1 files changed, 219 insertions, 0 deletions
diff --git a/net/bridge/br_stp_bpdu.c b/net/bridge/br_stp_bpdu.c
new file mode 100644
index 0000000..81ae40b
--- /dev/null
+++ b/net/bridge/br_stp_bpdu.c
@@ -0,0 +1,219 @@
+/*
+ *	Spanning tree protocol; BPDU handling
+ *	Linux ethernet bridge
+ *
+ *	Authors:
+ *	Lennert Buytenhek		<buytenh@gnu.org>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/netfilter_bridge.h>
+#include <linux/etherdevice.h>
+#include <linux/llc.h>
+#include <net/net_namespace.h>
+#include <net/llc.h>
+#include <net/llc_pdu.h>
+#include <net/stp.h>
+#include <asm/unaligned.h>
+
+#include "br_private.h"
+#include "br_private_stp.h"
+
+#define STP_HZ		256
+
+#define LLC_RESERVE sizeof(struct llc_pdu_un)
+
+static void br_send_bpdu(struct net_bridge_port *p,
+			 const unsigned char *data, int length)
+{
+	struct sk_buff *skb;
+
+	skb = dev_alloc_skb(length+LLC_RESERVE);
+	if (!skb)
+		return;
+
+	skb->dev = p->dev;
+	skb->protocol = htons(ETH_P_802_2);
+
+	skb_reserve(skb, LLC_RESERVE);
+	memcpy(__skb_put(skb, length), data, length);
+
+	llc_pdu_header_init(skb, LLC_PDU_TYPE_U, LLC_SAP_BSPAN,
+			    LLC_SAP_BSPAN, LLC_PDU_CMD);
+	llc_pdu_init_as_ui_cmd(skb);
+
+	llc_mac_hdr_init(skb, p->dev->dev_addr, p->br->group_addr);
+
+	NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
+		dev_queue_xmit);
+}
+
+static inline void br_set_ticks(unsigned char *dest, int j)
+{
+	unsigned long ticks = (STP_HZ * j)/ HZ;
+
+	put_unaligned_be16(ticks, dest);
+}
+
+static inline int br_get_ticks(const unsigned char *src)
+{
+	unsigned long ticks = get_unaligned_be16(src);
+
+	return DIV_ROUND_UP(ticks * HZ, STP_HZ);
+}
+
+/* called under bridge lock */
+void br_send_config_bpdu(struct net_bridge_port *p, struct br_config_bpdu *bpdu)
+{
+	unsigned char buf[35];
+
+	if (p->br->stp_enabled != BR_KERNEL_STP)
+		return;
+
+	buf[0] = 0;
+	buf[1] = 0;
+	buf[2] = 0;
+	buf[3] = BPDU_TYPE_CONFIG;
+	buf[4] = (bpdu->topology_change ? 0x01 : 0) |
+		(bpdu->topology_change_ack ? 0x80 : 0);
+	buf[5] = bpdu->root.prio[0];
+	buf[6] = bpdu->root.prio[1];
+	buf[7] = bpdu->root.addr[0];
+	buf[8] = bpdu->root.addr[1];
+	buf[9] = bpdu->root.addr[2];
+	buf[10] = bpdu->root.addr[3];
+	buf[11] = bpdu->root.addr[4];
+	buf[12] = bpdu->root.addr[5];
+	buf[13] = (bpdu->root_path_cost >> 24) & 0xFF;
+	buf[14] = (bpdu->root_path_cost >> 16) & 0xFF;
+	buf[15] = (bpdu->root_path_cost >> 8) & 0xFF;
+	buf[16] = bpdu->root_path_cost & 0xFF;
+	buf[17] = bpdu->bridge_id.prio[0];
+	buf[18] = bpdu->bridge_id.prio[1];
+	buf[19] = bpdu->bridge_id.addr[0];
+	buf[20] = bpdu->bridge_id.addr[1];
+	buf[21] = bpdu->bridge_id.addr[2];
+	buf[22] = bpdu->bridge_id.addr[3];
+	buf[23] = bpdu->bridge_id.addr[4];
+	buf[24] = bpdu->bridge_id.addr[5];
+	buf[25] = (bpdu->port_id >> 8) & 0xFF;
+	buf[26] = bpdu->port_id & 0xFF;
+
+	br_set_ticks(buf+27, bpdu->message_age);
+	br_set_ticks(buf+29, bpdu->max_age);
+	br_set_ticks(buf+31, bpdu->hello_time);
+	br_set_ticks(buf+33, bpdu->forward_delay);
+
+	br_send_bpdu(p, buf, 35);
+}
+
+/* called under bridge lock */
+void br_send_tcn_bpdu(struct net_bridge_port *p)
+{
+	unsigned char buf[4];
+
+	if (p->br->stp_enabled != BR_KERNEL_STP)
+		return;
+
+	buf[0] = 0;
+	buf[1] = 0;
+	buf[2] = 0;
+	buf[3] = BPDU_TYPE_TCN;
+	br_send_bpdu(p, buf, 4);
+}
+
+/*
+ * Called from llc.
+ *
+ * NO locks, but rcu_read_lock (preempt_disabled)
+ */
+void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb,
+		struct net_device *dev)
+{
+	const unsigned char *dest = eth_hdr(skb)->h_dest;
+	struct net_bridge_port *p = rcu_dereference(dev->br_port);
+	struct net_bridge *br;
+	const unsigned char *buf;
+
+	if (!p)
+		goto err;
+
+	if (!pskb_may_pull(skb, 4))
+		goto err;
+
+	/* compare of protocol id and version */
+	buf = skb->data;
+	if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0)
+		goto err;
+
+	br = p->br;
+	spin_lock(&br->lock);
+
+	if (br->stp_enabled != BR_KERNEL_STP)
+		goto out;
+
+	if (!(br->dev->flags & IFF_UP))
+		goto out;
+
+	if (p->state == BR_STATE_DISABLED)
+		goto out;
+
+	if (compare_ether_addr(dest, br->group_addr) != 0)
+		goto out;
+
+	buf = skb_pull(skb, 3);
+
+	if (buf[0] == BPDU_TYPE_CONFIG) {
+		struct br_config_bpdu bpdu;
+
+		if (!pskb_may_pull(skb, 32))
+			goto out;
+
+		buf = skb->data;
+		bpdu.topology_change = (buf[1] & 0x01) ? 1 : 0;
+		bpdu.topology_change_ack = (buf[1] & 0x80) ? 1 : 0;
+
+		bpdu.root.prio[0] = buf[2];
+		bpdu.root.prio[1] = buf[3];
+		bpdu.root.addr[0] = buf[4];
+		bpdu.root.addr[1] = buf[5];
+		bpdu.root.addr[2] = buf[6];
+		bpdu.root.addr[3] = buf[7];
+		bpdu.root.addr[4] = buf[8];
+		bpdu.root.addr[5] = buf[9];
+		bpdu.root_path_cost =
+			(buf[10] << 24) |
+			(buf[11] << 16) |
+			(buf[12] << 8) |
+			buf[13];
+		bpdu.bridge_id.prio[0] = buf[14];
+		bpdu.bridge_id.prio[1] = buf[15];
+		bpdu.bridge_id.addr[0] = buf[16];
+		bpdu.bridge_id.addr[1] = buf[17];
+		bpdu.bridge_id.addr[2] = buf[18];
+		bpdu.bridge_id.addr[3] = buf[19];
+		bpdu.bridge_id.addr[4] = buf[20];
+		bpdu.bridge_id.addr[5] = buf[21];
+		bpdu.port_id = (buf[22] << 8) | buf[23];
+
+		bpdu.message_age = br_get_ticks(buf+24);
+		bpdu.max_age = br_get_ticks(buf+26);
+		bpdu.hello_time = br_get_ticks(buf+28);
+		bpdu.forward_delay = br_get_ticks(buf+30);
+
+		br_received_config_bpdu(p, &bpdu);
+	}
+
+	else if (buf[0] == BPDU_TYPE_TCN) {
+		br_received_tcn_bpdu(p);
+	}
+ out:
+	spin_unlock(&br->lock);
+ err:
+	kfree_skb(skb);
+}