diff options
Diffstat (limited to 'net/hsr/hsr_framereg.c')
| -rw-r--r-- | net/hsr/hsr_framereg.c | 499 |
1 files changed, 499 insertions, 0 deletions
diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c new file mode 100644 index 00000000000..83e58449366 --- /dev/null +++ b/net/hsr/hsr_framereg.c @@ -0,0 +1,499 @@ +/* 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; + + 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 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; +} + + +/* 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); + kfree_rcu(node, rcu_head); + 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); + kfree_rcu(node, rcu_head); + 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); + kfree_rcu(node, rcu_head); + 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. + */ + ether_addr_copy(node->MacAddressB, hsr_ethsup->ethhdr.h_source); + node->AddrB_if = dev_idx; + return node; + } + + node = kzalloc(sizeof(*node), GFP_ATOMIC); + if (!node) + return NULL; + + ether_addr_copy(node->MacAddressA, hsr_sp->MacAddressA); + ether_addr_copy(node->MacAddressB, hsr_ethsup->ethhdr.h_source); + 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) + ether_addr_copy(ethhdr->h_source, node->MacAddressA); + 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)) + ether_addr_copy(ethhdr->h_dest, node->MacAddressB); + 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_SLAVE)) { + 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: */ + kfree_rcu(node, rcu_head); + } + } + 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) + ether_addr_copy(addr, node->MacAddressA); + return node; + } + + node = _pos; + list_for_each_entry_continue_rcu(node, &hsr_priv->node_db, mac_list) { + ether_addr_copy(addr, node->MacAddressA); + 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 */ + } + + ether_addr_copy(addr_b, node->MacAddressB); + + 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; +} |