[linux-2.6-block.git] / net / dsa / tag_edsa.c

/*
 * net/dsa/tag_edsa.c - Ethertype DSA tagging
 * Copyright (c) 2008-2009 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/slab.h>
#include "dsa_priv.h"

#define DSA_HLEN	4
#define EDSA_HLEN	8

static netdev_tx_t edsa_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct dsa_slave_priv *p = netdev_priv(dev);
	u8 *edsa_header;

	dev->stats.tx_packets++;
	dev->stats.tx_bytes += skb->len;

	/*
	 * Convert the outermost 802.1q tag to a DSA tag and prepend
	 * a DSA ethertype field is the packet is tagged, or insert
	 * a DSA ethertype plus DSA tag between the addresses and the
	 * current ethertype field if the packet is untagged.
	 */
	if (skb->protocol == htons(ETH_P_8021Q)) {
		if (skb_cow_head(skb, DSA_HLEN) < 0)
			goto out_free;
		skb_push(skb, DSA_HLEN);

		memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN);

		/*
		 * Construct tagged FROM_CPU DSA tag from 802.1q tag.
		 */
		edsa_header = skb->data + 2 * ETH_ALEN;
		edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff;
		edsa_header[1] = ETH_P_EDSA & 0xff;
		edsa_header[2] = 0x00;
		edsa_header[3] = 0x00;
		edsa_header[4] = 0x60 | p->parent->index;
		edsa_header[5] = p->port << 3;

		/*
		 * Move CFI field from byte 6 to byte 5.
		 */
		if (edsa_header[6] & 0x10) {
			edsa_header[5] |= 0x01;
			edsa_header[6] &= ~0x10;
		}
	} else {
		if (skb_cow_head(skb, EDSA_HLEN) < 0)
			goto out_free;
		skb_push(skb, EDSA_HLEN);

		memmove(skb->data, skb->data + EDSA_HLEN, 2 * ETH_ALEN);

		/*
		 * Construct untagged FROM_CPU DSA tag.
		 */
		edsa_header = skb->data + 2 * ETH_ALEN;
		edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff;
		edsa_header[1] = ETH_P_EDSA & 0xff;
		edsa_header[2] = 0x00;
		edsa_header[3] = 0x00;
		edsa_header[4] = 0x40 | p->parent->index;
		edsa_header[5] = p->port << 3;
		edsa_header[6] = 0x00;
		edsa_header[7] = 0x00;
	}

	skb->dev = p->parent->dst->master_netdev;
	dev_queue_xmit(skb);

	return NETDEV_TX_OK;

out_free:
	kfree_skb(skb);
	return NETDEV_TX_OK;
}

static int edsa_rcv(struct sk_buff *skb, struct net_device *dev,
		    struct packet_type *pt, struct net_device *orig_dev)
{
	struct dsa_switch_tree *dst = dev->dsa_ptr;
	struct dsa_switch *ds;
	u8 *edsa_header;
	int source_device;
	int source_port;

	if (unlikely(dst == NULL))
		goto out_drop;

	skb = skb_unshare(skb, GFP_ATOMIC);
	if (skb == NULL)
		goto out;

	if (unlikely(!pskb_may_pull(skb, EDSA_HLEN)))
		goto out_drop;

	/*
	 * Skip the two null bytes after the ethertype.
	 */
	edsa_header = skb->data + 2;

	/*
	 * Check that frame type is either TO_CPU or FORWARD.
	 */
	if ((edsa_header[0] & 0xc0) != 0x00 && (edsa_header[0] & 0xc0) != 0xc0)
		goto out_drop;

	/*
	 * Determine source device and port.
	 */
	source_device = edsa_header[0] & 0x1f;
	source_port = (edsa_header[1] >> 3) & 0x1f;

	/*
	 * Check that the source device exists and that the source
	 * port is a registered DSA port.
	 */
	if (source_device >= dst->pd->nr_chips)
		goto out_drop;
	ds = dst->ds[source_device];
	if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL)
		goto out_drop;

	/*
	 * If the 'tagged' bit is set, convert the DSA tag to a 802.1q
	 * tag and delete the ethertype part.  If the 'tagged' bit is
	 * clear, delete the ethertype and the DSA tag parts.
	 */
	if (edsa_header[0] & 0x20) {
		u8 new_header[4];

		/*
		 * Insert 802.1q ethertype and copy the VLAN-related
		 * fields, but clear the bit that will hold CFI (since
		 * DSA uses that bit location for another purpose).
		 */
		new_header[0] = (ETH_P_8021Q >> 8) & 0xff;
		new_header[1] = ETH_P_8021Q & 0xff;
		new_header[2] = edsa_header[2] & ~0x10;
		new_header[3] = edsa_header[3];

		/*
		 * Move CFI bit from its place in the DSA header to
		 * its 802.1q-designated place.
		 */
		if (edsa_header[1] & 0x01)
			new_header[2] |= 0x10;

		skb_pull_rcsum(skb, DSA_HLEN);

		/*
		 * Update packet checksum if skb is CHECKSUM_COMPLETE.
		 */
		if (skb->ip_summed == CHECKSUM_COMPLETE) {
			__wsum c = skb->csum;
			c = csum_add(c, csum_partial(new_header + 2, 2, 0));
			c = csum_sub(c, csum_partial(edsa_header + 2, 2, 0));
			skb->csum = c;
		}

		memcpy(edsa_header, new_header, DSA_HLEN);

		memmove(skb->data - ETH_HLEN,
			skb->data - ETH_HLEN - DSA_HLEN,
			2 * ETH_ALEN);
	} else {
		/*
		 * Remove DSA tag and update checksum.
		 */
		skb_pull_rcsum(skb, EDSA_HLEN);
		memmove(skb->data - ETH_HLEN,
			skb->data - ETH_HLEN - EDSA_HLEN,
			2 * ETH_ALEN);
	}

	skb->dev = ds->ports[source_port];
	skb_push(skb, ETH_HLEN);
	skb->pkt_type = PACKET_HOST;
	skb->protocol = eth_type_trans(skb, skb->dev);

	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;
}

const struct dsa_device_ops edsa_netdev_ops = {
	.xmit	= edsa_xmit,
	.rcv	= edsa_rcv,
};
Commit	Line	Data
91da11f8 LB	1	/*
91da11f8 LB	2	* net/dsa/tag_edsa.c - Ethertype DSA tagging
e84665c9	3	* Copyright (c) 2008-2009 Marvell Semiconductor
91da11f8 LB	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License as published by
	7	* the Free Software Foundation; either version 2 of the License, or
	8	* (at your option) any later version.
	9	*/
	10
	11	#include <linux/etherdevice.h>
	12	#include <linux/list.h>
5a0e3ad6	13	#include <linux/slab.h>
91da11f8 LB	14	#include "dsa_priv.h"
	15
	16	#define DSA_HLEN 4
	17	#define EDSA_HLEN 8
	18
3e8a72d1	19	static netdev_tx_t edsa_xmit(struct sk_buff skb, struct net_device dev)
91da11f8 LB	20	{
	21	struct dsa_slave_priv *p = netdev_priv(dev);
	22	u8 *edsa_header;
	23
	24	dev->stats.tx_packets++;
	25	dev->stats.tx_bytes += skb->len;
	26
	27	/*
	28	* Convert the outermost 802.1q tag to a DSA tag and prepend
	29	* a DSA ethertype field is the packet is tagged, or insert
	30	* a DSA ethertype plus DSA tag between the addresses and the
	31	* current ethertype field if the packet is untagged.
	32	*/
	33	if (skb->protocol == htons(ETH_P_8021Q)) {
	34	if (skb_cow_head(skb, DSA_HLEN) < 0)
	35	goto out_free;
	36	skb_push(skb, DSA_HLEN);
	37
	38	memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN);
	39
	40	/*
	41	* Construct tagged FROM_CPU DSA tag from 802.1q tag.
	42	*/
	43	edsa_header = skb->data + 2 * ETH_ALEN;
	44	edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff;
	45	edsa_header[1] = ETH_P_EDSA & 0xff;
	46	edsa_header[2] = 0x00;
	47	edsa_header[3] = 0x00;
e84665c9	48	edsa_header[4] = 0x60 \| p->parent->index;
91da11f8 LB	49	edsa_header[5] = p->port << 3;
	50
	51	/*
	52	* Move CFI field from byte 6 to byte 5.
	53	*/
	54	if (edsa_header[6] & 0x10) {
	55	edsa_header[5] \|= 0x01;
	56	edsa_header[6] &= ~0x10;
	57	}
	58	} else {
	59	if (skb_cow_head(skb, EDSA_HLEN) < 0)
	60	goto out_free;
	61	skb_push(skb, EDSA_HLEN);
	62
	63	memmove(skb->data, skb->data + EDSA_HLEN, 2 * ETH_ALEN);
	64
	65	/*
	66	* Construct untagged FROM_CPU DSA tag.
	67	*/
	68	edsa_header = skb->data + 2 * ETH_ALEN;
	69	edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff;
	70	edsa_header[1] = ETH_P_EDSA & 0xff;
	71	edsa_header[2] = 0x00;
	72	edsa_header[3] = 0x00;
e84665c9	73	edsa_header[4] = 0x40 \| p->parent->index;
91da11f8 LB	74	edsa_header[5] = p->port << 3;
	75	edsa_header[6] = 0x00;
	76	edsa_header[7] = 0x00;
	77	}
	78
e84665c9	79	skb->dev = p->parent->dst->master_netdev;
91da11f8 LB	80	dev_queue_xmit(skb);
	81
	82	return NETDEV_TX_OK;
	83
	84	out_free:
	85	kfree_skb(skb);
	86	return NETDEV_TX_OK;
	87	}
	88
	89	static int edsa_rcv(struct sk_buff skb, struct net_device dev,
	90	struct packet_type pt, struct net_device orig_dev)
	91	{
e84665c9 LB	92	struct dsa_switch_tree *dst = dev->dsa_ptr;
e84665c9 LB	93	struct dsa_switch *ds;
91da11f8	94	u8 *edsa_header;
e84665c9	95	int source_device;
91da11f8 LB	96	int source_port;
91da11f8 LB	97
e84665c9	98	if (unlikely(dst == NULL))
91da11f8 LB	99	goto out_drop;
	100
	101	skb = skb_unshare(skb, GFP_ATOMIC);
	102	if (skb == NULL)
	103	goto out;
	104
	105	if (unlikely(!pskb_may_pull(skb, EDSA_HLEN)))
	106	goto out_drop;
	107
	108	/*
	109	* Skip the two null bytes after the ethertype.
	110	*/
	111	edsa_header = skb->data + 2;
	112
	113	/*
e84665c9	114	* Check that frame type is either TO_CPU or FORWARD.
91da11f8	115	*/
e84665c9	116	if ((edsa_header[0] & 0xc0) != 0x00 && (edsa_header[0] & 0xc0) != 0xc0)
91da11f8 LB	117	goto out_drop;
	118
	119	/*
e84665c9	120	* Determine source device and port.
91da11f8	121	*/
e84665c9	122	source_device = edsa_header[0] & 0x1f;
91da11f8	123	source_port = (edsa_header[1] >> 3) & 0x1f;
e84665c9 LB	124
	125	/*
	126	* Check that the source device exists and that the source
	127	* port is a registered DSA port.
	128	*/
	129	if (source_device >= dst->pd->nr_chips)
	130	goto out_drop;
	131	ds = dst->ds[source_device];
91da11f8 LB	132	if (source_port >= DSA_MAX_PORTS \|\| ds->ports[source_port] == NULL)
	133	goto out_drop;
	134
	135	/*
	136	* If the 'tagged' bit is set, convert the DSA tag to a 802.1q
	137	* tag and delete the ethertype part. If the 'tagged' bit is
	138	* clear, delete the ethertype and the DSA tag parts.
	139	*/
	140	if (edsa_header[0] & 0x20) {
	141	u8 new_header[4];
	142
	143	/*
	144	* Insert 802.1q ethertype and copy the VLAN-related
	145	* fields, but clear the bit that will hold CFI (since
	146	* DSA uses that bit location for another purpose).
	147	*/
	148	new_header[0] = (ETH_P_8021Q >> 8) & 0xff;
	149	new_header[1] = ETH_P_8021Q & 0xff;
	150	new_header[2] = edsa_header[2] & ~0x10;
	151	new_header[3] = edsa_header[3];
	152
	153	/*
	154	* Move CFI bit from its place in the DSA header to
	155	* its 802.1q-designated place.
	156	*/
	157	if (edsa_header[1] & 0x01)
	158	new_header[2] \|= 0x10;
	159
	160	skb_pull_rcsum(skb, DSA_HLEN);
	161
	162	/*
	163	* Update packet checksum if skb is CHECKSUM_COMPLETE.
	164	*/
	165	if (skb->ip_summed == CHECKSUM_COMPLETE) {
	166	__wsum c = skb->csum;
	167	c = csum_add(c, csum_partial(new_header + 2, 2, 0));
	168	c = csum_sub(c, csum_partial(edsa_header + 2, 2, 0));
	169	skb->csum = c;
	170	}
	171
	172	memcpy(edsa_header, new_header, DSA_HLEN);
	173
	174	memmove(skb->data - ETH_HLEN,
	175	skb->data - ETH_HLEN - DSA_HLEN,
	176	2 * ETH_ALEN);
	177	} else {
	178	/*
	179	* Remove DSA tag and update checksum.
	180	*/
	181	skb_pull_rcsum(skb, EDSA_HLEN);
	182	memmove(skb->data - ETH_HLEN,
	183	skb->data - ETH_HLEN - EDSA_HLEN,
	184	2 * ETH_ALEN);
	185	}
	186
	187	skb->dev = ds->ports[source_port];
	188	skb_push(skb, ETH_HLEN);
14ee6742	189	skb->pkt_type = PACKET_HOST;
91da11f8 LB	190	skb->protocol = eth_type_trans(skb, skb->dev);
91da11f8 LB	191
91da11f8 LB	192	skb->dev->stats.rx_packets++;
	193	skb->dev->stats.rx_bytes += skb->len;
	194
	195	netif_receive_skb(skb);
	196
	197	return 0;
	198
	199	out_drop:
	200	kfree_skb(skb);
	201	out:
	202	return 0;
	203	}
	204
3e8a72d1 FF	205	const struct dsa_device_ops edsa_netdev_ops = {
	206	.xmit = edsa_xmit,
	207	.rcv = edsa_rcv,
91da11f8	208	};