Initial MiracleCast Implementation

This initial commit contains the main "miracled" daemon that does
link-management and peer-discovery/control. The "miraclectl" tool can be
used to control this daemon during runtime.

Note that this implementation is still missing a lot of stuff. All it
currently does is provide link-management and basic peer-discovery.
Following commits will hook everything else up.

The actual Miracast/Wifi-Display related runtime control is not being
worked on, yet. Feel free to use the proof-of-concept from the OpenWFD
repository. The MiracleCast implementation will not get any such
functionality unless the basic link-management is properly working.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>

src/miracled-link.c

@@ -0,0 +1,272 @@
+/*
+ * MiracleCast - Wifi-Display/Miracast Implementation
+ *
+ * Copyright (c) 2013-2014 David Herrmann <dh.herrmann@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#define LOG_SUBSYSTEM "link"
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <systemd/sd-bus.h>
+#include "miracled.h"
+#include "miracled-wifi.h"
+#include "shl_dlist.h"
+#include "shl_log.h"
+#include "shl_util.h"
+
+static const char *link_type_to_str_table[LINK_CNT] = {
+	[LINK_VIRTUAL] = "virtual",
+	[LINK_WIFI] = "wifi",
+};
+
+const char *link_type_to_str(unsigned int type)
+{
+	if (type >= LINK_CNT)
+		return NULL;
+
+	return link_type_to_str_table[type];
+}
+
+unsigned int link_type_from_str(const char *str)
+{
+	unsigned int i;
+
+	if (!str)
+		return LINK_CNT;
+
+	for (i = 0; i < LINK_CNT; ++i)
+		if (link_type_to_str_table[i] &&
+		    !strcmp(link_type_to_str_table[i], str))
+			return i;
+
+	return LINK_CNT;
+}
+
+int link_make_name(unsigned int type, const char *interface, char **out)
+{
+	const char *tname;
+	char *name, *res;
+	size_t tlen, ilen;
+
+	tname = link_type_to_str(type);
+	if (!tname || !interface)
+		return -EINVAL;
+
+	/* hard-coded maximum of 255 just to be safe */
+	tlen = strlen(tname);
+	ilen = strlen(interface);
+	if (!tlen || tlen > 255 || !ilen || ilen > 255)
+		return -EINVAL;
+
+	if (!out)
+		return 0;
+
+	name = shl_strjoin(tname, ":", interface, NULL);
+	if (!name)
+		return log_ENOMEM();
+
+	res = sd_bus_label_escape(name);
+	free(name);
+	if (!res)
+		return log_ENOMEM();
+
+	*out = res;
+	return 0;
+}
+
+/*
+ * Wifi Handling
+ */
+
+static void link_wifi_event_fn(struct wifi *w, void *data,
+			       struct wifi_event *ev)
+{
+	struct link *l = data;
+	struct peer *p;
+
+	switch (ev->type) {
+	case WIFI_HUP:
+		/* destroy this link */
+		link_free(l);
+		break;
+	case WIFI_DEV_FOUND:
+		peer_new_wifi(l, ev->dev_found.dev, NULL);
+		break;
+	case WIFI_DEV_LOST:
+		p = wifi_dev_get_data(ev->dev_lost.dev);
+		if (!p)
+			break;
+
+		peer_free(p);
+		break;
+	case WIFI_DEV_PROVISION:
+	case WIFI_DEV_CONNECT:
+	case WIFI_DEV_DISCONNECT:
+		p = wifi_dev_get_data(ev->dev_lost.dev);
+		if (!p)
+			break;
+
+		peer_process_wifi(p, ev);
+		break;
+	default:
+		log_debug("unhandled WIFI event: %u", ev->type);
+		break;
+	}
+}
+
+static int link_wifi_init(struct link *l)
+{
+	struct wifi_dev *d;
+	int r;
+	char *path;
+
+	r = wifi_new(l->m->event, link_wifi_event_fn, l, &l->w);
+	if (r < 0)
+		return r;
+
+	path = shl_strcat("/run/wpa_supplicant/", l->interface);
+	if (!path)
+		return log_ENOMEM();
+
+	r = wifi_open(l->w, path);
+	free(path);
+
+	if (r < 0)
+		return r;
+
+	for (d = wifi_get_devs(l->w); d; d = wifi_dev_next(d))
+		peer_new_wifi(l, d, NULL);
+
+	return 0;
+}
+
+static void link_wifi_destroy(struct link *l)
+{
+	wifi_close(l->w);
+	wifi_free(l->w);
+}
+
+/*
+ * Link Handling
+ */
+
+int link_new(struct manager *m,
+	     unsigned int type,
+	     const char *interface,
+	     struct link **out)
+{
+	size_t hash = 0;
+	char *name;
+	struct link *l;
+	int r;
+
+	if (!m)
+		return log_EINVAL();
+
+	r = link_make_name(type, interface, &name);
+	if (r < 0)
+		return r;
+
+	if (shl_htable_lookup_str(&m->links, name, &hash, NULL)) {
+		free(name);
+		return -EALREADY;
+	}
+
+	log_debug("new link: %s", name);
+
+	l = calloc(1, sizeof(*l));
+	if (!l) {
+		free(name);
+		return log_ENOMEM();
+	}
+
+	l->m = m;
+	l->type = type;
+	l->name = name;
+	shl_dlist_init(&l->peers);
+
+	l->interface = strdup(interface);
+	if (!l->interface) {
+		r = log_ENOMEM();
+		goto error;
+	}
+
+	l->friendly_name = strdup("");
+	if (!l->friendly_name) {
+		r = log_ENOMEM();
+		goto error;
+	}
+
+	switch (l->type) {
+	case LINK_VIRTUAL:
+		break;
+	case LINK_WIFI:
+		r = link_wifi_init(l);
+		if (r < 0)
+			goto error;
+		break;
+	}
+
+	r = shl_htable_insert_str(&m->links, &l->name, &hash);
+	if (r < 0) {
+		log_vERR(r);
+		goto error;
+	}
+
+	++m->link_cnt;
+	log_info("new managed link: %s", l->name);
+
+	if (out)
+		*out = l;
+
+	return 0;
+
+error:
+	link_free(l);
+	return r;
+}
+
+void link_free(struct link *l)
+{
+	struct peer *p;
+
+	if (!l)
+		return;
+
+	log_debug("free link: %s", l->name);
+
+	while ((p = LINK_FIRST_PEER(l)))
+		peer_free(p);
+
+	if (shl_htable_remove_str(&l->m->links, l->name, NULL, NULL)) {
+		log_info("remove managed link: %s", l->name);
+		--l->m->link_cnt;
+	}
+
+	link_wifi_destroy(l);
+	free(l->friendly_name);
+	free(l->name);
+	free(l->interface);
+	free(l);
+}