/* 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;
}