Index: tcp_stacks/fastpath.c
===================================================================
--- tcp_stacks/fastpath.c
+++ tcp_stacks/fastpath.c
@@ -2376,34 +2376,17 @@
 }
 
 struct tcp_function_block __tcp_fastslow = {
-	"fastslow",
-	tcp_output,
-	tcp_do_segment_fastslow,
-	tcp_default_ctloutput,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	0,
-	0
-
+	.tfb_tcp_block_name = "fastslow",
+	.tfb_tcp_output = tcp_output,
+	.tfb_tcp_do_segment = tcp_do_segment_fastslow,
+	.tfb_tcp_ctloutput = tcp_default_ctloutput,
 };
 
 struct tcp_function_block __tcp_fastack = {
-	"fastack",
-	tcp_output,
-	tcp_do_segment_fastack,
-	tcp_default_ctloutput,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	NULL,
-	0,
-	0
+	.tfb_tcp_block_name = "fastack",
+	.tfb_tcp_output = tcp_output,
+	.tfb_tcp_do_segment = tcp_do_segment_fastack,
+	.tfb_tcp_ctloutput = tcp_default_ctloutput
 };
 
 static int
Index: tcp_timer.c
===================================================================
--- tcp_timer.c
+++ tcp_timer.c
@@ -604,6 +604,10 @@
 	KASSERT((tp->t_timers->tt_flags & TT_REXMT) != 0,
 		("%s: tp %p rexmt callout should be running", __func__, tp));
 	tcp_free_sackholes(tp);
+	if (tp->t_fb->tfb_tcp_rexmit_tmr) {
+		/* The stack has a timer action too. */
+		(*tp->t_fb->tfb_tcp_rexmit_tmr)(tp);
+	}
 	/*
 	 * Retransmission timer went off.  Message has not
 	 * been acked within retransmit interval.  Back off
Index: tcp_var.h
===================================================================
--- tcp_var.h
+++ tcp_var.h
@@ -135,6 +135,7 @@
 			    uint32_t, u_int);
 	int	(*tfb_tcp_timer_active)(struct tcpcb *, uint32_t);
 	void	(*tfb_tcp_timer_stop)(struct tcpcb *, uint32_t);
+	void	(*tfb_tcp_rexmit_tmr)(struct tcpcb *);
 	volatile uint32_t tfb_refcnt;
 	uint32_t  tfb_flags;
 };