unify tcp flag macros: TCPHDR_FIN, TCPHDR_SYN, TCPHDR_RST, TCPHDR_PSH,
TCPHDR_ACK, TCPHDR_URG, TCPHDR_ECE and TCPHDR_CWR. TCBCB_FLAG_* are replaced
with the corresponding TCPHDR_*.
Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
----
 include/net/tcp.h                      |   24 ++++++-------
 net/ipv4/tcp.c                         |    8 ++--
 net/ipv4/tcp_input.c                   |    2 -
 net/ipv4/tcp_output.c                  |   59 ++++++++++++++++-----------------
 net/netfilter/nf_conntrack_proto_tcp.c |   32 ++++++-----------
 net/netfilter/xt_TCPMSS.c              |    4 --
 6 files changed, 58 insertions(+), 71 deletions(-)
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Try to reduce cache line contentions in peer management, to reduce IP
defragmentation overhead.

- peer_fake_node is marked 'const' to make sure its not modified.
  (tested with CONFIG_DEBUG_RODATA=y)

- Group variables in two structures to reduce number of dirtied cache
lines. One named "peers" for avl tree root, its number of entries, and
associated lock. (candidate for RCU conversion)

- A second one named "unused_peers" for unused list and its lock

- Add a !list_empty() test in unlink_from_unused() to avoid taking lock
when entry is not unused.

- Use atomic_dec_and_lock() in inet_putpeer() to avoid taking lock in
some cases.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

remove useless union keyword in rtable, rt6_info and dn_route.

Since there is only one member in a union, the union keyword isn't useful.
Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit 66018506 (ip: Router Alert RCU conversion) introduced RCU
lookups to ip_call_ra_chain(). It missed proper deinit phase :
When ip_ra_control() deletes an ip_ra_chain, it should make sure
ip_call_ra_chain() users can not start to use socket during the rcu
grace period. It should also delay the sock_put() after the grace
period, or we risk a premature socket freeing and corruptions, as
raw sockets are not rcu protected yet.

This delay avoids using expensive atomic_inc_not_zero() in
ip_call_ra_chain().
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- rcu_read_lock() already held by caller
- use __in_dev_get_rcu() instead of in_dev_get() / in_dev_put()
- remove goto out;
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

in_dev_get() -> __in_dev_get_rcu() in a rcu protected function.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

in_dev_get() -> __in_dev_get_rcu() in a rcu protected function.

[ Fix build with CONFIG_IP_ROUTE_VERBOSE disabled. -DaveM ]
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

in_dev_get() -> __in_dev_get_rcu() in a rcu protected function.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Straightforward conversion to RCU.

One rwlock becomes a spinlock, and is static.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ipmr_rules_exit() and ip6mr_rules_exit() free a list of items, but
forget to properly remove these items from list. List head is not
changed and still points to freed memory.

This can trigger a fault later when icmpv6_sk_exit() is called.

Fix is to either reinit list, or use list_del() to properly remove items
from list before freeing them.

bugzilla report : https://bugzilla.kernel.org/show_bug.cgi?id=16120

Introduced by commit d1db275d (ipv6: ip6mr: support multiple
tables) and commit f0ad0860 (ipv4: ipmr: support multiple tables)
Reported-by: NAlex Zhavnerchik <alex.vizor@gmail.com>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
CC: Patrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Avoid two atomic ops per raw_send_hdrinc() call

Avoid two atomic ops per raw6_send_hdrinc() call
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch address a serious performance issue in reading the
TCP sockets table (/proc/net/tcp).

Reading the full table is done by a number of sequential read
operations.  At each read operation, a seek is done to find the
last socket that was previously read.  This seek operation requires
that the sockets in the table need to be counted up to the current
file position, and to count each of these requires taking a lock for
each non-empty bucket.  The whole algorithm is O(n^2).

The fix is to cache the last bucket value, offset within the bucket,
and the file position returned by the last read operation.   On the
next sequential read, the bucket and offset are used to find the
last read socket immediately without needing ot scan the previous
buckets  the table.  This algorithm t read the whole table is O(n).

The improvement offered by this patch is easily show by performing
cat'ing /proc/net/tcp on a machine with a lot of connections.  With
about 182K connections in the table, I see the following:

- Without patch
time cat /proc/net/tcp > /dev/null

real	1m56.729s
user	0m0.214s
sys	1m56.344s

- With patch
time cat /proc/net/tcp > /dev/null

real	0m0.894s
user	0m0.290s
sys	0m0.594s
Signed-off-by: NTom Herbert <therbert@google.com>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- ipv6 msstab: account for ipv6 header size
- ipv4 msstab: add mss for Jumbograms.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

caller: if (!th->rst && !th->syn && th->ack)
callee: if (!th->ack)

make the caller only check for !syn (common for 3whs), and move
the !rst / ack test to the callee.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

both syn_flood_warning functions print a message, but
ipv4 version only prints a warning if CONFIG_SYN_COOKIES=y.

Make the v4 one behave like the v6 one.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Its better to make a route lookup in appropriate namespace.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I believe a moderate SYN flood attack can corrupt RFS flow table
(rps_sock_flow_table), making RPS/RFS much less effective.

Even in a normal situation, server handling short lived sessions suffer
from bad steering for the first data packet of a session, if another SYN
packet is received for another session.

We do following action in tcp_v4_rcv() :

	sock_rps_save_rxhash(sk, skb->rxhash);

We should _not_ do this if sk is a LISTEN socket, as about each
packet received on a LISTEN socket has a different rxhash than
previous one.
 -> RPS_NO_CPU markers are spread all over rps_sock_flow_table.

Also, it makes sense to protect sk->rxhash field changes with socket
lock (We currently can change it even if user thread owns the lock
and might use rxhash)

This patch moves sock_rps_save_rxhash() to a sock locked section,
and only for non LISTEN sockets.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syncookies default to on since
e994b7c9
(tcp: Don't make syn cookies initial setting depend on CONFIG_SYSCTL).
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Avoid two atomic ops in arp_fwd_proxy()

Avoid two atomic ops in arp_process()

Valid optims since arp_rcv() is run under rcu_read_lock()
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Avoid two atomic ops on output device refcount
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Avoid two atomic ops on struct in_device refcount per incoming packet,
if slow path taken, (or route cache disabled)
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Christoph Lameter mentioned that packets could be dropped in input path
because of rp_filter settings, without any SNMP counter being
incremented. System administrator can have a hard time to track the
problem.

This patch introduces a new counter, LINUX_MIB_IPRPFILTER, incremented
each time we drop a packet because Reverse Path Filter triggers.

(We receive an IPv4 datagram on a given interface, and find the route to
send an answer would use another interface)

netstat -s | grep IPReversePathFilter
    IPReversePathFilter: 21714
Reported-by: NChristoph Lameter <cl@linux-foundation.org>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For large values of rtt, 2^rho operation may overflow u32. Clamp down the increment to 2^16.
Signed-off-by: NDaniele Lacamera <root@danielinux.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Normally dhclient can be configured to send the "host-name" option
in DHCP requests to update the client's DNS record. However for an
NFSROOT system, dhclient shall never be called (which may change the
IP addr and therefore lose your root NFS mount connection).

So enable updating the DNS record with kernel parameter

	ip=::::$HOST_NAME::dhcp
Signed-off-by: NWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit: c720c7e8 missed these.
Signed-off-by: NJoe Perches <joe@perches.com>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Correct sk_forward_alloc handling for error_queue would need to use a
backlog of frames that softirq handler could not deliver because socket
is owned by user thread. Or extend backlog processing to be able to
process normal and error packets.

Another possibility is to not use mem charge for error queue, this is
what I implemented in this patch.

Note: this reverts commit 29030374
(net: fix sk_forward_alloc corruptions), since we dont need to lock
socket anymore.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit f3c5c1bf (netfilter: xtables: make ip_tables reentrant)
introduced a performance regression, because stackptr array is shared by
all cpus, adding cache line ping pongs. (16 cpus share a 64 bytes cache
line)

Fix this using alloc_percpu()
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Acked-By: NJan Engelhardt <jengelh@medozas.de>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Currently such notifications are only generated when the device comes up or the
address changes. However one use case for these notifications is to enable
faster network recovery after a virtual machine migration (by causing switches
to relearn their MAC tables). A migration appears to the network stack as a
temporary loss of carrier and therefore does not trigger either of the current
conditions. Rather than adding carrier up as a trigger (which can cause issues
when interfaces a flapping) simply add an interface which the driver can use
to explicitly trigger the notification.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Cc: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Cc: stable@kernel.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tcp_md5_hash_skb_data() should handle skb->frag_list, and eventually
recurse.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch saves 224 bytes of text on my machine.

__this_cpu_inc() generates a single instruction, using no scratch
registers :

  65 ff 04 25 a8 30 01 00      incl   %gs:0x130a8

instead of :

  48 c7 c2 80 30 01 00         mov    $0x13080,%rdx
  65 48 8b 04 25 88 ea 00 00   mov    %gs:0xea88,%rax
  83 44 10 28 01               addl   $0x1,0x28(%rax,%rdx,1)
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As David found out, sock_queue_err_skb() should be called with socket
lock hold, or we risk sk_forward_alloc corruption, since we use non
atomic operations to update this field.

This patch adds bh_lock_sock()/bh_unlock_sock() pair to three spots.
(BH already disabled)

1) skb_tstamp_tx() 
2) Before calling ip_icmp_error(), in __udp4_lib_err() 
3) Before calling ipv6_icmp_error(), in __udp6_lib_err()
Reported-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This new sock lock primitive was introduced to speedup some user context
socket manipulation. But it is unsafe to protect two threads, one using
regular lock_sock/release_sock, one using lock_sock_bh/unlock_sock_bh

This patch changes lock_sock_bh to be careful against 'owned' state.
If owned is found to be set, we must take the slow path.
lock_sock_bh() now returns a boolean to say if the slow path was taken,
and this boolean is used at unlock_sock_bh time to call the appropriate
unlock function.

After this change, BH are either disabled or enabled during the
lock_sock_bh/unlock_sock_bh protected section. This might be misleading,
so we rename these functions to lock_sock_fast()/unlock_sock_fast().
Reported-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Tested-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This fixes a smatch warning:
	net/ipv4/ipmr.c +1917 __ipmr_fill_mroute(12) error: buffer overflow
	'(mrt)->vif_table' 32 <= 32

The ipv6 version had the same issue.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- C99 knows about USHRT_MAX/SHRT_MAX/SHRT_MIN, not
  USHORT_MAX/SHORT_MAX/SHORT_MIN.

- Make SHRT_MIN of type s16, not int, for consistency.

[akpm@linux-foundation.org: fix drivers/dma/timb_dma.c]
[akpm@linux-foundation.org: fix security/keys/keyring.c]
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Acked-by: NWANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch removes from net/ (but not any netfilter files)
all the unnecessary return; statements that precede the
last closing brace of void functions.

It does not remove the returns that are immediately
preceded by a label as gcc doesn't like that.

Done via:
$ grep -rP --include=*.[ch] -l "return;\n}" net/ | \
  xargs perl -i -e 'local $/ ; while (<>) { s/\n[ \t\n]+return;\n}/\n}/g; print; }'
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

skb rxhash should be cleared when a skb is handled by a tunnel before
being delivered again, so that correct packet steering can take place.

There are other cleanups and accounting that we can factorize in a new
helper, skb_tunnel_rx()
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 33ad798c (tcp: options clean up) introduced a problem
if MD5+SACK+timestamps were used in initial SYN message.

Some stacks (old linux for example) try to negotiate MD5+SACK+TSTAMP
sessions, but since 40 bytes of tcp options space are not enough to
store all the bits needed, we chose to disable timestamps in this case.

We send a SYN-ACK _without_ timestamp option, but socket has timestamps
enabled and all further outgoing messages contain a TS block, all with
the initial timestamp of the remote peer.

Fix is to really disable timestamps option for the whole session.
Reported-by: NBijay Singh <Bijay.Singh@guavus.com>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Also added an explicit break; to avoid
a fallthrough in net/ipv4/tcp_input.c
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

TCP outgoing packets can avoid two atomic ops, and dirtying
of previously higly contended cache line using new refdst
infrastructure.

Note 1: loopback device excluded because of !IFF_XMIT_DST_RELEASE
Note 2: UDP packets dsts are built before ip_queue_xmit().
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>