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-rw-r--r--net/hsr/hsr_framereg.c503
1 files changed, 503 insertions, 0 deletions
diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c
new file mode 100644
index 000000000000..003f5bb3acd2
--- /dev/null
+++ b/net/hsr/hsr_framereg.c
@@ -0,0 +1,503 @@
+/* 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;
+}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.