Grab a snap amount of TCP connections in syncache from tcpstat.

sys/netinet/tcp_subr.c

@@ -1590,7 +1590,8 @@ tcp_pcblist(SYSCTL_HANDLER_ARGS)
 	 * resource-intensive to repeat twice on every request.
 	 */
 	if (req->oldptr == NULL) {
-		n = V_tcbinfo.ipi_count + syncache_pcbcount();
+		n = V_tcbinfo.ipi_count +
+		    TCPSTAT_FETCH(tcps_states[TCPS_SYN_RECEIVED]);
 		n += imax(n / 8, 10);
 		req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xtcpcb);
 		return (0);
@@ -1607,7 +1608,7 @@ tcp_pcblist(SYSCTL_HANDLER_ARGS)
 	n = V_tcbinfo.ipi_count;
 	INP_LIST_RUNLOCK(&V_tcbinfo);
 
-	m = syncache_pcbcount();
+	m = TCPSTAT_FETCH(tcps_states[TCPS_SYN_RECEIVED]);
 
 	error = sysctl_wire_old_buffer(req, 2 * (sizeof xig)
 		+ (n + m) * sizeof(struct xtcpcb));

sys/netinet/tcp_syncache.c

@@ -2099,25 +2099,6 @@ syncookie_reseed(void *arg)
 	callout_schedule(&sc->secret.reseed, SYNCOOKIE_LIFETIME * hz);
 }
 
-/*
- * Returns the current number of syncache entries.  This number
- * will probably change before you get around to calling 
- * syncache_pcblist.
- */
-int
-syncache_pcbcount(void)
-{
-	struct syncache_head *sch;
-	int count, i;
-
-	for (count = 0, i = 0; i < V_tcp_syncache.hashsize; i++) {
-		/* No need to lock for a read. */
-		sch = &V_tcp_syncache.hashbase[i];
-		count += sch->sch_length;
-	}
-	return count;
-}
-
 /*
  * Exports the syncache entries to userland so that netstat can display
  * them alongside the other sockets.  This function is intended to be

sys/netinet/tcp_syncache.h

@@ -46,7 +46,6 @@ int	 syncache_add(struct in_conninfo *, struct tcpopt *,
 	     void *, void *);
 void	 syncache_chkrst(struct in_conninfo *, struct tcphdr *);
 void	 syncache_badack(struct in_conninfo *);
-int	 syncache_pcbcount(void);
 int	 syncache_pcblist(struct sysctl_req *req, int max_pcbs, int *pcbs_exported);
 
 struct syncache {