tcp: support TCP_DELACK_MAX_US for set/getsockopt use

Support adjusting/reading delayed ack max for socket level by using
set/getsockopt().

This option aligns with TCP_BPF_DELACK_MAX usage. Conside

tcp: support TCP_DELACK_MAX_US for set/getsockopt use

Support adjusting/reading delayed ack max for socket level by using
set/getsockopt().

This option aligns with TCP_BPF_DELACK_MAX usage. Considering that bpf
option was implemented before this patch, so we need to use a standalone
new option for pure tcp set/getsockopt() use.

Add WRITE_ONCE/READ_ONCE() to prevent data-race if setsockopt()
happens to write one value to icsk_delack_max while icsk_delack_max is
being read.

Signed-off-by: Jason Xing <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

tcp: support TCP_RTO_MIN_US for set/getsockopt use

Support adjusting/reading RTO MIN for socket level by using set/getsockopt().

This new option has the same effect as TCP_BPF_RTO_MIN, which means

tcp: support TCP_RTO_MIN_US for set/getsockopt use

Support adjusting/reading RTO MIN for socket level by using set/getsockopt().

This new option has the same effect as TCP_BPF_RTO_MIN, which means it
doesn't affect RTAX_RTO_MIN usage (by using ip route...). Considering that
bpf option was implemented before this patch, so we need to use a standalone
new option for pure tcp set/getsockopt() use.

When the socket is created, its icsk_rto_min is set to the default
value that is controlled by sysctl_tcp_rto_min_us. Then if application
calls setsockopt() with TCP_RTO_MIN_US flag to pass a valid value, then
icsk_rto_min will be overridden in jiffies unit.

This patch adds WRITE_ONCE/READ_ONCE to avoid data-race around
icsk_rto_min.

Signed-off-by: Jason Xing <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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tcp: extend TCP flags to allow AE bit/ACE field

With AccECN, there's one additional TCP flag to be used (AE)
and ACE field that overloads the definition of AE, CWR, and
ECE flags. As tcp_flags was p

tcp: extend TCP flags to allow AE bit/ACE field

With AccECN, there's one additional TCP flag to be used (AE)
and ACE field that overloads the definition of AE, CWR, and
ECE flags. As tcp_flags was previously only 1 byte, the
byte-order stuff needs to be added to it's handling.

Signed-off-by: Ilpo Järvinen <[email protected]>
Signed-off-by: Chia-Yu Chang <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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tcp: add the ability to control max RTO

Currently, TCP stack uses a constant (120 seconds)
to limit the RTO value exponential growth.

Some applications want to set a lower value.

Add TCP_RTO_MAX_M

tcp: add the ability to control max RTO

Currently, TCP stack uses a constant (120 seconds)
to limit the RTO value exponential growth.

Some applications want to set a lower value.

Add TCP_RTO_MAX_MS socket option to set a value (in ms)
between 1 and 120 seconds.

It is discouraged to change the socket rto max on a live
socket, as it might lead to unexpected disconnects.

Following patch is adding a netns sysctl to control the
default value at socket creation time.

Signed-off-by: Eric Dumazet <[email protected]>
Reviewed-by: Jason Xing <[email protected]>
Reviewed-by: Neal Cardwell <[email protected]>
Reviewed-by: Kuniyuki Iwashima <[email protected]>
Signed-off-by: Paolo Abeni <[email protected]>

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tcp: socket option to check for MPTCP fallback to TCP

A way for an application to know if an MPTCP connection fell back to TCP
is to use getsockopt(MPTCP_INFO) and look for errors. The issue with
th

tcp: socket option to check for MPTCP fallback to TCP

A way for an application to know if an MPTCP connection fell back to TCP
is to use getsockopt(MPTCP_INFO) and look for errors. The issue with
this technique is that the same errors -- EOPNOTSUPP (IPv4) and
ENOPROTOOPT (IPv6) -- are returned if there was a fallback, *or* if the
kernel doesn't support this socket option. The userspace then has to
look at the kernel version to understand what the errors mean.

It is not clean, and it doesn't take into account older kernels where
the socket option has been backported. A cleaner way would be to expose
this info to the TCP socket level. In case of MPTCP socket where no
fallback happened, the socket options for the TCP level will be handled
in MPTCP code, in mptcp_getsockopt_sol_tcp(). If not, that will be in
TCP code, in do_tcp_getsockopt(). So MPTCP simply has to set the value
1, while TCP has to set 0.

If the socket option is not supported, one of these two errors will be
reported:
- EOPNOTSUPP (95 - Operation not supported) for MPTCP sockets
- ENOPROTOOPT (92 - Protocol not available) for TCP sockets, e.g. on the
socket received after an 'accept()', when the client didn't request to
use MPTCP: this socket will be a TCP one, even if the listen socket
was an MPTCP one.

With this new option, the kernel can return a clear answer to both "Is
this kernel new enough to tell me the fallback status?" and "If it is
new enough, is it currently a TCP or MPTCP socket?" questions, while not
breaking the previous method.

Acked-by: Mat Martineau <[email protected]>
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Link: https://lore.kernel.org/r/20240509-upstream-net-next-20240509-mptcp-tcp_is_mptcp-v1-1-f846df999202@kernel.org
Signed-off-by: Jakub Kicinski <[email protected]>

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net/tcp: Add TCP_AO_REPAIR

Add TCP_AO_REPAIR setsockopt(), getsockopt(). They let a user to repair
TCP-AO ISNs/SNEs. Also let the user hack around when (tp->repair) is on
and add ao_info on a socket

net/tcp: Add TCP_AO_REPAIR

Add TCP_AO_REPAIR setsockopt(), getsockopt(). They let a user to repair
TCP-AO ISNs/SNEs. Also let the user hack around when (tp->repair) is on
and add ao_info on a socket in any supported state.
As SNEs now can be read/written at any moment, use
WRITE_ONCE()/READ_ONCE() to set/read them.

Signed-off-by: Dmitry Safonov <[email protected]>
Acked-by: David Ahern <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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net/tcp: Allow asynchronous delete for TCP-AO keys (MKTs)

Delete becomes very, very fast - almost free, but after setsockopt()
syscall returns, the key is still alive until next RCU grace period.
Wh

net/tcp: Allow asynchronous delete for TCP-AO keys (MKTs)

Delete becomes very, very fast - almost free, but after setsockopt()
syscall returns, the key is still alive until next RCU grace period.
Which is fine for listen sockets as userspace needs to be aware of
setsockopt(TCP_AO) and accept() race and resolve it with verification
by getsockopt() after TCP connection was accepted.

The benchmark results (on non-loaded box, worse with more RCU work pending):
> ok 33 Worst case delete 16384 keys: min=5ms max=10ms mean=6.93904ms stddev=0.263421
> ok 34 Add a new key 16384 keys: min=1ms max=4ms mean=2.17751ms stddev=0.147564
> ok 35 Remove random-search 16384 keys: min=5ms max=10ms mean=6.50243ms stddev=0.254999
> ok 36 Remove async 16384 keys: min=0ms max=0ms mean=0.0296107ms stddev=0.0172078

Co-developed-by: Francesco Ruggeri <[email protected]>
Signed-off-by: Francesco Ruggeri <[email protected]>
Co-developed-by: Salam Noureddine <[email protected]>
Signed-off-by: Salam Noureddine <[email protected]>
Signed-off-by: Dmitry Safonov <[email protected]>
Acked-by: David Ahern <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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net/tcp: Add TCP-AO getsockopt()s

Introduce getsockopt(TCP_AO_GET_KEYS) that lets a user get TCP-AO keys
and their properties from a socket. The user can provide a filter
to match the specific key t

net/tcp: Add TCP-AO getsockopt()s

Introduce getsockopt(TCP_AO_GET_KEYS) that lets a user get TCP-AO keys
and their properties from a socket. The user can provide a filter
to match the specific key to be dumped or ::get_all = 1 may be
used to dump all keys in one syscall.

Add another getsockopt(TCP_AO_INFO) for providing per-socket/per-ao_info
stats: packet counters, Current_key/RNext_key and flags like
::ao_required and ::accept_icmps.

Co-developed-by: Francesco Ruggeri <[email protected]>
Signed-off-by: Francesco Ruggeri <[email protected]>
Co-developed-by: Salam Noureddine <[email protected]>
Signed-off-by: Salam Noureddine <[email protected]>
Signed-off-by: Dmitry Safonov <[email protected]>
Acked-by: David Ahern <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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net/tcp: Add option for TCP-AO to (not) hash header

Provide setsockopt() key flag that makes TCP-AO exclude hashing TCP
header for peers that match the key. This is needed for interraction
with midd

net/tcp: Add option for TCP-AO to (not) hash header

Provide setsockopt() key flag that makes TCP-AO exclude hashing TCP
header for peers that match the key. This is needed for interraction
with middleboxes that may change TCP options, see RFC5925 (9.2).

Co-developed-by: Francesco Ruggeri <[email protected]>
Signed-off-by: Francesco Ruggeri <[email protected]>
Co-developed-by: Salam Noureddine <[email protected]>
Signed-off-by: Salam Noureddine <[email protected]>
Signed-off-by: Dmitry Safonov <[email protected]>
Acked-by: David Ahern <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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net/tcp: Ignore specific ICMPs for TCP-AO connections

Similarly to IPsec, RFC5925 prescribes:
">> A TCP-AO implementation MUST default to ignore incoming ICMPv4
messages of Type 3 (destination u

net/tcp: Ignore specific ICMPs for TCP-AO connections

Similarly to IPsec, RFC5925 prescribes:
">> A TCP-AO implementation MUST default to ignore incoming ICMPv4
messages of Type 3 (destination unreachable), Codes 2-4 (protocol
unreachable, port unreachable, and fragmentation needed -- ’hard
errors’), and ICMPv6 Type 1 (destination unreachable), Code 1
(administratively prohibited) and Code 4 (port unreachable) intended
for connections in synchronized states (ESTABLISHED, FIN-WAIT-1, FIN-
WAIT-2, CLOSE-WAIT, CLOSING, LAST-ACK, TIME-WAIT) that match MKTs."

A selftest (later in patch series) verifies that this attack is not
possible in this TCP-AO implementation.

Co-developed-by: Francesco Ruggeri <[email protected]>
Signed-off-by: Francesco Ruggeri <[email protected]>
Co-developed-by: Salam Noureddine <[email protected]>
Signed-off-by: Salam Noureddine <[email protected]>
Signed-off-by: Dmitry Safonov <[email protected]>
Acked-by: David Ahern <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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net/tcp: Add TCP-AO segments counters

Introduce segment counters that are useful for troubleshooting/debugging
as well as for writing tests.
Now there are global snmp counters as well as per-socket

net/tcp: Add TCP-AO segments counters

Introduce segment counters that are useful for troubleshooting/debugging
as well as for writing tests.
Now there are global snmp counters as well as per-socket and per-key.

Co-developed-by: Francesco Ruggeri <[email protected]>
Signed-off-by: Francesco Ruggeri <[email protected]>
Co-developed-by: Salam Noureddine <[email protected]>
Signed-off-by: Salam Noureddine <[email protected]>
Signed-off-by: Dmitry Safonov <[email protected]>
Acked-by: David Ahern <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net/tcp: Introduce TCP_AO setsockopt()s

Add 3 setsockopt()s:
1. TCP_AO_ADD_KEY to add a new Master Key Tuple (MKT) on a socket
2. TCP_AO_DEL_KEY to delete present MKT from a socket
3. TCP_AO_INFO to

net/tcp: Introduce TCP_AO setsockopt()s

Add 3 setsockopt()s:
1. TCP_AO_ADD_KEY to add a new Master Key Tuple (MKT) on a socket
2. TCP_AO_DEL_KEY to delete present MKT from a socket
3. TCP_AO_INFO to change flags, Current_key/RNext_key on a TCP-AO sk

Userspace has to introduce keys on every socket it wants to use TCP-AO
option on, similarly to TCP_MD5SIG/TCP_MD5SIG_EXT.
RFC5925 prohibits definition of MKTs that would match the same peer,
so do sanity checks on the data provided by userspace. Be as
conservative as possible, including refusal of defining MKT on
an established connection with no AO, removing the key in-use and etc.

(1) and (2) are to be used by userspace key manager to add/remove keys.
(3) main purpose is to set RNext_key, which (as prescribed by RFC5925)
is the KeyID that will be requested in TCP-AO header from the peer to
sign their segments with.

At this moment the life of ao_info ends in tcp_v4_destroy_sock().

Co-developed-by: Francesco Ruggeri <[email protected]>
Signed-off-by: Francesco Ruggeri <[email protected]>
Co-developed-by: Salam Noureddine <[email protected]>
Signed-off-by: Salam Noureddine <[email protected]>
Signed-off-by: Dmitry Safonov <[email protected]>
Acked-by: David Ahern <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net/tcp: Add TCP-AO config and structures

Introduce new kernel config option and common structures as well as
helpers to be used by TCP-AO code.

Co-developed-by: Francesco Ruggeri <fruggeri@arista.

net/tcp: Add TCP-AO config and structures

Introduce new kernel config option and common structures as well as
helpers to be used by TCP-AO code.

Co-developed-by: Francesco Ruggeri <[email protected]>
Signed-off-by: Francesco Ruggeri <[email protected]>
Co-developed-by: Salam Noureddine <[email protected]>
Signed-off-by: Salam Noureddine <[email protected]>
Signed-off-by: Dmitry Safonov <[email protected]>
Acked-by: David Ahern <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

tcp: add TCPI_OPT_USEC_TS

Add the ability to report in tcp_info.tcpi_options if
a flow is using usec resolution in TCP TS val.

Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David

tcp: add TCPI_OPT_USEC_TS

Add the ability to report in tcp_info.tcpi_options if
a flow is using usec resolution in TCP TS val.

Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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tcp: new TCP_INFO stats for RTO events

The 2023 SIGCOMM paper "Improving Network Availability with Protective
ReRoute" has indicated Linux TCP's RTO-triggered txhash rehashing can
effectively reduce

tcp: new TCP_INFO stats for RTO events

The 2023 SIGCOMM paper "Improving Network Availability with Protective
ReRoute" has indicated Linux TCP's RTO-triggered txhash rehashing can
effectively reduce application disruption during outages. To better
measure the efficacy of this feature, this patch adds three more
detailed stats during RTO recovery and exports via TCP_INFO.
Applications and monitoring systems can leverage this data to measure
the network path diversity and end-to-end repair latency during network
outages to improve their network infrastructure.

The following counters are added to tcp_sock in order to track RTO
events over the lifetime of a TCP socket.

1. u16 total_rto - Counts the total number of RTO timeouts.
2. u16 total_rto_recoveries - Counts the total number of RTO recoveries.
3. u32 total_rto_time - Counts the total time spent (ms) in RTO
recoveries. (time spent in CA_Loss and
CA_Recovery states)

To compute total_rto_time, we add a new u32 rto_stamp field to
tcp_sock. rto_stamp records the start timestamp (ms) of the last RTO
recovery (CA_Loss).

Corresponding fields are also added to the tcp_info struct.

Signed-off-by: Aananth V <[email protected]>
Signed-off-by: Neal Cardwell <[email protected]>
Signed-off-by: Yuchung Cheng <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

tcp: add rcv_wnd and plb_rehash to TCP_INFO

rcv_wnd can be useful to diagnose TCP performance where receiver window
becomes the bottleneck. rehash reports the PLB and timeout triggered
rehash attemp

tcp: add rcv_wnd and plb_rehash to TCP_INFO

rcv_wnd can be useful to diagnose TCP performance where receiver window
becomes the bottleneck. rehash reports the PLB and timeout triggered
rehash attempts by the TCP connection.

Signed-off-by: Mubashir Adnan Qureshi <[email protected]>
Signed-off-by: Yuchung Cheng <[email protected]>
Signed-off-by: Neal Cardwell <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

tcp: add u32 counter in tcp_sock and an SNMP counter for PLB

A u32 counter is added to tcp_sock for counting the number of PLB
triggered rehashes for a TCP connection. An SNMP counter is also
added

tcp: add u32 counter in tcp_sock and an SNMP counter for PLB

A u32 counter is added to tcp_sock for counting the number of PLB
triggered rehashes for a TCP connection. An SNMP counter is also
added to count overall PLB triggered rehash events for a host. These
counters are hooked up to PLB implementation for DCTCP.

TCP_NLA_REHASH is added to SCM_TIMESTAMPING_OPT_STATS that reports
the rehash attempts triggered due to PLB or timeouts. This gives
a historical view of sustained congestion or timeouts experienced
by the TCP connection.

Signed-off-by: Mubashir Adnan Qureshi <[email protected]>
Signed-off-by: Yuchung Cheng <[email protected]>
Signed-off-by: Neal Cardwell <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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tcp: Sanitize CMSG flags and reserved args in tcp_zerocopy_receive.

Explicitly define reserved field and require it and any subsequent
fields to be zero-valued for now. Additionally, limit the valid

tcp: Sanitize CMSG flags and reserved args in tcp_zerocopy_receive.

Explicitly define reserved field and require it and any subsequent
fields to be zero-valued for now. Additionally, limit the valid CMSG
flags that tcp_zerocopy_receive accepts.

Fixes: 7eeba1706eba ("tcp: Add receive timestamp support for receive zerocopy.")
Signed-off-by: Arjun Roy <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: Soheil Hassas Yeganeh <[email protected]>
Suggested-by: David Ahern <[email protected]>
Suggested-by: Leon Romanovsky <[email protected]>
Suggested-by: Jakub Kicinski <[email protected]>
Acked-by: Jakub Kicinski <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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tcp: Add receive timestamp support for receive zerocopy.

tcp_recvmsg() uses the CMSG mechanism to receive control information
like packet receive timestamps. This patch adds CMSG fields to
struct tc

tcp: Add receive timestamp support for receive zerocopy.

tcp_recvmsg() uses the CMSG mechanism to receive control information
like packet receive timestamps. This patch adds CMSG fields to
struct tcp_zerocopy_receive, and provides receive timestamps
if available to the user.

Signed-off-by: Arjun Roy <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

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tcp: add TTL to SCM_TIMESTAMPING_OPT_STATS

This patch adds TCP_NLA_TTL to SCM_TIMESTAMPING_OPT_STATS that exports
the time-to-live or hop limit of the latest incoming packet with
SCM_TSTAMP_ACK. The

tcp: add TTL to SCM_TIMESTAMPING_OPT_STATS

This patch adds TCP_NLA_TTL to SCM_TIMESTAMPING_OPT_STATS that exports
the time-to-live or hop limit of the latest incoming packet with
SCM_TSTAMP_ACK. The value exported may not be from the packet that acks
the sequence when incoming packets are aggregated. Exporting the
time-to-live or hop limit value of incoming packets helps to estimate
the hop count of the path of the flow that may change over time.

Signed-off-by: Yousuk Seung <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: Neal Cardwell <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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Fix whitespace in uapi/linux/tcp.h.

List of things fixed:
- Two of the socket options were idented with spaces instead of tabs.
- Trailing whitespace in some lines.
- Improper spacing around p

Fix whitespace in uapi/linux/tcp.h.

List of things fixed:
- Two of the socket options were idented with spaces instead of tabs.
- Trailing whitespace in some lines.
- Improper spacing around parenthesis caught by checkpatch.pl.
- Mix of space and tabs in tcp_word_hdr union.

Signed-off-by: Danilo Carvalho <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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net-zerocopy: Defer vm zap unless actually needed.

Zapping pages is required only if we are calling vm_insert_page into a
region where pages had previously been mapped. Receive zerocopy allows
reusi

net-zerocopy: Defer vm zap unless actually needed.

Zapping pages is required only if we are calling vm_insert_page into a
region where pages had previously been mapped. Receive zerocopy allows
reusing such regions, and hitherto called zap_page_range() before
calling vm_insert_page() in that range.

zap_page_range() can also be triggered from userspace with
madvise(MADV_DONTNEED). If userspace is configured to call this before
reusing a segment, or if there was nothing mapped at this virtual
address to begin with, we can avoid calling zap_page_range() under the
socket lock. That said, if userspace does not do that, then we are
still responsible for calling zap_page_range().

This patch adds a flag that the user can use to hint to the kernel
that a zap is not required. If the flag is not set, or if an older
user application does not have a flags field at all, then the kernel
calls zap_page_range as before. Also, if the flag is set but a zap is
still required, the kernel performs that zap as necessary. Thus
incorrectly indicating that a zap can be avoided does not change the
correctness of operation. It also increases the batchsize for
vm_insert_pages and prefetches the page struct for the batch since
we're about to bump the refcount.

An alternative mechanism could be to not have a flag, assume by
default a zap is not needed, and fall back to zapping if needed.
However, this would harm performance for older applications for which
a zap is necessary, and thus we implement it with an explicit flag
so newer applications can opt in.

When using RPC-style traffic with medium sized (tens of KB) RPCs, this
change yields an efficency improvement of about 30% for QPS/CPU usage.

Signed-off-by: Arjun Roy <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: Soheil Hassas Yeganeh <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

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net-zerocopy: Copy straggler unaligned data for TCP Rx. zerocopy.

When TCP receive zerocopy does not successfully map the entire
requested space, it outputs a 'hint' that the caller should recvmsg()

net-zerocopy: Copy straggler unaligned data for TCP Rx. zerocopy.

When TCP receive zerocopy does not successfully map the entire
requested space, it outputs a 'hint' that the caller should recvmsg().

Augment zerocopy to accept a user buffer that it tries to copy this
hint into - if it is possible to copy the entire hint, it will do so.
This elides a recvmsg() call for received traffic that isn't exactly
page-aligned in size.

This was tested with RPC-style traffic of arbitrary sizes. Normally,
each received message required at least one getsockopt() call, and one
recvmsg() call for the remaining unaligned data.

With this change, almost all of the recvmsg() calls are eliminated,
leading to a savings of about 25%-50% in number of system calls
for RPC-style workloads.

Signed-off-by: Arjun Roy <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: Soheil Hassas Yeganeh <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

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tcp: add earliest departure time to SCM_TIMESTAMPING_OPT_STATS

This change adds TCP_NLA_EDT to SCM_TIMESTAMPING_OPT_STATS that reports
the earliest departure time(EDT) of the timestamped skb. By tra

tcp: add earliest departure time to SCM_TIMESTAMPING_OPT_STATS

This change adds TCP_NLA_EDT to SCM_TIMESTAMPING_OPT_STATS that reports
the earliest departure time(EDT) of the timestamped skb. By tracking EDT
values of the skb from different timestamps, we can observe when and how
much the value changed. This allows to measure the precise delay
injected on the sender host e.g. by a bpf-base throttler.

Signed-off-by: Yousuk Seung <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Acked-by: Neal Cardwell <[email protected]>
Acked-by: Soheil Hassas Yeganeh <[email protected]>
Acked-by: Yuchung Cheng <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

tcp: add bytes not sent to SCM_TIMESTAMPING_OPT_STATS

Add TCP_NLA_BYTES_NOTSENT to SCM_TIMESTAMPING_OPT_STATS that reports
bytes in the write queue but not sent. This is the same metric as
what is e

tcp: add bytes not sent to SCM_TIMESTAMPING_OPT_STATS

Add TCP_NLA_BYTES_NOTSENT to SCM_TIMESTAMPING_OPT_STATS that reports
bytes in the write queue but not sent. This is the same metric as
what is exported with tcp_info.tcpi_notsent_bytes.

Signed-off-by: Yousuk Seung <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Acked-by: Soheil Hassas Yeganeh <[email protected]>
Acked-by: Yuchung Cheng <[email protected]>
Acked-by: Neal Cardwell <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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