mdw@git.distorted.org.uk Git - tripe/blob - tripe.h

   1 /* -*-c-*-
   2  *
   3  * $Id: tripe.h,v 1.3 2001/02/04 01:17:55 mdw Exp $
   4  *
   5  * Main header file for TrIPE
   6  *
   7  * (c) 2001 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Trivial IP Encryption (TrIPE).
  13  *
  14  * TrIPE is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * TrIPE is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with TrIPE; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: tripe.h,v $
  32  * Revision 1.3  2001/02/04 01:17:55  mdw
  33  * Create a configuration header file to tidy up command lines.
  34  *
  35  * Revision 1.2  2001/02/03 22:40:29  mdw
  36  * Put timer information into the entropy pool when packets are received
  37  * and on similar events.  Reseed the generator on the interval timer.
  38  *
  39  * Revision 1.1  2001/02/03 20:26:37  mdw
  40  * Initial checkin.
  41  *
  42  */
  43
  44 #ifndef TRIPE_H
  45 #define TRIPE_H
  46
  47 #ifdef __cplusplus
  48   extern "C" {
  49 #endif
  50
  51 /*----- Header files ------------------------------------------------------*/
  52
  53 #include "config.h"
  54
  55 #include <assert.h>
  56 #include <ctype.h>
  57 #include <errno.h>
  58 #include <signal.h>
  59 #include <stdarg.h>
  60 #include <stddef.h>
  61 #include <stdio.h>
  62 #include <stdlib.h>
  63 #include <string.h>
  64 #include <time.h>
  65
  66 #include <sys/types.h>
  67 #include <sys/time.h>
  68 #include <unistd.h>
  69 #include <fcntl.h>
  70 #include <sys/stat.h>
  71
  72 #include <sys/socket.h>
  73 #include <sys/un.h>
  74 #include <netinet/in.h>
  75 #include <arpa/inet.h>
  76 #include <netdb.h>
  77
  78 #include <pwd.h>
  79 #include <grp.h>
  80
  81 #include <mLib/alloc.h>
  82 #include <mLib/arena.h>
  83 #include <mLib/bres.h>
  84 #include <mLib/dstr.h>
  85 #include <mLib/env.h>
  86 #include <mLib/fdflags.h>
  87 #include <mLib/fwatch.h>
  88 #include <mLib/mdwopt.h>
  89 #include <mLib/quis.h>
  90 #include <mLib/report.h>
  91 #include <mLib/sel.h>
  92 #include <mLib/selbuf.h>
  93 #include <mLib/sig.h>
  94 #include <mLib/str.h>
  95 #include <mLib/sub.h>
  96 #include <mLib/trace.h>
  97
  98 #include <catacomb/gcipher.h>
  99 #include <catacomb/gmac.h>
 100 #include <catacomb/grand.h>
 101 #include <catacomb/key.h>
 102 #include <catacomb/paranoia.h>
 103
 104 #include <catacomb/blowfish.h>
 105 #include <catacomb/blowfish-cbc.h>
 106 #include <catacomb/noise.h>
 107 #include <catacomb/rand.h>
 108 #include <catacomb/rmd160.h>
 109 #include <catacomb/rmd160-hmac.h>
 110
 111 #include <catacomb/mp.h>
 112 #include <catacomb/mpmont.h>
 113 #include <catacomb/mprand.h>
 114 #include <catacomb/dh.h>
 115
 116 #include "util.h"
 117
 118 #undef sun
 119
 120 /*----- Magic numbers -----------------------------------------------------*/
 121
 122 /* --- Tunnel types --- */
 123
 124 #define TUN_NOTDEF 0
 125 #define TUN_UNET 1
 126 #define TUN_BSD 2
 127
 128 /* --- Trace flags --- */
 129
 130 #define T_TUNNEL 1u
 131 #define T_PEER 2u
 132 #define T_PACKET 4u
 133 #define T_ADMIN 8u
 134 #define T_CRYPTO 16u
 135 #define T_KEYSET 32u
 136 #define T_KEYEXCH 64u
 137 #define T_KEYMGMT 128u
 138
 139 #define T_ALL 255u
 140
 141 /* --- Units --- */
 142
 143 #define SEC(n) (n##u)
 144 #define MIN(n) (n##u * 60u)
 145 #define MEG(n) (n##ul * 1024ul * 1024ul)
 146
 147 /* --- Other things --- */
 148
 149 #define PKBUFSZ 65536
 150
 151 /*----- TrIPE protocol ----------------------------------------------------*/
 152
 153 /* --- TrIPE packet format --- *
 154  *
 155  * A packet begins with a single-byte packet type.  The remaining data
 156  * depends on the packet type.
 157  */
 158
 159 #define MSG_PACKET 0u
 160 /* Followed by a 64-bit MAC and an encrypted packet.  The MAC is used as an
 161  * IV for a 64-bit block cipher in CBC-stealing mode.
 162  */
 163
 164 #define MSG_PRECHALLENGE 1u
 165 /* Followed by the challenge only.  Useful for bootstrapping the system.
 166  */
 167
 168 #define MSG_CHALLENGE 2u
 169 /* Followed by a response hash and a large-integer challenge.
 170  */
 171
 172 #define MSG_RESPONSE 3u
 173 /* Followed by a large-integer response.
 174  */
 175
 176 /*----- Data structures ---------------------------------------------------*/
 177
 178 /* --- Buffers --- *
 179  *
 180  * Buffers provide a simple stream-like interface for building and parsing
 181  * packets.
 182  */
 183
 184 typedef struct buf {
 185   octet *base, *p, *limit;              /* Pointers to the buffer */
 186   unsigned f;                           /* Various flags */
 187 } buf;
 188
 189 #define BF_BROKEN 1u                    /* Buffer is broken */
 190
 191 /* --- Socket addresses --- *
 192  *
 193  * A magic union of supported socket addresses.
 194  */
 195
 196 typedef union addr {
 197   struct sockaddr sa;
 198   struct sockaddr_in sin;
 199 } addr;
 200
 201 /* --- A symmetric keyset --- *
 202  *
 203  * A keyset contains a set of symmetric keys for encrypting and decrypting
 204  * packets.  Keysets are stored in a list, sorted in reverse order of
 205  * creation, so that the most recent keyset (the one most likely to be used)
 206  * is first.
 207  *
 208  * Each keyset has a time limit and a data limit.  The keyset is destroyed
 209  * when either it has existed for too long, or it has been used to encrypt
 210  * too much data.  New key exchanges are triggered when keys are close to
 211  * expiry.
 212  */
 213
 214 typedef struct keyset {
 215   struct keyset *next;                  /* Next active keyset in the list */
 216   time_t t_exp;                         /* Expiry time for this keyset */
 217   unsigned long sz_exp;                 /* Data limit for the keyset */
 218 #ifndef NTRACE
 219   unsigned seq;                         /* Sequence number for tracing */
 220 #endif
 221   gcipher *c;                           /* Keyset cipher for encryption */
 222   gmac *m;                              /* Keyset MAC for integrity */
 223 } keyset;
 224
 225 /* --- Key exchange --- *
 226  *
 227  * TrIPE uses the Wrestlers Protocol for its key exchange.  The Wrestlers
 228  * Protocol has a number of desirable features (e.g., perfect forward
 229  * secrecy, and zero-knowledge authentication) which make it attractive for
 230  * use in TrIPE.  The Wrestlers Protocol was designed by Mark Wooding and
 231  * Clive Jones.
 232  */
 233
 234 typedef struct keyexch {
 235   keyset **ks;                          /* Peer's list of keysets */
 236   struct peer *p;                       /* Pointer back to the peer */
 237   unsigned f;                           /* Various useful flags */
 238   sel_timer t;                          /* Timer for next exchange */
 239   dh_pub kpub;                          /* Peer's public key */
 240   mp *my_x, *my_gx, *my_gxy;            /* My half of the exchange */
 241   octet my_h[RMD160_HASHSZ];            /* My challenge hash */
 242   mp *your_gx, *your_gxy;               /* Your half of the exchange */
 243   octet your_h[RMD160_HASHSZ];          /* Your challenge hash */
 244   time_t t_valid;                       /* When this exchange goes bad */
 245   time_t t_qchal, t_qresp;              /* Quiet timers for packet types */
 246   time_t t_newchal;                     /* When to accept a new challenge */
 247 } keyexch;
 248
 249 #define KXF_TIMER 1u                    /* Waiting for a timer to go off */
 250 #define KXF_INIT 2u                     /* Big numbers are initialized */
 251 #define KXF_MYH 4u                      /* My hash has been computed */
 252 #define KXF_YOURH 8u                    /* Your hash has been received */
 253 #define KXF_REPLY 16u                   /* Received your response OK */
 254 #define KXF_DONE 32u                    /* Key exchange completed */
 255
 256 /* --- Tunnel structure --- *
 257  *
 258  * Used to maintain system-specific information about the tunnel interface.
 259  */
 260
 261 typedef struct tunnel {
 262 #if TUN_TYPE == TUN_UNET
 263   sel_file f;                           /* Selector for Usernet device */
 264   struct peer *p;                       /* Pointer to my peer */
 265 #else
 266 #  error "No support for this tunnel type"
 267 #endif
 268 } tunnel;
 269
 270 /* --- Peer structure --- *
 271  *
 272  * The main structure which glues everything else together.
 273  */
 274
 275 typedef struct peer {
 276   struct peer *next, *prev;             /* Links to next and previous */
 277   char *name;                           /* Name of this peer */
 278   tunnel t;                             /* Tunnel for local packets */
 279   keyset *ks;                           /* List head for keysets */
 280   keyexch kx;                           /* Key exchange protocol block */
 281   buf b;                                /* Buffer for sending packets */
 282   addr peer;                            /* Peer socket address */
 283   size_t sasz;                          /* Socket address size */
 284 } peer;
 285
 286 /* --- Admin structure --- */
 287
 288 typedef struct admin {
 289   struct admin *next, *prev;            /* Links to next and previous */
 290   selbuf b;                             /* Line buffer for commands */
 291   int fd;                               /* File descriptor for output */
 292 #ifndef NTRACE
 293   unsigned seq;                         /* Sequence number for tracing */
 294 #endif
 295   char *pname;                          /* Peer name to create */
 296   char *paddr;                          /* Address string to resolve */
 297   bres_client r;                        /* Background resolver task */
 298   sel_timer t;                          /* Timer for resolver */
 299   addr peer;                            /* Address to set */
 300   size_t sasz;                          /* Size of the address */
 301 } admin;
 302
 303 /*----- Global variables --------------------------------------------------*/
 304
 305 extern sel_state sel;                   /* Global I/O event state */
 306 extern dh_priv kpriv;                   /* Our private key */
 307 extern mpmont mg;                       /* Montgomery context for DH group */
 308 extern octet buf_i[PKBUFSZ], buf_o[PKBUFSZ]; /* Big packet buffers */
 309
 310 #ifndef NTRACE
 311 extern const trace_opt tr_opts[];       /* Trace options array */
 312 extern unsigned tr_flags;               /* Trace options flags */
 313 #endif
 314
 315 /*----- Other macros ------------------------------------------------------*/
 316
 317 #define TIMER noise_timer(RAND_GLOBAL)
 318
 319 /*----- Key management ----------------------------------------------------*/
 320
 321 /* --- @km_interval@ --- *
 322  *
 323  * Arguments:   ---
 324  *
 325  * Returns:     Zero if OK, nonzero to force reloading of keys.
 326  *
 327  * Use:         Called on the interval timer to perform various useful jobs.
 328  */
 329
 330 extern int km_interval(void);
 331
 332 /* --- @km_init@ --- *
 333  *
 334  * Arguments:   @const char *kr_priv@ = private keyring file
 335  *              @const char *kr_pub@ = public keyring file
 336  *              @const char *tag@ = tag to load
 337  *
 338  * Returns:     ---
 339  *
 340  * Use:         Initializes, and loads the private key.
 341  */
 342
 343 extern void km_init(const char */*kr_priv*/, const char */*kr_pub*/,
 344                     const char */*tag*/);
 345
 346 /* --- @km_getpubkey@ --- *
 347  *
 348  * Arguments:   @const char *tag@ = public key tag to load
 349  *              @dh_pub *kpub@ = where to put the public key
 350  *
 351  * Returns:     Zero if OK, nonzero if it failed.
 352  *
 353  * Use:         Fetches a public key from the keyring.
 354  */
 355
 356 extern int km_getpubkey(const char */*tag*/, dh_pub */*kpub*/);
 357
 358 /*----- Key exchange ------------------------------------------------------*/
 359
 360 /* --- @kx_start@ --- *
 361  *
 362  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 363  *
 364  * Returns:     ---
 365  *
 366  * Use:         Stimulates a key exchange.  If a key exchage is in progress,
 367  *              a new challenge is sent (unless the quiet timer forbids
 368  *              this); if no exchange is in progress, one is commenced.
 369  */
 370
 371 extern void kx_start(keyexch */*kx*/);
 372
 373 /* --- @kx_prechallenge@ --- *
 374  *
 375  * Arguments:   @keyexch *kx@ = pointer to key exhange context
 376  *              @buf *b@ = pointer to buffer containing the packet
 377  *
 378  * Returns:     ---
 379  *
 380  * Use:         Reads a prechallenge packet from the buffer and handles it.
 381  */
 382
 383 extern void kx_prechallenge(keyexch */*kx*/, buf */*b*/);
 384
 385 /* --- @kx_challenge@ --- *
 386  *
 387  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 388  *              @buf *b@ = a buffer containing the packet to read
 389  *
 390  * Returns:     ---
 391  *
 392  * Use:         Reads a challenge from the buffer and handles it.
 393  */
 394
 395 extern void kx_challenge(keyexch */*kx*/, buf */*b*/);
 396
 397 /* --- @kx_response@ --- *
 398  *
 399  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 400  *              @buf *b@ = a buffer containing the packet to read
 401  *
 402  * Returns:     ---
 403  *
 404  * Use:         Reads a response from the buffer and handles it.
 405  */
 406
 407 extern void kx_response(keyexch */*kx*/, buf */*b*/);
 408
 409 /* --- @kx_free@ --- *
 410  *
 411  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 412  *
 413  * Returns:     ---
 414  *
 415  * Use:         Frees everything in a key exchange context.
 416  */
 417
 418 extern void kx_free(keyexch */*kx*/);
 419
 420 /* --- @kx_newkeys@ --- *
 421  *
 422  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 423  *
 424  * Returns:     ---
 425  *
 426  * Use:         Informs the key exchange module that its keys may have
 427  *              changed.  If fetching the new keys fails, the peer will be
 428  *              destroyed, we log messages and struggle along with the old
 429  *              keys.
 430  */
 431
 432 extern void kx_newkeys(keyexch */*kx*/);
 433
 434 /* --- @kx_init@ --- *
 435  *
 436  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 437  *              @peer *p@ = pointer to peer context
 438  *              @keyset **ks@ = pointer to keyset list
 439  *
 440  * Returns:     Zero if OK, nonzero if it failed.
 441  *
 442  * Use:         Initializes a key exchange module.  The module currently
 443  *              contains no keys, and will attempt to initiate a key
 444  *              exchange.
 445  */
 446
 447 extern int kx_init(keyexch */*kx*/, peer */*p*/, keyset **/*ks*/);
 448
 449 /*----- Keysets and symmetric cryptography --------------------------------*/
 450
 451 /* --- @ks_free@ --- *
 452  *
 453  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 454  *
 455  * Returns:     ---
 456  *
 457  * Use:         Frees all of the keys in a keyset.
 458  */
 459
 460 extern void ks_free(keyset **/*ksroot*/);
 461
 462 /* --- @ks_prune@ --- *
 463  *
 464  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 465  *
 466  * Returns:     ---
 467  *
 468  * Use:         Prunes the keyset list by removing keys which mustn't be used
 469  *              any more.
 470  */
 471
 472 extern void ks_prune(keyset **/*ksroot*/);
 473
 474 /* --- @ks_gen@ --- *
 475  *
 476  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 477  *              @const void *k@ = pointer to key material
 478  *              @size_t sz@ = size of the key material
 479  *
 480  * Returns:     The regeneration time for the new key.
 481  *
 482  * Use:         Derives a keyset from the given key material and adds it to
 483  *              the list.
 484  */
 485
 486 extern time_t ks_gen(keyset **/*ksroot*/, const void */*k*/, size_t /*sz*/);
 487
 488 /* --- @ks_encrypt@ --- *
 489  *
 490  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 491  *              @buf *b@ = pointer to input buffer
 492  *              @buf *bb@ = pointer to output buffer
 493  *
 494  * Returns:     Nonzero if a new key is needed.
 495  *
 496  * Use:         Encrypts a packet.
 497  */
 498
 499 extern int ks_encrypt(keyset **/*ksroot*/, buf */*b*/, buf */*bb*/);
 500
 501 /* --- @ks_decrypt@ --- *
 502  *
 503  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 504  *              @buf *b@ = pointer to input buffer
 505  *              @buf *bb@ = pointer to output buffer
 506  *
 507  * Returns:     Nonzero if the packet couldn't be decrypted.
 508  *
 509  * Use:         Decrypts a packet.
 510  */
 511
 512 extern int ks_decrypt(keyset **/*ksroot*/, buf */*b*/, buf */*bb*/);
 513
 514 /*----- Administration interface ------------------------------------------*/
 515
 516 /* --- @a_warn@ --- *
 517  *
 518  * Arguments:   @const char *fmt@ = pointer to format string
 519  *              @...@ = other arguments
 520  *
 521  * Returns:     ---
 522  *
 523  * Use:         Informs all admin connections of a warning.
 524  */
 525
 526 extern void a_warn(const char */*fmt*/, ...);
 527
 528 /* --- @a_create@ --- *
 529  *
 530  * Arguments:   @int fd_in, fd_out@ = file descriptors to use
 531  *
 532  * Returns:     ---
 533  *
 534  * Use:         Creates a new admin connection.
 535  */
 536
 537 extern void a_create(int /*fd_in*/, int /*fd_out*/);
 538
 539 /* --- @a_quit@ --- *
 540  *
 541  * Arguments:   ---
 542  *
 543  * Returns:     ---
 544  *
 545  * Use:         Shuts things down nicely.
 546  */
 547
 548 extern void a_quit(void);
 549
 550 /* --- @a_daemon@ --- *
 551  *
 552  * Arguments:   ---
 553  *
 554  * Returns:     ---
 555  *
 556  * Use:         Informs the admin module that it's a daemon.
 557  */
 558
 559 extern void a_daemon(void);
 560
 561 /* --- @a_init@ --- *
 562  *
 563  * Arguments:   @const char *sock@ = socket name to create
 564  *
 565  * Returns:     ---
 566  *
 567  * Use:         Creates the admin listening socket.
 568  */
 569
 570 extern void a_init(const char */*sock*/);
 571
 572 /*----- Peer management ---------------------------------------------------*/
 573
 574 /* --- @p_txstart@ --- *
 575  *
 576  * Arguments:   @peer *p@ = pointer to peer block
 577  *              @unsigned msg@ = message type code
 578  *
 579  * Returns:     A pointer to a buffer to write to.
 580  *
 581  * Use:         Starts sending to a peer.  Only one send can happen at a
 582  *              time.
 583  */
 584
 585 extern buf *p_txstart(peer */*p*/, unsigned /*msg*/);
 586
 587 /* --- @p_txend@ --- *
 588  *
 589  * Arguments:   @peer *p@ = pointer to peer block
 590  *
 591  * Returns:     ---
 592  *
 593  * Use:         Sends a packet to the peer.
 594  */
 595
 596 extern void p_txend(peer */*p*/);
 597
 598 /* --- @p_tun@ --- *
 599  *
 600  * Arguments:   @peer *p@ = pointer to peer block
 601  *              @buf *b@ = buffer containing incoming packet
 602  *
 603  * Returns:     ---
 604  *
 605  * Use:         Handles a packet which needs to be sent to a peer.
 606  */
 607
 608 extern void p_tun(peer */*p*/, buf */*b*/);
 609
 610 /* --- @p_interval@ --- *
 611  *
 612  * Arguments:   ---
 613  *
 614  * Returns:     ---
 615  *
 616  * Use:         Called periodically to do tidying.
 617  */
 618
 619 extern void p_interval(void);
 620
 621 /* --- @p_ifname@ --- *
 622  *
 623  * Arguments:   @peer *p@ = pointer to a peer block
 624  *
 625  * Returns:     A pointer to the peer's interface name.
 626  */
 627
 628 extern const char *p_ifname(peer */*p*/);
 629
 630 /* --- @p_addr@ --- *
 631  *
 632  * Arguments:   @peer *p@ = pointer to a peer block
 633  *
 634  * Returns:     A pointer to the peer's address.
 635  */
 636
 637 extern const addr *p_addr(peer */*p*/);
 638
 639 /* --- @p_init@ --- *
 640  *
 641  * Arguments:   @unsigned port@ = port number to listen to
 642  *
 643  * Returns:     ---
 644  *
 645  * Use:         Initializes the peer system; creates the socket.
 646  */
 647
 648 extern void p_init(unsigned /*port*/);
 649
 650 /* --- @p_port@ --- *
 651  *
 652  * Arguments:   ---
 653  *
 654  * Returns:     Port number used for socket.
 655  */
 656
 657 unsigned p_port(void);
 658
 659 /* --- @p_create@ --- *
 660  *
 661  * Arguments:   @const char *name@ = name for this peer
 662  *              @struct sockaddr *sa@ = socket address of peer
 663  *              @size_t sz@ = size of socket address
 664  *
 665  * Returns:     Pointer to the peer block, or null if it failed.
 666  *
 667  * Use:         Creates a new named peer block.  No peer is actually attached
 668  *              by this point.
 669  */
 670
 671 extern peer *p_create(const char */*name*/,
 672                       struct sockaddr */*sa*/, size_t /*sz*/);
 673
 674 /* --- @p_name@ --- *
 675  *
 676  * Arguments:   @peer *p@ = pointer to a peer block
 677  *
 678  * Returns:     A pointer to the peer's name.
 679  */
 680
 681 extern const char *p_name(peer */*p*/);
 682
 683 /* --- @p_find@ --- *
 684  *
 685  * Arguments:   @const char *name@ = name to look up
 686  *
 687  * Returns:     Pointer to the peer block, or null if not found.
 688  *
 689  * Use:         Finds a peer by name.
 690  */
 691
 692 extern peer *p_find(const char */*name*/);
 693
 694 /* --- @p_destroy@ --- *
 695  *
 696  * Arguments:   @peer *p@ = pointer to a peer
 697  *
 698  * Returns:     ---
 699  *
 700  * Use:         Destroys a peer.
 701  */
 702
 703 extern void p_destroy(peer */*p*/);
 704
 705 /* --- @p_first@, @p_next@ --- *
 706  *
 707  * Arguments:   @peer *p@ = a peer block
 708  *
 709  * Returns:     @peer_first@ returns the first peer in some ordering;
 710  *              @peer_next@ returns the peer following a given one in the
 711  *              same ordering.  Null is returned for the end of the list.
 712  */
 713
 714 extern peer *p_first(void);
 715 extern peer *p_next(peer */*p*/);
 716
 717 /*----- Tunnel interface --------------------------------------------------*/
 718
 719 /* --- @tun_init@ --- *
 720  *
 721  * Arguments:   ---
 722  *
 723  * Returns:     ---
 724  *
 725  * Use:         Initializes the tunneling system.  Maybe this will require
 726  *              opening file descriptors or something.
 727  */
 728
 729 extern void tun_init(void);
 730
 731 /* --- @tun_create@ --- *
 732  *
 733  * Arguments:   @tunnel *t@ = pointer to tunnel block
 734  *              @peer *p@ = pointer to peer block
 735  *
 736  * Returns:     Zero if it worked, nonzero on failure.
 737  *
 738  * Use:         Initializes a new tunnel.
 739  */
 740
 741 extern int tun_create(tunnel */*t*/, peer */*p*/);
 742
 743 /* --- @tun_ifname@ --- *
 744  *
 745  * Arguments:   @tunnel *t@ = pointer to tunnel block
 746  *
 747  * Returns:     A pointer to the tunnel's interface name.
 748  */
 749
 750 extern const char *tun_ifname(tunnel */*t*/);
 751
 752 /* --- @tun_inject@ --- *
 753  *
 754  * Arguments:   @tunnel *t@ = pointer to tunnel block
 755  *              @buf *b@ = buffer to send
 756  *
 757  * Returns:     ---
 758  *
 759  * Use:         Injects a packet into the local network stack.
 760  */
 761
 762 extern void tun_inject(tunnel */*t*/, buf */*b*/);
 763
 764 /* --- @tun_destroy@ --- *
 765  *
 766  * Arguments:   @tunnel *t@ = pointer to tunnel block
 767  *
 768  * Returns:     ---
 769  *
 770  * Use:         Destroys a tunnel.
 771  */
 772
 773 extern void tun_destroy(tunnel */*t*/);
 774
 775 /*----- Buffer handling ---------------------------------------------------*/
 776
 777 /* --- Useful macros --- */
 778
 779 #define BBASE(b) ((b)->base)
 780 #define BLIM(b) ((b)->limit)
 781 #define BCUR(b) ((b)->p)
 782 #define BSZ(b) ((b)->limit - (b)->base)
 783 #define BLEN(b) ((b)->p - (b)->base)
 784 #define BLEFT(b) ((b)->limit - (b)->p)
 785 #define BSTEP(b, sz) ((b)->p += (sz))
 786 #define BBAD(b) ((b)->f & BF_BROKEN)
 787 #define BOK(b) (!BBAD(b))
 788
 789 #define BENSURE(b, sz)                                                  \
 790   (BBAD(b) ? -1 : (sz) > BLEFT(b) ? (b)->f |= BF_BROKEN, -1 : 0)
 791
 792 /* --- @buf_init@ --- *
 793  *
 794  * Arguments:   @buf *b@ = pointer to a buffer block
 795  *              @void *p@ = pointer to a buffer
 796  *              @size_t sz@ = size of the buffer
 797  *
 798  * Returns:     ---
 799  *
 800  * Use:         Initializes the buffer block appropriately.
 801  */
 802
 803 extern void buf_init(buf */*b*/, void */*p*/, size_t /*sz*/);
 804
 805 /* --- @buf_break@ --- *
 806  *
 807  * Arguments:   @buf *b@ = pointer to a buffer block
 808  *
 809  * Returns:     Some negative value.
 810  *
 811  * Use:         Marks a buffer as broken.
 812  */
 813
 814 extern int buf_break(buf */*b*/);
 815
 816 /* --- @buf_ensure@ --- *
 817  *
 818  * Arguments:   @buf *b@ = pointer to a buffer block
 819  *              @size_t sz@ = size of data wanted
 820  *
 821  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 822  *
 823  * Use:         Ensures that there are @sz@ bytes still in the buffer.
 824  */
 825
 826 extern int buf_ensure(buf */*b*/, size_t /*sz*/);
 827
 828 /* --- @buf_get@ --- *
 829  *
 830  * Arguments:   @buf *b@ = pointer to a buffer block
 831  *              @void *p@ = pointer to a buffer
 832  *              @size_t sz@ = size of the buffer
 833  *
 834  * Returns:     Zero if it worked, nonzero if there wasn't enough data.
 835  *
 836  * Use:         Fetches data from the buffer into some other place.
 837  */
 838
 839 extern int buf_get(buf */*b*/, void */*p*/, size_t /*sz*/);
 840
 841 /* --- @buf_put@ --- *
 842  *
 843  * Arguments:   @buf *b@ = pointer to a buffer block
 844  *              @const void *p@ = pointer to a buffer
 845  *              @size_t sz@ = size of the buffer
 846  *
 847  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 848  *
 849  * Use:         Fetches data from some place and puts it in the buffer
 850  */
 851
 852 extern int buf_put(buf */*b*/, const void */*p*/, size_t /*sz*/);
 853
 854 /* --- @buf_getbyte@ --- *
 855  *
 856  * Arguments:   @buf *b@ = pointer to a buffer block
 857  *
 858  * Returns:     A byte, or less than zero if there wasn't a byte there.
 859  *
 860  * Use:         Gets a single byte from a buffer.
 861  */
 862
 863 extern int buf_getbyte(buf */*b*/);
 864
 865 /* --- @buf_putbyte@ --- *
 866  *
 867  * Arguments:   @buf *b@ = pointer to a buffer block
 868  *              @int ch@ = byte to write
 869  *
 870  * Returns:     Zero if OK, nonzero if there wasn't enough space.
 871  *
 872  * Use:         Puts a single byte in a buffer.
 873  */
 874
 875 extern int buf_putbyte(buf */*b*/, int /*ch*/);
 876
 877 /* --- @buf_getword@ --- *
 878  *
 879  * Arguments:   @buf *b@ = pointer to a buffer block
 880  *              @uint32 *w@ = where to put the word
 881  *
 882  * Returns:     Zero if OK, or nonzero if there wasn't a word there.
 883  *
 884  * Use:         Gets a 32-bit word from a buffer.
 885  */
 886
 887 extern int buf_getword(buf */*b*/, uint32 */*w*/);
 888
 889 /* --- @buf_putword@ --- *
 890  *
 891  * Arguments:   @buf *b@ = pointer to a buffer block
 892  *              @uint32 w@ = word to write
 893  *
 894  * Returns:     Zero if OK, nonzero if there wasn't enough space.
 895  *
 896  * Use:         Puts a 32-but word in a buffer.
 897  */
 898
 899 extern int buf_putword(buf */*b*/, uint32 /*w*/);
 900
 901 /* --- @buf_getmp@ --- *
 902  *
 903  * Arguments:   @buf *b@ = pointer to a buffer block
 904  *
 905  * Returns:     A multiprecision integer, or null if there wasn't one there.
 906  *
 907  * Use:         Gets a multiprecision integer from a buffer.
 908  */
 909
 910 extern mp *buf_getmp(buf */*b*/, mp */*d*/);
 911
 912 /* --- @buf_putmp@ --- *
 913  *
 914  * Arguments:   @buf *b@ = pointer to a buffer block
 915  *              @mp *m@ = a multiprecision integer
 916  *
 917  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 918  *
 919  * Use:         Puts a multiprecision integer to a buffer.
 920  */
 921
 922 extern int buf_putmp(buf */*b*/, mp */*m*/);
 923
 924 /*----- Other handy utilities ---------------------------------------------*/
 925
 926 /* --- @mpstr@ --- *
 927  *
 928  * Arguments:   @mp *m@ = a multiprecision integer
 929  *
 930  * Returns:     A pointer to the integer's textual representation.
 931  *
 932  * Use:         Converts a multiprecision integer to a string.  Corrupts
 933  *              @buf_o@.
 934  */
 935
 936 extern const char *mpstr(mp */*m*/);
 937
 938 /*----- That's all, folks -------------------------------------------------*/
 939
 940 #ifdef __cplusplus
 941   }
 942 #endif
 943
 944 #endif