mlxsw: spectrum_router: Add support for nexthop group consolidation for IPv6

Due to limited ASIC resources the maximum number of routes is limited by
the nexthop resource. In order to improve the routing scale nexthop
consolidation should be performed.

This patch adds support for IPv6 neighbor consolidation. The hash value
is calculated based on the nexthop set, by performing bitwise xor on the
ifindexs of the nexthops, in a similar way to IPv4's kernel implementation.
In case of collision a full match is performed between the sets which
include address and ifindex comparison.

Non gateway nexthop groups are not inserted to the hash table due to
lack of nexthop device (ifindex).
Signed-off-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

@@ -1509,6 +1509,7 @@ struct mlxsw_sp_nexthop {
 	struct rhash_head ht_node;
 	struct mlxsw_sp_nexthop_key key;
 	unsigned char gw_addr[sizeof(struct in6_addr)];
+	int ifindex;
 	struct mlxsw_sp_rif *rif;
 	u8 should_offload:1, /* set indicates this neigh is connected and
 			      * should be put to KVD linear area of this group.
@@ -1543,24 +1544,115 @@ mlxsw_sp_nexthop4_group_fi(const struct mlxsw_sp_nexthop_group *nh_grp)
 }
 
 struct mlxsw_sp_nexthop_group_cmp_arg {
-	struct fib_info *fi;
+	enum mlxsw_sp_l3proto proto;
+	union {
+		struct fib_info *fi;
+		struct mlxsw_sp_fib6_entry *fib6_entry;
+	};
 };
 
+static bool
+mlxsw_sp_nexthop6_group_has_nexthop(const struct mlxsw_sp_nexthop_group *nh_grp,
+				    const struct in6_addr *gw, int ifindex)
+{
+	int i;
+
+	for (i = 0; i < nh_grp->count; i++) {
+		const struct mlxsw_sp_nexthop *nh;
+
+		nh = &nh_grp->nexthops[i];
+		if (nh->ifindex == ifindex &&
+		    ipv6_addr_equal(gw, (struct in6_addr *) nh->gw_addr))
+			return true;
+	}
+
+	return false;
+}
+
+static bool
+mlxsw_sp_nexthop6_group_cmp(const struct mlxsw_sp_nexthop_group *nh_grp,
+			    const struct mlxsw_sp_fib6_entry *fib6_entry)
+{
+	struct mlxsw_sp_rt6 *mlxsw_sp_rt6;
+
+	if (nh_grp->count != fib6_entry->nrt6)
+		return false;
+
+	list_for_each_entry(mlxsw_sp_rt6, &fib6_entry->rt6_list, list) {
+		struct in6_addr *gw;
+		int ifindex;
+
+		ifindex = mlxsw_sp_rt6->rt->dst.dev->ifindex;
+		gw = &mlxsw_sp_rt6->rt->rt6i_gateway;
+		if (!mlxsw_sp_nexthop6_group_has_nexthop(nh_grp, gw, ifindex))
+			return false;
+	}
+
+	return true;
+}
+
 static int
 mlxsw_sp_nexthop_group_cmp(struct rhashtable_compare_arg *arg, const void *ptr)
 {
 	const struct mlxsw_sp_nexthop_group_cmp_arg *cmp_arg = arg->key;
 	const struct mlxsw_sp_nexthop_group *nh_grp = ptr;
 
-	return cmp_arg->fi != mlxsw_sp_nexthop4_group_fi(nh_grp);
+	switch (cmp_arg->proto) {
+	case MLXSW_SP_L3_PROTO_IPV4:
+		return cmp_arg->fi != mlxsw_sp_nexthop4_group_fi(nh_grp);
+	case MLXSW_SP_L3_PROTO_IPV6:
+		return !mlxsw_sp_nexthop6_group_cmp(nh_grp,
+						    cmp_arg->fib6_entry);
+	default:
+		WARN_ON(1);
+		return 1;
+	}
+}
+
+static int
+mlxsw_sp_nexthop_group_type(const struct mlxsw_sp_nexthop_group *nh_grp)
+{
+	return nh_grp->neigh_tbl->family;
 }
 
 static u32 mlxsw_sp_nexthop_group_hash_obj(const void *data, u32 len, u32 seed)
 {
 	const struct mlxsw_sp_nexthop_group *nh_grp = data;
-	struct fib_info *fi = mlxsw_sp_nexthop4_group_fi(nh_grp);
+	const struct mlxsw_sp_nexthop *nh;
+	struct fib_info *fi;
+	unsigned int val;
+	int i;
+
+	switch (mlxsw_sp_nexthop_group_type(nh_grp)) {
+	case AF_INET:
+		fi = mlxsw_sp_nexthop4_group_fi(nh_grp);
+		return jhash(&fi, sizeof(fi), seed);
+	case AF_INET6:
+		val = nh_grp->count;
+		for (i = 0; i < nh_grp->count; i++) {
+			nh = &nh_grp->nexthops[i];
+			val ^= nh->ifindex;
+		}
+		return jhash(&val, sizeof(val), seed);
+	default:
+		WARN_ON(1);
+		return 0;
+	}
+}
+
+static u32
+mlxsw_sp_nexthop6_group_hash(struct mlxsw_sp_fib6_entry *fib6_entry, u32 seed)
+{
+	unsigned int val = fib6_entry->nrt6;
+	struct mlxsw_sp_rt6 *mlxsw_sp_rt6;
+	struct net_device *dev;
+
+	list_for_each_entry(mlxsw_sp_rt6, &fib6_entry->rt6_list, list) {
+		dev = mlxsw_sp_rt6->rt->dst.dev;
+		val ^= dev->ifindex;
+	}
 
-	return jhash(&fi, sizeof(fi), seed);
+	return jhash(&val, sizeof(val), seed);
 }
 
 static u32
@@ -1568,7 +1660,15 @@ mlxsw_sp_nexthop_group_hash(const void *data, u32 len, u32 seed)
 {
 	const struct mlxsw_sp_nexthop_group_cmp_arg *cmp_arg = data;
 
-	return jhash(&cmp_arg->fi, sizeof(cmp_arg->fi), seed);
+	switch (cmp_arg->proto) {
+	case MLXSW_SP_L3_PROTO_IPV4:
+		return jhash(&cmp_arg->fi, sizeof(cmp_arg->fi), seed);
+	case MLXSW_SP_L3_PROTO_IPV6:
+		return mlxsw_sp_nexthop6_group_hash(cmp_arg->fib6_entry, seed);
+	default:
+		WARN_ON(1);
+		return 0;
+	}
 }
 
 static const struct rhashtable_params mlxsw_sp_nexthop_group_ht_params = {
@@ -1581,6 +1681,10 @@ static const struct rhashtable_params mlxsw_sp_nexthop_group_ht_params = {
 static int mlxsw_sp_nexthop_group_insert(struct mlxsw_sp *mlxsw_sp,
 					 struct mlxsw_sp_nexthop_group *nh_grp)
 {
+	if (mlxsw_sp_nexthop_group_type(nh_grp) == AF_INET6 &&
+	    !nh_grp->gateway)
+		return 0;
+
 	return rhashtable_insert_fast(&mlxsw_sp->router->nexthop_group_ht,
 				      &nh_grp->ht_node,
 				      mlxsw_sp_nexthop_group_ht_params);
@@ -1589,6 +1693,10 @@ static int mlxsw_sp_nexthop_group_insert(struct mlxsw_sp *mlxsw_sp,
 static void mlxsw_sp_nexthop_group_remove(struct mlxsw_sp *mlxsw_sp,
 					  struct mlxsw_sp_nexthop_group *nh_grp)
 {
+	if (mlxsw_sp_nexthop_group_type(nh_grp) == AF_INET6 &&
+	    !nh_grp->gateway)
+		return;
+
 	rhashtable_remove_fast(&mlxsw_sp->router->nexthop_group_ht,
 			       &nh_grp->ht_node,
 			       mlxsw_sp_nexthop_group_ht_params);
@@ -1600,12 +1708,26 @@ mlxsw_sp_nexthop4_group_lookup(struct mlxsw_sp *mlxsw_sp,
 {
 	struct mlxsw_sp_nexthop_group_cmp_arg cmp_arg;
 
+	cmp_arg.proto = MLXSW_SP_L3_PROTO_IPV4;
 	cmp_arg.fi = fi;
 	return rhashtable_lookup_fast(&mlxsw_sp->router->nexthop_group_ht,
 				      &cmp_arg,
 				      mlxsw_sp_nexthop_group_ht_params);
 }
 
+static struct mlxsw_sp_nexthop_group *
+mlxsw_sp_nexthop6_group_lookup(struct mlxsw_sp *mlxsw_sp,
+			       struct mlxsw_sp_fib6_entry *fib6_entry)
+{
+	struct mlxsw_sp_nexthop_group_cmp_arg cmp_arg;
+
+	cmp_arg.proto = MLXSW_SP_L3_PROTO_IPV6;
+	cmp_arg.fib6_entry = fib6_entry;
+	return rhashtable_lookup_fast(&mlxsw_sp->router->nexthop_group_ht,
+				      &cmp_arg,
+				      mlxsw_sp_nexthop_group_ht_params);
+}
+
 static const struct rhashtable_params mlxsw_sp_nexthop_ht_params = {
 	.key_offset = offsetof(struct mlxsw_sp_nexthop, key),
 	.head_offset = offsetof(struct mlxsw_sp_nexthop, ht_node),
@@ -3197,6 +3319,7 @@ static int mlxsw_sp_nexthop6_init(struct mlxsw_sp *mlxsw_sp,
 
 	if (!dev)
 		return 0;
+	nh->ifindex = dev->ifindex;
 
 	rif = mlxsw_sp_rif_find_by_dev(mlxsw_sp, dev);
 	if (!rif)
@@ -3254,9 +3377,15 @@ mlxsw_sp_nexthop6_group_create(struct mlxsw_sp *mlxsw_sp,
 			goto err_nexthop6_init;
 		mlxsw_sp_rt6 = list_next_entry(mlxsw_sp_rt6, list);
 	}
+
+	err = mlxsw_sp_nexthop_group_insert(mlxsw_sp, nh_grp);
+	if (err)
+		goto err_nexthop_group_insert;
+
 	mlxsw_sp_nexthop_group_refresh(mlxsw_sp, nh_grp);
 	return nh_grp;
 
+err_nexthop_group_insert:
 err_nexthop6_init:
 	for (i--; i >= 0; i--) {
 		nh = &nh_grp->nexthops[i];
@@ -3273,6 +3402,7 @@ mlxsw_sp_nexthop6_group_destroy(struct mlxsw_sp *mlxsw_sp,
 	struct mlxsw_sp_nexthop *nh;
 	int i = nh_grp->count;
 
+	mlxsw_sp_nexthop_group_remove(mlxsw_sp, nh_grp);
 	for (i--; i >= 0; i--) {
 		nh = &nh_grp->nexthops[i];
 		mlxsw_sp_nexthop6_fini(mlxsw_sp, nh);
@@ -3287,10 +3417,12 @@ static int mlxsw_sp_nexthop6_group_get(struct mlxsw_sp *mlxsw_sp,
 {
 	struct mlxsw_sp_nexthop_group *nh_grp;
 
-	/* For now, don't consolidate nexthop groups */
-	nh_grp = mlxsw_sp_nexthop6_group_create(mlxsw_sp, fib6_entry);
-	if (IS_ERR(nh_grp))
-		return PTR_ERR(nh_grp);
+	nh_grp = mlxsw_sp_nexthop6_group_lookup(mlxsw_sp, fib6_entry);
+	if (!nh_grp) {
+		nh_grp = mlxsw_sp_nexthop6_group_create(mlxsw_sp, fib6_entry);
+		if (IS_ERR(nh_grp))
+			return PTR_ERR(nh_grp);
+	}
 
 	list_add_tail(&fib6_entry->common.nexthop_group_node,
 		      &nh_grp->fib_list);