1 /* 2 * net/tipc/discover.c 3 * 4 * Copyright (c) 2003-2006, 2014-2015, 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 "node.h" 39 #include "discover.h" 40 41 /* min delay during bearer start up */ 42 #define TIPC_LINK_REQ_INIT msecs_to_jiffies(125) 43 /* max delay if bearer has no links */ 44 #define TIPC_LINK_REQ_FAST msecs_to_jiffies(1000) 45 /* max delay if bearer has links */ 46 #define TIPC_LINK_REQ_SLOW msecs_to_jiffies(60000) 47 /* indicates no timer in use */ 48 #define TIPC_LINK_REQ_INACTIVE 0xffffffff 49 50 /** 51 * struct tipc_link_req - information about an ongoing link setup request 52 * @bearer_id: identity of bearer issuing requests 53 * @net: network namespace instance 54 * @dest: destination address for request messages 55 * @domain: network domain to which links can be established 56 * @num_nodes: number of nodes currently discovered (i.e. with an active link) 57 * @lock: spinlock for controlling access to requests 58 * @buf: request message to be (repeatedly) sent 59 * @timer: timer governing period between requests 60 * @timer_intv: current interval between requests (in ms) 61 */ 62 struct tipc_link_req { 63 u32 bearer_id; 64 struct tipc_media_addr dest; 65 struct net *net; 66 u32 domain; 67 int num_nodes; 68 spinlock_t lock; 69 struct sk_buff *buf; 70 struct timer_list timer; 71 unsigned long timer_intv; 72 }; 73 74 /** 75 * tipc_disc_init_msg - initialize a link setup message 76 * @net: the applicable net namespace 77 * @type: message type (request or response) 78 * @b_ptr: ptr to bearer issuing message 79 */ 80 static void tipc_disc_init_msg(struct net *net, struct sk_buff *buf, u32 type, 81 struct tipc_bearer *b_ptr) 82 { 83 struct tipc_net *tn = net_generic(net, tipc_net_id); 84 struct tipc_msg *msg; 85 u32 dest_domain = b_ptr->domain; 86 87 msg = buf_msg(buf); 88 tipc_msg_init(tn->own_addr, msg, LINK_CONFIG, type, 89 MAX_H_SIZE, dest_domain); 90 msg_set_non_seq(msg, 1); 91 msg_set_node_sig(msg, tn->random); 92 msg_set_node_capabilities(msg, 0); 93 msg_set_dest_domain(msg, dest_domain); 94 msg_set_bc_netid(msg, tn->net_id); 95 b_ptr->media->addr2msg(msg_media_addr(msg), &b_ptr->addr); 96 } 97 98 /** 99 * disc_dupl_alert - issue node address duplication alert 100 * @b_ptr: pointer to bearer detecting duplication 101 * @node_addr: duplicated node address 102 * @media_addr: media address advertised by duplicated node 103 */ 104 static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr, 105 struct tipc_media_addr *media_addr) 106 { 107 char node_addr_str[16]; 108 char media_addr_str[64]; 109 110 tipc_addr_string_fill(node_addr_str, node_addr); 111 tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str), 112 media_addr); 113 pr_warn("Duplicate %s using %s seen on <%s>\n", node_addr_str, 114 media_addr_str, b_ptr->name); 115 } 116 117 /** 118 * tipc_disc_rcv - handle incoming discovery message (request or response) 119 * @net: the applicable net namespace 120 * @buf: buffer containing message 121 * @bearer: bearer that message arrived on 122 */ 123 void tipc_disc_rcv(struct net *net, struct sk_buff *skb, 124 struct tipc_bearer *bearer) 125 { 126 struct tipc_net *tn = net_generic(net, tipc_net_id); 127 struct tipc_media_addr maddr; 128 struct sk_buff *rskb; 129 struct tipc_msg *hdr = buf_msg(skb); 130 u32 ddom = msg_dest_domain(hdr); 131 u32 onode = msg_prevnode(hdr); 132 u32 net_id = msg_bc_netid(hdr); 133 u32 mtyp = msg_type(hdr); 134 u32 signature = msg_node_sig(hdr); 135 u16 caps = msg_node_capabilities(hdr); 136 bool respond = false; 137 bool dupl_addr = false; 138 139 bearer->media->msg2addr(bearer, &maddr, msg_media_addr(hdr)); 140 kfree_skb(skb); 141 142 /* Ensure message from node is valid and communication is permitted */ 143 if (net_id != tn->net_id) 144 return; 145 if (maddr.broadcast) 146 return; 147 if (!tipc_addr_domain_valid(ddom)) 148 return; 149 if (!tipc_addr_node_valid(onode)) 150 return; 151 152 if (in_own_node(net, onode)) { 153 if (memcmp(&maddr, &bearer->addr, sizeof(maddr))) 154 disc_dupl_alert(bearer, tn->own_addr, &maddr); 155 return; 156 } 157 if (!tipc_in_scope(ddom, tn->own_addr)) 158 return; 159 if (!tipc_in_scope(bearer->domain, onode)) 160 return; 161 162 tipc_node_check_dest(net, onode, bearer, caps, signature, 163 &maddr, &respond, &dupl_addr); 164 if (dupl_addr) 165 disc_dupl_alert(bearer, onode, &maddr); 166 167 /* Send response, if necessary */ 168 if (respond && (mtyp == DSC_REQ_MSG)) { 169 rskb = tipc_buf_acquire(MAX_H_SIZE); 170 if (rskb) { 171 tipc_disc_init_msg(net, rskb, DSC_RESP_MSG, bearer); 172 tipc_bearer_send(net, bearer->identity, rskb, &maddr); 173 kfree_skb(rskb); 174 } 175 } 176 } 177 178 /** 179 * disc_update - update frequency of periodic link setup requests 180 * @req: ptr to link request structure 181 * 182 * Reinitiates discovery process if discovery object has no associated nodes 183 * and is either not currently searching or is searching at a slow rate 184 */ 185 static void disc_update(struct tipc_link_req *req) 186 { 187 if (!req->num_nodes) { 188 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) || 189 (req->timer_intv > TIPC_LINK_REQ_FAST)) { 190 req->timer_intv = TIPC_LINK_REQ_INIT; 191 mod_timer(&req->timer, jiffies + req->timer_intv); 192 } 193 } 194 } 195 196 /** 197 * tipc_disc_add_dest - increment set of discovered nodes 198 * @req: ptr to link request structure 199 */ 200 void tipc_disc_add_dest(struct tipc_link_req *req) 201 { 202 spin_lock_bh(&req->lock); 203 req->num_nodes++; 204 spin_unlock_bh(&req->lock); 205 } 206 207 /** 208 * tipc_disc_remove_dest - decrement set of discovered nodes 209 * @req: ptr to link request structure 210 */ 211 void tipc_disc_remove_dest(struct tipc_link_req *req) 212 { 213 spin_lock_bh(&req->lock); 214 req->num_nodes--; 215 disc_update(req); 216 spin_unlock_bh(&req->lock); 217 } 218 219 /** 220 * disc_timeout - send a periodic link setup request 221 * @data: ptr to link request structure 222 * 223 * Called whenever a link setup request timer associated with a bearer expires. 224 */ 225 static void disc_timeout(unsigned long data) 226 { 227 struct tipc_link_req *req = (struct tipc_link_req *)data; 228 int max_delay; 229 230 spin_lock_bh(&req->lock); 231 232 /* Stop searching if only desired node has been found */ 233 if (tipc_node(req->domain) && req->num_nodes) { 234 req->timer_intv = TIPC_LINK_REQ_INACTIVE; 235 goto exit; 236 } 237 238 /* 239 * Send discovery message, then update discovery timer 240 * 241 * Keep doubling time between requests until limit is reached; 242 * hold at fast polling rate if don't have any associated nodes, 243 * otherwise hold at slow polling rate 244 */ 245 tipc_bearer_send(req->net, req->bearer_id, req->buf, &req->dest); 246 247 248 req->timer_intv *= 2; 249 if (req->num_nodes) 250 max_delay = TIPC_LINK_REQ_SLOW; 251 else 252 max_delay = TIPC_LINK_REQ_FAST; 253 if (req->timer_intv > max_delay) 254 req->timer_intv = max_delay; 255 256 mod_timer(&req->timer, jiffies + req->timer_intv); 257 exit: 258 spin_unlock_bh(&req->lock); 259 } 260 261 /** 262 * tipc_disc_create - create object to send periodic link setup requests 263 * @net: the applicable net namespace 264 * @b_ptr: ptr to bearer issuing requests 265 * @dest: destination address for request messages 266 * @dest_domain: network domain to which links can be established 267 * 268 * Returns 0 if successful, otherwise -errno. 269 */ 270 int tipc_disc_create(struct net *net, struct tipc_bearer *b_ptr, 271 struct tipc_media_addr *dest) 272 { 273 struct tipc_link_req *req; 274 275 req = kmalloc(sizeof(*req), GFP_ATOMIC); 276 if (!req) 277 return -ENOMEM; 278 req->buf = tipc_buf_acquire(MAX_H_SIZE); 279 if (!req->buf) { 280 kfree(req); 281 return -ENOMEM; 282 } 283 284 tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b_ptr); 285 memcpy(&req->dest, dest, sizeof(*dest)); 286 req->net = net; 287 req->bearer_id = b_ptr->identity; 288 req->domain = b_ptr->domain; 289 req->num_nodes = 0; 290 req->timer_intv = TIPC_LINK_REQ_INIT; 291 spin_lock_init(&req->lock); 292 setup_timer(&req->timer, disc_timeout, (unsigned long)req); 293 mod_timer(&req->timer, jiffies + req->timer_intv); 294 b_ptr->link_req = req; 295 tipc_bearer_send(net, req->bearer_id, req->buf, &req->dest); 296 return 0; 297 } 298 299 /** 300 * tipc_disc_delete - destroy object sending periodic link setup requests 301 * @req: ptr to link request structure 302 */ 303 void tipc_disc_delete(struct tipc_link_req *req) 304 { 305 del_timer_sync(&req->timer); 306 kfree_skb(req->buf); 307 kfree(req); 308 } 309 310 /** 311 * tipc_disc_reset - reset object to send periodic link setup requests 312 * @net: the applicable net namespace 313 * @b_ptr: ptr to bearer issuing requests 314 * @dest_domain: network domain to which links can be established 315 */ 316 void tipc_disc_reset(struct net *net, struct tipc_bearer *b_ptr) 317 { 318 struct tipc_link_req *req = b_ptr->link_req; 319 320 spin_lock_bh(&req->lock); 321 tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b_ptr); 322 req->net = net; 323 req->bearer_id = b_ptr->identity; 324 req->domain = b_ptr->domain; 325 req->num_nodes = 0; 326 req->timer_intv = TIPC_LINK_REQ_INIT; 327 mod_timer(&req->timer, jiffies + req->timer_intv); 328 tipc_bearer_send(net, req->bearer_id, req->buf, &req->dest); 329 spin_unlock_bh(&req->lock); 330 } 331