1 ;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; Indent-tabs-mode: NIL -*-
3 ;;; lookup.lisp --- High-level name lookup.
5 ;;; Copyright (C) 2006-2007, Stelian Ionescu <sionescu@common-lisp.net>
6 ;;; Copyright (C) 2006-2007, Luis Oliveira <loliveira@common-lisp.net>
8 ;;; This code is free software; you can redistribute it and/or
9 ;;; modify it under the terms of the version 2.1 of
10 ;;; the GNU Lesser General Public License as published by
11 ;;; the Free Software Foundation, as clarified by the
12 ;;; preamble found here:
13 ;;; http://opensource.franz.com/preamble.html
15 ;;; This program is distributed in the hope that it will be useful,
16 ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
17 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 ;;; GNU General Public License for more details.
20 ;;; You should have received a copy of the GNU Lesser General
21 ;;; Public License along with this library; if not, write to the
22 ;;; Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
23 ;;; Boston, MA 02110-1301, USA
25 (in-package :net.sockets
)
27 (define-constant +max-ipv4-value
+ (1- (expt 2 32))
28 :documentation
"Integer denoting 255.255.255.255")
30 ;;;; High-level Interface
34 (defun remove-trailing-dot (string)
35 (assert (> (length string
) 1))
36 (assert (char= #\.
(char string
(1- (length string
)))))
37 (subseq string
0 (1- (length string
))))
39 (defun reply-error-condition (reply query-type
)
40 (cond ((dns-flag-p reply
:name-error
) 'resolver-no-name-error
)
41 ((dns-flag-p reply
:server-failure
) 'resolver-fail-error
)
42 ((loop :for rr
:across
(dns-message-answer reply
)
43 :never
(eq query-type
(dns-record-type rr
)))
44 'resolver-no-name-error
)))
46 (defun check-reply-for-errors (reply host query-type
)
47 (let ((condition (reply-error-condition reply query-type
)))
48 (and condition
(error condition
:data host
))))
50 (defun dns-lookup-host-by-address (address)
51 (let ((reply (dns-query address
:type
:ptr
)))
52 (check-reply-for-errors reply address
:ptr
)
53 (let ((hostname (remove-trailing-dot
54 (dns-rr-data (aref (dns-message-answer reply
) 0)))))
55 (assert (eq :ptr
(dns-record-type (aref (dns-message-answer reply
) 0))))
56 (values (list address
)
58 (list (cons hostname address
))))))
60 (defun lookup-host-by-address (address ipv6
)
61 (cond ((and (eq ipv6
:ipv6
)
62 (ipv4-address-p address
))
63 (setf address
(map-ipv4-address-to-ipv6 address
)))
65 (ipv6-ipv4-mapped-p address
))
66 (setf address
(map-ipv6-address-to-ipv4 address
))))
67 (multiple-value-bind (addresses truename aliases
)
68 (search-host-by-address address
)
69 (cond (addresses (values addresses truename aliases
))
70 (t (dns-lookup-host-by-address address
)))))
72 (defun process-one-reply (reply query-type
)
73 (let ((truename (dns-record-name (aref (dns-message-question reply
) 0)))
75 (loop :for rr
:across
(dns-message-answer reply
) :do
76 (switch ((dns-record-type rr
) :test
#'eq
)
77 (:cname
(setf truename
(dns-rr-data rr
)))
78 (query-type (let ((address (ensure-address (dns-rr-data rr
)))
79 (name (remove-trailing-dot (dns-record-name rr
))))
80 (push address addresses
)
81 (push (cons name address
) aliases
)))
82 (t (warn "Invalid RR type: ~S" (dns-record-type rr
)))))
83 (values (nreverse addresses
)
84 (remove-trailing-dot truename
)
87 (defun dns-lookup-host-in-one-domain (host query-type
)
88 (let ((reply (dns-query host
:type query-type
)))
89 (check-reply-for-errors reply host query-type
)
90 (process-one-reply reply query-type
)))
92 (defun merge-a-and-aaaa-replies (4-reply 6-reply
)
93 (multiple-value-bind (4-addresses 4-truename
4-aliases
)
94 (process-one-reply 4-reply
:a
)
95 (multiple-value-bind (6-addresses 6-truename
6-aliases
)
96 (process-one-reply 6-reply
:aaaa
)
97 (declare (ignore 6-truename
))
98 (values (nconc 4-addresses
6-addresses
)
100 (nconc 4-aliases
6-aliases
)))))
102 (defun dns-lookup-host-in-a-and-aaaa (host)
103 (let* ((4-reply (dns-query host
:type
:a
))
104 (4-err (reply-error-condition 4-reply
:a
))
105 (6-reply (dns-query host
:type
:aaaa
))
106 (6-err (reply-error-condition 6-reply
:aaaa
)))
109 (error (if (member 'resolver-fail-error
(list 4-err
6-err
)
112 'resolver-no-name-error
)
114 (4-err (process-one-reply 6-reply
:aaaa
))
115 (6-err (process-one-reply 4-reply
:a
))
116 (t (merge-a-and-aaaa-replies 4-reply
6-reply
)))))
118 (defun dns-lookup-host-by-name (host ipv6
)
120 ((nil) (dns-lookup-host-in-one-domain host
:a
))
121 ((:ipv6
) (dns-lookup-host-in-one-domain host
:aaaa
))
122 ((t) (dns-lookup-host-in-a-and-aaaa host
))))
124 (defun lookup-host-by-name (host ipv6
)
125 (multiple-value-bind (addresses truename aliases
)
126 (search-host-by-name host ipv6
)
127 (cond (addresses (values addresses truename aliases
))
128 (t (dns-lookup-host-by-name host ipv6
)))))
130 ;; TODO: * implement address selection as per RFC 3484
132 ;; * profile the whole thing
133 (defun lookup-host (host &key
(ipv6 *ipv6
*))
134 "Looks up a host by name or address. IPV6 determines the IPv6
135 behaviour, defaults to *IPV6*."
136 (check-type ipv6
(member nil
:ipv6 t
) "valid IPv6 configuration")
137 (let ((address (if (stringp host
)
138 (ignore-parse-errors (ensure-address host
))
139 (ensure-address host
))))
140 (update-monitor *resolv.conf-monitor
*)
141 (update-monitor *hosts-monitor
*)
143 (lookup-host-by-address address ipv6
))
145 (check-type host string
)
146 (lookup-host-by-name host ipv6
)))))