3 * $Id: tripe.h,v 1.8 2001/06/19 22:10:57 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 1.8 2001/06/19 22:10:57 mdw
33 * Some more constants for the algorithms. Document the packet format
34 * change for non-malleability. Moved @buf@ definitions to separate header
37 * Revision 1.7 2001/03/03 12:07:08 mdw
38 * Rename word get and put functions now that there's 16-bit support.
40 * Revision 1.6 2001/02/19 19:11:09 mdw
41 * Output buffering on admin connections.
43 * Revision 1.5 2001/02/16 21:41:43 mdw
44 * Major changes. See source files for details.
46 * Revision 1.4 2001/02/05 19:56:37 mdw
47 * Sequence number protection, and BSD tunnels.
49 * Revision 1.3 2001/02/04 01:17:55 mdw
50 * Create a configuration header file to tidy up command lines.
52 * Revision 1.2 2001/02/03 22:40:29 mdw
53 * Put timer information into the entropy pool when packets are received
54 * and on similar events. Reseed the generator on the interval timer.
56 * Revision 1.1 2001/02/03 20:26:37 mdw
68 /*----- Header files ------------------------------------------------------*/
83 #include <sys/types.h>
89 #include <sys/socket.h>
91 #include <netinet/in.h>
92 #include <arpa/inet.h>
98 #include <mLib/alloc.h>
99 #include <mLib/arena.h>
100 #include <mLib/bres.h>
101 #include <mLib/dstr.h>
102 #include <mLib/env.h>
103 #include <mLib/fdflags.h>
104 #include <mLib/fwatch.h>
105 #include <mLib/mdwopt.h>
106 #include <mLib/quis.h>
107 #include <mLib/report.h>
108 #include <mLib/sel.h>
109 #include <mLib/selbuf.h>
110 #include <mLib/sig.h>
111 #include <mLib/str.h>
112 #include <mLib/sub.h>
113 #include <mLib/trace.h>
115 #include <catacomb/gcipher.h>
116 #include <catacomb/gmac.h>
117 #include <catacomb/grand.h>
118 #include <catacomb/key.h>
119 #include <catacomb/paranoia.h>
121 #include <catacomb/noise.h>
122 #include <catacomb/rand.h>
124 #include <catacomb/mp.h>
125 #include <catacomb/mpmont.h>
126 #include <catacomb/mprand.h>
127 #include <catacomb/dh.h>
134 /*----- Magic numbers -----------------------------------------------------*/
136 /* --- Tunnel types --- */
142 /* --- Trace flags --- */
150 #define T_KEYEXCH 64u
151 #define T_KEYMGMT 128u
157 #define SEC(n) (n##u)
158 #define MIN(n) (n##u * 60u)
159 #define MEG(n) (n##ul * 1024ul * 1024ul)
161 /* --- Other things --- */
163 #define PKBUFSZ 65536
165 /*----- TrIPE protocol ----------------------------------------------------*/
167 /* --- TrIPE message format --- *
169 * A packet begins with a single-byte message type. The top four bits are a
170 * category code used to send the message to the right general place in the
171 * code; the bottom bits identify the actual message type.
174 #define MSG_CATMASK 0xf0
175 #define MSG_TYPEMASK 0x0f
177 /* --- Encrypted message packets --- *
179 * Messages of category @MSG_PACKET@ contain encrypted network packets. The
180 * message content is a symmetric-encrypted block (see below). Reception of
181 * a packet encrypted under a new key implicitly permits that key to be used
182 * to send further packets.
184 * The only packet type accepted is zero.
186 * Packets may be encrypted under any live keyset, but should use the most
190 #define MSG_PACKET 0x00
192 /* --- Key exchange packets --- */
194 #define MSG_KEYEXCH 0x10
196 #define KX_PRECHAL 0u
201 #define KX_SWITCHOK 5u
204 /* --- Symmetric encryption and keysets --- *
206 * Packets consist of an 80-bit MAC, a 32-bit sequence number, and the
209 * The plaintext is encrypted using Blowfish in CBC mode with ciphertext
210 * stealing (as described in [Schneier]. The initialization vector is
211 * selected randomly, and prepended to the actual ciphertext.
213 * The MAC is computed using the HMAC construction with RIPEMD160 over the
214 * sequence number and the ciphertext (with iV); the first 80 bits of the
215 * output are used. (This is the minimum allowed by the draft FIPS for HMAC,
216 * and the recommended truncation.)
218 * A keyset consists of
220 * * an integrity (MAC) key;
221 * * a confidentiality (encryption) key; and
222 * * a sequence numbering space
224 * in each direction. The packets sent by a host encrypted under a
225 * particular keyset are assigned consecutive sequence numbers starting from
226 * zero. The receiving host must ensure that it only accepts each packet at
227 * most once. It should maintain a window of sequence numbers: packets with
228 * numbers beyond the end of the window are accepted and cause the window to
229 * be advanced; packets with numbers before the start of the window are
230 * rejected; packets with numbers which appear within the window are accepted
231 * only if the number has not been seen before.
233 * When a host sends a @KX_SWITCH@ or @KX_SWITCHOK@ message, it installs the
234 * newly-negotiated keyset in a `listen-only' state: it may not send a packet
235 * encrypted under the keyset until either it has received a @KX_SWITCH@ or
236 * @KX_SWITCHOK@ message, or a @MSG_PACKET@ encrypted under the keyset, from
240 /*----- Cipher selections -------------------------------------------------*/
242 #include <catacomb/blowfish.h>
243 #include <catacomb/blowfish-cbc.h>
244 #include <catacomb/rmd160.h>
245 #include <catacomb/rmd160-hmac.h>
247 #define CIPHER (&blowfish_cbc)
248 #define MAC (&rmd160_hmac)
250 #define HASH_CTX rmd160_ctx
251 #define HASH_INIT rmd160_init
252 #define HASH rmd160_hash
253 #define HASH_STRING(c, s) HASH((c), s, sizeof(s))
254 #define HASH_DONE rmd160_done
255 #define HASHSZ RMD160_HASHSZ
258 #define IVSZ BLOWFISH_BLKSZ
261 /*----- Data structures ---------------------------------------------------*/
263 /* --- Socket addresses --- *
265 * A magic union of supported socket addresses.
270 struct sockaddr_in sin;
273 /* --- A symmetric keyset --- *
275 * A keyset contains a set of symmetric keys for encrypting and decrypting
276 * packets. Keysets are stored in a list, sorted in reverse order of
277 * creation, so that the most recent keyset (the one most likely to be used)
280 * Each keyset has a time limit and a data limit. The keyset is destroyed
281 * when either it has existed for too long, or it has been used to encrypt
282 * too much data. New key exchanges are triggered when keys are close to
286 typedef struct keyset {
287 struct keyset *next; /* Next active keyset in the list */
288 unsigned ref; /* Reference count for keyset */
289 time_t t_exp; /* Expiry time for this keyset */
290 unsigned long sz_exp; /* Data limit for the keyset */
291 T( unsigned seq; ) /* Sequence number for tracing */
292 unsigned f; /* Various useful flags */
293 gcipher *cin, *cout; /* Keyset ciphers for encryption */
294 gmac *min, *mout; /* Keyset MACs for integrity */
295 uint32 oseq; /* Outbound sequence number */
296 uint32 iseq, iwin; /* Inbound sequence number */
299 #define KS_SEQWINSZ 32 /* Bits in sequence number window */
301 #define KSF_LISTEN 1u /* Don't encrypt packets yet */
302 #define KSF_LINK 2u /* Key is in a linked list */
304 /* --- Key exchange --- *
306 * TrIPE uses the Wrestlers Protocol for its key exchange. The Wrestlers
307 * Protocol has a number of desirable features (e.g., perfect forward
308 * secrecy, and zero-knowledge authentication) which make it attractive for
309 * use in TrIPE. The Wrestlers Protocol was designed by Mark Wooding and
316 typedef struct kxchal {
317 struct keyexch *kx; /* Pointer back to key exchange */
318 mp *c; /* Responder's challenge */
319 mp *r; /* My reply to the challenge */
320 keyset *ks; /* Pointer to temporary keyset */
321 unsigned f; /* Various useful flags */
322 sel_timer t; /* Response timer for challenge */
323 octet hc[HASHSZ]; /* Hash of his challenge */
324 octet hrx[HASHSZ]; /* My expected reply hash */
325 octet hswrq_in[HASHSZ]; /* Inbound switch request message */
326 octet hswok_in[HASHSZ]; /* Inbound switch confirmation */
327 octet hswrq_out[HASHSZ]; /* Outbound switch request message */
328 octet hswok_out[HASHSZ]; /* Outbound switch confirmation */
331 typedef struct keyexch {
332 struct peer *p; /* Pointer back to the peer */
333 keyset **ks; /* Peer's list of keysets */
334 unsigned f; /* Various useful flags */
335 unsigned s; /* Current state in exchange */
336 sel_timer t; /* Timer for next exchange */
337 dh_pub kpub; /* Peer's public key */
338 mp *alpha; /* My temporary secret */
339 mp *c; /* My challenge */
340 mp *rx; /* The expected response */
341 unsigned nr; /* Number of extant responses */
342 time_t t_valid; /* When this exchange goes bad */
343 octet hc[HASHSZ]; /* Hash of my challenge */
344 kxchal *r[KX_NCHAL]; /* Array of challenges */
347 #define KXF_TIMER 1u /* Waiting for a timer to go off */
350 KXS_DEAD, /* Uninitialized state (magical) */
351 KXS_CHAL, /* Main answer-challenges state */
352 KXS_COMMIT, /* Committed: send switch request */
353 KXS_SWITCH /* Switched: send confirmation */
356 /* --- Tunnel structure --- *
358 * Used to maintain system-specific information about the tunnel interface.
361 typedef struct tunnel {
362 #if TUN_TYPE == TUN_UNET
363 sel_file f; /* Selector for Usernet device */
364 struct peer *p; /* Pointer to my peer */
365 #elif TUN_TYPE == TUN_BSD
366 sel_file f; /* Selector for tunnel device */
367 struct peer *p; /* Pointer to my peer */
368 unsigned n; /* Number of my tunnel device */
370 # error "No support for this tunnel type"
374 /* --- Peer statistics --- *
376 * Contains various interesting and not-so-interesting statistics about a
377 * peer. This is updated by various parts of the code. The format of the
378 * structure isn't considered private, and @p_stats@ returns a pointer to the
379 * statistics block for a given peer.
382 typedef struct stats {
383 unsigned long sz_in, sz_out; /* Size of all data in and out */
384 unsigned long sz_kxin, sz_kxout; /* Size of key exchange messages */
385 unsigned long sz_ipin, sz_ipout; /* Size of encapsulated IP packets */
386 time_t t_start, t_last; /* Time peer created, last recv */
387 unsigned long n_reject; /* Number of rejected packets */
388 unsigned long n_in, n_out; /* Number of packets in and out */
389 unsigned long n_kxin, n_kxout; /* Number of key exchange packets */
390 unsigned long n_ipin, n_ipout; /* Number of encrypted packets */
393 /* --- Peer structure --- *
395 * The main structure which glues everything else together.
398 typedef struct peer {
399 struct peer *next, *prev; /* Links to next and previous */
400 char *name; /* Name of this peer */
401 tunnel t; /* Tunnel for local packets */
402 keyset *ks; /* List head for keysets */
403 buf b; /* Buffer for sending packets */
404 addr peer; /* Peer socket address */
405 size_t sasz; /* Socket address size */
406 stats st; /* Statistics */
407 keyexch kx; /* Key exchange protocol block */
410 /* --- Admin structure --- */
412 #define OBUFSZ 16384u
414 typedef struct obuf {
415 struct obuf *next; /* Next buffer in list */
416 char *p_in, *p_out; /* Pointers into the buffer */
417 char buf[OBUFSZ]; /* The actual buffer */
420 typedef struct admin {
421 struct admin *next, *prev; /* Links to next and previous */
422 unsigned f; /* Various useful flags */
424 unsigned seq; /* Sequence number for tracing */
426 char *pname; /* Peer name to create */
427 char *paddr; /* Address string to resolve */
428 obuf *o_head, *o_tail; /* Output buffer list */
429 selbuf b; /* Line buffer for commands */
430 sel_file w; /* Selector for write buffering */
431 bres_client r; /* Background resolver task */
432 sel_timer t; /* Timer for resolver */
433 addr peer; /* Address to set */
434 size_t sasz; /* Size of the address */
437 #define AF_DEAD 1u /* Destroy this admin block */
438 #define AF_LOCK 2u /* Don't destroy it yet */
440 /*----- Global variables --------------------------------------------------*/
442 extern sel_state sel; /* Global I/O event state */
443 extern dh_priv kpriv; /* Our private key */
444 extern mpmont mg; /* Montgomery context for DH group */
445 extern octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ];
448 extern const trace_opt tr_opts[]; /* Trace options array */
449 extern unsigned tr_flags; /* Trace options flags */
452 /*----- Other macros ------------------------------------------------------*/
454 #define TIMER noise_timer(RAND_GLOBAL)
456 /*----- Key management ----------------------------------------------------*/
458 /* --- @km_interval@ --- *
462 * Returns: Zero if OK, nonzero to force reloading of keys.
464 * Use: Called on the interval timer to perform various useful jobs.
467 extern int km_interval(void);
469 /* --- @km_init@ --- *
471 * Arguments: @const char *kr_priv@ = private keyring file
472 * @const char *kr_pub@ = public keyring file
473 * @const char *tag@ = tag to load
477 * Use: Initializes, and loads the private key.
480 extern void km_init(const char */*kr_priv*/, const char */*kr_pub*/,
481 const char */*tag*/);
483 /* --- @km_getpubkey@ --- *
485 * Arguments: @const char *tag@ = public key tag to load
486 * @dh_pub *kpub@ = where to put the public key
488 * Returns: Zero if OK, nonzero if it failed.
490 * Use: Fetches a public key from the keyring.
493 extern int km_getpubkey(const char */*tag*/, dh_pub */*kpub*/);
495 /*----- Key exchange ------------------------------------------------------*/
497 /* --- @kx_start@ --- *
499 * Arguments: @keyexch *kx@ = pointer to key exchange context
503 * Use: Stimulates a key exchange. If a key exchage is in progress,
504 * a new challenge is sent (unless the quiet timer forbids
505 * this); if no exchange is in progress, one is commenced.
508 extern void kx_start(keyexch */*kx*/);
510 /* --- @kx_message@ --- *
512 * Arguments: @keyexch *kx@ = pointer to key exchange context
513 * @unsigned msg@ = the message code
514 * @buf *b@ = pointer to buffer containing the packet
518 * Use: Reads a packet containing key exchange messages and handles
522 extern void kx_message(keyexch */*kx*/, unsigned /*msg*/, buf */*b*/);
524 /* --- @kx_free@ --- *
526 * Arguments: @keyexch *kx@ = pointer to key exchange context
530 * Use: Frees everything in a key exchange context.
533 extern void kx_free(keyexch */*kx*/);
535 /* --- @kx_newkeys@ --- *
537 * Arguments: @keyexch *kx@ = pointer to key exchange context
541 * Use: Informs the key exchange module that its keys may have
542 * changed. If fetching the new keys fails, the peer will be
543 * destroyed, we log messages and struggle along with the old
547 extern void kx_newkeys(keyexch */*kx*/);
549 /* --- @kx_init@ --- *
551 * Arguments: @keyexch *kx@ = pointer to key exchange context
552 * @peer *p@ = pointer to peer context
553 * @keyset **ks@ = pointer to keyset list
555 * Returns: Zero if OK, nonzero if it failed.
557 * Use: Initializes a key exchange module. The module currently
558 * contains no keys, and will attempt to initiate a key
562 extern int kx_init(keyexch */*kx*/, peer */*p*/, keyset **/*ks*/);
564 /*----- Keysets and symmetric cryptography --------------------------------*/
566 /* --- @ks_drop@ --- *
568 * Arguments: @keyset *ks@ = pointer to a keyset
572 * Use: Decrements a keyset's reference counter. If the counter hits
573 * zero, the keyset is freed.
576 extern void ks_drop(keyset */*ks*/);
578 /* --- @ks_gen@ --- *
580 * Arguments: @const void *k@ = pointer to key material
581 * @size_t x, y, z@ = offsets into key material (see below)
583 * Returns: A pointer to the new keyset.
585 * Use: Derives a new keyset from the given key material. The
586 * offsets @x@, @y@ and @z@ separate the key material into three
587 * parts. Between the @k@ and @k + x@ is `my' contribution to
588 * the key material; between @k + x@ and @k + y@ is `your'
589 * contribution; and between @k + y@ and @k + z@ is a shared
590 * value we made together. These are used to construct two
591 * pairs of symmetric keys. Each pair consists of an encryption
592 * key and a message authentication key. One pair is used for
593 * outgoing messages, the other for incoming messages.
595 * The new key is marked so that it won't be selected for output
596 * by @ksl_encrypt@. You can still encrypt data with it by
597 * calling @ks_encrypt@ directly.
600 extern keyset *ks_gen(const void */*k*/,
601 size_t /*x*/, size_t /*y*/, size_t /*z*/);
603 /* --- @ks_tregen@ --- *
605 * Arguments: @keyset *ks@ = pointer to a keyset
607 * Returns: The time at which moves ought to be made to replace this key.
610 extern time_t ks_tregen(keyset */*ks*/);
612 /* --- @ks_activate@ --- *
614 * Arguments: @keyset *ks@ = pointer to a keyset
618 * Use: Activates a keyset, so that it can be used for encrypting
622 extern void ks_activate(keyset */*ks*/);
624 /* --- @ks_encrypt@ --- *
626 * Arguments: @keyset *ks@ = pointer to a keyset
627 * @buf *b@ = pointer to input buffer
628 * @buf *bb@ = pointer to output buffer
630 * Returns: Zero if OK, nonzero if the key needs replacing. If the
631 * encryption failed, the output buffer is broken and zero is
634 * Use: Encrypts a block of data using the key. Note that the `key
635 * ought to be replaced' notification is only ever given once
636 * for each key. Also note that this call forces a keyset to be
637 * used even if it's marked as not for data output.
640 extern int ks_encrypt(keyset */*ks*/, buf */*b*/, buf */*bb*/);
642 /* --- @ks_decrypt@ --- *
644 * Arguments: @keyset *ks@ = pointer to a keyset
645 * @buf *b@ = pointer to an input buffer
646 * @buf *bb@ = pointer to an output buffer
648 * Returns: Zero on success, or nonzero if there was some problem.
650 * Use: Attempts to decrypt a message using a given key. Note that
651 * requesting decryption with a key directly won't clear a
652 * marking that it's not for encryption.
655 extern int ks_decrypt(keyset */*ks*/, buf */*b*/, buf */*bb*/);
657 /* --- @ksl_free@ --- *
659 * Arguments: @keyset **ksroot@ = pointer to keyset list head
663 * Use: Frees (releases references to) all of the keys in a keyset.
666 extern void ksl_free(keyset **/*ksroot*/);
668 /* --- @ksl_link@ --- *
670 * Arguments: @keyset **ksroot@ = pointer to keyset list head
671 * @keyset *ks@ = pointer to a keyset
675 * Use: Links a keyset into a list. A keyset can only be on one list
676 * at a time. Bad things happen otherwise.
679 extern void ksl_link(keyset **/*ksroot*/, keyset */*ks*/);
681 /* --- @ksl_prune@ --- *
683 * Arguments: @keyset **ksroot@ = pointer to keyset list head
687 * Use: Prunes the keyset list by removing keys which mustn't be used
691 extern void ksl_prune(keyset **/*ksroot*/);
693 /* --- @ksl_encrypt@ --- *
695 * Arguments: @keyset **ksroot@ = pointer to keyset list head
696 * @buf *b@ = pointer to input buffer
697 * @buf *bb@ = pointer to output buffer
699 * Returns: Nonzero if a new key is needed.
701 * Use: Encrypts a packet.
704 extern int ksl_encrypt(keyset **/*ksroot*/, buf */*b*/, buf */*bb*/);
706 /* --- @ksl_decrypt@ --- *
708 * Arguments: @keyset **ksroot@ = pointer to keyset list head
709 * @buf *b@ = pointer to input buffer
710 * @buf *bb@ = pointer to output buffer
712 * Returns: Nonzero if the packet couldn't be decrypted.
714 * Use: Decrypts a packet.
717 extern int ksl_decrypt(keyset **/*ksroot*/, buf */*b*/, buf */*bb*/);
719 /*----- Administration interface ------------------------------------------*/
721 /* --- @a_warn@ --- *
723 * Arguments: @const char *fmt@ = pointer to format string
724 * @...@ = other arguments
728 * Use: Informs all admin connections of a warning.
731 extern void a_warn(const char */*fmt*/, ...);
733 /* --- @a_create@ --- *
735 * Arguments: @int fd_in, fd_out@ = file descriptors to use
739 * Use: Creates a new admin connection.
742 extern void a_create(int /*fd_in*/, int /*fd_out*/);
744 /* --- @a_quit@ --- *
750 * Use: Shuts things down nicely.
753 extern void a_quit(void);
755 /* --- @a_daemon@ --- *
761 * Use: Informs the admin module that it's a daemon.
764 extern void a_daemon(void);
766 /* --- @a_init@ --- *
768 * Arguments: @const char *sock@ = socket name to create
772 * Use: Creates the admin listening socket.
775 extern void a_init(const char */*sock*/);
777 /*----- Peer management ---------------------------------------------------*/
779 /* --- @p_txstart@ --- *
781 * Arguments: @peer *p@ = pointer to peer block
782 * @unsigned msg@ = message type code
784 * Returns: A pointer to a buffer to write to.
786 * Use: Starts sending to a peer. Only one send can happen at a
790 extern buf *p_txstart(peer */*p*/, unsigned /*msg*/);
792 /* --- @p_txend@ --- *
794 * Arguments: @peer *p@ = pointer to peer block
798 * Use: Sends a packet to the peer.
801 extern void p_txend(peer */*p*/);
805 * Arguments: @peer *p@ = pointer to peer block
806 * @buf *b@ = buffer containing incoming packet
810 * Use: Handles a packet which needs to be sent to a peer.
813 extern void p_tun(peer */*p*/, buf */*b*/);
815 /* --- @p_interval@ --- *
821 * Use: Called periodically to do tidying.
824 extern void p_interval(void);
826 /* --- @p_stats@ --- *
828 * Arguments: @peer *p@ = pointer to a peer block
830 * Returns: A pointer to the peer's statistics.
833 extern stats *p_stats(peer */*p*/);
835 /* --- @p_ifname@ --- *
837 * Arguments: @peer *p@ = pointer to a peer block
839 * Returns: A pointer to the peer's interface name.
842 extern const char *p_ifname(peer */*p*/);
844 /* --- @p_addr@ --- *
846 * Arguments: @peer *p@ = pointer to a peer block
848 * Returns: A pointer to the peer's address.
851 extern const addr *p_addr(peer */*p*/);
853 /* --- @p_init@ --- *
855 * Arguments: @unsigned port@ = port number to listen to
859 * Use: Initializes the peer system; creates the socket.
862 extern void p_init(unsigned /*port*/);
864 /* --- @p_port@ --- *
868 * Returns: Port number used for socket.
871 unsigned p_port(void);
873 /* --- @p_create@ --- *
875 * Arguments: @const char *name@ = name for this peer
876 * @struct sockaddr *sa@ = socket address of peer
877 * @size_t sz@ = size of socket address
879 * Returns: Pointer to the peer block, or null if it failed.
881 * Use: Creates a new named peer block. No peer is actually attached
885 extern peer *p_create(const char */*name*/,
886 struct sockaddr */*sa*/, size_t /*sz*/);
888 /* --- @p_name@ --- *
890 * Arguments: @peer *p@ = pointer to a peer block
892 * Returns: A pointer to the peer's name.
895 extern const char *p_name(peer */*p*/);
897 /* --- @p_find@ --- *
899 * Arguments: @const char *name@ = name to look up
901 * Returns: Pointer to the peer block, or null if not found.
903 * Use: Finds a peer by name.
906 extern peer *p_find(const char */*name*/);
908 /* --- @p_destroy@ --- *
910 * Arguments: @peer *p@ = pointer to a peer
914 * Use: Destroys a peer.
917 extern void p_destroy(peer */*p*/);
919 /* --- @p_first@, @p_next@ --- *
921 * Arguments: @peer *p@ = a peer block
923 * Returns: @peer_first@ returns the first peer in some ordering;
924 * @peer_next@ returns the peer following a given one in the
925 * same ordering. Null is returned for the end of the list.
928 extern peer *p_first(void);
929 extern peer *p_next(peer */*p*/);
931 /*----- Tunnel interface --------------------------------------------------*/
933 /* --- @tun_init@ --- *
939 * Use: Initializes the tunneling system. Maybe this will require
940 * opening file descriptors or something.
943 extern void tun_init(void);
945 /* --- @tun_create@ --- *
947 * Arguments: @tunnel *t@ = pointer to tunnel block
948 * @peer *p@ = pointer to peer block
950 * Returns: Zero if it worked, nonzero on failure.
952 * Use: Initializes a new tunnel.
955 extern int tun_create(tunnel */*t*/, peer */*p*/);
957 /* --- @tun_ifname@ --- *
959 * Arguments: @tunnel *t@ = pointer to tunnel block
961 * Returns: A pointer to the tunnel's interface name.
964 extern const char *tun_ifname(tunnel */*t*/);
966 /* --- @tun_inject@ --- *
968 * Arguments: @tunnel *t@ = pointer to tunnel block
969 * @buf *b@ = buffer to send
973 * Use: Injects a packet into the local network stack.
976 extern void tun_inject(tunnel */*t*/, buf */*b*/);
978 /* --- @tun_destroy@ --- *
980 * Arguments: @tunnel *t@ = pointer to tunnel block
984 * Use: Destroys a tunnel.
987 extern void tun_destroy(tunnel */*t*/);
989 /*----- Other handy utilities ---------------------------------------------*/
993 * Arguments: @mp *m@ = a multiprecision integer
995 * Returns: A pointer to the integer's textual representation.
997 * Use: Converts a multiprecision integer to a string. Corrupts
1001 extern const char *mpstr(mp */*m*/);
1003 /* --- @timestr@ --- *
1005 * Arguments: @time_t t@ = a time to convert
1007 * Returns: A pointer to a textual representation of the time.
1009 * Use: Converts a time to a textual representation. Corrupts
1013 extern const char *timestr(time_t /*t*/);
1015 /*----- That's all, folks -------------------------------------------------*/