gbproxy: Pass TLLI as LSP towards NS to facilitate load sharing
Change-Id: I6aef26c126b330a393fc2be5f558b6d5f1d9f7f4
diff --git a/src/gbproxy/gb_proxy.c b/src/gbproxy/gb_proxy.c
index 39b9ffd..9009651 100644
--- a/src/gbproxy/gb_proxy.c
+++ b/src/gbproxy/gb_proxy.c
@@ -811,6 +811,7 @@
struct gprs_ns2_inst *nsi = peer->cfg->nsi;
struct osmo_gprs_ns2_prim nsp = {};
struct msgb *msg = bssgp_msgb_copy(old_msg, "msgb_relay2peer");
+ uint32_t tlli;
int rc;
DEBUGP(DGPRS, "NSEI=%u proxying SGSN->BSS (NS_BVCI=%u, NSEI=%u)\n",
@@ -822,6 +823,14 @@
/* Strip the old NS header, it will be replaced with a new one */
strip_ns_hdr(msg);
+ /* TS 48.018 Section 5.4.2: The link selector parameter is
+ * defined in 3GPP TS 48.016. At one side of the Gb interface,
+ * all BSSGP UNITDATA PDUs related to an MS shall be passed with
+ * the same LSP, e.g. the LSP contains the MS's TLLI, to the
+ * underlying network service. */
+ if (gprs_gb_parse_tlli(msgb_data(msg), msgb_length(msg), &tlli) == 1)
+ nsp.u.unitdata.link_selector = tlli;
+
osmo_prim_init(&nsp.oph, SAP_NS, PRIM_NS_UNIT_DATA,
PRIM_OP_REQUEST, msg);
rc = gprs_ns2_recv_prim(nsi, &nsp.oph);