Remove the ss_fltsz and ss_fltsz_local sysctl's which have

long been superseded by the RFC3390 initial CWND sizing.

Also remove the remnants of TCP_METRICS_CWND which used the
TCP hostcache to set the initial CWND in a non-RFC compliant
way.

MFC after:	1 week

sys/netinet/tcp_input.c

@@ -301,9 +301,6 @@ cc_conn_init(struct tcpcb *tp)
 	struct hc_metrics_lite metrics;
 	struct inpcb *inp = tp->t_inpcb;
 	int rtt;
-#ifdef INET6
-	int isipv6 = ((inp->inp_vflag & INP_IPV6) != 0) ? 1 : 0;
-#endif
 
 	INP_WLOCK_ASSERT(tp->t_inpcb);
 
@@ -337,49 +334,16 @@ cc_conn_init(struct tcpcb *tp)
 	}
 
 	/*
-	 * Set the slow-start flight size depending on whether this
+	 * Set the initial slow-start flight size.
-	 * is a local network or not.
-	 *
-	 * Extend this so we cache the cwnd too and retrieve it here.
-	 * Make cwnd even bigger than RFC3390 suggests but only if we
-	 * have previous experience with the remote host. Be careful
-	 * not make cwnd bigger than remote receive window or our own
-	 * send socket buffer. Maybe put some additional upper bound
-	 * on the retrieved cwnd. Should do incremental updates to
-	 * hostcache when cwnd collapses so next connection doesn't
-	 * overloads the path again.
-	 *
-	 * XXXAO: Initializing the CWND from the hostcache is broken
-	 * and in its current form not RFC conformant.  It is disabled
-	 * until fixed or removed entirely.
 	 *
 	 * RFC3390 says only do this if SYN or SYN/ACK didn't got lost.
-	 * We currently check only in syncache_socket for that.
+	 * XXX: We currently check only in syncache_socket for that.
 	 */
-/* #define TCP_METRICS_CWND */
-#ifdef TCP_METRICS_CWND
-	if (metrics.rmx_cwnd)
-		tp->snd_cwnd = max(tp->t_maxseg, min(metrics.rmx_cwnd / 2,
-		    min(tp->snd_wnd, so->so_snd.sb_hiwat)));
-	else
-#endif
 	if (V_tcp_do_rfc3390)
 		tp->snd_cwnd = min(4 * tp->t_maxseg,
 		    max(2 * tp->t_maxseg, 4380));
-#ifdef INET6
-	else if (isipv6 && in6_localaddr(&inp->in6p_faddr))
-		tp->snd_cwnd = tp->t_maxseg * V_ss_fltsz_local;
-#endif
-#if defined(INET) && defined(INET6)
-	else if (!isipv6 && in_localaddr(inp->inp_faddr))
-		tp->snd_cwnd = tp->t_maxseg * V_ss_fltsz_local;
-#endif
-#ifdef INET
-	else if (in_localaddr(inp->inp_faddr))
-		tp->snd_cwnd = tp->t_maxseg * V_ss_fltsz_local;
-#endif
 	else
-		tp->snd_cwnd = tp->t_maxseg * V_ss_fltsz;
+		tp->snd_cwnd = tp->t_maxseg;
 
 	if (CC_ALGO(tp)->conn_init != NULL)
 		CC_ALGO(tp)->conn_init(tp->ccv);

sys/netinet/tcp_output.c

@@ -89,16 +89,6 @@ SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, path_mtu_discovery, CTLFLAG_RW,
 	&VNET_NAME(path_mtu_discovery), 1,
 	"Enable Path MTU Discovery");
 
-VNET_DEFINE(int, ss_fltsz) = 1;
-SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, slowstart_flightsize, CTLFLAG_RW,
-	&VNET_NAME(ss_fltsz), 1,
-	"Slow start flight size");
-
-VNET_DEFINE(int, ss_fltsz_local) = 4;
-SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, local_slowstart_flightsize,
-	CTLFLAG_RW, &VNET_NAME(ss_fltsz_local), 1,
-	"Slow start flight size for local networks");
-
 VNET_DEFINE(int, tcp_do_tso) = 1;
 #define	V_tcp_do_tso		VNET(tcp_do_tso)
 SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, tso, CTLFLAG_RW,

sys/netinet/tcp_var.h

@@ -609,8 +609,6 @@ VNET_DECLARE(int, tcp_do_rfc3390);
 VNET_DECLARE(int, tcp_sendspace);
 VNET_DECLARE(int, tcp_recvspace);
 VNET_DECLARE(int, path_mtu_discovery);
-VNET_DECLARE(int, ss_fltsz);
-VNET_DECLARE(int, ss_fltsz_local);
 VNET_DECLARE(int, tcp_do_rfc3465);
 VNET_DECLARE(int, tcp_abc_l_var);
 #define	V_tcb			VNET(tcb)
@@ -623,8 +621,6 @@ VNET_DECLARE(int, tcp_abc_l_var);
 #define	V_tcp_sendspace		VNET(tcp_sendspace)
 #define	V_tcp_recvspace		VNET(tcp_recvspace)
 #define	V_path_mtu_discovery	VNET(path_mtu_discovery)
-#define	V_ss_fltsz		VNET(ss_fltsz)
-#define	V_ss_fltsz_local	VNET(ss_fltsz_local)
 #define	V_tcp_do_rfc3465	VNET(tcp_do_rfc3465)
 #define	V_tcp_abc_l_var		VNET(tcp_abc_l_var)