Traffic generator: Config-driven bidirectional external-datapath packet generator

[gab-arrobo]

No description provided.

[Copilot]

🟡 Changes recommended

Same-host setup conflicts with UPF containers, while uplink sizing and PDU Session Container metadata are incorrect.

3 open findings

• Namespace pktgen resources to avoid UPF container and port conflicts · New
• Account for GTP-U encapsulation when sizing uplink frames · New
• Set uplink PDU type and configurable QFI metadata · New

What changed in this PR

Adds a configuration-driven, bidirectional packet generator for testing UPF external datapaths.

Changes:

• Adds configurable uplink/downlink generation and reception.
• Adds automated external-datapath setup.
• Preserves and documents the simulation workflow.

File	Description
scripts/​pktgen_setup.sh	Sets up interfaces, routes, and containers.
docs/​INSTALL.md	Documents external and simulated pktgen workflows.
docs/​images/​ubench-pktgen-sim.svg	Adds the simulation topology diagram.
docs/​images/​ubench-pktgen-sim.svg.license	Adds diagram licensing metadata.
conf/​sim.py	Adds uplink sequence-update helpers.
conf/​pktgen.jsonc	Defines generator interfaces, rates, and traffic parameters.
conf/​pktgen.bess	Implements bidirectional external traffic generation.
conf/​pktgen_sim.bess	Retains the loopback simulation pipeline.
conf/​parser.py	Parses uplink and downlink packet rates.

🧠 Review effort: Balanced

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[Copilot]

🟡 Changes recommended

Driver-mode configuration can diverge and QFI values are not safely validated.

2 open findings

• Unify topology mode between setup script and pktgen configuration · New
• Reject QFI values outside the encodable 6-bit range · New

3 resolved since last review

• Namespace pktgen resources to avoid UPF container and port conflicts
• Set uplink PDU type and configurable QFI metadata
• Account for GTP-U encapsulation when sizing uplink frames

Previously missed (2)

In code that hasn't changed since last review

Do not advertise unsupported sim mode in pktgen configuration

conf/​pktgen.jsonc:8

This mode description contradicts pktgen.bess, which explicitly exits when parser.mode == 'sim'. Point users to the separate simulation pipeline instead of advertising sim as a valid value for this configuration.

Document extra-VF loopback requirement for simulation

docs/​INSTALL.md:446

The simulation pipeline still sends through a PMDPort, and the command below passes a VFIO device; the accompanying diagram also labels this as extra-VF loopback. Calling it “without external interfaces” can lead users to expect a device-free setup that will not run. Describe the extra-VF loopback requirement explicitly.

🧠 Review effort: Balanced

[Copilot]

🟡 Changes recommended

The setup script does not forward CONF_FILE, allowing its namespace topology and BESS pipeline configuration to diverge.

1 open finding

• Forward CONF_FILE to bessctl to prevent config mismatch · New

2 resolved since last review

• Unify topology mode between setup script and pktgen configuration
• Reject QFI values outside the encodable 6-bit range

🧠 Review effort: Balanced

[Copilot]

🔵 Needs a closer look

The hardware-dependent DPDK, AF_XDP, routing, and namespace behavior requires validation on representative networking infrastructure.

0 open findings

1 resolved since last review

• Forward CONF_FILE to bessctl to prevent config mismatch

🧠 Review effort: Balanced

[andybavier]

+1