tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2019, Vladimir Oltean <olteanv@gmail.com>
3 */
4#include <linux/if_vlan.h>
5#include <linux/dsa/sja1105.h>
6#include <linux/dsa/8021q.h>
7#include <linux/packing.h>
8#include "dsa_priv.h"
9
10/* Similar to is_link_local_ether_addr(hdr->h_dest) but also covers PTP */
11static inline bool sja1105_is_link_local(const struct sk_buff *skb)
12{
13 const struct ethhdr *hdr = eth_hdr(skb);
14 u64 dmac = ether_addr_to_u64(hdr->h_dest);
15
16 if ((dmac & SJA1105_LINKLOCAL_FILTER_A_MASK) ==
17 SJA1105_LINKLOCAL_FILTER_A)
18 return true;
19 if ((dmac & SJA1105_LINKLOCAL_FILTER_B_MASK) ==
20 SJA1105_LINKLOCAL_FILTER_B)
21 return true;
22 return false;
23}
24
25/* This is the first time the tagger sees the frame on RX.
26 * Figure out if we can decode it, and if we can, annotate skb->cb with how we
27 * plan to do that, so we don't need to check again in the rcv function.
28 */
29static bool sja1105_filter(const struct sk_buff *skb, struct net_device *dev)
30{
31 if (sja1105_is_link_local(skb))
32 return true;
33 if (!dsa_port_is_vlan_filtering(dev->dsa_ptr))
34 return true;
35 return false;
36}
37
38static struct sk_buff *sja1105_xmit(struct sk_buff *skb,
39 struct net_device *netdev)
40{
41 struct dsa_port *dp = dsa_slave_to_port(netdev);
42 struct dsa_switch *ds = dp->ds;
43 u16 tx_vid = dsa_8021q_tx_vid(ds, dp->index);
44 u8 pcp = skb->priority;
45
46 /* Transmitting management traffic does not rely upon switch tagging,
47 * but instead SPI-installed management routes. Part 2 of this
48 * is the .port_deferred_xmit driver callback.
49 */
50 if (unlikely(sja1105_is_link_local(skb)))
51 return dsa_defer_xmit(skb, netdev);
52
53 /* If we are under a vlan_filtering bridge, IP termination on
54 * switch ports based on 802.1Q tags is simply too brittle to
55 * be passable. So just defer to the dsa_slave_notag_xmit
56 * implementation.
57 */
58 if (dsa_port_is_vlan_filtering(dp))
59 return skb;
60
61 return dsa_8021q_xmit(skb, netdev, ETH_P_SJA1105,
62 ((pcp << VLAN_PRIO_SHIFT) | tx_vid));
63}
64
65static struct sk_buff *sja1105_rcv(struct sk_buff *skb,
66 struct net_device *netdev,
67 struct packet_type *pt)
68{
69 struct ethhdr *hdr = eth_hdr(skb);
70 u64 source_port, switch_id;
71 struct sk_buff *nskb;
72 u16 tpid, vid, tci;
73 bool is_tagged;
74
75 nskb = dsa_8021q_rcv(skb, netdev, pt, &tpid, &tci);
76 is_tagged = (nskb && tpid == ETH_P_SJA1105);
77
78 skb->priority = (tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
79 vid = tci & VLAN_VID_MASK;
80
81 skb->offload_fwd_mark = 1;
82
83 if (sja1105_is_link_local(skb)) {
84 /* Management traffic path. Switch embeds the switch ID and
85 * port ID into bytes of the destination MAC, courtesy of
86 * the incl_srcpt options.
87 */
88 source_port = hdr->h_dest[3];
89 switch_id = hdr->h_dest[4];
90 /* Clear the DMAC bytes that were mangled by the switch */
91 hdr->h_dest[3] = 0;
92 hdr->h_dest[4] = 0;
93 } else {
94 /* Normal traffic path. */
95 source_port = dsa_8021q_rx_source_port(vid);
96 switch_id = dsa_8021q_rx_switch_id(vid);
97 }
98
99 skb->dev = dsa_master_find_slave(netdev, switch_id, source_port);
100 if (!skb->dev) {
101 netdev_warn(netdev, "Couldn't decode source port\n");
102 return NULL;
103 }
104
105 /* Delete/overwrite fake VLAN header, DSA expects to not find
106 * it there, see dsa_switch_rcv: skb_push(skb, ETH_HLEN).
107 */
108 if (is_tagged)
109 memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - VLAN_HLEN,
110 ETH_HLEN - VLAN_HLEN);
111
112 return skb;
113}
114
115static struct dsa_device_ops sja1105_netdev_ops = {
116 .name = "sja1105",
117 .proto = DSA_TAG_PROTO_SJA1105,
118 .xmit = sja1105_xmit,
119 .rcv = sja1105_rcv,
120 .filter = sja1105_filter,
121 .overhead = VLAN_HLEN,
122};
123
124MODULE_LICENSE("GPL v2");
125MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_SJA1105);
126
127module_dsa_tag_driver(sja1105_netdev_ops);