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/*
* Copyright (c) 2017, Matias Fontanini
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <tins/tcp_ip/data_tracker.h>
#ifdef TINS_HAVE_TCPIP
#include <tins/detail/sequence_number_helpers.h>
using std::move;
using Tins::Internals::seq_compare;
namespace Tins {
namespace TCPIP {
DataTracker::DataTracker()
: seq_number_(0), total_buffered_bytes_(0) {
}
DataTracker::DataTracker(uint32_t seq_number)
: seq_number_(seq_number), total_buffered_bytes_(0) {
}
bool DataTracker::process_payload(uint32_t seq, payload_type payload) {
const uint32_t chunk_end = seq + payload.size();
// If the end of the chunk ends before current sequence number, ignore it.
if (seq_compare(chunk_end, seq_number_) < 0) {
return false;
}
// If it starts before our sequence number, slice it
if (seq_compare(seq, seq_number_) < 0) {
const uint32_t diff = seq_number_ - seq;
payload.erase(
payload.begin(),
payload.begin() + diff
);
seq = seq_number_;
}
bool added_some = false;
// Store this payload
store_payload(seq, move(payload));
// Keep looping while the fragments seq is lower or equal to our seq
buffered_payload_type::iterator iter = buffered_payload_.find(seq_number_);
while (iter != buffered_payload_.end() && seq_compare(iter->first, seq_number_) <= 0) {
// Does this fragment start before our sequence number?
if (seq_compare(iter->first, seq_number_) < 0) {
uint32_t fragment_end = iter->first + iter->second.size();
int comparison = seq_compare(fragment_end, seq_number_);
// Does it end after our sequence number?
if (comparison > 0) {
// Then slice it
payload_type& payload = iter->second;
// First update this counter
total_buffered_bytes_ -= payload.size();
payload.erase(
payload.begin(),
payload.begin() + (seq_number_ - iter->first)
);
store_payload(seq_number_, move(iter->second));
iter = erase_iterator(iter);
}
else {
// Otherwise, we've seen this part of the payload. Erase it.
iter = erase_iterator(iter);
}
}
else {
// They're equal. Add this payload.
payload_.insert(
payload_.end(),
iter->second.begin(),
iter->second.end()
);
seq_number_ += iter->second.size();
iter = erase_iterator(iter);
added_some = true;
}
}
return added_some;
}
void DataTracker::advance_sequence(uint32_t seq) {
if (seq_compare(seq, seq_number_) <= 0) {
return;
}
for (auto it = buffered_payload_.begin(); it != buffered_payload_.end();) {
if (seq_compare(it->first, seq) <= 0) {
total_buffered_bytes_ -= it->second.size();
it = buffered_payload_.erase(it);
} else {
it++;
}
}
seq_number_ = seq;
}
uint32_t DataTracker::sequence_number() const {
return seq_number_;
}
void DataTracker::sequence_number(uint32_t seq) {
seq_number_ = seq;
}
const DataTracker::payload_type& DataTracker::payload() const {
return payload_;
}
DataTracker::payload_type& DataTracker::payload() {
return payload_;
}
const DataTracker::buffered_payload_type& DataTracker::buffered_payload() const {
return buffered_payload_;
}
DataTracker::buffered_payload_type& DataTracker::buffered_payload() {
return buffered_payload_;
}
uint32_t DataTracker::total_buffered_bytes() const {
return total_buffered_bytes_;
}
void DataTracker::store_payload(uint32_t seq, payload_type payload) {
buffered_payload_type::iterator iter = buffered_payload_.find(seq);
// New segment, store it
if (iter == buffered_payload_.end()) {
total_buffered_bytes_ += payload.size();
buffered_payload_.insert(make_pair(seq, move(payload)));
}
else if (iter->second.size() < payload.size()) {
// Increment by the diff between sizes
total_buffered_bytes_ += (payload.size() - iter->second.size());
// If we already have payload on this position but it's a shorter
// chunk than the new one, replace it
iter->second = move(payload);
}
}
DataTracker::buffered_payload_type::iterator
DataTracker::erase_iterator(buffered_payload_type::iterator iter) {
buffered_payload_type::iterator output = iter;
total_buffered_bytes_ -= iter->second.size();
++output;
buffered_payload_.erase(iter);
if (output == buffered_payload_.end()) {
output = buffered_payload_.begin();
}
return output;
}
} // TCPIP
} // Tins
#endif // TINS_HAVE_TCPIP
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