/* 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; memcpy(node->MacAddressA, addr_a, ETH_ALEN); memcpy(node->MacAddressB, addr_b, ETH_ALEN); 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; } static void node_entry_reclaim(struct rcu_head *rh) { kfree(container_of(rh, struct node_entry, rcu_head)); } /* 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); call_rcu(&node->rcu_head, node_entry_reclaim); 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); call_rcu(&node->rcu_head, node_entry_reclaim); 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); call_rcu(&node->rcu_head, node_entry_reclaim); 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. */ memcpy(node->MacAddressB, hsr_ethsup->ethhdr.h_source, ETH_ALEN); node->AddrB_if = dev_idx; return node; } node = kzalloc(sizeof(*node), GFP_ATOMIC); if (!node) return NULL; memcpy(node->MacAddressA, hsr_sp->MacAddressA, ETH_ALEN); memcpy(node->MacAddressB, hsr_ethsup->ethhdr.h_source, ETH_ALEN); 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) memcpy(ethhdr->h_source, node->MacAddressA, ETH_ALEN); 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)) memcpy(ethhdr->h_dest, node->MacAddressB, ETH_ALEN); 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_DEV)) { 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: */ call_rcu(&node->rcu_head, node_entry_reclaim); } } 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) memcpy(addr, node->MacAddressA, ETH_ALEN); return node; } node = _pos; list_for_each_entry_continue_rcu(node, &hsr_priv->node_db, mac_list) { memcpy(addr, node->MacAddressA, ETH_ALEN); 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 */ } memcpy(addr_b, node->MacAddressB, ETH_ALEN); 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; }