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

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