osmo-epdg: fill attributes INTERNAL_DNS and P_CSCF_IP4_ADDRESS

In order to get a pixel7a connecting to the ePDG.
Add the remaining code so PCOs could be added later.

src/libcharon/plugins/osmo_epdg/osmo_epdg_provider.c

@@ -23,6 +23,7 @@
 #include "osmo_epdg_ue.h"
 
 #include <daemon.h>
+#include <collections/linked_list.h>
 #include <credentials/keys/shared_key.h>
 #include <osmocom/gsm/apn.h>
 #include <osmocom/gsm/protocol/gsm_04_08_gprs.h>
@@ -199,13 +200,55 @@ METHOD(attribute_provider_t, release_address, bool,
 	return found;
 }
 
+/* see attr_provider for similar usage */
+CALLBACK(attribute_enum_filter, bool,
+        void *data, enumerator_t *orig, va_list args)
+{
+	osmo_epdg_attribute_t *entry;
+	configuration_attribute_type_t *type;
+	chunk_t *value;
+
+	VA_ARGS_VGET(args, type, value);
+	while (orig->enumerate(orig, &entry))
+	{
+		if (entry->valid)
+		{
+			*type = entry->type;
+			*value = entry->value;
+			return TRUE;
+		}
+	}
+
+	return FALSE;
+}
+
 METHOD(attribute_provider_t, create_attribute_enumerator, enumerator_t*,
 	private_osmo_epdg_provider_t *this, linked_list_t *pools, ike_sa_t *ike_sa,
 	linked_list_t *vips)
 {
-	/* don't forget fixing the this point if needed */
-	/* no additional attributes for this ike_sa */
-	return enumerator_create_empty();
+	this = container_of((void *) this, private_osmo_epdg_provider_t, public.attribute);
+	enumerator_t *enumerator = NULL;
+	linked_list_t *attributes = NULL;
+	osmo_epdg_ue_t *ue = this->db->get_subscriber_ike(this->db, ike_sa);
+
+	/* create an iterator based on the llist */
+	if (!ue)
+	{
+		return enumerator_create_empty();
+	}
+
+	/* this ref is giving into the enumerator */
+	ue->get(ue);
+	attributes = ue->get_attributes(ue);
+	enumerator = enumerator_create_cleaner(
+			enumerator_create_filter(
+				attributes->create_enumerator(attributes),
+				attribute_enum_filter, NULL, NULL),
+			(void *)ue->put, ue);
+
+	/* this ref was taken by get_subscriber */
+	ue->put(ue);
+	return enumerator;
 }
 
 METHOD(osmo_epdg_provider_t, destroy, void,

src/libcharon/plugins/osmo_epdg/osmo_epdg_ue.c

@@ -20,6 +20,7 @@
 
 #include <sa/ike_sa.h>
 #include <threading/rwlock.h>
+#include <collections/linked_list.h>
 #include <utils/utils.h>
 #include <utils/debug.h>
 
@@ -59,6 +60,13 @@ struct private_osmo_epdg_ue_t {
 	 */
 	host_t *address;
 
+	/**
+	 * The requested attributes/PCO options on GTP
+	 * e.g. P-CSCF requests, DNS, ..
+	 * holds attribute_entry_t
+	 */
+	linked_list_t *attributes;
+
 	/**
 	 * Refcount to track this object.
 	 * It will call destroy() when refcount reaches 0
@@ -145,6 +153,13 @@ METHOD(osmo_epdg_ue_t, get_state, enum osmo_epdg_ue_state,
 	return state;
 }
 
+METHOD(osmo_epdg_ue_t, get_attributes, linked_list_t *,
+       private_osmo_epdg_ue_t *this)
+{
+	/* TODO: check if we need to also take locking .. also refcounting would be great here */
+	return this->attributes;
+}
+
 METHOD(osmo_epdg_ue_t, get, void,
        private_osmo_epdg_ue_t *this)
 {
@@ -160,10 +175,23 @@ METHOD(osmo_epdg_ue_t, put, void,
 	}
 }
 
+
+CALLBACK(destroy_attribute, void,
+	osmo_epdg_attribute_t *attr)
+{
+	if (attr->valid)
+	{
+		chunk_free(&attr->value);
+	}
+	free(attr);
+}
+
 METHOD(osmo_epdg_ue_t, destroy, void,
        private_osmo_epdg_ue_t *this)
 {
 	this->lock->destroy(this->lock);
+	this->attributes->destroy_function(this->attributes, destroy_attribute);
+
 	free(this->apn);
 	free(this->imsi);
 	free(this);
@@ -191,6 +219,7 @@ osmo_epdg_ue_t *osmo_epdg_ue_create(uint32_t id, const char *imsi, const char *a
 		 .set_address = _set_address,
 		 .get_state = _get_state,
 		 .set_state = _set_state,
+		 .get_attributes = _get_attributes,
 		 .destroy = _destroy,
 	     },
 	     .apn = strdup(apn),
@@ -198,8 +227,27 @@ osmo_epdg_ue_t *osmo_epdg_ue_create(uint32_t id, const char *imsi, const char *a
 	     .id = id,
 	     .lock = rwlock_create(RWLOCK_TYPE_DEFAULT),
 	     .state = UE_WAIT_LOCATION_UPDATE,
+	     .attributes = linked_list_create(),
 	     .refcount = 1,
 	     );
 
+	/* hardcode P-CSCF and DNS entry */
+	osmo_epdg_attribute_t *entry;
+	host_t *host = host_create_from_string_and_family("10.74.0.31", AF_INET, 0);
+	INIT(entry,
+		.type = INTERNAL_IP4_DNS,
+		.value = chunk_clone(host->get_address(host)),
+		.valid = TRUE,
+	);
+	this->attributes->insert_last(this->attributes, entry);
+
+	INIT(entry,
+		.type = P_CSCF_IP4_ADDRESS,
+		.value = chunk_clone(host->get_address(host)),
+		.valid = TRUE,
+	);
+	this->attributes->insert_last(this->attributes, entry);
+	host->destroy(host);
+
 	return &this->public;
 }

src/libcharon/plugins/osmo_epdg/osmo_epdg_ue.h

@@ -79,6 +79,11 @@ struct osmo_epdg_ue_t {
 	 */
 	void (*set_id)(osmo_epdg_ue_t *this, uint32_t unique_id);
 
+	/**
+	 * Get Linked list of osmo_epdg_attribute_t
+	 */
+	linked_list_t *(*get_attributes)(osmo_epdg_ue_t *this);
+
 	/**
 	 * Get address. Returns NULL or a cloned' host_t object
 	 */
@@ -117,6 +122,13 @@ struct osmo_epdg_ue_t {
 	void (*destroy)(osmo_epdg_ue_t *this);
 };
 
+struct osmo_epdg_attribute_t {
+	configuration_attribute_type_t type;
+	chunk_t value;
+	bool valid;
+};
+typedef struct osmo_epdg_attribute_t osmo_epdg_attribute_t;
+
 /**
  * Create a osmo_epdg_ue instance.
  * A newly created object will come with refcount = 1. Use put() to destroy it.