Hi Andrew,
On Wed, May 27, 2020 at 03:32:56PM +0100, Andrew Rybchenko wrote:
> Pseudo-header checksum calculation requires contiguous headers.
> There is no any formal requirements on data location and mbuf
> structure which could be used by the application.
>
> Make corresponding check to be done in non-debug build as well
> to avoid bad accesses, incorrect checksum caclculation and to
typo: caclculation -> calculation
> return appropriate error from Tx prepare.
>
> Make no-offloads check more precise and do it in non-debug build
> as well to avoid contiguous headers check and Tx prepare failure
> if it is not actually required.
>
> Signed-off-by: Andrew Rybchenko <arybche...@solarflare.com>
> ---
> lib/librte_net/rte_net.h | 6 +-----
> 1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/lib/librte_net/rte_net.h b/lib/librte_net/rte_net.h
> index 1560ecfa46..1edc283a47 100644
> --- a/lib/librte_net/rte_net.h
> +++ b/lib/librte_net/rte_net.h
> @@ -120,20 +120,17 @@ rte_net_intel_cksum_flags_prepare(struct rte_mbuf *m,
> uint64_t ol_flags)
> struct rte_udp_hdr *udp_hdr;
> uint64_t inner_l3_offset = m->l2_len;
>
> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
> /*
> * Does packet set any of available offloads?
> * Mainly it is required to avoid fragmented headers check if
> * no offloads are requested.
> */
> - if (!(ol_flags & PKT_TX_OFFLOAD_MASK))
> + if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK)))
> return 0;
Agree, the packet is modified only if one of these flag is set.
> -#endif
>
> if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6))
> inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
>
> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
> /*
> * Check if headers are fragmented.
> * The check could be less strict depending on which offloads are
> @@ -142,7 +139,6 @@ rte_net_intel_cksum_flags_prepare(struct rte_mbuf *m,
> uint64_t ol_flags)
> if (unlikely(rte_pktmbuf_data_len(m) <
> inner_l3_offset + m->l3_len + m->l4_len))
> return -ENOTSUP;
> -#endif
Yes, despite the documentation of thus function says that used headers
should be in the first data segment of the mbuf, when it is used through
the ethdev tx_prepare() API there is no such requirement.
So yes, it looks safer to do these checks even if debug is off. They
will only be done when doing tx offload, so I guess it is ok in terms of
performance.
Maybe it is worth mentioning commit dfc6b2fd8da3 ("mbuf: remove Intel
offload checks from generic API") in the commit log?
>
> if (ol_flags & PKT_TX_IPV4) {
> ipv4_hdr = rte_pktmbuf_mtod_offset(m, struct rte_ipv4_hdr *,
> --
> 2.17.1
>
Acked-by: Olivier Matz <olivier.m...@6wind.com>
