// SPDX-License-Identifier: GPL-2.0 /* Copyright 2011-2014 Autronica Fire and Security AS * * Author(s): * 2011-2014 Arvid Brodin, arvid.brodin@alten.se * * 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" /* TODO: use hash lists for mac addresses (linux/jhash.h)? */ /* 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))) bool hsr_addr_is_self(struct hsr_priv *hsr, unsigned char *addr) { struct hsr_node *node; node = list_first_or_null_rcu(&hsr->self_node_db, struct hsr_node, mac_list); if (!node) { WARN_ONCE(1, "HSR: No self node\n"); return false; } if (ether_addr_equal(addr, node->macaddress_A)) return true; if (ether_addr_equal(addr, node->macaddress_B)) return true; return false; } /* Search for mac entry. Caller must hold rcu read lock. */ static struct hsr_node *find_node_by_addr_A(struct list_head *node_db, const unsigned char addr[ETH_ALEN]) { struct hsr_node *node; list_for_each_entry_rcu(node, node_db, mac_list) { if (ether_addr_equal(node->macaddress_A, addr)) 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 hsr_priv *hsr, unsigned char addr_a[ETH_ALEN], unsigned char addr_b[ETH_ALEN]) { struct list_head *self_node_db = &hsr->self_node_db; struct hsr_node *node, *oldnode; node = kmalloc(sizeof(*node), GFP_KERNEL); if (!node) return -ENOMEM; ether_addr_copy(node->macaddress_A, addr_a); ether_addr_copy(node->macaddress_B, addr_b); spin_lock_bh(&hsr->list_lock); oldnode = list_first_or_null_rcu(self_node_db, struct hsr_node, mac_list); if (oldnode) { list_replace_rcu(&oldnode->mac_list, &node->mac_list); spin_unlock_bh(&hsr->list_lock); kfree_rcu(oldnode, rcu_head); } else { list_add_tail_rcu(&node->mac_list, self_node_db); spin_unlock_bh(&hsr->list_lock); } return 0; } void hsr_del_self_node(struct hsr_priv *hsr) { struct list_head *self_node_db = &hsr->self_node_db; struct hsr_node *node; spin_lock_bh(&hsr->list_lock); node = list_first_or_null_rcu(self_node_db, struct hsr_node, mac_list); if (node) { list_del_rcu(&node->mac_list); kfree_rcu(node, rcu_head); } spin_unlock_bh(&hsr->list_lock); } void hsr_del_nodes(struct list_head *node_db) { struct hsr_node *node; struct hsr_node *tmp; list_for_each_entry_safe(node, tmp, node_db, mac_list) kfree(node); } /* Allocate an hsr_node and add it to node_db. 'addr' is the node's address_A; * seq_out is used to initialize filtering of outgoing duplicate frames * originating from the newly added node. */ static struct hsr_node *hsr_add_node(struct hsr_priv *hsr, struct list_head *node_db, unsigned char addr[], u16 seq_out) { struct hsr_node *new_node, *node; unsigned long now; int i; new_node = kzalloc(sizeof(*new_node), GFP_ATOMIC); if (!new_node) return NULL; ether_addr_copy(new_node->macaddress_A, addr); /* 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_PT_PORTS; i++) new_node->time_in[i] = now; for (i = 0; i < HSR_PT_PORTS; i++) new_node->seq_out[i] = seq_out; spin_lock_bh(&hsr->list_lock); list_for_each_entry_rcu(node, node_db, mac_list) { if (ether_addr_equal(node->macaddress_A, addr)) goto out; if (ether_addr_equal(node->macaddress_B, addr)) goto out; } list_add_tail_rcu(&new_node->mac_list, node_db); spin_unlock_bh(&hsr->list_lock); return new_node; out: spin_unlock_bh(&hsr->list_lock); kfree(new_node); return node; } /* Get the hsr_node from which 'skb' was sent. */ struct hsr_node *hsr_get_node(struct hsr_port *port, struct sk_buff *skb, bool is_sup) { struct list_head *node_db = &port->hsr->node_db; struct hsr_priv *hsr = port->hsr; struct hsr_node *node; struct ethhdr *ethhdr; u16 seq_out; 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->macaddress_A, ethhdr->h_source)) return node; if (ether_addr_equal(node->macaddress_B, ethhdr->h_source)) return node; } /* Everyone may create a node entry, connected node to a HSR device. */ if (ethhdr->h_proto == htons(ETH_P_PRP) || ethhdr->h_proto == htons(ETH_P_HSR)) { /* Use the existing sequence_nr from the tag as starting point * for filtering duplicate frames. */ seq_out = hsr_get_skb_sequence_nr(skb) - 1; } else { /* this is called also for frames from master port and * so warn only for non master ports */ if (port->type != HSR_PT_MASTER) WARN_ONCE(1, "%s: Non-HSR frame\n", __func__); seq_out = HSR_SEQNR_START; } return hsr_add_node(hsr, node_db, ethhdr->h_source, seq_out); } /* Use the Supervision frame's info about an eventual macaddress_B for merging * nodes that has previously had their macaddress_B registered as a separate * node. */ void hsr_handle_sup_frame(struct sk_buff *skb, struct hsr_node *node_curr, struct hsr_port *port_rcv) { struct hsr_priv *hsr = port_rcv->hsr; struct hsr_sup_payload *hsr_sp; struct hsr_node *node_real; struct list_head *node_db; struct ethhdr *ethhdr; int i; ethhdr = (struct ethhdr *)skb_mac_header(skb); /* Leave the ethernet header. */ skb_pull(skb, sizeof(struct ethhdr)); /* And leave the HSR tag. */ if (ethhdr->h_proto == htons(ETH_P_HSR)) skb_pull(skb, sizeof(struct hsr_tag)); /* And leave the HSR sup tag. */ skb_pull(skb, sizeof(struct hsr_sup_tag)); hsr_sp = (struct hsr_sup_payload *)skb->data; /* Merge node_curr (registered on macaddress_B) into node_real */ node_db = &port_rcv->hsr->node_db; node_real = find_node_by_addr_A(node_db, hsr_sp->macaddress_A); if (!node_real) /* No frame received from AddrA of this node yet */ node_real = hsr_add_node(hsr, node_db, hsr_sp->macaddress_A, HSR_SEQNR_START - 1); if (!node_real) goto done; /* No mem */ if (node_real == node_curr) /* Node has already been merged */ goto done; ether_addr_copy(node_real->macaddress_B, ethhdr->h_source); for (i = 0; i < HSR_PT_PORTS; i++) { if (!node_curr->time_in_stale[i] && time_after(node_curr->time_in[i], node_real->time_in[i])) { node_real->time_in[i] = node_curr->time_in[i]; node_real->time_in_stale[i] = node_curr->time_in_stale[i]; } if (seq_nr_after(node_curr->seq_out[i], node_real->seq_out[i])) node_real->seq_out[i] = node_curr->seq_out[i]; } node_real->addr_B_port = port_rcv->type; spin_lock_bh(&hsr->list_lock); list_del_rcu(&node_curr->mac_list); spin_unlock_bh(&hsr->list_lock); kfree_rcu(node_curr, rcu_head); done: skb_push(skb, sizeof(struct hsrv1_ethhdr_sp)); } /* '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 source * address with that node's "official" address (macaddress_A) so that upper * layers recognize where it came from. */ void hsr_addr_subst_source(struct hsr_node *node, struct sk_buff *skb) { if (!skb_mac_header_was_set(skb)) { WARN_ONCE(1, "%s: Mac header not set\n", __func__); return; } memcpy(ð_hdr(skb)->h_source, node->macaddress_A, ETH_ALEN); } /* 'skb' is a frame meant for another host. * 'port' is the outgoing interface * * 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_node *node_src, struct sk_buff *skb, struct hsr_port *port) { struct hsr_node *node_dst; if (!skb_mac_header_was_set(skb)) { WARN_ONCE(1, "%s: Mac header not set\n", __func__); return; } if (!is_unicast_ether_addr(eth_hdr(skb)->h_dest)) return; node_dst = find_node_by_addr_A(&port->hsr->node_db, eth_hdr(skb)->h_dest); if (!node_dst) { WARN_ONCE(1, "%s: Unknown node\n", __func__); return; } if (port->type != node_dst->addr_B_port) return; ether_addr_copy(eth_hdr(skb)->h_dest, node_dst->macaddress_B); } void hsr_register_frame_in(struct hsr_node *node, struct hsr_port *port, u16 sequence_nr) { /* Don't register incoming frames without a valid sequence number. This * ensures entries of restarted nodes gets pruned so that they can * re-register and resume communications. */ if (seq_nr_before(sequence_nr, node->seq_out[port->type])) return; node->time_in[port->type] = jiffies; node->time_in_stale[port->type] = 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 hsr_port *port, struct hsr_node *node, u16 sequence_nr) { if (seq_nr_before_or_eq(sequence_nr, node->seq_out[port->type])) return 1; node->seq_out[port->type] = sequence_nr; return 0; } static struct hsr_port *get_late_port(struct hsr_priv *hsr, struct hsr_node *node) { if (node->time_in_stale[HSR_PT_SLAVE_A]) return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A); if (node->time_in_stale[HSR_PT_SLAVE_B]) return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B); if (time_after(node->time_in[HSR_PT_SLAVE_B], node->time_in[HSR_PT_SLAVE_A] + msecs_to_jiffies(MAX_SLAVE_DIFF))) return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A); if (time_after(node->time_in[HSR_PT_SLAVE_A], node->time_in[HSR_PT_SLAVE_B] + msecs_to_jiffies(MAX_SLAVE_DIFF))) return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B); return NULL; } /* Remove stale sequence_nr records. Called by timer every * HSR_LIFE_CHECK_INTERVAL (two seconds or so). */ void hsr_prune_nodes(struct timer_list *t) { struct hsr_priv *hsr = from_timer(hsr, t, prune_timer); struct hsr_node *node; struct hsr_node *tmp; struct hsr_port *port; unsigned long timestamp; unsigned long time_a, time_b; spin_lock_bh(&hsr->list_lock); list_for_each_entry_safe(node, tmp, &hsr->node_db, mac_list) { /* Don't prune own node. Neither time_in[HSR_PT_SLAVE_A] * nor time_in[HSR_PT_SLAVE_B], will ever be updated for * the master port. Thus the master node will be repeatedly * pruned leading to packet loss. */ if (hsr_addr_is_self(hsr, node->macaddress_A)) continue; /* Shorthand */ time_a = node->time_in[HSR_PT_SLAVE_A]; time_b = node->time_in[HSR_PT_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_PT_SLAVE_A] = true; if (time_after(jiffies, time_b + MAX_JIFFY_OFFSET / 2)) node->time_in_stale[HSR_PT_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_PT_SLAVE_A] || (!node->time_in_stale[HSR_PT_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))) { rcu_read_lock(); port = get_late_port(hsr, node); if (port) hsr_nl_ringerror(hsr, node->macaddress_A, port); rcu_read_unlock(); } /* Prune old entries */ if (time_is_before_jiffies(timestamp + msecs_to_jiffies(HSR_NODE_FORGET_TIME))) { hsr_nl_nodedown(hsr, node->macaddress_A); list_del_rcu(&node->mac_list); /* Note that we need to free this entry later: */ kfree_rcu(node, rcu_head); } } spin_unlock_bh(&hsr->list_lock); /* Restart timer */ mod_timer(&hsr->prune_timer, jiffies + msecs_to_jiffies(PRUNE_PERIOD)); } void *hsr_get_next_node(struct hsr_priv *hsr, void *_pos, unsigned char addr[ETH_ALEN]) { struct hsr_node *node; if (!_pos) { node = list_first_or_null_rcu(&hsr->node_db, struct hsr_node, mac_list); if (node) ether_addr_copy(addr, node->macaddress_A); return node; } node = _pos; list_for_each_entry_continue_rcu(node, &hsr->node_db, mac_list) { ether_addr_copy(addr, node->macaddress_A); return node; } return NULL; } int hsr_get_node_data(struct hsr_priv *hsr, 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 hsr_node *node; struct hsr_port *port; unsigned long tdiff; rcu_read_lock(); node = find_node_by_addr_A(&hsr->node_db, addr); if (!node) { rcu_read_unlock(); return -ENOENT; /* No such entry */ } ether_addr_copy(addr_b, node->macaddress_B); tdiff = jiffies - node->time_in[HSR_PT_SLAVE_A]; if (node->time_in_stale[HSR_PT_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_PT_SLAVE_B]; if (node->time_in_stale[HSR_PT_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_PT_SLAVE_B]; *if2_seq = node->seq_out[HSR_PT_SLAVE_A]; if (node->addr_B_port != HSR_PT_NONE) { port = hsr_port_get_hsr(hsr, node->addr_B_port); *addr_b_ifindex = port->dev->ifindex; } else { *addr_b_ifindex = -1; } rcu_read_unlock(); return 0; }