smpp: Move the coding/mode detection into a utils file

Make sure to not ever have issues with this code again, move the
utility code to a new file and create a basic testcase. The method
currently has 100% line and branch coverage. My initial patched
missed the smpp_utils.c file and I re-did the copying (and verifying
the branch coverage)

4 files changed, 69 insertions, 36 deletions

diff --git a/openbsc/src/libmsc/Makefile.am b/openbsc/src/libmsc/Makefile.am
index 7faee430a..c36ba926b 100644
--- a/openbsc/src/libmsc/Makefile.am
+++ b/openbsc/src/libmsc/Makefile.am
@@ -19,5 +19,5 @@ libmsc_a_SOURCES =	auth.c \
 			osmo_msc.c
 
 if BUILD_SMPP
-libmsc_a_SOURCES += smpp_smsc.c smpp_openbsc.c smpp_vty.c
+libmsc_a_SOURCES += smpp_smsc.c smpp_openbsc.c smpp_vty.c smpp_utils.c
 endif
diff --git a/openbsc/src/libmsc/smpp_openbsc.c b/openbsc/src/libmsc/smpp_openbsc.c
index f898cae6f..8e0085d0c 100644
--- a/openbsc/src/libmsc/smpp_openbsc.c
+++ b/openbsc/src/libmsc/smpp_openbsc.c
@@ -79,9 +79,6 @@ static struct tlv_t *find_tlv(struct tlv_t *head, uint16_t tag)
 	return NULL;
 }
 
-#define MODE_7BIT	7
-#define MODE_8BIT	8
-
 /*! \brief convert from submit_sm_t to gsm_sms */
 static int submit_to_sms(struct gsm_sms **psms, struct gsm_network *net,
 			 const struct submit_sm_t *submit)
@@ -469,39 +466,8 @@ static int deliver_to_esme(struct osmo_esme *esme, struct gsm_sms *sms,
 
 	/* Figure out SMPP DCS from TP-DCS */
 	dcs = sms->data_coding_scheme;
-	if ((dcs & 0xF0) == 0xF0) {
-		if (dcs & 0x04) {
-			/* bit 2 == 1: 8bit data */
-			deliver.data_coding = 0x02;
-			mode = MODE_8BIT;
-		} else {
-			/* bit 2 == 0: default alphabet */
-			deliver.data_coding = 0x01;
-			mode = MODE_7BIT;
-		}
-	} else if ((dcs & 0xE0) == 0) {
-		switch (dcs & 0xC) {
-		case 0:
-			deliver.data_coding = 0x01;
-			mode = MODE_7BIT;
-			break;
-		case 4:
-			deliver.data_coding = 0x02;
-			mode = MODE_8BIT;
-			break;
-		case 8:
-			deliver.data_coding = 0x08;	/* UCS-2 */
-			mode = MODE_8BIT;
-			break;
-		default:
-			goto unknown_mo;
-		}
-	} else {
-unknown_mo:
-		LOGP(DLSMS, LOGL_ERROR, "SMPP MO Unknown Data Coding 0x%02x\n",
-			dcs);
+	if (smpp_determine_scheme(dcs, &deliver.data_coding, &mode) == -1)
 		return -1;
-	}
 
 	/* Transparently pass on DCS via SMPP if requested */
 	if (esme->acl && esme->acl->dcs_transparent)
diff --git a/openbsc/src/libmsc/smpp_smsc.h b/openbsc/src/libmsc/smpp_smsc.h
index 747dc3a2c..21d28dda6 100644
--- a/openbsc/src/libmsc/smpp_smsc.h
+++ b/openbsc/src/libmsc/smpp_smsc.h
@@ -15,6 +15,9 @@
 #define SMPP_SYS_ID_LEN	16
 #define SMPP_PASSWD_LEN	16
 
+#define MODE_7BIT	7
+#define MODE_8BIT	8
+
 enum esme_read_state {
 	READ_ST_IN_LEN = 0,
 	READ_ST_IN_MSG = 1,
@@ -126,4 +129,6 @@ int smpp_route_pfx_del(struct osmo_smpp_acl *acl,
 		       const struct osmo_smpp_addr *pfx);
 
 int smpp_vty_init(void);
+
+int smpp_determine_scheme(uint8_t dcs, uint8_t *data_coding, int *mode);
 #endif
diff --git a/openbsc/src/libmsc/smpp_utils.c b/openbsc/src/libmsc/smpp_utils.c
new file mode 100644
index 000000000..d0850d8c1
--- /dev/null
+++ b/openbsc/src/libmsc/smpp_utils.c
@@ -0,0 +1,62 @@
+
+/* (C) 2012-2013 by Harald Welte <laforge@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+#include "smpp_smsc.h"
+#include <openbsc/debug.h>
+
+
+int smpp_determine_scheme(uint8_t dcs, uint8_t *data_coding, int *mode)
+{
+	if ((dcs & 0xF0) == 0xF0) {
+		if (dcs & 0x04) {
+			/* bit 2 == 1: 8bit data */
+			*data_coding = 0x02;
+			*mode = MODE_8BIT;
+		} else {
+			/* bit 2 == 0: default alphabet */
+			*data_coding = 0x01;
+			*mode = MODE_7BIT;
+		}
+	} else if ((dcs & 0xE0) == 0) {
+		switch (dcs & 0xC) {
+		case 0:
+			*data_coding = 0x01;
+			*mode = MODE_7BIT;
+			break;
+		case 4:
+			*data_coding = 0x02;
+			*mode = MODE_8BIT;
+			break;
+		case 8:
+			*data_coding = 0x08;     /* UCS-2 */
+			*mode = MODE_8BIT;
+			break;
+		default:
+			goto unknown_mo;
+		}
+	} else {
+unknown_mo:
+		LOGP(DLSMS, LOGL_ERROR, "SMPP MO Unknown Data Coding 0x%02x\n", dcs);
+		return -1;
+	}
+
+	return 0;
+
+}