3 * $Id: tripe.h,v 1.16 2003/07/13 11:19:49 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 1.16 2003/07/13 11:19:49 mdw
33 * Incopatible protocol fix! Include message type code under MAC tag to prevent
34 * cut-and-paste from key-exchange messages to general packet transport.
36 * Revision 1.15 2003/05/16 12:09:03 mdw
37 * Allow binding to a chosen address.
39 * Revision 1.14 2003/04/06 10:36:33 mdw
40 * Rearrange so as not to include Linux headers unless we need to.
42 * Revision 1.13 2003/04/06 10:26:35 mdw
43 * Report peer name on decrypt errors.
45 * Revision 1.12 2003/04/06 10:25:17 mdw
46 * Support Linux TUN/TAP device. Fix some bugs.
48 * Revision 1.11 2002/01/13 14:57:42 mdw
51 * Revision 1.10 2002/01/13 14:54:58 mdw
54 * Revision 1.9 2001/06/22 19:40:36 mdw
55 * Support expiry of other peers' public keys.
57 * Revision 1.8 2001/06/19 22:10:57 mdw
58 * Some more constants for the algorithms. Document the packet format
59 * change for non-malleability. Moved @buf@ definitions to separate header
62 * Revision 1.7 2001/03/03 12:07:08 mdw
63 * Rename word get and put functions now that there's 16-bit support.
65 * Revision 1.6 2001/02/19 19:11:09 mdw
66 * Output buffering on admin connections.
68 * Revision 1.5 2001/02/16 21:41:43 mdw
69 * Major changes. See source files for details.
71 * Revision 1.4 2001/02/05 19:56:37 mdw
72 * Sequence number protection, and BSD tunnels.
74 * Revision 1.3 2001/02/04 01:17:55 mdw
75 * Create a configuration header file to tidy up command lines.
77 * Revision 1.2 2001/02/03 22:40:29 mdw
78 * Put timer information into the entropy pool when packets are received
79 * and on similar events. Reseed the generator on the interval timer.
81 * Revision 1.1 2001/02/03 20:26:37 mdw
93 /*----- Header files ------------------------------------------------------*/
108 #include <sys/types.h>
109 #include <sys/time.h>
112 #include <sys/stat.h>
114 #include <sys/socket.h>
116 #include <netinet/in.h>
117 #include <arpa/inet.h>
123 #include <mLib/alloc.h>
124 #include <mLib/arena.h>
125 #include <mLib/bres.h>
126 #include <mLib/dstr.h>
127 #include <mLib/env.h>
128 #include <mLib/fdflags.h>
129 #include <mLib/fwatch.h>
130 #include <mLib/mdwopt.h>
131 #include <mLib/quis.h>
132 #include <mLib/report.h>
133 #include <mLib/sel.h>
134 #include <mLib/selbuf.h>
135 #include <mLib/sig.h>
136 #include <mLib/str.h>
137 #include <mLib/sub.h>
138 #include <mLib/trace.h>
140 #include <catacomb/gcipher.h>
141 #include <catacomb/gmac.h>
142 #include <catacomb/grand.h>
143 #include <catacomb/key.h>
144 #include <catacomb/paranoia.h>
146 #include <catacomb/noise.h>
147 #include <catacomb/rand.h>
149 #include <catacomb/mp.h>
150 #include <catacomb/mpmont.h>
151 #include <catacomb/mprand.h>
152 #include <catacomb/dh.h>
159 /*----- Magic numbers -----------------------------------------------------*/
161 /* --- Tunnel types --- */
168 /* --- Trace flags --- */
176 #define T_KEYEXCH 64u
177 #define T_KEYMGMT 128u
183 #define SEC(n) (n##u)
184 #define MIN(n) (n##u * 60u)
185 #define MEG(n) (n##ul * 1024ul * 1024ul)
187 /* --- Other things --- */
189 #define PKBUFSZ 65536
191 /*----- TrIPE protocol ----------------------------------------------------*/
193 /* --- TrIPE message format --- *
195 * A packet begins with a single-byte message type. The top four bits are a
196 * category code used to send the message to the right general place in the
197 * code; the bottom bits identify the actual message type.
200 #define MSG_CATMASK 0xf0
201 #define MSG_TYPEMASK 0x0f
203 /* --- Encrypted message packets --- *
205 * Messages of category @MSG_PACKET@ contain encrypted network packets. The
206 * message content is a symmetric-encrypted block (see below). Reception of
207 * a packet encrypted under a new key implicitly permits that key to be used
208 * to send further packets.
210 * The only packet type accepted is zero.
212 * Packets may be encrypted under any live keyset, but should use the most
216 #define MSG_PACKET 0x00
218 /* --- Key exchange packets --- */
220 #define MSG_KEYEXCH 0x10
222 #define KX_PRECHAL 0u
227 #define KX_SWITCHOK 5u
230 /* --- Symmetric encryption and keysets --- *
232 * Packets consist of an 80-bit MAC, a 32-bit sequence number, and the
235 * The plaintext is encrypted using Blowfish in CBC mode with ciphertext
236 * stealing (as described in [Schneier]. The initialization vector is
237 * selected randomly, and prepended to the actual ciphertext.
239 * The MAC is computed using the HMAC construction with RIPEMD160 over the
240 * sequence number and the ciphertext (with IV); the first 80 bits of the
241 * output are used. (This is the minimum allowed by the draft FIPS for HMAC,
242 * and the recommended truncation.)
244 * A keyset consists of
246 * * an integrity (MAC) key;
247 * * a confidentiality (encryption) key; and
248 * * a sequence numbering space
250 * in each direction. The packets sent by a host encrypted under a
251 * particular keyset are assigned consecutive sequence numbers starting from
252 * zero. The receiving host must ensure that it only accepts each packet at
253 * most once. It should maintain a window of sequence numbers: packets with
254 * numbers beyond the end of the window are accepted and cause the window to
255 * be advanced; packets with numbers before the start of the window are
256 * rejected; packets with numbers which appear within the window are accepted
257 * only if the number has not been seen before.
259 * When a host sends a @KX_SWITCH@ or @KX_SWITCHOK@ message, it installs the
260 * newly-negotiated keyset in a `listen-only' state: it may not send a packet
261 * encrypted under the keyset until either it has received a @KX_SWITCH@ or
262 * @KX_SWITCHOK@ message, or a @MSG_PACKET@ encrypted under the keyset, from
266 /*----- Cipher selections -------------------------------------------------*/
268 #include <catacomb/blowfish.h>
269 #include <catacomb/blowfish-cbc.h>
270 #include <catacomb/blowfish-counter.h>
271 #include <catacomb/rmd160.h>
272 #include <catacomb/rmd160-hmac.h>
274 #define CIPHER (&blowfish_cbc)
275 #define MAC (&rmd160_hmac)
277 #define HASH_CTX rmd160_ctx
278 #define HASH_INIT rmd160_init
279 #define HASH rmd160_hash
280 #define HASH_STRING(c, s) HASH((c), s, sizeof(s))
281 #define HASH_DONE rmd160_done
282 #define HASHSZ RMD160_HASHSZ
284 #define MGF_CTX blowfish_counterctx
285 #define MGF_INIT blowfish_counterinit
286 #define MGF_CRYPT blowfish_counterencrypt
289 #define IVSZ BLOWFISH_BLKSZ
292 /*----- Data structures ---------------------------------------------------*/
294 /* --- Socket addresses --- *
296 * A magic union of supported socket addresses.
301 struct sockaddr_in sin;
304 /* --- A symmetric keyset --- *
306 * A keyset contains a set of symmetric keys for encrypting and decrypting
307 * packets. Keysets are stored in a list, sorted in reverse order of
308 * creation, so that the most recent keyset (the one most likely to be used)
311 * Each keyset has a time limit and a data limit. The keyset is destroyed
312 * when either it has existed for too long, or it has been used to encrypt
313 * too much data. New key exchanges are triggered when keys are close to
317 typedef struct keyset {
318 struct keyset *next; /* Next active keyset in the list */
319 unsigned ref; /* Reference count for keyset */
320 struct peer *p; /* Pointer to peer structure */
321 time_t t_exp; /* Expiry time for this keyset */
322 unsigned long sz_exp; /* Data limit for the keyset */
323 T( unsigned seq; ) /* Sequence number for tracing */
324 unsigned f; /* Various useful flags */
325 gcipher *cin, *cout; /* Keyset ciphers for encryption */
326 gmac *min, *mout; /* Keyset MACs for integrity */
327 uint32 oseq; /* Outbound sequence number */
328 uint32 iseq, iwin; /* Inbound sequence number */
331 #define KS_SEQWINSZ 32 /* Bits in sequence number window */
333 #define KSF_LISTEN 1u /* Don't encrypt packets yet */
334 #define KSF_LINK 2u /* Key is in a linked list */
336 /* --- Key exchange --- *
338 * TrIPE uses the Wrestlers Protocol for its key exchange. The Wrestlers
339 * Protocol has a number of desirable features (e.g., perfect forward
340 * secrecy, and zero-knowledge authentication) which make it attractive for
341 * use in TrIPE. The Wrestlers Protocol was designed by Mark Wooding and
348 typedef struct kxchal {
349 struct keyexch *kx; /* Pointer back to key exchange */
350 mp *c; /* Responder's challenge */
351 mp *r; /* My reply to the challenge */
352 keyset *ks; /* Pointer to temporary keyset */
353 unsigned f; /* Various useful flags */
354 sel_timer t; /* Response timer for challenge */
355 octet hc[HASHSZ]; /* Hash of his challenge */
356 mp *ck; /* The check value */
357 octet hswrq_in[HASHSZ]; /* Inbound switch request message */
358 octet hswok_in[HASHSZ]; /* Inbound switch confirmation */
359 octet hswrq_out[HASHSZ]; /* Outbound switch request message */
360 octet hswok_out[HASHSZ]; /* Outbound switch confirmation */
363 typedef struct keyexch {
364 struct peer *p; /* Pointer back to the peer */
365 keyset **ks; /* Peer's list of keysets */
366 unsigned f; /* Various useful flags */
367 unsigned s; /* Current state in exchange */
368 sel_timer t; /* Timer for next exchange */
369 dh_pub kpub; /* Peer's public key */
370 time_t texp_kpub; /* Expiry time for public key */
371 mp *alpha; /* My temporary secret */
372 mp *c; /* My challenge */
373 mp *rx; /* The expected response */
374 unsigned nr; /* Number of extant responses */
375 time_t t_valid; /* When this exchange goes bad */
376 octet hc[HASHSZ]; /* Hash of my challenge */
377 kxchal *r[KX_NCHAL]; /* Array of challenges */
380 #define KXF_TIMER 1u /* Waiting for a timer to go off */
381 #define KXF_DEAD 2u /* The key-exchanger isn't up */
382 #define KXF_PUBKEY 4u /* Key exchanger has a public key */
385 KXS_DEAD, /* Uninitialized state (magical) */
386 KXS_CHAL, /* Main answer-challenges state */
387 KXS_COMMIT, /* Committed: send switch request */
388 KXS_SWITCH /* Switched: send confirmation */
391 /* --- Tunnel structure --- *
393 * Used to maintain system-specific information about the tunnel interface.
396 #if TUN_TYPE == TUN_LINUX
397 # include <linux/if.h>
398 # include <linux/if_tun.h>
401 typedef struct tunnel {
402 #if TUN_TYPE == TUN_UNET
403 sel_file f; /* Selector for Usernet device */
404 struct peer *p; /* Pointer to my peer */
405 #elif TUN_TYPE == TUN_LINUX
406 sel_file f; /* Selector for TUN/TAP device */
407 struct peer *p; /* Pointer to my peer */
408 char ifn[IFNAMSIZ]; /* Interface name buffer */
409 #elif TUN_TYPE == TUN_BSD
410 sel_file f; /* Selector for tunnel device */
411 struct peer *p; /* Pointer to my peer */
412 unsigned n; /* Number of my tunnel device */
414 # error "No support for this tunnel type"
418 /* --- Peer statistics --- *
420 * Contains various interesting and not-so-interesting statistics about a
421 * peer. This is updated by various parts of the code. The format of the
422 * structure isn't considered private, and @p_stats@ returns a pointer to the
423 * statistics block for a given peer.
426 typedef struct stats {
427 unsigned long sz_in, sz_out; /* Size of all data in and out */
428 unsigned long sz_kxin, sz_kxout; /* Size of key exchange messages */
429 unsigned long sz_ipin, sz_ipout; /* Size of encapsulated IP packets */
430 time_t t_start, t_last; /* Time peer created, last recv */
431 unsigned long n_reject; /* Number of rejected packets */
432 unsigned long n_in, n_out; /* Number of packets in and out */
433 unsigned long n_kxin, n_kxout; /* Number of key exchange packets */
434 unsigned long n_ipin, n_ipout; /* Number of encrypted packets */
437 /* --- Peer structure --- *
439 * The main structure which glues everything else together.
442 typedef struct peer {
443 struct peer *next, *prev; /* Links to next and previous */
444 char *name; /* Name of this peer */
445 tunnel t; /* Tunnel for local packets */
446 keyset *ks; /* List head for keysets */
447 buf b; /* Buffer for sending packets */
448 addr peer; /* Peer socket address */
449 size_t sasz; /* Socket address size */
450 stats st; /* Statistics */
451 keyexch kx; /* Key exchange protocol block */
454 /* --- Admin structure --- */
456 #define OBUFSZ 16384u
458 typedef struct obuf {
459 struct obuf *next; /* Next buffer in list */
460 char *p_in, *p_out; /* Pointers into the buffer */
461 char buf[OBUFSZ]; /* The actual buffer */
464 typedef struct admin {
465 struct admin *next, *prev; /* Links to next and previous */
466 unsigned f; /* Various useful flags */
468 unsigned seq; /* Sequence number for tracing */
470 char *pname; /* Peer name to create */
471 char *paddr; /* Address string to resolve */
472 obuf *o_head, *o_tail; /* Output buffer list */
473 selbuf b; /* Line buffer for commands */
474 sel_file w; /* Selector for write buffering */
475 bres_client r; /* Background resolver task */
476 sel_timer t; /* Timer for resolver */
477 addr peer; /* Address to set */
478 size_t sasz; /* Size of the address */
481 #define AF_DEAD 1u /* Destroy this admin block */
482 #define AF_LOCK 2u /* Don't destroy it yet */
484 /*----- Global variables --------------------------------------------------*/
486 extern sel_state sel; /* Global I/O event state */
487 extern dh_priv kpriv; /* Our private key */
488 extern mpmont mg; /* Montgomery context for DH group */
489 extern octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ];
492 extern const trace_opt tr_opts[]; /* Trace options array */
493 extern unsigned tr_flags; /* Trace options flags */
496 /*----- Other macros ------------------------------------------------------*/
498 #define TIMER noise_timer(RAND_GLOBAL)
500 /*----- Key management ----------------------------------------------------*/
502 /* --- @km_interval@ --- *
506 * Returns: Zero if OK, nonzero to force reloading of keys.
508 * Use: Called on the interval timer to perform various useful jobs.
511 extern int km_interval(void);
513 /* --- @km_init@ --- *
515 * Arguments: @const char *kr_priv@ = private keyring file
516 * @const char *kr_pub@ = public keyring file
517 * @const char *tag@ = tag to load
521 * Use: Initializes, and loads the private key.
524 extern void km_init(const char */*kr_priv*/, const char */*kr_pub*/,
525 const char */*tag*/);
527 /* --- @km_getpubkey@ --- *
529 * Arguments: @const char *tag@ = public key tag to load
530 * @dh_pub *kpub@ = where to put the public key
531 * @time_t *t_exp@ = where to put the expiry time
533 * Returns: Zero if OK, nonzero if it failed.
535 * Use: Fetches a public key from the keyring.
538 extern int km_getpubkey(const char */*tag*/, dh_pub */*kpub*/,
541 /*----- Key exchange ------------------------------------------------------*/
543 /* --- @kx_start@ --- *
545 * Arguments: @keyexch *kx@ = pointer to key exchange context
549 * Use: Stimulates a key exchange. If a key exchage is in progress,
550 * a new challenge is sent (unless the quiet timer forbids
551 * this); if no exchange is in progress, one is commenced.
554 extern void kx_start(keyexch */*kx*/);
556 /* --- @kx_message@ --- *
558 * Arguments: @keyexch *kx@ = pointer to key exchange context
559 * @unsigned msg@ = the message code
560 * @buf *b@ = pointer to buffer containing the packet
564 * Use: Reads a packet containing key exchange messages and handles
568 extern void kx_message(keyexch */*kx*/, unsigned /*msg*/, buf */*b*/);
570 /* --- @kx_free@ --- *
572 * Arguments: @keyexch *kx@ = pointer to key exchange context
576 * Use: Frees everything in a key exchange context.
579 extern void kx_free(keyexch */*kx*/);
581 /* --- @kx_newkeys@ --- *
583 * Arguments: @keyexch *kx@ = pointer to key exchange context
587 * Use: Informs the key exchange module that its keys may have
588 * changed. If fetching the new keys fails, the peer will be
589 * destroyed, we log messages and struggle along with the old
593 extern void kx_newkeys(keyexch */*kx*/);
595 /* --- @kx_init@ --- *
597 * Arguments: @keyexch *kx@ = pointer to key exchange context
598 * @peer *p@ = pointer to peer context
599 * @keyset **ks@ = pointer to keyset list
601 * Returns: Zero if OK, nonzero if it failed.
603 * Use: Initializes a key exchange module. The module currently
604 * contains no keys, and will attempt to initiate a key
608 extern int kx_init(keyexch */*kx*/, peer */*p*/, keyset **/*ks*/);
610 /*----- Keysets and symmetric cryptography --------------------------------*/
612 /* --- @ks_drop@ --- *
614 * Arguments: @keyset *ks@ = pointer to a keyset
618 * Use: Decrements a keyset's reference counter. If the counter hits
619 * zero, the keyset is freed.
622 extern void ks_drop(keyset */*ks*/);
624 /* --- @ks_gen@ --- *
626 * Arguments: @const void *k@ = pointer to key material
627 * @size_t x, y, z@ = offsets into key material (see below)
628 * @peer *p@ = pointer to peer information
630 * Returns: A pointer to the new keyset.
632 * Use: Derives a new keyset from the given key material. The
633 * offsets @x@, @y@ and @z@ separate the key material into three
634 * parts. Between the @k@ and @k + x@ is `my' contribution to
635 * the key material; between @k + x@ and @k + y@ is `your'
636 * contribution; and between @k + y@ and @k + z@ is a shared
637 * value we made together. These are used to construct two
638 * pairs of symmetric keys. Each pair consists of an encryption
639 * key and a message authentication key. One pair is used for
640 * outgoing messages, the other for incoming messages.
642 * The new key is marked so that it won't be selected for output
643 * by @ksl_encrypt@. You can still encrypt data with it by
644 * calling @ks_encrypt@ directly.
647 extern keyset *ks_gen(const void */*k*/,
648 size_t /*x*/, size_t /*y*/, size_t /*z*/,
651 /* --- @ks_tregen@ --- *
653 * Arguments: @keyset *ks@ = pointer to a keyset
655 * Returns: The time at which moves ought to be made to replace this key.
658 extern time_t ks_tregen(keyset */*ks*/);
660 /* --- @ks_activate@ --- *
662 * Arguments: @keyset *ks@ = pointer to a keyset
666 * Use: Activates a keyset, so that it can be used for encrypting
670 extern void ks_activate(keyset */*ks*/);
672 /* --- @ks_encrypt@ --- *
674 * Arguments: @keyset *ks@ = pointer to a keyset
675 * @unsigned ty@ = message type
676 * @buf *b@ = pointer to input buffer
677 * @buf *bb@ = pointer to output buffer
679 * Returns: Zero if OK, nonzero if the key needs replacing. If the
680 * encryption failed, the output buffer is broken and zero is
683 * Use: Encrypts a block of data using the key. Note that the `key
684 * ought to be replaced' notification is only ever given once
685 * for each key. Also note that this call forces a keyset to be
686 * used even if it's marked as not for data output.
689 extern int ks_encrypt(keyset */*ks*/, unsigned /*ty*/,
690 buf */*b*/, buf */*bb*/);
692 /* --- @ks_decrypt@ --- *
694 * Arguments: @keyset *ks@ = pointer to a keyset
695 * @unsigned ty@ = expected type code
696 * @buf *b@ = pointer to an input buffer
697 * @buf *bb@ = pointer to an output buffer
699 * Returns: Zero on success, or nonzero if there was some problem.
701 * Use: Attempts to decrypt a message using a given key. Note that
702 * requesting decryption with a key directly won't clear a
703 * marking that it's not for encryption.
706 extern int ks_decrypt(keyset */*ks*/, unsigned /*ty*/,
707 buf */*b*/, buf */*bb*/);
709 /* --- @ksl_free@ --- *
711 * Arguments: @keyset **ksroot@ = pointer to keyset list head
715 * Use: Frees (releases references to) all of the keys in a keyset.
718 extern void ksl_free(keyset **/*ksroot*/);
720 /* --- @ksl_link@ --- *
722 * Arguments: @keyset **ksroot@ = pointer to keyset list head
723 * @keyset *ks@ = pointer to a keyset
727 * Use: Links a keyset into a list. A keyset can only be on one list
728 * at a time. Bad things happen otherwise.
731 extern void ksl_link(keyset **/*ksroot*/, keyset */*ks*/);
733 /* --- @ksl_prune@ --- *
735 * Arguments: @keyset **ksroot@ = pointer to keyset list head
739 * Use: Prunes the keyset list by removing keys which mustn't be used
743 extern void ksl_prune(keyset **/*ksroot*/);
745 /* --- @ksl_encrypt@ --- *
747 * Arguments: @keyset **ksroot@ = pointer to keyset list head
748 * @unsigned ty@ = message type
749 * @buf *b@ = pointer to input buffer
750 * @buf *bb@ = pointer to output buffer
752 * Returns: Nonzero if a new key is needed.
754 * Use: Encrypts a packet.
757 extern int ksl_encrypt(keyset **/*ksroot*/, unsigned /*ty*/,
758 buf */*b*/, buf */*bb*/);
760 /* --- @ksl_decrypt@ --- *
762 * Arguments: @keyset **ksroot@ = pointer to keyset list head
763 * @unsigned ty@ = expected type code
764 * @buf *b@ = pointer to input buffer
765 * @buf *bb@ = pointer to output buffer
767 * Returns: Nonzero if the packet couldn't be decrypted.
769 * Use: Decrypts a packet.
772 extern int ksl_decrypt(keyset **/*ksroot*/, unsigned /*ty*/,
773 buf */*b*/, buf */*bb*/);
775 /*----- Administration interface ------------------------------------------*/
777 /* --- @a_warn@ --- *
779 * Arguments: @const char *fmt@ = pointer to format string
780 * @...@ = other arguments
784 * Use: Informs all admin connections of a warning.
787 extern void a_warn(const char */*fmt*/, ...);
789 /* --- @a_create@ --- *
791 * Arguments: @int fd_in, fd_out@ = file descriptors to use
795 * Use: Creates a new admin connection.
798 extern void a_create(int /*fd_in*/, int /*fd_out*/);
800 /* --- @a_quit@ --- *
806 * Use: Shuts things down nicely.
809 extern void a_quit(void);
811 /* --- @a_daemon@ --- *
817 * Use: Informs the admin module that it's a daemon.
820 extern void a_daemon(void);
822 /* --- @a_init@ --- *
824 * Arguments: @const char *sock@ = socket name to create
828 * Use: Creates the admin listening socket.
831 extern void a_init(const char */*sock*/);
833 /*----- Peer management ---------------------------------------------------*/
835 /* --- @p_txstart@ --- *
837 * Arguments: @peer *p@ = pointer to peer block
838 * @unsigned msg@ = message type code
840 * Returns: A pointer to a buffer to write to.
842 * Use: Starts sending to a peer. Only one send can happen at a
846 extern buf *p_txstart(peer */*p*/, unsigned /*msg*/);
848 /* --- @p_txend@ --- *
850 * Arguments: @peer *p@ = pointer to peer block
854 * Use: Sends a packet to the peer.
857 extern void p_txend(peer */*p*/);
861 * Arguments: @peer *p@ = pointer to peer block
862 * @buf *b@ = buffer containing incoming packet
866 * Use: Handles a packet which needs to be sent to a peer.
869 extern void p_tun(peer */*p*/, buf */*b*/);
871 /* --- @p_interval@ --- *
877 * Use: Called periodically to do tidying.
880 extern void p_interval(void);
882 /* --- @p_stats@ --- *
884 * Arguments: @peer *p@ = pointer to a peer block
886 * Returns: A pointer to the peer's statistics.
889 extern stats *p_stats(peer */*p*/);
891 /* --- @p_ifname@ --- *
893 * Arguments: @peer *p@ = pointer to a peer block
895 * Returns: A pointer to the peer's interface name.
898 extern const char *p_ifname(peer */*p*/);
900 /* --- @p_addr@ --- *
902 * Arguments: @peer *p@ = pointer to a peer block
904 * Returns: A pointer to the peer's address.
907 extern const addr *p_addr(peer */*p*/);
909 /* --- @p_init@ --- *
911 * Arguments: @struct in_addr addr@ = address to bind to
912 * @unsigned port@ = port number to listen to
916 * Use: Initializes the peer system; creates the socket.
919 extern void p_init(struct in_addr /*addr*/, unsigned /*port*/);
921 /* --- @p_port@ --- *
925 * Returns: Port number used for socket.
928 unsigned p_port(void);
930 /* --- @p_create@ --- *
932 * Arguments: @const char *name@ = name for this peer
933 * @struct sockaddr *sa@ = socket address of peer
934 * @size_t sz@ = size of socket address
936 * Returns: Pointer to the peer block, or null if it failed.
938 * Use: Creates a new named peer block. No peer is actually attached
942 extern peer *p_create(const char */*name*/,
943 struct sockaddr */*sa*/, size_t /*sz*/);
945 /* --- @p_name@ --- *
947 * Arguments: @peer *p@ = pointer to a peer block
949 * Returns: A pointer to the peer's name.
952 extern const char *p_name(peer */*p*/);
954 /* --- @p_find@ --- *
956 * Arguments: @const char *name@ = name to look up
958 * Returns: Pointer to the peer block, or null if not found.
960 * Use: Finds a peer by name.
963 extern peer *p_find(const char */*name*/);
965 /* --- @p_destroy@ --- *
967 * Arguments: @peer *p@ = pointer to a peer
971 * Use: Destroys a peer.
974 extern void p_destroy(peer */*p*/);
976 /* --- @p_first@, @p_next@ --- *
978 * Arguments: @peer *p@ = a peer block
980 * Returns: @peer_first@ returns the first peer in some ordering;
981 * @peer_next@ returns the peer following a given one in the
982 * same ordering. Null is returned for the end of the list.
985 extern peer *p_first(void);
986 extern peer *p_next(peer */*p*/);
988 /*----- Tunnel interface --------------------------------------------------*/
990 /* --- @tun_init@ --- *
996 * Use: Initializes the tunneling system. Maybe this will require
997 * opening file descriptors or something.
1000 extern void tun_init(void);
1002 /* --- @tun_create@ --- *
1004 * Arguments: @tunnel *t@ = pointer to tunnel block
1005 * @peer *p@ = pointer to peer block
1007 * Returns: Zero if it worked, nonzero on failure.
1009 * Use: Initializes a new tunnel.
1012 extern int tun_create(tunnel */*t*/, peer */*p*/);
1014 /* --- @tun_ifname@ --- *
1016 * Arguments: @tunnel *t@ = pointer to tunnel block
1018 * Returns: A pointer to the tunnel's interface name.
1021 extern const char *tun_ifname(tunnel */*t*/);
1023 /* --- @tun_inject@ --- *
1025 * Arguments: @tunnel *t@ = pointer to tunnel block
1026 * @buf *b@ = buffer to send
1030 * Use: Injects a packet into the local network stack.
1033 extern void tun_inject(tunnel */*t*/, buf */*b*/);
1035 /* --- @tun_destroy@ --- *
1037 * Arguments: @tunnel *t@ = pointer to tunnel block
1041 * Use: Destroys a tunnel.
1044 extern void tun_destroy(tunnel */*t*/);
1046 /*----- Other handy utilities ---------------------------------------------*/
1048 /* --- @mpstr@ --- *
1050 * Arguments: @mp *m@ = a multiprecision integer
1052 * Returns: A pointer to the integer's textual representation.
1054 * Use: Converts a multiprecision integer to a string. Corrupts
1058 extern const char *mpstr(mp */*m*/);
1060 /* --- @timestr@ --- *
1062 * Arguments: @time_t t@ = a time to convert
1064 * Returns: A pointer to a textual representation of the time.
1066 * Use: Converts a time to a textual representation. Corrupts
1070 extern const char *timestr(time_t /*t*/);
1072 /*----- That's all, folks -------------------------------------------------*/