diff --git a/include/osmocom/hlr/Makefile.am b/include/osmocom/hlr/Makefile.am
index 532fa5d..5c96ec8 100644
--- a/include/osmocom/hlr/Makefile.am
+++ b/include/osmocom/hlr/Makefile.am
@@ -10,5 +10,7 @@
 	hlr_vty_subscr.h \
 	logging.h \
 	lu_fsm.h \
+	mslookup_server.h \
 	rand.h \
+	timestamp.h \
 	$(NULL)
diff --git a/include/osmocom/hlr/hlr.h b/include/osmocom/hlr/hlr.h
index 2214a8b..5a10856 100644
--- a/include/osmocom/hlr/hlr.h
+++ b/include/osmocom/hlr/hlr.h
@@ -68,6 +68,13 @@
 	/* Bitmask of DB_SUBSCR_FLAG_* */
 	uint8_t subscr_create_on_demand_flags;
 	unsigned int subscr_create_on_demand_rand_msisdn_len;
+
+	struct {
+		struct {
+			uint32_t local_attach_max_age;
+			struct llist_head local_site_services;
+		} server;
+	} mslookup;
 };
 
 extern struct hlr *g_hlr;
diff --git a/include/osmocom/hlr/mslookup_server.h b/include/osmocom/hlr/mslookup_server.h
new file mode 100644
index 0000000..6be47dd
--- /dev/null
+++ b/include/osmocom/hlr/mslookup_server.h
@@ -0,0 +1,66 @@
+/* Copyright 2019 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
+ *
+ * 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/>.
+ *
+ */
+
+#pragma once
+
+struct osmo_mslookup_query;
+struct osmo_mslookup_result;
+
+/*! mslookup service name used for roaming/proxying between osmo-hlr instances. */
+#define OSMO_MSLOOKUP_SERVICE_HLR_GSUP "gsup.hlr"
+
+/*! What addresses to return to mslookup queries when a subscriber is attached at the local site.
+ * Mapping of service name to IP address and port. This corresponds to the VTY config for
+ * 'mslookup' / 'server' [/ 'msc MSC-1-2-3'] / 'service sip.voice at 1.2.3.4 1234'.
+ */
+struct mslookup_service_host {
+	struct llist_head entry;
+	char service[OSMO_MSLOOKUP_SERVICE_MAXLEN+1];
+	struct osmo_sockaddr_str host_v4;
+	struct osmo_sockaddr_str host_v6;
+};
+
+/*! Sets of mslookup_service_host per connected MSC.
+ * When there are more than one MSC connected to this osmo-hlr, this allows keeping separate sets of service addresses
+ * for each MSC. The entry with mslookup_server_msc_wildcard as MSC name is used for all MSCs (if no match for that
+ * particular MSC is found). This corresponds to the VTY config for
+ * 'mslookup' / 'server' / 'msc MSC-1-2-3'.
+ */
+struct mslookup_server_msc_cfg {
+	struct llist_head entry;
+	struct osmo_ipa_name name;
+	struct llist_head service_hosts;
+};
+
+struct mslookup_service_host *mslookup_server_service_get(const struct osmo_ipa_name *msc_name, const char *service);
+
+struct mslookup_service_host *mslookup_server_msc_service_get(struct mslookup_server_msc_cfg *msc, const char *service,
+							      bool create);
+int mslookup_server_msc_service_set(struct mslookup_server_msc_cfg *msc, const char *service,
+				    const struct osmo_sockaddr_str *addr);
+int mslookup_server_msc_service_del(struct mslookup_server_msc_cfg *msc, const char *service,
+				    const struct osmo_sockaddr_str *addr);
+
+extern const struct osmo_ipa_name mslookup_server_msc_wildcard;
+struct mslookup_server_msc_cfg *mslookup_server_msc_get(const struct osmo_ipa_name *msc_name, bool create);
+
+
+struct mslookup_service_host *mslookup_server_get_local_gsup_addr();
+void mslookup_server_rx(const struct osmo_mslookup_query *query,
+			     struct osmo_mslookup_result *result);
diff --git a/include/osmocom/hlr/timestamp.h b/include/osmocom/hlr/timestamp.h
new file mode 100644
index 0000000..9708985
--- /dev/null
+++ b/include/osmocom/hlr/timestamp.h
@@ -0,0 +1,28 @@
+/* Copyright 2019 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
+ *
+ * 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/>.
+ *
+ */
+
+#pragma once
+
+#include <sys/time.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+typedef time_t timestamp_t;
+void timestamp_update(timestamp_t *timestamp);
+bool timestamp_age(const timestamp_t *timestamp, uint32_t *age);