mdw@git.distorted.org.uk Git - tripe/blob - server/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/base64.h>
  70 #include <mLib/bres.h>
  71 #include <mLib/dstr.h>
  72 #include <mLib/env.h>
  73 #include <mLib/fdflags.h>
  74 #include <mLib/fwatch.h>
  75 #include <mLib/mdwopt.h>
  76 #include <mLib/quis.h>
  77 #include <mLib/report.h>
  78 #include <mLib/sel.h>
  79 #include <mLib/selbuf.h>
  80 #include <mLib/sig.h>
  81 #include <mLib/str.h>
  82 #include <mLib/sub.h>
  83 #include <mLib/trace.h>
  84 #include <mLib/tv.h>
  85
  86 #include <catacomb/buf.h>
  87
  88 #include <catacomb/gcipher.h>
  89 #include <catacomb/gmac.h>
  90 #include <catacomb/grand.h>
  91 #include <catacomb/key.h>
  92 #include <catacomb/paranoia.h>
  93
  94 #include <catacomb/noise.h>
  95 #include <catacomb/rand.h>
  96
  97 #include <catacomb/mp.h>
  98 #include <catacomb/mprand.h>
  99 #include <catacomb/dh.h>
 100 #include <catacomb/ec.h>
 101 #include <catacomb/ec-keys.h>
 102 #include <catacomb/group.h>
 103
 104 #include "protocol.h"
 105 #include "util.h"
 106
 107 #undef sun
 108
 109 /*----- Magic numbers -----------------------------------------------------*/
 110
 111 /* --- Trace flags --- */
 112
 113 #define T_TUNNEL 1u
 114 #define T_PEER 2u
 115 #define T_PACKET 4u
 116 #define T_ADMIN 8u
 117 #define T_CRYPTO 16u
 118 #define T_KEYSET 32u
 119 #define T_KEYEXCH 64u
 120 #define T_KEYMGMT 128u
 121 #define T_CHAL 256u
 122
 123 #define T_ALL 511u
 124
 125 /* --- Units --- */
 126
 127 #define SEC(n) (n##u)
 128 #define MIN(n) (n##u * 60u)
 129 #define MEG(n) (n##ul * 1024ul * 1024ul)
 130
 131 /* --- Other things --- */
 132
 133 #define PKBUFSZ 65536
 134
 135 /*----- Cipher selections -------------------------------------------------*/
 136
 137 typedef struct algswitch {
 138   const gccipher *c;                    /* Symmetric encryption scheme */
 139   const gccipher *mgf;                  /* Mask-generation function */
 140   const gchash *h;                      /* Hash function */
 141   const gcmac *m;                       /* Message authentication code */
 142   size_t hashsz;                        /* Hash output size */
 143   size_t tagsz;                         /* Length to truncate MAC tags */
 144   size_t cksz, mksz;                    /* Key lengths for @c@ and @m@ */
 145 } algswitch;
 146
 147 extern algswitch algs;
 148
 149 #define MAXHASHSZ 64                    /* Largest possible hash size */
 150
 151 #define HASH_STRING(h, s) GH_HASH((h), (s), sizeof(s))
 152
 153 /*----- Data structures ---------------------------------------------------*/
 154
 155 /* --- Socket addresses --- *
 156  *
 157  * A magic union of supported socket addresses.
 158  */
 159
 160 typedef union addr {
 161   struct sockaddr sa;
 162   struct sockaddr_in sin;
 163 } addr;
 164
 165 /* --- Sequence number checking --- */
 166
 167 typedef struct seqwin {
 168   uint32 seq;                           /* First acceptable input sequence */
 169   uint32 win;                           /* Window of acceptable numbers */
 170 } seqwin;
 171
 172 #define SEQ_WINSZ 32                    /* Bits in sequence number window */
 173
 174 /* --- A symmetric keyset --- *
 175  *
 176  * A keyset contains a set of symmetric keys for encrypting and decrypting
 177  * packets.  Keysets are stored in a list, sorted in reverse order of
 178  * creation, so that the most recent keyset (the one most likely to be used)
 179  * is first.
 180  *
 181  * Each keyset has a time limit and a data limit.  The keyset is destroyed
 182  * when either it has existed for too long, or it has been used to encrypt
 183  * too much data.  New key exchanges are triggered when keys are close to
 184  * expiry.
 185  */
 186
 187 typedef struct keyset {
 188   struct keyset *next;                  /* Next active keyset in the list */
 189   unsigned ref;                         /* Reference count for keyset */
 190   struct peer *p;                       /* Pointer to peer structure */
 191   time_t t_exp;                         /* Expiry time for this keyset */
 192   unsigned long sz_exp;                 /* Data limit for the keyset */
 193   T( unsigned seq; )                    /* Sequence number for tracing */
 194   unsigned f;                           /* Various useful flags */
 195   gcipher *cin, *cout;                  /* Keyset ciphers for encryption */
 196   size_t tagsz;                         /* Length to truncate MAC tags */
 197   gmac *min, *mout;                     /* Keyset MACs for integrity */
 198   uint32 oseq;                          /* Outbound sequence number */
 199   seqwin iseq;                          /* Inbound sequence number */
 200 } keyset;
 201
 202 #define KSF_LISTEN 1u                   /* Don't encrypt packets yet */
 203 #define KSF_LINK 2u                     /* Key is in a linked list */
 204
 205 /* --- Key exchange --- *
 206  *
 207  * TrIPE uses the Wrestlers Protocol for its key exchange.  The Wrestlers
 208  * Protocol has a number of desirable features (e.g., perfect forward
 209  * secrecy, and zero-knowledge authentication) which make it attractive for
 210  * use in TrIPE.  The Wrestlers Protocol was designed by Mark Wooding and
 211  * Clive Jones.
 212  */
 213
 214 #define KX_NCHAL 16u
 215
 216 typedef struct kxchal {
 217   struct keyexch *kx;                   /* Pointer back to key exchange */
 218   ge *c;                                /* Responder's challenge */
 219   ge *r;                                /* My reply to the challenge */
 220   keyset *ks;                           /* Pointer to temporary keyset */
 221   unsigned f;                           /* Various useful flags */
 222   sel_timer t;                          /* Response timer for challenge */
 223   octet hc[MAXHASHSZ];                  /* Hash of his challenge */
 224   octet ck[MAXHASHSZ];                  /* His magical check value */
 225   octet hswrq_in[MAXHASHSZ];            /* Inbound switch request message */
 226   octet hswok_in[MAXHASHSZ];            /* Inbound switch confirmation */
 227   octet hswrq_out[MAXHASHSZ];           /* Outbound switch request message */
 228   octet hswok_out[MAXHASHSZ];           /* Outbound switch confirmation */
 229 } kxchal;
 230
 231 typedef struct keyexch {
 232   struct peer *p;                       /* Pointer back to the peer */
 233   keyset **ks;                          /* Peer's list of keysets */
 234   unsigned f;                           /* Various useful flags */
 235   unsigned s;                           /* Current state in exchange */
 236   sel_timer t;                          /* Timer for next exchange */
 237   ge *kpub;                             /* Peer's public key */
 238   time_t texp_kpub;                     /* Expiry time for public key */
 239   mp *alpha;                            /* My temporary secret */
 240   ge *c;                                /* My challenge */
 241   ge *rx;                               /* The expected response */
 242   unsigned nr;                          /* Number of extant responses */
 243   time_t t_valid;                       /* When this exchange goes bad */
 244   octet hc[MAXHASHSZ];                  /* Hash of my challenge */
 245   kxchal *r[KX_NCHAL];                  /* Array of challenges */
 246 } keyexch;
 247
 248 #define KXF_TIMER 1u                    /* Waiting for a timer to go off */
 249 #define KXF_DEAD 2u                     /* The key-exchanger isn't up */
 250 #define KXF_PUBKEY 4u                   /* Key exchanger has a public key */
 251
 252 enum {
 253   KXS_DEAD,                             /* Uninitialized state (magical) */
 254   KXS_CHAL,                             /* Main answer-challenges state */
 255   KXS_COMMIT,                           /* Committed: send switch request */
 256   KXS_SWITCH                            /* Switched: send confirmation */
 257 };
 258
 259 /* --- Tunnel structure --- *
 260  *
 261  * Used to maintain system-specific information about the tunnel interface.
 262  */
 263
 264 typedef struct tunnel tunnel;
 265 struct peer;
 266
 267 typedef struct tunnel_ops {
 268   const char *name;                     /* Name of this tunnel driver */
 269   void (*init)(void);                   /* Initializes the system */
 270   tunnel *(*create)(struct peer */*p*/); /* Initializes a new tunnel */
 271   const char *(*ifname)(tunnel */*t*/); /* Returns tunnel's interface name */
 272   void (*inject)(tunnel */*t*/, buf */*b*/); /* Sends packet through if */
 273   void (*destroy)(tunnel */*t*/);       /* Destroys a tunnel */
 274 } tunnel_ops;
 275
 276 #ifndef TUN_INTERNALS
 277 struct tunnel { const tunnel_ops *ops; };
 278 #endif
 279
 280 /* --- Peer statistics --- *
 281  *
 282  * Contains various interesting and not-so-interesting statistics about a
 283  * peer.  This is updated by various parts of the code.  The format of the
 284  * structure isn't considered private, and @p_stats@ returns a pointer to the
 285  * statistics block for a given peer.
 286  */
 287
 288 typedef struct stats {
 289   unsigned long sz_in, sz_out;          /* Size of all data in and out */
 290   unsigned long sz_kxin, sz_kxout;      /* Size of key exchange messages */
 291   unsigned long sz_ipin, sz_ipout;      /* Size of encapsulated IP packets */
 292   time_t t_start, t_last, t_kx;         /* Time peer created, last pk, kx */
 293   unsigned long n_reject;               /* Number of rejected packets */
 294   unsigned long n_in, n_out;            /* Number of packets in and out */
 295   unsigned long n_kxin, n_kxout;        /* Number of key exchange packets */
 296   unsigned long n_ipin, n_ipout;        /* Number of encrypted packets */
 297 } stats;
 298
 299 /* --- Peer structure --- *
 300  *
 301  * The main structure which glues everything else together.
 302  */
 303
 304 typedef struct peerspec {
 305   char *name;                           /* Peer's name */
 306   const tunnel_ops *tops;               /* Tunnel operations */
 307   unsigned long t_ka;                   /* Keep alive interval */
 308   addr sa;                              /* Socket address to speak to */
 309   size_t sasz;                          /* Socket address size */
 310 } peerspec;
 311
 312 typedef struct peer {
 313   struct peer *next, *prev;             /* Links to next and previous */
 314   struct ping *pings;                   /* Pings we're waiting for */
 315   peerspec spec;                        /* Specifications for this peer */
 316   tunnel *t;                            /* Tunnel for local packets */
 317   char *ifname;                         /* Interface name for tunnel */
 318   keyset *ks;                           /* List head for keysets */
 319   buf b;                                /* Buffer for sending packets */
 320   stats st;                             /* Statistics */
 321   keyexch kx;                           /* Key exchange protocol block */
 322   sel_timer tka;                        /* Timer for keepalives */
 323 } peer;
 324
 325 typedef struct ping {
 326   struct ping *next, *prev;             /* Links to next and previous */
 327   peer *p;                              /* Peer so we can free it */
 328   unsigned msg;                         /* Kind of response expected */
 329   uint32 id;                            /* Id so we can recognize response */
 330   octet magic[32];                      /* Some random data */
 331   sel_timer t;                          /* Timeout for ping */
 332   void (*func)(int /*rc*/, void */*arg*/); /* Function to call when done */
 333   void *arg;                            /* Argument for callback */
 334 } ping;
 335
 336 enum {
 337   PING_NONOTIFY = -1,
 338   PING_OK = 0,
 339   PING_TIMEOUT,
 340   PING_PEERDIED,
 341   PING_MAX
 342 };
 343
 344 /* --- Admin structure --- */
 345
 346 #define OBUFSZ 16384u
 347
 348 typedef struct obuf {
 349   struct obuf *next;                    /* Next buffer in list */
 350   char *p_in, *p_out;                   /* Pointers into the buffer */
 351   char buf[OBUFSZ];                     /* The actual buffer */
 352 } obuf;
 353
 354 typedef struct oqueue {
 355   obuf *hd, *tl;                        /* Head and tail pointers */
 356 } oqueue;
 357
 358 struct admin;
 359
 360 typedef struct admin_bgop {
 361   struct admin_bgop *next, *prev;       /* Links to next and previous */
 362   struct admin *a;                      /* Owner job */
 363   char *tag;                            /* Tag string for messages */
 364   void (*cancel)(struct admin_bgop *);  /* Destructor function */
 365 } admin_bgop;
 366
 367 typedef struct admin_resop {
 368   admin_bgop bg;                        /* Background operation header */
 369   char *addr;                           /* Hostname to be resolved */
 370   bres_client r;                        /* Background resolver task */
 371   sel_timer t;                          /* Timer for resolver */
 372   addr sa;                              /* Socket address */
 373   size_t sasz;                          /* Socket address size */
 374   void (*func)(struct admin_resop *, int); /* Handler */
 375 } admin_resop;
 376
 377 enum { ARES_OK, ARES_FAIL };
 378
 379 typedef struct admin_addop {
 380   admin_resop r;                        /* Name resolution header */
 381   peerspec peer;                        /* Peer pending creation */
 382 } admin_addop;
 383
 384 typedef struct admin_greetop {
 385   admin_resop r;                        /* Name resolution header */
 386   void *c;                              /* Challenge block */
 387   size_t sz;                            /* Length of challenge */
 388 } admin_greetop;
 389
 390 typedef struct admin_pingop {
 391   admin_bgop bg;                        /* Background operation header */
 392   ping ping;                            /* Ping pending response */
 393   struct timeval pingtime;              /* Time last ping was sent */
 394 } admin_pingop;
 395
 396 typedef struct admin {
 397   struct admin *next, *prev;            /* Links to next and previous */
 398   unsigned f;                           /* Various useful flags */
 399   unsigned ref;                         /* Reference counter */
 400 #ifndef NTRACE
 401   unsigned seq;                         /* Sequence number for tracing */
 402 #endif
 403   oqueue out;                           /* Output buffer list */
 404   oqueue delay;                         /* Delayed output buffer list */
 405   admin_bgop *bg;                       /* Backgrounded operations */
 406   selbuf b;                             /* Line buffer for commands */
 407   sel_file w;                           /* Selector for write buffering */
 408 } admin;
 409
 410 #define AF_DEAD 1u                      /* Destroy this admin block */
 411 #define AF_CLOSE 2u                     /* Client closed connection */
 412 #define AF_NOTE 4u                      /* Catch notifications */
 413 #define AF_WARN 8u                      /* Catch warning messages */
 414 #ifndef NTRACE
 415   #define AF_TRACE 16u                  /* Catch tracing */
 416 #endif
 417
 418 #ifndef NTRACE
 419 #  define AF_ALLMSGS (AF_NOTE | AF_TRACE | AF_WARN)
 420 #else
 421 #  define AF_ALLMSGS (AF_NOTE | AF_WARN)
 422 #endif
 423
 424 /*----- Global variables --------------------------------------------------*/
 425
 426 extern sel_state sel;                   /* Global I/O event state */
 427 extern group *gg;                       /* The group we work in */
 428 extern size_t indexsz;                  /* Size of exponent for the group */
 429 extern mp *kpriv;                       /* Our private key */
 430 extern ge *kpub;                        /* Our public key */
 431 extern octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ];
 432 extern const tunnel_ops *tunnels[];     /* Table of tunnels (0-term) */
 433 extern const tunnel_ops *tun_default;   /* Default tunnel to use */
 434
 435 #ifndef NTRACE
 436 extern const trace_opt tr_opts[];       /* Trace options array */
 437 extern unsigned tr_flags;               /* Trace options flags */
 438 #endif
 439
 440 /*----- Other macros ------------------------------------------------------*/
 441
 442 #define TIMER noise_timer(RAND_GLOBAL)
 443
 444 /*----- Key management ----------------------------------------------------*/
 445
 446 /* --- @km_reload@ --- *
 447  *
 448  * Arguments:   ---
 449  *
 450  * Returns:     Zero if OK, nonzero to force reloading of keys.
 451  *
 452  * Use:         Checks the keyrings to see if they need reloading.
 453  */
 454
 455 extern int km_reload(void);
 456
 457 /* --- @km_init@ --- *
 458  *
 459  * Arguments:   @const char *kr_priv@ = private keyring file
 460  *              @const char *kr_pub@ = public keyring file
 461  *              @const char *tag@ = tag to load
 462  *
 463  * Returns:     ---
 464  *
 465  * Use:         Initializes, and loads the private key.
 466  */
 467
 468 extern void km_init(const char */*kr_priv*/, const char */*kr_pub*/,
 469                     const char */*tag*/);
 470
 471 /* --- @km_getpubkey@ --- *
 472  *
 473  * Arguments:   @const char *tag@ = public key tag to load
 474  *              @ge *kpub@ = where to put the public key
 475  *              @time_t *t_exp@ = where to put the expiry time
 476  *
 477  * Returns:     Zero if OK, nonzero if it failed.
 478  *
 479  * Use:         Fetches a public key from the keyring.
 480  */
 481
 482 extern int km_getpubkey(const char */*tag*/, ge */*kpub*/,
 483                         time_t */*t_exp*/);
 484
 485 /*----- Key exchange ------------------------------------------------------*/
 486
 487 /* --- @kx_start@ --- *
 488  *
 489  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 490  *              @int forcep@ = nonzero to ignore the quiet timer
 491  *
 492  * Returns:     ---
 493  *
 494  * Use:         Stimulates a key exchange.  If a key exchage is in progress,
 495  *              a new challenge is sent (unless the quiet timer forbids
 496  *              this); if no exchange is in progress, one is commenced.
 497  */
 498
 499 extern void kx_start(keyexch */*kx*/, int /*forcep*/);
 500
 501 /* --- @kx_message@ --- *
 502  *
 503  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 504  *              @unsigned msg@ = the message code
 505  *              @buf *b@ = pointer to buffer containing the packet
 506  *
 507  * Returns:     ---
 508  *
 509  * Use:         Reads a packet containing key exchange messages and handles
 510  *              it.
 511  */
 512
 513 extern void kx_message(keyexch */*kx*/, unsigned /*msg*/, buf */*b*/);
 514
 515 /* --- @kx_free@ --- *
 516  *
 517  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 518  *
 519  * Returns:     ---
 520  *
 521  * Use:         Frees everything in a key exchange context.
 522  */
 523
 524 extern void kx_free(keyexch */*kx*/);
 525
 526 /* --- @kx_newkeys@ --- *
 527  *
 528  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 529  *
 530  * Returns:     ---
 531  *
 532  * Use:         Informs the key exchange module that its keys may have
 533  *              changed.  If fetching the new keys fails, the peer will be
 534  *              destroyed, we log messages and struggle along with the old
 535  *              keys.
 536  */
 537
 538 extern void kx_newkeys(keyexch */*kx*/);
 539
 540 /* --- @kx_init@ --- *
 541  *
 542  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 543  *              @peer *p@ = pointer to peer context
 544  *              @keyset **ks@ = pointer to keyset list
 545  *
 546  * Returns:     Zero if OK, nonzero if it failed.
 547  *
 548  * Use:         Initializes a key exchange module.  The module currently
 549  *              contains no keys, and will attempt to initiate a key
 550  *              exchange.
 551  */
 552
 553 extern int kx_init(keyexch */*kx*/, peer */*p*/, keyset **/*ks*/);
 554
 555 /*----- Keysets and symmetric cryptography --------------------------------*/
 556
 557 /* --- @ks_drop@ --- *
 558  *
 559  * Arguments:   @keyset *ks@ = pointer to a keyset
 560  *
 561  * Returns:     ---
 562  *
 563  * Use:         Decrements a keyset's reference counter.  If the counter hits
 564  *              zero, the keyset is freed.
 565  */
 566
 567 extern void ks_drop(keyset */*ks*/);
 568
 569 /* --- @ks_gen@ --- *
 570  *
 571  * Arguments:   @const void *k@ = pointer to key material
 572  *              @size_t x, y, z@ = offsets into key material (see below)
 573  *              @peer *p@ = pointer to peer information
 574  *
 575  * Returns:     A pointer to the new keyset.
 576  *
 577  * Use:         Derives a new keyset from the given key material.  The
 578  *              offsets @x@, @y@ and @z@ separate the key material into three
 579  *              parts.  Between the @k@ and @k + x@ is `my' contribution to
 580  *              the key material; between @k + x@ and @k + y@ is `your'
 581  *              contribution; and between @k + y@ and @k + z@ is a shared
 582  *              value we made together.  These are used to construct two
 583  *              pairs of symmetric keys.  Each pair consists of an encryption
 584  *              key and a message authentication key.  One pair is used for
 585  *              outgoing messages, the other for incoming messages.
 586  *
 587  *              The new key is marked so that it won't be selected for output
 588  *              by @ksl_encrypt@.  You can still encrypt data with it by
 589  *              calling @ks_encrypt@ directly.
 590  */
 591
 592 extern keyset *ks_gen(const void */*k*/,
 593                       size_t /*x*/, size_t /*y*/, size_t /*z*/,
 594                       peer */*p*/);
 595
 596 /* --- @ks_tregen@ --- *
 597  *
 598  * Arguments:   @keyset *ks@ = pointer to a keyset
 599  *
 600  * Returns:     The time at which moves ought to be made to replace this key.
 601  */
 602
 603 extern time_t ks_tregen(keyset */*ks*/);
 604
 605 /* --- @ks_activate@ --- *
 606  *
 607  * Arguments:   @keyset *ks@ = pointer to a keyset
 608  *
 609  * Returns:     ---
 610  *
 611  * Use:         Activates a keyset, so that it can be used for encrypting
 612  *              outgoing messages.
 613  */
 614
 615 extern void ks_activate(keyset */*ks*/);
 616
 617 /* --- @ks_encrypt@ --- *
 618  *
 619  * Arguments:   @keyset *ks@ = pointer to a keyset
 620  *              @unsigned ty@ = message type
 621  *              @buf *b@ = pointer to input buffer
 622  *              @buf *bb@ = pointer to output buffer
 623  *
 624  * Returns:     Zero if OK, nonzero if the key needs replacing.  If the
 625  *              encryption failed, the output buffer is broken and zero is
 626  *              returned.
 627  *
 628  * Use:         Encrypts a block of data using the key.  Note that the `key
 629  *              ought to be replaced' notification is only ever given once
 630  *              for each key.  Also note that this call forces a keyset to be
 631  *              used even if it's marked as not for data output.
 632  */
 633
 634 extern int ks_encrypt(keyset */*ks*/, unsigned /*ty*/,
 635                       buf */*b*/, buf */*bb*/);
 636
 637 /* --- @ks_decrypt@ --- *
 638  *
 639  * Arguments:   @keyset *ks@ = pointer to a keyset
 640  *              @unsigned ty@ = expected type code
 641  *              @buf *b@ = pointer to an input buffer
 642  *              @buf *bb@ = pointer to an output buffer
 643  *
 644  * Returns:     Zero on success, or nonzero if there was some problem.
 645  *
 646  * Use:         Attempts to decrypt a message using a given key.  Note that
 647  *              requesting decryption with a key directly won't clear a
 648  *              marking that it's not for encryption.
 649  */
 650
 651 extern int ks_decrypt(keyset */*ks*/, unsigned /*ty*/,
 652                       buf */*b*/, buf */*bb*/);
 653
 654 /* --- @ksl_free@ --- *
 655  *
 656  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 657  *
 658  * Returns:     ---
 659  *
 660  * Use:         Frees (releases references to) all of the keys in a keyset.
 661  */
 662
 663 extern void ksl_free(keyset **/*ksroot*/);
 664
 665 /* --- @ksl_link@ --- *
 666  *
 667  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 668  *              @keyset *ks@ = pointer to a keyset
 669  *
 670  * Returns:     ---
 671  *
 672  * Use:         Links a keyset into a list.  A keyset can only be on one list
 673  *              at a time.  Bad things happen otherwise.
 674  */
 675
 676 extern void ksl_link(keyset **/*ksroot*/, keyset */*ks*/);
 677
 678 /* --- @ksl_prune@ --- *
 679  *
 680  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 681  *
 682  * Returns:     ---
 683  *
 684  * Use:         Prunes the keyset list by removing keys which mustn't be used
 685  *              any more.
 686  */
 687
 688 extern void ksl_prune(keyset **/*ksroot*/);
 689
 690 /* --- @ksl_encrypt@ --- *
 691  *
 692  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 693  *              @unsigned ty@ = message type
 694  *              @buf *b@ = pointer to input buffer
 695  *              @buf *bb@ = pointer to output buffer
 696  *
 697  * Returns:     Nonzero if a new key is needed.
 698  *
 699  * Use:         Encrypts a packet.
 700  */
 701
 702 extern int ksl_encrypt(keyset **/*ksroot*/, unsigned /*ty*/,
 703                        buf */*b*/, buf */*bb*/);
 704
 705 /* --- @ksl_decrypt@ --- *
 706  *
 707  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 708  *              @unsigned ty@ = expected type code
 709  *              @buf *b@ = pointer to input buffer
 710  *              @buf *bb@ = pointer to output buffer
 711  *
 712  * Returns:     Nonzero if the packet couldn't be decrypted.
 713  *
 714  * Use:         Decrypts a packet.
 715  */
 716
 717 extern int ksl_decrypt(keyset **/*ksroot*/, unsigned /*ty*/,
 718                        buf */*b*/, buf */*bb*/);
 719
 720 /*----- Challenges --------------------------------------------------------*/
 721
 722 /* --- @c_new@ --- *
 723  *
 724  * Arguments:   @buf *b@ = where to put the challenge
 725  *
 726  * Returns:     Zero if OK, nonzero on error.
 727  *
 728  * Use:         Issues a new challenge.
 729  */
 730
 731 extern int c_new(buf */*b*/);
 732
 733 /* --- @c_check@ --- *
 734  *
 735  * Arguments:   @buf *b@ = where to find the challenge
 736  *
 737  * Returns:     Zero if OK, nonzero if it didn't work.
 738  *
 739  * Use:         Checks a challenge.  On failure, the buffer is broken.
 740  */
 741
 742 extern int c_check(buf */*b*/);
 743
 744 /*----- Administration interface ------------------------------------------*/
 745
 746 #define A_END ((char *)0)
 747
 748 /* --- @a_warn@ --- *
 749  *
 750  * Arguments:   @const char *fmt@ = pointer to format string
 751  *              @...@ = other arguments
 752  *
 753  * Returns:     ---
 754  *
 755  * Use:         Informs all admin connections of a warning.
 756  */
 757
 758 extern void a_warn(const char */*fmt*/, ...);
 759
 760 /* --- @a_notify@ --- *
 761  *
 762  * Arguments:   @const char *fmt@ = pointer to format string
 763  *              @...@ = other arguments
 764  *
 765  * Returns:     ---
 766  *
 767  * Use:         Sends a notification to interested admin connections.
 768  */
 769
 770 extern void a_notify(const char */*fmt*/, ...);
 771
 772 /* --- @a_create@ --- *
 773  *
 774  * Arguments:   @int fd_in, fd_out@ = file descriptors to use
 775  *              @unsigned f@ = initial flags to set
 776  *
 777  * Returns:     ---
 778  *
 779  * Use:         Creates a new admin connection.
 780  */
 781
 782 extern void a_create(int /*fd_in*/, int /*fd_out*/, unsigned /*f*/);
 783
 784 /* --- @a_quit@ --- *
 785  *
 786  * Arguments:   ---
 787  *
 788  * Returns:     ---
 789  *
 790  * Use:         Shuts things down nicely.
 791  */
 792
 793 extern void a_quit(void);
 794
 795 /* --- @a_preselect@ --- *
 796  *
 797  * Arguments:   ---
 798  *
 799  * Returns:     ---
 800  *
 801  * Use:         Informs the admin module that we're about to select again,
 802  *              and that it should do cleanup things it has delayed until a
 803  *              `safe' time.
 804  */
 805
 806 extern void a_preselect(void);
 807
 808 /* --- @a_daemon@ --- *
 809  *
 810  * Arguments:   ---
 811  *
 812  * Returns:     ---
 813  *
 814  * Use:         Informs the admin module that it's a daemon.
 815  */
 816
 817 extern void a_daemon(void);
 818
 819 /* --- @a_init@ --- *
 820  *
 821  * Arguments:   @const char *sock@ = socket name to create
 822  *
 823  * Returns:     ---
 824  *
 825  * Use:         Creates the admin listening socket.
 826  */
 827
 828 extern void a_init(const char */*sock*/);
 829
 830 /*----- Peer management ---------------------------------------------------*/
 831
 832 /* --- @p_txstart@ --- *
 833  *
 834  * Arguments:   @peer *p@ = pointer to peer block
 835  *              @unsigned msg@ = message type code
 836  *
 837  * Returns:     A pointer to a buffer to write to.
 838  *
 839  * Use:         Starts sending to a peer.  Only one send can happen at a
 840  *              time.
 841  */
 842
 843 extern buf *p_txstart(peer */*p*/, unsigned /*msg*/);
 844
 845 /* --- @p_txend@ --- *
 846  *
 847  * Arguments:   @peer *p@ = pointer to peer block
 848  *
 849  * Returns:     ---
 850  *
 851  * Use:         Sends a packet to the peer.
 852  */
 853
 854 extern void p_txend(peer */*p*/);
 855
 856 /* --- @p_pingsend@ --- *
 857  *
 858  * Arguments:   @peer *p@ = destination peer
 859  *              @ping *pg@ = structure to fill in
 860  *              @unsigned type@ = message type
 861  *              @unsigned long timeout@ = how long to wait before giving up
 862  *              @void (*func)(int, void *)@ = callback function
 863  *              @void *arg@ = argument for callback
 864  *
 865  * Returns:     Zero if successful, nonzero if it failed.
 866  *
 867  * Use:         Sends a ping to a peer.  Call @func@ with a nonzero argument
 868  *              if we get an answer within the timeout, or zero if no answer.
 869  */
 870
 871 extern int p_pingsend(peer */*p*/, ping */*pg*/, unsigned /*type*/,
 872                       unsigned long /*timeout*/,
 873                       void (*/*func*/)(int, void *), void */*arg*/);
 874
 875 /* --- @p_pingdone@ --- *
 876  *
 877  * Arguments:   @ping *p@ = ping structure
 878  *              @int rc@ = return code to pass on
 879  *
 880  * Returns:     ---
 881  *
 882  * Use:         Disposes of a ping structure, maybe sending a notification.
 883  */
 884
 885 extern void p_pingdone(ping */*p*/, int /*rc*/);
 886
 887 /* --- @p_greet@ --- *
 888  *
 889  * Arguments:   @peer *p@ = peer to send to
 890  *              @const void *c@ = pointer to challenge
 891  *              @size_t sz@ = size of challenge
 892  *
 893  * Returns:     ---
 894  *
 895  * Use:         Sends a greeting packet.
 896  */
 897
 898 extern void p_greet(peer */*p*/, const void */*c*/, size_t /*sz*/);
 899
 900 /* --- @p_tun@ --- *
 901  *
 902  * Arguments:   @peer *p@ = pointer to peer block
 903  *              @buf *b@ = buffer containing incoming packet
 904  *
 905  * Returns:     ---
 906  *
 907  * Use:         Handles a packet which needs to be sent to a peer.
 908  */
 909
 910 extern void p_tun(peer */*p*/, buf */*b*/);
 911
 912 /* --- @p_keyreload@ --- *
 913  *
 914  * Arguments:   ---
 915  *
 916  * Returns:     ---
 917  *
 918  * Use:         Forces a check of the daemon's keyring files.
 919  */
 920
 921 extern void p_keyreload(void);
 922
 923 /* --- @p_interval@ --- *
 924  *
 925  * Arguments:   ---
 926  *
 927  * Returns:     ---
 928  *
 929  * Use:         Called periodically to do tidying.
 930  */
 931
 932 extern void p_interval(void);
 933
 934 /* --- @p_stats@ --- *
 935  *
 936  * Arguments:   @peer *p@ = pointer to a peer block
 937  *
 938  * Returns:     A pointer to the peer's statistics.
 939  */
 940
 941 extern stats *p_stats(peer */*p*/);
 942
 943 /* --- @p_ifname@ --- *
 944  *
 945  * Arguments:   @peer *p@ = pointer to a peer block
 946  *
 947  * Returns:     A pointer to the peer's interface name.
 948  */
 949
 950 extern const char *p_ifname(peer */*p*/);
 951
 952 /* --- @p_setifname@ --- *
 953  *
 954  * Arguments:   @peer *p@ = pointer to a peer block
 955  *              @const char *name@ = pointer to the new name
 956  *
 957  * Returns:     ---
 958  *
 959  * Use:         Changes the name held for a peer's interface.
 960  */
 961
 962 extern void p_setifname(peer */*p*/, const char */*name*/);
 963
 964 /* --- @p_addr@ --- *
 965  *
 966  * Arguments:   @peer *p@ = pointer to a peer block
 967  *
 968  * Returns:     A pointer to the peer's address.
 969  */
 970
 971 extern const addr *p_addr(peer */*p*/);
 972
 973 /* --- @p_init@ --- *
 974  *
 975  * Arguments:   @struct in_addr addr@ = address to bind to
 976  *              @unsigned port@ = port number to listen to
 977  *
 978  * Returns:     ---
 979  *
 980  * Use:         Initializes the peer system; creates the socket.
 981  */
 982
 983 extern void p_init(struct in_addr /*addr*/, unsigned /*port*/);
 984
 985 /* --- @p_port@ --- *
 986  *
 987  * Arguments:   ---
 988  *
 989  * Returns:     Port number used for socket.
 990  */
 991
 992 unsigned p_port(void);
 993
 994 /* --- @p_create@ --- *
 995  *
 996  * Arguments:   @peerspec *spec@ = information about this peer
 997  *
 998  * Returns:     Pointer to the peer block, or null if it failed.
 999  *
1000  * Use:         Creates a new named peer block.  No peer is actually attached
1001  *              by this point.
1002  */
1003
1004 extern peer *p_create(peerspec */*spec*/);
1005
1006 /* --- @p_name@ --- *
1007  *
1008  * Arguments:   @peer *p@ = pointer to a peer block
1009  *
1010  * Returns:     A pointer to the peer's name.
1011  *
1012  * Use:         Equivalent to @p_spec(p)->name@.
1013  */
1014
1015 extern const char *p_name(peer */*p*/);
1016
1017 /* --- @p_spec@ --- *
1018  *
1019  * Arguments:   @peer *p@ = pointer to a peer block
1020  *
1021  * Returns:     Pointer to the peer's specification
1022  */
1023
1024 extern const peerspec *p_spec(peer */*p*/);
1025
1026 /* --- @p_find@ --- *
1027  *
1028  * Arguments:   @const char *name@ = name to look up
1029  *
1030  * Returns:     Pointer to the peer block, or null if not found.
1031  *
1032  * Use:         Finds a peer by name.
1033  */
1034
1035 extern peer *p_find(const char */*name*/);
1036
1037 /* --- @p_destroy@ --- *
1038  *
1039  * Arguments:   @peer *p@ = pointer to a peer
1040  *
1041  * Returns:     ---
1042  *
1043  * Use:         Destroys a peer.
1044  */
1045
1046 extern void p_destroy(peer */*p*/);
1047
1048 /* --- @p_first@, @p_next@ --- *
1049  *
1050  * Arguments:   @peer *p@ = a peer block
1051  *
1052  * Returns:     @peer_first@ returns the first peer in some ordering;
1053  *              @peer_next@ returns the peer following a given one in the
1054  *              same ordering.  Null is returned for the end of the list.
1055  */
1056
1057 extern peer *p_first(void);
1058 extern peer *p_next(peer */*p*/);
1059
1060 /*----- Tunnel drivers ----------------------------------------------------*/
1061
1062 #ifdef TUN_LINUX
1063   extern const tunnel_ops tun_linux;
1064 #endif
1065
1066 #ifdef TUN_UNET
1067   extern const tunnel_ops tun_unet;
1068 #endif
1069
1070 #ifdef TUN_BSD
1071   extern const tunnel_ops tun_bsd;
1072 #endif
1073
1074 extern const tunnel_ops tun_slip;
1075
1076 /*----- Other handy utilities ---------------------------------------------*/
1077
1078 /* --- @mpstr@ --- *
1079  *
1080  * Arguments:   @mp *m@ = a multiprecision integer
1081  *
1082  * Returns:     A pointer to the integer's textual representation.
1083  *
1084  * Use:         Converts a multiprecision integer to a string.  Corrupts
1085  *              @buf_t@.
1086  */
1087
1088 extern const char *mpstr(mp */*m*/);
1089
1090 /* --- @gestr@ --- *
1091  *
1092  * Arguments:   @group *g@ = a group
1093  *              @ge *x@ = a group element
1094  *
1095  * Returns:     A pointer to the element's textual representation.
1096  *
1097  * Use:         Converts a group element to a string.  Corrupts
1098  *              @buf_t@.
1099  */
1100
1101 extern const char *gestr(group */*g*/, ge */*x*/);
1102
1103 /* --- @timestr@ --- *
1104  *
1105  * Arguments:   @time_t t@ = a time to convert
1106  *
1107  * Returns:     A pointer to a textual representation of the time.
1108  *
1109  * Use:         Converts a time to a textual representation.  Corrupts
1110  *              @buf_t@.
1111  */
1112
1113 extern const char *timestr(time_t /*t*/);
1114
1115 /* --- @mystrieq@ --- *
1116  *
1117  * Arguments:   @const char *x, *y@ = two strings
1118  *
1119  * Returns:     True if @x@ and @y are equal, up to case.
1120  */
1121
1122 extern int mystrieq(const char */*x*/, const char */*y*/);
1123
1124 /* --- @seq_reset@ --- *
1125  *
1126  * Arguments:   @seqwin *s@ = sequence-checking window
1127  *
1128  * Returns:     ---
1129  *
1130  * Use:         Resets a sequence number window.
1131  */
1132
1133 extern void seq_reset(seqwin */*s*/);
1134
1135 /* --- @seq_check@ --- *
1136  *
1137  * Arguments:   @seqwin *s@ = sequence-checking window
1138  *              @uint32 q@ = sequence number to check
1139  *              @const char *service@ = service to report message from
1140  *
1141  * Returns:     A @SEQ_@ code.
1142  *
1143  * Use:         Checks a sequence number against the window, updating things
1144  *              as necessary.
1145  */
1146
1147 extern int seq_check(seqwin */*s*/, uint32 /*q*/, const char */*service*/);
1148
1149 /* --- @versioncmp@ --- *
1150  *
1151  * Arguments:   @const char *va, *vb@ = two version strings
1152  *
1153  * Returns:     Less than, equal to, or greater than zero, according to
1154  *              whether @va@ is less than, equal to, or greater than @vb@.
1155  *
1156  * Use:         Compares version number strings.
1157  *
1158  *              The algorithm is an extension of the Debian version
1159  *              comparison algorithm.  A version number consists of three
1160  *              components:
1161  *
1162  *                [EPOCH :] MAIN [- SUB]
1163  *
1164  *              The MAIN part may contain colons or hyphens if there is an
1165  *              EPOCH or SUB, respectively.  Version strings are compared
1166  *              componentwise: first epochs, then main parts, and finally
1167  *              subparts.
1168  *
1169  *              The component comparison is done as follows.  First, the
1170  *              initial subsequence of nondigit characters is extracted from
1171  *              each string, and these are compared lexicographically, using
1172  *              ASCII ordering, except that letters precede non-letters.  If
1173  *              both are the same, an initial sequence of digits is extracted
1174  *              from the remaining parts of the version strings, and these
1175  *              are compared numerically (an empty sequence being considered
1176  *              to have the value zero).  This process is repeated until we
1177  *              have a winner or until both strings are exhausted.
1178  */
1179
1180 extern int versioncmp(const char */*va*/, const char */*vb*/);
1181
1182 /*----- That's all, folks -------------------------------------------------*/
1183
1184 #ifdef __cplusplus
1185   }
1186 #endif
1187
1188 #endif