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-rw-r--r--net/802/stp.c101
1 files changed, 101 insertions, 0 deletions
diff --git a/net/802/stp.c b/net/802/stp.c
new file mode 100644
index 000000000..d550d9f88
--- /dev/null
+++ b/net/802/stp.c
@@ -0,0 +1,101 @@
+// 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");