[NET]: Introduce inet_connection_sock

This creates struct inet_connection_sock, moving members out of struct
tcp_sock that are shareable with other INET connection oriented
protocols, such as DCCP, that in my private tree already uses most of
these members.

The functions that operate on these members were renamed, using a
inet_csk_ prefix while not being moved yet to a new file, so as to
ease the review of these changes.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 8b6cd8d..5682370 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -271,7 +271,8 @@
 
 	if (tw != NULL) {
 		struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
-		const int rto = (tp->rto << 2) - (tp->rto >> 1);
+		const struct inet_connection_sock *icsk = inet_csk(sk);
+		const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
 
 		tw->tw_rcv_wscale	= tp->rx_opt.rcv_wscale;
 		tcptw->tw_rcv_nxt	= tp->rcv_nxt;
@@ -605,10 +606,11 @@
 		struct inet_request_sock *ireq = inet_rsk(req);
 		struct tcp_request_sock *treq = tcp_rsk(req);
 		struct inet_sock *newinet = inet_sk(newsk);
+		struct inet_connection_sock *newicsk = inet_csk(newsk);
 		struct tcp_sock *newtp;
 
 		newsk->sk_state = TCP_SYN_RECV;
-		newinet->bind_hash = NULL;
+		newicsk->icsk_bind_hash = NULL;
 
 		/* Clone the TCP header template */
 		newinet->dport = ireq->rmt_port;
@@ -624,11 +626,11 @@
 
 		tcp_init_wl(newtp, treq->snt_isn, treq->rcv_isn);
 
-		newtp->retransmits = 0;
-		newtp->backoff = 0;
+		newicsk->icsk_retransmits = 0;
+		newicsk->icsk_backoff = 0;
 		newtp->srtt = 0;
 		newtp->mdev = TCP_TIMEOUT_INIT;
-		newtp->rto = TCP_TIMEOUT_INIT;
+		newicsk->icsk_rto = TCP_TIMEOUT_INIT;
 
 		newtp->packets_out = 0;
 		newtp->left_out = 0;
@@ -667,11 +669,11 @@
 		newtp->rx_opt.num_sacks = 0;
 		newtp->urg_data = 0;
 		/* Deinitialize accept_queue to trap illegal accesses. */
-		memset(&newtp->accept_queue, 0, sizeof(newtp->accept_queue));
+		memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));
 
 		if (sock_flag(newsk, SOCK_KEEPOPEN))
-			tcp_reset_keepalive_timer(newsk,
-						  keepalive_time_when(newtp));
+			inet_csk_reset_keepalive_timer(newsk,
+						       keepalive_time_when(newtp));
 
 		newtp->rx_opt.tstamp_ok = ireq->tstamp_ok;
 		if((newtp->rx_opt.sack_ok = ireq->sack_ok) != 0) {
@@ -701,7 +703,7 @@
 			newtp->tcp_header_len = sizeof(struct tcphdr);
 		}
 		if (skb->len >= TCP_MIN_RCVMSS+newtp->tcp_header_len)
-			newtp->ack.last_seg_size = skb->len-newtp->tcp_header_len;
+			newicsk->icsk_ack.last_seg_size = skb->len - newtp->tcp_header_len;
 		newtp->rx_opt.mss_clamp = req->mss;
 		TCP_ECN_openreq_child(newtp, req);
 		if (newtp->ecn_flags&TCP_ECN_OK)
@@ -881,10 +883,10 @@
 		if (child == NULL)
 			goto listen_overflow;
 
-		tcp_synq_unlink(tp, req, prev);
-		tcp_synq_removed(sk, req);
+		inet_csk_reqsk_queue_unlink(sk, req, prev);
+		inet_csk_reqsk_queue_removed(sk, req);
 
-		tcp_acceptq_queue(sk, req, child);
+		inet_csk_reqsk_queue_add(sk, req, child);
 		return child;
 
 	listen_overflow:
@@ -898,7 +900,7 @@
 		if (!(flg & TCP_FLAG_RST))
 			req->rsk_ops->send_reset(skb);
 
-		tcp_synq_drop(sk, req, prev);
+		inet_csk_reqsk_queue_drop(sk, req, prev);
 		return NULL;
 }