src/plainPacket.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) 2007-2008 Othmar Gsenger, Erwin Nindl,
  15  *                          Christian Pointner <satp@wirdorange.org>
  16  *
  17  *  This file is part of Anytun.
  18  *
  19  *  Anytun is free software: you can redistribute it and/or modify
  20  *  it under the terms of the GNU General Public License version 3 as
  21  *  published by the Free Software Foundation.
  22  *
  23  *  Anytun is distributed in the hope that it will be useful,
  24  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  25  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  26  *  GNU General Public License for more details.
  27  *
  28  *  You should have received a copy of the GNU General Public License
  29  *  along with anytun.  If not, see <http://www.gnu.org/licenses/>.
  30  */
  31
  32 #include <stdexcept>
  33 #include <iostream>
  34 #include "datatypes.h"
  35 #include "endian.h"
  36 #include "plainPacket.h"
  37
  38 PlainPacket::PlainPacket(u_int32_t payload_length, bool allow_realloc) : Buffer(payload_length + sizeof(payload_type_t), allow_realloc)
  39 {
  40   payload_type_ = reinterpret_cast<payload_type_t*>(buf_);
  41   payload_ = buf_ + sizeof(payload_type_t);
  42   *payload_type_ = 0;
  43 }
  44
  45 u_int32_t PlainPacket::getHeaderLength()
  46 {
  47   return sizeof(payload_type_t);
  48 }
  49
  50 payload_type_t PlainPacket::getPayloadType() const
  51 {
  52   if(payload_type_)
  53     return PAYLOAD_TYPE_T_NTOH(*payload_type_);
  54
  55   return 0;
  56 }
  57
  58 void PlainPacket::setPayloadType(payload_type_t payload_type)
  59 {
  60   if(!payload_type_)
  61     return;
  62
  63   if(payload_type == PAYLOAD_TYPE_TUN) {
  64     if(!payload_) {
  65       *payload_type_ = PAYLOAD_TYPE_T_HTON(PAYLOAD_TYPE_TUN);
  66       return;
  67     }
  68
  69     char * ip_version_ptr = reinterpret_cast<char *>(payload_);
  70                 char ip_version = ip_version_ptr[0];
  71                 ip_version >>=4;
  72     if(ip_version == 4)
  73       *payload_type_ = PAYLOAD_TYPE_T_HTON(PAYLOAD_TYPE_TUN4);
  74     else if(ip_version == 6)
  75       *payload_type_ = PAYLOAD_TYPE_T_HTON(PAYLOAD_TYPE_TUN6);
  76   }
  77   else
  78     *payload_type_ = PAYLOAD_TYPE_T_HTON(payload_type);
  79 }
  80
  81 u_int32_t PlainPacket::getPayloadLength() const
  82 {
  83   if(!payload_)
  84     return 0;
  85
  86   return (length_ > sizeof(payload_type_t)) ? (length_ - sizeof(payload_type_t)) : 0;
  87 }
  88
  89 void PlainPacket::setPayloadLength(u_int32_t payload_length)
  90 {
  91   Buffer::setLength(payload_length + sizeof(payload_type_t));
  92       // depending on allow_realloc buf_ may point to another address
  93       // therefore in this case reinit() gets called by Buffer::setLength()
  94 }
  95
  96 void PlainPacket::reinit()
  97 {
  98   payload_type_ = reinterpret_cast<payload_type_t*>(buf_);
  99   payload_ = buf_ + sizeof(payload_type_t);
 100
 101   if(length_ <= (sizeof(payload_type_t)))
 102     payload_ = NULL;
 103
 104   if(length_ < (sizeof(payload_type_t))) {
 105     payload_type_ = NULL;
 106     throw std::runtime_error("packet can't be initialized, buffer is too small");
 107   }
 108
 109 }
 110
 111 u_int8_t* PlainPacket::getPayload()
 112 {
 113   return payload_;
 114 }
 115
 116 /*
 117 NetworkAddress PlainPacket::getSrcAddr() const
 118 {
 119   if(!payload_type_ || !payload_)
 120     return NetworkAddress();
 121
 122   payload_type_t type = PAYLOAD_TYPE_T_NTOH(*payload_type_);
 123
 124   if(type == PAYLOAD_TYPE_TAP) // Ehternet
 125   {
 126         // TODO
 127     return NetworkAddress();
 128   }
 129   else if(type == PAYLOAD_TYPE_TUN4) // IPv4
 130   {
 131     if(length_ < (sizeof(payload_type_t)+sizeof(struct ip)))
 132       return NetworkAddress();
 133     struct ip* hdr = reinterpret_cast<struct ip*>(payload_);
 134     return NetworkAddress(hdr->ip_src);
 135   }
 136   else if(type == PAYLOAD_TYPE_TUN6) // IPv6
 137   {
 138     if(length_ < (sizeof(payload_type_t)+sizeof(struct ip6_hdr)))
 139       return NetworkAddress();
 140     struct ip6_hdr* hdr = reinterpret_cast<struct ip6_hdr*>(payload_);
 141     return NetworkAddress(hdr->ip6_src);
 142   }
 143   return NetworkAddress();
 144 }*/
 145
 146 NetworkAddress PlainPacket::getDstAddr() const
 147 {
 148         if(!payload_type_ || !payload_)
 149                 return NetworkAddress();
 150
 151         payload_type_t type = PAYLOAD_TYPE_T_NTOH(*payload_type_);
 152
 153         if(type == PAYLOAD_TYPE_TAP) // Ehternet
 154         {
 155                 // TODO
 156                 return NetworkAddress();
 157         }
 158         else if(type == PAYLOAD_TYPE_TUN4) // IPv4
 159         {
 160                 if(length_ < (sizeof(payload_type_t)+5*4))
 161                         return NetworkAddress();
 162                 char * hdr = reinterpret_cast<char *>(payload_);
 163                 boost::asio::ip::address_v4::bytes_type ip_octets;
 164                 for (int i=0; i<4;i++)
 165                         ip_octets[i]=hdr[4*4+i];
 166                 return NetworkAddress(boost::asio::ip::address_v4(ip_octets));
 167         }
 168         else if(type == PAYLOAD_TYPE_TUN6) // IPv6
 169         {
 170                 if(length_ < (sizeof(payload_type_t)+2*16+2*4))
 171                         return NetworkAddress();
 172                 char * hdr = reinterpret_cast<char *>(payload_);
 173                 boost::asio::ip::address_v6::bytes_type ip_octets;
 174                 for (int i=0; i<16;i++)
 175                         ip_octets[i]=hdr[2*4+16+i];
 176                 return NetworkAddress(boost::asio::ip::address_v6(ip_octets));
 177         }
 178         return NetworkAddress();
 179 }