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feat(lisp/dns): Support CNAME & NS record RDATAs

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This commit is contained in:
Vincent Ambo 2020-01-27 00:47:45 +00:00
parent a8c9058a58
commit 90dd824606
2 changed files with 65 additions and 379 deletions
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8
lisp/dns/client.lisp
View file

@ -74,3 +74,11 @@
(defun lookup-mx (name &key (doh-url *doh-base-url*))
"Look up the MX records at NAME."
(lookup-generic name "MX" doh-url))
(defun lookup-cname (name &key (doh-url *doh-base-url*))
"Look up the CNAME records at NAME."
(lookup-generic name "CNAME" doh-url))
(defun lookup-ns (name &key (doh-url *doh-base-url*))
"Look up the NS records at NAME."
(lookup-generic name "NS" doh-url))

436
lisp/dns/message.lisp
View file

@ -1,80 +1,5 @@
(in-package :dns)
;; 3.2.2. TYPE values
;; TYPE fields are used in resource records. Note that these types are a
;; subset of QTYPEs.
;; TYPE value and meaning
;; A 1 a host address
;; NS 2 an authoritative name server
;; MD 3 a mail destination (Obsolete - use MX)
;; MF 4 a mail forwarder (Obsolete - use MX)
;; CNAME 5 the canonical name for an alias
;; SOA 6 marks the start of a zone of authority
;; MB 7 a mailbox domain name (EXPERIMENTAL)
;; MG 8 a mail group member (EXPERIMENTAL)
;; MR 9 a mail rename domain name (EXPERIMENTAL)
;; NULL 10 a null RR (EXPERIMENTAL)
;; WKS 11 a well known service description
;; PTR 12 a domain name pointer
;; HINFO 13 host information
;; MINFO 14 mailbox or mail list information
;; MX 15 mail exchange
;; TXT 16 text strings
;; 3.2.3. QTYPE values
;; QTYPE fields appear in the question part of a query. QTYPES are a
;; superset of TYPEs, hence all TYPEs are valid QTYPEs. In addition, the
;; following QTYPEs are defined:
;; AXFR 252 A request for a transfer of an entire zone
;; MAILB 253 A request for mailbox-related records (MB, MG or MR)
;; MAILA 254 A request for mail agent RRs (Obsolete - see MX)
;; * 255 A request for all records
;; 3.2.4. CLASS values
;; CLASS fields appear in resource records. The following CLASS mnemonics
;; and values are defined:
;; IN 1 the Internet
;; CS 2 the CSNET class (Obsolete - used only for examples in
;; some obsolete RFCs)
;; CH 3 the CHAOS class
;; HS 4 Hesiod [Dyer 87]
;; 3.2.5. QCLASS values
;; QCLASS fields appear in the question section of a query. QCLASS values
;; are a superset of CLASS values; every CLASS is a valid QCLASS. In
;; addition to CLASS values, the following QCLASSes are defined:
;; * 255 any class
;; 3.3. Standard RRs
;; The following RR definitions are expected to occur, at least
@ -89,22 +14,6 @@
;; is treated as binary information, and can be up to 256 characters in
;; length (including the length octet).
;; 3.3.1. CNAME RDATA format
;; +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
;; / CNAME /
;; / /
;; +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
;; where:
;; CNAME A <domain-name> which specifies the canonical or primary
;; name for the owner. The owner name is an alias.
;; CNAME RRs cause no additional section processing, but name servers may
;; choose to restart the query at the canonical name in certain cases. See
;; the description of name server logic in [RFC-1034] for details.
;; 3.3.11. NS RDATA format
@ -220,255 +129,11 @@
;; where:
;; TXT-DATA One or more <character-string>s.
;; TXT-DATA
;; TXT RRs are used to hold descriptive text. The semantics of the text
;; depends on the domain where it is found.
;; 3.4. Internet specific RRs
;; 3.4.1. A RDATA format
;; +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
;; | ADDRESS |
;; +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
;; where:
;; ADDRESS A 32 bit Internet address.
;; Hosts that have multiple Internet addresses will have multiple A
;; records.
;; A records cause no additional section processing. The RDATA section of
;; an A line in a master file is an Internet address expressed as four
;; decimal numbers separated by dots without any imbedded spaces (e.g.,
;; "10.2.0.52" or "192.0.5.6").
;; 3.4.2. WKS RDATA format
;; +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
;; | ADDRESS |
;; +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
;; | PROTOCOL | |
;; +--+--+--+--+--+--+--+--+ |
;; | |
;; / <BIT MAP> /
;; / /
;; +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
;; where:
;; ADDRESS An 32 bit Internet address
;; PROTOCOL An 8 bit IP protocol number
;; <BIT MAP> A variable length bit map. The bit map must be a
;; multiple of 8 bits long.
;; The WKS record is used to describe the well known services supported by
;; a particular protocol on a particular internet address. The PROTOCOL
;; field specifies an IP protocol number, and the bit map has one bit per
;; port of the specified protocol. The first bit corresponds to port 0,
;; the second to port 1, etc. If the bit map does not include a bit for a
;; protocol of interest, that bit is assumed zero. The appropriate values
;; and mnemonics for ports and protocols are specified in [RFC-1010].
;; For example, if PROTOCOL=TCP (6), the 26th bit corresponds to TCP port
;; 25 (SMTP). If this bit is set, a SMTP server should be listening on TCP
;; port 25; if zero, SMTP service is not supported on the specified
;; address.
;; The purpose of WKS RRs is to provide availability information for
;; servers for TCP and UDP. If a server supports both TCP and UDP, or has
;; multiple Internet addresses, then multiple WKS RRs are used.
;; WKS RRs cause no additional section processing.
;; In master files, both ports and protocols are expressed using mnemonics
;; or decimal numbers.
;; 3.5. IN-ADDR.ARPA domain
;; The Internet uses a special domain to support gateway location and
;; Internet address to host mapping. Other classes may employ a similar
;; strategy in other domains. The intent of this domain is to provide a
;; guaranteed method to perform host address to host name mapping, and to
;; facilitate queries to locate all gateways on a particular network in the
;; Internet.
;; Note that both of these services are similar to functions that could be
;; performed by inverse queries; the difference is that this part of the
;; domain name space is structured according to address, and hence can
;; guarantee that the appropriate data can be located without an exhaustive
;; search of the domain space.
;; The domain begins at IN-ADDR.ARPA and has a substructure which follows
;; the Internet addressing structure.
;; Domain names in the IN-ADDR.ARPA domain are defined to have up to four
;; labels in addition to the IN-ADDR.ARPA suffix. Each label represents
;; one octet of an Internet address, and is expressed as a character string
;; for a decimal value in the range 0-255 (with leading zeros omitted
;; except in the case of a zero octet which is represented by a single
;; zero).
;; Host addresses are represented by domain names that have all four labels
;; specified. Thus data for Internet address 10.2.0.52 is located at
;; domain name 52.0.2.10.IN-ADDR.ARPA. The reversal, though awkward to
;; read, allows zones to be delegated which are exactly one network of
;; address space. For example, 10.IN-ADDR.ARPA can be a zone containing
;; data for the ARPANET, while 26.IN-ADDR.ARPA can be a separate zone for
;; MILNET. Address nodes are used to hold pointers to primary host names
;; in the normal domain space.
;; Network numbers correspond to some non-terminal nodes at various depths
;; in the IN-ADDR.ARPA domain, since Internet network numbers are either 1,
;; 2, or 3 octets. Network nodes are used to hold pointers to the primary
;; host names of gateways attached to that network. Since a gateway is, by
;; definition, on more than one network, it will typically have two or more
;; network nodes which point at it. Gateways will also have host level
;; pointers at their fully qualified addresses.
;; Both the gateway pointers at network nodes and the normal host pointers
;; at full address nodes use the PTR RR to point back to the primary domain
;; names of the corresponding hosts.
;; For example, the IN-ADDR.ARPA domain will contain information about the
;; ISI gateway between net 10 and 26, an MIT gateway from net 10 to MIT's
;; net 18, and hosts A.ISI.EDU and MULTICS.MIT.EDU. Assuming that ISI
;; gateway has addresses 10.2.0.22 and 26.0.0.103, and a name MILNET-
;; GW.ISI.EDU, and the MIT gateway has addresses 10.0.0.77 and 18.10.0.4
;; and a name GW.LCS.MIT.EDU, the domain database would contain:
;; 10.IN-ADDR.ARPA. PTR MILNET-GW.ISI.EDU.
;; 10.IN-ADDR.ARPA. PTR GW.LCS.MIT.EDU.
;; 18.IN-ADDR.ARPA. PTR GW.LCS.MIT.EDU.
;; 26.IN-ADDR.ARPA. PTR MILNET-GW.ISI.EDU.
;; 22.0.2.10.IN-ADDR.ARPA. PTR MILNET-GW.ISI.EDU.
;; 103.0.0.26.IN-ADDR.ARPA. PTR MILNET-GW.ISI.EDU.
;; 77.0.0.10.IN-ADDR.ARPA. PTR GW.LCS.MIT.EDU.
;; 4.0.10.18.IN-ADDR.ARPA. PTR GW.LCS.MIT.EDU.
;; 103.0.3.26.IN-ADDR.ARPA. PTR A.ISI.EDU.
;; 6.0.0.10.IN-ADDR.ARPA. PTR MULTICS.MIT.EDU.
;; Thus a program which wanted to locate gateways on net 10 would originate
;; a query of the form QTYPE=PTR, QCLASS=IN, QNAME=10.IN-ADDR.ARPA. It
;; would receive two RRs in response:
;; 10.IN-ADDR.ARPA. PTR MILNET-GW.ISI.EDU.
;; 10.IN-ADDR.ARPA. PTR GW.LCS.MIT.EDU.
;; The program could then originate QTYPE=A, QCLASS=IN queries for MILNET-
;; GW.ISI.EDU. and GW.LCS.MIT.EDU. to discover the Internet addresses of
;; these gateways.
;; A resolver which wanted to find the host name corresponding to Internet
;; host address 10.0.0.6 would pursue a query of the form QTYPE=PTR,
;; QCLASS=IN, QNAME=6.0.0.10.IN-ADDR.ARPA, and would receive:
;; 6.0.0.10.IN-ADDR.ARPA. PTR MULTICS.MIT.EDU.
;; Several cautions apply to the use of these services:
;; - Since the IN-ADDR.ARPA special domain and the normal domain
;; for a particular host or gateway will be in different zones,
;; the possibility exists that that the data may be inconsistent.
;; - Gateways will often have two names in separate domains, only
;; one of which can be primary.
;; - Systems that use the domain database to initialize their
;; routing tables must start with enough gateway information to
;; guarantee that they can access the appropriate name server.
;; - The gateway data only reflects the existence of a gateway in a
;; manner equivalent to the current HOSTS.TXT file. It doesn't
;; replace the dynamic availability information from GGP or EGP.
;; 3.6. Defining new types, classes, and special namespaces
;; The previously defined types and classes are the ones in use as of the
;; date of this memo. New definitions should be expected. This section
;; makes some recommendations to designers considering additions to the
;; existing facilities. The mailing list NAMEDROPPERS@SRI-NIC.ARPA is the
;; forum where general discussion of design issues takes place.
;; In general, a new type is appropriate when new information is to be
;; added to the database about an existing object, or we need new data
;; formats for some totally new object. Designers should attempt to define
;; types and their RDATA formats that are generally applicable to all
;; classes, and which avoid duplication of information. New classes are
;; appropriate when the DNS is to be used for a new protocol, etc which
;; requires new class-specific data formats, or when a copy of the existing
;; name space is desired, but a separate management domain is necessary.
;; New types and classes need mnemonics for master files; the format of the
;; master files requires that the mnemonics for type and class be disjoint.
;; TYPE and CLASS values must be a proper subset of QTYPEs and QCLASSes
;; respectively.
;; The present system uses multiple RRs to represent multiple values of a
;; type rather than storing multiple values in the RDATA section of a
;; single RR. This is less efficient for most applications, but does keep
;; RRs shorter. The multiple RRs assumption is incorporated in some
;; experimental work on dynamic update methods.
;; The present system attempts to minimize the duplication of data in the
;; database in order to insure consistency. Thus, in order to find the
;; address of the host for a mail exchange, you map the mail domain name to
;; a host name, then the host name to addresses, rather than a direct
;; mapping to host address. This approach is preferred because it avoids
;; the opportunity for inconsistency.
;; In defining a new type of data, multiple RR types should not be used to
;; create an ordering between entries or express different formats for
;; equivalent bindings, instead this information should be carried in the
;; body of the RR and a single type used. This policy avoids problems with
;; caching multiple types and defining QTYPEs to match multiple types.
;; For example, the original form of mail exchange binding used two RR
;; types one to represent a "closer" exchange (MD) and one to represent a
;; "less close" exchange (MF). The difficulty is that the presence of one
;; RR type in a cache doesn't convey any information about the other
;; because the query which acquired the cached information might have used
;; a QTYPE of MF, MD, or MAILA (which matched both). The redesigned
;; service used a single type (MX) with a "preference" value in the RDATA
;; section which can order different RRs. However, if any MX RRs are found
;; in the cache, then all should be there.
;; 4. MESSAGES
;; 4.1. Format
;; All communications inside of the domain protocol are carried in a single
;; format called a message. The top level format of message is divided
;; into 5 sections (some of which are empty in certain cases) shown below:
;; The names of the sections after the header are derived from their use in
;; standard queries. The question section contains fields that describe a
;; question to a name server. These fields are a query type (QTYPE), a
;; query class (QCLASS), and a query domain name (QNAME). The last three
;; sections have the same format: a possibly empty list of concatenated
;; resource records (RRs). The answer section contains RRs that answer the
;; question; the authority section contains RRs that point toward an
;; authoritative name server; the additional records section contains RRs
;; which relate to the query, but are not strictly answers for the
;; question.
;; The header section is always present. The header includes fields that
;; specify which of the remaining sections are present, and also specify
;; whether the message is a query or a response, a standard query or some
;; other opcode, etc.
;; 4.1.1. Header section format
(defbinary dns-header (:byte-order :big-endian)
;; A 16 bit identifier assigned by the program that
;; generates any kind of query. This identifier is copied
@ -488,7 +153,7 @@
;; 1 an inverse query (IQUERY)
;; 2 a server status request (STATUS)
;; 3-15 reserved for future use
(opcode 0 :type 4) ; TODO(tazjin): use define-enum
(opcode 0 :type 4)
;; Authoritative Answer - this bit is valid in responses,
;; and specifies that the responding name server is an
@ -617,8 +282,6 @@
;; Advancing the stream like this also ensures that the next
;; iteration occurs on a new fragment or the final terminating
;; byte.
;;
;; TODO(tazjin): Use lisp-binary:read-counted-string.
(dotimes (_ byte (collect (babel:octets-to-string fragment)
into fragments result-type vector))
(vector-push (read-byte stream) fragment))
@ -642,25 +305,6 @@
;; Always finish off the serialisation with a null-byte!
(write-byte 0 stream))
;; 4.1.2. Question section format
(defbinary dns-question (:byte-order :big-endian :export t)
;; a domain name represented
(qname "" :type (custom :lisp-type qname
:reader #'read-qname
:writer #'write-qname))
;; a two octet code which specifies the type of the query.
;; The values for this field include all codes valid for a
;; TYPE field, together with some more general codes which
;; can match more than one type of RR.
(qtype 0 :type 16) ;; TODO(tazjin): define type after the RR binary
;; a two octet code that specifies the class of the query. For
;; example, the QCLASS field is IN for the Internet.
(qclass 0 :type 16)) ; TODO(tazjin): enum?
;; 4.1.3. Resource record format
(define-enum dns-type 2
(:byte-order :big-endian)
@ -674,42 +318,76 @@
(TXT 16)
(SRV 33)
(AAAA 28)
(ANY 255)) ;; (typically wants SOA, MX, NS and MX)
;; ANY typically wants SOA, MX, NS and MX
(ANY 255))
(defbinary dns-question (:byte-order :big-endian :export t)
;; a domain name represented
(qname "" :type (custom :lisp-type qname
:reader #'read-qname
:writer #'write-qname))
;; a two octet code which specifies the type of the query.
(qtype 0 :type dns-type)
;; a two octet code that specifies the class of the query. For
;; example, the QCLASS field is IN for the Internet.
(qclass 0 :type 16))
(defbinary dns-rr (:byte-order :big-endian :export t)
(name nil :type (custom :lisp-type qname
:reader #'read-qname
:writer #'write-qname))
;; two octets containing one of the RR type codes. This
;; field specifies the meaning of the data in the RDATA
;; field.
;; two octets containing one of the RR type codes. This field
;; specifies the meaning of the data in the RDATA field.
(type 0 :type dns-type)
;; two octets which specify the class of the data in the
;; RDATA field.
(class 0 :type 16) ; TODO(tazjin): enum
;; two octets which specify the class of the data in the RDATA
;; field.
(class 0 :type 16)
;; a 32 bit unsigned integer that specifies the time
;; interval (in seconds) that the resource record may be
;; cached before it should be discarded. Zero values are
;; interpreted to mean that the RR can only be used for the
;; transaction in progress, and should not be cached.
;; a 32 bit unsigned integer that specifies the time interval (in
;; seconds) that the resource record may be cached before it should
;; be discarded. Zero values are interpreted to mean that the RR
;; can only be used for the transaction in progress, and should not
;; be cached.
(ttl 0 :type 32)
;; an unsigned 16 bit integer that specifies the length in
;; octets of the RDATA field.
;; an unsigned 16 bit integer that specifies the length in octets
;; of the RDATA field.
(rdlength 0 :type 16)
;; a variable length string of octets that describes the
;; resource. The format of this information varies
;; according to the TYPE and CLASS of the resource record.
;; For example, the if the TYPE is A and the CLASS is IN,
;; the RDATA field is a 4 octet ARPA Internet address.
;; a variable length string of octets that describes the resource.
;; The format of this information varies according to the TYPE and
;; CLASS of the resource record. For example, the if the TYPE is A
;; and the CLASS is IN, the RDATA field is a 4 octet ARPA Internet
;; address.
(rdata #() :type (eval (case type
;; TODO(tazjin): Deal with multiple strings in single RRDATA
((TXT) '(counted-string 1))
;; A 32-bit internet address in its
;; canonical representation of 4 integers.
((A) '(simple-array (unsigned-byte 8) (4)))
;; TODO(tazjin): Deal with multiple strings in single RRDATA
;; One or more <character-string>s.
((TXT) '(counted-string 1))
;; A <domain-name> which specifies the
;; canonical or primary name for the
;; owner. The owner name is an alias.
((CNAME) '(custom
:lisp-type qname
:reader #'read-qname
:writer #'write-qname))
;; A <domain-name> which specifies a host
;; which should be authoritative for the
;; specified class and domain.
((NS) '(custom
:lisp-type qname
:reader #'read-qname
:writer #'write-qname))
(otherwise `(simple-array (unsigned-byte 8) (,rdlength)))))))
(defbinary dns-message (:byte-order :big-endian :export t)