[DCCP]: Introduce dccp_write_xmit from code in dccp_sendmsg

This way it gets closer to the TCP flow, where congestion window
checks are done, it seems we can map ccid_hc_tx_send_packet in
dccp_write_xmit to tcp_snd_wnd_test in tcp_write_xmit, a CCID2
decision should just fit in here as well...

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 55b690a..8a0d7af 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -122,6 +122,9 @@
 extern void dccp_send_delayed_ack(struct sock *sk);
 extern void dccp_send_sync(struct sock *sk, u64 seq);
 
+extern int dccp_write_xmit(struct sock *sk, struct sk_buff *skb,
+			   const int len);
+
 extern void dccp_init_xmit_timers(struct sock *sk);
 static inline void dccp_clear_xmit_timers(struct sock *sk)
 {
@@ -194,8 +197,6 @@
 	req->rcv_wnd = 0;
 }
 
-extern void dccp_v4_send_check(struct sock *sk, struct dccp_hdr *dh, int len, 
-			       struct sk_buff *skb);
 extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
 
 extern struct sock *dccp_create_openreq_child(struct sock *sk,