openvswitch: reliable interface indentification in port dumps

This patch allows reliable identification of netdevice interfaces connected
to openvswitch bridges. In particular, user space queries the netdev
interfaces belonging to the ports for statistics, up/down state, etc.
Datapath dump needs to provide enough information for the user space to be
able to do that.

Currently, only interface names are returned. This is not sufficient, as
openvswitch allows its ports to be in different name spaces and the
interface name is valid only in its name space. What is needed and generally
used in other netlink APIs, is the pair ifindex+netnsid.

The solution is addition of the ifindex+netnsid pair (or only ifindex if in
the same name space) to vport get/dump operation.

On request side, ideally the ifindex+netnsid pair could be used to
get/set/del the corresponding vport. This is not implemented by this patch
and can be added later if needed.
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/openvswitch.h

@@ -258,6 +258,8 @@ enum ovs_vport_attr {
 				/* receiving upcalls */
 	OVS_VPORT_ATTR_STATS,	/* struct ovs_vport_stats */
 	OVS_VPORT_ATTR_PAD,
+	OVS_VPORT_ATTR_IFINDEX,
+	OVS_VPORT_ATTR_NETNSID,
 	__OVS_VPORT_ATTR_MAX
 };
 

net/openvswitch/datapath.c

@@ -1848,7 +1848,8 @@ static struct genl_family dp_datapath_genl_family __ro_after_init = {
 
 /* Called with ovs_mutex or RCU read lock. */
 static int ovs_vport_cmd_fill_info(struct vport *vport, struct sk_buff *skb,
-				   u32 portid, u32 seq, u32 flags, u8 cmd)
+				   struct net *net, u32 portid, u32 seq,
+				   u32 flags, u8 cmd)
 {
 	struct ovs_header *ovs_header;
 	struct ovs_vport_stats vport_stats;
@@ -1864,9 +1865,17 @@ static int ovs_vport_cmd_fill_info(struct vport *vport, struct sk_buff *skb,
 	if (nla_put_u32(skb, OVS_VPORT_ATTR_PORT_NO, vport->port_no) ||
 	    nla_put_u32(skb, OVS_VPORT_ATTR_TYPE, vport->ops->type) ||
 	    nla_put_string(skb, OVS_VPORT_ATTR_NAME,
-			   ovs_vport_name(vport)))
+			   ovs_vport_name(vport)) ||
+	    nla_put_u32(skb, OVS_VPORT_ATTR_IFINDEX, vport->dev->ifindex))
 		goto nla_put_failure;
 
+	if (!net_eq(net, dev_net(vport->dev))) {
+		int id = peernet2id_alloc(net, dev_net(vport->dev));
+
+		if (nla_put_s32(skb, OVS_VPORT_ATTR_NETNSID, id))
+			goto nla_put_failure;
+	}
+
 	ovs_vport_get_stats(vport, &vport_stats);
 	if (nla_put_64bit(skb, OVS_VPORT_ATTR_STATS,
 			  sizeof(struct ovs_vport_stats), &vport_stats,
@@ -1896,8 +1905,8 @@ static struct sk_buff *ovs_vport_cmd_alloc_info(void)
 }
 
 /* Called with ovs_mutex, only via ovs_dp_notify_wq(). */
-struct sk_buff *ovs_vport_cmd_build_info(struct vport *vport, u32 portid,
-					 u32 seq, u8 cmd)
+struct sk_buff *ovs_vport_cmd_build_info(struct vport *vport, struct net *net,
+					 u32 portid, u32 seq, u8 cmd)
 {
 	struct sk_buff *skb;
 	int retval;
@@ -1906,7 +1915,7 @@ struct sk_buff *ovs_vport_cmd_build_info(struct vport *vport, u32 portid,
 	if (!skb)
 		return ERR_PTR(-ENOMEM);
 
-	retval = ovs_vport_cmd_fill_info(vport, skb, portid, seq, 0, cmd);
+	retval = ovs_vport_cmd_fill_info(vport, skb, net, portid, seq, 0, cmd);
 	BUG_ON(retval < 0);
 
 	return skb;
@@ -1920,6 +1929,8 @@ static struct vport *lookup_vport(struct net *net,
 	struct datapath *dp;
 	struct vport *vport;
 
+	if (a[OVS_VPORT_ATTR_IFINDEX])
+		return ERR_PTR(-EOPNOTSUPP);
 	if (a[OVS_VPORT_ATTR_NAME]) {
 		vport = ovs_vport_locate(net, nla_data(a[OVS_VPORT_ATTR_NAME]));
 		if (!vport)
@@ -1944,6 +1955,7 @@ static struct vport *lookup_vport(struct net *net,
 		return vport;
 	} else
 		return ERR_PTR(-EINVAL);
+
 }
 
 /* Called with ovs_mutex */
@@ -1983,6 +1995,8 @@ static int ovs_vport_cmd_new(struct sk_buff *skb, struct genl_info *info)
 	if (!a[OVS_VPORT_ATTR_NAME] || !a[OVS_VPORT_ATTR_TYPE] ||
 	    !a[OVS_VPORT_ATTR_UPCALL_PID])
 		return -EINVAL;
+	if (a[OVS_VPORT_ATTR_IFINDEX])
+		return -EOPNOTSUPP;
 
 	port_no = a[OVS_VPORT_ATTR_PORT_NO]
 		? nla_get_u32(a[OVS_VPORT_ATTR_PORT_NO]) : 0;
@@ -2032,8 +2046,9 @@ static int ovs_vport_cmd_new(struct sk_buff *skb, struct genl_info *info)
 		goto exit_unlock_free;
 	}
 
-	err = ovs_vport_cmd_fill_info(vport, reply, info->snd_portid,
-				      info->snd_seq, 0, OVS_VPORT_CMD_NEW);
+	err = ovs_vport_cmd_fill_info(vport, reply, genl_info_net(info),
+				      info->snd_portid, info->snd_seq, 0,
+				      OVS_VPORT_CMD_NEW);
 
 	if (netdev_get_fwd_headroom(vport->dev) > dp->max_headroom)
 		update_headroom(dp);
@@ -2090,8 +2105,9 @@ static int ovs_vport_cmd_set(struct sk_buff *skb, struct genl_info *info)
 			goto exit_unlock_free;
 	}
 
-	err = ovs_vport_cmd_fill_info(vport, reply, info->snd_portid,
-				      info->snd_seq, 0, OVS_VPORT_CMD_NEW);
+	err = ovs_vport_cmd_fill_info(vport, reply, genl_info_net(info),
+				      info->snd_portid, info->snd_seq, 0,
+				      OVS_VPORT_CMD_NEW);
 	BUG_ON(err < 0);
 
 	ovs_unlock();
@@ -2128,8 +2144,9 @@ static int ovs_vport_cmd_del(struct sk_buff *skb, struct genl_info *info)
 		goto exit_unlock_free;
 	}
 
-	err = ovs_vport_cmd_fill_info(vport, reply, info->snd_portid,
-				      info->snd_seq, 0, OVS_VPORT_CMD_DEL);
+	err = ovs_vport_cmd_fill_info(vport, reply, genl_info_net(info),
+				      info->snd_portid, info->snd_seq, 0,
+				      OVS_VPORT_CMD_DEL);
 	BUG_ON(err < 0);
 
 	/* the vport deletion may trigger dp headroom update */
@@ -2169,8 +2186,9 @@ static int ovs_vport_cmd_get(struct sk_buff *skb, struct genl_info *info)
 	err = PTR_ERR(vport);
 	if (IS_ERR(vport))
 		goto exit_unlock_free;
-	err = ovs_vport_cmd_fill_info(vport, reply, info->snd_portid,
-				      info->snd_seq, 0, OVS_VPORT_CMD_NEW);
+	err = ovs_vport_cmd_fill_info(vport, reply, genl_info_net(info),
+				      info->snd_portid, info->snd_seq, 0,
+				      OVS_VPORT_CMD_NEW);
 	BUG_ON(err < 0);
 	rcu_read_unlock();
 
@@ -2202,6 +2220,7 @@ static int ovs_vport_cmd_dump(struct sk_buff *skb, struct netlink_callback *cb)
 		hlist_for_each_entry_rcu(vport, &dp->ports[i], dp_hash_node) {
 			if (j >= skip &&
 			    ovs_vport_cmd_fill_info(vport, skb,
+						    sock_net(skb->sk),
 						    NETLINK_CB(cb->skb).portid,
 						    cb->nlh->nlmsg_seq,
 						    NLM_F_MULTI,
@@ -2228,6 +2247,8 @@ static const struct nla_policy vport_policy[OVS_VPORT_ATTR_MAX + 1] = {
 	[OVS_VPORT_ATTR_TYPE] = { .type = NLA_U32 },
 	[OVS_VPORT_ATTR_UPCALL_PID] = { .type = NLA_U32 },
 	[OVS_VPORT_ATTR_OPTIONS] = { .type = NLA_NESTED },
+	[OVS_VPORT_ATTR_IFINDEX] = { .type = NLA_U32 },
+	[OVS_VPORT_ATTR_NETNSID] = { .type = NLA_S32 },
 };
 
 static const struct genl_ops dp_vport_genl_ops[] = {

net/openvswitch/datapath.h

@@ -200,8 +200,8 @@ int ovs_dp_upcall(struct datapath *, struct sk_buff *,
 		  uint32_t cutlen);
 
 const char *ovs_dp_name(const struct datapath *dp);
-struct sk_buff *ovs_vport_cmd_build_info(struct vport *, u32 pid, u32 seq,
-					 u8 cmd);
+struct sk_buff *ovs_vport_cmd_build_info(struct vport *vport, struct net *net,
+					 u32 portid, u32 seq, u8 cmd);
 
 int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb,
 			const struct sw_flow_actions *, struct sw_flow_key *);

net/openvswitch/dp_notify.c

@@ -30,8 +30,8 @@ static void dp_detach_port_notify(struct vport *vport)
 	struct datapath *dp;
 
 	dp = vport->dp;
-	notify = ovs_vport_cmd_build_info(vport, 0, 0,
-					  OVS_VPORT_CMD_DEL);
+	notify = ovs_vport_cmd_build_info(vport, ovs_dp_get_net(dp),
+					  0, 0, OVS_VPORT_CMD_DEL);
 	ovs_dp_detach_port(vport);
 	if (IS_ERR(notify)) {
 		genl_set_err(&dp_vport_genl_family, ovs_dp_get_net(dp), 0,