mirror of https://gerrit.osmocom.org/libtelnet
922 lines
23 KiB
C
922 lines
23 KiB
C
/*
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* Sean Middleditch
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* sean@sourcemud.org
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*
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* The author or authors of this code dedicate any and all copyright interest
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* in this code to the public domain. We make this dedication for the benefit
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* of the public at large and to the detriment of our heirs and successors. We
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* intend this dedication to be an overt act of relinquishment in perpetuity of
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* all present and future rights to this code under copyright law.
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*/
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#include <malloc.h>
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#include <string.h>
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#include <stdio.h>
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#include <errno.h>
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#include <string.h>
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#include <stdarg.h>
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#ifdef HAVE_ZLIB
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#include "zlib.h"
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#endif
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#include "libtelnet.h"
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/* RFC1143 state names */
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#define RFC1143_NO 0x00
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#define RFC1143_YES 0x01
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#define RFC1143_WANT 0x02
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#define RFC1143_OP 0x04
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#define RFC1143_WANTNO (RFC1143_WANT|RFC1143_YES)
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#define RFC1143_WANTYES (RFC1143_WANT|RFC1143_NO)
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#define RFC1143_WANTNO_OP (RFC1143_WANTNO|RFC1143_OP)
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#define RFC1143_WANTYES_OP (RFC1143_WANTYES|RFC1143_OP)
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/* buffer sizes */
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static const size_t _buffer_sizes[] = {
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0,
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512,
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2048,
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8192,
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16384,
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};
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static const size_t _buffer_sizes_count = sizeof(_buffer_sizes) /
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sizeof(_buffer_sizes[0]);
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/* event dispatch helper; return value is value of the accept field of the
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* event struct after dispatch; used for the funky REQUEST event */
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static int _event(telnet_t *telnet, telnet_event_type_t type,
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unsigned char command, unsigned char telopt,
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const char *buffer, size_t size) {
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telnet_event_t ev;
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ev.buffer = buffer;
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ev.size = size;
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ev.type = type;
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ev.command = command;
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ev.telopt = telopt;
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ev.accept = 0;
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telnet->eh(telnet, &ev, telnet->ud);
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return ev.accept;
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}
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/* error generation function */
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static telnet_error_t _error(telnet_t *telnet, unsigned line,
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const char* func, telnet_error_t err, int fatal, const char *fmt,
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...) {
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char buffer[512];
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va_list va;
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/* format error intro */
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snprintf(buffer, sizeof(buffer), "%s:%u in %s: ", __FILE__, line, func);
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va_start(va, fmt);
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vsnprintf(buffer + strlen(buffer), sizeof(buffer) - strlen(buffer),
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fmt, va);
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va_end(va);
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_event(telnet, fatal ? TELNET_EV_ERROR : TELNET_EV_WARNING, err,
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0, (char *)buffer, strlen(buffer));
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return err;
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}
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#ifdef HAVE_ZLIB
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/* initialize the zlib box for a telnet box; if deflate is non-zero, it
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* initializes zlib for delating (compression), otherwise for inflating
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* (decompression). returns TELNET_EOK on success, something else on
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* failure.
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*/
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telnet_error_t _init_zlib(telnet_t *telnet, int deflate, int err_fatal) {
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z_stream *z;
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int rs;
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/* if compression is already enabled, fail loudly */
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if (telnet->z != 0)
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return _error(telnet, __LINE__, __func__, TELNET_EBADVAL,
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err_fatal, "cannot initialize compression twice");
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/* allocate zstream box */
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if ((z= (z_stream *)calloc(1, sizeof(z_stream))) == 0)
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return _error(telnet, __LINE__, __func__, TELNET_ENOMEM, err_fatal,
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"malloc() failed: %s", strerror(errno));
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/* initialize */
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if (deflate) {
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if ((rs = deflateInit(z, Z_DEFAULT_COMPRESSION)) != Z_OK) {
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free(z);
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return _error(telnet, __LINE__, __func__, TELNET_ECOMPRESS,
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err_fatal, "deflateInit() failed: %s", zError(rs));
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}
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telnet->flags |= TELNET_PFLAG_DEFLATE;
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} else {
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if ((rs = inflateInit(z)) != Z_OK) {
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free(z);
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return _error(telnet, __LINE__, __func__, TELNET_ECOMPRESS,
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err_fatal, "inflateInit() failed: %s", zError(rs));
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}
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telnet->flags &= ~TELNET_PFLAG_DEFLATE;
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}
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telnet->z = z;
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return TELNET_EOK;
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}
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#endif
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/* push bytes out, compressing them first if need be */
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static void _send(telnet_t *telnet, const char *buffer,
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size_t size) {
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#ifdef HAVE_ZLIB
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/* if we have a deflate (compression) zlib box, use it */
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if (telnet->z != 0 && telnet->flags & TELNET_PFLAG_DEFLATE) {
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char deflate_buffer[1024];
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int rs;
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/* initialize z state */
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telnet->z->next_in = (unsigned char *)buffer;
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telnet->z->avail_in = size;
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telnet->z->next_out = (unsigned char *)deflate_buffer;
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telnet->z->avail_out = sizeof(deflate_buffer);
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/* deflate until buffer exhausted and all output is produced */
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while (telnet->z->avail_in > 0 || telnet->z->avail_out == 0) {
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/* compress */
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if ((rs = deflate(telnet->z, Z_SYNC_FLUSH)) != Z_OK) {
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_error(telnet, __LINE__, __func__, TELNET_ECOMPRESS, 1,
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"deflate() failed: %s", zError(rs));
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deflateEnd(telnet->z);
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free(telnet->z);
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telnet->z = 0;
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break;
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}
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_event(telnet, TELNET_EV_SEND, 0, 0, deflate_buffer,
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sizeof(deflate_buffer) - telnet->z->avail_out);
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/* prepare output buffer for next run */
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telnet->z->next_out = (unsigned char *)deflate_buffer;
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telnet->z->avail_out = sizeof(deflate_buffer);
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}
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/* COMPRESS2 is not negotiated, just send */
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} else
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#endif /* HAVE_ZLIB */
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_event(telnet, TELNET_EV_SEND, 0, 0, buffer, size);
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}
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/* retrieve RFC1143 option state */
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telnet_rfc1143_t _get_rfc1143(telnet_t *telnet, unsigned char telopt) {
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static const telnet_rfc1143_t empty = { 0, 0, 0};
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int i;
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/* search for entry */
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for (i = 0; i != telnet->q_size; ++i)
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if (telnet->q[i].telopt == telopt)
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return telnet->q[i];
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/* not found, return empty value */
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return empty;
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}
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/* save RFC1143 option state */
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void _set_rfc1143(telnet_t *telnet, telnet_rfc1143_t q) {
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telnet_rfc1143_t *qtmp;
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int i;
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/* search for entry */
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for (i = 0; i != telnet->q_size; ++i) {
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if (telnet->q[i].telopt == q.telopt) {
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telnet->q[i] = q;
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return;
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}
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}
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/* we're going to need to track state for it, so grow the queue
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* and put the telopt into it; bail on allocation error
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*/
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if ((qtmp = (telnet_rfc1143_t *)malloc(sizeof(
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telnet_rfc1143_t) * (telnet->q_size + 1))) == 0) {
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_error(telnet, __LINE__, __func__, TELNET_ENOMEM, 0,
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"malloc() failed: %s", strerror(errno));
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return;
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}
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telnet->q = qtmp;
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telnet->q[telnet->q_size++] = q;
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}
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/* negotiation handling magic for RFC1143 */
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static void _negotiate(telnet_t *telnet, unsigned char cmd,
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unsigned char telopt) {
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telnet_rfc1143_t q;
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/* in PROXY mode, just pass it thru and do nothing */
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if (telnet->flags & TELNET_FLAG_PROXY) {
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switch (cmd) {
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case TELNET_WILL:
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_event(telnet, TELNET_EV_WILL, 0, telopt, 0, 0);
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break;
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case TELNET_WONT:
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_event(telnet, TELNET_EV_WONT, 0, telopt, 0, 0);
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break;
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case TELNET_DO:
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_event(telnet, TELNET_EV_DO, 0, telopt, 0, 0);
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break;
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case TELNET_DONT:
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_event(telnet, TELNET_EV_DONT, 0, telopt, 0, 0);
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break;
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}
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return;
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}
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/* lookup the current state of the option */
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q = _get_rfc1143(telnet, telopt);
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/* start processing... */
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switch (cmd) {
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/* request to enable option on remote end or confirm DO */
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case TELNET_WILL:
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switch (q.him) {
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case RFC1143_NO:
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if (_event(telnet, TELNET_EV_WILL, cmd, telopt, 0, 0) == 1) {
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q.him = RFC1143_YES;
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_set_rfc1143(telnet, q);
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telnet_send_telopt(telnet, TELNET_DO, telopt);
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} else
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telnet_send_telopt(telnet, TELNET_DONT, telopt);
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break;
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case RFC1143_YES:
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break;
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case RFC1143_WANTNO:
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q.him = RFC1143_NO;
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_set_rfc1143(telnet, q);
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_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
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"DONT answered by WILL");
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break;
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case RFC1143_WANTNO_OP:
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q.him = RFC1143_YES;
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_set_rfc1143(telnet, q);
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_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
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"DONT answered by WILL");
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break;
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case RFC1143_WANTYES:
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q.him = RFC1143_YES;
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_set_rfc1143(telnet, q);
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break;
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case RFC1143_WANTYES_OP:
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q.him = RFC1143_WANTNO;
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_set_rfc1143(telnet, q);
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telnet_send_telopt(telnet, TELNET_DONT, telopt);
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break;
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}
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break;
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/* request to disable option on remote end, confirm DONT, reject DO */
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case TELNET_WONT:
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switch (q.him) {
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case RFC1143_NO:
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break;
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case RFC1143_YES:
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q.him = RFC1143_NO;
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_set_rfc1143(telnet, q);
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telnet_send_telopt(telnet, TELNET_DONT, telopt);
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_event(telnet, TELNET_EV_WONT, 0, telopt,
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0, 0);
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break;
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case RFC1143_WANTNO:
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q.him = RFC1143_NO;
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_set_rfc1143(telnet, q);
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_event(telnet, TELNET_EV_WONT, 0, telopt,
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0, 0);
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break;
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case RFC1143_WANTNO_OP:
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q.him = RFC1143_WANTYES;
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_set_rfc1143(telnet, q);
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_event(telnet, TELNET_EV_DO, 0, telopt,
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0, 0);
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break;
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case RFC1143_WANTYES:
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case RFC1143_WANTYES_OP:
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q.him = RFC1143_NO;
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_set_rfc1143(telnet, q);
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break;
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}
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break;
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/* request to enable option on local end or confirm WILL */
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case TELNET_DO:
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switch (q.us) {
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case RFC1143_NO:
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if (_event(telnet, TELNET_EV_DO, cmd, telopt, 0, 0) == 1) {
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q.us = RFC1143_YES;
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_set_rfc1143(telnet, q);
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telnet_send_telopt(telnet, TELNET_WILL, telopt);
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} else
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telnet_send_telopt(telnet, TELNET_WONT, telopt);
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break;
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case RFC1143_YES:
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break;
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case RFC1143_WANTNO:
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q.us = RFC1143_NO;
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_set_rfc1143(telnet, q);
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_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
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"WONT answered by DO");
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break;
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case RFC1143_WANTNO_OP:
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q.us = RFC1143_YES;
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_set_rfc1143(telnet, q);
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_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
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"WONT answered by DO");
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break;
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case RFC1143_WANTYES:
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q.us = RFC1143_YES;
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_set_rfc1143(telnet, q);
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break;
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case RFC1143_WANTYES_OP:
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q.us = RFC1143_WANTNO;
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_set_rfc1143(telnet, q);
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telnet_send_telopt(telnet, TELNET_WONT, telopt);
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break;
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}
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break;
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/* request to disable option on local end, confirm WONT, reject WILL */
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case TELNET_DONT:
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switch (q.us) {
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case RFC1143_NO:
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break;
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case RFC1143_YES:
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q.us = RFC1143_NO;
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_set_rfc1143(telnet, q);
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telnet_send_telopt(telnet, TELNET_WONT, telopt);
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_event(telnet, TELNET_EV_DONT, 0, telopt, 0, 0);
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break;
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case RFC1143_WANTNO:
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q.us = RFC1143_NO;
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_set_rfc1143(telnet, q);
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_event(telnet, TELNET_EV_WONT, 0, telopt, 0, 0);
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break;
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case RFC1143_WANTNO_OP:
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q.us = RFC1143_WANTYES;
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_set_rfc1143(telnet, q);
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_event(telnet, TELNET_EV_WILL, 0, telopt, 0, 0);
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break;
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case RFC1143_WANTYES:
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case RFC1143_WANTYES_OP:
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q.us = RFC1143_NO;
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_set_rfc1143(telnet, q);
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break;
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}
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break;
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}
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}
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/* initialize a telnet state tracker */
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void telnet_init(telnet_t *telnet, telnet_event_handler_t eh,
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unsigned char flags, void *user_data) {
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memset(telnet, 0, sizeof(telnet_t));
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telnet->ud = user_data;
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telnet->eh = eh;
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telnet->flags = flags;
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}
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/* free up any memory allocated by a state tracker */
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void telnet_free(telnet_t *telnet) {
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/* free sub-request buffer */
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if (telnet->buffer != 0) {
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free(telnet->buffer);
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telnet->buffer = 0;
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telnet->buffer_size = 0;
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telnet->buffer_pos = 0;
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}
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#ifdef HAVE_ZLIB
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/* free zlib box */
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if (telnet->z != 0) {
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if (telnet->flags & TELNET_PFLAG_DEFLATE)
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deflateEnd(telnet->z);
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else
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inflateEnd(telnet->z);
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free(telnet->z);
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telnet->z = 0;
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}
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#endif
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/* free RFC1143 queue */
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if (telnet->q) {
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free(telnet->q);
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telnet->q = 0;
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telnet->q_size = 0;
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}
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}
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/* push a byte into the telnet buffer */
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static telnet_error_t _buffer_byte(telnet_t *telnet,
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unsigned char byte) {
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char *new_buffer;
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size_t i;
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/* check if we're out of room */
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if (telnet->buffer_pos == telnet->buffer_size) {
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/* find the next buffer size */
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for (i = 0; i != _buffer_sizes_count; ++i) {
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if (_buffer_sizes[i] == telnet->buffer_size)
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break;
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}
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/* overflow -- can't grow any more */
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if (i >= _buffer_sizes_count - 1) {
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_error(telnet, __LINE__, __func__, TELNET_EOVERFLOW, 0,
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"subnegotiation buffer size limit reached");
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telnet_free(telnet);
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return TELNET_EOVERFLOW;
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}
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/* (re)allocate buffer */
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new_buffer = (char *)realloc(telnet->buffer,
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_buffer_sizes[i + 1]);
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if (new_buffer == 0) {
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_error(telnet, __LINE__, __func__, TELNET_ENOMEM, 0,
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"realloc() failed");
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telnet_free(telnet);
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return TELNET_ENOMEM;
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}
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telnet->buffer = new_buffer;
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telnet->buffer_size = _buffer_sizes[i + 1];
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}
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/* push the byte, all set */
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telnet->buffer[telnet->buffer_pos++] = byte;
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return TELNET_EOK;
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}
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|
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static void _process(telnet_t *telnet, const char *buffer,
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size_t size) {
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unsigned char byte;
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size_t i, start;
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for (i = start = 0; i != size; ++i) {
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byte = buffer[i];
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switch (telnet->state) {
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/* regular data */
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case TELNET_STATE_DATA:
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/* on an IAC byte, pass through all pending bytes and
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* switch states */
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if (byte == TELNET_IAC) {
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if (i != start)
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_event(telnet, TELNET_EV_DATA, 0, 0, &buffer[start],
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i - start);
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telnet->state = TELNET_STATE_IAC;
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}
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break;
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/* IAC command */
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case TELNET_STATE_IAC:
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switch (byte) {
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/* subnegotiation */
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case TELNET_SB:
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telnet->state = TELNET_STATE_SB;
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break;
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/* negotiation commands */
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case TELNET_WILL:
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telnet->state = TELNET_STATE_WILL;
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break;
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case TELNET_WONT:
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telnet->state = TELNET_STATE_WONT;
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break;
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|
case TELNET_DO:
|
|
telnet->state = TELNET_STATE_DO;
|
|
break;
|
|
case TELNET_DONT:
|
|
telnet->state = TELNET_STATE_DONT;
|
|
break;
|
|
/* IAC escaping */
|
|
case TELNET_IAC:
|
|
_event(telnet, TELNET_EV_DATA, 0, 0, (char*)&byte, 1);
|
|
start = i + 1;
|
|
telnet->state = TELNET_STATE_DATA;
|
|
break;
|
|
/* some other command */
|
|
default:
|
|
_event(telnet, TELNET_EV_IAC, byte, 0, 0, 0);
|
|
start = i + 1;
|
|
telnet->state = TELNET_STATE_DATA;
|
|
}
|
|
break;
|
|
|
|
/* negotiation commands */
|
|
case TELNET_STATE_DO:
|
|
_negotiate(telnet, TELNET_DO, byte);
|
|
start = i + 1;
|
|
telnet->state = TELNET_STATE_DATA;
|
|
break;
|
|
case TELNET_STATE_DONT:
|
|
_negotiate(telnet, TELNET_DONT, byte);
|
|
start = i + 1;
|
|
telnet->state = TELNET_STATE_DATA;
|
|
break;
|
|
case TELNET_STATE_WILL:
|
|
_negotiate(telnet, TELNET_WILL, byte);
|
|
start = i + 1;
|
|
telnet->state = TELNET_STATE_DATA;
|
|
break;
|
|
case TELNET_STATE_WONT:
|
|
_negotiate(telnet, TELNET_WONT, 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;
|
|
/* 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;
|
|
|
|
/* invoke callback */
|
|
_event(telnet, TELNET_EV_SUBNEGOTIATION, 0,
|
|
telnet->sb_telopt, telnet->buffer, telnet->buffer_pos);
|
|
|
|
#ifdef HAVE_ZLIB
|
|
/* received COMPRESS2 begin marker, setup our zlib box and
|
|
* start handling the compressed stream if it's not already.
|
|
*/
|
|
if (telnet->sb_telopt == TELNET_TELOPT_COMPRESS2) {
|
|
if (_init_zlib(telnet, 0, 1) != TELNET_EOK)
|
|
break;
|
|
|
|
/* notify app that compression was enabled */
|
|
_event(telnet, TELNET_EV_COMPRESS, 1, 0, 0, 0);
|
|
|
|
/* any remaining bytes in the buffer are compressed.
|
|
* we have to re-invoke telnet_push to get those
|
|
* bytes inflated and abort trying to process the
|
|
* remaining compressed bytes in the current _process
|
|
* buffer argument
|
|
*/
|
|
telnet_push(telnet, &buffer[start], size - start);
|
|
return;
|
|
}
|
|
#endif /* HAVE_ZLIB */
|
|
|
|
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 */
|
|
default:
|
|
_error(telnet, __LINE__, __func__, TELNET_EPROTOCOL, 0,
|
|
"unexpected byte after IAC inside SB: %d",
|
|
byte);
|
|
start = i + 1;
|
|
telnet->state = TELNET_STATE_DATA;
|
|
break;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* pass through any remaining bytes */
|
|
if (telnet->state == TELNET_STATE_DATA && i != start)
|
|
_event(telnet, TELNET_EV_DATA, 0, 0, buffer + start, i - start);
|
|
}
|
|
|
|
/* push a bytes into the state tracker */
|
|
void telnet_push(telnet_t *telnet, const char *buffer,
|
|
size_t size) {
|
|
#ifdef HAVE_ZLIB
|
|
/* if we have an inflate (decompression) zlib stream, use it */
|
|
if (telnet->z != 0 && !(telnet->flags & TELNET_PFLAG_DEFLATE)) {
|
|
char inflate_buffer[4096];
|
|
int rs;
|
|
|
|
/* initialize zlib state */
|
|
telnet->z->next_in = (unsigned char*)buffer;
|
|
telnet->z->avail_in = 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) {
|
|
_event(telnet, TELNET_EV_COMPRESS, 0, 0, 0, 0);
|
|
|
|
inflateEnd(telnet->z);
|
|
free(telnet->z);
|
|
telnet->z = 0;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* COMPRESS2 is not negotiated, just process */
|
|
} else
|
|
#endif /* HAVE_ZLIB */
|
|
_process(telnet, buffer, size);
|
|
}
|
|
|
|
/* send an iac command */
|
|
void telnet_send_command(telnet_t *telnet, unsigned char cmd) {
|
|
char bytes[2] = { TELNET_IAC, cmd };
|
|
_send(telnet, bytes, 2);
|
|
}
|
|
|
|
/* send an iac command with telopt */
|
|
void telnet_send_telopt(telnet_t *telnet, unsigned char cmd,
|
|
unsigned char telopt) {
|
|
char bytes[3] = { TELNET_IAC, cmd, telopt };
|
|
_send(telnet, bytes, 3);
|
|
}
|
|
|
|
/* send negotiation */
|
|
void telnet_send_negotiate(telnet_t *telnet, unsigned char cmd,
|
|
unsigned char telopt) {
|
|
telnet_rfc1143_t q;
|
|
|
|
/* if we're in proxy mode, just send it now */
|
|
if (telnet->flags & TELNET_FLAG_PROXY) {
|
|
char bytes[3] = { TELNET_IAC, cmd, telopt };
|
|
_send(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) {
|
|
case RFC1143_NO:
|
|
q.us = RFC1143_WANTYES;
|
|
_set_rfc1143(telnet, q);
|
|
_negotiate(telnet, TELNET_WILL, telopt);
|
|
break;
|
|
case RFC1143_YES:
|
|
break;
|
|
case RFC1143_WANTNO:
|
|
q.us = RFC1143_WANTNO_OP;
|
|
_set_rfc1143(telnet, q);
|
|
break;
|
|
case RFC1143_WANTYES:
|
|
break;
|
|
case RFC1143_WANTNO_OP:
|
|
break;
|
|
case RFC1143_WANTYES_OP:
|
|
q.us = RFC1143_WANTYES;
|
|
_set_rfc1143(telnet, q);
|
|
break;
|
|
}
|
|
break;
|
|
|
|
/* force turn-off of locally enabled option */
|
|
case TELNET_WONT:
|
|
switch (q.us) {
|
|
case RFC1143_NO:
|
|
break;
|
|
case RFC1143_YES:
|
|
q.us = RFC1143_WANTNO;
|
|
_set_rfc1143(telnet, q);
|
|
_negotiate(telnet, TELNET_WONT, telopt);
|
|
break;
|
|
case RFC1143_WANTNO:
|
|
break;
|
|
case RFC1143_WANTYES:
|
|
q.us = RFC1143_WANTYES_OP;
|
|
_set_rfc1143(telnet, q);
|
|
break;
|
|
case RFC1143_WANTNO_OP:
|
|
q.us = RFC1143_WANTNO;
|
|
_set_rfc1143(telnet, q);
|
|
break;
|
|
case RFC1143_WANTYES_OP:
|
|
break;
|
|
}
|
|
break;
|
|
|
|
/* ask remote end to enable an option */
|
|
case TELNET_DO:
|
|
switch (q.him) {
|
|
case RFC1143_NO:
|
|
q.him = RFC1143_WANTYES;
|
|
_set_rfc1143(telnet, q);
|
|
_negotiate(telnet, TELNET_DO, telopt);
|
|
break;
|
|
case RFC1143_YES:
|
|
break;
|
|
case RFC1143_WANTNO:
|
|
q.him = RFC1143_WANTNO_OP;
|
|
_set_rfc1143(telnet, q);
|
|
break;
|
|
case RFC1143_WANTYES:
|
|
break;
|
|
case RFC1143_WANTNO_OP:
|
|
break;
|
|
case RFC1143_WANTYES_OP:
|
|
q.him = RFC1143_WANTYES;
|
|
_set_rfc1143(telnet, q);
|
|
break;
|
|
}
|
|
break;
|
|
|
|
/* demand remote end disable an option */
|
|
case TELNET_DONT:
|
|
switch (q.him) {
|
|
case RFC1143_NO:
|
|
break;
|
|
case RFC1143_YES:
|
|
q.him = RFC1143_WANTNO;
|
|
_set_rfc1143(telnet, q);
|
|
_negotiate(telnet, TELNET_DONT, telopt);
|
|
break;
|
|
case RFC1143_WANTNO:
|
|
break;
|
|
case RFC1143_WANTYES:
|
|
q.him = RFC1143_WANTYES_OP;
|
|
_set_rfc1143(telnet, q);
|
|
break;
|
|
case RFC1143_WANTNO_OP:
|
|
q.him = RFC1143_WANTNO;
|
|
_set_rfc1143(telnet, q);
|
|
break;
|
|
case RFC1143_WANTYES_OP:
|
|
break;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* send non-command data (escapes IAC bytes) */
|
|
void telnet_send_data(telnet_t *telnet, const char *buffer,
|
|
size_t size) {
|
|
size_t i, l;
|
|
|
|
for (l = i = 0; i != size; ++i) {
|
|
/* dump prior portion of text, send escaped bytes */
|
|
if (buffer[i] == TELNET_IAC) {
|
|
/* dump prior text if any */
|
|
if (i != l)
|
|
_send(telnet, buffer + l, i - l);
|
|
l = i + 1;
|
|
|
|
/* send escape */
|
|
telnet_send_command(telnet, TELNET_IAC);
|
|
}
|
|
}
|
|
|
|
/* send whatever portion of buffer is left */
|
|
if (i != l)
|
|
_send(telnet, buffer + l, i - l);
|
|
}
|
|
|
|
/* send sub-request */
|
|
void telnet_send_subnegotiation(telnet_t *telnet, unsigned char telopt,
|
|
const char *buffer, size_t size) {
|
|
telnet_send_telopt(telnet, TELNET_SB, telopt);
|
|
telnet_send_data(telnet, buffer, size);
|
|
telnet_send_command(telnet, TELNET_SE);
|
|
|
|
#ifdef 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) {
|
|
|
|
if (_init_zlib(telnet, 1, 1) != TELNET_EOK)
|
|
return;
|
|
|
|
/* notify app that compression was enabled */
|
|
_event(telnet, TELNET_EV_COMPRESS, 1, 0, 0, 0);
|
|
}
|
|
#endif /* HAVE_ZLIB */
|
|
}
|
|
|
|
void telnet_begin_compress2(telnet_t *telnet) {
|
|
#ifdef HAVE_ZLIB
|
|
static const char compress2[] = { TELNET_IAC, TELNET_SB,
|
|
TELNET_TELOPT_COMPRESS2, TELNET_IAC, TELNET_SE };
|
|
|
|
/* 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.
|
|
*/
|
|
_event(telnet, TELNET_EV_SEND, 0, 0, compress2, sizeof(compress2));
|
|
|
|
/* notify app that compression was successfully enabled */
|
|
_event(telnet, TELNET_EV_COMPRESS, 1, 0, 0, 0);
|
|
#endif /* HAVE_ZLIB */
|
|
}
|
|
|
|
/* send formatted data with \r and \n translation in addition to IAC IAC */
|
|
int telnet_printf(telnet_t *telnet, const char *fmt, ...) {
|
|
static const char CRLF[] = { '\r', '\n' };
|
|
static const char CRNUL[] = { '\r', '\0' };
|
|
char buffer[4096];
|
|
va_list va;
|
|
int rs, i, l;
|
|
|
|
/* format */
|
|
va_start(va, fmt);
|
|
rs = vsnprintf(buffer, sizeof(buffer), fmt, va);
|
|
va_end(va);
|
|
|
|
/* send */
|
|
for (l = i = 0; i != rs; ++i) {
|
|
/* special characters */
|
|
if (buffer[i] == TELNET_IAC || buffer[i] == '\r' ||
|
|
buffer[i] == '\n') {
|
|
/* dump prior portion of text */
|
|
if (i != l)
|
|
_send(telnet, (char *)buffer + l, i - l);
|
|
l = i + 1;
|
|
|
|
/* IAC -> IAC IAC */
|
|
if (buffer[i] == TELNET_IAC)
|
|
telnet_send_command(telnet, TELNET_IAC);
|
|
/* automatic translation of \r -> CRNUL */
|
|
else if (buffer[i] == '\r')
|
|
_send(telnet, CRNUL, 2);
|
|
/* automatic translation of \n -> CRLF */
|
|
else if (buffer[i] == '\n')
|
|
_send(telnet, CRLF, 2);
|
|
}
|
|
}
|
|
|
|
/* send whatever portion of buffer is left */
|
|
if (i != l)
|
|
_send(telnet, (char *)buffer + l, i - l);
|
|
|
|
return rs;
|
|
}
|
|
|
|
/* send formatted data through telnet_send_data */
|
|
int telnet_printf2(telnet_t *telnet, const char *fmt, ...) {
|
|
char buffer[4096];
|
|
va_list va;
|
|
int rs;
|
|
|
|
/* format */
|
|
va_start(va, fmt);
|
|
rs = vsnprintf(buffer, sizeof(buffer), fmt, va);
|
|
va_end(va);
|
|
|
|
/* send */
|
|
telnet_send_data(telnet, (char *)buffer, rs);
|
|
|
|
return rs;
|
|
}
|