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Annotation of sys/arch/m88k/m88k/in_cksum.c, Revision 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: }