Index: head/sys/netinet/tcp_output.c
===================================================================
--- head/sys/netinet/tcp_output.c
+++ head/sys/netinet/tcp_output.c
@@ -336,7 +336,7 @@
 			sendalot = 1;
 			TCPSTAT_INC(tcps_sack_rexmits);
 			TCPSTAT_ADD(tcps_sack_rexmit_bytes,
-			    min(len, tp->t_maxseg));
+			    min(len, tcp_maxseg(tp)));
 		}
 	}
 after_sack_rexmit:
@@ -858,7 +858,6 @@
 			if (flags & TH_SYN)
 				to.to_flags |= TOF_SACKPERM;
 			else if (TCPS_HAVEESTABLISHED(tp->t_state) &&
-			    (tp->t_flags & TF_SACK_PERMIT) &&
 			    tp->rcv_numsacks > 0) {
 				to.to_flags |= TOF_SACK;
 				to.to_nsacks = tp->rcv_numsacks;
Index: head/sys/netinet/tcp_sack.c
===================================================================
--- head/sys/netinet/tcp_sack.c
+++ head/sys/netinet/tcp_sack.c
@@ -787,15 +787,16 @@
 tcp_sack_partialack(struct tcpcb *tp, struct tcphdr *th)
 {
 	int num_segs = 1;
+	u_int maxseg = tcp_maxseg(tp);
 
 	INP_WLOCK_ASSERT(tp->t_inpcb);
 	tcp_timer_activate(tp, TT_REXMT, 0);
 	tp->t_rtttime = 0;
 	/* Send one or 2 segments based on how much new data was acked. */
-	if ((BYTES_THIS_ACK(tp, th) / tp->t_maxseg) >= 2)
+	if ((BYTES_THIS_ACK(tp, th) / maxseg) >= 2)
 		num_segs = 2;
 	tp->snd_cwnd = (tp->sackhint.sack_bytes_rexmit +
-	    (tp->snd_nxt - tp->snd_recover) + num_segs * tp->t_maxseg);
+	    (tp->snd_nxt - tp->snd_recover) + num_segs * maxseg);
 	if (tp->snd_cwnd > tp->snd_ssthresh)
 		tp->snd_cwnd = tp->snd_ssthresh;
 	tp->t_flags |= TF_ACKNOW;