Adding documentation explaining the new MAPv4/v5 packet formats
and the corresponding checksum offload headers.
Acked-by: Subash Abhinov Kasiviswanathan <[email protected]>
Acked-by: Alex Elder <[email protected]>
Signed-off-by: Sharath Chandra Vurukala <[email protected]>
---
.../device_drivers/cellular/qualcomm/rmnet.rst | 126 +++++++++++++++++++--
1 file changed, 114 insertions(+), 12 deletions(-)
diff --git a/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst b/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst
index 70643b5..4118384 100644
--- a/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst
+++ b/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst
@@ -27,34 +27,136 @@ these MAP frames and send them to appropriate PDN's.
2. Packet format
================
-a. MAP packet (data / control)
+a. MAP packet v1 (data / control)
-MAP header has the same endianness of the IP packet.
+MAP header fields are in big endian format.
Packet format::
- Bit 0 1 2-7 8 - 15 16 - 31
+ Bit 0 1 2-7 8-15 16-31
Function Command / Data Reserved Pad Multiplexer ID Payload length
- Bit 32 - x
- Function Raw Bytes
+
+ Bit 32-x
+ Function Raw bytes
Command (1)/ Data (0) bit value is to indicate if the packet is a MAP command
-or data packet. Control packet is used for transport level flow control. Data
+or data packet. Command packet is used for transport level flow control. Data
packets are standard IP packets.
-Reserved bits are usually zeroed out and to be ignored by receiver.
+Reserved bits must be zero when sent and ignored when received.
-Padding is number of bytes to be added for 4 byte alignment if required by
-hardware.
+Padding is the number of bytes to be appended to the payload to
+ensure 4 byte alignment.
Multiplexer ID is to indicate the PDN on which data has to be sent.
Payload length includes the padding length but does not include MAP header
length.
-b. MAP packet (command specific)::
+b. Map packet v4 (data / control)
+
+MAP header fields are in big endian format.
+
+Packet format::
+
+ Bit 0 1 2-7 8-15 16-31
+ Function Command / Data Reserved Pad Multiplexer ID Payload length
+
+ Bit 32-(x-33) (x-32)-x
+ Function Raw bytes Checksum offload header
+
+Command (1)/ Data (0) bit value is to indicate if the packet is a MAP command
+or data packet. Command packet is used for transport level flow control. Data
+packets are standard IP packets.
+
+Reserved bits must be zero when sent and ignored when received.
+
+Padding is the number of bytes to be appended to the payload to
+ensure 4 byte alignment.
+
+Multiplexer ID is to indicate the PDN on which data has to be sent.
+
+Payload length includes the padding length but does not include MAP header
+length.
+
+Checksum offload header, has the information about the checksum processing done
+by the hardware.Checksum offload header fields are in big endian format.
+
+Packet format::
+
+ Bit 0-14 15 16-31
+ Function Reserved Valid Checksum start offset
+
+ Bit 31-47 48-64
+ Function Checksum length Checksum value
+
+Reserved bits must be zero when sent and ignored when received.
+
+Valid bit indicates whether the partial checksum is calculated and is valid.
+Set to 1, if its is valid. Set to 0 otherwise.
+
+Padding is the number of bytes to be appended to the payload to
+ensure 4 byte alignment.
+
+Checksum start offset, Indicates the offset in bytes from the beginning of the
+IP header, from which modem computed checksum.
+
+Checksum length is the Length in bytes starting from CKSUM_START_OFFSET,
+over which checksum is computed.
+
+Checksum value, indicates the checksum computed.
+
+c. MAP packet v5 (data / control)
+
+MAP header fields are in big endian format.
+
+Packet format::
+
+ Bit 0 1 2-7 8-15 16-31
+ Function Command / Data Next header Pad Multiplexer ID Payload length
+
+ Bit 32-x
+ Function Raw bytes
+
+Command (1)/ Data (0) bit value is to indicate if the packet is a MAP command
+or data packet. Command packet is used for transport level flow control. Data
+packets are standard IP packets.
+
+Next header is used to indicate the presence of another header, currently is
+limited to checksum header.
+
+Padding is the number of bytes to be appended to the payload to
+ensure 4 byte alignment.
+
+Multiplexer ID is to indicate the PDN on which data has to be sent.
+
+Payload length includes the padding length but does not include MAP header
+length.
+
+d. Checksum offload header v5
+
+Checksum offload header fields are in big endian format.
+
+ Bit 0 - 6 7 8-15 16-31
+ Function Header Type Next Header Checksum Valid Reserved
+
+Header Type is to indicate the type of header, this usually is set to CHECKSUM
+
+Header types
+= ==========================================
+0 Reserved
+1 Reserved
+2 checksum header
+
+Checksum Valid is to indicate whether the header checksum is valid. Value of 1
+implies that checksum is calculated on this packet and is valid, value of 0
+indicates that the calculated packet checksum is invalid.
+
+Reserved bits must be zero when sent and ignored when received.
+
+e. MAP packet v1/v5 (command specific)::
- Bit 0 1 2-7 8 - 15 16 - 31
+ Bit 0 1 2-7 8 - 15 16 - 31
Function Command Reserved Pad Multiplexer ID Payload length
Bit 32 - 39 40 - 45 46 - 47 48 - 63
Function Command name Reserved Command Type Reserved
@@ -74,7 +176,7 @@ Command types
3 is for error during processing of commands
= ==========================================
-c. Aggregation
+f. Aggregation
Aggregation is multiple MAP packets (can be data or command) delivered to
rmnet in a single linear skb. rmnet will process the individual
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
On 4/23/21 7:19 AM, Sharath Chandra Vurukala wrote:
> Adding documentation explaining the new MAPv4/v5 packet formats
> and the corresponding checksum offload headers.
>
> Acked-by: Subash Abhinov Kasiviswanathan <[email protected]>
> Acked-by: Alex Elder <[email protected]>
> Signed-off-by: Sharath Chandra Vurukala <[email protected]>
You indicated I acknowledged this, and I didn't have any
other real input, so this looks good.
-Alex
> ---
> .../device_drivers/cellular/qualcomm/rmnet.rst | 126 +++++++++++++++++++--
> 1 file changed, 114 insertions(+), 12 deletions(-)
>
> diff --git a/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst b/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst
> index 70643b5..4118384 100644
> --- a/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst
> +++ b/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst
> @@ -27,34 +27,136 @@ these MAP frames and send them to appropriate PDN's.
> 2. Packet format
> ================
>
> -a. MAP packet (data / control)
> +a. MAP packet v1 (data / control)
>
> -MAP header has the same endianness of the IP packet.
> +MAP header fields are in big endian format.
>
> Packet format::
>
> - Bit 0 1 2-7 8 - 15 16 - 31
> + Bit 0 1 2-7 8-15 16-31
> Function Command / Data Reserved Pad Multiplexer ID Payload length
> - Bit 32 - x
> - Function Raw Bytes
> +
> + Bit 32-x
> + Function Raw bytes
>
> Command (1)/ Data (0) bit value is to indicate if the packet is a MAP command
> -or data packet. Control packet is used for transport level flow control. Data
> +or data packet. Command packet is used for transport level flow control. Data
> packets are standard IP packets.
>
> -Reserved bits are usually zeroed out and to be ignored by receiver.
> +Reserved bits must be zero when sent and ignored when received.
>
> -Padding is number of bytes to be added for 4 byte alignment if required by
> -hardware.
> +Padding is the number of bytes to be appended to the payload to
> +ensure 4 byte alignment.
>
> Multiplexer ID is to indicate the PDN on which data has to be sent.
>
> Payload length includes the padding length but does not include MAP header
> length.
>
> -b. MAP packet (command specific)::
> +b. Map packet v4 (data / control)
> +
> +MAP header fields are in big endian format.
> +
> +Packet format::
> +
> + Bit 0 1 2-7 8-15 16-31
> + Function Command / Data Reserved Pad Multiplexer ID Payload length
> +
> + Bit 32-(x-33) (x-32)-x
> + Function Raw bytes Checksum offload header
> +
> +Command (1)/ Data (0) bit value is to indicate if the packet is a MAP command
> +or data packet. Command packet is used for transport level flow control. Data
> +packets are standard IP packets.
> +
> +Reserved bits must be zero when sent and ignored when received.
> +
> +Padding is the number of bytes to be appended to the payload to
> +ensure 4 byte alignment.
> +
> +Multiplexer ID is to indicate the PDN on which data has to be sent.
> +
> +Payload length includes the padding length but does not include MAP header
> +length.
> +
> +Checksum offload header, has the information about the checksum processing done
> +by the hardware.Checksum offload header fields are in big endian format.
> +
> +Packet format::
> +
> + Bit 0-14 15 16-31
> + Function Reserved Valid Checksum start offset
> +
> + Bit 31-47 48-64
> + Function Checksum length Checksum value
> +
> +Reserved bits must be zero when sent and ignored when received.
> +
> +Valid bit indicates whether the partial checksum is calculated and is valid.
> +Set to 1, if its is valid. Set to 0 otherwise.
> +
> +Padding is the number of bytes to be appended to the payload to
> +ensure 4 byte alignment.
> +
> +Checksum start offset, Indicates the offset in bytes from the beginning of the
> +IP header, from which modem computed checksum.
> +
> +Checksum length is the Length in bytes starting from CKSUM_START_OFFSET,
> +over which checksum is computed.
> +
> +Checksum value, indicates the checksum computed.
> +
> +c. MAP packet v5 (data / control)
> +
> +MAP header fields are in big endian format.
> +
> +Packet format::
> +
> + Bit 0 1 2-7 8-15 16-31
> + Function Command / Data Next header Pad Multiplexer ID Payload length
> +
> + Bit 32-x
> + Function Raw bytes
> +
> +Command (1)/ Data (0) bit value is to indicate if the packet is a MAP command
> +or data packet. Command packet is used for transport level flow control. Data
> +packets are standard IP packets.
> +
> +Next header is used to indicate the presence of another header, currently is
> +limited to checksum header.
> +
> +Padding is the number of bytes to be appended to the payload to
> +ensure 4 byte alignment.
> +
> +Multiplexer ID is to indicate the PDN on which data has to be sent.
> +
> +Payload length includes the padding length but does not include MAP header
> +length.
> +
> +d. Checksum offload header v5
> +
> +Checksum offload header fields are in big endian format.
> +
> + Bit 0 - 6 7 8-15 16-31
> + Function Header Type Next Header Checksum Valid Reserved
> +
> +Header Type is to indicate the type of header, this usually is set to CHECKSUM
> +
> +Header types
> += ==========================================
> +0 Reserved
> +1 Reserved
> +2 checksum header
> +
> +Checksum Valid is to indicate whether the header checksum is valid. Value of 1
> +implies that checksum is calculated on this packet and is valid, value of 0
> +indicates that the calculated packet checksum is invalid.
> +
> +Reserved bits must be zero when sent and ignored when received.
> +
> +e. MAP packet v1/v5 (command specific)::
>
> - Bit 0 1 2-7 8 - 15 16 - 31
> + Bit 0 1 2-7 8 - 15 16 - 31
> Function Command Reserved Pad Multiplexer ID Payload length
> Bit 32 - 39 40 - 45 46 - 47 48 - 63
> Function Command name Reserved Command Type Reserved
> @@ -74,7 +176,7 @@ Command types
> 3 is for error during processing of commands
> = ==========================================
>
> -c. Aggregation
> +f. Aggregation
>
> Aggregation is multiple MAP packets (can be data or command) delivered to
> rmnet in a single linear skb. rmnet will process the individual
>