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Annotation of sys/arch/m88k/m88k/in_cksum.c, Revision 1.1.1.1

1.1       nbrk        1: /*     $OpenBSD: in_cksum.c,v 1.2 2005/05/05 14:28:34 miod Exp $       */
                      2:
                      3: /*
                      4:  * Copyright (C) 1995, 1996 Wolfgang Solfrank.
                      5:  * Copyright (C) 1995, 1996 TooLs GmbH.
                      6:  * All rights reserved.
                      7:  *
                      8:  * Redistribution and use in source and binary forms, with or without
                      9:  * modification, are permitted provided that the following conditions
                     10:  * are met:
                     11:  * 1. Redistributions of source code must retain the above copyright
                     12:  *    notice, this list of conditions and the following disclaimer.
                     13:  * 2. Redistributions in binary form must reproduce the above copyright
                     14:  *    notice, this list of conditions and the following disclaimer in the
                     15:  *    documentation and/or other materials provided with the distribution.
                     16:  * 3. All advertising materials mentioning features or use of this software
                     17:  *    must display the following acknowledgement:
                     18:  *     This product includes software developed by TooLs GmbH.
                     19:  * 4. The name of TooLs GmbH may not be used to endorse or promote products
                     20:  *    derived from this software without specific prior written permission.
                     21:  *
                     22:  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
                     23:  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
                     24:  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
                     25:  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
                     26:  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
                     27:  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
                     28:  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
                     29:  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
                     30:  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
                     31:  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
                     32:  */
                     33:
                     34: #include <sys/param.h>
                     35: #include <sys/systm.h>
                     36: #include <sys/mbuf.h>
                     37: #include <sys/socketvar.h>
                     38: #include <netinet/in.h>
                     39: #include <netinet/in_systm.h>
                     40: #include <netinet/ip.h>
                     41: #include <netinet/ip_var.h>
                     42:
                     43: #define        REDUCE          (sum = (sum & 0xffff) + (sum >> 16))
                     44: #define        ROL             (sum <<= 8)
                     45: #define        ADDB            (ROL, sum += *w, byte_swapped ^= 1)
                     46: #define        ADDS            (sum += *(u_short *)w)
                     47: #define        SHIFT(n)        (w += (n), mlen -= (n))
                     48: #define        ADDCARRY        do { while (sum > 0xffff) REDUCE; } while (0)
                     49:
                     50: static __inline__ int
                     51: in_cksum_internal(struct mbuf *m, int off, int len, u_int sum)
                     52: {
                     53:        u_char *w;
                     54:        int mlen;
                     55:        int byte_swapped = 0;
                     56:
                     57:        for (; m && len; m = m->m_next) {
                     58:                if (m->m_len == 0)
                     59:                        continue;
                     60:                w = mtod(m, u_char *) + off;
                     61:                mlen = m->m_len - off;
                     62:                off = 0;
                     63:                if (len < mlen)
                     64:                        mlen = len;
                     65:                len -= mlen;
                     66:
                     67:                if ((long)w & 1) {
                     68:                        REDUCE;
                     69:                        ADDB;
                     70:                        SHIFT(1);
                     71:                }
                     72:                while (mlen >= 2) {
                     73:                        ADDS;
                     74:                        SHIFT(2);
                     75:                }
                     76:                REDUCE;
                     77:                if (mlen == 1)
                     78:                        ADDB;
                     79:        }
                     80:        if (byte_swapped) {
                     81:                REDUCE;
                     82:                ROL;
                     83:        }
                     84:        ADDCARRY;
                     85:        return (0xffff ^ sum);
                     86: }
                     87:
                     88: int
                     89: in_cksum(struct mbuf *m, int len)
                     90: {
                     91:        return (in_cksum_internal(m, 0, len, 0));
                     92: }
                     93:
                     94: int
                     95: in4_cksum(struct mbuf *m, uint8_t nxt, int off, int len)
                     96: {
                     97:        u_int16_t *w;
                     98:        u_int sum = 0;
                     99:        struct ipovly ipov;
                    100:
                    101:        if (nxt != 0) {
                    102:                /* pseudo header */
                    103:                bzero(&ipov, sizeof(ipov));
                    104:                ipov.ih_len = htons(len);
                    105:                ipov.ih_pr = nxt;
                    106:                ipov.ih_src = mtod(m, struct ip *)->ip_src;
                    107:                ipov.ih_dst = mtod(m, struct ip *)->ip_dst;
                    108:                w = (u_int16_t *)&ipov;
                    109:                /* assumes sizeof(ipov) == 20 */
                    110:                sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; sum += w[4];
                    111:                sum += w[5]; sum += w[6]; sum += w[7]; sum += w[8]; sum += w[9];
                    112:        }
                    113:
                    114:        /* skip unnecessary part */
                    115:        while (m && off > 0) {
                    116:                if (m->m_len > off)
                    117:                        break;
                    118:                off -= m->m_len;
                    119:                m = m->m_next;
                    120:        }
                    121:
                    122:        return (in_cksum_internal(m, off, len, sum));
                    123: }