node's media address is correct 216 * 217 * If media address doesn't match and the link is working, reject the 218 * request (must be from a duplicate node). 219 * 220 * If media address doesn't match and the link is not working, accept 221 * the new media address and reset the link to ensure it starts up 222 * cleanly. 223 */ 224 225 if (addr_mismatch) { 226 if (tipc_link_is_up(link)) { 227 disc_dupl_alert(b_ptr, orig, &media_addr); 228 tipc_node_unlock(n_ptr); 229 return; 230 } else { 231 memcpy(&link->media_addr, &media_addr, 232 sizeof(media_addr)); 233 tipc_link_reset(link); 234 } 235 } 236 237 /* Create a link endpoint for this bearer, if necessary */ 238 if (!link) { 239 link = tipc_link_create(n_ptr, b_ptr, &media_addr); 240 if (!link) { 241 tipc_node_unlock(n_ptr); 242 return; 243 } 244 } 245 246 /* Accept discovery message & send response, if necessary */ 247 link_fully_up = link_working_working(link); 248 249 if ((type == DSC_REQ_MSG) && !link_fully_up && !b_ptr->blocked) { 250 rbuf = tipc_disc_init_msg(DSC_RESP_MSG, orig, b_ptr); 251 if (rbuf) { 252 b_ptr->media->send_msg(rbuf, b_ptr, &media_addr); 253 kfree_skb(rbuf); 254 } 255 } 256 257 tipc_node_unlock(n_ptr); 258 } 259 260 /** 261 * disc_update - update frequency of periodic link setup requests 262 * @req: ptr to link request structure 263 * 264 * Reinitiates discovery process if discovery object has no associated nodes 265 * and is either not currently searching or is searching at a slow rate 266 */ 267 268 static void disc_update(struct tipc_link_req *req) 269 { 270 if (!req->num_nodes) { 271 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) || 272 (req->timer_intv > TIPC_LINK_REQ_FAST)) { 273 req->timer_intv = TIPC_LINK_REQ_INIT; 274 k_start_timer(&req->timer, req->timer_intv); 275 } 276 } 277 } 278 279 /** 280 * tipc_disc_add_dest - increment set of discovered nodes 281 * @req: ptr to link request structure 282 */ 283 284 void tipc_disc_add_dest(struct tipc_link_req *req) 285 { 286 req->num_nodes++; 287 } 288 289 /** 290 * tipc_disc_remove_dest - decrement set of discovered nodes 291 * @req: ptr to link request structure 292 */ 293 294 void tipc_disc_remove_dest(struct tipc_link_req *req) 295 { 296 req->num_nodes--; 297 disc_update(req); 298 } 299 300 /** 301 * disc_send_msg - send link setup request message 302 * @req: ptr to link request structure 303 */ 304 305 static void disc_send_msg(struct tipc_link_req *req) 306 { 307 if (!req->bearer->blocked) 308 tipc_bearer_send(req->bearer, req->buf, &req->dest); 309 } 310 311 /** 312 * disc_timeout - send a periodic link setup request 313 * @req: ptr to link request structure 314 * 315 * Called whenever a link setup request timer associated with a bearer expires. 316 */ 317 318 static void disc_timeout(struct tipc_link_req *req) 319 { 320 int max_delay; 321 322 spin_lock_bh(&req->bearer->lock); 323 324 /* Stop searching if only desired node has been found */ 325 326 if (tipc_node(req->domain) && req->num_nodes) { 327 req->timer_intv = TIPC_LINK_REQ_INACTIVE; 328 goto exit; 329 } 330 331 /* 332 * Send discovery message, then update discovery timer 333 * 334 * Keep doubling time between requests until limit is reached; 335 * hold at fast polling rate if don't have any associated nodes, 336 * otherwise hold at slow polling rate 337 */ 338 339 disc_send_msg(req); 340 341 req->timer_intv *= 2; 342 if (req->num_nodes) 343 max_delay = TIPC_LINK_REQ_SLOW; 344 else 345 max_delay = TIPC_LINK_REQ_FAST; 346 if (req->timer_intv > max_delay) 347 req->timer_intv = max_delay; 348 349 k_start_timer(&req->timer, req->timer_intv); 350 exit: 351 spin_unlock_bh(&req->bearer->lock); 352 } 353 354 /** 355 * tipc_disc_create - create object to send periodic link setup requests 356 * @b_ptr: ptr to bearer issuing requests 357 * @dest: destination address for request messages 358 * @dest_domain: network domain to which links can be established 359 * 360 * Returns 0 if successful, otherwise -errno. 361 */ 362 363 int tipc_disc_create(struct tipc_bearer *b_ptr, 364 struct tipc_media_addr *dest, u32 dest_domain) 365 { 366 struct tipc_link_req *req; 367 368 req = kmalloc(sizeof(*req), GFP_ATOMIC); 369 if (!req) 370 return -ENOMEM; 371 372 req->buf = tipc_disc_init_msg(DSC_REQ_MSG, dest_domain, b_ptr); 373 if (!req->buf) { 374 kfree(req); 375 return -ENOMSG; 376 } 377 378 memcpy(&req->dest, dest, sizeof(*dest)); 379 req->bearer = b_ptr; 380 req->domain = dest_domain; 381 req->num_nodes = 0; 382 req->timer_intv = TIPC_LINK_REQ_INIT; 383 k_init_timer(&req->timer, (Handler)disc_timeout, (unsigned long)req); 384 k_start_timer(&req->timer, req->timer_intv); 385 b_ptr->link_req = req; 386 disc_send_msg(req); 387 return 0; 388 } 389 390 /** 391 * tipc_disc_delete - destroy object sending periodic link setup requests 392 * @req: ptr to link request structure 393 */ 394 395 void tipc_disc_delete(struct tipc_link_req *req) 396 { 397 k_cancel_timer(&req->timer); 398 k_term_timer(&req->timer); 399 kfree_skb(req->buf); 400 kfree(req); 401 } 402 403