From 99f13ae12c53954deee9dbceb6732bbda79956e2 Mon Sep 17 00:00:00 2001
From: Alan Somers <asomers@FreeBSD.org>
Date: Wed, 21 Aug 2019 21:05:15 +0000
Subject: [PATCH] ping: add -H option for enabling reverse DNS lookup
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This is the reverse of the -n flag.

Submitted by:	Ján Sučan <sucanjan@gmail.com>
Sponsored by:	Google LLC (Google Summer of Code 2019)
Differential Revision:	https://reviews.freebsd.org/D21356
---
 sbin/ping/ping.8 | 14 +++++++++++---
 sbin/ping/ping.c |  9 ++++++---
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/sbin/ping/ping.8 b/sbin/ping/ping.8
index b674d96c67d0..14dff3414eb3 100644
--- a/sbin/ping/ping.8
+++ b/sbin/ping/ping.8
@@ -28,7 +28,7 @@
 .\"     @(#)ping.8	8.2 (Berkeley) 12/11/93
 .\" $FreeBSD$
 .\"
-.Dd March 11, 2016
+.Dd August 21, 2019
 .Dt PING 8
 .Os
 .Sh NAME
@@ -38,7 +38,7 @@
 packets to network hosts
 .Sh SYNOPSIS
 .Nm
-.Op Fl AaDdfnoQqRrv
+.Op Fl AaDdfHnoQqRrv
 .Op Fl c Ar count
 .Op Fl G Ar sweepmaxsize
 .Op Fl g Ar sweepminsize
@@ -56,7 +56,7 @@ packets to network hosts
 .Op Fl z Ar tos
 .Ar host
 .Nm
-.Op Fl AaDdfLnoQqRrv
+.Op Fl AaDdfHLnoQqRrv
 .Op Fl c Ar count
 .Op Fl I Ar iface
 .Op Fl i Ar wait
@@ -157,6 +157,14 @@ Specify the size of
 .Tn ICMP
 payload to start with when sending sweeping pings.
 The default value is 0.
+.It Fl H
+Hostname output.
+Try to do a reverse DNS lookup when displaying addresses.
+This is the opposite of
+.Fl n ,
+and it is the default behavior.
+.Nm
+utility tries reverse-lookup by default.
 .It Fl h Ar sweepincrsize
 Specify the number of bytes to increment the size of
 .Tn ICMP
diff --git a/sbin/ping/ping.c b/sbin/ping/ping.c
index d04ab651351a..445b418699d9 100644
--- a/sbin/ping/ping.c
+++ b/sbin/ping/ping.c
@@ -297,7 +297,7 @@ main(int argc, char *const *argv)
 
 	outpack = outpackhdr + sizeof(struct ip);
 	while ((ch = getopt(argc, argv,
-		"Aac:DdfG:g:h:I:i:Ll:M:m:nop:QqRrS:s:T:t:vW:z:"
+		"Aac:DdfG:g:Hh:I:i:Ll:M:m:nop:QqRrS:s:T:t:vW:z:"
 #ifdef IPSEC
 #ifdef IPSEC_POLICY_IPSEC
 		"P:"
@@ -363,6 +363,9 @@ main(int argc, char *const *argv)
 			options |= F_SWEEP;
 			sweepmin = ltmp;
 			break;
+		case 'H':
+			options &= ~F_NUMERIC;
+			break;
 		case 'h': /* Packet size increment for ping sweep */
 			ltmp = strtol(optarg, &ep, 0);
 			if (*ep || ep == optarg || ltmp < 1)
@@ -1743,11 +1746,11 @@ usage(void)
 {
 
 	(void)fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n%s\n",
-"usage: ping [-AaDdfnoQqRrv] [-c count] [-G sweepmaxsize] [-g sweepminsize]",
+"usage: ping [-AaDdfHnoQqRrv] [-c count] [-G sweepmaxsize] [-g sweepminsize]",
 "            [-h sweepincrsize] [-i wait] [-l preload] [-M mask | time] [-m ttl]",
 "           " SECOPT " [-p pattern] [-S src_addr] [-s packetsize] [-t timeout]",
 "            [-W waittime] [-z tos] host",
-"       ping [-AaDdfLnoQqRrv] [-c count] [-I iface] [-i wait] [-l preload]",
+"       ping [-AaDdfHLnoQqRrv] [-c count] [-I iface] [-i wait] [-l preload]",
 "            [-M mask | time] [-m ttl]" SECOPT " [-p pattern] [-S src_addr]",
 "            [-s packetsize] [-T ttl] [-t timeout] [-W waittime]",
 "            [-z tos] mcast-group");