linux-stable.git/net/ipv4, branch v3.6.7

net: inet_diag -- Return error code if protocol handler is missed

2012-11-17T21:19:04+00:00

[ Upstream commit cacb6ba0f36ab14a507f4ee7697e8332899015d2 ]

We've observed that in case if UDP diag module is not
supported in kernel the netlink returns NLMSG_DONE without
notifying a caller that handler is missed.

This patch makes __inet_diag_dump to return error code instead.

So as example it become possible to detect such situation
and handle it gracefully on userspace level.

Signed-off-by: Cyrill Gorcunov 
CC: David Miller 
CC: Eric Dumazet 
CC: Pavel Emelyanov 
Acked-by: Pavel Emelyanov 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp-repair: Handle zero-length data put in rcv queue

2012-11-17T21:18:53+00:00

[ Upstream commit c454e6111d1ef4268fe98e87087216e51c2718c3 ]

When sending data into a tcp socket in repair state we should check
for the amount of data being 0 explicitly. Otherwise we'll have an skb
with seq == end_seq in rcv queue, but tcp doesn't expect this to happen
(in particular a warn_on in tcp_recvmsg shoots).

Signed-off-by: Pavel Emelyanov 
Reported-by: Giorgos Mavrikas 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: fix divide by zero in tcp algorithm illinois

2012-11-17T21:18:52+00:00

[ Upstream commit 8f363b77ee4fbf7c3bbcf5ec2c5ca482d396d664 ]

Reading TCP stats when using TCP Illinois congestion control algorithm
can cause a divide by zero kernel oops.

The division by zero occur in tcp_illinois_info() at:
 do_div(t, ca->cnt_rtt);
where ca->cnt_rtt can become zero (when rtt_reset is called)

Steps to Reproduce:
 1. Register tcp_illinois:
     # sysctl -w net.ipv4.tcp_congestion_control=illinois
 2. Monitor internal TCP information via command "ss -i"
     # watch -d ss -i
 3. Establish new TCP conn to machine

Either it fails at the initial conn, or else it needs to wait
for a loss or a reset.

This is only related to reading stats.  The function avg_delay() also
performs the same divide, but is guarded with a (ca->cnt_rtt > 0) at its
calling point in update_params().  Thus, simply fix tcp_illinois_info().

Function tcp_illinois_info() / get_info() is called without
socket lock.  Thus, eliminate any race condition on ca->cnt_rtt
by using a local stack variable.  Simply reuse info.tcpv_rttcnt,
as its already set to ca->cnt_rtt.
Function avg_delay() is not affected by this race condition, as
its called with the socket lock.

Cc: Petr Matousek 
Signed-off-by: Jesper Dangaard Brouer 
Acked-by: Eric Dumazet 
Acked-by: Stephen Hemminger 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: fix FIONREAD/SIOCINQ

2012-11-17T21:18:52+00:00

[ Upstream commit a3374c42aa5f7237e87ff3b0622018636b0c847e ]

tcp_ioctl() tries to take into account if tcp socket received a FIN
to report correct number bytes in receive queue.

But its flaky because if the application ate the last skb,
we return 1 instead of 0.

Correct way to detect that FIN was received is to test SOCK_DONE.

Reported-by: Elliot Hughes 
Signed-off-by: Eric Dumazet 
Cc: Neal Cardwell 
Cc: Tom Herbert 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv4: Fix flushing of cached routing informations

2012-11-17T21:18:52+00:00

[ Upstream commit 13d82bf50dce632355fcccafa4fe44a9b5e706d8 ]

Currently we can not flush cached pmtu/redirect informations via
the ipv4_sysctl_rtcache_flush sysctl. We need to check the rt_genid
of the old route and reset the nh exeption if the old route is
expired when we bind a new route to a nh exeption.

Signed-off-by: Steffen Klassert 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: resets are misrouted

2012-10-28T17:56:18+00:00

[ Upstream commit 4c67525849e0b7f4bd4fab2487ec9e43ea52ef29 ]

After commit e2446eaa ("tcp_v4_send_reset: binding oif to iif in no
sock case").. tcp resets are always lost, when routing is asymmetric.
Yes, backing out that patch will result in misrouting of resets for
dead connections which used interface binding when were alive, but we
actually cannot do anything here.  What's died that's died and correct
handling normal unbound connections is obviously a priority.

Comment to comment:
> This has few benefits:
>   1. tcp_v6_send_reset already did that.

It was done to route resets for IPv6 link local addresses. It was a
mistake to do so for global addresses. The patch fixes this as well.

Actually, the problem appears to be even more serious than guaranteed
loss of resets.  As reported by Sergey Soloviev , those
misrouted resets create a lot of arp traffic and huge amount of
unresolved arp entires putting down to knees NAT firewalls which use
asymmetric routing.

Signed-off-by: Alexey Kuznetsov 
Signed-off-by: Greg Kroah-Hartman

ipv4: Add FLOWI_FLAG_KNOWN_NH

2012-10-28T17:56:17+00:00

[ Upstream commit c92b96553a80c1dbe2ebe128bbe37c8f98f148bf ]

Add flag to request that output route should be
returned with known rt_gateway, in case we want to use
it as nexthop for neighbour resolving.

	The returned route can be cached as follows:

- in NH exception: because the cached routes are not shared
	with other destinations
- in FIB NH: when using gateway because all destinations for
	NH share same gateway

	As last option, to return rt_gateway!=0 we have to
set DST_NOCACHE.

Signed-off-by: Julian Anastasov 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv4: introduce rt_uses_gateway

2012-10-28T17:56:17+00:00

[ Upstream commit 155e8336c373d14d87a7f91e356d85ef4b93b8f9 ]

Add new flag to remember when route is via gateway.
We will use it to allow rt_gateway to contain address of
directly connected host for the cases when DST_NOCACHE is
used or when the NH exception caches per-destination route
without DST_NOCACHE flag, i.e. when routes are not used for
other destinations. By this way we force the neighbour
resolving to work with the routed destination but we
can use different address in the packet, feature needed
for IPVS-DR where original packet for virtual IP is routed
via route to real IP.

Signed-off-by: Julian Anastasov 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv4: make sure nh_pcpu_rth_output is always allocated

2012-10-28T17:56:17+00:00

[ Upstream commit f8a17175c63fd3e8b573719f7538816f8c96abf4 ]

Avoid checking nh_pcpu_rth_output in fast path,
abort fib_info creation on alloc_percpu failure.

Signed-off-by: Julian Anastasov 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv4: fix forwarding for strict source routes

2012-10-28T17:56:17+00:00

[ Upstream commit e0adef0f7456d5d3a3bfe8ea61c7dddf146b40e1 ]

After the change "Adjust semantics of rt->rt_gateway"
(commit f8126f1d51) rt_gateway can be 0 but ip_forward() compares
it directly with nexthop. What we want here is to check if traffic
is to directly connected nexthop and to fail if using gateway.

Signed-off-by: Julian Anastasov 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman