1 /* 2 * net/tipc/discover.c 3 * 4 * Copyright (c) 2003-2006, 2014-2018, 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_DISC_INIT msecs_to_jiffies(125) 43 /* max delay if bearer has no links */ 44 #define TIPC_DISC_FAST msecs_to_jiffies(1000) 45 /* max delay if bearer has links */ 46 #define TIPC_DISC_SLOW msecs_to_jiffies(60000) 47 /* indicates no timer in use */ 48 #define TIPC_DISC_INACTIVE 0xffffffff 49 50 /** 51 * struct tipc_discoverer - 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 * @skb: request message to be (repeatedly) sent 59 * @timer: timer governing period between requests 60 * @timer_intv: current interval between requests (in ms) 61 * @rcu: RCU head for deferred freeing 62 */ 63 struct tipc_discoverer { 64 u32 bearer_id; 65 struct tipc_media_addr dest; 66 struct net *net; 67 u32 domain; 68 int num_nodes; 69 spinlock_t lock; 70 struct sk_buff *skb; 71 struct timer_list timer; 72 unsigned long timer_intv; 73 struct rcu_head rcu; 74 }; 75 76 /** 77 * tipc_disc_init_msg - initialize a link setup message 78 * @net: the applicable net namespace 79 * @skb: buffer containing message 80 * @mtyp: message type (request or response) 81 * @b: ptr to bearer issuing message 82 */ 83 static void tipc_disc_init_msg(struct net *net, struct sk_buff *skb, 84 u32 mtyp, struct tipc_bearer *b) 85 { 86 struct tipc_net *tn = tipc_net(net); 87 u32 dest_domain = b->domain; 88 struct tipc_msg *hdr; 89 90 hdr = buf_msg(skb); 91 tipc_msg_init(tn->trial_addr, hdr, LINK_CONFIG, mtyp, 92 MAX_H_SIZE, dest_domain); 93 msg_set_size(hdr, MAX_H_SIZE + NODE_ID_LEN); 94 msg_set_non_seq(hdr, 1); 95 msg_set_node_sig(hdr, tn->random); 96 msg_set_node_capabilities(hdr, TIPC_NODE_CAPABILITIES); 97 msg_set_dest_domain(hdr, dest_domain); 98 msg_set_bc_netid(hdr, tn->net_id); 99 b->media->addr2msg(msg_media_addr(hdr), &b->addr); 100 msg_set_peer_net_hash(hdr, tipc_net_hash_mixes(net, tn->random)); 101 msg_set_node_id(hdr, tipc_own_id(net)); 102 } 103 104 static void tipc_disc_msg_xmit(struct net *net, u32 mtyp, u32 dst, 105 u32 src, u32 sugg_addr, 106 struct tipc_media_addr *maddr, 107 struct tipc_bearer *b) 108 { 109 struct tipc_msg *hdr; 110 struct sk_buff *skb; 111 112 skb = tipc_buf_acquire(MAX_H_SIZE + NODE_ID_LEN, GFP_ATOMIC); 113 if (!skb) 114 return; 115 hdr = buf_msg(skb); 116 tipc_disc_init_msg(net, skb, mtyp, b); 117 msg_set_sugg_node_addr(hdr, sugg_addr); 118 msg_set_dest_domain(hdr, dst); 119 tipc_bearer_xmit_skb(net, b->identity, skb, maddr); 120 } 121 122 /** 123 * disc_dupl_alert - issue node address duplication alert 124 * @b: pointer to bearer detecting duplication 125 * @node_addr: duplicated node address 126 * @media_addr: media address advertised by duplicated node 127 */ 128 static void disc_dupl_alert(struct tipc_bearer *b, u32 node_addr, 129 struct tipc_media_addr *media_addr) 130 { 131 char media_addr_str[64]; 132 133 tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str), 134 media_addr); 135 pr_warn("Duplicate %x using %s seen on <%s>\n", node_addr, 136 media_addr_str, b->name); 137 } 138 139 /* tipc_disc_addr_trial(): - handle an address uniqueness trial from peer 140 * Returns true if message should be dropped by caller, i.e., if it is a 141 * trial message or we are inside trial period. Otherwise false. 142 */ 143 static bool tipc_disc_addr_trial_msg(struct tipc_discoverer *d, 144 struct tipc_media_addr *maddr, 145 struct tipc_bearer *b, 146 u32 dst, u32 src, 147 u32 sugg_addr, 148 u8 *peer_id, 149 int mtyp) 150 { 151 struct net *net = d->net; 152 struct tipc_net *tn = tipc_net(net); 153 u32 self = tipc_own_addr(net); 154 bool trial = time_before(jiffies, tn->addr_trial_end) && !self; 155 156 if (mtyp == DSC_TRIAL_FAIL_MSG) { 157 if (!trial) 158 return true; 159 160 /* Ignore if somebody else already gave new suggestion */ 161 if (dst != tn->trial_addr) 162 return true; 163 164 /* Otherwise update trial address and restart trial period */ 165 tn->trial_addr = sugg_addr; 166 msg_set_prevnode(buf_msg(d->skb), sugg_addr); 167 tn->addr_trial_end = jiffies + msecs_to_jiffies(1000); 168 return true; 169 } 170 171 /* Apply trial address if we just left trial period */ 172 if (!trial && !self) { 173 schedule_work(&tn->work); 174 msg_set_prevnode(buf_msg(d->skb), tn->trial_addr); 175 msg_set_type(buf_msg(d->skb), DSC_REQ_MSG); 176 } 177 178 /* Accept regular link requests/responses only after trial period */ 179 if (mtyp != DSC_TRIAL_MSG) 180 return trial; 181 182 sugg_addr = tipc_node_try_addr(net, peer_id, src); 183 if (sugg_addr) 184 tipc_disc_msg_xmit(net, DSC_TRIAL_FAIL_MSG, src, 185 self, sugg_addr, maddr, b); 186 return true; 187 } 188 189 /** 190 * tipc_disc_rcv - handle incoming discovery message (request or response) 191 * @net: applicable net namespace 192 * @skb: buffer containing message 193 * @b: bearer that message arrived on 194 */ 195 void tipc_disc_rcv(struct net *net, struct sk_buff *skb, 196 struct tipc_bearer *b) 197 { 198 struct tipc_net *tn = tipc_net(net); 199 struct tipc_msg *hdr = buf_msg(skb); 200 u32 pnet_hash = msg_peer_net_hash(hdr); 201 u16 caps = msg_node_capabilities(hdr); 202 bool legacy = tn->legacy_addr_format; 203 u32 sugg = msg_sugg_node_addr(hdr); 204 u32 signature = msg_node_sig(hdr); 205 u8 peer_id[NODE_ID_LEN] = {0,}; 206 u32 dst = msg_dest_domain(hdr); 207 u32 net_id = msg_bc_netid(hdr); 208 struct tipc_media_addr maddr; 209 u32 src = msg_prevnode(hdr); 210 u32 mtyp = msg_type(hdr); 211 bool dupl_addr = false; 212 bool respond = false; 213 u32 self; 214 int err; 215 216 if (skb_linearize(skb)) { 217 kfree_skb(skb); 218 return; 219 } 220 hdr = buf_msg(skb); 221 222 if (caps & TIPC_NODE_ID128) 223 memcpy(peer_id, msg_node_id(hdr), NODE_ID_LEN); 224 else 225 sprintf(peer_id, "%x", src); 226 227 err = b->media->msg2addr(b, &maddr, msg_media_addr(hdr)); 228 kfree_skb(skb); 229 if (err || maddr.broadcast) { 230 pr_warn_ratelimited("Rcv corrupt discovery message\n"); 231 return; 232 } 233 /* Ignore discovery messages from own node */ 234 if (!memcmp(&maddr, &b->addr, sizeof(maddr))) 235 return; 236 if (net_id != tn->net_id) 237 return; 238 if (tipc_disc_addr_trial_msg(b->disc, &maddr, b, dst, 239 src, sugg, peer_id, mtyp)) 240 return; 241 self = tipc_own_addr(net); 242 243 /* Message from somebody using this node's address */ 244 if (in_own_node(net, src)) { 245 disc_dupl_alert(b, self, &maddr); 246 return; 247 } 248 if (!tipc_in_scope(legacy, dst, self)) 249 return; 250 if (!tipc_in_scope(legacy, b->domain, src)) 251 return; 252 tipc_node_check_dest(net, src, peer_id, b, caps, signature, pnet_hash, 253 &maddr, &respond, &dupl_addr); 254 if (dupl_addr) 255 disc_dupl_alert(b, src, &maddr); 256 if (!respond) 257 return; 258 if (mtyp != DSC_REQ_MSG) 259 return; 260 tipc_disc_msg_xmit(net, DSC_RESP_MSG, src, self, 0, &maddr, b); 261 } 262 263 /* tipc_disc_add_dest - increment set of discovered nodes 264 */ 265 void tipc_disc_add_dest(struct tipc_discoverer *d) 266 { 267 spin_lock_bh(&d->lock); 268 d->num_nodes++; 269 spin_unlock_bh(&d->lock); 270 } 271 272 /* tipc_disc_remove_dest - decrement set of discovered nodes 273 */ 274 void tipc_disc_remove_dest(struct tipc_discoverer *d) 275 { 276 int intv, num; 277 278 spin_lock_bh(&d->lock); 279 d->num_nodes--; 280 num = d->num_nodes; 281 intv = d->timer_intv; 282 if (!num && (intv == TIPC_DISC_INACTIVE || intv > TIPC_DISC_FAST)) { 283 d->timer_intv = TIPC_DISC_INIT; 284 mod_timer(&d->timer, jiffies + d->timer_intv); 285 } 286 spin_unlock_bh(&d->lock); 287 } 288 289 /* tipc_disc_timeout - send a periodic link setup request 290 * Called whenever a link setup request timer associated with a bearer expires. 291 * - Keep doubling time between sent request until limit is reached; 292 * - Hold at fast polling rate if we don't have any associated nodes 293 * - Otherwise hold at slow polling rate 294 */ 295 static void tipc_disc_timeout(struct timer_list *t) 296 { 297 struct tipc_discoverer *d = timer_container_of(d, t, timer); 298 struct tipc_net *tn = tipc_net(d->net); 299 struct tipc_media_addr maddr; 300 struct sk_buff *skb = NULL; 301 struct net *net = d->net; 302 u32 bearer_id; 303 304 spin_lock_bh(&d->lock); 305 306 /* Stop searching if only desired node has been found */ 307 if (tipc_node(d->domain) && d->num_nodes) { 308 d->timer_intv = TIPC_DISC_INACTIVE; 309 goto exit; 310 } 311 312 /* Did we just leave trial period ? */ 313 if (!time_before(jiffies, tn->addr_trial_end) && !tipc_own_addr(net)) { 314 mod_timer(&d->timer, jiffies + TIPC_DISC_INIT); 315 spin_unlock_bh(&d->lock); 316 schedule_work(&tn->work); 317 return; 318 } 319 320 /* Adjust timeout interval according to discovery phase */ 321 if (time_before(jiffies, tn->addr_trial_end)) { 322 d->timer_intv = TIPC_DISC_INIT; 323 } else { 324 d->timer_intv *= 2; 325 if (d->num_nodes && d->timer_intv > TIPC_DISC_SLOW) 326 d->timer_intv = TIPC_DISC_SLOW; 327 else if (!d->num_nodes && d->timer_intv > TIPC_DISC_FAST) 328 d->timer_intv = TIPC_DISC_FAST; 329 msg_set_type(buf_msg(d->skb), DSC_REQ_MSG); 330 msg_set_prevnode(buf_msg(d->skb), tn->trial_addr); 331 } 332 333 mod_timer(&d->timer, jiffies + d->timer_intv); 334 memcpy(&maddr, &d->dest, sizeof(maddr)); 335 skb = skb_clone(d->skb, GFP_ATOMIC); 336 bearer_id = d->bearer_id; 337 exit: 338 spin_unlock_bh(&d->lock); 339 if (skb) 340 tipc_bearer_xmit_skb(net, bearer_id, skb, &maddr); 341 } 342 343 /** 344 * tipc_disc_create - create object to send periodic link setup requests 345 * @net: the applicable net namespace 346 * @b: ptr to bearer issuing requests 347 * @dest: destination address for request messages 348 * @skb: pointer to created frame 349 * 350 * Return: 0 if successful, otherwise -errno. 351 */ 352 int tipc_disc_create(struct net *net, struct tipc_bearer *b, 353 struct tipc_media_addr *dest, struct sk_buff **skb) 354 { 355 struct tipc_net *tn = tipc_net(net); 356 struct tipc_discoverer *d; 357 358 d = kmalloc_obj(*d, GFP_ATOMIC); 359 if (!d) 360 return -ENOMEM; 361 d->skb = tipc_buf_acquire(MAX_H_SIZE + NODE_ID_LEN, GFP_ATOMIC); 362 if (!d->skb) { 363 kfree(d); 364 return -ENOMEM; 365 } 366 tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b); 367 368 /* Do we need an address trial period first ? */ 369 if (!tipc_own_addr(net)) { 370 tn->addr_trial_end = jiffies + msecs_to_jiffies(1000); 371 msg_set_type(buf_msg(d->skb), DSC_TRIAL_MSG); 372 } 373 memcpy(&d->dest, dest, sizeof(*dest)); 374 d->net = net; 375 d->bearer_id = b->identity; 376 d->domain = b->domain; 377 d->num_nodes = 0; 378 d->timer_intv = TIPC_DISC_INIT; 379 spin_lock_init(&d->lock); 380 timer_setup(&d->timer, tipc_disc_timeout, 0); 381 mod_timer(&d->timer, jiffies + d->timer_intv); 382 b->disc = d; 383 *skb = skb_clone(d->skb, GFP_ATOMIC); 384 return 0; 385 } 386 387 static void tipc_disc_free_rcu(struct rcu_head *rp) 388 { 389 struct tipc_discoverer *d = container_of(rp, struct tipc_discoverer, 390 rcu); 391 392 kfree_skb(d->skb); 393 kfree(d); 394 } 395 396 /** 397 * tipc_disc_delete - destroy object sending periodic link setup requests 398 * @d: ptr to link dest structure 399 */ 400 void tipc_disc_delete(struct tipc_discoverer *d) 401 { 402 timer_shutdown_sync(&d->timer); 403 call_rcu(&d->rcu, tipc_disc_free_rcu); 404 } 405 406 /** 407 * tipc_disc_reset - reset object to send periodic link setup requests 408 * @net: the applicable net namespace 409 * @b: ptr to bearer issuing requests 410 */ 411 void tipc_disc_reset(struct net *net, struct tipc_bearer *b) 412 { 413 struct tipc_discoverer *d = b->disc; 414 struct tipc_media_addr maddr; 415 struct sk_buff *skb; 416 417 spin_lock_bh(&d->lock); 418 tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b); 419 d->net = net; 420 d->bearer_id = b->identity; 421 d->domain = b->domain; 422 d->num_nodes = 0; 423 d->timer_intv = TIPC_DISC_INIT; 424 memcpy(&maddr, &d->dest, sizeof(maddr)); 425 mod_timer(&d->timer, jiffies + d->timer_intv); 426 skb = skb_clone(d->skb, GFP_ATOMIC); 427 spin_unlock_bh(&d->lock); 428 if (skb) 429 tipc_bearer_xmit_skb(net, b->identity, skb, &maddr); 430 } 431