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-rw-r--r--src/sgsn/sgsn_rim.c67
1 files changed, 67 insertions, 0 deletions
diff --git a/src/sgsn/sgsn_rim.c b/src/sgsn/sgsn_rim.c
new file mode 100644
index 00000000..71e6d988
--- /dev/null
+++ b/src/sgsn/sgsn_rim.c
@@ -0,0 +1,67 @@
+
+#include <stdio.h>
+
+#include <errno.h>
+#include <stdint.h>
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/gsm/tlv.h>
+#include <osmocom/vty/logging.h>
+#include <osmocom/gprs/gprs_ns.h>
+#include <osmocom/gprs/gprs_bssgp.h>
+#include <osmocom/gprs/gprs_bssgp_rim.h>
+#include <osmocom/sgsn/sgsn_rim.h>
+#include <osmocom/sgsn/debug.h>
+
+/* Find an NSEI for the destination cell, this function works only for GERAN! */
+static int find_dest_nsei_geran(struct bssgp_rim_routing_info *dest_rim_ri, uint16_t nsei)
+{
+ struct bssgp_bvc_ctx *bvc_ctx;
+
+ OSMO_ASSERT(dest_rim_ri->discr == BSSGP_RIM_ROUTING_INFO_GERAN);
+
+ bvc_ctx = btsctx_by_raid_cid(&dest_rim_ri->geran.raid, dest_rim_ri->geran.cid);
+ if (!bvc_ctx) {
+ LOGP(DRIM, LOGL_ERROR, "BSSGP RIM (NSEI=%u) cannot find NSEI for destination cell\n", nsei);
+ return -EINVAL;
+ }
+
+ return bvc_ctx->nsei;
+}
+
+int sgsn_rim_rx(struct osmo_bssgp_prim *bp, struct msgb *msg)
+{
+ struct bssgp_ran_information_pdu *pdu = &bp->u.rim_pdu;
+ int d_nsei;
+ uint16_t nsei = msgb_nsei(msg);
+
+ /* At the moment we only support GERAN, so we block all other network
+ * types here. */
+ if (pdu->routing_info_dest.discr != BSSGP_RIM_ROUTING_INFO_GERAN) {
+ LOGP(DRIM, LOGL_ERROR,
+ "BSSGP RIM (NSEI=%u) only GERAN supported, destination cell is not a GERAN cell -- rejected.\n",
+ nsei);
+ /* At the moment we can only handle GERAN addresses, any other
+ * type of address will be consideres as an invalid address.
+ * see also: 3GPP TS 48.018, section 8c.3.1.3 */
+ return bssgp_tx_status(BSSGP_CAUSE_UNKN_RIM_AI, NULL, msg);
+ }
+ if (pdu->routing_info_src.discr != BSSGP_RIM_ROUTING_INFO_GERAN) {
+ LOGP(DRIM, LOGL_ERROR,
+ "BSSGP RIM (NSEI=%u) only GERAN supported, source cell is not a GERAN cell -- rejected.\n", nsei);
+ /* See comment above */
+ return bssgp_tx_status(BSSGP_CAUSE_UNKN_RIM_AI, NULL, msg);
+ }
+
+ d_nsei = find_dest_nsei_geran(&pdu->routing_info_dest, nsei);
+ if (d_nsei < 0) {
+ LOGP(DRIM, LOGL_NOTICE, "BSSGP RIM (NSEI=%u) Cell %s unknown to this sgsn\n",
+ nsei, bssgp_rim_ri_name(&pdu->routing_info_dest));
+ /* In case of an invalid destination address we respond with
+ * a BSSGP STATUS PDU, see also: 3GPP TS 48.018, section 8c.3.1.3 */
+ return bssgp_tx_status(BSSGP_CAUSE_UNKN_RIM_AI, NULL, msg);
+ }
+
+ /* Forward PDU as it is to the correct interface */
+ return bssgp_tx_rim(pdu, (uint16_t) d_nsei);
+}