// SPDX-License-Identifier: GPL-2.0 /* Copyright (c) 2019, Vladimir Oltean */ #include #include #include #include #include "dsa_priv.h" /* Similar to is_link_local_ether_addr(hdr->h_dest) but also covers PTP */ static inline bool sja1105_is_link_local(const struct sk_buff *skb) { const struct ethhdr *hdr = eth_hdr(skb); u64 dmac = ether_addr_to_u64(hdr->h_dest); if (ntohs(hdr->h_proto) == ETH_P_SJA1105_META) return false; if ((dmac & SJA1105_LINKLOCAL_FILTER_A_MASK) == SJA1105_LINKLOCAL_FILTER_A) return true; if ((dmac & SJA1105_LINKLOCAL_FILTER_B_MASK) == SJA1105_LINKLOCAL_FILTER_B) return true; return false; } struct sja1105_meta { u64 tstamp; u64 dmac_byte_4; u64 dmac_byte_3; u64 source_port; u64 switch_id; }; static void sja1105_meta_unpack(const struct sk_buff *skb, struct sja1105_meta *meta) { u8 *buf = skb_mac_header(skb) + ETH_HLEN; /* UM10944.pdf section 4.2.17 AVB Parameters: * Structure of the meta-data follow-up frame. * It is in network byte order, so there are no quirks * while unpacking the meta frame. * * Also SJA1105 E/T only populates bits 23:0 of the timestamp * whereas P/Q/R/S does 32 bits. Since the structure is the * same and the E/T puts zeroes in the high-order byte, use * a unified unpacking command for both device series. */ packing(buf, &meta->tstamp, 31, 0, 4, UNPACK, 0); packing(buf + 4, &meta->dmac_byte_4, 7, 0, 1, UNPACK, 0); packing(buf + 5, &meta->dmac_byte_3, 7, 0, 1, UNPACK, 0); packing(buf + 6, &meta->source_port, 7, 0, 1, UNPACK, 0); packing(buf + 7, &meta->switch_id, 7, 0, 1, UNPACK, 0); } static inline bool sja1105_is_meta_frame(const struct sk_buff *skb) { const struct ethhdr *hdr = eth_hdr(skb); u64 smac = ether_addr_to_u64(hdr->h_source); u64 dmac = ether_addr_to_u64(hdr->h_dest); if (smac != SJA1105_META_SMAC) return false; if (dmac != SJA1105_META_DMAC) return false; if (ntohs(hdr->h_proto) != ETH_P_SJA1105_META) return false; return true; } /* This is the first time the tagger sees the frame on RX. * Figure out if we can decode it. */ static bool sja1105_filter(const struct sk_buff *skb, struct net_device *dev) { if (!dsa_port_is_vlan_filtering(dev->dsa_ptr)) return true; if (sja1105_is_link_local(skb)) return true; if (sja1105_is_meta_frame(skb)) return true; return false; } /* Calls sja1105_port_deferred_xmit in sja1105_main.c */ static struct sk_buff *sja1105_defer_xmit(struct sja1105_port *sp, struct sk_buff *skb) { /* Increase refcount so the kfree_skb in dsa_slave_xmit * won't really free the packet. */ skb_queue_tail(&sp->xmit_queue, skb_get(skb)); kthread_queue_work(sp->xmit_worker, &sp->xmit_work); return NULL; } static struct sk_buff *sja1105_xmit(struct sk_buff *skb, struct net_device *netdev) { struct dsa_port *dp = dsa_slave_to_port(netdev); u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index); u16 queue_mapping = skb_get_queue_mapping(skb); u8 pcp = netdev_txq_to_tc(netdev, queue_mapping); /* Transmitting management traffic does not rely upon switch tagging, * but instead SPI-installed management routes. Part 2 of this * is the .port_deferred_xmit driver callback. */ if (unlikely(sja1105_is_link_local(skb))) return sja1105_defer_xmit(dp->priv, skb); /* If we are under a vlan_filtering bridge, IP termination on * switch ports based on 802.1Q tags is simply too brittle to * be passable. So just defer to the dsa_slave_notag_xmit * implementation. */ if (dsa_port_is_vlan_filtering(dp)) return skb; return dsa_8021q_xmit(skb, netdev, ETH_P_SJA1105, ((pcp << VLAN_PRIO_SHIFT) | tx_vid)); } static void sja1105_transfer_meta(struct sk_buff *skb, const struct sja1105_meta *meta) { struct ethhdr *hdr = eth_hdr(skb); hdr->h_dest[3] = meta->dmac_byte_3; hdr->h_dest[4] = meta->dmac_byte_4; SJA1105_SKB_CB(skb)->meta_tstamp = meta->tstamp; } /* This is a simple state machine which follows the hardware mechanism of * generating RX timestamps: * * After each timestampable skb (all traffic for which send_meta1 and * send_meta0 is true, aka all MAC-filtered link-local traffic) a meta frame * containing a partial timestamp is immediately generated by the switch and * sent as a follow-up to the link-local frame on the CPU port. * * The meta frames have no unique identifier (such as sequence number) by which * one may pair them to the correct timestampable frame. * Instead, the switch has internal logic that ensures no frames are sent on * the CPU port between a link-local timestampable frame and its corresponding * meta follow-up. It also ensures strict ordering between ports (lower ports * have higher priority towards the CPU port). For this reason, a per-port * data structure is not needed/desirable. * * This function pairs the link-local frame with its partial timestamp from the * meta follow-up frame. The full timestamp will be reconstructed later in a * work queue. */ static struct sk_buff *sja1105_rcv_meta_state_machine(struct sk_buff *skb, struct sja1105_meta *meta, bool is_link_local, bool is_meta) { struct sja1105_port *sp; struct dsa_port *dp; dp = dsa_slave_to_port(skb->dev); sp = dp->priv; /* Step 1: A timestampable frame was received. * Buffer it until we get its meta frame. */ if (is_link_local) { if (!test_bit(SJA1105_HWTS_RX_EN, &sp->data->state)) /* Do normal processing. */ return skb; spin_lock(&sp->data->meta_lock); /* Was this a link-local frame instead of the meta * that we were expecting? */ if (sp->data->stampable_skb) { dev_err_ratelimited(dp->ds->dev, "Expected meta frame, is %12llx " "in the DSA master multicast filter?\n", SJA1105_META_DMAC); kfree_skb(sp->data->stampable_skb); } /* Hold a reference to avoid dsa_switch_rcv * from freeing the skb. */ sp->data->stampable_skb = skb_get(skb); spin_unlock(&sp->data->meta_lock); /* Tell DSA we got nothing */ return NULL; /* Step 2: The meta frame arrived. * Time to take the stampable skb out of the closet, annotate it * with the partial timestamp, and pretend that we received it * just now (basically masquerade the buffered frame as the meta * frame, which serves no further purpose). */ } else if (is_meta) { struct sk_buff *stampable_skb; /* Drop the meta frame if we're not in the right state * to process it. */ if (!test_bit(SJA1105_HWTS_RX_EN, &sp->data->state)) return NULL; spin_lock(&sp->data->meta_lock); stampable_skb = sp->data->stampable_skb; sp->data->stampable_skb = NULL; /* Was this a meta frame instead of the link-local * that we were expecting? */ if (!stampable_skb) { dev_err_ratelimited(dp->ds->dev, "Unexpected meta frame\n"); spin_unlock(&sp->data->meta_lock); return NULL; } if (stampable_skb->dev != skb->dev) { dev_err_ratelimited(dp->ds->dev, "Meta frame on wrong port\n"); spin_unlock(&sp->data->meta_lock); return NULL; } /* Free the meta frame and give DSA the buffered stampable_skb * for further processing up the network stack. */ kfree_skb(skb); skb = stampable_skb; sja1105_transfer_meta(skb, meta); spin_unlock(&sp->data->meta_lock); } return skb; } static struct sk_buff *sja1105_rcv(struct sk_buff *skb, struct net_device *netdev, struct packet_type *pt) { struct sja1105_meta meta = {0}; int source_port, switch_id; struct vlan_ethhdr *hdr; u16 tpid, vid, tci; bool is_link_local; bool is_tagged; bool is_meta; hdr = vlan_eth_hdr(skb); tpid = ntohs(hdr->h_vlan_proto); is_tagged = (tpid == ETH_P_SJA1105); is_link_local = sja1105_is_link_local(skb); is_meta = sja1105_is_meta_frame(skb); skb->offload_fwd_mark = 1; if (is_tagged) { /* Normal traffic path. */ tci = ntohs(hdr->h_vlan_TCI); vid = tci & VLAN_VID_MASK; source_port = dsa_8021q_rx_source_port(vid); switch_id = dsa_8021q_rx_switch_id(vid); skb->priority = (tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT; } else if (is_link_local) { /* Management traffic path. Switch embeds the switch ID and * port ID into bytes of the destination MAC, courtesy of * the incl_srcpt options. */ source_port = hdr->h_dest[3]; switch_id = hdr->h_dest[4]; /* Clear the DMAC bytes that were mangled by the switch */ hdr->h_dest[3] = 0; hdr->h_dest[4] = 0; } else if (is_meta) { sja1105_meta_unpack(skb, &meta); source_port = meta.source_port; switch_id = meta.switch_id; } else { return NULL; } skb->dev = dsa_master_find_slave(netdev, switch_id, source_port); if (!skb->dev) { netdev_warn(netdev, "Couldn't decode source port\n"); return NULL; } /* Delete/overwrite fake VLAN header, DSA expects to not find * it there, see dsa_switch_rcv: skb_push(skb, ETH_HLEN). */ if (is_tagged) skb = dsa_8021q_remove_header(skb); return sja1105_rcv_meta_state_machine(skb, &meta, is_link_local, is_meta); } static struct dsa_device_ops sja1105_netdev_ops = { .name = "sja1105", .proto = DSA_TAG_PROTO_SJA1105, .xmit = sja1105_xmit, .rcv = sja1105_rcv, .filter = sja1105_filter, .overhead = VLAN_HLEN, }; MODULE_LICENSE("GPL v2"); MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_SJA1105); module_dsa_tag_driver(sja1105_netdev_ops);