linux/net/ipv4
Yuchung Cheng 336c39a031 tcp: undo init congestion window on false SYNACK timeout
Linux implements RFC6298 and use an initial congestion window
of 1 upon establishing the connection if the SYNACK packet is
retransmitted 2 or more times. In cellular networks SYNACK timeouts
are often spurious if the wireless radio was dormant or idle. Also
some network path is longer than the default SYNACK timeout. In
both cases falsely starting with a minimal cwnd are detrimental
to performance.

This patch avoids doing so when the final ACK's TCP timestamp
indicates the original SYNACK was delivered. It remembers the
original SYNACK timestamp when SYNACK timeout has occurred and
re-uses the function to detect spurious SYN timeout conveniently.

Note that a server may receives multiple SYNs from and immediately
retransmits SYNACKs without any SYNACK timeout. This often happens
on when the client SYNs have timed out due to wireless delay
above. In this case since the server will still use the default
initial congestion (e.g. 10) because tp->undo_marker is reset in
tcp_init_metrics(). This is an intentional design because packets
are not lost but delayed.

This patch only covers regular TCP passive open. Fast Open is
supported in the next patch.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-01 11:47:54 -04:00
..
bpfilter net: bpfilter: dont use module_init in non-modular code 2019-04-22 21:50:54 -07:00
netfilter netfilter: x_tables: merge ip and ipv6 masquerade modules 2019-04-11 20:59:29 +02:00
af_inet.c net: rework SIOCGSTAMP ioctl handling 2019-04-19 14:07:40 -07:00
ah4.c
arp.c
cipso_ipv4.c netlabel: fix out-of-bounds memory accesses 2019-02-27 21:45:24 -08:00
datagram.c
devinet.c netlink: make validation more configurable for future strictness 2019-04-27 17:07:21 -04:00
esp4_offload.c xfrm: store xfrm_mode directly, not its address 2019-04-08 09:15:28 +02:00
esp4.c esp: Skip TX bytes accounting when sending from a request socket 2019-01-28 11:20:58 +01:00
fib_frontend.c netlink: make validation more configurable for future strictness 2019-04-27 17:07:21 -04:00
fib_lookup.h ipv4: Add fib_nh_common to fib_result 2019-04-03 21:50:20 -07:00
fib_notifier.c
fib_rules.c ipv4: fib_rules: Fix possible infinite loop in fib_empty_table 2018-12-30 12:57:04 -08:00
fib_semantics.c netlink: make nla_nest_start() add NLA_F_NESTED flag 2019-04-27 17:03:44 -04:00
fib_trie.c ipv4: Add fib_nh_common to fib_result 2019-04-03 21:50:20 -07:00
fou.c genetlink: optionally validate strictly/dumps 2019-04-27 17:07:22 -04:00
gre_demux.c net: ip_gre: use erspan key field for tunnel lookup 2019-01-22 11:52:17 -08:00
gre_offload.c
icmp.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-03-02 12:54:35 -08:00
igmp.c net: remove unneeded switch fall-through 2019-02-21 13:48:00 -08:00
inet_connection_sock.c ipv4: Prepare rtable for IPv6 gateway 2019-04-08 15:22:40 -07:00
inet_diag.c inet_diag: fix reporting cgroup classid and fallback to priority 2019-02-12 13:35:57 -05:00
inet_fragment.c net: remove unused struct inet_frag_queue.fragments field 2019-02-26 08:27:05 -08:00
inet_hashtables.c net: dccp: fix kernel crash on module load 2018-12-24 15:27:56 -08:00
inet_timewait_sock.c
inetpeer.c net: ipv4: use a dedicated counter for icmp_v4 redirect packets 2019-02-08 21:50:15 -08:00
ip_forward.c ipv4: Prepare rtable for IPv6 gateway 2019-04-08 15:22:40 -07:00
ip_fragment.c net: remove unused struct inet_frag_queue.fragments field 2019-02-26 08:27:05 -08:00
ip_gre.c net: ip_gre: fix possible use-after-free in erspan_rcv 2019-04-08 16:16:47 -07:00
ip_input.c vrf: check accept_source_route on the original netdevice 2019-04-01 10:44:58 -07:00
ip_options.c vrf: check accept_source_route on the original netdevice 2019-04-01 10:44:58 -07:00
ip_output.c ipv4: Add helpers for neigh lookup for nexthop 2019-04-08 15:22:41 -07:00
ip_sockglue.c ip: on queued skb use skb_header_pointer instead of pskb_may_pull 2019-01-10 09:27:20 -05:00
ip_tunnel_core.c netlink: make validation more configurable for future strictness 2019-04-27 17:07:21 -04:00
ip_tunnel.c iptunnel: NULL pointer deref for ip_md_tunnel_xmit 2019-03-06 10:43:06 -08:00
ip_vti.c xfrm: store xfrm_mode directly, not its address 2019-04-08 09:15:28 +02:00
ipcomp.c
ipconfig.c ipconfig: add carrier_timeout kernel parameter 2019-02-01 15:24:13 -08:00
ipip.c ip_tunnel: Add tnl_update_pmtu in ip_md_tunnel_xmit 2019-01-26 09:43:03 -08:00
ipmr_base.c netlink: make nla_nest_start() add NLA_F_NESTED flag 2019-04-27 17:03:44 -04:00
ipmr.c netlink: make validation more configurable for future strictness 2019-04-27 17:07:21 -04:00
Kconfig xfrm: make xfrm modes builtin 2019-04-08 09:15:17 +02:00
Makefile xfrm: make xfrm modes builtin 2019-04-08 09:15:17 +02:00
metrics.c net: Add extack argument to ip_fib_metrics_init 2018-11-06 15:00:45 -08:00
netfilter.c netfilter: ipv4: remove useless export_symbol 2019-01-28 11:32:58 +01:00
netlink.c ipv4: Add ICMPv6 support when parse route ipproto 2019-03-01 16:41:27 -08:00
ping.c
proc.c tcp: implement coalescing on backlog queue 2018-11-30 13:26:54 -08:00
protocol.c fou, fou6: ICMP error handlers for FoU and GUE 2018-11-08 17:13:08 -08:00
raw_diag.c
raw.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-12-20 11:53:36 -08:00
route.c netlink: make validation more configurable for future strictness 2019-04-27 17:07:21 -04:00
syncookies.c tcp: free request sock directly upon TFO or syncookies error 2019-03-19 14:13:01 -07:00
sysctl_net_ipv4.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-25 23:52:29 -04:00
tcp_bbr.c tcp_bbr: adapt cwnd based on ack aggregation estimation 2019-01-24 22:27:27 -08:00
tcp_bic.c
tcp_bpf.c bpf: sk_msg, sock{map|hash} redirect through ULP 2018-12-20 23:47:09 +01:00
tcp_cdg.c
tcp_cong.c
tcp_cubic.c
tcp_dctcp.c dctcp: more accurate tracking of packets delivery 2019-04-11 21:31:03 -07:00
tcp_dctcp.h
tcp_diag.c
tcp_fastopen.c
tcp_highspeed.c
tcp_htcp.c
tcp_hybla.c
tcp_illinois.c
tcp_input.c tcp: undo init congestion window on false SYNACK timeout 2019-05-01 11:47:54 -04:00
tcp_ipv4.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-05 14:14:19 -07:00
tcp_lp.c
tcp_metrics.c tcp: undo initial congestion window on false SYN timeout 2019-05-01 11:47:54 -04:00
tcp_minisocks.c tcp: undo init congestion window on false SYNACK timeout 2019-05-01 11:47:54 -04:00
tcp_nv.c
tcp_offload.c net: use indirect call wrappers at GRO transport layer 2018-12-15 13:23:02 -08:00
tcp_output.c tcp: better SYNACK sent timestamp 2019-05-01 11:47:54 -04:00
tcp_rate.c
tcp_recovery.c
tcp_scalable.c
tcp_timer.c tcp: Refactor pingpong code 2019-01-27 13:29:43 -08:00
tcp_ulp.c
tcp_vegas.c
tcp_vegas.h
tcp_veno.c
tcp_westwood.c
tcp_yeah.c
tcp.c tcp: properly reset skb->truesize for tx recycling 2019-04-19 16:42:33 -07:00
tunnel4.c net: Convert protocol error handlers from void to int 2018-11-08 17:13:08 -08:00
udp_diag.c
udp_impl.h udp: add missing rehash callback to udplite 2019-01-17 15:01:08 -08:00
udp_offload.c udp: use indirect call wrappers for GRO socket lookup 2018-12-15 13:23:02 -08:00
udp_tunnel.c net/ipv4/udp_tunnel: prefer SO_BINDTOIFINDEX over SO_BINDTODEVICE 2019-01-17 14:55:52 -08:00
udp.c datagram: remove rendundant 'peeked' argument 2019-04-08 09:51:54 -07:00
udplite.c udp: add missing rehash callback to udplite 2019-01-17 15:01:08 -08:00
xfrm4_input.c
xfrm4_output.c xfrm: store xfrm_mode directly, not its address 2019-04-08 09:15:28 +02:00
xfrm4_policy.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2019-04-30 09:26:13 -04:00
xfrm4_protocol.c xfrm: remove unneeded export_symbols 2019-04-23 07:42:20 +02:00
xfrm4_state.c
xfrm4_tunnel.c