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  * Same code handles filtering of duplicates for PRP as well.
  12  */
  13
  14 #include <linux/if_ether.h>
  15 #include <linux/etherdevice.h>
  16 #include <linux/slab.h>
  17 #include <linux/rculist.h>
  18 #include "hsr_main.h"
  19 #include "hsr_framereg.h"
  20 #include "hsr_netlink.h"
  21
  22 /*      TODO: use hash lists for mac addresses (linux/jhash.h)?    */
  23
  24 /* seq_nr_after(a, b) - return true if a is after (higher in sequence than) b,
  25  * false otherwise.
  26  */
  27 static bool seq_nr_after(u16 a, u16 b)
  28 {
  29         /* Remove inconsistency where
  30          * seq_nr_after(a, b) == seq_nr_before(a, b)
  31          */
  32         if ((int)b - a == 32768)
  33                 return false;
  34
  35         return (((s16)(b - a)) < 0);
  36 }
  37
  38 #define seq_nr_before(a, b)             seq_nr_after((b), (a))
  39 #define seq_nr_before_or_eq(a, b)       (!seq_nr_after((a), (b)))
  40
  41 bool hsr_addr_is_self(struct hsr_priv *hsr, unsigned char *addr)
  42 {
  43         struct hsr_node *node;
  44
  45         node = list_first_or_null_rcu(&hsr->self_node_db, struct hsr_node,
  46                                       mac_list);
  47         if (!node) {
  48                 WARN_ONCE(1, "HSR: No self node\n");
  49                 return false;
  50         }
  51
  52         if (ether_addr_equal(addr, node->macaddress_A))
  53                 return true;
  54         if (ether_addr_equal(addr, node->macaddress_B))
  55                 return true;
  56
  57         return false;
  58 }
  59
  60 /* Search for mac entry. Caller must hold rcu read lock.
  61  */
  62 static struct hsr_node *find_node_by_addr_A(struct list_head *node_db,
  63                                             const unsigned char addr[ETH_ALEN])
  64 {
  65         struct hsr_node *node;
  66
  67         list_for_each_entry_rcu(node, node_db, mac_list) {
  68                 if (ether_addr_equal(node->macaddress_A, addr))
  69                         return node;
  70         }
  71
  72         return NULL;
  73 }
  74
  75 /* Helper for device init; the self_node_db is used in hsr_rcv() to recognize
  76  * frames from self that's been looped over the HSR ring.
  77  */
  78 int hsr_create_self_node(struct hsr_priv *hsr,
  79                          unsigned char addr_a[ETH_ALEN],
  80                          unsigned char addr_b[ETH_ALEN])
  81 {
  82         struct list_head *self_node_db = &hsr->self_node_db;
  83         struct hsr_node *node, *oldnode;
  84
  85         node = kmalloc(sizeof(*node), GFP_KERNEL);
  86         if (!node)
  87                 return -ENOMEM;
  88
  89         ether_addr_copy(node->macaddress_A, addr_a);
  90         ether_addr_copy(node->macaddress_B, addr_b);
  91
  92         spin_lock_bh(&hsr->list_lock);
  93         oldnode = list_first_or_null_rcu(self_node_db,
  94                                          struct hsr_node, mac_list);
  95         if (oldnode) {
  96                 list_replace_rcu(&oldnode->mac_list, &node->mac_list);
  97                 spin_unlock_bh(&hsr->list_lock);
  98                 kfree_rcu(oldnode, rcu_head);
  99         } else {
 100                 list_add_tail_rcu(&node->mac_list, self_node_db);
 101                 spin_unlock_bh(&hsr->list_lock);
 102         }
 103
 104         return 0;
 105 }
 106
 107 void hsr_del_self_node(struct hsr_priv *hsr)
 108 {
 109         struct list_head *self_node_db = &hsr->self_node_db;
 110         struct hsr_node *node;
 111
 112         spin_lock_bh(&hsr->list_lock);
 113         node = list_first_or_null_rcu(self_node_db, struct hsr_node, mac_list);
 114         if (node) {
 115                 list_del_rcu(&node->mac_list);
 116                 kfree_rcu(node, rcu_head);
 117         }
 118         spin_unlock_bh(&hsr->list_lock);
 119 }
 120
 121 void hsr_del_nodes(struct list_head *node_db)
 122 {
 123         struct hsr_node *node;
 124         struct hsr_node *tmp;
 125
 126         list_for_each_entry_safe(node, tmp, node_db, mac_list)
 127                 kfree(node);
 128 }
 129
 130 void prp_handle_san_frame(bool san, enum hsr_port_type port,
 131                           struct hsr_node *node)
 132 {
 133         /* Mark if the SAN node is over LAN_A or LAN_B */
 134         if (port == HSR_PT_SLAVE_A) {
 135                 node->san_a = true;
 136                 return;
 137         }
 138
 139         if (port == HSR_PT_SLAVE_B)
 140                 node->san_b = true;
 141 }
 142
 143 /* Allocate an hsr_node and add it to node_db. 'addr' is the node's address_A;
 144  * seq_out is used to initialize filtering of outgoing duplicate frames
 145  * originating from the newly added node.
 146  */
 147 static struct hsr_node *hsr_add_node(struct hsr_priv *hsr,
 148                                      struct list_head *node_db,
 149                                      unsigned char addr[],
 150                                      u16 seq_out, bool san,
 151                                      enum hsr_port_type rx_port)
 152 {
 153         struct hsr_node *new_node, *node;
 154         unsigned long now;
 155         int i;
 156
 157         new_node = kzalloc(sizeof(*new_node), GFP_ATOMIC);
 158         if (!new_node)
 159                 return NULL;
 160
 161         ether_addr_copy(new_node->macaddress_A, addr);
 162
 163         /* We are only interested in time diffs here, so use current jiffies
 164          * as initialization. (0 could trigger an spurious ring error warning).
 165          */
 166         now = jiffies;
 167         for (i = 0; i < HSR_PT_PORTS; i++)
 168                 new_node->time_in[i] = now;
 169         for (i = 0; i < HSR_PT_PORTS; i++)
 170                 new_node->seq_out[i] = seq_out;
 171
 172         if (san && hsr->proto_ops->handle_san_frame)
 173                 hsr->proto_ops->handle_san_frame(san, rx_port, new_node);
 174
 175         spin_lock_bh(&hsr->list_lock);
 176         list_for_each_entry_rcu(node, node_db, mac_list,
 177                                 lockdep_is_held(&hsr->list_lock)) {
 178                 if (ether_addr_equal(node->macaddress_A, addr))
 179                         goto out;
 180                 if (ether_addr_equal(node->macaddress_B, addr))
 181                         goto out;
 182         }
 183         list_add_tail_rcu(&new_node->mac_list, node_db);
 184         spin_unlock_bh(&hsr->list_lock);
 185         return new_node;
 186 out:
 187         spin_unlock_bh(&hsr->list_lock);
 188         kfree(new_node);
 189         return node;
 190 }
 191
 192 void prp_update_san_info(struct hsr_node *node, bool is_sup)
 193 {
 194         if (!is_sup)
 195                 return;
 196
 197         node->san_a = false;
 198         node->san_b = false;
 199 }
 200
 201 /* Get the hsr_node from which 'skb' was sent.
 202  */
 203 struct hsr_node *hsr_get_node(struct hsr_port *port, struct list_head *node_db,
 204                               struct sk_buff *skb, bool is_sup,
 205                               enum hsr_port_type rx_port)
 206 {
 207         struct hsr_priv *hsr = port->hsr;
 208         struct hsr_node *node;
 209         struct ethhdr *ethhdr;
 210         struct prp_rct *rct;
 211         bool san = false;
 212         u16 seq_out;
 213
 214         if (!skb_mac_header_was_set(skb))
 215                 return NULL;
 216
 217         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 218
 219         list_for_each_entry_rcu(node, node_db, mac_list) {
 220                 if (ether_addr_equal(node->macaddress_A, ethhdr->h_source)) {
 221                         if (hsr->proto_ops->update_san_info)
 222                                 hsr->proto_ops->update_san_info(node, is_sup);
 223                         return node;
 224                 }
 225                 if (ether_addr_equal(node->macaddress_B, ethhdr->h_source)) {
 226                         if (hsr->proto_ops->update_san_info)
 227                                 hsr->proto_ops->update_san_info(node, is_sup);
 228                         return node;
 229                 }
 230         }
 231
 232         /* Everyone may create a node entry, connected node to a HSR/PRP
 233          * device.
 234          */
 235         if (ethhdr->h_proto == htons(ETH_P_PRP) ||
 236             ethhdr->h_proto == htons(ETH_P_HSR)) {
 237                 /* Use the existing sequence_nr from the tag as starting point
 238                  * for filtering duplicate frames.
 239                  */
 240                 seq_out = hsr_get_skb_sequence_nr(skb) - 1;
 241         } else {
 242                 rct = skb_get_PRP_rct(skb);
 243                 if (rct && prp_check_lsdu_size(skb, rct, is_sup)) {
 244                         seq_out = prp_get_skb_sequence_nr(rct);
 245                 } else {
 246                         if (rx_port != HSR_PT_MASTER)
 247                                 san = true;
 248                         seq_out = HSR_SEQNR_START;
 249                 }
 250         }
 251
 252         return hsr_add_node(hsr, node_db, ethhdr->h_source, seq_out,
 253                             san, rx_port);
 254 }
 255
 256 /* Use the Supervision frame's info about an eventual macaddress_B for merging
 257  * nodes that has previously had their macaddress_B registered as a separate
 258  * node.
 259  */
 260 void hsr_handle_sup_frame(struct hsr_frame_info *frame)
 261 {
 262         struct hsr_node *node_curr = frame->node_src;
 263         struct hsr_port *port_rcv = frame->port_rcv;
 264         struct hsr_priv *hsr = port_rcv->hsr;
 265         struct hsr_sup_payload *hsr_sp;
 266         struct hsr_node *node_real;
 267         struct sk_buff *skb = NULL;
 268         struct list_head *node_db;
 269         struct ethhdr *ethhdr;
 270         int i;
 271
 272         /* Here either frame->skb_hsr or frame->skb_prp should be
 273          * valid as supervision frame always will have protocol
 274          * header info.
 275          */
 276         if (frame->skb_hsr)
 277                 skb = frame->skb_hsr;
 278         else if (frame->skb_prp)
 279                 skb = frame->skb_prp;
 280         if (!skb)
 281                 return;
 282
 283         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 284
 285         /* Leave the ethernet header. */
 286         skb_pull(skb, sizeof(struct ethhdr));
 287
 288         /* And leave the HSR tag. */
 289         if (ethhdr->h_proto == htons(ETH_P_HSR))
 290                 skb_pull(skb, sizeof(struct hsr_tag));
 291
 292         /* And leave the HSR sup tag. */
 293         skb_pull(skb, sizeof(struct hsr_sup_tag));
 294
 295         hsr_sp = (struct hsr_sup_payload *)skb->data;
 296
 297         /* Merge node_curr (registered on macaddress_B) into node_real */
 298         node_db = &port_rcv->hsr->node_db;
 299         node_real = find_node_by_addr_A(node_db, hsr_sp->macaddress_A);
 300         if (!node_real)
 301                 /* No frame received from AddrA of this node yet */
 302                 node_real = hsr_add_node(hsr, node_db, hsr_sp->macaddress_A,
 303                                          HSR_SEQNR_START - 1, true,
 304                                          port_rcv->type);
 305         if (!node_real)
 306                 goto done; /* No mem */
 307         if (node_real == node_curr)
 308                 /* Node has already been merged */
 309                 goto done;
 310
 311         ether_addr_copy(node_real->macaddress_B, ethhdr->h_source);
 312         for (i = 0; i < HSR_PT_PORTS; i++) {
 313                 if (!node_curr->time_in_stale[i] &&
 314                     time_after(node_curr->time_in[i], node_real->time_in[i])) {
 315                         node_real->time_in[i] = node_curr->time_in[i];
 316                         node_real->time_in_stale[i] =
 317                                                 node_curr->time_in_stale[i];
 318                 }
 319                 if (seq_nr_after(node_curr->seq_out[i], node_real->seq_out[i]))
 320                         node_real->seq_out[i] = node_curr->seq_out[i];
 321         }
 322         node_real->addr_B_port = port_rcv->type;
 323
 324         spin_lock_bh(&hsr->list_lock);
 325         list_del_rcu(&node_curr->mac_list);
 326         spin_unlock_bh(&hsr->list_lock);
 327         kfree_rcu(node_curr, rcu_head);
 328
 329 done:
 330         /* PRP uses v0 header */
 331         if (ethhdr->h_proto == htons(ETH_P_HSR))
 332                 skb_push(skb, sizeof(struct hsrv1_ethhdr_sp));
 333         else
 334                 skb_push(skb, sizeof(struct hsrv0_ethhdr_sp));
 335 }
 336
 337 /* 'skb' is a frame meant for this host, that is to be passed to upper layers.
 338  *
 339  * If the frame was sent by a node's B interface, replace the source
 340  * address with that node's "official" address (macaddress_A) so that upper
 341  * layers recognize where it came from.
 342  */
 343 void hsr_addr_subst_source(struct hsr_node *node, struct sk_buff *skb)
 344 {
 345         if (!skb_mac_header_was_set(skb)) {
 346                 WARN_ONCE(1, "%s: Mac header not set\n", __func__);
 347                 return;
 348         }
 349
 350         memcpy(&eth_hdr(skb)->h_source, node->macaddress_A, ETH_ALEN);
 351 }
 352
 353 /* 'skb' is a frame meant for another host.
 354  * 'port' is the outgoing interface
 355  *
 356  * Substitute the target (dest) MAC address if necessary, so the it matches the
 357  * recipient interface MAC address, regardless of whether that is the
 358  * recipient's A or B interface.
 359  * This is needed to keep the packets flowing through switches that learn on
 360  * which "side" the different interfaces are.
 361  */
 362 void hsr_addr_subst_dest(struct hsr_node *node_src, struct sk_buff *skb,
 363                          struct hsr_port *port)
 364 {
 365         struct hsr_node *node_dst;
 366
 367         if (!skb_mac_header_was_set(skb)) {
 368                 WARN_ONCE(1, "%s: Mac header not set\n", __func__);
 369                 return;
 370         }
 371
 372         if (!is_unicast_ether_addr(eth_hdr(skb)->h_dest))
 373                 return;
 374
 375         node_dst = find_node_by_addr_A(&port->hsr->node_db,
 376                                        eth_hdr(skb)->h_dest);
 377         if (!node_dst) {
 378                 if (net_ratelimit())
 379                         netdev_err(skb->dev, "%s: Unknown node\n", __func__);
 380                 return;
 381         }
 382         if (port->type != node_dst->addr_B_port)
 383                 return;
 384
 385         if (is_valid_ether_addr(node_dst->macaddress_B))
 386                 ether_addr_copy(eth_hdr(skb)->h_dest, node_dst->macaddress_B);
 387 }
 388
 389 void hsr_register_frame_in(struct hsr_node *node, struct hsr_port *port,
 390                            u16 sequence_nr)
 391 {
 392         /* Don't register incoming frames without a valid sequence number. This
 393          * ensures entries of restarted nodes gets pruned so that they can
 394          * re-register and resume communications.
 395          */
 396         if (seq_nr_before(sequence_nr, node->seq_out[port->type]))
 397                 return;
 398
 399         node->time_in[port->type] = jiffies;
 400         node->time_in_stale[port->type] = false;
 401 }
 402
 403 /* 'skb' is a HSR Ethernet frame (with a HSR tag inserted), with a valid
 404  * ethhdr->h_source address and skb->mac_header set.
 405  *
 406  * Return:
 407  *       1 if frame can be shown to have been sent recently on this interface,
 408  *       0 otherwise, or
 409  *       negative error code on error
 410  */
 411 int hsr_register_frame_out(struct hsr_port *port, struct hsr_node *node,
 412                            u16 sequence_nr)
 413 {
 414         if (seq_nr_before_or_eq(sequence_nr, node->seq_out[port->type]))
 415                 return 1;
 416
 417         node->seq_out[port->type] = sequence_nr;
 418         return 0;
 419 }
 420
 421 static struct hsr_port *get_late_port(struct hsr_priv *hsr,
 422                                       struct hsr_node *node)
 423 {
 424         if (node->time_in_stale[HSR_PT_SLAVE_A])
 425                 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
 426         if (node->time_in_stale[HSR_PT_SLAVE_B])
 427                 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
 428
 429         if (time_after(node->time_in[HSR_PT_SLAVE_B],
 430                        node->time_in[HSR_PT_SLAVE_A] +
 431                                         msecs_to_jiffies(MAX_SLAVE_DIFF)))
 432                 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
 433         if (time_after(node->time_in[HSR_PT_SLAVE_A],
 434                        node->time_in[HSR_PT_SLAVE_B] +
 435                                         msecs_to_jiffies(MAX_SLAVE_DIFF)))
 436                 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
 437
 438         return NULL;
 439 }
 440
 441 /* Remove stale sequence_nr records. Called by timer every
 442  * HSR_LIFE_CHECK_INTERVAL (two seconds or so).
 443  */
 444 void hsr_prune_nodes(struct timer_list *t)
 445 {
 446         struct hsr_priv *hsr = from_timer(hsr, t, prune_timer);
 447         struct hsr_node *node;
 448         struct hsr_node *tmp;
 449         struct hsr_port *port;
 450         unsigned long timestamp;
 451         unsigned long time_a, time_b;
 452
 453         spin_lock_bh(&hsr->list_lock);
 454         list_for_each_entry_safe(node, tmp, &hsr->node_db, mac_list) {
 455                 /* Don't prune own node. Neither time_in[HSR_PT_SLAVE_A]
 456                  * nor time_in[HSR_PT_SLAVE_B], will ever be updated for
 457                  * the master port. Thus the master node will be repeatedly
 458                  * pruned leading to packet loss.
 459                  */
 460                 if (hsr_addr_is_self(hsr, node->macaddress_A))
 461                         continue;
 462
 463                 /* Shorthand */
 464                 time_a = node->time_in[HSR_PT_SLAVE_A];
 465                 time_b = node->time_in[HSR_PT_SLAVE_B];
 466
 467                 /* Check for timestamps old enough to risk wrap-around */
 468                 if (time_after(jiffies, time_a + MAX_JIFFY_OFFSET / 2))
 469                         node->time_in_stale[HSR_PT_SLAVE_A] = true;
 470                 if (time_after(jiffies, time_b + MAX_JIFFY_OFFSET / 2))
 471                         node->time_in_stale[HSR_PT_SLAVE_B] = true;
 472
 473                 /* Get age of newest frame from node.
 474                  * At least one time_in is OK here; nodes get pruned long
 475                  * before both time_ins can get stale
 476                  */
 477                 timestamp = time_a;
 478                 if (node->time_in_stale[HSR_PT_SLAVE_A] ||
 479                     (!node->time_in_stale[HSR_PT_SLAVE_B] &&
 480                     time_after(time_b, time_a)))
 481                         timestamp = time_b;
 482
 483                 /* Warn of ring error only as long as we get frames at all */
 484                 if (time_is_after_jiffies(timestamp +
 485                                 msecs_to_jiffies(1.5 * MAX_SLAVE_DIFF))) {
 486                         rcu_read_lock();
 487                         port = get_late_port(hsr, node);
 488                         if (port)
 489                                 hsr_nl_ringerror(hsr, node->macaddress_A, port);
 490                         rcu_read_unlock();
 491                 }
 492
 493                 /* Prune old entries */
 494                 if (time_is_before_jiffies(timestamp +
 495                                 msecs_to_jiffies(HSR_NODE_FORGET_TIME))) {
 496                         hsr_nl_nodedown(hsr, node->macaddress_A);
 497                         list_del_rcu(&node->mac_list);
 498                         /* Note that we need to free this entry later: */
 499                         kfree_rcu(node, rcu_head);
 500                 }
 501         }
 502         spin_unlock_bh(&hsr->list_lock);
 503
 504         /* Restart timer */
 505         mod_timer(&hsr->prune_timer,
 506                   jiffies + msecs_to_jiffies(PRUNE_PERIOD));
 507 }
 508
 509 void *hsr_get_next_node(struct hsr_priv *hsr, void *_pos,
 510                         unsigned char addr[ETH_ALEN])
 511 {
 512         struct hsr_node *node;
 513
 514         if (!_pos) {
 515                 node = list_first_or_null_rcu(&hsr->node_db,
 516                                               struct hsr_node, mac_list);
 517                 if (node)
 518                         ether_addr_copy(addr, node->macaddress_A);
 519                 return node;
 520         }
 521
 522         node = _pos;
 523         list_for_each_entry_continue_rcu(node, &hsr->node_db, mac_list) {
 524                 ether_addr_copy(addr, node->macaddress_A);
 525                 return node;
 526         }
 527
 528         return NULL;
 529 }
 530
 531 int hsr_get_node_data(struct hsr_priv *hsr,
 532                       const unsigned char *addr,
 533                       unsigned char addr_b[ETH_ALEN],
 534                       unsigned int *addr_b_ifindex,
 535                       int *if1_age,
 536                       u16 *if1_seq,
 537                       int *if2_age,
 538                       u16 *if2_seq)
 539 {
 540         struct hsr_node *node;
 541         struct hsr_port *port;
 542         unsigned long tdiff;
 543
 544         node = find_node_by_addr_A(&hsr->node_db, addr);
 545         if (!node)
 546                 return -ENOENT;
 547
 548         ether_addr_copy(addr_b, node->macaddress_B);
 549
 550         tdiff = jiffies - node->time_in[HSR_PT_SLAVE_A];
 551         if (node->time_in_stale[HSR_PT_SLAVE_A])
 552                 *if1_age = INT_MAX;
 553 #if HZ <= MSEC_PER_SEC
 554         else if (tdiff > msecs_to_jiffies(INT_MAX))
 555                 *if1_age = INT_MAX;
 556 #endif
 557         else
 558                 *if1_age = jiffies_to_msecs(tdiff);
 559
 560         tdiff = jiffies - node->time_in[HSR_PT_SLAVE_B];
 561         if (node->time_in_stale[HSR_PT_SLAVE_B])
 562                 *if2_age = INT_MAX;
 563 #if HZ <= MSEC_PER_SEC
 564         else if (tdiff > msecs_to_jiffies(INT_MAX))
 565                 *if2_age = INT_MAX;
 566 #endif
 567         else
 568                 *if2_age = jiffies_to_msecs(tdiff);
 569
 570         /* Present sequence numbers as if they were incoming on interface */
 571         *if1_seq = node->seq_out[HSR_PT_SLAVE_B];
 572         *if2_seq = node->seq_out[HSR_PT_SLAVE_A];
 573
 574         if (node->addr_B_port != HSR_PT_NONE) {
 575                 port = hsr_port_get_hsr(hsr, node->addr_B_port);
 576                 *addr_b_ifindex = port->dev->ifindex;
 577         } else {
 578                 *addr_b_ifindex = -1;
 579         }
 580
 581         return 0;
 582 }