netutils,s1ap: split setting the SCTP options into different functions.

Added option for SO_REUSE_ADDR. Removed sctp_init_socket function.

lib/include/srsran/common/network_utils.h

@@ -74,10 +74,14 @@ public:
   std::string            get_ip() const { return net_utils::get_ip(addr); }
   net_utils::socket_type get_family() const { return net_utils::get_addr_family(sockfd); }
 
+  bool open_socket(net_utils::addr_family ip, net_utils::socket_type socket_type, net_utils::protocol_type protocol);
   bool bind_addr(const char* bind_addr_str, int port);
   bool connect_to(const char* dest_addr_str, int dest_port, sockaddr_in* dest_sockaddr = nullptr);
   bool start_listen();
-  bool open_socket(net_utils::addr_family ip, net_utils::socket_type socket_type, net_utils::protocol_type protocol);
+  bool reuse_addr();
+  bool sctp_subscribe_to_events();
+  bool sctp_set_rto_opts();
+  bool sctp_set_init_msg_opts();
   int  get_socket() const { return sockfd; };
 
 protected:

lib/include/srsran/interfaces/enb_s1ap_interfaces.h

@@ -29,6 +29,7 @@ struct s1ap_args_t {
   std::string gtp_advertise_addr;
   std::string s1c_bind_addr;
   uint16_t    s1c_bind_port;
+  bool        s1c_reuse_addr;
   std::string enb_name;
   uint32_t    ts1_reloc_prep_timeout;
   uint32_t    ts1_reloc_overall_timeout;

lib/src/common/network_utils.cc

@@ -112,72 +112,6 @@ int open_socket(net_utils::addr_family ip_type, net_utils::socket_type socket_ty
   srslog::fetch_basic_logger(LOGSERVICE).debug("Opened %s socket=%d", net_utils::protocol_to_string(protocol), fd);
 
   if (protocol == protocol_type::SCTP) {
-    // Sets the data_io_event to be able to use sendrecv_info
-    // Subscribes to the SCTP_SHUTDOWN event, to handle graceful shutdown
-    // Also subscribes to SCTP_PEER_ADDR_CHANGE, to handle ungraceful shutdown of the link.
-    struct sctp_event_subscribe evnts = {};
-    evnts.sctp_data_io_event          = 1;
-    evnts.sctp_shutdown_event         = 1;
-    evnts.sctp_address_event          = 1;
-    if (setsockopt(fd, IPPROTO_SCTP, SCTP_EVENTS, &evnts, sizeof(evnts)) != 0) {
-      srslog::fetch_basic_logger(LOGSERVICE).error("Failed to subscribe to SCTP_SHUTDOWN event: %s", strerror(errno));
-      perror("Could not register socket to SCTP events\n");
-      close(fd);
-      return -1;
-    }
-
-    /*
-     * Modify SCTP default parameters for quicker detection of broken links.
-     * This includes changes to the SCTP_INITMSG parameters (to control the timeout of the connect() syscall)
-     * And changes to the maximum re-transmission timeout (rto_max), for quicker detection of broken links.
-     */
-    // Set RTO_MAX to quickly detect broken links.
-    sctp_rtoinfo rto_opts;
-    socklen_t    rto_sz    = sizeof(sctp_rtoinfo);
-    rto_opts.srto_assoc_id = 0;
-    if (getsockopt(fd, SOL_SCTP, SCTP_RTOINFO, &rto_opts, &rto_sz) < 0) {
-      printf("Error getting RTO_INFO sockopts\n");
-      close(fd);
-      return -1;
-    }
-
-    rto_opts.srto_max = 6000; // 6 seconds
-
-    srslog::fetch_basic_logger(LOGSERVICE)
-        .debug(
-            "Setting RTO_INFO options on SCTP socket. Association %d, Initial RTO %d, Minimum RTO %d, Maximum RTO %d",
-            rto_opts.srto_assoc_id,
-            rto_opts.srto_initial,
-            rto_opts.srto_min,
-            rto_opts.srto_max);
-
-    if (setsockopt(fd, SOL_SCTP, SCTP_RTOINFO, &rto_opts, rto_sz) < 0) {
-      perror("Error setting RTO_INFO sockopts\n");
-      close(fd);
-      return -1;
-    }
-
-    // Set SCTP INITMSG options to reduce blocking timeout of connect()
-    sctp_initmsg init_opts;
-    socklen_t    init_sz = sizeof(sctp_initmsg);
-    if (getsockopt(fd, SOL_SCTP, SCTP_INITMSG, &init_opts, &init_sz) < 0) {
-      printf("Error getting sockopts\n");
-      close(fd);
-      return -1;
-    }
-
-    init_opts.sinit_max_attempts   = 3;
-    init_opts.sinit_max_init_timeo = 5000; // 5 seconds
-
-    srslog::fetch_basic_logger(LOGSERVICE)
-        .debug("Setting SCTP_INITMSG options on SCTP socket. Max attempts %d, Max init attempts timeout %d",
-               init_opts.sinit_max_attempts,
-               init_opts.sinit_max_init_timeo);
-    if (setsockopt(fd, SOL_SCTP, SCTP_INITMSG, &init_opts, init_sz) < 0) {
-      perror("Error setting SCTP_INITMSG sockopts\n");
-      close(fd);
-      return -1;
-    }
   }
 
   return fd;
@@ -264,6 +198,104 @@ bool start_listen(int fd)
   return true;
 }
 
+bool reuse_addr(int fd)
+{
+  if (fd < 0) {
+    srslog::fetch_basic_logger(LOGSERVICE).error("Trying reuse_addr a closed socket. Socket=%d", fd);
+    return false;
+  }
+
+  int enable = 1;
+  if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(int)) < 0) {
+    srslog::fetch_basic_logger(LOGSERVICE).error("Failed to set SO_REUSEADDR. Socket=%d", fd);
+    return false;
+  }
+  srslog::fetch_basic_logger(LOGSERVICE).debug("Successfully set SO_REUSEADDR. Socket=%d", fd);
+  return true;
+}
+
+bool sctp_subscribe_to_events(int fd)
+{
+  if (fd < 0) {
+    srslog::fetch_basic_logger(LOGSERVICE).error("Trying subscribe to SCTP events on a closed socket. Socket=%d", fd);
+    return false;
+  }
+
+  // Sets the data_io_event to be able to use sendrecv_info
+  // Subscribes to the SCTP_SHUTDOWN event, to handle graceful shutdown
+  // Also subscribes to SCTP_PEER_ADDR_CHANGE, to handle ungraceful shutdown of the link.
+  struct sctp_event_subscribe evnts = {};
+  evnts.sctp_data_io_event          = 1;
+  evnts.sctp_shutdown_event         = 1;
+  evnts.sctp_address_event          = 1;
+  if (setsockopt(fd, IPPROTO_SCTP, SCTP_EVENTS, &evnts, sizeof(evnts)) != 0) {
+    srslog::fetch_basic_logger(LOGSERVICE).error("Failed to subscribe to SCTP_SHUTDOWN event: %s", strerror(errno));
+    perror("Could not register socket to SCTP events\n");
+    close(fd);
+    return false;
+  }
+  return true;
+}
+
+bool sctp_set_rto_opts(int fd)
+{
+  /*
+   * Modify SCTP default parameters for quicker detection of broken links.
+   * This includes changes to the SCTP_INITMSG parameters (to control the timeout of the connect() syscall)
+   * And changes to the maximum re-transmission timeout (rto_max), for quicker detection of broken links.
+   */
+  // Set RTO_MAX to quickly detect broken links.
+  sctp_rtoinfo rto_opts;
+  socklen_t    rto_sz    = sizeof(sctp_rtoinfo);
+  rto_opts.srto_assoc_id = 0;
+  if (getsockopt(fd, SOL_SCTP, SCTP_RTOINFO, &rto_opts, &rto_sz) < 0) {
+    printf("Error getting RTO_INFO sockopts\n");
+    close(fd);
+    return false;
+  }
+
+  rto_opts.srto_max = 6000; // 6 seconds
+
+  srslog::fetch_basic_logger(LOGSERVICE)
+      .debug("Setting RTO_INFO options on SCTP socket. Association %d, Initial RTO %d, Minimum RTO %d, Maximum RTO %d",
+             rto_opts.srto_assoc_id,
+             rto_opts.srto_initial,
+             rto_opts.srto_min,
+             rto_opts.srto_max);
+
+  if (setsockopt(fd, SOL_SCTP, SCTP_RTOINFO, &rto_opts, rto_sz) < 0) {
+    perror("Error setting RTO_INFO sockopts\n");
+    close(fd);
+    return false;
+  }
+  return true;
+}
+
+bool sctp_set_init_msg_opts(int fd)
+{
+  // Set SCTP INITMSG options to reduce blocking timeout of connect()
+  sctp_initmsg init_opts;
+  socklen_t    init_sz = sizeof(sctp_initmsg);
+  if (getsockopt(fd, SOL_SCTP, SCTP_INITMSG, &init_opts, &init_sz) < 0) {
+    printf("Error getting sockopts\n");
+    close(fd);
+    return false;
+  }
+
+  init_opts.sinit_max_attempts   = 3;
+  init_opts.sinit_max_init_timeo = 5000; // 5 seconds
+
+  srslog::fetch_basic_logger(LOGSERVICE)
+      .debug("Setting SCTP_INITMSG options on SCTP socket. Max attempts %d, Max init attempts timeout %d",
+             init_opts.sinit_max_attempts,
+             init_opts.sinit_max_init_timeo);
+  if (setsockopt(fd, SOL_SCTP, SCTP_INITMSG, &init_opts, init_sz) < 0) {
+    perror("Error setting SCTP_INITMSG sockopts\n");
+    close(fd);
+    return false;
+  }
+  return true;
+}
 } // namespace net_utils
 
 /********************************************
@@ -330,25 +362,25 @@ bool unique_socket::start_listen()
   return net_utils::start_listen(sockfd);
 }
 
-/***********************************************************************
+bool unique_socket::reuse_addr()
- *                          SCTP socket
- **********************************************************************/
-
-namespace net_utils {
-
-bool sctp_init_socket(unique_socket* socket, net_utils::socket_type socktype, const char* bind_addr_str, int bind_port)
 {
-  if (not socket->open_socket(net_utils::addr_family::ipv4, socktype, net_utils::protocol_type::SCTP)) {
+  return net_utils::reuse_addr(sockfd);
-    return false;
 }
-  if (not socket->bind_addr(bind_addr_str, bind_port)) {
+
-    socket->close();
+bool unique_socket::sctp_subscribe_to_events()
-    return false;
+{
+  return net_utils::sctp_subscribe_to_events(sockfd);
 }
-  return true;
+
+bool unique_socket::sctp_set_rto_opts()
+{
+  return net_utils::sctp_set_rto_opts(sockfd);
 }
 
-} // namespace net_utils
+bool unique_socket::sctp_set_init_msg_opts()
+{
+  return net_utils::sctp_set_init_msg_opts(sockfd);
+}
 
 /***************************************************************
  *                 Rx Multisocket Handler

lib/test/common/network_utils_test.cc

@@ -52,13 +52,19 @@ int test_socket_handler()
   const char*            server_addr = "127.0.100.1";
   using namespace srsran::net_utils;
 
-  TESTASSERT(sctp_init_socket(&server_socket, socket_type::seqpacket, server_addr, server_port));
+  TESTASSERT(server_socket.open_socket(
+      srsran::net_utils::addr_family::ipv4, socket_type::seqpacket, srsran::net_utils::protocol_type::SCTP));
+  TESTASSERT(server_socket.bind_addr(server_addr, server_port));
   TESTASSERT(server_socket.start_listen());
   logger.info("Listening from fd=%d", server_socket.fd());
 
-  TESTASSERT(sctp_init_socket(&client_socket, socket_type::seqpacket, "127.0.0.1", 0));
+  TESTASSERT(client_socket.open_socket(
-  TESTASSERT(sctp_init_socket(&client_socket2, socket_type::seqpacket, "127.0.0.2", 0));
+      srsran::net_utils::addr_family::ipv4, socket_type::seqpacket, srsran::net_utils::protocol_type::SCTP));
+  TESTASSERT(client_socket.bind_addr("127.0.0.1", 0));
   TESTASSERT(client_socket.connect_to(server_addr, server_port));
+  TESTASSERT(client_socket2.open_socket(
+      srsran::net_utils::addr_family::ipv4, socket_type::seqpacket, srsran::net_utils::protocol_type::SCTP));
+  TESTASSERT(client_socket2.bind_addr("127.0.0.2", 0));
   TESTASSERT(client_socket2.connect_to(server_addr, server_port));
 
   // register server Rx handler
@@ -118,11 +124,17 @@ int test_socket_handler()
 int test_sctp_bind_error()
 {
   srsran::unique_socket sock;
-  TESTASSERT(not srsran::net_utils::sctp_init_socket(
+  TESTASSERT(sock.open_socket(srsran::net_utils::addr_family::ipv4,
-      &sock, srsran::net_utils::socket_type::seqpacket, "1.1.1.1", 8000)); // Bogus IP address
+                              srsran::net_utils::socket_type::seqpacket,
+                              srsran::net_utils::protocol_type::SCTP));
+  TESTASSERT(sock.bind_addr("1.1.1.1", 8000)); // Bogus IP address
                                                // should not be able to bind
-  TESTASSERT(srsran::net_utils::sctp_init_socket(
+
-      &sock, srsran::net_utils::socket_type::seqpacket, "127.0.0.1", 8000)); // Good IP address
+  srsran::unique_socket sock2;
+  TESTASSERT(sock2.open_socket(srsran::net_utils::addr_family::ipv4,
+                               srsran::net_utils::socket_type::seqpacket,
+                               srsran::net_utils::protocol_type::SCTP));
+  TESTASSERT(sock.bind_addr("127.0.0.1", 8000)); // Good IP address
                                                  // should be able to bind
   return SRSRAN_SUCCESS;
 }

srsenb/src/main.cc

@@ -79,6 +79,7 @@ void parse_args(all_args_t* args, int argc, char* argv[])
     ("enb.gtp_advertise_addr", bpo::value<string>(&args->stack.s1ap.gtp_advertise_addr)->default_value(""), "IP address of eNB to advertise for DL GTP-U Traffic")
     ("enb.s1c_bind_addr",      bpo::value<string>(&args->stack.s1ap.s1c_bind_addr)->default_value("192.168.3.1"), "Local IP address to bind for S1AP connection")
     ("enb.s1c_bind_port",      bpo::value<uint16_t>(&args->stack.s1ap.s1c_bind_port)->default_value(0), "Source port for S1AP connection (0 means any)")
+    ("enb.s1c_reuse_addr",     bpo::value<bool>(&args->stack.s1ap.s1c_reuse_addr)->default_value(false), "Use SO_REUSE_ADDR on S1-C interface.")
     ("enb.n_prb",              bpo::value<uint32_t>(&args->enb.n_prb)->default_value(25),               "Number of PRB")
     ("enb.nof_ports",          bpo::value<uint32_t>(&args->enb.nof_ports)->default_value(1),            "Number of ports")
     ("enb.tm",                 bpo::value<uint32_t>(&args->enb.transmission_mode)->default_value(1),    "Transmission mode (1-8)")

srsenb/src/stack/s1ap/s1ap.cc

@@ -491,9 +491,27 @@ bool s1ap::connect_mme()
   using namespace srsran::net_utils;
   logger.info("Connecting to MME %s:%d", args.mme_addr.c_str(), int(MME_PORT));
 
-  // Init SCTP socket and bind it
+  // Open SCTP socket
-  if (not srsran::net_utils::sctp_init_socket(
+  if (not mme_socket.open_socket(
-          &mme_socket, socket_type::seqpacket, args.s1c_bind_addr.c_str(), args.s1c_bind_port)) {
+          srsran::net_utils::addr_family::ipv4, socket_type::seqpacket, srsran::net_utils::protocol_type::SCTP)) {
+    return false;
+  }
+
+  // Set SO_REUSE_ADDR if necessary
+  if (args.s1c_reuse_addr) {
+    if (not mme_socket.reuse_addr()) {
+      mme_socket.close();
+      return false;
+    }
+  }
+
+  mme_socket.sctp_subscribe_to_events();
+  mme_socket.sctp_set_rto_opts();
+  mme_socket.sctp_set_init_msg_opts();
+
+  // Bind socket
+  if (not mme_socket.bind_addr(args.s1c_bind_addr.c_str(), args.s1c_bind_port)) {
+    mme_socket.close();
     return false;
   }
   logger.info("SCTP socket opened. fd=%d", mme_socket.fd());

srsgnb/src/stack/ngap/ngap.cc

@@ -633,12 +633,23 @@ bool ngap::connect_amf()
   using namespace srsran::net_utils;
   logger.info("Connecting to AMF %s:%d", args.amf_addr.c_str(), int(AMF_PORT));
 
-  // Init SCTP socket and bind it
+  // Open SCTP socket
-  if (not sctp_init_socket(&amf_socket, socket_type::seqpacket, args.ngc_bind_addr.c_str(), 0)) {
+  if (not amf_socket.open_socket(
+          srsran::net_utils::addr_family::ipv4, socket_type::seqpacket, srsran::net_utils::protocol_type::SCTP)) {
     return false;
   }
   logger.info("SCTP socket opened. fd=%d", amf_socket.fd());
 
+  amf_socket.sctp_subscribe_to_events();
+  amf_socket.sctp_set_rto_opts();
+  amf_socket.sctp_set_init_msg_opts();
+
+  // Bind socket
+  if (not amf_socket.bind_addr(args.ngc_bind_addr.c_str(), 0)) {
+    amf_socket.close();
+    return false;
+  }
+
   // Connect to the AMF address
   if (not amf_socket.connect_to(args.amf_addr.c_str(), AMF_PORT, &amf_addr)) {
     return false;