void
telrcv()
{
register int c;
static int state = TS_DATA;
#if defined(CRAY2) && defined(UNICOS5)
char *opfrontp = pfrontp;
#endif
while (ncc > 0) {
if ((&ptyobuf[BUFSIZ] - pfrontp) < 2)
break;
c = *netip++ & 0377, ncc--;
switch (state) {
case TS_CR:
state = TS_DATA;
/* Strip off \n or \0 after a \r */
if ((c == 0) || (c == '\n')) {
break;
}
/* FALL THROUGH */
case TS_DATA:
if (c == IAC) {
state = TS_IAC;
break;
}
/*
* We now map \r\n ==> \r for pragmatic reasons.
* Many client implementations send \r\n when
* the user hits the CarriageReturn key.
*
* We USED to map \r\n ==> \n, since \r\n says
* that we want to be in column 1 of the next
* printable line, and \n is the standard
* unix way of saying that (\r is only good
* if CRMOD is set, which it normally is).
*/
if ((c == '\r') && his_state_is_wont(TELOPT_BINARY)) {
int nc = *netip;
#ifdef LINEMODE
/*
* If we are operating in linemode,
* convert to local end-of-line.
*/
if (linemode && (ncc > 0) && (('\n' == nc) ||
((0 == nc) && tty_iscrnl())) ) {
netip++;
ncc--;
c = '\n';
} else
#endif
{
state = TS_CR;
}
}
*pfrontp++ = c;
break;
case TS_IAC:
gotiac:
switch (c) {
/*
* Send the process on the pty side an
* interrupt. Do this with a NULL or
* interrupt char; depending on the tty mode.
*/
case IP:
DIAG(TD_OPTIONS,
printoption("td: recv IAC", c));
interrupt();
break;
case BREAK:
DIAG(TD_OPTIONS,
printoption("td: recv IAC", c));
sendbrk();
break;
/*
* Are You There?
*/
case AYT:
DIAG(TD_OPTIONS,
printoption("td: recv IAC", c));
recv_ayt();
break;
/*
* Abort Output
*/
case AO:
{
DIAG(TD_OPTIONS,
printoption("td: recv IAC", c));
ptyflush(); /* half-hearted */
init_termbuf();
if (slctab[SLC_AO].sptr &&
*slctab[SLC_AO].sptr != (cc_t)(_POSIX_VDISABLE)) {
*pfrontp++ =
(unsigned char)*slctab[SLC_AO].sptr;
}
netclear(); /* clear buffer back */
*nfrontp++ = IAC;
*nfrontp++ = DM;
neturg = nfrontp-1; /* off by one XXX */
DIAG(TD_OPTIONS,
printoption("td: send IAC", DM));
break;
}
/*
* Erase Character and
* Erase Line
*/
case EC:
case EL:
{
cc_t ch;
DIAG(TD_OPTIONS,
printoption("td: recv IAC", c));
ptyflush(); /* half-hearted */
init_termbuf();
if (c == EC)
ch = *slctab[SLC_EC].sptr;
else
ch = *slctab[SLC_EL].sptr;
if (ch != (cc_t)(_POSIX_VDISABLE))
*pfrontp++ = (unsigned char)ch;
break;
}
/*
* Check for urgent data...
*/
case DM:
DIAG(TD_OPTIONS,
printoption("td: recv IAC", c));
SYNCHing = stilloob(net);
settimer(gotDM);
break;
/*
* Begin option subnegotiation...
*/
case SB:
state = TS_SB;
SB_CLEAR();
continue;
case WILL:
state = TS_WILL;
continue;
case WONT:
state = TS_WONT;
continue;
case DO:
state = TS_DO;
continue;
case DONT:
state = TS_DONT;
continue;
case EOR:
if (his_state_is_will(TELOPT_EOR))
doeof();
break;
/*
* Handle RFC 10xx Telnet linemode option additions
* to command stream (EOF, SUSP, ABORT).
*/
case xEOF:
doeof();
break;
case SUSP:
sendsusp();
break;
case ABORT:
sendbrk();
break;
case IAC:
*pfrontp++ = c;
break;
}
state = TS_DATA;
break;
case TS_SB:
if (c == IAC) {
state = TS_SE;
} else {
SB_ACCUM(c);
}
break;
case TS_SE:
if (c != SE) {
if (c != IAC) {
/*
* bad form of suboption negotiation.
* handle it in such a way as to avoid
* damage to local state. Parse
* suboption buffer found so far,
* then treat remaining stream as
* another command sequence.
*/
/* for DIAGNOSTICS */
SB_ACCUM(IAC);
SB_ACCUM(c);
subpointer -= 2;
SB_TERM();
suboption();
state = TS_IAC;
goto gotiac;
}
SB_ACCUM(c);
state = TS_SB;
} else {
/* for DIAGNOSTICS */
SB_ACCUM(IAC);
SB_ACCUM(SE);
subpointer -= 2;
SB_TERM();
suboption(); /* handle sub-option */
state = TS_DATA;
}
break;
case TS_WILL:
willoption(c);
state = TS_DATA;
continue;
case TS_WONT:
wontoption(c);
state = TS_DATA;
continue;
case TS_DO:
dooption(c);
state = TS_DATA;
continue;
case TS_DONT:
dontoption(c);
state = TS_DATA;
continue;
default:
syslog(LOG_ERR, "telnetd: panic state=%d\n", state);
printf("telnetd: panic state=%d\n", state);
exit(1);
}
}
#if defined(CRAY2) && defined(UNICOS5)
if (!linemode) {
char xptyobuf[BUFSIZ+NETSLOP];
char xbuf2[BUFSIZ];
register char *cp;
int n = pfrontp - opfrontp, oc;
memmove(xptyobuf, opfrontp, n);
pfrontp = opfrontp;
pfrontp += term_input(xptyobuf, pfrontp, n, BUFSIZ+NETSLOP,
xbuf2, &oc, BUFSIZ);
for (cp = xbuf2; oc > 0; --oc)
if ((*nfrontp++ = *cp++) == IAC)
*nfrontp++ = IAC;
}
#endif /* defined(CRAY2) && defined(UNICOS5) */
} /* end of telrcv */
int
telrcv(void)
{
int c;
int scc;
unsigned char *sbp;
int count;
int returnValue = 0;
scc = 0;
count = 0;
while (TTYROOM() > 2) {
if (scc == 0) {
if (count) {
ring_consumed(&netiring, count);
returnValue = 1;
count = 0;
}
sbp = netiring.consume;
scc = ring_full_consecutive(&netiring);
if (scc == 0) {
/* No more data coming in */
break;
}
}
c = *sbp++ & 0xff, scc--; count++;
#ifdef ENCRYPTION
if (decrypt_input)
c = (*decrypt_input)(c);
#endif /* ENCRYPTION */
switch (telrcv_state) {
case TS_CR:
telrcv_state = TS_DATA;
if (c == '\0') {
break; /* Ignore \0 after CR */
}
else if ((c == '\n') && my_want_state_is_dont(TELOPT_ECHO) && !crmod) {
TTYADD(c);
break;
}
/* Else, fall through */
case TS_DATA:
if (c == IAC) {
telrcv_state = TS_IAC;
break;
}
/*
* The 'crmod' hack (see following) is needed
* since we can't * set CRMOD on output only.
* Machines like MULTICS like to send \r without
* \n; since we must turn off CRMOD to get proper
* input, the mapping is done here (sigh).
*/
if ((c == '\r') && my_want_state_is_dont(TELOPT_BINARY)) {
if (scc > 0) {
c = *sbp&0xff;
#ifdef ENCRYPTION
if (decrypt_input)
c = (*decrypt_input)(c);
#endif /* ENCRYPTION */
if (c == 0) {
sbp++, scc--; count++;
/* a "true" CR */
TTYADD('\r');
} else if (my_want_state_is_dont(TELOPT_ECHO) &&
(c == '\n')) {
sbp++, scc--; count++;
TTYADD('\n');
} else {
#ifdef ENCRYPTION
if (decrypt_input)
(*decrypt_input)(-1);
#endif /* ENCRYPTION */
TTYADD('\r');
if (crmod) {
TTYADD('\n');
}
}
} else {
telrcv_state = TS_CR;
TTYADD('\r');
if (crmod) {
TTYADD('\n');
}
}
} else {
TTYADD(c);
}
continue;
case TS_IAC:
process_iac:
switch (c) {
case WILL:
telrcv_state = TS_WILL;
continue;
case WONT:
telrcv_state = TS_WONT;
continue;
case DO:
telrcv_state = TS_DO;
continue;
case DONT:
telrcv_state = TS_DONT;
continue;
case DM:
/*
* We may have missed an urgent notification,
* so make sure we flush whatever is in the
* buffer currently.
*/
printoption("RCVD", IAC, DM);
SYNCHing = 1;
(void) ttyflush(1);
SYNCHing = stilloob();
settimer(gotDM);
break;
case SB:
SB_CLEAR();
telrcv_state = TS_SB;
continue;
case IAC:
TTYADD(IAC);
break;
case NOP:
case GA:
default:
printoption("RCVD", IAC, c);
break;
}
telrcv_state = TS_DATA;
continue;
case TS_WILL:
printoption("RCVD", WILL, c);
willoption(c);
telrcv_state = TS_DATA;
continue;
case TS_WONT:
printoption("RCVD", WONT, c);
wontoption(c);
telrcv_state = TS_DATA;
continue;
case TS_DO:
printoption("RCVD", DO, c);
dooption(c);
if (c == TELOPT_NAWS) {
sendnaws();
} else if (c == TELOPT_LFLOW) {
localflow = 1;
setcommandmode();
setconnmode(0);
}
telrcv_state = TS_DATA;
continue;
case TS_DONT:
printoption("RCVD", DONT, c);
dontoption(c);
flushline = 1;
setconnmode(0); /* set new tty mode (maybe) */
telrcv_state = TS_DATA;
continue;
case TS_SB:
if (c == IAC) {
telrcv_state = TS_SE;
} else {
SB_ACCUM(c);
}
continue;
case TS_SE:
if (c != SE) {
if (c != IAC) {
/*
* This is an error. We only expect to get
* "IAC IAC" or "IAC SE". Several things may
* have happend. An IAC was not doubled, the
* IAC SE was left off, or another option got
* inserted into the suboption are all possibilities.
* If we assume that the IAC was not doubled,
* and really the IAC SE was left off, we could
* get into an infinate loop here. So, instead,
* we terminate the suboption, and process the
* partial suboption if we can.
*/
SB_ACCUM(IAC);
SB_ACCUM(c);
subpointer -= 2;
SB_TERM();
printoption("In SUBOPTION processing, RCVD", IAC, c);
suboption(); /* handle sub-option */
telrcv_state = TS_IAC;
goto process_iac;
}
SB_ACCUM(c);
telrcv_state = TS_SB;
} else {
SB_ACCUM(IAC);
SB_ACCUM(SE);
subpointer -= 2;
SB_TERM();
suboption(); /* handle sub-option */
telrcv_state = TS_DATA;
}
}
}
if (count)
ring_consumed(&netiring, count);
return returnValue||count;
}
/*
* Main loop. Select from pty and network, and
* hand data to telnet receiver finite state machine.
*/
void telnet(int f, int p)
{
int on = 1;
char *HE;
const char *IM;
/*
* Initialize the slc mapping table.
*/
get_slc_defaults();
/*
* Do some tests where it is desireable to wait for a response.
* Rather than doing them slowly, one at a time, do them all
* at once.
*/
if (my_state_is_wont(TELOPT_SGA))
send_will(TELOPT_SGA, 1);
/*
* Is the client side a 4.2 (NOT 4.3) system? We need to know this
* because 4.2 clients are unable to deal with TCP urgent data.
*
* To find out, we send out a "DO ECHO". If the remote system
* answers "WILL ECHO" it is probably a 4.2 client, and we note
* that fact ("WILL ECHO" ==> that the client will echo what
* WE, the server, sends it; it does NOT mean that the client will
* echo the terminal input).
*/
send_do(TELOPT_ECHO, 1);
#ifdef LINEMODE
if (his_state_is_wont(TELOPT_LINEMODE)) {
/*
* Query the peer for linemode support by trying to negotiate
* the linemode option.
*/
linemode = 0;
editmode = 0;
send_do(TELOPT_LINEMODE, 1); /* send do linemode */
}
#endif /* LINEMODE */
/*
* Send along a couple of other options that we wish to negotiate.
*/
send_do(TELOPT_NAWS, 1);
send_will(TELOPT_STATUS, 1);
flowmode = 1; /* default flow control state */
send_do(TELOPT_LFLOW, 1);
/*
* Spin, waiting for a response from the DO ECHO. However,
* some REALLY DUMB telnets out there might not respond
* to the DO ECHO. So, we spin looking for NAWS, (most dumb
* telnets so far seem to respond with WONT for a DO that
* they don't understand...) because by the time we get the
* response, it will already have processed the DO ECHO.
* Kludge upon kludge.
*/
while (his_will_wont_is_changing(TELOPT_NAWS)) {
ttloop();
}
/*
* But...
* The client might have sent a WILL NAWS as part of its
* startup code; if so, we'll be here before we get the
* response to the DO ECHO. We'll make the assumption
* that any implementation that understands about NAWS
* is a modern enough implementation that it will respond
* to our DO ECHO request; hence we'll do another spin
* waiting for the ECHO option to settle down, which is
* what we wanted to do in the first place...
*/
if (his_want_state_is_will(TELOPT_ECHO) &&
his_state_is_will(TELOPT_NAWS)) {
while (his_will_wont_is_changing(TELOPT_ECHO))
ttloop();
}
/*
* On the off chance that the telnet client is broken and does not
* respond to the DO ECHO we sent, (after all, we did send the
* DO NAWS negotiation after the DO ECHO, and we won't get here
* until a response to the DO NAWS comes back) simulate the
* receipt of a will echo. This will also send a WONT ECHO
* to the client, since we assume that the client failed to
* respond because it believes that it is already in DO ECHO
* mode, which we do not want.
*/
if (his_want_state_is_will(TELOPT_ECHO)) {
DIAG(TD_OPTIONS, netoprintf("td: simulating recv\r\n"););
willoption(TELOPT_ECHO);
}