This patch introduces a new sysctl option to make IPv4 Address Scoping
configurable <draft-stewart-tsvwg-sctp-ipv4-00.txt>.

In networking environments where DNAT rules in iptables prerouting
chains convert destination IP's to link-local/private IP addresses,
SCTP connections fail to establish as the INIT chunk is dropped by the
kernel due to address scope match failure.
For example to support overlapping IP addresses (same IP address with
different vlan id) a Layer-5 application listens on link local IP's,
and there is a DNAT rule that maps the destination IP to a link local
IP. Such applications never get the SCTP INIT if the address-scoping
draft is strictly followed.

This sysctl configuration allows SCTP to function in such
unconventional networking environments.

Sysctl options:
0 - Disable IPv4 address scoping draft altogether
1 - Enable IPv4 address scoping (default, current behavior)
2 - Enable address scoping but allow IPv4 private addresses in init/init-ack
3 - Enable address scoping but allow IPv4 link local address in init/init-ack

Signed-off-by: Bhaskar Dutta <bhaskar.dutta@globallogic.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

This patch updates the sysctl documentation concerning the interpretation
of tcp_retries{1,2} and tcp_orphan_retries.

Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add 'autoconf' and 'disable_ipv6' parameters to the IPv6 module.

The first controls if IPv6 addresses are autoconfigured from
prefixes received in Router Advertisements.  The IPv6 loopback
(::1) and link-local addresses are still configured.

The second controls if IPv6 addresses are desired at all.  No
IPv6 addresses will be added to any interfaces.

Signed-off-by: Brian Haley <brian.haley@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Conflicts:
	drivers/scsi/fcoe/fcoe.c

Signed-off-by: Wang Tinggong <wangtinggong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This should be very safe compared with full enabled, so I see
no reason why it shouldn't be done right away. As ECN can only
be negotiated if the SYN sending party is also supporting it,
somebody in the loop probably knows what he/she is doing. If
SYN does not ask for ECN, the server side SYN-ACK is identical
to what it is without ECN. Thus it's quite safe.

The chosen value is safe w.r.t to existing configs which
choose to currently set manually either 0 or 1 but
silently upgrades those who have not explicitly requested
ECN off.

Whether to just enable both sides comes up time to time but
unless that gets done now we can at least make the servers
aware of ECN already. As there are some known problems to occur
if ECN is enabled, it's currently questionable whether there's
any real gain from enabling clients as servers mostly won't
support it anyway (so we'd hit just the negative sides). After
enabling the servers and getting that deployed, the client end
enable really has some potential gain too.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fix the behavior of allowing both sysctl and addrconf_dad_failure()
to set the disable_ipv6 parameter without any bad side-effects.
If DAD fails and accept_dad > 1, we will still set disable_ipv6=1,
but then instead of allowing an RA to add an address then
immediately fail DAD, we simply don't allow the address to be
added in the first place.  This also lets the user set this flag
and disable all IPv6 addresses on the interface, or on the entire
system.

Signed-off-by: Brian Haley <brian.haley@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fix up whitespaces while going though ip-sysctl.txt anyway.

Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>

First fix a typo in Stephens patch ;-)

Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>

Extend existing reverse path filter option to allow strict or loose
filtering. (See http://en.wikipedia.org/wiki/Reverse_path_filtering).

For compatibility with existing usage, the value 1 is chosen for strict mode
and 2 for loose mode.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>