nat: And out the skip_indicator/transaction id from the gsm48 header

We need to and out the protocol discriminator as call control
might have use transactions. This has only failed for the USSD
filter so far as this must deal with transactions.

3 files changed, 17 insertions, 11 deletions

diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat.c b/openbsc/src/osmo-bsc_nat/bsc_nat.c
index 8c164a270..d38256587 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat.c
@@ -542,15 +542,16 @@ static void update_con_authorize(struct sccp_connections *con,
 	    parsed->gsm_type == BSS_MAP_MSG_CIPHER_MODE_CMD) {
 		con->authorized = 1;
 	} else if (parsed->bssap == BSSAP_MSG_DTAP) {
-		uint8_t msg_type;
+		uint8_t msg_type, proto;
 		uint32_t len;
 		struct gsm48_hdr *hdr48;
 		hdr48 = bsc_unpack_dtap(parsed, msg, &len);
 		if (!hdr48)
 			return;
 
+		proto = hdr48->proto_discr & 0x0f;
 		msg_type = hdr48->msg_type & 0xbf;
-		if (hdr48->proto_discr == GSM48_PDISC_MM &&
+		if (proto == GSM48_PDISC_MM &&
 		    msg_type == GSM48_MT_MM_CM_SERV_ACC)
 			con->authorized = 1;
 	}
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
index 4258364fe..4e7286e6f 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
@@ -500,7 +500,7 @@ int bsc_nat_filter_sccp_cr(struct bsc_connection *bsc, struct msgb *msg,
 	struct gsm48_hdr *hdr48;
 	int hdr48_len;
 	int len;
-	uint8_t msg_type;
+	uint8_t msg_type, proto;
 
 	*con_type = NAT_CON_TYPE_NONE;
 	*imsi = NULL;
@@ -538,18 +538,19 @@ int bsc_nat_filter_sccp_cr(struct bsc_connection *bsc, struct msgb *msg,
 
 	hdr48 = (struct gsm48_hdr *) TLVP_VAL(&tp, GSM0808_IE_LAYER_3_INFORMATION);
 
+	proto = hdr48->proto_discr & 0x0f;
 	msg_type = hdr48->msg_type & 0xbf;
-	if (hdr48->proto_discr == GSM48_PDISC_MM &&
+	if (proto == GSM48_PDISC_MM &&
 	    msg_type == GSM48_MT_MM_LOC_UPD_REQUEST) {
 		*con_type = NAT_CON_TYPE_LU;
 		return _cr_check_loc_upd(bsc, &hdr48->data[0], hdr48_len - sizeof(*hdr48), imsi);
-	} else if (hdr48->proto_discr == GSM48_PDISC_MM &&
+	} else if (proto == GSM48_PDISC_MM &&
 		  msg_type == GSM48_MT_MM_CM_SERV_REQ) {
 		*con_type = NAT_CON_TYPE_CM_SERV_REQ;
 		return _cr_check_cm_serv_req(bsc, &hdr48->data[0],
 					     hdr48_len - sizeof(*hdr48),
 					     con_type, imsi);
-	} else if (hdr48->proto_discr == GSM48_PDISC_RR &&
+	} else if (proto == GSM48_PDISC_RR &&
 		   msg_type == GSM48_MT_RR_PAG_RESP) {
 		*con_type = NAT_CON_TYPE_PAG_RESP;
 		return _cr_check_pag_resp(bsc, &hdr48->data[0], hdr48_len - sizeof(*hdr48), imsi);
@@ -583,7 +584,7 @@ int bsc_nat_filter_dt(struct bsc_connection *bsc, struct msgb *msg,
 		      struct sccp_connections *con, struct bsc_nat_parsed *parsed)
 {
 	uint32_t len;
-	uint8_t msg_type;
+	uint8_t msg_type, proto;
 	struct gsm48_hdr *hdr48;
 
 	if (con->imsi_checked)
@@ -597,8 +598,9 @@ int bsc_nat_filter_dt(struct bsc_connection *bsc, struct msgb *msg,
 	if (!hdr48)
 		return -1;
 
+	proto = hdr48->proto_discr & 0x0f;
 	msg_type = hdr48->msg_type & 0xbf;
-	if (hdr48->proto_discr == GSM48_PDISC_MM &&
+	if (proto == GSM48_PDISC_MM &&
 	    msg_type == GSM48_MT_MM_ID_RESP) {
 		return _dt_check_id_resp(bsc, &hdr48->data[0], len - sizeof(*hdr48), con);
 	} else {
@@ -745,7 +747,7 @@ struct msgb *bsc_nat_rewrite_setup(struct bsc_nat *nat, struct msgb *msg, struct
 	struct tlv_parsed tp;
 	struct gsm48_hdr *hdr48;
 	uint32_t len;
-	uint8_t msg_type;
+	uint8_t msg_type, proto;
 	unsigned int payload_len;
 	struct gsm_mncc_number called;
 	struct msg_entry *entry;
@@ -771,8 +773,9 @@ struct msgb *bsc_nat_rewrite_setup(struct bsc_nat *nat, struct msgb *msg, struct
 	if (!hdr48)
 		return msg;
 
+	proto = hdr48->proto_discr & 0x0f;
 	msg_type = hdr48->msg_type & 0xbf;
-	if (hdr48->proto_discr != GSM48_PDISC_CC ||
+	if (proto != GSM48_PDISC_CC ||
 	    msg_type != GSM48_MT_CC_SETUP)
 		return msg;
 
diff --git a/openbsc/src/osmo-bsc_nat/bsc_ussd.c b/openbsc/src/osmo-bsc_nat/bsc_ussd.c
index fd38f7800..48ecad57f 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_ussd.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_ussd.c
@@ -309,6 +309,7 @@ int bsc_check_ussd(struct sccp_connections *con, struct bsc_nat_parsed *parsed,
 {
 	uint32_t len;
 	uint8_t msg_type;
+	uint8_t proto;
 	struct gsm48_hdr *hdr48;
 	struct bsc_nat_acc_lst *lst;
 	struct ussd_request req;
@@ -343,8 +344,9 @@ int bsc_check_ussd(struct sccp_connections *con, struct bsc_nat_parsed *parsed,
 	if (!hdr48)
 		return 0;
 
+	proto = hdr48->proto_discr & 0x0f;
 	msg_type = hdr48->msg_type & 0xbf;
-	if (hdr48->proto_discr != GSM48_PDISC_NC_SS || msg_type != GSM0480_MTYPE_REGISTER)
+	if (proto != GSM48_PDISC_NC_SS || msg_type != GSM0480_MTYPE_REGISTER)
 		return 0;
 
 	/* now check if it is a IMSI we care about */