0100 ˆ¾Â ƒh¹ÀÅ1:7 ˆÃ „e÷ÿÁÀÅ?÷/* * Copyright (C) Internet Systems Consortium, Inc. ("ISC") * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. * * See the COPYRIGHT file distributed with this work for additional * information regarding copyright ownership. */ #include "types.h" #ifndef DNS_MESSAGE_H #define DNS_MESSAGE_H 1 /*** *** Imports ***/ #include #include #include #include #include #include #include #include /*! \file dns/message.h * \brief Message Handling Module * * How this beast works: * * When a dns message is received in a buffer, dns_message_parse() is called * on the memory region. Various items are checked including the format * of the message (if counts are right, if counts consume the entire sections, * and if sections consume the entire message) and known pseudo-RRs in the * additional data section are analyzed and removed. * * TSIG checking is also done at this layer, and any DNSSEC transaction * signatures should also be checked here. * * Notes on using the gettemp*() and puttemp*() functions: * * These functions return items (names, rdatasets, etc) allocated from some * internal state of the dns_message_t. * * Names and rdatasets must be put back into the dns_message_t in * one of two ways. Assume a name was allocated via * dns_message_gettempname(): * *\li (1) insert it into a section, using dns_message_addname(). * *\li (2) return it to the message using dns_message_puttempname(). * * The same applies to rdatasets. * * On the other hand, offsets, rdatalists and rdatas allocated using * dns_message_gettemp*() will always be freed automatically * when the message is reset or destroyed; calling dns_message_puttemp*() * on rdatalists and rdatas is optional and serves only to enable the item * to be reused multiple times during the lifetime of the message; offsets * cannot be reused. * * Buffers allocated using isc_buffer_allocate() can be automatically freed * as well by giving the buffer to the message using dns_message_takebuffer(). * Doing this will cause the buffer to be freed using isc_buffer_free() * when the section lists are cleared, such as in a reset or in a destroy. * Since the buffer itself exists until the message is destroyed, this sort * of code can be written: * * \code * buffer = isc_buffer_allocate(mctx, 512); * name = NULL; * name = dns_message_gettempname(message, &name); * dns_name_init(name, NULL); * result = dns_name_fromtext(name, &source, dns_rootname, 0, buffer); * dns_message_takebuffer(message, &buffer); * \endcode * * * TODO: * * XXX Needed: ways to set and retrieve EDNS information, add rdata to a * section, move rdata from one section to another, remove rdata, etc. */ #define DNS_MESSAGEFLAG_QR 0x8000U #define DNS_MESSAGEFLAG_AA 0x0400U #define DNS_MESSAGEFLAG_TC 0x0200U #define DNS_MESSAGEFLAG_RD 0x0100U #define DNS_MESSAGEFLAG_RA 0x0080U #define DNS_MESSAGEFLAG_AD 0x0020U #define DNS_MESSAGEFLAG_CD 0x0010U /*%< EDNS0 extended message flags */ #define DNS_MESSAGEEXTFLAG_DO 0x8000U /*%< EDNS0 extended OPT codes */ #define DNS_OPT_NSID 3 /*%< NSID opt code */ #define DNS_OPT_CLIENT_SUBNET 8 /*%< client subnet opt code */ #define DNS_OPT_EXPIRE 9 /*%< EXPIRE opt code */ #define DNS_OPT_COOKIE 10 /*%< COOKIE opt code */ #define DNS_OPT_PAD 12 /*%< PAD opt code */ #define DNS_OPT_KEY_TAG 14 /*%< Key tag opt code */ /*%< Experimental options [65001...65534] as per RFC6891 */ /*%< The number of EDNS options we know about. */ #define DNS_EDNSOPTIONS 5 #define DNS_MESSAGE_REPLYPRESERVE (DNS_MESSAGEFLAG_RD|DNS_MESSAGEFLAG_CD) #define DNS_MESSAGEEXTFLAG_REPLYPRESERVE (DNS_MESSAGEEXTFLAG_DO) #define DNS_MESSAGE_HEADERLEN 12 /*%< 6 isc_uint16_t's */ #define DNS_MESSAGE_MAGIC ISC_MAGI