On Wed, May 08, 2024 at 11:10:41AM +0200, jan@openbsd.org wrote:
> When we forward LRO packets from ix(4) via ixl(4) with an MSS that is
> out of range (64 - 9668) the ixl(4) inteface get stucked. This could
> happen when two packet with 30 bytes payload each will coalesced by the
> ix(4) interface.
> 
> The x710 specification said:
> 
> 	The MSS should not be set to a lower value than 64 or larger
> 	than 9668 bytes.
> 
> Thus, we have to round up/off the MSS to keep it in the specified range.
> 
> ok?

OK bluhm@

> Index: dev/pci/if_ixl.c
> ===================================================================
> RCS file: /cvs/src/sys/dev/pci/if_ixl.c,v
> diff -u -p -r1.99 if_ixl.c
> --- dev/pci/if_ixl.c	7 May 2024 18:35:23 -0000	1.99
> +++ dev/pci/if_ixl.c	8 May 2024 08:53:31 -0000
> @@ -2854,7 +2854,11 @@ ixl_tx_setup_offload(struct mbuf *m0, st
>  
>  			hlen += ext.tcphlen;
>  
> -			outlen = m0->m_pkthdr.ph_mss;
> +			/*
> +			 * The MSS should not be set to a lower value than 64
> +			 * or larger than 9668 bytes.
> +			 */
> +			outlen = MIN(9668, MAX(64, m0->m_pkthdr.ph_mss));
>  			paylen = m0->m_pkthdr.len - ETHER_HDR_LEN - hlen;
>  
>  			ring = IXL_DMA_KVA(&txr->txr_mem);