-(defun mask (n)
- "Return 2^N - 1: i.e., a mask of N set bits."
- (1- (ash 1 n)))
-(deftype u32 ()
- "The type of unsigned 32-bit values."
- '(unsigned-byte 32))
-(deftype ipaddr ()
- "The type of IP (version 4) addresses."
- 'u32)
-
-(defun string-ipaddr (str &key (start 0) (end nil))
- "Parse STR as an IP address in dotted-quad form and return the integer
-equivalent. STR may be anything at all: it's converted as if by
-`stringify'. The START and END arguments may be used to parse out a
-substring."
- (setf str (stringify str))
- (unless end
- (setf end (length str)))
- (let ((addr 0) (noct 0))
- (loop
- (let* ((pos (position #\. str :start start :end end))
- (i (parse-integer str :start start :end (or pos end))))
- (unless (<= 0 i 256)
- (error "IP address octet out of range"))
- (setf addr (+ (* addr 256) i))
- (incf noct)
- (unless pos
- (return))
- (setf start (1+ pos))))
- (unless (= noct 4)
- (error "Wrong number of octets in IP address"))
- addr))
-(defun ipaddr-byte (ip n)
- "Return byte N (from most significant downwards) of an IP address."
- (assert (<= 0 n 3))
- (logand #xff (ash ip (* -8 (- 3 n)))))
-(defun ipaddr-string (ip)
- "Transform the address IP into a string in dotted-quad form."
- (check-type ip ipaddr)
- (join-strings #\. (collecting ()
- (dotimes (i 4)
- (collect (ipaddr-byte ip i))))))
-(defun ipaddrp (ip)
- "Answer true if IP is a valid IP address in integer form."
- (typep ip 'ipaddr))
-(defun ipaddr (ip)
- "Convert IP to an IP address. If it's an integer, return it unchanged;
-otherwise convert by `string-ipaddr'."
- (typecase ip
- (ipaddr ip)
- (t (string-ipaddr ip))))
-
-(defun integer-netmask (i)
- "Given an integer I, return a netmask with its I top bits set."
- (- (ash 1 32) (ash 1 (- 32 i))))
-(defun ipmask (ip)
- "Transform IP into a netmask. If it's a small integer then it's converted
-by `integer-netmask'; if nil, then all-bits-set; otherwise convert using
-`ipaddr'."
- (typecase ip
- (null (mask 32))
- ((integer 0 32) (integer-netmask ip))
- (t (ipaddr ip))))
-(defun ipmask-cidl-slash (mask)
- "Given a netmask MASK, return an integer N such that (integer-netmask N) =
-MASK, or nil if this is impossible."
- (dotimes (i 33)
- (when (= mask (integer-netmask i))
- (return i))))
-
-(defun make-ipnet (net mask)
- "Construct an IP-network object given the NET and MASK; these are
-transformed as though by `ipaddr' and `ipmask'."
- (let ((net (ipaddr net))
- (mask (ipmask mask)))
- (cons (logand net mask) mask)))
-(defun string-ipnet (str &key (start 0) (end nil))
- "Parse an IP-network from the string STR."
- (setf str (stringify str))
- (unless end (setf end (length str)))
- (let ((sl (position #\/ str :start start :end end)))
- (if sl
- (make-ipnet (parse-ipaddr (subseq str start sl))
- (if (find #\. str :start (1+ sl) :end end)
- (string-ipaddr str :start (1+ sl) :end end)
- (integer-netmask (parse-integer str
- :start (1+ sl)
- :end end))))
- (make-ipnet (parse-ipaddr (subseq str start end))
- (integer-netmask 32)))))
-(defun ipnet (net &optional mask)
- "Construct an IP-network object from the given arguments. A number of
-forms are acceptable:
-
- * NET MASK -- as for `make-ipnet'.
- * ADDR -- a single address (equivalent to ADDR 32)
- * (NET . MASK|nil) -- a single-object representation.
- * IPNET -- return an equivalent (`equal', not necessarily `eql') version."
- (cond (mask (make-ipnet net mask))
- ((or (stringp net) (symbolp net)) (string-ipnet net))
- (t (apply #'make-ipnet (pairify net 32)))))
-(defun ipnet-net (ipn)
- "Return the base network address of IPN."
- (car ipn))
-(defun ipnet-mask (ipn)
- "Return the netmask of IPN."
- (cdr ipn))
-(defmacro with-ipnet ((net mask) ipn &body body)
- "Evaluate BODY with NET and MASK bound to the base address and netmask of
-IPN. Either NET or MASK (or, less usefully, both) may be nil if not wanted."
- (with-gensyms tmp
- `(let ((,tmp ,ipn))
- (let (,@(and net `((,net (ipnet-net ,tmp))))
- ,@(and mask `((,mask (ipnet-mask ,tmp)))))
- ,@body))))
-(defun ipnet-pretty (ipn)
- "Convert IPN to a pretty cons-cell form."
- (with-ipnet (net mask) ipn
- (cons (ipaddr-string net)
- (or (ipmask-cidl-slash mask) (ipaddr-string mask)))))
-(defun ipnet-string (ipn)
- "Convert IPN to a string."
- (with-ipnet (net mask) ipn
- (format nil "~A/~A"
- (ipaddr-string net)
- (or (ipmask-cidl-slash mask) (ipaddr-string mask)))))
-(defun ipnet-broadcast (ipn)
- "Return the broadcast address for the network IPN."
- (with-ipnet (net mask) ipn
- (logior net (logxor (mask 32) mask))))
-(defun ipnet-hosts (ipn)
- "Return the number of available addresses in network IPN."
- (ash 1 (- 32 (logcount (ipnet-mask ipn)))))
-(defun ipnet-host (ipn host)
- "Return the address of the given HOST in network IPN. This works even with
-a non-contiguous netmask."
- (check-type host u32)
- (with-ipnet (net mask) ipn
- (let ((i 0) (m 1) (a net) (h host))
- (loop
- (when (>= i 32)
- (error "Host index ~D out of range for network ~A"
- host (ipnet-pretty ipn)))
- (cond ((zerop h)
- (return a))
- ((logbitp i mask)
- (setf h (ash h 1)))
- (t
- (setf a (logior a (logand m h)))
- (setf h (logandc2 h m))))
- (setf m (ash m 1))
- (incf i)))))
-(defun ipaddr-networkp (ip ipn)
- "Returns true if address IP is within network IPN."
- (with-ipnet (net mask) ipn
- (= net (logand ip mask))))
-(defun ipnet-subnetp (ipn subn)
- "Returns true if SUBN is a (non-strict) subnet of IPN."
- (with-ipnet (net mask) ipn
- (with-ipnet (subnet submask) subn
- (and (= net (logand subnet mask))
- (= submask (logior mask submask))))))
-
-(defun resolve-hostname (name)
- "Resolve a hostname to an IP address using the DNS, or return nil."
- (let ((he (ext:lookup-host-entry name)))
- (and he
- (ext:host-entry-addr he))))
-(defun canonify-hostname (name)
- "Resolve a hostname to canonical form using the DNS, or return nil."
- (let ((he (ext:lookup-host-entry name)))
- (and he
- (ext:host-entry-name he))))
-(defun parse-ipaddr (addr)
- "Convert the string ADDR into an IP address: tries all sorts of things:
-
- (NET [INDEX]) -- index a network: NET is a network name defined by defnet;
- INDEX is an index or one of the special symbols understood by net-host,
- and defaults to :next
- INTEGER -- an integer IP address
- IPADDR -- an IP address in dotted-quad form
- HOST -- a host name defined by defhost
- DNSNAME -- a name string to look up in the DNS"
- (cond ((listp addr)
- (destructuring-bind
- (net host)
- (pairify addr :next)
- (net-host (or (net-find net)
- (error "Network ~A not found" net))
- host)))
- ((ipaddrp addr) addr)
- (t
- (setf addr (string-downcase (stringify addr)))
- (or (host-find addr)
- (and (plusp (length addr))
- (digit-char-p (char addr 0))
- (string-ipaddr addr))
- (resolve-hostname (stringify addr))
- (error "Host name ~A unresolvable" addr)))))
-
-(defvar *hosts* (make-hash-table :test #'equal)
- "The table of known hostnames.")
-(defun host-find (name)
- "Find a host by NAME."
- (gethash (string-downcase (stringify name)) *hosts*))
-(defun (setf host-find) (addr name)
- "Make NAME map to ADDR (must be an ipaddr in integer form)."
- (setf (gethash (string-downcase (stringify name)) *hosts*) addr))
-(defun host-create (name addr)
- "Make host NAME map to ADDR (anything acceptable to parse-ipaddr)."
- (setf (host-find name) (parse-ipaddr addr)))
-(defmacro defhost (name addr)
- "Main host definition macro. Neither NAME nor ADDR is evaluated."
- `(progn
- (host-create ',name ',addr)
- ',name))
-
-(defstruct (net (:predicate netp))
- "A network structure. Slots:
-
-NAME The network's name, as a string
-IPNET The network base address and mask
-HOSTS Number of hosts in the network
-NEXT Index of the next unassigned host"
- name
- ipnet
- hosts
- next)
-
-(defvar *networks* (make-hash-table :test #'equal)
- "The table of known networks.")
-(defun net-find (name)
- "Find a network by NAME."
- (gethash (string-downcase (stringify name)) *networks*))
-(defun (setf net-find) (net name)
- "Make NAME map to NET."
- (setf (gethash (string-downcase (stringify name)) *networks*) net))
-(defun net-get-as-ipnet (form)
- "Transform FORM into an ipnet. FORM may be a network name, or something
-acceptable to the ipnet function."
- (let ((net (net-find form)))
- (if net (net-ipnet net)
- (ipnet form))))
-(defun net-create (name &rest args)
- "Construct a new network called NAME and add it to the map. The ARGS
-describe the new network, in a form acceptable to the ipnet function."
- (let ((ipn (apply #'ipnet args)))
- (setf (net-find name)
- (make-net :name (string-downcase (stringify name))
- :ipnet ipn
- :hosts (ipnet-hosts ipn)
- :next 1))))
-(defmacro defnet (name &rest args)
- "Main network definition macro. Neither NAME nor any of the ARGS is
-evaluated."
- `(progn
- (net-create ',name ,@(mapcar (lambda (x) `',x) args))
- ',name))
-(defun net-next-host (net)
- "Given a NET, return the IP address (as integer) of the next available
-address in the network."
- (unless (< (net-next net) (net-hosts net))
- (error "No more hosts left in network ~A" (net-name net)))
- (let ((next (net-next net)))
- (incf (net-next net))
- (net-host net next)))
-(defun net-host (net host)
- "Return the given HOST on the NEXT. HOST may be an index (in range, of
-course), or one of the keywords:
-:NEXT next host, as by net-next-host
-:NET network base address
-:BROADCAST network broadcast address"
- (case host
- (:next (net-next-host net))
- (:net (ipnet-net (net-ipnet net)))
- (:broadcast (ipnet-broadcast (net-ipnet net)))
- (t (ipnet-host (net-ipnet net) host))))
~mdw / zone / blobdiff