root/net/tipc/discover.c

DEFINITIONS

1. tipc_disc_init_msg
2. tipc_disc_msg_xmit
3. disc_dupl_alert
4. tipc_disc_addr_trial_msg
5. tipc_disc_rcv
6. tipc_disc_add_dest
7. tipc_disc_remove_dest
8. tipc_disc_timeout
9. tipc_disc_create
10. tipc_disc_delete
11. tipc_disc_reset

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