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![Jon Maloy](/assets/img/avatar_default.png)
The duplicate address discovery protocol is not safe against two
discoverers running in parallel. The one executing first after the
trial period is over will set the node address and change its own
message type to DSC_REQ_MSG. The one executing last may find that the
node address is already set, and never change message type, with the
result that its links may never be established.
In this commmit we ensure that the message type always is set correctly
after the trial period is over.
Fixes: 25b0b9c4e8
("tipc: handle collisions of 32-bit node address hash values")
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
414 lines
12 KiB
C
414 lines
12 KiB
C
/*
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* net/tipc/discover.c
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*
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* Copyright (c) 2003-2006, 2014-2018, Ericsson AB
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* Copyright (c) 2005-2006, 2010-2011, Wind River Systems
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the names of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "core.h"
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#include "node.h"
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#include "discover.h"
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/* min delay during bearer start up */
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#define TIPC_DISC_INIT msecs_to_jiffies(125)
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/* max delay if bearer has no links */
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#define TIPC_DISC_FAST msecs_to_jiffies(1000)
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/* max delay if bearer has links */
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#define TIPC_DISC_SLOW msecs_to_jiffies(60000)
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/* indicates no timer in use */
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#define TIPC_DISC_INACTIVE 0xffffffff
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/**
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* struct tipc_discoverer - information about an ongoing link setup request
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* @bearer_id: identity of bearer issuing requests
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* @net: network namespace instance
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* @dest: destination address for request messages
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* @domain: network domain to which links can be established
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* @num_nodes: number of nodes currently discovered (i.e. with an active link)
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* @lock: spinlock for controlling access to requests
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* @skb: request message to be (repeatedly) sent
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* @timer: timer governing period between requests
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* @timer_intv: current interval between requests (in ms)
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*/
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struct tipc_discoverer {
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u32 bearer_id;
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struct tipc_media_addr dest;
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struct net *net;
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u32 domain;
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int num_nodes;
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spinlock_t lock;
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struct sk_buff *skb;
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struct timer_list timer;
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unsigned long timer_intv;
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};
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/**
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* tipc_disc_init_msg - initialize a link setup message
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* @net: the applicable net namespace
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* @type: message type (request or response)
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* @b: ptr to bearer issuing message
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*/
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static void tipc_disc_init_msg(struct net *net, struct sk_buff *skb,
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u32 mtyp, struct tipc_bearer *b)
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{
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struct tipc_net *tn = tipc_net(net);
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u32 dest_domain = b->domain;
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struct tipc_msg *hdr;
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hdr = buf_msg(skb);
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tipc_msg_init(tn->trial_addr, hdr, LINK_CONFIG, mtyp,
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MAX_H_SIZE, dest_domain);
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msg_set_size(hdr, MAX_H_SIZE + NODE_ID_LEN);
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msg_set_non_seq(hdr, 1);
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msg_set_node_sig(hdr, tn->random);
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msg_set_node_capabilities(hdr, TIPC_NODE_CAPABILITIES);
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msg_set_dest_domain(hdr, dest_domain);
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msg_set_bc_netid(hdr, tn->net_id);
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b->media->addr2msg(msg_media_addr(hdr), &b->addr);
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msg_set_node_id(hdr, tipc_own_id(net));
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}
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static void tipc_disc_msg_xmit(struct net *net, u32 mtyp, u32 dst,
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u32 src, u32 sugg_addr,
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struct tipc_media_addr *maddr,
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struct tipc_bearer *b)
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{
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struct tipc_msg *hdr;
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struct sk_buff *skb;
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skb = tipc_buf_acquire(MAX_H_SIZE + NODE_ID_LEN, GFP_ATOMIC);
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if (!skb)
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return;
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hdr = buf_msg(skb);
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tipc_disc_init_msg(net, skb, mtyp, b);
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msg_set_sugg_node_addr(hdr, sugg_addr);
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msg_set_dest_domain(hdr, dst);
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tipc_bearer_xmit_skb(net, b->identity, skb, maddr);
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}
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/**
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* disc_dupl_alert - issue node address duplication alert
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* @b: pointer to bearer detecting duplication
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* @node_addr: duplicated node address
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* @media_addr: media address advertised by duplicated node
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*/
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static void disc_dupl_alert(struct tipc_bearer *b, u32 node_addr,
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struct tipc_media_addr *media_addr)
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{
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char media_addr_str[64];
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tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str),
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media_addr);
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pr_warn("Duplicate %x using %s seen on <%s>\n", node_addr,
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media_addr_str, b->name);
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}
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/* tipc_disc_addr_trial(): - handle an address uniqueness trial from peer
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* Returns true if message should be dropped by caller, i.e., if it is a
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* trial message or we are inside trial period. Otherwise false.
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*/
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static bool tipc_disc_addr_trial_msg(struct tipc_discoverer *d,
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struct tipc_media_addr *maddr,
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struct tipc_bearer *b,
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u32 dst, u32 src,
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u32 sugg_addr,
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u8 *peer_id,
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int mtyp)
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{
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struct net *net = d->net;
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struct tipc_net *tn = tipc_net(net);
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bool trial = time_before(jiffies, tn->addr_trial_end);
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u32 self = tipc_own_addr(net);
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if (mtyp == DSC_TRIAL_FAIL_MSG) {
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if (!trial)
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return true;
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/* Ignore if somebody else already gave new suggestion */
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if (dst != tn->trial_addr)
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return true;
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/* Otherwise update trial address and restart trial period */
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tn->trial_addr = sugg_addr;
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msg_set_prevnode(buf_msg(d->skb), sugg_addr);
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tn->addr_trial_end = jiffies + msecs_to_jiffies(1000);
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return true;
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}
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/* Apply trial address if we just left trial period */
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if (!trial && !self) {
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tipc_net_finalize(net, tn->trial_addr);
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msg_set_type(buf_msg(d->skb), DSC_REQ_MSG);
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}
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/* Accept regular link requests/responses only after trial period */
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if (mtyp != DSC_TRIAL_MSG)
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return trial;
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sugg_addr = tipc_node_try_addr(net, peer_id, src);
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if (sugg_addr)
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tipc_disc_msg_xmit(net, DSC_TRIAL_FAIL_MSG, src,
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self, sugg_addr, maddr, b);
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return true;
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}
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/**
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* tipc_disc_rcv - handle incoming discovery message (request or response)
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* @net: applicable net namespace
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* @skb: buffer containing message
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* @b: bearer that message arrived on
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*/
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void tipc_disc_rcv(struct net *net, struct sk_buff *skb,
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struct tipc_bearer *b)
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{
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struct tipc_net *tn = tipc_net(net);
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struct tipc_msg *hdr = buf_msg(skb);
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u16 caps = msg_node_capabilities(hdr);
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bool legacy = tn->legacy_addr_format;
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u32 sugg = msg_sugg_node_addr(hdr);
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u32 signature = msg_node_sig(hdr);
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u8 peer_id[NODE_ID_LEN] = {0,};
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u32 dst = msg_dest_domain(hdr);
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u32 net_id = msg_bc_netid(hdr);
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struct tipc_media_addr maddr;
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u32 src = msg_prevnode(hdr);
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u32 mtyp = msg_type(hdr);
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bool dupl_addr = false;
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bool respond = false;
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u32 self;
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int err;
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skb_linearize(skb);
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hdr = buf_msg(skb);
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if (caps & TIPC_NODE_ID128)
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memcpy(peer_id, msg_node_id(hdr), NODE_ID_LEN);
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else
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sprintf(peer_id, "%x", src);
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err = b->media->msg2addr(b, &maddr, msg_media_addr(hdr));
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kfree_skb(skb);
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if (err || maddr.broadcast) {
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pr_warn_ratelimited("Rcv corrupt discovery message\n");
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return;
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}
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/* Ignore discovery messages from own node */
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if (!memcmp(&maddr, &b->addr, sizeof(maddr)))
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return;
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if (net_id != tn->net_id)
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return;
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if (tipc_disc_addr_trial_msg(b->disc, &maddr, b, dst,
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src, sugg, peer_id, mtyp))
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return;
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self = tipc_own_addr(net);
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/* Message from somebody using this node's address */
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if (in_own_node(net, src)) {
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disc_dupl_alert(b, self, &maddr);
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return;
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}
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if (!tipc_in_scope(legacy, dst, self))
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return;
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if (!tipc_in_scope(legacy, b->domain, src))
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return;
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tipc_node_check_dest(net, src, peer_id, b, caps, signature,
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&maddr, &respond, &dupl_addr);
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if (dupl_addr)
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disc_dupl_alert(b, src, &maddr);
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if (!respond)
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return;
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if (mtyp != DSC_REQ_MSG)
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return;
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tipc_disc_msg_xmit(net, DSC_RESP_MSG, src, self, 0, &maddr, b);
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}
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/* tipc_disc_add_dest - increment set of discovered nodes
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*/
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void tipc_disc_add_dest(struct tipc_discoverer *d)
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{
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spin_lock_bh(&d->lock);
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d->num_nodes++;
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spin_unlock_bh(&d->lock);
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}
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/* tipc_disc_remove_dest - decrement set of discovered nodes
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*/
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void tipc_disc_remove_dest(struct tipc_discoverer *d)
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{
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int intv, num;
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spin_lock_bh(&d->lock);
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d->num_nodes--;
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num = d->num_nodes;
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intv = d->timer_intv;
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if (!num && (intv == TIPC_DISC_INACTIVE || intv > TIPC_DISC_FAST)) {
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d->timer_intv = TIPC_DISC_INIT;
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mod_timer(&d->timer, jiffies + d->timer_intv);
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}
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spin_unlock_bh(&d->lock);
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}
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/* tipc_disc_timeout - send a periodic link setup request
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* Called whenever a link setup request timer associated with a bearer expires.
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* - Keep doubling time between sent request until limit is reached;
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* - Hold at fast polling rate if we don't have any associated nodes
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* - Otherwise hold at slow polling rate
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*/
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static void tipc_disc_timeout(struct timer_list *t)
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{
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struct tipc_discoverer *d = from_timer(d, t, timer);
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struct tipc_net *tn = tipc_net(d->net);
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struct tipc_media_addr maddr;
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struct sk_buff *skb = NULL;
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struct net *net = d->net;
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u32 bearer_id;
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spin_lock_bh(&d->lock);
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/* Stop searching if only desired node has been found */
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if (tipc_node(d->domain) && d->num_nodes) {
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d->timer_intv = TIPC_DISC_INACTIVE;
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goto exit;
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}
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/* Trial period over ? */
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if (!time_before(jiffies, tn->addr_trial_end)) {
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/* Did we just leave it ? */
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if (!tipc_own_addr(net))
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tipc_net_finalize(net, tn->trial_addr);
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msg_set_type(buf_msg(d->skb), DSC_REQ_MSG);
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msg_set_prevnode(buf_msg(d->skb), tipc_own_addr(net));
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}
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/* Adjust timeout interval according to discovery phase */
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if (time_before(jiffies, tn->addr_trial_end)) {
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d->timer_intv = TIPC_DISC_INIT;
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} else {
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d->timer_intv *= 2;
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if (d->num_nodes && d->timer_intv > TIPC_DISC_SLOW)
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d->timer_intv = TIPC_DISC_SLOW;
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else if (!d->num_nodes && d->timer_intv > TIPC_DISC_FAST)
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d->timer_intv = TIPC_DISC_FAST;
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}
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mod_timer(&d->timer, jiffies + d->timer_intv);
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memcpy(&maddr, &d->dest, sizeof(maddr));
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skb = skb_clone(d->skb, GFP_ATOMIC);
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bearer_id = d->bearer_id;
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exit:
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spin_unlock_bh(&d->lock);
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if (skb)
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tipc_bearer_xmit_skb(net, bearer_id, skb, &maddr);
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}
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/**
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* tipc_disc_create - create object to send periodic link setup requests
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* @net: the applicable net namespace
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* @b: ptr to bearer issuing requests
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* @dest: destination address for request messages
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* @dest_domain: network domain to which links can be established
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*
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* Returns 0 if successful, otherwise -errno.
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*/
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int tipc_disc_create(struct net *net, struct tipc_bearer *b,
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struct tipc_media_addr *dest, struct sk_buff **skb)
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{
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struct tipc_net *tn = tipc_net(net);
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struct tipc_discoverer *d;
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d = kmalloc(sizeof(*d), GFP_ATOMIC);
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if (!d)
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return -ENOMEM;
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d->skb = tipc_buf_acquire(MAX_H_SIZE + NODE_ID_LEN, GFP_ATOMIC);
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if (!d->skb) {
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kfree(d);
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return -ENOMEM;
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}
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tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
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/* Do we need an address trial period first ? */
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if (!tipc_own_addr(net)) {
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tn->addr_trial_end = jiffies + msecs_to_jiffies(1000);
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msg_set_type(buf_msg(d->skb), DSC_TRIAL_MSG);
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}
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memcpy(&d->dest, dest, sizeof(*dest));
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d->net = net;
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d->bearer_id = b->identity;
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d->domain = b->domain;
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d->num_nodes = 0;
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d->timer_intv = TIPC_DISC_INIT;
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spin_lock_init(&d->lock);
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timer_setup(&d->timer, tipc_disc_timeout, 0);
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mod_timer(&d->timer, jiffies + d->timer_intv);
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b->disc = d;
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*skb = skb_clone(d->skb, GFP_ATOMIC);
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return 0;
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}
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/**
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* tipc_disc_delete - destroy object sending periodic link setup requests
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* @d: ptr to link duest structure
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*/
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void tipc_disc_delete(struct tipc_discoverer *d)
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{
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del_timer_sync(&d->timer);
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kfree_skb(d->skb);
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kfree(d);
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}
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/**
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* tipc_disc_reset - reset object to send periodic link setup requests
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* @net: the applicable net namespace
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* @b: ptr to bearer issuing requests
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* @dest_domain: network domain to which links can be established
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*/
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void tipc_disc_reset(struct net *net, struct tipc_bearer *b)
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{
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struct tipc_discoverer *d = b->disc;
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struct tipc_media_addr maddr;
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struct sk_buff *skb;
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spin_lock_bh(&d->lock);
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tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
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d->net = net;
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d->bearer_id = b->identity;
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d->domain = b->domain;
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d->num_nodes = 0;
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d->timer_intv = TIPC_DISC_INIT;
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memcpy(&maddr, &d->dest, sizeof(maddr));
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mod_timer(&d->timer, jiffies + d->timer_intv);
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skb = skb_clone(d->skb, GFP_ATOMIC);
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spin_unlock_bh(&d->lock);
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if (skb)
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tipc_bearer_xmit_skb(net, b->identity, skb, &maddr);
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}
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