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 methods 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) 2007-2014 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  *  In addition, as a special exception, the copyright holders give
  36  *  permission to link the code of portions of this program with the
  37  *  OpenSSL library under certain conditions as described in each
  38  *  individual source file, and distribute linked combinations
  39  *  including the two.
  40  *  You must obey the GNU General Public License in all respects
  41  *  for all of the code used other than OpenSSL.  If you modify
  42  *  file(s) with this exception, you may extend this exception to your
  43  *  version of the file(s), but you are not obligated to do so.  If you
  44  *  do not wish to do so, delete this exception statement from your
  45  *  version.  If you delete this exception statement from all source
  46  *  files in the program, then also delete it here.
  47  */
  48
  49 #include "datatypes.h"
  50
  51 #include "encrypted_packet.h"
  52
  53 #include <stdlib.h>
  54 #include <string.h>
  55
  56 void encrypted_packet_init(encrypted_packet_t* packet, u_int32_t auth_tag_length)
  57 {
  58   if(!packet)
  59     return;
  60
  61   memset (packet, 0, sizeof(*packet));
  62   if(auth_tag_length > (ENCRYPTED_PACKET_SIZE_MAX - sizeof(encrypted_packet_header_t)))
  63     packet->auth_tag_length_ = ENCRYPTED_PACKET_SIZE_MAX - sizeof(encrypted_packet_header_t);
  64   else
  65     packet->auth_tag_length_ = auth_tag_length;
  66 }
  67
  68 u_int32_t encrypted_packet_get_minimum_length(encrypted_packet_t* packet)
  69 {
  70   if(!packet)
  71     return 0;
  72
  73   return (sizeof(encrypted_packet_header_t) + packet->auth_tag_length_);
  74 }
  75
  76 u_int8_t* encrypted_packet_get_packet(encrypted_packet_t* packet)
  77 {
  78   if(!packet)
  79     return NULL;
  80
  81   return packet->data_.buf_;
  82 }
  83
  84 u_int32_t encrypted_packet_get_length(encrypted_packet_t* packet)
  85 {
  86   if(!packet)
  87     return 0;
  88
  89   return (packet->payload_length_ + sizeof(encrypted_packet_header_t) + packet->auth_tag_length_);
  90 }
  91
  92 void encrypted_packet_set_length(encrypted_packet_t* packet, u_int32_t len)
  93 {
  94   if(!packet)
  95     return;
  96
  97   if(len > ENCRYPTED_PACKET_SIZE_MAX)
  98     len = ENCRYPTED_PACKET_SIZE_MAX - sizeof(encrypted_packet_header_t) - packet->auth_tag_length_;
  99   else if(len < (sizeof(encrypted_packet_header_t) + packet->auth_tag_length_))
 100     len = 0;
 101   else
 102     len -= (sizeof(encrypted_packet_header_t) + packet->auth_tag_length_);
 103
 104   packet->payload_length_ = len;
 105 }
 106
 107 u_int8_t* encrypted_packet_get_payload(encrypted_packet_t* packet)
 108 {
 109   if(!packet || !packet->payload_length_)
 110     return NULL;
 111
 112   return (packet->data_.buf_ + sizeof(encrypted_packet_header_t));
 113 }
 114
 115 u_int32_t encrypted_packet_get_payload_length(encrypted_packet_t* packet)
 116 {
 117   if(!packet)
 118     return 0;
 119
 120   return packet->payload_length_;
 121 }
 122
 123 void encrypted_packet_set_payload_length(encrypted_packet_t* packet, u_int32_t len)
 124 {
 125   if(!packet)
 126     return;
 127
 128   if(len > (ENCRYPTED_PACKET_SIZE_MAX - sizeof(encrypted_packet_header_t) - packet->auth_tag_length_))
 129     len = ENCRYPTED_PACKET_SIZE_MAX - sizeof(encrypted_packet_header_t) - packet->auth_tag_length_;
 130
 131   packet->payload_length_ = len;
 132 }
 133
 134 u_int8_t* encrypted_packet_get_auth_portion(encrypted_packet_t* packet)
 135 {
 136   if(!packet)
 137     return NULL;
 138
 139   return packet->data_.buf_;
 140 }
 141
 142 u_int32_t encrypted_packet_get_auth_portion_length(encrypted_packet_t* packet)
 143 {
 144   if(!packet)
 145     return 0;
 146
 147   return  packet->payload_length_ + sizeof(encrypted_packet_header_t);
 148 }
 149
 150
 151 u_int8_t* encrypted_packet_get_auth_tag(encrypted_packet_t* packet)
 152 {
 153   if(!packet || !packet->auth_tag_length_)
 154     return NULL;
 155
 156   return (packet->data_.buf_ + sizeof(encrypted_packet_header_t) + packet->payload_length_);
 157 }
 158
 159 u_int32_t encrypted_packet_get_auth_tag_length(encrypted_packet_t* packet)
 160 {
 161   if(!packet)
 162     return 0;
 163
 164   return packet->auth_tag_length_;
 165 }
 166
 167
 168 seq_nr_t encrypted_packet_get_seq_nr(encrypted_packet_t* packet)
 169 {
 170   if(!packet)
 171     return 0;
 172
 173   return SEQ_NR_T_NTOH(packet->data_.header_.seq_nr_);
 174 }
 175
 176 void encrypted_packet_set_seq_nr(encrypted_packet_t* packet, seq_nr_t seq_nr)
 177 {
 178   if(!packet)
 179     return;
 180
 181   packet->data_.header_.seq_nr_ = SEQ_NR_T_HTON(seq_nr);
 182 }
 183
 184 sender_id_t encrypted_packet_get_sender_id(encrypted_packet_t* packet)
 185 {
 186   if(!packet)
 187     return 0;
 188
 189   return SENDER_ID_T_NTOH(packet->data_.header_.sender_id_);
 190 }
 191
 192 void encrypted_packet_set_sender_id(encrypted_packet_t* packet, sender_id_t sender_id)
 193 {
 194   if(!packet)
 195     return;
 196
 197   packet->data_.header_.sender_id_ = SENDER_ID_T_HTON(sender_id);
 198 }
 199
 200 mux_t encrypted_packet_get_mux(encrypted_packet_t* packet)
 201 {
 202   if(!packet)
 203     return 0;
 204
 205   return MUX_T_NTOH(packet->data_.header_.mux_);
 206 }
 207
 208 void encrypted_packet_set_mux(encrypted_packet_t* packet, mux_t mux)
 209 {
 210   if(!packet)
 211     return;
 212
 213   packet->data_.header_.mux_ = MUX_T_HTON(mux);
 214 }