1 | #include <freebsd/machine/rtems-bsd-config.h> |
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2 | |
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3 | /* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */ |
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4 | |
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5 | /*- |
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6 | * Copyright (c) 1988, 1992, 1993 |
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7 | * The Regents of the University of California. All rights reserved. |
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8 | * Copyright (c) 1996 |
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9 | * Matt Thomas <matt@3am-software.com> |
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10 | * |
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11 | * Redistribution and use in source and binary forms, with or without |
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12 | * modification, are permitted provided that the following conditions |
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13 | * are met: |
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14 | * 1. Redistributions of source code must retain the above copyright |
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15 | * notice, this list of conditions and the following disclaimer. |
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16 | * 2. Redistributions in binary form must reproduce the above copyright |
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17 | * notice, this list of conditions and the following disclaimer in the |
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18 | * documentation and/or other materials provided with the distribution. |
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19 | * 3. All advertising materials mentioning features or use of this software |
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20 | * must display the following acknowledgement: |
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21 | * This product includes software developed by the University of |
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22 | * California, Berkeley and its contributors. |
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23 | * 4. Neither the name of the University nor the names of its contributors |
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24 | * may be used to endorse or promote products derived from this software |
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25 | * without specific prior written permission. |
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26 | * |
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27 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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28 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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29 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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30 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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31 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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32 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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33 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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34 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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35 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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36 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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37 | * SUCH DAMAGE. |
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38 | * |
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39 | * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 |
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40 | */ |
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41 | |
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42 | #include <freebsd/sys/cdefs.h> /* RCS ID & Copyright macro defns */ |
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43 | __FBSDID("$FreeBSD$"); |
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44 | |
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45 | #include <freebsd/sys/param.h> |
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46 | #include <freebsd/sys/mbuf.h> |
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47 | #include <freebsd/sys/systm.h> |
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48 | #include <freebsd/netinet/in_systm.h> |
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49 | #include <freebsd/netinet/in.h> |
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50 | #include <freebsd/netinet/ip.h> |
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51 | #include <freebsd/machine/in_cksum.h> |
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52 | |
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53 | /* |
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54 | * Checksum routine for Internet Protocol family headers |
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55 | * (Portable Alpha version). |
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56 | * |
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57 | * This routine is very heavily used in the network |
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58 | * code and should be modified for each CPU to be as fast as possible. |
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59 | */ |
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60 | |
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61 | #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) |
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62 | #define REDUCE32 \ |
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63 | { \ |
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64 | q_util.q = sum; \ |
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65 | sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ |
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66 | } |
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67 | #define REDUCE16 \ |
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68 | { \ |
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69 | q_util.q = sum; \ |
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70 | l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ |
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71 | sum = l_util.s[0] + l_util.s[1]; \ |
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72 | ADDCARRY(sum); \ |
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73 | } |
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74 | |
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75 | union l_util { |
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76 | u_int16_t s[2]; |
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77 | u_int32_t l; |
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78 | }; |
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79 | union q_util { |
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80 | u_int16_t s[4]; |
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81 | u_int32_t l[2]; |
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82 | u_int64_t q; |
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83 | }; |
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84 | |
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85 | u_short |
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86 | in_addword(u_short a, u_short b) |
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87 | { |
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88 | u_int64_t sum = a + b; |
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89 | |
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90 | ADDCARRY(sum); |
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91 | return (sum); |
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92 | } |
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93 | |
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94 | static |
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95 | uint64_t _do_cksum(void *addr, int len) |
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96 | { |
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97 | uint64_t sum; |
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98 | union q_util q_util; |
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99 | |
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100 | sum = do_cksum(addr, len); |
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101 | REDUCE32; |
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102 | return (sum); |
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103 | } |
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104 | |
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105 | u_short |
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106 | in_cksum_skip(struct mbuf *m, int len, int skip) |
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107 | { |
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108 | u_int64_t sum = 0; |
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109 | int mlen = 0; |
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110 | int clen = 0; |
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111 | caddr_t addr; |
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112 | union q_util q_util; |
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113 | union l_util l_util; |
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114 | |
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115 | len -= skip; |
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116 | for (; skip && m; m = m->m_next) { |
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117 | if (m->m_len > skip) { |
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118 | mlen = m->m_len - skip; |
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119 | addr = mtod(m, caddr_t) + skip; |
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120 | goto skip_start; |
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121 | } else { |
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122 | skip -= m->m_len; |
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123 | } |
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124 | } |
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125 | |
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126 | for (; m && len; m = m->m_next) { |
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127 | if (m->m_len == 0) |
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128 | continue; |
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129 | mlen = m->m_len; |
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130 | addr = mtod(m, caddr_t); |
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131 | skip_start: |
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132 | if (len < mlen) |
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133 | mlen = len; |
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134 | |
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135 | if ((clen ^ (int) addr) & 1) |
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136 | sum += _do_cksum(addr, mlen) << 8; |
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137 | else |
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138 | sum += _do_cksum(addr, mlen); |
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139 | |
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140 | clen += mlen; |
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141 | len -= mlen; |
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142 | } |
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143 | REDUCE16; |
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144 | return (~sum & 0xffff); |
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145 | } |
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146 | |
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147 | u_int in_cksum_hdr(const struct ip *ip) |
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148 | { |
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149 | u_int64_t sum = do_cksum(ip, sizeof(struct ip)); |
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150 | union q_util q_util; |
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151 | union l_util l_util; |
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152 | REDUCE16; |
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153 | return (~sum & 0xffff); |
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154 | } |
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