netdev - Re: [PATCH] iputils/ping_common.c: avoid gethostbyaddr during ping flood

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Date:	Thu, 17 Jun 2010 01:08:43 +0000 (UTC)
From:	Chris Caputo <ccaputo@....net>
To:	netdev@...r.kernel.org, Yoshifuji Hideaki <yoshfuji@...uff.net>
Subject: Re: [PATCH] iputils/ping_common.c: avoid gethostbyaddr during ping
	flood 

On Wed, 6 Feb 2008, Chris Caputo wrote:
> Unless a destination is specified by IP address, a ping flood results in a 
> gethostbyaddr() for every echo reply.  Thus a DNS flood can accompany a 
> ping flood.

Updated for iputils-s20100418...  Can someone review and work into next 
release?

Thanks,
Chris

---
Unless a destination is specified by IP address, a ping flood results in a
gethostbyaddr() for every echo reply.  Thus a DNS flood can accompany a
ping flood.

This patch makes it so a gethostbyaddr() is not performed with each echo
reply during a ping flood.

Signed-off-by: Chris Caputo <ccaputo@....net>
-------
--- iputils-s20100418/ping_common.c	2010-04-18 04:45:45.000000000 +0000
+++ iputils-dev/ping_common.c	2010-06-17 01:00:59.000000000 +0000
@@ -118,10 +118,6 @@ void common_options(int ch)
 	case 'D':
 		options |= F_PTIMEOFDAY;
 		break;
-	case 'f':
-		options |= F_FLOOD;
-		setbuf(stdout, (char *)NULL);
-		break;
 	case 'i':		/* wait between sending packets */
 	{
 		if (strchr(optarg, '.')) {
@@ -183,6 +179,10 @@ void common_options(int ch)
 			exit(2);
 		}
 		break;
+	case 'f':
+		options |= F_FLOOD;
+		setbuf(stdout, (char *)NULL);
+		/* fallthrough to numeric - avoid gethostbyaddr during flood */
 	case 'n':
 		options |= F_NUMERIC;
 		break;
--
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