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/slab.h>
 
 14#include "dsa_priv.h"
 15
 16static struct sk_buff *trailer_xmit(struct sk_buff *skb, struct net_device *dev)
 17{
 18	struct dsa_slave_priv *p = netdev_priv(dev);
 19	struct sk_buff *nskb;
 20	int padlen;
 21	u8 *trailer;
 22
 23	/*
 24	 * We have to make sure that the trailer ends up as the very
 25	 * last 4 bytes of the packet.  This means that we have to pad
 26	 * the packet to the minimum ethernet frame size, if necessary,
 27	 * before adding the trailer.
 28	 */
 29	padlen = 0;
 30	if (skb->len < 60)
 31		padlen = 60 - skb->len;
 32
 33	nskb = alloc_skb(NET_IP_ALIGN + skb->len + padlen + 4, GFP_ATOMIC);
 34	if (nskb == NULL) {
 35		kfree_skb(skb);
 36		return NULL;
 37	}
 38	skb_reserve(nskb, NET_IP_ALIGN);
 39
 40	skb_reset_mac_header(nskb);
 41	skb_set_network_header(nskb, skb_network_header(skb) - skb->head);
 42	skb_set_transport_header(nskb, skb_transport_header(skb) - skb->head);
 43	skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len));
 44	kfree_skb(skb);
 45
 46	if (padlen) {
 47		u8 *pad = skb_put(nskb, padlen);
 48		memset(pad, 0, padlen);
 49	}
 50
 51	trailer = skb_put(nskb, 4);
 52	trailer[0] = 0x80;
 53	trailer[1] = 1 << p->port;
 54	trailer[2] = 0x10;
 55	trailer[3] = 0x00;
 56
 57	return nskb;
 58}
 59
 60static int trailer_rcv(struct sk_buff *skb, struct net_device *dev,
 61		       struct packet_type *pt, struct net_device *orig_dev)
 62{
 63	struct dsa_switch_tree *dst = dev->dsa_ptr;
 64	struct dsa_switch *ds;
 65	u8 *trailer;
 66	int source_port;
 67
 68	if (unlikely(dst == NULL))
 69		goto out_drop;
 70	ds = dst->ds[0];
 71
 72	skb = skb_unshare(skb, GFP_ATOMIC);
 73	if (skb == NULL)
 74		goto out;
 75
 76	if (skb_linearize(skb))
 77		goto out_drop;
 78
 79	trailer = skb_tail_pointer(skb) - 4;
 80	if (trailer[0] != 0x80 || (trailer[1] & 0xf8) != 0x00 ||
 81	    (trailer[2] & 0xef) != 0x00 || trailer[3] != 0x00)
 82		goto out_drop;
 83
 84	source_port = trailer[1] & 7;
 85	if (source_port >= DSA_MAX_PORTS || !ds->ports[source_port].netdev)
 86		goto out_drop;
 87
 88	pskb_trim_rcsum(skb, skb->len - 4);
 
 
 89
 90	skb->dev = ds->ports[source_port].netdev;
 91	skb_push(skb, ETH_HLEN);
 92	skb->pkt_type = PACKET_HOST;
 93	skb->protocol = eth_type_trans(skb, skb->dev);
 94
 95	skb->dev->stats.rx_packets++;
 96	skb->dev->stats.rx_bytes += skb->len;
 97
 98	netif_receive_skb(skb);
 99
100	return 0;
101
102out_drop:
103	kfree_skb(skb);
104out:
105	return 0;
106}
107
108const struct dsa_device_ops trailer_netdev_ops = {
 
 
109	.xmit	= trailer_xmit,
110	.rcv	= trailer_rcv,
 
111};