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nuttx-apps/netutils/telnetc/telnetc.c
Xiang Xiao bf3e6e2367 Improvements for telnet server 
Author: Xiang Xiao <xiaoxiang@xiaomi.com>

    Check POLLHUP and POLLERR in telnet poll loop

      to handle the remote end close correctly

    Send "NVT"(network virtual terminal) as the default if getenv("TERM") return NULL

      telnet should trigger the error handling if inet_pton return zero
      since zero mean the string has format error

    Don't return 1 in _environ_telnet to avoid trigger the compression
    and remove the redundant TELNET_TELOPT_COMPRESS2 check

    Change telnet_error_u to telnet_error_e required by the coding standard

    Ensure telnet object get freed before the abnormal exit
2020-02-04 19:09:22 -03:00

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/****************************************************************************
* apps/netutils/telnetc/telnetc.c
*
* Leveraged from libtelnet, https://github.com/seanmiddleditch/libtelnet.
* Modified and re-released under the BSD license:
*
* Copyright (C) 2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* The original authors of libtelnet are listed below. Per their licesne,
* "The author or authors of this code dedicate any and all copyright
* interest in this code to the public domain. We make this dedication for
* the benefit of the public at large and to the detriment of our heirs and
* successors. We intend this dedication to be an overt act of
* relinquishment in perpetuity of all present and future rights to this
* code under copyright law."
*
* Author: Sean Middleditch <sean@sourcemud.org>
* (Also listed in the AUTHORS file are Jack Kelly <endgame.dos@gmail.com>
* and Katherine Flavel <kate@elide.org>)
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdarg.h>
#if defined(HAVE_ZLIB)
# include <zlib.h>
#endif
#include "netutils/telnetc.h"
/****************************************************************************
* Pre-proecessor Definitions
****************************************************************************/
/* Helper for Q-method option tracking */
#define Q_US(q) ( (q).state & 0x0F)
#define Q_HIM(q) (((q).state & 0xF0) >> 4)
#define Q_MAKE(us,him) ((us) | ((him) << 4))
/* Helper for the negotiation routines */
#define NEGOTIATE_EVENT(telnet,cmd,opt) \
ev.type = (cmd); \
ev.neg.telopt = (opt); \
(telnet)->eh((telnet), &ev, (telnet)->ud);
/* RFC1143 state names */
#define Q_NO 0
#define Q_YES 1
#define Q_WANTNO 2
#define Q_WANTYES 3
#define Q_WANTNO_OP 4
#define Q_WANTYES_OP 5
/* To send bags of unsigned chars */
#define _sendu(t, d, s) _send((t), (const char*)(d), (s))
/****************************************************************************
* Private Types
****************************************************************************/
/* Telnet state codes */
enum telnet_state_e
{
TELNET_STATE_DATA = 0,
TELNET_STATE_IAC,
TELNET_STATE_WILL,
TELNET_STATE_WONT,
TELNET_STATE_DO,
TELNET_STATE_DONT,
TELNET_STATE_SB,
TELNET_STATE_SB_DATA,
TELNET_STATE_SB_DATA_IAC
};
/* Telnet state tracker */
struct telnet_s
{
/* User data */
void *ud;
/* Telopt support table */
const struct telnet_telopt_s *telopts;
/* Event handler */
telnet_event_handler_t eh;
#if defined(HAVE_ZLIB)
/* zlib (mccp2) compression */
z_stream *z;
#endif
/* RFC1143 option negotiation states */
struct telnet_rfc1143_s *q;
/* Sub-request buffer */
char *buffer;
/* Current size of the buffer */
size_t buffer_size;
/* Current buffer write position (also length of buffer data) */
size_t buffer_pos;
/* Current state */
enum telnet_state_e state;
/* Option flags */
unsigned char flags;
/* Current subnegotiation telopt */
unsigned char sb_telopt;
/* Length of RFC1143 queue */
unsigned char q_size;
};
/* RFC1143 option negotiation state */
struct telnet_rfc1143_s
{
unsigned char telopt;
unsigned char state;
};
/****************************************************************************
* Private Data
****************************************************************************/
/* Buffer sizes */
static const size_t _buffer_sizes[] =
{
0, 512, 2048, 8192, 16384,
};
static const size_t _buffer_sizes_count = sizeof(_buffer_sizes) /
sizeof(_buffer_sizes[0]);
/****************************************************************************
* Private Functions
****************************************************************************/
/* Error generation function */
static enum telnet_error_e _error(struct telnet_s *telnet, unsigned line,
const char *func, enum telnet_error_e err,
int fatal, const char *fmt, ...)
{
union telnet_event_u ev;
char buffer[512];
va_list va;
/* Format informational text */
va_start(va, fmt);
vsnprintf(buffer, sizeof(buffer), fmt, va);
va_end(va);
/* Send error event to the user */
ev.type = fatal ? TELNET_EV_ERROR : TELNET_EV_WARNING;
ev.error.file = __FILE__;
ev.error.func = func;
ev.error.line = line;
ev.error.msg = buffer;
telnet->eh(telnet, &ev, telnet->ud);
return err;
}
/* Initialize the zlib box for a telnet box; if deflate is non-zero, it
* initializes zlib for delating (compression), otherwise for inflating
* (decompression). returns TELNET_EOK on success, something else on
* failure.
*/
#if defined(HAVE_ZLIB)
enum telnet_error_e _init_zlib(struct telnet_s *telnet, int deflate,
int err_fatal)
{
z_stream *z;
int rs;
/* If compression is already enabled, fail loudly */
if (telnet->z != 0)
{
return _error(telnet, __LINE__, __func__, TELNET_EBADVAL,
err_fatal, "cannot initialize compression twice");
}
/* Allocate zstream box */
if ((z = (z_stream *) calloc(1, sizeof(z_stream))) == 0)
{
return _error(telnet, __LINE__, __func__, TELNET_ENOMEM, err_fatal,
"malloc() failed: %d", errno);
}
/* Initialize */
if (deflate)
{
if ((rs = deflateInit(z, Z_DEFAULT_COMPRESSION)) != Z_OK)
{
free(z);
return _error(telnet, __LINE__, __func__, TELNET_ECOMPRESS,
err_fatal, "deflateInit() failed: %s", zError(rs));
}
telnet->flags |= TELNET_PFLAG_DEFLATE;
}
else
{
if ((rs = inflateInit(z)) != Z_OK)
{
free(z);
return _error(telnet, __LINE__, __func__, TELNET_ECOMPRESS,
err_fatal, "inflateInit() failed: %s", zError(rs));
}
telnet->flags &= ~TELNET_PFLAG_DEFLATE;
}
telnet->z = z;
return TELNET_EOK;
}
#endif /* HAVE_ZLIB */
/* Push bytes out, compressing them first if need be */
static void _send(struct telnet_s *telnet, const char *buffer, size_t size)
{
union telnet_event_u ev;
#if defined(HAVE_ZLIB)
/* If we have a deflate (compression) zlib box, use it */
if (telnet->z != 0 && telnet->flags & TELNET_PFLAG_DEFLATE)
{
char deflate_buffer[1024];
int rs;
/* Initialize z state */
telnet->z->next_in = (unsigned char *)buffer;
telnet->z->avail_in = (unsigned int)size;
telnet->z->next_out = (unsigned char *)deflate_buffer;
telnet->z->avail_out = sizeof(deflate_buffer);
/* Deflate until buffer exhausted and all output is produced */
while (telnet->z->avail_in > 0 || telnet->z->avail_out == 0)
{
/* Compress */
if ((rs = deflate(telnet->z, Z_SYNC_FLUSH)) != Z_OK)
{
_error(telnet, __LINE__, __func__, TELNET_ECOMPRESS, 1,
"deflate() failed: %s", zError(rs));
deflateEnd(telnet->z);
free(telnet->z);
telnet->z = 0;
break;
}
/* Send event */
ev.type = TELNET_EV_SEND;
ev.data.buffer = deflate_buffer;
ev.data.size = sizeof(deflate_buffer) - telnet->z->avail_out;
telnet->eh(telnet, &ev, telnet->ud);
/* Prepare output buffer for next run */
telnet->z->next_out = (unsigned char *)deflate_buffer;
telnet->z->avail_out = sizeof(deflate_buffer);
}
/* Do not continue with remaining code */
return;
}
#endif /* HAVE_ZLIB */
ev.type = TELNET_EV_SEND;
ev.data.buffer = buffer;
ev.data.size = size;
telnet->eh(telnet, &ev, telnet->ud);
}
/* Check if we support a particular telopt; if us is non-zero, we
* check if we (local) supports it, otherwise we check if he (remote)
* supports it. return non-zero if supported, zero if not supported.
*/
static inline int _check_telopt(struct telnet_s *telnet,
unsigned char telopt, int us)
{
int i;
/* If we have no telopts table, we obviously don't support it */
if (telnet->telopts == 0)
{
return 0;
}
/* Loop until found or end marker (us and him both 0) */
for (i = 0; telnet->telopts[i].telopt != -1; ++i)
{
if (telnet->telopts[i].telopt == telopt)
{
if (us && telnet->telopts[i].us == TELNET_WILL)
{
return 1;
}
else if (!us && telnet->telopts[i].him == TELNET_DO)
{
return 1;
}
else
{
return 0;
}
}
}
/* Not found, so not supported */
return 0;
}
/* Retrieve RFC1143 option state */
static inline struct telnet_rfc1143_s _get_rfc1143(struct telnet_s *telnet,
unsigned char telopt)
{
struct telnet_rfc1143_s empty;
int i;
/* Search for entry */
for (i = 0; i != telnet->q_size; ++i)
{
if (telnet->q[i].telopt == telopt)
{
return telnet->q[i];
}
}
/* Not found, return empty value */
empty.telopt = telopt;
empty.state = 0;
return empty;
}
/* Save RFC1143 option state */
static inline void _set_rfc1143(struct telnet_s *telnet, unsigned char telopt,
char us, char him)
{
struct telnet_rfc1143_s *qtmp;
int i;
/* Search for entry */
for (i = 0; i != telnet->q_size; ++i)
{
if (telnet->q[i].telopt == telopt)
{
telnet->q[i].state = Q_MAKE(us, him);
return;
}
}
/* we're going to need to track state for it, so grow the queue by 4 (four)
* elements and put the telopt into it; bail on allocation error. we go by
* four because it seems like a reasonable guess as to the number of enabled
* options for most simple code, and it allows for an acceptable number of
* reallocations for complex code.
*/
qtmp = (struct telnet_rfc1143_s *)
realloc(telnet->q,
sizeof(struct telnet_rfc1143_s) * (telnet->q_size + 4));
if (qtmp == 0)
{
_error(telnet, __LINE__, __func__, TELNET_ENOMEM, 0,
"realloc() failed: %d", errno);
return;
}
memset(&qtmp[telnet->q_size], 0, sizeof(struct telnet_rfc1143_s) * 4);
telnet->q = qtmp;
telnet->q[telnet->q_size].telopt = telopt;
telnet->q[telnet->q_size].state = Q_MAKE(us, him);
telnet->q_size += 4;
}
/* Send negotiation bytes */
static inline void _send_negotiate(struct telnet_s *telnet, unsigned char cmd,
unsigned char telopt)
{
unsigned char bytes[3];
bytes[0] = TELNET_IAC;
bytes[1] = cmd;
bytes[2] = telopt;
_sendu(telnet, bytes, 3);
}
/* Negotiation handling magic for RFC1143 */
static void _negotiate(struct telnet_s *telnet, unsigned char telopt)
{
union telnet_event_u ev;
struct telnet_rfc1143_s q;
/* In PROXY mode, just pass it thru and do nothing */
if (telnet->flags & TELNET_FLAG_PROXY)
{
switch ((int)telnet->state)
{
case TELNET_STATE_WILL:
NEGOTIATE_EVENT(telnet, TELNET_EV_WILL, telopt);
break;
case TELNET_STATE_WONT:
NEGOTIATE_EVENT(telnet, TELNET_EV_WONT, telopt);
break;
case TELNET_STATE_DO:
NEGOTIATE_EVENT(telnet, TELNET_EV_DO, telopt);
break;
case TELNET_STATE_DONT:
NEGOTIATE_EVENT(telnet, TELNET_EV_DONT, telopt);
break;
}
return;
}
/* Lookup the current state of the option */
q = _get_rfc1143(telnet, telopt);
/* Start processing... */
switch ((int)telnet->state)
{
/* Request to enable option on remote end or confirm DO */
case TELNET_STATE_WILL:
switch (Q_HIM(q))
{
case Q_NO:
if (_check_telopt(telnet, telopt, 0))
{
_set_rfc1143(telnet, telopt, Q_US(q), Q_YES);
_send_negotiate(telnet, TELNET_DO, telopt);
NEGOTIATE_EVENT(telnet, TELNET_EV_WILL, telopt);
}
else
_send_negotiate(telnet, TELNET_DONT, telopt);
break;
case Q_WANTNO:
_set_rfc1143(telnet, telopt, Q_US(q), Q_NO);
NEGOTIATE_EVENT(telnet, TELNET_EV_WONT, telopt);
_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
"DONT answered by WILL");
break;
case Q_WANTNO_OP:
_set_rfc1143(telnet, telopt, Q_US(q), Q_YES);
NEGOTIATE_EVENT(telnet, TELNET_EV_WILL, telopt);
_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
"DONT answered by WILL");
break;
case Q_WANTYES:
_set_rfc1143(telnet, telopt, Q_US(q), Q_YES);
NEGOTIATE_EVENT(telnet, TELNET_EV_WILL, telopt);
break;
case Q_WANTYES_OP:
_set_rfc1143(telnet, telopt, Q_US(q), Q_WANTNO);
_send_negotiate(telnet, TELNET_DONT, telopt);
NEGOTIATE_EVENT(telnet, TELNET_EV_WILL, telopt);
break;
}
break;
/* Request to disable option on remote end, confirm DONT, reject DO */
case TELNET_STATE_WONT:
switch (Q_HIM(q))
{
case Q_YES:
_set_rfc1143(telnet, telopt, Q_US(q), Q_NO);
_send_negotiate(telnet, TELNET_DONT, telopt);
NEGOTIATE_EVENT(telnet, TELNET_EV_WONT, telopt);
break;
case Q_WANTNO:
_set_rfc1143(telnet, telopt, Q_US(q), Q_NO);
NEGOTIATE_EVENT(telnet, TELNET_EV_WONT, telopt);
break;
case Q_WANTNO_OP:
_set_rfc1143(telnet, telopt, Q_US(q), Q_WANTYES);
NEGOTIATE_EVENT(telnet, TELNET_EV_DO, telopt);
break;
case Q_WANTYES:
case Q_WANTYES_OP:
_set_rfc1143(telnet, telopt, Q_US(q), Q_NO);
break;
}
break;
/* Request to enable option on local end or confirm WILL */
case TELNET_STATE_DO:
switch (Q_US(q))
{
case Q_NO:
if (_check_telopt(telnet, telopt, 1))
{
_set_rfc1143(telnet, telopt, Q_YES, Q_HIM(q));
_send_negotiate(telnet, TELNET_WILL, telopt);
NEGOTIATE_EVENT(telnet, TELNET_EV_DO, telopt);
}
else
_send_negotiate(telnet, TELNET_WONT, telopt);
break;
case Q_WANTNO:
_set_rfc1143(telnet, telopt, Q_NO, Q_HIM(q));
NEGOTIATE_EVENT(telnet, TELNET_EV_DONT, telopt);
_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
"WONT answered by DO");
break;
case Q_WANTNO_OP:
_set_rfc1143(telnet, telopt, Q_YES, Q_HIM(q));
NEGOTIATE_EVENT(telnet, TELNET_EV_DO, telopt);
_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
"WONT answered by DO");
break;
case Q_WANTYES:
_set_rfc1143(telnet, telopt, Q_YES, Q_HIM(q));
NEGOTIATE_EVENT(telnet, TELNET_EV_DO, telopt);
break;
case Q_WANTYES_OP:
_set_rfc1143(telnet, telopt, Q_WANTNO, Q_HIM(q));
_send_negotiate(telnet, TELNET_WONT, telopt);
NEGOTIATE_EVENT(telnet, TELNET_EV_DO, telopt);
break;
}
break;
/* Request to disable option on local end, confirm WONT, reject WILL */
case TELNET_STATE_DONT:
switch (Q_US(q))
{
case Q_YES:
_set_rfc1143(telnet, telopt, Q_NO, Q_HIM(q));
_send_negotiate(telnet, TELNET_WONT, telopt);
NEGOTIATE_EVENT(telnet, TELNET_EV_DONT, telopt);
break;
case Q_WANTNO:
_set_rfc1143(telnet, telopt, Q_NO, Q_HIM(q));
NEGOTIATE_EVENT(telnet, TELNET_EV_WONT, telopt);
break;
case Q_WANTNO_OP:
_set_rfc1143(telnet, telopt, Q_WANTYES, Q_HIM(q));
_send_negotiate(telnet, TELNET_WILL, telopt);
NEGOTIATE_EVENT(telnet, TELNET_EV_WILL, telopt);
break;
case Q_WANTYES:
case Q_WANTYES_OP:
_set_rfc1143(telnet, telopt, Q_NO, Q_HIM(q));
break;
}
break;
}
}
/* Process an ENVIRON/NEW-ENVIRON subnegotiation buffer
*
* the algorithm and approach used here is kind of a hack,
* but it reduces the number of memory allocations we have
* to make.
*
* we copy the bytes back into the buffer, starting at the very
* beginning, which makes it easy to handle the ENVIRON ESC
* escape mechanism as well as ensure the variable name and
* value strings are NUL-terminated, all while fitting inside
* of the original buffer.
*/
static int _environ_telnet(struct telnet_s *telnet, unsigned char type,
char *buffer, size_t size)
{
union telnet_event_u ev;
struct telnet_environ_s *values = 0;
char *c;
char *last;
char *out;
size_t index;
size_t count;
/* If we have no data, just pass it through */
if (size == 0)
{
return 0;
}
/* First byte must be a valid command */
if ((unsigned)buffer[0] != TELNET_ENVIRON_SEND &&
(unsigned)buffer[0] != TELNET_ENVIRON_IS &&
(unsigned)buffer[0] != TELNET_ENVIRON_INFO)
{
_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
"telopt %d subneg has invalid command", type);
return 0;
}
/* Store ENVIRON command */
ev.envevent.cmd = buffer[0];
/* If we have no arguments, send an event with no data end return */
if (size == 1)
{
/* No list of variables given */
ev.envevent.values = 0;
ev.envevent.size = 0;
/* Invoke event with our arguments */
ev.type = TELNET_EV_ENVIRON;
telnet->eh(telnet, &ev, telnet->ud);
return 0;
}
/* Every second byte must be VAR or USERVAR, if present */
if ((unsigned)buffer[1] != TELNET_ENVIRON_VAR &&
(unsigned)buffer[1] != TELNET_ENVIRON_USERVAR)
{
_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
"telopt %d subneg missing variable type", type);
return 0;
}
/* Ensure last byte is not an escape byte (makes parsing later easier) */
if ((unsigned)buffer[size - 1] == TELNET_ENVIRON_ESC)
{
_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
"telopt %d subneg ends with ESC", type);
return 0;
}
/* Count arguments; each valid entry starts with VAR or USERVAR */
count = 0;
for (c = buffer + 1; c < buffer + size; ++c)
{
if (*c == TELNET_ENVIRON_VAR || *c == TELNET_ENVIRON_USERVAR)
{
++count;
}
else if (*c == TELNET_ENVIRON_ESC)
{
/* Skip the next byte */
++c;
}
}
/* Allocate argument array, bail on error */
values = (struct telnet_environ_s *)
calloc(count, sizeof(struct telnet_environ_s));
if (values == 0)
{
_error(telnet, __LINE__, __func__, TELNET_ENOMEM, 0,
"calloc() failed: %d", errno);
return 0;
}
/* Parse argument array strings */
out = buffer;
c = buffer + 1;
for (index = 0; index != count; ++index)
{
/* Remember the variable type (will be VAR or USERVAR) */
values[index].type = *c++;
/* Scan until we find an end-marker, and buffer up unescaped bytes into
* our buffer.
*/
last = out;
while (c < buffer + size)
{
/* Stop at the next variable or at the value */
if ((unsigned)*c == TELNET_ENVIRON_VAR ||
(unsigned)*c == TELNET_ENVIRON_VALUE ||
(unsigned)*c == TELNET_ENVIRON_USERVAR)
{
break;
}
/* Buffer next byte (taking into account ESC) */
if (*c == TELNET_ENVIRON_ESC)
{
++c;
}
*out++ = *c++;
}
*out++ = '\0';
/* Store the variable name we have just received */
values[index].var = last;
values[index].value = "";
/* If we got a value, find the next end marker and store the value;
* otherwise, store empty string.
*/
if (c < buffer + size && *c == TELNET_ENVIRON_VALUE)
{
++c;
last = out;
while (c < buffer + size)
{
/* Stop when we find the start of the next variable */
if ((unsigned)*c == TELNET_ENVIRON_VAR ||
(unsigned)*c == TELNET_ENVIRON_USERVAR)
{
break;
}
/* Buffer next byte (taking into account ESC) */
if (*c == TELNET_ENVIRON_ESC)
{
++c;
}
*out++ = *c++;
}
*out++ = '\0';
/* Store the variable value */
values[index].value = last;
}
}
/* Pass values array and count to event */
ev.envevent.values = values;
ev.envevent.size = count;
/* Invoke event with our arguments */
ev.type = TELNET_EV_ENVIRON;
telnet->eh(telnet, &ev, telnet->ud);
/* Clean up */
free(values);
return 0;
}
/* Process an MSSP subnegotiation buffer */
static int _mssp_telnet(struct telnet_s *telnet, char *buffer, size_t size)
{
union telnet_event_u ev;
struct telnet_environ_s *values;
char *var = 0;
char *c, *last, *out;
size_t i, count;
unsigned char next_type;
/* If we have no data, just pass it through */
if (size == 0)
{
return 0;
}
/* First byte must be a VAR */
if ((unsigned)buffer[0] != TELNET_MSSP_VAR)
{
_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
"MSSP subnegotiation has invalid data");
return 0;
}
/* Count the arguments, any part that starts with VALUE */
for (count = 0, i = 0; i != size; ++i)
{
if ((unsigned)buffer[i] == TELNET_MSSP_VAL)
{
++count;
}
}
/* Allocate argument array, bail on error */
values = (struct telnet_environ_s *)
calloc(count, sizeof(struct telnet_environ_s));
if (values == 0)
{
_error(telnet, __LINE__, __func__, TELNET_ENOMEM, 0,
"calloc() failed: %d", errno);
return 0;
}
ev.mssp.values = values;
ev.mssp.size = count;
/* Allocate strings in argument array */
out = last = buffer;
next_type = buffer[0];
for (i = 0, c = buffer + 1; c < buffer + size;)
{
/* Search for end marker */
while (c < buffer + size && (unsigned)*c != TELNET_MSSP_VAR &&
(unsigned)*c != TELNET_MSSP_VAL)
{
*out++ = *c++;
}
*out++ = '\0';
/* If it's a variable name, just store the name for now */
if (next_type == TELNET_MSSP_VAR)
{
var = last;
}
else if (next_type == TELNET_MSSP_VAL && var != 0)
{
values[i].var = var;
values[i].value = last;
++i;
}
else
{
_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
"invalid MSSP subnegotiation data");
free(values);
return 0;
}
/* Remember our next type and increment c for next loop run */
last = out;
next_type = *c++;
}
/* Invoke event with our arguments */
ev.type = TELNET_EV_MSSP;
telnet->eh(telnet, &ev, telnet->ud);
/* Clean up */
free(values);
return 0;
}
/* Parse ZMP command subnegotiation buffers */
static int _zmp_telnet(struct telnet_s *telnet, const char *buffer, size_t size)
{
union telnet_event_u ev;
char **argv;
const char *c;
size_t i;
size_t argc;
/* Make sure this is a valid ZMP buffer */
if (size == 0 || buffer[size - 1] != 0)
{
_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
"incomplete ZMP frame");
return 0;
}
/* Count arguments */
for (argc = 0, c = buffer; c != buffer + size; ++argc)
{
c += strlen(c) + 1;
}
/* Allocate argument array, bail on error */
if ((argv = (char **)calloc(argc, sizeof(char *))) == 0)
{
_error(telnet, __LINE__, __func__, TELNET_ENOMEM, 0,
"calloc() failed: %d", errno);
return 0;
}
/* Populate argument array */
for (i = 0, c = buffer; i != argc; ++i)
{
argv[i] = (char *)c;
c += strlen(c) + 1;
}
/* Invoke event with our arguments */
ev.type = TELNET_EV_ZMP;
ev.zmp.argv = (const char **)argv;
ev.zmp.argc = argc;
telnet->eh(telnet, &ev, telnet->ud);
/* Clean up */
free(argv);
return 0;
}
/* Parse TERMINAL-TYPE command subnegotiation buffers */
static int _ttype_telnet(struct telnet_s *telnet, const char *buffer,
size_t size)
{
union telnet_event_u ev;
/* Make sure request is not empty */
if (size == 0)
{
_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
"incomplete TERMINAL-TYPE request");
return 0;
}
/* Make sure request has valid command type */
if (buffer[0] != TELNET_TTYPE_IS && buffer[0] != TELNET_TTYPE_SEND)
{
_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
"TERMINAL-TYPE request has invalid type");
return 0;
}
/* Send proper event */
if (buffer[0] == TELNET_TTYPE_IS)
{
char *name;
/* Allocate space for name */
if ((name = (char *)malloc(size)) == 0)
{
_error(telnet, __LINE__, __func__, TELNET_ENOMEM, 0,
"malloc() failed: %d", errno);
return 0;
}
memcpy(name, buffer + 1, size - 1);
name[size - 1] = '\0';
ev.type = TELNET_EV_TTYPE;
ev.ttype.cmd = TELNET_TTYPE_IS;
ev.ttype.name = name;
telnet->eh(telnet, &ev, telnet->ud);
/* Clean up */
free(name);
}
else
{
ev.type = TELNET_EV_TTYPE;
ev.ttype.cmd = TELNET_TTYPE_SEND;
ev.ttype.name = 0;
telnet->eh(telnet, &ev, telnet->ud);
}
return 0;
}
/* Process a subnegotiation buffer; return non-zero if the current buffer
* must be aborted and reprocessed due to COMPRESS2 being activated
*/
static int _subnegotiate(struct telnet_s *telnet)
{
union telnet_event_u ev;
/* Standard subnegotiation event */
ev.type = TELNET_EV_SUBNEGOTIATION;
ev.sub.telopt = telnet->sb_telopt;
ev.sub.buffer = telnet->buffer;
ev.sub.size = telnet->buffer_pos;
telnet->eh(telnet, &ev, telnet->ud);
switch (telnet->sb_telopt)
{
#if defined(HAVE_ZLIB)
/* Received COMPRESS2 begin marker, setup our zlib box and start handling
* the compressed stream if it's not already.
*/
case TELNET_TELOPT_COMPRESS2:
if (_init_zlib(telnet, 0, 1) != TELNET_EOK)
{
return 0;
}
/* Notify app that compression was enabled */
ev.type = TELNET_EV_COMPRESS;
ev.compress.state = 1;
telnet->eh(telnet, &ev, telnet->ud);
return 1;
#endif /* HAVE_ZLIB */
/* Specially handled subnegotiation telopt types */
case TELNET_TELOPT_ZMP:
return _zmp_telnet(telnet, telnet->buffer, telnet->buffer_pos);
case TELNET_TELOPT_TTYPE:
return _ttype_telnet(telnet, telnet->buffer, telnet->buffer_pos);
case TELNET_TELOPT_ENVIRON:
case TELNET_TELOPT_NEW_ENVIRON:
return _environ_telnet(telnet, telnet->sb_telopt, telnet->buffer,
telnet->buffer_pos);
case TELNET_TELOPT_MSSP:
return _mssp_telnet(telnet, telnet->buffer, telnet->buffer_pos);
default:
return 0;
}
}
/****************************************************************************
* Name: telnet_init
*
* Description:
* Initialize a telnet state tracker.
*
* This function initializes a new state tracker, which is used for all
* other libtelnet functions. Each connection must have its own
* telnet state tracker object.
*
* Input Parameters:
* telopts Table of TELNET options the application supports.
* eh Event handler function called for every event.
* flags 0 or TELNET_FLAG_PROXY.
* user_data Optional data pointer that will be passsed to eh.
*
* Returned Value:
* Telent state tracker object.
*
****************************************************************************/
struct telnet_s *telnet_init(const struct telnet_telopt_s *telopts,
telnet_event_handler_t eh,
unsigned char flags,
void *user_data)
{
/* Allocate structure */
struct telnet_s *telnet = (struct telnet_s *) calloc(1, sizeof(struct telnet_s));
if (telnet == 0)
{
return 0;
}
/* Initialize data */
telnet->ud = user_data;
telnet->telopts = telopts;
telnet->eh = eh;
telnet->flags = flags;
return telnet;
}
/****************************************************************************
* Name: telnet_free
*
* Description:
* Free up any memory allocated by a state tracker.
*
* This function must be called when a telnet state tracker is no
* longer needed (such as after the connection has been closed) to
* release any memory resources used by the state tracker.
*
* Input Parameters:
* telnet Telnet state tracker object.
*
****************************************************************************/
void telnet_free(struct telnet_s *telnet)
{
/* Free sub-request buffer */
if (telnet->buffer != 0)
{
free(telnet->buffer);
telnet->buffer = 0;
telnet->buffer_size = 0;
telnet->buffer_pos = 0;
}
#if defined(HAVE_ZLIB)
/* Free zlib box */
if (telnet->z != 0)
{
if (telnet->flags & TELNET_PFLAG_DEFLATE)
{
deflateEnd(telnet->z);
}
else
{
inflateEnd(telnet->z);
}
free(telnet->z);
telnet->z = 0;
}
#endif /* HAVE_ZLIB */
/* Free RFC1143 queue */
if (telnet->q)
{
free(telnet->q);
telnet->q = 0;
telnet->q_size = 0;
}
/* Free the telnet structure itself */
free(telnet);
}
/* Push a byte into the telnet buffer */
static enum telnet_error_e _buffer_byte(struct telnet_s *telnet,
unsigned char byte)
{
char *new_buffer;
size_t i;
/* Check if we're out of room */
if (telnet->buffer_pos == telnet->buffer_size)
{
/* Find the next buffer size */
for (i = 0; i != _buffer_sizes_count; ++i)
{
if (_buffer_sizes[i] == telnet->buffer_size)
{
break;
}
}
/* Overflow -- can't grow any more */
if (i >= _buffer_sizes_count - 1)
{
_error(telnet, __LINE__, __func__, TELNET_EOVERFLOW, 0,
"subnegotiation buffer size limit reached");
return TELNET_EOVERFLOW;
}
/* (Re)allocate buffer */
new_buffer = (char *)realloc(telnet->buffer, _buffer_sizes[i + 1]);
if (new_buffer == 0)
{
_error(telnet, __LINE__, __func__, TELNET_ENOMEM, 0,
"realloc() failed");
return TELNET_ENOMEM;
}
telnet->buffer = new_buffer;
telnet->buffer_size = _buffer_sizes[i + 1];
}
/* Push the byte, all set */
telnet->buffer[telnet->buffer_pos++] = byte;
return TELNET_EOK;
}
static void _process(struct telnet_s *telnet, const char *buffer,
size_t size)
{
union telnet_event_u ev;
unsigned char byte;
size_t start;
size_t i;
for (i = start = 0; i != size; ++i)
{
byte = buffer[i];
switch (telnet->state)
{
/* Regular data */
case TELNET_STATE_DATA:
/* On an IAC byte, pass through all pending bytes and switch states */
if (byte == TELNET_IAC)
{
if (i != start)
{
ev.type = TELNET_EV_DATA;
ev.data.buffer = buffer + start;
ev.data.size = i - start;
telnet->eh(telnet, &ev, telnet->ud);
}
telnet->state = TELNET_STATE_IAC;
}
break;
/* IAC command */
case TELNET_STATE_IAC:
switch (byte)
{
/* Subnegotiation */
case TELNET_SB:
telnet->state = TELNET_STATE_SB;
break;
/* Negotiation commands */
case TELNET_WILL:
telnet->state = TELNET_STATE_WILL;
break;
case TELNET_WONT:
telnet->state = TELNET_STATE_WONT;
break;
case TELNET_DO:
telnet->state = TELNET_STATE_DO;
break;
case TELNET_DONT:
telnet->state = TELNET_STATE_DONT;
break;
/* IAC escaping */
case TELNET_IAC:
/* Event */
ev.type = TELNET_EV_DATA;
ev.data.buffer = (char *)&byte;
ev.data.size = 1;
telnet->eh(telnet, &ev, telnet->ud);
/* State update */
start = i + 1;
telnet->state = TELNET_STATE_DATA;
break;
/* Some other command */
default:
/* Event */
ev.type = TELNET_EV_IAC;
ev.iac.cmd = byte;
telnet->eh(telnet, &ev, telnet->ud);
/* State update */
start = i + 1;
telnet->state = TELNET_STATE_DATA;
}
break;
/* Negotiation commands */
case TELNET_STATE_WILL:
case TELNET_STATE_WONT:
case TELNET_STATE_DO:
case TELNET_STATE_DONT:
_negotiate(telnet, byte);
start = i + 1;
telnet->state = TELNET_STATE_DATA;
break;
/* Subnegotiation -- determine subnegotiation telopt */
case TELNET_STATE_SB:
telnet->sb_telopt = byte;
telnet->buffer_pos = 0;
telnet->state = TELNET_STATE_SB_DATA;
break;
/* Subnegotiation -- buffer bytes until end request */
case TELNET_STATE_SB_DATA:
/* IAC command in subnegotiation -- either IAC SE or IAC IAC */
if (byte == TELNET_IAC)
{
telnet->state = TELNET_STATE_SB_DATA_IAC;
}
else if (telnet->sb_telopt == TELNET_TELOPT_COMPRESS &&
byte == TELNET_WILL)
{
/* In 1998 MCCP used TELOPT 85 and the protocol defined an
* invalid subnegotiation sequence (IAC SB 85 WILL SE) to start
* compression. Subsequently MCCP version 2 was created in 2000
* using TELOPT 86 and a valid subnegotiation (IAC SB 86 IAC SE).
* libtelnet for now just captures and discards MCCPv1 sequences.
*/
start = i + 2;
telnet->state = TELNET_STATE_DATA;
/* Buffer the byte, or bail if we can't */
}
else if (_buffer_byte(telnet, byte) != TELNET_EOK)
{
start = i + 1;
telnet->state = TELNET_STATE_DATA;
}
break;
/* IAC escaping inside a subnegotiation */
case TELNET_STATE_SB_DATA_IAC:
switch (byte)
{
/* End subnegotiation */
case TELNET_SE:
/* Return to default state */
start = i + 1;
telnet->state = TELNET_STATE_DATA;
/* Process subnegotiation */
if (_subnegotiate(telnet) != 0)
{
/* Any remaining bytes in the buffer are compressed. we have
* to re-invoke telnet_recv to get those bytes inflated and
* abort trying to process the remaining compressed bytes in
* the current _process buffer argument.
*/
telnet_recv(telnet, &buffer[start], size - start);
return;
}
break;
/* Escaped IAC byte */
case TELNET_IAC:
/* Push IAC into buffer */
if (_buffer_byte(telnet, TELNET_IAC) != TELNET_EOK)
{
start = i + 1;
telnet->state = TELNET_STATE_DATA;
}
else
{
telnet->state = TELNET_STATE_SB_DATA;
}
break;
/* Something else -- protocol error. attempt to process content
* in subnegotiation buffer, then evaluate the given command as
* an IAC code.
*/
default:
_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
"unexpected byte after IAC inside SB: %d", byte);
/* Enter IAC state */
start = i + 1;
telnet->state = TELNET_STATE_IAC;
/* Process subnegotiation; see comment in
* TELNET_STATE_SB_DATA_IAC about invoking telnet_recv()
*/
if (_subnegotiate(telnet) != 0)
{
telnet_recv(telnet, &buffer[start], size - start);
return;
}
else
{
/* Recursive call to get the current input byte processed as
* a regular IAC command. we could use a goto, but that
* would be gross.
*/
_process(telnet, (char *)&byte, 1);
}
break;
}
break;
}
}
/* Pass through any remaining bytes */
if (telnet->state == TELNET_STATE_DATA && i != start)
{
ev.type = TELNET_EV_DATA;
ev.data.buffer = buffer + start;
ev.data.size = i - start;
telnet->eh(telnet, &ev, telnet->ud);
}
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: telnet_recv
*
* Description:
* Push a byte buffer into the state tracker.
*
* Passes one or more bytes to the telnet state tracker for
* protocol parsing. The byte buffer is most often going to be
* the buffer that recv() was called for while handling the
* connection.
*
* Input Parameters:
* telnet Telnet state tracker object.
* buffer Pointer to byte buffer.
* size Number of bytes pointed to by buffer.
*
****************************************************************************/
void telnet_recv(struct telnet_s *telnet, const char *buffer, size_t size)
{
#if defined(HAVE_ZLIB)
/* If we have an inflate (decompression) zlib stream, use it */
if (telnet->z != 0 && !(telnet->flags & TELNET_PFLAG_DEFLATE))
{
char inflate_buffer[1024];
int rs;
/* Initialize zlib state */
telnet->z->next_in = (unsigned char *)buffer;
telnet->z->avail_in = (unsigned int)size;
telnet->z->next_out = (unsigned char *)inflate_buffer;
telnet->z->avail_out = sizeof(inflate_buffer);
/* Inflate until buffer exhausted and all output is produced */
while (telnet->z->avail_in > 0 || telnet->z->avail_out == 0)
{
/* Reset output buffer */
/* Decompress */
rs = inflate(telnet->z, Z_SYNC_FLUSH);
/* Process the decompressed bytes on success */
if (rs == Z_OK || rs == Z_STREAM_END)
{
_process(telnet, inflate_buffer, sizeof(inflate_buffer) -
telnet->z->avail_out);
}
else
{
_error(telnet, __LINE__, __func__, TELNET_ECOMPRESS, 1,
"inflate() failed: %s", zError(rs));
}
/* Prepare output buffer for next run */
telnet->z->next_out = (unsigned char *)inflate_buffer;
telnet->z->avail_out = sizeof(inflate_buffer);
/* On error (or on end of stream) disable further inflation */
if (rs != Z_OK)
{
union telnet_event_u ev;
/* Disable compression */
inflateEnd(telnet->z);
free(telnet->z);
telnet->z = 0;
/* Send event */
ev.type = TELNET_EV_COMPRESS;
ev.compress.state = 0;
telnet->eh(telnet, &ev, telnet->ud);
break;
}
}
/* COMPRESS2 is not negotiated, just process */
}
else
#endif /* HAVE_ZLIB */
_process(telnet, buffer, size);
}
/****************************************************************************
* Name: telnet_iac
*
* Description:
* Send a telnet command.
*
* Input Parameters:
* telnet Telnet state tracker object.
* cmd Command to send.
*
****************************************************************************/
void telnet_iac(struct telnet_s *telnet, unsigned char cmd)
{
unsigned char bytes[2];
bytes[0] = TELNET_IAC;
bytes[1] = cmd;
_sendu(telnet, bytes, 2);
}
/****************************************************************************
* Name: telnet_negotiate
*
* Description:
* Send negotiation command.
*
* Internally, libtelnet uses RFC1143 option negotiation rules.
* The negotiation commands sent with this function may be ignored
* if they are determined to be redundant.
*
* Input Parameters:
* telnet Telnet state tracker object.
* cmd TELNET_WILL, TELNET_WONT, TELNET_DO, or TELNET_DONT.
* opt One of the TELNET_TELOPT_* values.
*
****************************************************************************/
void telnet_negotiate(struct telnet_s *telnet, unsigned char cmd,
unsigned char telopt)
{
struct telnet_rfc1143_s q;
/* If we're in proxy mode, just send it now */
if (telnet->flags & TELNET_FLAG_PROXY)
{
unsigned char bytes[3];
bytes[0] = TELNET_IAC;
bytes[1] = cmd;
bytes[2] = telopt;
_sendu(telnet, bytes, 3);
return;
}
/* Get current option states */
q = _get_rfc1143(telnet, telopt);
switch (cmd)
{
/* Advertise willingess to support an option */
case TELNET_WILL:
switch (Q_US(q))
{
case Q_NO:
_set_rfc1143(telnet, telopt, Q_WANTYES, Q_HIM(q));
_send_negotiate(telnet, TELNET_WILL, telopt);
break;
case Q_WANTNO:
_set_rfc1143(telnet, telopt, Q_WANTNO_OP, Q_HIM(q));
break;
case Q_WANTYES_OP:
_set_rfc1143(telnet, telopt, Q_WANTYES, Q_HIM(q));
break;
}
break;
/* Force turn-off of locally enabled option */
case TELNET_WONT:
switch (Q_US(q))
{
case Q_YES:
_set_rfc1143(telnet, telopt, Q_WANTNO, Q_HIM(q));
_send_negotiate(telnet, TELNET_WONT, telopt);
break;
case Q_WANTYES:
_set_rfc1143(telnet, telopt, Q_WANTYES_OP, Q_HIM(q));
break;
case Q_WANTNO_OP:
_set_rfc1143(telnet, telopt, Q_WANTNO, Q_HIM(q));
break;
}
break;
/* Ask remote end to enable an option */
case TELNET_DO:
switch (Q_HIM(q))
{
case Q_NO:
_set_rfc1143(telnet, telopt, Q_US(q), Q_WANTYES);
_send_negotiate(telnet, TELNET_DO, telopt);
break;
case Q_WANTNO:
_set_rfc1143(telnet, telopt, Q_US(q), Q_WANTNO_OP);
break;
case Q_WANTYES_OP:
_set_rfc1143(telnet, telopt, Q_US(q), Q_WANTYES);
break;
}
break;
/* Demand remote end disable an option */
case TELNET_DONT:
switch (Q_HIM(q))
{
case Q_YES:
_set_rfc1143(telnet, telopt, Q_US(q), Q_WANTNO);
_send_negotiate(telnet, TELNET_DONT, telopt);
break;
case Q_WANTYES:
_set_rfc1143(telnet, telopt, Q_US(q), Q_WANTYES_OP);
break;
case Q_WANTNO_OP:
_set_rfc1143(telnet, telopt, Q_US(q), Q_WANTNO);
break;
}
break;
}
}
/****************************************************************************
* Name: telnet_send
*
* Description:
* Send non-command data (escapes IAC bytes).
*
* Input Parameters:
* telnet Telnet state tracker object.
* buffer Buffer of bytes to send.
* size Number of bytes to send.
*
****************************************************************************/
void telnet_send(struct telnet_s *telnet, const char *buffer, size_t size)
{
size_t l;
size_t i;
for (l = i = 0; i != size; ++i)
{
/* Dump prior portion of text, send escaped bytes */
if (buffer[i] == (char)TELNET_IAC)
{
/* Dump prior text if any */
if (i != l)
{
_send(telnet, buffer + l, i - l);
}
l = i + 1;
/* Send escape */
telnet_iac(telnet, TELNET_IAC);
}
}
/* Send whatever portion of buffer is left */
if (i != l)
{
_send(telnet, buffer + l, i - l);
}
}
/****************************************************************************
* Name: telnet_begin_sb
*
* Description:
* Begin a sub-negotiation command.
*
* Sends IAC SB followed by the telopt code. All following data sent
* will be part of the sub-negotiation, until telnet_finish_sb() is
* called.
*
* Input Parameters:
* telnet Telnet state tracker object.
* telopt One of the TELNET_TELOPT_* values.
*
****************************************************************************/
void telnet_begin_sb(struct telnet_s *telnet, unsigned char telopt)
{
unsigned char sb[3];
sb[0] = TELNET_IAC;
sb[1] = TELNET_SB;
sb[2] = telopt;
_sendu(telnet, sb, 3);
}
/****************************************************************************
* Name: telnet_subnegotiation
*
* Description:
* Send a complete subnegotiation buffer.
*
* Equivalent to:
* telnet_begin_sb(telnet, telopt);
* telnet_send(telnet, buffer, size);
* telnet_finish_sb(telnet);
*
* Input Parameters:
* telnet Telnet state tracker format.
* telopt One of the TELNET_TELOPT_* values.
* buffer Byte buffer for sub-negotiation data.
* size Number of bytes to use for sub-negotiation data.
*
****************************************************************************/
void telnet_subnegotiation(struct telnet_s *telnet, unsigned char telopt,
const char *buffer, size_t size)
{
unsigned char bytes[5];
bytes[0] = TELNET_IAC;
bytes[1] = TELNET_SB;
bytes[2] = telopt;
bytes[3] = TELNET_IAC;
bytes[4] = TELNET_SE;
_sendu(telnet, bytes, 3);
telnet_send(telnet, buffer, size);
_sendu(telnet, bytes + 3, 2);
#if defined(HAVE_ZLIB)
/* If we're a proxy and we just sent the COMPRESS2 marker, we must make sure
* all further data is compressed if not already.
*/
if (telnet->flags & TELNET_FLAG_PROXY && telopt == TELNET_TELOPT_COMPRESS2)
{
union telnet_event_u ev;
if (_init_zlib(telnet, 1, 1) != TELNET_EOK)
{
return;
}
/* Notify app that compression was enabled */
ev.type = TELNET_EV_COMPRESS;
ev.compress.state = 1;
telnet->eh(telnet, &ev, telnet->ud);
}
#endif /* HAVE_ZLIB */
}
/****************************************************************************
* Name: telnet_begin_compress2
*
* Description:
* Begin sending compressed data.
*
* This function will begein sending data using the COMPRESS2 option,
* which enables the use of zlib to compress data sent to the client.
* The client must offer support for COMPRESS2 with option negotiation,
* and zlib support must be compiled into libtelnet.
*
* Only the server may call this command.
*
* Input Parameters:
* telnet Telnet state tracker object.
*
****************************************************************************/
void telnet_begin_compress2(struct telnet_s *telnet)
{
#if defined(HAVE_ZLIB)
static const unsigned char compress2[] =
{
TELNET_IAC, TELNET_SB, TELNET_TELOPT_COMPRESS2, TELNET_IAC, TELNET_SE
};
union telnet_event_u ev;
/* Attempt to create output stream first, bail if we can't */
if (_init_zlib(telnet, 1, 0) != TELNET_EOK)
{
return;
}
/* Send compression marker. we send directly to the event handler instead of
* passing through _send because _send would result in the compress marker
* itself being compressed.
*/
ev.type = TELNET_EV_SEND;
ev.data.buffer = (const char *)compress2;
ev.data.size = sizeof(compress2);
telnet->eh(telnet, &ev, telnet->ud);
/* Notify app that compression was successfully enabled */
ev.type = TELNET_EV_COMPRESS;
ev.compress.state = 1;
telnet->eh(telnet, &ev, telnet->ud);
#endif /* HAVE_ZLIB */
}
/****************************************************************************
* Name: telnet_vprintf
*
* Description:
* Send formatted data with \r and \n translation in addition to IAC IAC
*
* See telnet_printf().
*
****************************************************************************/
int telnet_vprintf(struct telnet_s *telnet, const char *fmt, va_list va)
{
static const char CRLF[] = { '\r', '\n' };
static const char CRNUL[] = { '\r', '\0' };
char buffer[1024];
char *output = buffer;
int rs;
int l;
int i;
/* Format */
va_list va2;
va_copy(va2, va);
rs = vsnprintf(buffer, sizeof(buffer), fmt, va);
if (rs >= sizeof(buffer))
{
output = (char *)malloc(rs + 1);
if (output == 0)
{
_error(telnet, __LINE__, __func__, TELNET_ENOMEM, 0,
"malloc() failed: %d", errno);
return -1;
}
rs = vsnprintf(output, rs + 1, fmt, va2);
}
va_end(va2);
va_end(va);
/* Send */
for (l = i = 0; i != rs; ++i)
{
/* Special characters */
if (output[i] == (char)TELNET_IAC || output[i] == '\r' ||
output[i] == '\n')
{
/* Dump prior portion of text */
if (i != l)
{
_send(telnet, output + l, i - l);
}
l = i + 1;
/* IAC -> IAC IAC */
if (output[i] == (char)TELNET_IAC)
{
telnet_iac(telnet, TELNET_IAC);
}
/* Automatic translation of \r -> CRNUL */
else if (output[i] == '\r')
{
_send(telnet, CRNUL, 2);
}
/* Automatic translation of \n -> CRLF */
else if (output[i] == '\n')
{
_send(telnet, CRLF, 2);
}
}
}
/* Send whatever portion of output is left */
if (i != l)
{
_send(telnet, output + l, i - l);
}
/* Free allocated memory, if any */
if (output != buffer)
{
free(output);
}
return rs;
}
/****************************************************************************
* Name: telnet_printf
*
* Description:
* Send formatted data.
*
* This function is a wrapper around telnet_send(). It allows using
* printf-style formatting.
*
* Additionally, this function will translate \\r to the CR NUL construct
* and \\n with CR LF, as well as automatically escaping IAC bytes like
* telnet_send().
*
* Input Parameters:
* telnet Telnet state tracker object.
* fmt Format string.
*
* Returned Value:
* Number of bytes sent.
*
****************************************************************************/
int telnet_printf(struct telnet_s *telnet, const char *fmt, ...)
{
va_list va;
int rs;
va_start(va, fmt);
rs = telnet_vprintf(telnet, fmt, va);
va_end(va);
return rs;
}
/****************************************************************************
* Name: telnet_raw_vprintf
*
* Description:
* Send formatted data (no newline escaping).
*
* See telnet_raw_printf().
*
****************************************************************************/
int telnet_raw_vprintf(struct telnet_s *telnet, const char *fmt, va_list va)
{
char buffer[1024];
char *output = buffer;
int rs;
/* Format; allocate more space if necessary */
va_list va2;
va_copy(va2, va);
rs = vsnprintf(buffer, sizeof(buffer), fmt, va);
if (rs >= sizeof(buffer))
{
output = (char *)malloc(rs + 1);
if (output == 0)
{
_error(telnet, __LINE__, __func__, TELNET_ENOMEM, 0,
"malloc() failed: %d", errno);
return -1;
}
rs = vsnprintf(output, rs + 1, fmt, va2);
}
va_end(va2);
va_end(va);
/* Send out the formatted data */
telnet_send(telnet, output, rs);
/* Release allocated memory, if any */
if (output != buffer)
{
free(output);
}
return rs;
}
/****************************************************************************
* Name: telnet_raw_printf
*
* Description:
* Send formatted data (no newline escaping).
*
* This behaves identically to telnet_printf(), except that the \\r and \\n
* characters are not translated. The IAC byte is still escaped as normal
* with telnet_send().
*
* Input Parameters:
* telnet Telnet state tracker object.
* fmt Format string.
*
* Returned Value:
* Number of bytes sent.
*
****************************************************************************/
int telnet_raw_printf(struct telnet_s *telnet, const char *fmt, ...)
{
va_list va;
int rs;
va_start(va, fmt);
rs = telnet_raw_vprintf(telnet, fmt, va);
va_end(va);
return rs;
}
/****************************************************************************
* Name: telnet_begin_newenviron
*
* Description:
* Begin a new set of NEW-ENVIRON values to request or send.
*
* This function will begin the sub-negotiation block for sending or
* requesting NEW-ENVIRON values.
*
* The telnet_finish_newenviron() macro must be called after this
* function to terminate the NEW-ENVIRON command.
*
* Input Parameters:
* telnet Telnet state tracker object.
* type One of TELNET_ENVIRON_SEND, TELNET_ENVIRON_IS, or
* TELNET_ENVIRON_INFO.
*
****************************************************************************/
void telnet_begin_newenviron(struct telnet_s *telnet, unsigned char cmd)
{
telnet_begin_sb(telnet, TELNET_TELOPT_NEW_ENVIRON);
telnet_send(telnet, (const char *)&cmd, 1);
}
/****************************************************************************
* Name: telnet_newenviron_value
*
* Description:
* Send a NEW-ENVIRON variable name or value.
*
* This can only be called between calls to telnet_begin_newenviron() and
* telnet_finish_newenviron().
*
* Input Parameters:
* telnet Telnet state tracker object.
* type One of TELNET_ENVIRON_VAR, TELNET_ENVIRON_USERVAR, or
* TELNET_ENVIRON_VALUE.
* string Variable name or value.
*
****************************************************************************/
void telnet_newenviron_value(struct telnet_s *telnet, unsigned char type,
const char *string)
{
telnet_send(telnet, (const char *)&type, 1);
if (string != 0)
{
telnet_send(telnet, string, strlen(string));
}
}
/****************************************************************************
* Name: telnet_ttype_send
*
* Description:
* Send the TERMINAL-TYPE SEND command.
*
* Sends the sequence IAC TERMINAL-TYPE SEND.
*
* telnet Telnet state tracker object.
*
****************************************************************************/
void telnet_ttype_send(struct telnet_s *telnet)
{
static const unsigned char SEND[] =
{
TELNET_IAC, TELNET_SB, TELNET_TELOPT_TTYPE, TELNET_TTYPE_SEND,
TELNET_IAC, TELNET_SE
};
_sendu(telnet, SEND, sizeof(SEND));
}
/****************************************************************************
* Name: telnet_ttype_is
*
* Description:
* Send the TERMINAL-TYPE IS command.
*
* Sends the sequence IAC TERMINAL-TYPE IS "string".
*
* According to the RFC, the recipient of a TERMINAL-TYPE SEND shall
* send the next possible terminal-type the client supports. Upon sending
* the type, the client should switch modes to begin acting as the terminal
* type is just sent.
*
* The server may continue sending TERMINAL-TYPE IS until it receives a
* terminal type is understands. To indicate to the server that it has
* reached the end of the available optoins, the client must send the last
* terminal type a second time. When the server receives the same terminal
* type twice in a row, it knows it has seen all available terminal types.
*
* After the last terminal type is sent, if the client receives another
* TERMINAL-TYPE SEND command, it must begin enumerating the available
* terminal types from the very beginning. This allows the server to
* scan the available types for a preferred terminal type and, if none
* is found, to then ask the client to switch to an acceptable
* alternative.
*
* Note that if the client only supports a single terminal type, then
* simply sending that one type in response to every SEND will satisfy
* the behavior requirements.
*
* Input Parameters:
* telnet Telnet state tracker object.
* ttype Name of the terminal-type being sent.
*
****************************************************************************/
void telnet_ttype_is(struct telnet_s *telnet, const char *ttype)
{
static const unsigned char IS[] =
{
TELNET_IAC, TELNET_SB, TELNET_TELOPT_TTYPE, TELNET_TTYPE_IS
};
if (!ttype)
{
ttype = "NVT";
}
_sendu(telnet, IS, sizeof(IS));
_send(telnet, ttype, strlen(ttype));
telnet_finish_sb(telnet);
}
/****************************************************************************
* Name: telnet_send_zmp
*
* Description:
* Send a ZMP command.
*
* Input Parameters:
* telnet Telnet state tracker object.
* argc Number of ZMP commands being sent.
* argv Array of argument strings.
*
****************************************************************************/
void telnet_send_zmp(struct telnet_s *telnet, size_t argc, const char **argv)
{
size_t i;
/* ZMP header */
telnet_begin_zmp(telnet, argv[0]);
/* Send out each argument, including trailing NUL byte */
for (i = 1; i != argc; ++i)
{
telnet_zmp_arg(telnet, argv[i]);
}
/* ZMP footer */
telnet_finish_zmp(telnet);
}
/****************************************************************************
* Name: telnet_send_vzmpv
*
* Description:
* Send a ZMP command.
*
* See telnet_send_zmpv().
*
****************************************************************************/
void telnet_send_vzmpv(struct telnet_s *telnet, va_list va)
{
const char *arg;
/* ZMP header */
telnet_begin_sb(telnet, TELNET_TELOPT_ZMP);
/* Send out each argument, including trailing NUL byte */
while ((arg = va_arg(va, const char *)) != 0)
{
telnet_zmp_arg(telnet, arg);
}
/* ZMP footer */
telnet_finish_zmp(telnet);
}
/****************************************************************************
* Name: telnet_send_zmpv
*
* Description:
* Send a ZMP command.
*
* Arguments are listed out in var-args style. After the last argument, a
* NULL pointer must be passed in as a sentinel value.
*
* Input Parameters:
* telnet Telnet state tracker object.
*
****************************************************************************/
void telnet_send_zmpv(struct telnet_s *telnet, ...)
{
va_list va;
va_start(va, telnet);
telnet_send_vzmpv(telnet, va);
va_end(va);
}
/****************************************************************************
* Name: telnet_begin_zmp
*
* Description:
* Begin sending a ZMP command
*
* Input Parameters:
* telnet Telnet state tracker object.
* cmd The first argument (command name) for the ZMP command.
*
****************************************************************************/
void telnet_begin_zmp(struct telnet_s *telnet, const char *cmd)
{
telnet_begin_sb(telnet, TELNET_TELOPT_ZMP);
telnet_zmp_arg(telnet, cmd);
}
/****************************************************************************
* Name: telnet_zmp_arg
*
* Description:
* Send a ZMP command argument.
*
* Input Parameters:
* telnet Telnet state tracker object.
* arg Telnet argument string.
*
****************************************************************************/
void telnet_zmp_arg(struct telnet_s *telnet, const char *arg)
{
telnet_send(telnet, arg, strlen(arg) + 1);
}
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