1 files changed, 82 insertions, 0 deletions
diff --git a/src/util/inet_windowsize.c b/src/util/inet_windowsize.c
new file mode 100644
index 0000000..e982149
--- /dev/null
+++ b/src/util/inet_windowsize.c
@@ -0,0 +1,82 @@
+/*++
+/* NAME
+/*	inet_windowsize 3
+/* SUMMARY
+/*	TCP window scaling control
+/* SYNOPSIS
+/*	#include <iostuff.h>
+/*
+/*	int	inet_windowsize;
+/*
+/*	void	set_inet_windowsize(sock, windowsize)
+/*	int	sock;
+/*	int	windowsize;
+/* DESCRIPTION
+/*	set_inet_windowsize() overrides the default TCP window size
+/*	with the specified value. When called before listen() or
+/*	accept(), this works around broken infrastructure that
+/*	mis-handles TCP window scaling options.
+/*
+/*	The global inet_windowsize variable is available for other
+/*	routines to remember that they wish to override the default
+/*	TCP window size. The variable is not accessed by the
+/*	set_inet_windowsize() function itself.
+/*
+/*	Arguments:
+/* .IP sock
+/*	TCP communication endpoint, before the connect(2) or listen(2) call.
+/* .IP windowsize
+/*	The preferred TCP window size. This must be > 0.
+/* DIAGNOSTICS
+/*	Panic: interface violation.
+/*	Warnings: some error return from setsockopt().
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System libraries. */
+
+#include <sys_defs.h>
+#include <sys/socket.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <iostuff.h>
+
+/* Application storage. */
+
+ /*
+  * Tunable to work around broken routers.
+  */
+int     inet_windowsize = 0;
+
+/* set_inet_windowsize - set TCP send/receive window size */
+
+void    set_inet_windowsize(int sock, int windowsize)
+{
+
+    /*
+     * Sanity check.
+     */
+    if (windowsize <= 0)
+	msg_panic("inet_windowsize: bad window size %d", windowsize);
+
+    /*
+     * Generic implementation: set the send and receive buffer size before
+     * listen() or connect().
+     */
+    if (setsockopt(sock, SOL_SOCKET, SO_SNDBUF, (void *) &windowsize,
+		   sizeof(windowsize)) < 0)
+	msg_warn("setsockopt SO_SNDBUF %d: %m", windowsize);
+    if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF, (void *) &windowsize,
+		   sizeof(windowsize)) < 0)
+	msg_warn("setsockopt SO_RCVBUF %d: %m", windowsize);
+}