/* * 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. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 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 * $Id$ */ #include #include #if defined(__mcoldfire__) # define IS_COLDFIRE 1 #else # define IS_COLDFIRE 0 #endif #define REDUCE { sum = (sum & 0xFFFF) + (sum >> 16); if (sum > 0xFFFF) sum -= 0xFFFF; } /* * Motorola 68k version of Internet Protocol Checksum routine * W. Eric Norum * Saskatchewan Accelerator Laboratory * August, 1998 */ int in_cksum( struct mbuf *m, int len ) { unsigned short *w; unsigned long sum = 0; int mlen = 0; int byte_swapped = 0; union { char c[2]; u_short s; } s_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 longword boundary. */ if (3 & (int)w) { REDUCE; if ((1 & (int) w) && (mlen > 0)) { sum <<= 8; s_util.c[0] = *(u_char *)w; w = (u_short *)((char *)w + 1); mlen--; byte_swapped = 1; } if ((2 & (int) w) && (mlen >= 2)) { sum += *w++; mlen -= 2; } } /* * Sum all the longwords in the buffer. * See RFC 1071 -- Computing the Internet Checksum. * It should work for all 68k family members. */ { unsigned long tcnt = mlen, t1; __asm__ volatile ( "movel %2,%3\n\t" "lsrl #6,%2 | count/64 = # loop traversals\n\t" "andl #0x3c,%3 | Then find fractions of a chunk\n\t" "negl %3\n\t | Each long uses 4 instruction bytes\n\t" #if IS_COLDFIRE "addql #1,%2 | Clear X (extended carry flag)\n\t" "subql #1,%2 | \n\t" #else "andi #0xf,%%cc | Clear X (extended carry flag)\n\t" #endif "jmp %%pc@(2f-.-2:b,%3) | Jump into loop\n" "1: | Begin inner loop...\n\t" "movel %1@+,%3 | 0: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n\t" "movel %1@+,%3 | 1: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n\t" "movel %1@+,%3 | 2: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n\t" "movel %1@+,%3 | 3: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n\t" "movel %1@+,%3 | 4: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n\t" "movel %1@+,%3 | 5: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n\t" "movel %1@+,%3 | 6: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n\t" "movel %1@+,%3 | 7: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n\t" "movel %1@+,%3 | 8: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n\t" "movel %1@+,%3 | 9: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n\t" "movel %1@+,%3 | A: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n\t" "movel %1@+,%3 | B: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n\t" "movel %1@+,%3 | C: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n\t" "movel %1@+,%3 | D: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n\t" "movel %1@+,%3 | E: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n\t" "movel %1@+,%3 | F: Fetch 32-bit word\n\t" "addxl %3,%0 | Add word + previous carry\n" "2: | End of unrolled loop\n\t" #if IS_COLDFIRE "moveq #0,%3 | Add in last carry\n\t" "addxl %3,%0 |\n\t" "subql #1,%2 | Update loop count\n\t" "bplb 1b | Loop (with X clear) if not done\n\t" "movel #0xffff,%2 | Get word mask\n\t" "movel %0,%3 | Fold 32 bit sum to 16 bits\n\t" "swap %3 |\n\t" "andl %2,%0 | Mask to 16-bit sum\n\t" "andl %2,%3 | Mask to 16-bit sum\n\t" "addl %3,%0 |\n\t" "movel %0,%3 | Add in last carry\n\t" "swap %3 |\n\t" "addl %3,%0 |\n\t" "andl %2,%0 | Mask to 16-bit sum\n\t" #else "dbf %2,1b | (NB- dbf doesn't affect X)\n\t" "movel %0,%3 | Fold 32 bit sum to 16 bits\n\t" "swap %3 | (NB- swap doesn't affect X)\n\t" "addxw %3,%0 |\n\t" "moveq #0,%3 | Add in last carry\n\t" "addxw %3,%0 |\n\t" "andl #0xffff,%0 | Mask to 16-bit sum\n" #endif : "=d" (sum), "=a" (w), "=d" (tcnt) , "=d" (t1) : "0" (sum), "1" (w), "2" (tcnt) : "cc", "memory"); } mlen &= 3; /* * Soak up the last 1, 2 or 3 bytes */ 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) sum = 0xDEAD; 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); }