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