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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 16:26:39 +07:00
f9a2c80b8b
Currently, only 'bearer_lock' is used to protect struct link_req in the function disc_timeout(). This is unsafe, since the member fields 'num_nodes' and 'timer_intv' might be accessed by below three different threads simultaneously, none of them grabbing bearer_lock in the critical region: link_activate() tipc_bearer_add_dest() tipc_disc_add_dest() req->num_nodes++; tipc_link_reset() tipc_bearer_remove_dest() tipc_disc_remove_dest() req->num_nodes-- disc_update() read req->num_nodes write req->timer_intv disc_timeout() read req->num_nodes read/write req->timer_intv Without lock protection, the only symptom of a race is that discovery messages occasionally may not be sent out. This is not fatal, since such messages are best-effort anyway. On the other hand, since discovery messages are not time critical, adding a protecting lock brings no serious overhead either. So we add a new, dedicated spinlock in order to guarantee absolute data consistency in link_req objects. This also helps reduce the overall role of the bearer_lock, which we want to remove completely in a later commit series. Signed-off-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
384 lines
11 KiB
C
384 lines
11 KiB
C
/*
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* net/tipc/discover.c
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*
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* Copyright (c) 2003-2006, 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 "link.h"
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#include "discover.h"
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#define TIPC_LINK_REQ_INIT 125 /* min delay during bearer start up */
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#define TIPC_LINK_REQ_FAST 1000 /* max delay if bearer has no links */
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#define TIPC_LINK_REQ_SLOW 60000 /* max delay if bearer has links */
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#define TIPC_LINK_REQ_INACTIVE 0xffffffff /* indicates no timer in use */
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/**
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* struct tipc_link_req - information about an ongoing link setup request
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* @bearer: bearer issuing requests
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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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* @buf: 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_link_req {
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struct tipc_bearer *bearer;
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struct tipc_media_addr dest;
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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 *buf;
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struct timer_list timer;
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unsigned int 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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* @type: message type (request or response)
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* @dest_domain: network domain of node(s) which should respond to message
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* @b_ptr: ptr to bearer issuing message
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*/
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static struct sk_buff *tipc_disc_init_msg(u32 type, u32 dest_domain,
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struct tipc_bearer *b_ptr)
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{
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struct sk_buff *buf = tipc_buf_acquire(INT_H_SIZE);
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struct tipc_msg *msg;
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if (buf) {
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msg = buf_msg(buf);
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tipc_msg_init(msg, LINK_CONFIG, type, INT_H_SIZE, dest_domain);
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msg_set_non_seq(msg, 1);
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msg_set_node_sig(msg, tipc_random);
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msg_set_dest_domain(msg, dest_domain);
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msg_set_bc_netid(msg, tipc_net_id);
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b_ptr->media->addr2msg(&b_ptr->addr, msg_media_addr(msg));
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}
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return buf;
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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_ptr: 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_ptr, u32 node_addr,
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struct tipc_media_addr *media_addr)
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{
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char node_addr_str[16];
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char media_addr_str[64];
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tipc_addr_string_fill(node_addr_str, node_addr);
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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 %s using %s seen on <%s>\n", node_addr_str,
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media_addr_str, b_ptr->name);
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}
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/**
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* tipc_disc_recv_msg - handle incoming link setup message (request or response)
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* @buf: buffer containing message
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* @b_ptr: bearer that message arrived on
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*/
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void tipc_disc_recv_msg(struct sk_buff *buf, struct tipc_bearer *b_ptr)
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{
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struct tipc_node *n_ptr;
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struct tipc_link *link;
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struct tipc_media_addr media_addr;
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struct sk_buff *rbuf;
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struct tipc_msg *msg = buf_msg(buf);
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u32 dest = msg_dest_domain(msg);
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u32 orig = msg_prevnode(msg);
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u32 net_id = msg_bc_netid(msg);
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u32 type = msg_type(msg);
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u32 signature = msg_node_sig(msg);
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int addr_mismatch;
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int link_fully_up;
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media_addr.broadcast = 1;
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b_ptr->media->msg2addr(b_ptr, &media_addr, msg_media_addr(msg));
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kfree_skb(buf);
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/* Ensure message from node is valid and communication is permitted */
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if (net_id != tipc_net_id)
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return;
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if (media_addr.broadcast)
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return;
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if (!tipc_addr_domain_valid(dest))
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return;
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if (!tipc_addr_node_valid(orig))
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return;
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if (orig == tipc_own_addr) {
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if (memcmp(&media_addr, &b_ptr->addr, sizeof(media_addr)))
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disc_dupl_alert(b_ptr, tipc_own_addr, &media_addr);
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return;
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}
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if (!tipc_in_scope(dest, tipc_own_addr))
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return;
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if (!tipc_in_scope(b_ptr->link_req->domain, orig))
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return;
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/* Locate structure corresponding to requesting node */
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n_ptr = tipc_node_find(orig);
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if (!n_ptr) {
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n_ptr = tipc_node_create(orig);
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if (!n_ptr)
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return;
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}
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tipc_node_lock(n_ptr);
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/* Prepare to validate requesting node's signature and media address */
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link = n_ptr->links[b_ptr->identity];
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addr_mismatch = (link != NULL) &&
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memcmp(&link->media_addr, &media_addr, sizeof(media_addr));
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/*
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* Ensure discovery message's signature is correct
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*
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* If signature is incorrect and there is no working link to the node,
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* accept the new signature but invalidate all existing links to the
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* node so they won't re-activate without a new discovery message.
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*
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* If signature is incorrect and the requested link to the node is
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* working, accept the new signature. (This is an instance of delayed
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* rediscovery, where a link endpoint was able to re-establish contact
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* with its peer endpoint on a node that rebooted before receiving a
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* discovery message from that node.)
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*
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* If signature is incorrect and there is a working link to the node
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* that is not the requested link, reject the request (must be from
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* a duplicate node).
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*/
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if (signature != n_ptr->signature) {
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if (n_ptr->working_links == 0) {
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struct tipc_link *curr_link;
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int i;
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for (i = 0; i < MAX_BEARERS; i++) {
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curr_link = n_ptr->links[i];
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if (curr_link) {
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memset(&curr_link->media_addr, 0,
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sizeof(media_addr));
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tipc_link_reset(curr_link);
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}
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}
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addr_mismatch = (link != NULL);
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} else if (tipc_link_is_up(link) && !addr_mismatch) {
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/* delayed rediscovery */
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} else {
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disc_dupl_alert(b_ptr, orig, &media_addr);
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tipc_node_unlock(n_ptr);
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return;
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}
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n_ptr->signature = signature;
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}
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/*
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* Ensure requesting node's media address is correct
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*
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* If media address doesn't match and the link is working, reject the
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* request (must be from a duplicate node).
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*
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* If media address doesn't match and the link is not working, accept
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* the new media address and reset the link to ensure it starts up
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* cleanly.
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*/
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if (addr_mismatch) {
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if (tipc_link_is_up(link)) {
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disc_dupl_alert(b_ptr, orig, &media_addr);
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tipc_node_unlock(n_ptr);
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return;
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} else {
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memcpy(&link->media_addr, &media_addr,
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sizeof(media_addr));
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tipc_link_reset(link);
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}
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}
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/* Create a link endpoint for this bearer, if necessary */
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if (!link) {
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link = tipc_link_create(n_ptr, b_ptr, &media_addr);
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if (!link) {
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tipc_node_unlock(n_ptr);
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return;
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}
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}
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/* Accept discovery message & send response, if necessary */
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link_fully_up = link_working_working(link);
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if ((type == DSC_REQ_MSG) && !link_fully_up) {
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rbuf = tipc_disc_init_msg(DSC_RESP_MSG, orig, b_ptr);
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if (rbuf) {
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tipc_bearer_send(b_ptr, rbuf, &media_addr);
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kfree_skb(rbuf);
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}
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}
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tipc_node_unlock(n_ptr);
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}
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/**
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* disc_update - update frequency of periodic link setup requests
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* @req: ptr to link request structure
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*
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* Reinitiates discovery process if discovery object has no associated nodes
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* and is either not currently searching or is searching at a slow rate
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*/
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static void disc_update(struct tipc_link_req *req)
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{
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if (!req->num_nodes) {
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if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) ||
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(req->timer_intv > TIPC_LINK_REQ_FAST)) {
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req->timer_intv = TIPC_LINK_REQ_INIT;
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k_start_timer(&req->timer, req->timer_intv);
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}
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}
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}
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/**
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* tipc_disc_add_dest - increment set of discovered nodes
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* @req: ptr to link request structure
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*/
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void tipc_disc_add_dest(struct tipc_link_req *req)
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{
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spin_lock_bh(&req->lock);
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req->num_nodes++;
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spin_unlock_bh(&req->lock);
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}
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/**
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* tipc_disc_remove_dest - decrement set of discovered nodes
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* @req: ptr to link request structure
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*/
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void tipc_disc_remove_dest(struct tipc_link_req *req)
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{
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spin_lock_bh(&req->lock);
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req->num_nodes--;
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disc_update(req);
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spin_unlock_bh(&req->lock);
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}
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/**
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* disc_timeout - send a periodic link setup request
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* @req: ptr to link request structure
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*
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* Called whenever a link setup request timer associated with a bearer expires.
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*/
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static void disc_timeout(struct tipc_link_req *req)
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{
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int max_delay;
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spin_lock_bh(&req->lock);
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/* Stop searching if only desired node has been found */
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if (tipc_node(req->domain) && req->num_nodes) {
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req->timer_intv = TIPC_LINK_REQ_INACTIVE;
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goto exit;
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}
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/*
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* Send discovery message, then update discovery timer
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*
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* Keep doubling time between requests until limit is reached;
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* hold at fast polling rate if don't have any associated nodes,
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* otherwise hold at slow polling rate
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*/
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tipc_bearer_send(req->bearer, req->buf, &req->dest);
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req->timer_intv *= 2;
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if (req->num_nodes)
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max_delay = TIPC_LINK_REQ_SLOW;
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else
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max_delay = TIPC_LINK_REQ_FAST;
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if (req->timer_intv > max_delay)
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req->timer_intv = max_delay;
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k_start_timer(&req->timer, req->timer_intv);
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exit:
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spin_unlock_bh(&req->lock);
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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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* @b_ptr: 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 tipc_bearer *b_ptr, struct tipc_media_addr *dest,
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u32 dest_domain)
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{
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struct tipc_link_req *req;
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req = kmalloc(sizeof(*req), GFP_ATOMIC);
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if (!req)
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return -ENOMEM;
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req->buf = tipc_disc_init_msg(DSC_REQ_MSG, dest_domain, b_ptr);
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if (!req->buf) {
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kfree(req);
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return -ENOMSG;
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}
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memcpy(&req->dest, dest, sizeof(*dest));
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req->bearer = b_ptr;
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req->domain = dest_domain;
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req->num_nodes = 0;
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req->timer_intv = TIPC_LINK_REQ_INIT;
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spin_lock_init(&req->lock);
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k_init_timer(&req->timer, (Handler)disc_timeout, (unsigned long)req);
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k_start_timer(&req->timer, req->timer_intv);
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b_ptr->link_req = req;
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tipc_bearer_send(req->bearer, req->buf, &req->dest);
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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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* @req: ptr to link request structure
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*/
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void tipc_disc_delete(struct tipc_link_req *req)
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{
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k_cancel_timer(&req->timer);
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k_term_timer(&req->timer);
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kfree_skb(req->buf);
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kfree(req);
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}
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