During an if-condition evaluation, a 2-bit flag evaluates to 'true' for '0x1', '0x2' and '0x3'. Thus, from this perspective these flags are indistinguishable. To make them distinct, respective bits must be extracted with a mask and then checked for strict equality. Specifically here, even if `PKT_TX_UDP_CKSUM` (value '0x3') was set, the expression `mbuf->ol_flags & PKT_TX_TCP` (the second flag of value '0x1') is evaluated first and the result is 'true'. In consequence, for UDP packets the execution flow enters an incorrect branch. Fixes: 56b8b9b7e5d2 (net/ena: convert to new Tx offloads API) Cc: stable@dpdk.org Signed-off-by: Maciej Bielski <mba@semihalf.com> Reported-by: Eduard Serra <eduser25@gmail.com> --- drivers/net/ena/ena_ethdev.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/net/ena/ena_ethdev.c b/drivers/net/ena/ena_ethdev.c index f58334080..eb9d643f0 100644 --- a/drivers/net/ena/ena_ethdev.c +++ b/drivers/net/ena/ena_ethdev.c @@ -330,12 +330,13 @@ static inline void ena_tx_mbuf_prepare(struct rte_mbuf *mbuf, } /* check if L4 checksum is needed */ - if ((mbuf->ol_flags & PKT_TX_TCP_CKSUM) && + if (((mbuf->ol_flags & PKT_TX_L4_MASK) == PKT_TX_TCP_CKSUM) && (queue_offloads & DEV_TX_OFFLOAD_TCP_CKSUM)) { ena_tx_ctx->l4_proto = ENA_ETH_IO_L4_PROTO_TCP; ena_tx_ctx->l4_csum_enable = true; - } else if ((mbuf->ol_flags & PKT_TX_UDP_CKSUM) && - (queue_offloads & DEV_TX_OFFLOAD_UDP_CKSUM)) { + } else if (((mbuf->ol_flags & PKT_TX_L4_MASK) == + PKT_TX_UDP_CKSUM) && + (queue_offloads & DEV_TX_OFFLOAD_UDP_CKSUM)) { ena_tx_ctx->l4_proto = ENA_ETH_IO_L4_PROTO_UDP; ena_tx_ctx->l4_csum_enable = true; } else { -- 2.20.1
czw., 1 sie 2019 o 13:45 Maciej Bielski <mba@semihalf.com> napisał(a): > > During an if-condition evaluation, a 2-bit flag evaluates to 'true' for > '0x1', '0x2' and '0x3'. Thus, from this perspective these flags are > indistinguishable. To make them distinct, respective bits must be > extracted with a mask and then checked for strict equality. > > Specifically here, even if `PKT_TX_UDP_CKSUM` (value '0x3') was set, the > expression `mbuf->ol_flags & PKT_TX_TCP` (the second flag of value > '0x1') is evaluated first and the result is 'true'. In consequence, for > UDP packets the execution flow enters an incorrect branch. > > Fixes: 56b8b9b7e5d2 (net/ena: convert to new Tx offloads API) > Cc: stable@dpdk.org > > Signed-off-by: Maciej Bielski <mba@semihalf.com> > Reported-by: Eduard Serra <eduser25@gmail.com> Acked-by: Michal Krawczyk <mk@semihalf.com> > --- > drivers/net/ena/ena_ethdev.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/net/ena/ena_ethdev.c b/drivers/net/ena/ena_ethdev.c > index f58334080..eb9d643f0 100644 > --- a/drivers/net/ena/ena_ethdev.c > +++ b/drivers/net/ena/ena_ethdev.c > @@ -330,12 +330,13 @@ static inline void ena_tx_mbuf_prepare(struct rte_mbuf *mbuf, > } > > /* check if L4 checksum is needed */ > - if ((mbuf->ol_flags & PKT_TX_TCP_CKSUM) && > + if (((mbuf->ol_flags & PKT_TX_L4_MASK) == PKT_TX_TCP_CKSUM) && > (queue_offloads & DEV_TX_OFFLOAD_TCP_CKSUM)) { > ena_tx_ctx->l4_proto = ENA_ETH_IO_L4_PROTO_TCP; > ena_tx_ctx->l4_csum_enable = true; > - } else if ((mbuf->ol_flags & PKT_TX_UDP_CKSUM) && > - (queue_offloads & DEV_TX_OFFLOAD_UDP_CKSUM)) { > + } else if (((mbuf->ol_flags & PKT_TX_L4_MASK) == > + PKT_TX_UDP_CKSUM) && > + (queue_offloads & DEV_TX_OFFLOAD_UDP_CKSUM)) { > ena_tx_ctx->l4_proto = ENA_ETH_IO_L4_PROTO_UDP; > ena_tx_ctx->l4_csum_enable = true; > } else { > -- > 2.20.1 >
01/08/2019 14:08, Michał Krawczyk:
> czw., 1 sie 2019 o 13:45 Maciej Bielski <mba@semihalf.com> napisał(a):
> >
> > During an if-condition evaluation, a 2-bit flag evaluates to 'true' for
> > '0x1', '0x2' and '0x3'. Thus, from this perspective these flags are
> > indistinguishable. To make them distinct, respective bits must be
> > extracted with a mask and then checked for strict equality.
> >
> > Specifically here, even if `PKT_TX_UDP_CKSUM` (value '0x3') was set, the
> > expression `mbuf->ol_flags & PKT_TX_TCP` (the second flag of value
> > '0x1') is evaluated first and the result is 'true'. In consequence, for
> > UDP packets the execution flow enters an incorrect branch.
> >
> > Fixes: 56b8b9b7e5d2 (net/ena: convert to new Tx offloads API)
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Maciej Bielski <mba@semihalf.com>
> > Reported-by: Eduard Serra <eduser25@gmail.com>
> Acked-by: Michal Krawczyk <mk@semihalf.com>
Applied, thanks