net/hsr/hsr_forward.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
  12 #include "hsr_forward.h"
  13 #include <linux/types.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/etherdevice.h>
  16 #include <linux/if_vlan.h>
  17 #include "hsr_main.h"
  18 #include "hsr_framereg.h"
  19
  20
  21 struct hsr_node;
  22
  23 struct hsr_frame_info {
  24         struct sk_buff *skb_std;
  25         struct sk_buff *skb_hsr;
  26         struct hsr_port *port_rcv;
  27         struct hsr_node *node_src;
  28         u16 sequence_nr;
  29         bool is_supervision;
  30         bool is_vlan;
  31         bool is_local_dest;
  32         bool is_local_exclusive;
  33 };
  34
  35
  36 /* The uses I can see for these HSR supervision frames are:
  37  * 1) Use the frames that are sent after node initialization ("HSR_TLV.Type =
  38  *    22") to reset any sequence_nr counters belonging to that node. Useful if
  39  *    the other node's counter has been reset for some reason.
  40  *    --
  41  *    Or not - resetting the counter and bridging the frame would create a
  42  *    loop, unfortunately.
  43  *
  44  * 2) Use the LifeCheck frames to detect ring breaks. I.e. if no LifeCheck
  45  *    frame is received from a particular node, we know something is wrong.
  46  *    We just register these (as with normal frames) and throw them away.
  47  *
  48  * 3) Allow different MAC addresses for the two slave interfaces, using the
  49  *    MacAddressA field.
  50  */
  51 static bool is_supervision_frame(struct hsr_priv *hsr, struct sk_buff *skb)
  52 {
  53         struct ethhdr *ethHdr;
  54         struct hsr_sup_tag *hsrSupTag;
  55         struct hsrv1_ethhdr_sp *hsrV1Hdr;
  56
  57         WARN_ON_ONCE(!skb_mac_header_was_set(skb));
  58         ethHdr = (struct ethhdr *) skb_mac_header(skb);
  59
  60         /* Correct addr? */
  61         if (!ether_addr_equal(ethHdr->h_dest,
  62                               hsr->sup_multicast_addr))
  63                 return false;
  64
  65         /* Correct ether type?. */
  66         if (!(ethHdr->h_proto == htons(ETH_P_PRP)
  67                         || ethHdr->h_proto == htons(ETH_P_HSR)))
  68                 return false;
  69
  70         /* Get the supervision header from correct location. */
  71         if (ethHdr->h_proto == htons(ETH_P_HSR)) { /* Okay HSRv1. */
  72                 hsrV1Hdr = (struct hsrv1_ethhdr_sp *) skb_mac_header(skb);
  73                 if (hsrV1Hdr->hsr.encap_proto != htons(ETH_P_PRP))
  74                         return false;
  75
  76                 hsrSupTag = &hsrV1Hdr->hsr_sup;
  77         } else {
  78                 hsrSupTag = &((struct hsrv0_ethhdr_sp *) skb_mac_header(skb))->hsr_sup;
  79         }
  80
  81         if ((hsrSupTag->HSR_TLV_Type != HSR_TLV_ANNOUNCE) &&
  82             (hsrSupTag->HSR_TLV_Type != HSR_TLV_LIFE_CHECK))
  83                 return false;
  84         if ((hsrSupTag->HSR_TLV_Length != 12) &&
  85                         (hsrSupTag->HSR_TLV_Length !=
  86                                         sizeof(struct hsr_sup_payload)))
  87                 return false;
  88
  89         return true;
  90 }
  91
  92
  93 static struct sk_buff *create_stripped_skb(struct sk_buff *skb_in,
  94                                            struct hsr_frame_info *frame)
  95 {
  96         struct sk_buff *skb;
  97         int copylen;
  98         unsigned char *dst, *src;
  99
 100         skb_pull(skb_in, HSR_HLEN);
 101         skb = __pskb_copy(skb_in, skb_headroom(skb_in) - HSR_HLEN, GFP_ATOMIC);
 102         skb_push(skb_in, HSR_HLEN);
 103         if (skb == NULL)
 104                 return NULL;
 105
 106         skb_reset_mac_header(skb);
 107
 108         if (skb->ip_summed == CHECKSUM_PARTIAL)
 109                 skb->csum_start -= HSR_HLEN;
 110
 111         copylen = 2*ETH_ALEN;
 112         if (frame->is_vlan)
 113                 copylen += VLAN_HLEN;
 114         src = skb_mac_header(skb_in);
 115         dst = skb_mac_header(skb);
 116         memcpy(dst, src, copylen);
 117
 118         skb->protocol = eth_hdr(skb)->h_proto;
 119         return skb;
 120 }
 121
 122 static struct sk_buff *frame_get_stripped_skb(struct hsr_frame_info *frame,
 123                                               struct hsr_port *port)
 124 {
 125         if (!frame->skb_std)
 126                 frame->skb_std = create_stripped_skb(frame->skb_hsr, frame);
 127         return skb_clone(frame->skb_std, GFP_ATOMIC);
 128 }
 129
 130
 131 static void hsr_fill_tag(struct sk_buff *skb, struct hsr_frame_info *frame,
 132                          struct hsr_port *port, u8 protoVersion)
 133 {
 134         struct hsr_ethhdr *hsr_ethhdr;
 135         int lane_id;
 136         int lsdu_size;
 137
 138         if (port->type == HSR_PT_SLAVE_A)
 139                 lane_id = 0;
 140         else
 141                 lane_id = 1;
 142
 143         lsdu_size = skb->len - 14;
 144         if (frame->is_vlan)
 145                 lsdu_size -= 4;
 146
 147         hsr_ethhdr = (struct hsr_ethhdr *) skb_mac_header(skb);
 148
 149         set_hsr_tag_path(&hsr_ethhdr->hsr_tag, lane_id);
 150         set_hsr_tag_LSDU_size(&hsr_ethhdr->hsr_tag, lsdu_size);
 151         hsr_ethhdr->hsr_tag.sequence_nr = htons(frame->sequence_nr);
 152         hsr_ethhdr->hsr_tag.encap_proto = hsr_ethhdr->ethhdr.h_proto;
 153         hsr_ethhdr->ethhdr.h_proto = htons(protoVersion ?
 154                         ETH_P_HSR : ETH_P_PRP);
 155 }
 156
 157 static struct sk_buff *create_tagged_skb(struct sk_buff *skb_o,
 158                                          struct hsr_frame_info *frame,
 159                                          struct hsr_port *port)
 160 {
 161         int movelen;
 162         unsigned char *dst, *src;
 163         struct sk_buff *skb;
 164
 165         /* Create the new skb with enough headroom to fit the HSR tag */
 166         skb = __pskb_copy(skb_o, skb_headroom(skb_o) + HSR_HLEN, GFP_ATOMIC);
 167         if (skb == NULL)
 168                 return NULL;
 169         skb_reset_mac_header(skb);
 170
 171         if (skb->ip_summed == CHECKSUM_PARTIAL)
 172                 skb->csum_start += HSR_HLEN;
 173
 174         movelen = ETH_HLEN;
 175         if (frame->is_vlan)
 176                 movelen += VLAN_HLEN;
 177
 178         src = skb_mac_header(skb);
 179         dst = skb_push(skb, HSR_HLEN);
 180         memmove(dst, src, movelen);
 181         skb_reset_mac_header(skb);
 182
 183         hsr_fill_tag(skb, frame, port, port->hsr->protVersion);
 184
 185         return skb;
 186 }
 187
 188 /* If the original frame was an HSR tagged frame, just clone it to be sent
 189  * unchanged. Otherwise, create a private frame especially tagged for 'port'.
 190  */
 191 static struct sk_buff *frame_get_tagged_skb(struct hsr_frame_info *frame,
 192                                             struct hsr_port *port)
 193 {
 194         if (frame->skb_hsr)
 195                 return skb_clone(frame->skb_hsr, GFP_ATOMIC);
 196
 197         if ((port->type != HSR_PT_SLAVE_A) && (port->type != HSR_PT_SLAVE_B)) {
 198                 WARN_ONCE(1, "HSR: Bug: trying to create a tagged frame for a non-ring port");
 199                 return NULL;
 200         }
 201
 202         return create_tagged_skb(frame->skb_std, frame, port);
 203 }
 204
 205
 206 static void hsr_deliver_master(struct sk_buff *skb, struct net_device *dev,
 207                                struct hsr_node *node_src)
 208 {
 209         bool was_multicast_frame;
 210         int res;
 211
 212         was_multicast_frame = (skb->pkt_type == PACKET_MULTICAST);
 213         hsr_addr_subst_source(node_src, skb);
 214         skb_pull(skb, ETH_HLEN);
 215         res = netif_rx(skb);
 216         if (res == NET_RX_DROP) {
 217                 dev->stats.rx_dropped++;
 218         } else {
 219                 dev->stats.rx_packets++;
 220                 dev->stats.rx_bytes += skb->len;
 221                 if (was_multicast_frame)
 222                         dev->stats.multicast++;
 223         }
 224 }
 225
 226 static int hsr_xmit(struct sk_buff *skb, struct hsr_port *port,
 227                     struct hsr_frame_info *frame)
 228 {
 229         if (frame->port_rcv->type == HSR_PT_MASTER) {
 230                 hsr_addr_subst_dest(frame->node_src, skb, port);
 231
 232                 /* Address substitution (IEC62439-3 pp 26, 50): replace mac
 233                  * address of outgoing frame with that of the outgoing slave's.
 234                  */
 235                 ether_addr_copy(eth_hdr(skb)->h_source, port->dev->dev_addr);
 236         }
 237         return dev_queue_xmit(skb);
 238 }
 239
 240
 241 /* Forward the frame through all devices except:
 242  * - Back through the receiving device
 243  * - If it's a HSR frame: through a device where it has passed before
 244  * - To the local HSR master only if the frame is directly addressed to it, or
 245  *   a non-supervision multicast or broadcast frame.
 246  *
 247  * HSR slave devices should insert a HSR tag into the frame, or forward the
 248  * frame unchanged if it's already tagged. Interlink devices should strip HSR
 249  * tags if they're of the non-HSR type (but only after duplicate discard). The
 250  * master device always strips HSR tags.
 251  */
 252 static void hsr_forward_do(struct hsr_frame_info *frame)
 253 {
 254         struct hsr_port *port;
 255         struct sk_buff *skb;
 256
 257         hsr_for_each_port(frame->port_rcv->hsr, port) {
 258                 /* Don't send frame back the way it came */
 259                 if (port == frame->port_rcv)
 260                         continue;
 261
 262                 /* Don't deliver locally unless we should */
 263                 if ((port->type == HSR_PT_MASTER) && !frame->is_local_dest)
 264                         continue;
 265
 266                 /* Deliver frames directly addressed to us to master only */
 267                 if ((port->type != HSR_PT_MASTER) && frame->is_local_exclusive)
 268                         continue;
 269
 270                 /* Don't send frame over port where it has been sent before */
 271                 if (hsr_register_frame_out(port, frame->node_src,
 272                                            frame->sequence_nr))
 273                         continue;
 274
 275                 if (frame->is_supervision && (port->type == HSR_PT_MASTER)) {
 276                         hsr_handle_sup_frame(frame->skb_hsr,
 277                                              frame->node_src,
 278                                              frame->port_rcv);
 279                         continue;
 280                 }
 281
 282                 if (port->type != HSR_PT_MASTER)
 283                         skb = frame_get_tagged_skb(frame, port);
 284                 else
 285                         skb = frame_get_stripped_skb(frame, port);
 286                 if (skb == NULL) {
 287                         /* FIXME: Record the dropped frame? */
 288                         continue;
 289                 }
 290
 291                 skb->dev = port->dev;
 292                 if (port->type == HSR_PT_MASTER)
 293                         hsr_deliver_master(skb, port->dev, frame->node_src);
 294                 else
 295                         hsr_xmit(skb, port, frame);
 296         }
 297 }
 298
 299
 300 static void check_local_dest(struct hsr_priv *hsr, struct sk_buff *skb,
 301                              struct hsr_frame_info *frame)
 302 {
 303         struct net_device *master_dev;
 304
 305         master_dev = hsr_port_get_hsr(hsr, HSR_PT_MASTER)->dev;
 306
 307         if (hsr_addr_is_self(hsr, eth_hdr(skb)->h_dest)) {
 308                 frame->is_local_exclusive = true;
 309                 skb->pkt_type = PACKET_HOST;
 310         } else {
 311                 frame->is_local_exclusive = false;
 312         }
 313
 314         if ((skb->pkt_type == PACKET_HOST) ||
 315             (skb->pkt_type == PACKET_MULTICAST) ||
 316             (skb->pkt_type == PACKET_BROADCAST)) {
 317                 frame->is_local_dest = true;
 318         } else {
 319                 frame->is_local_dest = false;
 320         }
 321 }
 322
 323
 324 static int hsr_fill_frame_info(struct hsr_frame_info *frame,
 325                                struct sk_buff *skb, struct hsr_port *port)
 326 {
 327         struct ethhdr *ethhdr;
 328         unsigned long irqflags;
 329
 330         frame->is_supervision = is_supervision_frame(port->hsr, skb);
 331         frame->node_src = hsr_get_node(&port->hsr->node_db, skb,
 332                                        frame->is_supervision);
 333         if (frame->node_src == NULL)
 334                 return -1; /* Unknown node and !is_supervision, or no mem */
 335
 336         ethhdr = (struct ethhdr *) skb_mac_header(skb);
 337         frame->is_vlan = false;
 338         if (ethhdr->h_proto == htons(ETH_P_8021Q)) {
 339                 frame->is_vlan = true;
 340                 /* FIXME: */
 341                 WARN_ONCE(1, "HSR: VLAN not yet supported");
 342         }
 343         if (ethhdr->h_proto == htons(ETH_P_PRP)
 344                         || ethhdr->h_proto == htons(ETH_P_HSR)) {
 345                 frame->skb_std = NULL;
 346                 frame->skb_hsr = skb;
 347                 frame->sequence_nr = hsr_get_skb_sequence_nr(skb);
 348         } else {
 349                 frame->skb_std = skb;
 350                 frame->skb_hsr = NULL;
 351                 /* Sequence nr for the master node */
 352                 spin_lock_irqsave(&port->hsr->seqnr_lock, irqflags);
 353                 frame->sequence_nr = port->hsr->sequence_nr;
 354                 port->hsr->sequence_nr++;
 355                 spin_unlock_irqrestore(&port->hsr->seqnr_lock, irqflags);
 356         }
 357
 358         frame->port_rcv = port;
 359         check_local_dest(port->hsr, skb, frame);
 360
 361         return 0;
 362 }
 363
 364 /* Must be called holding rcu read lock (because of the port parameter) */
 365 void hsr_forward_skb(struct sk_buff *skb, struct hsr_port *port)
 366 {
 367         struct hsr_frame_info frame;
 368
 369         if (skb_mac_header(skb) != skb->data) {
 370                 WARN_ONCE(1, "%s:%d: Malformed frame (port_src %s)\n",
 371                           __FILE__, __LINE__, port->dev->name);
 372                 goto out_drop;
 373         }
 374
 375         if (hsr_fill_frame_info(&frame, skb, port) < 0)
 376                 goto out_drop;
 377         hsr_register_frame_in(frame.node_src, port, frame.sequence_nr);
 378         hsr_forward_do(&frame);
 379
 380         if (frame.skb_hsr != NULL)
 381                 kfree_skb(frame.skb_hsr);
 382         if (frame.skb_std != NULL)
 383                 kfree_skb(frame.skb_std);
 384         return;
 385
 386 out_drop:
 387         port->dev->stats.tx_dropped++;
 388         kfree_skb(skb);
 389 }