From 6a26c716f6f159e76dda56fd64bf346b569bb693 Mon Sep 17 00:00:00 2001 From: Mark Wooding Date: Sat, 13 Jul 2013 16:34:40 +0100 Subject: [PATCH] net.lisp: Write a bunch of better docstrings. --- net.lisp | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 80 insertions(+), 9 deletions(-) diff --git a/net.lisp b/net.lisp index 85faede..e1adf62 100644 --- a/net.lisp +++ b/net.lisp @@ -140,26 +140,46 @@ "Base class for IP addresses.")) (export 'ipaddr-family) -(defgeneric ipaddr-family (addr)) +(defgeneric ipaddr-family (addr) + (:documentation "Return the address family of ADDR, as a keyword.")) (export 'family-addrclass) (defgeneric family-addrclass (family) + (:documentation "Convert the keyword FAMILY into an `ipaddr' subclass.") (:method ((af symbol)) nil)) (export 'ipaddr-width) (defgeneric ipaddr-width (class) + (:documentation "Return the width, in bits, of addresses from CLASS. + + Alternatively, the CLASS may be given as an example object.") (:method ((object t)) (ipaddr-width (extract-class-name object)))) (export 'ipaddr-comparable-p) (defgeneric ipaddr-comparable-p (addr-a addr-b) + (:documentation "Is it meaningful to compare ADDR-A and ADDR-B?") (:method ((addr-a ipaddr) (addr-b ipaddr)) (eq (class-of addr-a) (class-of addr-b)))) (defun guess-address-class (str &key (start 0) (end nil)) + "Return a class name for the address in (the given substring of) STR. + + This ought to be an extension point for additional address families, but + it isn't at the moment." (cond ((position #\: str :start start :end end) 'ip6addr) (t 'ip4addr))) (defgeneric parse-partial-ipaddr (class str &key start end min max) + (:documentation + "Parse (a substring of) STR into a partial address of the given CLASS. + + Returns three values: the parsed address fragment, as an integer; and the + low and high bit positions covered by the response. + + The CLASS may instead be an example object of the required class. The MIN + and MAX arguments bound the number of bits acceptable in the response; the + result is shifted so that the most significant component of the returned + address is in the same component as bit position MAX.") (:method ((object t) str &rest keywords) (apply #'parse-partial-ipaddr (extract-class-name object) str keywords))) @@ -191,8 +211,7 @@ (export 'ipaddr-string) (defgeneric ipaddr-string (ip) - (:documentation - "Transform the address IP into a string in dotted-quad form.")) + (:documentation "Transform the address IP into a numeric textual form.")) (defmethod print-object ((addr ipaddr) stream) (print-unreadable-object (addr stream :type t) @@ -263,6 +282,7 @@ (export 'ipnet-family) (defgeneric ipnet-family (ipn) + (:documentation "Return the address family of IPN, as a keyword.") (:method ((ipn ipnet)) (ipaddr-family (ipnet-net ipn)))) (export 'ipnet-addr) @@ -276,8 +296,9 @@ (export 'make-ipnet) (defun make-ipnet (net mask) - "Construct an IP-network object given the NET and MASK; these are - transformed as though by `ipaddr' and `ipmask'." + "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 net mask))) (ipaddr-ipnet (mask-ipaddr net mask) mask))) @@ -316,7 +337,23 @@ (write-string (ipnet-string ipn) stream))) (defun parse-subnet (class width max str &key (start 0) (end nil) (slashp t)) - "Parse a subnet description from a (substring of) STR." + "Parse a subnet description from (a substring of) STR. + + Suppose we have a parent network, with a prefix length of MAX. The WIDTH + gives the overall length of addresses of the appropriate class, i.e., + (ipaddr-width WIDTH), but in fact callers have already computed this for + their own reasons. + + Parse (the designated substring of) STR to construct the base address of a + subnet. The string should have the form BASE/MASK, where the MASK is + either a literal bitmask (in the usual syntax for addresses) or an integer + prefix length. An explicit prefix length is expected to cover the entire + address including the parent prefix: an error is signalled if the prefix + isn't long enough to cover any of the subnet. A mask is parsed relative + to the end of the parent address, just as the subnet base address is. + + Returns the relative base address and mask as two integer values." + (setf-default end (length str)) (let ((sl (and slashp (position #\/ str :start start :end end)))) (multiple-value-bind (addr lo hi) @@ -360,7 +397,11 @@ (export 'string-ipnet) (defun string-ipnet (str &key (start 0) (end nil)) - "Parse an IP-network from the string STR." + "Parse an IP network description from the string STR. + + A network description has the form ADDRESS/MASK, where the ADDRESS is a + base address in numeric form, and the MASK is either a netmask in the same + form, or an integer prefix length." (setf str (stringify str)) (setf-default end (length str)) (let ((addr-class (guess-address-class str :start start :end end))) @@ -374,7 +415,13 @@ (defun parse-subipnet (ipn str &key (start 0) (end nil) (slashp t)) "Parse STR as a subnet of IPN. - This is mostly a convenience interface over `parse-subnet'." + This is mostly a convenience interface over `parse-subnet'; we compute + various of the parameters from IPN rather than requiring them to be passed + in explicitly. + + Returns two values: the combined base address, as an `ipnaddr' and + combined mask, as an integer." + (let* ((addr-class (extract-class-name (ipnet-net ipn))) (width (ipaddr-width addr-class)) (max (- width @@ -387,7 +434,21 @@ (export 'string-subipnet) (defun string-subipnet (ipn str &key (start 0) (end nil)) - "Parse an IP subnet from a parent net IPN and a suffix string STR." + "Parse an IP subnet from a parent net IPN and a suffix string STR. + + The (substring of) STR is expected to have the form ADDRESS/MASK, where + ADDRESS is a relative subnet base address, and MASK is either a relative + subnet mask or a (full) prefix length. Returns the resulting ipnet. If + the relative base address overlaps with the existing subnet (because the + base network's prefix length doesn't cover a whole number of components), + then the subnet base must either agree in the overlapping portion with the + parent base address or be zero. + + For example, if IPN is the network 172.29.0.0/16, then `199/24' or + `199/255' both designate the subnet 172.29.199.0/24. Similarly, starting + from 2001:ba8:1d9:8000::/52, then `8042/ffff' and `42/64' both designate + the network 2001:ba8:1d9:8042::/64." + (multiple-value-bind (addr mask) (parse-subipnet ipn str :start start :end end) (ipaddr-ipnet addr mask))) @@ -798,6 +859,16 @@ (export 'net-parse-to-ipnets) (defun net-parse-to-ipnets (form &optional (family t)) + "Parse FORM into a list of ipnet objects. + + The FORM can be any of the following. + + * NAME -- a named network, established using `net-create' or `defnet' + + * IPNET -- a network, in a form acceptable to `ipnet' + + * ((FAMILY . FORM) ...) -- a sequence of networks, filtered by FAMILY" + (flet ((hack (form family) (let* ((form (if (and (consp form) (endp (cdr form))) -- 2.11.0