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 #define KSERR_REGEN -1                  /* Regenerate keys */
 221 #define KSERR_NOKEYS -2                 /* No keys left */
 222 #define KSERR_DECRYPT -3                /* Unable to decrypt message */
 223
 224 /* --- Key exchange --- *
 225  *
 226  * TrIPE uses the Wrestlers Protocol for its key exchange.  The Wrestlers
 227  * Protocol has a number of desirable features (e.g., perfect forward
 228  * secrecy, and zero-knowledge authentication) which make it attractive for
 229  * use in TrIPE.  The Wrestlers Protocol was designed by Mark Wooding and
 230  * Clive Jones.
 231  */
 232
 233 #define KX_NCHAL 16u
 234
 235 typedef struct kxchal {
 236   struct keyexch *kx;                   /* Pointer back to key exchange */
 237   ge *c;                                /* Responder's challenge */
 238   ge *r;                                /* My reply to the challenge */
 239   keyset *ks;                           /* Pointer to temporary keyset */
 240   unsigned f;                           /* Various useful flags */
 241   sel_timer t;                          /* Response timer for challenge */
 242   octet hc[MAXHASHSZ];                  /* Hash of his challenge */
 243   octet ck[MAXHASHSZ];                  /* His magical check value */
 244   octet hswrq_in[MAXHASHSZ];            /* Inbound switch request message */
 245   octet hswok_in[MAXHASHSZ];            /* Inbound switch confirmation */
 246   octet hswrq_out[MAXHASHSZ];           /* Outbound switch request message */
 247   octet hswok_out[MAXHASHSZ];           /* Outbound switch confirmation */
 248 } kxchal;
 249
 250 typedef struct keyexch {
 251   struct peer *p;                       /* Pointer back to the peer */
 252   keyset **ks;                          /* Peer's list of keysets */
 253   unsigned f;                           /* Various useful flags */
 254   unsigned s;                           /* Current state in exchange */
 255   sel_timer t;                          /* Timer for next exchange */
 256   ge *kpub;                             /* Peer's public key */
 257   time_t texp_kpub;                     /* Expiry time for public key */
 258   mp *alpha;                            /* My temporary secret */
 259   ge *c;                                /* My challenge */
 260   ge *rx;                               /* The expected response */
 261   unsigned nr;                          /* Number of extant responses */
 262   time_t t_valid;                       /* When this exchange goes bad */
 263   octet hc[MAXHASHSZ];                  /* Hash of my challenge */
 264   kxchal *r[KX_NCHAL];                  /* Array of challenges */
 265 } keyexch;
 266
 267 #define KXF_TIMER 1u                    /* Waiting for a timer to go off */
 268 #define KXF_DEAD 2u                     /* The key-exchanger isn't up */
 269 #define KXF_PUBKEY 4u                   /* Key exchanger has a public key */
 270 #define KXF_CORK 8u                     /* Don't send anything yet */
 271
 272 enum {
 273   KXS_DEAD,                             /* Uninitialized state (magical) */
 274   KXS_CHAL,                             /* Main answer-challenges state */
 275   KXS_COMMIT,                           /* Committed: send switch request */
 276   KXS_SWITCH                            /* Switched: send confirmation */
 277 };
 278
 279 /* --- Tunnel structure --- *
 280  *
 281  * Used to maintain system-specific information about the tunnel interface.
 282  */
 283
 284 typedef struct tunnel tunnel;
 285 struct peer;
 286
 287 typedef struct tunnel_ops {
 288   const char *name;                     /* Name of this tunnel driver */
 289   void (*init)(void);                   /* Initializes the system */
 290   tunnel *(*create)(struct peer */*p*/, char **/*ifn*/);
 291                                         /* Initializes a new tunnel */
 292   void (*setifname)(tunnel */*t*/, const char */*ifn*/);
 293                                         /*  Notifies ifname change */
 294   void (*inject)(tunnel */*t*/, buf */*b*/); /* Sends packet through if */
 295   void (*destroy)(tunnel */*t*/);       /* Destroys a tunnel */
 296 } tunnel_ops;
 297
 298 #ifndef TUN_INTERNALS
 299 struct tunnel { const tunnel_ops *ops; };
 300 #endif
 301
 302 /* --- Peer statistics --- *
 303  *
 304  * Contains various interesting and not-so-interesting statistics about a
 305  * peer.  This is updated by various parts of the code.  The format of the
 306  * structure isn't considered private, and @p_stats@ returns a pointer to the
 307  * statistics block for a given peer.
 308  */
 309
 310 typedef struct stats {
 311   unsigned long sz_in, sz_out;          /* Size of all data in and out */
 312   unsigned long sz_kxin, sz_kxout;      /* Size of key exchange messages */
 313   unsigned long sz_ipin, sz_ipout;      /* Size of encapsulated IP packets */
 314   time_t t_start, t_last, t_kx;         /* Time peer created, last pk, kx */
 315   unsigned long n_reject;               /* Number of rejected packets */
 316   unsigned long n_in, n_out;            /* Number of packets in and out */
 317   unsigned long n_kxin, n_kxout;        /* Number of key exchange packets */
 318   unsigned long n_ipin, n_ipout;        /* Number of encrypted packets */
 319 } stats;
 320
 321 /* --- Peer structure --- *
 322  *
 323  * The main structure which glues everything else together.
 324  */
 325
 326 typedef struct peerspec {
 327   char *name;                           /* Peer's name */
 328   const tunnel_ops *tops;               /* Tunnel operations */
 329   unsigned long t_ka;                   /* Keep alive interval */
 330   addr sa;                              /* Socket address to speak to */
 331   size_t sasz;                          /* Socket address size */
 332   unsigned kxf;                         /* Key exchange flags to set */
 333 } peerspec;
 334
 335 typedef struct peer_byname {
 336   sym_base _b;
 337   struct peer *p;
 338 } peer_byname;
 339
 340 typedef struct peer_byaddr {
 341   addrmap_base _b;
 342   struct peer *p;
 343 } peer_byaddr;
 344
 345 typedef struct peer {
 346   peer_byname *byname;                  /* Lookup-by-name block */
 347   peer_byaddr *byaddr;                  /* Lookup-by-address block */
 348   struct ping *pings;                   /* Pings we're waiting for */
 349   peerspec spec;                        /* Specifications for this peer */
 350   tunnel *t;                            /* Tunnel for local packets */
 351   char *ifname;                         /* Interface name for tunnel */
 352   keyset *ks;                           /* List head for keysets */
 353   buf b;                                /* Buffer for sending packets */
 354   stats st;                             /* Statistics */
 355   keyexch kx;                           /* Key exchange protocol block */
 356   sel_timer tka;                        /* Timer for keepalives */
 357 } peer;
 358
 359 typedef struct peer_iter { sym_iter i; } peer_iter;
 360
 361 typedef struct ping {
 362   struct ping *next, *prev;             /* Links to next and previous */
 363   peer *p;                              /* Peer so we can free it */
 364   unsigned msg;                         /* Kind of response expected */
 365   uint32 id;                            /* Id so we can recognize response */
 366   octet magic[32];                      /* Some random data */
 367   sel_timer t;                          /* Timeout for ping */
 368   void (*func)(int /*rc*/, void */*arg*/); /* Function to call when done */
 369   void *arg;                            /* Argument for callback */
 370 } ping;
 371
 372 enum {
 373   PING_NONOTIFY = -1,
 374   PING_OK = 0,
 375   PING_TIMEOUT,
 376   PING_PEERDIED,
 377   PING_MAX
 378 };
 379
 380 /* --- Admin structure --- */
 381
 382 #define OBUFSZ 16384u
 383
 384 typedef struct obuf {
 385   struct obuf *next;                    /* Next buffer in list */
 386   char *p_in, *p_out;                   /* Pointers into the buffer */
 387   char buf[OBUFSZ];                     /* The actual buffer */
 388 } obuf;
 389
 390 typedef struct oqueue {
 391   obuf *hd, *tl;                        /* Head and tail pointers */
 392 } oqueue;
 393
 394 struct admin;
 395
 396 typedef struct admin_bgop {
 397   struct admin_bgop *next, *prev;       /* Links to next and previous */
 398   struct admin *a;                      /* Owner job */
 399   char *tag;                            /* Tag string for messages */
 400   void (*cancel)(struct admin_bgop *);  /* Destructor function */
 401 } admin_bgop;
 402
 403 typedef struct admin_resop {
 404   admin_bgop bg;                        /* Background operation header */
 405   char *addr;                           /* Hostname to be resolved */
 406   bres_client r;                        /* Background resolver task */
 407   sel_timer t;                          /* Timer for resolver */
 408   addr sa;                              /* Socket address */
 409   size_t sasz;                          /* Socket address size */
 410   void (*func)(struct admin_resop *, int); /* Handler */
 411 } admin_resop;
 412
 413 enum { ARES_OK, ARES_FAIL };
 414
 415 typedef struct admin_addop {
 416   admin_resop r;                        /* Name resolution header */
 417   peerspec peer;                        /* Peer pending creation */
 418 } admin_addop;
 419
 420 typedef struct admin_greetop {
 421   admin_resop r;                        /* Name resolution header */
 422   void *c;                              /* Challenge block */
 423   size_t sz;                            /* Length of challenge */
 424 } admin_greetop;
 425
 426 typedef struct admin_pingop {
 427   admin_bgop bg;                        /* Background operation header */
 428   ping ping;                            /* Ping pending response */
 429   struct timeval pingtime;              /* Time last ping was sent */
 430 } admin_pingop;
 431
 432 typedef struct admin_service {
 433   sym_base _b;                          /* Hash table base structure */
 434   char *version;                        /* The provided version */
 435   struct admin *prov;                   /* Which client provides me */
 436   struct admin_service *next, *prev;    /* Client's list of services */
 437 } admin_service;
 438
 439 typedef struct admin_svcop {
 440   admin_bgop bg;                        /* Background operation header */
 441   struct admin *prov;                   /* Client servicing this job */
 442   unsigned index;                       /* This job's index */
 443   struct admin_svcop *next, *prev;      /* Links for provider's jobs */
 444 } admin_svcop;
 445
 446 typedef struct admin_jobentry {
 447   unsigned short seq;                   /* Zero if unused */
 448   union {
 449     admin_svcop *op;                    /* Operation, if slot in use, ... */
 450     uint32 next;                        /* ... or index of next free slot */
 451   } u;
 452 } admin_jobentry;
 453
 454 typedef struct admin_jobtable {
 455   uint32 n, sz;                         /* Used slots and table size */
 456   admin_svcop *active;                  /* List of active jobs */
 457   uint32 free;                          /* Index of first free slot */
 458   admin_jobentry *v;                    /* And the big array of entries */
 459 } admin_jobtable;
 460
 461 typedef struct admin {
 462   struct admin *next, *prev;            /* Links to next and previous */
 463   unsigned f;                           /* Various useful flags */
 464   unsigned ref;                         /* Reference counter */
 465 #ifndef NTRACE
 466   unsigned seq;                         /* Sequence number for tracing */
 467 #endif
 468   oqueue out;                           /* Output buffer list */
 469   oqueue delay;                         /* Delayed output buffer list */
 470   admin_bgop *bg;                       /* Backgrounded operations */
 471   admin_service *svcs;                  /* Which services I provide */
 472   admin_jobtable j;                     /* Table of outstanding jobs */
 473   selbuf b;                             /* Line buffer for commands */
 474   sel_file w;                           /* Selector for write buffering */
 475 } admin;
 476
 477 #define AF_DEAD 1u                      /* Destroy this admin block */
 478 #define AF_CLOSE 2u                     /* Client closed connection */
 479 #define AF_NOTE 4u                      /* Catch notifications */
 480 #define AF_WARN 8u                      /* Catch warning messages */
 481 #ifndef NTRACE
 482   #define AF_TRACE 16u                  /* Catch tracing */
 483 #endif
 484 #define AF_FOREGROUND 32u               /* Quit server when client closes */
 485
 486 #ifndef NTRACE
 487 #  define AF_ALLMSGS (AF_NOTE | AF_TRACE | AF_WARN)
 488 #else
 489 #  define AF_ALLMSGS (AF_NOTE | AF_WARN)
 490 #endif
 491
 492 /*----- Global variables --------------------------------------------------*/
 493
 494 extern sel_state sel;                   /* Global I/O event state */
 495 extern group *gg;                       /* The group we work in */
 496 extern size_t indexsz;                  /* Size of exponent for the group */
 497 extern mp *kpriv;                       /* Our private key */
 498 extern ge *kpub;                        /* Our public key */
 499 extern octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ], buf_u[PKBUFSZ];
 500 extern const tunnel_ops *tunnels[];     /* Table of tunnels (0-term) */
 501 extern const tunnel_ops *tun_default;   /* Default tunnel to use */
 502
 503 #ifndef NTRACE
 504 extern const trace_opt tr_opts[];       /* Trace options array */
 505 extern unsigned tr_flags;               /* Trace options flags */
 506 #endif
 507
 508 /*----- Other macros ------------------------------------------------------*/
 509
 510 #define TIMER noise_timer(RAND_GLOBAL)
 511
 512 /*----- Key management ----------------------------------------------------*/
 513
 514 /* --- @km_reload@ --- *
 515  *
 516  * Arguments:   ---
 517  *
 518  * Returns:     Zero if OK, nonzero to force reloading of keys.
 519  *
 520  * Use:         Checks the keyrings to see if they need reloading.
 521  */
 522
 523 extern int km_reload(void);
 524
 525 /* --- @km_init@ --- *
 526  *
 527  * Arguments:   @const char *kr_priv@ = private keyring file
 528  *              @const char *kr_pub@ = public keyring file
 529  *              @const char *tag@ = tag to load
 530  *
 531  * Returns:     ---
 532  *
 533  * Use:         Initializes, and loads the private key.
 534  */
 535
 536 extern void km_init(const char */*kr_priv*/, const char */*kr_pub*/,
 537                     const char */*tag*/);
 538
 539 /* --- @km_getpubkey@ --- *
 540  *
 541  * Arguments:   @const char *tag@ = public key tag to load
 542  *              @ge *kpub@ = where to put the public key
 543  *              @time_t *t_exp@ = where to put the expiry time
 544  *
 545  * Returns:     Zero if OK, nonzero if it failed.
 546  *
 547  * Use:         Fetches a public key from the keyring.
 548  */
 549
 550 extern int km_getpubkey(const char */*tag*/, ge */*kpub*/,
 551                         time_t */*t_exp*/);
 552
 553 /*----- Key exchange ------------------------------------------------------*/
 554
 555 /* --- @kx_start@ --- *
 556  *
 557  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 558  *              @int forcep@ = nonzero to ignore the quiet timer
 559  *
 560  * Returns:     ---
 561  *
 562  * Use:         Stimulates a key exchange.  If a key exchage is in progress,
 563  *              a new challenge is sent (unless the quiet timer forbids
 564  *              this); if no exchange is in progress, one is commenced.
 565  */
 566
 567 extern void kx_start(keyexch */*kx*/, int /*forcep*/);
 568
 569 /* --- @kx_message@ --- *
 570  *
 571  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 572  *              @unsigned msg@ = the message code
 573  *              @buf *b@ = pointer to buffer containing the packet
 574  *
 575  * Returns:     ---
 576  *
 577  * Use:         Reads a packet containing key exchange messages and handles
 578  *              it.
 579  */
 580
 581 extern void kx_message(keyexch */*kx*/, unsigned /*msg*/, buf */*b*/);
 582
 583 /* --- @kx_free@ --- *
 584  *
 585  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 586  *
 587  * Returns:     ---
 588  *
 589  * Use:         Frees everything in a key exchange context.
 590  */
 591
 592 extern void kx_free(keyexch */*kx*/);
 593
 594 /* --- @kx_newkeys@ --- *
 595  *
 596  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 597  *
 598  * Returns:     ---
 599  *
 600  * Use:         Informs the key exchange module that its keys may have
 601  *              changed.  If fetching the new keys fails, the peer will be
 602  *              destroyed, we log messages and struggle along with the old
 603  *              keys.
 604  */
 605
 606 extern void kx_newkeys(keyexch */*kx*/);
 607
 608 /* --- @kx_init@ --- *
 609  *
 610  * Arguments:   @keyexch *kx@ = pointer to key exchange context
 611  *              @peer *p@ = pointer to peer context
 612  *              @keyset **ks@ = pointer to keyset list
 613  *              @unsigned f@ = various useful flags
 614  *
 615  * Returns:     Zero if OK, nonzero if it failed.
 616  *
 617  * Use:         Initializes a key exchange module.  The module currently
 618  *              contains no keys, and will attempt to initiate a key
 619  *              exchange.
 620  */
 621
 622 extern int kx_init(keyexch */*kx*/, peer */*p*/,
 623                    keyset **/*ks*/, unsigned /*f*/);
 624
 625 /*----- Keysets and symmetric cryptography --------------------------------*/
 626
 627 /* --- @ks_drop@ --- *
 628  *
 629  * Arguments:   @keyset *ks@ = pointer to a keyset
 630  *
 631  * Returns:     ---
 632  *
 633  * Use:         Decrements a keyset's reference counter.  If the counter hits
 634  *              zero, the keyset is freed.
 635  */
 636
 637 extern void ks_drop(keyset */*ks*/);
 638
 639 /* --- @ks_gen@ --- *
 640  *
 641  * Arguments:   @const void *k@ = pointer to key material
 642  *              @size_t x, y, z@ = offsets into key material (see below)
 643  *              @peer *p@ = pointer to peer information
 644  *
 645  * Returns:     A pointer to the new keyset.
 646  *
 647  * Use:         Derives a new keyset from the given key material.  The
 648  *              offsets @x@, @y@ and @z@ separate the key material into three
 649  *              parts.  Between the @k@ and @k + x@ is `my' contribution to
 650  *              the key material; between @k + x@ and @k + y@ is `your'
 651  *              contribution; and between @k + y@ and @k + z@ is a shared
 652  *              value we made together.  These are used to construct two
 653  *              pairs of symmetric keys.  Each pair consists of an encryption
 654  *              key and a message authentication key.  One pair is used for
 655  *              outgoing messages, the other for incoming messages.
 656  *
 657  *              The new key is marked so that it won't be selected for output
 658  *              by @ksl_encrypt@.  You can still encrypt data with it by
 659  *              calling @ks_encrypt@ directly.
 660  */
 661
 662 extern keyset *ks_gen(const void */*k*/,
 663                       size_t /*x*/, size_t /*y*/, size_t /*z*/,
 664                       peer */*p*/);
 665
 666 /* --- @ks_tregen@ --- *
 667  *
 668  * Arguments:   @keyset *ks@ = pointer to a keyset
 669  *
 670  * Returns:     The time at which moves ought to be made to replace this key.
 671  */
 672
 673 extern time_t ks_tregen(keyset */*ks*/);
 674
 675 /* --- @ks_activate@ --- *
 676  *
 677  * Arguments:   @keyset *ks@ = pointer to a keyset
 678  *
 679  * Returns:     ---
 680  *
 681  * Use:         Activates a keyset, so that it can be used for encrypting
 682  *              outgoing messages.
 683  */
 684
 685 extern void ks_activate(keyset */*ks*/);
 686
 687 /* --- @ks_encrypt@ --- *
 688  *
 689  * Arguments:   @keyset *ks@ = pointer to a keyset
 690  *              @unsigned ty@ = message type
 691  *              @buf *b@ = pointer to input buffer
 692  *              @buf *bb@ = pointer to output buffer
 693  *
 694  * Returns:     Zero if successful; @KSERR_REGEN@ if we should negotiate a
 695  *              new key; @KSERR_NOKEYS@ if the key is not usable.  Also
 696  *              returns zero if there was insufficient buffer (but the output
 697  *              buffer is broken in this case).
 698  *
 699  * Use:         Encrypts a block of data using the key.  Note that the `key
 700  *              ought to be replaced' notification is only ever given once
 701  *              for each key.  Also note that this call forces a keyset to be
 702  *              used even if it's marked as not for data output.
 703  */
 704
 705 extern int ks_encrypt(keyset */*ks*/, unsigned /*ty*/,
 706                       buf */*b*/, buf */*bb*/);
 707
 708 /* --- @ks_decrypt@ --- *
 709  *
 710  * Arguments:   @keyset *ks@ = pointer to a keyset
 711  *              @unsigned ty@ = expected type code
 712  *              @buf *b@ = pointer to an input buffer
 713  *              @buf *bb@ = pointer to an output buffer
 714  *
 715  * Returns:     Zero on success; @KSERR_DECRYPT@ on failure.  Also returns
 716  *              zero if there was insufficient buffer (but the output buffer
 717  *              is broken in this case).
 718  *
 719  * Use:         Attempts to decrypt a message using a given key.  Note that
 720  *              requesting decryption with a key directly won't clear a
 721  *              marking that it's not for encryption.
 722  */
 723
 724 extern int ks_decrypt(keyset */*ks*/, unsigned /*ty*/,
 725                       buf */*b*/, buf */*bb*/);
 726
 727 /* --- @ksl_free@ --- *
 728  *
 729  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 730  *
 731  * Returns:     ---
 732  *
 733  * Use:         Frees (releases references to) all of the keys in a keyset.
 734  */
 735
 736 extern void ksl_free(keyset **/*ksroot*/);
 737
 738 /* --- @ksl_link@ --- *
 739  *
 740  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 741  *              @keyset *ks@ = pointer to a keyset
 742  *
 743  * Returns:     ---
 744  *
 745  * Use:         Links a keyset into a list.  A keyset can only be on one list
 746  *              at a time.  Bad things happen otherwise.
 747  */
 748
 749 extern void ksl_link(keyset **/*ksroot*/, keyset */*ks*/);
 750
 751 /* --- @ksl_prune@ --- *
 752  *
 753  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 754  *
 755  * Returns:     ---
 756  *
 757  * Use:         Prunes the keyset list by removing keys which mustn't be used
 758  *              any more.
 759  */
 760
 761 extern void ksl_prune(keyset **/*ksroot*/);
 762
 763 /* --- @ksl_encrypt@ --- *
 764  *
 765  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 766  *              @unsigned ty@ = message type
 767  *              @buf *b@ = pointer to input buffer
 768  *              @buf *bb@ = pointer to output buffer
 769  *
 770  * Returns:     Zero if successful; @KSERR_REGEN@ if it's time to negotiate a
 771  *              new key; @KSERR_NOKEYS@ if there are no suitable keys
 772  *              available.  Also returns zero if there was insufficient
 773  *              buffer space (but the output buffer is broken in this case).
 774  *
 775  * Use:         Encrypts a packet.
 776  */
 777
 778 extern int ksl_encrypt(keyset **/*ksroot*/, unsigned /*ty*/,
 779                        buf */*b*/, buf */*bb*/);
 780
 781 /* --- @ksl_decrypt@ --- *
 782  *
 783  * Arguments:   @keyset **ksroot@ = pointer to keyset list head
 784  *              @unsigned ty@ = expected type code
 785  *              @buf *b@ = pointer to input buffer
 786  *              @buf *bb@ = pointer to output buffer
 787  *
 788  * Returns:     Zero on success; @KSERR_DECRYPT@ on failure.  Also returns
 789  *              zero if there was insufficient buffer (but the output buffer
 790  *              is broken in this case).
 791  *
 792  * Use:         Decrypts a packet.
 793  */
 794
 795 extern int ksl_decrypt(keyset **/*ksroot*/, unsigned /*ty*/,
 796                        buf */*b*/, buf */*bb*/);
 797
 798 /*----- Challenges --------------------------------------------------------*/
 799
 800 /* --- @c_new@ --- *
 801  *
 802  * Arguments:   @buf *b@ = where to put the challenge
 803  *
 804  * Returns:     Zero if OK, nonzero on error.
 805  *
 806  * Use:         Issues a new challenge.
 807  */
 808
 809 extern int c_new(buf */*b*/);
 810
 811 /* --- @c_check@ --- *
 812  *
 813  * Arguments:   @buf *b@ = where to find the challenge
 814  *
 815  * Returns:     Zero if OK, nonzero if it didn't work.
 816  *
 817  * Use:         Checks a challenge.  On failure, the buffer is broken.
 818  */
 819
 820 extern int c_check(buf */*b*/);
 821
 822 /*----- Administration interface ------------------------------------------*/
 823
 824 #define A_END ((char *)0)
 825
 826 /* --- @a_warn@ --- *
 827  *
 828  * Arguments:   @const char *fmt@ = pointer to format string
 829  *              @...@ = other arguments
 830  *
 831  * Returns:     ---
 832  *
 833  * Use:         Informs all admin connections of a warning.
 834  */
 835
 836 extern void a_warn(const char */*fmt*/, ...);
 837
 838 /* --- @a_notify@ --- *
 839  *
 840  * Arguments:   @const char *fmt@ = pointer to format string
 841  *              @...@ = other arguments
 842  *
 843  * Returns:     ---
 844  *
 845  * Use:         Sends a notification to interested admin connections.
 846  */
 847
 848 extern void a_notify(const char */*fmt*/, ...);
 849
 850 /* --- @a_create@ --- *
 851  *
 852  * Arguments:   @int fd_in, fd_out@ = file descriptors to use
 853  *              @unsigned f@ = initial flags to set
 854  *
 855  * Returns:     ---
 856  *
 857  * Use:         Creates a new admin connection.
 858  */
 859
 860 extern void a_create(int /*fd_in*/, int /*fd_out*/, unsigned /*f*/);
 861
 862 /* --- @a_quit@ --- *
 863  *
 864  * Arguments:   ---
 865  *
 866  * Returns:     ---
 867  *
 868  * Use:         Shuts things down nicely.
 869  */
 870
 871 extern void a_quit(void);
 872
 873 /* --- @a_preselect@ --- *
 874  *
 875  * Arguments:   ---
 876  *
 877  * Returns:     ---
 878  *
 879  * Use:         Informs the admin module that we're about to select again,
 880  *              and that it should do cleanup things it has delayed until a
 881  *              `safe' time.
 882  */
 883
 884 extern void a_preselect(void);
 885
 886 /* --- @a_daemon@ --- *
 887  *
 888  * Arguments:   ---
 889  *
 890  * Returns:     ---
 891  *
 892  * Use:         Informs the admin module that it's a daemon.
 893  */
 894
 895 extern void a_daemon(void);
 896
 897 /* --- @a_init@ --- *
 898  *
 899  * Arguments:   @const char *sock@ = socket name to create
 900  *
 901  * Returns:     ---
 902  *
 903  * Use:         Creates the admin listening socket.
 904  */
 905
 906 extern void a_init(const char */*sock*/);
 907
 908 /*----- Mapping with addresses as keys ------------------------------------*/
 909
 910 /* --- @am_create@ --- *
 911  *
 912  * Arguments:   @addrmap *m@ = pointer to map
 913  *
 914  * Returns:     ---
 915  *
 916  * Use:         Create an address map, properly set up.
 917  */
 918
 919 extern void am_create(addrmap */*m*/);
 920
 921 /* --- @am_destroy@ --- *
 922  *
 923  * Arguments:   @addrmap *m@ = pointer to map
 924  *
 925  * Returns:     ---
 926  *
 927  * Use:         Destroy an address map, throwing away all the entries.
 928  */
 929
 930 extern void am_destroy(addrmap */*m*/);
 931
 932 /* --- @am_find@ --- *
 933  *
 934  * Arguments:   @addrmap *m@ = pointer to map
 935  *              @const addr *a@ = address to look up
 936  *              @size_t sz@ = size of block to allocate
 937  *              @unsigned *f@ = where to store flags
 938  *
 939  * Returns:     Pointer to found item, or null.
 940  *
 941  * Use:         Finds a record with the given IP address, set @*f@ nonzero
 942  *              and returns it.  If @sz@ is zero, and no match was found,
 943  *              return null; otherwise allocate a new block of @sz@ bytes,
 944  *              clear @*f@ to zero and return the block pointer.
 945  */
 946
 947 extern void *am_find(addrmap */*m*/, const addr */*a*/,
 948                      size_t /*sz*/, unsigned */*f*/);
 949
 950 /* --- @am_remove@ --- *
 951  *
 952  * Arguments:   @addrmap *m@ = pointer to map
 953  *              @void *i@ = pointer to the item
 954  *
 955  * Returns:     ---
 956  *
 957  * Use:         Removes an item from the map.
 958  */
 959
 960 extern void am_remove(addrmap */*m*/, void */*i*/);
 961
 962 /*----- Peer management ---------------------------------------------------*/
 963
 964 /* --- @p_txstart@ --- *
 965  *
 966  * Arguments:   @peer *p@ = pointer to peer block
 967  *              @unsigned msg@ = message type code
 968  *
 969  * Returns:     A pointer to a buffer to write to.
 970  *
 971  * Use:         Starts sending to a peer.  Only one send can happen at a
 972  *              time.
 973  */
 974
 975 extern buf *p_txstart(peer */*p*/, unsigned /*msg*/);
 976
 977 /* --- @p_txend@ --- *
 978  *
 979  * Arguments:   @peer *p@ = pointer to peer block
 980  *
 981  * Returns:     ---
 982  *
 983  * Use:         Sends a packet to the peer.
 984  */
 985
 986 extern void p_txend(peer */*p*/);
 987
 988 /* --- @p_pingsend@ --- *
 989  *
 990  * Arguments:   @peer *p@ = destination peer
 991  *              @ping *pg@ = structure to fill in
 992  *              @unsigned type@ = message type
 993  *              @unsigned long timeout@ = how long to wait before giving up
 994  *              @void (*func)(int, void *)@ = callback function
 995  *              @void *arg@ = argument for callback
 996  *
 997  * Returns:     Zero if successful, nonzero if it failed.
 998  *
 999  * Use:         Sends a ping to a peer.  Call @func@ with a nonzero argument
1000  *              if we get an answer within the timeout, or zero if no answer.
1001  */
1002
1003 extern int p_pingsend(peer */*p*/, ping */*pg*/, unsigned /*type*/,
1004                       unsigned long /*timeout*/,
1005                       void (*/*func*/)(int, void *), void */*arg*/);
1006
1007 /* --- @p_pingdone@ --- *
1008  *
1009  * Arguments:   @ping *p@ = ping structure
1010  *              @int rc@ = return code to pass on
1011  *
1012  * Returns:     ---
1013  *
1014  * Use:         Disposes of a ping structure, maybe sending a notification.
1015  */
1016
1017 extern void p_pingdone(ping */*p*/, int /*rc*/);
1018
1019 /* --- @p_greet@ --- *
1020  *
1021  * Arguments:   @peer *p@ = peer to send to
1022  *              @const void *c@ = pointer to challenge
1023  *              @size_t sz@ = size of challenge
1024  *
1025  * Returns:     ---
1026  *
1027  * Use:         Sends a greeting packet.
1028  */
1029
1030 extern void p_greet(peer */*p*/, const void */*c*/, size_t /*sz*/);
1031
1032 /* --- @p_tun@ --- *
1033  *
1034  * Arguments:   @peer *p@ = pointer to peer block
1035  *              @buf *b@ = buffer containing incoming packet
1036  *
1037  * Returns:     ---
1038  *
1039  * Use:         Handles a packet which needs to be sent to a peer.
1040  */
1041
1042 extern void p_tun(peer */*p*/, buf */*b*/);
1043
1044 /* --- @p_keyreload@ --- *
1045  *
1046  * Arguments:   ---
1047  *
1048  * Returns:     ---
1049  *
1050  * Use:         Forces a check of the daemon's keyring files.
1051  */
1052
1053 extern void p_keyreload(void);
1054
1055 /* --- @p_interval@ --- *
1056  *
1057  * Arguments:   ---
1058  *
1059  * Returns:     ---
1060  *
1061  * Use:         Called periodically to do tidying.
1062  */
1063
1064 extern void p_interval(void);
1065
1066 /* --- @p_stats@ --- *
1067  *
1068  * Arguments:   @peer *p@ = pointer to a peer block
1069  *
1070  * Returns:     A pointer to the peer's statistics.
1071  */
1072
1073 extern stats *p_stats(peer */*p*/);
1074
1075 /* --- @p_ifname@ --- *
1076  *
1077  * Arguments:   @peer *p@ = pointer to a peer block
1078  *
1079  * Returns:     A pointer to the peer's interface name.
1080  */
1081
1082 extern const char *p_ifname(peer */*p*/);
1083
1084 /* --- @p_setifname@ --- *
1085  *
1086  * Arguments:   @peer *p@ = pointer to a peer block
1087  *              @const char *name@ = pointer to the new name
1088  *
1089  * Returns:     ---
1090  *
1091  * Use:         Changes the name held for a peer's interface.
1092  */
1093
1094 extern void p_setifname(peer */*p*/, const char */*name*/);
1095
1096 /* --- @p_addr@ --- *
1097  *
1098  * Arguments:   @peer *p@ = pointer to a peer block
1099  *
1100  * Returns:     A pointer to the peer's address.
1101  */
1102
1103 extern const addr *p_addr(peer */*p*/);
1104
1105 /* --- @p_init@ --- *
1106  *
1107  * Arguments:   @struct in_addr addr@ = address to bind to
1108  *              @unsigned port@ = port number to listen to
1109  *
1110  * Returns:     ---
1111  *
1112  * Use:         Initializes the peer system; creates the socket.
1113  */
1114
1115 extern void p_init(struct in_addr /*addr*/, unsigned /*port*/);
1116
1117 /* --- @p_port@ --- *
1118  *
1119  * Arguments:   ---
1120  *
1121  * Returns:     Port number used for socket.
1122  */
1123
1124 unsigned p_port(void);
1125
1126 /* --- @p_create@ --- *
1127  *
1128  * Arguments:   @peerspec *spec@ = information about this peer
1129  *
1130  * Returns:     Pointer to the peer block, or null if it failed.
1131  *
1132  * Use:         Creates a new named peer block.  No peer is actually attached
1133  *              by this point.
1134  */
1135
1136 extern peer *p_create(peerspec */*spec*/);
1137
1138 /* --- @p_name@ --- *
1139  *
1140  * Arguments:   @peer *p@ = pointer to a peer block
1141  *
1142  * Returns:     A pointer to the peer's name.
1143  *
1144  * Use:         Equivalent to @p_spec(p)->name@.
1145  */
1146
1147 extern const char *p_name(peer */*p*/);
1148
1149 /* --- @p_spec@ --- *
1150  *
1151  * Arguments:   @peer *p@ = pointer to a peer block
1152  *
1153  * Returns:     Pointer to the peer's specification
1154  */
1155
1156 extern const peerspec *p_spec(peer */*p*/);
1157
1158 /* --- @p_findbyaddr@ --- *
1159  *
1160  * Arguments:   @const addr *a@ = address to look up
1161  *
1162  * Returns:     Pointer to the peer block, or null if not found.
1163  *
1164  * Use:         Finds a peer by address.
1165  */
1166
1167 extern peer *p_findbyaddr(const addr */*a*/);
1168
1169 /* --- @p_find@ --- *
1170  *
1171  * Arguments:   @const char *name@ = name to look up
1172  *
1173  * Returns:     Pointer to the peer block, or null if not found.
1174  *
1175  * Use:         Finds a peer by name.
1176  */
1177
1178 extern peer *p_find(const char */*name*/);
1179
1180 /* --- @p_destroy@ --- *
1181  *
1182  * Arguments:   @peer *p@ = pointer to a peer
1183  *
1184  * Returns:     ---
1185  *
1186  * Use:         Destroys a peer.
1187  */
1188
1189 extern void p_destroy(peer */*p*/);
1190
1191 /* --- @FOREACH_PEER@ --- *
1192  *
1193  * Arguments:   @p@ = name to bind to each peer
1194  *              @stuff@ = thing to do for each item
1195  *
1196  * Use:         Does something for each current peer.
1197  */
1198
1199 #define FOREACH_PEER(p, stuff) do {                                     \
1200   peer_iter i_;                                                         \
1201   peer *p;                                                              \
1202   for (p_mkiter(&i_); (p = p_next(&i_)) != 0; ) do stuff while (0);     \
1203 } while (0)
1204
1205 /* --- @p_mkiter@ --- *
1206  *
1207  * Arguments:   @peer_iter *i@ = pointer to an iterator
1208  *
1209  * Returns:     ---
1210  *
1211  * Use:         Initializes the iterator.
1212  */
1213
1214 extern void p_mkiter(peer_iter */*i*/);
1215
1216 /* --- @p_next@ --- *
1217  *
1218  * Arguments:   @peer_iter *i@ = pointer to an iterator
1219  *
1220  * Returns:     Next peer, or null if at the end.
1221  *
1222  * Use:         Returns the next peer.
1223  */
1224
1225 extern peer *p_next(peer_iter */*i*/);
1226
1227 /*----- Tunnel drivers ----------------------------------------------------*/
1228
1229 #ifdef TUN_LINUX
1230   extern const tunnel_ops tun_linux;
1231 #endif
1232
1233 #ifdef TUN_UNET
1234   extern const tunnel_ops tun_unet;
1235 #endif
1236
1237 #ifdef TUN_BSD
1238   extern const tunnel_ops tun_bsd;
1239 #endif
1240
1241 extern const tunnel_ops tun_slip;
1242
1243 /*----- Other handy utilities ---------------------------------------------*/
1244
1245 /* --- @mpstr@ --- *
1246  *
1247  * Arguments:   @mp *m@ = a multiprecision integer
1248  *
1249  * Returns:     A pointer to the integer's textual representation.
1250  *
1251  * Use:         Converts a multiprecision integer to a string.  Corrupts
1252  *              @buf_u@.
1253  */
1254
1255 extern const char *mpstr(mp */*m*/);
1256
1257 /* --- @gestr@ --- *
1258  *
1259  * Arguments:   @group *g@ = a group
1260  *              @ge *x@ = a group element
1261  *
1262  * Returns:     A pointer to the element's textual representation.
1263  *
1264  * Use:         Converts a group element to a string.  Corrupts
1265  *              @buf_u@.
1266  */
1267
1268 extern const char *gestr(group */*g*/, ge */*x*/);
1269
1270 /* --- @timestr@ --- *
1271  *
1272  * Arguments:   @time_t t@ = a time to convert
1273  *
1274  * Returns:     A pointer to a textual representation of the time.
1275  *
1276  * Use:         Converts a time to a textual representation.  Corrupts
1277  *              @buf_u@.
1278  */
1279
1280 extern const char *timestr(time_t /*t*/);
1281
1282 /* --- @mystrieq@ --- *
1283  *
1284  * Arguments:   @const char *x, *y@ = two strings
1285  *
1286  * Returns:     True if @x@ and @y are equal, up to case.
1287  */
1288
1289 extern int mystrieq(const char */*x*/, const char */*y*/);
1290
1291 /* --- @seq_reset@ --- *
1292  *
1293  * Arguments:   @seqwin *s@ = sequence-checking window
1294  *
1295  * Returns:     ---
1296  *
1297  * Use:         Resets a sequence number window.
1298  */
1299
1300 extern void seq_reset(seqwin */*s*/);
1301
1302 /* --- @seq_check@ --- *
1303  *
1304  * Arguments:   @seqwin *s@ = sequence-checking window
1305  *              @uint32 q@ = sequence number to check
1306  *              @const char *service@ = service to report message from
1307  *
1308  * Returns:     A @SEQ_@ code.
1309  *
1310  * Use:         Checks a sequence number against the window, updating things
1311  *              as necessary.
1312  */
1313
1314 extern int seq_check(seqwin */*s*/, uint32 /*q*/, const char */*service*/);
1315
1316 /*----- That's all, folks -------------------------------------------------*/
1317
1318 #ifdef __cplusplus
1319   }
1320 #endif
1321
1322 #endif