bridge: Propagate patch port pairing errors to db.

Virtual ports like 'patch' ports that almost fully implemented on
'ofproto' layer could have internal to 'ofproto' statuses that
could not be retrieved from 'netdev' or other layers. For example,
in current implementation there is no way to get the patch port
pairing status (i.e. if it has usable peer?).

New 'ofproto-provider' API function 'vport_get_status' introduced to
cover this gap. It allowes 'bridge' layer to retrive current status
of ofproto virtual ports and propagate it to DB.
For now we're only interested in pairing errors of 'patch' ports.
That are propagated to the 'error' column of the 'Interface' table.

Ex.:

  $ ovs-vsctl show
    ...
    Bridge "br1"
      ...
      Port "patch1"
        Interface "patch1"
          type: patch
          options: {peer="patch0"}
          error: "No usable peer 'patch0' exists in 'system' datapath."

    Bridge "br0"
      datapath_type: netdev
      ...
      Port "patch0"
        Interface "patch0"
          type: patch
          options: {peer="patch1"}
          error: "No usable peer 'patch1' exists in 'netdev' datapath."

Acked-by: Eelco Chaudron <[email protected]>
Signed-off-by: Ilya Maximets <[email protected]>
Signed-off-by: Ben Pfaff <[email protected]>

ofproto/ofproto-dpif.c

@@ -3767,6 +3767,26 @@ port_get_stats(const struct ofport *ofport_, struct netdev_stats *stats)
     return error;
 }
 
+static int
+vport_get_status(const struct ofport *ofport_, char **errp)
+{
+    struct ofport_dpif *ofport = ofport_dpif_cast(ofport_);
+    char *peer_name;
+
+    if (!netdev_vport_is_patch(ofport->up.netdev) || ofport->peer) {
+        return 0;
+    }
+
+    peer_name = netdev_vport_patch_peer(ofport->up.netdev);
+    if (!peer_name) {
+        return 0;
+    }
+    *errp = xasprintf("No usable peer '%s' exists in '%s' datapath.",
+                      peer_name, ofport->up.ofproto->type);
+    free(peer_name);
+    return EINVAL;
+}
+
 static int
 port_get_lacp_stats(const struct ofport *ofport_, struct lacp_slave_stats *stats)
 {
@@ -6045,6 +6065,7 @@ const struct ofproto_class ofproto_dpif_class = {
     port_del,
     port_set_config,
     port_get_stats,
+    vport_get_status,
     port_dump_start,
     port_dump_next,
     port_dump_done,

ofproto/ofproto-provider.h

@@ -1076,6 +1076,17 @@ struct ofproto_class {
     int (*port_get_stats)(const struct ofport *port,
                           struct netdev_stats *stats);
 
+    /* Get status of the virtual port (ex. tunnel, patch).
+     *
+     * Returns '0' if 'port' is not a virtual port or has no errors.
+     * Otherwise, stores the error string in '*errp' and returns positive errno
+     * value. The caller is responsible for freeing '*errp' (with free()).
+     *
+     * This function may be a null pointer if the ofproto implementation does
+     * not support any virtual ports or their states.
+     */
+    int (*vport_get_status)(const struct ofport *port, char **errp);
+
     /* Port iteration functions.
      *
      * The client might not be entirely in control of the ports within an

ofproto/ofproto.c

@@ -2627,6 +2627,17 @@ ofproto_port_get_stats(const struct ofport *port, struct netdev_stats *stats)
     return error;
 }
 
+int
+ofproto_vport_get_status(const struct ofproto *ofproto, ofp_port_t ofp_port,
+                         char **errp)
+{
+    struct ofport *ofport = ofproto_get_port(ofproto, ofp_port);
+
+    return (ofport && ofproto->ofproto_class->vport_get_status)
+           ? ofproto->ofproto_class->vport_get_status(ofport, errp)
+           : EOPNOTSUPP;
+}
+
 static int
 update_port(struct ofproto *ofproto, const char *name)
 {

ofproto/ofproto.h

@@ -317,6 +317,9 @@ void ofproto_port_set_config(struct ofproto *, ofp_port_t ofp_port,
                              const struct smap *cfg);
 int ofproto_port_get_stats(const struct ofport *, struct netdev_stats *stats);
 
+int ofproto_vport_get_status(const struct ofproto *, ofp_port_t ofp_port,
+                             char **errp);
+
 int ofproto_port_query_by_name(const struct ofproto *, const char *devname,
                                struct ofproto_port *);
 

vswitchd/bridge.c

@@ -2256,11 +2256,24 @@ static void
 iface_refresh_ofproto_status(struct iface *iface)
 {
     int current;
+    int error;
+    char *errp = NULL;
 
     if (iface_is_synthetic(iface)) {
         return;
     }
 
+    error = ofproto_vport_get_status(iface->port->bridge->ofproto,
+                                     iface->ofp_port, &errp);
+    if (error && error != EOPNOTSUPP) {
+        /* Need to verify to avoid race with transaction from
+         * 'bridge_reconfigure' that clears errors explicitly. */
+        ovsrec_interface_verify_error(iface->cfg);
+        ovsrec_interface_set_error(iface->cfg,
+                                   errp ? errp : ovs_strerror(error));
+        free(errp);
+    }
+
     current = ofproto_port_is_lacp_current(iface->port->bridge->ofproto,
                                            iface->ofp_port);
     if (current >= 0) {