From 101f9fc84618c5b12efda54399c7604303171baa Mon Sep 17 00:00:00 2001
From: Peter Wemm <peter@FreeBSD.org>
Date: Fri, 19 Jan 1996 08:00:58 +0000
Subject: [PATCH] Change the default local address range for IP from 1024
 through 5000 to 20000 through 30000.  These numbers are used for local IP
 port numbers when an explicit address is not specified.

The values are sysctl modifiable under: net.inet.ip.port_{first|last}_auto

These numbers do not overlap with any known server addresses, without going
above 32768 which are "negative" on some other implementations.

20000 through 30000 is 2.5 times larger than the old range, but some have
suggested even that may not be enough... (gasp!)  Setting a low address
of 10000 should be plenty.. :-)
---
 sys/netinet/in.h     | 16 +++++++++++++++-
 sys/netinet/in_pcb.c | 22 ++++++++++++++++++----
 2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/sys/netinet/in.h b/sys/netinet/in.h
index 175269ea07d8..48f5fab7018e 100644
--- a/sys/netinet/in.h
+++ b/sys/netinet/in.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)in.h	8.3 (Berkeley) 1/3/94
- * $Id: in.h,v 1.12 1995/11/01 17:18:26 wollman Exp $
+ * $Id: in.h,v 1.13 1995/11/14 20:33:57 phk Exp $
  */
 
 #ifndef _NETINET_IN_H_
@@ -74,6 +74,20 @@
 #define	IPPORT_RESERVED		1024
 #define	IPPORT_USERRESERVED	5000
 
+/*
+ * Range of ports for automatic assignment to local addresses that
+ * have not explicitly specified an address.
+ *
+ * These can be overridden at kernel config time, and are used to init
+ * sysctl variables.  The sysctl variables can be changed at runtime.
+ */
+#ifndef IPPORT_FIRSTAUTO
+#define	IPPORT_FIRSTAUTO	20000
+#endif
+#ifndef IPPORT_LASTAUTO
+#define	IPPORT_LASTAUTO		30000
+#endif
+
 /*
  * Internet address (a structure for historical reasons)
  */
diff --git a/sys/netinet/in_pcb.c b/sys/netinet/in_pcb.c
index 73d564f35c46..6fa0d2fe49bb 100644
--- a/sys/netinet/in_pcb.c
+++ b/sys/netinet/in_pcb.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)in_pcb.c	8.4 (Berkeley) 5/24/95
- *	$Id: in_pcb.c,v 1.14 1995/10/29 15:32:25 phk Exp $
+ *	$Id: in_pcb.c,v 1.15 1995/11/14 20:33:59 phk Exp $
  */
 
 #include <sys/param.h>
@@ -46,6 +46,8 @@
 #include <sys/time.h>
 #include <sys/proc.h>
 #include <sys/queue.h>
+#include <sys/kernel.h>
+#include <sys/sysctl.h>
 
 #include <net/if.h>
 #include <net/route.h>
@@ -59,6 +61,18 @@
 
 struct	in_addr zeroin_addr;
 
+/*
+ * These configure the range of local port addresses assigned to
+ * "unspecified" outgoing connections/packets/whatever.
+ */
+static int ipport_firstauto = IPPORT_FIRSTAUTO;
+static int ipport_lastauto = IPPORT_LASTAUTO;
+
+SYSCTL_INT(_net_inet_ip, OID_AUTO, port_first_auto, CTLFLAG_RW,
+	   &ipport_firstauto, 0, "");
+SYSCTL_INT(_net_inet_ip, OID_AUTO, port_last_auto, CTLFLAG_RW,
+	   &ipport_lastauto, 0, "");
+
 static void	 in_pcbinshash __P((struct inpcb *));
 static void	 in_rtchange __P((struct inpcb *, int));
 
@@ -151,9 +165,9 @@ in_pcbbind(inp, nam)
 	if (lport == 0)
 		do {
 			++*lastport;
-			if (*lastport < IPPORT_RESERVED ||
-			    *lastport > IPPORT_USERRESERVED)
-				*lastport = IPPORT_RESERVED;
+			if (*lastport < ipport_firstauto ||
+			    *lastport > ipport_lastauto)
+				*lastport = ipport_firstauto;
 			lport = htons(*lastport);
 		} while (in_pcblookup(head,
 			    zeroin_addr, 0, inp->inp_laddr, lport, wild));