net/hsr/hsr_framereg.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright 2011-2014 Autronica Fire and Security AS
   3  *
   4  * Author(s):
   5  *      2011-2014 Arvid Brodin, arvid.brodin@alten.se
   6  *
   7  * The HSR spec says never to forward the same frame twice on the same
   8  * interface. A frame is identified by its source MAC address and its HSR
   9  * sequence number. This code keeps track of senders and their sequence numbers
  10  * to allow filtering of duplicate frames, and to detect HSR ring errors.
  11  */
  12
  13 #include <linux/if_ether.h>
  14 #include <linux/etherdevice.h>
  15 #include <linux/slab.h>
  16 #include <linux/rculist.h>
  17 #include "hsr_main.h"
  18 #include "hsr_framereg.h"
  19 #include "hsr_netlink.h"
  20
  21 /*      TODO: use hash lists for mac addresses (linux/jhash.h)?    */
  22
  23 /* seq_nr_after(a, b) - return true if a is after (higher in sequence than) b,
  24  * false otherwise.
  25  */
  26 static bool seq_nr_after(u16 a, u16 b)
  27 {
  28         /* Remove inconsistency where
  29          * seq_nr_after(a, b) == seq_nr_before(a, b)
  30          */
  31         if ((int)b - a == 32768)
  32                 return false;
  33
  34         return (((s16)(b - a)) < 0);
  35 }
  36
  37 #define seq_nr_before(a, b)             seq_nr_after((b), (a))
  38 #define seq_nr_before_or_eq(a, b)       (!seq_nr_after((a), (b)))
  39
  40 bool hsr_addr_is_self(struct hsr_priv *hsr, unsigned char *addr)
  41 {
  42         struct hsr_node *node;
  43
  44         node = list_first_or_null_rcu(&hsr->self_node_db, struct hsr_node,
  45                                       mac_list);
  46         if (!node) {
  47                 WARN_ONCE(1, "HSR: No self node\n");
  48                 return false;
  49         }
  50
  51         if (ether_addr_equal(addr, node->macaddress_A))
  52                 return true;
  53         if (ether_addr_equal(addr, node->macaddress_B))
  54                 return true;
  55
  56         return false;
  57 }
  58
  59 /* Search for mac entry. Caller must hold rcu read lock.
  60  */
  61 static struct hsr_node *find_node_by_addr_A(struct list_head *node_db,
  62                                             const unsigned char addr[ETH_ALEN])
  63 {
  64         struct hsr_node *node;
  65
  66         list_for_each_entry_rcu(node, node_db, mac_list) {
  67                 if (ether_addr_equal(node->macaddress_A, addr))
  68                         return node;
  69         }
  70
  71         return NULL;
  72 }
  73
  74 /* Helper for device init; the self_node_db is used in hsr_rcv() to recognize
  75  * frames from self that's been looped over the HSR ring.
  76  */
  77 int hsr_create_self_node(struct hsr_priv *hsr,
  78                          unsigned char addr_a[ETH_ALEN],
  79                          unsigned char addr_b[ETH_ALEN])
  80 {
  81         struct list_head *self_node_db = &hsr->self_node_db;
  82         struct hsr_node *node, *oldnode;
  83
  84         node = kmalloc(sizeof(*node), GFP_KERNEL);
  85         if (!node)
  86                 return -ENOMEM;
  87
  88         ether_addr_copy(node->macaddress_A, addr_a);
  89         ether_addr_copy(node->macaddress_B, addr_b);
  90
  91         spin_lock_bh(&hsr->list_lock);
  92         oldnode = list_first_or_null_rcu(self_node_db,
  93                                          struct hsr_node, mac_list);
  94         if (oldnode) {
  95                 list_replace_rcu(&oldnode->mac_list, &node->mac_list);
  96                 spin_unlock_bh(&hsr->list_lock);
  97                 kfree_rcu(oldnode, rcu_head);
  98         } else {
  99                 list_add_tail_rcu(&node->mac_list, self_node_db);
 100                 spin_unlock_bh(&hsr->list_lock);
 101         }
 102
 103         return 0;
 104 }
 105
 106 void hsr_del_self_node(struct hsr_priv *hsr)
 107 {
 108         struct list_head *self_node_db = &hsr->self_node_db;
 109         struct hsr_node *node;
 110
 111         spin_lock_bh(&hsr->list_lock);
 112         node = list_first_or_null_rcu(self_node_db, struct hsr_node, mac_list);
 113         if (node) {
 114                 list_del_rcu(&node->mac_list);
 115                 kfree_rcu(node, rcu_head);
 116         }
 117         spin_unlock_bh(&hsr->list_lock);
 118 }
 119
 120 void hsr_del_nodes(struct list_head *node_db)
 121 {
 122         struct hsr_node *node;
 123         struct hsr_node *tmp;
 124
 125         list_for_each_entry_safe(node, tmp, node_db, mac_list)
 126                 kfree(node);
 127 }
 128
 129 /* Allocate an hsr_node and add it to node_db. 'addr' is the node's address_A;
 130  * seq_out is used to initialize filtering of outgoing duplicate frames
 131  * originating from the newly added node.
 132  */
 133 static struct hsr_node *hsr_add_node(struct hsr_priv *hsr,
 134                                      struct list_head *node_db,
 135                                      unsigned char addr[],
 136                                      u16 seq_out)
 137 {
 138         struct hsr_node *new_node, *node;
 139         unsigned long now;
 140         int i;
 141
 142         new_node = kzalloc(sizeof(*new_node), GFP_ATOMIC);
 143         if (!new_node)
 144                 return NULL;
 145
 146         ether_addr_copy(new_node->macaddress_A, addr);
 147
 148         /* We are only interested in time diffs here, so use current jiffies
 149          * as initialization. (0 could trigger an spurious ring error warning).
 150          */
 151         now = jiffies;
 152         for (i = 0; i < HSR_PT_PORTS; i++)
 153                 new_node->time_in[i] = now;
 154         for (i = 0; i < HSR_PT_PORTS; i++)
 155                 new_node->seq_out[i] = seq_out;
 156
 157         spin_lock_bh(&hsr->list_lock);
 158         list_for_each_entry_rcu(node, node_db, mac_list,
 159                                 lockdep_is_held(&hsr->list_lock)) {
 160                 if (ether_addr_equal(node->macaddress_A, addr))
 161                         goto out;
 162                 if (ether_addr_equal(node->macaddress_B, addr))
 163                         goto out;
 164         }
 165         list_add_tail_rcu(&new_node->mac_list, node_db);
 166         spin_unlock_bh(&hsr->list_lock);
 167         return new_node;
 168 out:
 169         spin_unlock_bh(&hsr->list_lock);
 170         kfree(new_node);
 171         return node;
 172 }
 173
 174 /* Get the hsr_node from which 'skb' was sent.
 175  */
 176 struct hsr_node *hsr_get_node(struct hsr_port *port, struct sk_buff *skb,
 177                               bool is_sup)
 178 {
 179         struct list_head *node_db = &port->hsr->node_db;
 180         struct hsr_priv *hsr = port->hsr;
 181         struct hsr_node *node;
 182         struct ethhdr *ethhdr;
 183         u16 seq_out;
 184
 185         if (!skb_mac_header_was_set(skb))
 186                 return NULL;
 187
 188         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 189
 190         list_for_each_entry_rcu(node, node_db, mac_list) {
 191                 if (ether_addr_equal(node->macaddress_A, ethhdr->h_source))
 192                         return node;
 193                 if (ether_addr_equal(node->macaddress_B, ethhdr->h_source))
 194                         return node;
 195         }
 196
 197         /* Everyone may create a node entry, connected node to a HSR device. */
 198
 199         if (ethhdr->h_proto == htons(ETH_P_PRP) ||
 200             ethhdr->h_proto == htons(ETH_P_HSR)) {
 201                 /* Use the existing sequence_nr from the tag as starting point
 202                  * for filtering duplicate frames.
 203                  */
 204                 seq_out = hsr_get_skb_sequence_nr(skb) - 1;
 205         } else {
 206                 /* this is called also for frames from master port and
 207                  * so warn only for non master ports
 208                  */
 209                 if (port->type != HSR_PT_MASTER)
 210                         WARN_ONCE(1, "%s: Non-HSR frame\n", __func__);
 211                 seq_out = HSR_SEQNR_START;
 212         }
 213
 214         return hsr_add_node(hsr, node_db, ethhdr->h_source, seq_out);
 215 }
 216
 217 /* Use the Supervision frame's info about an eventual macaddress_B for merging
 218  * nodes that has previously had their macaddress_B registered as a separate
 219  * node.
 220  */
 221 void hsr_handle_sup_frame(struct sk_buff *skb, struct hsr_node *node_curr,
 222                           struct hsr_port *port_rcv)
 223 {
 224         struct hsr_priv *hsr = port_rcv->hsr;
 225         struct hsr_sup_payload *hsr_sp;
 226         struct hsr_node *node_real;
 227         struct list_head *node_db;
 228         struct ethhdr *ethhdr;
 229         int i;
 230
 231         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 232
 233         /* Leave the ethernet header. */
 234         skb_pull(skb, sizeof(struct ethhdr));
 235
 236         /* And leave the HSR tag. */
 237         if (ethhdr->h_proto == htons(ETH_P_HSR))
 238                 skb_pull(skb, sizeof(struct hsr_tag));
 239
 240         /* And leave the HSR sup tag. */
 241         skb_pull(skb, sizeof(struct hsr_sup_tag));
 242
 243         hsr_sp = (struct hsr_sup_payload *)skb->data;
 244
 245         /* Merge node_curr (registered on macaddress_B) into node_real */
 246         node_db = &port_rcv->hsr->node_db;
 247         node_real = find_node_by_addr_A(node_db, hsr_sp->macaddress_A);
 248         if (!node_real)
 249                 /* No frame received from AddrA of this node yet */
 250                 node_real = hsr_add_node(hsr, node_db, hsr_sp->macaddress_A,
 251                                          HSR_SEQNR_START - 1);
 252         if (!node_real)
 253                 goto done; /* No mem */
 254         if (node_real == node_curr)
 255                 /* Node has already been merged */
 256                 goto done;
 257
 258         ether_addr_copy(node_real->macaddress_B, ethhdr->h_source);
 259         for (i = 0; i < HSR_PT_PORTS; i++) {
 260                 if (!node_curr->time_in_stale[i] &&
 261                     time_after(node_curr->time_in[i], node_real->time_in[i])) {
 262                         node_real->time_in[i] = node_curr->time_in[i];
 263                         node_real->time_in_stale[i] =
 264                                                 node_curr->time_in_stale[i];
 265                 }
 266                 if (seq_nr_after(node_curr->seq_out[i], node_real->seq_out[i]))
 267                         node_real->seq_out[i] = node_curr->seq_out[i];
 268         }
 269         node_real->addr_B_port = port_rcv->type;
 270
 271         spin_lock_bh(&hsr->list_lock);
 272         list_del_rcu(&node_curr->mac_list);
 273         spin_unlock_bh(&hsr->list_lock);
 274         kfree_rcu(node_curr, rcu_head);
 275
 276 done:
 277         skb_push(skb, sizeof(struct hsrv1_ethhdr_sp));
 278 }
 279
 280 /* 'skb' is a frame meant for this host, that is to be passed to upper layers.
 281  *
 282  * If the frame was sent by a node's B interface, replace the source
 283  * address with that node's "official" address (macaddress_A) so that upper
 284  * layers recognize where it came from.
 285  */
 286 void hsr_addr_subst_source(struct hsr_node *node, struct sk_buff *skb)
 287 {
 288         if (!skb_mac_header_was_set(skb)) {
 289                 WARN_ONCE(1, "%s: Mac header not set\n", __func__);
 290                 return;
 291         }
 292
 293         memcpy(&eth_hdr(skb)->h_source, node->macaddress_A, ETH_ALEN);
 294 }
 295
 296 /* 'skb' is a frame meant for another host.
 297  * 'port' is the outgoing interface
 298  *
 299  * Substitute the target (dest) MAC address if necessary, so the it matches the
 300  * recipient interface MAC address, regardless of whether that is the
 301  * recipient's A or B interface.
 302  * This is needed to keep the packets flowing through switches that learn on
 303  * which "side" the different interfaces are.
 304  */
 305 void hsr_addr_subst_dest(struct hsr_node *node_src, struct sk_buff *skb,
 306                          struct hsr_port *port)
 307 {
 308         struct hsr_node *node_dst;
 309
 310         if (!skb_mac_header_was_set(skb)) {
 311                 WARN_ONCE(1, "%s: Mac header not set\n", __func__);
 312                 return;
 313         }
 314
 315         if (!is_unicast_ether_addr(eth_hdr(skb)->h_dest))
 316                 return;
 317
 318         node_dst = find_node_by_addr_A(&port->hsr->node_db,
 319                                        eth_hdr(skb)->h_dest);
 320         if (!node_dst) {
 321                 if (net_ratelimit())
 322                         netdev_err(skb->dev, "%s: Unknown node\n", __func__);
 323                 return;
 324         }
 325         if (port->type != node_dst->addr_B_port)
 326                 return;
 327
 328         ether_addr_copy(eth_hdr(skb)->h_dest, node_dst->macaddress_B);
 329 }
 330
 331 void hsr_register_frame_in(struct hsr_node *node, struct hsr_port *port,
 332                            u16 sequence_nr)
 333 {
 334         /* Don't register incoming frames without a valid sequence number. This
 335          * ensures entries of restarted nodes gets pruned so that they can
 336          * re-register and resume communications.
 337          */
 338         if (seq_nr_before(sequence_nr, node->seq_out[port->type]))
 339                 return;
 340
 341         node->time_in[port->type] = jiffies;
 342         node->time_in_stale[port->type] = false;
 343 }
 344
 345 /* 'skb' is a HSR Ethernet frame (with a HSR tag inserted), with a valid
 346  * ethhdr->h_source address and skb->mac_header set.
 347  *
 348  * Return:
 349  *       1 if frame can be shown to have been sent recently on this interface,
 350  *       0 otherwise, or
 351  *       negative error code on error
 352  */
 353 int hsr_register_frame_out(struct hsr_port *port, struct hsr_node *node,
 354                            u16 sequence_nr)
 355 {
 356         if (seq_nr_before_or_eq(sequence_nr, node->seq_out[port->type]))
 357                 return 1;
 358
 359         node->seq_out[port->type] = sequence_nr;
 360         return 0;
 361 }
 362
 363 static struct hsr_port *get_late_port(struct hsr_priv *hsr,
 364                                       struct hsr_node *node)
 365 {
 366         if (node->time_in_stale[HSR_PT_SLAVE_A])
 367                 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
 368         if (node->time_in_stale[HSR_PT_SLAVE_B])
 369                 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
 370
 371         if (time_after(node->time_in[HSR_PT_SLAVE_B],
 372                        node->time_in[HSR_PT_SLAVE_A] +
 373                                         msecs_to_jiffies(MAX_SLAVE_DIFF)))
 374                 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
 375         if (time_after(node->time_in[HSR_PT_SLAVE_A],
 376                        node->time_in[HSR_PT_SLAVE_B] +
 377                                         msecs_to_jiffies(MAX_SLAVE_DIFF)))
 378                 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
 379
 380         return NULL;
 381 }
 382
 383 /* Remove stale sequence_nr records. Called by timer every
 384  * HSR_LIFE_CHECK_INTERVAL (two seconds or so).
 385  */
 386 void hsr_prune_nodes(struct timer_list *t)
 387 {
 388         struct hsr_priv *hsr = from_timer(hsr, t, prune_timer);
 389         struct hsr_node *node;
 390         struct hsr_node *tmp;
 391         struct hsr_port *port;
 392         unsigned long timestamp;
 393         unsigned long time_a, time_b;
 394
 395         spin_lock_bh(&hsr->list_lock);
 396         list_for_each_entry_safe(node, tmp, &hsr->node_db, mac_list) {
 397                 /* Don't prune own node. Neither time_in[HSR_PT_SLAVE_A]
 398                  * nor time_in[HSR_PT_SLAVE_B], will ever be updated for
 399                  * the master port. Thus the master node will be repeatedly
 400                  * pruned leading to packet loss.
 401                  */
 402                 if (hsr_addr_is_self(hsr, node->macaddress_A))
 403                         continue;
 404
 405                 /* Shorthand */
 406                 time_a = node->time_in[HSR_PT_SLAVE_A];
 407                 time_b = node->time_in[HSR_PT_SLAVE_B];
 408
 409                 /* Check for timestamps old enough to risk wrap-around */
 410                 if (time_after(jiffies, time_a + MAX_JIFFY_OFFSET / 2))
 411                         node->time_in_stale[HSR_PT_SLAVE_A] = true;
 412                 if (time_after(jiffies, time_b + MAX_JIFFY_OFFSET / 2))
 413                         node->time_in_stale[HSR_PT_SLAVE_B] = true;
 414
 415                 /* Get age of newest frame from node.
 416                  * At least one time_in is OK here; nodes get pruned long
 417                  * before both time_ins can get stale
 418                  */
 419                 timestamp = time_a;
 420                 if (node->time_in_stale[HSR_PT_SLAVE_A] ||
 421                     (!node->time_in_stale[HSR_PT_SLAVE_B] &&
 422                     time_after(time_b, time_a)))
 423                         timestamp = time_b;
 424
 425                 /* Warn of ring error only as long as we get frames at all */
 426                 if (time_is_after_jiffies(timestamp +
 427                                 msecs_to_jiffies(1.5 * MAX_SLAVE_DIFF))) {
 428                         rcu_read_lock();
 429                         port = get_late_port(hsr, node);
 430                         if (port)
 431                                 hsr_nl_ringerror(hsr, node->macaddress_A, port);
 432                         rcu_read_unlock();
 433                 }
 434
 435                 /* Prune old entries */
 436                 if (time_is_before_jiffies(timestamp +
 437                                 msecs_to_jiffies(HSR_NODE_FORGET_TIME))) {
 438                         hsr_nl_nodedown(hsr, node->macaddress_A);
 439                         list_del_rcu(&node->mac_list);
 440                         /* Note that we need to free this entry later: */
 441                         kfree_rcu(node, rcu_head);
 442                 }
 443         }
 444         spin_unlock_bh(&hsr->list_lock);
 445
 446         /* Restart timer */
 447         mod_timer(&hsr->prune_timer,
 448                   jiffies + msecs_to_jiffies(PRUNE_PERIOD));
 449 }
 450
 451 void *hsr_get_next_node(struct hsr_priv *hsr, void *_pos,
 452                         unsigned char addr[ETH_ALEN])
 453 {
 454         struct hsr_node *node;
 455
 456         if (!_pos) {
 457                 node = list_first_or_null_rcu(&hsr->node_db,
 458                                               struct hsr_node, mac_list);
 459                 if (node)
 460                         ether_addr_copy(addr, node->macaddress_A);
 461                 return node;
 462         }
 463
 464         node = _pos;
 465         list_for_each_entry_continue_rcu(node, &hsr->node_db, mac_list) {
 466                 ether_addr_copy(addr, node->macaddress_A);
 467                 return node;
 468         }
 469
 470         return NULL;
 471 }
 472
 473 int hsr_get_node_data(struct hsr_priv *hsr,
 474                       const unsigned char *addr,
 475                       unsigned char addr_b[ETH_ALEN],
 476                       unsigned int *addr_b_ifindex,
 477                       int *if1_age,
 478                       u16 *if1_seq,
 479                       int *if2_age,
 480                       u16 *if2_seq)
 481 {
 482         struct hsr_node *node;
 483         struct hsr_port *port;
 484         unsigned long tdiff;
 485
 486         node = find_node_by_addr_A(&hsr->node_db, addr);
 487         if (!node)
 488                 return -ENOENT;
 489
 490         ether_addr_copy(addr_b, node->macaddress_B);
 491
 492         tdiff = jiffies - node->time_in[HSR_PT_SLAVE_A];
 493         if (node->time_in_stale[HSR_PT_SLAVE_A])
 494                 *if1_age = INT_MAX;
 495 #if HZ <= MSEC_PER_SEC
 496         else if (tdiff > msecs_to_jiffies(INT_MAX))
 497                 *if1_age = INT_MAX;
 498 #endif
 499         else
 500                 *if1_age = jiffies_to_msecs(tdiff);
 501
 502         tdiff = jiffies - node->time_in[HSR_PT_SLAVE_B];
 503         if (node->time_in_stale[HSR_PT_SLAVE_B])
 504                 *if2_age = INT_MAX;
 505 #if HZ <= MSEC_PER_SEC
 506         else if (tdiff > msecs_to_jiffies(INT_MAX))
 507                 *if2_age = INT_MAX;
 508 #endif
 509         else
 510                 *if2_age = jiffies_to_msecs(tdiff);
 511
 512         /* Present sequence numbers as if they were incoming on interface */
 513         *if1_seq = node->seq_out[HSR_PT_SLAVE_B];
 514         *if2_seq = node->seq_out[HSR_PT_SLAVE_A];
 515
 516         if (node->addr_B_port != HSR_PT_NONE) {
 517                 port = hsr_port_get_hsr(hsr, node->addr_B_port);
 518                 *addr_b_ifindex = port->dev->ifindex;
 519         } else {
 520                 *addr_b_ifindex = -1;
 521         }
 522
 523         return 0;
 524 }