if_medium.c revision 331722 
1/*-
2 * Copyright (c) 2010-2011 Monthadar Al Jaberi, TerraNet AB
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer,
10 *    without modification.
11 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
12 *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
13 *    redistribution must be conditioned upon including a substantially
14 *    similar Disclaimer requirement for further binary redistribution.
15 *
16 * NO WARRANTY
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
20 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
21 * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
22 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
25 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
27 * THE POSSIBILITY OF SUCH DAMAGES.
28 *
29 * $FreeBSD: stable/11/sys/dev/wtap/if_medium.c 331722 2018-03-29 02:50:57Z eadler $
30 */
31#include "if_wtapvar.h"
32#include "if_medium.h"
33
34void
35init_medium(struct wtap_medium *md)
36{
37
38	DWTAP_PRINTF("%s\n", __func__);
39	STAILQ_INIT(&md->md_pktbuf);
40	mtx_init(&md->md_mtx, "wtap_medium mtx", NULL, MTX_DEF | MTX_RECURSE);
41
42	/* Event handler for sending packets between wtaps */
43	struct eventhandler *eh = (struct eventhandler *)
44	    malloc(sizeof(struct eventhandler), M_WTAP, M_NOWAIT | M_ZERO);
45	eh->tq = taskqueue_create("wtap_tx_taskq",  M_NOWAIT | M_ZERO,
46	    taskqueue_thread_enqueue, &eh->tq);
47	taskqueue_start_threads(&eh->tq, 1, PI_NET, "%s taskq", "wtap_medium");
48	md->tx_handler = eh;
49	/* Mark medium closed by default */
50	md->open = 0;
51}
52
53void
54deinit_medium(struct wtap_medium *md)
55{
56
57	DWTAP_PRINTF("%s\n", __func__);
58	taskqueue_free(md->tx_handler->tq);
59	free(md->tx_handler, M_WTAP);
60}
61
62int
63medium_transmit(struct wtap_medium *md, int id, struct mbuf*m)
64{
65
66	mtx_lock(&md->md_mtx);
67	if (md->open == 0){
68		DWTAP_PRINTF("[%d] dropping m=%p\n", id, m);
69		m_free(m);
70		mtx_unlock(&md->md_mtx);
71		return 0;
72	}
73
74	DWTAP_PRINTF("[%d] transmiting m=%p\n", id, m);
75	struct packet *p = (struct packet *)malloc(sizeof(struct packet),
76	    M_WTAP_PACKET, M_ZERO | M_NOWAIT);
77	p->id = id;
78	p->m = m;
79
80	STAILQ_INSERT_TAIL(&md->md_pktbuf, p, pf_list);
81	taskqueue_enqueue(md->tx_handler->tq, &md->tx_handler->proc);
82	mtx_unlock(&md->md_mtx);
83
84      return 0;
85}
86
87struct packet *
88medium_get_next_packet(struct wtap_medium *md)
89{
90	struct packet *p;
91
92	mtx_lock(&md->md_mtx);
93	p = STAILQ_FIRST(&md->md_pktbuf);
94	if (p == NULL){
95		mtx_unlock(&md->md_mtx);
96		return NULL;
97	}
98
99	STAILQ_REMOVE_HEAD(&md->md_pktbuf, pf_list);
100	mtx_unlock(&md->md_mtx);
101	return p;
102}
103
104void
105medium_open(struct wtap_medium *md)
106{
107
108	mtx_lock(&md->md_mtx);
109	md->open = 1;
110	mtx_unlock(&md->md_mtx);
111}
112
113void
114medium_close(struct wtap_medium *md)
115{
116
117	mtx_lock(&md->md_mtx);
118	md->open = 0;
119	mtx_unlock(&md->md_mtx);
120}
121