Question regarding duplicate fragment handling in DPDK IP reassembly library

[Stephen Hemminger]

On Mon, 15 Jun 2026 12:39:48 +0000
Samyak Jain <samyak.jain at amantyatech.com> wrote:

> Hi DPDK Community,
> 
> I am using DPDK 25.11 and evaluating the IP reassembly library
> (librte_ip_frag).
> 
> During testing, I observed that duplicate fragments appear to cause reassembly failure and the fragment context gets invalidated.
> 
> I would like to know:
> 
> 1. Is duplicate fragment handling intentionally unsupported in
>    rte_ipv4_frag_reassemble_packet() / rte_ipv6_frag_reassemble_packet()?
> 
> 2. Has there been any upstream discussion or patch to support
>    duplicate fragments while still rejecting conflicting
>    fragments?
> 
> 3. Are there any recommended approaches for applications that need
>    Linux-like duplicate fragment tolerance?
> 
> Any guidance would be appreciated.
> 
> Thanks & Regards,
> Samyak Jain
> 

Short answer: yes it is buggy, no it shouldn't be.
Looking into it but not a simple answer