From: Ido Schimmel <idosch@mellanox.com>
Date: Fri, 7 Feb 2020 19:26:24 +0200
Subject: mlxsw: spectrum_router: Prevent incorrect replacement of local table
 routes
Patch-mainline: v5.6-rc1
Git-commit: 0508ff8934f40b52a78313049b96eec29a46ba49
References: bsc#1176774

The driver uses the same table to represent both the main and local
routing tables. Prevent routes in the main table from replacing routes
in the local table to reflect the fact that the local table is consulted
first during lookup.

Fixes: b6a1d871d37a ("mlxsw: spectrum_router: Start using new IPv4 route notifications")
Fixes: dacad7b34b59 ("mlxsw: spectrum_router: Start using new IPv6 route notifications")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c |   52 +++++++++++++++++-
 1 file changed, 51 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -4844,6 +4844,23 @@ mlxsw_sp_fib_node_entry_unlink(struct ml
 	fib_node->fib_entry = NULL;
 }
 
+static bool mlxsw_sp_fib4_allow_replace(struct mlxsw_sp_fib4_entry *fib4_entry)
+{
+	struct mlxsw_sp_fib_node *fib_node = fib4_entry->common.fib_node;
+	struct mlxsw_sp_fib4_entry *fib4_replaced;
+
+	if (!fib_node->fib_entry)
+		return true;
+
+	fib4_replaced = container_of(fib_node->fib_entry,
+				     struct mlxsw_sp_fib4_entry, common);
+	if (fib4_entry->tb_id == RT_TABLE_MAIN &&
+	    fib4_replaced->tb_id == RT_TABLE_LOCAL)
+		return false;
+
+	return true;
+}
+
 static int
 mlxsw_sp_router_fib4_replace(struct mlxsw_sp *mlxsw_sp,
 			     const struct fib_entry_notifier_info *fen_info)
@@ -4872,6 +4889,12 @@ mlxsw_sp_router_fib4_replace(struct mlxs
 		goto err_fib4_entry_create;
 	}
 
+	if (!mlxsw_sp_fib4_allow_replace(fib4_entry)) {
+		mlxsw_sp_fib4_entry_destroy(mlxsw_sp, fib4_entry);
+		mlxsw_sp_fib_node_put(mlxsw_sp, fib_node);
+		return 0;
+	}
+
 	replaced = fib_node->fib_entry;
 	err = mlxsw_sp_fib_node_entry_link(mlxsw_sp, &fib4_entry->common);
 	if (err) {
@@ -4908,7 +4931,7 @@ static void mlxsw_sp_router_fib4_del(str
 		return;
 
 	fib4_entry = mlxsw_sp_fib4_entry_lookup(mlxsw_sp, fen_info);
-	if (WARN_ON(!fib4_entry))
+	if (!fib4_entry)
 		return;
 	fib_node = fib4_entry->common.fib_node;
 
@@ -5408,6 +5431,27 @@ mlxsw_sp_fib6_entry_lookup(struct mlxsw_
 	return NULL;
 }
 
+static bool mlxsw_sp_fib6_allow_replace(struct mlxsw_sp_fib6_entry *fib6_entry)
+{
+	struct mlxsw_sp_fib_node *fib_node = fib6_entry->common.fib_node;
+	struct mlxsw_sp_fib6_entry *fib6_replaced;
+	struct fib6_info *rt, *rt_replaced;
+
+	if (!fib_node->fib_entry)
+		return true;
+
+	fib6_replaced = container_of(fib_node->fib_entry,
+				     struct mlxsw_sp_fib6_entry,
+				     common);
+	rt = mlxsw_sp_fib6_entry_rt(fib6_entry);
+	rt_replaced = mlxsw_sp_fib6_entry_rt(fib6_replaced);
+	if (rt->fib6_table->tb6_id == RT_TABLE_MAIN &&
+	    rt_replaced->fib6_table->tb6_id == RT_TABLE_LOCAL)
+		return false;
+
+	return true;
+}
+
 static int mlxsw_sp_router_fib6_replace(struct mlxsw_sp *mlxsw_sp,
 					struct fib6_info **rt_arr,
 					unsigned int nrt6)
@@ -5442,6 +5486,12 @@ static int mlxsw_sp_router_fib6_replace(
 		goto err_fib6_entry_create;
 	}
 
+	if (!mlxsw_sp_fib6_allow_replace(fib6_entry)) {
+		mlxsw_sp_fib6_entry_destroy(mlxsw_sp, fib6_entry);
+		mlxsw_sp_fib_node_put(mlxsw_sp, fib_node);
+		return 0;
+	}
+
 	replaced = fib_node->fib_entry;
 	err = mlxsw_sp_fib_node_entry_link(mlxsw_sp, &fib6_entry->common);
 	if (err)