Patchwork [RFC] gre: propagate ipv6 transport class

mail settings
Submitter stephen hemminger
Date July 6, 2010, 5:58 p.m.
Message ID <20100706105821.7b0e2538@nehalam>
Download mbox | patch
Permalink /patch/58051/
State Accepted
Delegated to: David Miller
Headers show


stephen hemminger - July 6, 2010, 5:58 p.m.
This patch makes IPV6 over IPv4 GRE tunnel propagate the transport
class field from the underlying IPV6 header to the IPV4 Type Of Service
field. Without the patch, all IPV6 packets in tunnel look the same to QoS.

This assumes that IPV6 transport class is exactly the same
as IPv4 TOS. Not sure if that is always the case?  Maybe need
to mask off some bits.

The mask and shift to get tclass is copied from ipv6/datagram.c

Signed-off-by: Stephen Hemminger <>

To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to
More majordomo info at


--- a/net/ipv4/ip_gre.c	2010-07-06 08:52:03.702096234 -0700
+++ b/net/ipv4/ip_gre.c	2010-07-06 08:59:18.416738831 -0700
@@ -731,6 +731,8 @@  static netdev_tx_t ipgre_tunnel_xmit(str
 		tos = 0;
 		if (skb->protocol == htons(ETH_P_IP))
 			tos = old_iph->tos;
+		else if (skb->protocol == htons(ETH_P_IPV6))
+			tos = (ntohl(*(__be32 *)ipv6_hdr(skb)) >> 20) & 0xff;