sgsn: Moved IMSI ACL management to sgsn_auth.c

Currently the ACL code is located in sgsn_vty.c.

This commit moves this to a new file sgsn_auth.c as a first step to
make authorization more flexible in order to implement remote
acquisition on subsciber data.

Sponsored-by: On-Waves ehf
diff --git a/openbsc/src/gprs/sgsn_auth.c b/openbsc/src/gprs/sgsn_auth.c
new file mode 100644
index 0000000..0a85934
--- /dev/null
+++ b/openbsc/src/gprs/sgsn_auth.c
@@ -0,0 +1,71 @@
+/* MS authorization and subscriber data handling */
+
+/* (C) 2009-2010 by Harald Welte <laforge@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <openbsc/sgsn.h>
+#include <openbsc/gprs_sgsn.h>
+
+void sgsn_auth_init(struct sgsn_instance *sgi)
+{
+	INIT_LLIST_HEAD(&sgi->cfg.imsi_acl);
+}
+
+/* temporary IMSI ACL hack */
+struct imsi_acl_entry *sgsn_acl_lookup(const char *imsi, struct sgsn_config *cfg)
+{
+	struct imsi_acl_entry *acl;
+	llist_for_each_entry(acl, &cfg->imsi_acl, list) {
+		if (!strcmp(imsi, acl->imsi))
+			return acl;
+	}
+	return NULL;
+}
+
+int sgsn_acl_add(const char *imsi, struct sgsn_config *cfg)
+{
+	struct imsi_acl_entry *acl;
+
+	if (sgsn_acl_lookup(imsi, cfg))
+		return -EEXIST;
+
+	acl = talloc_zero(NULL, struct imsi_acl_entry);
+	if (!acl)
+		return -ENOMEM;
+	strncpy(acl->imsi, imsi, sizeof(acl->imsi));
+
+	llist_add(&acl->list, &cfg->imsi_acl);
+
+	return 0;
+}
+
+int sgsn_acl_del(const char *imsi, struct sgsn_config *cfg)
+{
+	struct imsi_acl_entry *acl;
+
+	acl = sgsn_acl_lookup(imsi, cfg);
+	if (!acl)
+		return -ENODEV;
+
+	llist_del(&acl->list);
+	talloc_free(acl);
+
+	return 0;
+}
+