linux-stable.git/include/net/route.h, branch v3.13

ipv4: introduce new IP_MTU_DISCOVER mode IP_PMTUDISC_INTERFACE

2013-11-06T02:52:27+00:00

Sockets marked with IP_PMTUDISC_INTERFACE won't do path mtu discovery,
their sockets won't accept and install new path mtu information and they
will always use the interface mtu for outgoing packets. It is guaranteed
that the packet is not fragmented locally. But we won't set the DF-Flag
on the outgoing frames.

Florian Weimer had the idea to use this flag to ensure DNS servers are
never generating outgoing fragments. They may well be fragmented on the
path, but the server never stores or usees path mtu values, which could
well be forged in an attack.

(The root of the problem with path MTU discovery is that there is
no reliable way to authenticate ICMP Fragmentation Needed But DF Set
messages because they are sent from intermediate routers with their
source addresses, and the IMCP payload will not always contain sufficient
information to identify a flow.)

Recent research in the DNS community showed that it is possible to
implement an attack where DNS cache poisoning is feasible by spoofing
fragments. This work was done by Amir Herzberg and Haya Shulman:


This issue was previously discussed among the DNS community, e.g.
,
without leading to fixes.

This patch depends on the patch "ipv4: fix DO and PROBE pmtu mode
regarding local fragmentation with UFO/CORK" for the enforcement of the
non-fragmentable checks. If other users than ip_append_page/data should
use this semantic too, we have to add a new flag to IPCB(skb)->flags to
suppress local fragmentation and check for this in ip_finish_output.

Many thanks to Florian Weimer for the idea and feedback while implementing
this patch.

Cc: David S. Miller 
Suggested-by: Florian Weimer 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller

ipv4: shrink rt_cache_stat

2013-10-17T20:11:04+00:00

Half of the rt_cache_stat fields are no longer used after IP
route cache removal, lets shrink this per cpu area.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

ipv4: processing ancillary IP_TOS or IP_TTL

2013-09-28T22:21:52+00:00

If IP_TOS or IP_TTL are specified as ancillary data, then sendmsg() sends out
packets with the specified TTL or TOS overriding the socket values specified
with the traditional setsockopt().

The struct inet_cork stores the values of TOS, TTL and priority that are
passed through the struct ipcm_cookie. If there are user-specified TOS
(tos != -1) or TTL (ttl != 0) in the struct ipcm_cookie, these values are
used to override the per-socket values. In case of TOS also the priority
is changed accordingly.

Two helper functions get_rttos and get_rtconn_flags are defined to take
into account the presence of a user specified TOS value when computing
RT_TOS and RT_CONN_FLAGS.

Signed-off-by: Francesco Fusco 
Signed-off-by: David S. Miller

route.h: Remove extern from function prototypes

2013-09-23T05:51:08+00:00

There are a mix of function prototypes with and without extern
in the kernel sources.  Standardize on not using extern for
function prototypes.

Function prototypes don't need to be written with extern.
extern is assumed by the compiler.  Its use is as unnecessary as
using auto to declare automatic/local variables in a block.

Signed-off-by: Joe Perches 
Signed-off-by: David S. Miller

xfrm: introduce helper for safe determination of mtu

2013-08-14T11:09:07+00:00

skb->sk socket can be of AF_INET or AF_INET6 address family. Thus we
always have to make sure we a referring to the correct interpretation
of skb->sk.

We only depend on header defines to query the mtu, so we don't introduce
a new dependency to ipv6 by this change.

Cc: Steffen Klassert 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: Steffen Klassert

ipv4: avoid a test in ip_rt_put()

2012-11-03T18:59:04+00:00

We can save a test in ip_rt_put(), considering dst_release() accepts
a NULL parameter, and dst is first element in rtable.

Add a BUILD_BUG_ON() to catch any change that could break this
assertion.

Signed-off-by: Eric Dumazet 
Cc: Cong Wang 
Acked-by: Cong Wang 
Signed-off-by: David S. Miller

ipv4: introduce rt_uses_gateway

2012-10-08T21:42:36+00:00

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

ipv4/route: arg delay is useless in rt_cache_flush()

2012-09-18T19:44:34+00:00

Since route cache deletion (89aef8921bfbac22f), delay is no
more used. Remove it.

Signed-off-by: Nicolas Dichtel 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

ipv4: Properly purge netdev references on uncached routes.

2012-07-31T22:06:50+00:00

When a device is unregistered, we have to purge all of the
references to it that may exist in the entire system.

If a route is uncached, we currently have no way of accomplishing
this.

So create a global list that is scanned when a network device goes
down.  This mirrors the logic in net/core/dst.c's dst_ifdown().

Signed-off-by: David S. Miller

ipv4: Fix input route performance regression.

2012-07-26T22:50:39+00:00

With the routing cache removal we lost the "noref" code paths on
input, and this can kill some routing workloads.

Reinstate the noref path when we hit a cached route in the FIB
nexthops.

With help from Eric Dumazet.

Reported-by: Alexander Duyck 
Signed-off-by: David S. Miller 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller