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Diffstat (limited to 'net/dsa/tag_dsa.c')
| -rw-r--r-- | net/dsa/tag_dsa.c | 406 |
1 files changed, 406 insertions, 0 deletions
diff --git a/net/dsa/tag_dsa.c b/net/dsa/tag_dsa.c new file mode 100644 index 000000000..e4b6e3f2a --- /dev/null +++ b/net/dsa/tag_dsa.c @@ -0,0 +1,406 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * 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/dsa/mv88e6xxx.h> +#include <linux/etherdevice.h> +#include <linux/list.h> +#include <linux/slab.h> + +#include "dsa_priv.h" + +#define DSA_HLEN 4 + +/** + * 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); + struct net_device *br_dev; + u8 tag_dev, tag_port; + enum dsa_cmd cmd; + u8 *dsa_header; + + if (skb->offload_fwd_mark) { + unsigned int bridge_num = dsa_port_bridge_num_get(dp); + struct dsa_switch_tree *dst = dp->ds->dst; + + cmd = DSA_CMD_FORWARD; + + /* When offloading forwarding for a bridge, inject FORWARD + * packets on behalf of a virtual switch device with an index + * past the physical switches. + */ + tag_dev = dst->last_switch + bridge_num; + tag_port = 0; + } else { + cmd = DSA_CMD_FROM_CPU; + tag_dev = dp->ds->index; + tag_port = dp->index; + } + + br_dev = dsa_port_bridge_dev_get(dp); + + /* If frame is already 802.1Q tagged, we can convert it to a DSA + * tag (avoiding a memmove), but only if the port is standalone + * (in which case we always send FROM_CPU) or if the port's + * bridge has VLAN filtering enabled (in which case the CPU port + * will be a member of the VLAN). + */ + if (skb->protocol == htons(ETH_P_8021Q) && + (!br_dev || br_vlan_enabled(br_dev))) { + if (extra) { + skb_push(skb, extra); + dsa_alloc_etype_header(skb, extra); + } + + /* Construct tagged DSA tag from 802.1Q tag. */ + dsa_header = dsa_etype_header_pos_tx(skb) + extra; + dsa_header[0] = (cmd << 6) | 0x20 | tag_dev; + dsa_header[1] = tag_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 { + u16 vid; + + vid = br_dev ? MV88E6XXX_VID_BRIDGED : MV88E6XXX_VID_STANDALONE; + + skb_push(skb, DSA_HLEN + extra); + dsa_alloc_etype_header(skb, DSA_HLEN + extra); + + /* Construct DSA header from untagged frame. */ + dsa_header = dsa_etype_header_pos_tx(skb) + extra; + + dsa_header[0] = (cmd << 6) | tag_dev; + dsa_header[1] = tag_port << 3; + dsa_header[2] = vid >> 8; + dsa_header[3] = vid & 0xff; + } + + return skb; +} + +static struct sk_buff *dsa_rcv_ll(struct sk_buff *skb, struct net_device *dev, + u8 extra) +{ + bool trap = false, trunk = false; + int source_device, source_port; + enum dsa_code code; + enum dsa_cmd cmd; + u8 *dsa_header; + + /* The ethertype field is part of the DSA header. */ + dsa_header = dsa_etype_header_pos_rx(skb); + + cmd = dsa_header[0] >> 6; + switch (cmd) { + case DSA_CMD_FORWARD: + trunk = !!(dsa_header[1] & 4); + 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. + */ + 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. + */ + trap = true; + break; + default: + /* Reserved code, this could be anything. Drop + * seems like the safest option. + */ + return NULL; + } + + break; + + default: + return NULL; + } + + source_device = dsa_header[0] & 0x1f; + source_port = (dsa_header[1] >> 3) & 0x1f; + + if (trunk) { + struct dsa_port *cpu_dp = dev->dsa_ptr; + struct dsa_lag *lag; + + /* The exact source port is not available in the tag, + * so we inject the frame directly on the upper + * team/bond. + */ + lag = dsa_lag_by_id(cpu_dp->dst, source_port + 1); + skb->dev = lag ? lag->dev : NULL; + } else { + skb->dev = dsa_master_find_slave(dev, source_device, + source_port); + } + + if (!skb->dev) + return NULL; + + /* When using LAG offload, skb->dev is not a DSA slave interface, + * so we cannot call dsa_default_offload_fwd_mark and we need to + * special-case it. + */ + if (trunk) + skb->offload_fwd_mark = true; + else if (!trap) + dsa_default_offload_fwd_mark(skb); + + /* 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 + * 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); + + if (extra) + dsa_strip_etype_header(skb, extra); + } else { + skb_pull_rcsum(skb, DSA_HLEN); + dsa_strip_etype_header(skb, DSA_HLEN + extra); + } + + 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) +{ + 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, + .needed_headroom = DSA_HLEN, +}; + +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; + + skb = dsa_xmit_ll(skb, dev, EDSA_HLEN - DSA_HLEN); + if (!skb) + return NULL; + + 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; + edsa_header[3] = 0x00; + return skb; +} + +static struct sk_buff *edsa_rcv(struct sk_buff *skb, struct net_device *dev) +{ + 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, + .needed_headroom = 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"); |