dgsm: osmo-hlr is opening mDNS server and client sockets

Change-Id: I377b3bab7334c3212e40c4cf19aa223ac1be1644

21 files changed, 824 insertions, 311 deletions

diff --git a/sql/hlr.sql b/sql/hlr.sql
index b951632..1bfd86f 100644
--- a/sql/hlr.sql
+++ b/sql/hlr.sql
@@ -45,7 +45,8 @@ CREATE TABLE subscriber (
 	last_lu_seen TIMESTAMP default NULL,
 	-- When a LU was received via a proxy, that proxy's hlr_number is stored here,
 	-- while vlr_number reflects the MSC on the far side of that proxy.
-	vlr_via_proxy	VARCHAR
+	vlr_via_proxy	VARCHAR,
+	sgsn_via_proxy	VARCHAR
 );
 
 CREATE TABLE subscriber_apn (
diff --git a/src/Makefile.am b/src/Makefile.am
index 1b8e85c..3485ce6 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -42,6 +42,8 @@ noinst_HEADERS = \
 	dgsm.h \
 	remote_hlr.h \
 	global_title.h \
+	mslookup_server.h \
+	mslookup_server_mdns.h \
 	$(NULL)
 
 bin_PROGRAMS = \
@@ -71,6 +73,7 @@ osmo_hlr_SOURCES = \
 	dgsm_vty.c \
 	remote_hlr.c \
 	mslookup_server.c \
+	mslookup_server_mdns.c \
 	global_title.c \
 	$(NULL)
 
diff --git a/src/db.c b/src/db.c
index 4fcbad2..4d62aa0 100644
--- a/src/db.c
+++ b/src/db.c
@@ -47,7 +47,8 @@
 	"ms_purged_cs," \
 	"ms_purged_ps," \
 	"last_lu_seen," \
-	"vlr_via_proxy"
+	"vlr_via_proxy," \
+	"sgsn_via_proxy"
 
 static const char *stmt_sql[] = {
 	[DB_STMT_SEL_BY_IMSI] = "SELECT " SEL_COLUMNS " FROM subscriber WHERE imsi = ?",
@@ -55,7 +56,7 @@ static const char *stmt_sql[] = {
 	[DB_STMT_SEL_BY_ID] = "SELECT " SEL_COLUMNS " FROM subscriber WHERE id = ?",
 	[DB_STMT_SEL_BY_IMEI] = "SELECT " SEL_COLUMNS " FROM subscriber WHERE imei = ?",
 	[DB_STMT_UPD_VLR_BY_ID] = "UPDATE subscriber SET vlr_number = $number, vlr_via_proxy = $proxy WHERE id = $subscriber_id",
-	[DB_STMT_UPD_SGSN_BY_ID] = "UPDATE subscriber SET sgsn_number = $number WHERE id = $subscriber_id",
+	[DB_STMT_UPD_SGSN_BY_ID] = "UPDATE subscriber SET sgsn_number = $number, sgsn_via_proxy = $proxy WHERE id = $subscriber_id",
 	[DB_STMT_UPD_IMEI_BY_IMSI] = "UPDATE subscriber SET imei = $imei WHERE imsi = $imsi",
 	[DB_STMT_AUC_BY_IMSI] =
 		"SELECT id, algo_id_2g, ki, algo_id_3g, k, op, opc, sqn, ind_bitlen"
@@ -456,6 +457,7 @@ static int db_upgrade_v4(struct db_context *dbc)
 	int rc;
 	const char *statements[] = {
 		"ALTER TABLE subscriber ADD COLUMN vlr_via_proxy VARCHAR",
+		"ALTER TABLE subscriber ADD COLUMN sgsn_via_proxy VARCHAR",
 		"PRAGMA user_version = 4",
 	};
 
diff --git a/src/db.h b/src/db.h
index ce11e11..3f7e5c4 100644
--- a/src/db.h
+++ b/src/db.h
@@ -185,5 +185,5 @@ int hlr_subscr_nam(struct hlr *hlr, struct hlr_subscriber *subscr, bool nam_val,
 #define copy_sqlite3_text_to_gt(gt, stmt, idx) \
 	do { \
 		const char *_txt = (const char *) sqlite3_column_text(stmt, idx); \
-		global_title_set(gt, (uint8_t*)_txt, _txt ? strlen(_txt)+1 : 0); \
+		global_title_set_str(gt, _txt); \
 	} while (0)
diff --git a/src/db_hlr.c b/src/db_hlr.c
index af1e1b2..8d606f8 100644
--- a/src/db_hlr.c
+++ b/src/db_hlr.c
@@ -739,15 +739,14 @@ int db_subscr_lu(struct db_context *dbc, int64_t subscr_id,
 	if (!db_bind_text(stmt, "$number", (char*)vlr_or_sgsn_number->val))
 		return -EIO;
 
-	if (!is_ps) {
-		if (gsup_peer && gsup_peer->len
-		    && global_title_cmp(gsup_peer, vlr_or_sgsn_number)) {
-			if (!db_bind_text(stmt, "$proxy", (char*)gsup_peer->val))
-				return -EIO;
-		} else {
-			if (!db_bind_null(stmt, "$proxy"))
-				return -EIO;
-		}
+	/* If the VLR/SGSN is not the direct GSUP peer, the gsup_peer is a proxy towards the actual VLR/SGSN.
+	 * -> store the gsup_peer as proxy only when it differs from the vlr_or_sgsn_number. */
+	if (global_title_cmp(gsup_peer, vlr_or_sgsn_number)) {
+		if (!db_bind_text(stmt, "$proxy", (char*)gsup_peer->val))
+			return -EIO;
+	} else {
+		if (!db_bind_null(stmt, "$proxy"))
+			return -EIO;
 	}
 
 	/* execute the statement */
diff --git a/src/dgsm.c b/src/dgsm.c
index 0482523..a91ffc0 100644
--- a/src/dgsm.c
+++ b/src/dgsm.c
@@ -1,7 +1,7 @@
 #include <errno.h>
 #include <osmocom/core/logging.h>
 #include <osmocom/mslookup/mslookup_client.h>
-#include <osmocom/mslookup/mslookup_client_dns.h>
+#include <osmocom/mslookup/mslookup_client_mdns.h>
 #include <osmocom/gsupclient/gsup_client.h>
 #include "logging.h"
 #include "hlr.h"
@@ -10,36 +10,25 @@
 #include "dgsm.h"
 #include "proxy.h"
 #include "remote_hlr.h"
-#include "mslookup_server.h"
+#include "mslookup_server_mdns.h"
+#include "global_title.h"
 
 #define LOG_DGSM(imsi, level, fmt, args...) \
 	LOGP(DDGSM, level, "(IMSI-%s) " fmt, imsi, ##args)
 
 void *dgsm_ctx = NULL;
-struct dgsm_config dgsm_config = {
-	.server = {
-		.dns = {
-			.multicast_bind_addr = {
-				.ip = OSMO_MSLOOKUP_MDNS_IP4,
-				.port = OSMO_MSLOOKUP_MDNS_PORT,
-			},
-		},
-	},
-};
 
+const struct global_title dgsm_config_msc_wildcard = {};
 
-struct dgsm_msc_config *dgsm_config_msc_get(const uint8_t *ipa_unit_name, size_t ipa_unit_name_len,
-					    bool create)
+struct dgsm_msc_config *dgsm_config_msc_get(const struct global_title *msc_name, bool create)
 {
 	struct dgsm_msc_config *msc;
 
-	if (!ipa_unit_name)
+	if (!msc_name)
 		return NULL;
 
-	llist_for_each_entry(msc, &dgsm_config.server.msc_configs, entry) {
-		if (ipa_unit_name_len != msc->unit_name_len)
-			continue;
-		if (memcmp(ipa_unit_name, msc->unit_name, ipa_unit_name_len))
+	llist_for_each_entry(msc, &g_hlr->mslookup.vty.server.msc_configs, entry) {
+		if (global_title_cmp(&msc->name, msc_name))
 			continue;
 		return msc;
 	}
@@ -48,18 +37,18 @@ struct dgsm_msc_config *dgsm_config_msc_get(const uint8_t *ipa_unit_name, size_t
 
 	msc = talloc_zero(dgsm_ctx, struct dgsm_msc_config);
 	OSMO_ASSERT(msc);
-	INIT_LLIST_HEAD(&msc->service_addrs);
-	msc->unit_name = talloc_memdup(msc, ipa_unit_name, ipa_unit_name_len);
-	OSMO_ASSERT(msc->unit_name);
-	msc->unit_name_len = ipa_unit_name_len;
+	INIT_LLIST_HEAD(&msc->service_hosts);
+	msc->name = *msc_name;
 	return msc;
 }
 
-static struct dgsm_service_addr *dgsm_config_msc_service_get(struct dgsm_msc_config *msc, const char *service,
-							     bool create)
+struct dgsm_service_host *dgsm_config_msc_service_get(struct dgsm_msc_config *msc, const char *service, bool create)
 {
-	struct dgsm_service_addr *e;
-	llist_for_each_entry(e, &msc->service_addrs, entry) {
+	struct dgsm_service_host *e;
+	if (!msc)
+		return NULL;
+
+	llist_for_each_entry(e, &msc->service_hosts, entry) {
 		if (!strcmp(e->service, service))
 			return e;
 	}
@@ -67,27 +56,24 @@ static struct dgsm_service_addr *dgsm_config_msc_service_get(struct dgsm_msc_con
 	if (!create)
 		return NULL;
 
-	e = talloc_zero(msc, struct dgsm_service_addr);
+	e = talloc_zero(msc, struct dgsm_service_host);
 	OSMO_ASSERT(e);
 	OSMO_STRLCPY_ARRAY(e->service, service);
-	llist_add_tail(&e->entry, &msc->service_addrs);
+	llist_add_tail(&e->entry, &msc->service_hosts);
 	return e;
 }
 
-struct dgsm_service_addr *dgsm_config_service_get(const uint8_t *ipa_unit_name, size_t ipa_unit_name_len,
-						  const char *service)
+struct dgsm_service_host *dgsm_config_service_get(const struct global_title *msc_name, const char *service)
 {
-	struct dgsm_msc_config *msc = dgsm_config_msc_get(ipa_unit_name, ipa_unit_name_len, false);
+	struct dgsm_msc_config *msc = dgsm_config_msc_get(msc_name, false);
 	if (!msc)
 		return NULL;
 	return dgsm_config_msc_service_get(msc, service, false);
 }
 
-int dgsm_config_service_set(const uint8_t *ipa_unit_name, size_t ipa_unit_name_len,
-			    const char *service, const struct osmo_sockaddr_str *addr)
+int dgsm_config_msc_service_set(struct dgsm_msc_config *msc, const char *service, const struct osmo_sockaddr_str *addr)
 {
-	struct dgsm_msc_config *msc;
-	struct dgsm_service_addr *e;
+	struct dgsm_service_host *e;
 
 	if (!service || !service[0]
 	    || strlen(service) > OSMO_MSLOOKUP_SERVICE_MAXLEN)
@@ -95,20 +81,16 @@ int dgsm_config_service_set(const uint8_t *ipa_unit_name, size_t ipa_unit_name_l
 	if (!addr || !osmo_sockaddr_str_is_nonzero(addr))
 		return -EINVAL;
 
-	msc = dgsm_config_msc_get(ipa_unit_name, ipa_unit_name_len, true);
-	if (!msc)
-		return -EINVAL;
-
 	e = dgsm_config_msc_service_get(msc, service, true);
 	if (!e)
 		return -EINVAL;
 
 	switch (addr->af) {
 	case AF_INET:
-		e->addr_v4 = *addr;
+		e->host_v4 = *addr;
 		break;
 	case AF_INET6:
-		e->addr_v6 = *addr;
+		e->host_v6 = *addr;
 		break;
 	default:
 		return -EINVAL;
@@ -116,30 +98,38 @@ int dgsm_config_service_set(const uint8_t *ipa_unit_name, size_t ipa_unit_name_l
 	return 0;
 }
 
-int dgsm_config_service_del(const uint8_t *ipa_unit_name, size_t ipa_unit_name_len,
-			    const char *service, const struct osmo_sockaddr_str *addr)
+int dgsm_config_service_set(const struct global_title *msc_name, const char *service, const struct osmo_sockaddr_str *addr)
 {
 	struct dgsm_msc_config *msc;
-	struct dgsm_service_addr *e, *n;
 
-	msc = dgsm_config_msc_get(ipa_unit_name, ipa_unit_name_len, false);
+	msc = dgsm_config_msc_get(msc_name, true);
+	if (!msc)
+		return -EINVAL;
+
+	return dgsm_config_msc_service_set(msc, service, addr);
+}
+
+int dgsm_config_msc_service_del(struct dgsm_msc_config *msc, const char *service, const struct osmo_sockaddr_str *addr)
+{
+	struct dgsm_service_host *e, *n;
+
 	if (!msc)
 		return -ENOENT;
 
-	llist_for_each_entry_safe(e, n, &msc->service_addrs, entry) {
+	llist_for_each_entry_safe(e, n, &msc->service_hosts, entry) {
 		if (service && strcmp(service, e->service))
 			continue;
 
 		if (addr) {
-			if (!osmo_sockaddr_str_cmp(addr, &e->addr_v4)) {
-				e->addr_v4 = (struct osmo_sockaddr_str){};
+			if (!osmo_sockaddr_str_cmp(addr, &e->host_v4)) {
+				e->host_v4 = (struct osmo_sockaddr_str){};
 				/* Removed one addr. If the other is still there, keep the entry. */
-				if (osmo_sockaddr_str_is_nonzero(&e->addr_v6))
+				if (osmo_sockaddr_str_is_nonzero(&e->host_v6))
 					continue;
-			} else if (!osmo_sockaddr_str_cmp(addr, &e->addr_v6)) {
-				e->addr_v6 = (struct osmo_sockaddr_str){};
+			} else if (!osmo_sockaddr_str_cmp(addr, &e->host_v6)) {
+				e->host_v6 = (struct osmo_sockaddr_str){};
 				/* Removed one addr. If the other is still there, keep the entry. */
-				if (osmo_sockaddr_str_is_nonzero(&e->addr_v4))
+				if (osmo_sockaddr_str_is_nonzero(&e->host_v4))
 					continue;
 			} else
 				/* No addr match, keep the entry. */
@@ -152,8 +142,14 @@ int dgsm_config_service_del(const uint8_t *ipa_unit_name, size_t ipa_unit_name_l
 	return 0;
 }
 
+int dgsm_config_service_del(const struct global_title *msc_name,
+			    const char *service, const struct osmo_sockaddr_str *addr)
+{
+	return dgsm_config_msc_service_del(dgsm_config_msc_get(msc_name, false),
+					   service, addr);
+}
+
 static void *dgsm_pending_messages_ctx = NULL;
-static struct osmo_mslookup_client *mslookup_client = NULL;
 
 struct pending_gsup_message {
 	struct llist_head entry;
@@ -212,13 +208,16 @@ void dgsm_send_to_remote_hlr(const struct proxy_subscr *ps, const struct osmo_gs
 /* Return true when the message has been handled by D-GSM. */
 bool dgsm_check_forward_gsup_msg(struct osmo_gsup_conn *conn, const struct osmo_gsup_message *gsup)
 {
-	const struct proxy_subscr *ps;
+	const struct proxy_subscr *proxy_subscr;
 	struct proxy_subscr ps_new;
 	struct gsup_route *r;
 	struct osmo_gsup_message gsup_copy;
+	struct proxy *proxy = g_hlr->gsup_proxy.cs;
+	if (gsup->cn_domain == OSMO_GSUP_CN_DOMAIN_PS)
+		proxy = g_hlr->gsup_proxy.ps;
 
-	ps = proxy_subscr_get(gsup->imsi);
-	if (ps)
+	proxy_subscr = proxy_subscr_get_by_imsi(proxy, gsup->imsi);
+	if (proxy_subscr)
 		goto yes_we_are_proxying;
 
 	/* No proxy entry exists. If the IMSI is known in the local HLR, then we won't proxy. */
@@ -232,11 +231,11 @@ bool dgsm_check_forward_gsup_msg(struct osmo_gsup_conn *conn, const struct osmo_
 	/* Add a proxy entry without a remote address to indicate that we are busy querying for a remote HLR. */
 	ps_new = (struct proxy_subscr){};
 	OSMO_STRLCPY_ARRAY(ps_new.imsi, gsup->imsi);
-	proxy_subscr_update(&ps_new);
-	ps = &ps_new;
+	proxy_subscr_update(proxy, &ps_new);
+	proxy_subscr = &ps_new;
 
 yes_we_are_proxying:
-	OSMO_ASSERT(ps);
+	OSMO_ASSERT(proxy_subscr);
 
 	/* To forward to a remote HLR, we need to indicate the source MSC's name to make sure the reply can be routed
 	 * back. Store the sender MSC in gsup->source_name -- the remote HLR is required to return this as
@@ -254,7 +253,7 @@ yes_we_are_proxying:
 	gsup_copy.source_name = r->addr;
 	gsup_copy.source_name_len = talloc_total_size(r->addr);
 
-	dgsm_send_to_remote_hlr(ps, &gsup_copy);
+	dgsm_send_to_remote_hlr(proxy_subscr, &gsup_copy);
 	return true;
 }
 
@@ -263,62 +262,96 @@ void dgsm_init(void *ctx)
 {
 	dgsm_ctx = talloc_named_const(ctx, 0, "dgsm");
 	dgsm_pending_messages_ctx = talloc_named_const(dgsm_ctx, 0, "dgsm_pending_messages");
-	INIT_LLIST_HEAD(&dgsm_config.server.msc_configs);
+	INIT_LLIST_HEAD(&g_hlr->mslookup.vty.server.msc_configs);
+	osmo_sockaddr_str_from_str(&g_hlr->mslookup.vty.server.mdns.bind_addr,
+				   OSMO_MSLOOKUP_MDNS_IP4, OSMO_MSLOOKUP_MDNS_PORT);
+	osmo_sockaddr_str_from_str(&g_hlr->mslookup.vty.client.mdns.query_addr,
+				   OSMO_MSLOOKUP_MDNS_IP4, OSMO_MSLOOKUP_MDNS_PORT);
 }
 
 void dgsm_start(void *ctx)
 {
-	mslookup_client = osmo_mslookup_client_new(dgsm_ctx);
-	OSMO_ASSERT(mslookup_client);
+	g_hlr->mslookup.client.client = osmo_mslookup_client_new(dgsm_ctx);
+	OSMO_ASSERT(g_hlr->mslookup.client.client);
+	g_hlr->mslookup.allow_startup = true;
+	dgsm_config_apply();
 }
 
-void dgsm_dns_server_config_apply()
+static void dgsm_mdns_server_config_apply()
 {
-	/* Check whether to start/stop/restart DNS server */
-	bool should_run = dgsm_config.server.enable && dgsm_config.server.dns.enable;
-	bool should_stop = g_hlr->mslookup.server.dns
+	/* Check whether to start/stop/restart mDNS server */
+	bool should_run;
+	bool should_stop;
+	if (!g_hlr->mslookup.allow_startup)
+		return;
+
+	g_hlr->mslookup.server.max_age = g_hlr->mslookup.vty.server.max_age;
+	
+	should_run = g_hlr->mslookup.vty.server.enable && g_hlr->mslookup.vty.server.mdns.enable;
+	should_stop = g_hlr->mslookup.server.mdns
 		&& (!should_run
-		    || osmo_sockaddr_str_cmp(&dgsm_config.server.dns.multicast_bind_addr,
-					     &g_hlr->mslookup.server.dns->multicast_bind_addr));
+		    || osmo_sockaddr_str_cmp(&g_hlr->mslookup.vty.server.mdns.bind_addr,
+					     &g_hlr->mslookup.server.mdns->bind_addr));
 
 	if (should_stop) {
-		osmo_mslookup_server_dns_stop(g_hlr->mslookup.server.dns);
-		LOGP(DDGSM, LOGL_ERROR, "Stopped MS Lookup DNS server\n");
+		osmo_mslookup_server_mdns_stop(g_hlr->mslookup.server.mdns);
+		g_hlr->mslookup.server.mdns = NULL;
+		LOGP(DDGSM, LOGL_NOTICE, "Stopped mslookup mDNS server\n");
 	}
 
-	if (should_run) {
-		g_hlr->mslookup.server.dns =
-			osmo_mslookup_server_dns_start(&dgsm_config.server.dns.multicast_bind_addr);
-		if (!g_hlr->mslookup.server.dns)
-			LOGP(DDGSM, LOGL_ERROR, "Failed to start MS Lookup DNS server\n");
+	if (should_run && !g_hlr->mslookup.server.mdns) {
+		g_hlr->mslookup.server.mdns =
+			osmo_mslookup_server_mdns_start(g_hlr, &g_hlr->mslookup.vty.server.mdns.bind_addr);
+		if (!g_hlr->mslookup.server.mdns)
+			LOGP(DDGSM, LOGL_ERROR, "Failed to start mslookup mDNS server on " OSMO_SOCKADDR_STR_FMT "\n",
+			     OSMO_SOCKADDR_STR_FMT_ARGS(&g_hlr->mslookup.server.mdns->bind_addr));
 		else
-			LOGP(DDGSM, LOGL_ERROR, "Started MS Lookup DNS server on " OSMO_SOCKADDR_STR_FMT "\n",
-			     OSMO_SOCKADDR_STR_FMT_ARGS(&g_hlr->mslookup.server.dns->multicast_bind_addr));
+			LOGP(DDGSM, LOGL_NOTICE, "Started mslookup mDNS server, receiving mDNS requests at multicast "
+			     OSMO_SOCKADDR_STR_FMT "\n",
+			     OSMO_SOCKADDR_STR_FMT_ARGS(&g_hlr->mslookup.server.mdns->bind_addr));
 	}
 }
 
-void dgsm_dns_client_config_apply()
+static void dgsm_mdns_client_config_apply()
 {
-	/* Check whether to start/stop/restart DNS client */
-	struct osmo_mslookup_client_method *dns_method = g_hlr->mslookup.client.dns;
-	const struct osmo_sockaddr_str *current_bind_addr = osmo_mslookup_client_method_dns_get_bind_addr(dns_method);
+	if (!g_hlr->mslookup.allow_startup)
+		return;
 
-	bool should_run = dgsm_config.client.enable && dgsm_config.client.dns.enable;
-	bool should_stop = dns_method &&
+	/* Check whether to start/stop/restart mDNS client */
+	const struct osmo_sockaddr_str *current_bind_addr;
+	current_bind_addr = osmo_mslookup_client_method_mdns_get_bind_addr(g_hlr->mslookup.client.mdns);
+
+	bool should_run = g_hlr->mslookup.vty.client.enable && g_hlr->mslookup.vty.client.mdns.enable;
+	bool should_stop = g_hlr->mslookup.client.mdns &&
 		(!should_run
-		 || osmo_sockaddr_str_cmp(&dgsm_config.client.dns.multicast_query_addr,
+		 || osmo_sockaddr_str_cmp(&g_hlr->mslookup.vty.client.mdns.query_addr,
 					  current_bind_addr));
 
-	if (should_stop) 
-		osmo_mslookup_client_method_del(mslookup_client, dns_method);
-	if (should_run) {
-		if (osmo_mslookup_client_add_dns(mslookup_client,
-						 dgsm_config.client.dns.multicast_query_addr.ip,
-						 dgsm_config.client.dns.multicast_query_addr.port,
-						 true))
-			LOGP(DDGSM, LOGL_ERROR, "Failed to start MS Lookup DNS client\n");
+	if (should_stop) {
+		osmo_mslookup_client_method_del(g_hlr->mslookup.client.client, g_hlr->mslookup.client.mdns);
+		g_hlr->mslookup.client.mdns = NULL;
+		LOGP(DDGSM, LOGL_NOTICE, "Stopped mslookup mDNS client\n");
+	}
+
+	if (should_run && !g_hlr->mslookup.client.mdns) {
+		g_hlr->mslookup.client.mdns =
+			osmo_mslookup_client_add_mdns(g_hlr->mslookup.client.client,
+						      g_hlr->mslookup.vty.client.mdns.query_addr.ip,
+						      g_hlr->mslookup.vty.client.mdns.query_addr.port,
+						      true);
+		if (!g_hlr->mslookup.client.mdns)
+			LOGP(DDGSM, LOGL_ERROR, "Failed to start mslookup mDNS client with target "
+			     OSMO_SOCKADDR_STR_FMT "\n",
+			     OSMO_SOCKADDR_STR_FMT_ARGS(&g_hlr->mslookup.vty.client.mdns.query_addr));
 		else
-			LOGP(DDGSM, LOGL_ERROR, "Started MS Lookup DNS client with " OSMO_SOCKADDR_STR_FMT "\n",
-			     OSMO_SOCKADDR_STR_FMT_ARGS(&dgsm_config.client.dns.multicast_query_addr));
+			LOGP(DDGSM, LOGL_NOTICE, "Started mslookup mDNS client, sending mDNS requests to multicast " OSMO_SOCKADDR_STR_FMT "\n",
+			     OSMO_SOCKADDR_STR_FMT_ARGS(&g_hlr->mslookup.vty.client.mdns.query_addr));
 	}
 }
+
+void dgsm_config_apply()
+{
+	dgsm_mdns_server_config_apply();
+	dgsm_mdns_client_config_apply();
+}
+
diff --git a/src/dgsm.h b/src/dgsm.h
index 22486c8..704a225 100644
--- a/src/dgsm.h
+++ b/src/dgsm.h
@@ -2,32 +2,40 @@
 
 #include <osmocom/mslookup/mslookup.h>
 #include "gsup_server.h"
+#include "global_title.h"
+
+struct vty;
 
 extern void *dgsm_ctx;
 
-struct dgsm_service_addr {
+struct dgsm_service_host {
 	struct llist_head entry;
 	char service[OSMO_MSLOOKUP_SERVICE_MAXLEN+1];
-	struct osmo_sockaddr_str addr_v4;
-	struct osmo_sockaddr_str addr_v6;
+	struct osmo_sockaddr_str host_v4;
+	struct osmo_sockaddr_str host_v6;
 };
 
 struct dgsm_msc_config {
 	struct llist_head entry;
-	uint8_t *unit_name;
-	size_t unit_name_len;
-	struct llist_head service_addrs;
+	struct global_title name;
+	struct llist_head service_hosts;
 };
 
+/* "Sketch pad" where the VTY can store config items without yet applying. The changes will be applied by e.g.
+ * dgsm_mdns_server_config_apply() and dgsm_mdns_client_config_apply(). */
 struct dgsm_config {
 	struct {
 		/* Whether to listen for incoming MS Lookup requests */
 		bool enable;
 
+		/* If we have a local record of a LU, but it is older than max_age (in seconds),
+		 * do not send it as mslookup result. */
+		uint32_t max_age;
+
 		struct {
 			bool enable;
-			struct osmo_sockaddr_str multicast_bind_addr;
-		} dns;
+			struct osmo_sockaddr_str bind_addr;
+		} mdns;
 
 		struct llist_head msc_configs;
 	} server;
@@ -35,30 +43,31 @@ struct dgsm_config {
 	struct {
 		/* Whether to ask remote HLRs via MS Lookup if an IMSI is not known locally. */
 		bool enable;
+		struct timeval timeout;
 
 		struct {
 			/* Whether to use mDNS for IMSI MS Lookup */
 			bool enable;
-			struct osmo_sockaddr_str multicast_query_addr;
-		} dns;
+			struct osmo_sockaddr_str query_addr;
+		} mdns;
 	} client;
 };
 
-extern struct dgsm_config dgsm_config;
-void dgsm_dns_server_config_apply();
-void dgsm_dns_client_config_apply();
+void dgsm_config_apply();
+
+struct dgsm_service_host *dgsm_config_service_get(const struct global_title *msc_name, const char *service);
+int dgsm_config_service_set(const struct global_title *msc_name, const char *service, const struct osmo_sockaddr_str *addr);
+int dgsm_config_service_del(const struct global_title *msc_name, const char *service, const struct osmo_sockaddr_str *addr);
 
-struct dgsm_service_addr *dgsm_config_service_get(const uint8_t *ipa_unit_name, size_t ipa_unit_name_len,
-						  const char *service);
-int dgsm_config_service_set(const uint8_t *ipa_unit_name, size_t ipa_unit_name_len,
-			    const char *service, const struct osmo_sockaddr_str *addr);
-int dgsm_config_service_del(const uint8_t *ipa_unit_name, size_t ipa_unit_name_len,
-			    const char *service, const struct osmo_sockaddr_str *addr);
+struct dgsm_service_host *dgsm_config_msc_service_get(struct dgsm_msc_config *msc, const char *service, bool create);
+int dgsm_config_msc_service_set(struct dgsm_msc_config *msc, const char *service, const struct osmo_sockaddr_str *addr);
+int dgsm_config_msc_service_del(struct dgsm_msc_config *msc, const char *service, const struct osmo_sockaddr_str *addr);
 
-struct dgsm_msc_config *dgsm_config_msc_get(const uint8_t *ipa_unit_name, size_t ipa_unit_name_len,
-					    bool create);
+extern const struct global_title dgsm_config_msc_wildcard;
+struct dgsm_msc_config *dgsm_config_msc_get(const struct global_title *msc_name, bool create);
 
 void dgsm_init(void *ctx);
+void dgsm_start(void *ctx);
 bool dgsm_check_forward_gsup_msg(struct osmo_gsup_conn *conn, const struct osmo_gsup_message *gsup);
 
 void dgsm_vty_init();
diff --git a/src/dgsm_vty.c b/src/dgsm_vty.c
index 4567be9..c3da81e 100644
--- a/src/dgsm_vty.c
+++ b/src/dgsm_vty.c
@@ -3,8 +3,6 @@
 #include "hlr_vty.h"
 #include "dgsm.h"
 
-static struct dgsm_config dgsm_config_vty = {};
-
 struct cmd_node mslookup_node = {
 	MSLOOKUP_NODE,
 	"%s(config-mslookup)# ",
@@ -17,29 +15,30 @@ DEFUN(cfg_mslookup,
       "Configure Distributed GSM / multicast MS Lookup")
 {
 	vty->node = MSLOOKUP_NODE;
-	printf("%s vty->node = %d\n", __func__, vty->node);
 	return CMD_SUCCESS;
 }
 
-DEFUN(cfg_mslookup_dns,
-      cfg_mslookup_dns_cmd,
-      "dns",
+DEFUN(cfg_mslookup_mdns,
+      cfg_mslookup_mdns_cmd,
+      "mdns",
       "Convenience shortcut: enable both server and client for DNS/mDNS MS Lookup with default config\n")
 {
-	dgsm_config_vty.server.enable = true;
-	dgsm_config_vty.server.dns.enable = true;
-	dgsm_config_vty.client.enable = true;
-	dgsm_config_vty.client.dns.enable = true;
+	g_hlr->mslookup.vty.server.enable = true;
+	g_hlr->mslookup.vty.server.mdns.enable = true;
+	g_hlr->mslookup.vty.client.enable = true;
+	g_hlr->mslookup.vty.client.mdns.enable = true;
+	dgsm_config_apply();
 	return CMD_SUCCESS;
 }
 
-DEFUN(cfg_mslookup_no_dns,
-      cfg_mslookup_no_dns_cmd,
-      "no dns",
+DEFUN(cfg_mslookup_no_mdns,
+      cfg_mslookup_no_mdns_cmd,
+      "no mdns",
       NO_STR "Disable both server and client for DNS/mDNS MS Lookup\n")
 {
-	dgsm_config_vty.server.dns.enable = false;
-	dgsm_config_vty.client.dns.enable = false;
+	g_hlr->mslookup.vty.server.mdns.enable = false;
+	g_hlr->mslookup.vty.client.mdns.enable = false;
+	dgsm_config_apply();
 	return CMD_SUCCESS;
 }
 
@@ -55,8 +54,8 @@ DEFUN(cfg_mslookup_server,
       "Enable and configure Distributed GSM / multicast MS Lookup server")
 {
 	vty->node = MSLOOKUP_SERVER_NODE;
-	dgsm_config_vty.server.enable = true;
-	printf("%s vty->node = %d\n", __func__, vty->node);
+	g_hlr->mslookup.vty.server.enable = true;
+	dgsm_config_apply();
 	return CMD_SUCCESS;
 }
 
@@ -65,41 +64,45 @@ DEFUN(cfg_mslookup_no_server,
       "no server",
       NO_STR "Disable Distributed GSM / multicast MS Lookup server")
 {
-	dgsm_config_vty.server.enable = false;
+	g_hlr->mslookup.vty.server.enable = false;
+	dgsm_config_apply();
 	return CMD_SUCCESS;
 }
 
-#define DNS_STR "Configure DNS/mDNS MS Lookup\n"
-#define DNS_BIND_STR DNS_STR "Configure where the DNS/mDNS server listens for MS Lookup requests\n"
+#define MDNS_STR "Configure mslookup by multicast DNS\n"
+#define MDNS_BIND_STR MDNS_STR "Configure where the mDNS server listens for MS Lookup requests\n"
 #define IP46_STR "IPv4 address like 1.2.3.4 or IPv6 address like a:b:c:d::1\n"
 #define PORT_STR "Port number\n"
 
-DEFUN(cfg_mslookup_server_dns_bind_multicast,
-      cfg_mslookup_server_dns_bind_multicast_cmd,
-      "dns bind multicast IP <1-65535>",
-      DNS_BIND_STR "Configure mDNS multicast listen address\n" IP46_STR PORT_STR)
+DEFUN(cfg_mslookup_server_mdns_bind,
+      cfg_mslookup_server_mdns_bind_cmd,
+      "mdns [bind] [IP] [<1-65535>]",
+      MDNS_BIND_STR IP46_STR PORT_STR)
 {
-	const char *ip_str = argv[1];
-	const char *port_str = argv[2];
+	const char *ip_str = argc > 1? argv[1] : g_hlr->mslookup.vty.server.mdns.bind_addr.ip;
+	const char *port_str = argc > 2? argv[2] : NULL;
+	uint16_t port_nr = port_str ? atoi(port_str) : g_hlr->mslookup.vty.server.mdns.bind_addr.port;
 	struct osmo_sockaddr_str addr;
-	if (osmo_sockaddr_str_from_str(&addr, ip_str, atoi(port_str))
+	if (osmo_sockaddr_str_from_str(&addr, ip_str, port_nr)
 	    || !osmo_sockaddr_str_is_nonzero(&addr)) {
-		vty_out(vty, "%% MS Lookup server: Invalid mDNS bind address: %s %s%s",
-			ip_str, port_str, VTY_NEWLINE);
+		vty_out(vty, "%% MS Lookup server: Invalid mDNS bind address: %s %u%s",
+			ip_str, port_nr, VTY_NEWLINE);
 		return CMD_WARNING;
 	}
 
-	dgsm_config_vty.server.dns.multicast_bind_addr = addr;
-	dgsm_config_vty.server.dns.enable = true;
+	g_hlr->mslookup.vty.server.mdns.bind_addr = addr;
+	g_hlr->mslookup.vty.server.mdns.enable = true;
+	dgsm_config_apply();
 	return CMD_SUCCESS;
 }
 
-DEFUN(cfg_mslookup_server_no_dns,
-      cfg_mslookup_server_no_dns_cmd,
-      "no dns",
+DEFUN(cfg_mslookup_server_no_mdns,
+      cfg_mslookup_server_no_mdns_cmd,
+      "no mdns",
       NO_STR "Disable server for DNS/mDNS MS Lookup (do not answer remote requests)\n")
 {
-	dgsm_config_vty.server.dns.enable = false;
+	g_hlr->mslookup.vty.server.mdns.enable = false;
+	dgsm_config_apply();
 	return CMD_SUCCESS;
 }
 
@@ -115,17 +118,17 @@ DEFUN(cfg_mslookup_server_msc,
       "Configure services for individual local MSCs\n"
       "IPA Unit Name of the local MSC to configure\n")
 {
-	const char *unit_name = argv_concat(argv, argc, 0);
-	struct dgsm_msc_config *msc = dgsm_config_msc_get((uint8_t*)unit_name, strlen(unit_name),
-							  true);
+	struct global_title msc_name;
+	struct dgsm_msc_config *msc;
+	global_title_set_str(&msc_name, argv_concat(argv, argc, 0));
+
+	msc = dgsm_config_msc_get(&msc_name, true);
 	if (!msc) {
-		vty_out(vty, "%% Error creating MSC %s%s",
-			osmo_quote_str(unit_name, -1), VTY_NEWLINE);
+		vty_out(vty, "%% Error creating MSC %s%s", global_title_name(&msc_name), VTY_NEWLINE);
 		return CMD_WARNING;
 	}
 	vty->node = MSLOOKUP_SERVER_MSC_NODE;
 	vty->index = msc;
-	printf("%s vty->node = %d\n", __func__, vty->node);
 	return CMD_SUCCESS;
 }
 
@@ -145,13 +148,20 @@ DEFUN(cfg_mslookup_server_msc_service,
 	/* If this command is run on the 'server' node, it produces an empty unit name and serves as wildcard for all
 	 * MSCs. If on a 'server' / 'msc' node, set services only for that MSC Unit Name. */
 	struct dgsm_msc_config *msc = (vty->node == MSLOOKUP_SERVER_MSC_NODE) ? vty->index : NULL;
-	uint8_t *unit_name = msc ? msc->unit_name : NULL;
-	size_t unit_name_len = msc ? msc->unit_name_len : 0;
 	const char *service = argv[0];
 	const char *ip_str = argv[1];
 	const char *port_str = argv[2];
 	struct osmo_sockaddr_str addr;
 
+	/* On the mslookup.server node, set services on the wildcard msc, without a particular name. */
+	if (vty->node == MSLOOKUP_SERVER_NODE)
+		msc = dgsm_config_msc_get(&dgsm_config_msc_wildcard, true);
+
+	if (!msc) {
+		vty_out(vty, "%% Error: no MSC object on this node%s", VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
 	if (osmo_sockaddr_str_from_str(&addr, ip_str, atoi(port_str))
 	    || !osmo_sockaddr_str_is_nonzero(&addr)) {
 		vty_out(vty, "%% MS Lookup server: Invalid address for service %s: %s %s%s",
@@ -159,7 +169,7 @@ DEFUN(cfg_mslookup_server_msc_service,
 		return CMD_WARNING;
 	}
 
-	if (dgsm_config_service_set(unit_name, unit_name_len, service, &addr)) {
+	if (dgsm_config_msc_service_set(msc, service, &addr)) {
 		vty_out(vty, "%% MS Lookup server: Error setting service %s to %s %s%s",
 			service, ip_str, port_str, VTY_NEWLINE);
 		return CMD_WARNING;
@@ -177,11 +187,9 @@ DEFUN(cfg_mslookup_server_msc_no_service,
 	/* If this command is run on the 'server' node, it produces an empty unit name and serves as wildcard for all
 	 * MSCs. If on a 'server' / 'msc' node, set services only for that MSC Unit Name. */
 	struct dgsm_msc_config *msc = (vty->node == MSLOOKUP_SERVER_MSC_NODE) ? vty->index : NULL;
-	uint8_t *unit_name = msc ? msc->unit_name : NULL;
-	size_t unit_name_len = msc ? msc->unit_name_len : 0;
 	const char *service = argv[0];
 
-	if (dgsm_config_service_del(unit_name, unit_name_len, service, NULL)) {
+	if (dgsm_config_msc_service_del(msc, service, NULL)) {
 		vty_out(vty, "%% MS Lookup server: Error removing service %s%s",
 			service, VTY_NEWLINE);
 		return CMD_WARNING;
@@ -197,8 +205,6 @@ DEFUN(cfg_mslookup_server_msc_no_service_addr,
 	/* If this command is run on the 'server' node, it produces an empty unit name and serves as wildcard for all
 	 * MSCs. If on a 'server' / 'msc' node, set services only for that MSC Unit Name. */
 	struct dgsm_msc_config *msc = (vty->node == MSLOOKUP_SERVER_MSC_NODE) ? vty->index : NULL;
-	uint8_t *unit_name = msc ? msc->unit_name : NULL;
-	size_t unit_name_len = msc ? msc->unit_name_len : 0;
 	const char *service = argv[0];
 	const char *ip_str = argv[1];
 	const char *port_str = argv[2];
@@ -211,7 +217,7 @@ DEFUN(cfg_mslookup_server_msc_no_service_addr,
 		return CMD_WARNING;
 	}
 
-	if (dgsm_config_service_del(unit_name, unit_name_len, service, &addr)) {
+	if (dgsm_config_service_del(&msc->name, service, &addr)) {
 		vty_out(vty, "%% MS Lookup server: Error removing service %s to %s %s%s",
 			service, ip_str, port_str, VTY_NEWLINE);
 		return CMD_WARNING;
@@ -231,7 +237,8 @@ DEFUN(cfg_mslookup_client,
       "Enable and configure Distributed GSM / multicast MS Lookup client")
 {
 	vty->node = MSLOOKUP_CLIENT_NODE;
-	dgsm_config.client.enable = true;
+	g_hlr->mslookup.vty.client.enable = true;
+	dgsm_config_apply();
 	return CMD_SUCCESS;
 }
 
@@ -240,7 +247,58 @@ DEFUN(cfg_mslookup_no_client,
       "no client",
       NO_STR "Disable Distributed GSM / multicast MS Lookup client")
 {
-	dgsm_config.client.enable = false;
+	g_hlr->mslookup.vty.client.enable = false;
+	dgsm_config_apply();
+	return CMD_SUCCESS;
+}
+
+#define MDNS_TO_STR MDNS_STR "Configure to which multicast address mDNS MS Lookup requests are sent\n"
+
+DEFUN(cfg_mslookup_client_timeout,
+      cfg_mslookup_client_timeout_cmd,
+      "timeout <1-100000>",
+      "How long should the mslookup client wait for remote responses before evaluating received results\n"
+      "timeout in milliseconds\n")
+{
+	uint32_t val = atol(argv[0]);
+	g_hlr->mslookup.vty.client.timeout.tv_sec = val / 1000;
+	g_hlr->mslookup.vty.client.timeout.tv_usec = (val % 1000) * 1000;
+	return CMD_SUCCESS;
+}
+
+#define EXIT_HINT() \
+	if (vty->type != VTY_FILE) \
+		vty_out(vty, "%% 'exit' this node to apply changes%s", VTY_NEWLINE)
+
+DEFUN(cfg_mslookup_client_mdns,
+      cfg_mslookup_client_mdns_cmd,
+      "mdns [to] [IP] [<1-65535>]",
+      MDNS_STR "Configure multicast address to send mDNS mslookup requests to\n" IP46_STR PORT_STR)
+{
+	const char *ip_str = argc > 1? argv[1] : g_hlr->mslookup.vty.client.mdns.query_addr.ip;
+	const char *port_str = argc > 2? argv[2] : NULL;
+	uint16_t port_nr = port_str ? atoi(port_str) : g_hlr->mslookup.vty.client.mdns.query_addr.port;
+	struct osmo_sockaddr_str addr;
+	if (osmo_sockaddr_str_from_str(&addr, ip_str, port_nr)
+	    || !osmo_sockaddr_str_is_nonzero(&addr)) {
+		vty_out(vty, "%% MS Lookup client: Invalid mDNS target address: %s %u%s",
+			ip_str, port_nr, VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	g_hlr->mslookup.vty.client.mdns.query_addr = addr;
+	g_hlr->mslookup.vty.client.mdns.enable = true;
+	dgsm_config_apply();
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mslookup_client_no_mdns,
+      cfg_mslookup_client_no_mdns_cmd,
+      "no mdns",
+      NO_STR "Disable mDNS client, do not query remote services by mDNS\n")
+{
+	g_hlr->mslookup.vty.client.mdns.enable = false;
+	dgsm_config_apply();
 	return CMD_SUCCESS;
 }
 
@@ -269,14 +327,14 @@ void dgsm_vty_init()
 	install_element(CONFIG_NODE, &cfg_mslookup_cmd);
 
 	install_node(&mslookup_node, config_write_mslookup);
-	install_element(MSLOOKUP_NODE, &cfg_mslookup_dns_cmd);
-	install_element(MSLOOKUP_NODE, &cfg_mslookup_no_dns_cmd);
+	install_element(MSLOOKUP_NODE, &cfg_mslookup_mdns_cmd);
+	install_element(MSLOOKUP_NODE, &cfg_mslookup_no_mdns_cmd);
 	install_element(MSLOOKUP_NODE, &cfg_mslookup_server_cmd);
 	install_element(MSLOOKUP_NODE, &cfg_mslookup_no_server_cmd);
 
 	install_node(&mslookup_server_node, config_write_mslookup_server);
-	install_element(MSLOOKUP_SERVER_NODE, &cfg_mslookup_server_dns_bind_multicast_cmd);
-	install_element(MSLOOKUP_SERVER_NODE, &cfg_mslookup_server_no_dns_cmd);
+	install_element(MSLOOKUP_SERVER_NODE, &cfg_mslookup_server_mdns_bind_cmd);
+	install_element(MSLOOKUP_SERVER_NODE, &cfg_mslookup_server_no_mdns_cmd);
 	install_element(MSLOOKUP_SERVER_NODE, &cfg_mslookup_server_msc_service_cmd);
 	install_element(MSLOOKUP_SERVER_NODE, &cfg_mslookup_server_msc_no_service_cmd);
 	install_element(MSLOOKUP_SERVER_NODE, &cfg_mslookup_server_msc_no_service_addr_cmd);
@@ -290,18 +348,12 @@ void dgsm_vty_init()
 	install_element(MSLOOKUP_NODE, &cfg_mslookup_client_cmd);
 	install_element(MSLOOKUP_NODE, &cfg_mslookup_no_client_cmd);
 	install_node(&mslookup_client_node, config_write_mslookup_client);
+	install_element(MSLOOKUP_CLIENT_NODE, &cfg_mslookup_client_timeout_cmd);
+	install_element(MSLOOKUP_CLIENT_NODE, &cfg_mslookup_client_mdns_cmd);
+	install_element(MSLOOKUP_CLIENT_NODE, &cfg_mslookup_client_no_mdns_cmd);
 
 }
 
 void dgsm_vty_go_parent_action(struct vty *vty)
 {
-	/* Exiting 'mslookup' VTY node, apply new config. */
-	switch (vty->node) {
-	case MSLOOKUP_SERVER_NODE:
-		dgsm_dns_server_config_apply();
-		break;
-	case MSLOOKUP_CLIENT_NODE:
-		dgsm_dns_client_config_apply();
-		break;
-	}
 }
diff --git a/src/global_title.c b/src/global_title.c
index 9df45d6..10fbb11 100644
--- a/src/global_title.c
+++ b/src/global_title.c
@@ -16,6 +16,11 @@ int global_title_set(struct global_title *gt, const uint8_t *val, size_t len)
 	return 0;
 }
 
+int global_title_set_str(struct global_title *gt, const char *str)
+{
+	return global_title_set(gt, (const uint8_t*)str, str ? strlen(str)+1 : 0);
+}
+
 int global_title_cmp(const struct global_title *a, const struct global_title *b)
 {
 	int cmp;
diff --git a/src/global_title.h b/src/global_title.h
index 017c7fe..54e23a3 100644
--- a/src/global_title.h
+++ b/src/global_title.h
@@ -12,5 +12,6 @@ struct global_title {
 };
 
 int global_title_set(struct global_title *gt, const uint8_t *val, size_t len);
+int global_title_set_str(struct global_title *gt, const char *str);
 int global_title_cmp(const struct global_title *a, const struct global_title *b);
 const char *global_title_name(const struct global_title *gt);
diff --git a/src/hlr.c b/src/hlr.c
index df72f04..7b24017 100644
--- a/src/hlr.c
+++ b/src/hlr.c
@@ -49,6 +49,7 @@
 #include "hlr_vty.h"
 #include "hlr_ussd.h"
 #include "dgsm.h"
+#include "proxy.h"
 
 struct hlr *g_hlr;
 static void *hlr_ctx = NULL;
@@ -429,14 +430,14 @@ static int rx_purge_ms_req(struct osmo_gsup_conn *conn,
 	bool is_ps = false;
 	int rc;
 
-	LOGP(DAUC, LOGL_INFO, "%s: Purge MS (%s)\n", gsup->imsi,
-		is_ps ? "PS" : "CS");
-
 	memcpy(gsup_reply.imsi, gsup->imsi, sizeof(gsup_reply.imsi));
 
 	if (gsup->cn_domain == OSMO_GSUP_CN_DOMAIN_PS)
 		is_ps = true;
 
+	LOGP(DAUC, LOGL_INFO, "%s: Purge MS (%s)\n", gsup->imsi,
+		is_ps ? "PS" : "CS");
+
 	/* FIXME: check if the VLR that sends the purge is the same that
 	 * we have on record. Only update if yes */
 
@@ -836,6 +837,9 @@ int main(int argc, char **argv)
 	/* Init default (call independent) SS session guard timeout value */
 	g_hlr->ncss_guard_timeout = NCSS_GUARD_TIMEOUT_DEFAULT;
 
+	g_hlr->gsup_proxy.cs = proxy_init(g_hlr);
+	g_hlr->gsup_proxy.ps = proxy_init(g_hlr);
+
 	rc = osmo_init_logging2(hlr_ctx, &hlr_log_info);
 	if (rc < 0) {
 		fprintf(stderr, "Error initializing logging\n");
@@ -903,6 +907,8 @@ int main(int argc, char **argv)
 	g_hlr->ctrl_bind_addr = ctrl_vty_get_bind_addr();
 	g_hlr->ctrl = hlr_controlif_setup(g_hlr);
 
+	dgsm_start(hlr_ctx);
+
 	osmo_init_ignore_signals();
 	signal(SIGINT, &signal_hdlr);
 	signal(SIGTERM, &signal_hdlr);
diff --git a/src/hlr.h b/src/hlr.h
index 9bf3786..52356af 100644
--- a/src/hlr.h
+++ b/src/hlr.h
@@ -25,6 +25,7 @@
 #include <stdbool.h>
 #include <osmocom/core/linuxlist.h>
 #include <osmocom/gsm/ipa.h>
+#include "dgsm.h"
 
 #define HLR_DEFAULT_DB_FILE_PATH "hlr.db"
 
@@ -66,19 +67,24 @@ struct hlr {
 	unsigned int subscr_create_on_demand_rand_msisdn_len;
 
 	struct {
+		bool allow_startup;
+		struct dgsm_config vty;
+
 		struct {
-			struct osmo_mslookup_server_dns *dns;
+			struct osmo_mslookup_server_mdns *mdns;
+			uint32_t max_age;
 		} server;
 
 		struct {
 			struct osmo_mslookup_client *client;
-
-			struct osmo_mslookup_client_method *dns;
+			struct osmo_mslookup_client_method *mdns;
 		} client;
 	} mslookup;
 
 	struct {
 		struct ipaccess_unit gsup_client_name;
+		struct proxy *cs;
+		struct proxy *ps;
 	} gsup_proxy;
 };
 
diff --git a/src/mslookup_server.c b/src/mslookup_server.c
index e2f3b75..b426417 100644
--- a/src/mslookup_server.c
+++ b/src/mslookup_server.c
@@ -6,37 +6,32 @@
 #include "db.h"
 #include "dgsm.h"
 #include "mslookup_server.h"
+#include "proxy.h"
 
 static const struct osmo_mslookup_result not_found = {
-		.ip_v4.rc = OSMO_MSLOOKUP_RC_NOT_FOUND,
-		.ip_v6.rc = OSMO_MSLOOKUP_RC_NOT_FOUND,
+		.rc = OSMO_MSLOOKUP_RC_NOT_FOUND,
 	};
 
-static void set_result(struct osmo_mslookup_result_part *result,
-		       const struct osmo_sockaddr_str *addr,
+static void set_result(struct osmo_mslookup_result *result,
+		       const struct dgsm_service_host *service_host,
 		       uint32_t age)
 {
-	if (!osmo_sockaddr_str_is_nonzero(addr)) {
-		result->rc = OSMO_MSLOOKUP_RC_NOT_FOUND;
+	if (!osmo_sockaddr_str_is_nonzero(&service_host->host_v4)
+	    && !osmo_sockaddr_str_is_nonzero(&service_host->host_v6)) {
+		*result = not_found;
 		return;
 	}
 	result->rc = OSMO_MSLOOKUP_RC_OK;
-	result->host = *addr;
+	result->host_v4 = service_host->host_v4;
+	result->host_v6 = service_host->host_v6;
 	result->age = age;
 }
 
-static void set_results(struct osmo_mslookup_result *result,
-			const struct dgsm_service_addr *service_addr,
-			uint32_t age)
+/* A remote entity is asking us whether we are the home HLR of the given subscriber. */
+static void mslookup_server_rx_hlr_gsup(const struct osmo_mslookup_query *query,
+					struct osmo_mslookup_result *result)
 {
-	set_result(&result->ip_v4, &service_addr->addr_v4, age);
-	set_result(&result->ip_v6, &service_addr->addr_v6, age);
-}
-
-void mslookup_server_rx_hlr_gsup(const struct osmo_mslookup_query *query,
-				 struct osmo_mslookup_result *result)
-{
-	struct dgsm_service_addr *addr;
+	struct dgsm_service_host *host;
 	int rc;
 	switch (query->id.type) {
 	case OSMO_MSLOOKUP_ID_IMSI:
@@ -62,41 +57,203 @@ void mslookup_server_rx_hlr_gsup(const struct osmo_mslookup_query *query,
 	     osmo_mslookup_result_name_c(OTC_SELECT, query, NULL));
 
 	/* Find a HLR/GSUP service set for the server (no MSC unit name) */
-	addr = dgsm_config_service_get(NULL, 0, OSMO_MSLOOKUP_SERVICE_HLR_GSUP);
-	if (!addr) {
-		LOGP(DDGSM, LOGL_ERROR,
-		     "Subscriber found, but no service '" OSMO_MSLOOKUP_SERVICE_HLR_GSUP "' configured,"
-		     " cannot service HLR lookup request\n");
-		*result = not_found;
+	host = dgsm_config_service_get(&dgsm_config_msc_wildcard, OSMO_MSLOOKUP_SERVICE_HLR_GSUP);
+	if (!host) {
+		struct dgsm_service_host gsup_bind = {};
+		/* Try to use the locally configured GSUP bind address */
+		osmo_sockaddr_str_from_str(&gsup_bind.host_v4, g_hlr->gsup_bind_addr, OSMO_GSUP_PORT);
+		if (gsup_bind.host_v4.af == AF_INET6) {
+			gsup_bind.host_v6 = gsup_bind.host_v4;
+			gsup_bind.host_v4 = (struct osmo_sockaddr_str){};
+		}
+		set_result(result, &gsup_bind, 0);
+		if (result->rc != OSMO_MSLOOKUP_RC_OK) {
+			LOGP(DDGSM, LOGL_ERROR,
+			     "Subscriber found, but no service '" OSMO_MSLOOKUP_SERVICE_HLR_GSUP "' configured,"
+			     " and cannot use configured GSUP bind address %s in mslookup response."
+			     " Cannot service HLR lookup request\n",
+			     osmo_quote_str(g_hlr->gsup_bind_addr, -1));
+		}
 		return;
 	}
 
-	set_results(result, addr, 0);
+	set_result(result, host, 0);
+	if (result->rc != OSMO_MSLOOKUP_RC_OK) {
+		LOGP(DDGSM, LOGL_ERROR,
+		     "Subscriber found, but error in service '" OSMO_MSLOOKUP_SERVICE_HLR_GSUP "' config:"
+		     " v4: " OSMO_SOCKADDR_STR_FMT "  v6: " OSMO_SOCKADDR_STR_FMT "\n",
+		     OSMO_SOCKADDR_STR_FMT_ARGS(&host->host_v4),
+		     OSMO_SOCKADDR_STR_FMT_ARGS(&host->host_v6));
+	}
+}
+
+/* Look in the local HLR record: If the subscriber is "at home" in this HLR and is also currently located at a local
+ * MSC, we will find a valid location updating with vlr_number, and no vlr_via_proxy entry. */
+static bool subscriber_has_done_lu_here_hlr(const struct osmo_mslookup_query *query,
+					    uint32_t *lu_age,
+					    struct global_title *local_msc_name)
+{
+	struct hlr_subscriber subscr;
+	struct timeval age_tv;
+	int rc;
+	uint32_t age;
+
+	switch (query->id.type) {
+	case OSMO_MSLOOKUP_ID_IMSI:
+		rc = db_subscr_get_by_imsi(g_hlr->dbc, query->id.imsi, &subscr);
+		break;
+	case OSMO_MSLOOKUP_ID_MSISDN:
+		rc = db_subscr_get_by_msisdn(g_hlr->dbc, query->id.msisdn, &subscr);
+		break;
+	default:
+		LOGP(DDGSM, LOGL_ERROR, "Unknown mslookup ID type: %d\n", query->id.type);
+		return false;
+	}
+
+	if (rc) {
+		LOGP(DDGSM, LOGL_DEBUG, "%s: Does not exist in local HLR\n",
+		     osmo_mslookup_result_name_c(OTC_SELECT, query, NULL));
+		return false;
+	}
+
+	if (!subscr.vlr_number[0]) {
+		LOGP(DDGSM, LOGL_DEBUG, "%s: Not attached\n",
+		     osmo_mslookup_result_name_c(OTC_SELECT, query, NULL));
+	}
+
+	if (subscr.vlr_via_proxy.len) {
+		/* The MSC is behind a proxy, the subscriber is not attached to a local MSC but a remote one. That
+		 * remote proxy should instead respond to the service lookup request. */
+		LOGP(DDGSM, LOGL_DEBUG, "%s: last attach is not at local MSC, but via proxy %s\n",
+		     osmo_mslookup_result_name_c(OTC_SELECT, query, NULL),
+		     global_title_name(&subscr.vlr_via_proxy));
+		return false;
+	}
+
+	age_tv = (struct timeval){ .tv_sec = subscr.last_lu_seen };
+	age = timestamp_age(&age_tv);
+
+	if (age > g_hlr->mslookup.server.max_age) {
+		LOGP(DDGSM, LOGL_ERROR, "%s: last attach was here, but too long ago: %us\n",
+		     osmo_mslookup_result_name_c(OTC_SELECT, query, NULL),
+		     age);
+		return false;
+	}
+
+	*lu_age = age;
+	global_title_set_str(local_msc_name, subscr.vlr_number);
+	LOGP(DDGSM, LOGL_DEBUG, "%s: attached %u seconds ago at local MSC %s\n",
+	     osmo_mslookup_result_name_c(OTC_SELECT, query, NULL),
+	     age, global_title_name(local_msc_name));
+
+	return true;
 }
 
-/* Determine whether the subscriber with the given ID has routed a Location Updating via this HLR as first hop -- either
- * entirely here, or here first but proxying to a remote HLR. Do not return a match if the LU was registered here
- * (because this is the home HLR) but the LU was routed via a closer HLR first.
- * A proxy adds source_name IEs to forwarded GSUP requests that indicates the MSC where the subscriber is attached.
- * So a) if the LU that was received at the home HLR contained a source_name, we know that the LU happened at a remote
- * MSC. b) The source_name is stored as the vlr_number; hence if that vlr_number is not known locally, we know the LU
- * happened at a remote MSC. (at the time of writing it is not yet clear whether we'll use a or b).
+
+/* Determine whether the subscriber with the given ID has routed a Location Updating via this HLR as first hop. Return
+ * true if it is attached at a local MSC, and we are serving as proxy for a remote home HLR.
  */
-bool subscriber_has_done_location_updating_here(const struct osmo_mslookup_id *id,
-						uint32_t *lu_age,
-						const uint8_t **lu_msc_unit_name,
-						size_t *lu_msc_unit_name_len)
+static bool subscriber_has_done_lu_here_proxy(const struct osmo_mslookup_query *query,
+					      uint32_t *lu_age,
+					      struct global_title *local_msc_name)
+{
+	const struct proxy_subscr *subscr;
+	uint32_t age;
+
+	/* See the local HLR record. If the subscriber is "at home" in this HLR and is also currently located here, we
+	 * will find a valid location updating and no vlr_via_proxy entry. */
+	switch (query->id.type) {
+	case OSMO_MSLOOKUP_ID_IMSI:
+		subscr = proxy_subscr_get_by_imsi(g_hlr->gsup_proxy.cs, query->id.imsi);
+		break;
+	case OSMO_MSLOOKUP_ID_MSISDN:
+		subscr = proxy_subscr_get_by_msisdn(g_hlr->gsup_proxy.cs, query->id.msisdn);
+		break;
+	default:
+		LOGP(DDGSM, LOGL_ERROR, "Unknown mslookup ID type: %d\n", query->id.type);
+		return false;
+	}
+
+	if (!subscr) {
+		LOGP(DDGSM, LOGL_DEBUG, "%s: does not exist in GSUP proxy\n",
+		     osmo_mslookup_result_name_c(OTC_SELECT, query, NULL));
+		return false;
+	}
+
+	age = timestamp_age(&subscr->last_lu);
+
+	if (age > g_hlr->mslookup.server.max_age) {
+		LOGP(DDGSM, LOGL_ERROR, "%s: last attach was here (proxy), but too long ago: %us\n",
+		     osmo_mslookup_result_name_c(OTC_SELECT, query, NULL),
+		     age);
+		return false;
+	}
+
+	*lu_age = age;
+	*local_msc_name = subscr->vlr_name;
+	LOGP(DDGSM, LOGL_DEBUG, "%s: attached %u seconds ago at local MSC %s; proxying for remote HLR "
+	     OSMO_SOCKADDR_STR_FMT "\n",
+	     osmo_mslookup_result_name_c(OTC_SELECT, query, NULL),
+	     age, global_title_name(local_msc_name),
+	     OSMO_SOCKADDR_STR_FMT_ARGS(&subscr->remote_hlr));
+
+	return true;
+}
+
+static bool subscriber_has_done_lu_here(const struct osmo_mslookup_query *query,
+					uint32_t *lu_age_p,
+					struct global_title *local_msc_name)
 {
-	return false;
+	uint32_t lu_age = 0;
+	struct global_title msc_name = {};
+	uint32_t proxy_lu_age = 0;
+	struct global_title proxy_msc_name = {};
+
+	/* First ask the local HLR db, but if the local proxy record indicates a more recent LU, use that instead.
+	 * For all usual cases, only one of these will reflect a LU, even if a subscriber had more than one home HLR:
+	 *   - if the subscriber is known here, we will never proxy.
+	 *   - if the subscriber is not known here, this local HLR db will never record a LU.
+	 * However, if a subscriber was being proxied to a remote home HLR, and if then the subscriber was also added to
+	 * the local HLR database, there might occur a situation where both reflect a LU. So, to be safe against all
+	 * situations, compare the two entries.
+	 */
+	if (!subscriber_has_done_lu_here_hlr(query, &lu_age, &msc_name))
+		lu_age = 0;
+	if (!subscriber_has_done_lu_here_proxy(query, &proxy_lu_age, &proxy_msc_name))
+		proxy_lu_age = 0;
+	if (lu_age && proxy_lu_age) {
+		LOGP(DDGSM, LOGL_DEBUG,
+		     "%s: a LU is on record both in the local HLR (age %us) and the GSUP proxy (age %us)\n",
+		     osmo_mslookup_result_name_c(OTC_SELECT, query, NULL),
+		     lu_age, proxy_lu_age);
+	}
+	/* If proxy has a younger lu, replace. */
+	if (proxy_lu_age && (!lu_age || (proxy_lu_age < lu_age))) {
+		lu_age = proxy_lu_age;
+		msc_name = proxy_msc_name;
+	}
+
+	if (!lu_age || !msc_name.len) {
+		LOGP(DDGSM, LOGL_DEBUG, "%s: not attached here\n",
+		     osmo_mslookup_result_name_c(OTC_SELECT, query, NULL));
+		return false;
+	}
+
+	LOGP(DDGSM, LOGL_DEBUG, "%s: attached here, at MSC %s\n",
+	     osmo_mslookup_result_name_c(OTC_SELECT, query, NULL),
+	     global_title_name(&msc_name));
+	*lu_age_p = lu_age;
+	*local_msc_name = msc_name;
+	return true;
 }
 
-void mslookup_server_rx(const struct osmo_mslookup_query *query,
-			struct osmo_mslookup_result *result)
+/* A remote entity is asking us whether we are providing the given service for the given subscriber. */
+void osmo_mslookup_server_rx(const struct osmo_mslookup_query *query,
+			     struct osmo_mslookup_result *result)
 {
-	const uint8_t *msc_unit_name;
-	size_t msc_unit_name_len;
-	const struct dgsm_service_addr *service_addr;
+	const struct dgsm_service_host *service_host;
 	uint32_t age;
+	struct global_title msc_name;
 
 	/* A request for a home HLR: answer exactly if this is the subscriber's home HLR, i.e. the IMSI is listed in the
 	 * HLR database. */
@@ -106,28 +263,28 @@ void mslookup_server_rx(const struct osmo_mslookup_query *query,
 	/* All other service types: answer when the subscriber has done a LU that is either listed in the local HLR or
 	 * in the GSUP proxy database: i.e. if the subscriber has done a Location Updating at an MSC belonging to this
 	 * HLR. Respond with whichever services are configured in the osmo-hlr.cfg. */
-	if (!subscriber_has_done_location_updating_here(&query->id, &age, &msc_unit_name, &msc_unit_name_len)) {
+	if (!subscriber_has_done_lu_here(query, &age, &msc_name)) {
 		*result = not_found;
 		return;
 	}
 
 	/* We've detected a LU here. The MSC where the LU happened is stored in msc_unit_name, and the LU age is stored
 	 * in 'age'. Figure out the address configured for that MSC and service name. */
-	service_addr = dgsm_config_service_get(msc_unit_name, msc_unit_name_len, query->service);
-	if (!service_addr) {
+	service_host = dgsm_config_service_get(&msc_name, query->service);
+
+	if (!service_host) {
+		/* Find such service set globally (no MSC unit name) */
+		service_host = dgsm_config_service_get(&dgsm_config_msc_wildcard, query->service);
+	}
+
+	if (!service_host) {
+		LOGP(DDGSM, LOGL_ERROR,
+		     "%s: subscriber found, but no service %s configured, cannot service lookup request\n",
+		     osmo_mslookup_result_name_c(OTC_SELECT, query, NULL),
+		     osmo_quote_str_c(OTC_SELECT, query->service, -1));
 		*result = not_found;
 		return;
 	}
 
-	set_results(result, service_addr, age);
-}
-
-struct osmo_mslookup_server_dns *osmo_mslookup_server_dns_start(const struct osmo_sockaddr_str *multicast_bind_addr)
-{
-	return NULL;
+	set_result(result, service_host, age);
 }
-
-void osmo_mslookup_server_dns_stop(struct osmo_mslookup_server_dns *server)
-{
-}
-
diff --git a/src/mslookup_server.h b/src/mslookup_server.h
index 2b8d494..c61792a 100644
--- a/src/mslookup_server.h
+++ b/src/mslookup_server.h
@@ -1,9 +1,7 @@
 #pragma once
 
-struct osmo_mslookup_server_dns {
-	bool running;
-	struct osmo_sockaddr_str multicast_bind_addr;
-};
+struct osmo_mslookup_query;
+struct osmo_mslookup_result;
 
-struct osmo_mslookup_server_dns *osmo_mslookup_server_dns_start(const struct osmo_sockaddr_str *multicast_bind_addr);
-void osmo_mslookup_server_dns_stop(struct osmo_mslookup_server_dns *server);
+void osmo_mslookup_server_rx(const struct osmo_mslookup_query *query,
+			     struct osmo_mslookup_result *result);
diff --git a/src/mslookup_server_mdns.c b/src/mslookup_server_mdns.c
new file mode 100644
index 0000000..982ba15
--- /dev/null
+++ b/src/mslookup_server_mdns.c
@@ -0,0 +1,163 @@
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <osmocom/mslookup/mslookup.h>
+#include <osmocom/mslookup/mdns.h>
+#include "logging.h"
+#include "mslookup_server.h"
+#include "mslookup_server_mdns.h"
+
+static void osmo_mslookup_server_mdns_tx(struct osmo_mslookup_server_mdns *server,
+					 const struct osmo_mdns_request *req,
+					 const struct osmo_mslookup_query *query,
+					 const struct osmo_mslookup_result *result)
+{
+	const char *errmsg = NULL;
+	struct msgb *msg;
+	struct osmo_mdns_answer ans;
+	struct osmo_mdns_record *rec_age;
+	struct osmo_mdns_record rec_ip_v4 = {};
+	struct osmo_mdns_record *rec_ip_v4_port;
+	struct osmo_mdns_record rec_ip_v6 = {};
+	struct osmo_mdns_record *rec_ip_v6_port;
+	uint32_t ip_v4;
+	struct in6_addr ip_v6;
+
+	void *ctx = talloc_named_const(server, 0, __func__);
+
+	osmo_mdns_answer_init(&ans);
+	ans.id = req->id;
+	ans.domain = req->domain;
+
+	rec_age = dns_encode_txt_record(ctx, "age", "%u", result->age);
+	llist_add(&rec_age->list, &ans.records);
+
+	if (osmo_sockaddr_str_is_nonzero(&result->host_v4)) {
+		if (osmo_sockaddr_str_to_32n(&result->host_v4, &ip_v4)) {
+			errmsg = "Error encoding IPv4 address";
+			goto clean_and_exit;
+		}
+		rec_ip_v4.type = OSMO_MSLOOKUP_MDNS_RECORD_TYPE_A;
+		rec_ip_v4.data = (void*)&ip_v4;
+		rec_ip_v4.length = sizeof(ip_v4);
+		llist_add(&rec_ip_v4.list, &ans.records);
+
+		rec_ip_v4_port = dns_encode_txt_record(ctx, "port", "%u", result->host_v4.port);
+		if (!rec_ip_v4_port) {
+			errmsg = "Error encoding IPv4 port";
+			goto clean_and_exit;
+		}
+		llist_add(&rec_ip_v4_port->list, &ans.records);
+	}
+
+	if (osmo_sockaddr_str_is_nonzero(&result->host_v6)) {
+		if (osmo_sockaddr_str_to_in6_addr(&result->host_v6, &ip_v6)) {
+			errmsg = "Error encoding IPv6 address";
+			goto clean_and_exit;
+		}
+
+		rec_ip_v6.type = OSMO_MSLOOKUP_MDNS_RECORD_TYPE_AAAA;
+		rec_ip_v6.data = (void*)&ip_v6;
+		rec_ip_v6.length = sizeof(ip_v6);
+		llist_add(&rec_ip_v6.list, &ans.records);
+
+		rec_ip_v6_port = dns_encode_txt_record(ctx, "port", "%u", result->host_v6.port);
+		if (!rec_ip_v6_port) {
+			errmsg = "Error encoding IPv6 port";
+			goto clean_and_exit;
+		}
+		llist_add(&rec_ip_v6_port->list, &ans.records);
+	}
+
+	msg = msgb_alloc(1024, __func__);
+	if (dns_encode_answer(ctx, msg, &ans)) {
+		errmsg = "Error encoding DNS answer packet";
+		goto clean_and_exit;
+	}
+
+	if (osmo_mdns_sock_send(server->sock, msg))
+		errmsg = "Error sending DNS answer";
+
+clean_and_exit:
+	if (errmsg)
+		LOGP(DDGSM, LOGL_ERROR, "%s: DNS: %s\n", osmo_mslookup_result_name_c(ctx, query, result), errmsg);
+	talloc_free(ctx);
+}
+
+static void osmo_mslookup_server_mdns_handle_request(struct osmo_mslookup_server_mdns *server,
+						     const struct osmo_mdns_request *req)
+{
+	struct osmo_mslookup_query query;
+	struct osmo_mslookup_result result;
+
+	if (osmo_mslookup_query_from_domain_str(&query, req->domain)) {
+		LOGP(DDGSM, LOGL_ERROR, "mDNS mslookup server: unable to parse request domain string: %s\n",
+		     osmo_quote_str_c(OTC_SELECT, req->domain, -1));
+		return;
+	}
+
+	osmo_mslookup_server_rx(&query, &result);
+	/* Error logging already happens in osmo_mslookup_server_rx() */
+	if (result.rc != OSMO_MSLOOKUP_RC_OK)
+		return;
+
+	osmo_mslookup_server_mdns_tx(server, req, &query, &result);
+}
+
+static int osmo_mslookup_server_mdns_rx(struct osmo_fd *osmo_fd, unsigned int what)
+{
+	struct osmo_mslookup_server_mdns *server = osmo_fd->data;
+	struct osmo_mdns_request *req;
+	int n;
+	uint8_t buffer[1024];
+	void *ctx;
+
+	/* Parse the message and print it */
+	n = read(osmo_fd->fd, buffer, sizeof(buffer));
+	if (n < 0)
+		return n;
+
+	ctx = talloc_named_const(server, 0, __func__);
+	req = dns_decode_request(ctx, buffer, n);
+	if (!req) {
+		LOGP(DDGSM, LOGL_DEBUG, "mDNS rx: ignoring: not a request\n");
+		talloc_free(ctx);
+		return -1;
+	}
+
+	LOGP(DDGSM, LOGL_DEBUG, "mDNS rx request: %s\n", osmo_quote_str_c(OTC_SELECT, req->domain, -1));
+	osmo_mslookup_server_mdns_handle_request(server, req);
+	talloc_free(ctx);
+	return n;
+}
+
+struct osmo_mslookup_server_mdns *osmo_mslookup_server_mdns_start(void *ctx, const struct osmo_sockaddr_str *bind_addr)
+{
+	struct osmo_mslookup_server_mdns *server = talloc_zero(ctx, struct osmo_mslookup_server_mdns);
+	OSMO_ASSERT(server);
+	*server = (struct osmo_mslookup_server_mdns){
+		.bind_addr = *bind_addr,
+	};
+
+	server->sock = osmo_mdns_sock_init(server,
+					   bind_addr->ip, bind_addr->port, true,
+					   osmo_mslookup_server_mdns_rx,
+					   server, 0);
+	if (!server->sock) {
+		LOGP(DDGSM, LOGL_ERROR,
+		     "mslookup mDNS server: error initializing multicast bind on " OSMO_SOCKADDR_STR_FMT "\n",
+		     OSMO_SOCKADDR_STR_FMT_ARGS(bind_addr));
+		talloc_free(server);
+		return NULL;
+	}
+
+	return server;
+}
+
+void osmo_mslookup_server_mdns_stop(struct osmo_mslookup_server_mdns *server)
+{
+	if (!server)
+		return;
+	osmo_mdns_sock_cleanup(server->sock);
+	talloc_free(server);
+}
diff --git a/src/mslookup_server_mdns.h b/src/mslookup_server_mdns.h
new file mode 100644
index 0000000..8d4d4fc
--- /dev/null
+++ b/src/mslookup_server_mdns.h
@@ -0,0 +1,14 @@
+#pragma once
+
+#include <stdbool.h>
+#include <osmocom/core/sockaddr_str.h>
+#include <osmocom/mslookup/mdns_sock.h>
+
+struct osmo_mslookup_server_mdns {
+	struct osmo_mslookup_server *mslookup;
+	struct osmo_sockaddr_str bind_addr;
+	struct osmo_mdns_sock *sock;
+};
+
+struct osmo_mslookup_server_mdns *osmo_mslookup_server_mdns_start(void *ctx, const struct osmo_sockaddr_str *bind_addr);
+void osmo_mslookup_server_mdns_stop(struct osmo_mslookup_server_mdns *server);
diff --git a/src/proxy.c b/src/proxy.c
index 7bcd080..a93c004 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -6,6 +6,7 @@
 
 #include <osmocom/core/timer.h>
 
+#include "logging.h"
 #include "proxy.h"
 
 /* Why have a separate struct to add an llist_head entry?
@@ -17,14 +18,6 @@ struct proxy_subscr_listentry {
 	struct proxy_subscr data;
 };
 
-static LLIST_HEAD(proxy_subscr_list);
-static void *proxy_ctx = NULL;
-
-/* How long to keep proxy entries without a refresh, in seconds. */
-static time_t proxy_fresh_time = 60 * 60;
-static time_t proxy_fresh_check_period = 60;
-static struct osmo_timer_list proxy_cleanup_timer;
-
 /* Central implementation to set a timestamp to the current time, in case we want to modify this in the future. */
 void timestamp_update(struct timeval *tv)
 {
@@ -47,31 +40,56 @@ static bool proxy_subscr_matches_imsi(const struct proxy_subscr *proxy_subscr, c
 	return strcmp(proxy_subscr->imsi, imsi) == 0;
 }
 
-static struct proxy_subscr_listentry *_proxy_get(const char *imsi)
+static bool proxy_subscr_matches_msisdn(const struct proxy_subscr *proxy_subscr, const char *msisdn)
+{
+	if (!proxy_subscr || !msisdn)
+		return false;
+	return strcmp(proxy_subscr->msisdn, msisdn) == 0;
+}
+
+static struct proxy_subscr_listentry *_proxy_get_by_imsi(struct proxy *proxy, const char *imsi)
 {
 	struct proxy_subscr_listentry *e;
-	llist_for_each_entry(e, &proxy_subscr_list, entry) {
+	llist_for_each_entry(e, &proxy->subscr_list, entry) {
 		if (proxy_subscr_matches_imsi(&e->data, imsi))
 			return e;
 	}
 	return NULL;
 }
 
-const struct proxy_subscr *proxy_subscr_get(const char *imsi)
+static struct proxy_subscr_listentry *_proxy_get_by_msisdn(struct proxy *proxy, const char *msisdn)
+{
+	struct proxy_subscr_listentry *e;
+	llist_for_each_entry(e, &proxy->subscr_list, entry) {
+		if (proxy_subscr_matches_msisdn(&e->data, msisdn))
+			return e;
+	}
+	return NULL;
+}
+
+const struct proxy_subscr *proxy_subscr_get_by_imsi(struct proxy *proxy, const char *imsi)
+{
+	struct proxy_subscr_listentry *e = _proxy_get_by_imsi(proxy, imsi);
+	if (!e)
+		return NULL;
+	return &e->data;
+}
+
+const struct proxy_subscr *proxy_subscr_get_by_msisdn(struct proxy *proxy, const char *msisdn)
 {
-	struct proxy_subscr_listentry *e = _proxy_get(imsi);
+	struct proxy_subscr_listentry *e = _proxy_get_by_msisdn(proxy, msisdn);
 	if (!e)
 		return NULL;
 	return &e->data;
 }
 
-int proxy_subscr_update(const struct proxy_subscr *proxy_subscr)
+int proxy_subscr_update(struct proxy *proxy, const struct proxy_subscr *proxy_subscr)
 {
-	struct proxy_subscr_listentry *e = _proxy_get(proxy_subscr->imsi);
+	struct proxy_subscr_listentry *e = _proxy_get_by_imsi(proxy, proxy_subscr->imsi);
 	if (!e) {
 		/* Does not exist yet */
-		e = talloc_zero(proxy_ctx, struct proxy_subscr_listentry);
-		llist_add(&e->entry, &proxy_subscr_list);
+		e = talloc_zero(proxy, struct proxy_subscr_listentry);
+		llist_add(&e->entry, &proxy->subscr_list);
 	}
 	e->data = *proxy_subscr;
 	timestamp_update(&e->last_update);
@@ -84,31 +102,53 @@ int _proxy_subscr_del(struct proxy_subscr_listentry *e)
 	return 0;
 }
 
-int proxy_subscr_del(const char *imsi)
+int proxy_subscr_del(struct proxy *proxy, const char *imsi)
 {
-	struct proxy_subscr_listentry *e = _proxy_get(imsi);
+	struct proxy_subscr_listentry *e = _proxy_get_by_imsi(proxy, imsi);
 	if (!e)
 		return -ENOENT;
 	return _proxy_subscr_del(e);
 }
 
 /* Discard stale proxy entries. */
-static void proxy_cleanup(void *ignore)
+static void proxy_cleanup(void *proxy_v)
 {
+	struct proxy *proxy = proxy_v;
 	struct proxy_subscr_listentry *e, *n;
-	llist_for_each_entry_safe(e, n, &proxy_subscr_list, entry) {
-		if (timestamp_age(&e->last_update) <= proxy_fresh_time)
+	llist_for_each_entry_safe(e, n, &proxy->subscr_list, entry) {
+		if (timestamp_age(&e->last_update) <= proxy->fresh_time)
 			continue;
 		_proxy_subscr_del(e);
 	}
-	osmo_timer_schedule(&proxy_cleanup_timer, proxy_fresh_check_period, 0);
+	if (proxy->gc_period)
+		osmo_timer_schedule(&proxy->gc_timer, proxy->gc_period, 0);
+	else
+		LOGP(DDGSM, LOGL_NOTICE, "Proxy cleanup is switched off (gc_period == 0)\n");
+}
+
+void proxy_set_gc_period(struct proxy *proxy, uint32_t gc_period)
+{
+	proxy->gc_period = gc_period;
+	proxy_cleanup(proxy);
 }
 
-void proxy_init(void *ctx)
+struct proxy *proxy_init(void *ctx)
 {
-	proxy_ctx = ctx;
-	osmo_timer_setup(&proxy_cleanup_timer, &proxy_cleanup, NULL);
+	struct proxy *proxy = talloc_zero(ctx, struct proxy);
+	*proxy = (struct proxy){
+		.fresh_time = 60*60,
+		.gc_period = 60,
+	};
+	INIT_LLIST_HEAD(&proxy->subscr_list);
+
+	osmo_timer_setup(&proxy->gc_timer, proxy_cleanup, proxy);
 	/* Invoke to trigger the first timer schedule */
-	proxy_cleanup(NULL);
+	proxy_set_gc_period(proxy, proxy->gc_period);
+	return proxy;
 }
 
+void proxy_del(struct proxy *proxy)
+{
+	osmo_timer_del(&proxy->gc_timer);
+	talloc_free(proxy);
+}
diff --git a/src/proxy.h b/src/proxy.h
index 91d433d..4d332cf 100644
--- a/src/proxy.h
+++ b/src/proxy.h
@@ -3,16 +3,39 @@
 #include <time.h>
 #include <osmocom/gsm/protocol/gsm_23_003.h>
 #include <osmocom/core/sockaddr_str.h>
+#include "global_title.h"
+
+void timestamp_update(struct timeval *timestamp);
+time_t timestamp_age(const struct timeval *timestamp);
+
+struct proxy {
+	struct llist_head subscr_list;
+
+	/* How long to keep proxy entries without a refresh, in seconds. */
+	uint32_t fresh_time;
+	/* How often to garbage collect the proxy cache, period in seconds.
+	 * To change this and take effect immediately, rather use proxy_set_gc_period(). */
+	uint32_t gc_period;
+
+	struct osmo_timer_list gc_timer;
+};
 
 struct proxy_subscr {
 	char imsi[GSM23003_IMSI_MAX_DIGITS+1];
+	char msisdn[GSM23003_MSISDN_MAX_DIGITS+1];
+#if 0
+	/* Set if this is a middle proxy, i.e. a proxy behind another proxy. */
+	struct global_title vlr_via_proxy;
+#endif
+	struct global_title vlr_name;
 	struct osmo_sockaddr_str remote_hlr;
+	struct timeval last_lu;
 };
 
-void proxy_init(void *ctx);
-const struct proxy_subscr *proxy_subscr_get(const char *imsi);
-int proxy_subscr_update(const struct proxy_subscr *proxy_subscr);
-int proxy_subscr_del(const char *imsi);
-
-void timestamp_update(struct timeval *timestamp);
-time_t timestamp_age(const struct timeval *timestamp);
+struct proxy *proxy_init(void *ctx);
+void proxy_del(struct proxy *proxy);
+void proxy_set_gc_period(struct proxy *proxy, uint32_t gc_period);
+const struct proxy_subscr *proxy_subscr_get_by_imsi(struct proxy *proxy, const char *imsi);
+const struct proxy_subscr *proxy_subscr_get_by_msisdn(struct proxy *proxy, const char *msisdn);
+int proxy_subscr_update(struct proxy *proxy, const struct proxy_subscr *proxy_subscr);
+int proxy_subscr_del(struct proxy *proxy, const char *imsi);
diff --git a/tests/db/db_test.c b/tests/db/db_test.c
index 8902998..94295e1 100644
--- a/tests/db/db_test.c
+++ b/tests/db/db_test.c
@@ -241,7 +241,7 @@ static int db_subscr_lu_str(struct db_context *dbc, int64_t subscr_id,
 			    const char *vlr_or_sgsn_number, bool is_ps)
 {
 	struct global_title vlr_nr;
-	global_title_set(&vlr_nr, (uint8_t*)vlr_or_sgsn_number, vlr_or_sgsn_number ? strlen(vlr_or_sgsn_number)+1 : 0);
+	global_title_set_str(&vlr_nr, vlr_or_sgsn_number);
 	return db_subscr_lu(dbc, subscr_id, &vlr_nr, &vlr_nr, is_ps);
 }
 
diff --git a/tests/db_upgrade/db_upgrade_test.ok b/tests/db_upgrade/db_upgrade_test.ok
index 52b6735..f467f06 100644
--- a/tests/db_upgrade/db_upgrade_test.ok
+++ b/tests/db_upgrade/db_upgrade_test.ok
@@ -136,18 +136,19 @@ periodic_lu_tmr|INTEGER|0||0
 periodic_rau_tau_tmr|INTEGER|0||0
 sgsn_address|VARCHAR|0||0
 sgsn_number|VARCHAR(15)|0||0
+sgsn_via_proxy|VARCHAR|0||0
 smsc_number|VARCHAR(15)|0||0
 vlr_number|VARCHAR(15)|0||0
 vlr_via_proxy|VARCHAR|0||0
 
 Table subscriber contents:
-ggsn_number|gmlc_number|id|imei|imeisv|imsi|last_lu_seen|lmsi|ms_purged_cs|ms_purged_ps|msc_number|msisdn|nam_cs|nam_ps|periodic_lu_tmr|periodic_rau_tau_tmr|sgsn_address|sgsn_number|smsc_number|vlr_number|vlr_via_proxy
-||1|||123456789012345|||0|0||098765432109876|1|1||||||MSC-1|
-||2|||111111111|||1|0|||1|1|||||||
-||3|||222222222|||0|1||22222|1|1|||||||
-||4|||333333|||0|0||3|0|1|||||||
-||5|||444444444444444|||0|0||4444|1|0|||||||
-||6|||5555555|||0|0||55555555555555|0|0|||||||
+ggsn_number|gmlc_number|id|imei|imeisv|imsi|last_lu_seen|lmsi|ms_purged_cs|ms_purged_ps|msc_number|msisdn|nam_cs|nam_ps|periodic_lu_tmr|periodic_rau_tau_tmr|sgsn_address|sgsn_number|sgsn_via_proxy|smsc_number|vlr_number|vlr_via_proxy
+||1|||123456789012345|||0|0||098765432109876|1|1|||||||MSC-1|
+||2|||111111111|||1|0|||1|1||||||||
+||3|||222222222|||0|1||22222|1|1||||||||
+||4|||333333|||0|0||3|0|1||||||||
+||5|||444444444444444|||0|0||4444|1|0||||||||
+||6|||5555555|||0|0||55555555555555|0|0||||||||
 
 Table: subscriber_apn
 name|type|notnull|dflt_value|pk
diff --git a/tests/test_nodes.vty b/tests/test_nodes.vty
index 844b1fd..e36d6ad 100644
--- a/tests/test_nodes.vty
+++ b/tests/test_nodes.vty
@@ -119,8 +119,8 @@ OsmoHLR# configure terminal
 OsmoHLR(config)# mslookup
 OsmoHLR(config-mslookup)# list
 ...
-  dns
-  no dns
+  mdns
+  no mdns
   server
   no server
   client
@@ -129,8 +129,8 @@ OsmoHLR(config-mslookup)# list
 OsmoHLR(config-mslookup)# server
 OsmoHLR(config-mslookup-server)# list
 ...
-  dns bind multicast IP <1-65535>
-  no dns
+  mdns bind IP <1-65535>
+  no mdns
   service NAME at IP <1-65535>
   no service NAME
   no service NAME at IP <1-65535>
@@ -148,7 +148,7 @@ OsmoHLR(config-mslookup-server)# exit
 OsmoHLR(config-mslookup)# client
 OsmoHLR(config-mslookup-client)# list
 ...
-  timeout <1-255>
-  dns to multicast IP <1-65535>
-  no dns
+  timeout <1-100000>
+  mdns to IP <1-65535>
+  no mdns