backplane-dns/backplane-dns.lisp

214 lines
7.3 KiB
Common Lisp

;;;; backplane-dns.lisp
(in-package #:backplane-dns)
(defun xmpp-connect (hostname username password)
(let ((conn (xmpp:connect-tls :hostname hostname)))
(xmpp:auth conn username password "backplane")
conn))
(defun getenv-or-fail (env-var &optional default)
(let ((value (uiop:getenv env-var)))
(if (null value)
(if default
default
(uiop:die 1 "unable to find required env var: ~a" env-var))
value)))
(defclass dns-record ()
((id :col-type integer
:col-identity t
:reader id)
(domain-id :col-type integer
:col-name "domain_id"
:initarg :domain-id
:reader domain-id)
(name :col-type (varchar 255)
:initarg :name
:reader record-name)
(type :col-type (varchar 10)
:initarg :type
:reader record-type)
(content :col-type (varchar 65535)
:initarg :content
:accessor record-content))
(:metaclass postmodern:dao-class)
(:table-name "records")
(:keys id))
(defclass dns-domain ()
((id :col-type integer
:col-identity t
:reader id)
(name :col-type (varchar 255)
:initarg :name
:reader domain-name)
(master :col-type (or (varchar 128) db-null)
:initarg :master
:reader domain-master)
(type :col-type (varchar 6)
:initarg :type
:reader domain-type))
(:metaclass postmodern:dao-class)
(:table-name domains)
(:keys id))
(defclass request ()
((sender :initarg :sender)))
(defclass change-request-ipv4 (request)
((hostname :initarg :hostname)
(domain :initarg :domain)
(ip-address :initarg :ip-address)))
(defclass unknown-request (request)
((text :initarg :text
:reader text)))
(defclass result ()
((message :initarg :message)))
(defclass result/success (result) ())
(defclass result/error (result) ())
(defun make-success (&optional msg)
(make-instance 'result/success :message msg))
(defun make-error (&optional msg)
(make-instance 'result/error :message msg))
(defparameter *hostname-rx*
"([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9\-]*[A-Za-z0-9])")
(defun get-domain (name)
(car (select-dao 'dns-domain (:= 'name name))))
(define-condition domain-name-missing (error)
((missing-domain :initarg :domain :reader missing-domain)))
(defun host-a-record (hostname domain)
(if-let ((domain-id (some-> domain
(get-domain)
(id))))
(car (select-dao 'dns-record
(:= 'name hostname)
(:= 'domain-id domain-id)
(:= 'type "A")))
(error 'domain-name-missing :domain domain)))
(defun set-host-v4ip (host domain v4ip)
(let* ((full-hostname (format nil "~A.~A" host domain))
(a-record (host-a-record full-hostname domain)))
(if a-record
(progn (setf (record-content a-record) v4ip)
(update-dao a-record))
(if-let ((domain-id (some-> domain (get-domain) (id))))
(insert-dao (make-instance 'dns-record
:domain-id domain-id
:name full-hostname
:type "A"
:content v4ip))))))
(defun split-string (string &optional (char #\Space))
(split-sequence:split-sequence char string))
(let ((hostname-extractor-rx
(cl-ppcre:create-scanner
`(:SEQUENCE :START-ANCHOR "host-"
(:REGISTER (:REGEX ,*hostname-rx*))
#\@
(:REGEX ,*hostname-rx*) :END-ANCHOR))))
(defun sender-hostname (sender)
(cl-ppcre:register-groups-bind (hostname nil)
(hostname-extractor-rx sender)
hostname)))
(defgeneric render-result (result))
(defmethod render-result ((res result/success))
(with-slots (message) res
(if message
(format nil "OK: ~A" message)
"OK")))
(defmethod render-result ((res result/error))
(with-slots (message) res
(if message
(format nil "ERROR: ~A" message)
"ERROR")))
(defun parse-message (message)
(let ((from (xmpp:from message)))
(trivia:match (split-string (xmpp:body message))
((list "REQUEST-CHANGE-IPV4" domain ip)
(make-instance 'change-request-ipv4
:sender from
:hostname (sender-hostname from)
:domain domain
:ip-address ip))
(_ (make-instance 'unknown-request
:sender from
:text (xmpp:body message))))))
(defgeneric handle-message (message))
(defmethod handle-message ((message change-request-ipv4))
(with-slots (hostname domain ip-address) message
(handler-case
(progn (set-host-v4ip hostname domain ip-address)
(make-success (format nil "ipv4 for host ~a in domain ~a set to ~a"
hostname domain ip-address)))
(error (text)
(make-error (format nil "unknown error setting host v4ip: ~A"
text))))))
(defmethod handle-message ((message unknown-request))
(make-error (format nil "unknown message: ~A" (text message))))
(defmethod xmpp:handle ((conn xmpp:connection) (message xmpp:message))
(xmpp:message conn
(xmpp:from message)
(-> message
(parse-message)
(handle-message)
(render-result))))
(defun with-backplane (xmpp-host xmpp-username xmpp-password f)
(let ((backplane (xmpp:connect-tls :hostname xmpp-host)))
(xmpp:auth backplane
xmpp-username
xmpp-password
"server"
:mechanism :sasl-plain)
(funcall f backplane)))
(defun backplane-dns-listen (&key
xmpp-host
xmpp-username
xmpp-password
db-host
db-name
db-username
db-password)
(postmodern:with-connection (list db-name db-username db-password db-host :use-ssl :try)
(with-backplane xmpp-host xmpp-username xmpp-password
(lambda (backplane)
(xmpp:receive-stanza-loop backplane)))))
(defun read-file-line (filename)
(let ((input (open filename :if-does-not-exist nil)))
(read-line input)))
(defun start-listener-with-env ()
(backplane-dns-listen
:xmpp-host (getenv-or-fail "FUDO_DNS_BACKPLANE_XMPP_HOSTNAME")
:xmpp-username (getenv-or-fail "FUDO_DNS_BACKPLANE_XMPP_USERNAME")
:xmpp-password (read-file-line (getenv-or-fail "FUDO_DNS_BACKPLANE_XMPP_PASSWORD_FILE"))
:db-name (getenv-or-fail "FUDO_DNS_BACKPLANE_DATABASE_NAME")
:db-username (getenv-or-fail "FUDO_DNS_BACKPLANE_DATABASE_USERNAME")
:db-host (getenv-or-fail "FUDO_DNS_BACKPLANE_DATABASE_HOSTNAME")
:db-password (read-file-line (getenv-or-fail "FUDO_DNS_BACKPLANE_DATABASE_PASSWORD_FILE"))))