root/net/hsr/hsr_forward.c

DEFINITIONS

1. is_supervision_frame
2. create_stripped_skb
3. frame_get_stripped_skb
4. hsr_fill_tag
5. create_tagged_skb
6. frame_get_tagged_skb
7. hsr_deliver_master
8. hsr_xmit
9. hsr_forward_do
10. check_local_dest
11. hsr_fill_frame_info
12. hsr_forward_skb

   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 
   8 #include "hsr_forward.h"
   9 #include <linux/types.h>
  10 #include <linux/skbuff.h>
  11 #include <linux/etherdevice.h>
  12 #include <linux/if_vlan.h>
  13 #include "hsr_main.h"
  14 #include "hsr_framereg.h"
  15 
  16 struct hsr_node;
  17 
  18 struct hsr_frame_info {
  19         struct sk_buff *skb_std;
  20         struct sk_buff *skb_hsr;
  21         struct hsr_port *port_rcv;
  22         struct hsr_node *node_src;
  23         u16 sequence_nr;
  24         bool is_supervision;
  25         bool is_vlan;
  26         bool is_local_dest;
  27         bool is_local_exclusive;
  28 };
  29 
  30 /* The uses I can see for these HSR supervision frames are:
  31  * 1) Use the frames that are sent after node initialization ("HSR_TLV.Type =
  32  *    22") to reset any sequence_nr counters belonging to that node. Useful if
  33  *    the other node's counter has been reset for some reason.
  34  *    --
  35  *    Or not - resetting the counter and bridging the frame would create a
  36  *    loop, unfortunately.
  37  *
  38  * 2) Use the LifeCheck frames to detect ring breaks. I.e. if no LifeCheck
  39  *    frame is received from a particular node, we know something is wrong.
  40  *    We just register these (as with normal frames) and throw them away.
  41  *
  42  * 3) Allow different MAC addresses for the two slave interfaces, using the
  43  *    MacAddressA field.
  44  */
  45 static bool is_supervision_frame(struct hsr_priv *hsr, struct sk_buff *skb)
  46 {
  47         struct ethhdr *eth_hdr;
  48         struct hsr_sup_tag *hsr_sup_tag;
  49         struct hsrv1_ethhdr_sp *hsr_V1_hdr;
  50 
  51         WARN_ON_ONCE(!skb_mac_header_was_set(skb));
  52         eth_hdr = (struct ethhdr *)skb_mac_header(skb);
  53 
  54         /* Correct addr? */
  55         if (!ether_addr_equal(eth_hdr->h_dest,
  56                               hsr->sup_multicast_addr))
  57                 return false;
  58 
  59         /* Correct ether type?. */
  60         if (!(eth_hdr->h_proto == htons(ETH_P_PRP) ||
  61               eth_hdr->h_proto == htons(ETH_P_HSR)))
  62                 return false;
  63 
  64         /* Get the supervision header from correct location. */
  65         if (eth_hdr->h_proto == htons(ETH_P_HSR)) { /* Okay HSRv1. */
  66                 hsr_V1_hdr = (struct hsrv1_ethhdr_sp *)skb_mac_header(skb);
  67                 if (hsr_V1_hdr->hsr.encap_proto != htons(ETH_P_PRP))
  68                         return false;
  69 
  70                 hsr_sup_tag = &hsr_V1_hdr->hsr_sup;
  71         } else {
  72                 hsr_sup_tag =
  73                      &((struct hsrv0_ethhdr_sp *)skb_mac_header(skb))->hsr_sup;
  74         }
  75 
  76         if (hsr_sup_tag->HSR_TLV_type != HSR_TLV_ANNOUNCE &&
  77             hsr_sup_tag->HSR_TLV_type != HSR_TLV_LIFE_CHECK)
  78                 return false;
  79         if (hsr_sup_tag->HSR_TLV_length != 12 &&
  80             hsr_sup_tag->HSR_TLV_length != sizeof(struct hsr_sup_payload))
  81                 return false;
  82 
  83         return true;
  84 }
  85 
  86 static struct sk_buff *create_stripped_skb(struct sk_buff *skb_in,
  87                                            struct hsr_frame_info *frame)
  88 {
  89         struct sk_buff *skb;
  90         int copylen;
  91         unsigned char *dst, *src;
  92 
  93         skb_pull(skb_in, HSR_HLEN);
  94         skb = __pskb_copy(skb_in, skb_headroom(skb_in) - HSR_HLEN, GFP_ATOMIC);
  95         skb_push(skb_in, HSR_HLEN);
  96         if (!skb)
  97                 return NULL;
  98 
  99         skb_reset_mac_header(skb);
 100 
 101         if (skb->ip_summed == CHECKSUM_PARTIAL)
 102                 skb->csum_start -= HSR_HLEN;
 103 
 104         copylen = 2 * ETH_ALEN;
 105         if (frame->is_vlan)
 106                 copylen += VLAN_HLEN;
 107         src = skb_mac_header(skb_in);
 108         dst = skb_mac_header(skb);
 109         memcpy(dst, src, copylen);
 110 
 111         skb->protocol = eth_hdr(skb)->h_proto;
 112         return skb;
 113 }
 114 
 115 static struct sk_buff *frame_get_stripped_skb(struct hsr_frame_info *frame,
 116                                               struct hsr_port *port)
 117 {
 118         if (!frame->skb_std)
 119                 frame->skb_std = create_stripped_skb(frame->skb_hsr, frame);
 120         return skb_clone(frame->skb_std, GFP_ATOMIC);
 121 }
 122 
 123 static void hsr_fill_tag(struct sk_buff *skb, struct hsr_frame_info *frame,
 124                          struct hsr_port *port, u8 proto_version)
 125 {
 126         struct hsr_ethhdr *hsr_ethhdr;
 127         int lane_id;
 128         int lsdu_size;
 129 
 130         if (port->type == HSR_PT_SLAVE_A)
 131                 lane_id = 0;
 132         else
 133                 lane_id = 1;
 134 
 135         lsdu_size = skb->len - 14;
 136         if (frame->is_vlan)
 137                 lsdu_size -= 4;
 138 
 139         hsr_ethhdr = (struct hsr_ethhdr *)skb_mac_header(skb);
 140 
 141         set_hsr_tag_path(&hsr_ethhdr->hsr_tag, lane_id);
 142         set_hsr_tag_LSDU_size(&hsr_ethhdr->hsr_tag, lsdu_size);
 143         hsr_ethhdr->hsr_tag.sequence_nr = htons(frame->sequence_nr);
 144         hsr_ethhdr->hsr_tag.encap_proto = hsr_ethhdr->ethhdr.h_proto;
 145         hsr_ethhdr->ethhdr.h_proto = htons(proto_version ?
 146                         ETH_P_HSR : ETH_P_PRP);
 147 }
 148 
 149 static struct sk_buff *create_tagged_skb(struct sk_buff *skb_o,
 150                                          struct hsr_frame_info *frame,
 151                                          struct hsr_port *port)
 152 {
 153         int movelen;
 154         unsigned char *dst, *src;
 155         struct sk_buff *skb;
 156 
 157         /* Create the new skb with enough headroom to fit the HSR tag */
 158         skb = __pskb_copy(skb_o, skb_headroom(skb_o) + HSR_HLEN, GFP_ATOMIC);
 159         if (!skb)
 160                 return NULL;
 161         skb_reset_mac_header(skb);
 162 
 163         if (skb->ip_summed == CHECKSUM_PARTIAL)
 164                 skb->csum_start += HSR_HLEN;
 165 
 166         movelen = ETH_HLEN;
 167         if (frame->is_vlan)
 168                 movelen += VLAN_HLEN;
 169 
 170         src = skb_mac_header(skb);
 171         dst = skb_push(skb, HSR_HLEN);
 172         memmove(dst, src, movelen);
 173         skb_reset_mac_header(skb);
 174 
 175         hsr_fill_tag(skb, frame, port, port->hsr->prot_version);
 176 
 177         return skb;
 178 }
 179 
 180 /* If the original frame was an HSR tagged frame, just clone it to be sent
 181  * unchanged. Otherwise, create a private frame especially tagged for 'port'.
 182  */
 183 static struct sk_buff *frame_get_tagged_skb(struct hsr_frame_info *frame,
 184                                             struct hsr_port *port)
 185 {
 186         if (frame->skb_hsr)
 187                 return skb_clone(frame->skb_hsr, GFP_ATOMIC);
 188 
 189         if (port->type != HSR_PT_SLAVE_A && port->type != HSR_PT_SLAVE_B) {
 190                 WARN_ONCE(1, "HSR: Bug: trying to create a tagged frame for a non-ring port");
 191                 return NULL;
 192         }
 193 
 194         return create_tagged_skb(frame->skb_std, frame, port);
 195 }
 196 
 197 static void hsr_deliver_master(struct sk_buff *skb, struct net_device *dev,
 198                                struct hsr_node *node_src)
 199 {
 200         bool was_multicast_frame;
 201         int res;
 202 
 203         was_multicast_frame = (skb->pkt_type == PACKET_MULTICAST);
 204         hsr_addr_subst_source(node_src, skb);
 205         skb_pull(skb, ETH_HLEN);
 206         res = netif_rx(skb);
 207         if (res == NET_RX_DROP) {
 208                 dev->stats.rx_dropped++;
 209         } else {
 210                 dev->stats.rx_packets++;
 211                 dev->stats.rx_bytes += skb->len;
 212                 if (was_multicast_frame)
 213                         dev->stats.multicast++;
 214         }
 215 }
 216 
 217 static int hsr_xmit(struct sk_buff *skb, struct hsr_port *port,
 218                     struct hsr_frame_info *frame)
 219 {
 220         if (frame->port_rcv->type == HSR_PT_MASTER) {
 221                 hsr_addr_subst_dest(frame->node_src, skb, port);
 222 
 223                 /* Address substitution (IEC62439-3 pp 26, 50): replace mac
 224                  * address of outgoing frame with that of the outgoing slave's.
 225                  */
 226                 ether_addr_copy(eth_hdr(skb)->h_source, port->dev->dev_addr);
 227         }
 228         return dev_queue_xmit(skb);
 229 }
 230 
 231 /* Forward the frame through all devices except:
 232  * - Back through the receiving device
 233  * - If it's a HSR frame: through a device where it has passed before
 234  * - To the local HSR master only if the frame is directly addressed to it, or
 235  *   a non-supervision multicast or broadcast frame.
 236  *
 237  * HSR slave devices should insert a HSR tag into the frame, or forward the
 238  * frame unchanged if it's already tagged. Interlink devices should strip HSR
 239  * tags if they're of the non-HSR type (but only after duplicate discard). The
 240  * master device always strips HSR tags.
 241  */
 242 static void hsr_forward_do(struct hsr_frame_info *frame)
 243 {
 244         struct hsr_port *port;
 245         struct sk_buff *skb;
 246 
 247         hsr_for_each_port(frame->port_rcv->hsr, port) {
 248                 /* Don't send frame back the way it came */
 249                 if (port == frame->port_rcv)
 250                         continue;
 251 
 252                 /* Don't deliver locally unless we should */
 253                 if (port->type == HSR_PT_MASTER && !frame->is_local_dest)
 254                         continue;
 255 
 256                 /* Deliver frames directly addressed to us to master only */
 257                 if (port->type != HSR_PT_MASTER && frame->is_local_exclusive)
 258                         continue;
 259 
 260                 /* Don't send frame over port where it has been sent before */
 261                 if (hsr_register_frame_out(port, frame->node_src,
 262                                            frame->sequence_nr))
 263                         continue;
 264 
 265                 if (frame->is_supervision && port->type == HSR_PT_MASTER) {
 266                         hsr_handle_sup_frame(frame->skb_hsr,
 267                                              frame->node_src,
 268                                              frame->port_rcv);
 269                         continue;
 270                 }
 271 
 272                 if (port->type != HSR_PT_MASTER)
 273                         skb = frame_get_tagged_skb(frame, port);
 274                 else
 275                         skb = frame_get_stripped_skb(frame, port);
 276                 if (!skb) {
 277                         /* FIXME: Record the dropped frame? */
 278                         continue;
 279                 }
 280 
 281                 skb->dev = port->dev;
 282                 if (port->type == HSR_PT_MASTER)
 283                         hsr_deliver_master(skb, port->dev, frame->node_src);
 284                 else
 285                         hsr_xmit(skb, port, frame);
 286         }
 287 }
 288 
 289 static void check_local_dest(struct hsr_priv *hsr, struct sk_buff *skb,
 290                              struct hsr_frame_info *frame)
 291 {
 292         if (hsr_addr_is_self(hsr, eth_hdr(skb)->h_dest)) {
 293                 frame->is_local_exclusive = true;
 294                 skb->pkt_type = PACKET_HOST;
 295         } else {
 296                 frame->is_local_exclusive = false;
 297         }
 298 
 299         if (skb->pkt_type == PACKET_HOST ||
 300             skb->pkt_type == PACKET_MULTICAST ||
 301             skb->pkt_type == PACKET_BROADCAST) {
 302                 frame->is_local_dest = true;
 303         } else {
 304                 frame->is_local_dest = false;
 305         }
 306 }
 307 
 308 static int hsr_fill_frame_info(struct hsr_frame_info *frame,
 309                                struct sk_buff *skb, struct hsr_port *port)
 310 {
 311         struct ethhdr *ethhdr;
 312         unsigned long irqflags;
 313 
 314         frame->is_supervision = is_supervision_frame(port->hsr, skb);
 315         frame->node_src = hsr_get_node(port, skb, frame->is_supervision);
 316         if (!frame->node_src)
 317                 return -1; /* Unknown node and !is_supervision, or no mem */
 318 
 319         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 320         frame->is_vlan = false;
 321         if (ethhdr->h_proto == htons(ETH_P_8021Q)) {
 322                 frame->is_vlan = true;
 323                 /* FIXME: */
 324                 WARN_ONCE(1, "HSR: VLAN not yet supported");
 325         }
 326         if (ethhdr->h_proto == htons(ETH_P_PRP) ||
 327             ethhdr->h_proto == htons(ETH_P_HSR)) {
 328                 frame->skb_std = NULL;
 329                 frame->skb_hsr = skb;
 330                 frame->sequence_nr = hsr_get_skb_sequence_nr(skb);
 331         } else {
 332                 frame->skb_std = skb;
 333                 frame->skb_hsr = NULL;
 334                 /* Sequence nr for the master node */
 335                 spin_lock_irqsave(&port->hsr->seqnr_lock, irqflags);
 336                 frame->sequence_nr = port->hsr->sequence_nr;
 337                 port->hsr->sequence_nr++;
 338                 spin_unlock_irqrestore(&port->hsr->seqnr_lock, irqflags);
 339         }
 340 
 341         frame->port_rcv = port;
 342         check_local_dest(port->hsr, skb, frame);
 343 
 344         return 0;
 345 }
 346 
 347 /* Must be called holding rcu read lock (because of the port parameter) */
 348 void hsr_forward_skb(struct sk_buff *skb, struct hsr_port *port)
 349 {
 350         struct hsr_frame_info frame;
 351 
 352         if (skb_mac_header(skb) != skb->data) {
 353                 WARN_ONCE(1, "%s:%d: Malformed frame (port_src %s)\n",
 354                           __FILE__, __LINE__, port->dev->name);
 355                 goto out_drop;
 356         }
 357 
 358         if (hsr_fill_frame_info(&frame, skb, port) < 0)
 359                 goto out_drop;
 360         hsr_register_frame_in(frame.node_src, port, frame.sequence_nr);
 361         hsr_forward_do(&frame);
 362         /* Gets called for ingress frames as well as egress from master port.
 363          * So check and increment stats for master port only here.
 364          */
 365         if (port->type == HSR_PT_MASTER) {
 366                 port->dev->stats.tx_packets++;
 367                 port->dev->stats.tx_bytes += skb->len;
 368         }
 369 
 370         if (frame.skb_hsr)
 371                 kfree_skb(frame.skb_hsr);
 372         if (frame.skb_std)
 373                 kfree_skb(frame.skb_std);
 374         return;
 375 
 376 out_drop:
 377         port->dev->stats.tx_dropped++;
 378         kfree_skb(skb);
 379 }