[GTP] Incorrect destination TEID=0 (#3043) #3114
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
If eg. PCRF or AAA diameter link is not yet ready (eg. PCRF crashed), and a client sends a CreateSessionRequest announcing its ow F-TEID, then open5gs-smfd answers with Create Session Response Cause= "Remote peer not responding", but it is not setting the received F-TEID in the header of the response, instead it sends with TEI=0. As a result, the peer cannot match the CreateSessionResponse, and needs to rely on its own timeout timer to figure out that specific request failed. To address this issue, I modified the GTP Response message to check the Sender F-TEID and send it accordingly, setting the destination TEID to the value of the Sender F-TEID. I've made this modification only for SMF, but MME and SGW-C have not done so; if you need to, you can work from the examples in SMF. Similarly, the same situation can happen with PFCP. If anyone needs to do this in the future, I think you can work on it this way.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
If eg. PCRF or AAA diameter link is not yet ready (eg. PCRF crashed), and a client sends a CreateSessionRequest announcing its ow F-TEID, then open5gs-smfd answers with Create Session Response Cause= "Remote peer not responding", but it is not setting the received F-TEID in the header of the response, instead it sends with TEI=0.
As a result, the peer cannot match the CreateSessionResponse, and needs to rely on its own timeout timer to figure out that specific request failed.
To address this issue, I modified the GTP Response message to check the Sender F-TEID and send it accordingly, setting the destination TEID to the value of the Sender F-TEID.
I've made this modification only for SMF, but MME and SGW-C have not done so; if you need to, you can work from the examples in SMF.
Similarly, the same situation can happen with PFCP. If anyone needs to do this in the future, I think you can work on it this way.