X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;ds=sidebyside;f=lib%2Fdpif.c;h=667e07cefaa55f6aecd7c777b3ab64f5164e2629;hb=a78b6a9e194937ba9fe1d59bccdde831b94b1734;hp=7cf5fba4b3ce82b5eab102253bf9a6ac68bd8563;hpb=112bc5f46f04c46e1d4fbfaa93f76ea39b39b66e;p=openvswitch

diff --git a/lib/dpif.c b/lib/dpif.c
index 7cf5fba4..667e07ce 100644
--- a/lib/dpif.c
+++ b/lib/dpif.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -410,19 +410,27 @@ dpif_get_dp_stats(const struct dpif *dpif, struct dpif_dp_stats *stats)
     return error;
 }
 
-/* Attempts to add 'netdev' as a port on 'dpif'.  If successful, returns 0 and
- * sets '*port_nop' to the new port's port number (if 'port_nop' is non-null).
- * On failure, returns a positive errno value and sets '*port_nop' to
- * UINT16_MAX (if 'port_nop' is non-null). */
+/* Attempts to add 'netdev' as a port on 'dpif'.  If 'port_nop' is
+ * non-null and its value is not UINT16_MAX, then attempts to use the
+ * value as the port number.
+ *
+ * If successful, returns 0 and sets '*port_nop' to the new port's port
+ * number (if 'port_nop' is non-null).  On failure, returns a positive
+ * errno value and sets '*port_nop' to UINT16_MAX (if 'port_nop' is
+ * non-null). */
 int
 dpif_port_add(struct dpif *dpif, struct netdev *netdev, uint16_t *port_nop)
 {
     const char *netdev_name = netdev_get_name(netdev);
-    uint16_t port_no;
+    uint16_t port_no = UINT16_MAX;
     int error;
 
     COVERAGE_INC(dpif_port_add);
 
+    if (port_nop) {
+        port_no = *port_nop;
+    }
+
     error = dpif->dpif_class->port_add(dpif, netdev, &port_no);
     if (!error) {
         VLOG_DBG_RL(&dpmsg_rl, "%s: added %s as port %"PRIu16,
@@ -541,6 +549,9 @@ dpif_get_max_ports(const struct dpif *dpif)
  * as the OVS_USERSPACE_ATTR_PID attribute's value, for use in flows whose
  * packets arrived on port 'port_no'.
  *
+ * A 'port_no' of UINT16_MAX is a special case: it returns a reserved PID, not
+ * allocated to any port, that the client may use for special purposes.
+ *
  * The return value is only meaningful when DPIF_UC_ACTION has been enabled in
  * the 'dpif''s listen mask.  It is allowed to change when DPIF_UC_ACTION is
  * disabled and then re-enabled, so a client that does that must be prepared to