From 757656573a11bcaab840e9d6be228109fdb3ec44 Mon Sep 17 00:00:00 2001
From: Quentin <quentin@deuxfleurs.fr>
Date: Thu, 9 Jul 2020 15:59:25 +0200
Subject: [PATCH] A first step to query UDP

---
 bindings/libc.scm       | 37 +++++++++++++++++++++++++++++++++----
 examples/udp_server.scm | 36 +++++++++++++++++++++++++++++++++++-
 2 files changed, 68 insertions(+), 5 deletions(-)

diff --git a/bindings/libc.scm b/bindings/libc.scm
index cc8ee6f..255ae43 100644
--- a/bindings/libc.scm
+++ b/bindings/libc.scm
@@ -63,11 +63,19 @@
     (domain->int af)
     src dst))
 
-(define (htons host)
+(define (inet_ntop af src dst size)
   ((foreign-procedure
-     "htons"
-     (short)
-     short) host))
+     "inet_ntop"
+     (int void* (* char) int)
+     void*)
+     (domain->int af)
+     src dst size))
+
+(define (htons host)
+  ((foreign-procedure "htons" (short) short) host))
+
+(define (ntohs net)
+  ((foreign-procedure "ntohs" (short) short) net))
 
 (define (setsockopt sockfd level optname optval optlen)
   ((foreign-procedure
@@ -85,4 +93,25 @@
      (int void* int)
      int) sockfd address address_len))
 
+(define (listen sockfd backlog)
+  ((foreign-procedure
+     "listen"
+     (int int)
+     int) sockfd backlog))
 
+(define (msgflag->int flag)
+  (case flag
+    ((MSG_DEFAULT) 0)
+))
+
+(define (recvfrom sockfd buf len msgflag src-addr addrlen)
+  ((foreign-procedure
+     "recvfrom"
+     (int void* int int (* sockaddr_in) (* int))
+     int)
+    sockfd
+    buf
+    len
+    (msgflag->int msgflag)
+    src-addr
+    addrlen))
diff --git a/examples/udp_server.scm b/examples/udp_server.scm
index 4ac9121..a24c903 100644
--- a/examples/udp_server.scm
+++ b/examples/udp_server.scm
@@ -51,8 +51,42 @@
           (ftype-pointer-address addr)
           (ftype-sizeof sockaddr_in))))))
 
+(define (udpsock-readblock sock fx)
+  (let* 
+    ([bufsize 1500] [straddrsize 255]
+     [buf (foreign-alloc bufsize)]
+     [straddr (make-ftype-pointer 
+                char
+                (foreign-alloc straddrsize))]
+     [addrlen (make-ftype-pointer 
+                int 
+                (foreign-alloc (ftype-sizeof int)))]
+     [addr (make-ftype-pointer 
+             sockaddr_in 
+             (foreign-alloc (ftype-sizeof sockaddr_in)))]
+     [nread (recvfrom sock buf bufsize 'MSG_DEFAULT addr addrlen)])
+
+    ; FIXME add a loop and check fx output to know if we continue
+    (fx
+      (inet_ntop 
+        'AF_INET 
+        (ftype-pointer-address
+          (ftype-&ref sockaddr_in (sin_addr) addr))
+        straddr
+        straddrsize)
+      (ntohs (ftype-ref sockaddr_in (sin_port) addr))
+      buf nread)
+
+    (foreign-free (ftype-pointer-address straddr))
+    (foreign-free (ftype-pointer-address addrlen))
+    (foreign-free (ftype-pointer-address addr))
+    (foreign-free buf)))
+
 (udpsock-create
   (lambda (sock)
     (udpsock-reuseaddr sock)
     (udpsock-bind sock "0.0.0.0" 1337)
-    (printf "~a~%" sock)))
+    (udpsock-readblock 
+      sock 
+      (lambda (host port buf size)
+))))