[IP_SOCKGLUE]: Remove most of the tcp specific calls

As DCCP needs to be called in the same spots.

Now we have a member in inet_sock (is_icsk), set at sock creation time from
struct inet_protosw->flags (if INET_PROTOSW_ICSK is set, like for TCP and
DCCP) to see if a struct sock instance is a inet_connection_sock for places
like the ones in ip_sockglue.c (v4 and v6) where we previously were looking if
sk_type was SOCK_STREAM, that is insufficient because we now use the same code
for DCCP, that has sk_type SOCK_DCCP.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index af1946c..3a0a914 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -621,7 +621,7 @@
    It is minimum of user_mss and mss received with SYN.
    It also does not include TCP options.
 
-   tp->pmtu_cookie is last pmtu, seen by this function.
+   inet_csk(sk)->icsk_pmtu_cookie is last pmtu, seen by this function.
 
    tp->mss_cache is current effective sending mss, including
    all tcp options except for SACKs. It is evaluated,
@@ -631,17 +631,18 @@
    NOTE1. rfc1122 clearly states that advertised MSS
    DOES NOT include either tcp or ip options.
 
-   NOTE2. tp->pmtu_cookie and tp->mss_cache are READ ONLY outside
-   this function.			--ANK (980731)
+   NOTE2. inet_csk(sk)->icsk_pmtu_cookie and tp->mss_cache
+   are READ ONLY outside this function.		--ANK (980731)
  */
 
 unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
+	struct inet_connection_sock *icsk = inet_csk(sk);
 	/* Calculate base mss without TCP options:
 	   It is MMS_S - sizeof(tcphdr) of rfc1122
 	 */
-	int mss_now = (pmtu - inet_csk(sk)->icsk_af_ops->net_header_len -
+	int mss_now = (pmtu - icsk->icsk_af_ops->net_header_len -
 		       sizeof(struct tcphdr));
 
 	/* Clamp it (mss_clamp does not include tcp options) */
@@ -649,7 +650,7 @@
 		mss_now = tp->rx_opt.mss_clamp;
 
 	/* Now subtract optional transport overhead */
-	mss_now -= tp->ext_header_len;
+	mss_now -= icsk->icsk_ext_hdr_len;
 
 	/* Then reserve room for full set of TCP options and 8 bytes of data */
 	if (mss_now < 48)
@@ -663,7 +664,7 @@
 		mss_now = max((tp->max_window>>1), 68U - tp->tcp_header_len);
 
 	/* And store cached results */
-	tp->pmtu_cookie = pmtu;
+	icsk->icsk_pmtu_cookie = pmtu;
 	tp->mss_cache = mss_now;
 
 	return mss_now;
@@ -693,7 +694,7 @@
 
 	if (dst) {
 		u32 mtu = dst_mtu(dst);
-		if (mtu != tp->pmtu_cookie)
+		if (mtu != inet_csk(sk)->icsk_pmtu_cookie)
 			mss_now = tcp_sync_mss(sk, mtu);
 	}
 
@@ -706,7 +707,8 @@
 	if (doing_tso) {
 		xmit_size_goal = (65535 -
 				  inet_csk(sk)->icsk_af_ops->net_header_len -
-				  tp->ext_header_len - tp->tcp_header_len);
+				  inet_csk(sk)->icsk_ext_hdr_len -
+				  tp->tcp_header_len);
 
 		if (tp->max_window &&
 		    (xmit_size_goal > (tp->max_window >> 1)))