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| 3 | * net/dsa/tag_trailer.c - Trailer tag format handling
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| 4 | * Copyright (c) 2008-2009 Marvell Semiconductor
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| 5 |
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| 6 |
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| 7 | #include <linux/etherdevice.h>
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| 8 | #include <linux/list.h>
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| 9 | #include <linux/slab.h>
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| 10 |
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| 11 | #include "tag.h"
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| 12 |
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| 13 | #define TRAILER_NAME "trailer"
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| 14 |
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| 15 | static struct sk_buff *trailer_xmit(struct sk_buff *skb, struct net_device *dev)
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| 16 | {
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| 17 | u8 *trailer;
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| 18 |
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| 19 | trailer = skb_put(skb, 4);
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| 20 | trailer[0] = 0x80;
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| 21 | trailer[1] = dsa_xmit_port_mask(skb, dev);
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| 22 | trailer[2] = 0x10;
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| 23 | trailer[3] = 0x00;
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| 24 |
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| 25 | return skb;
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| 26 | }
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| 27 |
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| 28 | static struct sk_buff *trailer_rcv(struct sk_buff *skb, struct net_device *dev)
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| 29 | {
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| 30 | u8 *trailer;
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| 31 | int source_port;
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| 32 |
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| 33 | if (skb_linearize(skb)) {
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| 34 | kfree_skb(skb);
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| 35 | return NULL;
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| 36 | }
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| 37 |
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| 38 | trailer = skb_tail_pointer(skb) - 4;
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| 39 | if (trailer[0] != 0x80 || (trailer[1] & 0xf8) != 0x00 ||
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| 40 | (trailer[2] & 0xef) != 0x00 || trailer[3] != 0x00) {
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| 41 | kfree_skb(skb);
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| 42 | return NULL;
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| 43 | }
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| 44 |
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| 45 | source_port = trailer[1] & 7;
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| 46 |
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| 47 | skb->dev = dsa_conduit_find_user(dev, 0, source_port);
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| 48 | if (!skb->dev) {
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| 49 | kfree_skb(skb);
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| 50 | return NULL;
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| 51 | }
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| 52 |
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| 53 | if (pskb_trim_rcsum(skb, skb->len - 4)) {
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| 54 | kfree_skb(skb);
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| 55 | return NULL;
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| 56 | }
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| 57 |
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| 58 | return skb;
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| 59 | }
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| 60 |
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| 61 | static const struct dsa_device_ops trailer_netdev_ops = {
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| 62 | .name = TRAILER_NAME,
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| 63 | .proto = DSA_TAG_PROTO_TRAILER,
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| 64 | .xmit = trailer_xmit,
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| 65 | .rcv = trailer_rcv,
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| 66 | .needed_tailroom = 4,
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| 67 | };
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| 68 |
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| 69 | MODULE_DESCRIPTION("DSA tag driver for switches using a trailer tag");
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| 70 | MODULE_LICENSE("GPL");
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| 71 | MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_TRAILER, TRAILER_NAME);
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| 72 |
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| 73 | module_dsa_tag_driver(trailer_netdev_ops);
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