Prevent tcpreplay blocking Mininet Python API cmds

Question

I need to execute multiple different commands to replay pcaps into my network.

The first pcap is over 100 seconds, I need to play it and then immediately play other pcaps.

My problem is, when I execute this line in my python code:

h2.cmd('tcpreplay --intf1=h2-eth0 BenignTest.pcap 10.0.0.1')

The program waits for this 100 second pcap to finish before continuing. I need the program to continue as soon as it sends that command.

Is there a way to make tcpreplay non-blocking like this?

score 0 · Accepted Answer · answered Feb 20 '19 at 14:51

Turns out it is as simple as adding & to the end of the command.

h2.cmd('tcpreplay --intf1=h2-eth0 BenignTest.pcap 10.0.0.1 &')

& sends the command to the background and frees up the terminal being used.

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