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 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 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 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 tipc_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 media_addr.broadcast = 1; 134 b_ptr->media->msg2addr(&media_addr, msg_media_addr(msg)); 135 buf_discard(buf); 136 137 /* Validate discovery message from requesting node */ 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 link = n_ptr->links[b_ptr->identity]; 166 167 /* Create a link endpoint for this bearer, if necessary */ 168 if (!link) { 169 link = tipc_link_create(n_ptr, b_ptr, &media_addr); 170 if (!link) { 171 tipc_node_unlock(n_ptr); 172 return; 173 } 174 } 175 176 /* 177 * Ensure requesting node's media address is correct 178 * 179 * If media address doesn't match and the link is working, reject the 180 * request (must be from a duplicate node). 181 * 182 * If media address doesn't match and the link is not working, accept 183 * the new media address and reset the link to ensure it starts up 184 * cleanly. 185 */ 186 addr = &link->media_addr; 187 if (memcmp(addr, &media_addr, sizeof(*addr))) { 188 if (tipc_link_is_up(link) || (!link->started)) { 189 disc_dupl_alert(b_ptr, orig, &media_addr); 190 tipc_node_unlock(n_ptr); 191 return; 192 } 193 warn("Resetting link <%s>, peer interface address changed\n", 194 link->name); 195 memcpy(addr, &media_addr, sizeof(*addr)); 196 tipc_link_reset(link); 197 } 198 199 /* Accept discovery message & send response, if necessary */ 200 link_fully_up = link_working_working(link); 201 202 if ((type == DSC_REQ_MSG) && !link_fully_up && !b_ptr->blocked) { 203 rbuf = tipc_disc_init_msg(DSC_RESP_MSG, orig, b_ptr); 204 if (rbuf) { 205 b_ptr->media->send_msg(rbuf, b_ptr, &media_addr); 206 buf_discard(rbuf); 207 } 208 } 209 210 tipc_node_unlock(n_ptr); 211 } 212 213 /** 214 * disc_update - update frequency of periodic link setup requests 215 * @req: ptr to link request structure 216 * 217 * Reinitiates discovery process if discovery object has no associated nodes 218 * and is either not currently searching or is searching at a slow rate 219 */ 220 221 static void disc_update(struct tipc_link_req *req) 222 { 223 if (!req->num_nodes) { 224 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) || 225 (req->timer_intv > TIPC_LINK_REQ_FAST)) { 226 req->timer_intv = TIPC_LINK_REQ_INIT; 227 k_start_timer(&req->timer, req->timer_intv); 228 } 229 } 230 } 231 232 /** 233 * tipc_disc_add_dest - increment set of discovered nodes 234 * @req: ptr to link request structure 235 */ 236 237 void tipc_disc_add_dest(struct tipc_link_req *req) 238 { 239 req->num_nodes++; 240 } 241 242 /** 243 * tipc_disc_remove_dest - decrement set of discovered nodes 244 * @req: ptr to link request structure 245 */ 246 247 void tipc_disc_remove_dest(struct tipc_link_req *req) 248 { 249 req->num_nodes--; 250 disc_update(req); 251 } 252 253 /** 254 * disc_send_msg - send link setup request message 255 * @req: ptr to link request structure 256 */ 257 258 static void disc_send_msg(struct tipc_link_req *req) 259 { 260 if (!req->bearer->blocked) 261 tipc_bearer_send(req->bearer, req->buf, &req->dest); 262 } 263 264 /** 265 * disc_timeout - send a periodic link setup request 266 * @req: ptr to link request structure 267 * 268 * Called whenever a link setup request timer associated with a bearer expires. 269 */ 270 271 static void disc_timeout(struct tipc_link_req *req) 272 { 273 int max_delay; 274 275 spin_lock_bh(&req->bearer->lock); 276 277 /* Stop searching if only desired node has been found */ 278 279 if (tipc_node(req->domain) && req->num_nodes) { 280 req->timer_intv = TIPC_LINK_REQ_INACTIVE; 281 goto exit; 282 } 283 284 /* 285 * Send discovery message, then update discovery timer 286 * 287 * Keep doubling time between requests until limit is reached; 288 * hold at fast polling rate if don't have any associated nodes, 289 * otherwise hold at slow polling rate 290 */ 291 292 disc_send_msg(req); 293 294 req->timer_intv *= 2; 295 if (req->num_nodes) 296 max_delay = TIPC_LINK_REQ_SLOW; 297 else 298 max_delay = TIPC_LINK_REQ_FAST; 299 if (req->timer_intv > max_delay) 300 req->timer_intv = max_delay; 301 302 k_start_timer(&req->timer, req->timer_intv); 303 exit: 304 spin_unlock_bh(&req->bearer->lock); 305 } 306 307 /** 308 * tipc_disc_create - create object to send periodic link setup requests 309 * @b_ptr: ptr to bearer issuing requests 310 * @dest: destination address for request messages 311 * @dest_domain: network domain to which links can be established 312 * 313 * Returns 0 if successful, otherwise -errno. 314 */ 315 316 int tipc_disc_create(struct tipc_bearer *b_ptr, 317 struct tipc_media_addr *dest, u32 dest_domain) 318 { 319 struct tipc_link_req *req; 320 321 req = kmalloc(sizeof(*req), GFP_ATOMIC); 322 if (!req) 323 return -ENOMEM; 324 325 req->buf = tipc_disc_init_msg(DSC_REQ_MSG, dest_domain, b_ptr); 326 if (!req->buf) { 327 kfree(req); 328 return -ENOMSG; 329 } 330 331 memcpy(&req->dest, dest, sizeof(*dest)); 332 req->bearer = b_ptr; 333 req->domain = dest_domain; 334 req->num_nodes = 0; 335 req->timer_intv = TIPC_LINK_REQ_INIT; 336 k_init_timer(&req->timer, (Handler)disc_timeout, (unsigned long)req); 337 k_start_timer(&req->timer, req->timer_intv); 338 b_ptr->link_req = req; 339 disc_send_msg(req); 340 return 0; 341 } 342 343 /** 344 * tipc_disc_delete - destroy object sending periodic link setup requests 345 * @req: ptr to link request structure 346 */ 347 348 void tipc_disc_delete(struct tipc_link_req *req) 349 { 350 k_cancel_timer(&req->timer); 351 k_term_timer(&req->timer); 352 buf_discard(req->buf); 353 kfree(req); 354 } 355 356