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 26struct 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 */ 45static 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 60bool 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 */ 81static 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 */ 98int 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} 126 127 128/* Allocate an hsr_node and add it to node_db. 'addr' is the node's AddressA; 129 * seq_out is used to initialize filtering of outgoing duplicate frames 130 * originating from the newly added node. 131 */ 132struct hsr_node *hsr_add_node(struct list_head *node_db, unsigned char addr[], 133 u16 seq_out) 134{ 135 struct hsr_node *node; 136 unsigned long now; 137 int i; 138 139 node = kzalloc(sizeof(*node), GFP_ATOMIC); 140 if (!node) 141 return NULL; 142 143 ether_addr_copy(node->MacAddressA, addr); 144 145 /* We are only interested in time diffs here, so use current jiffies 146 * as initialization. (0 could trigger an spurious ring error warning). 147 */ 148 now = jiffies; 149 for (i = 0; i < HSR_PT_PORTS; i++) 150 node->time_in[i] = now; 151 for (i = 0; i < HSR_PT_PORTS; i++) 152 node->seq_out[i] = seq_out; 153 154 list_add_tail_rcu(&node->mac_list, node_db); 155 156 return node; 157} 158 159/* Get the hsr_node from which 'skb' was sent. 160 */ 161struct hsr_node *hsr_get_node(struct list_head *node_db, struct sk_buff *skb, 162 bool is_sup) 163{ 164 struct hsr_node *node; 165 struct ethhdr *ethhdr; 166 u16 seq_out; 167 168 if (!skb_mac_header_was_set(skb)) 169 return NULL; 170 171 ethhdr = (struct ethhdr *) skb_mac_header(skb); 172 173 list_for_each_entry_rcu(node, node_db, mac_list) { 174 if (ether_addr_equal(node->MacAddressA, ethhdr->h_source)) 175 return node; 176 if (ether_addr_equal(node->MacAddressB, ethhdr->h_source)) 177 return node; 178 } 179 180 if (!is_sup) 181 return NULL; /* Only supervision frame may create node entry */ 182 183 if (ethhdr->h_proto == htons(ETH_P_PRP)) { 184 /* Use the existing sequence_nr from the tag as starting point 185 * for filtering duplicate frames. 186 */ 187 seq_out = hsr_get_skb_sequence_nr(skb) - 1; 188 } else { 189 WARN_ONCE(1, "%s: Non-HSR frame\n", __func__); 190 seq_out = 0; 191 } 192 193 return hsr_add_node(node_db, ethhdr->h_source, seq_out); 194} 195 196/* Use the Supervision frame's info about an eventual MacAddressB for merging 197 * nodes that has previously had their MacAddressB registered as a separate 198 * node. 199 */ 200void hsr_handle_sup_frame(struct sk_buff *skb, struct hsr_node *node_curr, 201 struct hsr_port *port_rcv) 202{ 203 struct hsr_node *node_real; 204 struct hsr_sup_payload *hsr_sp; 205 struct list_head *node_db; 206 int i; 207 208 skb_pull(skb, sizeof(struct hsr_ethhdr_sp)); 209 hsr_sp = (struct hsr_sup_payload *) skb->data; 210 211 if (ether_addr_equal(eth_hdr(skb)->h_source, hsr_sp->MacAddressA)) 212 /* Not sent from MacAddressB of a PICS_SUBS capable node */ 213 goto done; 214 215 /* Merge node_curr (registered on MacAddressB) into node_real */ 216 node_db = &port_rcv->hsr->node_db; 217 node_real = find_node_by_AddrA(node_db, hsr_sp->MacAddressA); 218 if (!node_real) 219 /* No frame received from AddrA of this node yet */ 220 node_real = hsr_add_node(node_db, hsr_sp->MacAddressA, 221 HSR_SEQNR_START - 1); 222 if (!node_real) 223 goto done; /* No mem */ 224 if (node_real == node_curr) 225 /* Node has already been merged */ 226 goto done; 227 228 ether_addr_copy(node_real->MacAddressB, eth_hdr(skb)->h_source); 229 for (i = 0; i < HSR_PT_PORTS; i++) { 230 if (!node_curr->time_in_stale[i] && 231 time_after(node_curr->time_in[i], node_real->time_in[i])) { 232 node_real->time_in[i] = node_curr->time_in[i]; 233 node_real->time_in_stale[i] = node_curr->time_in_stale[i]; 234 } 235 if (seq_nr_after(node_curr->seq_out[i], node_real->seq_out[i])) 236 node_real->seq_out[i] = node_curr->seq_out[i]; 237 } 238 node_real->AddrB_port = port_rcv->type; 239 240 list_del_rcu(&node_curr->mac_list); 241 kfree_rcu(node_curr, rcu_head); 242 243done: 244 skb_push(skb, sizeof(struct hsr_ethhdr_sp)); 245} 246 247 248/* 'skb' is a frame meant for this host, that is to be passed to upper layers. 249 * 250 * If the frame was sent by a node's B interface, replace the source 251 * address with that node's "official" address (MacAddressA) so that upper 252 * layers recognize where it came from. 253 */ 254void hsr_addr_subst_source(struct hsr_node *node, struct sk_buff *skb) 255{ 256 if (!skb_mac_header_was_set(skb)) { 257 WARN_ONCE(1, "%s: Mac header not set\n", __func__); 258 return; 259 } 260 261 memcpy(ð_hdr(skb)->h_source, node->MacAddressA, ETH_ALEN); 262} 263 264/* 'skb' is a frame meant for another host. 265 * 'port' is the outgoing interface 266 * 267 * Substitute the target (dest) MAC address if necessary, so the it matches the 268 * recipient interface MAC address, regardless of whether that is the 269 * recipient's A or B interface. 270 * This is needed to keep the packets flowing through switches that learn on 271 * which "side" the different interfaces are. 272 */ 273void hsr_addr_subst_dest(struct hsr_node *node_src, struct sk_buff *skb, 274 struct hsr_port *port) 275{ 276 struct hsr_node *node_dst; 277 278 if (!skb_mac_header_was_set(skb)) { 279 WARN_ONCE(1, "%s: Mac header not set\n", __func__); 280 return; 281 } 282 283 if (!is_unicast_ether_addr(eth_hdr(skb)->h_dest)) 284 return; 285 286 node_dst = find_node_by_AddrA(&port->hsr->node_db, eth_hdr(skb)->h_dest); 287 if (!node_dst) { 288 WARN_ONCE(1, "%s: Unknown node\n", __func__); 289 return; 290 } 291 if (port->type != node_dst->AddrB_port) 292 return; 293 294 ether_addr_copy(eth_hdr(skb)->h_dest, node_dst->MacAddressB); 295} 296 297 298void hsr_register_frame_in(struct hsr_node *node, struct hsr_port *port, 299 u16 sequence_nr) 300{ 301 /* Don't register incoming frames without a valid sequence number. This 302 * ensures entries of restarted nodes gets pruned so that they can 303 * re-register and resume communications. 304 */ 305 if (seq_nr_before(sequence_nr, node->seq_out[port->type])) 306 return; 307 308 node->time_in[port->type] = jiffies; 309 node->time_in_stale[port->type] = false; 310} 311 312/* 'skb' is a HSR Ethernet frame (with a HSR tag inserted), with a valid 313 * ethhdr->h_source address and skb->mac_header set. 314 * 315 * Return: 316 * 1 if frame can be shown to have been sent recently on this interface, 317 * 0 otherwise, or 318 * negative error code on error 319 */ 320int hsr_register_frame_out(struct hsr_port *port, struct hsr_node *node, 321 u16 sequence_nr) 322{ 323 if (seq_nr_before_or_eq(sequence_nr, node->seq_out[port->type])) 324 return 1; 325 326 node->seq_out[port->type] = sequence_nr; 327 return 0; 328} 329 330 331static struct hsr_port *get_late_port(struct hsr_priv *hsr, 332 struct hsr_node *node) 333{ 334 if (node->time_in_stale[HSR_PT_SLAVE_A]) 335 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A); 336 if (node->time_in_stale[HSR_PT_SLAVE_B]) 337 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B); 338 339 if (time_after(node->time_in[HSR_PT_SLAVE_B], 340 node->time_in[HSR_PT_SLAVE_A] + 341 msecs_to_jiffies(MAX_SLAVE_DIFF))) 342 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A); 343 if (time_after(node->time_in[HSR_PT_SLAVE_A], 344 node->time_in[HSR_PT_SLAVE_B] + 345 msecs_to_jiffies(MAX_SLAVE_DIFF))) 346 return hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B); 347 348 return NULL; 349} 350 351 352/* Remove stale sequence_nr records. Called by timer every 353 * HSR_LIFE_CHECK_INTERVAL (two seconds or so). 354 */ 355void hsr_prune_nodes(unsigned long data) 356{ 357 struct hsr_priv *hsr; 358 struct hsr_node *node; 359 struct hsr_port *port; 360 unsigned long timestamp; 361 unsigned long time_a, time_b; 362 363 hsr = (struct hsr_priv *) data; 364 365 rcu_read_lock(); 366 list_for_each_entry_rcu(node, &hsr->node_db, mac_list) { 367 /* Shorthand */ 368 time_a = node->time_in[HSR_PT_SLAVE_A]; 369 time_b = node->time_in[HSR_PT_SLAVE_B]; 370 371 /* Check for timestamps old enough to risk wrap-around */ 372 if (time_after(jiffies, time_a + MAX_JIFFY_OFFSET/2)) 373 node->time_in_stale[HSR_PT_SLAVE_A] = true; 374 if (time_after(jiffies, time_b + MAX_JIFFY_OFFSET/2)) 375 node->time_in_stale[HSR_PT_SLAVE_B] = true; 376 377 /* Get age of newest frame from node. 378 * At least one time_in is OK here; nodes get pruned long 379 * before both time_ins can get stale 380 */ 381 timestamp = time_a; 382 if (node->time_in_stale[HSR_PT_SLAVE_A] || 383 (!node->time_in_stale[HSR_PT_SLAVE_B] && 384 time_after(time_b, time_a))) 385 timestamp = time_b; 386 387 /* Warn of ring error only as long as we get frames at all */ 388 if (time_is_after_jiffies(timestamp + 389 msecs_to_jiffies(1.5*MAX_SLAVE_DIFF))) { 390 rcu_read_lock(); 391 port = get_late_port(hsr, node); 392 if (port != NULL) 393 hsr_nl_ringerror(hsr, node->MacAddressA, port); 394 rcu_read_unlock(); 395 } 396 397 /* Prune old entries */ 398 if (time_is_before_jiffies(timestamp + 399 msecs_to_jiffies(HSR_NODE_FORGET_TIME))) { 400 hsr_nl_nodedown(hsr, node->MacAddressA); 401 list_del_rcu(&node->mac_list); 402 /* Note that we need to free this entry later: */ 403 kfree_rcu(node, rcu_head); 404 } 405 } 406 rcu_read_unlock(); 407} 408 409 410void *hsr_get_next_node(struct hsr_priv *hsr, void *_pos, 411 unsigned char addr[ETH_ALEN]) 412{ 413 struct hsr_node *node; 414 415 if (!_pos) { 416 node = list_first_or_null_rcu(&hsr->node_db, 417 struct hsr_node, mac_list); 418 if (node) 419 ether_addr_copy(addr, node->MacAddressA); 420 return node; 421 } 422 423 node = _pos; 424 list_for_each_entry_continue_rcu(node, &hsr->node_db, mac_list) { 425 ether_addr_copy(addr, node->MacAddressA); 426 return node; 427 } 428 429 return NULL; 430} 431 432 433int hsr_get_node_data(struct hsr_priv *hsr, 434 const unsigned char *addr, 435 unsigned char addr_b[ETH_ALEN], 436 unsigned int *addr_b_ifindex, 437 int *if1_age, 438 u16 *if1_seq, 439 int *if2_age, 440 u16 *if2_seq) 441{ 442 struct hsr_node *node; 443 struct hsr_port *port; 444 unsigned long tdiff; 445 446 447 rcu_read_lock(); 448 node = find_node_by_AddrA(&hsr->node_db, addr); 449 if (!node) { 450 rcu_read_unlock(); 451 return -ENOENT; /* No such entry */ 452 } 453 454 ether_addr_copy(addr_b, node->MacAddressB); 455 456 tdiff = jiffies - node->time_in[HSR_PT_SLAVE_A]; 457 if (node->time_in_stale[HSR_PT_SLAVE_A]) 458 *if1_age = INT_MAX; 459#if HZ <= MSEC_PER_SEC 460 else if (tdiff > msecs_to_jiffies(INT_MAX)) 461 *if1_age = INT_MAX; 462#endif 463 else 464 *if1_age = jiffies_to_msecs(tdiff); 465 466 tdiff = jiffies - node->time_in[HSR_PT_SLAVE_B]; 467 if (node->time_in_stale[HSR_PT_SLAVE_B]) 468 *if2_age = INT_MAX; 469#if HZ <= MSEC_PER_SEC 470 else if (tdiff > msecs_to_jiffies(INT_MAX)) 471 *if2_age = INT_MAX; 472#endif 473 else 474 *if2_age = jiffies_to_msecs(tdiff); 475 476 /* Present sequence numbers as if they were incoming on interface */ 477 *if1_seq = node->seq_out[HSR_PT_SLAVE_B]; 478 *if2_seq = node->seq_out[HSR_PT_SLAVE_A]; 479 480 if (node->AddrB_port != HSR_PT_NONE) { 481 port = hsr_port_get_hsr(hsr, node->AddrB_port); 482 *addr_b_ifindex = port->dev->ifindex; 483 } else { 484 *addr_b_ifindex = -1; 485 } 486 487 rcu_read_unlock(); 488 489 return 0; 490} 491