X-Git-Url: http://sjero.net/git/?a=blobdiff_plain;f=src%2Fconnect.c;h=ab1fd08e7a03e7430136622db3ab54e3b274ac05;hb=4d7c5e087b2bc82c9f503dff003916d1047903ce;hp=28ce204347ab552f052f7bd01732ba8499d7c84d;hpb=1396b300550d9b5ca3b4b3e4e3776a1456024f73;p=wget

diff --git a/src/connect.c b/src/connect.c
index 28ce2043..ab1fd08e 100644
--- a/src/connect.c
+++ b/src/connect.c
@@ -1,323 +1,956 @@
 /* Establishing and handling network connections.
-   Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
+   Copyright (C) 1996-2006 Free Software Foundation, Inc.
 
-This file is part of Wget.
+This file is part of GNU Wget.
 
-This program is free software; you can redistribute it and/or modify
+GNU Wget 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.
+the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
 
-This program is distributed in the hope that it will be useful,
+GNU Wget 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., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+along with Wget.  If not, see <http://www.gnu.org/licenses/>.
+
+In addition, as a special exception, the Free Software Foundation
+gives permission to link the code of its release of Wget with the
+OpenSSL project's "OpenSSL" library (or with modified versions of it
+that use the same license as the "OpenSSL" library), and distribute
+the linked executables.  You must obey the GNU General Public License
+in all respects for all of the code used other than "OpenSSL".  If you
+modify this file, you may extend this exception to your version of the
+file, but you are not obligated to do so.  If you do not wish to do
+so, delete this exception statement from your version.  */
 
 #include <config.h>
 
 #include <stdio.h>
-#include <sys/types.h>
+#include <stdlib.h>
 #ifdef HAVE_UNISTD_H
 # include <unistd.h>
 #endif
+#include <assert.h>
 
-#ifdef WINDOWS
-# include <winsock.h>
-#else
+#ifndef WINDOWS
 # include <sys/socket.h>
 # include <netdb.h>
 # include <netinet/in.h>
-# include <arpa/inet.h>
-#endif /* WINDOWS */
+# ifndef __BEOS__
+#  include <arpa/inet.h>
+# endif
+#endif /* not WINDOWS */
 
 #include <errno.h>
-#ifdef HAVE_STRING_H
-# include <string.h>
-#else
-# include <strings.h>
-#endif /* HAVE_STRING_H */
+#include <string.h>
 #ifdef HAVE_SYS_SELECT_H
 # include <sys/select.h>
 #endif /* HAVE_SYS_SELECT_H */
 
 #include "wget.h"
-#include "connect.h"
+#include "utils.h"
 #include "host.h"
+#include "connect.h"
+#include "hash.h"
+
+/* Define sockaddr_storage where unavailable (presumably on IPv4-only
+   hosts).  */
 
-#ifndef errno
-extern int errno;
+#ifndef ENABLE_IPV6
+# ifndef HAVE_STRUCT_SOCKADDR_STORAGE
+#  define sockaddr_storage sockaddr_in
+# endif
+#endif /* ENABLE_IPV6 */
+
+/* Fill SA as per the data in IP and PORT.  SA shoult point to struct
+   sockaddr_storage if ENABLE_IPV6 is defined, to struct sockaddr_in
+   otherwise.  */
+
+static void
+sockaddr_set_data (struct sockaddr *sa, const ip_address *ip, int port)
+{
+  switch (ip->family)
+    {
+    case AF_INET:
+      {
+	struct sockaddr_in *sin = (struct sockaddr_in *)sa;
+	xzero (*sin);
+	sin->sin_family = AF_INET;
+	sin->sin_port = htons (port);
+	sin->sin_addr = ip->data.d4;
+	break;
+      }
+#ifdef ENABLE_IPV6
+    case AF_INET6:
+      {
+	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa;
+	xzero (*sin6);
+	sin6->sin6_family = AF_INET6;
+	sin6->sin6_port = htons (port);
+	sin6->sin6_addr = ip->data.d6;
+#ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
+	sin6->sin6_scope_id = ip->ipv6_scope;
 #endif
+	break;
+      }
+#endif /* ENABLE_IPV6 */
+    default:
+      abort ();
+    }
+}
+
+/* Get the data of SA, specifically the IP address and the port.  If
+   you're not interested in one or the other information, pass NULL as
+   the pointer.  */
 
-/* Variables shared by bindport and acceptport: */
-static int msock = -1;
-static struct sockaddr *addr;
+static void
+sockaddr_get_data (const struct sockaddr *sa, ip_address *ip, int *port)
+{
+  switch (sa->sa_family)
+    {
+    case AF_INET:
+      {
+	struct sockaddr_in *sin = (struct sockaddr_in *)sa;
+	if (ip)
+	  {
+	    ip->family = AF_INET;
+	    ip->data.d4 = sin->sin_addr;
+	  }
+	if (port)
+	  *port = ntohs (sin->sin_port);
+	break;
+      }
+#ifdef ENABLE_IPV6
+    case AF_INET6:
+      {
+	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa;
+	if (ip)
+	  {
+	    ip->family = AF_INET6;
+	    ip->data.d6 = sin6->sin6_addr;
+#ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
+	    ip->ipv6_scope = sin6->sin6_scope_id;
+#endif
+	  }
+	if (port)
+	  *port = ntohs (sin6->sin6_port);
+	break;
+      }
+#endif
+    default:
+      abort ();
+    }
+}
 
+/* Return the size of the sockaddr structure depending on its
+   family.  */
 
-/* Create an internet connection to HOSTNAME on PORT.  The created
-   socket will be stored to *SOCK.  */
-uerr_t
-make_connection (int *sock, char *hostname, unsigned short port)
+static socklen_t
+sockaddr_size (const struct sockaddr *sa)
 {
-  struct sockaddr_in sock_name;
-  /* struct hostent *hptr; */
-
-  /* Get internet address of the host.  We can do it either by calling
-     ngethostbyname, or by calling store_hostaddress, from host.c.
-     storehostaddress is better since it caches calls to
-     gethostbyname.  */
-#if 1
-  if (!store_hostaddress ((unsigned char *)&sock_name.sin_addr, hostname))
-    return HOSTERR;
-#else  /* never */
-  if (!(hptr = ngethostbyname (hostname)))
-    return HOSTERR;
-  /* Copy the address of the host to socket description.  */
-  memcpy (&sock_name.sin_addr, hptr->h_addr, hptr->h_length);
-#endif /* never */
-
-  /* Set port and protocol */
-  sock_name.sin_family = AF_INET;
-  sock_name.sin_port = htons (port);
-
-  /* Make an internet socket, stream type.  */
-  if ((*sock = socket (AF_INET, SOCK_STREAM, 0)) == -1)
-    return CONSOCKERR;
-
-  if (opt.bind_address != NULL)
+  switch (sa->sa_family)
     {
-      /* Bind the client side to the requested address. */
-      if (bind (*sock, (struct sockaddr *) opt.bind_address,
-		sizeof (*opt.bind_address)))
-	return CONSOCKERR;
+    case AF_INET:
+      return sizeof (struct sockaddr_in);
+#ifdef ENABLE_IPV6
+    case AF_INET6:
+      return sizeof (struct sockaddr_in6);
+#endif
+    default:
+      abort ();
     }
+}
+
+/* Resolve the bind address specified via --bind-address and store it
+   to SA.  The resolved value is stored in a static variable and
+   reused after the first invocation of this function.
 
-  /* Connect the socket to the remote host.  */
-  if (connect (*sock, (struct sockaddr *) &sock_name, sizeof (sock_name)))
+   Returns true on success, false on failure.  */
+
+static bool
+resolve_bind_address (struct sockaddr *sa)
+{
+  struct address_list *al;
+
+  /* Make sure this is called only once.  opt.bind_address doesn't
+     change during a Wget run.  */
+  static bool called, should_bind;
+  static ip_address ip;
+  if (called)
     {
-      if (errno == ECONNREFUSED)
-	return CONREFUSED;
+      if (should_bind)
+	sockaddr_set_data (sa, &ip, 0);
+      return should_bind;
+    }
+  called = true;
+
+  al = lookup_host (opt.bind_address, LH_BIND | LH_SILENT);
+  if (!al)
+    {
+      /* #### We should be able to print the error message here. */
+      logprintf (LOG_NOTQUIET,
+		 _("%s: unable to resolve bind address `%s'; disabling bind.\n"),
+		 exec_name, opt.bind_address);
+      should_bind = false;
+      return false;
+    }
+
+  /* Pick the first address in the list and use it as bind address.
+     Perhaps we should try multiple addresses in succession, but I
+     don't think that's necessary in practice.  */
+  ip = *address_list_address_at (al, 0);
+  address_list_release (al);
+
+  sockaddr_set_data (sa, &ip, 0);
+  should_bind = true;
+  return true;
+}
+
+struct cwt_context {
+  int fd;
+  const struct sockaddr *addr;
+  socklen_t addrlen;
+  int result;
+};
+
+static void
+connect_with_timeout_callback (void *arg)
+{
+  struct cwt_context *ctx = (struct cwt_context *)arg;
+  ctx->result = connect (ctx->fd, ctx->addr, ctx->addrlen);
+}
+
+/* Like connect, but specifies a timeout.  If connecting takes longer
+   than TIMEOUT seconds, -1 is returned and errno is set to
+   ETIMEDOUT.  */
+
+static int
+connect_with_timeout (int fd, const struct sockaddr *addr, socklen_t addrlen,
+		      double timeout)
+{
+  struct cwt_context ctx;
+  ctx.fd = fd;
+  ctx.addr = addr;
+  ctx.addrlen = addrlen;
+
+  if (run_with_timeout (timeout, connect_with_timeout_callback, &ctx))
+    {
+      errno = ETIMEDOUT;
+      return -1;
+    }
+  if (ctx.result == -1 && errno == EINTR)
+    errno = ETIMEDOUT;
+  return ctx.result;
+}
+
+/* Connect via TCP to the specified address and port.
+
+   If PRINT is non-NULL, it is the host name to print that we're
+   connecting to.  */
+
+int
+connect_to_ip (const ip_address *ip, int port, const char *print)
+{
+  struct sockaddr_storage ss;
+  struct sockaddr *sa = (struct sockaddr *)&ss;
+  int sock;
+
+  /* If PRINT is non-NULL, print the "Connecting to..." line, with
+     PRINT being the host name we're connecting to.  */
+  if (print)
+    {
+      const char *txt_addr = print_address (ip);
+      if (print && 0 != strcmp (print, txt_addr))
+	logprintf (LOG_VERBOSE, _("Connecting to %s|%s|:%d... "),
+		   escnonprint (print), txt_addr, port);
       else
-	return CONERROR;
+	logprintf (LOG_VERBOSE, _("Connecting to %s:%d... "), txt_addr, port);
+    }
+
+  /* Store the sockaddr info to SA.  */
+  sockaddr_set_data (sa, ip, port);
+
+  /* Create the socket of the family appropriate for the address.  */
+  sock = socket (sa->sa_family, SOCK_STREAM, 0);
+  if (sock < 0)
+    goto err;
+
+#if defined(ENABLE_IPV6) && defined(IPV6_V6ONLY)
+  if (opt.ipv6_only) {
+    int on = 1;
+    /* In case of error, we will go on anyway... */
+    int err = setsockopt (sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof (on));
+    IF_DEBUG
+      if (err < 0) 
+	DEBUGP (("Failed setting IPV6_V6ONLY: %s", strerror (errno)));
+  }
+#endif
+
+  /* For very small rate limits, set the buffer size (and hence,
+     hopefully, the kernel's TCP window size) to the per-second limit.
+     That way we should never have to sleep for more than 1s between
+     network reads.  */
+  if (opt.limit_rate && opt.limit_rate < 8192)
+    {
+      int bufsize = opt.limit_rate;
+      if (bufsize < 512)
+	bufsize = 512;		/* avoid pathologically small values */
+#ifdef SO_RCVBUF
+      setsockopt (sock, SOL_SOCKET, SO_RCVBUF,
+		  (void *)&bufsize, (socklen_t)sizeof (bufsize));
+#endif
+      /* When we add limit_rate support for writing, which is useful
+	 for POST, we should also set SO_SNDBUF here.  */
     }
-  DEBUGP (("Created fd %d.\n", *sock));
-  return NOCONERROR;
+
+  if (opt.bind_address)
+    {
+      /* Bind the client side of the socket to the requested
+	 address.  */
+      struct sockaddr_storage bind_ss;
+      struct sockaddr *bind_sa = (struct sockaddr *)&bind_ss;
+      if (resolve_bind_address (bind_sa))
+	{
+          if (bind (sock, bind_sa, sockaddr_size (bind_sa)) < 0)
+	    goto err;
+	}
+    }
+
+  /* Connect the socket to the remote endpoint.  */
+  if (connect_with_timeout (sock, sa, sockaddr_size (sa),
+			    opt.connect_timeout) < 0)
+    goto err;
+
+  /* Success. */
+  assert (sock >= 0);
+  if (print)
+    logprintf (LOG_VERBOSE, _("connected.\n"));
+  DEBUGP (("Created socket %d.\n", sock));
+  return sock;
+
+ err:
+  {
+    /* Protect errno from possible modifications by close and
+       logprintf.  */
+    int save_errno = errno;
+    if (sock >= 0)
+      fd_close (sock);
+    if (print)
+      logprintf (LOG_VERBOSE, _("failed: %s.\n"), strerror (errno));
+    errno = save_errno;
+    return -1;
+  }
 }
 
-/* Bind the local port PORT.  This does all the necessary work, which
-   is creating a socket, setting SO_REUSEADDR option on it, then
-   calling bind() and listen().  If *PORT is 0, a random port is
-   chosen by the system, and its value is stored to *PORT.  The
-   internal variable MPORT is set to the value of the ensuing master
-   socket.  Call acceptport() to block for and accept a connection.  */
-uerr_t
-bindport (unsigned short *port)
+/* Connect via TCP to a remote host on the specified port.
+
+   HOST is resolved as an Internet host name.  If HOST resolves to
+   more than one IP address, they are tried in the order returned by
+   DNS until connecting to one of them succeeds.  */
+
+int
+connect_to_host (const char *host, int port)
 {
-  int optval = 1;
-  static struct sockaddr_in srv;
-
-  msock = -1;
-  addr = (struct sockaddr *) &srv;
-  if ((msock = socket (AF_INET, SOCK_STREAM, 0)) < 0)
-    return CONSOCKERR;
-  if (setsockopt (msock, SOL_SOCKET, SO_REUSEADDR,
-		  (char *)&optval, sizeof (optval)) < 0)
-    return CONSOCKERR;
-
-  if (opt.bind_address == NULL)
+  int i, start, end;
+  int sock;
+
+  struct address_list *al = lookup_host (host, 0);
+
+ retry:
+  if (!al)
+    return E_HOST;
+
+  address_list_get_bounds (al, &start, &end);
+  for (i = start; i < end; i++)
     {
-      srv.sin_family = AF_INET;
-      srv.sin_addr.s_addr = htonl (INADDR_ANY);
+      const ip_address *ip = address_list_address_at (al, i);
+      sock = connect_to_ip (ip, port, host);
+      if (sock >= 0)
+	{
+	  /* Success. */
+	  address_list_set_connected (al);
+	  address_list_release (al);
+	  return sock;
+	}
+
+      /* The attempt to connect has failed.  Continue with the loop
+	 and try next address. */
+
+      address_list_set_faulty (al, i);
     }
-  else
-    srv = *opt.bind_address;
 
-  srv.sin_port = htons (*port);
-  if (bind (msock, addr, sizeof (struct sockaddr_in)) < 0)
+  /* Failed to connect to any of the addresses in AL. */
+
+  if (address_list_connected_p (al))
+    {
+      /* We connected to AL before, but cannot do so now.  That might
+	 indicate that our DNS cache entry for HOST has expired.  */
+      address_list_release (al);
+      al = lookup_host (host, LH_REFRESH);
+      goto retry;
+    }
+  address_list_release (al);
+
+  return -1;
+}
+
+/* Create a socket, bind it to local interface BIND_ADDRESS on port
+   *PORT, set up a listen backlog, and return the resulting socket, or
+   -1 in case of error.
+
+   BIND_ADDRESS is the address of the interface to bind to.  If it is
+   NULL, the socket is bound to the default address.  PORT should
+   point to the port number that will be used for the binding.  If
+   that number is 0, the system will choose a suitable port, and the
+   chosen value will be written to *PORT.
+
+   Calling accept() on such a socket waits for and accepts incoming
+   TCP connections.  */
+
+int
+bind_local (const ip_address *bind_address, int *port)
+{
+  int sock;
+  struct sockaddr_storage ss;
+  struct sockaddr *sa = (struct sockaddr *)&ss;
+
+  /* For setting options with setsockopt. */
+  int setopt_val = 1;
+  void *setopt_ptr = (void *)&setopt_val;
+  socklen_t setopt_size = sizeof (setopt_val);
+
+  sock = socket (bind_address->family, SOCK_STREAM, 0);
+  if (sock < 0)
+    return -1;
+
+#ifdef SO_REUSEADDR
+  setsockopt (sock, SOL_SOCKET, SO_REUSEADDR, setopt_ptr, setopt_size);
+#endif
+
+  xzero (ss);
+  sockaddr_set_data (sa, bind_address, *port);
+  if (bind (sock, sa, sockaddr_size (sa)) < 0)
     {
-      CLOSE (msock);
-      msock = -1;
-      return BINDERR;
+      fd_close (sock);
+      return -1;
     }
-  DEBUGP (("Master socket fd %d bound.\n", msock));
-  if (!*port)
+  DEBUGP (("Local socket fd %d bound.\n", sock));
+
+  /* If *PORT is 0, find out which port we've bound to.  */
+  if (*port == 0)
     {
-      size_t addrlen = sizeof (struct sockaddr_in);
-      if (getsockname (msock, addr, (int *)&addrlen) < 0)
+      socklen_t addrlen = sockaddr_size (sa);
+      if (getsockname (sock, sa, &addrlen) < 0)
 	{
-	  CLOSE (msock);
-	  msock = -1;
-	  return CONPORTERR;
+	  /* If we can't find out the socket's local address ("name"),
+	     something is seriously wrong with the socket, and it's
+	     unusable for us anyway because we must know the chosen
+	     port.  */
+	  fd_close (sock);
+	  return -1;
 	}
-      *port = ntohs (srv.sin_port);
+      sockaddr_get_data (sa, NULL, port);
+      DEBUGP (("binding to address %s using port %i.\n",
+	       print_address (bind_address), *port));
     }
-  if (listen (msock, 1) < 0)
+  if (listen (sock, 1) < 0)
     {
-      CLOSE (msock);
-      msock = -1;
-      return LISTENERR;
+      fd_close (sock);
+      return -1;
     }
-  return BINDOK;
+  return sock;
 }
 
-#ifdef HAVE_SELECT
-/* Wait for file descriptor FD to be readable, MAXTIME being the
-   timeout in seconds.  If WRITEP is non-zero, checks for FD being
-   writable instead.
+/* Like a call to accept(), but with the added check for timeout.
 
-   Returns 1 if FD is accessible, 0 for timeout and -1 for error in
-   select().  */
-static int
-select_fd (int fd, int maxtime, int writep)
+   In other words, accept a client connection on LOCAL_SOCK, and
+   return the new socket used for communication with the client.
+   LOCAL_SOCK should have been bound, e.g. using bind_local().
+
+   The caller is blocked until a connection is established.  If no
+   connection is established for opt.connect_timeout seconds, the
+   function exits with an error status.  */
+
+int
+accept_connection (int local_sock)
 {
-  fd_set fds, exceptfds;
-  struct timeval timeout;
-
-  FD_ZERO (&fds);
-  FD_SET (fd, &fds);
-  FD_ZERO (&exceptfds);
-  FD_SET (fd, &exceptfds);
-  timeout.tv_sec = maxtime;
-  timeout.tv_usec = 0;
-  /* HPUX reportedly warns here.  What is the correct incantation?  */
-  return select (fd + 1, writep ? NULL : &fds, writep ? &fds : NULL,
-		 &exceptfds, &timeout);
+  int sock;
+
+  /* We don't need the values provided by accept, but accept
+     apparently requires them to be present.  */
+  struct sockaddr_storage ss;
+  struct sockaddr *sa = (struct sockaddr *)&ss;
+  socklen_t addrlen = sizeof (ss);
+
+  if (opt.connect_timeout)
+    {
+      int test = select_fd (local_sock, opt.connect_timeout, WAIT_FOR_READ);
+      if (test == 0)
+	errno = ETIMEDOUT;
+      if (test <= 0)
+	return -1;
+    }
+  sock = accept (local_sock, sa, &addrlen);
+  DEBUGP (("Accepted client at socket %d.\n", sock));
+  return sock;
 }
-#endif /* HAVE_SELECT */
-
-/* Call accept() on MSOCK and store the result to *SOCK.  This assumes
-   that bindport() has been used to initialize MSOCK to a correct
-   value.  It blocks the caller until a connection is established.  If
-   no connection is established for OPT.TIMEOUT seconds, the function
-   exits with an error status.  */
-uerr_t
-acceptport (int *sock)
+
+/* Get the IP address associated with the connection on FD and store
+   it to IP.  Return true on success, false otherwise.
+
+   If ENDPOINT is ENDPOINT_LOCAL, it returns the address of the local
+   (client) side of the socket.  Else if ENDPOINT is ENDPOINT_PEER, it
+   returns the address of the remote (peer's) side of the socket.  */
+
+bool
+socket_ip_address (int sock, ip_address *ip, int endpoint)
 {
-  int addrlen = sizeof (struct sockaddr_in);
+  struct sockaddr_storage storage;
+  struct sockaddr *sockaddr = (struct sockaddr *)&storage;
+  socklen_t addrlen = sizeof (storage);
+  int ret;
+
+  if (endpoint == ENDPOINT_LOCAL)
+    ret = getsockname (sock, sockaddr, &addrlen);
+  else if (endpoint == ENDPOINT_PEER)
+    ret = getpeername (sock, sockaddr, &addrlen);
+  else
+    abort ();
+  if (ret < 0)
+    return false;
 
-#ifdef HAVE_SELECT
-  if (select_fd (msock, opt.timeout, 0) <= 0)
-    return ACCEPTERR;
+  ip->family = sockaddr->sa_family;
+  switch (sockaddr->sa_family)
+    {
+#ifdef ENABLE_IPV6
+    case AF_INET6:
+      {
+	struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)&storage;
+	ip->data.d6 = sa6->sin6_addr;
+#ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
+	ip->ipv6_scope = sa6->sin6_scope_id;
+#endif
+	DEBUGP (("conaddr is: %s\n", print_address (ip)));
+	return true;
+      }
 #endif
-  if ((*sock = accept (msock, addr, &addrlen)) < 0)
-    return ACCEPTERR;
-  DEBUGP (("Created socket fd %d.\n", *sock));
-  return ACCEPTOK;
+    case AF_INET:
+      {
+	struct sockaddr_in *sa = (struct sockaddr_in *)&storage;
+	ip->data.d4 = sa->sin_addr;
+	DEBUGP (("conaddr is: %s\n", print_address (ip)));
+	return true;
+      }
+    default:
+      abort ();
+    }
 }
 
-/* Close SOCK, as well as the most recently remembered MSOCK, created
-   via bindport().  If SOCK is -1, close MSOCK only.  */
-void
-closeport (int sock)
+/* Return true if the error from the connect code can be considered
+   retryable.  Wget normally retries after errors, but the exception
+   are the "unsupported protocol" type errors (possible on IPv4/IPv6
+   dual family systems) and "connection refused".  */
+
+bool
+retryable_socket_connect_error (int err)
+{
+  /* Have to guard against some of these values not being defined.
+     Cannot use a switch statement because some of the values might be
+     equal.  */
+  if (false
+#ifdef EAFNOSUPPORT
+      || err == EAFNOSUPPORT
+#endif
+#ifdef EPFNOSUPPORT
+      || err == EPFNOSUPPORT
+#endif
+#ifdef ESOCKTNOSUPPORT		/* no, "sockt" is not a typo! */
+      || err == ESOCKTNOSUPPORT
+#endif
+#ifdef EPROTONOSUPPORT
+      || err == EPROTONOSUPPORT
+#endif
+#ifdef ENOPROTOOPT
+      || err == ENOPROTOOPT
+#endif
+      /* Apparently, older versions of Linux and BSD used EINVAL
+	 instead of EAFNOSUPPORT and such.  */
+      || err == EINVAL
+      )
+    return false;
+
+  if (!opt.retry_connrefused)
+    if (err == ECONNREFUSED
+#ifdef ENETUNREACH
+	|| err == ENETUNREACH	/* network is unreachable */
+#endif
+#ifdef EHOSTUNREACH
+	|| err == EHOSTUNREACH	/* host is unreachable */
+#endif
+	)
+      return false;
+
+  return true;
+}
+
+/* Wait for a single descriptor to become available, timing out after
+   MAXTIME seconds.  Returns 1 if FD is available, 0 for timeout and
+   -1 for error.  The argument WAIT_FOR can be a combination of
+   WAIT_FOR_READ and WAIT_FOR_WRITE.
+
+   This is a mere convenience wrapper around the select call, and
+   should be taken as such (for example, it doesn't implement Wget's
+   0-timeout-means-no-timeout semantics.)  */
+
+int
+select_fd (int fd, double maxtime, int wait_for)
 {
-  /*shutdown (sock, 2);*/
-  if (sock != -1)
-    CLOSE (sock);
-  if (msock != -1)
-    CLOSE (msock);
-  msock = -1;
+  fd_set fdset;
+  fd_set *rd = NULL, *wr = NULL;
+  struct timeval tmout;
+  int result;
+
+  FD_ZERO (&fdset);
+  FD_SET (fd, &fdset);
+  if (wait_for & WAIT_FOR_READ)
+    rd = &fdset;
+  if (wait_for & WAIT_FOR_WRITE)
+    wr = &fdset;
+
+  tmout.tv_sec = (long) maxtime;
+  tmout.tv_usec = 1000000 * (maxtime - (long) maxtime);
+
+  do
+    result = select (fd + 1, rd, wr, NULL, &tmout);
+  while (result < 0 && errno == EINTR);
+
+  return result;
 }
 
-/* Return the local IP address associated with the connection on FD.
-   It is returned in a static buffer.  */
-unsigned char *
-conaddr (int fd)
+/* Return true iff the connection to the remote site established
+   through SOCK is still open.
+
+   Specifically, this function returns true if SOCK is not ready for
+   reading.  This is because, when the connection closes, the socket
+   is ready for reading because EOF is about to be delivered.  A side
+   effect of this method is that sockets that have pending data are
+   considered non-open.  This is actually a good thing for callers of
+   this function, where such pending data can only be unwanted
+   leftover from a previous request.  */
+
+bool
+test_socket_open (int sock)
 {
-  static unsigned char res[4];
-  struct sockaddr_in mysrv;
-  struct sockaddr *myaddr;
-  size_t addrlen = sizeof (mysrv);
-
-  myaddr = (struct sockaddr *) (&mysrv);
-  if (getsockname (fd, myaddr, (int *)&addrlen) < 0)
-    return NULL;
-  memcpy (res, &mysrv.sin_addr, 4);
+  fd_set check_set;
+  struct timeval to;
+
+  /* Check if we still have a valid (non-EOF) connection.  From Andrew
+   * Maholski's code in the Unix Socket FAQ.  */
+
+  FD_ZERO (&check_set);
+  FD_SET (sock, &check_set);
+
+  /* Wait one microsecond */
+  to.tv_sec = 0;
+  to.tv_usec = 1;
+
+  if (select (sock + 1, &check_set, NULL, NULL, &to) == 0)
+    /* We got a timeout, it means we're still connected. */
+    return true;
+  else
+    /* Read now would not wait, it means we have either pending data
+       or EOF/error. */
+    return false;
+}
+
+/* Basic socket operations, mostly EINTR wrappers.  */
+
+#ifdef WINDOWS
+# define read(fd, buf, cnt) recv (fd, buf, cnt, 0)
+# define write(fd, buf, cnt) send (fd, buf, cnt, 0)
+# define close(fd) closesocket (fd)
+#endif
+
+#ifdef __BEOS__
+# define read(fd, buf, cnt) recv (fd, buf, cnt, 0)
+# define write(fd, buf, cnt) send (fd, buf, cnt, 0)
+#endif
+
+static int
+sock_read (int fd, char *buf, int bufsize)
+{
+  int res;
+  do
+    res = read (fd, buf, bufsize);
+  while (res == -1 && errno == EINTR);
   return res;
 }
 
-/* Read at most LEN bytes from FD, storing them to BUF.  This is
-   virtually the same as read(), but takes care of EINTR braindamage
-   and uses select() to timeout the stale connections (a connection is
-   stale if more than OPT.TIMEOUT time is spent in select() or
-   read()).  */
-int
-iread (int fd, char *buf, int len)
+static int
+sock_write (int fd, char *buf, int bufsize)
 {
   int res;
+  do
+    res = write (fd, buf, bufsize);
+  while (res == -1 && errno == EINTR);
+  return res;
+}
 
+static int
+sock_poll (int fd, double timeout, int wait_for)
+{
+  return select_fd (fd, timeout, wait_for);
+}
+
+static int
+sock_peek (int fd, char *buf, int bufsize)
+{
+  int res;
   do
+    res = recv (fd, buf, bufsize, MSG_PEEK);
+  while (res == -1 && errno == EINTR);
+  return res;
+}
+
+static void
+sock_close (int fd)
+{
+  close (fd);
+  DEBUGP (("Closed fd %d\n", fd));
+}
+#undef read
+#undef write
+#undef close
+
+/* Reading and writing from the network.  We build around the socket
+   (file descriptor) API, but support "extended" operations for things
+   that are not mere file descriptors under the hood, such as SSL
+   sockets.
+
+   That way the user code can call fd_read(fd, ...) and we'll run read
+   or SSL_read or whatever is necessary.  */
+
+static struct hash_table *transport_map;
+static unsigned int transport_map_modified_tick;
+
+struct transport_info {
+  struct transport_implementation *imp;
+  void *ctx;
+};
+
+/* Register the transport layer operations that will be used when
+   reading, writing, and polling FD.
+
+   This should be used for transport layers like SSL that piggyback on
+   sockets.  FD should otherwise be a real socket, on which you can
+   call getpeername, etc.  */
+
+void
+fd_register_transport (int fd, struct transport_implementation *imp, void *ctx)
+{
+  struct transport_info *info;
+
+  /* The file descriptor must be non-negative to be registered.
+     Negative values are ignored by fd_close(), and -1 cannot be used as
+     hash key.  */
+  assert (fd >= 0);
+
+  info = xnew (struct transport_info);
+  info->imp = imp;
+  info->ctx = ctx;
+  if (!transport_map)
+    transport_map = hash_table_new (0, NULL, NULL);
+  hash_table_put (transport_map, (void *)(intptr_t) fd, info);
+  ++transport_map_modified_tick;
+}
+
+/* Return context of the transport registered with
+   fd_register_transport.  This assumes fd_register_transport was
+   previously called on FD.  */
+
+void *
+fd_transport_context (int fd)
+{
+  struct transport_info *info = hash_table_get (transport_map, (void *)(intptr_t) fd);
+  return info->ctx;
+}
+
+/* When fd_read/fd_write are called multiple times in a loop, they should
+   remember the INFO pointer instead of fetching it every time.  It is
+   not enough to compare FD to LAST_FD because FD might have been
+   closed and reopened.  modified_tick ensures that changes to
+   transport_map will not be unnoticed.
+
+   This is a macro because we want the static storage variables to be
+   per-function.  */
+
+#define LAZY_RETRIEVE_INFO(info) do {					\
+  static struct transport_info *last_info;				\
+  static int last_fd = -1;						\
+  static unsigned int last_tick;					\
+  if (!transport_map)							\
+    info = NULL;							\
+  else if (last_fd == fd && last_tick == transport_map_modified_tick)	\
+    info = last_info;							\
+  else									\
+    {									\
+      info = hash_table_get (transport_map, (void *)(intptr_t) fd);	\
+      last_fd = fd;							\
+      last_info = info;							\
+      last_tick = transport_map_modified_tick;				\
+    }									\
+} while (0)
+
+static bool
+poll_internal (int fd, struct transport_info *info, int wf, double timeout)
+{
+  if (timeout == -1)
+    timeout = opt.read_timeout;
+  if (timeout)
     {
-#ifdef HAVE_SELECT
-      if (opt.timeout)
-	{
-	  do
-	    {
-	      res = select_fd (fd, opt.timeout, 0);
-	    }
-	  while (res == -1 && errno == EINTR);
-	  if (res <= 0)
-	    {
-	      /* Set errno to ETIMEDOUT on timeout.  */
-	      if (res == 0)
-		/* #### Potentially evil!  */
-		errno = ETIMEDOUT;
-	      return -1;
-	    }
-	}
-#endif
-      res = READ (fd, buf, len);
+      int test;
+      if (info && info->imp->poller)
+	test = info->imp->poller (fd, timeout, wf, info->ctx);
+      else
+	test = sock_poll (fd, timeout, wf);
+      if (test == 0)
+	errno = ETIMEDOUT;
+      if (test <= 0)
+	return false;
     }
-  while (res == -1 && errno == EINTR);
+  return true;
+}
 
-  return res;
+/* Read no more than BUFSIZE bytes of data from FD, storing them to
+   BUF.  If TIMEOUT is non-zero, the operation aborts if no data is
+   received after that many seconds.  If TIMEOUT is -1, the value of
+   opt.timeout is used for TIMEOUT.  */
+
+int
+fd_read (int fd, char *buf, int bufsize, double timeout)
+{
+  struct transport_info *info;
+  LAZY_RETRIEVE_INFO (info);
+  if (!poll_internal (fd, info, WAIT_FOR_READ, timeout))
+    return -1;
+  if (info && info->imp->reader)
+    return info->imp->reader (fd, buf, bufsize, info->ctx);
+  else
+    return sock_read (fd, buf, bufsize);
+}
+
+/* Like fd_read, except it provides a "preview" of the data that will
+   be read by subsequent calls to fd_read.  Specifically, it copies no
+   more than BUFSIZE bytes of the currently available data to BUF and
+   returns the number of bytes copied.  Return values and timeout
+   semantics are the same as those of fd_read.
+
+   CAVEAT: Do not assume that the first subsequent call to fd_read
+   will retrieve the same amount of data.  Reading can return more or
+   less data, depending on the TCP implementation and other
+   circumstances.  However, barring an error, it can be expected that
+   all the peeked data will eventually be read by fd_read.  */
+
+int
+fd_peek (int fd, char *buf, int bufsize, double timeout)
+{
+  struct transport_info *info;
+  LAZY_RETRIEVE_INFO (info);
+  if (!poll_internal (fd, info, WAIT_FOR_READ, timeout))
+    return -1;
+  if (info && info->imp->peeker)
+    return info->imp->peeker (fd, buf, bufsize, info->ctx);
+  else
+    return sock_peek (fd, buf, bufsize);
 }
 
-/* Write LEN bytes from BUF to FD.  This is similar to iread(), but
-   doesn't bother with select().  Unlike iread(), it makes sure that
-   all of BUF is actually written to FD, so callers needn't bother
-   with checking that the return value equals to LEN.  Instead, you
-   should simply check for -1.  */
+/* Write the entire contents of BUF to FD.  If TIMEOUT is non-zero,
+   the operation aborts if no data is received after that many
+   seconds.  If TIMEOUT is -1, the value of opt.timeout is used for
+   TIMEOUT.  */
+
 int
-iwrite (int fd, char *buf, int len)
+fd_write (int fd, char *buf, int bufsize, double timeout)
 {
-  int res = 0;
+  int res;
+  struct transport_info *info;
+  LAZY_RETRIEVE_INFO (info);
 
-  /* `write' may write less than LEN bytes, thus the outward loop
-     keeps trying it until all was written, or an error occurred.  The
-     inner loop is reserved for the usual EINTR f*kage, and the
-     innermost loop deals with the same during select().  */
-  while (len > 0)
+  /* `write' may write less than LEN bytes, thus the loop keeps trying
+     it until all was written, or an error occurred.  */
+  res = 0;
+  while (bufsize > 0)
     {
-      do
-	{
-#ifdef HAVE_SELECT
-	  if (opt.timeout)
-	    {
-	      do
-		{
-		  res = select_fd (fd, opt.timeout, 1);
-		}
-	      while (res == -1 && errno == EINTR);
-	      if (res <= 0)
-		{
-		  /* Set errno to ETIMEDOUT on timeout.  */
-		  if (res == 0)
-		    /* #### Potentially evil!  */
-		    errno = ETIMEDOUT;
-		  return -1;
-		}
-	    }
-#endif
-	  res = WRITE (fd, buf, len);
-	}
-      while (res == -1 && errno == EINTR);
+      if (!poll_internal (fd, info, WAIT_FOR_WRITE, timeout))
+	return -1;
+      if (info && info->imp->writer)
+	res = info->imp->writer (fd, buf, bufsize, info->ctx);
+      else
+	res = sock_write (fd, buf, bufsize);
       if (res <= 0)
 	break;
       buf += res;
-      len -= res;
+      bufsize -= res;
     }
   return res;
 }
+
+/* Report the most recent error(s) on FD.  This should only be called
+   after fd_* functions, such as fd_read and fd_write, and only if
+   they return a negative result.  For errors coming from other calls
+   such as setsockopt or fopen, strerror should continue to be
+   used.
+
+   If the transport doesn't support error messages or doesn't supply
+   one, strerror(errno) is returned.  The returned error message
+   should not be used after fd_close has been called.  */
+
+const char *
+fd_errstr (int fd)
+{
+  /* Don't bother with LAZY_RETRIEVE_INFO, as this will only be called
+     in case of error, never in a tight loop.  */
+  struct transport_info *info = NULL;
+  if (transport_map)
+    info = hash_table_get (transport_map, (void *)(intptr_t) fd);
+
+  if (info && info->imp->errstr)
+    {
+      const char *err = info->imp->errstr (fd, info->ctx);
+      if (err)
+	return err;
+      /* else, fall through and print the system error. */
+    }
+  return strerror (errno);
+}
+
+/* Close the file descriptor FD.  */
+
+void
+fd_close (int fd)
+{
+  struct transport_info *info;
+  if (fd < 0)
+    return;
+
+  /* Don't use LAZY_RETRIEVE_INFO because fd_close() is only called once
+     per socket, so that particular optimization wouldn't work.  */
+  info = NULL;
+  if (transport_map)
+    info = hash_table_get (transport_map, (void *)(intptr_t) fd);
+
+  if (info && info->imp->closer)
+    info->imp->closer (fd, info->ctx);
+  else
+    sock_close (fd);
+
+  if (info)
+    {
+      hash_table_remove (transport_map, (void *)(intptr_t) fd);
+      xfree (info);
+      ++transport_map_modified_tick;
+    }
+}