While testing how linux behaves on SYNFLOOD attack on multiqueue device
(ixgbe), I found that SYNACK messages were dropped at Qdisc level
because we send them all on a single queue.
Obvious choice is to reflect incoming SYN packet @queue_mapping to
SYNACK packet.
Under stress, my machine could only send 25.000 SYNACK per second (for
200.000 incoming SYN per second). NIC : ixgbe with 16 rx/tx queues.
After patch, not a single SYNACK is dropped.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Hans Schillstrom <hans.schillstrom@ericsson.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull networking changes from David S. Miller:
1) Fix IPSEC header length calculation for transport mode in ESP. The
issue is whether to do the calculation before or after alignment.
Fix from Benjamin Poirier.
2) Fix regression in IPV6 IPSEC fragment length calculations, from Gao
Feng. This is another transport vs tunnel mode issue.
3) Handle AF_UNSPEC connect()s properly in L2TP to avoid OOPSes. Fix
from James Chapman.
4) Fix USB ASIX driver's reception of full sized VLAN packets, from
Eric Dumazet.
5) Allow drop monitor (and, more generically, all generic netlink
protocols) to be automatically loaded as a module. From Neil
Horman.
Fix up trivial conflict in Documentation/feature-removal-schedule.txt
due to new entries added next to each other at the end. As usual.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (38 commits)
net/smsc911x: Repair broken failure paths
virtio-net: remove useless disable on freeze
netdevice: Update netif_dbg for CONFIG_DYNAMIC_DEBUG
drop_monitor: Add module alias to enable automatic module loading
genetlink: Build a generic netlink family module alias
net: add MODULE_ALIAS_NET_PF_PROTO_NAME
r6040: Do a Proper deinit at errorpath and also when driver unloads (calling r6040_remove_one)
r6040: disable pci device if the subsequent calls (after pci_enable_device) fails
skb: avoid unnecessary reallocations in __skb_cow
net: sh_eth: fix the rxdesc pointer when rx descriptor empty happens
asix: allow full size 8021Q frames to be received
rds_rdma: don't assume infiniband device is PCI
l2tp: fix oops in L2TP IP sockets for connect() AF_UNSPEC case
mac80211: fix ADDBA declined after suspend with wowlan
wlcore: fix undefined symbols when CONFIG_PM is not defined
mac80211: fix flag check for QoS NOACK frames
ath9k_hw: apply internal regulator settings on AR933x
ath9k_hw: update AR933x initvals to fix issues with high power devices
ath9k: fix a use-after-free-bug when ath_tx_setup_buffer() fails
ath9k: stop rx dma before stopping tx
...
We call the destroy function when a cgroup starts to be removed, such as
by a rmdir event.
However, because of our reference counters, some objects are still
inflight. Right now, we are decrementing the static_keys at destroy()
time, meaning that if we get rid of the last static_key reference, some
objects will still have charges, but the code to properly uncharge them
won't be run.
This becomes a problem specially if it is ever enabled again, because now
new charges will be added to the staled charges making keeping it pretty
much impossible.
We just need to be careful with the static branch activation: since there
is no particular preferred order of their activation, we need to make sure
that we only start using it after all call sites are active. This is
achieved by having a per-memcg flag that is only updated after
static_key_slow_inc() returns. At this time, we are sure all sites are
active.
This is made per-memcg, not global, for a reason: it also has the effect
of making socket accounting more consistent. The first memcg to be
limited will trigger static_key() activation, therefore, accounting. But
all the others will then be accounted no matter what. After this patch,
only limited memcgs will have its sockets accounted.
[akpm@linux-foundation.org: move enum sock_flag_bits into sock.h,
document enum sock_flag_bits,
convert memcg_proto_active() and memcg_proto_activated() to test_bit(),
redo tcp_update_limit() comment to 80 cols]
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Acked-by: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Corrects the function that determines the esp payload size. The calculations
done in esp{4,6}_get_mtu() lead to overlength frames in transport mode for
certain mtu values and suboptimal frames for others.
According to what is done, mainly in esp{,6}_output() and tcp_mtu_to_mss(),
net_header_len must be taken into account before doing the alignment
calculation.
Signed-off-by: Benjamin Poirier <bpoirier@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull more networking updates from David Miller:
"Ok, everything from here on out will be bug fixes."
1) One final sync of wireless and bluetooth stuff from John Linville.
These changes have all been in his tree for more than a week, and
therefore have had the necessary -next exposure. John was just away
on a trip and didn't have a change to send the pull request until a
day or two ago.
2) Put back some defines in user exposed header file areas that were
removed during the tokenring purge. From Stephen Hemminger and Paul
Gortmaker.
3) A bug fix for UDP hash table allocation got lost in the pile due to
one of those "you got it.. no I've got it.." situations. :-)
From Tim Bird.
4) SKB coalescing in TCP needs to have stricter checks, otherwise we'll
try to coalesce overlapping frags and crash. Fix from Eric Dumazet.
5) RCU routing table lookups can race with free_fib_info(), causing
crashes when we deref the device pointers in the route. Fix by
releasing the net device in the RCU callback. From Yanmin Zhang.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (293 commits)
tcp: take care of overlaps in tcp_try_coalesce()
ipv4: fix the rcu race between free_fib_info and ip_route_output_slow
mm: add a low limit to alloc_large_system_hash
ipx: restore token ring define to include/linux/ipx.h
if: restore token ring ARP type to header
xen: do not disable netfront in dom0
phy/micrel: Fix ID of KSZ9021
mISDN: Add X-Tensions USB ISDN TA XC-525
gianfar:don't add FCB length to hard_header_len
Bluetooth: Report proper error number in disconnection
Bluetooth: Create flags for bt_sk()
Bluetooth: report the right security level in getsockopt
Bluetooth: Lock the L2CAP channel when sending
Bluetooth: Restore locking semantics when looking up L2CAP channels
Bluetooth: Fix a redundant and problematic incoming MTU check
Bluetooth: Add support for Foxconn/Hon Hai AR5BBU22 0489:E03C
Bluetooth: Fix EIR data generation for mgmt_device_found
Bluetooth: Fix Inquiry with RSSI event mask
Bluetooth: improve readability of l2cap_seq_list code
Bluetooth: Fix skb length calculation
...
Sergio Correia reported following warning :
WARNING: at net/ipv4/tcp.c:1301 tcp_cleanup_rbuf+0x4f/0x110()
WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
"cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
It appears TCP coalescing, and more specifically commit b081f85c29
(net: implement tcp coalescing in tcp_queue_rcv()) should take care of
possible segment overlaps in receive queue. This was properly done in
the case of out_or_order_queue by the caller.
For example, segment at tail of queue have sequence 1000-2000, and we
add a segment with sequence 1500-2500.
This can happen in case of retransmits.
In this case, just don't do the coalescing.
Reported-by: Sergio Correia <lists@uece.net>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Sergio Correia <lists@uece.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
We hit a kernel OOPS.
<3>[23898.789643] BUG: sleeping function called from invalid context at
/data/buildbot/workdir/ics/hardware/intel/linux-2.6/arch/x86/mm/fault.c:1103
<3>[23898.862215] in_atomic(): 0, irqs_disabled(): 0, pid: 10526, name:
Thread-6683
<4>[23898.967805] HSU serial 0000:00:05.1: 0000:00:05.2:HSU serial prevented me
to suspend...
<4>[23899.258526] Pid: 10526, comm: Thread-6683 Tainted: G W
3.0.8-137685-ge7742f9 #1
<4>[23899.357404] HSU serial 0000:00:05.1: 0000:00:05.2:HSU serial prevented me
to suspend...
<4>[23899.904225] Call Trace:
<4>[23899.989209] [<c1227f50>] ? pgtable_bad+0x130/0x130
<4>[23900.000416] [<c1238c2a>] __might_sleep+0x10a/0x110
<4>[23900.007357] [<c1228021>] do_page_fault+0xd1/0x3c0
<4>[23900.013764] [<c18e9ba9>] ? restore_all+0xf/0xf
<4>[23900.024024] [<c17c007b>] ? napi_complete+0x8b/0x690
<4>[23900.029297] [<c1227f50>] ? pgtable_bad+0x130/0x130
<4>[23900.123739] [<c1227f50>] ? pgtable_bad+0x130/0x130
<4>[23900.128955] [<c18ea0c3>] error_code+0x5f/0x64
<4>[23900.133466] [<c1227f50>] ? pgtable_bad+0x130/0x130
<4>[23900.138450] [<c17f6298>] ? __ip_route_output_key+0x698/0x7c0
<4>[23900.144312] [<c17f5f8d>] ? __ip_route_output_key+0x38d/0x7c0
<4>[23900.150730] [<c17f63df>] ip_route_output_flow+0x1f/0x60
<4>[23900.156261] [<c181de58>] ip4_datagram_connect+0x188/0x2b0
<4>[23900.161960] [<c18e981f>] ? _raw_spin_unlock_bh+0x1f/0x30
<4>[23900.167834] [<c18298d6>] inet_dgram_connect+0x36/0x80
<4>[23900.173224] [<c14f9e88>] ? _copy_from_user+0x48/0x140
<4>[23900.178817] [<c17ab9da>] sys_connect+0x9a/0xd0
<4>[23900.183538] [<c132e93c>] ? alloc_file+0xdc/0x240
<4>[23900.189111] [<c123925d>] ? sub_preempt_count+0x3d/0x50
Function free_fib_info resets nexthop_nh->nh_dev to NULL before releasing
fi. Other cpu might be accessing fi. Fixing it by delaying the releasing.
With the patch, we ran MTBF testing on Android mobile for 12 hours
and didn't trigger the issue.
Thank Eric for very detailed review/checking the issue.
Signed-off-by: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Signed-off-by: Kun Jiang <kunx.jiang@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
UDP stack needs a minimum hash size value for proper operation and also
uses alloc_large_system_hash() for proper NUMA distribution of its hash
tables and automatic sizing depending on available system memory.
On some low memory situations, udp_table_init() must ignore the
alloc_large_system_hash() result and reallocs a bigger memory area.
As we cannot easily free old hash table, we leak it and kmemleak can
issue a warning.
This patch adds a low limit parameter to alloc_large_system_hash() to
solve this problem.
We then specify UDP_HTABLE_SIZE_MIN for UDP/UDPLite hash table
allocation.
Reported-by: Mark Asselstine <mark.asselstine@windriver.com>
Reported-by: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull user namespace enhancements from Eric Biederman:
"This is a course correction for the user namespace, so that we can
reach an inexpensive, maintainable, and reasonably complete
implementation.
Highlights:
- Config guards make it impossible to enable the user namespace and
code that has not been converted to be user namespace safe.
- Use of the new kuid_t type ensures the if you somehow get past the
config guards the kernel will encounter type errors if you enable
user namespaces and attempt to compile in code whose permission
checks have not been updated to be user namespace safe.
- All uids from child user namespaces are mapped into the initial
user namespace before they are processed. Removing the need to add
an additional check to see if the user namespace of the compared
uids remains the same.
- With the user namespaces compiled out the performance is as good or
better than it is today.
- For most operations absolutely nothing changes performance or
operationally with the user namespace enabled.
- The worst case performance I could come up with was timing 1
billion cache cold stat operations with the user namespace code
enabled. This went from 156s to 164s on my laptop (or 156ns to
164ns per stat operation).
- (uid_t)-1 and (gid_t)-1 are reserved as an internal error value.
Most uid/gid setting system calls treat these value specially
anyway so attempting to use -1 as a uid would likely cause
entertaining failures in userspace.
- If setuid is called with a uid that can not be mapped setuid fails.
I have looked at sendmail, login, ssh and every other program I
could think of that would call setuid and they all check for and
handle the case where setuid fails.
- If stat or a similar system call is called from a context in which
we can not map a uid we lie and return overflowuid. The LFS
experience suggests not lying and returning an error code might be
better, but the historical precedent with uids is different and I
can not think of anything that would break by lying about a uid we
can't map.
- Capabilities are localized to the current user namespace making it
safe to give the initial user in a user namespace all capabilities.
My git tree covers all of the modifications needed to convert the core
kernel and enough changes to make a system bootable to runlevel 1."
Fix up trivial conflicts due to nearby independent changes in fs/stat.c
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (46 commits)
userns: Silence silly gcc warning.
cred: use correct cred accessor with regards to rcu read lock
userns: Convert the move_pages, and migrate_pages permission checks to use uid_eq
userns: Convert cgroup permission checks to use uid_eq
userns: Convert tmpfs to use kuid and kgid where appropriate
userns: Convert sysfs to use kgid/kuid where appropriate
userns: Convert sysctl permission checks to use kuid and kgids.
userns: Convert proc to use kuid/kgid where appropriate
userns: Convert ext4 to user kuid/kgid where appropriate
userns: Convert ext3 to use kuid/kgid where appropriate
userns: Convert ext2 to use kuid/kgid where appropriate.
userns: Convert devpts to use kuid/kgid where appropriate
userns: Convert binary formats to use kuid/kgid where appropriate
userns: Add negative depends on entries to avoid building code that is userns unsafe
userns: signal remove unnecessary map_cred_ns
userns: Teach inode_capable to understand inodes whose uids map to other namespaces.
userns: Fail exec for suid and sgid binaries with ids outside our user namespace.
userns: Convert stat to return values mapped from kuids and kgids
userns: Convert user specfied uids and gids in chown into kuids and kgid
userns: Use uid_eq gid_eq helpers when comparing kuids and kgids in the vfs
...
Pull cgroup updates from Tejun Heo:
"cgroup file type addition / removal is updated so that file types are
added and removed instead of individual files so that dynamic file
type addition / removal can be implemented by cgroup and used by
controllers. blkio controller changes which will come through block
tree are dependent on this. Other changes include res_counter cleanup
and disallowing kthread / PF_THREAD_BOUND threads to be attached to
non-root cgroups.
There's a reported bug with the file type addition / removal handling
which can lead to oops on cgroup umount. The issue is being looked
into. It shouldn't cause problems for most setups and isn't a
security concern."
Fix up trivial conflict in Documentation/feature-removal-schedule.txt
* 'for-3.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (21 commits)
res_counter: Account max_usage when calling res_counter_charge_nofail()
res_counter: Merge res_counter_charge and res_counter_charge_nofail
cgroups: disallow attaching kthreadd or PF_THREAD_BOUND threads
cgroup: remove cgroup_subsys->populate()
cgroup: get rid of populate for memcg
cgroup: pass struct mem_cgroup instead of struct cgroup to socket memcg
cgroup: make css->refcnt clearing on cgroup removal optional
cgroup: use negative bias on css->refcnt to block css_tryget()
cgroup: implement cgroup_rm_cftypes()
cgroup: introduce struct cfent
cgroup: relocate __d_cgrp() and __d_cft()
cgroup: remove cgroup_add_file[s]()
cgroup: convert memcg controller to the new cftype interface
memcg: always create memsw files if CONFIG_CGROUP_MEM_RES_CTLR_SWAP
cgroup: convert all non-memcg controllers to the new cftype interface
cgroup: relocate cftype and cgroup_subsys definitions in controllers
cgroup: merge cft_release_agent cftype array into the base files array
cgroup: implement cgroup_add_cftypes() and friends
cgroup: build list of all cgroups under a given cgroupfs_root
cgroup: move cgroup_clear_directory() call out of cgroup_populate_dir()
...
Replace simple_strtoul with kstrtoul in three similar occurrences, all setup
handlers:
* route.c: set_rhash_entries
* tcp.c: set_thash_entries
* udp.c: set_uhash_entries
Also check if the conversion failed.
Signed-off-by: Eldad Zack <eldad@fogrefinery.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The __setup macro should follow the corresponding setup handler.
Signed-off-by: Eldad Zack <eldad@fogrefinery.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ip_frag_reasm() can use skb_try_coalesce() to build optimized skb,
reducing memory used by them (truesize), and reducing number of cache
line misses and overhead for the consumer.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move tcp_try_coalesce() protocol independent part to
skb_try_coalesce().
skb_try_coalesce() can be used in IPv4 defrag and IPv6 reassembly,
to build optimized skbs (less sk_buff, and possibly less 'headers')
skb_try_coalesce() is zero copy, unless the copy can fit in destination
header (its a rare case)
kfree_skb_partial() is also moved to net/core/skbuff.c and exported,
because IPv6 will need it in patch (ipv6: use skb coalescing in
reassembly).
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
- match() method returns a boolean
- return (A && B && C && D) -> return A && B && C && D
- fix indentation
Signed-off-by: Eric Dumazet <edumazet@google.com>
Since recent changes on TCP splicing (starting with commits 2f533844
"tcp: allow splice() to build full TSO packets" and 35f9c09f "tcp:
tcp_sendpages() should call tcp_push() once"), I started seeing
massive stalls when forwarding traffic between two sockets using
splice() when pipe buffers were larger than socket buffers.
Latest changes (net: netdev_alloc_skb() use build_skb()) made the
problem even more apparent.
The reason seems to be that if do_tcp_sendpages() fails on out of memory
condition without being able to send at least one byte, tcp_push() is not
called and the buffers cannot be flushed.
After applying the attached patch, I cannot reproduce the stalls at all
and the data rate it perfectly stable and steady under any condition
which previously caused the problem to be permanent.
The issue seems to have been there since before the kernel migrated to
git, which makes me think that the stalls I occasionally experienced
with tux during stress-tests years ago were probably related to the
same issue.
This issue was first encountered on 3.0.31 and 3.2.17, so please backport
to -stable.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Acked-by: Eric Dumazet <edumazet@google.com>
Cc: <stable@vger.kernel.org>
bool conversions where possible.
__inline__ -> inline
space cleanups
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
bool/const conversions where possible
__inline__ -> inline
space cleanups
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use the current debugging style and enable dynamic_debug.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We are going to delete the Token ring support. This removes any
special processing in the core networking for token ring, (aside
from net/tr.c itself), leaving the drivers and remaining tokenring
support present but inert.
The mass removal of the drivers and net/tr.c will be in a separate
commit, so that the history of these files that we still care
about won't have the giant deletion tied into their history.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Standardize the net core ratelimited logging functions.
Coalesce formats, align arguments.
Change a printk then vprintk sequence to use printf extension %pV.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
By making this a standalone config option (auto-selected as needed),
selecting CRYPTO from here rather than from XFRM (which is boolean)
allows the core crypto code to become a module again even when XFRM=y.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As proposed by Eric, make the tcp_input.o thinner.
add/remove: 1/1 grow/shrink: 1/4 up/down: 868/-1329 (-461)
function old new delta
tcp_try_rmem_schedule - 864 +864
tcp_ack 4811 4815 +4
tcp_validate_incoming 817 815 -2
tcp_collapse 860 858 -2
tcp_send_rcvq 555 353 -202
tcp_data_queue 3435 3033 -402
tcp_prune_queue 721 - -721
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As noted by Eric, no checks are performed on the data size we're
putting in the read queue during repair. Thus, validate the given
data size with the common rmem management routine.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It actually works on the input queue and will use its read mem
routines, thus it's better to have in in the tcp_input.c file.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Due to RCU lookups and RCU based release, fib_info objects can
be found during lookup which have fi->fib_dead set.
We must ignore these entries, otherwise we risk dereferencing
the parts of the entry which are being torn down.
Reported-by: Yevgen Pronenko <yevgen.pronenko@sonymobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch removes ip_queue support which was marked as obsolete
years ago. The nfnetlink_queue modules provides more advanced
user-space packet queueing mechanism.
This patch also removes capability code included in SELinux that
refers to ip_queue. Otherwise, we break compilation.
Several warning has been sent regarding this to the mailing list
in the past month without anyone rising the hand to stop this
with some strong argument.
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>
Until now, struct mreq has not been recognized and it was worked with
as with struct in_addr. That means imr_multiaddr was copied to
imr_address. So do recognize struct mreq here and copy that correctly.
Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It appears some networks play bad games with the two bits reserved for
ECN. This can trigger false congestion notifications and very slow
transferts.
Since RFC 3168 (6.1.1) forbids SYN packets to carry CT bits, we can
disable TCP ECN negociation if it happens we receive mangled CT bits in
the SYN packet.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Perry Lorier <perryl@google.com>
Cc: Matt Mathis <mattmathis@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Wilmer van der Gaast <wilmer@google.com>
Cc: Ankur Jain <jankur@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Dave Täht <dave.taht@bufferbloat.net>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds support for a skb_head_is_locked helper function. It is
meant to be used any time we are considering transferring the head from
skb->head to a paged frag. If the head is locked it means we cannot remove
the head from the skb so it must be copied or we must take the skb as a
whole.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As a first step to converting struct cred to be all kuid_t and kgid_t
values convert the group values stored in group_info to always be
kgid_t values. Unless user namespaces are used this change should
have no effect.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This change cleans up the last bits of tcp_try_coalesce so that we only
need one goto which jumps to the end of the function. The idea is to make
the code more readable by putting things in a linear order so that we start
execution at the top of the function, and end it at the bottom.
I also made a slight tweak to the code for handling frags when we are a
clone. Instead of making it an if (clone) loop else nr_frags = 0 I changed
the logic so that if (!clone) we just set the number of frags to 0 which
disables the for loop anyway.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This change reorders the code related to the use of an skb->head_frag so it
is placed before we check the rest of the frags. This allows the code to
read more linearly instead of like some sort of loop.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch addresses several issues in the way we were tracking the
truesize in tcp_try_coalesce.
First it was using ksize which prevents us from having a 0 sized head frag
and getting a usable result. To resolve that this patch uses the end
pointer which is set based off either ksize, or the frag_size supplied in
build_skb. This allows us to compute the original truesize of the entire
buffer and remove that value leaving us with just what was added as pages.
The second issue was the use of skb->len if there is a mergeable head frag.
We should only need to remove the size of an data aligned sk_buff from our
current skb->truesize to compute the delta for a buffer with a reused head.
By using skb->len the value of truesize was being artificially reduced
which means that head frags could use more memory than buffers using
standard allocations.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This change is meant ot prevent stealing the skb->head to use as a page in
the event that the skb->head was cloned. This allows the other clones to
track each other via shinfo->dataref.
Without this we break down to two methods for tracking the reference count,
one being dataref, the other being the page count. As a result it becomes
difficult to track how many references there are to skb->head.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Extend tcp coalescing implementing it from tcp_queue_rcv(), the main
receiver function when application is not blocked in recvmsg().
Function tcp_queue_rcv() is moved a bit to allow its call from
tcp_data_queue()
This gives good results especially if GRO could not kick, and if skb
head is a fragment.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Before stealing fragments or skb head, we must make sure skbs are not
cloned.
Alexander was worried about destination skb being cloned : In bridge
setups, a driver could be fooled if skb->data_len would not match skb
nr_frags.
If source skb is cloned, we must take references on pages instead.
Bug happened using tcpdump (if not using mmap())
Introduce kfree_skb_partial() helper to cleanup code.
Reported-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
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>
Implementing the advanced early retransmit (sysctl_tcp_early_retrans==2).
Delays the fast retransmit by an interval of RTT/4. We borrow the
RTO timer to implement the delay. If we receive another ACK or send
a new packet, the timer is cancelled and restored to original RTO
value offset by time elapsed. When the delayed-ER timer fires,
we enter fast recovery and perform fast retransmit.
Signed-off-by: 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>
This a prepartion patch that refactors the code to enter recovery
into a new function tcp_enter_recovery(). It's needed to implement
the delayed fast retransmit in ER.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
TCP coalesce can check if skb to be merged has its skb->head mapped to a
page fragment, instead of a kmalloc() area.
We had to disable coalescing in this case, for performance reasons.
We 'upgrade' skb->head as a fragment in itself.
This reduces number of cache misses when user makes its copies, since a
less sk_buff are fetched.
This makes receive and ofo queues shorter and thus reduce cache line
misses in TCP stack.
This is a followup of patch "net: allow skb->head to be a page fragment"
Tested with tg3 nic, with GRO on or off. We can see "TCPRcvCoalesce"
counter being incremented.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Maciej Żenczykowski <maze@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Cc: Matt Carlson <mcarlson@broadcom.com>
Cc: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When the cwnd reduction is done, ssthresh may be infinite
if TCP enters CWR via ECN or F-RTO. If cwnd is not undone, i.e.,
undo_marker is set, tcp_complete_cwr() falsely set cwnd to the
infinite ssthresh value. The correct operation is to keep cwnd
intact because it has been updated in ECN or F-RTO.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Clean up a reference to jiffies in tcp_rcv_rtt_measure() that should
instead reference tcp_time_stamp. Since the result of the subtraction
is passed into a function taking u32, this should not change any
behavior (and indeed the generated assembly does not change on
x86_64). However, it seems worth cleaning this up for consistency and
clarity (and perhaps to avoid bugs if this is copied and pasted
somewhere else).
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Quoting Tore Anderson from :
https://bugzilla.kernel.org/show_bug.cgi?id=42572
When RTAX_FEATURE_ALLFRAG is set on a route, the effective TCP segment
size does not take into account the size of the IPv6 Fragmentation
header that needs to be included in outbound packets, causing every
transmitted TCP segment to be fragmented across two IPv6 packets, the
latter of which will only contain 8 bytes of actual payload.
RTAX_FEATURE_ALLFRAG is typically set on a route in response to
receving a ICMPv6 Packet Too Big message indicating a Path MTU of less
than 1280 bytes. 1280 bytes is the minimum IPv6 MTU, however ICMPv6
PTBs with MTU < 1280 are still valid, in particular when an IPv6
packet is sent to an IPv4 destination through a stateless translator.
Any ICMPv4 Need To Fragment packets originated from the IPv4 part of
the path will be translated to ICMPv6 PTB which may then indicate an
MTU of less than 1280.
The Linux kernel refuses to reduce the effective MTU to anything below
1280 bytes, instead it sets it to exactly 1280 bytes, and
RTAX_FEATURE_ALLFRAG is also set. However, the TCP segment size appears
to be set to 1240 bytes (1280 Path MTU - 40 bytes of IPv6 header),
instead of 1232 (additionally taking into account the 8 bytes required
by the IPv6 Fragmentation extension header).
This in turn results in rather inefficient transmission, as every
transmitted TCP segment now is split in two fragments containing
1232+8 bytes of payload.
After this patch, all the outgoing packets that includes a
Fragmentation header all are "atomic" or "non-fragmented" fragments,
i.e., they both have Offset=0 and More Fragments=0.
With help from David S. Miller
Reported-by: Tore Anderson <tore@fud.no>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Maciej Żenczykowski <maze@google.com>
Cc: Tom Herbert <therbert@google.com>
Tested-by: Tore Anderson <tore@fud.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
