Adding GSMTAP LTE RRC Channel name mapping
Wireshark
infostam Pte. Ltd.
Last Update 5 maanden geleden
In dissect_gsmtap_v2 the channel_str does not really consider the different GSM TAP types.
This means that the channel value shown in the proto tree does not match with the actual (correct) sub-type of the particular GSM TAP type.
What is the current bug behavior?
Beside GSMTAP_TYPE_TETRA_I1 and GSMTAP_TYPE_GMR1_UM there is nothing more except the default (else statement) which is GSMTAP_TYPE_UM.
The current gsmtap_channels array considers the sub-types for TYPE_UM only. And it is not valid (correct) for other types.
Currently: GSM TAP Header, ARFCN: 0 (Downlink), TS: 0, Channel: PCH (0) for an LTE RRC BCCH-DL-SCH-Message.
What is the expected correct behavior?
The Channel string should relate to the GSMTAP_TYPE.
For example, in case of GSMTAP_TYPE_LTE_RRC when sub-type is 0x05, the proto tree should have:
GSM TAP Header, ARFCN: 0 (Downlink), TS: 0, Channel: BCCH (0)
The lte_rrc_sub_handles is correctly defined, this is used for calling the proper dissector for the GSMTAP payload.
Based on that, we could create a new gsmtap_lte_rrc_channels for a correct channel interpretation (and similar for other GSMTAP_TYPE_* accordingly).
Links: Issue #20236 and Merge request #18217