/net/802/stp.c
http://github.com/mirrors/linux · C · 101 lines · 79 code · 14 blank · 8 comment · 15 complexity · 048b6a03d1f0a71504adbe0a8a257ceb MD5 · raw file
- // 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");