1 /* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
4 * We are making the OpenFlow specification and associated documentation
5 * (Software) available for public use and benefit with the expectation
6 * that others will use, modify and enhance the Software and contribute
7 * those enhancements back to the community. However, since we would
8 * like to make the Software available for broadest use, with as few
9 * restrictions as possible permission is hereby granted, free of
10 * charge, to any person obtaining a copy of this Software to deal in
11 * the Software under the copyrights without restriction, including
12 * without limitation the rights to use, copy, modify, merge, publish,
13 * distribute, sublicense, and/or sell copies of the Software, and to
14 * permit persons to whom the Software is furnished to do so, subject to
15 * the following conditions:
17 * The above copyright notice and this permission notice shall be
18 * included in all copies or substantial portions of the Software.
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
21 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
22 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
23 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
24 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
25 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
26 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
29 * The name and trademarks of copyright holder(s) may NOT be used in
30 * advertising or publicity pertaining to the Software or any
31 * derivatives without specific, written prior permission.
39 static void check_queue(struct ofp_queue *q);
41 /* Initializes 'q' as an empty packet queue. */
43 queue_init(struct ofp_queue *q)
50 /* Destroys 'q' and all of the packets that it contains. */
52 queue_destroy(struct ofp_queue *q)
54 struct ofpbuf *cur, *next;
55 for (cur = q->head; cur != NULL; cur = next) {
61 /* Removes and destroys all of the packets in 'q', rendering it empty. */
63 queue_clear(struct ofp_queue *q)
69 /* Advances the first packet in 'q' from 'q->head' to 'next', which should be
70 * the second packet in the queue.
72 * The odd, unsafe interface here allows the first packet in the queue to be
73 * passed to a function for possible consumption (and destruction) and only
74 * dropped from the queue if that function actually accepts it. */
76 queue_advance_head(struct ofp_queue *q, struct ofpbuf *next)
81 if (q->head == NULL) {
87 /* Appends 'b' to the tail of 'q'. */
89 queue_push_tail(struct ofp_queue *q, struct ofpbuf *b)
104 /* Removes the first buffer from 'q', which must not be empty, and returns
105 * it. The caller must free the buffer (with ofpbuf_delete()) when it is no
108 queue_pop_head(struct ofp_queue *q)
110 struct ofpbuf *head = q->head;
111 queue_advance_head(q, head->next);
115 /* Checks the internal integrity of 'q'. For use in debugging. */
117 check_queue(struct ofp_queue *q)
124 ? q->head == NULL && q->tail == NULL
125 : q->head != NULL && q->tail != NULL);
128 for (iter = q->head; iter != NULL; iter = iter->next) {
130 assert((iter->next != NULL) == (iter != q->tail));