1 83f0f95a 2022-09-29 op /*
 2 83f0f95a 2022-09-29 op  * Copyright (c) 2002-2004 Niels Provos <provos@citi.umich.edu>
 3 83f0f95a 2022-09-29 op  * All rights reserved.
 4 83f0f95a 2022-09-29 op  *
 5 83f0f95a 2022-09-29 op  * Redistribution and use in source and binary forms, with or without
 6 83f0f95a 2022-09-29 op  * modification, are permitted provided that the following conditions
 7 83f0f95a 2022-09-29 op  * are met:
 8 83f0f95a 2022-09-29 op  * 1. Redistributions of source code must retain the above copyright
 9 83f0f95a 2022-09-29 op  *    notice, this list of conditions and the following disclaimer.
10 83f0f95a 2022-09-29 op  * 2. Redistributions in binary form must reproduce the above copyright
11 83f0f95a 2022-09-29 op  *    notice, this list of conditions and the following disclaimer in the
12 83f0f95a 2022-09-29 op  *    documentation and/or other materials provided with the distribution.
13 83f0f95a 2022-09-29 op  * 3. The name of the author may not be used to endorse or promote products
14 83f0f95a 2022-09-29 op  *    derived from this software without specific prior written permission.
15 83f0f95a 2022-09-29 op  *
16 83f0f95a 2022-09-29 op  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 83f0f95a 2022-09-29 op  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 83f0f95a 2022-09-29 op  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 83f0f95a 2022-09-29 op  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 83f0f95a 2022-09-29 op  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 83f0f95a 2022-09-29 op  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 83f0f95a 2022-09-29 op  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 83f0f95a 2022-09-29 op  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 83f0f95a 2022-09-29 op  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 83f0f95a 2022-09-29 op  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 83f0f95a 2022-09-29 op  */
27 83f0f95a 2022-09-29 op 
28 83f0f95a 2022-09-29 op #include <sys/time.h>
29 83f0f95a 2022-09-29 op #include <event.h>
30 83f0f95a 2022-09-29 op #include "config.h"
31 83f0f95a 2022-09-29 op 
32 83f0f95a 2022-09-29 op void bufferevent_read_pressure_cb(struct evbuffer *, size_t, size_t,
33 83f0f95a 2022-09-29 op     void *);
34 83f0f95a 2022-09-29 op 
35 83f0f95a 2022-09-29 op static int
36 83f0f95a 2022-09-29 op bufferevent_add(struct event *ev, int timeout)
37 83f0f95a 2022-09-29 op {
38 83f0f95a 2022-09-29 op 	struct timeval tv, *ptv = NULL;
39 83f0f95a 2022-09-29 op 
40 83f0f95a 2022-09-29 op 	if (timeout) {
41 83f0f95a 2022-09-29 op 		timerclear(&tv);
42 83f0f95a 2022-09-29 op 		tv.tv_sec = timeout;
43 83f0f95a 2022-09-29 op 		ptv = &tv;
44 83f0f95a 2022-09-29 op 	}
45 83f0f95a 2022-09-29 op 
46 83f0f95a 2022-09-29 op 	return (event_add(ev, ptv));
47 83f0f95a 2022-09-29 op }
48 83f0f95a 2022-09-29 op 
49 83f0f95a 2022-09-29 op /*
50 83f0f95a 2022-09-29 op  * This callback is executed when the size of the input buffer changes.
51 83f0f95a 2022-09-29 op  * We use it to apply back pressure on the reading side.
52 83f0f95a 2022-09-29 op  */
53 83f0f95a 2022-09-29 op void
54 83f0f95a 2022-09-29 op bufferevent_read_pressure_cb(struct evbuffer *buf, size_t old, size_t now,
55 83f0f95a 2022-09-29 op     void *arg) {
56 83f0f95a 2022-09-29 op 	struct bufferevent *bufev = arg;
57 83f0f95a 2022-09-29 op 	/*
58 83f0f95a 2022-09-29 op 	 * If we are below the watermark then reschedule reading if it's
59 83f0f95a 2022-09-29 op 	 * still enabled.
60 83f0f95a 2022-09-29 op 	 */
61 83f0f95a 2022-09-29 op 	if (bufev->wm_read.high == 0 || now < bufev->wm_read.high) {
62 83f0f95a 2022-09-29 op 		evbuffer_setcb(buf, NULL, NULL);
63 83f0f95a 2022-09-29 op 
64 83f0f95a 2022-09-29 op 		if (bufev->enabled & EV_READ)
65 83f0f95a 2022-09-29 op #if HAVE_LIBEVENT2
66 83f0f95a 2022-09-29 op 			bufferevent_add(&bufev->ev_read,
67 83f0f95a 2022-09-29 op 			    bufev->timeout_read.tv_sec);
68 83f0f95a 2022-09-29 op #else
69 83f0f95a 2022-09-29 op 			bufferevent_add(&bufev->ev_read, bufev->timeout_read);
70 83f0f95a 2022-09-29 op #endif
71 83f0f95a 2022-09-29 op 	}
72 83f0f95a 2022-09-29 op }