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| Current File : //usr/src/contrib/telnet/telnetd/slc.c |
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if 0
#ifndef lint
static const char sccsid[] = "@(#)slc.c 8.2 (Berkeley) 5/30/95";
#endif
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/contrib/telnet/telnetd/slc.c 114630 2003-05-04 02:54:49Z obrien $");
#include "telnetd.h"
#ifdef LINEMODE
/*
* local variables
*/
static unsigned char *def_slcbuf = (unsigned char *)0;
static int def_slclen = 0;
static int slcchange; /* change to slc is requested */
static unsigned char *slcptr; /* pointer into slc buffer */
static unsigned char slcbuf[NSLC*6]; /* buffer for slc negotiation */
/*
* send_slc
*
* Write out the current special characters to the client.
*/
void
send_slc(void)
{
int i;
/*
* Send out list of triplets of special characters
* to client. We only send info on the characters
* that are currently supported.
*/
for (i = 1; i <= NSLC; i++) {
if ((slctab[i].defset.flag & SLC_LEVELBITS) == SLC_NOSUPPORT)
continue;
add_slc((unsigned char)i, slctab[i].current.flag,
slctab[i].current.val);
}
} /* end of send_slc */
/*
* default_slc
*
* Set pty special characters to all the defaults.
*/
static void
default_slc(void)
{
int i;
for (i = 1; i <= NSLC; i++) {
slctab[i].current.val = slctab[i].defset.val;
if (slctab[i].current.val == (cc_t)(_POSIX_VDISABLE))
slctab[i].current.flag = SLC_NOSUPPORT;
else
slctab[i].current.flag = slctab[i].defset.flag;
if (slctab[i].sptr) {
*(slctab[i].sptr) = slctab[i].defset.val;
}
}
slcchange = 1;
} /* end of default_slc */
#endif /* LINEMODE */
/*
* get_slc_defaults
*
* Initialize the slc mapping table.
*/
void
get_slc_defaults(void)
{
int i;
init_termbuf();
for (i = 1; i <= NSLC; i++) {
slctab[i].defset.flag =
spcset(i, &slctab[i].defset.val, &slctab[i].sptr);
slctab[i].current.flag = SLC_NOSUPPORT;
slctab[i].current.val = 0;
}
} /* end of get_slc_defaults */
#ifdef LINEMODE
/*
* add_slc
*
* Add an slc triplet to the slc buffer.
*/
void
add_slc(char func, char flag, cc_t val)
{
if ((*slcptr++ = (unsigned char)func) == 0xff)
*slcptr++ = 0xff;
if ((*slcptr++ = (unsigned char)flag) == 0xff)
*slcptr++ = 0xff;
if ((*slcptr++ = (unsigned char)val) == 0xff)
*slcptr++ = 0xff;
} /* end of add_slc */
/*
* start_slc
*
* Get ready to process incoming slc's and respond to them.
*
* The parameter getit is non-zero if it is necessary to grab a copy
* of the terminal control structures.
*/
void
start_slc(int getit)
{
slcchange = 0;
if (getit)
init_termbuf();
(void) sprintf((char *)slcbuf, "%c%c%c%c",
IAC, SB, TELOPT_LINEMODE, LM_SLC);
slcptr = slcbuf + 4;
} /* end of start_slc */
/*
* end_slc
*
* Finish up the slc negotiation. If something to send, then send it.
*/
int
end_slc(unsigned char **bufp)
{
int len;
/*
* If a change has occured, store the new terminal control
* structures back to the terminal driver.
*/
if (slcchange) {
set_termbuf();
}
/*
* If the pty state has not yet been fully processed and there is a
* deferred slc request from the client, then do not send any
* sort of slc negotiation now. We will respond to the client's
* request very soon.
*/
if (def_slcbuf && (terminit() == 0)) {
return(0);
}
if (slcptr > (slcbuf + 4)) {
if (bufp) {
*bufp = &slcbuf[4];
return(slcptr - slcbuf - 4);
} else {
(void) sprintf((char *)slcptr, "%c%c", IAC, SE);
slcptr += 2;
len = slcptr - slcbuf;
output_datalen(slcbuf, len);
netflush(); /* force it out immediately */
DIAG(TD_OPTIONS, printsub('>', slcbuf+2, len-2););
}
}
return (0);
} /* end of end_slc */
/*
* process_slc
*
* Figure out what to do about the client's slc
*/
void
process_slc(unsigned char func, unsigned char flag, cc_t val)
{
int hislevel, mylevel, ack;
/*
* Ensure that we know something about this function
*/
if (func > NSLC) {
add_slc(func, SLC_NOSUPPORT, 0);
return;
}
/*
* Process the special case requests of 0 SLC_DEFAULT 0
* and 0 SLC_VARIABLE 0. Be a little forgiving here, don't
* worry about whether the value is actually 0 or not.
*/
if (func == 0) {
if ((flag = flag & SLC_LEVELBITS) == SLC_DEFAULT) {
default_slc();
send_slc();
} else if (flag == SLC_VARIABLE) {
send_slc();
}
return;
}
/*
* Appears to be a function that we know something about. So
* get on with it and see what we know.
*/
hislevel = flag & SLC_LEVELBITS;
mylevel = slctab[func].current.flag & SLC_LEVELBITS;
ack = flag & SLC_ACK;
/*
* ignore the command if:
* the function value and level are the same as what we already have;
* or the level is the same and the ack bit is set
*/
if (hislevel == mylevel && (val == slctab[func].current.val || ack)) {
return;
} else if (ack) {
/*
* If we get here, we got an ack, but the levels don't match.
* This shouldn't happen. If it does, it is probably because
* we have sent two requests to set a variable without getting
* a response between them, and this is the first response.
* So, ignore it, and wait for the next response.
*/
return;
} else {
change_slc(func, flag, val);
}
} /* end of process_slc */
/*
* change_slc
*
* Process a request to change one of our special characters.
* Compare client's request with what we are capable of supporting.
*/
void
change_slc(char func, char flag, cc_t val)
{
int hislevel, mylevel;
hislevel = flag & SLC_LEVELBITS;
mylevel = slctab[(int)func].defset.flag & SLC_LEVELBITS;
/*
* If client is setting a function to NOSUPPORT
* or DEFAULT, then we can easily and directly
* accomodate the request.
*/
if (hislevel == SLC_NOSUPPORT) {
slctab[(int)func].current.flag = flag;
slctab[(int)func].current.val = (cc_t)_POSIX_VDISABLE;
flag |= SLC_ACK;
add_slc(func, flag, val);
return;
}
if (hislevel == SLC_DEFAULT) {
/*
* Special case here. If client tells us to use
* the default on a function we don't support, then
* return NOSUPPORT instead of what we may have as a
* default level of DEFAULT.
*/
if (mylevel == SLC_DEFAULT) {
slctab[(int)func].current.flag = SLC_NOSUPPORT;
} else {
slctab[(int)func].current.flag = slctab[(int)func].defset.flag;
}
slctab[(int)func].current.val = slctab[(int)func].defset.val;
add_slc(func, slctab[(int)func].current.flag,
slctab[(int)func].current.val);
return;
}
/*
* Client wants us to change to a new value or he
* is telling us that he can't change to our value.
* Some of the slc's we support and can change,
* some we do support but can't change,
* and others we don't support at all.
* If we can change it then we have a pointer to
* the place to put the new value, so change it,
* otherwise, continue the negotiation.
*/
if (slctab[(int)func].sptr) {
/*
* We can change this one.
*/
slctab[(int)func].current.val = val;
*(slctab[(int)func].sptr) = val;
slctab[(int)func].current.flag = flag;
flag |= SLC_ACK;
slcchange = 1;
add_slc(func, flag, val);
} else {
/*
* It is not possible for us to support this
* request as he asks.
*
* If our level is DEFAULT, then just ack whatever was
* sent.
*
* If he can't change and we can't change,
* then degenerate to NOSUPPORT.
*
* Otherwise we send our level back to him, (CANTCHANGE
* or NOSUPPORT) and if CANTCHANGE, send
* our value as well.
*/
if (mylevel == SLC_DEFAULT) {
slctab[(int)func].current.flag = flag;
slctab[(int)func].current.val = val;
flag |= SLC_ACK;
} else if (hislevel == SLC_CANTCHANGE &&
mylevel == SLC_CANTCHANGE) {
flag &= ~SLC_LEVELBITS;
flag |= SLC_NOSUPPORT;
slctab[(int)func].current.flag = flag;
} else {
flag &= ~SLC_LEVELBITS;
flag |= mylevel;
slctab[(int)func].current.flag = flag;
if (mylevel == SLC_CANTCHANGE) {
slctab[(int)func].current.val =
slctab[(int)func].defset.val;
val = slctab[(int)func].current.val;
}
}
add_slc(func, flag, val);
}
} /* end of change_slc */
#if defined(USE_TERMIO) && (VEOF == VMIN)
cc_t oldeofc = '\004';
#endif
/*
* check_slc
*
* Check the special characters in use and notify the client if any have
* changed. Only those characters that are capable of being changed are
* likely to have changed. If a local change occurs, kick the support level
* and flags up to the defaults.
*/
void
check_slc(void)
{
int i;
for (i = 1; i <= NSLC; i++) {
#if defined(USE_TERMIO) && (VEOF == VMIN)
/*
* In a perfect world this would be a neat little
* function. But in this world, we should not notify
* client of changes to the VEOF char when
* ICANON is off, because it is not representing
* a special character.
*/
if (i == SLC_EOF) {
if (!tty_isediting())
continue;
else if (slctab[i].sptr)
oldeofc = *(slctab[i].sptr);
}
#endif /* defined(USE_TERMIO) && defined(SYSV_TERMIO) */
if (slctab[i].sptr &&
(*(slctab[i].sptr) != slctab[i].current.val)) {
slctab[i].current.val = *(slctab[i].sptr);
if (*(slctab[i].sptr) == (cc_t)_POSIX_VDISABLE)
slctab[i].current.flag = SLC_NOSUPPORT;
else
slctab[i].current.flag = slctab[i].defset.flag;
add_slc((unsigned char)i, slctab[i].current.flag,
slctab[i].current.val);
}
}
} /* check_slc */
/*
* do_opt_slc
*
* Process an slc option buffer. Defer processing of incoming slc's
* until after the terminal state has been processed. Save the first slc
* request that comes along, but discard all others.
*
* ptr points to the beginning of the buffer, len is the length.
*/
void
do_opt_slc(unsigned char *ptr, int len)
{
unsigned char func, flag;
cc_t val;
unsigned char *end = ptr + len;
if (terminit()) { /* go ahead */
while (ptr < end) {
func = *ptr++;
if (ptr >= end) break;
flag = *ptr++;
if (ptr >= end) break;
val = (cc_t)*ptr++;
process_slc(func, flag, val);
}
} else {
/*
* save this slc buffer if it is the first, otherwise dump
* it.
*/
if (def_slcbuf == (unsigned char *)0) {
def_slclen = len;
def_slcbuf = (unsigned char *)malloc((unsigned)len);
if (def_slcbuf == (unsigned char *)0)
return; /* too bad */
memmove(def_slcbuf, ptr, len);
}
}
} /* end of do_opt_slc */
/*
* deferslc
*
* Do slc stuff that was deferred.
*/
void
deferslc(void)
{
if (def_slcbuf) {
start_slc(1);
do_opt_slc(def_slcbuf, def_slclen);
(void) end_slc(0);
free(def_slcbuf);
def_slcbuf = (unsigned char *)0;
def_slclen = 0;
}
} /* end of deferslc */
#endif /* LINEMODE */