root/net/hsr/hsr_framereg.c

DEFINITIONS

1. seq_nr_after
2. hsr_addr_is_self
3. find_node_by_addr_A
4. hsr_create_self_node
5. hsr_del_self_node
6. hsr_del_nodes
7. hsr_add_node
8. hsr_get_node
9. hsr_handle_sup_frame
10. hsr_addr_subst_source
11. hsr_addr_subst_dest
12. hsr_register_frame_in
13. hsr_register_frame_out
14. get_late_port
15. hsr_prune_nodes
16. hsr_get_next_node
17. hsr_get_node_data

   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_after_or_eq(a, b)        (!seq_nr_before((a), (b)))
  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 /* Allocate an hsr_node and add it to node_db. 'addr' is the node's address_A;
 131  * seq_out is used to initialize filtering of outgoing duplicate frames
 132  * originating from the newly added node.
 133  */
 134 static struct hsr_node *hsr_add_node(struct hsr_priv *hsr,
 135                                      struct list_head *node_db,
 136                                      unsigned char addr[],
 137                                      u16 seq_out)
 138 {
 139         struct hsr_node *new_node, *node;
 140         unsigned long now;
 141         int i;
 142 
 143         new_node = kzalloc(sizeof(*new_node), GFP_ATOMIC);
 144         if (!new_node)
 145                 return NULL;
 146 
 147         ether_addr_copy(new_node->macaddress_A, addr);
 148 
 149         /* We are only interested in time diffs here, so use current jiffies
 150          * as initialization. (0 could trigger an spurious ring error warning).
 151          */
 152         now = jiffies;
 153         for (i = 0; i < HSR_PT_PORTS; i++)
 154                 new_node->time_in[i] = now;
 155         for (i = 0; i < HSR_PT_PORTS; i++)
 156                 new_node->seq_out[i] = seq_out;
 157 
 158         spin_lock_bh(&hsr->list_lock);
 159         list_for_each_entry_rcu(node, node_db, mac_list) {
 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                 WARN_ONCE(1, "%s: Unknown node\n", __func__);
 322                 return;
 323         }
 324         if (port->type != node_dst->addr_B_port)
 325                 return;
 326 
 327         ether_addr_copy(eth_hdr(skb)->h_dest, node_dst->macaddress_B);
 328 }
 329 
 330 void hsr_register_frame_in(struct hsr_node *node, struct hsr_port *port,
 331                            u16 sequence_nr)
 332 {
 333         /* Don't register incoming frames without a valid sequence number. This
 334          * ensures entries of restarted nodes gets pruned so that they can
 335          * re-register and resume communications.
 336          */
 337         if (seq_nr_before(sequence_nr, node->seq_out[port->type]))
 338                 return;
 339 
 340         node->time_in[port->type] = jiffies;
 341         node->time_in_stale[port->type] = false;
 342 }
 343 
 344 /* 'skb' is a HSR Ethernet frame (with a HSR tag inserted), with a valid
 345  * ethhdr->h_source address and skb->mac_header set.
 346  *
 347  * Return:
 348  *       1 if frame can be shown to have been sent recently on this interface,
 349  *       0 otherwise, or
 350  *       negative error code on error
 351  */
 352 int hsr_register_frame_out(struct hsr_port *port, struct hsr_node *node,
 353                            u16 sequence_nr)
 354 {
 355         if (seq_nr_before_or_eq(sequence_nr, node->seq_out[port->type]))
 356                 return 1;
 357 
 358         node->seq_out[port->type] = sequence_nr;
 359         return 0;
 360 }
 361 
 362 static struct hsr_port *get_late_port(struct hsr_priv *hsr,
 363                                       struct hsr_node *node)
 364 {
 365         if (node->time_in_stale[HSR_PT_SLAVE_A])
 366                 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
 367         if (node->time_in_stale[HSR_PT_SLAVE_B])
 368                 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
 369 
 370         if (time_after(node->time_in[HSR_PT_SLAVE_B],
 371                        node->time_in[HSR_PT_SLAVE_A] +
 372                                         msecs_to_jiffies(MAX_SLAVE_DIFF)))
 373                 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
 374         if (time_after(node->time_in[HSR_PT_SLAVE_A],
 375                        node->time_in[HSR_PT_SLAVE_B] +
 376                                         msecs_to_jiffies(MAX_SLAVE_DIFF)))
 377                 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
 378 
 379         return NULL;
 380 }
 381 
 382 /* Remove stale sequence_nr records. Called by timer every
 383  * HSR_LIFE_CHECK_INTERVAL (two seconds or so).
 384  */
 385 void hsr_prune_nodes(struct timer_list *t)
 386 {
 387         struct hsr_priv *hsr = from_timer(hsr, t, prune_timer);
 388         struct hsr_node *node;
 389         struct hsr_node *tmp;
 390         struct hsr_port *port;
 391         unsigned long timestamp;
 392         unsigned long time_a, time_b;
 393 
 394         spin_lock_bh(&hsr->list_lock);
 395         list_for_each_entry_safe(node, tmp, &hsr->node_db, mac_list) {
 396                 /* Don't prune own node. Neither time_in[HSR_PT_SLAVE_A]
 397                  * nor time_in[HSR_PT_SLAVE_B], will ever be updated for
 398                  * the master port. Thus the master node will be repeatedly
 399                  * pruned leading to packet loss.
 400                  */
 401                 if (hsr_addr_is_self(hsr, node->macaddress_A))
 402                         continue;
 403 
 404                 /* Shorthand */
 405                 time_a = node->time_in[HSR_PT_SLAVE_A];
 406                 time_b = node->time_in[HSR_PT_SLAVE_B];
 407 
 408                 /* Check for timestamps old enough to risk wrap-around */
 409                 if (time_after(jiffies, time_a + MAX_JIFFY_OFFSET / 2))
 410                         node->time_in_stale[HSR_PT_SLAVE_A] = true;
 411                 if (time_after(jiffies, time_b + MAX_JIFFY_OFFSET / 2))
 412                         node->time_in_stale[HSR_PT_SLAVE_B] = true;
 413 
 414                 /* Get age of newest frame from node.
 415                  * At least one time_in is OK here; nodes get pruned long
 416                  * before both time_ins can get stale
 417                  */
 418                 timestamp = time_a;
 419                 if (node->time_in_stale[HSR_PT_SLAVE_A] ||
 420                     (!node->time_in_stale[HSR_PT_SLAVE_B] &&
 421                     time_after(time_b, time_a)))
 422                         timestamp = time_b;
 423 
 424                 /* Warn of ring error only as long as we get frames at all */
 425                 if (time_is_after_jiffies(timestamp +
 426                                 msecs_to_jiffies(1.5 * MAX_SLAVE_DIFF))) {
 427                         rcu_read_lock();
 428                         port = get_late_port(hsr, node);
 429                         if (port)
 430                                 hsr_nl_ringerror(hsr, node->macaddress_A, port);
 431                         rcu_read_unlock();
 432                 }
 433 
 434                 /* Prune old entries */
 435                 if (time_is_before_jiffies(timestamp +
 436                                 msecs_to_jiffies(HSR_NODE_FORGET_TIME))) {
 437                         hsr_nl_nodedown(hsr, node->macaddress_A);
 438                         list_del_rcu(&node->mac_list);
 439                         /* Note that we need to free this entry later: */
 440                         kfree_rcu(node, rcu_head);
 441                 }
 442         }
 443         spin_unlock_bh(&hsr->list_lock);
 444 
 445         /* Restart timer */
 446         mod_timer(&hsr->prune_timer,
 447                   jiffies + msecs_to_jiffies(PRUNE_PERIOD));
 448 }
 449 
 450 void *hsr_get_next_node(struct hsr_priv *hsr, void *_pos,
 451                         unsigned char addr[ETH_ALEN])
 452 {
 453         struct hsr_node *node;
 454 
 455         if (!_pos) {
 456                 node = list_first_or_null_rcu(&hsr->node_db,
 457                                               struct hsr_node, mac_list);
 458                 if (node)
 459                         ether_addr_copy(addr, node->macaddress_A);
 460                 return node;
 461         }
 462 
 463         node = _pos;
 464         list_for_each_entry_continue_rcu(node, &hsr->node_db, mac_list) {
 465                 ether_addr_copy(addr, node->macaddress_A);
 466                 return node;
 467         }
 468 
 469         return NULL;
 470 }
 471 
 472 int hsr_get_node_data(struct hsr_priv *hsr,
 473                       const unsigned char *addr,
 474                       unsigned char addr_b[ETH_ALEN],
 475                       unsigned int *addr_b_ifindex,
 476                       int *if1_age,
 477                       u16 *if1_seq,
 478                       int *if2_age,
 479                       u16 *if2_seq)
 480 {
 481         struct hsr_node *node;
 482         struct hsr_port *port;
 483         unsigned long tdiff;
 484 
 485         node = find_node_by_addr_A(&hsr->node_db, addr);
 486         if (!node)
 487                 return -ENOENT;
 488 
 489         ether_addr_copy(addr_b, node->macaddress_B);
 490 
 491         tdiff = jiffies - node->time_in[HSR_PT_SLAVE_A];
 492         if (node->time_in_stale[HSR_PT_SLAVE_A])
 493                 *if1_age = INT_MAX;
 494 #if HZ <= MSEC_PER_SEC
 495         else if (tdiff > msecs_to_jiffies(INT_MAX))
 496                 *if1_age = INT_MAX;
 497 #endif
 498         else
 499                 *if1_age = jiffies_to_msecs(tdiff);
 500 
 501         tdiff = jiffies - node->time_in[HSR_PT_SLAVE_B];
 502         if (node->time_in_stale[HSR_PT_SLAVE_B])
 503                 *if2_age = INT_MAX;
 504 #if HZ <= MSEC_PER_SEC
 505         else if (tdiff > msecs_to_jiffies(INT_MAX))
 506                 *if2_age = INT_MAX;
 507 #endif
 508         else
 509                 *if2_age = jiffies_to_msecs(tdiff);
 510 
 511         /* Present sequence numbers as if they were incoming on interface */
 512         *if1_seq = node->seq_out[HSR_PT_SLAVE_B];
 513         *if2_seq = node->seq_out[HSR_PT_SLAVE_A];
 514 
 515         if (node->addr_B_port != HSR_PT_NONE) {
 516                 port = hsr_port_get_hsr(hsr, node->addr_B_port);
 517                 *addr_b_ifindex = port->dev->ifindex;
 518         } else {
 519                 *addr_b_ifindex = -1;
 520         }
 521 
 522         return 0;
 523 }