net/tipc/discover.c

   1 /*
   2  * net/tipc/discover.c
   3  *
   4  * Copyright (c) 2003-2006, 2014-2015, 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_LINK_REQ_INIT      msecs_to_jiffies(125)
  43 /* max delay if bearer has no links */
  44 #define TIPC_LINK_REQ_FAST      msecs_to_jiffies(1000)
  45 /* max delay if bearer has links */
  46 #define TIPC_LINK_REQ_SLOW      msecs_to_jiffies(60000)
  47 /* indicates no timer in use */
  48 #define TIPC_LINK_REQ_INACTIVE  0xffffffff
  49
  50 /**
  51  * struct tipc_link_req - 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  * @buf: 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_link_req {
  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 *buf;
  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 *buf, u32 type,
  81                                struct tipc_bearer *b)
  82 {
  83         struct tipc_net *tn = net_generic(net, tipc_net_id);
  84         struct tipc_msg *msg;
  85         u32 dest_domain = b->domain;
  86
  87         msg = buf_msg(buf);
  88         tipc_msg_init(tn->own_addr, msg, LINK_CONFIG, type,
  89                       MAX_H_SIZE, dest_domain);
  90         msg_set_non_seq(msg, 1);
  91         msg_set_node_sig(msg, tn->random);
  92         msg_set_node_capabilities(msg, TIPC_NODE_CAPABILITIES);
  93         msg_set_dest_domain(msg, dest_domain);
  94         msg_set_bc_netid(msg, tn->net_id);
  95         b->media->addr2msg(msg_media_addr(msg), &b->addr);
  96 }
  97
  98 /**
  99  * disc_dupl_alert - issue node address duplication alert
 100  * @b: pointer to bearer detecting duplication
 101  * @node_addr: duplicated node address
 102  * @media_addr: media address advertised by duplicated node
 103  */
 104 static void disc_dupl_alert(struct tipc_bearer *b, u32 node_addr,
 105                             struct tipc_media_addr *media_addr)
 106 {
 107         char node_addr_str[16];
 108         char media_addr_str[64];
 109
 110         tipc_addr_string_fill(node_addr_str, node_addr);
 111         tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str),
 112                                media_addr);
 113         pr_warn("Duplicate %s using %s seen on <%s>\n", node_addr_str,
 114                 media_addr_str, b->name);
 115 }
 116
 117 /**
 118  * tipc_disc_rcv - handle incoming discovery message (request or response)
 119  * @net: the applicable net namespace
 120  * @buf: buffer containing message
 121  * @bearer: bearer that message arrived on
 122  */
 123 void tipc_disc_rcv(struct net *net, struct sk_buff *skb,
 124                    struct tipc_bearer *bearer)
 125 {
 126         struct tipc_net *tn = net_generic(net, tipc_net_id);
 127         struct tipc_media_addr maddr;
 128         struct sk_buff *rskb;
 129         struct tipc_msg *hdr = buf_msg(skb);
 130         u32 ddom = msg_dest_domain(hdr);
 131         u32 onode = msg_prevnode(hdr);
 132         u32 net_id = msg_bc_netid(hdr);
 133         u32 mtyp = msg_type(hdr);
 134         u32 signature = msg_node_sig(hdr);
 135         u16 caps = msg_node_capabilities(hdr);
 136         bool respond = false;
 137         bool dupl_addr = false;
 138         int err;
 139
 140         err = bearer->media->msg2addr(bearer, &maddr, msg_media_addr(hdr));
 141         kfree_skb(skb);
 142         if (err)
 143                 return;
 144
 145         /* Ensure message from node is valid and communication is permitted */
 146         if (net_id != tn->net_id)
 147                 return;
 148         if (maddr.broadcast)
 149                 return;
 150         if (!tipc_addr_domain_valid(ddom))
 151                 return;
 152         if (!tipc_addr_node_valid(onode))
 153                 return;
 154
 155         if (in_own_node(net, onode)) {
 156                 if (memcmp(&maddr, &bearer->addr, sizeof(maddr)))
 157                         disc_dupl_alert(bearer, tn->own_addr, &maddr);
 158                 return;
 159         }
 160         if (!tipc_in_scope(ddom, tn->own_addr))
 161                 return;
 162         if (!tipc_in_scope(bearer->domain, onode))
 163                 return;
 164
 165         tipc_node_check_dest(net, onode, bearer, caps, signature,
 166                              &maddr, &respond, &dupl_addr);
 167         if (dupl_addr)
 168                 disc_dupl_alert(bearer, onode, &maddr);
 169
 170         /* Send response, if necessary */
 171         if (respond && (mtyp == DSC_REQ_MSG)) {
 172                 rskb = tipc_buf_acquire(MAX_H_SIZE, GFP_ATOMIC);
 173                 if (!rskb)
 174                         return;
 175                 tipc_disc_init_msg(net, rskb, DSC_RESP_MSG, bearer);
 176                 tipc_bearer_xmit_skb(net, bearer->identity, rskb, &maddr);
 177         }
 178 }
 179
 180 /**
 181  * disc_update - update frequency of periodic link setup requests
 182  * @req: ptr to link request structure
 183  *
 184  * Reinitiates discovery process if discovery object has no associated nodes
 185  * and is either not currently searching or is searching at a slow rate
 186  */
 187 static void disc_update(struct tipc_link_req *req)
 188 {
 189         if (!req->num_nodes) {
 190                 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) ||
 191                     (req->timer_intv > TIPC_LINK_REQ_FAST)) {
 192                         req->timer_intv = TIPC_LINK_REQ_INIT;
 193                         mod_timer(&req->timer, jiffies + req->timer_intv);
 194                 }
 195         }
 196 }
 197
 198 /**
 199  * tipc_disc_add_dest - increment set of discovered nodes
 200  * @req: ptr to link request structure
 201  */
 202 void tipc_disc_add_dest(struct tipc_link_req *req)
 203 {
 204         spin_lock_bh(&req->lock);
 205         req->num_nodes++;
 206         spin_unlock_bh(&req->lock);
 207 }
 208
 209 /**
 210  * tipc_disc_remove_dest - decrement set of discovered nodes
 211  * @req: ptr to link request structure
 212  */
 213 void tipc_disc_remove_dest(struct tipc_link_req *req)
 214 {
 215         spin_lock_bh(&req->lock);
 216         req->num_nodes--;
 217         disc_update(req);
 218         spin_unlock_bh(&req->lock);
 219 }
 220
 221 /**
 222  * disc_timeout - send a periodic link setup request
 223  * @data: ptr to link request structure
 224  *
 225  * Called whenever a link setup request timer associated with a bearer expires.
 226  */
 227 static void disc_timeout(struct timer_list *t)
 228 {
 229         struct tipc_link_req *req = from_timer(req, t, timer);
 230         struct sk_buff *skb;
 231         int max_delay;
 232
 233         spin_lock_bh(&req->lock);
 234
 235         /* Stop searching if only desired node has been found */
 236         if (tipc_node(req->domain) && req->num_nodes) {
 237                 req->timer_intv = TIPC_LINK_REQ_INACTIVE;
 238                 goto exit;
 239         }
 240
 241         /*
 242          * Send discovery message, then update discovery timer
 243          *
 244          * Keep doubling time between requests until limit is reached;
 245          * hold at fast polling rate if don't have any associated nodes,
 246          * otherwise hold at slow polling rate
 247          */
 248         skb = skb_clone(req->buf, GFP_ATOMIC);
 249         if (skb)
 250                 tipc_bearer_xmit_skb(req->net, req->bearer_id, skb, &req->dest);
 251         req->timer_intv *= 2;
 252         if (req->num_nodes)
 253                 max_delay = TIPC_LINK_REQ_SLOW;
 254         else
 255                 max_delay = TIPC_LINK_REQ_FAST;
 256         if (req->timer_intv > max_delay)
 257                 req->timer_intv = max_delay;
 258
 259         mod_timer(&req->timer, jiffies + req->timer_intv);
 260 exit:
 261         spin_unlock_bh(&req->lock);
 262 }
 263
 264 /**
 265  * tipc_disc_create - create object to send periodic link setup requests
 266  * @net: the applicable net namespace
 267  * @b: ptr to bearer issuing requests
 268  * @dest: destination address for request messages
 269  * @dest_domain: network domain to which links can be established
 270  *
 271  * Returns 0 if successful, otherwise -errno.
 272  */
 273 int tipc_disc_create(struct net *net, struct tipc_bearer *b,
 274                      struct tipc_media_addr *dest, struct sk_buff **skb)
 275 {
 276         struct tipc_link_req *req;
 277
 278         req = kmalloc(sizeof(*req), GFP_ATOMIC);
 279         if (!req)
 280                 return -ENOMEM;
 281         req->buf = tipc_buf_acquire(MAX_H_SIZE, GFP_ATOMIC);
 282         if (!req->buf) {
 283                 kfree(req);
 284                 return -ENOMEM;
 285         }
 286
 287         tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b);
 288         memcpy(&req->dest, dest, sizeof(*dest));
 289         req->net = net;
 290         req->bearer_id = b->identity;
 291         req->domain = b->domain;
 292         req->num_nodes = 0;
 293         req->timer_intv = TIPC_LINK_REQ_INIT;
 294         spin_lock_init(&req->lock);
 295         timer_setup(&req->timer, disc_timeout, 0);
 296         mod_timer(&req->timer, jiffies + req->timer_intv);
 297         b->link_req = req;
 298         *skb = skb_clone(req->buf, GFP_ATOMIC);
 299         return 0;
 300 }
 301
 302 /**
 303  * tipc_disc_delete - destroy object sending periodic link setup requests
 304  * @req: ptr to link request structure
 305  */
 306 void tipc_disc_delete(struct tipc_link_req *req)
 307 {
 308         del_timer_sync(&req->timer);
 309         kfree_skb(req->buf);
 310         kfree(req);
 311 }
 312
 313 /**
 314  * tipc_disc_reset - reset object to send periodic link setup requests
 315  * @net: the applicable net namespace
 316  * @b: ptr to bearer issuing requests
 317  * @dest_domain: network domain to which links can be established
 318  */
 319 void tipc_disc_reset(struct net *net, struct tipc_bearer *b)
 320 {
 321         struct tipc_link_req *req = b->link_req;
 322         struct sk_buff *skb;
 323
 324         spin_lock_bh(&req->lock);
 325         tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b);
 326         req->net = net;
 327         req->bearer_id = b->identity;
 328         req->domain = b->domain;
 329         req->num_nodes = 0;
 330         req->timer_intv = TIPC_LINK_REQ_INIT;
 331         mod_timer(&req->timer, jiffies + req->timer_intv);
 332         skb = skb_clone(req->buf, GFP_ATOMIC);
 333         if (skb)
 334                 tipc_bearer_xmit_skb(net, req->bearer_id, skb, &req->dest);
 335         spin_unlock_bh(&req->lock);
 336 }