LXR linux/net/hsr/hsr

   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
  21struct hsr_node;
  22
  23struct 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 */
  51static bool is_supervision_frame(struct hsr_priv *hsr, struct sk_buff *skb)
  52{
  53        struct hsr_ethhdr_sp *hdr;
  54
  55        WARN_ON_ONCE(!skb_mac_header_was_set(skb));
  56        hdr = (struct hsr_ethhdr_sp *) skb_mac_header(skb);
  57
  58        if (!ether_addr_equal(hdr->ethhdr.h_dest,
  59                              hsr->sup_multicast_addr))
  60                return false;
  61
  62        if (get_hsr_stag_path(&hdr->hsr_sup) != 0x0f)
  63                return false;
  64        if ((hdr->hsr_sup.HSR_TLV_Type != HSR_TLV_ANNOUNCE) &&
  65            (hdr->hsr_sup.HSR_TLV_Type != HSR_TLV_LIFE_CHECK))
  66                return false;
  67        if (hdr->hsr_sup.HSR_TLV_Length != 12)
  68                return false;
  69
  70        return true;
  71}
  72
  73
  74static struct sk_buff *create_stripped_skb(struct sk_buff *skb_in,
  75                                           struct hsr_frame_info *frame)
  76{
  77        struct sk_buff *skb;
  78        int copylen;
  79        unsigned char *dst, *src;
  80
  81        skb_pull(skb_in, HSR_HLEN);
  82        skb = __pskb_copy(skb_in, skb_headroom(skb_in) - HSR_HLEN, GFP_ATOMIC);
  83        skb_push(skb_in, HSR_HLEN);
  84        if (skb == NULL)
  85                return NULL;
  86
  87        skb_reset_mac_header(skb);
  88
  89        if (skb->ip_summed == CHECKSUM_PARTIAL)
  90                skb->csum_start -= HSR_HLEN;
  91
  92        copylen = 2*ETH_ALEN;
  93        if (frame->is_vlan)
  94                copylen += VLAN_HLEN;
  95        src = skb_mac_header(skb_in);
  96        dst = skb_mac_header(skb);
  97        memcpy(dst, src, copylen);
  98
  99        skb->protocol = eth_hdr(skb)->h_proto;
 100        return skb;
 101}
 102
 103static struct sk_buff *frame_get_stripped_skb(struct hsr_frame_info *frame,
 104                                              struct hsr_port *port)
 105{
 106        if (!frame->skb_std)
 107                frame->skb_std = create_stripped_skb(frame->skb_hsr, frame);
 108        return skb_clone(frame->skb_std, GFP_ATOMIC);
 109}
 110
 111
 112static void hsr_fill_tag(struct sk_buff *skb, struct hsr_frame_info *frame,
 113                         struct hsr_port *port)
 114{
 115        struct hsr_ethhdr *hsr_ethhdr;
 116        int lane_id;
 117        int lsdu_size;
 118
 119        if (port->type == HSR_PT_SLAVE_A)
 120                lane_id = 0;
 121        else
 122                lane_id = 1;
 123
 124        lsdu_size = skb->len - 14;
 125        if (frame->is_vlan)
 126                lsdu_size -= 4;
 127
 128        hsr_ethhdr = (struct hsr_ethhdr *) skb_mac_header(skb);
 129
 130        set_hsr_tag_path(&hsr_ethhdr->hsr_tag, lane_id);
 131        set_hsr_tag_LSDU_size(&hsr_ethhdr->hsr_tag, lsdu_size);
 132        hsr_ethhdr->hsr_tag.sequence_nr = htons(frame->sequence_nr);
 133        hsr_ethhdr->hsr_tag.encap_proto = hsr_ethhdr->ethhdr.h_proto;
 134        hsr_ethhdr->ethhdr.h_proto = htons(ETH_P_PRP);
 135}
 136
 137static struct sk_buff *create_tagged_skb(struct sk_buff *skb_o,
 138                                         struct hsr_frame_info *frame,
 139                                         struct hsr_port *port)
 140{
 141        int movelen;
 142        unsigned char *dst, *src;
 143        struct sk_buff *skb;
 144
 145        /* Create the new skb with enough headroom to fit the HSR tag */
 146        skb = __pskb_copy(skb_o, skb_headroom(skb_o) + HSR_HLEN, GFP_ATOMIC);
 147        if (skb == NULL)
 148                return NULL;
 149        skb_reset_mac_header(skb);
 150
 151        if (skb->ip_summed == CHECKSUM_PARTIAL)
 152                skb->csum_start += HSR_HLEN;
 153
 154        movelen = ETH_HLEN;
 155        if (frame->is_vlan)
 156                movelen += VLAN_HLEN;
 157
 158        src = skb_mac_header(skb);
 159        dst = skb_push(skb, HSR_HLEN);
 160        memmove(dst, src, movelen);
 161        skb_reset_mac_header(skb);
 162
 163        hsr_fill_tag(skb, frame, port);
 164
 165        return skb;
 166}
 167
 168/* If the original frame was an HSR tagged frame, just clone it to be sent
 169 * unchanged. Otherwise, create a private frame especially tagged for 'port'.
 170 */
 171static struct sk_buff *frame_get_tagged_skb(struct hsr_frame_info *frame,
 172                                            struct hsr_port *port)
 173{
 174        if (frame->skb_hsr)
 175                return skb_clone(frame->skb_hsr, GFP_ATOMIC);
 176
 177        if ((port->type != HSR_PT_SLAVE_A) && (port->type != HSR_PT_SLAVE_B)) {
 178                WARN_ONCE(1, "HSR: Bug: trying to create a tagged frame for a non-ring port");
 179                return NULL;
 180        }
 181
 182        return create_tagged_skb(frame->skb_std, frame, port);
 183}
 184
 185
 186static void hsr_deliver_master(struct sk_buff *skb, struct net_device *dev,
 187                               struct hsr_node *node_src)
 188{
 189        bool was_multicast_frame;
 190        int res;
 191
 192        was_multicast_frame = (skb->pkt_type == PACKET_MULTICAST);
 193        hsr_addr_subst_source(node_src, skb);
 194        skb_pull(skb, ETH_HLEN);
 195        res = netif_rx(skb);
 196        if (res == NET_RX_DROP) {
 197                dev->stats.rx_dropped++;
 198        } else {
 199                dev->stats.rx_packets++;
 200                dev->stats.rx_bytes += skb->len;
 201                if (was_multicast_frame)
 202                        dev->stats.multicast++;
 203        }
 204}
 205
 206static int hsr_xmit(struct sk_buff *skb, struct hsr_port *port,
 207                    struct hsr_frame_info *frame)
 208{
 209        if (frame->port_rcv->type == HSR_PT_MASTER) {
 210                hsr_addr_subst_dest(frame->node_src, skb, port);
 211
 212                /* Address substitution (IEC62439-3 pp 26, 50): replace mac
 213                 * address of outgoing frame with that of the outgoing slave's.
 214                 */
 215                ether_addr_copy(eth_hdr(skb)->h_source, port->dev->dev_addr);
 216        }
 217        return dev_queue_xmit(skb);
 218}
 219
 220
 221/* Forward the frame through all devices except:
 222 * - Back through the receiving device
 223 * - If it's a HSR frame: through a device where it has passed before
 224 * - To the local HSR master only if the frame is directly addressed to it, or
 225 *   a non-supervision multicast or broadcast frame.
 226 *
 227 * HSR slave devices should insert a HSR tag into the frame, or forward the
 228 * frame unchanged if it's already tagged. Interlink devices should strip HSR
 229 * tags if they're of the non-HSR type (but only after duplicate discard). The
 230 * master device always strips HSR tags.
 231 */
 232static void hsr_forward_do(struct hsr_frame_info *frame)
 233{
 234        struct hsr_port *port;
 235        struct sk_buff *skb;
 236
 237        hsr_for_each_port(frame->port_rcv->hsr, port) {
 238                /* Don't send frame back the way it came */
 239                if (port == frame->port_rcv)
 240                        continue;
 241
 242                /* Don't deliver locally unless we should */
 243                if ((port->type == HSR_PT_MASTER) && !frame->is_local_dest)
 244                        continue;
 245
 246                /* Deliver frames directly addressed to us to master only */
 247                if ((port->type != HSR_PT_MASTER) && frame->is_local_exclusive)
 248                        continue;
 249
 250                /* Don't send frame over port where it has been sent before */
 251                if (hsr_register_frame_out(port, frame->node_src,
 252                                           frame->sequence_nr))
 253                        continue;
 254
 255                if (frame->is_supervision && (port->type == HSR_PT_MASTER)) {
 256                        hsr_handle_sup_frame(frame->skb_hsr,
 257                                             frame->node_src,
 258                                             frame->port_rcv);
 259                        continue;
 260                }
 261
 262                if (port->type != HSR_PT_MASTER)
 263                        skb = frame_get_tagged_skb(frame, port);
 264                else
 265                        skb = frame_get_stripped_skb(frame, port);
 266                if (skb == NULL) {
 267                        /* FIXME: Record the dropped frame? */
 268                        continue;
 269                }
 270
 271                skb->dev = port->dev;
 272                if (port->type == HSR_PT_MASTER)
 273                        hsr_deliver_master(skb, port->dev, frame->node_src);
 274                else
 275                        hsr_xmit(skb, port, frame);
 276        }
 277}
 278
 279
 280static void check_local_dest(struct hsr_priv *hsr, struct sk_buff *skb,
 281                             struct hsr_frame_info *frame)
 282{
 283        struct net_device *master_dev;
 284
 285        master_dev = hsr_port_get_hsr(hsr, HSR_PT_MASTER)->dev;
 286
 287        if (hsr_addr_is_self(hsr, eth_hdr(skb)->h_dest)) {
 288                frame->is_local_exclusive = true;
 289                skb->pkt_type = PACKET_HOST;
 290        } else {
 291                frame->is_local_exclusive = false;
 292        }
 293
 294        if ((skb->pkt_type == PACKET_HOST) ||
 295            (skb->pkt_type == PACKET_MULTICAST) ||
 296            (skb->pkt_type == PACKET_BROADCAST)) {
 297                frame->is_local_dest = true;
 298        } else {
 299                frame->is_local_dest = false;
 300        }
 301}
 302
 303
 304static int hsr_fill_frame_info(struct hsr_frame_info *frame,
 305                               struct sk_buff *skb, struct hsr_port *port)
 306{
 307        struct ethhdr *ethhdr;
 308        unsigned long irqflags;
 309
 310        frame->is_supervision = is_supervision_frame(port->hsr, skb);
 311        frame->node_src = hsr_get_node(&port->hsr->node_db, skb,
 312                                       frame->is_supervision);
 313        if (frame->node_src == NULL)
 314                return -1; /* Unknown node and !is_supervision, or no mem */
 315
 316        ethhdr = (struct ethhdr *) skb_mac_header(skb);
 317        frame->is_vlan = false;
 318        if (ethhdr->h_proto == htons(ETH_P_8021Q)) {
 319                frame->is_vlan = true;
 320                /* FIXME: */
 321                WARN_ONCE(1, "HSR: VLAN not yet supported");
 322        }
 323        if (ethhdr->h_proto == htons(ETH_P_PRP)) {
 324                frame->skb_std = NULL;
 325                frame->skb_hsr = skb;
 326                frame->sequence_nr = hsr_get_skb_sequence_nr(skb);
 327        } else {
 328                frame->skb_std = skb;
 329                frame->skb_hsr = NULL;
 330                /* Sequence nr for the master node */
 331                spin_lock_irqsave(&port->hsr->seqnr_lock, irqflags);
 332                frame->sequence_nr = port->hsr->sequence_nr;
 333                port->hsr->sequence_nr++;
 334                spin_unlock_irqrestore(&port->hsr->seqnr_lock, irqflags);
 335        }
 336
 337        frame->port_rcv = port;
 338        check_local_dest(port->hsr, skb, frame);
 339
 340        return 0;
 341}
 342
 343/* Must be called holding rcu read lock (because of the port parameter) */
 344void hsr_forward_skb(struct sk_buff *skb, struct hsr_port *port)
 345{
 346        struct hsr_frame_info frame;
 347
 348        if (skb_mac_header(skb) != skb->data) {
 349                WARN_ONCE(1, "%s:%d: Malformed frame (port_src %s)\n",
 350                          __FILE__, __LINE__, port->dev->name);
 351                goto out_drop;
 352        }
 353
 354        if (hsr_fill_frame_info(&frame, skb, port) < 0)
 355                goto out_drop;
 356        hsr_register_frame_in(frame.node_src, port, frame.sequence_nr);
 357        hsr_forward_do(&frame);
 358
 359        if (frame.skb_hsr != NULL)
 360                kfree_skb(frame.skb_hsr);
 361        if (frame.skb_std != NULL)
 362                kfree_skb(frame.skb_std);
 363        return;
 364
 365out_drop:
 366        port->dev->stats.tx_dropped++;
 367        kfree_skb(skb);
 368}
 369