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#include "bbs.h"
static TelnetCtx telnet_ctx;
static char raw_connection = 0;
#ifdef DETECT_CLIENT
extern void UpdateClientCode(unsigned char c);
static void
telnet_cb_update_client_code(void *cc_arg, unsigned char c)
{
UpdateClientCode(c);
}
#endif
static void
telnet_cb_resize_term(void *resize_arg, int w, int h)
{
term_resize(w, h);
}
const static struct TelnetCallback telnet_callback = {
NULL,
telnet_cb_resize_term,
#ifdef DETECT_CLIENT
telnet_cb_update_client_code,
#else
NULL,
#endif
};
void
telnet_init(int do_init_cmd)
{
int fd = 0;
TelnetCtx *ctx = &telnet_ctx;
raw_connection = 1;
telnet_ctx_init(ctx, &telnet_callback, fd);
#ifdef DETECT_CLIENT
telnet_ctx_set_cc_arg(ctx, (void*)1);
#endif
if (do_init_cmd)
telnet_ctx_send_init_cmds(ctx);
}
#if defined(DBCSAWARE) && !defined(DBCSAWARE_SKIP_EVIL_REPEATS_CHECK)
ssize_t
dbcs_detect_evil_repeats(unsigned char *buf, ssize_t l)
{
// determine DBCS repeats by evil clients (ref: io.c)
if (l == 2)
{
// XXX l=2 is dangerous. hope we are not in telnet IAC state...
// BS: \b
// BS2: \x7f
// DEL2: Ctrl('D') (KKMan3 also treats Ctrl('D') as DBCS DEL)
if (buf[0] != buf[1])
return l;
// Note: BS/DEL behavior on different clients:
// screen/telnet:BS=0x7F, DEL=^[3~
// PCMan2004: BS=0x7F, DEL=^[3~
// KKMan3: BS=0x1b, DEL=0x7F
// WinXP telnet: BS=0x1b, DEL=0x7F
if (buf[0] == '\b' ||
buf[0] == '\x7f' ||
buf[0] == Ctrl('D'))
return l-1;
}
else if (l == 6)
{
// RIGHT: ESC_CHR "OC" or ESC_CHR "[C"
// LEFT: ESC_CHR "OD" or ESC_CHR "[D"
if (buf[2] != 'C' && buf[2] != 'D')
return l;
if ( buf[0] == ESC_CHR &&
(buf[1] == '[' || buf[1] == 'O') &&
buf[0] == buf[3] &&
buf[1] == buf[4] &&
buf[2] == buf[5])
return l-3;
}
else if (l == 8)
{
// RIGHT: ESC_CHR "[OC"
// LEFT: ESC_CHR "[OD"
// DEL: ESC_STR "[3~" // vt220
if (buf[2] != '3' && buf[2] != 'O')
return l;
if (buf[0] != ESC_CHR ||
buf[1] != '[' ||
buf[4] != buf[0] ||
buf[5] != buf[1] ||
buf[6] != buf[2] ||
buf[7] != buf[3])
return l;
if (buf[2] == '3' &&
buf[3] == '~')
return l-4;
if ( buf[2] == 'O' &&
(buf[3] == 'C' || buf[3] == 'D') )
return l-4;
}
return l;
}
#endif
/* tty_read
* read from tty, process telnet commands if raw connection.
* return: >0 = length, <=0 means read more, abort/eof is automatically processed.
*/
ssize_t
tty_read(unsigned char *buf, size_t max)
{
ssize_t l = read(0, buf, max);
TelnetCtx *ctx = &telnet_ctx;
if(l == 0 || (l < 0 && !(errno == EINTR || errno == EAGAIN)))
abort_bbs(0);
#if defined(DBCSAWARE) && !defined(DBCSAWARE_SKIP_EVIL_REPEATS_CHECK)
if (ISDBCSAWARE())
l = dbcs_detect_evil_repeats(buf, l);
#endif
if(!raw_connection || l <= 0)
return l;
l = telnet_process(ctx, buf, l);
return l;
}
void
telnet_turnoff_client_detect(void)
{
TelnetCtx *ctx = &telnet_ctx;
telnet_ctx_set_cc_arg(ctx, NULL);
}
// vim: sw=4
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