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1 | /* |
2 | * STP SAP demux |
3 | * |
4 | * Copyright (c) 2008 Patrick McHardy <kaber@trash.net> |
5 | * |
6 | * This program is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU General Public License |
8 | * version 2 as published by the Free Software Foundation. |
9 | */ |
10 | #include <linux/mutex.h> |
11 | #include <linux/skbuff.h> |
12 | #include <linux/etherdevice.h> |
13 | #include <linux/llc.h> |
14 | #include <linux/slab.h> |
15 | #include <linux/module.h> |
16 | #include <net/llc.h> |
17 | #include <net/llc_pdu.h> |
18 | #include <net/stp.h> |
19 | |
20 | /* 01:80:c2:00:00:20 - 01:80:c2:00:00:2F */ |
21 | #define GARP_ADDR_MIN 0x20 |
22 | #define GARP_ADDR_MAX 0x2F |
23 | #define GARP_ADDR_RANGE (GARP_ADDR_MAX - GARP_ADDR_MIN) |
24 | |
25 | static const struct stp_proto __rcu *garp_protos[GARP_ADDR_RANGE + 1] __read_mostly; |
26 | static const struct stp_proto __rcu *stp_proto __read_mostly; |
27 | |
28 | static struct llc_sap *sap __read_mostly; |
29 | static unsigned int sap_registered; |
30 | static DEFINE_MUTEX(stp_proto_mutex); |
31 | |
32 | /* Called under rcu_read_lock from LLC */ |
33 | static int stp_pdu_rcv(struct sk_buff *skb, struct net_device *dev, |
34 | struct packet_type *pt, struct net_device *orig_dev) |
35 | { |
36 | const struct ethhdr *eh = eth_hdr(skb); |
37 | const struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb); |
38 | const struct stp_proto *proto; |
39 | |
40 | if (pdu->ssap != LLC_SAP_BSPAN || |
41 | pdu->dsap != LLC_SAP_BSPAN || |
42 | pdu->ctrl_1 != LLC_PDU_TYPE_U) |
43 | goto err; |
44 | |
45 | if (eh->h_dest[5] >= GARP_ADDR_MIN && eh->h_dest[5] <= GARP_ADDR_MAX) { |
46 | proto = rcu_dereference(garp_protos[eh->h_dest[5] - |
47 | GARP_ADDR_MIN]); |
48 | if (proto && |
49 | !ether_addr_equal(eh->h_dest, proto->group_address)) |
50 | goto err; |
51 | } else |
52 | proto = rcu_dereference(stp_proto); |
53 | |
54 | if (!proto) |
55 | goto err; |
56 | |
57 | proto->rcv(proto, skb, dev); |
58 | return 0; |
59 | |
60 | err: |
61 | kfree_skb(skb); |
62 | return 0; |
63 | } |
64 | |
65 | int stp_proto_register(const struct stp_proto *proto) |
66 | { |
67 | int err = 0; |
68 | |
69 | mutex_lock(&stp_proto_mutex); |
70 | if (sap_registered++ == 0) { |
71 | sap = llc_sap_open(LLC_SAP_BSPAN, stp_pdu_rcv); |
72 | if (!sap) { |
73 | err = -ENOMEM; |
74 | goto out; |
75 | } |
76 | } |
77 | if (is_zero_ether_addr(proto->group_address)) |
78 | rcu_assign_pointer(stp_proto, proto); |
79 | else |
80 | rcu_assign_pointer(garp_protos[proto->group_address[5] - |
81 | GARP_ADDR_MIN], proto); |
82 | out: |
83 | mutex_unlock(&stp_proto_mutex); |
84 | return err; |
85 | } |
86 | EXPORT_SYMBOL_GPL(stp_proto_register); |
87 | |
88 | void stp_proto_unregister(const struct stp_proto *proto) |
89 | { |
90 | mutex_lock(&stp_proto_mutex); |
91 | if (is_zero_ether_addr(proto->group_address)) |
92 | RCU_INIT_POINTER(stp_proto, NULL); |
93 | else |
94 | RCU_INIT_POINTER(garp_protos[proto->group_address[5] - |
95 | GARP_ADDR_MIN], NULL); |
96 | synchronize_rcu(); |
97 | |
98 | if (--sap_registered == 0) |
99 | llc_sap_put(sap); |
100 | mutex_unlock(&stp_proto_mutex); |
101 | } |
102 | EXPORT_SYMBOL_GPL(stp_proto_unregister); |
103 | |
104 | MODULE_LICENSE("GPL"); |
105 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
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v3.9