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   /**
 115    * Reserved.
 116    */
 117   unsigned rsv:4 GNUNET_PACKED;
 118   /**
 119    * Number of 32-bit words in TCP header.
 120    */
 121   unsigned off:4 GNUNET_PACKED;
 122   unsigned flg:8 GNUNET_PACKED;
 123   /**
 124    * Window size.
 125    */
 126   unsigned wsz:16 GNUNET_PACKED;
 127   unsigned crc:16 GNUNET_PACKED;
 128   /**
 129    * Urgent pointer.
 130    */
 131   unsigned urg:16 GNUNET_PACKED;
 132 };
 133
 134
 135 /**
 136  * UDP packet header  (FIXME: rename!)
 137  */
 138 struct GNUNET_TUN_UdpHeader
 139 {
 140   uint16_t spt GNUNET_PACKED;
 141   uint16_t dpt GNUNET_PACKED;
 142   uint16_t len GNUNET_PACKED;
 143   uint16_t crc GNUNET_PACKED;
 144 };
 145
 146
 147 /**
 148  * DNS header.
 149  */
 150 struct GNUNET_TUN_DnsHeader
 151 {
 152   uint16_t id GNUNET_PACKED;
 153   uint16_t flags GNUNET_PACKED;
 154   uint16_t qdcount GNUNET_PACKED;
 155   uint16_t ancount GNUNET_PACKED;
 156   uint16_t nscount GNUNET_PACKED;
 157   uint16_t arcount GNUNET_PACKED;
 158 };
 159
 160 #define GNUNET_TUN_ICMPTYPE_ECHO_REPLY 0
 161 #define GNUNET_TUN_ICMPTYPE_DESTINATION_UNREACHABLE 3
 162 #define GNUNET_TUN_ICMPTYPE_SOURCE_QUENCH 4
 163 #define GNUNET_TUN_ICMPTYPE_REDIRECT_MESSAGE 5
 164 #define GNUNET_TUN_ICMPTYPE_ECHO_REQUEST 8
 165 #define GNUNET_TUN_ICMPTYPE_ROUTER_ADVERTISEMENT 9
 166 #define GNUNET_TUN_ICMPTYPE_ROUTER_SOLICITATION 10
 167 #define GNUNET_TUN_ICMPTYPE_TIME_EXCEEDED 11
 168
 169 #define GNUNET_TUN_ICMPTYPE6_DESTINATION_UNREACHABLE 1
 170 #define GNUNET_TUN_ICMPTYPE6_PACKET_TOO_BIG 2
 171 #define GNUNET_TUN_ICMPTYPE6_TIME_EXCEEDED 3
 172 #define GNUNET_TUN_ICMPTYPE6_PARAMETER_PROBLEM 4
 173 #define GNUNET_TUN_ICMPTYPE6_ECHO_REQUEST 128
 174 #define GNUNET_TUN_ICMPTYPE6_ECHO_REPLY 129
 175
 176 /**
 177  * ICMP header.
 178  */
 179 struct GNUNET_TUN_IcmpHeader {
 180   uint8_t type;
 181   uint8_t code;
 182   uint16_t crc;
 183
 184   union {
 185     /**
 186      * ICMP Echo (request/reply)
 187      */
 188     struct {
 189       uint16_t  identifier;
 190       uint16_t  sequence_number;
 191     } echo;
 192
 193     /**
 194      * ICMP Destination Unreachable (RFC 1191)
 195      */
 196     struct ih_pmtu {
 197       uint16_t empty;
 198       uint16_t next_hop_mtu;
 199       /* followed by original IP header + first 8 bytes of original IP datagram */
 200     } destination_unreachable;
 201
 202     /**
 203      * ICMP Redirect
 204      */
 205     struct in_addr redirect_gateway_address;
 206
 207     /**
 208      * MTU for packets that are too big (IPv6).
 209      */
 210     uint32_t packet_too_big_mtu;
 211
 212   } quench;
 213
 214 };
 215
 216
 217 GNUNET_NETWORK_STRUCT_END
 218
 219
 220 /**
 221  * Initialize an IPv4 header.
 222  *
 223  * @param ip header to initialize
 224  * @param protocol protocol to use (i.e. IPPROTO_UDP)
 225  * @param payload_length number of bytes of payload that follow (excluding IPv4 header)
 226  * @param src source IP address to use
 227  * @param dst destination IP address to use
 228  */
 229 void
 230 GNUNET_TUN_initialize_ipv4_header (struct GNUNET_TUN_IPv4Header *ip,
 231                                    uint8_t protocol,
 232                                    uint16_t payload_length,
 233                                    const struct in_addr *src,
 234                                    const struct in_addr *dst);
 235
 236
 237 /**
 238  * Initialize an IPv6 header.
 239  *
 240  * @param ip header to initialize
 241  * @param protocol protocol to use (i.e. IPPROTO_UDP)
 242  * @param payload_length number of bytes of payload that follow (excluding IPv4 header)
 243  * @param src source IP address to use
 244  * @param dst destination IP address to use
 245  */
 246 void
 247 GNUNET_TUN_initialize_ipv6_header (struct GNUNET_TUN_IPv6Header *ip,
 248                                    uint8_t protocol,
 249                                    uint16_t payload_length,
 250                                    const struct in6_addr *src,
 251                                    const struct in6_addr *dst);
 252
 253 /**
 254  * Calculate IPv4 TCP checksum.
 255  *
 256  * @param ip ipv4 header fully initialized
 257  * @param tcp TCP header (initialized except for CRC)
 258  * @param payload the TCP payload
 259  * @param payload_length number of bytes of TCP payload
 260  */
 261 void
 262 GNUNET_TUN_calculate_tcp4_checksum (const struct GNUNET_TUN_IPv4Header *ip,
 263                                     struct GNUNET_TUN_TcpHeader *tcp,
 264                                     const void *payload,
 265                                     uint16_t payload_length);
 266
 267 /**
 268  * Calculate IPv6 TCP checksum.
 269  *
 270  * @param ip ipv6 header fully initialized
 271  * @param tcp TCP header (initialized except for CRC)
 272  * @param payload the TCP payload
 273  * @param payload_length number of bytes of TCP payload
 274  */
 275 void
 276 GNUNET_TUN_calculate_tcp6_checksum (const struct GNUNET_TUN_IPv6Header *ip,
 277                                     struct GNUNET_TUN_TcpHeader *tcp,
 278                                     const void *payload,
 279                                     uint16_t payload_length);
 280
 281 /**
 282  * Calculate IPv4 UDP checksum.
 283  *
 284  * @param ip ipv4 header fully initialized
 285  * @param udp UDP header (initialized except for CRC)
 286  * @param payload the UDP payload
 287  * @param payload_length number of bytes of UDP payload
 288  */
 289 void
 290 GNUNET_TUN_calculate_udp4_checksum (const struct GNUNET_TUN_IPv4Header *ip,
 291                                     struct GNUNET_TUN_UdpHeader *udp,
 292                                     const void *payload,
 293                                     uint16_t payload_length);
 294
 295
 296 /**
 297  * Calculate IPv6 UDP checksum.
 298  *
 299  * @param ip ipv6 header fully initialized
 300  * @param udp UDP header (initialized except for CRC)
 301  * @param payload the UDP payload
 302  * @param payload_length number of bytes of UDP payload
 303  */
 304 void
 305 GNUNET_TUN_calculate_udp6_checksum (const struct GNUNET_TUN_IPv6Header *ip,
 306                                     struct GNUNET_TUN_UdpHeader *udp,
 307                                     const void *payload,
 308                                     uint16_t payload_length);
 309
 310
 311 /**
 312  * Calculate ICMP checksum.
 313  *
 314  * @param icmp IMCP header (initialized except for CRC)
 315  * @param payload the ICMP payload
 316  * @param payload_length number of bytes of ICMP payload
 317  */
 318 void
 319 GNUNET_TUN_calculate_icmp_checksum (struct GNUNET_TUN_IcmpHeader *icmp,
 320                                     const void *payload,
 321                                     uint16_t payload_length);
 322
 323
 324 #endif