add MobileIdentity as separate class, add test

Use fixed applet-project.mk to put Mobile Identity implementations in a
separate class MobileIdentity.java.

That allows trivially testing the MobileIdentity implementation outside of an
actual SIM card environment: add a 'test' target to the Makefile and a
Test.java class that runs some tests.

4 files changed, 216 insertions, 140 deletions

diff --git a/sim-applet/Makefile b/sim-applet/Makefile
index 0300b4e..740ffd8 100644
--- a/sim-applet/Makefile
+++ b/sim-applet/Makefile
@@ -6,7 +6,8 @@ PACKAGE_AID     = 0xd0:0x70:0x02:0xCA:0x44:0x90:0x01
 PACKAGE_NAME    = org.osmocom.IMSIPseudo
 PACKAGE_VERSION = 1.0
 
-SOURCES = src/org/osmocom/IMSIPseudo/IMSIPseudo.java
+SOURCES = src/org/osmocom/IMSIPseudo/MobileIdentity.java src/org/osmocom/IMSIPseudo/IMSIPseudo.java
+
 CAP_FILE = build/javacard/org/osmocom/IMSIPseudo/javacard/IMSIPseudo.cap
 
 include ./applet-project.mk
@@ -37,3 +38,10 @@ remove:
 		--kid "$$KID1"
 
 delete: remove
+
+.PHONY: test
+test:
+	mkdir -p ./test/classes
+	javac -target 1.1 -source 1.3 -classpath test/classes -g -d ./test/classes src/org/osmocom/IMSIPseudo/MobileIdentity.java
+	javac -target 1.1 -source 1.3 -classpath test/classes -g -d ./test/classes src/org/osmocom/IMSIPseudo/Test.java
+	java -classpath test/classes org.osmocom.IMSIPseudo.Test
diff --git a/sim-applet/src/org/osmocom/IMSIPseudo/IMSIPseudo.java b/sim-applet/src/org/osmocom/IMSIPseudo/IMSIPseudo.java
index 00b6720..fdaca60 100755
--- a/sim-applet/src/org/osmocom/IMSIPseudo/IMSIPseudo.java
+++ b/sim-applet/src/org/osmocom/IMSIPseudo/IMSIPseudo.java
@@ -1,6 +1,7 @@
 /* Copyright 2020 sysmocom s.f.m.c. GmbH
  * SPDX-License-Identifier: Apache-2.0 */
 package org.osmocom.IMSIPseudo;
+import org.osmocom.IMSIPseudo.MobileIdentity;
 
 import sim.access.*;
 import sim.toolkit.*;
@@ -30,8 +31,6 @@ public class IMSIPseudo extends Applet implements ToolkitInterface, ToolkitConst
 						  'd', 'i', 'g', 'i', 't'};
 	private final Object[] itemListChangeIMSI = {changeIMSI, enterIMSI, setDigit1, setDigit2};
 
-	private static final byte MI_IMSI = 1;
-
 	private IMSIPseudo() {
 		gsmFile = SIMSystem.getTheSIMView();
 
@@ -130,140 +129,6 @@ public class IMSIPseudo extends Applet implements ToolkitInterface, ToolkitConst
 		showMsg(msg);
 	}
 
-	/* Convert BCD-encoded digit into printable character
-	 *  \param[in] bcd A single BCD-encoded digit
-	 *  \returns single printable character
-	 */
-	private byte bcd2char(byte bcd)
-	{
-		if (bcd < 0xa)
-			return (byte)('0' + bcd);
-		else
-			return (byte)('A' + (bcd - 0xa));
-	}
-
-	private byte char2bcd(byte c)
-	{
-		if (c >= '0' && c <= '9')
-			return (byte)(c - '0');
-		else if (c >= 'A' && c <= 'F')
-			return (byte)(0xa + (c - 'A'));
-		else if (c >= 'a' && c <= 'f')
-			return (byte)(0xa + (c - 'a'));
-		else
-			return 0;
-	}
-
-	/* Convert BCD to string.
-	 * The given nibble offsets are interpreted in BCD order, i.e. nibble 0 is bcd[0] & 0xf, nibble 1 is bcd[0] >> 4, nibble
-	 * 3 is bcd[1] & 0xf, etc..
-	 *  \param[out] dst  Output byte array.
-	 *  \param[in] dst_ofs  Where to start writing in dst.
-	 *  \param[in] dst_len  How many bytes are available at dst_ofs.
-	 *  \param[in] bcd  Binary coded data buffer.
-	 *  \param[in] start_nibble  Offset to start from, in nibbles.
-	 *  \param[in] end_nibble  Offset to stop before, in nibbles.
-	 *  \param[in] allow_hex  If false, return false if there are digits other than 0-9.
-	 *  \returns true on success, false otherwise
-	 */
-	private boolean bcd2str(byte dst[], byte dst_ofs, byte dst_len,
-				byte bcd[], byte start_nibble, byte end_nibble, boolean allow_hex)
-	{
-		byte nibble_i;
-		byte dst_i = dst_ofs;
-		byte dst_end = (byte)(dst_ofs + dst_len);
-		boolean rc = true;
-
-		for (nibble_i = start_nibble; nibble_i < end_nibble && dst_i < dst_end; nibble_i++, dst_i++) {
-			byte nibble = bcd[(byte)nibble_i >> 1];
-			if ((nibble_i & 1) != 0)
-				nibble >>= 4;
-			nibble &= 0xf;
-
-			if (!allow_hex && nibble > 9)
-				rc = false;
-
-			dst[dst_i] = bcd2char(nibble);
-		}
-
-		return rc;
-	}
-
-	private byte mi2str(byte dst[], byte dst_ofs, byte dst_len,
-			    byte mi[], boolean allow_hex)
-	{
-		/* The IMSI byte array by example:
-		 * 08 99 10 07 00 00 10 74 90
-		 *
-		 * This is encoded according to 3GPP TS 24.008 10.5.1.4 Mobile
-		 * Identity, short the Mobile Identity IEI:
-		 *
-		 * 08 length for the following MI, in bytes.
-		 *  9 = 0b1001
-		 *	1 = odd nr of digits
-		 *	 001 = MI type = IMSI
-		 * 9  first IMSI digit (BCD)
-		 *  0 second digit
-		 * 1  third
-		 * ...
-		 *  0 14th digit
-		 * 9  15th and last digit
-		 *
-		 * If the IMSI had an even number of digits:
-		 *
-		 * 08 98 10 07 00 00 10 74 f0
-		 *
-		 * 08 length for the following MI, in bytes.
-		 *  8 = 0b0001
-		 *	0 = even nr of digits
-		 *	 001 = MI type = IMSI
-		 * 9  first IMSI digit
-		 *  0 second digit
-		 * 1  third
-		 * ...
-		 *  0 14th and last digit
-		 * f  filler
-		 */
-		byte bytelen = mi[0];
-		byte mi_type = (byte)(mi[1] & 0xf);
-		boolean odd_nr_of_digits = ((mi_type & 0x08) != 0);
-		byte start_nibble = 2 + 1; // 2 to skip the bytelen, 1 to skip the mi_type
-		byte end_nibble = (byte)(2 + bytelen * 2 - (odd_nr_of_digits ? 0 : 1));
-		bcd2str(dst, dst_ofs, dst_len, mi, start_nibble, end_nibble, allow_hex);
-		return (byte)(end_nibble - start_nibble);
-	}
-
-	private byte[] str2mi(byte str[], byte mi_type)
-	{
-		/* 1 byte of MI length.
-		 * 1 nibble of mi_type.
-		 * str.length nibbles of MI BCD.
-		 * The first MI digit is in the high-nibble of the mi_type, so an odd amount of digits becomes
-		 * (1 + str.length)/2 bytes; an even amount of digits has same amount of bytes with the last
-		 * nibble unused (0xf0). */
-		byte len = (byte)(1 + (byte)(1 + str.length)/2);
-		byte mi[] = new byte[1 + len];
-		mi[0] = len;
-
-		boolean odd_digits = ((str.length & 1) != 0);
-		mi_type = (byte)(mi_type & 0x07);
-		if (odd_digits)
-			mi_type |= 0x08;
-		mi[1] = (byte)((char2bcd(str[0]) << 4) + mi_type);
-		byte str_i = 1;
-		for (byte bcd_i = 1; bcd_i < len; bcd_i++) {
-			byte data = char2bcd(str[str_i]);
-			str_i++;
-			if (str_i < str.length) {
-				data |= char2bcd(str[str_i]) << 4;
-				str_i++;
-			} else
-				data |= 0xf0;
-			mi[1 + bcd_i] = data;
-		}
-		return mi;
-	}
-
 	private byte nibble2hex(byte nibble)
 	{
 		nibble = (byte)(nibble & 0xf);
@@ -290,7 +155,7 @@ public class IMSIPseudo extends Applet implements ToolkitInterface, ToolkitConst
 
 		try {
 			byte IMSI[] = readIMSI();
-			mi2str(msg, (byte)14, (byte)16, IMSI, false);
+			MobileIdentity.mi2str(msg, (byte)14, (byte)16, IMSI, false);
 			showMsgAndWaitKey(msg);
 		} catch (SIMViewException e) {
 			showError(e.getReason());
@@ -333,8 +198,15 @@ public class IMSIPseudo extends Applet implements ToolkitInterface, ToolkitConst
 	{
 		byte[] msg = {'N', 'e', 'w', ' ', 'I', 'M', 'S', 'I', '?'};
 		byte imsi[] = prompt(msg, (short)0, (short)15);
-		byte mi[] = str2mi(imsi, MI_IMSI);
-		showMsgAndWaitKey(hexdump(mi));
+		/* The IMSI file should be 9 bytes long, even if the IMSI is shorter */
+		byte mi[];
+		try {
+			mi = MobileIdentity.str2mi(imsi, MobileIdentity.MI_IMSI, (byte)9);
+			showMsgAndWaitKey(hexdump(mi));
+		} catch (Exception e) {
+			byte err[] = {'E', 'R', 'R' };
+			showMsgAndWaitKey(err);
+		}
 	}
 
 	private byte[] readIMSI()
diff --git a/sim-applet/src/org/osmocom/IMSIPseudo/MobileIdentity.java b/sim-applet/src/org/osmocom/IMSIPseudo/MobileIdentity.java
new file mode 100644
index 0000000..e363932
--- /dev/null
+++ b/sim-applet/src/org/osmocom/IMSIPseudo/MobileIdentity.java
@@ -0,0 +1,152 @@
+/* Copyright 2020 sysmocom s.f.m.c. GmbH
+ * SPDX-License-Identifier: Apache-2.0 */
+package org.osmocom.IMSIPseudo;
+
+public class MobileIdentity {
+	public static final byte MI_IMSI = 1;
+
+	/* Convert BCD-encoded digit into printable character
+	 *  \param[in] bcd A single BCD-encoded digit
+	 *  \returns single printable character
+	 */
+	public static byte bcd2char(byte bcd)
+	{
+		if (bcd < 0xa)
+			return (byte)('0' + bcd);
+		else
+			return (byte)('A' + (bcd - 0xa));
+	}
+
+	/* Convert BCD to string.
+	 * The given nibble offsets are interpreted in BCD order, i.e. nibble 0 is bcd[0] & 0xf, nibble 1 is bcd[0] >> 4, nibble
+	 * 3 is bcd[1] & 0xf, etc..
+	 *  \param[out] dst  Output byte array.
+	 *  \param[in] dst_ofs  Where to start writing in dst.
+	 *  \param[in] dst_len  How many bytes are available at dst_ofs.
+	 *  \param[in] bcd  Binary coded data buffer.
+	 *  \param[in] start_nibble  Offset to start from, in nibbles.
+	 *  \param[in] end_nibble  Offset to stop before, in nibbles.
+	 *  \param[in] allow_hex  If false, return false if there are digits other than 0-9.
+	 *  \returns true on success, false otherwise
+	 */
+	public static boolean bcd2str(byte dst[], byte dst_ofs, byte dst_len,
+				      byte bcd[], byte start_nibble, byte end_nibble, boolean allow_hex)
+	{
+		byte nibble_i;
+		byte dst_i = dst_ofs;
+		byte dst_end = (byte)(dst_ofs + dst_len);
+		boolean rc = true;
+
+		for (nibble_i = start_nibble; nibble_i < end_nibble && dst_i < dst_end; nibble_i++, dst_i++) {
+			byte nibble = bcd[(byte)nibble_i >> 1];
+			if ((nibble_i & 1) != 0)
+				nibble >>= 4;
+			nibble &= 0xf;
+
+			if (!allow_hex && nibble > 9)
+				rc = false;
+
+			dst[dst_i] = bcd2char(nibble);
+		}
+
+		return rc;
+	}
+
+	public static byte mi2str(byte dst[], byte dst_ofs, byte dst_len,
+				  byte mi[], boolean allow_hex)
+	{
+		/* The IMSI byte array by example:
+		 * 08 99 10 07 00 00 10 74 90
+		 *
+		 * This is encoded according to 3GPP TS 24.008 10.5.1.4 Mobile
+		 * Identity, short the Mobile Identity IEI:
+		 *
+		 * 08 length for the following MI, in bytes.
+		 *  9 = 0b1001
+		 *	1 = odd nr of digits
+		 *	 001 = MI type = IMSI
+		 * 9  first IMSI digit (BCD)
+		 *  0 second digit
+		 * 1  third
+		 * ...
+		 *  0 14th digit
+		 * 9  15th and last digit
+		 *
+		 * If the IMSI had an even number of digits:
+		 *
+		 * 08 98 10 07 00 00 10 74 f0
+		 *
+		 * 08 length for the following MI, in bytes.
+		 *  8 = 0b0001
+		 *	0 = even nr of digits
+		 *	 001 = MI type = IMSI
+		 * 9  first IMSI digit
+		 *  0 second digit
+		 * 1  third
+		 * ...
+		 *  0 14th and last digit
+		 * f  filler
+		 */
+		byte bytelen = mi[0];
+		byte mi_type = (byte)(mi[1] & 0xf);
+		boolean odd_nr_of_digits = ((mi_type & 0x08) != 0);
+		byte start_nibble = 2 + 1; // 2 to skip the bytelen, 1 to skip the mi_type
+		byte end_nibble = (byte)(2 + bytelen * 2 - (odd_nr_of_digits ? 0 : 1));
+		bcd2str(dst, dst_ofs, dst_len, mi, start_nibble, end_nibble, allow_hex);
+		return (byte)(end_nibble - start_nibble);
+	}
+
+	public static byte char2bcd(byte c)
+	{
+		if (c >= '0' && c <= '9')
+			return (byte)(c - '0');
+		else if (c >= 'A' && c <= 'F')
+			return (byte)(0xa + (c - 'A'));
+		else if (c >= 'a' && c <= 'f')
+			return (byte)(0xa + (c - 'a'));
+		else
+			return 0;
+	}
+
+	public static byte[] str2mi(byte str[], byte mi_type, byte min_buflen)
+	{
+		boolean odd_digits = ((str.length & 1) != 0);
+		/* 1 nibble of mi_type.
+		 * str.length nibbles of MI BCD.
+		 */
+		byte mi_nibbles = (byte)(1 + str.length);
+		byte mi_bytes = (byte)(mi_nibbles / 2 + ((mi_nibbles & 1) != 0? 1 : 0));
+		/* 1 byte of total MI length in bytes, plus the MI nibbles */
+		byte buflen = (byte)(1 + mi_bytes);
+		/* Fill up with 0xff to the requested buffer size */
+		if (buflen < min_buflen)
+			buflen = min_buflen;
+		byte buf[] = new byte[buflen];
+
+		for (byte i = 0; i < buf.length; i++)
+			buf[i] = (byte)0xff;
+
+		/* 1 byte of following MI length in bytes */
+		buf[0] = mi_bytes;
+
+		/* first MI byte: low nibble has the MI type and odd/even indicator bit,
+		 * high nibble has the first BCD digit.
+		 */
+		mi_type = (byte)(mi_type & 0x07);
+		if (odd_digits)
+			mi_type |= 0x08;
+		buf[1] = (byte)((char2bcd(str[0]) << 4) + mi_type);
+
+		/* fill in the remaining MI nibbles */
+		byte str_i = 1;
+		for (byte mi_i = 1; mi_i < mi_bytes; mi_i++) {
+			byte data = char2bcd(str[str_i++]);
+			if (str_i < str.length)
+				data |= char2bcd(str[str_i++]) << 4;
+			else
+				data |= 0xf0;
+			buf[1 + mi_i] = data;
+		}
+		return buf;
+	}
+}
diff --git a/sim-applet/src/org/osmocom/IMSIPseudo/Test.java b/sim-applet/src/org/osmocom/IMSIPseudo/Test.java
new file mode 100644
index 0000000..3b37f26
--- /dev/null
+++ b/sim-applet/src/org/osmocom/IMSIPseudo/Test.java
@@ -0,0 +1,44 @@
+/* Copyright 2020 sysmocom s.f.m.c. GmbH
+ * SPDX-License-Identifier: Apache-2.0 */
+package org.osmocom.IMSIPseudo;
+import org.osmocom.IMSIPseudo.*;
+
+public class Test {
+	private static byte nibble2hex(byte nibble)
+	{
+		nibble = (byte)(nibble & 0xf);
+		if (nibble < 0xa)
+			return (byte)('0' + nibble);
+		else
+			return (byte)('a' + nibble - 0xa);
+	}
+
+	private static byte[] hexdump(byte data[])
+	{
+		byte res[] = new byte[(byte)(data.length*2)];
+		for (byte i = 0; i < data.length; i++) {
+			res[(byte)(i*2)] = nibble2hex((byte)(data[i] >> 4));
+			res[(byte)(i*2 + 1)] = nibble2hex(data[i]);
+		}
+		return res;
+	}
+
+	private static String hexdumpStr(byte data[])
+	{
+		return new String(hexdump(data));
+	}
+
+	public static void main(String args[]){
+		System.out.println(hexdumpStr(MobileIdentity.str2mi("123456".getBytes(), (byte)1, (byte)9)));
+		System.out.println(hexdumpStr(MobileIdentity.str2mi("1234567".getBytes(), (byte)1, (byte)9)));
+		System.out.println(hexdumpStr(MobileIdentity.str2mi("12345678".getBytes(), (byte)1, (byte)9)));
+		System.out.println(hexdumpStr(MobileIdentity.str2mi("123456789".getBytes(), (byte)1, (byte)9)));
+		System.out.println(hexdumpStr(MobileIdentity.str2mi("1234567890".getBytes(), (byte)1, (byte)9)));
+		System.out.println(hexdumpStr(MobileIdentity.str2mi("12345678901".getBytes(), (byte)1, (byte)9)));
+		System.out.println(hexdumpStr(MobileIdentity.str2mi("123456789012".getBytes(), (byte)1, (byte)9)));
+		System.out.println(hexdumpStr(MobileIdentity.str2mi("1234567890123".getBytes(), (byte)1, (byte)9)));
+		System.out.println(hexdumpStr(MobileIdentity.str2mi("12345678901234".getBytes(), (byte)1, (byte)9)));
+		System.out.println(hexdumpStr(MobileIdentity.str2mi("123456789012345".getBytes(), (byte)1, (byte)9)));
+		System.out.println(hexdumpStr(MobileIdentity.str2mi("1234567890123456".getBytes(), (byte)1, (byte)9)));
+	}
+}