;;;; Copyright (C) 2020 Julien Lepiller <julien@lepiller.eu>

;;;; 

;;;; This library is free software; you can redistribute it and/or

;;;; modify it under the terms of the GNU Lesser General Public

;;;; License as published by the Free Software Foundation; either

;;;; version 3 of the License, or (at your option) any later version.

;;;; 

;;;; This library is distributed in the hope that it will be useful,

;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of

;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

;;;; Lesser General Public License for more details.

;;;; 

;;;; You should have received a copy of the GNU Lesser General Public

;;;; License along with this library; if not, write to the Free Software

;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

;;;; 

(define-module (netlink route addr)

  #:use-module (ice-9 match)

  #:use-module (netlink data)

  #:use-module (netlink route attrs)

  #:use-module (srfi srfi-9)

  #:use-module (rnrs bytevectors)

  #:export (make-addr-message

            addr-message?

            addr-message-family

            addr-message-prefix-len

            addr-message-flags

            addr-message-scope

            addr-message-index

            addr-message-attrs

            deserialize-addr-message))

(define (align pos to)

  (+ pos -1 (- to (modulo (- pos 1) to))))

(define-data-type addr-message

  (lambda (msg)

    (+ 8 (apply + (map (lambda (d) (align (data-size d) 4)) attrs))))

  (lambda (msg pos bv)

    (match msg

      (($ addr-message-type family prefix-len flags scope index attrs)

       (bytevector-u8-set! bv pos family)

       (bytevector-u8-set! bv (+ pos 1) prefix-len)

       (bytevector-u8-set! bv (+ pos 2) flags)

       (bytevector-u8-set! bv (+ pos 3) scope)

       (bytevector-u32-set! bv (+ pos 4) index (native-endianness))

       (let loop ((attrs attrs) (pos (+ pos 8)))

         (match attrs

           ((attr attrs ...)

            (serialize attr pos bv)

            (loop attrs (+ pos (align (data-size attr) 4))))

           (() #t))))))

  (family addr-message-family addr-message-type-family)

  (prefix-len addr-message-prefix-len addr-message-type-prefix-len)

  (flags addr-message-flags addr-message-type-flags)

  (scope addr-message-scope addr-message-type-scope)

  (index addr-message-index addr-message-type-index)

  (attrs addr-message-attrs addr-message-type-attrs))

(define (deserialize-addr-message decoder bv pos)

  (let ((family (bytevector-u8-ref bv pos)))

    (make-addr-message

      family

      (bytevector-u8-ref bv (+ pos 1))

      (bytevector-u8-ref bv (+ pos 2))

      (bytevector-u8-ref bv (+ pos 3))

      (bytevector-u32-ref bv (+ pos 4) (native-endianness))

      (let ((len (bytevector-length bv)))

        (let loop ((pos (+ pos 8)) (attrs '()))

          (if (>= pos len)

              attrs

              (let ((attr (deserialize (cond

                                         ((equal? family AF_INET) 'ipv4-attr)

                                         ((equal? family AF_INET6) 'ipv6-attr)

                                         (else (throw 'unknown-family family)))

                                       decoder bv pos)))

                (loop (+ pos (align (data-size attr) 4))

                      (cons attr attrs)))))))))