пакетная выборка tc действие (packet sampling tc action)
Имя (Name)
sample - packet sampling tc action
Синопсис (Synopsis)
tc ... action sample rate RATE group GROUP [ trunc SIZE ] [ index
INDEX ]
tc ... action sample index INDEX
Описание (Description)
The sample action allows sampling packets matching classifier.
The packets are chosen randomly according to the rate parameter,
and are sampled using the psample generic netlink channel. The
user can also specify packet truncation to save user-kernel
traffic. Each sample includes some informative metadata about the
original packet, which is sent using netlink attributes,
alongside the original packet data.
The user can either specify the sample action parameters as
presented in the first form above, or use an existing sample
action using its index, as presented in the second form.
SAMPLED PACKETS METADATA FIELDS
The metadata are delivered to userspace applications using the
psample generic netlink channel, where each sample includes the
following netlink attributes:
PSAMPLE_ATTR_IIFINDEX
The input interface index of the packet, if there is one.
PSAMPLE_ATTR_OIFINDEX
The output interface index of the packet. This field is
not relevant on ingress sampling
PSAMPLE_ATTR_ORIGSIZE
The size of the original packet (before truncation)
PSAMPLE_ATTR_SAMPLE_GROUP
The psample group the packet was sent to
PSAMPLE_ATTR_GROUP_SEQ
A sequence number of the sampled packet. This number is
incremented with each sampled packet of the current
psample group
PSAMPLE_ATTR_SAMPLE_RATE
The rate the packet was sampled with
Параметры (Options)
rate RATE
The packet sample rate. RATE is the expected ratio
between observed packets and sampled packets. For example,
RATE of 100 will lead to an average of one sampled packet
out of every 100 observed.
trunc SIZE
Upon set, defines the maximum size of the sampled packets,
and causes truncation if needed
group GROUP
The psample group the packet will be sent to. The psample
module defines the concept of groups, which allows the
user to match specific sampled packets in the case of
multiple sampling rules, thus identify only the packets
that came from a specific rule.
index INDEX
Is a unique ID for an action. When creating new action
instance, this parameter allows to set the new action
index. When using existing action, this parameter allows
to specify the existing action index. The index must
32bit unsigned integer greater than zero.
Примеры (Examples)
Sample one of every 100 packets flowing into interface eth0 to
psample group 12:
tc qdisc add dev eth0 handle ffff: ingress
tc filter add dev eth0 parent ffff: matchall \
action sample rate 100 group 12 index 19
Use the same action instance to sample eth1 too:
tc qdisc add dev eth1 handle ffff: ingress
tc filter add dev eth1 parent ffff: matchall \
action sample index 19
Смотри также (See also)
tc(8), tc-matchall(8) psample(1)
