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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * net/dsa/tag_trailer.c - Trailer tag format handling
4 * Copyright (c) 2008-2009 Marvell Semiconductor
5 */
6
7#include <linux/etherdevice.h>
8#include <linux/list.h>
9#include <linux/slab.h>
10
11#include "dsa_priv.h"
12
13static struct sk_buff *trailer_xmit(struct sk_buff *skb, struct net_device *dev)
14{
15 struct dsa_port *dp = dsa_slave_to_port(dev);
16 u8 *trailer;
17
18 trailer = skb_put(skb, 4);
19 trailer[0] = 0x80;
20 trailer[1] = 1 << dp->index;
21 trailer[2] = 0x10;
22 trailer[3] = 0x00;
23
24 return skb;
25}
26
27static struct sk_buff *trailer_rcv(struct sk_buff *skb, struct net_device *dev,
28 struct packet_type *pt)
29{
30 u8 *trailer;
31 int source_port;
32
33 if (skb_linearize(skb))
34 return NULL;
35
36 trailer = skb_tail_pointer(skb) - 4;
37 if (trailer[0] != 0x80 || (trailer[1] & 0xf8) != 0x00 ||
38 (trailer[2] & 0xef) != 0x00 || trailer[3] != 0x00)
39 return NULL;
40
41 source_port = trailer[1] & 7;
42
43 skb->dev = dsa_master_find_slave(dev, 0, source_port);
44 if (!skb->dev)
45 return NULL;
46
47 if (pskb_trim_rcsum(skb, skb->len - 4))
48 return NULL;
49
50 return skb;
51}
52
53static const struct dsa_device_ops trailer_netdev_ops = {
54 .name = "trailer",
55 .proto = DSA_TAG_PROTO_TRAILER,
56 .xmit = trailer_xmit,
57 .rcv = trailer_rcv,
58 .needed_tailroom = 4,
59};
60
61MODULE_LICENSE("GPL");
62MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_TRAILER);
63
64module_dsa_tag_driver(trailer_netdev_ops);
1/*
2 * net/dsa/tag_trailer.c - Trailer tag format handling
3 * Copyright (c) 2008-2009 Marvell Semiconductor
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 */
10
11#include <linux/etherdevice.h>
12#include <linux/list.h>
13#include <linux/netdevice.h>
14#include <linux/slab.h>
15#include "dsa_priv.h"
16
17netdev_tx_t trailer_xmit(struct sk_buff *skb, struct net_device *dev)
18{
19 struct dsa_slave_priv *p = netdev_priv(dev);
20 struct sk_buff *nskb;
21 int padlen;
22 u8 *trailer;
23
24 dev->stats.tx_packets++;
25 dev->stats.tx_bytes += skb->len;
26
27 /*
28 * We have to make sure that the trailer ends up as the very
29 * last 4 bytes of the packet. This means that we have to pad
30 * the packet to the minimum ethernet frame size, if necessary,
31 * before adding the trailer.
32 */
33 padlen = 0;
34 if (skb->len < 60)
35 padlen = 60 - skb->len;
36
37 nskb = alloc_skb(NET_IP_ALIGN + skb->len + padlen + 4, GFP_ATOMIC);
38 if (nskb == NULL) {
39 kfree_skb(skb);
40 return NETDEV_TX_OK;
41 }
42 skb_reserve(nskb, NET_IP_ALIGN);
43
44 skb_reset_mac_header(nskb);
45 skb_set_network_header(nskb, skb_network_header(skb) - skb->head);
46 skb_set_transport_header(nskb, skb_transport_header(skb) - skb->head);
47 skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len));
48 kfree_skb(skb);
49
50 if (padlen) {
51 u8 *pad = skb_put(nskb, padlen);
52 memset(pad, 0, padlen);
53 }
54
55 trailer = skb_put(nskb, 4);
56 trailer[0] = 0x80;
57 trailer[1] = 1 << p->port;
58 trailer[2] = 0x10;
59 trailer[3] = 0x00;
60
61 nskb->protocol = htons(ETH_P_TRAILER);
62
63 nskb->dev = p->parent->dst->master_netdev;
64 dev_queue_xmit(nskb);
65
66 return NETDEV_TX_OK;
67}
68
69static int trailer_rcv(struct sk_buff *skb, struct net_device *dev,
70 struct packet_type *pt, struct net_device *orig_dev)
71{
72 struct dsa_switch_tree *dst = dev->dsa_ptr;
73 struct dsa_switch *ds;
74 u8 *trailer;
75 int source_port;
76
77 if (unlikely(dst == NULL))
78 goto out_drop;
79 ds = dst->ds[0];
80
81 skb = skb_unshare(skb, GFP_ATOMIC);
82 if (skb == NULL)
83 goto out;
84
85 if (skb_linearize(skb))
86 goto out_drop;
87
88 trailer = skb_tail_pointer(skb) - 4;
89 if (trailer[0] != 0x80 || (trailer[1] & 0xf8) != 0x00 ||
90 (trailer[3] & 0xef) != 0x00 || trailer[3] != 0x00)
91 goto out_drop;
92
93 source_port = trailer[1] & 7;
94 if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL)
95 goto out_drop;
96
97 pskb_trim_rcsum(skb, skb->len - 4);
98
99 skb->dev = ds->ports[source_port];
100 skb_push(skb, ETH_HLEN);
101 skb->pkt_type = PACKET_HOST;
102 skb->protocol = eth_type_trans(skb, skb->dev);
103
104 skb->dev->stats.rx_packets++;
105 skb->dev->stats.rx_bytes += skb->len;
106
107 netif_receive_skb(skb);
108
109 return 0;
110
111out_drop:
112 kfree_skb(skb);
113out:
114 return 0;
115}
116
117struct packet_type trailer_packet_type __read_mostly = {
118 .type = cpu_to_be16(ETH_P_TRAILER),
119 .func = trailer_rcv,
120};