 | 1 | initial version |
The offset is due to the headers provided by the other parts of the frame, i.e. the Ethernet, IP and UDP headers. Note that by passing the 4th parameter to proto_tree_add_uint() as 1 you're asking for the byte at offset 1 in your tvb, i.e. the second byte in the UDP payload.
Presumably you have registered your dissector with the UDP dissector, hence the preceding items. The byte view shows the whole frame not just your application data.
It's not clear to me why you expect the result to be 0x00, which byte in the byte view are you expecting to read?
