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// SPDX-License-Identifier: GPL-2.0
/* Copyright 2011-2014 Autronica Fire and Security AS
*
* 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"
/* 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->macaddress_A))
return true;
if (ether_addr_equal(addr, node->macaddress_B))
return true;
return false;
}
/* Search for mac entry. Caller must hold rcu read lock.
*/
static struct hsr_node *find_node_by_addr_A(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->macaddress_A, 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->macaddress_A, addr_a);
ether_addr_copy(node->macaddress_B, 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;
}
void hsr_del_self_node(struct list_head *self_node_db)
{
struct hsr_node *node;
rcu_read_lock();
node = list_first_or_null_rcu(self_node_db, struct hsr_node, mac_list);
rcu_read_unlock();
if (node) {
list_del_rcu(&node->mac_list);
kfree(node);
}
}
void hsr_del_nodes(struct list_head *node_db)
{
struct hsr_node *node;
struct hsr_node *tmp;
list_for_each_entry_safe(node, tmp, node_db, mac_list)
kfree(node);
}
/* Allocate an hsr_node and add it to node_db. 'addr' is the node's address_A;
* 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->macaddress_A, 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 hsr_port *port, struct sk_buff *skb,
bool is_sup)
{
struct list_head *node_db = &port->hsr->node_db;
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->macaddress_A, ethhdr->h_source))
return node;
if (ether_addr_equal(node->macaddress_B, 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 {
/* this is called also for frames from master port and
* so warn only for non master ports
*/
if (port->type != HSR_PT_MASTER)
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 macaddress_B for merging
* nodes that has previously had their macaddress_B 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 macaddress_B) into node_real */
node_db = &port_rcv->hsr->node_db;
node_real = find_node_by_addr_A(node_db, hsr_sp->macaddress_A);
if (!node_real)
/* No frame received from AddrA of this node yet */
node_real = hsr_add_node(node_db, hsr_sp->macaddress_A,
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->macaddress_B, 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->addr_B_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 (macaddress_A) 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->macaddress_A, 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_addr_A(&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->addr_B_port)
return;
ether_addr_copy(eth_hdr(skb)->h_dest, node_dst->macaddress_B);
}
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(struct timer_list *t)
{
struct hsr_priv *hsr = from_timer(hsr, t, prune_timer);
struct hsr_node *node;
struct hsr_port *port;
unsigned long timestamp;
unsigned long time_a, time_b;
rcu_read_lock();
list_for_each_entry_rcu(node, &hsr->node_db, mac_list) {
/* Don't prune own node. Neither time_in[HSR_PT_SLAVE_A]
* nor time_in[HSR_PT_SLAVE_B], will ever be updated for
* the master port. Thus the master node will be repeatedly
* pruned leading to packet loss.
*/
if (hsr_addr_is_self(hsr, node->macaddress_A))
continue;
/* 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)
hsr_nl_ringerror(hsr, node->macaddress_A, 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->macaddress_A);
list_del_rcu(&node->mac_list);
/* Note that we need to free this entry later: */
kfree_rcu(node, rcu_head);
}
}
rcu_read_unlock();
/* Restart timer */
mod_timer(&hsr->prune_timer,
jiffies + msecs_to_jiffies(PRUNE_PERIOD));
}
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->macaddress_A);
return node;
}
node = _pos;
list_for_each_entry_continue_rcu(node, &hsr->node_db, mac_list) {
ether_addr_copy(addr, node->macaddress_A);
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_addr_A(&hsr->node_db, addr);
if (!node) {
rcu_read_unlock();
return -ENOENT; /* No such entry */
}
ether_addr_copy(addr_b, node->macaddress_B);
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->addr_B_port != HSR_PT_NONE) {
port = hsr_port_get_hsr(hsr, node->addr_B_port);
*addr_b_ifindex = port->dev->ifindex;
} else {
*addr_b_ifindex = -1;
}
rcu_read_unlock();
return 0;
}