src/encrypted_packet.c

   1 /*
   2  *  uAnytun
   3  *
   4  *  uAnytun is a tiny implementation of SATP. Unlike Anytun which is a full
   5  *  featured implementation uAnytun has no support for multiple connections
   6  *  or synchronisation. It is a small single threaded implementation intended
   7  *  to act as a client on small platforms.
   8  *  The secure anycast tunneling protocol (satp) defines a protocol used
   9  *  for communication between any combination of unicast and anycast
  10  *  tunnel endpoints.  It has less protocol overhead than IPSec in Tunnel
  11  *  mode and allows tunneling of every ETHER TYPE protocol (e.g.
  12  *  ethernet, ip, arp ...). satp directly includes cryptography and
  13  *  message authentication based on the methodes used by SRTP.  It is
  14  *  intended to deliver a generic, scaleable and secure solution for
  15  *  tunneling and relaying of packets of any protocol.
  16  *
  17  *
  18  *  Copyright (C) 2007-2008 Christian Pointner <equinox@anytun.org>
  19  *
  20  *  This file is part of uAnytun.
  21  *
  22  *  uAnytun is free software: you can redistribute it and/or modify
  23  *  it under the terms of the GNU General Public License version 3 as
  24  *  published by the Free Software Foundation.
  25  *
  26  *  uAnytun is distributed in the hope that it will be useful,
  27  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  29  *  GNU General Public License for more details.
  30  *
  31  *  You should have received a copy of the GNU General Public License
  32  *  along with uAnytun. If not, see <http://www.gnu.org/licenses/>.
  33  */
  34
  35 #include "datatypes.h"
  36
  37 #include "encrypted_packet.h"
  38
  39 #include <stdlib.h>
  40 #include <string.h>
  41
  42 void encrypted_packet_init(encrypted_packet_t* packet, u_int32_t auth_tag_length)
  43 {
  44   if(!packet)
  45     return;
  46
  47   memset (packet, 0, sizeof(*packet));
  48   if(auth_tag_length > (ENCRYPTED_PACKET_SIZE_MAX - sizeof(encrypted_packet_header_t)))
  49     packet->auth_tag_length_ = ENCRYPTED_PACKET_SIZE_MAX - sizeof(encrypted_packet_header_t);
  50   else
  51     packet->auth_tag_length_ = auth_tag_length;
  52 }
  53
  54 u_int32_t encrypted_packet_get_minimum_length(encrypted_packet_t* packet)
  55 {
  56   if(!packet)
  57     return 0;
  58
  59   return (sizeof(encrypted_packet_header_t) + packet->auth_tag_length_);
  60 }
  61
  62 u_int8_t* encrypted_packet_get_packet(encrypted_packet_t* packet)
  63 {
  64   if(!packet)
  65     return NULL;
  66
  67   return packet->data_.buf_;
  68 }
  69
  70 u_int32_t encrypted_packet_get_length(encrypted_packet_t* packet)
  71 {
  72   if(!packet)
  73     return 0;
  74
  75   return (packet->payload_length_ + sizeof(encrypted_packet_header_t) + packet->auth_tag_length_);
  76 }
  77
  78 void encrypted_packet_set_length(encrypted_packet_t* packet, u_int32_t len)
  79 {
  80   if(!packet)
  81     return;
  82
  83   if(len > ENCRYPTED_PACKET_SIZE_MAX)
  84     len = ENCRYPTED_PACKET_SIZE_MAX - sizeof(encrypted_packet_header_t) - packet->auth_tag_length_;
  85   else if(len < (sizeof(encrypted_packet_header_t) + packet->auth_tag_length_))
  86     len = 0;
  87   else
  88     len -= (sizeof(encrypted_packet_header_t) + packet->auth_tag_length_);
  89
  90   packet->payload_length_ = len;
  91 }
  92
  93 u_int8_t* encrypted_packet_get_payload(encrypted_packet_t* packet)
  94 {
  95   if(!packet || !packet->payload_length_)
  96     return NULL;
  97
  98   return (packet->data_.buf_ + sizeof(encrypted_packet_header_t));
  99 }
 100
 101 u_int32_t encrypted_packet_get_payload_length(encrypted_packet_t* packet)
 102 {
 103   if(!packet)
 104     return 0;
 105
 106   return packet->payload_length_;
 107 }
 108
 109 void encrypted_packet_set_payload_length(encrypted_packet_t* packet, u_int32_t len)
 110 {
 111   if(!packet)
 112     return;
 113
 114   if(len > (ENCRYPTED_PACKET_SIZE_MAX - sizeof(encrypted_packet_header_t) - packet->auth_tag_length_))
 115     len = ENCRYPTED_PACKET_SIZE_MAX - sizeof(encrypted_packet_header_t) - packet->auth_tag_length_;
 116
 117   packet->payload_length_ = len;
 118 }
 119
 120 u_int8_t* encrypted_packet_get_auth_portion(encrypted_packet_t* packet)
 121 {
 122   if(!packet)
 123     return NULL;
 124
 125   return packet->data_.buf_;
 126 }
 127
 128 u_int32_t encrypted_packet_get_auth_portion_length(encrypted_packet_t* packet)
 129 {
 130   if(!packet)
 131     return 0;
 132
 133   return  packet->payload_length_ + sizeof(encrypted_packet_header_t);
 134 }
 135
 136
 137 u_int8_t* encrypted_packet_get_auth_tag(encrypted_packet_t* packet)
 138 {
 139   if(!packet || !packet->auth_tag_length_)
 140     return NULL;
 141
 142   return (packet->data_.buf_ + sizeof(encrypted_packet_header_t) + packet->payload_length_);
 143 }
 144
 145 u_int32_t encrypted_packet_get_auth_tag_length(encrypted_packet_t* packet)
 146 {
 147   if(!packet)
 148     return 0;
 149
 150   return packet->auth_tag_length_;
 151 }
 152
 153
 154 seq_nr_t encrypted_packet_get_seq_nr(encrypted_packet_t* packet)
 155 {
 156   if(!packet)
 157     return 0;
 158
 159   return SEQ_NR_T_NTOH(packet->data_.header_.seq_nr_);
 160 }
 161
 162 void encrypted_packet_set_seq_nr(encrypted_packet_t* packet, seq_nr_t seq_nr)
 163 {
 164   if(!packet)
 165     return;
 166
 167   packet->data_.header_.seq_nr_ = SEQ_NR_T_HTON(seq_nr);
 168 }
 169
 170 sender_id_t encrypted_packet_get_sender_id(encrypted_packet_t* packet)
 171 {
 172   if(!packet)
 173     return 0;
 174
 175   return SENDER_ID_T_NTOH(packet->data_.header_.sender_id_);
 176 }
 177
 178 void encrypted_packet_set_sender_id(encrypted_packet_t* packet, sender_id_t sender_id)
 179 {
 180   if(!packet)
 181     return;
 182
 183   packet->data_.header_.sender_id_ = SENDER_ID_T_HTON(sender_id);
 184 }
 185
 186 mux_t encrypted_packet_get_mux(encrypted_packet_t* packet)
 187 {
 188   if(!packet)
 189     return 0;
 190
 191   return MUX_T_NTOH(packet->data_.header_.mux_);
 192 }
 193
 194 void encrypted_packet_set_mux(encrypted_packet_t* packet, mux_t mux)
 195 {
 196   if(!packet)
 197     return;
 198
 199   packet->data_.header_.mux_ = MUX_T_HTON(mux);
 200 }