diff options
Diffstat (limited to 'net/hsr/hsr_main.c')
| -rw-r--r-- | net/hsr/hsr_main.c | 469 |
1 files changed, 469 insertions, 0 deletions
diff --git a/net/hsr/hsr_main.c b/net/hsr/hsr_main.c new file mode 100644 index 00000000000..3fee5218a69 --- /dev/null +++ b/net/hsr/hsr_main.c @@ -0,0 +1,469 @@ +/* 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]) + ether_addr_copy(hsr_priv->dev->dev_addr, + hsr_priv->slave[0]->dev_addr); + + /* 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_sync(&prune_timer); + hsr_netlink_exit(); + dev_remove_pack(&hsr_pt); +} + +module_init(hsr_init); +module_exit(hsr_exit); +MODULE_LICENSE("GPL"); |