[linux.git] / net / bridge / br_stp_bpdu.c

/*
 *	Spanning tree protocol; BPDU handling
 *	Linux ethernet bridge
 *
 *	Authors:
 *	Lennert Buytenhek		<[email protected]>
 *
 *	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);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Spanning tree protocol; BPDU handling
	3	* Linux ethernet bridge
	4	*
	5	* Authors:
	6	* Lennert Buytenhek <[email protected]>
	7	*
1da177e4 LT	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public License
	10	* as published by the Free Software Foundation; either version
	11	* 2 of the License, or (at your option) any later version.
	12	*/
	13
	14	#include <linux/kernel.h>
	15	#include <linux/netfilter_bridge.h>
cf0f02d0 SH	16	#include <linux/etherdevice.h>
cf0f02d0 SH	17	#include <linux/llc.h>
e730c155	18	#include <net/net_namespace.h>
12ac84c4	19	#include <net/llc.h>
cf0f02d0	20	#include <net/llc_pdu.h>
7c85fbf0	21	#include <net/stp.h>
4dc6d9cc	22	#include <asm/unaligned.h>
1da177e4 LT	23
	24	#include "br_private.h"
	25	#include "br_private_stp.h"
	26
18fdb2b2	27	#define STP_HZ 256
1da177e4	28
12ac84c4 SH	29	#define LLC_RESERVE sizeof(struct llc_pdu_un)
	30
	31	static void br_send_bpdu(struct net_bridge_port *p,
9d6f229f	32	const unsigned char *data, int length)
1da177e4	33	{
1da177e4	34	struct sk_buff *skb;
1da177e4	35
12ac84c4 SH	36	skb = dev_alloc_skb(length+LLC_RESERVE);
12ac84c4 SH	37	if (!skb)
1da177e4	38	return;
1da177e4	39
12ac84c4	40	skb->dev = p->dev;
1da177e4	41	skb->protocol = htons(ETH_P_802_2);
12ac84c4 SH	42
	43	skb_reserve(skb, LLC_RESERVE);
	44	memcpy(__skb_put(skb, length), data, length);
	45
	46	llc_pdu_header_init(skb, LLC_PDU_TYPE_U, LLC_SAP_BSPAN,
	47	LLC_SAP_BSPAN, LLC_PDU_CMD);
	48	llc_pdu_init_as_ui_cmd(skb);
	49
	50	llc_mac_hdr_init(skb, p->dev->dev_addr, p->br->group_addr);
1da177e4 LT	51
	52	NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
	53	dev_queue_xmit);
	54	}
	55
18fdb2b2	56	static inline void br_set_ticks(unsigned char *dest, int j)
1da177e4	57	{
18fdb2b2	58	unsigned long ticks = (STP_HZ * j)/ HZ;
1da177e4	59
d3e2ce3b	60	put_unaligned_be16(ticks, dest);
1da177e4 LT	61	}
1da177e4 LT	62
18fdb2b2	63	static inline int br_get_ticks(const unsigned char *src)
1da177e4	64	{
d3e2ce3b	65	unsigned long ticks = get_unaligned_be16(src);
18fdb2b2	66
172589cc	67	return DIV_ROUND_UP(ticks * HZ, STP_HZ);
1da177e4 LT	68	}
	69
	70	/* called under bridge lock */
	71	void br_send_config_bpdu(struct net_bridge_port p, struct br_config_bpdu bpdu)
	72	{
12ac84c4 SH	73	unsigned char buf[35];
12ac84c4 SH	74
9cde0708 SH	75	if (p->br->stp_enabled != BR_KERNEL_STP)
	76	return;
	77
12ac84c4 SH	78	buf[0] = 0;
	79	buf[1] = 0;
	80	buf[2] = 0;
	81	buf[3] = BPDU_TYPE_CONFIG;
	82	buf[4] = (bpdu->topology_change ? 0x01 : 0) \|
1da177e4	83	(bpdu->topology_change_ack ? 0x80 : 0);
12ac84c4 SH	84	buf[5] = bpdu->root.prio[0];
	85	buf[6] = bpdu->root.prio[1];
	86	buf[7] = bpdu->root.addr[0];
	87	buf[8] = bpdu->root.addr[1];
	88	buf[9] = bpdu->root.addr[2];
	89	buf[10] = bpdu->root.addr[3];
	90	buf[11] = bpdu->root.addr[4];
	91	buf[12] = bpdu->root.addr[5];
	92	buf[13] = (bpdu->root_path_cost >> 24) & 0xFF;
	93	buf[14] = (bpdu->root_path_cost >> 16) & 0xFF;
	94	buf[15] = (bpdu->root_path_cost >> 8) & 0xFF;
	95	buf[16] = bpdu->root_path_cost & 0xFF;
	96	buf[17] = bpdu->bridge_id.prio[0];
	97	buf[18] = bpdu->bridge_id.prio[1];
	98	buf[19] = bpdu->bridge_id.addr[0];
	99	buf[20] = bpdu->bridge_id.addr[1];
	100	buf[21] = bpdu->bridge_id.addr[2];
	101	buf[22] = bpdu->bridge_id.addr[3];
	102	buf[23] = bpdu->bridge_id.addr[4];
	103	buf[24] = bpdu->bridge_id.addr[5];
	104	buf[25] = (bpdu->port_id >> 8) & 0xFF;
	105	buf[26] = bpdu->port_id & 0xFF;
	106
	107	br_set_ticks(buf+27, bpdu->message_age);
	108	br_set_ticks(buf+29, bpdu->max_age);
	109	br_set_ticks(buf+31, bpdu->hello_time);
	110	br_set_ticks(buf+33, bpdu->forward_delay);
	111
	112	br_send_bpdu(p, buf, 35);
1da177e4 LT	113	}
	114
	115	/* called under bridge lock */
	116	void br_send_tcn_bpdu(struct net_bridge_port *p)
	117	{
12ac84c4 SH	118	unsigned char buf[4];
12ac84c4 SH	119
9cde0708 SH	120	if (p->br->stp_enabled != BR_KERNEL_STP)
	121	return;
	122
12ac84c4 SH	123	buf[0] = 0;
	124	buf[1] = 0;
	125	buf[2] = 0;
	126	buf[3] = BPDU_TYPE_TCN;
485c2967	127	br_send_bpdu(p, buf, 4);
1da177e4 LT	128	}
1da177e4 LT	129
cf0f02d0 SH	130	/*
	131	* Called from llc.
	132	*
	133	* NO locks, but rcu_read_lock (preempt_disabled)
	134	*/
7c85fbf0 PM	135	void br_stp_rcv(const struct stp_proto proto, struct sk_buff skb,
7c85fbf0 PM	136	struct net_device *dev)
1da177e4	137	{
cf0f02d0 SH	138	const unsigned char *dest = eth_hdr(skb)->h_dest;
cf0f02d0 SH	139	struct net_bridge_port *p = rcu_dereference(dev->br_port);
b3f1be4b	140	struct net_bridge *br;
cf0f02d0	141	const unsigned char *buf;
1da177e4	142
b3f1be4b SH	143	if (!p)
	144	goto err;
	145
cf0f02d0 SH	146	if (!pskb_may_pull(skb, 4))
	147	goto err;
	148
	149	/* compare of protocol id and version */
	150	buf = skb->data;
	151	if (buf[0] != 0 \|\| buf[1] != 0 \|\| buf[2] != 0)
	152	goto err;
b3f1be4b	153
cf0f02d0 SH	154	br = p->br;
cf0f02d0 SH	155	spin_lock(&br->lock);
b3f1be4b	156
9cde0708 SH	157	if (br->stp_enabled != BR_KERNEL_STP)
	158	goto out;
	159
	160	if (!(br->dev->flags & IFF_UP))
	161	goto out;
	162
	163	if (p->state == BR_STATE_DISABLED)
b3f1be4b	164	goto out;
85967bb4	165
fda93d92	166	if (compare_ether_addr(dest, br->group_addr) != 0)
b3f1be4b	167	goto out;
1da177e4	168
cf0f02d0	169	buf = skb_pull(skb, 3);
1da177e4	170
1da177e4 LT	171	if (buf[0] == BPDU_TYPE_CONFIG) {
	172	struct br_config_bpdu bpdu;
	173
	174	if (!pskb_may_pull(skb, 32))
cf0f02d0	175	goto out;
1da177e4 LT	176
	177	buf = skb->data;
	178	bpdu.topology_change = (buf[1] & 0x01) ? 1 : 0;
	179	bpdu.topology_change_ack = (buf[1] & 0x80) ? 1 : 0;
	180
	181	bpdu.root.prio[0] = buf[2];
	182	bpdu.root.prio[1] = buf[3];
	183	bpdu.root.addr[0] = buf[4];
	184	bpdu.root.addr[1] = buf[5];
	185	bpdu.root.addr[2] = buf[6];
	186	bpdu.root.addr[3] = buf[7];
	187	bpdu.root.addr[4] = buf[8];
	188	bpdu.root.addr[5] = buf[9];
	189	bpdu.root_path_cost =
	190	(buf[10] << 24) \|
	191	(buf[11] << 16) \|
	192	(buf[12] << 8) \|
	193	buf[13];
	194	bpdu.bridge_id.prio[0] = buf[14];
	195	bpdu.bridge_id.prio[1] = buf[15];
	196	bpdu.bridge_id.addr[0] = buf[16];
	197	bpdu.bridge_id.addr[1] = buf[17];
	198	bpdu.bridge_id.addr[2] = buf[18];
	199	bpdu.bridge_id.addr[3] = buf[19];
	200	bpdu.bridge_id.addr[4] = buf[20];
	201	bpdu.bridge_id.addr[5] = buf[21];
	202	bpdu.port_id = (buf[22] << 8) \| buf[23];
	203
	204	bpdu.message_age = br_get_ticks(buf+24);
	205	bpdu.max_age = br_get_ticks(buf+26);
	206	bpdu.hello_time = br_get_ticks(buf+28);
	207	bpdu.forward_delay = br_get_ticks(buf+30);
	208
	209	br_received_config_bpdu(p, &bpdu);
	210	}
	211
	212	else if (buf[0] == BPDU_TYPE_TCN) {
	213	br_received_tcn_bpdu(p);
	214	}
	215	out:
b3f1be4b	216	spin_unlock(&br->lock);
1da177e4 LT	217	err:
1da177e4 LT	218	kfree_skb(skb);
1da177e4	219	}