GTPU cleanup, adding support for GTPU echo response

lib/include/srslte/upper/gtpu.h

@@ -52,8 +52,8 @@ namespace srslte {
 #define GTPU_HEADER_LEN 8
 
 typedef struct{
-  uint8_t   flags;          // Only support 0x30 - v1, PT1 (GTP), no other flags
+  uint8_t   flags;
-  uint8_t   message_type;   // Only support 0xFF - T-PDU type
+  uint8_t   message_type;
   uint16_t  length;
   uint32_t  teid;
 }gtpu_header_t;

srsenb/hdr/upper/gtpu.h

@@ -124,12 +124,11 @@ private:
   }bearer_map;
   std::map<uint16_t, bearer_map> rnti_bearers;
 
-  // Socket file descriptors
+  // Socket file descriptor
-  int snk_fd;
+  int fd;
-  int src_fd;
 
-  //Threading
   void run_thread();
+  void echo_response(in_addr_t addr, in_port_t port, uint16_t seq);
 
   pthread_mutex_t mutex;
 

srsenb/src/upper/gtpu.cc

@@ -52,35 +52,19 @@ bool gtpu::init(std::string gtp_bind_addr_, std::string mme_addr_, srsenb::pdcp_
 
   pool          = byte_buffer_pool::get_instance();
 
-  // Set up sink socket
+  // Set up socket
-  snk_fd = socket(AF_INET, SOCK_DGRAM, 0);
+  fd = socket(AF_INET, SOCK_DGRAM, 0);
-  if (snk_fd < 0) {
+  if (fd < 0) {
-    gtpu_log->error("Failed to create sink socket\n");
+    gtpu_log->error("Failed to create socket\n");
     return false;
   }
   int enable = 1;
 #if defined (SO_REUSEADDR)
-  if (setsockopt(snk_fd, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(int)) < 0)
+  if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(int)) < 0)
       gtpu_log->error("setsockopt(SO_REUSEADDR) failed\n");
 #endif
 #if defined (SO_REUSEPORT)
-  if (setsockopt(snk_fd, SOL_SOCKET, SO_REUSEPORT, &enable, sizeof(int)) < 0)
+  if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &enable, sizeof(int)) < 0)
-      gtpu_log->error("setsockopt(SO_REUSEPORT) failed\n");
-#endif
-
-
-  // Set up source socket
-  src_fd = socket(AF_INET, SOCK_DGRAM, 0);
-  if (src_fd < 0) {
-    gtpu_log->error("Failed to create source socket\n");
-    return false;
-  }
-#if defined (SO_REUSEADDR)
-  if (setsockopt(src_fd, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(int)) < 0)
-      gtpu_log->error("setsockopt(SO_REUSEADDR) failed\n");
-#endif
-#if defined (SO_REUSEPORT)
-  if (setsockopt(src_fd, SOL_SOCKET, SO_REUSEPORT, &enable, sizeof(int)) < 0)
       gtpu_log->error("setsockopt(SO_REUSEPORT) failed\n");
 #endif
 
@@ -90,7 +74,7 @@ bool gtpu::init(std::string gtp_bind_addr_, std::string mme_addr_, srsenb::pdcp_
   bindaddr.sin_addr.s_addr = inet_addr(gtp_bind_addr.c_str());
   bindaddr.sin_port        = htons(GTPU_PORT);
 
-  if (bind(src_fd, (struct sockaddr *)&bindaddr, sizeof(struct sockaddr_in))) {
+  if (bind(fd, (struct sockaddr *)&bindaddr, sizeof(struct sockaddr_in))) {
     gtpu_log->error("Failed to bind on address %s, port %d\n", gtp_bind_addr.c_str(), GTPU_PORT);
     gtpu_log->console("Failed to bind on address %s, port %d\n", gtp_bind_addr.c_str(), GTPU_PORT);
     return false;
@@ -128,11 +112,8 @@ void gtpu::stop()
     wait_thread_finish();
   }
 
-  if (snk_fd) {
+  if (fd) {
-    close(snk_fd);
+    close(fd);
-  }
-  if (src_fd) {
-    close(src_fd);
   }
 }
 
@@ -152,7 +133,7 @@ void gtpu::write_pdu(uint16_t rnti, uint32_t lcid, srslte::byte_buffer_t* pdu)
   servaddr.sin_port        = htons(GTPU_PORT);
 
   gtpu_write_header(&header, pdu, gtpu_log);
-  if (sendto(snk_fd, pdu->msg, pdu->N_bytes, MSG_EOR, (struct sockaddr*)&servaddr, sizeof(struct sockaddr_in))<0) {
+  if (sendto(fd, pdu->msg, pdu->N_bytes, MSG_EOR, (struct sockaddr*)&servaddr, sizeof(struct sockaddr_in))<0) {
     perror("sendto");
   }
 
@@ -223,6 +204,10 @@ void gtpu::run_thread()
   }
   run_enable = true;
 
+  sockaddr_in client;
+  socklen_t   client_len = sizeof(client);
+  size_t      buflen = SRSENB_MAX_BUFFER_SIZE_BYTES - SRSENB_BUFFER_HEADER_OFFSET;
+
   running=true;
   while(run_enable) {
 
@@ -230,7 +215,7 @@ void gtpu::run_thread()
     gtpu_log->debug("Waiting for read...\n");
     int n = 0;
     do{
-      n = recv(src_fd, pdu->msg, SRSENB_MAX_BUFFER_SIZE_BYTES - SRSENB_BUFFER_HEADER_OFFSET, 0);
+      n = recvfrom(fd, pdu->msg, buflen, 0, (struct sockaddr *)&client, &client_len);
     } while (n == -1 && errno == EAGAIN);
 
     if (n < 0) {
@@ -239,6 +224,16 @@ void gtpu::run_thread()
 
     pdu->N_bytes = (uint32_t) n;
 
+    if(pdu->msg[1] == 0x01) {
+      if(n<10) {
+        continue;
+      }
+      // Echo request - send response
+      uint16_t seq = 0;
+      uint8_to_uint16(&pdu->msg[8], &seq);
+      echo_response(client.sin_addr.s_addr, client.sin_port, seq);
+
+    }else{
       gtpu_header_t header;
       gtpu_read_header(pdu, &header,gtpu_log);
 
@@ -272,9 +267,30 @@ void gtpu::run_thread()
         }
       } while(!pdu);
     }
+  }
   running = false;
 }
 
+void gtpu::echo_response(in_addr_t addr, in_port_t port, uint16_t seq)
+{
+  gtpu_log->info("TX GTPU Echo Response, Seq: %d\n", seq);
+
+  uint8_t resp[12];
+  bzero(resp, 12);
+  resp[0] = 0x32;                 //flags
+  resp[1] = 0x02;                 //type
+  uint16_to_uint8(4,   &resp[2]); //length
+  uint32_to_uint8(0,   &resp[4]); //TEID
+  uint16_to_uint8(seq, &resp[8]); //seq
+
+  struct sockaddr_in servaddr;
+  servaddr.sin_family      = AF_INET;
+  servaddr.sin_addr.s_addr = addr;
+  servaddr.sin_port        = port;
+
+  sendto(fd, resp, 12, MSG_EOR, (struct sockaddr*)&servaddr, sizeof(struct sockaddr_in));
+}
+
 /****************************************************************************
 * TEID to RNIT/LCID helper functions
 ***************************************************************************/