linux-toradex.git/include/linux/tcp.h, branch v6.8-rc2

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2023-12-08T01:53:17+00:00

Cross-merge networking fixes after downstream PR.

Conflicts:

drivers/net/ethernet/stmicro/stmmac/dwmac5.c
drivers/net/ethernet/stmicro/stmmac/dwmac5.h
drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
drivers/net/ethernet/stmicro/stmmac/hwif.h
  37e4b8df27bc ("net: stmmac: fix FPE events losing")
  c3f3b97238f6 ("net: stmmac: Refactor EST implementation")
https://lore.kernel.org/all/20231206110306.01e91114@canb.auug.org.au/

Adjacent changes:

net/ipv4/tcp_ao.c
  9396c4ee93f9 ("net/tcp: Don't store TCP-AO maclen on reqsk")
  7b0f570f879a ("tcp: Move TCP-AO bits from cookie_v[46]_check() to tcp_ao_syncookie().")

Signed-off-by: Jakub Kicinski

net/tcp: Don't store TCP-AO maclen on reqsk

2023-12-06T11:36:56+00:00

This extra check doesn't work for a handshake when SYN segment has
(current_key.maclen != rnext_key.maclen). It could be amended to
preserve rnext_key.maclen instead of current_key.maclen, but that
requires a lookup on listen socket.

Originally, this extra maclen check was introduced just because it was
cheap. Drop it and convert tcp_request_sock::maclen into boolean
tcp_request_sock::used_tcp_ao.

Fixes: 06b22ef29591 ("net/tcp: Wire TCP-AO to request sockets")
Signed-off-by: Dmitry Safonov 
Reviewed-by: Eric Dumazet 
Signed-off-by: Paolo Abeni

tcp: reorganize tcp_sock fast path variables

2023-12-06T04:16:05+00:00

The variables are organized according in the following way:

- TX read-mostly hotpath cache lines
- TXRX read-mostly hotpath cache lines
- RX read-mostly hotpath cache lines
- TX read-write hotpath cache line
- TXRX read-write hotpath cache line
- RX read-write hotpath cache line

Fastpath cachelines end after rcvq_space.

Cache line boundaries are enforced only between read-mostly and
read-write. That is, if read-mostly tx cachelines bleed into
read-mostly txrx cachelines, we do not care. We care about the
boundaries between read and write cachelines because we want
to prevent false sharing.

Fast path variables span cache lines before change: 12
Fast path variables span cache lines after change: 8

Suggested-by: Eric Dumazet 
Reviewed-by: Wei Wang 
Signed-off-by: Coco Li 
Reviewed-by: Eric Dumazet 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20231204201232.520025-3-lixiaoyan@google.com
Signed-off-by: Jakub Kicinski

tcp: fix fastopen code vs usec TS

2023-11-03T09:16:42+00:00

After blamed commit, TFO client-ack-dropped-then-recovery-ms-timestamps
packetdrill test failed.

David Morley and Neal Cardwell started investigating and Neal pointed
that we had :

tcp_conn_request()
  tcp_try_fastopen()
   -> tcp_fastopen_create_child
     -> child = inet_csk(sk)->icsk_af_ops->syn_recv_sock()
       -> tcp_create_openreq_child()
          -> copy req_usec_ts from req:
          newtp->tcp_usec_ts = treq->req_usec_ts;
          // now the new TFO server socket always does usec TS, no matter
          // what the route options are...
  send_synack()
    -> tcp_make_synack()
        // disable tcp_rsk(req)->req_usec_ts if route option is not present:
        if (tcp_rsk(req)->req_usec_ts < 0)
                tcp_rsk(req)->req_usec_ts = dst_tcp_usec_ts(dst);

tcp_conn_request() has the initial dst, we can initialize
tcp_rsk(req)->req_usec_ts there instead of later in send_synack();

This means tcp_rsk(req)->req_usec_ts can be a boolean.

Many thanks to David an Neal for their help.

Fixes: 614e8316aa4c ("tcp: add support for usec resolution in TCP TS values")
Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-lkp/202310302216.f79d78bc-oliver.sang@intel.com
Suggested-by: Neal Cardwell 
Signed-off-by: Eric Dumazet 
Cc: David Morley 
Acked-by: Neal Cardwell 
Signed-off-by: David S. Miller

net/tcp: Wire TCP-AO to request sockets

2023-10-27T09:35:45+00:00

Now when the new request socket is created from the listening socket,
it's recorded what MKT was used by the peer. tcp_rsk_used_ao() is
a new helper for checking if TCP-AO option was used to create the
request socket.
tcp_ao_copy_all_matching() will copy all keys that match the peer on the
request socket, as well as preparing them for the usage (creating
traffic keys).

Co-developed-by: Francesco Ruggeri 
Signed-off-by: Francesco Ruggeri 
Co-developed-by: Salam Noureddine 
Signed-off-by: Salam Noureddine 
Signed-off-by: Dmitry Safonov 
Acked-by: David Ahern 
Signed-off-by: David S. Miller

net/tcp: Add TCP-AO sign to twsk

2023-10-27T09:35:44+00:00

Add support for sockets in time-wait state.
ao_info as well as all keys are inherited on transition to time-wait
socket. The lifetime of ao_info is now protected by ref counter, so
that tcp_ao_destroy_sock() will destruct it only when the last user is
gone.

Co-developed-by: Francesco Ruggeri 
Signed-off-by: Francesco Ruggeri 
Co-developed-by: Salam Noureddine 
Signed-off-by: Salam Noureddine 
Signed-off-by: Dmitry Safonov 
Acked-by: David Ahern 
Signed-off-by: David S. Miller

net/tcp: Add TCP-AO config and structures

2023-10-27T09:35:44+00:00

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

Co-developed-by: Francesco Ruggeri 
Signed-off-by: Francesco Ruggeri 
Co-developed-by: Salam Noureddine 
Signed-off-by: Salam Noureddine 
Signed-off-by: Dmitry Safonov 
Acked-by: David Ahern 
Signed-off-by: David S. Miller

tcp: add support for usec resolution in TCP TS values

2023-10-23T08:35:01+00:00

Back in 2015, Van Jacobson suggested to use usec resolution in TCP TS values.
This has been implemented in our private kernels.

Goals were :

1) better observability of delays in networking stacks.
2) better disambiguation of events based on TSval/ecr values.
3) building block for congestion control modules needing usec resolution.

Back then we implemented a schem based on private SYN options
to negotiate the feature.

For upstream submission, we chose to use a route attribute,
because this feature is probably going to be used in private
networks [1] [2].

ip route add 10/8 ... features tcp_usec_ts

Note that RFC 7323 recommends a
  "timestamp clock frequency in the range 1 ms to 1 sec per tick.",
but also mentions
  "the maximum acceptable clock frequency is one tick every 59 ns."

[1] Unfortunately RFC 7323 5.5 (Outdated Timestamps) suggests
to invalidate TS.Recent values after a flow was idle for more
than 24 days. This is the part making usec_ts a problem
for peers following this recommendation for long living
idle flows.

[2] Attempts to standardize usec ts went nowhere:

https://www.ietf.org/proceedings/97/slides/slides-97-tcpm-tcp-options-for-low-latency-00.pdf
https://datatracker.ietf.org/doc/draft-wang-tcpm-low-latency-opt/

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

tcp: add RTAX_FEATURE_TCP_USEC_TS

2023-10-23T08:35:01+00:00

This new dst feature flag will be used to allow TCP to use usec
based timestamps instead of msec ones.

ip route .... feature tcp_usec_ts

Also document that RTAX_FEATURE_SACK and RTAX_FEATURE_TIMESTAMP
are unused.

RTAX_FEATURE_ALLFRAG is also going away soon.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

tcp: new TCP_INFO stats for RTO events

2023-09-16T12:42:34+00:00

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 
Signed-off-by: Neal Cardwell 
Signed-off-by: Yuchung Cheng 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller