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 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 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_dest_domain(msg, dest_domain); 86 msg_set_bc_netid(msg, tipc_net_id); 87 msg_set_media_addr(msg, &b_ptr->addr); 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 99 static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr, 100 struct tipc_media_addr *media_addr) 101 { 102 char node_addr_str[16]; 103 char media_addr_str[64]; 104 struct print_buf pb; 105 106 tipc_addr_string_fill(node_addr_str, node_addr); 107 tipc_printbuf_init(&pb, media_addr_str, sizeof(media_addr_str)); 108 tipc_media_addr_printf(&pb, media_addr); 109 tipc_printbuf_validate(&pb); 110 warn("Duplicate %s using %s seen on <%s>\n", 111 node_addr_str, media_addr_str, b_ptr->name); 112 } 113 114 /** 115 * tipc_disc_recv_msg - handle incoming link setup message (request or response) 116 * @buf: buffer containing message 117 * @b_ptr: bearer that message arrived on 118 */ 119 120 void tipc_disc_recv_msg(struct sk_buff *buf, struct tipc_bearer *b_ptr) 121 { 122 struct tipc_node *n_ptr; 123 struct link *link; 124 struct tipc_media_addr media_addr, *addr; 125 struct sk_buff *rbuf; 126 struct tipc_msg *msg = buf_msg(buf); 127 u32 dest = msg_dest_domain(msg); 128 u32 orig = msg_prevnode(msg); 129 u32 net_id = msg_bc_netid(msg); 130 u32 type = msg_type(msg); 131 int link_fully_up; 132 133 msg_get_media_addr(msg, &media_addr); 134 buf_discard(buf); 135 136 /* Validate discovery message from requesting node */ 137 if (net_id != tipc_net_id) 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 /* Don't talk to neighbor during cleanup after last session */ 163 if (n_ptr->cleanup_required) { 164 tipc_node_unlock(n_ptr); 165 return; 166 } 167 168 link = n_ptr->links[b_ptr->identity]; 169 170 /* Create a link endpoint for this bearer, if necessary */ 171 if (!link) { 172 link = tipc_link_create(n_ptr, b_ptr, &media_addr); 173 if (!link) { 174 tipc_node_unlock(n_ptr); 175 return; 176 } 177 } 178 179 /* 180 * Ensure requesting node's media address is correct 181 * 182 * If media address doesn't match and the link is working, reject the 183 * request (must be from a duplicate node). 184 * 185 * If media address doesn't match and the link is not working, accept 186 * the new media address and reset the link to ensure it starts up 187 * cleanly. 188 */ 189 addr = &link->media_addr; 190 if (memcmp(addr, &media_addr, sizeof(*addr))) { 191 if (tipc_link_is_up(link) || (!link->started)) { 192 disc_dupl_alert(b_ptr, orig, &media_addr); 193 tipc_node_unlock(n_ptr); 194 return; 195 } 196 warn("Resetting link <%s>, peer interface address changed\n", 197 link->name); 198 memcpy(addr, &media_addr, sizeof(*addr)); 199 tipc_link_reset(link); 200 } 201 202 /* Accept discovery message & send response, if necessary */ 203 link_fully_up = link_working_working(link); 204 205 if ((type == DSC_REQ_MSG) && !link_fully_up && !b_ptr->blocked) { 206 rbuf = tipc_disc_init_msg(DSC_RESP_MSG, orig, b_ptr); 207 if (rbuf) { 208 b_ptr->media->send_msg(rbuf, b_ptr, &media_addr); 209 buf_discard(rbuf); 210 } 211 } 212 213 tipc_node_unlock(n_ptr); 214 } 215 216 /** 217 * disc_update - update frequency of periodic link setup requests 218 * @req: ptr to link request structure 219 * 220 * Reinitiates discovery process if discovery object has no associated nodes 221 * and is either not currently searching or is searching at a slow rate 222 */ 223 224 static void disc_update(struct link_req *req) 225 { 226 if (!req->num_nodes) { 227 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) || 228 (req->timer_intv > TIPC_LINK_REQ_FAST)) { 229 req->timer_intv = TIPC_LINK_REQ_INIT; 230 k_start_timer(&req->timer, req->timer_intv); 231 } 232 } 233 } 234 235 /** 236 * tipc_disc_add_dest - increment set of discovered nodes 237 * @req: ptr to link request structure 238 */ 239 240 void tipc_disc_add_dest(struct link_req *req) 241 { 242 req->num_nodes++; 243 } 244 245 /** 246 * tipc_disc_remove_dest - decrement set of discovered nodes 247 * @req: ptr to link request structure 248 */ 249 250 void tipc_disc_remove_dest(struct link_req *req) 251 { 252 req->num_nodes--; 253 disc_update(req); 254 } 255 256 /** 257 * disc_send_msg - send link setup request message 258 * @req: ptr to link request structure 259 */ 260 261 static void disc_send_msg(struct link_req *req) 262 { 263 if (!req->bearer->blocked) 264 tipc_bearer_send(req->bearer, req->buf, &req->dest); 265 } 266 267 /** 268 * disc_timeout - send a periodic link setup request 269 * @req: ptr to link request structure 270 * 271 * Called whenever a link setup request timer associated with a bearer expires. 272 */ 273 274 static void disc_timeout(struct link_req *req) 275 { 276 int max_delay; 277 278 spin_lock_bh(&req->bearer->lock); 279 280 /* Stop searching if only desired node has been found */ 281 282 if (tipc_node(req->domain) && req->num_nodes) { 283 req->timer_intv = TIPC_LINK_REQ_INACTIVE; 284 goto exit; 285 } 286 287 /* 288 * Send discovery message, then update discovery timer 289 * 290 * Keep doubling time between requests until limit is reached; 291 * hold at fast polling rate if don't have any associated nodes, 292 * otherwise hold at slow polling rate 293 */ 294 295 disc_send_msg(req); 296 297 req->timer_intv *= 2; 298 if (req->num_nodes) 299 max_delay = TIPC_LINK_REQ_SLOW; 300 else 301 max_delay = TIPC_LINK_REQ_FAST; 302 if (req->timer_intv > max_delay) 303 req->timer_intv = max_delay; 304 305 k_start_timer(&req->timer, req->timer_intv); 306 exit: 307 spin_unlock_bh(&req->bearer->lock); 308 } 309 310 /** 311 * tipc_disc_create - create object to send periodic link setup requests 312 * @b_ptr: ptr to bearer issuing requests 313 * @dest: destination address for request messages 314 * @dest_domain: network domain to which links can be established 315 * 316 * Returns 0 if successful, otherwise -errno. 317 */ 318 319 int tipc_disc_create(struct tipc_bearer *b_ptr, 320 struct tipc_media_addr *dest, u32 dest_domain) 321 { 322 struct link_req *req; 323 324 req = kmalloc(sizeof(*req), GFP_ATOMIC); 325 if (!req) 326 return -ENOMEM; 327 328 req->buf = tipc_disc_init_msg(DSC_REQ_MSG, dest_domain, b_ptr); 329 if (!req->buf) { 330 kfree(req); 331 return -ENOMSG; 332 } 333 334 memcpy(&req->dest, dest, sizeof(*dest)); 335 req->bearer = b_ptr; 336 req->domain = dest_domain; 337 req->num_nodes = 0; 338 req->timer_intv = TIPC_LINK_REQ_INIT; 339 k_init_timer(&req->timer, (Handler)disc_timeout, (unsigned long)req); 340 k_start_timer(&req->timer, req->timer_intv); 341 b_ptr->link_req = req; 342 disc_send_msg(req); 343 return 0; 344 } 345 346 /** 347 * tipc_disc_delete - destroy object sending periodic link setup requests 348 * @req: ptr to link request structure 349 */ 350 351 void tipc_disc_delete(struct link_req *req) 352 { 353 k_cancel_timer(&req->timer); 354 k_term_timer(&req->timer); 355 buf_discard(req->buf); 356 kfree(req); 357 } 358 359