Extract email addresses from pcap file with dpkt

Question

I'm new to python and I'm trying to write a script that will open and parse a pcap file. I have managed to do that but now I need to extract email addresses present in the fields To: and From: included in the packets and then print them. I have been using wireshark on the side to check where the email addresses where but I just can't find how to extract them. What I know so far is that I can find when looking for smtp or tcp.dstport == 587 but I don't know how to use that in python. Any help would be apreciated

Below you can find the code I have to parse the file

import dpkt

pcapfile = 'test.pcap'
f = open(pcapfile, 'rb')
pcap = dpkt.pcap.Reader(f)

for ts,buf in pcap:
    eth=dpkt.ethernet.Ethernet(buf)
    ip=eth.data
    tcp=ip.data
    

    print(repr(tcp))
    break