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libtelnet
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dont require a buffer for subnegotiations with no data; more efficient for apps that dont use more advanced subnegotiation features

This commit is contained in:
Sean Middleditch 2009-03-15 13:28:09 -04:00
parent 124a1c24f2
commit da0e695e62
3 changed files with 18 additions and 18 deletions
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2
README
View File

@ -20,13 +20,11 @@ code under copyright law.
- RFC 1143 option negotiation algorithm
- automatic MCCP2 handling (controllable by host app)
- efficient one-byte sub-requests
? MCCP1
? ZMP parsing
? MSSP parsing
? ENVIRON/NEW-ENVIRON parsing
? telnet-status testing tool
? few options to make telnet-proxy even more useful
I. INTRODUCTION
=====================================================================

29
libtelnet.c
View File

@ -263,11 +263,18 @@ static void _process(struct libtelnet_t *telnet, unsigned char *buffer,
telnet->state = LIBTELNET_STATE_DATA;
break;
/* subnegotiation -- buffer bytes until end request */
/* subnegotiation -- determine subnegotiation telopt */
case LIBTELNET_STATE_SB:
telnet->sb_telopt = byte;
telnet->length = 0;
telnet->state = LIBTELNET_STATE_SB_DATA;
break;
/* subnegotiation -- buffer bytes until end request */
case LIBTELNET_STATE_SB_DATA:
/* IAC command in subnegotiation -- either IAC SE or IAC IAC */
if (byte == LIBTELNET_IAC) {
telnet->state = LIBTELNET_STATE_SB_IAC;
telnet->state = LIBTELNET_STATE_SB_DATA_IAC;
/* buffer the byte, or bail if we can't */
} else if (_buffer_byte(telnet, byte, user_data) !=
LIBTELNET_EOK) {
@ -277,7 +284,7 @@ static void _process(struct libtelnet_t *telnet, unsigned char *buffer,
break;
/* IAC escaping inside a subnegotiation */
case LIBTELNET_STATE_SB_IAC:
case LIBTELNET_STATE_SB_DATA_IAC:
switch (byte) {
/* end subnegotiation */
case LIBTELNET_SE:
@ -285,25 +292,17 @@ static void _process(struct libtelnet_t *telnet, unsigned char *buffer,
start = i + 1;
telnet->state = LIBTELNET_STATE_DATA;
/* zero-size buffer is a protocol error */
if (telnet->length == 0) {
ERROR(telnet, LIBTELNET_EPROTOCOL, user_data,
"subnegotiation has zero data");
break;
}
/* invoke callback */
_event(telnet, LIBTELNET_EV_SUBNEGOTIATION, 0,
telnet->buffer[0], telnet->buffer + 1,
telnet->length - 1, user_data);
telnet->length = 0;
telnet->sb_telopt, telnet->buffer, telnet->length,
user_data);
#ifdef HAVE_ZLIB
/* if we are a client or a proxy and just received the
* COMPRESS2 begin marker, setup our zlib box and start
* handling the compressed stream if it's not already.
*/
if (telnet->buffer[0] == LIBTELNET_TELOPT_COMPRESS2 &&
if (telnet->sb_telopt == LIBTELNET_TELOPT_COMPRESS2 &&
telnet->z_inflate == 0 &&
(telnet->mode == LIBTELNET_MODE_CLIENT ||
telnet->mode == LIBTELNET_MODE_PROXY)) {
@ -337,7 +336,7 @@ static void _process(struct libtelnet_t *telnet, unsigned char *buffer,
start = i + 1;
telnet->state = LIBTELNET_STATE_DATA;
} else {
telnet->state = LIBTELNET_STATE_SB;
telnet->state = LIBTELNET_STATE_SB_DATA;
}
break;
/* something else -- protocol error */

5
libtelnet.h
View File

@ -101,7 +101,8 @@ enum libtelnet_state_t {
LIBTELNET_STATE_WILL,
LIBTELNET_STATE_WONT,
LIBTELNET_STATE_SB,
LIBTELNET_STATE_SB_IAC
LIBTELNET_STATE_SB_DATA,
LIBTELNET_STATE_SB_DATA_IAC
};
/* error codes */
@ -160,6 +161,8 @@ struct libtelnet_t {
enum libtelnet_state_t state;
/* processing mode */
enum libtelnet_mode_t mode;
/* current subnegotiation telopt */
unsigned char sb_telopt;
};
/* initialize a telnet state tracker */