forked from acouzens/open5gs
3886891833
A race condition can occur in the following situations. In conclusion, we can use this situation to determine whether or not the UE Context has been removed and avoiding a crash. For example, suppose a UE Context is removed in the followings. 1. Attach Request 2. Authentication-Information-Request 3. Authentication-Information-Answer 4. Authentication Request 5. Authentication Response(MAC Failed) 6. Authentication Reject 7. UEContextReleaseCommand 8. UEContextReleaseComplete The MME then sends a Purge-UE-request to the HSS and deletes the UE context as soon as it receives a Purge-UE-Answer. Suppose an Attach Request is received from the same UE between Purge-UE-Request/Answer, then the MME and HSS start the Authentication-Information-Request/Answer process. This can lead to the following situations. 1. Purge-UE-Request 2. Attach Request 3. Authentication-Information-Request 4. Purge-UE-Answer 5. [UE Context Removed] 6. Authentication-Information-Answer Since the UE Context has already been deleted when the Authentication-Information-Answer is received, it cannot be processed properly. Therefore, mme_ue_cycle() is used to check whether the UE Context has been deleted and decide whether to process or ignore the Authentication-Information-Answer as shown below. |
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| app | ||
| asn1c | ||
| core | ||
| crypt | ||
| dbi | ||
| diameter | ||
| gtp | ||
| ipfw | ||
| metrics | ||
| nas | ||
| ngap | ||
| pfcp | ||
| proto | ||
| s1ap | ||
| sbi | ||
| sctp | ||
| tun | ||
| meson.build | ||