From 8f1c94724cd51154b09bb8ff72f48b9838024ea0 Mon Sep 17 00:00:00 2001
From: Qasim Ayyaz Khan <qasimakhan@gmail.com>
Date: Thu, 2 Jun 2016 23:52:25 -0400
Subject: [PATCH] Fixed extraction of UDH header from original buffer rather
 than from encoded message as CSMS reference / values number greater than 0x7F
 were not decoded properly.

---
 lib/session.js | 16 ++++------------
 lib/utils.js   | 25 +++++++++++++++++++++++--
 2 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/lib/session.js b/lib/session.js
index 9933c41..1ae34b8 100644
--- a/lib/session.js
+++ b/lib/session.js
@@ -368,18 +368,10 @@ function longSms(pduObj) {
 	//      reference number is of one octet otherwise it consists of 2 octets. Other fields can
 	//	be found from below reference.
 	//      reference: https://en.wikipedia.org/wiki/Concatenated_SMS
-	var encodedMessage = utils.encodeMsg(pduObj.params.short_message),
-            udhSize = encodedMessage[0];
-	var smsGroupId, smsParts, partNr;
-        if(udhSize === 0x05) {
-                smsGroupId = encodedMessage[3],
-                smsParts   = encodedMessage[4],
-                partNr     = encodedMessage[5];
-        } else {
-                smsGroupId = (encodedMessage[3] * 256) + encodedMessage[4],
-                smsParts   = encodedMessage[5],
-                partNr     = encodedMessage[6];
-        }
+        var udhSize = pduObj.params['udhHeader'].size,
+	    smsGroupId = pduObj.params['udhHeader'].reference, 
+	    smsParts = pduObj.params['udhHeader'].totalParts,
+	    partNr = pduObj.params['udhHeader'].partNr;
 
 	var longSmsId  = pduObj.params.source_addr + '_' + pduObj.params.destination_addr + '_' + smsGroupId;
 
diff --git a/lib/utils.js b/lib/utils.js
index f806205..d0aebb5 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -271,8 +271,29 @@ function pduToObj(pdu, stupidNullByte, callback) {
 			paramSize            = command.params[param].type.size(retObj.params[param]);
 
 			log.silly('larvitsmpp: lib/utils.js: pduToObj() - Reading param "' + param + '" at offset ' + offset + ' with calculated size: ' + paramSize + ' content in hex: ' + pdu.slice(offset, offset + paramSize).toString('hex'));
-
 			if (param === 'short_message') {
+				if((retObj.params['esm_class'] & 0x40) === 0x40) {
+					//This is a part of long sms. We should save UDH header information in params.
+					console.log(pdu.slice(offset, offset + paramSize).toString('hex').slice(6, 8))
+					var hsize = parseInt("0x" + pdu.slice(offset, offset + paramSize).toString('hex').slice(0, 2));
+					//If hsize is >5 then CSMS Reference consist of two parts
+					if(hsize == 5) {
+						var reference = parseInt("0x" + pdu.slice(offset, offset + paramSize).toString('hex').slice(6, 8)),
+						    totalParts = parseInt("0x" + pdu.slice(offset, offset + paramSize).toString('hex').slice(8, 10)),
+						    partNr = parseInt("0x" + pdu.slice(offset, offset + paramSize).toString('hex').slice(10, 12));
+					} else {
+						var reference = (parseInt("0x" + pdu.slice(offset, offset + paramSize).toString('hex').slice(6, 8)) * 256) + parseInt("0x" + pdu.slice(offset, offset + paramSize).toString('hex').slice(8, 10)),
+						    totalParts = parseInt("0x" + pdu.slice(offset, offset + paramSize).toString('hex').slice(10, 12)),
+						    partNr = parseInt("0x" + pdu.slice(offset, offset + paramSize).toString('hex').slice(12, 14));
+					}
+					var udhHeader = {
+						'size': hsize,
+						'reference': reference,
+						'totalParts': totalParts,
+						'partNr': partNr
+					}
+					retObj.params['udhHeader'] = udhHeader;
+				}
 				// Check if we have a trailing NULL octet after the short_message. Some idiot thought that would be a good idea
 				// in some implementations, so we need to account for that.
 				if (stupidNullByte === true) {
@@ -782,4 +803,4 @@ exports.pduReturn = pduReturn;
 exports.smppDate  = smppDate;
 exports.bitCount  = bitCount;
 exports.splitMsg  = splitMsg;
-exports.smsDlr    = smsDlr;
\ No newline at end of file
+exports.smsDlr    = smsDlr;