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Diffstat (limited to 'lisp/dns/client.lisp')
-rw-r--r-- | lisp/dns/client.lisp | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/lisp/dns/client.lisp b/lisp/dns/client.lisp new file mode 100644 index 000000000000..2dbe9ff31dcf --- /dev/null +++ b/lisp/dns/client.lisp @@ -0,0 +1,73 @@ +;; Implementation of a DoH-client, see RFC 8484 (DNS Queries over +;; HTTPS (DoH)) + +(in-package #:dns) + +;; The DoH client is configured with a URI Template [RFC6570] +(defvar *doh-base-url* "https://dns.google/resolve" + "Base URL of the service providing DNS-over-HTTP(S). Defaults to the + Google-hosted API.") + +(define-condition doh-error (error) + ((query-name :initarg :query-name + :reader doh-error-query-name + :type string) + (query-type :initarg :query-type + :reader doh-error-query-type + :type string) + (doh-url :initarg :doh-url + :reader doh-error-doh-url + :type string) + (status-code :initarg :status-code + :reader doh-error-status-code + :type integer) + (response-body :initarg :response-body + :reader doh-error-response-body + :type (or nil (vector (unsigned-byte 8)) string))) + + (:report (lambda (condition stream) + (let ((url (doh-error-doh-url condition)) + (status (doh-error-status-code condition)) + (body (doh-error-response-body condition))) + (format stream "DoH service at '~A' responded with non-success (~A): ~%~%~A" + url status body))))) + +(defun lookup-generic (name type &key (doh-url *doh-base-url*)) + (multiple-value-bind (body status) + (drakma:http-request doh-url + :decode-content t + ;; TODO(tazjin): Figure out why 'want-stream' doesn't work + :parameters `(("type" . ,type) + ("name" . ,name) + ("ct" . "application/dns-message"))) + (if (= 200 status) + (read-binary 'dns-message (flexi-streams:make-in-memory-input-stream body)) + + (restart-case (error 'doh-error + :query-name name + :query-type type + :doh-url doh-url + :status-code status + :response-body body) + (call-with-other-name (new-name) + :interactive (lambda () (list (the string (read)))) + :test (lambda (c) (typep c 'doh-error)) + (lookup-generic new-name type :doh-url doh-url)) + + (call-with-other-type (new-type) + :interactive (lambda () (list (the string (read)))) + :test (lambda (c) (typep c 'doh-error)) + (lookup-generic name new-type :doh-url doh-url)) + + (call-with-other-url (new-url) + :interactive (lambda () (list (the string (read)))) + :test (lambda (c) (typep c 'doh-error)) + (lookup-generic name type :doh-url new-url)))))) + +(defun lookup-txt (name) + "Look up the TXT records at NAME." + (lookup-generic name "TXT")) + +(defun lookup-mx (name) + "Look up the MX records at NAME." + (lookup-generic name "MX")) |