Merge pull request #4104 from GregorR/natt

NAT traversal

Makefile.common

@@ -1086,6 +1086,7 @@ ifeq ($(HAVE_NETWORKING), 1)
    OBJ += $(LIBRETRO_COMM_DIR)/net/net_compat.o \
           $(LIBRETRO_COMM_DIR)/net/net_http.o \
           $(LIBRETRO_COMM_DIR)/net/net_socket.o \
+	  $(LIBRETRO_COMM_DIR)/net/net_natt.o \
           network/net_http_special.o \
           tasks/task_http.o
 
@@ -1123,6 +1124,10 @@ ifeq ($(HAVE_NETWORKING), 1)
       OBJ += input/input_remote.o \
              cores/libretro-net-retropad/net_retropad_core.o
    endif
+
+   ifeq ($(HAVE_MINIUPNPC), 1)
+      LIBS += -lminiupnpc
+   endif
 endif
 
 ifneq ($(findstring Win32,$(OS)),)

configuration.c

@@ -800,6 +800,7 @@ static int populate_settings_bool(settings_t *settings, struct config_bool_setti
 #endif
 #ifdef HAVE_NETWORKING
    SETTING_BOOL("netplay_spectator_mode_enable",&settings->netplay.is_spectate, false, false /* TODO */, false);
+   SETTING_BOOL("netplay_nat_traversal",       &settings->netplay.nat_traversal, true, true, false);
 #endif
    SETTING_BOOL("block_sram_overwrite",         &settings->block_sram_overwrite, true, block_sram_overwrite, false);
    SETTING_BOOL("savestate_auto_index",         &settings->savestate_auto_index, true, savestate_auto_index, false);
@@ -922,7 +923,7 @@ static int populate_settings_int(settings_t *settings, struct config_int_setting
 #ifdef HAVE_NETWORKING
    SETTING_INT("netplay_ip_port",              &settings->netplay.port, false, 0 /* TODO */, false);
    SETTING_INT("netplay_delay_frames",         &settings->netplay.sync_frames, true, 16, false);
-   SETTING_INT("netplay_check_frames",         &settings->netplay.check_frames, false, 30, false);
+   SETTING_INT("netplay_check_frames",         &settings->netplay.check_frames, true, 30, false);
 #endif
 #ifdef HAVE_LANGEXTRA
    SETTING_INT("user_language",                &settings->user_language, true, RETRO_LANGUAGE_ENGLISH, false);

configuration.h

@@ -403,6 +403,7 @@ typedef struct settings
       unsigned check_frames;
       bool is_spectate;
       bool swap_input;
+      bool nat_traversal;
    } netplay;
 #endif
 

griffin/griffin.c

@@ -879,6 +879,7 @@ NETPLAY
 #include "../libretro-common/net/net_compat.c"
 #include "../libretro-common/net/net_socket.c"
 #include "../libretro-common/net/net_http.c"
+#include "../libretro-common/net/net_natt.c"
 #ifndef HAVE_SOCKET_LEGACY
 #include "../libretro-common/net/net_ifinfo.c"
 #endif

intl/msg_hash_us.c

@@ -1558,6 +1558,12 @@ int menu_hash_get_help_us_enum(enum msg_hash_enums msg, char *s, size_t len)
                "no checks. This value is only used on the \n"
                "netplay host. \n");
          break;
+      case MENU_ENUM_LABEL_NETPLAY_NAT_TRAVERSAL:
+         snprintf(s, len,
+               "When hosting, attempt to listen for\n"
+               "connections from the public internet, using\n"
+               "UPnP or similar technologies to escape LANs. \n");
+         break;
       case MENU_ENUM_LABEL_VIDEO_MAX_SWAPCHAIN_IMAGES:
          snprintf(s, len,
                "Maximum amount of swapchain images. This \n"

intl/msg_hash_us.h

@@ -22,6 +22,10 @@ MSG_HASH(
       MSG_GOT_CONNECTION_FROM,
       "Got connection from"
       )
+MSG_HASH(
+      MSG_PUBLIC_ADDRESS,
+      "Public address"
+      )
 MSG_HASH(
       MSG_NO_ARGUMENTS_SUPPLIED_AND_NO_MENU_BUILTIN,
       "No arguments supplied and no menu builtin, displaying help..."
@@ -922,6 +926,8 @@ MSG_HASH(MENU_ENUM_LABEL_VALUE_NETPLAY_SPECTATOR_MODE_ENABLE,
       "Netplay Spectator Enable")
 MSG_HASH(MENU_ENUM_LABEL_VALUE_NETPLAY_TCP_UDP_PORT,
       "Netplay TCP/UDP Port")
+MSG_HASH(MENU_ENUM_LABEL_VALUE_NETPLAY_NAT_TRAVERSAL,
+      "Netplay NAT Traversal")
 MSG_HASH(MENU_ENUM_LABEL_VALUE_NETWORK_CMD_ENABLE,
       "Network Commands")
 MSG_HASH(MENU_ENUM_LABEL_VALUE_NETWORK_CMD_PORT,

libretro-common/include/net/net_natt.h

@@ -0,0 +1,83 @@
+/* Copyright  (C) 2016 The RetroArch team
+ *
+ * ---------------------------------------------------------------------------------------
+ * The following license statement only applies to this file (net_natt.h).
+ * ---------------------------------------------------------------------------------------
+ *
+ * Permission is hereby granted, free of charge,
+ * to any person obtaining a copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+ * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef _LIBRETRO_SDK_NET_NATT_H
+#define _LIBRETRO_SDK_NET_NATT_H
+
+#include <net/net_compat.h>
+#include <net/net_socket.h>
+
+struct natt_status {
+   /** nfds for select when checking for input */
+   int nfds;
+
+   /** The fdset to be selected upon to check for responses */
+   fd_set fds;
+
+   /** True if there might be a request outstanding */
+   bool request_outstanding;
+
+   /** True if we've resolved an external IPv4 address */
+   bool have_inet4;
+
+   /** External IPv4 address */
+   struct sockaddr_in ext_inet4_addr;
+
+   /** True if we've resolved an external IPv6 address */
+   bool have_inet6;
+
+#ifdef AF_INET6
+   /** External IPv6 address */
+   struct sockaddr_in6 ext_inet6_addr;
+#endif
+
+   /** Internal status (currently unused) */
+   void *internal;
+};
+
+/**
+ * Initialize global NAT traversal structures (must be called once to use other
+ * functions) */
+void natt_init(void);
+
+/** Initialize a NAT traversal status object */
+bool natt_new(struct natt_status *status);
+
+/** Free a NAT traversal status object */
+void natt_free(struct natt_status *status);
+
+/**
+ * Make a port forwarding request. This may finish immediately or just send a
+ * request to the network. */
+bool natt_open_port(struct natt_status *status, struct sockaddr *addr,
+   socklen_t addrlen, enum socket_protocol proto);
+
+/**
+ * Make a port forwarding request when only the port is known. Forwards any
+ * address it can find. */
+bool natt_open_port_any(struct natt_status *status, uint16_t port,
+   enum socket_protocol proto);
+
+/** Check for port forwarding responses */
+bool natt_read(struct natt_status *status);
+
+#endif

libretro-common/net/net_natt.c

@@ -0,0 +1,221 @@
+/* Copyright  (C) 2016 The RetroArch team
+ *
+ * ---------------------------------------------------------------------------------------
+ * The following license statement only applies to this file (net_natt.c).
+ * ---------------------------------------------------------------------------------------
+ *
+ * Permission is hereby granted, free of charge,
+ * to any person obtaining a copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+ * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+
+#include <net/net_compat.h>
+#include <net/net_ifinfo.h>
+#include <retro_miscellaneous.h>
+
+#include <net/net_natt.h>
+
+#if HAVE_MINIUPNPC
+#include <miniupnpc/miniwget.h>
+#include <miniupnpc/miniupnpc.h>
+#include <miniupnpc/upnpcommands.h>
+
+static struct UPNPUrls urls;
+static struct IGDdatas data;
+#endif
+
+void natt_init(void)
+{
+#if HAVE_MINIUPNPC
+   struct UPNPDev * devlist;
+   struct UPNPDev * dev;
+   char * descXML;
+   int descXMLsize = 0;
+   int upnperror = 0;
+   memset(&urls, 0, sizeof(struct UPNPUrls));
+   memset(&data, 0, sizeof(struct IGDdatas));
+   devlist = upnpDiscover(2000, NULL, NULL, 0, 0, &upnperror);
+   if (devlist)
+   {
+      dev = devlist;
+      while (dev)
+      {
+         if (strstr (dev->st, "InternetGatewayDevice"))
+            break;
+         dev = dev->pNext;
+      }
+      if (!dev)
+         dev = devlist;
+
+      descXML = (char *) miniwget(dev->descURL, &descXMLsize, 0);
+      if (descXML)
+      {
+         parserootdesc (descXML, descXMLsize, &data);
+         free (descXML); descXML = 0;
+         GetUPNPUrls (&urls, &data, dev->descURL, 0);
+      }
+      freeUPNPDevlist(devlist);
+   }
+#endif
+}
+
+bool natt_new(struct natt_status *status)
+{
+   memset(status, 0, sizeof(struct natt_status));
+   return true;
+}
+
+void natt_free(struct natt_status *status)
+{
+   /* Nothing */
+}
+
+bool natt_open_port(struct natt_status *status, struct sockaddr *addr, socklen_t addrlen, enum socket_protocol proto)
+{
+#if HAVE_MINIUPNPC
+   char host[PATH_MAX_LENGTH], ext_host[PATH_MAX_LENGTH],
+        port_str[6], ext_port_str[6];
+   const char *proto_str;
+   struct addrinfo hints = {0}, *ext_addrinfo;
+   int r;
+
+   /* if NAT traversal is uninitialized or unavailable, oh well */
+   if (!urls.controlURL[0])
+      return false;
+
+   /* figure out the internal info */
+   if (getnameinfo(addr, addrlen, host, PATH_MAX_LENGTH, port_str, 6, NI_NUMERICHOST|NI_NUMERICSERV) != 0)
+      return false;
+   proto_str = (proto == SOCKET_PROTOCOL_UDP) ? "UDP" : "TCP";
+
+   /* add the port mapping */
+   r = UPNP_AddAnyPortMapping(urls.controlURL, data.first.servicetype, port_str,
+      port_str, host, "retroarch", proto_str, NULL, "3600", ext_port_str);
+   if (r == 501 /* Action Failed */)
+   {
+      /* try the older AddPortMapping */
+      memcpy(ext_port_str, port_str, 6);
+      r = UPNP_AddPortMapping(urls.controlURL, data.first.servicetype, port_str,
+         port_str, host, "retroarch", proto_str, NULL, "3600");
+   }
+   if (r != 0)
+      return false;
+
+   /* get the external IP */
+   r = UPNP_GetExternalIPAddress(urls.controlURL, data.first.servicetype, ext_host);
+   if (r != 0)
+      return false;
+
+   /* update the status */
+   if (getaddrinfo_retro(ext_host, ext_port_str, &hints, &ext_addrinfo) != 0)
+      return false;
+
+   if (ext_addrinfo->ai_family == AF_INET &&
+       ext_addrinfo->ai_addrlen >= sizeof(struct sockaddr_in))
+   {
+      status->have_inet4 = true;
+      status->ext_inet4_addr = *((struct sockaddr_in *) ext_addrinfo->ai_addr);
+   }
+#ifdef AF_INET6
+   else if (ext_addrinfo->ai_family == AF_INET6 &&
+            ext_addrinfo->ai_addrlen >= sizeof(struct sockaddr_in6))
+   {
+      status->have_inet6 = true;
+      status->ext_inet6_addr = *((struct sockaddr_in6 *) ext_addrinfo->ai_addr);
+   }
+   else
+   {
+      freeaddrinfo_retro(ext_addrinfo);
+      return false;
+   }
+#endif
+
+   return true;
+
+#else
+   return false;
+#endif
+}
+
+bool natt_open_port_any(struct natt_status *status, uint16_t port, enum socket_protocol proto)
+{
+   struct net_ifinfo *list;
+   bool ret = false;
+   size_t i;
+   struct addrinfo hints = {0}, *addr;
+   char port_str[6];
+
+   sprintf(port_str, "%hu", port);
+
+   /* get our interfaces */
+   if ((list = (struct net_ifinfo *) calloc(1, sizeof(struct net_ifinfo))) == NULL)
+       return false;
+   if (!net_ifinfo_new(list))
+   {
+      free(list);
+      return false;
+   }
+
+   /* loop through them */
+   for (i = 0; i < list->size; i++)
+   {
+      struct net_ifinfo_entry *entry = list->entries + i;
+
+      /* ignore localhost */
+      if (!strcmp(entry->host, "127.0.0.1") || !strcmp(entry->host, "::1"))
+         continue;
+
+      /* make a request for this host */
+      if (getaddrinfo_retro(entry->host, port_str, &hints, &addr) == 0)
+      {
+         ret = natt_open_port(status, addr->ai_addr, addr->ai_addrlen, proto) || ret;
+         freeaddrinfo_retro(addr);
+      }
+   }
+
+   /* This really shouldn't free list, but does */
+   net_ifinfo_free(list);
+
+   return ret;
+}
+
+bool natt_read(struct natt_status *status)
+{
+   /* MiniUPNPC is always synchronous, so there's nothing to read here.
+    * Reserved for future backends. */
+   return false;
+}
+
+#if 0
+/* If we want to remove redirects in the future, this is a sample of how to do
+ * that */
+void upnp_rem_redir (int port)
+{
+   char port_str[16];
+   int t;
+   printf("TB : upnp_rem_redir (%d)\n", port);
+   if(urls.controlURL[0] == '\0')
+   {
+      printf("TB : the init was not done !\n");
+      return;
+   }
+   sprintf(port_str, "%d", port);
+   UPNP_DeletePortMapping(urls.controlURL, data.first.servicetype, port_str, "TCP", NULL);
+}
+#endif

menu/menu_displaylist.c

@@ -4942,6 +4942,10 @@ bool menu_displaylist_ctl(enum menu_displaylist_ctl_state type, void *data)
                   MENU_ENUM_LABEL_NETPLAY_CLIENT_SWAP_INPUT,
                   PARSE_ONLY_BOOL, false) != -1)
                count++;
+            if (menu_displaylist_parse_settings_enum(menu, info,
+                  MENU_ENUM_LABEL_NETPLAY_NAT_TRAVERSAL,
+                  PARSE_ONLY_BOOL, false) != -1)
+               count++;
             if (menu_displaylist_parse_settings_enum(menu, info,
                   MENU_ENUM_LABEL_NETWORK_CMD_ENABLE,
                   PARSE_ONLY_BOOL, false) != -1)

menu/menu_setting.c

@@ -5589,6 +5589,21 @@ static bool setting_append_list(
                   general_read_handler,
                   SD_FLAG_NONE);
 
+            CONFIG_BOOL(
+                  list, list_info,
+                  &settings->netplay.is_spectate,
+                  MENU_ENUM_LABEL_NETPLAY_NAT_TRAVERSAL,
+                  MENU_ENUM_LABEL_VALUE_NETPLAY_NAT_TRAVERSAL,
+                  false,
+                  MENU_ENUM_LABEL_VALUE_OFF,
+                  MENU_ENUM_LABEL_VALUE_ON,
+                  &group_info,
+                  &subgroup_info,
+                  parent_group,
+                  general_write_handler,
+                  general_read_handler,
+                  SD_FLAG_NONE);
+
             CONFIG_BOOL(
                   list, list_info,
                   &settings->netplay.swap_input,

msg_hash.h

@@ -173,6 +173,7 @@ enum msg_hash_enums
    MSG_NO_STATE_HAS_BEEN_LOADED_YET,
    MSG_GOT_CONNECTION_FROM,
    MSG_CONNECTION_SLOT,
+   MSG_PUBLIC_ADDRESS,
    MSG_NO_SAVE_STATE_HAS_BEEN_OVERWRITTEN_YET,
    MSG_CANNOT_INFER_NEW_CONFIG_PATH,
    MSG_UNDID_LOAD_STATE,
@@ -975,6 +976,7 @@ enum msg_hash_enums
    MENU_LABEL(NETPLAY_CHECK_FRAMES),
    MENU_LABEL(NETPLAY_SPECTATOR_MODE_ENABLE),
    MENU_LABEL(NETPLAY_TCP_UDP_PORT),
+   MENU_LABEL(NETPLAY_NAT_TRAVERSAL),
    MENU_LABEL(SORT_SAVEFILES_ENABLE),
    MENU_LABEL(SORT_SAVESTATES_ENABLE),
    MENU_LABEL(NETPLAY_IP_ADDRESS),

network/netplay/netplay.c

@@ -63,6 +63,8 @@ static netplay_t *netplay_data = NULL;
 /* Used to avoid recursive netplay calls */
 static bool in_netplay = false;
 
+static void announce_nat_traversal(netplay_t *netplay);
+
 static int init_tcp_connection(const struct addrinfo *res,
       bool server, bool spectate,
       struct sockaddr *other_addr, socklen_t addr_size)
@@ -186,6 +188,22 @@ static bool init_tcp_socket(netplay_t *netplay, const char *server,
    return ret;
 }
 
+static void init_nat_traversal(netplay_t *netplay)
+{
+   natt_init();
+
+   if (!natt_new(&netplay->nat_traversal_state))
+   {
+      netplay->nat_traversal = false;
+      return;
+   }
+
+   natt_open_port_any(&netplay->nat_traversal_state, netplay->tcp_port, SOCKET_PROTOCOL_TCP);
+
+   if (!netplay->nat_traversal_state.request_outstanding)
+      announce_nat_traversal(netplay);
+}
+
 static bool init_ad_socket(netplay_t *netplay, uint16_t port)
 {
    int fd = socket_init((void**)&netplay->addr, port, NULL, SOCKET_TYPE_DATAGRAM);
@@ -216,6 +234,9 @@ static bool init_socket(netplay_t *netplay, const char *server, uint16_t port)
    if (!init_tcp_socket(netplay, server, port, netplay->spectate.enabled))
       return false;
 
+   if (netplay->is_server && netplay->nat_traversal)
+      init_nat_traversal(netplay);
+
    return true;
 }
 
@@ -1061,6 +1082,36 @@ void netplay_log_connection(const struct sockaddr_storage *their_addr,
 
 #endif
 
+static void announce_nat_traversal(netplay_t *netplay)
+{
+   char msg[512], host[PATH_MAX_LENGTH], port[6];
+
+   if (netplay->nat_traversal_state.have_inet4)
+   {
+      if (getnameinfo((const struct sockaddr *) &netplay->nat_traversal_state.ext_inet4_addr,
+         sizeof(struct sockaddr_in),
+         host, PATH_MAX_LENGTH, port, 6, NI_NUMERICHOST|NI_NUMERICSERV) != 0)
+         return;
+
+   }
+#ifdef AF_INET6
+   else if (netplay->nat_traversal_state.have_inet6)
+   {
+      if (getnameinfo((const struct sockaddr *) &netplay->nat_traversal_state.ext_inet6_addr,
+         sizeof(struct sockaddr_in6),
+         host, PATH_MAX_LENGTH, port, 6, NI_NUMERICHOST|NI_NUMERICSERV) != 0)
+         return;
+
+   }
+#endif
+   else return;
+
+   snprintf(msg, sizeof(msg), "%s: %s:%s\n",
+         msg_hash_to_str(MSG_PUBLIC_ADDRESS),
+         host, port);
+   runloop_msg_queue_push(msg, 1, 180, false);
+   RARCH_LOG("%s\n", msg);
+}
 
 
 bool netplay_try_init_serialization(netplay_t *netplay)
@@ -1180,6 +1231,7 @@ static bool netplay_init_buffers(netplay_t *netplay, unsigned frames)
  * @check_frames         : Frequency with which to check CRCs.
  * @cb                   : Libretro callbacks.
  * @spectate             : If true, enable spectator mode.
+ * @nat_traversal        : If true, attempt NAT traversal.
  * @nick                 : Nickname of user.
  * @quirks               : Netplay quirks required for this session.
  *
@@ -1188,10 +1240,9 @@ static bool netplay_init_buffers(netplay_t *netplay, unsigned frames)
  *
  * Returns: new netplay handle.
  **/
-netplay_t *netplay_new(const char *server, uint16_t port,
+netplay_t *netplay_new(const char *server, uint16_t port, unsigned frames,
-      unsigned frames, unsigned check_frames,
+      unsigned check_frames, const struct retro_callbacks *cb, bool spectate,
-      const struct retro_callbacks *cb,
+      bool nat_traversal, const char *nick, uint64_t quirks)
-      bool spectate, const char *nick, uint64_t quirks)
 {
    netplay_t *netplay = (netplay_t*)calloc(1, sizeof(*netplay));
    if (!netplay)
@@ -1203,6 +1254,7 @@ netplay_t *netplay_new(const char *server, uint16_t port,
    netplay->port              = server ? 0 : 1;
    netplay->spectate.enabled  = spectate;
    netplay->is_server         = server == NULL;
+   netplay->nat_traversal     = netplay->is_server ? nat_traversal : false;
    netplay->stall_frames      = frames;
    netplay->check_frames      = check_frames;
    netplay->quirks            = quirks;
@@ -1338,6 +1390,9 @@ void netplay_free(netplay_t *netplay)
       free(netplay->spectate.input);
    }
 
+   if (netplay->nat_traversal)
+      natt_free(&netplay->nat_traversal_state);
+
    if (netplay->buffer)
    {
       for (i = 0; i < netplay->buffer_size; i++)
@@ -1383,11 +1438,26 @@ bool netplay_pre_frame(netplay_t *netplay)
       netplay_try_init_serialization(netplay);
    }
 
-   /* Advertise our server if applicable */
    if (netplay->is_server)
    {
+      /* Advertise our server if applicable */
       if (netplay_ad_fd >= 0 || init_ad_socket(netplay, RARCH_DEFAULT_PORT))
          netplay_ad_server(netplay, netplay_ad_fd);
+
+      /* NAT traversal if applicable */
+      if (netplay->nat_traversal &&
+          netplay->nat_traversal_state.request_outstanding &&
+          !netplay->nat_traversal_state.have_inet4)
+      {
+         struct timeval tmptv = {0};
+         fd_set fds = netplay->nat_traversal_state.fds;
+         if (socket_select(netplay->nat_traversal_state.nfds, &fds, NULL, NULL, &tmptv) > 0)
+            natt_read(&netplay->nat_traversal_state);
+
+         if (!netplay->nat_traversal_state.request_outstanding ||
+             netplay->nat_traversal_state.have_inet4)
+            announce_nat_traversal(netplay);
+      }
    }
 
    if (!netplay->net_cbs->pre_frame(netplay))
@@ -1613,7 +1683,8 @@ bool init_netplay(bool is_spectate, const char *server, unsigned port)
          netplay_is_client ? server : NULL,
          port ? port : RARCH_DEFAULT_PORT,
          settings->netplay.sync_frames, settings->netplay.check_frames, &cbs,
-         is_spectate, settings->username, quirks);
+         is_spectate, settings->netplay.nat_traversal, settings->username,
+         quirks);
 
    if (netplay_data)
       return true;

network/netplay/netplay.h

@@ -137,6 +137,7 @@ size_t audio_sample_batch_net(const int16_t *data, size_t frames);
  * @check_frames         : Frequency with which to check CRCs.
  * @cb                   : Libretro callbacks.
  * @spectate             : If true, enable spectator mode.
+ * @nat_traversal        : If true, attempt NAT traversal.
  * @nick                 : Nickname of user.
  * @quirks               : Netplay quirks.
  *
@@ -147,7 +148,7 @@ size_t audio_sample_batch_net(const int16_t *data, size_t frames);
  **/
 netplay_t *netplay_new(const char *server,
       uint16_t port, unsigned frames, unsigned check_frames,
-      const struct retro_callbacks *cb, bool spectate,
+      const struct retro_callbacks *cb, bool spectate, bool nat_traversal,
       const char *nick, uint64_t quirks);
 
 /**

network/netplay/netplay_net.c

@@ -20,6 +20,7 @@
 
 #include <net/net_compat.h>
 #include <net/net_socket.h>
+#include <net/net_natt.h>
 
 #include "netplay_private.h"
 
@@ -337,6 +338,19 @@ static bool netplay_net_info_cb(netplay_t* netplay, unsigned frames)
       netplay->has_connection = true;
    }
 
+   {
+      struct natt_status status;
+      natt_init();
+      if (natt_new(&status) && natt_open_port_any(&status, netplay->tcp_port, SOCKET_PROTOCOL_TCP))
+      {
+         fprintf(stderr, "Forwarded to %d!\n", status.ext_inet4_addr.sin_port);
+      }
+      else
+      {
+         fprintf(stderr, "Forwarding failed :(\n");
+      }
+   }
+
    return true;
 }
 

network/netplay/netplay_private.h

@@ -20,6 +20,7 @@
 #include "netplay.h"
 
 #include <net/net_compat.h>
+#include <net/net_natt.h>
 #include <features/features_cpu.h>
 #include <streams/trans_stream.h>
 #include <retro_endianness.h>
@@ -124,6 +125,9 @@ struct netplay
    int fd;
    /* TCP port (if serving) */
    uint16_t tcp_port;
+   /* NAT traversal info (if NAT traversal is used and serving) */
+   bool nat_traversal;
+   struct natt_status nat_traversal_state;
    /* Which port is governed by netplay (other user)? */
    unsigned port;
    bool has_connection;

qb/config.libs.sh

@@ -182,6 +182,10 @@ if [ "$HAVE_NETWORKING" = 'yes' ]; then
    fi
    HAVE_NETWORK_CMD=yes
    HAVE_NETWORKGAMEPAD=yes
+
+   if [ "$HAVE_MINIUPNPC" != "no" ]; then
+      check_lib MINIUPNPC "-lminiupnpc"
+   fi
 else
    echo "Warning: All networking features have been disabled."
    HAVE_NETWORK_CMD='no'

qb/config.params.sh

@@ -28,6 +28,7 @@ HAVE_DYLIB=auto            # Dynamic loading support
 HAVE_NETWORKING=auto       # Networking features (recommended)
 HAVE_NETWORKGAMEPAD=auto   # Networked game pad (plus baked-in core)
 C89_NETWORKGAMEPAD=no
+HAVE_MINIUPNPC=auto        # Mini UPnP client library (for NAT traversal)
 HAVE_D3D9=yes              # Direct3D 9 support
 HAVE_OPENGL=auto           # OpenGL support
 HAVE_MALI_FBDEV=no         # Mali fbdev context support