diff options
Diffstat (limited to 'cpukit/libnetworking/netinet/in_cksum.c')
| -rw-r--r-- | cpukit/libnetworking/netinet/in_cksum.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/cpukit/libnetworking/netinet/in_cksum.c b/cpukit/libnetworking/netinet/in_cksum.c new file mode 100644 index 0000000000..39e85e14ae --- /dev/null +++ b/cpukit/libnetworking/netinet/in_cksum.c @@ -0,0 +1,177 @@ +/* + * Copyright (c) 1988, 1992, 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. + * 4. 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. + * + * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 + * $Id$ + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include <sys/param.h> +#include <sys/mbuf.h> + +/* + * Try to use a CPU specific version, then punt to the portable C one. + */ + + +#if (defined(__GNUC__) && (defined(__arm__) && !defined(__thumb__))) + +/* This currently does not support Thumb assembly */ +#include "in_cksum_arm.h" + +#elif (defined(__GNUC__) && defined(__i386__)) + +#include "in_cksum_i386.h" + +#elif (defined(__GNUC__) && (defined(__mc68000__) || defined(__m68k__))) + +#include "in_cksum_m68k.h" +#elif (defined(__GNUC__) && defined(__PPC__)) + +#include "in_cksum_powerpc.h" + +#else + +#include <stdio.h> /* for puts */ + +/* + * Checksum routine for Internet Protocol family headers (Portable Version). + * + * This routine is very heavily used in the network + * code and should be modified for each CPU to be as fast as possible. + */ + +#define ADDCARRY(x) (x > 65535L ? x -= 65535L : x) +#define REDUCE \ + {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);} + +int +in_cksum( + struct mbuf *m, + uint32_t len ) +{ + register u_short *w; + register int32_t sum = 0; + register int32_t mlen = 0; + int byte_swapped = 0; + + union { + char c[2]; + u_short s; + } s_util; + union { + u_short s[2]; + long l; + } l_util; + + for (;m && len; m = m->m_next) { + if (m->m_len == 0) + continue; + w = mtod(m, u_short *); + if (mlen == -1) { + /* + * The first byte of this mbuf is the continuation + * of a word spanning between this mbuf and the + * last mbuf. + * + * s_util.c[0] is already saved when scanning previous + * mbuf. + */ + s_util.c[1] = *(char *)w; + sum += s_util.s; + w = (u_short *)((char *)w + 1); + mlen = m->m_len - 1; + len--; + } else + mlen = m->m_len; + if (len < mlen) + mlen = len; + len -= mlen; + /* + * Force to even boundary. + */ + if ((1 & (intptr_t) w) && (mlen > 0)) { + REDUCE; + sum <<= 8; + s_util.c[0] = *(u_char *)w; + w = (u_short *)((char *)w + 1); + mlen--; + byte_swapped = 1; + } + /* + * Unroll the loop to make overhead from + * branches &c small. + */ + while ((mlen -= 32) >= 0) { + sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; + sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; + sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; + sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; + w += 16; + } + mlen += 32; + while ((mlen -= 8) >= 0) { + sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; + w += 4; + } + mlen += 8; + if (mlen == 0 && byte_swapped == 0) + continue; + REDUCE; + while ((mlen -= 2) >= 0) { + sum += *w++; + } + if (byte_swapped) { + REDUCE; + sum <<= 8; + byte_swapped = 0; + if (mlen == -1) { + s_util.c[1] = *(char *)w; + sum += s_util.s; + mlen = 0; + } else + mlen = -1; + } else if (mlen == -1) + s_util.c[0] = *(char *)w; + } + if (len) + puts("cksum: out of data"); + if (mlen == -1) { + /* The last mbuf has odd # of bytes. Follow the + standard (the odd byte may be shifted left by 8 bits + or not as determined by endian-ness of the machine) */ + s_util.c[1] = 0; + sum += s_util.s; + } + REDUCE; + return (~sum & 0xffff); +} +#endif |