| // SPDX-License-Identifier: GPL-2.0 |
| /* Copyright (c) 2019, Vladimir Oltean <olteanv@gmail.com> |
| * |
| * This module is not a complete tagger implementation. It only provides |
| * primitives for taggers that rely on 802.1Q VLAN tags to use. The |
| * dsa_8021q_netdev_ops is registered for API compliance and not used |
| * directly by callers. |
| */ |
| #include <linux/if_bridge.h> |
| #include <linux/if_vlan.h> |
| |
| #include "dsa_priv.h" |
| |
| /* Allocating two VLAN tags per port - one for the RX VID and |
| * the other for the TX VID - see below |
| */ |
| #define DSA_8021Q_VID_RANGE (DSA_MAX_SWITCHES * DSA_MAX_PORTS) |
| #define DSA_8021Q_VID_BASE (VLAN_N_VID - 2 * DSA_8021Q_VID_RANGE - 1) |
| #define DSA_8021Q_RX_VID_BASE (DSA_8021Q_VID_BASE) |
| #define DSA_8021Q_TX_VID_BASE (DSA_8021Q_VID_BASE + DSA_8021Q_VID_RANGE) |
| |
| /* Returns the VID to be inserted into the frame from xmit for switch steering |
| * instructions on egress. Encodes switch ID and port ID. |
| */ |
| u16 dsa_8021q_tx_vid(struct dsa_switch *ds, int port) |
| { |
| return DSA_8021Q_TX_VID_BASE + (DSA_MAX_PORTS * ds->index) + port; |
| } |
| EXPORT_SYMBOL_GPL(dsa_8021q_tx_vid); |
| |
| /* Returns the VID that will be installed as pvid for this switch port, sent as |
| * tagged egress towards the CPU port and decoded by the rcv function. |
| */ |
| u16 dsa_8021q_rx_vid(struct dsa_switch *ds, int port) |
| { |
| return DSA_8021Q_RX_VID_BASE + (DSA_MAX_PORTS * ds->index) + port; |
| } |
| EXPORT_SYMBOL_GPL(dsa_8021q_rx_vid); |
| |
| /* Returns the decoded switch ID from the RX VID. */ |
| int dsa_8021q_rx_switch_id(u16 vid) |
| { |
| return ((vid - DSA_8021Q_RX_VID_BASE) / DSA_MAX_PORTS); |
| } |
| EXPORT_SYMBOL_GPL(dsa_8021q_rx_switch_id); |
| |
| /* Returns the decoded port ID from the RX VID. */ |
| int dsa_8021q_rx_source_port(u16 vid) |
| { |
| return ((vid - DSA_8021Q_RX_VID_BASE) % DSA_MAX_PORTS); |
| } |
| EXPORT_SYMBOL_GPL(dsa_8021q_rx_source_port); |
| |
| /* RX VLAN tagging (left) and TX VLAN tagging (right) setup shown for a single |
| * front-panel switch port (here swp0). |
| * |
| * Port identification through VLAN (802.1Q) tags has different requirements |
| * for it to work effectively: |
| * - On RX (ingress from network): each front-panel port must have a pvid |
| * that uniquely identifies it, and the egress of this pvid must be tagged |
| * towards the CPU port, so that software can recover the source port based |
| * on the VID in the frame. But this would only work for standalone ports; |
| * if bridged, this VLAN setup would break autonomous forwarding and would |
| * force all switched traffic to pass through the CPU. So we must also make |
| * the other front-panel ports members of this VID we're adding, albeit |
| * we're not making it their PVID (they'll still have their own). |
| * By the way - just because we're installing the same VID in multiple |
| * switch ports doesn't mean that they'll start to talk to one another, even |
| * while not bridged: the final forwarding decision is still an AND between |
| * the L2 forwarding information (which is limiting forwarding in this case) |
| * and the VLAN-based restrictions (of which there are none in this case, |
| * since all ports are members). |
| * - On TX (ingress from CPU and towards network) we are faced with a problem. |
| * If we were to tag traffic (from within DSA) with the port's pvid, all |
| * would be well, assuming the switch ports were standalone. Frames would |
| * have no choice but to be directed towards the correct front-panel port. |
| * But because we also want the RX VLAN to not break bridging, then |
| * inevitably that means that we have to give them a choice (of what |
| * front-panel port to go out on), and therefore we cannot steer traffic |
| * based on the RX VID. So what we do is simply install one more VID on the |
| * front-panel and CPU ports, and profit off of the fact that steering will |
| * work just by virtue of the fact that there is only one other port that's |
| * a member of the VID we're tagging the traffic with - the desired one. |
| * |
| * So at the end, each front-panel port will have one RX VID (also the PVID), |
| * the RX VID of all other front-panel ports, and one TX VID. Whereas the CPU |
| * port will have the RX and TX VIDs of all front-panel ports, and on top of |
| * that, is also tagged-input and tagged-output (VLAN trunk). |
| * |
| * CPU port CPU port |
| * +-------------+-----+-------------+ +-------------+-----+-------------+ |
| * | RX VID | | | | TX VID | | | |
| * | of swp0 | | | | of swp0 | | | |
| * | +-----+ | | +-----+ | |
| * | ^ T | | | Tagged | |
| * | | | | | ingress | |
| * | +-------+---+---+-------+ | | +-----------+ | |
| * | | | | | | | | Untagged | |
| * | | U v U v U v | | v egress | |
| * | +-----+ +-----+ +-----+ +-----+ | | +-----+ +-----+ +-----+ +-----+ | |
| * | | | | | | | | | | | | | | | | | | | | |
| * | |PVID | | | | | | | | | | | | | | | | | | |
| * +-+-----+-+-----+-+-----+-+-----+-+ +-+-----+-+-----+-+-----+-+-----+-+ |
| * swp0 swp1 swp2 swp3 swp0 swp1 swp2 swp3 |
| */ |
| int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int port, bool enabled) |
| { |
| int upstream = dsa_upstream_port(ds, port); |
| struct dsa_port *dp = &ds->ports[port]; |
| struct dsa_port *upstream_dp = &ds->ports[upstream]; |
| u16 rx_vid = dsa_8021q_rx_vid(ds, port); |
| u16 tx_vid = dsa_8021q_tx_vid(ds, port); |
| int i, err; |
| |
| /* The CPU port is implicitly configured by |
| * configuring the front-panel ports |
| */ |
| if (!dsa_is_user_port(ds, port)) |
| return 0; |
| |
| /* Add this user port's RX VID to the membership list of all others |
| * (including itself). This is so that bridging will not be hindered. |
| * L2 forwarding rules still take precedence when there are no VLAN |
| * restrictions, so there are no concerns about leaking traffic. |
| */ |
| for (i = 0; i < ds->num_ports; i++) { |
| struct dsa_port *other_dp = &ds->ports[i]; |
| u16 flags; |
| |
| if (i == upstream) |
| /* CPU port needs to see this port's RX VID |
| * as tagged egress. |
| */ |
| flags = 0; |
| else if (i == port) |
| /* The RX VID is pvid on this port */ |
| flags = BRIDGE_VLAN_INFO_UNTAGGED | |
| BRIDGE_VLAN_INFO_PVID; |
| else |
| /* The RX VID is a regular VLAN on all others */ |
| flags = BRIDGE_VLAN_INFO_UNTAGGED; |
| |
| if (enabled) |
| err = dsa_port_vid_add(other_dp, rx_vid, flags); |
| else |
| err = dsa_port_vid_del(other_dp, rx_vid); |
| if (err) { |
| dev_err(ds->dev, "Failed to apply RX VID %d to port %d: %d\n", |
| rx_vid, port, err); |
| return err; |
| } |
| } |
| /* Finally apply the TX VID on this port and on the CPU port */ |
| if (enabled) |
| err = dsa_port_vid_add(dp, tx_vid, BRIDGE_VLAN_INFO_UNTAGGED); |
| else |
| err = dsa_port_vid_del(dp, tx_vid); |
| if (err) { |
| dev_err(ds->dev, "Failed to apply TX VID %d on port %d: %d\n", |
| tx_vid, port, err); |
| return err; |
| } |
| if (enabled) |
| err = dsa_port_vid_add(upstream_dp, tx_vid, 0); |
| else |
| err = dsa_port_vid_del(upstream_dp, tx_vid); |
| if (err) { |
| dev_err(ds->dev, "Failed to apply TX VID %d on port %d: %d\n", |
| tx_vid, upstream, err); |
| return err; |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(dsa_port_setup_8021q_tagging); |
| |
| struct sk_buff *dsa_8021q_xmit(struct sk_buff *skb, struct net_device *netdev, |
| u16 tpid, u16 tci) |
| { |
| /* skb->data points at skb_mac_header, which |
| * is fine for vlan_insert_tag. |
| */ |
| return vlan_insert_tag(skb, htons(tpid), tci); |
| } |
| EXPORT_SYMBOL_GPL(dsa_8021q_xmit); |
| |
| struct sk_buff *dsa_8021q_rcv(struct sk_buff *skb, struct net_device *netdev, |
| struct packet_type *pt, u16 *tpid, u16 *tci) |
| { |
| struct vlan_ethhdr *tag; |
| |
| if (unlikely(!pskb_may_pull(skb, VLAN_HLEN))) |
| return NULL; |
| |
| tag = vlan_eth_hdr(skb); |
| *tpid = ntohs(tag->h_vlan_proto); |
| *tci = ntohs(tag->h_vlan_TCI); |
| |
| /* skb->data points in the middle of the VLAN tag, |
| * after tpid and before tci. This is because so far, |
| * ETH_HLEN (DMAC, SMAC, EtherType) bytes were pulled. |
| * There are 2 bytes of VLAN tag left in skb->data, and upper |
| * layers expect the 'real' EtherType to be consumed as well. |
| * Coincidentally, a VLAN header is also of the same size as |
| * the number of bytes that need to be pulled. |
| */ |
| skb_pull_rcsum(skb, VLAN_HLEN); |
| |
| return skb; |
| } |
| EXPORT_SYMBOL_GPL(dsa_8021q_rcv); |
| |
| static const struct dsa_device_ops dsa_8021q_netdev_ops = { |
| .name = "8021q", |
| .proto = DSA_TAG_PROTO_8021Q, |
| .overhead = VLAN_HLEN, |
| }; |
| |
| MODULE_LICENSE("GPL v2"); |
| MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_8021Q); |
| |
| module_dsa_tag_driver(dsa_8021q_netdev_ops); |
