Honour -n when setting entries

Just like avoiding reverse lookups when printing entries or not resolving
hostnames when deleting entries, make -n effect setting entries as well;
just like pfctl(8)'s -N from which the manual wording was copied verbatim.

OK deraadt

2 files changed, 7 insertions, 4 deletions

diff --git a/usr.sbin/ndp/ndp.8 b/usr.sbin/ndp/ndp.8
index d622e584ab5..62cdaa8a2b3 100644
--- a/usr.sbin/ndp/ndp.8
+++ b/usr.sbin/ndp/ndp.8
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: ndp.8,v 1.45 2017/08/09 14:36:00 florian Exp $
+.\"	$OpenBSD: ndp.8,v 1.46 2019/08/23 15:41:59 kn Exp $
 .\"	$KAME: ndp.8,v 1.28 2002/07/17 08:46:33 itojun Exp $
 .\"
 .\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
@@ -28,7 +28,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: August 9 2017 $
+.Dd $Mdocdate: August 23 2019 $
 .Dt NDP 8
 .Os
 .Sh NAME
@@ -122,7 +122,8 @@ option for a description of the file format.
 .It Fl i Ar interface
 View ND information for the specified interface.
 .It Fl n
-Do not try to resolve numeric addresses to hostnames.
+Do not perform domain name resolution.
+If a name cannot be resolved without DNS, an error will be reported.
 .It Xo
 .Fl s Ar nodename ether_addr
 .Op Cm temp
diff --git a/usr.sbin/ndp/ndp.c b/usr.sbin/ndp/ndp.c
index 71391565ec1..38d795c3015 100644
--- a/usr.sbin/ndp/ndp.c
+++ b/usr.sbin/ndp/ndp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ndp.c,v 1.94 2019/08/22 19:33:57 kn Exp $	*/
+/*	$OpenBSD: ndp.c,v 1.95 2019/08/23 15:41:59 kn Exp $	*/
 /*	$KAME: ndp.c,v 1.101 2002/07/17 08:46:33 itojun Exp $	*/
 
 /*
@@ -330,6 +330,8 @@ set(int argc, char **argv)
 
 	bzero(&hints, sizeof(hints));
 	hints.ai_family = AF_INET6;
+	if (nflag)
+		hints.ai_flags = AI_NUMERICHOST;
 	gai_error = getaddrinfo(host, NULL, &hints, &res);
 	if (gai_error) {
 		warnx("%s: %s", host, gai_strerror(gai_error));