tinyproxy/src/sock.c

/* tinyproxy - A fast light-weight HTTP proxy
 * Copyright (C) 1998 Steven Young <sdyoung@miranda.org>
 * Copyright (C) 1999, 2004 Robert James Kaes <rjkaes@users.sourceforge.net>
 * Copyright (C) 2000 Chris Lightfoot <chris@ex-parrot.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.
 *
 * 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.
 */

/* Sockets are created and destroyed here. When a new connection comes in from
 * a client, we need to copy the socket and the create a second socket to the
 * remote server the client is trying to connect to. Also, the listening
 * socket is created and destroyed here. Sounds more impressive than it
 * actually is.
 */

#include "tinyproxy.h"

#include "log.h"
#include "heap.h"
#include "network.h"
#include "sock.h"
#include "text.h"

/*
 * Bind the given socket to the supplied address.  The socket is
 * returned if the bind succeeded.  Otherwise, -1 is returned
 * to indicate an error.
 */
static int
bind_socket (int sockfd, const char *addr)
{
  struct addrinfo hints, *res, *ressave;

  assert (sockfd >= 0);
  assert (addr != NULL && strlen (addr) != 0);

  memset (&hints, 0, sizeof (struct addrinfo));
  hints.ai_family = AF_UNSPEC;
  hints.ai_socktype = SOCK_STREAM;

  /* The local port it not important */
  if (getaddrinfo (addr, NULL, &hints, &res) != 0)
    return -1;

  ressave = res;

  /* Loop through the addresses and try to bind to each */
  do
    {
      if (bind (sockfd, res->ai_addr, res->ai_addrlen) == 0)
	break;			/* success */
    }
  while ((res = res->ai_next) != NULL);

  freeaddrinfo (ressave);
  if (res == NULL)		/* was not able to bind to any address */
    return -1;

  return sockfd;
}

/*
 * Open a connection to a remote host.  It's been re-written to use
 * the getaddrinfo() library function, which allows for a protocol
 * independent implementation (mostly for IPv4 and IPv6 addresses.)
 */
int
opensock (const char *host, int port, const char *bind_to)
{
  int sockfd, n;
  struct addrinfo hints, *res, *ressave;
  char portstr[6];

  assert (host != NULL);
  assert (port > 0);

  memset (&hints, 0, sizeof (struct addrinfo));
  hints.ai_family = AF_UNSPEC;
  hints.ai_socktype = SOCK_STREAM;

  snprintf (portstr, sizeof (portstr), "%d", port);

  n = getaddrinfo (host, portstr, &hints, &res);
  if (n != 0)
    {
      log_message (LOG_ERR, "opensock: Could not retrieve info for %s", host);
      return -1;
    }

  ressave = res;
  do
    {
      sockfd = socket (res->ai_family, res->ai_socktype, res->ai_protocol);
      if (sockfd < 0)
	continue;		/* ignore this one */

      /* Bind to the specified address */
      if (bind_to)
	{
	  if (bind_socket (sockfd, bind_to) < 0)
	    {
	      close (sockfd);
	      continue;		/* can't bind, so try again */
	    }
	}
      else if (config.bind_address)
	{
	  if (bind_socket (sockfd, config.bind_address) < 0)
	    {
	      close (sockfd);
	      continue;		/* can't bind, so try again */
	    }
	}

      if (connect (sockfd, res->ai_addr, res->ai_addrlen) == 0)
	break;			/* success */

      close (sockfd);
    }
  while ((res = res->ai_next) != NULL);

  freeaddrinfo (ressave);
  if (res == NULL)
    {
      log_message (LOG_ERR,
		   "opensock: Could not establish a connection to %s", host);
      return -1;
    }

  return sockfd;
}

/*
 * Set the socket to non blocking -rjkaes
 */
int
socket_nonblocking (int sock)
{
  int flags;

  assert (sock >= 0);

  flags = fcntl (sock, F_GETFL, 0);
  return fcntl (sock, F_SETFL, flags | O_NONBLOCK);
}

/*
 * Set the socket to blocking -rjkaes
 */
int
socket_blocking (int sock)
{
  int flags;

  assert (sock >= 0);

  flags = fcntl (sock, F_GETFL, 0);
  return fcntl (sock, F_SETFL, flags & ~O_NONBLOCK);
}

/*
 * Start listening to a socket. Create a socket with the selected port.
 * The size of the socket address will be returned to the caller through
 * the pointer, while the socket is returned as a default return.
 *	- rjkaes
 */
int
listen_sock (uint16_t port, socklen_t * addrlen)
{
  int listenfd;
  const int on = 1;
  struct sockaddr_in addr;

  assert (port > 0);
  assert (addrlen != NULL);

  listenfd = socket (AF_INET, SOCK_STREAM, 0);
  setsockopt (listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof (on));

  memset (&addr, 0, sizeof (addr));
  addr.sin_family = AF_INET;
  addr.sin_port = htons (port);

  if (config.ipAddr)
    {
      addr.sin_addr.s_addr = inet_addr (config.ipAddr);
    }
  else
    {
      addr.sin_addr.s_addr = inet_addr ("0.0.0.0");
    }

  if (bind (listenfd, (struct sockaddr *) &addr, sizeof (addr)) < 0)
    {
      log_message (LOG_ERR,
		   "Unable to bind listening socket because of %s",
		   strerror (errno));
      return -1;
    }

  if (listen (listenfd, MAXLISTEN) < 0)
    {
      log_message (LOG_ERR,
		   "Unable to start listening socket because of %s",
		   strerror (errno));
      return -1;
    }

  *addrlen = sizeof (addr);

  return listenfd;
}

/*
 * Takes a socket descriptor and returns the socket's IP address.
 */
int
getsock_ip (int fd, char *ipaddr)
{
  struct sockaddr_storage name;
  socklen_t namelen = sizeof (name);

  assert (fd >= 0);

  if (getsockname (fd, (struct sockaddr *) &name, &namelen) != 0)
    {
      log_message (LOG_ERR, "getsock_ip: getsockname() error: %s",
		   strerror (errno));
      return -1;
    }

  if (get_ip_string ((struct sockaddr *) &name, ipaddr, IP_LENGTH) == NULL)
    return -1;

  return 0;
}

/*
 * Return the peer's socket information.
 */
int
getpeer_information (int fd, char *ipaddr, char *string_addr)
{
  struct sockaddr_storage sa;
  socklen_t salen = sizeof sa;

  assert (fd >= 0);
  assert (ipaddr != NULL);
  assert (string_addr != NULL);

  /* Set the strings to default values */
  ipaddr[0] = '\0';
  strlcpy (string_addr, "[unknown]", HOSTNAME_LENGTH);

  /* Look up the IP address */
  if (getpeername (fd, (struct sockaddr *) &sa, &salen) != 0)
    return -1;

  if (get_ip_string ((struct sockaddr *) &sa, ipaddr, IP_LENGTH) == NULL)
    return -1;

  /* Get the full host name */
  return getnameinfo ((struct sockaddr *) &sa, salen,
		      string_addr, HOSTNAME_LENGTH, NULL, 0, 0);
}