Merge branch 'nexthop-add-support-for-nexthop-objects-offload'

Ido Schimmel says:

====================
nexthop: Add support for nexthop objects offload

This patch set adds support for nexthop objects offload with a dummy
implementation over netdevsim. mlxsw support will be added later.

The general idea is very similar to route offload in that notifications
are sent whenever nexthop objects are changed. A listener can veto the
change and the error will be communicated to user space with extack.

To keep listeners as simple as possible, they not only receive
notifications for the nexthop object that is changed, but also for all
the other objects affected by this change. For example, when a single
nexthop is replaced, a replace notification is sent for the single
nexthop, but also for all the nexthop groups this nexthop is member in.
This relieves listeners from the need to track such dependencies.

To simplify things further for listeners, the notification info does not
contain the raw nexthop data structures (e.g., 'struct nexthop'), but
less complex data structures into which the raw data structures are
parsed into.

Tested with a new selftest over netdevsim and with fib_nexthops.sh:

Tests passed: 164
Tests failed:   0

Patch set overview:

Patches #1-#4 introduce the aforementioned data structures and convert
existing listeners (i.e., the VXLAN driver) to use them.

Patches #5-#6 add a new RTNH_F_TRAP flag and the ability to set it and
RTNH_F_OFFLOAD on nexthops. This flag is used by netdevsim for testing
purposes and will also be used by mlxsw. These flags are consistent with
the existing RTM_F_OFFLOAD and RTM_F_TRAP flags.

Patches #7-#14 gradually add the new nexthop notifications.

Patches #15-#18 add a dummy implementation for nexthop offload over
netdevsim and a selftest to exercise both good and bad flows.

Changes since RFC [1]:

Patch #1: s/is_encap/has_encap/
Patch #3: Add a blank line in __nh_notifier_single_info_init()
Patch #5: Reword commit message
Patch #6: s/nexthop_hw_flags_set/nexthop_set_hw_flags/
Patch #7: Reword commit message
Patch #11: Allocate extack on the stack

Follow-up patch sets:

selftests: forwarding: Add nexthop objects tests
mlxsw: Preparations for nexthop objects support - part 1/2
mlxsw: Preparations for nexthop objects support - part 2/2
mlxsw: Add support for nexthop objects
mlxsw: Add support for blackhole nexthops
mlxsw: Update adjacency index more efficiently

[1] https://lore.kernel.org/netdev/20200908091037.2709823-1-idosch@idosch.org/
====================

Link: https://lore.kernel.org/r/20201104133040.1125369-1-idosch@idosch.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 40 insertions, 2 deletions

diff --git a/include/net/nexthop.h b/include/net/nexthop.h
index 2fd76a9b6dc8..226930d66b63 100644
--- a/include/net/nexthop.h
+++ b/include/net/nexthop.h
@@ -105,11 +105,49 @@ struct nexthop {
 };
 
 enum nexthop_event_type {
-	NEXTHOP_EVENT_DEL
+	NEXTHOP_EVENT_DEL,
+	NEXTHOP_EVENT_REPLACE,
 };
 
-int register_nexthop_notifier(struct net *net, struct notifier_block *nb);
+struct nh_notifier_single_info {
+	struct net_device *dev;
+	u8 gw_family;
+	union {
+		__be32 ipv4;
+		struct in6_addr ipv6;
+	};
+	u8 is_reject:1,
+	   is_fdb:1,
+	   has_encap:1;
+};
+
+struct nh_notifier_grp_entry_info {
+	u8 weight;
+	u32 id;
+	struct nh_notifier_single_info nh;
+};
+
+struct nh_notifier_grp_info {
+	u16 num_nh;
+	bool is_fdb;
+	struct nh_notifier_grp_entry_info nh_entries[];
+};
+
+struct nh_notifier_info {
+	struct net *net;
+	struct netlink_ext_ack *extack;
+	u32 id;
+	bool is_grp;
+	union {
+		struct nh_notifier_single_info *nh;
+		struct nh_notifier_grp_info *nh_grp;
+	};
+};
+
+int register_nexthop_notifier(struct net *net, struct notifier_block *nb,
+			      struct netlink_ext_ack *extack);
 int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb);
+void nexthop_set_hw_flags(struct net *net, u32 id, bool offload, bool trap);
 
 /* caller is holding rcu or rtnl; no reference taken to nexthop */
 struct nexthop *nexthop_find_by_id(struct net *net, u32 id);