I'm trying to create a TCP packet with POX controller and sending it to one of the switches.
This is how the packet is created:
payload = "MESSAGE"
tcp_packet = tcp()
tcp_packet.srcport = 10000
tcp_packet.dstport = 10001
tcp_packet.payload = payload
tcp_packet.seq = 100
ipv4_packet = ipv4()
ipv4_packet.iplen = ipv4.MIN_LEN + len(tcp_packet)
ipv4_packet.protocol = ipv4.TCP_PROTOCOL
ipv4_packet.dstip = IPAddr('10.0.0.5')
ipv4_packet.srcip = IPAddr('10.0.0.1')
ipv4_packet.set_payload(tcp_packet)
eth_packet = ethernet()
eth_packet.set_payload(ipv4_packet)
eth_packet.dst = EthAddr('00:00:00:00:00:05')
eth_packet.src = EthAddr('00:00:00:00:00:01')
eth_packet.type = ethernet.IP_TYPE
Afterwards, it's sent through one of the ports of a switch. When I try to capture the packet in PacketIn handler:
event.parsed.find('tcp')
returns None, as though there's no TCP packet. Capturing the traffic with Wireshark, I see the packet (wrapped in OF packet) but Wireshark warns that TCP header is zero.
Is this indeed the problem, with the header, and if it's how can I fix this ?
Thank you
The problem was that data offset field had not been set. Since, the minimal header length for TCP packet is 5 32bit words (20 bytes) and I've no options set in the header. So in order to fix this, I should had to add:
tcp_packet.off = 5
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