| Patrick McHardy | a19800d | 2008-07-05 21:25:39 -0700 | [diff] [blame] | 1 | /* |
| 2 | * STP SAP demux |
| 3 | * |
| 4 | * Copyright (c) 2008 Patrick McHardy <kaber@trash.net> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * version 2 as published by the Free Software Foundation. |
| 9 | */ |
| 10 | #include <linux/mutex.h> |
| 11 | #include <linux/skbuff.h> |
| 12 | #include <linux/etherdevice.h> |
| 13 | #include <linux/llc.h> |
| 14 | #include <net/llc.h> |
| 15 | #include <net/llc_pdu.h> |
| 16 | #include <net/stp.h> |
| 17 | |
| 18 | /* 01:80:c2:00:00:20 - 01:80:c2:00:00:2F */ |
| 19 | #define GARP_ADDR_MIN 0x20 |
| 20 | #define GARP_ADDR_MAX 0x2F |
| 21 | #define GARP_ADDR_RANGE (GARP_ADDR_MAX - GARP_ADDR_MIN) |
| 22 | |
| 23 | static const struct stp_proto *garp_protos[GARP_ADDR_RANGE + 1] __read_mostly; |
| 24 | static const struct stp_proto *stp_proto __read_mostly; |
| 25 | |
| 26 | static struct llc_sap *sap __read_mostly; |
| 27 | static unsigned int sap_registered; |
| 28 | static DEFINE_MUTEX(stp_proto_mutex); |
| 29 | |
| 30 | /* Called under rcu_read_lock from LLC */ |
| 31 | static int stp_pdu_rcv(struct sk_buff *skb, struct net_device *dev, |
| 32 | struct packet_type *pt, struct net_device *orig_dev) |
| 33 | { |
| 34 | const struct ethhdr *eh = eth_hdr(skb); |
| 35 | const struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb); |
| 36 | const struct stp_proto *proto; |
| 37 | |
| 38 | if (pdu->ssap != LLC_SAP_BSPAN || |
| 39 | pdu->dsap != LLC_SAP_BSPAN || |
| 40 | pdu->ctrl_1 != LLC_PDU_TYPE_U) |
| 41 | goto err; |
| 42 | |
| 43 | if (eh->h_dest[5] >= GARP_ADDR_MIN && eh->h_dest[5] <= GARP_ADDR_MAX) { |
| 44 | proto = rcu_dereference(garp_protos[eh->h_dest[5] - |
| 45 | GARP_ADDR_MIN]); |
| 46 | if (proto && |
| 47 | compare_ether_addr(eh->h_dest, proto->group_address)) |
| 48 | goto err; |
| 49 | } else |
| 50 | proto = rcu_dereference(stp_proto); |
| 51 | |
| 52 | if (!proto) |
| 53 | goto err; |
| 54 | |
| 55 | proto->rcv(proto, skb, dev); |
| 56 | return 0; |
| 57 | |
| 58 | err: |
| 59 | kfree_skb(skb); |
| 60 | return 0; |
| 61 | } |
| 62 | |
| 63 | int stp_proto_register(const struct stp_proto *proto) |
| 64 | { |
| 65 | int err = 0; |
| 66 | |
| 67 | mutex_lock(&stp_proto_mutex); |
| 68 | if (sap_registered++ == 0) { |
| 69 | sap = llc_sap_open(LLC_SAP_BSPAN, stp_pdu_rcv); |
| 70 | if (!sap) { |
| 71 | err = -ENOMEM; |
| 72 | goto out; |
| 73 | } |
| 74 | } |
| 75 | if (is_zero_ether_addr(proto->group_address)) |
| 76 | rcu_assign_pointer(stp_proto, proto); |
| 77 | else |
| 78 | rcu_assign_pointer(garp_protos[proto->group_address[5] - |
| 79 | GARP_ADDR_MIN], proto); |
| 80 | out: |
| 81 | mutex_unlock(&stp_proto_mutex); |
| 82 | return err; |
| 83 | } |
| 84 | EXPORT_SYMBOL_GPL(stp_proto_register); |
| 85 | |
| 86 | void stp_proto_unregister(const struct stp_proto *proto) |
| 87 | { |
| 88 | mutex_lock(&stp_proto_mutex); |
| 89 | if (is_zero_ether_addr(proto->group_address)) |
| 90 | rcu_assign_pointer(stp_proto, NULL); |
| 91 | else |
| 92 | rcu_assign_pointer(garp_protos[proto->group_address[5] - |
| 93 | GARP_ADDR_MIN], NULL); |
| 94 | synchronize_rcu(); |
| 95 | |
| 96 | if (--sap_registered == 0) |
| 97 | llc_sap_put(sap); |
| 98 | mutex_unlock(&stp_proto_mutex); |
| 99 | } |
| 100 | EXPORT_SYMBOL_GPL(stp_proto_unregister); |
| 101 | |
| 102 | MODULE_LICENSE("GPL"); |