#|
Copyright (c) 2006 Risto Laakso
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products
   derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|#
(in-package :nio)

(declaim (optimize (debug 3) (speed 3) (space 0)))

;;;; FFI

(defconstant +af-inet+ 2)
(defconstant +af-inet6+ 30)

(defconstant +sock-stream+ 1)
(defconstant +sock-dgram+ 2)

(defcstruct sockaddr-in
  (len :uint8)
  (family :uint8)
  (port :uint16)
  (addr :uint32)
  (zero :char :count 8))

(defconstant +sockaddr-in-len+ #.(+ 1 1 2 4 8))

(defcstruct sockaddr-in6
  (len :uint8)
  (family :uint8)
  (port :uint16)
  (flowinfo :uint32)
  (addr :uint16 :count 8)
  (scope-id :uint32))

(defconstant +sockaddr-in6-len+ #.(+ 1 1 2 4 16 4))

(defcfun ("socket" %socket) :int
  (domain :int)
  (type :int)
  (protocol :int))

(defcfun ("inet_pton" %inet-pton) :int
  (af :int)
  (src :string)
  (dst :pointer))

(defcfun ("htons" %htons) :uint16
  (host-value :uint16))

(defcfun ("bind" %bind) :int
  (socket :int)
  (sockaddr :pointer)
  (socklent :long))

(defcfun ("listen" %listen) :int
  (socket :int)
  (backlog :int))

(defcfun ("accept" %accept) :int
  (socket :int)
  (sockaddr :pointer)
  (socklen :pointer))


(defun start-listen (socket-fd &optional (backlog 7))
  (%listen socket-fd backlog))


;;;; IPv4

(defun make-inet-socket (&optional (type :tcp))
  (%socket +af-inet+ (ecase type (:tcp +sock-stream+) (:udp +sock-dgram+)) 0))

(defun bind-inet-socket (socket-fd port &optional (addr "127.0.0.1"))
  (with-foreign-object (sa 'sockaddr-in)

    (memzero sa +sockaddr-in-len+)

    ;; init struct
    (setf (foreign-slot-value sa 'sockaddr-in 'len) +sockaddr-in-len+
	  (foreign-slot-value sa 'sockaddr-in 'port) (%htons port)
	  (foreign-slot-value sa 'sockaddr-in 'family) +af-inet+)

    ;; set addr
    (if (/= (%inet-pton +af-inet+ addr (foreign-slot-pointer sa 'sockaddr-in 'addr)) 1)
	(error "inet_pton: Bad address ~A!" addr))

    ;; bind
    (if (= (%bind socket-fd sa +sockaddr-in-len+) 0)
	t
	nil)))


;;;; IPv6

(defun make-inet6-socket (&optional (type :tcp))
  (%socket +af-inet6+ (ecase type (:tcp +sock-stream+) (:udp +sock-dgram+)) 0))

(defun bind-inet6-socket (socket-fd port &optional (addr "::1"))
  (with-foreign-object (sa 'sockaddr-in6)

    (memzero sa +sockaddr-in6-len+)

    ;; init struct
    (setf (foreign-slot-value sa 'sockaddr-in6 'len) +sockaddr-in6-len+
	  (foreign-slot-value sa 'sockaddr-in6 'port) (%htons port)
	  (foreign-slot-value sa 'sockaddr-in6 'family) +af-inet6+)

    ;; set addr
    (if (/= (%inet-pton +af-inet6+ addr (foreign-slot-pointer sa 'sockaddr-in6 'addr)) 1)
	(error "inet_pton: Bad address ~A!" addr))

    ;; bind
    (if (= (%bind socket-fd sa +sockaddr-in6-len+) 0)
	t
	nil)))



;;;; SOCKET I/O

(defclass async-socket-fd (async-fd)
  ((family :initform :unknown :initarg :family)
   (remote-host :initform nil :initarg :remote-host)
   (remote-port :initform nil :initarg :remote-port)))


(defun socket-accept (socket-fd)
  "Accept connection from SOCKET-FD. Allocates and returns socket structure denoting the connection."

  (flet ((parse-inet6-addr (addr) 
	   (let ((client-addr (foreign-slot-value addr 'sockaddr-in6 'addr)))
	     (loop for i from 0 to 7 
		for hex = (mem-aref client-addr :unsigned-short i)
		collect hex into res
		finally (return res))))

	 (parse-inet4-addr (addr)
	   (let ((client-addr (foreign-slot-value addr 'sockaddr-in 'addr)))
	     (loop for i from 0 to 3
		for hex = (logand (ash client-addr (- (* i 8))) #xFF)
		collect hex into res
		finally (return (nreverse res))))))

    (with-foreign-object (addr 'sockaddr-in6)

      (let ((len (foreign-alloc :unsigned-long :initial-element +sockaddr-in6-len+)))

	;; accept connection
      (let* ((res (%accept socket-fd addr len)) 
	     (async-socket-fd (make-instance 'async-socket-fd :read-fd res :write-fd res)))

	(unless (< res 0)
	  (let ((len-value (mem-ref len :unsigned-int)))

	    ;; parse sockaddr struct for remote client info

	    (with-slots (family remote-host remote-port) async-socket-fd
	      
	      (cond
		((= len-value +sockaddr-in6-len+)
		 (setf family :inet6
		       remote-port (foreign-slot-value addr 'sockaddr-in6 'port)
		       remote-host (parse-inet6-addr addr)))

		((= len-value +sockaddr-in-len+)
		 (setf family :inet4
		       remote-port (foreign-slot-value addr 'sockaddr-in 'port)
		       remote-host (parse-inet4-addr addr)))))


	    (foreign-free len)
	    (if (>= res 0) async-socket-fd nil)
	    )))))))


(defun remote-info (async-socket-fd)
  "Return FAMILY, REMOTE-HOST and REMOTE-PORT in list."
  (with-slots (family remote-host remote-port) async-socket-fd
    (list family remote-host remote-port)))