1 files changed, 508 insertions, 0 deletions

diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c
new file mode 100644
index 000000000..37795502b
--- /dev/null
+++ b/net/hsr/hsr_framereg.c
@@ -0,0 +1,508 @@
+/* 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;
+}
+
+void hsr_del_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);
+	}
+}
+
+/* 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 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->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 {
+		/* 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 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) {
+		if (net_ratelimit())
+			netdev_err(skb->dev, "%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(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) {
+		/* 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;
+
+	node = find_node_by_AddrA(&hsr->node_db, addr);
+	if (!node)
+		return -ENOENT;
+
+	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;
+	}
+
+	return 0;
+}