static void handlenetinput(int len)
{
int i;
int cstart = 0;
for (i = 0; i < len; i++)
{
byte c = G.buf[i];
if (G.telstate == 0) /* most of the time state == 0 */
{
if (c == IAC)
{
cstart = i;
G.telstate = TS_IAC;
}
}
else
switch (G.telstate)
{
case TS_0:
if (c == IAC)
G.telstate = TS_IAC;
else
G.buf[cstart++] = c;
break;
case TS_IAC:
if (c == IAC) /* IAC IAC -> 0xFF */
{
G.buf[cstart++] = c;
G.telstate = TS_0;
break;
}
/* else */
switch (c)
{
case SB:
G.telstate = TS_SUB1;
break;
case DO:
case DONT:
case WILL:
case WONT:
G.telwish = c;
G.telstate = TS_OPT;
break;
default:
G.telstate = TS_0; /* DATA MARK must be added later */
}
break;
case TS_OPT: /* WILL, WONT, DO, DONT */
telopt(c);
G.telstate = TS_0;
break;
case TS_SUB1: /* Subnegotiation */
case TS_SUB2: /* Subnegotiation */
if (subneg(c))
G.telstate = TS_0;
break;
}
}
if (G.telstate)
{
if (G.iaclen) iacflush();
if (G.telstate == TS_0) G.telstate = 0;
len = cstart;
}
if (len)
write(1, G.buf, len);
}
static void handle_net_input(int len)
{
int i;
int cstart = 0;
for (i = 0; i < len; i++) {
byte c = G.buf[i];
if (G.telstate == TS_NORMAL) { /* most typical state */
if (c == IAC) {
cstart = i;
G.telstate = TS_IAC;
}
else if (c == '\r') {
cstart = i + 1;
G.telstate = TS_CR;
}
/* No IACs were seen so far, no need to copy
* bytes within G.buf: */
continue;
}
switch (G.telstate) {
case TS_CR:
/* Prev char was CR. If cur one is NUL, ignore it.
* See RFC 1123 section 3.3.1 for discussion of telnet EOL handling.
*/
G.telstate = TS_COPY;
if (c == '\0')
break;
/* else: fall through - need to handle CR IAC ... properly */
case TS_COPY: /* Prev char was ordinary */
/* Similar to NORMAL, but in TS_COPY we need to copy bytes */
if (c == IAC)
G.telstate = TS_IAC;
else
G.buf[cstart++] = c;
if (c == '\r')
G.telstate = TS_CR;
break;
case TS_IAC: /* Prev char was IAC */
if (c == IAC) { /* IAC IAC -> one IAC */
G.buf[cstart++] = c;
G.telstate = TS_COPY;
break;
}
/* else */
switch (c) {
case SB:
G.telstate = TS_SUB1;
break;
case DO:
case DONT:
case WILL:
case WONT:
G.telwish = c;
G.telstate = TS_OPT;
break;
/* DATA MARK must be added later */
default:
G.telstate = TS_COPY;
}
break;
case TS_OPT: /* Prev chars were IAC WILL/WONT/DO/DONT */
telopt(c);
G.telstate = TS_COPY;
break;
case TS_SUB1: /* Subnegotiation */
case TS_SUB2: /* Subnegotiation */
subneg(c); /* can change G.telstate */
break;
}
}
if (G.telstate != TS_NORMAL) {
/* We had some IACs, or CR */
if (G.iaclen)
iac_flush();
if (G.telstate == TS_COPY) /* we aren't in the middle of IAC */
G.telstate = TS_NORMAL;
len = cstart;
}
if (len)
full_write(STDOUT_FILENO, G.buf, len);
}
