Initial implementation of DOSBox encapsulation support.

Incomplete and completely untested at this point, beyond "it compiles".

src/interface.c

@@ -29,13 +29,20 @@
 
 #define INTERFACE_CACHE_TTL 5
 
-BOOL ipx_use_pcap;
+enum main_config_encap_type ipx_encap_type;
+
+enum dosbox_state dosbox_state = DOSBOX_DISCONNECTED;
+
+addr32_t dosbox_local_netnum;
+addr48_t dosbox_local_nodenum;
 
 static CRITICAL_SECTION interface_cache_cs;
 
 static ipx_interface_t *interface_cache = NULL;
 static time_t interface_cache_ctime = 0;
 
+static void renew_interface_cache(bool force);
+
 /* Fetch a list of network interfaces available on the system.
  *
  * Returns a linked list of IP_ADAPTER_INFO structures, all allocated within a
@@ -465,11 +472,12 @@ void ipx_interfaces_init(void)
 	
 	log_printf(LOG_INFO, "--");
 	
-	if(ipx_use_pcap)
+	if(ipx_encap_type == ENCAP_TYPE_PCAP)
 	{
 		_init_pcap_interfaces();
 	}
-	else{
+	else if(ipx_encap_type == ENCAP_TYPE_IPXWRAPPER)
+	{
 		/* IP interfaces... */
 		
 		IP_ADAPTER_INFO *ip_ifaces = load_sys_interfaces(), *ip;
@@ -559,7 +567,7 @@ void ipx_interfaces_cleanup(void)
 {
 	DeleteCriticalSection(&interface_cache_cs);
 	
-	if(ipx_use_pcap)
+	if(ipx_encap_type == ENCAP_TYPE_PCAP)
 	{
 		for(ipx_interface_t *i = interface_cache; i; i = i->next)
 		{
@@ -570,12 +578,18 @@ void ipx_interfaces_cleanup(void)
 	free_ipx_interface_list(&interface_cache);
 }
 
+/* Flush and repopulate the interface cache. */
+void ipx_interfaces_reload(void)
+{
+	renew_interface_cache(true);
+}
+
 /* Check the age of the IPX interface cache and reload it if necessary.
  * Ensure you hold interface_cache_cs before calling.
 */
-static void renew_interface_cache(void)
+static void renew_interface_cache(bool force)
 {
-	if(ipx_use_pcap)
+	if(ipx_encap_type == ENCAP_TYPE_PCAP)
 	{
 		/* interface_cache is initialised during init when pcap is in
 		 * use and survives for the lifetime of the program.
@@ -583,11 +597,18 @@ static void renew_interface_cache(void)
 		return;
 	}
 	
-	if(time(NULL) - interface_cache_ctime > INTERFACE_CACHE_TTL)
+	if(force || time(NULL) - interface_cache_ctime > INTERFACE_CACHE_TTL)
 	{
 		free_ipx_interface_list(&interface_cache);
 		
-		interface_cache       = load_ipx_interfaces();
+		if(ipx_encap_type == ENCAP_TYPE_DOSBOX)
+		{
+			interface_cache = load_dosbox_interfaces();
+		}
+		else{
+			interface_cache = load_ipx_interfaces();
+		}
+		
 		interface_cache_ctime = time(NULL);
 	}
 }
@@ -599,7 +620,7 @@ ipx_interface_t *get_ipx_interfaces(void)
 {
 	EnterCriticalSection(&interface_cache_cs);
 	
-	renew_interface_cache();
+	renew_interface_cache(false);
 	
 	ipx_interface_t *copy = copy_ipx_interface_list(interface_cache);
 	
@@ -615,7 +636,7 @@ ipx_interface_t *ipx_interface_by_addr(addr32_t net, addr48_t node)
 {
 	EnterCriticalSection(&interface_cache_cs);
 	
-	renew_interface_cache();
+	renew_interface_cache(false);
 	
 	ipx_interface_t *iface;
 	
@@ -640,7 +661,7 @@ ipx_interface_t *ipx_interface_by_subnet(uint32_t ipaddr)
 {
 	EnterCriticalSection(&interface_cache_cs);
 	
-	renew_interface_cache();
+	renew_interface_cache(false);
 	
 	ipx_interface_t *iface;
 	
@@ -671,7 +692,7 @@ ipx_interface_t *ipx_interface_by_index(int index)
 {
 	EnterCriticalSection(&interface_cache_cs);
 	
-	renew_interface_cache();
+	renew_interface_cache(false);
 	
 	int iface_index = 0;
 	ipx_interface_t *iface;
@@ -695,7 +716,7 @@ int ipx_interface_count(void)
 {
 	EnterCriticalSection(&interface_cache_cs);
 	
-	renew_interface_cache();
+	renew_interface_cache(false);
 	
 	int count = 0;
 	ipx_interface_t *iface;
@@ -807,3 +828,19 @@ void ipx_free_pcap_interfaces(ipx_pcap_interface_t **interfaces)
 		free(p);
 	}
 }
+
+ipx_interface_t *load_dosbox_interfaces(void)
+{
+	ipx_interface_t *nics = NULL;
+	
+	if(dosbox_state == DOSBOX_CONNECTED)
+	{
+		ipx_interface_t *dosbox_iface = _new_iface(dosbox_local_netnum, dosbox_local_nodenum);
+		if(dosbox_iface)
+		{
+			DL_APPEND(nics, dosbox_iface);
+		}
+	}
+	
+	return nics;
+}

src/interface.h

@@ -1,5 +1,5 @@
 /* IPXWrapper - Interface header
- * Copyright (C) 2011 Daniel Collins <solemnwarning@solemnwarning.net>
+ * Copyright (C) 2011-2021 Daniel Collins <solemnwarning@solemnwarning.net>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published by
@@ -23,6 +23,7 @@
 #include <utlist.h>
 #include <pcap.h>
 
+#include "config.h"
 #include "common.h"
 
 #ifdef __cplusplus
@@ -75,7 +76,19 @@ struct ipx_pcap_interface {
 	ipx_pcap_interface_t *next;
 };
 
-extern BOOL ipx_use_pcap;
+extern enum main_config_encap_type ipx_encap_type;
+
+enum dosbox_state
+{
+	DOSBOX_DISCONNECTED,
+	DOSBOX_RESOLVING,
+	DOSBOX_REGISTERING,
+	DOSBOX_CONNECTED,
+};
+
+extern enum dosbox_state dosbox_state;
+extern addr32_t dosbox_local_netnum;
+extern addr48_t dosbox_local_nodenum;
 
 IP_ADAPTER_INFO *load_sys_interfaces(void);
 ipx_interface_t *load_ipx_interfaces(void);
@@ -88,6 +101,7 @@ void free_ipx_interface_list(ipx_interface_t **list);
 
 void ipx_interfaces_init(void);
 void ipx_interfaces_cleanup(void);
+void ipx_interfaces_reload(void);
 
 ipx_interface_t *get_ipx_interfaces(void);
 ipx_interface_t *ipx_interface_by_addr(addr32_t net, addr48_t node);
@@ -98,6 +112,8 @@ int ipx_interface_count(void);
 ipx_pcap_interface_t *ipx_get_pcap_interfaces(void);
 void ipx_free_pcap_interfaces(ipx_pcap_interface_t **interfaces);
 
+ipx_interface_t *load_dosbox_interfaces(void);
+
 #ifdef __cplusplus
 }
 #endif

src/ipxwrapper.c

@@ -81,7 +81,7 @@ BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
 		
 		main_config = get_main_config();
 		min_log_level = main_config.log_level;
-		ipx_use_pcap  = main_config.encap_type == ENCAP_TYPE_PCAP;
+		ipx_encap_type = main_config.encap_type;
 		
 		if(main_config.fw_except)
 		{

src/router.c

@@ -1,5 +1,5 @@
 /* IPXWrapper - Router code
- * Copyright (C) 2011 Daniel Collins <solemnwarning@solemnwarning.net>
+ * Copyright (C) 2011-2021 Daniel Collins <solemnwarning@solemnwarning.net>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published by
@@ -38,23 +38,32 @@ static HANDLE router_thread  = NULL;
 /* The shared socket uses the UDP port number specified in the configuration,
  * every IPXWrapper instance will share it and use it to receive broadcast
  * packets.
- * 
+ *
  * The private socket uses a randomly allocated UDP port number and is used to
  * send packets and receive unicast, it is unique to a single IPXWrapper
  * instance.
- * 
+ *
  * When running in WinPcap mode, only the private socket will be opened and it
  * will be bound to loopback rather than INADDR_ANY since it is only used for
  * forwarding IPX packets on to local sockets.
+ *
+ * When running in DOSBox mode, only the private socket will be opened and it
+ * will be "connected" to the DOSBox server address.
 */
 
 SOCKET shared_socket  = -1;
 SOCKET private_socket = -1;
 
+#define DOSBOX_CONNECT_TIMEOUT_SECS 10
+
+static struct sockaddr_in dosbox_server_addr;
+static time_t dosbox_connect_begin;
+
+static void _send_dosbox_registration_request(void);
 static DWORD router_main(void *arg);
 
 /* Initialise a UDP socket. */
-static void _init_socket(SOCKET *sock, uint16_t port, BOOL reuseaddr)
+static void _init_socket(SOCKET *sock, uint16_t port, BOOL broadcast, BOOL reuseaddr)
 {
 	/* Socket used for sending and receiving packets on the network. */
 	
@@ -66,8 +75,6 @@ static void _init_socket(SOCKET *sock, uint16_t port, BOOL reuseaddr)
 	
 	/* Enable broadcast and address reuse. */
 	
-	BOOL broadcast = TRUE;
-	
 	setsockopt(*sock, SOL_SOCKET, SO_BROADCAST, (char*)&broadcast, sizeof(BOOL));
 	setsockopt(*sock, SOL_SOCKET, SO_REUSEADDR, (char*)&reuseaddr, sizeof(BOOL));
 	
@@ -110,7 +117,7 @@ void router_init(void)
 		abort();
 	}
 	
-	if(ipx_use_pcap)
+	if(ipx_encap_type == ENCAP_TYPE_PCAP)
 	{
 		if((private_socket = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
 		{
@@ -129,9 +136,29 @@ void router_init(void)
 			abort();
 		}
 	}
+	else if(ipx_encap_type == ENCAP_TYPE_DOSBOX)
+	{
+		/* TODO: Support DNS. Do this async somewhere within router_main. */
+		
+		dosbox_server_addr.sin_family = AF_INET;
+		dosbox_server_addr.sin_addr.s_addr = inet_addr(main_config.dosbox_server_addr);
+		dosbox_server_addr.sin_port = htons(main_config.dosbox_server_port);
+		
+		if(connect(private_socket, (struct sockaddr*)(&dosbox_server_addr), sizeof(dosbox_server_addr)) != 0)
+		{
+			log_printf(LOG_ERROR, "Error connecting private socket: %s", w32_error(WSAGetLastError()));
+			abort();
+		}
+		
+		_send_dosbox_registration_request();
+		
+		dosbox_state = DOSBOX_REGISTERING;
+		
+		_init_socket(&private_socket, 0, FALSE, FALSE);
+	}
 	else{
-		_init_socket(&shared_socket, main_config.udp_port, TRUE);
+		_init_socket(&shared_socket, main_config.udp_port, TRUE, TRUE);
-		_init_socket(&private_socket, 0, FALSE);
+		_init_socket(&private_socket, 0, TRUE, FALSE);
 	}
 	
 	router_running = true;
@@ -472,6 +499,68 @@ static void _handle_udp_recv(ipx_packet *packet, size_t packet_size, struct sock
 		data_size);
 }
 
+static void _handle_dosbox_registration_response(novell_ipx_packet *packet, size_t packet_size)
+{
+	if(packet_size < sizeof(novell_ipx_packet)
+		|| ntohs(packet->length) != packet_size
+		|| ntohs(packet->checksum) != 0xFFFF
+		|| ntohs(packet->type) != 2)
+	{
+		/* Doesn't look valid. */
+		log_printf(LOG_ERROR, "Got invalid registration response from DOSBox server!");
+		abort();
+	}
+	
+	dosbox_local_netnum  = addr32_in(packet->dest_net);
+	dosbox_local_nodenum = addr48_in(packet->dest_node);
+	
+	dosbox_state = DOSBOX_CONNECTED;
+	
+	ipx_interfaces_reload();
+	
+	char local_netnum_s[ADDR32_STRING_SIZE];
+	addr32_string(local_netnum_s, dosbox_local_netnum);
+	
+	char local_nodenum_s[ADDR48_STRING_SIZE];
+	addr48_string(local_nodenum_s, dosbox_local_nodenum);
+	
+	log_printf(LOG_INFO, "Connected to DOSBox server, local address: %s/%s", local_netnum_s, local_nodenum_s);
+}
+
+static void _handle_dosbox_recv(novell_ipx_packet *packet, size_t packet_size)
+{
+	if(packet_size < sizeof(novell_ipx_packet) || ntohs(packet->length) != packet_size)
+	{
+		/* Doesn't look valid. */
+		log_printf(LOG_ERROR, "Recieved invalid IPX packet from DOSBox server, dropping");
+		return;
+	}
+	
+	if(min_log_level <= LOG_DEBUG)
+	{
+		IPX_STRING_ADDR(src_addr, addr32_in(packet->src_net), addr48_in(packet->src_node), packet->src_socket);
+		IPX_STRING_ADDR(dest_addr, addr32_in(packet->dest_net), addr48_in(packet->dest_node), packet->dest_socket);
+		
+		log_printf(LOG_DEBUG, "Recieved packet from %s for %s", src_addr, dest_addr);
+	}
+	
+	size_t data_size = ntohs(packet->length) - sizeof(novell_ipx_packet);
+	
+	_deliver_packet(
+		packet->type,
+		
+		addr32_in(packet->src_net),
+		addr48_in(packet->src_node),
+		packet->src_socket,
+		
+		addr32_in(packet->dest_net),
+		addr48_in(packet->dest_node),
+		packet->dest_socket,
+		
+		packet->data,
+		data_size);
+}
+
 static bool _do_udp_recv(int fd)
 {
 	struct sockaddr_in addr;
@@ -489,7 +578,24 @@ static bool _do_udp_recv(int fd)
 		return false;
 	}
 	
-	_handle_udp_recv((ipx_packet*)(buf), len, addr);
+	if(ipx_encap_type == ENCAP_TYPE_DOSBOX)
+	{
+		if(dosbox_state == DOSBOX_REGISTERING)
+		{
+			_handle_dosbox_registration_response((novell_ipx_packet*)(buf), len);
+		}
+		else if(dosbox_state == DOSBOX_CONNECTED)
+		{
+			_handle_dosbox_recv((novell_ipx_packet*)(buf), len);
+		}
+		else{
+			/* Unreachable. */
+			abort();
+		}
+	}
+	else{
+		_handle_udp_recv((ipx_packet*)(buf), len, addr);
+	}
 	
 	return true;
 }
@@ -566,6 +672,29 @@ static void _handle_pcap_frame(u_char *user, const struct pcap_pkthdr *pkt_heade
 		(ntohs(ipx->length) - sizeof(novell_ipx_packet)));
 }
 
+static void _send_dosbox_registration_request(void)
+{
+	novell_ipx_packet reg_pkt;
+	
+	reg_pkt.checksum = 0xFFFF;
+	reg_pkt.length = htons(sizeof(novell_ipx_packet));
+	reg_pkt.hops = 0;
+	reg_pkt.type = 2;
+	
+	memset(reg_pkt.dest_net, 0, sizeof(reg_pkt.dest_net));
+	memset(reg_pkt.dest_node, 0, sizeof(reg_pkt.dest_node));
+	reg_pkt.dest_socket = 0;
+	
+	memset(reg_pkt.src_net, 0, sizeof(reg_pkt.src_net));
+	memset(reg_pkt.src_node, 0, sizeof(reg_pkt.src_node));
+	reg_pkt.src_socket = 0;
+	
+	if(send(private_socket, (const void*)(&reg_pkt), sizeof(reg_pkt), 0) < 0)
+	{
+		log_printf(LOG_ERROR, "Error sending DOSBox IPX registration request: %s", w32_error(WSAGetLastError()));
+	}
+}
+
 static DWORD router_main(void *arg)
 {
 	DWORD exit_status = 0;
@@ -575,7 +704,7 @@ static DWORD router_main(void *arg)
 	HANDLE *wait_events = &router_event;
 	int n_events = 1;
 	
-	if(ipx_use_pcap)
+	if(ipx_encap_type == ENCAP_TYPE_PCAP)
 	{
 		interfaces = get_ipx_interfaces();
 		ipx_interface_t *i;
@@ -613,7 +742,7 @@ static DWORD router_main(void *arg)
 			break;
 		}
 		
-		if(ipx_use_pcap)
+		if(ipx_encap_type == ENCAP_TYPE_PCAP)
 		{
 			ipx_interface_t *i;
 			DL_FOREACH(interfaces, i)
@@ -628,6 +757,14 @@ static DWORD router_main(void *arg)
 				}
 			}
 		}
+		else if(ipx_encap_type == ENCAP_TYPE_DOSBOX)
+		{
+			if(!_do_udp_recv(private_socket))
+			{
+				exit_status = 1;
+				break;
+			}
+		}
 		else{
 			if(!_do_udp_recv(shared_socket) || !_do_udp_recv(private_socket))
 			{
@@ -637,7 +774,7 @@ static DWORD router_main(void *arg)
 		}
 	}
 	
-	if(ipx_use_pcap)
+	if(ipx_encap_type == ENCAP_TYPE_PCAP)
 	{
 		free(wait_events);
 		free_ipx_interface_list(&interfaces);

src/winsock.c

@@ -1,5 +1,5 @@
 /* ipxwrapper - Winsock functions
- * Copyright (C) 2008-2014 Daniel Collins <solemnwarning@solemnwarning.net>
+ * Copyright (C) 2008-2021 Daniel Collins <solemnwarning@solemnwarning.net>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published by
@@ -50,7 +50,7 @@ static size_t strsize(void *str, bool unicode)
 
 static int _max_ipx_payload(void)
 {
-	if(ipx_use_pcap)
+	if(ipx_encap_type == ENCAP_TYPE_PCAP)
 	{
 		/* TODO: Use real interface MTU */
 		
@@ -66,6 +66,11 @@ static int _max_ipx_payload(void)
 		
 		abort();
 	}
+	else if(ipx_encap_type == ENCAP_TYPE_DOSBOX)
+	{
+		// TODO: DOXBox MTU
+		return 1500;
+	}
 	else{
 		return MAX_DATA_SIZE;
 	}
@@ -331,13 +336,20 @@ SOCKET WSAAPI socket(int af, int type, int protocol)
 		}
 		else if(type == SOCK_STREAM)
 		{
-			if(ipx_use_pcap)
+			if(ipx_encap_type == ENCAP_TYPE_PCAP)
 			{
 				log_printf(LOG_WARNING, "Application attempted to create an SPX socket, this isn't supported when using Ethernet encapsulation");
 				
 				WSASetLastError(WSAEPROTONOSUPPORT);
 				return -1;
 			}
+			else if(ipx_encap_type == ENCAP_TYPE_DOSBOX)
+			{
+				log_printf(LOG_WARNING, "Application attempted to create an SPX socket, this isn't supported when using DOSBox encapsulation");
+				
+				WSASetLastError(WSAEPROTONOSUPPORT);
+				return -1;
+			}
 			
 			if(protocol != 0 && protocol != NSPROTO_SPX && protocol != NSPROTO_SPXII)
 			{
@@ -1210,7 +1222,7 @@ static DWORD ipx_send_packet(
 			(unsigned int)(data_size), src_addr, dest_addr);
 	}
 	
-	if(ipx_use_pcap)
+	if(ipx_encap_type == ENCAP_TYPE_PCAP)
 	{
 		ipx_interface_t *iface = ipx_interface_by_addr(src_net, src_node);
 		if(iface)
@@ -1303,6 +1315,53 @@ static DWORD ipx_send_packet(
 			return WSAENETDOWN;
 		}
 	}
+	else if(ipx_encap_type == ENCAP_TYPE_DOSBOX)
+	{
+		if(dosbox_state != DOSBOX_CONNECTED)
+		{
+			return WSAENETDOWN;
+		}
+		else if(src_net != dosbox_local_netnum || src_node != dosbox_local_nodenum)
+		{
+			return WSAENETDOWN;
+		}
+		else{
+			size_t packet_size = sizeof(novell_ipx_packet) + data_size;
+			
+			novell_ipx_packet *packet = malloc(packet_size);
+			if(packet == NULL)
+			{
+				return ERROR_OUTOFMEMORY;
+			}
+			
+			packet->checksum = 0xFFFF;
+			packet->length = htons(sizeof(novell_ipx_packet) + data_size);
+			packet->hops = 0;
+			packet->type = type;
+			
+			addr32_out(packet->dest_net, dest_net);
+			addr48_out(packet->dest_node, dest_node);
+			packet->dest_socket = dest_socket;
+			
+			addr32_out(packet->src_net, src_net);
+			addr48_out(packet->src_node, src_node);
+			packet->src_socket = src_socket;
+			
+			memcpy(packet->data, data, data_size);
+			
+			DWORD error = ERROR_SUCCESS;
+			
+			if(r_send(private_socket, (const void*)(packet), packet_size, 0) < 0)
+			{
+				error = WSAGetLastError();
+				log_printf(LOG_ERROR, "Error sending DOSBox IPX packet: %s", w32_error(error));
+			}
+			
+			free(packet);
+			
+			return error;
+		}
+	}
 	else{
 		int packet_size = sizeof(ipx_packet) - 1 + data_size;