From 061fd4761a0c752c56163ee039c31c646b811c7a Mon Sep 17 00:00:00 2001
From: Louis-Antoine <lamr@free.fr>
Date: Tue, 12 May 2020 19:06:40 +0200
Subject: [PATCH 01/12] Rename some file transfer functions

---
 src/d_clisrv.c | 16 ++++++++--------
 src/d_netfil.c | 49 +++++++++++++++++++++++++------------------------
 src/d_netfil.h | 14 +++++++-------
 src/i_tcp.c    |  2 +-
 4 files changed, 41 insertions(+), 40 deletions(-)

diff --git a/src/d_clisrv.c b/src/d_clisrv.c
index 43321d92d..a0a554609 100644
--- a/src/d_clisrv.c
+++ b/src/d_clisrv.c
@@ -1598,7 +1598,7 @@ static void SV_SendSaveGame(INT32 node)
 		WRITEUINT32(savebuffer, 0);
 	}
 
-	SV_SendRam(node, buffertosend, length, SF_RAM, 0);
+	AddRamToSendQueue(node, buffertosend, length, SF_RAM, 0);
 	save_p = NULL;
 
 	// Remember when we started sending the savegame so we can handle timeouts
@@ -1978,7 +1978,7 @@ static boolean CL_ServerConnectionSearchTicker(boolean viams, tic_t *asksent)
 					return false;
 				}
 				// no problem if can't send packet, we will retry later
-				if (CL_SendRequestFile())
+				if (CL_SendFileRequest())
 					cl_mode = CL_DOWNLOADFILES;
 			}
 		}
@@ -2106,7 +2106,7 @@ static boolean CL_ServerConnectionTicker(boolean viams, const char *tmpsave, tic
 		// why are these here? this is for servers, we're a client
 		//if (key == 's' && server)
 		//	doomcom->numnodes = (INT16)pnumnodes;
-		//SV_FileSendTicker();
+		//FileSendTicker();
 		*oldtic = I_GetTime();
 
 #ifdef CLIENT_LOADINGSCREEN
@@ -3911,13 +3911,13 @@ static void HandlePacketFromAwayNode(SINT8 node)
 				break;
 			}
 			SERVERONLY
-			Got_Filetxpak();
+			PT_FileFragment();
 			break;
 
 		case PT_REQUESTFILE:
 			if (server)
 			{
-				if (!cv_downloading.value || !Got_RequestFilePak(node))
+				if (!cv_downloading.value || !PT_RequestFile(node))
 					Net_CloseConnection(node); // close connection if one of the requested files could not be sent, or you disabled downloading anyway
 			}
 			else
@@ -4216,7 +4216,7 @@ static void HandlePacketFromPlayer(SINT8 node)
 			{
 				char *name = va("%s" PATHSEP "%s", luafiledir, luafiletransfers->filename);
 				boolean textmode = !strchr(luafiletransfers->mode, 'b');
-				SV_SendLuaFile(node, name, textmode);
+				AddLuaFileToSendQueue(node, name, textmode);
 			}
 			break;
 		case PT_HASLUAFILE:
@@ -4348,7 +4348,7 @@ static void HandlePacketFromPlayer(SINT8 node)
 				break;
 			}
 			if (client)
-				Got_Filetxpak();
+				PT_FileFragment();
 			break;
 		case PT_SENDINGLUAFILE:
 			if (client)
@@ -5073,7 +5073,7 @@ void NetUpdate(void)
 		CON_Ticker();
 	}
 
-	SV_FileSendTicker();
+	FileSendTicker();
 }
 
 /** Returns the number of players playing.
diff --git a/src/d_netfil.c b/src/d_netfil.c
index 6d3ac7f9d..ec0a9b66c 100644
--- a/src/d_netfil.c
+++ b/src/d_netfil.c
@@ -56,7 +56,7 @@
 #include <errno.h>
 
 // Prototypes
-static boolean SV_SendFile(INT32 node, const char *filename, UINT8 fileid);
+static boolean AddFileToSendQueue(INT32 node, const char *filename, UINT8 fileid);
 
 // Sender structure
 typedef struct filetx_s
@@ -253,7 +253,7 @@ boolean CL_CheckDownloadable(void)
   * \note Sends a PT_REQUESTFILE packet
   *
   */
-boolean CL_SendRequestFile(void)
+boolean CL_SendFileRequest(void)
 {
 	char *p;
 	INT32 i;
@@ -298,7 +298,7 @@ boolean CL_SendRequestFile(void)
 
 // get request filepak and put it on the send queue
 // returns false if a requested file was not found or cannot be sent
-boolean Got_RequestFilePak(INT32 node)
+boolean PT_RequestFile(INT32 node)
 {
 	char wad[MAX_WADPATH+1];
 	UINT8 *p = netbuffer->u.textcmd;
@@ -309,7 +309,7 @@ boolean Got_RequestFilePak(INT32 node)
 		if (id == 0xFF)
 			break;
 		READSTRINGN(p, wad, MAX_WADPATH);
-		if (!SV_SendFile(node, wad, id))
+		if (!AddFileToSendQueue(node, wad, id))
 		{
 			SV_AbortSendFiles(node);
 			return false; // don't read the rest of the files
@@ -621,11 +621,11 @@ static INT32 filestosend = 0;
   * \param node The node to send the file to
   * \param filename The file to send
   * \param fileid ???
-  * \sa SV_SendRam
-  * \sa SV_SendLuaFile
+  * \sa AddRamToSendQueue
+  * \sa AddLuaFileToSendQueue
   *
   */
-static boolean SV_SendFile(INT32 node, const char *filename, UINT8 fileid)
+static boolean AddFileToSendQueue(INT32 node, const char *filename, UINT8 fileid)
 {
 	filetx_t **q; // A pointer to the "next" field of the last file in the list
 	filetx_t *p; // The new file request
@@ -643,7 +643,7 @@ static boolean SV_SendFile(INT32 node, const char *filename, UINT8 fileid)
 	// Allocate a file request and append it to the file list
 	p = *q = (filetx_t *)malloc(sizeof (filetx_t));
 	if (!p)
-		I_Error("SV_SendFile: No more memory\n");
+		I_Error("AddFileToSendQueue: No more memory\n");
 
 	// Initialise with zeros
 	memset(p, 0, sizeof (filetx_t));
@@ -651,7 +651,7 @@ static boolean SV_SendFile(INT32 node, const char *filename, UINT8 fileid)
 	// Allocate the file name
 	p->id.filename = (char *)malloc(MAX_WADPATH);
 	if (!p->id.filename)
-		I_Error("SV_SendFile: No more memory\n");
+		I_Error("AddFileToSendQueue: No more memory\n");
 
 	// Set the file name and get rid of the path
 	strlcpy(p->id.filename, filename, MAX_WADPATH);
@@ -712,11 +712,11 @@ static boolean SV_SendFile(INT32 node, const char *filename, UINT8 fileid)
   * \param size The size of the block in bytes
   * \param freemethod How to free the block after it has been sent
   * \param fileid ???
-  * \sa SV_SendFile
-  * \sa SV_SendLuaFile
+  * \sa AddFileToSendQueue
+  * \sa AddLuaFileToSendQueue
   *
   */
-void SV_SendRam(INT32 node, void *data, size_t size, freemethod_t freemethod, UINT8 fileid)
+void AddRamToSendQueue(INT32 node, void *data, size_t size, freemethod_t freemethod, UINT8 fileid)
 {
 	filetx_t **q; // A pointer to the "next" field of the last file in the list
 	filetx_t *p; // The new file request
@@ -729,7 +729,7 @@ void SV_SendRam(INT32 node, void *data, size_t size, freemethod_t freemethod, UI
 	// Allocate a file request and append it to the file list
 	p = *q = (filetx_t *)malloc(sizeof (filetx_t));
 	if (!p)
-		I_Error("SV_SendRam: No more memory\n");
+		I_Error("AddRamToSendQueue: No more memory\n");
 
 	// Initialise with zeros
 	memset(p, 0, sizeof (filetx_t));
@@ -749,11 +749,11 @@ void SV_SendRam(INT32 node, void *data, size_t size, freemethod_t freemethod, UI
   *
   * \param node The node to send the file to
   * \param filename The file to send
-  * \sa SV_SendFile
-  * \sa SV_SendRam
+  * \sa AddFileToSendQueue
+  * \sa AddRamToSendQueue
   *
   */
-boolean SV_SendLuaFile(INT32 node, const char *filename, boolean textmode)
+boolean AddLuaFileToSendQueue(INT32 node, const char *filename, boolean textmode)
 {
 	filetx_t **q; // A pointer to the "next" field of the last file in the list
 	filetx_t *p; // The new file request
@@ -770,7 +770,7 @@ boolean SV_SendLuaFile(INT32 node, const char *filename, boolean textmode)
 	// Allocate a file request and append it to the file list
 	p = *q = (filetx_t *)malloc(sizeof (filetx_t));
 	if (!p)
-		I_Error("SV_SendLuaFile: No more memory\n");
+		I_Error("AddLuaFileToSendQueue: No more memory\n");
 
 	// Initialise with zeros
 	memset(p, 0, sizeof (filetx_t));
@@ -778,7 +778,7 @@ boolean SV_SendLuaFile(INT32 node, const char *filename, boolean textmode)
 	// Allocate the file name
 	p->id.filename = (char *)malloc(MAX_WADPATH); // !!!
 	if (!p->id.filename)
-		I_Error("SV_SendLuaFile: No more memory\n");
+		I_Error("AddLuaFileToSendQueue: No more memory\n");
 
 	// Set the file name and get rid of the path
 	strlcpy(p->id.filename, filename, MAX_WADPATH); // !!!
@@ -804,7 +804,8 @@ static void SV_EndFileSend(INT32 node)
 {
 	filetx_t *p = transfer[node].txlist;
 
-	// Free the file request according to the freemethod parameter used with SV_SendFile/Ram
+	// Free the file request according to the freemethod
+	// parameter used with AddFileToSendQueue/AddRamToSendQueue
 	switch (p->ram)
 	{
 		case SF_FILE: // It's a file, close it and free its filename
@@ -842,7 +843,7 @@ static void SV_EndFileSend(INT32 node)
   *       especially when the one downloading has high latency
   *
   */
-void SV_FileSendTicker(void)
+void FileSendTicker(void)
 {
 	static INT32 currentnode = 0;
 	filetx_pak *p;
@@ -938,7 +939,7 @@ void SV_FileSendTicker(void)
 				if (f->textmode && feof(transfer[i].currentfile))
                     size = n;
 				else if (fread(p->data, 1, size, transfer[i].currentfile) != size)
-					I_Error("SV_FileSendTicker: can't read %s byte on %s at %d because %s", sizeu1(size), f->id.filename, transfer[i].position, M_FileError(transfer[i].currentfile));
+					I_Error("FileSendTicker: can't read %s byte on %s at %d because %s", sizeu1(size), f->id.filename, transfer[i].position, M_FileError(transfer[i].currentfile));
 			}
 		}
 		p->position = LONG(transfer[i].position);
@@ -965,7 +966,7 @@ void SV_FileSendTicker(void)
 	}
 }
 
-void Got_Filetxpak(void)
+void PT_FileFragment(void)
 {
 	INT32 filenum = netbuffer->u.filetxpak.fileid;
 	fileneeded_t *file = &fileneeded[filenum];
@@ -995,7 +996,7 @@ void Got_Filetxpak(void)
 	if (file->status == FS_REQUESTED)
 	{
 		if (file->file)
-			I_Error("Got_Filetxpak: already open file\n");
+			I_Error("PT_FileFragment: already open file\n");
 		file->file = fopen(filename, file->textmode ? "w" : "wb");
 		if (!file->file)
 			I_Error("Can't create file %s: %s", filename, strerror(errno));
@@ -1078,7 +1079,7 @@ void Got_Filetxpak(void)
  * \return True if the node is downloading a file
  *
  */
-boolean SV_SendingFile(INT32 node)
+boolean SendingFile(INT32 node)
 {
 	return transfer[node].txlist != NULL;
 }
diff --git a/src/d_netfil.h b/src/d_netfil.h
index 7d6efada0..f212e16f8 100644
--- a/src/d_netfil.h
+++ b/src/d_netfil.h
@@ -61,16 +61,16 @@ void CL_PrepareDownloadSaveGame(const char *tmpsave);
 
 INT32 CL_CheckFiles(void);
 void CL_LoadServerFiles(void);
-void SV_SendRam(INT32 node, void *data, size_t size, freemethod_t freemethod,
+void AddRamToSendQueue(INT32 node, void *data, size_t size, freemethod_t freemethod,
 	UINT8 fileid);
 
-void SV_FileSendTicker(void);
-void Got_Filetxpak(void);
-boolean SV_SendingFile(INT32 node);
+void FileSendTicker(void);
+void PT_FileFragment(void);
+boolean SendingFile(INT32 node);
 
 boolean CL_CheckDownloadable(void);
-boolean CL_SendRequestFile(void);
-boolean Got_RequestFilePak(INT32 node);
+boolean CL_SendFileRequest(void);
+boolean PT_RequestFile(INT32 node);
 
 typedef enum
 {
@@ -96,7 +96,7 @@ extern char luafiledir[256 + 16];
 
 void AddLuaFileTransfer(const char *filename, const char *mode);
 void SV_PrepareSendLuaFileToNextNode(void);
-boolean SV_SendLuaFile(INT32 node, const char *filename, boolean textmode);
+boolean AddLuaFileToSendQueue(INT32 node, const char *filename, boolean textmode);
 void SV_PrepareSendLuaFile(const char *filename);
 void SV_HandleLuaFileSent(UINT8 node);
 void RemoveLuaFileTransfer(void);
diff --git a/src/i_tcp.c b/src/i_tcp.c
index 373ea1bd0..5180869a5 100644
--- a/src/i_tcp.c
+++ b/src/i_tcp.c
@@ -487,7 +487,7 @@ static void cleanupnodes(void)
 
 	// Why can't I start at zero?
 	for (j = 1; j < MAXNETNODES; j++)
-		if (!(nodeingame[j] || SV_SendingFile(j)))
+		if (!(nodeingame[j] || SendingFile(j)))
 			nodeconnected[j] = false;
 }
 

From bf660dd35af7fe9e17e2641d3b82be9722d869c5 Mon Sep 17 00:00:00 2001
From: Louis-Antoine <lamr@free.fr>
Date: Tue, 12 May 2020 19:58:16 +0200
Subject: [PATCH 02/12] Rename local variables

---
 src/d_netfil.c | 44 ++++++++++++++++++++++----------------------
 1 file changed, 22 insertions(+), 22 deletions(-)

diff --git a/src/d_netfil.c b/src/d_netfil.c
index ec0a9b66c..f9d049be5 100644
--- a/src/d_netfil.c
+++ b/src/d_netfil.c
@@ -847,7 +847,7 @@ void FileSendTicker(void)
 {
 	static INT32 currentnode = 0;
 	filetx_pak *p;
-	size_t size;
+	size_t fragmentsize;
 	filetx_t *f;
 	INT32 packetsent, ram, i, j;
 	INT32 maxpacketsent;
@@ -926,33 +926,33 @@ void FileSendTicker(void)
 
 		// Build a packet containing a file fragment
 		p = &netbuffer->u.filetxpak;
-		size = software_MAXPACKETLENGTH - (FILETXHEADER + BASEPACKETSIZE);
-		if (f->size-transfer[i].position < size)
-			size = f->size-transfer[i].position;
+		fragmentsize = software_MAXPACKETLENGTH - (FILETXHEADER + BASEPACKETSIZE);
+		if (f->size-transfer[i].position < fragmentsize)
+			fragmentsize = f->size-transfer[i].position;
 		if (ram)
-			M_Memcpy(p->data, &f->id.ram[transfer[i].position], size);
+			M_Memcpy(p->data, &f->id.ram[transfer[i].position], fragmentsize);
 		else
 		{
-			size_t n = fread(p->data, 1, size, transfer[i].currentfile);
-			if (n != size) // Either an error or Windows turning CR-LF into LF
+			size_t n = fread(p->data, 1, fragmentsize, transfer[i].currentfile);
+			if (n != fragmentsize) // Either an error or Windows turning CR-LF into LF
 			{
 				if (f->textmode && feof(transfer[i].currentfile))
-                    size = n;
-				else if (fread(p->data, 1, size, transfer[i].currentfile) != size)
-					I_Error("FileSendTicker: can't read %s byte on %s at %d because %s", sizeu1(size), f->id.filename, transfer[i].position, M_FileError(transfer[i].currentfile));
+                    fragmentsize = n;
+				else if (fread(p->data, 1, fragmentsize, transfer[i].currentfile) != fragmentsize)
+					I_Error("FileSendTicker: can't read %s byte on %s at %d because %s", sizeu1(fragmentsize), f->id.filename, transfer[i].position, M_FileError(transfer[i].currentfile));
 			}
 		}
 		p->position = LONG(transfer[i].position);
 		// Put flag so receiver knows the total size
-		if (transfer[i].position + size == f->size || (f->textmode && feof(transfer[i].currentfile)))
+		if (transfer[i].position + fragmentsize == f->size || (f->textmode && feof(transfer[i].currentfile)))
 			p->position |= LONG(0x80000000);
 		p->fileid = f->fileid;
-		p->size = SHORT((UINT16)size);
+		p->size = SHORT((UINT16)fragmentsize);
 
 		// Send the packet
-		if (HSendPacket(i, true, 0, FILETXHEADER + size)) // Reliable SEND
+		if (HSendPacket(i, true, 0, FILETXHEADER + fragmentsize)) // Reliable SEND
 		{ // Success
-			transfer[i].position = (UINT32)(transfer[i].position + size);
+			transfer[i].position = (UINT32)(transfer[i].position + fragmentsize);
 			if (transfer[i].position == f->size || (f->textmode && feof(transfer[i].currentfile))) // Finish?
 				SV_EndFileSend(i);
 		}
@@ -1007,20 +1007,20 @@ void PT_FileFragment(void)
 
 	if (file->status == FS_DOWNLOADING)
 	{
-		UINT32 pos = LONG(netbuffer->u.filetxpak.position);
-		UINT16 size = SHORT(netbuffer->u.filetxpak.size);
+		UINT32 fragmentpos = LONG(netbuffer->u.filetxpak.position);
+		UINT16 fragmentsize = SHORT(netbuffer->u.filetxpak.size);
 		// Use a special trick to know when the file is complete (not always used)
 		// WARNING: file fragments can arrive out of order so don't stop yet!
-		if (pos & 0x80000000)
+		if (fragmentpos & 0x80000000)
 		{
-			pos &= ~0x80000000;
-			file->totalsize = pos + size;
+			fragmentpos &= ~0x80000000;
+			file->totalsize = fragmentpos + fragmentsize;
 		}
 		// We can receive packet in the wrong order, anyway all os support gaped file
-		fseek(file->file, pos, SEEK_SET);
-		if (size && fwrite(netbuffer->u.filetxpak.data,size,1,file->file) != 1)
+		fseek(file->file, fragmentpos, SEEK_SET);
+		if (fragmentsize && fwrite(netbuffer->u.filetxpak.data,fragmentsize,1,file->file) != 1)
 			I_Error("Can't write to %s: %s\n",filename, M_FileError(file->file));
-		file->currentsize += size;
+		file->currentsize += fragmentsize;
 
 		// Finished?
 		if (file->currentsize == file->totalsize)

From 3c7c758d176f6f3fb1f92da6e15799f839825080 Mon Sep 17 00:00:00 2001
From: Louis-Antoine <lamr@free.fr>
Date: Sat, 16 May 2020 22:09:00 +0200
Subject: [PATCH 03/12] Rewrite file transfer code

This code uses a custom packet acknowledgement system,
which is more suited for file transfer and does not suffer from
the small sender window used by the default acknowledgement system
---
 src/d_clisrv.c |  21 ++++
 src/d_clisrv.h |  21 +++-
 src/d_net.c    |   3 +
 src/d_netfil.c | 270 +++++++++++++++++++++++++++++++++++++------------
 src/d_netfil.h |  11 +-
 5 files changed, 262 insertions(+), 64 deletions(-)

diff --git a/src/d_clisrv.c b/src/d_clisrv.c
index a0a554609..a83d3033e 100644
--- a/src/d_clisrv.c
+++ b/src/d_clisrv.c
@@ -2103,6 +2103,9 @@ static boolean CL_ServerConnectionTicker(boolean viams, const char *tmpsave, tic
 			return false;
 		}
 
+		if (client && (cl_mode == CL_DOWNLOADFILES || cl_mode == CL_DOWNLOADSAVEGAME))
+			FileReceiveTicker();
+
 		// why are these here? this is for servers, we're a client
 		//if (key == 's' && server)
 		//	doomcom->numnodes = (INT16)pnumnodes;
@@ -3914,6 +3917,16 @@ static void HandlePacketFromAwayNode(SINT8 node)
 			PT_FileFragment();
 			break;
 
+		case PT_FILEACK:
+			if (server)
+				PT_FileAck();
+			break;
+
+		case PT_FILERECEIVED:
+			if (server)
+				PT_FileReceived();
+			break;
+
 		case PT_REQUESTFILE:
 			if (server)
 			{
@@ -4350,6 +4363,14 @@ static void HandlePacketFromPlayer(SINT8 node)
 			if (client)
 				PT_FileFragment();
 			break;
+		case PT_FILEACK:
+			if (server)
+				PT_FileAck();
+			break;
+		case PT_FILERECEIVED:
+			if (server)
+				PT_FileReceived();
+			break;
 		case PT_SENDINGLUAFILE:
 			if (client)
 				CL_PrepareDownloadLuaFile();
diff --git a/src/d_clisrv.h b/src/d_clisrv.h
index 463240a2a..cbae55017 100644
--- a/src/d_clisrv.h
+++ b/src/d_clisrv.h
@@ -75,6 +75,8 @@ typedef enum
 	                  // In addition, this packet can't occupy all the available slots.
 
 	PT_FILEFRAGMENT = PT_CANFAIL, // A part of a file.
+	PT_FILEACK,
+	PT_FILERECEIVED,
 
 	PT_TEXTCMD,       // Extra text commands from the client.
 	PT_TEXTCMD2,      // Splitscreen text commands.
@@ -320,13 +322,28 @@ typedef struct
 	UINT8 varlengthinputs[0]; // Playernames and netvars
 } ATTRPACK serverconfig_pak;
 
-typedef struct {
+typedef struct
+{
 	UINT8 fileid;
+	UINT32 filesize;
 	UINT32 position;
 	UINT16 size;
 	UINT8 data[0]; // Size is variable using hardware_MAXPACKETLENGTH
 } ATTRPACK filetx_pak;
 
+typedef struct
+{
+	UINT32 start;
+	UINT32 acks;
+} ATTRPACK fileacksegment_t;
+
+typedef struct
+{
+	UINT8 fileid;
+	UINT8 numsegments;
+	fileacksegment_t segments[0];
+} ATTRPACK fileack_pak;
+
 #ifdef _MSC_VER
 #pragma warning(default : 4200)
 #endif
@@ -442,6 +459,8 @@ typedef struct
 		UINT8 resynchgot;                   //
 		UINT8 textcmd[MAXTEXTCMD+1];        //       66049 bytes (wut??? 64k??? More like 257 bytes...)
 		filetx_pak filetxpak;               //         139 bytes
+		fileack_pak fileack;
+		UINT8 filereceived;
 		clientconfig_pak clientcfg;         //         136 bytes
 		UINT8 md5sum[16];
 		serverinfo_pak serverinfo;          //        1024 bytes
diff --git a/src/d_net.c b/src/d_net.c
index 1db75f3da..c0f97ca87 100644
--- a/src/d_net.c
+++ b/src/d_net.c
@@ -806,6 +806,9 @@ static const char *packettypename[NUMPACKETTYPE] =
 	"HASLUAFILE",
 
 	"FILEFRAGMENT",
+	"FILEACK",
+	"FILERECEIVED",
+
 	"TEXTCMD",
 	"TEXTCMD2",
 	"CLIENTJOIN",
diff --git a/src/d_netfil.c b/src/d_netfil.c
index f9d049be5..9dc09a15f 100644
--- a/src/d_netfil.c
+++ b/src/d_netfil.c
@@ -78,6 +78,8 @@ typedef struct filetran_s
 {
 	filetx_t *txlist; // Linked list of all files for the node
 	UINT32 position; // The current position in the file
+	boolean *ackedfragments;
+	UINT32 ackedsize;
 	FILE *currentfile; // The file currently being sent/received
 } filetran_t;
 static filetran_t transfer[MAXNETNODES];
@@ -88,6 +90,7 @@ static filetran_t transfer[MAXNETNODES];
 // Receiver structure
 INT32 fileneedednum; // Number of files needed to join the server
 fileneeded_t fileneeded[MAX_WADFILES]; // List of needed files
+static tic_t lasttimeackpacketsent = 0;
 char downloaddir[512] = "DOWNLOAD";
 
 #ifdef CLIENT_LOADINGSCREEN
@@ -159,6 +162,7 @@ void D_ParseFileneeded(INT32 fileneedednum_parm, UINT8 *fileneededstr)
 	for (i = 0; i < fileneedednum; i++)
 	{
 		fileneeded[i].status = FS_NOTFOUND; // We haven't even started looking for the file yet
+		fileneeded[i].justdownloaded = false;
 		filestatus = READUINT8(p); // The first byte is the file status
 		fileneeded[i].willsend = (UINT8)(filestatus >> 4);
 		fileneeded[i].totalsize = READUINT32(p); // The four next bytes are the file size
@@ -173,6 +177,7 @@ void CL_PrepareDownloadSaveGame(const char *tmpsave)
 {
 	fileneedednum = 1;
 	fileneeded[0].status = FS_REQUESTED;
+	fileneeded[0].justdownloaded = false;
 	fileneeded[0].totalsize = UINT32_MAX;
 	fileneeded[0].file = NULL;
 	memset(fileneeded[0].md5sum, 0, 16);
@@ -602,6 +607,7 @@ void CL_PrepareDownloadLuaFile(void)
 
 	fileneedednum = 1;
 	fileneeded[0].status = FS_REQUESTED;
+	fileneeded[0].justdownloaded = false;
 	fileneeded[0].totalsize = UINT32_MAX;
 	fileneeded[0].file = NULL;
 	memset(fileneeded[0].md5sum, 0, 16);
@@ -830,17 +836,17 @@ static void SV_EndFileSend(INT32 node)
 
 	// Indicate that the transmission is over
 	transfer[node].currentfile = NULL;
+	if (transfer[node].ackedfragments)
+		free(transfer[node].ackedfragments);
+	transfer[node].ackedfragments = NULL;
 
 	filestosend--;
 }
 
 #define PACKETPERTIC net_bandwidth/(TICRATE*software_MAXPACKETLENGTH)
+#define FILEFRAGMENTSIZE (software_MAXPACKETLENGTH - (FILETXHEADER + BASEPACKETSIZE))
 
 /** Handles file transmission
-  *
-  * \todo Use an acknowledging method more adapted to file transmission
-  *       The current download speed suffers from lack of ack packets,
-  *       especially when the one downloading has high latency
   *
   */
 void FileSendTicker(void)
@@ -850,23 +856,12 @@ void FileSendTicker(void)
 	size_t fragmentsize;
 	filetx_t *f;
 	INT32 packetsent, ram, i, j;
-	INT32 maxpacketsent;
 
 	if (!filestosend) // No file to send
 		return;
 
-	if (cv_downloadspeed.value) // New (and experimental) behavior
-	{
+	if (cv_downloadspeed.value) // New behavior
 		packetsent = cv_downloadspeed.value;
-		// Don't send more packets than we have free acks
-#ifndef NONET
-		maxpacketsent = Net_GetFreeAcks(false) - 5; // Let 5 extra acks just in case
-#else
-		maxpacketsent = 1;
-#endif
-		if (packetsent > maxpacketsent && maxpacketsent > 0) // Send at least one packet
-			packetsent = maxpacketsent;
-	}
 	else // Old behavior
 	{
 		packetsent = PACKETPERTIC;
@@ -883,11 +878,12 @@ void FileSendTicker(void)
 			i = (i+1) % MAXNETNODES, j++)
 		{
 			if (transfer[i].txlist)
-				goto found;
+				break;
 		}
 		// no transfer to do
-		I_Error("filestosend=%d but no file to send found\n", filestosend);
-	found:
+		if (j >= MAXNETNODES)
+			I_Error("filestosend=%d but no file to send found\n", filestosend);
+
 		currentnode = (i+1) % MAXNETNODES;
 		f = transfer[i].txlist;
 		ram = f->ram;
@@ -921,19 +917,37 @@ void FileSendTicker(void)
 			}
 			else // Sending RAM
 				transfer[i].currentfile = (FILE *)1; // Set currentfile to a non-null value to indicate that it is open
+
 			transfer[i].position = 0;
+			transfer[i].ackedsize = 0;
+
+			transfer[i].ackedfragments = calloc(f->size / FILEFRAGMENTSIZE + 1, sizeof(*transfer[i].ackedfragments));
+			if (!transfer[i].ackedfragments)
+				I_Error("FileSendTicker: No more memory\n");
+		}
+
+		// Find the first non-acknowledged fragment
+		while (transfer[i].ackedfragments[transfer[i].position / FILEFRAGMENTSIZE])
+		{
+			transfer[i].position += FILEFRAGMENTSIZE;
+			if (transfer[i].position >= f->size)
+				transfer[i].position = 0;
 		}
 
 		// Build a packet containing a file fragment
 		p = &netbuffer->u.filetxpak;
-		fragmentsize = software_MAXPACKETLENGTH - (FILETXHEADER + BASEPACKETSIZE);
+		fragmentsize = FILEFRAGMENTSIZE;
 		if (f->size-transfer[i].position < fragmentsize)
 			fragmentsize = f->size-transfer[i].position;
 		if (ram)
 			M_Memcpy(p->data, &f->id.ram[transfer[i].position], fragmentsize);
 		else
 		{
-			size_t n = fread(p->data, 1, fragmentsize, transfer[i].currentfile);
+			size_t n;
+
+			fseek(transfer[i].currentfile, transfer[i].position, SEEK_SET);
+
+			n = fread(p->data, 1, fragmentsize, transfer[i].currentfile);
 			if (n != fragmentsize) // Either an error or Windows turning CR-LF into LF
 			{
 				if (f->textmode && feof(transfer[i].currentfile))
@@ -943,35 +957,145 @@ void FileSendTicker(void)
 			}
 		}
 		p->position = LONG(transfer[i].position);
-		// Put flag so receiver knows the total size
-		if (transfer[i].position + fragmentsize == f->size || (f->textmode && feof(transfer[i].currentfile)))
-			p->position |= LONG(0x80000000);
 		p->fileid = f->fileid;
-		p->size = SHORT((UINT16)fragmentsize);
+		p->filesize = LONG(f->size);
+		p->size = SHORT((UINT16)FILEFRAGMENTSIZE);
 
 		// Send the packet
-		if (HSendPacket(i, true, 0, FILETXHEADER + fragmentsize)) // Reliable SEND
+		if (HSendPacket(i, false, 0, FILETXHEADER + fragmentsize)) // Don't use the default acknowledgement system
 		{ // Success
 			transfer[i].position = (UINT32)(transfer[i].position + fragmentsize);
-			if (transfer[i].position == f->size || (f->textmode && feof(transfer[i].currentfile))) // Finish?
-				SV_EndFileSend(i);
+			if (transfer[i].position >= f->size)
+				transfer[i].position = 0;
 		}
 		else
 		{ // Not sent for some odd reason, retry at next call
-			if (!ram)
-				fseek(transfer[i].currentfile,transfer[i].position, SEEK_SET);
 			// Exit the while (can't send this one so why should i send the next?)
 			break;
 		}
 	}
 }
 
+void PT_FileAck(void)
+{
+	fileack_pak *packet = &netbuffer->u.fileack;
+	INT32 node = doomcom->remotenode;
+	filetran_t *trans = &transfer[node];
+	INT32 i, j;
+
+	// Wrong file id? Ignore it, it's probably a late packet
+	if (!(trans->txlist && packet->fileid == trans->txlist->fileid))
+		return;
+
+	if (packet->numsegments * sizeof(*packet->segments) != doomcom->datalength - BASEPACKETSIZE - sizeof(*packet))
+	{
+		Net_CloseConnection(node);
+		return;
+	}
+
+	for (i = 0; i < packet->numsegments; i++)
+	{
+		fileacksegment_t *segment = &packet->segments[i];
+
+		for (j = 0; j < 32; j++)
+			if (LONG(segment->acks) & (1 << j))
+			{
+				if (LONG(segment->start) * FILEFRAGMENTSIZE >= trans->txlist->size)
+				{
+					Net_CloseConnection(node);
+					return;
+				}
+
+				if (!trans->ackedfragments[LONG(segment->start) + j])
+				{
+					trans->ackedfragments[LONG(segment->start) + j] = true;
+					trans->ackedsize += FILEFRAGMENTSIZE;
+
+					// If the last missing fragment was acked, finish!
+					if (trans->ackedsize == trans->txlist->size)
+					{
+						SV_EndFileSend(node);
+						return;
+					}
+				}
+			}
+	}
+}
+
+void PT_FileReceived(void)
+{
+	filetx_t *trans = transfer[doomcom->remotenode].txlist;
+
+	if (trans && netbuffer->u.filereceived == trans->fileid)
+		SV_EndFileSend(doomcom->remotenode);
+}
+
+static void SendAckPacket(fileack_pak *packet, UINT8 fileid)
+{
+	size_t packetsize;
+	INT32 i;
+
+	packetsize = sizeof(*packet) + packet->numsegments * sizeof(*packet->segments);
+
+	// Finalise the packet
+	packet->fileid = fileid;
+	for (i = 0; i < packet->numsegments; i++)
+	{
+		packet->segments[i].start = LONG(packet->segments[i].start);
+		packet->segments[i].acks = LONG(packet->segments[i].acks);
+	}
+
+	// Send the packet
+	netbuffer->packettype = PT_FILEACK;
+	M_Memcpy(&netbuffer->u.fileack, packet, packetsize);
+	HSendPacket(servernode, false, 0, packetsize);
+
+	// Clear the packet
+	memset(packet, 0, sizeof(*packet) + 512);
+}
+
+static void AddFragmentToAckPacket(fileack_pak *packet, UINT32 fragmentpos, UINT8 fileid)
+{
+	fileacksegment_t *segment = &packet->segments[packet->numsegments - 1];
+
+    if (packet->numsegments == 0
+		|| fragmentpos < segment->start
+		|| fragmentpos - segment->start >= 32)
+	{
+		// If the packet becomes too big, send it
+		if ((packet->numsegments + 1) * sizeof(*segment) > 512)
+			SendAckPacket(packet, fileid);
+
+		packet->numsegments++;
+		segment = &packet->segments[packet->numsegments - 1];
+		segment->start = fragmentpos;
+	}
+
+	// Set the bit that represents the fragment
+	segment->acks |= 1 << (fragmentpos - segment->start);
+}
+
+void FileReceiveTicker(void)
+{
+	INT32 i;
+
+	if (lasttimeackpacketsent - I_GetTime() > TICRATE / 2)
+		for (i = 0; i < fileneedednum; i++)
+			if (fileneeded[i].status == FS_DOWNLOADING)
+			{
+				SendAckPacket(fileneeded[i].ackpacket, i);
+				break;
+			}
+}
+
 void PT_FileFragment(void)
 {
 	INT32 filenum = netbuffer->u.filetxpak.fileid;
 	fileneeded_t *file = &fileneeded[filenum];
+	UINT32 fragmentpos = LONG(netbuffer->u.filetxpak.position);
+	UINT16 fragmentsize = SHORT(netbuffer->u.filetxpak.size);
+	UINT16 boundedfragmentsize = doomcom->datalength - BASEPACKETSIZE - sizeof(netbuffer->u.filetxpak);
 	char *filename;
-	static INT32 filetime = 0;
 
 	filename = va("%s", file->filename);
 	nameonly(filename);
@@ -997,48 +1121,74 @@ void PT_FileFragment(void)
 	{
 		if (file->file)
 			I_Error("PT_FileFragment: already open file\n");
+
 		file->file = fopen(filename, file->textmode ? "w" : "wb");
 		if (!file->file)
 			I_Error("Can't create file %s: %s", filename, strerror(errno));
+
 		CONS_Printf("\r%s...\n",filename);
 		file->currentsize = 0;
 		file->status = FS_DOWNLOADING;
+
+		file->totalsize = LONG(netbuffer->u.filetxpak.filesize);
+
+		file->receivedfragments = calloc(file->totalsize / fragmentsize + 1, sizeof(*file->receivedfragments));
+		file->ackpacket = calloc(1, sizeof(*file->ackpacket) + 512);
+		if (!(file->receivedfragments && file->ackpacket))
+			I_Error("FileSendTicker: No more memory\n");
+		lasttimeackpacketsent = I_GetTime();
 	}
 
 	if (file->status == FS_DOWNLOADING)
 	{
-		UINT32 fragmentpos = LONG(netbuffer->u.filetxpak.position);
-		UINT16 fragmentsize = SHORT(netbuffer->u.filetxpak.size);
-		// Use a special trick to know when the file is complete (not always used)
-		// WARNING: file fragments can arrive out of order so don't stop yet!
-		if (fragmentpos & 0x80000000)
-		{
-			fragmentpos &= ~0x80000000;
-			file->totalsize = fragmentpos + fragmentsize;
-		}
-		// We can receive packet in the wrong order, anyway all os support gaped file
-		fseek(file->file, fragmentpos, SEEK_SET);
-		if (fragmentsize && fwrite(netbuffer->u.filetxpak.data,fragmentsize,1,file->file) != 1)
-			I_Error("Can't write to %s: %s\n",filename, M_FileError(file->file));
-		file->currentsize += fragmentsize;
+		if (fragmentpos >= file->totalsize)
+			I_Error("Invalid file fragment\n");
 
-		// Finished?
-		if (file->currentsize == file->totalsize)
+		if (!file->receivedfragments[fragmentpos / fragmentsize]) // Not received yet
 		{
-			fclose(file->file);
-			file->file = NULL;
-			file->status = FS_FOUND;
-			CONS_Printf(M_GetText("Downloading %s...(done)\n"),
-				filename);
-			if (luafiletransfers)
+			file->receivedfragments[fragmentpos / fragmentsize] = true;
+
+			// We can receive packets in the wrong order, anyway all OSes support gaped files
+			fseek(file->file, fragmentpos, SEEK_SET);
+			if (fragmentsize && fwrite(netbuffer->u.filetxpak.data, boundedfragmentsize, 1, file->file) != 1)
+				I_Error("Can't write to %s: %s\n",filename, M_FileError(file->file));
+			file->currentsize += boundedfragmentsize;
+
+			AddFragmentToAckPacket(file->ackpacket, fragmentpos / fragmentsize, filenum);
+
+			// Finished?
+			if (file->currentsize == file->totalsize)
 			{
+				fclose(file->file);
+				file->file = NULL;
+				free(file->receivedfragments);
+				free(file->ackpacket);
+				file->status = FS_FOUND;
+				file->justdownloaded = true;
+				CONS_Printf(M_GetText("Downloading %s...(done)\n"),
+					filename);
+
 				// Tell the server we have received the file
-				netbuffer->packettype = PT_HASLUAFILE;
-				HSendPacket(servernode, true, 0, 0);
+				netbuffer->packettype = PT_FILERECEIVED;
+				netbuffer->u.filereceived = filenum;
+				HSendPacket(servernode, true, 0, 1);
+
+				if (luafiletransfers)
+				{
+					// Tell the server we have received the file
+					netbuffer->packettype = PT_HASLUAFILE;
+					HSendPacket(servernode, true, 0, 0);
+				}
 			}
 		}
+		else // Already received
+		{
+			// If they are sending us the fragment again, it's probably because
+			// they missed our previous ack, so we must re-acknowledge it
+			AddFragmentToAckPacket(file->ackpacket, fragmentpos / fragmentsize, filenum);
+		}
 	}
-	else
+	else if (!file->justdownloaded)
 	{
 		const char *s;
 		switch(file->status)
@@ -1061,12 +1211,6 @@ void PT_FileFragment(void)
 		}
 		I_Error("Received a file not requested (file id: %d, file status: %s)\n", filenum, s);
 	}
-	// Send ack back quickly
-	if (++filetime == 3)
-	{
-		Net_SendAcks(servernode);
-		filetime = 0;
-	}
 
 #ifdef CLIENT_LOADINGSCREEN
 	lastfilenum = filenum;
@@ -1108,6 +1252,8 @@ void CloseNetFile(void)
 		if (fileneeded[i].status == FS_DOWNLOADING && fileneeded[i].file)
 		{
 			fclose(fileneeded[i].file);
+			free(fileneeded[i].receivedfragments);
+			free(fileneeded[i].ackpacket);
 			// File is not complete delete it
 			remove(fileneeded[i].filename);
 		}
diff --git a/src/d_netfil.h b/src/d_netfil.h
index f212e16f8..c87ff6f8c 100644
--- a/src/d_netfil.h
+++ b/src/d_netfil.h
@@ -14,6 +14,7 @@
 #define __D_NETFIL__
 
 #include "d_net.h"
+#include "d_clisrv.h"
 #include "w_wad.h"
 
 typedef enum
@@ -41,9 +42,13 @@ typedef struct
 	UINT8 md5sum[16];
 	// Used only for download
 	FILE *file;
+	boolean *receivedfragments;
+	fileack_pak *ackpacket;
+	tic_t lasttimeackpacketsent;
 	UINT32 currentsize;
 	UINT32 totalsize;
 	filestatus_t status; // The value returned by recsearch
+	boolean justdownloaded; // To prevent late fragments from causing an I_Error
 	boolean textmode; // For files requested by Lua without the "b" option
 } fileneeded_t;
 
@@ -65,9 +70,13 @@ void AddRamToSendQueue(INT32 node, void *data, size_t size, freemethod_t freemet
 	UINT8 fileid);
 
 void FileSendTicker(void);
-void PT_FileFragment(void);
+void PT_FileAck(void);
+void PT_FileReceived(void);
 boolean SendingFile(INT32 node);
 
+void FileReceiveTicker(void);
+void PT_FileFragment(void);
+
 boolean CL_CheckDownloadable(void);
 boolean CL_SendFileRequest(void);
 boolean PT_RequestFile(INT32 node);

From 66ecfb741a34179662b5a536baf75f91b91331d1 Mon Sep 17 00:00:00 2001
From: Louis-Antoine <lamr@free.fr>
Date: Sat, 16 May 2020 22:49:20 +0200
Subject: [PATCH 04/12] Show total size when downloading gamestate

---
 src/d_clisrv.c | 19 ++++++++++++++++---
 src/d_netfil.c |  4 ++++
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/src/d_clisrv.c b/src/d_clisrv.c
index a83d3033e..089d967af 100644
--- a/src/d_clisrv.c
+++ b/src/d_clisrv.c
@@ -1180,8 +1180,9 @@ static inline void CL_DrawConnectionStatus(void)
 		// 15 pal entries total.
 		const char *cltext;
 
-		for (i = 0; i < 16; ++i)
-			V_DrawFill((BASEVIDWIDTH/2-128) + (i * 16), BASEVIDHEIGHT-24, 16, 8, palstart + ((animtime - i) & 15));
+		if (!(cl_mode == CL_DOWNLOADSAVEGAME && lastfilenum != -1))
+			for (i = 0; i < 16; ++i)
+				V_DrawFill((BASEVIDWIDTH/2-128) + (i * 16), BASEVIDHEIGHT-24, 16, 8, palstart + ((animtime - i) & 15));
 
 		switch (cl_mode)
 		{
@@ -1189,10 +1190,22 @@ static inline void CL_DrawConnectionStatus(void)
 			case CL_DOWNLOADSAVEGAME:
 				if (lastfilenum != -1)
 				{
+					UINT32 currentsize = fileneeded[lastfilenum].currentsize;
+					UINT32 totalsize = fileneeded[lastfilenum].totalsize;
+					INT32 dldlength;
+
 					cltext = M_GetText("Downloading game state...");
 					Net_GetNetStat();
+
+					dldlength = (INT32)((currentsize/(double)totalsize) * 256);
+					if (dldlength > 256)
+						dldlength = 256;
+					V_DrawFill(BASEVIDWIDTH/2-128, BASEVIDHEIGHT-24, 256, 8, 111);
+					V_DrawFill(BASEVIDWIDTH/2-128, BASEVIDHEIGHT-24, dldlength, 8, 96);
+
 					V_DrawString(BASEVIDWIDTH/2-128, BASEVIDHEIGHT-24, V_20TRANS|V_MONOSPACE,
-						va(" %4uK",fileneeded[lastfilenum].currentsize>>10));
+						va(" %4uK/%4uK",currentsize>>10,totalsize>>10));
+
 					V_DrawRightAlignedString(BASEVIDWIDTH/2+128, BASEVIDHEIGHT-24, V_20TRANS|V_MONOSPACE,
 						va("%3.1fK/s ", ((double)getbps)/1024));
 				}
diff --git a/src/d_netfil.c b/src/d_netfil.c
index 9dc09a15f..690a5e162 100644
--- a/src/d_netfil.c
+++ b/src/d_netfil.c
@@ -175,6 +175,10 @@ void D_ParseFileneeded(INT32 fileneedednum_parm, UINT8 *fileneededstr)
 
 void CL_PrepareDownloadSaveGame(const char *tmpsave)
 {
+#ifdef CLIENT_LOADINGSCREEN
+	lastfilenum = -1;
+#endif
+
 	fileneedednum = 1;
 	fileneeded[0].status = FS_REQUESTED;
 	fileneeded[0].justdownloaded = false;

From db85c62c6fb2a5066a3ce37a6f99a4df93518520 Mon Sep 17 00:00:00 2001
From: Louis-Antoine <lamr@free.fr>
Date: Tue, 19 May 2020 11:28:24 +0200
Subject: [PATCH 05/12] Allow resuming the most recent file transfer

---
 src/d_netfil.c      | 146 +++++++++++++++++++++++++++++++++++++-------
 src/d_netfil.h      |   4 +-
 src/sdl/i_system.c  |   3 +
 src/win32/win_sys.c |   3 +
 4 files changed, 132 insertions(+), 24 deletions(-)

diff --git a/src/d_netfil.c b/src/d_netfil.c
index 690a5e162..b5647ebe2 100644
--- a/src/d_netfil.c
+++ b/src/d_netfil.c
@@ -93,6 +93,17 @@ fileneeded_t fileneeded[MAX_WADFILES]; // List of needed files
 static tic_t lasttimeackpacketsent = 0;
 char downloaddir[512] = "DOWNLOAD";
 
+// For resuming failed downloads
+typedef struct
+{
+	char filename[MAX_WADPATH];
+	UINT8 md5sum[16];
+	boolean *receivedfragments;
+	UINT32 fragmentsize;
+	UINT32 currentsize;
+} pauseddownload_t;
+static pauseddownload_t *pauseddownload = NULL;
+
 #ifdef CLIENT_LOADINGSCREEN
 // for cl loading screen
 INT32 lastfilenum = -1;
@@ -255,6 +266,31 @@ boolean CL_CheckDownloadable(void)
 	return false;
 }
 
+/** Returns true if a needed file transfer can be resumed
+  *
+  * \param file The needed file to resume the transfer for
+  * \return True if the transfer can be resumed
+  *
+  */
+static boolean CL_CanResumeDownload(fileneeded_t *file)
+{
+	return pauseddownload
+		&& !strcmp(pauseddownload->filename, file->filename) // Same name
+		&& !memcmp(pauseddownload->md5sum, file->md5sum, 16) // Same checksum
+		&& pauseddownload->fragmentsize == file->fragmentsize; // Same fragment size
+}
+
+void CL_AbortDownloadResume(void)
+{
+	if (!pauseddownload)
+		return;
+
+	free(pauseddownload->receivedfragments);
+	remove(pauseddownload->filename);
+	free(pauseddownload);
+	pauseddownload = NULL;
+}
+
 /** Sends requests for files in the ::fileneeded table with a status of
   * ::FS_NOTFOUND.
   *
@@ -630,7 +666,7 @@ static INT32 filestosend = 0;
   *
   * \param node The node to send the file to
   * \param filename The file to send
-  * \param fileid ???
+  * \param fileid The index of the file in the list of added files
   * \sa AddRamToSendQueue
   * \sa AddLuaFileToSendQueue
   *
@@ -721,7 +757,7 @@ static boolean AddFileToSendQueue(INT32 node, const char *filename, UINT8 fileid
   * \param data The memory block to send
   * \param size The size of the block in bytes
   * \param freemethod How to free the block after it has been sent
-  * \param fileid ???
+  * \param fileid The index of the file in the list of added files
   * \sa AddFileToSendQueue
   * \sa AddLuaFileToSendQueue
   *
@@ -1083,13 +1119,36 @@ void FileReceiveTicker(void)
 {
 	INT32 i;
 
-	if (lasttimeackpacketsent - I_GetTime() > TICRATE / 2)
-		for (i = 0; i < fileneedednum; i++)
-			if (fileneeded[i].status == FS_DOWNLOADING)
+	for (i = 0; i < fileneedednum; i++)
+	{
+		fileneeded_t *file = &fileneeded[i];
+
+		if (file->status == FS_DOWNLOADING)
+		{
+			if (lasttimeackpacketsent - I_GetTime() > TICRATE / 2)
+				SendAckPacket(file->ackpacket, i);
+
+			// When resuming a tranfer, start with telling
+			// the server what parts we already received
+			if (file->ackresendposition != UINT32_MAX && file->status == FS_DOWNLOADING)
 			{
-				SendAckPacket(fileneeded[i].ackpacket, i);
-				break;
+				// Acknowledge ~70 MB/s, whichs means the client sends ~18 KB/s
+				INT32 j;
+				for (j = 0; j < 2048; j++)
+				{
+					if (file->receivedfragments[file->ackresendposition])
+						AddFragmentToAckPacket(file->ackpacket, file->ackresendposition, i);
+
+					file->ackresendposition++;
+					if (file->ackresendposition * file->fragmentsize >= file->totalsize)
+					{
+						file->ackresendposition = UINT32_MAX;
+						break;
+					}
+				}
 			}
+		}
+	}
 }
 
 void PT_FileFragment(void)
@@ -1126,20 +1185,47 @@ void PT_FileFragment(void)
 		if (file->file)
 			I_Error("PT_FileFragment: already open file\n");
 
-		file->file = fopen(filename, file->textmode ? "w" : "wb");
-		if (!file->file)
-			I_Error("Can't create file %s: %s", filename, strerror(errno));
-
-		CONS_Printf("\r%s...\n",filename);
-		file->currentsize = 0;
 		file->status = FS_DOWNLOADING;
+		file->fragmentsize = fragmentsize;
 
-		file->totalsize = LONG(netbuffer->u.filetxpak.filesize);
-
-		file->receivedfragments = calloc(file->totalsize / fragmentsize + 1, sizeof(*file->receivedfragments));
 		file->ackpacket = calloc(1, sizeof(*file->ackpacket) + 512);
-		if (!(file->receivedfragments && file->ackpacket))
+		if (!file->ackpacket)
 			I_Error("FileSendTicker: No more memory\n");
+
+		if (CL_CanResumeDownload(file))
+		{
+			file->file = fopen(filename, file->textmode ? "r+" : "r+b");
+			if (!file->file)
+				I_Error("Can't reopen file %s: %s", filename, strerror(errno));
+			CONS_Printf("\r%s...\n", filename);
+
+			CONS_Printf("Resuming download...\n");
+			file->currentsize = pauseddownload->currentsize;
+			file->receivedfragments = pauseddownload->receivedfragments;
+			file->ackresendposition = 0;
+
+			free(pauseddownload);
+			pauseddownload = NULL;
+		}
+		else
+		{
+			CL_AbortDownloadResume();
+
+			file->file = fopen(filename, file->textmode ? "w" : "wb");
+			if (!file->file)
+				I_Error("Can't create file %s: %s", filename, strerror(errno));
+
+			CONS_Printf("\r%s...\n",filename);
+
+			file->currentsize = 0;
+			file->totalsize = LONG(netbuffer->u.filetxpak.filesize);
+			file->ackresendposition = UINT32_MAX; // Only used for resumed downloads
+
+			file->receivedfragments = calloc(file->totalsize / fragmentsize + 1, sizeof(*file->receivedfragments));
+			if (!file->receivedfragments)
+				I_Error("FileSendTicker: No more memory\n");
+		}
+
 		lasttimeackpacketsent = I_GetTime();
 	}
 
@@ -1256,14 +1342,28 @@ void CloseNetFile(void)
 		if (fileneeded[i].status == FS_DOWNLOADING && fileneeded[i].file)
 		{
 			fclose(fileneeded[i].file);
-			free(fileneeded[i].receivedfragments);
 			free(fileneeded[i].ackpacket);
-			// File is not complete delete it
-			remove(fileneeded[i].filename);
-		}
 
-	// Remove PT_FILEFRAGMENT from acknowledge list
-	Net_AbortPacketType(PT_FILEFRAGMENT);
+			if (!pauseddownload && i != 0) // 0 is either srb2.srb or the gamestate...
+			{
+				// Don't remove the file, save it for later in case we resume the download
+				pauseddownload = malloc(sizeof(*pauseddownload));
+				if (!pauseddownload)
+					I_Error("CloseNetFile: No more memory\n");
+
+				strcpy(pauseddownload->filename, fileneeded[i].filename);
+				memcpy(pauseddownload->md5sum, fileneeded[i].md5sum, 16);
+				pauseddownload->currentsize = fileneeded[i].currentsize;
+				pauseddownload->receivedfragments = fileneeded[i].receivedfragments;
+				pauseddownload->fragmentsize = fileneeded[i].fragmentsize;
+			}
+			else
+			{
+				free(fileneeded[i].receivedfragments);
+				// File is not complete delete it
+				remove(fileneeded[i].filename);
+			}
+		}
 }
 
 // Functions cut and pasted from Doomatic :)
diff --git a/src/d_netfil.h b/src/d_netfil.h
index c87ff6f8c..171b3920f 100644
--- a/src/d_netfil.h
+++ b/src/d_netfil.h
@@ -43,10 +43,11 @@ typedef struct
 	// Used only for download
 	FILE *file;
 	boolean *receivedfragments;
+	UINT32 fragmentsize;
 	fileack_pak *ackpacket;
-	tic_t lasttimeackpacketsent;
 	UINT32 currentsize;
 	UINT32 totalsize;
+	UINT32 ackresendposition; // Used when resuming downloads
 	filestatus_t status; // The value returned by recsearch
 	boolean justdownloaded; // To prevent late fragments from causing an I_Error
 	boolean textmode; // For files requested by Lua without the "b" option
@@ -119,6 +120,7 @@ void MakePathDirs(char *path);
 
 void SV_AbortSendFiles(INT32 node);
 void CloseNetFile(void);
+void CL_AbortDownloadResume(void);
 
 boolean fileexist(char *filename, time_t ptime);
 
diff --git a/src/sdl/i_system.c b/src/sdl/i_system.c
index d2ed62516..e5cdb3206 100644
--- a/src/sdl/i_system.c
+++ b/src/sdl/i_system.c
@@ -293,6 +293,7 @@ static void I_ReportSignal(int num, int coredumped)
 FUNCNORETURN static ATTRNORETURN void signal_handler(INT32 num)
 {
 	D_QuitNetGame(); // Fix server freezes
+	CL_AbortDownloadResume();
 	I_ReportSignal(num, 0);
 	I_ShutdownSystem();
 	signal(num, SIG_DFL);               //default signal action
@@ -2293,6 +2294,7 @@ void I_Quit(void)
 		G_StopMetalRecording(false);
 
 	D_QuitNetGame();
+	CL_AbortDownloadResume();
 	I_ShutdownMusic();
 	I_ShutdownSound();
 	I_ShutdownCD();
@@ -2409,6 +2411,7 @@ void I_Error(const char *error, ...)
 		G_StopMetalRecording(false);
 
 	D_QuitNetGame();
+	CL_AbortDownloadResume();
 	I_ShutdownMusic();
 	I_ShutdownSound();
 	I_ShutdownCD();
diff --git a/src/win32/win_sys.c b/src/win32/win_sys.c
index f9d66be7f..fb0742c5a 100644
--- a/src/win32/win_sys.c
+++ b/src/win32/win_sys.c
@@ -465,6 +465,7 @@ static void signal_handler(int num)
 	char sigdef[64];
 
 	D_QuitNetGame(); // Fix server freezes
+	CL_AbortDownloadResume();
 	I_ShutdownSystem();
 
 	switch (num)
@@ -650,6 +651,7 @@ void I_Error(const char *error, ...)
 		G_StopMetalRecording(false);
 
 	D_QuitNetGame();
+	CL_AbortDownloadResume();
 
 	// shutdown everything that was started
 	I_ShutdownSystem();
@@ -745,6 +747,7 @@ void I_Quit(void)
 	// or something else that will be finished by I_ShutdownSystem(),
 	// so do it before.
 	D_QuitNetGame();
+	CL_AbortDownloadResume();
 
 	// shutdown everything that was started
 	I_ShutdownSystem();

From 06d3af671634779a640c15a3fe9f9c953635aaa6 Mon Sep 17 00:00:00 2001
From: Louis-Antoine <lamr@free.fr>
Date: Tue, 19 May 2020 15:16:51 +0200
Subject: [PATCH 06/12] Refactor Lua file transfer code

---
 src/blua/liolib.c | 11 +----------
 src/d_netfil.c    | 43 ++++++++++++++++++++++---------------------
 2 files changed, 23 insertions(+), 31 deletions(-)

diff --git a/src/blua/liolib.c b/src/blua/liolib.c
index b43052194..ce630a20b 100644
--- a/src/blua/liolib.c
+++ b/src/blua/liolib.c
@@ -314,16 +314,7 @@ void Got_LuaFile(UINT8 **cp, INT32 playernum)
 	RemoveLuaFileTransfer();
 
 	if (server && luafiletransfers)
-	{
-		if (FIL_FileOK(luafiletransfers->realfilename))
-			SV_PrepareSendLuaFileToNextNode();
-		else
-		{
-			// Send a net command with 0 as its first byte to indicate the file couldn't be opened
-			success = 0;
-			SendNetXCmd(XD_LUAFILE, &success, 1);
-		}
-	}
+		SV_PrepareSendLuaFile();
 }
 
 
diff --git a/src/d_netfil.c b/src/d_netfil.c
index b5647ebe2..2262a1f93 100644
--- a/src/d_netfil.c
+++ b/src/d_netfil.c
@@ -538,26 +538,9 @@ void AddLuaFileTransfer(const char *filename, const char *mode)
 
 	strlcpy(filetransfer->mode, mode, sizeof(filetransfer->mode));
 
-	if (server)
-	{
-		INT32 i;
-
-		// Set status to "waiting" for everyone
-		for (i = 0; i < MAXNETNODES; i++)
-			filetransfer->nodestatus[i] = LFTNS_WAITING;
-
-		if (!luafiletransfers->next) // Only if there is no transfer already going on
-		{
-			if (FIL_ReadFileOK(filetransfer->realfilename))
-				SV_PrepareSendLuaFileToNextNode();
-			else
-			{
-				// Send a net command with 0 as its first byte to indicate the file couldn't be opened
-				UINT8 success = 0;
-				SendNetXCmd(XD_LUAFILE, &success, 1);
-			}
-		}
-	}
+	// Only if there is no transfer already going on
+	if (server && filetransfer == luafiletransfers)
+		SV_PrepareSendLuaFile();
 
 	// Store the callback so it can be called once everyone has the file
 	filetransfer->id = id;
@@ -571,7 +554,7 @@ void AddLuaFileTransfer(const char *filename, const char *mode)
 	}
 }
 
-void SV_PrepareSendLuaFileToNextNode(void)
+static void SV_PrepareSendLuaFileToNextNode(void)
 {
 	INT32 i;
 	UINT8 success = 1;
@@ -595,6 +578,24 @@ void SV_PrepareSendLuaFileToNextNode(void)
 	SendNetXCmd(XD_LUAFILE, &success, 1);
 }
 
+void SV_PrepareSendLuaFile(void)
+{
+	INT32 i;
+
+	// Set status to "waiting" for everyone
+	for (i = 0; i < MAXNETNODES; i++)
+		luafiletransfers->nodestatus[i] = LFTNS_WAITING;
+
+	if (FIL_ReadFileOK(luafiletransfers->realfilename))
+		SV_PrepareSendLuaFileToNextNode();
+	else
+	{
+		// Send a net command with 0 as its first byte to indicate the file couldn't be opened
+		UINT8 success = 0;
+		SendNetXCmd(XD_LUAFILE, &success, 1);
+	}
+}
+
 void SV_HandleLuaFileSent(UINT8 node)
 {
 	luafiletransfers->nodestatus[node] = LFTNS_SENT;

From 34c5da39e25a4ecffea860d08086861c31b93d8b Mon Sep 17 00:00:00 2001
From: Louis-Antoine <lamr@free.fr>
Date: Tue, 19 May 2020 20:00:58 +0200
Subject: [PATCH 07/12] Create FIL_ConvertTextFileToBinary

---
 src/m_misc.c | 38 ++++++++++++++++++++++++++++++++++++++
 src/m_misc.h |  2 ++
 2 files changed, 40 insertions(+)

diff --git a/src/m_misc.c b/src/m_misc.c
index 920a13198..c527d2296 100644
--- a/src/m_misc.c
+++ b/src/m_misc.c
@@ -297,6 +297,44 @@ size_t FIL_ReadFileTag(char const *name, UINT8 **buffer, INT32 tag)
 	return length;
 }
 
+/** Makes a copy of a text file with all newlines converted into LF newlines.
+  *
+  * \param textfilename The name of the source file
+  * \param binfilename The name of the destination file
+  */
+boolean FIL_ConvertTextFileToBinary(const char *textfilename, const char *binfilename)
+{
+	FILE *textfile;
+	FILE *binfile;
+	UINT8 buffer[1024];
+	size_t count;
+	boolean success;
+
+	textfile = fopen(textfilename, "r");
+	if (!textfile)
+		return false;
+
+	binfile = fopen(binfilename, "wb");
+	if (!binfile)
+	{
+		fclose(textfile);
+		return false;
+	}
+
+	do
+	{
+		count = fread(buffer, 1, sizeof(buffer), textfile);
+		fwrite(buffer, 1, count, binfile);
+	} while (count);
+
+	success = !(ferror(textfile) || ferror(binfile));
+
+	fclose(textfile);
+	fclose(binfile);
+
+	return success;
+}
+
 /** Check if the filename exists
   *
   * \param name   Filename to check.
diff --git a/src/m_misc.h b/src/m_misc.h
index d64faea59..dbded37d0 100644
--- a/src/m_misc.h
+++ b/src/m_misc.h
@@ -48,6 +48,8 @@ boolean FIL_WriteFile(char const *name, const void *source, size_t length);
 size_t FIL_ReadFileTag(char const *name, UINT8 **buffer, INT32 tag);
 #define FIL_ReadFile(n, b) FIL_ReadFileTag(n, b, PU_STATIC)
 
+boolean FIL_ConvertTextFileToBinary(const char *textfilename, const char *binfilename);
+
 boolean FIL_FileExists(const char *name);
 boolean FIL_WriteFileOK(char const *name);
 boolean FIL_ReadFileOK(char const *name);

From f620b52672870e82684e0d87ba0c73e1889315c5 Mon Sep 17 00:00:00 2001
From: Louis-Antoine <lamr@free.fr>
Date: Tue, 19 May 2020 21:36:21 +0200
Subject: [PATCH 08/12] Fix sending Lua files in text mode

---
 src/blua/liolib.c | 10 ++++++++-
 src/d_clisrv.c    |  6 +-----
 src/d_netfil.c    | 52 ++++++++++++++++++++++++++---------------------
 src/d_netfil.h    |  6 ++----
 4 files changed, 41 insertions(+), 33 deletions(-)

diff --git a/src/blua/liolib.c b/src/blua/liolib.c
index ce630a20b..2ccfa70e8 100644
--- a/src/blua/liolib.c
+++ b/src/blua/liolib.c
@@ -284,8 +284,16 @@ void Got_LuaFile(UINT8 **cp, INT32 playernum)
 	// Push the first argument (file handle or nil) on the stack
 	if (success)
 	{
+		char mode[4];
+
+		// Ensure we are opening in binary mode
+		// (if it's a text file, newlines have been converted already)
+		strcpy(mode, luafiletransfers->mode);
+		if (!strchr(mode, 'b'))
+			strcat(mode, "b");
+
 		pf = newfile(gL); // Create and push the file handle
-		*pf = fopen(luafiletransfers->realfilename, luafiletransfers->mode); // Open the file
+		*pf = fopen(luafiletransfers->realfilename, mode); // Open the file
 		if (!*pf)
 			I_Error("Can't open file \"%s\"\n", luafiletransfers->realfilename); // The file SHOULD exist
 	}
diff --git a/src/d_clisrv.c b/src/d_clisrv.c
index 089d967af..275eb790e 100644
--- a/src/d_clisrv.c
+++ b/src/d_clisrv.c
@@ -4239,11 +4239,7 @@ static void HandlePacketFromPlayer(SINT8 node)
 			break;
 		case PT_ASKLUAFILE:
 			if (server && luafiletransfers && luafiletransfers->nodestatus[node] == LFTNS_ASKED)
-			{
-				char *name = va("%s" PATHSEP "%s", luafiledir, luafiletransfers->filename);
-				boolean textmode = !strchr(luafiletransfers->mode, 'b');
-				AddLuaFileToSendQueue(node, name, textmode);
-			}
+				AddLuaFileToSendQueue(node, luafiletransfers->realfilename);
 			break;
 		case PT_HASLUAFILE:
 			if (server && luafiletransfers && luafiletransfers->nodestatus[node] == LFTNS_SENDING)
diff --git a/src/d_netfil.c b/src/d_netfil.c
index 2262a1f93..da190bc5c 100644
--- a/src/d_netfil.c
+++ b/src/d_netfil.c
@@ -69,7 +69,6 @@ typedef struct filetx_s
 	UINT32 size; // Size of the file
 	UINT8 fileid;
 	INT32 node; // Destination
-	boolean textmode; // For files requested by Lua without the "b" option
 	struct filetx_s *next; // Next file in the list
 } filetx_t;
 
@@ -180,7 +179,6 @@ void D_ParseFileneeded(INT32 fileneedednum_parm, UINT8 *fileneededstr)
 		fileneeded[i].file = NULL; // The file isn't open yet
 		READSTRINGN(p, fileneeded[i].filename, MAX_WADPATH); // The next bytes are the file name
 		READMEM(p, fileneeded[i].md5sum, 16); // The last 16 bytes are the file checksum
-		fileneeded[i].textmode = false;
 	}
 }
 
@@ -197,7 +195,6 @@ void CL_PrepareDownloadSaveGame(const char *tmpsave)
 	fileneeded[0].file = NULL;
 	memset(fileneeded[0].md5sum, 0, 16);
 	strcpy(fileneeded[0].filename, tmpsave);
-	fileneeded[0].textmode = false;
 }
 
 /** Checks the server to see if we CAN download all the files,
@@ -507,8 +504,6 @@ void AddLuaFileTransfer(const char *filename, const char *mode)
 	luafiletransfer_t *filetransfer;
 	static INT32 id;
 
-	//CONS_Printf("AddLuaFileTransfer \"%s\"\n", filename);
-
 	// Find the last transfer in the list and set a pointer to its "next" field
 	prevnext = &luafiletransfers;
 	while (*prevnext)
@@ -580,6 +575,7 @@ static void SV_PrepareSendLuaFileToNextNode(void)
 
 void SV_PrepareSendLuaFile(void)
 {
+	char *binfilename;
 	INT32 i;
 
 	// Set status to "waiting" for everyone
@@ -587,7 +583,25 @@ void SV_PrepareSendLuaFile(void)
 		luafiletransfers->nodestatus[i] = LFTNS_WAITING;
 
 	if (FIL_ReadFileOK(luafiletransfers->realfilename))
+	{
+		// If opening in text mode, convert all newlines to LF
+		if (!strchr(luafiletransfers->mode, 'b'))
+		{
+			binfilename = strdup(va("%s" PATHSEP "$$$%d%d.tmp",
+				luafiledir, rand(), rand()));
+			if (!binfilename)
+				I_Error("SV_PrepareSendLuaFile: Out of memory\n");
+
+			if (!FIL_ConvertTextFileToBinary(luafiletransfers->realfilename, binfilename))
+				I_Error("SV_PrepareSendLuaFile: Failed to convert file newlines\n");
+
+			// Use the temporary file instead
+			free(luafiletransfers->realfilename);
+			luafiletransfers->realfilename = binfilename;
+		}
+
 		SV_PrepareSendLuaFileToNextNode();
+	}
 	else
 	{
 		// Send a net command with 0 as its first byte to indicate the file couldn't be opened
@@ -606,6 +620,10 @@ void RemoveLuaFileTransfer(void)
 {
 	luafiletransfer_t *filetransfer = luafiletransfers;
 
+	// If it was a temporary file, delete it
+	if (server && !strchr(filetransfer->mode, 'b'))
+		remove(filetransfer->realfilename);
+
 	RemoveLuaFileCallback(filetransfer->id);
 
 	luafiletransfers = filetransfer->next;
@@ -653,7 +671,6 @@ void CL_PrepareDownloadLuaFile(void)
 	fileneeded[0].file = NULL;
 	memset(fileneeded[0].md5sum, 0, 16);
 	strcpy(fileneeded[0].filename, luafiletransfers->realfilename);
-	fileneeded[0].textmode = !strchr(luafiletransfers->mode, 'b');
 
 	// Make sure all directories in the file path exist
 	MakePathDirs(fileneeded[0].filename);
@@ -800,7 +817,7 @@ void AddRamToSendQueue(INT32 node, void *data, size_t size, freemethod_t freemet
   * \sa AddRamToSendQueue
   *
   */
-boolean AddLuaFileToSendQueue(INT32 node, const char *filename, boolean textmode)
+boolean AddLuaFileToSendQueue(INT32 node, const char *filename)
 {
 	filetx_t **q; // A pointer to the "next" field of the last file in the list
 	filetx_t *p; // The new file request
@@ -831,9 +848,6 @@ boolean AddLuaFileToSendQueue(INT32 node, const char *filename, boolean textmode
 	strlcpy(p->id.filename, filename, MAX_WADPATH); // !!!
 	//nameonly(p->id.filename);
 
-	// Open in text mode if required by the Lua script
-	p->textmode = textmode;
-
 	DEBFILE(va("Sending Lua file %s to %d\n", filename, node));
 	p->ram = SF_FILE; // It's a file, we need to close it and free its name once we're done sending it
 	p->next = NULL; // End of list
@@ -937,7 +951,7 @@ void FileSendTicker(void)
 				long filesize;
 
 				transfer[i].currentfile =
-					fopen(f->id.filename, f->textmode ? "r" : "rb");
+					fopen(f->id.filename, "rb");
 
 				if (!transfer[i].currentfile)
 					I_Error("File %s does not exist",
@@ -984,18 +998,10 @@ void FileSendTicker(void)
 			M_Memcpy(p->data, &f->id.ram[transfer[i].position], fragmentsize);
 		else
 		{
-			size_t n;
-
 			fseek(transfer[i].currentfile, transfer[i].position, SEEK_SET);
 
-			n = fread(p->data, 1, fragmentsize, transfer[i].currentfile);
-			if (n != fragmentsize) // Either an error or Windows turning CR-LF into LF
-			{
-				if (f->textmode && feof(transfer[i].currentfile))
-                    fragmentsize = n;
-				else if (fread(p->data, 1, fragmentsize, transfer[i].currentfile) != fragmentsize)
-					I_Error("FileSendTicker: can't read %s byte on %s at %d because %s", sizeu1(fragmentsize), f->id.filename, transfer[i].position, M_FileError(transfer[i].currentfile));
-			}
+			if (fread(p->data, 1, fragmentsize, transfer[i].currentfile) != fragmentsize)
+				I_Error("FileSendTicker: can't read %s byte on %s at %d because %s", sizeu1(fragmentsize), f->id.filename, transfer[i].position, M_FileError(transfer[i].currentfile));
 		}
 		p->position = LONG(transfer[i].position);
 		p->fileid = f->fileid;
@@ -1195,7 +1201,7 @@ void PT_FileFragment(void)
 
 		if (CL_CanResumeDownload(file))
 		{
-			file->file = fopen(filename, file->textmode ? "r+" : "r+b");
+			file->file = fopen(filename, "r+b");
 			if (!file->file)
 				I_Error("Can't reopen file %s: %s", filename, strerror(errno));
 			CONS_Printf("\r%s...\n", filename);
@@ -1212,7 +1218,7 @@ void PT_FileFragment(void)
 		{
 			CL_AbortDownloadResume();
 
-			file->file = fopen(filename, file->textmode ? "w" : "wb");
+			file->file = fopen(filename, "wb");
 			if (!file->file)
 				I_Error("Can't create file %s: %s", filename, strerror(errno));
 
diff --git a/src/d_netfil.h b/src/d_netfil.h
index 171b3920f..dce2c929f 100644
--- a/src/d_netfil.h
+++ b/src/d_netfil.h
@@ -50,7 +50,6 @@ typedef struct
 	UINT32 ackresendposition; // Used when resuming downloads
 	filestatus_t status; // The value returned by recsearch
 	boolean justdownloaded; // To prevent late fragments from causing an I_Error
-	boolean textmode; // For files requested by Lua without the "b" option
 } fileneeded_t;
 
 extern INT32 fileneedednum;
@@ -105,9 +104,8 @@ extern boolean waitingforluafiletransfer;
 extern char luafiledir[256 + 16];
 
 void AddLuaFileTransfer(const char *filename, const char *mode);
-void SV_PrepareSendLuaFileToNextNode(void);
-boolean AddLuaFileToSendQueue(INT32 node, const char *filename, boolean textmode);
-void SV_PrepareSendLuaFile(const char *filename);
+void SV_PrepareSendLuaFile(void);
+boolean AddLuaFileToSendQueue(INT32 node, const char *filename);
 void SV_HandleLuaFileSent(UINT8 node);
 void RemoveLuaFileTransfer(void);
 void RemoveAllLuaFileTransfers(void);

From c8948909d37e1421d4faf7959ab9be29ec4277a4 Mon Sep 17 00:00:00 2001
From: Louis-Antoine <lamr@free.fr>
Date: Tue, 19 May 2020 23:50:37 +0200
Subject: [PATCH 09/12] Fix I_Error when queuing multiple Lua files

---
 src/blua/liolib.c |  6 ++++++
 src/d_clisrv.c    |  1 +
 src/d_netfil.c    | 13 +++++++++++++
 src/d_netfil.h    |  2 ++
 4 files changed, 22 insertions(+)

diff --git a/src/blua/liolib.c b/src/blua/liolib.c
index 2ccfa70e8..a055aad3f 100644
--- a/src/blua/liolib.c
+++ b/src/blua/liolib.c
@@ -321,6 +321,12 @@ void Got_LuaFile(UINT8 **cp, INT32 playernum)
 
 	RemoveLuaFileTransfer();
 
+	if (waitingforluafilecommand)
+	{
+		waitingforluafilecommand = false;
+		CL_PrepareDownloadLuaFile();
+	}
+
 	if (server && luafiletransfers)
 		SV_PrepareSendLuaFile();
 }
diff --git a/src/d_clisrv.c b/src/d_clisrv.c
index 275eb790e..dbf10d58e 100644
--- a/src/d_clisrv.c
+++ b/src/d_clisrv.c
@@ -3256,6 +3256,7 @@ void D_QuitNetGame(void)
 	CloseNetFile();
 	RemoveAllLuaFileTransfers();
 	waitingforluafiletransfer = false;
+	waitingforluafilecommand = false;
 
 	if (server)
 	{
diff --git a/src/d_netfil.c b/src/d_netfil.c
index da190bc5c..c5f3d8658 100644
--- a/src/d_netfil.c
+++ b/src/d_netfil.c
@@ -110,6 +110,7 @@ INT32 lastfilenum = -1;
 
 luafiletransfer_t *luafiletransfers = NULL;
 boolean waitingforluafiletransfer = false;
+boolean waitingforluafilecommand = false;
 char luafiledir[256 + 16] = "luafiles";
 
 
@@ -536,6 +537,8 @@ void AddLuaFileTransfer(const char *filename, const char *mode)
 	// Only if there is no transfer already going on
 	if (server && filetransfer == luafiletransfers)
 		SV_PrepareSendLuaFile();
+	else
+		filetransfer->ongoing = false;
 
 	// Store the callback so it can be called once everyone has the file
 	filetransfer->id = id;
@@ -578,6 +581,8 @@ void SV_PrepareSendLuaFile(void)
 	char *binfilename;
 	INT32 i;
 
+	luafiletransfers->ongoing = true;
+
 	// Set status to "waiting" for everyone
 	for (i = 0; i < MAXNETNODES; i++)
 		luafiletransfers->nodestatus[i] = LFTNS_WAITING;
@@ -660,6 +665,12 @@ void CL_PrepareDownloadLuaFile(void)
 		return;
 	}
 
+	if (luafiletransfers->ongoing)
+	{
+		waitingforluafilecommand = true;
+		return;
+	}
+
 	// Tell the server we are ready to receive the file
 	netbuffer->packettype = PT_ASKLUAFILE;
 	HSendPacket(servernode, true, 0, 0);
@@ -674,6 +685,8 @@ void CL_PrepareDownloadLuaFile(void)
 
 	// Make sure all directories in the file path exist
 	MakePathDirs(fileneeded[0].filename);
+
+	luafiletransfers->ongoing = true;
 }
 
 // Number of files to send
diff --git a/src/d_netfil.h b/src/d_netfil.h
index dce2c929f..be58f807f 100644
--- a/src/d_netfil.h
+++ b/src/d_netfil.h
@@ -95,12 +95,14 @@ typedef struct luafiletransfer_s
 	char *realfilename;
 	char mode[4]; // rb+/wb+/ab+ + null character
 	INT32 id; // Callback ID
+	boolean ongoing;
 	luafiletransfernodestatus_t nodestatus[MAXNETNODES];
 	struct luafiletransfer_s *next;
 } luafiletransfer_t;
 
 extern luafiletransfer_t *luafiletransfers;
 extern boolean waitingforluafiletransfer;
+extern boolean waitingforluafilecommand;
 extern char luafiledir[256 + 16];
 
 void AddLuaFileTransfer(const char *filename, const char *mode);

From 06060c02d38d174031e2d0fc1488f44920323611 Mon Sep 17 00:00:00 2001
From: Louis-Antoine <lamr@free.fr>
Date: Wed, 20 May 2020 00:24:53 +0200
Subject: [PATCH 10/12] Add a command to list current file transfers

---
 src/d_netcmd.c |  2 ++
 src/d_netfil.c | 34 ++++++++++++++++++++++++++++++++++
 src/d_netfil.h |  2 ++
 3 files changed, 38 insertions(+)

diff --git a/src/d_netcmd.c b/src/d_netcmd.c
index dfc7351f5..042b99cc7 100644
--- a/src/d_netcmd.c
+++ b/src/d_netcmd.c
@@ -501,6 +501,8 @@ void D_RegisterServerCommands(void)
 	COM_AddCommand("archivetest", Command_Archivetest_f);
 #endif
 
+	COM_AddCommand("downloads", Command_Downloads_f);
+
 	// for master server connection
 	AddMServCommands();
 
diff --git a/src/d_netfil.c b/src/d_netfil.c
index c5f3d8658..9e43da791 100644
--- a/src/d_netfil.c
+++ b/src/d_netfil.c
@@ -1386,6 +1386,40 @@ void CloseNetFile(void)
 		}
 }
 
+void Command_Downloads_f(void)
+{
+	INT32 node;
+
+	for (node = 0; node < MAXNETNODES; node++)
+		if (transfer[node].txlist
+		&& transfer[node].txlist->ram == SF_FILE) // Node is downloading a file?
+		{
+			const char *name = transfer[node].txlist->id.filename;
+			UINT32 position = transfer[node].position;
+			UINT32 size = transfer[node].txlist->size;
+			char ratecolor;
+
+			// Avoid division by zero errors
+			if (!size)
+				size = 1;
+
+			name = &name[strlen(name) - nameonlylength(name)];
+			switch (4 * (position - 1) / size)
+			{
+				case 0: ratecolor = '\x85'; break;
+				case 1: ratecolor = '\x87'; break;
+				case 2: ratecolor = '\x82'; break;
+				case 3: ratecolor = '\x83'; break;
+				default: ratecolor = '\x80';
+			}
+
+			CONS_Printf("%2d  %c%s  ", node, ratecolor, name); // Node and file name
+			CONS_Printf("\x80%uK\x84/\x80%uK ", position / 1024, size / 1024); // Progress in kB
+			CONS_Printf("\x80(%c%u%%\x80)  ", ratecolor, (UINT32)(100.0 * position / size)); // Progress in %
+			CONS_Printf("%s\n", I_GetNodeAddress(node)); // Address and newline
+		}
+}
+
 // Functions cut and pasted from Doomatic :)
 
 void nameonly(char *s)
diff --git a/src/d_netfil.h b/src/d_netfil.h
index be58f807f..a653d5a4b 100644
--- a/src/d_netfil.h
+++ b/src/d_netfil.h
@@ -122,6 +122,8 @@ void SV_AbortSendFiles(INT32 node);
 void CloseNetFile(void);
 void CL_AbortDownloadResume(void);
 
+void Command_Downloads_f(void);
+
 boolean fileexist(char *filename, time_t ptime);
 
 // Search a file in the wadpath, return FS_FOUND when found

From bf00955786cf0628afb2639915ba1a1c8bf69eba Mon Sep 17 00:00:00 2001
From: Louis-Antoine <lamr@free.fr>
Date: Wed, 20 May 2020 16:21:18 +0200
Subject: [PATCH 11/12] Wait for acks before resending file fragments

---
 src/d_clisrv.h |  2 ++
 src/d_netfil.c | 46 ++++++++++++++++++++++++++++++++++++++++++----
 src/d_netfil.h |  6 ++++--
 3 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/src/d_clisrv.h b/src/d_clisrv.h
index cbae55017..c8241fede 100644
--- a/src/d_clisrv.h
+++ b/src/d_clisrv.h
@@ -326,6 +326,7 @@ typedef struct
 {
 	UINT8 fileid;
 	UINT32 filesize;
+	UINT8 iteration;
 	UINT32 position;
 	UINT16 size;
 	UINT8 data[0]; // Size is variable using hardware_MAXPACKETLENGTH
@@ -340,6 +341,7 @@ typedef struct
 typedef struct
 {
 	UINT8 fileid;
+	UINT8 iteration;
 	UINT8 numsegments;
 	fileacksegment_t segments[0];
 } ATTRPACK fileack_pak;
diff --git a/src/d_netfil.c b/src/d_netfil.c
index 9e43da791..560e4d334 100644
--- a/src/d_netfil.c
+++ b/src/d_netfil.c
@@ -76,10 +76,13 @@ typedef struct filetx_s
 typedef struct filetran_s
 {
 	filetx_t *txlist; // Linked list of all files for the node
+	UINT8 iteration;
+	UINT8 ackediteration;
 	UINT32 position; // The current position in the file
 	boolean *ackedfragments;
 	UINT32 ackedsize;
 	FILE *currentfile; // The file currently being sent/received
+	tic_t dontsenduntil;
 } filetran_t;
 static filetran_t transfer[MAXNETNODES];
 
@@ -986,20 +989,36 @@ void FileSendTicker(void)
 			else // Sending RAM
 				transfer[i].currentfile = (FILE *)1; // Set currentfile to a non-null value to indicate that it is open
 
+			transfer[i].iteration = 1;
+			transfer[i].ackediteration = 0;
 			transfer[i].position = 0;
 			transfer[i].ackedsize = 0;
 
 			transfer[i].ackedfragments = calloc(f->size / FILEFRAGMENTSIZE + 1, sizeof(*transfer[i].ackedfragments));
 			if (!transfer[i].ackedfragments)
 				I_Error("FileSendTicker: No more memory\n");
+
+			transfer[i].dontsenduntil = 0;
 		}
 
+		// If the client hasn't acknowledged any fragment from the previous iteration,
+		// it is most likely because their acks haven't had enough time to reach the server
+		// yet, due to latency. In that case, we wait a little to avoid useless resend.
+		if (I_GetTime() < transfer[i].dontsenduntil)
+			continue;
+
 		// Find the first non-acknowledged fragment
 		while (transfer[i].ackedfragments[transfer[i].position / FILEFRAGMENTSIZE])
 		{
 			transfer[i].position += FILEFRAGMENTSIZE;
 			if (transfer[i].position >= f->size)
+			{
+				if (transfer[i].ackediteration < transfer[i].iteration)
+					transfer[i].dontsenduntil = I_GetTime() + TICRATE / 2;
+
 				transfer[i].position = 0;
+				transfer[i].iteration++;
+			}
 		}
 
 		// Build a packet containing a file fragment
@@ -1016,6 +1035,7 @@ void FileSendTicker(void)
 			if (fread(p->data, 1, fragmentsize, transfer[i].currentfile) != fragmentsize)
 				I_Error("FileSendTicker: can't read %s byte on %s at %d because %s", sizeu1(fragmentsize), f->id.filename, transfer[i].position, M_FileError(transfer[i].currentfile));
 		}
+		p->iteration = transfer[i].iteration;
 		p->position = LONG(transfer[i].position);
 		p->fileid = f->fileid;
 		p->filesize = LONG(f->size);
@@ -1026,7 +1046,13 @@ void FileSendTicker(void)
 		{ // Success
 			transfer[i].position = (UINT32)(transfer[i].position + fragmentsize);
 			if (transfer[i].position >= f->size)
+			{
+				if (transfer[i].ackediteration < transfer[i].iteration)
+					transfer[i].dontsenduntil = I_GetTime() + TICRATE / 2;
+
 				transfer[i].position = 0;
+				transfer[i].iteration++;
+			}
 		}
 		else
 		{ // Not sent for some odd reason, retry at next call
@@ -1053,6 +1079,13 @@ void PT_FileAck(void)
 		return;
 	}
 
+	if (packet->iteration > trans->ackediteration)
+	{
+		trans->ackediteration = packet->iteration;
+		if (trans->ackediteration >= trans->iteration - 1)
+			trans->dontsenduntil = 0;
+	}
+
 	for (i = 0; i < packet->numsegments; i++)
 	{
 		fileacksegment_t *segment = &packet->segments[i];
@@ -1114,10 +1147,12 @@ static void SendAckPacket(fileack_pak *packet, UINT8 fileid)
 	memset(packet, 0, sizeof(*packet) + 512);
 }
 
-static void AddFragmentToAckPacket(fileack_pak *packet, UINT32 fragmentpos, UINT8 fileid)
+static void AddFragmentToAckPacket(fileack_pak *packet, UINT8 iteration, UINT32 fragmentpos, UINT8 fileid)
 {
 	fileacksegment_t *segment = &packet->segments[packet->numsegments - 1];
 
+	packet->iteration = max(packet->iteration, iteration);
+
     if (packet->numsegments == 0
 		|| fragmentpos < segment->start
 		|| fragmentpos - segment->start >= 32)
@@ -1157,7 +1192,7 @@ void FileReceiveTicker(void)
 				for (j = 0; j < 2048; j++)
 				{
 					if (file->receivedfragments[file->ackresendposition])
-						AddFragmentToAckPacket(file->ackpacket, file->ackresendposition, i);
+						AddFragmentToAckPacket(file->ackpacket, file->iteration, file->ackresendposition, i);
 
 					file->ackresendposition++;
 					if (file->ackresendposition * file->fragmentsize >= file->totalsize)
@@ -1207,6 +1242,7 @@ void PT_FileFragment(void)
 
 		file->status = FS_DOWNLOADING;
 		file->fragmentsize = fragmentsize;
+		file->iteration = 0;
 
 		file->ackpacket = calloc(1, sizeof(*file->ackpacket) + 512);
 		if (!file->ackpacket)
@@ -1254,6 +1290,8 @@ void PT_FileFragment(void)
 		if (fragmentpos >= file->totalsize)
 			I_Error("Invalid file fragment\n");
 
+		file->iteration = max(file->iteration, netbuffer->u.filetxpak.iteration);
+
 		if (!file->receivedfragments[fragmentpos / fragmentsize]) // Not received yet
 		{
 			file->receivedfragments[fragmentpos / fragmentsize] = true;
@@ -1264,7 +1302,7 @@ void PT_FileFragment(void)
 				I_Error("Can't write to %s: %s\n",filename, M_FileError(file->file));
 			file->currentsize += boundedfragmentsize;
 
-			AddFragmentToAckPacket(file->ackpacket, fragmentpos / fragmentsize, filenum);
+			AddFragmentToAckPacket(file->ackpacket, file->iteration, fragmentpos / fragmentsize, filenum);
 
 			// Finished?
 			if (file->currentsize == file->totalsize)
@@ -1295,7 +1333,7 @@ void PT_FileFragment(void)
 		{
 			// If they are sending us the fragment again, it's probably because
 			// they missed our previous ack, so we must re-acknowledge it
-			AddFragmentToAckPacket(file->ackpacket, fragmentpos / fragmentsize, filenum);
+			AddFragmentToAckPacket(file->ackpacket, file->iteration, fragmentpos / fragmentsize, filenum);
 		}
 	}
 	else if (!file->justdownloaded)
diff --git a/src/d_netfil.h b/src/d_netfil.h
index a653d5a4b..2225157cb 100644
--- a/src/d_netfil.h
+++ b/src/d_netfil.h
@@ -40,16 +40,18 @@ typedef struct
 	UINT8 willsend; // Is the server willing to send it?
 	char filename[MAX_WADPATH];
 	UINT8 md5sum[16];
+	filestatus_t status; // The value returned by recsearch
+	boolean justdownloaded; // To prevent late fragments from causing an I_Error
+
 	// Used only for download
 	FILE *file;
 	boolean *receivedfragments;
 	UINT32 fragmentsize;
+	UINT8 iteration;
 	fileack_pak *ackpacket;
 	UINT32 currentsize;
 	UINT32 totalsize;
 	UINT32 ackresendposition; // Used when resuming downloads
-	filestatus_t status; // The value returned by recsearch
-	boolean justdownloaded; // To prevent late fragments from causing an I_Error
 } fileneeded_t;
 
 extern INT32 fileneedednum;

From 3c3a60d189981920f9b0837a4db24a3488ac9f53 Mon Sep 17 00:00:00 2001
From: Louis-Antoine <lamr@free.fr>
Date: Mon, 1 Jun 2020 10:37:05 +0200
Subject: [PATCH 12/12] Fix "downloads" command reporting incorrect progress

---
 src/d_netfil.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/d_netfil.c b/src/d_netfil.c
index 560e4d334..7b99fddfb 100644
--- a/src/d_netfil.c
+++ b/src/d_netfil.c
@@ -1433,7 +1433,7 @@ void Command_Downloads_f(void)
 		&& transfer[node].txlist->ram == SF_FILE) // Node is downloading a file?
 		{
 			const char *name = transfer[node].txlist->id.filename;
-			UINT32 position = transfer[node].position;
+			UINT32 position = transfer[node].ackedsize;
 			UINT32 size = transfer[node].txlist->size;
 			char ratecolor;