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

PATCH Superseded Kumar Thangavel 4 participants 6 messages Nov 18, 2021 – Nov 19, 2021

Subsystems (3)

Networking Network drivers Ncsi library

lore

Share & tools

lore

Kumar Thangavel

author

2021-11-18 16:03 UTC #0 lore raw

PATCH v7 1/1 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.

Fixes fb4ee67529ff ("net/ncsi: Add NCSI OEM command support")

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

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

Reviewed-by Paul Menzel <[email protected]>

---
v7:
- Updated padding_bytes as const static int variable

v6:
- Updated type of padding_bytes variable
- Updated type of payload
- Seperated variable declarations and code

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 | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

net/ncsi/ncsi-cmd.c +16 -8

index ba9ae482141b..9a6f10f4833e 100644
@@ -18,6 +18,8 @@
 #include "internal.h"
 #include "ncsi-pkt.h"
 
+const static int padding_bytes = 26;
+
 u32 ncsi_calculate_checksum(unsigned char *data, int len)
 {
 	u32 checksum = 0;

@@ -213,12 +215,17 @@ static int ncsi_cmd_handler_oem(struct sk_buff *skb,
 {
 	struct ncsi_cmd_oem_pkt *cmd;
 	unsigned int len;
+	int payload;
+	/* 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
+	 */
 
+	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 +279,7 @@ 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 +289,14 @@ 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);

Signature · 1 line

2.17.1

Eric Dumazet

2021-11-18 17:14 UTC #1 lore raw

Quoted 8 lines · 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.

Patch title should start with a prefix, identifying which layer/driver is involved.

Probably in this case

net/ncsi: Add payload to be 32-bit aligned to fix dropped packets

Quoted 43 lines

Fixes fb4ee67529ff ("net/ncsi: Add NCSI OEM command support")
Signed-off-by Kumar Thangavel <[email protected]>
Acked-by Samuel Mendoza-Jonas <[email protected]>
Reviewed-by Paul Menzel <[email protected]>
---
v7:
- Updated padding_bytes as const static int variable
v6:
- Updated type of padding_bytes variable
- Updated type of payload
- Seperated variable declarations and code
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 | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)
net/ncsi/ncsi-cmd.c +0 -0
index ba9ae482141b..9a6f10f4833e 100644

net/ncsi/ncsi-cmd.c line 21

Quoted 4 lines

net/ncsi/ncsi-cmd.c +1 -0

@@ -18,6 +18,8 @@
 #include "internal.h"
 #include "ncsi-pkt.h"
 
+const static int padding_bytes = 26;

It would be nice to have some kind of reference, to explain what is this magic value.

Moving the comment [1] here might make sense.

net/ncsi/ncsi-cmd.c static int ncsi_cmd_handler_oem(struct sk_buff *skb, · line 218

Quoted 9 lines

net/ncsi/ncsi-cmd.c +2 -0

+
 u32 ncsi_calculate_checksum(unsigned char *data, int len)
 {
 	u32 checksum = 0;

@@ -213,12 +215,17 @@ static int ncsi_cmd_handler_oem(struct sk_buff *skb,
 {
 	struct ncsi_cmd_oem_pkt *cmd;
 	unsigned int len;
+	int payload;

[1] This comment could be moved before @padding_bytes

Quoted 45 lines

net/ncsi/ncsi-cmd.c +13 -8

+	/* 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
+	 */
 
+	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 +279,7 @@ 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 +289,14 @@ 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);

Kumar Thangavel

author

2021-11-19 08:14 UTC #2 lore raw

PATCH v7 1/1 Add payload to be 32-bit aligned to fix dropped packets

Quoted 12 lines · Eric Dumazet

Quoted 8 lines · 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.

Quoted 7 lines

Patch title should start with a prefix, identifying which layer/driver is involved.
Probably in this case
net/ncsi: Add payload to be 32-bit aligned to fix dropped packets

ACK.

Quoted 121 lines

Quoted 44 lines
Fixes fb4ee67529ff ("net/ncsi: Add NCSI OEM command support")
Signed-off-by Kumar Thangavel <[email protected]>
Acked-by Samuel Mendoza-Jonas <[email protected]>
Reviewed-by Paul Menzel <[email protected]>
---
v7:
- Updated padding_bytes as const static int variable
v6:
- Updated type of padding_bytes variable
- Updated type of payload
- Seperated variable declarations and code
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 | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)
net/ncsi/ncsi-cmd.c +0 -0
index ba9ae482141b..9a6f10f4833e 100644
net/ncsi/ncsi-cmd.c line 21
Quoted 4 lines
net/ncsi/ncsi-cmd.c +1 -0
@@ -18,6 +18,8 @@
 #include "internal.h"
 #include "ncsi-pkt.h"
 
+const static int padding_bytes = 26;
It would be nice to have some kind of reference, to explain what is this magic value.
ACK.
Moving the comment [1] here might make sense.
net/ncsi/ncsi-cmd.c static int ncsi_cmd_handler_oem(struct sk_buff
Quoted 5 lines
net/ncsi/ncsi-cmd.c +1 -0
+
 u32 ncsi_calculate_checksum(unsigned char *data, int len)
 {
      u32 checksum = 0;
@@ -213,12 +215,17 @@ static int ncsi_cmd_handler_oem(struct sk_buff
*skb,
net/ncsi/ncsi-cmd.c static int ncsi_cmd_handler_oem(struct sk_buff *skb, · line 218
Quoted 4 lines
net/ncsi/ncsi-cmd.c +1 -0
 {
      struct ncsi_cmd_oem_pkt *cmd;
      unsigned int len;
+     int payload;
[1] This comment could be moved before @padding_bytes
net/ncsi/ncsi-cmd.c static struct ncsi_request
Quoted 18 lines
net/ncsi/ncsi-cmd.c +8 -4
+     /* 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
+      */
 
+     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 +279,7 @@ static struct ncsi_request
*ncsi_alloc_command(struct ncsi_cmd_arg *nca)
net/ncsi/ncsi-cmd.c static struct ncsi_request
Quoted 8 lines
net/ncsi/ncsi-cmd.c +1 -0
      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 +289,14 @@ static struct ncsi_request
*ncsi_alloc_command(struct ncsi_cmd_arg *nca)
net/ncsi/ncsi-cmd.c static struct ncsi_request *ncsi_alloc_command(struct ncsi_cmd_arg *nca)
Quoted 3 lines
net/ncsi/ncsi-cmd.c +0 -0
              return NULL;
 
      /* NCSI command packet has 16-bytes header, payload, 4 bytes
checksum.
net/ncsi/ncsi-cmd.c static struct ncsi_request · line 292
Quoted 1 line
net/ncsi/ncsi-cmd.c +1 -0
+      * Payload needs padding so that the checksum field following
payload is
Quoted 15 lines
net/ncsi/ncsi-cmd.c +3 -4
+      * 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);

kernel test robot

build bot

2021-11-19 03:15 UTC #3 lore raw

In reply to Kumar Thangavel

Thank you for the patch! Perhaps something to improve:

Hi Kumar,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.16-rc1 next-20211118]
[If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Kumar-Thangavel/Add-payload-to-be-32-bit-aligned-to-fix-dropped-packets/20211119-000541
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 42eb8fdac2fc5d62392dcfcf0253753e821a97b0
config: m68k-randconfig-r005-20211118 (attached as .config)
compiler: m68k-linux-gcc (GCC) 11.2.0

reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/f4e0a51f25ba398ad7f2e3efa5076b2e0ad24e3b
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Kumar-Thangavel/Add-payload-to-be-32-bit-aligned-to-fix-dropped-packets/20211119-000541 git checkout f4e0a51f25ba398ad7f2e3efa5076b2e0ad24e3b
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=m68k

If you fix the issue, kindly add following tag as appropriate

Reported-by kernel test robot <[email protected]>

All warnings (new ones prefixed by >>):

>> net/ncsi/ncsi-cmd.c:21:1: warning: 'static' is not at beginning of declaration [-Wold-style-declaration]
      21 | const static int padding_bytes = 26;
         | ^~~~~

vim +/static +21 net/ncsi/ncsi-cmd.c

    20	
  > 21	const static int padding_bytes = 26;
    22

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all at lists.01.org
-------------- next part --------------
A non-text attachment was scrubbed...
Name: .config.gz
Type: application/gzip
Size: 28516 bytes
Desc: not available
URL: <http://lists.ozlabs.org/pipermail/linux-aspeed/attachments/20211119/1480de93/attachment-0001.gz>

Jakub Kicinski

maintainer

2021-11-19 06:32 UTC #4 lore raw

In reply to Kumar Thangavel

Quoted 1 line · On Thu, 18 Nov 2021 21:33:02 +0530 Kumar Thangavel wrote:

+const static int padding_bytes = 26;

/net/ncsi/ncsi-cmd.c:21:1: warning: ?static? is not at beginning of declaration [-Wold-style-declaration]

   21 | const static int padding_bytes = 26;
      | ^~~~~

Kumar Thangavel

author

2021-11-19 08:13 UTC #5 lore raw

PATCH v7 1/1 Add payload to be 32-bit aligned to fix dropped packets

Quoted 7 lines · Jakub Kicinski

Quoted 1 line · On Thu, 18 Nov 2021 21:33:02 +0530 Kumar Thangavel wrote:
+const static int padding_bytes = 26;
/net/ncsi/ncsi-cmd.c:21:1: warning: ‘static’ is not at beginning of declaration [-Wold-style-declaration]
21 | const static int padding_bytes = 26;

ACK.

Quoted 2 lines

      | ^~~~~