ipv4: Kill ip_route_input_noref().

The "noref" argument to ip_route_input_common() is now always ignored
because we do not cache routes, and in that case we must always grab
a reference to the resul

ipv4: Kill ip_route_input_noref().

The "noref" argument to ip_route_input_common() is now always ignored
because we do not cache routes, and in that case we must always grab
a reference to the resulting 'dst'.

Signed-off-by: David S. Miller <davem@davemloft.net>

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ipv4: Delete routing cache.

The ipv4 routing cache is non-deterministic, performance wise, and is
subject to reasonably easy to launch denial of service attacks.

The routing cache works great for w

ipv4: Delete routing cache.

The ipv4 routing cache is non-deterministic, performance wise, and is
subject to reasonably easy to launch denial of service attacks.

The routing cache works great for well behaved traffic, and the world
was a much friendlier place when the tradeoffs that led to the routing
cache's design were considered.

What it boils down to is that the performance of the routing cache is
a product of the traffic patterns seen by a system rather than being a
product of the contents of the routing tables. The former of which is
controllable by external entitites.

Even for "well behaved" legitimate traffic, high volume sites can see
hit rates in the routing cache of only ~%10.

Signed-off-by: David S. Miller <davem@davemloft.net>

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ipv4: Kill ip_rt_redirect().

No longer needed, as the protocol handlers now all properly
propagate the redirect back into the routing code.

Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: Add ipv4_redirect() and ipv4_sk_redirect() helper functions.

Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: Rearrange arguments to ip_rt_redirect()

Pass in the SKB rather than just the IP addresses, so that policy
and other aspects can reside in ip_rt_redirect() rather then
icmp_redirect().

Signed-

ipv4: Rearrange arguments to ip_rt_redirect()

Pass in the SKB rather than just the IP addresses, so that policy
and other aspects can reside in ip_rt_redirect() rather then
icmp_redirect().

Signed-off-by: David S. Miller <davem@davemloft.net>

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ipv4: Remove inetpeer from routes.

No longer used.

Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: Maintain redirect and PMTU info in struct rtable again.

Maintaining this in the inetpeer entries was not the right way to do
this at all.

Signed-off-by: David S. Miller <davem@davemloft.net>

inet: Kill FLOWI_FLAG_PRECOW_METRICS.

No longer needed. TCP writes metrics, but now in it's own special
cache that does not dirty the route metrics. Therefore there is no
longer any reason to pre-

inet: Kill FLOWI_FLAG_PRECOW_METRICS.

No longer needed. TCP writes metrics, but now in it's own special
cache that does not dirty the route metrics. Therefore there is no
longer any reason to pre-cow metrics in this way.

Signed-off-by: David S. Miller <davem@davemloft.net>

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ipv4: Kill rt->rt_spec_dst, no longer used.

Signed-off-by: David S. Miller <davem@davemloft.net>

Revert "ipv4: tcp: dont cache unconfirmed intput dst"

This reverts commit c074da2810c118b3812f32d6754bd9ead2f169e7.

This change has several unwanted side effects:

1) Sockets will cache the DST_NOC

Revert "ipv4: tcp: dont cache unconfirmed intput dst"

This reverts commit c074da2810c118b3812f32d6754bd9ead2f169e7.

This change has several unwanted side effects:

1) Sockets will cache the DST_NOCACHE route in sk->sk_rx_dst and we'll
thus never create a real cached route.

2) All TCP traffic will use DST_NOCACHE and never use the routing
cache at all.

Signed-off-by: David S. Miller <davem@davemloft.net>

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ipv4: tcp: dont cache unconfirmed intput dst

DDOS synflood attacks hit badly IP route cache.

On typical machines, this cache is allowed to hold up to 8 Millions dst
entries, 256 bytes for each, for

ipv4: tcp: dont cache unconfirmed intput dst

DDOS synflood attacks hit badly IP route cache.

On typical machines, this cache is allowed to hold up to 8 Millions dst
entries, 256 bytes for each, for a total of 2GB of memory.

rt_garbage_collect() triggers and tries to cleanup things.

Eventually route cache is disabled but machine is under fire and might
OOM and crash.

This patch exploits the new TCP early demux, to set a nocache
boolean in case incoming TCP frame is for a not yet ESTABLISHED or
TIMEWAIT socket.

This 'nocache' boolean is then used in case dst entry is not found in
route cache, to create an unhashed dst entry (DST_NOCACHE)

SYN-cookie-ACK sent use a similar mechanism (ipv4: tcp: dont cache
output dst for syncookies), so after this patch, a machine is able to
absorb a DDOS synflood attack without polluting its IP route cache.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Hans Schillstrom <hans.schillstrom@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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ipv4: Handle PMTU in all ICMP error handlers.

With ip_rt_frag_needed() removed, we have to explicitly update PMTU
information in every ICMP error handler.

Create two helper functions to facilitate

ipv4: Handle PMTU in all ICMP error handlers.

With ip_rt_frag_needed() removed, we have to explicitly update PMTU
information in every ICMP error handler.

Create two helper functions to facilitate this.

1) ipv4_sk_update_pmtu()

This updates the PMTU when we have a socket context to
work with.

2) ipv4_update_pmtu()

Raw version, used when no socket context is available. For this
interface, we essentially just pass in explicit arguments for
the flow identity information we would have extracted from the
socket.

And you'll notice that ipv4_sk_update_pmtu() is simply implemented
in terms of ipv4_update_pmtu()

Note that __ip_route_output_key() is used, rather than something like
ip_route_output_flow() or ip_route_output_key(). This is because we
absolutely do not want to end up with a route that does IPSEC
encapsulation and the like. Instead, we only want the route that
would get us to the node described by the outermost IP header.

Reported-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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inet: Fix BUG triggered by __rt{,6}_get_peer().

If no peer actually gets attached (either because create is zero or
the peer allocation fails) we'll trigger a BUG because we
unconditionally do an rt

inet: Fix BUG triggered by __rt{,6}_get_peer().

If no peer actually gets attached (either because create is zero or
the peer allocation fails) we'll trigger a BUG because we
unconditionally do an rt{,6}_peer_ptr() afterwards.

Fix this by guarding it with the proper check.

Signed-off-by: David S. Miller <davem@davemloft.net>

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ipv4: Kill ip_rt_frag_needed().

There is zero point to this function.

It's only real substance is to perform an extremely outdated BSD4.2
ICMP check, which we can safely remove. If you really have

ipv4: Kill ip_rt_frag_needed().

There is zero point to this function.

It's only real substance is to perform an extremely outdated BSD4.2
ICMP check, which we can safely remove. If you really have a MTU
limited link being routed by a BSD4.2 derived system, here's a nickel
go buy yourself a real router.

The other actions of ip_rt_frag_needed(), checking and conditionally
updating the peer, are done by the per-protocol handlers of the ICMP
event.

TCP, UDP, et al. have a handler which will receive this event and
transmit it back into the associated route via dst_ops->update_pmtu().

This simplification is important, because it eliminates the one place
where we do not have a proper route context in which to make an
inetpeer lookup.

Signed-off-by: David S. Miller <davem@davemloft.net>

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inet: Hide route peer accesses behind helpers.

We encode the pointer(s) into an unsigned long with one state bit.

The state bit is used so we can store the inetpeer tree root to use
when resolving

inet: Hide route peer accesses behind helpers.

We encode the pointer(s) into an unsigned long with one state bit.

The state bit is used so we can store the inetpeer tree root to use
when resolving the peer later.

Later the peer roots will be per-FIB table, and this change works to
facilitate that.

Signed-off-by: David S. Miller <davem@davemloft.net>

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net: Reorder initialization in ip_route_output to fix gcc warning

If I build with W=1, for every file that includes <net/route.h>, I get the warning

include/net/route.h: In function 'ip_route_o

net: Reorder initialization in ip_route_output to fix gcc warning

If I build with W=1, for every file that includes <net/route.h>, I get the warning

include/net/route.h: In function 'ip_route_output':
include/net/route.h:135:3: warning: initialized field overwritten [-Woverride-init]
include/net/route.h:135:3: warning: (near initialization for 'fl4') [-Woverride-init]

(This is with "gcc (Debian 4.6.3-1) 4.6.3")

A fix seems pretty trivial: move the initialization of .flowi4_tos
earlier. As far as I can tell, this has no effect on code generation.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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inet: Create and use rt{,6}_get_peer_create().

There's a lot of places that open-code rt{,6}_get_peer() only because
they want to set 'create' to one. So add an rt{,6}_get_peer_create()
for their s

inet: Create and use rt{,6}_get_peer_create().

There's a lot of places that open-code rt{,6}_get_peer() only because
they want to set 'create' to one. So add an rt{,6}_get_peer_create()
for their sake.

There were also a few spots open-coding plain rt{,6}_get_peer() and
those are transformed here as well.

Signed-off-by: David S. Miller <davem@davemloft.net>

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net: cleanup unsigned to unsigned int

Use of "unsigned int" is preferred to bare "unsigned" in net tree.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@d

net: cleanup unsigned to unsigned int

Use of "unsigned int" is preferred to bare "unsigned" in net tree.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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ipv4: reset flowi parameters on route connect

Eric Dumazet found that commit 813b3b5db83
(ipv4: Use caller's on-stack flowi as-is in output
route lookups.) that comes in 3.0 added a regression.
The

ipv4: reset flowi parameters on route connect

Eric Dumazet found that commit 813b3b5db83
(ipv4: Use caller's on-stack flowi as-is in output
route lookups.) that comes in 3.0 added a regression.
The problem appears to be that resulting flowi4_oif is
used incorrectly as input parameter to some routing lookups.
The result is that when connecting to local port without
listener if the IP address that is used is not on a loopback
interface we incorrectly assign RTN_UNICAST to the output
route because no route is matched by oif=lo. The RST packet
can not be sent immediately by tcp_v4_send_reset because
it expects RTN_LOCAL.

So, change ip_route_connect and ip_route_newports to
update the flowi4 fields that are input parameters because
we do not want unnecessary binding to oif.

To make it clear what are the input parameters that
can be modified during lookup and to show which fields of
floiw4 are reused add a new function to update the flowi4
structure: flowi4_update_output.

Thanks to Yurij M. Plotnikov for providing a bug report including a
program to reproduce the problem.

Thanks to Eric Dumazet for tracking the problem down to
tcp_v4_send_reset and providing initial fix.

Reported-by: Yurij M. Plotnikov <Yurij.Plotnikov@oktetlabs.ru>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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route: struct rtable can be const in rt_is_input_route and rt_is_output_route

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: Pass explicit destination address to rt_bind_peer().

Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: Pass explicit destination address to rt_get_peer().

This will next trickle down to rt_bind_peer().

Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: Remove route key identity dependencies in ip_rt_get_source().

Pass in the sk_buff so that we can fetch the necessary keys from
the packet header when working with input routes.

Signed-off-by:

ipv4: Remove route key identity dependencies in ip_rt_get_source().

Pass in the sk_buff so that we can fetch the necessary keys from
the packet header when working with input routes.

Signed-off-by: David S. Miller <davem@davemloft.net>

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ipv4: Kill rt->rt_{src, dst} usage in IP GRE tunnels.

First, make callers pass on-stack flowi4 to ip_route_output_gre()
so they can get at the fully resolved flow key.

Next, use that in ipgre_tunne

ipv4: Kill rt->rt_{src, dst} usage in IP GRE tunnels.

First, make callers pass on-stack flowi4 to ip_route_output_gre()
so they can get at the fully resolved flow key.

Next, use that in ipgre_tunnel_xmit() to avoid the need to use
rt->rt_{dst,src}.

Signed-off-by: David S. Miller <davem@davemloft.net>

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ipv4: Make caller provide on-stack flow key to ip_route_output_ports().

Signed-off-by: David S. Miller <davem@davemloft.net>