Re: [PATCH v4 01/12] net: eth: Add a helper to pad a short Ethernet frame

[Bin Meng]

On Tue, Mar 16, 2021 at 11:09 PM Philippe Mathieu-Daudé
<philmd@redhat.com> wrote:
>
> On 3/16/21 1:04 PM, Bin Meng wrote:
> > Add a helper to pad a short Ethernet frame to the minimum required
> > length, which can be used by backend codes.
>
> "backend codes" sounds odd but I'm not native English speaker.
> I'd have used "backends' code" instead...
>

Will update in v5.

> > Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
> >
> > ---
> >
> > Changes in v4:
> > - change 'ethernet' to 'Ethernet'
> > - do not inline the helper
> > - check the padded buffer size to avoid buffer overflow
> >
> > Changes in v3:
> > - use 'without' instead of 'sans'
> > - add a helper to pad short frames
> >
> >  include/net/eth.h | 17 +++++++++++++++++
> >  net/eth.c         | 17 +++++++++++++++++
> >  2 files changed, 34 insertions(+)
> >
> > diff --git a/include/net/eth.h b/include/net/eth.h
> > index 0671be6916..6aabbdd0d3 100644
> > --- a/include/net/eth.h
> > +++ b/include/net/eth.h
> > @@ -31,6 +31,7 @@
> >
> >  #define ETH_ALEN 6
> >  #define ETH_HLEN 14
> > +#define ETH_ZLEN 60     /* Min. octets in frame without FCS */
> >
> >  struct eth_header {
> >      uint8_t  h_dest[ETH_ALEN];   /* destination eth addr */
> > @@ -422,4 +423,20 @@ bool
> >  eth_parse_ipv6_hdr(const struct iovec *pkt, int pkt_frags,
> >                     size_t ip6hdr_off, eth_ip6_hdr_info *info);
> >
> > +/**
> > + * eth_pad_short_frame - pad a short frame to the minimum Ethernet frame 
> > length
> > + *
> > + * If the Ethernet frame size is shorter than 60 bytes, it will be padded 
> > to
> > + * 60 bytes at the address @padded_pkt.
> > + *
> > + * @padded_pkt: buffer address to hold the padded frame
> > + * @padded_buflen: buffer length of @padded_pkt. If the frame is padded, 
> > it is
> > + *                 written to ETH_ZLEN, otherwise it remains unchanged.
>
>  @padded_buflen: pointer holding length of @padded_pkt. If the frame is
>                  padded, the length will be updated to the padded one.

Will update in v5.

>
> Otherwise:
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>
> (since you describe frames, maybe s/pkt/frame/?)
>

By looking at the existing codes, 'pkt' seems to be a common variable
name representing ethernet frames, hence I will keep this as it is.

Regards,
Bin