osmo-msc/src/libmsc/gsm_04_11.c

/* Point-to-Point (PP) Short Message Service (SMS)
 * Support on Mobile Radio Interface
 * 3GPP TS 04.11 version 7.1.0 Release 1998 / ETSI TS 100 942 V7.1.0 */

/* (C) 2008 by Daniel Willmann <daniel@totalueberwachung.de>
 * (C) 2009 by Harald Welte <laforge@gnumonks.org>
 * (C) 2010-2012 by Holger Hans Peter Freyther <zecke@selfish.org>
 * (C) 2010 by On-Waves
 * (C) 2011 by Andreas Eversberg <jolly@eversberg.eu>
 *
 * All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <time.h>
#include <netinet/in.h>

#include "bscconfig.h"

#include <osmocom/core/msgb.h>
#include <osmocom/core/talloc.h>
#include <osmocom/core/utils.h>

#include <osmocom/gsm/gsm_utils.h>
#include <osmocom/gsm/gsm0411_utils.h>
#include <osmocom/gsm/protocol/gsm_04_11.h>

#include <osmocom/msc/debug.h>
#include <osmocom/msc/gsm_data.h>
#include <osmocom/msc/db.h>
#include <osmocom/msc/gsm_subscriber.h>
#include <osmocom/msc/gsm_04_08.h>
#include <osmocom/msc/signal.h>
#include <osmocom/msc/db.h>
#include <osmocom/msc/transaction.h>
#include <osmocom/msc/msc_ifaces.h>
#include <osmocom/msc/vlr.h>

#ifdef BUILD_SMPP
#include "smpp_smsc.h"
#endif

void *tall_gsms_ctx;
static uint32_t new_callref = 0x40000001;


struct gsm_sms *sms_alloc(void)
{
	return talloc_zero(tall_gsms_ctx, struct gsm_sms);
}

void sms_free(struct gsm_sms *sms)
{
	/* drop references to subscriber structure */
	if (sms->receiver)
		vlr_subscr_put(sms->receiver, VSUB_USE_SMS_RECEIVER);
#ifdef BUILD_SMPP
	if (sms->smpp.esme)
		smpp_esme_put(sms->smpp.esme);
#endif

	talloc_free(sms);
}

struct gsm_sms *sms_from_text(struct vlr_subscr *receiver,
			      const char *sender_msisdn,
                              int dcs, const char *text)
{
	struct gsm_sms *sms = sms_alloc();

	if (!sms)
		return NULL;

	vlr_subscr_get(receiver, VSUB_USE_SMS_RECEIVER);
	sms->receiver = receiver;
	OSMO_STRLCPY_ARRAY(sms->text, text);

	OSMO_STRLCPY_ARRAY(sms->src.addr, sender_msisdn);
	sms->reply_path_req = 0;
	sms->status_rep_req = 0;
	sms->ud_hdr_ind = 0;
	sms->protocol_id = 0; /* implicit */
	sms->data_coding_scheme = dcs;
	OSMO_STRLCPY_ARRAY(sms->dst.addr, receiver->msisdn);
	/* Generate user_data */
	sms->user_data_len = gsm_7bit_encode_n(sms->user_data, sizeof(sms->user_data),
						sms->text, NULL);

	return sms;
}


static void send_signal(int sig_no,
			struct gsm_trans *trans,
			struct gsm_sms *sms,
			int paging_result)
{
	struct sms_signal_data sig;
	sig.trans = trans;
	sig.sms = sms;
	sig.paging_result = paging_result;
	osmo_signal_dispatch(SS_SMS, sig_no, &sig);
}

static int gsm411_sendmsg(struct ran_conn *conn, struct msgb *msg)
{
	DEBUGP(DLSMS, "GSM4.11 TX %s\n", msgb_hexdump(msg));
	msg->l3h = msg->data;
	return msc_tx_dtap(conn, msg);
}

/* Paging callback for MT SMS (Paging is triggered by SMC) */
static int paging_cb_mmsms_est_req(unsigned int hooknum, unsigned int event,
				   struct msgb *msg, void *_conn, void *_trans)
{
	struct ran_conn *conn = _conn;
	struct gsm_trans *trans = _trans;
	struct gsm_sms *sms = trans->sms.sms;
	int rc = 0;

	DEBUGP(DLSMS, "paging_cb_mmsms_est_req(hooknum=%u, event=%u)\n", hooknum, event);

	if (hooknum != GSM_HOOK_RR_PAGING)
		return -EINVAL;

	/* Paging procedure has finished */
	trans->paging_request = NULL;

	switch (event) {
	case GSM_PAGING_SUCCEEDED:
		/* Associate transaction with established connection */
		trans->conn = ran_conn_get(conn, RAN_CONN_USE_TRANS_SMS);
		/* Confirm successful connection establishment */
		gsm411_smc_recv(&trans->sms.smc_inst,
			GSM411_MMSMS_EST_CNF, NULL, 0);
		break;
	case GSM_PAGING_EXPIRED:
	case GSM_PAGING_BUSY:
		/* Inform SMC about channel establishment failure */
		gsm411_smc_recv(&trans->sms.smc_inst,
			GSM411_MMSMS_REL_IND, NULL, 0);

		/* gsm411_send_rp_data() doesn't set trans->sms.sms */
		if (sms != NULL) {
			/* Notify the SMSqueue and free stored SMS */
			send_signal(S_SMS_UNKNOWN_ERROR, NULL, sms, event);
			trans->sms.sms = NULL;
			sms_free(sms);
		}

		/* Destroy this transaction */
		trans_free(trans);
		rc = -ETIMEDOUT;
		break;
	default:
		LOGP(DLSMS, LOGL_ERROR, "Unhandled paging event: %d\n", event);
	}

	return rc;
}

static int gsm411_mmsms_est_req(struct gsm_trans *trans)
{
	/* Subscriber's data shall be associated */
	OSMO_ASSERT(trans->vsub != NULL);

	/* Check if connection is already established */
	if (trans->conn != NULL) {
		LOGP(DLSMS, LOGL_DEBUG, "Using an existing connection "
			"for %s\n", vlr_subscr_name(trans->vsub));
		return gsm411_smc_recv(&trans->sms.smc_inst,
			GSM411_MMSMS_EST_CNF, NULL, 0);
	}

	/* Initiate Paging procedure */
	LOGP(DLSMS, LOGL_DEBUG, "Initiating Paging procedure "
		"for %s due to MMSMS_EST_REQ\n", vlr_subscr_name(trans->vsub));
	trans->paging_request = subscr_request_conn(trans->vsub,
						    paging_cb_mmsms_est_req,
						    trans, "MT SMS",
						    SGSAP_SERV_IND_SMS);
	if (!trans->paging_request) {
		LOGP(DLSMS, LOGL_ERROR, "Failed to initiate Paging "
			"procedure for %s\n", vlr_subscr_name(trans->vsub));
		/* Inform SMC about channel establishment failure */
		gsm411_smc_recv(&trans->sms.smc_inst,
			GSM411_MMSMS_REL_IND, NULL, 0);
		trans_free(trans);
		return -EIO;
	}

	return 0;
}

/* Prefix msg with a 04.08/04.11 CP header */
static int gsm411_cp_sendmsg(struct msgb *msg, struct gsm_trans *trans,
			     uint8_t msg_type)
{
	struct gsm48_hdr *gh;

	gh = (struct gsm48_hdr *) msgb_push(msg, sizeof(*gh));
	/* Outgoing needs the highest bit set */
	gh->proto_discr = trans->protocol | (trans->transaction_id<<4);
	gh->msg_type = msg_type;
	OMSC_LINKID_CB(msg) = trans->dlci;

	DEBUGP(DLSMS, "sending CP message (trans=%x)\n", trans->transaction_id);

	return gsm411_sendmsg(trans->conn, msg);
}

/* mm_send: receive MMCCSMS sap message from SMC */
static int gsm411_mm_send(struct gsm411_smc_inst *inst, int msg_type,
			struct msgb *msg, int cp_msg_type)
{
	struct gsm_trans *trans =
		container_of(inst, struct gsm_trans, sms.smc_inst);
	int rc = 0;

	switch (msg_type) {
	case GSM411_MMSMS_EST_REQ:
		rc = gsm411_mmsms_est_req(trans);
		msgb_free(msg); /* upper layer does not free msg */
		break;
	case GSM411_MMSMS_DATA_REQ:
		rc = gsm411_cp_sendmsg(msg, trans, cp_msg_type);
		break;
	case GSM411_MMSMS_REL_REQ:
		DEBUGP(DLSMS, "Got MMSMS_REL_REQ, destroying transaction.\n");
		msgb_free(msg);
		trans_free(trans);
		break;
	default:
		LOGP(DLSMS, LOGL_NOTICE, "Unhandled MMCCSMS msg 0x%x\n", msg_type);
		msgb_free(msg);
		rc = -EINVAL;
	}

	return rc;
}

/* mm_send: receive MNCCSMS sap message from SMR */
int gsm411_mn_send(struct gsm411_smr_inst *inst, int msg_type,
			struct msgb *msg)
{
	struct gsm_trans *trans =
		container_of(inst, struct gsm_trans, sms.smr_inst);

	/* forward to SMC */
	return gsm411_smc_send(&trans->sms.smc_inst, msg_type, msg);
}

static int gsm340_rx_sms_submit(struct gsm_sms *gsms)
{
	if (db_sms_store(gsms) != 0) {
		LOGP(DLSMS, LOGL_ERROR, "Failed to store SMS in Database\n");
		return GSM411_RP_CAUSE_MO_NET_OUT_OF_ORDER;
	}
	/* dispatch a signal to tell higher level about it */
	send_signal(S_SMS_SUBMITTED, NULL, gsms, 0);

	return 0;
}

/* generate a TPDU address field compliant with 03.40 sec. 9.1.2.5 */
static int gsm340_gen_oa_sub(uint8_t *oa, unsigned int oa_len,
			 const struct gsm_sms_addr *src)
{
	/* network specific, private numbering plan */
	return gsm340_gen_oa(oa, oa_len, src->ton, src->npi, src->addr);
}

/* generate a msgb containing an 03.40 9.2.2.1 SMS-DELIVER TPDU derived from
 * struct gsm_sms, returns total size of TPDU */
static int gsm340_gen_sms_deliver_tpdu(struct msgb *msg, struct gsm_sms *sms)
{
	uint8_t *smsp;
	uint8_t oa[12];	/* max len per 03.40 */
	uint8_t octet_len;
	unsigned int old_msg_len = msg->len;
	int oa_len;

	/* generate first octet with masked bits */
	smsp = msgb_put(msg, 1);
	/* TP-MTI (message type indicator) */
	*smsp = GSM340_SMS_DELIVER_SC2MS;
	/* TP-MMS (more messages to send) */
	if (0 /* FIXME */)
		*smsp |= 0x04;
	/* TP-SRI(deliver)/SRR(submit) */
	if (sms->status_rep_req)
		*smsp |= 0x20;
	/* TP-UDHI (indicating TP-UD contains a header) */
	if (sms->ud_hdr_ind)
		*smsp |= 0x40;

	/* generate originator address */
	oa_len = gsm340_gen_oa_sub(oa, sizeof(oa), &sms->src);
	if (oa_len < 0)
		return -ENOSPC;

	smsp = msgb_put(msg, oa_len);
	memcpy(smsp, oa, oa_len);

	/* generate TP-PID */
	smsp = msgb_put(msg, 1);
	*smsp = sms->protocol_id;

	/* generate TP-DCS */
	smsp = msgb_put(msg, 1);
	*smsp = sms->data_coding_scheme;

	/* generate TP-SCTS */
	smsp = msgb_put(msg, 7);
	gsm340_gen_scts(smsp, time(NULL));

	/* generate TP-UDL */
	smsp = msgb_put(msg, 1);
	*smsp = sms->user_data_len;

	/* generate TP-UD */
	switch (gsm338_get_sms_alphabet(sms->data_coding_scheme)) {
	case DCS_7BIT_DEFAULT:
		octet_len = sms->user_data_len*7/8;
		if (sms->user_data_len*7%8 != 0)
			octet_len++;
		/* Warning, user_data_len indicates the amount of septets
		 * (characters), we need amount of octets occupied */
		smsp = msgb_put(msg, octet_len);
		memcpy(smsp, sms->user_data, octet_len);
		break;
	case DCS_UCS2:
	case DCS_8BIT_DATA:
		smsp = msgb_put(msg, sms->user_data_len);
		memcpy(smsp, sms->user_data, sms->user_data_len);
		break;
	default:
		LOGP(DLSMS, LOGL_NOTICE, "Unhandled Data Coding Scheme: 0x%02X\n",
		     sms->data_coding_scheme);
		break;
	}

	return msg->len - old_msg_len;
}

/* As defined by GSM 03.40, Section 9.2.2.3. */
static int gsm340_gen_sms_status_report_tpdu(struct msgb *msg,
					     struct gsm_sms *sms)
{
	unsigned int old_msg_len = msg->len;
	uint8_t oa[12];	/* max len per 03.40 */
	uint8_t *smsp;
	int oa_len;

	/* generate first octet with masked bits */
	smsp = msgb_put(msg, 1);
	/* TP-MTI (message type indicator) */
	*smsp = GSM340_SMS_STATUS_REP_SC2MS;
	/* TP-MMS (more messages to send) */
	if (0 /* FIXME */)
		*smsp |= 0x04;
	/* TP-MR (message reference) */
	smsp = msgb_put(msg, 1);
	*smsp = sms->msg_ref;

	/* generate recipient address */
	oa_len = gsm340_gen_oa_sub(oa, sizeof(oa), &sms->src);
	if (oa_len < 0)
		return -ENOSPC;

	smsp = msgb_put(msg, oa_len);
	memcpy(smsp, oa, oa_len);

	/* generate TP-SCTS (Service centre timestamp) */
	smsp = msgb_put(msg, 7);
	gsm340_gen_scts(smsp, sms->created);

	/* generate TP-DT (Discharge time, in TP-SCTS format). */
	smsp = msgb_put(msg, 7);
	gsm340_gen_scts(smsp, sms->created);

	/* TP-ST (status) */
	smsp = msgb_put(msg, 1);
	/* From GSM 03.40, Section 9.2.3.15, 0x00 means OK. */
	*smsp = 0x00;

	LOGP(DLSMS, LOGL_INFO, "sending status report for SMS reference %x\n",
	     sms->msg_ref);

	return msg->len - old_msg_len;
}

static int sms_route_mt_sms(struct ran_conn *conn,
			    struct gsm_sms *gsms)
{
	int rc;

#ifdef BUILD_SMPP
	int smpp_first = smpp_route_smpp_first(gsms, conn);

	/*
	 * Route through SMPP first before going to the local database. In case
	 * of a unroutable message and no local subscriber, SMPP will be tried
	 * twice. In case of an unknown subscriber continue with the normal
	 * delivery of the SMS.
	 */
	if (smpp_first) {
		rc = smpp_try_deliver(gsms, conn);
		if (rc == GSM411_RP_CAUSE_MO_NUM_UNASSIGNED)
			/* unknown subscriber, try local */
			goto try_local;
		if (rc < 0) {
	 		LOGP(DLSMS, LOGL_ERROR, "%s: SMS delivery error: %d.",
			     vlr_subscr_name(conn->vsub), rc);
	 		rc = GSM411_RP_CAUSE_MO_TEMP_FAIL;
			/* rc will be logged by gsm411_send_rp_error() */
			rate_ctr_inc(&conn->network->msc_ctrs->ctr[
					MSC_CTR_SMS_DELIVER_UNKNOWN_ERROR]);
		}
		return rc;
	}

try_local:
#endif

	/* determine gsms->receiver based on dialled number */
	gsms->receiver = vlr_subscr_find_by_msisdn(conn->network->vlr, gsms->dst.addr, VSUB_USE_SMS_RECEIVER);
	if (!gsms->receiver) {
#ifdef BUILD_SMPP
		/* Avoid a second look-up */
		if (smpp_first) {
			rate_ctr_inc(&conn->network->msc_ctrs->ctr[MSC_CTR_SMS_NO_RECEIVER]);
			return GSM411_RP_CAUSE_MO_NUM_UNASSIGNED;
		}

		rc = smpp_try_deliver(gsms, conn);
		if (rc == GSM411_RP_CAUSE_MO_NUM_UNASSIGNED) {
			rate_ctr_inc(&conn->network->msc_ctrs->ctr[MSC_CTR_SMS_NO_RECEIVER]);
		} else if (rc < 0) {
	 		LOGP(DLSMS, LOGL_ERROR, "%s: SMS delivery error: %d.",
			     vlr_subscr_name(conn->vsub), rc);
	 		rc = GSM411_RP_CAUSE_MO_TEMP_FAIL;
			/* rc will be logged by gsm411_send_rp_error() */
			rate_ctr_inc(&conn->network->msc_ctrs->ctr[
					MSC_CTR_SMS_DELIVER_UNKNOWN_ERROR]);
		}
#else
		rc = GSM411_RP_CAUSE_MO_NUM_UNASSIGNED;
		rate_ctr_inc(&conn->network->msc_ctrs->ctr[MSC_CTR_SMS_NO_RECEIVER]);
#endif
	} else
		rc = 0;

	return rc;
}


/* process an incoming TPDU (called from RP-DATA)
 * return value > 0: RP CAUSE for ERROR; < 0: silent error; 0 = success */
static int gsm340_rx_tpdu(struct gsm_trans *trans, struct msgb *msg,
			  uint32_t gsm411_msg_ref)
{
	struct ran_conn *conn = trans->conn;
	uint8_t *smsp = msgb_sms(msg);
	struct gsm_sms *gsms;
	unsigned int sms_alphabet;
	uint8_t sms_mti, sms_vpf;
	uint8_t *sms_vp;
	uint8_t da_len_bytes;
	uint8_t address_lv[12]; /* according to 03.40 / 9.1.2.5 */
	int rc = 0;

	rate_ctr_inc(&conn->network->msc_ctrs->ctr[MSC_CTR_SMS_SUBMITTED]);

	gsms = sms_alloc();
	if (!gsms)
		return GSM411_RP_CAUSE_MO_NET_OUT_OF_ORDER;

	/* invert those fields where 0 means active/present */
	sms_mti = *smsp & 0x03;
	sms_vpf = (*smsp & 0x18) >> 3;
	gsms->status_rep_req = (*smsp & 0x20) >> 5;
	gsms->ud_hdr_ind = (*smsp & 0x40);
	/*
	 * Not evaluating MMS (More Messages to Send) because the
	 * lchan stays open anyway.
	 * Not evaluating RP (Reply Path) because we're not aware of its
	 * benefits.
	 */

	smsp++;
	gsms->msg_ref = *smsp++;

	gsms->gsm411.transaction_id = trans->transaction_id;
	gsms->gsm411.msg_ref = gsm411_msg_ref;

	/* length in bytes of the destination address */
	da_len_bytes = 2 + *smsp/2 + *smsp%2;
	if (da_len_bytes > 12) {
		LOGP(DLSMS, LOGL_ERROR, "Destination Address > 12 bytes ?!?\n");
		rc = GSM411_RP_CAUSE_SEMANT_INC_MSG;
		goto out;
	} else if (da_len_bytes < 4) {
		LOGP(DLSMS, LOGL_ERROR, "Destination Address < 4 bytes ?!?\n");
		rc = GSM411_RP_CAUSE_SEMANT_INC_MSG;
		goto out;
	}
	memset(address_lv, 0, sizeof(address_lv));
	memcpy(address_lv, smsp, da_len_bytes);
	/* mangle first byte to reflect length in bytes, not digits */
	address_lv[0] = da_len_bytes - 1;

	gsms->dst.ton = (address_lv[1] >> 4) & 7;
	gsms->dst.npi = address_lv[1] & 0xF;
	/* convert to real number */
	gsm48_decode_bcd_number(gsms->dst.addr,
				sizeof(gsms->dst.addr), address_lv, 1);
	smsp += da_len_bytes;

	gsms->protocol_id = *smsp++;
	gsms->data_coding_scheme = *smsp++;

	sms_alphabet = gsm338_get_sms_alphabet(gsms->data_coding_scheme);
	if (sms_alphabet == 0xffffffff) {
		rc = GSM411_RP_CAUSE_MO_NET_OUT_OF_ORDER;
		goto out;
	}

	switch (sms_vpf) {
	case GSM340_TP_VPF_RELATIVE:
		sms_vp = smsp++;
		break;
	case GSM340_TP_VPF_ABSOLUTE:
	case GSM340_TP_VPF_ENHANCED:
		sms_vp = smsp;
		/* the additional functionality indicator... */
		if (sms_vpf == GSM340_TP_VPF_ENHANCED && *smsp & (1<<7))
			smsp++;
		smsp += 7;
		break;
	case GSM340_TP_VPF_NONE:
		sms_vp = 0;
		break;
	default:
		LOGP(DLSMS, LOGL_NOTICE,
		     "SMS Validity period not implemented: 0x%02x\n", sms_vpf);
		rc = GSM411_RP_CAUSE_MO_NET_OUT_OF_ORDER;
		goto out;
	}
	gsms->user_data_len = *smsp++;
	if (gsms->user_data_len) {
		memcpy(gsms->user_data, smsp, gsms->user_data_len);

		switch (sms_alphabet) {
		case DCS_7BIT_DEFAULT:
			gsm_7bit_decode_n(gsms->text, sizeof(gsms->text), smsp,
					  gsms->user_data_len);
			break;
		case DCS_8BIT_DATA:
		case DCS_UCS2:
		case DCS_NONE:
			break;
		}
	}

	OSMO_STRLCPY_ARRAY(gsms->src.addr, conn->vsub->msisdn);

	LOGP(DLSMS, LOGL_INFO, "RX SMS: Sender: %s, MTI: 0x%02x, VPF: 0x%02x, "
	     "MR: 0x%02x PID: 0x%02x, DCS: 0x%02x, DA: %s, "
	     "UserDataLength: 0x%02x, UserData: \"%s\"\n",
	     vlr_subscr_name(conn->vsub), sms_mti, sms_vpf, gsms->msg_ref,
	     gsms->protocol_id, gsms->data_coding_scheme, gsms->dst.addr,
	     gsms->user_data_len,
			sms_alphabet == DCS_7BIT_DEFAULT ? gsms->text :
				osmo_hexdump(gsms->user_data, gsms->user_data_len));

	gsms->validity_minutes = gsm340_validity_period(sms_vpf, sms_vp);

	/* FIXME: This looks very wrong */
	send_signal(0, NULL, gsms, 0);

	rc = sms_route_mt_sms(conn, gsms);

	/*
	 * This SMS got routed through SMPP or no receiver exists.
	 * In any case, we store it in the database for further processing.
	 */

	switch (sms_mti) {
	case GSM340_SMS_SUBMIT_MS2SC:
		/* MS is submitting a SMS */
		rc = gsm340_rx_sms_submit(gsms);
		break;
	case GSM340_SMS_COMMAND_MS2SC:
	case GSM340_SMS_DELIVER_REP_MS2SC:
		LOGP(DLSMS, LOGL_NOTICE, "Unimplemented MTI 0x%02x\n", sms_mti);
		rc = GSM411_RP_CAUSE_IE_NOTEXIST;
		break;
	default:
		LOGP(DLSMS, LOGL_NOTICE, "Undefined MTI 0x%02x\n", sms_mti);
		rc = GSM411_RP_CAUSE_IE_NOTEXIST;
		break;
	}
out:
	sms_free(gsms);

	return rc;
}

/* Prefix msg with a RP-DATA header and send as SMR DATA */
static int gsm411_rp_sendmsg(struct gsm411_smr_inst *inst, struct msgb *msg,
			     uint8_t rp_msg_type, uint8_t rp_msg_ref,
			     int rl_msg_type)
{
	struct gsm411_rp_hdr *rp;
	uint8_t len = msg->len;

	/* GSM 04.11 RP-DATA header */
	rp = (struct gsm411_rp_hdr *)msgb_push(msg, sizeof(*rp));
	rp->len = len + 2;
	rp->msg_type = rp_msg_type;
	rp->msg_ref = rp_msg_ref;

	return gsm411_smr_send(inst, rl_msg_type, msg);
}

int gsm411_send_rp_ack(struct gsm_trans *trans, uint8_t msg_ref)
{
	struct msgb *msg = gsm411_msgb_alloc();

	DEBUGP(DLSMS, "TX: SMS RP ACK\n");

	return gsm411_rp_sendmsg(&trans->sms.smr_inst, msg, GSM411_MT_RP_ACK_MT,
		msg_ref, GSM411_SM_RL_REPORT_REQ);
}

int gsm411_send_rp_error(struct gsm_trans *trans, uint8_t msg_ref,
			 uint8_t cause)
{
	struct msgb *msg = gsm411_msgb_alloc();

	msgb_tv_put(msg, 1, cause);

	LOGP(DLSMS, LOGL_NOTICE, "TX: SMS RP ERROR, cause %d (%s)\n", cause,
		get_value_string(gsm411_rp_cause_strs, cause));

	return gsm411_rp_sendmsg(&trans->sms.smr_inst, msg,
		GSM411_MT_RP_ERROR_MT, msg_ref, GSM411_SM_RL_REPORT_REQ);
}

/* Receive a 04.11 TPDU inside RP-DATA / user data */
static int gsm411_rx_rp_ud(struct msgb *msg, struct gsm_trans *trans,
			  struct gsm411_rp_hdr *rph,
			  uint8_t *dst, uint8_t dst_len)
{
	int rc = 0;

	if (trans->net->sms_over_gsup) {
		/* RP-ACK or RP-ERROR is triggered as soon as we get the response */
		rc = gsm411_gsup_mo_fwd_sm_req(trans, msg, rph->msg_ref, dst, dst_len);
		if (rc) /* GSUP message sending error */
			return gsm411_send_rp_error(trans, rph->msg_ref, rc);

		return 0;
	}

	rc = gsm340_rx_tpdu(trans, msg, rph->msg_ref);
	if (rc == 0)
		return gsm411_send_rp_ack(trans, rph->msg_ref);