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authorDavid Ward <david.ward@ll.mit.edu>2013-01-27 13:04:58 +0000
committerDavid S. Miller <davem@davemloft.net>2013-01-29 14:05:28 -0500
commit040468a0a7b3f9c7966126d98151bc64f1423657 (patch)
tree454a47cf1a533492017579efe7658fc3b8496922 /net/ipv4/ip_gre.c
parent5c766d642bcaffd0c2a5b354db2068515b3846cf (diff)
downloadlinux-040468a0a7b3f9c7966126d98151bc64f1423657.tar.bz2
ip_gre: When TOS is inherited, use configured TOS value for non-IP packets
A GRE tunnel can be configured so that outgoing tunnel packets inherit the value of the TOS field from the inner IP header. In doing so, when a non-IP packet is transmitted through the tunnel, the TOS field will always be set to 0. Instead, the user should be able to configure a different TOS value as the fallback to use for non-IP packets. This is helpful when the non-IP packets are all control packets and should be handled by routers outside the tunnel as having Internet Control precedence. One example of this is the NHRP packets that control a DMVPN-compatible mGRE tunnel; they are encapsulated directly by GRE and do not contain an inner IP header. Under the existing behavior, the IFLA_GRE_TOS parameter must be set to '1' for the TOS value to be inherited. Now, only the least significant bit of this parameter must be set to '1', and when a non-IP packet is sent through the tunnel, the upper 6 bits of this same parameter will be copied into the TOS field. (The ECN bits get masked off as before.) This behavior is backwards-compatible with existing configurations and iproute2 versions. Signed-off-by: David Ward <david.ward@ll.mit.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/ip_gre.c')
-rw-r--r--net/ipv4/ip_gre.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index af6be70821c4..801e02355ec4 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -820,8 +820,8 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
ttl = tiph->ttl;
tos = tiph->tos;
- if (tos == 1) {
- tos = 0;
+ if (tos & 0x1) {
+ tos &= ~0x1;
if (skb->protocol == htons(ETH_P_IP))
tos = old_iph->tos;
else if (skb->protocol == htons(ETH_P_IPV6))