fib: hook IPv4 fib for hardware offload

Call into the switchdev driver any time an IPv4 fib entry is
added/modified/deleted from the kernel's FIB.  The switchdev driver may or
may not install the route to the offload device.  In the case where the
driver tries to install the route and something goes wrong (device's routing
table is full, etc), then all of the offloaded routes will be flushed from the
device, route forwarding falls back to the kernel, and no more routes are
offloading.

We can refine this logic later.  For now, use the simplist model of offloading
routes up to the point of failure, and then on failure, undo everything and
mark IPv4 offloading disabled.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/net/switchdev.h b/include/net/switchdev.h
index 8d2ac663325a..dc0a5cc7c2c5 100644
--- a/include/net/switchdev.h
+++ b/include/net/switchdev.h
@@ -55,6 +55,7 @@ int netdev_switch_fib_ipv4_add(u32 dst, int dst_len, struct fib_info *fi,
                                u8 tos, u8 type, u32 tb_id);
 int netdev_switch_fib_ipv4_del(u32 dst, int dst_len, struct fib_info *fi,
                                u8 tos, u8 type, u32 tb_id);
+void netdev_switch_fib_ipv4_abort(struct fib_info *fi);
 
 #else
 
@@ -128,6 +129,10 @@ static inline int netdev_switch_fib_ipv4_del(u32 dst, int dst_len,
         return 0;
 }
 
+void netdev_switch_fib_ipv4_abort(struct fib_info *fi)
+{
+}
+
 #endif
 
 #endif /* _LINUX_SWITCHDEV_H_ */