Messages in this thread | | | Subject | Re: [PATCH] net: ncsi: Adding padding bytes in the payload | From | Paul Menzel <> | Date | Tue, 12 Oct 2021 10:02:03 +0200 |
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Dear Kumar,
Thank you for your patch.
Nit: Could you please use the imperative mood in the commit message summary:
> net: ncsi: Add padding bytes in the payload
Or more descriptive:
> net: ncsi: Padd payload to be 32-bit aligned to fix dropped packets
Am 12.10.21 um 08:22 schrieb Kumar Thangavel: > Update NC-SI command handler (both standard and OEM) to take into > account of payload paddings in allocating skb (in case of payload > size is not 32-bit aligned). > > The checksum field follows payload field, without taking payload > padding into account can cause checksum being truncated, leading to > dropped packets.
How can this be reproduced?
> Signed-off-by: Kumar Thangavel <thangavel.k@hcl.com> > > --- > net/ncsi/ncsi-cmd.c | 21 +++++++++++++++++---- > 1 file changed, 17 insertions(+), 4 deletions(-) > > diff --git a/net/ncsi/ncsi-cmd.c b/net/ncsi/ncsi-cmd.c > index ba9ae482141b..4625fc935603 100644 > --- a/net/ncsi/ncsi-cmd.c > +++ b/net/ncsi/ncsi-cmd.c > @@ -214,11 +214,19 @@ static int ncsi_cmd_handler_oem(struct sk_buff *skb, > struct ncsi_cmd_oem_pkt *cmd; > unsigned int len; > > + /* NC-SI spec requires payload to be padded with 0
It’d be great, if you included the specification version, and section if the requirement.
> + * to 32-bit boundary before the checksum field. > + * Ensure the padding bytes are accounted for in > + * skb allocation > + */ > +
Please remove the blank line.
> + unsigned short payload = ALIGN(nca->payload, 4); > + > len = sizeof(struct ncsi_cmd_pkt_hdr) + 4; > - if (nca->payload < 26) > + if (payload < 26) > len += 26; > else > - len += nca->payload; > + len += payload; > > cmd = skb_put_zero(skb, len); > memcpy(&cmd->mfr_id, nca->data, nca->payload); > @@ -272,6 +280,7 @@ static struct ncsi_request *ncsi_alloc_command(struct ncsi_cmd_arg *nca) > struct net_device *dev = nd->dev; > int hlen = LL_RESERVED_SPACE(dev); > int tlen = dev->needed_tailroom; > + int payload; > int len = hlen + tlen; > struct sk_buff *skb; > struct ncsi_request *nr; > @@ -281,14 +290,18 @@ static struct ncsi_request *ncsi_alloc_command(struct ncsi_cmd_arg *nca) > return NULL; > > /* NCSI command packet has 16-bytes header, payload, 4 bytes checksum. > + * Payload needs padding so that the checksum field follwoing payload is
following
> + * aligned to 32bit boundary.
32-bit
> * The packet needs padding if its payload is less than 26 bytes to > * meet 64 bytes minimal ethernet frame length. > */ > len += sizeof(struct ncsi_cmd_pkt_hdr) + 4; > - if (nca->payload < 26) > + > + payload = ALIGN(nca->payload, 4); > + if (payload < 26) > len += 26; > else > - len += nca->payload; > + len += payload; > > /* Allocate skb */ > skb = alloc_skb(len, GFP_ATOMIC); >
Besides the nits, this looks fine to me.
Kind regards,
Paul
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