[BUG] icmpv6 responses generated by udp_input are not handled properly in sixlowpan

[Laczen]

Description / Steps to reproduce the issue

When using udp over sixlowpan the processing of udp packets can generate a icmpv6 response when icmpv6 is enabled. These responses are not handled properly.

To reproduce: setup 2 nodes for sixlowpan communication (e.g. using espnow).

Use udpclient to send packets from one node to a "server" node (without enabling udpserver).
The server node will block.

(see #15962 (comment))

On which OS does this issue occur?

[OS: Linux]

What is the version of your OS?

Ubuntu 24.04

NuttX Version

master

Issue Architecture

[Arch: xtensa]

Issue Area

[Area: Networking]

Host information

No response

Verification

• I have verified before submitting the report.

[Laczen]

Solved by #15980.