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Member "slirp-1.0.16/src/ppp/ccp.c" of archive slirp-1.0.16.tar.gz:
/*
* ccp.c - PPP Compression Control Protocol.
*
* Copyright (c) 1994 The Australian National University.
* All rights reserved.
*
* Permission to use, copy, modify, and distribute this software and its
* documentation is hereby granted, provided that the above copyright
* notice appears in all copies. This software is provided without any
* warranty, express or implied. The Australian National University
* makes no representations about the suitability of this software for
* any purpose.
*
* IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
* PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
* THE AUSTRALIAN NATIONAL UNIVERSITY HAVE BEEN ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
* OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
* OR MODIFICATIONS.
*/
#ifndef lint
static char rcsid[] = "$Id: ccp.c,v 1.10 1995/06/06 01:52:23 paulus Exp $";
#endif
#include <syslog.h>
#include <slirp.h>
#include "ppp-comp.h"
#include "pppd.h"
#include "fsm.h"
#include "ccp.h"
fsm ccp_fsm[NUM_PPP];
ccp_options ccp_wantoptions[NUM_PPP]; /* what to request the peer to use */
ccp_options ccp_gotoptions[NUM_PPP]; /* what the peer agreed to do */
ccp_options ccp_allowoptions[NUM_PPP]; /* what we'll agree to do */
ccp_options ccp_hisoptions[NUM_PPP]; /* what we agreed to do */
/*
* Callbacks for fsm code.
*/
static void ccp_resetci __P((fsm *));
static int ccp_cilen __P((fsm *));
static void ccp_addci __P((fsm *, u_char *, int *));
static int ccp_ackci __P((fsm *, u_char *, int));
static int ccp_nakci __P((fsm *, u_char *, int));
static int ccp_rejci __P((fsm *, u_char *, int));
static int ccp_reqci __P((fsm *, u_char *, int *, int));
static void ccp_up __P((fsm *));
static void ccp_down __P((fsm *));
static int ccp_extcode __P((fsm *, int, int, u_char *, int));
static void ccp_rack_timeout __P(());
static fsm_callbacks ccp_callbacks = {
ccp_resetci,
ccp_cilen,
ccp_addci,
ccp_ackci,
ccp_nakci,
ccp_rejci,
ccp_reqci,
ccp_up,
ccp_down,
NULL,
NULL,
NULL,
NULL,
ccp_extcode,
"CCP"
};
/*
* Do we want / did we get any compression?
*/
#define ANY_COMPRESS(opt) ((opt).bsd_compress)
/*
* Local state (mainly for handling reset-reqs and reset-acks
*/
static int ccp_localstate[NUM_PPP];
#define RACK_PENDING 1 /* waiting for reset-ack */
#define RREQ_REPEAT 2 /* send another reset-req if no reset-ack */
#define RACKTIMEOUT 1 /* second */
/*
* ccp_init - initialize CCP.
*/
void
ccp_init(unit)
int unit;
{
fsm *f = &ccp_fsm[unit];
f->unit = unit;
f->protocol = PPP_CCP;
f->callbacks = &ccp_callbacks;
fsm_init(f);
memset(&ccp_wantoptions[unit], 0, sizeof(ccp_options));
memset(&ccp_gotoptions[unit], 0, sizeof(ccp_options));
memset(&ccp_allowoptions[unit], 0, sizeof(ccp_options));
memset(&ccp_hisoptions[unit], 0, sizeof(ccp_options));
ccp_wantoptions[0].bsd_compress = 1;
ccp_wantoptions[0].bsd_bits = 12; /* default value */
ccp_allowoptions[0].bsd_compress = 1;
ccp_allowoptions[0].bsd_bits = BSD_MAX_BITS;
}
/*
* ccp_open - CCP is allowed to come up.
*/
void
ccp_open(unit)
int unit;
{
fsm *f = &ccp_fsm[unit];
if (f->state != OPENED)
ccp_flags_set(unit, 1, 0);
if (!ANY_COMPRESS(ccp_wantoptions[unit]))
f->flags |= OPT_SILENT;
fsm_open(f);
}
/*
* ccp_close - Terminate CCP.
*/
void
ccp_close(unit)
int unit;
{
ccp_flags_set(unit, 0, 0);
fsm_close(&ccp_fsm[unit]);
}
/*
* ccp_lowerup - we may now transmit CCP packets.
*/
void
ccp_lowerup(unit)
int unit;
{
fsm_lowerup(&ccp_fsm[unit]);
}
/*
* ccp_lowerdown - we may not transmit CCP packets.
*/
void
ccp_lowerdown(unit)
int unit;
{
fsm_lowerdown(&ccp_fsm[unit]);
}
/*
* ccp_input - process a received CCP packet.
*/
void
ccp_input(unit, p, len)
int unit;
u_char *p;
int len;
{
fsm *f = &ccp_fsm[unit];
int oldstate;
/*
* Check for a terminate-request so we can print a message.
*/
oldstate = f->state;
fsm_input(f, p, len);
if (oldstate == OPENED && p[0] == TERMREQ && f->state != OPENED)
do_syslog(LOG_NOTICE, "Compression disabled by peer.");
/*
* If we get a terminate-ack and we're not asking for compression,
* close CCP.
*/
if (oldstate == REQSENT && p[0] == TERMACK
&& !ANY_COMPRESS(ccp_gotoptions[unit]))
ccp_close(unit);
}
/*
* Handle a CCP-specific code.
*/
static int
ccp_extcode(f, code, id, p, len)
fsm *f;
int code, id;
u_char *p;
int len;
{
switch (code) {
case CCP_RESETREQ:
if (f->state != OPENED)
break;
/* send a reset-ack, which the transmitter will see and
reset its compression state. */
fsm_sdata(f, CCP_RESETACK, id, NULL, 0);
break;
case CCP_RESETACK:
if (ccp_localstate[f->unit] & RACK_PENDING && id == f->reqid) {
ccp_localstate[f->unit] &= ~(RACK_PENDING | RREQ_REPEAT);
UNTIMEOUT(ccp_rack_timeout, (caddr_t) f);
}
break;
default:
return 0;
}
return 1;
}
/*
* ccp_protrej - peer doesn't talk CCP.
*/
void
ccp_protrej(unit)
int unit;
{
ccp_flags_set(unit, 0, 0);
fsm_lowerdown(&ccp_fsm[unit]);
}
/*
* ccp_resetci - initialize at start of negotiation.
*/
static void
ccp_resetci(f)
fsm *f;
{
ccp_options *go = &ccp_gotoptions[f->unit];
u_char opt_buf[16];
*go = ccp_wantoptions[f->unit];
if (go->bsd_compress) {
opt_buf[0] = CI_BSD_COMPRESS;
opt_buf[1] = CILEN_BSD_COMPRESS;
opt_buf[2] = BSD_MAKE_OPT(BSD_CURRENT_VERSION, go->bsd_bits);
if (!ccp_test(f->unit, opt_buf, CILEN_BSD_COMPRESS, 0))
go->bsd_compress = 0;
}
}
/*
* ccp_cilen - Return total length of our configuration info.
*/
static int
ccp_cilen(f)
fsm *f;
{
ccp_options *go = &ccp_gotoptions[f->unit];
return (go->bsd_compress? CILEN_BSD_COMPRESS: 0);
}
/*
* ccp_addci - put our requests in a packet.
*/
static void
ccp_addci(f, p, lenp)
fsm *f;
u_char *p;
int *lenp;
{
ccp_options *go = &ccp_gotoptions[f->unit];
u_char *p0 = p;
if (go->bsd_compress) {
p[0] = CI_BSD_COMPRESS;
p[1] = CILEN_BSD_COMPRESS;
p[2] = BSD_MAKE_OPT(BSD_CURRENT_VERSION, go->bsd_bits);
if (ccp_test(f->unit, p, CILEN_BSD_COMPRESS, 0))
p += CILEN_BSD_COMPRESS;
else
go->bsd_compress = 0;
}
*lenp = p - p0;
}
/*
* ccp_ackci - process a received configure-ack, and return
* 1 iff the packet was OK.
*/
static int
ccp_ackci(f, p, len)
fsm *f;
u_char *p;
int len;
{
ccp_options *go = &ccp_gotoptions[f->unit];
if (go->bsd_compress) {
if (len < CILEN_BSD_COMPRESS
|| p[0] != CI_BSD_COMPRESS || p[1] != CILEN_BSD_COMPRESS
|| p[2] != BSD_MAKE_OPT(BSD_CURRENT_VERSION, go->bsd_bits))
return 0;
p += CILEN_BSD_COMPRESS;
len -= CILEN_BSD_COMPRESS;
}
if (len != 0)
return 0;
return 1;
}
/*
* ccp_nakci - process received configure-nak.
* Returns 1 iff the nak was OK.
*/
static int
ccp_nakci(f, p, len)
fsm *f;
u_char *p;
int len;
{
ccp_options *go = &ccp_gotoptions[f->unit];
ccp_options no; /* options we've seen already */
ccp_options try; /* options to ask for next time */
memset(&no, 0, sizeof(no));
try = *go;
if (go->bsd_compress && !no.bsd_compress && len >= CILEN_BSD_COMPRESS
&& p[0] == CI_BSD_COMPRESS && p[1] == CILEN_BSD_COMPRESS) {
no.bsd_compress = 1;
/*
* Peer wants us to use a different number of bits
* or a different version.
*/
if (BSD_VERSION(p[2]) != BSD_CURRENT_VERSION)
try.bsd_compress = 0;
else if (BSD_NBITS(p[2]) < go->bsd_bits)
try.bsd_bits = BSD_NBITS(p[2]);
p += CILEN_BSD_COMPRESS;
len -= CILEN_BSD_COMPRESS;
}
/*
* Have a look at any remaining options...???
*/
if (len != 0)
return 0;
if (f->state != OPENED)
*go = try;
return 1;
}
/*
* ccp_rejci - reject some of our suggested compression methods.
*/
static int
ccp_rejci(f, p, len)
fsm *f;
u_char *p;
int len;
{
ccp_options *go = &ccp_gotoptions[f->unit];
ccp_options try; /* options to request next time */
try = *go;
if (go->bsd_compress && len >= CILEN_BSD_COMPRESS
&& p[0] == CI_BSD_COMPRESS && p[1] == CILEN_BSD_COMPRESS) {
if (p[2] != BSD_MAKE_OPT(BSD_CURRENT_VERSION, go->bsd_bits))
return 0;
try.bsd_compress = 0;
p += CILEN_BSD_COMPRESS;
len -= CILEN_BSD_COMPRESS;
}
if (len != 0)
return 0;
if (f->state != OPENED)
*go = try;
return 1;
}
/*
* ccp_reqci - processed a received configure-request.
* Returns CONFACK, CONFNAK or CONFREJ and the packet modified
* appropriately.
*/
static int
ccp_reqci(f, p, lenp, dont_nak)
fsm *f;
u_char *p;
int *lenp;
int dont_nak;
{
int ret, newret;
u_char *p0, *retp;
int len, clen, type, nb;
ccp_options *ho = &ccp_hisoptions[f->unit];
ccp_options *ao = &ccp_allowoptions[f->unit];
ret = CONFACK;
retp = p0 = p;
len = *lenp;
memset(ho, 0, sizeof(ccp_options));
while (len > 0) {
newret = CONFACK;
if (len < 2 || p[1] < 2 || p[1] > len) {
/* length is bad */
clen = len;
newret = CONFREJ;
} else {
type = p[0];
clen = p[1];
switch (type) {
case CI_BSD_COMPRESS:
if (!ao->bsd_compress || clen != CILEN_BSD_COMPRESS) {
newret = CONFREJ;
break;
}
ho->bsd_compress = 1;
ho->bsd_bits = nb = BSD_NBITS(p[2]);
if (BSD_VERSION(p[2]) != BSD_CURRENT_VERSION
|| nb > ao->bsd_bits) {
newret = CONFNAK;
nb = ao->bsd_bits;
} else if (nb < BSD_MIN_BITS) {
newret = CONFREJ;
} else if (!ccp_test(f->unit, p, CILEN_BSD_COMPRESS, 1)) {
if (nb > BSD_MIN_BITS) {
--nb;
newret = CONFNAK;
} else
newret = CONFREJ;
}
if (newret == CONFNAK && !dont_nak) {
p[2] = BSD_MAKE_OPT(BSD_CURRENT_VERSION, nb);
}
break;
default:
newret = CONFREJ;
}
}
if (newret == CONFNAK && dont_nak)
newret = CONFREJ;
if (!(newret == CONFACK || newret == CONFNAK && ret == CONFREJ)) {
/* we're returning this option */
if (newret == CONFREJ && ret == CONFNAK)
retp = p0;
ret = newret;
if (p != retp)
BCOPY(p, retp, clen);
retp += clen;
}
p += clen;
len -= clen;
}
if (ret != CONFACK)
*lenp = retp - p0;
return ret;
}
/*
* CCP has come up - inform the kernel driver.
*/
static void
ccp_up(f)
fsm *f;
{
ccp_options *go = &ccp_gotoptions[f->unit];
ccp_options *ho = &ccp_hisoptions[f->unit];
ccp_flags_set(f->unit, 1, 1);
if (go->bsd_compress || ho->bsd_compress)
do_syslog(LOG_NOTICE, "%s enabled",
go->bsd_compress? ho->bsd_compress? "Compression":
"Receive compression": "Transmit compression");
}
/*
* CCP has gone down - inform the kernel driver.
*/
static void
ccp_down(f)
fsm *f;
{
if (ccp_localstate[f->unit] & RACK_PENDING)
UNTIMEOUT(ccp_rack_timeout, (caddr_t) f);
ccp_localstate[f->unit] = 0;
ccp_flags_set(f->unit, 1, 0);
}
/*
* Print the contents of a CCP packet.
*/
char *ccp_codenames[] = {
"ConfReq", "ConfAck", "ConfNak", "ConfRej",
"TermReq", "TermAck", "CodeRej",
NULL, NULL, NULL, NULL, NULL, NULL,
"ResetReq", "ResetAck",
};
int
ccp_printpkt(p, plen, printer, arg)
u_char *p;
int plen;
void (*printer) __P((void *, char *, ...));
void *arg;
{
u_char *p0, *optend;
int code, id, len;
int optlen;
p0 = p;
if (plen < HEADERLEN)
return 0;
code = p[0];
id = p[1];
len = (p[2] << 8) + p[3];
if (len < HEADERLEN || len > plen)
return 0;
if (code >= 1 && code <= sizeof(ccp_codenames) / sizeof(char *)
&& ccp_codenames[code-1] != NULL)
printer(arg, " %s", ccp_codenames[code-1]);
else
printer(arg, " code=0x%x", code);
printer(arg, " id=0x%x", id);
len -= HEADERLEN;
p += HEADERLEN;
switch (code) {
case CONFREQ:
case CONFACK:
case CONFNAK:
case CONFREJ:
/* print list of possible compression methods */
while (len >= 2) {
code = p[0];
optlen = p[1];
if (optlen < 2 || optlen > len)
break;
printer(arg, " <");
len -= optlen;
optend = p + optlen;
switch (code) {
case CI_BSD_COMPRESS:
if (optlen >= CILEN_BSD_COMPRESS) {
printer(arg, "bsd v%d %d", BSD_VERSION(p[2]),
BSD_NBITS(p[2]));
p += CILEN_BSD_COMPRESS;
}
break;
}
while (p < optend)
printer(arg, " %.2x", *p++);
printer(arg, ">");
}
break;
}
/* dump out the rest of the packet in hex */
while (--len >= 0)
printer(arg, " %.2x", *p++);
return p - p0;
}
/*
* We have received a packet that the decompressor failed to
* decompress. Here we would expect to issue a reset-request, but
* Motorola has a patent on resetting the compressor as a result of
* detecting an error in the decompressed data after decompression.
* (See US patent 5,130,993; international patent publication number
* WO 91/10289; Australian patent 73296/91.)
*
* So we ask the kernel whether the error was detected after
* decompression; if it was, we take CCP down, thus disabling
* compression :-(, otherwise we issue the reset-request.
*/
void
ccp_datainput(unit, pkt, len)
int unit;
u_char *pkt;
int len;
{
fsm *f;
f = &ccp_fsm[unit];
if (f->state == OPENED) {
if (ccp_fatal_error(unit)) {
/*
* Disable compression by taking CCP down.
*/
do_syslog(LOG_ERR, "Lost compression sync: disabling compression");
ccp_close(unit);
} else {
/*
* Send a reset-request to reset the peer's compressor.
* We don't do that if we are still waiting for an
* acknowledgement to a previous reset-request.
*/
if (!(ccp_localstate[f->unit] & RACK_PENDING)) {
fsm_sdata(f, CCP_RESETREQ, f->reqid = ++f->id, NULL, 0);
TIMEOUT(ccp_rack_timeout, (caddr_t) f, RACKTIMEOUT);
ccp_localstate[f->unit] |= RACK_PENDING;
} else
ccp_localstate[f->unit] |= RREQ_REPEAT;
}
}
}
/*
* Timeout waiting for reset-ack.
*/
static void
ccp_rack_timeout(arg)
caddr_t arg;
{
fsm *f = (fsm *) arg;
if (f->state == OPENED && ccp_localstate[f->unit] & RREQ_REPEAT) {
fsm_sdata(f, CCP_RESETREQ, f->reqid, NULL, 0);
TIMEOUT(ccp_rack_timeout, (caddr_t) f, RACKTIMEOUT);
ccp_localstate[f->unit] &= ~RREQ_REPEAT;
} else
ccp_localstate[f->unit] &= ~RACK_PENDING;
}