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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
25static const struct stp_proto __rcu *garp_protos[GARP_ADDR_RANGE + 1] __read_mostly;
26static const struct stp_proto __rcu *stp_proto __read_mostly;
27
28static struct llc_sap *sap __read_mostly;
29static unsigned int sap_registered;
30static DEFINE_MUTEX(stp_proto_mutex);
31
32/* Called under rcu_read_lock from LLC */
33static 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
60err:
61 kfree_skb(skb);
62 return 0;
63}
64
65int 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);
82out:
83 mutex_unlock(&stp_proto_mutex);
84 return err;
85}
86EXPORT_SYMBOL_GPL(stp_proto_register);
87
88void 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}
102EXPORT_SYMBOL_GPL(stp_proto_unregister);
103
104MODULE_LICENSE("GPL");
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
25static const struct stp_proto __rcu *garp_protos[GARP_ADDR_RANGE + 1] __read_mostly;
26static const struct stp_proto __rcu *stp_proto __read_mostly;
27
28static struct llc_sap *sap __read_mostly;
29static unsigned int sap_registered;
30static DEFINE_MUTEX(stp_proto_mutex);
31
32/* Called under rcu_read_lock from LLC */
33static 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
60err:
61 kfree_skb(skb);
62 return 0;
63}
64
65int 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);
82out:
83 mutex_unlock(&stp_proto_mutex);
84 return err;
85}
86EXPORT_SYMBOL_GPL(stp_proto_register);
87
88void 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}
102EXPORT_SYMBOL_GPL(stp_proto_unregister);
103
104MODULE_LICENSE("GPL");