/* * Copyright (C) 2017 Pengutronix, Juergen Borleis * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * */ #include #include #include #include #include "dsa_priv.h" /* To define the outgoing port and to discover the incoming port a regular * VLAN tag is used by the LAN9303. But its VID meaning is 'special': * * Dest MAC Src MAC TAG Type * ...| 1 2 3 4 5 6 | 1 2 3 4 5 6 | 1 2 3 4 | 1 2 |... * |<------->| * TAG: * |<------------->| * | 1 2 | 3 4 | * TPID VID * 0x8100 * * VID bit 3 indicates a request for an ALR lookup. * * If VID bit 3 is zero, then bits 0 and 1 specify the destination port * (0, 1, 2) or broadcast (3) or the source port (1, 2). * * VID bit 4 is used to specify if the STP port state should be overridden. * Required when no forwarding between the external ports should happen. */ #define LAN9303_TAG_LEN 4 # define LAN9303_TAG_TX_USE_ALR BIT(3) # define LAN9303_TAG_TX_STP_OVERRIDE BIT(4) #define eth_stp_addr eth_reserved_addr_base /* Decide whether to transmit using ALR lookup, or transmit directly to * port using tag. ALR learning is performed only when using ALR lookup. * If the two external ports are bridged and the packet is not STP BPDU, * then use ALR lookup to allow ALR learning on CPU port. * Otherwise transmit directly to port with STP state override. * See also: lan9303_separate_ports() and lan9303.pdf 6.4.10.1 */ static int lan9303_xmit_use_arl(struct dsa_port *dp, u8 *dest_addr) { struct lan9303 *chip = dp->ds->priv; return chip->is_bridged && !ether_addr_equal(dest_addr, eth_stp_addr); } static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev) { struct dsa_port *dp = dsa_slave_to_port(dev); u16 *lan9303_tag; /* insert a special VLAN tag between the MAC addresses * and the current ethertype field. */ if (skb_cow_head(skb, LAN9303_TAG_LEN) < 0) { dev_dbg(&dev->dev, "Cannot make room for the special tag. Dropping packet\n"); return NULL; } /* provide 'LAN9303_TAG_LEN' bytes additional space */ skb_push(skb, LAN9303_TAG_LEN); /* make room between MACs and Ether-Type */ memmove(skb->data, skb->data + LAN9303_TAG_LEN, 2 * ETH_ALEN); lan9303_tag = (u16 *)(skb->data + 2 * ETH_ALEN); lan9303_tag[0] = htons(ETH_P_8021Q); lan9303_tag[1] = lan9303_xmit_use_arl(dp, skb->data) ? LAN9303_TAG_TX_USE_ALR : dp->index | LAN9303_TAG_TX_STP_OVERRIDE; lan9303_tag[1] = htons(lan9303_tag[1]); return skb; } static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt) { u16 *lan9303_tag; unsigned int source_port; if (unlikely(!pskb_may_pull(skb, LAN9303_TAG_LEN))) { dev_warn_ratelimited(&dev->dev, "Dropping packet, cannot pull\n"); return NULL; } /* '->data' points into the middle of our special VLAN tag information: * * ~ MAC src | 0x81 | 0x00 | 0xyy | 0xzz | ether type * ^ * ->data */ lan9303_tag = (u16 *)(skb->data - 2); if (lan9303_tag[0] != htons(ETH_P_8021Q)) { dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid VLAN marker\n"); return NULL; } source_port = ntohs(lan9303_tag[1]) & 0x3; skb->dev = dsa_master_find_slave(dev, 0, source_port); if (!skb->dev) { dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid source port\n"); return NULL; } /* remove the special VLAN tag between the MAC addresses * 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); return skb; } const struct dsa_device_ops lan9303_netdev_ops = { .xmit = lan9303_xmit, .rcv = lan9303_rcv, };