cvs commit: src/sys/netinet ip_fw.h ip_fw2.c src/sbin/ipfw ipfw.8 ipfw2.c

Andrey V. Elsukov bu7cher at
Wed May 24 09:47:02 PDT 2006

>Does this accept the packet and untag it at the same time?  Wouldn't
>it make more sense to have [tag|untag] as its own operators like

Yes, it does (but example is impractical - we don't need tagging or untagging when packet is finally denied). We thought about making [tag|untag] as its own actions like [allow|deny], but decided to implement it as modifiers instead, for two primary reasons:

1) Speed. It is faster to match packet with body of only one rule than to do it once more for the same packet in the next rule, only to take action on it.

2) Flexibility. We can use modifiers tag/untag with any possible actions, e.g. allow, netgraph, skipto, pipe, ... - not only [allow|deny]. Imagine you have to insert additional tagging rule for any such action looking absolutely the same? And then consider speed of matching. Thus, it is even *looks* more beautiful to write:

   ipfw add 100 netgraph 300 tag 200 ip from host1 to host2

for tagging packet with tag 200 and then sending it to netgraph, than to write something like:

   ipfw add 100 tag 200 ip from host1 to host2
   ipfw add 101 netgraph 300 ip from host1 to host2 tagged 200

WBR, Andrey V. Elsukov

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