NAT traversal

Adding NAT traveral interface to libretro-common, with (currently) a
backend support MiniUPNPC. Sensible future backends would be libupnp and
a direct implementation of PCP/NAT-PMP.

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)),)

libretro-common/include/net/net_natt.h

@@ -0,0 +1,47 @@
+#include <net/net_compat.h>
+
+struct natt_status {
+    /** The fdset to be selected upon to check for responses */
+    fd_set fds;
+
+    /** 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);
+
+/**
+ * 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);
+
+/** Check for port forwarding responses */
+bool natt_read(struct natt_status *status);

libretro-common/net/net_natt.c

@@ -0,0 +1,192 @@
+#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 = 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)
+{
+#if HAVE_MINIUPNPC
+   char host[PATH_MAX_LENGTH], ext_host[PATH_MAX_LENGTH],
+        port_str[6], ext_port_str[6];
+   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, 0) != 0)
+      return false;
+
+   /* add the port mapping */
+   r = UPNP_AddAnyPortMapping(urls.controlURL, data.first.servicetype, port_str,
+      port_str, host, "retroarch", "TCP", 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", "TCP", NULL, "3600");
+   }
+   fprintf(stderr, "ERROR: %d\n", r);
+   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)
+{
+   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 (!net_ifinfo_new(&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) || ret;
+         freeaddrinfo_retro(addr);
+      }
+   }
+
+   /* BUGS! 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

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