[linux.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/netdevice.h>
#include <linux/slab.h>
#include "dsa_priv.h"

#define DSA_HLEN	4
#define EDSA_HLEN	8

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->protocol = htons(ETH_P_EDSA);

	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;
}

static struct packet_type edsa_packet_type __read_mostly = {
	.type	= cpu_to_be16(ETH_P_EDSA),
	.func	= edsa_rcv,
};

static int __init edsa_init_module(void)
{
	dev_add_pack(&edsa_packet_type);
	return 0;
}
module_init(edsa_init_module);

static void __exit edsa_cleanup_module(void)
{
	dev_remove_pack(&edsa_packet_type);
}
module_exit(edsa_cleanup_module);
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>
	13	#include <linux/netdevice.h>
5a0e3ad6	14	#include <linux/slab.h>
91da11f8 LB	15	#include "dsa_priv.h"
	16
	17	#define DSA_HLEN 4
	18	#define EDSA_HLEN 8
	19
6fef4c0c	20	netdev_tx_t edsa_xmit(struct sk_buff skb, struct net_device dev)
91da11f8 LB	21	{
	22	struct dsa_slave_priv *p = netdev_priv(dev);
	23	u8 *edsa_header;
	24
	25	dev->stats.tx_packets++;
	26	dev->stats.tx_bytes += skb->len;
	27
	28	/*
	29	* Convert the outermost 802.1q tag to a DSA tag and prepend
	30	* a DSA ethertype field is the packet is tagged, or insert
	31	* a DSA ethertype plus DSA tag between the addresses and the
	32	* current ethertype field if the packet is untagged.
	33	*/
	34	if (skb->protocol == htons(ETH_P_8021Q)) {
	35	if (skb_cow_head(skb, DSA_HLEN) < 0)
	36	goto out_free;
	37	skb_push(skb, DSA_HLEN);
	38
	39	memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN);
	40
	41	/*
	42	* Construct tagged FROM_CPU DSA tag from 802.1q tag.
	43	*/
	44	edsa_header = skb->data + 2 * ETH_ALEN;
	45	edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff;
	46	edsa_header[1] = ETH_P_EDSA & 0xff;
	47	edsa_header[2] = 0x00;
	48	edsa_header[3] = 0x00;
e84665c9	49	edsa_header[4] = 0x60 \| p->parent->index;
91da11f8 LB	50	edsa_header[5] = p->port << 3;
	51
	52	/*
	53	* Move CFI field from byte 6 to byte 5.
	54	*/
	55	if (edsa_header[6] & 0x10) {
	56	edsa_header[5] \|= 0x01;
	57	edsa_header[6] &= ~0x10;
	58	}
	59	} else {
	60	if (skb_cow_head(skb, EDSA_HLEN) < 0)
	61	goto out_free;
	62	skb_push(skb, EDSA_HLEN);
	63
	64	memmove(skb->data, skb->data + EDSA_HLEN, 2 * ETH_ALEN);
	65
	66	/*
	67	* Construct untagged FROM_CPU DSA tag.
	68	*/
	69	edsa_header = skb->data + 2 * ETH_ALEN;
	70	edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff;
	71	edsa_header[1] = ETH_P_EDSA & 0xff;
	72	edsa_header[2] = 0x00;
	73	edsa_header[3] = 0x00;
e84665c9	74	edsa_header[4] = 0x40 \| p->parent->index;
91da11f8 LB	75	edsa_header[5] = p->port << 3;
	76	edsa_header[6] = 0x00;
	77	edsa_header[7] = 0x00;
	78	}
	79
	80	skb->protocol = htons(ETH_P_EDSA);
	81
e84665c9	82	skb->dev = p->parent->dst->master_netdev;
91da11f8 LB	83	dev_queue_xmit(skb);
	84
	85	return NETDEV_TX_OK;
	86
	87	out_free:
	88	kfree_skb(skb);
	89	return NETDEV_TX_OK;
	90	}
	91
	92	static int edsa_rcv(struct sk_buff skb, struct net_device dev,
	93	struct packet_type pt, struct net_device orig_dev)
	94	{
e84665c9 LB	95	struct dsa_switch_tree *dst = dev->dsa_ptr;
e84665c9 LB	96	struct dsa_switch *ds;
91da11f8	97	u8 *edsa_header;
e84665c9	98	int source_device;
91da11f8 LB	99	int source_port;
91da11f8 LB	100
e84665c9	101	if (unlikely(dst == NULL))
91da11f8 LB	102	goto out_drop;
	103
	104	skb = skb_unshare(skb, GFP_ATOMIC);
	105	if (skb == NULL)
	106	goto out;
	107
	108	if (unlikely(!pskb_may_pull(skb, EDSA_HLEN)))
	109	goto out_drop;
	110
	111	/*
	112	* Skip the two null bytes after the ethertype.
	113	*/
	114	edsa_header = skb->data + 2;
	115
	116	/*
e84665c9	117	* Check that frame type is either TO_CPU or FORWARD.
91da11f8	118	*/
e84665c9	119	if ((edsa_header[0] & 0xc0) != 0x00 && (edsa_header[0] & 0xc0) != 0xc0)
91da11f8 LB	120	goto out_drop;
	121
	122	/*
e84665c9	123	* Determine source device and port.
91da11f8	124	*/
e84665c9	125	source_device = edsa_header[0] & 0x1f;
91da11f8	126	source_port = (edsa_header[1] >> 3) & 0x1f;
e84665c9 LB	127
	128	/*
	129	* Check that the source device exists and that the source
	130	* port is a registered DSA port.
	131	*/
	132	if (source_device >= dst->pd->nr_chips)
	133	goto out_drop;
	134	ds = dst->ds[source_device];
91da11f8 LB	135	if (source_port >= DSA_MAX_PORTS \|\| ds->ports[source_port] == NULL)
	136	goto out_drop;
	137
	138	/*
	139	* If the 'tagged' bit is set, convert the DSA tag to a 802.1q
	140	* tag and delete the ethertype part. If the 'tagged' bit is
	141	* clear, delete the ethertype and the DSA tag parts.
	142	*/
	143	if (edsa_header[0] & 0x20) {
	144	u8 new_header[4];
	145
	146	/*
	147	* Insert 802.1q ethertype and copy the VLAN-related
	148	* fields, but clear the bit that will hold CFI (since
	149	* DSA uses that bit location for another purpose).
	150	*/
	151	new_header[0] = (ETH_P_8021Q >> 8) & 0xff;
	152	new_header[1] = ETH_P_8021Q & 0xff;
	153	new_header[2] = edsa_header[2] & ~0x10;
	154	new_header[3] = edsa_header[3];
	155
	156	/*
	157	* Move CFI bit from its place in the DSA header to
	158	* its 802.1q-designated place.
	159	*/
	160	if (edsa_header[1] & 0x01)
	161	new_header[2] \|= 0x10;
	162
	163	skb_pull_rcsum(skb, DSA_HLEN);
	164
	165	/*
	166	* Update packet checksum if skb is CHECKSUM_COMPLETE.
	167	*/
	168	if (skb->ip_summed == CHECKSUM_COMPLETE) {
	169	__wsum c = skb->csum;
	170	c = csum_add(c, csum_partial(new_header + 2, 2, 0));
	171	c = csum_sub(c, csum_partial(edsa_header + 2, 2, 0));
	172	skb->csum = c;
	173	}
	174
	175	memcpy(edsa_header, new_header, DSA_HLEN);
	176
	177	memmove(skb->data - ETH_HLEN,
	178	skb->data - ETH_HLEN - DSA_HLEN,
	179	2 * ETH_ALEN);
	180	} else {
	181	/*
	182	* Remove DSA tag and update checksum.
	183	*/
	184	skb_pull_rcsum(skb, EDSA_HLEN);
	185	memmove(skb->data - ETH_HLEN,
	186	skb->data - ETH_HLEN - EDSA_HLEN,
	187	2 * ETH_ALEN);
	188	}
	189
	190	skb->dev = ds->ports[source_port];
	191	skb_push(skb, ETH_HLEN);
14ee6742	192	skb->pkt_type = PACKET_HOST;
91da11f8 LB	193	skb->protocol = eth_type_trans(skb, skb->dev);
91da11f8 LB	194
91da11f8 LB	195	skb->dev->stats.rx_packets++;
	196	skb->dev->stats.rx_bytes += skb->len;
	197
	198	netif_receive_skb(skb);
	199
	200	return 0;
	201
	202	out_drop:
	203	kfree_skb(skb);
	204	out:
	205	return 0;
	206	}
	207
7546dd97	208	static struct packet_type edsa_packet_type __read_mostly = {
09640e63	209	.type = cpu_to_be16(ETH_P_EDSA),
91da11f8 LB	210	.func = edsa_rcv,
	211	};
	212
	213	static int __init edsa_init_module(void)
	214	{
	215	dev_add_pack(&edsa_packet_type);
	216	return 0;
	217	}
	218	module_init(edsa_init_module);
	219
	220	static void __exit edsa_cleanup_module(void)
	221	{
	222	dev_remove_pack(&edsa_packet_type);
	223	}
	224	module_exit(edsa_cleanup_module);