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