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/* copyright (c) 2007 magnus auvinen, see licence.txt for more info */
#include <base/system.h>
#include <cstdlib>
struct PACKET
{
PACKET *prev;
PACKET *next;
NETADDR send_to;
int64 timestamp;
int id;
int data_size;
char data[1];
};
static PACKET *first = (PACKET *)0;
static PACKET *last = (PACKET *)0;
static int current_latency = 0;
struct PINGCONFIG
{
int base;
int flux;
int spike;
int loss;
};
static PINGCONFIG config_pings[] = {
// base flux spike loss
{0, 0, 0, 0},
{40, 20, 0, 0},
{140, 40, 0, 0},
};
static int config_numpingconfs = sizeof(config_pings)/sizeof(PINGCONFIG);
static int config_interval = 10; /* seconds between different pingconfigs */
static int config_log = 0;
static int config_reorder = 0;
int run(int port, NETADDR dest)
{
NETADDR src = {NETTYPE_IPV4, {0,0,0,0},port};
NETSOCKET socket = net_udp_create(src);
char buffer[1024*2];
int id = 0;
while(1)
{
static int lastcfg = 0;
int n = ((time_get()/time_freq())/config_interval) % config_numpingconfs;
PINGCONFIG ping = config_pings[n];
if(n != lastcfg)
dbg_msg("crapnet", "cfg = %d", n);
lastcfg = n;
// handle incomming packets
while(1)
{
// fetch data
int data_trash = 0;
NETADDR from;
int bytes = net_udp_recv(socket, &from, buffer, 1024*2);
if(bytes <= 0)
break;
if((rand()%100) < ping.loss) // drop the packet
{
if(config_log)
dbg_msg("crapnet", "dropped packet");
continue;
}
// create new packet
PACKET *p = (PACKET *)mem_alloc(sizeof(PACKET)+bytes, 1);
if(net_addr_comp(&from, &dest) == 0)
p->send_to = src; // from the server
else
{
src = from; // from the client
p->send_to = dest;
}
// queue packet
p->prev = last;
p->next = 0;
if(last)
last->next = p;
else
{
first = p;
last = p;
}
last = p;
// set data in packet
p->timestamp = time_get();
p->data_size = bytes;
p->id = id++;
mem_copy(p->data, buffer, bytes);
if(id > 20 && bytes > 6 && data_trash)
{
p->data[6+(rand()%(bytes-6))] = rand()&255; // modify a byte
if((rand()%10) == 0)
{
p->data_size -= rand()%32;
if(p->data_size < 6)
p->data_size = 6;
}
}
if(config_log)
dbg_msg("crapnet", "<< %08d %d.%d.%d.%d:%5d (%d)", p->id, from.ip[0], from.ip[1], from.ip[2], from.ip[3], from.port, p->data_size);
}
//
while(1)
{
if(first && (time_get()-first->timestamp) > current_latency)
{
PACKET *p = first;
char flags[] = " ";
if(config_reorder && (rand()%2) == 0 && first->next)
{
flags[0] = 'R';
p = first->next;
}
if(p->next)
p->next->prev = 0;
else
last = p->prev;
if(p->prev)
p->prev->next = p->next;
else
first = p->next;
PACKET *cur = first;
while(cur)
{
dbg_assert(cur != p, "p still in list");
cur = cur->next;
}
// send and remove packet
//if((rand()%20) != 0) // heavy packetloss
net_udp_send(socket, &p->send_to, p->data, p->data_size);
// update lag
double flux = rand()/(double)RAND_MAX;
int ms_spike = ping.spike;
int ms_flux = ping.flux;
int ms_ping = ping.base;
current_latency = ((time_freq()*ms_ping)/1000) + (int64)(((time_freq()*ms_flux)/1000)*flux); // 50ms
if(ms_spike && (p->id%100) == 0)
{
current_latency += (time_freq()*ms_spike)/1000;
flags[1] = 'S';
}
if(config_log)
{
dbg_msg("crapnet", ">> %08d %d.%d.%d.%d:%5d (%d) %s", p->id,
p->send_to.ip[0], p->send_to.ip[1],
p->send_to.ip[2], p->send_to.ip[3],
p->send_to.port, p->data_size, flags);
}
mem_free(p);
}
else
break;
}
thread_sleep(1);
}
}
int main(int argc, char **argv)
{
NETADDR a = {NETTYPE_IPV4, {127,0,0,1},8303};
dbg_logger_stdout();
run(8302, a);
return 0;
}
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