net: qualcomm: rmnet: add tx packets aggregation

Add tx packets aggregation.

Bidirectional TCP throughput tests through iperf with low-cat
Thread-x based modems revelead performance issues both in

net: qualcomm: rmnet: add tx packets aggregation

Add tx packets aggregation.

Bidirectional TCP throughput tests through iperf with low-cat
Thread-x based modems revelead performance issues both in tx
and rx.

The Windows driver does not show this issue: inspecting USB
packets revealed that the only notable change is the driver
enabling tx packets aggregation.

Tx packets aggregation is by default disabled and can be enabled
by increasing the value of ETHTOOL_A_COALESCE_TX_MAX_AGGR_FRAMES.

The maximum aggregated size is by default set to a reasonably low
value in order to support the majority of modems.

This implementation is based on patches available in Code Aurora
repositories (msm kernel) whose main authors are

Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Sean Tranchetti <stranche@codeaurora.org>

Signed-off-by: Daniele Palmas <dnlplm@gmail.com>
Reviewed-by: Subash Abhinov Kasiviswanathan <quic_subashab@quicinc.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: Use skb_put_zero() to simplify code

Use skb_put_zero() instead of hand-writing it. This saves a few lines of
code and is more readable.

Signed-off-by: Christophe JAILLET <chri

net: qualcomm: rmnet: Use skb_put_zero() to simplify code

Use skb_put_zero() instead of hand-writing it. This saves a few lines of
code and is more readable.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: fix two pointer math bugs

We recently changed these two pointers from void pointers to struct
pointers and it breaks the pointer math so now the "txphdr" points
beyond the end

net: qualcomm: rmnet: fix two pointer math bugs

We recently changed these two pointers from void pointers to struct
pointers and it breaks the pointer math so now the "txphdr" points
beyond the end of the buffer.

Fixes: 56a967c4f7e5 ("net: qualcomm: rmnet: Remove some unneeded casts")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: Remove some unneeded casts

Remove the explicit casts in the checksum complement functions
and pass the actual protocol specific headers instead.

Signed-off-by: Subash Abhinov

net: qualcomm: rmnet: Remove some unneeded casts

Remove the explicit casts in the checksum complement functions
and pass the actual protocol specific headers instead.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: always expose a few functions

A recent change tidied up some conditional code, avoiding the use of
some #ifdefs. Unfortunately, if CONFIG_IPV6 was not enabled, it
meant that t

net: qualcomm: rmnet: always expose a few functions

A recent change tidied up some conditional code, avoiding the use of
some #ifdefs. Unfortunately, if CONFIG_IPV6 was not enabled, it
meant that two functions were referenced but never defined.

The easiest fix is to just define stubs for these functions if
CONFIG_IPV6 is not defined. This will soon be simplified further
by some other development in the works...

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 75db5b07f8c39 ("net: qualcomm: rmnet: eliminate some ifdefs")
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: IPv6 payload length is simple

We don't support any extension headers for IPv6 packets. Extension
headers therefore contribute 0 bytes to the payload length. As a
result we ca

net: qualcomm: rmnet: IPv6 payload length is simple

We don't support any extension headers for IPv6 packets. Extension
headers therefore contribute 0 bytes to the payload length. As a
result we can just use the IPv6 payload length as the length used to
compute the pseudo header checksum for both UDP and TCP messages.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: drop some unary NOTs

We compare a payload checksum with a pseudo checksum value for
equality in rmnet_map_ipv4_dl_csum_trailer(). Both of those values
are computed with a unar

net: qualcomm: rmnet: drop some unary NOTs

We compare a payload checksum with a pseudo checksum value for
equality in rmnet_map_ipv4_dl_csum_trailer(). Both of those values
are computed with a unary NOT (~) operation. The result of the
comparison is the same if we omit that NOT for both values.

Remove these operations in rmnet_map_ipv6_dl_csum_trailer() also.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: trailer value is a checksum

The csum_value field in the rmnet_map_dl_csum_trailer structure is a
"real" Internet checksum. It is a 16 bit value, in big endian format,
which re

net: qualcomm: rmnet: trailer value is a checksum

The csum_value field in the rmnet_map_dl_csum_trailer structure is a
"real" Internet checksum. It is a 16 bit value, in big endian format,
which represents an inverted ones' complement sum over pairs of bytes.

Make that clear by changing its type to __sum16.

This makes a typecast in rmnet_map_ipv4_dl_csum_trailer() and
another in rmnet_map_ipv6_dl_csum_trailer() unnecessary.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: remove unneeded code

The previous patch makes rmnet_map_ipv4_dl_csum_trailer() return
early with an error if it is determined that the computed checksum
for the IP payload does

net: qualcomm: rmnet: remove unneeded code

The previous patch makes rmnet_map_ipv4_dl_csum_trailer() return
early with an error if it is determined that the computed checksum
for the IP payload does not match what was expected.

If the computed checksum *does* match the expected value, the IP
payload (i.e., the transport message), can be considered good.
There is no need to do any further processing of the message.

This means a big block of code is unnecessary for validating the
transport checksum value, and can be removed.

Make comparable changes in rmnet_map_ipv6_dl_csum_trailer().

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: return earlier for bad checksum

In rmnet_map_ipv4_dl_csum_trailer(), if the sum of the trailer
checksum and the pseudo checksum is non-zero, checksum validation
has failed. We

net: qualcomm: rmnet: return earlier for bad checksum

In rmnet_map_ipv4_dl_csum_trailer(), if the sum of the trailer
checksum and the pseudo checksum is non-zero, checksum validation
has failed. We can return an error as soon as we know that.

We can do the same thing in rmnet_map_ipv6_dl_csum_trailer().

Add some comments that explain where we're headed.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: show that an intermediate sum is zero

This patch simply demonstrates that a checksum value computed when
verifying an offloaded transport checksum value for both IPv4 and
IPv6

net: qualcomm: rmnet: show that an intermediate sum is zero

This patch simply demonstrates that a checksum value computed when
verifying an offloaded transport checksum value for both IPv4 and
IPv6 is (normally) 0. It can be squashed into the next patch.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: rearrange some NOTs

With the ones' complement arithmetic, the sum of two negated values
is equal to the negation of the sum of the two original values [1].
Rearrange the calcul

net: qualcomm: rmnet: rearrange some NOTs

With the ones' complement arithmetic, the sum of two negated values
is equal to the negation of the sum of the two original values [1].
Rearrange the calculation ip6_payload_sum using this property.

[1] https://tools.ietf.org/html/rfc1071

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: remove some local variables

In rmnet_map_ipv4_dl_csum_trailer(), remove the "csum_temp" and
"addend" local variables, and simplify a few lines of code.

Remove the "csum_temp",

net: qualcomm: rmnet: remove some local variables

In rmnet_map_ipv4_dl_csum_trailer(), remove the "csum_temp" and
"addend" local variables, and simplify a few lines of code.

Remove the "csum_temp", "csum_value", "ip6_hdr_csum", and "addend"
local variables in rmnet_map_ipv6_dl_csum_trailer(), and simplify a
few lines of code there as well.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: avoid unnecessary IPv6 byte-swapping

In the previous patch IPv4 download checksum offload code was
updated to avoid unnecessary byte swapping, based on properties of
the Intern

net: qualcomm: rmnet: avoid unnecessary IPv6 byte-swapping

In the previous patch IPv4 download checksum offload code was
updated to avoid unnecessary byte swapping, based on properties of
the Internet checksum algorithm. This patch makes comparable
changes to the IPv6 download checksum offload handling.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: avoid unnecessary byte-swapping

Internet checksums are used for IPv4 header checksum, as well as TCP
segment and UDP datagram checksums. Such a checksum represents the
negated

net: qualcomm: rmnet: avoid unnecessary byte-swapping

Internet checksums are used for IPv4 header checksum, as well as TCP
segment and UDP datagram checksums. Such a checksum represents the
negated sum of adjacent pairs of bytes, using ones' complement
arithmetic.

One property of the Internet checkum is byte order independence [1].
Specifically, the sum of byte-swapped pairs is equal to the result
of byte swapping the sum of those same pairs when not byte-swapped.

So for example if a, b, c, d, y, and z are hexadecimal digits, and
PLUS represents ones' complement addition:
If: ab PLUS cd = yz
Then: ba PLUS dc = zy

For this reason, there is no need to swap the order of bytes in the
checksum value held in a message header, nor the one in the QMAPv4
trailer, in order to operate on them.

In other words, we can determine whether the hardware-computed
checksum matches the one in the message header without any byte
swaps.

(This patch leaves in place all existing type casts.)

[1] https://tools.ietf.org/html/rfc1071

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: clarify a bit of code

In rmnet_map_ipv6_dl_csum_trailer() there is an especially involved
line of code that determines the ones' complement sum of the IPv6
packet header (in ho

net: qualcomm: rmnet: clarify a bit of code

In rmnet_map_ipv6_dl_csum_trailer() there is an especially involved
line of code that determines the ones' complement sum of the IPv6
packet header (in host byte order). Simplify that by storing the
result of computing just the header checksum in a local variable,
then using that in the original assignment.

Use the size of the IPv6 header structure as the number of bytes to
checksum, rather than computing the offset to the transport header.
And use ip_fast_csum() rather than ipa_compute_csum(), knowing that
the size of an IPv6 header (40 bytes) is a multiple of 4 bytes
greater than 16.

Add some comments to match rmnet_map_ipv4_dl_csum_trailer().

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: IPv4 header has zero checksum

In rmnet_map_ipv4_dl_csum_trailer(), an illegal checksum subtraction
is done, subtracting hdr_csum (in host byte order) from csum_value (in
networ

net: qualcomm: rmnet: IPv4 header has zero checksum

In rmnet_map_ipv4_dl_csum_trailer(), an illegal checksum subtraction
is done, subtracting hdr_csum (in host byte order) from csum_value (in
network byte order). Despite being illegal, it generally works,
because it turns out the value subtracted is (or should be) always 0,
which has the same representation in either byte order.

Doing illegal operations is not good form though, so fix this by
verifying the IP header checksum early in that function. If its
checksum is non-zero, the packet will be bad, so just return an
error. This will cause the packet to passed to the IP layer where
it can be dropped.

Thereafter, there is no need subtract the IP header checksum from
the checksum value in the trailer because we know it is zero.
Add a comment explaining this.

This type of packet error is different from other types, so add a
new statistics counter to track this condition.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: simplify rmnet_map_get_csum_field()

The checksum fields of the TCP and UDP header structures already
have type __sum16. We don't support any other protocol headers, so
we can

net: qualcomm: rmnet: simplify rmnet_map_get_csum_field()

The checksum fields of the TCP and UDP header structures already
have type __sum16. We don't support any other protocol headers, so
we can simplify rmnet_map_get_csum_field(), getting rid of the local
variable entirely and just returning the appropriate address.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: get rid of some local variables

The value passed as an argument to rmnet_map_ipv4_ul_csum_header()
is always an IPv4 header. Rather than using a local variable, just
have the

net: qualcomm: rmnet: get rid of some local variables

The value passed as an argument to rmnet_map_ipv4_ul_csum_header()
is always an IPv4 header. Rather than using a local variable, just
have the type of the argument reflect the proper type.

In rmnet_map_ipv6_ul_csum_header() things are defined a little
differently, but make the same basic change there.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: eliminate some ifdefs

If IPV6 is not enabled in the kernel configuration, the RMNet
checksum code indicates a buffer containing an IPv6 packet is not
supported. The same thing

net: qualcomm: rmnet: eliminate some ifdefs

If IPV6 is not enabled in the kernel configuration, the RMNet
checksum code indicates a buffer containing an IPv6 packet is not
supported. The same thing happens if a buffer contains something
other than an IPv4 or IPv6 packet.

We can rearrange things a bit in two functions so that some #ifdef
calls can simply be eliminated.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: use ip_is_fragment()

In rmnet_map_ipv4_dl_csum_trailer() use ip_is_fragment() to
determine whether a socket buffer contains a packet fragment.

Signed-off-by: Alex Elder <elder

net: qualcomm: rmnet: use ip_is_fragment()

In rmnet_map_ipv4_dl_csum_trailer() use ip_is_fragment() to
determine whether a socket buffer contains a packet fragment.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: ethernet: rmnet: Restructure if checks to avoid uninitialized warning

Clang warns that proto in rmnet_map_v5_checksum_uplink_packet() might be
used uninitialized:

drivers/net/ethernet/qualcomm

net: ethernet: rmnet: Restructure if checks to avoid uninitialized warning

Clang warns that proto in rmnet_map_v5_checksum_uplink_packet() might be
used uninitialized:

drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c:283:14: warning:
variable 'proto' is used uninitialized whenever 'if' condition is false
[-Wsometimes-uninitialized]
} else if (skb->protocol == htons(ETH_P_IPV6)) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c:295:36: note:
uninitialized use occurs here
check = rmnet_map_get_csum_field(proto, trans);
^~~~~
drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c:283:10: note:
remove the 'if' if its condition is always true
} else if (skb->protocol == htons(ETH_P_IPV6)) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c:270:11: note:
initialize the variable 'proto' to silence this warning
u8 proto;
^
= '\0'
1 warning generated.

This is technically a false positive because there is an if statement
above this one that checks skb->protocol for not being either
ETH_P_IP{,V6}. However, it is more obvious to sink that into the if
statement as an else branch, which makes the code clearer and fixes the
warning.

At the same time, move the "IS_ENABLED(CONFIG_IPV6)" into the else if
condition so that the else branch of the preprocessor conditional can
be shared, since there is no build failure with CONFIG_IPV6 disabled.

Fixes: b6e5d27e32ef ("net: ethernet: rmnet: Add support for MAPv5 egress packets")
Link: https://github.com/ClangBuiltLinux/linux/issues/1390
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: ethernet: rmnet: Add support for MAPv5 egress packets

Adding support for MAPv5 egress packets.

This involves adding the MAPv5 header and setting the csum_valid_required
in the checksum header

net: ethernet: rmnet: Add support for MAPv5 egress packets

Adding support for MAPv5 egress packets.

This involves adding the MAPv5 header and setting the csum_valid_required
in the checksum header to request HW compute the checksum.

Corresponding stats are incremented based on whether the checksum is
computed in software or HW.

New stat has been added which represents the count of packets whose
checksum is calculated by the HW.

Signed-off-by: Sharath Chandra Vurukala <sharathv@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: ethernet: rmnet: Support for ingress MAPv5 checksum offload

Adding support for processing of MAPv5 downlink packets.
It involves parsing the Mapv5 packet and checking the csum header
to know wh

net: ethernet: rmnet: Support for ingress MAPv5 checksum offload

Adding support for processing of MAPv5 downlink packets.
It involves parsing the Mapv5 packet and checking the csum header
to know whether the hardware has validated the checksum and is
valid or not.

Based on the checksum valid bit the corresponding stats are
incremented and skb->ip_summed is marked either CHECKSUM_UNNECESSARY
or left as CHEKSUM_NONE to let network stack revalidate the checksum
and update the respective snmp stats.

Current MAPV1 header has been modified, the reserved field in the
Mapv1 header is now used for next header indication.

Signed-off-by: Sharath Chandra Vurukala <sharathv@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: qualcomm: rmnet: don't use C bit-fields in rmnet checksum header

Replace the use of C bit-fields in the rmnet_map_ul_csum_header
structure with a single two-byte (big endian) structure member,

net: qualcomm: rmnet: don't use C bit-fields in rmnet checksum header

Replace the use of C bit-fields in the rmnet_map_ul_csum_header
structure with a single two-byte (big endian) structure member,
and use masks to encode or get values within it. The content of
these fields can be accessed using simple bitwise AND and OR
operations on the (host byte order) value of the new structure
member.

Previously rmnet_map_ipv4_ul_csum_header() would update C bit-field
values in host byte order, then forcibly fix their byte order using
a combination of byte swap operations and types.

Instead, just compute the value that needs to go into the new
structure member and save it with a simple byte-order conversion.

Make similar simplifications in rmnet_map_ipv6_ul_csum_header().

Finally, in rmnet_map_checksum_uplink_packet() a set of assignments
zeroes every field in the upload checksum header. Replace that with
a single memset() operation.

Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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