]>
Commit | Line | Data |
---|---|---|
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"); |