How to check for presence of a layer in a scapy packet?

For completion I thought I would also mention the haslayer method.

>>> pkts=rdpcap("rogue_ospf_hello.pcap") 
>>> p=pkts[0]
>>> p.haslayer(UDP)
0
>>> p.haslayer(IP)
1

Hope that helps as well.

You should try the in operator. It returns True or False depending if the layer is present or not in the Packet.

root@u1010:~/scapy# scapy
Welcome to Scapy (2.2.0-dev)
>>> load_contrib("ospf")
>>> pkts=rdpcap("rogue_ospf_hello.pcap")
>>> p=pkts[0]
>>> IP in p
True
>>> UDP in p
False
>>>
root@u1010:~/scapy#