102 lines
2.5 KiB
C
102 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* STP SAP demux
|
|
*
|
|
* Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
|
|
*/
|
|
#include <linux/mutex.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/etherdevice.h>
|
|
#include <linux/llc.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/module.h>
|
|
#include <net/llc.h>
|
|
#include <net/llc_pdu.h>
|
|
#include <net/stp.h>
|
|
|
|
/* 01:80:c2:00:00:20 - 01:80:c2:00:00:2F */
|
|
#define GARP_ADDR_MIN 0x20
|
|
#define GARP_ADDR_MAX 0x2F
|
|
#define GARP_ADDR_RANGE (GARP_ADDR_MAX - GARP_ADDR_MIN)
|
|
|
|
static const struct stp_proto __rcu *garp_protos[GARP_ADDR_RANGE + 1] __read_mostly;
|
|
static const struct stp_proto __rcu *stp_proto __read_mostly;
|
|
|
|
static struct llc_sap *sap __read_mostly;
|
|
static unsigned int sap_registered;
|
|
static DEFINE_MUTEX(stp_proto_mutex);
|
|
|
|
/* Called under rcu_read_lock from LLC */
|
|
static int stp_pdu_rcv(struct sk_buff *skb, struct net_device *dev,
|
|
struct packet_type *pt, struct net_device *orig_dev)
|
|
{
|
|
const struct ethhdr *eh = eth_hdr(skb);
|
|
const struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
|
|
const struct stp_proto *proto;
|
|
|
|
if (pdu->ssap != LLC_SAP_BSPAN ||
|
|
pdu->dsap != LLC_SAP_BSPAN ||
|
|
pdu->ctrl_1 != LLC_PDU_TYPE_U)
|
|
goto err;
|
|
|
|
if (eh->h_dest[5] >= GARP_ADDR_MIN && eh->h_dest[5] <= GARP_ADDR_MAX) {
|
|
proto = rcu_dereference(garp_protos[eh->h_dest[5] -
|
|
GARP_ADDR_MIN]);
|
|
if (proto &&
|
|
!ether_addr_equal(eh->h_dest, proto->group_address))
|
|
goto err;
|
|
} else
|
|
proto = rcu_dereference(stp_proto);
|
|
|
|
if (!proto)
|
|
goto err;
|
|
|
|
proto->rcv(proto, skb, dev);
|
|
return 0;
|
|
|
|
err:
|
|
kfree_skb(skb);
|
|
return 0;
|
|
}
|
|
|
|
int stp_proto_register(const struct stp_proto *proto)
|
|
{
|
|
int err = 0;
|
|
|
|
mutex_lock(&stp_proto_mutex);
|
|
if (sap_registered++ == 0) {
|
|
sap = llc_sap_open(LLC_SAP_BSPAN, stp_pdu_rcv);
|
|
if (!sap) {
|
|
err = -ENOMEM;
|
|
goto out;
|
|
}
|
|
}
|
|
if (is_zero_ether_addr(proto->group_address))
|
|
rcu_assign_pointer(stp_proto, proto);
|
|
else
|
|
rcu_assign_pointer(garp_protos[proto->group_address[5] -
|
|
GARP_ADDR_MIN], proto);
|
|
out:
|
|
mutex_unlock(&stp_proto_mutex);
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(stp_proto_register);
|
|
|
|
void stp_proto_unregister(const struct stp_proto *proto)
|
|
{
|
|
mutex_lock(&stp_proto_mutex);
|
|
if (is_zero_ether_addr(proto->group_address))
|
|
RCU_INIT_POINTER(stp_proto, NULL);
|
|
else
|
|
RCU_INIT_POINTER(garp_protos[proto->group_address[5] -
|
|
GARP_ADDR_MIN], NULL);
|
|
synchronize_rcu();
|
|
|
|
if (--sap_registered == 0)
|
|
llc_sap_put(sap);
|
|
mutex_unlock(&stp_proto_mutex);
|
|
}
|
|
EXPORT_SYMBOL_GPL(stp_proto_unregister);
|
|
|
|
MODULE_LICENSE("GPL");
|