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Commit a19800d7 authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

net: Add STP demux layer 



Add small STP demux layer for demuxing STP PDUs based on MAC address.
This is needed to run both GARP and STP in parallel (or even load the
modules) since both use LLC_SAP_BSPAN.

Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ef28d1a2

include/net/stp.h

0 → 100644
+14 −0
Original line number Diff line number Diff line 
#ifndef _NET_STP_H

#define _NET_STP_H



struct stp_proto {

	unsigned char	group_address[ETH_ALEN];

	void		(*rcv)(const struct stp_proto *, struct sk_buff *,

			       struct net_device *);

	void		*data;

};



extern int stp_proto_register(const struct stp_proto *proto);

extern void stp_proto_unregister(const struct stp_proto *proto);



#endif /* _NET_STP_H */

net/802/Kconfig

0 → 100644
+3 −0
Original line number Diff line number Diff line 
config STP

	tristate

	select LLC

net/802/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -10,3 +10,4 @@ obj-$(CONFIG_FDDI) += fddi.o 
obj-$(CONFIG_HIPPI)	+=                 hippi.o

obj-$(CONFIG_IPX)	+= p8022.o psnap.o p8023.o

obj-$(CONFIG_ATALK)	+= p8022.o psnap.o

obj-$(CONFIG_STP)	+= stp.o

net/802/stp.c

0 → 100644
+102 −0
Original line number Diff line number Diff line 
/*

 *	STP SAP demux

 *

 *	Copyright (c) 2008 Patrick McHardy <kaber@trash.net>

 *

 *	This program is free software; you can redistribute it and/or

 *	modify it under the terms of the GNU General Public License

 *	version 2 as published by the Free Software Foundation.

 */

#include <linux/mutex.h>

#include <linux/skbuff.h>

#include <linux/etherdevice.h>

#include <linux/llc.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 *garp_protos[GARP_ADDR_RANGE + 1] __read_mostly;

static const struct stp_proto *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 &&

		    compare_ether_addr(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_assign_pointer(stp_proto, NULL);

	else

		rcu_assign_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");

net/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -181,6 +181,7 @@ source "net/dccp/Kconfig" 
source "net/sctp/Kconfig"

source "net/tipc/Kconfig"

source "net/atm/Kconfig"

source "net/802/Kconfig"

source "net/bridge/Kconfig"

source "net/8021q/Kconfig"

source "net/decnet/Kconfig"