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 #include <sys/wait.h>
  56
  57 #include <sys/socket.h>
  58 #include <sys/un.h>
  59 #include <netinet/in.h>
  60 #include <arpa/inet.h>
  61 #include <netdb.h>
  62
  63 #include <pwd.h>
  64 #include <grp.h>
  65
  66 #include <mLib/alloc.h>
  67 #include <mLib/arena.h>
  68 #include <mLib/base64.h>
  69 #include <mLib/bres.h>
  70 #include <mLib/daemonize.h>
  71 #include <mLib/dstr.h>
  72 #include <mLib/env.h>
  73 #include <mLib/fdflags.h>
  74 #include <mLib/fdpass.h>
  75 #include <mLib/fwatch.h>
  76 #include <mLib/hash.h>
  77 #include <mLib/macros.h>
  78 #include <mLib/mdup.h>
  79 #include <mLib/mdwopt.h>
  80 #include <mLib/quis.h>
  81 #include <mLib/report.h>
  82 #include <mLib/sel.h>
  83 #include <mLib/selbuf.h>
  84 #include <mLib/sig.h>
  85 #include <mLib/str.h>
  86 #include <mLib/sub.h>
  87 #include <mLib/trace.h>
  88 #include <mLib/tv.h>
  89 #include <mLib/versioncmp.h>
  90
  91 #include <catacomb/buf.h>
  92
  93 #include <catacomb/gcipher.h>
  94 #include <catacomb/gmac.h>
  95 #include <catacomb/grand.h>
  96 #include <catacomb/key.h>
  97 #include <catacomb/paranoia.h>
  98
  99 #include <catacomb/noise.h>
 100 #include <catacomb/rand.h>
 101
 102 #include <catacomb/mp.h>
 103 #include <catacomb/mprand.h>
 104 #include <catacomb/dh.h>
 105 #include <catacomb/ec.h>
 106 #include <catacomb/ec-keys.h>
 107 #include <catacomb/group.h>
 108
 109 #include "priv.h"
 110 #include "protocol.h"
 111 #include "slip.h"
 112 #include "util.h"
 113
 114 #undef sun
 115
 116 /*----- Magic numbers -----------------------------------------------------*/
 117
 118 /* --- Trace flags --- */
 119
 120 #define T_TUNNEL 1u
 121 #define T_PEER 2u
 122 #define T_PACKET 4u
 123 #define T_ADMIN 8u
 124 #define T_CRYPTO 16u
 125 #define T_KEYSET 32u
 126 #define T_KEYEXCH 64u
 127 #define T_KEYMGMT 128u
 128 #define T_CHAL 256u
 129 /* T_PRIVSEP  in priv.h */
 130
 131 #define T_ALL 1023u
 132
 133 /* --- Units --- */
 134
 135 #define SEC(n) (n##u)
 136 #define MIN(n) (n##u * 60u)
 137 #define MEG(n) (n##ul * 1024ul * 1024ul)
 138
 139 /* --- Other things --- */
 140
 141 #define PKBUFSZ 65536
 142
 143 /*----- Cipher selections -------------------------------------------------*/
 144
 145 typedef struct algswitch {
 146   const gccipher *c;                    /* Symmetric encryption scheme */
 147   const gccipher *mgf;                  /* Mask-generation function */
 148   const gchash *h;                      /* Hash function */
 149   const gcmac *m;                       /* Message authentication code */
 150   size_t hashsz;                        /* Hash output size */
 151   size_t tagsz;                         /* Length to truncate MAC tags */
 152   size_t expsz;                         /* Size of data to process */
 153   size_t cksz, mksz;                    /* Key lengths for @c@ and @m@ */
 154 } algswitch;
 155
 156 typedef struct kdata {
 157   unsigned ref;                         /* Reference counter */
 158   struct knode *kn;                     /* Pointer to cache entry */
 159   char *tag;                            /* Full tag name of the key */
 160   group *g;                             /* The group we work in */
 161   size_t indexsz;                       /* Size of exponent for the group */
 162   mp *kpriv;                            /* The private key (or null) */
 163   ge *kpub;                             /* The public key */
 164   time_t t_exp;                         /* Expiry time of the key */
 165   algswitch algs;                       /* Collection of algorithms */
 166 } kdata;
 167
 168 typedef struct knode {
 169   sym_base _b;                          /* Symbol table intrusion */
 170   unsigned f;                           /* Various flags */
 171 #define KNF_BROKEN 1u                   /*   Don't use this key any more */
 172   struct keyhalf *kh;                   /* Pointer to the home keyhalf */
 173   kdata *kd;                            /* Pointer to the key data */
 174 } knode;
 175
 176 #define MAXHASHSZ 64                    /* Largest possible hash size */
 177
 178 #define HASH_STRING(h, s) GH_HASH((h), (s), sizeof(s))
 179
 180 /*----- Data structures ---------------------------------------------------*/
 181
 182 /* --- Socket addresses --- *
 183  *
 184  * A magic union of supported socket addresses.
 185  */
 186
 187 typedef union addr {
 188   struct sockaddr sa;
 189   struct sockaddr_in sin;
 190 } addr;
 191
 192 /* --- Mapping keyed on addresses --- */
 193
 194 typedef struct addrmap {
 195   hash_table t;
 196   size_t load;
 197 } addrmap;
 198
 199 typedef struct addrmap_base {
 200   hash_base b;
 201   addr a;
 202 } addrmap_base;
 203
 204 /* --- Sequence number checking --- */
 205
 206 typedef struct seqwin {
 207   uint32 seq;                           /* First acceptable input sequence */
 208   uint32 win;                           /* Window of acceptable numbers */
 209 } seqwin;
 210
 211 #define SEQ_WINSZ 32                    /* Bits in sequence number window */
 212
 213 /* --- A symmetric keyset --- *
 214  *
 215  * A keyset contains a set of symmetric keys for encrypting and decrypting
 216  * packets.  Keysets are stored in a list, sorted in reverse order of
 217  * creation, so that the most recent keyset (the one most likely to be used)
 218  * is first.
 219  *
 220  * Each keyset has a time limit and a data limit.  The keyset is destroyed
 221  * when either it has existed for too long, or it has been used to encrypt
 222  * too much data.  New key exchanges are triggered when keys are close to
 223  * expiry.
 224  */
 225
 226 typedef struct keyset {
 227   struct keyset *next;                  /* Next active keyset in the list */
 228   unsigned ref;                         /* Reference count for keyset */
 229   struct peer *p;                       /* Pointer to peer structure */
 230   time_t t_exp;                         /* Expiry time for this keyset */
 231   unsigned long sz_exp, sz_regen;       /* Data limits for the keyset */
 232   T( unsigned seq; )                    /* Sequence number for tracing */
 233   unsigned f;                           /* Various useful flags */
 234   gcipher *cin, *cout;                  /* Keyset ciphers for encryption */
 235   size_t tagsz;                         /* Length to truncate MAC tags */
 236   gmac *min, *mout;                     /* Keyset MACs for integrity */
 237   uint32 oseq;                          /* Outbound sequence number */
 238   seqwin iseq;                          /* Inbound sequence number */
 239 } keyset;
 240
 241 #define KSF_LISTEN 1u                   /* Don't encrypt packets yet */
 242 #define KSF_LINK 2u                     /* Key is in a linked list */
 243
 244 #define KSERR_REGEN -1                  /* Regenerate keys */
 245 #define KSERR_NOKEYS -2                 /* No keys left */
 246 #define KSERR_DECRYPT -3                /* Unable to decrypt message */
 247 #define KSERR_SEQ -4                    /* Incorrect sequence number */
 248 #define KSERR_MALFORMED -5              /* Input ciphertext is broken */
 249
 250 /* --- Key exchange --- *
 251  *
 252  * TrIPE uses the Wrestlers Protocol for its key exchange.  The Wrestlers
 253  * Protocol has a number of desirable features (e.g., perfect forward
 254  * secrecy, and zero-knowledge authentication) which make it attractive for
 255  * use in TrIPE.  The Wrestlers Protocol was designed by Mark Wooding and
 256  * Clive Jones.
 257  */
 258
 259 #define KX_NCHAL 16u
 260
 261 typedef struct kxchal {
 262   struct keyexch *kx;                   /* Pointer back to key exchange */
 263   ge *c;                                /* Responder's challenge */
 264   ge *r;                                /* My reply to the challenge */
 265   keyset *ks;                           /* Pointer to temporary keyset */
 266   unsigned f;                           /* Various useful flags */
 267   sel_timer t;                          /* Response timer for challenge */
 268   octet hc[MAXHASHSZ];                  /* Hash of his challenge */
 269   octet ck[MAXHASHSZ];                  /* His magical check value */
 270   octet hswrq_in[MAXHASHSZ];            /* Inbound switch request message */
 271   octet hswok_in[MAXHASHSZ];            /* Inbound switch confirmation */
 272   octet hswrq_out[MAXHASHSZ];           /* Outbound switch request message */
 273   octet hswok_out[MAXHASHSZ];           /* Outbound switch confirmation */
 274 } kxchal;
 275
 276 typedef struct keyexch {
 277   struct peer *p;                       /* Pointer back to the peer */
 278   kdata *kpriv;                         /* Private key and related info */
 279   kdata *kpub;                          /* Peer's public key */
 280   keyset **ks;                          /* Peer's list of keysets */
 281   unsigned f;                           /* Various useful flags */
 282   unsigned s;                           /* Current state in exchange */
 283   sel_timer t;                          /* Timer for next exchange */
 284   mp *alpha;                            /* My temporary secret */
 285   ge *c;                                /* My challenge */
 286   ge *rx;                               /* The expected response */
 287   unsigned nr;                          /* Number of extant responses */
 288   time_t t_valid;                       /* When this exchange goes bad */
 289   octet hc[MAXHASHSZ];                  /* Hash of my challenge */
 290   kxchal *r[KX_NCHAL];                  /* Array of challenges */
 291 } keyexch;
 292
 293 #define KXF_TIMER 1u                    /* Waiting for a timer to go off */
 294 #define KXF_DEAD 2u                     /* The key-exchanger isn't up */
 295 #define KXF_PUBKEY 4u                   /* Key exchanger has a public key */
 296 #define KXF_CORK 8u                     /* Don't send anything yet */
 297
 298 enum {
 299   KXS_DEAD,                             /* Uninitialized state (magical) */
 300   KXS_CHAL,                             /* Main answer-challenges state */
 301   KXS_COMMIT,                           /* Committed: send switch request */
 302   KXS_SWITCH                            /* Switched: send confirmation */
 303 };
 304
 305 /* --- Tunnel structure --- *
 306  *
 307  * Used to maintain system-specific information about the tunnel interface.
 308  */
 309
 310 typedef struct tunnel tunnel;
 311 struct peer;
 312
 313 typedef struct tunnel_ops {
 314   const char *name;                     /* Name of this tunnel driver */
 315   unsigned flags;                       /* Various interesting flags */
 316 #define TUNF_PRIVOPEN 1u                /*   Need helper to open file */
 317   void (*init)(void);                   /* Initializes the system */
 318   tunnel *(*create)(struct peer */*p*/, int /*fd*/, char **/*ifn*/);
 319                                         /* Initializes a new tunnel */
 320   void (*setifname)(tunnel */*t*/, const char */*ifn*/);
 321                                         /*  Notifies ifname change */
 322   void (*inject)(tunnel */*t*/, buf */*b*/); /* Sends packet through if */
 323   void (*destroy)(tunnel */*t*/);       /* Destroys a tunnel */
 324 } tunnel_ops;
 325
 326 #ifndef TUN_INTERNALS
 327 struct tunnel { const tunnel_ops *ops; };
 328 #endif
 329
 330 /* --- Peer statistics --- *
 331  *
 332  * Contains various interesting and not-so-interesting statistics about a
 333  * peer.  This is updated by various parts of the code.  The format of the
 334  * structure isn't considered private, and @p_stats@ returns a pointer to the
 335  * statistics block for a given peer.
 336  */
 337
 338 typedef struct stats {
 339   unsigned long sz_in, sz_out;          /* Size of all data in and out */
 340   unsigned long sz_kxin, sz_kxout;      /* Size of key exchange messages */
 341   unsigned long sz_ipin, sz_ipout;      /* Size of encapsulated IP packets */
 342   time_t t_start, t_last, t_kx;         /* Time peer created, last pk, kx */
 343   unsigned long n_reject;               /* Number of rejected packets */
 344   unsigned long n_in, n_out;            /* Number of packets in and out */
 345   unsigned long n_kxin, n_kxout;        /* Number of key exchange packets */
 346   unsigned long n_ipin, n_ipout;        /* Number of encrypted packets */
 347 } stats;
 348
 349 /* --- Peer structure --- *
 350  *
 351  * The main structure which glues everything else together.
 352  */
 353
 354 typedef struct peerspec {
 355   char *name;                           /* Peer's name */
 356   char *privtag;                        /* Private key tag */
 357   char *tag;                            /* Public key tag */
 358   const tunnel_ops *tops;               /* Tunnel operations */
 359   unsigned long t_ka;                   /* Keep alive interval */
 360   addr sa;                              /* Socket address to speak to */
 361   size_t sasz;                          /* Socket address size */
 362   unsigned f;                           /* Flags for the peer */
 363 #define PSF_KXMASK 255u                 /*   Key-exchange flags to set */
 364 #define PSF_MOBILE 256u                 /*   Address may change rapidly */
 365 } peerspec;
 366
 367 typedef struct peer_byname {
 368   sym_base _b;
 369   struct peer *p;
 370 } peer_byname;
 371
 372 typedef struct peer_byaddr {
 373   addrmap_base _b;
 374   struct peer *p;
 375 } peer_byaddr;
 376
 377 typedef struct peer {
 378   peer_byname *byname;                  /* Lookup-by-name block */
 379   peer_byaddr *byaddr;                  /* Lookup-by-address block */
 380   struct ping *pings;                   /* Pings we're waiting for */
 381   peerspec spec;                        /* Specifications for this peer */
 382   tunnel *t;                            /* Tunnel for local packets */
 383   char *ifname;                         /* Interface name for tunnel */
 384   keyset *ks;                           /* List head for keysets */
 385   buf b;                                /* Buffer for sending packets */
 386   stats st;                             /* Statistics */
 387   keyexch kx;                           /* Key exchange protocol block */
 388   sel_timer tka;                        /* Timer for keepalives */
 389 } peer;
 390
 391 typedef struct peer_iter { sym_iter i; } peer_iter;
 392
 393 typedef struct ping {
 394   struct ping *next, *prev;             /* Links to next and previous */
 395   peer *p;                              /* Peer so we can free it */
 396   unsigned msg;                         /* Kind of response expected */
 397   uint32 id;                            /* Id so we can recognize response */
 398   octet magic[32];                      /* Some random data */
 399   sel_timer t;                          /* Timeout for ping */
 400   void (*func)(int /*rc*/, void */*arg*/); /* Function to call when done */
 401   void *arg;                            /* Argument for callback */
 402 } ping;
 403
 404 enum {
 405   PING_NONOTIFY = -1,
 406   PING_OK = 0,
 407   PING_TIMEOUT,
 408   PING_PEERDIED,
 409   PING_MAX
 410 };
 411
 412 /* --- Admin structure --- */
 413
 414 #define OBUFSZ 16384u
 415
 416 typedef struct obuf {
 417   struct obuf *next;                    /* Next buffer in list */
 418   char *p_in, *p_out;                   /* Pointers into the buffer */
 419   char buf[OBUFSZ];                     /* The actual buffer */
 420 } obuf;
 421
 422 typedef struct oqueue {
 423   obuf *hd, *tl;                        /* Head and tail pointers */
 424 } oqueue;
 425
 426 struct admin;
 427
 428 typedef struct admin_bgop {
 429   struct admin_bgop *next, *prev;       /* Links to next and previous */
 430   struct admin *a;                      /* Owner job */
 431   char *tag;                            /* Tag string for messages */
 432   void (*cancel)(struct admin_bgop *);  /* Destructor function */
 433 } admin_bgop;
 434
 435 typedef struct admin_resop {
 436   admin_bgop bg;                        /* Background operation header */
 437   char *addr;                           /* Hostname to be resolved */
 438   bres_client r;                        /* Background resolver task */
 439   sel_timer t;                          /* Timer for resolver */
 440   addr sa;                              /* Socket address */
 441   size_t sasz;                          /* Socket address size */
 442   void (*func)(struct admin_resop *, int); /* Handler */
 443 } admin_resop;
 444
 445 enum { ARES_OK, ARES_FAIL };
 446
 447 typedef struct admin_addop {
 448   admin_resop r;                        /* Name resolution header */
 449   peerspec peer;                        /* Peer pending creation */
 450 } admin_addop;
 451
 452 typedef struct admin_pingop {
 453   admin_bgop bg;                        /* Background operation header */
 454   ping ping;                            /* Ping pending response */
 455   struct timeval pingtime;              /* Time last ping was sent */
 456 } admin_pingop;
 457
 458 typedef struct admin_service {
 459   sym_base _b;                          /* Hash table base structure */
 460   char *version;                        /* The provided version */
 461   struct admin *prov;                   /* Which client provides me */
 462   struct admin_service *next, *prev;    /* Client's list of services */
 463 } admin_service;
 464
 465 typedef struct admin_svcop {
 466   admin_bgop bg;                        /* Background operation header */
 467   struct admin *prov;                   /* Client servicing this job */
 468   unsigned index;                       /* This job's index */
 469   struct admin_svcop *next, *prev;      /* Links for provider's jobs */
 470 } admin_svcop;
 471
 472 typedef struct admin_jobentry {
 473   unsigned short seq;                   /* Zero if unused */
 474   union {
 475     admin_svcop *op;                    /* Operation, if slot in use, ... */
 476     uint32 next;                        /* ... or index of next free slot */
 477   } u;
 478 } admin_jobentry;
 479
 480 typedef struct admin_jobtable {
 481   uint32 n, sz;                         /* Used slots and table size */
 482   admin_svcop *active;                  /* List of active jobs */
 483   uint32 free;                          /* Index of first free slot */
 484   admin_jobentry *v;                    /* And the big array of entries */
 485 } admin_jobtable;
 486
 487 typedef struct admin {
 488   struct admin *next, *prev;            /* Links to next and previous */
 489   unsigned f;                           /* Various useful flags */
 490   unsigned ref;                         /* Reference counter */
 491 #ifndef NTRACE
 492   unsigned seq;                         /* Sequence number for tracing */
 493 #endif
 494   oqueue out;                           /* Output buffer list */
 495   oqueue delay;                         /* Delayed output buffer list */
 496   admin_bgop *bg;                       /* Backgrounded operations */
 497   admin_service *svcs;                  /* Which services I provide */
 498   admin_jobtable j;                     /* Table of outstanding jobs */
 499   selbuf b;                             /* Line buffer for commands */
 500   sel_file w;                           /* Selector for write buffering */
 501 } admin;
 502
 503 #define AF_DEAD 1u                      /* Destroy this admin block */
 504 #define AF_CLOSE 2u                     /* Client closed connection */
 505 #define AF_NOTE 4u                      /* Catch notifications */
 506 #define AF_WARN 8u                      /* Catch warning messages */
 507 #ifndef NTRACE
 508   #define AF_TRACE 16u                  /* Catch tracing */
 509 #endif
 510 #define AF_FOREGROUND 32u               /* Quit server when client closes */
 511
 512 #ifndef NTRACE
 513 #  define AF_ALLMSGS (AF_NOTE | AF_TRACE | AF_WARN)
 514 #else
 515 #  define AF_ALLMSGS (AF_NOTE | AF_WARN)
 516 #endif
 517
 518 /*----- Global variables --------------------------------------------------*/
 519
 520 extern sel_state sel;                   /* Global I/O event state */
 521 extern octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ], buf_u[PKBUFSZ];
 522 extern const tunnel_ops *tunnels[];     /* Table of tunnels (0-term) */
 523 extern const tunnel_ops *tun_default;   /* Default tunnel to use */
 524 extern kdata *master;                   /* Default private key */
 525 extern const char *tag_priv;            /* Default private key tag */
 526
 527 #ifndef NTRACE
 528 extern const trace_opt tr_opts[];       /* Trace options array */
 529 extern unsigned tr_flags;               /* Trace options flags */
 530 #endif
 531
 532 /*----- Other macros ------------------------------------------------------*/
 533
 534 #define TIMER noise_timer(RAND_GLOBAL)
 535
 536 /*----- Key management ----------------------------------------------------*/
 537
 538 /* --- @km_init@ --- *
 539  *
 540  * Arguments:   @const char *privkr@ = private keyring file
 541  *              @const char *pubkr@ = public keyring file
 542  *              @const char *ptag@ = default private-key tag
 543  *
 544  * Returns:     ---
 545  *
 546  * Use:         Initializes the key-management machinery, loading the
 547  *              keyrings and so on.
 548  */
 549
 550 extern void km_init(const char */*privkr*/, const char */*pubkr*/,
 551                     const char */*ptag*/);
 552
 553 /* --- @km_reload@ --- *
 554  *
 555  * Arguments:   ---
 556  *
 557  * Returns:     Zero if OK, nonzero to force reloading of keys.
 558  *
 559  * Use:         Checks the keyrings to see if they need reloading.
 560  */
 561
 562 extern int km_reload(void);
 563
 564 /* --- @km_findpub@, @km_findpriv@ --- *
 565  *
 566  * Arguments:   @const char *tag@ = key tag to load
 567  *
 568  * Returns:     Pointer to the kdata object if successful, or null on error.
 569  *
 570  * Use:         Fetches a public or private key from the keyring.
 571  */
 572
 573 extern kdata *km_findpub(const char */*tag*/);
 574 extern kdata *km_findpriv(const char */*tag*/);
 575
 576 /* --- @km_samealgsp@ --- *
 577  *
 578  * Arguments:   @const kdata *kdx, *kdy@ = two key data objects
 579  *
 580  * Returns:     Nonzero if their two algorithm selections are the same.
 581  *
 582  * Use:         Checks sameness of algorithm selections: used to ensure that
 583  *              peers are using sensible algorithms.
 584  */
 585
 586 extern int km_samealgsp(const kdata */*kdx*/, const kdata */*kdy*/);
 587
 588 /* --- @km_ref@ --- *
 589  *
 590  * Arguments:   @kdata *kd@ = pointer to the kdata object
 591  *
 592  * Returns:     ---
 593  *
 594  * Use:         Claim a new reference to a kdata object.
 595  */
 596
 597 extern void km_ref(kdata */*kd*/);
 598
 599 /* --- @km_unref@ --- *
 600  *
 601  * Arguments:   @kdata *kd@ = pointer to the kdata object
 602  *
 603  * Returns:     ---
 604  *
 605  * Use:         Releases a reference to a kdata object.
 606  */
 607
 608 extern void km_unref(kdata */*kd*/);
 609
 610 /* --- @km_tag@ --- *
 611  *
 612  * Arguments:   @kdata *kd@ - pointer to the kdata object
 613  *
 614  * Returns:     A pointer to the short tag by which the kdata was loaded.
 615  */
 616
 617 extern const char *km_tag(kdata */*kd*/);
 618
 619 /*----- Key exchange ------------------------------------------------------*/
 620
 621 /* --- @kx_start@ --- *
 622  *
 623  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 624  *              @int forcep@ = nonzero to ignore the quiet timer
 625  *
 626  * Returns:     ---
 627  *
 628  * Use:         Stimulates a key exchange.  If a key exchage is in progress,
 629  *              a new challenge is sent (unless the quiet timer forbids
 630  *              this); if no exchange is in progress, one is commenced.
 631  */
 632
 633 extern void kx_start(keyexch */*kx*/, int /*forcep*/);
 634
 635 /* --- @kx_message@ --- *
 636  *
 637  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 638  *              @unsigned msg@ = the message code
 639  *              @buf *b@ = pointer to buffer containing the packet
 640  *
 641  * Returns:     ---
 642  *
 643  * Use:         Reads a packet containing key exchange messages and handles
 644  *              it.
 645  */
 646
 647 extern void kx_message(keyexch */*kx*/, unsigned /*msg*/, buf */*b*/);
 648
 649 /* --- @kx_free@ --- *
 650  *
 651  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 652  *
 653  * Returns:     ---
 654  *
 655  * Use:         Frees everything in a key exchange context.
 656  */
 657
 658 extern void kx_free(keyexch */*kx*/);
 659
 660 /* --- @kx_newkeys@ --- *
 661  *
 662  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 663  *
 664  * Returns:     ---
 665  *
 666  * Use:         Informs the key exchange module that its keys may have
 667  *              changed.  If fetching the new keys fails, the peer will be
 668  *              destroyed, we log messages and struggle along with the old
 669  *              keys.
 670  */
 671
 672 extern void kx_newkeys(keyexch */*kx*/);
 673
 674 /* --- @kx_init@ --- *
 675  *
 676  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 677  *              @peer *p@ = pointer to peer context
 678  *              @keyset **ks@ = pointer to keyset list
 679  *              @unsigned f@ = various useful flags
 680  *
 681  * Returns:     Zero if OK, nonzero if it failed.
 682  *
 683  * Use:         Initializes a key exchange module.  The module currently
 684  *              contains no keys, and will attempt to initiate a key
 685  *              exchange.
 686  */
 687
 688 extern int kx_init(keyexch */*kx*/, peer */*p*/,
 689                    keyset **/*ks*/, unsigned /*f*/);
 690
 691 /*----- Keysets and symmetric cryptography --------------------------------*/
 692
 693 /* --- @ks_drop@ --- *
 694  *
 695  * Arguments:   @keyset *ks@ = pointer to a keyset
 696  *
 697  * Returns:     ---
 698  *
 699  * Use:         Decrements a keyset's reference counter.  If the counter hits
 700  *              zero, the keyset is freed.
 701  */
 702
 703 extern void ks_drop(keyset */*ks*/);
 704
 705 /* --- @ks_gen@ --- *
 706  *
 707  * Arguments:   @const void *k@ = pointer to key material
 708  *              @size_t x, y, z@ = offsets into key material (see below)
 709  *              @peer *p@ = pointer to peer information
 710  *
 711  * Returns:     A pointer to the new keyset.
 712  *
 713  * Use:         Derives a new keyset from the given key material.  The
 714  *              offsets @x@, @y@ and @z@ separate the key material into three
 715  *              parts.  Between the @k@ and @k + x@ is `my' contribution to
 716  *              the key material; between @k + x@ and @k + y@ is `your'
 717  *              contribution; and between @k + y@ and @k + z@ is a shared
 718  *              value we made together.  These are used to construct two
 719  *              pairs of symmetric keys.  Each pair consists of an encryption
 720  *              key and a message authentication key.  One pair is used for
 721  *              outgoing messages, the other for incoming messages.
 722  *
 723  *              The new key is marked so that it won't be selected for output
 724  *              by @ksl_encrypt@.  You can still encrypt data with it by
 725  *              calling @ks_encrypt@ directly.
 726  */
 727
 728 extern keyset *ks_gen(const void */*k*/,
 729                       size_t /*x*/, size_t /*y*/, size_t /*z*/,
 730                       peer */*p*/);
 731
 732 /* --- @ks_tregen@ --- *
 733  *
 734  * Arguments:   @keyset *ks@ = pointer to a keyset
 735  *
 736  * Returns:     The time at which moves ought to be made to replace this key.
 737  */
 738
 739 extern time_t ks_tregen(keyset */*ks*/);
 740
 741 /* --- @ks_activate@ --- *
 742  *
 743  * Arguments:   @keyset *ks@ = pointer to a keyset
 744  *
 745  * Returns:     ---
 746  *
 747  * Use:         Activates a keyset, so that it can be used for encrypting
 748  *              outgoing messages.
 749  */
 750
 751 extern void ks_activate(keyset */*ks*/);
 752
 753 /* --- @ks_encrypt@ --- *
 754  *
 755  * Arguments:   @keyset *ks@ = pointer to a keyset
 756  *              @unsigned ty@ = message type
 757  *              @buf *b@ = pointer to input buffer
 758  *              @buf *bb@ = pointer to output buffer
 759  *
 760  * Returns:     Zero if successful; @KSERR_REGEN@ if we should negotiate a
 761  *              new key; @KSERR_NOKEYS@ if the key is not usable.  Also
 762  *              returns zero if there was insufficient buffer (but the output
 763  *              buffer is broken in this case).
 764  *
 765  * Use:         Encrypts a block of data using the key.  Note that the `key
 766  *              ought to be replaced' notification is only ever given once
 767  *              for each key.  Also note that this call forces a keyset to be
 768  *              used even if it's marked as not for data output.
 769  */
 770
 771 extern int ks_encrypt(keyset */*ks*/, unsigned /*ty*/,
 772                       buf */*b*/, buf */*bb*/);
 773
 774 /* --- @ks_decrypt@ --- *
 775  *
 776  * Arguments:   @keyset *ks@ = pointer to a keyset
 777  *              @unsigned ty@ = expected type code
 778  *              @buf *b@ = pointer to an input buffer
 779  *              @buf *bb@ = pointer to an output buffer
 780  *
 781  * Returns:     Zero on success; @KSERR_DECRYPT@ on failure.  Also returns
 782  *              zero if there was insufficient buffer (but the output buffer
 783  *              is broken in this case).
 784  *
 785  * Use:         Attempts to decrypt a message using a given key.  Note that
 786  *              requesting decryption with a key directly won't clear a
 787  *              marking that it's not for encryption.
 788  */
 789
 790 extern int ks_decrypt(keyset */*ks*/, unsigned /*ty*/,
 791                       buf */*b*/, buf */*bb*/);
 792
 793 /* --- @ksl_free@ --- *
 794  *
 795  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 796  *
 797  * Returns:     ---
 798  *
 799  * Use:         Frees (releases references to) all of the keys in a keyset.
 800  */
 801
 802 extern void ksl_free(keyset **/*ksroot*/);
 803
 804 /* --- @ksl_link@ --- *
 805  *
 806  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 807  *              @keyset *ks@ = pointer to a keyset
 808  *
 809  * Returns:     ---
 810  *
 811  * Use:         Links a keyset into a list.  A keyset can only be on one list
 812  *              at a time.  Bad things happen otherwise.
 813  */
 814
 815 extern void ksl_link(keyset **/*ksroot*/, keyset */*ks*/);
 816
 817 /* --- @ksl_prune@ --- *
 818  *
 819  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 820  *
 821  * Returns:     ---
 822  *
 823  * Use:         Prunes the keyset list by removing keys which mustn't be used
 824  *              any more.
 825  */
 826
 827 extern void ksl_prune(keyset **/*ksroot*/);
 828
 829 /* --- @ksl_encrypt@ --- *
 830  *
 831  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 832  *              @unsigned ty@ = message type
 833  *              @buf *b@ = pointer to input buffer
 834  *              @buf *bb@ = pointer to output buffer
 835  *
 836  * Returns:     Zero if successful; @KSERR_REGEN@ if it's time to negotiate a
 837  *              new key; @KSERR_NOKEYS@ if there are no suitable keys
 838  *              available.  Also returns zero if there was insufficient
 839  *              buffer space (but the output buffer is broken in this case).
 840  *
 841  * Use:         Encrypts a packet.
 842  */
 843
 844 extern int ksl_encrypt(keyset **/*ksroot*/, unsigned /*ty*/,
 845                        buf */*b*/, buf */*bb*/);
 846
 847 /* --- @ksl_decrypt@ --- *
 848  *
 849  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 850  *              @unsigned ty@ = expected type code
 851  *              @buf *b@ = pointer to input buffer
 852  *              @buf *bb@ = pointer to output buffer
 853  *
 854  * Returns:     Zero on success; @KSERR_DECRYPT@ on failure.  Also returns
 855  *              zero if there was insufficient buffer (but the output buffer
 856  *              is broken in this case).
 857  *
 858  * Use:         Decrypts a packet.
 859  */
 860
 861 extern int ksl_decrypt(keyset **/*ksroot*/, unsigned /*ty*/,
 862                        buf */*b*/, buf */*bb*/);
 863
 864 /*----- Challenges --------------------------------------------------------*/
 865
 866 /* --- @c_new@ --- *
 867  *
 868  * Arguments:   @buf *b@ = where to put the challenge
 869  *
 870  * Returns:     Zero if OK, nonzero on error.
 871  *
 872  * Use:         Issues a new challenge.
 873  */
 874
 875 extern int c_new(buf */*b*/);
 876
 877 /* --- @c_check@ --- *
 878  *
 879  * Arguments:   @buf *b@ = where to find the challenge
 880  *
 881  * Returns:     Zero if OK, nonzero if it didn't work.
 882  *
 883  * Use:         Checks a challenge.  On failure, the buffer is broken.
 884  */
 885
 886 extern int c_check(buf */*b*/);
 887
 888 /*----- Administration interface ------------------------------------------*/
 889
 890 #define A_END ((char *)0)
 891
 892 /* --- @a_vformat@ --- *
 893  *
 894  * Arguments:   @dstr *d@ = where to leave the formatted message
 895  *              @const char *fmt@ = pointer to format string
 896  *              @va_list ap@ = arguments in list
 897  *
 898  * Returns:     ---
 899  *
 900  * Use:         Main message token formatting driver.  The arguments are
 901  *              interleaved formatting tokens and their parameters, finally
 902  *              terminated by an entry @A_END@.
 903  *
 904  *              Tokens recognized:
 905  *
 906  *                * "*..." ... -- pretokenized @dstr_putf@-like string
 907  *
 908  *                * "?ADDR" SOCKADDR -- a socket address, to be converted
 909  *
 910  *                * "?B64" BUFFER SIZE -- binary data to be base64-encoded
 911  *
 912  *                * "?TOKENS" VECTOR -- null-terminated vector of tokens
 913  *
 914  *                * "?PEER" PEER -- peer's name
 915  *
 916  *                * "?ERRNO" ERRNO -- system error code
 917  *
 918  *                * "[!]..." ... -- @dstr_putf@-like string as single token
 919  */
 920
 921 extern void a_vformat(dstr */*d*/, const char */*fmt*/, va_list /*ap*/);
 922
 923 /* --- @a_format@ --- *
 924  *
 925  * Arguments:   @dstr *d@ = where to leave the formatted message
 926  *              @const char *fmt@ = pointer to format string
 927  *
 928  * Returns:     ---
 929  *
 930  * Use:         Writes a tokenized message into a string, for later
 931  *              presentation.
 932  */
 933
 934 extern void a_format(dstr */*d*/, const char */*fmt*/, ...);
 935
 936 /* --- @a_warn@ --- *
 937  *
 938  * Arguments:   @const char *fmt@ = pointer to format string
 939  *              @...@ = other arguments
 940  *
 941  * Returns:     ---
 942  *
 943  * Use:         Informs all admin connections of a warning.
 944  */
 945
 946 extern void a_warn(const char */*fmt*/, ...);
 947
 948 /* --- @a_notify@ --- *
 949  *
 950  * Arguments:   @const char *fmt@ = pointer to format string
 951  *              @...@ = other arguments
 952  *
 953  * Returns:     ---
 954  *
 955  * Use:         Sends a notification to interested admin connections.
 956  */
 957
 958 extern void a_notify(const char */*fmt*/, ...);
 959
 960 /* --- @a_create@ --- *
 961  *
 962  * Arguments:   @int fd_in, fd_out@ = file descriptors to use
 963  *              @unsigned f@ = initial flags to set
 964  *
 965  * Returns:     ---
 966  *
 967  * Use:         Creates a new admin connection.
 968  */
 969
 970 extern void a_create(int /*fd_in*/, int /*fd_out*/, unsigned /*f*/);
 971
 972 /* --- @a_quit@ --- *
 973  *
 974  * Arguments:   ---
 975  *
 976  * Returns:     ---
 977  *
 978  * Use:         Shuts things down nicely.
 979  */
 980
 981 extern void a_quit(void);
 982
 983 /* --- @a_preselect@ --- *
 984  *
 985  * Arguments:   ---
 986  *
 987  * Returns:     ---
 988  *
 989  * Use:         Informs the admin module that we're about to select again,
 990  *              and that it should do cleanup things it has delayed until a
 991  *              `safe' time.
 992  */
 993
 994 extern void a_preselect(void);
 995
 996 /* --- @a_daemon@ --- *
 997  *
 998  * Arguments:   ---
 999  *
1000  * Returns:     ---
1001  *
1002  * Use:         Informs the admin module that it's a daemon.
1003  */
1004
1005 extern void a_daemon(void);
1006
1007 /* --- @a_init@ --- *
1008  *
1009  * Arguments:   @const char *sock@ = socket name to create
1010  *              @uid_t u@ = user to own the socket
1011  *              @gid_t g@ = group to own the socket
1012  *              @mode_t m@ = permissions to set on the socket
1013  *
1014  * Returns:     ---
1015  *
1016  * Use:         Creates the admin listening socket.
1017  */
1018
1019 extern void a_init(const char */*sock*/,
1020                    uid_t /*u*/, gid_t /*g*/, mode_t /*m*/);
1021
1022 /*----- Mapping with addresses as keys ------------------------------------*/
1023
1024 /* --- @am_create@ --- *
1025  *
1026  * Arguments:   @addrmap *m@ = pointer to map
1027  *
1028  * Returns:     ---
1029  *
1030  * Use:         Create an address map, properly set up.
1031  */
1032
1033 extern void am_create(addrmap */*m*/);
1034
1035 /* --- @am_destroy@ --- *
1036  *
1037  * Arguments:   @addrmap *m@ = pointer to map
1038  *
1039  * Returns:     ---
1040  *
1041  * Use:         Destroy an address map, throwing away all the entries.
1042  */
1043
1044 extern void am_destroy(addrmap */*m*/);
1045
1046 /* --- @am_find@ --- *
1047  *
1048  * Arguments:   @addrmap *m@ = pointer to map
1049  *              @const addr *a@ = address to look up
1050  *              @size_t sz@ = size of block to allocate
1051  *              @unsigned *f@ = where to store flags
1052  *
1053  * Returns:     Pointer to found item, or null.
1054  *
1055  * Use:         Finds a record with the given IP address, set @*f@ nonzero
1056  *              and returns it.  If @sz@ is zero, and no match was found,
1057  *              return null; otherwise allocate a new block of @sz@ bytes,
1058  *              clear @*f@ to zero and return the block pointer.
1059  */
1060
1061 extern void *am_find(addrmap */*m*/, const addr */*a*/,
1062                      size_t /*sz*/, unsigned */*f*/);
1063
1064 /* --- @am_remove@ --- *
1065  *
1066  * Arguments:   @addrmap *m@ = pointer to map
1067  *              @void *i@ = pointer to the item
1068  *
1069  * Returns:     ---
1070  *
1071  * Use:         Removes an item from the map.
1072  */
1073
1074 extern void am_remove(addrmap */*m*/, void */*i*/);
1075
1076 /*----- Privilege separation ----------------------------------------------*/
1077
1078 /* --- @ps_trace@ --- *
1079  *
1080  * Arguments:   @unsigned mask@ = trace mask to check
1081  *              @const char *fmt@ = message format
1082  *              @...@ = values for placeholders
1083  *
1084  * Returns:     ---
1085  *
1086  * Use:         Writes a trace message.
1087  */
1088
1089 T( extern void ps_trace(unsigned /*mask*/, const char */*fmt*/, ...); )
1090
1091 /* --- @ps_warn@ --- *
1092  *
1093  * Arguments:   @const char *fmt@ = message format
1094  *              @...@ = values for placeholders
1095  *
1096  * Returns:     ---
1097  *
1098  * Use:         Writes a warning message.
1099  */
1100
1101 extern void ps_warn(const char */*fmt*/, ...);
1102
1103 /* --- @ps_tunfd@ --- *
1104  *
1105  * Arguments:   @const tunnel_ops *tops@ = pointer to tunnel operations
1106  *              @char **ifn@ = where to put the interface name
1107  *
1108  * Returns:     The file descriptor, or @-1@ on error.
1109  *
1110  * Use:         Fetches a file descriptor for a tunnel driver.
1111  */
1112
1113 extern int ps_tunfd(const tunnel_ops */*tops*/, char **/*ifn*/);
1114
1115 /* --- @ps_split@ --- *
1116  *
1117  * Arguments:   @int detachp@ = whether to detach the child from its terminal
1118  *
1119  * Returns:     ---
1120  *
1121  * Use:         Separates off the privileged tunnel-opening service from the
1122  *              rest of the server.
1123  */
1124
1125 extern void ps_split(int /*detachp*/);
1126
1127 /* --- @ps_quit@ --- *
1128  *
1129  * Arguments:   ---
1130  *
1131  * Returns:     ---
1132  *
1133  * Use:         Detaches from the helper process.
1134  */
1135
1136 extern void ps_quit(void);
1137
1138 /*----- Peer management ---------------------------------------------------*/
1139
1140 /* --- @p_txstart@ --- *
1141  *
1142  * Arguments:   @peer *p@ = pointer to peer block
1143  *              @unsigned msg@ = message type code
1144  *
1145  * Returns:     A pointer to a buffer to write to.
1146  *
1147  * Use:         Starts sending to a peer.  Only one send can happen at a
1148  *              time.
1149  */
1150
1151 extern buf *p_txstart(peer */*p*/, unsigned /*msg*/);
1152
1153 /* --- @p_txend@ --- *
1154  *
1155  * Arguments:   @peer *p@ = pointer to peer block
1156  *
1157  * Returns:     ---
1158  *
1159  * Use:         Sends a packet to the peer.
1160  */
1161
1162 extern void p_txend(peer */*p*/);
1163
1164 /* --- @p_pingsend@ --- *
1165  *
1166  * Arguments:   @peer *p@ = destination peer
1167  *              @ping *pg@ = structure to fill in
1168  *              @unsigned type@ = message type
1169  *              @unsigned long timeout@ = how long to wait before giving up
1170  *              @void (*func)(int, void *)@ = callback function
1171  *              @void *arg@ = argument for callback
1172  *
1173  * Returns:     Zero if successful, nonzero if it failed.
1174  *
1175  * Use:         Sends a ping to a peer.  Call @func@ with a nonzero argument
1176  *              if we get an answer within the timeout, or zero if no answer.
1177  */
1178
1179 extern int p_pingsend(peer */*p*/, ping */*pg*/, unsigned /*type*/,
1180                       unsigned long /*timeout*/,
1181                       void (*/*func*/)(int, void *), void */*arg*/);
1182
1183 /* --- @p_pingdone@ --- *
1184  *
1185  * Arguments:   @ping *p@ = ping structure
1186  *              @int rc@ = return code to pass on
1187  *
1188  * Returns:     ---
1189  *
1190  * Use:         Disposes of a ping structure, maybe sending a notification.
1191  */
1192
1193 extern void p_pingdone(ping */*p*/, int /*rc*/);
1194
1195 /* --- @p_greet@ --- *
1196  *
1197  * Arguments:   @peer *p@ = peer to send to
1198  *              @const void *c@ = pointer to challenge
1199  *              @size_t sz@ = size of challenge
1200  *
1201  * Returns:     ---
1202  *
1203  * Use:         Sends a greeting packet.
1204  */
1205
1206 extern void p_greet(peer */*p*/, const void */*c*/, size_t /*sz*/);
1207
1208 /* --- @p_tun@ --- *
1209  *
1210  * Arguments:   @peer *p@ = pointer to peer block
1211  *              @buf *b@ = buffer containing incoming packet
1212  *
1213  * Returns:     ---
1214  *
1215  * Use:         Handles a packet which needs to be sent to a peer.
1216  */
1217
1218 extern void p_tun(peer */*p*/, buf */*b*/);
1219
1220 /* --- @p_keyreload@ --- *
1221  *
1222  * Arguments:   ---
1223  *
1224  * Returns:     ---
1225  *
1226  * Use:         Forces a check of the daemon's keyring files.
1227  */
1228
1229 extern void p_keyreload(void);
1230
1231 /* --- @p_interval@ --- *
1232  *
1233  * Arguments:   ---
1234  *
1235  * Returns:     ---
1236  *
1237  * Use:         Called periodically to do tidying.
1238  */
1239
1240 extern void p_interval(void);
1241
1242 /* --- @p_stats@ --- *
1243  *
1244  * Arguments:   @peer *p@ = pointer to a peer block
1245  *
1246  * Returns:     A pointer to the peer's statistics.
1247  */
1248
1249 extern stats *p_stats(peer */*p*/);
1250
1251 /* --- @p_ifname@ --- *
1252  *
1253  * Arguments:   @peer *p@ = pointer to a peer block
1254  *
1255  * Returns:     A pointer to the peer's interface name.
1256  */
1257
1258 extern const char *p_ifname(peer */*p*/);
1259
1260 /* --- @p_setifname@ --- *
1261  *
1262  * Arguments:   @peer *p@ = pointer to a peer block
1263  *              @const char *name@ = pointer to the new name
1264  *
1265  * Returns:     ---
1266  *
1267  * Use:         Changes the name held for a peer's interface.
1268  */
1269
1270 extern void p_setifname(peer */*p*/, const char */*name*/);
1271
1272 /* --- @p_addr@ --- *
1273  *
1274  * Arguments:   @peer *p@ = pointer to a peer block
1275  *
1276  * Returns:     A pointer to the peer's address.
1277  */
1278
1279 extern const addr *p_addr(peer */*p*/);
1280
1281 /* --- @p_init@ --- *
1282  *
1283  * Arguments:   @struct in_addr addr@ = address to bind to
1284  *              @unsigned port@ = port number to listen to
1285  *
1286  * Returns:     ---
1287  *
1288  * Use:         Initializes the peer system; creates the socket.
1289  */
1290
1291 extern void p_init(struct in_addr /*addr*/, unsigned /*port*/);
1292
1293 /* --- @p_port@ --- *
1294  *
1295  * Arguments:   ---
1296  *
1297  * Returns:     Port number used for socket.
1298  */
1299
1300 unsigned p_port(void);
1301
1302 /* --- @p_create@ --- *
1303  *
1304  * Arguments:   @peerspec *spec@ = information about this peer
1305  *
1306  * Returns:     Pointer to the peer block, or null if it failed.
1307  *
1308  * Use:         Creates a new named peer block.  No peer is actually attached
1309  *              by this point.
1310  */
1311
1312 extern peer *p_create(peerspec */*spec*/);
1313
1314 /* --- @p_name@ --- *
1315  *
1316  * Arguments:   @peer *p@ = pointer to a peer block
1317  *
1318  * Returns:     A pointer to the peer's name.
1319  *
1320  * Use:         Equivalent to @p_spec(p)->name@.
1321  */
1322
1323 extern const char *p_name(peer */*p*/);
1324
1325 /* --- @p_tag@ --- *
1326  *
1327  * Arguments:   @peer *p@ = pointer to a peer block
1328  *
1329  * Returns:     A pointer to the peer's public key tag.
1330  */
1331
1332 extern const char *p_tag(peer */*p*/);
1333
1334 /* --- @p_privtag@ --- *
1335  *
1336  * Arguments:   @peer *p@ = pointer to a peer block
1337  *
1338  * Returns:     A pointer to the peer's private key tag.
1339  */
1340
1341 extern const char *p_privtag(peer */*p*/);
1342
1343 /* --- @p_spec@ --- *
1344  *
1345  * Arguments:   @peer *p@ = pointer to a peer block
1346  *
1347  * Returns:     Pointer to the peer's specification
1348  */
1349
1350 extern const peerspec *p_spec(peer */*p*/);
1351
1352 /* --- @p_findbyaddr@ --- *
1353  *
1354  * Arguments:   @const addr *a@ = address to look up
1355  *
1356  * Returns:     Pointer to the peer block, or null if not found.
1357  *
1358  * Use:         Finds a peer by address.
1359  */
1360
1361 extern peer *p_findbyaddr(const addr */*a*/);
1362
1363 /* --- @p_find@ --- *
1364  *
1365  * Arguments:   @const char *name@ = name to look up
1366  *
1367  * Returns:     Pointer to the peer block, or null if not found.
1368  *
1369  * Use:         Finds a peer by name.
1370  */
1371
1372 extern peer *p_find(const char */*name*/);
1373
1374 /* --- @p_destroy@ --- *
1375  *
1376  * Arguments:   @peer *p@ = pointer to a peer
1377  *
1378  * Returns:     ---
1379  *
1380  * Use:         Destroys a peer.
1381  */
1382
1383 extern void p_destroy(peer */*p*/);
1384
1385 /* --- @FOREACH_PEER@ --- *
1386  *
1387  * Arguments:   @p@ = name to bind to each peer
1388  *              @stuff@ = thing to do for each item
1389  *
1390  * Use:         Does something for each current peer.
1391  */
1392
1393 #define FOREACH_PEER(p, stuff) do {                                     \
1394   peer_iter i_;                                                         \
1395   peer *p;                                                              \
1396   for (p_mkiter(&i_); (p = p_next(&i_)) != 0; ) stuff                   \
1397 } while (0)
1398
1399 /* --- @p_mkiter@ --- *
1400  *
1401  * Arguments:   @peer_iter *i@ = pointer to an iterator
1402  *
1403  * Returns:     ---
1404  *
1405  * Use:         Initializes the iterator.
1406  */
1407
1408 extern void p_mkiter(peer_iter */*i*/);
1409
1410 /* --- @p_next@ --- *
1411  *
1412  * Arguments:   @peer_iter *i@ = pointer to an iterator
1413  *
1414  * Returns:     Next peer, or null if at the end.
1415  *
1416  * Use:         Returns the next peer.
1417  */
1418
1419 extern peer *p_next(peer_iter */*i*/);
1420
1421 /*----- Tunnel drivers ----------------------------------------------------*/
1422
1423 #ifdef TUN_LINUX
1424   extern const tunnel_ops tun_linux;
1425 #endif
1426
1427 #ifdef TUN_UNET
1428   extern const tunnel_ops tun_unet;
1429 #endif
1430
1431 #ifdef TUN_BSD
1432   extern const tunnel_ops tun_bsd;
1433 #endif
1434
1435 extern const tunnel_ops tun_slip;
1436
1437 /*----- Other handy utilities ---------------------------------------------*/
1438
1439 /* --- @mpstr@ --- *
1440  *
1441  * Arguments:   @mp *m@ = a multiprecision integer
1442  *
1443  * Returns:     A pointer to the integer's textual representation.
1444  *
1445  * Use:         Converts a multiprecision integer to a string.  Corrupts
1446  *              @buf_u@.
1447  */
1448
1449 extern const char *mpstr(mp */*m*/);
1450
1451 /* --- @gestr@ --- *
1452  *
1453  * Arguments:   @group *g@ = a group
1454  *              @ge *x@ = a group element
1455  *
1456  * Returns:     A pointer to the element's textual representation.
1457  *
1458  * Use:         Converts a group element to a string.  Corrupts
1459  *              @buf_u@.
1460  */
1461
1462 extern const char *gestr(group */*g*/, ge */*x*/);
1463
1464 /* --- @timestr@ --- *
1465  *
1466  * Arguments:   @time_t t@ = a time to convert
1467  *
1468  * Returns:     A pointer to a textual representation of the time.
1469  *
1470  * Use:         Converts a time to a textual representation.  Corrupts
1471  *              @buf_u@.
1472  */
1473
1474 extern const char *timestr(time_t /*t*/);
1475
1476 /* --- @mystrieq@ --- *
1477  *
1478  * Arguments:   @const char *x, *y@ = two strings
1479  *
1480  * Returns:     True if @x@ and @y are equal, up to case.
1481  */
1482
1483 extern int mystrieq(const char */*x*/, const char */*y*/);
1484
1485 /* --- @seq_reset@ --- *
1486  *
1487  * Arguments:   @seqwin *s@ = sequence-checking window
1488  *
1489  * Returns:     ---
1490  *
1491  * Use:         Resets a sequence number window.
1492  */
1493
1494 extern void seq_reset(seqwin */*s*/);
1495
1496 /* --- @seq_check@ --- *
1497  *
1498  * Arguments:   @seqwin *s@ = sequence-checking window
1499  *              @uint32 q@ = sequence number to check
1500  *              @const char *service@ = service to report message from
1501  *
1502  * Returns:     A @SEQ_@ code.
1503  *
1504  * Use:         Checks a sequence number against the window, updating things
1505  *              as necessary.
1506  */
1507
1508 extern int seq_check(seqwin */*s*/, uint32 /*q*/, const char */*service*/);
1509
1510 /*----- That's all, folks -------------------------------------------------*/
1511
1512 #ifdef __cplusplus
1513   }
1514 #endif
1515
1516 #endif