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