879 lines
27 KiB
C
879 lines
27 KiB
C
/*
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* dns64/dns64.c - DNS64 module
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*
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* Copyright (c) 2009, Viagénie. All rights reserved.
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*
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* This software is open source.
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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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*
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* Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* Neither the name of Viagénie nor the names of its contributors may
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* be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* \file
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*
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* This file contains a module that performs DNS64 query processing.
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*/
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#include "config.h"
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#include "dns64/dns64.h"
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#include "services/cache/dns.h"
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#include "services/cache/rrset.h"
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#include "util/config_file.h"
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#include "util/data/msgreply.h"
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#include "util/fptr_wlist.h"
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#include "util/net_help.h"
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#include "util/regional.h"
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/******************************************************************************
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* *
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* STATIC CONSTANTS *
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* *
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******************************************************************************/
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/**
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* This is the default DNS64 prefix that is used whent he dns64 module is listed
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* in module-config but when the dns64-prefix variable is not present.
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*/
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static const char DEFAULT_DNS64_PREFIX[] = "64:ff9b::/96";
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/**
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* Maximum length of a domain name in a PTR query in the .in-addr.arpa tree.
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*/
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#define MAX_PTR_QNAME_IPV4 30
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/**
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* Per-query module-specific state. This is usually a dynamically-allocated
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* structure, but in our case we only need to store one variable describing the
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* state the query is in. So we repurpose the minfo pointer by storing an
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* integer in there.
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*/
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enum dns64_qstate {
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DNS64_INTERNAL_QUERY, /**< Internally-generated query, no DNS64
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processing. */
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DNS64_NEW_QUERY, /**< Query for which we're the first module in
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line. */
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DNS64_SUBQUERY_FINISHED /**< Query for which we generated a sub-query, and
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for which this sub-query is finished. */
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};
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/******************************************************************************
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* *
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* STRUCTURES *
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* *
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******************************************************************************/
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/**
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* This structure contains module configuration information. One instance of
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* this structure exists per instance of the module. Normally there is only one
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* instance of the module.
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*/
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struct dns64_env {
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/**
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* DNS64 prefix address. We're using a full sockaddr instead of just an
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* in6_addr because we can reuse Unbound's generic string parsing functions.
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* It will always contain a sockaddr_in6, and only the sin6_addr member will
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* ever be used.
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*/
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struct sockaddr_storage prefix_addr;
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/**
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* This is always sizeof(sockaddr_in6).
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*/
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socklen_t prefix_addrlen;
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/**
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* This is the CIDR length of the prefix. It needs to be between 0 and 96.
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*/
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int prefix_net;
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};
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/******************************************************************************
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* *
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* UTILITY FUNCTIONS *
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* *
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******************************************************************************/
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/**
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* Generic macro for swapping two variables.
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*
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* \param t Type of the variables. (e.g. int)
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* \param a First variable.
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* \param b Second variable.
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*
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* \warning Do not attempt something foolish such as swap(int,a++,b++)!
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*/
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#define swap(t,a,b) do {t x = a; a = b; b = x;} while(0)
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/**
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* Reverses a string.
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*
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* \param begin Points to the first character of the string.
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* \param end Points one past the last character of the string.
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*/
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static void
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reverse(char* begin, char* end)
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{
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while ( begin < --end ) {
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swap(char, *begin, *end);
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++begin;
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}
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}
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/**
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* Convert an unsigned integer to a string. The point of this function is that
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* of being faster than sprintf().
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*
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* \param n The number to be converted.
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* \param s The result will be written here. Must be large enough, be careful!
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*
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* \return The number of characters written.
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*/
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static int
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uitoa(unsigned n, char* s)
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{
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char* ss = s;
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do {
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*ss++ = '0' + n % 10;
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} while (n /= 10);
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reverse(s, ss);
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return ss - s;
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}
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/**
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* Extract an IPv4 address embedded in the IPv6 address \a ipv6 at offset \a
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* offset (in bits). Note that bits are not necessarily aligned on bytes so we
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* need to be careful.
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*
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* \param ipv6 IPv6 address represented as a 128-bit array in big-endian
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* order.
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* \param offset Index of the MSB of the IPv4 address embedded in the IPv6
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* address.
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*/
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static uint32_t
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extract_ipv4(const uint8_t ipv6[16], const int offset)
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{
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uint32_t ipv4 = (uint32_t)ipv6[offset/8+0] << (24 + (offset%8))
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| (uint32_t)ipv6[offset/8+1] << (16 + (offset%8))
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| (uint32_t)ipv6[offset/8+2] << ( 8 + (offset%8))
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| (uint32_t)ipv6[offset/8+3] << ( 0 + (offset%8));
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if (offset/8+4 < 16)
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ipv4 |= (uint32_t)ipv6[offset/8+4] >> (8 - offset%8);
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return ipv4;
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}
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/**
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* Builds the PTR query name corresponding to an IPv4 address. For example,
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* given the number 3,464,175,361, this will build the string
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* "\03206\03123\0231\011\07in-addr\04arpa".
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*
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* \param ipv4 IPv4 address represented as an unsigned 32-bit number.
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* \param ptr The result will be written here. Must be large enough, be
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* careful!
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*
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* \return The number of characters written.
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*/
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static size_t
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ipv4_to_ptr(uint32_t ipv4, char ptr[MAX_PTR_QNAME_IPV4])
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{
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static const char IPV4_PTR_SUFFIX[] = "\07in-addr\04arpa";
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int i;
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char* c = ptr;
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for (i = 0; i < 4; ++i) {
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*c = uitoa((unsigned int)(ipv4 % 256), c + 1);
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c += *c + 1;
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ipv4 /= 256;
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}
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memmove(c, IPV4_PTR_SUFFIX, sizeof(IPV4_PTR_SUFFIX));
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return c + sizeof(IPV4_PTR_SUFFIX) - ptr;
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}
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/**
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* Converts an IPv6-related domain name string from a PTR query into an IPv6
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* address represented as a 128-bit array.
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*
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* \param ptr The domain name. (e.g. "\011[...]\010\012\016\012\03ip6\04arpa")
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* \param ipv6 The result will be written here, in network byte order.
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*
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* \return 1 on success, 0 on failure.
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*/
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static int
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ptr_to_ipv6(const char* ptr, uint8_t ipv6[16])
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{
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int i;
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for (i = 0; i < 64; i++) {
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int x;
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if (ptr[i++] != 1)
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return 0;
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if (ptr[i] >= '0' && ptr[i] <= '9') {
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x = ptr[i] - '0';
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} else if (ptr[i] >= 'a' && ptr[i] <= 'f') {
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x = ptr[i] - 'a' + 10;
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} else if (ptr[i] >= 'A' && ptr[i] <= 'F') {
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x = ptr[i] - 'A' + 10;
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} else {
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return 0;
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}
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ipv6[15-i/4] |= x << (2 * ((i-1) % 4));
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}
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return 1;
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}
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/**
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* Synthesize an IPv6 address based on an IPv4 address and the DNS64 prefix.
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*
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* \param prefix_addr DNS64 prefix address.
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* \param prefix_net CIDR length of the DNS64 prefix. Must be between 0 and 96.
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* \param a IPv4 address.
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* \param aaaa IPv6 address. The result will be written here.
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*/
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static void
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synthesize_aaaa(const uint8_t prefix_addr[16], int prefix_net,
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const uint8_t a[4], uint8_t aaaa[16])
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{
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memcpy(aaaa, prefix_addr, 16);
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aaaa[prefix_net/8+0] |= a[0] >> (0+prefix_net%8);
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aaaa[prefix_net/8+1] |= a[0] << (8-prefix_net%8);
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aaaa[prefix_net/8+1] |= a[1] >> (0+prefix_net%8);
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aaaa[prefix_net/8+2] |= a[1] << (8-prefix_net%8);
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aaaa[prefix_net/8+2] |= a[2] >> (0+prefix_net%8);
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aaaa[prefix_net/8+3] |= a[2] << (8-prefix_net%8);
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aaaa[prefix_net/8+3] |= a[3] >> (0+prefix_net%8);
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if (prefix_net/8+4 < 16) /* <-- my beautiful symmetry is destroyed! */
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aaaa[prefix_net/8+4] |= a[3] << (8-prefix_net%8);
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}
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/******************************************************************************
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* *
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* DNS64 MODULE FUNCTIONS *
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* *
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******************************************************************************/
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/**
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* This function applies the configuration found in the parsed configuration
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* file \a cfg to this instance of the dns64 module. Currently only the DNS64
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* prefix (a.k.a. Pref64) is configurable.
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*
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* \param dns64_env Module-specific global parameters.
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* \param cfg Parsed configuration file.
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*/
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static int
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dns64_apply_cfg(struct dns64_env* dns64_env, struct config_file* cfg)
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{
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verbose(VERB_ALGO, "dns64-prefix: %s", cfg->dns64_prefix);
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if (!netblockstrtoaddr(cfg->dns64_prefix ? cfg->dns64_prefix :
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DEFAULT_DNS64_PREFIX, 0, &dns64_env->prefix_addr,
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&dns64_env->prefix_addrlen, &dns64_env->prefix_net)) {
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log_err("cannot parse dns64-prefix netblock: %s", cfg->dns64_prefix);
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return 0;
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}
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if (!addr_is_ip6(&dns64_env->prefix_addr, dns64_env->prefix_addrlen)) {
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log_err("dns64_prefix is not IPv6: %s", cfg->dns64_prefix);
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return 0;
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}
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if (dns64_env->prefix_net < 0 || dns64_env->prefix_net > 96) {
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log_err("dns64-prefix length it not between 0 and 96: %s",
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cfg->dns64_prefix);
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return 0;
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}
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return 1;
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}
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/**
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* Initializes this instance of the dns64 module.
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*
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* \param env Global state of all module instances.
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* \param id This instance's ID number.
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*/
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int
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dns64_init(struct module_env* env, int id)
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{
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struct dns64_env* dns64_env =
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(struct dns64_env*)calloc(1, sizeof(struct dns64_env));
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if (!dns64_env) {
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log_err("malloc failure");
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return 0;
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}
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env->modinfo[id] = (void*)dns64_env;
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if (!dns64_apply_cfg(dns64_env, env->cfg)) {
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log_err("dns64: could not apply configuration settings.");
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return 0;
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}
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return 1;
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}
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/**
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* Deinitializes this instance of the dns64 module.
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*
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* \param env Global state of all module instances.
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* \param id This instance's ID number.
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*/
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void
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dns64_deinit(struct module_env* env, int id)
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{
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if (!env)
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return;
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free(env->modinfo[id]);
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env->modinfo[id] = NULL;
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}
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/**
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* Handle PTR queries for IPv6 addresses. If the address belongs to the DNS64
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* prefix, we must do a PTR query for the corresponding IPv4 address instead.
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*
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* \param qstate Query state structure.
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* \param id This module instance's ID number.
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*
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* \return The new state of the query.
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*/
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static enum module_ext_state
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handle_ipv6_ptr(struct module_qstate* qstate, int id)
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{
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struct dns64_env* dns64_env = (struct dns64_env*)qstate->env->modinfo[id];
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struct module_qstate* subq = NULL;
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struct query_info qinfo;
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struct sockaddr_in6 sin6;
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/* Convert the PTR query string to an IPv6 address. */
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memset(&sin6, 0, sizeof(sin6));
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sin6.sin6_family = AF_INET6;
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if (!ptr_to_ipv6((char*)qstate->qinfo.qname, sin6.sin6_addr.s6_addr))
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return module_wait_module; /* Let other module handle this. */
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/*
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* If this IPv6 address is not part of our DNS64 prefix, then we don't need
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* to do anything. Let another module handle the query.
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*/
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if (addr_in_common((struct sockaddr_storage*)&sin6, 128,
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&dns64_env->prefix_addr, dns64_env->prefix_net,
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(socklen_t)sizeof(sin6)) != dns64_env->prefix_net)
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return module_wait_module;
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verbose(VERB_ALGO, "dns64: rewrite PTR record");
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/*
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* Create a new PTR query info for the domain name corresponding to the IPv4
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* address corresponding to the IPv6 address corresponding to the original
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* PTR query domain name.
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*/
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qinfo = qstate->qinfo;
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if (!(qinfo.qname = regional_alloc(qstate->region, MAX_PTR_QNAME_IPV4)))
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return module_error;
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qinfo.qname_len = ipv4_to_ptr(extract_ipv4(sin6.sin6_addr.s6_addr,
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dns64_env->prefix_net), (char*)qinfo.qname);
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/* Create the new sub-query. */
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fptr_ok(fptr_whitelist_modenv_attach_sub(qstate->env->attach_sub));
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if(!(*qstate->env->attach_sub)(qstate, &qinfo, qstate->query_flags, 0, 0,
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&subq))
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return module_error;
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if (subq) {
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subq->curmod = id;
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subq->ext_state[id] = module_state_initial;
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subq->minfo[id] = NULL;
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}
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return module_wait_subquery;
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}
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/** allocate (special) rrset keys, return 0 on error */
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static int
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repinfo_alloc_rrset_keys(struct reply_info* rep,
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struct regional* region)
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{
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size_t i;
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for(i=0; i<rep->rrset_count; i++) {
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if(region) {
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rep->rrsets[i] = (struct ub_packed_rrset_key*)
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regional_alloc(region,
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sizeof(struct ub_packed_rrset_key));
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if(rep->rrsets[i]) {
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memset(rep->rrsets[i], 0,
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sizeof(struct ub_packed_rrset_key));
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rep->rrsets[i]->entry.key = rep->rrsets[i];
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}
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}
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else return 0;/* rep->rrsets[i] = alloc_special_obtain(alloc);*/
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if(!rep->rrsets[i])
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return 0;
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rep->rrsets[i]->entry.data = NULL;
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}
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return 1;
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}
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static enum module_ext_state
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generate_type_A_query(struct module_qstate* qstate, int id)
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{
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struct module_qstate* subq = NULL;
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struct query_info qinfo;
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verbose(VERB_ALGO, "dns64: query A record");
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/* Create a new query info. */
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qinfo = qstate->qinfo;
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qinfo.qtype = LDNS_RR_TYPE_A;
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/* Start the sub-query. */
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fptr_ok(fptr_whitelist_modenv_attach_sub(qstate->env->attach_sub));
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if(!(*qstate->env->attach_sub)(qstate, &qinfo, qstate->query_flags, 0,
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0, &subq))
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{
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verbose(VERB_ALGO, "dns64: sub-query creation failed");
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return module_error;
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}
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if (subq) {
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subq->curmod = id;
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subq->ext_state[id] = module_state_initial;
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subq->minfo[id] = NULL;
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}
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return module_wait_subquery;
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}
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/**
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* Handles the "pass" event for a query. This event is received when a new query
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* is received by this module. The query may have been generated internally by
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* another module, in which case we don't want to do any special processing
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* (this is an interesting discussion topic), or it may be brand new, e.g.
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* received over a socket, in which case we do want to apply DNS64 processing.
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*
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* \param qstate A structure representing the state of the query that has just
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* received the "pass" event.
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* \param id This module's instance ID.
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*
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* \return The new state of the query.
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*/
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static enum module_ext_state
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handle_event_pass(struct module_qstate* qstate, int id)
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{
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if ((uintptr_t)qstate->minfo[id] == DNS64_NEW_QUERY
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&& qstate->qinfo.qtype == LDNS_RR_TYPE_PTR
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&& qstate->qinfo.qname_len == 74
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&& !strcmp((char*)&qstate->qinfo.qname[64], "\03ip6\04arpa"))
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/* Handle PTR queries for IPv6 addresses. */
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|
return handle_ipv6_ptr(qstate, id);
|
|
|
|
if (qstate->env->cfg->dns64_synthall &&
|
|
(uintptr_t)qstate->minfo[id] == DNS64_NEW_QUERY
|
|
&& qstate->qinfo.qtype == LDNS_RR_TYPE_AAAA)
|
|
return generate_type_A_query(qstate, id);
|
|
|
|
/* We are finished when our sub-query is finished. */
|
|
if ((uintptr_t)qstate->minfo[id] == DNS64_SUBQUERY_FINISHED)
|
|
return module_finished;
|
|
|
|
/* Otherwise, pass request to next module. */
|
|
verbose(VERB_ALGO, "dns64: pass to next module");
|
|
return module_wait_module;
|
|
}
|
|
|
|
/**
|
|
* Handles the "done" event for a query. We need to analyze the response and
|
|
* maybe issue a new sub-query for the A record.
|
|
*
|
|
* \param qstate A structure representing the state of the query that has just
|
|
* received the "pass" event.
|
|
* \param id This module's instance ID.
|
|
*
|
|
* \return The new state of the query.
|
|
*/
|
|
static enum module_ext_state
|
|
handle_event_moddone(struct module_qstate* qstate, int id)
|
|
{
|
|
/*
|
|
* In many cases we have nothing special to do. From most to least common:
|
|
*
|
|
* - An internal query.
|
|
* - A query for a record type other than AAAA.
|
|
* - CD FLAG was set on querier
|
|
* - An AAAA query for which an error was returned.(qstate.return_rcode)
|
|
* -> treated as servfail thus synthesize (sec 5.1.3 6147), thus
|
|
* synthesize in (sec 5.1.2 of RFC6147).
|
|
* - A successful AAAA query with an answer.
|
|
*/
|
|
if ( (enum dns64_qstate)qstate->minfo[id] == DNS64_INTERNAL_QUERY
|
|
|| qstate->qinfo.qtype != LDNS_RR_TYPE_AAAA
|
|
|| (qstate->query_flags & BIT_CD)
|
|
|| (qstate->return_msg &&
|
|
qstate->return_msg->rep &&
|
|
reply_find_answer_rrset(&qstate->qinfo,
|
|
qstate->return_msg->rep)))
|
|
return module_finished;
|
|
|
|
/* So, this is a AAAA noerror/nodata answer */
|
|
return generate_type_A_query(qstate, id);
|
|
}
|
|
|
|
/**
|
|
* This is the module's main() function. It gets called each time a query
|
|
* receives an event which we may need to handle. We respond by updating the
|
|
* state of the query.
|
|
*
|
|
* \param qstate Structure containing the state of the query.
|
|
* \param event Event that has just been received.
|
|
* \param id This module's instance ID.
|
|
* \param outbound State of a DNS query on an authoritative server. We never do
|
|
* our own queries ourselves (other modules do it for us), so
|
|
* this is unused.
|
|
*/
|
|
void
|
|
dns64_operate(struct module_qstate* qstate, enum module_ev event, int id,
|
|
struct outbound_entry* outbound)
|
|
{
|
|
(void)outbound;
|
|
verbose(VERB_QUERY, "dns64[module %d] operate: extstate:%s event:%s",
|
|
id, strextstate(qstate->ext_state[id]),
|
|
strmodulevent(event));
|
|
log_query_info(VERB_QUERY, "dns64 operate: query", &qstate->qinfo);
|
|
|
|
switch(event) {
|
|
case module_event_new:
|
|
/* Tag this query as being new and fall through. */
|
|
qstate->minfo[id] = (void*)DNS64_NEW_QUERY;
|
|
case module_event_pass:
|
|
qstate->ext_state[id] = handle_event_pass(qstate, id);
|
|
break;
|
|
case module_event_moddone:
|
|
qstate->ext_state[id] = handle_event_moddone(qstate, id);
|
|
break;
|
|
default:
|
|
qstate->ext_state[id] = module_finished;
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void
|
|
dns64_synth_aaaa_data(const struct ub_packed_rrset_key* fk,
|
|
const struct packed_rrset_data* fd,
|
|
struct ub_packed_rrset_key *dk,
|
|
struct packed_rrset_data **dd_out, struct regional *region,
|
|
struct dns64_env* dns64_env )
|
|
{
|
|
struct packed_rrset_data *dd;
|
|
size_t i;
|
|
/*
|
|
* Create synthesized AAAA RR set data. We need to allocated extra memory
|
|
* for the RRs themselves. Each RR has a length, TTL, pointer to wireformat
|
|
* data, 2 bytes of data length, and 16 bytes of IPv6 address.
|
|
*/
|
|
if(fd->count > RR_COUNT_MAX) {
|
|
*dd_out = NULL;
|
|
return; /* integer overflow protection in alloc */
|
|
}
|
|
if (!(dd = *dd_out = regional_alloc(region,
|
|
sizeof(struct packed_rrset_data)
|
|
+ fd->count * (sizeof(size_t) + sizeof(time_t) +
|
|
sizeof(uint8_t*) + 2 + 16)))) {
|
|
log_err("out of memory");
|
|
return;
|
|
}
|
|
|
|
/* Copy attributes from A RR set. */
|
|
dd->ttl = fd->ttl;
|
|
dd->count = fd->count;
|
|
dd->rrsig_count = 0;
|
|
dd->trust = fd->trust;
|
|
dd->security = fd->security;
|
|
|
|
/*
|
|
* Synthesize AAAA records. Adjust pointers in structure.
|
|
*/
|
|
dd->rr_len =
|
|
(size_t*)((uint8_t*)dd + sizeof(struct packed_rrset_data));
|
|
dd->rr_data = (uint8_t**)&dd->rr_len[dd->count];
|
|
dd->rr_ttl = (time_t*)&dd->rr_data[dd->count];
|
|
for(i = 0; i < fd->count; ++i) {
|
|
if (fd->rr_len[i] != 6 || fd->rr_data[i][0] != 0
|
|
|| fd->rr_data[i][1] != 4) {
|
|
*dd_out = NULL;
|
|
return;
|
|
}
|
|
dd->rr_len[i] = 18;
|
|
dd->rr_data[i] =
|
|
(uint8_t*)&dd->rr_ttl[dd->count] + 18*i;
|
|
dd->rr_data[i][0] = 0;
|
|
dd->rr_data[i][1] = 16;
|
|
synthesize_aaaa(
|
|
((struct sockaddr_in6*)&dns64_env->prefix_addr)->sin6_addr.s6_addr,
|
|
dns64_env->prefix_net, &fd->rr_data[i][2],
|
|
&dd->rr_data[i][2] );
|
|
dd->rr_ttl[i] = fd->rr_ttl[i];
|
|
}
|
|
|
|
/*
|
|
* Create synthesized AAAA RR set key. This is mostly just bookkeeping,
|
|
* nothing interesting here.
|
|
*/
|
|
if(!dk) {
|
|
log_err("no key");
|
|
*dd_out = NULL;
|
|
return;
|
|
}
|
|
|
|
dk->rk.dname = (uint8_t*)regional_alloc_init(region,
|
|
fk->rk.dname, fk->rk.dname_len);
|
|
|
|
if(!dk->rk.dname) {
|
|
log_err("out of memory");
|
|
*dd_out = NULL;
|
|
return;
|
|
}
|
|
|
|
dk->rk.type = htons(LDNS_RR_TYPE_AAAA);
|
|
memset(&dk->entry, 0, sizeof(dk->entry));
|
|
dk->entry.key = dk;
|
|
dk->entry.hash = rrset_key_hash(&dk->rk);
|
|
dk->entry.data = dd;
|
|
|
|
}
|
|
|
|
/**
|
|
* Synthesize an AAAA RR set from an A sub-query's answer and add it to the
|
|
* original empty response.
|
|
*
|
|
* \param id This module's instance ID.
|
|
* \param super Original AAAA query.
|
|
* \param qstate A query.
|
|
*/
|
|
static void
|
|
dns64_adjust_a(int id, struct module_qstate* super, struct module_qstate* qstate)
|
|
{
|
|
struct dns64_env* dns64_env = (struct dns64_env*)super->env->modinfo[id];
|
|
struct reply_info *rep, *cp;
|
|
size_t i, s;
|
|
struct packed_rrset_data* fd, *dd;
|
|
struct ub_packed_rrset_key* fk, *dk;
|
|
|
|
verbose(VERB_ALGO, "converting A answers to AAAA answers");
|
|
|
|
log_assert(super->region);
|
|
log_assert(qstate->return_msg);
|
|
log_assert(qstate->return_msg->rep);
|
|
|
|
/* If dns64-synthall is enabled, return_msg is not initialized */
|
|
if(!super->return_msg) {
|
|
super->return_msg = (struct dns_msg*)regional_alloc(
|
|
super->region, sizeof(struct dns_msg));
|
|
if(!super->return_msg)
|
|
return;
|
|
memset(super->return_msg, 0, sizeof(*super->return_msg));
|
|
super->return_msg->qinfo = super->qinfo;
|
|
}
|
|
|
|
rep = qstate->return_msg->rep;
|
|
|
|
/*
|
|
* Build the actual reply.
|
|
*/
|
|
cp = construct_reply_info_base(super->region, rep->flags, rep->qdcount,
|
|
rep->ttl, rep->prefetch_ttl, rep->an_numrrsets, rep->ns_numrrsets,
|
|
rep->ar_numrrsets, rep->rrset_count, rep->security);
|
|
if(!cp)
|
|
return;
|
|
|
|
/* allocate ub_key structures special or not */
|
|
if(!repinfo_alloc_rrset_keys(cp, super->region)) {
|
|
return;
|
|
}
|
|
|
|
/* copy everything and replace A by AAAA */
|
|
for(i=0; i<cp->rrset_count; i++) {
|
|
fk = rep->rrsets[i];
|
|
dk = cp->rrsets[i];
|
|
fd = (struct packed_rrset_data*)fk->entry.data;
|
|
dk->rk = fk->rk;
|
|
dk->id = fk->id;
|
|
|
|
if(i<rep->an_numrrsets && fk->rk.type == htons(LDNS_RR_TYPE_A)) {
|
|
/* also sets dk->entry.hash */
|
|
dns64_synth_aaaa_data(fk, fd, dk, &dd, super->region, dns64_env);
|
|
if(!dd)
|
|
return;
|
|
/* Delete negative AAAA record from cache stored by
|
|
* the iterator module */
|
|
rrset_cache_remove(super->env->rrset_cache, dk->rk.dname,
|
|
dk->rk.dname_len, LDNS_RR_TYPE_AAAA,
|
|
LDNS_RR_CLASS_IN, 0);
|
|
} else {
|
|
dk->entry.hash = fk->entry.hash;
|
|
dk->rk.dname = (uint8_t*)regional_alloc_init(super->region,
|
|
fk->rk.dname, fk->rk.dname_len);
|
|
|
|
if(!dk->rk.dname)
|
|
return;
|
|
|
|
s = packed_rrset_sizeof(fd);
|
|
dd = (struct packed_rrset_data*)regional_alloc_init(
|
|
super->region, fd, s);
|
|
|
|
if(!dd)
|
|
return;
|
|
}
|
|
|
|
packed_rrset_ptr_fixup(dd);
|
|
dk->entry.data = (void*)dd;
|
|
}
|
|
|
|
/* Commit changes. */
|
|
super->return_msg->rep = cp;
|
|
}
|
|
|
|
/**
|
|
* Generate a response for the original IPv6 PTR query based on an IPv4 PTR
|
|
* sub-query's response.
|
|
*
|
|
* \param qstate IPv4 PTR sub-query.
|
|
* \param super Original IPv6 PTR query.
|
|
*/
|
|
static void
|
|
dns64_adjust_ptr(struct module_qstate* qstate, struct module_qstate* super)
|
|
{
|
|
struct ub_packed_rrset_key* answer;
|
|
|
|
verbose(VERB_ALGO, "adjusting PTR reply");
|
|
|
|
/* Copy the sub-query's reply to the parent. */
|
|
if (!(super->return_msg = (struct dns_msg*)regional_alloc(super->region,
|
|
sizeof(struct dns_msg))))
|
|
return;
|
|
super->return_msg->qinfo = super->qinfo;
|
|
super->return_msg->rep = reply_info_copy(qstate->return_msg->rep, NULL,
|
|
super->region);
|
|
|
|
/*
|
|
* Adjust the domain name of the answer RR set so that it matches the
|
|
* initial query's domain name.
|
|
*/
|
|
answer = reply_find_answer_rrset(&qstate->qinfo, super->return_msg->rep);
|
|
log_assert(answer);
|
|
answer->rk.dname = super->qinfo.qname;
|
|
answer->rk.dname_len = super->qinfo.qname_len;
|
|
}
|
|
|
|
/**
|
|
* This function is called when a sub-query finishes to inform the parent query.
|
|
*
|
|
* We issue two kinds of sub-queries: PTR and A.
|
|
*
|
|
* \param qstate State of the sub-query.
|
|
* \param id This module's instance ID.
|
|
* \param super State of the super-query.
|
|
*/
|
|
void
|
|
dns64_inform_super(struct module_qstate* qstate, int id,
|
|
struct module_qstate* super)
|
|
{
|
|
log_query_info(VERB_ALGO, "dns64: inform_super, sub is",
|
|
&qstate->qinfo);
|
|
log_query_info(VERB_ALGO, "super is", &super->qinfo);
|
|
|
|
/*
|
|
* Signal that the sub-query is finished, no matter whether we are
|
|
* successful or not. This lets the state machine terminate.
|
|
*/
|
|
super->minfo[id] = (void*)DNS64_SUBQUERY_FINISHED;
|
|
|
|
/* If there is no successful answer, we're done. */
|
|
if (qstate->return_rcode != LDNS_RCODE_NOERROR
|
|
|| !qstate->return_msg
|
|
|| !qstate->return_msg->rep
|
|
|| !reply_find_answer_rrset(&qstate->qinfo,
|
|
qstate->return_msg->rep))
|
|
return;
|
|
|
|
/* Generate a response suitable for the original query. */
|
|
if (qstate->qinfo.qtype == LDNS_RR_TYPE_A) {
|
|
dns64_adjust_a(id, super, qstate);
|
|
} else {
|
|
log_assert(qstate->qinfo.qtype == LDNS_RR_TYPE_PTR);
|
|
dns64_adjust_ptr(qstate, super);
|
|
}
|
|
|
|
/* Store the generated response in cache. */
|
|
if (!dns_cache_store(super->env, &super->qinfo, super->return_msg->rep,
|
|
0, 0, 0, NULL, super->query_flags))
|
|
log_err("out of memory");
|
|
}
|
|
|
|
/**
|
|
* Clear module-specific data from query state. Since we do not allocate memory,
|
|
* it's just a matter of setting a pointer to NULL.
|
|
*
|
|
* \param qstate Query state.
|
|
* \param id This module's instance ID.
|
|
*/
|
|
void
|
|
dns64_clear(struct module_qstate* qstate, int id)
|
|
{
|
|
qstate->minfo[id] = NULL;
|
|
}
|
|
|
|
/**
|
|
* Returns the amount of global memory that this module uses, not including
|
|
* per-query data.
|
|
*
|
|
* \param env Module environment.
|
|
* \param id This module's instance ID.
|
|
*/
|
|
size_t
|
|
dns64_get_mem(struct module_env* env, int id)
|
|
{
|
|
struct dns64_env* dns64_env = (struct dns64_env*)env->modinfo[id];
|
|
if (!dns64_env)
|
|
return 0;
|
|
return sizeof(*dns64_env);
|
|
}
|
|
|
|
/**
|
|
* The dns64 function block.
|
|
*/
|
|
static struct module_func_block dns64_block = {
|
|
"dns64",
|
|
&dns64_init, &dns64_deinit, &dns64_operate, &dns64_inform_super,
|
|
&dns64_clear, &dns64_get_mem
|
|
};
|
|
|
|
/**
|
|
* Function for returning the above function block.
|
|
*/
|
|
struct module_func_block *
|
|
dns64_get_funcblock(void)
|
|
{
|
|
return &dns64_block;
|
|
}
|