144 lines
4.5 KiB
Groff
144 lines
4.5 KiB
Groff
.\" Copyright (c) 2015 Dmitry Vagin <daemon.hammer@ya.ru>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd October 29, 2015
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.Dt NG_CHECKSUM 4
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.Os
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.Sh NAME
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.Nm ng_checksum
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.Nd reconstructing IP checksums node type
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.Sh SYNOPSIS
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.In netgraph/ng_checksum.h
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.Sh DESCRIPTION
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The
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.Nm checksum
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node can calculate, or prepare for calculation in hardware,
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IPv4 header, TCP and UDP checksums.
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.Sh HOOKS
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This node type has two hooks:
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.Bl -tag -width ".Va out"
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.It Va in
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Packets received on this hook are processed according to settings specified
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in config and then forwarded to the
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.Ar out
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hook, if it exists and is connected. Otherwise they are reflected back to the
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.Ar in
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hook.
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.It Va out
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Packets received on this hook are forwarded to the
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.Ar in
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hook without any changes.
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.El
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.Sh CONTROL MESSAGES
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This node type supports the generic control messages, plus the following:
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.Bl -tag -width foo
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.It Dv NGM_CHECKSUM_SETDLT Pq Ic setdlt
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Sets the data link type on the
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.Va in
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hook. Currently, supported types are
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.Cm DLT_RAW
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(raw IP datagrams) and
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.Cm DLT_EN10MB
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(Ethernet). DLT_ definitions can be found in the
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.In net/bpf.h
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header. Currently used values are
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.Cm DLT_EN10MB
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= 1 and
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.Cm DLT_RAW
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= 12.
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.It Dv NGM_CHECKSUM_GETDLT Pq Ic getdlt
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This control message obtains the data link type on the
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.Va in
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hook.
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.It Dv NGM_CHECKSUM_SETCONFIG Pq Ic setconfig
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Sets the node configuration. The following
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.Vt "struct ng_checksum_config"
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must be supplied as an argument:
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.Bd -literal -offset 4n
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struct ng_checksum_config {
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uint64_t csum_flags;
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uint64_t csum_offload;
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};
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.Ed
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.Pp
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The
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.Va csum_flags
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can be set to any combination of CSUM_IP, CSUM_TCP, CSUM_UDP, CSUM_TCP_IPV6 and CSUM_UDP_IPV6
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(other values are ignored) for instructing the node to calculate the corresponding checksum.
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.Pp
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The
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.Va csum_offload
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value can be set to any combination of CSUM_IP, CSUM_TCP, CSUM_UDP, CSUM_TCP_IPV6 and CSUM_UDP_IPV6
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(other values are ignored) for instructing the node what checksums should be requested from the hardware.
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.Pp
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The node also takes into account any combination of
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CSUM_IP, CSUM_TCP, CSUM_UDP, CSUM_TCP_IPV6 and CSUM_UDP_IPV6 already
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flagged on the mbuf.
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.It Dv NGM_CHECKSUM_GETCONFIG Pq Ic getconfig
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This control message obtains the current node configuration returned as a
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.Vt "struct ng_checksum_config" .
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.It Dv NGM_CHECKSUM_GET_STATS Pq Ic getstats
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Returns node statistics as a
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.Vt "struct ng_checksum_stats" .
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.It Dv NGM_CHECKSUM_CLR_STATS Pq Ic clrstats
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Clear the node statistics.
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.It Dv NGM_CHECKSUM_GETCLR_STATS Pq Ic getclrstats
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This command is identical to
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.Dv NGM_CHECKSUM_GET_STATS ,
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except that the statistics are also atomically cleared.
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.El
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.Sh SHUTDOWN
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This node shuts down upon receipt of a
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.Dv NGM_SHUTDOWN
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control message, or when all hooks have been disconnected.
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.Sh EXAMPLES
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.Xr ngctl 8
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script:
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.Bd -literal -offset 4n
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/usr/sbin/ngctl -f- <<-SEQ
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msg checksum-1: setdlt 1
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msg checksum-1: setconfig { csum_flags=0 csum_offload=6 }
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SEQ
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.Ed
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.Pp
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Set the data link type to
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.Cm DLT_EN10MB
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(Ethernet), do not set additional checksum flags
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and request that the hardware calculate CSUM_IP_UDP|CSUM_IP_TCP.
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.Sh SEE ALSO
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.Xr netgraph 4 ,
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.Xr ng_patch 4 ,
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.Xr ngctl 8
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.Sh HISTORY
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The
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.Nm
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node type was implemented in
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.Fx 10.2
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and first submitted in
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.Fx 12.0 .
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.Sh AUTHORS
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.An "Dmitry Vagin" Aq daemon.hammer@ya.ru .
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