1 files changed, 43 insertions, 0 deletions
diff --git a/libntp/numtohost.c b/libntp/numtohost.c
new file mode 100644
index 0000000..6b250d6
--- /dev/null
+++ b/libntp/numtohost.c
@@ -0,0 +1,43 @@
+/*
+ * numtohost - convert network number to host name.
+ */
+#include <config.h>
+
+#include <sys/types.h>
+#ifdef HAVE_NETINET_IN_H
+#include <netinet/in.h>		/* ntohl */
+#endif
+
+#include "ntp_fp.h"
+#include "ntp_stdlib.h"
+#include "lib_strbuf.h"
+
+#define	LOOPBACKNET	0x7f000000
+#define	LOOPBACKHOST	0x7f000001
+#define	LOOPBACKNETMASK	0xff000000
+
+char *
+numtohost(
+	u_int32 netnum
+	)
+{
+	char *bp;
+	struct hostent *hp;
+
+	/*
+	 * This is really gross, but saves lots of hanging looking for
+	 * hostnames for the radio clocks.  Don't bother looking up
+	 * addresses on the loopback network except for the loopback
+	 * host itself.
+	 */
+	if ((((ntohl(netnum) & LOOPBACKNETMASK) == LOOPBACKNET)
+	     && (ntohl(netnum) != LOOPBACKHOST))
+	    || ((hp = gethostbyaddr((char *)&netnum, sizeof netnum, AF_INET))
+		== 0))
+	    return numtoa(netnum);
+	
+	LIB_GETBUF(bp);
+	strlcpy(bp, hp->h_name, LIB_BUFLENGTH);
+
+	return bp;
+}