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/* Copyright 2011-2014 Autronica Fire and Security AS
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
* Author(s):
* 2011-2014 Arvid Brodin,
#include "hsr_forward.h"
#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/etherdevice.h>
#include <linux/if_vlan.h>
#include "hsr_main.h"
#include "hsr_framereg.h"
struct hsr_node;
struct hsr_frame_info {
struct sk_buff *skb_std;
struct sk_buff *skb_hsr;
struct hsr_port *port_rcv;
struct hsr_node *node_src;
u16 sequence_nr;
bool is_supervision;
bool is_vlan;
bool is_local_dest;
bool is_local_exclusive;
/* The uses I can see for these HSR supervision frames are:
* 1) Use the frames that are sent after node initialization ("HSR_TLV.Type =
* 22") to reset any sequence_nr counters belonging to that node. Useful if
* the other node's counter has been reset for some reason.
* --
* Or not - resetting the counter and bridging the frame would create a
* loop, unfortunately.
* 2) Use the LifeCheck frames to detect ring breaks. I.e. if no LifeCheck
* frame is received from a particular node, we know something is wrong.
* We just register these (as with normal frames) and throw them away.
* 3) Allow different MAC addresses for the two slave interfaces, using the
* MacAddressA field.
static bool is_supervision_frame(struct hsr_priv *hsr, struct sk_buff *skb)
struct hsr_ethhdr_sp *hdr;
hdr = (struct hsr_ethhdr_sp *) skb_mac_header(skb);
if (!ether_addr_equal(hdr->ethhdr.h_dest,
return false;
if (get_hsr_stag_path(&hdr->hsr_sup) != 0x0f)
return false;
if ((hdr->hsr_sup.HSR_TLV_Type != HSR_TLV_ANNOUNCE) &&
(hdr->hsr_sup.HSR_TLV_Type != HSR_TLV_LIFE_CHECK))
return false;
if (hdr->hsr_sup.HSR_TLV_Length != 12)
return false;
return true;
static struct sk_buff *create_stripped_skb(struct sk_buff *skb_in,
struct hsr_frame_info *frame)
struct sk_buff *skb;
int copylen;
unsigned char *dst, *src;
skb_pull(skb_in, HSR_HLEN);
skb = __pskb_copy(skb_in, skb_headroom(skb_in) - HSR_HLEN, GFP_ATOMIC);
skb_push(skb_in, HSR_HLEN);
if (skb == NULL)
return NULL;
if (skb->ip_summed == CHECKSUM_PARTIAL)
skb->csum_start -= HSR_HLEN;
copylen = 2*ETH_ALEN;
if (frame->is_vlan)
copylen += VLAN_HLEN;
src = skb_mac_header(skb_in);
dst = skb_mac_header(skb);
memcpy(dst, src, copylen);
skb->protocol = eth_hdr(skb)->h_proto;
return skb;
static struct sk_buff *frame_get_stripped_skb(struct hsr_frame_info *frame,
struct hsr_port *port)
if (!frame->skb_std)
frame->skb_std = create_stripped_skb(frame->skb_hsr, frame);
return skb_clone(frame->skb_std, GFP_ATOMIC);
static void hsr_fill_tag(struct sk_buff *skb, struct hsr_frame_info *frame,
struct hsr_port *port)
struct hsr_ethhdr *hsr_ethhdr;
int lane_id;
int lsdu_size;
if (port->type == HSR_PT_SLAVE_A)
lane_id = 0;
lane_id = 1;
lsdu_size = skb->len - 14;
if (frame->is_vlan)
lsdu_size -= 4;
hsr_ethhdr = (struct hsr_ethhdr *) skb_mac_header(skb);
set_hsr_tag_path(&hsr_ethhdr->hsr_tag, lane_id);
set_hsr_tag_LSDU_size(&hsr_ethhdr->hsr_tag, lsdu_size);
hsr_ethhdr->hsr_tag.sequence_nr = htons(frame->sequence_nr);
hsr_ethhdr->hsr_tag.encap_proto = hsr_ethhdr->ethhdr.h_proto;
hsr_ethhdr->ethhdr.h_proto = htons(ETH_P_PRP);
static struct sk_buff *create_tagged_skb(struct sk_buff *skb_o,
struct hsr_frame_info *frame,
struct hsr_port *port)
int movelen;
unsigned char *dst, *src;
struct sk_buff *skb;
/* Create the new skb with enough headroom to fit the HSR tag */
skb = __pskb_copy(skb_o, skb_headroom(skb_o) + HSR_HLEN, GFP_ATOMIC);
if (skb == NULL)
return NULL;
if (skb->ip_summed == CHECKSUM_PARTIAL)
skb->csum_start += HSR_HLEN;
movelen = ETH_HLEN;
if (frame->is_vlan)
movelen += VLAN_HLEN;
src = skb_mac_header(skb);
dst = skb_push(skb, HSR_HLEN);
memmove(dst, src, movelen);
hsr_fill_tag(skb, frame, port);
return skb;
/* If the original frame was an HSR tagged frame, just clone it to be sent
* unchanged. Otherwise, create a private frame especially tagged for 'port'.
static struct sk_buff *frame_get_tagged_skb(struct hsr_frame_info *frame,
struct hsr_port *port)
if (frame->skb_hsr)
return skb_clone(frame->skb_hsr, GFP_ATOMIC);
if ((port->type != HSR_PT_SLAVE_A) && (port->type != HSR_PT_SLAVE_B)) {
WARN_ONCE(1, "HSR: Bug: trying to create a tagged frame for a non-ring port");
return NULL;
return create_tagged_skb(frame->skb_std, frame, port);
static void hsr_deliver_master(struct sk_buff *skb, struct net_device *dev,
struct hsr_node *node_src)
bool was_multicast_frame;
int res;
was_multicast_frame = (skb->pkt_type == PACKET_MULTICAST);
hsr_addr_subst_source(node_src, skb);
skb_pull(skb, ETH_HLEN);
res = netif_rx(skb);
if (res == NET_RX_DROP) {
} else {
dev->stats.rx_bytes += skb->len;
if (was_multicast_frame)
static int hsr_xmit(struct sk_buff *skb, struct hsr_port *port,
struct hsr_frame_info *frame)
if (frame->port_rcv->type == HSR_PT_MASTER) {
hsr_addr_subst_dest(frame->node_src, skb, port);
/* Address substitution (IEC62439-3 pp 26, 50): replace mac
* address of outgoing frame with that of the outgoing slave's.
ether_addr_copy(eth_hdr(skb)->h_source, port->dev->dev_addr);
return dev_queue_xmit(skb);
/* Forward the frame through all devices except:
* - Back through the receiving device
* - If it's a HSR frame: through a device where it has passed before
* - To the local HSR master only if the frame is directly addressed to it, or
* a non-supervision multicast or broadcast frame.
* HSR slave devices should insert a HSR tag into the frame, or forward the
* frame unchanged if it's already tagged. Interlink devices should strip HSR
* tags if they're of the non-HSR type (but only after duplicate discard). The
* master device always strips HSR tags.
static void hsr_forward_do(struct hsr_frame_info *frame)
struct hsr_port *port;
struct sk_buff *skb;
hsr_for_each_port(frame->port_rcv->hsr, port) {
/* Don't send frame back the way it came */
if (port == frame->port_rcv)
/* Don't deliver locally unless we should */
if ((port->type == HSR_PT_MASTER) && !frame->is_local_dest)
/* Deliver frames directly addressed to us to master only */
if ((port->type != HSR_PT_MASTER) && frame->is_local_exclusive)
/* Don't send frame over port where it has been sent before */
if (hsr_register_frame_out(port, frame->node_src,
if (frame->is_supervision && (port->type == HSR_PT_MASTER)) {
if (port->type != HSR_PT_MASTER)
skb = frame_get_tagged_skb(frame, port);
skb = frame_get_stripped_skb(frame, port);
if (skb == NULL) {
/* FIXME: Record the dropped frame? */
skb->dev = port->dev;
if (port->type == HSR_PT_MASTER)
hsr_deliver_master(skb, port->dev, frame->node_src);
hsr_xmit(skb, port, frame);
static void check_local_dest(struct hsr_priv *hsr, struct sk_buff *skb,
struct hsr_frame_info *frame)
struct net_device *master_dev;
master_dev = hsr_port_get_hsr(hsr, HSR_PT_MASTER)->dev;
if (hsr_addr_is_self(hsr, eth_hdr(skb)->h_dest)) {
frame->is_local_exclusive = true;
skb->pkt_type = PACKET_HOST;
} else {
frame->is_local_exclusive = false;
if ((skb->pkt_type == PACKET_HOST) ||
(skb->pkt_type == PACKET_MULTICAST) ||
(skb->pkt_type == PACKET_BROADCAST)) {
frame->is_local_dest = true;
} else {
frame->is_local_dest = false;
static int hsr_fill_frame_info(struct hsr_frame_info *frame,
struct sk_buff *skb, struct hsr_port *port)
struct ethhdr *ethhdr;
unsigned long irqflags;
frame->is_supervision = is_supervision_frame(port->hsr, skb);
frame->node_src = hsr_get_node(&port->hsr->node_db, skb,
if (frame->node_src == NULL)
return -1; /* Unknown node and !is_supervision, or no mem */
ethhdr = (struct ethhdr *) skb_mac_header(skb);
frame->is_vlan = false;
if (ethhdr->h_proto == htons(ETH_P_8021Q)) {
frame->is_vlan = true;
/* FIXME: */
WARN_ONCE(1, "HSR: VLAN not yet supported");
if (ethhdr->h_proto == htons(ETH_P_PRP)) {
frame->skb_std = NULL;
frame->skb_hsr = skb;
frame->sequence_nr = hsr_get_skb_sequence_nr(skb);
} else {
frame->skb_std = skb;
frame->skb_hsr = NULL;
/* Sequence nr for the master node */
spin_lock_irqsave(&port->hsr->seqnr_lock, irqflags);
frame->sequence_nr = port->hsr->sequence_nr;
spin_unlock_irqrestore(&port->hsr->seqnr_lock, irqflags);
frame->port_rcv = port;
check_local_dest(port->hsr, skb, frame);
return 0;
/* Must be called holding rcu read lock (because of the port parameter) */
void hsr_forward_skb(struct sk_buff *skb, struct hsr_port *port)
struct hsr_frame_info frame;
if (skb_mac_header(skb) != skb->data) {
WARN_ONCE(1, "%s:%d: Malformed frame (port_src %s)\n",
__FILE__, __LINE__, port->dev->name);
goto out_drop;
if (hsr_fill_frame_info(&frame, skb, port) < 0)
goto out_drop;
hsr_register_frame_in(frame.node_src, port, frame.sequence_nr);
if (frame.skb_hsr != NULL)
if (frame.skb_std != NULL)