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linux/net/ipv4
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Yuchung Cheng fd2123a3d7 tcp: avoid resetting ACK timer upon receiving packet with ECN CWR flag 
Previously commit 9aee400061 ("tcp: ack immediately when a cwr
packet arrives") calls tcp_enter_quickack_mode to force sending
two immediate ACKs upon receiving a packet w/ CWR flag. The side
effect is it'll also reset the delayed ACK timer and interactive
session tracking. This patch removes that side effect by using the
new ACK_NOW flag to force an immmediate ACK.

Packetdrill to demonstrate:

    0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
   +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
   +0 setsockopt(3, SOL_TCP, TCP_CONGESTION, "dctcp", 5) = 0
   +0 bind(3, ..., ...) = 0
   +0 listen(3, 1) = 0

   +0 < [ect0] SEW 0:0(0) win 32792 <mss 1000,sackOK,nop,nop,nop,wscale 7>
   +0 > SE. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8>
  +.1 < [ect0] . 1:1(0) ack 1 win 257
   +0 accept(3, ..., ...) = 4

   +0 < [ect0] . 1:1001(1000) ack 1 win 257
   +0 > [ect01] . 1:1(0) ack 1001

   +0 write(4, ..., 1) = 1
   +0 > [ect01] P. 1:2(1) ack 1001

   +0 < [ect0] . 1001:2001(1000) ack 2 win 257
   +0 write(4, ..., 1) = 1
   +0 > [ect01] P. 2:3(1) ack 2001

   +0 < [ect0] . 2001:3001(1000) ack 3 win 257
   +0 < [ect0] . 3001:4001(1000) ack 3 win 257
   // Ack delayed ...

   +.01 < [ce] P. 4001:4501(500) ack 3 win 257
   +0 > [ect01] . 3:3(0) ack 4001
   +0 > [ect01] E. 3:3(0) ack 4501

+.001 read(4, ..., 4500) = 4500
   +0 write(4, ..., 1) = 1
   +0 > [ect01] PE. 3:4(1) ack 4501 win 100

 +.01 < [ect0] W. 4501:5501(1000) ack 4 win 257
   // No delayed ACK on CWR flag
   +0 > [ect01] . 4:4(0) ack 5501

 +.31 < [ect0] . 5501:6501(1000) ack 4 win 257
   +0 > [ect01] . 4:4(0) ack 6501

Fixes: 9aee400061 ("tcp: ack immediately when a cwr packet arrives")
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-11 11:31:35 -07:00
..
bpfilter bpfilter: remove trailing newline 2018-07-24 14:10:42 -07:00
netfilter Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next 2018-07-20 22:28:28 -07:00
af_inet.c net: ipv4: Control SKB reprioritization after forwarding 2018-08-01 09:52:30 -07:00
ah4.c
arp.c proc: introduce proc_create_net{,_data} 2018-05-16 07:24:30 +02:00
cipso_ipv4.c
datagram.c
devinet.c route: add support for directed broadcast forwarding 2018-07-29 12:37:06 -07:00
esp4_offload.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2018-07-27 09:33:37 -07:00
esp4.c esp4: remove redundant initialization of pointer esph 2018-02-13 13:59:03 +01:00
fib_frontend.c ipv4: remove BUG_ON() from fib_compute_spec_dst 2018-07-28 19:06:12 -07:00
fib_lookup.h
fib_notifier.c
fib_rules.c net: fib_rules: add extack support 2018-04-23 10:21:24 -04:00
fib_semantics.c net: metrics: add proper netlink validation 2018-06-05 12:29:43 -04:00
fib_trie.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-06-06 18:39:49 -07:00
fou.c Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/net 2018-07-03 10:29:26 +09:00
gre_demux.c
gre_offload.c Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/net 2018-07-03 10:29:26 +09:00
icmp.c ipv4: ipcm_cookie initializers 2018-07-07 10:58:49 +09:00
igmp.c Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/net 2018-08-02 10:55:32 -07:00
inet_connection_sock.c net: ipv4: remove define INET_CSK_DEBUG and unnecessary EXPORT_SYMBOL 2018-05-10 17:43:55 -04:00
inet_diag.c sock_diag: request _diag module only when the family or proto has been registered 2018-03-12 11:03:42 -04:00
inet_fragment.c ip: use rb trees for IP frag queue. 2018-08-05 17:16:46 -07:00
inet_hashtables.c net/tcp: Fix socket lookups with SO_BINDTODEVICE 2018-06-20 08:03:06 +09:00
inet_timewait_sock.c soreuseport: initialise timewait reuseport field 2018-04-07 22:32:32 -04:00
inetpeer.c inetpeer: fix uninit-value in inet_getpeer 2018-04-09 10:57:35 -04:00
ip_forward.c net: ipv4: Control SKB reprioritization after forwarding 2018-08-01 09:52:30 -07:00
ip_fragment.c ipv4: frags: precedence bug in ip_expire() 2018-08-06 13:15:12 -07:00
ip_gre.c ip_gre: remove redundant variables t_hlen 2018-08-01 09:58:15 -07:00
ip_input.c net: ipv4: fix listify ip_rcv_finish in case of forwarding 2018-07-12 16:40:19 -07:00
ip_options.c
ip_output.c Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/net 2018-07-24 19:21:58 -07:00
ip_sockglue.c ip: in cmsg IP(V6)_ORIGDSTADDR call pskb_may_pull 2018-07-24 16:35:58 -07:00
ip_tunnel_core.c net/ipv4: Update ip_tunnel_metadata_cnt static key to modern api 2018-05-10 15:13:33 -04:00
ip_tunnel.c ip_tunnel: Fix name string concatenate in __ip_tunnel_create() 2018-06-07 16:27:16 -04:00
ip_vti.c net: Drop pernet_operations::async 2018-03-27 13:18:09 -04:00
ipcomp.c
ipconfig.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-06-06 18:39:49 -07:00
ipip.c net: Drop pernet_operations::async 2018-03-27 13:18:09 -04:00
ipmr_base.c rhashtable: split rhashtable.h 2018-06-22 13:43:27 +09:00
ipmr.c net: ipmr: add support for passing full packet on wrong vif 2018-07-13 14:21:16 -07:00
Kconfig net: remove blank lines at end of file 2018-07-24 14:10:43 -07:00
Makefile net: remove blank lines at end of file 2018-07-24 14:10:43 -07:00
metrics.c net: metrics: add proper netlink validation 2018-06-05 12:29:43 -04:00
netfilter.c netfilter: utils: move nf_ip_checksum* from ipv4 to utils 2018-07-16 17:51:48 +02:00
netlink.c ipv4: support sport, dport and ip_proto in RTM_GETROUTE 2018-05-23 15:14:12 -04:00
ping.c net: add helpers checking if socket can be bound to nonlocal address 2018-08-01 09:50:04 -07:00
proc.c ip: discard IPv4 datagrams with overlapping segments. 2018-08-05 17:16:46 -07:00
protocol.c
raw_diag.c
raw.c ip: remove tx_flags from ipcm_cookie and use same logic for v4 and v6 2018-07-07 10:58:49 +09:00
route.c route: add support for directed broadcast forwarding 2018-07-29 12:37:06 -07:00
syncookies.c net/ipv4: disable SMC TCP option with SYN Cookies 2018-03-25 20:53:54 -04:00
sysctl_net_ipv4.c net: ipv4: Notify about changes to ip_forward_update_priority 2018-08-01 09:52:30 -07:00
tcp_bbr.c Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/net 2018-08-02 10:55:32 -07:00
tcp_bic.c
tcp_cdg.c
tcp_cong.c
tcp_cubic.c
tcp_dctcp.c tcp: avoid resetting ACK timer in DCTCP 2018-08-11 11:31:35 -07:00
tcp_diag.c net: sock: replace sk_state_load with inet_sk_state_load and remove sk_state_store 2017-12-20 14:00:25 -05:00
tcp_fastopen.c tcp: pause Fast Open globally after third consecutive timeout 2017-12-13 15:51:12 -05:00
tcp_highspeed.c
tcp_htcp.c
tcp_hybla.c
tcp_illinois.c net/tcp/illinois: replace broken algorithm reference link 2018-02-28 12:03:47 -05:00
tcp_input.c tcp: avoid resetting ACK timer upon receiving packet with ECN CWR flag 2018-08-11 11:31:35 -07:00
tcp_ipv4.c Merge ra.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux 2018-07-20 21:17:12 -07:00
tcp_lp.c
tcp_metrics.c net: Drop pernet_operations::async 2018-03-27 13:18:09 -04:00
tcp_minisocks.c tcp: use monotonic timestamps for PAWS 2018-07-12 14:50:40 -07:00
tcp_nv.c tcp_nv: fix potential integer overflow in tcpnv_acked 2018-01-31 10:26:30 -05:00
tcp_offload.c tcp: Don't coalesce decrypted and encrypted SKBs 2018-07-16 00:12:09 -07:00
tcp_output.c tcp: remove set but not used variable 'skb_size' 2018-08-01 09:57:09 -07:00
tcp_rate.c tcp: expose both send and receive intervals for rate sample 2018-07-11 23:01:56 -07:00
tcp_recovery.c tcp: add stat of data packet reordering events 2018-08-01 09:56:10 -07:00
tcp_scalable.c
tcp_timer.c tcp: make function tcp_retransmit_stamp() static 2018-07-25 16:35:45 -07:00
tcp_ulp.c net: add a UID to use for ULP socket assignment 2018-02-06 11:39:31 +01:00
tcp_vegas.c
tcp_vegas.h
tcp_veno.c
tcp_westwood.c
tcp_yeah.c
tcp.c tcp: remove unneeded variable 'err' 2018-08-03 16:52:07 -07:00
tunnel4.c inet: whitespace cleanup 2018-02-28 11:43:28 -05:00
udp_diag.c udp: fix rx queue len reported by diag and proc interface 2018-06-08 19:55:15 -04:00
udp_impl.h
udp_offload.c Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/net 2018-07-03 10:29:26 +09:00
udp_tunnel.c
udp.c ip: remove tx_flags from ipcm_cookie and use same logic for v4 and v6 2018-07-07 10:58:49 +09:00
udplite.c proc: introduce proc_create_net{,_data} 2018-05-16 07:24:30 +02:00
xfrm4_input.c xfrm: Reinject transport-mode packets through tasklet 2017-12-19 08:23:21 +01:00
xfrm4_mode_beet.c
xfrm4_mode_transport.c
xfrm4_mode_tunnel.c xfrm: Verify MAC header exists before overwriting eth_hdr(skb)->h_proto 2018-03-07 10:54:29 +01:00
xfrm4_output.c net: xfrm: use skb_gso_validate_network_len() to check gso sizes 2018-03-04 17:49:17 -05:00
xfrm4_policy.c net: Drop pernet_operations::async 2018-03-27 13:18:09 -04:00
xfrm4_protocol.c
xfrm4_state.c
xfrm4_tunnel.c