From e2621a84742aebee5bd80afe7efebdeadc6403b4 Mon Sep 17 00:00:00 2001
From: Bernhard Schelling <14200249+schellingb@users.noreply.github.com>
Date: Sat, 24 Jun 2023 02:46:50 +0900
Subject: [PATCH] Add enum netplay_modus

---
 network/netplay/netplay_private.h | 16 ++++++++++++++++
 retroarch.c                       |  4 ++++
 runloop.c                         | 10 ++++++++--
 3 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/network/netplay/netplay_private.h b/network/netplay/netplay_private.h
index 05257b77bf..2e7a6744a9 100644
--- a/network/netplay/netplay_private.h
+++ b/network/netplay/netplay_private.h
@@ -268,6 +268,19 @@ enum rarch_netplay_stall_reason
    NETPLAY_STALL_SERVER_REQUESTED
 };
 
+enum netplay_modus
+{
+   /* Netplay operates by having all participants send input data every
+      frame and run cores deterministically in sync on all connected devices.
+      It will rewind frames when input data from the past arrives. */
+   NETPLAY_MODUS_INPUT_FRAME_SYNC = 0,
+
+   /* Netplay operates by having the active core send and receive custom
+      packets once connection setup and handshake has been completed.
+      Time skips (pausing, fast forward, save state loading) are refused. */
+	NETPLAY_MODUS_CORE_PACKET_INTERFACE = 1,
+};
+
 /* Input state for a particular client-device pair */
 typedef struct netplay_input_state
 {
@@ -607,6 +620,9 @@ struct netplay
    /* Are we stalled? */
    enum rarch_netplay_stall_reason stall;
 
+   /* Netplay mode of operation (cannot change at runtime) */
+   enum netplay_modus modus;
+
    /* Keyboard mapping (network and host) */
    uint16_t mapping_hton[RETROK_LAST];
    uint16_t mapping_ntoh[NETPLAY_KEY_LAST];
diff --git a/retroarch.c b/retroarch.c
index 723d9ff856..025085ad1f 100644
--- a/retroarch.c
+++ b/retroarch.c
@@ -2915,6 +2915,10 @@ bool command_event(enum event_command cmd, void *data)
 #ifdef HAVE_CHEEVOS
             if (rcheevos_hardcore_active())
                return false;
+#endif
+#ifdef HAVE_NETWORKING
+            if (!netplay_driver_ctl(RARCH_NETPLAY_CTL_ALLOW_TIMESKIP, NULL))
+               return false;
 #endif
             if (rewind_enable)
             {
diff --git a/runloop.c b/runloop.c
index 62813f6753..8f2e14c2a7 100644
--- a/runloop.c
+++ b/runloop.c
@@ -3487,9 +3487,15 @@ bool runloop_environment_cb(unsigned cmd, void *data)
       case RETRO_ENVIRONMENT_SET_NETPACKET_INTERFACE:
 #ifdef HAVE_NETWORKING
          RARCH_LOG("[Environ]: RETRO_ENVIRONMENT_SET_NETPACKET_INTERFACE.\n");
-         netplay_driver_ctl(RARCH_NETPLAY_CTL_SET_CORE_PACKET_INTERFACE, data);
-#endif
+         if (!netplay_driver_ctl(RARCH_NETPLAY_CTL_SET_CORE_PACKET_INTERFACE, data))
+         {
+            RARCH_ERR("[Environ] RETRO_ENVIRONMENT_SET_NETPACKET_INTERFACE set too late\n");
+            return false;
+         }
          break;
+#else
+         return false;
+#endif
 
       default:
          RARCH_LOG("[Environ]: UNSUPPORTED (#%u).\n", cmd);