[mirror_ubuntu-bionic-kernel.git] / net / bridge / br_stp_bpdu.c

/*
 *	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 <linux/slab.h>
#include <linux/pkt_sched.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 int br_send_bpdu_finish(struct net *net, struct sock *sk,
			       struct sk_buff *skb)
{
	return dev_queue_xmit(skb);
}

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->priority = TC_PRIO_CONTROL;

	skb_reserve(skb, LLC_RESERVE);
	__skb_put_data(skb, 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);

	skb_reset_mac_header(skb);

	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT,
		dev_net(p->dev), NULL, skb, NULL, skb->dev,
		br_send_bpdu_finish);
}

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
 */
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;
	struct net_bridge *br;
	const unsigned char *buf;

	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;

	p = br_port_get_check_rcu(dev);
	if (!p)
		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 (!ether_addr_equal(dest, br->group_addr))
		goto out;

	if (p->flags & BR_BPDU_GUARD) {
		br_notice(br, "BPDU received on blocked port %u(%s)\n",
			  (unsigned int) p->port_no, p->dev->name);
		br_stp_disable_port(p);
		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);

		if (bpdu.message_age > bpdu.max_age) {
			if (net_ratelimit())
				br_notice(p->br,
					  "port %u config from %pM"
					  " (message_age %ul > max_age %ul)\n",
					  p->port_no,
					  eth_hdr(skb)->h_source,
					  bpdu.message_age, bpdu.max_age);
			goto out;
		}

		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 <buytenh@gnu.org>
	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>
5a0e3ad6	18	#include <linux/slab.h>
547b4e71	19	#include <linux/pkt_sched.h>
e730c155	20	#include <net/net_namespace.h>
12ac84c4	21	#include <net/llc.h>
cf0f02d0	22	#include <net/llc_pdu.h>
7c85fbf0	23	#include <net/stp.h>
4dc6d9cc	24	#include <asm/unaligned.h>
1da177e4 LT	25
	26	#include "br_private.h"
	27	#include "br_private_stp.h"
	28
18fdb2b2	29	#define STP_HZ 256
1da177e4	30
12ac84c4 SH	31	#define LLC_RESERVE sizeof(struct llc_pdu_un)
12ac84c4 SH	32
0c4b51f0 EB	33	static int br_send_bpdu_finish(struct net net, struct sock sk,
0c4b51f0 EB	34	struct sk_buff *skb)
1f19c578 EB	35	{
	36	return dev_queue_xmit(skb);
	37	}
	38
12ac84c4	39	static void br_send_bpdu(struct net_bridge_port *p,
9d6f229f	40	const unsigned char *data, int length)
1da177e4	41	{
1da177e4	42	struct sk_buff *skb;
1da177e4	43
12ac84c4 SH	44	skb = dev_alloc_skb(length+LLC_RESERVE);
12ac84c4 SH	45	if (!skb)
1da177e4	46	return;
1da177e4	47
12ac84c4	48	skb->dev = p->dev;
1da177e4	49	skb->protocol = htons(ETH_P_802_2);
547b4e71	50	skb->priority = TC_PRIO_CONTROL;
12ac84c4 SH	51
12ac84c4 SH	52	skb_reserve(skb, LLC_RESERVE);
de77b966	53	__skb_put_data(skb, data, length);
12ac84c4 SH	54
	55	llc_pdu_header_init(skb, LLC_PDU_TYPE_U, LLC_SAP_BSPAN,
	56	LLC_SAP_BSPAN, LLC_PDU_CMD);
	57	llc_pdu_init_as_ui_cmd(skb);
	58
	59	llc_mac_hdr_init(skb, p->dev->dev_addr, p->br->group_addr);
1da177e4	60
e6f26129 FW	61	skb_reset_mac_header(skb);
e6f26129 FW	62
29a26a56 EB	63	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT,
29a26a56 EB	64	dev_net(p->dev), NULL, skb, NULL, skb->dev,
1f19c578	65	br_send_bpdu_finish);
1da177e4 LT	66	}
1da177e4 LT	67
18fdb2b2	68	static inline void br_set_ticks(unsigned char *dest, int j)
1da177e4	69	{
18fdb2b2	70	unsigned long ticks = (STP_HZ * j)/ HZ;
1da177e4	71
d3e2ce3b	72	put_unaligned_be16(ticks, dest);
1da177e4 LT	73	}
1da177e4 LT	74
18fdb2b2	75	static inline int br_get_ticks(const unsigned char *src)
1da177e4	76	{
d3e2ce3b	77	unsigned long ticks = get_unaligned_be16(src);
18fdb2b2	78
172589cc	79	return DIV_ROUND_UP(ticks * HZ, STP_HZ);
1da177e4 LT	80	}
	81
	82	/* called under bridge lock */
	83	void br_send_config_bpdu(struct net_bridge_port p, struct br_config_bpdu bpdu)
	84	{
12ac84c4 SH	85	unsigned char buf[35];
12ac84c4 SH	86
9cde0708 SH	87	if (p->br->stp_enabled != BR_KERNEL_STP)
	88	return;
	89
12ac84c4 SH	90	buf[0] = 0;
	91	buf[1] = 0;
	92	buf[2] = 0;
	93	buf[3] = BPDU_TYPE_CONFIG;
	94	buf[4] = (bpdu->topology_change ? 0x01 : 0) \|
1da177e4	95	(bpdu->topology_change_ack ? 0x80 : 0);
12ac84c4 SH	96	buf[5] = bpdu->root.prio[0];
	97	buf[6] = bpdu->root.prio[1];
	98	buf[7] = bpdu->root.addr[0];
	99	buf[8] = bpdu->root.addr[1];
	100	buf[9] = bpdu->root.addr[2];
	101	buf[10] = bpdu->root.addr[3];
	102	buf[11] = bpdu->root.addr[4];
	103	buf[12] = bpdu->root.addr[5];
	104	buf[13] = (bpdu->root_path_cost >> 24) & 0xFF;
	105	buf[14] = (bpdu->root_path_cost >> 16) & 0xFF;
	106	buf[15] = (bpdu->root_path_cost >> 8) & 0xFF;
	107	buf[16] = bpdu->root_path_cost & 0xFF;
	108	buf[17] = bpdu->bridge_id.prio[0];
	109	buf[18] = bpdu->bridge_id.prio[1];
	110	buf[19] = bpdu->bridge_id.addr[0];
	111	buf[20] = bpdu->bridge_id.addr[1];
	112	buf[21] = bpdu->bridge_id.addr[2];
	113	buf[22] = bpdu->bridge_id.addr[3];
	114	buf[23] = bpdu->bridge_id.addr[4];
	115	buf[24] = bpdu->bridge_id.addr[5];
	116	buf[25] = (bpdu->port_id >> 8) & 0xFF;
	117	buf[26] = bpdu->port_id & 0xFF;
	118
	119	br_set_ticks(buf+27, bpdu->message_age);
	120	br_set_ticks(buf+29, bpdu->max_age);
	121	br_set_ticks(buf+31, bpdu->hello_time);
	122	br_set_ticks(buf+33, bpdu->forward_delay);
	123
	124	br_send_bpdu(p, buf, 35);
1da177e4 LT	125	}
	126
	127	/* called under bridge lock */
	128	void br_send_tcn_bpdu(struct net_bridge_port *p)
	129	{
12ac84c4 SH	130	unsigned char buf[4];
12ac84c4 SH	131
9cde0708 SH	132	if (p->br->stp_enabled != BR_KERNEL_STP)
	133	return;
	134
12ac84c4 SH	135	buf[0] = 0;
	136	buf[1] = 0;
	137	buf[2] = 0;
	138	buf[3] = BPDU_TYPE_TCN;
485c2967	139	br_send_bpdu(p, buf, 4);
1da177e4 LT	140	}
1da177e4 LT	141
cf0f02d0 SH	142	/*
	143	* Called from llc.
	144	*
eeaf61d8	145	* NO locks, but rcu_read_lock
cf0f02d0	146	*/
7c85fbf0 PM	147	void br_stp_rcv(const struct stp_proto proto, struct sk_buff skb,
7c85fbf0 PM	148	struct net_device *dev)
1da177e4	149	{
cf0f02d0	150	const unsigned char *dest = eth_hdr(skb)->h_dest;
f350a0a8	151	struct net_bridge_port *p;
b3f1be4b	152	struct net_bridge *br;
cf0f02d0	153	const unsigned char *buf;
1da177e4	154
cf0f02d0 SH	155	if (!pskb_may_pull(skb, 4))
	156	goto err;
	157
	158	/* compare of protocol id and version */
	159	buf = skb->data;
	160	if (buf[0] != 0 \|\| buf[1] != 0 \|\| buf[2] != 0)
	161	goto err;
b3f1be4b	162
859828c0	163	p = br_port_get_check_rcu(dev);
b5ed54e9	164	if (!p)
	165	goto err;
	166
cf0f02d0 SH	167	br = p->br;
cf0f02d0 SH	168	spin_lock(&br->lock);
b3f1be4b	169
9cde0708 SH	170	if (br->stp_enabled != BR_KERNEL_STP)
	171	goto out;
	172
	173	if (!(br->dev->flags & IFF_UP))
	174	goto out;
	175
	176	if (p->state == BR_STATE_DISABLED)
b3f1be4b	177	goto out;
85967bb4	178
9a7b6ef9	179	if (!ether_addr_equal(dest, br->group_addr))
b3f1be4b	180	goto out;
1da177e4	181
a2e01a65	182	if (p->flags & BR_BPDU_GUARD) {
	183	br_notice(br, "BPDU received on blocked port %u(%s)\n",
	184	(unsigned int) p->port_no, p->dev->name);
	185	br_stp_disable_port(p);
	186	goto out;
	187	}
	188
cf0f02d0	189	buf = skb_pull(skb, 3);
1da177e4	190
1da177e4 LT	191	if (buf[0] == BPDU_TYPE_CONFIG) {
	192	struct br_config_bpdu bpdu;
	193
	194	if (!pskb_may_pull(skb, 32))
cf0f02d0	195	goto out;
1da177e4 LT	196
	197	buf = skb->data;
	198	bpdu.topology_change = (buf[1] & 0x01) ? 1 : 0;
	199	bpdu.topology_change_ack = (buf[1] & 0x80) ? 1 : 0;
	200
	201	bpdu.root.prio[0] = buf[2];
	202	bpdu.root.prio[1] = buf[3];
	203	bpdu.root.addr[0] = buf[4];
	204	bpdu.root.addr[1] = buf[5];
	205	bpdu.root.addr[2] = buf[6];
	206	bpdu.root.addr[3] = buf[7];
	207	bpdu.root.addr[4] = buf[8];
	208	bpdu.root.addr[5] = buf[9];
	209	bpdu.root_path_cost =
	210	(buf[10] << 24) \|
	211	(buf[11] << 16) \|
	212	(buf[12] << 8) \|
	213	buf[13];
	214	bpdu.bridge_id.prio[0] = buf[14];
	215	bpdu.bridge_id.prio[1] = buf[15];
	216	bpdu.bridge_id.addr[0] = buf[16];
	217	bpdu.bridge_id.addr[1] = buf[17];
	218	bpdu.bridge_id.addr[2] = buf[18];
	219	bpdu.bridge_id.addr[3] = buf[19];
	220	bpdu.bridge_id.addr[4] = buf[20];
	221	bpdu.bridge_id.addr[5] = buf[21];
	222	bpdu.port_id = (buf[22] << 8) \| buf[23];
	223
	224	bpdu.message_age = br_get_ticks(buf+24);
	225	bpdu.max_age = br_get_ticks(buf+26);
	226	bpdu.hello_time = br_get_ticks(buf+28);
	227	bpdu.forward_delay = br_get_ticks(buf+30);
	228
0652cac2	229	if (bpdu.message_age > bpdu.max_age) {
	230	if (net_ratelimit())
	231	br_notice(p->br,
	232	"port %u config from %pM"
	233	" (message_age %ul > max_age %ul)\n",
	234	p->port_no,
	235	eth_hdr(skb)->h_source,
	236	bpdu.message_age, bpdu.max_age);
	237	goto out;
	238	}
	239
1da177e4	240	br_received_config_bpdu(p, &bpdu);
160d73b8	241	} else if (buf[0] == BPDU_TYPE_TCN) {
1da177e4 LT	242	br_received_tcn_bpdu(p);
	243	}
	244	out:
b3f1be4b	245	spin_unlock(&br->lock);
1da177e4 LT	246	err:
1da177e4 LT	247	kfree_skb(skb);
1da177e4	248	}