1 files changed, 130 insertions, 0 deletions
diff --git a/net/dsa/tag_trailer.c b/net/dsa/tag_trailer.c
new file mode 100644
index 000000000000..d3117764b2c2
--- /dev/null
+++ b/net/dsa/tag_trailer.c
@@ -0,0 +1,130 @@
+/*
+ * net/dsa/tag_trailer.c - Trailer tag format handling
+ * Copyright (c) 2008 Marvell Semiconductor
+ *
+ * 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
+ * (at your option) any later version.
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/list.h>
+#include <linux/netdevice.h>
+#include "dsa_priv.h"
+
+int trailer_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct dsa_slave_priv *p = netdev_priv(dev);
+	struct sk_buff *nskb;
+	int padlen;
+	u8 *trailer;
+
+	dev->stats.tx_packets++;
+	dev->stats.tx_bytes += skb->len;
+
+	/*
+	 * We have to make sure that the trailer ends up as the very
+	 * last 4 bytes of the packet.  This means that we have to pad
+	 * the packet to the minimum ethernet frame size, if necessary,
+	 * before adding the trailer.
+	 */
+	padlen = 0;
+	if (skb->len < 60)
+		padlen = 60 - skb->len;
+
+	nskb = alloc_skb(NET_IP_ALIGN + skb->len + padlen + 4, GFP_ATOMIC);
+	if (nskb == NULL) {
+		kfree_skb(skb);
+		return NETDEV_TX_OK;
+	}
+	skb_reserve(nskb, NET_IP_ALIGN);
+
+	skb_reset_mac_header(nskb);
+	skb_set_network_header(nskb, skb_network_header(skb) - skb->head);
+	skb_set_transport_header(nskb, skb_transport_header(skb) - skb->head);
+	skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len));
+	kfree_skb(skb);
+
+	if (padlen) {
+		u8 *pad = skb_put(nskb, padlen);
+		memset(pad, 0, padlen);
+	}
+
+	trailer = skb_put(nskb, 4);
+	trailer[0] = 0x80;
+	trailer[1] = 1 << p->port;
+	trailer[2] = 0x10;
+	trailer[3] = 0x00;
+
+	nskb->protocol = htons(ETH_P_TRAILER);
+
+	nskb->dev = p->parent->master_netdev;
+	dev_queue_xmit(nskb);
+
+	return NETDEV_TX_OK;
+}
+
+static int trailer_rcv(struct sk_buff *skb, struct net_device *dev,
+		       struct packet_type *pt, struct net_device *orig_dev)
+{
+	struct dsa_switch *ds = dev->dsa_ptr;
+	u8 *trailer;
+	int source_port;
+
+	if (unlikely(ds == NULL))
+		goto out_drop;
+
+	skb = skb_unshare(skb, GFP_ATOMIC);
+	if (skb == NULL)
+		goto out;
+
+	if (skb_linearize(skb))
+		goto out_drop;
+
+	trailer = skb_tail_pointer(skb) - 4;
+	if (trailer[0] != 0x80 || (trailer[1] & 0xf8) != 0x00 ||
+	    (trailer[3] & 0xef) != 0x00 || trailer[3] != 0x00)
+		goto out_drop;
+
+	source_port = trailer[1] & 7;
+	if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL)
+		goto out_drop;
+
+	pskb_trim_rcsum(skb, skb->len - 4);
+
+	skb->dev = ds->ports[source_port];
+	skb_push(skb, ETH_HLEN);
+	skb->protocol = eth_type_trans(skb, skb->dev);
+
+	skb->dev->last_rx = jiffies;
+	skb->dev->stats.rx_packets++;
+	skb->dev->stats.rx_bytes += skb->len;
+
+	netif_receive_skb(skb);
+
+	return 0;
+
+out_drop:
+	kfree_skb(skb);
+out:
+	return 0;
+}
+
+static struct packet_type trailer_packet_type = {
+	.type	= __constant_htons(ETH_P_TRAILER),
+	.func	= trailer_rcv,
+};
+
+static int __init trailer_init_module(void)
+{
+	dev_add_pack(&trailer_packet_type);
+	return 0;
+}
+module_init(trailer_init_module);
+
+static void __exit trailer_cleanup_module(void)
+{
+	dev_remove_pack(&trailer_packet_type);
+}
+module_exit(trailer_cleanup_module);