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-rw-r--r--src/engine/e_network.c937
1 files changed, 937 insertions, 0 deletions
diff --git a/src/engine/e_network.c b/src/engine/e_network.c
new file mode 100644
index 00000000..b26e75f0
--- /dev/null
+++ b/src/engine/e_network.c
@@ -0,0 +1,937 @@
+/* copyright (c) 2007 magnus auvinen, see licence.txt for more info */
+#include <string.h>
+#include <stdio.h>
+
+#include "e_system.h"
+#include "e_config.h"
+#include "e_network.h"
+
+/*
+	header (6 bytes)
+		unsigned char flags;		1
+		unsigned char seq_ack[3];	4
+		unsigned char token[2];		6
+*/
+
+enum
+{
+	NETWORK_VERSION = 1,
+	
+	NETWORK_HEADER_SIZE = 6,
+	NETWORK_MAX_PAYLOAD = 1024,
+	NETWORK_MAX_PACKET_SIZE = NETWORK_HEADER_SIZE+NETWORK_MAX_PAYLOAD,
+	NETWORK_MAX_CLIENTS = 16,
+	
+	NETWORK_CONNSTATE_OFFLINE=0,
+	NETWORK_CONNSTATE_CONNECT=1,
+	NETWORK_CONNSTATE_CONNECTACCEPTED=2,
+	NETWORK_CONNSTATE_ONLINE=3,
+	NETWORK_CONNSTATE_ERROR=4,
+	
+	NETWORK_PACKETFLAG_CONNECT=0x01,
+	NETWORK_PACKETFLAG_ACCEPT=0x02,
+	NETWORK_PACKETFLAG_CLOSE=0x04,
+	NETWORK_PACKETFLAG_VITAL=0x08,
+	NETWORK_PACKETFLAG_RESEND=0x10,
+	NETWORK_PACKETFLAG_CONNLESS=0x20,
+	
+	NETWORK_MAX_SEQACK=0x1000
+};
+
+static int current_token = 1;
+
+typedef struct
+{
+	unsigned char ID[2];
+	unsigned char version;
+	unsigned char flags;
+	unsigned short seq;
+	unsigned short ack;
+	unsigned crc;
+	int token;
+	unsigned data_size;
+	int64 first_send_time;
+	unsigned char *data;
+} NETPACKETDATA;
+
+
+static void send_packet(NETSOCKET socket, NETADDR4 *addr, NETPACKETDATA *packet)
+{
+	unsigned char buffer[NETWORK_MAX_PACKET_SIZE];
+	int send_size = NETWORK_HEADER_SIZE+packet->data_size;
+
+	buffer[0] = packet->flags;
+	buffer[1] = ((packet->seq>>4)&0xf0) | ((packet->ack>>8)&0x0f);
+	buffer[2] = packet->seq;
+	buffer[3] = packet->ack;
+	buffer[4] = packet->token>>8;
+	buffer[5] = packet->token&0xff;
+	mem_copy(buffer+NETWORK_HEADER_SIZE, packet->data, packet->data_size);
+	net_udp4_send(socket, addr, buffer, send_size);
+}
+
+typedef struct RINGBUFFER_ITEM_t
+{
+	struct RINGBUFFER_ITEM_t *next;
+	struct RINGBUFFER_ITEM_t *prev;
+	int size;
+} RINGBUFFER_ITEM;
+
+typedef struct
+{
+	RINGBUFFER_ITEM *first;
+	RINGBUFFER_ITEM *last;
+	unsigned buffer_size;
+} RINGBUFFER;
+
+static void rb_init(RINGBUFFER *rb)
+{
+	rb->first = 0;
+	rb->last = 0;
+	rb->buffer_size = 0;
+}
+
+static void *rb_item_data(RINGBUFFER_ITEM *item)
+{
+	return (void*)(item+1);
+}
+
+static void *rb_alloc(RINGBUFFER *rb, int size)
+{
+	RINGBUFFER_ITEM *item = (RINGBUFFER_ITEM*)mem_alloc(sizeof(RINGBUFFER_ITEM)+size, 1);
+	item->size = size;
+	
+	item->prev = rb->last;
+	item->next = 0;
+	if(rb->last)
+		rb->last->next = item;
+	else
+		rb->first = item;
+	rb->last = item;
+	
+	rb->buffer_size += size;
+	return rb_item_data(item);
+}
+
+static void rb_pop_first(RINGBUFFER *rb)
+{
+	if(rb->first)
+	{
+		RINGBUFFER_ITEM *next = rb->first->next;
+		rb->buffer_size -= rb->first->size;
+		mem_free(rb->first);
+		rb->first = next;
+		if(rb->first)
+			rb->first->prev = NULL;
+		else
+			rb->last = NULL;
+	}
+}
+
+static void rb_clear(RINGBUFFER *rb)
+{
+	while(rb->first)
+		rb_pop_first(rb);
+}
+
+
+typedef struct
+{
+	unsigned short seq;
+	unsigned short ack;
+	unsigned state;
+	
+	int token;
+	
+	int remote_closed;
+	
+	int connected;
+	int disconnected;
+	
+	RINGBUFFER buffer;
+	
+	int64 last_update_time;
+	int64 last_recv_time;
+	int64 last_send_time;
+	
+	char error_string[256];
+	
+	NETADDR4 peeraddr;
+	NETSOCKET socket;
+	NETSTATS stats;
+} NETCONNECTION;
+
+typedef struct
+{
+	NETCONNECTION conn;
+} NETSLOT;
+
+struct NETSERVER_t
+{
+	NETSOCKET socket;
+	NETSLOT slots[NETWORK_MAX_CLIENTS];
+	int max_clients;
+	NETFUNC_NEWCLIENT new_client;
+	NETFUNC_NEWCLIENT del_client;
+	void *user_ptr;
+	unsigned char recv_buffer[NETWORK_MAX_PACKET_SIZE];
+} ;
+
+struct NETCLIENT_t
+{
+	NETADDR4 server_addr;
+	NETSOCKET socket;
+	unsigned char recv_buffer[NETWORK_MAX_PACKET_SIZE];
+	
+	NETCONNECTION conn;
+};
+
+static void conn_reset_stats(NETCONNECTION *conn)
+{
+	mem_zero(&conn->stats, sizeof(conn->stats));
+}
+
+static void conn_reset(NETCONNECTION *conn)
+{
+	conn->seq = 0;
+	conn->ack = 0;
+	conn->remote_closed = 0;
+	
+	if(conn->state == NETWORK_CONNSTATE_ONLINE ||
+		conn->state == NETWORK_CONNSTATE_ERROR)
+	{
+		conn->disconnected++;
+	}
+		
+	conn->state = NETWORK_CONNSTATE_OFFLINE;
+	conn->last_send_time = 0;
+	conn->last_recv_time = 0;
+	conn->last_update_time = 0;
+	conn->token = -1;
+	
+	rb_clear(&conn->buffer);
+}
+
+
+static const char *conn_error(NETCONNECTION *conn)
+{
+	return conn->error_string;
+}
+
+static void conn_set_error(NETCONNECTION *conn, const char *str)
+{
+	strcpy(conn->error_string, str);
+}
+
+/*
+static int conn_state(NETCONNECTION *conn)
+{
+	return conn->state;
+}*/
+
+static void conn_init(NETCONNECTION *conn, NETSOCKET socket)
+{
+	conn_reset(conn);
+	conn_reset_stats(conn);
+	conn->socket = socket;
+	conn->connected = 0;
+	conn->disconnected = 0;
+	rb_init(&conn->buffer);
+	mem_zero(conn->error_string, sizeof(conn->error_string));
+}
+
+static void conn_ack(NETCONNECTION *conn, int ack)
+{
+	while(1)
+	{
+		RINGBUFFER_ITEM *item = conn->buffer.first;
+		NETPACKETDATA *resend;
+		if(!item)
+			break;
+			
+		resend = (NETPACKETDATA *)rb_item_data(item);
+		if(resend->seq <= ack || (ack < NETWORK_MAX_SEQACK/3 && resend->seq > NETWORK_MAX_SEQACK/2))
+			rb_pop_first(&conn->buffer);
+		else
+			break;
+	}
+}
+
+static void conn_send_raw(NETCONNECTION *conn, NETPACKETDATA *data)
+{
+	conn->last_send_time = time_get();
+	conn->stats.send_packets++;
+	conn->stats.send_bytes += data->data_size + NETWORK_HEADER_SIZE;
+	send_packet(conn->socket, &conn->peeraddr, data);
+}
+
+static void conn_resend(NETCONNECTION *conn)
+{
+	RINGBUFFER_ITEM *item = conn->buffer.first;
+	while(item)
+	{
+		NETPACKETDATA *resend = (NETPACKETDATA *)rb_item_data(item);
+		conn->stats.resend_packets++;
+		conn->stats.resend_bytes += resend->data_size + NETWORK_HEADER_SIZE;
+		conn_send_raw(conn, resend);
+		item = item->next;
+	}
+}
+
+static void conn_send(NETCONNECTION *conn, int flags, int data_size, const void *data)
+{
+	NETPACKETDATA p;
+
+	if(flags&NETWORK_PACKETFLAG_VITAL)
+		conn->seq = (conn->seq+1)%NETWORK_MAX_SEQACK;
+
+	p.ID[0] = 'T';
+	p.ID[1] = 'W';
+	p.version = NETWORK_VERSION;
+	p.flags = flags;
+	p.seq = conn->seq;
+	p.ack = conn->ack;
+	p.crc = 0;
+	p.token = conn->token;
+	p.data_size = data_size;
+	p.data = (unsigned char *)data;
+	p.first_send_time = time_get();
+
+	if(flags&NETWORK_PACKETFLAG_VITAL)
+	{
+		/* save packet if we need to resend */
+		NETPACKETDATA *resend = (NETPACKETDATA *)rb_alloc(&conn->buffer, sizeof(NETPACKETDATA)+data_size);
+		*resend = p;
+		resend->data = (unsigned char *)(resend+1);
+		mem_copy(resend->data, p.data, p.data_size);
+	}
+	
+	/* TODO: calc crc */
+	conn_send_raw(conn, &p);
+}
+
+static int conn_connect(NETCONNECTION *conn, NETADDR4 *addr)
+{
+	if(conn->state != NETWORK_CONNSTATE_OFFLINE)
+		return -1;
+	
+	/* init connection */
+	conn_reset(conn);
+	conn->peeraddr = *addr;
+	conn->token = current_token++;
+	mem_zero(conn->error_string, sizeof(conn->error_string));
+	conn->state = NETWORK_CONNSTATE_CONNECT;
+	conn_send(conn, NETWORK_PACKETFLAG_CONNECT, 0, 0);
+	return 0;
+}
+
+static void conn_disconnect(NETCONNECTION *conn, const char *reason)
+{
+	if(conn->remote_closed == 0)
+	{
+		if(reason)
+			conn_send(conn, NETWORK_PACKETFLAG_CLOSE, strlen(reason)+1, reason);
+		else
+			conn_send(conn, NETWORK_PACKETFLAG_CLOSE, 0, 0);
+
+		conn->error_string[0] = 0;
+		if(reason)
+			strcpy(conn->error_string, reason);
+	}
+	
+	conn_reset(conn);
+}
+
+static int conn_feed(NETCONNECTION *conn, NETPACKETDATA *p, NETADDR4 *addr)
+{
+	conn->last_recv_time = time_get();
+	conn->stats.recv_packets++;
+	conn->stats.recv_bytes += p->data_size + NETWORK_HEADER_SIZE;
+	
+	if(p->flags&NETWORK_PACKETFLAG_CLOSE)
+	{
+		conn->state = NETWORK_CONNSTATE_ERROR;
+		conn->remote_closed = 1;
+		
+		if(p->data_size)
+			conn_set_error(conn, (char *)p->data);
+		else
+			conn_set_error(conn, "no reason given");
+		if(config.debug)
+			dbg_msg("conn", "closed reason='%s'", conn_error(conn));
+		return 0;
+	}
+	
+	if(conn->state == NETWORK_CONNSTATE_OFFLINE)
+	{
+		if(p->flags == NETWORK_PACKETFLAG_CONNECT)
+		{
+			/* send response and init connection */
+			conn->state = NETWORK_CONNSTATE_ONLINE;
+			conn->connected++;
+			conn->peeraddr = *addr;
+			conn->token = p->token;
+			conn_send(conn, NETWORK_PACKETFLAG_CONNECT|NETWORK_PACKETFLAG_ACCEPT, 0, 0);
+			if(config.debug)
+				dbg_msg("connection", "got connection, sending connect+accept");
+		}
+	}
+	else if(net_addr4_cmp(&conn->peeraddr, addr) == 0)
+	{
+		if(p->token != conn->token)
+			return 0;
+
+		if(conn->state == NETWORK_CONNSTATE_ONLINE)
+		{
+			/* remove packages that are acked */
+			conn_ack(conn, p->ack);
+			
+			/* check if resend is requested */
+			if(p->flags&NETWORK_PACKETFLAG_RESEND)
+				conn_resend(conn);
+				
+			if(p->flags&NETWORK_PACKETFLAG_VITAL)
+			{
+				if(p->seq == (conn->ack+1)%NETWORK_MAX_SEQACK)
+				{
+					/* in sequence */
+					conn->ack = (conn->ack+1)%NETWORK_MAX_SEQACK;
+				}
+				else
+				{
+					/* out of sequence, request resend */
+					dbg_msg("conn", "asking for resend %d %d", p->seq, (conn->ack+1)%NETWORK_MAX_SEQACK);
+					conn_send(conn, NETWORK_PACKETFLAG_RESEND, 0, 0);
+					return 0;
+				}
+			}
+			else
+			{
+				if(p->seq > conn->ack)
+					conn_send(conn, NETWORK_PACKETFLAG_RESEND, 0, 0);
+			}
+			
+			if(p->data_size == 0)
+				return 0;
+				
+			return 1;
+		}
+		else if(conn->state == NETWORK_CONNSTATE_CONNECT)
+		{
+			/* connection made */
+			if(p->flags == (NETWORK_PACKETFLAG_CONNECT|NETWORK_PACKETFLAG_ACCEPT))
+			{
+				conn_send(conn, NETWORK_PACKETFLAG_ACCEPT, 0, 0);
+				conn->state = NETWORK_CONNSTATE_ONLINE;
+				conn->connected++;
+				dbg_msg("connection", "got connect+accept, sending accept. connection online");
+			}
+		}
+		/*
+		else if(conn->state == NETWORK_CONNSTATE_CONNECTACCEPTED)
+		{
+			// connection made
+			if(p->flags == NETWORK_PACKETFLAG_ACCEPT)
+			{
+				conn->state = NETWORK_CONNSTATE_ONLINE;
+				dbg_msg("connection", "got accept. connection online");
+			}
+		}*/
+		else
+		{
+			/* strange packet, wrong state */
+			conn->state = NETWORK_CONNSTATE_ERROR;
+			conn_set_error(conn, "strange state and packet");
+		}
+	}
+	else
+	{
+		/* strange packet, not ment for me */
+	}
+	
+	return 0;
+}
+
+
+
+static int conn_update(NETCONNECTION *conn)
+{
+	int64 now = time_get();
+
+	if(conn->state == NETWORK_CONNSTATE_OFFLINE || conn->state == NETWORK_CONNSTATE_ERROR)
+		return 0;
+
+	/* watch out for major hitches */
+	{
+		int64 delta = now-conn->last_update_time;
+		if(conn->last_update_time && delta > time_freq()/2)
+		{
+			RINGBUFFER_ITEM *item = conn->buffer.first;
+	
+			dbg_msg("conn", "hitch %d", (int)((delta*1000)/time_freq()));
+			conn->last_recv_time += delta;
+	
+			while(item)
+			{
+				NETPACKETDATA *resend = (NETPACKETDATA *)rb_item_data(item);
+				resend->first_send_time += delta;
+				item = item->next;
+			}
+		}
+
+		conn->last_update_time = now;
+	}
+		
+	
+	/* check for timeout */
+	if(conn->state != NETWORK_CONNSTATE_OFFLINE &&
+		conn->state != NETWORK_CONNSTATE_CONNECT &&
+		(now-conn->last_recv_time) > time_freq()*10)
+	{
+		conn->state = NETWORK_CONNSTATE_ERROR;
+		conn_set_error(conn, "timeout");
+	}
+	
+	/* check for large buffer errors */
+	if(conn->buffer.buffer_size > 1024*64)
+	{
+		conn->state = NETWORK_CONNSTATE_ERROR;
+		conn_set_error(conn, "too weak connection (out of buffer)");
+	}
+	
+	if(conn->buffer.first)
+	{
+		NETPACKETDATA *resend = (NETPACKETDATA *)(conn->buffer.first+1);
+		if(now-resend->first_send_time > time_freq()*10)
+		{
+			conn->state = NETWORK_CONNSTATE_ERROR;
+			conn_set_error(conn, "too weak connection (not acked for 10 seconds)");
+		}
+	}
+	
+	/* send keep alives if nothing has happend for 250ms */
+	if(conn->state == NETWORK_CONNSTATE_ONLINE)
+	{
+		if(time_get()-conn->last_send_time> time_freq()/4)
+			conn_send(conn, NETWORK_PACKETFLAG_VITAL, 0, 0);
+	}
+	else if(conn->state == NETWORK_CONNSTATE_CONNECT)
+	{
+		if(time_get()-conn->last_send_time > time_freq()/2) /* send a new connect every 500ms */
+			conn_send(conn, NETWORK_PACKETFLAG_CONNECT, 0, 0);
+	}
+	else if(conn->state == NETWORK_CONNSTATE_CONNECTACCEPTED)
+	{
+		if(time_get()-conn->last_send_time > time_freq()/2) /* send a new connect/accept every 500ms */
+			conn_send(conn, NETWORK_PACKETFLAG_CONNECT|NETWORK_PACKETFLAG_ACCEPT, 0, 0);
+	}
+	
+	return 0;
+}
+
+
+static int check_packet(unsigned char *buffer, int size, NETPACKETDATA *packet)
+{
+	/* check the size */
+	if(size < NETWORK_HEADER_SIZE || size > NETWORK_MAX_PACKET_SIZE)
+		return -1;
+	
+	/* read the packet */
+	packet->ID[0] = 'T';
+	packet->ID[1] = 'W';
+	packet->version = NETWORK_VERSION;
+	packet->flags = buffer[0];
+	packet->seq = ((buffer[1]&0xf0)<<4)|buffer[2];
+	packet->ack = ((buffer[1]&0x0f)<<8)|buffer[3];
+	packet->crc = 0;
+	packet->token = (buffer[4]<<8)|buffer[5];
+	packet->data_size = size - NETWORK_HEADER_SIZE;
+	packet->data = buffer+NETWORK_HEADER_SIZE;
+	
+	/* check the packet */
+	if(packet->ID[0] != 'T' || packet->ID[1] != 'W')
+		return 1;
+	
+	if(packet->version != NETWORK_VERSION)
+		return 1;
+
+	/* TODO: perform crc check */
+	
+	/* return success */
+	return 0;
+}
+
+NETSERVER *netserver_open(NETADDR4 bindaddr, int max_clients, int flags)
+{
+	int i;
+	NETSERVER *server;
+	NETSOCKET socket = net_udp4_create(bindaddr);
+	if(socket == NETSOCKET_INVALID)
+		return 0;
+	
+	server = (NETSERVER *)mem_alloc(sizeof(NETSERVER), 1);
+	mem_zero(server, sizeof(NETSERVER));
+	server->socket = socket;
+	server->max_clients = max_clients;
+	if(server->max_clients > NETWORK_MAX_CLIENTS)
+		server->max_clients = NETWORK_MAX_CLIENTS;
+	if(server->max_clients < 1)
+		server->max_clients = 1;
+	
+	for(i = 0; i < NETWORK_MAX_CLIENTS; i++)
+		conn_init(&server->slots[i].conn, server->socket);
+
+	return server;
+}
+
+int netserver_set_callbacks(NETSERVER *s, NETFUNC_NEWCLIENT new_client, NETFUNC_DELCLIENT del_client, void *user)
+{
+	s->new_client = new_client;
+	s->del_client = del_client;
+	s->user_ptr = user;
+	return 0;
+}
+
+int netserver_max_clients(NETSERVER *s)
+{
+	return s->max_clients;
+}
+
+int netserver_close(NETSERVER *s)
+{
+	/* TODO: implement me */
+	return 0;
+}
+
+int netserver_drop(NETSERVER *s, int client_id, const char *reason)
+{
+	/* TODO: insert lots of checks here */
+	dbg_msg("net_server", "client dropped. cid=%d reason=\"%s\"", client_id, reason);
+	conn_disconnect(&s->slots[client_id].conn, reason);
+
+	if(s->del_client)
+		s->del_client(client_id, s->user_ptr);
+		
+	return 0;
+}
+
+int netserver_update(NETSERVER *s)
+{
+	int i;
+	for(i = 0; i < s->max_clients; i++)
+	{
+		conn_update(&s->slots[i].conn);
+		if(s->slots[i].conn.state == NETWORK_CONNSTATE_ERROR)
+			netserver_drop(s, i, conn_error(&s->slots[i].conn));
+	}
+	return 0;
+}
+
+int netserver_recv(NETSERVER *s, NETPACKET *packet)
+{
+	NETPACKETDATA data;
+	int i, r, bytes, found;
+	NETADDR4 addr;
+	
+	while(1)
+	{
+		bytes = net_udp4_recv(s->socket, &addr, s->recv_buffer, NETWORK_MAX_PACKET_SIZE);
+
+		/* no more packets for now */
+		if(bytes <= 0)
+			break;
+		
+		r = check_packet(s->recv_buffer, bytes, &data);
+		if(r == 0)
+		{
+			if(data.flags&NETWORK_PACKETFLAG_CONNLESS)
+			{
+				/* connection less packets */
+				packet->client_id = -1;
+				packet->address = addr;
+				packet->flags = PACKETFLAG_CONNLESS;
+				packet->data_size = data.data_size;
+				packet->data = data.data;
+				return 1;		
+			}
+			else
+			{
+				/* ok packet, process it */
+				if(data.flags == NETWORK_PACKETFLAG_CONNECT)
+				{
+					found = 0;
+					
+					/* check if we already got this client */
+					for(i = 0; i < s->max_clients; i++)
+					{
+						if(s->slots[i].conn.state != NETWORK_CONNSTATE_OFFLINE &&
+							net_addr4_cmp(&s->slots[i].conn.peeraddr, &addr) == 0)
+						{
+							found = 1; /* silent ignore.. we got this client already */
+							break;
+						}
+					}
+					
+					/* client that wants to connect */
+					if(!found)
+					{
+						for(i = 0; i < s->max_clients; i++)
+						{
+							if(s->slots[i].conn.state == NETWORK_CONNSTATE_OFFLINE)
+							{
+								found = 1;
+								conn_feed(&s->slots[i].conn, &data, &addr);
+								if(s->new_client)
+									s->new_client(i, s->user_ptr);
+								break;
+							}
+						}
+					}
+					
+					if(!found)
+					{
+						/* send connectionless packet */
+						const char errstring[] = "server full";
+						NETPACKETDATA p;
+						p.ID[0] = 'T';
+						p.ID[1] = 'W';
+						p.version = NETWORK_VERSION;
+						p.flags = NETWORK_PACKETFLAG_CLOSE;
+						p.seq = 0;
+						p.ack = 0;
+						p.crc = 0;
+						p.token = data.token;
+						p.data_size = sizeof(errstring);
+						p.data = (unsigned char *)errstring;
+						send_packet(s->socket, &addr, &p);
+					}
+				}
+				else
+				{
+					/* find matching slot */
+					for(i = 0; i < s->max_clients; i++)
+					{
+						if(net_addr4_cmp(&s->slots[i].conn.peeraddr, &addr) == 0)
+						{
+							if(conn_feed(&s->slots[i].conn, &data, &addr))
+							{
+								if(data.data_size)
+								{
+									packet->client_id = i;	
+									packet->address = addr;
+									packet->flags = 0;
+									packet->data_size = data.data_size;
+									packet->data = data.data;
+									return 1;
+								}
+							}
+						}
+					}
+				}
+			}
+		}
+		else
+		{
+			/* errornous packet, drop it */
+			dbg_msg("server", "crazy packet");
+		}
+		
+		/* read header */
+		/* do checksum */
+	}	
+	
+	return 0;
+}
+
+int netserver_send(NETSERVER *s, NETPACKET *packet)
+{
+	dbg_assert(packet->data_size < NETWORK_MAX_PAYLOAD, "packet payload too big");
+	
+	if(packet->flags&PACKETFLAG_CONNLESS)
+	{
+		/* send connectionless packet */
+		NETPACKETDATA p;
+		p.ID[0] = 'T';
+		p.ID[1] = 'W';
+		p.version = NETWORK_VERSION;
+		p.flags = NETWORK_PACKETFLAG_CONNLESS;
+		p.seq = 0;
+		p.ack = 0;
+		p.crc = 0;
+		p.data_size = packet->data_size;
+		p.data = (unsigned char *)packet->data;
+		send_packet(s->socket, &packet->address, &p);
+	}
+	else
+	{
+		int flags  = 0;
+		dbg_assert(packet->client_id >= 0, "errornous client id");
+		dbg_assert(packet->client_id < s->max_clients, "errornous client id");
+		if(packet->flags&PACKETFLAG_VITAL)
+			flags |= NETWORK_PACKETFLAG_VITAL;
+		conn_send(&s->slots[packet->client_id].conn, flags, packet->data_size, packet->data);
+	}
+	return 0;
+}
+
+void netserver_stats(NETSERVER *s, NETSTATS *stats)
+{
+	int num_stats = sizeof(NETSTATS)/sizeof(int);
+	int *istats = (int *)stats;
+	int c, i;
+
+	mem_zero(stats, sizeof(NETSTATS));
+	
+	for(c = 0; c < s->max_clients; c++)
+	{
+		if(s->slots[c].conn.state != NETWORK_CONNSTATE_OFFLINE)
+		{
+			int *sstats = (int *)(&(s->slots[c].conn.stats));
+			for(i = 0; i < num_stats; i++)
+				istats[i] += sstats[i];
+		}
+	}
+}
+
+NETCLIENT *netclient_open(NETADDR4 bindaddr, int flags)
+{
+	NETCLIENT *client = (NETCLIENT *)mem_alloc(sizeof(NETCLIENT), 1);
+	mem_zero(client, sizeof(NETCLIENT));
+	client->socket = net_udp4_create(bindaddr);
+	conn_init(&client->conn, client->socket);
+	return client;
+}
+
+int netclient_close(NETCLIENT *c)
+{
+	/* TODO: implement me */
+	return 0;
+}
+
+int netclient_update(NETCLIENT *c)
+{
+	conn_update(&c->conn);
+	if(c->conn.state == NETWORK_CONNSTATE_ERROR)
+		netclient_disconnect(c, conn_error(&c->conn));
+	return 0;
+}
+
+int netclient_disconnect(NETCLIENT *c, const char *reason)
+{
+	dbg_msg("netclient", "disconnected. reason=\"%s\"", reason);
+	conn_disconnect(&c->conn, reason);
+	return 0;
+}
+
+int netclient_connect(NETCLIENT *c, NETADDR4 *addr)
+{
+	conn_connect(&c->conn, addr);
+	return 0;
+}
+
+int netclient_recv(NETCLIENT *c, NETPACKET *packet)
+{
+	while(1)
+	{
+		NETADDR4 addr;
+		NETPACKETDATA data;
+		int r;
+		int bytes = net_udp4_recv(c->socket, &addr, c->recv_buffer, NETWORK_MAX_PACKET_SIZE);
+
+		/* no more packets for now */
+		if(bytes <= 0)
+			break;
+		
+		r = check_packet(c->recv_buffer, bytes, &data);
+		
+		if(r == 0)
+		{
+			if(data.flags&NETWORK_PACKETFLAG_CONNLESS)
+			{
+				/* connection less packets */
+				packet->client_id = -1;
+				packet->address = addr;
+				packet->flags = PACKETFLAG_CONNLESS;
+				packet->data_size = data.data_size;
+				packet->data = data.data;
+				return 1;		
+			}
+			else
+			{
+				if(conn_feed(&c->conn, &data, &addr))
+				{
+					/* fill in packet */
+					packet->client_id = 0;
+					packet->address = addr;
+					packet->flags = 0;
+					packet->data_size = data.data_size;
+					packet->data = data.data;
+					return 1;
+				}
+				else
+				{
+					/* errornous packet, drop it */
+				}
+			}			
+		}
+	}
+	
+	return 0;
+}
+
+int netclient_send(NETCLIENT *c, NETPACKET *packet)
+{
+	dbg_assert(packet->data_size < NETWORK_MAX_PAYLOAD, "packet payload too big");
+	
+	if(packet->flags&PACKETFLAG_CONNLESS)
+	{
+		/* send connectionless packet */
+		NETPACKETDATA p;
+		p.ID[0] = 'T';
+		p.ID[1] = 'W';
+		p.version = NETWORK_VERSION;
+		p.flags = NETWORK_PACKETFLAG_CONNLESS;
+		p.seq = 0;
+		p.ack = 0;
+		p.crc = 0;
+		p.token = 0;
+		p.data_size = packet->data_size;
+		p.data = (unsigned char *)packet->data;
+		send_packet(c->socket, &packet->address, &p);
+	}
+	else
+	{
+		int flags = 0;		
+		dbg_assert(packet->client_id == 0, "errornous client id");
+		if(packet->flags&PACKETFLAG_VITAL)
+			flags |= NETWORK_PACKETFLAG_VITAL;
+		conn_send(&c->conn, flags, packet->data_size, packet->data);
+	}
+	return 0;
+}
+
+int netclient_state(NETCLIENT *c)
+{
+	if(c->conn.state == NETWORK_CONNSTATE_ONLINE)
+		return NETSTATE_ONLINE;
+	if(c->conn.state == NETWORK_CONNSTATE_OFFLINE)
+		return NETSTATE_OFFLINE;
+	return NETSTATE_CONNECTING;
+}
+
+int netclient_gotproblems(NETCLIENT *c)
+{
+	if(time_get() - c->conn.last_recv_time > time_freq())
+		return 1;
+	return 0;
+}
+
+void netclient_stats(NETCLIENT *c, NETSTATS *stats)
+{
+	*stats = c->conn.stats;
+}
+
+const char *netclient_error_string(NETCLIENT *c)
+{
+	return conn_error(&c->conn);
+}