ipv6: copy traffic class from ping request to reply

Suggested-by: Simon Schneider <simon-schneider@gmx.net>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/icmp.c

@@ -67,6 +67,7 @@
 #include <net/icmp.h>
 #include <net/xfrm.h>
 #include <net/inet_common.h>
+#include <net/dsfield.h>
 
 #include <asm/uaccess.h>
 
@@ -553,6 +554,7 @@ static void icmpv6_echo_reply(struct sk_buff *skb)
 	struct dst_entry *dst;
 	int err = 0;
 	int hlimit;
+	u8 tclass;
 
 	saddr = &ipv6_hdr(skb)->daddr;
 
@@ -603,8 +605,9 @@ static void icmpv6_echo_reply(struct sk_buff *skb)
 	msg.offset = 0;
 	msg.type = ICMPV6_ECHO_REPLY;
 
+	tclass = ipv6_get_dsfield(ipv6_hdr(skb));
 	err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
-				sizeof(struct icmp6hdr), hlimit, np->tclass, NULL, &fl6,
+				sizeof(struct icmp6hdr), hlimit, tclass, NULL, &fl6,
 				(struct rt6_info *)dst, MSG_DONTWAIT,
 				np->dontfrag);