1 files changed, 69 insertions, 0 deletions
diff --git a/roms/ipxe/src/net/iobpad.c b/roms/ipxe/src/net/iobpad.c
new file mode 100644
index 00000000..9cc8328e
--- /dev/null
+++ b/roms/ipxe/src/net/iobpad.c
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/**
+ * @file
+ *
+ * I/O buffer padding
+ *
+ */
+
+#include <string.h>
+#include <ipxe/iobuf.h>
+
+/**
+ * Pad I/O buffer
+ *
+ * @v iobuf		I/O buffer
+ * @v min_len		Minimum length
+ *
+ * This function pads and aligns I/O buffers, for devices that
+ * aren't capable of padding in hardware, or that require specific
+ * alignment in TX buffers.  The packet data will end up aligned to a
+ * multiple of @c IOB_ALIGN.
+ *
+ * @c min_len must not exceed @v IOB_ZLEN.
+ */
+void iob_pad ( struct io_buffer *iobuf, size_t min_len ) {
+	void *data;
+	size_t len;
+	size_t headroom;
+	signed int pad_len;
+
+	assert ( min_len <= IOB_ZLEN );
+
+	/* Move packet data to start of I/O buffer.  This will both
+	 * align the data (since I/O buffers are aligned to
+	 * IOB_ALIGN) and give us sufficient space for the
+	 * zero-padding
+	 */
+	data = iobuf->data;
+	len = iob_len ( iobuf );
+	headroom = iob_headroom ( iobuf );
+	iob_push ( iobuf, headroom );
+	memmove ( iobuf->data, data, len );
+	iob_unput ( iobuf, headroom );
+
+	/* Pad to minimum packet length */
+	pad_len = ( min_len - iob_len ( iobuf ) );
+	if ( pad_len > 0 )
+		memset ( iob_put ( iobuf, pad_len ), 0, pad_len );
+}