04.08: apply new bitmask functions, fix bitmask use

Replace hardcoded protocol discriminator and message type bitmasks with
function calls recently introduced in libosmocore.

Note that the release 98 bitmasks slightly differ from the release 99 bitmasks.
This patch uses the "default" gsm48_hdr_msg_type invocation, thus it depends on
libosmocore whether 98 or 99 bitmasks are used.

In some places, use of the bitmask was erratic. Fix these implicitly by
employing the bitmask functions:

 * silent_call.c: silent_call_reroute(): add missing bitmask for MM.
 * bsc_msg_filter.c: bsc_msg_filter_initial(): RR vs. MM messages.
 * osmo_bsc_filter.c: bsc_find_msc() and bsc_scan_bts_msg(): RR vs. MM
   messages.
 * bsc_nat_rewrite.c: bsc_nat_rewrite_msg(): SMS vs. CC messages.
 * bsc_ussd.c: no bitmask is applicable for the message types used here.
 * gb_proxy.c: gbproxy_imsi_acquisition(): missing bit mask for pdisc.

In gprs_gb_parse.c: gprs_gb_parse_dtap(), add a log notice for unexpected
message types.

12 files changed, 45 insertions, 35 deletions

diff --git a/openbsc/src/gprs/gb_proxy.c b/openbsc/src/gprs/gb_proxy.c
index 955133562..6e6b03b86 100644
--- a/openbsc/src/gprs/gb_proxy.c
+++ b/openbsc/src/gprs/gb_proxy.c
@@ -462,8 +462,8 @@ static int gbproxy_imsi_acquisition(struct gbproxy_peer *peer,
 	if (link_info->imsi_acq_pending && link_info->imsi_len > 0) {
 		int is_ident_resp =
 			parse_ctx->g48_hdr &&
-			parse_ctx->g48_hdr->proto_discr == GSM48_PDISC_MM_GPRS &&
-			parse_ctx->g48_hdr->msg_type == GSM48_MT_GMM_ID_RESP;
+			gsm48_hdr_pdisc(parse_ctx->g48_hdr) == GSM48_PDISC_MM_GPRS &&
+			gsm48_hdr_msg_type(parse_ctx->g48_hdr) == GSM48_MT_GMM_ID_RESP;
 
 		/* The IMSI is now available */
 		gbproxy_flush_stored_messages(peer, msg, now, link_info,
diff --git a/openbsc/src/gprs/gprs_gb_parse.c b/openbsc/src/gprs/gprs_gb_parse.c
index 609685407..63ac9028d 100644
--- a/openbsc/src/gprs/gprs_gb_parse.c
+++ b/openbsc/src/gprs/gprs_gb_parse.c
@@ -329,17 +329,20 @@ int gprs_gb_parse_dtap(uint8_t *data, size_t data_len,
 		       struct gprs_gb_parse_context *parse_ctx)
 {
 	struct gsm48_hdr *g48h;
+	uint8_t pdisc;
+	uint8_t msg_type;
 
 	if (gprs_shift_v_fixed(&data, &data_len, sizeof(*g48h), (uint8_t **)&g48h) <= 0)
 		return 0;
 
 	parse_ctx->g48_hdr = g48h;
 
-	if ((g48h->proto_discr & 0x0f) != GSM48_PDISC_MM_GPRS &&
-	    (g48h->proto_discr & 0x0f) != GSM48_PDISC_SM_GPRS)
+	pdisc = gsm48_hdr_pdisc(g48h);
+	if (pdisc != GSM48_PDISC_MM_GPRS && pdisc != GSM48_PDISC_SM_GPRS)
 		return 1;
 
-	switch (g48h->msg_type) {
+	msg_type = gsm48_hdr_msg_type(g48h);
+	switch (msg_type) {
 	case GSM48_MT_GMM_ATTACH_REQ:
 		return gprs_gb_parse_gmm_attach_req(data, data_len, parse_ctx);
 
@@ -376,6 +379,10 @@ int gprs_gb_parse_dtap(uint8_t *data, size_t data_len,
 		break;
 
 	default:
+		LOGP(DLLC, LOGL_NOTICE,
+		     "Unknown GSM 04.08 message type 0x%02hhx for protocol"
+		     " discriminator 0x%02hhx.\n",
+		     msg_type, pdisc);
 		break;
 	};
 
diff --git a/openbsc/src/gprs/gprs_gmm.c b/openbsc/src/gprs/gprs_gmm.c
index 47302a359..9275e05a5 100644
--- a/openbsc/src/gprs/gprs_gmm.c
+++ b/openbsc/src/gprs/gprs_gmm.c
@@ -2393,7 +2393,7 @@ int gsm0408_gprs_rcvmsg_iu(struct msgb *msg, struct gprs_ra_id *ra_id,
 int gsm0408_gprs_rcvmsg_gb(struct msgb *msg, struct gprs_llc_llme *llme)
 {
 	struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_gmmh(msg);
-	uint8_t pdisc = gh->proto_discr & 0x0f;
+	uint8_t pdisc = gsm48_hdr_pdisc(gh);
 	struct sgsn_mm_ctx *mmctx;
 	struct gprs_ra_id ra_id;
 	int rc = -EINVAL;
diff --git a/openbsc/src/libbsc/bsc_api.c b/openbsc/src/libbsc/bsc_api.c
index ec3d92677..d9c34d035 100644
--- a/openbsc/src/libbsc/bsc_api.c
+++ b/openbsc/src/libbsc/bsc_api.c
@@ -570,6 +570,7 @@ static void dispatch_dtap(struct gsm_subscriber_connection *conn,
 	struct bsc_api *api = msg->lchan->ts->trx->bts->network->bsc_api;
 	struct gsm48_hdr *gh;
 	uint8_t pdisc;
+	uint8_t msg_type;
 	int rc;
 
 	if (msgb_l3len(msg) < sizeof(*gh)) {
@@ -578,7 +579,8 @@ static void dispatch_dtap(struct gsm_subscriber_connection *conn,
 	}
 
 	gh = msgb_l3(msg);
-	pdisc = gh->proto_discr & 0x0f;
+	pdisc = gsm48_hdr_pdisc(gh);
+	msg_type = gsm48_hdr_msg_type(gh);
 
 	/* the idea is to handle all RR messages here, and only hand
 	 * MM/CC/SMS-CP/LCS up to the MSC.  Some messages like PAGING
@@ -588,7 +590,7 @@ static void dispatch_dtap(struct gsm_subscriber_connection *conn,
 	 * will call api->compl_l3() for it */
 	switch (pdisc) {
 	case GSM48_PDISC_RR:
-		switch (gh->msg_type) {
+		switch (msg_type) {
 		case GSM48_MT_RR_GPRS_SUSP_REQ:
 			DEBUGP(DRR, "GRPS SUSPEND REQUEST\n");
 			break;
@@ -647,7 +649,7 @@ static void dispatch_dtap(struct gsm_subscriber_connection *conn,
 			 * messages, but we'd rather forward what we
 			 * don't know than drop it... */
 			LOGP(DRR, LOGL_NOTICE, "BSC: Passing unknown 04.08 "
-			     "RR message type 0x%02x to MSC\n", gh->msg_type);
+			     "RR message type 0x%02x to MSC\n", msg_type);
 			if (api->dtap)
 				api->dtap(conn, link_id, msg);
 		}
diff --git a/openbsc/src/libfilter/bsc_msg_filter.c b/openbsc/src/libfilter/bsc_msg_filter.c
index eafeff4db..115d376cb 100644
--- a/openbsc/src/libfilter/bsc_msg_filter.c
+++ b/openbsc/src/libfilter/bsc_msg_filter.c
@@ -339,15 +339,15 @@ int bsc_msg_filter_initial(struct gsm48_hdr *hdr48, size_t hdr48_len,
 	cause->lu_reject_cause = GSM48_REJECT_PLMN_NOT_ALLOWED;
 	*imsi = NULL;
 
-	proto = hdr48->proto_discr & 0x0f;
-	msg_type = hdr48->msg_type & 0xbf;
+	proto = gsm48_hdr_pdisc(hdr48);
+	msg_type = gsm48_hdr_msg_type(hdr48);
 	if (proto == GSM48_PDISC_MM &&
 	    msg_type == GSM48_MT_MM_LOC_UPD_REQUEST) {
 		*con_type = FLT_CON_TYPE_LU;
 		ret = _cr_check_loc_upd(req->ctx, &hdr48->data[0],
 					hdr48_len - sizeof(*hdr48), imsi);
 	} else if (proto == GSM48_PDISC_MM &&
-		  msg_type == GSM48_MT_MM_CM_SERV_REQ) {
+		   msg_type == GSM48_MT_MM_CM_SERV_REQ) {
 		*con_type = FLT_CON_TYPE_CM_SERV_REQ;
 		ret = _cr_check_cm_serv_req(req->ctx, &hdr48->data[0],
 					     hdr48_len - sizeof(*hdr48),
@@ -388,8 +388,8 @@ int bsc_msg_filter_data(struct gsm48_hdr *hdr48, size_t len,
 	if (state->imsi_checked)
 		return 0;
 
-	proto = hdr48->proto_discr & 0x0f;
-	msg_type = hdr48->msg_type & 0xbf;
+	proto = gsm48_hdr_pdisc(hdr48);
+	msg_type = gsm48_hdr_msg_type(hdr48);
 	if (proto != GSM48_PDISC_MM || msg_type != GSM48_MT_MM_ID_RESP)
 		return 0;
 
diff --git a/openbsc/src/libmsc/gsm_04_08.c b/openbsc/src/libmsc/gsm_04_08.c
index 0129563aa..f7ecae4a7 100644
--- a/openbsc/src/libmsc/gsm_04_08.c
+++ b/openbsc/src/libmsc/gsm_04_08.c
@@ -1171,7 +1171,7 @@ static int gsm0408_rcv_mm(struct gsm_subscriber_connection *conn, struct msgb *m
 	struct gsm48_hdr *gh = msgb_l3(msg);
 	int rc = 0;
 
-	switch (gh->msg_type & 0xbf) {
+	switch (gsm48_hdr_msg_type(gh)) {
 	case GSM48_MT_MM_LOC_UPD_REQUEST:
 		DEBUGP(DMM, "LOCATION UPDATING REQUEST: ");
 		rc = mm_rx_loc_upd_req(conn, msg);
@@ -1842,7 +1842,7 @@ static void gsm48_start_cc_timer(struct gsm_trans *trans, int current,
 static int gsm48_cc_rx_setup(struct gsm_trans *trans, struct msgb *msg)
 {
 	struct gsm48_hdr *gh = msgb_l3(msg);
-	uint8_t msg_type = gh->msg_type & 0xbf;
+	uint8_t msg_type = gsm48_hdr_msg_type(gh);
 	unsigned int payload_len = msgb_l3len(msg) - sizeof(*gh);
 	struct tlv_parsed tp;
 	struct gsm_mncc setup;
@@ -3498,7 +3498,7 @@ static struct datastate {
 static int gsm0408_rcv_cc(struct gsm_subscriber_connection *conn, struct msgb *msg)
 {
 	struct gsm48_hdr *gh = msgb_l3(msg);
-	uint8_t msg_type = gh->msg_type & 0xbf;
+	uint8_t msg_type = gsm48_hdr_msg_type(gh);
 	uint8_t transaction_id = ((gh->proto_discr & 0xf0) ^ 0x80) >> 4; /* flip */
 	struct gsm_trans *trans = NULL;
 	int i, rc = 0;
@@ -3591,7 +3591,7 @@ int gsm0408_new_conn(struct gsm_subscriber_connection *conn)
 int gsm0408_dispatch(struct gsm_subscriber_connection *conn, struct msgb *msg)
 {
 	struct gsm48_hdr *gh = msgb_l3(msg);
-	uint8_t pdisc = gh->proto_discr & 0x0f;
+	uint8_t pdisc = gsm48_hdr_pdisc(gh);
 	int rc = 0;
 
 	LOGP(DRLL, LOGL_DEBUG, "Dispatching 04.08 message, pdisc=%d\n", pdisc);
diff --git a/openbsc/src/libmsc/silent_call.c b/openbsc/src/libmsc/silent_call.c
index 26be5a7e2..5d0b6ef19 100644
--- a/openbsc/src/libmsc/silent_call.c
+++ b/openbsc/src/libmsc/silent_call.c
@@ -97,7 +97,8 @@ static const struct msg_match silent_call_accept[] = {
 int silent_call_reroute(struct gsm_subscriber_connection *conn, struct msgb *msg)
 {
 	struct gsm48_hdr *gh = msgb_l3(msg);
-	uint8_t pdisc = gh->proto_discr & 0x0f;
+	uint8_t pdisc = gsm48_hdr_pdisc(gh);
+	uint8_t msg_type = gsm48_hdr_msg_type(gh);
 	int i;
 
 	/* if we're not part of a silent call, never reroute */
@@ -107,7 +108,7 @@ int silent_call_reroute(struct gsm_subscriber_connection *conn, struct msgb *msg
 	/* check if we are a special message that is handled in openbsc */
 	for (i = 0; i < ARRAY_SIZE(silent_call_accept); i++) {
 		if (silent_call_accept[i].pdisc == pdisc &&
-		    silent_call_accept[i].msg_type == gh->msg_type)
+		    silent_call_accept[i].msg_type == msg_type)
 			return 0;
 	}
 
diff --git a/openbsc/src/osmo-bsc/osmo_bsc_api.c b/openbsc/src/osmo-bsc/osmo_bsc_api.c
index 7e9894cdb..bf5db5a76 100644
--- a/openbsc/src/osmo-bsc/osmo_bsc_api.c
+++ b/openbsc/src/osmo-bsc/osmo_bsc_api.c
@@ -180,8 +180,8 @@ static void bsc_send_ussd_no_srv(struct gsm_subscriber_connection *conn,
 		return;
 
 	gh = msgb_l3(msg);
-	pdisc = gh->proto_discr & 0x0f;
-	mtype = gh->msg_type & 0xbf;
+	pdisc = gsm48_hdr_pdisc(gh);
+	mtype = gsm48_hdr_msg_type(gh);
 
 	/* Is CM service request? */
 	if (pdisc == GSM48_PDISC_MM && mtype == GSM48_MT_MM_CM_SERV_REQ) {
@@ -341,8 +341,8 @@ static int handle_cc_setup(struct gsm_subscriber_connection *conn,
 			   struct msgb *msg)
 {
 	struct gsm48_hdr *gh = msgb_l3(msg);
-	uint8_t pdisc = gh->proto_discr & 0x0f;
-	uint8_t mtype = gh->msg_type & 0xbf;
+	uint8_t pdisc = gsm48_hdr_pdisc(gh);
+	uint8_t mtype = gsm48_hdr_msg_type(gh);
 
 	struct osmo_msc_data *msc;
 	struct gsm_mncc_number called;
diff --git a/openbsc/src/osmo-bsc/osmo_bsc_filter.c b/openbsc/src/osmo-bsc/osmo_bsc_filter.c
index b68fccd18..2e2db8875 100644
--- a/openbsc/src/osmo-bsc/osmo_bsc_filter.c
+++ b/openbsc/src/osmo-bsc/osmo_bsc_filter.c
@@ -141,8 +141,8 @@ struct osmo_msc_data *bsc_find_msc(struct gsm_subscriber_connection *conn,
 	}
 
 	gh = msgb_l3(msg);
-	pdisc = gh->proto_discr & 0x0f;
-	mtype = gh->msg_type & 0xbf;
+	pdisc = gsm48_hdr_pdisc(gh);
+	mtype = gsm48_hdr_msg_type(gh);
 
 	/*
 	 * We are asked to select a MSC here but they are not equal. We
@@ -212,8 +212,8 @@ paging:
 int bsc_scan_bts_msg(struct gsm_subscriber_connection *conn, struct msgb *msg)
 {
 	struct gsm48_hdr *gh = msgb_l3(msg);
-	uint8_t pdisc = gh->proto_discr & 0x0f;
-	uint8_t mtype = gh->msg_type & 0xbf;
+	uint8_t pdisc = gsm48_hdr_pdisc(gh);
+	uint8_t mtype = gsm48_hdr_msg_type(gh);
 
 	if (pdisc == GSM48_PDISC_MM) {
 		if (mtype == GSM48_MT_MM_LOC_UPD_REQUEST)
@@ -348,7 +348,7 @@ int bsc_scan_msc_msg(struct gsm_subscriber_connection *conn, struct msgb *msg)
 	gh = (struct gsm48_hdr *) msgb_l3(msg);
 	length -= (const char *)&gh->data[0] - (const char *)gh;
 
-	mtype = gh->msg_type & 0xbf;
+	mtype = gsm48_hdr_msg_type(gh);
 	net = conn->bts->network;
 	msc = conn->sccp_con->msc;
 
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat.c b/openbsc/src/osmo-bsc_nat/bsc_nat.c
index cdab4064d..cacb9199d 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat.c
@@ -670,8 +670,8 @@ static void update_con_authorize(struct nat_sccp_connection *con,
 		if (!hdr48)
 			return;
 
-		proto = hdr48->proto_discr & 0x0f;
-		msg_type = hdr48->msg_type & 0xbf;
+		proto = gsm48_hdr_pdisc(hdr48);
+		msg_type = gsm48_hdr_msg_type(hdr48);
 		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_rewrite.c b/openbsc/src/osmo-bsc_nat/bsc_nat_rewrite.c
index ca5670ca4..58667fe8c 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_rewrite.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_rewrite.c
@@ -594,8 +594,8 @@ struct msgb *bsc_nat_rewrite_msg(struct bsc_nat *nat, struct msgb *msg, struct b
 		return msg;
 
 	link_id = msg->l3h[1];
-	proto = hdr48->proto_discr & 0x0f;
-	msg_type = hdr48->msg_type & 0xbf;
+	proto = gsm48_hdr_pdisc(hdr48);
+	msg_type = gsm48_hdr_msg_type(hdr48);
 
 	if (proto == GSM48_PDISC_CC && msg_type == GSM48_MT_CC_SETUP)
 		new_msg = rewrite_setup(nat, msg, parsed, imsi, hdr48, len);
diff --git a/openbsc/src/osmo-bsc_nat/bsc_ussd.c b/openbsc/src/osmo-bsc_nat/bsc_ussd.c
index 108241421..2905c85b0 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_ussd.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_ussd.c
@@ -407,8 +407,8 @@ int bsc_ussd_check(struct nat_sccp_connection *con, struct bsc_nat_parsed *parse
 	if (!hdr48)
 		return 0;
 
-	proto = hdr48->proto_discr & 0x0f;
-	msg_type = hdr48->msg_type & 0xbf;
+	proto = gsm48_hdr_pdisc(hdr48);
+	msg_type = gsm48_hdr_msg_type(hdr48);
 	ti = (hdr48->proto_discr & 0x70) >> 4;
 	if (proto != GSM48_PDISC_NC_SS)
 		return 0;