Neels Janosch Hofmeyr 0d96ea1730 tunmap: always set GTP-U source port to 2152 when forwarding
We see GTP-U originating from ports other than 2152 in the field. When
osmo-upf forwards these, we want to forward from our GTP-U port 2152,
since that is the only port osmo-upf has bound for GTP-U (for echo).

According to 3GPP TS 29.060, the *destination* port for GTP-U shall be
2152 -- but the source port is apparently allowed to be different.

Before this patch, we would forward GTP-U like this:

  3.3.3.3:33333 -> (3.3.3.4:2152  UPF  2.2.2.2:33333) -> 1.1.1.1:2152
                                               ^^^^^

Instead we want to always send from UDP source port 2152:

  3.3.3.3:33333 -> (3.3.3.4:2152  UPF  2.2.2.2:2152) -> 1.1.1.1:2152
                                               ^^^^

This hasn't shown up before because so far all GTP-U peers we saw
consistently used source port 2152.

Related: SYS#6773
Change-Id: Idaf43f1c2b915846b50a8b97305f0229e34ad539
2024-05-08 17:09:52 +02:00
2024-04-15 16:38:45 +02:00
2023-03-18 01:33:05 +00:00
2022-08-24 16:10:56 +02:00

osmo-upf - Osmocom User Plane Function Implementation

Homepage

The official homepage of the project is https://osmocom.org/projects/osmo-upf/wiki

GIT Repository

You can clone from the official osmo-upf.git repository using

git clone https://gitea.osmocom.org/cellular-infrastructure/osmo-upf

There is a web interface at https://gitea.osmocom.org/cellular-infrastructure/osmo-upf.

To submit patches, see "Contributing" below.

Documentation

User Manuals and VTY reference manuals are [optionally] built in PDF form as part of the build process.

Pre-rendered PDF version of the current "master" can be found at User Manual as well as the VTY Reference Manual

Mailing List

Discussions related to osmo-bts are happening on the osmocom-net-gprs@lists.osmocom.org mailing list, please see https://lists.osmocom.org/postorius/lists/osmocom-net-gprs@lists.osmocom.org/ for subscription options and the list archive.

Please observe the Osmocom Mailing List Rules when posting.

Contributing

Our coding standards are described at https://osmocom.org/projects/cellular-infrastructure/wiki/Coding_standards

Submit patches at https://gerrit.osmocom.org/ See also https://osmocom.org/projects/cellular-infrastructure/wiki/Gerrit

The current patch queue for OsmoUPF can be seen at https://gerrit.osmocom.org/#/q/project:osmo-upf+status:open

Description
Osmocom implementationg of the 3GPP UPF (User Plane Function), an element with in the 4G Core Network
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