Commit 88be3263 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'dsa-tagger-helpers' 



Vladimir Oltean says:

====================
DSA tagger helpers

The goal of this series is to minimize the use of memmove and skb->data
in the DSA tagging protocol drivers. Unfiltered access to this level of
information is not very friendly to drive-by contributors, and sometimes
is also not the easiest to review.

For starters, I have converted the most common form of DSA tagging
protocols: the DSA headers which are placed where the EtherType is.

The helper functions introduced by this series are:
- dsa_alloc_etype_header
- dsa_strip_etype_header
- dsa_etype_header_pos_rx
- dsa_etype_header_pos_tx

This series is just a resend as non-RFC of v1.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 1a8e628c a72808b6

net/dsa/dsa_priv.h

+78 −0
Original line number Diff line number Diff line
@@ -452,6 +452,84 @@ static inline void dsa_default_offload_fwd_mark(struct sk_buff *skb) 
	skb->offload_fwd_mark = !!(dp->bridge_dev);

}



/* Helper for removing DSA header tags from packets in the RX path.

 * Must not be called before skb_pull(len).

 *                                                                 skb->data

 *                                                                         |

 *                                                                         v

 * |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |

 * +-----------------------+-----------------------+---------------+-------+

 * |    Destination MAC    |      Source MAC       |  DSA header   | EType |

 * +-----------------------+-----------------------+---------------+-------+

 *                                                 |               |

 * <----- len ----->                               <----- len ----->

 *                 |

 *       >>>>>>>   v

 *       >>>>>>>   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |

 *       >>>>>>>   +-----------------------+-----------------------+-------+

 *       >>>>>>>   |    Destination MAC    |      Source MAC       | EType |

 *                 +-----------------------+-----------------------+-------+

 *                                                                         ^

 *                                                                         |

 *                                                                 skb->data

 */

static inline void dsa_strip_etype_header(struct sk_buff *skb, int len)

{

	memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - len, 2 * ETH_ALEN);

}



/* Helper for creating space for DSA header tags in TX path packets.

 * Must not be called before skb_push(len).

 *

 * Before:

 *

 *       <<<<<<<   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |

 * ^     <<<<<<<   +-----------------------+-----------------------+-------+

 * |     <<<<<<<   |    Destination MAC    |      Source MAC       | EType |

 * |               +-----------------------+-----------------------+-------+

 * <----- len ----->

 * |

 * |

 * skb->data

 *

 * After:

 *

 * |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |

 * +-----------------------+-----------------------+---------------+-------+

 * |    Destination MAC    |      Source MAC       |  DSA header   | EType |

 * +-----------------------+-----------------------+---------------+-------+

 * ^                                               |               |

 * |                                               <----- len ----->

 * skb->data

 */

static inline void dsa_alloc_etype_header(struct sk_buff *skb, int len)

{

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

}



/* On RX, eth_type_trans() on the DSA master pulls ETH_HLEN bytes starting from

 * skb_mac_header(skb), which leaves skb->data pointing at the first byte after

 * what the DSA master perceives as the EtherType (the beginning of the L3

 * protocol). Since DSA EtherType header taggers treat the EtherType as part of

 * the DSA tag itself, and the EtherType is 2 bytes in length, the DSA header

 * is located 2 bytes behind skb->data. Note that EtherType in this context

 * means the first 2 bytes of the DSA header, not the encapsulated EtherType

 * that will become visible after the DSA header is stripped.

 */

static inline void *dsa_etype_header_pos_rx(struct sk_buff *skb)

{

	return skb->data - 2;

}



/* On TX, skb->data points to skb_mac_header(skb), which means that EtherType

 * header taggers start exactly where the EtherType is (the EtherType is

 * treated as part of the DSA header).

 */

static inline void *dsa_etype_header_pos_tx(struct sk_buff *skb)

{

	return skb->data + 2 * ETH_ALEN;

}



/* switch.c */

int dsa_switch_register_notifier(struct dsa_switch *ds);

void dsa_switch_unregister_notifier(struct dsa_switch *ds);

net/dsa/tag_brcm.c

+5 −11
Original line number Diff line number Diff line
@@ -99,7 +99,7 @@ static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb, 
	skb_push(skb, BRCM_TAG_LEN);



	if (offset)

		memmove(skb->data, skb->data + BRCM_TAG_LEN, offset);

		dsa_alloc_etype_header(skb, BRCM_TAG_LEN);



	brcm_tag = skb->data + offset;
@@ -190,10 +190,7 @@ static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev) 
	if (!nskb)

		return nskb;



	/* Move the Ethernet DA and SA */

	memmove(nskb->data - ETH_HLEN,

		nskb->data - ETH_HLEN - BRCM_TAG_LEN,

		2 * ETH_ALEN);

	dsa_strip_etype_header(skb, BRCM_TAG_LEN);



	return nskb;

}
@@ -231,7 +228,7 @@ static struct sk_buff *brcm_leg_tag_xmit(struct sk_buff *skb, 


	skb_push(skb, BRCM_LEG_TAG_LEN);



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

	dsa_alloc_etype_header(skb, BRCM_LEG_TAG_LEN);



	brcm_tag = skb->data + 2 * ETH_ALEN;
@@ -257,7 +254,7 @@ static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb, 
	if (unlikely(!pskb_may_pull(skb, BRCM_LEG_PORT_ID)))

		return NULL;



	brcm_tag = skb->data - 2;

	brcm_tag = dsa_etype_header_pos_rx(skb);



	source_port = brcm_tag[5] & BRCM_LEG_PORT_ID;
@@ -270,10 +267,7 @@ static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb, 


	dsa_default_offload_fwd_mark(skb);



	/* Move the Ethernet DA and SA */

	memmove(skb->data - ETH_HLEN,

		skb->data - ETH_HLEN - BRCM_LEG_TAG_LEN,

		2 * ETH_ALEN);

	dsa_strip_etype_header(skb, BRCM_LEG_TAG_LEN);



	return skb;

}

net/dsa/tag_dsa.c

+8 −12
Original line number Diff line number Diff line
@@ -166,11 +166,11 @@ static struct sk_buff *dsa_xmit_ll(struct sk_buff *skb, struct net_device *dev, 
	if (skb->protocol == htons(ETH_P_8021Q)) {

		if (extra) {

			skb_push(skb, extra);

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

			dsa_alloc_etype_header(skb, extra);

		}



		/* Construct tagged DSA tag from 802.1Q tag. */

		dsa_header = skb->data + 2 * ETH_ALEN + extra;

		dsa_header = dsa_etype_header_pos_tx(skb) + extra;

		dsa_header[0] = (cmd << 6) | 0x20 | tag_dev;

		dsa_header[1] = tag_port << 3;
@@ -181,10 +181,10 @@ static struct sk_buff *dsa_xmit_ll(struct sk_buff *skb, struct net_device *dev, 
		}

	} else {

		skb_push(skb, DSA_HLEN + extra);

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

		dsa_alloc_etype_header(skb, DSA_HLEN + extra);



		/* Construct untagged DSA tag. */

		dsa_header = skb->data + 2 * ETH_ALEN + extra;

		dsa_header = dsa_etype_header_pos_tx(skb) + extra;



		dsa_header[0] = (cmd << 6) | tag_dev;

		dsa_header[1] = tag_port << 3;
@@ -205,7 +205,7 @@ static struct sk_buff *dsa_rcv_ll(struct sk_buff *skb, struct net_device *dev, 
	u8 *dsa_header;



	/* The ethertype field is part of the DSA header. */

	dsa_header = skb->data - 2;

	dsa_header = dsa_etype_header_pos_rx(skb);



	cmd = dsa_header[0] >> 6;

	switch (cmd) {
@@ -312,14 +312,10 @@ static struct sk_buff *dsa_rcv_ll(struct sk_buff *skb, struct net_device *dev, 
		memcpy(dsa_header, new_header, DSA_HLEN);



		if (extra)

			memmove(skb->data - ETH_HLEN,

				skb->data - ETH_HLEN - extra,

				2 * ETH_ALEN);

			dsa_strip_etype_header(skb, extra);

	} else {

		skb_pull_rcsum(skb, DSA_HLEN);

		memmove(skb->data - ETH_HLEN,

			skb->data - ETH_HLEN - DSA_HLEN - extra,

			2 * ETH_ALEN);

		dsa_strip_etype_header(skb, DSA_HLEN + extra);

	}



	return skb;
@@ -364,7 +360,7 @@ static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev) 
	if (!skb)

		return NULL;



	edsa_header = skb->data + 2 * ETH_ALEN;

	edsa_header = dsa_etype_header_pos_tx(skb);

	edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff;

	edsa_header[1] = ETH_P_EDSA & 0xff;

	edsa_header[2] = 0x00;

net/dsa/tag_lan9303.c

+7 −11
Original line number Diff line number Diff line
@@ -62,9 +62,10 @@ static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev) 
	skb_push(skb, LAN9303_TAG_LEN);



	/* make room between MACs and Ether-Type */

	memmove(skb->data, skb->data + LAN9303_TAG_LEN, 2 * ETH_ALEN);

	dsa_alloc_etype_header(skb, LAN9303_TAG_LEN);



	lan9303_tag = dsa_etype_header_pos_tx(skb);



	lan9303_tag = (__be16 *)(skb->data + 2 * ETH_ALEN);

	tag = lan9303_xmit_use_arl(dp, skb->data) ?

		LAN9303_TAG_TX_USE_ALR :

		dp->index | LAN9303_TAG_TX_STP_OVERRIDE;
@@ -86,13 +87,7 @@ static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev) 
		return NULL;

	}



	/* '->data' points into the middle of our special VLAN tag information:

	 *

	 * ~ MAC src   | 0x81 | 0x00 | 0xyy | 0xzz | ether type

	 *                           ^

	 *                        ->data

	 */

	lan9303_tag = (__be16 *)(skb->data - 2);

	lan9303_tag = dsa_etype_header_pos_rx(skb);



	if (lan9303_tag[0] != htons(ETH_P_8021Q)) {

		dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid VLAN marker\n");
@@ -112,8 +107,9 @@ static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev) 
	 * and the current ethertype field.

	 */

	skb_pull_rcsum(skb, 2 + 2);

	memmove(skb->data - ETH_HLEN, skb->data - (ETH_HLEN + LAN9303_TAG_LEN),

		2 * ETH_ALEN);



	dsa_strip_etype_header(skb, LAN9303_TAG_LEN);



	if (!(lan9303_tag1 & LAN9303_TAG_RX_TRAPPED_TO_CPU))

		dsa_default_offload_fwd_mark(skb);

net/dsa/tag_mtk.c

+4 −10
Original line number Diff line number Diff line
@@ -41,10 +41,10 @@ static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb, 
	default:

		xmit_tpid = MTK_HDR_XMIT_UNTAGGED;

		skb_push(skb, MTK_HDR_LEN);

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

		dsa_alloc_etype_header(skb, MTK_HDR_LEN);

	}



	mtk_tag = skb->data + 2 * ETH_ALEN;

	mtk_tag = dsa_etype_header_pos_tx(skb);



	/* Mark tag attribute on special tag insertion to notify hardware

	 * whether that's a combined special tag with 802.1Q header.
@@ -70,19 +70,13 @@ static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev) 
	if (unlikely(!pskb_may_pull(skb, MTK_HDR_LEN)))

		return NULL;



	/* The MTK header is added by the switch between src addr

	 * and ethertype at this point, skb->data points to 2 bytes

	 * after src addr so header should be 2 bytes right before.

	 */

	phdr = (__be16 *)(skb->data - 2);

	phdr = dsa_etype_header_pos_rx(skb);

	hdr = ntohs(*phdr);



	/* Remove MTK tag and recalculate checksum. */

	skb_pull_rcsum(skb, MTK_HDR_LEN);



	memmove(skb->data - ETH_HLEN,

		skb->data - ETH_HLEN - MTK_HDR_LEN,

		2 * ETH_ALEN);

	dsa_strip_etype_header(skb, MTK_HDR_LEN);



	/* Get source port information */

	port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK);