366 lines
9.6 KiB
C
366 lines
9.6 KiB
C
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/*
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* Copyright (c) 2009-2012 Niels Provos, Nick Mathewson
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "event2/event-config.h"
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#include "evconfig-private.h"
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#include <sys/types.h>
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#ifdef _WIN32
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#include <winsock2.h>
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#endif
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#include "event2/util.h"
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#include "event2/buffer.h"
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#include "event2/bufferevent.h"
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#include "event2/bufferevent_struct.h"
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#include "event2/event.h"
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#include "defer-internal.h"
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#include "bufferevent-internal.h"
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#include "mm-internal.h"
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#include "util-internal.h"
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struct bufferevent_pair {
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struct bufferevent_private bev;
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struct bufferevent_pair *partner;
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/* For ->destruct() lock checking */
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struct bufferevent_pair *unlinked_partner;
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};
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/* Given a bufferevent that's really a bev part of a bufferevent_pair,
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* return that bufferevent_filtered. Returns NULL otherwise.*/
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static inline struct bufferevent_pair *
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upcast(struct bufferevent *bev)
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{
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struct bufferevent_pair *bev_p;
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if (!BEV_IS_PAIR(bev))
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return NULL;
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bev_p = EVUTIL_UPCAST(bev, struct bufferevent_pair, bev.bev);
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EVUTIL_ASSERT(BEV_IS_PAIR(&bev_p->bev.bev));
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return bev_p;
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}
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#define downcast(bev_pair) (&(bev_pair)->bev.bev)
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static inline void
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incref_and_lock(struct bufferevent *b)
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{
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struct bufferevent_pair *bevp;
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bufferevent_incref_and_lock_(b);
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bevp = upcast(b);
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if (bevp->partner)
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bufferevent_incref_and_lock_(downcast(bevp->partner));
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}
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static inline void
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decref_and_unlock(struct bufferevent *b)
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{
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struct bufferevent_pair *bevp = upcast(b);
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if (bevp->partner)
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bufferevent_decref_and_unlock_(downcast(bevp->partner));
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bufferevent_decref_and_unlock_(b);
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}
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/* XXX Handle close */
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static void be_pair_outbuf_cb(struct evbuffer *,
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const struct evbuffer_cb_info *, void *);
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static struct bufferevent_pair *
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bufferevent_pair_elt_new(struct event_base *base,
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int options)
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{
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struct bufferevent_pair *bufev;
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if (! (bufev = mm_calloc(1, sizeof(struct bufferevent_pair))))
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return NULL;
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if (bufferevent_init_common_(&bufev->bev, base, &bufferevent_ops_pair,
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options)) {
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mm_free(bufev);
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return NULL;
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}
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if (!evbuffer_add_cb(bufev->bev.bev.output, be_pair_outbuf_cb, bufev)) {
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bufferevent_free(downcast(bufev));
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return NULL;
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}
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bufferevent_init_generic_timeout_cbs_(&bufev->bev.bev);
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return bufev;
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}
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int
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bufferevent_pair_new(struct event_base *base, int options,
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struct bufferevent *pair[2])
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{
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struct bufferevent_pair *bufev1 = NULL, *bufev2 = NULL;
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int tmp_options;
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options |= BEV_OPT_DEFER_CALLBACKS;
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tmp_options = options & ~BEV_OPT_THREADSAFE;
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bufev1 = bufferevent_pair_elt_new(base, options);
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if (!bufev1)
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return -1;
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bufev2 = bufferevent_pair_elt_new(base, tmp_options);
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if (!bufev2) {
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bufferevent_free(downcast(bufev1));
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return -1;
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}
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if (options & BEV_OPT_THREADSAFE) {
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/*XXXX check return */
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bufferevent_enable_locking_(downcast(bufev2), bufev1->bev.lock);
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}
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bufev1->partner = bufev2;
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bufev2->partner = bufev1;
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evbuffer_freeze(downcast(bufev1)->input, 0);
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evbuffer_freeze(downcast(bufev1)->output, 1);
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evbuffer_freeze(downcast(bufev2)->input, 0);
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evbuffer_freeze(downcast(bufev2)->output, 1);
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pair[0] = downcast(bufev1);
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pair[1] = downcast(bufev2);
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return 0;
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}
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static void
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be_pair_transfer(struct bufferevent *src, struct bufferevent *dst,
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int ignore_wm)
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{
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size_t dst_size;
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size_t n;
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evbuffer_unfreeze(src->output, 1);
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evbuffer_unfreeze(dst->input, 0);
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if (dst->wm_read.high) {
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dst_size = evbuffer_get_length(dst->input);
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if (dst_size < dst->wm_read.high) {
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n = dst->wm_read.high - dst_size;
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evbuffer_remove_buffer(src->output, dst->input, n);
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} else {
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if (!ignore_wm)
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goto done;
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n = evbuffer_get_length(src->output);
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evbuffer_add_buffer(dst->input, src->output);
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}
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} else {
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n = evbuffer_get_length(src->output);
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evbuffer_add_buffer(dst->input, src->output);
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}
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if (n) {
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BEV_RESET_GENERIC_READ_TIMEOUT(dst);
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if (evbuffer_get_length(dst->output))
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BEV_RESET_GENERIC_WRITE_TIMEOUT(dst);
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else
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BEV_DEL_GENERIC_WRITE_TIMEOUT(dst);
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}
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bufferevent_trigger_nolock_(dst, EV_READ, 0);
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bufferevent_trigger_nolock_(src, EV_WRITE, 0);
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done:
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evbuffer_freeze(src->output, 1);
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evbuffer_freeze(dst->input, 0);
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}
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static inline int
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be_pair_wants_to_talk(struct bufferevent_pair *src,
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struct bufferevent_pair *dst)
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{
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return (downcast(src)->enabled & EV_WRITE) &&
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(downcast(dst)->enabled & EV_READ) &&
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!dst->bev.read_suspended &&
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evbuffer_get_length(downcast(src)->output);
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}
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static void
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be_pair_outbuf_cb(struct evbuffer *outbuf,
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const struct evbuffer_cb_info *info, void *arg)
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{
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struct bufferevent_pair *bev_pair = arg;
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struct bufferevent_pair *partner = bev_pair->partner;
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incref_and_lock(downcast(bev_pair));
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if (info->n_added > info->n_deleted && partner) {
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/* We got more data. If the other side's reading, then
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hand it over. */
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if (be_pair_wants_to_talk(bev_pair, partner)) {
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be_pair_transfer(downcast(bev_pair), downcast(partner), 0);
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}
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}
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decref_and_unlock(downcast(bev_pair));
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}
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static int
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be_pair_enable(struct bufferevent *bufev, short events)
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{
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struct bufferevent_pair *bev_p = upcast(bufev);
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struct bufferevent_pair *partner = bev_p->partner;
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incref_and_lock(bufev);
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if (events & EV_READ) {
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BEV_RESET_GENERIC_READ_TIMEOUT(bufev);
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}
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if ((events & EV_WRITE) && evbuffer_get_length(bufev->output))
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BEV_RESET_GENERIC_WRITE_TIMEOUT(bufev);
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/* We're starting to read! Does the other side have anything to write?*/
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if ((events & EV_READ) && partner &&
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be_pair_wants_to_talk(partner, bev_p)) {
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be_pair_transfer(downcast(partner), bufev, 0);
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}
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/* We're starting to write! Does the other side want to read? */
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if ((events & EV_WRITE) && partner &&
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be_pair_wants_to_talk(bev_p, partner)) {
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be_pair_transfer(bufev, downcast(partner), 0);
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}
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decref_and_unlock(bufev);
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return 0;
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}
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static int
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be_pair_disable(struct bufferevent *bev, short events)
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{
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if (events & EV_READ) {
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BEV_DEL_GENERIC_READ_TIMEOUT(bev);
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}
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if (events & EV_WRITE) {
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BEV_DEL_GENERIC_WRITE_TIMEOUT(bev);
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}
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return 0;
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}
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static void
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be_pair_unlink(struct bufferevent *bev)
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{
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struct bufferevent_pair *bev_p = upcast(bev);
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if (bev_p->partner) {
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bev_p->unlinked_partner = bev_p->partner;
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bev_p->partner->partner = NULL;
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bev_p->partner = NULL;
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}
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}
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/* Free *shared* lock in the latest be (since we share it between two of them). */
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static void
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be_pair_destruct(struct bufferevent *bev)
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{
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struct bufferevent_pair *bev_p = upcast(bev);
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/* Transfer ownership of the lock into partner, otherwise we will use
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* already free'd lock during freeing second bev, see next example:
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*
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* bev1->own_lock = 1
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* bev2->own_lock = 0
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* bev2->lock = bev1->lock
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*
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* bufferevent_free(bev1) # refcnt == 0 -> unlink
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* bufferevent_free(bev2) # refcnt == 0 -> unlink
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*
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* event_base_free() -> finilizers -> EVTHREAD_FREE_LOCK(bev1->lock)
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* -> BEV_LOCK(bev2->lock) <-- already freed
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*
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* Where bev1 == pair[0], bev2 == pair[1].
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*/
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if (bev_p->unlinked_partner && bev_p->bev.own_lock) {
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bev_p->unlinked_partner->bev.own_lock = 1;
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bev_p->bev.own_lock = 0;
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}
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bev_p->unlinked_partner = NULL;
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}
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static int
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be_pair_flush(struct bufferevent *bev, short iotype,
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enum bufferevent_flush_mode mode)
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{
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struct bufferevent_pair *bev_p = upcast(bev);
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struct bufferevent *partner;
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if (!bev_p->partner)
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return -1;
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if (mode == BEV_NORMAL)
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return 0;
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incref_and_lock(bev);
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partner = downcast(bev_p->partner);
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if ((iotype & EV_READ) != 0)
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be_pair_transfer(partner, bev, 1);
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if ((iotype & EV_WRITE) != 0)
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be_pair_transfer(bev, partner, 1);
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if (mode == BEV_FINISHED) {
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short what = BEV_EVENT_EOF;
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if (iotype & EV_READ)
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what |= BEV_EVENT_WRITING;
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if (iotype & EV_WRITE)
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what |= BEV_EVENT_READING;
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bufferevent_run_eventcb_(partner, what, 0);
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}
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decref_and_unlock(bev);
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return 0;
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}
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struct bufferevent *
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bufferevent_pair_get_partner(struct bufferevent *bev)
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{
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struct bufferevent_pair *bev_p;
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struct bufferevent *partner = NULL;
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bev_p = upcast(bev);
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if (! bev_p)
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return NULL;
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incref_and_lock(bev);
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if (bev_p->partner)
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partner = downcast(bev_p->partner);
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decref_and_unlock(bev);
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return partner;
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}
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const struct bufferevent_ops bufferevent_ops_pair = {
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"pair_elt",
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evutil_offsetof(struct bufferevent_pair, bev.bev),
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be_pair_enable,
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be_pair_disable,
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be_pair_unlink,
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be_pair_destruct,
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bufferevent_generic_adj_timeouts_,
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be_pair_flush,
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NULL, /* ctrl */
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||
|
|
};
|