int main(int argc, char** argv) {
char devname[IFNAMSIZ];
int ifd, pingd;
fd_set fds;
int maxfd;
struct timeval tv;
struct in_addr me;
int mask, server;
char packet[PACKLEN];
int len,tmp;
struct sockaddr_in sa;
struct in_addr buf;
socklen_t buflen;
struct icmphdr* icmph;
int iphl;
int faddr, taddr;
int id, seq=0;
if(argc<3) {
dbg("ICMP-Proxy, by koala_man\n");
dbg("Usage: %s magic ip\n",argv[0]);
dbg("Magic is any 2-char string, same for server and client\n");
dbg("For clients: ip is the public address for the server\n");
dbg("For servers: ip is the private /24-mask for clients\n");
exit(1);
}
if(inet_aton(argv[2],&me)<0) {
perror("inet_aton");
exit(1);
}
if(argv[1][0]!=0) id=argv[1][1]<<8;
id=id | argv[1][0];
dbg("Using id %x\n",id);
server=(((me.s_addr)>>24)&0xFF)==0;
mask=htonl(me.s_addr);
dbg("You're a %s\n",server?"server":"client");
dbg("Mask is %d: %s\n",mask,ntoa(mask));
strncpy(devname,"it%d",IFNAMSIZ);
ifd=opentun(devname);
dbg("Opened tun as %s\n",devname);
if((pingd=socket(AF_INET,SOCK_RAW,IPPROTO_ICMP))<0) {
perror("socket");
close(ifd);
exit(3);
}
targets=(int*)calloc(256,sizeof(struct in_addr));
maxfd=MAX(ifd,pingd)+1;
FD_ZERO(&fds);
while(1) {
FD_SET(pingd,&fds);
FD_SET(ifd,&fds);
tv.tv_sec=8; //XXX
tv.tv_usec=0;
dbg("\n");
tmp=select(maxfd,&fds,NULL,NULL,&tv);
if(tmp==0) {
if(server) continue;
icmph=(struct icmphdr*) packet;
icmph->type=ICMP_ECHO;
icmph->code=0;
icmph->checksum=0;
icmph->un.echo.sequence=seq++;
icmph->un.echo.id=id;
tmp=(sizeof(struct icmphdr));
icmph->checksum=in_sum(packet,tmp,0);
buflen=sizeof(struct sockaddr);
sa.sin_addr=me;
sendto(pingd,packet,tmp,0,(struct sockaddr*)&sa,buflen);
dbg("Ping!\n");
} else {
if(FD_ISSET(pingd,&fds)) {
dbg("Got a ping\n");
buflen=sizeof(struct sockaddr);
len=recvfrom(pingd,packet,PACKLEN,0,(struct sockaddr*)&sa,&buflen);
dbg("Recvfrom=%d\n",len);
iphl=packet[0]&0x0F;
dbg("Packet header: %d\n",iphl);
if(iphl<5) {
dbg("Bad packet, too short header.\n");
continue;
}
taddr=ntohl(((int*)packet)[3]); //tunnel from
faddr=ntohl(((int*)packet)[iphl+8/4+3]); //packet from
if(!(taddr==mask || (server && (faddr & ~0xff)==mask))) {
dbg("IP from wrong place\n");
dbg(" Is %s\n",ntoa(faddr));
dbg(" or %s\n",ntoa(taddr));
dbg(" Should be %s\n",ntoa(mask));
continue;
}
icmph=(struct icmphdr*)(packet+iphl*4);
if(icmph->type != ICMP_ECHOREPLY) {
dbg("Not ICMP_ECHOREPLY\n");
continue;
}
if(icmph->un.echo.id!=id) {
dbg("Wrong ID\n");
continue;
}
if((len-iphl*4)<20 || len>PACKLEN) {
dbg("Not sane size\n");
continue;
}
if(server) {
dbg("Setting %x to %x\n",faddr,taddr);
settarget(faddr & 0xff,htonl(taddr));
}
write(ifd,packet+iphl*4+8,len-iphl*4-8);
}
if(FD_ISSET(ifd,&fds)) {
dbg("Got from if\n");
icmph=(struct icmphdr*) packet;
icmph->type=ICMP_ECHOREPLY;
icmph->code=0;
icmph->checksum=0;
icmph->un.echo.sequence=htons(seq++);
icmph->un.echo.id=id;
len=read(ifd,packet+8,TUNLEN);
dbg("read=%d\n",len);
if(len<0) {
perror("Read from if");
exit(4);
}
if(len==0) {
dbg("no data, lol?\n");
continue;
}
icmph->checksum=in_sum(packet,8+len,0);
buflen=sizeof(struct sockaddr);
if(server) {
tmp=ntohl(((int*)packet)[8/4+4]);
buf.s_addr=findtarget(tmp&0xff);
if(buf.s_addr==0) {
dbg("Don't know where to send, dropping\n");
continue;
}
sa.sin_addr=buf;
} else {
sa.sin_addr=me;
}
sendto(pingd,packet,len+8,0,(struct sockaddr*)&sa,buflen);
}
}
}
buflen=sizeof(struct sockaddr);
len=recvfrom(pingd,packet,PACKLEN,0,(struct sockaddr*)&sa,&buflen);
dbg("Recvfrom=%d\n",len);
write(2,packet,len);
close(ifd);
close(pingd);
return 0;
}
const Real GreensFunction2DAbs::p_int_theta_second(const Real r,
const Real theta,
const Real t) const
{
const Real r_0(this->getr0());
const Real a(this->geta());
const Real minusDt(-1e0 * this->getD() * t);
const Integer num_in_term_use(100);
const Integer num_out_term_use(100);
const Real threshold(CUTOFF);
Real sum(0e0);
Real term(0e0);
Integer n(1);
for(; n < num_out_term_use; ++n)
{
Real in_sum(0e0);
Real in_term(0e0);
Real in_term1(0e0);
Real in_term2(0e0);
Real in_term3(0e0);
Real a_alpha_mn(0e0);
Real alpha_mn(0e0);
Real Jn_r_alpha_mn(0e0);
Real Jn_r0_alpha_mn(0e0);
Real Jn_d_1_a_alpha_mn(0e0);// J_n-1(a alpha_mn)
Real Jn_p_1_a_alpha_mn(0e0);// J_n+1(a alpha_mn)
Real n_real(static_cast<double>(n));
int n_int(static_cast<int>(n));
Integer m(1);
for(; m < num_in_term_use; ++m)
{
a_alpha_mn = gsl_sf_bessel_zero_Jnu(n_real, m);
alpha_mn = a_alpha_mn / a;
Jn_r_alpha_mn = gsl_sf_bessel_Jn(n_int, r * alpha_mn);
Jn_r0_alpha_mn = gsl_sf_bessel_Jn(n_int, r_0 * alpha_mn);
Jn_d_1_a_alpha_mn = gsl_sf_bessel_Jn(n_int - 1, a_alpha_mn);
Jn_p_1_a_alpha_mn = gsl_sf_bessel_Jn(n_int + 1, a_alpha_mn);
in_term1 = std::exp(alpha_mn * alpha_mn * minusDt);
in_term2 = Jn_r_alpha_mn * Jn_r0_alpha_mn;
in_term3 = Jn_d_1_a_alpha_mn - Jn_p_1_a_alpha_mn;
in_term = in_term1 * in_term2 / (in_term3 * in_term3);
in_sum += in_term;
// std::cout << "inner sum " << in_sum << ", term" << in_term << std::endl;
if(fabs(in_term/in_sum) < threshold)
{
// std::cout << "normal exit. m = " << m << " second term" << std::endl;
break;
}
}
if(m == num_in_term_use)
std::cout << "warning: use term over num_in_term_use" << std::endl;
// term = in_sum * std::cos(n_real * theta);
term = in_sum * std::sin(n_real * theta) / n_real;
sum += term;
// std::cout << "outer sum " << sum << ", term" << term << std::endl;
if(fabs(in_sum / (n_real * sum)) < threshold)
{
/* if n * theta is a multiple of \pi, the term may be zero and *
* term/sum become also zero. this is a problem. sin is in a *
* regeon [-1, 1], so the order of term does not depend on *
* value of sin, so this considers only (in_sum / n_real). */
// std::cout << "normal exit. n = " << n << " second term" << std::endl;
break;
}
}
if(n == num_out_term_use)
std::cout << "warning: use term over num_out_term_use" << std::endl;
return (8e0 * sum / (M_PI * a * a));
}
