Add stats message that allows querying description of components in OpenFlow.

[sliver-openvswitch.git] / lib / queue.c

diff --git a/lib/queue.c b/lib/queue.c
index 7f3f817..f06c8e9 100644 (file)
--- a/lib/queue.c
+++ b/lib/queue.c
@@ -1,30 +1,44 @@
-/* Copyright (C) 2008 Board of Trustees, Leland Stanford Jr. University.
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to
- * deal in the Software without restriction, including without limitation the
- * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
- * sell copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
- * IN THE SOFTWARE.
+/* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
+ * Junior University
+ * 
+ * We are making the OpenFlow specification and associated documentation
+ * (Software) available for public use and benefit with the expectation
+ * that others will use, modify and enhance the Software and contribute
+ * those enhancements back to the community. However, since we would
+ * like to make the Software available for broadest use, with as few
+ * restrictions as possible permission is hereby granted, free of
+ * charge, to any person obtaining a copy of this Software to deal in
+ * the Software under the copyrights without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ * 
+ * The name and trademarks of copyright holder(s) may NOT be used in
+ * advertising or publicity pertaining to the Software or any
+ * derivatives without specific, written prior permission.
  */
 
+#include <config.h>
 #include "queue.h"
 #include <assert.h>
 #include "buffer.h"
 
 static void check_queue(struct queue *q);
 
+/* Initializes 'q' as an empty packet queue. */
 void
 queue_init(struct queue *q)
 {
@@ -33,6 +47,7 @@ queue_init(struct queue *q)
     q->tail = NULL;
 }
 
+/* Destroys 'q' and all of the packets that it contains. */
 void
 queue_destroy(struct queue *q)
 {
@@ -43,6 +58,7 @@ queue_destroy(struct queue *q)
     }
 }
 
+/* Removes and destroys all of the packets in 'q', rendering it empty. */
 void
 queue_clear(struct queue *q)
 {
@@ -50,6 +66,12 @@ queue_clear(struct queue *q)
     queue_init(q);
 }
 
+/* Advances the first packet in 'q' from 'q->head' to 'next', which should be
+ * the second packet in the queue.
+ *
+ * The odd, unsafe interface here allows the first packet in the queue to be
+ * passed to a function for possible consumption (and destruction) and only
+ * dropped from the queue if that function actually accepts it. */
 void
 queue_advance_head(struct queue *q, struct buffer *next)
 {
@@ -62,6 +84,7 @@ queue_advance_head(struct queue *q, struct buffer *next)
     q->n--;
 }
 
+/* Appends 'b' to the tail of 'q'. */
 void
 queue_push_tail(struct queue *q, struct buffer *b)
 {
@@ -78,6 +101,18 @@ queue_push_tail(struct queue *q, struct buffer *b)
     check_queue(q);
 }
 
+/* Removes the first buffer from 'q', which must not be empty, and returns
+ * it.  The caller must free the buffer (with buffer_delete()) when it is no
+ * longer needed. */
+struct buffer *
+queue_pop_head(struct queue *q)
+{
+    struct buffer *head = q->head;
+    queue_advance_head(q, head->next);
+    return head;
+}
+
+/* Checks the internal integrity of 'q'.  For use in debugging. */
 static void
 check_queue(struct queue *q)
 {