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/* copyright (c) 2007 magnus auvinen, see licence.txt for more info */
#include <base/system.h>
#include <string.h> /* strlen */
#include "e_config.h"
#include "e_network.h"
#include "e_network_internal.h"
#include "e_huffman.h"
void recvinfo_clear(NETRECVINFO *info)
{
info->valid = 0;
}
void recvinfo_start(NETRECVINFO *info, NETADDR *addr, NETCONNECTION *conn, int cid)
{
info->addr = *addr;
info->conn = conn;
info->client_id = cid;
info->current_chunk = 0;
info->valid = 1;
}
/* TODO: rename this function */
int recvinfo_fetch_chunk(NETRECVINFO *info, NETCHUNK *chunk)
{
NETCHUNKHEADER header;
unsigned char *data = info->data.chunk_data;
int i;
while(1)
{
/* check for old data to unpack */
if(!info->valid || info->current_chunk >= info->data.num_chunks)
{
recvinfo_clear(info);
return 0;
}
/* TODO: add checking here so we don't read too far */
for(i = 0; i < info->current_chunk; i++)
{
data = unpack_chunk_header(data, &header);
data += header.size;
}
/* unpack the header */
data = unpack_chunk_header(data, &header);
info->current_chunk++;
/* handle sequence stuff */
if(info->conn && (header.flags&NET_CHUNKFLAG_VITAL))
{
if(header.sequence == (info->conn->ack+1)%NET_MAX_SEQUENCE)
{
/* in sequence */
info->conn->ack = (info->conn->ack+1)%NET_MAX_SEQUENCE;
}
else
{
/* out of sequence, request resend */
dbg_msg("conn", "asking for resend %d %d", header.sequence, (info->conn->ack+1)%NET_MAX_SEQUENCE);
conn_want_resend(info->conn);
continue; /* take the next chunk in the packet */
}
}
/* fill in the info */
chunk->client_id = info->client_id;
chunk->address = info->addr;
chunk->flags = 0;
chunk->data_size = header.size;
chunk->data = data;
return 1;
}
}
static IOHANDLE datalog = 0;
static HUFFMAN_STATE huffmanstate;
#define COMPRESSION 1
/* packs the data tight and sends it */
void send_packet_connless(NETSOCKET socket, NETADDR *addr, const void *data, int data_size)
{
unsigned char buffer[NET_MAX_PACKETSIZE];
buffer[0] = 0xff;
buffer[1] = 0xff;
buffer[2] = 0xff;
buffer[3] = 0xff;
buffer[4] = 0xff;
buffer[5] = 0xff;
mem_copy(&buffer[6], data, data_size);
net_udp_send(socket, addr, buffer, 6+data_size);
}
void send_packet(NETSOCKET socket, NETADDR *addr, NETPACKETCONSTRUCT *packet)
{
unsigned char buffer[NET_MAX_PACKETSIZE];
int compressed_size = -1;
int final_size = -1;
/* log the data */
if(datalog)
{
io_write(datalog, &packet->data_size, sizeof(packet->data_size));
io_write(datalog, &packet->chunk_data, packet->data_size);
}
/* compress if its enabled */
if(COMPRESSION)
compressed_size = huffman_compress(&huffmanstate, packet->chunk_data, packet->data_size, &buffer[3], NET_MAX_PACKETSIZE-4);
/* check if the compression was enabled, successful and good enough */
if(compressed_size > 0 && compressed_size < packet->data_size)
{
final_size = compressed_size;
packet->flags |= NET_PACKETFLAG_COMPRESSION;
}
else
{
/* use uncompressed data */
final_size = packet->data_size;
mem_copy(&buffer[3], packet->chunk_data, packet->data_size);
packet->flags &= ~NET_PACKETFLAG_COMPRESSION;
}
/* set header and send the packet if all things are good */
if(final_size >= 0)
{
buffer[0] = ((packet->flags<<4)&0xf0)|((packet->ack>>8)&0xf);
buffer[1] = packet->ack&0xff;
buffer[2] = packet->num_chunks;
net_udp_send(socket, addr, buffer, NET_PACKETHEADERSIZE+final_size);
}
}
/* TODO: rename this function */
int unpack_packet(unsigned char *buffer, int size, NETPACKETCONSTRUCT *packet)
{
/* check the size */
if(size < NET_PACKETHEADERSIZE || size > NET_MAX_PACKETSIZE)
{
dbg_msg("", "packet too small, %d", size);
return -1;
}
/* read the packet */
packet->flags = buffer[0]>>4;
packet->ack = ((buffer[0]&0xf)<<8) | buffer[1];
packet->num_chunks = buffer[2];
packet->data_size = size - NET_PACKETHEADERSIZE;
if(packet->flags&NET_PACKETFLAG_CONNLESS)
{
packet->flags = NET_PACKETFLAG_CONNLESS;
packet->ack = 0;
packet->num_chunks = 0;
packet->data_size = size - 6;
mem_copy(packet->chunk_data, &buffer[6], packet->data_size);
}
else
{
if(packet->flags&NET_PACKETFLAG_COMPRESSION)
huffman_decompress(&huffmanstate, &buffer[3], packet->data_size, packet->chunk_data, sizeof(packet->chunk_data));
else
mem_copy(packet->chunk_data, &buffer[3], packet->data_size);
}
/* return success */
return 0;
}
/* TODO: change the arguments of this function */
unsigned char *pack_chunk_header(unsigned char *data, int flags, int size, int sequence)
{
data[0] = ((flags&3)<<6)|((size>>4)&0x3f);
data[1] = (size&0xf);
if(flags&NET_CHUNKFLAG_VITAL)
{
data[1] |= (sequence>>2)&0xf0;
data[2] = sequence&0xff;
return data + 3;
}
return data + 2;
}
unsigned char *unpack_chunk_header(unsigned char *data, NETCHUNKHEADER *header)
{
header->flags = (data[0]>>6)&3;
header->size = ((data[0]&0x3f)<<4) | (data[1]&0xf);
header->sequence = -1;
if(header->flags&NET_CHUNKFLAG_VITAL)
{
header->sequence = ((data[1]&0xf0)<<2) | data[2];
return data + 3;
}
return data + 2;
}
void netcommon_openlog(const char *filename)
{
datalog = io_open(filename, IOFLAG_WRITE);
}
static const unsigned freq_table[256+1] = {
1<<30,4545,2657,431,1950,919,444,482,2244,617,838,542,715,1814,304,240,754,212,647,186,
283,131,146,166,543,164,167,136,179,859,363,113,157,154,204,108,137,180,202,176,
872,404,168,134,151,111,113,109,120,126,129,100,41,20,16,22,18,18,17,19,
16,37,13,21,362,166,99,78,95,88,81,70,83,284,91,187,77,68,52,68,
59,66,61,638,71,157,50,46,69,43,11,24,13,19,10,12,12,20,14,9,
20,20,10,10,15,15,12,12,7,19,15,14,13,18,35,19,17,14,8,5,
15,17,9,15,14,18,8,10,2173,134,157,68,188,60,170,60,194,62,175,71,
148,67,167,78,211,67,156,69,1674,90,174,53,147,89,181,51,174,63,163,80,
167,94,128,122,223,153,218,77,200,110,190,73,174,69,145,66,277,143,141,60,
136,53,180,57,142,57,158,61,166,112,152,92,26,22,21,28,20,26,30,21,
32,27,20,17,23,21,30,22,22,21,27,25,17,27,23,18,39,26,15,21,
12,18,18,27,20,18,15,19,11,17,33,12,18,15,19,18,16,26,17,18,
9,10,25,22,22,17,20,16,6,16,15,20,14,18,24,335,1517};
void netcommon_init()
{
huffman_init(&huffmanstate, freq_table);
}
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