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Merge branch 'dsa-tagger-helpers'

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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: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2021-08-11 14:44:59 +01:00
commit 88be326349
8 changed files with 119 additions and 81 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

78
net/dsa/dsa_priv.h
View File

@ -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);

16
net/dsa/tag_brcm.c
View File

@ -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;
}

20
net/dsa/tag_dsa.c
View File

@ -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;

18
net/dsa/tag_lan9303.c
View File

@ -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);

14
net/dsa/tag_mtk.c
View File

@ -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);

13
net/dsa/tag_qca.c
View File

@ -36,8 +36,8 @@ static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev)
skb_push(skb, QCA_HDR_LEN);
memmove(skb->data, skb->data + QCA_HDR_LEN, 2 * ETH_ALEN);
phdr = (__be16 *)(skb->data + 2 * ETH_ALEN);
dsa_alloc_etype_header(skb, QCA_HDR_LEN);
phdr = dsa_etype_header_pos_tx(skb);
/* Set the version field, and set destination port information */
hdr = QCA_HDR_VERSION << QCA_HDR_XMIT_VERSION_S |
@ -58,11 +58,7 @@ static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev)
if (unlikely(!pskb_may_pull(skb, QCA_HDR_LEN)))
return NULL;
/* The QCA header is added by the switch between src addr and Ethertype
* At this point, skb->data points to ethertype so header should be
* right before
*/
phdr = (__be16 *)(skb->data - 2);
phdr = dsa_etype_header_pos_rx(skb);
hdr = ntohs(*phdr);
/* Make sure the version is correct */
@ -72,8 +68,7 @@ static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev)
/* Remove QCA tag and recalculate checksum */
skb_pull_rcsum(skb, QCA_HDR_LEN);
memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - QCA_HDR_LEN,
ETH_HLEN - QCA_HDR_LEN);
dsa_strip_etype_header(skb, QCA_HDR_LEN);
/* Get source port information */
port = (hdr & QCA_HDR_RECV_SOURCE_PORT_MASK);

16
net/dsa/tag_rtl4_a.c
View File

@ -47,8 +47,8 @@ static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb,
dp->index);
skb_push(skb, RTL4_A_HDR_LEN);
memmove(skb->data, skb->data + RTL4_A_HDR_LEN, 2 * ETH_ALEN);
tag = skb->data + 2 * ETH_ALEN;
dsa_alloc_etype_header(skb, RTL4_A_HDR_LEN);
tag = dsa_etype_header_pos_tx(skb);
/* Set Ethertype */
p = (__be16 *)tag;
@ -76,12 +76,7 @@ static struct sk_buff *rtl4a_tag_rcv(struct sk_buff *skb,
if (unlikely(!pskb_may_pull(skb, RTL4_A_HDR_LEN)))
return NULL;
/* The RTL4 header has its own custom Ethertype 0x8899 and that
* starts right at the beginning of the packet, after the src
* ethernet addr. Apparently skb->data always points 2 bytes in,
* behind the Ethertype.
*/
tag = skb->data - 2;
tag = dsa_etype_header_pos_rx(skb);
p = (__be16 *)tag;
etype = ntohs(*p);
if (etype != RTL4_A_ETHERTYPE) {
@ -108,10 +103,7 @@ static struct sk_buff *rtl4a_tag_rcv(struct sk_buff *skb,
/* Remove RTL4 tag and recalculate checksum */
skb_pull_rcsum(skb, RTL4_A_HDR_LEN);
/* Move ethernet DA and SA in front of the data */
memmove(skb->data - ETH_HLEN,
skb->data - ETH_HLEN - RTL4_A_HDR_LEN,
2 * ETH_ALEN);
dsa_strip_etype_header(skb, RTL4_A_HDR_LEN);
dsa_default_offload_fwd_mark(skb);

25
net/dsa/tag_sja1105.c
View File

@ -188,7 +188,6 @@ static struct sk_buff *sja1110_xmit(struct sk_buff *skb,
u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index);
u16 queue_mapping = skb_get_queue_mapping(skb);
u8 pcp = netdev_txq_to_tc(netdev, queue_mapping);
struct ethhdr *eth_hdr;
__be32 *tx_trailer;
__be16 *tx_header;
int trailer_pos;
@ -206,28 +205,24 @@ static struct sk_buff *sja1110_xmit(struct sk_buff *skb,
skb_push(skb, SJA1110_HEADER_LEN);
/* Move Ethernet header to the left, making space for DSA tag */
memmove(skb->data, skb->data + SJA1110_HEADER_LEN, 2 * ETH_ALEN);
dsa_alloc_etype_header(skb, SJA1110_HEADER_LEN);
trailer_pos = skb->len;
/* On TX, skb->data points to skb_mac_header(skb) */
eth_hdr = (struct ethhdr *)skb->data;
tx_header = (__be16 *)(eth_hdr + 1);
tx_header = dsa_etype_header_pos_tx(skb);
tx_trailer = skb_put(skb, SJA1110_TX_TRAILER_LEN);
eth_hdr->h_proto = htons(ETH_P_SJA1110);
*tx_header = htons(SJA1110_HEADER_HOST_TO_SWITCH |
SJA1110_TX_HEADER_HAS_TRAILER |
SJA1110_TX_HEADER_TRAILER_POS(trailer_pos));
tx_header[0] = htons(ETH_P_SJA1110);
tx_header[1] = htons(SJA1110_HEADER_HOST_TO_SWITCH |
SJA1110_TX_HEADER_HAS_TRAILER |
SJA1110_TX_HEADER_TRAILER_POS(trailer_pos));
*tx_trailer = cpu_to_be32(SJA1110_TX_TRAILER_PRIO(pcp) |
SJA1110_TX_TRAILER_SWITCHID(dp->ds->index) |
SJA1110_TX_TRAILER_DESTPORTS(BIT(dp->index)));
if (clone) {
u8 ts_id = SJA1105_SKB_CB(clone)->ts_id;
*tx_header |= htons(SJA1110_TX_HEADER_TAKE_TS);
tx_header[1] |= htons(SJA1110_TX_HEADER_TAKE_TS);
*tx_trailer |= cpu_to_be32(SJA1110_TX_TRAILER_TSTAMP_ID(ts_id));
}
@ -443,11 +438,11 @@ static struct sk_buff *sja1105_rcv(struct sk_buff *skb,
static struct sk_buff *sja1110_rcv_meta(struct sk_buff *skb, u16 rx_header)
{
u8 *buf = dsa_etype_header_pos_rx(skb) + SJA1110_HEADER_LEN;
int switch_id = SJA1110_RX_HEADER_SWITCH_ID(rx_header);
int n_ts = SJA1110_RX_HEADER_N_TS(rx_header);
struct net_device *master = skb->dev;
struct dsa_port *cpu_dp;
u8 *buf = skb->data + 2;
struct dsa_switch *ds;
int i;
@ -532,9 +527,7 @@ static struct sk_buff *sja1110_rcv_inband_control_extension(struct sk_buff *skb,
/* Advance skb->data past the DSA header */
skb_pull_rcsum(skb, SJA1110_HEADER_LEN);
/* Remove the DSA header */
memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - SJA1110_HEADER_LEN,
2 * ETH_ALEN);
dsa_strip_etype_header(skb, SJA1110_HEADER_LEN);
/* With skb->data in its final place, update the MAC header
* so that eth_hdr() continues to works properly.