ipv6/ping: set skb->mark on icmpv6 sockets

IPv6 ping sockets route based on fwmark, but do not yet set skb->mark.
Add this. IPv4 ping sockets also do both.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/ping.c

@@ -114,6 +114,7 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 
 	ipcm6_init_sk(&ipc6, np);
+	ipc6.sockc.mark = sk->sk_mark;
 	fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
 
 	dst = ip6_sk_dst_lookup_flow(sk, &fl6, daddr, false);