/* $OpenBSD: sum1.c,v 1.4 2003/06/03 02:56:06 millert Exp $ */ /* $NetBSD: sum1.c,v 1.5 1996/02/27 21:17:27 cgd Exp $ */ /*- * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef lint #if 0 static char sccsid[] = "@(#)sum1.c 8.1 (Berkeley) 6/6/93"; static char rcsid[] = "$NetBSD: sum1.c,v 1.5 1996/02/27 21:17:27 cgd Exp $"; #else static char rcsid[] = "$OpenBSD: sum1.c,v 1.4 2003/06/03 02:56:06 millert Exp $"; #endif #endif /* not lint */ #include #include #include "extern.h" int csum1(fd, cval, clen) int fd; u_int32_t *cval, *clen; { u_int32_t total; int nr; u_int crc; u_char *p; u_char buf[8192]; /* * 16-bit checksum, rotating right before each addition; * overflow is discarded. */ crc = total = 0; while ((nr = read(fd, buf, sizeof(buf))) > 0) for (total += nr, p = buf; nr--; ++p) { if (crc & 1) crc |= 0x10000; crc = ((crc >> 1) + *p) & 0xffff; } if (nr < 0) return(1); *cval = crc; *clen = total; return(0); }