curl/lib/telnet.c
2001-03-05 14:52:23 +00:00

1109 lines
26 KiB
C

/*****************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 2000, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* In order to be useful for every potential user, curl and libcurl are
* dual-licensed under the MPL and the MIT/X-derivate licenses.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the MPL or the MIT/X-derivate
* licenses. You may pick one of these licenses.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* $Id$
*****************************************************************************/
#include "setup.h"
/* -- WIN32 approved -- */
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <stdlib.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__)
#include <winsock.h>
#include <time.h>
#include <io.h>
#else
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#include <netinet/in.h>
#include <sys/time.h>
#include <sys/resource.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <netdb.h>
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_NET_IF_H
#include <net/if.h>
#endif
#include <sys/ioctl.h>
#include <signal.h>
#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#endif
#include "urldata.h"
#include <curl/curl.h>
#include "transfer.h"
#include "sendf.h"
#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>
#define TELOPTS
#define TELCMDS
#include "arpa_telnet.h"
#define SUBBUFSIZE 512
#define SB_CLEAR(x) x->subpointer = x->subbuffer;
#define SB_TERM(x) { x->subend = x->subpointer; SB_CLEAR(x); }
#define SB_ACCUM(x,c) if (x->subpointer < (x->subbuffer+sizeof x->subbuffer)) { \
*x->subpointer++ = (c); \
}
#define SB_GET(x) ((*x->subpointer++)&0xff)
#define SB_PEEK(x) ((*x->subpointer)&0xff)
#define SB_EOF(x) (x->subpointer >= x->subend)
#define SB_LEN(x) (x->subend - x->subpointer)
static
void telrcv(struct connectdata *,
unsigned char *inbuf, /* Data received from socket */
int count); /* Number of bytes received */
static void printoption(struct UrlData *data,
const char *direction,
int cmd, int option);
static void negotiate(struct connectdata *);
static void send_negotiation(struct connectdata *, int cmd, int option);
static void set_local_option(struct connectdata *, int cmd, int option);
static void set_remote_option(struct connectdata *, int cmd, int option);
static void printsub(struct UrlData *data,
int direction, unsigned char *pointer, int length);
static void suboption(struct connectdata *);
/* For negotiation compliant to RFC 1143 */
#define NO 0
#define YES 1
#define WANTYES 2
#define WANTNO 3
#define EMPTY 0
#define OPPOSITE 1
/*
* Telnet receiver states for fsm
*/
typedef enum
{
TS_DATA = 0,
TS_IAC,
TS_WILL,
TS_WONT,
TS_DO,
TS_DONT,
TS_CR,
TS_SB, /* sub-option collection */
TS_SE /* looking for sub-option end */
} TelnetReceive;
struct TELNET {
int please_negotiate;
int already_negotiated;
int us[256];
int usq[256];
int us_preferred[256];
int him[256];
int himq[256];
int him_preferred[256];
char *subopt_ttype; /* Set with suboption TTYPE */
char *subopt_xdisploc; /* Set with suboption XDISPLOC */
struct curl_slist *telnet_vars; /* Environment variables */
/* suboptions */
char subbuffer[SUBBUFSIZE];
char *subpointer, *subend; /* buffer for sub-options */
TelnetReceive telrcv_state;
};
static
CURLcode init_telnet(struct connectdata *conn)
{
struct TELNET *tn;
tn = (struct TELNET *)malloc(sizeof(struct TELNET));
if(!tn)
return CURLE_OUT_OF_MEMORY;
conn->proto.telnet = (void *)tn; /* make us known */
memset(tn, 0, sizeof(struct TELNET));
tn->telrcv_state = TS_DATA;
/* Init suboptions */
SB_CLEAR(tn);
/* Set all options to NO */
#if 0
/* NO is zero => default fill pattern */
memset(tn->us, NO, 256);
memset(tn->usq, NO, 256);
memset(tn->us_preferred, NO, 256);
memset(tn->him, NO, 256);
memset(tn->himq, NO, 256);
memset(tn->him_preferred, NO, 256);
#endif
/* Set the options we want by default */
tn->us_preferred[TELOPT_BINARY] = YES;
tn->us_preferred[TELOPT_SGA] = YES;
tn->him_preferred[TELOPT_BINARY] = YES;
tn->him_preferred[TELOPT_SGA] = YES;
return CURLE_OK;
}
static void negotiate(struct connectdata *conn)
{
int i;
struct TELNET *tn = (struct TELNET *)conn->proto.telnet;
for(i = 0;i < NTELOPTS;i++)
{
if(tn->us_preferred[i] == YES)
set_local_option(conn, i, YES);
if(tn->him_preferred[i] == YES)
set_remote_option(conn, i, YES);
}
}
static void printoption(struct UrlData *data,
const char *direction, int cmd, int option)
{
char *fmt;
char *opt;
if (data->bits.verbose)
{
if (cmd == IAC)
{
if (TELCMD_OK(option))
printf("%s IAC %s\n", direction, TELCMD(option));
else
printf("%s IAC %d\n", direction, option);
}
else
{
fmt = (cmd == WILL) ? "WILL" : (cmd == WONT) ? "WONT" :
(cmd == DO) ? "DO" : (cmd == DONT) ? "DONT" : 0;
if (fmt)
{
if (TELOPT_OK(option))
opt = TELOPT(option);
else if (option == TELOPT_EXOPL)
opt = "EXOPL";
else
opt = NULL;
if(opt)
printf("%s %s %s\n", direction, fmt, opt);
else
printf("%s %s %d\n", direction, fmt, option);
}
else
printf("%s %d %d\n", direction, cmd, option);
}
}
}
static void send_negotiation(struct connectdata *conn, int cmd, int option)
{
unsigned char buf[3];
buf[0] = IAC;
buf[1] = cmd;
buf[2] = option;
swrite(conn->firstsocket, buf, 3);
printoption(conn->data, "SENT", cmd, option);
}
static
void set_remote_option(struct connectdata *conn, int option, int newstate)
{
struct TELNET *tn = (struct TELNET *)conn->proto.telnet;
if(newstate == YES)
{
switch(tn->him[option])
{
case NO:
tn->him[option] = WANTYES;
send_negotiation(conn, DO, option);
break;
case YES:
/* Already enabled */
break;
case WANTNO:
switch(tn->himq[option])
{
case EMPTY:
/* Already negotiating for YES, queue the request */
tn->himq[option] = OPPOSITE;
break;
case OPPOSITE:
/* Error: already queued an enable request */
break;
}
break;
case WANTYES:
switch(tn->himq[option])
{
case EMPTY:
/* Error: already negotiating for enable */
break;
case OPPOSITE:
tn->himq[option] = EMPTY;
break;
}
break;
}
}
else /* NO */
{
switch(tn->him[option])
{
case NO:
/* Already disabled */
break;
case YES:
tn->him[option] = WANTNO;
send_negotiation(conn, DONT, option);
break;
case WANTNO:
switch(tn->himq[option])
{
case EMPTY:
/* Already negotiating for NO */
break;
case OPPOSITE:
tn->himq[option] = EMPTY;
break;
}
break;
case WANTYES:
switch(tn->himq[option])
{
case EMPTY:
tn->himq[option] = OPPOSITE;
break;
case OPPOSITE:
break;
}
break;
}
}
}
static
void rec_will(struct connectdata *conn, int option)
{
struct TELNET *tn = (struct TELNET *)conn->proto.telnet;
switch(tn->him[option])
{
case NO:
if(tn->him_preferred[option] == YES)
{
tn->him[option] = YES;
send_negotiation(conn, DO, option);
}
else
{
send_negotiation(conn, DONT, option);
}
break;
case YES:
/* Already enabled */
break;
case WANTNO:
switch(tn->himq[option])
{
case EMPTY:
/* Error: DONT answered by WILL */
tn->him[option] = NO;
break;
case OPPOSITE:
/* Error: DONT answered by WILL */
tn->him[option] = YES;
tn->himq[option] = EMPTY;
break;
}
break;
case WANTYES:
switch(tn->himq[option])
{
case EMPTY:
tn->him[option] = YES;
break;
case OPPOSITE:
tn->him[option] = WANTNO;
tn->himq[option] = EMPTY;
send_negotiation(conn, DONT, option);
break;
}
break;
}
}
static
void rec_wont(struct connectdata *conn, int option)
{
struct TELNET *tn = (struct TELNET *)conn->proto.telnet;
switch(tn->him[option])
{
case NO:
/* Already disabled */
break;
case YES:
tn->him[option] = NO;
send_negotiation(conn, DONT, option);
break;
case WANTNO:
switch(tn->himq[option])
{
case EMPTY:
tn->him[option] = NO;
break;
case OPPOSITE:
tn->him[option] = WANTYES;
tn->himq[option] = EMPTY;
send_negotiation(conn, DO, option);
break;
}
break;
case WANTYES:
switch(tn->himq[option])
{
case EMPTY:
tn->him[option] = NO;
break;
case OPPOSITE:
tn->him[option] = NO;
tn->himq[option] = EMPTY;
break;
}
break;
}
}
void set_local_option(struct connectdata *conn, int option, int newstate)
{
struct TELNET *tn = (struct TELNET *)conn->proto.telnet;
if(newstate == YES)
{
switch(tn->us[option])
{
case NO:
tn->us[option] = WANTYES;
send_negotiation(conn, WILL, option);
break;
case YES:
/* Already enabled */
break;
case WANTNO:
switch(tn->usq[option])
{
case EMPTY:
/* Already negotiating for YES, queue the request */
tn->usq[option] = OPPOSITE;
break;
case OPPOSITE:
/* Error: already queued an enable request */
break;
}
break;
case WANTYES:
switch(tn->usq[option])
{
case EMPTY:
/* Error: already negotiating for enable */
break;
case OPPOSITE:
tn->usq[option] = EMPTY;
break;
}
break;
}
}
else /* NO */
{
switch(tn->us[option])
{
case NO:
/* Already disabled */
break;
case YES:
tn->us[option] = WANTNO;
send_negotiation(conn, WONT, option);
break;
case WANTNO:
switch(tn->usq[option])
{
case EMPTY:
/* Already negotiating for NO */
break;
case OPPOSITE:
tn->usq[option] = EMPTY;
break;
}
break;
case WANTYES:
switch(tn->usq[option])
{
case EMPTY:
tn->usq[option] = OPPOSITE;
break;
case OPPOSITE:
break;
}
break;
}
}
}
static
void rec_do(struct connectdata *conn, int option)
{
struct TELNET *tn = (struct TELNET *)conn->proto.telnet;
switch(tn->us[option])
{
case NO:
if(tn->us_preferred[option] == YES)
{
tn->us[option] = YES;
send_negotiation(conn, WILL, option);
}
else
{
send_negotiation(conn, WONT, option);
}
break;
case YES:
/* Already enabled */
break;
case WANTNO:
switch(tn->usq[option])
{
case EMPTY:
/* Error: DONT answered by WILL */
tn->us[option] = NO;
break;
case OPPOSITE:
/* Error: DONT answered by WILL */
tn->us[option] = YES;
tn->usq[option] = EMPTY;
break;
}
break;
case WANTYES:
switch(tn->usq[option])
{
case EMPTY:
tn->us[option] = YES;
break;
case OPPOSITE:
tn->us[option] = WANTNO;
tn->himq[option] = EMPTY;
send_negotiation(conn, WONT, option);
break;
}
break;
}
}
static
void rec_dont(struct connectdata *conn, int option)
{
struct TELNET *tn = (struct TELNET *)conn->proto.telnet;
switch(tn->us[option])
{
case NO:
/* Already disabled */
break;
case YES:
tn->us[option] = NO;
send_negotiation(conn, WONT, option);
break;
case WANTNO:
switch(tn->usq[option])
{
case EMPTY:
tn->us[option] = NO;
break;
case OPPOSITE:
tn->us[option] = WANTYES;
tn->usq[option] = EMPTY;
send_negotiation(conn, WILL, option);
break;
}
break;
case WANTYES:
switch(tn->usq[option])
{
case EMPTY:
tn->us[option] = NO;
break;
case OPPOSITE:
tn->us[option] = NO;
tn->usq[option] = EMPTY;
break;
}
break;
}
}
static void printsub(struct UrlData *data,
int direction, /* '<' or '>' */
unsigned char *pointer, /* where suboption data is */
int length) /* length of suboption data */
{
int i = 0;
if (data->bits.verbose)
{
if (direction)
{
printf("%s IAC SB ", (direction == '<')? "RCVD":"SENT");
if (length >= 3)
{
int j;
i = pointer[length-2];
j = pointer[length-1];
if (i != IAC || j != SE)
{
printf("(terminated by ");
if (TELOPT_OK(i))
printf("%s ", TELOPT(i));
else if (TELCMD_OK(i))
printf("%s ", TELCMD(i));
else
printf("%d ", i);
if (TELOPT_OK(j))
printf("%s", TELOPT(j));
else if (TELCMD_OK(j))
printf("%s", TELCMD(j));
else
printf("%d", j);
printf(", not IAC SE!) ");
}
}
length -= 2;
}
if (length < 1)
{
printf("(Empty suboption?)");
return;
}
if (TELOPT_OK(pointer[0])) {
switch(pointer[0]) {
case TELOPT_TTYPE:
case TELOPT_XDISPLOC:
case TELOPT_NEW_ENVIRON:
printf("%s", TELOPT(pointer[0]));
break;
default:
printf("%s (unsupported)", TELOPT(pointer[0]));
break;
}
}
else
printf("%d (unknown)", pointer[i]);
switch(pointer[1]) {
case TELQUAL_IS:
printf(" IS");
break;
case TELQUAL_SEND:
printf(" SEND");
break;
case TELQUAL_INFO:
printf(" INFO/REPLY");
break;
case TELQUAL_NAME:
printf(" NAME");
break;
}
switch(pointer[0]) {
case TELOPT_TTYPE:
case TELOPT_XDISPLOC:
pointer[length] = 0;
printf(" \"%s\"", &pointer[2]);
break;
case TELOPT_NEW_ENVIRON:
if(pointer[1] == TELQUAL_IS) {
printf(" ");
for(i = 3;i < length;i++) {
switch(pointer[i]) {
case NEW_ENV_VAR:
printf(", ");
break;
case NEW_ENV_VALUE:
printf(" = ");
break;
default:
printf("%c", pointer[i]);
break;
}
}
}
break;
default:
for (i = 2; i < length; i++)
printf(" %.2x", pointer[i]);
break;
}
if (direction)
{
printf("\n");
}
}
}
static int check_telnet_options(struct connectdata *conn)
{
struct curl_slist *head;
char option_keyword[128];
char option_arg[256];
char *buf;
struct UrlData *data = conn->data;
struct TELNET *tn = (struct TELNET *)conn->proto.telnet;
/* Add the user name as an environment variable if it
was given on the command line */
if(data->bits.user_passwd)
{
char *buf = malloc(256);
sprintf(buf, "USER,%s", data->user);
tn->telnet_vars = curl_slist_append(tn->telnet_vars, buf);
tn->us_preferred[TELOPT_NEW_ENVIRON] = YES;
}
for(head = data->telnet_options; head; head=head->next) {
if(sscanf(head->data, "%127[^= ]%*[ =]%255s",
option_keyword, option_arg) == 2) {
/* Terminal type */
if(strequal(option_keyword, "TTYPE")) {
tn->subopt_ttype = option_arg;
tn->us_preferred[TELOPT_TTYPE] = YES;
continue;
}
/* Display variable */
if(strequal(option_keyword, "XDISPLOC")) {
tn->subopt_xdisploc = option_arg;
tn->us_preferred[TELOPT_XDISPLOC] = YES;
continue;
}
/* Environment variable */
if(strequal(option_keyword, "NEW_ENV")) {
buf = strdup(option_arg);
if(!buf)
return CURLE_OUT_OF_MEMORY;
tn->telnet_vars = curl_slist_append(tn->telnet_vars, buf);
tn->us_preferred[TELOPT_NEW_ENVIRON] = YES;
continue;
}
failf(data, "Unknown telnet option %s", head->data);
return CURLE_UNKNOWN_TELNET_OPTION;
} else {
failf(data, "Syntax error in telnet option: %s", head->data);
return CURLE_TELNET_OPTION_SYNTAX;
}
}
return CURLE_OK;
}
/*
* suboption()
*
* Look at the sub-option buffer, and try to be helpful to the other
* side.
*/
static void suboption(struct connectdata *conn)
{
struct curl_slist *v;
unsigned char subchar;
unsigned char temp[2048];
int len;
int tmplen;
char varname[128];
char varval[128];
struct UrlData *data = conn->data;
struct TELNET *tn = (struct TELNET *)conn->proto.telnet;
printsub(data, '<', (unsigned char *)tn->subbuffer, SB_LEN(tn)+2);
switch (subchar = SB_GET(tn)) {
case TELOPT_TTYPE:
len = strlen(tn->subopt_ttype) + 4 + 2;
snprintf((char *)temp, sizeof(temp),
"%c%c%c%c%s%c%c", IAC, SB, TELOPT_TTYPE,
TELQUAL_IS, tn->subopt_ttype, IAC, SE);
swrite(conn->firstsocket, temp, len);
printsub(data, '>', &temp[2], len-2);
break;
case TELOPT_XDISPLOC:
len = strlen(tn->subopt_xdisploc) + 4 + 2;
snprintf((char *)temp, sizeof(temp),
"%c%c%c%c%s%c%c", IAC, SB, TELOPT_XDISPLOC,
TELQUAL_IS, tn->subopt_xdisploc, IAC, SE);
swrite(conn->firstsocket, temp, len);
printsub(data, '>', &temp[2], len-2);
break;
case TELOPT_NEW_ENVIRON:
snprintf((char *)temp, sizeof(temp),
"%c%c%c%c", IAC, SB, TELOPT_NEW_ENVIRON, TELQUAL_IS);
len = 4;
for(v = tn->telnet_vars;v;v = v->next) {
tmplen = (strlen(v->data) + 1);
/* Add the variable only if it fits */
if(len + tmplen < sizeof(temp)-6) {
sscanf(v->data, "%127[^,],%s", varname, varval);
snprintf((char *)&temp[len], sizeof(temp) - len,
"%c%s%c%s", NEW_ENV_VAR, varname,
NEW_ENV_VALUE, varval);
len += tmplen;
}
}
snprintf((char *)&temp[len], sizeof(temp) - len,
"%c%c", IAC, SE);
len += 2;
swrite(conn->firstsocket, temp, len);
printsub(data, '>', &temp[2], len-2);
break;
}
return;
}
static
void telrcv(struct connectdata *conn,
unsigned char *inbuf, /* Data received from socket */
int count) /* Number of bytes received */
{
unsigned char c;
int index = 0;
struct UrlData *data = conn->data;
struct TELNET *tn = (struct TELNET *)conn->proto.telnet;
while(count--)
{
c = inbuf[index++];
switch (tn->telrcv_state)
{
case TS_CR:
tn->telrcv_state = TS_DATA;
if (c == '\0')
{
break; /* Ignore \0 after CR */
}
Curl_client_write(data, CLIENTWRITE_BODY, (char *)&c, 1);
continue;
case TS_DATA:
if (c == IAC)
{
tn->telrcv_state = TS_IAC;
break;
}
else if(c == '\r')
{
tn->telrcv_state = TS_CR;
}
Curl_client_write(data, CLIENTWRITE_BODY, (char *)&c, 1);
continue;
case TS_IAC:
process_iac:
switch (c)
{
case WILL:
tn->telrcv_state = TS_WILL;
continue;
case WONT:
tn->telrcv_state = TS_WONT;
continue;
case DO:
tn->telrcv_state = TS_DO;
continue;
case DONT:
tn->telrcv_state = TS_DONT;
continue;
case SB:
SB_CLEAR(tn);
tn->telrcv_state = TS_SB;
continue;
case IAC:
Curl_client_write(data, CLIENTWRITE_BODY, (char *)&c, 1);
break;
case DM:
case NOP:
case GA:
default:
printoption(data, "RCVD", IAC, c);
break;
}
tn->telrcv_state = TS_DATA;
continue;
case TS_WILL:
printoption(data, "RCVD", WILL, c);
tn->please_negotiate = 1;
rec_will(conn, c);
tn->telrcv_state = TS_DATA;
continue;
case TS_WONT:
printoption(data, "RCVD", WONT, c);
tn->please_negotiate = 1;
rec_wont(conn, c);
tn->telrcv_state = TS_DATA;
continue;
case TS_DO:
printoption(data, "RCVD", DO, c);
tn->please_negotiate = 1;
rec_do(conn, c);
tn->telrcv_state = TS_DATA;
continue;
case TS_DONT:
printoption(data, "RCVD", DONT, c);
tn->please_negotiate = 1;
rec_dont(conn, c);
tn->telrcv_state = TS_DATA;
continue;
case TS_SB:
if (c == IAC)
{
tn->telrcv_state = TS_SE;
}
else
{
SB_ACCUM(tn,c);
}
continue;
case TS_SE:
if (c != SE)
{
if (c != IAC)
{
/*
* This is an error. We only expect to get
* "IAC IAC" or "IAC SE". Several things may
* have happend. An IAC was not doubled, the
* IAC SE was left off, or another option got
* inserted into the suboption are all possibilities.
* If we assume that the IAC was not doubled,
* and really the IAC SE was left off, we could
* get into an infinate loop here. So, instead,
* we terminate the suboption, and process the
* partial suboption if we can.
*/
SB_ACCUM(tn, (unsigned char)IAC);
SB_ACCUM(tn, c);
tn->subpointer -= 2;
SB_TERM(tn);
printoption(data, "In SUBOPTION processing, RCVD", IAC, c);
suboption(conn); /* handle sub-option */
tn->telrcv_state = TS_IAC;
goto process_iac;
}
SB_ACCUM(tn,c);
tn->telrcv_state = TS_SB;
}
else
{
SB_ACCUM(tn, (unsigned char)IAC);
SB_ACCUM(tn, (unsigned char)SE);
tn->subpointer -= 2;
SB_TERM(tn);
suboption(conn); /* handle sub-option */
tn->telrcv_state = TS_DATA;
}
break;
}
}
}
CURLcode Curl_telnet_done(struct connectdata *conn)
{
struct TELNET *tn = (struct TELNET *)conn->proto.telnet;
curl_slist_free_all(tn->telnet_vars);
free(conn->proto.telnet);
conn->proto.telnet = NULL;
return CURLE_OK;
}
CURLcode Curl_telnet(struct connectdata *conn)
{
CURLcode code;
struct UrlData *data = conn->data;
int sockfd = conn->firstsocket;
fd_set readfd;
fd_set keepfd;
bool keepon = TRUE;
char *buf = data->buffer;
ssize_t nread;
struct TELNET *tn;
code = init_telnet(conn);
if(code)
return code;
tn = (struct TELNET *)conn->proto.telnet;
code = check_telnet_options(conn);
if(code)
return code;
FD_ZERO (&readfd); /* clear it */
FD_SET (sockfd, &readfd);
FD_SET (1, &readfd);
keepfd = readfd;
while (keepon) {
readfd = keepfd; /* set this every lap in the loop */
switch (select (sockfd + 1, &readfd, NULL, NULL, NULL)) {
case -1: /* error, stop reading */
keepon = FALSE;
continue;
case 0: /* timeout */
break;
default: /* read! */
if(FD_ISSET(1, &readfd)) { /* read from stdin */
unsigned char outbuf[2];
int out_count = 0;
size_t bytes_written;
char *buffer = buf;
nread = read(1, buf, 255);
while(nread--) {
outbuf[0] = *buffer++;
out_count = 1;
if(outbuf[0] == IAC)
outbuf[out_count++] = IAC;
Curl_write(conn, conn->firstsocket, outbuf,
out_count, &bytes_written);
}
}
if(FD_ISSET(sockfd, &readfd)) {
Curl_read(conn, sockfd, buf, BUFSIZE - 1, &nread);
/* if we receive 0 or less here, the server closed the connection and
we bail out from this! */
if (nread <= 0) {
keepon = FALSE;
break;
}
telrcv(conn, (unsigned char *)buf, nread);
/* Negotiate if the peer has started negotiating,
otherwise don't. We don't want to speak telnet with
non-telnet servers, like POP or SMTP. */
if(tn->please_negotiate && !tn->already_negotiated) {
negotiate(conn);
tn->already_negotiated = 1;
}
}
}
}
/* mark this as "no further transfer wanted" */
return Curl_Transfer(conn, -1, -1, FALSE, NULL, -1, NULL);
}