74 lines
1.9 KiB
C
74 lines
1.9 KiB
C
/* addr_and_mask.c
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* Routines to fetch IPv4 and IPv6 addresses from a tvbuff and then mask
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* out bits other than those covered by a prefix length
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*
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* $Id$
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include <stdlib.h>
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#include <string.h>
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#include "tvbuff.h"
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#include "addr_and_mask.h"
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/*
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* These routines return the length of the address in bytes on success
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* and -1 if the prefix length is too long.
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*/
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int
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ipv4_addr_and_mask(tvbuff_t *tvb, int offset, guint8 *addr, guint32 prefix_len)
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{
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guint32 addr_len;
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if (prefix_len > 32)
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return -1;
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addr_len = (prefix_len + 7) / 8;
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memset(addr, 0, 4);
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tvb_memcpy(tvb, addr, offset, addr_len);
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if (prefix_len % 8)
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addr[addr_len - 1] &= ((0xff00 >> (prefix_len % 8)) & 0xff);
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return addr_len;
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}
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int
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ipv6_addr_and_mask(tvbuff_t *tvb, int offset, struct e_in6_addr *addr,
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guint32 prefix_len)
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{
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guint32 addr_len;
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if (prefix_len > 128)
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return -1;
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addr_len = (prefix_len + 7) / 8;
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memset(addr->bytes, 0, 16);
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tvb_memcpy(tvb, addr->bytes, offset, addr_len);
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if (prefix_len % 8) {
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addr->bytes[addr_len - 1] &=
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((0xff00 >> (prefix_len % 8)) & 0xff);
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}
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return addr_len;
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}
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