// 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>
#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)) {
- if (skb_cow_head(skb, 0) < 0)
- return NULL;
+ 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;
- dsa_header[0] = 0x60 | dp->ds->index;
+ /* 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 {
- if (skb_cow_head(skb, DSA_HLEN) < 0)
- return NULL;
- 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;
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)
+ 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;
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).
*/
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));
}
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 */
+
+#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;
-module_dsa_tag_driver(dsa_netdev_ops);
+ 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");
projects / linux-2.6-microblaze.git / blobdiff