From a19800d704177caaa5874baf5819307c5b7d5e4f Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Sat, 5 Jul 2008 21:25:39 -0700 Subject: 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: Patrick McHardy Signed-off-by: David S. Miller --- net/802/stp.c | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 net/802/stp.c (limited to 'net/802/stp.c') diff --git a/net/802/stp.c b/net/802/stp.c new file mode 100644 index 000000000000..0b7a24452d11 --- /dev/null +++ b/net/802/stp.c @@ -0,0 +1,102 @@ +/* + * STP SAP demux + * + * Copyright (c) 2008 Patrick McHardy + * + * 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 +#include +#include +#include +#include +#include +#include + +/* 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"); -- cgit v1.2.3