Merge branch 'android-app'

This branch introduces a userland IPsec implementation (libipsec) and an
Android App which targets the VpnService API that is provided by Android 4+.

The implementation is based on the bachelor thesis 'Userland IPsec for
Android 4' by Giuliano Grassi and Ralf Sager.

1 files changed, 533 insertions, 0 deletions

diff --git a/src/frontends/android/jni/libandroidbridge/backend/android_service.c b/src/frontends/android/jni/libandroidbridge/backend/android_service.c
new file mode 100644
index 000000000..dfc0d2342
--- /dev/null
+++ b/src/frontends/android/jni/libandroidbridge/backend/android_service.c
@@ -0,0 +1,533 @@
+/*
+ * Copyright (C) 2010-2012 Tobias Brunner
+ * Copyright (C) 2012 Giuliano Grassi
+ * Copyright (C) 2012 Ralf Sager
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include <errno.h>
+#include <unistd.h>
+
+#include "android_service.h"
+#include "../charonservice.h"
+#include "../vpnservice_builder.h"
+
+#include <daemon.h>
+#include <library.h>
+#include <ipsec.h>
+#include <processing/jobs/callback_job.h>
+#include <threading/rwlock.h>
+#include <threading/thread.h>
+
+typedef struct private_android_service_t private_android_service_t;
+
+#define TUN_DEFAULT_MTU 1400
+
+/**
+ * private data of Android service
+ */
+struct private_android_service_t {
+
+	/**
+	 * public interface
+	 */
+	android_service_t public;
+
+	/**
+	 * current IKE_SA
+	 */
+	ike_sa_t *ike_sa;
+
+	/**
+	 * local ipv4 address
+	 */
+	char *local_address;
+
+	/**
+	 * gateway
+	 */
+	char *gateway;
+
+	/**
+	 * username
+	 */
+	char *username;
+
+	/**
+	 * lock to safely access the TUN device fd
+	 */
+	rwlock_t *lock;
+
+	/**
+	 * TUN device file descriptor
+	 */
+	int tunfd;
+
+};
+
+/**
+ * Outbound callback
+ */
+static void send_esp(void *data, esp_packet_t *packet)
+{
+	charon->sender->send_no_marker(charon->sender, (packet_t*)packet);
+}
+
+/**
+ * Inbound callback
+ */
+static void deliver_plain(private_android_service_t *this,
+						  ip_packet_t *packet)
+{
+	chunk_t encoding;
+	ssize_t len;
+
+	encoding = packet->get_encoding(packet);
+
+	this->lock->read_lock(this->lock);
+	if (this->tunfd < 0)
+	{	/* the TUN device is already closed */
+		this->lock->unlock(this->lock);
+		packet->destroy(packet);
+		return;
+	}
+	len = write(this->tunfd, encoding.ptr, encoding.len);
+	this->lock->unlock(this->lock);
+
+	if (len < 0 || len != encoding.len)
+	{
+		DBG1(DBG_DMN, "failed to write packet to TUN device: %s",
+			 strerror(errno));
+	}
+	packet->destroy(packet);
+}
+
+/**
+ * Receiver callback
+ */
+static void receiver_esp_cb(void *data, packet_t *packet)
+{
+	esp_packet_t *esp_packet;
+
+	esp_packet = esp_packet_create_from_packet(packet);
+	ipsec->processor->queue_inbound(ipsec->processor, esp_packet);
+}
+
+/**
+ * Job handling outbound plaintext packets
+ */
+static job_requeue_t handle_plain(private_android_service_t *this)
+{
+	ip_packet_t *packet;
+	chunk_t raw;
+	fd_set set;
+	ssize_t len;
+	int tunfd;
+	bool old;
+
+	FD_ZERO(&set);
+
+	this->lock->read_lock(this->lock);
+	if (this->tunfd < 0)
+	{	/* the TUN device is already closed */
+		this->lock->unlock(this->lock);
+		return JOB_REQUEUE_NONE;
+	}
+	tunfd = this->tunfd;
+	FD_SET(tunfd, &set);
+	this->lock->unlock(this->lock);
+
+	old = thread_cancelability(TRUE);
+	len = select(tunfd + 1, &set, NULL, NULL, NULL);
+	thread_cancelability(old);
+
+	if (len < 0)
+	{
+		DBG1(DBG_DMN, "select on TUN device failed: %s", strerror(errno));
+		return JOB_REQUEUE_NONE;
+	}
+
+	raw = chunk_alloc(TUN_DEFAULT_MTU);
+	len = read(tunfd, raw.ptr, raw.len);
+	if (len < 0)
+	{
+		DBG1(DBG_DMN, "reading from TUN device failed: %s", strerror(errno));
+		chunk_free(&raw);
+		return JOB_REQUEUE_FAIR;
+	}
+	raw.len = len;
+
+	packet = ip_packet_create(raw);
+	if (packet)
+	{
+		ipsec->processor->queue_outbound(ipsec->processor, packet);
+	}
+	else
+	{
+		DBG1(DBG_DMN, "invalid IP packet read from TUN device");
+	}
+	return JOB_REQUEUE_DIRECT;
+}
+
+/**
+ * Add a route to the TUN device builder
+ */
+static bool add_route(vpnservice_builder_t *builder, host_t *net,
+					  u_int8_t prefix)
+{
+	/* if route is 0.0.0.0/0, split it into two routes 0.0.0.0/1 and
+	 * 128.0.0.0/1 because otherwise it would conflict with the current default
+	 * route */
+	if (net->is_anyaddr(net) && prefix == 0)
+	{
+		bool success;
+
+		success = add_route(builder, net, 1);
+		net = host_create_from_string("128.0.0.0", 0);
+		success = success && add_route(builder, net, 1);
+		net->destroy(net);
+		return success;
+	}
+	return builder->add_route(builder, net, prefix);
+}
+
+/**
+ * Generate and set routes from installed IPsec policies
+ */
+static bool add_routes(vpnservice_builder_t *builder, child_sa_t *child_sa)
+{
+	traffic_selector_t *src_ts, *dst_ts;
+	enumerator_t *enumerator;
+	bool success = TRUE;
+
+	enumerator = child_sa->create_policy_enumerator(child_sa);
+	while (success && enumerator->enumerate(enumerator, &src_ts, &dst_ts))
+	{
+		host_t *net;
+		u_int8_t prefix;
+
+		dst_ts->to_subnet(dst_ts, &net, &prefix);
+		success = add_route(builder, net, prefix);
+		net->destroy(net);
+	}
+	enumerator->destroy(enumerator);
+	return success;
+}
+
+/**
+ * Setup a new TUN device for the supplied SAs, also queues a job that
+ * reads packets from this device.
+ * Additional information such as DNS servers are gathered in appropriate
+ * listeners asynchronously.  To be sure every required bit of information is
+ * available this should be called after the CHILD_SA has been established.
+ */
+static bool setup_tun_device(private_android_service_t *this,
+							 ike_sa_t *ike_sa, child_sa_t *child_sa)
+{
+	vpnservice_builder_t *builder;
+	host_t *vip;
+	int tunfd;
+
+	DBG1(DBG_DMN, "setting up TUN device for CHILD_SA %s{%u}",
+		 child_sa->get_name(child_sa), child_sa->get_reqid(child_sa));
+	vip = ike_sa->get_virtual_ip(ike_sa, TRUE);
+	if (!vip || vip->is_anyaddr(vip))
+	{
+		DBG1(DBG_DMN, "setting up TUN device failed, no virtual IP found");
+		return FALSE;
+	}
+
+	builder = charonservice->get_vpnservice_builder(charonservice);
+	if (!builder->add_address(builder, vip) ||
+		!add_routes(builder, child_sa) ||
+		!builder->set_mtu(builder, TUN_DEFAULT_MTU))
+	{
+		return FALSE;
+	}
+
+	tunfd = builder->establish(builder);
+	if (tunfd == -1)
+	{
+		return FALSE;
+	}
+
+	this->lock->write_lock(this->lock);
+	this->tunfd = tunfd;
+	this->lock->unlock(this->lock);
+
+	DBG1(DBG_DMN, "successfully created TUN device");
+
+	charon->receiver->add_esp_cb(charon->receiver,
+								(receiver_esp_cb_t)receiver_esp_cb, NULL);
+	ipsec->processor->register_inbound(ipsec->processor,
+									  (ipsec_inbound_cb_t)deliver_plain, this);
+	ipsec->processor->register_outbound(ipsec->processor,
+									   (ipsec_outbound_cb_t)send_esp, NULL);
+
+	lib->processor->queue_job(lib->processor,
+		(job_t*)callback_job_create((callback_job_cb_t)handle_plain, this,
+									NULL, (callback_job_cancel_t)return_false));
+	return TRUE;
+}
+
+/**
+ * Close the current tun device
+ */
+static void close_tun_device(private_android_service_t *this)
+{
+	int tunfd;
+
+	this->lock->write_lock(this->lock);
+	if (this->tunfd < 0)
+	{	/* already closed (or never created) */
+		this->lock->unlock(this->lock);
+		return;
+	}
+	tunfd = this->tunfd;
+	this->tunfd = -1;
+	this->lock->unlock(this->lock);
+
+	ipsec->processor->unregister_outbound(ipsec->processor,
+										 (ipsec_outbound_cb_t)send_esp);
+	ipsec->processor->unregister_inbound(ipsec->processor,
+										(ipsec_inbound_cb_t)deliver_plain);
+	charon->receiver->del_esp_cb(charon->receiver,
+								(receiver_esp_cb_t)receiver_esp_cb);
+	close(tunfd);
+}
+
+METHOD(listener_t, child_updown, bool,
+	private_android_service_t *this, ike_sa_t *ike_sa, child_sa_t *child_sa,
+	bool up)
+{
+	if (this->ike_sa == ike_sa)
+	{
+		if (up)
+		{
+			/* disable the hooks registered to catch initiation failures */
+			this->public.listener.ike_updown = NULL;
+			this->public.listener.ike_state_change = NULL;
+			if (!setup_tun_device(this, ike_sa, child_sa))
+			{
+				DBG1(DBG_DMN, "failed to setup TUN device");
+				charonservice->update_status(charonservice,
+											 CHARONSERVICE_GENERIC_ERROR);
+				return FALSE;
+
+			}
+			charonservice->update_status(charonservice,
+										 CHARONSERVICE_CHILD_STATE_UP);
+		}
+		else
+		{
+			close_tun_device(this);
+			charonservice->update_status(charonservice,
+										 CHARONSERVICE_CHILD_STATE_DOWN);
+			return FALSE;
+		}
+	}
+	return TRUE;
+}
+
+METHOD(listener_t, ike_updown, bool,
+	private_android_service_t *this, ike_sa_t *ike_sa, bool up)
+{
+	/* this callback is only registered during initiation, so if the IKE_SA
+	 * goes down we assume an authentication error */
+	if (this->ike_sa == ike_sa && !up)
+	{
+		charonservice->update_status(charonservice,
+									 CHARONSERVICE_AUTH_ERROR);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+METHOD(listener_t, ike_state_change, bool,
+	private_android_service_t *this, ike_sa_t *ike_sa, ike_sa_state_t state)
+{
+	/* this call back is only registered during initiation */
+	if (this->ike_sa == ike_sa && state == IKE_DESTROYING)
+	{
+		charonservice->update_status(charonservice,
+									 CHARONSERVICE_UNREACHABLE_ERROR);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+METHOD(listener_t, alert, bool,
+	private_android_service_t *this, ike_sa_t *ike_sa, alert_t alert,
+	va_list args)
+{
+	if (this->ike_sa == ike_sa)
+	{
+		switch (alert)
+		{
+			case ALERT_PEER_ADDR_FAILED:
+				charonservice->update_status(charonservice,
+											 CHARONSERVICE_LOOKUP_ERROR);
+				break;
+			case ALERT_PEER_AUTH_FAILED:
+				charonservice->update_status(charonservice,
+											 CHARONSERVICE_PEER_AUTH_ERROR);
+				break;
+			default:
+				break;
+		}
+	}
+	return TRUE;
+}
+
+METHOD(listener_t, ike_rekey, bool,
+	private_android_service_t *this, ike_sa_t *old, ike_sa_t *new)
+{
+	if (this->ike_sa == old)
+	{
+		this->ike_sa = new;
+	}
+	return TRUE;
+}
+
+static job_requeue_t initiate(private_android_service_t *this)
+{
+	identification_t *gateway, *user;
+	ike_cfg_t *ike_cfg;
+	peer_cfg_t *peer_cfg;
+	child_cfg_t *child_cfg;
+	traffic_selector_t *ts;
+	ike_sa_t *ike_sa;
+	auth_cfg_t *auth;
+	lifetime_cfg_t lifetime = {
+		.time = {
+			.life = 10800, /* 3h */
+			.rekey = 10200, /* 2h50min */
+			.jitter = 300 /* 5min */
+		}
+	};
+
+	ike_cfg = ike_cfg_create(TRUE, TRUE, this->local_address, FALSE,
+							 charon->socket->get_port(charon->socket, FALSE),
+							 this->gateway, FALSE, IKEV2_UDP_PORT);
+	ike_cfg->add_proposal(ike_cfg, proposal_create_default(PROTO_IKE));
+
+	peer_cfg = peer_cfg_create("android", IKEV2, ike_cfg, CERT_SEND_IF_ASKED,
+							   UNIQUE_REPLACE, 1, /* keyingtries */
+							   36000, 0, /* rekey 10h, reauth none */
+							   600, 600, /* jitter, over 10min */
+							   TRUE, FALSE, /* mobike, aggressive */
+							   0, 0, /* DPD delay, timeout */
+							   host_create_from_string("0.0.0.0", 0) /* virt */,
+							   NULL, FALSE, NULL, NULL); /* pool, mediation */
+
+
+	auth = auth_cfg_create();
+	auth->add(auth, AUTH_RULE_AUTH_CLASS, AUTH_CLASS_EAP);
+	user = identification_create_from_string(this->username);
+	auth->add(auth, AUTH_RULE_IDENTITY, user);
+	peer_cfg->add_auth_cfg(peer_cfg, auth, TRUE);
+	auth = auth_cfg_create();
+	auth->add(auth, AUTH_RULE_AUTH_CLASS, AUTH_CLASS_PUBKEY);
+	gateway = identification_create_from_string(this->gateway);
+	auth->add(auth, AUTH_RULE_IDENTITY, gateway);
+	peer_cfg->add_auth_cfg(peer_cfg, auth, FALSE);
+
+	child_cfg = child_cfg_create("android", &lifetime, NULL, TRUE, MODE_TUNNEL,
+								 ACTION_NONE, ACTION_NONE, ACTION_NONE, FALSE,
+								 0, 0, NULL, NULL, 0);
+	child_cfg->add_proposal(child_cfg, proposal_create_default(PROTO_ESP));
+	ts = traffic_selector_create_dynamic(0, 0, 65535);
+	child_cfg->add_traffic_selector(child_cfg, TRUE, ts);
+	ts = traffic_selector_create_from_string(0, TS_IPV4_ADDR_RANGE, "0.0.0.0",
+											 0, "255.255.255.255", 65535);
+	child_cfg->add_traffic_selector(child_cfg, FALSE, ts);
+	peer_cfg->add_child_cfg(peer_cfg, child_cfg);
+
+	/* get us an IKE_SA */
+	ike_sa = charon->ike_sa_manager->checkout_by_config(charon->ike_sa_manager,
+														peer_cfg);
+	if (!ike_sa)
+	{
+		peer_cfg->destroy(peer_cfg);
+		charonservice->update_status(charonservice,
+									 CHARONSERVICE_GENERIC_ERROR);
+		return JOB_REQUEUE_NONE;
+	}
+	if (!ike_sa->get_peer_cfg(ike_sa))
+	{
+		ike_sa->set_peer_cfg(ike_sa, peer_cfg);
+	}
+	peer_cfg->destroy(peer_cfg);
+
+	/* store the IKE_SA so we can track its progress */
+	this->ike_sa = ike_sa;
+
+	/* get an additional reference because initiate consumes one */
+	child_cfg->get_ref(child_cfg);
+	if (ike_sa->initiate(ike_sa, child_cfg, 0, NULL, NULL) != SUCCESS)
+	{
+		DBG1(DBG_CFG, "failed to initiate tunnel");
+		charon->ike_sa_manager->checkin_and_destroy(charon->ike_sa_manager,
+			ike_sa);
+		return JOB_REQUEUE_NONE;
+	}
+	charon->ike_sa_manager->checkin(charon->ike_sa_manager, ike_sa);
+	return JOB_REQUEUE_NONE;
+}
+
+METHOD(android_service_t, destroy, void,
+	private_android_service_t *this)
+{
+	charon->bus->remove_listener(charon->bus, &this->public.listener);
+	/* make sure the tun device is actually closed */
+	close_tun_device(this);
+	this->lock->destroy(this->lock);
+	free(this->local_address);
+	free(this->username);
+	free(this->gateway);
+	free(this);
+}
+
+/**
+ * See header
+ */
+android_service_t *android_service_create(char *local_address, char *gateway,
+										  char *username)
+{
+	private_android_service_t *this;
+
+	INIT(this,
+		.public = {
+			.listener = {
+				.ike_rekey = _ike_rekey,
+				.ike_updown = _ike_updown,
+				.ike_state_change = _ike_state_change,
+				.child_updown = _child_updown,
+				.alert = _alert,
+			},
+			.destroy = _destroy,
+		},
+		.lock = rwlock_create(RWLOCK_TYPE_DEFAULT),
+		.local_address = local_address,
+		.username = username,
+		.gateway = gateway,
+		.tunfd = -1,
+	);
+
+	charon->bus->add_listener(charon->bus, &this->public.listener);
+
+	lib->processor->queue_job(lib->processor,
+		(job_t*)callback_job_create((callback_job_cb_t)initiate, this,
+									NULL, NULL));
+	return &this->public;
+}