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

   1 /* -*-c-*-
   2  *
   3  * Main header file for TrIPE
   4  *
   5  * (c) 2001 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Trivial IP Encryption (TrIPE).
  11  *
  12  * TrIPE is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * TrIPE is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with TrIPE; if not, write to the Free Software Foundation,
  24  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25  */
  26
  27 #ifndef TRIPE_H
  28 #define TRIPE_H
  29
  30 #ifdef __cplusplus
  31   extern "C" {
  32 #endif
  33
  34 /*----- Header files ------------------------------------------------------*/
  35
  36 #include "config.h"
  37
  38 #include <assert.h>
  39 #include <ctype.h>
  40 #include <errno.h>
  41 #include <limits.h>
  42 #include <signal.h>
  43 #include <stdarg.h>
  44 #include <stddef.h>
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <string.h>
  48 #include <time.h>
  49
  50 #include <sys/types.h>
  51 #include <sys/time.h>
  52 #include <unistd.h>
  53 #include <fcntl.h>
  54 #include <sys/stat.h>
  55
  56 #include <sys/socket.h>
  57 #include <sys/un.h>
  58 #include <netinet/in.h>
  59 #include <arpa/inet.h>
  60 #include <netdb.h>
  61
  62 #include <pwd.h>
  63 #include <grp.h>
  64
  65 #include <mLib/alloc.h>
  66 #include <mLib/arena.h>
  67 #include <mLib/base64.h>
  68 #include <mLib/bres.h>
  69 #include <mLib/daemonize.h>
  70 #include <mLib/dstr.h>
  71 #include <mLib/env.h>
  72 #include <mLib/fdflags.h>
  73 #include <mLib/fwatch.h>
  74 #include <mLib/hash.h>
  75 #include <mLib/macros.h>
  76 #include <mLib/mdwopt.h>
  77 #include <mLib/quis.h>
  78 #include <mLib/report.h>
  79 #include <mLib/sel.h>
  80 #include <mLib/selbuf.h>
  81 #include <mLib/sig.h>
  82 #include <mLib/str.h>
  83 #include <mLib/sub.h>
  84 #include <mLib/trace.h>
  85 #include <mLib/tv.h>
  86 #include <mLib/versioncmp.h>
  87
  88 #include <catacomb/buf.h>
  89
  90 #include <catacomb/gcipher.h>
  91 #include <catacomb/gmac.h>
  92 #include <catacomb/grand.h>
  93 #include <catacomb/key.h>
  94 #include <catacomb/paranoia.h>
  95
  96 #include <catacomb/noise.h>
  97 #include <catacomb/rand.h>
  98
  99 #include <catacomb/mp.h>
 100 #include <catacomb/mprand.h>
 101 #include <catacomb/dh.h>
 102 #include <catacomb/ec.h>
 103 #include <catacomb/ec-keys.h>
 104 #include <catacomb/group.h>
 105
 106 #include "protocol.h"
 107 #include "util.h"
 108
 109 #undef sun
 110
 111 /*----- Magic numbers -----------------------------------------------------*/
 112
 113 /* --- Trace flags --- */
 114
 115 #define T_TUNNEL 1u
 116 #define T_PEER 2u
 117 #define T_PACKET 4u
 118 #define T_ADMIN 8u
 119 #define T_CRYPTO 16u
 120 #define T_KEYSET 32u
 121 #define T_KEYEXCH 64u
 122 #define T_KEYMGMT 128u
 123 #define T_CHAL 256u
 124
 125 #define T_ALL 511u
 126
 127 /* --- Units --- */
 128
 129 #define SEC(n) (n##u)
 130 #define MIN(n) (n##u * 60u)
 131 #define MEG(n) (n##ul * 1024ul * 1024ul)
 132
 133 /* --- Other things --- */
 134
 135 #define PKBUFSZ 65536
 136
 137 /*----- Cipher selections -------------------------------------------------*/
 138
 139 typedef struct algswitch {
 140   const gccipher *c;                    /* Symmetric encryption scheme */
 141   const gccipher *mgf;                  /* Mask-generation function */
 142   const gchash *h;                      /* Hash function */
 143   const gcmac *m;                       /* Message authentication code */
 144   size_t hashsz;                        /* Hash output size */
 145   size_t tagsz;                         /* Length to truncate MAC tags */
 146   size_t cksz, mksz;                    /* Key lengths for @c@ and @m@ */
 147 } algswitch;
 148
 149 extern algswitch algs;
 150
 151 #define MAXHASHSZ 64                    /* Largest possible hash size */
 152
 153 #define HASH_STRING(h, s) GH_HASH((h), (s), sizeof(s))
 154
 155 /*----- Data structures ---------------------------------------------------*/
 156
 157 /* --- Socket addresses --- *
 158  *
 159  * A magic union of supported socket addresses.
 160  */
 161
 162 typedef union addr {
 163   struct sockaddr sa;
 164   struct sockaddr_in sin;
 165 } addr;
 166
 167 /* --- Mapping keyed on addresses --- */
 168
 169 typedef struct addrmap {
 170   hash_table t;
 171   size_t load;
 172 } addrmap;
 173
 174 typedef struct addrmap_base {
 175   hash_base b;
 176   addr a;
 177 } addrmap_base;
 178
 179 /* --- Sequence number checking --- */
 180
 181 typedef struct seqwin {
 182   uint32 seq;                           /* First acceptable input sequence */
 183   uint32 win;                           /* Window of acceptable numbers */
 184 } seqwin;
 185
 186 #define SEQ_WINSZ 32                    /* Bits in sequence number window */
 187
 188 /* --- A symmetric keyset --- *
 189  *
 190  * A keyset contains a set of symmetric keys for encrypting and decrypting
 191  * packets.  Keysets are stored in a list, sorted in reverse order of
 192  * creation, so that the most recent keyset (the one most likely to be used)
 193  * is first.
 194  *
 195  * Each keyset has a time limit and a data limit.  The keyset is destroyed
 196  * when either it has existed for too long, or it has been used to encrypt
 197  * too much data.  New key exchanges are triggered when keys are close to
 198  * expiry.
 199  */
 200
 201 typedef struct keyset {
 202   struct keyset *next;                  /* Next active keyset in the list */
 203   unsigned ref;                         /* Reference count for keyset */
 204   struct peer *p;                       /* Pointer to peer structure */
 205   time_t t_exp;                         /* Expiry time for this keyset */
 206   unsigned long sz_exp;                 /* Data limit for the keyset */
 207   T( unsigned seq; )                    /* Sequence number for tracing */
 208   unsigned f;                           /* Various useful flags */
 209   gcipher *cin, *cout;                  /* Keyset ciphers for encryption */
 210   size_t tagsz;                         /* Length to truncate MAC tags */
 211   gmac *min, *mout;                     /* Keyset MACs for integrity */
 212   uint32 oseq;                          /* Outbound sequence number */
 213   seqwin iseq;                          /* Inbound sequence number */
 214 } keyset;
 215
 216 #define KSF_LISTEN 1u                   /* Don't encrypt packets yet */
 217 #define KSF_LINK 2u                     /* Key is in a linked list */
 218
 219 /* --- Key exchange --- *
 220  *
 221  * TrIPE uses the Wrestlers Protocol for its key exchange.  The Wrestlers
 222  * Protocol has a number of desirable features (e.g., perfect forward
 223  * secrecy, and zero-knowledge authentication) which make it attractive for
 224  * use in TrIPE.  The Wrestlers Protocol was designed by Mark Wooding and
 225  * Clive Jones.
 226  */
 227
 228 #define KX_NCHAL 16u
 229
 230 typedef struct kxchal {
 231   struct keyexch *kx;                   /* Pointer back to key exchange */
 232   ge *c;                                /* Responder's challenge */
 233   ge *r;                                /* My reply to the challenge */
 234   keyset *ks;                           /* Pointer to temporary keyset */
 235   unsigned f;                           /* Various useful flags */
 236   sel_timer t;                          /* Response timer for challenge */
 237   octet hc[MAXHASHSZ];                  /* Hash of his challenge */
 238   octet ck[MAXHASHSZ];                  /* His magical check value */
 239   octet hswrq_in[MAXHASHSZ];            /* Inbound switch request message */
 240   octet hswok_in[MAXHASHSZ];            /* Inbound switch confirmation */
 241   octet hswrq_out[MAXHASHSZ];           /* Outbound switch request message */
 242   octet hswok_out[MAXHASHSZ];           /* Outbound switch confirmation */
 243 } kxchal;
 244
 245 typedef struct keyexch {
 246   struct peer *p;                       /* Pointer back to the peer */
 247   keyset **ks;                          /* Peer's list of keysets */
 248   unsigned f;                           /* Various useful flags */
 249   unsigned s;                           /* Current state in exchange */
 250   sel_timer t;                          /* Timer for next exchange */
 251   ge *kpub;                             /* Peer's public key */
 252   time_t texp_kpub;                     /* Expiry time for public key */
 253   mp *alpha;                            /* My temporary secret */
 254   ge *c;                                /* My challenge */
 255   ge *rx;                               /* The expected response */
 256   unsigned nr;                          /* Number of extant responses */
 257   time_t t_valid;                       /* When this exchange goes bad */
 258   octet hc[MAXHASHSZ];                  /* Hash of my challenge */
 259   kxchal *r[KX_NCHAL];                  /* Array of challenges */
 260 } keyexch;
 261
 262 #define KXF_TIMER 1u                    /* Waiting for a timer to go off */
 263 #define KXF_DEAD 2u                     /* The key-exchanger isn't up */
 264 #define KXF_PUBKEY 4u                   /* Key exchanger has a public key */
 265 #define KXF_CORK 8u                     /* Don't send anything yet */
 266
 267 enum {
 268   KXS_DEAD,                             /* Uninitialized state (magical) */
 269   KXS_CHAL,                             /* Main answer-challenges state */
 270   KXS_COMMIT,                           /* Committed: send switch request */
 271   KXS_SWITCH                            /* Switched: send confirmation */
 272 };
 273
 274 /* --- Tunnel structure --- *
 275  *
 276  * Used to maintain system-specific information about the tunnel interface.
 277  */
 278
 279 typedef struct tunnel tunnel;
 280 struct peer;
 281
 282 typedef struct tunnel_ops {
 283   const char *name;                     /* Name of this tunnel driver */
 284   void (*init)(void);                   /* Initializes the system */
 285   tunnel *(*create)(struct peer */*p*/, char **/*ifn*/);
 286                                         /* Initializes a new tunnel */
 287   void (*setifname)(tunnel */*t*/, const char */*ifn*/);
 288                                         /*  Notifies ifname change */
 289   void (*inject)(tunnel */*t*/, buf */*b*/); /* Sends packet through if */
 290   void (*destroy)(tunnel */*t*/);       /* Destroys a tunnel */
 291 } tunnel_ops;
 292
 293 #ifndef TUN_INTERNALS
 294 struct tunnel { const tunnel_ops *ops; };
 295 #endif
 296
 297 /* --- Peer statistics --- *
 298  *
 299  * Contains various interesting and not-so-interesting statistics about a
 300  * peer.  This is updated by various parts of the code.  The format of the
 301  * structure isn't considered private, and @p_stats@ returns a pointer to the
 302  * statistics block for a given peer.
 303  */
 304
 305 typedef struct stats {
 306   unsigned long sz_in, sz_out;          /* Size of all data in and out */
 307   unsigned long sz_kxin, sz_kxout;      /* Size of key exchange messages */
 308   unsigned long sz_ipin, sz_ipout;      /* Size of encapsulated IP packets */
 309   time_t t_start, t_last, t_kx;         /* Time peer created, last pk, kx */
 310   unsigned long n_reject;               /* Number of rejected packets */
 311   unsigned long n_in, n_out;            /* Number of packets in and out */
 312   unsigned long n_kxin, n_kxout;        /* Number of key exchange packets */
 313   unsigned long n_ipin, n_ipout;        /* Number of encrypted packets */
 314 } stats;
 315
 316 /* --- Peer structure --- *
 317  *
 318  * The main structure which glues everything else together.
 319  */
 320
 321 typedef struct peerspec {
 322   char *name;                           /* Peer's name */
 323   const tunnel_ops *tops;               /* Tunnel operations */
 324   unsigned long t_ka;                   /* Keep alive interval */
 325   addr sa;                              /* Socket address to speak to */
 326   size_t sasz;                          /* Socket address size */
 327   unsigned kxf;                         /* Key exchange flags to set */
 328 } peerspec;
 329
 330 typedef struct peer_byname {
 331   sym_base _b;
 332   struct peer *p;
 333 } peer_byname;
 334
 335 typedef struct peer_byaddr {
 336   addrmap_base _b;
 337   struct peer *p;
 338 } peer_byaddr;
 339
 340 typedef struct peer {
 341   peer_byname *byname;                  /* Lookup-by-name block */
 342   peer_byaddr *byaddr;                  /* Lookup-by-address block */
 343   struct ping *pings;                   /* Pings we're waiting for */
 344   peerspec spec;                        /* Specifications for this peer */
 345   tunnel *t;                            /* Tunnel for local packets */
 346   char *ifname;                         /* Interface name for tunnel */
 347   keyset *ks;                           /* List head for keysets */
 348   buf b;                                /* Buffer for sending packets */
 349   stats st;                             /* Statistics */
 350   keyexch kx;                           /* Key exchange protocol block */
 351   sel_timer tka;                        /* Timer for keepalives */
 352 } peer;
 353
 354 typedef struct peer_iter { sym_iter i; } peer_iter;
 355
 356 typedef struct ping {
 357   struct ping *next, *prev;             /* Links to next and previous */
 358   peer *p;                              /* Peer so we can free it */
 359   unsigned msg;                         /* Kind of response expected */
 360   uint32 id;                            /* Id so we can recognize response */
 361   octet magic[32];                      /* Some random data */
 362   sel_timer t;                          /* Timeout for ping */
 363   void (*func)(int /*rc*/, void */*arg*/); /* Function to call when done */
 364   void *arg;                            /* Argument for callback */
 365 } ping;
 366
 367 enum {
 368   PING_NONOTIFY = -1,
 369   PING_OK = 0,
 370   PING_TIMEOUT,
 371   PING_PEERDIED,
 372   PING_MAX
 373 };
 374
 375 /* --- Admin structure --- */
 376
 377 #define OBUFSZ 16384u
 378
 379 typedef struct obuf {
 380   struct obuf *next;                    /* Next buffer in list */
 381   char *p_in, *p_out;                   /* Pointers into the buffer */
 382   char buf[OBUFSZ];                     /* The actual buffer */
 383 } obuf;
 384
 385 typedef struct oqueue {
 386   obuf *hd, *tl;                        /* Head and tail pointers */
 387 } oqueue;
 388
 389 struct admin;
 390
 391 typedef struct admin_bgop {
 392   struct admin_bgop *next, *prev;       /* Links to next and previous */
 393   struct admin *a;                      /* Owner job */
 394   char *tag;                            /* Tag string for messages */
 395   void (*cancel)(struct admin_bgop *);  /* Destructor function */
 396 } admin_bgop;
 397
 398 typedef struct admin_resop {
 399   admin_bgop bg;                        /* Background operation header */
 400   char *addr;                           /* Hostname to be resolved */
 401   bres_client r;                        /* Background resolver task */
 402   sel_timer t;                          /* Timer for resolver */
 403   addr sa;                              /* Socket address */
 404   size_t sasz;                          /* Socket address size */
 405   void (*func)(struct admin_resop *, int); /* Handler */
 406 } admin_resop;
 407
 408 enum { ARES_OK, ARES_FAIL };
 409
 410 typedef struct admin_addop {
 411   admin_resop r;                        /* Name resolution header */
 412   peerspec peer;                        /* Peer pending creation */
 413 } admin_addop;
 414
 415 typedef struct admin_greetop {
 416   admin_resop r;                        /* Name resolution header */
 417   void *c;                              /* Challenge block */
 418   size_t sz;                            /* Length of challenge */
 419 } admin_greetop;
 420
 421 typedef struct admin_pingop {
 422   admin_bgop bg;                        /* Background operation header */
 423   ping ping;                            /* Ping pending response */
 424   struct timeval pingtime;              /* Time last ping was sent */
 425 } admin_pingop;
 426
 427 typedef struct admin_service {
 428   sym_base _b;                          /* Hash table base structure */
 429   char *version;                        /* The provided version */
 430   struct admin *prov;                   /* Which client provides me */
 431   struct admin_service *next, *prev;    /* Client's list of services */
 432 } admin_service;
 433
 434 typedef struct admin_svcop {
 435   admin_bgop bg;                        /* Background operation header */
 436   struct admin *prov;                   /* Client servicing this job */
 437   unsigned short index;                 /* This job's index */
 438   struct admin_svcop *next, *prev;      /* Links for provider's jobs */
 439 } admin_svcop;
 440
 441 typedef struct admin_jobentry {
 442   unsigned short seq;                   /* Zero if unused */
 443   union {
 444     admin_svcop *op;                    /* Operation, if slot in use, ... */
 445     uint32 next;                        /* ... or index of next free slot */
 446   } u;
 447 } admin_jobentry;
 448
 449 typedef struct admin_jobtable {
 450   uint32 n, sz;                         /* Used slots and table size */
 451   admin_svcop *active;                  /* List of active jobs */
 452   uint32 free;                          /* Index of first free slot */
 453   admin_jobentry *v;                    /* And the big array of entries */
 454 } admin_jobtable;
 455
 456 typedef struct admin {
 457   struct admin *next, *prev;            /* Links to next and previous */
 458   unsigned f;                           /* Various useful flags */
 459   unsigned ref;                         /* Reference counter */
 460 #ifndef NTRACE
 461   unsigned seq;                         /* Sequence number for tracing */
 462 #endif
 463   oqueue out;                           /* Output buffer list */
 464   oqueue delay;                         /* Delayed output buffer list */
 465   admin_bgop *bg;                       /* Backgrounded operations */
 466   admin_service *svcs;                  /* Which services I provide */
 467   admin_jobtable j;                     /* Table of outstanding jobs */
 468   selbuf b;                             /* Line buffer for commands */
 469   sel_file w;                           /* Selector for write buffering */
 470 } admin;
 471
 472 #define AF_DEAD 1u                      /* Destroy this admin block */
 473 #define AF_CLOSE 2u                     /* Client closed connection */
 474 #define AF_NOTE 4u                      /* Catch notifications */
 475 #define AF_WARN 8u                      /* Catch warning messages */
 476 #ifndef NTRACE
 477   #define AF_TRACE 16u                  /* Catch tracing */
 478 #endif
 479
 480 #ifndef NTRACE
 481 #  define AF_ALLMSGS (AF_NOTE | AF_TRACE | AF_WARN)
 482 #else
 483 #  define AF_ALLMSGS (AF_NOTE | AF_WARN)
 484 #endif
 485
 486 /*----- Global variables --------------------------------------------------*/
 487
 488 extern sel_state sel;                   /* Global I/O event state */
 489 extern group *gg;                       /* The group we work in */
 490 extern size_t indexsz;                  /* Size of exponent for the group */
 491 extern mp *kpriv;                       /* Our private key */
 492 extern ge *kpub;                        /* Our public key */
 493 extern octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ];
 494 extern const tunnel_ops *tunnels[];     /* Table of tunnels (0-term) */
 495 extern const tunnel_ops *tun_default;   /* Default tunnel to use */
 496
 497 #ifndef NTRACE
 498 extern const trace_opt tr_opts[];       /* Trace options array */
 499 extern unsigned tr_flags;               /* Trace options flags */
 500 #endif
 501
 502 /*----- Other macros ------------------------------------------------------*/
 503
 504 #define TIMER noise_timer(RAND_GLOBAL)
 505
 506 /*----- Key management ----------------------------------------------------*/
 507
 508 /* --- @km_reload@ --- *
 509  *
 510  * Arguments:   ---
 511  *
 512  * Returns:     Zero if OK, nonzero to force reloading of keys.
 513  *
 514  * Use:         Checks the keyrings to see if they need reloading.
 515  */
 516
 517 extern int km_reload(void);
 518
 519 /* --- @km_init@ --- *
 520  *
 521  * Arguments:   @const char *kr_priv@ = private keyring file
 522  *              @const char *kr_pub@ = public keyring file
 523  *              @const char *tag@ = tag to load
 524  *
 525  * Returns:     ---
 526  *
 527  * Use:         Initializes, and loads the private key.
 528  */
 529
 530 extern void km_init(const char */*kr_priv*/, const char */*kr_pub*/,
 531                     const char */*tag*/);
 532
 533 /* --- @km_getpubkey@ --- *
 534  *
 535  * Arguments:   @const char *tag@ = public key tag to load
 536  *              @ge *kpub@ = where to put the public key
 537  *              @time_t *t_exp@ = where to put the expiry time
 538  *
 539  * Returns:     Zero if OK, nonzero if it failed.
 540  *
 541  * Use:         Fetches a public key from the keyring.
 542  */
 543
 544 extern int km_getpubkey(const char */*tag*/, ge */*kpub*/,
 545                         time_t */*t_exp*/);
 546
 547 /*----- Key exchange ------------------------------------------------------*/
 548
 549 /* --- @kx_start@ --- *
 550  *
 551  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 552  *              @int forcep@ = nonzero to ignore the quiet timer
 553  *
 554  * Returns:     ---
 555  *
 556  * Use:         Stimulates a key exchange.  If a key exchage is in progress,
 557  *              a new challenge is sent (unless the quiet timer forbids
 558  *              this); if no exchange is in progress, one is commenced.
 559  */
 560
 561 extern void kx_start(keyexch */*kx*/, int /*forcep*/);
 562
 563 /* --- @kx_message@ --- *
 564  *
 565  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 566  *              @unsigned msg@ = the message code
 567  *              @buf *b@ = pointer to buffer containing the packet
 568  *
 569  * Returns:     ---
 570  *
 571  * Use:         Reads a packet containing key exchange messages and handles
 572  *              it.
 573  */
 574
 575 extern void kx_message(keyexch */*kx*/, unsigned /*msg*/, buf */*b*/);
 576
 577 /* --- @kx_free@ --- *
 578  *
 579  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 580  *
 581  * Returns:     ---
 582  *
 583  * Use:         Frees everything in a key exchange context.
 584  */
 585
 586 extern void kx_free(keyexch */*kx*/);
 587
 588 /* --- @kx_newkeys@ --- *
 589  *
 590  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 591  *
 592  * Returns:     ---
 593  *
 594  * Use:         Informs the key exchange module that its keys may have
 595  *              changed.  If fetching the new keys fails, the peer will be
 596  *              destroyed, we log messages and struggle along with the old
 597  *              keys.
 598  */
 599
 600 extern void kx_newkeys(keyexch */*kx*/);
 601
 602 /* --- @kx_init@ --- *
 603  *
 604  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 605  *              @peer *p@ = pointer to peer context
 606  *              @keyset **ks@ = pointer to keyset list
 607  *              @unsigned f@ = various useful flags
 608  *
 609  * Returns:     Zero if OK, nonzero if it failed.
 610  *
 611  * Use:         Initializes a key exchange module.  The module currently
 612  *              contains no keys, and will attempt to initiate a key
 613  *              exchange.
 614  */
 615
 616 extern int kx_init(keyexch */*kx*/, peer */*p*/,
 617                    keyset **/*ks*/, unsigned /*f*/);
 618
 619 /*----- Keysets and symmetric cryptography --------------------------------*/
 620
 621 /* --- @ks_drop@ --- *
 622  *
 623  * Arguments:   @keyset *ks@ = pointer to a keyset
 624  *
 625  * Returns:     ---
 626  *
 627  * Use:         Decrements a keyset's reference counter.  If the counter hits
 628  *              zero, the keyset is freed.
 629  */
 630
 631 extern void ks_drop(keyset */*ks*/);
 632
 633 /* --- @ks_gen@ --- *
 634  *
 635  * Arguments:   @const void *k@ = pointer to key material
 636  *              @size_t x, y, z@ = offsets into key material (see below)
 637  *              @peer *p@ = pointer to peer information
 638  *
 639  * Returns:     A pointer to the new keyset.
 640  *
 641  * Use:         Derives a new keyset from the given key material.  The
 642  *              offsets @x@, @y@ and @z@ separate the key material into three
 643  *              parts.  Between the @k@ and @k + x@ is `my' contribution to
 644  *              the key material; between @k + x@ and @k + y@ is `your'
 645  *              contribution; and between @k + y@ and @k + z@ is a shared
 646  *              value we made together.  These are used to construct two
 647  *              pairs of symmetric keys.  Each pair consists of an encryption
 648  *              key and a message authentication key.  One pair is used for
 649  *              outgoing messages, the other for incoming messages.
 650  *
 651  *              The new key is marked so that it won't be selected for output
 652  *              by @ksl_encrypt@.  You can still encrypt data with it by
 653  *              calling @ks_encrypt@ directly.
 654  */
 655
 656 extern keyset *ks_gen(const void */*k*/,
 657                       size_t /*x*/, size_t /*y*/, size_t /*z*/,
 658                       peer */*p*/);
 659
 660 /* --- @ks_tregen@ --- *
 661  *
 662  * Arguments:   @keyset *ks@ = pointer to a keyset
 663  *
 664  * Returns:     The time at which moves ought to be made to replace this key.
 665  */
 666
 667 extern time_t ks_tregen(keyset */*ks*/);
 668
 669 /* --- @ks_activate@ --- *
 670  *
 671  * Arguments:   @keyset *ks@ = pointer to a keyset
 672  *
 673  * Returns:     ---
 674  *
 675  * Use:         Activates a keyset, so that it can be used for encrypting
 676  *              outgoing messages.
 677  */
 678
 679 extern void ks_activate(keyset */*ks*/);
 680
 681 /* --- @ks_encrypt@ --- *
 682  *
 683  * Arguments:   @keyset *ks@ = pointer to a keyset
 684  *              @unsigned ty@ = message type
 685  *              @buf *b@ = pointer to input buffer
 686  *              @buf *bb@ = pointer to output buffer
 687  *
 688  * Returns:     Zero if OK, nonzero if the key needs replacing.  If the
 689  *              encryption failed, the output buffer is broken and zero is
 690  *              returned.
 691  *
 692  * Use:         Encrypts a block of data using the key.  Note that the `key
 693  *              ought to be replaced' notification is only ever given once
 694  *              for each key.  Also note that this call forces a keyset to be
 695  *              used even if it's marked as not for data output.
 696  */
 697
 698 extern int ks_encrypt(keyset */*ks*/, unsigned /*ty*/,
 699                       buf */*b*/, buf */*bb*/);
 700
 701 /* --- @ks_decrypt@ --- *
 702  *
 703  * Arguments:   @keyset *ks@ = pointer to a keyset
 704  *              @unsigned ty@ = expected type code
 705  *              @buf *b@ = pointer to an input buffer
 706  *              @buf *bb@ = pointer to an output buffer
 707  *
 708  * Returns:     Zero on success, or nonzero if there was some problem.
 709  *
 710  * Use:         Attempts to decrypt a message using a given key.  Note that
 711  *              requesting decryption with a key directly won't clear a
 712  *              marking that it's not for encryption.
 713  */
 714
 715 extern int ks_decrypt(keyset */*ks*/, unsigned /*ty*/,
 716                       buf */*b*/, buf */*bb*/);
 717
 718 /* --- @ksl_free@ --- *
 719  *
 720  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 721  *
 722  * Returns:     ---
 723  *
 724  * Use:         Frees (releases references to) all of the keys in a keyset.
 725  */
 726
 727 extern void ksl_free(keyset **/*ksroot*/);
 728
 729 /* --- @ksl_link@ --- *
 730  *
 731  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 732  *              @keyset *ks@ = pointer to a keyset
 733  *
 734  * Returns:     ---
 735  *
 736  * Use:         Links a keyset into a list.  A keyset can only be on one list
 737  *              at a time.  Bad things happen otherwise.
 738  */
 739
 740 extern void ksl_link(keyset **/*ksroot*/, keyset */*ks*/);
 741
 742 /* --- @ksl_prune@ --- *
 743  *
 744  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 745  *
 746  * Returns:     ---
 747  *
 748  * Use:         Prunes the keyset list by removing keys which mustn't be used
 749  *              any more.
 750  */
 751
 752 extern void ksl_prune(keyset **/*ksroot*/);
 753
 754 /* --- @ksl_encrypt@ --- *
 755  *
 756  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 757  *              @unsigned ty@ = message type
 758  *              @buf *b@ = pointer to input buffer
 759  *              @buf *bb@ = pointer to output buffer
 760  *
 761  * Returns:     Nonzero if a new key is needed.
 762  *
 763  * Use:         Encrypts a packet.
 764  */
 765
 766 extern int ksl_encrypt(keyset **/*ksroot*/, unsigned /*ty*/,
 767                        buf */*b*/, buf */*bb*/);
 768
 769 /* --- @ksl_decrypt@ --- *
 770  *
 771  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 772  *              @unsigned ty@ = expected type code
 773  *              @buf *b@ = pointer to input buffer
 774  *              @buf *bb@ = pointer to output buffer
 775  *
 776  * Returns:     Nonzero if the packet couldn't be decrypted.
 777  *
 778  * Use:         Decrypts a packet.
 779  */
 780
 781 extern int ksl_decrypt(keyset **/*ksroot*/, unsigned /*ty*/,
 782                        buf */*b*/, buf */*bb*/);
 783
 784 /*----- Challenges --------------------------------------------------------*/
 785
 786 /* --- @c_new@ --- *
 787  *
 788  * Arguments:   @buf *b@ = where to put the challenge
 789  *
 790  * Returns:     Zero if OK, nonzero on error.
 791  *
 792  * Use:         Issues a new challenge.
 793  */
 794
 795 extern int c_new(buf */*b*/);
 796
 797 /* --- @c_check@ --- *
 798  *
 799  * Arguments:   @buf *b@ = where to find the challenge
 800  *
 801  * Returns:     Zero if OK, nonzero if it didn't work.
 802  *
 803  * Use:         Checks a challenge.  On failure, the buffer is broken.
 804  */
 805
 806 extern int c_check(buf */*b*/);
 807
 808 /*----- Administration interface ------------------------------------------*/
 809
 810 #define A_END ((char *)0)
 811
 812 /* --- @a_warn@ --- *
 813  *
 814  * Arguments:   @const char *fmt@ = pointer to format string
 815  *              @...@ = other arguments
 816  *
 817  * Returns:     ---
 818  *
 819  * Use:         Informs all admin connections of a warning.
 820  */
 821
 822 extern void a_warn(const char */*fmt*/, ...);
 823
 824 /* --- @a_notify@ --- *
 825  *
 826  * Arguments:   @const char *fmt@ = pointer to format string
 827  *              @...@ = other arguments
 828  *
 829  * Returns:     ---
 830  *
 831  * Use:         Sends a notification to interested admin connections.
 832  */
 833
 834 extern void a_notify(const char */*fmt*/, ...);
 835
 836 /* --- @a_create@ --- *
 837  *
 838  * Arguments:   @int fd_in, fd_out@ = file descriptors to use
 839  *              @unsigned f@ = initial flags to set
 840  *
 841  * Returns:     ---
 842  *
 843  * Use:         Creates a new admin connection.
 844  */
 845
 846 extern void a_create(int /*fd_in*/, int /*fd_out*/, unsigned /*f*/);
 847
 848 /* --- @a_quit@ --- *
 849  *
 850  * Arguments:   ---
 851  *
 852  * Returns:     ---
 853  *
 854  * Use:         Shuts things down nicely.
 855  */
 856
 857 extern void a_quit(void);
 858
 859 /* --- @a_preselect@ --- *
 860  *
 861  * Arguments:   ---
 862  *
 863  * Returns:     ---
 864  *
 865  * Use:         Informs the admin module that we're about to select again,
 866  *              and that it should do cleanup things it has delayed until a
 867  *              `safe' time.
 868  */
 869
 870 extern void a_preselect(void);
 871
 872 /* --- @a_daemon@ --- *
 873  *
 874  * Arguments:   ---
 875  *
 876  * Returns:     ---
 877  *
 878  * Use:         Informs the admin module that it's a daemon.
 879  */
 880
 881 extern void a_daemon(void);
 882
 883 /* --- @a_init@ --- *
 884  *
 885  * Arguments:   @const char *sock@ = socket name to create
 886  *
 887  * Returns:     ---
 888  *
 889  * Use:         Creates the admin listening socket.
 890  */
 891
 892 extern void a_init(const char */*sock*/);
 893
 894 /*----- Mapping with addresses as keys ------------------------------------*/
 895
 896 /* --- @am_create@ --- *
 897  *
 898  * Arguments:   @addrmap *m@ = pointer to map
 899  *
 900  * Returns:     ---
 901  *
 902  * Use:         Create an address map, properly set up.
 903  */
 904
 905 extern void am_create(addrmap */*m*/);
 906
 907 /* --- @am_destroy@ --- *
 908  *
 909  * Arguments:   @addrmap *m@ = pointer to map
 910  *
 911  * Returns:     ---
 912  *
 913  * Use:         Destroy an address map, throwing away all the entries.
 914  */
 915
 916 extern void am_destroy(addrmap */*m*/);
 917
 918 /* --- @am_find@ --- *
 919  *
 920  * Arguments:   @addrmap *m@ = pointer to map
 921  *              @const addr *a@ = address to look up
 922  *              @size_t sz@ = size of block to allocate
 923  *              @unsigned *f@ = where to store flags
 924  *
 925  * Returns:     Pointer to found item, or null.
 926  *
 927  * Use:         Finds a record with the given IP address, set @*f@ nonzero
 928  *              and returns it.  If @sz@ is zero, and no match was found,
 929  *              return null; otherwise allocate a new block of @sz@ bytes,
 930  *              clear @*f@ to zero and return the block pointer.
 931  */
 932
 933 extern void *am_find(addrmap */*m*/, const addr */*a*/,
 934                      size_t /*sz*/, unsigned */*f*/);
 935
 936 /* --- @am_remove@ --- *
 937  *
 938  * Arguments:   @addrmap *m@ = pointer to map
 939  *              @void *i@ = pointer to the item
 940  *
 941  * Returns:     ---
 942  *
 943  * Use:         Removes an item from the map.
 944  */
 945
 946 extern void am_remove(addrmap */*m*/, void */*i*/);
 947
 948 /*----- Peer management ---------------------------------------------------*/
 949
 950 /* --- @p_txstart@ --- *
 951  *
 952  * Arguments:   @peer *p@ = pointer to peer block
 953  *              @unsigned msg@ = message type code
 954  *
 955  * Returns:     A pointer to a buffer to write to.
 956  *
 957  * Use:         Starts sending to a peer.  Only one send can happen at a
 958  *              time.
 959  */
 960
 961 extern buf *p_txstart(peer */*p*/, unsigned /*msg*/);
 962
 963 /* --- @p_txend@ --- *
 964  *
 965  * Arguments:   @peer *p@ = pointer to peer block
 966  *
 967  * Returns:     ---
 968  *
 969  * Use:         Sends a packet to the peer.
 970  */
 971
 972 extern void p_txend(peer */*p*/);
 973
 974 /* --- @p_pingsend@ --- *
 975  *
 976  * Arguments:   @peer *p@ = destination peer
 977  *              @ping *pg@ = structure to fill in
 978  *              @unsigned type@ = message type
 979  *              @unsigned long timeout@ = how long to wait before giving up
 980  *              @void (*func)(int, void *)@ = callback function
 981  *              @void *arg@ = argument for callback
 982  *
 983  * Returns:     Zero if successful, nonzero if it failed.
 984  *
 985  * Use:         Sends a ping to a peer.  Call @func@ with a nonzero argument
 986  *              if we get an answer within the timeout, or zero if no answer.
 987  */
 988
 989 extern int p_pingsend(peer */*p*/, ping */*pg*/, unsigned /*type*/,
 990                       unsigned long /*timeout*/,
 991                       void (*/*func*/)(int, void *), void */*arg*/);
 992
 993 /* --- @p_pingdone@ --- *
 994  *
 995  * Arguments:   @ping *p@ = ping structure
 996  *              @int rc@ = return code to pass on
 997  *
 998  * Returns:     ---
 999  *
1000  * Use:         Disposes of a ping structure, maybe sending a notification.
1001  */
1002
1003 extern void p_pingdone(ping */*p*/, int /*rc*/);
1004
1005 /* --- @p_greet@ --- *
1006  *
1007  * Arguments:   @peer *p@ = peer to send to
1008  *              @const void *c@ = pointer to challenge
1009  *              @size_t sz@ = size of challenge
1010  *
1011  * Returns:     ---
1012  *
1013  * Use:         Sends a greeting packet.
1014  */
1015
1016 extern void p_greet(peer */*p*/, const void */*c*/, size_t /*sz*/);
1017
1018 /* --- @p_tun@ --- *
1019  *
1020  * Arguments:   @peer *p@ = pointer to peer block
1021  *              @buf *b@ = buffer containing incoming packet
1022  *
1023  * Returns:     ---
1024  *
1025  * Use:         Handles a packet which needs to be sent to a peer.
1026  */
1027
1028 extern void p_tun(peer */*p*/, buf */*b*/);
1029
1030 /* --- @p_keyreload@ --- *
1031  *
1032  * Arguments:   ---
1033  *
1034  * Returns:     ---
1035  *
1036  * Use:         Forces a check of the daemon's keyring files.
1037  */
1038
1039 extern void p_keyreload(void);
1040
1041 /* --- @p_interval@ --- *
1042  *
1043  * Arguments:   ---
1044  *
1045  * Returns:     ---
1046  *
1047  * Use:         Called periodically to do tidying.
1048  */
1049
1050 extern void p_interval(void);
1051
1052 /* --- @p_stats@ --- *
1053  *
1054  * Arguments:   @peer *p@ = pointer to a peer block
1055  *
1056  * Returns:     A pointer to the peer's statistics.
1057  */
1058
1059 extern stats *p_stats(peer */*p*/);
1060
1061 /* --- @p_ifname@ --- *
1062  *
1063  * Arguments:   @peer *p@ = pointer to a peer block
1064  *
1065  * Returns:     A pointer to the peer's interface name.
1066  */
1067
1068 extern const char *p_ifname(peer */*p*/);
1069
1070 /* --- @p_setifname@ --- *
1071  *
1072  * Arguments:   @peer *p@ = pointer to a peer block
1073  *              @const char *name@ = pointer to the new name
1074  *
1075  * Returns:     ---
1076  *
1077  * Use:         Changes the name held for a peer's interface.
1078  */
1079
1080 extern void p_setifname(peer */*p*/, const char */*name*/);
1081
1082 /* --- @p_addr@ --- *
1083  *
1084  * Arguments:   @peer *p@ = pointer to a peer block
1085  *
1086  * Returns:     A pointer to the peer's address.
1087  */
1088
1089 extern const addr *p_addr(peer */*p*/);
1090
1091 /* --- @p_init@ --- *
1092  *
1093  * Arguments:   @struct in_addr addr@ = address to bind to
1094  *              @unsigned port@ = port number to listen to
1095  *
1096  * Returns:     ---
1097  *
1098  * Use:         Initializes the peer system; creates the socket.
1099  */
1100
1101 extern void p_init(struct in_addr /*addr*/, unsigned /*port*/);
1102
1103 /* --- @p_port@ --- *
1104  *
1105  * Arguments:   ---
1106  *
1107  * Returns:     Port number used for socket.
1108  */
1109
1110 unsigned p_port(void);
1111
1112 /* --- @p_create@ --- *
1113  *
1114  * Arguments:   @peerspec *spec@ = information about this peer
1115  *
1116  * Returns:     Pointer to the peer block, or null if it failed.
1117  *
1118  * Use:         Creates a new named peer block.  No peer is actually attached
1119  *              by this point.
1120  */
1121
1122 extern peer *p_create(peerspec */*spec*/);
1123
1124 /* --- @p_name@ --- *
1125  *
1126  * Arguments:   @peer *p@ = pointer to a peer block
1127  *
1128  * Returns:     A pointer to the peer's name.
1129  *
1130  * Use:         Equivalent to @p_spec(p)->name@.
1131  */
1132
1133 extern const char *p_name(peer */*p*/);
1134
1135 /* --- @p_spec@ --- *
1136  *
1137  * Arguments:   @peer *p@ = pointer to a peer block
1138  *
1139  * Returns:     Pointer to the peer's specification
1140  */
1141
1142 extern const peerspec *p_spec(peer */*p*/);
1143
1144 /* --- @p_findbyaddr@ --- *
1145  *
1146  * Arguments:   @const addr *a@ = address to look up
1147  *
1148  * Returns:     Pointer to the peer block, or null if not found.
1149  *
1150  * Use:         Finds a peer by address.
1151  */
1152
1153 extern peer *p_findbyaddr(const addr */*a*/);
1154
1155 /* --- @p_find@ --- *
1156  *
1157  * Arguments:   @const char *name@ = name to look up
1158  *
1159  * Returns:     Pointer to the peer block, or null if not found.
1160  *
1161  * Use:         Finds a peer by name.
1162  */
1163
1164 extern peer *p_find(const char */*name*/);
1165
1166 /* --- @p_destroy@ --- *
1167  *
1168  * Arguments:   @peer *p@ = pointer to a peer
1169  *
1170  * Returns:     ---
1171  *
1172  * Use:         Destroys a peer.
1173  */
1174
1175 extern void p_destroy(peer */*p*/);
1176
1177 /* --- @FOREACH_PEER@ --- *
1178  *
1179  * Arguments:   @p@ = name to bind to each peer
1180  *              @stuff@ = thing to do for each item
1181  *
1182  * Use:         Does something for each current peer.
1183  */
1184
1185 #define FOREACH_PEER(p, stuff) do {                                     \
1186   peer_iter i_;                                                         \
1187   peer *p;                                                              \
1188   for (p_mkiter(&i_); (p = p_next(&i_)) != 0; ) do stuff while (0);     \
1189 } while (0)
1190
1191 /* --- @p_mkiter@ --- *
1192  *
1193  * Arguments:   @peer_iter *i@ = pointer to an iterator
1194  *
1195  * Returns:     ---
1196  *
1197  * Use:         Initializes the iterator.
1198  */
1199
1200 extern void p_mkiter(peer_iter */*i*/);
1201
1202 /* --- @p_next@ --- *
1203  *
1204  * Arguments:   @peer_iter *i@ = pointer to an iterator
1205  *
1206  * Returns:     Next peer, or null if at the end.
1207  *
1208  * Use:         Returns the next peer.
1209  */
1210
1211 extern peer *p_next(peer_iter */*i*/);
1212
1213 /*----- Tunnel drivers ----------------------------------------------------*/
1214
1215 #ifdef TUN_LINUX
1216   extern const tunnel_ops tun_linux;
1217 #endif
1218
1219 #ifdef TUN_UNET
1220   extern const tunnel_ops tun_unet;
1221 #endif
1222
1223 #ifdef TUN_BSD
1224   extern const tunnel_ops tun_bsd;
1225 #endif
1226
1227 extern const tunnel_ops tun_slip;
1228
1229 /*----- Other handy utilities ---------------------------------------------*/
1230
1231 /* --- @mpstr@ --- *
1232  *
1233  * Arguments:   @mp *m@ = a multiprecision integer
1234  *
1235  * Returns:     A pointer to the integer's textual representation.
1236  *
1237  * Use:         Converts a multiprecision integer to a string.  Corrupts
1238  *              @buf_t@.
1239  */
1240
1241 extern const char *mpstr(mp */*m*/);
1242
1243 /* --- @gestr@ --- *
1244  *
1245  * Arguments:   @group *g@ = a group
1246  *              @ge *x@ = a group element
1247  *
1248  * Returns:     A pointer to the element's textual representation.
1249  *
1250  * Use:         Converts a group element to a string.  Corrupts
1251  *              @buf_t@.
1252  */
1253
1254 extern const char *gestr(group */*g*/, ge */*x*/);
1255
1256 /* --- @timestr@ --- *
1257  *
1258  * Arguments:   @time_t t@ = a time to convert
1259  *
1260  * Returns:     A pointer to a textual representation of the time.
1261  *
1262  * Use:         Converts a time to a textual representation.  Corrupts
1263  *              @buf_t@.
1264  */
1265
1266 extern const char *timestr(time_t /*t*/);
1267
1268 /* --- @mystrieq@ --- *
1269  *
1270  * Arguments:   @const char *x, *y@ = two strings
1271  *
1272  * Returns:     True if @x@ and @y are equal, up to case.
1273  */
1274
1275 extern int mystrieq(const char */*x*/, const char */*y*/);
1276
1277 /* --- @seq_reset@ --- *
1278  *
1279  * Arguments:   @seqwin *s@ = sequence-checking window
1280  *
1281  * Returns:     ---
1282  *
1283  * Use:         Resets a sequence number window.
1284  */
1285
1286 extern void seq_reset(seqwin */*s*/);
1287
1288 /* --- @seq_check@ --- *
1289  *
1290  * Arguments:   @seqwin *s@ = sequence-checking window
1291  *              @uint32 q@ = sequence number to check
1292  *              @const char *service@ = service to report message from
1293  *
1294  * Returns:     A @SEQ_@ code.
1295  *
1296  * Use:         Checks a sequence number against the window, updating things
1297  *              as necessary.
1298  */
1299
1300 extern int seq_check(seqwin */*s*/, uint32 /*q*/, const char */*service*/);
1301
1302 /*----- That's all, folks -------------------------------------------------*/
1303
1304 #ifdef __cplusplus
1305   }
1306 #endif
1307
1308 #endif