From 1c042093288d206430133414c109e40f5abb556e Mon Sep 17 00:00:00 2001
From: Milo <iitalics@gmail.com>
Date: Thu, 30 Jan 2020 19:45:14 -0500
Subject: [PATCH] message parsing

---
 msg.rkt | 98 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 msg.rkt

diff --git a/msg.rkt b/msg.rkt
new file mode 100644
index 0000000..7f252b6
--- /dev/null
+++ b/msg.rkt
@@ -0,0 +1,98 @@
+#lang racket
+(provide (all-defined-out))
+
+(require json
+         "iputil.rkt")
+
+;; src, dst : IP
+;; data : Any
+(struct msg [src dst]
+  #:transparent)
+
+(struct msg:update msg [subnet pref self-origin? as-path origin]
+  ;; subnet : Subnet
+  ;; pref : Int
+  ;; self-origin? : Boolean
+  ;; as-path : [Listof Int]
+  ;; origin : (U 'IGP 'EGP 'UNK)
+  #:transparent)
+
+(struct msg:revoke msg [networks]
+  ;; networks : [Listof Subnet]
+  #:transparent)
+
+(struct msg:data msg [stuff]
+  ;; stuff : Any
+  #:transparent)
+
+(struct msg:no-route msg []
+  #:transparent)
+
+(struct msg:dump msg []
+  #:transparent)
+
+(struct msg:table msg [networks]
+  ;; networks : [Listof [List Subnet IP]]
+  #:transparent)
+
+;; Msg -> String
+(define (msg-type m)
+  (cond
+    [(msg:update? m) "update"]
+    [(msg:revoke? m) "revoke"]
+    [(msg:data? m) "data"]
+    [(msg:no-route? m) "no route"]
+    [(msg:dump? m) "dump"]
+    [(msg:table? m) "table"]))
+
+;; Any -> Msg
+(define (jsexpr->msg j)
+  (define src (string->ip (hash-ref j 'src)))
+  (define dst (string->ip (hash-ref j 'dst)))
+  (define type (hash-ref j 'type))
+  (define data (hash-ref j 'msg))
+
+  (define (hash->subnet h)
+    (subnet (string->ip (hash-ref h 'network))
+            (ip-netmask (string->ip (hash-ref h 'netmask)))))
+
+  (match type
+    ["update"
+     (msg:update src dst
+                 (hash->subnet data)
+                 (hash-ref data 'localpref)
+                 (hash-ref data 'selfOrigin)
+                 (hash-ref data 'ASPath)
+                 (string->symbol (hash-ref data 'origin)))]
+    ["revoke"
+     (msg:revoke src dst
+                 (map hash->subnet data))]
+    ["data"
+     (msg:data src dst
+               data)]
+    ["no route"
+     (msg:no-route src dst)]
+    ["dump"
+     (msg:dump src dst)]
+    ["table"
+     (msg:table src dst
+                (map (λ (h) (list (hash->subnet h)
+                                  (string->ip (hash-ref h 'peer))))
+                     data))]))
+
+;; Bytes -> Msg
+(define (bytes->msg bs)
+  (bytes->jsexpr
+   (jsexpr->msg bs)))
+
+(module+ test
+  (jsexpr->msg
+   (hash 'src "1.2.3.4"
+         'dst "1.2.3.7"
+         'type "update"
+         'msg (hash 'network "1.2.3.5"
+                    'netmask "255.255.255.128"
+                    'localpref 100
+                    'selfOrigin #t
+                    'ASPath '(1 2)
+                    'origin "UNK"))))