linux/net
Eric Dumazet 614e8316aa tcp: add support for usec resolution in TCP TS values
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[1] Unfortunately RFC 7323 5.5 (Outdated Timestamps) suggests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 <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-10-23 09:35:01 +01:00
..
6lowpan
9p net: annotate data-races around sock->ops 2023-08-09 15:32:43 -07:00
802
8021q Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-08-18 12:44:56 -07:00
appletalk appletalk: remove special handling code for ipddp 2023-10-13 17:59:32 -07:00
atm net: atm: Remove redundant check. 2023-10-23 08:45:25 +01:00
ax25 net: implement lockless SO_PRIORITY 2023-10-01 19:09:54 +01:00
batman-adv Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-08-24 10:51:39 -07:00
bluetooth Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-10-19 13:29:01 -07:00
bpf bpf: Prevent inlining of bpf_fentry_test7() 2023-08-30 08:36:17 +02:00
bpfilter
bridge netfilter: bridge: convert br_netfilter to NF_DROP_REASON 2023-10-18 10:26:43 +02:00
caif sock: Remove ->sendpage*() in favour of sendmsg(MSG_SPLICE_PAGES) 2023-06-24 15:50:13 -07:00
can Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-10-12 17:07:34 -07:00
ceph Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-10-19 13:29:01 -07:00
core Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-10-19 13:29:01 -07:00
dcb net: dcb: choose correct policy to parse DCB_ATTR_BCN 2023-08-01 21:07:46 -07:00
dccp tcp: record last received ipv6 flowlabel 2023-10-10 10:02:59 +02:00
devlink devlink: convert most of devlink_fmsg_*() to return void 2023-10-20 11:34:51 +01:00
dns_resolver
dsa net: dsa: remove dsa_port_phylink_validate() 2023-10-11 10:06:05 +01:00
ethernet
ethtool ethtool: untangle the linkmode and ethtool headers 2023-10-20 12:47:33 +01:00
handshake handshake: Fix sign of key_serial_t fields 2023-10-02 12:34:21 -07:00
hsr net: hsr: Add __packed to struct hsr_sup_tlv. 2023-09-18 08:26:19 +01:00
ieee802154 sysctl-6.6-rc1 2023-08-29 17:39:15 -07:00
ife
ipv4 tcp: add support for usec resolution in TCP TS values 2023-10-23 09:35:01 +01:00
ipv6 tcp: add support for usec resolution in TCP TS values 2023-10-23 09:35:01 +01:00
iucv
kcm kcm: Fix error handling for SOCK_DGRAM in kcm_sendmsg(). 2023-09-14 10:43:51 +02:00
key Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-08-18 12:44:56 -07:00
l2tp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-10-05 13:16:47 -07:00
l3mdev
lapb
llc net/llc/llc_conn.c: fix 4 instances of -Wmissing-variable-declarations 2023-08-09 15:34:28 -07:00
mac80211 wifi: mac80211: fix error path key leak 2023-10-11 16:36:14 +02:00
mac802154 Core WPAN changes: 2023-06-24 15:41:46 -07:00
mctp mctp: perform route lookups under a RCU read-side lock 2023-10-10 19:43:22 -07:00
mpls networking: Update to register_net_sysctl_sz 2023-08-15 15:26:18 -07:00
mptcp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-10-19 13:29:01 -07:00
ncsi ncsi: Propagate carrier gain/loss events to the NCSI controller 2023-09-18 07:06:05 +01:00
netfilter tcp: introduce tcp_clock_ms() 2023-10-23 09:35:01 +01:00
netlabel netlabel: Remove unused declaration netlbl_cipsov4_doi_free() 2023-08-02 12:28:22 -07:00
netlink netlink: add variable-length / auto integers 2023-10-20 11:43:35 +01:00
netrom net: implement lockless SO_PRIORITY 2023-10-01 19:09:54 +01:00
nfc nfc: nci: fix possible NULL pointer dereference in send_acknowledge() 2023-10-16 17:34:53 -07:00
nsh
openvswitch net: openvswitch: Annotate struct mask_array with __counted_by 2023-10-17 13:56:03 +02:00
packet Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-10-12 17:07:34 -07:00
phonet sock: Remove ->sendpage*() in favour of sendmsg(MSG_SPLICE_PAGES) 2023-06-24 15:50:13 -07:00
psample
qrtr net: qrtr: Handle IPCR control port format of older targets 2023-07-17 09:02:30 +01:00
rds net: prevent address rewrite in kernel_bind() 2023-10-01 19:31:29 +01:00
rfkill net: rfkill: reduce data->mtx scope in rfkill_fop_open 2023-10-11 16:55:10 +02:00
rose net: implement lockless SO_PRIORITY 2023-10-01 19:09:54 +01:00
rxrpc Networking changes for 6.5. 2023-06-28 16:43:10 -07:00
sched Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-10-19 13:29:01 -07:00
sctp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-10-05 13:16:47 -07:00
smc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-10-19 13:29:01 -07:00
strparser
sunrpc SUNRPC/TLS: Lock the lower_xprt during the tls handshake 2023-09-27 15:16:40 -04:00
switchdev net: switchdev: Add a helper to replay objects on a bridge port 2023-07-21 08:54:03 +01:00
tipc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-10-05 13:16:47 -07:00
tls Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-10-19 13:29:01 -07:00
unix bpf: Implement cgroup sockaddr hooks for unix sockets 2023-10-11 17:27:47 -07:00
vmw_vsock vsock: enable setting SO_ZEROCOPY 2023-10-15 13:19:42 +01:00
wireless Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-10-19 13:29:01 -07:00
x25 net: implement lockless SO_PRIORITY 2023-10-01 19:09:54 +01:00
xdp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-10-12 17:07:34 -07:00
xfrm Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-10-19 13:29:01 -07:00
compat.c
devres.c
Kconfig net: add skb_segment kunit test 2023-10-11 10:39:01 +01:00
Kconfig.debug
Makefile
socket.c net: prevent address rewrite in kernel_bind() 2023-10-01 19:31:29 +01:00
sysctl_net.c sysctl: Add size to register_net_sysctl function 2023-08-15 15:26:17 -07:00