netlink/route/addr.scm \

@item @code{ipv4}

An IPv4 address.  Its value is a string that represents that address,

for instnace @code{"192.0.2.152"}

@item @code{ipv6}

An IPv6 address.  Its value is a string that represents that address,

for instnace @code{"2001:db8::0123:4567:89ab:cdef"}

@node Address Messages

@subsection Address Messages

The @code{(netlink route addr)} package defines the following data type:

@deffn {Datatype} addr-message

This datatype represents an address message with its routing attributes.  This

type of message is expected when using the @var{RTM_*ADDR} message types.

@table @asis

@item @code{family}

The network family, either @code{AF_INET} for IPv4 addresses, or @code{AF_INET6}

for IPv6 addresses.

@item @code{prefix-len}

The prefix length, i.e.@: the length of the prefix mask, in bits, if defined

for the address family.

@item @code{flags}

Address flags.  This can be a flag word of @code{IFA_F_SECONDARY} for secondary

address (old alias interface), @code{IFA_F_PERMANENT} for a permanent

address set by the user and other undocumented flags.

@item @code{scope}

The address scope.

@item @code{index}

The index of the device this address is for.

@item @code{attrs}

A list of attributes.  This field must contain a list of @code{nl-data}

structures, not a structure by itself.

@end table

@end deffn

  RTM_SETLINK

  (RTM_NEWADDR 20)

  RTM_DELADDR

  RTM_GETADDR)

  #:use-module ((netlink route addr) #:prefix route:)

      (,RTM_SETLINK . ,route:deserialize-link-message)

      (,RTM_NEWADDR . ,route:deserialize-addr-message)

      (,RTM_DELADDR . ,route:deserialize-addr-message)

      (,RTM_GETADDR . ,route:deserialize-addr-message))

               ,@route:%default-route-link-attr-decoder)

    (ipv4-attr ,(route:deserialize-route-attr 'ipv4-attr)

               ,@route:%default-route-ipv4-attr-decoder)

    (ipv6-attr ,(route:deserialize-route-attr 'ipv6-attr)

               ,@route:%default-route-ipv6-attr-decoder)))

;;;; 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)))))))))

           make-ipv4-route-attr

           make-ipv6-route-attr

           deserialize-route-attr-data-ipv4

           deserialize-route-attr-data-ipv6

           %default-route-link-attr-decoder

           %default-route-ipv4-attr-decoder

           %default-route-ipv6-attr-decoder))

(define (ipv4->bv addr)

  (u8-list->bytevector (map (lambda (n) (string->number n))

                            (string-split addr #\.))))

(define (make-ipv4-route-attr addr)

  (make-nl-data

    addr

    (lambda (addr) (bytevector-length (ipv4->bv addr)))

    (lambda (data pos bv)

      (let ((a (ipv4->bv data)))

        (bytevector-copy! a 0 bv pos (bytevector-length a))))))

;16 bytes

(define (ipv6->bv addr)

  (let loop ((num (inet-pton AF_INET6 addr)) (lst '()))

    (match lst

      ((_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _)

       (u8-list->bytevector (reverse lst)))

      (_

       (loop (quotient num 256) (cons (modulo num 256) lst))))))

(define (make-ipv6-route-attr addr)

  (make-nl-data

    addr

    (lambda (addr) (bytevector-length (ipv6->bv addr)))

    (lambda (data pos bv)

      (let ((a (ipv6->bv data)))

        (bytevector-copy! a 0 bv pos (bytevector-length a))))))

  (make-string-route-attr

    (or (false-if-exception (utf8->string bv))

        (make-string (bytevector-length bv) #\a))))

(define (deserialize-route-attr-data-ipv4 decoder bv pos)

  (make-ipv4-route-attr

    (string-join (map (lambda (n) (number->string n))

                      (bytevector->u8-list bv))

                 ".")))

(define (deserialize-route-attr-data-ipv6 decoder bv pos)

  (define (ipv6->number addr)

    (let loop ((addr (bytevector->u8-list addr)) (num 0))

      (match addr

        (() num)

        ((byte addr ...)

         (loop addr (+ (* 256 num) byte))))))

  (make-ipv6-route-attr

    (inet-ntop AF_INET6 (ipv6->number bv))))

(define %default-route-link-attr-decoder

  (default-route-attr-decoder deserialize-route-attr-data-ethernet))

(define %default-route-ipv4-attr-decoder

  (default-route-attr-decoder deserialize-route-attr-data-ipv4))

(define %default-route-ipv6-attr-decoder

  (default-route-attr-decoder deserialize-route-attr-data-ipv6))