Add payload to be 32-bit aligned to fix dropped packets

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.

Signed-off-by Kumar Thangavel <[email protected]>

Acked-by Samuel Mendoza-Jonas <[email protected]>

Reviewed-by Paul Menzel <[email protected]>

---
v4:
- Updated existing macro for max function

v3:
- Added Macro for MAX
- Fixed the missed semicolon

v2:
- Added NC-SI spec version and section
- Removed blank line
- corrected spellings

v1:
- Initial draft

---
 net/ncsi/ncsi-cmd.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

net/ncsi/ncsi-cmd.c +9 -4

index ba9ae482141b..e44fe138c20f 100644
@@ -213,12 +213,16 @@ static int ncsi_cmd_handler_oem(struct sk_buff *skb,
 {
        struct ncsi_cmd_oem_pkt *cmd;
        unsigned int len;
+       /* NC-SI spec DSP_0222_1.2.0, section 8.2.2.2
+        * requires payload to be padded with 0 to
+        * 32-bit boundary before the checksum field.
+        * Ensure the padding bytes are accounted for in
+        * skb allocation
+        */
 
+       unsigned short payload = ALIGN(nca->payload, 4);
        len = sizeof(struct ncsi_cmd_pkt_hdr) + 4;
-       if (nca->payload < 26)
-               len += 26;
-       else
-               len += nca->payload;
+       len += max(payload, 26);
 
        cmd = skb_put_zero(skb, len);
        memcpy(&cmd->mfr_id, nca->data, nca->payload);

@@ -272,6 +276,7 @@ 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;

net/ncsi/ncsi-cmd.c +0 -0

@@ -281,14 +286,14 @@ 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 following
payload is

net/ncsi/ncsi-cmd.c +3 -5

+        * aligned to 32-bit boundary.
         * 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)
-               len += 26;
-       else
-               len += nca->payload;
+       payload = ALIGN(nca->payload, 4);
+       len += max(payload, 26);
 
        /* Allocate skb */
        skb = alloc_skb(len, GFP_ATOMIC);
--

2.17.1

Could you please review the patch and provide your feedback?

Quoted 1 line · On Wed, 3 Nov 2021 20:41:56 +0530 Kumar Thangavel wrote:

Could you please review the patch and provide your feedback?

You missed CCing netdev@ again. You need to CC the mailing list to get the patch considered for merging.

Hi Jakub,

Thanks for your response.

Somehow, My mails are not delivered to netdev at vger.kernel.org.

So, I removed it in my last 2 patchsets.

I will try again to CCing netdev at vger.kernel.org.

Quoted 9 lines · On Wed, 3 Nov 2021 21:43:03 +0530 Kumar Thangavel wrote:

Hi Jakub,

Thanks for your response.

Somehow, My mails are not delivered to [email protected].

So, I removed it in my last 2 patchsets.

I will try again to CCing [email protected].

For normal replies you need to use plain text, not HTML. The mailing list rejects HTML emails. But the patch should go thru, we'll see.