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TOMOYO Linux Cross Reference
Linux/net/tipc/discover.c

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  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);
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(unsigned long data)
228 {
229         struct tipc_link_req *req = (struct tipc_link_req *)data;
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);
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         setup_timer(&req->timer, disc_timeout, (unsigned long)req);
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 }
337 

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