Add payload to be 32-bit aligned to fix dropped packets
Subsystems (3)
PATCH v2 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.
---
v2:
- Added NC-SI spec version and section
- Removed blank line
- corrected spellings
v1:
- Initial draft.
--- net/ncsi/ncsi-cmd.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-)
net/ncsi/ncsi-cmd.c +15 -4
@@ -213,12 +213,19 @@ 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 ) +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 +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 +289,17 @@ 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 ) + payload = ALIGN(nca->payload, 4) +if (payload <26 ) len +=26 ;else - len += nca->payload; + len += payload;/* Allocate skb */ skb =alloc_skb (len,GFP_ATOMIC );
Signature · 1 line
2.17.1
Jakub Kicinski
maintainernet/ncsi/ncsi-cmd.c static struct ncsi_request *ncsi_alloc_command(struct ncsi_cmd_arg *nca) · line 302
Quoted 8 lines · On Tue, 19 Oct 2021 20:11:27 +0530 Kumar Thangavel wrote:
net/ncsi/ncsi-cmd.c +3
-2len +=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;
You round up to 4 and then add 26 if the result is smaller. 26 is not a multiple of 4. Is this intentional?
Also you can write this on one line:
len += max(payload, 26);
PATCH v2 1/1 Add payload to be 32-bit aligned to fix dropped packets
Thanks Jakub for your comments.
Please find my response inline below.
Quoted 10 lines · Jakub Kicinski
net/ncsi/ncsi-cmd.c static struct ncsi_request *ncsi_alloc_command(struct ncsi_cmd_arg *nca) · line 302
Quoted 8 lines · On Tue, 19 Oct 2021 20:11:27 +0530 Kumar Thangavel wrote:
len += sizeof(struct ncsi_cmd_pkt_hdr) + 4;net/ncsi/ncsi-cmd.c +3
-2-if (nca->payload <26 ) + payload = ALIGN(nca->payload, 4) +if (payload <26 ) len +=26 ;else - len += nca->payload; + len += payload;
Quoted 4 lines
You round up to 4 and then add 26 if the result is smaller. 26 is not a multiple of 4. Is this intentional?
Kumar : This is intentional. The total number of bytes should be 64.
This 64 bytes includes Ethernet header, NC-SI header and payload, pldm header and payload.
Some pldm commands payload is less than 26. So we added
remaining bytes to match with 64 and which is 4 bytes aligned.
Also you can write this on one line:
Quoted 3 lines
len += max(payload, 26);Kumar : Ack. Will update in the next patch set.
Jakub Kicinski
maintainernet/ncsi/ncsi-cmd.c static struct ncsi_request *ncsi_alloc_command(struct ncsi_cmd_arg *nca) · line 298
Quoted 1 line · On Tue, 19 Oct 2021 20:11:27 +0530 Kumar Thangavel wrote:
net/ncsi/ncsi-cmd.c +1
-0+ payload =ALIGN (nca->payload,4 )
This is missing a semicolon.
PATCH v2 1/1 Add payload to be 32-bit aligned to fix dropped packets
Quoted 5 lines · Jakub Kicinski
Quoted 1 line · On Tue, 19 Oct 2021 20:11:27 +0530 Kumar Thangavel wrote:
+ payload =
ALIGN(nca->payload, 4)This is missing a semicolon.
Kumar : Ack. Will fix this in next PS.
kernel test robot
build botThank 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-rc6 next-20211019]
[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/20211019-225018 base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 519d81956ee277b4419c723adfb154603c2565ba config: i386-randconfig-a005-20211019 (attached as .config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project b37efed957ed0a0193d80020aefd55cb587dfc1f)
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/177d89a1966a0830ac30b8962ac9af76c1d675ae
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/20211019-225018 git checkout 177d89a1966a0830ac30b8962ac9af76c1d675ae
# save the attached .config to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash net/
If you fix the issue, kindly add following tag as appropriate
All errors (new ones prefixed by >>):
>> net/ncsi/ncsi-cmd.c:298:34: error: expected ';' after expression
payload = ALIGN(nca->payload, 4)
^
;1 error generated.
vim +298 net/ncsi/ncsi-cmd.c
274
275 static struct ncsi_request *ncsi_alloc_command(struct ncsi_cmd_arg *nca)
276 {
277 struct ncsi_dev_priv *ndp = nca->ndp;
278 struct ncsi_dev *nd = &ndp->ndev;
279 struct net_device *dev = nd->dev;
280 int hlen = LL_RESERVED_SPACE(dev);
281 int tlen = dev->needed_tailroom;
282 int payload;
283 int len = hlen + tlen;
284 struct sk_buff *skb;
285 struct ncsi_request *nr;
286
287 nr = ncsi_alloc_request(ndp, nca->req_flags);
288 if (!nr)
289 return NULL;
290
291 /* NCSI command packet has 16-bytes header, payload, 4 bytes checksum.
292 * Payload needs padding so that the checksum field following payload is
293 * aligned to 32-bit boundary.
294 * The packet needs padding if its payload is less than 26 bytes to
295 * meet 64 bytes minimal ethernet frame length.
296 */
297 len += sizeof(struct ncsi_cmd_pkt_hdr) + 4;
> 298 payload = ALIGN(nca->payload, 4)
299 if (payload < 26)
300 len += 26;
301 else
302 len += payload;
303
304 /* Allocate skb */
305 skb = alloc_skb(len, GFP_ATOMIC);
306 if (!skb) {
307 ncsi_free_request(nr);
308 return NULL;
309 }
310
311 nr->cmd = skb;
312 skb_reserve(skb, hlen);
313 skb_reset_network_header(skb);
314
315 skb->dev = dev;
316 skb->protocol = htons(ETH_P_NCSI);
317
318 return nr;
319 }
320
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all at lists.01.org
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