net: bridge: vlan options: add support for tunnel mapping set/del

This patch adds support for manipulating vlan/tunnel mappings. The
tunnel ids are globally unique and are one per-vlan. There were two
trickier issues - first in order to support vlan ranges we have to
compute the current tunnel id in the following way:
 - base tunnel id (attr) + current vlan id - starting vlan id
This is in line how the old API does vlan/tunnel mapping with ranges. We
already have the vlan range present, so it's redundant to add another
attribute for the tunnel range end. It's simply base tunnel id + vlan
range. And second to support removing mappings we need an out-of-band way
to tell the option manipulating function because there are no
special/reserved tunnel id values, so we use a vlan flag to denote the
operation is tunnel mapping removal.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 39 insertions, 0 deletions

diff --git a/net/bridge/br_vlan_options.c b/net/bridge/br_vlan_options.c
index d3618da32b8e..138e180cf4d8 100644
--- a/net/bridge/br_vlan_options.c
+++ b/net/bridge/br_vlan_options.c
@@ -85,6 +85,40 @@ static int br_vlan_modify_state(struct net_bridge_vlan_group *vg,
 	return 0;
 }
 
+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 bridge_vlan_info *vinfo;
+	int cmdmap;
+	u32 tun_id;
+
+	if (!p) {
+		NL_SET_ERR_MSG_MOD(extack, "Can't modify tunnel mapping of non-port vlans");
+		return -EINVAL;
+	}
+	if (!(p->flags & BR_VLAN_TUNNEL)) {
+		NL_SET_ERR_MSG_MOD(extack, "Port doesn't have tunnel flag set");
+		return -EINVAL;
+	}
+
+	/* 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]);
+	/* 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
+	 */
+	tun_id += v->vid - vinfo->vid;
+
+	return br_vlan_tunnel_info(p, cmdmap, v->vid, tun_id, changed);
+}
+
 static int br_vlan_process_one_opts(const struct net_bridge *br,
 				    const struct net_bridge_port *p,
 				    struct net_bridge_vlan_group *vg,
@@ -103,6 +137,11 @@ static int br_vlan_process_one_opts(const struct net_bridge *br,
 		if (err)
 			return err;
 	}
+	if (tb[BRIDGE_VLANDB_ENTRY_TUNNEL_ID]) {
+		err = br_vlan_modify_tunnel(p, v, tb, changed, extack);
+		if (err)
+			return err;
+	}
 
 	return 0;
 }