MME2 changes - Propped commits from openmme/paging branch. Added scripts
for code gen

Change-Id: Ie55032217232214ac8544ca76ea34335205329e4
diff --git a/src/s6a/Makefile b/src/s6a/Makefile
new file mode 100644
index 0000000..a5fb2c9
--- /dev/null
+++ b/src/s6a/Makefile
@@ -0,0 +1,77 @@
+#
+# Copyright (c) 2003-2018, Great Software Laboratory Pvt. Ltd.
+# Copyright (c) 2017 Intel Corporation
+# Copyright (c) 2019, Infosys Ltd.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+#SRCDIR := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
+include ../../Makefile.common
+
+LIB_PATH +=-L../common/
+
+SRCDIR := .
+TARGET := $(BINDIR)/s6a-app
+
+SRCEXT := c
+
+SOURCES := $(shell find $(SRCDIR) -type f -name '*.$(SRCEXT)')
+
+OBJECTS := $(patsubst $(SRCDIR)/%,$(OBJDIR)/s6a/%,$(SOURCES:.$(SRCEXT)=.o))
+
+CFLAGS += -Wall
+
+ifeq ($(DEBUG),true)
+	CFLAGS += -g
+endif
+
+ifeq ($(DEBUG),false)
+#	CFLAGS += -O3
+endif
+
+
+LIBS :=  \
+	-linterface \
+	-llog \
+	-lthreadpool \
+	-ljson \
+	-lpthread \
+	-lfdproto \
+	-lfdcore
+
+$(TARGET): $(OBJECTS)
+	@echo " Linking..."
+	@mkdir -p $(BINDIR)
+	$(CC) $(LFLAGS) $^ -o $(TARGET) $(LIB_PATH) $(LIBS)
+
+$(OBJDIR)/s6a/%.o: $(SRCDIR)/%.$(SRCEXT)
+	@mkdir -p $(OBJDIR)/s6a/handlers
+	$(CC) $(CFLAGS) $(INC_DIRS) -c -o $@ $<
+
+all:$(TARGET)
+
+clean:
+	@echo " Cleaning...";
+	@rm  -rf $(OBJDIR)/s6a $(TARGET)
+
+install:
+	@mkdir -p $(TARGET_DIR)/bin
+	-@cp $(TARGET) $(TARGET_DIR)/bin
+	-@mkdir -p $(TARGET_DIR)/conf
+	-@cp conf/s6a_fd.conf $(TARGET_DIR)/conf/s6a_fd.conf
+	-@cp conf/s6a.json $(TARGET_DIR)/conf/s6a.json
+	-@cp conf/make_certs.sh $(TARGET_DIR)/conf/make_certs.sh
+
+.PHONY: clean
+
diff --git a/src/s6a/conf/01.pem b/src/s6a/conf/01.pem
new file mode 100644
index 0000000..95d0f48
--- /dev/null
+++ b/src/s6a/conf/01.pem
@@ -0,0 +1,60 @@
+Certificate:
+    Data:
+        Version: 3 (0x2)
+        Serial Number: 1 (0x1)
+        Signature Algorithm: sha256WithRSAEncryption
+        Issuer: CN=ca.localdomain, C=FR, ST=BdR, L=Aix, O=fD, OU=Tests
+        Validity
+            Not Before: Sep  2 12:10:16 2019 GMT
+            Not After : Sep  1 12:10:16 2020 GMT
+        Subject: C=FR, ST=BdR, O=fD, OU=Tests, CN=mme.localdomain
+        Subject Public Key Info:
+            Public Key Algorithm: rsaEncryption
+                RSA Public-Key: (1024 bit)
+                Modulus:
+                    00:c9:b1:bf:1e:0c:c1:6e:13:5f:5b:0a:39:f4:46:
+                    10:f6:87:70:b9:4a:34:63:01:fc:12:cb:eb:94:df:
+                    bd:24:9e:47:58:8b:90:a7:97:3a:91:cf:51:11:f6:
+                    d2:37:ce:b9:98:d0:c6:11:9d:41:a1:6b:31:13:29:
+                    dc:58:4e:24:a9:6a:5d:74:76:20:e9:cb:b1:22:f9:
+                    e5:9a:89:6f:3f:0b:c2:31:ae:9f:4b:79:2f:d6:c4:
+                    42:1c:5b:15:6d:d8:9c:61:49:8c:14:40:cc:88:0e:
+                    f7:1e:24:97:65:2d:5d:1f:fb:7d:5f:b1:19:95:3b:
+                    08:a7:e8:98:06:14:30:0c:c5
+                Exponent: 65537 (0x10001)
+        X509v3 extensions:
+            X509v3 Basic Constraints: 
+                CA:FALSE
+            Netscape Comment: 
+                OpenSSL Generated Certificate
+            X509v3 Subject Key Identifier: 
+                BD:1E:A7:62:7F:A7:ED:01:2C:CF:B7:B8:31:10:BD:73:FC:AA:8D:50
+            X509v3 Authority Key Identifier: 
+                keyid:E8:D3:89:BA:7B:C0:17:0A:CA:F6:15:AB:20:0F:FE:E0:78:42:8C:33
+
+    Signature Algorithm: sha256WithRSAEncryption
+         02:87:6c:ba:bf:4c:d2:a5:1a:de:84:07:fe:1e:56:0b:cd:8b:
+         6c:73:c9:22:5b:bc:97:55:72:3d:66:89:3a:49:5d:62:c2:71:
+         4f:f2:51:42:3c:2c:8a:31:8d:90:43:56:d0:12:db:d1:ce:1c:
+         55:60:ee:85:8f:7b:a8:1e:b1:bf:59:65:a1:d8:a4:7d:34:d9:
+         95:d3:62:96:59:d2:06:8d:84:73:8a:d9:9a:7a:52:fa:f5:7f:
+         7e:41:5e:7c:9e:08:fd:58:ac:b9:f4:42:46:be:3f:2b:df:57:
+         84:ad:38:50:e8:34:95:71:31:6a:70:15:f1:02:27:57:57:45:
+         1c:e7
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/src/s6a/conf/cacert.pem b/src/s6a/conf/cacert.pem
new file mode 100644
index 0000000..b6dc142
--- /dev/null
+++ b/src/s6a/conf/cacert.pem
@@ -0,0 +1,16 @@
+-----BEGIN CERTIFICATE-----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==
+-----END CERTIFICATE-----
diff --git a/src/s6a/conf/cakey.pem b/src/s6a/conf/cakey.pem
new file mode 100644
index 0000000..a9418c5
--- /dev/null
+++ b/src/s6a/conf/cakey.pem
@@ -0,0 +1,16 @@
+-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----
diff --git a/src/s6a/conf/demoCA/index.txt b/src/s6a/conf/demoCA/index.txt
new file mode 100644
index 0000000..c70d812
--- /dev/null
+++ b/src/s6a/conf/demoCA/index.txt
@@ -0,0 +1 @@
+V	200901121016Z		01	unknown	/C=FR/ST=BdR/O=fD/OU=Tests/CN=mme.localdomain
diff --git a/src/s6a/conf/demoCA/index.txt.attr b/src/s6a/conf/demoCA/index.txt.attr
new file mode 100644
index 0000000..8f7e63a
--- /dev/null
+++ b/src/s6a/conf/demoCA/index.txt.attr
@@ -0,0 +1 @@
+unique_subject = yes
diff --git a/src/s6a/conf/demoCA/index.txt.old b/src/s6a/conf/demoCA/index.txt.old
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/src/s6a/conf/demoCA/index.txt.old
diff --git a/src/s6a/conf/demoCA/serial b/src/s6a/conf/demoCA/serial
new file mode 100644
index 0000000..9e22bcb
--- /dev/null
+++ b/src/s6a/conf/demoCA/serial
@@ -0,0 +1 @@
+02
diff --git a/src/s6a/conf/demoCA/serial.old b/src/s6a/conf/demoCA/serial.old
new file mode 100644
index 0000000..8a0f05e
--- /dev/null
+++ b/src/s6a/conf/demoCA/serial.old
@@ -0,0 +1 @@
+01
diff --git a/src/s6a/conf/make_certs.sh b/src/s6a/conf/make_certs.sh
new file mode 100644
index 0000000..ff78b8f
--- /dev/null
+++ b/src/s6a/conf/make_certs.sh
@@ -0,0 +1,32 @@
+#! /bin/bash
+
+#Copyright (c) 2017 Sprint
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+rm -rf demoCA
+mkdir demoCA
+echo 01 > demoCA/serial
+touch demoCA/index.txt
+
+HOST=$1
+DOMAIN=$2
+
+# CA self certificate
+openssl req  -new -batch -x509 -days 3650 -nodes -newkey rsa:1024 -out cacert.pem -keyout cakey.pem -subj /CN=ca.localdomain/C=FR/ST=BdR/L=Aix/O=fD/OU=Tests
+
+#
+openssl genrsa -out $HOST.key.pem 1024
+openssl req -new -batch -out $HOST.csr.pem -key $HOST.key.pem -subj /CN=$HOST.$DOMAIN/C=FR/ST=BdR/L=Aix/O=fD/OU=Tests
+openssl ca -cert cacert.pem -keyfile cakey.pem -in $HOST.csr.pem -out $HOST.cert.pem -outdir . -batch
+
diff --git a/src/s6a/conf/mme.cert.pem b/src/s6a/conf/mme.cert.pem
new file mode 100644
index 0000000..95d0f48
--- /dev/null
+++ b/src/s6a/conf/mme.cert.pem
@@ -0,0 +1,60 @@
+Certificate:
+    Data:
+        Version: 3 (0x2)
+        Serial Number: 1 (0x1)
+        Signature Algorithm: sha256WithRSAEncryption
+        Issuer: CN=ca.localdomain, C=FR, ST=BdR, L=Aix, O=fD, OU=Tests
+        Validity
+            Not Before: Sep  2 12:10:16 2019 GMT
+            Not After : Sep  1 12:10:16 2020 GMT
+        Subject: C=FR, ST=BdR, O=fD, OU=Tests, CN=mme.localdomain
+        Subject Public Key Info:
+            Public Key Algorithm: rsaEncryption
+                RSA Public-Key: (1024 bit)
+                Modulus:
+                    00:c9:b1:bf:1e:0c:c1:6e:13:5f:5b:0a:39:f4:46:
+                    10:f6:87:70:b9:4a:34:63:01:fc:12:cb:eb:94:df:
+                    bd:24:9e:47:58:8b:90:a7:97:3a:91:cf:51:11:f6:
+                    d2:37:ce:b9:98:d0:c6:11:9d:41:a1:6b:31:13:29:
+                    dc:58:4e:24:a9:6a:5d:74:76:20:e9:cb:b1:22:f9:
+                    e5:9a:89:6f:3f:0b:c2:31:ae:9f:4b:79:2f:d6:c4:
+                    42:1c:5b:15:6d:d8:9c:61:49:8c:14:40:cc:88:0e:
+                    f7:1e:24:97:65:2d:5d:1f:fb:7d:5f:b1:19:95:3b:
+                    08:a7:e8:98:06:14:30:0c:c5
+                Exponent: 65537 (0x10001)
+        X509v3 extensions:
+            X509v3 Basic Constraints: 
+                CA:FALSE
+            Netscape Comment: 
+                OpenSSL Generated Certificate
+            X509v3 Subject Key Identifier: 
+                BD:1E:A7:62:7F:A7:ED:01:2C:CF:B7:B8:31:10:BD:73:FC:AA:8D:50
+            X509v3 Authority Key Identifier: 
+                keyid:E8:D3:89:BA:7B:C0:17:0A:CA:F6:15:AB:20:0F:FE:E0:78:42:8C:33
+
+    Signature Algorithm: sha256WithRSAEncryption
+         02:87:6c:ba:bf:4c:d2:a5:1a:de:84:07:fe:1e:56:0b:cd:8b:
+         6c:73:c9:22:5b:bc:97:55:72:3d:66:89:3a:49:5d:62:c2:71:
+         4f:f2:51:42:3c:2c:8a:31:8d:90:43:56:d0:12:db:d1:ce:1c:
+         55:60:ee:85:8f:7b:a8:1e:b1:bf:59:65:a1:d8:a4:7d:34:d9:
+         95:d3:62:96:59:d2:06:8d:84:73:8a:d9:9a:7a:52:fa:f5:7f:
+         7e:41:5e:7c:9e:08:fd:58:ac:b9:f4:42:46:be:3f:2b:df:57:
+         84:ad:38:50:e8:34:95:71:31:6a:70:15:f1:02:27:57:57:45:
+         1c:e7
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/src/s6a/conf/mme.csr.pem b/src/s6a/conf/mme.csr.pem
new file mode 100644
index 0000000..cbe6c05
--- /dev/null
+++ b/src/s6a/conf/mme.csr.pem
@@ -0,0 +1,11 @@
+-----BEGIN CERTIFICATE REQUEST-----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+-----END CERTIFICATE REQUEST-----
diff --git a/src/s6a/conf/mme.key.pem b/src/s6a/conf/mme.key.pem
new file mode 100644
index 0000000..5a4b72a
--- /dev/null
+++ b/src/s6a/conf/mme.key.pem
@@ -0,0 +1,15 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIICXAIBAAKBgQDJsb8eDMFuE19bCjn0RhD2h3C5SjRjAfwSy+uU370knkdYi5Cn
+lzqRz1ER9tI3zrmY0MYRnUGhazETKdxYTiSpal10diDpy7Ei+eWaiW8/C8Ixrp9L
+eS/WxEIcWxVt2JxhSYwUQMyIDvceJJdlLV0f+31fsRmVOwin6JgGFDAMxQIDAQAB
+AoGAIrcFPhbT9C5Ba1oHP5QPt174d+vduGzPBi0zDxyzYWocvZDIBRBydEZKndzt
+sc1TBIpqjP2UHkRk3feGhWxtwqyQLUlzn3KajgzJjy/gMLicNi/oRtPi/olCQvZw
+57K5pFHIn8E0RMCaDqirpRuwTOIfcsI1Pw/ndykDC2Q+8AECQQD456teQsq7EuLT
+HpY3hkqvDXh4VWptGLqhTvTQFo2hazZYDhjIn0k6wSeeMgnATMP7ZSTcSy043Nie
+Zxzvh74FAkEAz3GRUThWHjCSxr2qxzZJIfM1H89ax5nHQFgwD3Jj8isyrDSY1zkX
+3VDZxswrsNg+iFkeG27gcpciEgn09fGPwQJAMjw3pwed+RG/u9JhiQVOj3QNi2PZ
+3fjuud3ApTrYDOshhbYapGsZkYUoZNI+i5QyvctVHC0EDITuJ1IyUdm4rQJBAMjm
+pePQ+aY3SI7tNS3FZ0JX9gUenj5csdmhDrqHAECSkXqxXaxigLg4CxE6vr2AT99g
+34WV9g1ETRzHQ9PE5IECQCiFVkVT/G4AHBKnm1/W+At76Ks4bWXPhh6TzQAse77T
+FmSRWdQL09qj2rOeArqc8Q5pOVLgc0YY0Ny9gMA+3/c=
+-----END RSA PRIVATE KEY-----
diff --git a/src/s6a/conf/s6a.json b/src/s6a/conf/s6a.json
new file mode 100644
index 0000000..6511ee8
--- /dev/null
+++ b/src/s6a/conf/s6a.json
@@ -0,0 +1,37 @@
+{
+	"mme": {
+		"ip_addr": "192.168.1.55",
+		"name": "vmmestandalone",
+		"group_id": 1,
+		"code": 1,
+		"__comment__": "Here is comment",
+		"mcc": {
+			"dig1": 2,
+			"dig2": 0,
+			"dig3": 8
+		},
+		"mnc": {
+			"dig1": 0,
+			"dig2": 1,
+			"dig3": -1
+		}
+	},
+	"s1ap": {
+		"s1ap_local_addr": "127.0.0.1",
+		"sctp_port": 36412,
+		"enb_addr": "127.0.0.1",
+		"enb_port": 5003,
+		"egtp_default_hostname": "sutlej.ccin.ccpu.com"
+	},
+	"s11": {
+		"egtp_local_addr": "192.168.1.55",
+		"egtp_default_port": 2123,
+		"sgw_addr": "127.0.0.1",
+		"pgw_addr": "192.168.1.105"
+	},
+	"s6a": {
+		"hss_type": "freediameter",
+		"host_name": "hss.openair4G.eur",
+		"realm": "openair4G.eur"
+	}
+}
diff --git a/src/s6a/conf/s6a_fd.conf b/src/s6a/conf/s6a_fd.conf
new file mode 100644
index 0000000..92f04f6
--- /dev/null
+++ b/src/s6a/conf/s6a_fd.conf
@@ -0,0 +1,80 @@
+
+# -------- Test configuration ---------
+AppServThreads = 40;
+SCTP_streams = 3;
+NoRelay;
+No_IPv6;
+#SCTP_streams = 3;
+
+# Identity = "<diameter_host>.<diameter_realm>";
+Identity = "mme.localdomain";
+Realm = "localdomain";
+Port = 38698;
+SecPort = 38699;
+
+ConnectPeer = "hss.openair4G.eur" { ConnectTo = "192.168.1.55"; No_TLS; port = 3868; };
+
+# TLS_Cred = "<diameter_host>.cert.pem", "<diameter_host>.key.pem";
+TLS_Cred = "conf/mme.cert.pem",
+	   "conf/mme.key.pem";
+TLS_CA = "conf/cacert.pem";
+
+LoadExtension = "/usr/local/lib/freeDiameter/dict_3gpp2_avps.fdx";
+#LoadExtension = "/usr/local/lib/freeDiameter/dict_CreditControl.fdx";
+#LoadExtension = "/usr/local/lib/freeDiameter/dict_base_rfc6733.fdx";
+###
+LoadExtension = "/usr/local/lib/freeDiameter/dict_draftload_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_etsi283034_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_rfc4004_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_rfc4006bis_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_rfc4072_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_rfc4590_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_rfc5447_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_rfc5580_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_rfc5777_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_rfc5778_avps.fdx";
+###
+LoadExtension = "/usr/local/lib/freeDiameter/dict_rfc6734_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_rfc6942_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_rfc7155_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_rfc7683_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_rfc7944_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29061_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29128_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29154_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29173_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29212_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29214_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29215_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29217_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29229_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29272_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29273_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29329_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29336_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29337_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29338_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29343_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29344_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29345_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29368_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts29468_avps.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_ts32299_avps.fdx";
+#LoadExtension = "/usr/local/lib/freeDiameter/dict_CxDx.fdx";
+#LoadExtension = "/usr/local/lib/freeDiameter/dict_Gx.fdx";
+#LoadExtension = "/usr/local/lib/freeDiameter/dict_NAS.fdx";
+#LoadExtension = "/usr/local/lib/freeDiameter/dict_Rf.fdx";
+#LoadExtension = "/usr/local/lib/freeDiameter/dict_Ro.fdx";
+#LoadExtension = "/usr/local/lib/freeDiameter/dict_Rx.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_S6as6d.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_S6c.fdx";
+#LoadExtension = "/usr/local/lib/freeDiameter/dict_S6mS6n.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_S6t.fdx";
+#LoadExtension = "/usr/local/lib/freeDiameter/dict_S9.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_SGd.fdx";
+#LoadExtension = "/usr/local/lib/freeDiameter/dict_SLh.fdx";
+#LoadExtension = "/usr/local/lib/freeDiameter/dict_Sd.fdx";
+#LoadExtension = "/usr/local/lib/freeDiameter/dict_Sh.fdx";
+#LoadExtension = "/usr/local/lib/freeDiameter/dict_T4.fdx";
+LoadExtension = "/usr/local/lib/freeDiameter/dict_T6aT6bT7.fdx";
+#LoadExtension = "/usr/local/lib/freeDiameter/dict_Tsp.fdx";
diff --git a/src/s6a/fd_init.c b/src/s6a/fd_init.c
new file mode 100644
index 0000000..b93623f
--- /dev/null
+++ b/src/s6a/fd_init.c
@@ -0,0 +1,656 @@
+/*
+ * Copyright (c) 2003-2018, Great Software Laboratory Pvt. Ltd.
+ * Copyright (c) 2017 Intel Corporation
+ * Copyright (c) 2019, Infosys Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *	   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <freeDiameter/freeDiameter-host.h>
+#include <freeDiameter/libfdcore.h>
+#include <freeDiameter/libfdproto.h>
+
+#include "log.h"
+#include "s6a.h"
+#include "s6a_fd.h"
+
+/**Globals and externs**/
+extern struct fd_dict_objects g_fd_dict_objs;
+extern struct fd_dict_data g_fd_dict_data;
+extern bool g_nolog;
+extern enum log_levels g_log_level;
+/**Globals and externs**/
+
+/**
+ * @brief Add element to freediameter message
+ * ready
+ * @param[in] val - AVP value to be added
+ * @param[in] obj - Disctionary object
+ * @param[in/out] msg_bufi
+ * @return int Sucess or failure code
+ */
+int
+add_fd_msg(union avp_value *val, struct dict_object * obj,
+		struct msg **msg_buf)
+{
+	struct avp *avp_val = NULL;
+
+	CHECK_FCT_DO(fd_msg_avp_new(obj, 0, &avp_val), return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_msg_avp_setvalue(avp_val, val), return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_msg_avp_add(*msg_buf, MSG_BRW_LAST_CHILD, avp_val),
+				return S6A_FD_ERROR);
+
+	return SUCCESS;
+}
+
+/**
+ * @brief Dumo freediameter message buffer
+ * ready
+ * @param[in] Freediameter message to print
+ * @return void
+ */
+void
+dump_fd_msg(struct msg *msg)
+{
+	//char *buf = NULL;
+	//int len = 0;
+
+	g_nolog = true;
+
+	if (g_nolog) return;
+
+	//TODO: correct - fprintf(stderr, "%s\n", fd_msg_dump_treeview(&buf, &len, NULL, msg,
+	//			fd_g_config->cnf_dict, 0, 1));
+	//free(buf);
+}
+
+/**
+ * @brief Extract last integeger representing ue index from session ID
+ * @param[in] sid - session id
+ * @param[in] sidlen - session id len
+ * @return int - eror code
+ */
+int
+get_ue_idx_from_fd_resp(unsigned char *sid, int sidlen)
+{
+	int index = -1;
+	char *tmp = strrchr((char *)sid, ';');
+
+	index = strtol(++tmp, NULL, 10);
+	log_msg(LOG_INFO, "Received resp for index %d\n", index);
+	return index;
+}
+
+/**
+ * @brief Initialize free diameter vendor info
+ * @param None
+ * @return int - eror code
+ */
+int
+s6a_fd_init()
+{
+	//TODO: check vendor id
+	vendor_id_t vendor_id = 10415;
+
+	FD_DICT_SEARCH(DICT_VENDOR, VENDOR_BY_ID, &vendor_id, g_fd_dict_objs.vendor_id);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.vendor_id, &g_fd_dict_data.vendor_data),
+		return S6A_FD_ERROR);
+
+	return SUCCESS;
+}
+
+/**
+ * @brief Initialize freediameter dictionary objects
+ * @param None
+ * @return int - error code
+ */
+int
+s6a_fd_objs_init()
+{
+	//TODO: Check app id
+	application_id_t app_s6a = 16777251;
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME, "Result-Code",
+			g_fd_dict_objs.res_code);
+
+	FD_DICT_SEARCH(DICT_APPLICATION, APPLICATION_BY_ID, &app_s6a,
+			g_fd_dict_objs.s6a_app);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME, "Experimental-Result",
+					g_fd_dict_objs.exp_res);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME, "Auth-Application-Id",
+					g_fd_dict_objs.auth_app_id);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME, "Session-Id",
+					g_fd_dict_objs.sess_id);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME, "Auth-Session-State",
+					g_fd_dict_objs.auth_sess_state);
+
+	//NI Detach
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME, "Origin-Host",
+					g_fd_dict_objs.org_host);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME, "Origin-Realm",
+					g_fd_dict_objs.org_realm);
+	//NI Detach
+	
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME, "Destination-Host",
+					g_fd_dict_objs.dest_host);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME, "Destination-Realm",
+					g_fd_dict_objs.dest_realm);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME, "User-Name",
+					g_fd_dict_objs.user_name);
+
+	/*search and map avp names to elements*/
+	FD_DICT_SEARCH(DICT_COMMAND, CMD_BY_NAME,
+					"Authentication-Information-Request",
+					g_fd_dict_objs.AIR);
+
+	FD_DICT_SEARCH(DICT_COMMAND, CMD_BY_NAME,
+					"Authentication-Information-Answer",
+					g_fd_dict_objs.AIA);
+
+	FD_DICT_SEARCH(DICT_COMMAND, CMD_BY_NAME, "Update-Location-Request",
+				g_fd_dict_objs.ULR);
+
+	FD_DICT_SEARCH(DICT_COMMAND, CMD_BY_NAME, "Update-Location-Answer",
+					g_fd_dict_objs.ULA);
+
+	FD_DICT_SEARCH(DICT_COMMAND, CMD_BY_NAME, "Purge-UE-Request",
+					g_fd_dict_objs.PUR);
+
+	FD_DICT_SEARCH(DICT_COMMAND, CMD_BY_NAME, "Purge-UE-Answer",
+					g_fd_dict_objs.PUA);
+	
+	//NI Detach
+	FD_DICT_SEARCH(DICT_COMMAND, CMD_BY_NAME, "Cancel-Location-Request",
+					g_fd_dict_objs.CLR);
+
+	FD_DICT_SEARCH(DICT_COMMAND, CMD_BY_NAME, "Cancel-Location-Answer",
+					g_fd_dict_objs.CLA);
+	//NI Detach
+	
+	
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "Visited-PLMN-Id",
+					g_fd_dict_objs.visited_PLMN_id);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS,
+					"Requested-EUTRAN-Authentication-Info",
+					g_fd_dict_objs.req_EUTRAN_auth_info);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS,
+					"Number-Of-Requested-Vectors",
+					g_fd_dict_objs.no_of_req_vectors);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS,
+					"Immediate-Response-Preferred",
+					g_fd_dict_objs.immediate_resp_pref);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "Authentication-Info",
+					g_fd_dict_objs.auth_info);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "E-UTRAN-Vector",
+					g_fd_dict_objs.E_UTRAN_vector);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "RAND",
+					g_fd_dict_objs.RAND);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "XRES",
+					g_fd_dict_objs.XRES);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "AUTN",
+					g_fd_dict_objs.AUTN);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "KASME",
+					g_fd_dict_objs.KASME);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "RAT-Type",
+					g_fd_dict_objs.RAT_type);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "ULR-Flags",
+					g_fd_dict_objs.ULR_flags);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "ULA-Flags",
+					g_fd_dict_objs.ULA_flags);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "Subscription-Data",
+					g_fd_dict_objs.subscription_data);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "Subscriber-Status",
+					g_fd_dict_objs.subscriber_status);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "MSISDN",
+					g_fd_dict_objs.MSISDN);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "Network-Access-Mode",
+					g_fd_dict_objs.net_access_mode);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS,
+					"Access-Restriction-Data",
+					g_fd_dict_objs.access_restriction_data);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "AMBR",
+					g_fd_dict_objs.AMBR);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS,
+					"Max-Requested-Bandwidth-UL",
+					g_fd_dict_objs.max_req_bandwidth_UL);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS,
+					"Max-Requested-Bandwidth-DL",
+					g_fd_dict_objs.max_req_bandwidth_DL);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS,
+					"APN-Configuration-Profile",
+					g_fd_dict_objs.APN_config_profile);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "Context-Identifier",
+					g_fd_dict_objs.ctx_id);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS,
+					"Additional-Context-Identifier",
+					g_fd_dict_objs.additional_ctx_id);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS,
+					"All-APN-Configurations-Included-Indicator",
+					g_fd_dict_objs.all_APN_configs_included_ind);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "APN-Configuration",
+					g_fd_dict_objs.APN_config);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "PDN-Type",
+					g_fd_dict_objs.PDN_type);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS,
+					"PDN-GW-Allocation-Type",
+					g_fd_dict_objs.PDN_GW_alloc_type);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "Specific-APN-Info",
+					g_fd_dict_objs.specific_APN_info);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS,
+					"Non-IP-PDN-Type-Indicator",
+					g_fd_dict_objs.non_IP_PDN_type_ind);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS,
+					"Non-IP-Data-Delivery-Mechanism",
+					g_fd_dict_objs.non_IP_data_delivery_mech);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "SCEF-ID",
+					g_fd_dict_objs.SCEF_ID);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "Priority-Level",
+					g_fd_dict_objs.priority_Level);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "Location-Area-Identity",
+					g_fd_dict_objs.location_area_id);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "Tracking-Area-Identity",
+					g_fd_dict_objs.tracking_area_id);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS,
+					"Subscribed-Periodic-RAU-TAU-Timer",
+					g_fd_dict_objs.subsc_periodic_RAU_TAU_tmr);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS, "PUR-Flags",
+					g_fd_dict_objs.PUR_flags);
+
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS,
+					"Regional-Subscription-Zone-Code",
+					g_fd_dict_objs.reg_subs_zone_code);
+	//NI Detach
+	FD_DICT_SEARCH(DICT_AVP, AVP_BY_NAME_ALL_VENDORS,
+					"Cancellation-Type",
+					g_fd_dict_objs.cancellation_type);
+	return SUCCESS;
+}
+
+/**
+ * @brief Initialize freediameter data objects for the dictionary object
+ * initialized
+ * @param None
+ * @return int - error code
+ */
+int
+s6a_fd_data_init()
+{
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.s6a_app,
+				&g_fd_dict_data.app_s6a_data), return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.res_code,
+				&g_fd_dict_data.res_code), return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.exp_res,
+				&g_fd_dict_data.exp_res), return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.auth_app_id,
+			&g_fd_dict_data.auth_app_id),
+			return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.sess_id,
+				&g_fd_dict_data.sess_id), return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.auth_sess_state,
+			&g_fd_dict_data.auth_sess_state),
+			return S6A_FD_ERROR);
+	//NI Detach
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.org_host,
+				&g_fd_dict_data.org_host), return S6A_FD_ERROR);
+	
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.org_realm,
+				&g_fd_dict_data.org_realm), return S6A_FD_ERROR);
+	//NI Detach
+	
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.dest_host,
+				&g_fd_dict_data.dest_host), return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.dest_realm,
+				&g_fd_dict_data.dest_realm), return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.user_name,
+				&g_fd_dict_data.user_name), return S6A_FD_ERROR);
+	
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.visited_PLMN_id,
+				&g_fd_dict_data.visited_PLMN_id),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.req_EUTRAN_auth_info,
+				&g_fd_dict_data.req_EUTRAN_auth_info),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.no_of_req_vectors,
+				&g_fd_dict_data.no_of_req_vectors),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.immediate_resp_pref,
+				&g_fd_dict_data.immediate_resp_pref),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.auth_info,
+				&g_fd_dict_data.auth_info),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.E_UTRAN_vector,
+				&g_fd_dict_data.E_UTRAN_vector),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.RAND,
+				&g_fd_dict_data.RAND),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.XRES,
+				&g_fd_dict_data.XRES),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.AUTN,
+				&g_fd_dict_data.AUTN),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.KASME,
+				&g_fd_dict_data.KASME),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.RAT_type,
+				&g_fd_dict_data.RAT_type),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.ULR_flags,
+				&g_fd_dict_data.ULR_flags),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.ULA_flags,
+				&g_fd_dict_data.ULA_flags),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.subscription_data,
+				&g_fd_dict_data.subscription_data),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.subscriber_status,
+				&g_fd_dict_data.subscriber_status),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.MSISDN,
+				&g_fd_dict_data.MSISDN),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.net_access_mode,
+				&g_fd_dict_data.net_access_mode),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.access_restriction_data,
+				&g_fd_dict_data.access_restriction_data),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.AMBR,
+				&g_fd_dict_data.AMBR),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.max_req_bandwidth_UL,
+				&g_fd_dict_data.max_req_bandwidth_UL),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.max_req_bandwidth_DL,
+				&g_fd_dict_data.max_req_bandwidth_DL),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.APN_config_profile,
+				&g_fd_dict_data.APN_config_profile),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.ctx_id,
+				&g_fd_dict_data.ctx_id),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.additional_ctx_id,
+				&g_fd_dict_data.additional_ctx_id),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.all_APN_configs_included_ind,
+				&g_fd_dict_data.all_APN_configs_included_ind),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.APN_config,
+				&g_fd_dict_data.APN_config),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.PDN_type,
+				&g_fd_dict_data.PDN_type),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.PDN_GW_alloc_type,
+				&g_fd_dict_data.PDN_GW_alloc_type),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.specific_APN_info,
+				&g_fd_dict_data.specific_APN_info),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.non_IP_PDN_type_ind,
+				&g_fd_dict_data.non_IP_PDN_type_ind),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.non_IP_data_delivery_mech,
+				&g_fd_dict_data.non_IP_data_delivery_mech),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.SCEF_ID,
+				&g_fd_dict_data.SCEF_ID),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.priority_Level,
+				&g_fd_dict_data.priority_Level),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.location_area_id,
+				&g_fd_dict_data.location_area_id),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.tracking_area_id,
+				&g_fd_dict_data.tracking_area_id),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.subsc_periodic_RAU_TAU_tmr,
+				&g_fd_dict_data.subsc_periodic_RAU_TAU_tmr),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.PUR_flags,
+				&g_fd_dict_data.PUR_flags),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.reg_subs_zone_code,
+				&g_fd_dict_data.reg_subs_zone_code),
+				return S6A_FD_ERROR);
+
+	CHECK_FCT_DO(fd_dict_getval(g_fd_dict_objs.cancellation_type,
+				&g_fd_dict_data.cancellation_type),
+				return S6A_FD_ERROR);
+	return SUCCESS;
+}
+
+int
+s6a_fd_cb_reg(void)
+{
+	log_msg(LOG_INFO, "ANJANA s6a_fd_cb_reg.\n");
+
+	struct disp_when data;
+
+	memset(&data, 0, sizeof(data));
+	data.app = g_fd_dict_objs.s6a_app;
+
+	/* Register resp callbacks */
+	data.command = g_fd_dict_objs.AIA;
+	CHECK_FCT_DO(fd_disp_register(aia_resp_callback, DISP_HOW_CC, &data,
+			NULL, NULL),
+			return S6A_FD_ERROR);
+
+	data.command = g_fd_dict_objs.ULA;
+	CHECK_FCT_DO(fd_disp_register(ula_resp_callback, DISP_HOW_CC, &data,
+			NULL, NULL),
+			return S6A_FD_ERROR);
+
+#if 0	
+	data.command = g_fd_dict_objs.PUA;
+	CHECK_FCT_DO(fd_disp_register(purge_resp_callback, DISP_HOW_CC, &data,
+	                     NULL, NULL),
+	                     return S6A_FD_ERROR);
+#endif
+	//NI Detach
+	data.command = g_fd_dict_objs.CLR;
+        CHECK_FCT_DO(fd_disp_register(clr_resp_callback, DISP_HOW_CC, &data,
+                        NULL, NULL),
+                        return S6A_FD_ERROR);
+	
+	//NI Detach
+	
+	CHECK_FCT_DO(fd_disp_app_support(g_fd_dict_objs.s6a_app,
+			g_fd_dict_objs.vendor_id, 1, 0),
+			return S6A_FD_ERROR);
+
+	return SUCCESS;
+}
+
+/**
+ * @brief Create session ID for every HSS request. Append UE ID to session ID
+ * initialized
+ * @param [out] session ID created
+ * @param [in] UE index to append to session ID
+ * @return int - error code
+ */
+short
+create_fd_sess_id(struct s6a_sess_info *s6a_sess,
+	int ue_idx)
+{
+	struct session *sess = NULL;
+	unsigned char *sess_id;
+	size_t sess_id_len;
+	char idx[10] = {0};
+
+	/* clear the session id if exists */
+	if (s6a_sess->sess_id_len > 0) {
+		int exist = false;
+		CHECK_FCT_DO(fd_sess_fromsid((unsigned char*)s6a_sess->sess_id,
+			s6a_sess->sess_id_len, &sess, &exist),
+			return S6A_FD_ERROR);
+
+		if (exist == 0) {
+			CHECK_FCT_DO(fd_sess_destroy(&sess), return S6A_FD_ERROR);
+			sess = NULL;
+		}
+	}
+
+	sprintf(idx, "%d", ue_idx);
+	if (sess == NULL) {
+		CHECK_FCT_DO(fd_sess_new(&sess, fd_g_config->cnf_diamid,
+		fd_g_config->cnf_diamid_len, (unsigned char*)idx, strlen(idx)),
+		return S6A_FD_ERROR);
+	}
+	CHECK_FCT_DO(fd_sess_getsid(sess, &sess_id, &sess_id_len),
+			return S6A_FD_ERROR);
+
+	s6a_sess->sess_id_len = (unsigned char)sess_id_len;
+	memcpy(s6a_sess->sess_id, sess_id, s6a_sess->sess_id_len);
+	s6a_sess->sess_id[s6a_sess->sess_id_len] = '\0';
+
+	return SUCCESS;
+}
+
+/**
+ * @brief Parse AVP received in freediameter response
+ * initialized
+ * @param [in]avp - AVP value receivned
+ * @param [out] result value parserd out of avp
+ * @return int - error code
+ */
+short
+parse_fd_result(struct avp *avp, struct fd_result *res)
+{
+	struct avp_hdr *hdr;
+	struct avp *child_avp = NULL;
+
+	CHECK_FCT_DO(fd_msg_avp_hdr(avp, &hdr), return S6A_FD_ERROR);
+	if (hdr->avp_code != g_fd_dict_data.exp_res.avp_code)
+	   return S6A_FD_ERROR;
+
+	CHECK_FCT_DO(fd_msg_browse(avp, MSG_BRW_FIRST_CHILD, &child_avp, NULL),
+			return S6A_FD_ERROR);
+
+	while (child_avp) {
+	   fd_msg_avp_hdr (child_avp, &hdr);
+
+	   if (hdr->avp_code ==
+		g_fd_dict_data.exp_res_code.avp_code) {
+			res->result_code = hdr->avp_value->u32;
+			res->present = true;
+		} else if (hdr->avp_code == g_fd_dict_data.vendor_id.avp_code) {
+			res->vendor_id = hdr->avp_value->u32;
+		}
+
+		CHECK_FCT_DO(fd_msg_browse(child_avp, MSG_BRW_NEXT, &child_avp,
+				NULL),
+				return S6A_FD_ERROR);
+	}
+
+	return SUCCESS;
+}
+
+
+
+
diff --git a/src/s6a/handlers/aia_handler.c b/src/s6a/handlers/aia_handler.c
new file mode 100644
index 0000000..bb096dd
--- /dev/null
+++ b/src/s6a/handlers/aia_handler.c
@@ -0,0 +1,269 @@
+/*
+ * Copyright (c) 2003-2018, Great Software Laboratory Pvt. Ltd.
+ * Copyright (c) 2017 Intel Corporation
+ * Copyright (c) 2019, Infosys Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *		http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <string.h>
+#include <unistd.h>
+#include <freeDiameter/freeDiameter-host.h>
+#include <freeDiameter/libfdcore.h>
+#include <freeDiameter/libfdproto.h>
+
+#include "log.h"
+#include "err_codes.h"
+#include "message_queues.h"
+#include "ipc_api.h"
+#include "s6a_fd.h"
+#include "s6a.h"
+#include "msgType.h"
+//#include "stage1_s6a_msg.h"
+#include "hss_message.h"
+
+#define DIAMETER_SUCCESS 2001
+
+/** Global and externs**/
+extern struct fd_dict_objects g_fd_dict_objs;
+extern struct fd_dict_data g_fd_dict_data;
+
+extern int g_Q_mme_S6a_fd;
+/**global and externs end**/
+
+/**
+ * @brief Parse authentication information avp recvd in AIA. This contains
+ * important security information for the UE
+ * @param [in] avp_data - AVP value received
+ * @param [out] aia - Security info is filled in to aia msg Q
+ * @return int - error code
+ */
+static int
+get_aia_sec_vector(struct avp *avp_data, struct aia_Q_msg *aia)
+{
+	struct avp *sub_avp = NULL;
+	struct avp_hdr *element = NULL;
+
+	CHECK_FCT_DO(fd_msg_avp_hdr(avp_data, &element),
+			return S6A_FD_ERROR);
+
+	/*Authentication-Info*/
+	if ((NULL == element) ||
+			(element->avp_code != g_fd_dict_data.auth_info.avp_code))
+		return S6A_FD_ERROR;
+
+	/*Find first sub child of Authentication-Info*/
+	CHECK_FCT_DO(fd_msg_browse(avp_data, MSG_BRW_FIRST_CHILD, &sub_avp,
+			NULL),
+			return S6A_FD_ERROR);
+
+	/*Lookup for sub element "E-UTRAN-Vector" in loop*/
+	while (NULL != sub_avp) {
+
+		fd_msg_avp_hdr(sub_avp, &element);
+
+		if ((NULL != element) && (element->avp_code ==
+			g_fd_dict_data.E_UTRAN_vector.avp_code))
+			/*Found the entry*/
+			break;
+
+		/*Iterate sub entries*/
+		CHECK_FCT_DO(fd_msg_browse(sub_avp, MSG_BRW_NEXT, &sub_avp,
+			NULL),
+			return S6A_FD_ERROR);
+	}
+
+	/*Element "E-UTRAN-Vector" not found, then return*/
+	if (NULL == sub_avp) return S6A_FD_ERROR;
+
+	CHECK_FCT_DO(fd_msg_browse(sub_avp, MSG_BRW_FIRST_CHILD,
+			&sub_avp, NULL),
+			return S6A_FD_ERROR);
+
+	/*Iterate all sub elements of E-UTRAN-Vector and filter sec vector params*/
+	for (;
+		NULL != sub_avp; /*Till null*/
+//		CHECK_FCT_DO(fd_msg_browse(sub_avp, MSG_BRW_NEXT, &sub_avp, NULL),
+//			return S6A_FD_ERROR) /*Iterate elements*/
+		) {
+
+		fd_msg_avp_hdr(sub_avp, &element);
+
+		/*AVP: RAND(1447) l=28 f=VM- vnd=TGPP*/
+		if (element->avp_code == g_fd_dict_data.RAND.avp_code) {
+
+			//if (element->avp_value->os.len > sizeof(aia->sec.rand.val))
+			if (element->avp_value->os.len > AIA_RAND_SIZE)
+				return S6A_FD_ERROR;
+
+			aia->sec.rand.len = element->avp_value->os.len;
+			memcpy(aia->sec.rand.val, element->avp_value->os.data,
+				aia->sec.rand.len);
+		}
+
+		/*AVP: XRES(1448) l=20 f=VM- vnd=TGPP*/
+		if (element->avp_code == g_fd_dict_data.XRES.avp_code) {
+
+			if (element->avp_value->os.len > AIA_RES_SIZE)
+				return S6A_FD_ERROR;
+
+			aia->sec.xres.len = element->avp_value->os.len;
+			memcpy(aia->sec.xres.val, element->avp_value->os.data,
+				aia->sec.xres.len);
+		}
+
+		/*AVP: AUTN(1449) l=28 f=VM- vnd=TGPP*/
+		if (element->avp_code == g_fd_dict_data.AUTN.avp_code) {
+
+			if (element->avp_value->os.len > AIA_AUTN_SIZE)
+				return S6A_FD_ERROR;
+
+			aia->sec.autn.len = element->avp_value->os.len;
+			memcpy(aia->sec.autn.val, element->avp_value->os.data,
+				aia->sec.autn.len);
+		}
+
+		/*AVP: KASME(1450) l=44 f=VM- vnd=TGPP*/
+		if (element->avp_code == g_fd_dict_data.KASME.avp_code) {
+
+			if (element->avp_value->os.len > AIA_KASME_SIZE)
+				return S6A_FD_ERROR;
+
+			aia->sec.kasme.len = element->avp_value->os.len;
+			memcpy(aia->sec.kasme.val, element->avp_value->os.data,
+				aia->sec.kasme.len);
+		}
+
+		CHECK_FCT_DO(fd_msg_browse(sub_avp, MSG_BRW_NEXT, &sub_avp, NULL),
+			return S6A_FD_ERROR) /*Iterate elements*/
+
+	}
+
+	return SUCCESS;
+}
+
+static
+void send_to_stage2(struct s6_incoming_msg_data_t *incoming_msg_p)
+{
+	TRACE_ENTRY("\n****************WRITE TO g_Q_mme_S6a_fd");
+
+	incoming_msg_p->destInstAddr = htonl(mmeAppInstanceNum_c);
+	incoming_msg_p->srcInstAddr = htonl(s6AppInstanceNum_c);
+
+	/*Send to stage2 queue*/
+	send_tipc_message(g_Q_mme_S6a_fd, mmeAppInstanceNum_c, (char*)incoming_msg_p, S6_READ_MSG_BUF_SIZE);
+}
+
+int aia_resp_callback(struct msg **buf, struct avp *_avp,
+		struct session *session, void *data,
+		enum disp_action * action)
+{
+	TRACE_ENTRY("\n****************ANJANA ******  Callback ----- >AIA recvd\n");
+	int res = SUCCESS, sess_id_len;
+	struct msg *resp = *buf;
+	struct avp *avp_ptr = NULL;
+	unsigned char *sess_id= NULL;
+	struct s6_incoming_msg_data_t s6_incoming_msgs;
+	struct avp_hdr *avp_hdr = NULL;
+
+	log_msg(LOG_INFO, "\nCallback ----- >AIA recvd\n");
+
+	dump_fd_msg(resp);
+	//TODO - workaround for dump call. Remove this.
+	{
+		char * buf = NULL;
+		size_t len = 0;
+		printf("*********AIA CALLBACK******%s\n", fd_msg_dump_treeview(&buf, &len, NULL, resp,
+					fd_g_config->cnf_dict, 0, 1));
+		free(buf);
+	}
+
+	CHECK_FCT_DO(fd_sess_getsid(session, &sess_id, (size_t*)&sess_id_len),
+		return S6A_FD_ERROR);
+
+	log_msg(LOG_INFO, "\nCallback ----- >session id=%s \n",sess_id);
+    
+	s6_incoming_msgs.msg_type = auth_info_answer;
+	/*Retrieve UE index embedded in to session ID string at AIR time*/
+	s6_incoming_msgs.ue_idx = get_ue_idx_from_fd_resp(sess_id, sess_id_len);
+
+	/*AVP: Result-Code(268)*/
+	fd_msg_search_avp(resp, g_fd_dict_objs.res_code, &avp_ptr);
+
+	if (NULL != avp_ptr) {
+		fd_msg_avp_hdr(avp_ptr, &avp_hdr);
+		res = avp_hdr->avp_value->u32;
+
+		if (DIAMETER_SUCCESS != res) {
+			log_msg(LOG_ERROR, "Diameter error with HSS\n");
+		}
+		//Vikram: chk res = SUCCESS;
+
+	} else {
+		struct fd_result fd_res;
+
+		avp_ptr = NULL;
+		fd_msg_search_avp(resp, g_fd_dict_objs.exp_res,
+			&avp_ptr);
+
+		if (NULL == avp_ptr) {
+			res = S6A_FD_ERROR;
+		} else if (parse_fd_result(avp_ptr, &fd_res) != 0) {
+			res = S6A_FD_ERROR;
+		} else res = fd_res.result_code;
+	}
+
+	if (DIAMETER_SUCCESS == res) {
+		/*AVP: Authentication-Info*/
+		fd_msg_search_avp(resp, g_fd_dict_objs.auth_info,
+			&avp_ptr);
+
+		if (NULL != avp_ptr) {
+			if (get_aia_sec_vector(avp_ptr, &s6_incoming_msgs.msg_data.aia_Q_msg_m) != SUCCESS)
+				res = S6A_FD_ERROR;
+		} else {
+			res = S6A_FD_ERROR;
+		}
+	}
+
+	/*Handled fd msg, do cleanup*/
+	fd_msg_free(*buf);
+
+	*buf = NULL;
+
+	if (DIAMETER_SUCCESS != res) s6_incoming_msgs.msg_data.aia_Q_msg_m.res = S6A_AIA_FAILED;
+
+	send_to_stage2(&s6_incoming_msgs);
+
+	return SUCCESS;
+}
+
+void
+handle_perf_hss_aia(int ue_idx, struct hss_aia_msg *aia)
+{
+    struct s6_incoming_msg_data_t msg;
+
+	msg.ue_idx = ue_idx;
+	msg.msg_type = auth_info_answer;
+	msg.msg_data.aia_Q_msg_m.res= 0;
+	memcpy(&(msg.msg_data.aia_Q_msg_m.sec.rand), &(aia->rand), sizeof(RAND));
+	memcpy(&(msg.msg_data.aia_Q_msg_m.sec.xres), &(aia->xres), sizeof(XRES));
+	memcpy(&(msg.msg_data.aia_Q_msg_m.sec.autn), &(aia->autn), sizeof(AUTN));
+	memcpy(&(msg.msg_data.aia_Q_msg_m.sec.kasme), &(aia->kasme), sizeof(KASME));
+
+	send_to_stage2(&msg);/*handle diameter error*/
+}
diff --git a/src/s6a/handlers/clr_handler.c b/src/s6a/handlers/clr_handler.c
new file mode 100644
index 0000000..b370375
--- /dev/null
+++ b/src/s6a/handlers/clr_handler.c
@@ -0,0 +1,147 @@
+/*
+ * Copyright (c) 2019, Infosys Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <string.h>
+#include <unistd.h>
+#include <freeDiameter/freeDiameter-host.h>
+#include <freeDiameter/libfdcore.h>
+#include <freeDiameter/libfdproto.h>
+
+#include "log.h"
+#include "err_codes.h"
+#include "message_queues.h"
+#include "ipc_api.h"
+#include "s6a_fd.h"
+#include "s6a.h"
+#include "msgType.h"
+//#include "detach_stage2_info.h"
+#include "hss_message.h"
+
+#define DIAMETER_SUCCESS 2001
+
+/** Global and externs**/
+extern struct fd_dict_objects g_fd_dict_objs;
+extern struct fd_dict_data g_fd_dict_data;
+extern int g_Q_mme_S6a_fd;
+/**global and externs end**/
+
+
+
+/**
+ * @brief callback handler for clr recvd from hss
+ * Parse clr, state and do cleanup for freediameter
+ * @params callback std
+ * @return error/success
+ */
+int
+clr_resp_callback(struct msg **buf, struct avp *avps, struct session *sess,
+			void *data, enum disp_action *action)
+{
+	struct msg *resp = NULL;
+	struct avp *avp_ptr = NULL;
+	struct s6_incoming_msg_data_t s6_incoming_msgs;
+	struct avp_hdr *avp_header = NULL;
+	unsigned int sess_id_len;
+	unsigned char *sess_id= NULL;
+
+	resp = *buf;
+
+	dump_fd_msg(resp);
+
+	/*read session id and extract ue index*/
+	CHECK_FCT_DO(fd_sess_getsid(sess, &sess_id, (size_t*)&sess_id_len),
+			return S6A_FD_ERROR);
+	log_msg(LOG_INFO, "\n CLR callback ----- >session id=%s \n",sess_id);
+    
+
+	/*AVP: Cancellation-Type*/
+	avp_ptr = NULL;
+	fd_msg_search_avp(resp, g_fd_dict_objs.cancellation_type, &avp_ptr);
+	if(NULL != avp_ptr) {
+		fd_msg_avp_hdr(avp_ptr, &avp_header);
+		s6_incoming_msgs.msg_data.clr_Q_msg_m.c_type = avp_header->avp_value->i32;
+	}
+	
+	fd_msg_search_avp(resp,g_fd_dict_objs.org_host, &avp_ptr);
+	if(NULL != avp_ptr) {
+		fd_msg_avp_hdr(avp_ptr, &avp_header);
+		memcpy(s6_incoming_msgs.msg_data.clr_Q_msg_m.origin_host,avp_header->avp_value->os.data,sizeof(s6_incoming_msgs.msg_data.clr_Q_msg_m.origin_host));
+		}
+
+	fd_msg_search_avp(resp, g_fd_dict_objs.org_realm, &avp_ptr);
+	if(NULL != avp_ptr) {
+		fd_msg_avp_hdr(avp_ptr, &avp_header);
+		memcpy(s6_incoming_msgs.msg_data.clr_Q_msg_m.origin_realm,avp_header->avp_value->os.data,sizeof(s6_incoming_msgs.msg_data.clr_Q_msg_m.origin_realm));
+		}
+         
+	fd_msg_search_avp(resp, g_fd_dict_objs.user_name,&avp_ptr);
+	if(NULL != avp_ptr) {
+		fd_msg_avp_hdr(avp_ptr, &avp_header);
+		memcpy(s6_incoming_msgs.msg_data.clr_Q_msg_m.imsi,avp_header->avp_value->os.data,sizeof(s6_incoming_msgs.msg_data.clr_Q_msg_m.imsi));
+		}
+       
+       /*CLA Processing*/
+
+       struct msg *ans, *qry;
+       struct avp * a;
+
+       if (buf == NULL)
+               return EINVAL;
+
+
+       /* Create answer header */
+       qry = *buf;
+       CHECK_FCT( fd_msg_new_answer_from_req ( fd_g_config->cnf_dict, buf, 0 ) );
+       ans = *buf;
+
+       /* Set the Origin-Host, Origin-Realm, Result-Code AVPs */
+       CHECK_FCT( fd_msg_rescode_set( ans, "DIAMETER_SUCCESS", NULL, NULL, 1 ) );
+
+       /* Send the answer */
+       CHECK_FCT( fd_msg_send( buf, NULL, NULL ) );
+
+	/*Do cleanup for freediameter*/
+	fd_msg_free(*buf);
+
+	*buf = NULL;
+	
+	s6_incoming_msgs.msg_type = cancel_location_request;
+
+	s6_incoming_msgs.destInstAddr = htonl(mmeAppInstanceNum_c);
+	s6_incoming_msgs.srcInstAddr = htonl(s6AppInstanceNum_c);
+
+	/*Send to stage2 queue*/
+        send_tipc_message(g_Q_mme_S6a_fd, mmeAppInstanceNum_c, (char*)&s6_incoming_msgs, S6_READ_MSG_BUF_SIZE);
+	
+	return SUCCESS;
+}
+
+/*Handler for CLR coming from built in perf HS*/
+void
+handle_perf_hss_clr(int ue_idx, struct hss_clr_msg *clr)
+{
+	struct s6_incoming_msg_data_t msg;
+    
+	msg.msg_type = cancel_location_request;
+	msg.ue_idx = ue_idx;
+	memcpy(&(msg.msg_data.clr_Q_msg_m.c_type), &(clr->cancellation_type), sizeof(clr->cancellation_type));
+	/*Send to stage2 queue*/
+	write_ipc_channel(g_Q_mme_S6a_fd, (char*)&msg, S6_READ_MSG_BUF_SIZE);
+}
diff --git a/src/s6a/handlers/detach_session_handler.c b/src/s6a/handlers/detach_session_handler.c
new file mode 100644
index 0000000..62f26f8
--- /dev/null
+++ b/src/s6a/handlers/detach_session_handler.c
@@ -0,0 +1,235 @@
+/*
+ * Copyright (c) 2003-2018, Great Software Laboratory Pvt. Ltd.
+ * Copyright (c) 2017 Intel Corporation
+ * Copyright (c) 2019, Infosys Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *		http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <freeDiameter/freeDiameter-host.h>
+#include <freeDiameter/libfdcore.h>
+#include <freeDiameter/libfdproto.h>
+
+#include "err_codes.h"
+#include "message_queues.h"
+#include "ipc_api.h"
+#include "sec.h"
+#include "s6a_fd.h"
+#include "s6a.h"
+#include "s6a_config.h"
+#include "msgType.h"
+//#include "detach_stage1_info.h"
+
+/************************************************************************
+Current file : Stage  - AIR handler of S6A
+ATTACH stages :
+@@@	Stage 1 : IAM-->[stage1 handler]-->AIR, ULR
+	Stage 2 : AIA, ULA -->[stage2 handler]--> Auth req
+	Stage 3 : Auth resp-->[stage1 handler]-->Sec mode cmd
+	Stage 4 : sec mode resp-->[stage1 handler]-->esm infor req
+	Stage 5 : esm infor resp-->[stage1 handler]-->create session
+	Stage 6 : create session resp-->[stage1 handler]-->init ctx setup
+	Stage 7 : attach complete-->[stage1 handler]-->modify bearer
+**************************************************************************/
+
+/****Globals and externs ***/
+
+static int g_Q_detachread_fd;
+
+/*Making global just to avoid stack passing*/
+
+static char buf[S6A_PURGEREQ_STAGE1_BUF_SIZE];
+
+extern s6a_config g_s6a_cfg;
+extern struct fd_dict_objects g_fd_dict_objs;
+extern struct fd_dict_data g_fd_dict_data;
+/****Global and externs end***/
+
+/**
+Initialize the stage settings, Q,
+destination communication etc.
+*/
+static void
+init_stage()
+{
+	log_msg(LOG_INFO, "Waiting for session detach initialiser  from mme-app\n");
+	if ((g_Q_detachread_fd  = open_ipc_channel(S6A_DTCHREQ_STAGE1_QUEUE, IPC_READ)) == -1){
+		log_msg(LOG_ERROR, "Error in opening reader detach channel.\n");
+		pthread_exit(NULL);
+	}
+	return;
+}
+
+/**
+* Read next message from stage Q for processing.
+*/
+static int
+read_next_msg()
+{
+	int bytes_read=0;
+	memset(buf, 0, S6A_PURGEREQ_STAGE1_BUF_SIZE);
+	while (bytes_read < S6A_PURGEREQ_STAGE1_BUF_SIZE) {//TODO : Recheck condition
+		if ((bytes_read = read_ipc_channel(
+			g_Q_detachread_fd, buf, S6A_PURGEREQ_STAGE1_BUF_SIZE)) == -1) {
+			log_msg(LOG_ERROR, "Error in reading from AIR Q.\n");
+			/* TODO : Add proper error handling */
+		}
+		log_msg(LOG_INFO, "Purge msg received, len - %d\n", bytes_read);
+	}
+	return bytes_read;
+}
+
+/**
+ * @brief Prepare PUR freediameter message, dump and post to HSS
+ * @param[in] ue_idx UE indx to append to session id
+ * @param[in] imsi - IMSI
+ * @return int Sucess or failure code
+ */
+static int
+send_purge(int ue_idx, char imsi[])
+{
+	struct msg *fd_msg = NULL;
+	union avp_value val;
+	struct s6a_sess_info s6a_sess = {.sess_id="", .sess_id_len = 0};
+
+	if(SUCCESS != create_fd_sess_id(&s6a_sess, ue_idx)) return S6A_FD_ERROR;
+
+	CHECK_FCT_DO(fd_msg_new(g_fd_dict_objs.PUR, MSGFL_ALLOC_ETEID, &fd_msg),
+			return S6A_FD_ERROR);
+
+	/*AVP: Session-Id*/
+	val.os.data = (unsigned char*)s6a_sess.sess_id;
+	val.os.len = strlen(s6a_sess.sess_id);
+	add_fd_msg(&val, g_fd_dict_objs.sess_id, &fd_msg);
+
+	/*AVP: Auth-Session-State*/
+	val.i32 = 1; /*NO_STATE_MAINTAINED*/
+	val.os.len = 0;
+	add_fd_msg(&val, g_fd_dict_objs.auth_sess_state, &fd_msg);
+
+	/*AVP: Origin-Host/Realm*/
+	CHECK_FCT_DO(fd_msg_add_origin(fd_msg, 0), return S6A_FD_ERROR);
+
+	/*AVP: Destination-Host*/
+	val.os.data = (unsigned char *)g_s6a_cfg.hss_host_name;
+	val.os.len = strlen(g_s6a_cfg.hss_host_name);
+	add_fd_msg(&val, g_fd_dict_objs.dest_host, &fd_msg);
+
+	/*AVP: Destination-Realm*/
+	val.os.data = (unsigned char*)g_s6a_cfg.realm;
+	val.os.len = strlen(g_s6a_cfg.realm);
+	add_fd_msg(&val, g_fd_dict_objs.dest_realm, &fd_msg);
+
+	/*AVP: User-Name*/
+	val.os.data = (unsigned char*)imsi;
+	val.os.len = strlen(imsi);
+	add_fd_msg(&val, g_fd_dict_objs.user_name, &fd_msg);
+
+	/*AVP: PUR-Flags*/
+	val.u32 = true;
+	val.os.len = 0;
+	add_fd_msg(&val, g_fd_dict_objs.PUR_flags, &fd_msg);
+
+	dump_fd_msg(fd_msg);
+
+	/*Post message to hss*/
+	CHECK_FCT_DO(fd_msg_send(&fd_msg, NULL, NULL), return S6A_FD_ERROR);
+
+	return SUCCESS;
+}
+
+static void
+send_rpc_purge(int ue_idx, char imsi[])
+{
+	/* TODO: For builitn HSS, we are not sending purge request to HSS,
+	 * returning dummy reply. Send request to builtin HSS and
+	 * handle response.
+	 */
+	handle_perf_hss_purge_resp(ue_idx);
+	return;
+}
+
+/**
+* Stage specific message processing.
+*/
+static int
+detach_processing()
+{
+	struct s6a_purge_Q_msg *purge_msg = (struct s6a_purge_Q_msg*)buf;
+	char imsi[16] = {0};
+
+	/*Parse and validate  the buffer*/
+	imsi_bin_to_str(purge_msg->IMSI, imsi);
+	log_msg(LOG_INFO, "IMSI recvd - %s\n", imsi);
+
+	if (HSS_FD == g_s6a_cfg.hss_type)
+		send_purge(purge_msg->ue_idx, imsi);
+	else {
+		log_msg(LOG_INFO, "Sending over IPC \n");
+		send_rpc_purge(purge_msg->ue_idx, imsi);
+	}
+
+	return SUCCESS;
+}
+
+/**
+* Post message to next handler of the stage
+*/
+static int
+post_to_next()
+{
+	return SUCCESS;
+}
+
+/**
+* Thread exit function for future reference.
+*/
+void
+shutdown_detach()
+{
+	close_ipc_channel(g_Q_detachread_fd);
+	log_msg(LOG_INFO, "Shutdown detach handler \n");
+	pthread_exit(NULL);
+	return;
+}
+
+
+/**
+* Thread function for stage.
+*/
+void*
+detach_handler(void *data)
+{
+	init_stage();
+
+	sleep(5);
+
+	log_msg(LOG_INFO, "Detach Q handler ready.\n");
+
+	while(1){
+		read_next_msg();
+
+		detach_processing();
+
+		post_to_next();
+	}
+
+	return NULL;
+}
+
diff --git a/src/s6a/handlers/hss_message_delegator.c b/src/s6a/handlers/hss_message_delegator.c
new file mode 100644
index 0000000..ab7d9a0
--- /dev/null
+++ b/src/s6a/handlers/hss_message_delegator.c
@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2003-2018, Great Software Laboratory Pvt. Ltd.
+ * Copyright (c) 2017 Intel Corporation
+ * Copyright (c) 2019, Infosys Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <string.h>
+#include <pthread.h>
+
+#include "log.h"
+#include "hss_message.h"
+#include "s6a.h"
+
+/**Global and externs **/
+
+/*Handle all messages coming from in built perf hss*/
+void
+hss_resp_handler(void *message)
+{
+	struct hss_resp_msg *msg = (struct hss_resp_msg*)message;
+
+	log_msg(LOG_INFO, "HSS response msg handler for ue_idx %d\n",
+			msg->ue_idx);
+
+	switch(msg->hdr){
+	case HSS_AIA_MSG:
+		handle_perf_hss_aia(msg->ue_idx,
+				(struct hss_aia_msg *)&(msg->data.aia));
+		break;
+
+	case HSS_ULA_MSG:
+		handle_perf_hss_ula(msg->ue_idx,
+				(struct hss_ula_msg *)&(msg->data.ula));
+		break;
+#if 0
+	case HSS_PURGE_RESP_MSG:
+		handle_perf_hss_purge_resp(msg->ue_idx);
+		break;
+#endif
+	//NI Detach
+	case HSS_CLR_MSG:
+		log_msg(LOG_INFO,"clr msg from TC\n");
+		handle_perf_hss_clr(msg->ue_idx,
+				(struct hss_clr_msg *)&(msg->data.clr));
+		break;
+
+	default:
+		log_msg(LOG_ERROR, "Unknown message received from HSS - %d\n",
+			msg->hdr);
+	}
+	return;
+
+	/*free allocated message buffer*/
+	free(message);
+}
diff --git a/src/s6a/handlers/purge_handler.c b/src/s6a/handlers/purge_handler.c
new file mode 100644
index 0000000..0ffe8e2
--- /dev/null
+++ b/src/s6a/handlers/purge_handler.c
@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2003-2018, Great Software Laboratory Pvt. Ltd.
+ * Copyright (c) 2017 Intel Corporation
+ * Copyright (c) 2019, Infosys Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <string.h>
+#include <unistd.h>
+#include <freeDiameter/freeDiameter-host.h>
+#include <freeDiameter/libfdcore.h>
+#include <freeDiameter/libfdproto.h>
+
+#include "log.h"
+#include "err_codes.h"
+#include "message_queues.h"
+#include "ipc_api.h"
+#include "s6a_fd.h"
+#include "s6a.h"
+#include "msgType.h"
+//#include "detach_stage2_info.h"
+#include "hss_message.h"
+
+/** Global and externs**/
+extern struct fd_dict_objects g_fd_dict_objs;
+extern struct fd_dict_data g_fd_dict_data;
+extern int g_Q_mme_S6a_fd;
+/**global and externs end**/
+
+static
+void send_to_stage2(struct s6_incoming_msg_data_t *incoming_msg_p)
+{
+	/*Send to stage2 queue*/
+	write_ipc_channel(g_Q_mme_S6a_fd, (char*)incoming_msg_p,
+			S6_READ_MSG_BUF_SIZE);
+}
+
+/**
+ * @brief callback handler for purge answer recvd from hss
+ * Parse purge answer, state and do cleanup for freediameter
+ * @params callback std
+ * @return error/success
+ */
+int
+purge_resp_callback(struct msg **buf, struct avp *avps, struct session *sess,
+			void *data, enum disp_action *action)
+{
+	struct msg *resp = NULL;
+	struct avp *avp_ptr = NULL;
+	struct s6_incoming_msg_data_t s6_incoming_msgs;
+	struct avp_hdr *avp_header = NULL;
+	unsigned int sess_id_len;
+	unsigned char *sess_id= NULL;
+
+	resp = *buf;
+
+	dump_fd_msg(resp);
+
+	/*read session id and extract ue index*/
+	CHECK_FCT_DO(fd_sess_getsid(sess, &sess_id, (size_t*)&sess_id_len),
+			return S6A_FD_ERROR);
+	log_msg(LOG_INFO, "\nPurge callback ----- >session id=%s \n",sess_id);
+    
+	s6_incoming_msgs.msg_type = purge_answser;
+	s6_incoming_msgs.ue_idx = get_ue_idx_from_fd_resp(sess_id, sess_id_len);
+
+	/*AVP: Result-Code*/
+	avp_ptr = NULL;
+	fd_msg_search_avp(resp, g_fd_dict_objs.res_code, &avp_ptr);
+
+	if(NULL != avp_ptr) {
+		fd_msg_avp_hdr(avp_ptr, &avp_header);
+		s6_incoming_msgs.msg_data.purge_resp_Q_msg_m.status = avp_header->avp_value->u32;
+
+		if (SUCCESS != s6_incoming_msgs.msg_data.purge_resp_Q_msg_m.status) {
+			s6_incoming_msgs.msg_data.purge_resp_Q_msg_m.status = S6A_FD_ERROR;
+		}
+	} else {
+		struct fd_result res;
+		avp_ptr = NULL;
+
+		fd_msg_search_avp(resp, g_fd_dict_objs.exp_res,
+			&avp_ptr);
+
+		if (NULL != avp_ptr) {
+			s6_incoming_msgs.msg_data.purge_resp_Q_msg_m.status = S6A_FD_ERROR;
+		}
+
+		if (parse_fd_result(avp_ptr, &res) != SUCCESS) {
+			s6_incoming_msgs.msg_data.purge_resp_Q_msg_m.status = S6A_FD_ERROR;
+		}
+		s6_incoming_msgs.msg_data.purge_resp_Q_msg_m.status =res.result_code;
+	}
+
+	/*Inform response to mme-app*/
+	send_to_stage2(&s6_incoming_msgs);
+
+	/*Do cleanup for freediameter*/
+	fd_msg_free(*buf);
+
+	*buf = NULL;
+
+	return SUCCESS;
+}
+
+/*Handler for AIA coming from built in perf HS*/
+void
+handle_perf_hss_purge_resp(int ue_idx)
+{
+	struct s6_incoming_msg_data_t resp;
+    
+	resp.msg_type = purge_answser;
+	resp.ue_idx = ue_idx;
+	resp.msg_data.purge_resp_Q_msg_m.status = 0;
+
+	send_to_stage2(&resp);
+}
diff --git a/src/s6a/handlers/s6a_req_handler.c b/src/s6a/handlers/s6a_req_handler.c
new file mode 100644
index 0000000..8bc361b
--- /dev/null
+++ b/src/s6a/handlers/s6a_req_handler.c
@@ -0,0 +1,346 @@
+/*
+ * Copyright (c) 2003-2018, Great Software Laboratory Pvt. Ltd.
+ * Copyright (c) 2017 Intel Corporation
+ * Copyright (c) 2019, Infosys Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *		http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <freeDiameter/freeDiameter-host.h>
+#include <freeDiameter/libfdcore.h>
+#include <freeDiameter/libfdproto.h>
+
+#include "s6a_config.h"
+#include "err_codes.h"
+#include "message_queues.h"
+#include "ipc_api.h"
+#include "sec.h"
+#include "msgType.h"
+//#include "stage1_s6a_msg.h"
+#include "s6a_fd.h"
+#include "s6a.h"
+#include "s6a_config.h"
+#include "hss_message.h"
+
+/************************************************************************
+Current file : Stage  - AIR handler of S6A
+ATTACH stages :
+@@@	Stage 1 : IAM-->[stage1 handler]-->AIR, ULR
+	Stage 2 : AIA, ULA -->[stage2 handler]--> Auth req
+	Stage 3 : Auth resp-->[stage1 handler]-->Sec mode cmd
+	Stage 4 : sec mode resp-->[stage1 handler]-->esm infor req
+	Stage 5 : esm infor resp-->[stage1 handler]-->create session
+	Stage 6 : create session resp-->[stage1 handler]-->init ctx setup
+	Stage 7 : attach complete-->[stage1 handler]-->modify bearer
+**************************************************************************/
+
+/****Globals and externs ***/
+extern int g_our_hss_fd;
+extern s6a_config  g_s6a_cfg;
+extern struct fd_dict_objects g_fd_dict_objs;
+extern struct fd_dict_data g_fd_dict_data;
+/****Global and externs end***/
+
+
+void ulr_intermediate_cb(void * data, struct msg ** msg)
+{
+	dump_fd_msg(*msg);
+}
+
+/**
+ * @brief Prepare ULR freediameter message, dump and post to HSS
+ * @param[in] aia_msg - AIA info recvd from mme-app
+ * @param[in] imsi - IMSI
+ * @return int Sucess or failure code
+ */
+static int
+send_FD_ULR(struct s6a_Q_msg *aia_msg, char imsi[])
+{
+	struct msg *fd_msg = NULL;
+	int res = SUCCESS;
+	struct s6a_sess_info s6a_sess = {.sess_id="", .sess_id_len = 0};
+	char event = 12;
+	union avp_value val;
+
+	/*Create FD header and message for update location request.*/
+	if(SUCCESS != (res = create_fd_sess_id(&s6a_sess, aia_msg->ue_idx)))
+		return res;
+
+	CHECK_FCT_DO(fd_msg_new(g_fd_dict_objs.ULR, MSGFL_ALLOC_ETEID, &fd_msg),
+			return S6A_FD_ERROR)
+
+	/*AVP: Session-Id*/
+	val.os.data = (unsigned char*)s6a_sess.sess_id;
+	val.os.len = strlen(s6a_sess.sess_id);
+	add_fd_msg(&val, g_fd_dict_objs.sess_id, &fd_msg);
+
+	/*AVP: Auth-Session-State*/
+	val.i32 = 1; /*NO_STATE_MAINTAINED*/
+	val.os.len = 0;
+	add_fd_msg(&val, g_fd_dict_objs.auth_sess_state, &fd_msg);
+
+	/*AVP: Origin-Host/Realm*/
+	CHECK_FCT_DO(fd_msg_add_origin(fd_msg, 0), return S6A_FD_ERROR);
+
+	/*AVP: Destination-Host*/
+	val.os.data = (unsigned char*)g_s6a_cfg.hss_host_name;
+	val.os.len = strlen(g_s6a_cfg.hss_host_name);
+	add_fd_msg(&val, g_fd_dict_objs.dest_host, &fd_msg);
+
+	/*AVP: Destination-Realm*/
+	val.os.data = (unsigned char*)g_s6a_cfg.realm;
+	val.os.len = strlen(g_s6a_cfg.realm);
+	add_fd_msg(&val, g_fd_dict_objs.dest_realm, &fd_msg);
+
+	/*AVP: User-Name*/
+	val.os.data = (unsigned char*)imsi;
+	val.os.len = strlen(imsi);
+	add_fd_msg(&val, g_fd_dict_objs.user_name, &fd_msg);
+
+	/*AVP: RAT-Type*/
+	val.u32 = S6A_RAT_EUTRAN;
+	val.os.len = 0;
+	add_fd_msg(&val, g_fd_dict_objs.RAT_type, &fd_msg);
+
+	/*AVP: ULR-Flags*/
+	val.u32 = ULR_FLAG_S6AS6D_IND | ULR_FLAG_INIT_ATCH_IND ;
+	add_fd_msg(&val, g_fd_dict_objs.ULR_flags, &fd_msg);
+
+	/*AVP: Visited-PLMN-Id*/
+	val.os.data = (unsigned char*)aia_msg->tai.plmn_id.idx;
+	val.os.len = 3;
+	add_fd_msg(&val, g_fd_dict_objs.visited_PLMN_id, &fd_msg);
+
+	dump_fd_msg(fd_msg);
+
+	/*Post ULR to HSS*/
+	CHECK_FCT_DO(fd_msg_send(&fd_msg, ulr_intermediate_cb, (void*)&event),
+			return S6A_FD_ERROR);
+
+	return SUCCESS;
+}
+
+
+/**
+ * @brief dump recvd aia queue msg
+ * @param[in] air_msg - IMSI
+ * @return void
+ */
+void
+dump_s6a_msg(struct s6a_Q_msg *air_msg)
+{
+	log_msg(LOG_INFO, "Received index= %d\n",air_msg->ue_idx);
+	log_msg(LOG_INFO, "Received plmn %x %x %x= %d\n",air_msg->tai.plmn_id.idx[0],
+			air_msg->tai.plmn_id.idx[1], air_msg->tai.plmn_id.idx[2]);
+}
+
+/**
+ * @brief Prepare AIR freediameter message, dump and post to HSS
+ * @param[in] aia_msg - AIA info recvd from mme-app
+ * @param[in] imsi - IMSI
+ * @return int Sucess or failure code
+ */
+static int
+send_FD_AIR(struct s6a_Q_msg *aia_msg, char imsi[])
+{
+	struct avp *avp_ptr = NULL;
+	struct msg *fd_msg = NULL;
+	int res = 0;
+	struct s6a_sess_info s6a_sess = {.sess_id="", .sess_id_len = 0};
+	union avp_value val;
+
+	log_msg(LOG_INFO, "In Send AIR:\n");
+	dump_s6a_msg(aia_msg);
+
+	/*Create FD header and message for authentication info request.*/
+	if(SUCCESS != (res = create_fd_sess_id(&s6a_sess, aia_msg->ue_idx)))
+		return res;
+
+	CHECK_FCT_DO(fd_msg_new(g_fd_dict_objs.AIR, MSGFL_ALLOC_ETEID, &fd_msg),
+			return S6A_FD_ERROR);
+
+	/*AVP: Session-Id*/
+	val.os.data = (unsigned char*)s6a_sess.sess_id;
+	val.os.len = strlen(s6a_sess.sess_id);
+	add_fd_msg(&val, g_fd_dict_objs.sess_id, &fd_msg);
+
+	/*AVP: Auth-Session-State*/
+	val.i32 = 1; /*NO_STATE_MAINTAINED*/
+	val.os.len = 0;
+	add_fd_msg(&val, g_fd_dict_objs.auth_sess_state, &fd_msg);
+
+	/*AVP: Origin-Host/Realm*/
+	CHECK_FCT_DO(fd_msg_add_origin(fd_msg, 0), return S6A_FD_ERROR)
+
+	/*AVP: Destination-Host*/
+	val.os.data = (unsigned char*)g_s6a_cfg.hss_host_name;
+	val.os.len = strlen(g_s6a_cfg.hss_host_name);
+	add_fd_msg(&val, g_fd_dict_objs.dest_host, &fd_msg);
+
+	/*AVP: Destination-Realm*/
+	val.os.data = (unsigned char*)g_s6a_cfg.realm;
+	val.os.len = strlen(g_s6a_cfg.realm);
+	add_fd_msg(&val, g_fd_dict_objs.dest_realm, &fd_msg);
+
+	/*AVP: User-Name*/
+	val.os.data = (unsigned char*)imsi;
+	val.os.len = strlen(imsi);
+	add_fd_msg(&val, g_fd_dict_objs.user_name, &fd_msg);
+
+	/*AVP: Visited-PLMN-Id*/
+	val.os.data = (unsigned char*)aia_msg->tai.plmn_id.idx;
+	val.os.len = 3;
+	add_fd_msg(&val, g_fd_dict_objs.visited_PLMN_id, &fd_msg);
+
+	/*TODO: recheck. Can it be grouped better way*/
+	/*AVP: Requested-EUTRAN-Authentication-Info*/
+	CHECK_FCT_DO(fd_msg_avp_new(
+		g_fd_dict_objs.req_EUTRAN_auth_info, 0, &avp_ptr),
+		return -1);
+	CHECK_FCT_DO(fd_msg_avp_add(fd_msg, MSG_BRW_LAST_CHILD, avp_ptr), return -1);
+
+	/*AVP: Requested-EUTRAN-Authentication-Info
+	 *----->AVP: Number-Of-Requested-Vectors(1410)*/
+	val.i32 = 1;
+	val.os.len = 0;
+	add_fd_msg(&val, g_fd_dict_objs.no_of_req_vectors,
+			(struct msg**)&avp_ptr);
+
+	/*AVP: Requested-EUTRAN-Authentication-Info
+	 * ------>AVP: Immediate-Response-Preferred*/
+	val.u32 = 0;
+	add_fd_msg(&val, g_fd_dict_objs.immediate_resp_pref,
+			(struct msg**)&avp_ptr);
+
+	dump_fd_msg(fd_msg);
+
+	/*post AIR to hss */
+	CHECK_FCT_DO(fd_msg_send(&fd_msg, NULL, NULL), return S6A_FD_ERROR);
+
+	return SUCCESS;
+}
+
+/**
+API to send AIR oto customer HSS over custome RPC
+*/
+static void
+send_rpc_AIR(struct s6a_Q_msg *air_msg, char imsi[])
+{
+	struct hss_req_msg msg;
+
+	msg.hdr = HSS_AIR_MSG;
+	msg.ue_idx = air_msg->ue_idx;
+
+	strncpy(msg.data.air.imsi, imsi, IMSI_STR_LEN);
+	memcpy(msg.data.air.plmn_id, air_msg->tai.plmn_id.idx, 3);
+
+	if (write(g_our_hss_fd, &msg, HSS_REQ_MSG_SIZE) < 0) {
+		log_msg(LOG_ERROR, "HSS AIR msg send failed.\n");
+		 		perror("writing on stream socket");
+	}
+	log_msg(LOG_INFO, "AIR msg send to hss for ue_idx %d\n",
+		air_msg->ue_idx);
+}
+
+/**
+API to send ULR oto customer HSS over custome RPC
+*/
+static void
+send_rpc_ULR(struct s6a_Q_msg *ulr_msg, char imsi[])
+{
+	struct hss_req_msg msg;
+
+	msg.hdr = HSS_ULR_MSG;
+	msg.ue_idx = ulr_msg->ue_idx;
+
+	strncpy(msg.data.air.imsi, imsi, IMSI_STR_LEN);
+	memcpy(msg.data.air.plmn_id, ulr_msg->tai.plmn_id.idx, 3);
+
+	if (write(g_our_hss_fd, &msg, HSS_REQ_MSG_SIZE) < 0) {
+		log_msg(LOG_ERROR, "HSS ULR msg send failed.\n");
+		perror("writing on stream socket");
+	}
+	log_msg(LOG_INFO, "ULR msg send to hss\n");
+}
+
+
+/**
+ * @brief convert binary imsi to string imsi
+ * Binary imsi is stored in 8 bytes, each nibble representing each imsi char.
+ * char imsi stroes each char in 1 byte.
+ * @param[in] b_imsi : Binary imsi
+ * @param[out] s_imsi : Converted string imsi
+ * @return void
+ */
+void
+imsi_bin_to_str(unsigned char *b_imsi, char *s_imsi)
+{
+	if(NULL == b_imsi || NULL == s_imsi) return;
+
+	memset(s_imsi, 0, STR_IMSI_LEN);
+
+	/* Byte 'AB' in b_imsi, is converted to two bytes 'A', 'B' in s_imsi*/
+	s_imsi[0] = '0' + ((b_imsi[0]>>4) & 0x0F);
+
+	for(int i=1; i < BINARY_IMSI_LEN; ++i) {
+		s_imsi[(i*2)-1] = '0' + (b_imsi[i] & 0x0F);
+		s_imsi[(i*2)] = '0' + ((b_imsi[i]>>4) & 0x0F);
+	}
+	s_imsi[(BINARY_IMSI_LEN*2)-1] = '\0';
+}
+
+/**
+ * @brief Post AIR and ULR messsages simultaneously to HSS.
+ * @return int Sucess or failure code
+ */
+static int
+AIR_processing(struct s6a_Q_msg * air_msg)
+{
+	log_msg(LOG_INFO, "IMSI recvd - %s\n %d \n", air_msg->imsi, air_msg->msg_type);
+
+	if(HSS_FD == g_s6a_cfg.hss_type) {
+		if(air_msg->msg_type == auth_info_request)
+			/*post to next processing*/
+			send_FD_AIR(air_msg, air_msg->imsi);
+		else if(air_msg->msg_type == update_loc_request)
+			send_FD_ULR(air_msg, air_msg->imsi);
+
+	} else {
+		log_msg(LOG_INFO, "Sending over IPC\n");
+		send_rpc_AIR(air_msg, air_msg->imsi);
+		send_rpc_ULR(air_msg, air_msg->imsi);
+	}
+
+	return SUCCESS;
+}
+
+/*
+* Thread function for stage.
+*/
+void*
+S6Req_handler(void *data)
+{
+	log_msg(LOG_INFO, "AIR Q handler ready.\n");
+
+	char *msg = ((char *) data) + ((sizeof(uint32_t)) * 2);
+	
+	AIR_processing((struct s6a_Q_msg *)msg);
+	
+	return NULL;
+}
diff --git a/src/s6a/handlers/ula_handler.c b/src/s6a/handlers/ula_handler.c
new file mode 100644
index 0000000..e9a49b8
--- /dev/null
+++ b/src/s6a/handlers/ula_handler.c
@@ -0,0 +1,240 @@
+/*
+ * Copyright (c) 2003-2018, Great Software Laboratory Pvt. Ltd.
+ * Copyright (c) 2017 Intel Corporation
+ * Copyright (c) 2019, Infosys Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <ctype.h>
+#include <freeDiameter/freeDiameter-host.h>
+#include <freeDiameter/libfdproto.h>
+#include <freeDiameter/libfdcore.h>
+
+#include "log.h"
+#include "err_codes.h"
+#include "message_queues.h"
+#include "ipc_api.h"
+#include "s6a_fd.h"
+#include "s6a.h"
+#include "msgType.h"
+//#include "stage1_s6a_msg.h"
+#include "hss_message.h"
+
+extern int g_Q_mme_S6a_fd;
+extern struct fd_dict_objects g_fd_dict_objs;
+extern struct fd_dict_data g_fd_dict_data;
+
+/**
+ * @brief Parse subscription information for UE
+ * @param[in] avp_ptr - POinter to subscription data avp
+ * @param[out] ula information filled with parsed data
+ * @return void
+ */
+static void
+parse_ula_subscription_data(struct avp *avp_ptr, struct ula_Q_msg *ula)
+{
+	struct avp *next = NULL;
+	struct avp_hdr *element = NULL;
+
+    CHECK_FCT_DO(fd_msg_avp_hdr(avp_ptr, &element),
+                        return);
+
+    if ((NULL == element) ||
+           (element->avp_code != g_fd_dict_data.subscription_data.avp_code))
+        return;
+
+    CHECK_FCT_DO(fd_msg_browse(avp_ptr, MSG_BRW_FIRST_CHILD, &next, NULL),
+                    return);
+
+	for(;
+		NULL != next;
+		fd_msg_browse(next, MSG_BRW_NEXT, &next, NULL)) {
+
+		fd_msg_avp_hdr (next, &element);
+
+		if(NULL == element) return;
+
+		/*AVP: Access-Restriction-Data(1426)*/
+		if(g_fd_dict_data.access_restriction_data.avp_code ==
+				element->avp_code) {
+			ula->access_restriction_data = element->avp_value->u32;
+			continue;
+		}
+
+		/*AVP: Subscriber-Status(1424)*/
+		if(g_fd_dict_data.subscriber_status.avp_code == element->avp_code) {
+			ula->subscription_status = element->avp_value->i32;
+			continue;
+		}
+
+		/*AVP: Network-Access-Mode(1417)*/
+		if(g_fd_dict_data.net_access_mode.avp_code == element->avp_code) {
+			ula->net_access_mode = element->avp_value->i32;
+			continue;
+		}
+
+		/*AVP: Regional-Subscription-Zone-Code(1446)*/
+		if(g_fd_dict_data.reg_subs_zone_code.avp_code ==
+				element->avp_code) {
+			//element->avp_value : 10 string values of len 4
+			continue;
+		}
+
+		/*AVP: MSISDN(701)*/
+		if(g_fd_dict_data.MSISDN.avp_code == element->avp_code) {
+			memcpy(ula->MSISDN, element->avp_value->os.data, element->avp_value->os.len);
+			continue;
+		}
+
+		/*AVP: AMBR(1435)*/
+			/*AVP: Max-Requested-Bandwidth-UL(516)
+			  AVP: Max-Requested-Bandwidth-DL(515*/
+		if(g_fd_dict_data.AMBR.avp_code == element->avp_code) {
+			/*AMBR has its own child elements, iterate through those*/
+			struct avp *ambr_itr = NULL;
+			struct avp_hdr *ambr_element = NULL;
+
+			CHECK_FCT_DO(fd_msg_browse(next, MSG_BRW_FIRST_CHILD,
+						&ambr_itr, NULL), return);
+
+			/*Iterate through subscription data child avps*/
+			while(NULL != ambr_itr) {
+				fd_msg_avp_hdr(ambr_itr, &ambr_element);
+
+				if(g_fd_dict_data.max_req_bandwidth_UL.avp_code ==
+						ambr_element->avp_code) {
+					ula->max_requested_bw_ul = ambr_element->avp_value->u32;
+				}
+
+				if(g_fd_dict_data.max_req_bandwidth_DL.avp_code ==
+						ambr_element->avp_code) {
+					ula->max_requested_bw_dl = ambr_element->avp_value->u32;
+				}
+
+				CHECK_FCT_DO(fd_msg_browse(ambr_itr, MSG_BRW_NEXT,
+						&ambr_itr, NULL), return);
+			}
+			continue;
+		}
+
+		/*AVP: APN-Configuration-Profile(1429)*/
+			/*AVP: Context-Identifier(1423)
+			AVP: All-APN-Configurations-Included-Indicator(1428)
+			AVP: APN-Configuration(1430)*/
+		if(g_fd_dict_data.APN_config_profile.avp_code == element->avp_code) {
+			/*APN profile has its own child elements, iterate through
+			 * those*/
+			struct avp *apn_cfg_prof_itr = NULL;
+			struct avp_hdr *apn_cfg_element = NULL;
+
+			CHECK_FCT_DO(fd_msg_browse(next, MSG_BRW_FIRST_CHILD,
+						&apn_cfg_prof_itr, NULL), return);
+
+			/*Iterate through subscription data child avps*/
+			while(NULL != apn_cfg_prof_itr) {
+				fd_msg_avp_hdr(apn_cfg_prof_itr, &apn_cfg_element);
+
+				if(g_fd_dict_data.ctx_id.avp_code ==
+						apn_cfg_element->avp_code) {
+					ula->apn_config_profile_ctx_id =
+						apn_cfg_element->avp_value->u32;
+				} else
+				if(g_fd_dict_data.all_APN_configs_included_ind.avp_code ==
+						apn_cfg_element->avp_code) {
+					ula->all_APN_cfg_included_ind =
+						apn_cfg_element->avp_value->i32;
+				} else
+				if(g_fd_dict_data.APN_config.avp_code ==
+						apn_cfg_element->avp_code){
+					//APN configuration list : There is list of elements to read
+					//TODO : Write function to read all elements
+
+				}
+
+				CHECK_FCT_DO(fd_msg_browse(apn_cfg_prof_itr, MSG_BRW_NEXT,
+						&apn_cfg_prof_itr, NULL), return);
+			}
+			continue;
+		}
+
+		/*AVP: Subscribed-Periodic-RAU-TAU-Timer(1619)*/
+		if(g_fd_dict_data.subsc_periodic_RAU_TAU_tmr.avp_code
+				== element->avp_code) {
+			ula->RAU_TAU_timer = element->avp_value->u32;
+			continue;
+		}
+
+	}
+}
+
+/**
+ * @brief Call back registered to handle ULA from hss
+ * @param callback requiremd arguments
+ * @return int error code as success or failure
+ */
+int
+ula_resp_callback(struct msg **buf, struct avp *avp_ptr, struct session *sess,
+			void *data, enum disp_action *action)
+{
+	int sess_id_len, ue_idx;
+	unsigned char *sess_id= NULL;
+	struct s6_incoming_msg_data_t s6_incoming_msgs;
+	struct avp *subsc_ptr = NULL;
+
+	CHECK_FCT_DO(fd_sess_getsid(sess, &sess_id, (size_t*)&sess_id_len),
+		return S6A_FD_ERROR);
+
+	log_msg(LOG_INFO, "\nCallback ----- >session id=%s \n", sess_id);
+
+	s6_incoming_msgs.msg_data.ula_Q_msg_m.res = SUCCESS;
+	ue_idx = get_ue_idx_from_fd_resp(sess_id, sess_id_len);
+
+	/*AVP: Subscription-Data(1400)*/
+	fd_msg_search_avp(*buf, g_fd_dict_objs.subscription_data, &subsc_ptr);
+
+	/*Parse fd message and extract ula information*/
+	if(NULL != subsc_ptr) parse_ula_subscription_data(subsc_ptr, &s6_incoming_msgs.msg_data.ula_Q_msg_m);
+
+	fd_msg_free(*buf);
+	*buf = NULL;
+    
+	s6_incoming_msgs.msg_type = update_loc_answer;
+	s6_incoming_msgs.ue_idx = ue_idx;
+
+	s6_incoming_msgs.destInstAddr = htonl(mmeAppInstanceNum_c);
+	s6_incoming_msgs.srcInstAddr = htonl(s6AppInstanceNum_c);
+
+	/*Send to stage2 queue*/
+	send_tipc_message(g_Q_mme_S6a_fd, mmeAppInstanceNum_c, (char*)&s6_incoming_msgs, S6_READ_MSG_BUF_SIZE);
+
+	return SUCCESS;
+}
+
+/*Handler for ULA coming from built in perf HS*/
+void
+handle_perf_hss_ula(int ue_idx, struct hss_ula_msg *ula)
+{
+	struct s6_incoming_msg_data_t msg;
+    
+	msg.msg_type = update_loc_answer;
+	msg.ue_idx = ue_idx;
+	msg.msg_data.ula_Q_msg_m.res = ula->subscription_state;
+	/*Send to stage2 queue*/
+	write_ipc_channel(g_Q_mme_S6a_fd, (char*)&msg, S6_READ_MSG_BUF_SIZE);
+}
diff --git a/src/s6a/json_config.c b/src/s6a/json_config.c
new file mode 100644
index 0000000..01804fa
--- /dev/null
+++ b/src/s6a/json_config.c
@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2003-2018, Great Software Laboratory Pvt. Ltd.
+ * Copyright (c) 2017 Intel Corporation
+ * Copyright (c) 2019, Infosys Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <string.h>
+
+#include "json_data.h"
+#include "s6a_config.h"
+#include "err_codes.h"
+
+/**Globals and externs**/
+s6a_config g_s6a_cfg;
+/**Globals and externs**/
+
+/**
+ * @brief Initialize json parser and file reading
+ * @param  Path to json file
+ * @return void
+ */
+void
+init_parser(char *path)
+{
+	load_json(path);
+}
+
+/**
+ * @brief Read s6a configuration parameters from input json
+ * @param  None
+ * @return int - Success or fail
+ */
+int
+parse_s6a_conf()
+{
+	/*Read s11 config information*/
+	char *tmp = get_string_scalar("s6a.hss_type");
+	if(NULL == tmp) return E_FAIL;
+	if(!strcmp(tmp, "freediameter")) g_s6a_cfg.hss_type = HSS_FD;
+	else g_s6a_cfg.hss_type = HSS_PERF;
+	free(tmp);
+
+	g_s6a_cfg.hss_host_name = get_string_scalar("s6a.host_name");
+	if( NULL == g_s6a_cfg.hss_host_name) return E_FAIL;
+
+	g_s6a_cfg.realm = get_string_scalar("s6a.realm");
+	if(NULL == g_s6a_cfg.realm) return E_FAIL;
+
+	return SUCCESS;
+}
diff --git a/src/s6a/main.c b/src/s6a/main.c
new file mode 100644
index 0000000..9d851e3
--- /dev/null
+++ b/src/s6a/main.c
@@ -0,0 +1,288 @@
+/*
+ * Copyright (c) 2003-2018, Great Software Laboratory Pvt. Ltd.
+ * Copyright (c) 2017 Intel Corporation
+ * Copyright (c) 2019, Infosys Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <stdio.h>
+
+#include <freeDiameter/freeDiameter-host.h>
+#include <freeDiameter/libfdcore.h>
+#include <freeDiameter/libfdproto.h>
+#include "s6a_config.h"
+#include "s6a.h"
+#include "s6a_fd.h"
+#include "err_codes.h"
+#include "message_queues.h"
+#include "ipc_api.h"
+#include "hss_message.h"
+#include "thread_pool.h"
+#include <sys/types.h>
+
+/**Globals and externs**/
+struct fd_dict_objects g_fd_dict_objs;
+struct fd_dict_data g_fd_dict_data;
+int g_Q_mme_S6a_fd;
+
+int g_our_hss_fd;
+struct thread_pool *g_tpool;
+extern s6a_config g_s6a_cfg;
+
+pthread_t g_AIR_handler_tid, g_ULR_handler_tid;
+pthread_t g_detach_handler_tid;
+pthread_t g_our_hss_tid;
+
+extern char processName[255];
+extern int pid;
+
+int ipc_reader_tipc_s6;
+
+extern void*
+S6Req_handler(void *data);
+
+/**Globals and externs**/
+
+/**
+ * @brief Initialize communication channel IPC or IPC to non freediameter HSS
+ * ready
+ * @param  None
+ * @return void
+ */
+void
+init_hss_rpc()
+{
+	struct sockaddr_un hss_serv;
+
+	g_our_hss_fd = socket(AF_UNIX, SOCK_STREAM, 0);
+	if (g_our_hss_fd < 0) {
+		log_msg(LOG_ERROR, "HSS socket creation failed.\n");
+		perror("Error opening HSS socket");
+		exit(-1);
+	}
+
+	hss_serv.sun_family = AF_UNIX;
+	strcpy(hss_serv.sun_path, g_s6a_cfg.hss_ipc_endpt);
+
+	if (connect(g_our_hss_fd, (struct sockaddr *)&hss_serv,
+	sizeof(struct sockaddr_un)) < 0) {
+		log_msg(LOG_ERROR, "HSS connect failed.\n");
+		perror("connecting HSS socket");
+		close(g_our_hss_fd);
+		exit(-1);
+	}
+	log_msg(LOG_INFO, "Connected to HSS\n");
+}
+
+/**
+ * @brief Initialize freediameter library, dictionary and data elements
+ * ready
+ * @param  None
+ * @return int SUCCESS or S6A_FD_ERROR
+ */
+static int
+init_fd()
+{
+	log_msg(LOG_INFO, "INIT FD .. .\n");
+
+	/* Initialize the core freeDiameter library */
+	CHECK_FCT_DO(fd_core_initialize(), return S6A_FD_ERROR);
+
+	/* Parse the configuration file */
+	CHECK_FCT_DO(fd_core_parseconf(S6A_FD_CONF), return S6A_FD_ERROR);
+
+	if(SUCCESS != s6a_fd_init()) exit(S6A_FD_ERROR);
+
+	if(SUCCESS != s6a_fd_objs_init()) exit(S6A_FD_ERROR);
+
+	if(SUCCESS != s6a_fd_data_init()) exit(S6A_FD_ERROR);
+
+	if(SUCCESS != s6a_fd_cb_reg()) exit(S6A_FD_ERROR);
+
+	CHECK_FCT_DO( fd_core_start(), return S6A_FD_ERROR);
+
+	return SUCCESS;
+}
+
+/**
+ * @brief Unused
+ * ready
+ * @param
+ * @return i
+ */
+static void
+check_args(int argc, char **argv)
+{
+	/*Parsse arguments to extract file path*/
+	/*If no file path mentioned then use default*/
+	/*For wrong arguments print help*/
+	return;
+}
+
+void * AIR_handler(void * data)
+{
+	int bytesRead = 0;
+	while (1)
+	{
+		unsigned char buffer[255] = {0};
+		if ((bytesRead = read_tipc_msg(ipc_reader_tipc_s6, buffer, 255)) > 0)
+		{
+			unsigned char *tmpBuf = (unsigned char *) malloc(sizeof(char) * bytesRead);
+			memcpy(tmpBuf, buffer, bytesRead);
+			log_msg(LOG_INFO, "S6 message received from mme-app");
+			S6Req_handler(tmpBuf);
+			free(tmpBuf);
+			memset(buffer, 0, 255);
+		}
+	}
+}
+
+/**
+ * @brief Initialize s6a application message handlers
+ * ready
+ * @param None
+ * @return int SUCCESS or FAIL
+ */
+static int
+init_handlers()
+{
+	if ((ipc_reader_tipc_s6 = create_tipc_socket()) <= 0)
+	{
+		log_msg(LOG_ERROR, "Failed to create IPC Reader tipc socket \n");
+		return -E_FAIL;
+	}
+	if ( bind_tipc_socket(ipc_reader_tipc_s6, s6AppInstanceNum_c) != 1)
+	{
+		log_msg(LOG_ERROR, "failed to bind port name %s\n", strerror(errno));
+		return -E_FAIL;
+	}
+
+	pthread_attr_t attr;
+
+	pthread_attr_init(&attr);
+	/* set the thread detach state */
+	pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+
+	pthread_create(&g_AIR_handler_tid, &attr, &AIR_handler, NULL);
+
+	pthread_attr_destroy(&attr);
+	return 0;
+}
+
+/**
+ * @brief initialize s6a application IPC mechanism, queues
+ * ready
+ * @param None
+ * @return int as SUCCESS or FAIL. exit() in case of error.
+ */
+static int
+init_s6a_ipc()
+{
+	g_Q_mme_S6a_fd = create_tipc_socket();
+	if (g_Q_mme_S6a_fd == -1) {
+		log_msg(LOG_ERROR, "Error in opening writer IPC channel\n");
+		pthread_exit(NULL);
+	}
+	log_msg(LOG_INFO, "S6a response - mme-app TIPC: Connected.\n");
+
+	return 0;
+}
+
+/**
+ * @brief HSS message listener. Listen hss response and delegate to thread pool
+ * case of dummy hss
+ * ready
+ * @param None
+ * @return void
+ */
+void
+s6a_run()
+{
+	unsigned char buf[HSS_RCV_BUF_SIZE];
+	int len;
+
+	/*If using in build perf-hss then start thread to handle it's responses*/
+	if(HSS_FD == g_s6a_cfg.hss_type) {
+		/*Use main thread for ULR or stats etc.*/
+		while(1) {
+			sleep(10);
+		}
+	} else {
+
+	while(1) {
+		bzero(buf, sizeof(buf));
+
+		if ((len = read(g_our_hss_fd, buf,
+						sizeof(struct hss_resp_msg))) < 0) {
+			log_msg(LOG_ERROR, "Error reading hss buff\n");
+	                perror("reading stream message");
+			exit(-1);
+		} else if (len == 0) {
+			log_msg(LOG_ERROR, "Error reading hss buff\n");
+	                perror("reading stream message");
+			exit(-1);
+		}else {
+			unsigned char *tmp_buf = (unsigned char *)
+					calloc(sizeof(char), len);
+			memcpy(tmp_buf, buf, len);
+			log_msg(LOG_INFO, "HSS Received msg len : %d \n",len);
+			insert_job(g_tpool, hss_resp_handler, tmp_buf);
+		}
+	}
+	} /*else - HSS_PERF*/
+}
+
+/**
+ * brief main for s6a application
+ * @param argc and argv
+ * @return int - program's exit code
+ */
+int
+main(int argc, char **argv)
+{
+        
+	memcpy (processName, argv[0], strlen(argv[0]));
+	pid = getpid();
+
+	/*Check cmd line arguments for config file path*/
+	check_args(argc, argv);
+	
+	init_parser("conf/s6a.json");
+	parse_s6a_conf();
+
+	if(HSS_FD == g_s6a_cfg.hss_type){
+		/*Initialize free diameter*/
+		init_fd();
+	} else {
+		init_hss_rpc();
+		/* Initialize thread pool for handling HSS resp*/
+		g_tpool = thread_pool_new(HSS_RESP_THREADPOOL_SIZE);
+		if (g_tpool == NULL) {
+			log_msg(LOG_ERROR, "Error in creating thread pool. \n");
+			return -1;
+		}
+	}
+
+	init_s6a_ipc();
+
+	/*Initialize listner for AIR and ULR from mme-app*/
+	init_handlers();
+
+	s6a_run();
+
+	return 0;
+}