1 files changed, 215 insertions, 0 deletions
diff --git a/src/encryptedPacket.cpp b/src/encryptedPacket.cpp
new file mode 100644
index 0000000..c0221e9
--- /dev/null
+++ b/src/encryptedPacket.cpp
@@ -0,0 +1,215 @@
+/*
+ *  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 anytun.org <satp@wirdorange.org>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program 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 this program (see the file COPYING included with this
+ *  distribution); if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <stdexcept>
+#include <iostream>
+#include <arpa/inet.h>
+#include <cstdio>       // for std::memcpy
+
+#include "encryptedPacket.h"
+#include "datatypes.h"
+#include "log.h"
+
+EncryptedPacket::EncryptedPacket(u_int32_t payload_length, bool allow_realloc)
+  : Buffer(payload_length + sizeof(struct HeaderStruct), allow_realloc)
+{
+  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;
+  }
+}
+
+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) + AUTHTAG_SIZE)) ? (length_ - sizeof(struct HeaderStruct) - AUTHTAG_SIZE) : 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;
+    throw std::runtime_error("packet can't be initialized, buffer is too small"); 
+  }  
+  
+  if(auth_tag_)
+  {
+    if(length_ < (sizeof(struct HeaderStruct) + AUTHTAG_SIZE)) {
+      auth_tag_ = NULL;
+      throw std::runtime_error("auth-tag can't be enabled, buffer is too small"); 
+    }
+    auth_tag_ = buf_ + length_ - AUTHTAG_SIZE;
+  }  
+}
+
+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_ > AUTHTAG_SIZE) ? (length_ - AUTHTAG_SIZE) : 0;
+}
+
+void EncryptedPacket::withAuthTag(bool b)
+{
+  if((b && auth_tag_) || (!b && !auth_tag_))
+    return;
+  
+  if(b)
+  {
+    if(length_ < (sizeof(struct HeaderStruct) + AUTHTAG_SIZE))
+      throw std::runtime_error("auth-tag can't be enabled, buffer is too small");
+    
+    auth_tag_ = buf_ + length_ - AUTHTAG_SIZE;
+  }
+  else
+    auth_tag_ = NULL;
+}
+
+void EncryptedPacket::addAuthTag()
+{
+  if(auth_tag_)
+    return;
+
+  auth_tag_ = buf_; // will be set to the correct value @ reinit
+  setLength(length_ + AUTHTAG_SIZE);
+  if(auth_tag_ == buf_) // reinit was not called by setLength
+    reinit();
+}
+
+void EncryptedPacket::removeAuthTag()
+{
+  if(!auth_tag_)
+    return;
+
+  auth_tag_ = NULL;
+  setLength(length_ - AUTHTAG_SIZE);
+}
+
+u_int8_t* EncryptedPacket::getAuthTag()
+{
+  return auth_tag_;
+}
+
+u_int32_t EncryptedPacket::getAuthTagLength()
+{
+  if(auth_tag_)
+    return AUTHTAG_SIZE;
+
+  return 0;
+}