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-rw-r--r--net/hsr/hsr_main.c469
1 files changed, 469 insertions, 0 deletions
diff --git a/net/hsr/hsr_main.c b/net/hsr/hsr_main.c
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+++ b/net/hsr/hsr_main.c
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+/* 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
+ *
+ * In addition to routines for registering and unregistering HSR support, this
+ * file also contains the receive routine that handles all incoming frames with
+ * Ethertype (protocol) ETH_P_PRP (HSRv0), and network device event handling.
+ */
+
+#include <linux/netdevice.h>
+#include <linux/rculist.h>
+#include <linux/timer.h>
+#include <linux/etherdevice.h>
+#include "hsr_main.h"
+#include "hsr_device.h"
+#include "hsr_netlink.h"
+#include "hsr_framereg.h"
+
+
+/* List of all registered virtual HSR devices */
+static LIST_HEAD(hsr_list);
+
+void register_hsr_master(struct hsr_priv *hsr_priv)
+{
+ list_add_tail_rcu(&hsr_priv->hsr_list, &hsr_list);
+}
+
+void unregister_hsr_master(struct hsr_priv *hsr_priv)
+{
+ struct hsr_priv *hsr_priv_it;
+
+ list_for_each_entry(hsr_priv_it, &hsr_list, hsr_list)
+ if (hsr_priv_it == hsr_priv) {
+ list_del_rcu(&hsr_priv_it->hsr_list);
+ return;
+ }
+}
+
+bool is_hsr_slave(struct net_device *dev)
+{
+ struct hsr_priv *hsr_priv_it;
+
+ list_for_each_entry_rcu(hsr_priv_it, &hsr_list, hsr_list) {
+ if (dev == hsr_priv_it->slave[0])
+ return true;
+ if (dev == hsr_priv_it->slave[1])
+ return true;
+ }
+
+ return false;
+}
+
+
+/* If dev is a HSR slave device, return the virtual master device. Return NULL
+ * otherwise.
+ */
+static struct hsr_priv *get_hsr_master(struct net_device *dev)
+{
+ struct hsr_priv *hsr_priv;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(hsr_priv, &hsr_list, hsr_list)
+ if ((dev == hsr_priv->slave[0]) ||
+ (dev == hsr_priv->slave[1])) {
+ rcu_read_unlock();
+ return hsr_priv;
+ }
+
+ rcu_read_unlock();
+ return NULL;
+}
+
+
+/* If dev is a HSR slave device, return the other slave device. Return NULL
+ * otherwise.
+ */
+static struct net_device *get_other_slave(struct hsr_priv *hsr_priv,
+ struct net_device *dev)
+{
+ if (dev == hsr_priv->slave[0])
+ return hsr_priv->slave[1];
+ if (dev == hsr_priv->slave[1])
+ return hsr_priv->slave[0];
+
+ return NULL;
+}
+
+
+static int hsr_netdev_notify(struct notifier_block *nb, unsigned long event,
+ void *ptr)
+{
+ struct net_device *slave, *other_slave;
+ struct hsr_priv *hsr_priv;
+ int old_operstate;
+ int mtu_max;
+ int res;
+ struct net_device *dev;
+
+ dev = netdev_notifier_info_to_dev(ptr);
+
+ hsr_priv = get_hsr_master(dev);
+ if (hsr_priv) {
+ /* dev is a slave device */
+ slave = dev;
+ other_slave = get_other_slave(hsr_priv, slave);
+ } else {
+ if (!is_hsr_master(dev))
+ return NOTIFY_DONE;
+ hsr_priv = netdev_priv(dev);
+ slave = hsr_priv->slave[0];
+ other_slave = hsr_priv->slave[1];
+ }
+
+ switch (event) {
+ case NETDEV_UP: /* Administrative state DOWN */
+ case NETDEV_DOWN: /* Administrative state UP */
+ case NETDEV_CHANGE: /* Link (carrier) state changes */
+ old_operstate = hsr_priv->dev->operstate;
+ hsr_set_carrier(hsr_priv->dev, slave, other_slave);
+ /* netif_stacked_transfer_operstate() cannot be used here since
+ * it doesn't set IF_OPER_LOWERLAYERDOWN (?)
+ */
+ hsr_set_operstate(hsr_priv->dev, slave, other_slave);
+ hsr_check_announce(hsr_priv->dev, old_operstate);
+ break;
+ case NETDEV_CHANGEADDR:
+
+ /* This should not happen since there's no ndo_set_mac_address()
+ * for HSR devices - i.e. not supported.
+ */
+ if (dev == hsr_priv->dev)
+ break;
+
+ if (dev == hsr_priv->slave[0])
+ memcpy(hsr_priv->dev->dev_addr,
+ hsr_priv->slave[0]->dev_addr, ETH_ALEN);
+
+ /* Make sure we recognize frames from ourselves in hsr_rcv() */
+ res = hsr_create_self_node(&hsr_priv->self_node_db,
+ hsr_priv->dev->dev_addr,
+ hsr_priv->slave[1] ?
+ hsr_priv->slave[1]->dev_addr :
+ hsr_priv->dev->dev_addr);
+ if (res)
+ netdev_warn(hsr_priv->dev,
+ "Could not update HSR node address.\n");
+
+ if (dev == hsr_priv->slave[0])
+ call_netdevice_notifiers(NETDEV_CHANGEADDR, hsr_priv->dev);
+ break;
+ case NETDEV_CHANGEMTU:
+ if (dev == hsr_priv->dev)
+ break; /* Handled in ndo_change_mtu() */
+ mtu_max = hsr_get_max_mtu(hsr_priv);
+ if (hsr_priv->dev->mtu > mtu_max)
+ dev_set_mtu(hsr_priv->dev, mtu_max);
+ break;
+ case NETDEV_UNREGISTER:
+ if (dev == hsr_priv->slave[0])
+ hsr_priv->slave[0] = NULL;
+ if (dev == hsr_priv->slave[1])
+ hsr_priv->slave[1] = NULL;
+
+ /* There should really be a way to set a new slave device... */
+
+ break;
+ case NETDEV_PRE_TYPE_CHANGE:
+ /* HSR works only on Ethernet devices. Refuse slave to change
+ * its type.
+ */
+ return NOTIFY_BAD;
+ }
+
+ return NOTIFY_DONE;
+}
+
+
+static struct timer_list prune_timer;
+
+static void prune_nodes_all(unsigned long data)
+{
+ struct hsr_priv *hsr_priv;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(hsr_priv, &hsr_list, hsr_list)
+ hsr_prune_nodes(hsr_priv);
+ rcu_read_unlock();
+
+ prune_timer.expires = jiffies + msecs_to_jiffies(PRUNE_PERIOD);
+ add_timer(&prune_timer);
+}
+
+
+static struct sk_buff *hsr_pull_tag(struct sk_buff *skb)
+{
+ struct hsr_tag *hsr_tag;
+ struct sk_buff *skb2;
+
+ skb2 = skb_share_check(skb, GFP_ATOMIC);
+ if (unlikely(!skb2))
+ goto err_free;
+ skb = skb2;
+
+ if (unlikely(!pskb_may_pull(skb, HSR_TAGLEN)))
+ goto err_free;
+
+ hsr_tag = (struct hsr_tag *) skb->data;
+ skb->protocol = hsr_tag->encap_proto;
+ skb_pull(skb, HSR_TAGLEN);
+
+ return skb;
+
+err_free:
+ kfree_skb(skb);
+ return NULL;
+}
+
+
+/* The uses I can see for these HSR supervision frames are:
+ * 1) Use the frames that are sent after node initialization ("HSR_TLV.Type =
+ * 22") to reset any sequence_nr counters belonging to that node. Useful if
+ * the other node's counter has been reset for some reason.
+ * --
+ * Or not - resetting the counter and bridging the frame would create a
+ * loop, unfortunately.
+ *
+ * 2) Use the LifeCheck frames to detect ring breaks. I.e. if no LifeCheck
+ * frame is received from a particular node, we know something is wrong.
+ * We just register these (as with normal frames) and throw them away.
+ *
+ * 3) Allow different MAC addresses for the two slave interfaces, using the
+ * MacAddressA field.
+ */
+static bool is_supervision_frame(struct hsr_priv *hsr_priv, struct sk_buff *skb)
+{
+ struct hsr_sup_tag *hsr_stag;
+
+ if (!ether_addr_equal(eth_hdr(skb)->h_dest,
+ hsr_priv->sup_multicast_addr))
+ return false;
+
+ hsr_stag = (struct hsr_sup_tag *) skb->data;
+ if (get_hsr_stag_path(hsr_stag) != 0x0f)
+ return false;
+ if ((hsr_stag->HSR_TLV_Type != HSR_TLV_ANNOUNCE) &&
+ (hsr_stag->HSR_TLV_Type != HSR_TLV_LIFE_CHECK))
+ return false;
+ if (hsr_stag->HSR_TLV_Length != 12)
+ return false;
+
+ return true;
+}
+
+
+/* Implementation somewhat according to IEC-62439-3, p. 43
+ */
+static int hsr_rcv(struct sk_buff *skb, struct net_device *dev,
+ struct packet_type *pt, struct net_device *orig_dev)
+{
+ struct hsr_priv *hsr_priv;
+ struct net_device *other_slave;
+ struct node_entry *node;
+ bool deliver_to_self;
+ struct sk_buff *skb_deliver;
+ enum hsr_dev_idx dev_in_idx, dev_other_idx;
+ bool dup_out;
+ int ret;
+
+ hsr_priv = get_hsr_master(dev);
+
+ if (!hsr_priv) {
+ /* Non-HSR-slave device 'dev' is connected to a HSR network */
+ kfree_skb(skb);
+ dev->stats.rx_errors++;
+ return NET_RX_SUCCESS;
+ }
+
+ if (dev == hsr_priv->slave[0]) {
+ dev_in_idx = HSR_DEV_SLAVE_A;
+ dev_other_idx = HSR_DEV_SLAVE_B;
+ } else {
+ dev_in_idx = HSR_DEV_SLAVE_B;
+ dev_other_idx = HSR_DEV_SLAVE_A;
+ }
+
+ node = hsr_find_node(&hsr_priv->self_node_db, skb);
+ if (node) {
+ /* Always kill frames sent by ourselves */
+ kfree_skb(skb);
+ return NET_RX_SUCCESS;
+ }
+
+ /* Is this frame a candidate for local reception? */
+ deliver_to_self = false;
+ if ((skb->pkt_type == PACKET_HOST) ||
+ (skb->pkt_type == PACKET_MULTICAST) ||
+ (skb->pkt_type == PACKET_BROADCAST))
+ deliver_to_self = true;
+ else if (ether_addr_equal(eth_hdr(skb)->h_dest,
+ hsr_priv->dev->dev_addr)) {
+ skb->pkt_type = PACKET_HOST;
+ deliver_to_self = true;
+ }
+
+
+ rcu_read_lock(); /* node_db */
+ node = hsr_find_node(&hsr_priv->node_db, skb);
+
+ if (is_supervision_frame(hsr_priv, skb)) {
+ skb_pull(skb, sizeof(struct hsr_sup_tag));
+ node = hsr_merge_node(hsr_priv, node, skb, dev_in_idx);
+ if (!node) {
+ rcu_read_unlock(); /* node_db */
+ kfree_skb(skb);
+ hsr_priv->dev->stats.rx_dropped++;
+ return NET_RX_DROP;
+ }
+ skb_push(skb, sizeof(struct hsr_sup_tag));
+ deliver_to_self = false;
+ }
+
+ if (!node) {
+ /* Source node unknown; this might be a HSR frame from
+ * another net (different multicast address). Ignore it.
+ */
+ rcu_read_unlock(); /* node_db */
+ kfree_skb(skb);
+ return NET_RX_SUCCESS;
+ }
+
+ /* Register ALL incoming frames as outgoing through the other interface.
+ * This allows us to register frames as incoming only if they are valid
+ * for the receiving interface, without using a specific counter for
+ * incoming frames.
+ */
+ dup_out = hsr_register_frame_out(node, dev_other_idx, skb);
+ if (!dup_out)
+ hsr_register_frame_in(node, dev_in_idx);
+
+ /* Forward this frame? */
+ if (!dup_out && (skb->pkt_type != PACKET_HOST))
+ other_slave = get_other_slave(hsr_priv, dev);
+ else
+ other_slave = NULL;
+
+ if (hsr_register_frame_out(node, HSR_DEV_MASTER, skb))
+ deliver_to_self = false;
+
+ rcu_read_unlock(); /* node_db */
+
+ if (!deliver_to_self && !other_slave) {
+ kfree_skb(skb);
+ /* Circulated frame; silently remove it. */
+ return NET_RX_SUCCESS;
+ }
+
+ skb_deliver = skb;
+ if (deliver_to_self && other_slave) {
+ /* skb_clone() is not enough since we will strip the hsr tag
+ * and do address substitution below
+ */
+ skb_deliver = pskb_copy(skb, GFP_ATOMIC);
+ if (!skb_deliver) {
+ deliver_to_self = false;
+ hsr_priv->dev->stats.rx_dropped++;
+ }
+ }
+
+ if (deliver_to_self) {
+ bool multicast_frame;
+
+ skb_deliver = hsr_pull_tag(skb_deliver);
+ if (!skb_deliver) {
+ hsr_priv->dev->stats.rx_dropped++;
+ goto forward;
+ }
+#if !defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
+ /* Move everything in the header that is after the HSR tag,
+ * to work around alignment problems caused by the 6-byte HSR
+ * tag. In practice, this removes/overwrites the HSR tag in
+ * the header and restores a "standard" packet.
+ */
+ memmove(skb_deliver->data - HSR_TAGLEN, skb_deliver->data,
+ skb_headlen(skb_deliver));
+
+ /* Adjust skb members so they correspond with the move above.
+ * This cannot possibly underflow skb->data since hsr_pull_tag()
+ * above succeeded.
+ * At this point in the protocol stack, the transport and
+ * network headers have not been set yet, and we haven't touched
+ * the mac header nor the head. So we only need to adjust data
+ * and tail:
+ */
+ skb_deliver->data -= HSR_TAGLEN;
+ skb_deliver->tail -= HSR_TAGLEN;
+#endif
+ skb_deliver->dev = hsr_priv->dev;
+ hsr_addr_subst_source(hsr_priv, skb_deliver);
+ multicast_frame = (skb_deliver->pkt_type == PACKET_MULTICAST);
+ ret = netif_rx(skb_deliver);
+ if (ret == NET_RX_DROP) {
+ hsr_priv->dev->stats.rx_dropped++;
+ } else {
+ hsr_priv->dev->stats.rx_packets++;
+ hsr_priv->dev->stats.rx_bytes += skb->len;
+ if (multicast_frame)
+ hsr_priv->dev->stats.multicast++;
+ }
+ }
+
+forward:
+ if (other_slave) {
+ skb_push(skb, ETH_HLEN);
+ skb->dev = other_slave;
+ dev_queue_xmit(skb);
+ }
+
+ return NET_RX_SUCCESS;
+}
+
+
+static struct packet_type hsr_pt __read_mostly = {
+ .type = htons(ETH_P_PRP),
+ .func = hsr_rcv,
+};
+
+static struct notifier_block hsr_nb = {
+ .notifier_call = hsr_netdev_notify, /* Slave event notifications */
+};
+
+
+static int __init hsr_init(void)
+{
+ int res;
+
+ BUILD_BUG_ON(sizeof(struct hsr_tag) != HSR_TAGLEN);
+
+ dev_add_pack(&hsr_pt);
+
+ init_timer(&prune_timer);
+ prune_timer.function = prune_nodes_all;
+ prune_timer.data = 0;
+ prune_timer.expires = jiffies + msecs_to_jiffies(PRUNE_PERIOD);
+ add_timer(&prune_timer);
+
+ register_netdevice_notifier(&hsr_nb);
+
+ res = hsr_netlink_init();
+
+ return res;
+}
+
+static void __exit hsr_exit(void)
+{
+ unregister_netdevice_notifier(&hsr_nb);
+ del_timer(&prune_timer);
+ hsr_netlink_exit();
+ dev_remove_pack(&hsr_pt);
+}
+
+module_init(hsr_init);
+module_exit(hsr_exit);
+MODULE_LICENSE("GPL");