net/hsr/hsr_forward.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  * Frame router for HSR and PRP.
   8  */
   9
  10 #include "hsr_forward.h"
  11 #include <linux/types.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/etherdevice.h>
  14 #include <linux/if_vlan.h>
  15 #include "hsr_main.h"
  16 #include "hsr_framereg.h"
  17
  18 struct hsr_node;
  19
  20 /* The uses I can see for these HSR supervision frames are:
  21  * 1) Use the frames that are sent after node initialization ("HSR_TLV.Type =
  22  *    22") to reset any sequence_nr counters belonging to that node. Useful if
  23  *    the other node's counter has been reset for some reason.
  24  *    --
  25  *    Or not - resetting the counter and bridging the frame would create a
  26  *    loop, unfortunately.
  27  *
  28  * 2) Use the LifeCheck frames to detect ring breaks. I.e. if no LifeCheck
  29  *    frame is received from a particular node, we know something is wrong.
  30  *    We just register these (as with normal frames) and throw them away.
  31  *
  32  * 3) Allow different MAC addresses for the two slave interfaces, using the
  33  *    MacAddressA field.
  34  */
  35 static bool is_supervision_frame(struct hsr_priv *hsr, struct sk_buff *skb)
  36 {
  37         struct ethhdr *eth_hdr;
  38         struct hsr_sup_tag *hsr_sup_tag;
  39         struct hsrv1_ethhdr_sp *hsr_V1_hdr;
  40
  41         WARN_ON_ONCE(!skb_mac_header_was_set(skb));
  42         eth_hdr = (struct ethhdr *)skb_mac_header(skb);
  43
  44         /* Correct addr? */
  45         if (!ether_addr_equal(eth_hdr->h_dest,
  46                               hsr->sup_multicast_addr))
  47                 return false;
  48
  49         /* Correct ether type?. */
  50         if (!(eth_hdr->h_proto == htons(ETH_P_PRP) ||
  51               eth_hdr->h_proto == htons(ETH_P_HSR)))
  52                 return false;
  53
  54         /* Get the supervision header from correct location. */
  55         if (eth_hdr->h_proto == htons(ETH_P_HSR)) { /* Okay HSRv1. */
  56                 hsr_V1_hdr = (struct hsrv1_ethhdr_sp *)skb_mac_header(skb);
  57                 if (hsr_V1_hdr->hsr.encap_proto != htons(ETH_P_PRP))
  58                         return false;
  59
  60                 hsr_sup_tag = &hsr_V1_hdr->hsr_sup;
  61         } else {
  62                 hsr_sup_tag =
  63                      &((struct hsrv0_ethhdr_sp *)skb_mac_header(skb))->hsr_sup;
  64         }
  65
  66         if (hsr_sup_tag->HSR_TLV_type != HSR_TLV_ANNOUNCE &&
  67             hsr_sup_tag->HSR_TLV_type != HSR_TLV_LIFE_CHECK &&
  68             hsr_sup_tag->HSR_TLV_type != PRP_TLV_LIFE_CHECK_DD &&
  69             hsr_sup_tag->HSR_TLV_type != PRP_TLV_LIFE_CHECK_DA)
  70                 return false;
  71         if (hsr_sup_tag->HSR_TLV_length != 12 &&
  72             hsr_sup_tag->HSR_TLV_length != sizeof(struct hsr_sup_payload))
  73                 return false;
  74
  75         return true;
  76 }
  77
  78 static struct sk_buff *create_stripped_skb_hsr(struct sk_buff *skb_in,
  79                                                struct hsr_frame_info *frame)
  80 {
  81         struct sk_buff *skb;
  82         int copylen;
  83         unsigned char *dst, *src;
  84
  85         skb_pull(skb_in, HSR_HLEN);
  86         skb = __pskb_copy(skb_in, skb_headroom(skb_in) - HSR_HLEN, GFP_ATOMIC);
  87         skb_push(skb_in, HSR_HLEN);
  88         if (!skb)
  89                 return NULL;
  90
  91         skb_reset_mac_header(skb);
  92
  93         if (skb->ip_summed == CHECKSUM_PARTIAL)
  94                 skb->csum_start -= HSR_HLEN;
  95
  96         copylen = 2 * ETH_ALEN;
  97         if (frame->is_vlan)
  98                 copylen += VLAN_HLEN;
  99         src = skb_mac_header(skb_in);
 100         dst = skb_mac_header(skb);
 101         memcpy(dst, src, copylen);
 102
 103         skb->protocol = eth_hdr(skb)->h_proto;
 104         return skb;
 105 }
 106
 107 struct sk_buff *hsr_get_untagged_frame(struct hsr_frame_info *frame,
 108                                        struct hsr_port *port)
 109 {
 110         if (!frame->skb_std) {
 111                 if (frame->skb_hsr) {
 112                         frame->skb_std =
 113                                 create_stripped_skb_hsr(frame->skb_hsr, frame);
 114                 } else {
 115                         /* Unexpected */
 116                         WARN_ONCE(1, "%s:%d: Unexpected frame received (port_src %s)\n",
 117                                   __FILE__, __LINE__, port->dev->name);
 118                         return NULL;
 119                 }
 120         }
 121
 122         return skb_clone(frame->skb_std, GFP_ATOMIC);
 123 }
 124
 125 struct sk_buff *prp_get_untagged_frame(struct hsr_frame_info *frame,
 126                                        struct hsr_port *port)
 127 {
 128         if (!frame->skb_std) {
 129                 if (frame->skb_prp) {
 130                         /* trim the skb by len - HSR_HLEN to exclude RCT */
 131                         skb_trim(frame->skb_prp,
 132                                  frame->skb_prp->len - HSR_HLEN);
 133                         frame->skb_std =
 134                                 __pskb_copy(frame->skb_prp,
 135                                             skb_headroom(frame->skb_prp),
 136                                             GFP_ATOMIC);
 137                 } else {
 138                         /* Unexpected */
 139                         WARN_ONCE(1, "%s:%d: Unexpected frame received (port_src %s)\n",
 140                                   __FILE__, __LINE__, port->dev->name);
 141                         return NULL;
 142                 }
 143         }
 144
 145         return skb_clone(frame->skb_std, GFP_ATOMIC);
 146 }
 147
 148 static void prp_set_lan_id(struct prp_rct *trailer,
 149                            struct hsr_port *port)
 150 {
 151         int lane_id;
 152
 153         if (port->type == HSR_PT_SLAVE_A)
 154                 lane_id = 0;
 155         else
 156                 lane_id = 1;
 157
 158         /* Add net_id in the upper 3 bits of lane_id */
 159         lane_id |= port->hsr->net_id;
 160         set_prp_lan_id(trailer, lane_id);
 161 }
 162
 163 /* Tailroom for PRP rct should have been created before calling this */
 164 static struct sk_buff *prp_fill_rct(struct sk_buff *skb,
 165                                     struct hsr_frame_info *frame,
 166                                     struct hsr_port *port)
 167 {
 168         struct prp_rct *trailer;
 169         int min_size = ETH_ZLEN;
 170         int lsdu_size;
 171
 172         if (!skb)
 173                 return skb;
 174
 175         if (frame->is_vlan)
 176                 min_size = VLAN_ETH_ZLEN;
 177
 178         if (skb_put_padto(skb, min_size))
 179                 return NULL;
 180
 181         trailer = (struct prp_rct *)skb_put(skb, HSR_HLEN);
 182         lsdu_size = skb->len - 14;
 183         if (frame->is_vlan)
 184                 lsdu_size -= 4;
 185         prp_set_lan_id(trailer, port);
 186         set_prp_LSDU_size(trailer, lsdu_size);
 187         trailer->sequence_nr = htons(frame->sequence_nr);
 188         trailer->PRP_suffix = htons(ETH_P_PRP);
 189
 190         return skb;
 191 }
 192
 193 static void hsr_set_path_id(struct hsr_ethhdr *hsr_ethhdr,
 194                             struct hsr_port *port)
 195 {
 196         int path_id;
 197
 198         if (port->type == HSR_PT_SLAVE_A)
 199                 path_id = 0;
 200         else
 201                 path_id = 1;
 202
 203         set_hsr_tag_path(&hsr_ethhdr->hsr_tag, path_id);
 204 }
 205
 206 static struct sk_buff *hsr_fill_tag(struct sk_buff *skb,
 207                                     struct hsr_frame_info *frame,
 208                                     struct hsr_port *port, u8 proto_version)
 209 {
 210         struct hsr_ethhdr *hsr_ethhdr;
 211         int lsdu_size;
 212
 213         /* pad to minimum packet size which is 60 + 6 (HSR tag) */
 214         if (skb_put_padto(skb, ETH_ZLEN + HSR_HLEN))
 215                 return NULL;
 216
 217         lsdu_size = skb->len - 14;
 218         if (frame->is_vlan)
 219                 lsdu_size -= 4;
 220
 221         hsr_ethhdr = (struct hsr_ethhdr *)skb_mac_header(skb);
 222
 223         hsr_set_path_id(hsr_ethhdr, port);
 224         set_hsr_tag_LSDU_size(&hsr_ethhdr->hsr_tag, lsdu_size);
 225         hsr_ethhdr->hsr_tag.sequence_nr = htons(frame->sequence_nr);
 226         hsr_ethhdr->hsr_tag.encap_proto = hsr_ethhdr->ethhdr.h_proto;
 227         hsr_ethhdr->ethhdr.h_proto = htons(proto_version ?
 228                         ETH_P_HSR : ETH_P_PRP);
 229
 230         return skb;
 231 }
 232
 233 /* If the original frame was an HSR tagged frame, just clone it to be sent
 234  * unchanged. Otherwise, create a private frame especially tagged for 'port'.
 235  */
 236 struct sk_buff *hsr_create_tagged_frame(struct hsr_frame_info *frame,
 237                                         struct hsr_port *port)
 238 {
 239         unsigned char *dst, *src;
 240         struct sk_buff *skb;
 241         int movelen;
 242
 243         if (frame->skb_hsr) {
 244                 struct hsr_ethhdr *hsr_ethhdr =
 245                         (struct hsr_ethhdr *)skb_mac_header(frame->skb_hsr);
 246
 247                 /* set the lane id properly */
 248                 hsr_set_path_id(hsr_ethhdr, port);
 249                 return skb_clone(frame->skb_hsr, GFP_ATOMIC);
 250         }
 251
 252         /* Create the new skb with enough headroom to fit the HSR tag */
 253         skb = __pskb_copy(frame->skb_std,
 254                           skb_headroom(frame->skb_std) + HSR_HLEN, GFP_ATOMIC);
 255         if (!skb)
 256                 return NULL;
 257         skb_reset_mac_header(skb);
 258
 259         if (skb->ip_summed == CHECKSUM_PARTIAL)
 260                 skb->csum_start += HSR_HLEN;
 261
 262         movelen = ETH_HLEN;
 263         if (frame->is_vlan)
 264                 movelen += VLAN_HLEN;
 265
 266         src = skb_mac_header(skb);
 267         dst = skb_push(skb, HSR_HLEN);
 268         memmove(dst, src, movelen);
 269         skb_reset_mac_header(skb);
 270
 271         /* skb_put_padto free skb on error and hsr_fill_tag returns NULL in
 272          * that case
 273          */
 274         return hsr_fill_tag(skb, frame, port, port->hsr->prot_version);
 275 }
 276
 277 struct sk_buff *prp_create_tagged_frame(struct hsr_frame_info *frame,
 278                                         struct hsr_port *port)
 279 {
 280         struct sk_buff *skb;
 281
 282         if (frame->skb_prp) {
 283                 struct prp_rct *trailer = skb_get_PRP_rct(frame->skb_prp);
 284
 285                 if (trailer) {
 286                         prp_set_lan_id(trailer, port);
 287                 } else {
 288                         WARN_ONCE(!trailer, "errored PRP skb");
 289                         return NULL;
 290                 }
 291                 return skb_clone(frame->skb_prp, GFP_ATOMIC);
 292         }
 293
 294         skb = skb_copy_expand(frame->skb_std, 0,
 295                               skb_tailroom(frame->skb_std) + HSR_HLEN,
 296                               GFP_ATOMIC);
 297         prp_fill_rct(skb, frame, port);
 298
 299         return skb;
 300 }
 301
 302 static void hsr_deliver_master(struct sk_buff *skb, struct net_device *dev,
 303                                struct hsr_node *node_src)
 304 {
 305         bool was_multicast_frame;
 306         int res;
 307
 308         was_multicast_frame = (skb->pkt_type == PACKET_MULTICAST);
 309         hsr_addr_subst_source(node_src, skb);
 310         skb_pull(skb, ETH_HLEN);
 311         res = netif_rx(skb);
 312         if (res == NET_RX_DROP) {
 313                 dev->stats.rx_dropped++;
 314         } else {
 315                 dev->stats.rx_packets++;
 316                 dev->stats.rx_bytes += skb->len;
 317                 if (was_multicast_frame)
 318                         dev->stats.multicast++;
 319         }
 320 }
 321
 322 static int hsr_xmit(struct sk_buff *skb, struct hsr_port *port,
 323                     struct hsr_frame_info *frame)
 324 {
 325         if (frame->port_rcv->type == HSR_PT_MASTER) {
 326                 hsr_addr_subst_dest(frame->node_src, skb, port);
 327
 328                 /* Address substitution (IEC62439-3 pp 26, 50): replace mac
 329                  * address of outgoing frame with that of the outgoing slave's.
 330                  */
 331                 ether_addr_copy(eth_hdr(skb)->h_source, port->dev->dev_addr);
 332         }
 333         return dev_queue_xmit(skb);
 334 }
 335
 336 bool prp_drop_frame(struct hsr_frame_info *frame, struct hsr_port *port)
 337 {
 338         return ((frame->port_rcv->type == HSR_PT_SLAVE_A &&
 339                  port->type ==  HSR_PT_SLAVE_B) ||
 340                 (frame->port_rcv->type == HSR_PT_SLAVE_B &&
 341                  port->type ==  HSR_PT_SLAVE_A));
 342 }
 343
 344 /* Forward the frame through all devices except:
 345  * - Back through the receiving device
 346  * - If it's a HSR frame: through a device where it has passed before
 347  * - if it's a PRP frame: through another PRP slave device (no bridge)
 348  * - To the local HSR master only if the frame is directly addressed to it, or
 349  *   a non-supervision multicast or broadcast frame.
 350  *
 351  * HSR slave devices should insert a HSR tag into the frame, or forward the
 352  * frame unchanged if it's already tagged. Interlink devices should strip HSR
 353  * tags if they're of the non-HSR type (but only after duplicate discard). The
 354  * master device always strips HSR tags.
 355  */
 356 static void hsr_forward_do(struct hsr_frame_info *frame)
 357 {
 358         struct hsr_port *port;
 359         struct sk_buff *skb;
 360
 361         hsr_for_each_port(frame->port_rcv->hsr, port) {
 362                 struct hsr_priv *hsr = port->hsr;
 363                 /* Don't send frame back the way it came */
 364                 if (port == frame->port_rcv)
 365                         continue;
 366
 367                 /* Don't deliver locally unless we should */
 368                 if (port->type == HSR_PT_MASTER && !frame->is_local_dest)
 369                         continue;
 370
 371                 /* Deliver frames directly addressed to us to master only */
 372                 if (port->type != HSR_PT_MASTER && frame->is_local_exclusive)
 373                         continue;
 374
 375                 /* Don't send frame over port where it has been sent before.
 376                  * Also fro SAN, this shouldn't be done.
 377                  */
 378                 if (!frame->is_from_san &&
 379                     hsr_register_frame_out(port, frame->node_src,
 380                                            frame->sequence_nr))
 381                         continue;
 382
 383                 if (frame->is_supervision && port->type == HSR_PT_MASTER) {
 384                         hsr_handle_sup_frame(frame);
 385                         continue;
 386                 }
 387
 388                 /* Check if frame is to be dropped. Eg. for PRP no forward
 389                  * between ports.
 390                  */
 391                 if (hsr->proto_ops->drop_frame &&
 392                     hsr->proto_ops->drop_frame(frame, port))
 393                         continue;
 394
 395                 if (port->type != HSR_PT_MASTER)
 396                         skb = hsr->proto_ops->create_tagged_frame(frame, port);
 397                 else
 398                         skb = hsr->proto_ops->get_untagged_frame(frame, port);
 399
 400                 if (!skb) {
 401                         frame->port_rcv->dev->stats.rx_dropped++;
 402                         continue;
 403                 }
 404
 405                 skb->dev = port->dev;
 406                 if (port->type == HSR_PT_MASTER)
 407                         hsr_deliver_master(skb, port->dev, frame->node_src);
 408                 else
 409                         hsr_xmit(skb, port, frame);
 410         }
 411 }
 412
 413 static void check_local_dest(struct hsr_priv *hsr, struct sk_buff *skb,
 414                              struct hsr_frame_info *frame)
 415 {
 416         if (hsr_addr_is_self(hsr, eth_hdr(skb)->h_dest)) {
 417                 frame->is_local_exclusive = true;
 418                 skb->pkt_type = PACKET_HOST;
 419         } else {
 420                 frame->is_local_exclusive = false;
 421         }
 422
 423         if (skb->pkt_type == PACKET_HOST ||
 424             skb->pkt_type == PACKET_MULTICAST ||
 425             skb->pkt_type == PACKET_BROADCAST) {
 426                 frame->is_local_dest = true;
 427         } else {
 428                 frame->is_local_dest = false;
 429         }
 430 }
 431
 432 static void handle_std_frame(struct sk_buff *skb,
 433                              struct hsr_frame_info *frame)
 434 {
 435         struct hsr_port *port = frame->port_rcv;
 436         struct hsr_priv *hsr = port->hsr;
 437         unsigned long irqflags;
 438
 439         frame->skb_hsr = NULL;
 440         frame->skb_prp = NULL;
 441         frame->skb_std = skb;
 442
 443         if (port->type != HSR_PT_MASTER) {
 444                 frame->is_from_san = true;
 445         } else {
 446                 /* Sequence nr for the master node */
 447                 spin_lock_irqsave(&hsr->seqnr_lock, irqflags);
 448                 frame->sequence_nr = hsr->sequence_nr;
 449                 hsr->sequence_nr++;
 450                 spin_unlock_irqrestore(&hsr->seqnr_lock, irqflags);
 451         }
 452 }
 453
 454 void hsr_fill_frame_info(__be16 proto, struct sk_buff *skb,
 455                          struct hsr_frame_info *frame)
 456 {
 457         if (proto == htons(ETH_P_PRP) ||
 458             proto == htons(ETH_P_HSR)) {
 459                 /* HSR tagged frame :- Data or Supervision */
 460                 frame->skb_std = NULL;
 461                 frame->skb_prp = NULL;
 462                 frame->skb_hsr = skb;
 463                 frame->sequence_nr = hsr_get_skb_sequence_nr(skb);
 464                 return;
 465         }
 466
 467         /* Standard frame or PRP from master port */
 468         handle_std_frame(skb, frame);
 469 }
 470
 471 void prp_fill_frame_info(__be16 proto, struct sk_buff *skb,
 472                          struct hsr_frame_info *frame)
 473 {
 474         /* Supervision frame */
 475         struct prp_rct *rct = skb_get_PRP_rct(skb);
 476
 477         if (rct &&
 478             prp_check_lsdu_size(skb, rct, frame->is_supervision)) {
 479                 frame->skb_hsr = NULL;
 480                 frame->skb_std = NULL;
 481                 frame->skb_prp = skb;
 482                 frame->sequence_nr = prp_get_skb_sequence_nr(rct);
 483                 return;
 484         }
 485         handle_std_frame(skb, frame);
 486 }
 487
 488 static int fill_frame_info(struct hsr_frame_info *frame,
 489                            struct sk_buff *skb, struct hsr_port *port)
 490 {
 491         struct hsr_priv *hsr = port->hsr;
 492         struct hsr_vlan_ethhdr *vlan_hdr;
 493         struct ethhdr *ethhdr;
 494         __be16 proto;
 495
 496         memset(frame, 0, sizeof(*frame));
 497         frame->is_supervision = is_supervision_frame(port->hsr, skb);
 498         frame->node_src = hsr_get_node(port, &hsr->node_db, skb,
 499                                        frame->is_supervision,
 500                                        port->type);
 501         if (!frame->node_src)
 502                 return -1; /* Unknown node and !is_supervision, or no mem */
 503
 504         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 505         frame->is_vlan = false;
 506         proto = ethhdr->h_proto;
 507
 508         if (proto == htons(ETH_P_8021Q))
 509                 frame->is_vlan = true;
 510
 511         if (frame->is_vlan) {
 512                 vlan_hdr = (struct hsr_vlan_ethhdr *)ethhdr;
 513                 proto = vlan_hdr->vlanhdr.h_vlan_encapsulated_proto;
 514                 /* FIXME: */
 515                 netdev_warn_once(skb->dev, "VLAN not yet supported");
 516         }
 517
 518         frame->is_from_san = false;
 519         frame->port_rcv = port;
 520         hsr->proto_ops->fill_frame_info(proto, skb, frame);
 521         check_local_dest(port->hsr, skb, frame);
 522
 523         return 0;
 524 }
 525
 526 /* Must be called holding rcu read lock (because of the port parameter) */
 527 void hsr_forward_skb(struct sk_buff *skb, struct hsr_port *port)
 528 {
 529         struct hsr_frame_info frame;
 530
 531         if (skb_mac_header(skb) != skb->data) {
 532                 WARN_ONCE(1, "%s:%d: Malformed frame (port_src %s)\n",
 533                           __FILE__, __LINE__, port->dev->name);
 534                 goto out_drop;
 535         }
 536
 537         if (fill_frame_info(&frame, skb, port) < 0)
 538                 goto out_drop;
 539
 540         hsr_register_frame_in(frame.node_src, port, frame.sequence_nr);
 541         hsr_forward_do(&frame);
 542         /* Gets called for ingress frames as well as egress from master port.
 543          * So check and increment stats for master port only here.
 544          */
 545         if (port->type == HSR_PT_MASTER) {
 546                 port->dev->stats.tx_packets++;
 547                 port->dev->stats.tx_bytes += skb->len;
 548         }
 549
 550         kfree_skb(frame.skb_hsr);
 551         kfree_skb(frame.skb_prp);
 552         kfree_skb(frame.skb_std);
 553         return;
 554
 555 out_drop:
 556         port->dev->stats.tx_dropped++;
 557         kfree_skb(skb);
 558 }