Lift NetXCmd limits

Sudden spark in my brain that solves a pretty obnoxious issue in netcode. What it does is that it buffers any NetXCmd that doesn't fit the NetXCmd buffer, and sends it in any following tic instead. This will delay it for a tic or more, but that's better than just dropping it entirely, causing all kinds of issues for players.

Personally, I'd just want to get rid of NetXCmd entirely, since the way it's implemented is a nightmare from a maintenance standpoint and has serious privacy and security issues, not to mention that it's benefits aren't even significant anymore. It might've made a difference back in the early 2000s or before that, but it certainly doesn't make a difference now.

src/netcode/net_command.c

@@ -21,6 +21,16 @@
 #include "../z_zone.h"
 #include "../doomtype.h"
 
+typedef struct textcmdbuf_s textcmdbuf_t;
+
+struct textcmdbuf_s
+{
+	textcmdbuf_t *next;
+	UINT8 cmd[MAXTEXTCMD];
+};
+
+static textcmdbuf_t *textcmdbuf;
+static textcmdbuf_t *textcmdbuf2;
 textcmdtic_t *textcmds[TEXTCMD_HASH_SIZE] = {NULL};
 UINT8 localtextcmd[MAXTEXTCMD];
 UINT8 localtextcmd2[MAXTEXTCMD]; // splitscreen
@@ -37,21 +47,57 @@ void RegisterNetXCmd(netxcmd_t id, void (*cmd_f)(UINT8 **p, INT32 playernum))
 	listnetxcmd[id] = cmd_f;
 }
 
+static void WriteNetXCmd(UINT8 *cmd, netxcmd_t id, const void *param, size_t nparam)
+{
+	cmd[0]++;
+	cmd[cmd[0]] = (UINT8)id;
+	if (param && nparam)
+	{
+		M_Memcpy(&cmd[cmd[0]+1], param, nparam);
+		cmd[0] = (UINT8)(cmd[0] + (UINT8)nparam);
+	}
+}
+
 void SendNetXCmd(netxcmd_t id, const void *param, size_t nparam)
 {
 	if (localtextcmd[0]+2+nparam > MAXTEXTCMD)
 	{
+		textcmdbuf_t *buf = textcmdbuf;
+
+		if (2+nparam > MAXTEXTCMD)
+		{
+			CONS_Alert(CONS_ERROR, M_GetText("packet too large to fit NetXCmd, cannot add netcmd %d! (size: %s, max: %d)\n"), id, sizeu1(2+nparam), MAXTEXTCMD);
+			return;
+		}
+
 		// for future reference: if (cv_debug) != debug disabled.
-		CONS_Alert(CONS_ERROR, M_GetText("NetXCmd buffer full, cannot add netcmd %d! (size: %d, needed: %s)\n"), id, localtextcmd[0], sizeu1(nparam));
+		CONS_Alert(CONS_NOTICE, M_GetText("NetXCmd buffer full, delaying netcmd %d... (size: %d, needed: %s)\n"), id, localtextcmd[0], sizeu1(nparam));
+		if (buf == NULL)
+		{
+			textcmdbuf = Z_Malloc(sizeof(textcmdbuf_t), PU_STATIC, NULL);
+			textcmdbuf->cmd[0] = 0;
+			textcmdbuf->next = NULL;
+			WriteNetXCmd(textcmdbuf->cmd, id, param, nparam);
+			return;
+		}
+
+		while (buf->next != NULL)
+			buf = buf->next;
+
+		if (buf->cmd[0]+2+nparam > MAXTEXTCMD)
+		{
+			buf->next = Z_Malloc(sizeof(textcmdbuf_t), PU_STATIC, NULL);
+			buf->next->cmd[0] = 0;
+			buf->next->next = NULL;
+			WriteNetXCmd(buf->next->cmd, id, param, nparam);
+		}
+		else
+		{
+			WriteNetXCmd(buf->cmd, id, param, nparam);
+		}
 		return;
 	}
-	localtextcmd[0]++;
-	localtextcmd[localtextcmd[0]] = (UINT8)id;
-	if (param && nparam)
-	{
-		M_Memcpy(&localtextcmd[localtextcmd[0]+1], param, nparam);
-		localtextcmd[0] = (UINT8)(localtextcmd[0] + (UINT8)nparam);
-	}
+	WriteNetXCmd(localtextcmd, id, param, nparam);
 }
 
 // splitscreen player
@@ -59,16 +105,42 @@ void SendNetXCmd2(netxcmd_t id, const void *param, size_t nparam)
 {
 	if (localtextcmd2[0]+2+nparam > MAXTEXTCMD)
 	{
-		I_Error("No more place in the buffer for netcmd %d\n",id);
+		textcmdbuf_t *buf = textcmdbuf2;
+
+		if (2+nparam > MAXTEXTCMD)
+		{
+			CONS_Alert(CONS_ERROR, M_GetText("packet too large to fit NetXCmd, cannot add netcmd %d! (size: %s, max: %d)\n"), id, sizeu1(2+nparam), MAXTEXTCMD);
+			return;
+		}
+
+		// for future reference: if (cv_debug) != debug disabled.
+		CONS_Alert(CONS_NOTICE, M_GetText("NetXCmd buffer full, delaying netcmd %d... (size: %d, needed: %s)\n"), id, localtextcmd2[0], sizeu1(nparam));
+		if (buf == NULL)
+		{
+			textcmdbuf2 = Z_Malloc(sizeof(textcmdbuf_t), PU_STATIC, NULL);
+			textcmdbuf2->cmd[0] = 0;
+			textcmdbuf2->next = NULL;
+			WriteNetXCmd(textcmdbuf2->cmd, id, param, nparam);
+			return;
+		}
+
+		while (buf->next != NULL)
+			buf = buf->next;
+
+		if (buf->cmd[0]+2+nparam > MAXTEXTCMD)
+		{
+			buf->next = Z_Malloc(sizeof(textcmdbuf_t), PU_STATIC, NULL);
+			buf->next->cmd[0] = 0;
+			buf->next->next = NULL;
+			WriteNetXCmd(buf->next->cmd, id, param, nparam);
+		}
+		else
+		{
+			WriteNetXCmd(buf->cmd, id, param, nparam);
+		}
 		return;
 	}
-	localtextcmd2[0]++;
-	localtextcmd2[localtextcmd2[0]] = (UINT8)id;
-	if (param && nparam)
-	{
-		M_Memcpy(&localtextcmd2[localtextcmd2[0]+1], param, nparam);
-		localtextcmd2[0] = (UINT8)(localtextcmd2[0] + (UINT8)nparam);
-	}
+	WriteNetXCmd(localtextcmd2, id, param, nparam);
 }
 
 UINT8 GetFreeXCmdSize(void)
@@ -345,7 +417,16 @@ void CL_SendNetCommands(void)
 		M_Memcpy(netbuffer->u.textcmd,localtextcmd, localtextcmd[0]+1);
 		// All extra data have been sent
 		if (HSendPacket(servernode, true, 0, localtextcmd[0]+1)) // Send can fail...
+		{
 			localtextcmd[0] = 0;
+			if (textcmdbuf != NULL)
+			{
+				textcmdbuf_t *buf = textcmdbuf;
+				M_Memcpy(localtextcmd, textcmdbuf->cmd, textcmdbuf->cmd[0]+1);
+				textcmdbuf = textcmdbuf->next;
+				Z_Free(buf);
+			}
+		}
 	}
 
 	// Send extra data if needed for player 2 (splitscreen)
@@ -355,7 +436,16 @@ void CL_SendNetCommands(void)
 		M_Memcpy(netbuffer->u.textcmd, localtextcmd2, localtextcmd2[0]+1);
 		// All extra data have been sent
 		if (HSendPacket(servernode, true, 0, localtextcmd2[0]+1)) // Send can fail...
+		{
 			localtextcmd2[0] = 0;
+			if (textcmdbuf2 != NULL)
+			{
+				textcmdbuf_t *buf = textcmdbuf2;
+				M_Memcpy(localtextcmd2, textcmdbuf2->cmd, textcmdbuf2->cmd[0]+1);
+				textcmdbuf2 = textcmdbuf2->next;
+				Z_Free(buf);
+			}
+		}
 	}
 }