1 files changed, 106 insertions, 0 deletions
diff --git a/fs/dlm/midcomms.c b/fs/dlm/midcomms.c
new file mode 100644
index 000000000..0bedfa860
--- /dev/null
+++ b/fs/dlm/midcomms.c
@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
+**
+**
+*******************************************************************************
+******************************************************************************/
+
+/*
+ * midcomms.c
+ *
+ * This is the appallingly named "mid-level" comms layer.
+ *
+ * Its purpose is to take packets from the "real" comms layer,
+ * split them up into packets and pass them to the interested
+ * part of the locking mechanism.
+ *
+ * It also takes messages from the locking layer, formats them
+ * into packets and sends them to the comms layer.
+ */
+
+#include <asm/unaligned.h>
+
+#include "dlm_internal.h"
+#include "lowcomms.h"
+#include "config.h"
+#include "lock.h"
+#include "midcomms.h"
+
+/*
+ * Called from the low-level comms layer to process a buffer of
+ * commands.
+ */
+
+int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int len)
+{
+	const unsigned char *ptr = buf;
+	const struct dlm_header *hd;
+	uint16_t msglen;
+	int ret = 0;
+
+	while (len >= sizeof(struct dlm_header)) {
+		hd = (struct dlm_header *)ptr;
+
+		/* no message should be more than this otherwise we
+		 * cannot deliver this message to upper layers
+		 */
+		msglen = get_unaligned_le16(&hd->h_length);
+		if (msglen > DEFAULT_BUFFER_SIZE ||
+		    msglen < sizeof(struct dlm_header)) {
+			log_print("received invalid length header: %u from node %d, will abort message parsing",
+				  msglen, nodeid);
+			return -EBADMSG;
+		}
+
+		/* caller will take care that leftover
+		 * will be parsed next call with more data
+		 */
+		if (msglen > len)
+			break;
+
+		switch (hd->h_cmd) {
+		case DLM_MSG:
+			if (msglen < sizeof(struct dlm_message)) {
+				log_print("dlm msg too small: %u, will skip this message",
+					  msglen);
+				goto skip;
+			}
+
+			break;
+		case DLM_RCOM:
+			if (msglen < sizeof(struct dlm_rcom)) {
+				log_print("dlm rcom msg too small: %u, will skip this message",
+					  msglen);
+				goto skip;
+			}
+
+			break;
+		default:
+			log_print("unsupported h_cmd received: %u, will skip this message",
+				  hd->h_cmd);
+			goto skip;
+		}
+
+		/* for aligned memory access, we just copy current message
+		 * to begin of the buffer which contains already parsed buffer
+		 * data and should provide align access for upper layers
+		 * because the start address of the buffer has a aligned
+		 * address. This memmove can be removed when the upperlayer
+		 * is capable of unaligned memory access.
+		 */
+		memmove(buf, ptr, msglen);
+		dlm_receive_buffer((union dlm_packet *)buf, nodeid);
+
+skip:
+		ret += msglen;
+		len -= msglen;
+		ptr += msglen;
+	}
+
+	return ret;
+}
+