ER: Implement support for Jumbo Frames

[anzimber]

Is your feature request related to a problem? Please describe.

Currently, bngblaster enforces a maximum stream length of 3936 bytes when using packet_mmap, resulting in the following error:

Set max allowed stream length to 3936 because of packet_mmap limitations
JSON config error: Invalid value for stream->length (must be between 76 and 3936)

This limitation prevents testing of jumbo frames (e.g. ~9000 bytes MTU), which are commonly used in modern networks (e.g. data center fabrics, transport networks, and certain broadband access scenarios).

As a result, it is not possible to validate realistic end-to-end behavior for:

• Jumbo Ethernet frames (e.g. MTU 9000+)
• QinQ encapsulations with larger payloads
• High-throughput scenarios where jumbo frames are required to reduce CPU overhead

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Describe the solution you'd like

Add support for jumbo frames in bngblaster, allowing stream lengths beyond the current ~4k limitation.

The goal is to enable realistic testing with MTUs up to ~9000 bytes and beyond.

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Describe alternatives you've considered

• io-mode raw cant be used in our case, traffic receiving didnt work due to loosing vlans

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Additional context

• Tested on Linux with interfaces configured for MTU 9216

• Limitation appears tied to packet_mmap configuration and/or internal buffer sizing

• Jumbo frame support is increasingly important for:

  • Broadband access testing
  • Data center interconnect validation
  • High-performance benchmarking scenarios

If helpful, I’m happy to assist with testing potential implementations or validating different backend approaches.

[GIC-de]

Please verify with latest dev branch.

COPNFIG:

{
    "interfaces": {
        "jumbo-frames": true
    }
}