linux/net
Eric Dumazet 662051215c tcp: grow window for OOO packets only for SACK flows
Back in 2013, we made a change that broke fast retransmit
for non SACK flows.

Indeed, for these flows, a sender needs to receive three duplicate
ACK before starting fast retransmit. Sending ACK with different
receive window do not count.

Even if enabling SACK is strongly recommended these days,
there still are some cases where it has to be disabled.

Not increasing the window seems better than having to
rely on RTO.

After the fix, following packetdrill test gives :

// Initialize connection
    0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
   +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
   +0 bind(3, ..., ...) = 0
   +0 listen(3, 1) = 0

   +0 < S 0:0(0) win 32792 <mss 1000,nop,wscale 7>
   +0 > S. 0:0(0) ack 1 <mss 1460,nop,wscale 8>
   +0 < . 1:1(0) ack 1 win 514

   +0 accept(3, ..., ...) = 4

   +0 < . 1:1001(1000) ack 1 win 514
// Quick ack
   +0 > . 1:1(0) ack 1001 win 264

   +0 < . 2001:3001(1000) ack 1 win 514
// DUPACK : Normally we should not change the window
   +0 > . 1:1(0) ack 1001 win 264

   +0 < . 3001:4001(1000) ack 1 win 514
// DUPACK : Normally we should not change the window
   +0 > . 1:1(0) ack 1001 win 264

   +0 < . 4001:5001(1000) ack 1 win 514
// DUPACK : Normally we should not change the window
    +0 > . 1:1(0) ack 1001 win 264

   +0 < . 1001:2001(1000) ack 1 win 514
// Hole is repaired.
   +0 > . 1:1(0) ack 5001 win 272

Fixes: 4e4f1fc226 ("tcp: properly increase rcv_ssthresh for ofo packets")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Venkat Venkatsubra <venkat.x.venkatsubra@oracle.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-16 13:38:19 -07:00
..
6lowpan treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
9p 9p/xen: increase XEN_9PFS_RING_ORDER 2020-06-02 08:00:39 +02:00
802 net: 802: psnap.c: Use built-in RCU list checking 2020-02-24 13:02:53 -08:00
8021q Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
appletalk ipv4,appletalk: move SIOCADDRT and SIOCDELRT handling into ->compat_ioctl 2020-05-18 17:35:02 -07:00
atm Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
ax25 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-05-24 13:47:27 -07:00
batman-adv net: change addr_list_lock back to static key 2020-06-09 12:59:45 -07:00
bluetooth Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-06-03 16:27:18 -07:00
bpf bpf: Fix too large copy from user in bpf_test_init 2020-05-19 17:56:34 +02:00
bpfilter bpfilter: document build requirements for bpfilter_umh 2020-05-26 00:03:16 +09:00
bridge Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
caif treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
can treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
ceph The highlights are: 2020-06-08 12:49:18 -07:00
core Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
dcb treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
dccp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
decnet treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
dns_resolver docs: networking: convert dns_resolver.txt to ReST 2020-04-28 14:39:46 -07:00
dsa Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
ethernet net: move devres helpers into a separate source file 2020-05-23 16:56:17 -07:00
ethtool ethtool: linkinfo: remove an unnecessary NULL check 2020-06-05 13:10:02 -07:00
hsr treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
ieee802154 treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
ife
ipv4 tcp: grow window for OOO packets only for SACK flows 2020-06-16 13:38:19 -07:00
ipv6 mld: fix memory leak in ipv6_mc_destroy_dev() 2020-06-15 13:29:39 -07:00
iucv net/af_iucv: clean up function prototypes 2020-05-19 12:50:14 -07:00
kcm treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
key
l2tp treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
l3mdev treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
lapb treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
llc af_llc: fix if-statement empty body warning 2020-02-26 20:38:13 -08:00
mac80211 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
mac802154 treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
mpls treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
mptcp mptcp: fix memory leak in mptcp_subflow_create_socket() 2020-06-15 18:08:50 -07:00
ncsi treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
netfilter netfilter: flowtable: Make nf_flow_table_offload_add/del_cb inline 2020-06-15 18:06:52 -07:00
netlabel treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
netlink Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
netrom net: change addr_list_lock back to static key 2020-06-09 12:59:45 -07:00
nfc treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
nsh treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
openvswitch treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
packet treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
phonet sysctl: pass kernel pointers to ->proc_handler 2020-04-27 02:07:40 -04:00
psample net: psample: fix build error when CONFIG_INET is not enabled 2020-05-23 16:36:05 -07:00
qrtr treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
rds net/rds: NULL pointer de-reference in rds_ib_add_one() 2020-06-15 12:58:59 -07:00
rfkill rfkill: Fix incorrect check to avoid NULL pointer dereference 2019-12-16 10:15:49 +01:00
rose net: change addr_list_lock back to static key 2020-06-09 12:59:45 -07:00
rxrpc rxrpc: Fix race between incoming ACK parser and retransmitter 2020-06-11 18:18:22 -07:00
sched net/sched: act_ct: Make tcf_ct_flow_table_restore_skb inline 2020-06-15 18:06:52 -07:00
sctp treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
smc treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
strparser
sunrpc NFS Client Updates for Linux 5.8 2020-06-11 12:22:41 -07:00
switchdev treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
tipc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
tls treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
unix treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
vmw_vsock vsock/vmci: make vmci_vsock_transport_cb() static 2020-06-05 13:18:26 -07:00
wimax
wireless Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
x25 treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
xdp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
xfrm treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
compat.c switch cmsghdr_from_user_compat_to_kern() to copy_from_user() 2020-06-01 12:05:45 -07:00
devres.c net: devres: provide devm_register_netdev() 2020-05-23 16:56:17 -07:00
Kconfig treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
Makefile net: move devres helpers into a separate source file 2020-05-23 16:56:17 -07:00
socket.c net: remove kernel_setsockopt 2020-05-29 13:10:39 -07:00
sysctl_net.c