linux/net/tipc/discover.c
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   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 */
  62struct 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 */
  81static 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
 102static 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 */
 126static 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 */
 141static 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 */
 193void 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 */
 260void 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 */
 269void 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 */
 290static 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;
 332exit:
 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 */
 347int 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 */
 386void 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 */
 398void 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}
 418