net/tipc/discover.c

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