Neal Cardwell 032ee42369 tcp: helpers to mitigate ACK loops by rate-limiting out-of-window dupacks ... Helpers for mitigating ACK loops by rate-limiting dupacks sent in response to incoming out-of-window packets. This patch includes: - rate-limiting logic - sysctl to control how often we allow dupacks to out-of-window packets - SNMP counter for cases where we rate-limited our dupack sending The rate-limiting logic in this patch decides to not send dupacks in response to out-of-window segments if (a) they are SYNs or pure ACKs and (b) the remote endpoint is sending them faster than the configured rate limit. We rate-limit our responses rather than blocking them entirely or resetting the connection, because legitimate connections can rely on dupacks in response to some out-of-window segments. For example, zero window probes are typically sent with a sequence number that is below the current window, and ZWPs thus expect to thus elicit a dupack in response. We allow dupacks in response to TCP segments with data, because these may be spurious retransmissions for which the remote endpoint wants to receive DSACKs. This is safe because segments with data can't realistically be part of ACK loops, which by their nature consist of each side sending pure/data-less ACKs to each other. The dupack interval is controlled by a new sysctl knob, tcp_invalid_ratelimit, given in milliseconds, in case an administrator needs to dial this upward in the face of a high-rate DoS attack. The name and units are chosen to be analogous to the existing analogous knob for ICMP, icmp_ratelimit. The default value for tcp_invalid_ratelimit is 500ms, which allows at most one such dupack per 500ms. This is chosen to be 2x faster than the 1-second minimum RTO interval allowed by RFC 6298 (section 2, rule 2.4). We allow the extra 2x factor because network delay variations can cause packets sent at 1 second intervals to be compressed and arrive much closer. Reported-by: Avery Fay <avery@mixpanel.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2015-02-08 01:03:12 -08:00
..
ABI	Revert "Documentation: Add entry for dell-laptop sysfs interface"	2015-01-23 11:10:12 -08:00
accounting	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
acpi	ACPI / GPIO: Document ACPI GPIO mappings API	2014-11-04 21:58:24 +01:00
aoe
arm	Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm	2014-12-12 15:26:48 -08:00
arm64	arm64: Emulate CP15 Barrier instructions	2014-11-20 16:34:48 +00:00
auxdisplay	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
backlight	backlight: lp855x_bl: support new LP8555 device	2013-11-13 12:09:14 +09:00
blackfin	Documentation: add makefiles for more targets	2014-09-26 11:02:56 +02:00
block	Merge branch 'for-3.19/core' of git://git.kernel.dk/linux-block	2014-12-13 14:14:23 -08:00
blockdev	zram: report maximum used memory	2014-10-09 22:26:02 -04:00
bus-devices
cdrom
cgroups	Merge branch 'akpm' (second patch-bomb from Andrew)	2014-12-13 13:00:36 -08:00
connector	w1: optional bundling of netlink kernel replies	2014-05-27 13:56:21 -07:00
console
cpu-freq	intel_pstate: Add support for HWP	2014-11-12 00:04:38 +01:00
cpuidle
cris
crypto	crypto: doc - userspace interface spec	2014-11-13 22:31:38 +08:00
development-process	Documentation: remove outdated references to the linux-next wiki	2014-10-28 09:06:11 -04:00
device-mapper	dm cache policy mq: simplify ability to promote sequential IO to the cache	2014-11-10 15:25:30 -05:00
devicetree	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2015-02-05 14:33:28 -08:00
dmaengine	Documentation: dmanegine: move dmatest.txt to dmaengine folder	2014-11-06 11:17:37 +05:30
DocBook	Last round of updates for net-next:	2015-02-04 14:57:45 -08:00
driver-model	PCI changes for the v3.18 merge window:	2014-10-09 15:03:49 -04:00
dvb	[media] get_dvb_firmware: Update firmware of ITEtech IT9135	2014-09-21 17:03:04 -03:00
early-userspace
EDID	drm: Add 800x600 (SVGA) screen resolution to the built-in EDIDs	2014-05-26 12:53:40 +10:00
extcon	extcon: fix switch class porting guide (Documentation)	2014-01-07 11:54:28 +09:00
fault-injection
fb	doc: spelling error changes	2014-05-05 15:32:05 +02:00
filesystems	These patches optionally add LZ4 compression support to Squashfs.	2014-12-14 14:42:53 -08:00
firmware_class	doc: fix minor typos in firmware_class README	2014-07-17 18:43:40 -07:00
fmc	FMC: make eeprom attribute writable	2014-02-28 15:12:08 -08:00
frv
gpio	This is the bulk of GPIO changes for the v3.19 series:	2014-12-14 14:05:05 -08:00
hid	HID: uhid: update documentation	2014-08-25 03:28:09 -05:00
hwmon	hwmon: (tmp401) Detect TMP435 on all addresses it supports	2014-12-08 06:48:37 -08:00
i2c	Documentation: i2c: Use PM ops instead of legacy suspend/resume	2014-12-04 19:09:03 +01:00
i2o
ia64	kvm: Documentation: remove ia64	2014-11-20 11:08:55 +01:00
ide	Documentation/: update 00-INDEX files	2014-02-10 16:01:40 -08:00
infiniband	IB/mad: add new ioctl to ABI to support new registration options	2014-08-10 20:36:00 -07:00
input	Docs changes for the 3.19 merge window	2014-12-12 14:42:48 -08:00
ioctl	cxl: Add documentation for userspace APIs	2014-10-08 20:16:19 +11:00
isdn
ja_JP	Documentation: Update stable address in Chinese and Japanese translations	2014-04-16 14:13:27 -07:00
kbuild	Documentation: kbuild: Improve grammar	2014-08-19 10:02:56 +02:00
kdump	kernel: add panic_on_warn	2014-12-10 17:41:10 -08:00
ko_KR	Documentation: HOWTO: Updates on subsystem trees, patchwork, -next (vs. -mm) in ko_KR	2014-01-08 15:32:51 -08:00
laptops	Documentation: update .gitignore files	2014-09-26 11:02:59 +02:00
leds	Documentation/: update 00-INDEX files	2014-02-10 16:01:40 -08:00
locking	Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-12-09 19:59:22 -08:00
m68k	Documentation/: update 00-INDEX files	2014-02-10 16:01:40 -08:00
memory-devices
metag
mic	Documentation: Build mic/mpssd only for x86_64	2014-12-05 11:18:36 -05:00
mips	Documentation: au1xxx-ide.c has moved	2014-08-26 09:35:53 +02:00
misc-devices	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
mmc
mn10300
mtd	MTD updates for 3.16:	2014-06-11 08:35:34 -07:00
namespaces
netlabel
networking	tcp: helpers to mitigate ACK loops by rate-limiting out-of-window dupacks	2015-02-08 01:03:12 -08:00
nfc
nios2	Documentation: Add documentation for Nios2 architecture	2014-12-08 12:56:06 +08:00
parisc
PCI	doc: replace "practise" with "practice" in Documentation	2014-06-19 15:28:56 +02:00
pcmcia	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
phy	phy: Add new Exynos USB 2.0 PHY driver	2014-03-08 12:39:44 +05:30
platform	Documentation: Add list of laptop models supported by the Compal driver	2014-06-10 19:11:06 -04:00
power	Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm	2014-12-12 15:26:48 -08:00
powerpc	cxl: Add documentation for userspace APIs	2014-10-08 20:16:19 +11:00
pps
prctl	Documentation: Restrict TSC test code to x86	2014-10-28 08:46:27 -04:00
pti
ptp	ptp: restore the makefile for building the test program.	2014-10-24 16:07:10 -04:00
rapidio	rapidio/tsi721_dma: rework scatter-gather list handling	2014-08-08 15:57:24 -07:00
RCU	Merge branches 'torture.2014.11.03a', 'cpu.2014.11.03a', 'doc.2014.11.13a', 'fixes.2014.11.13a', 'signal.2014.10.29a' and 'rt.2014.10.29a' into HEAD	2014-11-13 10:39:04 -08:00
s390	s390/docs: Remove sections that are not related to s390	2014-11-18 18:22:59 +01:00
scheduler	Documentation/scheduler/sched-deadline.txt: Add minimal main() appendix	2014-09-16 10:23:45 +02:00
scsi	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2014-12-12 10:08:06 -08:00
security	Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity into next	2014-11-19 21:36:07 +11:00
serial	serial: Fix locking for uart driver set_termios() method	2014-11-05 18:53:54 -08:00
sh
sound	ALSA: hda - Add "eapd" model string for AD1986A codec	2014-12-10 14:00:13 +01:00
spi	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/doc	2014-10-07 21:14:57 -04:00
sysctl	net-timestamp: no-payload only sysctl	2015-02-02 18:46:51 -08:00
target	Documentation/target: Update fabric_ops to latest code	2015-01-06 13:46:49 -08:00
thermal	Documentation: thermal: document of_cpufreq_cooling_register()	2015-01-06 14:39:17 -04:00
timers	Documentation: update .gitignore files	2014-09-26 11:02:59 +02:00
tpm
trace	Char/Misc driver patches for 3.19-rc1	2014-12-14 16:43:47 -08:00
usb	USB patches for 3.19-rc1	2014-12-14 14:57:16 -08:00
vDSO	vdso: don't require 64-bit math in standalone test	2014-10-25 10:53:44 -04:00
video4linux	[media] vivid.txt: document new controls	2014-12-16 23:21:37 -02:00
virtual	Second round of changes for KVM for arm/arm64 for v3.19; fixes reboot	2014-12-15 13:06:40 +01:00
vm	Merge branch 'akpm' (second patch-bomb from Andrew)	2014-12-13 13:00:36 -08:00
w1	w1: new w1_ds2406 driver	2014-06-19 17:45:14 -07:00
watchdog	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
wimax
x86	Merge branch 'x86-mpx-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-12-19 13:22:42 -08:00
xtensa	xtensa: remap io area defined in device tree	2014-01-15 00:25:14 +04:00
zh_CN	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2014-08-06 21:03:53 -07:00
00-INDEX	locking/Documentation: Move locking related docs into Documentation/locking/	2014-08-13 10:32:03 +02:00
applying-patches.txt	Documentation: change "&" to "and" in Documentation/applying-patches.txt	2014-09-26 11:10:11 +02:00
assoc_array.txt	KEYS: Fix multiple key add into associative array	2013-12-02 11:24:18 +00:00
atomic_ops.txt	documentation: Add atomic_long_t to atomic_ops.txt	2014-11-13 10:34:54 -08:00
bad_memory.txt
basic_profiling.txt
bcache.txt
binfmt_misc.txt	binfmt_misc: touch up documentation a bit	2014-10-14 02:18:16 +02:00
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt
cachetlb.txt
Changes	Update old iproute2 and Xen Remus links	2014-12-09 13:38:13 -05:00
circular-buffers.txt	documentation: Update circular buffer for load-acquire/store-release	2013-12-03 10:08:57 -08:00
clk.txt	clk: Change clk_ops->determine_rate to return a clk_hw as the best parent	2014-12-03 16:21:37 -08:00
coccinelle.txt
CodingStyle	CodingStyle: add some more error handling guidelines	2014-12-02 08:55:32 -05:00
cpu-hotplug.txt	Doc/cpu-hotplug: Specify race-free way to register CPU hotplug callbacks	2014-03-20 13:43:40 +01:00
cpu-load.txt
cputopology.txt
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt	firewire: revert to 4 GB RDMA, fix protocols using Memory Space	2014-05-29 15:50:30 +02:00
dell_rbu.txt
devices.txt	Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media	2014-04-04 09:50:07 -07:00
digsig.txt
DMA-API-HOWTO.txt	Documentation: correct parameter error for dma_mapping_error	2014-09-26 11:22:29 +02:00
DMA-API.txt	DMA-API: Capitalize "CPU" consistently	2014-05-26 17:28:27 -06:00
DMA-attributes.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
dma-buf-sharing.txt	Documentation/dma-buf-sharing.txt: update API descriptions	2014-08-28 11:57:24 +05:30
DMA-ISA-LPC.txt	DMA-API: Clarify physical/bus address distinction	2014-05-20 16:54:21 -06:00
dontdiff	Documentation: LLVMLinux: Update Documentation/dontdiff	2014-04-09 13:44:34 -07:00
dynamic-debug-howto.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
edac.txt	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial into next	2014-06-04 08:50:34 -07:00
efi-stub.txt	doc: arm64: add description of EFI stub support	2014-04-30 19:57:05 +01:00
eisa.txt
email-clients.txt	Documentation/email-clients.txt: add info about Claws Mail	2014-12-02 11:55:29 -05:00
flexible-arrays.txt
futex-requeue-pi.txt	doc: fix double words	2014-03-21 13:16:58 +01:00
gcov.txt	gcov: compile specific gcov implementation based on gcc version	2013-11-13 12:09:34 +09:00
highuid.txt
HOWTO	Documentation: remove outdated references to the linux-next wiki	2014-10-28 09:06:11 -04:00
hsi.txt	Documentation: HSI: Add some general description for the HSI subsystem	2014-05-04 09:49:46 +02:00
hw_random.txt
hwspinlock.txt
init.txt
initrd.txt
intel_txt.txt
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt	doc: fix some typos	2013-12-02 14:48:28 +01:00
iostats.txt
IPMI.txt	ipmi: Add SMBus interface driver (SSIF)	2014-12-11 15:04:11 -06:00
IRQ-affinity.txt
IRQ-domain.txt	irqdomain: Introduce new interfaces to support hierarchy irqdomains	2014-11-23 13:01:45 +01:00
IRQ.txt
irqflags-tracing.txt	asm/system.h: clean asm/system.h from docs	2014-04-07 16:36:11 -07:00
isapnp.txt
java.txt	Documentation: update java sample wrapper for java 7	2014-05-25 12:39:00 -07:00
kernel-doc-nano-HOWTO.txt
kernel-docs.txt
kernel-parameters.txt	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2015-01-27 16:59:56 -08:00
kernel-per-CPU-kthreads.txt	Documentation/kernel-per-CPU-kthreads.txt: Workqueue affinity	2014-02-17 14:56:08 -08:00
kmemcheck.txt	doc: fix double words	2014-03-21 13:16:58 +01:00
kmemleak.txt	Documentation: Add CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF case	2014-10-24 13:59:03 -04:00
kobject.txt	kobject: grammar fix	2014-12-08 09:07:11 -05:00
kprobes.txt	Documentation/kprobes: add s390 to list of supported architectures	2014-09-09 08:53:27 +02:00
kref.txt
kselftest.txt	kselftest: Move the docs to the Documentation dir	2014-11-24 10:49:54 -07:00
ldm.txt
local_ops.txt	percpu: update local_ops.txt to reflect this_cpu operations	2014-12-13 12:42:53 -08:00
lockup-watchdogs.txt	lockup-watchdogs: Fix a typo	2014-08-26 09:35:52 +02:00
logo.gif
logo.txt
lzo.txt	Documentation: lzo: document part of the encoding	2014-09-28 11:08:00 +02:00
magic-number.txt	Documentation/serial: Delete obsolete driver documentation	2014-04-16 14:20:34 -07:00
mailbox.txt	Documentation: Fix a typo in mailbox.txt	2014-11-03 11:54:50 -05:00
Makefile	Documentation: add makefiles for more targets	2014-09-26 11:02:56 +02:00
ManagementStyle
md.txt	doc: fix some typos in documentations	2013-12-02 14:45:19 +01:00
media-framework.txt
memory-barriers.txt	arch: Add lightweight memory barriers dma_rmb() and dma_wmb()	2014-12-11 21:15:06 -05:00
memory-hotplug.txt	memory-hotplug: add sysfs valid_zones attribute	2014-10-09 22:25:52 -04:00
module-signing.txt	Nothing major: the stricter permissions checking for sysfs broke	2014-04-06 09:38:07 -07:00
mono.txt
nommu-mmap.txt
numastat.txt
oops-tracing.txt	panic: add TAINT_SOFTLOCKUP	2014-08-08 15:57:24 -07:00
padata.txt
parport-lowlevel.txt
parport.txt
percpu-rw-semaphore.txt
phy.txt	phy: improved lookup method	2014-11-21 19:48:50 +05:30
pi-futex.txt
pinctrl.txt	pinctrl: clean up after enable refactoring	2014-09-04 10:05:07 +02:00
pnp.txt
preempt-locking.txt
printk-formats.txt	lib/vsprintf: add %*pE[achnops] format specifier	2014-10-14 02:18:26 +02:00
pwm.txt	pwm: modify PWM_LOOKUP to initialize all struct pwm_lookup members	2014-05-21 11:19:36 +02:00
ramoops.txt	pstore-ram: Allow optional mapping with pgprot_noncached	2014-12-11 13:38:31 -08:00
rbtree.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
remoteproc.txt
rfkill.txt	rfkill: document rfkill module parameters	2015-01-09 23:22:12 +01:00
robust-futex-ABI.txt	Documentation/robust-futex-API: Count properly to 4	2013-11-30 14:08:28 +01:00
robust-futexes.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
rpmsg.txt
rtc.txt
SAK.txt
SecurityBugs
serial-console.txt
sgi-ioc4.txt
SM501.txt
smsc_ece1099.txt
sparse.txt
stable_api_nonsense.txt
stable_kernel_rules.txt	stable_kernel_rules: Add pointer to netdev-FAQ for network patches	2014-07-09 15:54:27 -07:00
static-keys.txt	doc: fix some typos in documentations	2013-12-02 14:45:19 +01:00
SubmitChecklist
SubmittingDrivers	doc: SubmittingPatches: remove dead link, kerneltrap.org no longer works	2014-06-19 15:15:27 +02:00
SubmittingPatches	Documentation/SubmittingPatches: Reported-by tags and permission	2014-10-29 08:56:46 -04:00
svga.txt
sysfs-rules.txt	Documentation/sysfs-rules.txt: Add device attribute error code documentation	2014-09-19 14:44:51 -07:00
sysrq.txt
this_cpu_ops.txt	Docs: this_cpu_ops: remove redundant add forms	2014-09-26 11:03:00 +02:00
unaligned-memory-access.txt	ether_addr_equal: Optimize implementation, remove unused compare_ether_addr	2013-12-06 16:37:43 -05:00
unicode.txt
unshare.txt
vfio.txt	drivers/vfio: EEH support for VFIO PCI device	2014-08-05 15:28:48 +10:00
VGA-softcursor.txt
vgaarbiter.txt
video-output.txt
vme_api.txt	VME: Rename vme_slot_get to avoid confusion with reference counting	2013-12-03 11:15:58 -08:00
volatile-considered-harmful.txt
workqueue.txt
xillybus.txt	xillybus: Move out of staging	2014-09-23 23:44:16 -07:00
xz.txt
zorro.txt	zorro/UAPI: Disintegrate include/linux/zorro*.h	2013-11-26 11:09:08 +01:00