1 files changed, 102 insertions, 0 deletions

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 <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");