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 * @num_nodes: number of nodes currently discovered (i.e. with an active link) 52 * @lock: spinlock for controlling access to requests 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 int num_nodes; 61 spinlock_t lock; 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 * @b_ptr: ptr to bearer issuing message 71 */ 72 static struct sk_buff *tipc_disc_init_msg(u32 type, struct tipc_bearer *b_ptr) 73 { 74 struct sk_buff *buf = tipc_buf_acquire(INT_H_SIZE); 75 struct tipc_msg *msg; 76 u32 dest_domain = b_ptr->domain; 77 78 if (buf) { 79 msg = buf_msg(buf); 80 tipc_msg_init(msg, LINK_CONFIG, type, INT_H_SIZE, dest_domain); 81 msg_set_non_seq(msg, 1); 82 msg_set_node_sig(msg, tipc_random); 83 msg_set_dest_domain(msg, dest_domain); 84 msg_set_bc_netid(msg, tipc_net_id); 85 b_ptr->media->addr2msg(&b_ptr->addr, msg_media_addr(msg)); 86 } 87 return buf; 88 } 89 90 /** 91 * disc_dupl_alert - issue node address duplication alert 92 * @b_ptr: pointer to bearer detecting duplication 93 * @node_addr: duplicated node address 94 * @media_addr: media address advertised by duplicated node 95 */ 96 static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr, 97 struct tipc_media_addr *media_addr) 98 { 99 char node_addr_str[16]; 100 char media_addr_str[64]; 101 102 tipc_addr_string_fill(node_addr_str, node_addr); 103 tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str), 104 media_addr); 105 pr_warn("Duplicate %s using %s seen on <%s>\n", node_addr_str, 106 media_addr_str, b_ptr->name); 107 } 108 109 /** 110 * tipc_disc_rcv - handle incoming link setup message (request or response) 111 * @buf: buffer containing message 112 * @b_ptr: bearer that message arrived on 113 */ 114 void tipc_disc_rcv(struct sk_buff *buf, struct tipc_bearer *b_ptr) 115 { 116 struct tipc_node *n_ptr; 117 struct tipc_link *link; 118 struct tipc_media_addr media_addr; 119 struct sk_buff *rbuf; 120 struct tipc_msg *msg = buf_msg(buf); 121 u32 dest = msg_dest_domain(msg); 122 u32 orig = msg_prevnode(msg); 123 u32 net_id = msg_bc_netid(msg); 124 u32 type = msg_type(msg); 125 u32 signature = msg_node_sig(msg); 126 int addr_mismatch; 127 int link_fully_up; 128 129 media_addr.broadcast = 1; 130 b_ptr->media->msg2addr(b_ptr, &media_addr, msg_media_addr(msg)); 131 kfree_skb(buf); 132 133 /* Ensure message from node is valid and communication is permitted */ 134 if (net_id != tipc_net_id) 135 return; 136 if (media_addr.broadcast) 137 return; 138 if (!tipc_addr_domain_valid(dest)) 139 return; 140 if (!tipc_addr_node_valid(orig)) 141 return; 142 if (orig == tipc_own_addr) { 143 if (memcmp(&media_addr, &b_ptr->addr, sizeof(media_addr))) 144 disc_dupl_alert(b_ptr, tipc_own_addr, &media_addr); 145 return; 146 } 147 if (!tipc_in_scope(dest, tipc_own_addr)) 148 return; 149 if (!tipc_in_scope(b_ptr->domain, orig)) 150 return; 151 152 /* Locate structure corresponding to requesting node */ 153 n_ptr = tipc_node_find(orig); 154 if (!n_ptr) { 155 n_ptr = tipc_node_create(orig); 156 if (!n_ptr) 157 return; 158 } 159 tipc_node_lock(n_ptr); 160 161 /* Prepare to validate requesting node's signature and media address */ 162 link = n_ptr->links[b_ptr->identity]; 163 addr_mismatch = (link != NULL) && 164 memcmp(&link->media_addr, &media_addr, sizeof(media_addr)); 165 166 /* 167 * Ensure discovery message's signature is correct 168 * 169 * If signature is incorrect and there is no working link to the node, 170 * accept the new signature but invalidate all existing links to the 171 * node so they won't re-activate without a new discovery message. 172 * 173 * If signature is incorrect and the requested link to the node is 174 * working, accept the new signature. (This is an instance of delayed 175 * rediscovery, where a link endpoint was able to re-establish contact 176 * with its peer endpoint on a node that rebooted before receiving a 177 * discovery message from that node.) 178 * 179 * If signature is incorrect and there is a working link to the node 180 * that is not the requested link, reject the request (must be from 181 * a duplicate node). 182 */ 183 if (signature != n_ptr->signature) { 184 if (n_ptr->working_links == 0) { 185 struct tipc_link *curr_link; 186 int i; 187 188 for (i = 0; i < MAX_BEARERS; i++) { 189 curr_link = n_ptr->links[i]; 190 if (curr_link) { 191 memset(&curr_link->media_addr, 0, 192 sizeof(media_addr)); 193 tipc_link_reset(curr_link); 194 } 195 } 196 addr_mismatch = (link != NULL); 197 } else if (tipc_link_is_up(link) && !addr_mismatch) { 198 /* delayed rediscovery */ 199 } else { 200 disc_dupl_alert(b_ptr, orig, &media_addr); 201 tipc_node_unlock(n_ptr); 202 return; 203 } 204 n_ptr->signature = signature; 205 } 206 207 /* 208 * Ensure requesting node's media address is correct 209 * 210 * If media address doesn't match and the link is working, reject the 211 * request (must be from a duplicate node). 212 * 213 * If media address doesn't match and the link is not working, accept 214 * the new media address and reset the link to ensure it starts up 215 * cleanly. 216 */ 217 if (addr_mismatch) { 218 if (tipc_link_is_up(link)) { 219 disc_dupl_alert(b_ptr, orig, &media_addr); 220 tipc_node_unlock(n_ptr); 221 return; 222 } else { 223 memcpy(&link->media_addr, &media_addr, 224 sizeof(media_addr)); 225 tipc_link_reset(link); 226 } 227 } 228 229 /* Create a link endpoint for this bearer, if necessary */ 230 if (!link) { 231 link = tipc_link_create(n_ptr, b_ptr, &media_addr); 232 if (!link) { 233 tipc_node_unlock(n_ptr); 234 return; 235 } 236 } 237 238 /* Accept discovery message & send response, if necessary */ 239 link_fully_up = link_working_working(link); 240 241 if ((type == DSC_REQ_MSG) && !link_fully_up) { 242 rbuf = tipc_disc_init_msg(DSC_RESP_MSG, b_ptr); 243 if (rbuf) { 244 tipc_bearer_send(b_ptr, rbuf, &media_addr); 245 kfree_skb(rbuf); 246 } 247 } 248 249 tipc_node_unlock(n_ptr); 250 } 251 252 /** 253 * disc_update - update frequency of periodic link setup requests 254 * @req: ptr to link request structure 255 * 256 * Reinitiates discovery process if discovery object has no associated nodes 257 * and is either not currently searching or is searching at a slow rate 258 */ 259 static void disc_update(struct tipc_link_req *req) 260 { 261 if (!req->num_nodes) { 262 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) || 263 (req->timer_intv > TIPC_LINK_REQ_FAST)) { 264 req->timer_intv = TIPC_LINK_REQ_INIT; 265 k_start_timer(&req->timer, req->timer_intv); 266 } 267 } 268 } 269 270 /** 271 * tipc_disc_add_dest - increment set of discovered nodes 272 * @req: ptr to link request structure 273 */ 274 void tipc_disc_add_dest(struct tipc_link_req *req) 275 { 276 spin_lock_bh(&req->lock); 277 req->num_nodes++; 278 spin_unlock_bh(&req->lock); 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 spin_lock_bh(&req->lock); 288 req->num_nodes--; 289 disc_update(req); 290 spin_unlock_bh(&req->lock); 291 } 292 293 /** 294 * disc_timeout - send a periodic link setup request 295 * @req: ptr to link request structure 296 * 297 * Called whenever a link setup request timer associated with a bearer expires. 298 */ 299 static void disc_timeout(struct tipc_link_req *req) 300 { 301 int max_delay; 302 303 spin_lock_bh(&req->lock); 304 305 /* Stop searching if only desired node has been found */ 306 if (tipc_node(req->bearer->domain) && req->num_nodes) { 307 req->timer_intv = TIPC_LINK_REQ_INACTIVE; 308 goto exit; 309 } 310 311 /* 312 * Send discovery message, then update discovery timer 313 * 314 * Keep doubling time between requests until limit is reached; 315 * hold at fast polling rate if don't have any associated nodes, 316 * otherwise hold at slow polling rate 317 */ 318 tipc_bearer_send(req->bearer, req->buf, &req->dest); 319 320 321 req->timer_intv *= 2; 322 if (req->num_nodes) 323 max_delay = TIPC_LINK_REQ_SLOW; 324 else 325 max_delay = TIPC_LINK_REQ_FAST; 326 if (req->timer_intv > max_delay) 327 req->timer_intv = max_delay; 328 329 k_start_timer(&req->timer, req->timer_intv); 330 exit: 331 spin_unlock_bh(&req->lock); 332 } 333 334 /** 335 * tipc_disc_create - create object to send periodic link setup requests 336 * @b_ptr: ptr to bearer issuing requests 337 * @dest: destination address for request messages 338 * @dest_domain: network domain to which links can be established 339 * 340 * Returns 0 if successful, otherwise -errno. 341 */ 342 int tipc_disc_create(struct tipc_bearer *b_ptr, struct tipc_media_addr *dest) 343 { 344 struct tipc_link_req *req; 345 346 req = kmalloc(sizeof(*req), GFP_ATOMIC); 347 if (!req) 348 return -ENOMEM; 349 350 req->buf = tipc_disc_init_msg(DSC_REQ_MSG, b_ptr); 351 if (!req->buf) { 352 kfree(req); 353 return -ENOMSG; 354 } 355 356 memcpy(&req->dest, dest, sizeof(*dest)); 357 req->bearer = b_ptr; 358 req->num_nodes = 0; 359 req->timer_intv = TIPC_LINK_REQ_INIT; 360 spin_lock_init(&req->lock); 361 k_init_timer(&req->timer, (Handler)disc_timeout, (unsigned long)req); 362 k_start_timer(&req->timer, req->timer_intv); 363 b_ptr->link_req = req; 364 tipc_bearer_send(req->bearer, req->buf, &req->dest); 365 return 0; 366 } 367 368 /** 369 * tipc_disc_delete - destroy object sending periodic link setup requests 370 * @req: ptr to link request structure 371 */ 372 void tipc_disc_delete(struct tipc_link_req *req) 373 { 374 k_cancel_timer(&req->timer); 375 k_term_timer(&req->timer); 376 kfree_skb(req->buf); 377 kfree(req); 378 } 379