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

   1 /* -*-c-*-
   2  *
   3  * $Id$
   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 #ifndef TRIPE_H
  30 #define TRIPE_H
  31
  32 #ifdef __cplusplus
  33   extern "C" {
  34 #endif
  35
  36 /*----- Header files ------------------------------------------------------*/
  37
  38 #include "config.h"
  39
  40 #include <assert.h>
  41 #include <ctype.h>
  42 #include <errno.h>
  43 #include <limits.h>
  44 #include <signal.h>
  45 #include <stdarg.h>
  46 #include <stddef.h>
  47 #include <stdio.h>
  48 #include <stdlib.h>
  49 #include <string.h>
  50 #include <time.h>
  51
  52 #include <sys/types.h>
  53 #include <sys/time.h>
  54 #include <unistd.h>
  55 #include <fcntl.h>
  56 #include <sys/stat.h>
  57
  58 #include <sys/socket.h>
  59 #include <sys/un.h>
  60 #include <netinet/in.h>
  61 #include <arpa/inet.h>
  62 #include <netdb.h>
  63
  64 #include <pwd.h>
  65 #include <grp.h>
  66
  67 #include <mLib/alloc.h>
  68 #include <mLib/arena.h>
  69 #include <mLib/bres.h>
  70 #include <mLib/dstr.h>
  71 #include <mLib/env.h>
  72 #include <mLib/fdflags.h>
  73 #include <mLib/fwatch.h>
  74 #include <mLib/mdwopt.h>
  75 #include <mLib/quis.h>
  76 #include <mLib/report.h>
  77 #include <mLib/sel.h>
  78 #include <mLib/selbuf.h>
  79 #include <mLib/sig.h>
  80 #include <mLib/str.h>
  81 #include <mLib/sub.h>
  82 #include <mLib/trace.h>
  83
  84 #include <catacomb/buf.h>
  85
  86 #include <catacomb/gcipher.h>
  87 #include <catacomb/gmac.h>
  88 #include <catacomb/grand.h>
  89 #include <catacomb/key.h>
  90 #include <catacomb/paranoia.h>
  91
  92 #include <catacomb/noise.h>
  93 #include <catacomb/rand.h>
  94
  95 #include <catacomb/mp.h>
  96 #include <catacomb/mprand.h>
  97 #include <catacomb/dh.h>
  98 #include <catacomb/ec.h>
  99 #include <catacomb/ec-keys.h>
 100 #include <catacomb/group.h>
 101
 102 #include "tripe-protocol.h"
 103 #include "util.h"
 104
 105 #undef sun
 106
 107 /*----- Magic numbers -----------------------------------------------------*/
 108
 109 /* --- Tunnel types --- */
 110
 111 #define TUN_NOTDEF 0
 112 #define TUN_UNET 1
 113 #define TUN_BSD 2
 114 #define TUN_LINUX 3
 115 #define TUN_SLIP 4
 116
 117 /* --- Trace flags --- */
 118
 119 #define T_TUNNEL 1u
 120 #define T_PEER 2u
 121 #define T_PACKET 4u
 122 #define T_ADMIN 8u
 123 #define T_CRYPTO 16u
 124 #define T_KEYSET 32u
 125 #define T_KEYEXCH 64u
 126 #define T_KEYMGMT 128u
 127
 128 #define T_ALL 255u
 129
 130 /* --- Units --- */
 131
 132 #define SEC(n) (n##u)
 133 #define MIN(n) (n##u * 60u)
 134 #define MEG(n) (n##ul * 1024ul * 1024ul)
 135
 136 /* --- Other things --- */
 137
 138 #define PKBUFSZ 65536
 139
 140 /*----- Cipher selections -------------------------------------------------*/
 141
 142 typedef struct algswitch {
 143   const gccipher *c;                    /* Symmetric encryption scheme */
 144   const gccipher *mgf;                  /* Mask-generation function */
 145   const gchash *h;                      /* Hash function */
 146   const gcmac *m;                       /* Message authentication code */
 147   size_t hashsz;                        /* Hash output size */
 148   size_t tagsz;                         /* Length to truncate MAC tags */
 149   size_t cksz, mksz;                    /* Key lengths for @c@ and @m@ */
 150 } algswitch;
 151
 152 extern algswitch algs;
 153
 154 #define MAXHASHSZ 64                    /* Largest possible hash size */
 155
 156 #define HASH_STRING(h, s) GH_HASH((h), (s), sizeof(s))
 157
 158 /*----- Data structures ---------------------------------------------------*/
 159
 160 /* --- Socket addresses --- *
 161  *
 162  * A magic union of supported socket addresses.
 163  */
 164
 165 typedef union addr {
 166   struct sockaddr sa;
 167   struct sockaddr_in sin;
 168 } addr;
 169
 170 /* --- A symmetric keyset --- *
 171  *
 172  * A keyset contains a set of symmetric keys for encrypting and decrypting
 173  * packets.  Keysets are stored in a list, sorted in reverse order of
 174  * creation, so that the most recent keyset (the one most likely to be used)
 175  * is first.
 176  *
 177  * Each keyset has a time limit and a data limit.  The keyset is destroyed
 178  * when either it has existed for too long, or it has been used to encrypt
 179  * too much data.  New key exchanges are triggered when keys are close to
 180  * expiry.
 181  */
 182
 183 typedef struct keyset {
 184   struct keyset *next;                  /* Next active keyset in the list */
 185   unsigned ref;                         /* Reference count for keyset */
 186   struct peer *p;                       /* Pointer to peer structure */
 187   time_t t_exp;                         /* Expiry time for this keyset */
 188   unsigned long sz_exp;                 /* Data limit for the keyset */
 189   T( unsigned seq; )                    /* Sequence number for tracing */
 190   unsigned f;                           /* Various useful flags */
 191   gcipher *cin, *cout;                  /* Keyset ciphers for encryption */
 192   size_t tagsz;                         /* Length to truncate MAC tags */
 193   gmac *min, *mout;                     /* Keyset MACs for integrity */
 194   uint32 oseq;                          /* Outbound sequence number */
 195   uint32 iseq, iwin;                    /* Inbound sequence number */
 196 } keyset;
 197
 198 #define KS_SEQWINSZ 32                  /* Bits in sequence number window */
 199
 200 #define KSF_LISTEN 1u                   /* Don't encrypt packets yet */
 201 #define KSF_LINK 2u                     /* Key is in a linked list */
 202
 203 /* --- Key exchange --- *
 204  *
 205  * TrIPE uses the Wrestlers Protocol for its key exchange.  The Wrestlers
 206  * Protocol has a number of desirable features (e.g., perfect forward
 207  * secrecy, and zero-knowledge authentication) which make it attractive for
 208  * use in TrIPE.  The Wrestlers Protocol was designed by Mark Wooding and
 209  * Clive Jones.
 210  */
 211
 212 #define KX_NCHAL 16u
 213 #define KX_THRESH 4u
 214
 215 typedef struct kxchal {
 216   struct keyexch *kx;                   /* Pointer back to key exchange */
 217   ge *c;                                /* Responder's challenge */
 218   ge *r;                                /* My reply to the challenge */
 219   keyset *ks;                           /* Pointer to temporary keyset */
 220   unsigned f;                           /* Various useful flags */
 221   sel_timer t;                          /* Response timer for challenge */
 222   octet hc[MAXHASHSZ];                  /* Hash of his challenge */
 223   mp *ck;                               /* The check value */
 224   octet hswrq_in[MAXHASHSZ];            /* Inbound switch request message */
 225   octet hswok_in[MAXHASHSZ];            /* Inbound switch confirmation */
 226   octet hswrq_out[MAXHASHSZ];           /* Outbound switch request message */
 227   octet hswok_out[MAXHASHSZ];           /* Outbound switch confirmation */
 228 } kxchal;
 229
 230 typedef struct keyexch {
 231   struct peer *p;                       /* Pointer back to the peer */
 232   keyset **ks;                          /* Peer's list of keysets */
 233   unsigned f;                           /* Various useful flags */
 234   unsigned s;                           /* Current state in exchange */
 235   sel_timer t;                          /* Timer for next exchange */
 236   ge *kpub;                             /* Peer's public key */
 237   time_t texp_kpub;                     /* Expiry time for public key */
 238   mp *alpha;                            /* My temporary secret */
 239   ge *c;                                /* My challenge */
 240   ge *rx;                               /* The expected response */
 241   unsigned nr;                          /* Number of extant responses */
 242   time_t t_valid;                       /* When this exchange goes bad */
 243   octet hc[MAXHASHSZ];                  /* Hash of my challenge */
 244   kxchal *r[KX_NCHAL];                  /* Array of challenges */
 245 } keyexch;
 246
 247 #define KXF_TIMER 1u                    /* Waiting for a timer to go off */
 248 #define KXF_DEAD 2u                     /* The key-exchanger isn't up */
 249 #define KXF_PUBKEY 4u                   /* Key exchanger has a public key */
 250
 251 enum {
 252   KXS_DEAD,                             /* Uninitialized state (magical) */
 253   KXS_CHAL,                             /* Main answer-challenges state */
 254   KXS_COMMIT,                           /* Committed: send switch request */
 255   KXS_SWITCH                            /* Switched: send confirmation */
 256 };
 257
 258 /* --- Tunnel structure --- *
 259  *
 260  * Used to maintain system-specific information about the tunnel interface.
 261  */
 262
 263 #if TUN_TYPE == TUN_LINUX
 264 #  include <linux/if.h>
 265 #  include <linux/if_tun.h>
 266 #endif
 267
 268 #if TUN_TYPE == TUN_SLIP
 269   typedef struct slipif {
 270     struct slipif *next;                /* Next one in the list */
 271     int ifd, ofd;                       /* File descriptors to talk on */
 272     char *name;                         /* Interface name */
 273     unsigned f;                         /* Various flags */
 274 #     define SLIPIFF_INUSE 1u           /*   Interface is in use */
 275   } slipif;
 276 #endif
 277
 278 typedef struct tunnel {
 279 #if TUN_TYPE == TUN_UNET
 280   sel_file f;                           /* Selector for Usernet device */
 281   struct peer *p;                       /* Pointer to my peer */
 282 #elif TUN_TYPE == TUN_LINUX
 283   sel_file f;                           /* Selector for TUN/TAP device */
 284   struct peer *p;                       /* Pointer to my peer */
 285   char ifn[IFNAMSIZ];                   /* Interface name buffer */
 286 #elif TUN_TYPE == TUN_BSD
 287   sel_file f;                           /* Selector for tunnel device */
 288   struct peer *p;                       /* Pointer to my peer */
 289   unsigned n;                           /* Number of my tunnel device */
 290 #elif TUN_TYPE == TUN_SLIP
 291   slipif *sl;                           /* My interface record */
 292   sel_file f;                           /* Selector for SLIP tty */
 293   struct peer *p;                       /* Pointer to my peer */
 294   unsigned st;                          /* Current parser state */
 295 #   define SLIPST_ESC 1u                /*   Last saw an escape character */
 296 #   define SLIPST_BAD 2u                /*   This packet is malformed */
 297 #   define SLIPST_EOF 4u                /*   File descriptor reported EOF */
 298   size_t n;                             /* Number of bytes used in buffer */
 299   octet buf[PKBUFSZ];                   /* Buffer for incoming data */
 300 #else
 301 #  error "No support for this tunnel type"
 302 #endif
 303 } tunnel;
 304
 305 /* --- Peer statistics --- *
 306  *
 307  * Contains various interesting and not-so-interesting statistics about a
 308  * peer.  This is updated by various parts of the code.  The format of the
 309  * structure isn't considered private, and @p_stats@ returns a pointer to the
 310  * statistics block for a given peer.
 311  */
 312
 313 typedef struct stats {
 314   unsigned long sz_in, sz_out;          /* Size of all data in and out */
 315   unsigned long sz_kxin, sz_kxout;      /* Size of key exchange messages */
 316   unsigned long sz_ipin, sz_ipout;      /* Size of encapsulated IP packets */
 317   time_t t_start, t_last, t_kx;         /* Time peer created, last pk, kx */
 318   unsigned long n_reject;               /* Number of rejected packets */
 319   unsigned long n_in, n_out;            /* Number of packets in and out */
 320   unsigned long n_kxin, n_kxout;        /* Number of key exchange packets */
 321   unsigned long n_ipin, n_ipout;        /* Number of encrypted packets */
 322 } stats;
 323
 324 /* --- Peer structure --- *
 325  *
 326  * The main structure which glues everything else together.
 327  */
 328
 329 typedef struct peer {
 330   struct peer *next, *prev;             /* Links to next and previous */
 331   char *name;                           /* Name of this peer */
 332   tunnel t;                             /* Tunnel for local packets */
 333   keyset *ks;                           /* List head for keysets */
 334   buf b;                                /* Buffer for sending packets */
 335   addr peer;                            /* Peer socket address */
 336   size_t sasz;                          /* Socket address size */
 337   stats st;                             /* Statistics */
 338   keyexch kx;                           /* Key exchange protocol block */
 339 } peer;
 340
 341 /* --- Admin structure --- */
 342
 343 #define OBUFSZ 16384u
 344
 345 typedef struct obuf {
 346   struct obuf *next;                    /* Next buffer in list */
 347   char *p_in, *p_out;                   /* Pointers into the buffer */
 348   char buf[OBUFSZ];                     /* The actual buffer */
 349 } obuf;
 350
 351 typedef struct admin {
 352   struct admin *next, *prev;            /* Links to next and previous */
 353   unsigned f;                           /* Various useful flags */
 354 #ifndef NTRACE
 355   unsigned seq;                         /* Sequence number for tracing */
 356 #endif
 357   char *pname;                          /* Peer name to create */
 358   char *paddr;                          /* Address string to resolve */
 359   obuf *o_head, *o_tail;                /* Output buffer list */
 360   selbuf b;                             /* Line buffer for commands */
 361   sel_file w;                           /* Selector for write buffering */
 362   bres_client r;                        /* Background resolver task */
 363   sel_timer t;                          /* Timer for resolver */
 364   addr peer;                            /* Address to set */
 365   size_t sasz;                          /* Size of the address */
 366 } admin;
 367
 368 #define AF_DEAD 1u                      /* Destroy this admin block */
 369 #define AF_LOCK 2u                      /* Don't destroy it yet */
 370 #define AF_NOTE 4u                      /* Catch notifications */
 371 #ifndef NTRACE
 372   #define AF_TRACE 8u                   /* Catch tracing */
 373 #endif
 374 #define AF_WARN 16u                     /* Catch warning messages */
 375
 376 #ifndef NTRACE
 377 #  define AF_ALLMSGS (AF_NOTE | AF_TRACE | AF_WARN)
 378 #else
 379 #  define AF_ALLMSGS (AF_NOTE | AF_WARN)
 380 #endif
 381
 382 /*----- Global variables --------------------------------------------------*/
 383
 384 extern sel_state sel;                   /* Global I/O event state */
 385 extern group *gg;                       /* The group we work in */
 386 extern mp *kpriv;                       /* Our private key */
 387 extern octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ];
 388
 389 #ifndef NTRACE
 390 extern const trace_opt tr_opts[];       /* Trace options array */
 391 extern unsigned tr_flags;               /* Trace options flags */
 392 #endif
 393
 394 /*----- Other macros ------------------------------------------------------*/
 395
 396 #define TIMER noise_timer(RAND_GLOBAL)
 397
 398 /*----- Key management ----------------------------------------------------*/
 399
 400 /* --- @km_interval@ --- *
 401  *
 402  * Arguments:   ---
 403  *
 404  * Returns:     Zero if OK, nonzero to force reloading of keys.
 405  *
 406  * Use:         Called on the interval timer to perform various useful jobs.
 407  */
 408
 409 extern int km_interval(void);
 410
 411 /* --- @km_init@ --- *
 412  *
 413  * Arguments:   @const char *kr_priv@ = private keyring file
 414  *              @const char *kr_pub@ = public keyring file
 415  *              @const char *tag@ = tag to load
 416  *
 417  * Returns:     ---
 418  *
 419  * Use:         Initializes, and loads the private key.
 420  */
 421
 422 extern void km_init(const char */*kr_priv*/, const char */*kr_pub*/,
 423                     const char */*tag*/);
 424
 425 /* --- @km_getpubkey@ --- *
 426  *
 427  * Arguments:   @const char *tag@ = public key tag to load
 428  *              @ge *kpub@ = where to put the public key
 429  *              @time_t *t_exp@ = where to put the expiry time
 430  *
 431  * Returns:     Zero if OK, nonzero if it failed.
 432  *
 433  * Use:         Fetches a public key from the keyring.
 434  */
 435
 436 extern int km_getpubkey(const char */*tag*/, ge */*kpub*/,
 437                         time_t */*t_exp*/);
 438
 439 /*----- Key exchange ------------------------------------------------------*/
 440
 441 /* --- @kx_start@ --- *
 442  *
 443  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 444  *
 445  * Returns:     ---
 446  *
 447  * Use:         Stimulates a key exchange.  If a key exchage is in progress,
 448  *              a new challenge is sent (unless the quiet timer forbids
 449  *              this); if no exchange is in progress, one is commenced.
 450  */
 451
 452 extern void kx_start(keyexch */*kx*/);
 453
 454 /* --- @kx_message@ --- *
 455  *
 456  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 457  *              @unsigned msg@ = the message code
 458  *              @buf *b@ = pointer to buffer containing the packet
 459  *
 460  * Returns:     ---
 461  *
 462  * Use:         Reads a packet containing key exchange messages and handles
 463  *              it.
 464  */
 465
 466 extern void kx_message(keyexch */*kx*/, unsigned /*msg*/, buf */*b*/);
 467
 468 /* --- @kx_free@ --- *
 469  *
 470  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 471  *
 472  * Returns:     ---
 473  *
 474  * Use:         Frees everything in a key exchange context.
 475  */
 476
 477 extern void kx_free(keyexch */*kx*/);
 478
 479 /* --- @kx_newkeys@ --- *
 480  *
 481  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 482  *
 483  * Returns:     ---
 484  *
 485  * Use:         Informs the key exchange module that its keys may have
 486  *              changed.  If fetching the new keys fails, the peer will be
 487  *              destroyed, we log messages and struggle along with the old
 488  *              keys.
 489  */
 490
 491 extern void kx_newkeys(keyexch */*kx*/);
 492
 493 /* --- @kx_init@ --- *
 494  *
 495  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 496  *              @peer *p@ = pointer to peer context
 497  *              @keyset **ks@ = pointer to keyset list
 498  *
 499  * Returns:     Zero if OK, nonzero if it failed.
 500  *
 501  * Use:         Initializes a key exchange module.  The module currently
 502  *              contains no keys, and will attempt to initiate a key
 503  *              exchange.
 504  */
 505
 506 extern int kx_init(keyexch */*kx*/, peer */*p*/, keyset **/*ks*/);
 507
 508 /*----- Keysets and symmetric cryptography --------------------------------*/
 509
 510 /* --- @ks_drop@ --- *
 511  *
 512  * Arguments:   @keyset *ks@ = pointer to a keyset
 513  *
 514  * Returns:     ---
 515  *
 516  * Use:         Decrements a keyset's reference counter.  If the counter hits
 517  *              zero, the keyset is freed.
 518  */
 519
 520 extern void ks_drop(keyset */*ks*/);
 521
 522 /* --- @ks_gen@ --- *
 523  *
 524  * Arguments:   @const void *k@ = pointer to key material
 525  *              @size_t x, y, z@ = offsets into key material (see below)
 526  *              @peer *p@ = pointer to peer information
 527  *
 528  * Returns:     A pointer to the new keyset.
 529  *
 530  * Use:         Derives a new keyset from the given key material.  The
 531  *              offsets @x@, @y@ and @z@ separate the key material into three
 532  *              parts.  Between the @k@ and @k + x@ is `my' contribution to
 533  *              the key material; between @k + x@ and @k + y@ is `your'
 534  *              contribution; and between @k + y@ and @k + z@ is a shared
 535  *              value we made together.  These are used to construct two
 536  *              pairs of symmetric keys.  Each pair consists of an encryption
 537  *              key and a message authentication key.  One pair is used for
 538  *              outgoing messages, the other for incoming messages.
 539  *
 540  *              The new key is marked so that it won't be selected for output
 541  *              by @ksl_encrypt@.  You can still encrypt data with it by
 542  *              calling @ks_encrypt@ directly.
 543  */
 544
 545 extern keyset *ks_gen(const void */*k*/,
 546                       size_t /*x*/, size_t /*y*/, size_t /*z*/,
 547                       peer */*p*/);
 548
 549 /* --- @ks_tregen@ --- *
 550  *
 551  * Arguments:   @keyset *ks@ = pointer to a keyset
 552  *
 553  * Returns:     The time at which moves ought to be made to replace this key.
 554  */
 555
 556 extern time_t ks_tregen(keyset */*ks*/);
 557
 558 /* --- @ks_activate@ --- *
 559  *
 560  * Arguments:   @keyset *ks@ = pointer to a keyset
 561  *
 562  * Returns:     ---
 563  *
 564  * Use:         Activates a keyset, so that it can be used for encrypting
 565  *              outgoing messages.
 566  */
 567
 568 extern void ks_activate(keyset */*ks*/);
 569
 570 /* --- @ks_encrypt@ --- *
 571  *
 572  * Arguments:   @keyset *ks@ = pointer to a keyset
 573  *              @unsigned ty@ = message type
 574  *              @buf *b@ = pointer to input buffer
 575  *              @buf *bb@ = pointer to output buffer
 576  *
 577  * Returns:     Zero if OK, nonzero if the key needs replacing.  If the
 578  *              encryption failed, the output buffer is broken and zero is
 579  *              returned.
 580  *
 581  * Use:         Encrypts a block of data using the key.  Note that the `key
 582  *              ought to be replaced' notification is only ever given once
 583  *              for each key.  Also note that this call forces a keyset to be
 584  *              used even if it's marked as not for data output.
 585  */
 586
 587 extern int ks_encrypt(keyset */*ks*/, unsigned /*ty*/,
 588                       buf */*b*/, buf */*bb*/);
 589
 590 /* --- @ks_decrypt@ --- *
 591  *
 592  * Arguments:   @keyset *ks@ = pointer to a keyset
 593  *              @unsigned ty@ = expected type code
 594  *              @buf *b@ = pointer to an input buffer
 595  *              @buf *bb@ = pointer to an output buffer
 596  *
 597  * Returns:     Zero on success, or nonzero if there was some problem.
 598  *
 599  * Use:         Attempts to decrypt a message using a given key.  Note that
 600  *              requesting decryption with a key directly won't clear a
 601  *              marking that it's not for encryption.
 602  */
 603
 604 extern int ks_decrypt(keyset */*ks*/, unsigned /*ty*/,
 605                       buf */*b*/, buf */*bb*/);
 606
 607 /* --- @ksl_free@ --- *
 608  *
 609  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 610  *
 611  * Returns:     ---
 612  *
 613  * Use:         Frees (releases references to) all of the keys in a keyset.
 614  */
 615
 616 extern void ksl_free(keyset **/*ksroot*/);
 617
 618 /* --- @ksl_link@ --- *
 619  *
 620  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 621  *              @keyset *ks@ = pointer to a keyset
 622  *
 623  * Returns:     ---
 624  *
 625  * Use:         Links a keyset into a list.  A keyset can only be on one list
 626  *              at a time.  Bad things happen otherwise.
 627  */
 628
 629 extern void ksl_link(keyset **/*ksroot*/, keyset */*ks*/);
 630
 631 /* --- @ksl_prune@ --- *
 632  *
 633  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 634  *
 635  * Returns:     ---
 636  *
 637  * Use:         Prunes the keyset list by removing keys which mustn't be used
 638  *              any more.
 639  */
 640
 641 extern void ksl_prune(keyset **/*ksroot*/);
 642
 643 /* --- @ksl_encrypt@ --- *
 644  *
 645  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 646  *              @unsigned ty@ = message type
 647  *              @buf *b@ = pointer to input buffer
 648  *              @buf *bb@ = pointer to output buffer
 649  *
 650  * Returns:     Nonzero if a new key is needed.
 651  *
 652  * Use:         Encrypts a packet.
 653  */
 654
 655 extern int ksl_encrypt(keyset **/*ksroot*/, unsigned /*ty*/,
 656                        buf */*b*/, buf */*bb*/);
 657
 658 /* --- @ksl_decrypt@ --- *
 659  *
 660  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 661  *              @unsigned ty@ = expected type code
 662  *              @buf *b@ = pointer to input buffer
 663  *              @buf *bb@ = pointer to output buffer
 664  *
 665  * Returns:     Nonzero if the packet couldn't be decrypted.
 666  *
 667  * Use:         Decrypts a packet.
 668  */
 669
 670 extern int ksl_decrypt(keyset **/*ksroot*/, unsigned /*ty*/,
 671                        buf */*b*/, buf */*bb*/);
 672
 673 /*----- Administration interface ------------------------------------------*/
 674
 675 /* --- @a_warn@ --- *
 676  *
 677  * Arguments:   @const char *fmt@ = pointer to format string
 678  *              @...@ = other arguments
 679  *
 680  * Returns:     ---
 681  *
 682  * Use:         Informs all admin connections of a warning.
 683  */
 684
 685 extern void a_warn(const char */*fmt*/, ...);
 686
 687 /* --- @a_notify@ --- *
 688  *
 689  * Arguments:   @const char *fmt@ = pointer to format string
 690  *              @...@ = other arguments
 691  *
 692  * Returns:     ---
 693  *
 694  * Use:         Sends a notification to interested admin connections.
 695  */
 696
 697 extern void a_notify(const char */*fmt*/, ...);
 698
 699 /* --- @a_create@ --- *
 700  *
 701  * Arguments:   @int fd_in, fd_out@ = file descriptors to use
 702  *              @unsigned f@ = initial flags to set
 703  *
 704  * Returns:     ---
 705  *
 706  * Use:         Creates a new admin connection.
 707  */
 708
 709 extern void a_create(int /*fd_in*/, int /*fd_out*/, unsigned /*f*/);
 710
 711 /* --- @a_quit@ --- *
 712  *
 713  * Arguments:   ---
 714  *
 715  * Returns:     ---
 716  *
 717  * Use:         Shuts things down nicely.
 718  */
 719
 720 extern void a_quit(void);
 721
 722 /* --- @a_daemon@ --- *
 723  *
 724  * Arguments:   ---
 725  *
 726  * Returns:     ---
 727  *
 728  * Use:         Informs the admin module that it's a daemon.
 729  */
 730
 731 extern void a_daemon(void);
 732
 733 /* --- @a_init@ --- *
 734  *
 735  * Arguments:   @const char *sock@ = socket name to create
 736  *
 737  * Returns:     ---
 738  *
 739  * Use:         Creates the admin listening socket.
 740  */
 741
 742 extern void a_init(const char */*sock*/);
 743
 744 /*----- Peer management ---------------------------------------------------*/
 745
 746 /* --- @p_txstart@ --- *
 747  *
 748  * Arguments:   @peer *p@ = pointer to peer block
 749  *              @unsigned msg@ = message type code
 750  *
 751  * Returns:     A pointer to a buffer to write to.
 752  *
 753  * Use:         Starts sending to a peer.  Only one send can happen at a
 754  *              time.
 755  */
 756
 757 extern buf *p_txstart(peer */*p*/, unsigned /*msg*/);
 758
 759 /* --- @p_txend@ --- *
 760  *
 761  * Arguments:   @peer *p@ = pointer to peer block
 762  *
 763  * Returns:     ---
 764  *
 765  * Use:         Sends a packet to the peer.
 766  */
 767
 768 extern void p_txend(peer */*p*/);
 769
 770 /* --- @p_tun@ --- *
 771  *
 772  * Arguments:   @peer *p@ = pointer to peer block
 773  *              @buf *b@ = buffer containing incoming packet
 774  *
 775  * Returns:     ---
 776  *
 777  * Use:         Handles a packet which needs to be sent to a peer.
 778  */
 779
 780 extern void p_tun(peer */*p*/, buf */*b*/);
 781
 782 /* --- @p_interval@ --- *
 783  *
 784  * Arguments:   ---
 785  *
 786  * Returns:     ---
 787  *
 788  * Use:         Called periodically to do tidying.
 789  */
 790
 791 extern void p_interval(void);
 792
 793 /* --- @p_stats@ --- *
 794  *
 795  * Arguments:   @peer *p@ = pointer to a peer block
 796  *
 797  * Returns:     A pointer to the peer's statistics.
 798  */
 799
 800 extern stats *p_stats(peer */*p*/);
 801
 802 /* --- @p_ifname@ --- *
 803  *
 804  * Arguments:   @peer *p@ = pointer to a peer block
 805  *
 806  * Returns:     A pointer to the peer's interface name.
 807  */
 808
 809 extern const char *p_ifname(peer */*p*/);
 810
 811 /* --- @p_addr@ --- *
 812  *
 813  * Arguments:   @peer *p@ = pointer to a peer block
 814  *
 815  * Returns:     A pointer to the peer's address.
 816  */
 817
 818 extern const addr *p_addr(peer */*p*/);
 819
 820 /* --- @p_init@ --- *
 821  *
 822  * Arguments:   @struct in_addr addr@ = address to bind to
 823  *              @unsigned port@ = port number to listen to
 824  *
 825  * Returns:     ---
 826  *
 827  * Use:         Initializes the peer system; creates the socket.
 828  */
 829
 830 extern void p_init(struct in_addr /*addr*/, unsigned /*port*/);
 831
 832 /* --- @p_port@ --- *
 833  *
 834  * Arguments:   ---
 835  *
 836  * Returns:     Port number used for socket.
 837  */
 838
 839 unsigned p_port(void);
 840
 841 /* --- @p_create@ --- *
 842  *
 843  * Arguments:   @const char *name@ = name for this peer
 844  *              @struct sockaddr *sa@ = socket address of peer
 845  *              @size_t sz@ = size of socket address
 846  *
 847  * Returns:     Pointer to the peer block, or null if it failed.
 848  *
 849  * Use:         Creates a new named peer block.  No peer is actually attached
 850  *              by this point.
 851  */
 852
 853 extern peer *p_create(const char */*name*/,
 854                       struct sockaddr */*sa*/, size_t /*sz*/);
 855
 856 /* --- @p_name@ --- *
 857  *
 858  * Arguments:   @peer *p@ = pointer to a peer block
 859  *
 860  * Returns:     A pointer to the peer's name.
 861  */
 862
 863 extern const char *p_name(peer */*p*/);
 864
 865 /* --- @p_find@ --- *
 866  *
 867  * Arguments:   @const char *name@ = name to look up
 868  *
 869  * Returns:     Pointer to the peer block, or null if not found.
 870  *
 871  * Use:         Finds a peer by name.
 872  */
 873
 874 extern peer *p_find(const char */*name*/);
 875
 876 /* --- @p_destroy@ --- *
 877  *
 878  * Arguments:   @peer *p@ = pointer to a peer
 879  *
 880  * Returns:     ---
 881  *
 882  * Use:         Destroys a peer.
 883  */
 884
 885 extern void p_destroy(peer */*p*/);
 886
 887 /* --- @p_first@, @p_next@ --- *
 888  *
 889  * Arguments:   @peer *p@ = a peer block
 890  *
 891  * Returns:     @peer_first@ returns the first peer in some ordering;
 892  *              @peer_next@ returns the peer following a given one in the
 893  *              same ordering.  Null is returned for the end of the list.
 894  */
 895
 896 extern peer *p_first(void);
 897 extern peer *p_next(peer */*p*/);
 898
 899 /*----- Tunnel interface --------------------------------------------------*/
 900
 901 /* --- @tun_init@ --- *
 902  *
 903  * Arguments:   ---
 904  *
 905  * Returns:     ---
 906  *
 907  * Use:         Initializes the tunneling system.  Maybe this will require
 908  *              opening file descriptors or something.
 909  */
 910
 911 extern void tun_init(void);
 912
 913 /* --- @tun_create@ --- *
 914  *
 915  * Arguments:   @tunnel *t@ = pointer to tunnel block
 916  *              @peer *p@ = pointer to peer block
 917  *
 918  * Returns:     Zero if it worked, nonzero on failure.
 919  *
 920  * Use:         Initializes a new tunnel.
 921  */
 922
 923 extern int tun_create(tunnel */*t*/, peer */*p*/);
 924
 925 /* --- @tun_ifname@ --- *
 926  *
 927  * Arguments:   @tunnel *t@ = pointer to tunnel block
 928  *
 929  * Returns:     A pointer to the tunnel's interface name.
 930  */
 931
 932 extern const char *tun_ifname(tunnel */*t*/);
 933
 934 /* --- @tun_inject@ --- *
 935  *
 936  * Arguments:   @tunnel *t@ = pointer to tunnel block
 937  *              @buf *b@ = buffer to send
 938  *
 939  * Returns:     ---
 940  *
 941  * Use:         Injects a packet into the local network stack.
 942  */
 943
 944 extern void tun_inject(tunnel */*t*/, buf */*b*/);
 945
 946 /* --- @tun_destroy@ --- *
 947  *
 948  * Arguments:   @tunnel *t@ = pointer to tunnel block
 949  *
 950  * Returns:     ---
 951  *
 952  * Use:         Destroys a tunnel.
 953  */
 954
 955 extern void tun_destroy(tunnel */*t*/);
 956
 957 /*----- Other handy utilities ---------------------------------------------*/
 958
 959 /* --- @mpstr@ --- *
 960  *
 961  * Arguments:   @mp *m@ = a multiprecision integer
 962  *
 963  * Returns:     A pointer to the integer's textual representation.
 964  *
 965  * Use:         Converts a multiprecision integer to a string.  Corrupts
 966  *              @buf_t@.
 967  */
 968
 969 extern const char *mpstr(mp */*m*/);
 970
 971 /* --- @gestr@ --- *
 972  *
 973  * Arguments:   @group *g@ = a group
 974  *              @ge *x@ = a group element
 975  *
 976  * Returns:     A pointer to the element's textual representation.
 977  *
 978  * Use:         Converts a group element to a string.  Corrupts
 979  *              @buf_t@.
 980  */
 981
 982 extern const char *gestr(group */*g*/, ge */*x*/);
 983
 984 /* --- @timestr@ --- *
 985  *
 986  * Arguments:   @time_t t@ = a time to convert
 987  *
 988  * Returns:     A pointer to a textual representation of the time.
 989  *
 990  * Use:         Converts a time to a textual representation.  Corrupts
 991  *              @buf_t@.
 992  */
 993
 994 extern const char *timestr(time_t /*t*/);
 995
 996 /*----- That's all, folks -------------------------------------------------*/
 997
 998 #ifdef __cplusplus
 999   }
1000 #endif
1001
1002 #endif