Cause runtime probing of v6 addresses to fail, even if we can actually

make v6 sockets, but we do not have struct in6_pktinfo.

Add a check in configure.in for struct in6_pktinfo.

Use the result of that check to define (if needed) in6_pktinfo in net.h.

This change makes us build on platforms that have SOME ipv6 structures
(like in6_addr, etc) but not enough to be useful to us.

Note:  Before making an ipv6 socket the code should verify that ipv6
sockets can be made using isc_net_probeipv6().  It should also
check for v4 sockets using isc_net_probeipv4() to be consistant.

configure.in

@@ -13,7 +13,7 @@ dnl PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 dnl ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 dnl SOFTWARE.
 
-AC_REVISION($Revision: 1.124 $)
+AC_REVISION($Revision: 1.125 $)
 
 AC_PREREQ(2.13)
 
@@ -616,6 +616,8 @@ case "$enable_ipv6" in
 		;;
 esac
 
+echo "======= $found_ipv6"
+
 case "$found_ipv6" in
 	yes)
 		ISC_PLATFORM_HAVEIPV6="#define ISC_PLATFORM_HAVEIPV6 1"
@@ -630,11 +632,22 @@ case "$found_ipv6" in
 			 ISC_PLATFORM_NEEDIN6ADDRANY="#undef ISC_PLATFORM_NEEDIN6ADDRANY"],
 			[AC_MSG_RESULT(no)
 			 ISC_PLATFORM_NEEDIN6ADDRANY="#define ISC_PLATFORM_NEEDIN6ADDRANY 1"])
+		AC_MSG_CHECKING(for in6_pktinfo)
+		AC_TRY_LINK([
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>],
+		[struct in6_pktinfo xyzzy; return (0);],
+			[AC_MSG_RESULT(yes)
+			 ISC_PLATFORM_HAVEIN6PKTINFO="#define ISC_PLATFORM_HAVEIN6PKTINFO 1"],
+			[AC_MSG_RESULT(no -- disabling runtime ipv6 support)
+			 ISC_PLATFORM_HAVEIN6PKTINFO="#undef ISC_PLATFORM_HAVEIN6PKTINFO"])
 		;;
 	no)
 		ISC_PLATFORM_HAVEIPV6="#undef ISC_PLATFORM_HAVEIPV6"
 		LWRES_PLATFORM_HAVEIPV6="#undef LWRES_PLATFORM_HAVEIPV6"
 		ISC_PLATFORM_NEEDIN6ADDRANY="#undef ISC_PLATFORM_NEEDIN6ADDRANY"
+		ISC_PLATFORM_HAVEIN6PKTINFO="#undef ISC_PLATFORM_HAVEIN6PKTINFO"
 		ISC_IPV6_H="ipv6.h"
 		ISC_IPV6_O="ipv6.$O"
 		ISC_ISCIPV6_O="unix/ipv6.$O"
@@ -645,6 +658,7 @@ esac
 AC_SUBST(ISC_PLATFORM_HAVEIPV6)
 AC_SUBST(LWRES_PLATFORM_HAVEIPV6)
 AC_SUBST(ISC_PLATFORM_NEEDIN6ADDRANY)
+AC_SUBST(ISC_PLATFORM_HAVEIN6PKTINFO)
 AC_SUBST(ISC_IPV6_H)
 AC_SUBST(ISC_IPV6_O)
 AC_SUBST(ISC_ISCIPV6_O)

lib/isc/include/isc/ipv6.h

@@ -87,11 +87,6 @@ struct sockaddr_in6 {
 #define SIN6_LEN 1
 #endif
 
-struct in6_pktinfo {
-	struct in6_addr ipi6_addr;    /* src/dst IPv6 address */
-	unsigned int    ipi6_ifindex; /* send/recv interface index */
-};
-
 /*
  * Unspecified
  */

lib/isc/include/isc/platform.h.in

@@ -49,6 +49,12 @@
  */
 @ISC_PLATFORM_NEEDIN6ADDRANY@
 
+/*
+ * If this system has in6_pktinfo, ISC_PLATFORM_HAVEIN6PKTINFO will be
+ * defined.
+ */
+@ISC_PLATFORM_HAVEIN6PKTINFO@
+
 /*
  * If this system needs inet_ntop(), ISC_PLATFORM_NEEDNTOP will be defined.
  */

lib/isc/unix/include/isc/net.h

@@ -30,6 +30,7 @@
  *
  *		struct in_addr
  *		struct in6_addr
+ *		struct in6_pktinfo
  *		struct sockaddr
  *		struct sockaddr_in
  *		struct sockaddr_in6
@@ -90,6 +91,13 @@
 #include <isc/ipv6.h>
 #endif
 
+#ifndef ISC_PLATFORM_HAVEIN6PKTINFO
+struct in6_pktinfo {
+	struct in6_addr ipi6_addr;    /* src/dst IPv6 address */
+	unsigned int    ipi6_ifindex; /* send/recv interface index */
+};
+#endif
+
 /*
  * Cope with a missing in6addr_any.
  */

lib/isc/unix/net.c

@@ -68,7 +68,11 @@ static void
 initialize_action(void) {
 	ipv4_result = try_proto(PF_INET);
 #ifdef ISC_PLATFORM_HAVEIPV6
+#ifdef ISC_PLATFORM_HAVEIN6PKTINFO
 	ipv6_result = try_proto(PF_INET6);
+#else
+	ipv6_result = 0;
+#endif
 #endif
 }