From f5dde2a92fbb7bb043f9f3d816b168ddcaf19b6c Mon Sep 17 00:00:00 2001
From: kp <kp@FreeBSD.org>
Date: Tue, 2 Aug 2016 15:41:42 +0000
Subject: [PATCH] pfctl: Allow TOS bits to be cleared
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TOS value 0 is valid, so use 256 as an invalid value rather than zero.
This allows users to enforce TOS == 0 with pf.

Reported by:	Radek Krejča <radek.krejca@starnet.cz>
---
 sbin/pfctl/parse.y | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sbin/pfctl/parse.y b/sbin/pfctl/parse.y
index c7727d8a3a3..9f22b7391ee 100644
--- a/sbin/pfctl/parse.y
+++ b/sbin/pfctl/parse.y
@@ -3607,7 +3607,7 @@ tos	: STRING			{
 		}
 		| NUMBER			{
 			$$ = $1;
-			if (!$$ || $$ > 255) {
+			if ($$ < 0 || $$ > 255) {
 				yyerror("illegal tos value %s", $1);
 				YYERROR;
 			}