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gateway.c
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gateway.c
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/*********************************************************************
*
* File : $Source: /cvsroot/ijbswa/current/gateway.c,v $
*
* Purpose : Contains functions to connect to a server, possibly
* using a "forwarder" (i.e. HTTP proxy and/or a SOCKS4
* or SOCKS5 proxy).
*
* Copyright : Written by and Copyright (C) 2001-2020 the
* Privoxy team. https://www.privoxy.org/
*
* Based on the Internet Junkbuster originally written
* by and Copyright (C) 1997 Anonymous Coders and
* Junkbusters Corporation. http://www.junkbusters.com
*
* This program is free software; you can redistribute it
* and/or modify it under the terms of the GNU General
* Public License as published by the Free Software
* Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will
* be useful, but WITHOUT ANY WARRANTY; without even the
* implied warranty of MERCHANTABILITY or FITNESS FOR A
* PARTICULAR PURPOSE. See the GNU General Public
* License for more details.
*
* The GNU General Public License should be included with
* this file. If not, you can view it at
* http://www.gnu.org/copyleft/gpl.html
* or write to the Free Software Foundation, Inc., 59
* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*********************************************************************/
#include "config.h"
#include <stdio.h>
#include <sys/types.h>
#ifndef _WIN32
#include <netinet/in.h>
#endif
#include <errno.h>
#include <string.h>
#include "assert.h"
#ifdef _WIN32
#include <winsock2.h>
#endif /* def _WIN32 */
#ifdef __BEOS__
#include <netdb.h>
#endif /* def __BEOS__ */
#include "project.h"
#include "jcc.h"
#include "errlog.h"
#include "jbsockets.h"
#include "gateway.h"
#include "miscutil.h"
#include "list.h"
#include "parsers.h"
#ifdef FEATURE_CONNECTION_KEEP_ALIVE
#ifdef HAVE_POLL
#ifdef __GLIBC__
#include <sys/poll.h>
#else
#include <poll.h>
#endif /* def __GLIBC__ */
#endif /* HAVE_POLL */
#endif /* def FEATURE_CONNECTION_KEEP_ALIVE */
static jb_socket socks4_connect(const struct forward_spec *fwd,
const char *target_host,
int target_port,
struct client_state *csp);
static jb_socket socks5_connect(const struct forward_spec *fwd,
const char *target_host,
int target_port,
struct client_state *csp);
enum {
SOCKS4_REQUEST_GRANTED = 90,
SOCKS4_REQUEST_REJECT = 91,
SOCKS4_REQUEST_IDENT_FAILED = 92,
SOCKS4_REQUEST_IDENT_CONFLICT = 93
};
enum {
SOCKS5_REQUEST_GRANTED = 0,
SOCKS5_REQUEST_FAILED = 1,
SOCKS5_REQUEST_DENIED = 2,
SOCKS5_REQUEST_NETWORK_UNREACHABLE = 3,
SOCKS5_REQUEST_HOST_UNREACHABLE = 4,
SOCKS5_REQUEST_CONNECTION_REFUSED = 5,
SOCKS5_REQUEST_TTL_EXPIRED = 6,
SOCKS5_REQUEST_PROTOCOL_ERROR = 7,
SOCKS5_REQUEST_BAD_ADDRESS_TYPE = 8
};
/* structure of a socks client operation */
struct socks_op {
unsigned char vn; /* socks version number */
unsigned char cd; /* command code */
unsigned char dstport[2]; /* destination port */
unsigned char dstip[4]; /* destination address */
char userid; /* first byte of userid */
char padding[3]; /* make sure sizeof(struct socks_op) is endian-independent. */
/* more bytes of the userid follow, terminated by a NULL */
};
/* structure of a socks server reply */
struct socks_reply {
unsigned char vn; /* socks version number */
unsigned char cd; /* command code */
unsigned char dstport[2]; /* destination port */
unsigned char dstip[4]; /* destination address */
};
static const char socks_userid[] = "anonymous";
#ifdef FEATURE_CONNECTION_SHARING
#ifndef FEATURE_CONNECTION_KEEP_ALIVE
#error Using FEATURE_CONNECTION_SHARING without FEATURE_CONNECTION_KEEP_ALIVE is impossible
#endif
#define MAX_REUSABLE_CONNECTIONS 100
static struct reusable_connection reusable_connection[MAX_REUSABLE_CONNECTIONS];
static int mark_connection_unused(const struct reusable_connection *connection);
/*********************************************************************
*
* Function : initialize_reusable_connections
*
* Description : Initializes the reusable_connection structures.
* Must be called with connection_reuse_mutex locked.
*
* Parameters : N/A
*
* Returns : void
*
*********************************************************************/
extern void initialize_reusable_connections(void)
{
unsigned int slot = 0;
#if !defined(HAVE_POLL) && !defined(_WIN32)
log_error(LOG_LEVEL_INFO,
"Detecting already dead connections might not work "
"correctly on your platform. In case of problems, "
"unset the keep-alive-timeout option.");
#endif
for (slot = 0; slot < SZ(reusable_connection); slot++)
{
mark_connection_closed(&reusable_connection[slot]);
}
log_error(LOG_LEVEL_CONNECT, "Initialized %d socket slots.", slot);
}
/*********************************************************************
*
* Function : remember_connection
*
* Description : Remembers a server connection for reuse later on.
*
* Parameters :
* 1 : connection = The server connection to remember.
*
* Returns : void
*
*********************************************************************/
void remember_connection(const struct reusable_connection *connection)
{
unsigned int slot = 0;
int free_slot_found = FALSE;
assert(NULL != connection);
assert(connection->sfd != JB_INVALID_SOCKET);
if (mark_connection_unused(connection))
{
return;
}
privoxy_mutex_lock(&connection_reuse_mutex);
/* Find free socket slot. */
for (slot = 0; slot < SZ(reusable_connection); slot++)
{
if (reusable_connection[slot].sfd == JB_INVALID_SOCKET)
{
assert(reusable_connection[slot].in_use == 0);
log_error(LOG_LEVEL_CONNECT,
"Remembering socket %d for %s:%d in slot %d.",
connection->sfd, connection->host, connection->port, slot);
free_slot_found = TRUE;
break;
}
}
if (!free_slot_found)
{
log_error(LOG_LEVEL_CONNECT,
"No free slots found to remember socket for %s:%d. Last slot %d.",
connection->host, connection->port, slot);
privoxy_mutex_unlock(&connection_reuse_mutex);
close_socket(connection->sfd);
return;
}
assert(slot < SZ(reusable_connection));
assert(NULL != connection->host);
reusable_connection[slot].host = strdup_or_die(connection->host);
reusable_connection[slot].sfd = connection->sfd;
reusable_connection[slot].port = connection->port;
reusable_connection[slot].in_use = 0;
reusable_connection[slot].timestamp = connection->timestamp;
reusable_connection[slot].request_sent = connection->request_sent;
reusable_connection[slot].response_received = connection->response_received;
reusable_connection[slot].keep_alive_timeout = connection->keep_alive_timeout;
reusable_connection[slot].requests_sent_total = connection->requests_sent_total;
assert(reusable_connection[slot].gateway_host == NULL);
assert(reusable_connection[slot].gateway_port == 0);
assert(reusable_connection[slot].auth_username == NULL);
assert(reusable_connection[slot].auth_password == NULL);
assert(reusable_connection[slot].forwarder_type == SOCKS_NONE);
assert(reusable_connection[slot].forward_host == NULL);
assert(reusable_connection[slot].forward_port == 0);
reusable_connection[slot].forwarder_type = connection->forwarder_type;
if (NULL != connection->gateway_host)
{
reusable_connection[slot].gateway_host = strdup_or_die(connection->gateway_host);
}
else
{
reusable_connection[slot].gateway_host = NULL;
}
reusable_connection[slot].gateway_port = connection->gateway_port;
if (NULL != connection->auth_username)
{
reusable_connection[slot].auth_username = strdup_or_die(connection->auth_username);
}
else
{
reusable_connection[slot].auth_username = NULL;
}
if (NULL != connection->auth_password)
{
reusable_connection[slot].auth_password = strdup_or_die(connection->auth_password);
}
else
{
reusable_connection[slot].auth_password = NULL;
}
if (NULL != connection->forward_host)
{
reusable_connection[slot].forward_host = strdup_or_die(connection->forward_host);
}
else
{
reusable_connection[slot].forward_host = NULL;
}
reusable_connection[slot].forward_port = connection->forward_port;
privoxy_mutex_unlock(&connection_reuse_mutex);
}
#endif /* def FEATURE_CONNECTION_SHARING */
/*********************************************************************
*
* Function : mark_connection_closed
*
* Description : Marks a reused connection closed.
*
* Parameters :
* 1 : closed_connection = The connection to mark as closed.
*
* Returns : void
*
*********************************************************************/
void mark_connection_closed(struct reusable_connection *closed_connection)
{
closed_connection->in_use = FALSE;
closed_connection->sfd = JB_INVALID_SOCKET;
freez(closed_connection->host);
closed_connection->port = 0;
closed_connection->timestamp = 0;
closed_connection->request_sent = 0;
closed_connection->response_received = 0;
closed_connection->keep_alive_timeout = 0;
closed_connection->requests_sent_total = 0;
closed_connection->forwarder_type = SOCKS_NONE;
freez(closed_connection->gateway_host);
closed_connection->gateway_port = 0;
freez(closed_connection->auth_username);
freez(closed_connection->auth_password);
freez(closed_connection->forward_host);
closed_connection->forward_port = 0;
}
#ifdef FEATURE_CONNECTION_SHARING
/*********************************************************************
*
* Function : forget_connection
*
* Description : Removes a previously remembered connection from
* the list of reusable connections.
*
* Parameters :
* 1 : sfd = The socket belonging to the connection in question.
*
* Returns : void
*
*********************************************************************/
void forget_connection(jb_socket sfd)
{
unsigned int slot = 0;
assert(sfd != JB_INVALID_SOCKET);
privoxy_mutex_lock(&connection_reuse_mutex);
for (slot = 0; slot < SZ(reusable_connection); slot++)
{
if (reusable_connection[slot].sfd == sfd)
{
assert(reusable_connection[slot].in_use);
log_error(LOG_LEVEL_CONNECT,
"Forgetting socket %d for %s:%d in slot %d.",
sfd, reusable_connection[slot].host,
reusable_connection[slot].port, slot);
mark_connection_closed(&reusable_connection[slot]);
break;
}
}
privoxy_mutex_unlock(&connection_reuse_mutex);
}
#endif /* def FEATURE_CONNECTION_SHARING */
#ifdef FEATURE_CONNECTION_KEEP_ALIVE
/*********************************************************************
*
* Function : string_or_none
*
* Description : Returns a given string or "none" if a NULL pointer
* is given.
* Helper function for connection_destination_matches().
*
* Parameters :
* 1 : string = The string to check.
*
* Returns : The string if non-NULL, "none" otherwise.
*
*********************************************************************/
static const char *string_or_none(const char *string)
{
return(string != NULL ? string : "none");
}
/*********************************************************************
*
* Function : connection_detail_matches
*
* Description : Helper function for connection_destination_matches().
* Compares strings which can be NULL.
*
* Parameters :
* 1 : connection_detail = The connection detail to compare.
* 2 : fowarder_detail = The forwarder detail to compare.
*
* Returns : TRUE for yes, FALSE otherwise.
*
*********************************************************************/
static int connection_detail_matches(const char *connection_detail,
const char *forwarder_detail)
{
if (connection_detail == NULL && forwarder_detail == NULL)
{
/* Both details are unset. */
return TRUE;
}
if ((connection_detail == NULL && forwarder_detail != NULL)
|| (connection_detail != NULL && forwarder_detail == NULL))
{
/* Only one detail isn't set. */
return FALSE;
}
/* Both details are set, but do they match? */
return(!strcmpic(connection_detail, forwarder_detail));
}
/*********************************************************************
*
* Function : connection_destination_matches
*
* Description : Determines whether a remembered connection can
* be reused. That is, whether the destination and
* the forwarding settings match.
*
* Parameters :
* 1 : connection = The connection to check.
* 2 : http = The destination for the connection.
* 3 : fwd = The forwarder settings.
*
* Returns : TRUE for yes, FALSE otherwise.
*
*********************************************************************/
int connection_destination_matches(const struct reusable_connection *connection,
const struct http_request *http,
const struct forward_spec *fwd)
{
if ((connection->forwarder_type != fwd->type)
|| (connection->gateway_port != fwd->gateway_port)
|| (connection->forward_port != fwd->forward_port)
|| (connection->port != http->port))
{
return FALSE;
}
if (!connection_detail_matches(connection->gateway_host, fwd->gateway_host))
{
log_error(LOG_LEVEL_CONNECT,
"Gateway mismatch. Previous gateway: %s. Current gateway: %s",
string_or_none(connection->gateway_host),
string_or_none(fwd->gateway_host));
return FALSE;
}
if (!connection_detail_matches(connection->auth_username, fwd->auth_username))
{
log_error(LOG_LEVEL_CONNECT, "Socks user name mismatch. "
"Previous user name: %s. Current user name: %s",
string_or_none(connection->auth_username),
string_or_none(fwd->auth_username));
return FALSE;
}
if (!connection_detail_matches(connection->auth_password, fwd->auth_password))
{
log_error(LOG_LEVEL_CONNECT, "Socks user name mismatch. "
"Previous password: %s. Current password: %s",
string_or_none(connection->auth_password),
string_or_none(fwd->auth_password));
return FALSE;
}
if (!connection_detail_matches(connection->forward_host, fwd->forward_host))
{
log_error(LOG_LEVEL_CONNECT,
"Forwarding proxy mismatch. Previous proxy: %s. Current proxy: %s",
string_or_none(connection->forward_host),
string_or_none(fwd->forward_host));
return FALSE;
}
return (!strcmpic(connection->host, http->host));
}
#endif /* def FEATURE_CONNECTION_KEEP_ALIVE */
#ifdef FEATURE_CONNECTION_SHARING
/*********************************************************************
*
* Function : close_unusable_connections
*
* Description : Closes remembered connections that have timed
* out or have been closed on the other side.
*
* Parameters : none
*
* Returns : Number of connections that are still alive.
*
*********************************************************************/
int close_unusable_connections(void)
{
unsigned int slot = 0;
int connections_alive = 0;
privoxy_mutex_lock(&connection_reuse_mutex);
for (slot = 0; slot < SZ(reusable_connection); slot++)
{
if (!reusable_connection[slot].in_use
&& (JB_INVALID_SOCKET != reusable_connection[slot].sfd))
{
time_t time_open = time(NULL) - reusable_connection[slot].timestamp;
time_t latency = (reusable_connection[slot].response_received -
reusable_connection[slot].request_sent) / 2;
if (reusable_connection[slot].keep_alive_timeout < time_open + latency)
{
log_error(LOG_LEVEL_CONNECT,
"The connection to %s:%d in slot %d timed out. "
"Closing socket %d. Timeout is: %d. Assumed latency: %ld.",
reusable_connection[slot].host,
reusable_connection[slot].port, slot,
reusable_connection[slot].sfd,
reusable_connection[slot].keep_alive_timeout,
latency);
close_socket(reusable_connection[slot].sfd);
mark_connection_closed(&reusable_connection[slot]);
}
else if (!socket_is_still_alive(reusable_connection[slot].sfd))
{
log_error(LOG_LEVEL_CONNECT,
"The connection to %s:%d in slot %d is no longer usable. "
"Closing socket %d.", reusable_connection[slot].host,
reusable_connection[slot].port, slot,
reusable_connection[slot].sfd);
close_socket(reusable_connection[slot].sfd);
mark_connection_closed(&reusable_connection[slot]);
}
else
{
connections_alive++;
}
}
}
privoxy_mutex_unlock(&connection_reuse_mutex);
return connections_alive;
}
/*********************************************************************
*
* Function : get_reusable_connection
*
* Description : Returns an open socket to a previously remembered
* open connection (if there is one).
*
* Parameters :
* 1 : http = The destination for the connection.
* 2 : fwd = The forwarder settings.
*
* Returns : JB_INVALID_SOCKET => No reusable connection found,
* otherwise a usable socket.
*
*********************************************************************/
static jb_socket get_reusable_connection(const struct http_request *http,
const struct forward_spec *fwd)
{
jb_socket sfd = JB_INVALID_SOCKET;
unsigned int slot = 0;
close_unusable_connections();
privoxy_mutex_lock(&connection_reuse_mutex);
for (slot = 0; slot < SZ(reusable_connection); slot++)
{
if (!reusable_connection[slot].in_use
&& (JB_INVALID_SOCKET != reusable_connection[slot].sfd))
{
if (connection_destination_matches(&reusable_connection[slot], http, fwd))
{
reusable_connection[slot].in_use = TRUE;
sfd = reusable_connection[slot].sfd;
log_error(LOG_LEVEL_CONNECT,
"Found reusable socket %d for %s:%d in slot %d. Timestamp made %ld "
"seconds ago. Timeout: %d. Latency: %d. Requests served: %d",
sfd, reusable_connection[slot].host, reusable_connection[slot].port,
slot, time(NULL) - reusable_connection[slot].timestamp,
reusable_connection[slot].keep_alive_timeout,
(int)(reusable_connection[slot].response_received -
reusable_connection[slot].request_sent),
reusable_connection[slot].requests_sent_total);
break;
}
}
}
privoxy_mutex_unlock(&connection_reuse_mutex);
return sfd;
}
/*********************************************************************
*
* Function : mark_connection_unused
*
* Description : Gives a remembered connection free for reuse.
*
* Parameters :
* 1 : connection = The connection in question.
*
* Returns : TRUE => Socket found and marked as unused.
* FALSE => Socket not found.
*
*********************************************************************/
static int mark_connection_unused(const struct reusable_connection *connection)
{
unsigned int slot = 0;
int socket_found = FALSE;
assert(connection->sfd != JB_INVALID_SOCKET);
privoxy_mutex_lock(&connection_reuse_mutex);
for (slot = 0; slot < SZ(reusable_connection); slot++)
{
if (reusable_connection[slot].sfd == connection->sfd)
{
assert(reusable_connection[slot].in_use);
socket_found = TRUE;
log_error(LOG_LEVEL_CONNECT,
"Marking open socket %d for %s:%d in slot %d as unused.",
connection->sfd, reusable_connection[slot].host,
reusable_connection[slot].port, slot);
reusable_connection[slot].in_use = 0;
reusable_connection[slot].timestamp = connection->timestamp;
break;
}
}
privoxy_mutex_unlock(&connection_reuse_mutex);
return socket_found;
}
#endif /* def FEATURE_CONNECTION_SHARING */
/*********************************************************************
*
* Function : forwarded_connect
*
* Description : Connect to a specified web server, possibly via
* a HTTP proxy and/or a SOCKS proxy.
*
* Parameters :
* 1 : fwd = the proxies to use when connecting.
* 2 : http = the http request and apropos headers
* 3 : csp = Current client state (buffers, headers, etc...)
*
* Returns : JB_INVALID_SOCKET => failure, else it is the socket file descriptor.
*
*********************************************************************/
jb_socket forwarded_connect(const struct forward_spec *fwd,
struct http_request *http,
struct client_state *csp)
{
const char *dest_host;
int dest_port;
jb_socket sfd = JB_INVALID_SOCKET;
#ifdef FEATURE_CONNECTION_SHARING
if ((csp->config->feature_flags & RUNTIME_FEATURE_CONNECTION_SHARING)
&& !(csp->flags & CSP_FLAG_SERVER_SOCKET_TAINTED))
{
sfd = get_reusable_connection(http, fwd);
if (JB_INVALID_SOCKET != sfd)
{
return sfd;
}
}
#endif /* def FEATURE_CONNECTION_SHARING */
/* Figure out if we need to connect to the web server or a HTTP proxy. */
if (fwd->forward_host)
{
/* HTTP proxy */
dest_host = fwd->forward_host;
dest_port = fwd->forward_port;
}
else
{
/* Web server */
dest_host = http->host;
dest_port = http->port;
}
/* Connect, maybe using a SOCKS proxy */
switch (fwd->type)
{
case SOCKS_NONE:
case FORWARD_WEBSERVER:
sfd = connect_to(dest_host, dest_port, csp);
break;
case SOCKS_4:
case SOCKS_4A:
sfd = socks4_connect(fwd, dest_host, dest_port, csp);
break;
case SOCKS_5:
case SOCKS_5T:
sfd = socks5_connect(fwd, dest_host, dest_port, csp);
break;
default:
/* Should never get here */
log_error(LOG_LEVEL_FATAL,
"Internal error in forwarded_connect(). Bad proxy type: %d", fwd->type);
}
if (JB_INVALID_SOCKET != sfd)
{
log_error(LOG_LEVEL_CONNECT,
"Created new connection to %s:%d on socket %d.",
http->host, http->port, sfd);
}
return sfd;
}
#ifdef FUZZ
/*********************************************************************
*
* Function : socks_fuzz
*
* Description : Wrapper around socks[45]_connect() used for fuzzing.
*
* Parameters :
* 1 : csp = Current client state (buffers, headers, etc...)
*
* Returns : JB_ERR_OK or JB_ERR_PARSE
*
*********************************************************************/
extern jb_err socks_fuzz(struct client_state *csp)
{
jb_socket socket;
static struct forward_spec fwd;
char target_host[] = "fuzz.example.org";
int target_port = 12345;
fwd.gateway_host = strdup_or_die("fuzz.example.org");
fwd.gateway_port = 12345;
fwd.type = SOCKS_4A;
socket = socks4_connect(&fwd, target_host, target_port, csp);
if (JB_INVALID_SOCKET != socket)
{
fwd.type = SOCKS_5;
socket = socks5_connect(&fwd, target_host, target_port, csp);
}
if (JB_INVALID_SOCKET == socket)
{
log_error(LOG_LEVEL_ERROR, "%s", csp->error_message);
return JB_ERR_PARSE;
}
log_error(LOG_LEVEL_INFO, "Input looks like an acceptable socks response");
return JB_ERR_OK;
}
#endif
/*********************************************************************
*
* Function : socks4_connect
*
* Description : Connect to the SOCKS server, and connect through
* it to the specified server. This handles
* all the SOCKS negotiation, and returns a file
* descriptor for a socket which can be treated as a
* normal (non-SOCKS) socket.
*
* Logged error messages are saved to csp->error_message
* and later reused by error_response() for the CGI
* message. strdup allocation failures are handled there.
*
* Parameters :
* 1 : fwd = Specifies the SOCKS proxy to use.
* 2 : target_host = The final server to connect to.
* 3 : target_port = The final port to connect to.
* 4 : csp = Current client state (buffers, headers, etc...)
*
* Returns : JB_INVALID_SOCKET => failure, else a socket file descriptor.
*
*********************************************************************/
static jb_socket socks4_connect(const struct forward_spec *fwd,
const char *target_host,
int target_port,
struct client_state *csp)
{
unsigned long web_server_addr;
char buf[BUFFER_SIZE];
struct socks_op *c = (struct socks_op *)buf;
struct socks_reply *s = (struct socks_reply *)buf;
size_t n;
size_t csiz;
jb_socket sfd;
int err = 0;
char *errstr = NULL;
if ((fwd->gateway_host == NULL) || (*fwd->gateway_host == '\0'))
{
/* XXX: Shouldn't the config file parser prevent this? */
errstr = "NULL gateway host specified.";
err = 1;
}
if (fwd->gateway_port <= 0)
{
errstr = "invalid gateway port specified.";
err = 1;
}
if (err)
{
log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
csp->error_message = strdup(errstr);
errno = EINVAL;
return(JB_INVALID_SOCKET);
}
/* build a socks request for connection to the web server */
strlcpy(&(c->userid), socks_userid, sizeof(buf) - sizeof(struct socks_op));
csiz = sizeof(*c) + sizeof(socks_userid) - sizeof(c->userid) - sizeof(c->padding);
switch (fwd->type)
{
case SOCKS_4:
web_server_addr = resolve_hostname_to_ip(target_host);
if (web_server_addr == INADDR_NONE)
{
errstr = "could not resolve target host";
log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s %s", errstr, target_host);
err = 1;
}
else
{
web_server_addr = htonl(web_server_addr);
}
break;
case SOCKS_4A:
web_server_addr = 0x00000001;
n = csiz + strlen(target_host) + 1;
if (n > sizeof(buf))
{
errno = EINVAL;
errstr = "buffer cbuf too small.";
log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
err = 1;
}
else
{
strlcpy(buf + csiz, target_host, sizeof(buf) - sizeof(struct socks_op) - csiz);
/*
* What we forward to the socks4a server should have the
* size of socks_op, plus the length of the userid plus
* its \0 byte (which we don't have to add because the
* first byte of the userid is counted twice as it's also
* part of sock_op) minus the padding bytes (which are part
* of the userid as well), plus the length of the target_host
* (which is stored csiz bytes after the beginning of the buffer),
* plus another \0 byte.
*/
assert(n == sizeof(struct socks_op) + strlen(&(c->userid)) - sizeof(c->padding) + strlen(buf + csiz) + 1);
csiz = n;
}
break;
default:
/* Should never get here */
log_error(LOG_LEVEL_FATAL,
"socks4_connect: SOCKS4 impossible internal error - bad SOCKS type.");
/* Not reached */
return(JB_INVALID_SOCKET);
}
if (err)
{
csp->error_message = strdup(errstr);
return(JB_INVALID_SOCKET);
}
c->vn = 4;
c->cd = 1;
c->dstport[0] = (unsigned char)((target_port >> 8 ) & 0xff);
c->dstport[1] = (unsigned char)((target_port ) & 0xff);
c->dstip[0] = (unsigned char)((web_server_addr >> 24) & 0xff);
c->dstip[1] = (unsigned char)((web_server_addr >> 16) & 0xff);
c->dstip[2] = (unsigned char)((web_server_addr >> 8) & 0xff);
c->dstip[3] = (unsigned char)((web_server_addr ) & 0xff);
#ifdef FUZZ
sfd = 0;
#else
/* pass the request to the socks server */
sfd = connect_to(fwd->gateway_host, fwd->gateway_port, csp);
if (sfd == JB_INVALID_SOCKET)
{
/* The error an its reason have already been logged by connect_to() */
return(JB_INVALID_SOCKET);
}
else if (write_socket(sfd, (char *)c, csiz))
{
errstr = "SOCKS4 negotiation write failed.";
log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
err = 1;
close_socket(sfd);
}
else if (!data_is_available(sfd, csp->config->socket_timeout))
{
if (socket_is_still_alive(sfd))
{
errstr = "SOCKS4 negotiation timed out";
}
else
{
errstr = "SOCKS4 negotiation got aborted by the server";
}
log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
err = 1;
close_socket(sfd);
}
else
#endif
if (read_socket(sfd, buf, sizeof(buf)) != sizeof(*s))
{
errstr = "SOCKS4 negotiation read failed.";
log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
err = 1;
close_socket(sfd);
}
if (err)
{
csp->error_message = strdup(errstr);
return(JB_INVALID_SOCKET);
}
switch (s->cd)
{
case SOCKS4_REQUEST_GRANTED:
return(sfd);
case SOCKS4_REQUEST_REJECT:
errstr = "SOCKS request rejected or failed.";
errno = EINVAL;
break;
case SOCKS4_REQUEST_IDENT_FAILED:
errstr = "SOCKS request rejected because "
"SOCKS server cannot connect to identd on the client.";
errno = EACCES;
break;
case SOCKS4_REQUEST_IDENT_CONFLICT:
errstr = "SOCKS request rejected because "
"the client program and identd report "
"different user-ids.";
errno = EACCES;
break;
default:
errno = ENOENT;
snprintf(buf, sizeof(buf),
"SOCKS request rejected for reason code %d.", s->cd);
errstr = buf;
}
log_error(LOG_LEVEL_CONNECT, "socks4_connect: %s", errstr);
csp->error_message = strdup(errstr);
close_socket(sfd);
return(JB_INVALID_SOCKET);
}
/*********************************************************************
*
* Function : translate_socks5_error
*
* Description : Translates a SOCKS errors to a string.
*
* Parameters :
* 1 : socks_error = The error code to translate.
*
* Returns : The string translation.