tmp_suning_uos_patched/net
Andy Gospodarek 0eeb075fad net: ipv4 sysctl option to ignore routes when nexthop link is down
This feature is only enabled with the new per-interface or ipv4 global
sysctls called 'ignore_routes_with_linkdown'.

net.ipv4.conf.all.ignore_routes_with_linkdown = 0
net.ipv4.conf.default.ignore_routes_with_linkdown = 0
net.ipv4.conf.lo.ignore_routes_with_linkdown = 0
...

When the above sysctls are set, will report to userspace that a route is
dead and will no longer resolve to this nexthop when performing a fib
lookup.  This will signal to userspace that the route will not be
selected.  The signalling of a RTNH_F_DEAD is only passed to userspace
if the sysctl is enabled and link is down.  This was done as without it
the netlink listeners would have no idea whether or not a nexthop would
be selected.   The kernel only sets RTNH_F_DEAD internally if the
interface has IFF_UP cleared.

With the new sysctl set, the following behavior can be observed
(interface p8p1 is link-down):

default via 10.0.5.2 dev p9p1
10.0.5.0/24 dev p9p1  proto kernel  scope link  src 10.0.5.15
70.0.0.0/24 dev p7p1  proto kernel  scope link  src 70.0.0.1
80.0.0.0/24 dev p8p1  proto kernel  scope link  src 80.0.0.1 dead linkdown
90.0.0.0/24 via 80.0.0.2 dev p8p1  metric 1 dead linkdown
90.0.0.0/24 via 70.0.0.2 dev p7p1  metric 2
90.0.0.1 via 70.0.0.2 dev p7p1  src 70.0.0.1
    cache
local 80.0.0.1 dev lo  src 80.0.0.1
    cache <local>
80.0.0.2 via 10.0.5.2 dev p9p1  src 10.0.5.15
    cache

While the route does remain in the table (so it can be modified if
needed rather than being wiped away as it would be if IFF_UP was
cleared), the proper next-hop is chosen automatically when the link is
down.  Now interface p8p1 is linked-up:

default via 10.0.5.2 dev p9p1
10.0.5.0/24 dev p9p1  proto kernel  scope link  src 10.0.5.15
70.0.0.0/24 dev p7p1  proto kernel  scope link  src 70.0.0.1
80.0.0.0/24 dev p8p1  proto kernel  scope link  src 80.0.0.1
90.0.0.0/24 via 80.0.0.2 dev p8p1  metric 1
90.0.0.0/24 via 70.0.0.2 dev p7p1  metric 2
192.168.56.0/24 dev p2p1  proto kernel  scope link  src 192.168.56.2
90.0.0.1 via 80.0.0.2 dev p8p1  src 80.0.0.1
    cache
local 80.0.0.1 dev lo  src 80.0.0.1
    cache <local>
80.0.0.2 dev p8p1  src 80.0.0.1
    cache

and the output changes to what one would expect.

If the sysctl is not set, the following output would be expected when
p8p1 is down:

default via 10.0.5.2 dev p9p1
10.0.5.0/24 dev p9p1  proto kernel  scope link  src 10.0.5.15
70.0.0.0/24 dev p7p1  proto kernel  scope link  src 70.0.0.1
80.0.0.0/24 dev p8p1  proto kernel  scope link  src 80.0.0.1 linkdown
90.0.0.0/24 via 80.0.0.2 dev p8p1  metric 1 linkdown
90.0.0.0/24 via 70.0.0.2 dev p7p1  metric 2

Since the dead flag does not appear, there should be no expectation that
the kernel would skip using this route due to link being down.

v2: Split kernel changes into 2 patches, this actually makes a
behavioral change if the sysctl is set.  Also took suggestion from Alex
to simplify code by only checking sysctl during fib lookup and
suggestion from Scott to add a per-interface sysctl.

v3: Code clean-ups to make it more readable and efficient as well as a
reverse path check fix.

v4: Drop binary sysctl

v5: Whitespace fixups from Dave

v6: Style changes from Dave and checkpatch suggestions

v7: One more checkpatch fixup

Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com>
Signed-off-by: Dinesh Dutt <ddutt@cumulusnetworks.com>
Acked-by: Scott Feldman <sfeldma@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-24 02:15:54 -07:00
..
6lowpan 6lowpan: nhc: add other known rfc6282 compressions 2015-02-14 23:08:44 +01:00
9p 9p: patches for 4.1 merge window 2015-04-18 17:45:30 -04:00
802 net: Kill dev_rebuild_header 2015-03-02 16:43:41 -05:00
8021q vlan: Add GRO support for non hardware accelerated vlan 2015-06-01 16:50:52 -07:00
appletalk net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
atm net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
ax25 netfilter: Remove spurios included of netfilter.h 2015-06-18 21:14:32 +02:00
batman-adv batman-adv: change the MAC of each VLAN upon ndo_set_mac_address 2015-06-07 17:07:20 +02:00
bluetooth Bluetooth: Fix warning of potentially uninitialized adv_instance variable 2015-06-18 21:05:31 +03:00
bridge switchdev: rename vlan vid_start to vid_begin 2015-06-23 06:56:18 -07:00
caif Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-01 22:51:30 -07:00
can can: cangw: introduce optional uid to reference created routing jobs 2015-06-09 09:39:49 +02:00
ceph Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-01 22:51:30 -07:00
core switchdev; add VLAN support for port's bridge_getlink 2015-06-23 06:56:18 -07:00
dcb net/dcb: Add IEEE QCN attribute 2015-03-06 21:50:02 -05:00
dccp sock_diag: specify info_size per inet protocol 2015-06-15 19:49:22 -07:00
decnet net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
dns_resolver
dsa Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-01 22:51:30 -07:00
ethernet net: Add full IPv6 addresses to flow_keys 2015-06-04 15:44:30 -07:00
hsr net/hsr: Fix NULL pointer dereference and refcnt bugs when deleting a HSR interface. 2015-03-01 13:40:23 -05:00
ieee802154 nl802154: export supported commands 2015-06-04 12:27:15 +02:00
ipv4 net: ipv4 sysctl option to ignore routes when nexthop link is down 2015-06-24 02:15:54 -07:00
ipv6 netfilter: don't pull include/linux/netfilter.h from netns headers 2015-06-18 21:14:31 +02:00
ipx net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
irda irda: use msecs_to_jiffies for conversion to jiffies 2015-05-25 17:46:21 -04:00
iucv net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
key net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
l2tp net: Modify sk_alloc to not reference count the netns of kernel sockets. 2015-05-11 10:50:18 -04:00
lapb
llc net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
mac80211 mac80211: convert HW flags to unsigned long bitmap 2015-06-10 16:05:36 +02:00
mac802154 mac802154: iface: cleanup stack variable 2015-06-17 16:00:40 +02:00
mpls Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-13 23:56:52 -07:00
netfilter netfilter: nf_qeueue: Drop queue entries on nf_unregister_hook 2015-06-23 06:23:23 -07:00
netlabel netlink: implement nla_put_in_addr and nla_put_in6_addr 2015-03-31 13:58:35 -04:00
netlink netlink: add API to retrieve all group memberships 2015-06-21 10:18:18 -07:00
netrom netfilter: Remove spurios included of netfilter.h 2015-06-18 21:14:32 +02:00
nfc NFC: nci: fix mistake in uart generic driver 2015-06-15 18:10:37 +02:00
openvswitch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-08 20:06:56 -07:00
packet packet: remove handling of tx_ring 2015-06-23 06:53:29 -07:00
phonet net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
rds net: rds: use for_each_sg() for scatterlist parsing 2015-06-21 09:32:08 -07:00
rfkill net: rfkill: gpio: make better use of gpiod API 2015-05-29 13:13:45 +02:00
rose netfilter: Remove spurios included of netfilter.h 2015-06-18 21:14:32 +02:00
rxrpc net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
sched pkt_sched: sch_qfq: remove redundant -if- control statement 2015-06-21 09:47:24 -07:00
sctp Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-13 23:56:52 -07:00
sunrpc svcrpc: fix potential GSSX_ACCEPT_SEC_CONTEXT decoding failures 2015-05-04 12:02:40 -04:00
switchdev net: switchdev: ignore unsupported bridge flags 2015-06-24 01:06:34 -07:00
tipc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-13 23:56:52 -07:00
unix net/unix: support SCM_SECURITY for stream sockets 2015-06-10 22:49:20 -07:00
vmw_vsock net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
wimax
wireless Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-13 23:56:52 -07:00
x25 net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
xfrm Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-01 22:51:30 -07:00
compat.c net: switch importing msghdr from userland to {compat_,}import_iovec() 2015-04-09 00:02:26 -04:00
Kconfig net: add CONFIG_NET_INGRESS to enable ingress filtering 2015-05-14 01:10:05 -04:00
Makefile mpls: Refactor how the mpls module is built 2015-03-04 00:26:06 -05:00
socket.c net: Add a struct net parameter to sock_create_kern 2015-05-11 10:50:17 -04:00
sysctl_net.c