3 files changed, 47 insertions, 4 deletions

diff --git a/openbsc/src/gprs/gb_proxy_patch.c b/openbsc/src/gprs/gb_proxy_patch.c
index b14809495..c1d2497db 100644
--- a/openbsc/src/gprs/gb_proxy_patch.c
+++ b/openbsc/src/gprs/gb_proxy_patch.c
@@ -327,6 +327,19 @@ void gbproxy_patch_bssgp(struct msgb *msg, uint8_t *bssgp, size_t bssgp_len,
 		}
 	}
 
+	if (parse_ctx->bssgp_ptmsi_enc && peer->cfg->patch_ptmsi) {
+		uint32_t ptmsi;
+		if (parse_ctx->to_bss)
+			ptmsi = link_info->tlli.ptmsi;
+		else
+			ptmsi = link_info->sgsn_tlli.ptmsi;
+
+		if (ptmsi != GSM_RESERVED_TMSI)
+			gbproxy_patch_ptmsi(
+				parse_ctx->bssgp_ptmsi_enc, peer,
+				ptmsi, parse_ctx->to_bss, "BSSGP P-TMSI");
+	}
+
 	if (parse_ctx->llc) {
 		uint8_t *llc = parse_ctx->llc;
 		size_t llc_len = parse_ctx->llc_len;
diff --git a/openbsc/src/gprs/gb_proxy_tlli.c b/openbsc/src/gprs/gb_proxy_tlli.c
index 467006e87..54e41e9e0 100644
--- a/openbsc/src/gprs/gb_proxy_tlli.c
+++ b/openbsc/src/gprs/gb_proxy_tlli.c
@@ -542,6 +542,30 @@ struct gbproxy_link_info *gbproxy_update_link_state_ul(
 	return link_info;
 }
 
+static struct gbproxy_link_info *gbproxy_get_link_info_dl(
+	struct gbproxy_peer *peer,
+	struct gprs_gb_parse_context *parse_ctx)
+{
+	struct gbproxy_link_info *link_info = NULL;
+
+	/* Which key to use depends on its availability only, if that fails, do
+	 * not retry it with another key (e.g. IMSI). */
+	if (parse_ctx->tlli_enc)
+		link_info = gbproxy_link_info_by_sgsn_tlli(peer, parse_ctx->tlli,
+							   parse_ctx->peer_nsei);
+
+	/* TODO: Get link_info by (SGSN) P-TMSI if that is available (see
+	 * GSM 08.18, 7.2) instead of using the IMSI as key. */
+	else if (parse_ctx->imsi)
+		link_info = gbproxy_link_info_by_imsi(
+			peer, parse_ctx->imsi, parse_ctx->imsi_len);
+
+	if (link_info)
+		link_info->is_deregistered = 0;
+
+	return link_info;
+}
+
 struct gbproxy_link_info *gbproxy_update_link_state_dl(
 	struct gbproxy_peer *peer,
 	time_t now,
@@ -549,9 +573,7 @@ struct gbproxy_link_info *gbproxy_update_link_state_dl(
 {
 	struct gbproxy_link_info *link_info = NULL;
 
-	if (parse_ctx->tlli_enc)
-		link_info = gbproxy_link_info_by_sgsn_tlli(
-			peer, parse_ctx->tlli, parse_ctx->peer_nsei);
+	link_info = gbproxy_get_link_info_dl(peer, parse_ctx);
 
 	if (parse_ctx->tlli_enc && parse_ctx->new_ptmsi_enc && link_info) {
 		/* A new P-TMSI has been signalled in the message,
diff --git a/openbsc/src/gprs/gprs_gb_parse.c b/openbsc/src/gprs/gprs_gb_parse.c
index 8e72cc819..6c6371ca0 100644
--- a/openbsc/src/gprs/gprs_gb_parse.c
+++ b/openbsc/src/gprs/gprs_gb_parse.c
@@ -596,7 +596,7 @@ int gprs_gb_parse_bssgp(uint8_t *bssgp, size_t bssgp_len,
 	}
 
 	if (TLVP_PRESENT(tp, BSSGP_IE_TMSI) && pdu_type == BSSGP_PDUT_PAGING_PS)
-		parse_ctx->ptmsi_enc = (uint8_t *)TLVP_VAL(tp, BSSGP_IE_TMSI);
+		parse_ctx->bssgp_ptmsi_enc = (uint8_t *)TLVP_VAL(tp, BSSGP_IE_TMSI);
 
 	if (TLVP_PRESENT(tp, BSSGP_IE_LLC_PDU)) {
 		uint8_t *llc = (uint8_t *)TLVP_VAL(tp, BSSGP_IE_LLC_PDU);
@@ -633,6 +633,7 @@ void gprs_gb_log_parse_context(int log_level,
 	if (!parse_ctx->tlli_enc &&
 	    !parse_ctx->ptmsi_enc &&
 	    !parse_ctx->new_ptmsi_enc &&
+	    !parse_ctx->bssgp_ptmsi_enc &&
 	    !parse_ctx->imsi)
 		return;
 
@@ -681,6 +682,13 @@ void gprs_gb_log_parse_context(int log_level,
 		sep = ",";
 	}
 
+	if (parse_ctx->bssgp_ptmsi_enc) {
+		uint32_t ptmsi = GSM_RESERVED_TMSI;
+		gprs_parse_tmsi(parse_ctx->bssgp_ptmsi_enc, &ptmsi);
+		LOGPC(DGPRS, log_level, "%s BSSGP PTMSI %08x", sep, ptmsi);
+		sep = ",";
+	}
+
 	if (parse_ctx->ptmsi_enc) {
 		uint32_t ptmsi = GSM_RESERVED_TMSI;
 		gprs_parse_tmsi(parse_ctx->ptmsi_enc, &ptmsi);