This is immediately motivated by the bridge code that chains functions that
call into netfilter.  Without passing net into the okfns the bridge code would
need to guess about the best expression for the network namespace to process
packets in.

As net is frequently one of the first things computed in continuation functions
after netfilter has done it's job passing in the desired network namespace is in
many cases a code simplification.

To support this change the function dst_output_okfn is introduced to
simplify passing dst_output as an okfn.  For the moment dst_output_okfn
just silently drops the struct net.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pass a network namespace parameter into the netfilter hooks.  At the
call site of the netfilter hooks the path a packet is taking through
the network stack is well known which allows the network namespace to
be easily and reliabily.

This allows the replacement of magic code like
"dev_net(state->in?:state->out)" that appears at the start of most
netfilter hooks with "state->net".

In almost all cases the network namespace passed in is derived
from the first network device passed in, guaranteeing those
paths will not see any changes in practice.

The exceptions are:
xfrm/xfrm_output.c:xfrm_output_resume()         xs_net(skb_dst(skb)->xfrm)
ipvs/ip_vs_xmit.c:ip_vs_nat_send_or_cont()      ip_vs_conn_net(cp)
ipvs/ip_vs_xmit.c:ip_vs_send_or_cont()          ip_vs_conn_net(cp)
ipv4/raw.c:raw_send_hdrinc()                    sock_net(sk)
ipv6/ip6_output.c:ip6_xmit()			sock_net(sk)
ipv6/ndisc.c:ndisc_send_skb()                   dev_net(skb->dev) not dev_net(dst->dev)
ipv6/raw.c:raw6_send_hdrinc()                   sock_net(sk)
br_netfilter_hooks.c:br_nf_pre_routing_finish() dev_net(skb->dev) before skb->dev is set to nf_bridge->physindev

In all cases these exceptions seem to be a better expression for the
network namespace the packet is being processed in then the historic
"dev_net(in?in:out)".  I am documenting them in case something odd
pops up and someone starts trying to track down what happened.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The function dev_queue_xmit_skb_sk is unncessary and very confusing.
Introduce arp_xmit_finish to remove the need for dev_queue_xmit_skb_sk,
and have arp_xmit_finish call dev_queue_xmit.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently inet_addr_type and inet_dev_addr_type expect local addresses
to be in the local table. With the VRF device local routes for devices
associated with a VRF will be in the table associated with the VRF.
Provide an alternate inet_addr lookup to use a specific table rather
than defaulting to the local table.

inet_addr_type_dev_table keeps the same semantics as inet_addr_type but
if the passed in device is enslaved to a VRF then the table for that VRF
is used for the lookup.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When arp is off on a device, and ioctl(SIOCGARP) is queried,
a buggy answer is given with MAC address of the device, instead
of the mac address of the destination/gateway.

We filter out NUD_NOARP neighbours for /proc/net/arp,
we must do the same for SIOCGARP ioctl.

Tested:

lpaa23:~# ./arp 10.246.7.190
MAC=00:01:e8:22:cb:1d      // correct answer

lpaa23:~# ip link set dev eth0 arp off
lpaa23:~# cat /proc/net/arp   # check arp table is now 'empty'
IP address       HW type     Flags       HW address    Mask     Device
lpaa23:~# ./arp 10.246.7.190
MAC=00:1a:11:c3:0d:7f   // buggy answer before patch (this is eth0 mac)

After patch :

lpaa23:~# ip link set dev eth0 arp off
lpaa23:~# ./arp 10.246.7.190
ioctl(SIOCGARP) failed: No such device or address
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NVytautas Valancius <valas@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If output device wants to see the dst, inherit the dst of the
original skb and pass it on to generate the ARP request.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

On the output paths in particular, we have to sometimes deal with two
socket contexts.  First, and usually skb->sk, is the local socket that
generated the frame.

And second, is potentially the socket used to control a tunneling
socket, such as one the encapsulates using UDP.

We do not want to disassociate skb->sk when encapsulating in order
to fix this, because that would break socket memory accounting.

The most extreme case where this can cause huge problems is an
AF_PACKET socket transmitting over a vxlan device.  We hit code
paths doing checks that assume they are dealing with an ipv4
socket, but are actually operating upon the AF_PACKET one.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The ipv4 code uses a mixture of coding styles. In some instances check
for non-NULL pointer is done as x != NULL and sometimes as x. x is
preferred according to checkpatch and this patch makes the code
consistent by adopting the latter form.

No changes detected by objdiff.
Signed-off-by: NIan Morris <ipm@chirality.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The ipv4 code uses a mixture of coding styles. In some instances check
for NULL pointer is done as x == NULL and sometimes as !x. !x is
preferred according to checkpatch and this patch makes the code
consistent by adopting the latter form.

No changes detected by objdiff.
Signed-off-by: NIan Morris <ipm@chirality.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While looking at the mpls code I found myself writing yet another
version of neigh_lookup_noref.  We currently have __ipv4_lookup_noref
and __ipv6_lookup_noref.

So to make my work a little easier and to make it a smidge easier to
verify/maintain the mpls code in the future I stopped and wrote
___neigh_lookup_noref.  Then I rewote __ipv4_lookup_noref and
__ipv6_lookup_noref in terms of this new function.  I tested my new
version by verifying that the same code is generated in
ip_finish_output2 and ip6_finish_output2 where these functions are
inlined.

To get to ___neigh_lookup_noref I added a new neighbour cache table
function key_eq.  So that the static size of the key would be
available.

I also added __neigh_lookup_noref for people who want to to lookup
a neighbour table entry quickly but don't know which neibhgour table
they are going to look up.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- Add protocol to neigh_tbl so that dst->ops->protocol is not needed
- Acquire the device from neigh->dev

This results in a neigh_hh_init that will cache the samve values
regardless of the packets flowing through it.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are no more callers so kill this function.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The special case has been pushed out into ax25_neigh_construct so there
is no need to keep this code in arp.c
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently there are only three neigh tables in the whole kernel:
arp table, ndisc table and decnet neigh table. What's more,
we don't support registering multiple tables per family.
Therefore we can just make these tables statically built-in.

Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We do not wish to disturb dropwatch or perf drop profiles with an ARP
we will ignore.
Signed-off-by: NRick Jones <rick.jones2@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Gratuitous arp packets are useful in switchover scenarios to update
client arp tables as quickly as possible. Currently, the mac address
of a neighbour is only updated after a locktime period has elapsed
since the last update. In most use cases such delays are unacceptable
for network admins. Moreover, the "updated" field of the neighbour
stucture doesn't record the last time the address of a neighbour
changed but records any change that happens to the neighbour. This is
clearly a bug since locktime uses that field as meaning "addr_updated".
With this observation, I was able to perpetuate a stale address by
sending a stream of gratuitous arp packets spaced less than locktime
apart. With this change the address is updated when a gratuitous arp
is received and the arp_accept sysctl is set.
Signed-off-by: NSalam Noureddine <noureddine@aristanetworks.com>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Don't export arp_invalidate, only used in arp.c
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Help of this function says: "in_dev: only on this interface, 0=any interface",
but since commit 39a6d063 ("[NETNS]: Process inet_confirm_addr in the
correct namespace."), the code supposes that it will never be NULL. This
function is never called with in_dev == NULL, but it's exported and may be used
by an external module.

Because this patch restore the ability to call inet_confirm_addr() with in_dev
== NULL, I partially revert the above commit, as suggested by Julian.

CC: Julian Anastasov <ja@ssi.bg>
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: NJulian Anastasov <ja@ssi.bg>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch converts the neigh param members to an array. This allows easier
manipulation which will be needed later on to provide better management of
default values.
Signed-off-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This config option is superfluous in that it only guards a call
to neigh_app_ns(). Enabling CONFIG_ARPD by default has no
change in behavior. There will now be call to __neigh_notify()
for each ARP resolution, which has no impact unless there is a
user space daemon waiting to receive the notification, i.e.,
the case for which CONFIG_ARPD was designed anyways.
Suggested-by: NEric W. Biederman <ebiederm@xmission.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Cc: Joe Perches <joe@perches.com>
Cc: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: NTim Gardner <tim.gardner@canonical.com>
Reviewed-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IFF_NOARP affects what kind of neighbor entries are created
(nud NOARP or nud INCOMPLETE). If the flag changes, flush the arp
cache to refresh all entries.
Signed-off-by: NTimo Teräs <timo.teras@iki.fi>
Signed-off-by: NJiri Pirko <jiri@resnulli.us>

v2->v3: shortened notifier_info struct name
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

So far, only net_device * could be passed along with netdevice notifier
event. This patch provides a possibility to pass custom structure
able to provide info that event listener needs to know.
Signed-off-by: NJiri Pirko <jiri@resnulli.us>

v2->v3: fix typo on simeth
	shortened dev_getter
	shortened notifier_info struct name
v1->v2: fix notifier_call parameter in call_netdevice_notifier()
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Inspection of upper layer protocol is considered harmful, especially
if it is about ARP or other stateful upper layer protocol; driver
cannot (and should not) have full state of them.

IPv4 over Firewire module used to inspect ARP (both in sending path
and in receiving path), and record peer's GUID, max packet size, max
speed and fifo address.  This patch removes such inspection by extending
our "hardware address" definition to include other information as well:
max packet size, max speed and fifo.  By doing this, The neighbour
module in networking subsystem can cache them.

Note: As we have started ignoring sspd and max_rec in ARP/NDP, those
      information will not be used in the driver when sending.

When a packet is being sent, the IP layer fills our pseudo header with
the extended "hardware address", including GUID and fifo.  The driver
can look-up node-id (the real but rather volatile low-level address)
by GUID, and then the module can send the packet to the wire using
parameters provided in the extendedn hardware address.

This approach is realistic because IP over IEEE1394 (RFC2734) and IPv6
over IEEE1394 (RFC3146) share same "hardware address" format
in their address resolution protocols.

Here, extended "hardware address" is defined as follows:

union fwnet_hwaddr {
	u8 u[16];
	struct {
		__be64 uniq_id;		/* EUI-64			*/
		u8 max_rec;		/* max packet size		*/
		u8 sspd;		/* max speed			*/
		__be16 fifo_hi;		/* hi 16bits of FIFO addr	*/
		__be32 fifo_lo;		/* lo 32bits of FIFO addr	*/
	} __packed uc;
};

Note that Hardware address is declared as union, so that we can map full
IP address into this, when implementing MCAP (Multicast Cannel Allocation
Protocol) for IPv6, but IP and ARP subsystem do not need to know this
format in detail.

One difference between original ARP (RFC826) and 1394 ARP (RFC2734)
is that 1394 ARP Request/Reply do not contain the target hardware address
field (aka ar$tha).  This difference is handled in the ARP subsystem.

CC: Stephan Gatzka <stephan.gatzka@gmail.com>
Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

proc_net_remove is only used to remove proc entries
that under /proc/net,it's not a general function for
removing proc entries of netns. if we want to remove
some proc entries which under /proc/net/stat/, we still
need to call remove_proc_entry.

this patch use remove_proc_entry to replace proc_net_remove.
we can remove proc_net_remove after this patch.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Right now, some modules such as bonding use proc_create
to create proc entries under /proc/net/, and other modules
such as ipv4 use proc_net_fops_create.

It looks a little chaos.this patch changes all of
proc_net_fops_create to proc_create. we can remove
proc_net_fops_create after this patch.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We should call skb_share_check() before pskb_may_pull(), or we
can crash in pskb_expand_head()
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Sedat reported the following commit caused a regression:

commit 9650388b
Author: Eric Dumazet <edumazet@google.com>
Date:   Fri Dec 21 07:32:10 2012 +0000

    ipv4: arp: fix a lockdep splat in arp_solicit

This is due to the 6th parameter of arp_send() needs to be NULL
for the broadcast case, the above commit changed it to an all-zero
array by mistake.
Reported-by: NSedat Dilek <sedat.dilek@gmail.com>
Tested-by: NSedat Dilek <sedat.dilek@gmail.com>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Yan Burman reported following lockdep warning :

=============================================
[ INFO: possible recursive locking detected ]
3.7.0+ #24 Not tainted
---------------------------------------------
swapper/1/0 is trying to acquire lock:
  (&n->lock){++--..}, at: [<ffffffff8139f56e>] __neigh_event_send
+0x2e/0x2f0

but task is already holding lock:
  (&n->lock){++--..}, at: [<ffffffff813f63f4>] arp_solicit+0x1d4/0x280

other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&n->lock);
   lock(&n->lock);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

4 locks held by swapper/1/0:
  #0:  (((&n->timer))){+.-...}, at: [<ffffffff8104b350>]
call_timer_fn+0x0/0x1c0
  #1:  (&n->lock){++--..}, at: [<ffffffff813f63f4>] arp_solicit
+0x1d4/0x280
  #2:  (rcu_read_lock_bh){.+....}, at: [<ffffffff81395400>]
dev_queue_xmit+0x0/0x5d0
  #3:  (rcu_read_lock_bh){.+....}, at: [<ffffffff813cb41e>]
ip_finish_output+0x13e/0x640

stack backtrace:
Pid: 0, comm: swapper/1 Not tainted 3.7.0+ #24
Call Trace:
  <IRQ>  [<ffffffff8108c7ac>] validate_chain+0xdcc/0x11f0
  [<ffffffff8108d570>] ? __lock_acquire+0x440/0xc30
  [<ffffffff81120565>] ? kmem_cache_free+0xe5/0x1c0
  [<ffffffff8108d570>] __lock_acquire+0x440/0xc30
  [<ffffffff813c3570>] ? inet_getpeer+0x40/0x600
  [<ffffffff8108d570>] ? __lock_acquire+0x440/0xc30
  [<ffffffff8139f56e>] ? __neigh_event_send+0x2e/0x2f0
  [<ffffffff8108ddf5>] lock_acquire+0x95/0x140
  [<ffffffff8139f56e>] ? __neigh_event_send+0x2e/0x2f0
  [<ffffffff8108d570>] ? __lock_acquire+0x440/0xc30
  [<ffffffff81448d4b>] _raw_write_lock_bh+0x3b/0x50
  [<ffffffff8139f56e>] ? __neigh_event_send+0x2e/0x2f0
  [<ffffffff8139f56e>] __neigh_event_send+0x2e/0x2f0
  [<ffffffff8139f99b>] neigh_resolve_output+0x16b/0x270
  [<ffffffff813cb62d>] ip_finish_output+0x34d/0x640
  [<ffffffff813cb41e>] ? ip_finish_output+0x13e/0x640
  [<ffffffffa046f146>] ? vxlan_xmit+0x556/0xbec [vxlan]
  [<ffffffff813cb9a0>] ip_output+0x80/0xf0
  [<ffffffff813ca368>] ip_local_out+0x28/0x80
  [<ffffffffa046f25a>] vxlan_xmit+0x66a/0xbec [vxlan]
  [<ffffffffa046f146>] ? vxlan_xmit+0x556/0xbec [vxlan]
  [<ffffffff81394a50>] ? skb_gso_segment+0x2b0/0x2b0
  [<ffffffff81449355>] ? _raw_spin_unlock_irqrestore+0x65/0x80
  [<ffffffff81394c57>] ? dev_queue_xmit_nit+0x207/0x270
  [<ffffffff813950c8>] dev_hard_start_xmit+0x298/0x5d0
  [<ffffffff813956f3>] dev_queue_xmit+0x2f3/0x5d0
  [<ffffffff81395400>] ? dev_hard_start_xmit+0x5d0/0x5d0
  [<ffffffff813f5788>] arp_xmit+0x58/0x60
  [<ffffffff813f59db>] arp_send+0x3b/0x40
  [<ffffffff813f6424>] arp_solicit+0x204/0x280
  [<ffffffff813a1a70>] ? neigh_add+0x310/0x310
  [<ffffffff8139f515>] neigh_probe+0x45/0x70
  [<ffffffff813a1c10>] neigh_timer_handler+0x1a0/0x2a0
  [<ffffffff8104b3cf>] call_timer_fn+0x7f/0x1c0
  [<ffffffff8104b350>] ? detach_if_pending+0x120/0x120
  [<ffffffff8104b748>] run_timer_softirq+0x238/0x2b0
  [<ffffffff813a1a70>] ? neigh_add+0x310/0x310
  [<ffffffff81043e51>] __do_softirq+0x101/0x280
  [<ffffffff814518cc>] call_softirq+0x1c/0x30
  [<ffffffff81003b65>] do_softirq+0x85/0xc0
  [<ffffffff81043a7e>] irq_exit+0x9e/0xc0
  [<ffffffff810264f8>] smp_apic_timer_interrupt+0x68/0xa0
  [<ffffffff8145122f>] apic_timer_interrupt+0x6f/0x80
  <EOI>  [<ffffffff8100a054>] ? mwait_idle+0xa4/0x1c0
  [<ffffffff8100a04b>] ? mwait_idle+0x9b/0x1c0
  [<ffffffff8100a6a9>] cpu_idle+0x89/0xe0
  [<ffffffff81441127>] start_secondary+0x1b2/0x1b6

Bug is from arp_solicit(), releasing the neigh lock after arp_send()
In case of vxlan, we eventually need to write lock a neigh lock later.

Its a false positive, but we can get rid of it without lockdep
annotations.

We can instead use neigh_ha_snapshot() helper.
Reported-by: NYan Burman <yanb@mellanox.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Allow an unpriviled user who has created a user namespace, and then
created a network namespace to effectively use the new network
namespace, by reducing capable(CAP_NET_ADMIN) and
capable(CAP_NET_RAW) calls to be ns_capable(net->user_ns,
CAP_NET_ADMIN), or capable(net->user_ns, CAP_NET_RAW) calls.

Settings that merely control a single network device are allowed.
Either the network device is a logical network device where
restrictions make no difference or the network device is hardware NIC
that has been explicity moved from the initial network namespace.

In general policy and network stack state changes are allowed
while resource control is left unchanged.

Allow creating raw sockets.
Allow the SIOCSARP ioctl to control the arp cache.
Allow the SIOCSIFFLAG ioctl to allow setting network device flags.
Allow the SIOCSIFADDR ioctl to allow setting a netdevice ipv4 address.
Allow the SIOCSIFBRDADDR ioctl to allow setting a netdevice ipv4 broadcast address.
Allow the SIOCSIFDSTADDR ioctl to allow setting a netdevice ipv4 destination address.
Allow the SIOCSIFNETMASK ioctl to allow setting a netdevice ipv4 netmask.
Allow the SIOCADDRT and SIOCDELRT ioctls to allow adding and deleting ipv4 routes.

Allow the SIOCADDTUNNEL, SIOCCHGTUNNEL and SIOCDELTUNNEL ioctls for
adding, changing and deleting gre tunnels.

Allow the SIOCADDTUNNEL, SIOCCHGTUNNEL and SIOCDELTUNNEL ioctls for
adding, changing and deleting ipip tunnels.

Allow the SIOCADDTUNNEL, SIOCCHGTUNNEL and SIOCDELTUNNEL ioctls for
adding, changing and deleting ipsec virtual tunnel interfaces.

Allow setting the MRT_INIT, MRT_DONE, MRT_ADD_VIF, MRT_DEL_VIF, MRT_ADD_MFC,
MRT_DEL_MFC, MRT_ASSERT, MRT_PIM, MRT_TABLE socket options on multicast routing
sockets.

Allow setting and receiving IPOPT_CIPSO, IP_OPT_SEC, IP_OPT_SID and
arbitrary ip options.

Allow setting IP_SEC_POLICY/IP_XFRM_POLICY ipv4 socket option.
Allow setting the IP_TRANSPARENT ipv4 socket option.
Allow setting the TCP_REPAIR socket option.
Allow setting the TCP_CONGESTION socket option.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since route cache deletion (89aef892), delay is no
more used. Remove it.
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since route cache deletion (89aef892), delay is no
more used. Remove it.
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NAlexander Duyck <alexander.duyck@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In order to allow prefixed routes, we have to adjust how rt_gateway
is set and interpreted.

The new interpretation is:

1) rt_gateway == 0, destination is on-link, nexthop is iph->daddr

2) rt_gateway != 0, destination requires a nexthop gateway

Abstract the fetching of the proper nexthop value using a new
inline helper, rt_nexthop(), as suggested by Joe Perches.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Tested-by: NVijay Subramanian <subramanian.vijay@gmail.com>

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: NDavid S. Miller <davem@davemloft.net>

This reverts commit c074da28.

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: NDavid S. Miller <davem@davemloft.net>

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

Routing of 127/8 is tradtionally forbidden, we consider
packets from that address block martian when routing and do
not process corresponding ARP requests.

This is a sane default but renders a huge address space
practically unuseable.

The RFC states that no address within the 127/8 block should
ever appear on any network anywhere but it does not forbid
the use of such addresses outside of the loopback device in
particular. For example to address a pool of virtual guests
behind a load balancer.

This patch adds a new interface option 'route_localnet'
enabling routing of the 127/8 address block and processing
of ARP requests on a specific interface.

Note that for the feature to work, the default local route
covering 127/8 dev lo needs to be removed.

Example:
  $ sysctl -w net.ipv4.conf.eth0.route_localnet=1
  $ ip route del 127.0.0.0/8 dev lo table local
  $ ip addr add 127.1.0.1/16 dev eth0
  $ ip route flush cache

V2: Fix invalid check to auto flush cache (thanks davem)
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use the current debugging style and enable dynamic_debug.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid 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: NPaul Gortmaker <paul.gortmaker@windriver.com>