mirror of
https://github.com/openvswitch/ovs
synced 2025-08-22 18:07:40 +00:00
121 lines
2.9 KiB
C
121 lines
2.9 KiB
C
/*
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* Copyright (c) 2008, 2009, 2010 Nicira Networks.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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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 ovs_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 ovs_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 ovs_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 ovs_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 ovs_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 ovs_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 ovs_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 ovs_queue *q OVS_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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