net: ncsi: Adding padding bytes in the payload
Subsystems (3)
PATCH 1/1 net: ncsi: Adding padding bytes in the payload
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.
--- net/ncsi/ncsi-cmd.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-)
net/ncsi/ncsi-cmd.c +17 -4
@@ -214,11 +214,19 @@ static int ncsi_cmd_handler_oem(struct sk_buff *skb,struct ncsi_cmd_oem_pkt *cmd;unsigned int len; +/* NC-SI spec 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 +280,7 @@ 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 +290,18 @@ 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 follwoing payload is +* aligned to 32bit 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
Dear Kumar,
Thank you for your patch.
Nit: Could you please use the imperative mood in the commit message summary:
Quoted 1 line
net: ncsi: Add padding bytes in the payload
Or more descriptive:
Quoted 1 line
net: ncsi: Padd payload to be 32-bit aligned to fix dropped packets
Am 12.10.21 um 08:22 schrieb 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.
How can this be reproduced?
Quoted 11 lines
Signed-off-by Kumar Thangavel <[email protected]>--- net/ncsi/ncsi-cmd.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-)net/ncsi/ncsi-cmd.c +0
-0
net/ncsi/ncsi-cmd.c static int ncsi_cmd_handler_oem(struct sk_buff *skb, · line 217
Quoted 4 lines
net/ncsi/ncsi-cmd.c +1
-0@@ -214,11 +214,19 @@ static int ncsi_cmd_handler_oem(struct sk_buff *skb,struct ncsi_cmd_oem_pkt *cmd;unsigned int len; +/* NC-SI spec requires payload to be padded with 0
It?d be great, if you included the specification version, and section if the requirement.
net/ncsi/ncsi-cmd.c static int ncsi_cmd_handler_oem(struct sk_buff *skb, · line 222
Quoted 5 lines
net/ncsi/ncsi-cmd.c +5
-0+* to 32-bit boundary before the checksum field. +* Ensure the padding bytes are accounted for in +* skb allocation +*/ +
Please remove the blank line.
Quoted 21 lines
net/ncsi/ncsi-cmd.c +5
-2+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 +280,7 @@ 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 static struct ncsi_request *ncsi_alloc_command(struct ncsi_cmd_arg *nca) · line 293
Quoted 4 lines
net/ncsi/ncsi-cmd.c +1
-0@@ -281,14 +290,18 @@ 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 follwoing payload is
following
net/ncsi/ncsi-cmd.c static struct ncsi_request *ncsi_alloc_command(struct ncsi_cmd_arg *nca) · line 294
Quoted 1 line
net/ncsi/ncsi-cmd.c +1
-0+* aligned to 32bit boundary.
32-bit
Quoted 6 lines
net/ncsi/ncsi-cmd.c +0
-1* 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 )
net/ncsi/ncsi-cmd.c static struct ncsi_request *ncsi_alloc_command(struct ncsi_cmd_arg *nca) · line 307
Quoted 10 lines
net/ncsi/ncsi-cmd.c +4
-1+ + payload =ALIGN (nca->payload,4 ); +if (payload <26 ) len +=26 ;else - len += nca->payload; + len += payload;/* Allocate skb */ skb =alloc_skb (len,GFP_ATOMIC );
Besides the nits, this looks fine to me.
Kind regards,
Paul
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.
Can you help us review this by pointing out where this is described in the NCSI spec?
We've been running this code for a number of years now and I wonder why this hasn't been a problem so far.
Cheers,
Joel
Quoted 65 lines
Signed-off-by Kumar Thangavel <[email protected]>--- net/ncsi/ncsi-cmd.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-)net/ncsi/ncsi-cmd.c +17
-5@@ -214,11 +214,19 @@ static int ncsi_cmd_handler_oem(struct sk_buff *skb,struct ncsi_cmd_oem_pkt *cmd;unsigned int len; +/* NC-SI spec 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 +280,7 @@ 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 +290,18 @@ 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 follwoing payload is +* aligned to 32bit 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 ); --2.17.1
Samuel Mendoza-Jonas
maintainerQuoted 11 lines · Joel Stanley
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 5 lines
Can you help us review this by pointing out where this is described in the NCSI spec?
We've been running this code for a number of years now and I wonder why this hasn't been a problem so far.
I'm assuming this is referencing section 8.2.2.2:
If the payload is present and does not end on a 32-bit boundary, one to three padding bytes equal to 0x00 shall be present to align the checksum field to a 32-bit boundary.
But I'm also surprised this hasn't caused issues so far if we've been getting it wrong. Is there an example that reproduces the issue?
Cheers,
Sam
Quoted 76 lines
Cheers,
Joel
Quoted 71 lines
Signed-off-by Kumar Thangavel <[email protected]>---
?net/ncsi/ncsi-cmd.c | 21 +++++++++++++++++----
?1 file changed, 17 insertions(+), 4 deletions(-)net/ncsi/ncsi-cmd.c +9
-1@@ -214,11 +214,19 @@ static int ncsi_cmd_handler_oem(struct sk_buff *skb, ??????? struct ncsi_cmd_oem_pkt *cmd; ??????? unsigned int len; +?????? /* NC-SI spec 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);net/ncsi/ncsi-cmd.c +1
-0@@ -272,6 +280,7 @@ 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 +290,18 @@ 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 follwoing payload is
+??????? * aligned to 32bit 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);
--
2.17.1
PATCH 1/1 net: ncsi: Adding padding bytes in the payload
Thanks for your review. Please find my response below.
Fixed all the comments. I will update the next patchset.
Thanks,
Kumar.
Quoted 15 lines · Samuel Mendoza-Jonas
Quoted 14 lines · Joel Stanley
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.
Can you help us review this by pointing out where this is described in the NCSI spec?
Quoted 8 lines
Quoted 2 lines
We've been running this code for a number of years now and I wonder why this hasn't been a problem so far.
I'm assuming this is referencing section 8.2.2.2:
If the payload is present and does not end on a 32-bit boundary, one to three padding bytes equal to0x00shall be present to align the checksum field to a 32-bit boundary.
Kumar : Yes. In the NC-SI spec, section 8.2.2.2 represents a 32-bit boundary.
If it does not end on a 32-bit boundary, padding bytes can be
added.
Quoted 4 lines
But I'm also surprised this hasn't caused issues so far if we've been getting it wrong. Is there an example that reproduces the issue?
Kumar : We have a use case of NIC firmware update in our system which is pldm based and the transport layer is NC-SI based on RBT.
Sending some pldm based commands to NIC. In that, some of
the commands failed because of a payload size less than 32.
So, Added padding bytes to align the 32-bit boundary and
issues got resolved.
Quoted 83 lines
Cheers,
SamQuoted 76 lines
Cheers,
Joel
Quoted 71 lines
Signed-off-by Kumar Thangavel <[email protected]>--- net/ncsi/ncsi-cmd.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-)net/ncsi/ncsi-cmd.c +10
-2@@ -214,11 +214,19 @@ static int ncsi_cmd_handler_oem(struct sk_buff *skb, struct ncsi_cmd_oem_pkt *cmd;unsigned int len; +/* NC-SI spec 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);net/ncsi/ncsi-cmd.c +1
-0@@ -272,6 +280,7 @@ 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 +290,18 @@ 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 follwoing
payload is
+ * aligned to 32bit 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;net/ncsi/ncsi-cmd.c +4
-3-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 ); --2.17.1