datapath: Use unicast Netlink sockets for upcalls.

Currently we publish several multicast groups for upcalls and let
userspace sockets subscribe to them.  The benefit of this is mostly
that userspace is the one doing the subscription - the actual
multicast capability is not currently used and probably wouldn't be
even if we moved to a multiprocess model.  Despite the convenience,
multicast sockets have a number of disadvantages, primarily that
we only have a limited number of them so there could be collisions.
In addition, unicast sockets give additional flexibility to userspace
by allowing every object to potentially have a different socket
chosen by userspace for upcalls.  Finally, any future optimizations
for upcalls to reduce copying will likely not be compatible with
multicast anyways so disallowing it potentially simplifies things.

We also never unregistered the multicast groups registered for upcalls
and leaked them on module unload.  As a side effect, this solves that
problem.

Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>

1 files changed, 19 insertions, 5 deletions

diff --git a/include/openvswitch/datapath-protocol.h b/include/openvswitch/datapath-protocol.h
index fc7cc1fb..c48426f5 100644
--- a/include/openvswitch/datapath-protocol.h
+++ b/include/openvswitch/datapath-protocol.h
@@ -85,6 +85,10 @@ struct ovs_header {
  * the &struct ovs_header.  Always present in notifications.  Required in
  * %OVS_DP_NEW requests.  May be used as an alternative to specifying
  * dp_ifindex in other requests (with a dp_ifindex of 0).
+ * @OVS_DP_ATTR_UPCALL_PID: The Netlink socket in userspace that is initially
+ * set on the datapath port (for OVS_ACTION_ATTR_MISS).  Only valid on
+ * %OVS_DP_CMD_NEW requests. A value of zero indicates that upcalls should
+ * not be sent.
  * @OVS_DP_ATTR_STATS: Statistics about packets that have passed through the
  * datapath.  Always present in notifications.
  * @OVS_DP_ATTR_IPV4_FRAGS: One of %OVS_DP_FRAG_*.  Always present in
@@ -94,10 +98,6 @@ struct ovs_header {
  * @OVS_PACKET_CMD_SAMPLE.  A value of 0 samples no packets, a value of
  * %UINT32_MAX samples all packets, and intermediate values sample intermediate
  * fractions of packets.
- * @OVS_DP_ATTR_MCGROUPS: Nested attributes with multicast groups.  Each nested
- * attribute has a %OVS_PACKET_CMD_* type with a 32-bit value giving the
- * Generic Netlink multicast group number used for sending this datapath's
- * messages with that command type up to userspace.
  *
  * These attributes follow the &struct ovs_header within the Generic Netlink
  * payload for %OVS_DP_* commands.
@@ -105,10 +105,10 @@ struct ovs_header {
 enum ovs_datapath_attr {
 	OVS_DP_ATTR_UNSPEC,
 	OVS_DP_ATTR_NAME,       /* name of dp_ifindex netdev */
+	OVS_DP_ATTR_UPCALL_PID, /* Netlink PID to receive upcalls */
 	OVS_DP_ATTR_STATS,      /* struct ovs_dp_stats */
 	OVS_DP_ATTR_IPV4_FRAGS,	/* 32-bit enum ovs_frag_handling */
 	OVS_DP_ATTR_SAMPLING,   /* 32-bit fraction of packets to sample. */
-	OVS_DP_ATTR_MCGROUPS,   /* Nested attributes with multicast groups. */
 	__OVS_DP_ATTR_MAX
 };
 
@@ -174,6 +174,10 @@ enum ovs_packet_cmd {
  * extracted from the packet as nested %OVS_KEY_ATTR_* attributes.  This allows
  * userspace to adapt its flow setup strategy by comparing its notion of the
  * flow key against the kernel's.
+ * @OVS_PACKET_ATTR_UPCALL_PID: Optionally present for OVS_PACKET_CMD_EXECUTE.
+ * The Netlink socket in userspace that OVS_PACKET_CMD_USERSPACE and
+ * OVS_PACKET_CMD_SAMPLE upcalls will be directed to for actions triggered by
+ * this packet.  A value of zero indicates that upcalls should not be sent.
  * @OVS_PACKET_ATTR_USERDATA: Present for an %OVS_PACKET_CMD_ACTION
  * notification if the %OVS_ACTION_ATTR_USERSPACE, action's argument was
  * nonzero.
@@ -190,6 +194,7 @@ enum ovs_packet_attr {
 	OVS_PACKET_ATTR_UNSPEC,
 	OVS_PACKET_ATTR_PACKET,      /* Packet data. */
 	OVS_PACKET_ATTR_KEY,         /* Nested OVS_KEY_ATTR_* attributes. */
+	OVS_PACKET_ATTR_UPCALL_PID,  /* Netlink PID to receive upcalls. */
 	OVS_PACKET_ATTR_USERDATA,    /* u64 OVS_ACTION_ATTR_USERSPACE arg. */
 	OVS_PACKET_ATTR_SAMPLE_POOL, /* # sampling candidate packets so far. */
 	OVS_PACKET_ATTR_ACTIONS,     /* Nested OVS_ACTION_ATTR_* attributes. */
@@ -229,6 +234,9 @@ enum ovs_vport_cmd {
  * @OVS_VPORT_ATTR_NAME: Name of vport.  For a vport based on a network device
  * this is the name of the network device.  Maximum length %IFNAMSIZ-1 bytes
  * plus a null terminator.
+ * @OVS_VPORT_ATTR_UPCALL_PID: The Netlink socket in userspace that
+ * OVS_PACKET_CMD_MISS upcalls will be directed to for packets received on
+ * this port.  A value of zero indicates that upcalls should not be sent.
  * @OVS_VPORT_ATTR_STATS: A &struct ovs_vport_stats giving statistics for
  * packets sent or received through the vport.
  * @OVS_VPORT_ATTR_ADDRESS: A 6-byte Ethernet address for the vport.
@@ -257,6 +265,7 @@ enum ovs_vport_attr {
 	OVS_VPORT_ATTR_PORT_NO,	/* port number within datapath */
 	OVS_VPORT_ATTR_TYPE,	/* 32-bit OVS_VPORT_TYPE_* constant. */
 	OVS_VPORT_ATTR_NAME,	/* string name, up to IFNAMSIZ bytes long */
+	OVS_VPORT_ATTR_UPCALL_PID, /* Netlink PID to receive upcalls */
 	OVS_VPORT_ATTR_STATS,	/* struct ovs_vport_stats */
 	OVS_VPORT_ATTR_ADDRESS, /* hardware address */
 	OVS_VPORT_ATTR_OPTIONS, /* nested attributes, varies by vport type */
@@ -379,6 +388,10 @@ struct ovs_key_nd {
  * @OVS_FLOW_ATTR_ACTIONS: Nested %OVS_ACTION_ATTR_* attributes specifying
  * the actions to take for packets that match the key.  Always present in
  * notifications.  Required for %OVS_FLOW_CMD_NEW requests, optional
+ * @OVS_FLOW_ATTR_UPCALL_PID: The Netlink socket in userspace that
+ * OVS_PACKET_CMD_USERSPACE and OVS_PACKET_CMD_SAMPLE upcalls will be
+ * directed to for packets received on this port.  A value of zero indicates
+ * that upcalls should not be sent.
  * on %OVS_FLOW_CMD_SET request to change the existing actions, ignored for
  * other requests.
  * @OVS_FLOW_ATTR_STATS: &struct ovs_flow_stats giving statistics for this
@@ -402,6 +415,7 @@ enum ovs_flow_attr {
 	OVS_FLOW_ATTR_UNSPEC,
 	OVS_FLOW_ATTR_KEY,       /* Sequence of OVS_KEY_ATTR_* attributes. */
 	OVS_FLOW_ATTR_ACTIONS,   /* Nested OVS_ACTION_ATTR_* attributes. */
+	OVS_FLOW_ATTR_UPCALL_PID, /* Netlink PID to receive upcalls. */
 	OVS_FLOW_ATTR_STATS,     /* struct ovs_flow_stats. */
 	OVS_FLOW_ATTR_TCP_FLAGS, /* 8-bit OR'd TCP flags. */
 	OVS_FLOW_ATTR_USED,      /* u64 msecs last used in monotonic time. */