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nuttx-apps/netutils/telnetc/telnetc.c

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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_u _error(struct telnet_s *telnet, unsigned line,
const char *func, enum telnet_error_u 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_u _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 unti 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 1;
}
/* 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 1;
}
/* 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 (telnet->sb_telopt == 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;
}
return 0;
#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_u _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
};
_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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