migrate to oap_client in libosmogsm

libosmogsm in libosmocore.git from Change-Id
Ie36729996abd30b84d1c30a09f62ebc6a9794950 onwards contains oap_client.c,
so we don't need our local copy here in this repo anymore.

Change-Id: I7b194f98ef3f925b6178d8a8dbd9fcf2f0c6e132
Requires: libosmocore.git Change-Id Ie36729996abd30b84d1c30a09f62ebc6a9794950

5 files changed, 10 insertions, 571 deletions

diff --git a/src/gprs/Makefile.am b/src/gprs/Makefile.am
index 1cf67850c..46d94d456 100644
--- a/src/gprs/Makefile.am
+++ b/src/gprs/Makefile.am
@@ -84,7 +84,6 @@ osmo_sgsn_SOURCES = \
 	gprs_llc_xid.c \
 	v42bis.c \
 	gsup_client.c \
-	oap_client.c \
 	$(NULL)
 osmo_sgsn_LDADD = \
 	$(OSMO_LIBS) \
diff --git a/src/gprs/gsup_client.c b/src/gprs/gsup_client.c
index 48357b475..95c498898 100644
--- a/src/gprs/gsup_client.c
+++ b/src/gprs/gsup_client.c
@@ -116,7 +116,7 @@ static void gsup_client_oap_register(struct gsup_client *gsupc)
 {
 	struct msgb *msg_tx;
 	int rc;
-	rc = oap_client_register(&gsupc->oap_state, &msg_tx);
+	rc = osmo_oap_client_register(&gsupc->oap_state, &msg_tx);
 
 	if ((rc < 0) || (!msg_tx)) {
 		LOGP(DLGSUP, LOGL_ERROR, "GSUP OAP set up, but cannot register.\n");
@@ -138,7 +138,7 @@ static void gsup_client_updown_cb(struct ipa_client_conn *link, int up)
 	if (up) {
 		start_test_procedure(gsupc);
 
-		if (gsupc->oap_state.state == OAP_INITIALIZED)
+		if (gsupc->oap_state.state == OSMO_OAP_INITIALIZED)
 			gsup_client_oap_register(gsupc);
 
 		osmo_timer_del(&gsupc->connect_timer);
@@ -156,7 +156,7 @@ static int gsup_client_oap_handle(struct gsup_client *gsupc, struct msgb *msg_rx
 	struct msgb *msg_tx;
 
 	/* If the oap_state is disabled, this will reject the messages. */
-	rc = oap_client_handle(&gsupc->oap_state, msg_rx, &msg_tx);
+	rc = osmo_oap_client_handle(&gsupc->oap_state, msg_rx, &msg_tx);
 	msgb_free(msg_rx);
 	if (rc < 0)
 		return rc;
@@ -269,7 +269,7 @@ struct gsup_client *gsup_client_create(const char *unit_name,
 				       const char *ip_addr,
 				       unsigned int tcp_port,
 				       gsup_client_read_cb_t read_cb,
-				       struct oap_client_config *oapc_config)
+				       struct osmo_oap_client_config *oapc_config)
 {
 	struct gsup_client *gsupc;
 	int rc;
@@ -284,7 +284,7 @@ struct gsup_client *gsup_client_create(const char *unit_name,
 	OSMO_ASSERT(gsupc->unit_name);
 
 	/* a NULL oapc_config will mark oap_state disabled. */
-	rc = oap_client_init(oapc_config, &gsupc->oap_state);
+	rc = osmo_oap_client_init(oapc_config, &gsupc->oap_state);
 	if (rc != 0)
 		goto failed;
 
diff --git a/src/gprs/oap_client.c b/src/gprs/oap_client.c
deleted file mode 100644
index 9ff84a6ea..000000000
--- a/src/gprs/oap_client.c
+++ /dev/null
@@ -1,280 +0,0 @@
-/* Osmocom Authentication Protocol API */
-
-/* (C) 2015 by Sysmocom s.f.m.c. GmbH
- * All Rights Reserved
- *
- * Author: Neels Hofmeyr
- *
- * 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 <string.h>
-#include <errno.h>
-
-#include <osmocom/core/utils.h>
-#include <osmocom/crypt/auth.h>
-#include <osmocom/gsm/oap.h>
-
-#include <osmocom/sgsn/oap_client.h>
-#include <osmocom/sgsn/debug.h>
-
-int oap_client_init(struct oap_client_config *config,
-		    struct oap_client_state *state)
-{
-	OSMO_ASSERT(state->state == OAP_UNINITIALIZED);
-
-	if (!config)
-		goto disable;
-
-	if (config->client_id == 0)
-		goto disable;
-
-	if (config->secret_k_present == 0) {
-		LOGP(DLOAP, LOGL_NOTICE, "OAP: client ID set, but secret K missing.\n");
-		goto disable;
-	}
-
-	if (config->secret_opc_present == 0) {
-		LOGP(DLOAP, LOGL_NOTICE, "OAP: client ID set, but secret OPC missing.\n");
-		goto disable;
-	}
-
-	state->client_id = config->client_id;
-	memcpy(state->secret_k, config->secret_k, sizeof(state->secret_k));
-	memcpy(state->secret_opc, config->secret_opc, sizeof(state->secret_opc));
-	state->state = OAP_INITIALIZED;
-	return 0;
-
-disable:
-	state->state = OAP_DISABLED;
-	return 0;
-}
-
-/* From the given state and received RAND and AUTN octets, validate the
- * server's authenticity and formulate the matching milenage reply octets in
- * *tx_xres. The state is not modified.
- * On success, and if tx_res is not NULL, exactly 8 octets will be written to
- * *tx_res. If not NULL, tx_res must point at allocated memory of at least 8
- * octets. The caller will want to send XRES back to the server in a challenge
- * response message and update the state.
- * Return 0 on success; -1 if OAP is disabled; -2 if rx_random and rx_autn fail
- * the authentication check; -3 for any other errors. */
-static int oap_evaluate_challenge(const struct oap_client_state *state,
-				  const uint8_t *rx_random,
-				  const uint8_t *rx_autn,
-				  uint8_t *tx_xres)
-{
-	struct osmo_auth_vector vec;
-
-	struct osmo_sub_auth_data auth = {
-		.type		= OSMO_AUTH_TYPE_UMTS,
-		.algo		= OSMO_AUTH_ALG_MILENAGE,
-	};
-
-	osmo_static_assert(sizeof(((struct osmo_sub_auth_data*)0)->u.umts.k)
-			   == sizeof(state->secret_k), _secret_k_size_match);
-	osmo_static_assert(sizeof(((struct osmo_sub_auth_data*)0)->u.umts.opc)
-			   == sizeof(state->secret_opc), _secret_opc_size_match);
-
-	switch (state->state) {
-	case OAP_UNINITIALIZED:
-	case OAP_DISABLED:
-		return -1;
-	default:
-		break;
-	}
-
-	memcpy(auth.u.umts.k, state->secret_k, sizeof(auth.u.umts.k));
-	memcpy(auth.u.umts.opc, state->secret_opc, sizeof(auth.u.umts.opc));
-	memset(auth.u.umts.amf, '\0', sizeof(auth.u.umts.amf));
-	auth.u.umts.sqn = 41; /* TODO use incrementing sequence nr */
-
-	memset(&vec, 0, sizeof(vec));
-	osmo_auth_gen_vec(&vec, &auth, rx_random);
-
-	if (vec.res_len != 8) {
-		LOGP(DLOAP, LOGL_ERROR, "OAP: Expected XRES to be 8 octets, got %d\n",
-		     vec.res_len);
-		return -3;
-	}
-
-	if (osmo_constant_time_cmp(vec.autn, rx_autn, sizeof(vec.autn)) != 0) {
-		LOGP(DLOAP, LOGL_ERROR, "OAP: AUTN mismatch!\n");
-		LOGP(DLOAP, LOGL_INFO, "OAP: AUTN from server: %s\n",
-		     osmo_hexdump_nospc(rx_autn, sizeof(vec.autn)));
-		LOGP(DLOAP, LOGL_INFO, "OAP: AUTN expected:    %s\n",
-		     osmo_hexdump_nospc(vec.autn, sizeof(vec.autn)));
-		return -2;
-	}
-
-	if (tx_xres != NULL)
-		memcpy(tx_xres, vec.res, 8);
-	return 0;
-}
-
-struct msgb *oap_client_encoded(const struct osmo_oap_message *oap_msg)
-{
-	struct msgb *msg = msgb_alloc_headroom(1000, 64, __func__);
-	OSMO_ASSERT(msg);
-	osmo_oap_encode(msg, oap_msg);
-	return msg;
-}
-
-/* Create a new msgb containing an OAP registration message.
- * On error, return NULL. */
-static struct msgb* oap_msg_register(uint16_t client_id)
-{
-	struct osmo_oap_message oap_msg = {0};
-
-	if (client_id < 1) {
-		LOGP(DLOAP, LOGL_ERROR, "OAP: Invalid client ID: %d\n", client_id);
-		return NULL;
-	}
-
-	oap_msg.message_type = OAP_MSGT_REGISTER_REQUEST;
-	oap_msg.client_id = client_id;
-	return oap_client_encoded(&oap_msg);
-}
-
-int oap_client_register(struct oap_client_state *state, struct msgb **msg_tx)
-{
-	*msg_tx = oap_msg_register(state->client_id);
-	if (!(*msg_tx))
-		return -1;
-
-	state->state = OAP_REQUESTED_CHALLENGE;
-	return 0;
-}
-
-/* Create a new msgb containing an OAP challenge response message.
- * xres must point at 8 octets to return as challenge response.
- * On error, return NULL. */
-static struct msgb* oap_msg_challenge_response(uint8_t *xres)
-{
-	struct osmo_oap_message oap_reply = {0};
-
-	oap_reply.message_type = OAP_MSGT_CHALLENGE_RESULT;
-	memcpy(oap_reply.xres, xres, sizeof(oap_reply.xres));
-	oap_reply.xres_present = 1;
-	return oap_client_encoded(&oap_reply);
-}
-
-static int handle_challenge(struct oap_client_state *state,
-			    struct osmo_oap_message *oap_rx,
-			    struct msgb **msg_tx)
-{
-	int rc;
-	uint8_t xres[8];
-
-	if (!(oap_rx->rand_present && oap_rx->autn_present)) {
-		LOGP(DLOAP, LOGL_ERROR,
-		     "OAP challenge incomplete (rand_present: %d, autn_present: %d)\n",
-		     oap_rx->rand_present, oap_rx->autn_present);
-		rc = -2;
-		goto failure;
-	}
-
-	rc = oap_evaluate_challenge(state,
-				    oap_rx->rand,
-				    oap_rx->autn,
-				    xres);
-	if (rc < 0)
-		goto failure;
-
-	*msg_tx = oap_msg_challenge_response(xres);
-	if ((*msg_tx) == NULL) {
-		rc = -1;
-		goto failure;
-	}
-
-	state->state = OAP_SENT_CHALLENGE_RESULT;
-	return 0;
-
-failure:
-	OSMO_ASSERT(rc < 0);
-	state->state = OAP_INITIALIZED;
-	return rc;
-}
-
-int oap_client_handle(struct oap_client_state *state,
-		      const struct msgb *msg_rx, struct msgb **msg_tx)
-{
-	uint8_t *data = msgb_l2(msg_rx);
-	size_t data_len = msgb_l2len(msg_rx);
-	struct osmo_oap_message oap_msg = {0};
-	int rc = 0;
-
-	*msg_tx = NULL;
-
-	OSMO_ASSERT(data);
-
-	rc = osmo_oap_decode(&oap_msg, data, data_len);
-	if (rc < 0) {
-		LOGP(DLOAP, LOGL_ERROR,
-		     "Decoding OAP message failed with error '%s' (%d)\n",
-		     get_value_string(gsm48_gmm_cause_names, -rc), -rc);
-		return -10;
-	}
-
-	switch (state->state) {
-	case OAP_UNINITIALIZED:
-		LOGP(DLOAP, LOGL_ERROR,
-		     "Received OAP message %d, but the OAP client is"
-		     " not initialized\n", oap_msg.message_type);
-		return -ENOTCONN;
-	case OAP_DISABLED:
-		LOGP(DLOAP, LOGL_ERROR,
-		     "Received OAP message %d, but the OAP client is"
-		     " disabled\n", oap_msg.message_type);
-		return -ENOTCONN;
-	default:
-		break;
-	}
-
-	switch (oap_msg.message_type) {
-	case OAP_MSGT_CHALLENGE_REQUEST:
-		return handle_challenge(state, &oap_msg, msg_tx);
-
-	case OAP_MSGT_REGISTER_RESULT:
-		/* successfully registered */
-		state->state = OAP_REGISTERED;
-		break;
-
-	case OAP_MSGT_REGISTER_ERROR:
-		LOGP(DLOAP, LOGL_ERROR,
-		     "OAP registration failed\n");
-		state->state = OAP_INITIALIZED;
-		if (state->registration_failures < 3) {
-			state->registration_failures ++;
-			return oap_client_register(state, msg_tx);
-		}
-		return -11;
-
-	case OAP_MSGT_REGISTER_REQUEST:
-	case OAP_MSGT_CHALLENGE_RESULT:
-		LOGP(DLOAP, LOGL_ERROR,
-		     "Received invalid OAP message type for OAP client side: %d\n",
-		     (int)oap_msg.message_type);
-		return -12;
-
-	default:
-		LOGP(DLOAP, LOGL_ERROR,
-		     "Unknown OAP message type: %d\n",
-		     (int)oap_msg.message_type);
-		return -13;
-	}
-
-	return 0;
-}
diff --git a/src/libcommon/gsup_client.c b/src/libcommon/gsup_client.c
index 89a9f7060..052004548 100644
--- a/src/libcommon/gsup_client.c
+++ b/src/libcommon/gsup_client.c
@@ -116,7 +116,7 @@ static void gsup_client_oap_register(struct gsup_client *gsupc)
 {
 	struct msgb *msg_tx;
 	int rc;
-	rc = oap_client_register(&gsupc->oap_state, &msg_tx);
+	rc = osmo_oap_client_register(&gsupc->oap_state, &msg_tx);
 
 	if ((rc < 0) || (!msg_tx)) {
 		LOGP(DLGSUP, LOGL_ERROR, "GSUP OAP set up, but cannot register.\n");
@@ -138,7 +138,7 @@ static void gsup_client_updown_cb(struct ipa_client_conn *link, int up)
 	if (up) {
 		start_test_procedure(gsupc);
 
-		if (gsupc->oap_state.state == OAP_INITIALIZED)
+		if (gsupc->osmo_oap_state.state == OSMO_OAP_INITIALIZED)
 			gsup_client_oap_register(gsupc);
 
 		osmo_timer_del(&gsupc->connect_timer);
@@ -156,7 +156,7 @@ static int gsup_client_oap_handle(struct gsup_client *gsupc, struct msgb *msg_rx
 	struct msgb *msg_tx;
 
 	/* If the oap_state is disabled, this will reject the messages. */
-	rc = oap_client_handle(&gsupc->oap_state, msg_rx, &msg_tx);
+	rc = osmo_oap_client_handle(&gsupc->oap_state, msg_rx, &msg_tx);
 	msgb_free(msg_rx);
 	if (rc < 0)
 		return rc;
@@ -269,7 +269,7 @@ struct gsup_client *gsup_client_create(const char *unit_name,
 				       const char *ip_addr,
 				       unsigned int tcp_port,
 				       gsup_client_read_cb_t read_cb,
-				       struct oap_client_config *oapc_config)
+				       struct osmo_oap_client_config *oapc_config)
 {
 	struct gsup_client *gsupc;
 	int rc;
@@ -284,7 +284,7 @@ struct gsup_client *gsup_client_create(const char *unit_name,
 	OSMO_ASSERT(gsupc->unit_name);
 
 	/* a NULL oapc_config will mark oap_state disabled. */
-	rc = oap_client_init(oapc_config, &gsupc->oap_state);
+	rc = osmo_oap_client_init(oapc_config, &gsupc->oap_state);
 	if (rc != 0)
 		goto failed;
 
diff --git a/src/libcommon/oap_client.c b/src/libcommon/oap_client.c
deleted file mode 100644
index 9ff84a6ea..000000000
--- a/src/libcommon/oap_client.c
+++ /dev/null
@@ -1,280 +0,0 @@
-/* Osmocom Authentication Protocol API */
-
-/* (C) 2015 by Sysmocom s.f.m.c. GmbH
- * All Rights Reserved
- *
- * Author: Neels Hofmeyr
- *
- * 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 <string.h>
-#include <errno.h>
-
-#include <osmocom/core/utils.h>
-#include <osmocom/crypt/auth.h>
-#include <osmocom/gsm/oap.h>
-
-#include <osmocom/sgsn/oap_client.h>
-#include <osmocom/sgsn/debug.h>
-
-int oap_client_init(struct oap_client_config *config,
-		    struct oap_client_state *state)
-{
-	OSMO_ASSERT(state->state == OAP_UNINITIALIZED);
-
-	if (!config)
-		goto disable;
-
-	if (config->client_id == 0)
-		goto disable;
-
-	if (config->secret_k_present == 0) {
-		LOGP(DLOAP, LOGL_NOTICE, "OAP: client ID set, but secret K missing.\n");
-		goto disable;
-	}
-
-	if (config->secret_opc_present == 0) {
-		LOGP(DLOAP, LOGL_NOTICE, "OAP: client ID set, but secret OPC missing.\n");
-		goto disable;
-	}
-
-	state->client_id = config->client_id;
-	memcpy(state->secret_k, config->secret_k, sizeof(state->secret_k));
-	memcpy(state->secret_opc, config->secret_opc, sizeof(state->secret_opc));
-	state->state = OAP_INITIALIZED;
-	return 0;
-
-disable:
-	state->state = OAP_DISABLED;
-	return 0;
-}
-
-/* From the given state and received RAND and AUTN octets, validate the
- * server's authenticity and formulate the matching milenage reply octets in
- * *tx_xres. The state is not modified.
- * On success, and if tx_res is not NULL, exactly 8 octets will be written to
- * *tx_res. If not NULL, tx_res must point at allocated memory of at least 8
- * octets. The caller will want to send XRES back to the server in a challenge
- * response message and update the state.
- * Return 0 on success; -1 if OAP is disabled; -2 if rx_random and rx_autn fail
- * the authentication check; -3 for any other errors. */
-static int oap_evaluate_challenge(const struct oap_client_state *state,
-				  const uint8_t *rx_random,
-				  const uint8_t *rx_autn,
-				  uint8_t *tx_xres)
-{
-	struct osmo_auth_vector vec;
-
-	struct osmo_sub_auth_data auth = {
-		.type		= OSMO_AUTH_TYPE_UMTS,
-		.algo		= OSMO_AUTH_ALG_MILENAGE,
-	};
-
-	osmo_static_assert(sizeof(((struct osmo_sub_auth_data*)0)->u.umts.k)
-			   == sizeof(state->secret_k), _secret_k_size_match);
-	osmo_static_assert(sizeof(((struct osmo_sub_auth_data*)0)->u.umts.opc)
-			   == sizeof(state->secret_opc), _secret_opc_size_match);
-
-	switch (state->state) {
-	case OAP_UNINITIALIZED:
-	case OAP_DISABLED:
-		return -1;
-	default:
-		break;
-	}
-
-	memcpy(auth.u.umts.k, state->secret_k, sizeof(auth.u.umts.k));
-	memcpy(auth.u.umts.opc, state->secret_opc, sizeof(auth.u.umts.opc));
-	memset(auth.u.umts.amf, '\0', sizeof(auth.u.umts.amf));
-	auth.u.umts.sqn = 41; /* TODO use incrementing sequence nr */
-
-	memset(&vec, 0, sizeof(vec));
-	osmo_auth_gen_vec(&vec, &auth, rx_random);
-
-	if (vec.res_len != 8) {
-		LOGP(DLOAP, LOGL_ERROR, "OAP: Expected XRES to be 8 octets, got %d\n",
-		     vec.res_len);
-		return -3;
-	}
-
-	if (osmo_constant_time_cmp(vec.autn, rx_autn, sizeof(vec.autn)) != 0) {
-		LOGP(DLOAP, LOGL_ERROR, "OAP: AUTN mismatch!\n");
-		LOGP(DLOAP, LOGL_INFO, "OAP: AUTN from server: %s\n",
-		     osmo_hexdump_nospc(rx_autn, sizeof(vec.autn)));
-		LOGP(DLOAP, LOGL_INFO, "OAP: AUTN expected:    %s\n",
-		     osmo_hexdump_nospc(vec.autn, sizeof(vec.autn)));
-		return -2;
-	}
-
-	if (tx_xres != NULL)
-		memcpy(tx_xres, vec.res, 8);
-	return 0;
-}
-
-struct msgb *oap_client_encoded(const struct osmo_oap_message *oap_msg)
-{
-	struct msgb *msg = msgb_alloc_headroom(1000, 64, __func__);
-	OSMO_ASSERT(msg);
-	osmo_oap_encode(msg, oap_msg);
-	return msg;
-}
-
-/* Create a new msgb containing an OAP registration message.
- * On error, return NULL. */
-static struct msgb* oap_msg_register(uint16_t client_id)
-{
-	struct osmo_oap_message oap_msg = {0};
-
-	if (client_id < 1) {
-		LOGP(DLOAP, LOGL_ERROR, "OAP: Invalid client ID: %d\n", client_id);
-		return NULL;
-	}
-
-	oap_msg.message_type = OAP_MSGT_REGISTER_REQUEST;
-	oap_msg.client_id = client_id;
-	return oap_client_encoded(&oap_msg);
-}
-
-int oap_client_register(struct oap_client_state *state, struct msgb **msg_tx)
-{
-	*msg_tx = oap_msg_register(state->client_id);
-	if (!(*msg_tx))
-		return -1;
-
-	state->state = OAP_REQUESTED_CHALLENGE;
-	return 0;
-}
-
-/* Create a new msgb containing an OAP challenge response message.
- * xres must point at 8 octets to return as challenge response.
- * On error, return NULL. */
-static struct msgb* oap_msg_challenge_response(uint8_t *xres)
-{
-	struct osmo_oap_message oap_reply = {0};
-
-	oap_reply.message_type = OAP_MSGT_CHALLENGE_RESULT;
-	memcpy(oap_reply.xres, xres, sizeof(oap_reply.xres));
-	oap_reply.xres_present = 1;
-	return oap_client_encoded(&oap_reply);
-}
-
-static int handle_challenge(struct oap_client_state *state,
-			    struct osmo_oap_message *oap_rx,
-			    struct msgb **msg_tx)
-{
-	int rc;
-	uint8_t xres[8];
-
-	if (!(oap_rx->rand_present && oap_rx->autn_present)) {
-		LOGP(DLOAP, LOGL_ERROR,
-		     "OAP challenge incomplete (rand_present: %d, autn_present: %d)\n",
-		     oap_rx->rand_present, oap_rx->autn_present);
-		rc = -2;
-		goto failure;
-	}
-
-	rc = oap_evaluate_challenge(state,
-				    oap_rx->rand,
-				    oap_rx->autn,
-				    xres);
-	if (rc < 0)
-		goto failure;
-
-	*msg_tx = oap_msg_challenge_response(xres);
-	if ((*msg_tx) == NULL) {
-		rc = -1;
-		goto failure;
-	}
-
-	state->state = OAP_SENT_CHALLENGE_RESULT;
-	return 0;
-
-failure:
-	OSMO_ASSERT(rc < 0);
-	state->state = OAP_INITIALIZED;
-	return rc;
-}
-
-int oap_client_handle(struct oap_client_state *state,
-		      const struct msgb *msg_rx, struct msgb **msg_tx)
-{
-	uint8_t *data = msgb_l2(msg_rx);
-	size_t data_len = msgb_l2len(msg_rx);
-	struct osmo_oap_message oap_msg = {0};
-	int rc = 0;
-
-	*msg_tx = NULL;
-
-	OSMO_ASSERT(data);
-
-	rc = osmo_oap_decode(&oap_msg, data, data_len);
-	if (rc < 0) {
-		LOGP(DLOAP, LOGL_ERROR,
-		     "Decoding OAP message failed with error '%s' (%d)\n",
-		     get_value_string(gsm48_gmm_cause_names, -rc), -rc);
-		return -10;
-	}
-
-	switch (state->state) {
-	case OAP_UNINITIALIZED:
-		LOGP(DLOAP, LOGL_ERROR,
-		     "Received OAP message %d, but the OAP client is"
-		     " not initialized\n", oap_msg.message_type);
-		return -ENOTCONN;
-	case OAP_DISABLED:
-		LOGP(DLOAP, LOGL_ERROR,
-		     "Received OAP message %d, but the OAP client is"
-		     " disabled\n", oap_msg.message_type);
-		return -ENOTCONN;
-	default:
-		break;
-	}
-
-	switch (oap_msg.message_type) {
-	case OAP_MSGT_CHALLENGE_REQUEST:
-		return handle_challenge(state, &oap_msg, msg_tx);
-
-	case OAP_MSGT_REGISTER_RESULT:
-		/* successfully registered */
-		state->state = OAP_REGISTERED;
-		break;
-
-	case OAP_MSGT_REGISTER_ERROR:
-		LOGP(DLOAP, LOGL_ERROR,
-		     "OAP registration failed\n");
-		state->state = OAP_INITIALIZED;
-		if (state->registration_failures < 3) {
-			state->registration_failures ++;
-			return oap_client_register(state, msg_tx);
-		}
-		return -11;
-
-	case OAP_MSGT_REGISTER_REQUEST:
-	case OAP_MSGT_CHALLENGE_RESULT:
-		LOGP(DLOAP, LOGL_ERROR,
-		     "Received invalid OAP message type for OAP client side: %d\n",
-		     (int)oap_msg.message_type);
-		return -12;
-
-	default:
-		LOGP(DLOAP, LOGL_ERROR,
-		     "Unknown OAP message type: %d\n",
-		     (int)oap_msg.message_type);
-		return -13;
-	}
-
-	return 0;
-}