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Merge branch 'net-dsa-tag_dsa-unify-regular-and-ethertype-dsa-taggers'

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Tobias Waldekranz says:

====================
net: dsa: tag_dsa: Unify regular and ethertype DSA taggers

The first patch ports tag_edsa.c's handling of IGMP/MLD traps to
tag_dsa.c. That way, we start from two logically equivalent taggers
that are then merged. The second commit does the heavy lifting of
actually fusing tag_dsa.c and tag_edsa.c. The final one just follows
up with some clean up of existing comments.

v2 -> v3:
  - Add the first patch described above as suggested by Andrew.
  - Better documentation of TO_SNIFFER and FORWARD tags.
  - Spelling.

v1 -> v2:
  - Fixed some grammar and whitespace errors.
  - Removed unnecessary default value in Kconfig.
  - Removed unnecessary #ifdef.
  - Split out comment fixes from functional changes.
  - Fully document enum dsa_code.
====================

Link: https://lore.kernel.org/r/20201114234558.31203-1-tobias@waldekranz.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Jakub Kicinski 2020-11-17 09:16:13 -08:00
commit f85cd064cd
4 changed files with 272 additions and 269 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
net/dsa/Kconfig
View File

@ -68,14 +68,19 @@ config NET_DSA_TAG_GSWIP
Say Y or M if you want to enable support for tagging frames for the
Lantiq / Intel GSWIP switches.
config NET_DSA_TAG_DSA_COMMON
tristate
config NET_DSA_TAG_DSA
tristate "Tag driver for Marvell switches using DSA headers"
select NET_DSA_TAG_DSA_COMMON
help
Say Y or M if you want to enable support for tagging frames for the
Marvell switches which use DSA headers.
config NET_DSA_TAG_EDSA
tristate "Tag driver for Marvell switches using EtherType DSA headers"
select NET_DSA_TAG_DSA_COMMON
help
Say Y or M if you want to enable support for tagging frames for the
Marvell switches which use EtherType DSA headers.

3
net/dsa/Makefile
View File

@ -7,8 +7,7 @@ dsa_core-y += dsa.o dsa2.o master.o port.o slave.o switch.o
obj-$(CONFIG_NET_DSA_TAG_8021Q) += tag_8021q.o
obj-$(CONFIG_NET_DSA_TAG_AR9331) += tag_ar9331.o
obj-$(CONFIG_NET_DSA_TAG_BRCM_COMMON) += tag_brcm.o
obj-$(CONFIG_NET_DSA_TAG_DSA) += tag_dsa.o
obj-$(CONFIG_NET_DSA_TAG_EDSA) += tag_edsa.o
obj-$(CONFIG_NET_DSA_TAG_DSA_COMMON) += tag_dsa.o
obj-$(CONFIG_NET_DSA_TAG_GSWIP) += tag_gswip.o
obj-$(CONFIG_NET_DSA_TAG_HELLCREEK) += tag_hellcreek.o
obj-$(CONFIG_NET_DSA_TAG_KSZ) += tag_ksz.o

331
net/dsa/tag_dsa.c
View File

@ -1,7 +1,48 @@
// SPDX-License-Identifier: GPL-2.0+
/*
* net/dsa/tag_dsa.c - (Non-ethertype) DSA tagging
* Regular and Ethertype DSA tagging
* Copyright (c) 2008-2009 Marvell Semiconductor
*
* Regular DSA
* -----------
* For untagged (in 802.1Q terms) packets, the switch will splice in
* the tag between the SA and the ethertype of the original
* packet. Tagged frames will instead have their outermost .1Q tag
* converted to a DSA tag. It expects the same layout when receiving
* packets from the CPU.
*
* Example:
*
* .----.----.----.---------
* Pu: | DA | SA | ET | Payload ...
* '----'----'----'---------
* 6 6 2 N
* .----.----.--------.-----.----.---------
* Pt: | DA | SA | 0x8100 | TCI | ET | Payload ...
* '----'----'--------'-----'----'---------
* 6 6 2 2 2 N
* .----.----.-----.----.---------
* Pd: | DA | SA | DSA | ET | Payload ...
* '----'----'-----'----'---------
* 6 6 4 2 N
*
* No matter if a packet is received untagged (Pu) or tagged (Pt),
* they will both have the same layout (Pd) when they are sent to the
* CPU. This is done by ignoring 802.3, replacing the ethertype field
* with more metadata, among which is a bit to signal if the original
* packet was tagged or not.
*
* Ethertype DSA
* -------------
* Uses the exact same tag format as regular DSA, but also includes a
* proper ethertype field (which the mv88e6xxx driver sets to
* ETH_P_EDSA/0xdada) followed by two zero bytes:
*
* .----.----.--------.--------.-----.----.---------
* | DA | SA | 0xdada | 0x0000 | DSA | ET | Payload ...
* '----'----'--------'--------'-----'----'---------
* 6 6 2 2 4 2 N
*/
#include <linux/etherdevice.h>
@ -12,41 +53,104 @@
#define DSA_HLEN 4
static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev)
/**
* enum dsa_cmd - DSA Command
* @DSA_CMD_TO_CPU: Set on packets that were trapped or mirrored to
* the CPU port. This is needed to implement control protocols,
* e.g. STP and LLDP, that must not allow those control packets to
* be switched according to the normal rules.
* @DSA_CMD_FROM_CPU: Used by the CPU to send a packet to a specific
* port, ignoring all the barriers that the switch normally
* enforces (VLANs, STP port states etc.). No source address
* learning takes place. "sudo send packet"
* @DSA_CMD_TO_SNIFFER: Set on the copies of packets that matched some
* user configured ingress or egress monitor criteria. These are
* forwarded by the switch tree to the user configured ingress or
* egress monitor port, which can be set to the CPU port or a
* regular port. If the destination is a regular port, the tag
* will be removed before egressing the port. If the destination
* is the CPU port, the tag will not be removed.
* @DSA_CMD_FORWARD: This tag is used on all bulk traffic passing
* through the switch tree, including the flows that are directed
* towards the CPU. Its device/port tuple encodes the original
* source port on which the packet ingressed. It can also be used
* on transmit by the CPU to defer the forwarding decision to the
* hardware, based on the current config of PVT/VTU/ATU
* etc. Source address learning takes places if enabled on the
* receiving DSA/CPU port.
*/
enum dsa_cmd {
DSA_CMD_TO_CPU = 0,
DSA_CMD_FROM_CPU = 1,
DSA_CMD_TO_SNIFFER = 2,
DSA_CMD_FORWARD = 3
};
/**
* enum dsa_code - TO_CPU Code
*
* @DSA_CODE_MGMT_TRAP: DA was classified as a management
* address. Typical examples include STP BPDUs and LLDP.
* @DSA_CODE_FRAME2REG: Response to a "remote management" request.
* @DSA_CODE_IGMP_MLD_TRAP: IGMP/MLD signaling.
* @DSA_CODE_POLICY_TRAP: Frame matched some policy configuration on
* the device. Typical examples are matching on DA/SA/VID and DHCP
* snooping.
* @DSA_CODE_ARP_MIRROR: The name says it all really.
* @DSA_CODE_POLICY_MIRROR: Same as @DSA_CODE_POLICY_TRAP, but the
* particular policy was set to trigger a mirror instead of a
* trap.
* @DSA_CODE_RESERVED_6: Unused on all devices up to at least 6393X.
* @DSA_CODE_RESERVED_7: Unused on all devices up to at least 6393X.
*
* A 3-bit code is used to relay why a particular frame was sent to
* the CPU. We only use this to determine if the packet was mirrored
* or trapped, i.e. whether the packet has been forwarded by hardware
* or not.
*
* This is the superset of all possible codes. Any particular device
* may only implement a subset.
*/
enum dsa_code {
DSA_CODE_MGMT_TRAP = 0,
DSA_CODE_FRAME2REG = 1,
DSA_CODE_IGMP_MLD_TRAP = 2,
DSA_CODE_POLICY_TRAP = 3,
DSA_CODE_ARP_MIRROR = 4,
DSA_CODE_POLICY_MIRROR = 5,
DSA_CODE_RESERVED_6 = 6,
DSA_CODE_RESERVED_7 = 7
};
static struct sk_buff *dsa_xmit_ll(struct sk_buff *skb, struct net_device *dev,
u8 extra)
{
struct dsa_port *dp = dsa_slave_to_port(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)) {
/*
* Construct tagged FROM_CPU DSA tag from 802.1q tag.
*/
dsa_header = skb->data + 2 * ETH_ALEN;
dsa_header[0] = 0x60 | dp->ds->index;
if (extra) {
skb_push(skb, extra);
memmove(skb->data, skb->data + extra, 2 * ETH_ALEN);
}
/* Construct tagged FROM_CPU DSA tag from 802.1Q tag. */
dsa_header = skb->data + 2 * ETH_ALEN + extra;
dsa_header[0] = (DSA_CMD_FROM_CPU << 6) | 0x20 | dp->ds->index;
dsa_header[1] = dp->index << 3;
/*
* Move CFI field from byte 2 to byte 1.
*/
/* Move CFI field from byte 2 to byte 1. */
if (dsa_header[2] & 0x10) {
dsa_header[1] |= 0x01;
dsa_header[2] &= ~0x10;
}
} else {
skb_push(skb, DSA_HLEN);
skb_push(skb, DSA_HLEN + extra);
memmove(skb->data, skb->data + DSA_HLEN + extra, 2 * ETH_ALEN);
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 | dp->ds->index;
/* Construct untagged FROM_CPU DSA tag. */
dsa_header = skb->data + 2 * ETH_ALEN + extra;
dsa_header[0] = (DSA_CMD_FROM_CPU << 6) | dp->ds->index;
dsa_header[1] = dp->index << 3;
dsa_header[2] = 0x00;
dsa_header[3] = 0x00;
@ -55,30 +159,60 @@ static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev)
return skb;
}
static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt)
static struct sk_buff *dsa_rcv_ll(struct sk_buff *skb, struct net_device *dev,
u8 extra)
{
int source_device, source_port;
enum dsa_code code;
enum dsa_cmd cmd;
u8 *dsa_header;
int source_device;
int source_port;
if (unlikely(!pskb_may_pull(skb, DSA_HLEN)))
return NULL;
/*
* The ethertype field is part of the DSA header.
*/
/* 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)
return NULL;
cmd = dsa_header[0] >> 6;
switch (cmd) {
case DSA_CMD_FORWARD:
skb->offload_fwd_mark = 1;
break;
case DSA_CMD_TO_CPU:
code = (dsa_header[1] & 0x6) | ((dsa_header[2] >> 4) & 1);
switch (code) {
case DSA_CODE_FRAME2REG:
/* Remote management is not implemented yet,
* drop.
*/
return NULL;
case DSA_CODE_ARP_MIRROR:
case DSA_CODE_POLICY_MIRROR:
/* Mark mirrored packets to notify any upper
* device (like a bridge) that forwarding has
* already been done by hardware.
*/
skb->offload_fwd_mark = 1;
break;
case DSA_CODE_MGMT_TRAP:
case DSA_CODE_IGMP_MLD_TRAP:
case DSA_CODE_POLICY_TRAP:
/* Traps have, by definition, not been
* forwarded by hardware, so don't mark them.
*/
break;
default:
/* Reserved code, this could be anything. Drop
* seems like the safest option.
*/
return NULL;
}
break;
default:
return NULL;
}
/*
* Determine source device and port.
*/
source_device = dsa_header[0] & 0x1f;
source_port = (dsa_header[1] >> 3) & 0x1f;
@ -86,16 +220,15 @@ static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev,
if (!skb->dev)
return NULL;
/*
* 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 the 'tagged' bit is set; convert the DSA tag to a 802.1Q
* tag, and delete the ethertype (extra) if applicable. If the
* 'tagged' bit is cleared; delete the DSA tag, and ethertype
* if applicable.
*/
if (dsa_header[0] & 0x20) {
u8 new_header[4];
/*
* Insert 802.1q ethertype and copy the VLAN-related
/* 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).
*/
@ -104,16 +237,13 @@ static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev,
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.
/* 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.
*/
/* 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));
@ -122,30 +252,101 @@ static struct sk_buff *dsa_rcv(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);
} else {
/*
* Remove DSA tag and update checksum.
*/
skb_pull_rcsum(skb, DSA_HLEN);
memmove(skb->data - ETH_HLEN,
skb->data - ETH_HLEN - DSA_HLEN,
skb->data - ETH_HLEN - DSA_HLEN - extra,
2 * ETH_ALEN);
}
skb->offload_fwd_mark = 1;
return skb;
}
#if IS_ENABLED(CONFIG_NET_DSA_TAG_DSA)
static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev)
{
return dsa_xmit_ll(skb, dev, 0);
}
static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt)
{
if (unlikely(!pskb_may_pull(skb, DSA_HLEN)))
return NULL;
return dsa_rcv_ll(skb, dev, 0);
}
static const struct dsa_device_ops dsa_netdev_ops = {
.name = "dsa",
.proto = DSA_TAG_PROTO_DSA,
.xmit = dsa_xmit,
.rcv = dsa_rcv,
.name = "dsa",
.proto = DSA_TAG_PROTO_DSA,
.xmit = dsa_xmit,
.rcv = dsa_rcv,
.overhead = DSA_HLEN,
};
MODULE_LICENSE("GPL");
DSA_TAG_DRIVER(dsa_netdev_ops);
MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_DSA);
#endif /* CONFIG_NET_DSA_TAG_DSA */
module_dsa_tag_driver(dsa_netdev_ops);
#if IS_ENABLED(CONFIG_NET_DSA_TAG_EDSA)
#define EDSA_HLEN 8
static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev)
{
u8 *edsa_header;
skb = dsa_xmit_ll(skb, dev, EDSA_HLEN - DSA_HLEN);
if (!skb)
return NULL;
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;
return skb;
}
static struct sk_buff *edsa_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt)
{
if (unlikely(!pskb_may_pull(skb, EDSA_HLEN)))
return NULL;
skb_pull_rcsum(skb, EDSA_HLEN - DSA_HLEN);
return dsa_rcv_ll(skb, dev, EDSA_HLEN - DSA_HLEN);
}
static const struct dsa_device_ops edsa_netdev_ops = {
.name = "edsa",
.proto = DSA_TAG_PROTO_EDSA,
.xmit = edsa_xmit,
.rcv = edsa_rcv,
.overhead = EDSA_HLEN,
};
DSA_TAG_DRIVER(edsa_netdev_ops);
MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_EDSA);
#endif /* CONFIG_NET_DSA_TAG_EDSA */
static struct dsa_tag_driver *dsa_tag_drivers[] = {
#if IS_ENABLED(CONFIG_NET_DSA_TAG_DSA)
&DSA_TAG_DRIVER_NAME(dsa_netdev_ops),
#endif
#if IS_ENABLED(CONFIG_NET_DSA_TAG_EDSA)
&DSA_TAG_DRIVER_NAME(edsa_netdev_ops),
#endif
};
module_dsa_tag_drivers(dsa_tag_drivers);
MODULE_LICENSE("GPL");

202
net/dsa/tag_edsa.c
View File

@ -1,202 +0,0 @@
// SPDX-License-Identifier: GPL-2.0+
/*
* net/dsa/tag_edsa.c - Ethertype DSA tagging
* Copyright (c) 2008-2009 Marvell Semiconductor
*/
#include <linux/etherdevice.h>
#include <linux/list.h>
#include <linux/slab.h>
#include "dsa_priv.h"
#define DSA_HLEN 4
#define EDSA_HLEN 8
#define FRAME_TYPE_TO_CPU 0x00
#define FRAME_TYPE_FORWARD 0x03
#define TO_CPU_CODE_MGMT_TRAP 0x00
#define TO_CPU_CODE_FRAME2REG 0x01
#define TO_CPU_CODE_IGMP_MLD_TRAP 0x02
#define TO_CPU_CODE_POLICY_TRAP 0x03
#define TO_CPU_CODE_ARP_MIRROR 0x04
#define TO_CPU_CODE_POLICY_MIRROR 0x05
static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct dsa_port *dp = dsa_slave_to_port(dev);
u8 *edsa_header;
/*
* 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)) {
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 | dp->ds->index;
edsa_header[5] = dp->index << 3;
/*
* Move CFI field from byte 6 to byte 5.
*/
if (edsa_header[6] & 0x10) {
edsa_header[5] |= 0x01;
edsa_header[6] &= ~0x10;
}
} else {
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 | dp->ds->index;
edsa_header[5] = dp->index << 3;
edsa_header[6] = 0x00;
edsa_header[7] = 0x00;
}
return skb;
}
static struct sk_buff *edsa_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt)
{
u8 *edsa_header;
int frame_type;
int code;
int source_device;
int source_port;
if (unlikely(!pskb_may_pull(skb, EDSA_HLEN)))
return NULL;
/*
* Skip the two null bytes after the ethertype.
*/
edsa_header = skb->data + 2;
/*
* Check that frame type is either TO_CPU or FORWARD.
*/
frame_type = edsa_header[0] >> 6;
switch (frame_type) {
case FRAME_TYPE_TO_CPU:
code = (edsa_header[1] & 0x6) | ((edsa_header[2] >> 4) & 1);
/*
* Mark the frame to never egress on any port of the same switch
* unless it's a trapped IGMP/MLD packet, in which case the
* bridge might want to forward it.
*/
if (code != TO_CPU_CODE_IGMP_MLD_TRAP)
skb->offload_fwd_mark = 1;
break;
case FRAME_TYPE_FORWARD:
skb->offload_fwd_mark = 1;
break;
default:
return NULL;
}
/*
* Determine source device and port.
*/
source_device = edsa_header[0] & 0x1f;
source_port = (edsa_header[1] >> 3) & 0x1f;
skb->dev = dsa_master_find_slave(dev, source_device, source_port);
if (!skb->dev)
return NULL;
/*
* 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);
}
return skb;
}
static const struct dsa_device_ops edsa_netdev_ops = {
.name = "edsa",
.proto = DSA_TAG_PROTO_EDSA,
.xmit = edsa_xmit,
.rcv = edsa_rcv,
.overhead = EDSA_HLEN,
};
MODULE_LICENSE("GPL");
MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_EDSA);
module_dsa_tag_driver(edsa_netdev_ops);