In certain 802.11 wireless deployments, there will be ARP proxies
that use knowledge of the network to correctly answer requests.
To prevent gratuitous ARP frames on the shared medium from being
a problem, on such deployments wireless needs to drop them.
Enable this by providing an option called "drop_gratuitous_arp".
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 4078228159c9f54cca7347a8bdace29f2abdef65)
Change-Id: I8772dbd7471085878f8b4161eb2a056d79b8b232
In order to solve a problem with 802.11, the so-called hole-196 attack,
add an option (sysctl) called "drop_unicast_in_l2_multicast" which, if
enabled, causes the stack to drop IPv4 unicast packets encapsulated in
link-layer multi- or broadcast frames. Such frames can (as an attack)
be created by any member of the same wireless network and transmitted
as valid encrypted frames since the symmetric key for broadcast frames
is shared between all stations.
Additionally, enabling this option provides compliance with a SHOULD
clause of RFC 1122.
Change-Id: I8de9fa5bdbea0556802f2ee553d0e73c1349213e
Reviewed-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In order to solve a problem with 802.11, the so-called hole-196 attack,
add an option (sysctl) called "drop_unicast_in_l2_multicast" which, if
enabled, causes the stack to drop IPv6 unicast packets encapsulated in
link-layer multi- or broadcast frames. Such frames can (as an attack)
be created by any member of the same wireless network and transmitted
as valid encrypted frames since the symmetric key for broadcast frames
is shared between all stations.
Reviewed-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit dede82143bf1bbf92ea73a519bb0298b19c56cb9)
Change-Id: I76c8f84b53e95c40ad3c2b5adac0ec4964cc920c
commit 5f3e2bf008c2221478101ee72f5cb4654b9fc363 upstream.
Some TCP peers announce a very small MSS option in their SYN and/or
SYN/ACK messages.
This forces the stack to send packets with a very high network/cpu
overhead.
Linux has enforced a minimal value of 48. Since this value includes
the size of TCP options, and that the options can consume up to 40
bytes, this means that each segment can include only 8 bytes of payload.
In some cases, it can be useful to increase the minimal value
to a saner value.
We still let the default to 48 (TCP_MIN_SND_MSS), for compatibility
reasons.
Note that TCP_MAXSEG socket option enforces a minimal value
of (TCP_MIN_MSS). David Miller increased this minimal value
in commit c39508d6f1 ("tcp: Make TCP_MAXSEG minimum more correct.")
from 64 to 88.
We might in the future merge TCP_MIN_SND_MSS and TCP_MIN_MSS.
CVE-2019-11479 -- tcp mss hardcoded to 48
Signed-off-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Jonathan Looney <jtl@netflix.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Bruce Curtis <brucec@netflix.com>
Cc: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[BACKPORT to 3.10: use previous sysctrl method]
Signed-off-by: syphyr@gmail.com
This commit adds a new sysctl accept_ra_rt_info_min_plen that
defines the minimum acceptable prefix length of Route Information
Options. The new sysctl is intended to be used together with
accept_ra_rt_info_max_plen to configure a range of acceptable
prefix lengths. It is useful to prevent misconfigurations from
unintentionally blackholing too much of the IPv6 address space
(e.g., home routers announcing RIOs for fc00::/7, which is
incorrect).
[backport of net-next bbea124bc99df968011e76eba105fe964a4eceab]
Bug: 33333670
Test: net_test passes
Change-Id: I5be36ef0e71b4fa9083d7aad2cbb00dd281d778f
Signed-off-by: Joel Scherpelz <jscherpelz@google.com>
Acked-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Git-commit: 161e88ebebc748d1fa51055fc31be6c98db3316e
Git-repo: https://android.googlesource.com/kernel/common.git
Signed-off-by: Srinivasarao P <spathi@codeaurora.org>
Add a sysctl that causes an interface's optimistic addresses
to be considered equivalent to other non-deprecated addresses
for source address selection purposes. Preferred addresses
will still take precedence over optimistic addresses, subject
to other ranking in the source address selection algorithm.
This is useful where different interfaces are connected to
different networks from different ISPs (e.g., a cell network
and a home wifi network).
The current behaviour complies with RFC 3484/6724, and it
makes sense if the host has only one interface, or has
multiple interfaces on the same network (same or cooperating
administrative domain(s), but not in the multiple distinct
networks case.
For example, if a mobile device has an IPv6 address on an LTE
network and then connects to IPv6-enabled wifi, while the wifi
IPv6 address is undergoing DAD, IPv6 connections will try use
the wifi default route with the LTE IPv6 address, and will get
stuck until they time out.
Also, because optimistic nodes can receive frames, issue
an RTM_NEWADDR as soon as DAD starts (with the IFA_F_OPTIMSTIC
flag appropriately set). A second RTM_NEWADDR is sent if DAD
completes (the address flags have changed), otherwise an
RTM_DELADDR is sent.
Also: add an entry in ip-sysctl.txt for optimistic_dad
[cherry-pick of net-next 7fd2561e4ebdd070ebba6d3326c4c5b13942323f]
Change-Id: I68bfdd36823c4d51c46b8c30a89322806a5e7531
Signed-off-by: Erik Kline <ek@google.com>
Acked-by: Lorenzo Colitti <lorenzo@google.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Bug: 17769720
Git-commit: 2ce95507d5ce6a5d3fd7993c35667a98c2f11f3b
Git-repo: https://android.googlesource.com/kernel/common/
Signed-off-by: Ashwanth Goli <ashwanth@codeaurora.org>
Per RFC 6724, section 4, "Candidate Source Addresses":
It is RECOMMENDED that the candidate source addresses be the set
of unicast addresses assigned to the interface that will be used
to send to the destination (the "outgoing" interface).
Add a sysctl to enable this behaviour.
Signed-off-by: Erik Kline <ek@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[Simplified back-port of net-next 3985e8a3611a93bb36789f65db862e5700aab65e]
Bug: 19470192
Bug: 21832279
Bug: 22464419
Change-Id: Ib74ef945dcabe64215064f15ee1660b6524d65ce
Conflicts:
include/linux/ipv6.h
include/uapi/linux/ipv6.h
net/ipv6/addrconf.c
Reserved ports may have some special use cases which are not suitable
for use by general userspace applications. Currently, ports specified
in ip_local_reserved_ports will not be returned only in case of
automatic port assignment.
Add a boolean sysctl flag 'reserved_port_bind'. Default value is 1
which preserves the existing behavior. Setting the value to 0 will
prevent userspace applications from binding to these ports even when
they are explicitly requested.
BUG=20663075
Change-Id: Ib1071ca5bd437cd3c4f71b56147e4858f3b9ebec
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: Mekala Natarajan <mekalan@codeaurora.org>
The kernel forcefully applies MTU values received in router
advertisements provided the new MTU is less than the current. This
behavior is undesirable when the user space is managing the MTU. Instead
a sysctl flag 'accept_ra_mtu' is introduced such that the user space
can control whether or not RA provided MTU updates should be applied.
The default behavior is unchanged; user space must explicitly set this flag
to 0 for RA MTUs to be ignored.
Change-Id: I9b2672d7c7804b6d5394516f451888d3ac8d7803
Signed-off-by: Harout Hedeshian <harouth@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
When using mark-based routing, sockets returned from accept()
may need to be marked differently depending on the incoming
connection request.
This is the case, for example, if different socket marks identify
different networks: a listening socket may want to accept
connections from all networks, but each connection should be
marked with the network that the request came in on, so that
subsequent packets are sent on the correct network.
This patch adds a sysctl to mark TCP sockets based on the fwmark
of the incoming SYN packet. If enabled, and an unmarked socket
receives a SYN, then the SYN packet's fwmark is written to the
connection's inet_request_sock, and later written back to the
accepted socket when the connection is established. If the
socket already has a nonzero mark, then the behaviour is the same
as it is today, i.e., the listening socket's fwmark is used.
Black-box tested using user-mode linux:
- IPv4/IPv6 SYN+ACK, FIN, etc. packets are routed based on the
mark of the incoming SYN packet.
- The socket returned by accept() is marked with the mark of the
incoming SYN packet.
- Tested with syncookies=1 and syncookies=2.
Change-Id: I26bc1eceefd2c588d73b921865ab70e4645ade57
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
Git-commit: 6ba3a0e3b112bdb47858e97aa763706ba26ca5ea
Git-repo: https://android.googlesource.com/kernel/common.git
Signed-off-by: Ian Maund <imaund@codeaurora.org>
Currently, routing lookups used for Path PMTU Discovery in
absence of a socket or on unmarked sockets use a mark of 0.
This causes PMTUD not to work when using routing based on
netfilter fwmark mangling and fwmark ip rules, such as:
iptables -j MARK --set-mark 17
ip rule add fwmark 17 lookup 100
This patch causes these route lookups to use the fwmark from the
received ICMP error when the fwmark_reflect sysctl is enabled.
This allows the administrator to make PMTUD work by configuring
appropriate fwmark rules to mark the inbound ICMP packets.
Black-box tested using user-mode linux by pointing different
fwmarks at routing tables egressing on different interfaces, and
using iptables mangling to mark packets inbound on each interface
with the interface's fwmark. ICMPv4 and ICMPv6 PMTU discovery
work as expected when mark reflection is enabled and fail when
it is disabled.
Change-Id: Id7fefb7ec1ff7f5142fba43db1960b050e0dfaec
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
Git-commit: 2cf4347e486ca01b5ca6429b50e79b93de07adf8
Git-repo: https://android.googlesource.com/kernel/common.git
Signed-off-by: Ian Maund <imaund@codeaurora.org>
Kernel-originated IP packets that have no user socket associated
with them (e.g., ICMP errors and echo replies, TCP RSTs, etc.)
are emitted with a mark of zero. Add a sysctl to make them have
the same mark as the packet they are replying to.
This allows an administrator that wishes to do so to use
mark-based routing, firewalling, etc. for these replies by
marking the original packets inbound.
Tested using user-mode linux:
- ICMP/ICMPv6 echo replies and errors.
- TCP RST packets (IPv4 and IPv6).
Change-Id: I6873d973196797bcf32e2e91976df647c7e8b85a
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
Git-commit: 5a87fa6a43733e241406e8d62fe28fdc0735bf93
Git-repo: https://android.googlesource.com/kernel/common.git
[imaund@codeaurora.org: Resolve trivial merge conflicts]
Signed-off-by: Ian Maund <imaund@codeaurora.org>
The following commits have been reverted from this merge, as they are
known to introduce new bugs and are currently incompatible with our
audio implementation. Investigation of these commits is ongoing, and
they are expected to be brought in at a later time:
86e6de7 ALSA: compress: fix drain calls blocking other compress functions (v6)
16442d4 ALSA: compress: fix drain calls blocking other compress functions
This merge commit also includes a change in block, necessary for
compilation. Upstream has modified elevator_init_fn to prevent race
conditions, requring updates to row_init_queue and test_init_queue.
* commit 'v3.10.28': (1964 commits)
Linux 3.10.28
ARM: 7938/1: OMAP4/highbank: Flush L2 cache before disabling
drm/i915: Don't grab crtc mutexes in intel_modeset_gem_init()
serial: amba-pl011: use port lock to guard control register access
mm: Make {,set}page_address() static inline if WANT_PAGE_VIRTUAL
md/raid5: Fix possible confusion when multiple write errors occur.
md/raid10: fix two bugs in handling of known-bad-blocks.
md/raid10: fix bug when raid10 recovery fails to recover a block.
md: fix problem when adding device to read-only array with bitmap.
drm/i915: fix DDI PLLs HW state readout code
nilfs2: fix segctor bug that causes file system corruption
thp: fix copy_page_rep GPF by testing is_huge_zero_pmd once only
ftrace/x86: Load ftrace_ops in parameter not the variable holding it
SELinux: Fix possible NULL pointer dereference in selinux_inode_permission()
writeback: Fix data corruption on NFS
hwmon: (coretemp) Fix truncated name of alarm attributes
vfs: In d_path don't call d_dname on a mount point
staging: comedi: adl_pci9111: fix incorrect irq passed to request_irq()
staging: comedi: addi_apci_1032: fix subdevice type/flags bug
mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully
GFS2: Increase i_writecount during gfs2_setattr_chown
perf/x86/amd/ibs: Fix waking up from S3 for AMD family 10h
perf scripting perl: Fix build error on Fedora 12
ARM: 7815/1: kexec: offline non panic CPUs on Kdump panic
Linux 3.10.27
sched: Guarantee new group-entities always have weight
sched: Fix hrtimer_cancel()/rq->lock deadlock
sched: Fix cfs_bandwidth misuse of hrtimer_expires_remaining
sched: Fix race on toggling cfs_bandwidth_used
x86, fpu, amd: Clear exceptions in AMD FXSAVE workaround
netfilter: nf_nat: fix access to uninitialized buffer in IRC NAT helper
SCSI: sd: Reduce buffer size for vpd request
intel_pstate: Add X86_FEATURE_APERFMPERF to cpu match parameters.
mac80211: move "bufferable MMPDU" check to fix AP mode scan
ACPI / Battery: Add a _BIX quirk for NEC LZ750/LS
ACPI / TPM: fix memory leak when walking ACPI namespace
mfd: rtsx_pcr: Disable interrupts before cancelling delayed works
clk: exynos5250: fix sysmmu_mfc{l,r} gate clocks
clk: samsung: exynos5250: Add CLK_IGNORE_UNUSED flag for the sysreg clock
clk: samsung: exynos4: Correct SRC_MFC register
clk: clk-divider: fix divisor > 255 bug
ahci: add PCI ID for Marvell 88SE9170 SATA controller
parisc: Ensure full cache coherency for kmap/kunmap
drm/nouveau/bios: make jump conditional
ARM: shmobile: mackerel: Fix coherent DMA mask
ARM: shmobile: armadillo: Fix coherent DMA mask
ARM: shmobile: kzm9g: Fix coherent DMA mask
ARM: dts: exynos5250: Fix MDMA0 clock number
ARM: fix "bad mode in ... handler" message for undefined instructions
ARM: fix footbridge clockevent device
net: Loosen constraints for recalculating checksum in skb_segment()
bridge: use spin_lock_bh() in br_multicast_set_hash_max
netpoll: Fix missing TXQ unlock and and OOPS.
net: llc: fix use after free in llc_ui_recvmsg
virtio-net: fix refill races during restore
virtio_net: don't leak memory or block when too many frags
virtio-net: make all RX paths handle errors consistently
virtio_net: fix error handling for mergeable buffers
vlan: Fix header ops passthru when doing TX VLAN offload.
net: rose: restore old recvmsg behavior
rds: prevent dereference of a NULL device
ipv6: always set the new created dst's from in ip6_rt_copy
net: fec: fix potential use after free
hamradio/yam: fix info leak in ioctl
drivers/net/hamradio: Integer overflow in hdlcdrv_ioctl()
net: inet_diag: zero out uninitialized idiag_{src,dst} fields
ip_gre: fix msg_name parsing for recvfrom/recvmsg
net: unix: allow bind to fail on mutex lock
ipv6: fix illegal mac_header comparison on 32bit
netvsc: don't flush peers notifying work during setting mtu
tg3: Initialize REG_BASE_ADDR at PCI config offset 120 to 0
net: unix: allow set_peek_off to fail
net: drop_monitor: fix the value of maxattr
ipv6: don't count addrconf generated routes against gc limit
packet: fix send path when running with proto == 0
virtio: delete napi structures from netdev before releasing memory
macvtap: signal truncated packets
tun: update file current position
macvtap: update file current position
macvtap: Do not double-count received packets
rds: prevent BUG_ON triggered on congestion update to loopback
net: do not pretend FRAGLIST support
IPv6: Fixed support for blackhole and prohibit routes
HID: Revert "Revert "HID: Fix logitech-dj: missing Unifying device issue""
gpio-rcar: R-Car GPIO IRQ share interrupt
clocksource: em_sti: Set cpu_possible_mask to fix SMP broadcast
irqchip: renesas-irqc: Fix irqc_probe error handling
Linux 3.10.26
sh: add EXPORT_SYMBOL(min_low_pfn) and EXPORT_SYMBOL(max_low_pfn) to sh_ksyms_32.c
ext4: fix bigalloc regression
arm64: Use Normal NonCacheable memory for writecombine
arm64: Do not flush the D-cache for anonymous pages
arm64: Avoid cache flushing in flush_dcache_page()
ARM: KVM: arch_timers: zero CNTVOFF upon return to host
ARM: hyp: initialize CNTVOFF to zero
clocksource: arch_timer: use virtual counters
arm64: Remove unused cpu_name ascii in arch/arm64/mm/proc.S
arm64: dts: Reserve the memory used for secondary CPU release address
arm64: check for number of arguments in syscall_get/set_arguments()
arm64: fix possible invalid FPSIMD initialization state
...
Change-Id: Ia0e5d71b536ab49ec3a1179d59238c05bdd03106
Signed-off-by: Ian Maund <imaund@codeaurora.org>
[ Upstream commit 98e09386c0ef4dfd48af7ba60ff908f0d525cdee ]
After commit c9eeec26e32e ("tcp: TSQ can use a dynamic limit"), several
users reported throughput regressions, notably on mvneta and wifi
adapters.
802.11 AMPDU requires a fair amount of queueing to be effective.
This patch partially reverts the change done in tcp_write_xmit()
so that the minimal amount is sysctl_tcp_limit_output_bytes.
It also remove the use of this sysctl while building skb stored
in write queue, as TSO autosizing does the right thing anyway.
Users with well behaving NICS and correct qdisc (like sch_fq),
can then lower the default sysctl_tcp_limit_output_bytes value from
128KB to 8KB.
This new usage of sysctl_tcp_limit_output_bytes permits each driver
authors to check how their driver performs when/if the value is set
to a minimum of 4KB.
Normally, line rate for a single TCP flow should be possible,
but some drivers rely on timers to perform TX completion and
too long TX completion delays prevent reaching full throughput.
Fixes: c9eeec26e32e ("tcp: TSQ can use a dynamic limit")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Sujith Manoharan <sujith@msujith.org>
Reported-by: Arnaud Ebalard <arno@natisbad.org>
Tested-by: Sujith Manoharan <sujith@msujith.org>
Cc: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commits 6d36824e730f247b602c90e8715a792003e3c5a7,
02cf4ebd82ff0ac7254b88e466820a290ed8289a, and parts of
7eec4174ff29cd42f2acfae8112f51c228545d40 ]
After hearing many people over past years complaining against TSO being
bursty or even buggy, we are proud to present automatic sizing of TSO
packets.
One part of the problem is that tcp_tso_should_defer() uses an heuristic
relying on upcoming ACKS instead of a timer, but more generally, having
big TSO packets makes little sense for low rates, as it tends to create
micro bursts on the network, and general consensus is to reduce the
buffering amount.
This patch introduces a per socket sk_pacing_rate, that approximates
the current sending rate, and allows us to size the TSO packets so
that we try to send one packet every ms.
This field could be set by other transports.
Patch has no impact for high speed flows, where having large TSO packets
makes sense to reach line rate.
For other flows, this helps better packet scheduling and ACK clocking.
This patch increases performance of TCP flows in lossy environments.
A new sysctl (tcp_min_tso_segs) is added, to specify the
minimal size of a TSO packet (default being 2).
A follow-up patch will provide a new packet scheduler (FQ), using
sk_pacing_rate as an input to perform optional per flow pacing.
This explains why we chose to set sk_pacing_rate to twice the current
rate, allowing 'slow start' ramp up.
sk_pacing_rate = 2 * cwnd * mss / srtt
v2: Neal Cardwell reported a suspect deferring of last two segments on
initial write of 10 MSS, I had to change tcp_tso_should_defer() to take
into account tp->xmit_size_goal_segs
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Van Jacobson <vanj@google.com>
Cc: Tom Herbert <therbert@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This new mode allows Neighbor discovery packets to be sent to userspace
without regards to the state of the forwarding setting. Without this, NDP
packets addressed to the host are still received, but those for other
addresses are not.
Enabling this mode allows NDP proxying to be performed from userspace.
Change-Id: I69b7a7c0c42e3253c42d6f2e163c0ce1d848aed6
Signed-off-by: Jaime Lopez <jaimel@codeaurora.org>
Added new procfs flag to toggle the automatic addition of prefix
routes on a per device basis. The new flag is accept_ra_prefix_route.
Defaults to 1 as to not break existing behavior.
Change-Id: If25493890c7531c27f5b2c4855afebbbbf5d072a
CRs-Fixed: 435320
Acked-by: Harout S. Hedeshian <harouth@qti.qualcomm.com>
Signed-off-by: Tianyi Gou <tgou@codeaurora.org>
syncookies is on for default since in commit e994b7c901
(tcp: Don't make syn cookies initial setting depend on CONFIG_SYSCTL).
And fix a typo of CONFIG_SYN_COOKIES.
Signed-off-by: Shan Wei <davidshan@tencent.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch implements F-RTO (foward RTO recovery):
When the first retransmission after timeout is acknowledged, F-RTO
sends new data instead of old data. If the next ACK acknowledges
some never-retransmitted data, then the timeout was spurious and the
congestion state is reverted. Otherwise if the next ACK selectively
acknowledges the new data, then the timeout was genuine and the
loss recovery continues. This idea applies to recurring timeouts
as well. While F-RTO sends different data during timeout recovery,
it does not (and should not) change the congestion control.
The implementaion follows the three steps of SACK enhanced algorithm
(section 3) in RFC5682. Step 1 is in tcp_enter_loss(). Step 2 and
3 are in tcp_process_loss(). The basic version is not supported
because SACK enhanced version also works for non-SACK connections.
The new implementation is functionally in parity with the old F-RTO
implementation except the one case where it increases undo events:
In addition to the RFC algorithm, a spurious timeout may be detected
without sending data in step 2, as long as the SACK confirms not
all the original data are dropped. When this happens, the sender
will undo the cwnd and perhaps enter fast recovery instead. This
additional check increases the F-RTO undo events by 5x compared
to the prior implementation on Google Web servers, since the sender
often does not have new data to send for HTTP.
Note F-RTO may detect spurious timeout before Eifel with timestamps
does so.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The patch series refactor the F-RTO feature (RFC4138/5682).
This is to simplify the loss recovery processing. Existing F-RTO
was developed during the experimental stage (RFC4138) and has
many experimental features. It takes a separate code path from
the traditional timeout processing by overloading CA_Disorder
instead of using CA_Loss state. This complicates CA_Disorder state
handling because it's also used for handling dubious ACKs and undos.
While the algorithm in the RFC does not change the congestion control,
the implementation intercepts congestion control in various places
(e.g., frto_cwnd in tcp_ack()).
The new code implements newer F-RTO RFC5682 using CA_Loss processing
path. F-RTO becomes a small extension in the timeout processing
and interfaces with congestion control and Eifel undo modules.
It lets congestion control (module) determines how many to send
independently. F-RTO only chooses what to send in order to detect
spurious retranmission. If timeout is found spurious it invokes
existing Eifel undo algorithms like DSACK or TCP timestamp based
detection.
The first patch removes all F-RTO code except the sysctl_tcp_frto is
left for the new implementation. Since CA_EVENT_FRTO is removed, TCP
westwood now computes ssthresh on regular timeout CA_EVENT_LOSS event.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
TCPCT uses option-number 253, reserved for experimental use and should
not be used in production environments.
Further, TCPCT does not fully implement RFC 6013.
As a nice side-effect, removing TCPCT increases TCP's performance for
very short flows:
Doing an apache-benchmark with -c 100 -n 100000, sending HTTP-requests
for files of 1KB size.
before this patch:
average (among 7 runs) of 20845.5 Requests/Second
after:
average (among 7 runs) of 21403.6 Requests/Second
Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
The default value is 128, not 256
#grep gc_thresh1 net/ -rI
net/decnet/dn_neigh.c: .gc_thresh1 = 128,
net/ipv6/ndisc.c: .gc_thresh1 = 128,
net/ipv4/arp.c: .gc_thresh1 = 128,
Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch series implement the Tail loss probe (TLP) algorithm described
in http://tools.ietf.org/html/draft-dukkipati-tcpm-tcp-loss-probe-01. The
first patch implements the basic algorithm.
TLP's goal is to reduce tail latency of short transactions. It achieves
this by converting retransmission timeouts (RTOs) occuring due
to tail losses (losses at end of transactions) into fast recovery.
TLP transmits one packet in two round-trips when a connection is in
Open state and isn't receiving any ACKs. The transmitted packet, aka
loss probe, can be either new or a retransmission. When there is tail
loss, the ACK from a loss probe triggers FACK/early-retransmit based
fast recovery, thus avoiding a costly RTO. In the absence of loss,
there is no change in the connection state.
PTO stands for probe timeout. It is a timer event indicating
that an ACK is overdue and triggers a loss probe packet. The PTO value
is set to max(2*SRTT, 10ms) and is adjusted to account for delayed
ACK timer when there is only one oustanding packet.
TLP Algorithm
On transmission of new data in Open state:
-> packets_out > 1: schedule PTO in max(2*SRTT, 10ms).
-> packets_out == 1: schedule PTO in max(2*RTT, 1.5*RTT + 200ms)
-> PTO = min(PTO, RTO)
Conditions for scheduling PTO:
-> Connection is in Open state.
-> Connection is either cwnd limited or no new data to send.
-> Number of probes per tail loss episode is limited to one.
-> Connection is SACK enabled.
When PTO fires:
new_segment_exists:
-> transmit new segment.
-> packets_out++. cwnd remains same.
no_new_packet:
-> retransmit the last segment.
Its ACK triggers FACK or early retransmit based recovery.
ACK path:
-> rearm RTO at start of ACK processing.
-> reschedule PTO if need be.
In addition, the patch includes a small variation to the Early Retransmit
(ER) algorithm, such that ER and TLP together can in principle recover any
N-degree of tail loss through fast recovery. TLP is controlled by the same
sysctl as ER, tcp_early_retrans sysctl.
tcp_early_retrans==0; disables TLP and ER.
==1; enables RFC5827 ER.
==2; delayed ER.
==3; TLP and delayed ER. [DEFAULT]
==4; TLP only.
The TLP patch series have been extensively tested on Google Web servers.
It is most effective for short Web trasactions, where it reduced RTOs by 15%
and improved HTTP response time (average by 6%, 99th percentile by 10%).
The transmitted probes account for <0.5% of the overall transmissions.
Signed-off-by: Nandita Dukkipati <nanditad@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
TCP Appropriate Byte Count was added by me, but later disabled.
There is no point in maintaining it since it is a potential source
of bugs and Linux already implements other better window protection
heuristics.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since we have removed NCE (Neighbour Cache Entry) reference from
routing entries, the only refcnt holders of an NCE are its timer
(if running) and its owner table, in usual cases. As a result,
neigh_periodic_work() purges NCEs over and over again even for
gateways.
It does not make sense to purge entries, if number of them is
very small, so keep them. The minimum number of entries to keep
is specified by gc_thresh1.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
Documentation/networking/ip-sysctl.txt
drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
Both conflicts were simply overlapping context.
A build fix for qlcnic is in here too, simply removing the added
devinit annotations which no longer exist.
Signed-off-by: David S. Miller <davem@davemloft.net>
Recent commit (commit 7e3a2dc529 doc: make the description of how tcp_ecn
works more explicit and clear ) clarified the behavior of tcp_ecn sysctl
variable but description is inconsistent. When requested by incoming conections,
ECN is enabled with not just tcp_ecn = 2 but also with tcp_ecn = 1.
This patch makes it clear that with tcp_ecn = 1, ECN is enabled when requested
by incoming connections.
Also fix spelling of 'incoming'.
Signed-off-by: Vijay Subramanian <subramanian.vijay@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I slipped in a new sysctl without proper documentation. I would like to
make up for this now.
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The description for tcp_fin_timeout should be tigher and more clear.
In addition to being tighter, we should make the spelling of the
state name consistent with what utilities report, remove the now
dated reference to 2.2 and put the default in the consistent place.
Signed-off-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
'secluded' is used to describe places, not suitable here.
Suggested-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Shan Wei <davidshan@tencent.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make the description of how tcp_ecn works a bit more explicit and clear.
Signed-off-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently sctp allows for the optional use of md5 of sha1 hmac algorithms to
generate cookie values when establishing new connections via two build time
config options. Theres no real reason to make this a static selection. We can
add a sysctl that allows for the dynamic selection of these algorithms at run
time, with the default value determined by the corresponding crypto library
availability.
This comes in handy when, for example running a system in FIPS mode, where use
of md5 is disallowed, but SHA1 is permitted.
Note: This new sysctl has no corresponding socket option to select the cookie
hmac algorithm. I chose not to implement that intentionally, as RFC 6458
contains no option for this value, and I opted not to pollute the socket option
namespace.
Change notes:
v2)
* Updated subject to have the proper sctp prefix as per Dave M.
* Replaced deafult selection options with new options that allow
developers to explicitly select available hmac algs at build time
as per suggestion by Vlad Y.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Vlad Yasevich <vyasevich@gmail.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: netdev@vger.kernel.org
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds all the necessary data structure and support
functions to implement TFO server side. It also documents a number
of flags for the sysctl_tcp_fastopen knob, and adds a few Linux
extension MIBs.
In addition, it includes the following:
1. a new TCP_FASTOPEN socket option an application must call to
supply a max backlog allowed in order to enable TFO on its listener.
2. A number of key data structures:
"fastopen_rsk" in tcp_sock - for a big socket to access its
request_sock for retransmission and ack processing purpose. It is
non-NULL iff 3WHS not completed.
"fastopenq" in request_sock_queue - points to a per Fast Open
listener data structure "fastopen_queue" to keep track of qlen (# of
outstanding Fast Open requests) and max_qlen, among other things.
"listener" in tcp_request_sock - to point to the original listener
for book-keeping purpose, i.e., to maintain qlen against max_qlen
as part of defense against IP spoofing attack.
3. various data structure and functions, many in tcp_fastopen.c, to
support server side Fast Open cookie operations, including
/proc/sys/net/ipv4/tcp_fastopen_key to allow manual rekeying.
Signed-off-by: H.K. Jerry Chu <hkchu@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 9ad7c049 ("tcp: RFC2988bis + taking RTT sample from 3WHS for
the passive open side") changed the initRTO from 3secs to 1sec in
accordance to RFC6298 (former RFC2988bis). This reduced the time till
the last SYN retransmission packet gets sent from 93secs to 31secs.
RFC1122 is stating that the retransmission should be done for at least 3
minutes, but this seems to be quite high.
"However, the values of R1 and R2 may be different for SYN
and data segments. In particular, R2 for a SYN segment MUST
be set large enough to provide retransmission of the segment
for at least 3 minutes. The application can close the
connection (i.e., give up on the open attempt) sooner, of
course."
This patch increases the value of TCP_SYN_RETRIES to the value of 6,
providing a retransmission window of 63secs.
The comments for SYN and SYNACK retries have also been updated to
describe the current settings. The same goes for the documentation file
"Documentation/networking/ip-sysctl.txt".
Signed-off-by: Alexander Bergmann <alex@linlab.net>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After IP route cache removal, rt_cache_rebuild_count is no longer
used.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I've seen several attempts recently made to do quick failover of sctp transports
by reducing various retransmit timers and counters. While its possible to
implement a faster failover on multihomed sctp associations, its not
particularly robust, in that it can lead to unneeded retransmits, as well as
false connection failures due to intermittent latency on a network.
Instead, lets implement the new ietf quick failover draft found here:
http://tools.ietf.org/html/draft-nishida-tsvwg-sctp-failover-05
This will let the sctp stack identify transports that have had a small number of
errors, and avoid using them quickly until their reliability can be
re-established. I've tested this out on two virt guests connected via multiple
isolated virt networks and believe its in compliance with the above draft and
works well.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Vlad Yasevich <vyasevich@gmail.com>
CC: Sridhar Samudrala <sri@us.ibm.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: linux-sctp@vger.kernel.org
CC: joe@perches.com
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In trusted networks, e.g., intranet, data-center, the client does not
need to use Fast Open cookie to mitigate DoS attacks. In cookie-less
mode, sendmsg() with MSG_FASTOPEN flag will send SYN-data regardless
of cookie availability.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sendmsg() (or sendto()) with MSG_FASTOPEN is a combo of connect(2)
and write(2). The application should replace connect() with it to
send data in the opening SYN packet.
For blocking socket, sendmsg() blocks until all the data are buffered
locally and the handshake is completed like connect() call. It
returns similar errno like connect() if the TCP handshake fails.
For non-blocking socket, it returns the number of bytes queued (and
transmitted in the SYN-data packet) if cookie is available. If cookie
is not available, it transmits a data-less SYN packet with Fast Open
cookie request option and returns -EINPROGRESS like connect().
Using MSG_FASTOPEN on connecting or connected socket will result in
simlar errno like repeating connect() calls. Therefore the application
should only use this flag on new sockets.
The buffer size of sendmsg() is independent of the MSS of the connection.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Implement the RFC 5691 mitigation against Blind
Reset attack using RST bit.
Idea is to validate incoming RST sequence,
to match RCV.NXT value, instead of previouly accepted
window : (RCV.NXT <= SEG.SEQ < RCV.NXT+RCV.WND)
If sequence is in window but not an exact match, send
a "challenge ACK", so that the other part can resend an
RST with the appropriate sequence.
Add a new sysctl, tcp_challenge_ack_limit, to limit
number of challenge ACK sent per second.
Add a new SNMP counter to count number of challenge acks sent.
(netstat -s | grep TCPChallengeACK)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Kiran Kumar Kella <kkiran@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This introduce TSQ (TCP Small Queues)
TSQ goal is to reduce number of TCP packets in xmit queues (qdisc &
device queues), to reduce RTT and cwnd bias, part of the bufferbloat
problem.
sk->sk_wmem_alloc not allowed to grow above a given limit,
allowing no more than ~128KB [1] per tcp socket in qdisc/dev layers at a
given time.
TSO packets are sized/capped to half the limit, so that we have two
TSO packets in flight, allowing better bandwidth use.
As a side effect, setting the limit to 40000 automatically reduces the
standard gso max limit (65536) to 40000/2 : It can help to reduce
latencies of high prio packets, having smaller TSO packets.
This means we divert sock_wfree() to a tcp_wfree() handler, to
queue/send following frames when skb_orphan() [2] is called for the
already queued skbs.
Results on my dev machines (tg3/ixgbe nics) are really impressive,
using standard pfifo_fast, and with or without TSO/GSO.
Without reduction of nominal bandwidth, we have reduction of buffering
per bulk sender :
< 1ms on Gbit (instead of 50ms with TSO)
< 8ms on 100Mbit (instead of 132 ms)
I no longer have 4 MBytes backlogged in qdisc by a single netperf
session, and both side socket autotuning no longer use 4 Mbytes.
As skb destructor cannot restart xmit itself ( as qdisc lock might be
taken at this point ), we delegate the work to a tasklet. We use one
tasklest per cpu for performance reasons.
If tasklet finds a socket owned by the user, it sets TSQ_OWNED flag.
This flag is tested in a new protocol method called from release_sock(),
to eventually send new segments.
[1] New /proc/sys/net/ipv4/tcp_limit_output_bytes tunable
[2] skb_orphan() is usually called at TX completion time,
but some drivers call it in their start_xmit() handler.
These drivers should at least use BQL, or else a single TCP
session can still fill the whole NIC TX ring, since TSQ will
have no effect.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Dave Taht <dave.taht@bufferbloat.net>
Cc: Tom Herbert <therbert@google.com>
Cc: Matt Mathis <mattmathis@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Nandita Dukkipati <nanditad@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Routing of 127/8 is tradtionally forbidden, we consider
packets from that address block martian when routing and do
not process corresponding ARP requests.
This is a sane default but renders a huge address space
practically unuseable.
The RFC states that no address within the 127/8 block should
ever appear on any network anywhere but it does not forbid
the use of such addresses outside of the loopback device in
particular. For example to address a pool of virtual guests
behind a load balancer.
This patch adds a new interface option 'route_localnet'
enabling routing of the 127/8 address block and processing
of ARP requests on a specific interface.
Note that for the feature to work, the default local route
covering 127/8 dev lo needs to be removed.
Example:
$ sysctl -w net.ipv4.conf.eth0.route_localnet=1
$ ip route del 127.0.0.0/8 dev lo table local
$ ip addr add 127.1.0.1/16 dev eth0
$ ip route flush cache
V2: Fix invalid check to auto flush cache (thanks davem)
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
if net.bridge.bridge-nf-filter-vlan-tagged sysctl is enabled, bridge
netfilter removes the vlan header temporarily and then feeds the packet
to ip(6)tables.
When the new "bridge-nf-pass-vlan-input-device" sysctl is on
(default off), then bridge netfilter will also set the
in-interface to the vlan interface; if such an interface exists.
This is needed to make iptables REDIRECT target work with
"vlan-on-top-of-bridge" setups and to allow use of "iptables -i" to
match the vlan device name.
Also update Documentation with current brnf default settings.
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Bart De Schuymer <bdschuym@pandora.be>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Conflicts:
drivers/net/ethernet/intel/e1000e/param.c
drivers/net/wireless/iwlwifi/iwl-agn-rx.c
drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
drivers/net/wireless/iwlwifi/iwl-trans.h
Resolved the iwlwifi conflict with mainline using 3-way diff posted
by John Linville and Stephen Rothwell. In 'net' we added a bug
fix to make iwlwifi report a more accurate skb->truesize but this
conflicted with RX path changes that happened meanwhile in net-next.
In e1000e a conflict arose in the validation code for settings of
adapter->itr. 'net-next' had more sophisticated logic so that
logic was used.
Signed-off-by: David S. Miller <davem@davemloft.net>
tcp_adv_win_scale default value is 2, meaning we expect a good citizen
skb to have skb->len / skb->truesize ratio of 75% (3/4)
In 2.6 kernels we (mis)accounted for typical MSS=1460 frame :
1536 + 64 + 256 = 1856 'estimated truesize', and 1856 * 3/4 = 1392.
So these skbs were considered as not bloated.
With recent truesize fixes, a typical MSS=1460 frame truesize is now the
more precise :
2048 + 256 = 2304. But 2304 * 3/4 = 1728.
So these skb are not good citizen anymore, because 1460 < 1728
(GRO can escape this problem because it build skbs with a too low
truesize.)
This also means tcp advertises a too optimistic window for a given
allocated rcvspace : When receiving frames, sk_rmem_alloc can hit
sk_rcvbuf limit and we call tcp_prune_queue()/tcp_collapse() too often,
especially when application is slow to drain its receive queue or in
case of losses (netperf is fast, scp is slow). This is a major latency
source.
We should adjust the len/truesize ratio to 50% instead of 75%
This patch :
1) changes tcp_adv_win_scale default to 1 instead of 2
2) increase tcp_rmem[2] limit from 4MB to 6MB to take into account
better truesize tracking and to allow autotuning tcp receive window to
reach same value than before. Note that same amount of kernel memory is
consumed compared to 2.6 kernels.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch implements RFC 5827 early retransmit (ER) for TCP.
It reduces DUPACK threshold (dupthresh) if outstanding packets are
less than 4 to recover losses by fast recovery instead of timeout.
While the algorithm is simple, small but frequent network reordering
makes this feature dangerous: the connection repeatedly enter
false recovery and degrade performance. Therefore we implement
a mitigation suggested in the appendix of the RFC that delays
entering fast recovery by a small interval, i.e., RTT/4. Currently
ER is conservative and is disabled for the rest of the connection
after the first reordering event. A large scale web server
experiment on the performance impact of ER is summarized in
section 6 of the paper "Proportional Rate Reduction for TCP”,
IMC 2011. http://conferences.sigcomm.org/imc/2011/docs/p155.pdf
Note that Linux has a similar feature called THIN_DUPACK. The
differences are THIN_DUPACK do not mitigate reorderings and is only
used after slow start. Currently ER is disabled if THIN_DUPACK is
enabled. I would be happy to merge THIN_DUPACK feature with ER if
people think it's a good idea.
ER is enabled by sysctl_tcp_early_retrans:
0: Disables ER
1: Reduce dupthresh to packets_out - 1 when outstanding packets < 4.
2: (Default) reduce dupthresh like mode 1. In addition, delay
entering fast recovery by RTT/4.
Note: mode 2 is implemented in the third part of this patch series.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
All parameter descriptions in /proc/sys/net/core/* now is separated
two places. So, merge them into Documentation/sysctl/net.txt.
Signed-off-by: Shan Wei <davidshan@tencent.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The explanation of ip_local_port_range in
Documentation/networking/ip-sysctl.txt contains several factual
errors:
- The default value of ip_local_port_range does not depend on the
amount of memory available in the system.
- tcp_tw_recycle is not enabled by default.
- 1024-4999 is not the default value.
- Etc.
Clean up the mess.
Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
Johannes Berg
Eric Dumazet
Joel Scherpelz
Erik Kline
Subash Abhinov Kasiviswanathan
Harout Hedeshian
Lorenzo Colitti
Ian Maund
Jaime Lopez
Tianyi Gou
Shan Wei
Yuchung Cheng
Christoph Paasch
Li RongQing
Nandita Dukkipati
Stephen Hemminger
YOSHIFUJI Hideaki / 吉藤英明
David S. Miller
Vijay Subramanian
stephen hemminger
Hannes Frederic Sowa
Rick Jones
Shan Wei
Neil Horman
Jerry Chu
Alex Bergmann
Eric Dumazet
Thomas Graf
Pablo Neira Ayuso
Fernando Luis Vazquez Cao