Fixed endianess bug of S-GW address sent to eNB. S-GW now receives upstream user traffic. Starting to strip the gtp-u header.

srsepc/hdr/spgw/spgw.h

@@ -77,6 +77,7 @@ public:
   void handle_modify_bearer_request(struct srslte::gtpc_pdu *mb_req_pdu, struct srslte::gtpc_pdu *mb_resp_pdu);
 
   void handle_sgi_pdu(srslte::byte_buffer_t *msg);
+  void handle_s1u_pdu(srslte::byte_buffer_t *msg);
 
 private:
 

srsepc/src/mme/s1ap.cc

@@ -626,7 +626,7 @@ s1ap::send_initial_context_setup_request(uint32_t mme_ue_s1ap_id, struct srslte:
     return false;
   } 
   erab_ctxt->transportLayerAddress.n_bits = 32; //IPv4
-  uint32_t sgw_s1u_ip = cs_resp->eps_bearer_context_created.s1_u_sgw_f_teid.ipv4;
+  uint32_t sgw_s1u_ip = htonl(cs_resp->eps_bearer_context_created.s1_u_sgw_f_teid.ipv4);
   uint8_t *tmp_ptr =  erab_ctxt->transportLayerAddress.buffer;
   liblte_value_2_bits(sgw_s1u_ip, &tmp_ptr, 32);//FIXME consider ipv6
 

srsepc/src/spgw/spgw.cc

@@ -274,6 +274,7 @@ spgw::run_thread()
           msg->N_bytes = recvfrom(m_s1u, msg->msg, SRSLTE_MAX_BUFFER_SIZE_BYTES, 0, &src_addr, &addrlen );
           //m_spgw_log->console("Received PDU from S1-U. Bytes %d\n", msg->N_bytes);
           //m_spgw_log->debug("Received PDU from S1-U. Bytes %d\n", msg->N_bytes);
+          handle_s1u_pdu(msg);
       }
       if (FD_ISSET(m_sgi_if, &set))
       {
@@ -359,6 +360,13 @@ spgw::handle_sgi_pdu(srslte::byte_buffer_t *msg)
   return;
 }
 
+
+void
+spgw::handle_s1u_pdu(srslte::byte_buffer_t *msg)
+{
+  m_spgw_log->console("Received PDU from S1-U. Bytes=%d\n",msg->N_bytes);
+  return;
+}
 uint64_t
 spgw::get_new_ctrl_teid()
 {