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