void
printoption(const char *direction, int cmd, int option)
{
if (!showoptions)
return;
if (cmd == IAC) {
if (TELCMD_OK(option))
fprintf(NetTrace, "%s IAC %s", direction, TELCMD(option));
else
fprintf(NetTrace, "%s IAC %d", direction, option);
} else {
const char *fmt;
fmt = (cmd == WILL) ? "WILL" : (cmd == WONT) ? "WONT" :
(cmd == DO) ? "DO" : (cmd == DONT) ? "DONT" : 0;
if (fmt) {
fprintf(NetTrace, "%s %s ", direction, fmt);
if (TELOPT_OK(option))
fprintf(NetTrace, "%s", TELOPT(option));
else if (option == TELOPT_EXOPL)
fprintf(NetTrace, "EXOPL");
else
fprintf(NetTrace, "%d", option);
} else
fprintf(NetTrace, "%s %d %d", direction, cmd, option);
}
if (NetTrace == stdout) {
fprintf(NetTrace, "\r\n");
fflush(NetTrace);
} else {
fprintf(NetTrace, "\n");
}
return;
}
/* int length; length of suboption data */
void
printsub (char direction, unsigned char *pointer, int length)
{
register int i;
extern int want_status_response;
#if defined AUTHENTICATION || defined ENCRYPTION
char buf[512];
#endif
if (showoptions || direction == 0 ||
(want_status_response && (pointer[0] == TELOPT_STATUS)))
{
if (direction)
{
fprintf (NetTrace, "%s IAC SB ",
(direction == '<') ? "RCVD" : "SENT");
if (length >= 3)
{
register int j;
i = pointer[length - 2];
j = pointer[length - 1];
if (i != IAC || j != SE)
{
fprintf (NetTrace, "(terminated by ");
if (TELOPT_OK (i))
fprintf (NetTrace, "%s ", TELOPT (i));
else if (TELCMD_OK (i))
fprintf (NetTrace, "%s ", TELCMD (i));
else
fprintf (NetTrace, "%d ", i);
if (TELOPT_OK (j))
fprintf (NetTrace, "%s", TELOPT (j));
else if (TELCMD_OK (j))
fprintf (NetTrace, "%s", TELCMD (j));
else
fprintf (NetTrace, "%d", j);
fprintf (NetTrace, ", not IAC SE!) ");
}
}
length -= 2;
}
if (length < 1)
{
fprintf (NetTrace, "(Empty suboption??\?)");
if (NetTrace == stdout)
fflush (NetTrace);
return;
}
switch (pointer[0])
{
case TELOPT_TTYPE:
fprintf (NetTrace, "TERMINAL-TYPE ");
switch (pointer[1])
{
case TELQUAL_IS:
fprintf (NetTrace, "IS \"%.*s\"", length - 2,
(char *) pointer + 2);
break;
case TELQUAL_SEND:
fprintf (NetTrace, "SEND");
break;
default:
fprintf (NetTrace, "- unknown qualifier %d (0x%x).",
pointer[1], pointer[1]);
}
break;
case TELOPT_TSPEED:
fprintf (NetTrace, "TERMINAL-SPEED");
if (length < 2)
{
fprintf (NetTrace, " (empty suboption??\?)");
break;
}
switch (pointer[1])
{
case TELQUAL_IS:
fprintf (NetTrace, " IS ");
fprintf (NetTrace, "%.*s", length - 2, (char *) pointer + 2);
break;
default:
if (pointer[1] == 1)
fprintf (NetTrace, " SEND");
else
fprintf (NetTrace, " %d (unknown)", pointer[1]);
for (i = 2; i < length; i++)
fprintf (NetTrace, " ?%d?", pointer[i]);
break;
}
break;
case TELOPT_LFLOW:
fprintf (NetTrace, "TOGGLE-FLOW-CONTROL");
if (length < 2)
{
fprintf (NetTrace, " (empty suboption??\?)");
break;
}
switch (pointer[1])
{
case LFLOW_OFF:
fprintf (NetTrace, " OFF");
break;
case LFLOW_ON:
fprintf (NetTrace, " ON");
break;
case LFLOW_RESTART_ANY:
fprintf (NetTrace, " RESTART-ANY");
break;
case LFLOW_RESTART_XON:
fprintf (NetTrace, " RESTART-XON");
break;
default:
fprintf (NetTrace, " %d (unknown)", pointer[1]);
}
for (i = 2; i < length; i++)
fprintf (NetTrace, " ?%d?", pointer[i]);
break;
case TELOPT_NAWS:
fprintf (NetTrace, "NAWS");
if (length < 2)
{
fprintf (NetTrace, " (empty suboption??\?)");
break;
}
if (length == 2)
{
fprintf (NetTrace, " ?%d?", pointer[1]);
break;
}
fprintf (NetTrace, " %d %d (%d)",
pointer[1], pointer[2],
(int) ((((unsigned int) pointer[1]) << 8) |
((unsigned int) pointer[2])));
if (length == 4)
{
fprintf (NetTrace, " ?%d?", pointer[3]);
break;
}
fprintf (NetTrace, " %d %d (%d)",
pointer[3], pointer[4],
(int) ((((unsigned int) pointer[3]) << 8) |
((unsigned int) pointer[4])));
for (i = 5; i < length; i++)
fprintf (NetTrace, " ?%d?", pointer[i]);
break;
#if defined AUTHENTICATION
case TELOPT_AUTHENTICATION:
fprintf (NetTrace, "AUTHENTICATION");
if (length < 2)
{
fprintf (NetTrace, " (empty suboption??\?)");
break;
}
switch (pointer[1])
{
case TELQUAL_REPLY:
case TELQUAL_IS:
fprintf (NetTrace, " %s ",
(pointer[1] == TELQUAL_IS) ? "IS" : "REPLY");
if (AUTHTYPE_NAME_OK (pointer[2]) && AUTHTYPE_NAME (pointer[2]))
fprintf (NetTrace, "%s ", AUTHTYPE_NAME (pointer[2]));
else
fprintf (NetTrace, "%d ", pointer[2]);
if (length < 3)
{
fprintf (NetTrace, "(partial suboption??\?)");
break;
}
fprintf (NetTrace, "%s|%s",
((pointer[3] & AUTH_WHO_MASK) == AUTH_WHO_CLIENT)
? "CLIENT" : "SERVER",
((pointer[3] & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL)
? "MUTUAL" : "ONE-WAY");
auth_printsub (&pointer[1], length - 1, buf, sizeof (buf));
fprintf (NetTrace, "%s", buf);
break;
case TELQUAL_SEND:
i = 2;
fprintf (NetTrace, " SEND ");
while (i < length)
{
if (AUTHTYPE_NAME_OK (pointer[i])
&& AUTHTYPE_NAME (pointer[i]))
fprintf (NetTrace, "%s ", AUTHTYPE_NAME (pointer[i]));
else
fprintf (NetTrace, "%d ", pointer[i]);
if (++i >= length)
{
fprintf (NetTrace, "(partial suboption??\?)");
break;
}
fprintf (NetTrace, "%s|%s ",
((pointer[i] & AUTH_WHO_MASK) == AUTH_WHO_CLIENT)
? "CLIENT" : "SERVER",
((pointer[i] & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL)
? "MUTUAL" : "ONE-WAY");
++i;
}
break;
case TELQUAL_NAME:
i = 2;
fprintf (NetTrace, " NAME \"");
while (i < length)
putc (pointer[i++], NetTrace);
putc ('"', NetTrace);
break;
default:
for (i = 2; i < length; i++)
fprintf (NetTrace, " ?%d?", pointer[i]);
break;
}
break;
#endif
#ifdef ENCRYPTION
case TELOPT_ENCRYPT:
fprintf (NetTrace, "ENCRYPT");
if (length < 2)
{
fprintf (NetTrace, " (empty suboption??\?)");
break;
}
switch (pointer[1])
{
case ENCRYPT_START:
fprintf (NetTrace, " START");
break;
case ENCRYPT_END:
fprintf (NetTrace, " END");
break;
case ENCRYPT_REQSTART:
fprintf (NetTrace, " REQUEST-START");
break;
case ENCRYPT_REQEND:
fprintf (NetTrace, " REQUEST-END");
break;
case ENCRYPT_IS:
case ENCRYPT_REPLY:
fprintf (NetTrace, " %s ",
(pointer[1] == ENCRYPT_IS) ? "IS" : "REPLY");
if (length < 3)
{
fprintf (NetTrace, " (partial suboption??\?)");
break;
}
if (ENCTYPE_NAME_OK (pointer[2]) && ENCTYPE_NAME (pointer[2]))
fprintf (NetTrace, "%s ", ENCTYPE_NAME (pointer[2]));
else
fprintf (NetTrace, " %d (unknown)", pointer[2]);
encrypt_printsub (&pointer[1], length - 1, buf, sizeof (buf));
fprintf (NetTrace, "%s", buf);
break;
case ENCRYPT_SUPPORT:
i = 2;
fprintf (NetTrace, " SUPPORT ");
while (i < length)
{
if (ENCTYPE_NAME_OK (pointer[i]) && ENCTYPE_NAME (pointer[i]))
fprintf (NetTrace, "%s ", ENCTYPE_NAME (pointer[i]));
else
fprintf (NetTrace, "%d ", pointer[i]);
i++;
}
break;
case ENCRYPT_ENC_KEYID:
fprintf (NetTrace, " ENC_KEYID ");
goto encommon;
case ENCRYPT_DEC_KEYID:
fprintf (NetTrace, " DEC_KEYID ");
goto encommon;
default:
fprintf (NetTrace, " %d (unknown)", pointer[1]);
encommon:
for (i = 2; i < length; i++)
fprintf (NetTrace, " %d", pointer[i]);
break;
}
break;
#endif /* ENCRYPTION */
case TELOPT_LINEMODE:
fprintf (NetTrace, "LINEMODE ");
if (length < 2)
{
fprintf (NetTrace, " (empty suboption??\?)");
break;
}
switch (pointer[1])
{
case WILL:
fprintf (NetTrace, "WILL ");
goto common;
case WONT:
fprintf (NetTrace, "WONT ");
goto common;
case DO:
fprintf (NetTrace, "DO ");
goto common;
case DONT:
fprintf (NetTrace, "DONT ");
common:
if (length < 3)
{
fprintf (NetTrace, "(no option??\?)");
break;
}
switch (pointer[2])
{
case LM_FORWARDMASK:
fprintf (NetTrace, "Forward Mask");
for (i = 3; i < length; i++)
fprintf (NetTrace, " %x", pointer[i]);
break;
default:
fprintf (NetTrace, "%d (unknown)", pointer[2]);
for (i = 3; i < length; i++)
fprintf (NetTrace, " %d", pointer[i]);
break;
}
break;
case LM_SLC:
fprintf (NetTrace, "SLC");
for (i = 2; i < length - 2; i += 3)
{
if (SLC_NAME_OK (pointer[i + SLC_FUNC]))
fprintf (NetTrace, " %s",
SLC_NAME (pointer[i + SLC_FUNC]));
else
fprintf (NetTrace, " %d", pointer[i + SLC_FUNC]);
switch (pointer[i + SLC_FLAGS] & SLC_LEVELBITS)
{
case SLC_NOSUPPORT:
fprintf (NetTrace, " NOSUPPORT");
break;
case SLC_CANTCHANGE:
fprintf (NetTrace, " CANTCHANGE");
break;
case SLC_VARIABLE:
fprintf (NetTrace, " VARIABLE");
break;
case SLC_DEFAULT:
fprintf (NetTrace, " DEFAULT");
break;
}
fprintf (NetTrace, "%s%s%s",
(pointer[i + SLC_FLAGS] & SLC_ACK)
? "|ACK" : "",
(pointer[i + SLC_FLAGS] & SLC_FLUSHIN)
? "|FLUSHIN" : "",
(pointer[i + SLC_FLAGS] & SLC_FLUSHOUT)
? "|FLUSHOUT" : "");
if (pointer[i + SLC_FLAGS] &
~(SLC_ACK | SLC_FLUSHIN | SLC_FLUSHOUT | SLC_LEVELBITS))
fprintf (NetTrace, "(0x%x)", pointer[i + SLC_FLAGS]);
fprintf (NetTrace, " %d;", pointer[i + SLC_VALUE]);
if ((pointer[i + SLC_VALUE] == IAC) &&
(pointer[i + SLC_VALUE + 1] == IAC))
i++;
}
for (; i < length; i++)
fprintf (NetTrace, " ?%d?", pointer[i]);
break;
case LM_MODE:
fprintf (NetTrace, "MODE ");
if (length < 3)
{
fprintf (NetTrace, "(no mode??\?)");
break;
}
{
char tbuf[64];
sprintf (tbuf, "%s%s%s%s%s",
pointer[2] & MODE_EDIT ? "|EDIT" : "",
pointer[2] & MODE_TRAPSIG ? "|TRAPSIG" : "",
pointer[2] & MODE_SOFT_TAB ? "|SOFT_TAB" : "",
pointer[2] & MODE_LIT_ECHO ? "|LIT_ECHO" : "",
pointer[2] & MODE_ACK ? "|ACK" : "");
fprintf (NetTrace, "%s", tbuf[1] ? &tbuf[1] : "0");
}
if (pointer[2] & ~(MODE_MASK))
fprintf (NetTrace, " (0x%x)", pointer[2]);
for (i = 3; i < length; i++)
fprintf (NetTrace, " ?0x%x?", pointer[i]);
break;
default:
fprintf (NetTrace, "%d (unknown)", pointer[1]);
for (i = 2; i < length; i++)
fprintf (NetTrace, " %d", pointer[i]);
}
break;
case TELOPT_STATUS:
{
register char *cp;
register int j, k;
fprintf (NetTrace, "STATUS");
switch (pointer[1])
{
default:
if (pointer[1] == TELQUAL_SEND)
fprintf (NetTrace, " SEND");
else
fprintf (NetTrace, " %d (unknown)", pointer[1]);
for (i = 2; i < length; i++)
fprintf (NetTrace, " ?%d?", pointer[i]);
break;
case TELQUAL_IS:
if (--want_status_response < 0)
want_status_response = 0;
if (NetTrace == stdout)
fprintf (NetTrace, " IS\r\n");
else
fprintf (NetTrace, " IS\n");
for (i = 2; i < length; i++)
{
switch (pointer[i])
{
case DO:
cp = "DO";
goto common2;
case DONT:
cp = "DONT";
goto common2;
case WILL:
cp = "WILL";
goto common2;
case WONT:
cp = "WONT";
goto common2;
common2:
i++;
if (TELOPT_OK ((int) pointer[i]))
fprintf (NetTrace, " %s %s", cp,
TELOPT (pointer[i]));
else
fprintf (NetTrace, " %s %d", cp, pointer[i]);
if (NetTrace == stdout)
fprintf (NetTrace, "\r\n");
else
fprintf (NetTrace, "\n");
break;
case SB:
fprintf (NetTrace, " SB ");
i++;
j = k = i;
while (j < length)
{
if (pointer[j] == SE)
{
if (j + 1 == length)
break;
if (pointer[j + 1] == SE)
j++;
else
break;
}
pointer[k++] = pointer[j++];
}
printsub (0, &pointer[i], k - i);
if (i < length)
{
fprintf (NetTrace, " SE");
i = j;
}
else
i = j - 1;
if (NetTrace == stdout)
fprintf (NetTrace, "\r\n");
else
fprintf (NetTrace, "\n");
break;
default:
fprintf (NetTrace, " %d", pointer[i]);
break;
}
}
break;
}
break;
}
case TELOPT_XDISPLOC:
fprintf (NetTrace, "X-DISPLAY-LOCATION ");
switch (pointer[1])
{
case TELQUAL_IS:
fprintf (NetTrace, "IS \"%.*s\"", length - 2,
(char *) pointer + 2);
break;
case TELQUAL_SEND:
fprintf (NetTrace, "SEND");
break;
default:
fprintf (NetTrace, "- unknown qualifier %d (0x%x).",
pointer[1], pointer[1]);
}
break;
case TELOPT_NEW_ENVIRON:
fprintf (NetTrace, "NEW-ENVIRON ");
#ifdef OLD_ENVIRON
goto env_common1;
case TELOPT_OLD_ENVIRON:
fprintf (NetTrace, "OLD-ENVIRON");
env_common1:
#endif
switch (pointer[1])
{
case TELQUAL_IS:
fprintf (NetTrace, "IS ");
goto env_common;
case TELQUAL_SEND:
fprintf (NetTrace, "SEND ");
goto env_common;
case TELQUAL_INFO:
fprintf (NetTrace, "INFO ");
env_common:
{
const char *quote = "";
#if defined ENV_HACK && defined OLD_ENVIRON
extern int old_env_var, old_env_value;
#endif
for (i = 2; i < length; i++)
{
switch (pointer[i])
{
case NEW_ENV_VALUE:
#ifdef OLD_ENVIRON
/* case NEW_ENV_OVAR: */
if (pointer[0] == TELOPT_OLD_ENVIRON)
{
# ifdef ENV_HACK
if (old_env_var == OLD_ENV_VALUE)
fprintf (NetTrace, "%s(VALUE) ", quote);
else
# endif
fprintf (NetTrace, "%sVAR ", quote);
}
else
#endif /* OLD_ENVIRON */
fprintf (NetTrace, "%sVALUE ", quote);
quote = "";
break;
case NEW_ENV_VAR:
#ifdef OLD_ENVIRON
/* case OLD_ENV_VALUE: */
if (pointer[0] == TELOPT_OLD_ENVIRON)
{
# ifdef ENV_HACK
if (old_env_value == OLD_ENV_VAR)
fprintf (NetTrace, "%s(VAR) ", quote);
else
# endif
fprintf (NetTrace, "%sVALUE ", quote);
}
else
#endif /* OLD_ENVIRON */
fprintf (NetTrace, "%sVAR ", quote);
quote = "";
break;
case ENV_ESC:
fprintf (NetTrace, "%sESC ", quote);
quote = "";
break;
case ENV_USERVAR:
fprintf (NetTrace, "%sUSERVAR ", quote);
quote = "";
break;
default:
if (isprint (pointer[i]) && pointer[i] != '"')
{
if (quote[0] == '\0')
{
putc ('"', NetTrace);
quote = "\" ";
}
putc (pointer[i], NetTrace);
}
else
{
fprintf (NetTrace, "%s%03o ", quote, pointer[i]);
quote = "";
}
break;
}
}
if (quote[0] != '\0')
putc ('"', NetTrace);
break;
}
}
break;
default:
if (TELOPT_OK (pointer[0]))
fprintf (NetTrace, "%s (unknown)", TELOPT (pointer[0]));
else
fprintf (NetTrace, "%d (unknown)", pointer[0]);
for (i = 1; i < length; i++)
fprintf (NetTrace, " %d", pointer[i]);
break;
}
if (direction)
{
if (NetTrace == stdout)
fprintf (NetTrace, "\r\n");
else
fprintf (NetTrace, "\n");
}
if (NetTrace == stdout)
fflush (NetTrace);
}
}
void
optionstatus (void)
{
register int i;
extern char will_wont_resp[], do_dont_resp[];
for (i = 0; i < 256; i++)
{
if (do_dont_resp[i])
{
if (TELOPT_OK (i))
printf ("resp DO_DONT %s: %d\n", TELOPT (i), do_dont_resp[i]);
else if (TELCMD_OK (i))
printf ("resp DO_DONT %s: %d\n", TELCMD (i), do_dont_resp[i]);
else
printf ("resp DO_DONT %d: %d\n", i, do_dont_resp[i]);
if (my_want_state_is_do (i))
{
if (TELOPT_OK (i))
printf ("want DO %s\n", TELOPT (i));
else if (TELCMD_OK (i))
printf ("want DO %s\n", TELCMD (i));
else
printf ("want DO %d\n", i);
}
else
{
if (TELOPT_OK (i))
printf ("want DONT %s\n", TELOPT (i));
else if (TELCMD_OK (i))
printf ("want DONT %s\n", TELCMD (i));
else
printf ("want DONT %d\n", i);
}
}
else
{
if (my_state_is_do (i))
{
if (TELOPT_OK (i))
printf (" DO %s\n", TELOPT (i));
else if (TELCMD_OK (i))
printf (" DO %s\n", TELCMD (i));
else
printf (" DO %d\n", i);
}
}
if (will_wont_resp[i])
{
if (TELOPT_OK (i))
printf ("resp WILL_WONT %s: %d\n", TELOPT (i), will_wont_resp[i]);
else if (TELCMD_OK (i))
printf ("resp WILL_WONT %s: %d\n", TELCMD (i), will_wont_resp[i]);
else
printf ("resp WILL_WONT %d: %d\n", i, will_wont_resp[i]);
if (my_want_state_is_will (i))
{
if (TELOPT_OK (i))
printf ("want WILL %s\n", TELOPT (i));
else if (TELCMD_OK (i))
printf ("want WILL %s\n", TELCMD (i));
else
printf ("want WILL %d\n", i);
}
else
{
if (TELOPT_OK (i))
printf ("want WONT %s\n", TELOPT (i));
else if (TELCMD_OK (i))
printf ("want WONT %s\n", TELCMD (i));
else
printf ("want WONT %d\n", i);
}
}
else
{
if (my_state_is_will (i))
{
if (TELOPT_OK (i))
printf (" WILL %s\n", TELOPT (i));
else if (TELCMD_OK (i))
printf (" WILL %s\n", TELCMD (i));
else
printf (" WILL %d\n", i);
}
}
}
}
/* input: raw character
* output: telnet command if c was handled, otherwise zero.
*/
unsigned int
telnet_handler(unsigned char c)
{
static unsigned char iac_quote = 0; /* as byte to reduce memory */
static unsigned char iac_opt_req = 0;
static unsigned char iac_buf[TELNET_IAC_MAXLEN];
static unsigned int iac_buflen = 0;
/* we have to quote all IACs. */
if(c == IAC && !iac_quote) {
iac_quote = 1;
return NOP;
}
#ifdef DETECT_CLIENT
/* hash client telnet sequences */
if(cuser.userid[0]==0) {
if(iac_state == IAC_WAIT_SE) {
// skip suboption
} else {
if(iac_quote)
UpdateClientCode(IAC);
UpdateClientCode(c);
}
}
#endif
/* a special case is the top level iac. otherwise, iac is just a quote. */
if (iac_quote) {
if(iac_state == IAC_NONE)
iac_state = IAC_COMMAND;
if(iac_state == IAC_WAIT_SE && c == SE)
iac_state = IAC_PROCESS_OPT;
iac_quote = 0;
}
/* now, let's process commands by state */
switch(iac_state) {
case IAC_NONE:
return 0;
case IAC_COMMAND:
#if 0 // def DEBUG
{
int cx = c; /* to make compiler happy */
write(0, "-", 1);
if(TELCMD_OK(cx))
write(0, TELCMD(c), strlen(TELCMD(c)));
write(0, " ", 1);
}
#endif
iac_state = IAC_NONE; /* by default we restore state. */
switch(c) {
case IAC:
// return 0;
// we don't want to allow IACs as input.
return 1;
/* we don't want to process these. or maybe in future. */
case BREAK: /* break */
#ifdef DBG_OUTRPT
fakeEscape = !fakeEscape;
return NOP;
#endif
case ABORT: /* Abort process */
case SUSP: /* Suspend process */
case AO: /* abort output--but let prog finish */
case IP: /* interrupt process--permanently */
case EOR: /* end of record (transparent mode) */
case DM: /* data mark--for connect. cleaning */
case xEOF: /* End of file: EOF is already used... */
return NOP;
case NOP: /* nop */
return NOP;
/* we should process these, but maybe in future. */
case GA: /* you may reverse the line */
case EL: /* erase the current line */
case EC: /* erase the current character */
return NOP;
/* good */
case AYT: /* are you there */
{
const char *alive = "I'm still alive, loading: ";
char buf[STRLEN];
/* respond as fast as we can */
write(0, alive, strlen(alive));
// cpuload(buf);
buf[0] = '0'; // TODO: cpuload
write(0, buf, strlen(buf));
write(0, "\r\n", 2);
}
return NOP;
case DONT: /* you are not to use option */
case DO: /* please, you use option */
case WONT: /* I won't use option */
case WILL: /* I will use option */
iac_opt_req = c;
iac_state = IAC_WAIT_OPT;
return NOP;
case SB: /* interpret as subnegotiation */
iac_state = IAC_WAIT_SE;
iac_buflen = 0;
return NOP;
case SE: /* end sub negotiation */
default:
return NOP;
}
return 1;
case IAC_WAIT_OPT:
#if 0 // def DEBUG
write(0, "-", 1);
if(TELOPT_OK(c))
write(0, TELOPT(c), strlen(TELOPT(c)));
write(0, " ", 1);
#endif
iac_state = IAC_NONE;
/*
* According to RFC, there're some tricky steps to prevent loop.
* However because we have a poor term which does not allow
* most abilities, let's be a strong boss here.
*
* Although my old imeplementation worked, it's even better to follow this:
* http://www.tcpipguide.com/free/t_TelnetOptionsandOptionNegotiation-3.htm
*/
switch(c) {
/* i-dont-care: i don't care about what client is.
* these should be clamed in init and
* client must follow me. */
case TELOPT_TTYPE: /* termtype or line. */
case TELOPT_NAWS: /* resize terminal */
case TELOPT_SGA: /* supress GA */
case TELOPT_ECHO: /* echo */
case TELOPT_BINARY: /* we are CJK. */
break;
/* i-dont-agree: i don't understand/agree these.
* according to RFC, saying NO stopped further
* requests so there'll not be endless loop. */
case TELOPT_RCP: /* prepare to reconnect */
default:
if (iac_opt_req == WILL || iac_opt_req == DO)
{
/* unknown option, reply with won't */
unsigned char cmd[3] = { IAC, DONT, 0 };
if(iac_opt_req == DO) cmd[1] = WONT;
cmd[2] = c;
write(0, cmd, sizeof(cmd));
}
break;
}
return 1;
case IAC_WAIT_SE:
iac_buf[iac_buflen++] = c;
/* no need to convert state because previous quoting will do. */
if(iac_buflen == TELNET_IAC_MAXLEN) {
/* may be broken protocol?
* whether finished or not, break for safety
* or user may be frozen.
*/
iac_state = IAC_NONE;
return 0;
}
return 1;
case IAC_PROCESS_OPT:
iac_state = IAC_NONE;
#if 0 // def DEBUG
write(0, "-", 1);
if(TELOPT_OK(iac_buf[0]))
write(0, TELOPT(iac_buf[0]), strlen(TELOPT(iac_buf[0])));
write(0, " ", 1);
#endif
switch(iac_buf[0]) {
/* resize terminal */
case TELOPT_NAWS:
{
int w = (iac_buf[1] << 8) + (iac_buf[2]);
int h = (iac_buf[3] << 8) + (iac_buf[4]);
term_resize(w, h);
#ifdef DETECT_CLIENT
if(cuser.userid[0]==0) {
UpdateClientCode(iac_buf[0]);
if(w==80 && h==24)
UpdateClientCode(1);
else if(w==80)
UpdateClientCode(2);
else if(h==24)
UpdateClientCode(3);
else
UpdateClientCode(4);
UpdateClientCode(IAC);
UpdateClientCode(SE);
}
#endif
}
break;
default:
#ifdef DETECT_CLIENT
if(cuser.userid[0]==0) {
int i;
for(i=0;i<iac_buflen;i++)
UpdateClientCode(iac_buf[i]);
UpdateClientCode(IAC);
UpdateClientCode(SE);
}
#endif
break;
}
return 1;
}
return 1; /* never reached */
}
