Not found 2152/udp bound to GTP-U for N3 interface

[s5uishida]

Hi,

For example, when I created the config.yml below and run bin/eupf, the bind port of 2152/udp was not found by ss command.

config.yml

interface_name: [enp0s10, enp0s16]
xdp_attach_mode: generic
api_address: :8080
pfcp_address: 192.168.14.151:8805
pfcp_node_id: 192.168.14.151
metrics_address: :9090
n3_address: 192.168.13.151
qer_map_size: 1024
far_map_size: 1024
pdr_map_size: 1024
logging_level: info

I tried getting the log again. Sorry.

# bin/eupf --config config.yml
2023/10/15 06:16:41 Get raw config: map[api_address::8080 far_map_size:1024 heartbeat_interval:5 heartbeat_retries:3 heartbeat_timeout:5 interface_name:[enp0s10 enp0s16] logging_level:info metrics_address::9090 n3_address:192.168.13.151 pdr_map_size:1024 pfcp_address:192.168.14.151:8805 pfcp_node_id:192.168.14.151 qer_map_size:1024 resize_ebpf_maps:false xdp_attach_mode:generic]
2023/10/15 06:16:41 Apply eUPF config: {InterfaceName:[enp0s10 enp0s16] XDPAttachMode:generic ApiAddress::8080 PfcpAddress:192.168.14.151:8805 PfcpNodeId:192.168.14.151 MetricsAddress::9090 N3Address:192.168.13.151 QerMapSize:1024 FarMapSize:1024 PdrMapSize:1024 EbpfMapResize:false HeartbeatRetries:3 HeartbeatInterval:5 HeartbeatTimeout:5 LoggingLevel:info}
2023/10/15 06:16:41 INF Attached XDP program to iface "enp0s10" (index 5)
2023/10/15 06:16:41 INF Attached XDP program to iface "enp0s16" (index 6)
2023/10/15 06:16:41 INF Starting PFCP connection: 192.168.14.151:8805 with Node ID: 192.168.14.151 and N3 address: 192.168.13.151
[GIN-debug] [WARNING] Creating an Engine instance with the Logger and Recovery middleware already attached.

[GIN-debug] [WARNING] Running in "debug" mode. Switch to "release" mode in production.
 - using env:   export GIN_MODE=release
 - using code:  gin.SetMode(gin.ReleaseMode)

[GIN-debug] GET    /api/v1/upf_pipeline      --> github.com/edgecomllc/eupf/cmd/core.ListUpfPipeline.func1 (4 handlers)
[GIN-debug] GET    /api/v1/xdp_stats         --> github.com/edgecomllc/eupf/cmd/core.DisplayXdpStatistics.func1 (4 handlers)
[GIN-debug] GET    /api/v1/packet_stats      --> github.com/edgecomllc/eupf/cmd/core.DisplayPacketStats.func1 (4 handlers)
[GIN-debug] GET    /api/v1/config            --> github.com/edgecomllc/eupf/cmd/core.DisplayConfig.func1 (4 handlers)
[GIN-debug] POST   /api/v1/config            --> github.com/edgecomllc/eupf/cmd/core.EditConfig (4 handlers)
[GIN-debug] GET    /api/v1/uplink_pdr_map/:id --> github.com/edgecomllc/eupf/cmd/core.GetUplinkPdrValue.func1 (4 handlers)
[GIN-debug] PUT    /api/v1/uplink_pdr_map/:id --> github.com/edgecomllc/eupf/cmd/core.SetUplinkPdrValue.func1 (4 handlers)
[GIN-debug] GET    /api/v1/qer_map           --> github.com/edgecomllc/eupf/cmd/core.ListQerMapContent.func1 (4 handlers)
[GIN-debug] GET    /api/v1/qer_map/:id       --> github.com/edgecomllc/eupf/cmd/core.GetQerValue.func1 (4 handlers)
[GIN-debug] PUT    /api/v1/qer_map/:id       --> github.com/edgecomllc/eupf/cmd/core.SetQerValue.func1 (4 handlers)
[GIN-debug] GET    /api/v1/far_map/:id       --> github.com/edgecomllc/eupf/cmd/core.GetFarValue.func1 (4 handlers)
[GIN-debug] PUT    /api/v1/far_map/:id       --> github.com/edgecomllc/eupf/cmd/core.SetFarValue.func1 (4 handlers)
[GIN-debug] GET    /api/v1/pfcp_associations --> github.com/edgecomllc/eupf/cmd/core.ListPfcpAssociations.func1 (4 handlers)
[GIN-debug] GET    /api/v1/pfcp_associations/full --> github.com/edgecomllc/eupf/cmd/core.ListPfcpAssociationsFull.func1 (4 handlers)
[GIN-debug] GET    /api/v1/pfcp_sessions     --> github.com/edgecomllc/eupf/cmd/core.ListPfcpSessionsFiltered.func1 (4 handlers)
[GIN-debug] GET    /swagger/*any             --> github.com/swaggo/gin-swagger.CustomWrapHandler.func1 (4 handlers)
[GIN-debug] [WARNING] You trusted all proxies, this is NOT safe. We recommend you to set a value.
Please check https://pkg.go.dev/github.com/gin-gonic/gin#readme-don-t-trust-all-proxies for details.
[GIN-debug] Listening and serving HTTP on :8080

# ss -a -u
State    Recv-Q    Send-Q          Local Address:Port         Peer Address:Port   Process   
UNCONN   0         0              192.168.14.151:8805              0.0.0.0:*                
UNCONN   0         0               127.0.0.53%lo:domain            0.0.0.0:*                
UNCONN   0         0            10.0.2.15%enp0s3:bootpc            0.0.0.0:*

How do eupf bind 2152/udp?
I'm sorry if I misunderstood.

Thank you in advance.

[pirog-spb]

Hi @s5uishida,

No 2152 port binding in linux network stack is occurred, actually.

Data path is implemented in XDP eBPF hook. eBPF program processes data packets directly without any sockets.

[s5uishida]

Hi @pirog-spb

Thank you for your reply.

I don't understand eBPF/XDP properly, so sorry if this is a strange question.

For example, I think that UERANSIM gNB uses 2152/udp when communicating with UPF via N3 interface, but can gNB and UPF communicate without this binding?

I saw the eUPF documentation, but I couldn't figure out how to configure it to work with UERANSIM gNB. I would be very glad if you could let me know some hints on how to start and run the eupf command process directly.

Best regards,

--Shigeru

[pirog-spb]

For example, I think that UERANSIM gNB uses 2152/udp when communicating with UPF via N3 interface, but can gNB and UPF communicate without this binding?
gNB communicates with UPF using 2152/udp. But eUPF don't use socket for processing 2152/udp packets. It processes all incomming packets and gets only 2152/udp as corresponding to N3 interface.

N3 IP address to working on is configured using command args or config (see https://github.com/edgecomllc/eupf/blob/main/docs/Configuration.md)

In order to run eupf directly you can use simple command:

sudo ./bin/eupf
2023/10/17 10:54:07 Unable to read config file, open ./config.yml: no such file or directory
2023/10/17 10:54:07 Get raw config: map[api_address::8080 far_map_size:1024 heartbeat_interval:5 heartbeat_retries:3 heartbeat_timeout:5 interface_name:lo logging_level:info metrics_address::9090 n3_address:127.0.0.1 pdr_map_size:1024 pfcp_address:127.0.0.1:8805 pfcp_node_id:127.0.0.1 qer_map_size:1024 resize_ebpf_maps:false xdp_attach_mode:generic]
2023/10/17 10:54:07 Apply eUPF config: {InterfaceName:[lo] XDPAttachMode:generic ApiAddress::8080 PfcpAddress:127.0.0.1:8805 PfcpNodeId:127.0.0.1 MetricsAddress::9090 N3Address:127.0.0.1 QerMapSize:1024 FarMapSize:1024 PdrMapSize:1024 EbpfMapResize:false HeartbeatRetries:3 HeartbeatInterval:5 HeartbeatTimeout:5 LoggingLevel:info}

To connect eUPF to gNB you have to set at least:

• interface_name proper network interface to run on
• n3_address

To connect eUPF to SMF you have to set:

• pfcp_address
• pfcp_node_id

See config page for exact parameters names (https://github.com/edgecomllc/eupf/blob/main/docs/Configuration.md)

[s5uishida]

Hi @pirog-spb

Thank you for the information.

I have already referred to the your document, created config.yml, and tried eupf.
(I wrote the config.yml at the beginning of this discussion.)

I asked how to communicate with UERANSIM gNB using 2152/udp or other.

[pirog-spb]

Well, eUPF is always ready to communicate with gNB on n3_address and 2152/udp port(but without any sockets). gNB sends packet to UPF after pfcp session crestion

[s5uishida]

Hi @pirog-spb

I'm sorry for replying late.

I was able to confirm the operation.

Thank you very much!