[mirror_ubuntu-artful-kernel.git] / net / dsa / tag_dsa.c

/*
 * net/dsa/tag_dsa.c - (Non-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

static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct dsa_slave_priv *p = netdev_priv(dev);
	u8 *dsa_header;

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

		/*
		 * Construct tagged FROM_CPU DSA tag from 802.1q tag.
		 */
		dsa_header = skb->data + 2 * ETH_ALEN;
		dsa_header[0] = 0x60 | p->parent->index;
		dsa_header[1] = p->port << 3;

		/*
		 * Move CFI field from byte 2 to byte 1.
		 */
		if (dsa_header[2] & 0x10) {
			dsa_header[1] |= 0x01;
			dsa_header[2] &= ~0x10;
		}
	} else {
		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 untagged FROM_CPU DSA tag.
		 */
		dsa_header = skb->data + 2 * ETH_ALEN;
		dsa_header[0] = 0x40 | p->parent->index;
		dsa_header[1] = p->port << 3;
		dsa_header[2] = 0x00;
		dsa_header[3] = 0x00;
	}

	return skb;

out_free:
	kfree_skb(skb);
	return NULL;
}

static int dsa_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 *dsa_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, DSA_HLEN)))
		goto out_drop;

	/*
	 * The ethertype field is part of the DSA header.
	 */
	dsa_header = skb->data - 2;

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

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

	/*
	 * Check that the source device exists and that the source
	 * port is a registered DSA port.
	 */
	if (source_device >= DSA_MAX_SWITCHES)
		goto out_drop;

	ds = dst->ds[source_device];
	if (!ds)
		goto out_drop;

	if (source_port >= DSA_MAX_PORTS || !ds->ports[source_port].netdev)
		goto out_drop;

	/*
	 * Convert the DSA header to an 802.1q header if the 'tagged'
	 * bit in the DSA header is set.  If the 'tagged' bit is clear,
	 * delete the DSA header entirely.
	 */
	if (dsa_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] = dsa_header[2] & ~0x10;
		new_header[3] = dsa_header[3];

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

		/*
		 * 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(dsa_header + 2, 2, 0));
			skb->csum = c;
		}

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

	skb->dev = ds->ports[source_port].netdev;
	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 dsa_netdev_ops = {
	.xmit	= dsa_xmit,
	.rcv	= dsa_rcv,
};
Commit	Line	Data
cf85d08f LB	1	/*
cf85d08f LB	2	* net/dsa/tag_dsa.c - (Non-ethertype) DSA tagging
e84665c9	3	* Copyright (c) 2008-2009 Marvell Semiconductor
cf85d08f 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>
cf85d08f LB	14	#include "dsa_priv.h"
	15
	16	#define DSA_HLEN 4
	17
4ed70ce9	18	static struct sk_buff dsa_xmit(struct sk_buff skb, struct net_device *dev)
cf85d08f LB	19	{
	20	struct dsa_slave_priv *p = netdev_priv(dev);
	21	u8 *dsa_header;
	22
cf85d08f LB	23	/*
	24	* Convert the outermost 802.1q tag to a DSA tag for tagged
	25	* packets, or insert a DSA tag between the addresses and
	26	* the ethertype field for untagged packets.
	27	*/
	28	if (skb->protocol == htons(ETH_P_8021Q)) {
	29	if (skb_cow_head(skb, 0) < 0)
	30	goto out_free;
	31
	32	/*
	33	* Construct tagged FROM_CPU DSA tag from 802.1q tag.
	34	*/
	35	dsa_header = skb->data + 2 * ETH_ALEN;
e84665c9	36	dsa_header[0] = 0x60 \| p->parent->index;
cf85d08f LB	37	dsa_header[1] = p->port << 3;
	38
	39	/*
	40	* Move CFI field from byte 2 to byte 1.
	41	*/
	42	if (dsa_header[2] & 0x10) {
	43	dsa_header[1] \|= 0x01;
	44	dsa_header[2] &= ~0x10;
	45	}
	46	} else {
	47	if (skb_cow_head(skb, DSA_HLEN) < 0)
	48	goto out_free;
	49	skb_push(skb, DSA_HLEN);
	50
	51	memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN);
	52
	53	/*
	54	* Construct untagged FROM_CPU DSA tag.
	55	*/
	56	dsa_header = skb->data + 2 * ETH_ALEN;
e84665c9	57	dsa_header[0] = 0x40 \| p->parent->index;
cf85d08f LB	58	dsa_header[1] = p->port << 3;
	59	dsa_header[2] = 0x00;
	60	dsa_header[3] = 0x00;
	61	}
	62
4ed70ce9	63	return skb;
cf85d08f LB	64
	65	out_free:
	66	kfree_skb(skb);
4ed70ce9	67	return NULL;
cf85d08f LB	68	}
	69
	70	static int dsa_rcv(struct sk_buff skb, struct net_device dev,
	71	struct packet_type pt, struct net_device orig_dev)
	72	{
e84665c9 LB	73	struct dsa_switch_tree *dst = dev->dsa_ptr;
e84665c9 LB	74	struct dsa_switch *ds;
cf85d08f	75	u8 *dsa_header;
e84665c9	76	int source_device;
cf85d08f LB	77	int source_port;
cf85d08f LB	78
e84665c9	79	if (unlikely(dst == NULL))
cf85d08f LB	80	goto out_drop;
	81
	82	skb = skb_unshare(skb, GFP_ATOMIC);
	83	if (skb == NULL)
	84	goto out;
	85
	86	if (unlikely(!pskb_may_pull(skb, DSA_HLEN)))
	87	goto out_drop;
	88
	89	/*
	90	* The ethertype field is part of the DSA header.
	91	*/
	92	dsa_header = skb->data - 2;
	93
	94	/*
e84665c9	95	* Check that frame type is either TO_CPU or FORWARD.
cf85d08f	96	*/
e84665c9	97	if ((dsa_header[0] & 0xc0) != 0x00 && (dsa_header[0] & 0xc0) != 0xc0)
cf85d08f LB	98	goto out_drop;
	99
	100	/*
e84665c9	101	* Determine source device and port.
cf85d08f	102	*/
e84665c9	103	source_device = dsa_header[0] & 0x1f;
cf85d08f	104	source_port = (dsa_header[1] >> 3) & 0x1f;
e84665c9 LB	105
	106	/*
	107	* Check that the source device exists and that the source
	108	* port is a registered DSA port.
	109	*/
149cafd7	110	if (source_device >= DSA_MAX_SWITCHES)
e84665c9	111	goto out_drop;
149cafd7	112
e84665c9	113	ds = dst->ds[source_device];
149cafd7 AL	114	if (!ds)
	115	goto out_drop;
	116
c8b09808	117	if (source_port >= DSA_MAX_PORTS \|\| !ds->ports[source_port].netdev)
cf85d08f LB	118	goto out_drop;
	119
	120	/*
	121	* Convert the DSA header to an 802.1q header if the 'tagged'
	122	* bit in the DSA header is set. If the 'tagged' bit is clear,
	123	* delete the DSA header entirely.
	124	*/
	125	if (dsa_header[0] & 0x20) {
	126	u8 new_header[4];
	127
	128	/*
	129	* Insert 802.1q ethertype and copy the VLAN-related
	130	* fields, but clear the bit that will hold CFI (since
	131	* DSA uses that bit location for another purpose).
	132	*/
	133	new_header[0] = (ETH_P_8021Q >> 8) & 0xff;
	134	new_header[1] = ETH_P_8021Q & 0xff;
	135	new_header[2] = dsa_header[2] & ~0x10;
	136	new_header[3] = dsa_header[3];
	137
	138	/*
	139	* Move CFI bit from its place in the DSA header to
	140	* its 802.1q-designated place.
	141	*/
	142	if (dsa_header[1] & 0x01)
	143	new_header[2] \|= 0x10;
	144
	145	/*
	146	* Update packet checksum if skb is CHECKSUM_COMPLETE.
	147	*/
	148	if (skb->ip_summed == CHECKSUM_COMPLETE) {
	149	__wsum c = skb->csum;
	150	c = csum_add(c, csum_partial(new_header + 2, 2, 0));
	151	c = csum_sub(c, csum_partial(dsa_header + 2, 2, 0));
	152	skb->csum = c;
	153	}
	154
	155	memcpy(dsa_header, new_header, DSA_HLEN);
	156	} else {
	157	/*
	158	* Remove DSA tag and update checksum.
	159	*/
	160	skb_pull_rcsum(skb, DSA_HLEN);
	161	memmove(skb->data - ETH_HLEN,
	162	skb->data - ETH_HLEN - DSA_HLEN,
	163	2 * ETH_ALEN);
	164	}
	165
c8b09808	166	skb->dev = ds->ports[source_port].netdev;
cf85d08f	167	skb_push(skb, ETH_HLEN);
14ee6742	168	skb->pkt_type = PACKET_HOST;
cf85d08f LB	169	skb->protocol = eth_type_trans(skb, skb->dev);
cf85d08f LB	170
cf85d08f LB	171	skb->dev->stats.rx_packets++;
	172	skb->dev->stats.rx_bytes += skb->len;
	173
	174	netif_receive_skb(skb);
	175
	176	return 0;
	177
	178	out_drop:
	179	kfree_skb(skb);
	180	out:
	181	return 0;
	182	}
	183
3e8a72d1 FF	184	const struct dsa_device_ops dsa_netdev_ops = {
	185	.xmit = dsa_xmit,
	186	.rcv = dsa_rcv,
cf85d08f	187	};