openbsc/src/gprs/sgsn_iu.c - openbsc - Gitiles

 #include <stdint.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>

 #include <osmocom/core/select.h>
 #include <osmocom/core/prim.h>
 #include <osmocom/core/talloc.h>
 #include <osmocom/core/logging.h>
 #include <osmocom/core/application.h>
 #include <osmocom/vty/logging.h>

 #include <osmocom/gsm/gsm48.h>
 #include <osmocom/gprs/gprs_msgb.h>

 #include <osmocom/sigtran/sua.h>
 #include <osmocom/sigtran/sccp_sap.h>

 #include <openbsc/gprs_sgsn.h>
 #include <openbsc/debug.h>

 #include <pdp.h>

 #include <osmocom/ranap/ranap_ies_defs.h>
 #include <osmocom/ranap/ranap_common_cn.h>

 int asn1_xer_print = 1;
 void *talloc_asn1_ctx;

 struct ue_conn_ctx {
 	struct llist_head list;
 	struct osmo_sua_link *link;
 	uint32_t conn_id;
 };

 static LLIST_HEAD(conn_ctx_list);

 struct ue_conn_ctx *ue_conn_ctx_alloc(struct osmo_sua_link *link, uint32_t conn_id)
 {
 	struct ue_conn_ctx *ctx = talloc_zero(NULL, struct ue_conn_ctx);

 	ctx->link = link;
 	ctx->conn_id = conn_id;
 	llist_add(&ctx->list, &conn_ctx_list);

 	return ctx;
 }

 struct ue_conn_ctx *ue_conn_ctx_find(struct osmo_sua_link *link, uint32_t conn_id)
 {
 	struct ue_conn_ctx *ctx;

 	llist_for_each_entry(ctx, &conn_ctx_list, list) {
 		if (ctx->link == link && ctx->conn_id == conn_id)
 			return ctx;
 	}
 	return NULL;
 }

 /***********************************************************************
  * RANAP handling
  ***********************************************************************/

 int gprs_iu_rab_act(struct sgsn_pdp_ctx *pdp)
 {
 	struct sgsn_mm_ctx *mm = pdp->mm;
 	struct ue_conn_ctx *uectx;
 	struct osmo_scu_prim *prim;
 	struct msgb *msg;
 	uint32_t ggsn_ip;

 	uectx = mm->iu.ue_ctx;

 	/* Get the IP address for ggsn user plane */
 	memcpy(&ggsn_ip, pdp->lib->gsnru.v, pdp->lib->gsnru.l);
 	ggsn_ip = htonl(ggsn_ip);

 	msg = ranap_new_msg_rab_assign_data(1, ggsn_ip, pdp->lib->teid_own);
 	msg->l2h = msg->data;

 	/* wrap RANAP message in SCCP N-DATA.req */
 	prim = (struct osmo_scu_prim *) msgb_push(msg, sizeof(*prim));
 	prim->u.data.conn_id = uectx->conn_id;
 	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
 			OSMO_SCU_PRIM_N_DATA,
 			PRIM_OP_REQUEST, msg);
 	osmo_sua_user_link_down(uectx->link, &prim->oph);
 }

 int gprs_iu_rab_deact(struct sgsn_mm_ctx *mm)
 {

 }

 int gprs_transp_upd_key(struct sgsn_mm_ctx *mm)
 {
 	struct gsm_auth_tuple *tp = &mm->auth_triplet;

 	if (mm->ran_type == MM_CTX_T_UTRAN_Iu) {
 		struct ue_conn_ctx *uectx;
 		struct osmo_scu_prim *prim;
 		struct msgb *msg;
 		uint8_t ik[16];
 		uint8_t ck[16];
 		unsigned int i;

 		uectx = mm->iu.ue_ctx;

 		/* C4 function to dervie CK from Kc */
 		memcpy(ck, tp->kc, 8);
 		memcpy(ck+8, tp->kc, 8);

 		/* C5 function to derive IK from Kc */
 		for (i = 0; i < 4; i++)
 			ik[i] = tp->kc[i] ^ tp->kc[i+4];
 		memcpy(ik+4, tp->kc, 8);
 		for (i = 12; i < 16; i++)
 			ik[i] = ik[i-12];

 		/* crate RANAP message */
 		msg = ranap_new_msg_sec_mod_cmd(ik, NULL);
 		msg->l2h = msg->data;
 		/* wrap RANAP message in SCCP N-DATA.req */
 		prim = (struct osmo_scu_prim *) msgb_push(msg, sizeof(*prim));
 		prim->u.data.conn_id = uectx->conn_id;
 		osmo_prim_init(&prim->oph, SCCP_SAP_USER,
 				OSMO_SCU_PRIM_N_DATA,
 				PRIM_OP_REQUEST, msg);
 		osmo_sua_user_link_down(uectx->link, &prim->oph);
 	}

 	return 0;
 }

 static int ranap_handle_co_initial_ue(void *ctx, RANAP_InitialUE_MessageIEs_t *ies)
 {
 	struct gprs_ra_id ra_id;
 	uint16_t sai;
 	struct msgb *msg = msgb_alloc(256, "RANAP->NAS");

 	ranap_parse_lai(&ra_id, &ies->lai);
 	sai = asn1str_to_u16(&ies->sai.sAC);
 	msgb_gmmh(msg) = msgb_put(msg, ies->nas_pdu.size);
 	memcpy(msgb_gmmh(msg), ies->nas_pdu.buf, ies->nas_pdu.size);

 	/* Feed into the MM layer */
 	msg->dst = ctx;
 	gsm0408_gprs_rcvmsg_iu(msg, ra_id, sai);

 	return 0;
 }

 static int ranap_handle_co_dt(void *ctx, RANAP_DirectTransferIEs_t *ies)
 {
 	struct gprs_ra_id _ra_id, *ra_id = NULL;
 	uint16_t _sai, *sai = NULL;
 	struct msgb *msg = msgb_alloc(256, "RANAP->NAS");

 	if (ies->presenceMask & DIRECTTRANSFERIES_RANAP_LAI_PRESENT) {
 		ranap_parse_lai(&_ra_id, &ies->lai);
 		ra_id = &_ra_id;
 		if (ies->presenceMask & DIRECTTRANSFERIES_RANAP_RAC_PRESENT) {
 			_ra_id.rac = asn1str_to_u8(&ies->rac);
 		}
 		if (ies->presenceMask & DIRECTTRANSFERIES_RANAP_SAI_PRESENT) {
 			_sai = asn1str_to_u16(&ies->sai.sAC);
 			sai = &_sai;
 		}
 	}

 	msgb_gmmh(msg) = msgb_put(msg, ies->nas_pdu.size);
 	memcpy(msgb_gmmh(msg), ies->nas_pdu.buf, ies->nas_pdu.size);

 	/* Feed into the MM/CC/SMS-CP layer */
 	msg->dst = ctx;
 	gsm0408_gprs_rcvmsg_iu(msg, ra_id, sai);

 	return 0;
 }

 static int ranap_handle_co_err_ind(void *ctx, RANAP_ErrorIndicationIEs_t *ies)
 {
 	if (ies->presenceMask & ERRORINDICATIONIES_RANAP_CAUSE_PRESENT)
 		LOGP(DRANAP, LOGL_ERROR, "Rx Error Indication (%s)\n",
 			ranap_cause_str(&ies->cause));
 	else
 		LOGP(DRANAP, LOGL_ERROR, "Rx Error Indication\n");

 	return 0;
 }

 int gprs_iu_tx(struct msgb *msg, uint8_t sapi, struct mm_context *mm)
 {
 	struct ue_conn_ctx *uectx = msg->dst;
 	struct osmo_scu_prim *prim;

 	LOGP(DRANAP, LOGL_INFO, "Transmitting L3 Message as RANAP DT\n");

 	msg = ranap_new_msg_dt(sapi, msg->data, msgb_length(msg));
 	msg->l2h = msg->data;
 	prim = (struct osmo_scu_prim *) msgb_push(msg, sizeof(*prim));
 	prim->u.data.conn_id = uectx->conn_id;
 	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
 			OSMO_SCU_PRIM_N_DATA,
 			PRIM_OP_REQUEST, msg);
 	osmo_sua_user_link_down(uectx->link, &prim->oph);
 	return 0;
 }

 static int ranap_handle_co_iu_rel_req(struct ue_conn_ctx *ctx, RANAP_Iu_ReleaseRequestIEs_t *ies)
 {
 	struct msgb *msg;
 	struct osmo_scu_prim *prim;

 	LOGP(DRANAP, LOGL_INFO, "Received Iu Release Request, Sending Release Command\n");
 	msg = ranap_new_msg_iu_rel_cmd(&ies->cause);
 	msg->l2h = msg->data;
 	prim = (struct osmo_scu_prim *) msgb_push(msg, sizeof(*prim));
 	prim->u.data.conn_id = ctx->conn_id;
 	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
 			OSMO_SCU_PRIM_N_DATA,
 			PRIM_OP_REQUEST, msg);
 	osmo_sua_user_link_down(ctx->link, &prim->oph);
 	return 0;
 }

 int send_act_pdp_cont_acc(struct sgsn_pdp_ctx *pctx);

 static int ranap_handle_co_rab_ass_resp(struct ue_conn_ctx *ctx, RANAP_RAB_AssignmentResponseIEs_t *ies)
 {
 	struct sgsn_mm_ctx *mm;
 	struct sgsn_pdp_ctx *pdp = NULL;
 	int i, rc;
 	uint8_t rab_id;
 	uint32_t gtp_tei;

 	mm = sgsn_mm_ctx_by_ue_ctx(ctx);
 	/* XXX: Error handling */

 	LOGP(DRANAP, LOGL_INFO, "RAB Asignment Response:");
 	if (ies->presenceMask & RAB_ASSIGNMENTRESPONSEIES_RANAP_RAB_SETUPORMODIFIEDLIST_PRESENT) {
 		RANAP_IE_t *ranap_ie = ies->raB_SetupOrModifiedList.raB_SetupOrModifiedList_ies.list.array[0];
 		RANAP_RAB_SetupOrModifiedItemIEs_t setup_ies;
 		RANAP_RAB_SetupOrModifiedItem_t *item = &setup_ies.raB_SetupOrModifiedItem;
 		rc = ranap_decode_rab_setupormodifieditemies(&setup_ies, &ranap_ie->value);

 		rab_id = item->rAB_ID.buf[0];
 		if (item->iuTransportAssociation->present == RANAP_IuTransportAssociation_PR_gTP_TEI) {
 			gtp_tei = asn1str_to_u32(&item->iuTransportAssociation->choice.gTP_TEI);
 			pdp = sgsn_pdp_ctx_by_tei(mm, gtp_tei);
 		}

 		if (!pdp) {
 			ranap_free_rab_setupormodifieditemies(&setup_ies);
 			return -1;
 		}

 		if (item->transportLayerAddress) {

 			LOGPC(DRANAP, LOGL_INFO, " Setup: (%u/%s)", rab_id, osmo_hexdump(item->transportLayerAddress->buf,
 									     item->transportLayerAddress->size));
 			memcpy(pdp->lib->gsnlu.v, &item->transportLayerAddress->buf[3], 4);
 			gtp_update_context(pdp->ggsn->gsn, pdp->lib, pdp, &pdp->lib->hisaddr0);

 		}
 		ranap_free_rab_setupormodifieditemies(&setup_ies);
 	}

 	LOGPC(DRANAP, LOGL_INFO, "\n");

 	send_act_pdp_cont_acc(pdp);

 	return rc;
 }

 /* Entry point for connection-oriented ANAP message */
 static void cn_ranap_handle_co(void *ctx, ranap_message *message)
 {
 	int rc = 0;

 	LOGP(DRANAP, LOGL_NOTICE, "handle_co(dir=%u, proc=%u)\n", message->direction, message->procedureCode);

 	switch (message->direction) {
 	case RANAP_RANAP_PDU_PR_initiatingMessage:
 		switch (message->procedureCode) {
 		case RANAP_ProcedureCode_id_InitialUE_Message:
 			rc = ranap_handle_co_initial_ue(ctx, &message->msg.initialUE_MessageIEs);
 			break;
 		case RANAP_ProcedureCode_id_DirectTransfer:
 			rc = ranap_handle_co_dt(ctx, &message->msg.directTransferIEs);
 			break;
 		case RANAP_ProcedureCode_id_ErrorIndication:
 			rc = ranap_handle_co_err_ind(ctx, &message->msg.errorIndicationIEs);
 			break;
 		case RANAP_ProcedureCode_id_Iu_ReleaseRequest:
 			/* Iu Release Request */
 			rc = ranap_handle_co_iu_rel_req(ctx, &message->msg.iu_ReleaseRequestIEs);
 			break;
 		}
 		break;
 	case RANAP_RANAP_PDU_PR_successfulOutcome:
 		switch (message->procedureCode) {
 		case RANAP_ProcedureCode_id_SecurityModeControl:
 			/* Security Mode Complete */
 			break;
 		case RANAP_ProcedureCode_id_Iu_Release:
 			/* Iu Release Complete */
 			break;
 		}
 	case RANAP_RANAP_PDU_PR_outcome:
 		switch (message->procedureCode) {
 		case RANAP_ProcedureCode_id_RAB_Assignment:
 			/* RAB Assignment Response */
 			rc = ranap_handle_co_rab_ass_resp(ctx, &message->msg.raB_AssignmentResponseIEs);
 			break;
 		}
 	case RANAP_RANAP_PDU_PR_unsuccessfulOutcome:
 	default:
 		rc = -1;
 		break;
 	}
 }

 static int ranap_handle_cl_reset_req(void *ctx, RANAP_ResetIEs_t *ies)
 {
 	/* FIXME: send reset response */
 }

 static int ranap_handle_cl_err_ind(void *ctx, RANAP_ErrorIndicationIEs_t *ies)
 {
 	if (ies->presenceMask & ERRORINDICATIONIES_RANAP_CAUSE_PRESENT)
 		LOGP(DRANAP, LOGL_ERROR, "Rx Error Indication (%s)\n",
 			ranap_cause_str(&ies->cause));
 	else
 		LOGP(DRANAP, LOGL_ERROR, "Rx Error Indication\n");

 	return 0;
 }

 /* Entry point for connection-less RANAP message */
 static void cn_ranap_handle_cl(void *ctx, ranap_message *message)
 {
 	int rc = 0;

 	switch (message->direction) {
 	case RANAP_RANAP_PDU_PR_initiatingMessage:
 		switch (message->procedureCode) {
 		case RANAP_ProcedureCode_id_Reset:
 			/* received reset.req, send reset.resp */
 			rc = ranap_handle_cl_reset_req(ctx, &message->msg.resetIEs);
 			break;
 		case RANAP_ProcedureCode_id_ErrorIndication:
 			rc = ranap_handle_cl_err_ind(ctx, &message->msg.errorIndicationIEs);
 			break;
 		}
 		break;
 	case RANAP_RANAP_PDU_PR_successfulOutcome:
 	case RANAP_RANAP_PDU_PR_unsuccessfulOutcome:
 	case RANAP_RANAP_PDU_PR_outcome:
 	default:
 		rc = -1;
 		break;
 	}
 }

 /***********************************************************************
  *
  ***********************************************************************/

 int tx_unitdata(struct osmo_sua_link *link);
 int tx_conn_req(struct osmo_sua_link *link, uint32_t conn_id);

 struct osmo_prim_hdr *make_conn_req(uint32_t conn_id);
 struct osmo_prim_hdr *make_dt1_req(uint32_t conn_id, const uint8_t *data, unsigned int len);

 struct osmo_prim_hdr *make_conn_resp(struct osmo_scu_connect_param *param)
 {
 	struct msgb *msg = msgb_alloc(1024, "conn_resp");
 	struct osmo_scu_prim *prim;

 	prim = (struct osmo_scu_prim *) msgb_put(msg, sizeof(*prim));
 	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
 			OSMO_SCU_PRIM_N_CONNECT,
 			PRIM_OP_RESPONSE, msg);
 	memcpy(&prim->u.connect, param, sizeof(prim->u.connect));
 	return &prim->oph;
 }

 static int sccp_sap_up(struct osmo_prim_hdr *oph, void *link)
 {
 	struct osmo_scu_prim *prim = (struct osmo_scu_prim *) oph;
 	struct osmo_prim_hdr *resp = NULL;
 	const uint8_t payload[] = { 0xb1, 0xb2, 0xb3 };
 	int rc;
 	struct ue_conn_ctx *ue;

 	printf("sccp_sap_up(%s)\n", osmo_scu_prim_name(oph));

 	switch (OSMO_PRIM_HDR(oph)) {
 	case OSMO_PRIM(OSMO_SCU_PRIM_N_CONNECT, PRIM_OP_CONFIRM):
 		/* confirmation of outbound connection */
 		break;
 	case OSMO_PRIM(OSMO_SCU_PRIM_N_CONNECT, PRIM_OP_INDICATION):
 		/* indication of new inbound connection request*/
 		printf("N-CONNECT.ind(X->%u)\n", prim->u.connect.conn_id);
 		if (/*  prim->u.connect.called_addr.ssn != OSMO_SCCP_SSN_RANAP || */
 		    !msgb_l2(oph->msg) || msgb_l2len(oph->msg) == 0) {
 			LOGP(DGPRS, LOGL_NOTICE, "Received invalid N-CONNECT.ind\n");
 			return 0;
 		}
 		/* allocate UE context */
 		ue = ue_conn_ctx_alloc(link, prim->u.connect.conn_id);
 		/* first ensure the local SUA/SCCP socket is ACTIVE */
 		resp = make_conn_resp(&prim->u.connect);
 		osmo_sua_user_link_down(link, resp);
 		/* then handle the RANAP payload */
 		rc = ranap_cn_rx_co(cn_ranap_handle_co, ue, msgb_l2(oph->msg), msgb_l2len(oph->msg));
 		break;
 	case OSMO_PRIM(OSMO_SCU_PRIM_N_DISCONNECT, PRIM_OP_INDICATION):
 		/* indication of disconnect */
 		printf("N-DISCONNECT.ind(%u)\n", prim->u.disconnect.conn_id);
 		ue = ue_conn_ctx_find(link, prim->u.disconnect.conn_id);
 		rc = ranap_cn_rx_co(cn_ranap_handle_co, ue, msgb_l2(oph->msg), msgb_l2len(oph->msg));
 		break;
 	case OSMO_PRIM(OSMO_SCU_PRIM_N_DATA, PRIM_OP_INDICATION):
 		/* connection-oriented data received */
 		printf("N-DATA.ind(%u, %s)\n", prim->u.data.conn_id,
 			osmo_hexdump(msgb_l2(oph->msg), msgb_l2len(oph->msg)));
 		/* resolve UE context */
 		ue = ue_conn_ctx_find(link, prim->u.data.conn_id);
 		rc = ranap_cn_rx_co(cn_ranap_handle_co, ue, msgb_l2(oph->msg), msgb_l2len(oph->msg));
 		break;
 	case OSMO_PRIM(OSMO_SCU_PRIM_N_UNITDATA, PRIM_OP_INDICATION):
 		/* connection-less data received */
 		printf("N-UNITDATA.ind(%s)\n",
 			osmo_hexdump(msgb_l2(oph->msg), msgb_l2len(oph->msg)));
 		rc = ranap_cn_rx_cl(cn_ranap_handle_cl, link, msgb_l2(oph->msg), msgb_l2len(oph->msg));
 		break;
 	}

 	msgb_free(oph->msg);
 	return 0;
 }

 int sgsn_iu_init(void *ctx)
 {
 	struct osmo_sua_user *user;
 	int rc;

 	talloc_asn1_ctx = talloc_named_const(ctx, 1, "asn1");

 	osmo_sua_set_log_area(DSUA);

 	user = osmo_sua_user_create(ctx, sccp_sap_up, ctx);

 	rc = osmo_sua_server_listen(user, "127.0.0.2", 14001);
 	if (rc < 0) {
 		exit(1);
 	}
 }
	#include <stdint.h>
	#include <unistd.h>
	#include <stdlib.h>
	#include <stdio.h>
	#include <string.h>

	#include <osmocom/core/select.h>
	#include <osmocom/core/prim.h>
	#include <osmocom/core/talloc.h>
	#include <osmocom/core/logging.h>
	#include <osmocom/core/application.h>
	#include <osmocom/vty/logging.h>

	#include <osmocom/gsm/gsm48.h>
	#include <osmocom/gprs/gprs_msgb.h>

	#include <osmocom/sigtran/sua.h>
	#include <osmocom/sigtran/sccp_sap.h>

	#include <openbsc/gprs_sgsn.h>
	#include <openbsc/debug.h>

	#include <pdp.h>

	#include <osmocom/ranap/ranap_ies_defs.h>
	#include <osmocom/ranap/ranap_common_cn.h>

	int asn1_xer_print = 1;
	void *talloc_asn1_ctx;

	struct ue_conn_ctx {
	struct llist_head list;
	struct osmo_sua_link *link;
	uint32_t conn_id;
	};

	static LLIST_HEAD(conn_ctx_list);

	struct ue_conn_ctx ue_conn_ctx_alloc(struct osmo_sua_link link, uint32_t conn_id)
	{
	struct ue_conn_ctx *ctx = talloc_zero(NULL, struct ue_conn_ctx);

	ctx->link = link;
	ctx->conn_id = conn_id;
	llist_add(&ctx->list, &conn_ctx_list);

	return ctx;
	}

	struct ue_conn_ctx ue_conn_ctx_find(struct osmo_sua_link link, uint32_t conn_id)
	{
	struct ue_conn_ctx *ctx;

	llist_for_each_entry(ctx, &conn_ctx_list, list) {
	if (ctx->link == link && ctx->conn_id == conn_id)
	return ctx;
	}
	return NULL;
	}

	/***********************************************************************
	* RANAP handling
	***********************************************************************/

	int gprs_iu_rab_act(struct sgsn_pdp_ctx *pdp)
	{
	struct sgsn_mm_ctx *mm = pdp->mm;
	struct ue_conn_ctx *uectx;
	struct osmo_scu_prim *prim;
	struct msgb *msg;
	uint32_t ggsn_ip;

	uectx = mm->iu.ue_ctx;

	/* Get the IP address for ggsn user plane */
	memcpy(&ggsn_ip, pdp->lib->gsnru.v, pdp->lib->gsnru.l);
	ggsn_ip = htonl(ggsn_ip);

	msg = ranap_new_msg_rab_assign_data(1, ggsn_ip, pdp->lib->teid_own);
	msg->l2h = msg->data;

	/* wrap RANAP message in SCCP N-DATA.req */
	prim = (struct osmo_scu_prim ) msgb_push(msg, sizeof(prim));
	prim->u.data.conn_id = uectx->conn_id;
	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
	OSMO_SCU_PRIM_N_DATA,
	PRIM_OP_REQUEST, msg);
	osmo_sua_user_link_down(uectx->link, &prim->oph);
	}

	int gprs_iu_rab_deact(struct sgsn_mm_ctx *mm)
	{

	}

	int gprs_transp_upd_key(struct sgsn_mm_ctx *mm)
	{
	struct gsm_auth_tuple *tp = &mm->auth_triplet;

	if (mm->ran_type == MM_CTX_T_UTRAN_Iu) {
	struct ue_conn_ctx *uectx;
	struct osmo_scu_prim *prim;
	struct msgb *msg;
	uint8_t ik[16];
	uint8_t ck[16];
	unsigned int i;

	uectx = mm->iu.ue_ctx;

	/* C4 function to dervie CK from Kc */
	memcpy(ck, tp->kc, 8);
	memcpy(ck+8, tp->kc, 8);

	/* C5 function to derive IK from Kc */
	for (i = 0; i < 4; i++)
	ik[i] = tp->kc[i] ^ tp->kc[i+4];
	memcpy(ik+4, tp->kc, 8);
	for (i = 12; i < 16; i++)
	ik[i] = ik[i-12];

	/* crate RANAP message */
	msg = ranap_new_msg_sec_mod_cmd(ik, NULL);
	msg->l2h = msg->data;
	/* wrap RANAP message in SCCP N-DATA.req */
	prim = (struct osmo_scu_prim ) msgb_push(msg, sizeof(prim));
	prim->u.data.conn_id = uectx->conn_id;
	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
	OSMO_SCU_PRIM_N_DATA,
	PRIM_OP_REQUEST, msg);
	osmo_sua_user_link_down(uectx->link, &prim->oph);
	}

	return 0;
	}

	static int ranap_handle_co_initial_ue(void ctx, RANAP_InitialUE_MessageIEs_t ies)
	{
	struct gprs_ra_id ra_id;
	uint16_t sai;
	struct msgb *msg = msgb_alloc(256, "RANAP->NAS");

	ranap_parse_lai(&ra_id, &ies->lai);
	sai = asn1str_to_u16(&ies->sai.sAC);
	msgb_gmmh(msg) = msgb_put(msg, ies->nas_pdu.size);
	memcpy(msgb_gmmh(msg), ies->nas_pdu.buf, ies->nas_pdu.size);

	/* Feed into the MM layer */
	msg->dst = ctx;
	gsm0408_gprs_rcvmsg_iu(msg, ra_id, sai);

	return 0;
	}

	static int ranap_handle_co_dt(void ctx, RANAP_DirectTransferIEs_t ies)
	{
	struct gprs_ra_id _ra_id, *ra_id = NULL;
	uint16_t _sai, *sai = NULL;
	struct msgb *msg = msgb_alloc(256, "RANAP->NAS");

	if (ies->presenceMask & DIRECTTRANSFERIES_RANAP_LAI_PRESENT) {
	ranap_parse_lai(&_ra_id, &ies->lai);
	ra_id = &_ra_id;
	if (ies->presenceMask & DIRECTTRANSFERIES_RANAP_RAC_PRESENT) {
	_ra_id.rac = asn1str_to_u8(&ies->rac);
	}
	if (ies->presenceMask & DIRECTTRANSFERIES_RANAP_SAI_PRESENT) {
	_sai = asn1str_to_u16(&ies->sai.sAC);
	sai = &_sai;
	}
	}

	msgb_gmmh(msg) = msgb_put(msg, ies->nas_pdu.size);
	memcpy(msgb_gmmh(msg), ies->nas_pdu.buf, ies->nas_pdu.size);

	/* Feed into the MM/CC/SMS-CP layer */
	msg->dst = ctx;
	gsm0408_gprs_rcvmsg_iu(msg, ra_id, sai);

	return 0;
	}

	static int ranap_handle_co_err_ind(void ctx, RANAP_ErrorIndicationIEs_t ies)
	{
	if (ies->presenceMask & ERRORINDICATIONIES_RANAP_CAUSE_PRESENT)
	LOGP(DRANAP, LOGL_ERROR, "Rx Error Indication (%s)\n",
	ranap_cause_str(&ies->cause));
	else
	LOGP(DRANAP, LOGL_ERROR, "Rx Error Indication\n");

	return 0;
	}

	int gprs_iu_tx(struct msgb msg, uint8_t sapi, struct mm_context mm)
	{
	struct ue_conn_ctx *uectx = msg->dst;
	struct osmo_scu_prim *prim;

	LOGP(DRANAP, LOGL_INFO, "Transmitting L3 Message as RANAP DT\n");

	msg = ranap_new_msg_dt(sapi, msg->data, msgb_length(msg));
	msg->l2h = msg->data;
	prim = (struct osmo_scu_prim ) msgb_push(msg, sizeof(prim));
	prim->u.data.conn_id = uectx->conn_id;
	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
	OSMO_SCU_PRIM_N_DATA,
	PRIM_OP_REQUEST, msg);
	osmo_sua_user_link_down(uectx->link, &prim->oph);
	return 0;
	}

	static int ranap_handle_co_iu_rel_req(struct ue_conn_ctx ctx, RANAP_Iu_ReleaseRequestIEs_t ies)
	{
	struct msgb *msg;
	struct osmo_scu_prim *prim;

	LOGP(DRANAP, LOGL_INFO, "Received Iu Release Request, Sending Release Command\n");
	msg = ranap_new_msg_iu_rel_cmd(&ies->cause);
	msg->l2h = msg->data;
	prim = (struct osmo_scu_prim ) msgb_push(msg, sizeof(prim));
	prim->u.data.conn_id = ctx->conn_id;
	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
	OSMO_SCU_PRIM_N_DATA,
	PRIM_OP_REQUEST, msg);
	osmo_sua_user_link_down(ctx->link, &prim->oph);
	return 0;
	}

	int send_act_pdp_cont_acc(struct sgsn_pdp_ctx *pctx);

	static int ranap_handle_co_rab_ass_resp(struct ue_conn_ctx ctx, RANAP_RAB_AssignmentResponseIEs_t ies)
	{
	struct sgsn_mm_ctx *mm;
	struct sgsn_pdp_ctx *pdp = NULL;
	int i, rc;
	uint8_t rab_id;
	uint32_t gtp_tei;

	mm = sgsn_mm_ctx_by_ue_ctx(ctx);
	/* XXX: Error handling */

	LOGP(DRANAP, LOGL_INFO, "RAB Asignment Response:");
	if (ies->presenceMask & RAB_ASSIGNMENTRESPONSEIES_RANAP_RAB_SETUPORMODIFIEDLIST_PRESENT) {
	RANAP_IE_t *ranap_ie = ies->raB_SetupOrModifiedList.raB_SetupOrModifiedList_ies.list.array[0];
	RANAP_RAB_SetupOrModifiedItemIEs_t setup_ies;
	RANAP_RAB_SetupOrModifiedItem_t *item = &setup_ies.raB_SetupOrModifiedItem;
	rc = ranap_decode_rab_setupormodifieditemies(&setup_ies, &ranap_ie->value);

	rab_id = item->rAB_ID.buf[0];
	if (item->iuTransportAssociation->present == RANAP_IuTransportAssociation_PR_gTP_TEI) {
	gtp_tei = asn1str_to_u32(&item->iuTransportAssociation->choice.gTP_TEI);
	pdp = sgsn_pdp_ctx_by_tei(mm, gtp_tei);
	}

	if (!pdp) {
	ranap_free_rab_setupormodifieditemies(&setup_ies);
	return -1;
	}

	if (item->transportLayerAddress) {

	LOGPC(DRANAP, LOGL_INFO, " Setup: (%u/%s)", rab_id, osmo_hexdump(item->transportLayerAddress->buf,
	item->transportLayerAddress->size));
	memcpy(pdp->lib->gsnlu.v, &item->transportLayerAddress->buf[3], 4);
	gtp_update_context(pdp->ggsn->gsn, pdp->lib, pdp, &pdp->lib->hisaddr0);

	}
	ranap_free_rab_setupormodifieditemies(&setup_ies);
	}

	LOGPC(DRANAP, LOGL_INFO, "\n");

	send_act_pdp_cont_acc(pdp);

	return rc;
	}

	/* Entry point for connection-oriented ANAP message */
	static void cn_ranap_handle_co(void ctx, ranap_message message)
	{
	int rc = 0;

	LOGP(DRANAP, LOGL_NOTICE, "handle_co(dir=%u, proc=%u)\n", message->direction, message->procedureCode);

	switch (message->direction) {
	case RANAP_RANAP_PDU_PR_initiatingMessage:
	switch (message->procedureCode) {
	case RANAP_ProcedureCode_id_InitialUE_Message:
	rc = ranap_handle_co_initial_ue(ctx, &message->msg.initialUE_MessageIEs);
	break;
	case RANAP_ProcedureCode_id_DirectTransfer:
	rc = ranap_handle_co_dt(ctx, &message->msg.directTransferIEs);
	break;
	case RANAP_ProcedureCode_id_ErrorIndication:
	rc = ranap_handle_co_err_ind(ctx, &message->msg.errorIndicationIEs);
	break;
	case RANAP_ProcedureCode_id_Iu_ReleaseRequest:
	/* Iu Release Request */
	rc = ranap_handle_co_iu_rel_req(ctx, &message->msg.iu_ReleaseRequestIEs);
	break;
	}
	break;
	case RANAP_RANAP_PDU_PR_successfulOutcome:
	switch (message->procedureCode) {
	case RANAP_ProcedureCode_id_SecurityModeControl:
	/* Security Mode Complete */
	break;
	case RANAP_ProcedureCode_id_Iu_Release:
	/* Iu Release Complete */
	break;
	}
	case RANAP_RANAP_PDU_PR_outcome:
	switch (message->procedureCode) {
	case RANAP_ProcedureCode_id_RAB_Assignment:
	/* RAB Assignment Response */
	rc = ranap_handle_co_rab_ass_resp(ctx, &message->msg.raB_AssignmentResponseIEs);
	break;
	}
	case RANAP_RANAP_PDU_PR_unsuccessfulOutcome:
	default:
	rc = -1;
	break;
	}
	}

	static int ranap_handle_cl_reset_req(void ctx, RANAP_ResetIEs_t ies)
	{
	/* FIXME: send reset response */
	}

	static int ranap_handle_cl_err_ind(void ctx, RANAP_ErrorIndicationIEs_t ies)
	{
	if (ies->presenceMask & ERRORINDICATIONIES_RANAP_CAUSE_PRESENT)
	LOGP(DRANAP, LOGL_ERROR, "Rx Error Indication (%s)\n",
	ranap_cause_str(&ies->cause));
	else
	LOGP(DRANAP, LOGL_ERROR, "Rx Error Indication\n");

	return 0;
	}

	/* Entry point for connection-less RANAP message */
	static void cn_ranap_handle_cl(void ctx, ranap_message message)
	{
	int rc = 0;

	switch (message->direction) {
	case RANAP_RANAP_PDU_PR_initiatingMessage:
	switch (message->procedureCode) {
	case RANAP_ProcedureCode_id_Reset:
	/* received reset.req, send reset.resp */
	rc = ranap_handle_cl_reset_req(ctx, &message->msg.resetIEs);
	break;
	case RANAP_ProcedureCode_id_ErrorIndication:
	rc = ranap_handle_cl_err_ind(ctx, &message->msg.errorIndicationIEs);
	break;
	}
	break;
	case RANAP_RANAP_PDU_PR_successfulOutcome:
	case RANAP_RANAP_PDU_PR_unsuccessfulOutcome:
	case RANAP_RANAP_PDU_PR_outcome:
	default:
	rc = -1;
	break;
	}
	}

	/***********************************************************************
	*
	***********************************************************************/

	int tx_unitdata(struct osmo_sua_link *link);
	int tx_conn_req(struct osmo_sua_link *link, uint32_t conn_id);

	struct osmo_prim_hdr *make_conn_req(uint32_t conn_id);
	struct osmo_prim_hdr make_dt1_req(uint32_t conn_id, const uint8_t data, unsigned int len);

	struct osmo_prim_hdr make_conn_resp(struct osmo_scu_connect_param param)
	{
	struct msgb *msg = msgb_alloc(1024, "conn_resp");
	struct osmo_scu_prim *prim;

	prim = (struct osmo_scu_prim ) msgb_put(msg, sizeof(prim));
	osmo_prim_init(&prim->oph, SCCP_SAP_USER,
	OSMO_SCU_PRIM_N_CONNECT,
	PRIM_OP_RESPONSE, msg);
	memcpy(&prim->u.connect, param, sizeof(prim->u.connect));
	return &prim->oph;
	}

	static int sccp_sap_up(struct osmo_prim_hdr oph, void link)
	{
	struct osmo_scu_prim prim = (struct osmo_scu_prim ) oph;
	struct osmo_prim_hdr *resp = NULL;
	const uint8_t payload[] = { 0xb1, 0xb2, 0xb3 };
	int rc;
	struct ue_conn_ctx *ue;

	printf("sccp_sap_up(%s)\n", osmo_scu_prim_name(oph));

	switch (OSMO_PRIM_HDR(oph)) {
	case OSMO_PRIM(OSMO_SCU_PRIM_N_CONNECT, PRIM_OP_CONFIRM):
	/* confirmation of outbound connection */
	break;
	case OSMO_PRIM(OSMO_SCU_PRIM_N_CONNECT, PRIM_OP_INDICATION):
	/* indication of new inbound connection request*/
	printf("N-CONNECT.ind(X->%u)\n", prim->u.connect.conn_id);
	if (/* prim->u.connect.called_addr.ssn != OSMO_SCCP_SSN_RANAP \|\| */
	!msgb_l2(oph->msg) \|\| msgb_l2len(oph->msg) == 0) {
	LOGP(DGPRS, LOGL_NOTICE, "Received invalid N-CONNECT.ind\n");
	return 0;
	}
	/* allocate UE context */
	ue = ue_conn_ctx_alloc(link, prim->u.connect.conn_id);
	/* first ensure the local SUA/SCCP socket is ACTIVE */
	resp = make_conn_resp(&prim->u.connect);
	osmo_sua_user_link_down(link, resp);
	/* then handle the RANAP payload */
	rc = ranap_cn_rx_co(cn_ranap_handle_co, ue, msgb_l2(oph->msg), msgb_l2len(oph->msg));
	break;
	case OSMO_PRIM(OSMO_SCU_PRIM_N_DISCONNECT, PRIM_OP_INDICATION):
	/* indication of disconnect */
	printf("N-DISCONNECT.ind(%u)\n", prim->u.disconnect.conn_id);
	ue = ue_conn_ctx_find(link, prim->u.disconnect.conn_id);
	rc = ranap_cn_rx_co(cn_ranap_handle_co, ue, msgb_l2(oph->msg), msgb_l2len(oph->msg));
	break;
	case OSMO_PRIM(OSMO_SCU_PRIM_N_DATA, PRIM_OP_INDICATION):
	/* connection-oriented data received */
	printf("N-DATA.ind(%u, %s)\n", prim->u.data.conn_id,
	osmo_hexdump(msgb_l2(oph->msg), msgb_l2len(oph->msg)));
	/* resolve UE context */
	ue = ue_conn_ctx_find(link, prim->u.data.conn_id);
	rc = ranap_cn_rx_co(cn_ranap_handle_co, ue, msgb_l2(oph->msg), msgb_l2len(oph->msg));
	break;
	case OSMO_PRIM(OSMO_SCU_PRIM_N_UNITDATA, PRIM_OP_INDICATION):
	/* connection-less data received */
	printf("N-UNITDATA.ind(%s)\n",
	osmo_hexdump(msgb_l2(oph->msg), msgb_l2len(oph->msg)));
	rc = ranap_cn_rx_cl(cn_ranap_handle_cl, link, msgb_l2(oph->msg), msgb_l2len(oph->msg));
	break;
	}

	msgb_free(oph->msg);
	return 0;
	}

	int sgsn_iu_init(void *ctx)
	{
	struct osmo_sua_user *user;
	int rc;

	talloc_asn1_ctx = talloc_named_const(ctx, 1, "asn1");

	osmo_sua_set_log_area(DSUA);

	user = osmo_sua_user_create(ctx, sccp_sap_up, ctx);

	rc = osmo_sua_server_listen(user, "127.0.0.2", 14001);
	if (rc < 0) {
	exit(1);
	}
	}