ref: 080cc49f5000a4e82c015af79dd6e489a33d3f68
dir: /sys/src/cmd/unix/u9fs/remotehost.c/
#include <sys/types.h>
#include <sys/socket.h> /* various networking crud */
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netdb.h>
#include <plan9.h>
void
getremotehostname(char *name, int nname)
{
struct sockaddr_in sock;
struct hostent *hp;
uint len;
int on;
strecpy(name, name+nname, "unknown");
len = sizeof sock;
if(getpeername(0, (struct sockaddr*)&sock, (void*)&len) < 0)
return;
hp = gethostbyaddr((char *)&sock.sin_addr, sizeof (struct in_addr),
sock.sin_family);
if(hp == 0)
return;
strecpy(name, name+nname, hp->h_name);
on = 1;
setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, (char*)&on, sizeof(on));
on = 1;
setsockopt(0, IPPROTO_TCP, TCP_NODELAY, (char*)&on, sizeof(on));
}