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

PATCH Superseded Kumar Thangavel 3 participants 4 messages Nov 10, 2021 – Nov 15, 2021

Subsystems (3)
Networking Network drivers Ncsi library

v4 of 8 Superseded Latest is v8 →

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Kumar Thangavel

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#0 lore raw

PATCH v4 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.

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 +13 -8
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;

@@ -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
+	 * 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);
Signature · 1 line
2.17.1
#1 lore raw

11/10/21 12:54 PM, Kumar Thangavel ?????:

Quoted 7 lines

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.

Please add Fixes tag

Quoted 35 lines
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 +1 -0
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

net/ncsi/ncsi-cmd.c static int ncsi_cmd_handler_oem(struct sk_buff *skb, · line 219

Quoted 10 lines
net/ncsi/ncsi-cmd.c +6 -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;

Would be nice to have a constant

Quoted 34 lines
net/ncsi/ncsi-cmd.c +6 -6
-	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;

@@ -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
+	 * 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);
build bot
#2 lore raw
In reply to Kumar Thangavel
Thank you for the patch! Yet something to improve:

Hi Kumar,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v5.15 next-20211111]
[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/20211110-175537
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git cb690f5238d71f543f4ce874aa59237cf53a877c
config: hexagon-buildonly-randconfig-r006-20211112 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 63ef0e17e28827eae53133b3467bdac7d9729318)

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/263eaf647698f405f4f9905c947bf73b87c55b79
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/20211110-175537 git checkout 263eaf647698f405f4f9905c947bf73b87c55b79
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=hexagon

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

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

All errors (new ones prefixed by >>):

>> net/ncsi/ncsi-cmd.c:225:9: error: comparison of distinct pointer types ('typeof (payload) *' (aka 'unsigned short *') and 'typeof (26) *' (aka 'int *')) [-Werror,-Wcompare-distinct-pointer-types]
           len += max(payload, 26);
                  ^~~~~~~~~~~~~~~~
   include/linux/minmax.h:52:19: note: expanded from macro 'max'
   #define max(x, y)       __careful_cmp(x, y, >)
                           ^~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:36:24: note: expanded from macro '__careful_cmp'
           __builtin_choose_expr(__safe_cmp(x, y), \
                                 ^~~~~~~~~~~~~~~~
   include/linux/minmax.h:26:4: note: expanded from macro '__safe_cmp'
                   (__typecheck(x, y) && __no_side_effects(x, y))
                    ^~~~~~~~~~~~~~~~~
   include/linux/minmax.h:20:28: note: expanded from macro '__typecheck'
           (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
                      ~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~

1 error generated.

vim +225 net/ncsi/ncsi-cmd.c

210
211 static int ncsi_cmd_handler_oem(struct sk_buff *skb,
212 struct ncsi_cmd_arg *nca)
213 {
214 struct ncsi_cmd_oem_pkt *cmd;
215 unsigned int len;
216 /* NC-SI spec DSP_0222_1.2.0, section 8.2.2.2
217 * requires payload to be padded with 0 to
218 * 32-bit boundary before the checksum field.
219 * Ensure the padding bytes are accounted for in
220 * skb allocation
221 */
222
223 unsigned short payload = ALIGN(nca->payload, 4);
224 len = sizeof(struct ncsi_cmd_pkt_hdr) + 4;

 > 225		len += max(payload, 26);

226
227 cmd = skb_put_zero(skb, len);
228 memcpy(&cmd->mfr_id, nca->data, nca->payload);
229 ncsi_cmd_build_header(&cmd->cmd.common, nca);
230
231 return 0;
232 }
233

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all at lists.01.org
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build bot
#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-20211115]
[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/20211110-175537
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git cb690f5238d71f543f4ce874aa59237cf53a877c
config: riscv-buildonly-randconfig-r006-20211115 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project fbe72e41b99dc7994daac300d208a955be3e4a0a)

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
# install riscv cross compiling tool for clang build
# apt-get install binutils-riscv64-linux-gnu
# https://github.com/0day-ci/linux/commit/263eaf647698f405f4f9905c947bf73b87c55b79
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/20211110-175537 git checkout 263eaf647698f405f4f9905c947bf73b87c55b79
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=riscv

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:225:9: warning: comparison of distinct pointer types ('typeof (payload) *' (aka 'unsigned short *') and 'typeof (26) *' (aka 'int *')) [-Wcompare-distinct-pointer-types]
           len += max(payload, 26);
                  ^~~~~~~~~~~~~~~~
   include/linux/minmax.h:52:19: note: expanded from macro 'max'
   #define max(x, y)       __careful_cmp(x, y, >)
                           ^~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:36:24: note: expanded from macro '__careful_cmp'
           __builtin_choose_expr(__safe_cmp(x, y), \
                                 ^~~~~~~~~~~~~~~~
   include/linux/minmax.h:26:4: note: expanded from macro '__safe_cmp'
                   (__typecheck(x, y) && __no_side_effects(x, y))
                    ^~~~~~~~~~~~~~~~~
   include/linux/minmax.h:20:28: note: expanded from macro '__typecheck'
           (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
                      ~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~

1 warning generated.

vim +225 net/ncsi/ncsi-cmd.c

210
211 static int ncsi_cmd_handler_oem(struct sk_buff *skb,
212 struct ncsi_cmd_arg *nca)
213 {
214 struct ncsi_cmd_oem_pkt *cmd;
215 unsigned int len;
216 /* NC-SI spec DSP_0222_1.2.0, section 8.2.2.2
217 * requires payload to be padded with 0 to
218 * 32-bit boundary before the checksum field.
219 * Ensure the padding bytes are accounted for in
220 * skb allocation
221 */
222
223 unsigned short payload = ALIGN(nca->payload, 4);
224 len = sizeof(struct ncsi_cmd_pkt_hdr) + 4;

 > 225		len += max(payload, 26);

226
227 cmd = skb_put_zero(skb, len);
228 memcpy(&cmd->mfr_id, nca->data, nca->payload);
229 ncsi_cmd_build_header(&cmd->cmd.common, nca);
230
231 return 0;
232 }
233

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all at lists.01.org
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