UE: add PCO in PDN Connectivity Request message

Add the PCO so that MME allocates the IP address
acccordingly. The protocol ID known as "IP address
allocation via NAS signalling" is assigned.

Reference:
http://www.sharetechnote.com/html/Handbook_LTE_ProtocolConfigurationOption.html

Signed-off-by: Chun-Yeow Yeoh <yeohchunyeow@gmail.com>

openair-cn/NAS/UE/ESM/SAP/esm_send.c

@@ -181,6 +181,28 @@ int esm_send_pdn_connectivity_request(int pti, int is_emergency, int pdn_type,
     }
   }
 
+  /* Add PCO */
+{
+  #define CONFIGURATION_PROTOCOL_PPP          0
+  #define PROTOCOL_ID_IPCP                    0x8021
+  #define PROTOCOL_ID_DNS_SERVER_IPV4_ADDRESS 0x000D
+  #define PROTOCOL_ID_IP_ADDR_NAS_SIGNALING   0x000A
+
+  msg->presencemask |= PDN_CONNECTIVITY_REQUEST_PROTOCOL_CONFIGURATION_OPTIONS_PRESENT;
+  msg->protocolconfigurationoptions.configurationprotol = CONFIGURATION_PROTOCOL_PPP;
+  msg->protocolconfigurationoptions.num_protocol_id_or_container_id = 3;
+  msg->protocolconfigurationoptions.protocolid[0] = PROTOCOL_ID_IPCP;
+  msg->protocolconfigurationoptions.lengthofprotocolid[0] = 16; /* Size of PROTOCOL_ID_IPCP */
+  msg->protocolconfigurationoptions.protocolidcontents[0].value = (uint8_t *)
+  /* PROTOCOL_ID_IPCP data */
+  "\x03\x00\x00\x10\x81\x06\xC0\xA8\x0C\x64\x83\x06\xC0\xA8\x6A\x0C";
+  msg->protocolconfigurationoptions.protocolidcontents[0].length = 16;
+  msg->protocolconfigurationoptions.protocolid[1] = PROTOCOL_ID_DNS_SERVER_IPV4_ADDRESS;
+  msg->protocolconfigurationoptions.lengthofprotocolid[1] = 0x00;
+  msg->protocolconfigurationoptions.protocolid[2] = PROTOCOL_ID_IP_ADDR_NAS_SIGNALING;
+  msg->protocolconfigurationoptions.lengthofprotocolid[2] = 0x00;
+}
+
   LOG_TRACE(INFO, "ESM-SAP   - Send PDN Connectivity Request message "
             "(pti=%d, ebi=%d)",
             msg->proceduretransactionidentity, msg->epsbeareridentity);