tinyproxy/src/transparent-proxy.c

/* tinyproxy - A fast light-weight HTTP proxy
 * Copyright (C) 2002       Petr Lampa <lampa@fit.vutbr.cz>
 * Copyright (C) 2008       Robert James Kaes <rjk@wormbytes.ca>
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

/*
 * This section of code is used for the transparent proxy option.  You will
 * need to configure your firewall to redirect all connections for HTTP
 * traffic to tinyproxy for this to work properly.
 */

#include "tinyproxy.h"

#include "transparent-proxy.h"
#include "conns.h"
#include "heap.h"
#include "html-error.h"
#include "log.h"
#include "reqs.h"

/*
 * Build a URL from parts.
 */
static int
build_url(char **url, const char *host, int port, const char *path)
{
        int len;

        assert(url != NULL);
        assert(host != NULL);
        assert(port > 0 && port < 32768);
        assert(path != NULL);

        len = strlen(host) + strlen(path) + 14;
        *url = safemalloc(len);
        if (*url == NULL)
                return -1;

        return snprintf(*url, len, "http://%s:%d%s", host, port, path);
}


int
do_transparent_proxy(struct conn_s *connptr, hashmap_t hashofheaders,
                struct request_s *request, struct config_s *conf, char *url)
{
        socklen_t length;
        char *data;
        
        length =
                hashmap_entry_by_key(hashofheaders, "host", (void **)&data);
        if (length <= 0) {
                struct sockaddr_in dest_addr;
        
                if (getsockname
                        (connptr->client_fd, (struct sockaddr *)&dest_addr,
                        &length) < 0) {
                        log_message(LOG_ERR,
                                        "process_request: cannot get destination IP for %d",
                                        connptr->client_fd);
                        indicate_http_error(connptr, 400, "Bad Request",
                                                "detail",
                                                "Unknown destination",
                                                "url", url, NULL);
                        return 0;
                }
                request->host = safemalloc(17);
                strcpy(request->host, inet_ntoa(dest_addr.sin_addr));
                request->port = ntohs(dest_addr.sin_port);
                request->path = safemalloc(strlen(url) + 1);
                strcpy(request->path, url);
                safefree(url);
                build_url(&url, request->host, request->port,
                                request->path);
                log_message(LOG_INFO,
                                "process_request: trans IP %s %s for %d",
                                request->method, url, connptr->client_fd);
        } else {
                request->host = safemalloc(length + 1);
                if (sscanf
                        (data, "%[^:]:%hu", request->host,
                        &request->port) != 2) {
                        strcpy(request->host, data);
                        request->port = HTTP_PORT;
                }
                request->path = safemalloc(strlen(url) + 1);
                strcpy(request->path, url);
                safefree(url);
                build_url(&url, request->host, request->port,
                                request->path);
                log_message(LOG_INFO,
                                "process_request: trans Host %s %s for %d",
                                request->method, url, connptr->client_fd);
        }
        if (conf->ipAddr && strcmp(request->host, conf->ipAddr) == 0) {
                log_message(LOG_ERR,
                                "process_request: destination IP is localhost %d",
                                connptr->client_fd);
                indicate_http_error(connptr, 400, "Bad Request",
                                        "detail",
                                        "You tried to connect to the machine the proxy is running on",
                                        "url", url, NULL);
                return 0;
        }

        return 1;
}