net/tipc/discover.c

   1 /*
   2  * net/tipc/discover.c
   3  *
   4  * Copyright (c) 2003-2006, 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 "link.h"
  39 #include "discover.h"
  40
  41 #define TIPC_LINK_REQ_INIT      125     /* min delay during bearer start up */
  42 #define TIPC_LINK_REQ_FAST      1000    /* max delay if bearer has no links */
  43 #define TIPC_LINK_REQ_SLOW      60000   /* max delay if bearer has links */
  44 #define TIPC_LINK_REQ_INACTIVE  0xffffffff /* indicates no timer in use */
  45
  46
  47 /**
  48  * struct tipc_link_req - information about an ongoing link setup request
  49  * @bearer: bearer issuing requests
  50  * @dest: destination address for request messages
  51  * @domain: network domain to which links can be established
  52  * @num_nodes: number of nodes currently discovered (i.e. with an active link)
  53  * @buf: request message to be (repeatedly) sent
  54  * @timer: timer governing period between requests
  55  * @timer_intv: current interval between requests (in ms)
  56  */
  57 struct tipc_link_req {
  58         struct tipc_bearer *bearer;
  59         struct tipc_media_addr dest;
  60         u32 domain;
  61         int num_nodes;
  62         struct sk_buff *buf;
  63         struct timer_list timer;
  64         unsigned int timer_intv;
  65 };
  66
  67 /**
  68  * tipc_disc_init_msg - initialize a link setup message
  69  * @type: message type (request or response)
  70  * @dest_domain: network domain of node(s) which should respond to message
  71  * @b_ptr: ptr to bearer issuing message
  72  */
  73
  74 static struct sk_buff *tipc_disc_init_msg(u32 type,
  75                                           u32 dest_domain,
  76                                           struct tipc_bearer *b_ptr)
  77 {
  78         struct sk_buff *buf = tipc_buf_acquire(INT_H_SIZE);
  79         struct tipc_msg *msg;
  80
  81         if (buf) {
  82                 msg = buf_msg(buf);
  83                 tipc_msg_init(msg, LINK_CONFIG, type, INT_H_SIZE, dest_domain);
  84                 msg_set_non_seq(msg, 1);
  85                 msg_set_dest_domain(msg, dest_domain);
  86                 msg_set_bc_netid(msg, tipc_net_id);
  87                 b_ptr->media->addr2msg(&b_ptr->addr, msg_media_addr(msg));
  88         }
  89         return buf;
  90 }
  91
  92 /**
  93  * disc_dupl_alert - issue node address duplication alert
  94  * @b_ptr: pointer to bearer detecting duplication
  95  * @node_addr: duplicated node address
  96  * @media_addr: media address advertised by duplicated node
  97  */
  98
  99 static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr,
 100                             struct tipc_media_addr *media_addr)
 101 {
 102         char node_addr_str[16];
 103         char media_addr_str[64];
 104         struct print_buf pb;
 105
 106         tipc_addr_string_fill(node_addr_str, node_addr);
 107         tipc_printbuf_init(&pb, media_addr_str, sizeof(media_addr_str));
 108         tipc_media_addr_printf(&pb, media_addr);
 109         tipc_printbuf_validate(&pb);
 110         warn("Duplicate %s using %s seen on <%s>\n",
 111              node_addr_str, media_addr_str, b_ptr->name);
 112 }
 113
 114 /**
 115  * tipc_disc_recv_msg - handle incoming link setup message (request or response)
 116  * @buf: buffer containing message
 117  * @b_ptr: bearer that message arrived on
 118  */
 119
 120 void tipc_disc_recv_msg(struct sk_buff *buf, struct tipc_bearer *b_ptr)
 121 {
 122         struct tipc_node *n_ptr;
 123         struct tipc_link *link;
 124         struct tipc_media_addr media_addr, *addr;
 125         struct sk_buff *rbuf;
 126         struct tipc_msg *msg = buf_msg(buf);
 127         u32 dest = msg_dest_domain(msg);
 128         u32 orig = msg_prevnode(msg);
 129         u32 net_id = msg_bc_netid(msg);
 130         u32 type = msg_type(msg);
 131         int link_fully_up;
 132
 133         media_addr.broadcast = 1;
 134         b_ptr->media->msg2addr(&media_addr, msg_media_addr(msg));
 135         buf_discard(buf);
 136
 137         /* Validate discovery message from requesting node */
 138         if (net_id != tipc_net_id)
 139                 return;
 140         if (media_addr.broadcast)
 141                 return;
 142         if (!tipc_addr_domain_valid(dest))
 143                 return;
 144         if (!tipc_addr_node_valid(orig))
 145                 return;
 146         if (orig == tipc_own_addr) {
 147                 if (memcmp(&media_addr, &b_ptr->addr, sizeof(media_addr)))
 148                         disc_dupl_alert(b_ptr, tipc_own_addr, &media_addr);
 149                 return;
 150         }
 151         if (!tipc_in_scope(dest, tipc_own_addr))
 152                 return;
 153         if (!tipc_in_scope(b_ptr->link_req->domain, orig))
 154                 return;
 155
 156         /* Locate structure corresponding to requesting node */
 157         n_ptr = tipc_node_find(orig);
 158         if (!n_ptr) {
 159                 n_ptr = tipc_node_create(orig);
 160                 if (!n_ptr)
 161                         return;
 162         }
 163         tipc_node_lock(n_ptr);
 164
 165         link = n_ptr->links[b_ptr->identity];
 166
 167         /* Create a link endpoint for this bearer, if necessary */
 168         if (!link) {
 169                 link = tipc_link_create(n_ptr, b_ptr, &media_addr);
 170                 if (!link) {
 171                         tipc_node_unlock(n_ptr);
 172                         return;
 173                 }
 174         }
 175
 176         /*
 177          * Ensure requesting node's media address is correct
 178          *
 179          * If media address doesn't match and the link is working, reject the
 180          * request (must be from a duplicate node).
 181          *
 182          * If media address doesn't match and the link is not working, accept
 183          * the new media address and reset the link to ensure it starts up
 184          * cleanly.
 185          */
 186         addr = &link->media_addr;
 187         if (memcmp(addr, &media_addr, sizeof(*addr))) {
 188                 if (tipc_link_is_up(link) || (!link->started)) {
 189                         disc_dupl_alert(b_ptr, orig, &media_addr);
 190                         tipc_node_unlock(n_ptr);
 191                         return;
 192                 }
 193                 warn("Resetting link <%s>, peer interface address changed\n",
 194                      link->name);
 195                 memcpy(addr, &media_addr, sizeof(*addr));
 196                 tipc_link_reset(link);
 197         }
 198
 199         /* Accept discovery message & send response, if necessary */
 200         link_fully_up = link_working_working(link);
 201
 202         if ((type == DSC_REQ_MSG) && !link_fully_up && !b_ptr->blocked) {
 203                 rbuf = tipc_disc_init_msg(DSC_RESP_MSG, orig, b_ptr);
 204                 if (rbuf) {
 205                         b_ptr->media->send_msg(rbuf, b_ptr, &media_addr);
 206                         buf_discard(rbuf);
 207                 }
 208         }
 209
 210         tipc_node_unlock(n_ptr);
 211 }
 212
 213 /**
 214  * disc_update - update frequency of periodic link setup requests
 215  * @req: ptr to link request structure
 216  *
 217  * Reinitiates discovery process if discovery object has no associated nodes
 218  * and is either not currently searching or is searching at a slow rate
 219  */
 220
 221 static void disc_update(struct tipc_link_req *req)
 222 {
 223         if (!req->num_nodes) {
 224                 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) ||
 225                     (req->timer_intv > TIPC_LINK_REQ_FAST)) {
 226                         req->timer_intv = TIPC_LINK_REQ_INIT;
 227                         k_start_timer(&req->timer, req->timer_intv);
 228                 }
 229         }
 230 }
 231
 232 /**
 233  * tipc_disc_add_dest - increment set of discovered nodes
 234  * @req: ptr to link request structure
 235  */
 236
 237 void tipc_disc_add_dest(struct tipc_link_req *req)
 238 {
 239         req->num_nodes++;
 240 }
 241
 242 /**
 243  * tipc_disc_remove_dest - decrement set of discovered nodes
 244  * @req: ptr to link request structure
 245  */
 246
 247 void tipc_disc_remove_dest(struct tipc_link_req *req)
 248 {
 249         req->num_nodes--;
 250         disc_update(req);
 251 }
 252
 253 /**
 254  * disc_send_msg - send link setup request message
 255  * @req: ptr to link request structure
 256  */
 257
 258 static void disc_send_msg(struct tipc_link_req *req)
 259 {
 260         if (!req->bearer->blocked)
 261                 tipc_bearer_send(req->bearer, req->buf, &req->dest);
 262 }
 263
 264 /**
 265  * disc_timeout - send a periodic link setup request
 266  * @req: ptr to link request structure
 267  *
 268  * Called whenever a link setup request timer associated with a bearer expires.
 269  */
 270
 271 static void disc_timeout(struct tipc_link_req *req)
 272 {
 273         int max_delay;
 274
 275         spin_lock_bh(&req->bearer->lock);
 276
 277         /* Stop searching if only desired node has been found */
 278
 279         if (tipc_node(req->domain) && req->num_nodes) {
 280                 req->timer_intv = TIPC_LINK_REQ_INACTIVE;
 281                 goto exit;
 282         }
 283
 284         /*
 285          * Send discovery message, then update discovery timer
 286          *
 287          * Keep doubling time between requests until limit is reached;
 288          * hold at fast polling rate if don't have any associated nodes,
 289          * otherwise hold at slow polling rate
 290          */
 291
 292         disc_send_msg(req);
 293
 294         req->timer_intv *= 2;
 295         if (req->num_nodes)
 296                 max_delay = TIPC_LINK_REQ_SLOW;
 297         else
 298                 max_delay = TIPC_LINK_REQ_FAST;
 299         if (req->timer_intv > max_delay)
 300                 req->timer_intv = max_delay;
 301
 302         k_start_timer(&req->timer, req->timer_intv);
 303 exit:
 304         spin_unlock_bh(&req->bearer->lock);
 305 }
 306
 307 /**
 308  * tipc_disc_create - create object to send periodic link setup requests
 309  * @b_ptr: ptr to bearer issuing requests
 310  * @dest: destination address for request messages
 311  * @dest_domain: network domain to which links can be established
 312  *
 313  * Returns 0 if successful, otherwise -errno.
 314  */
 315
 316 int tipc_disc_create(struct tipc_bearer *b_ptr,
 317                      struct tipc_media_addr *dest, u32 dest_domain)
 318 {
 319         struct tipc_link_req *req;
 320
 321         req = kmalloc(sizeof(*req), GFP_ATOMIC);
 322         if (!req)
 323                 return -ENOMEM;
 324
 325         req->buf = tipc_disc_init_msg(DSC_REQ_MSG, dest_domain, b_ptr);
 326         if (!req->buf) {
 327                 kfree(req);
 328                 return -ENOMSG;
 329         }
 330
 331         memcpy(&req->dest, dest, sizeof(*dest));
 332         req->bearer = b_ptr;
 333         req->domain = dest_domain;
 334         req->num_nodes = 0;
 335         req->timer_intv = TIPC_LINK_REQ_INIT;
 336         k_init_timer(&req->timer, (Handler)disc_timeout, (unsigned long)req);
 337         k_start_timer(&req->timer, req->timer_intv);
 338         b_ptr->link_req = req;
 339         disc_send_msg(req);
 340         return 0;
 341 }
 342
 343 /**
 344  * tipc_disc_delete - destroy object sending periodic link setup requests
 345  * @req: ptr to link request structure
 346  */
 347
 348 void tipc_disc_delete(struct tipc_link_req *req)
 349 {
 350         k_cancel_timer(&req->timer);
 351         k_term_timer(&req->timer);
 352         buf_discard(req->buf);
 353         kfree(req);
 354 }
 355