handling of reserved bit in flag octet broken
When we receive a GTP1U message whose processing fails for some reason (e.g. unknown TEID), we send an error message in response. This error message is generated by gtp_error_ind_resp() which unconditionall uses get_seq() to determine the sequence number. However, GTP-U packets don't have sequence numbers, and thus an error message like "Unknown packet flags: 56" is printed.
This is misleading, as the respective flags without a sequence number is perfectly legal for GTP1U, but not GTP1C