920b965865
in_cksum.h required ip.h to be included for struct ip. To be able to use some general checksum functions like in_addword() in a non-IPv4 context, limit the (also exported to user space) IPv4 specific functions to the times, when the ip.h header is present and IPVERSION is defined (to 4). We should consider more general checksum (updating) functions to also allow easier incremental checksum updates in the L3/4 stack and firewalls, as well as ponder further requirements by certain NIC drivers needing slightly different pseudo values in offloading cases. Thinking in terms of a better "library". Sponsored by: The FreeBSD Foundation Sponsored by: iXsystems Reviewed by: gnn (as part of the whole) MFC After: 3 days
149 lines
4.0 KiB
C
149 lines
4.0 KiB
C
/*-
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from tahoe: in_cksum.c 1.2 86/01/05
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* from: @(#)in_cksum.c 1.3 (Berkeley) 1/19/91
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* from: Id: in_cksum.c,v 1.8 1995/12/03 18:35:19 bde Exp
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* $FreeBSD$
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*/
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#ifndef _MACHINE_IN_CKSUM_H_
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#define _MACHINE_IN_CKSUM_H_ 1
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#ifndef _SYS_CDEFS_H_
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#error this file needs sys/cdefs.h as a prerequisite
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#endif
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/*
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* MP safe (alfred)
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*/
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#include <sys/cdefs.h>
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#define in_cksum(m, len) in_cksum_skip(m, len, 0)
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/*
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* It it useful to have an Internet checksum routine which is inlineable
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* and optimized specifically for the task of computing IP header checksums
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* in the normal case (where there are no options and the header length is
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* therefore always exactly five 32-bit words.
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*/
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#if defined(__GNUCLIKE_ASM) && !defined(__INTEL_COMPILER)
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#if defined(IPVERSION) && (IPVERSION == 4)
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static __inline u_int
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in_cksum_hdr(const struct ip *ip)
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{
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u_int sum = 0;
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__asm(
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"addl %1, %0\n"
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"adcl %2, %0\n"
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"adcl %3, %0\n"
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"adcl %4, %0\n"
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"adcl %5, %0\n"
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"adcl $0, %0"
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: "+r" (sum)
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: "g" (((const u_int32_t *)ip)[0]),
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"g" (((const u_int32_t *)ip)[1]),
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"g" (((const u_int32_t *)ip)[2]),
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"g" (((const u_int32_t *)ip)[3]),
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"g" (((const u_int32_t *)ip)[4])
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: "cc"
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);
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sum = (sum & 0xffff) + (sum >> 16);
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if (sum > 0xffff)
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sum -= 0xffff;
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return ~sum & 0xffff;
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}
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static __inline void
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in_cksum_update(struct ip *ip)
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{
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int __tmpsum;
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__tmpsum = (int)ntohs(ip->ip_sum) + 256;
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ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16));
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}
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#endif
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static __inline u_short
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in_addword(u_short sum, u_short b)
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{
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__asm(
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"addw %1, %0\n"
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"adcw $0, %0"
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: "+r" (sum)
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: "g" (b)
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: "cc"
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);
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return (sum);
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}
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static __inline u_short
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in_pseudo(u_int sum, u_int b, u_int c)
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{
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__asm(
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"addl %1, %0\n"
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"adcl %2, %0\n"
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"adcl $0, %0"
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: "+r" (sum)
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: "g" (b),
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"g" (c)
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: "cc"
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);
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sum = (sum & 0xffff) + (sum >> 16);
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if (sum > 0xffff)
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sum -= 0xffff;
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return (sum);
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}
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#else
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#if defined(IPVERSION) && (IPVERSION == 4)
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#define in_cksum_update(ip) \
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do { \
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int __tmpsum; \
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__tmpsum = (int)ntohs(ip->ip_sum) + 256; \
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ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16)); \
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} while(0)
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#endif
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#endif
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#ifdef _KERNEL
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#if !defined(__GNUCLIKE_ASM) || defined(__INTEL_COMPILER)
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#if defined(IPVERSION) && (IPVERSION == 4)
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u_int in_cksum_hdr(const struct ip *ip);
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#endif
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u_short in_addword(u_short sum, u_short b);
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u_short in_pseudo(u_int sum, u_int b, u_int c);
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#endif
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u_short in_cksum_skip(struct mbuf *m, int len, int skip);
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#endif /* _KERNEL */
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#endif /* _MACHINE_IN_CKSUM_H_ */
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