net/hsr/hsr_framereg.c

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