Currently mutex_is_held can only test locks in the that are global
since it takes no arguments. This prevents rhashtable from being
used in places where locks are lock, e.g., per-namespace locks.
This patch adds a parent field to mutex_is_held and rhashtable_params
so that local locks can be used (and tested).
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The rhashtable function mutex_is_held is only used when PROVE_LOCKING
is enabled. This patch makes the mutex_is_held field in rhashtable
optional depending on PROVE_LOCKING.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead of calling fou and gue functions directly from ip_tunnel
use ops for these that were previously registered. This patch adds the
logic to add and remove encapsulation operations for ip_tunnel,
and modified fou (and gue) to register with ip_tunnels.
This patch also addresses a circular dependency between ip_tunnel
and fou that was causing link errors when CONFIG_NET_IP_TUNNEL=y
and CONFIG_NET_FOU=m. References to fou an gue have been removed from
ip_tunnel.c
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use the normal kernel debugging mechanism which also
enables dynamic_debug at the same time.
Other miscellanea:
o Remove sysctl for irda_debug
o Remove function tracing like uses (use ftrace instead)
o Coalesce formats
o Realign arguments
o Remove unnecessary OOM messages
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add helper macro for PHY drivers which do not do anything special in
module init/exit. This will allow us to eliminate a lot of boilerplate
code.
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove the two functions which are now dead code.
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch implements __dev_alloc_pages and __dev_alloc_page. These are
meant to replace the __skb_alloc_pages and __skb_alloc_page functions. The
reason for doing this is that it occurred to me that __skb_alloc_page is
supposed to be passed an sk_buff pointer, but it is NULL in all cases where
it is used. Worse is that in the case of ixgbe it is passed NULL via the
sk_buff pointer in the rx_buffer info structure which means the compiler is
not correctly stripping it out.
The naming for these functions is based on dev_alloc_skb and __dev_alloc_skb.
There was originally a netdev_alloc_page, however that was passed a
net_device pointer and this function is not so I thought it best to follow
that naming scheme since that is the same difference between dev_alloc_skb
and netdev_alloc_skb.
In the case of anything greater than order 0 it is assumed that we want a
compound page so __GFP_COMP is set for all allocations as we expect a
compound page when assigning a page frag.
The other change in this patch is to exploit the behaviors of the page
allocator in how it handles flags. So for example we can always set
__GFP_COMP and __GFP_MEMALLOC since they are ignored if they are not
applicable or are overridden by another flag.
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
And use the more common mechanisms directly.
Other miscellanea:
o Coalesce formats
o Add missing newlines
o Realign arguments
o Remove unnecessary OOM message logging as
there's a generic stack dump already on OOM.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
vlan was the only user of netif_copy_real_num_queues(),
but it no longer calls it after
commit 4af429d29b ("vlan: lockless transmit path").
So we can just remove it.
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
These are the same as net_<level>_ratelimited, so
use the more common style in the macro definition.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently there are only three neigh tables in the whole kernel:
arp table, ndisc table and decnet neigh table. What's more,
we don't support registering multiple tables per family.
Therefore we can just make these tables statically built-in.
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use the more common dynamic_debug capable net_dbg_ratelimited
and remove the LIMIT_NETDEBUG macro.
All messages are still ratelimited.
Some KERN_<LEVEL> uses are changed to KERN_DEBUG.
This may have some negative impact on messages that were
emitted at KERN_INFO that are not not enabled at all unless
DEBUG is defined or dynamic_debug is enabled. Even so,
these messages are now _not_ emitted by default.
This also eliminates the use of the net_msg_warn sysctl
"/proc/sys/net/core/warnings". For backward compatibility,
the sysctl is not removed, but it has no function. The extern
declaration of net_msg_warn is removed from sock.h and made
static in net/core/sysctl_net_core.c
Miscellanea:
o Update the sysctl documentation
o Remove the embedded uses of pr_fmt
o Coalesce format fragments
o Realign arguments
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pravin B Shelar says:
====================
Open vSwitch
Following batch of patches brings feature parity between upstream
ovs and out of tree ovs module.
Two features are added, first adds support to export egress
tunnel information for a packet. This is used to improve
visibility in network traffic. Second feature allows userspace
vswitchd process to probe ovs module features. Other patches
are optimization and code cleanup.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
When processing received traffic, pass CHECKSUM_COMPLETE status to the
stack, with calculated checksum for non TCP/UDP packets (such
as GRE or ICMP).
Although the stack expects checksum which doesn't include the pseudo
header, the HW adds it. To address that, we are subtracting the pseudo
header checksum from the checksum value provided by the HW.
In the IPv6 case, we also compute/add the IP header checksum which
is not added by the HW for such packets.
Cc: Jerry Chu <hkchu@google.com>
Signed-off-by: Shani Michaeli <shanim@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Alternative to RPS/RFS is to use hardware support for multiple
queues.
Then split a set of million of sockets into worker threads, each
one using epoll() to manage events on its own socket pool.
Ideally, we want one thread per RX/TX queue/cpu, but we have no way to
know after accept() or connect() on which queue/cpu a socket is managed.
We normally use one cpu per RX queue (IRQ smp_affinity being properly
set), so remembering on socket structure which cpu delivered last packet
is enough to solve the problem.
After accept(), connect(), or even file descriptor passing around
processes, applications can use :
int cpu;
socklen_t len = sizeof(cpu);
getsockopt(fd, SOL_SOCKET, SO_INCOMING_CPU, &cpu, &len);
And use this information to put the socket into the right silo
for optimal performance, as all networking stack should run
on the appropriate cpu, without need to send IPI (RPS/RFS).
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
John W. Linville says:
====================
pull request: wireless-next 2014-11-07
Please pull this batch of updates intended for the 3.19 stream!
For the mac80211 bits, Johannes says:
"This relatively large batch of changes is comprised of the following:
* large mac80211-hwsim changes from Ben, Jukka and a bit myself
* OCB/WAVE/11p support from Rostislav on behalf of the Czech Technical
University in Prague and Volkswagen Group Research
* minstrel VHT work from Karl
* more CSA work from Luca
* WMM admission control support in mac80211 (myself)
* various smaller fixes, spelling corrections, and minor API additions"
For the Bluetooth bits, Johan says:
"Here's the first bluetooth-next pull request for 3.19. The vast majority
of patches are for ieee802154 from Alexander Aring with various fixes
and cleanups. There are also several LE/SMP fixes as well as improved
support for handling LE devices that have lost their pairing information
(the patches from Alfonso). Jukka provides a couple of stability fixes
for 6lowpan and Szymon conformance fixes for RFCOMM. For the HCI drivers
we have one new USB ID for an Acer controller as well as a reset
handling fix for H5."
For the Atheros bits, Kalle says:
"Major changes are:
o ethtool support (Ben)
o print dev string prefix with debug hex buffers dump (Michal)
o debugfs file to read calibration data from the firmware verification
purposes (me)
o fix fw_stats debugfs file, now results are more reliable (Michal)
o firmware crash counters via debugfs (Ben&me)
o various tracing points to debug firmware (Rajkumar)
o make it possible to provide firmware calibration data via a file (me)
And we have quite a lot of smaller fixes and clean up."
For the iwlwifi bits, Emmanuel says:
"The big new thing here is netdetect which allows the
firmware to wake up the platform when a specific network
is detected. Along with that I have fixes for d3 operation.
The usual amount of rate scaling stuff - we now support STBC.
The other commit that stands out is Johannes's work on
devcoredump. He basically starts to use the standard
infrastructure he built."
Along with that are the usual sort of updates and such for ath9k,
brcmfmac, wil6210, and a handful of other bits here and there...
Please let me know if there are problems!
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This ways drivers like cxgb4 don't need to do ugly relative includes.
Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Tuning coalescing parameters on NIC can be really hard.
Servers can handle both bulk and RPC like traffic, with conflicting
goals : bulk flows want as big GRO packets as possible, RPC want minimal
latencies.
To reach big GRO packets on 10Gbe NIC, one can use :
ethtool -C eth0 rx-usecs 4 rx-frames 44
But this penalizes rpc sessions, with an increase of latencies, up to
50% in some cases, as NICs generally do not force an interrupt when
a packet with TCP Push flag is received.
Some NICs do not have an absolute timer, only a timer rearmed for every
incoming packet.
This patch uses a different strategy : Let GRO stack decides what do do,
based on traffic pattern.
Packets with Push flag wont be delayed.
Packets without Push flag might be held in GRO engine, if we keep
receiving data.
This new mechanism is off by default, and shall be enabled by setting
/sys/class/net/ethX/gro_flush_timeout to a value in nanosecond.
To fully enable this mechanism, drivers should use napi_complete_done()
instead of napi_complete().
Tested:
Ran 200 netperf TCP_STREAM from A to B (10Gbe mlx4 link, 8 RX queues)
Without this feature, we send back about 305,000 ACK per second.
GRO aggregation ratio is low (811/305 = 2.65 segments per GRO packet)
Setting a timer of 2000 nsec is enough to increase GRO packet sizes
and reduce number of ACK packets. (811/19.2 = 42)
Receiver performs less calls to upper stacks, less wakes up.
This also reduces cpu usage on the sender, as it receives less ACK
packets.
Note that reducing number of wakes up increases cpu efficiency, but can
decrease QPS, as applications wont have the chance to warmup cpu caches
doing a partial read of RPC requests/answers if they fit in one skb.
B:~# sar -n DEV 1 10 | grep eth0 | tail -1
Average: eth0 811269.80 305732.30 1199462.57 19705.72 0.00
0.00 0.50
B:~# echo 2000 >/sys/class/net/eth0/gro_flush_timeout
B:~# sar -n DEV 1 10 | grep eth0 | tail -1
Average: eth0 811577.30 19230.80 1199916.51 1239.80 0.00
0.00 0.50
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Babel uses rt_proto 42. Add to userspace visible header file.
Signed-off-by: Dave Taht <dave.taht@bufferbloat.net>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This new flag is useful for suppressing error logging while probing
for datapath features using flow commands. For backwards
compatibility reasons the commands are executed normally, but error
logging is suppressed.
Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
OVS vswitch has extended IPFIX exporter to export tunnel headers
to improve network visibility.
To export this information userspace needs to know egress tunnel
for given packet. By extending packet attributes datapath can
export egress tunnel info for given packet. So that userspace
can ask for egress tunnel info in userspace action. This
information is used to build IPFIX data for given flow.
Signed-off-by: Wenyu Zhang <wenyuz@vmware.com>
Acked-by: Romain Lenglet <rlenglet@vmware.com>
Acked-by: Ben Pfaff <blp@nicira.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
As NIC multicast filtering isn't perfect, and some platforms are
quite content to spew broadcasts, we should not trigger an event
for skb:kfree_skb when we do not have a match for such an incoming
datagram. We do though want to avoid sweeping the matter under the
rug entirely, so increment a suitable statistic.
This incorporates feedback from David L. Stevens, Karl Neiss and Eric
Dumazet.
V3 - use bool per David Miller
Signed-off-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The entries in the Kbuild files are incorrectly sorted.
Matters for aesthetics only.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that both macvtap and tun are using skb_copy_datagram_iter, we
can kill the abomination that is skb_copy_datagram_const_iovec.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds skb_copy_datagram_iter, which is identical to
skb_copy_datagram_iovec except that it operates on iov_iter
instead of iovec.
Eventually all users of skb_copy_datagram_iovec should switch
over to iov_iter and then we can remove skb_copy_datagram_iovec.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pravin B Shelar says:
====================
Open vSwitch
First two patches are related to OVS MPLS support. Rest of patches
are mostly refactoring and minor improvements to openvswitch.
v1-v2:
- Fix conflicts due to "gue: Remote checksum offload"
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently we need the IP6_TNL_F_CAP_XMIT capabiltiy to transmit
packets through an ipv6 tunnel. This capability is set when the
tunnel gets configured, based on the tunnel endpoint addresses.
On tunnels with wildcard tunnel endpoints, we need to do the
capabiltiy checking on a per packet basis like it is done in
the receive path.
This patch extends ip6_tnl_xmit_ctl() to take local and remote
addresses as parameters to allow for per packet capabiltiy
checking.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Should be the same as other IPv6 address fields.
Current master produces sparse warnings without this change.
Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Allow datapath to recognize and extract MPLS labels into flow keys
and execute actions which push, pop, and set labels on packets.
Based heavily on work by Leo Alterman, Ravi K, Isaku Yamahata and Joe Stringer.
Cc: Ravi K <rkerur@gmail.com>
Cc: Leo Alterman <lalterman@nicira.com>
Cc: Isaku Yamahata <yamahata@valinux.co.jp>
Cc: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Device can export MPLS GSO support in dev->mpls_features same way
it export vlan features in dev->vlan_features. So it is safe to
remove NETIF_F_GSO_MPLS redundant flag.
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
By default the arch_fast_hash hashing function pointers are initialized
to jhash(2). If during boot-up a CPU with SSE4.2 is detected they get
updated to the CRC32 ones. This dispatching scheme incurs a function
pointer lookup and indirect call for every hashing operation.
rhashtable as a user of arch_fast_hash e.g. stores pointers to hashing
functions in its structure, too, causing two indirect branches per
hashing operation.
Using alternative_call we can get away with one of those indirect branches.
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
if_bridge.h uses struct in6_addr ip6, but wasn't including the in6.h
header. Thomas Backlund originally sent a patch to do this, but this
revealed a redefinition issue: https://lkml.org/lkml/2013/1/13/116
The redefinition issue should have been fixed by the following Linux
commits:
ee262ad827 inet: defines IPPROTO_* needed for module alias generation
cfd280c912 net: sync some IP headers with glibc
and the following glibc commit:
6c82a2f8d7c8e21e39237225c819f182ae438db3 Coordinate IPv6 definitions for Linux and glibc
so actually include the header now.
Reported-by: Colin Guthrie <colin@mageia.org>
Reported-by: Christiaan Welvaart <cjw@daneel.dyndns.org>
Reported-by: Thomas Backlund <tmb@mageia.org>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Gregory Fong <gregory.0xf0@gmail.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is only used in net/ipv6/inet6_hashtables.c.
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This encapsulates all of the skb_copy_datagram_iovec() callers
with call argument signature "skb, offset, msghdr->msg_iov, length".
When we move to iov_iters in the networking, the iov_iter object will
sit in the msghdr.
Having a helper like this means there will be less places to touch
during that transformation.
Based upon descriptions and patch from Al Viro.
Signed-off-by: David S. Miller <davem@davemloft.net>
Add if_tunnel flag TUNNEL_ENCAP_FLAG_REMCSUM to configure
remote checksum offload on an IP tunnel. Add logic in gue_build_header
to insert remote checksum offload option.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Define a private flag for remote checksun offload as well as a length
for the option.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a new GSO type, SKB_GSO_TUNNEL_REMCSUM, which indicates remote
checksum offload being done (in this case inner checksum must not
be offloaded to the NIC).
Added logic in __skb_udp_tunnel_segment to handle remote checksum
offload case.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add functions and basic definitions for processing standard flags,
private flags, and control messages. This includes definitions
to compute length of optional fields corresponding to a set of flags.
Flag validation is in validate_gue_flags function. This checks for
unknown flags, and that length of optional fields is <= length
in guehdr hlen.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move fou_build_header out of ip_tunnel.c and into fou.c splitting
it up into fou_build_header, gue_build_header, and fou_build_udp.
This allows for other users for TX of FOU or GUE. Change ip_tunnel_encap
to call fou_build_header or gue_build_header based on the tunnel
encapsulation type. Similarly, added fou_encap_hlen and gue_encap_hlen
functions which are called by ip_encap_hlen. New net/fou.h has
prototypes and defines for this.
Added NET_FOU_IP_TUNNELS configuration. When this is set, IP tunnels
can use FOU/GUE and fou module is also selected.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
File descriptors are always closed on exit :-)
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>
following:
* large mac80211-hwsim changes from Ben, Jukka and a bit myself
* OCB/WAVE/11p support from Rostislav on behalf of the Czech Technical
University in Prague and Volkswagen Group Research
* minstrel VHT work from Karl
* more CSA work from Luca
* WMM admission control support in mac80211 (myself)
* various smaller fixes, spelling corrections, and minor API additions
-----BEGIN PGP SIGNATURE-----
iQIcBAABCAAGBQJUWMs/AAoJEDBSmw7B7bqrmBQQAIbfAe7wH1WifRtOnhw3zWQQ
K36+Edf3HlQ+EIkSs63QousRj2e7pGDOyhzMWLaqsmeTLteUtlGbr7qwiJO1QZdf
Ml2V5O2s+b8hUIClDBVQF2L6+GGUmRUdQqvDDhkN1guoxD/Nk8cNtsRkSdiXWJWy
R48NzvYDflBhc8uqPtR8jDb10eM3c00YP9HB+w9hYAfizD+FRue7UNp4MQIqwp9V
HdKRT6L2n/6QA+Mzse0rMDes5qI7nIUNgj+hjqgJSnhITPMgGR5j/pitnVHrr81M
ngOipBFG3svsQrwZh8nM4Llp0cM4Gs+GlgCieu9+TJpr2sY00Z3kYcp0pxtDoSxz
Wblqz9n/bnW9mrkEfl12XqwwT5vguchwHoZ9cXhejDxSawWXoTRx20uW4ahO8ArA
kWwwjTBVsQ5WMCtOBiqggzNKghwCc2ILmcZnjGdg9aNXcWsmQ4vyeCfG2QxBz/UB
Grv/f9NSy6mzKQ34yv+lyR7rFZ8XcT03EVAnZSYz8X0ZZGxwtFupRp1RrBh1KPtD
TJoe6Q71FfHKYRJ2xgygYkQFo+r9d0BKBeerq+Vu2hBeaqyi4aUwSj7d1sUaaq6N
tL8fmAUqFjVOOUFeH1g07Xke5QD+yrEC7sJKkeRMfcRGB+dEa+2m3I5p4WDz9bWM
AEvFSsYr/I9KI4d1huXD
=6GIj
-----END PGP SIGNATURE-----
Merge tag 'mac80211-next-for-john-2014-11-04' of git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211-next
Johannes Berg <johannes@sipsolutions.net> says:
"This relatively large batch of changes is comprised of the
following:
* large mac80211-hwsim changes from Ben, Jukka and a bit myself
* OCB/WAVE/11p support from Rostislav on behalf of the Czech Technical
University in Prague and Volkswagen Group Research
* minstrel VHT work from Karl
* more CSA work from Luca
* WMM admission control support in mac80211 (myself)
* various smaller fixes, spelling corrections, and minor API additions"
Conflicts:
drivers/net/wireless/ath/wil6210/cfg80211.c
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This patch allows to set ECN on a per-route basis in case the sysctl
tcp_ecn is not set to 1. In other words, when ECN is set for specific
routes, it provides a tcp_ecn=1 behaviour for that route while the rest
of the stack acts according to the global settings.
One can use 'ip route change dev $dev $net features ecn' to toggle this.
Having a more fine-grained per-route setting can be beneficial for various
reasons, for example, 1) within data centers, or 2) local ISPs may deploy
ECN support for their own video/streaming services [1], etc.
There was a recent measurement study/paper [2] which scanned the Alexa's
publicly available top million websites list from a vantage point in US,
Europe and Asia:
Half of the Alexa list will now happily use ECN (tcp_ecn=2, most likely
blamed to commit 255cac91c3 ("tcp: extend ECN sysctl to allow server-side
only ECN") ;)); the break in connectivity on-path was found is about
1 in 10,000 cases. Timeouts rather than receiving back RSTs were much
more common in the negotiation phase (and mostly seen in the Alexa
middle band, ranks around 50k-150k): from 12-thousand hosts on which
there _may_ be ECN-linked connection failures, only 79 failed with RST
when _not_ failing with RST when ECN is not requested.
It's unclear though, how much equipment in the wild actually marks CE
when buffers start to fill up.
We thought about a fallback to non-ECN for retransmitted SYNs as another
global option (which could perhaps one day be made default), but as Eric
points out, there's much more work needed to detect broken middleboxes.
Two examples Eric mentioned are buggy firewalls that accept only a single
SYN per flow, and middleboxes that successfully let an ECN flow establish,
but later mark CE for all packets (so cwnd converges to 1).
[1] http://www.ietf.org/proceedings/89/slides/slides-89-tsvarea-1.pdf, p.15
[2] http://ecn.ethz.ch/
Joint work with Daniel Borkmann.
Reference: http://thread.gmane.org/gmane.linux.network/335797
Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
The function cookie_check_timestamp(), both called from IPv4/6 context,
is being used to decode the echoed timestamp from the SYN/ACK into TCP
options used for follow-up communication with the peer.
We can remove ECN handling from that function, split it into a separate
one, and simply rename the original function into cookie_decode_options().
cookie_decode_options() just fills in tcp_option struct based on the
echoed timestamp received from the peer. Anything that fails in this
function will actually discard the request socket.
While this is the natural place for decoding options such as ECN which
commit 172d69e63c ("syncookies: add support for ECN") added, we argue
that in particular for ECN handling, it can be checked at a later point
in time as the request sock would actually not need to be dropped from
this, but just ECN support turned off.
Therefore, we split this functionality into cookie_ecn_ok(), which tells
us if the timestamp indicates ECN support AND the tcp_ecn sysctl is enabled.
This prepares for per-route ECN support: just looking at the tcp_ecn sysctl
won't be enough anymore at that point; if the timestamp indicates ECN
and sysctl tcp_ecn == 0, we will also need to check the ECN dst metric.
This would mean adding a route lookup to cookie_check_timestamp(), which
we definitely want to avoid. As we already do a route lookup at a later
point in cookie_{v4,v6}_check(), we can simply make use of that as well
for the new cookie_ecn_ok() function w/o any additional cost.
Joint work with Daniel Borkmann.
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Drivers might want to know also when mac80211 has
completed reconfiguring after resume (e.g. in order
to know when frames can be passed to mac80211).
Rename restart_complete() to a more-generic reconfig_complete(),
and add a new enum to indicate the reconfiguration type.
Update the current users with the new prototype.
Signed-off-by: Eliad Peller <eliadx.peller@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This patch adds 802.11p OCB (Outside the Context of a BSS) mode
support.
When communicating in OCB mode a mandatory wildcard BSSID
(48 '1' bits) is used.
The EDCA parameters handling function was changed to support
802.11p specific values.
The insertion of a newly discovered STAs is done in the similar way
as in the IBSS mode -- through the deferred insertion.
The OCB mode uses a periodic 'housekeeping task' for expiration of
disconnected STAs (in the similar manner as in the MESH mode).
New Kconfig option for verbose OCB debugging outputs is added.
Signed-off-by: Rostislav Lisovy <rostislav.lisovy@fel.cvut.cz>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This patch adds new iface type (NL80211_IFTYPE_OCB) representing
the OCB (Outside the Context of a BSS) mode.
When establishing a connection to the network a cfg80211_join_ocb
function is called (particular nl80211_command is added as well).
A mandatory parameters during the ocb_join operation are 'center
frequency' and 'channel width (5/10 MHz)'.
Changes done in mac80211 are minimal possible required to avoid
many warnings (warning: enumeration value 'NL80211_IFTYPE_OCB'
not handled in switch) during compilation. Full functionality
(where needed) is added in the following patch.
Signed-off-by: Rostislav Lisovy <rostislav.lisovy@fel.cvut.cz>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The configured tx power is often limited by hardware capabilities,
channel settings, antenna configuration, etc.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
[fix tracing compilation]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Herbert Xu