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