net: bridge: vlan options: nest the tunnel id into a tunnel info attribute

While discussing the new API, Roopa mentioned that we'll be adding more
tunnel attributes and options in the future, so it's better to make it a
nested attribute, since this is still in net-next we can easily change it
and nest the tunnel id attribute under BRIDGE_VLANDB_ENTRY_TUNNEL_INFO.

The new format is:
[BRIDGE_VLANDB_ENTRY]
[BRIDGE_VLANDB_ENTRY_TUNNEL_INFO]
[BRIDGE_VLANDB_TINFO_ID]

Any new tunnel attributes can be nested under
BRIDGE_VLANDB_ENTRY_TUNNEL_INFO.

Suggested-by: Roopa Prabhu <[e-mail]>
Signed-off-by: Nikolay Aleksandrov <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/uapi/linux/if_bridge.h

···
 	BRIDGE_VLANDB_ENTRY_INFO,
 	BRIDGE_VLANDB_ENTRY_RANGE,
 	BRIDGE_VLANDB_ENTRY_STATE,
-	BRIDGE_VLANDB_ENTRY_TUNNEL_ID,
+	BRIDGE_VLANDB_ENTRY_TUNNEL_INFO,
 	BRIDGE_VLANDB_ENTRY_STATS,
 	__BRIDGE_VLANDB_ENTRY_MAX,
 };
 #define BRIDGE_VLANDB_ENTRY_MAX (__BRIDGE_VLANDB_ENTRY_MAX - 1)
+
+/* [BRIDGE_VLANDB_ENTRY] = {
+ *     [BRIDGE_VLANDB_ENTRY_TUNNEL_INFO] = {
+ *         [BRIDGE_VLANDB_TINFO_ID]
+ *         ...
+ *     }
+ * }
+ */
+enum {
+	BRIDGE_VLANDB_TINFO_UNSPEC,
+	BRIDGE_VLANDB_TINFO_ID,
+	__BRIDGE_VLANDB_TINFO_MAX,
+};
+#define BRIDGE_VLANDB_TINFO_MAX (__BRIDGE_VLANDB_TINFO_MAX - 1)
 
 /* [BRIDGE_VLANDB_ENTRY] = {
  *     [BRIDGE_VLANDB_ENTRY_STATS] = {

net/bridge/br_vlan.c

···
 					    .len = sizeof(struct bridge_vlan_info) },
 	[BRIDGE_VLANDB_ENTRY_RANGE]	= { .type = NLA_U16 },
 	[BRIDGE_VLANDB_ENTRY_STATE]	= { .type = NLA_U8 },
-	[BRIDGE_VLANDB_ENTRY_TUNNEL_ID] = { .type = NLA_U32 },
+	[BRIDGE_VLANDB_ENTRY_TUNNEL_INFO] = { .type = NLA_NESTED },
 };
 
 static int br_vlan_rtm_process_one(struct net_device *dev,

net/bridge/br_vlan_options.c

···
 static bool __vlan_tun_put(struct sk_buff *skb, const struct net_bridge_vlan *v)
 {
 	__be32 tid = tunnel_id_to_key32(v->tinfo.tunnel_id);
+	struct nlattr *nest;
 
 	if (!v->tinfo.tunnel_dst)
 		return true;
 
-	return !nla_put_u32(skb, BRIDGE_VLANDB_ENTRY_TUNNEL_ID,
-			    be32_to_cpu(tid));
+	nest = nla_nest_start(skb, BRIDGE_VLANDB_ENTRY_TUNNEL_INFO);
+	if (!nest)
+		return false;
+	if (nla_put_u32(skb, BRIDGE_VLANDB_TINFO_ID, be32_to_cpu(tid))) {
+		nla_nest_cancel(skb, nest);
+		return false;
+	}
+	nla_nest_end(skb, nest);
+
+	return true;
 }
 
 static bool __vlan_tun_can_enter_range(const struct net_bridge_vlan *v_curr,
···
 size_t br_vlan_opts_nl_size(void)
 {
 	return nla_total_size(sizeof(u8)) /* BRIDGE_VLANDB_ENTRY_STATE */
-	       + nla_total_size(sizeof(u32)); /* BRIDGE_VLANDB_ENTRY_TUNNEL_ID */
+	       + nla_total_size(0) /* BRIDGE_VLANDB_ENTRY_TUNNEL_INFO */
+	       + nla_total_size(sizeof(u32)); /* BRIDGE_VLANDB_TINFO_ID */
 }
 
 static int br_vlan_modify_state(struct net_bridge_vlan_group *vg,
···
 	return 0;
 }
 
+static const struct nla_policy br_vlandb_tinfo_pol[BRIDGE_VLANDB_TINFO_MAX + 1] = {
+	[BRIDGE_VLANDB_TINFO_ID]	= { .type = NLA_U32 },
+};
+
 static int br_vlan_modify_tunnel(const struct net_bridge_port *p,
 				 struct net_bridge_vlan *v,
 				 struct nlattr **tb,
 				 bool *changed,
 				 struct netlink_ext_ack *extack)
 {
+	struct nlattr *tun_tb[BRIDGE_VLANDB_TINFO_MAX + 1], *attr;
 	struct bridge_vlan_info *vinfo;
-	int cmdmap;
+	int cmdmap, err;
 	u32 tun_id;
 
 	if (!p) {
···
 		return -EINVAL;
 	}
 
+	attr = tb[BRIDGE_VLANDB_ENTRY_TUNNEL_INFO];
+	err = nla_parse_nested(tun_tb, BRIDGE_VLANDB_TINFO_MAX, attr,
+			       br_vlandb_tinfo_pol, extack);
+	if (err)
+		return err;
+
+	if (!tun_tb[BRIDGE_VLANDB_TINFO_ID]) {
+		NL_SET_ERR_MSG_MOD(extack, "Missing tunnel id attribute");
+		return -ENOENT;
+	}
 	/* vlan info attribute is guaranteed by br_vlan_rtm_process_one */
 	vinfo = nla_data(tb[BRIDGE_VLANDB_ENTRY_INFO]);
 	cmdmap = vinfo->flags & BRIDGE_VLAN_INFO_REMOVE_TUN ? RTM_DELLINK :
 							      RTM_SETLINK;
 	/* when working on vlan ranges this represents the starting tunnel id */
-	tun_id = nla_get_u32(tb[BRIDGE_VLANDB_ENTRY_TUNNEL_ID]);
+	tun_id = nla_get_u32(tun_tb[BRIDGE_VLANDB_TINFO_ID]);
 	/* tunnel ids are mapped to each vlan in increasing order,
 	 * the starting vlan is in BRIDGE_VLANDB_ENTRY_INFO and v is the
 	 * current vlan, so we compute: tun_id + v - vinfo->vid
···
 		if (err)
 			return err;
 	}
-	if (tb[BRIDGE_VLANDB_ENTRY_TUNNEL_ID]) {
+	if (tb[BRIDGE_VLANDB_ENTRY_TUNNEL_INFO]) {
 		err = br_vlan_modify_tunnel(p, v, tb, changed, extack);
 		if (err)
 			return err;