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dfedd3b6 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
396138f0 LB |
2 | /* |
3 | * net/dsa/tag_trailer.c - Trailer tag format handling | |
e84665c9 | 4 | * Copyright (c) 2008-2009 Marvell Semiconductor |
396138f0 LB |
5 | */ |
6 | ||
7 | #include <linux/etherdevice.h> | |
8 | #include <linux/list.h> | |
5a0e3ad6 | 9 | #include <linux/slab.h> |
ea5dd34b | 10 | |
396138f0 LB |
11 | #include "dsa_priv.h" |
12 | ||
4ed70ce9 | 13 | static struct sk_buff *trailer_xmit(struct sk_buff *skb, struct net_device *dev) |
396138f0 | 14 | { |
d945097b | 15 | struct dsa_port *dp = dsa_slave_to_port(dev); |
396138f0 LB |
16 | struct sk_buff *nskb; |
17 | int padlen; | |
18 | u8 *trailer; | |
19 | ||
396138f0 LB |
20 | /* |
21 | * We have to make sure that the trailer ends up as the very | |
22 | * last 4 bytes of the packet. This means that we have to pad | |
23 | * the packet to the minimum ethernet frame size, if necessary, | |
24 | * before adding the trailer. | |
25 | */ | |
26 | padlen = 0; | |
27 | if (skb->len < 60) | |
28 | padlen = 60 - skb->len; | |
29 | ||
30 | nskb = alloc_skb(NET_IP_ALIGN + skb->len + padlen + 4, GFP_ATOMIC); | |
fe47d563 | 31 | if (!nskb) |
4ed70ce9 | 32 | return NULL; |
396138f0 LB |
33 | skb_reserve(nskb, NET_IP_ALIGN); |
34 | ||
35 | skb_reset_mac_header(nskb); | |
36 | skb_set_network_header(nskb, skb_network_header(skb) - skb->head); | |
37 | skb_set_transport_header(nskb, skb_transport_header(skb) - skb->head); | |
38 | skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len)); | |
2b33bc8a | 39 | consume_skb(skb); |
396138f0 LB |
40 | |
41 | if (padlen) { | |
b952f4df | 42 | skb_put_zero(nskb, padlen); |
396138f0 LB |
43 | } |
44 | ||
45 | trailer = skb_put(nskb, 4); | |
46 | trailer[0] = 0x80; | |
d945097b | 47 | trailer[1] = 1 << dp->index; |
396138f0 LB |
48 | trailer[2] = 0x10; |
49 | trailer[3] = 0x00; | |
50 | ||
4ed70ce9 | 51 | return nskb; |
396138f0 LB |
52 | } |
53 | ||
a86d8bec | 54 | static struct sk_buff *trailer_rcv(struct sk_buff *skb, struct net_device *dev, |
89e49506 | 55 | struct packet_type *pt) |
396138f0 | 56 | { |
396138f0 LB |
57 | u8 *trailer; |
58 | int source_port; | |
59 | ||
396138f0 | 60 | if (skb_linearize(skb)) |
54709795 | 61 | return NULL; |
396138f0 LB |
62 | |
63 | trailer = skb_tail_pointer(skb) - 4; | |
64 | if (trailer[0] != 0x80 || (trailer[1] & 0xf8) != 0x00 || | |
fbd03513 | 65 | (trailer[2] & 0xef) != 0x00 || trailer[3] != 0x00) |
54709795 | 66 | return NULL; |
396138f0 LB |
67 | |
68 | source_port = trailer[1] & 7; | |
3775b1b7 | 69 | |
2231c43b | 70 | skb->dev = dsa_master_find_slave(dev, 0, source_port); |
3775b1b7 | 71 | if (!skb->dev) |
54709795 | 72 | return NULL; |
396138f0 | 73 | |
349b71d6 ZJ |
74 | if (pskb_trim_rcsum(skb, skb->len - 4)) |
75 | return NULL; | |
396138f0 | 76 | |
a86d8bec | 77 | return skb; |
396138f0 LB |
78 | } |
79 | ||
f81a43e8 | 80 | static const struct dsa_device_ops trailer_netdev_ops = { |
875138f8 | 81 | .name = "trailer", |
056eed2f | 82 | .proto = DSA_TAG_PROTO_TRAILER, |
3e8a72d1 FF |
83 | .xmit = trailer_xmit, |
84 | .rcv = trailer_rcv, | |
a5dd3087 | 85 | .overhead = 4, |
396138f0 | 86 | }; |
0b42f033 | 87 | |
f18bba50 | 88 | MODULE_LICENSE("GPL"); |
0b42f033 | 89 | MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_TRAILER); |
d3b8c049 AL |
90 | |
91 | module_dsa_tag_driver(trailer_netdev_ops); |