* autoload.cc (WSAIoctl): Define.

	(SendARP): Define.
	* cygwin.din: Export if_freenameindex, if_indextoname, if_nameindex and
	if_nametoindex.
	* fhandler_procnet.cc: Drop including wchar.h.  Drop definitions of
	GAA_FLAG_INCLUDE_ALL_INTERFACES, IP_ADAPTER_UNICAST_ADDRESS_VISTA.
	(fhandler_procnet::exists): Check for has_gaa_prefixes.  Call
	get_adapters_addresses here.
	(fhandler_procnet::readdir): Ditto.
	(prefix): Move to net.cc.
	(fhandler_procnet::fill_filebuf): Call get_adapters_addresses here.
	Simplify allocation.  Use AdapterName rather than FriendlyName as
	interface name.  Use IfIndex if available, Ipv6IfIndex otherwise.
	(in6_are_prefix_equal): Move to net.cc.
	* fhandler_socket.cc: Define old SIOCGxxx values.
	(CONV_OLD_TO_NEW_SIO): Convert old SIOCGxxx value to new one.
	(struct __old_ifreq): Define old struct ifreq.
	(fhandler_socket::ioctl): Handle old SIOCGxxx values.  Handle new
	SIOCGIFFRNDLYNAM command.  Simplify copying ifreq data to user space.
	Call get_ifconf with additional SOCKET parameter.
	* net.cc (IP_ADAPTER_UNICAST_ADDRESS_LH): Define.
	(IP_ADAPTER_ADDRESSES_LH): Define.
	(SIO_GET_INTERFACE_LIST): Define.
	(sockaddr_in6_old): Define.
	(sockaddr_gen): Define.
	(INTERFACE_INFO): Define.
	(IN_LOOPBACK): Define.
	(in_are_prefix_equal): New static function.
	(ip_addr_prefix): New function, replaces prefix function, add AF_INET
	handling.
	(GAA_FLAG_INCLUDE_ALL_INTERFACES): Define.
	(get_adapters_addresses): New function.
	(WS_IFF_xxx): Define Winsock interface flag values.
	(convert_ifr_flags): New function to convert Winsock interface flag
	values to Cygwin interface flag values.
	(get_xp_ifconf): New get_ifconf implementation for XP SP1 and above.
	(get_2k_ifconf): Fix interface index.  Fix formatting.
	(get_nt_ifconf): Fix formatting.
	(get_95_ifconf): Ditto.
	(get_ifconf): Take additional SOCKET parameter.  Call get_xp_ifconf
	on XP SP1 and above.
	(if_nametoindex): New function.
	(if_indextoname): New function.
	(if_nameindex): New function.
	(if_freenameindex): New function.
	(in6_are_prefix_equal): Moved here from fhandler_procnet.cc.
	* wincap.cc (wincap_xp): Define has_gaa_prefixes as true by default.
	(wincapc::init): Assume has_osversioninfoex by default.  Call
	GetVersionEx with OSVERSIONINFOEX first.  Call with OSVERSIONINFO only
	if that fails.  Simplify NT4 case and try to avoid strcmp.  Check XP
	Service Pack using version.wServicePackMajor to avoid strcmp.
	* include/asm/socket.h (SIOCGIFFRNDLYNAM): Define.
	* include/cygwin/if.h: Fix formatting.
	(IFF_POINTTOPOINT): Define.
	(IFF_NOARP): Define.
	(IFF_LOWER_UP): Define.
	(IFF_DORMANT): Define.
	(struct if_nameindex): Define.
	(IFRF_FRIENDLYNAMESIZ): Define.
	(struct ifreq_frndlyname): Define.
	(IFNAMSIZ): Redefine as 44.
	(IF_NAMESIZE): Define.
	(struct ifreq): Redefine ifru_flags as int.  Define ifru_data.  Pad size
	to sizeof sockaddr_in6 for further extensions.
	(ifr_data): Define.
	(ifr_frndlyname): Define.
	(if_nametoindex): Declare.
	(if_indextoname): Declare.
	(if_nameindex): Declare.
	(if_freenameindex): Declare.
	* include/cygwin/version.h: Bump API minor number.
	(CYGWIN_VERSION_CHECK_FOR_OLD_IFREQ): Define check for old vs. new
	ifreq structure.

1 files changed, 497 insertions, 6 deletions

diff --git a/winsup/cygwin/net.cc b/winsup/cygwin/net.cc
index 13a1ee9df..c6cf34b60 100644
--- a/winsup/cygwin/net.cc
+++ b/winsup/cygwin/net.cc
@@ -1125,6 +1125,315 @@ getdomainname (char *domain, size_t len)
 
 /* Fill out an ifconf struct. */
 
+/* Vista/Longhorn: unicast address has additional OnLinkPrefixLength member. */
+typedef struct _IP_ADAPTER_UNICAST_ADDRESS_LH {
+    _ANONYMOUS_UNION union {
+        ULONGLONG Alignment;
+        _ANONYMOUS_UNION struct {
+            ULONG Length;
+            DWORD Flags;
+        } DUMMYSTRUCTNAME;
+    } DUMMYUNIONNAME;
+    struct _IP_ADAPTER_UNICAST_ADDRESS_VISTA *Next;
+    SOCKET_ADDRESS Address;
+    IP_PREFIX_ORIGIN PrefixOrigin;
+    IP_SUFFIX_ORIGIN SuffixOrigin;
+    IP_DAD_STATE DadState;
+    ULONG ValidLifetime;
+    ULONG PreferredLifetime;
+    ULONG LeaseLifetime;
+    unsigned char OnLinkPrefixLength;
+} IP_ADAPTER_UNICAST_ADDRESS_LH, *PIP_ADAPTER_UNICAST_ADDRESS_LH;
+
+/* Vista/Longhorn: IP_ADAPTER_ADDRESSES has a lot more info.  We pick only
+   what we need for now. */
+typedef struct _IP_ADAPTER_ADDRESSES_LH {
+  _ANONYMOUS_UNION union {
+    ULONGLONG Alignment;
+    _ANONYMOUS_STRUCT struct {
+      ULONG Length;
+      DWORD IfIndex;
+    } DUMMYSTRUCTNAME;
+  } DUMMYUNIONNAME;
+  struct _IP_ADAPTER_ADDRESSES* Next;
+  PCHAR AdapterName;
+  PIP_ADAPTER_UNICAST_ADDRESS FirstUnicastAddress;
+  PIP_ADAPTER_ANYCAST_ADDRESS FirstAnycastAddress;
+  PIP_ADAPTER_MULTICAST_ADDRESS FirstMulticastAddress;
+  PIP_ADAPTER_DNS_SERVER_ADDRESS FirstDnsServerAddress;
+  PWCHAR DnsSuffix;
+  PWCHAR Description;
+  PWCHAR FriendlyName;
+  BYTE PhysicalAddress[MAX_ADAPTER_ADDRESS_LENGTH];
+  DWORD PhysicalAddressLength;
+  DWORD Flags;
+  DWORD Mtu;
+  DWORD IfType;
+  IF_OPER_STATUS OperStatus;
+  DWORD Ipv6IfIndex;
+  DWORD ZoneIndices[16];
+  PIP_ADAPTER_PREFIX FirstPrefix;
+
+  ULONG64 TransmitLinkSpeed;
+  ULONG64 ReceiveLinkSpeed;
+  PVOID FirstWinsServerAddress;
+  PVOID FirstGatewayAddress;
+  ULONG Ipv4Metric;
+  ULONG Ipv6Metric;
+} IP_ADAPTER_ADDRESSES_LH,*PIP_ADAPTER_ADDRESSES_LH;
+
+/* We can't include ws2tcpip.h. */
+
+#define SIO_GET_INTERFACE_LIST  _IOR('t', 127, u_long)
+
+struct sockaddr_in6_old {
+  short   sin6_family;
+  u_short sin6_port;
+  u_long  sin6_flowinfo;
+  struct in6_addr sin6_addr;
+};
+
+typedef union sockaddr_gen{
+  struct sockaddr         Address;
+  struct sockaddr_in      AddressIn;
+  struct sockaddr_in6_old AddressIn6;
+} sockaddr_gen;
+
+typedef struct _INTERFACE_INFO {
+  u_long          iiFlags;
+  sockaddr_gen    iiAddress;
+  sockaddr_gen    iiBroadcastAddress;
+  sockaddr_gen    iiNetmask;
+} INTERFACE_INFO, *LPINTERFACE_INFO;
+
+#ifndef IN_LOOPBACK
+#define IN_LOOPBACK(a)          ((((long int) (a)) & 0xff000000) == 0x7f000000)
+#endif
+
+static int in6_are_prefix_equal (struct in6_addr *, struct in6_addr *, int);
+
+static int in_are_prefix_equal (struct in_addr *p1, struct in_addr *p2, int len)
+{
+  if (0 > len || len > 32)
+    return 0;
+  uint32_t pfxmask = 0xffffffff << (32 - len);
+  return (p1->s_addr & pfxmask) == (p2->s_addr & pfxmask);
+}
+
+extern "C" int
+ip_addr_prefix (PIP_ADAPTER_UNICAST_ADDRESS pua, PIP_ADAPTER_PREFIX pap)
+{
+  if (wincap.has_gaa_on_link_prefix ())
+    return (int) ((PIP_ADAPTER_UNICAST_ADDRESS_LH) pua)->OnLinkPrefixLength;
+  switch (pua->Address.lpSockaddr->sa_family)
+    {
+    case AF_INET:
+      /* Prior to Vista, the loopback prefix is not available. */
+      if (IN_LOOPBACK (((struct sockaddr_in *)
+			pua->Address.lpSockaddr)->sin_addr.s_addr))
+        return 8;
+      for ( ; pap; pap = pap->Next)
+	if (in_are_prefix_equal (
+	      &((struct sockaddr_in *) pua->Address.lpSockaddr)->sin_addr,
+	      &((struct sockaddr_in *) pap->Address.lpSockaddr)->sin_addr,
+	      pap->PrefixLength))
+	  return pap->PrefixLength;
+      break;
+    case AF_INET6:
+      /* Prior to Vista, the loopback prefix is not available. */
+      if (IN6_IS_ADDR_LOOPBACK (&((struct sockaddr_in6 *)
+				  pua->Address.lpSockaddr)->sin6_addr))
+	return 128;
+      for ( ; pap; pap = pap->Next)
+	if (in6_are_prefix_equal (
+	      &((struct sockaddr_in6 *) pua->Address.lpSockaddr)->sin6_addr,
+	      &((struct sockaddr_in6 *) pap->Address.lpSockaddr)->sin6_addr,
+	      pap->PrefixLength))
+	  return pap->PrefixLength;
+      break;
+    default:
+      break;
+    }
+  return 0;
+}
+
+#ifndef GAA_FLAG_INCLUDE_ALL_INTERFACES
+#define GAA_FLAG_INCLUDE_ALL_INTERFACES 0x0100
+#endif
+
+bool
+get_adapters_addresses (PIP_ADAPTER_ADDRESSES *pa_ret, ULONG family)
+{
+  DWORD ret, size = 0;
+  PIP_ADAPTER_ADDRESSES pa0 = NULL;
+
+  if (!pa_ret)
+    return ERROR_BUFFER_OVERFLOW
+	   == GetAdaptersAddresses (family, GAA_FLAG_INCLUDE_PREFIX
+					    | GAA_FLAG_INCLUDE_ALL_INTERFACES,
+				    NULL, NULL, &size);
+  do
+    {
+      ret = GetAdaptersAddresses (family, GAA_FLAG_INCLUDE_PREFIX
+					  | GAA_FLAG_INCLUDE_ALL_INTERFACES,
+				  NULL, pa0, &size);
+      if (ret == ERROR_BUFFER_OVERFLOW
+	  && !(pa0 = (PIP_ADAPTER_ADDRESSES) realloc (pa0, size)))
+	break;
+    }
+  while (ret == ERROR_BUFFER_OVERFLOW);
+  if (ret != ERROR_SUCCESS)
+    {
+      if (pa0)
+        free (pa0);
+      *pa_ret = NULL;
+      return false;
+    }
+  *pa_ret = pa0;
+  return true;
+}
+
+#define WS_IFF_UP	     1
+#define WS_IFF_BROADCAST     2
+#define WS_IFF_LOOPBACK	     4
+#define WS_IFF_POINTTOPOINT  8
+#define WS_IFF_MULTICAST    16
+
+static inline short
+convert_ifr_flags (u_long ws_flags)
+{
+  return (ws_flags & (WS_IFF_UP | WS_IFF_BROADCAST))
+  	 | ((ws_flags & (WS_IFF_LOOPBACK | WS_IFF_POINTTOPOINT)) << 1)
+	 | ((ws_flags & WS_IFF_MULTICAST) << 8);
+}
+
+/*
+ * IFCONF XP SP1 and above.
+ * Use IP Helpper function GetAdaptersAddresses.
+ */
+
+static void
+get_xp_ifconf (SOCKET s, struct ifconf *ifc, int what)
+{
+  PIP_ADAPTER_ADDRESSES pa0 = NULL, pap;
+  PIP_ADAPTER_UNICAST_ADDRESS pua;
+  LPINTERFACE_INFO iie;
+  int cnt = 0;
+  DWORD size = 0;
+
+  if (!get_adapters_addresses (&pa0, AF_INET))
+    goto done;
+  
+  for (pap = pa0; pap; pap = pap->Next)
+    for (pua = pap->FirstUnicastAddress; pua; pua = pua->Next)
+      ++cnt;
+  /* If the size matches exactly the number of interfaces, WSAIoctl fails
+     with WSAError set to WSAEFAULT, for no apparent reason.  So we allocate
+     space for one more INTERFACE_INFO structure here. */
+  iie = (LPINTERFACE_INFO) alloca ((cnt + 1) * sizeof (INTERFACE_INFO));
+  if (WSAIoctl (s, SIO_GET_INTERFACE_LIST, NULL, 0, iie,
+  		(cnt + 1) * sizeof (INTERFACE_INFO), &size, NULL, NULL))
+    {
+      set_winsock_errno ();
+      cnt = 0;
+      goto done;
+    }
+      
+  struct ifreq *ifr = ifc->ifc_req;
+  for (pap = pa0; pap; pap = pap->Next)
+    {
+      int idx = 0;
+      for (pua = pap->FirstUnicastAddress; pua; pua = pua->Next)
+        {
+	  int iinf_idx;
+	  for (iinf_idx = 0; iinf_idx < cnt; ++iinf_idx)
+	    if (iie[iinf_idx].iiAddress.AddressIn.sin_addr.s_addr
+		==  ((sockaddr_in *) pua->Address.lpSockaddr)->sin_addr.s_addr)
+	      break;
+	  if (iinf_idx >= cnt)
+	    continue;
+	  if (!idx)
+	    strcpy (ifr->ifr_name, pap->AdapterName);
+	  else
+	    __small_sprintf (ifr->ifr_name, "%s:%u", pap->AdapterName, idx);
+	  ++idx;
+	  switch (what)
+	    {
+	    case SIOCGIFFLAGS:
+	      {
+		ifr->ifr_flags = convert_ifr_flags (iie[iinf_idx].iiFlags);
+		if (pap->OperStatus == IfOperStatusUp
+		    || pap->OperStatus == IfOperStatusUnknown)
+		  ifr->ifr_flags |= IFF_RUNNING;
+		if (pap->OperStatus != IfOperStatusLowerLayerDown)
+		  ifr->ifr_flags |= IFF_LOWER_UP;
+		if (pap->OperStatus == IfOperStatusDormant)
+		  ifr->ifr_flags |= IFF_DORMANT;
+		ULONG hwaddr[2], hwlen = 6;
+		if (SendARP (iie[iinf_idx].iiAddress.AddressIn.sin_addr.s_addr,
+			     0, hwaddr, &hwlen))
+		  ifr->ifr_flags |= IFF_NOARP;
+	      }
+	      break;
+	    case SIOCGIFCONF:
+	    case SIOCGIFADDR:
+	      memcpy (&ifr->ifr_addr,
+		      &iie[iinf_idx].iiAddress.AddressIn,
+		      sizeof (struct sockaddr_in));
+	      break;
+	    case SIOCGIFBRDADDR:
+	      memcpy (&ifr->ifr_broadaddr,
+		      &iie[iinf_idx].iiBroadcastAddress.AddressIn,
+		      sizeof (struct sockaddr_in));
+	      break;
+	    case SIOCGIFNETMASK:
+	      memcpy (&ifr->ifr_netmask,
+		      &iie[iinf_idx].iiNetmask.AddressIn,
+		      sizeof (struct sockaddr_in));
+	      break;
+	    case SIOCGIFHWADDR:
+	      for (UINT i = 0; i < IFHWADDRLEN; ++i)
+		if (i >= pap->PhysicalAddressLength)
+		  ifr->ifr_hwaddr.sa_data[i] = '\0';
+		else
+		  ifr->ifr_hwaddr.sa_data[i] = pap->PhysicalAddress[i];
+	      ifr->ifr_hwaddr.sa_family = AF_INET;
+	      break;
+	    case SIOCGIFMETRIC:
+	      if (wincap.has_gaa_on_link_prefix ())
+	        ifr->ifr_metric = ((PIP_ADAPTER_ADDRESSES_LH) pap)->Ipv4Metric;
+	      else
+		ifr->ifr_metric = 1;
+	      break;
+	    case SIOCGIFMTU:
+	      ifr->ifr_mtu = pap->Mtu;
+	      break;
+	    case SIOCGIFINDEX:
+	      ifr->ifr_ifindex = pap->IfIndex;
+	      break;
+	    case SIOCGIFFRNDLYNAM:
+	      {
+		struct ifreq_frndlyname *iff = (struct ifreq_frndlyname *)
+					       ifr->ifr_frndlyname;
+		iff->ifrf_len = sys_wcstombs (iff->ifrf_friendlyname,
+					      IFRF_FRIENDLYNAMESIZ,
+					      pap->FriendlyName);
+	      }
+	      break;
+	    }
+	  if ((caddr_t) ++ifr >
+	      ifc->ifc_buf + ifc->ifc_len - sizeof (struct ifreq))
+	    goto done;
+	}
+    }
+
+done:
+  if (pa0)
+    free (pa0);
+  /* Set the correct length */
+  ifc->ifc_len = cnt * sizeof (struct ifreq);
+}
+
 /*
  * IFCONF 98/ME, NTSP4, W2K:
  * Use IP Helper Library
@@ -1239,7 +1548,7 @@ get_2k_ifconf (struct ifconf *ifc, int what)
 		__small_sprintf (ifr->ifr_name, "%s%u", name, ifEntry->classId);
 	      else
 		__small_sprintf (ifr->ifr_name, "%s%u:%u", name,
-				 ifEntry->classId, ifEntry->enumerated - 1);
+				 ifEntry->classId, ifEntry->enumerated);
 	      ifEntry->enumerated++;
 	    }
 
@@ -1304,7 +1613,7 @@ get_2k_ifconf (struct ifconf *ifc, int what)
 		break;
 	    }
 	  ++cnt;
-	  if ((caddr_t)++ ifr >
+	  if ((caddr_t) ++ifr >
 	      ifc->ifc_buf + ifc->ifc_len - sizeof (struct ifreq))
 	    goto done;
 	}
@@ -1396,7 +1705,7 @@ get_nt_ifconf (struct ifconf *ifc, int what)
 		   *ip && *np;
 		   ip += strlen (ip) + 1, np += strlen (np) + 1)
 		{
-		  if ((caddr_t)++ ifr > ifc->ifc_buf
+		  if ((caddr_t) ++ifr > ifc->ifc_buf
 		      + ifc->ifc_len - sizeof (struct ifreq))
 		    break;
 
@@ -1606,7 +1915,7 @@ get_95_ifconf (struct ifconf *ifc, int what)
 			      NULL, (unsigned char *) np,
 			      (size = sizeof np, &size)) == ERROR_SUCCESS)
 	{
-	  if ((caddr_t)++ ifr > ifc->ifc_buf
+	  if ((caddr_t) ++ifr > ifc->ifc_buf
 	      + ifc->ifc_len - sizeof (struct ifreq))
 	    goto out;
 
@@ -1697,7 +2006,7 @@ out:
 }
 
 int
-get_ifconf (struct ifconf *ifc, int what)
+get_ifconf (SOCKET s, struct ifconf *ifc, int what)
 {
   unsigned long lip, lnp;
   struct sockaddr_in *sa;
@@ -1768,7 +2077,9 @@ get_ifconf (struct ifconf *ifc, int what)
 	}
     }
 
-  if (wincap.has_ip_helper_lib ())
+  if (wincap.has_gaa_prefixes () && !CYGWIN_VERSION_CHECK_FOR_OLD_IFREQ)
+    get_xp_ifconf (s, ifc, what);
+  else if (wincap.has_ip_helper_lib ())
     get_2k_ifconf (ifc, what);
   else if (wincap.is_winnt ())
     get_nt_ifconf (ifc, what);
@@ -1777,6 +2088,102 @@ get_ifconf (struct ifconf *ifc, int what)
   return 0;
 }
 
+extern "C" unsigned
+if_nametoindex (const char *name)
+{
+  PIP_ADAPTER_ADDRESSES pap = NULL;
+
+  myfault efault;
+  if (efault.faulted (EFAULT))
+    return 0;
+
+  if (wincap.has_gaa_prefixes ()
+      && get_adapters_addresses (&pap, AF_UNSPEC))
+    {
+      char lname[IF_NAMESIZE], *c;
+
+      lname[0] = '\0';
+      strncat (lname, name, IF_NAMESIZE - 1);
+      if (lname[0] == '{' && (c = strchr (lname, ':')))
+	*c = '\0';
+      for (; pap; pap = pap->Next)
+	if (strcasematch (lname, pap->AdapterName))
+	  return pap->IfIndex;
+    }
+  return 0;
+}
+
+extern "C" char *
+if_indextoname (unsigned ifindex, char *ifname)
+{
+  PIP_ADAPTER_ADDRESSES pap = NULL;
+
+  myfault efault;
+  if (efault.faulted (EFAULT))
+    return NULL;
+
+  if (wincap.has_gaa_prefixes ()
+      && get_adapters_addresses (&pap, AF_UNSPEC))
+    {
+      for (; pap; pap = pap->Next)
+        if (ifindex == pap->IfIndex)
+	  {
+	    strcpy (ifname, pap->AdapterName);
+	    return ifname;
+	  }
+    }
+  set_errno (ENXIO);
+  return NULL;
+}
+
+extern "C" struct if_nameindex *
+if_nameindex (void)
+{
+  PIP_ADAPTER_ADDRESSES pa0 = NULL, pap;
+  struct if_nameindex *iflist = NULL;
+  char (*ifnamelist)[IF_NAMESIZE];
+
+  myfault efault;
+  if (efault.faulted (EFAULT))
+    return NULL;
+
+  if (wincap.has_gaa_prefixes ()
+      && get_adapters_addresses (&pa0, AF_UNSPEC))
+    {
+      int cnt = 0;
+      for (pap = pa0; pap; pap = pap->Next)
+        ++cnt;
+      iflist = (struct if_nameindex *)
+	       malloc ((cnt + 1) * sizeof (struct if_nameindex)
+		       + cnt * IF_NAMESIZE);
+      if (!iflist)
+        {
+	  set_errno (ENOBUFS);
+	  return NULL;
+	}
+      ifnamelist = (char (*)[IF_NAMESIZE]) (iflist + cnt + 1);
+      for (pap = pa0, cnt = 0; pap; pap = pap->Next, ++cnt)
+        {
+	  iflist[cnt].if_index = pap->IfIndex ?: pap->Ipv6IfIndex;
+	  strcpy (iflist[cnt].if_name = ifnamelist[cnt], pap->AdapterName);
+	}
+      iflist[cnt].if_index = 0;
+      iflist[cnt].if_name = NULL;
+      return iflist;
+    }
+  set_errno (ENXIO);
+  return NULL;
+}
+
+extern "C" void
+if_freenameindex (struct if_nameindex *ptr)
+{
+  myfault efault;
+  if (efault.faulted (EFAULT))
+    return;
+  free (ptr);
+}
+
 #define PORT_LOW	(IPPORT_EFSSERVER + 1)
 #define PORT_HIGH	(IPPORT_RESERVED - 1)
 #define NUM_PORTS	(PORT_HIGH - PORT_LOW + 1)
@@ -3493,3 +3900,87 @@ cygwin_getnameinfo (const struct sockaddr *sa, socklen_t salen,
   return ipv4_getnameinfo (sa, salen, host, hostlen, serv, servlen, flags);
 }
 
+/* The below function has been taken from OpenBSD's src/sys/netinet6/in6.c. */
+
+/*
+ * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * Copyright (c) 1982, 1986, 1991, 1993
+ *      The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *      @(#)in.c        8.2 (Berkeley) 11/15/93
+ */
+
+static int
+in6_are_prefix_equal (struct in6_addr *p1, struct in6_addr *p2, int len)
+{
+  int bytelen, bitlen;
+
+  /* sanity check */
+  if (0 > len || len > 128)
+    return 0;
+  
+  bytelen = len / 8;
+  bitlen = len % 8;
+
+  if (memcmp (&p1->s6_addr, &p2->s6_addr, bytelen))
+    return 0;
+  /* len == 128 is ok because bitlen == 0 then */
+  if (bitlen != 0 &&
+      p1->s6_addr[bytelen] >> (8 - bitlen) !=
+      p2->s6_addr[bytelen] >> (8 - bitlen))
+    return 0;
+
+  return 1;
+}