3 * $Id: tripe.h,v 1.11 2002/01/13 14:57:42 mdw Exp $
5 * Main header file for TrIPE
7 * (c) 2001 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Trivial IP Encryption (TrIPE).
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.
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.
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.
29 /*----- Revision history --------------------------------------------------*
32 * Revision 1.11 2002/01/13 14:57:42 mdw
35 * Revision 1.10 2002/01/13 14:54:58 mdw
38 * Revision 1.9 2001/06/22 19:40:36 mdw
39 * Support expiry of other peers' public keys.
41 * Revision 1.8 2001/06/19 22:10:57 mdw
42 * Some more constants for the algorithms. Document the packet format
43 * change for non-malleability. Moved @buf@ definitions to separate header
46 * Revision 1.7 2001/03/03 12:07:08 mdw
47 * Rename word get and put functions now that there's 16-bit support.
49 * Revision 1.6 2001/02/19 19:11:09 mdw
50 * Output buffering on admin connections.
52 * Revision 1.5 2001/02/16 21:41:43 mdw
53 * Major changes. See source files for details.
55 * Revision 1.4 2001/02/05 19:56:37 mdw
56 * Sequence number protection, and BSD tunnels.
58 * Revision 1.3 2001/02/04 01:17:55 mdw
59 * Create a configuration header file to tidy up command lines.
61 * Revision 1.2 2001/02/03 22:40:29 mdw
62 * Put timer information into the entropy pool when packets are received
63 * and on similar events. Reseed the generator on the interval timer.
65 * Revision 1.1 2001/02/03 20:26:37 mdw
77 /*----- Header files ------------------------------------------------------*/
92 #include <sys/types.h>
98 #include <sys/socket.h>
100 #include <netinet/in.h>
101 #include <arpa/inet.h>
107 #include <mLib/alloc.h>
108 #include <mLib/arena.h>
109 #include <mLib/bres.h>
110 #include <mLib/dstr.h>
111 #include <mLib/env.h>
112 #include <mLib/fdflags.h>
113 #include <mLib/fwatch.h>
114 #include <mLib/mdwopt.h>
115 #include <mLib/quis.h>
116 #include <mLib/report.h>
117 #include <mLib/sel.h>
118 #include <mLib/selbuf.h>
119 #include <mLib/sig.h>
120 #include <mLib/str.h>
121 #include <mLib/sub.h>
122 #include <mLib/trace.h>
124 #include <catacomb/gcipher.h>
125 #include <catacomb/gmac.h>
126 #include <catacomb/grand.h>
127 #include <catacomb/key.h>
128 #include <catacomb/paranoia.h>
130 #include <catacomb/noise.h>
131 #include <catacomb/rand.h>
133 #include <catacomb/mp.h>
134 #include <catacomb/mpmont.h>
135 #include <catacomb/mprand.h>
136 #include <catacomb/dh.h>
143 /*----- Magic numbers -----------------------------------------------------*/
145 /* --- Tunnel types --- */
151 /* --- Trace flags --- */
159 #define T_KEYEXCH 64u
160 #define T_KEYMGMT 128u
166 #define SEC(n) (n##u)
167 #define MIN(n) (n##u * 60u)
168 #define MEG(n) (n##ul * 1024ul * 1024ul)
170 /* --- Other things --- */
172 #define PKBUFSZ 65536
174 /*----- TrIPE protocol ----------------------------------------------------*/
176 /* --- TrIPE message format --- *
178 * A packet begins with a single-byte message type. The top four bits are a
179 * category code used to send the message to the right general place in the
180 * code; the bottom bits identify the actual message type.
183 #define MSG_CATMASK 0xf0
184 #define MSG_TYPEMASK 0x0f
186 /* --- Encrypted message packets --- *
188 * Messages of category @MSG_PACKET@ contain encrypted network packets. The
189 * message content is a symmetric-encrypted block (see below). Reception of
190 * a packet encrypted under a new key implicitly permits that key to be used
191 * to send further packets.
193 * The only packet type accepted is zero.
195 * Packets may be encrypted under any live keyset, but should use the most
199 #define MSG_PACKET 0x00
201 /* --- Key exchange packets --- */
203 #define MSG_KEYEXCH 0x10
205 #define KX_PRECHAL 0u
210 #define KX_SWITCHOK 5u
213 /* --- Symmetric encryption and keysets --- *
215 * Packets consist of an 80-bit MAC, a 32-bit sequence number, and the
218 * The plaintext is encrypted using Blowfish in CBC mode with ciphertext
219 * stealing (as described in [Schneier]. The initialization vector is
220 * selected randomly, and prepended to the actual ciphertext.
222 * The MAC is computed using the HMAC construction with RIPEMD160 over the
223 * sequence number and the ciphertext (with IV); the first 80 bits of the
224 * output are used. (This is the minimum allowed by the draft FIPS for HMAC,
225 * and the recommended truncation.)
227 * A keyset consists of
229 * * an integrity (MAC) key;
230 * * a confidentiality (encryption) key; and
231 * * a sequence numbering space
233 * in each direction. The packets sent by a host encrypted under a
234 * particular keyset are assigned consecutive sequence numbers starting from
235 * zero. The receiving host must ensure that it only accepts each packet at
236 * most once. It should maintain a window of sequence numbers: packets with
237 * numbers beyond the end of the window are accepted and cause the window to
238 * be advanced; packets with numbers before the start of the window are
239 * rejected; packets with numbers which appear within the window are accepted
240 * only if the number has not been seen before.
242 * When a host sends a @KX_SWITCH@ or @KX_SWITCHOK@ message, it installs the
243 * newly-negotiated keyset in a `listen-only' state: it may not send a packet
244 * encrypted under the keyset until either it has received a @KX_SWITCH@ or
245 * @KX_SWITCHOK@ message, or a @MSG_PACKET@ encrypted under the keyset, from
249 /*----- Cipher selections -------------------------------------------------*/
251 #include <catacomb/blowfish.h>
252 #include <catacomb/blowfish-cbc.h>
253 #include <catacomb/blowfish-counter.h>
254 #include <catacomb/rmd160.h>
255 #include <catacomb/rmd160-hmac.h>
257 #define CIPHER (&blowfish_cbc)
258 #define MAC (&rmd160_hmac)
260 #define HASH_CTX rmd160_ctx
261 #define HASH_INIT rmd160_init
262 #define HASH rmd160_hash
263 #define HASH_STRING(c, s) HASH((c), s, sizeof(s))
264 #define HASH_DONE rmd160_done
265 #define HASHSZ RMD160_HASHSZ
267 #define MGF_CTX blowfish_counterctx
268 #define MGF_INIT blowfish_counterinit
269 #define MGF_CRYPT blowfish_counterencrypt
272 #define IVSZ BLOWFISH_BLKSZ
275 /*----- Data structures ---------------------------------------------------*/
277 /* --- Socket addresses --- *
279 * A magic union of supported socket addresses.
284 struct sockaddr_in sin;
287 /* --- A symmetric keyset --- *
289 * A keyset contains a set of symmetric keys for encrypting and decrypting
290 * packets. Keysets are stored in a list, sorted in reverse order of
291 * creation, so that the most recent keyset (the one most likely to be used)
294 * Each keyset has a time limit and a data limit. The keyset is destroyed
295 * when either it has existed for too long, or it has been used to encrypt
296 * too much data. New key exchanges are triggered when keys are close to
300 typedef struct keyset {
301 struct keyset *next; /* Next active keyset in the list */
302 unsigned ref; /* Reference count for keyset */
303 time_t t_exp; /* Expiry time for this keyset */
304 unsigned long sz_exp; /* Data limit for the keyset */
305 T( unsigned seq; ) /* Sequence number for tracing */
306 unsigned f; /* Various useful flags */
307 gcipher *cin, *cout; /* Keyset ciphers for encryption */
308 gmac *min, *mout; /* Keyset MACs for integrity */
309 uint32 oseq; /* Outbound sequence number */
310 uint32 iseq, iwin; /* Inbound sequence number */
313 #define KS_SEQWINSZ 32 /* Bits in sequence number window */
315 #define KSF_LISTEN 1u /* Don't encrypt packets yet */
316 #define KSF_LINK 2u /* Key is in a linked list */
318 /* --- Key exchange --- *
320 * TrIPE uses the Wrestlers Protocol for its key exchange. The Wrestlers
321 * Protocol has a number of desirable features (e.g., perfect forward
322 * secrecy, and zero-knowledge authentication) which make it attractive for
323 * use in TrIPE. The Wrestlers Protocol was designed by Mark Wooding and
330 typedef struct kxchal {
331 struct keyexch *kx; /* Pointer back to key exchange */
332 mp *c; /* Responder's challenge */
333 mp *r; /* My reply to the challenge */
334 keyset *ks; /* Pointer to temporary keyset */
335 unsigned f; /* Various useful flags */
336 sel_timer t; /* Response timer for challenge */
337 octet hc[HASHSZ]; /* Hash of his challenge */
338 mp *ck; /* The check value */
339 octet hswrq_in[HASHSZ]; /* Inbound switch request message */
340 octet hswok_in[HASHSZ]; /* Inbound switch confirmation */
341 octet hswrq_out[HASHSZ]; /* Outbound switch request message */
342 octet hswok_out[HASHSZ]; /* Outbound switch confirmation */
345 typedef struct keyexch {
346 struct peer *p; /* Pointer back to the peer */
347 keyset **ks; /* Peer's list of keysets */
348 unsigned f; /* Various useful flags */
349 unsigned s; /* Current state in exchange */
350 sel_timer t; /* Timer for next exchange */
351 dh_pub kpub; /* Peer's public key */
352 time_t texp_kpub; /* Expiry time for public key */
353 mp *alpha; /* My temporary secret */
354 mp *c; /* My challenge */
355 mp *rx; /* The expected response */
356 unsigned nr; /* Number of extant responses */
357 time_t t_valid; /* When this exchange goes bad */
358 octet hc[HASHSZ]; /* Hash of my challenge */
359 kxchal *r[KX_NCHAL]; /* Array of challenges */
362 #define KXF_TIMER 1u /* Waiting for a timer to go off */
363 #define KXF_DEAD 2u /* The key-exchanger isn't up */
364 #define KXF_PUBKEY 4u /* Key exchanger has a public key */
367 KXS_DEAD, /* Uninitialized state (magical) */
368 KXS_CHAL, /* Main answer-challenges state */
369 KXS_COMMIT, /* Committed: send switch request */
370 KXS_SWITCH /* Switched: send confirmation */
373 /* --- Tunnel structure --- *
375 * Used to maintain system-specific information about the tunnel interface.
378 typedef struct tunnel {
379 #if TUN_TYPE == TUN_UNET
380 sel_file f; /* Selector for Usernet device */
381 struct peer *p; /* Pointer to my peer */
382 #elif TUN_TYPE == TUN_BSD
383 sel_file f; /* Selector for tunnel device */
384 struct peer *p; /* Pointer to my peer */
385 unsigned n; /* Number of my tunnel device */
387 # error "No support for this tunnel type"
391 /* --- Peer statistics --- *
393 * Contains various interesting and not-so-interesting statistics about a
394 * peer. This is updated by various parts of the code. The format of the
395 * structure isn't considered private, and @p_stats@ returns a pointer to the
396 * statistics block for a given peer.
399 typedef struct stats {
400 unsigned long sz_in, sz_out; /* Size of all data in and out */
401 unsigned long sz_kxin, sz_kxout; /* Size of key exchange messages */
402 unsigned long sz_ipin, sz_ipout; /* Size of encapsulated IP packets */
403 time_t t_start, t_last; /* Time peer created, last recv */
404 unsigned long n_reject; /* Number of rejected packets */
405 unsigned long n_in, n_out; /* Number of packets in and out */
406 unsigned long n_kxin, n_kxout; /* Number of key exchange packets */
407 unsigned long n_ipin, n_ipout; /* Number of encrypted packets */
410 /* --- Peer structure --- *
412 * The main structure which glues everything else together.
415 typedef struct peer {
416 struct peer *next, *prev; /* Links to next and previous */
417 char *name; /* Name of this peer */
418 tunnel t; /* Tunnel for local packets */
419 keyset *ks; /* List head for keysets */
420 buf b; /* Buffer for sending packets */
421 addr peer; /* Peer socket address */
422 size_t sasz; /* Socket address size */
423 stats st; /* Statistics */
424 keyexch kx; /* Key exchange protocol block */
427 /* --- Admin structure --- */
429 #define OBUFSZ 16384u
431 typedef struct obuf {
432 struct obuf *next; /* Next buffer in list */
433 char *p_in, *p_out; /* Pointers into the buffer */
434 char buf[OBUFSZ]; /* The actual buffer */
437 typedef struct admin {
438 struct admin *next, *prev; /* Links to next and previous */
439 unsigned f; /* Various useful flags */
441 unsigned seq; /* Sequence number for tracing */
443 char *pname; /* Peer name to create */
444 char *paddr; /* Address string to resolve */
445 obuf *o_head, *o_tail; /* Output buffer list */
446 selbuf b; /* Line buffer for commands */
447 sel_file w; /* Selector for write buffering */
448 bres_client r; /* Background resolver task */
449 sel_timer t; /* Timer for resolver */
450 addr peer; /* Address to set */
451 size_t sasz; /* Size of the address */
454 #define AF_DEAD 1u /* Destroy this admin block */
455 #define AF_LOCK 2u /* Don't destroy it yet */
457 /*----- Global variables --------------------------------------------------*/
459 extern sel_state sel; /* Global I/O event state */
460 extern dh_priv kpriv; /* Our private key */
461 extern mpmont mg; /* Montgomery context for DH group */
462 extern octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ];
465 extern const trace_opt tr_opts[]; /* Trace options array */
466 extern unsigned tr_flags; /* Trace options flags */
469 /*----- Other macros ------------------------------------------------------*/
471 #define TIMER noise_timer(RAND_GLOBAL)
473 /*----- Key management ----------------------------------------------------*/
475 /* --- @km_interval@ --- *
479 * Returns: Zero if OK, nonzero to force reloading of keys.
481 * Use: Called on the interval timer to perform various useful jobs.
484 extern int km_interval(void);
486 /* --- @km_init@ --- *
488 * Arguments: @const char *kr_priv@ = private keyring file
489 * @const char *kr_pub@ = public keyring file
490 * @const char *tag@ = tag to load
494 * Use: Initializes, and loads the private key.
497 extern void km_init(const char */*kr_priv*/, const char */*kr_pub*/,
498 const char */*tag*/);
500 /* --- @km_getpubkey@ --- *
502 * Arguments: @const char *tag@ = public key tag to load
503 * @dh_pub *kpub@ = where to put the public key
504 * @time_t *t_exp@ = where to put the expiry time
506 * Returns: Zero if OK, nonzero if it failed.
508 * Use: Fetches a public key from the keyring.
511 extern int km_getpubkey(const char */*tag*/, dh_pub */*kpub*/,
514 /*----- Key exchange ------------------------------------------------------*/
516 /* --- @kx_start@ --- *
518 * Arguments: @keyexch *kx@ = pointer to key exchange context
522 * Use: Stimulates a key exchange. If a key exchage is in progress,
523 * a new challenge is sent (unless the quiet timer forbids
524 * this); if no exchange is in progress, one is commenced.
527 extern void kx_start(keyexch */*kx*/);
529 /* --- @kx_message@ --- *
531 * Arguments: @keyexch *kx@ = pointer to key exchange context
532 * @unsigned msg@ = the message code
533 * @buf *b@ = pointer to buffer containing the packet
537 * Use: Reads a packet containing key exchange messages and handles
541 extern void kx_message(keyexch */*kx*/, unsigned /*msg*/, buf */*b*/);
543 /* --- @kx_free@ --- *
545 * Arguments: @keyexch *kx@ = pointer to key exchange context
549 * Use: Frees everything in a key exchange context.
552 extern void kx_free(keyexch */*kx*/);
554 /* --- @kx_newkeys@ --- *
556 * Arguments: @keyexch *kx@ = pointer to key exchange context
560 * Use: Informs the key exchange module that its keys may have
561 * changed. If fetching the new keys fails, the peer will be
562 * destroyed, we log messages and struggle along with the old
566 extern void kx_newkeys(keyexch */*kx*/);
568 /* --- @kx_init@ --- *
570 * Arguments: @keyexch *kx@ = pointer to key exchange context
571 * @peer *p@ = pointer to peer context
572 * @keyset **ks@ = pointer to keyset list
574 * Returns: Zero if OK, nonzero if it failed.
576 * Use: Initializes a key exchange module. The module currently
577 * contains no keys, and will attempt to initiate a key
581 extern int kx_init(keyexch */*kx*/, peer */*p*/, keyset **/*ks*/);
583 /*----- Keysets and symmetric cryptography --------------------------------*/
585 /* --- @ks_drop@ --- *
587 * Arguments: @keyset *ks@ = pointer to a keyset
591 * Use: Decrements a keyset's reference counter. If the counter hits
592 * zero, the keyset is freed.
595 extern void ks_drop(keyset */*ks*/);
597 /* --- @ks_gen@ --- *
599 * Arguments: @const void *k@ = pointer to key material
600 * @size_t x, y, z@ = offsets into key material (see below)
602 * Returns: A pointer to the new keyset.
604 * Use: Derives a new keyset from the given key material. The
605 * offsets @x@, @y@ and @z@ separate the key material into three
606 * parts. Between the @k@ and @k + x@ is `my' contribution to
607 * the key material; between @k + x@ and @k + y@ is `your'
608 * contribution; and between @k + y@ and @k + z@ is a shared
609 * value we made together. These are used to construct two
610 * pairs of symmetric keys. Each pair consists of an encryption
611 * key and a message authentication key. One pair is used for
612 * outgoing messages, the other for incoming messages.
614 * The new key is marked so that it won't be selected for output
615 * by @ksl_encrypt@. You can still encrypt data with it by
616 * calling @ks_encrypt@ directly.
619 extern keyset *ks_gen(const void */*k*/,
620 size_t /*x*/, size_t /*y*/, size_t /*z*/);
622 /* --- @ks_tregen@ --- *
624 * Arguments: @keyset *ks@ = pointer to a keyset
626 * Returns: The time at which moves ought to be made to replace this key.
629 extern time_t ks_tregen(keyset */*ks*/);
631 /* --- @ks_activate@ --- *
633 * Arguments: @keyset *ks@ = pointer to a keyset
637 * Use: Activates a keyset, so that it can be used for encrypting
641 extern void ks_activate(keyset */*ks*/);
643 /* --- @ks_encrypt@ --- *
645 * Arguments: @keyset *ks@ = pointer to a keyset
646 * @buf *b@ = pointer to input buffer
647 * @buf *bb@ = pointer to output buffer
649 * Returns: Zero if OK, nonzero if the key needs replacing. If the
650 * encryption failed, the output buffer is broken and zero is
653 * Use: Encrypts a block of data using the key. Note that the `key
654 * ought to be replaced' notification is only ever given once
655 * for each key. Also note that this call forces a keyset to be
656 * used even if it's marked as not for data output.
659 extern int ks_encrypt(keyset */*ks*/, buf */*b*/, buf */*bb*/);
661 /* --- @ks_decrypt@ --- *
663 * Arguments: @keyset *ks@ = pointer to a keyset
664 * @buf *b@ = pointer to an input buffer
665 * @buf *bb@ = pointer to an output buffer
667 * Returns: Zero on success, or nonzero if there was some problem.
669 * Use: Attempts to decrypt a message using a given key. Note that
670 * requesting decryption with a key directly won't clear a
671 * marking that it's not for encryption.
674 extern int ks_decrypt(keyset */*ks*/, buf */*b*/, buf */*bb*/);
676 /* --- @ksl_free@ --- *
678 * Arguments: @keyset **ksroot@ = pointer to keyset list head
682 * Use: Frees (releases references to) all of the keys in a keyset.
685 extern void ksl_free(keyset **/*ksroot*/);
687 /* --- @ksl_link@ --- *
689 * Arguments: @keyset **ksroot@ = pointer to keyset list head
690 * @keyset *ks@ = pointer to a keyset
694 * Use: Links a keyset into a list. A keyset can only be on one list
695 * at a time. Bad things happen otherwise.
698 extern void ksl_link(keyset **/*ksroot*/, keyset */*ks*/);
700 /* --- @ksl_prune@ --- *
702 * Arguments: @keyset **ksroot@ = pointer to keyset list head
706 * Use: Prunes the keyset list by removing keys which mustn't be used
710 extern void ksl_prune(keyset **/*ksroot*/);
712 /* --- @ksl_encrypt@ --- *
714 * Arguments: @keyset **ksroot@ = pointer to keyset list head
715 * @buf *b@ = pointer to input buffer
716 * @buf *bb@ = pointer to output buffer
718 * Returns: Nonzero if a new key is needed.
720 * Use: Encrypts a packet.
723 extern int ksl_encrypt(keyset **/*ksroot*/, buf */*b*/, buf */*bb*/);
725 /* --- @ksl_decrypt@ --- *
727 * Arguments: @keyset **ksroot@ = pointer to keyset list head
728 * @buf *b@ = pointer to input buffer
729 * @buf *bb@ = pointer to output buffer
731 * Returns: Nonzero if the packet couldn't be decrypted.
733 * Use: Decrypts a packet.
736 extern int ksl_decrypt(keyset **/*ksroot*/, buf */*b*/, buf */*bb*/);
738 /*----- Administration interface ------------------------------------------*/
740 /* --- @a_warn@ --- *
742 * Arguments: @const char *fmt@ = pointer to format string
743 * @...@ = other arguments
747 * Use: Informs all admin connections of a warning.
750 extern void a_warn(const char */*fmt*/, ...);
752 /* --- @a_create@ --- *
754 * Arguments: @int fd_in, fd_out@ = file descriptors to use
758 * Use: Creates a new admin connection.
761 extern void a_create(int /*fd_in*/, int /*fd_out*/);
763 /* --- @a_quit@ --- *
769 * Use: Shuts things down nicely.
772 extern void a_quit(void);
774 /* --- @a_daemon@ --- *
780 * Use: Informs the admin module that it's a daemon.
783 extern void a_daemon(void);
785 /* --- @a_init@ --- *
787 * Arguments: @const char *sock@ = socket name to create
791 * Use: Creates the admin listening socket.
794 extern void a_init(const char */*sock*/);
796 /*----- Peer management ---------------------------------------------------*/
798 /* --- @p_txstart@ --- *
800 * Arguments: @peer *p@ = pointer to peer block
801 * @unsigned msg@ = message type code
803 * Returns: A pointer to a buffer to write to.
805 * Use: Starts sending to a peer. Only one send can happen at a
809 extern buf *p_txstart(peer */*p*/, unsigned /*msg*/);
811 /* --- @p_txend@ --- *
813 * Arguments: @peer *p@ = pointer to peer block
817 * Use: Sends a packet to the peer.
820 extern void p_txend(peer */*p*/);
824 * Arguments: @peer *p@ = pointer to peer block
825 * @buf *b@ = buffer containing incoming packet
829 * Use: Handles a packet which needs to be sent to a peer.
832 extern void p_tun(peer */*p*/, buf */*b*/);
834 /* --- @p_interval@ --- *
840 * Use: Called periodically to do tidying.
843 extern void p_interval(void);
845 /* --- @p_stats@ --- *
847 * Arguments: @peer *p@ = pointer to a peer block
849 * Returns: A pointer to the peer's statistics.
852 extern stats *p_stats(peer */*p*/);
854 /* --- @p_ifname@ --- *
856 * Arguments: @peer *p@ = pointer to a peer block
858 * Returns: A pointer to the peer's interface name.
861 extern const char *p_ifname(peer */*p*/);
863 /* --- @p_addr@ --- *
865 * Arguments: @peer *p@ = pointer to a peer block
867 * Returns: A pointer to the peer's address.
870 extern const addr *p_addr(peer */*p*/);
872 /* --- @p_init@ --- *
874 * Arguments: @unsigned port@ = port number to listen to
878 * Use: Initializes the peer system; creates the socket.
881 extern void p_init(unsigned /*port*/);
883 /* --- @p_port@ --- *
887 * Returns: Port number used for socket.
890 unsigned p_port(void);
892 /* --- @p_create@ --- *
894 * Arguments: @const char *name@ = name for this peer
895 * @struct sockaddr *sa@ = socket address of peer
896 * @size_t sz@ = size of socket address
898 * Returns: Pointer to the peer block, or null if it failed.
900 * Use: Creates a new named peer block. No peer is actually attached
904 extern peer *p_create(const char */*name*/,
905 struct sockaddr */*sa*/, size_t /*sz*/);
907 /* --- @p_name@ --- *
909 * Arguments: @peer *p@ = pointer to a peer block
911 * Returns: A pointer to the peer's name.
914 extern const char *p_name(peer */*p*/);
916 /* --- @p_find@ --- *
918 * Arguments: @const char *name@ = name to look up
920 * Returns: Pointer to the peer block, or null if not found.
922 * Use: Finds a peer by name.
925 extern peer *p_find(const char */*name*/);
927 /* --- @p_destroy@ --- *
929 * Arguments: @peer *p@ = pointer to a peer
933 * Use: Destroys a peer.
936 extern void p_destroy(peer */*p*/);
938 /* --- @p_first@, @p_next@ --- *
940 * Arguments: @peer *p@ = a peer block
942 * Returns: @peer_first@ returns the first peer in some ordering;
943 * @peer_next@ returns the peer following a given one in the
944 * same ordering. Null is returned for the end of the list.
947 extern peer *p_first(void);
948 extern peer *p_next(peer */*p*/);
950 /*----- Tunnel interface --------------------------------------------------*/
952 /* --- @tun_init@ --- *
958 * Use: Initializes the tunneling system. Maybe this will require
959 * opening file descriptors or something.
962 extern void tun_init(void);
964 /* --- @tun_create@ --- *
966 * Arguments: @tunnel *t@ = pointer to tunnel block
967 * @peer *p@ = pointer to peer block
969 * Returns: Zero if it worked, nonzero on failure.
971 * Use: Initializes a new tunnel.
974 extern int tun_create(tunnel */*t*/, peer */*p*/);
976 /* --- @tun_ifname@ --- *
978 * Arguments: @tunnel *t@ = pointer to tunnel block
980 * Returns: A pointer to the tunnel's interface name.
983 extern const char *tun_ifname(tunnel */*t*/);
985 /* --- @tun_inject@ --- *
987 * Arguments: @tunnel *t@ = pointer to tunnel block
988 * @buf *b@ = buffer to send
992 * Use: Injects a packet into the local network stack.
995 extern void tun_inject(tunnel */*t*/, buf */*b*/);
997 /* --- @tun_destroy@ --- *
999 * Arguments: @tunnel *t@ = pointer to tunnel block
1003 * Use: Destroys a tunnel.
1006 extern void tun_destroy(tunnel */*t*/);
1008 /*----- Other handy utilities ---------------------------------------------*/
1010 /* --- @mpstr@ --- *
1012 * Arguments: @mp *m@ = a multiprecision integer
1014 * Returns: A pointer to the integer's textual representation.
1016 * Use: Converts a multiprecision integer to a string. Corrupts
1020 extern const char *mpstr(mp */*m*/);
1022 /* --- @timestr@ --- *
1024 * Arguments: @time_t t@ = a time to convert
1026 * Returns: A pointer to a textual representation of the time.
1028 * Use: Converts a time to a textual representation. Corrupts
1032 extern const char *timestr(time_t /*t*/);
1034 /*----- That's all, folks -------------------------------------------------*/