ip: pass tos into ip_build_and_send_pkt()

This commit adds tos as a new passed in parameter to
ip_build_and_send_pkt() which will be used in the later commit.
This is a pure restructure and does not have any functional change.

Signed-off-by: Wei Wang <weiwan@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index af27cfa..c4c7ad4 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -985,7 +985,8 @@ static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
 		rcu_read_lock();
 		err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
 					    ireq->ir_rmt_addr,
-					    rcu_dereference(ireq->ireq_opt));
+					    rcu_dereference(ireq->ireq_opt),
+					    inet_sk(sk)->tos);
 		rcu_read_unlock();
 		err = net_xmit_eval(err);
 	}