npf-params(7) - NetBSD Manual Pages

NPF-PARAMS(7)       NetBSD Miscellaneous Information Manual      NPF-PARAMS(7)


NAME

     npf-params -- tunable NPF parameters


DESCRIPTION

     NPF supports a set of dynamically tunable parameters.

     All parameter values are integers and should generally be between zero
     and INT_MAX, unless specified otherwise.  Some parameters values can be
     negative; such values would typically have a special meaning.
     Enable/disable switches should be represented as boolean values 0 ("off")
     or 1 ("on").


PARAMETERS

     bpf.jit
             BPF just-in-time compilation: enables or disables bpfjit(4) sup-
             port.  Some machine architectures are not presently supported by
             bpfjit(4).  Setting this parameter to off stops NPF from trying
             to enable this functionality, and generating a warning if it is
             unable to do so.  Default: 1.

     ip4.reassembly
             Perform IPv4 reassembly before inspecting the packet.  Fragmenta-
             tion is considered very harmful, so most networks are expected to
             prevent it; therefore, reassembly is disabled by default.  How-
             ever, while the packet should generally be reassembled at the
             receiver, reassembly by the packet filter might be necessary in
             order to perform state tracking.  Default: 0.

     ip6.reassembly
             Perform IPv6 reassembly before inspecting the packet.  Discour-
             aged in general but not prohibited by RFC 8200.  Default: 0.

     gc.step
             Number of connection state items to process in one garbage col-
             lection (G/C) cycle.  Must be positive number.  Default: 256.

     gc.interval_min
             The lower bound for the sleep time of the G/C worker.  The worker
             is self-tuning and will wake up more frequently if there are con-
             nections to expire; it will wake up less frequently, diverging
             towards the upper bound, if it does not encounter expired connec-
             tions.  Default: 50 (in milliseconds).

     gc.interval_min
             The upper bound for the sleep time of the G/C worker.  Default:
             5000 (in milliseconds).

     state.key
             The connection state is uniquely identified by an n-tuple.  The
             state behavior can be controlled by including (excluding) some of
             the information in (from) the keys.

             interface
                     Include interface identifier into the keys, making the
                     connection state strictly per-interface.  Default: 1.

             direction
                     Include packet direction into the keys.  Default: 1.

     state.generic
             Generic state tracking parameters for non-TCP flows.  All time-
             outs are in seconds and must be zero or positive.

             timeout.new
                     Timeout for new ("unsynchronized") state.  Default: 30.

             timeout.established
                     Timeout for established ("synchronized") state.  Default:
                     60.

             timeout.closed
                     Timeout for closed state.  Default: 0.

     state.tcp
             State tracking parameters for TCP connections.  All timeout val-
             ues are in seconds.

             max_ack_win
                     Maximum allowed ACK window.  Default: 66000.

             strict_order_rst
                     Enforce strict order RST.  Default: 1.

             timeout.new
                     Timeout for a new connection in "unsynchronized" state.
                     Default: 30.

             timeout.established
                     Timeout for an established connection ("synchronized"
                     state).  Default: 86400.

             timeout.half_close
                     Timeout for the half-close TCP states.  Default: 3600.

             timeout.close
                     Timeout for the full close TCP states.  Default: 10.

             timeout.time_wait
                     Timeout for the TCP time-wait state.  Default: 240.

     portmap.min_port
             Lower bound of the port range used when selecting the port for
             dynamic NAT with port translation enabled.  Default: 1024 (inclu-
             sive; also the lowest allowed value).

     portmap.max_port
             Upper bound of the port range as described above.  Default: 49151
             (inclusive; 65535 is the highest allowed value).


EXAMPLES

     An example line in the npf.conf(5) configuration file:

           set state.tcp.strict_order_rst on       # "on" can be used instead of 1
           set state.tcp.timeout.time_wait 0       # destroy the state immediately


SEE ALSO

     libnpf(3), npfkern(3), bpfjit(4), npf.conf(5), pcap-filter(7), npfctl(8)


AUTHORS

     NPF was designed and implemented by Mindaugas Rasiukevicius.

NetBSD 9.3                       May 31, 2020                       NetBSD 9.3