500 lines
14 KiB
C
500 lines
14 KiB
C
/* Copyright 2011-2013 Autronica Fire and Security AS
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* Author(s):
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* 2011-2013 Arvid Brodin, arvid.brodin@xdin.com
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*
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* The HSR spec says never to forward the same frame twice on the same
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* interface. A frame is identified by its source MAC address and its HSR
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* sequence number. This code keeps track of senders and their sequence numbers
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* to allow filtering of duplicate frames, and to detect HSR ring errors.
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*/
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#include <linux/if_ether.h>
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#include <linux/etherdevice.h>
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#include <linux/slab.h>
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#include <linux/rculist.h>
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#include "hsr_main.h"
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#include "hsr_framereg.h"
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#include "hsr_netlink.h"
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struct node_entry {
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struct list_head mac_list;
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unsigned char MacAddressA[ETH_ALEN];
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unsigned char MacAddressB[ETH_ALEN];
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enum hsr_dev_idx AddrB_if; /* The local slave through which AddrB
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* frames are received from this node
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*/
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unsigned long time_in[HSR_MAX_SLAVE];
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bool time_in_stale[HSR_MAX_SLAVE];
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u16 seq_out[HSR_MAX_DEV];
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struct rcu_head rcu_head;
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};
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/* TODO: use hash lists for mac addresses (linux/jhash.h)? */
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/* Search for mac entry. Caller must hold rcu read lock.
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*/
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static struct node_entry *find_node_by_AddrA(struct list_head *node_db,
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const unsigned char addr[ETH_ALEN])
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{
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struct node_entry *node;
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list_for_each_entry_rcu(node, node_db, mac_list) {
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if (ether_addr_equal(node->MacAddressA, addr))
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return node;
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}
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return NULL;
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}
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/* Search for mac entry. Caller must hold rcu read lock.
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*/
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static struct node_entry *find_node_by_AddrB(struct list_head *node_db,
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const unsigned char addr[ETH_ALEN])
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{
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struct node_entry *node;
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list_for_each_entry_rcu(node, node_db, mac_list) {
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if (ether_addr_equal(node->MacAddressB, addr))
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return node;
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}
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return NULL;
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}
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/* Search for mac entry. Caller must hold rcu read lock.
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*/
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struct node_entry *hsr_find_node(struct list_head *node_db, struct sk_buff *skb)
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{
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struct node_entry *node;
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struct ethhdr *ethhdr;
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if (!skb_mac_header_was_set(skb))
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return NULL;
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ethhdr = (struct ethhdr *) skb_mac_header(skb);
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list_for_each_entry_rcu(node, node_db, mac_list) {
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if (ether_addr_equal(node->MacAddressA, ethhdr->h_source))
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return node;
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if (ether_addr_equal(node->MacAddressB, ethhdr->h_source))
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return node;
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}
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return NULL;
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}
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/* Helper for device init; the self_node_db is used in hsr_rcv() to recognize
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* frames from self that's been looped over the HSR ring.
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*/
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int hsr_create_self_node(struct list_head *self_node_db,
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unsigned char addr_a[ETH_ALEN],
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unsigned char addr_b[ETH_ALEN])
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{
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struct node_entry *node, *oldnode;
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node = kmalloc(sizeof(*node), GFP_KERNEL);
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if (!node)
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return -ENOMEM;
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memcpy(node->MacAddressA, addr_a, ETH_ALEN);
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memcpy(node->MacAddressB, addr_b, ETH_ALEN);
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rcu_read_lock();
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oldnode = list_first_or_null_rcu(self_node_db,
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struct node_entry, mac_list);
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if (oldnode) {
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list_replace_rcu(&oldnode->mac_list, &node->mac_list);
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rcu_read_unlock();
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synchronize_rcu();
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kfree(oldnode);
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} else {
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rcu_read_unlock();
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list_add_tail_rcu(&node->mac_list, self_node_db);
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}
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return 0;
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}
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/* Add/merge node to the database of nodes. 'skb' must contain an HSR
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* supervision frame.
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* - If the supervision header's MacAddressA field is not yet in the database,
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* this frame is from an hitherto unknown node - add it to the database.
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* - If the sender's MAC address is not the same as its MacAddressA address,
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* the node is using PICS_SUBS (address substitution). Record the sender's
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* address as the node's MacAddressB.
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*
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* This function needs to work even if the sender node has changed one of its
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* slaves' MAC addresses. In this case, there are four different cases described
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* by (Addr-changed, received-from) pairs as follows. Note that changing the
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* SlaveA address is equal to changing the node's own address:
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*
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* - (AddrB, SlaveB): The new AddrB will be recorded by PICS_SUBS code since
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* node == NULL.
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* - (AddrB, SlaveA): Will work as usual (the AddrB change won't be detected
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* from this frame).
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*
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* - (AddrA, SlaveB): The old node will be found. We need to detect this and
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* remove the node.
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* - (AddrA, SlaveA): A new node will be registered (non-PICS_SUBS at first).
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* The old one will be pruned after HSR_NODE_FORGET_TIME.
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*
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* We also need to detect if the sender's SlaveA and SlaveB cables have been
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* swapped.
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*/
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struct node_entry *hsr_merge_node(struct hsr_priv *hsr_priv,
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struct node_entry *node,
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struct sk_buff *skb,
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enum hsr_dev_idx dev_idx)
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{
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struct hsr_sup_payload *hsr_sp;
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struct hsr_ethhdr_sp *hsr_ethsup;
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int i;
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unsigned long now;
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hsr_ethsup = (struct hsr_ethhdr_sp *) skb_mac_header(skb);
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hsr_sp = (struct hsr_sup_payload *) skb->data;
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if (node && !ether_addr_equal(node->MacAddressA, hsr_sp->MacAddressA)) {
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/* Node has changed its AddrA, frame was received from SlaveB */
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list_del_rcu(&node->mac_list);
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kfree_rcu(node, rcu_head);
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node = NULL;
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}
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if (node && (dev_idx == node->AddrB_if) &&
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!ether_addr_equal(node->MacAddressB, hsr_ethsup->ethhdr.h_source)) {
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/* Cables have been swapped */
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list_del_rcu(&node->mac_list);
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kfree_rcu(node, rcu_head);
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node = NULL;
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}
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if (node && (dev_idx != node->AddrB_if) &&
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(node->AddrB_if != HSR_DEV_NONE) &&
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!ether_addr_equal(node->MacAddressA, hsr_ethsup->ethhdr.h_source)) {
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/* Cables have been swapped */
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list_del_rcu(&node->mac_list);
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kfree_rcu(node, rcu_head);
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node = NULL;
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}
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if (node)
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return node;
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node = find_node_by_AddrA(&hsr_priv->node_db, hsr_sp->MacAddressA);
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if (node) {
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/* Node is known, but frame was received from an unknown
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* address. Node is PICS_SUBS capable; merge its AddrB.
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*/
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memcpy(node->MacAddressB, hsr_ethsup->ethhdr.h_source, ETH_ALEN);
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node->AddrB_if = dev_idx;
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return node;
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}
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node = kzalloc(sizeof(*node), GFP_ATOMIC);
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if (!node)
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return NULL;
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memcpy(node->MacAddressA, hsr_sp->MacAddressA, ETH_ALEN);
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memcpy(node->MacAddressB, hsr_ethsup->ethhdr.h_source, ETH_ALEN);
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if (!ether_addr_equal(hsr_sp->MacAddressA, hsr_ethsup->ethhdr.h_source))
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node->AddrB_if = dev_idx;
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else
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node->AddrB_if = HSR_DEV_NONE;
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/* We are only interested in time diffs here, so use current jiffies
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* as initialization. (0 could trigger an spurious ring error warning).
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*/
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now = jiffies;
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for (i = 0; i < HSR_MAX_SLAVE; i++)
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node->time_in[i] = now;
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for (i = 0; i < HSR_MAX_DEV; i++)
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node->seq_out[i] = ntohs(hsr_ethsup->hsr_sup.sequence_nr) - 1;
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list_add_tail_rcu(&node->mac_list, &hsr_priv->node_db);
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return node;
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}
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/* 'skb' is a frame meant for this host, that is to be passed to upper layers.
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*
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* If the frame was sent by a node's B interface, replace the sender
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* address with that node's "official" address (MacAddressA) so that upper
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* layers recognize where it came from.
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*/
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void hsr_addr_subst_source(struct hsr_priv *hsr_priv, struct sk_buff *skb)
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{
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struct ethhdr *ethhdr;
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struct node_entry *node;
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if (!skb_mac_header_was_set(skb)) {
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WARN_ONCE(1, "%s: Mac header not set\n", __func__);
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return;
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}
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ethhdr = (struct ethhdr *) skb_mac_header(skb);
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rcu_read_lock();
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node = find_node_by_AddrB(&hsr_priv->node_db, ethhdr->h_source);
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if (node)
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memcpy(ethhdr->h_source, node->MacAddressA, ETH_ALEN);
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rcu_read_unlock();
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}
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/* 'skb' is a frame meant for another host.
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* 'hsr_dev_idx' is the HSR index of the outgoing device
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*
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* Substitute the target (dest) MAC address if necessary, so the it matches the
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* recipient interface MAC address, regardless of whether that is the
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* recipient's A or B interface.
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* This is needed to keep the packets flowing through switches that learn on
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* which "side" the different interfaces are.
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*/
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void hsr_addr_subst_dest(struct hsr_priv *hsr_priv, struct ethhdr *ethhdr,
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enum hsr_dev_idx dev_idx)
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{
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struct node_entry *node;
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rcu_read_lock();
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node = find_node_by_AddrA(&hsr_priv->node_db, ethhdr->h_dest);
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if (node && (node->AddrB_if == dev_idx))
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memcpy(ethhdr->h_dest, node->MacAddressB, ETH_ALEN);
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rcu_read_unlock();
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}
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/* seq_nr_after(a, b) - return true if a is after (higher in sequence than) b,
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* false otherwise.
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*/
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static bool seq_nr_after(u16 a, u16 b)
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{
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/* Remove inconsistency where
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* seq_nr_after(a, b) == seq_nr_before(a, b)
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*/
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if ((int) b - a == 32768)
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return false;
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return (((s16) (b - a)) < 0);
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}
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#define seq_nr_before(a, b) seq_nr_after((b), (a))
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#define seq_nr_after_or_eq(a, b) (!seq_nr_before((a), (b)))
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#define seq_nr_before_or_eq(a, b) (!seq_nr_after((a), (b)))
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void hsr_register_frame_in(struct node_entry *node, enum hsr_dev_idx dev_idx)
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{
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if ((dev_idx < 0) || (dev_idx >= HSR_MAX_DEV)) {
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WARN_ONCE(1, "%s: Invalid dev_idx (%d)\n", __func__, dev_idx);
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return;
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}
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node->time_in[dev_idx] = jiffies;
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node->time_in_stale[dev_idx] = false;
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}
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/* 'skb' is a HSR Ethernet frame (with a HSR tag inserted), with a valid
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* ethhdr->h_source address and skb->mac_header set.
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*
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* Return:
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* 1 if frame can be shown to have been sent recently on this interface,
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* 0 otherwise, or
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* negative error code on error
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*/
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int hsr_register_frame_out(struct node_entry *node, enum hsr_dev_idx dev_idx,
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struct sk_buff *skb)
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{
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struct hsr_ethhdr *hsr_ethhdr;
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u16 sequence_nr;
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if ((dev_idx < 0) || (dev_idx >= HSR_MAX_DEV)) {
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WARN_ONCE(1, "%s: Invalid dev_idx (%d)\n", __func__, dev_idx);
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return -EINVAL;
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}
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if (!skb_mac_header_was_set(skb)) {
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WARN_ONCE(1, "%s: Mac header not set\n", __func__);
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return -EINVAL;
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}
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hsr_ethhdr = (struct hsr_ethhdr *) skb_mac_header(skb);
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sequence_nr = ntohs(hsr_ethhdr->hsr_tag.sequence_nr);
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if (seq_nr_before_or_eq(sequence_nr, node->seq_out[dev_idx]))
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return 1;
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node->seq_out[dev_idx] = sequence_nr;
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return 0;
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}
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static bool is_late(struct node_entry *node, enum hsr_dev_idx dev_idx)
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{
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enum hsr_dev_idx other;
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if (node->time_in_stale[dev_idx])
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return true;
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if (dev_idx == HSR_DEV_SLAVE_A)
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other = HSR_DEV_SLAVE_B;
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else
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other = HSR_DEV_SLAVE_A;
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if (node->time_in_stale[other])
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return false;
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if (time_after(node->time_in[other], node->time_in[dev_idx] +
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msecs_to_jiffies(MAX_SLAVE_DIFF)))
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return true;
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return false;
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}
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/* Remove stale sequence_nr records. Called by timer every
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* HSR_LIFE_CHECK_INTERVAL (two seconds or so).
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*/
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void hsr_prune_nodes(struct hsr_priv *hsr_priv)
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{
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struct node_entry *node;
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unsigned long timestamp;
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unsigned long time_a, time_b;
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rcu_read_lock();
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list_for_each_entry_rcu(node, &hsr_priv->node_db, mac_list) {
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/* Shorthand */
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time_a = node->time_in[HSR_DEV_SLAVE_A];
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time_b = node->time_in[HSR_DEV_SLAVE_B];
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/* Check for timestamps old enough to risk wrap-around */
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if (time_after(jiffies, time_a + MAX_JIFFY_OFFSET/2))
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node->time_in_stale[HSR_DEV_SLAVE_A] = true;
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if (time_after(jiffies, time_b + MAX_JIFFY_OFFSET/2))
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node->time_in_stale[HSR_DEV_SLAVE_B] = true;
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/* Get age of newest frame from node.
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* At least one time_in is OK here; nodes get pruned long
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* before both time_ins can get stale
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*/
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timestamp = time_a;
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if (node->time_in_stale[HSR_DEV_SLAVE_A] ||
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(!node->time_in_stale[HSR_DEV_SLAVE_B] &&
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time_after(time_b, time_a)))
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timestamp = time_b;
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/* Warn of ring error only as long as we get frames at all */
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if (time_is_after_jiffies(timestamp +
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msecs_to_jiffies(1.5*MAX_SLAVE_DIFF))) {
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if (is_late(node, HSR_DEV_SLAVE_A))
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hsr_nl_ringerror(hsr_priv, node->MacAddressA,
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HSR_DEV_SLAVE_A);
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else if (is_late(node, HSR_DEV_SLAVE_B))
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hsr_nl_ringerror(hsr_priv, node->MacAddressA,
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HSR_DEV_SLAVE_B);
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}
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/* Prune old entries */
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if (time_is_before_jiffies(timestamp +
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msecs_to_jiffies(HSR_NODE_FORGET_TIME))) {
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hsr_nl_nodedown(hsr_priv, node->MacAddressA);
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list_del_rcu(&node->mac_list);
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/* Note that we need to free this entry later: */
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kfree_rcu(node, rcu_head);
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}
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}
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rcu_read_unlock();
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}
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void *hsr_get_next_node(struct hsr_priv *hsr_priv, void *_pos,
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unsigned char addr[ETH_ALEN])
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{
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struct node_entry *node;
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if (!_pos) {
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node = list_first_or_null_rcu(&hsr_priv->node_db,
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struct node_entry, mac_list);
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if (node)
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memcpy(addr, node->MacAddressA, ETH_ALEN);
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return node;
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}
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node = _pos;
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list_for_each_entry_continue_rcu(node, &hsr_priv->node_db, mac_list) {
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memcpy(addr, node->MacAddressA, ETH_ALEN);
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return node;
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}
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return NULL;
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}
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int hsr_get_node_data(struct hsr_priv *hsr_priv,
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const unsigned char *addr,
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unsigned char addr_b[ETH_ALEN],
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unsigned int *addr_b_ifindex,
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int *if1_age,
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u16 *if1_seq,
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int *if2_age,
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u16 *if2_seq)
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{
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struct node_entry *node;
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unsigned long tdiff;
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rcu_read_lock();
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node = find_node_by_AddrA(&hsr_priv->node_db, addr);
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if (!node) {
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rcu_read_unlock();
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return -ENOENT; /* No such entry */
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}
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memcpy(addr_b, node->MacAddressB, ETH_ALEN);
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tdiff = jiffies - node->time_in[HSR_DEV_SLAVE_A];
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if (node->time_in_stale[HSR_DEV_SLAVE_A])
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*if1_age = INT_MAX;
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#if HZ <= MSEC_PER_SEC
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else if (tdiff > msecs_to_jiffies(INT_MAX))
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*if1_age = INT_MAX;
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#endif
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else
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*if1_age = jiffies_to_msecs(tdiff);
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tdiff = jiffies - node->time_in[HSR_DEV_SLAVE_B];
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if (node->time_in_stale[HSR_DEV_SLAVE_B])
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*if2_age = INT_MAX;
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#if HZ <= MSEC_PER_SEC
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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;
|
|
}
|