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/*
* anytun
*
* The secure anycast tunneling protocol (satp) defines a protocol used
* for communication between any combination of unicast and anycast
* tunnel endpoints. It has less protocol overhead than IPSec in Tunnel
* mode and allows tunneling of every ETHER TYPE protocol (e.g.
* ethernet, ip, arp ...). satp directly includes cryptography and
* message authentication based on the methodes used by SRTP. It is
* intended to deliver a generic, scaleable and secure solution for
* tunneling and relaying of packets of any protocol.
*
*
* Copyright (C) 2007-2008 Othmar Gsenger, Erwin Nindl,
* Christian Pointner <satp@wirdorange.org>
*
* This file is part of Anytun.
*
* Anytun 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 3 of the License, or
* any later version.
*
* Anytun 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 anytun. If not, see <http://www.gnu.org/licenses/>.
*/
#include "threadUtils.hpp"
#include "datatypes.h"
#include "seqWindow.h"
SeqWindowElement::SeqWindowElement()
{
window_ = NULL;
pos_ = 0;
max_ = 0;
}
SeqWindowElement::~SeqWindowElement()
{
if(window_)
delete[] window_;
}
void SeqWindowElement::init(window_size_t w, seq_nr_t m)
{
if(window_)
delete[] window_;
window_ = new u_int8_t[w];
memset(window_, 0, w);
pos_ = 0;
max_ = m;
window_[pos_] = 1;
}
SeqWindow::SeqWindow(window_size_t w) : window_size_(w)
{
}
SeqWindow::~SeqWindow()
{
}
bool SeqWindow::checkAndAdd(sender_id_t sender, seq_nr_t seq_nr)
{
Lock lock(mutex_);
if (!window_size_)
return false;
SenderMap::iterator s = sender_.find(sender);
if(s == sender_.end()) {
sender_[sender].init(window_size_, seq_nr);
return false;
}
int shifted = 0;
if(s->second.max_ < window_size_) {
s->second.max_ += SEQ_NR_MAX/2;
seq_nr += SEQ_NR_MAX/2;
shifted = 1;
}
else if(s->second.max_ > (SEQ_NR_MAX - window_size_)) {
s->second.max_ -= SEQ_NR_MAX/2;
seq_nr -= SEQ_NR_MAX/2;
shifted = 2;
}
seq_nr_t min = s->second.max_ - window_size_ + 1;
if(seq_nr < min || seq_nr == s->second.max_) {
if(shifted == 1)
s->second.max_ -= SEQ_NR_MAX/2;
else if(shifted == 2)
s->second.max_ += SEQ_NR_MAX/2;
return true;
}
if(seq_nr > s->second.max_) {
seq_nr_t diff = seq_nr - s->second.max_;
if(diff >= window_size_)
diff = window_size_;
window_size_t new_pos = s->second.pos_ + diff;
if(new_pos >= window_size_) {
new_pos -= window_size_;
if(s->second.pos_ < window_size_ - 1)
memset(&(s->second.window_[s->second.pos_ + 1]), 0, window_size_ - s->second.pos_ - 1);
memset(s->second.window_, 0, new_pos);
}
else {
memset(&(s->second.window_[s->second.pos_ + 1]), 0, diff);
}
s->second.pos_ = new_pos;
s->second.window_[s->second.pos_] = 1;
s->second.max_ = seq_nr;
if(shifted == 1)
s->second.max_ -= SEQ_NR_MAX/2;
else if(shifted == 2)
s->second.max_ += SEQ_NR_MAX/2;
return false;
}
seq_nr_t diff = s->second.max_ - seq_nr;
window_size_t pos = diff > s->second.pos_ ? s->second.pos_ + window_size_ : s->second.pos_;
pos -= diff;
if(shifted == 1)
s->second.max_ -= SEQ_NR_MAX/2;
else if(shifted == 2)
s->second.max_ += SEQ_NR_MAX/2;
int ret = s->second.window_[pos];
s->second.window_[pos] = 1;
if(ret)
return true;
return false;
}
void SeqWindow::clear(sender_id_t sender)
{
Lock lock(mutex_);
sender_.erase(sender);
}
void SeqWindow::clear()
{
Lock lock(mutex_);
sender_.clear();
}
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