Commit 982acb97 authored by Ido Schimmel's avatar Ido Schimmel Committed by David S. Miller
Browse files

ipv4: fib: Notify about nexthop status changes 



When a multipath route is hit the kernel doesn't consider nexthops that
are DEAD or LINKDOWN when IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN is set.
Devices that offload multipath routes need to be made aware of nexthop
status changes. Otherwise, the device will keep forwarding packets to
non-functional nexthops.

Add the FIB_EVENT_NH_{ADD,DEL} events to the fib notification chain,
which notify capable devices when they should add or delete a nexthop
from their tables.

Cc: Roopa Prabhu <roopa@cumulusnetworks.com>
Cc: David Ahern <dsa@cumulusnetworks.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: default avatarIdo Schimmel <idosch@mellanox.com>
Signed-off-by: default avatarJiri Pirko <jiri@mellanox.com>
Reviewed-by: default avatarAndy Gospodarek <gospo@broadcom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 70ad3506

include/net/ip_fib.h

+7 −0
Original line number Diff line number Diff line
@@ -214,11 +214,18 @@ struct fib_entry_notifier_info { 
	u32 nlflags;

};



struct fib_nh_notifier_info {

	struct fib_notifier_info info; /* must be first */

	struct fib_nh *fib_nh;

};



enum fib_event_type {

	FIB_EVENT_ENTRY_ADD,

	FIB_EVENT_ENTRY_DEL,

	FIB_EVENT_RULE_ADD,

	FIB_EVENT_RULE_DEL,

	FIB_EVENT_NH_ADD,

	FIB_EVENT_NH_DEL,

};



int register_fib_notifier(struct notifier_block *nb,

net/ipv4/fib_semantics.c

+33 −0
Original line number Diff line number Diff line
@@ -1355,6 +1355,36 @@ int fib_sync_down_addr(struct net_device *dev, __be32 local) 
	return ret;

}



static int call_fib_nh_notifiers(struct fib_nh *fib_nh,

				 enum fib_event_type event_type)

{

	struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev);

	struct fib_nh_notifier_info info = {

		.fib_nh = fib_nh,

	};



	switch (event_type) {

	case FIB_EVENT_NH_ADD:

		if (fib_nh->nh_flags & RTNH_F_DEAD)

			break;

		if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&

		    fib_nh->nh_flags & RTNH_F_LINKDOWN)

			break;

		return call_fib_notifiers(dev_net(fib_nh->nh_dev), event_type,

					  &info.info);

	case FIB_EVENT_NH_DEL:

		if ((IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&

		     fib_nh->nh_flags & RTNH_F_LINKDOWN) ||

		    (fib_nh->nh_flags & RTNH_F_DEAD))

			return call_fib_notifiers(dev_net(fib_nh->nh_dev),

						  event_type, &info.info);

	default:

		break;

	}



	return NOTIFY_DONE;

}



/* Event              force Flags           Description

 * NETDEV_CHANGE      0     LINKDOWN        Carrier OFF, not for scope host

 * NETDEV_DOWN        0     LINKDOWN|DEAD   Link down, not for scope host
@@ -1396,6 +1426,8 @@ int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) 
					nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;

					break;

				}

				call_fib_nh_notifiers(nexthop_nh,

						      FIB_EVENT_NH_DEL);

				dead++;

			}

#ifdef CONFIG_IP_ROUTE_MULTIPATH
@@ -1550,6 +1582,7 @@ int fib_sync_up(struct net_device *dev, unsigned int nh_flags) 
				continue;

			alive++;

			nexthop_nh->nh_flags &= ~nh_flags;

			call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);

		} endfor_nexthops(fi)



		if (alive > 0) {

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