netdev - [PATCH iproute2 2/3] gre6/tunnel: Do not submit garbage in flowinfo

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Date:   Wed, 27 Dec 2017 13:28:15 +0200
From:   Serhey Popovych <serhe.popovych@...il.com>
To:     netdev@...r.kernel.org
Subject: [PATCH iproute2 2/3] gre6/tunnel: Do not submit garbage in flowinfo

We always send flowinfo to the kernel. If flowlabel/tclass
was set first to non-inherit value and then reset to
inherit we do not clear flowlabel/tclass part in flowinfo,
send it to kernel and can get from the kernel back.

Even if we check for IP6_TNL_F_USE_ORIG_TCLASS and
IP6_TNL_F_USE_ORIG_FLOWLABEL when printing options
sending invalid flowlabel/tclass to the kernel seems
bad idea.

Note that ip6tnl always clean corresponding flowinfo
parts on inherit.

Signed-off-by: Serhey Popovych <serhe.popovych@...il.com>
---
 ip/link_gre6.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/ip/link_gre6.c b/ip/link_gre6.c
index a3e8e08..7ae4b49 100644
--- a/ip/link_gre6.c
+++ b/ip/link_gre6.c
@@ -251,12 +251,12 @@ get_failed:
 			__u8 uval;
 
 			NEXT_ARG();
+			flowinfo &= ~IP6_FLOWINFO_TCLASS;
 			if (strcmp(*argv, "inherit") == 0)
 				flags |= IP6_TNL_F_USE_ORIG_TCLASS;
 			else {
 				if (get_u8(&uval, *argv, 16))
 					invarg("invalid TClass", *argv);
-				flowinfo &= ~IP6_FLOWINFO_TCLASS;
 				flowinfo |= htonl((__u32)uval << 20) & IP6_FLOWINFO_TCLASS;
 				flags &= ~IP6_TNL_F_USE_ORIG_TCLASS;
 			}
@@ -265,6 +265,7 @@ get_failed:
 			__u32 uval;
 
 			NEXT_ARG();
+			flowinfo &= ~IP6_FLOWINFO_FLOWLABEL;
 			if (strcmp(*argv, "inherit") == 0)
 				flags |= IP6_TNL_F_USE_ORIG_FLOWLABEL;
 			else {
@@ -272,7 +273,6 @@ get_failed:
 					invarg("invalid Flowlabel", *argv);
 				if (uval > 0xFFFFF)
 					invarg("invalid Flowlabel", *argv);
-				flowinfo &= ~IP6_FLOWINFO_FLOWLABEL;
 				flowinfo |= htonl(uval) & IP6_FLOWINFO_FLOWLABEL;
 				flags &= ~IP6_TNL_F_USE_ORIG_FLOWLABEL;
 			}
-- 
1.7.10.4