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