/* Copyright 2011-2013 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):
* 2011-2013 Arvid Brodin, arvid.brodin@xdin.com
*
* 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 node_entry {
struct list_head mac_list;
unsigned char MacAddressA[ETH_ALEN];
unsigned char MacAddressB[ETH_ALEN];
enum hsr_dev_idx AddrB_if; /* The local slave through which AddrB
* frames are received from this node
*/
unsigned long time_in[HSR_MAX_SLAVE];
bool time_in_stale[HSR_MAX_SLAVE];
u16 seq_out[HSR_MAX_DEV];
struct rcu_head rcu_head;
};
/* TODO: use hash lists for mac addresses (linux/jhash.h)? */
/* Search for mac entry. Caller must hold rcu read lock.
*/
static struct node_entry *find_node_by_AddrA(struct list_head *node_db,
const unsigned char addr[ETH_ALEN])
{
struct node_entry *node;
list_for_each_entry_rcu(node, node_db, mac_list) {
if (ether_addr_equal(node->MacAddressA, addr))
return node;
}
return NULL;
}
/* Search for mac entry. Caller must hold rcu read lock.
*/
static struct node_entry *find_node_by_AddrB(struct list_head *node_db,
const unsigned char addr[ETH_ALEN])
{
struct node_entry *node;
list_for_each_entry_rcu(node, node_db, mac_list) {
if (ether_addr_equal(node->MacAddressB, addr))
return node;
}
return NULL;
}
/* Search for mac entry. Caller must hold rcu read lock.
*/
struct node_entry *hsr_find_node(struct list_head *node_db, struct sk_buff *skb)
{
struct node_entry *node;
struct ethhdr *ethhdr;
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;
}
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 node_entry *node, *oldnode;
node = kmalloc(sizeof(*node), GFP_KERNEL);
if (!node)
return -ENOMEM;
memcpy(node->MacAddressA, addr_a, ETH_ALEN);
memcpy(node->MacAddressB, addr_b, ETH_ALEN);
rcu_read_lock();
oldnode = list_first_or_null_rcu(self_node_db,
struct node_entry, 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;
}
static void node_entry_reclaim(struct rcu_head *rh)
{
kfree(container_of(rh, struct node_entry, rcu_head));
}
/* Add/merge node to the database of nodes. 'skb' must contain an HSR
* supervision frame.
* - If the supervision header's MacAddressA field is not yet in the database,
* this frame is from an hitherto unknown node - add it to the database.
* - If the sender's MAC address is not the same as its MacAddressA address,
* the node is using PICS_SUBS (address substitution). Record the sender's
* address as the node's MacAddressB.
*
* This function needs to work even if the sender node has changed one of its
* slaves' MAC addresses. In this case, there are four different cases described
* by (Addr-changed, received-from) pairs as follows. Note that changing the
* SlaveA address is equal to changing the node's own address:
*
* - (AddrB, SlaveB): The new AddrB will be recorded by PICS_SUBS code since
* node == NULL.
* - (AddrB, SlaveA): Will work as usual (the AddrB change won't be detected
* from this frame).
*
* - (AddrA, SlaveB): The old node will be found. We need to detect this and
* remove the node.
* - (AddrA, SlaveA): A new node will be registered (non-PICS_SUBS at first).
* The old one will be pruned after HSR_NODE_FORGET_TIME.
*
* We also need to detect if the sender's SlaveA and SlaveB cables have been
* swapped.
*/
struct node_entry *hsr_merge_node(struct hsr_priv *hsr_priv,
struct node_entry *node,
struct sk_buff *skb,
enum hsr_dev_idx dev_idx)
{
struct hsr_sup_payload *hsr_sp;
struct hsr_ethhdr_sp *hsr_ethsup;
int i;
unsigned long now;
hsr_ethsup = (struct hsr_ethhdr_sp *) skb_mac_header(skb);
hsr_sp = (struct hsr_sup_payload *) skb->data;
if (node && !ether_addr_equal(node->MacAddressA, hsr_sp->MacAddressA)) {
/* Node has changed its AddrA, frame was received from SlaveB */
list_del_rcu(&node->mac_list);
call_rcu(&node->rcu_head, node_entry_reclaim);
node = NULL;
}
if (node && (dev_idx == node->AddrB_if) &&
!ether_addr_equal(node->MacAddressB, hsr_ethsup->ethhdr.h_source)) {
/* Cables have been swapped */
list_del_rcu(&node->mac_list);
call_rcu(&node->rcu_head, node_entry_reclaim);
node = NULL;
}
if (node && (dev_idx != node->AddrB_if) &&
(node->AddrB_if != HSR_DEV_NONE) &&
!ether_addr_equal(node->MacAddressA, hsr_ethsup->ethhdr.h_source)) {
/* Cables have been swapped */
list_del_rcu(&node->mac_list);
call_rcu(&node->rcu_head, node_entry_reclaim);
node = NULL;
}
if (node)
return node;
node = find_node_by_AddrA(&hsr_priv->node_db, hsr_sp->MacAddressA);
if (node) {
/* Node is known, but frame was received from an unknown
* address. Node is PICS_SUBS capable; merge its AddrB.
*/
memcpy(node->MacAddressB, hsr_ethsup->ethhdr.h_source, ETH_ALEN);
node->AddrB_if = dev_idx;
return node;
}
node = kzalloc(sizeof(*node), GFP_ATOMIC);
if (!node)
return NULL;
memcpy(node->MacAddressA, hsr_sp->MacAddressA, ETH_ALEN);
memcpy(node->MacAddressB, hsr_ethsup->ethhdr.h_source, ETH_ALEN);
if (!ether_addr_equal(hsr_sp->MacAddressA, hsr_ethsup->ethhdr.h_source))
node->AddrB_if = dev_idx;
else
node->AddrB_if = HSR_DEV_NONE;
/* 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_MAX_SLAVE; i++)
node->time_in[i] = now;
for (i = 0; i < HSR_MAX_DEV; i++)
node->seq_out[i] = ntohs(hsr_ethsup->hsr_sup.sequence_nr) - 1;
list_add_tail_rcu(&node->mac_list, &hsr_priv->node_db);
return node;
}
/* '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 sender
* address with that node's "official" address (MacAddressA) so that upper
* layers recognize where it came from.
*/
void hsr_addr_subst_source(struct hsr_priv *hsr_priv, struct sk_buff *skb)
{
struct ethhdr *ethhdr;
struct node_entry *node;
if (!skb_mac_header_was_set(skb)) {
WARN_ONCE(1, "%s: Mac header not set\n", __func__);
return;
}
ethhdr = (struct ethhdr *) skb_mac_header(skb);
rcu_read_lock();
node = find_node_by_AddrB(&hsr_priv->node_db, ethhdr->h_source);
if (node)
memcpy(ethhdr->h_source, node->MacAddressA, ETH_ALEN);
rcu_read_unlock();
}
/* 'skb' is a frame meant for another host.
* 'hsr_dev_idx' is the HSR index of the outgoing device
*
* 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_priv *hsr_priv, struct ethhdr *ethhdr,
enum hsr_dev_idx dev_idx)
{
struct node_entry *node;
rcu_read_lock();
node = find_node_by_AddrA(&hsr_priv->node_db, ethhdr->h_dest);
if (node && (node->AddrB_if == dev_idx))
memcpy(ethhdr->h_dest, node->MacAddressB, ETH_ALEN);
rcu_read_unlock();
}
/* 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)))
void hsr_register_frame_in(struct node_entry *node, enum hsr_dev_idx dev_idx)
{
if ((dev_idx < 0) || (dev_idx >= HSR_MAX_DEV)) {
WARN_ONCE(1, "%s: Invalid dev_idx (%d)\n", __func__, dev_idx);
return;
}
node->time_in[dev_idx] = jiffies;
node->time_in_stale[dev_idx] = 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 node_entry *node, enum hsr_dev_idx dev_idx,
struct sk_buff *skb)
{
struct hsr_ethhdr *hsr_ethhdr;
u16 sequence_nr;
if ((dev_idx < 0) || (dev_idx >= HSR_MAX_DEV)) {
WARN_ONCE(1, "%s: Invalid dev_idx (%d)\n", __func__, dev_idx);
return -EINVAL;
}
if (!skb_mac_header_was_set(skb)) {
WARN_ONCE(1, "%s: Mac header not set\n", __func__);
return -EINVAL;
}
hsr_ethhdr = (struct hsr_ethhdr *) skb_mac_header(skb);
sequence_nr = ntohs(hsr_ethhdr->hsr_tag.sequence_nr);
if (seq_nr_before_or_eq(sequence_nr, node->seq_out[dev_idx]))
return 1;
node->seq_out[dev_idx] = sequence_nr;
return 0;
}
static bool is_late(struct node_entry *node, enum hsr_dev_idx dev_idx)
{
enum hsr_dev_idx other;
if (node->time_in_stale[dev_idx])
return true;
if (dev_idx == HSR_DEV_SLAVE_A)
other = HSR_DEV_SLAVE_B;
else
other = HSR_DEV_SLAVE_A;
if (node->time_in_stale[other])
return false;
if (time_after(node->time_in[other], node->time_in[dev_idx] +
msecs_to_jiffies(MAX_SLAVE_DIFF)))
return true;
return false;
}
/* Remove stale sequence_nr records. Called by timer every
* HSR_LIFE_CHECK_INTERVAL (two seconds or so).
*/
void hsr_prune_nodes(struct hsr_priv *hsr_priv)
{
struct node_entry *node;
unsigned long timestamp;
unsigned long time_a, time_b;
rcu_read_lock();
list_for_each_entry_rcu(node, &hsr_priv->node_db, mac_list) {
/* Shorthand */
time_a = node->time_in[HSR_DEV_SLAVE_A];
time_b = node->time_in[HSR_DEV_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_DEV_SLAVE_A] = true;
if (time_after(jiffies, time_b + MAX_JIFFY_OFFSET/2))
node->time_in_stale[HSR_DEV_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_DEV_SLAVE_A] ||
(!node->time_in_stale[HSR_DEV_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))) {
if (is_late(node, HSR_DEV_SLAVE_A))
hsr_nl_ringerror(hsr_priv, node->MacAddressA,
HSR_DEV_SLAVE_A);
else if (is_late(node, HSR_DEV_SLAVE_B))
hsr_nl_ringerror(hsr_priv, node->MacAddressA,
HSR_DEV_SLAVE_B);
}
/* Prune old entries */
if (time_is_before_jiffies(timestamp +
msecs_to_jiffies(HSR_NODE_FORGET_TIME))) {
hsr_nl_nodedown(hsr_priv, node->MacAddressA);
list_del_rcu(&node->mac_list);
/* Note that we need to free this entry later: */
call_rcu(&node->rcu_head, node_entry_reclaim);
}
}
rcu_read_unlock();
}
void *hsr_get_next_node(struct hsr_priv *hsr_priv, void *_pos,
unsigned char addr[ETH_ALEN])
{
struct node_entry *node;
if (!_pos) {
node = list_first_or_null_rcu(&hsr_priv->node_db,
struct node_entry, mac_list);
if (node)
memcpy(addr, node->MacAddressA, ETH_ALEN);
return node;
}
node = _pos;
list_for_each_entry_continue_rcu(node, &hsr_priv->node_db, mac_list) {
memcpy(addr, node->MacAddressA, ETH_ALEN);
return node;
}
return NULL;
}
int hsr_get_node_data(struct hsr_priv *hsr_priv,
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 node_entry *node;
unsigned long tdiff;
rcu_read_lock();
node = find_node_by_AddrA(&hsr_priv->node_db, addr);
if (!node) {
rcu_read_unlock();
return -ENOENT; /* No such entry */
}
memcpy(addr_b, node->MacAddressB, ETH_ALEN);
tdiff = jiffies - node->time_in[HSR_DEV_SLAVE_A];
if (node->time_in_stale[HSR_DEV_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_DEV_SLAVE_B];
if (node->time_in_stale[HSR_DEV_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_DEV_SLAVE_B];
*if2_seq = node->seq_out[HSR_DEV_SLAVE_A];
if ((node->AddrB_if != HSR_DEV_NONE) && hsr_priv->slave[node->AddrB_if])
*addr_b_ifindex = hsr_priv->slave[node->AddrB_if]->ifindex;
else
*addr_b_ifindex = -1;
rcu_read_unlock();
return 0;
}
