ipv6: Introduce ip6_flow_hdr() to fill version, tclass and flowlabel.

This is not only for readability but also for optimization.
What we do here is to build the 32bit word at the beginning of the ipv6
header (the "ip6_flow" virtual member of struct ip6_hdr in RFC3542) and
we do not need to read the tclass portion of the target buffer.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 3 deletions

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index a14f28b280f5..fff83cbc197f 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1030,9 +1030,7 @@ static int ip6_tnl_xmit2(struct sk_buff *skb,
         skb_push(skb, sizeof(struct ipv6hdr));
         skb_reset_network_header(skb);
         ipv6h = ipv6_hdr(skb);
-        *(__be32*)ipv6h = fl6->flowlabel | htonl(0x60000000);
-        dsfield = INET_ECN_encapsulate(0, dsfield);
-        ipv6_change_dsfield(ipv6h, ~INET_ECN_MASK, dsfield);
+        ip6_flow_hdr(ipv6h, INET_ECN_encapsulate(0, dsfield), fl6->flowlabel);
         ipv6h->hop_limit = t->parms.hop_limit;
         ipv6h->nexthdr = proto;
         ipv6h->saddr = fl6->saddr;