Re: [dpdk-dev] [PATCH v3 2/4] ip_frag: ensure minimum v6 fragmentation length

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

> 
> Similar to v4, we should ensure that at least a minimum fragmentation
> length can be achieved.
> 
> Signed-off-by: Aaron Conole <aconole@redhat.com>
> ---
>  lib/librte_ip_frag/rte_ipv6_fragmentation.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/lib/librte_ip_frag/rte_ipv6_fragmentation.c b/lib/librte_ip_frag/rte_ipv6_fragmentation.c
> index 43449970e5..820a5dc725 100644
> --- a/lib/librte_ip_frag/rte_ipv6_fragmentation.c
> +++ b/lib/librte_ip_frag/rte_ipv6_fragmentation.c
> @@ -79,6 +79,17 @@ rte_ipv6_fragment_packet(struct rte_mbuf *pkt_in,
>  	uint16_t fragment_offset, frag_size;
>  	uint64_t frag_bytes_remaining;
> 
> +	/*
> +	 * The rules on ipv6 fragmentation means we need at least to be
> +	 * greater than the smallest fragment possible - ipv6hdr + frag header
> +	 * + min octets.  We rely on the ipv6_extension_fragment header to
> +	 * include 'data' octets.
> +	 */
> +	if (unlikely(mtu_size <
> +		     (sizeof(struct rte_ipv6_hdr) +
> +		      sizeof(struct ipv6_extension_fragment))))
> +		return -EINVAL;
> +		

Don't know where it comes from.
Reading RFC 8200, it clearly states that min MTU for ipv6 is 1280B.
In fact, I don't see much point in these extra checking.

>  	/*
>  	 * Ensure the IP payload length of all fragments (except the
>  	 * the last fragment) are a multiple of 8 bytes per RFC2460.
> --
> 2.25.1