encryptedPacket.cpp

   1 /*
   2  *  anytun
   3  *
   4  *  The secure anycast tunneling protocol (satp) defines a protocol used
   5  *  for communication between any combination of unicast and anycast
   6  *  tunnel endpoints.  It has less protocol overhead than IPSec in Tunnel
   7  *  mode and allows tunneling of every ETHER TYPE protocol (e.g.
   8  *  ethernet, ip, arp ...). satp directly includes cryptography and
   9  *  message authentication based on the methodes used by SRTP.  It is
  10  *  intended to deliver a generic, scaleable and secure solution for
  11  *  tunneling and relaying of packets of any protocol.
  12  *
  13  *
  14  *  Copyright (C) 2007 anytun.org <satp@wirdorange.org>
  15  *
  16  *  This program is free software; you can redistribute it and/or modify
  17  *  it under the terms of the GNU General Public License version 2
  18  *  as published by the Free Software Foundation.
  19  *
  20  *  This program is distributed in the hope that it will be useful,
  21  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  *  GNU General Public License for more details.
  24  *
  25  *  You should have received a copy of the GNU General Public License
  26  *  along with this program (see the file COPYING included with this
  27  *  distribution); if not, write to the Free Software Foundation, Inc.,
  28  *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  29  */
  30
  31 #include <stdexcept>
  32 #include <iostream>
  33 #include <arpa/inet.h>
  34 #include <cstdio>       // for std::memcpy
  35
  36 #include "encryptedPacket.h"
  37 #include "datatypes.h"
  38 #include "authTag.h"
  39 #include "log.h"
  40
  41 // TODO: fix auth_tag stuff
  42 EncryptedPacket::EncryptedPacket(u_int32_t payload_length, bool allow_realloc)
  43   : Buffer(payload_length + sizeof(struct HeaderStruct), allow_realloc)
  44 {
  45   header_ = reinterpret_cast<struct HeaderStruct*>(buf_);
  46   payload_ = buf_ + sizeof(struct HeaderStruct);    // TODO: fix auth_tag stuff
  47   auth_tag_ = NULL;                                 // TODO: fix auth_tag stuff
  48   if(header_)
  49   {
  50     header_->seq_nr = 0;
  51     header_->sender_id = 0;
  52     header_->mux = 0;
  53   }
  54 }
  55
  56 seq_nr_t EncryptedPacket::getSeqNr() const
  57 {
  58   if(header_)
  59     return SEQ_NR_T_NTOH(header_->seq_nr);
  60
  61   return 0;
  62 }
  63
  64 sender_id_t EncryptedPacket::getSenderId() const
  65 {
  66   if(header_)
  67     return SENDER_ID_T_NTOH(header_->sender_id);
  68
  69   return 0;
  70 }
  71
  72 mux_t EncryptedPacket::getMux() const
  73 {
  74   if(header_)
  75     return MUX_T_NTOH(header_->mux);
  76
  77   return 0;
  78 }
  79
  80 void EncryptedPacket::setSeqNr(seq_nr_t seq_nr)
  81 {
  82   if(header_)
  83     header_->seq_nr = SEQ_NR_T_HTON(seq_nr);
  84 }
  85
  86 void EncryptedPacket::setSenderId(sender_id_t sender_id)
  87 {
  88   if(header_)
  89     header_->sender_id = SENDER_ID_T_HTON(sender_id);
  90 }
  91
  92 void EncryptedPacket::setMux(mux_t mux)
  93 {
  94   if(header_)
  95     header_->mux = MUX_T_HTON(mux);
  96 }
  97
  98 void EncryptedPacket::setHeader(seq_nr_t seq_nr, sender_id_t sender_id, mux_t mux)
  99 {
 100   if(!header_)
 101     return;
 102
 103   header_->seq_nr = SEQ_NR_T_HTON(seq_nr);
 104   header_->sender_id = SENDER_ID_T_HTON(sender_id);
 105   header_->mux = MUX_T_HTON(mux);
 106 }
 107
 108 u_int32_t EncryptedPacket::getPayloadLength() const
 109 {
 110   return (length_ > sizeof(struct HeaderStruct)) ? (length_ - sizeof(struct HeaderStruct)) : 0;  // TODO: fix auth_tag stuff
 111 }
 112
 113 void EncryptedPacket::setPayloadLength(u_int32_t payload_length)
 114 {
 115   Buffer::setLength(payload_length + sizeof(struct HeaderStruct));
 116       // depending on allow_realloc buf_ may point to another address
 117       // therefore in this case reinit() gets called by Buffer::setLength()
 118 }
 119
 120 void EncryptedPacket::reinit()
 121 {
 122   Buffer::reinit();
 123   header_ = reinterpret_cast<struct HeaderStruct*>(buf_);
 124   payload_ = buf_ + sizeof(struct HeaderStruct);    // TODO: fix auth_tag stuff
 125   auth_tag_ = NULL;                                 // TODO: fix auth_tag stuff
 126 }
 127
 128 u_int8_t* EncryptedPacket::getPayload()
 129 {
 130   return payload_;
 131 }
 132
 133
 134
 135
 136
 137
 138 // TODO: fix auth_tag stuff
 139
 140 bool EncryptedPacket::hasAuthTag() const
 141 {
 142 //   if( auth_tag_ == NULL )
 143      return false;
 144 //   return true;
 145 }
 146
 147 void EncryptedPacket::withAuthTag(bool b)
 148 {
 149 //   if( b && (auth_tag_ != NULL) )
 150 //     throw std::runtime_error("packet already has auth tag function enabled");
 151 //              //TODO: return instead?
 152 //   if( ! b && (auth_tag_ == NULL) )
 153 //     throw std::runtime_error("packet already has auth tag function disabled");
 154 //              //TODO: return instead?
 155
 156 //   if( b ) {
 157 //     auth_tag_ = reinterpret_cast<AuthTag*>( buf_ + sizeof(struct HeaderStruct) );
 158 //     payload_ = payload_ + AUTHTAG_SIZE;
 159 //     length_ -= AUTHTAG_SIZE;
 160 //     max_length_ -= AUTHTAG_SIZE;
 161 //   } else {
 162 //     payload_ = reinterpret_cast<u_int8_t*>( auth_tag_ );
 163 //     length_ += AUTHTAG_SIZE;
 164 //     max_length_ += AUTHTAG_SIZE;
 165 //     auth_tag_ = NULL;
 166 //   }
 167 }
 168
 169 void EncryptedPacket::setAuthTag(AuthTag& tag)
 170 {
 171 //   if( auth_tag_ == NULL )
 172 //     throw std::runtime_error("auth tag not enabled");
 173
 174 //   if( tag == AuthTag(0) )
 175 //     return;
 176
 177 //   if( tag.getLength() != AUTHTAG_SIZE )
 178 //     throw std::length_error("authtag length mismatch with AUTHTAG_SIZE");
 179
 180 //   std::memcpy( auth_tag_, tag.getBuf(), AUTHTAG_SIZE );
 181 }
 182
 183 AuthTag EncryptedPacket::getAuthTag() const
 184 {
 185 //   if( auth_tag_ == NULL )
 186 //     throw std::runtime_error("auth tag not enabled");
 187
 188   AuthTag at(AUTHTAG_SIZE);
 189 //  std::memcpy(at, auth_tag_, AUTHTAG_SIZE );
 190   return at;
 191 }