Mikio Hara
138 lines
4.0 KiB
C
138 lines
4.0 KiB
C
/* Copyright (c) 2008, 2009 The Board of Trustees of The Leland Stanford
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* Junior University
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*
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* We are making the OpenFlow specification and associated documentation
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* (Software) available for public use and benefit with the expectation
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* that others will use, modify and enhance the Software and contribute
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* those enhancements back to the community. However, since we would
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* like to make the Software available for broadest use, with as few
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* restrictions as possible permission is hereby granted, free of
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* charge, to any person obtaining a copy of this Software to deal in
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* the Software under the copyrights without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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* The name and trademarks of copyright holder(s) may NOT be used in
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* advertising or publicity pertaining to the Software or any
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* derivatives without specific, written prior permission.
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*/
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#include <config.h>
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#include "queue.h"
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#include <assert.h>
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#include "compiler.h"
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#include "leak-checker.h"
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#include "ofpbuf.h"
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static void check_queue(struct ofp_queue *q);
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/* Initializes 'q' as an empty packet queue. */
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void
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queue_init(struct ofp_queue *q)
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{
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q->n = 0;
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q->head = NULL;
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q->tail = NULL;
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}
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/* Destroys 'q' and all of the packets that it contains. */
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void
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queue_destroy(struct ofp_queue *q)
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{
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struct ofpbuf *cur, *next;
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for (cur = q->head; cur != NULL; cur = next) {
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next = cur->next;
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ofpbuf_delete(cur);
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}
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}
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/* Removes and destroys all of the packets in 'q', rendering it empty. */
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void
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queue_clear(struct ofp_queue *q)
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{
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queue_destroy(q);
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queue_init(q);
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}
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/* Advances the first packet in 'q' from 'q->head' to 'next', which should be
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* the second packet in the queue.
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*
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* The odd, unsafe interface here allows the first packet in the queue to be
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* passed to a function for possible consumption (and destruction) and only
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* dropped from the queue if that function actually accepts it. */
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void
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queue_advance_head(struct ofp_queue *q, struct ofpbuf *next)
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{
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assert(q->n);
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assert(q->head);
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q->head = next;
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if (q->head == NULL) {
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q->tail = NULL;
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}
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q->n--;
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}
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/* Appends 'b' to the tail of 'q'. */
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void
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queue_push_tail(struct ofp_queue *q, struct ofpbuf *b)
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{
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check_queue(q);
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leak_checker_claim(b);
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b->next = NULL;
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if (q->n++) {
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q->tail->next = b;
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} else {
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q->head = b;
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}
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q->tail = b;
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check_queue(q);
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}
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/* Removes the first buffer from 'q', which must not be empty, and returns
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* it. The caller must free the buffer (with ofpbuf_delete()) when it is no
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* longer needed. */
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struct ofpbuf *
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queue_pop_head(struct ofp_queue *q)
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{
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struct ofpbuf *head = q->head;
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queue_advance_head(q, head->next);
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return head;
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}
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/* Checks the internal integrity of 'q'. For use in debugging. */
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static void
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check_queue(struct ofp_queue *q UNUSED)
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{
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#if 0
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struct ofpbuf *iter;
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size_t n;
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assert(q->n == 0
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? q->head == NULL && q->tail == NULL
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: q->head != NULL && q->tail != NULL);
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n = 0;
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for (iter = q->head; iter != NULL; iter = iter->next) {
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n++;
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assert((iter->next != NULL) == (iter != q->tail));
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}
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assert(n == q->n);
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#endif
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}
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