sys/sys/in_cksum.h

   1 /*
   2  * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  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
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      (note: completely rewritten for DragonFly)
  35  *
  36  *      from tahoe:     in_cksum.c      1.2     86/01/05
  37  *      from:           @(#)in_cksum.c  1.3 (Berkeley) 1/19/91
  38  *      from: Id: in_cksum.c,v 1.8 1995/12/03 18:35:19 bde Exp
  39  * $FreeBSD: src/sys/i386/include/in_cksum.h,v 1.7.2.2 2002/07/02 04:03:04 jdp Exp $
  40  * $DragonFly: src/sys/sys/in_cksum.h,v 1.4 2006/05/20 02:42:13 dillon Exp $
  41  */
  42
  43 #ifndef _SYS_IN_CKSUM_H_
  44 #define _SYS_IN_CKSUM_H_
  45
  46 #ifndef _SYS_TYPES_H_
  47 #include <sys/types.h>
  48 #endif
  49 #ifndef _MACHINE_STDINT_H_
  50 #include <machine/stdint.h>
  51 #endif
  52
  53 #ifdef _KERNEL
  54
  55 struct ip;
  56 struct mbuf;
  57
  58 __uint32_t in_cksum_range(struct mbuf *m, int nxt, int offset, int bytes);
  59 __uint32_t asm_ones32(const void *buf, int count);      /* in 32 bit words */
  60
  61 static __inline u_int
  62 in_cksum(struct mbuf *m, int len)
  63 {
  64     return(in_cksum_range(m, 0, 0, len));
  65 }
  66
  67 static __inline u_int
  68 in_cksum_skip(struct mbuf *m, int len, int skip)
  69 {
  70     return(in_cksum_range(m, 0, skip, len - skip));
  71 }
  72
  73 static __inline u_int
  74 in_cksum_hdr(const struct ip *ip)
  75 {
  76     __uint32_t sum;
  77
  78     sum = asm_ones32((const void *)ip, 5);      /* 5x4 = 20 bytes */
  79     sum = (sum >> 16) + (sum & 0xFFFF);
  80     if (sum > 0xFFFF)
  81         ++sum;
  82     return(~sum & 0xFFFF);
  83 }
  84
  85 #endif
  86
  87 static __inline u_short
  88 in_addword(u_short sum, u_short b)
  89 {
  90     /* __volatile is necessary because the condition codes are used. */
  91     __asm __volatile ("addw %1, %0; adcw $0,%0" : "+r" (sum) : "r" (b));
  92
  93     return (sum);
  94 }
  95
  96 static __inline u_short
  97 in_pseudo(u_int sum, u_int b, u_int c)
  98 {
  99     /* __volatile is necessary because the condition codes are used. */
 100     __asm __volatile ("addl %1,%0; adcl %2,%0; adcl $0,%0"
 101                         : "+r" (sum)
 102                         : "g" (b), "g" (c));
 103     sum = (sum & 0xffff) + (sum >> 16);
 104     if (sum > 0xffff)
 105         sum -= 0xffff;
 106     return (sum);
 107 }
 108
 109 #endif /* _MACHINE_IN_CKSUM_H_ */