src/include/gnunet_tun_lib.h

   1 /*
   2      This file is part of GNUnet.
   3      (C) 2010, 2011, 2012 Christian Grothoff
   4
   5      GNUnet is free software; you can redistribute it and/or modify
   6      it under the terms of the GNU General Public License as published
   7      by the Free Software Foundation; either version 3, or (at your
   8      option) any later version.
   9
  10      GNUnet is distributed in the hope that it will be useful, but
  11      WITHOUT ANY WARRANTY; without even the implied warranty of
  12      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13      General Public License for more details.
  14
  15      You should have received a copy of the GNU General Public License
  16      along with GNUnet; see the file COPYING.  If not, write to the
  17      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18      Boston, MA 02111-1307, USA.
  19 */
  20
  21 /**
  22  * @file include/gnunet_tun_lib.h
  23  * @brief standard TCP/IP network structs and IP checksum calculations for TUN interaction
  24  * @author Philipp Toelke
  25  * @author Christian Grothoff
  26  */
  27 #ifndef GNUNET_TUN_LIB_H
  28 #define GNUNET_TUN_LIB_H
  29
  30 #include "gnunet_util_lib.h"
  31
  32
  33 /* see http://www.iana.org/assignments/ethernet-numbers */
  34 #ifndef ETH_P_IPV4
  35 /**
  36  * Number for IPv4
  37  */
  38 #define ETH_P_IPV4 0x0800
  39 #endif
  40
  41 #ifndef ETH_P_IPV6
  42 /**
  43  * Number for IPv6
  44  */
  45 #define ETH_P_IPV6 0x86DD
  46 #endif
  47
  48
  49 GNUNET_NETWORK_STRUCT_BEGIN
  50
  51 /**
  52  * Header from Linux TUN interface.
  53  */
  54 struct GNUNET_TUN_Layer2PacketHeader
  55 {
  56   /**
  57    * Some flags (unused).
  58    */
  59   uint16_t flags;
  60
  61   /**
  62    * Here we get an ETH_P_-number.
  63    */
  64   uint16_t proto;
  65 };
  66
  67
  68 /**
  69  * Standard IPv4 header.
  70  */
  71 struct GNUNET_TUN_IPv4Header
  72 {
  73   unsigned header_length:4 GNUNET_PACKED;
  74   unsigned version:4 GNUNET_PACKED;
  75   uint8_t diff_serv;
  76   uint16_t total_length GNUNET_PACKED;
  77   uint16_t identification GNUNET_PACKED;
  78   unsigned flags:3 GNUNET_PACKED;
  79   unsigned fragmentation_offset:13 GNUNET_PACKED;
  80   uint8_t ttl;
  81   uint8_t protocol;
  82   uint16_t checksum GNUNET_PACKED;
  83   struct in_addr source_address GNUNET_PACKED;
  84   struct in_addr destination_address GNUNET_PACKED;
  85 };
  86
  87
  88 /**
  89  * Standard IPv6 header.
  90  */
  91 struct GNUNET_TUN_IPv6Header
  92 {
  93   unsigned traffic_class_h:4 GNUNET_PACKED;
  94   unsigned version:4 GNUNET_PACKED;
  95   unsigned traffic_class_l:4 GNUNET_PACKED;
  96   unsigned flow_label:20 GNUNET_PACKED;
  97   uint16_t payload_length GNUNET_PACKED;
  98   uint8_t next_header;
  99   uint8_t hop_limit;
 100   struct in6_addr source_address GNUNET_PACKED;
 101   struct in6_addr destination_address GNUNET_PACKED;
 102 };
 103
 104
 105 /**
 106  * TCP packet header (FIXME: rename!)
 107  */
 108 struct GNUNET_TUN_TcpHeader
 109 {
 110   unsigned spt:16 GNUNET_PACKED;
 111   unsigned dpt:16 GNUNET_PACKED;
 112   unsigned seq:32 GNUNET_PACKED;
 113   unsigned ack:32 GNUNET_PACKED;
 114   unsigned off:4 GNUNET_PACKED;
 115   unsigned rsv:4 GNUNET_PACKED;
 116   unsigned flg:8 GNUNET_PACKED;
 117   unsigned wsz:16 GNUNET_PACKED;
 118   unsigned crc:16 GNUNET_PACKED;
 119   unsigned urg:16 GNUNET_PACKED;
 120 };
 121
 122
 123 /**
 124  * UDP packet header  (FIXME: rename!)
 125  */
 126 struct GNUNET_TUN_UdpHeader
 127 {
 128   uint16_t spt GNUNET_PACKED;
 129   uint16_t dpt GNUNET_PACKED;
 130   uint16_t len GNUNET_PACKED;
 131   uint16_t crc GNUNET_PACKED;
 132 };
 133
 134
 135 /**
 136  * DNS header.
 137  */
 138 struct GNUNET_TUN_DnsHeader
 139 {
 140   uint16_t id GNUNET_PACKED;
 141   uint16_t flags GNUNET_PACKED;
 142   uint16_t qdcount GNUNET_PACKED;
 143   uint16_t ancount GNUNET_PACKED;
 144   uint16_t nscount GNUNET_PACKED;
 145   uint16_t arcount GNUNET_PACKED;
 146 };
 147
 148 GNUNET_NETWORK_STRUCT_END
 149
 150
 151 /**
 152  * Initialize an IPv4 header.
 153  *
 154  * @param ip header to initialize
 155  * @param protocol protocol to use (i.e. IPPROTO_UDP)
 156  * @param payload_length number of bytes of payload that follow (excluding IPv4 header)
 157  * @param src source IP address to use
 158  * @param dst destination IP address to use
 159  */
 160 void
 161 GNUNET_TUN_initialize_ipv4_header (struct GNUNET_TUN_IPv4Header *ip,
 162                                    uint8_t protocol,
 163                                    uint16_t payload_length,
 164                                    const struct in_addr *src,
 165                                    const struct in_addr *dst);
 166
 167
 168 /**
 169  * Initialize an IPv6 header.
 170  *
 171  * @param ip header to initialize
 172  * @param protocol protocol to use (i.e. IPPROTO_UDP)
 173  * @param payload_length number of bytes of payload that follow (excluding IPv4 header)
 174  * @param src source IP address to use
 175  * @param dst destination IP address to use
 176  */
 177 void
 178 GNUNET_TUN_initialize_ipv6_header (struct GNUNET_TUN_IPv6Header *ip,
 179                                    uint8_t protocol,
 180                                    uint16_t payload_length,
 181                                    const struct in6_addr *src,
 182                                    const struct in6_addr *dst);
 183
 184 /**
 185  * Calculate IPv6 TCP checksum.
 186  *
 187  * @param ipv6 header fully initialized
 188  * @param tcp header (initialized except for CRC)
 189  * @param payload the TCP payload
 190  * @param payload_length number of bytes of TCP payload
 191  */
 192 void
 193 GNUNET_TUN_calculate_tcp6_checksum (const struct GNUNET_TUN_IPv6Header *ip,
 194                                     struct GNUNET_TUN_TcpHeader *tcp,
 195                                     const void *payload,
 196                                     uint16_t payload_length);
 197
 198
 199 #endif