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;
+}