Ipfw processing of frames at layer 2 can be enabled by the sysctl variable
net.link.ether.ipfw=1
Consider this feature experimental, because right now, the firewall
is invoked in the places indicated below, and controlled by the
sysctl variables listed on the right. As a consequence, a packet
can be filtered from 1 to 4 times depending on the path it follows,
which might make a ruleset a bit hard to follow.
I will add an ipfw option to tell if we want a given rule to apply
to ether_demux() and ether_output_frame(), but we have run out of
flags in the struct ip_fw so i need to think a bit on how to implement
this.
to upper layers
| |
+----------->-----------+
^ V
[ip_input] [ip_output] net.inet.ip.fw.enable=1
| |
^ V
[ether_demux] [ether_output_frame] net.link.ether.ipfw=1
| |
+->- [bdg_forward]-->---+ net.link.ether.bridge_ipfw=1
^ V
| |
to devices
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