linux/net/ipv4
Florian Westphal ce6dd23329 dctcp: avoid bogus doubling of cwnd after loss
If a congestion control module doesn't provide .undo_cwnd function,
tcp_undo_cwnd_reduction() will set cwnd to

   tp->snd_cwnd = max(tp->snd_cwnd, tp->snd_ssthresh << 1);

... which makes sense for reno (it sets ssthresh to half the current cwnd),
but it makes no sense for dctcp, which sets ssthresh based on the current
congestion estimate.

This can cause severe growth of cwnd (eventually overflowing u32).

Fix this by saving last cwnd on loss and restore cwnd based on that,
similar to cubic and other algorithms.

Fixes: e3118e8359 ("net: tcp: add DCTCP congestion control algorithm")
Cc: Lawrence Brakmo <brakmo@fb.com>
Cc: Andrew Shewmaker <agshew@gmail.com>
Cc: Glenn Judd <glenn.judd@morganstanley.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-31 15:16:28 -04:00
..
netfilter Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2016-09-25 23:34:19 +02:00
af_inet.c net: add recursion limit to GRO 2016-10-20 14:32:22 -04:00
ah4.c
arp.c net: rename NET_{ADD|INC}_STATS_BH() 2016-04-27 22:48:24 -04:00
cipso_ipv4.c Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/selinux into next 2016-07-07 10:15:34 +10:00
datagram.c
devinet.c netconf: add a notif when settings are created 2016-09-01 15:18:08 -07:00
esp4.c esp: Fix ESN generation under UDP encapsulation 2016-06-23 11:52:00 -04:00
fib_frontend.c switchdev: remove FIB offload infrastructure 2016-09-28 04:48:00 -04:00
fib_lookup.h
fib_rules.c switchdev: remove FIB offload infrastructure 2016-09-28 04:48:00 -04:00
fib_semantics.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-09-12 15:52:44 -07:00
fib_trie.c switchdev: remove FIB offload infrastructure 2016-09-28 04:48:00 -04:00
fou.c net: add recursion limit to GRO 2016-10-20 14:32:22 -04:00
gre_demux.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-06-30 05:03:36 -04:00
gre_offload.c net: add recursion limit to GRO 2016-10-20 14:32:22 -04:00
icmp.c net: icmp: rename ICMPMSGIN_INC_STATS_BH() 2016-04-27 22:48:23 -04:00
igmp.c net/multicast: should not send source list records when have filter mode change 2016-08-08 16:04:39 -07:00
inet_connection_sock.c timers, net/ipv4/inet: Initialize connection request timers as pinned 2016-07-07 10:35:06 +02:00
inet_diag.c net: inet: diag: expose the socket mark to privileged processes. 2016-09-08 16:13:09 -07:00
inet_fragment.c net: disable fragment reassembly if high_thresh is zero 2016-06-05 22:56:42 -04:00
inet_hashtables.c net: Require exact match for TCP socket lookups if dif is l3mdev 2016-10-17 10:17:05 -04:00
inet_timewait_sock.c timers, net/ipv4/inet: Initialize connection request timers as pinned 2016-07-07 10:35:06 +02:00
inetpeer.c
ip_forward.c net/ipv4: Introduce IPSKB_FRAG_SEGS bit to inet_skb_parm.flags 2016-07-19 16:40:22 -07:00
ip_fragment.c net: rename IP_INC_STATS_BH() 2016-04-27 22:48:23 -04:00
ip_gre.c net/ip_tunnels: Introduce tunnel_id_to_key32() and key32_to_tunnel_id() 2016-09-10 20:53:55 -07:00
ip_input.c net: VRF: Pass original iif to ip_route_input() 2016-09-16 04:24:07 -04:00
ip_options.c net: ipv4: Convert IP network timestamps to be y2038 safe 2016-03-01 17:18:44 -05:00
ip_output.c ipv4: Remove unused but set variable 2016-10-18 10:30:28 -04:00
ip_sockglue.c udp: fix IP_CHECKSUM handling 2016-10-26 17:33:22 -04:00
ip_tunnel_core.c ip_tunnel: do not clear l4 hashes 2016-09-09 19:33:11 -07:00
ip_tunnel.c ip_tunnel: add collect_md mode to IPIP tunnel 2016-09-17 10:13:07 -04:00
ip_vti.c vti: use right inner_mode for inbound inter address family policy checks 2016-09-09 09:02:08 +02:00
ipcomp.c
ipconfig.c net: ipconfig: Fix NULL pointer dereference on RARP/BOOTP/DHCP timeout 2016-08-22 21:04:41 -07:00
ipip.c ip_tunnel: add collect_md mode to IPIP tunnel 2016-09-17 10:13:07 -04:00
ipmr.c ipmr, ip6mr: fix scheduling while atomic and a deadlock with ipmr_get_route 2016-09-25 23:41:39 -04:00
Kconfig tcp_bbr: add BBR congestion control 2016-09-21 00:23:01 -04:00
Makefile tcp_bbr: add BBR congestion control 2016-09-21 00:23:01 -04:00
netfilter.c
ping.c udp: must lock the socket in udp_disconnect() 2016-10-20 14:45:52 -04:00
proc.c net: Suppress the "Comparison to NULL could be written" warnings 2016-09-30 01:50:45 -04:00
protocol.c
raw.c udp: must lock the socket in udp_disconnect() 2016-10-20 14:45:52 -04:00
route.c net: ipv4: Do not drop to make_route if oif is l3mdev 2016-10-13 12:05:26 -04:00
syncookies.c net: rename NET_{ADD|INC}_STATS_BH() 2016-04-27 22:48:24 -04:00
sysctl_net_ipv4.c ipv4: use the right lock for ping_group_range 2016-10-22 16:23:12 -04:00
tcp_bbr.c tcp_bbr: add BBR congestion control 2016-09-21 00:23:01 -04:00
tcp_bic.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_cdg.c tcp: cdg: rename struct minmax in tcp_cdg.c to avoid a naming conflict 2016-09-21 00:22:59 -04:00
tcp_cong.c tcp: new CC hook to set sending rate with rate_sample in any CA state 2016-09-21 00:23:01 -04:00
tcp_cubic.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_dctcp.c dctcp: avoid bogus doubling of cwnd after loss 2016-10-31 15:16:28 -04:00
tcp_diag.c net: diag: Fix refcnt leak in error path destroying socket 2016-08-23 23:11:36 -07:00
tcp_fastopen.c tcp: fastopen: avoid negative sk_forward_alloc 2016-09-08 16:08:10 -07:00
tcp_highspeed.c
tcp_htcp.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_hybla.c
tcp_illinois.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_input.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-10-02 22:20:41 -04:00
tcp_ipv4.c tcp: do not export sysctl_tcp_low_latency 2016-10-19 11:12:41 -04:00
tcp_lp.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_metrics.c tcp: make nla_policy const 2016-09-01 14:09:01 -07:00
tcp_minisocks.c tcp: track application-limited rate samples 2016-09-21 00:23:00 -04:00
tcp_nv.c tcp: add NV congestion control 2016-06-10 23:07:49 -07:00
tcp_offload.c gso: Support partial splitting at the frag_list pointer 2016-09-19 20:59:34 -04:00
tcp_output.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-10-02 22:20:41 -04:00
tcp_probe.c net: ipv4: tcp_probe: Replace timespec with timespec64 2016-03-01 17:18:44 -05:00
tcp_rate.c tcp: export data delivery rate 2016-09-21 00:23:00 -04:00
tcp_recovery.c tcp: do not assume TCP code is non preemptible 2016-05-02 17:02:25 -04:00
tcp_scalable.c
tcp_timer.c tcp: Change txhash on every SYN and RTO retransmit 2016-09-28 07:52:34 -04:00
tcp_vegas.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_vegas.h tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_veno.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_westwood.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_yeah.c tcp: cwnd does not increase in TCP YeAH 2016-09-08 17:16:12 -07:00
tcp.c Merge branch 'akpm' (patches from Andrew) 2016-10-07 21:38:00 -07:00
tunnel4.c tunnels: correct conditional build of MPLS and IPv6 2016-07-11 13:27:06 -07:00
udp_diag.c net: inet: diag: expose the socket mark to privileged processes. 2016-09-08 16:13:09 -07:00
udp_impl.h
udp_offload.c net: add recursion limit to GRO 2016-10-20 14:32:22 -04:00
udp_tunnel.c net: Remove deprecated tunnel specific UDP offload functions 2016-06-17 20:23:32 -07:00
udp.c udp: fix IP_CHECKSUM handling 2016-10-26 17:33:22 -04:00
udplite.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-08-30 00:54:02 -04:00
xfrm4_input.c
xfrm4_mode_beet.c
xfrm4_mode_transport.c
xfrm4_mode_tunnel.c
xfrm4_output.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-10-24 06:54:12 -07:00
xfrm4_policy.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-09-12 15:52:44 -07:00
xfrm4_protocol.c
xfrm4_state.c
xfrm4_tunnel.c