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 GNUNET_PACKED;
  60
  61   /**
  62    * Here we get an ETH_P_-number.
  63    */
  64   uint16_t proto GNUNET_PACKED;
  65 };
  66
  67
  68 /**
  69  * Standard IPv4 header.
  70  */
  71 struct GNUNET_TUN_IPv4Header
  72 {
  73 #if __BYTE_ORDER == __LITTLE_ENDIAN
  74   unsigned int header_length:4 GNUNET_PACKED;
  75   unsigned int version:4 GNUNET_PACKED;
  76 #elif __BYTE_ORDER == __BIG_ENDIAN
  77   unsigned int version:4 GNUNET_PACKED;
  78   unsigned int header_length:4 GNUNET_PACKED;
  79 #endif
  80   uint8_t diff_serv;
  81
  82   /**
  83    * Length of the packet, including this header.
  84    */
  85   uint16_t total_length GNUNET_PACKED;
  86
  87   /**
  88    * Unique random ID for matching up fragments.
  89    */
  90   uint16_t identification GNUNET_PACKED;
  91
  92   unsigned int flags:3 GNUNET_PACKED;
  93
  94   unsigned int fragmentation_offset:13 GNUNET_PACKED;
  95
  96   /**
  97    * How many more hops can this packet be forwarded?
  98    */
  99   uint8_t ttl;
 100
 101   /**
 102    * L4-protocol, for example, IPPROTO_UDP or IPPROTO_TCP.
 103    */
 104   uint8_t protocol;
 105
 106   /**
 107    * Checksum.
 108    */
 109   uint16_t checksum GNUNET_PACKED;
 110
 111   /**
 112    * Origin of the packet.
 113    */
 114   struct in_addr source_address GNUNET_PACKED;
 115
 116   /**
 117    * Destination of the packet.
 118    */
 119   struct in_addr destination_address GNUNET_PACKED;
 120 };
 121
 122
 123 /**
 124  * Standard IPv6 header.
 125  */
 126 struct GNUNET_TUN_IPv6Header
 127 {
 128 #if __BYTE_ORDER == __LITTLE_ENDIAN
 129   unsigned int traffic_class_h:4 GNUNET_PACKED;
 130   unsigned int version:4 GNUNET_PACKED;
 131   unsigned int traffic_class_l:4 GNUNET_PACKED;
 132   unsigned int flow_label:20 GNUNET_PACKED;
 133 #elif __BYTE_ORDER == __BIG_ENDIAN
 134   unsigned int version:4 GNUNET_PACKED;
 135   unsigned int traffic_class_h:4 GNUNET_PACKED;
 136   unsigned int traffic_class_l:4 GNUNET_PACKED;
 137   unsigned int flow_label:20 GNUNET_PACKED;
 138 #endif
 139   /**
 140    * Length of the payload, excluding this header.
 141    */
 142   uint16_t payload_length GNUNET_PACKED;
 143
 144   /**
 145    * For example, IPPROTO_UDP or IPPROTO_TCP.
 146    */
 147   uint8_t next_header;
 148
 149   /**
 150    * How many more hops can this packet be forwarded?
 151    */
 152   uint8_t hop_limit;
 153
 154   /**
 155    * Origin of the packet.
 156    */
 157   struct in6_addr source_address GNUNET_PACKED;
 158
 159   /**
 160    * Destination of the packet.
 161    */
 162   struct in6_addr destination_address GNUNET_PACKED;
 163 };
 164
 165
 166 /**
 167  * TCP packet header.
 168  */
 169 struct GNUNET_TUN_TcpHeader
 170 {
 171   uint16_t source_port GNUNET_PACKED;
 172   uint16_t destination_port GNUNET_PACKED;
 173
 174   /**
 175    * Sequence number.
 176    */
 177   uint32_t seq GNUNET_PACKED;
 178
 179   /**
 180    * Acknowledgement number.
 181    */
 182   uint32_t ack GNUNET_PACKED;
 183 #if __BYTE_ORDER == __LITTLE_ENDIAN
 184   /**
 185    * Reserved.
 186    */
 187   unsigned int reserved : 4 GNUNET_PACKED;
 188   /**
 189    * Number of 32-bit words in TCP header.
 190    */
 191   unsigned int off : 4 GNUNET_PACKED;
 192 #elif __BYTE_ORDER == __BIG_ENDIAN
 193   /**
 194    * Number of 32-bit words in TCP header.
 195    */
 196   unsigned int off : 4 GNUNET_PACKED;
 197   /**
 198    * Reserved.
 199    */
 200   unsigned int reserved : 4 GNUNET_PACKED;
 201 #endif
 202   uint8_t flags;
 203
 204   /**
 205    * Window size.
 206    */
 207   uint16_t window_size GNUNET_PACKED;
 208
 209   /**
 210    * Checksum.
 211    */
 212   uint16_t crc GNUNET_PACKED;
 213
 214   /**
 215    * Urgent pointer.
 216    */
 217   uint16_t urgent_pointer GNUNET_PACKED;
 218 };
 219
 220
 221 /**
 222  * UDP packet header.
 223  */
 224 struct GNUNET_TUN_UdpHeader
 225 {
 226   uint16_t source_port GNUNET_PACKED;
 227   uint16_t destination_port GNUNET_PACKED;
 228   uint16_t len GNUNET_PACKED;
 229   uint16_t crc GNUNET_PACKED;
 230 };
 231
 232
 233 /**
 234  * DNS header.
 235  */
 236 struct GNUNET_TUN_DnsHeader
 237 {
 238   uint16_t id GNUNET_PACKED;
 239   uint16_t flags GNUNET_PACKED;
 240   uint16_t qdcount GNUNET_PACKED;
 241   uint16_t ancount GNUNET_PACKED;
 242   uint16_t nscount GNUNET_PACKED;
 243   uint16_t arcount GNUNET_PACKED;
 244 };
 245
 246 #define GNUNET_TUN_ICMPTYPE_ECHO_REPLY 0
 247 #define GNUNET_TUN_ICMPTYPE_DESTINATION_UNREACHABLE 3
 248 #define GNUNET_TUN_ICMPTYPE_SOURCE_QUENCH 4
 249 #define GNUNET_TUN_ICMPTYPE_REDIRECT_MESSAGE 5
 250 #define GNUNET_TUN_ICMPTYPE_ECHO_REQUEST 8
 251 #define GNUNET_TUN_ICMPTYPE_ROUTER_ADVERTISEMENT 9
 252 #define GNUNET_TUN_ICMPTYPE_ROUTER_SOLICITATION 10
 253 #define GNUNET_TUN_ICMPTYPE_TIME_EXCEEDED 11
 254
 255 #define GNUNET_TUN_ICMPTYPE6_DESTINATION_UNREACHABLE 1
 256 #define GNUNET_TUN_ICMPTYPE6_PACKET_TOO_BIG 2
 257 #define GNUNET_TUN_ICMPTYPE6_TIME_EXCEEDED 3
 258 #define GNUNET_TUN_ICMPTYPE6_PARAMETER_PROBLEM 4
 259 #define GNUNET_TUN_ICMPTYPE6_ECHO_REQUEST 128
 260 #define GNUNET_TUN_ICMPTYPE6_ECHO_REPLY 129
 261
 262
 263 /**
 264  * ICMP header.
 265  */
 266 struct GNUNET_TUN_IcmpHeader {
 267   uint8_t type;
 268   uint8_t code;
 269   uint16_t crc GNUNET_PACKED;
 270
 271   union {
 272     /**
 273      * ICMP Echo (request/reply)
 274      */
 275     struct {
 276       uint16_t  identifier GNUNET_PACKED;
 277       uint16_t  sequence_number GNUNET_PACKED;
 278     } echo;
 279
 280     /**
 281      * ICMP Destination Unreachable (RFC 1191)
 282      */
 283     struct ih_pmtu {
 284       uint16_t empty GNUNET_PACKED;
 285       uint16_t next_hop_mtu GNUNET_PACKED;
 286       /* followed by original IP header + first 8 bytes of original IP datagram */
 287     } destination_unreachable;
 288
 289     /**
 290      * ICMP Redirect
 291      */
 292     struct in_addr redirect_gateway_address GNUNET_PACKED;
 293
 294     /**
 295      * MTU for packets that are too big (IPv6).
 296      */
 297     uint32_t packet_too_big_mtu GNUNET_PACKED;
 298
 299   } quench;
 300
 301 };
 302
 303
 304 GNUNET_NETWORK_STRUCT_END
 305
 306
 307 /**
 308  * Initialize an IPv4 header.
 309  *
 310  * @param ip header to initialize
 311  * @param protocol protocol to use (i.e. IPPROTO_UDP)
 312  * @param payload_length number of bytes of payload that follow (excluding IPv4 header)
 313  * @param src source IP address to use
 314  * @param dst destination IP address to use
 315  */
 316 void
 317 GNUNET_TUN_initialize_ipv4_header (struct GNUNET_TUN_IPv4Header *ip,
 318                                    uint8_t protocol,
 319                                    uint16_t payload_length,
 320                                    const struct in_addr *src,
 321                                    const struct in_addr *dst);
 322
 323
 324 /**
 325  * Initialize an IPv6 header.
 326  *
 327  * @param ip header to initialize
 328  * @param protocol protocol to use (i.e. IPPROTO_UDP)
 329  * @param payload_length number of bytes of payload that follow (excluding IPv4 header)
 330  * @param src source IP address to use
 331  * @param dst destination IP address to use
 332  */
 333 void
 334 GNUNET_TUN_initialize_ipv6_header (struct GNUNET_TUN_IPv6Header *ip,
 335                                    uint8_t protocol,
 336                                    uint16_t payload_length,
 337                                    const struct in6_addr *src,
 338                                    const struct in6_addr *dst);
 339
 340 /**
 341  * Calculate IPv4 TCP checksum.
 342  *
 343  * @param ip ipv4 header fully initialized
 344  * @param tcp TCP header (initialized except for CRC)
 345  * @param payload the TCP payload
 346  * @param payload_length number of bytes of TCP payload
 347  */
 348 void
 349 GNUNET_TUN_calculate_tcp4_checksum (const struct GNUNET_TUN_IPv4Header *ip,
 350                                     struct GNUNET_TUN_TcpHeader *tcp,
 351                                     const void *payload,
 352                                     uint16_t payload_length);
 353
 354 /**
 355  * Calculate IPv6 TCP checksum.
 356  *
 357  * @param ip ipv6 header fully initialized
 358  * @param tcp TCP header (initialized except for CRC)
 359  * @param payload the TCP payload
 360  * @param payload_length number of bytes of TCP payload
 361  */
 362 void
 363 GNUNET_TUN_calculate_tcp6_checksum (const struct GNUNET_TUN_IPv6Header *ip,
 364                                     struct GNUNET_TUN_TcpHeader *tcp,
 365                                     const void *payload,
 366                                     uint16_t payload_length);
 367
 368 /**
 369  * Calculate IPv4 UDP checksum.
 370  *
 371  * @param ip ipv4 header fully initialized
 372  * @param udp UDP header (initialized except for CRC)
 373  * @param payload the UDP payload
 374  * @param payload_length number of bytes of UDP payload
 375  */
 376 void
 377 GNUNET_TUN_calculate_udp4_checksum (const struct GNUNET_TUN_IPv4Header *ip,
 378                                     struct GNUNET_TUN_UdpHeader *udp,
 379                                     const void *payload,
 380                                     uint16_t payload_length);
 381
 382
 383 /**
 384  * Calculate IPv6 UDP checksum.
 385  *
 386  * @param ip ipv6 header fully initialized
 387  * @param udp UDP header (initialized except for CRC)
 388  * @param payload the UDP payload
 389  * @param payload_length number of bytes of UDP payload
 390  */
 391 void
 392 GNUNET_TUN_calculate_udp6_checksum (const struct GNUNET_TUN_IPv6Header *ip,
 393                                     struct GNUNET_TUN_UdpHeader *udp,
 394                                     const void *payload,
 395                                     uint16_t payload_length);
 396
 397
 398 /**
 399  * Calculate ICMP checksum.
 400  *
 401  * @param icmp IMCP header (initialized except for CRC)
 402  * @param payload the ICMP payload
 403  * @param payload_length number of bytes of ICMP payload
 404  */
 405 void
 406 GNUNET_TUN_calculate_icmp_checksum (struct GNUNET_TUN_IcmpHeader *icmp,
 407                                     const void *payload,
 408                                     uint16_t payload_length);
 409
 410
 411 #endif