kern/177810: traffic dropped by accepting rules is not counted
vegeta at tuxpowered.net
Fri Apr 12 15:40:01 UTC 2013
>Synopsis: traffic dropped by accepting rules is not counted
>Arrival-Date: Fri Apr 12 15:40:00 UTC 2013
>Originator: Kajetan Staszkiewicz
FreeBSD xxxxxxx 9.1-RELEASE FreeBSD 9.1-RELEASE #10 r247265M: Mon Feb 25 14:58:39 CET 2013 root at xxxxxxx:/usr/obj/usr/src/sys/IGLB3 amd64
Currently per-rule counting is performed only for packets that are accepted by any rule or any packets matched by a droping rule. Counting on per-interface basis is perfomed properly.
There are some possibilities for a packet do be dropped by an accepting rule and therefore not counted:
1. SYN/SYN+ACK/ACK packets going through synproxy are dropped with PF_SYNPROXY_DROP action. This generates new packets sent to client and server that are legitimate traffic and should be counted.
2. Creation of a state or a src-node might fail due to memory or per-rule state limits. This traffic is dropped (or at least should be, have a look on kern/177808), but still matched some rule. I believe it also should be counted, but this is open for discussion.
SYN-flood your FreeBSD based machine with synproxy rules or rules with state limit, observe no increase of counters of `pfctl -sl`
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