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