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_service {
 397   sym_base _b;                          /* Hash table base structure */
 398   char *version;                        /* The provided version */
 399   struct admin *prov;                   /* Which client provides me */
 400   struct admin_service *next, *prev;    /* Client's list of services */
 401 } admin_service;
 402
 403 typedef struct admin_svcop {
 404   admin_bgop bg;                        /* Background operation header */
 405   struct admin *prov;                   /* Client servicing this job */
 406   unsigned short index;                 /* This job's index */
 407   struct admin_svcop *next, *prev;      /* Links for provider's jobs */
 408 } admin_svcop;
 409
 410 typedef struct admin_jobentry {
 411   unsigned short seq;                   /* Zero if unused */
 412   union {
 413     admin_svcop *op;                    /* Operation, if slot in use, ... */
 414     uint32 next;                        /* ... or index of next free slot */
 415   } u;
 416 } admin_jobentry;
 417
 418 typedef struct admin_jobtable {
 419   uint32 n, sz;                         /* Used slots and table size */
 420   admin_svcop *active;                  /* List of active jobs */
 421   uint32 free;                          /* Index of first free slot */
 422   admin_jobentry *v;                    /* And the big array of entries */
 423 } admin_jobtable;
 424
 425 typedef struct admin {
 426   struct admin *next, *prev;            /* Links to next and previous */
 427   unsigned f;                           /* Various useful flags */
 428   unsigned ref;                         /* Reference counter */
 429 #ifndef NTRACE
 430   unsigned seq;                         /* Sequence number for tracing */
 431 #endif
 432   oqueue out;                           /* Output buffer list */
 433   oqueue delay;                         /* Delayed output buffer list */
 434   admin_bgop *bg;                       /* Backgrounded operations */
 435   admin_service *svcs;                  /* Which services I provide */
 436   admin_jobtable j;                     /* Table of outstanding jobs */
 437   selbuf b;                             /* Line buffer for commands */
 438   sel_file w;                           /* Selector for write buffering */
 439 } admin;
 440
 441 #define AF_DEAD 1u                      /* Destroy this admin block */
 442 #define AF_CLOSE 2u                     /* Client closed connection */
 443 #define AF_NOTE 4u                      /* Catch notifications */
 444 #define AF_WARN 8u                      /* Catch warning messages */
 445 #ifndef NTRACE
 446   #define AF_TRACE 16u                  /* Catch tracing */
 447 #endif
 448
 449 #ifndef NTRACE
 450 #  define AF_ALLMSGS (AF_NOTE | AF_TRACE | AF_WARN)
 451 #else
 452 #  define AF_ALLMSGS (AF_NOTE | AF_WARN)
 453 #endif
 454
 455 /*----- Global variables --------------------------------------------------*/
 456
 457 extern sel_state sel;                   /* Global I/O event state */
 458 extern group *gg;                       /* The group we work in */
 459 extern size_t indexsz;                  /* Size of exponent for the group */
 460 extern mp *kpriv;                       /* Our private key */
 461 extern ge *kpub;                        /* Our public key */
 462 extern octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ];
 463 extern const tunnel_ops *tunnels[];     /* Table of tunnels (0-term) */
 464 extern const tunnel_ops *tun_default;   /* Default tunnel to use */
 465
 466 #ifndef NTRACE
 467 extern const trace_opt tr_opts[];       /* Trace options array */
 468 extern unsigned tr_flags;               /* Trace options flags */
 469 #endif
 470
 471 /*----- Other macros ------------------------------------------------------*/
 472
 473 #define TIMER noise_timer(RAND_GLOBAL)
 474
 475 /*----- Key management ----------------------------------------------------*/
 476
 477 /* --- @km_reload@ --- *
 478  *
 479  * Arguments:   ---
 480  *
 481  * Returns:     Zero if OK, nonzero to force reloading of keys.
 482  *
 483  * Use:         Checks the keyrings to see if they need reloading.
 484  */
 485
 486 extern int km_reload(void);
 487
 488 /* --- @km_init@ --- *
 489  *
 490  * Arguments:   @const char *kr_priv@ = private keyring file
 491  *              @const char *kr_pub@ = public keyring file
 492  *              @const char *tag@ = tag to load
 493  *
 494  * Returns:     ---
 495  *
 496  * Use:         Initializes, and loads the private key.
 497  */
 498
 499 extern void km_init(const char */*kr_priv*/, const char */*kr_pub*/,
 500                     const char */*tag*/);
 501
 502 /* --- @km_getpubkey@ --- *
 503  *
 504  * Arguments:   @const char *tag@ = public key tag to load
 505  *              @ge *kpub@ = where to put the public key
 506  *              @time_t *t_exp@ = where to put the expiry time
 507  *
 508  * Returns:     Zero if OK, nonzero if it failed.
 509  *
 510  * Use:         Fetches a public key from the keyring.
 511  */
 512
 513 extern int km_getpubkey(const char */*tag*/, ge */*kpub*/,
 514                         time_t */*t_exp*/);
 515
 516 /*----- Key exchange ------------------------------------------------------*/
 517
 518 /* --- @kx_start@ --- *
 519  *
 520  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 521  *              @int forcep@ = nonzero to ignore the quiet timer
 522  *
 523  * Returns:     ---
 524  *
 525  * Use:         Stimulates a key exchange.  If a key exchage is in progress,
 526  *              a new challenge is sent (unless the quiet timer forbids
 527  *              this); if no exchange is in progress, one is commenced.
 528  */
 529
 530 extern void kx_start(keyexch */*kx*/, int /*forcep*/);
 531
 532 /* --- @kx_message@ --- *
 533  *
 534  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 535  *              @unsigned msg@ = the message code
 536  *              @buf *b@ = pointer to buffer containing the packet
 537  *
 538  * Returns:     ---
 539  *
 540  * Use:         Reads a packet containing key exchange messages and handles
 541  *              it.
 542  */
 543
 544 extern void kx_message(keyexch */*kx*/, unsigned /*msg*/, buf */*b*/);
 545
 546 /* --- @kx_free@ --- *
 547  *
 548  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 549  *
 550  * Returns:     ---
 551  *
 552  * Use:         Frees everything in a key exchange context.
 553  */
 554
 555 extern void kx_free(keyexch */*kx*/);
 556
 557 /* --- @kx_newkeys@ --- *
 558  *
 559  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 560  *
 561  * Returns:     ---
 562  *
 563  * Use:         Informs the key exchange module that its keys may have
 564  *              changed.  If fetching the new keys fails, the peer will be
 565  *              destroyed, we log messages and struggle along with the old
 566  *              keys.
 567  */
 568
 569 extern void kx_newkeys(keyexch */*kx*/);
 570
 571 /* --- @kx_init@ --- *
 572  *
 573  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 574  *              @peer *p@ = pointer to peer context
 575  *              @keyset **ks@ = pointer to keyset list
 576  *
 577  * Returns:     Zero if OK, nonzero if it failed.
 578  *
 579  * Use:         Initializes a key exchange module.  The module currently
 580  *              contains no keys, and will attempt to initiate a key
 581  *              exchange.
 582  */
 583
 584 extern int kx_init(keyexch */*kx*/, peer */*p*/, keyset **/*ks*/);
 585
 586 /*----- Keysets and symmetric cryptography --------------------------------*/
 587
 588 /* --- @ks_drop@ --- *
 589  *
 590  * Arguments:   @keyset *ks@ = pointer to a keyset
 591  *
 592  * Returns:     ---
 593  *
 594  * Use:         Decrements a keyset's reference counter.  If the counter hits
 595  *              zero, the keyset is freed.
 596  */
 597
 598 extern void ks_drop(keyset */*ks*/);
 599
 600 /* --- @ks_gen@ --- *
 601  *
 602  * Arguments:   @const void *k@ = pointer to key material
 603  *              @size_t x, y, z@ = offsets into key material (see below)
 604  *              @peer *p@ = pointer to peer information
 605  *
 606  * Returns:     A pointer to the new keyset.
 607  *
 608  * Use:         Derives a new keyset from the given key material.  The
 609  *              offsets @x@, @y@ and @z@ separate the key material into three
 610  *              parts.  Between the @k@ and @k + x@ is `my' contribution to
 611  *              the key material; between @k + x@ and @k + y@ is `your'
 612  *              contribution; and between @k + y@ and @k + z@ is a shared
 613  *              value we made together.  These are used to construct two
 614  *              pairs of symmetric keys.  Each pair consists of an encryption
 615  *              key and a message authentication key.  One pair is used for
 616  *              outgoing messages, the other for incoming messages.
 617  *
 618  *              The new key is marked so that it won't be selected for output
 619  *              by @ksl_encrypt@.  You can still encrypt data with it by
 620  *              calling @ks_encrypt@ directly.
 621  */
 622
 623 extern keyset *ks_gen(const void */*k*/,
 624                       size_t /*x*/, size_t /*y*/, size_t /*z*/,
 625                       peer */*p*/);
 626
 627 /* --- @ks_tregen@ --- *
 628  *
 629  * Arguments:   @keyset *ks@ = pointer to a keyset
 630  *
 631  * Returns:     The time at which moves ought to be made to replace this key.
 632  */
 633
 634 extern time_t ks_tregen(keyset */*ks*/);
 635
 636 /* --- @ks_activate@ --- *
 637  *
 638  * Arguments:   @keyset *ks@ = pointer to a keyset
 639  *
 640  * Returns:     ---
 641  *
 642  * Use:         Activates a keyset, so that it can be used for encrypting
 643  *              outgoing messages.
 644  */
 645
 646 extern void ks_activate(keyset */*ks*/);
 647
 648 /* --- @ks_encrypt@ --- *
 649  *
 650  * Arguments:   @keyset *ks@ = pointer to a keyset
 651  *              @unsigned ty@ = message type
 652  *              @buf *b@ = pointer to input buffer
 653  *              @buf *bb@ = pointer to output buffer
 654  *
 655  * Returns:     Zero if OK, nonzero if the key needs replacing.  If the
 656  *              encryption failed, the output buffer is broken and zero is
 657  *              returned.
 658  *
 659  * Use:         Encrypts a block of data using the key.  Note that the `key
 660  *              ought to be replaced' notification is only ever given once
 661  *              for each key.  Also note that this call forces a keyset to be
 662  *              used even if it's marked as not for data output.
 663  */
 664
 665 extern int ks_encrypt(keyset */*ks*/, unsigned /*ty*/,
 666                       buf */*b*/, buf */*bb*/);
 667
 668 /* --- @ks_decrypt@ --- *
 669  *
 670  * Arguments:   @keyset *ks@ = pointer to a keyset
 671  *              @unsigned ty@ = expected type code
 672  *              @buf *b@ = pointer to an input buffer
 673  *              @buf *bb@ = pointer to an output buffer
 674  *
 675  * Returns:     Zero on success, or nonzero if there was some problem.
 676  *
 677  * Use:         Attempts to decrypt a message using a given key.  Note that
 678  *              requesting decryption with a key directly won't clear a
 679  *              marking that it's not for encryption.
 680  */
 681
 682 extern int ks_decrypt(keyset */*ks*/, unsigned /*ty*/,
 683                       buf */*b*/, buf */*bb*/);
 684
 685 /* --- @ksl_free@ --- *
 686  *
 687  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 688  *
 689  * Returns:     ---
 690  *
 691  * Use:         Frees (releases references to) all of the keys in a keyset.
 692  */
 693
 694 extern void ksl_free(keyset **/*ksroot*/);
 695
 696 /* --- @ksl_link@ --- *
 697  *
 698  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 699  *              @keyset *ks@ = pointer to a keyset
 700  *
 701  * Returns:     ---
 702  *
 703  * Use:         Links a keyset into a list.  A keyset can only be on one list
 704  *              at a time.  Bad things happen otherwise.
 705  */
 706
 707 extern void ksl_link(keyset **/*ksroot*/, keyset */*ks*/);
 708
 709 /* --- @ksl_prune@ --- *
 710  *
 711  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 712  *
 713  * Returns:     ---
 714  *
 715  * Use:         Prunes the keyset list by removing keys which mustn't be used
 716  *              any more.
 717  */
 718
 719 extern void ksl_prune(keyset **/*ksroot*/);
 720
 721 /* --- @ksl_encrypt@ --- *
 722  *
 723  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 724  *              @unsigned ty@ = message type
 725  *              @buf *b@ = pointer to input buffer
 726  *              @buf *bb@ = pointer to output buffer
 727  *
 728  * Returns:     Nonzero if a new key is needed.
 729  *
 730  * Use:         Encrypts a packet.
 731  */
 732
 733 extern int ksl_encrypt(keyset **/*ksroot*/, unsigned /*ty*/,
 734                        buf */*b*/, buf */*bb*/);
 735
 736 /* --- @ksl_decrypt@ --- *
 737  *
 738  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 739  *              @unsigned ty@ = expected type code
 740  *              @buf *b@ = pointer to input buffer
 741  *              @buf *bb@ = pointer to output buffer
 742  *
 743  * Returns:     Nonzero if the packet couldn't be decrypted.
 744  *
 745  * Use:         Decrypts a packet.
 746  */
 747
 748 extern int ksl_decrypt(keyset **/*ksroot*/, unsigned /*ty*/,
 749                        buf */*b*/, buf */*bb*/);
 750
 751 /*----- Challenges --------------------------------------------------------*/
 752
 753 /* --- @c_new@ --- *
 754  *
 755  * Arguments:   @buf *b@ = where to put the challenge
 756  *
 757  * Returns:     Zero if OK, nonzero on error.
 758  *
 759  * Use:         Issues a new challenge.
 760  */
 761
 762 extern int c_new(buf */*b*/);
 763
 764 /* --- @c_check@ --- *
 765  *
 766  * Arguments:   @buf *b@ = where to find the challenge
 767  *
 768  * Returns:     Zero if OK, nonzero if it didn't work.
 769  *
 770  * Use:         Checks a challenge.  On failure, the buffer is broken.
 771  */
 772
 773 extern int c_check(buf */*b*/);
 774
 775 /*----- Administration interface ------------------------------------------*/
 776
 777 #define A_END ((char *)0)
 778
 779 /* --- @a_warn@ --- *
 780  *
 781  * Arguments:   @const char *fmt@ = pointer to format string
 782  *              @...@ = other arguments
 783  *
 784  * Returns:     ---
 785  *
 786  * Use:         Informs all admin connections of a warning.
 787  */
 788
 789 extern void a_warn(const char */*fmt*/, ...);
 790
 791 /* --- @a_notify@ --- *
 792  *
 793  * Arguments:   @const char *fmt@ = pointer to format string
 794  *              @...@ = other arguments
 795  *
 796  * Returns:     ---
 797  *
 798  * Use:         Sends a notification to interested admin connections.
 799  */
 800
 801 extern void a_notify(const char */*fmt*/, ...);
 802
 803 /* --- @a_create@ --- *
 804  *
 805  * Arguments:   @int fd_in, fd_out@ = file descriptors to use
 806  *              @unsigned f@ = initial flags to set
 807  *
 808  * Returns:     ---
 809  *
 810  * Use:         Creates a new admin connection.
 811  */
 812
 813 extern void a_create(int /*fd_in*/, int /*fd_out*/, unsigned /*f*/);
 814
 815 /* --- @a_quit@ --- *
 816  *
 817  * Arguments:   ---
 818  *
 819  * Returns:     ---
 820  *
 821  * Use:         Shuts things down nicely.
 822  */
 823
 824 extern void a_quit(void);
 825
 826 /* --- @a_preselect@ --- *
 827  *
 828  * Arguments:   ---
 829  *
 830  * Returns:     ---
 831  *
 832  * Use:         Informs the admin module that we're about to select again,
 833  *              and that it should do cleanup things it has delayed until a
 834  *              `safe' time.
 835  */
 836
 837 extern void a_preselect(void);
 838
 839 /* --- @a_daemon@ --- *
 840  *
 841  * Arguments:   ---
 842  *
 843  * Returns:     ---
 844  *
 845  * Use:         Informs the admin module that it's a daemon.
 846  */
 847
 848 extern void a_daemon(void);
 849
 850 /* --- @a_init@ --- *
 851  *
 852  * Arguments:   @const char *sock@ = socket name to create
 853  *
 854  * Returns:     ---
 855  *
 856  * Use:         Creates the admin listening socket.
 857  */
 858
 859 extern void a_init(const char */*sock*/);
 860
 861 /*----- Peer management ---------------------------------------------------*/
 862
 863 /* --- @p_txstart@ --- *
 864  *
 865  * Arguments:   @peer *p@ = pointer to peer block
 866  *              @unsigned msg@ = message type code
 867  *
 868  * Returns:     A pointer to a buffer to write to.
 869  *
 870  * Use:         Starts sending to a peer.  Only one send can happen at a
 871  *              time.
 872  */
 873
 874 extern buf *p_txstart(peer */*p*/, unsigned /*msg*/);
 875
 876 /* --- @p_txend@ --- *
 877  *
 878  * Arguments:   @peer *p@ = pointer to peer block
 879  *
 880  * Returns:     ---
 881  *
 882  * Use:         Sends a packet to the peer.
 883  */
 884
 885 extern void p_txend(peer */*p*/);
 886
 887 /* --- @p_pingsend@ --- *
 888  *
 889  * Arguments:   @peer *p@ = destination peer
 890  *              @ping *pg@ = structure to fill in
 891  *              @unsigned type@ = message type
 892  *              @unsigned long timeout@ = how long to wait before giving up
 893  *              @void (*func)(int, void *)@ = callback function
 894  *              @void *arg@ = argument for callback
 895  *
 896  * Returns:     Zero if successful, nonzero if it failed.
 897  *
 898  * Use:         Sends a ping to a peer.  Call @func@ with a nonzero argument
 899  *              if we get an answer within the timeout, or zero if no answer.
 900  */
 901
 902 extern int p_pingsend(peer */*p*/, ping */*pg*/, unsigned /*type*/,
 903                       unsigned long /*timeout*/,
 904                       void (*/*func*/)(int, void *), void */*arg*/);
 905
 906 /* --- @p_pingdone@ --- *
 907  *
 908  * Arguments:   @ping *p@ = ping structure
 909  *              @int rc@ = return code to pass on
 910  *
 911  * Returns:     ---
 912  *
 913  * Use:         Disposes of a ping structure, maybe sending a notification.
 914  */
 915
 916 extern void p_pingdone(ping */*p*/, int /*rc*/);
 917
 918 /* --- @p_greet@ --- *
 919  *
 920  * Arguments:   @peer *p@ = peer to send to
 921  *              @const void *c@ = pointer to challenge
 922  *              @size_t sz@ = size of challenge
 923  *
 924  * Returns:     ---
 925  *
 926  * Use:         Sends a greeting packet.
 927  */
 928
 929 extern void p_greet(peer */*p*/, const void */*c*/, size_t /*sz*/);
 930
 931 /* --- @p_tun@ --- *
 932  *
 933  * Arguments:   @peer *p@ = pointer to peer block
 934  *              @buf *b@ = buffer containing incoming packet
 935  *
 936  * Returns:     ---
 937  *
 938  * Use:         Handles a packet which needs to be sent to a peer.
 939  */
 940
 941 extern void p_tun(peer */*p*/, buf */*b*/);
 942
 943 /* --- @p_keyreload@ --- *
 944  *
 945  * Arguments:   ---
 946  *
 947  * Returns:     ---
 948  *
 949  * Use:         Forces a check of the daemon's keyring files.
 950  */
 951
 952 extern void p_keyreload(void);
 953
 954 /* --- @p_interval@ --- *
 955  *
 956  * Arguments:   ---
 957  *
 958  * Returns:     ---
 959  *
 960  * Use:         Called periodically to do tidying.
 961  */
 962
 963 extern void p_interval(void);
 964
 965 /* --- @p_stats@ --- *
 966  *
 967  * Arguments:   @peer *p@ = pointer to a peer block
 968  *
 969  * Returns:     A pointer to the peer's statistics.
 970  */
 971
 972 extern stats *p_stats(peer */*p*/);
 973
 974 /* --- @p_ifname@ --- *
 975  *
 976  * Arguments:   @peer *p@ = pointer to a peer block
 977  *
 978  * Returns:     A pointer to the peer's interface name.
 979  */
 980
 981 extern const char *p_ifname(peer */*p*/);
 982
 983 /* --- @p_setifname@ --- *
 984  *
 985  * Arguments:   @peer *p@ = pointer to a peer block
 986  *              @const char *name@ = pointer to the new name
 987  *
 988  * Returns:     ---
 989  *
 990  * Use:         Changes the name held for a peer's interface.
 991  */
 992
 993 extern void p_setifname(peer */*p*/, const char */*name*/);
 994
 995 /* --- @p_addr@ --- *
 996  *
 997  * Arguments:   @peer *p@ = pointer to a peer block
 998  *
 999  * Returns:     A pointer to the peer's address.
1000  */
1001
1002 extern const addr *p_addr(peer */*p*/);
1003
1004 /* --- @p_init@ --- *
1005  *
1006  * Arguments:   @struct in_addr addr@ = address to bind to
1007  *              @unsigned port@ = port number to listen to
1008  *
1009  * Returns:     ---
1010  *
1011  * Use:         Initializes the peer system; creates the socket.
1012  */
1013
1014 extern void p_init(struct in_addr /*addr*/, unsigned /*port*/);
1015
1016 /* --- @p_port@ --- *
1017  *
1018  * Arguments:   ---
1019  *
1020  * Returns:     Port number used for socket.
1021  */
1022
1023 unsigned p_port(void);
1024
1025 /* --- @p_create@ --- *
1026  *
1027  * Arguments:   @peerspec *spec@ = information about this peer
1028  *
1029  * Returns:     Pointer to the peer block, or null if it failed.
1030  *
1031  * Use:         Creates a new named peer block.  No peer is actually attached
1032  *              by this point.
1033  */
1034
1035 extern peer *p_create(peerspec */*spec*/);
1036
1037 /* --- @p_name@ --- *
1038  *
1039  * Arguments:   @peer *p@ = pointer to a peer block
1040  *
1041  * Returns:     A pointer to the peer's name.
1042  *
1043  * Use:         Equivalent to @p_spec(p)->name@.
1044  */
1045
1046 extern const char *p_name(peer */*p*/);
1047
1048 /* --- @p_spec@ --- *
1049  *
1050  * Arguments:   @peer *p@ = pointer to a peer block
1051  *
1052  * Returns:     Pointer to the peer's specification
1053  */
1054
1055 extern const peerspec *p_spec(peer */*p*/);
1056
1057 /* --- @p_find@ --- *
1058  *
1059  * Arguments:   @const char *name@ = name to look up
1060  *
1061  * Returns:     Pointer to the peer block, or null if not found.
1062  *
1063  * Use:         Finds a peer by name.
1064  */
1065
1066 extern peer *p_find(const char */*name*/);
1067
1068 /* --- @p_destroy@ --- *
1069  *
1070  * Arguments:   @peer *p@ = pointer to a peer
1071  *
1072  * Returns:     ---
1073  *
1074  * Use:         Destroys a peer.
1075  */
1076
1077 extern void p_destroy(peer */*p*/);
1078
1079 /* --- @p_first@, @p_next@ --- *
1080  *
1081  * Arguments:   @peer *p@ = a peer block
1082  *
1083  * Returns:     @peer_first@ returns the first peer in some ordering;
1084  *              @peer_next@ returns the peer following a given one in the
1085  *              same ordering.  Null is returned for the end of the list.
1086  */
1087
1088 extern peer *p_first(void);
1089 extern peer *p_next(peer */*p*/);
1090
1091 /*----- Tunnel drivers ----------------------------------------------------*/
1092
1093 #ifdef TUN_LINUX
1094   extern const tunnel_ops tun_linux;
1095 #endif
1096
1097 #ifdef TUN_UNET
1098   extern const tunnel_ops tun_unet;
1099 #endif
1100
1101 #ifdef TUN_BSD
1102   extern const tunnel_ops tun_bsd;
1103 #endif
1104
1105 extern const tunnel_ops tun_slip;
1106
1107 /*----- Other handy utilities ---------------------------------------------*/
1108
1109 /* --- @mpstr@ --- *
1110  *
1111  * Arguments:   @mp *m@ = a multiprecision integer
1112  *
1113  * Returns:     A pointer to the integer's textual representation.
1114  *
1115  * Use:         Converts a multiprecision integer to a string.  Corrupts
1116  *              @buf_t@.
1117  */
1118
1119 extern const char *mpstr(mp */*m*/);
1120
1121 /* --- @gestr@ --- *
1122  *
1123  * Arguments:   @group *g@ = a group
1124  *              @ge *x@ = a group element
1125  *
1126  * Returns:     A pointer to the element's textual representation.
1127  *
1128  * Use:         Converts a group element to a string.  Corrupts
1129  *              @buf_t@.
1130  */
1131
1132 extern const char *gestr(group */*g*/, ge */*x*/);
1133
1134 /* --- @timestr@ --- *
1135  *
1136  * Arguments:   @time_t t@ = a time to convert
1137  *
1138  * Returns:     A pointer to a textual representation of the time.
1139  *
1140  * Use:         Converts a time to a textual representation.  Corrupts
1141  *              @buf_t@.
1142  */
1143
1144 extern const char *timestr(time_t /*t*/);
1145
1146 /* --- @mystrieq@ --- *
1147  *
1148  * Arguments:   @const char *x, *y@ = two strings
1149  *
1150  * Returns:     True if @x@ and @y are equal, up to case.
1151  */
1152
1153 extern int mystrieq(const char */*x*/, const char */*y*/);
1154
1155 /* --- @seq_reset@ --- *
1156  *
1157  * Arguments:   @seqwin *s@ = sequence-checking window
1158  *
1159  * Returns:     ---
1160  *
1161  * Use:         Resets a sequence number window.
1162  */
1163
1164 extern void seq_reset(seqwin */*s*/);
1165
1166 /* --- @seq_check@ --- *
1167  *
1168  * Arguments:   @seqwin *s@ = sequence-checking window
1169  *              @uint32 q@ = sequence number to check
1170  *              @const char *service@ = service to report message from
1171  *
1172  * Returns:     A @SEQ_@ code.
1173  *
1174  * Use:         Checks a sequence number against the window, updating things
1175  *              as necessary.
1176  */
1177
1178 extern int seq_check(seqwin */*s*/, uint32 /*q*/, const char */*service*/);
1179
1180 /* --- @versioncmp@ --- *
1181  *
1182  * Arguments:   @const char *va, *vb@ = two version strings
1183  *
1184  * Returns:     Less than, equal to, or greater than zero, according to
1185  *              whether @va@ is less than, equal to, or greater than @vb@.
1186  *
1187  * Use:         Compares version number strings.
1188  *
1189  *              The algorithm is an extension of the Debian version
1190  *              comparison algorithm.  A version number consists of three
1191  *              components:
1192  *
1193  *                [EPOCH :] MAIN [- SUB]
1194  *
1195  *              The MAIN part may contain colons or hyphens if there is an
1196  *              EPOCH or SUB, respectively.  Version strings are compared
1197  *              componentwise: first epochs, then main parts, and finally
1198  *              subparts.
1199  *
1200  *              The component comparison is done as follows.  First, the
1201  *              initial subsequence of nondigit characters is extracted from
1202  *              each string, and these are compared lexicographically, using
1203  *              ASCII ordering, except that letters precede non-letters.  If
1204  *              both are the same, an initial sequence of digits is extracted
1205  *              from the remaining parts of the version strings, and these
1206  *              are compared numerically (an empty sequence being considered
1207  *              to have the value zero).  This process is repeated until we
1208  *              have a winner or until both strings are exhausted.
1209  */
1210
1211 extern int versioncmp(const char */*va*/, const char */*vb*/);
1212
1213 /*----- That's all, folks -------------------------------------------------*/
1214
1215 #ifdef __cplusplus
1216   }
1217 #endif
1218
1219 #endif