2.4. spp_pcap¶
spp_pcap is a kind of SPP secondary process. It it introduced for
providing packet capture features.
Each of spp_pcap processes is managed with pcap command. It is for
sending sub commands with specific ID called secondary ID for starting or
stopping packet capture.
Secondary ID is referred as --client-id which is given as an argument
while launching spp_pcap. It should be unique among all of secondary
processes including spp_nfv, spp_vm and others.
pcap command takes an secondary ID and one of sub commands. Secondary ID
and sub command should be separated with delimiter ;, or failed to a
command error.
spp > pcap SEC_ID; SUB_CMD
In this example, SEC_ID is a secondary ID and SUB_CMD is one of the
following sub commands. Details of each of sub commands are described in the
next sections.
- status
- start
- stop
- exit
spp_pcap supports TAB completion. You can complete all of the name
of commands and its arguments. For instance, you find all of sub commands
by pressing TAB after pcap SEC_ID;.
spp > pcap 1; # press TAB key
exit start status stop
It tries to complete all of possible arguments.
spp > pcap 1; component st # press TAB key to show args starting 'st'
start status stop
If you are reached to the end of arguments, no candidate keyword is displayed.
It is a completed statement of start command, and TAB
completion does not work after start because it is ready to run.
spp > pcap 1; start
Succeeded to start capture
It is also completed secondary IDs of spp_pcap and it is helpful if you
run several spp_pcap processes.
spp > pcap # press TAB after space following 'pcap'
1; 3; # you find two spp_pcap processes of sec ID 1, 3
By the way, it is also a case of no candidate keyword is displayed if your command statement is wrong. You might be encountered an error if you run the wrong command. Please take care.
spp > pcap 1; ste # no candidate shown for wrong command
Invalid command "ste".
2.4.1. status¶
Show the information of worker threads of receiver and writer threads
and its resources.
spp > pcap 1; status
Basic Information:
- client-id: 1
- status: idling
- lcore_ids:
- master: 1
- slaves: [2, 3, 4, 5, 6]
Components:
- core:2 receive
- rx: phy:0
- core:3 write
- filename:
- core:4 write
- filename:
- core:5 write
- filename:
- core:6 write
- filename:
client-id is a secondary ID of the process and status shows
running status.
Each of lcore has a role of receive or write.
receiver has capture port as input and write has a capture file
as output, but the filename is empty while idling status
because capturing is not started yet.
If you start capturing, you can find each of writer threads has a
capture file. After capturing is stopped, filename is returned to
be empty again.
spp > pcap 2; status
- client-id: 2
- status: running
- core:2 receive
- rx: phy:0
- core:3 write
- filename: /tmp/spp_pcap.20190214161550.phy0.1.1.pcap.lz4
- core:4 write
- filename: /tmp/spp_pcap.20190214161550.phy0.2.1.pcap.lz4
- core:5 write
- filename: /tmp/spp_pcap.20190214161550.phy0.3.1.pcap.lz4
- core:6 write
- filename: /tmp/spp_pcap.20190214161550.phy0.4.1.pcap.lz4
2.4.2. start¶
Start packet capture.
# start capture
spp > pcap SEC_ID; start
Here is a example of starting capture.
# start capture
spp > pcap 1; start
Start packet capture.
2.4.3. stop¶
Stop packet capture.
# stop capture
spp > pcap SEC_ID; stop
Here is a example of stopping capture.
# stop capture
spp > pcap 2; stop
Start packet capture.