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
117static struct packet_type trailer_packet_type __read_mostly = {
118	.type	= cpu_to_be16(ETH_P_TRAILER),
119	.func	= trailer_rcv,
 
 
 
120};
121
122static int __init trailer_init_module(void)
123{
124	dev_add_pack(&trailer_packet_type);
125	return 0;
126}
127module_init(trailer_init_module);
128
129static void __exit trailer_cleanup_module(void)
130{
131	dev_remove_pack(&trailer_packet_type);
132}
133module_exit(trailer_cleanup_module);

 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 "tag.h"
 
 
 
 
 
12
13#define TRAILER_NAME "trailer"
 
14
15static struct sk_buff *trailer_xmit(struct sk_buff *skb, struct net_device *dev)
16{
17	struct dsa_port *dp = dsa_user_to_port(dev);
18	u8 *trailer;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
19
20	trailer = skb_put(skb, 4);
21	trailer[0] = 0x80;
22	trailer[1] = 1 << dp->index;
23	trailer[2] = 0x10;
24	trailer[3] = 0x00;
25
26	return skb;
 
 
 
 
 
27}
28
29static struct sk_buff *trailer_rcv(struct sk_buff *skb, struct net_device *dev)
 
30{
 
 
31	u8 *trailer;
32	int source_port;
33
 
 
 
 
 
 
 
 
34	if (skb_linearize(skb))
35		return NULL;
36
37	trailer = skb_tail_pointer(skb) - 4;
38	if (trailer[0] != 0x80 || (trailer[1] & 0xf8) != 0x00 ||
39	    (trailer[2] & 0xef) != 0x00 || trailer[3] != 0x00)
40		return NULL;
41
42	source_port = trailer[1] & 7;
 
 
43
44	skb->dev = dsa_conduit_find_user(dev, 0, source_port);
45	if (!skb->dev)
46		return NULL;
47
48	if (pskb_trim_rcsum(skb, skb->len - 4))
49		return NULL;
 
 
50
51	return skb;
 
 
 
 
 
 
 
 
 
 
52}
53
54static const struct dsa_device_ops trailer_netdev_ops = {
55	.name	= TRAILER_NAME,
56	.proto	= DSA_TAG_PROTO_TRAILER,
57	.xmit	= trailer_xmit,
58	.rcv	= trailer_rcv,
59	.needed_tailroom = 4,
60};
61
62MODULE_DESCRIPTION("DSA tag driver for switches using a trailer tag");
63MODULE_LICENSE("GPL");
64MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_TRAILER, TRAILER_NAME);
 
 
 
65
66module_dsa_tag_driver(trailer_netdev_ops);