.TH "Generic actions in tc" 8 "11 Jan 2023" "iproute2" "Linux"

.SH NAME
gact - generic action
.SH SYNOPSIS
.in +8
.ti -8
.BR tc " ... " "action gact"
.IR CONTROL " [ " RAND " ] [ " INDEX " ]"
.ti -8
.IR CONTROL " := { "
.BR reclassify " | " drop " | " continue " | " pass " | " pipe " | "
.br
.BI "goto chain " "CHAIN_INDEX"
|
.br
.BI "jump " "JUMP_COUNT"
}

.ti -8
.IR RAND " := "
.BI random " RANDTYPE CONTROL VAL"
.ti -8
.IR RANDTYPE " := { "
.BR netrand " | " determ " }"
.ti -8
.IR VAL " := number not exceeding 10000"
.ti -8
.IR JUMP_COUNT " := absolute jump from start of action list"
.ti -8
.IR INDEX " := index value used"

.SH DESCRIPTION
The
.B gact
action allows reclassify, dropping, passing, or accepting packets.
At the moment there are only two algorithms. One is deterministic
and the other uses internal kernel netrand.

.SH OPTIONS
.TP
.BI random " RANDTYPE CONTROL VAL"
The probability of taking the action expressed in terms of 1 out of
.I VAL
packets.

.TP
.I CONTROL
Indicate how
.B tc
should proceed if the packet matches.
For a description of the possible
.I CONTROL
values, see
.BR tc-actions (8).

.SH EXAMPLES
Apply a rule on ingress to drop packets from a given source address.
.RS
.EX
# tc filter add dev eth0 parent ffff: protocol ip prio 6 u32 match ip src \
10.0.0.9/32 flowid 1:16 action drop
.EE
.RE

Allow 1 out 10 packets from source randomly using the netrand generator
.RS
.EX
# tc filter add dev eth0 parent ffff: protocol ip prio 6 u32 match ip src \
10.0.0.9/32 flowid 1:16 action drop random netrand ok 10
.EE
.RE

Deterministically accept every second packet
.RS
.EX
# tc filter add dev eth0 parent ffff: protocol ip prio 6 u32 match ip src \
10.0.0.9/32 flowid 1:16 action drop random determ ok 2
.EE
.RE

.SH SEE ALSO
.BR tc (8),
.BR tc-actions (8),
.BR tc-u32 (8)