xwords/xwords4/relay/udpager.cpp
Eric House bfc617720e add isCurrent() method on UDP addresses based on how long it's been
since we've received data from the same source, and use to drop
packets in response to reads that are older than when the test says
the endpoint of the address changed.
2013-07-23 06:21:57 -07:00

107 lines
3.5 KiB
C++

/* -*- compile-command: "make -k -j3"; -*- */
/*
* Copyright 2013 by Eric House (xwords@eehouse.org). All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <glib.h>
#include "udpager.h"
#include "configs.h"
#include "mlock.h"
static UDPAger* s_instance = NULL;
/* static */ UDPAger*
UDPAger::Get()
{
if ( NULL == s_instance ) {
s_instance = new UDPAger();
}
return s_instance;
} /* Get */
UDPAger::UDPAger()
{
if ( !RelayConfigs::GetConfigs()-> GetValueFor( "UDP_RECYLE_INTERVAL",
&m_maxInterval ) ) {
assert(0);
}
logf( XW_LOGINFO, "read %d from configs for UDP_RECYLE_INTERVAL",
m_maxInterval );
m_maxInterval *= 1000; // make it milliseconds
pthread_mutex_init( &m_addrTimeMapLock, NULL );
}
// An address is valid as long as we keep hearing from it within a certain
// frequency. When we hear from it but it's been too long, assume it's new
// and give it a new timestamp.
void
UDPAger::Refresh( const AddrInfo* addr )
{
const AddrInfo::AddrUnion* saddr = addr->saddr();
uint32_t readWhen = addr->created();
gchar* b64 = g_base64_encode( (unsigned char*)&saddr->u.addr,
sizeof(saddr->u.addr) );
MutexLock ml( &m_addrTimeMapLock );
map<AddrInfo::AddrUnion, AgePair*>::iterator iter =
m_addrTimeMap.find( *saddr );
if ( m_addrTimeMap.end() == iter ) { // it's new; just insert
AgePair* ap = new AgePair( readWhen, readWhen );
m_addrTimeMap.insert( pair<AddrInfo::AddrUnion,
AgePair*>(*saddr, ap ) );
logf( XW_LOGINFO, "%s: adding '%s'", __func__, b64 );
} else {
AgePair* ap = iter->second;
assert( ap->lastSeen() <= readWhen );
int interval = readWhen - ap->lastSeen();
if ( m_maxInterval >= interval ) {
logf( XW_LOGINFO, "%s: refreshing '%s'; last seen %d "
"milliseconds ago", __func__, b64, interval );
ap->update( readWhen );
} else {
logf( XW_LOGINFO, "%s: RESETTING '%s'; last seen %d "
"milliseconds ago", __func__, b64, interval );
delete ap;
iter->second = new AgePair( readWhen, readWhen );
}
}
g_free( b64 );
}
bool
UDPAger::IsCurrent( const AddrInfo* addr )
{
const AddrInfo::AddrUnion* saddr = addr->saddr();
uint32_t readWhen = addr->created();
MutexLock ml( &m_addrTimeMapLock );
map<AddrInfo::AddrUnion, AgePair*>::const_iterator iter =
m_addrTimeMap.find( *saddr );
assert( m_addrTimeMap.end() != iter );
AgePair* ap = iter->second;
bool result = readWhen >= ap->created();
if ( !result ) {
logf( XW_LOGINFO, "%s() => %d", __func__, result );
}
return result;
}