Introduce wtap, the beginnings of a net80211 wlan simulator.

This introduces:

* a basic wtap interface
* a HAL, which implements an abstraction layer for implementing
  different device behavious;
* A visibility plugin, which allows for control over which nodes
  see other nodes (useful for mesh work.)

It doesn't yet implement sta/adhoc/hostap modes but these are quite
feasible to implement.

Monthadar uses it to do 802.11s mesh verification.

The userland tools will be committed in a follow-up commit.

Submitted by:	Monthadar Al Jaberi <monthadar@gmail.com>

1 files changed, 120 insertions, 0 deletions

diff --git a/sys/dev/wtap/if_medium.c b/sys/dev/wtap/if_medium.c
new file mode 100644
index 0000000..74faa5b1
--- /dev/null
+++ b/sys/dev/wtap/if_medium.c
@@ -0,0 +1,120 @@
+/*-
+ * Copyright (c) 2010-2011 Monthadar Al Jaberi, TerraNet AB
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer,
+ *    without modification.
+ * 2. Redistributions in binary form must reproduce at minimum a disclaimer
+ *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
+ *    redistribution must be conditioned upon including a substantially
+ *    similar Disclaimer requirement for further binary redistribution.
+ *
+ * NO WARRANTY
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
+ * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
+ * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
+ * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGES.
+ *
+ * $FreeBSD$
+ */
+#include "if_wtapvar.h"
+#include "if_medium.h"
+
+void
+init_medium(struct wtap_medium *md)
+{
+
+	DWTAP_PRINTF("%s\n", __func__);
+	STAILQ_INIT(&md->md_pktbuf);
+	mtx_init(&md->md_mtx, "wtap_medium mtx", NULL, MTX_DEF | MTX_RECURSE);
+
+	/* Event handler for sending packets between wtaps */
+	struct eventhandler *eh = (struct eventhandler *)
+	    malloc(sizeof(struct eventhandler), M_WTAP, M_NOWAIT | M_ZERO);
+	eh->tq = taskqueue_create("wtap_tx_taskq",  M_NOWAIT | M_ZERO,
+	    taskqueue_thread_enqueue, &eh->tq);
+	taskqueue_start_threads(&eh->tq, 1, PI_NET, "%s taskq", "wtap_medium");
+	md->tx_handler = eh;
+	/* Mark medium closed by default */
+	md->open = 0;
+}
+
+void
+deinit_medium(struct wtap_medium *md)
+{
+
+	DWTAP_PRINTF("%s\n", __func__);
+	taskqueue_free(md->tx_handler->tq);
+	free(md->tx_handler, M_WTAP);
+}
+
+int
+medium_transmit(struct wtap_medium *md, int id, struct mbuf*m)
+{
+
+	mtx_lock(&md->md_mtx);
+	if (md->open == 0){
+		DWTAP_PRINTF("[%d] dropping m=%p\n", id, m);
+		m_free(m);
+		mtx_unlock(&md->md_mtx);
+		return 0;
+	}
+
+	DWTAP_PRINTF("[%d] transmiting m=%p\n", id, m);
+	struct packet *p = (struct packet *)malloc(sizeof(struct packet),
+	    M_WTAP_PACKET, M_ZERO | M_NOWAIT);
+	p->id = id;
+	p->m = m;
+
+	STAILQ_INSERT_TAIL(&md->md_pktbuf, p, pf_list);
+	taskqueue_enqueue(md->tx_handler->tq, &md->tx_handler->proc);
+	mtx_unlock(&md->md_mtx);
+
+      return 0;
+}
+
+struct packet *
+medium_get_next_packet(struct wtap_medium *md)
+{
+	struct packet *p;
+
+	mtx_lock(&md->md_mtx);
+	p = STAILQ_FIRST(&md->md_pktbuf);
+	if (p == NULL){
+		mtx_unlock(&md->md_mtx);
+		return NULL;
+	}
+
+	STAILQ_REMOVE_HEAD(&md->md_pktbuf, pf_list);
+	mtx_unlock(&md->md_mtx);
+	return p;
+}
+
+void
+medium_open(struct wtap_medium *md)
+{
+
+	mtx_lock(&md->md_mtx);
+	md->open = 1;
+	mtx_unlock(&md->md_mtx);
+}
+
+void
+medium_close(struct wtap_medium *md)
+{
+
+	mtx_lock(&md->md_mtx);
+	md->open = 0;
+	mtx_unlock(&md->md_mtx);
+}