[dpdk-dev] [PATCH 1/1] ip_frag: fix creating ipv6 fragment extension header
Dumitrescu, Cristian
cristian.dumitrescu at intel.com
Mon Sep 7 13:21:31 CEST 2015
> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Ananyev,
> Konstantin
> Sent: Friday, September 4, 2015 6:51 PM
> To: Azarewicz, PiotrX T; dev at dpdk.org
> Subject: Re: [dpdk-dev] [PATCH 1/1] ip_frag: fix creating ipv6 fragment
> extension header
>
> Hi Piotr,
>
> > -----Original Message-----
> > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Piotr
> > Sent: Wednesday, September 02, 2015 3:13 PM
> > To: dev at dpdk.org
> > Subject: [dpdk-dev] [PATCH 1/1] ip_frag: fix creating ipv6 fragment
> extension header
> >
> > From: Piotr Azarewicz <piotrx.t.azarewicz at intel.com>
> >
> > Previous implementation won't work on every environment. The order of
> > allocation of bit-fields within a unit (high-order to low-order or
> > low-order to high-order) is implementation-defined.
> > Solution: used bytes instead of bit fields.
>
> Seems like right thing to do to me.
> Though I think we also should replace:
> union {
> struct {
> uint16_t frag_offset:13; /**< Offset from the start of the packet
> */
> uint16_t reserved2:2; /**< Reserved */
> uint16_t more_frags:1;
> /**< 1 if more fragments left, 0 if last fragment */
> };
> uint16_t frag_data;
> /**< union of all fragmentation data */
> };
>
> With just:
> uint16_t frag_data;
> and probably provide macros to read/set fragment_offset and more_flags
> values.
> Otherwise people might keep using the wrong layout.
> Konstantin
>
I agree with your proposal, but wouldn't this be an ABI change? To avoid an ABI change, we should probably leave the union?
> >
> > Signed-off-by: Piotr Azarewicz <piotrx.t.azarewicz at intel.com>
> > ---
> > lib/librte_ip_frag/rte_ipv6_fragmentation.c | 6 ++----
> > 1 file changed, 2 insertions(+), 4 deletions(-)
> >
> > diff --git a/lib/librte_ip_frag/rte_ipv6_fragmentation.c
> b/lib/librte_ip_frag/rte_ipv6_fragmentation.c
> > index 0e32aa8..7342421 100644
> > --- a/lib/librte_ip_frag/rte_ipv6_fragmentation.c
> > +++ b/lib/librte_ip_frag/rte_ipv6_fragmentation.c
> > @@ -65,10 +65,8 @@ __fill_ipv6hdr_frag(struct ipv6_hdr *dst,
> >
> > fh = (struct ipv6_extension_fragment *) ++dst;
> > fh->next_header = src->proto;
> > - fh->reserved1 = 0;
> > - fh->frag_offset = rte_cpu_to_be_16(fofs);
> > - fh->reserved2 = 0;
> > - fh->more_frags = rte_cpu_to_be_16(mf);
> > + fh->reserved1 = 0;
> > + fh->frag_data = rte_cpu_to_be_16((fofs & ~IPV6_HDR_FO_MASK) |
> mf);
> > fh->id = 0;
> > }
> >
> > --
> > 1.7.9.5
More information about the dev
mailing list