libgtp5gnl - netlink library for Linux kernel module 5G GTP-U

In order to control the kernel-side GTP-U plane, a netlink based control interface between GTP-C in userspace and GTP-U in kernelspace was invented.

The encoding and decoding of these control messages is implemented in the libgtp5gnl (library for GTP netlink).

libgtp5gnl is a project based on libgtpnl which is part of the Osmocom Open Source Mobile Communications project.

Usage

Compile

autoreconf -iv
./configure --prefix=`pwd`
make

Command

Sample command is written under script/ and tools/gtp5g-tunnel.c.

Show Current Rules

sudo ./tools/gtp5g-tunnel list pdr
sudo ./tools/gtp5g-tunnel list far
sudo ./tools/gtp5g-tunnel list qer

get/del/add/mod PDR/FAR/QER

sudo ./gtp5g-tunnel [get/del/add/mod] [PDR/FAR/QER] [interface_name] [seid] [id] [option]
e.g.  sudo ./gtp5g-tunnel add pdr upfgtp 0 1 --pcd 99

PDR OPTIONS

        --pcd <precedence>

        --hdr-rm <outer-header-removal>

        --far-id <existed-far-id>

        --ue-ipv4 <pdi-ue-ipv4>

        --f-teid <i-teid> <local-gtpu-ipv4>

        --sdf-desp <description-string>

                ex: --sdf-desp 'permit out ip from 192.168.0.1 22,53,73 to 127.0.0.1/24'

        --sdf-tos-traff-cls <tos-traffic-class>

        --sdf-scy-param-idx <security-param-idx>

        --sdf-flow-label <flow-label>

        --sdf-id <id>

        --qer-id <id>

FAR OPTIONS

        --action <apply-action>

        --hdr-creation <description> <o-teid> <peer-ipv4> <peer-port>

        --fwd-policy <mark set in iptable>

                Set mark into packet and exec Linux routing>

QER OPTIONS

        --qer-id <qer-id>

        --qfi-id <qfi-id> [Value range: {0..63}]

        --rqi-d <rqi> [Value range: {0=not triggered, 1=triggered}]

        --ppp <ppp> [Value range: {0=not present, 1=present}]

        --ppi <ppi> [Value range: {0..7}]

Test

Simple Test (RAN + UPF)

./run.sh SimpleUPTest

ULCL Test (RAN + I-UPF + A-UPF)

./run.sh ULCLTest1

Change Log

v0.2.0

Changed to host type between gtp5g and libgtp5gnl
Supported forwarding policy feature, but need to set ip rule and ip route with Linux mark by self
Fixed bugs about "any" and "assigned" in SDF filter
Fixed bugs about netmask translation between gtp5g and libgtp5gnl in SDF filter

v0.1.0

First version
Supported packet matching about UE IP, TEID and SDF filter

free5gc / libgtp5gnl