Added <ifaddrs.h> interface with functions `getifaddrs', `freeifaddrs'.

	This implementation supports only IPv4.
	* inet/ifaddrs.h: New file.
	* sysdeps/generic/ifaddrs.c: New file.
	* sysdeps/gnu/ifaddrs.c: New file.
	* inet/test-ifaddrs.c: New file.
	* inet/Makefile (routines): Add ifaddrs.
	(headers): Add ifaddrs.h here.
	(tests): Add test-ifaddrs.
	* inet/Versions (GLIBC_2.3): New set, add getifaddrs and freeifaddrs.

	* resolv/res_hconf.c (_res_hconf_reorder_addrs): Use an explicit
	socket call to get an AF_INET socket, instead of using __opensock.
	The SIOCGIFNETMASK ioctl will work only with a PF_INET socket.

	* sysdeps/generic/ifreq.h (__ifreq): Take third argument SOCKFD,
	if not -1 use it instead of calling __opensock.
	* sysdeps/unix/sysv/linux/ifreq.h (__ifreq): Likewise.
	* sysdeps/mach/hurd/ifreq.h (__ifreq): Take new argument and ignore it.
	* resolv/res_hconf.c (_res_hconf_reorder_addrs): Pass new argument.

	* sysdeps/mach/hurd/ifreq.h: New file.
	* sysdeps/generic/ifreq.h (__if_freereq): Take second argument NUM_IFS.
	* sysdeps/unix/sysv/linux/ifreq.h (__if_freereq): Likewise.
	* resolv/res_hconf.c (_res_hconf_reorder_addrs): Update caller.

1 files changed, 147 insertions, 0 deletions

diff --git a/sysdeps/gnu/ifaddrs.c b/sysdeps/gnu/ifaddrs.c
new file mode 100644
index 0000000000..e0a5b424f0
--- /dev/null
+++ b/sysdeps/gnu/ifaddrs.c
@@ -0,0 +1,147 @@
+/* getifaddrs -- get names and addresses of all network interfaces
+   Copyright (C) 2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <ifaddrs.h>
+#include <net/if.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <netinet/in.h>
+
+#include "ifreq.h"
+
+/* Create a linked list of `struct ifaddrs' structures, one for each
+   network interface on the host machine.  If successful, store the
+   list in *IFAP and return 0.  On errors, return -1 and set `errno'.  */
+int
+getifaddrs (struct ifaddrs **ifap)
+{
+  /* This implementation handles only IPv4 interfaces.
+     The various ioctls below will only work on an AF_INET socket.
+     Some different mechanism entirely must be used for IPv6.  */
+  int fd = __socket (AF_INET, SOCK_DGRAM, 0);
+  struct ifreq *ifreqs;
+  int nifs, i;
+
+  if (fd < 0)
+    return -1;
+
+  __ifreq (&ifreqs, &nifs, fd);
+  if (ifreqs == NULL)		/* XXX doesn't distinguish error vs none */
+    {
+      __close (fd);
+      return -1;
+    }
+
+  /* Now we have the list of interfaces and each one's address.
+     Put it into the expected format and fill in the remaining details.  */
+  if (nifs == 0)
+    *ifap = NULL;
+  else
+    {
+      struct
+      {
+	struct ifaddrs ia;
+	struct sockaddr addr, netmask, broadaddr;
+	char name[IF_NAMESIZE];
+      } *storage;
+
+      storage = malloc (nifs * sizeof storage[0]);
+      if (storage == NULL)
+	{
+	  __close (fd);
+	  __if_freereq (ifreqs, nifs);
+	  return -1;
+	}
+
+      i = 0;
+      do
+	{
+	  struct ifreq *const ifr = &ifreqs[i];
+
+	  /* Fill in all pointers to the storage we've already allocated.  */
+	  storage[i].ia.ifa_next = &storage[i + 1].ia;
+	  storage[i].ia.ifa_addr = &storage[i].addr;
+	  storage[i].ia.ifa_netmask = &storage[i].netmask;
+	  storage[i].ia.ifa_broadaddr = &storage[i].broadaddr; /* & dstaddr */
+
+	  /* Now copy the information we already have from SIOCGIFCONF.  */
+	  storage[i].ia.ifa_name = strncpy (storage[i].name, ifr->ifr_name,
+					    sizeof storage[i].name);
+	  storage[i].addr = ifr->ifr_addr;
+
+	  /* The SIOCGIFCONF call filled in only the name and address.
+	     Now we must also ask for the other information we need.  */
+
+	  if (__ioctl (fd, SIOCGIFFLAGS, ifr) < 0)
+	    break;
+	  storage[i].ia.ifa_flags = ifr->ifr_flags;
+
+	  ifr->ifr_addr = storage[i].addr;
+	  if (__ioctl (fd, SIOCGIFNETMASK, ifr) < 0)
+	    break;
+	  storage[i].netmask = ifr->ifr_netmask;
+
+	  if (ifr->ifr_flags & IFF_BROADCAST)
+	    {
+	      ifr->ifr_addr = storage[i].addr;
+	      if (__ioctl (fd, SIOCGIFBRDADDR, ifr) < 0)
+		break;
+	      storage[i].broadaddr = ifr->ifr_broadaddr;
+	    }
+	  else if (ifr->ifr_flags & IFF_POINTOPOINT)
+	    {
+	      ifr->ifr_addr = storage[i].addr;
+	      if (__ioctl (fd, SIOCGIFDSTADDR, ifr) < 0)
+		break;
+	      storage[i].broadaddr = ifr->ifr_dstaddr;
+	    }
+	  else
+	    /* Just 'cause.  */
+	    memset (&storage[i].broadaddr, 0, sizeof storage[i].broadaddr);
+
+	  storage[i].ia.ifa_data = NULL; /* Nothing here for now.  */
+
+	} while (++i < nifs);
+      if (i < nifs)		/* Broke out early on error.  */
+	{
+	  __close (fd);
+	  free (storage);
+	  __if_freereq (ifreqs, nifs);
+	  return -1;
+	}
+      storage[i - 1].ia.ifa_next = NULL;
+
+      *ifap = &storage[0].ia;
+
+      __close (fd);
+      __if_freereq (ifreqs, nifs);
+    }
+
+  return 0;
+}
+
+void
+freeifaddrs (struct ifaddrs *ifa)
+{
+  free (ifa);
+}