Cellular Network Infrastructure » Core Network (CN) » OsmoDia2GSUP

Attached is a pcap with four packets (order by time, not no.):
1. (no. 4) Synchronization failure from the eNodeb/UE that includes the AUTS value
1. (no. 1) AIR from the MME to the HSS (osmo-dia2gsup) including the Re-Synchronization-Info
1. (no. 2) SendAuthInfo Request from osmo-dia2gsup to osmo-hlr without either the AUTS or RAND IEs

Here's what osmo-dia2gsup reports for 2. (packet no.1):

Aug 16 15:01:56 sysmonitb osmo-dia2gsup[668]: 15:01:56.234 [info] AIR: {'AIR',"mme.localdomain;1660658436;38;app_s6a",1,"mme.localdomain","localdomain","localdomain",
"901700000043352",[153,249,7],[{'Vendor-Specific-Application-Id',10415,[16777251],[]}],[],
[{'Requested-EUTRAN-Authentication-Info',[1],[1],[[154,153,78,226,63,248,178,208,169,186,215,18,159,150,252,103,249,220,169,90,223,249,219,26,172,118,171,193,216,221]],
[]}],[],[],[],[],[]}
Aug 16 15:01:56 sysmonitb osmo-dia2gsup[668]: 15:01:56.234 [info] Num EUTRAN=1, UTRAN=false

There is code in server_cb.erl (around line. 191) to include rand and auts if #'Requested-EUTRAN-Authentication-Info'{'Re-Synchronization-Info' = ReSyncInfo}, but it seems to me that the data in 'Requested-EUTRAN-Authentication-Info' isn't actually decoded.

If I look at the [1],[1],[[154,153,...]] this seems to match what Wireshark is telling me about the Requested-EUTRAN-Authentication-Info:

Number-Of-Requested-Vectors:1, Immediate-Response-Preferred:1, Re-Synchronization-Info: 0x9a(154), 0x99(153), ...