Changing timestamps in PCAP files

[JulianeFischer]

Thanks for introducing access to packet timestamps in Haka (0.2)!

Read access works perfectly fine, but unfortunately changing timestamps does not work for PCAP files.
Here is a minimum working example ("timestamp.lua"):

local raw = require('protocol/raw')

haka.rule{
    hook = raw.events.send_packet,
    eval = function(pkt)

    print("Before: " .. pkt.timestamp.secs)
    pkt.timestamp.secs = pkt.timestamp.secs + 1
    print("After: " .. pkt.timestamp.secs)
end
}

I run hakapcap on a very short PCAP ("testin.pcap"):

hakapcap --no-pass-through -o testout.pcap timestamp.lua testin.pcap

For every packet, I see two output lines, as intented:

Before: 1434009888
After: 1434009889

However, the output PCAP file ("testout.pcap") does not reflect the changes, as the timestamp remains unchanged. In fact, hashing "testin.pcap" and "testout.pcap" results in the same hash value.

[JulianeFischer]

Any comment?