1 files changed, 104 insertions, 0 deletions
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
new file mode 100644
index 000000000000..557c9bf1a469
--- /dev/null
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
@@ -0,0 +1,104 @@
+/* Copyright (c) 2013-2017, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ * RMNET Data MAP protocol
+ *
+ */
+
+#include <linux/netdevice.h>
+#include "rmnet_config.h"
+#include "rmnet_map.h"
+#include "rmnet_private.h"
+
+#define RMNET_MAP_DEAGGR_SPACING  64
+#define RMNET_MAP_DEAGGR_HEADROOM (RMNET_MAP_DEAGGR_SPACING / 2)
+
+/* Adds MAP header to front of skb->data
+ * Padding is calculated and set appropriately in MAP header. Mux ID is
+ * initialized to 0.
+ */
+struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb,
+						  int hdrlen, int pad)
+{
+	struct rmnet_map_header *map_header;
+	u32 padding, map_datalen;
+	u8 *padbytes;
+
+	if (skb_headroom(skb) < sizeof(struct rmnet_map_header))
+		return NULL;
+
+	map_datalen = skb->len - hdrlen;
+	map_header = (struct rmnet_map_header *)
+			skb_push(skb, sizeof(struct rmnet_map_header));
+	memset(map_header, 0, sizeof(struct rmnet_map_header));
+
+	if (pad == RMNET_MAP_NO_PAD_BYTES) {
+		map_header->pkt_len = htons(map_datalen);
+		return map_header;
+	}
+
+	padding = ALIGN(map_datalen, 4) - map_datalen;
+
+	if (padding == 0)
+		goto done;
+
+	if (skb_tailroom(skb) < padding)
+		return NULL;
+
+	padbytes = (u8 *)skb_put(skb, padding);
+	memset(padbytes, 0, padding);
+
+done:
+	map_header->pkt_len = htons(map_datalen + padding);
+	map_header->pad_len = padding & 0x3F;
+
+	return map_header;
+}
+
+/* Deaggregates a single packet
+ * A whole new buffer is allocated for each portion of an aggregated frame.
+ * Caller should keep calling deaggregate() on the source skb until 0 is
+ * returned, indicating that there are no more packets to deaggregate. Caller
+ * is responsible for freeing the original skb.
+ */
+struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb)
+{
+	struct rmnet_map_header *maph;
+	struct sk_buff *skbn;
+	u32 packet_len;
+
+	if (skb->len == 0)
+		return NULL;
+
+	maph = (struct rmnet_map_header *)skb->data;
+	packet_len = ntohs(maph->pkt_len) + sizeof(struct rmnet_map_header);
+
+	if (((int)skb->len - (int)packet_len) < 0)
+		return NULL;
+
+	skbn = alloc_skb(packet_len + RMNET_MAP_DEAGGR_SPACING, GFP_ATOMIC);
+	if (!skbn)
+		return NULL;
+
+	skbn->dev = skb->dev;
+	skb_reserve(skbn, RMNET_MAP_DEAGGR_HEADROOM);
+	skb_put(skbn, packet_len);
+	memcpy(skbn->data, skb->data, packet_len);
+	skb_pull(skb, packet_len);
+
+	/* Some hardware can send us empty frames. Catch them */
+	if (ntohs(maph->pkt_len) == 0) {
+		kfree_skb(skb);
+		return NULL;
+	}
+
+	return skbn;
+}