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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) 2007-2009 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 <stdexcept>
#include <iostream>
#include <cstdio> // for std::memcpy
#include "encryptedPacket.h"
#include "endian.h"
#include "datatypes.h"
#include "log.h"
#include "anytunError.h"
EncryptedPacket::EncryptedPacket(u_int32_t payload_length, u_int32_t auth_tag_length, bool allow_realloc)
: Buffer(payload_length + sizeof(struct HeaderStruct), allow_realloc), auth_tag_length_(auth_tag_length)
{
header_ = reinterpret_cast<struct HeaderStruct*>(buf_);
payload_ = buf_ + sizeof(struct HeaderStruct);
auth_tag_ = NULL;
if(header_)
{
header_->seq_nr = 0;
header_->sender_id = 0;
header_->mux = 0;
}
}
u_int32_t EncryptedPacket::getHeaderLength()
{
return sizeof(struct HeaderStruct);
}
seq_nr_t EncryptedPacket::getSeqNr() const
{
if(header_)
return SEQ_NR_T_NTOH(header_->seq_nr);
return 0;
}
sender_id_t EncryptedPacket::getSenderId() const
{
if(header_)
return SENDER_ID_T_NTOH(header_->sender_id);
return 0;
}
mux_t EncryptedPacket::getMux() const
{
if(header_)
return MUX_T_NTOH(header_->mux);
return 0;
}
void EncryptedPacket::setSeqNr(seq_nr_t seq_nr)
{
if(header_)
header_->seq_nr = SEQ_NR_T_HTON(seq_nr);
}
void EncryptedPacket::setSenderId(sender_id_t sender_id)
{
if(header_)
header_->sender_id = SENDER_ID_T_HTON(sender_id);
}
void EncryptedPacket::setMux(mux_t mux)
{
if(header_)
header_->mux = MUX_T_HTON(mux);
}
void EncryptedPacket::setHeader(seq_nr_t seq_nr, sender_id_t sender_id, mux_t mux)
{
if(!header_)
return;
header_->seq_nr = SEQ_NR_T_HTON(seq_nr);
header_->sender_id = SENDER_ID_T_HTON(sender_id);
header_->mux = MUX_T_HTON(mux);
}
u_int32_t EncryptedPacket::getPayloadLength() const
{
if(!payload_)
return 0;
if(!auth_tag_)
return (length_ > sizeof(struct HeaderStruct)) ? (length_ - sizeof(struct HeaderStruct)) : 0;
return (length_ > (sizeof(struct HeaderStruct) + auth_tag_length_)) ? (length_ - sizeof(struct HeaderStruct) - auth_tag_length_) : 0;
}
void EncryptedPacket::setPayloadLength(u_int32_t payload_length)
{
Buffer::setLength(payload_length + sizeof(struct HeaderStruct));
// depending on allow_realloc buf_ may point to another address
// therefore in this case reinit() gets called by Buffer::setLength()
}
void EncryptedPacket::reinit()
{
header_ = reinterpret_cast<struct HeaderStruct*>(buf_);
payload_ = buf_ + sizeof(struct HeaderStruct);
if(length_ <= (sizeof(struct HeaderStruct)))
payload_ = NULL;
if(length_ < (sizeof(struct HeaderStruct))) {
header_ = NULL;
AnytunError::throwErr() << "encrypted packet can't be initialized, buffer is too small";
}
if(auth_tag_)
{
if(length_ < (sizeof(struct HeaderStruct) + auth_tag_length_)) {
auth_tag_ = NULL;
AnytunError::throwErr() << "auth-tag can't be enabled, buffer is too small";
}
auth_tag_ = buf_ + length_ - auth_tag_length_;
}
}
u_int8_t* EncryptedPacket::getPayload()
{
return payload_;
}
u_int8_t* EncryptedPacket::getAuthenticatedPortion()
{
return buf_;
}
u_int32_t EncryptedPacket::getAuthenticatedPortionLength()
{
if(!buf_)
return 0;
if(!auth_tag_)
return length_;
return (length_ > auth_tag_length_) ? (length_ - auth_tag_length_) : 0;
}
void EncryptedPacket::withAuthTag(bool b)
{
if((b && auth_tag_) || (!b && !auth_tag_))
return;
if(b)
{
if(length_ < (sizeof(struct HeaderStruct) + auth_tag_length_))
AnytunError::throwErr() << "auth-tag can't be enabled, buffer is too small";
auth_tag_ = buf_ + length_ - auth_tag_length_;
}
else
auth_tag_ = NULL;
}
void EncryptedPacket::addAuthTag()
{
if(auth_tag_)
return;
auth_tag_ = buf_; // will be set to the correct value @ reinit
setLength(length_ + auth_tag_length_);
if(auth_tag_ == buf_) // reinit was not called by setLength
reinit();
}
void EncryptedPacket::removeAuthTag()
{
if(!auth_tag_)
return;
auth_tag_ = NULL;
setLength(length_ - auth_tag_length_);
}
u_int8_t* EncryptedPacket::getAuthTag()
{
return auth_tag_;
}
u_int32_t EncryptedPacket::getAuthTagLength()
{
if(auth_tag_)
return auth_tag_length_;
return 0;
}
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