2 * ccp.c - PPP Compression Control Protocol.
4 * Copyright (c) 1994 The Australian National University.
7 * Permission to use, copy, modify, and distribute this software and its
8 * documentation is hereby granted, provided that the above copyright
9 * notice appears in all copies. This software is provided without any
10 * warranty, express or implied. The Australian National University
11 * makes no representations about the suitability of this software for
14 * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
15 * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
16 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
17 * THE AUSTRALIAN NATIONAL UNIVERSITY HAVE BEEN ADVISED OF THE POSSIBILITY
20 * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
21 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
22 * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
23 * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
24 * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
29 static char rcsid[] = "$Id: ccp.c,v 1.4 1994/09/16 02:14:31 paulus Exp $";
33 #include <sys/ioctl.h>
41 ccp_options ccp_wantoptions[NPPP]; /* what to request the peer to use */
42 ccp_options ccp_gotoptions[NPPP]; /* what the peer agreed to do */
43 ccp_options ccp_allowoptions[NPPP]; /* what we'll agree to do */
44 ccp_options ccp_hisoptions[NPPP]; /* what we agreed to do */
47 * Callbacks for fsm code.
49 static void ccp_resetci __ARGS((fsm *));
50 static int ccp_cilen __ARGS((fsm *));
51 static void ccp_addci __ARGS((fsm *, u_char *, int *));
52 static int ccp_ackci __ARGS((fsm *, u_char *, int));
53 static int ccp_nakci __ARGS((fsm *, u_char *, int));
54 static int ccp_rejci __ARGS((fsm *, u_char *, int));
55 static int ccp_reqci __ARGS((fsm *, u_char *, int *, int));
56 static void ccp_up __ARGS((fsm *));
57 static void ccp_down __ARGS((fsm *));
58 static int ccp_extcode __ARGS((fsm *, int, int, u_char *, int));
59 static void ccp_rack_timeout __ARGS(());
61 static fsm_callbacks ccp_callbacks = {
80 * Length of configuration options, which describe possible
81 * compression methods.
86 * Configuration option values for compression methods.
88 #define CI_BSD_COMPRESS 0x21
91 * Information relating to BSD Compress configuration options.
93 #define BSD_NBITS(x) ((x) & 0x1F)
94 #define BSD_VERSION(x) ((x) >> 5)
95 #define BSD_CURRENT_VERSION 1
96 #define BSD_MAKE_OPT(v, n) (((v) << 5) | (n))
99 * Do we want / did we get any compression?
101 #define ANY_COMPRESS(opt) ((opt).bsd_compress)
104 * Local state (mainly for handling reset-reqs and reset-acks
106 static int ccp_localstate[NPPP];
107 #define RACK_PENDING 1 /* waiting for reset-ack */
108 #define RREQ_REPEAT 2 /* send another reset-req if no reset-ack */
110 #define RACKTIMEOUT 1 /* second */
113 * ccp_init - initialize CCP.
119 fsm *f = &ccp_fsm[unit];
123 f->callbacks = &ccp_callbacks;
126 memset(&ccp_wantoptions[unit], 0, sizeof(ccp_options));
127 memset(&ccp_gotoptions[unit], 0, sizeof(ccp_options));
128 memset(&ccp_allowoptions[unit], 0, sizeof(ccp_options));
129 memset(&ccp_hisoptions[unit], 0, sizeof(ccp_options));
131 ccp_wantoptions[0].bsd_bits = 12; /* default value */
133 ccp_allowoptions[0].bsd_compress = 1;
134 ccp_allowoptions[0].bsd_bits = MAX_BSD_BITS;
138 * ccp_open - CCP is allowed to come up.
144 fsm *f = &ccp_fsm[unit];
146 if (f->state != OPENED)
147 ccp_flags_set(unit, 1, 0);
148 if (!ANY_COMPRESS(ccp_wantoptions[unit]))
149 f->flags |= OPT_SILENT;
154 * ccp_close - Terminate CCP.
160 ccp_flags_set(unit, 0, 0);
161 fsm_close(&ccp_fsm[unit]);
165 * ccp_lowerup - we may now transmit CCP packets.
171 fsm_lowerup(&ccp_fsm[unit]);
175 * ccp_lowerdown - we may not transmit CCP packets.
181 fsm_lowerdown(&ccp_fsm[unit]);
185 * ccp_input - process a received CCP packet.
188 ccp_input(unit, p, len)
193 fsm *f = &ccp_fsm[unit];
197 * Check for a terminate-request so we can print a message.
200 fsm_input(f, p, len);
201 if (oldstate == OPENED && p[0] == TERMREQ && f->state != OPENED)
202 syslog(LOG_NOTICE, "Compression disabled by peer.");
206 * Handle a CCP-specific code.
209 ccp_extcode(f, code, id, p, len)
217 if (f->state != OPENED)
219 /* send a reset-ack, which the transmitter will see and
220 reset its compression state. */
221 fsm_sdata(f, RESETACK, id, NULL, 0);
225 if (ccp_localstate[f->unit] & RACK_PENDING && id == f->reqid) {
226 ccp_localstate[f->unit] &= ~(RACK_PENDING | RREQ_REPEAT);
227 UNTIMEOUT(ccp_rack_timeout, (caddr_t) f);
239 * ccp_protrej - peer doesn't talk CCP.
245 ccp_flags_set(unit, 0, 0);
246 fsm_lowerdown(&ccp_fsm[unit]);
250 * ccp_resetci - initialize at start of negotiation.
256 ccp_options *go = &ccp_gotoptions[f->unit];
259 *go = ccp_wantoptions[f->unit];
260 if (go->bsd_compress) {
261 opt_buf[0] = CI_BSD_COMPRESS;
262 opt_buf[1] = CILEN_BSD;
263 opt_buf[2] = BSD_MAKE_OPT(BSD_CURRENT_VERSION, go->bsd_bits);
264 if (!ccp_test(f->unit, opt_buf, CILEN_BSD, 0))
265 go->bsd_compress = 0;
270 * ccp_cilen - Return total length of our configuration info.
276 ccp_options *go = &ccp_gotoptions[f->unit];
278 return (go->bsd_compress? CILEN_BSD: 0);
282 * ccp_addci - put our requests in a packet.
285 ccp_addci(f, p, lenp)
290 ccp_options *go = &ccp_gotoptions[f->unit];
293 if (go->bsd_compress) {
294 p[0] = CI_BSD_COMPRESS;
296 p[2] = BSD_MAKE_OPT(BSD_CURRENT_VERSION, go->bsd_bits);
297 if (ccp_test(f->unit, p, CILEN_BSD, 0))
300 go->bsd_compress = 0;
306 * ccp_ackci - process a received configure-ack, and return
307 * 1 iff the packet was OK.
315 ccp_options *go = &ccp_gotoptions[f->unit];
317 if (go->bsd_compress) {
318 if (len < CILEN_BSD || p[0] != CI_BSD_COMPRESS || p[1] != CILEN_BSD
319 || p[2] != BSD_MAKE_OPT(BSD_CURRENT_VERSION, go->bsd_bits))
330 * ccp_nakci - process received configure-nak.
331 * Returns 1 iff the nak was OK.
339 ccp_options *go = &ccp_gotoptions[f->unit];
340 ccp_options no; /* options we've seen already */
341 ccp_options try; /* options to ask for next time */
343 memset(&no, 0, sizeof(no));
346 if (go->bsd_compress && !no.bsd_compress && len >= CILEN_BSD
347 && p[0] == CI_BSD_COMPRESS && p[1] == CILEN_BSD) {
350 * Peer wants us to use a different number of bits
351 * or a different version.
353 if (BSD_VERSION(p[2]) != BSD_CURRENT_VERSION)
354 try.bsd_compress = 0;
355 else if (BSD_NBITS(p[2]) < go->bsd_bits)
356 try.bsd_bits = BSD_NBITS(p[2]);
362 * Have a look at any remaining options...???
368 if (f->state != OPENED)
374 * ccp_rejci - reject some of our suggested compression methods.
382 ccp_options *go = &ccp_gotoptions[f->unit];
383 ccp_options try; /* options to request next time */
387 if (go->bsd_compress && len >= CILEN_BSD
388 && p[0] == CI_BSD_COMPRESS && p[1] == CILEN_BSD) {
389 if (p[2] != BSD_MAKE_OPT(BSD_CURRENT_VERSION, go->bsd_bits))
391 try.bsd_compress = 0;
399 if (f->state != OPENED)
406 * ccp_reqci - processed a received configure-request.
407 * Returns CONFACK, CONFNAK or CONFREJ and the packet modified
411 ccp_reqci(f, p, lenp, dont_nak)
419 int len, clen, type, nb;
420 ccp_options *ho = &ccp_hisoptions[f->unit];
421 ccp_options *ao = &ccp_allowoptions[f->unit];
427 memset(ho, 0, sizeof(ccp_options));
431 if (len < 2 || p[1] < 2 || p[1] > len) {
441 case CI_BSD_COMPRESS:
442 if (!ao->bsd_compress || clen != CILEN_BSD) {
447 ho->bsd_compress = 1;
448 ho->bsd_bits = nb = BSD_NBITS(p[2]);
449 if (BSD_VERSION(p[2]) != BSD_CURRENT_VERSION
450 || nb > ao->bsd_bits) {
453 } else if (nb < MIN_BSD_BITS) {
455 } else if (!ccp_test(f->unit, p, CILEN_BSD, 1)) {
456 if (nb > MIN_BSD_BITS) {
462 if (newret == CONFNAK && !dont_nak) {
463 p[2] = BSD_MAKE_OPT(BSD_CURRENT_VERSION, nb);
473 if (!(newret == CONFACK || newret == CONFNAK && ret == CONFREJ)) {
474 /* we're returning this option */
477 BCOPY(p, retp, clen);
491 * CCP has come up - inform the kernel driver.
497 ccp_options *go = &ccp_gotoptions[f->unit];
498 ccp_options *ho = &ccp_hisoptions[f->unit];
500 ccp_flags_set(f->unit, 1, 1);
501 if (go->bsd_compress || ho->bsd_compress)
502 syslog(LOG_NOTICE, "%s enabled",
503 go->bsd_compress? ho->bsd_compress? "Compression":
504 "Receive compression": "Transmit compression");
508 * CCP has gone down - inform the kernel driver.
514 if (ccp_localstate[f->unit] & RACK_PENDING)
515 UNTIMEOUT(ccp_rack_timeout, (caddr_t) f);
516 ccp_localstate[f->unit] = 0;
517 ccp_flags_set(f->unit, 1, 0);
521 * Print the contents of a CCP packet.
523 char *ccp_codenames[] = {
524 "ConfReq", "ConfAck", "ConfNak", "ConfRej",
525 "TermReq", "TermAck", "CodeRej",
526 NULL, NULL, NULL, NULL, NULL, NULL,
527 "ResetReq", "ResetAck",
531 ccp_printpkt(p, plen, printer, arg)
534 void (*printer) __ARGS((void *, char *, ...));
542 if (plen < HEADERLEN)
546 len = (p[2] << 8) + p[3];
547 if (len < HEADERLEN || len > plen)
550 if (code >= 1 && code <= sizeof(ccp_codenames) / sizeof(char *)
551 && ccp_codenames[code-1] != NULL)
552 printer(arg, " %s", ccp_codenames[code-1]);
554 printer(arg, " code=0x%x", code);
555 printer(arg, " id=0x%x", id);
564 /* print list of possible compression methods */
568 if (optlen < 2 || optlen > len)
574 case CI_BSD_COMPRESS:
575 if (optlen >= CILEN_BSD) {
576 printer(arg, "bsd v%d %d", BSD_VERSION(p[2]),
583 printer(arg, " %.2x", *p++);
589 /* dump out the rest of the packet in hex */
591 printer(arg, " %.2x", *p++);
597 * We have received a packet that the decompressor failed to
598 * decompress. Here we would expect to issue a reset-request, but
599 * Motorola has a patent on resetting the compressor as a result of
600 * detecting an error in the decompressed data after decompression.
601 * (See US patent 5,130,993; international patent publication number
602 * WO 91/10289; Australian patent 73296/91.)
604 * So we ask the kernel whether the error was detected after
605 * decompression; if it was, we take CCP down, thus disabling
606 * compression :-(, otherwise we issue the reset-request.
609 ccp_datainput(unit, pkt, len)
617 if (f->state == OPENED) {
618 if (ccp_fatal_error(unit)) {
620 * Disable compression by taking CCP down.
622 syslog(LOG_ERR, "Lost compression sync: disabling compression");
626 * Send a reset-request to reset the peer's compressor.
627 * We don't do that if we are still waiting for an
628 * acknowledgement to a previous reset-request.
630 if (!(ccp_localstate[f->unit] & RACK_PENDING)) {
631 fsm_sdata(f, RESETREQ, f->reqid = ++f->id, NULL, 0);
632 TIMEOUT(ccp_rack_timeout, (caddr_t) f, RACKTIMEOUT);
633 ccp_localstate[f->unit] |= RACK_PENDING;
635 ccp_localstate[f->unit] |= RREQ_REPEAT;
641 * Timeout waiting for reset-ack.
644 ccp_rack_timeout(arg)
647 fsm *f = (fsm *) arg;
649 if (f->state == OPENED && ccp_localstate[f->unit] & RREQ_REPEAT) {
650 fsm_sdata(f, RESETREQ, f->reqid, NULL, 0);
651 TIMEOUT(ccp_rack_timeout, (caddr_t) f, RACKTIMEOUT);
652 ccp_localstate[f->unit] &= ~RREQ_REPEAT;
654 ccp_localstate[f->unit] &= ~RACK_PENDING;