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