diff --git a/openbsc/configure.ac b/openbsc/configure.ac
index 00d1b70..394972f 100644
--- a/openbsc/configure.ac
+++ b/openbsc/configure.ac
@@ -179,6 +179,7 @@
     src/libmsc/Makefile
     src/libmgcp/Makefile
     src/libcommon/Makefile
+    src/libfilter/Makefile
     src/osmo-nitb/Makefile
     src/osmo-bsc/Makefile
     src/osmo-bsc_nat/Makefile
diff --git a/openbsc/doc/examples/osmo-bsc/osmo-bsc.cfg b/openbsc/doc/examples/osmo-bsc/osmo-bsc.cfg
index d746196..fd4c3d7 100644
--- a/openbsc/doc/examples/osmo-bsc/osmo-bsc.cfg
+++ b/openbsc/doc/examples/osmo-bsc/osmo-bsc.cfg
@@ -98,3 +98,8 @@
  timeout-ping 20
  timeout-pong 5
  dest 192.168.100.11 6666 0
+ access-list-name msc-list
+ no access-list-name
+bsc
+ no access-list-name
+ access-list-name bsc-list
diff --git a/openbsc/include/openbsc/Makefile.am b/openbsc/include/openbsc/Makefile.am
index d2b30de..254f43d 100644
--- a/openbsc/include/openbsc/Makefile.am
+++ b/openbsc/include/openbsc/Makefile.am
@@ -16,7 +16,7 @@
 		arfcn_range_encode.h nat_rewrite_trie.h bsc_nat_callstats.h \
 		osmux.h mgcp_transcode.h gprs_utils.h \
 		 gprs_gb_parse.h smpp.h meas_feed.h gprs_gsup_messages.h \
-		 gprs_gsup_client.h
+		 gprs_gsup_client.h bsc_msg_filter.h
 
 openbsc_HEADERS = gsm_04_08.h meas_rep.h bsc_api.h
 openbscdir = $(includedir)/openbsc
diff --git a/openbsc/include/openbsc/bsc_msg_filter.h b/openbsc/include/openbsc/bsc_msg_filter.h
new file mode 100644
index 0000000..a9dedf4
--- /dev/null
+++ b/openbsc/include/openbsc/bsc_msg_filter.h
@@ -0,0 +1,107 @@
+#pragma once
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/msgfile.h>
+#include <osmocom/core/linuxrbtree.h>
+#include <osmocom/core/linuxlist.h>
+
+#include <regex.h>
+
+struct vty;
+struct gsm48_hdr;
+
+struct bsc_filter_reject_cause {
+	int lu_reject_cause;
+	int cm_reject_cause;
+};
+
+struct bsc_filter_barr_entry {
+	struct rb_node node;
+
+	char *imsi;
+	int cm_reject_cause;
+	int lu_reject_cause;
+};
+
+enum bsc_filter_acc_ctr {
+	ACC_LIST_LOCAL_FILTER,
+	ACC_LIST_GLOBAL_FILTER,
+};
+
+struct bsc_msg_acc_lst {
+	struct llist_head list;
+
+	/* counter */
+	struct rate_ctr_group *stats;
+
+	/* the name of the list */
+	const char *name;
+	struct llist_head fltr_list;
+};
+
+struct bsc_msg_acc_lst_entry {
+	struct llist_head list;
+
+	/* the filter */
+	char *imsi_allow;
+	regex_t imsi_allow_re;
+	char *imsi_deny;
+	regex_t imsi_deny_re;
+
+	/* reject reasons for the access lists */
+	int cm_reject_cause;
+	int lu_reject_cause;
+};
+
+enum {
+	FLT_CON_TYPE_NONE,
+	FLT_CON_TYPE_LU,
+	FLT_CON_TYPE_CM_SERV_REQ,
+	FLT_CON_TYPE_PAG_RESP,
+	FLT_CON_TYPE_SSA,
+	FLT_CON_TYPE_LOCAL_REJECT,
+	FLT_CON_TYPE_OTHER,
+};
+
+
+struct bsc_filter_state {
+	char *imsi;
+	int imsi_checked;
+	int con_type;
+};
+
+struct bsc_filter_request {
+	void *ctx;
+	struct rb_root *black_list;
+	struct llist_head *access_lists;
+	const char *local_lst_name;
+	const char *global_lst_name;
+	int bsc_nr;
+};
+
+
+int bsc_filter_barr_adapt(void *ctx, struct rb_root *rbtree, const struct osmo_config_list *);
+int bsc_filter_barr_find(struct rb_root *root, const char *imsi, int *cm, int *lu);
+
+/**
+ * Content filtering.
+ */
+int bsc_msg_filter_initial(struct gsm48_hdr *hdr, size_t size,
+			struct bsc_filter_request *req,
+			int *con_type, char **imsi,
+			struct bsc_filter_reject_cause *cause);
+int bsc_msg_filter_data(struct gsm48_hdr *hdr, size_t size,
+			struct bsc_filter_request *req,
+			struct bsc_filter_state *state,
+			struct bsc_filter_reject_cause *cause);
+
+/* IMSI allow/deny handling */
+struct bsc_msg_acc_lst *bsc_msg_acc_lst_find(struct llist_head *lst, const char *name);
+struct bsc_msg_acc_lst *bsc_msg_acc_lst_get(void *ctx, struct llist_head *lst, const char *name);
+void bsc_msg_acc_lst_delete(struct bsc_msg_acc_lst *lst);
+
+struct bsc_msg_acc_lst_entry *bsc_msg_acc_lst_entry_create(struct bsc_msg_acc_lst *);
+int bsc_msg_acc_lst_check_allow(struct bsc_msg_acc_lst *lst, const char *imsi);
+
+void bsc_msg_lst_vty_init(void *ctx, struct llist_head *lst, int node);
+void bsc_msg_acc_lst_write(struct vty *vty, struct bsc_msg_acc_lst *lst);
diff --git a/openbsc/include/openbsc/bsc_nat.h b/openbsc/include/openbsc/bsc_nat.h
index 19144e3..ae940b3 100644
--- a/openbsc/include/openbsc/bsc_nat.h
+++ b/openbsc/include/openbsc/bsc_nat.h
@@ -22,6 +22,7 @@
 #define BSC_NAT_H
 
 #include "mgcp.h"
+#include "bsc_msg_filter.h"
 
 
 #include <osmocom/core/select.h>
@@ -47,16 +48,6 @@
 struct bsc_nat_ussd_con;
 struct nat_rewrite_rule;
 
-enum {
-	NAT_CON_TYPE_NONE,
-	NAT_CON_TYPE_LU,
-	NAT_CON_TYPE_CM_SERV_REQ,
-	NAT_CON_TYPE_PAG_RESP,
-	NAT_CON_TYPE_SSA,
-	NAT_CON_TYPE_LOCAL_REJECT,
-	NAT_CON_TYPE_OTHER,
-};
-
 /*
  * Is this terminated to the MSC, to the local machine (release
  * handling for IMSI filtering) or to a USSD provider?
@@ -229,36 +220,6 @@
 	} ussd;
 };
 
-enum bsc_nat_acc_ctr {
-	ACC_LIST_BSC_FILTER,
-	ACC_LIST_NAT_FILTER,
-};
-
-struct bsc_nat_acc_lst {
-	struct llist_head list;
-
-	/* counter */
-	struct rate_ctr_group *stats;
-
-	/* the name of the list */
-	const char *name;
-	struct llist_head fltr_list;
-};
-
-struct bsc_nat_acc_lst_entry {
-	struct llist_head list;
-
-	/* the filter */
-	char *imsi_allow;
-	regex_t imsi_allow_re;
-	char *imsi_deny;
-	regex_t imsi_deny_re;
-
-	/* reject reasons for the access lists */
-	int cm_reject_cause;
-	int lu_reject_cause;
-};
-
 /**
  * the structure of the "nat" network
  */
@@ -355,11 +316,6 @@
 	struct osmo_timer_list auth_timeout;
 };
 
-struct bsc_nat_reject_cause {
-	int lu_reject_cause;
-	int cm_reject_cause;
-};
-
 /* create and init the structures */
 struct bsc_config *bsc_config_alloc(struct bsc_nat *nat, const char *token);
 struct bsc_config *bsc_config_num(struct bsc_nat *nat, int num);
@@ -390,16 +346,6 @@
 int bsc_nat_find_paging(struct msgb *msg, const uint8_t **,int *len);
 
 /**
- * Content filtering.
- */
-int bsc_nat_filter_sccp_cr(struct bsc_connection *bsc, struct msgb *msg,
-			struct bsc_nat_parsed *, int *con_type, char **imsi,
-			struct bsc_nat_reject_cause *cause);
-int bsc_nat_filter_dt(struct bsc_connection *bsc, struct msgb *msg,
-			struct nat_sccp_connection *con, struct bsc_nat_parsed *parsed,
-			struct bsc_nat_reject_cause *cause);
-
-/**
  * SCCP patching and handling
  */
 struct nat_sccp_connection *create_sccp_src_ref(struct bsc_connection *bsc, struct bsc_nat_parsed *parsed);
@@ -435,14 +381,6 @@
 int bsc_write_msg(struct osmo_wqueue *queue, struct msgb *msg);
 int bsc_write_cb(struct osmo_fd *bfd, struct msgb *msg);
 
-/* IMSI allow/deny handling */
-struct bsc_nat_acc_lst *bsc_nat_acc_lst_find(struct bsc_nat *nat, const char *name);
-struct bsc_nat_acc_lst *bsc_nat_acc_lst_get(struct bsc_nat *nat, const char *name);
-void bsc_nat_acc_lst_delete(struct bsc_nat_acc_lst *lst);
-
-struct bsc_nat_acc_lst_entry *bsc_nat_acc_lst_entry_create(struct bsc_nat_acc_lst *);
-int bsc_nat_lst_check_allow(struct bsc_nat_acc_lst *lst, const char *imsi);
-
 int bsc_nat_msc_is_connected(struct bsc_nat *nat);
 
 int bsc_conn_type_to_ctr(struct nat_sccp_connection *conn);
@@ -478,17 +416,6 @@
 
 void bsc_nat_num_rewr_entry_adapt(void *ctx, struct llist_head *head, const struct osmo_config_list *);
 
-struct bsc_nat_barr_entry {
-	struct rb_node node;
-
-	char *imsi;
-	int cm_reject_cause;
-	int lu_reject_cause;
-};
-
-int bsc_nat_barr_adapt(void *ctx, struct rb_root *rbtree, const struct osmo_config_list *);
-int bsc_nat_barr_find(struct rb_root *root, const char *imsi, int *cm, int *lu);
-
 void bsc_nat_send_mgcp_to_msc(struct bsc_nat *bsc_nat, struct msgb *msg);
 void bsc_nat_handle_mgcp(struct bsc_nat *bsc, struct msgb *msg);
 
@@ -499,6 +426,13 @@
 int bsc_nat_extract_lac(struct bsc_connection *bsc, struct nat_sccp_connection *con,
 				struct bsc_nat_parsed *parsed, struct msgb *msg);
 
+int bsc_nat_filter_sccp_cr(struct bsc_connection *bsc, struct msgb *msg,
+			struct bsc_nat_parsed *, int *con_type, char **imsi,
+			struct bsc_filter_reject_cause *cause);
+int bsc_nat_filter_dt(struct bsc_connection *bsc, struct msgb *msg,
+			struct nat_sccp_connection *con, struct bsc_nat_parsed *parsed,
+			struct bsc_filter_reject_cause *cause);
+
 /**
  * CTRL interface helper
  */
diff --git a/openbsc/include/openbsc/bsc_nat_sccp.h b/openbsc/include/openbsc/bsc_nat_sccp.h
index 0561df1..0824664 100644
--- a/openbsc/include/openbsc/bsc_nat_sccp.h
+++ b/openbsc/include/openbsc/bsc_nat_sccp.h
@@ -22,6 +22,8 @@
 #ifndef BSC_NAT_SCCP_H
 #define BSC_NAT_SCCP_H
 
+#include "bsc_msg_filter.h"
+
 #include <osmocom/sccp/sccp_types.h>
 
 /*
@@ -77,11 +79,10 @@
 	int has_remote_ref;
 
 	/* status */
-	int con_type;
 	int con_local;
 	int authorized;
-	int imsi_checked;
-	char *imsi;
+
+	struct bsc_filter_state filter_state;
 
 	uint16_t lac;
 	uint16_t ci;
diff --git a/openbsc/include/openbsc/debug.h b/openbsc/include/openbsc/debug.h
index bbb3ee6..19d8fc2 100644
--- a/openbsc/include/openbsc/debug.h
+++ b/openbsc/include/openbsc/debug.h
@@ -32,6 +32,7 @@
 	DNAT,
 	DCTRL,
 	DSMPP,
+	DFILTER,
 	Debug_LastEntry,
 };
 
diff --git a/openbsc/include/openbsc/osmo_bsc.h b/openbsc/include/openbsc/osmo_bsc.h
index 19b879f..fd5303d 100644
--- a/openbsc/include/openbsc/osmo_bsc.h
+++ b/openbsc/include/openbsc/osmo_bsc.h
@@ -4,6 +4,7 @@
 #define OSMO_BSC_H
 
 #include "bsc_api.h"
+#include "bsc_msg_filter.h"
 
 #define BSS_SEND_USSD 1
 
@@ -41,6 +42,8 @@
 
 	struct gsm_subscriber_connection *conn;
 	uint8_t new_subscriber;
+
+	struct bsc_filter_state filter_state;
 };
 
 struct bsc_api *osmo_bsc_api();
@@ -63,4 +66,6 @@
 
 void bsc_gen_location_state_trap(struct gsm_bts *bts);
 
+struct llist_head *bsc_access_lists(void);
+
 #endif
diff --git a/openbsc/include/openbsc/osmo_msc_data.h b/openbsc/include/openbsc/osmo_msc_data.h
index bdc762a..2d863aa 100644
--- a/openbsc/include/openbsc/osmo_msc_data.h
+++ b/openbsc/include/openbsc/osmo_msc_data.h
@@ -92,6 +92,8 @@
 
 	/* ussd text when MSC has entered the grace period */
 	char *ussd_grace_txt;
+
+	char *acc_lst_name;
 };
 
 /*
@@ -112,6 +114,8 @@
 
 	/* ussd text when there is no MSC available */
 	char *ussd_no_msc_txt;
+
+	char *acc_lst_name;
 };
 
 
diff --git a/openbsc/src/Makefile.am b/openbsc/src/Makefile.am
index db7603b..6f6174e 100644
--- a/openbsc/src/Makefile.am
+++ b/openbsc/src/Makefile.am
@@ -2,7 +2,7 @@
 AM_CFLAGS=-Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBOSMOVTY_CFLAGS) $(COVERAGE_CFLAGS)
 AM_LDFLAGS = $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS) $(COVERAGE_LDFLAGS)
 
-SUBDIRS = libcommon libmgcp libbsc libmsc libtrau osmo-nitb osmo-bsc_mgcp utils ipaccess gprs
+SUBDIRS = libcommon libmgcp libbsc libmsc libtrau libfilter osmo-nitb osmo-bsc_mgcp utils ipaccess gprs
 
 # Conditional modules
 if BUILD_NAT
diff --git a/openbsc/src/libcommon/debug.c b/openbsc/src/libcommon/debug.c
index ca7ff5d..7fb3ecb 100644
--- a/openbsc/src/libcommon/debug.c
+++ b/openbsc/src/libcommon/debug.c
@@ -160,6 +160,11 @@
 		.description = "SMPP interface for external SMS apps",
 		.enabled = 1, .loglevel = LOGL_DEBUG,
 	},
+	[DFILTER] = {
+		.name = "DFILTER",
+		.description = "BSC/NAT IMSI based filtering",
+		.enabled = 1, .loglevel = LOGL_DEBUG,
+	},
 };
 
 enum log_filter {
diff --git a/openbsc/src/libfilter/Makefile.am b/openbsc/src/libfilter/Makefile.am
new file mode 100644
index 0000000..4dbc590
--- /dev/null
+++ b/openbsc/src/libfilter/Makefile.am
@@ -0,0 +1,11 @@
+AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include -I$(top_builddir)
+AM_CFLAGS=-Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) \
+	$(LIBOSMOVTY_CFLAGS) $(LIBOSMOABIS_CFLAGS) $(COVERAGE_CFLAGS)
+
+noinst_LIBRARIES = libfilter.a
+
+libfilter_a_SOURCES = \
+	bsc_msg_filter.c \
+	bsc_msg_acc.c \
+	bsc_msg_vty.c
+
diff --git a/openbsc/src/libfilter/bsc_msg_acc.c b/openbsc/src/libfilter/bsc_msg_acc.c
new file mode 100644
index 0000000..6258b35
--- /dev/null
+++ b/openbsc/src/libfilter/bsc_msg_acc.c
@@ -0,0 +1,116 @@
+/*
+ * (C) 2010-2015 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2010-2011 by On-Waves
+ * 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/bsc_msg_filter.h>
+#include <openbsc/bsc_nat.h>
+
+#include <osmocom/core/rate_ctr.h>
+
+#include <string.h>
+
+static const struct rate_ctr_desc acc_list_ctr_description[] = {
+	[ACC_LIST_LOCAL_FILTER]	= { "access-list.local-filter", "Rejected by rule for local"},
+	[ACC_LIST_GLOBAL_FILTER]= { "access-list.global-filter", "Rejected by rule for global"},
+};
+
+static const struct rate_ctr_group_desc bsc_cfg_acc_list_desc = {
+	.group_name_prefix = "nat.filter",
+	.group_description = "NAT Access-List Statistics",
+	.num_ctr = ARRAY_SIZE(acc_list_ctr_description),
+	.ctr_desc = acc_list_ctr_description,
+};
+
+
+int bsc_msg_acc_lst_check_allow(struct bsc_msg_acc_lst *lst, const char *mi_string)
+{
+	struct bsc_msg_acc_lst_entry *entry;
+
+	llist_for_each_entry(entry, &lst->fltr_list, list) {
+		if (!entry->imsi_allow)
+			continue;
+		if (regexec(&entry->imsi_allow_re, mi_string, 0, NULL, 0) == 0)
+			return 0;
+	}
+
+	return 1;
+}
+
+struct bsc_msg_acc_lst *bsc_msg_acc_lst_find(struct llist_head *head, const char *name)
+{
+	struct bsc_msg_acc_lst *lst;
+
+	if (!name)
+		return NULL;
+
+	llist_for_each_entry(lst, head, list)
+		if (strcmp(lst->name, name) == 0)
+			return lst;
+
+	return NULL;
+}
+
+struct bsc_msg_acc_lst *bsc_msg_acc_lst_get(void *ctx, struct llist_head *head, const char *name)
+{
+	struct bsc_msg_acc_lst *lst;
+
+	lst = bsc_msg_acc_lst_find(head, name);
+	if (lst)
+		return lst;
+
+	lst = talloc_zero(ctx, struct bsc_msg_acc_lst);
+	if (!lst) {
+		LOGP(DNAT, LOGL_ERROR, "Failed to allocate access list");
+		return NULL;
+	}
+
+	/* TODO: get the index right */
+	lst->stats = rate_ctr_group_alloc(lst, &bsc_cfg_acc_list_desc, 0);
+	if (!lst->stats) {
+		talloc_free(lst);
+		return NULL;
+	}
+
+	INIT_LLIST_HEAD(&lst->fltr_list);
+	lst->name = talloc_strdup(lst, name);
+	llist_add_tail(&lst->list, head);
+	return lst;
+}
+
+void bsc_msg_acc_lst_delete(struct bsc_msg_acc_lst *lst)
+{
+	llist_del(&lst->list);
+	rate_ctr_group_free(lst->stats);
+	talloc_free(lst);
+}
+
+struct bsc_msg_acc_lst_entry *bsc_msg_acc_lst_entry_create(struct bsc_msg_acc_lst *lst)
+{
+	struct bsc_msg_acc_lst_entry *entry;
+
+	entry = talloc_zero(lst, struct bsc_msg_acc_lst_entry);
+	if (!entry)
+		return NULL;
+
+	entry->cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
+	entry->lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
+	llist_add_tail(&entry->list, &lst->fltr_list);
+	return entry;
+}
+
diff --git a/openbsc/src/libfilter/bsc_msg_filter.c b/openbsc/src/libfilter/bsc_msg_filter.c
new file mode 100644
index 0000000..be518a4
--- /dev/null
+++ b/openbsc/src/libfilter/bsc_msg_filter.c
@@ -0,0 +1,401 @@
+/*
+ * Access filtering
+ */
+/*
+ * (C) 2010-2015 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2010-2012 by On-Waves
+ * 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/bsc_msg_filter.h>
+
+#include <openbsc/bsc_nat.h>
+#include <openbsc/bsc_nat_sccp.h>
+#include <openbsc/bsc_msc.h>
+#include <openbsc/gsm_data.h>
+#include <openbsc/debug.h>
+#include <openbsc/ipaccess.h>
+
+#include <osmocom/core/talloc.h>
+#include <osmocom/gsm/gsm0808.h>
+
+#include <osmocom/gsm/protocol/gsm_08_08.h>
+#include <osmocom/gsm/protocol/gsm_04_11.h>
+
+#include <osmocom/sccp/sccp.h>
+
+int bsc_filter_barr_find(struct rb_root *root, const char *imsi, int *cm, int *lu)
+{
+	struct bsc_filter_barr_entry *n;
+	n = rb_entry(root->rb_node, struct bsc_filter_barr_entry, node);
+
+	while (n) {
+		int rc = strcmp(imsi, n->imsi);
+		if (rc == 0) {
+			*cm = n->cm_reject_cause;
+			*lu = n->lu_reject_cause;
+			return 1;
+		}
+
+		n = rb_entry(
+			(rc < 0) ? n->node.rb_left : n->node.rb_right,
+			struct bsc_filter_barr_entry, node);
+	};
+
+	return 0;
+}
+
+static int insert_barr_node(struct bsc_filter_barr_entry *entry, struct rb_root *root)
+{
+	struct rb_node **new = &root->rb_node, *parent = NULL;
+
+	while (*new) {
+		int rc;
+		struct bsc_filter_barr_entry *this;
+		this = rb_entry(*new, struct bsc_filter_barr_entry, node);
+		parent = *new;
+
+		rc = strcmp(entry->imsi, this->imsi);
+		if (rc < 0)
+			new = &((*new)->rb_left);
+		else if (rc > 0)
+			new = &((*new)->rb_right);
+		else {
+			LOGP(DFILTER, LOGL_ERROR,
+				"Duplicate entry for IMSI(%s)\n", entry->imsi);
+			talloc_free(entry);
+			return -1;
+		}
+	}
+
+	rb_link_node(&entry->node, parent, new);
+	rb_insert_color(&entry->node, root);
+	return 0;
+}
+
+int bsc_filter_barr_adapt(void *ctx, struct rb_root *root,
+			const struct osmo_config_list *list)
+{
+	struct osmo_config_entry *cfg_entry;
+	int err = 0;
+
+	/* free the old data */
+	while (!RB_EMPTY_ROOT(root)) {
+		struct rb_node *node = rb_first(root);
+		rb_erase(node, root);
+		talloc_free(node);
+	}
+
+	if (!list)
+		return 0;
+
+	/* now adapt the new list */
+	llist_for_each_entry(cfg_entry, &list->entry, list) {
+		struct bsc_filter_barr_entry *entry;
+		entry = talloc_zero(ctx, struct bsc_filter_barr_entry);
+		if (!entry) {
+			LOGP(DFILTER, LOGL_ERROR,
+				"Allocation of the barr entry failed.\n");
+			continue;
+		}
+
+		entry->imsi = talloc_strdup(entry, cfg_entry->mcc);
+		entry->cm_reject_cause = atoi(cfg_entry->mnc);
+		entry->lu_reject_cause = atoi(cfg_entry->option);
+		err |= insert_barr_node(entry, root);
+	}
+
+	return err;
+}
+
+
+static int lst_check_deny(struct bsc_msg_acc_lst *lst, const char *mi_string,
+			int *cm_cause, int *lu_cause)
+{
+	struct bsc_msg_acc_lst_entry *entry;
+
+	llist_for_each_entry(entry, &lst->fltr_list, list) {
+		if (!entry->imsi_deny)
+			continue;
+		if (regexec(&entry->imsi_deny_re, mi_string, 0, NULL, 0) == 0) {
+			*cm_cause = entry->cm_reject_cause;
+			*lu_cause = entry->lu_reject_cause;
+			return 0;
+		}
+	}
+
+	return 1;
+}
+
+/* apply white/black list */
+static int auth_imsi(struct bsc_filter_request *req,
+		const char *imsi,
+		struct bsc_filter_reject_cause *cause)
+{
+	/*
+	 * Now apply blacklist/whitelist of the BSC and the NAT.
+	 * 1.) Check the global IMSI barr list
+	 * 2.) Allow directly if the IMSI is allowed at the BSC
+	 * 3.) Reject if the IMSI is not allowed at the BSC
+	 * 4.) Reject if the IMSI not allowed at the global level.
+	 * 5.) Allow directly if the IMSI is allowed at the global level
+	 */
+	int cm, lu;
+	struct bsc_msg_acc_lst *nat_lst = NULL;
+	struct bsc_msg_acc_lst *bsc_lst = NULL;
+
+	/* 1. global check for barred imsis */
+	if (req->black_list && bsc_filter_barr_find(req->black_list, imsi, &cm, &lu)) {
+		cause->cm_reject_cause = cm;
+		cause->lu_reject_cause = lu;
+		LOGP(DFILTER, LOGL_DEBUG,
+			"Blocking subscriber IMSI %s with CM: %d LU: %d\n",
+			imsi, cm, lu);
+		return -4;
+	}
+
+
+	bsc_lst = bsc_msg_acc_lst_find(req->access_lists, req->local_lst_name);
+	nat_lst = bsc_msg_acc_lst_find(req->access_lists, req->global_lst_name);
+
+
+	if (bsc_lst) {
+		/* 2. BSC allow */
+		if (bsc_msg_acc_lst_check_allow(bsc_lst, imsi) == 0)
+			return 1;
+
+		/* 3. BSC deny */
+		if (lst_check_deny(bsc_lst, imsi, &cm, &lu) == 0) {
+			LOGP(DFILTER, LOGL_ERROR,
+			     "Filtering %s by imsi_deny on config nr: %d.\n", imsi, req->bsc_nr);
+			rate_ctr_inc(&bsc_lst->stats->ctr[ACC_LIST_LOCAL_FILTER]);
+			cause->cm_reject_cause = cm;
+			cause->lu_reject_cause = lu;
+			return -2;
+		}
+
+	}
+
+	/* 4. NAT deny */
+	if (nat_lst) {
+		if (lst_check_deny(nat_lst, imsi, &cm, &lu) == 0) {
+			LOGP(DFILTER, LOGL_ERROR,
+			     "Filtering %s global imsi_deny on bsc nr: %d.\n", imsi, req->bsc_nr);
+			rate_ctr_inc(&nat_lst->stats->ctr[ACC_LIST_GLOBAL_FILTER]);
+			cause->cm_reject_cause = cm;
+			cause->lu_reject_cause = lu;
+			return -3;
+		}
+	}
+
+	return 1;
+}
+
+static int _cr_check_loc_upd(void *ctx,
+			     uint8_t *data, unsigned int length,
+			     char **imsi)
+{
+	uint8_t mi_type;
+	struct gsm48_loc_upd_req *lu;
+	char mi_string[GSM48_MI_SIZE];
+
+	if (length < sizeof(*lu)) {
+		LOGP(DFILTER, LOGL_ERROR,
+		     "LU does not fit. Length is %d \n", length);
+		return -1;
+	}
+
+	lu = (struct gsm48_loc_upd_req *) data;
+	mi_type = lu->mi[0] & GSM_MI_TYPE_MASK;
+
+	/*
+	 * We can only deal with the IMSI. This will fail for a phone that
+	 * will send the TMSI of a previous network to us.
+	 */
+	if (mi_type != GSM_MI_TYPE_IMSI)
+		return 0;
+
+	gsm48_mi_to_string(mi_string, sizeof(mi_string), lu->mi, lu->mi_len);
+	*imsi = talloc_strdup(ctx, mi_string);
+	return 1;
+}
+
+static int _cr_check_cm_serv_req(void *ctx,
+				 uint8_t *data, unsigned int length,
+				 int *con_type, char **imsi)
+{
+	static const uint32_t classmark_offset =
+				offsetof(struct gsm48_service_request, classmark);
+
+	char mi_string[GSM48_MI_SIZE];
+	uint8_t mi_type;
+	int rc;
+	struct gsm48_service_request *req;
+
+	/* unfortunately in Phase1 the classmark2 length is variable */
+
+	if (length < sizeof(*req)) {
+		LOGP(DFILTER, LOGL_ERROR,
+		     "CM Serv Req does not fit. Length is %d\n", length);
+		return -1;
+	}
+
+	req = (struct gsm48_service_request *) data;
+	if (req->cm_service_type == 0x8)
+		*con_type = FLT_CON_TYPE_SSA;
+	rc = gsm48_extract_mi((uint8_t *) &req->classmark,
+			      length - classmark_offset, mi_string, &mi_type);
+	if (rc < 0) {
+		LOGP(DFILTER, LOGL_ERROR, "Failed to parse the classmark2/mi. error: %d\n", rc);
+		return -1;
+	}
+
+	/* we have to let the TMSI or such pass */
+	if (mi_type != GSM_MI_TYPE_IMSI)
+		return 0;
+
+	*imsi = talloc_strdup(ctx, mi_string);
+	return 1;
+}
+
+static int _cr_check_pag_resp(void *ctx,
+			      uint8_t *data, unsigned int length, char **imsi)
+{
+	struct gsm48_pag_resp *resp;
+	char mi_string[GSM48_MI_SIZE];
+	uint8_t mi_type;
+
+	if (length < sizeof(*resp)) {
+		LOGP(DFILTER, LOGL_ERROR, "PAG RESP does not fit. Length was %d.\n", length);
+		return -1;
+	}
+
+	resp = (struct gsm48_pag_resp *) data;
+	if (gsm48_paging_extract_mi(resp, length, mi_string, &mi_type) < 0) {
+		LOGP(DFILTER, LOGL_ERROR, "Failed to extract the MI.\n");
+		return -1;
+	}
+
+	/* we need to let it pass for now */
+	if (mi_type != GSM_MI_TYPE_IMSI)
+		return 0;
+
+	*imsi = talloc_strdup(ctx, mi_string);
+	return 1;
+}
+
+static int _dt_check_id_resp(struct bsc_filter_request *req,
+			     uint8_t *data, unsigned int length,
+			     struct bsc_filter_state *state,
+			     struct bsc_filter_reject_cause *cause)
+{
+	char mi_string[GSM48_MI_SIZE];
+	uint8_t mi_type;
+
+	if (length < 2) {
+		LOGP(DFILTER, LOGL_ERROR, "mi does not fit.\n");
+		return -1;
+	}
+
+	if (data[0] < length - 1) {
+		LOGP(DFILTER, LOGL_ERROR, "mi length too big.\n");
+		return -2;
+	}
+
+	mi_type = data[1] & GSM_MI_TYPE_MASK;
+	gsm48_mi_to_string(mi_string, sizeof(mi_string), &data[1], data[0]);
+
+	if (mi_type != GSM_MI_TYPE_IMSI)
+		return 0;
+
+	state->imsi_checked = 1;
+	state->imsi = talloc_strdup(req->ctx, mi_string);
+	return auth_imsi(req, mi_string, cause);
+}
+
+
+/* Filter out CR data... */
+int bsc_msg_filter_initial(struct gsm48_hdr *hdr48, size_t hdr48_len,
+			struct bsc_filter_request *req,
+			int *con_type,
+			char **imsi, struct bsc_filter_reject_cause *cause)
+{
+	int ret = 0;
+	uint8_t msg_type, proto;
+
+	*con_type = FLT_CON_TYPE_NONE;
+	cause->cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
+	cause->lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
+	*imsi = NULL;
+
+	proto = hdr48->proto_discr & 0x0f;
+	msg_type = hdr48->msg_type & 0xbf;
+	if (proto == GSM48_PDISC_MM &&
+	    msg_type == GSM48_MT_MM_LOC_UPD_REQUEST) {
+		*con_type = FLT_CON_TYPE_LU;
+		ret = _cr_check_loc_upd(req->ctx, &hdr48->data[0],
+					hdr48_len - sizeof(*hdr48), imsi);
+	} else if (proto == GSM48_PDISC_MM &&
+		  msg_type == GSM48_MT_MM_CM_SERV_REQ) {
+		*con_type = FLT_CON_TYPE_CM_SERV_REQ;
+		ret = _cr_check_cm_serv_req(req->ctx, &hdr48->data[0],
+					     hdr48_len - sizeof(*hdr48),
+					     con_type, imsi);
+	} else if (proto == GSM48_PDISC_RR &&
+		   msg_type == GSM48_MT_RR_PAG_RESP) {
+		*con_type = FLT_CON_TYPE_PAG_RESP;
+		ret = _cr_check_pag_resp(req->ctx, &hdr48->data[0],
+					hdr48_len - sizeof(*hdr48), imsi);
+	} else {
+		/* We only want to filter the above, let other things pass */
+		*con_type = FLT_CON_TYPE_OTHER;
+		return 0;
+	}
+
+	/* check if we are done */
+	if (ret != 1)
+		return ret;
+
+	/* the memory allocation failed */
+	if (!*imsi)
+		return -1;
+
+	/* now check the imsi */
+	return auth_imsi(req, *imsi, cause);
+}
+
+int bsc_msg_filter_data(struct gsm48_hdr *hdr48, size_t len,
+		struct bsc_filter_request *req,
+		struct bsc_filter_state *state,
+		struct bsc_filter_reject_cause *cause)
+{
+	uint8_t msg_type, proto;
+
+	cause->cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
+	cause->lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
+
+	if (state->imsi_checked)
+		return 0;
+
+	proto = hdr48->proto_discr & 0x0f;
+	msg_type = hdr48->msg_type & 0xbf;
+	if (proto != GSM48_PDISC_MM || msg_type != GSM48_MT_MM_ID_RESP)
+		return 0;
+
+	return _dt_check_id_resp(req, &hdr48->data[0],
+					len - sizeof(*hdr48), state, cause);
+}
diff --git a/openbsc/src/libfilter/bsc_msg_vty.c b/openbsc/src/libfilter/bsc_msg_vty.c
new file mode 100644
index 0000000..c342fdc
--- /dev/null
+++ b/openbsc/src/libfilter/bsc_msg_vty.c
@@ -0,0 +1,140 @@
+/* (C) 2010-2015 by Holger Hans Peter Freyther
+ * (C) 2010-2013 by On-Waves
+ * 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/bsc_msg_filter.h>
+#include <openbsc/gsm_data.h>
+#include <openbsc/vty.h>
+
+#include <osmocom/vty/misc.h>
+
+static struct llist_head *_acc_lst;
+static void *_ctx;
+
+DEFUN(cfg_lst_no,
+      cfg_lst_no_cmd,
+      "no access-list NAME",
+      NO_STR "Remove an access-list by name\n"
+      "The access-list to remove\n")
+{
+	struct bsc_msg_acc_lst *acc;
+	acc = bsc_msg_acc_lst_find(_acc_lst, argv[0]);
+	if (!acc)
+		return CMD_WARNING;
+
+	bsc_msg_acc_lst_delete(acc);
+	return CMD_SUCCESS;
+}
+
+DEFUN(show_acc_lst,
+      show_acc_lst_cmd,
+      "show access-list NAME",
+      SHOW_STR "IMSI access list\n" "Name of the access list\n")
+{
+	struct bsc_msg_acc_lst *acc;
+	acc = bsc_msg_acc_lst_find(_acc_lst, argv[0]);
+	if (!acc)
+		return CMD_WARNING;
+
+	vty_out(vty, "access-list %s%s", acc->name, VTY_NEWLINE);
+	vty_out_rate_ctr_group(vty, " ", acc->stats);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_lst_imsi_allow,
+      cfg_lst_imsi_allow_cmd,
+      "access-list NAME imsi-allow [REGEXP]",
+      "Access list commands\n"
+      "Name of the access list\n"
+      "Add allowed IMSI to the list\n"
+      "Regexp for IMSIs\n")
+{
+	struct bsc_msg_acc_lst *acc;
+	struct bsc_msg_acc_lst_entry *entry;
+
+	acc = bsc_msg_acc_lst_get(_ctx, _acc_lst, argv[0]);
+	if (!acc)
+		return CMD_WARNING;
+
+	entry = bsc_msg_acc_lst_entry_create(acc);
+	if (!entry)
+		return CMD_WARNING;
+
+	if (gsm_parse_reg(acc, &entry->imsi_allow_re, &entry->imsi_allow, argc - 1, &argv[1]) != 0)
+		return CMD_WARNING;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_lst_imsi_deny,
+      cfg_lst_imsi_deny_cmd,
+      "access-list NAME imsi-deny [REGEXP] (<0-256>) (<0-256>)",
+      "Access list commands\n"
+      "Name of the access list\n"
+      "Add denied IMSI to the list\n"
+      "Regexp for IMSIs\n"
+      "CM Service Reject reason\n"
+      "LU Reject reason\n")
+{
+	struct bsc_msg_acc_lst *acc;
+	struct bsc_msg_acc_lst_entry *entry;
+
+	acc = bsc_msg_acc_lst_get(_ctx, _acc_lst, argv[0]);
+	if (!acc)
+		return CMD_WARNING;
+
+	entry = bsc_msg_acc_lst_entry_create(acc);
+	if (!entry)
+		return CMD_WARNING;
+
+	if (gsm_parse_reg(acc, &entry->imsi_deny_re, &entry->imsi_deny, argc - 1, &argv[1]) != 0)
+		return CMD_WARNING;
+	if (argc >= 3)
+		entry->cm_reject_cause = atoi(argv[2]);
+	if (argc >= 4)
+		entry->lu_reject_cause = atoi(argv[3]);
+	return CMD_SUCCESS;
+}
+
+void bsc_msg_acc_lst_write(struct vty *vty, struct bsc_msg_acc_lst *lst)
+{
+	struct bsc_msg_acc_lst_entry *entry;
+
+	llist_for_each_entry(entry, &lst->fltr_list, list) {
+		if (entry->imsi_allow)
+			vty_out(vty, " access-list %s imsi-allow %s%s",
+				lst->name, entry->imsi_allow, VTY_NEWLINE);
+		if (entry->imsi_deny)
+			vty_out(vty, " access-list %s imsi-deny %s %d %d%s",
+				lst->name, entry->imsi_deny,
+				entry->cm_reject_cause, entry->lu_reject_cause,
+				VTY_NEWLINE);
+	}
+}
+
+void bsc_msg_lst_vty_init(void *ctx, struct llist_head *lst, int node)
+{
+	_ctx = ctx;
+	_acc_lst = lst;
+	install_element_ve(&show_acc_lst_cmd);
+
+	/* access-list */
+	install_element(node, &cfg_lst_imsi_allow_cmd);
+	install_element(node, &cfg_lst_imsi_deny_cmd);
+	install_element(node, &cfg_lst_no_cmd);
+}
diff --git a/openbsc/src/osmo-bsc/Makefile.am b/openbsc/src/osmo-bsc/Makefile.am
index 6248fcd..b4a2cba 100644
--- a/openbsc/src/osmo-bsc/Makefile.am
+++ b/openbsc/src/osmo-bsc/Makefile.am
@@ -9,7 +9,9 @@
 		   osmo_bsc_grace.c osmo_bsc_msc.c osmo_bsc_sccp.c \
 		   osmo_bsc_filter.c osmo_bsc_bssap.c osmo_bsc_audio.c osmo_bsc_ctrl.c
 # once again since TRAU uses CC symbol :(
-osmo_bsc_LDADD = $(top_builddir)/src/libbsc/libbsc.a \
+osmo_bsc_LDADD = \
+		 $(top_builddir)/src/libfilter/libfilter.a \
+		 $(top_builddir)/src/libbsc/libbsc.a \
 		 $(top_builddir)/src/libmsc/libmsc.a \
 		 $(top_builddir)/src/libbsc/libbsc.a \
 		 $(top_builddir)/src/libtrau/libtrau.a \
diff --git a/openbsc/src/osmo-bsc/osmo_bsc_api.c b/openbsc/src/osmo-bsc/osmo_bsc_api.c
index 18b9607..5a01d6b 100644
--- a/openbsc/src/osmo-bsc/osmo_bsc_api.c
+++ b/openbsc/src/osmo-bsc/osmo_bsc_api.c
@@ -1,4 +1,4 @@
-/* (C) 2009-2011 by Holger Hans Peter Freyther <zecke@selfish.org>
+/* (C) 2009-2015 by Holger Hans Peter Freyther <zecke@selfish.org>
  * (C) 2009-2011 by On-Waves
  * All Rights Reserved
  *
@@ -79,6 +79,69 @@
 	return bts->cell_identity;
 }
 
+static void bsc_maybe_lu_reject(struct gsm_subscriber_connection *conn, int con_type, int cause)
+{
+	struct msgb *msg;
+
+	/* ignore cm service request or such */
+	if (con_type != FLT_CON_TYPE_LU)
+		return;
+
+	msg = gsm48_create_loc_upd_rej(cause);
+	if (!msg) {
+		LOGP(DMM, LOGL_ERROR, "Failed to create msg for LOCATION UPDATING REJECT.\n");
+		return;
+	}
+
+	msg->lchan = conn->lchan;
+	gsm0808_submit_dtap(conn, msg, 0, 0);
+}
+
+static int bsc_filter_initial(struct osmo_bsc_data *bsc,
+				struct osmo_msc_data *msc,
+				struct gsm_subscriber_connection *conn,
+				struct msgb *msg, char **imsi, int *con_type,
+				int *lu_cause)
+{
+	struct bsc_filter_request req;
+	struct bsc_filter_reject_cause cause;
+	struct gsm48_hdr *gh = msgb_l3(msg);
+	int rc;
+
+	req.ctx = conn;
+	req.black_list = NULL;
+	req.access_lists = bsc_access_lists();
+	req.local_lst_name = msc->acc_lst_name;
+	req.global_lst_name = conn->bts->network->bsc_data->acc_lst_name;
+	req.bsc_nr = 0;
+
+	rc = bsc_msg_filter_initial(gh, msgb_l3len(msg), &req,
+				con_type, imsi, &cause);
+	*lu_cause = cause.lu_reject_cause;
+	return rc;
+}
+
+static int bsc_filter_data(struct gsm_subscriber_connection *conn,
+				struct msgb *msg, int *lu_cause)
+{
+	struct bsc_filter_request req;
+	struct gsm48_hdr *gh = msgb_l3(msg);
+	struct bsc_filter_reject_cause cause;
+	int rc;
+
+	req.ctx = conn;
+	req.black_list = NULL;
+	req.access_lists = bsc_access_lists();
+	req.local_lst_name = conn->sccp_con->msc->acc_lst_name;
+	req.global_lst_name = conn->bts->network->bsc_data->acc_lst_name;
+	req.bsc_nr = 0;
+
+	rc = bsc_msg_filter_data(gh, msgb_l3len(msg), &req,
+				&conn->sccp_con->filter_state,
+				&cause);
+	*lu_cause = cause.lu_reject_cause;
+	return rc;
+}
 
 static void bsc_sapi_n_reject(struct gsm_subscriber_connection *conn, int dlci)
 {
@@ -172,6 +235,8 @@
 static int complete_layer3(struct gsm_subscriber_connection *conn,
 			   struct msgb *msg, struct osmo_msc_data *msc)
 {
+	int con_type, rc, lu_cause;
+	char *imsi = NULL;
 	struct timeval tv;
 	struct msgb *resp;
 	uint16_t network_code;
@@ -189,6 +254,14 @@
 	if (send_ping && osmo_timer_remaining(&msc->ping_timer, NULL, &tv) == -1)
 		send_ping = 0;
 
+	/* Check the filter */
+	rc = bsc_filter_initial(msc->network->bsc_data, msc, conn, msg,
+				&imsi, &con_type, &lu_cause);
+	if (rc < 0) {
+		bsc_maybe_lu_reject(conn, con_type, lu_cause);
+		return BSC_API_CONN_POL_REJECT;
+	}
+
 	/* allocate resource for a new connection */
 	ret = bsc_create_new_connection(conn, msc, send_ping);
 
@@ -202,6 +275,10 @@
 		return BSC_API_CONN_POL_REJECT;
 	}
 
+	if (imsi)
+		conn->sccp_con->filter_state.imsi = talloc_steal(conn, imsi);
+	conn->sccp_con->filter_state.con_type = con_type;
+
 	/* check return value, if failed check msg for and send USSD */
 
 	network_code = get_network_code_for_msc(conn->sccp_con->msc);
@@ -210,6 +287,7 @@
 	ci = get_ci_for_msc(conn->sccp_con->msc, conn->bts);
 
 	bsc_scan_bts_msg(conn, msg);
+
 	resp = gsm0808_create_layer3(msg, network_code, country_code, lac, ci);
 	if (!resp) {
 		LOGP(DMSC, LOGL_DEBUG, "Failed to create layer3 message.\n");
@@ -320,6 +398,7 @@
 
 static void bsc_dtap(struct gsm_subscriber_connection *conn, uint8_t link_id, struct msgb *msg)
 {
+	int lu_cause;
 	struct msgb *resp;
 	return_when_not_connected(conn);
 
@@ -332,8 +411,16 @@
 	if (handle_cc_setup(conn, msg) >= 1)
 		return;
 
-	bsc_scan_bts_msg(conn, msg);
+	/* Check the filter */
+	if (bsc_filter_data(conn, msg, &lu_cause) < 0) {
+		bsc_maybe_lu_reject(conn,
+					conn->sccp_con->filter_state.con_type,
+					lu_cause);
+		bsc_clear_request(conn, 0);
+		return;
+	}
 
+	bsc_scan_bts_msg(conn, msg);
 
 	resp = gsm0808_create_dtap(msg, link_id);
 	queue_msg_or_return(resp);
diff --git a/openbsc/src/osmo-bsc/osmo_bsc_main.c b/openbsc/src/osmo-bsc/osmo_bsc_main.c
index 5c38855..ee86cb6 100644
--- a/openbsc/src/osmo-bsc/osmo_bsc_main.c
+++ b/openbsc/src/osmo-bsc/osmo_bsc_main.c
@@ -59,6 +59,12 @@
 static const char *rf_ctrl = NULL;
 extern const char *openbsc_copyright;
 static int daemonize = 0;
+static struct llist_head access_lists;
+
+struct llist_head *bsc_access_lists(void)
+{
+	return &access_lists;
+}
 
 static void print_usage()
 {
@@ -196,6 +202,9 @@
 	vty_info.copyright = openbsc_copyright;
 	vty_init(&vty_info);
 	bsc_vty_init(&log_info);
+	bsc_msg_lst_vty_init(tall_bsc_ctx, &access_lists, BSC_NODE);
+
+	INIT_LLIST_HEAD(&access_lists);
 
 	/* parse options */
 	handle_options(argc, argv);
diff --git a/openbsc/src/osmo-bsc/osmo_bsc_vty.c b/openbsc/src/osmo-bsc/osmo_bsc_vty.c
index bbbba1c..06ad77d 100644
--- a/openbsc/src/osmo-bsc/osmo_bsc_vty.c
+++ b/openbsc/src/osmo-bsc/osmo_bsc_vty.c
@@ -1,5 +1,5 @@
 /* Osmo BSC VTY Configuration */
-/* (C) 2009-2014 by Holger Hans Peter Freyther
+/* (C) 2009-2015 by Holger Hans Peter Freyther
  * (C) 2009-2014 by On-Waves
  * All Rights Reserved
  *
@@ -24,6 +24,7 @@
 #include <openbsc/vty.h>
 #include <openbsc/gsm_subscriber.h>
 #include <openbsc/debug.h>
+#include <openbsc/bsc_msg_filter.h>
 
 #include <osmocom/core/talloc.h>
 #include <osmocom/vty/logging.h>
@@ -175,6 +176,9 @@
 	if (msc->local_pref)
 		vty_out(vty, " local-prefix %s%s", msc->local_pref, VTY_NEWLINE);
 
+	if (msc->acc_lst_name)
+		vty_out(vty, " access-list-name %s%s", msc->acc_lst_name, VTY_NEWLINE);
+
 	/* write amr options */
 	write_msc_amr_options(vty, msc);
 }
@@ -210,6 +214,8 @@
 		vty_out(vty, " missing-msc-text %s%s", bsc->ussd_no_msc_txt, VTY_NEWLINE);
 	else
 		vty_out(vty, " no missing-msc-text%s", VTY_NEWLINE);
+	if (bsc->acc_lst_name)
+		vty_out(vty, " access-list-name %s%s", bsc->acc_lst_name, VTY_NEWLINE);
 
 	return CMD_SUCCESS;
 }
@@ -625,6 +631,33 @@
 AMR_COMMAND(5_15)
 AMR_COMMAND(4_75)
 
+DEFUN(cfg_msc_acc_lst_name,
+      cfg_msc_acc_lst_name_cmd,
+      "access-list-name NAME",
+      "Set the name of the access list to use.\n"
+      "The name of the to be used access list.")
+{
+	struct osmo_msc_data *msc = osmo_msc_data(vty);
+
+	bsc_replace_string(msc, &msc->acc_lst_name, argv[0]);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_msc_no_acc_lst_name,
+      cfg_msc_no_acc_lst_name_cmd,
+      "no access-list-name",
+      NO_STR "Remove the access list from the NAT.\n")
+{
+	struct osmo_msc_data *msc = osmo_msc_data(vty);
+
+	if (msc->acc_lst_name) {
+		talloc_free(msc->acc_lst_name);
+		msc->acc_lst_name = NULL;
+	}
+
+	return CMD_SUCCESS;
+}
+
 DEFUN(cfg_net_bsc_mid_call_text,
       cfg_net_bsc_mid_call_text_cmd,
       "mid-call-text .TEXT",
@@ -681,6 +714,33 @@
 	return CMD_SUCCESS;
 }
 
+DEFUN(cfg_bsc_acc_lst_name,
+      cfg_bsc_acc_lst_name_cmd,
+      "access-list-name NAME",
+      "Set the name of the access list to use.\n"
+      "The name of the to be used access list.")
+{
+	struct osmo_bsc_data *bsc = osmo_bsc_data(vty);
+
+	bsc_replace_string(bsc, &bsc->acc_lst_name, argv[0]);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_bsc_no_acc_lst_name,
+      cfg_bsc_no_acc_lst_name_cmd,
+      "no access-list-name",
+      NO_STR "Remove the access list from the BSC\n")
+{
+	struct osmo_bsc_data *bsc = osmo_bsc_data(vty);
+
+	if (bsc->acc_lst_name) {
+		talloc_free(bsc->acc_lst_name);
+		bsc->acc_lst_name = NULL;
+	}
+
+	return CMD_SUCCESS;
+}
+
 DEFUN(show_statistics,
       show_statistics_cmd,
       "show statistics",
@@ -805,6 +865,8 @@
 	install_element(BSC_NODE, &cfg_net_no_rf_off_time_cmd);
 	install_element(BSC_NODE, &cfg_net_bsc_missing_msc_ussd_cmd);
 	install_element(BSC_NODE, &cfg_net_bsc_no_missing_msc_text_cmd);
+	install_element(BSC_NODE, &cfg_bsc_acc_lst_name_cmd);
+	install_element(BSC_NODE, &cfg_bsc_no_acc_lst_name_cmd);
 
 	install_node(&msc_node, config_write_msc);
 	vty_install_default(MSC_NODE);
@@ -839,6 +901,8 @@
 	install_element(MSC_NODE, &cfg_net_msc_amr_5_90_cmd);
 	install_element(MSC_NODE, &cfg_net_msc_amr_5_15_cmd);
 	install_element(MSC_NODE, &cfg_net_msc_amr_4_75_cmd);
+	install_element(MSC_NODE, &cfg_msc_acc_lst_name_cmd);
+	install_element(MSC_NODE, &cfg_msc_no_acc_lst_name_cmd);
 
 	install_element_ve(&show_statistics_cmd);
 	install_element_ve(&show_mscs_cmd);
diff --git a/openbsc/src/osmo-bsc_nat/Makefile.am b/openbsc/src/osmo-bsc_nat/Makefile.am
index ca103a4..d96a391 100644
--- a/openbsc/src/osmo-bsc_nat/Makefile.am
+++ b/openbsc/src/osmo-bsc_nat/Makefile.am
@@ -7,12 +7,13 @@
 
 osmo_bsc_nat_SOURCES = bsc_filter.c bsc_mgcp_utils.c bsc_nat.c bsc_nat_utils.c \
 		  bsc_nat_vty.c bsc_sccp.c bsc_ussd.c bsc_nat_ctrl.c \
-		  bsc_nat_rewrite.c bsc_nat_filter.c bsc_nat_rewrite_trie.c
+		  bsc_nat_rewrite.c bsc_nat_rewrite_trie.c bsc_nat_filter.c
 osmo_bsc_nat_LDADD = \
 		$(top_builddir)/src/libmgcp/libmgcp.a \
 		$(top_builddir)/src/libbsc/libbsc.a \
 		$(top_builddir)/src/libtrau/libtrau.a \
 		$(top_builddir)/src/libcommon/libcommon.a \
+		$(top_builddir)/src/libfilter/libfilter.a \
 		-lrt $(LIBOSMOSCCP_LIBS) $(LIBOSMOCORE_LIBS) \
 		$(LIBOSMOGSM_LIBS) $(LIBOSMOVTY_LIBS) $(LIBOSMOCTRL_LIBS) \
 		$(LIBOSMOABIS_LIBS) $(LIBOSMONETIF_LIBS)
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat.c b/openbsc/src/osmo-bsc_nat/bsc_nat.c
index 5c3b696..4357485 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat.c
@@ -39,6 +39,7 @@
 #include <openbsc/bsc_msc.h>
 #include <openbsc/bsc_nat.h>
 #include <openbsc/bsc_nat_sccp.h>
+#include <openbsc/bsc_msg_filter.h>
 #include <openbsc/ipaccess.h>
 #include <openbsc/abis_nm.h>
 #include <openbsc/socket.h>
@@ -425,7 +426,7 @@
  */
 static void bsc_send_con_release(struct bsc_connection *bsc,
 		struct nat_sccp_connection *con,
-		struct bsc_nat_reject_cause *cause)
+		struct bsc_filter_reject_cause *cause)
 {
 	struct msgb *rlsd;
 	/* 1. release the network */
@@ -441,7 +442,7 @@
 	con->msc_con = NULL;
 
 	/* 2. release the BSC side */
-	if (con->con_type == NAT_CON_TYPE_LU) {
+	if (con->filter_state.con_type == FLT_CON_TYPE_LU) {
 		struct msgb *payload, *udt;
 		payload = gsm48_create_loc_upd_rej(cause->lu_reject_cause);
 
@@ -469,20 +470,20 @@
 		return;
 	}
 
-	con->con_type = NAT_CON_TYPE_LOCAL_REJECT;
+	con->filter_state.con_type = FLT_CON_TYPE_LOCAL_REJECT;
 	bsc_write(bsc, rlsd, IPAC_PROTO_SCCP);
 }
 
 static void bsc_send_con_refuse(struct bsc_connection *bsc,
 			struct bsc_nat_parsed *parsed, int con_type,
-			struct bsc_nat_reject_cause *cause)
+			struct bsc_filter_reject_cause *cause)
 {
 	struct msgb *payload;
 	struct msgb *refuse;
 
-	if (con_type == NAT_CON_TYPE_LU)
+	if (con_type == FLT_CON_TYPE_LU)
 		payload = gsm48_create_loc_upd_rej(cause->lu_reject_cause);
-	else if (con_type == NAT_CON_TYPE_CM_SERV_REQ || con_type == NAT_CON_TYPE_SSA)
+	else if (con_type == FLT_CON_TYPE_CM_SERV_REQ || con_type == FLT_CON_TYPE_SSA)
 		payload = gsm48_create_mm_serv_rej(cause->cm_reject_cause);
 	else {
 		LOGP(DNAT, LOGL_ERROR, "Unknown connection type: %d\n", con_type);
@@ -503,7 +504,7 @@
 			goto send_refuse;
 
 		/* declare it local and assign a unique remote_ref */
-		con->con_type = NAT_CON_TYPE_LOCAL_REJECT;
+		con->filter_state.con_type = FLT_CON_TYPE_LOCAL_REJECT;
 		con->con_local = NAT_CON_END_LOCAL;
 		con->has_remote_ref = 1;
 		con->remote_ref = con->patched_ref;
@@ -1025,7 +1026,7 @@
 	struct bsc_connection *con_bsc = NULL;
 	int con_type;
 	struct bsc_nat_parsed *parsed;
-	struct bsc_nat_reject_cause cause;
+	struct bsc_filter_reject_cause cause;
 
 	/* Parse and filter messages */
 	parsed = bsc_nat_parse(msg);
@@ -1071,11 +1072,11 @@
 			con = patch_sccp_src_ref_to_msc(msg, parsed, bsc);
 			con->msc_con = bsc->nat->msc_con;
 			con_msc = con->msc_con;
-			con->con_type = con_type;
-			con->imsi_checked = filter;
+			con->filter_state.con_type = con_type;
+			con->filter_state.imsi_checked = filter;
 			bsc_nat_extract_lac(bsc, con, parsed, msg);
 			if (imsi)
-				con->imsi = talloc_steal(con, imsi);
+				con->filter_state.imsi = talloc_steal(con, imsi);
 			imsi = NULL;
 			con_bsc = con->bsc;
 			handle_con_stats(con);
@@ -1093,8 +1094,9 @@
 					filter = bsc_nat_filter_dt(bsc, msg,
 							con, parsed, &cause);
 					if (filter < 0) {
-						if (con->imsi)
-							bsc_nat_inform_reject(bsc, con->imsi);
+						if (con->filter_state.imsi)
+							bsc_nat_inform_reject(bsc,
+								con->filter_state.imsi);
 						bsc_stat_reject(filter, bsc, 1);
 						bsc_send_con_release(bsc, con, &cause);
 						con = NULL;
@@ -1110,7 +1112,8 @@
 					 * replace the msg and the parsed structure becomes
 					 * invalid.
 					 */
-					msg = bsc_nat_rewrite_msg(bsc->nat, msg, parsed, con->imsi);
+					msg = bsc_nat_rewrite_msg(bsc->nat, msg, parsed,
+									con->filter_state.imsi);
 					talloc_free(parsed);
 					parsed = NULL;
 				} else if (con->con_local == NAT_CON_END_USSD) {
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_ctrl.c b/openbsc/src/osmo-bsc_nat/bsc_nat_ctrl.c
index 4b59b40..f3ca924 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_ctrl.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_ctrl.c
@@ -29,6 +29,7 @@
 
 #include <openbsc/ctrl.h>
 #include <openbsc/bsc_nat.h>
+#include <openbsc/bsc_msg_filter.h>
 #include <openbsc/vty.h>
 #include <openbsc/gsm_data.h>
 
@@ -404,19 +405,19 @@
 static int set_net_cfg_acc_cmd(struct ctrl_cmd *cmd, void *data)
 {
 	const char *access_name = extract_acc_name(cmd->variable);
-	struct bsc_nat_acc_lst *acc;
-	struct bsc_nat_acc_lst_entry *entry;
+	struct bsc_msg_acc_lst *acc;
+	struct bsc_msg_acc_lst_entry *entry;
 	const char *value = cmd->value;
 	int rc;
 
 	/* Should have been caught by verify_net_cfg_acc_cmd */
-	acc = bsc_nat_acc_lst_find(g_nat, access_name);
+	acc = bsc_msg_acc_lst_find(&g_nat->access_lists, access_name);
 	if (!acc) {
 		cmd->reply = "Access list not found";
 		return CTRL_CMD_ERROR;
 	}
 
-	entry = bsc_nat_acc_lst_entry_create(acc);
+	entry = bsc_msg_acc_lst_entry_create(acc);
 	if (!entry) {
 		cmd->reply = "OOM";
 		return CTRL_CMD_ERROR;
@@ -435,7 +436,7 @@
 static int verify_net_cfg_acc_cmd(struct ctrl_cmd *cmd, const char *value, void *data)
 {
 	const char *access_name = extract_acc_name(cmd->variable);
-	struct bsc_nat_acc_lst *acc = bsc_nat_acc_lst_find(g_nat, access_name);
+	struct bsc_msg_acc_lst *acc = bsc_msg_acc_lst_find(&g_nat->access_lists, access_name);
 
 	if (!acc) {
 		cmd->reply = "Access list not known";
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c b/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c
index 64f6d73..393aea3 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c
@@ -1,8 +1,5 @@
 /*
- * Access filtering
- */
-/*
- * (C) 2010-2012 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2010-2015 by Holger Hans Peter Freyther <zecke@selfish.org>
  * (C) 2010-2012 by On-Waves
  * All Rights Reserved
  *
@@ -23,13 +20,9 @@
 
 #include <openbsc/bsc_nat.h>
 #include <openbsc/bsc_nat_sccp.h>
-#include <openbsc/bsc_msc.h>
-#include <openbsc/gsm_data.h>
+#include <openbsc/bsc_msg_filter.h>
 #include <openbsc/debug.h>
-#include <openbsc/ipaccess.h>
 
-#include <osmocom/core/linuxlist.h>
-#include <osmocom/core/talloc.h>
 #include <osmocom/gsm/gsm0808.h>
 
 #include <osmocom/gsm/protocol/gsm_08_08.h>
@@ -37,307 +30,18 @@
 
 #include <osmocom/sccp/sccp.h>
 
-int bsc_nat_barr_find(struct rb_root *root, const char *imsi, int *cm, int *lu)
-{
-	struct bsc_nat_barr_entry *n;
-	n = rb_entry(root->rb_node, struct bsc_nat_barr_entry, node);
-
-	while (n) {
-		int rc = strcmp(imsi, n->imsi);
-		if (rc == 0) {
-			*cm = n->cm_reject_cause;
-			*lu = n->lu_reject_cause;
-			return 1;
-		}
-
-		n = rb_entry(
-			(rc < 0) ? n->node.rb_left : n->node.rb_right,
-			struct bsc_nat_barr_entry, node);
-	};
-
-	return 0;
-}
-
-static int insert_barr_node(struct bsc_nat_barr_entry *entry, struct rb_root *root)
-{
-	struct rb_node **new = &root->rb_node, *parent = NULL;
-
-	while (*new) {
-		int rc;
-		struct bsc_nat_barr_entry *this;
-		this = rb_entry(*new, struct bsc_nat_barr_entry, node);
-		parent = *new;
-
-		rc = strcmp(entry->imsi, this->imsi);
-		if (rc < 0)
-			new = &((*new)->rb_left);
-		else if (rc > 0)
-			new = &((*new)->rb_right);
-		else {
-			LOGP(DNAT, LOGL_ERROR,
-				"Duplicate entry for IMSI(%s)\n", entry->imsi);
-			talloc_free(entry);
-			return -1;
-		}
-	}
-
-	rb_link_node(&entry->node, parent, new);
-	rb_insert_color(&entry->node, root);
-	return 0;
-}
-
-int bsc_nat_barr_adapt(void *ctx, struct rb_root *root,
-			const struct osmo_config_list *list)
-{
-	struct osmo_config_entry *cfg_entry;
-	int err = 0;
-
-	/* free the old data */
-	while (!RB_EMPTY_ROOT(root)) {
-		struct rb_node *node = rb_first(root);
-		rb_erase(node, root);
-		talloc_free(node);
-	}
-
-	if (!list)
-		return 0;
-
-	/* now adapt the new list */
-	llist_for_each_entry(cfg_entry, &list->entry, list) {
-		struct bsc_nat_barr_entry *entry;
-		entry = talloc_zero(ctx, struct bsc_nat_barr_entry);
-		if (!entry) {
-			LOGP(DNAT, LOGL_ERROR,
-				"Allocation of the barr entry failed.\n");
-			continue;
-		}
-
-		entry->imsi = talloc_strdup(entry, cfg_entry->mcc);
-		entry->cm_reject_cause = atoi(cfg_entry->mnc);
-		entry->lu_reject_cause = atoi(cfg_entry->option);
-		err |= insert_barr_node(entry, root);
-	}
-
-	return err;
-}
-
-
-static int lst_check_deny(struct bsc_nat_acc_lst *lst, const char *mi_string,
-			int *cm_cause, int *lu_cause)
-{
-	struct bsc_nat_acc_lst_entry *entry;
-
-	llist_for_each_entry(entry, &lst->fltr_list, list) {
-		if (!entry->imsi_deny)
-			continue;
-		if (regexec(&entry->imsi_deny_re, mi_string, 0, NULL, 0) == 0) {
-			*cm_cause = entry->cm_reject_cause;
-			*lu_cause = entry->lu_reject_cause;
-			return 0;
-		}
-	}
-
-	return 1;
-}
-
-/* apply white/black list */
-static int auth_imsi(struct bsc_connection *bsc, const char *imsi,
-		struct bsc_nat_reject_cause *cause)
-{
-	/*
-	 * Now apply blacklist/whitelist of the BSC and the NAT.
-	 * 1.) Check the global IMSI barr list
-	 * 2.) Allow directly if the IMSI is allowed at the BSC
-	 * 3.) Reject if the IMSI is not allowed at the BSC
-	 * 4.) Reject if the IMSI not allowed at the global level.
-	 * 5.) Allow directly if the IMSI is allowed at the global level
-	 */
-	int cm, lu;
-	struct bsc_nat_acc_lst *nat_lst = NULL;
-	struct bsc_nat_acc_lst *bsc_lst = NULL;
-
-	/* 1. global check for barred imsis */
-	if (bsc_nat_barr_find(&bsc->nat->imsi_black_list, imsi, &cm, &lu)) {
-		cause->cm_reject_cause = cm;
-		cause->lu_reject_cause = lu;
-		LOGP(DNAT, LOGL_DEBUG,
-			"Blocking subscriber IMSI %s with CM: %d LU: %d\n",
-			imsi, cm, lu);
-		return -4;
-	}
-
-
-	bsc_lst = bsc_nat_acc_lst_find(bsc->nat, bsc->cfg->acc_lst_name);
-	nat_lst = bsc_nat_acc_lst_find(bsc->nat, bsc->nat->acc_lst_name);
-
-
-	if (bsc_lst) {
-		/* 2. BSC allow */
-		if (bsc_nat_lst_check_allow(bsc_lst, imsi) == 0)
-			return 1;
-
-		/* 3. BSC deny */
-		if (lst_check_deny(bsc_lst, imsi, &cm, &lu) == 0) {
-			LOGP(DNAT, LOGL_ERROR,
-			     "Filtering %s by imsi_deny on bsc nr: %d.\n", imsi, bsc->cfg->nr);
-			rate_ctr_inc(&bsc_lst->stats->ctr[ACC_LIST_BSC_FILTER]);
-			cause->cm_reject_cause = cm;
-			cause->lu_reject_cause = lu;
-			return -2;
-		}
-
-	}
-
-	/* 4. NAT deny */
-	if (nat_lst) {
-		if (lst_check_deny(nat_lst, imsi, &cm, &lu) == 0) {
-			LOGP(DNAT, LOGL_ERROR,
-			     "Filtering %s by nat imsi_deny on bsc nr: %d.\n", imsi, bsc->cfg->nr);
-			rate_ctr_inc(&nat_lst->stats->ctr[ACC_LIST_NAT_FILTER]);
-			cause->cm_reject_cause = cm;
-			cause->lu_reject_cause = lu;
-			return -3;
-		}
-	}
-
-	return 1;
-}
-
-static int _cr_check_loc_upd(struct bsc_connection *bsc,
-			     uint8_t *data, unsigned int length,
-			     char **imsi)
-{
-	uint8_t mi_type;
-	struct gsm48_loc_upd_req *lu;
-	char mi_string[GSM48_MI_SIZE];
-
-	if (length < sizeof(*lu)) {
-		LOGP(DNAT, LOGL_ERROR,
-		     "LU does not fit. Length is %d \n", length);
-		return -1;
-	}
-
-	lu = (struct gsm48_loc_upd_req *) data;
-	mi_type = lu->mi[0] & GSM_MI_TYPE_MASK;
-
-	/*
-	 * We can only deal with the IMSI. This will fail for a phone that
-	 * will send the TMSI of a previous network to us.
-	 */
-	if (mi_type != GSM_MI_TYPE_IMSI)
-		return 0;
-
-	gsm48_mi_to_string(mi_string, sizeof(mi_string), lu->mi, lu->mi_len);
-	*imsi = talloc_strdup(bsc, mi_string);
-	return 1;
-}
-
-static int _cr_check_cm_serv_req(struct bsc_connection *bsc,
-				 uint8_t *data, unsigned int length,
-				 int *con_type, char **imsi)
-{
-	static const uint32_t classmark_offset =
-				offsetof(struct gsm48_service_request, classmark);
-
-	char mi_string[GSM48_MI_SIZE];
-	uint8_t mi_type;
-	int rc;
-	struct gsm48_service_request *req;
-
-	/* unfortunately in Phase1 the classmark2 length is variable */
-
-	if (length < sizeof(*req)) {
-		LOGP(DNAT, LOGL_ERROR,
-		     "CM Serv Req does not fit. Length is %d\n", length);
-		return -1;
-	}
-
-	req = (struct gsm48_service_request *) data;
-	if (req->cm_service_type == 0x8)
-		*con_type = NAT_CON_TYPE_SSA;
-	rc = gsm48_extract_mi((uint8_t *) &req->classmark,
-			      length - classmark_offset, mi_string, &mi_type);
-	if (rc < 0) {
-		LOGP(DNAT, LOGL_ERROR, "Failed to parse the classmark2/mi. error: %d\n", rc);
-		return -1;
-	}
-
-	/* we have to let the TMSI or such pass */
-	if (mi_type != GSM_MI_TYPE_IMSI)
-		return 0;
-
-	*imsi = talloc_strdup(bsc, mi_string);
-	return 1;
-}
-
-static int _cr_check_pag_resp(struct bsc_connection *bsc,
-			      uint8_t *data, unsigned int length, char **imsi)
-{
-	struct gsm48_pag_resp *resp;
-	char mi_string[GSM48_MI_SIZE];
-	uint8_t mi_type;
-
-	if (length < sizeof(*resp)) {
-		LOGP(DNAT, LOGL_ERROR, "PAG RESP does not fit. Length was %d.\n", length);
-		return -1;
-	}
-
-	resp = (struct gsm48_pag_resp *) data;
-	if (gsm48_paging_extract_mi(resp, length, mi_string, &mi_type) < 0) {
-		LOGP(DNAT, LOGL_ERROR, "Failed to extract the MI.\n");
-		return -1;
-	}
-
-	/* we need to let it pass for now */
-	if (mi_type != GSM_MI_TYPE_IMSI)
-		return 0;
-
-	*imsi = talloc_strdup(bsc, mi_string);
-	return 1;
-}
-
-static int _dt_check_id_resp(struct bsc_connection *bsc,
-			     uint8_t *data, unsigned int length,
-			     struct nat_sccp_connection *con,
-			     struct bsc_nat_reject_cause *cause)
-{
-	char mi_string[GSM48_MI_SIZE];
-	uint8_t mi_type;
-
-	if (length < 2) {
-		LOGP(DNAT, LOGL_ERROR, "mi does not fit.\n");
-		return -1;
-	}
-
-	if (data[0] < length - 1) {
-		LOGP(DNAT, LOGL_ERROR, "mi length too big.\n");
-		return -2;
-	}
-
-	mi_type = data[1] & GSM_MI_TYPE_MASK;
-	gsm48_mi_to_string(mi_string, sizeof(mi_string), &data[1], data[0]);
-
-	if (mi_type != GSM_MI_TYPE_IMSI)
-		return 0;
-
-	con->imsi_checked = 1;
-	con->imsi = talloc_strdup(con, mi_string);
-	return auth_imsi(bsc, mi_string, cause);
-}
-
-
 /* Filter out CR data... */
 int bsc_nat_filter_sccp_cr(struct bsc_connection *bsc, struct msgb *msg,
 			struct bsc_nat_parsed *parsed, int *con_type,
-			char **imsi, struct bsc_nat_reject_cause *cause)
+			char **imsi, struct bsc_filter_reject_cause *cause)
 {
+	struct bsc_filter_request req;
 	struct tlv_parsed tp;
 	struct gsm48_hdr *hdr48;
 	int hdr48_len;
-	int len, ret = 0;
-	uint8_t msg_type, proto;
+	int len;
 
-	*con_type = NAT_CON_TYPE_NONE;
+	*con_type = FLT_CON_TYPE_NONE;
 	cause->cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
 	cause->lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
 	*imsi = NULL;
@@ -374,55 +78,27 @@
 	}
 
 	hdr48 = (struct gsm48_hdr *) TLVP_VAL(&tp, GSM0808_IE_LAYER_3_INFORMATION);
-
-	proto = hdr48->proto_discr & 0x0f;
-	msg_type = hdr48->msg_type & 0xbf;
-	if (proto == GSM48_PDISC_MM &&
-	    msg_type == GSM48_MT_MM_LOC_UPD_REQUEST) {
-		*con_type = NAT_CON_TYPE_LU;
-		ret = _cr_check_loc_upd(bsc, &hdr48->data[0],
-					hdr48_len - sizeof(*hdr48), imsi);
-	} else if (proto == GSM48_PDISC_MM &&
-		  msg_type == GSM48_MT_MM_CM_SERV_REQ) {
-		*con_type = NAT_CON_TYPE_CM_SERV_REQ;
-		ret = _cr_check_cm_serv_req(bsc, &hdr48->data[0],
-					     hdr48_len - sizeof(*hdr48),
-					     con_type, imsi);
-	} else if (proto == GSM48_PDISC_RR &&
-		   msg_type == GSM48_MT_RR_PAG_RESP) {
-		*con_type = NAT_CON_TYPE_PAG_RESP;
-		ret = _cr_check_pag_resp(bsc, &hdr48->data[0],
-					hdr48_len - sizeof(*hdr48), imsi);
-	} else {
-		/* We only want to filter the above, let other things pass */
-		*con_type = NAT_CON_TYPE_OTHER;
-		return 0;
-	}
-
-	/* check if we are done */
-	if (ret != 1)
-		return ret;
-
-	/* the memory allocation failed */
-	if (!*imsi)
-		return -1;
-
-	/* now check the imsi */
-	return auth_imsi(bsc, *imsi, cause);
+	req.ctx = bsc;
+	req.black_list = &bsc->nat->imsi_black_list;
+	req.access_lists = &bsc->nat->access_lists;
+	req.local_lst_name = bsc->cfg->acc_lst_name;
+	req.global_lst_name = bsc->nat->acc_lst_name;
+	req.bsc_nr = bsc->cfg->nr;
+	return bsc_msg_filter_initial(hdr48, hdr48_len, &req, con_type, imsi, cause);
 }
 
 int bsc_nat_filter_dt(struct bsc_connection *bsc, struct msgb *msg,
 		struct nat_sccp_connection *con, struct bsc_nat_parsed *parsed,
-		struct bsc_nat_reject_cause *cause)
+		struct bsc_filter_reject_cause *cause)
 {
 	uint32_t len;
-	uint8_t msg_type, proto;
 	struct gsm48_hdr *hdr48;
+	struct bsc_filter_request req;
 
 	cause->cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
 	cause->lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
 
-	if (con->imsi_checked)
+	if (con->filter_state.imsi_checked)
 		return 0;
 
 	/* only care about DTAP messages */
@@ -433,11 +109,11 @@
 	if (!hdr48)
 		return -1;
 
-	proto = hdr48->proto_discr & 0x0f;
-	msg_type = hdr48->msg_type & 0xbf;
-	if (proto != GSM48_PDISC_MM || msg_type != GSM48_MT_MM_ID_RESP)
-		return 0;
-
-	return _dt_check_id_resp(bsc, &hdr48->data[0],
-					len - sizeof(*hdr48), con, cause);
+	req.ctx = bsc;
+	req.black_list = &bsc->nat->imsi_black_list;
+	req.access_lists = &bsc->nat->access_lists;
+	req.local_lst_name = bsc->cfg->acc_lst_name;
+	req.global_lst_name = bsc->nat->acc_lst_name;
+	req.bsc_nr = bsc->cfg->nr;
+	return bsc_msg_filter_data(hdr48, len, &req, &con->filter_state, cause);
 }
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
index 70ad577..d95227d 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
@@ -23,6 +23,7 @@
 
 #include <openbsc/bsc_nat.h>
 #include <openbsc/bsc_nat_sccp.h>
+#include <openbsc/bsc_msg_filter.h>
 #include <openbsc/bsc_msc.h>
 #include <openbsc/gsm_data.h>
 #include <openbsc/debug.h>
@@ -66,18 +67,6 @@
 	.ctr_desc = bsc_cfg_ctr_description,
 };
 
-static const struct rate_ctr_desc acc_list_ctr_description[] = {
-	[ACC_LIST_BSC_FILTER]	= { "access-list.bsc-filter", "Rejected by rule for BSC"},
-	[ACC_LIST_NAT_FILTER]	= { "access-list.nat-filter", "Rejected by rule for NAT"},
-};
-
-static const struct rate_ctr_group_desc bsc_cfg_acc_list_desc = {
-	.group_name_prefix = "nat.filter",
-	.group_description = "NAT Access-List Statistics",
-	.num_ctr = ARRAY_SIZE(acc_list_ctr_description),
-	.ctr_desc = acc_list_ctr_description,
-};
-
 struct bsc_nat *bsc_nat_alloc(void)
 {
 	struct bsc_nat *nat = talloc_zero(tall_bsc_ctx, struct bsc_nat);
@@ -123,12 +112,12 @@
 void bsc_nat_free(struct bsc_nat *nat)
 {
 	struct bsc_config *cfg, *tmp;
-	struct bsc_nat_acc_lst *lst, *tmp_lst;
+	struct bsc_msg_acc_lst *lst, *tmp_lst;
 
 	llist_for_each_entry_safe(cfg, tmp, &nat->bsc_configs, entry)
 		bsc_config_free(cfg);
 	llist_for_each_entry_safe(lst, tmp_lst, &nat->access_lists, list)
-		bsc_nat_acc_lst_delete(lst);
+		bsc_msg_acc_lst_delete(lst);
 
 	bsc_nat_num_rewr_entry_adapt(nat, &nat->num_rewr, NULL);
 	bsc_nat_num_rewr_entry_adapt(nat, &nat->num_rewr_post, NULL);
@@ -392,20 +381,6 @@
 	return 0;
 }
 
-int bsc_nat_lst_check_allow(struct bsc_nat_acc_lst *lst, const char *mi_string)
-{
-	struct bsc_nat_acc_lst_entry *entry;
-
-	llist_for_each_entry(entry, &lst->fltr_list, list) {
-		if (!entry->imsi_allow)
-			continue;
-		if (regexec(&entry->imsi_allow_re, mi_string, 0, NULL, 0) == 0)
-			return 0;
-	}
-
-	return 1;
-}
-
 struct gsm48_hdr *bsc_unpack_dtap(struct bsc_nat_parsed *parsed,
 				  struct msgb *msg, uint32_t *len)
 {
@@ -428,13 +403,13 @@
 }
 
 static const char *con_types [] = {
-	[NAT_CON_TYPE_NONE] = "n/a",
-	[NAT_CON_TYPE_LU] = "Location Update",
-	[NAT_CON_TYPE_CM_SERV_REQ] = "CM Serv Req",
-	[NAT_CON_TYPE_PAG_RESP] = "Paging Response",
-	[NAT_CON_TYPE_SSA] = "Supplementar Service Activation",
-	[NAT_CON_TYPE_LOCAL_REJECT] = "Local Reject",
-	[NAT_CON_TYPE_OTHER] = "Other",
+	[FLT_CON_TYPE_NONE] = "n/a",
+	[FLT_CON_TYPE_LU] = "Location Update",
+	[FLT_CON_TYPE_CM_SERV_REQ] = "CM Serv Req",
+	[FLT_CON_TYPE_PAG_RESP] = "Paging Response",
+	[FLT_CON_TYPE_SSA] = "Supplementar Service Activation",
+	[FLT_CON_TYPE_LOCAL_REJECT] = "Local Reject",
+	[FLT_CON_TYPE_OTHER] = "Other",
 };
 
 const char *bsc_con_type_to_string(int type)
@@ -442,86 +417,24 @@
 	return con_types[type];
 }
 
-struct bsc_nat_acc_lst *bsc_nat_acc_lst_find(struct bsc_nat *nat, const char *name)
-{
-	struct bsc_nat_acc_lst *lst;
-
-	if (!name)
-		return NULL;
-
-	llist_for_each_entry(lst, &nat->access_lists, list)
-		if (strcmp(lst->name, name) == 0)
-			return lst;
-
-	return NULL;
-}
-
-struct bsc_nat_acc_lst *bsc_nat_acc_lst_get(struct bsc_nat *nat, const char *name)
-{
-	struct bsc_nat_acc_lst *lst;
-
-	lst = bsc_nat_acc_lst_find(nat, name);
-	if (lst)
-		return lst;
-
-	lst = talloc_zero(nat, struct bsc_nat_acc_lst);
-	if (!lst) {
-		LOGP(DNAT, LOGL_ERROR, "Failed to allocate access list");
-		return NULL;
-	}
-
-	/* TODO: get the index right */
-	lst->stats = rate_ctr_group_alloc(lst, &bsc_cfg_acc_list_desc, 0);
-	if (!lst->stats) {
-		talloc_free(lst);
-		return NULL;
-	}
-
-	INIT_LLIST_HEAD(&lst->fltr_list);
-	lst->name = talloc_strdup(lst, name);
-	llist_add_tail(&lst->list, &nat->access_lists);
-	return lst;
-}
-
-void bsc_nat_acc_lst_delete(struct bsc_nat_acc_lst *lst)
-{
-	llist_del(&lst->list);
-	rate_ctr_group_free(lst->stats);
-	talloc_free(lst);
-}
-
-struct bsc_nat_acc_lst_entry *bsc_nat_acc_lst_entry_create(struct bsc_nat_acc_lst *lst)
-{
-	struct bsc_nat_acc_lst_entry *entry;
-
-	entry = talloc_zero(lst, struct bsc_nat_acc_lst_entry);
-	if (!entry)
-		return NULL;
-
-	entry->cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
-	entry->lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
-	llist_add_tail(&entry->list, &lst->fltr_list);
-	return entry;
-}
-
 int bsc_nat_msc_is_connected(struct bsc_nat *nat)
 {
 	return nat->msc_con->is_connected;
 }
 
 static const int con_to_ctr[] = {
-	[NAT_CON_TYPE_NONE]		= -1,
-	[NAT_CON_TYPE_LU]		= BCFG_CTR_CON_TYPE_LU,
-	[NAT_CON_TYPE_CM_SERV_REQ]	= BCFG_CTR_CON_CMSERV_RQ,
-	[NAT_CON_TYPE_PAG_RESP]		= BCFG_CTR_CON_PAG_RESP,
-	[NAT_CON_TYPE_SSA]		= BCFG_CTR_CON_SSA,
-	[NAT_CON_TYPE_LOCAL_REJECT]	= -1,
-	[NAT_CON_TYPE_OTHER]		= BCFG_CTR_CON_OTHER,
+	[FLT_CON_TYPE_NONE]		= -1,
+	[FLT_CON_TYPE_LU]		= BCFG_CTR_CON_TYPE_LU,
+	[FLT_CON_TYPE_CM_SERV_REQ]	= BCFG_CTR_CON_CMSERV_RQ,
+	[FLT_CON_TYPE_PAG_RESP]		= BCFG_CTR_CON_PAG_RESP,
+	[FLT_CON_TYPE_SSA]		= BCFG_CTR_CON_SSA,
+	[FLT_CON_TYPE_LOCAL_REJECT]	= -1,
+	[FLT_CON_TYPE_OTHER]		= BCFG_CTR_CON_OTHER,
 };
 
 int bsc_conn_type_to_ctr(struct nat_sccp_connection *conn)
 {
-	return con_to_ctr[conn->con_type];
+	return con_to_ctr[conn->filter_state.con_type];
 }
 
 int bsc_write_cb(struct osmo_fd *bfd, struct msgb *msg)
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c b/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c
index 9e66cdc..821e522 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c
@@ -22,6 +22,7 @@
 #include <openbsc/gsm_data.h>
 #include <openbsc/bsc_nat.h>
 #include <openbsc/bsc_nat_sccp.h>
+#include <openbsc/bsc_msg_filter.h>
 #include <openbsc/bsc_msc.h>
 #include <openbsc/gsm_04_08.h>
 #include <openbsc/mgcp.h>
@@ -70,22 +71,6 @@
 	return CMD_SUCCESS;
 }
 
-static void write_acc_lst(struct vty *vty, struct bsc_nat_acc_lst *lst)
-{
-	struct bsc_nat_acc_lst_entry *entry;
-
-	llist_for_each_entry(entry, &lst->fltr_list, list) {
-		if (entry->imsi_allow)
-			vty_out(vty, " access-list %s imsi-allow %s%s",
-				lst->name, entry->imsi_allow, VTY_NEWLINE);
-		if (entry->imsi_deny)
-			vty_out(vty, " access-list %s imsi-deny %s %d %d%s",
-				lst->name, entry->imsi_deny,
-				entry->cm_reject_cause, entry->lu_reject_cause,
-				VTY_NEWLINE);
-	}
-}
-
 static void dump_lac(struct vty *vty, struct llist_head *head)
 {
 	struct bsc_lac_entry *lac;
@@ -102,7 +87,7 @@
 
 static int config_write_nat(struct vty *vty)
 {
-	struct bsc_nat_acc_lst *lst;
+	struct bsc_msg_acc_lst *lst;
 	struct bsc_nat_paging_group *pgroup;
 
 	vty_out(vty, "nat%s", VTY_NEWLINE);
@@ -151,7 +136,7 @@
 			_nat->num_rewr_trie_name, VTY_NEWLINE);
 
 	llist_for_each_entry(lst, &_nat->access_lists, list)
-		write_acc_lst(vty, lst);
+		bsc_msg_acc_lst_write(vty, lst);
 	llist_for_each_entry(pgroup, &_nat->paging_groups, entry)
 		write_pgroup_lst(vty, pgroup);
 	if (_nat->mgcp_ipa)
@@ -204,7 +189,7 @@
 			con->has_remote_ref,
 			sccp_src_ref_to_int(&con->remote_ref),
 			con->msc_endp, con->bsc_endp,
-			bsc_con_type_to_string(con->con_type),
+			bsc_con_type_to_string(con->filter_state.con_type),
 			VTY_NEWLINE);
 	}
 
@@ -518,7 +503,7 @@
 		int rc;
 		struct osmo_config_list *rewr = NULL;
 		rewr = osmo_config_list_parse(_nat, _nat->imsi_black_list_fn);
-		rc = bsc_nat_barr_adapt(_nat, &_nat->imsi_black_list, rewr);
+		rc = bsc_filter_barr_adapt(_nat, &_nat->imsi_black_list, rewr);
 		if (rc != 0) {
 			vty_out(vty, "%%There was an error parsing the list."
 				" Please see the error log.%s", VTY_NEWLINE);
@@ -528,7 +513,7 @@
 		return CMD_SUCCESS;
 	}
 
-	bsc_nat_barr_adapt(_nat, &_nat->imsi_black_list, NULL);
+	bsc_filter_barr_adapt(_nat, &_nat->imsi_black_list, NULL);
 	return CMD_SUCCESS;
 }
 
@@ -539,7 +524,7 @@
 {
 	talloc_free(_nat->imsi_black_list_fn);
 	_nat->imsi_black_list_fn = NULL;
-	bsc_nat_barr_adapt(_nat, &_nat->imsi_black_list, NULL);
+	bsc_filter_barr_adapt(_nat, &_nat->imsi_black_list, NULL);
 	return CMD_SUCCESS;
 }
 
@@ -867,94 +852,6 @@
 	return CMD_SUCCESS;
 }
 
-
-
-DEFUN(cfg_lst_imsi_allow,
-      cfg_lst_imsi_allow_cmd,
-      "access-list NAME imsi-allow [REGEXP]",
-      "Access list commands\n"
-      "Name of the access list\n"
-      "Add allowed IMSI to the list\n"
-      "Regexp for IMSIs\n")
-{
-	struct bsc_nat_acc_lst *acc;
-	struct bsc_nat_acc_lst_entry *entry;
-
-	acc = bsc_nat_acc_lst_get(_nat, argv[0]);
-	if (!acc)
-		return CMD_WARNING;
-
-	entry = bsc_nat_acc_lst_entry_create(acc);
-	if (!entry)
-		return CMD_WARNING;
-
-	if (gsm_parse_reg(acc, &entry->imsi_allow_re, &entry->imsi_allow, argc - 1, &argv[1]) != 0)
-		return CMD_WARNING;
-	return CMD_SUCCESS;
-}
-
-DEFUN(cfg_lst_imsi_deny,
-      cfg_lst_imsi_deny_cmd,
-      "access-list NAME imsi-deny [REGEXP] (<0-256>) (<0-256>)",
-      "Access list commands\n"
-      "Name of the access list\n"
-      "Add denied IMSI to the list\n"
-      "Regexp for IMSIs\n"
-      "CM Service Reject reason\n"
-      "LU Reject reason\n")
-{
-	struct bsc_nat_acc_lst *acc;
-	struct bsc_nat_acc_lst_entry *entry;
-
-	acc = bsc_nat_acc_lst_get(_nat, argv[0]);
-	if (!acc)
-		return CMD_WARNING;
-
-	entry = bsc_nat_acc_lst_entry_create(acc);
-	if (!entry)
-		return CMD_WARNING;
-
-	if (gsm_parse_reg(acc, &entry->imsi_deny_re, &entry->imsi_deny, argc - 1, &argv[1]) != 0)
-		return CMD_WARNING;
-	if (argc >= 3)
-		entry->cm_reject_cause = atoi(argv[2]);
-	if (argc >= 4)
-		entry->lu_reject_cause = atoi(argv[3]);
-	return CMD_SUCCESS;
-}
-
-/* naming to follow Zebra... */
-DEFUN(cfg_lst_no,
-      cfg_lst_no_cmd,
-      "no access-list NAME",
-      NO_STR "Remove an access-list by name\n"
-      "The access-list to remove\n")
-{
-	struct bsc_nat_acc_lst *acc;
-	acc = bsc_nat_acc_lst_find(_nat, argv[0]);
-	if (!acc)
-		return CMD_WARNING;
-
-	bsc_nat_acc_lst_delete(acc);
-	return CMD_SUCCESS;
-}
-
-DEFUN(show_acc_lst,
-      show_acc_lst_cmd,
-      "show access-list NAME",
-      SHOW_STR "IMSI access list\n" "Name of the access list\n")
-{
-	struct bsc_nat_acc_lst *acc;
-	acc = bsc_nat_acc_lst_find(_nat, argv[0]);
-	if (!acc)
-		return CMD_WARNING;
-
-	vty_out(vty, "access-list %s%s", acc->name, VTY_NEWLINE);
-	vty_out_rate_ctr_group(vty, " ", acc->stats);
-
-	return CMD_SUCCESS;
-}
-
 DEFUN(show_bar_lst,
       show_bar_lst_cmd,
       "show imsi-black-list",
@@ -965,8 +862,8 @@
 	vty_out(vty, "IMSIs barred from the network:%s", VTY_NEWLINE);
 
 	for (node = rb_first(&_nat->imsi_black_list); node; node = rb_next(node)) {
-		struct bsc_nat_barr_entry *entry;
-		entry = rb_entry(node, struct bsc_nat_barr_entry, node);
+		struct bsc_filter_barr_entry *entry;
+		entry = rb_entry(node, struct bsc_filter_barr_entry, node);
 
 		vty_out(vty, " IMSI(%s) CM-Reject-Cause(%d) LU-Reject-Cause(%d)%s",
 			entry->imsi, entry->cm_reject_cause, entry->lu_reject_cause,
@@ -1245,7 +1142,6 @@
 	install_element_ve(&show_msc_cmd);
 	install_element_ve(&test_regex_cmd);
 	install_element_ve(&show_bsc_mgcp_cmd);
-	install_element_ve(&show_acc_lst_cmd);
 	install_element_ve(&show_bar_lst_cmd);
 	install_element_ve(&show_prefix_tree_cmd);
 	install_element_ve(&show_ussd_connection_cmd);
@@ -1275,10 +1171,7 @@
 	install_element(NAT_NODE, &cfg_nat_ussd_local_cmd);
 	install_element(NAT_NODE, &cfg_nat_use_ipa_for_mgcp_cmd);
 
-	/* access-list */
-	install_element(NAT_NODE, &cfg_lst_imsi_allow_cmd);
-	install_element(NAT_NODE, &cfg_lst_imsi_deny_cmd);
-	install_element(NAT_NODE, &cfg_lst_no_cmd);
+	bsc_msg_lst_vty_init(nat, &nat->access_lists, NAT_NODE);
 
 	/* number rewriting */
 	install_element(NAT_NODE, &cfg_nat_number_rewrite_cmd);
diff --git a/openbsc/src/osmo-bsc_nat/bsc_ussd.c b/openbsc/src/osmo-bsc_nat/bsc_ussd.c
index 67844b8..1082414 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_ussd.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_ussd.c
@@ -22,6 +22,7 @@
 
 #include <openbsc/bsc_nat.h>
 #include <openbsc/bsc_nat_sccp.h>
+#include <openbsc/bsc_msg_filter.h>
 #include <openbsc/ipaccess.h>
 #include <openbsc/socket.h>
 
@@ -350,7 +351,7 @@
 	state->invoke_id = req->invoke_id;
 	memcpy(&state->src_ref, &con->remote_ref, sizeof(con->remote_ref));
 	memcpy(&state->dst_ref, &con->real_ref, sizeof(con->real_ref));
-	memcpy(state->imsi, con->imsi, strlen(con->imsi));
+	memcpy(state->imsi, con->filter_state.imsi, strlen(con->filter_state.imsi));
 
 	/* add additional tag/values */
 	lac = htons(con->lac);
@@ -373,7 +374,7 @@
 	uint8_t proto;
 	uint8_t ti;
 	struct gsm48_hdr *hdr48;
-	struct bsc_nat_acc_lst *lst;
+	struct bsc_msg_acc_lst *lst;
 	struct ussd_request req;
 
 	/*
@@ -381,10 +382,10 @@
 	 * decode if the connection was created for USSD, we do have a USSD access
 	 * list, a query, a IMSI and such...
 	 */
-	if (con->con_type != NAT_CON_TYPE_SSA)
+	if (con->filter_state.con_type != FLT_CON_TYPE_SSA)
 		return 0;
 
-	if (!con->imsi)
+	if (!con->filter_state.imsi)
 		return 0;
 
 	/* We have not verified the IMSI yet */
@@ -399,7 +400,7 @@
 	if (parsed->bssap != BSSAP_MSG_DTAP)
 		return 0;
 
-	if (strlen(con->imsi) >= GSM_IMSI_LENGTH)
+	if (strlen(con->filter_state.imsi) >= GSM_IMSI_LENGTH)
 		return 0;
 
 	hdr48 = bsc_unpack_dtap(parsed, msg, &len);
@@ -415,12 +416,12 @@
 	if (msg_type == GSM0480_MTYPE_REGISTER) {
 
 		/* now check if it is a IMSI we care about */
-		lst = bsc_nat_acc_lst_find(con->bsc->nat,
+		lst = bsc_msg_acc_lst_find(&con->bsc->nat->access_lists,
 					   con->bsc->nat->ussd_lst_name);
 		if (!lst)
 			return 0;
 
-		if (bsc_nat_lst_check_allow(lst, con->imsi) != 0)
+		if (bsc_msg_acc_lst_check_allow(lst, con->filter_state.imsi) != 0)
 			return 0;
 
 		/* now decode the message and see if we really want to handle it */
@@ -435,14 +436,15 @@
 			return 0;
 
 		/* found a USSD query for our subscriber */
-		LOGP(DNAT, LOGL_NOTICE, "Found USSD query for %s\n", con->imsi);
+		LOGP(DNAT, LOGL_NOTICE, "Found USSD query for %s\n",
+			con->filter_state.imsi);
 		con->ussd_ti[ti] = 1;
 		if (forward_ussd(con, &req, msg) != 0)
 			return 0;
 		return 1;
 	} else if (msg_type == GSM0480_MTYPE_FACILITY && con->ussd_ti[ti]) {
 		LOGP(DNAT, LOGL_NOTICE, "Forwarding message part of TI: %d %s\n",
-		     ti, con->imsi);
+		     ti, con->filter_state.imsi);
 		if (forward_ussd_simple(con, msg) != 0)
 			return 0;
 		return 1;
diff --git a/openbsc/tests/bsc-nat/Makefile.am b/openbsc/tests/bsc-nat/Makefile.am
index b620d96..26e5500 100644
--- a/openbsc/tests/bsc-nat/Makefile.am
+++ b/openbsc/tests/bsc-nat/Makefile.am
@@ -10,11 +10,13 @@
 			$(top_srcdir)/src/osmo-bsc_nat/bsc_filter.c \
 			$(top_srcdir)/src/osmo-bsc_nat/bsc_sccp.c \
 			$(top_srcdir)/src/osmo-bsc_nat/bsc_nat_utils.c \
-			$(top_srcdir)/src/osmo-bsc_nat/bsc_nat_filter.c \
 			$(top_srcdir)/src/osmo-bsc_nat/bsc_nat_rewrite.c \
 			$(top_srcdir)/src/osmo-bsc_nat/bsc_nat_rewrite_trie.c \
-			$(top_srcdir)/src/osmo-bsc_nat/bsc_mgcp_utils.c
-bsc_nat_test_LDADD = $(top_builddir)/src/libbsc/libbsc.a \
+			$(top_srcdir)/src/osmo-bsc_nat/bsc_mgcp_utils.c \
+			$(top_srcdir)/src/osmo-bsc_nat/bsc_nat_filter.c
+bsc_nat_test_LDADD = \
+			$(top_builddir)/src/libfilter/libfilter.a \
+			$(top_builddir)/src/libbsc/libbsc.a \
 			$(top_builddir)/src/libmgcp/libmgcp.a \
 			$(top_builddir)/src/libtrau/libtrau.a \
 			$(top_builddir)/src/libcommon/libcommon.a \
diff --git a/openbsc/tests/bsc-nat/bsc_nat_test.c b/openbsc/tests/bsc-nat/bsc_nat_test.c
index 5b01cc3..b830eb0 100644
--- a/openbsc/tests/bsc-nat/bsc_nat_test.c
+++ b/openbsc/tests/bsc-nat/bsc_nat_test.c
@@ -26,6 +26,7 @@
 #include <openbsc/gsm_data.h>
 #include <openbsc/bsc_nat.h>
 #include <openbsc/bsc_nat_sccp.h>
+#include <openbsc/bsc_msg_filter.h>
 #include <openbsc/nat_rewrite_trie.h>
 
 #include <osmocom/core/application.h>
@@ -710,7 +711,7 @@
 		.data = bssmap_cr,
 		.length = sizeof(bssmap_cr),
 		.result = 1,
-		.contype = NAT_CON_TYPE_CM_SERV_REQ,
+		.contype = FLT_CON_TYPE_CM_SERV_REQ,
 		.nat_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.nat_lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.bsc_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
@@ -722,7 +723,7 @@
 		.data = bss_lu,
 		.length = sizeof(bss_lu),
 		.result = 1,
-		.contype = NAT_CON_TYPE_LU,
+		.contype = FLT_CON_TYPE_LU,
 		.nat_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.nat_lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.bsc_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
@@ -734,7 +735,7 @@
 		.data = pag_resp,
 		.length = sizeof(pag_resp),
 		.result = 1,
-		.contype = NAT_CON_TYPE_PAG_RESP,
+		.contype = FLT_CON_TYPE_PAG_RESP,
 		.nat_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.nat_lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.bsc_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
@@ -748,7 +749,7 @@
 		.length = sizeof(bss_lu),
 		.result = -3,
 		.nat_imsi_deny = "[0-9]*",
-		.contype = NAT_CON_TYPE_LU,
+		.contype = FLT_CON_TYPE_LU,
 		.nat_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.nat_lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.bsc_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
@@ -763,7 +764,7 @@
 		.result = 1,
 		.nat_imsi_deny = "[0-9]*",
 		.bsc_imsi_allow = "2440[0-9]*",
-		.contype = NAT_CON_TYPE_LU,
+		.contype = FLT_CON_TYPE_LU,
 		.nat_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.nat_lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.bsc_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
@@ -778,7 +779,7 @@
 		.result = 1,
 		.bsc_imsi_allow = "[0-9]*",
 		.nat_imsi_deny = "[0-9]*",
-		.contype = NAT_CON_TYPE_LU,
+		.contype = FLT_CON_TYPE_LU,
 		.nat_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.nat_lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.bsc_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
@@ -794,7 +795,7 @@
 		.bsc_imsi_deny = "[0-9]*",
 		.bsc_imsi_allow = "[0-9]*",
 		.nat_imsi_deny = "[0-9]*",
-		.contype = NAT_CON_TYPE_LU,
+		.contype = FLT_CON_TYPE_LU,
 		.nat_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.nat_lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.bsc_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
@@ -809,7 +810,7 @@
 		.result = -3,
 		.bsc_imsi_deny = "000[0-9]*",
 		.nat_imsi_deny = "[0-9]*",
-		.contype = NAT_CON_TYPE_LU,
+		.contype = FLT_CON_TYPE_LU,
 		.nat_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.nat_lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.bsc_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
@@ -824,7 +825,7 @@
 		.result = -3,
 		.bsc_imsi_deny = "000[0-9]*",
 		.nat_imsi_deny = "[0-9]*",
-		.contype = NAT_CON_TYPE_LU,
+		.contype = FLT_CON_TYPE_LU,
 		.nat_cm_reject_cause = 0x23,
 		.nat_lu_reject_cause = 0x42,
 		.bsc_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
@@ -838,7 +839,7 @@
 		.length = sizeof(bss_lu),
 		.result = -2,
 		.bsc_imsi_deny = "[0-9]*",
-		.contype = NAT_CON_TYPE_LU,
+		.contype = FLT_CON_TYPE_LU,
 		.nat_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.nat_lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.bsc_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
@@ -852,7 +853,7 @@
 		.length = sizeof(bss_lu),
 		.result = -2,
 		.bsc_imsi_deny = "[0-9]*",
-		.contype = NAT_CON_TYPE_LU,
+		.contype = FLT_CON_TYPE_LU,
 		.nat_cm_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.nat_lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED,
 		.bsc_cm_reject_cause = 0x42,
@@ -867,9 +868,9 @@
 	int i, res, contype;
 	struct msgb *msg = msgb_alloc(4096, "test_cr_filter");
 	struct bsc_nat_parsed *parsed;
-	struct bsc_nat_acc_lst *nat_lst, *bsc_lst;
-	struct bsc_nat_acc_lst_entry *nat_entry, *bsc_entry;
-	struct bsc_nat_reject_cause cause;
+	struct bsc_msg_acc_lst *nat_lst, *bsc_lst;
+	struct bsc_msg_acc_lst_entry *nat_entry, *bsc_entry;
+	struct bsc_filter_reject_cause cause;
 
 	struct bsc_nat *nat = bsc_nat_alloc();
 	struct bsc_connection *bsc = bsc_connection_alloc(nat);
@@ -878,11 +879,11 @@
 	bsc->cfg->acc_lst_name = "bsc";
 	nat->acc_lst_name = "nat";
 
-	nat_lst = bsc_nat_acc_lst_get(nat, "nat");
-	bsc_lst = bsc_nat_acc_lst_get(nat, "bsc");
+	nat_lst = bsc_msg_acc_lst_get(nat, &nat->access_lists, "nat");
+	bsc_lst = bsc_msg_acc_lst_get(nat, &nat->access_lists, "bsc");
 
-	bsc_entry = bsc_nat_acc_lst_entry_create(bsc_lst);
-	nat_entry = bsc_nat_acc_lst_entry_create(nat_lst);
+	bsc_entry = bsc_msg_acc_lst_entry_create(bsc_lst);
+	nat_entry = bsc_msg_acc_lst_entry_create(nat_lst);
 
 	/* test the default value as we are going to overwrite it */
 	OSMO_ASSERT(bsc_entry->cm_reject_cause == GSM48_REJECT_PLMN_NOT_ALLOWED);
@@ -946,7 +947,7 @@
 	int i;
 	struct msgb *msg = msgb_alloc(4096, "test_dt_filter");
 	struct bsc_nat_parsed *parsed;
-	struct bsc_nat_reject_cause cause;
+	struct bsc_filter_reject_cause cause;
 
 	struct bsc_nat *nat = bsc_nat_alloc();
 	struct bsc_connection *bsc = bsc_connection_alloc(nat);
@@ -991,7 +992,7 @@
 		if (!parsed)
 			continue;
 
-		con->imsi_checked = 0;
+		con->filter_state.imsi_checked = 0;
 		memset(&cause, 0, sizeof(cause));
 		bsc_nat_filter_dt(bsc, msg, con, parsed, &cause);
 	}
@@ -1453,21 +1454,21 @@
 	if (lst == NULL)
 		abort();
 
-	rc = bsc_nat_barr_adapt(NULL, &root, lst);
+	rc = bsc_filter_barr_adapt(NULL, &root, lst);
 	if (rc != 0)
 		abort();
 	talloc_free(lst);
 
 
 	for (node = rb_first(&root); node; node = rb_next(node)) {
-		struct bsc_nat_barr_entry *entry;
-		entry = rb_entry(node, struct bsc_nat_barr_entry, node);
+		struct bsc_filter_barr_entry *entry;
+		entry = rb_entry(node, struct bsc_filter_barr_entry, node);
 		printf("IMSI: %s CM: %d LU: %d\n", entry->imsi,
 			entry->cm_reject_cause, entry->lu_reject_cause);
 	}
 
 	/* do the look up now.. */
-	rc = bsc_nat_barr_find(&root, "12123119", &cm, &lu);
+	rc = bsc_filter_barr_find(&root, "12123119", &cm, &lu);
 	if (!rc) {
 		printf("Failed to find the IMSI.\n");
 		abort();
@@ -1479,7 +1480,7 @@
 	}
 
 	/* empty and check that it is empty */
-	bsc_nat_barr_adapt(NULL, &root, NULL);
+	bsc_filter_barr_adapt(NULL, &root, NULL);
 	if (!RB_EMPTY_ROOT(&root)) {
 		printf("Failed to empty the list.\n");
 		abort();
@@ -1492,7 +1493,7 @@
 		abort();
 	}
 
-	rc = bsc_nat_barr_adapt(NULL, &root, lst);
+	rc = bsc_filter_barr_adapt(NULL, &root, lst);
 	if (rc != -1) {
 		printf("It should have failed due dup\n");
 		abort();
@@ -1501,13 +1502,13 @@
 
 	/* dump for reference */
 	for (node = rb_first(&root); node; node = rb_next(node)) {
-		struct bsc_nat_barr_entry *entry;
-		entry = rb_entry(node, struct bsc_nat_barr_entry, node);
+		struct bsc_filter_barr_entry *entry;
+		entry = rb_entry(node, struct bsc_filter_barr_entry, node);
 		printf("IMSI: %s CM: %d LU: %d\n", entry->imsi,
 			entry->cm_reject_cause, entry->lu_reject_cause);
 
 	}
-	rc = bsc_nat_barr_adapt(NULL, &root, NULL);
+	rc = bsc_filter_barr_adapt(NULL, &root, NULL);
 }
 
 static void test_nat_extract_lac()