new telnet code.

This commit is contained in:
Kelvin Sherlock 2018-04-21 16:14:14 -04:00
parent c956be1319
commit 1380609800

264
telnet.c Normal file
View File

@ -0,0 +1,264 @@
/*
* This handles telnet "negotiation", etc.
* We don't actually negotiate anything but we at least strip
* the telnet commands.
*/
#pragma noroot
#include "telnet.h"
extern unsigned char buffer[];
extern unsigned buffer_size;
extern void send(const unsigned char *, unsigned);
enum {
st_data = 0,
st_iac,
st_do,
st_dont,
st_will,
st_wont,
st_sb,
st_sb_iac,
st_cr
};
static int state = 0;
static unsigned do_bits[3];
static unsigned dont_bits[3];
static unsigned will_bits[3];
static unsigned wont_bits[3];
#define set_bit(type, x) \
type ## _bits[(x) >> 4] |= 1 << ((x) & 0x0f)
#define has_bit(type, x) \
(type ## _bits[(x) >> 4] & 1 << ((x) & 0x0f))
void telnet_init(void) {
static unsigned char msg[] = {
IAC, DO, TELOPT_SGA,
IAC, DO, TELOPT_ECHO,
IAC, WONT, TELOPT_ECHO,
IAC, DO, TELOPT_BINARY,
IAC, DONT, TELOPT_LINEMODE,
IAC, WILL, TELOPT_TTYPE,
IAC, WILL, TELOPT_NAWS,
IAC, WILL, TELOPT_TSPEED,
};
do_bits[0] = 0;
do_bits[1] = 0;
do_bits[2] = 0;
dont_bits[0] = 0;
dont_bits[1] = 0;
dont_bits[2] = 0;
will_bits[0] = 0;
will_bits[1] = 0;
will_bits[2] = 0;
wont_bits[0] = 0;
wont_bits[1] = 0;
wont_bits[2] = 0;
state = st_data;
#if 0
set_bit(do, TELOPT_SGA);
set_bit(do, TELOPT_ECHO);
set_bit(do, TELOPT_BINARY);
set_bit(dont, TELOPT_LINEMODE);
set_bit(will, TELOPT_TTYPE);
set_bit(will, TELOPT_NAWS);
set_bit(will, TELOPT_TSPEED);
#endif
send(msg, sizeof(msg));
}
void telnet_process(void) {
unsigned i, j;
unsigned char cmd[3];
static unsigned char telopt_naws[] = {
IAC, SB, TELOPT_NAWS,
0, 80, 0, 24,
IAC, SE
};
static unsigned char telopt_tspeed[] = {
IAC, SB, TELOPT_TSPEED,
'9', '6', '0', '0', ',', '9', '6', '0', '0',
IAC, SE
};
static unsigned char telopt_ttype[] = {
IAC, SB, TELOPT_TTYPE, TELQUAL_IS,
'V', 'T', '1', '0', '0',
IAC, SE
};
/* don't need to process if no state, no IACs in buffer */
if (!state) {
/* check for an IAC */
for (i = 0; i < buffer_size; ++i) {
if (buffer[i] == IAC) break;
}
if (i == buffer_size) return;
}
for (i = 0, j = 0; i < buffer_size; ++i) {
unsigned char c = buffer[i];
switch(state) {
#if 0
// ignoring this for now since vt100 ignores 0x00 anyhow.
// also, would only run if other IAC detected.
case st_cr: // 0x0d 0x00 < drop the 0x00
if (c == 0x00) {
state = st_data;
break;
}
/* drop through */
#endif
case st_data:
if (c == IAC) {
state = st_iac;
}
else buffer[j++] = c;
//if (c == 0x0d) state = st_cr;
break;
case st_iac:
switch (c) {
case IAC: // IAC IAC -> IAC
state = st_data;
buffer[j++] = c;
break;
case AYT:
send("\r\n[Yes]\r\n", 9);
state = st_data;
break;
case DO: state = st_do; break;
case DONT: state = st_dont; break;
case WILL: state = st_will; break;
case WONT: state = st_wont; break;
case SB: state = st_sb; break;
default: state = st_data; break;
}
break;
case st_do:
cmd[0] = IAC;
cmd[1] = WILL;
cmd[2] = c;
switch(c) {
case TELOPT_SGA:
case TELOPT_BINARY:
// already said will do them, no reply needed.
break;
case TELOPT_NAWS:
set_bit(do, TELOPT_NAWS);
send(telopt_naws, sizeof(telopt_naws));
break;
case TELOPT_TSPEED:
send(telopt_tspeed, sizeof(telopt_tspeed));
break;
case TELOPT_TTYPE:
send(telopt_ttype, sizeof(telopt_ttype));
break;
default:
case TELOPT_ECHO:
cmd[1] = WONT;
send(cmd, 3);
}
state = st_data;
break;
case st_dont:
cmd[0] = IAC;
cmd[1] = WONT;
cmd[2] = c;
#if 0
switch(c) {
case TELOPT_SGA:
cmd[1] = WILL;
break;
default:
}
#endif
send(cmd, 3);
state = st_data;
break;
case st_will:
cmd[0] = IAC;
cmd[1] = DO;
cmd[2] = c;
switch(c) {
case TELOPT_SGA:
case TELOPT_BINARY:
case TELOPT_ECHO:
case TELOPT_NAWS:
break;
default:
cmd[1] = DONT;
send(cmd, 3);
}
state = st_data;
break;
case st_wont:
#if 0
cmd[0] = IAC;
cmd[1] = DONT;
cmd[2] = c;
switch(c) {
case TELOPT_SGA:
case TELOPT_LINEMODE:
cmp[1] = DO;
break;
default:
}
send(cmd, 3);
#endif
state = st_data;
break;
case st_sb:
if (c == IAC) state = st_sb_iac;
break;
case st_sb_iac:
// IAC | IAC or IAC | SE
if (c == SE) state = st_data;
else state = st_sb;
break;
}
}
buffer_size = j;
}