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Make the Man page reflect teh new reality.

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This commit is contained in:
Julian Elischer 1998-06-05 23:20:12 +00:00
parent e256a933a8
commit 9355ecfc52
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=36679
1 changed files with 21 additions and 17 deletions
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38
share/man/man4/divert.4
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@ -1,4 +1,4 @@
.\" $Id: divert.4,v 1.10 1998/03/12 07:30:16 charnier Exp $
.\" $Id: divert.4,v 1.11 1998/05/25 08:44:28 julian Exp $
.\"
.Dd June 18, 1996
.Dt DIVERT 4
@ -43,7 +43,8 @@ Diverted packets may be read unaltered via
or
.Xr recvfrom 2 .
In the latter case, the address returned will have its port set to
the divert port and the IP address set to the (first) address of
the some tag supplied by the packet diverter, (usually the ipfw rule number)
and the IP address set to the (first) address of
the interface on which the packet was received (if the packet
was incoming) or
.Dv INADDR_ANY
@ -83,23 +84,26 @@ packets, passing the same socket address supplied by
.Xr recvfrom 2
unmodified to
.Xr sendto 2
simplifies things.
simplifies things (see below).
.Pp
The port part of the socket address passed to the
.Xr sendto 2
contains a tag that should be meaningful to the diversion module. In the
case of
.Xr Ipfw 8
the tag is interpretted as the rule number
.Em after which
rule processing should restart.
.Sh LOOP AVOIDANCE
Packets written into a divert socket (using
.Xr sendto 2 )
are never rediverted back to the same socket. This means that a
given packet (either incoming or outgoing) will be diverted to a
given socket once and once only.
.Pp
.Xr Ipfw 8
rules are executed in order, each time the packet passes through
the kernel, but only up until a matching
.Nm
rule applies. On the second pass, after the packet has been diverted,
the divert rule is ignored and any subsequent
.Xr ipfw 8
rules are applied. For this reason, it is normally best to specify your
divert rules prior to any others.
.Xr sendto 2
) Re-enter the packet filter at the rule number
following the tag given in the port part of the socket address, which
is usually already set at the rule number that caused the diversion
(not the next rule if there are several at the same number). If the 'tag'
is altered to indicate an alternative re-entry point, care should be taken
to avoid loops, where the same packet is diverted more than once at the
same rule.
.Sh DETAILS
To enable divert sockets, your kernel must be compiled with the option
.Dv IPDIVERT .