Stewart Smith d11b0df7dd tcp: Reduce chance of collisions in inet6_hashfn(). ... For both IPv4 and IPv6 incoming TCP connections are tracked in a hash table with a hash over the source & destination addresses and ports. However, the IPv6 hash is insufficient and can lead to a high rate of collisions. The IPv6 hash used an XOR to fit everything into the 96 bits for the fast jenkins hash, meaning it is possible for an external entity to ensure the hash collides, thus falling back to a linear search in the bucket, which is slow. We take the approach of hash the full length of IPv6 address in __ipv6_addr_jhash() so that all users can benefit from a more secure version. While this may look like it adds overhead, the reality of modern CPUs means that this is unmeasurable in real world scenarios. In simulating with llvm-mca, the increase in cycles for the hashing code was ~16 cycles on Skylake (from a base of ~155), and an extra ~9 on Nehalem (base of ~173). In commit dd6d2910c5 ("netfilter: conntrack: switch to siphash") netfilter switched from a jenkins hash to a siphash, but even the faster hsiphash is a more significant overhead (~20-30%) in some preliminary testing. So, in this patch, we keep to the more conservative approach to ensure we don't add much overhead per SYN. In testing, this results in a consistently even spread across the connection buckets. In both testing and real-world scenarios, we have not found any measurable performance impact. Fixes: 08dcdbf6a7 ("ipv6: use a stronger hash for tcp") Signed-off-by: Stewart Smith <trawets@amazon.com> Signed-off-by: Samuel Mendoza-Jonas <samjonas@amazon.com> Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20230721222410.17914-1-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>		2023-07-24 16:52:37 -07:00
..
9p	9p: Add additional debug flags and open modes	2023-03-27 02:33:48 +00:00
bluetooth	Bluetooth: coredump: fix building with coredump disabled	2023-07-20 11:25:24 -07:00
caif	…
iucv	…
mana	Linux 6.4	2023-06-27 14:06:29 -03:00
netfilter	netfilter: conntrack: don't fold port numbers into addresses before hashing	2023-07-05 14:42:16 +02:00
netns	tcp: enforce receive buffer memory limits by allowing the tcp window to shrink	2023-06-17 09:53:53 +01:00
nfc	…
phonet	net: ioctl: Use kernel memory on protocol ioctl callbacks	2023-06-15 22:33:26 -07:00
sctp	sctp: delete the nested flexible array peer_init	2023-04-21 08:19:30 +01:00
tc_act	net/sched: act_connmark: transition to percpu stats and rcu	2023-02-16 10:39:28 +01:00
6lowpan.h	…
Space.h	…
act_api.h	net/sched: Rename user cookie and act cookie	2023-02-20 16:46:10 -08:00
addrconf.h	ipv6: constify inet6_mc_check()	2023-03-17 08:56:37 +00:00
af_ieee802154.h	…
af_rxrpc.h	rxrpc: Fix timeout of a call that hasn't yet been granted a channel	2023-05-01 07:43:19 +01:00
af_unix.h	af_unix: preserve const qualifier in unix_sk()	2023-03-18 12:23:33 +00:00
af_vsock.h	vsock: support sockmap	2023-03-29 08:19:38 +01:00
ah.h	…
amt.h	…
arp.h	neighbour: switch to standard rcu, instead of rcu_bh	2023-03-21 21:32:18 -07:00
atmclip.h	…
ax25.h	x25: preserve const qualifier in [a]x25_sk()	2023-03-18 12:23:34 +00:00
ax88796.h	…
bareudp.h	…
bond_3ad.h	…
bond_alb.h	…
bond_options.h	…
bonding.h	net: bonding: remove kernel-doc comment marker	2023-07-14 20:39:29 -07:00
bpf_sk_storage.h	…
busy_poll.h	…
calipso.h	…
cfg80211-wext.h	…
cfg80211.h	wifi: cfg80211: Retrieve PSD information from RNR AP information	2023-06-21 14:01:29 +02:00
cfg802154.h	net: cfg802154: fix kernel-doc notation warnings	2023-07-14 20:39:29 -07:00
checksum.h	net: checksum: drop the linux/uaccess.h include	2023-01-27 11:19:46 +00:00
cipso_ipv4.h	…
cls_cgroup.h	…
codel.h	codel: fix kernel-doc notation warnings	2023-07-14 20:39:29 -07:00
codel_impl.h	…
codel_qdisc.h	…
compat.h	…
datalink.h	…
dcbevent.h	…
dcbnl.h	net: dcb: add helper functions to retrieve PCP and DSCP rewrite maps	2023-01-20 09:33:22 +00:00
devlink.h	devlink: fix kernel-doc notation warnings	2023-07-14 20:39:29 -07:00
dropreason-core.h	net: extend drop reasons for multiple subsystems	2023-04-20 20:20:49 -07:00
dropreason.h	mac80211: use the new drop reasons infrastructure	2023-04-20 20:20:49 -07:00
dsa.h	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2023-06-27 09:45:22 -07:00
dsa_stubs.h	net: dsa: replace NETDEV_PRE_CHANGE_HWTSTAMP notifier with a stub	2023-04-09 15:35:49 +01:00
dsfield.h	…
dst.h	net: dst: Switch to rcuref_t reference counting	2023-03-28 18:52:28 -07:00
dst_cache.h	…
dst_metadata.h	xfrm: interface: Add unstable helpers for setting/getting XFRM metadata from TC-BPF	2022-12-05 21:58:27 -08:00
dst_ops.h	ipv6: remove max_size check inline with ipv4	2023-01-13 20:59:14 -08:00
erspan.h	…
esp.h	…
espintcp.h	…
ethoc.h	…
failover.h	…
fib_notifier.h	…
fib_rules.h	…
firewire.h	…
flow.h	ipv4: Drop tos parameter from flowi4_update_output()	2023-06-02 10:52:38 +01:00
flow_dissector.h	net: flow_dissector: add support for cfm packets	2023-06-12 17:01:45 -07:00
flow_offload.h	net/sched: cls_api: Support hardware miss to tc action	2023-02-20 16:46:10 -08:00
fou.h	bpf,fou: Add bpf_skb_{set,get}_fou_encap kfuncs	2023-04-12 16:40:39 -07:00
fq.h	…
fq_impl.h	wifi: mac80211: add support for restricting netdev features per vif	2022-12-01 15:09:10 +01:00
garp.h	…
gen_stats.h	…
genetlink.h	…
geneve.h	…
gre.h	…
gro.h	net: move gso declarations and functions to their own files	2023-06-10 00:11:41 -07:00
gro_cells.h	…
gso.h	net: move gso declarations and functions to their own files	2023-06-10 00:11:41 -07:00
gtp.h	…
gue.h	…
handshake.h	net/handshake: Enable the SNI extension to work properly	2023-05-24 22:05:24 -07:00
hwbm.h	…
icmp.h	…
ieee80211_radiotap.h	wifi: iwlwifi: mvm: support U-SIG EHT validate checks	2023-06-14 12:32:19 +02:00
ieee802154_netdev.h	mac802154: Handle received BEACON_REQ	2023-03-23 21:51:30 +01:00
if_inet6.h	…
ife.h	…
ila.h	…
inet6_connection_sock.h	…
inet6_hashtables.h	…
inet_common.h	sock: Remove ->sendpage*() in favour of sendmsg(MSG_SPLICE_PAGES)	2023-06-24 15:50:13 -07:00
inet_connection_sock.h	…
inet_dscp.h	…
inet_ecn.h	…
inet_frag.h	inet: frags: eliminate kernel-doc warning	2023-07-14 20:39:29 -07:00
inet_hashtables.h	tcp: Add TIME_WAIT sockets in bhash2.	2022-12-30 07:25:52 +00:00
inet_sock.h	inet: preserve const qualifier in inet_sk()	2023-03-17 08:56:37 +00:00
inet_timewait_sock.h	tcp: Add TIME_WAIT sockets in bhash2.	2022-12-30 07:25:52 +00:00
inetpeer.h	…
ioam6.h	…
ip.h	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2023-05-25 19:57:39 -07:00
ip6_checksum.h	…
ip6_fib.h	ipv6: Remove in6addr_any alternatives.	2023-03-29 08:22:52 +01:00
ip6_route.h	net: dst: Prevent false sharing vs. dst_entry:: __refcnt	2023-03-28 18:52:22 -07:00
ip6_tunnel.h	…
ip_fib.h	…
ip_tunnels.h	bpf-next-for-netdev	2023-04-13 16:43:38 -07:00
ip_vs.h	ipvs: Correct spelling in comments	2023-04-22 01:39:41 +02:00
ipcomp.h	…
ipconfig.h	…
ipv6.h	tcp: Reduce chance of collisions in inet6_hashfn().	2023-07-24 16:52:37 -07:00
ipv6_frag.h	…
ipv6_stubs.h	…
iw_handler.h	…
kcm.h	kcm: Send multiple frags in one sendmsg()	2023-06-12 21:13:23 -07:00
l3mdev.h	…
lag.h	…
lapb.h	…
lib80211.h	…
llc.h	…
llc_c_ac.h	…
llc_c_ev.h	…
llc_c_st.h	…
llc_conn.h	llc: Check netns in llc_estab_match() and llc_listener_match().	2023-07-20 10:46:28 +02:00
llc_if.h	…
llc_pdu.h	net: llc: fix kernel-doc notation warnings	2023-07-14 20:39:29 -07:00
llc_s_ac.h	…
llc_s_ev.h	…
llc_s_st.h	…
llc_sap.h	…
lwtunnel.h	…
mac80211.h	wifi: mac80211: fix documentation config reference	2023-06-21 09:16:57 +02:00
mac802154.h	…
macsec.h	macsec: Use helper macsec_netdev_priv for offload drivers	2023-05-10 11:32:09 +01:00
mctp.h	mctp: Reorder fields in 'struct mctp_route'	2023-06-20 20:06:16 -07:00
mctpdevice.h	…
mip6.h	…
mld.h	…
mpls.h	…
mpls_iptunnel.h	…
mptcp.h	mptcp: remove MPTCP 'ifdef' in TCP SYN cookies	2022-12-12 13:11:24 -08:00
mrp.h	…
ncsi.h	…
ndisc.h	neighbour: switch to standard rcu, instead of rcu_bh	2023-03-21 21:32:18 -07:00
neighbour.h	neighbour: fix unaligned access to pneigh_entry	2023-06-01 21:36:37 -07:00
net_debug.h	…
net_failover.h	…
net_namespace.h	…
net_ratelimit.h	…
net_trackers.h	…
netdev_queues.h	net: add macro netif_subqueue_completed_wake	2023-04-18 12:59:01 +02:00
netevent.h	…
netlabel.h	…
netlink.h	net: netlink: recommend policy range validation	2023-01-28 00:33:51 -08:00
netprio_cgroup.h	…
netrom.h	…
nexthop.h	ipv6: remove nexthop_fib6_nh_bh()	2023-05-11 18:07:05 -07:00
nl802154.h	ieee802154: Add support for user beaconing requests	2023-01-28 13:51:22 +01:00
nsh.h	net: NSH: fix kernel-doc notation warning	2023-07-14 20:39:29 -07:00
p8022.h	…
page_pool.h	page_pool: fix inconsistency for page_pool_ring_[un]lock()	2023-05-23 20:25:13 -07:00
pie.h	pie: fix kernel-doc notation warning	2023-07-14 20:39:30 -07:00
ping.h	net/ipv4: ping_group_range: allow GID from 2147483648 to 4294967294	2023-06-02 09:55:22 +01:00
pkt_cls.h	sch_htb: Allow HTB priority parameter in offload mode	2023-05-15 09:31:07 +01:00
pkt_sched.h	net/sched: make psched_mtu() RTNL-less safe	2023-07-12 15:59:33 -07:00
pptp.h	…
protocol.h	…
psample.h	…
psnap.h	…
raw.h	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2023-04-06 12:01:20 -07:00
rawv6.h	ipv6: raw: constify raw_v6_match() socket argument	2023-03-17 08:56:37 +00:00
red.h	…
regulatory.h	wifi: cfg80211: fix regulatory disconnect with OCB/NAN	2023-06-19 12:05:29 +02:00
request_sock.h	…
rose.h	…
route.h	ipv4: Drop tos parameter from flowi4_update_output()	2023-06-02 10:52:38 +01:00
rpl.h	ipv6: rpl: Remove pskb(_may)?_pull() in ipv6_rpl_srh_rcv().	2023-06-19 11:32:58 -07:00
rsi_91x.h	rsi: remove kernel-doc comment marker	2023-07-14 20:39:30 -07:00
rtnetlink.h	…
rtnh.h	…
sch_generic.h	net: sched: Remove unused qdisc_l2t()	2023-06-17 00:17:42 -07:00
scm.h	net: scm: introduce and use scm_recv_unix helper	2023-06-27 10:50:22 -07:00
secure_seq.h	…
seg6.h	…
seg6_hmac.h	…
seg6_local.h	…
selftests.h	…
slhc_vj.h	…
smc.h	net/smc: Introduce explicit check for v2 support	2023-03-15 08:18:35 +00:00
snmp.h	…
sock.h	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2023-06-27 09:45:22 -07:00
sock_reuseport.h	…
stp.h	…
strparser.h	…
switchdev.h	…
tc_wrapper.h	net/sched: Retire rsvp classifier	2023-02-16 09:27:07 +01:00
tcp.h	tcp: annotate data-races around tp->notsent_lowat	2023-07-20 12:34:18 -07:00
tcp_states.h	…
timewait_sock.h	…
tipc.h	…
tls.h	net: tls: make the offload check helper take skb not socket	2023-06-15 09:01:05 +01:00
tls_toe.h	…
transp_v6.h	…
tso.h	net: tso: inline tso_count_descs()	2022-12-12 15:04:39 -08:00
tun_proto.h	…
udp.h	net: ioctl: Use kernel memory on protocol ioctl callbacks	2023-06-15 22:33:26 -07:00
udp_tunnel.h	…
udplite.h	…
vsock_addr.h	…
vxlan.h	vxlan: calculate correct header length for GPE	2023-07-24 09:37:32 +01:00
wext.h	…
x25.h	x25: preserve const qualifier in [a]x25_sk()	2023-03-18 12:23:34 +00:00
x25device.h	…
xdp.h	bpf-next-for-netdev	2023-04-13 16:43:38 -07:00
xdp_priv.h	…
xdp_sock.h	bpf, net: xskmap memory usage	2023-03-07 09:33:43 -08:00
xdp_sock_drv.h	xsk: Remove unused inline function xsk_buff_discard()	2023-06-19 14:06:22 +02:00
xfrm.h	xfrm: Treat already-verified secpath entries as optional	2023-05-21 09:21:37 +02:00
xsk_buff_pool.h	xsk: Use pool->dma_pages to check for DMA	2023-04-27 22:24:51 +02:00