[39e6e65a] | 1 | /* |
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| 2 | * Copyright (c) 1988, 1992, 1993 |
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| 3 | * The Regents of the University of California. All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * 1. Redistributions of source code must retain the above copyright |
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| 9 | * notice, this list of conditions and the following disclaimer. |
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| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
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| 11 | * notice, this list of conditions and the following disclaimer in the |
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| 12 | * documentation and/or other materials provided with the distribution. |
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| 13 | * 3. All advertising materials mentioning features or use of this software |
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| 14 | * must display the following acknowledgement: |
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| 15 | * This product includes software developed by the University of |
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| 16 | * California, Berkeley and its contributors. |
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| 17 | * 4. Neither the name of the University nor the names of its contributors |
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| 18 | * may be used to endorse or promote products derived from this software |
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| 19 | * without specific prior written permission. |
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| 20 | * |
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| 21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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| 22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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| 23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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| 24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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| 25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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| 26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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| 27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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| 28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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| 29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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| 30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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| 31 | * SUCH DAMAGE. |
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| 32 | * |
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| 33 | * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 |
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| 34 | * $Id$ |
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| 35 | */ |
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| 36 | |
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| 37 | #include <sys/param.h> |
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| 38 | #include <sys/mbuf.h> |
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| 39 | |
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| 40 | /* |
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[4de817d] | 41 | * Try to use a CPU specific version, then punt to the portable C one. |
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[39e6e65a] | 42 | */ |
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| 43 | |
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[4de817d] | 44 | #if (defined(__GNUC__) && (defined(__mc68000__) || defined(__m68k__))) |
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[39e6e65a] | 45 | |
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[4de817d] | 46 | #include "in_cksum_m68k.c" |
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[39e6e65a] | 47 | |
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[4de817d] | 48 | #elif (defined(__GNUC__) && defined(__i386__)) |
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[39e6e65a] | 49 | |
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[4de817d] | 50 | #include "in_cksum_i386.c" |
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[39e6e65a] | 51 | |
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[5d5f23b] | 52 | #elif (defined(__GNUC__) && defined(__PPC__)) |
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| 53 | |
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| 54 | #include "in_cksum_powerpc.c" |
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| 55 | |
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[39e6e65a] | 56 | #else |
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[4de817d] | 57 | |
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[39e6e65a] | 58 | /* |
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| 59 | * Checksum routine for Internet Protocol family headers (Portable Version). |
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| 60 | * |
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| 61 | * This routine is very heavily used in the network |
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| 62 | * code and should be modified for each CPU to be as fast as possible. |
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| 63 | */ |
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| 64 | |
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[617a1a2d] | 65 | #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) |
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| 66 | #define REDUCE \ |
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| 67 | {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);} |
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[39e6e65a] | 68 | |
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| 69 | int |
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| 70 | in_cksum(m, len) |
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| 71 | register struct mbuf *m; |
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| 72 | register int len; |
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| 73 | { |
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| 74 | register u_short *w; |
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| 75 | register int sum = 0; |
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| 76 | register int mlen = 0; |
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| 77 | int byte_swapped = 0; |
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| 78 | |
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| 79 | union { |
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| 80 | char c[2]; |
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| 81 | u_short s; |
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| 82 | } s_util; |
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| 83 | union { |
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| 84 | u_short s[2]; |
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| 85 | long l; |
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| 86 | } l_util; |
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| 87 | |
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| 88 | for (;m && len; m = m->m_next) { |
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| 89 | if (m->m_len == 0) |
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| 90 | continue; |
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| 91 | w = mtod(m, u_short *); |
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| 92 | if (mlen == -1) { |
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| 93 | /* |
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| 94 | * The first byte of this mbuf is the continuation |
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| 95 | * of a word spanning between this mbuf and the |
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| 96 | * last mbuf. |
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| 97 | * |
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| 98 | * s_util.c[0] is already saved when scanning previous |
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| 99 | * mbuf. |
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| 100 | */ |
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| 101 | s_util.c[1] = *(char *)w; |
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| 102 | sum += s_util.s; |
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| 103 | w = (u_short *)((char *)w + 1); |
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| 104 | mlen = m->m_len - 1; |
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| 105 | len--; |
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| 106 | } else |
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| 107 | mlen = m->m_len; |
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| 108 | if (len < mlen) |
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| 109 | mlen = len; |
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| 110 | len -= mlen; |
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| 111 | /* |
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| 112 | * Force to even boundary. |
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| 113 | */ |
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| 114 | if ((1 & (int) w) && (mlen > 0)) { |
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| 115 | REDUCE; |
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| 116 | sum <<= 8; |
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| 117 | s_util.c[0] = *(u_char *)w; |
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| 118 | w = (u_short *)((char *)w + 1); |
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| 119 | mlen--; |
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| 120 | byte_swapped = 1; |
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| 121 | } |
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| 122 | /* |
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| 123 | * Unroll the loop to make overhead from |
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| 124 | * branches &c small. |
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| 125 | */ |
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| 126 | while ((mlen -= 32) >= 0) { |
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| 127 | sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; |
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| 128 | sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; |
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| 129 | sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; |
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| 130 | sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; |
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| 131 | w += 16; |
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| 132 | } |
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| 133 | mlen += 32; |
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| 134 | while ((mlen -= 8) >= 0) { |
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| 135 | sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; |
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| 136 | w += 4; |
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| 137 | } |
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| 138 | mlen += 8; |
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| 139 | if (mlen == 0 && byte_swapped == 0) |
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| 140 | continue; |
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| 141 | REDUCE; |
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| 142 | while ((mlen -= 2) >= 0) { |
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| 143 | sum += *w++; |
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| 144 | } |
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| 145 | if (byte_swapped) { |
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| 146 | REDUCE; |
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| 147 | sum <<= 8; |
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| 148 | byte_swapped = 0; |
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| 149 | if (mlen == -1) { |
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| 150 | s_util.c[1] = *(char *)w; |
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| 151 | sum += s_util.s; |
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| 152 | mlen = 0; |
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| 153 | } else |
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| 154 | mlen = -1; |
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| 155 | } else if (mlen == -1) |
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| 156 | s_util.c[0] = *(char *)w; |
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| 157 | } |
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| 158 | if (len) |
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[887618b0] | 159 | puts("cksum: out of data"); |
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[39e6e65a] | 160 | if (mlen == -1) { |
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| 161 | /* The last mbuf has odd # of bytes. Follow the |
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| 162 | standard (the odd byte may be shifted left by 8 bits |
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| 163 | or not as determined by endian-ness of the machine) */ |
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| 164 | s_util.c[1] = 0; |
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| 165 | sum += s_util.s; |
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| 166 | } |
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| 167 | REDUCE; |
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| 168 | return (~sum & 0xffff); |
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| 169 | } |
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| 170 | #endif |
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