o Remove entire section talking about RTF_PRCLONING that got nuked in 5.2

  already.
o Better description of IP fastforwarding.  It can do the full thing now
  including firewalling.
o Reword the description of ICMP redirects.
o Add references to route(4) and pfil(9).

1 files changed, 25 insertions, 76 deletions

diff --git a/share/man/man4/inet.4 b/share/man/man4/inet.4
index a8e9c876f2f7..93e2a1b01108 100644
--- a/share/man/man4/inet.4
+++ b/share/man/man4/inet.4
@@ -32,7 +32,7 @@
 .\"     From: @(#)inet.4	8.1 (Berkeley) 6/5/93
 .\" $FreeBSD$
 .\"
-.Dd August 15, 2004
+.Dd October 23, 2004
 .Dt INET 4
 .Os
 .Sh NAME
@@ -151,69 +151,6 @@ then subnets are in use.
 .It Dv SIOCGIFNETMASK
 Get interface network mask.
 .El
-.Sh ROUTING
-The current implementation of Internet protocols includes some routing-table
-adaptations to provide enhanced caching of certain end-to-end
-information necessary for Transaction TCP and Path MTU Discovery.
-The
-following changes are the most significant:
-.Bl -enum
-.It
-All IP routes, except those with the
-.Dv RTF_CLONING
-flag and those to multicast destinations, have the
-.Dv RTF_PRCLONING
-flag forcibly enabled (they are thus said to be
-.Dq "protocol cloning" ) .
-.It
-When the last reference to an IP route is dropped, the route is
-examined to determine if it was created by cloning such a route.
-If this is the case, the
-.Dv RTF_PROTO3
-flag is turned on, and the expiration timer is initialized to go off
-in net.inet.ip.rtexpire seconds.
-If such a route is re-referenced,
-the flag and expiration timer are reset.
-.It
-A kernel timeout runs once every ten minutes, or sooner if there are
-soon-to-expire routes in the kernel routing table, and deletes the
-expired routes.
-.El
-.Pp
-A dynamic process is in place to modify the value of
-net.inet.ip.rtexpire if the number of cached routes grows too large.
-If after an expiration run there are still more than
-net.inet.ip.rtmaxcache unreferenced routes remaining, the rtexpire
-value is multiplied by 3/4, and any routes which have longer
-expiration times have those times adjusted.
-This process is damped somewhat by specification of a minimum rtexpire value
-(net.inet.ip.rtminexpire), and by restricting the reduction to once in
-a ten-minute period.
-.Pp
-If some external process deletes the original route from which a
-protocol-cloned route was generated, the
-.Dq child route
-is deleted.
-(This is actually a generic mechanism in the routing code support for
-protocol-requested cloning.)
-.Pp
-No attempt is made to manage routes which were not created by protocol
-cloning; these are assumed to be static, under the management of an
-external routing process, or under the management of a link layer
-(e.g.,
-.Tn ARP
-for Ethernets).
-.Pp
-Only certain types of network activity will result in the cloning of a
-route using this mechanism.
-Specifically, those protocols (such as
-.Tn TCP
-and
-.Tn UDP )
-which themselves cache a long-lasting reference to route for a destination
-will trigger the mechanism; whereas raw
-.Tn IP
-packets, whether locally-generated or forwarded, will not.
 .Ss MIB Variables
 A number of variables are implemented in the net.inet branch of the
 .Xr sysctl 3
@@ -228,22 +165,32 @@ Boolean: enable/disable forwarding of IP packets.
 Defaults to off.
 .It Dv IPCTL_FASTFORWARDING
 .Pq ip.fastforwarding
-Boolean: enable/disable the use of fast IP forwarding code.
+Boolean: enable/disable the use of
+.Tn fast IP forwarding
+code.
 Defaults to off.
-When fast forwarding is enabled, IP packets are forwarded directly to
-the appropriate network interface with a minimal validity checking, which
-greatly improves the throughput.
-On the other hand, they bypass the
-standard procedures, such as IP option processing and
-.Xr ipfirewall 4
-checking.
-It is not guaranteed that every packet will be fast-forwarded.
+When
+.Tn fast IP forwarding
+is enabled, IP packets are forwarded directly to the appropriate network
+interface with direct processing to completion, which greatly improves
+the throughput.
+All packets for local IP addresses, non-unicast, or with IP options are
+handled by the normal IP input processing path.
+All features of the normal (slow) IP forwarding path are supported
+including firewall (through
+.Xr pfil 9
+hooks) checking, except
+.Xr IPSEC 4
+tunnel brokering.
+The
+.Tn IP fastforwarding
+path does not generate ICMP redirect or source quench messages.
 .It Dv IPCTL_SENDREDIRECTS
 .Pq ip.redirect
 Boolean: enable/disable sending of ICMP redirects in response to
-unforwardable
 .Tn IP
-packets.
+packets for which a better, and for the sender directly reachable, route
+and next hop is known.
 Defaults to on.
 .It Dv IPCTL_DEFTTL
 .Pq ip.ttl
@@ -310,9 +257,11 @@ IPv6 flow IDs and fragment IDs are always random.
 .Xr intro 4 ,
 .Xr ip 4 ,
 .Xr ipfirewall 4 ,
+.Xr route 4 ,
 .Xr tcp 4 ,
 .Xr ttcp 4 ,
-.Xr udp 4
+.Xr udp 4,
+.Xr pfil 9
 .Rs
 .%T "An Introductory 4.3 BSD Interprocess Communication Tutorial"
 .%B PS1