[PATCH v5] Add payload to be 32-bit aligned to fix dropped packets
Kumar Thangavel
kumarthangavel.hcl at gmail.com
Tue Nov 16 01:48:46 AEDT 2021
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.
Fixes: fb4ee67529ff ("net/ncsi: Add NCSI OEM command support")
Signed-off-by: Kumar Thangavel <thangavel.k at hcl.com>
Acked-by: Samuel Mendoza-Jonas <sam at mendozajonas.com>
Reviewed-by: Paul Menzel <pmenzel at molgen.mpg.de>
---
v5:
- Added Fixes tag
- Added const variable for padding_bytes
v4:
- Used 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 | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)
diff --git a/net/ncsi/ncsi-cmd.c b/net/ncsi/ncsi-cmd.c
index ba9ae482141b..9571bb4dd991 100644
--- a/net/ncsi/ncsi-cmd.c
+++ b/net/ncsi/ncsi-cmd.c
@@ -18,6 +18,8 @@
#include "internal.h"
#include "ncsi-pkt.h"
+const unsigned short padding_bytes = 26;
+
u32 ncsi_calculate_checksum(unsigned char *data, int len)
{
u32 checksum = 0;
@@ -213,12 +215,16 @@ 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, padding_bytes);
cmd = skb_put_zero(skb, len);
memcpy(&cmd->mfr_id, nca->data, nca->payload);
@@ -272,6 +278,7 @@ 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 +288,14 @@ 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
+ * 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, padding_bytes);
/* Allocate skb */
skb = alloc_skb(len, GFP_ATOMIC);
--
2.17.1
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