adding get-socket-option and set-socket-option!

lib/chibi/net.scm

@@ -65,7 +65,8 @@
 ;;> Convenience wrapper to call socket, bind and listen to return
 ;;> a socket suitable for accepting connections on the given
 ;;> @var{addrinfo}.  @var{max-conn} is the maximum number of pending
-;;> connections, and defaults to 128.
+;;> connections, and defaults to 128.  Automatically specifies
+;;> @scheme{socket-opt/reuseaddr}.
 
 (define (make-listener-socket addrinfo . o)
   (let* ((max-connections (if (pair? o) (car o) 128))
@@ -75,6 +76,8 @@
     (cond
      ((negative? sock)
       (error "couldn't create socket for: " addrinfo))
+     ((not (set-socket-option! sock level/socket socket-opt/reuseaddr 1))
+      (error "couldn't set the socket to be reusable" addrinfo))
      ((negative? (bind sock
                        (address-info-address addrinfo)
                        (address-info-address-length addrinfo)))
@@ -85,3 +88,12 @@
       (error "couldn't listen on socket for: " addrinfo))
      (else
       sock))))
+
+;;> Returns the socket option of the given @var{name} for @var{socket}.
+;;> @var{socket} should be a file descriptor, level the constant
+;;> @scheme{level/socket}, and name one of the constants beginning with
+;;> "socket-opt/".
+
+(define (get-socket-option socket level name)
+  (let ((res (getsockopt socket level name)))
+    (and (pair? res) (car res))))

lib/chibi/net.sld

@@ -7,7 +7,12 @@
           address-info-address address-info-address-length address-info-next
           address-family/unix address-family/inet
           socket-type/stream socket-type/datagram socket-type/raw
-          ip-proto/tcp ip-proto/udp)
+          ip-proto/tcp ip-proto/udp
+          get-socket-option set-socket-option! level/socket
+          socket-opt/debug socket-opt/broadcast socket-opt/reuseaddr
+          socket-opt/keepalive socket-opt/oobinline socket-opt/sndbuf
+          socket-opt/rcvbuf socket-opt/dontroute socket-opt/rcvlowat
+          socket-opt/sndlowat)
   (import (scheme) (chibi filesystem))
   (include-shared "net")
   (include "net.scm"))

lib/chibi/net.stub

@@ -60,3 +60,30 @@
 ;;/
 
 (c-include "accept.c")
+
+(define-c errno getsockopt
+  (int int int (result int) (result (value (sizeof int) socklen_t))))
+
+;;> Set an option for the given socket.  For example, to make the
+;;> address reusable:
+;;> @scheme{(set-socket-option! sock level/socket socket-opt/reuseaddr 1)}
+
+(define-c errno (set-socket-option! "setsockopt")
+  (int int int (pointer int) (value (sizeof int) socklen_t)))
+
+(define-c-const int (level/socket "SOL_SOCKET"))
+
+(define-c-const int (socket-opt/debug "SO_DEBUG"))
+(define-c-const int (socket-opt/broadcast "SO_BROADCAST"))
+(define-c-const int (socket-opt/reuseaddr "SO_REUSEADDR"))
+(define-c-const int (socket-opt/keepalive "SO_KEEPALIVE"))
+(define-c-const int (socket-opt/oobinline "SO_OOBINLINE"))
+(define-c-const int (socket-opt/sndbuf "SO_SNDBUF"))
+(define-c-const int (socket-opt/rcvbuf "SO_RCVBUF"))
+(define-c-const int (socket-opt/dontroute "SO_DONTROUTE"))
+(define-c-const int (socket-opt/rcvlowat "SO_RCVLOWAT"))
+(define-c-const int (socket-opt/sndlowat "SO_SNDLOWAT"))
+
+;;> The constants for the @scheme{get-socket-option} and
+;;> @scheme{set-socket-option!}.
+;;/