From: Ido Schimmel <idosch@mellanox.com>
Date: Sat, 14 Dec 2019 17:53:13 +0200
Subject: ipv4: Only Replay routes of interest to new listeners
Patch-mainline: v5.6-rc1
Git-commit: 20d1565203e68cd32d5db3e293e7323173ad7a0d
References: bsc#1176774

When a new listener is registered to the FIB notification chain it
receives a dump of all the available routes in the system. Instead, make
sure to only replay the IPv4 routes that are actually used in the data
path and are of any interest to the new listener.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/ipv4/fib_trie.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -2080,6 +2080,7 @@ static int fib_leaf_notify(struct key_ve
 			   struct netlink_ext_ack *extack)
 {
 	struct fib_alias *fa;
+	int last_slen = -1;
 	int err;
 
 	hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
@@ -2099,6 +2100,16 @@ static int fib_leaf_notify(struct key_ve
 					      fa, extack);
 		if (err)
 			return err;
+
+		if (fa->fa_slen == last_slen)
+			continue;
+
+		last_slen = fa->fa_slen;
+		err = call_fib_entry_notifier(nb, FIB_EVENT_ENTRY_REPLACE_TMP,
+					      l->key, KEYLENGTH - fa->fa_slen,
+					      fa, extack);
+		if (err)
+			return err;
 	}
 	return 0;
 }