Extend nat/rdr syntax. Add source/destination selection. Make

interface optional. Suggested by rdump@river.com.
nat [on [!] <ifname>] from (any | [!] <addr>[/<mask>]) to (any |
[!] <addr>[/<mask>]) -> <addr> [proto (tcp | udp | icmp)]
rdr [on [!] <ifname>] from (any | [!] <addr>[/<mask>]) to (any |
[!] <addr>[/<mask>]) port <a>[:<b>] -> <addr> port <c>[:*]
[proto (tcp | udp | icmp)]

src/etc/nat.conf

@@ -1,4 +1,4 @@
-#	$OpenBSD: nat.conf,v 1.2 2001/06/26 22:58:31 smart Exp $
+#	$OpenBSD: nat.conf,v 1.3 2001/07/09 10:30:58 dhartmei Exp $
 #
 # See nat.conf(5) for syntax and examples
 #
@@ -9,10 +9,10 @@
 # translated as coming from 192.168.1.1. a state is created for such packets,
 # and incoming packets will be redirected to the internal address.
 
-# nat ext0 10.0.0.0/8 -> 192.168.1.1
+# nat on ext0 from 10.0.0.0/8 to any -> 192.168.1.1
 
 # rdr: packets coming in through ext0 with destination 192.168.1.1:1234 will
 # be redirected to 10.1.1.1:5678. a state is created for such packets, and
 # outgoing packets will be translated as coming from the external address.
 
-# rdr ext0 192.168.1.1/32 port 1234 -> 10.1.1.1 port 5678 proto tcp
+# rdr on ext0 from any to 192.168.1.1/32 port 1234 -> 10.1.1.1 port 5678 proto tcp