const char gateway_rcs[] = "$Id: gateway.c,v 1.38 2008/10/24 17:33:00 fabiankeil Exp $"; /********************************************************************* * * 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 * proxy). * * Copyright : Written by and Copyright (C) 2001-2008 the SourceForge * Privoxy team. http://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. * * Revisions : * $Log: gateway.c,v $ * Revision 1.38 2008/10/24 17:33:00 fabiankeil * - Tone the "keep-alive support is experimental" warning * down a bit as hackish 0-chunk detection has been * implemented recently. * - Only show the "ndef HAVE_POLL" warning once on start-up. * * Revision 1.37 2008/10/23 17:40:53 fabiankeil * Fix forget_connection() and mark_connection_unused(), * which would both under certain circumstances access * reusable_connection[MAX_REUSABLE_CONNECTIONS]. Oops. * * Revision 1.36 2008/10/18 19:49:15 fabiankeil * - Factor close_unusable_connections() out of * get_reusable_connection() to make sure we really check * all the remembered connections, not just the ones before * the next reusable one. * - Plug two file descriptor leaks. Internally marking * connections as closed doesn't cut it. * * Revision 1.35 2008/10/17 17:12:01 fabiankeil * In socket_is_still_usable(), use select() * and FD_ISSET() if poll() isn't available. * * Revision 1.34 2008/10/17 17:07:13 fabiankeil * Add preliminary timeout support. * * Revision 1.33 2008/10/16 16:34:21 fabiankeil * Fix two gcc44 warnings. * * Revision 1.32 2008/10/16 16:27:22 fabiankeil * Fix compiler warning. * * Revision 1.31 2008/10/16 07:31:11 fabiankeil * - Factor socket_is_still_usable() out of get_reusable_connection(). * - If poll() isn't available, show a warning and assume the socket * is still usable. * * Revision 1.30 2008/10/13 17:31:03 fabiankeil * If a remembered connection is no longer usable and * has been marked closed, don't bother checking if the * destination matches. * * Revision 1.29 2008/10/11 16:59:41 fabiankeil * Add missing dots for two log messages. * * Revision 1.28 2008/10/09 18:21:41 fabiankeil * Flush work-in-progress changes to keep outgoing connections * alive where possible. Incomplete and mostly #ifdef'd out. * * Revision 1.27 2008/09/27 15:05:51 fabiankeil * Return only once in forwarded_connect(). * * Revision 1.26 2008/08/18 17:42:06 fabiankeil * Fix typo in macro name. * * Revision 1.25 2008/02/07 18:09:46 fabiankeil * In socks5_connect: * - make the buffers quite a bit smaller. * - properly report "socks5 server unreachable" failures. * - let strncpy() use the whole buffer. Using a length of 0xffu wasn't actually * wrong, but requires too much thinking as it doesn't depend on the buffer size. * - log a message if the socks5 server sends more data than expected. * - add some assertions and comments. * * Revision 1.24 2008/02/04 14:56:29 fabiankeil * - Fix a compiler warning. * - Stop assuming that htonl(INADDR_NONE) equals INADDR_NONE. * * Revision 1.23 2008/02/04 13:11:35 fabiankeil * Remember the cause of the SOCKS5 error for the CGI message. * * Revision 1.22 2008/02/03 13:46:15 fabiankeil * Add SOCKS5 support. Patch #1862863 by Eric M. Hopper with minor changes. * * Revision 1.21 2007/07/28 12:30:03 fabiankeil * Modified patch from Song Weijia (#1762559) to * fix socks requests on big-endian platforms. * * Revision 1.20 2007/05/14 10:23:48 fabiankeil * - Use strlcpy() instead of strcpy(). * - Use the same buffer for socks requests and socks responses. * - Fix bogus warning about web_server_addr being used uninitialized. * * Revision 1.19 2007/01/25 14:09:45 fabiankeil * - Save errors in socks4_connect() to csp->error_message. * - Silence some gcc43 warnings, hopefully the right way. * * Revision 1.18 2006/07/18 14:48:46 david__schmidt * Reorganizing the repository: swapping out what was HEAD (the old 3.1 branch) * with what was really the latest development (the v_3_0_branch branch) * * Revision 1.16 2002/05/12 21:36:29 jongfoster * Correcting function comments * * Revision 1.15 2002/03/26 22:29:54 swa * we have a new homepage! * * Revision 1.14 2002/03/24 13:25:43 swa * name change related issues * * Revision 1.13 2002/03/13 00:29:59 jongfoster * Killing warnings * * Revision 1.12 2002/03/09 20:03:52 jongfoster * - Making various functions return int rather than size_t. * (Undoing a recent change). Since size_t is unsigned on * Windows, functions like read_socket that return -1 on * error cannot return a size_t. * * THIS WAS A MAJOR BUG - it caused frequent, unpredictable * crashes, and also frequently caused JB to jump to 100% * CPU and stay there. (Because it thought it had just * read ((unsigned)-1) == 4Gb of data...) * * - The signature of write_socket has changed, it now simply * returns success=0/failure=nonzero. * * - Trying to get rid of a few warnings --with-debug on * Windows, I've introduced a new type "jb_socket". This is * used for the socket file descriptors. On Windows, this * is SOCKET (a typedef for unsigned). Everywhere else, it's * an int. The error value can't be -1 any more, so it's * now JB_INVALID_SOCKET (which is -1 on UNIX, and in * Windows it maps to the #define INVALID_SOCKET.) * * - The signature of bind_port has changed. * * Revision 1.11 2002/03/08 17:46:04 jongfoster * Fixing int/size_t warnings * * Revision 1.10 2002/03/07 03:50:19 oes * - Improved handling of failed DNS lookups * - Fixed compiler warnings * * Revision 1.9 2001/10/25 03:40:48 david__schmidt * Change in porting tactics: OS/2's EMX porting layer doesn't allow multiple * threads to call select() simultaneously. So, it's time to do a real, live, * native OS/2 port. See defines for __EMX__ (the porting layer) vs. __OS2__ * (native). Both versions will work, but using __OS2__ offers multi-threading. * * Revision 1.8 2001/09/13 20:10:12 jongfoster * Fixing missing #include under Windows * * Revision 1.7 2001/09/12 17:58:26 steudten * * add #include * * Revision 1.6 2001/09/10 10:41:16 oes * Added #include in.h * * Revision 1.5 2001/07/29 18:47:57 jongfoster * Adding missing #include project.h * * Revision 1.4 2001/07/24 12:47:06 oes * Applied BeOS support update by Eugenia * * Revision 1.3 2001/06/09 10:55:28 jongfoster * Changing BUFSIZ ==> BUFFER_SIZE * * Revision 1.2 2001/06/07 23:11:38 jongfoster * Removing gateways[] list - no longer used. * Replacing function pointer in struct gateway with a directly * called function forwarded_connect(), which can do the common * task of deciding whether to connect to the web server or HTTP * proxy. * Replacing struct gateway with struct forward_spec * Fixing bug with SOCKS4A and HTTP proxy server in combination. * It was a bug which led to the connection being made to the web * server rather than the HTTP proxy, and also a buffer overrun. * * Revision 1.1.1.1 2001/05/15 13:58:54 oes * Initial import of version 2.9.3 source tree * * *********************************************************************/ #include "config.h" #include #include #ifndef _WIN32 #include #endif #include #include #include "assert.h" #ifdef _WIN32 #include #endif /* def _WIN32 */ #ifdef __BEOS__ #include #endif /* def __BEOS__ */ #ifdef __OS2__ #include #endif /* def __OS2__ */ #include "project.h" #include "jcc.h" #include "errlog.h" #include "jbsockets.h" #include "gateway.h" #include "miscutil.h" #ifdef FEATURE_CONNECTION_KEEP_ALIVE #ifdef HAVE_POLL #ifdef __GLIBC__ #include #else #include #endif /* def __GLIBC__ */ #endif /* HAVE_POLL */ #endif /* def FEATURE_CONNECTION_KEEP_ALIVE */ const char gateway_h_rcs[] = GATEWAY_H_VERSION; 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); #define SOCKS_REQUEST_GRANTED 90 #define SOCKS_REQUEST_REJECT 91 #define SOCKS_REQUEST_IDENT_FAILED 92 #define SOCKS_REQUEST_IDENT_CONFLICT 93 #define SOCKS5_REQUEST_GRANTED 0 #define SOCKS5_REQUEST_FAILED 1 #define SOCKS5_REQUEST_DENIED 2 #define SOCKS5_REQUEST_NETWORK_UNREACHABLE 3 #define SOCKS5_REQUEST_HOST_UNREACHABLE 4 #define SOCKS5_REQUEST_CONNECTION_REFUSED 5 #define SOCKS5_REQUEST_TTL_EXPIRED 6 #define SOCKS5_REQUEST_PROTOCOL_ERROR 7 #define 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_KEEP_ALIVE #define MAX_REUSABLE_CONNECTIONS 100 /* XXX: should be a config option. */ #define CONNECTION_KEEP_ALIVE_TIMEOUT 3 * 60 struct reusable_connection { jb_socket sfd; int in_use; char *host; int port; time_t timestamp; int forwarder_type; char *gateway_host; int gateway_port; char *forward_host; int forward_port; }; static struct reusable_connection reusable_connection[MAX_REUSABLE_CONNECTIONS]; static int mark_connection_unused(jb_socket sfd); static void mark_connection_closed(struct reusable_connection *closed_connection); static int socket_is_still_usable(jb_socket sfd); /********************************************************************* * * 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; log_error(LOG_LEVEL_INFO, "Support for 'Connection: keep-alive' is experimental." #ifndef HAVE_POLL " Detecting already dead connections might not work" " correctly on your platform." #endif /* ndef HAVE_POLL */ ); 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 connection for reuse later on. * * Parameters : * 1 : sfd = Open socket to remember. * 2 : http = The destination for the connection. * 3 : fwd = The forwarder settings used. * * Returns : void * *********************************************************************/ void remember_connection(jb_socket sfd, const struct http_request *http, const struct forward_spec *fwd) { unsigned int slot = 0; int free_slot_found = FALSE; assert(sfd != JB_INVALID_SOCKET); if (mark_connection_unused(sfd)) { 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.", sfd, http->host, http->port, slot); free_slot_found = TRUE; break; } } if (!free_slot_found) { log_error(LOG_LEVEL_CONNECT, "No free slots found to remembering socket for %s:%d. Last slot %d.", http->host, http->port, slot); privoxy_mutex_unlock(&connection_reuse_mutex); close_socket(sfd); return; } assert(NULL != http->host); reusable_connection[slot].host = strdup(http->host); if (NULL == reusable_connection[slot].host) { log_error(LOG_LEVEL_FATAL, "Out of memory saving socket."); } reusable_connection[slot].sfd = sfd; reusable_connection[slot].port = http->port; reusable_connection[slot].in_use = 0; reusable_connection[slot].timestamp = time(NULL); assert(NULL != fwd); assert(reusable_connection[slot].gateway_host == NULL); assert(reusable_connection[slot].gateway_port == 0); 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 = fwd->type; if (NULL != fwd->gateway_host) { reusable_connection[slot].gateway_host = strdup(fwd->gateway_host); if (NULL == reusable_connection[slot].gateway_host) { log_error(LOG_LEVEL_FATAL, "Out of memory saving gateway_host."); } } else { reusable_connection[slot].gateway_host = NULL; } reusable_connection[slot].gateway_port = fwd->gateway_port; if (NULL != fwd->forward_host) { reusable_connection[slot].forward_host = strdup(fwd->forward_host); if (NULL == reusable_connection[slot].forward_host) { log_error(LOG_LEVEL_FATAL, "Out of memory saving forward_host."); } } else { reusable_connection[slot].forward_host = NULL; } reusable_connection[slot].forward_port = fwd->forward_port; privoxy_mutex_unlock(&connection_reuse_mutex); } /********************************************************************* * * Function : mark_connection_closed * * Description : Marks a reused connection closed. * Must be called with connection_reuse_mutex locked. * * Parameters : * 1 : closed_connection = The connection to mark as closed. * * Returns : void * *********************************************************************/ static 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->forwarder_type = SOCKS_NONE; freez(closed_connection->gateway_host); closed_connection->gateway_port = 0; freez(closed_connection->forward_host); closed_connection->forward_port = 0; } /********************************************************************* * * 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]); privoxy_mutex_unlock(&connection_reuse_mutex); return; } } log_error(LOG_LEVEL_CONNECT, "Socket %d already forgotten or never remembered.", sfd); privoxy_mutex_unlock(&connection_reuse_mutex); } /********************************************************************* * * 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. * *********************************************************************/ static int connection_destination_matches(const struct reusable_connection *connection, const struct http_request *http, const struct forward_spec *fwd) { /* XXX: Start of duplicated checks for debugging purposes. */ if (strcmpic(connection->host, http->host)) { return FALSE; } if (connection->forwarder_type != fwd->type) { log_error(LOG_LEVEL_CONNECT, "Type mismatch: %d %d (%s)", connection->forwarder_type, fwd->type, http->host); return FALSE; } if (connection->gateway_port != fwd->gateway_port) { log_error(LOG_LEVEL_CONNECT, "Gateway port mismatch: %d %d (%s)", connection->gateway_port, fwd->gateway_port, http->host); return FALSE; } if (connection->forward_port != fwd->forward_port) { log_error(LOG_LEVEL_CONNECT, "Forward port mismatch: %d %d (%s)", connection->forward_port, fwd->forward_port, http->host); return FALSE; } if (connection->forward_port != fwd->forward_port) { log_error(LOG_LEVEL_CONNECT, "Server port mismatch: %d %d (%s)", connection->forward_port, fwd->forward_port, http->host); return FALSE; } /* XXX: End of duplicated checks for debugging purposes. */ 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 (( (NULL != connection->gateway_host) && (NULL != fwd->gateway_host) && strcmpic(connection->gateway_host, fwd->gateway_host)) && (connection->gateway_host != fwd->gateway_host)) { log_error(LOG_LEVEL_CONNECT, "Gateway mismatch."); return FALSE; } if (( (NULL != connection->forward_host) && (NULL != fwd->forward_host) && strcmpic(connection->forward_host, fwd->forward_host)) && (connection->forward_host != fwd->forward_host)) { log_error(LOG_LEVEL_CONNECT, "Forwarding proxy mismatch."); return FALSE; } return (!strcmpic(connection->host, http->host)); } /********************************************************************* * * Function : close_unusable_connections * * Description : Closes remembered connections that have timed * out or have been closed on the other side. * * Parameters : none * * Returns : void * *********************************************************************/ static void close_unusable_connections(void) { unsigned int slot = 0; 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; if (CONNECTION_KEEP_ALIVE_TIMEOUT < time_open) { log_error(LOG_LEVEL_CONNECT, "The connection to %s:%d in slot %d timed out. Closing.", reusable_connection[slot].host, reusable_connection[slot].port, slot); close_socket(reusable_connection[slot].sfd); mark_connection_closed(&reusable_connection[slot]); continue; } if (!socket_is_still_usable(reusable_connection[slot].sfd)) { log_error(LOG_LEVEL_CONNECT, "Socket %d for %s:%d in slot %d is no longer usable. Closing.", reusable_connection[slot].sfd, reusable_connection[slot].host, reusable_connection[slot].port, slot); close_socket(reusable_connection[slot].sfd); mark_connection_closed(&reusable_connection[slot]); continue; } } } } /********************************************************************* * * Function : socket_is_still_usable * * Description : Decides whether or not an open socket is still usable. * * Parameters : * 1 : sfd = The socket to check. * * Returns : TRUE for yes, otherwise FALSE. * *********************************************************************/ static int socket_is_still_usable(jb_socket sfd) { #ifdef HAVE_POLL int poll_result; struct pollfd poll_fd[1]; memset(poll_fd, 0, sizeof(poll_fd)); poll_fd[0].fd = sfd; poll_fd[0].events = POLLIN; poll_result = poll(poll_fd, 1, 0); if (-1 != poll_result) { return !(poll_fd[0].revents & POLLIN); } else { log_error(LOG_LEVEL_CONNECT, "Polling socket %d failed.", sfd); return FALSE; } #else fd_set readable_fds; struct timeval timeout; int ret; int socket_is_alive = 0; memset(&timeout, '\0', sizeof(timeout)); FD_ZERO(&readable_fds); FD_SET(sfd, &readable_fds); ret = select((int)sfd+1, &readable_fds, NULL, NULL, &timeout); if (ret < 0) { log_error(LOG_LEVEL_ERROR, "select() failed!: %E"); } /* * XXX: I'm not sure why !FD_ISSET() works, * but apparently it does. */ socket_is_alive = !FD_ISSET(sfd, &readable_fds); return socket_is_alive; #endif /* def HAVE_POLL */ } /********************************************************************* * * 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; privoxy_mutex_lock(&connection_reuse_mutex); close_unusable_connections(); 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.", sfd, reusable_connection[slot].host, reusable_connection[slot].port, slot); break; } } } privoxy_mutex_unlock(&connection_reuse_mutex); return sfd; } /********************************************************************* * * Function : mark_connection_unused * * Description : Gives a remembered connection free for reuse. * * Parameters : * 1 : sfd = The socket belonging to the connection in question. * * Returns : TRUE => Socket found and marked as unused. * FALSE => Socket not found. * *********************************************************************/ static int mark_connection_unused(jb_socket sfd) { unsigned int slot = 0; int socket_found = FALSE; 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); socket_found = TRUE; log_error(LOG_LEVEL_CONNECT, "Marking open socket %d for %s:%d in slot %d as unused.", sfd, reusable_connection[slot].host, reusable_connection[slot].port, slot); reusable_connection[slot].in_use = 0; reusable_connection[slot].timestamp = time(NULL); break; } } privoxy_mutex_unlock(&connection_reuse_mutex); return socket_found; } #endif /* def FEATURE_CONNECTION_KEEP_ALIVE */ /********************************************************************* * * 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_KEEP_ALIVE sfd = get_reusable_connection(http, fwd); if (JB_INVALID_SOCKET == sfd) { log_error(LOG_LEVEL_CONNECT, "No reusable socket for %s:%d found. Opening a new one.", http->host, http->port); } else { return sfd; } #endif /* def FEATURE_CONNECTION_KEEP_ALIVE */ /* 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: 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: sfd = socks5_connect(fwd, dest_host, dest_port, csp); break; default: /* Should never get here */ log_error(LOG_LEVEL_FATAL, "SOCKS4 impossible internal error - bad SOCKS type."); } return sfd; } /********************************************************************* * * 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 int 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); /* pass the request to the socks server */ sfd = connect_to(fwd->gateway_host, fwd->gateway_port, csp); if (sfd == JB_INVALID_SOCKET) { /* * XXX: connect_to should fill in the exact reason. * Most likely resolving the IP of the forwarder failed. */ errstr = "connect_to failed: see logfile for details"; err = 1; } 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 (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 SOCKS_REQUEST_GRANTED: return(sfd); break; case SOCKS_REQUEST_REJECT: errstr = "SOCKS request rejected or failed."; errno = EINVAL; break; case SOCKS_REQUEST_IDENT_FAILED: errstr = "SOCKS request rejected because " "SOCKS server cannot connect to identd on the client."; errno = EACCES; break; case SOCKS_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. * *********************************************************************/ static const char *translate_socks5_error(int socks_error) { switch (socks_error) { /* XXX: these should be more descriptive */ case SOCKS5_REQUEST_FAILED: return "SOCKS5 request failed"; case SOCKS5_REQUEST_DENIED: return "SOCKS5 request denied"; case SOCKS5_REQUEST_NETWORK_UNREACHABLE: return "SOCKS5 network unreachable"; case SOCKS5_REQUEST_HOST_UNREACHABLE: return "SOCKS5 host unreachable"; case SOCKS5_REQUEST_CONNECTION_REFUSED: return "SOCKS5 connection refused"; case SOCKS5_REQUEST_TTL_EXPIRED: return "SOCKS5 TTL expired"; case SOCKS5_REQUEST_PROTOCOL_ERROR: return "SOCKS5 client protocol error"; case SOCKS5_REQUEST_BAD_ADDRESS_TYPE: return "SOCKS5 domain names unsupported"; case SOCKS5_REQUEST_GRANTED: return "everything's peachy"; default: return "SOCKS5 negotiation protocol error"; } } /********************************************************************* * * Function : socks5_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. * * 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 socks5_connect(const struct forward_spec *fwd, const char *target_host, int target_port, struct client_state *csp) { int err = 0; char cbuf[300]; char sbuf[30]; size_t client_pos = 0; int server_size = 0; size_t hostlen = 0; jb_socket sfd; const char *errstr = NULL; assert(fwd->gateway_host); if ((fwd->gateway_host == NULL) || (*fwd->gateway_host == '\0')) { errstr = "NULL gateway host specified"; err = 1; } if (fwd->gateway_port <= 0) { /* * XXX: currently this can't happen because in * case of invalid gateway ports we use the defaults. * Of course we really shouldn't do that. */ errstr = "invalid gateway port specified"; err = 1; } hostlen = strlen(target_host); if (hostlen > 255) { errstr = "target host name is longer than 255 characters"; err = 1; } if (fwd->type != SOCKS_5) { /* Should never get here */ log_error(LOG_LEVEL_FATAL, "SOCKS5 impossible internal error - bad SOCKS type"); err = 1; } if (err) { errno = EINVAL; assert(errstr != NULL); log_error(LOG_LEVEL_CONNECT, "socks5_connect: %s", errstr); csp->error_message = strdup(errstr); return(JB_INVALID_SOCKET); } /* pass the request to the socks server */ sfd = connect_to(fwd->gateway_host, fwd->gateway_port, csp); if (sfd == JB_INVALID_SOCKET) { errstr = "socks5 server unreachable"; log_error(LOG_LEVEL_CONNECT, "socks5_connect: %s", errstr); csp->error_message = strdup(errstr); return(JB_INVALID_SOCKET); } client_pos = 0; cbuf[client_pos++] = '\x05'; /* Version */ cbuf[client_pos++] = '\x01'; /* One authentication method supported */ cbuf[client_pos++] = '\x00'; /* The no authentication authentication method */ if (write_socket(sfd, cbuf, client_pos)) { errstr = "SOCKS5 negotiation write failed"; csp->error_message = strdup(errstr); log_error(LOG_LEVEL_CONNECT, "%s", errstr); close_socket(sfd); return(JB_INVALID_SOCKET); } if (read_socket(sfd, sbuf, sizeof(sbuf)) != 2) { errstr = "SOCKS5 negotiation read failed"; err = 1; } if (!err && (sbuf[0] != '\x05')) { errstr = "SOCKS5 negotiation protocol version error"; err = 1; } if (!err && (sbuf[1] == '\xff')) { errstr = "SOCKS5 authentication required"; err = 1; } if (!err && (sbuf[1] != '\x00')) { errstr = "SOCKS5 negotiation protocol error"; err = 1; } if (err) { assert(errstr != NULL); log_error(LOG_LEVEL_CONNECT, "socks5_connect: %s", errstr); csp->error_message = strdup(errstr); close_socket(sfd); errno = EINVAL; return(JB_INVALID_SOCKET); } client_pos = 0; cbuf[client_pos++] = '\x05'; /* Version */ cbuf[client_pos++] = '\x01'; /* TCP connect */ cbuf[client_pos++] = '\x00'; /* Reserved, must be 0x00 */ cbuf[client_pos++] = '\x03'; /* Address is domain name */ cbuf[client_pos++] = (char)(hostlen & 0xffu); assert(sizeof(cbuf) - client_pos > 255); /* Using strncpy because we really want the nul byte padding. */ strncpy(cbuf + client_pos, target_host, sizeof(cbuf) - client_pos); client_pos += (hostlen & 0xffu); cbuf[client_pos++] = (char)((target_port >> 8) & 0xff); cbuf[client_pos++] = (char)((target_port ) & 0xff); if (write_socket(sfd, cbuf, client_pos)) { errstr = "SOCKS5 negotiation read failed"; csp->error_message = strdup(errstr); log_error(LOG_LEVEL_CONNECT, "%s", errstr); close_socket(sfd); errno = EINVAL; return(JB_INVALID_SOCKET); } server_size = read_socket(sfd, sbuf, sizeof(sbuf)); if (server_size < 3) { errstr = "SOCKS5 negotiation read failed"; err = 1; } else if (server_size > 20) { /* This is somewhat unexpected but doesn't realy matter. */ log_error(LOG_LEVEL_CONNECT, "socks5_connect: read %d bytes " "from socks server. Would have accepted up to %d.", server_size, sizeof(sbuf)); } if (!err && (sbuf[0] != '\x05')) { errstr = "SOCKS5 negotiation protocol version error"; err = 1; } if (!err && (sbuf[2] != '\x00')) { errstr = "SOCKS5 negotiation protocol error"; err = 1; } if (!err) { if (sbuf[1] == SOCKS5_REQUEST_GRANTED) { return(sfd); } errstr = translate_socks5_error(sbuf[1]); err = 1; } assert(errstr != NULL); csp->error_message = strdup(errstr); log_error(LOG_LEVEL_CONNECT, "socks5_connect: %s", errstr); close_socket(sfd); errno = EINVAL; return(JB_INVALID_SOCKET); } /* Local Variables: tab-width: 3 end: */