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[dhcp] 08/08: fix bugs in serializer and deserializer
From: |
Rohan Prinja |
Subject: |
[dhcp] 08/08: fix bugs in serializer and deserializer |
Date: |
Mon, 15 Jun 2015 19:26:23 +0000 |
wenderen pushed a commit to branch master
in repository dhcp.
commit 0937fcf663579d0bc7cd31a8df371e01da2b31d5
Author: Rohan Prinja <address@hidden>
Date: Tue Jun 16 00:55:06 2015 +0530
fix bugs in serializer and deserializer
---
dhcp/messages.scm | 153 +++++++++++++++++++++++++++--------------------
tests/dhcp-messages.scm | 29 +++++++--
2 files changed, 112 insertions(+), 70 deletions(-)
diff --git a/dhcp/messages.scm b/dhcp/messages.scm
index ff7024b..4ed2266 100644
--- a/dhcp/messages.scm
+++ b/dhcp/messages.scm
@@ -27,9 +27,14 @@
#:use-module (rnrs enums)
#:export (<dhcp-msg>
make-dhcp-msg
+ make-dhcp-message ; wrapper for make-dhcp-msg
+
+ make-dhcpdiscover
dhcp-msg?
+ bytevector-slice
+
dhcp-msg-op set-dhcp-msg-op!
dhcp-msg-htype set-dhcp-msg-htype!
dhcp-msg-hlen set-dhcp-msg-hlen!
@@ -49,11 +54,19 @@
set-broadcast-bit
unset-broadcast-bit
option-value
- serialize-dhcp-message
- deserialize-dhcp-message
- message-type
- make-dhcpdiscover
- map-type-to-code))
+
+ serialize-dhcp-msg
+ deserialize-dhcp-msg
+ deserialize-options
+
+ msg-type
+
+ retrieve-secs
+ retrieve-xid
+ retrieve-ciaddr
+
+ map-type-to-code
+ map-type-to-op))
;; Magic cookie that starts off the 'options' field
;; in a DHCP message packet.
@@ -116,75 +129,77 @@
;; remaining bits are always zero, see Figure 2, RFC 2131.
(define-syntax-rule (set-broadcast-bit msg)
(set-dhcp-msg-flags #x8000))
+
(define-syntax-rule (unset-broadcast-bit msg)
(set-dhcp-msg-flags 0))
-#;(define (serialize-options! opts dst idx)
- "Copy the options field OPTS from a <dhcp-message> into a
+(define (serialize-options! opts dst idx)
+ "Copy the options field OPTS from a <dhcp-msg> into a
bytevector. OPTS is a vector, DST is a bytevector.
Copying starts at index IDX in DST. This function mutates DST.
-If an option is #f, it means it does not exist, so it is
+If an option is #f, it does not exist, so it is
simply ignored whilst serializing."
- (let loop ((i 0))
- (if (< i 256)
+ (let loop ((i 0) (to idx))
+ (if (< i 255)
(let* ((opt (vector-ref opts i)))
- (if (eq? #f opt)
- (loop (1+ i))
+ (if (eq? #f opt) ; option not present
+ (loop (1+ i) to)
(let ((code i)
(len (dhcp-option-len opt))
(val (dhcp-option-val opt)))
(begin
(if (zero? len)
- (bytevector-u8-set! dst idx code)
+ (bytevector-u8-set! dst to code)
(begin
- (bytevector-u8-set! dst idx code)
- (bytevector-u8-set! dst (1+ idx) len)
- (bytevector-copy! val 0 dst (+ idx 2) len)))
- (loop (1+ i)))))))))
+ (bytevector-u8-set! dst to code)
+ (bytevector-u8-set! dst (1+ to) len)
+ (bytevector-copy! val 0 dst (+ to 2) len)))
+ (loop (1+ i) (+ to 2 len))))))
+ (bytevector-u8-set! dst to 255))))
-; Serialize a <dhcp-message> object into a bytevector.
-#;(define-method (serialize-dhcp-message (msg <dhcp-message>))
+(define (serialize-dhcp-msg msg)
+ "Serialize a <dhcp-message> record MSG into a bytevector"
(let* ((res (make-bytevector 576 0))
- (chaddr (slot-ref msg 'chaddr))
+ (chaddr (dhcp-msg-chaddr msg))
(chaddr-len (bytevector-length chaddr))
(padded-chaddr (make-bytevector 16 0))
(_ (bytevector-copy! chaddr 0
padded-chaddr (- 16 chaddr-len)
chaddr-len)))
- (bytevector-u8-set! res 0 (slot-ref msg 'op))
- (bytevector-u8-set! res 1 (slot-ref msg 'htype))
- (bytevector-u8-set! res 2 (slot-ref msg 'hlen))
- (bytevector-u8-set! res 3 (slot-ref msg 'hops))
- (bytevector-u32-set! res 4 (slot-ref msg 'xid) (endianness big))
- (bytevector-u16-set! res 8 (slot-ref msg 'secs) (endianness big))
- (bytevector-u16-set! res 10 (slot-ref msg 'flags) (endianness big))
- (bytevector-copy! (slot-ref msg 'ciaddr) 0 res 12 4)
- (bytevector-copy! (slot-ref msg 'yiaddr) 0 res 16 4)
- (bytevector-copy! (slot-ref msg 'siaddr) 0 res 20 4)
- (bytevector-copy! (slot-ref msg 'giaddr) 0 res 24 4)
+ (bytevector-u8-set! res 0 (dhcp-msg-op msg))
+ (bytevector-u8-set! res 1 (dhcp-msg-htype msg))
+ (bytevector-u8-set! res 2 (dhcp-msg-hlen msg))
+ (bytevector-u8-set! res 3 (dhcp-msg-hops msg))
+ (bytevector-u32-set! res 4 (dhcp-msg-xid msg) (endianness big))
+ (bytevector-u16-set! res 8 (dhcp-msg-secs msg) (endianness big))
+ (bytevector-u16-set! res 10 (dhcp-msg-flags msg) (endianness big))
+ (bytevector-copy! (dhcp-msg-ciaddr msg) 0 res 12 4)
+ (bytevector-copy! (dhcp-msg-yiaddr msg) 0 res 16 4)
+ (bytevector-copy! (dhcp-msg-siaddr msg) 0 res 20 4)
+ (bytevector-copy! (dhcp-msg-giaddr msg) 0 res 24 4)
(bytevector-copy! padded-chaddr 0 res 28 16)
- (bytevector-copy! (slot-ref msg 'sname) 0 res 44 64)
- (bytevector-copy! (slot-ref msg 'file) 0 res 108 128)
+ (bytevector-copy! (dhcp-msg-sname msg) 0 res 44 64)
+ (bytevector-copy! (dhcp-msg-file msg) 0 res 108 128)
(bytevector-copy! *magic-cookie* 0 res 236 4)
- (serialize-options! (slot-ref msg 'options) res 240)
+ (serialize-options! (dhcp-msg-options msg) res 240)
res))
-; Read options from a bytevector 'src' starting at index
-; 'idx' and returns a vector of <dhcp-option> objects.
-#;(define (deserialize-options src idx)
+(define (deserialize-options src idx)
+ "Read options from a bytevector SRC starting at index
+IDX and returns a vector of <dhcp-option> records. We ignore
+the PAD option since its only purpose is to pad the
+bytevector; it carries no other useful information."
(define (helper src i res)
(if (= i (bytevector-length src))
res ; nothing more to read from 'src'
(let* ((code (bytevector-u8-ref src i)))
- (if (or (= code 0) (code 255))
- (begin
- (slot-set! res code (make-dhcp-option code 0 #f))
- (helper src (+ i 1) res))
+ (if (= code 255)
+ res ; we have seen an 'end' option, stop reading
(let* ((len (bytevector-u8-ref src (+ i 1)))
(val (make-bytevector len))
(_ (bytevector-copy! src (+ i 2) val 0 len)))
(begin
- (slot-set! res code (make-dhcp-option code len val))
+ (vector-set! res code (make-dhcp-option code len val))
(helper src (+ i 2 len) res)))))))
(helper src idx (make-vector 256 #f)))
@@ -199,20 +214,24 @@ from BV starting at index START"
(bytevector-copy! bv start res 0 len)
res))
-#;(define (deserialize-dhcp-message msg)
- (make <dhcp-message>
- #:op (bytevector-u8-ref msg 0)
- #:htype (bytevector-u8-ref msg 1)
- #:hops (bytevector-u8-ref msg 2)
- #:xid (bytevector-u32-ref msg 4 (endianness big))
- #:secs (bytevector-u16-ref msg 8 (endianness big))
- #:flags (bytevector-u16-ref msg 10 (endianness big))
- #:ciaddr (bytevector-u32-ref msg 12 (endianness big))
- #:yiaddr (bytevector-u32-ref msg 16 (endianness big))
- #:siaddr (bytevector-u32-ref msg 20 (endianness big))
- #:giaddr (bytevector-u32-ref msg 24 (endianness big))
- ; TODO: chaddr
- #:options (deserialize-options msg 240)))
+(define (deserialize-dhcp-msg msg)
+ (make-dhcp-msg
+ (bytevector-u8-ref msg 0) ; op
+ (bytevector-u8-ref msg 1) ; htype
+ (bytevector-u8-ref msg 2) ; hlen
+ (bytevector-u8-ref msg 3) ; hops
+ (bytevector-u32-ref msg 4 (endianness big)) ; xid
+ (bytevector-u16-ref msg 8 (endianness big)) ; secs
+ (bytevector-u16-ref msg 10 (endianness big)) ; flags
+ (bytevector-u32-ref msg 12 (endianness big)) ; ciaddr
+ (bytevector-u32-ref msg 16 (endianness big)) ; yiaddr
+ (bytevector-u32-ref msg 20 (endianness big)) ; siaddr
+ (bytevector-u32-ref msg 24 (endianness big)) ; giaddr
+ (bytevector-slice msg 28 16) ; chaddr
+ (bytevector-slice msg 44 64) ; sname
+ (bytevector-slice msg 108 128) ; file
+ (deserialize-options msg 240) ; options
+ ))
;; Set an <option> in a <dhcp-msg>.
(define-syntax-rule (set-option! msg opt)
@@ -224,13 +243,13 @@ from BV starting at index START"
;; Retrieve an option's value from a <dhcp-msg>
;; record MSG given its code CODE.
(define-syntax-rule (option-value msg code)
- (let* ((opts (slot-ref msg 'options))
+ (let* ((opts (dhcp-msg-options msg))
(opt (vector-ref opts code))
(val (dhcp-option-val opt)))
val))
;; Get the DHCP message type. See Section 9.6, RFC 2132.
-(define-syntax-rule (message-type msg)
+(define-syntax-rule (msg-type msg)
(option-value msg 53))
;; Map a DHCP message type to its single-digit code.
@@ -251,17 +270,18 @@ from BV starting at index START"
((eq? 'DHCPNAK type) 2)
(else 1))))
-(define (make-dhcp-msg netif type opts)
+(define (make-dhcp-message netif type opts)
"Make an instance of <dhcp-msg> for interface NETIF
with message type TYPE and options initialized to OPTS"
- (let* ((pair (net-iface-hwaddr netif))
+ (let* ((dhcp (net-iface-dhcp netif))
+ (pair (net-iface-hwaddr netif))
(chaddr (car pair))
(htype (cdr pair))
(hlen (bytevector-length chaddr))
(op (map-type-to-op type))
- (dhcp (net-iface-dhcp netif))
(msg-type-code (map-name-to-code
- 'DHCP-MSG-TYPE)))
+ 'DHCP-MESSAGE-TYPE))
+ (end-code (map-name-to-code 'END)))
(begin
(vector-set! opts
msg-type-code ; 53
@@ -319,7 +339,7 @@ ciaddr field in a <dhcp-msg> object."
;; TODO: figure out from 2131 exactly when to
;; return secs since config and when to return 0
-(define (retrieve-secs netif type)
+#;(define (retrieve-secs netif type)
"Given a <net-interface> NETIF and the message
type TYPE, return the appropriate value for the
secs field in a <dhcp-msg> object."
@@ -330,5 +350,8 @@ secs field in a <dhcp-msg> object."
(else (- (current-time) ; might need to change
(dhcp-config-start dhcp))))))
-(define-syntax-rule (make-dhcpdiscover netif opts)
- (make-dhcp-msg netif 'DHCPDISCOVER opts))
+(define (retrieve-secs netif type)
+ 0)
+
+(define (make-dhcpdiscover netif opts)
+ (make-dhcp-message netif 'DHCPDISCOVER opts))
diff --git a/tests/dhcp-messages.scm b/tests/dhcp-messages.scm
index ad0e4b7..5abca40 100644
--- a/tests/dhcp-messages.scm
+++ b/tests/dhcp-messages.scm
@@ -19,8 +19,10 @@
(use-modules (srfi srfi-64)
((guix build syscalls) #:select (all-network-interfaces))
- (dhcp interfaces)
(dhcp messages)
+ (dhcp interfaces)
+ (dhcp dhcp)
+ (dhcp options base)
(dhcp options names)
(rnrs bytevectors))
@@ -31,18 +33,35 @@
(all-network-interfaces)))
'DHCP-INIT))
-(define msg
+
+(define msg-type-code (map-name-to-code
+ 'DHCP-MESSAGE-TYPE))
+
+(define original
(make-dhcpdiscover netif (make-vector 256 #f)))
+(display (vector-ref (dhcp-msg-options original) 243))
+(newline) (newline)
+
(test-begin "dhcp-messages")
(test-eq "message-type"
(map-type-to-code 'DHCPDISCOVER)
- (bytevector-u8-ref (message-type msg) 0))
+ (bytevector-u8-ref (msg-type original) 0))
+
+(define serialized (serialize-dhcp-msg original))
+
+;(define opts (deserialize-options serialized 240))
+
+(define deserialized (deserialize-dhcp-msg serialized))
-(define serialized (serialize-dhcp-message msg))
+(test-eqv "fields-preserved-xid"
+ (dhcp-msg-xid deserialized)
+ (dhcp-msg-xid original))
-;(define deserialized (deserialize-dhcp-message msg))
+(test-equal "fields-preserved-options"
+ (dhcp-msg-options deserialized)
+ (dhcp-msg-options original))
(test-end)
- [dhcp] branch master updated (d1865d0 -> 0937fcf), Rohan Prinja, 2015/06/15
- [dhcp] 01/08: dhcp: remove trailing whitespace, Rohan Prinja, 2015/06/15
- [dhcp] 03/08: dhcp: correct copyright in tests/, Rohan Prinja, 2015/06/15
- [dhcp] 06/08: add copyright line from syscalls.scm in dhcp/interfaces, Rohan Prinja, 2015/06/15
- [dhcp] 02/08: dhcp: #nil -> #f, Rohan Prinja, 2015/06/15
- [dhcp] 04/08: dhcp: more tests for (dhcp interfaces), Rohan Prinja, 2015/06/15
- [dhcp] 05/08: more exports from dhcp/options/base and dhcp/dhcp, Rohan Prinja, 2015/06/15
- [dhcp] 07/08: remove unneeded FFI code from dhcp/interfaces.scm, Rohan Prinja, 2015/06/15
- [dhcp] 08/08: fix bugs in serializer and deserializer,
Rohan Prinja <=