[mirror_ubuntu-zesty-kernel.git] / net / hsr / hsr_framereg.c

/* Copyright 2011-2014 Autronica Fire and Security AS
 *
 * 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.
 *
 * Author(s):
 *	2011-2014 Arvid Brodin, arvid.brodin@alten.se
 *
 * The HSR spec says never to forward the same frame twice on the same
 * interface. A frame is identified by its source MAC address and its HSR
 * sequence number. This code keeps track of senders and their sequence numbers
 * to allow filtering of duplicate frames, and to detect HSR ring errors.
 */

#include <linux/if_ether.h>
#include <linux/etherdevice.h>
#include <linux/slab.h>
#include <linux/rculist.h>
#include "hsr_main.h"
#include "hsr_framereg.h"
#include "hsr_netlink.h"


struct hsr_node {
	struct list_head	mac_list;
	unsigned char		MacAddressA[ETH_ALEN];
	unsigned char		MacAddressB[ETH_ALEN];
	/* Local slave through which AddrB frames are received from this node */
	enum hsr_port_type	AddrB_port;
	unsigned long		time_in[HSR_PT_PORTS];
	bool			time_in_stale[HSR_PT_PORTS];
	u16			seq_out[HSR_PT_PORTS];
	struct rcu_head		rcu_head;
};


/*	TODO: use hash lists for mac addresses (linux/jhash.h)?    */


/* seq_nr_after(a, b) - return true if a is after (higher in sequence than) b,
 * false otherwise.
 */
static bool seq_nr_after(u16 a, u16 b)
{
	/* Remove inconsistency where
	 * seq_nr_after(a, b) == seq_nr_before(a, b)
	 */
	if ((int) b - a == 32768)
		return false;

	return (((s16) (b - a)) < 0);
}
#define seq_nr_before(a, b)		seq_nr_after((b), (a))
#define seq_nr_after_or_eq(a, b)	(!seq_nr_before((a), (b)))
#define seq_nr_before_or_eq(a, b)	(!seq_nr_after((a), (b)))


bool hsr_addr_is_self(struct hsr_priv *hsr, unsigned char *addr)
{
	struct hsr_node *node;

	node = list_first_or_null_rcu(&hsr->self_node_db, struct hsr_node,
				      mac_list);
	if (!node) {
		WARN_ONCE(1, "HSR: No self node\n");
		return false;
	}

	if (ether_addr_equal(addr, node->MacAddressA))
		return true;
	if (ether_addr_equal(addr, node->MacAddressB))
		return true;

	return false;
}

/* Search for mac entry. Caller must hold rcu read lock.
 */
static struct hsr_node *find_node_by_AddrA(struct list_head *node_db,
					   const unsigned char addr[ETH_ALEN])
{
	struct hsr_node *node;

	list_for_each_entry_rcu(node, node_db, mac_list) {
		if (ether_addr_equal(node->MacAddressA, addr))
			return node;
	}

	return NULL;
}


/* Helper for device init; the self_node_db is used in hsr_rcv() to recognize
 * frames from self that's been looped over the HSR ring.
 */
int hsr_create_self_node(struct list_head *self_node_db,
			 unsigned char addr_a[ETH_ALEN],
			 unsigned char addr_b[ETH_ALEN])
{
	struct hsr_node *node, *oldnode;

	node = kmalloc(sizeof(*node), GFP_KERNEL);
	if (!node)
		return -ENOMEM;

	ether_addr_copy(node->MacAddressA, addr_a);
	ether_addr_copy(node->MacAddressB, addr_b);

	rcu_read_lock();
	oldnode = list_first_or_null_rcu(self_node_db,
						struct hsr_node, mac_list);
	if (oldnode) {
		list_replace_rcu(&oldnode->mac_list, &node->mac_list);
		rcu_read_unlock();
		synchronize_rcu();
		kfree(oldnode);
	} else {
		rcu_read_unlock();
		list_add_tail_rcu(&node->mac_list, self_node_db);
	}

	return 0;
}


/* Allocate an hsr_node and add it to node_db. 'addr' is the node's AddressA;
 * seq_out is used to initialize filtering of outgoing duplicate frames
 * originating from the newly added node.
 */
struct hsr_node *hsr_add_node(struct list_head *node_db, unsigned char addr[],
			      u16 seq_out)
{
	struct hsr_node *node;
	unsigned long now;
	int i;

	node = kzalloc(sizeof(*node), GFP_ATOMIC);
	if (!node)
		return NULL;

	ether_addr_copy(node->MacAddressA, addr);

	/* We are only interested in time diffs here, so use current jiffies
	 * as initialization. (0 could trigger an spurious ring error warning).
	 */
	now = jiffies;
	for (i = 0; i < HSR_PT_PORTS; i++)
		node->time_in[i] = now;
	for (i = 0; i < HSR_PT_PORTS; i++)
		node->seq_out[i] = seq_out;

	list_add_tail_rcu(&node->mac_list, node_db);

	return node;
}

/* Get the hsr_node from which 'skb' was sent.
 */
struct hsr_node *hsr_get_node(struct list_head *node_db, struct sk_buff *skb,
			      bool is_sup)
{
	struct hsr_node *node;
	struct ethhdr *ethhdr;
	u16 seq_out;

	if (!skb_mac_header_was_set(skb))
		return NULL;

	ethhdr = (struct ethhdr *) skb_mac_header(skb);

	list_for_each_entry_rcu(node, node_db, mac_list) {
		if (ether_addr_equal(node->MacAddressA, ethhdr->h_source))
			return node;
		if (ether_addr_equal(node->MacAddressB, ethhdr->h_source))
			return node;
	}

	/* Everyone may create a node entry, connected node to a HSR device. */

	if (ethhdr->h_proto == htons(ETH_P_PRP)
			|| ethhdr->h_proto == htons(ETH_P_HSR)) {
		/* Use the existing sequence_nr from the tag as starting point
		 * for filtering duplicate frames.
		 */
		seq_out = hsr_get_skb_sequence_nr(skb) - 1;
	} else {
		WARN_ONCE(1, "%s: Non-HSR frame\n", __func__);
		seq_out = HSR_SEQNR_START;
	}

	return hsr_add_node(node_db, ethhdr->h_source, seq_out);
}

/* Use the Supervision frame's info about an eventual MacAddressB for merging
 * nodes that has previously had their MacAddressB registered as a separate
 * node.
 */
void hsr_handle_sup_frame(struct sk_buff *skb, struct hsr_node *node_curr,
			  struct hsr_port *port_rcv)
{
	struct ethhdr *ethhdr;
	struct hsr_node *node_real;
	struct hsr_sup_payload *hsr_sp;
	struct list_head *node_db;
	int i;

	ethhdr = (struct ethhdr *) skb_mac_header(skb);

	/* Leave the ethernet header. */
	skb_pull(skb, sizeof(struct ethhdr));

	/* And leave the HSR tag. */
	if (ethhdr->h_proto == htons(ETH_P_HSR))
		skb_pull(skb, sizeof(struct hsr_tag));

	/* And leave the HSR sup tag. */
	skb_pull(skb, sizeof(struct hsr_sup_tag));

	hsr_sp = (struct hsr_sup_payload *) skb->data;

	/* Merge node_curr (registered on MacAddressB) into node_real */
	node_db = &port_rcv->hsr->node_db;
	node_real = find_node_by_AddrA(node_db, hsr_sp->MacAddressA);
	if (!node_real)
		/* No frame received from AddrA of this node yet */
		node_real = hsr_add_node(node_db, hsr_sp->MacAddressA,
					 HSR_SEQNR_START - 1);
	if (!node_real)
		goto done; /* No mem */
	if (node_real == node_curr)
		/* Node has already been merged */
		goto done;

	ether_addr_copy(node_real->MacAddressB, ethhdr->h_source);
	for (i = 0; i < HSR_PT_PORTS; i++) {
		if (!node_curr->time_in_stale[i] &&
		    time_after(node_curr->time_in[i], node_real->time_in[i])) {
			node_real->time_in[i] = node_curr->time_in[i];
			node_real->time_in_stale[i] = node_curr->time_in_stale[i];
		}
		if (seq_nr_after(node_curr->seq_out[i], node_real->seq_out[i]))
			node_real->seq_out[i] = node_curr->seq_out[i];
	}
	node_real->AddrB_port = port_rcv->type;

	list_del_rcu(&node_curr->mac_list);
	kfree_rcu(node_curr, rcu_head);

done:
	skb_push(skb, sizeof(struct hsrv1_ethhdr_sp));
}


/* 'skb' is a frame meant for this host, that is to be passed to upper layers.
 *
 * If the frame was sent by a node's B interface, replace the source
 * address with that node's "official" address (MacAddressA) so that upper
 * layers recognize where it came from.
 */
void hsr_addr_subst_source(struct hsr_node *node, struct sk_buff *skb)
{
	if (!skb_mac_header_was_set(skb)) {
		WARN_ONCE(1, "%s: Mac header not set\n", __func__);
		return;
	}

	memcpy(&eth_hdr(skb)->h_source, node->MacAddressA, ETH_ALEN);
}

/* 'skb' is a frame meant for another host.
 * 'port' is the outgoing interface
 *
 * Substitute the target (dest) MAC address if necessary, so the it matches the
 * recipient interface MAC address, regardless of whether that is the
 * recipient's A or B interface.
 * This is needed to keep the packets flowing through switches that learn on
 * which "side" the different interfaces are.
 */
void hsr_addr_subst_dest(struct hsr_node *node_src, struct sk_buff *skb,
			 struct hsr_port *port)
{
	struct hsr_node *node_dst;

	if (!skb_mac_header_was_set(skb)) {
		WARN_ONCE(1, "%s: Mac header not set\n", __func__);
		return;
	}

	if (!is_unicast_ether_addr(eth_hdr(skb)->h_dest))
		return;

	node_dst = find_node_by_AddrA(&port->hsr->node_db, eth_hdr(skb)->h_dest);
	if (!node_dst) {
		WARN_ONCE(1, "%s: Unknown node\n", __func__);
		return;
	}
	if (port->type != node_dst->AddrB_port)
		return;

	ether_addr_copy(eth_hdr(skb)->h_dest, node_dst->MacAddressB);
}


void hsr_register_frame_in(struct hsr_node *node, struct hsr_port *port,
			   u16 sequence_nr)
{
	/* Don't register incoming frames without a valid sequence number. This
	 * ensures entries of restarted nodes gets pruned so that they can
	 * re-register and resume communications.
	 */
	if (seq_nr_before(sequence_nr, node->seq_out[port->type]))
		return;

	node->time_in[port->type] = jiffies;
	node->time_in_stale[port->type] = false;
}

/* 'skb' is a HSR Ethernet frame (with a HSR tag inserted), with a valid
 * ethhdr->h_source address and skb->mac_header set.
 *
 * Return:
 *	 1 if frame can be shown to have been sent recently on this interface,
 *	 0 otherwise, or
 *	 negative error code on error
 */
int hsr_register_frame_out(struct hsr_port *port, struct hsr_node *node,
			   u16 sequence_nr)
{
	if (seq_nr_before_or_eq(sequence_nr, node->seq_out[port->type]))
		return 1;

	node->seq_out[port->type] = sequence_nr;
	return 0;
}


static struct hsr_port *get_late_port(struct hsr_priv *hsr,
				      struct hsr_node *node)
{
	if (node->time_in_stale[HSR_PT_SLAVE_A])
		return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
	if (node->time_in_stale[HSR_PT_SLAVE_B])
		return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);

	if (time_after(node->time_in[HSR_PT_SLAVE_B],
		       node->time_in[HSR_PT_SLAVE_A] +
					msecs_to_jiffies(MAX_SLAVE_DIFF)))
		return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
	if (time_after(node->time_in[HSR_PT_SLAVE_A],
		       node->time_in[HSR_PT_SLAVE_B] +
					msecs_to_jiffies(MAX_SLAVE_DIFF)))
		return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);

	return NULL;
}


/* Remove stale sequence_nr records. Called by timer every
 * HSR_LIFE_CHECK_INTERVAL (two seconds or so).
 */
void hsr_prune_nodes(unsigned long data)
{
	struct hsr_priv *hsr;
	struct hsr_node *node;
	struct hsr_port *port;
	unsigned long timestamp;
	unsigned long time_a, time_b;

	hsr = (struct hsr_priv *) data;

	rcu_read_lock();
	list_for_each_entry_rcu(node, &hsr->node_db, mac_list) {
		/* Shorthand */
		time_a = node->time_in[HSR_PT_SLAVE_A];
		time_b = node->time_in[HSR_PT_SLAVE_B];

		/* Check for timestamps old enough to risk wrap-around */
		if (time_after(jiffies, time_a + MAX_JIFFY_OFFSET/2))
			node->time_in_stale[HSR_PT_SLAVE_A] = true;
		if (time_after(jiffies, time_b + MAX_JIFFY_OFFSET/2))
			node->time_in_stale[HSR_PT_SLAVE_B] = true;

		/* Get age of newest frame from node.
		 * At least one time_in is OK here; nodes get pruned long
		 * before both time_ins can get stale
		 */
		timestamp = time_a;
		if (node->time_in_stale[HSR_PT_SLAVE_A] ||
		    (!node->time_in_stale[HSR_PT_SLAVE_B] &&
		    time_after(time_b, time_a)))
			timestamp = time_b;

		/* Warn of ring error only as long as we get frames at all */
		if (time_is_after_jiffies(timestamp +
					msecs_to_jiffies(1.5*MAX_SLAVE_DIFF))) {
			rcu_read_lock();
			port = get_late_port(hsr, node);
			if (port != NULL)
				hsr_nl_ringerror(hsr, node->MacAddressA, port);
			rcu_read_unlock();
		}

		/* Prune old entries */
		if (time_is_before_jiffies(timestamp +
					msecs_to_jiffies(HSR_NODE_FORGET_TIME))) {
			hsr_nl_nodedown(hsr, node->MacAddressA);
			list_del_rcu(&node->mac_list);
			/* Note that we need to free this entry later: */
			kfree_rcu(node, rcu_head);
		}
	}
	rcu_read_unlock();
}


void *hsr_get_next_node(struct hsr_priv *hsr, void *_pos,
			unsigned char addr[ETH_ALEN])
{
	struct hsr_node *node;

	if (!_pos) {
		node = list_first_or_null_rcu(&hsr->node_db,
					      struct hsr_node, mac_list);
		if (node)
			ether_addr_copy(addr, node->MacAddressA);
		return node;
	}

	node = _pos;
	list_for_each_entry_continue_rcu(node, &hsr->node_db, mac_list) {
		ether_addr_copy(addr, node->MacAddressA);
		return node;
	}

	return NULL;
}


int hsr_get_node_data(struct hsr_priv *hsr,
		      const unsigned char *addr,
		      unsigned char addr_b[ETH_ALEN],
		      unsigned int *addr_b_ifindex,
		      int *if1_age,
		      u16 *if1_seq,
		      int *if2_age,
		      u16 *if2_seq)
{
	struct hsr_node *node;
	struct hsr_port *port;
	unsigned long tdiff;


	rcu_read_lock();
	node = find_node_by_AddrA(&hsr->node_db, addr);
	if (!node) {
		rcu_read_unlock();
		return -ENOENT;	/* No such entry */
	}

	ether_addr_copy(addr_b, node->MacAddressB);

	tdiff = jiffies - node->time_in[HSR_PT_SLAVE_A];
	if (node->time_in_stale[HSR_PT_SLAVE_A])
		*if1_age = INT_MAX;
#if HZ <= MSEC_PER_SEC
	else if (tdiff > msecs_to_jiffies(INT_MAX))
		*if1_age = INT_MAX;
#endif
	else
		*if1_age = jiffies_to_msecs(tdiff);

	tdiff = jiffies - node->time_in[HSR_PT_SLAVE_B];
	if (node->time_in_stale[HSR_PT_SLAVE_B])
		*if2_age = INT_MAX;
#if HZ <= MSEC_PER_SEC
	else if (tdiff > msecs_to_jiffies(INT_MAX))
		*if2_age = INT_MAX;
#endif
	else
		*if2_age = jiffies_to_msecs(tdiff);

	/* Present sequence numbers as if they were incoming on interface */
	*if1_seq = node->seq_out[HSR_PT_SLAVE_B];
	*if2_seq = node->seq_out[HSR_PT_SLAVE_A];

	if (node->AddrB_port != HSR_PT_NONE) {
		port = hsr_port_get_hsr(hsr, node->AddrB_port);
		*addr_b_ifindex = port->dev->ifindex;
	} else {
		*addr_b_ifindex = -1;
	}

	rcu_read_unlock();

	return 0;
}
Commit	Line	Data
70ebe4a4	1	/* Copyright 2011-2014 Autronica Fire and Security AS
f421436a AB	2	*
	3	* This program is free software; you can redistribute it and/or modify it
	4	* under the terms of the GNU General Public License as published by the Free
	5	* Software Foundation; either version 2 of the License, or (at your option)
	6	* any later version.
	7	*
	8	* Author(s):
70ebe4a4	9	* 2011-2014 Arvid Brodin, arvid.brodin@alten.se
f421436a AB	10	*
	11	* The HSR spec says never to forward the same frame twice on the same
	12	* interface. A frame is identified by its source MAC address and its HSR
	13	* sequence number. This code keeps track of senders and their sequence numbers
	14	* to allow filtering of duplicate frames, and to detect HSR ring errors.
	15	*/
	16
	17	#include <linux/if_ether.h>
	18	#include <linux/etherdevice.h>
	19	#include <linux/slab.h>
	20	#include <linux/rculist.h>
	21	#include "hsr_main.h"
	22	#include "hsr_framereg.h"
	23	#include "hsr_netlink.h"
	24
	25
70ebe4a4 AB	26	struct hsr_node {
	27	struct list_head mac_list;
	28	unsigned char MacAddressA[ETH_ALEN];
	29	unsigned char MacAddressB[ETH_ALEN];
c5a75911 AB	30	/* Local slave through which AddrB frames are received from this node */
	31	enum hsr_port_type AddrB_port;
	32	unsigned long time_in[HSR_PT_PORTS];
	33	bool time_in_stale[HSR_PT_PORTS];
	34	u16 seq_out[HSR_PT_PORTS];
70ebe4a4	35	struct rcu_head rcu_head;
f421436a AB	36	};
f421436a AB	37
f421436a	38
f266a683	39	/* TODO: use hash lists for mac addresses (linux/jhash.h)? */
f421436a AB	40
f421436a AB	41
f266a683 AB	42	/* seq_nr_after(a, b) - return true if a is after (higher in sequence than) b,
f266a683 AB	43	* false otherwise.
f421436a	44	*/
f266a683	45	static bool seq_nr_after(u16 a, u16 b)
f421436a	46	{
f266a683 AB	47	/* Remove inconsistency where
	48	* seq_nr_after(a, b) == seq_nr_before(a, b)
	49	*/
	50	if ((int) b - a == 32768)
	51	return false;
f421436a	52
f266a683	53	return (((s16) (b - a)) < 0);
f421436a	54	}
f266a683 AB	55	#define seq_nr_before(a, b) seq_nr_after((b), (a))
	56	#define seq_nr_after_or_eq(a, b) (!seq_nr_before((a), (b)))
	57	#define seq_nr_before_or_eq(a, b) (!seq_nr_after((a), (b)))
f421436a AB	58
f421436a AB	59
f266a683	60	bool hsr_addr_is_self(struct hsr_priv hsr, unsigned char addr)
f421436a	61	{
70ebe4a4	62	struct hsr_node *node;
f421436a	63
f266a683 AB	64	node = list_first_or_null_rcu(&hsr->self_node_db, struct hsr_node,
	65	mac_list);
	66	if (!node) {
	67	WARN_ONCE(1, "HSR: No self node\n");
	68	return false;
f421436a AB	69	}
f421436a AB	70
f266a683 AB	71	if (ether_addr_equal(addr, node->MacAddressA))
	72	return true;
	73	if (ether_addr_equal(addr, node->MacAddressB))
	74	return true;
f421436a	75
f266a683 AB	76	return false;
f266a683 AB	77	}
f421436a AB	78
	79	/* Search for mac entry. Caller must hold rcu read lock.
	80	*/
f266a683 AB	81	static struct hsr_node find_node_by_AddrA(struct list_head node_db,
f266a683 AB	82	const unsigned char addr[ETH_ALEN])
f421436a	83	{
70ebe4a4	84	struct hsr_node *node;
f421436a AB	85
f421436a AB	86	list_for_each_entry_rcu(node, node_db, mac_list) {
f266a683	87	if (ether_addr_equal(node->MacAddressA, addr))
f421436a AB	88	return node;
	89	}
	90
	91	return NULL;
	92	}
	93
	94
	95	/* Helper for device init; the self_node_db is used in hsr_rcv() to recognize
	96	* frames from self that's been looped over the HSR ring.
	97	*/
	98	int hsr_create_self_node(struct list_head *self_node_db,
	99	unsigned char addr_a[ETH_ALEN],
	100	unsigned char addr_b[ETH_ALEN])
	101	{
70ebe4a4	102	struct hsr_node node, oldnode;
f421436a AB	103
	104	node = kmalloc(sizeof(*node), GFP_KERNEL);
	105	if (!node)
	106	return -ENOMEM;
	107
e83abe37 JP	108	ether_addr_copy(node->MacAddressA, addr_a);
e83abe37 JP	109	ether_addr_copy(node->MacAddressB, addr_b);
f421436a AB	110
	111	rcu_read_lock();
	112	oldnode = list_first_or_null_rcu(self_node_db,
70ebe4a4	113	struct hsr_node, mac_list);
f421436a AB	114	if (oldnode) {
	115	list_replace_rcu(&oldnode->mac_list, &node->mac_list);
	116	rcu_read_unlock();
	117	synchronize_rcu();
	118	kfree(oldnode);
	119	} else {
	120	rcu_read_unlock();
	121	list_add_tail_rcu(&node->mac_list, self_node_db);
	122	}
	123
	124	return 0;
	125	}
	126
f421436a	127
f266a683 AB	128	/* Allocate an hsr_node and add it to node_db. 'addr' is the node's AddressA;
	129	* seq_out is used to initialize filtering of outgoing duplicate frames
	130	* originating from the newly added node.
f421436a	131	*/
f266a683 AB	132	struct hsr_node hsr_add_node(struct list_head node_db, unsigned char addr[],
f266a683 AB	133	u16 seq_out)
f421436a	134	{
f266a683	135	struct hsr_node *node;
f421436a	136	unsigned long now;
f266a683	137	int i;
f421436a AB	138
	139	node = kzalloc(sizeof(*node), GFP_ATOMIC);
	140	if (!node)
	141	return NULL;
	142
f266a683	143	ether_addr_copy(node->MacAddressA, addr);
f421436a AB	144
	145	/* We are only interested in time diffs here, so use current jiffies
	146	* as initialization. (0 could trigger an spurious ring error warning).
	147	*/
	148	now = jiffies;
c5a75911	149	for (i = 0; i < HSR_PT_PORTS; i++)
f421436a	150	node->time_in[i] = now;
c5a75911	151	for (i = 0; i < HSR_PT_PORTS; i++)
f266a683	152	node->seq_out[i] = seq_out;
f421436a	153
f266a683	154	list_add_tail_rcu(&node->mac_list, node_db);
f421436a AB	155
	156	return node;
	157	}
	158
f266a683 AB	159	/* Get the hsr_node from which 'skb' was sent.
	160	*/
	161	struct hsr_node hsr_get_node(struct list_head node_db, struct sk_buff *skb,
	162	bool is_sup)
	163	{
	164	struct hsr_node *node;
	165	struct ethhdr *ethhdr;
	166	u16 seq_out;
	167
	168	if (!skb_mac_header_was_set(skb))
	169	return NULL;
	170
	171	ethhdr = (struct ethhdr *) skb_mac_header(skb);
	172
	173	list_for_each_entry_rcu(node, node_db, mac_list) {
	174	if (ether_addr_equal(node->MacAddressA, ethhdr->h_source))
	175	return node;
	176	if (ether_addr_equal(node->MacAddressB, ethhdr->h_source))
	177	return node;
	178	}
	179
ee1c2797	180	/* Everyone may create a node entry, connected node to a HSR device. */
f266a683	181
ee1c2797 PH	182	if (ethhdr->h_proto == htons(ETH_P_PRP)
ee1c2797 PH	183	\|\| ethhdr->h_proto == htons(ETH_P_HSR)) {
f266a683 AB	184	/* Use the existing sequence_nr from the tag as starting point
	185	* for filtering duplicate frames.
	186	*/
	187	seq_out = hsr_get_skb_sequence_nr(skb) - 1;
	188	} else {
	189	WARN_ONCE(1, "%s: Non-HSR frame\n", __func__);
ee1c2797	190	seq_out = HSR_SEQNR_START;
f266a683 AB	191	}
	192
	193	return hsr_add_node(node_db, ethhdr->h_source, seq_out);
	194	}
	195
	196	/* Use the Supervision frame's info about an eventual MacAddressB for merging
	197	* nodes that has previously had their MacAddressB registered as a separate
	198	* node.
	199	*/
	200	void hsr_handle_sup_frame(struct sk_buff skb, struct hsr_node node_curr,
	201	struct hsr_port *port_rcv)
	202	{
ee1c2797	203	struct ethhdr *ethhdr;
f266a683 AB	204	struct hsr_node *node_real;
	205	struct hsr_sup_payload *hsr_sp;
	206	struct list_head *node_db;
	207	int i;
	208
ee1c2797	209	ethhdr = (struct ethhdr *) skb_mac_header(skb);
f266a683	210
ee1c2797 PH	211	/* Leave the ethernet header. */
	212	skb_pull(skb, sizeof(struct ethhdr));
	213
	214	/* And leave the HSR tag. */
	215	if (ethhdr->h_proto == htons(ETH_P_HSR))
	216	skb_pull(skb, sizeof(struct hsr_tag));
	217
	218	/* And leave the HSR sup tag. */
	219	skb_pull(skb, sizeof(struct hsr_sup_tag));
	220
	221	hsr_sp = (struct hsr_sup_payload *) skb->data;
f266a683 AB	222
	223	/* Merge node_curr (registered on MacAddressB) into node_real */
	224	node_db = &port_rcv->hsr->node_db;
	225	node_real = find_node_by_AddrA(node_db, hsr_sp->MacAddressA);
	226	if (!node_real)
	227	/* No frame received from AddrA of this node yet */
	228	node_real = hsr_add_node(node_db, hsr_sp->MacAddressA,
	229	HSR_SEQNR_START - 1);
	230	if (!node_real)
	231	goto done; /* No mem */
	232	if (node_real == node_curr)
	233	/* Node has already been merged */
	234	goto done;
	235
ee1c2797	236	ether_addr_copy(node_real->MacAddressB, ethhdr->h_source);
f266a683 AB	237	for (i = 0; i < HSR_PT_PORTS; i++) {
	238	if (!node_curr->time_in_stale[i] &&
	239	time_after(node_curr->time_in[i], node_real->time_in[i])) {
	240	node_real->time_in[i] = node_curr->time_in[i];
	241	node_real->time_in_stale[i] = node_curr->time_in_stale[i];
	242	}
	243	if (seq_nr_after(node_curr->seq_out[i], node_real->seq_out[i]))
	244	node_real->seq_out[i] = node_curr->seq_out[i];
	245	}
	246	node_real->AddrB_port = port_rcv->type;
	247
	248	list_del_rcu(&node_curr->mac_list);
	249	kfree_rcu(node_curr, rcu_head);
	250
	251	done:
ee1c2797	252	skb_push(skb, sizeof(struct hsrv1_ethhdr_sp));
f266a683 AB	253	}
f266a683 AB	254
f421436a AB	255
	256	/* 'skb' is a frame meant for this host, that is to be passed to upper layers.
	257	*
f266a683	258	* If the frame was sent by a node's B interface, replace the source
f421436a AB	259	* address with that node's "official" address (MacAddressA) so that upper
	260	* layers recognize where it came from.
	261	*/
f266a683	262	void hsr_addr_subst_source(struct hsr_node node, struct sk_buff skb)
f421436a	263	{
f421436a AB	264	if (!skb_mac_header_was_set(skb)) {
	265	WARN_ONCE(1, "%s: Mac header not set\n", __func__);
	266	return;
	267	}
f421436a	268
f266a683	269	memcpy(&eth_hdr(skb)->h_source, node->MacAddressA, ETH_ALEN);
f421436a AB	270	}
f421436a AB	271
f421436a	272	/* 'skb' is a frame meant for another host.
f266a683	273	* 'port' is the outgoing interface
f421436a AB	274	*
	275	* Substitute the target (dest) MAC address if necessary, so the it matches the
	276	* recipient interface MAC address, regardless of whether that is the
	277	* recipient's A or B interface.
	278	* This is needed to keep the packets flowing through switches that learn on
	279	* which "side" the different interfaces are.
	280	*/
f266a683	281	void hsr_addr_subst_dest(struct hsr_node node_src, struct sk_buff skb,
c5a75911	282	struct hsr_port *port)
f421436a	283	{
f266a683	284	struct hsr_node *node_dst;
f421436a	285
f266a683 AB	286	if (!skb_mac_header_was_set(skb)) {
	287	WARN_ONCE(1, "%s: Mac header not set\n", __func__);
	288	return;
	289	}
f421436a	290
f266a683 AB	291	if (!is_unicast_ether_addr(eth_hdr(skb)->h_dest))
f266a683 AB	292	return;
f421436a	293
f266a683 AB	294	node_dst = find_node_by_AddrA(&port->hsr->node_db, eth_hdr(skb)->h_dest);
	295	if (!node_dst) {
	296	WARN_ONCE(1, "%s: Unknown node\n", __func__);
	297	return;
	298	}
	299	if (port->type != node_dst->AddrB_port)
	300	return;
f421436a	301
f266a683	302	ether_addr_copy(eth_hdr(skb)->h_dest, node_dst->MacAddressB);
f421436a	303	}
f421436a AB	304
f421436a AB	305
f266a683 AB	306	void hsr_register_frame_in(struct hsr_node node, struct hsr_port port,
f266a683 AB	307	u16 sequence_nr)
f421436a	308	{
f266a683 AB	309	/* Don't register incoming frames without a valid sequence number. This
	310	* ensures entries of restarted nodes gets pruned so that they can
	311	* re-register and resume communications.
	312	*/
	313	if (seq_nr_before(sequence_nr, node->seq_out[port->type]))
	314	return;
	315
c5a75911 AB	316	node->time_in[port->type] = jiffies;
c5a75911 AB	317	node->time_in_stale[port->type] = false;
f421436a AB	318	}
f421436a AB	319
f421436a AB	320	/* 'skb' is a HSR Ethernet frame (with a HSR tag inserted), with a valid
	321	* ethhdr->h_source address and skb->mac_header set.
	322	*
	323	* Return:
	324	* 1 if frame can be shown to have been sent recently on this interface,
	325	* 0 otherwise, or
	326	* negative error code on error
	327	*/
f266a683 AB	328	int hsr_register_frame_out(struct hsr_port port, struct hsr_node node,
f266a683 AB	329	u16 sequence_nr)
f421436a	330	{
c5a75911	331	if (seq_nr_before_or_eq(sequence_nr, node->seq_out[port->type]))
f421436a AB	332	return 1;
f421436a AB	333
c5a75911	334	node->seq_out[port->type] = sequence_nr;
f421436a AB	335	return 0;
	336	}
	337
	338
c5a75911 AB	339	static struct hsr_port get_late_port(struct hsr_priv hsr,
c5a75911 AB	340	struct hsr_node *node)
f421436a	341	{
c5a75911 AB	342	if (node->time_in_stale[HSR_PT_SLAVE_A])
	343	return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
	344	if (node->time_in_stale[HSR_PT_SLAVE_B])
	345	return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
	346
	347	if (time_after(node->time_in[HSR_PT_SLAVE_B],
	348	node->time_in[HSR_PT_SLAVE_A] +
	349	msecs_to_jiffies(MAX_SLAVE_DIFF)))
	350	return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
	351	if (time_after(node->time_in[HSR_PT_SLAVE_A],
	352	node->time_in[HSR_PT_SLAVE_B] +
	353	msecs_to_jiffies(MAX_SLAVE_DIFF)))
	354	return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
f421436a	355
c5a75911	356	return NULL;
f421436a AB	357	}
	358
	359
	360	/* Remove stale sequence_nr records. Called by timer every
	361	* HSR_LIFE_CHECK_INTERVAL (two seconds or so).
	362	*/
abff7162	363	void hsr_prune_nodes(unsigned long data)
f421436a	364	{
abff7162	365	struct hsr_priv *hsr;
70ebe4a4	366	struct hsr_node *node;
c5a75911	367	struct hsr_port *port;
f421436a AB	368	unsigned long timestamp;
	369	unsigned long time_a, time_b;
	370
abff7162 AB	371	hsr = (struct hsr_priv *) data;
abff7162 AB	372
f421436a	373	rcu_read_lock();
70ebe4a4	374	list_for_each_entry_rcu(node, &hsr->node_db, mac_list) {
f421436a	375	/* Shorthand */
c5a75911 AB	376	time_a = node->time_in[HSR_PT_SLAVE_A];
c5a75911 AB	377	time_b = node->time_in[HSR_PT_SLAVE_B];
f421436a AB	378
	379	/* Check for timestamps old enough to risk wrap-around */
	380	if (time_after(jiffies, time_a + MAX_JIFFY_OFFSET/2))
c5a75911	381	node->time_in_stale[HSR_PT_SLAVE_A] = true;
f421436a	382	if (time_after(jiffies, time_b + MAX_JIFFY_OFFSET/2))
c5a75911	383	node->time_in_stale[HSR_PT_SLAVE_B] = true;
f421436a AB	384
	385	/* Get age of newest frame from node.
	386	* At least one time_in is OK here; nodes get pruned long
	387	* before both time_ins can get stale
	388	*/
	389	timestamp = time_a;
c5a75911 AB	390	if (node->time_in_stale[HSR_PT_SLAVE_A] \|\|
c5a75911 AB	391	(!node->time_in_stale[HSR_PT_SLAVE_B] &&
f421436a AB	392	time_after(time_b, time_a)))
	393	timestamp = time_b;
	394
	395	/* Warn of ring error only as long as we get frames at all */
	396	if (time_is_after_jiffies(timestamp +
	397	msecs_to_jiffies(1.5*MAX_SLAVE_DIFF))) {
c5a75911 AB	398	rcu_read_lock();
	399	port = get_late_port(hsr, node);
	400	if (port != NULL)
	401	hsr_nl_ringerror(hsr, node->MacAddressA, port);
	402	rcu_read_unlock();
f421436a AB	403	}
	404
	405	/* Prune old entries */
	406	if (time_is_before_jiffies(timestamp +
	407	msecs_to_jiffies(HSR_NODE_FORGET_TIME))) {
70ebe4a4	408	hsr_nl_nodedown(hsr, node->MacAddressA);
f421436a AB	409	list_del_rcu(&node->mac_list);
f421436a AB	410	/* Note that we need to free this entry later: */
1aee6cc2	411	kfree_rcu(node, rcu_head);
f421436a AB	412	}
	413	}
	414	rcu_read_unlock();
	415	}
	416
	417
70ebe4a4	418	void hsr_get_next_node(struct hsr_priv hsr, void *_pos,
f421436a AB	419	unsigned char addr[ETH_ALEN])
f421436a AB	420	{
70ebe4a4	421	struct hsr_node *node;
f421436a AB	422
f421436a AB	423	if (!_pos) {
70ebe4a4 AB	424	node = list_first_or_null_rcu(&hsr->node_db,
70ebe4a4 AB	425	struct hsr_node, mac_list);
f421436a	426	if (node)
e83abe37	427	ether_addr_copy(addr, node->MacAddressA);
f421436a AB	428	return node;
	429	}
	430
	431	node = _pos;
70ebe4a4	432	list_for_each_entry_continue_rcu(node, &hsr->node_db, mac_list) {
e83abe37	433	ether_addr_copy(addr, node->MacAddressA);
f421436a AB	434	return node;
	435	}
	436
	437	return NULL;
	438	}
	439
	440
70ebe4a4	441	int hsr_get_node_data(struct hsr_priv *hsr,
f421436a AB	442	const unsigned char *addr,
	443	unsigned char addr_b[ETH_ALEN],
	444	unsigned int *addr_b_ifindex,
	445	int *if1_age,
	446	u16 *if1_seq,
	447	int *if2_age,
	448	u16 *if2_seq)
	449	{
70ebe4a4	450	struct hsr_node *node;
c5a75911	451	struct hsr_port *port;
f421436a AB	452	unsigned long tdiff;
	453
	454
	455	rcu_read_lock();
70ebe4a4	456	node = find_node_by_AddrA(&hsr->node_db, addr);
f421436a AB	457	if (!node) {
	458	rcu_read_unlock();
	459	return -ENOENT; /* No such entry */
	460	}
	461
e83abe37	462	ether_addr_copy(addr_b, node->MacAddressB);
f421436a	463
c5a75911 AB	464	tdiff = jiffies - node->time_in[HSR_PT_SLAVE_A];
c5a75911 AB	465	if (node->time_in_stale[HSR_PT_SLAVE_A])
f421436a AB	466	*if1_age = INT_MAX;
	467	#if HZ <= MSEC_PER_SEC
	468	else if (tdiff > msecs_to_jiffies(INT_MAX))
	469	*if1_age = INT_MAX;
	470	#endif
	471	else
	472	*if1_age = jiffies_to_msecs(tdiff);
	473
c5a75911 AB	474	tdiff = jiffies - node->time_in[HSR_PT_SLAVE_B];
c5a75911 AB	475	if (node->time_in_stale[HSR_PT_SLAVE_B])
f421436a AB	476	*if2_age = INT_MAX;
	477	#if HZ <= MSEC_PER_SEC
	478	else if (tdiff > msecs_to_jiffies(INT_MAX))
	479	*if2_age = INT_MAX;
	480	#endif
	481	else
	482	*if2_age = jiffies_to_msecs(tdiff);
	483
	484	/* Present sequence numbers as if they were incoming on interface */
c5a75911 AB	485	*if1_seq = node->seq_out[HSR_PT_SLAVE_B];
c5a75911 AB	486	*if2_seq = node->seq_out[HSR_PT_SLAVE_A];
f421436a	487
c5a75911 AB	488	if (node->AddrB_port != HSR_PT_NONE) {
	489	port = hsr_port_get_hsr(hsr, node->AddrB_port);
	490	*addr_b_ifindex = port->dev->ifindex;
	491	} else {
f421436a	492	*addr_b_ifindex = -1;
c5a75911	493	}
f421436a AB	494
	495	rcu_read_unlock();
	496
	497	return 0;
	498	}