Added functionality for UDP/TCP/SCTP transferring of data over the ASYNC channel interface.

Added selection of interfaces through the configuration file with a new block of statements as follows:

    FLEXSPLIT_INTERFACES :
    {
        DU_INTERFACE_NAME_FOR_F1U           = "lo";
        DU_IPV4_ADDRESS_FOR_F1U             = "127.0.0.1/24";
        DU_PORT_FOR_F1U			    = 2210;

        CU_INTERFACE_NAME_FOR_F1U           = "lo";
        CU_IPV4_ADDRESS_FOR_F1U             = "127.0.0.1";	//Address to search the DU
        CU_PORT_FOR_F1U			    = 2210;

        // One of TCP/UDP/SCTP
        F1_U_TRANSPORT_TYPE 		    = "UDP";
    };

openair2/ENB_APP/enb_config.c

@@ -170,13 +170,14 @@
 #define ENB_CONFIG_STRING_ENB_IPV4_ADDR_FOR_S1U         "ENB_IPV4_ADDRESS_FOR_S1U"
 #define ENB_CONFIG_STRING_ENB_PORT_FOR_S1U              "ENB_PORT_FOR_S1U"
 
-#define ENB_CONFIG_STRING_FLEXSPLIT_CONFIG     		"FLEXSPLIT"
-#define ENB_CONFIG_STRING_PROTO_AGENT_INTERFACE_NAME      "PROTO_AGENT_INTERFACE_NAME"
-#define ENB_CONFIG_STRING_PROTO_AGENT_IPV4_ADDRESS        "PROTO_AGENT_IPV4_ADDRESS"
-#define ENB_CONFIG_STRING_PROTO_AGENT_PORT                "PROTO_AGENT_PORT"
-#define ENB_CONFIG_STRING_PROTO_AGENT_CACHE               "PROTO_AGENT_CACHE"
-
-
+#define ENB_CONFIG_STRING_FLEXSPLIT_INTERFACES_CONFIG	"FLEXSPLIT_INTERFACES"
+#define ENB_CONFIG_STRING_DU_INTERFACE_NAME_FOR_F1U     "DU_INTERFACE_NAME_FOR_F1U"
+#define ENB_CONFIG_STRING_DU_IPV4_ADDRESS_FOR_F1U       "DU_IPV4_ADDRESS_FOR_F1U"
+#define ENB_CONFIG_STRING_DU_PORT_FOR_F1U               "DU_PORT_FOR_F1U"
+#define ENB_CONFIG_STRING_CU_INTERFACE_NAME_FOR_F1U     "CU_INTERFACE_NAME_FOR_F1U"
+#define ENB_CONFIG_STRING_CU_IPV4_ADDRESS_FOR_F1U       "CU_IPV4_ADDRESS_FOR_F1U"
+#define ENB_CONFIG_STRING_CU_PORT_FOR_F1U               "CU_PORT_FOR_F1U"
+#define ENB_CONFIG_STRING_F1_U_TRANSPORT_TYPE           "F1_U_TRANSPORT_TYPE"
 
 #define ENB_CONFIG_STRING_RRH_GW_CONFIG                   "rrh_gw_config"
 #define ENB_CONFIG_STRING_RRH_GW_LOCAL_IF_NAME            "local_if_name"
@@ -635,10 +636,20 @@ const Enb_properties_array_t *enb_config_init(char* lib_config_file_name_pP)
   char             *cidr                          = NULL;
   char             *astring                       = NULL;
 
-  char*             proto_agent_interface_name      = NULL;
-  char*             proto_agent_ipv4_address        = NULL;
-  libconfig_int     proto_agent_port                = 0;
-  char*             proto_agent_cache               = NULL;
+//   char*             proto_agent_interface_name      = NULL;
+//   char*             proto_agent_ipv4_address        = NULL;
+//   libconfig_int     proto_agent_port                = 0;
+//   char*             proto_agent_cache               = NULL;
+
+  char*		    du_interface_name_for_F1U 	  = NULL;
+  char*		    du_ipv4_address_for_F1U 	  = NULL;
+  libconfig_int	    du_port_for_F1U 		  = 0;
+ 
+  char*		    cu_interface_name_for_F1U 	  = NULL;
+  char*		    cu_ipv4_address_for_F1U 	  = NULL;
+  libconfig_int	    cu_port_for_F1U 		  = 0;
+  
+  char*		    transport_type_F1U		  = NULL;
   
   libconfig_int     otg_ue_id                     = 0;
   char*             otg_app_type                  = NULL;
@@ -2355,27 +2366,65 @@ const Enb_properties_array_t *enb_config_init(char* lib_config_file_name_pP)
           }
 
 // PROTO_AGENT configuration
-          subsetting = config_setting_get_member (setting_enb, ENB_CONFIG_STRING_FLEXSPLIT_CONFIG);
-
+          subsetting = config_setting_get_member (setting_enb, ENB_CONFIG_STRING_FLEXSPLIT_INTERFACES_CONFIG);
+	  //LOG_I(PROTO_AGENT, "HERE\n");
           if (subsetting != NULL) {
             if (  (
-                   config_setting_lookup_string( subsetting, ENB_CONFIG_STRING_PROTO_AGENT_INTERFACE_NAME,
-                                                 (const char **)&proto_agent_interface_name)
-                   && config_setting_lookup_string( subsetting, ENB_CONFIG_STRING_PROTO_AGENT_IPV4_ADDRESS,
-                                                    (const char **)&proto_agent_ipv4_address)
-                   && config_setting_lookup_int(subsetting, ENB_CONFIG_STRING_PROTO_AGENT_PORT,
-                                                &proto_agent_port)
-                   && config_setting_lookup_string( subsetting, ENB_CONFIG_STRING_PROTO_AGENT_CACHE,
-                                                    (const char **)&proto_agent_cache)
+                   config_setting_lookup_string( subsetting, ENB_CONFIG_STRING_DU_INTERFACE_NAME_FOR_F1U,
+                                                 (const char **)&du_interface_name_for_F1U)
+                   && config_setting_lookup_string( subsetting, ENB_CONFIG_STRING_DU_IPV4_ADDRESS_FOR_F1U,
+                                                    (const char **)&du_ipv4_address_for_F1U)
+                   && config_setting_lookup_int(subsetting, ENB_CONFIG_STRING_DU_PORT_FOR_F1U,
+                                                &du_port_for_F1U)
+		   && config_setting_lookup_string( subsetting, ENB_CONFIG_STRING_CU_INTERFACE_NAME_FOR_F1U,
+                                                 (const char **)&cu_interface_name_for_F1U)
+                   && config_setting_lookup_string( subsetting, ENB_CONFIG_STRING_CU_IPV4_ADDRESS_FOR_F1U,
+                                                    (const char **)&cu_ipv4_address_for_F1U)
+                   && config_setting_lookup_int(subsetting, ENB_CONFIG_STRING_CU_PORT_FOR_F1U,
+                                                &cu_port_for_F1U)
+                   && config_setting_lookup_string( subsetting, ENB_CONFIG_STRING_F1_U_TRANSPORT_TYPE,
+                                                    (const char **)&transport_type_F1U)
                  )
               ) {
-              enb_properties.properties[enb_properties_index]->proto_agent_interface_name = strdup(proto_agent_interface_name);
-              cidr = proto_agent_ipv4_address;
+              enb_properties.properties[enb_properties_index]->flexsplit_interfaces.du_interface = strdup(du_interface_name_for_F1U);
+              cidr = du_ipv4_address_for_F1U;
+              address = strtok(cidr, "/");
+              enb_properties.properties[enb_properties_index]->flexsplit_interfaces.du_ipv4_address = strdup(address);
+	      enb_properties.properties[enb_properties_index]->flexsplit_interfaces.du_port = du_port_for_F1U;
+
+	      enb_properties.properties[enb_properties_index]->flexsplit_interfaces.cu_interface = strdup(cu_interface_name_for_F1U);
+              cidr = cu_ipv4_address_for_F1U;
               address = strtok(cidr, "/");
-              enb_properties.properties[enb_properties_index]->proto_agent_ipv4_address = strdup(address);
+              enb_properties.properties[enb_properties_index]->flexsplit_interfaces.cu_ipv4_address = strdup(address);
+	      enb_properties.properties[enb_properties_index]->flexsplit_interfaces.cu_port = cu_port_for_F1U;
+	      
+	      if (strcmp(transport_type_F1U, "UDP") == 0)
+	      {
+		  enb_properties.properties[enb_properties_index]->flexsplit_interfaces.udp = 1;
+		  enb_properties.properties[enb_properties_index]->flexsplit_interfaces.tcp = 0;
+		  enb_properties.properties[enb_properties_index]->flexsplit_interfaces.sctp = 0;
+	      }
+	      else if (strcmp(transport_type_F1U, "TCP") == 0)
+	      {
+		  enb_properties.properties[enb_properties_index]->flexsplit_interfaces.udp = 0;
+		  enb_properties.properties[enb_properties_index]->flexsplit_interfaces.tcp = 1;
+		  enb_properties.properties[enb_properties_index]->flexsplit_interfaces.sctp = 0;		
+	      }
+	      
+	     else if (strcmp(transport_type_F1U, "SCTP") == 0)
+	     {
+		  enb_properties.properties[enb_properties_index]->flexsplit_interfaces.udp = 0;
+		  enb_properties.properties[enb_properties_index]->flexsplit_interfaces.tcp = 0;
+		  enb_properties.properties[enb_properties_index]->flexsplit_interfaces.sctp = 1;
+	     }
+	     else
+	     {
+		  // Will be handled by the proto agent functionality
+	          enb_properties.properties[enb_properties_index]->flexsplit_interfaces.udp = 0;
+		  enb_properties.properties[enb_properties_index]->flexsplit_interfaces.tcp = 0;
+		  enb_properties.properties[enb_properties_index]->flexsplit_interfaces.sctp = 0;	       
+	     }
 	      
-              enb_properties.properties[enb_properties_index]->proto_agent_port = proto_agent_port;
-              enb_properties.properties[enb_properties_index]->proto_agent_cache = strdup(proto_agent_cache);
             }
           }
 

openair2/ENB_APP/enb_config.h

@@ -78,6 +78,22 @@ typedef struct mme_ip_address_s {
   char     *ipv6_address;
 } mme_ip_address_t;
 
+
+typedef struct flexplit_interfaces {
+  char *du_interface;
+  char *du_ipv4_address;
+  uint16_t du_port;
+  
+  char *cu_interface;
+  char *cu_ipv4_address;
+  uint16_t cu_port;
+  
+  unsigned tcp:1;
+  unsigned udp:1;
+  unsigned sctp:1;
+  
+}flexsplit_interfaces_t;
+
 typedef struct rrh_gw_config_s {
   unsigned  udp:1;
   unsigned  raw:1;
@@ -221,11 +237,7 @@ typedef struct Enb_properties_s {
   char               *enb_interface_name_for_S1_MME;
   in_addr_t           enb_ipv4_address_for_S1_MME;
 
-
-  char               *proto_agent_interface_name;
-  in_addr_t           proto_agent_ipv4_address;
-  tcp_udp_port_t      proto_agent_port;
-  char               *proto_agent_cache;
+  flexsplit_interfaces_t flexsplit_interfaces;
 
 
 

openair2/LAYER2/PDCP_v10.1.0/pdcp.c

@@ -374,11 +374,12 @@ boolean_t pdcp_data_req(
   enb_properties_p = enb_config_get();
 
   static int agent_started = 1;
-
+/*
   if (agent_started == 1)
   {
+     LOG_I(PROTO_AGENT,"PDCP: starting client side with mod_id %d \n",ctxt_pP->module_id);
      agent_started = proto_agent_start(ctxt_pP->module_id, enb_properties_p);
-  }
+  }*/
   
 
   if (pdcp_pdu_p!=NULL)
@@ -389,7 +390,7 @@ boolean_t pdcp_data_req(
   }
   else
   {
-    // It should never get here
+    //It should never get here
     rlc_status = rlc_data_req(ctxt_pP, srb_flagP, MBMS_FLAG_NO, rb_idP, muiP, confirmP, pdcp_pdu_size, pdcp_pdu_p);
   }
   }
@@ -922,6 +923,23 @@ pdcp_run (
   protocol_ctxt_t  ctxt;
 #endif
   
+  static int agent_started = 1;
+
+  
+  Enb_properties_array_t *enb_properties_p  = NULL;
+
+  enb_properties_p = enb_config_get();
+  
+  if (agent_started == 1)
+  {
+    LOG_I(PROTO_AGENT,"Starting the PDCP instance\n");
+    //LOG_I(PROTO_AGENT,"PDCP: starting client side with mod_id %d \n",ctxt_pP->module_id);
+
+     agent_started = proto_agent_start(ctxt_pP->module_id, enb_properties_p);
+  }
+  
+  
+
   if (ctxt_pP->enb_flag) {
     start_meas(&eNB_pdcp_stats[ctxt_pP->module_id].pdcp_run);
   } else {

openair2/LAYER2/PROTO_AGENT/proto_agent_async.c

@@ -37,29 +37,49 @@
 #include "proto_agent_async.h"
 #include "proto_agent_defs.h"
 
+
 #include "log.h"
 
+uint16_t proto_udp = 0;
+uint16_t proto_tcp = 0;
+uint16_t proto_sctp = 0;
 
-proto_agent_async_channel_t * proto_server_async_channel_info(mid_t mod_id, char *dst_ip, uint16_t dst_port) {
+proto_agent_async_channel_t * proto_server_async_channel_info(mid_t mod_id, char *dst_ip, uint16_t dst_port, const char* type, const char *peer_addr) {
 
   proto_agent_async_channel_t *channel;
   channel = (proto_agent_async_channel_t *) malloc(sizeof(proto_agent_channel_t));
 
+  channel->port = dst_port;
+  channel->peer_addr = NULL;
+  
   if (channel == NULL)
     goto error;
 
   channel->enb_id = mod_id;
   /*Create a socket*/
-  printf("Starting async server\n");
+  if (strcmp(type, "TCP") == 0)
+  {
+    proto_tcp = 1;
     channel->link = new_link_server(dst_port);
-  //channel->link = NULL;
-  printf("Started async server\n");
-  if (channel->link == NULL) goto error;
+    channel->type = 0;
+  }
+  else if (strcmp(type, "UDP") == 0)
+  {
+    proto_udp = 1;
+    //channel->link = new_udp_link_server(dst_port);
+    channel->link = new_link_udp_server(dst_port);
+    channel->type = 1;
+    channel->peer_addr = peer_addr;
+  }
+  else if (strcmp(type, "SCTP") == 0)
+  {
+    proto_sctp = 1;
+    //channel->link = new_sctp_link_server(dst_port);
+    channel->link = new_link_sctp_server(dst_port);
+    channel->type = 2;
+  }
   
-  LOG_I(PROTO_AGENT,"starting proto agent server for module id %d on ipv4 %s, port %d\n",  
-	channel->enb_id,
-	dst_ip,
-	dst_port);
+  if (channel->link == NULL) goto error;
   
    /* 
    * create a message queue
@@ -73,7 +93,7 @@ proto_agent_async_channel_t * proto_server_async_channel_info(mid_t mod_id, char
    /* 
    * create a link manager 
    */  
-  channel->manager = create_link_manager(channel->send_queue, channel->receive_queue, channel->link);
+  channel->manager = create_link_manager(channel->send_queue, channel->receive_queue, channel->link, channel->type, channel->peer_addr, channel->port);
   if (channel->manager == NULL) goto error;
   
   return channel;
@@ -84,25 +104,41 @@ proto_agent_async_channel_t * proto_server_async_channel_info(mid_t mod_id, char
 }
 
 
-proto_agent_async_channel_t * proto_agent_async_channel_info(mid_t mod_id, char *dst_ip, uint16_t dst_port) {
+proto_agent_async_channel_t * proto_agent_async_channel_info(mid_t mod_id, char *dst_ip, uint16_t dst_port, const char* type, const char *peer_addr) {
 
   proto_agent_async_channel_t *channel;
   channel = (proto_agent_async_channel_t *) malloc(sizeof(proto_agent_channel_t));
   
+  channel->port = dst_port;
+  channel->peer_addr = NULL;
+  
   if (channel == NULL)
     goto error;
 
   channel->enb_id = mod_id;
   /*Create a socket*/
+  if (strcmp(type, "TCP") == 0)
+  {
+    proto_tcp = 1;
     channel->link = new_link_client(dst_ip, dst_port);
-
-  if (channel->link == NULL) goto error;
+    channel->type = 0;
+  }
+  else if (strcmp(type, "UDP") == 0)
+  {
+    proto_udp = 1;
+    channel->link = new_link_udp_client(dst_ip, dst_port);
+    channel->type = 1;
+    channel->peer_addr = peer_addr;
+  }
+  else if (strcmp(type, "SCTP") == 0)
+  {
+    proto_sctp = 1;
+    channel->link = new_link_sctp_client(dst_ip, dst_port);;
+    channel->type = 2;
+  }
   
  
-  LOG_I(PROTO_AGENT,"starting proto agent client for module id %d on ipv4 %s, port %d\n",  
-	channel->enb_id,
-	dst_ip,
-	dst_port);
+  if (channel->link == NULL) goto error;
   
    /* 
    * create a message queue
@@ -116,13 +152,13 @@ proto_agent_async_channel_t * proto_agent_async_channel_info(mid_t mod_id, char
    /* 
    * create a link manager 
    */  
-  channel->manager = create_link_manager(channel->send_queue, channel->receive_queue, channel->link);
+  channel->manager = create_link_manager(channel->send_queue, channel->receive_queue, channel->link, channel->type, channel->peer_addr, channel->port);
   if (channel->manager == NULL) goto error;
   
   return channel;
 
  error:
-  LOG_I(PROTO_AGENT,"there was an error\n");
+  LOG_E(PROTO_AGENT,"there was an error\n");
   return 1;
 }
 

openair2/LAYER2/PROTO_AGENT/proto_agent_async.h

@@ -41,14 +41,17 @@
 
 typedef struct {
   mid_t            enb_id;
+  uint16_t         type; // 0-> TCP, 1-> UDP, 2->SCTP
+  char 		  *peer_addr;
+  int		   port;
   socket_link_t   *link;
   message_queue_t *send_queue;
   message_queue_t *receive_queue;
   link_manager_t  *manager;
 } proto_agent_async_channel_t;
 
-proto_agent_async_channel_t * proto_agent_async_channel_info(mid_t mod_id, char *dst_ip, uint16_t dst_port);
-proto_agent_async_channel_t * proto_server_async_channel_info(mid_t mod_id, char *dst_ip, uint16_t dst_port);
+proto_agent_async_channel_t * proto_agent_async_channel_info(mid_t mod_id, char *dst_ip, uint16_t dst_port, const char* type, const char *peer_addr);
+proto_agent_async_channel_t * proto_server_async_channel_info(mid_t mod_id, char *dst_ip, uint16_t dst_port, const char* type, const char *peer_addr);
 
 int proto_agent_async_msg_send(void *data, int size, int priority, void *channel_info);
 

openair2/LAYER2/PROTO_AGENT/proto_agent_common.c

@@ -254,6 +254,7 @@ int proto_agent_get_ack_result(mid_t mod_id, const void *params, Protocol__Flexs
   Protocol__FspRlcDataReqAck *data_ack = input->data_req_ack;
   result = data_ack->result;
   ack_result = result;
+  return 0;
 
 }
 

openair2/LAYER2/PROTO_AGENT/proto_agent_handler.c

@@ -40,7 +40,7 @@
 #include "assertions.h"
 
 proto_agent_message_decoded_callback agent_messages_callback[][3] = {
-  {proto_agent_hello, proto_agent_hello, 0},
+  {proto_agent_hello, 0, 0},
   {proto_agent_echo_reply, 0, 0},
   {0, just_print, 0},
   {proto_agent_pdcp_data_req_ack, 0, 0},
@@ -100,6 +100,7 @@ Protocol__FlexsplitMessage* proto_agent_handle_message (mid_t mod_id,
 
   if ( err_code < 0 )
   {
+    LOG_I(PROTO_AGENT, "decoded_message case : %d, direction : %d \n", decoded_message->msg_case-1, decoded_message->msg_dir-1);
     goto error;
   }
   else if (err_code == 1) 

openair2/LAYER2/PROTO_AGENT/proto_agent_net_comm.h

@@ -45,6 +45,7 @@ typedef struct proto_agent_channel_s {
   RB_ENTRY(proto_agent_channel_s) entry;
 int channel_id;
 void *channel_info;
+uint16_t type; // 0-> TCP, 1-> UDP, 2->SCTP
 /*Callbacks for channel message Tx and Rx*/
 int (*msg_send)(void *data, int size, int priority, void *channel_info);
 int (*msg_recv)(void **data, int *size, int *priority, void *channel_info);

openair2/UTIL/ASYNC_IF/link_manager.c

@@ -57,7 +57,7 @@ static void *link_manager_sender_thread(void *_manager)
 
   while (manager->run) {
     while (message_get(manager->send_queue, &data, &size, &priority) == 0) {
-      link_send_packet(manager->socket_link, data, size);
+      link_send_packet(manager->socket_link, data, size, manager->type, manager->peer_addr, manager->port);
       free(data);
     }
     //    if (message_get(manager->send_queue, &data, &size, &priority))
@@ -86,7 +86,7 @@ static void *link_manager_receiver_thread(void *_manager)
   LOG_D(MAC, "starting link manager receiver thread\n");
 
   while (manager->run) {
-    if (link_receive_packet(manager->socket_link, &data, &size))
+    if (link_receive_packet(manager->socket_link, &data, &size, manager->type, manager->peer_addr, manager->port))
       goto error;
     /* todo: priority */
     if (message_put(manager->receive_queue, data, size, 0))
@@ -105,7 +105,10 @@ error:
 link_manager_t *create_link_manager(
         message_queue_t *send_queue,
         message_queue_t *receive_queue,
-        socket_link_t   *link)
+        socket_link_t   *link,
+	uint16_t 	type,
+	char 		*peer_addr,
+ 	int		port	  )
 {
   link_manager_t *ret = NULL;
   pthread_attr_t attr;
@@ -120,6 +123,9 @@ link_manager_t *create_link_manager(
   ret->send_queue = send_queue;
   ret->receive_queue = receive_queue;
   ret->socket_link = link;
+  ret->type = type;
+  ret->peer_addr = peer_addr;
+  ret->port = port;
   ret->run = 1;
 
   if (pthread_attr_init(&attr))

openair2/UTIL/ASYNC_IF/link_manager.h

@@ -41,6 +41,7 @@
 #include "message_queue.h"
 //#include "ringbuffer_queue.h"
 #include "socket_link.h"
+#include <stdint.h>
 
 #include <pthread.h>
 
@@ -52,6 +53,9 @@ typedef struct {
   message_queue_t *send_queue;
   message_queue_t *receive_queue;
   socket_link_t   *socket_link;
+  uint16_t	  type;
+  char 		  *peer_addr;
+  int		  port;
   pthread_t       sender;
   pthread_t       receiver;
   volatile int    run;
@@ -60,7 +64,11 @@ typedef struct {
 link_manager_t *create_link_manager(
         message_queue_t *send_queue,
         message_queue_t *receive_queue,
-        socket_link_t   *link);
+        socket_link_t   *link,
+	uint16_t 	type,
+	char 		*peer_addr,
+	int 		port
+ 				  );
 void destroy_link_manager(link_manager_t *);
 
 #ifdef __cplusplus

openair2/UTIL/ASYNC_IF/message_queue.h

@@ -38,6 +38,7 @@
 #ifndef MESSAGE_QUEUE_H
 #define MESSAGE_QUEUE_H
 
+#include <stdint.h>
 #include <pthread.h>
 
 #ifdef __cplusplus
@@ -48,6 +49,7 @@ typedef struct message_t {
   void *data;
   int  size;
   int  priority;
+  uint16_t type;
   struct message_t *next;
 } message_t;
 

openair2/UTIL/ASYNC_IF/socket_link.c

@@ -48,6 +48,7 @@
 #include <netinet/ip.h>
 #include <netinet/tcp.h>
 #include <netinet/udp.h>
+#include <netinet/sctp.h>
 #include <arpa/inet.h>
 #include <stdint.h>
 
@@ -106,7 +107,6 @@ socket_link_t *new_link_server(int port)
     LOG_E(PROTO_AGENT, "%s:%d: accept: %s\n", __FILE__, __LINE__, strerror(errno));
     goto error;
   }
-  printf("Accepted new connection from client\n");
   close(socket_server);
 
   LOG_D(PROTO_AGENT, "connection from %s:%d\n", inet_ntoa(addr.sin_addr), ntohs(addr.sin_port));
@@ -169,6 +169,202 @@ error:
   return NULL;
 }
 
+
+socket_link_t *new_link_udp_server(int port){
+
+  socket_link_t  *ret = NULL;
+
+  struct sockaddr_in si_me, si_other;
+  int socket_server, i, slen = sizeof(si_other) , recv_bytes;
+  char buf[1500];
+
+  ret = calloc(1, sizeof(socket_link_t));
+  if (ret == NULL) {
+    LOG_D(PROTO_AGENT, "%s:%d: out of memory\n", __FILE__, __LINE__);
+    goto error;
+  }
+  ret->socket_fd = -1;
+
+  LOG_D(PROTO_AGENT, "create a new udp link server socket at port %d\n", port);
+
+  //create a UDP socket
+  if ((socket_server=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1) {
+        goto error;
+  }
+
+  // zero out the structure
+  memset((char *) &si_me, 0, sizeof(si_me));
+
+  si_me.sin_family = AF_INET;
+  si_me.sin_port = htons(port);
+  si_me.sin_addr.s_addr = htonl(INADDR_ANY);
+
+  //bind socket to port
+  if( bind(socket_server , (struct sockaddr*)&si_me, sizeof(si_me) ) == -1) {
+        goto error;
+  }
+  ret->socket_fd = socket_server;
+  ret->peer_port = 0;
+  return ret;
+  
+error:
+  close(socket_server);
+  if (ret != NULL) close(ret->socket_fd);
+  free(ret);
+  LOG_E(PROTO_AGENT, "ERROR in new_link_udp_server (see above), returning NULL\n");
+  return NULL;
+}
+
+
+socket_link_t *new_link_udp_client(char *server, int port){
+
+  socket_link_t      *ret = NULL;
+  ret = calloc(1, sizeof(socket_link_t));
+  if (ret == NULL) {
+    LOG_E(MAC, "%s:%d: out of memory\n", __FILE__, __LINE__);
+    //goto error;
+  }
+  ret->socket_fd = -1;
+
+  struct sockaddr_in si_other, server_info;
+  int s, i, slen=sizeof(si_other);
+  char buf[1500];
+  char message[1500];
+ 
+  if ( (s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1){
+        goto error;
+  }
+ 
+  memset((char *) &si_other, 0, sizeof(si_other));
+  si_other.sin_family = AF_INET;
+  si_other.sin_port = 0; //htons(port);
+  
+
+  
+  if (inet_aton(server, &si_other.sin_addr) == 0){
+        fprintf(stderr, "inet_aton() failed\n");
+        goto error;
+  }
+  connect(s, (struct sockaddr *)&si_other, sizeof(si_other)); 
+  
+  getsockname(s, (struct sockaddr *)&si_other, &slen);
+
+  ret->socket_fd = s;
+  ret->peer_port = port; //ntohs(si_other.sin_port);
+ 
+  return ret;
+error:
+  if (ret != NULL) close(ret->socket_fd);
+  free(ret);
+  LOG_E(MAC, "ERROR in new_link_udp_client (see above), returning NULL\n");
+  return NULL;
+}
+
+
+socket_link_t *new_link_sctp_server(int port)
+{
+
+  socket_link_t  *ret = NULL;
+  ret = calloc(1, sizeof(socket_link_t));
+  if (ret == NULL) {
+    LOG_D(PROTO_AGENT, "%s:%d: out of memory\n", __FILE__, __LINE__);
+    goto error;
+  }
+  ret->socket_fd = -1;
+
+  int listenSock, temp;
+  struct sockaddr_in servaddr;
+ 
+  listenSock = socket (AF_INET, SOCK_STREAM, IPPROTO_SCTP);
+  if(listenSock == -1)
+  {
+      perror("socket()");
+      exit(1);
+  }
+ 
+  bzero ((void *) &servaddr, sizeof (servaddr));
+  servaddr.sin_family = AF_INET;
+  servaddr.sin_addr.s_addr = htonl (INADDR_ANY);
+  servaddr.sin_port = htons(port);
+ 
+  temp = bind (listenSock, (struct sockaddr *) &servaddr, sizeof (servaddr));
+ 
+  if(temp == -1 )
+  {
+      perror("bind()");
+      close(listenSock);
+      exit(1);
+  }
+ 
+  temp = listen (listenSock, 5);
+    if(temp == -1 )
+  {
+      perror("listen()");
+      close(listenSock);
+      exit(1);
+  }
+
+  ret->socket_fd = accept (listenSock, (struct sockaddr *) NULL, (int *) NULL);
+  
+  return ret;
+
+error:
+  close(listenSock);
+  if (ret != NULL) close(ret->socket_fd);
+  free(ret);
+  LOG_E(PROTO_AGENT, "ERROR in new_link_sctp_server (see above), returning NULL\n");
+  return NULL;
+}
+
+socket_link_t *new_link_sctp_client(char *server, int port)
+{
+
+  socket_link_t      *ret = NULL;
+  ret = calloc(1, sizeof(socket_link_t));
+  if (ret == NULL) {
+    LOG_D(PROTO_AGENT, "%s:%d: out of memory\n", __FILE__, __LINE__);
+    goto error;
+  }
+  ret->socket_fd = -1;
+
+  int temp;
+  struct sockaddr_in servaddr;
+    
+  ret->socket_fd = socket (AF_INET, SOCK_STREAM, IPPROTO_SCTP);
+ 
+  if (ret->socket_fd == -1)
+  {
+      perror("socket()");
+      exit(1);
+  }
+ 
+  bzero ((void *) &servaddr, sizeof (servaddr));
+  servaddr.sin_family = AF_INET;
+  servaddr.sin_port = htons (port);
+  if (inet_aton(server, &servaddr.sin_addr) == 0) {
+    LOG_E(PROTO_AGENT, "invalid IP address '%s', use a.b.c.d notation\n", server);
+    goto error;
+  }
+
+  temp = connect (ret->socket_fd, (struct sockaddr *) &servaddr, sizeof (servaddr));
+ 
+  if (temp == -1)
+  {
+      perror("connect()");
+      close(ret->socket_fd);
+      exit(1);
+  }
+
+  return ret;
+
+error:
+  if (ret != NULL) close(ret->socket_fd);
+  free(ret);
+  LOG_E(MAC, "ERROR in new_link_sctp_client (see above), returning NULL\n");
+  return NULL;
+}
+
+
 /*
  * return -1 on error and 0 if the sending was fine
  */
@@ -192,6 +388,43 @@ error:
   return -1;
 }
 
+static int socket_udp_send(int socket_fd, void *buf, int size, char *peer_addr, int port)
+{
+  
+  struct sockaddr_in si_other;
+  int slen = sizeof(si_other);
+  char *s = buf;
+  int   l;
+  int my_socket;
+  
+  LOG_D(PROTO_AGENT,"UDP send\n");
+
+  my_socket = socket_fd;
+  memset((char *) &si_other, 0, sizeof(si_other));
+  si_other.sin_family = AF_INET;
+  si_other.sin_port = htons(port);
+     
+  if (inet_aton(peer_addr , &si_other.sin_addr) == 0) 
+  {
+      fprintf(stderr, "inet_aton() failed\n");
+      exit(1);
+  }
+
+  while (size) {
+    l = sendto(my_socket, s, size, 0, (struct sockaddr *) &si_other, slen);
+    if (l == -1) goto error;
+    if (l == 0) { LOG_E(PROTO_AGENT, "%s:%d: this cannot happen, normally...\n", __FILE__, __LINE__); abort(); }
+    size -= l;
+    s += l;
+  }
+  
+  return 0;
+error:
+  LOG_E(PROTO_AGENT, "socket_udp_send: ERROR: %s\n", strerror(errno));
+  return -1;
+}
+
+
 /*
  * return -1 on error and 0 if the receiving was fine
  */
@@ -219,10 +452,44 @@ socket_closed:
   return -1;
 }
 
+/*
+ * return -1 on error and 0 if the receiving was fine
+ */
+static int socket_udp_receive(int socket_fd, void *buf, int size)
+{
+  LOG_D(PROTO_AGENT,"UDP RECEIVE\n");
+
+  struct sockaddr_in client;
+  int slen = sizeof(client);
+  char *s = buf;
+  int   l;
+
+  while (size) {
+    l = recvfrom(socket_fd, s, size, 0, (struct sockaddr *) &client, &slen);
+    getsockname(s, (struct sockaddr *)&client, &slen);
+    LOG_D(PROTO_AGENT, "Got message from src port: %u\n", ntohs(client.sin_port));
+    if (l == -1) goto error;
+    if (l == 0) goto socket_closed;
+    size -= l;
+    s += l;
+  }
+
+  return ntohs(client.sin_port);
+
+error:
+  LOG_E(MAC, "socket_udp_receive: ERROR: %s\n", strerror(errno));
+  return -1;
+
+socket_closed:
+  LOG_E(MAC, "socket_udp_receive: socket closed\n");
+  return -1;
+}
+
+
 /*
  * return -1 on error and 0 if the sending was fine
  */
-int link_send_packet(socket_link_t *link, void *data, int size)
+int link_send_packet(socket_link_t *link, void *data, int size, uint16_t proto_type, char *peer_addr, int port)
 {
   char sizebuf[4];
   int32_t s = size;
@@ -233,6 +500,8 @@ int link_send_packet(socket_link_t *link, void *data, int size)
   sizebuf[2] = (s >> 8) & 255;
   sizebuf[3] = s & 255;
 
+  if ((proto_type == 0) || (proto_type == 2))
+  {
     if (socket_send(link->socket_fd, sizebuf, 4) == -1)
       goto error;
           
@@ -243,6 +512,25 @@ int link_send_packet(socket_link_t *link, void *data, int size)
 
     link->bytes_sent += size;
     link->packets_sent++;
+  }
+  else if (proto_type == 1 )
+  {
+    while (link->peer_port == 0)
+    {
+      sleep(0.1);
+    }
+    LOG_D(PROTO_AGENT, "peer port is %d", link->peer_port);
+    if (socket_udp_send(link->socket_fd, sizebuf, 4, peer_addr, link->peer_port) == -1)
+      goto error;
+      
+    link->bytes_sent += 4;
+
+    if (socket_udp_send(link->socket_fd, data, size, peer_addr, link->peer_port) == -1)
+      goto error;
+
+    link->bytes_sent += size;
+    link->packets_sent++;
+  }
 
   return 0;
 
@@ -253,15 +541,27 @@ error:
 /*
  * return -1 on error and 0 if the sending was fine
  */
-int link_receive_packet(socket_link_t *link, void **ret_data, int *ret_size)
+int link_receive_packet(socket_link_t *link, void **ret_data, int *ret_size, uint16_t proto_type, char *peer_addr, int port)
 {
   unsigned char sizebuf[4];
   int32_t       size;
   void          *data = NULL;
+  int 		peer_port = 0;
 
+  if ((proto_type == 0) || (proto_type == 2))
+  {
   /* received the size first, maximum is 2^31 bytes */
     if (socket_receive(link->socket_fd, sizebuf, 4) == -1)
       goto error;
+  }
+  else if (proto_type == 1)
+  {
+      /* received the size first, maximum is 2^31 bytes */
+    peer_port = socket_udp_receive(link->socket_fd, sizebuf, 4);
+      if ( peer_port == -1)
+	goto error;
+    if (link->peer_port == 0) link->peer_port = peer_port;
+  }
   
   size = (sizebuf[0] << 24) |
          (sizebuf[1] << 16) |
@@ -278,9 +578,16 @@ int link_receive_packet(socket_link_t *link, void **ret_data, int *ret_size)
     goto error;
   }
   
+  if ((proto_type == 0) || (proto_type == 2))
+  {
     if (socket_receive(link->socket_fd, data, size) == -1)
       goto error;
-
+  }
+  else if (proto_type == 1)
+  {
+    if (socket_udp_receive(link->socket_fd, data, size) == -1)
+      goto error;
+  }
   link->bytes_received += size;
   link->packets_received++;
   *ret_data = data;

openair2/UTIL/ASYNC_IF/socket_link.h

@@ -44,8 +44,10 @@
 extern "C" {
 #endif
 
+  
 typedef struct {
   int      socket_fd;
+  int	   peer_port;
   uint64_t bytes_sent;
   uint64_t packets_sent;
   uint64_t bytes_received;
@@ -54,8 +56,12 @@ typedef struct {
 
 socket_link_t *new_link_server(int port);
 socket_link_t *new_link_client(char *server, int port);
-int link_send_packet(socket_link_t *link, void *data, int size);
-int link_receive_packet(socket_link_t *link, void **data, int *size);
+socket_link_t *new_link_udp_server(int port);
+socket_link_t *new_link_udp_client(char *server, int port);
+socket_link_t *new_link_sctp_server(int port);
+socket_link_t *new_link_sctp_client(char *server, int port);
+int link_send_packet(socket_link_t *link, void *data, int size, uint16_t proto_type, char *peer_addr, int port);
+int link_receive_packet(socket_link_t *link, void **data, int *size, uint16_t proto_type, char *peer_addr, int port);
 int close_link(socket_link_t *link);
 
 #ifdef __cplusplus

targets/PROJECTS/GENERIC-LTE-EPC/CONF/enb.band7.generic.oaisim.local_no_mme.conf

@@ -118,6 +118,20 @@ eNBs =
         ENB_PORT_FOR_S1U                         = 2153; # Spec 2152
     };
 
+    FLEXSPLIT_INTERFACES :
+    {
+        DU_INTERFACE_NAME_FOR_F1U           = "eth0";
+        DU_IPV4_ADDRESS_FOR_F1U             = "127.0.0.1/24";
+        DU_PORT_FOR_F1U			    = 2210;
+        
+        CU_INTERFACE_NAME_FOR_F1U           = "lo";
+        CU_IPV4_ADDRESS_FOR_F1U             = "10.64.45.62";	//Address to search the DU
+        CU_PORT_FOR_F1U			    = 2210;
+        
+        // One of TCP/UDP/SCTP
+        F1_U_TRANSPORT_TYPE 		    = "UDP";
+    };
+    
     log_config :
     {
       global_log_level                      ="trace";