Index: sys/netinet/tcp_input.c
===================================================================
--- sys/netinet/tcp_input.c
+++ sys/netinet/tcp_input.c
@@ -1501,7 +1501,7 @@
 {
 	int thflags, acked, ourfinisacked, needoutput = 0, sack_changed;
 	int rstreason, todrop, win;
-	u_long tiwin;
+	uint32_t tiwin;
 	char *s;
 	struct in_conninfo *inc;
 	struct mbuf *mfree;
Index: sys/netinet/tcp_stacks/fastpath.c
===================================================================
--- sys/netinet/tcp_stacks/fastpath.c
+++ sys/netinet/tcp_stacks/fastpath.c
@@ -169,7 +169,7 @@
 static void
 tcp_do_fastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
 	       struct tcpcb *tp, struct tcpopt *to, int drop_hdrlen, int tlen, 
-	       int ti_locked, u_long tiwin)
+	       int ti_locked, uint32_t tiwin)
 {
 	int acked;
 	int winup_only=0;
@@ -340,7 +340,7 @@
 static void
 tcp_do_fastnewdata(struct mbuf *m, struct tcphdr *th, struct socket *so,
 		   struct tcpcb *tp, struct tcpopt *to, int drop_hdrlen, int tlen, 
-		   int ti_locked, u_long tiwin)
+		   int ti_locked, uint32_t tiwin)
 {
 	int newsize = 0;	/* automatic sockbuf scaling */
 #ifdef TCPDEBUG
@@ -498,7 +498,7 @@
 static void
 tcp_do_slowpath(struct mbuf *m, struct tcphdr *th, struct socket *so,
 		struct tcpcb *tp, struct tcpopt *to, int drop_hdrlen, int tlen, 
-		int ti_locked, u_long tiwin, int thflags)
+		int ti_locked, uint32_t tiwin, int thflags)
 {
 	int  acked, ourfinisacked, needoutput = 0;
 	int rstreason, todrop, win;
@@ -1756,7 +1756,7 @@
 			int ti_locked)
 {
 	int thflags;
-	u_long tiwin;
+	uint32_t tiwin;
 	char *s;
 	int can_enter;
 	struct in_conninfo *inc;
@@ -1980,7 +1980,7 @@
 static int
 tcp_fastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
 	       struct tcpcb *tp, struct tcpopt *to, int drop_hdrlen, int tlen, 
-	       int ti_locked, u_long tiwin)
+	       int ti_locked, uint32_t tiwin)
 {
 	int acked;
 	int winup_only=0;
@@ -2199,7 +2199,7 @@
 		       int ti_locked)
 {
 	int thflags;
-	u_long tiwin;
+	uint32_t tiwin;
 	char *s;
 	struct in_conninfo *inc;
 	struct tcpopt to;