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 as published by
  24  *  the Free Software Foundation, either version 3 of the License, or
  25  *  any later version.
  26  *
  27  *  uAnytun is distributed in the hope that it will be useful,
  28  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  29  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  30  *  GNU General Public License for more details.
  31  *
  32  *  You should have received a copy of the GNU General Public License
  33  *  along with uAnytun. If not, see <http://www.gnu.org/licenses/>.
  34  */
  35
  36 #include "datatypes.h"
  37
  38 #include "encrypted_packet.h"
  39
  40 #include <stdlib.h>
  41 #include <string.h>
  42
  43 void encrypted_packet_init(encrypted_packet_t* packet, u_int32_t auth_tag_length)
  44 {
  45   if(!packet)
  46     return;
  47
  48   memset (packet, 0, sizeof(*packet));
  49   if(auth_tag_length > (ENCRYPTED_PACKET_SIZE_MAX - sizeof(encrypted_packet_header_t)))
  50     packet->auth_tag_length_ = ENCRYPTED_PACKET_SIZE_MAX - sizeof(encrypted_packet_header_t);
  51   else
  52     packet->auth_tag_length_ = auth_tag_length;
  53 }
  54
  55 u_int32_t encrypted_packet_get_minimum_length(encrypted_packet_t* packet)
  56 {
  57   if(!packet)
  58     return 0;
  59
  60   return (sizeof(encrypted_packet_header_t) + packet->auth_tag_length_);
  61 }
  62
  63 u_int8_t* encrypted_packet_get_packet(encrypted_packet_t* packet)
  64 {
  65   if(!packet)
  66     return NULL;
  67
  68   return packet->data_.buf_;
  69 }
  70
  71 u_int32_t encrypted_packet_get_length(encrypted_packet_t* packet)
  72 {
  73   if(!packet)
  74     return 0;
  75
  76   return (packet->payload_length_ + sizeof(encrypted_packet_header_t) + packet->auth_tag_length_);
  77 }
  78
  79 void encrypted_packet_set_length(encrypted_packet_t* packet, u_int32_t len)
  80 {
  81   if(!packet)
  82     return;
  83
  84   if(len > ENCRYPTED_PACKET_SIZE_MAX)
  85     len = ENCRYPTED_PACKET_SIZE_MAX - sizeof(encrypted_packet_header_t) - packet->auth_tag_length_;
  86   else if(len < (sizeof(encrypted_packet_header_t) + packet->auth_tag_length_))
  87     len = 0;
  88   else
  89     len -= (sizeof(encrypted_packet_header_t) + packet->auth_tag_length_);
  90
  91   packet->payload_length_ = len;
  92 }
  93
  94 u_int8_t* encrypted_packet_get_payload(encrypted_packet_t* packet)
  95 {
  96   if(!packet || !packet->payload_length_)
  97     return NULL;
  98
  99   return (packet->data_.buf_ + sizeof(encrypted_packet_header_t));
 100 }
 101
 102 u_int32_t encrypted_packet_get_payload_length(encrypted_packet_t* packet)
 103 {
 104   if(!packet)
 105     return 0;
 106
 107   return packet->payload_length_;
 108 }
 109
 110 void encrypted_packet_set_payload_length(encrypted_packet_t* packet, u_int32_t len)
 111 {
 112   if(!packet)
 113     return;
 114
 115   if(len > (ENCRYPTED_PACKET_SIZE_MAX - sizeof(encrypted_packet_header_t) - packet->auth_tag_length_))
 116     len = ENCRYPTED_PACKET_SIZE_MAX - sizeof(encrypted_packet_header_t) - packet->auth_tag_length_;
 117
 118   packet->payload_length_ = len;
 119 }
 120
 121 u_int8_t* encrypted_packet_get_auth_portion(encrypted_packet_t* packet)
 122 {
 123   if(!packet)
 124     return NULL;
 125
 126   return packet->data_.buf_;
 127 }
 128
 129 u_int32_t encrypted_packet_get_auth_portion_length(encrypted_packet_t* packet)
 130 {
 131   if(!packet)
 132     return 0;
 133
 134   return  packet->payload_length_ + sizeof(encrypted_packet_header_t);
 135 }
 136
 137
 138 u_int8_t* encrypted_packet_get_auth_tag(encrypted_packet_t* packet)
 139 {
 140   if(!packet || !packet->auth_tag_length_)
 141     return NULL;
 142
 143   return (packet->data_.buf_ + sizeof(encrypted_packet_header_t) + packet->payload_length_);
 144 }
 145
 146 u_int32_t encrypted_packet_get_auth_tag_length(encrypted_packet_t* packet)
 147 {
 148   if(!packet)
 149     return 0;
 150
 151   return packet->auth_tag_length_;
 152 }
 153
 154
 155 seq_nr_t encrypted_packet_get_seq_nr(encrypted_packet_t* packet)
 156 {
 157   if(!packet)
 158     return 0;
 159
 160   return SEQ_NR_T_NTOH(packet->data_.header_.seq_nr_);
 161 }
 162
 163 void encrypted_packet_set_seq_nr(encrypted_packet_t* packet, seq_nr_t seq_nr)
 164 {
 165   if(!packet)
 166     return;
 167
 168   packet->data_.header_.seq_nr_ = SEQ_NR_T_HTON(seq_nr);
 169 }
 170
 171 sender_id_t encrypted_packet_get_sender_id(encrypted_packet_t* packet)
 172 {
 173   if(!packet)
 174     return 0;
 175
 176   return SENDER_ID_T_NTOH(packet->data_.header_.sender_id_);
 177 }
 178
 179 void encrypted_packet_set_sender_id(encrypted_packet_t* packet, sender_id_t sender_id)
 180 {
 181   if(!packet)
 182     return;
 183
 184   packet->data_.header_.sender_id_ = SENDER_ID_T_HTON(sender_id);
 185 }
 186
 187 mux_t encrypted_packet_get_mux(encrypted_packet_t* packet)
 188 {
 189   if(!packet)
 190     return 0;
 191
 192   return MUX_T_NTOH(packet->data_.header_.mux_);
 193 }
 194
 195 void encrypted_packet_set_mux(encrypted_packet_t* packet, mux_t mux)
 196 {
 197   if(!packet)
 198     return;
 199
 200   packet->data_.header_.mux_ = MUX_T_HTON(mux);
 201 }