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 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) 82 { 83 struct tipc_net *tn = net_generic(net, tipc_net_id); 84 struct tipc_msg *msg; 85 u32 dest_domain = b->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, TIPC_NODE_CAPABILITIES); 93 msg_set_dest_domain(msg, dest_domain); 94 msg_set_bc_netid(msg, tn->net_id); 95 b->media->addr2msg(msg_media_addr(msg), &b->addr); 96 } 97 98 /** 99 * disc_dupl_alert - issue node address duplication alert 100 * @b: 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, 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->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 int err; 139 140 err = bearer->media->msg2addr(bearer, &maddr, msg_media_addr(hdr)); 141 kfree_skb(skb); 142 if (err) 143 return; 144 145 /* Ensure message from node is valid and communication is permitted */ 146 if (net_id != tn->net_id) 147 return; 148 if (maddr.broadcast) 149 return; 150 if (!tipc_addr_domain_valid(ddom)) 151 return; 152 if (!tipc_addr_node_valid(onode)) 153 return; 154 155 if (in_own_node(net, onode)) { 156 if (memcmp(&maddr, &bearer->addr, sizeof(maddr))) 157 disc_dupl_alert(bearer, tn->own_addr, &maddr); 158 return; 159 } 160 if (!tipc_in_scope(ddom, tn->own_addr)) 161 return; 162 if (!tipc_in_scope(bearer->domain, onode)) 163 return; 164 165 tipc_node_check_dest(net, onode, bearer, caps, signature, 166 &maddr, &respond, &dupl_addr); 167 if (dupl_addr) 168 disc_dupl_alert(bearer, onode, &maddr); 169 170 /* Send response, if necessary */ 171 if (respond && (mtyp == DSC_REQ_MSG)) { 172 rskb = tipc_buf_acquire(MAX_H_SIZE); 173 if (!rskb) 174 return; 175 tipc_disc_init_msg(net, rskb, DSC_RESP_MSG, bearer); 176 tipc_bearer_xmit_skb(net, bearer->identity, rskb, &maddr); 177 } 178 } 179 180 /** 181 * disc_update - update frequency of periodic link setup requests 182 * @req: ptr to link request structure 183 * 184 * Reinitiates discovery process if discovery object has no associated nodes 185 * and is either not currently searching or is searching at a slow rate 186 */ 187 static void disc_update(struct tipc_link_req *req) 188 { 189 if (!req->num_nodes) { 190 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) || 191 (req->timer_intv > TIPC_LINK_REQ_FAST)) { 192 req->timer_intv = TIPC_LINK_REQ_INIT; 193 mod_timer(&req->timer, jiffies + req->timer_intv); 194 } 195 } 196 } 197 198 /** 199 * tipc_disc_add_dest - increment set of discovered nodes 200 * @req: ptr to link request structure 201 */ 202 void tipc_disc_add_dest(struct tipc_link_req *req) 203 { 204 spin_lock_bh(&req->lock); 205 req->num_nodes++; 206 spin_unlock_bh(&req->lock); 207 } 208 209 /** 210 * tipc_disc_remove_dest - decrement set of discovered nodes 211 * @req: ptr to link request structure 212 */ 213 void tipc_disc_remove_dest(struct tipc_link_req *req) 214 { 215 spin_lock_bh(&req->lock); 216 req->num_nodes--; 217 disc_update(req); 218 spin_unlock_bh(&req->lock); 219 } 220 221 /** 222 * disc_timeout - send a periodic link setup request 223 * @data: ptr to link request structure 224 * 225 * Called whenever a link setup request timer associated with a bearer expires. 226 */ 227 static void disc_timeout(unsigned long data) 228 { 229 struct tipc_link_req *req = (struct tipc_link_req *)data; 230 struct sk_buff *skb; 231 int max_delay; 232 233 spin_lock_bh(&req->lock); 234 235 /* Stop searching if only desired node has been found */ 236 if (tipc_node(req->domain) && req->num_nodes) { 237 req->timer_intv = TIPC_LINK_REQ_INACTIVE; 238 goto exit; 239 } 240 241 /* 242 * Send discovery message, then update discovery timer 243 * 244 * Keep doubling time between requests until limit is reached; 245 * hold at fast polling rate if don't have any associated nodes, 246 * otherwise hold at slow polling rate 247 */ 248 skb = skb_clone(req->buf, GFP_ATOMIC); 249 if (skb) 250 tipc_bearer_xmit_skb(req->net, req->bearer_id, skb, &req->dest); 251 req->timer_intv *= 2; 252 if (req->num_nodes) 253 max_delay = TIPC_LINK_REQ_SLOW; 254 else 255 max_delay = TIPC_LINK_REQ_FAST; 256 if (req->timer_intv > max_delay) 257 req->timer_intv = max_delay; 258 259 mod_timer(&req->timer, jiffies + req->timer_intv); 260 exit: 261 spin_unlock_bh(&req->lock); 262 } 263 264 /** 265 * tipc_disc_create - create object to send periodic link setup requests 266 * @net: the applicable net namespace 267 * @b: ptr to bearer issuing requests 268 * @dest: destination address for request messages 269 * @dest_domain: network domain to which links can be established 270 * 271 * Returns 0 if successful, otherwise -errno. 272 */ 273 int tipc_disc_create(struct net *net, struct tipc_bearer *b, 274 struct tipc_media_addr *dest, struct sk_buff **skb) 275 { 276 struct tipc_link_req *req; 277 278 req = kmalloc(sizeof(*req), GFP_ATOMIC); 279 if (!req) 280 return -ENOMEM; 281 req->buf = tipc_buf_acquire(MAX_H_SIZE); 282 if (!req->buf) { 283 kfree(req); 284 return -ENOMEM; 285 } 286 287 tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b); 288 memcpy(&req->dest, dest, sizeof(*dest)); 289 req->net = net; 290 req->bearer_id = b->identity; 291 req->domain = b->domain; 292 req->num_nodes = 0; 293 req->timer_intv = TIPC_LINK_REQ_INIT; 294 spin_lock_init(&req->lock); 295 setup_timer(&req->timer, disc_timeout, (unsigned long)req); 296 mod_timer(&req->timer, jiffies + req->timer_intv); 297 b->link_req = req; 298 *skb = skb_clone(req->buf, GFP_ATOMIC); 299 return 0; 300 } 301 302 /** 303 * tipc_disc_delete - destroy object sending periodic link setup requests 304 * @req: ptr to link request structure 305 */ 306 void tipc_disc_delete(struct tipc_link_req *req) 307 { 308 del_timer_sync(&req->timer); 309 kfree_skb(req->buf); 310 kfree(req); 311 } 312 313 /** 314 * tipc_disc_reset - reset object to send periodic link setup requests 315 * @net: the applicable net namespace 316 * @b: ptr to bearer issuing requests 317 * @dest_domain: network domain to which links can be established 318 */ 319 void tipc_disc_reset(struct net *net, struct tipc_bearer *b) 320 { 321 struct tipc_link_req *req = b->link_req; 322 struct sk_buff *skb; 323 324 spin_lock_bh(&req->lock); 325 tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b); 326 req->net = net; 327 req->bearer_id = b->identity; 328 req->domain = b->domain; 329 req->num_nodes = 0; 330 req->timer_intv = TIPC_LINK_REQ_INIT; 331 mod_timer(&req->timer, jiffies + req->timer_intv); 332 skb = skb_clone(req->buf, GFP_ATOMIC); 333 if (skb) 334 tipc_bearer_xmit_skb(net, req->bearer_id, skb, &req->dest); 335 spin_unlock_bh(&req->lock); 336 } 337