Make it easy to check if an address is locally usable via changed get_interface() method

src/libcharon/plugins/stroke/stroke_config.c

@@ -191,42 +191,34 @@ static ike_cfg_t *build_ike_cfg(private_stroke_config_t *this, stroke_msg_t *msg
 {
 	stroke_end_t tmp_end;
 	ike_cfg_t *ike_cfg;
-	char *interface;
 	host_t *host;
 	u_int16_t ikeport;
 
 	host = host_create_from_dns(msg->add_conn.other.address, 0, 0);
 	if (host)
 	{
-		interface = hydra->kernel_interface->get_interface(
+		if (hydra->kernel_interface->get_interface(hydra->kernel_interface,
-												hydra->kernel_interface, host);
+												   host, NULL))
-		host->destroy(host);
-		if (interface)
 		{
 			DBG2(DBG_CFG, "left is other host, swapping ends");
 			tmp_end = msg->add_conn.me;
 			msg->add_conn.me = msg->add_conn.other;
 			msg->add_conn.other = tmp_end;
-			free(interface);
+			host->destroy(host);
 		}
 		else
 		{
+			host->destroy(host);
 			host = host_create_from_dns(msg->add_conn.me.address, 0, 0);
 			if (host)
 			{
-				interface = hydra->kernel_interface->get_interface(
+				if (!hydra->kernel_interface->get_interface(
-												hydra->kernel_interface, host);
+										hydra->kernel_interface, host, NULL))
-				host->destroy(host);
-				if (!interface)
 				{
 					DBG1(DBG_CFG, "left nor right host is our side, "
 						 "assuming left=local");
 				}
-				else
+				host->destroy(host);
-				{
-					free(interface);
-				}
-
 			}
 		}
 	}

src/libcharon/plugins/updown/updown_listener.c

@@ -267,9 +267,8 @@ METHOD(listener_t, child_updown, bool,
 
 		if (up)
 		{
-			iface = hydra->kernel_interface->get_interface(
+			if (hydra->kernel_interface->get_interface(hydra->kernel_interface,
-												hydra->kernel_interface, me);
+													   me, &iface))
-			if (iface)
 			{
 				cache_iface(this, child_sa->get_reqid(child_sa), iface);
 			}

src/libhydra/kernel/kernel_interface.c

@@ -291,14 +291,14 @@ METHOD(kernel_interface_t, get_nexthop, host_t*,
 	return this->net->get_nexthop(this->net, dest, src);
 }
 
-METHOD(kernel_interface_t, get_interface, char*,
+METHOD(kernel_interface_t, get_interface, bool,
-	private_kernel_interface_t *this, host_t *host)
+	private_kernel_interface_t *this, host_t *host, char **name)
 {
 	if (!this->net)
 	{
 		return NULL;
 	}
-	return this->net->get_interface(this->net, host);
+	return this->net->get_interface(this->net, host, name);
 }
 
 METHOD(kernel_interface_t, create_address_enumerator, enumerator_t*,

src/libhydra/kernel/kernel_interface.h

@@ -308,9 +308,10 @@ struct kernel_interface_t {
 	 * Get the interface name of a local address.
 	 *
 	 * @param host			address to get interface name from
-	 * @return				allocated interface name, or NULL if not found
+	 * @param name			allocated interface name (optional)
+	 * @return				TRUE if interface found and usable
 	 */
-	char* (*get_interface) (kernel_interface_t *this, host_t *host);
+	bool (*get_interface) (kernel_interface_t *this, host_t *host, char **name);
 
 	/**
 	 * Creates an enumerator over all local addresses.

src/libhydra/kernel/kernel_net.h

@@ -68,9 +68,10 @@ struct kernel_net_t {
 	 * Get the interface name of a local address.
 	 *
 	 * @param host			address to get interface name from
-	 * @return				allocated interface name, or NULL if not found
+	 * @param name			allocated interface name (optional)
+	 * @return				TRUE if interface found and usable
 	 */
-	char* (*get_interface) (kernel_net_t *this, host_t *host);
+	bool (*get_interface) (kernel_net_t *this, host_t *host, char **name);
 
 	/**
 	 * Creates an enumerator over all local addresses.

src/libhydra/plugins/kernel_klips/kernel_klips_ipsec.c

@@ -2108,7 +2108,7 @@ METHOD(kernel_ipsec_t, add_policy, status_t,
 	 */
 	if (policy->route == NULL && direction == POLICY_OUT)
 	{
-		char *iface;
+		char *iface = NULL;
 		ipsec_dev_t *dev;
 		route_entry_t *route = malloc_thing(route_entry_t);
 		route->src_ip = NULL;
@@ -2126,8 +2126,8 @@ METHOD(kernel_ipsec_t, add_policy, status_t,
 		}
 
 		/* find the virtual interface */
-		iface = hydra->kernel_interface->get_interface(hydra->kernel_interface,
+		hydra->kernel_interface->get_interface(hydra->kernel_interface,
-													   src);
+											   src, &iface);
 		if (find_ipsec_dev(this, iface, &dev) == SUCCESS)
 		{
 			/* above, we got either the name of a virtual or a physical

src/libhydra/plugins/kernel_netlink/kernel_netlink_ipsec.c

@@ -2169,14 +2169,13 @@ static status_t add_policy_internal(private_kernel_netlink_ipsec_t *this,
 			route->gateway = hydra->kernel_interface->get_nexthop(
 											hydra->kernel_interface, ipsec->src,
 											ipsec->dst);
-			/* install route via outgoing interface */
-			route->if_name = hydra->kernel_interface->get_interface(
-										hydra->kernel_interface, ipsec->dst);
 			route->dst_net = chunk_alloc(policy->sel.family == AF_INET ? 4 : 16);
 			memcpy(route->dst_net.ptr, &policy->sel.saddr, route->dst_net.len);
 			route->prefixlen = policy->sel.prefixlen_s;
 
-			if (!route->if_name)
+			/* install route via outgoing interface */
+			if (!hydra->kernel_interface->get_interface(hydra->kernel_interface,
+												ipsec->dst, &route->if_name))
 			{
 				this->mutex->unlock(this->mutex);
 				route_entry_destroy(route);

src/libhydra/plugins/kernel_netlink/kernel_netlink_net.c

@@ -365,13 +365,15 @@ static job_requeue_t reinstall_routes(private_kernel_netlink_net_t *this)
 		change = this->net_changes->get(this->net_changes, &lookup);
 		if (!change)
 		{	/* in case src_ip is not on the outgoing interface */
-			lookup.if_name = this->public.interface.get_interface(
+			if (this->public.interface.get_interface(&this->public.interface,
-										&this->public.interface, route->src_ip);
+												route->src_ip, &lookup.if_name))
-			if (lookup.if_name && !streq(lookup.if_name, route->if_name))
 			{
-				change = this->net_changes->get(this->net_changes, &lookup);
+				if (!streq(lookup.if_name, route->if_name))
+				{
+					change = this->net_changes->get(this->net_changes, &lookup);
+				}
+				free(lookup.if_name);
 			}
-			free(lookup.if_name);
 		}
 		if (change)
 		{
@@ -999,15 +1001,13 @@ METHOD(kernel_net_t, create_address_enumerator, enumerator_t*,
 				(void*)address_enumerator_destroy);
 }
 
-METHOD(kernel_net_t, get_interface_name, char*,
+METHOD(kernel_net_t, get_interface_name, bool,
-	private_kernel_netlink_net_t *this, host_t* ip)
+	private_kernel_netlink_net_t *this, host_t* ip, char **name)
 {
 	enumerator_t *ifaces, *addrs;
 	iface_entry_t *iface;
 	addr_entry_t *addr;
-	char *name = NULL;
+	bool found = FALSE;
-
-	DBG2(DBG_KNL, "getting interface name for %H", ip);
 
 	this->mutex->lock(this->mutex);
 	ifaces = this->ifaces->create_enumerator(this->ifaces);
@@ -1018,12 +1018,16 @@ METHOD(kernel_net_t, get_interface_name, char*,
 		{
 			if (ip->ip_equals(ip, addr->ip))
 			{
-				name = strdup(iface->ifname);
+				found = TRUE;
+				if (name)
+				{
+					*name = strdup(iface->ifname);
+				}
 				break;
 			}
 		}
 		addrs->destroy(addrs);
-		if (name)
+		if (found)
 		{
 			break;
 		}
@@ -1031,15 +1035,15 @@ METHOD(kernel_net_t, get_interface_name, char*,
 	ifaces->destroy(ifaces);
 	this->mutex->unlock(this->mutex);
 
-	if (name)
+	if (!found)
-	{
-		DBG2(DBG_KNL, "%H is on interface %s", ip, name);
-	}
-	else
 	{
 		DBG2(DBG_KNL, "%H is not a local address", ip);
 	}
-	return name;
+	else if (name)
+	{
+		DBG2(DBG_KNL, "%H is on interface %s", ip, *name);
+	}
+	return found;
 }
 
 /**

src/libhydra/plugins/kernel_pfkey/kernel_pfkey_ipsec.c

@@ -2028,14 +2028,13 @@ static status_t add_policy_internal(private_kernel_pfkey_ipsec_t *this,
 			route->gateway = hydra->kernel_interface->get_nexthop(
 											hydra->kernel_interface, ipsec->src,
 											ipsec->dst);
-			/* install route via outgoing interface */
-			route->if_name = hydra->kernel_interface->get_interface(
-										hydra->kernel_interface, ipsec->dst);
 			route->dst_net = chunk_clone(policy->src.net->get_address(
 											policy->src.net));
 			route->prefixlen = policy->src.mask;
 
-			if (!route->if_name)
+			/* install route via outgoing interface */
+			if (!hydra->kernel_interface->get_interface(hydra->kernel_interface,
+												ipsec->dst, &route->if_name))
 			{
 				this->mutex->unlock(this->mutex);
 				route_entry_destroy(route);

src/libhydra/plugins/kernel_pfroute/kernel_pfroute_net.c

@@ -472,15 +472,13 @@ METHOD(kernel_net_t, create_address_enumerator, enumerator_t*,
 				(void*)address_enumerator_destroy);
 }
 
-METHOD(kernel_net_t, get_interface_name, char*,
+METHOD(kernel_net_t, get_interface_name, bool,
-	private_kernel_pfroute_net_t *this, host_t* ip)
+	private_kernel_pfroute_net_t *this, host_t* ip, char **name)
 {
 	enumerator_t *ifaces, *addrs;
 	iface_entry_t *iface;
 	addr_entry_t *addr;
-	char *name = NULL;
+	bool found = FALSE;
-
-	DBG2(DBG_KNL, "getting interface name for %H", ip);
 
 	this->mutex->lock(this->mutex);
 	ifaces = this->ifaces->create_enumerator(this->ifaces);
@@ -491,12 +489,16 @@ METHOD(kernel_net_t, get_interface_name, char*,
 		{
 			if (ip->ip_equals(ip, addr->ip))
 			{
-				name = strdup(iface->ifname);
+				found = TRUE;
+				if (name)
+				{
+					*name = strdup(iface->ifname);
+				}
 				break;
 			}
 		}
 		addrs->destroy(addrs);
-		if (name)
+		if (found)
 		{
 			break;
 		}
@@ -504,15 +506,15 @@ METHOD(kernel_net_t, get_interface_name, char*,
 	ifaces->destroy(ifaces);
 	this->mutex->unlock(this->mutex);
 
-	if (name)
+	if (!found)
-	{
-		DBG2(DBG_KNL, "%H is on interface %s", ip, name);
-	}
-	else
 	{
 		DBG2(DBG_KNL, "%H is not a local address", ip);
 	}
-	return name;
+	else if (name)
+	{
+		DBG2(DBG_KNL, "%H is on interface %s", ip, *name);
+	}
+	return found;
 }
 
 METHOD(kernel_net_t, get_source_addr, host_t*,