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