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 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 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                 msg_set_media_addr(msg, &b_ptr->addr);
  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 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         msg_get_media_addr(msg, &media_addr);
 134         buf_discard(buf);
 135
 136         /* Validate discovery message from requesting node */
 137         if (net_id != tipc_net_id)
 138                 return;
 139         if (!tipc_addr_domain_valid(dest))
 140                 return;
 141         if (!tipc_addr_node_valid(orig))
 142                 return;
 143         if (orig == tipc_own_addr) {
 144                 if (memcmp(&media_addr, &b_ptr->addr, sizeof(media_addr)))
 145                         disc_dupl_alert(b_ptr, tipc_own_addr, &media_addr);
 146                 return;
 147         }
 148         if (!tipc_in_scope(dest, tipc_own_addr))
 149                 return;
 150         if (!tipc_in_scope(b_ptr->link_req->domain, orig))
 151                 return;
 152
 153         /* Locate structure corresponding to requesting node */
 154         n_ptr = tipc_node_find(orig);
 155         if (!n_ptr) {
 156                 n_ptr = tipc_node_create(orig);
 157                 if (!n_ptr)
 158                         return;
 159         }
 160         tipc_node_lock(n_ptr);
 161
 162         link = n_ptr->links[b_ptr->identity];
 163
 164         /* Create a link endpoint for this bearer, if necessary */
 165         if (!link) {
 166                 link = tipc_link_create(n_ptr, b_ptr, &media_addr);
 167                 if (!link) {
 168                         tipc_node_unlock(n_ptr);
 169                         return;
 170                 }
 171         }
 172
 173         /*
 174          * Ensure requesting node's media address is correct
 175          *
 176          * If media address doesn't match and the link is working, reject the
 177          * request (must be from a duplicate node).
 178          *
 179          * If media address doesn't match and the link is not working, accept
 180          * the new media address and reset the link to ensure it starts up
 181          * cleanly.
 182          */
 183         addr = &link->media_addr;
 184         if (memcmp(addr, &media_addr, sizeof(*addr))) {
 185                 if (tipc_link_is_up(link) || (!link->started)) {
 186                         disc_dupl_alert(b_ptr, orig, &media_addr);
 187                         tipc_node_unlock(n_ptr);
 188                         return;
 189                 }
 190                 warn("Resetting link <%s>, peer interface address changed\n",
 191                      link->name);
 192                 memcpy(addr, &media_addr, sizeof(*addr));
 193                 tipc_link_reset(link);
 194         }
 195
 196         /* Accept discovery message & send response, if necessary */
 197         link_fully_up = link_working_working(link);
 198
 199         if ((type == DSC_REQ_MSG) && !link_fully_up && !b_ptr->blocked) {
 200                 rbuf = tipc_disc_init_msg(DSC_RESP_MSG, orig, b_ptr);
 201                 if (rbuf) {
 202                         b_ptr->media->send_msg(rbuf, b_ptr, &media_addr);
 203                         buf_discard(rbuf);
 204                 }
 205         }
 206
 207         tipc_node_unlock(n_ptr);
 208 }
 209
 210 /**
 211  * disc_update - update frequency of periodic link setup requests
 212  * @req: ptr to link request structure
 213  *
 214  * Reinitiates discovery process if discovery object has no associated nodes
 215  * and is either not currently searching or is searching at a slow rate
 216  */
 217
 218 static void disc_update(struct link_req *req)
 219 {
 220         if (!req->num_nodes) {
 221                 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) ||
 222                     (req->timer_intv > TIPC_LINK_REQ_FAST)) {
 223                         req->timer_intv = TIPC_LINK_REQ_INIT;
 224                         k_start_timer(&req->timer, req->timer_intv);
 225                 }
 226         }
 227 }
 228
 229 /**
 230  * tipc_disc_add_dest - increment set of discovered nodes
 231  * @req: ptr to link request structure
 232  */
 233
 234 void tipc_disc_add_dest(struct link_req *req)
 235 {
 236         req->num_nodes++;
 237 }
 238
 239 /**
 240  * tipc_disc_remove_dest - decrement set of discovered nodes
 241  * @req: ptr to link request structure
 242  */
 243
 244 void tipc_disc_remove_dest(struct link_req *req)
 245 {
 246         req->num_nodes--;
 247         disc_update(req);
 248 }
 249
 250 /**
 251  * disc_send_msg - send link setup request message
 252  * @req: ptr to link request structure
 253  */
 254
 255 static void disc_send_msg(struct link_req *req)
 256 {
 257         if (!req->bearer->blocked)
 258                 tipc_bearer_send(req->bearer, req->buf, &req->dest);
 259 }
 260
 261 /**
 262  * disc_timeout - send a periodic link setup request
 263  * @req: ptr to link request structure
 264  *
 265  * Called whenever a link setup request timer associated with a bearer expires.
 266  */
 267
 268 static void disc_timeout(struct link_req *req)
 269 {
 270         int max_delay;
 271
 272         spin_lock_bh(&req->bearer->lock);
 273
 274         /* Stop searching if only desired node has been found */
 275
 276         if (tipc_node(req->domain) && req->num_nodes) {
 277                 req->timer_intv = TIPC_LINK_REQ_INACTIVE;
 278                 goto exit;
 279         }
 280
 281         /*
 282          * Send discovery message, then update discovery timer
 283          *
 284          * Keep doubling time between requests until limit is reached;
 285          * hold at fast polling rate if don't have any associated nodes,
 286          * otherwise hold at slow polling rate
 287          */
 288
 289         disc_send_msg(req);
 290
 291         req->timer_intv *= 2;
 292         if (req->num_nodes)
 293                 max_delay = TIPC_LINK_REQ_SLOW;
 294         else
 295                 max_delay = TIPC_LINK_REQ_FAST;
 296         if (req->timer_intv > max_delay)
 297                 req->timer_intv = max_delay;
 298
 299         k_start_timer(&req->timer, req->timer_intv);
 300 exit:
 301         spin_unlock_bh(&req->bearer->lock);
 302 }
 303
 304 /**
 305  * tipc_disc_create - create object to send periodic link setup requests
 306  * @b_ptr: ptr to bearer issuing requests
 307  * @dest: destination address for request messages
 308  * @dest_domain: network domain to which links can be established
 309  *
 310  * Returns 0 if successful, otherwise -errno.
 311  */
 312
 313 int tipc_disc_create(struct tipc_bearer *b_ptr,
 314                      struct tipc_media_addr *dest, u32 dest_domain)
 315 {
 316         struct link_req *req;
 317
 318         req = kmalloc(sizeof(*req), GFP_ATOMIC);
 319         if (!req)
 320                 return -ENOMEM;
 321
 322         req->buf = tipc_disc_init_msg(DSC_REQ_MSG, dest_domain, b_ptr);
 323         if (!req->buf) {
 324                 kfree(req);
 325                 return -ENOMSG;
 326         }
 327
 328         memcpy(&req->dest, dest, sizeof(*dest));
 329         req->bearer = b_ptr;
 330         req->domain = dest_domain;
 331         req->num_nodes = 0;
 332         req->timer_intv = TIPC_LINK_REQ_INIT;
 333         k_init_timer(&req->timer, (Handler)disc_timeout, (unsigned long)req);
 334         k_start_timer(&req->timer, req->timer_intv);
 335         b_ptr->link_req = req;
 336         disc_send_msg(req);
 337         return 0;
 338 }
 339
 340 /**
 341  * tipc_disc_delete - destroy object sending periodic link setup requests
 342  * @req: ptr to link request structure
 343  */
 344
 345 void tipc_disc_delete(struct link_req *req)
 346 {
 347         k_cancel_timer(&req->timer);
 348         k_term_timer(&req->timer);
 349         buf_discard(req->buf);
 350         kfree(req);
 351 }
 352