3 * $Id: tripe.h,v 1.12 2003/04/06 10:25:17 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 1.12 2003/04/06 10:25:17 mdw
33 * Support Linux TUN/TAP device. Fix some bugs.
35 * Revision 1.11 2002/01/13 14:57:42 mdw
38 * Revision 1.10 2002/01/13 14:54:58 mdw
41 * Revision 1.9 2001/06/22 19:40:36 mdw
42 * Support expiry of other peers' public keys.
44 * Revision 1.8 2001/06/19 22:10:57 mdw
45 * Some more constants for the algorithms. Document the packet format
46 * change for non-malleability. Moved @buf@ definitions to separate header
49 * Revision 1.7 2001/03/03 12:07:08 mdw
50 * Rename word get and put functions now that there's 16-bit support.
52 * Revision 1.6 2001/02/19 19:11:09 mdw
53 * Output buffering on admin connections.
55 * Revision 1.5 2001/02/16 21:41:43 mdw
56 * Major changes. See source files for details.
58 * Revision 1.4 2001/02/05 19:56:37 mdw
59 * Sequence number protection, and BSD tunnels.
61 * Revision 1.3 2001/02/04 01:17:55 mdw
62 * Create a configuration header file to tidy up command lines.
64 * Revision 1.2 2001/02/03 22:40:29 mdw
65 * Put timer information into the entropy pool when packets are received
66 * and on similar events. Reseed the generator on the interval timer.
68 * Revision 1.1 2001/02/03 20:26:37 mdw
80 /*----- Header files ------------------------------------------------------*/
95 #include <sys/types.h>
101 #include <sys/socket.h>
103 #include <netinet/in.h>
104 #include <arpa/inet.h>
107 #if TUN_TYPE == TUN_LINUX
108 # include <linux/if.h>
109 # include <linux/if_tun.h>
115 #include <mLib/alloc.h>
116 #include <mLib/arena.h>
117 #include <mLib/bres.h>
118 #include <mLib/dstr.h>
119 #include <mLib/env.h>
120 #include <mLib/fdflags.h>
121 #include <mLib/fwatch.h>
122 #include <mLib/mdwopt.h>
123 #include <mLib/quis.h>
124 #include <mLib/report.h>
125 #include <mLib/sel.h>
126 #include <mLib/selbuf.h>
127 #include <mLib/sig.h>
128 #include <mLib/str.h>
129 #include <mLib/sub.h>
130 #include <mLib/trace.h>
132 #include <catacomb/gcipher.h>
133 #include <catacomb/gmac.h>
134 #include <catacomb/grand.h>
135 #include <catacomb/key.h>
136 #include <catacomb/paranoia.h>
138 #include <catacomb/noise.h>
139 #include <catacomb/rand.h>
141 #include <catacomb/mp.h>
142 #include <catacomb/mpmont.h>
143 #include <catacomb/mprand.h>
144 #include <catacomb/dh.h>
151 /*----- Magic numbers -----------------------------------------------------*/
153 /* --- Tunnel types --- */
160 /* --- Trace flags --- */
168 #define T_KEYEXCH 64u
169 #define T_KEYMGMT 128u
175 #define SEC(n) (n##u)
176 #define MIN(n) (n##u * 60u)
177 #define MEG(n) (n##ul * 1024ul * 1024ul)
179 /* --- Other things --- */
181 #define PKBUFSZ 65536
183 /*----- TrIPE protocol ----------------------------------------------------*/
185 /* --- TrIPE message format --- *
187 * A packet begins with a single-byte message type. The top four bits are a
188 * category code used to send the message to the right general place in the
189 * code; the bottom bits identify the actual message type.
192 #define MSG_CATMASK 0xf0
193 #define MSG_TYPEMASK 0x0f
195 /* --- Encrypted message packets --- *
197 * Messages of category @MSG_PACKET@ contain encrypted network packets. The
198 * message content is a symmetric-encrypted block (see below). Reception of
199 * a packet encrypted under a new key implicitly permits that key to be used
200 * to send further packets.
202 * The only packet type accepted is zero.
204 * Packets may be encrypted under any live keyset, but should use the most
208 #define MSG_PACKET 0x00
210 /* --- Key exchange packets --- */
212 #define MSG_KEYEXCH 0x10
214 #define KX_PRECHAL 0u
219 #define KX_SWITCHOK 5u
222 /* --- Symmetric encryption and keysets --- *
224 * Packets consist of an 80-bit MAC, a 32-bit sequence number, and the
227 * The plaintext is encrypted using Blowfish in CBC mode with ciphertext
228 * stealing (as described in [Schneier]. The initialization vector is
229 * selected randomly, and prepended to the actual ciphertext.
231 * The MAC is computed using the HMAC construction with RIPEMD160 over the
232 * sequence number and the ciphertext (with IV); the first 80 bits of the
233 * output are used. (This is the minimum allowed by the draft FIPS for HMAC,
234 * and the recommended truncation.)
236 * A keyset consists of
238 * * an integrity (MAC) key;
239 * * a confidentiality (encryption) key; and
240 * * a sequence numbering space
242 * in each direction. The packets sent by a host encrypted under a
243 * particular keyset are assigned consecutive sequence numbers starting from
244 * zero. The receiving host must ensure that it only accepts each packet at
245 * most once. It should maintain a window of sequence numbers: packets with
246 * numbers beyond the end of the window are accepted and cause the window to
247 * be advanced; packets with numbers before the start of the window are
248 * rejected; packets with numbers which appear within the window are accepted
249 * only if the number has not been seen before.
251 * When a host sends a @KX_SWITCH@ or @KX_SWITCHOK@ message, it installs the
252 * newly-negotiated keyset in a `listen-only' state: it may not send a packet
253 * encrypted under the keyset until either it has received a @KX_SWITCH@ or
254 * @KX_SWITCHOK@ message, or a @MSG_PACKET@ encrypted under the keyset, from
258 /*----- Cipher selections -------------------------------------------------*/
260 #include <catacomb/blowfish.h>
261 #include <catacomb/blowfish-cbc.h>
262 #include <catacomb/blowfish-counter.h>
263 #include <catacomb/rmd160.h>
264 #include <catacomb/rmd160-hmac.h>
266 #define CIPHER (&blowfish_cbc)
267 #define MAC (&rmd160_hmac)
269 #define HASH_CTX rmd160_ctx
270 #define HASH_INIT rmd160_init
271 #define HASH rmd160_hash
272 #define HASH_STRING(c, s) HASH((c), s, sizeof(s))
273 #define HASH_DONE rmd160_done
274 #define HASHSZ RMD160_HASHSZ
276 #define MGF_CTX blowfish_counterctx
277 #define MGF_INIT blowfish_counterinit
278 #define MGF_CRYPT blowfish_counterencrypt
281 #define IVSZ BLOWFISH_BLKSZ
284 /*----- Data structures ---------------------------------------------------*/
286 /* --- Socket addresses --- *
288 * A magic union of supported socket addresses.
293 struct sockaddr_in sin;
296 /* --- A symmetric keyset --- *
298 * A keyset contains a set of symmetric keys for encrypting and decrypting
299 * packets. Keysets are stored in a list, sorted in reverse order of
300 * creation, so that the most recent keyset (the one most likely to be used)
303 * Each keyset has a time limit and a data limit. The keyset is destroyed
304 * when either it has existed for too long, or it has been used to encrypt
305 * too much data. New key exchanges are triggered when keys are close to
309 typedef struct keyset {
310 struct keyset *next; /* Next active keyset in the list */
311 unsigned ref; /* Reference count for keyset */
312 time_t t_exp; /* Expiry time for this keyset */
313 unsigned long sz_exp; /* Data limit for the keyset */
314 T( unsigned seq; ) /* Sequence number for tracing */
315 unsigned f; /* Various useful flags */
316 gcipher *cin, *cout; /* Keyset ciphers for encryption */
317 gmac *min, *mout; /* Keyset MACs for integrity */
318 uint32 oseq; /* Outbound sequence number */
319 uint32 iseq, iwin; /* Inbound sequence number */
322 #define KS_SEQWINSZ 32 /* Bits in sequence number window */
324 #define KSF_LISTEN 1u /* Don't encrypt packets yet */
325 #define KSF_LINK 2u /* Key is in a linked list */
327 /* --- Key exchange --- *
329 * TrIPE uses the Wrestlers Protocol for its key exchange. The Wrestlers
330 * Protocol has a number of desirable features (e.g., perfect forward
331 * secrecy, and zero-knowledge authentication) which make it attractive for
332 * use in TrIPE. The Wrestlers Protocol was designed by Mark Wooding and
339 typedef struct kxchal {
340 struct keyexch *kx; /* Pointer back to key exchange */
341 mp *c; /* Responder's challenge */
342 mp *r; /* My reply to the challenge */
343 keyset *ks; /* Pointer to temporary keyset */
344 unsigned f; /* Various useful flags */
345 sel_timer t; /* Response timer for challenge */
346 octet hc[HASHSZ]; /* Hash of his challenge */
347 mp *ck; /* The check value */
348 octet hswrq_in[HASHSZ]; /* Inbound switch request message */
349 octet hswok_in[HASHSZ]; /* Inbound switch confirmation */
350 octet hswrq_out[HASHSZ]; /* Outbound switch request message */
351 octet hswok_out[HASHSZ]; /* Outbound switch confirmation */
354 typedef struct keyexch {
355 struct peer *p; /* Pointer back to the peer */
356 keyset **ks; /* Peer's list of keysets */
357 unsigned f; /* Various useful flags */
358 unsigned s; /* Current state in exchange */
359 sel_timer t; /* Timer for next exchange */
360 dh_pub kpub; /* Peer's public key */
361 time_t texp_kpub; /* Expiry time for public key */
362 mp *alpha; /* My temporary secret */
363 mp *c; /* My challenge */
364 mp *rx; /* The expected response */
365 unsigned nr; /* Number of extant responses */
366 time_t t_valid; /* When this exchange goes bad */
367 octet hc[HASHSZ]; /* Hash of my challenge */
368 kxchal *r[KX_NCHAL]; /* Array of challenges */
371 #define KXF_TIMER 1u /* Waiting for a timer to go off */
372 #define KXF_DEAD 2u /* The key-exchanger isn't up */
373 #define KXF_PUBKEY 4u /* Key exchanger has a public key */
376 KXS_DEAD, /* Uninitialized state (magical) */
377 KXS_CHAL, /* Main answer-challenges state */
378 KXS_COMMIT, /* Committed: send switch request */
379 KXS_SWITCH /* Switched: send confirmation */
382 /* --- Tunnel structure --- *
384 * Used to maintain system-specific information about the tunnel interface.
387 typedef struct tunnel {
388 #if TUN_TYPE == TUN_UNET
389 sel_file f; /* Selector for Usernet device */
390 struct peer *p; /* Pointer to my peer */
391 #elif TUN_TYPE == TUN_LINUX
392 sel_file f; /* Selector for TUN/TAP device */
393 struct peer *p; /* Pointer to my peer */
394 char ifn[IFNAMSIZ]; /* Interface name buffer */
395 #elif TUN_TYPE == TUN_BSD
396 sel_file f; /* Selector for tunnel device */
397 struct peer *p; /* Pointer to my peer */
398 unsigned n; /* Number of my tunnel device */
400 # error "No support for this tunnel type"
404 /* --- Peer statistics --- *
406 * Contains various interesting and not-so-interesting statistics about a
407 * peer. This is updated by various parts of the code. The format of the
408 * structure isn't considered private, and @p_stats@ returns a pointer to the
409 * statistics block for a given peer.
412 typedef struct stats {
413 unsigned long sz_in, sz_out; /* Size of all data in and out */
414 unsigned long sz_kxin, sz_kxout; /* Size of key exchange messages */
415 unsigned long sz_ipin, sz_ipout; /* Size of encapsulated IP packets */
416 time_t t_start, t_last; /* Time peer created, last recv */
417 unsigned long n_reject; /* Number of rejected packets */
418 unsigned long n_in, n_out; /* Number of packets in and out */
419 unsigned long n_kxin, n_kxout; /* Number of key exchange packets */
420 unsigned long n_ipin, n_ipout; /* Number of encrypted packets */
423 /* --- Peer structure --- *
425 * The main structure which glues everything else together.
428 typedef struct peer {
429 struct peer *next, *prev; /* Links to next and previous */
430 char *name; /* Name of this peer */
431 tunnel t; /* Tunnel for local packets */
432 keyset *ks; /* List head for keysets */
433 buf b; /* Buffer for sending packets */
434 addr peer; /* Peer socket address */
435 size_t sasz; /* Socket address size */
436 stats st; /* Statistics */
437 keyexch kx; /* Key exchange protocol block */
440 /* --- Admin structure --- */
442 #define OBUFSZ 16384u
444 typedef struct obuf {
445 struct obuf *next; /* Next buffer in list */
446 char *p_in, *p_out; /* Pointers into the buffer */
447 char buf[OBUFSZ]; /* The actual buffer */
450 typedef struct admin {
451 struct admin *next, *prev; /* Links to next and previous */
452 unsigned f; /* Various useful flags */
454 unsigned seq; /* Sequence number for tracing */
456 char *pname; /* Peer name to create */
457 char *paddr; /* Address string to resolve */
458 obuf *o_head, *o_tail; /* Output buffer list */
459 selbuf b; /* Line buffer for commands */
460 sel_file w; /* Selector for write buffering */
461 bres_client r; /* Background resolver task */
462 sel_timer t; /* Timer for resolver */
463 addr peer; /* Address to set */
464 size_t sasz; /* Size of the address */
467 #define AF_DEAD 1u /* Destroy this admin block */
468 #define AF_LOCK 2u /* Don't destroy it yet */
470 /*----- Global variables --------------------------------------------------*/
472 extern sel_state sel; /* Global I/O event state */
473 extern dh_priv kpriv; /* Our private key */
474 extern mpmont mg; /* Montgomery context for DH group */
475 extern octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ];
478 extern const trace_opt tr_opts[]; /* Trace options array */
479 extern unsigned tr_flags; /* Trace options flags */
482 /*----- Other macros ------------------------------------------------------*/
484 #define TIMER noise_timer(RAND_GLOBAL)
486 /*----- Key management ----------------------------------------------------*/
488 /* --- @km_interval@ --- *
492 * Returns: Zero if OK, nonzero to force reloading of keys.
494 * Use: Called on the interval timer to perform various useful jobs.
497 extern int km_interval(void);
499 /* --- @km_init@ --- *
501 * Arguments: @const char *kr_priv@ = private keyring file
502 * @const char *kr_pub@ = public keyring file
503 * @const char *tag@ = tag to load
507 * Use: Initializes, and loads the private key.
510 extern void km_init(const char */*kr_priv*/, const char */*kr_pub*/,
511 const char */*tag*/);
513 /* --- @km_getpubkey@ --- *
515 * Arguments: @const char *tag@ = public key tag to load
516 * @dh_pub *kpub@ = where to put the public key
517 * @time_t *t_exp@ = where to put the expiry time
519 * Returns: Zero if OK, nonzero if it failed.
521 * Use: Fetches a public key from the keyring.
524 extern int km_getpubkey(const char */*tag*/, dh_pub */*kpub*/,
527 /*----- Key exchange ------------------------------------------------------*/
529 /* --- @kx_start@ --- *
531 * Arguments: @keyexch *kx@ = pointer to key exchange context
535 * Use: Stimulates a key exchange. If a key exchage is in progress,
536 * a new challenge is sent (unless the quiet timer forbids
537 * this); if no exchange is in progress, one is commenced.
540 extern void kx_start(keyexch */*kx*/);
542 /* --- @kx_message@ --- *
544 * Arguments: @keyexch *kx@ = pointer to key exchange context
545 * @unsigned msg@ = the message code
546 * @buf *b@ = pointer to buffer containing the packet
550 * Use: Reads a packet containing key exchange messages and handles
554 extern void kx_message(keyexch */*kx*/, unsigned /*msg*/, buf */*b*/);
556 /* --- @kx_free@ --- *
558 * Arguments: @keyexch *kx@ = pointer to key exchange context
562 * Use: Frees everything in a key exchange context.
565 extern void kx_free(keyexch */*kx*/);
567 /* --- @kx_newkeys@ --- *
569 * Arguments: @keyexch *kx@ = pointer to key exchange context
573 * Use: Informs the key exchange module that its keys may have
574 * changed. If fetching the new keys fails, the peer will be
575 * destroyed, we log messages and struggle along with the old
579 extern void kx_newkeys(keyexch */*kx*/);
581 /* --- @kx_init@ --- *
583 * Arguments: @keyexch *kx@ = pointer to key exchange context
584 * @peer *p@ = pointer to peer context
585 * @keyset **ks@ = pointer to keyset list
587 * Returns: Zero if OK, nonzero if it failed.
589 * Use: Initializes a key exchange module. The module currently
590 * contains no keys, and will attempt to initiate a key
594 extern int kx_init(keyexch */*kx*/, peer */*p*/, keyset **/*ks*/);
596 /*----- Keysets and symmetric cryptography --------------------------------*/
598 /* --- @ks_drop@ --- *
600 * Arguments: @keyset *ks@ = pointer to a keyset
604 * Use: Decrements a keyset's reference counter. If the counter hits
605 * zero, the keyset is freed.
608 extern void ks_drop(keyset */*ks*/);
610 /* --- @ks_gen@ --- *
612 * Arguments: @const void *k@ = pointer to key material
613 * @size_t x, y, z@ = offsets into key material (see below)
615 * Returns: A pointer to the new keyset.
617 * Use: Derives a new keyset from the given key material. The
618 * offsets @x@, @y@ and @z@ separate the key material into three
619 * parts. Between the @k@ and @k + x@ is `my' contribution to
620 * the key material; between @k + x@ and @k + y@ is `your'
621 * contribution; and between @k + y@ and @k + z@ is a shared
622 * value we made together. These are used to construct two
623 * pairs of symmetric keys. Each pair consists of an encryption
624 * key and a message authentication key. One pair is used for
625 * outgoing messages, the other for incoming messages.
627 * The new key is marked so that it won't be selected for output
628 * by @ksl_encrypt@. You can still encrypt data with it by
629 * calling @ks_encrypt@ directly.
632 extern keyset *ks_gen(const void */*k*/,
633 size_t /*x*/, size_t /*y*/, size_t /*z*/);
635 /* --- @ks_tregen@ --- *
637 * Arguments: @keyset *ks@ = pointer to a keyset
639 * Returns: The time at which moves ought to be made to replace this key.
642 extern time_t ks_tregen(keyset */*ks*/);
644 /* --- @ks_activate@ --- *
646 * Arguments: @keyset *ks@ = pointer to a keyset
650 * Use: Activates a keyset, so that it can be used for encrypting
654 extern void ks_activate(keyset */*ks*/);
656 /* --- @ks_encrypt@ --- *
658 * Arguments: @keyset *ks@ = pointer to a keyset
659 * @buf *b@ = pointer to input buffer
660 * @buf *bb@ = pointer to output buffer
662 * Returns: Zero if OK, nonzero if the key needs replacing. If the
663 * encryption failed, the output buffer is broken and zero is
666 * Use: Encrypts a block of data using the key. Note that the `key
667 * ought to be replaced' notification is only ever given once
668 * for each key. Also note that this call forces a keyset to be
669 * used even if it's marked as not for data output.
672 extern int ks_encrypt(keyset */*ks*/, buf */*b*/, buf */*bb*/);
674 /* --- @ks_decrypt@ --- *
676 * Arguments: @keyset *ks@ = pointer to a keyset
677 * @buf *b@ = pointer to an input buffer
678 * @buf *bb@ = pointer to an output buffer
680 * Returns: Zero on success, or nonzero if there was some problem.
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.
687 extern int ks_decrypt(keyset */*ks*/, buf */*b*/, buf */*bb*/);
689 /* --- @ksl_free@ --- *
691 * Arguments: @keyset **ksroot@ = pointer to keyset list head
695 * Use: Frees (releases references to) all of the keys in a keyset.
698 extern void ksl_free(keyset **/*ksroot*/);
700 /* --- @ksl_link@ --- *
702 * Arguments: @keyset **ksroot@ = pointer to keyset list head
703 * @keyset *ks@ = pointer to a keyset
707 * Use: Links a keyset into a list. A keyset can only be on one list
708 * at a time. Bad things happen otherwise.
711 extern void ksl_link(keyset **/*ksroot*/, keyset */*ks*/);
713 /* --- @ksl_prune@ --- *
715 * Arguments: @keyset **ksroot@ = pointer to keyset list head
719 * Use: Prunes the keyset list by removing keys which mustn't be used
723 extern void ksl_prune(keyset **/*ksroot*/);
725 /* --- @ksl_encrypt@ --- *
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 a new key is needed.
733 * Use: Encrypts a packet.
736 extern int ksl_encrypt(keyset **/*ksroot*/, buf */*b*/, buf */*bb*/);
738 /* --- @ksl_decrypt@ --- *
740 * Arguments: @keyset **ksroot@ = pointer to keyset list head
741 * @buf *b@ = pointer to input buffer
742 * @buf *bb@ = pointer to output buffer
744 * Returns: Nonzero if the packet couldn't be decrypted.
746 * Use: Decrypts a packet.
749 extern int ksl_decrypt(keyset **/*ksroot*/, buf */*b*/, buf */*bb*/);
751 /*----- Administration interface ------------------------------------------*/
753 /* --- @a_warn@ --- *
755 * Arguments: @const char *fmt@ = pointer to format string
756 * @...@ = other arguments
760 * Use: Informs all admin connections of a warning.
763 extern void a_warn(const char */*fmt*/, ...);
765 /* --- @a_create@ --- *
767 * Arguments: @int fd_in, fd_out@ = file descriptors to use
771 * Use: Creates a new admin connection.
774 extern void a_create(int /*fd_in*/, int /*fd_out*/);
776 /* --- @a_quit@ --- *
782 * Use: Shuts things down nicely.
785 extern void a_quit(void);
787 /* --- @a_daemon@ --- *
793 * Use: Informs the admin module that it's a daemon.
796 extern void a_daemon(void);
798 /* --- @a_init@ --- *
800 * Arguments: @const char *sock@ = socket name to create
804 * Use: Creates the admin listening socket.
807 extern void a_init(const char */*sock*/);
809 /*----- Peer management ---------------------------------------------------*/
811 /* --- @p_txstart@ --- *
813 * Arguments: @peer *p@ = pointer to peer block
814 * @unsigned msg@ = message type code
816 * Returns: A pointer to a buffer to write to.
818 * Use: Starts sending to a peer. Only one send can happen at a
822 extern buf *p_txstart(peer */*p*/, unsigned /*msg*/);
824 /* --- @p_txend@ --- *
826 * Arguments: @peer *p@ = pointer to peer block
830 * Use: Sends a packet to the peer.
833 extern void p_txend(peer */*p*/);
837 * Arguments: @peer *p@ = pointer to peer block
838 * @buf *b@ = buffer containing incoming packet
842 * Use: Handles a packet which needs to be sent to a peer.
845 extern void p_tun(peer */*p*/, buf */*b*/);
847 /* --- @p_interval@ --- *
853 * Use: Called periodically to do tidying.
856 extern void p_interval(void);
858 /* --- @p_stats@ --- *
860 * Arguments: @peer *p@ = pointer to a peer block
862 * Returns: A pointer to the peer's statistics.
865 extern stats *p_stats(peer */*p*/);
867 /* --- @p_ifname@ --- *
869 * Arguments: @peer *p@ = pointer to a peer block
871 * Returns: A pointer to the peer's interface name.
874 extern const char *p_ifname(peer */*p*/);
876 /* --- @p_addr@ --- *
878 * Arguments: @peer *p@ = pointer to a peer block
880 * Returns: A pointer to the peer's address.
883 extern const addr *p_addr(peer */*p*/);
885 /* --- @p_init@ --- *
887 * Arguments: @unsigned port@ = port number to listen to
891 * Use: Initializes the peer system; creates the socket.
894 extern void p_init(unsigned /*port*/);
896 /* --- @p_port@ --- *
900 * Returns: Port number used for socket.
903 unsigned p_port(void);
905 /* --- @p_create@ --- *
907 * Arguments: @const char *name@ = name for this peer
908 * @struct sockaddr *sa@ = socket address of peer
909 * @size_t sz@ = size of socket address
911 * Returns: Pointer to the peer block, or null if it failed.
913 * Use: Creates a new named peer block. No peer is actually attached
917 extern peer *p_create(const char */*name*/,
918 struct sockaddr */*sa*/, size_t /*sz*/);
920 /* --- @p_name@ --- *
922 * Arguments: @peer *p@ = pointer to a peer block
924 * Returns: A pointer to the peer's name.
927 extern const char *p_name(peer */*p*/);
929 /* --- @p_find@ --- *
931 * Arguments: @const char *name@ = name to look up
933 * Returns: Pointer to the peer block, or null if not found.
935 * Use: Finds a peer by name.
938 extern peer *p_find(const char */*name*/);
940 /* --- @p_destroy@ --- *
942 * Arguments: @peer *p@ = pointer to a peer
946 * Use: Destroys a peer.
949 extern void p_destroy(peer */*p*/);
951 /* --- @p_first@, @p_next@ --- *
953 * Arguments: @peer *p@ = a peer block
955 * Returns: @peer_first@ returns the first peer in some ordering;
956 * @peer_next@ returns the peer following a given one in the
957 * same ordering. Null is returned for the end of the list.
960 extern peer *p_first(void);
961 extern peer *p_next(peer */*p*/);
963 /*----- Tunnel interface --------------------------------------------------*/
965 /* --- @tun_init@ --- *
971 * Use: Initializes the tunneling system. Maybe this will require
972 * opening file descriptors or something.
975 extern void tun_init(void);
977 /* --- @tun_create@ --- *
979 * Arguments: @tunnel *t@ = pointer to tunnel block
980 * @peer *p@ = pointer to peer block
982 * Returns: Zero if it worked, nonzero on failure.
984 * Use: Initializes a new tunnel.
987 extern int tun_create(tunnel */*t*/, peer */*p*/);
989 /* --- @tun_ifname@ --- *
991 * Arguments: @tunnel *t@ = pointer to tunnel block
993 * Returns: A pointer to the tunnel's interface name.
996 extern const char *tun_ifname(tunnel */*t*/);
998 /* --- @tun_inject@ --- *
1000 * Arguments: @tunnel *t@ = pointer to tunnel block
1001 * @buf *b@ = buffer to send
1005 * Use: Injects a packet into the local network stack.
1008 extern void tun_inject(tunnel */*t*/, buf */*b*/);
1010 /* --- @tun_destroy@ --- *
1012 * Arguments: @tunnel *t@ = pointer to tunnel block
1016 * Use: Destroys a tunnel.
1019 extern void tun_destroy(tunnel */*t*/);
1021 /*----- Other handy utilities ---------------------------------------------*/
1023 /* --- @mpstr@ --- *
1025 * Arguments: @mp *m@ = a multiprecision integer
1027 * Returns: A pointer to the integer's textual representation.
1029 * Use: Converts a multiprecision integer to a string. Corrupts
1033 extern const char *mpstr(mp */*m*/);
1035 /* --- @timestr@ --- *
1037 * Arguments: @time_t t@ = a time to convert
1039 * Returns: A pointer to a textual representation of the time.
1041 * Use: Converts a time to a textual representation. Corrupts
1045 extern const char *timestr(time_t /*t*/);
1047 /*----- That's all, folks -------------------------------------------------*/