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#include <inttypes.h>
#include <osmocom/core/logging.h>
#include <openbsc/debug.h>
#include <openbsc/gsm_data.h>
#include <openbsc/iu.h>
#include <openbsc/bsc_api.h> /* for BSC_API_CONN_POL_ACCEPT, TODO move that to libmsc */
#include "../libmsc/msc_api.h"
/* For A-interface see libbsc/bsc_api.c subscr_con_allocate() */
struct gsm_subscriber_connection *subscr_conn_allocate_iu(struct gsm_network *network,
struct ue_conn_ctx *ue)
{
struct gsm_subscriber_connection *conn;
DEBUGP(DIUCS, "Allocating IuCS subscriber conn: link_id %p, conn_id %" PRIx32 "\n",
ue->link, ue->conn_id);
conn = talloc_zero(network, struct gsm_subscriber_connection);
if (!conn)
return NULL;
conn->network = network;
conn->via_iface = IFACE_IU;
conn->iu.ue_ctx = ue;
llist_add_tail(&conn->entry, &network->subscr_conns);
return conn;
}
static int same_ue_conn(struct ue_conn_ctx *a, struct ue_conn_ctx *b)
{
if (a == b)
return 1;
return (a->link == b->link)
&& (a->conn_id != b->conn_id);
}
/* Return an existing IuCS subscriber connection record for the given link and
* connection IDs, or return NULL if not found. */
static struct gsm_subscriber_connection *subscr_conn_lookup_iu(struct gsm_network *network,
struct ue_conn_ctx *ue)
{
struct gsm_subscriber_connection *conn;
llist_for_each_entry(conn, &network->subscr_conns, entry) {
if (conn->via_iface != IFACE_IU)
continue;
if (!same_ue_conn(conn->iu.ue_ctx, ue))
continue;
DEBUGP(DIUCS, "Found IuCS subscriber for link_id %p, conn_id %" PRIx32 "\n",
ue->link, ue->conn_id);
return conn;
}
DEBUGP(DIUCS, "No IuCS subscriber found for link_id %p, conn_id %" PRIx32 "\n",
ue->link, ue->conn_id);
return NULL;
}
/* Receive MM/CC/... message from IuCS (SCCP user SAP).
* msg->dst must reference a struct ue_conn_ctx. link_id identifies the SCTP
* peer that sent the msg.
*
* For A-interface see libbsc/bsc_api.c gsm0408_rcvmsg(). */
int gsm0408_rcvmsg_iucs(struct gsm_network *network, struct msgb *msg)
{
int rc;
struct ue_conn_ctx *ue_ctx;
struct gsm_subscriber_connection *conn;
ue_ctx = (struct ue_conn_ctx*)msg->dst;
/* TODO: are there message types that could allow us to skip this
* search? */
conn = subscr_conn_lookup_iu(network, ue_ctx);
if (conn) {
/* if we already have a connection, handle DTAP.
gsm0408_dispatch() is aka msc_dtap() */
/* Make sure we don't receive RR over IuCS; otherwise all
* messages handled by gsm0408_dispatch() are of interest (CC,
* MM, SMS, NS_SS, maybe even MM_GPRS and SM_GPRS). */
struct gsm48_hdr *gh = msgb_l3(msg);
uint8_t pdisc = gh->proto_discr & 0x0f;
OSMO_ASSERT(pdisc != GSM48_PDISC_RR);
rc = gsm0408_dispatch(conn, msg);
} else {
/* allocate a new connection */
conn = subscr_conn_allocate_iu(network, ue_ctx);
if (!conn)
abort();
rc = msc_compl_l3(conn, msg, 0);
if (rc != BSC_API_CONN_POL_ACCEPT) {
subscr_con_free(conn);
rc = -1;
}
else
rc = 0;
}
return rc;
}
int iucs_submit_dtap(struct gsm_subscriber_connection *conn,
struct msgb *msg)
{
OSMO_ASSERT(conn->via_iface == IFACE_IU);
msg->dst = conn->iu.ue_ctx;
return iu_tx(msg, 0);
}
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