Subject: [PATCH net-next] net/hsr: Added support for HSR v1

From: Peter Heise <[email-masked]>
Date: Wed, 13 Apr 2016 13:52:22 +0200

This patch adds support for the newer version 1 of the HSR
networking standard. Version 0 is still default and the new
version has to be selected via iproute2.

Main changes are in the supervision frame handling and its
ethertype field.

Signed-off-by: Peter Heise <[email-masked]>
---
 include/uapi/linux/if_ether.h |  1 +
 include/uapi/linux/if_link.h  |  1 +
 net/hsr/Kconfig               |  5 +--
 net/hsr/hsr_device.c          | 80 +++++++++++++++++++++++++------------------
 net/hsr/hsr_device.h          |  2 +-
 net/hsr/hsr_forward.c         | 43 +++++++++++++++++------
 net/hsr/hsr_framereg.c        | 30 ++++++++++------
 net/hsr/hsr_main.h            | 13 ++++++-
 net/hsr/hsr_netlink.c         | 10 ++++--
 net/hsr/hsr_slave.c           |  4 ++-
 10 files changed, 126 insertions(+), 63 deletions(-)

diff --git a/include/uapi/linux/if_ether.h b/include/uapi/linux/if_ether.h
index 4a93051..cec849a 100644
--- a/include/uapi/linux/if_ether.h
+++ b/include/uapi/linux/if_ether.h
@@ -92,6 +92,7 @@
 #define ETH_P_TDLS	0x890D          /* TDLS */
 #define ETH_P_FIP	0x8914		/* FCoE Initialization Protocol */
 #define ETH_P_80221	0x8917		/* IEEE 802.21 Media Independent Handover Protocol */
+#define ETH_P_HSR	0x892F		/* IEC 62439-3 HSRv1	*/
 #define ETH_P_LOOPBACK	0x9000		/* Ethernet loopback packet, per IEEE 802.3 */
 #define ETH_P_QINQ1	0x9100		/* deprecated QinQ VLAN [ NOT AN OFFICIALLY REGISTERED ID ] */
 #define ETH_P_QINQ2	0x9200		/* deprecated QinQ VLAN [ NOT AN OFFICIALLY REGISTERED ID ] */
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 9427f17..bb3a90b 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -773,6 +773,7 @@ enum {
 	IFLA_HSR_SLAVE1,
 	IFLA_HSR_SLAVE2,
 	IFLA_HSR_MULTICAST_SPEC,	/* Last byte of supervision addr */
+	IFLA_HSR_VERSION,		/* HSR version */
 	IFLA_HSR_SUPERVISION_ADDR,	/* Supervision frame multicast addr */
 	IFLA_HSR_SEQ_NR,
 	__IFLA_HSR_MAX,
diff --git a/net/hsr/Kconfig b/net/hsr/Kconfig
index 0d3d709..4b683fd 100644
--- a/net/hsr/Kconfig
+++ b/net/hsr/Kconfig
@@ -18,8 +18,9 @@ config HSR
 	  earlier.
 
 	  This code is a "best effort" to comply with the HSR standard as
-	  described in IEC 62439-3:2010 (HSRv0), but no compliancy tests have
-	  been made.
+	  described in IEC 62439-3:2010 (HSRv0) and IEC 62439-3:2012 (HSRv1),
+	  but no compliancy tests have been made. Use iproute2 to select
+	  the version you desire.
 
 	  You need to perform any and all necessary tests yourself before
 	  relying on this code in a safety critical system!
diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c
index c7d1adc..386cbce 100644
--- a/net/hsr/hsr_device.c
+++ b/net/hsr/hsr_device.c
@@ -90,7 +90,8 @@ static void hsr_check_announce(struct net_device *hsr_dev,
 
 	hsr = netdev_priv(hsr_dev);
 
-	if ((hsr_dev->operstate == IF_OPER_UP) && (old_operstate != IF_OPER_UP)) {
+	if ((hsr_dev->operstate == IF_OPER_UP)
+			&& (old_operstate != IF_OPER_UP)) {
 		/* Went up */
 		hsr->announce_count = 0;
 		hsr->announce_timer.expires = jiffies +
@@ -250,31 +251,22 @@ static const struct header_ops hsr_header_ops = {
 	.parse	 = eth_header_parse,
 };
 
-
-/* HSR:2010 supervision frames should be padded so that the whole frame,
- * including headers and FCS, is 64 bytes (without VLAN).
- */
-static int hsr_pad(int size)
-{
-	const int min_size = ETH_ZLEN - HSR_HLEN - ETH_HLEN;
-
-	if (size >= min_size)
-		return size;
-	return min_size;
-}
-
-static void send_hsr_supervision_frame(struct hsr_port *master, u8 type)
+static void send_hsr_supervision_frame(struct hsr_port *master,
+		u8 type, u8 hsrVer)
 {
 	struct sk_buff *skb;
 	int hlen, tlen;
+	struct hsr_tag *hsr_tag;
 	struct hsr_sup_tag *hsr_stag;
 	struct hsr_sup_payload *hsr_sp;
 	unsigned long irqflags;
 
 	hlen = LL_RESERVED_SPACE(master->dev);
 	tlen = master->dev->needed_tailroom;
-	skb = alloc_skb(hsr_pad(sizeof(struct hsr_sup_payload)) + hlen + tlen,
-			GFP_ATOMIC);
+	skb = dev_alloc_skb(
+			sizeof(struct hsr_tag) +
+			sizeof(struct hsr_sup_tag) +
+			sizeof(struct hsr_sup_payload) + hlen + tlen);
 
 	if (skb == NULL)
 		return;
@@ -282,32 +274,48 @@ static void send_hsr_supervision_frame(struct hsr_port *master, u8 type)
 	skb_reserve(skb, hlen);
 
 	skb->dev = master->dev;
-	skb->protocol = htons(ETH_P_PRP);
+	skb->protocol = htons(hsrVer ? ETH_P_HSR : ETH_P_PRP);
 	skb->priority = TC_PRIO_CONTROL;
 
-	if (dev_hard_header(skb, skb->dev, ETH_P_PRP,
+	if (dev_hard_header(skb, skb->dev, (hsrVer ? ETH_P_HSR : ETH_P_PRP),
 			    master->hsr->sup_multicast_addr,
 			    skb->dev->dev_addr, skb->len) <= 0)
 		goto out;
 	skb_reset_mac_header(skb);
 
-	hsr_stag = (typeof(hsr_stag)) skb_put(skb, sizeof(*hsr_stag));
+	if (hsrVer > 0) {
+		hsr_tag = (typeof(hsr_tag)) skb_put(skb, sizeof(struct hsr_tag));
+		hsr_tag->encap_proto = htons(ETH_P_PRP);
+		set_hsr_tag_LSDU_size(hsr_tag, HSR_V1_SUP_LSDUSIZE);
+	}
 
-	set_hsr_stag_path(hsr_stag, 0xf);
-	set_hsr_stag_HSR_Ver(hsr_stag, 0);
+	hsr_stag = (typeof(hsr_stag)) skb_put(skb, sizeof(struct hsr_sup_tag));
+	set_hsr_stag_path(hsr_stag, (hsrVer ? 0x0 : 0xf));
+	set_hsr_stag_HSR_Ver(hsr_stag, hsrVer);
 
+	/* From HSRv1 on we have separate supervision sequence numbers. */
 	spin_lock_irqsave(&master->hsr->seqnr_lock, irqflags);
-	hsr_stag->sequence_nr = htons(master->hsr->sequence_nr);
-	master->hsr->sequence_nr++;
+	if (hsrVer > 0) {
+		hsr_stag->sequence_nr = htons(master->hsr->sup_sequence_nr);
+		hsr_tag->sequence_nr = htons(master->hsr->sequence_nr);
+		master->hsr->sup_sequence_nr++;
+		master->hsr->sequence_nr++;
+	} else {
+		hsr_stag->sequence_nr = htons(master->hsr->sequence_nr);
+		master->hsr->sequence_nr++;
+	}
 	spin_unlock_irqrestore(&master->hsr->seqnr_lock, irqflags);
 
 	hsr_stag->HSR_TLV_Type = type;
-	hsr_stag->HSR_TLV_Length = 12;
+	/* TODO: Why 12 in HSRv0? */
+	hsr_stag->HSR_TLV_Length = hsrVer ? sizeof(struct hsr_sup_payload) : 12;
 
 	/* Payload: MacAddressA */
-	hsr_sp = (typeof(hsr_sp)) skb_put(skb, sizeof(*hsr_sp));
+	hsr_sp = (typeof(hsr_sp)) skb_put(skb, sizeof(struct hsr_sup_payload));
 	ether_addr_copy(hsr_sp->MacAddressA, master->dev->dev_addr);
 
+	skb_put_padto(skb, ETH_ZLEN + HSR_HLEN);
+
 	hsr_forward_skb(skb, master);
 	return;
 
@@ -329,19 +337,20 @@ static void hsr_announce(unsigned long data)
 	rcu_read_lock();
 	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
 
-	if (hsr->announce_count < 3) {
-		send_hsr_supervision_frame(master, HSR_TLV_ANNOUNCE);
+	if (hsr->announce_count < 3 && hsr->protVersion == 0) {
+		send_hsr_supervision_frame(master, HSR_TLV_ANNOUNCE,
+				hsr->protVersion);
 		hsr->announce_count++;
-	} else {
-		send_hsr_supervision_frame(master, HSR_TLV_LIFE_CHECK);
-	}
 
-	if (hsr->announce_count < 3)
 		hsr->announce_timer.expires = jiffies +
 				msecs_to_jiffies(HSR_ANNOUNCE_INTERVAL);
-	else
+	} else {
+		send_hsr_supervision_frame(master, HSR_TLV_LIFE_CHECK,
+				hsr->protVersion);
+
 		hsr->announce_timer.expires = jiffies +
 				msecs_to_jiffies(HSR_LIFE_CHECK_INTERVAL);
+	}
 
 	if (is_admin_up(master->dev))
 		add_timer(&hsr->announce_timer);
@@ -428,7 +437,7 @@ static const unsigned char def_multicast_addr[ETH_ALEN] __aligned(2) = {
 };
 
 int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
-		     unsigned char multicast_spec)
+		     unsigned char multicast_spec, u8 protocol_version)
 {
 	struct hsr_priv *hsr;
 	struct hsr_port *port;
@@ -450,6 +459,7 @@ int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
 	spin_lock_init(&hsr->seqnr_lock);
 	/* Overflow soon to find bugs easier: */
 	hsr->sequence_nr = HSR_SEQNR_START;
+	hsr->sup_sequence_nr = HSR_SUP_SEQNR_START;
 
 	init_timer(&hsr->announce_timer);
 	hsr->announce_timer.function = hsr_announce;
@@ -462,6 +472,8 @@ int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
 	ether_addr_copy(hsr->sup_multicast_addr, def_multicast_addr);
 	hsr->sup_multicast_addr[ETH_ALEN - 1] = multicast_spec;
 
+	hsr->protVersion = protocol_version;
+
 	/* FIXME: should I modify the value of these?
 	 *
 	 * - hsr_dev->flags - i.e.
diff --git a/net/hsr/hsr_device.h b/net/hsr/hsr_device.h
index 108a5d5..9975e31 100644
--- a/net/hsr/hsr_device.h
+++ b/net/hsr/hsr_device.h
@@ -17,7 +17,7 @@
 
 void hsr_dev_setup(struct net_device *dev);
 int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
-		     unsigned char multicast_spec);
+		     unsigned char multicast_spec, u8 protocol_version);
 void hsr_check_carrier_and_operstate(struct hsr_priv *hsr);
 bool is_hsr_master(struct net_device *dev);
 int hsr_get_max_mtu(struct hsr_priv *hsr);
diff --git a/net/hsr/hsr_forward.c b/net/hsr/hsr_forward.c
index 7871ed6..5ee1d43 100644
--- a/net/hsr/hsr_forward.c
+++ b/net/hsr/hsr_forward.c
@@ -50,21 +50,40 @@ struct hsr_frame_info {
  */
 static bool is_supervision_frame(struct hsr_priv *hsr, struct sk_buff *skb)
 {
-	struct hsr_ethhdr_sp *hdr;
+	struct ethhdr *ethHdr;
+	struct hsr_sup_tag *hsrSupTag;
+	struct hsrv1_ethhdr_sp *hsrV1Hdr;
 
 	WARN_ON_ONCE(!skb_mac_header_was_set(skb));
-	hdr = (struct hsr_ethhdr_sp *) skb_mac_header(skb);
+	ethHdr = (struct ethhdr *) skb_mac_header(skb);
 
-	if (!ether_addr_equal(hdr->ethhdr.h_dest,
+	/* Correct addr? */
+	if (!ether_addr_equal(ethHdr->h_dest,
 			      hsr->sup_multicast_addr))
 		return false;
 
-	if (get_hsr_stag_path(&hdr->hsr_sup) != 0x0f)
+	/* Correct ether type?. */
+	if (!(ethHdr->h_proto == htons(ETH_P_PRP)
+			|| ethHdr->h_proto == htons(ETH_P_HSR)))
 		return false;
-	if ((hdr->hsr_sup.HSR_TLV_Type != HSR_TLV_ANNOUNCE) &&
-	    (hdr->hsr_sup.HSR_TLV_Type != HSR_TLV_LIFE_CHECK))
+
+	/* Get the supervision header from correct location. */
+	if (ethHdr->h_proto == htons(ETH_P_HSR)) { /* Okay HSRv1. */
+		hsrV1Hdr = (struct hsrv1_ethhdr_sp *) skb_mac_header(skb);
+		if (hsrV1Hdr->hsr.encap_proto != htons(ETH_P_PRP))
+			return false;
+
+		hsrSupTag = &hsrV1Hdr->hsr_sup;
+	} else {
+		hsrSupTag = &((struct hsrv0_ethhdr_sp *) skb_mac_header(skb))->hsr_sup;
+	}
+
+	if ((hsrSupTag->HSR_TLV_Type != HSR_TLV_ANNOUNCE) &&
+	    (hsrSupTag->HSR_TLV_Type != HSR_TLV_LIFE_CHECK))
 		return false;
-	if (hdr->hsr_sup.HSR_TLV_Length != 12)
+	if ((hsrSupTag->HSR_TLV_Length != 12) &&
+			(hsrSupTag->HSR_TLV_Length !=
+					sizeof(struct hsr_sup_payload)))
 		return false;
 
 	return true;
@@ -110,7 +129,7 @@ static struct sk_buff *frame_get_stripped_skb(struct hsr_frame_info *frame,

 static void hsr_fill_tag(struct sk_buff *skb, struct hsr_frame_info *frame,
-			 struct hsr_port *port)
+			 struct hsr_port *port, u8 protoVersion)
 {
 	struct hsr_ethhdr *hsr_ethhdr;
 	int lane_id;
@@ -131,7 +150,8 @@ static void hsr_fill_tag(struct sk_buff *skb, struct hsr_frame_info *frame,
 	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);
+	hsr_ethhdr->ethhdr.h_proto = htons(protoVersion ?
+			ETH_P_HSR : ETH_P_PRP);
 }
 
 static struct sk_buff *create_tagged_skb(struct sk_buff *skb_o,
@@ -160,7 +180,7 @@ static struct sk_buff *create_tagged_skb(struct sk_buff *skb_o,
 	memmove(dst, src, movelen);
 	skb_reset_mac_header(skb);
 
-	hsr_fill_tag(skb, frame, port);
+	hsr_fill_tag(skb, frame, port, port->hsr->protVersion);
 
 	return skb;
 }
@@ -320,7 +340,8 @@ static int hsr_fill_frame_info(struct hsr_frame_info *frame,
 		/* FIXME: */
 		WARN_ONCE(1, "HSR: VLAN not yet supported");
 	}
-	if (ethhdr->h_proto == htons(ETH_P_PRP)) {
+	if (ethhdr->h_proto == htons(ETH_P_PRP)
+			|| ethhdr->h_proto == htons(ETH_P_HSR)) {
 		frame->skb_std = NULL;
 		frame->skb_hsr = skb;
 		frame->sequence_nr = hsr_get_skb_sequence_nr(skb);
diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c
index bace124..7ea9258 100644
--- a/net/hsr/hsr_framereg.c
+++ b/net/hsr/hsr_framereg.c
@@ -177,17 +177,17 @@ struct hsr_node *hsr_get_node(struct list_head *node_db, struct sk_buff *skb,
 			return node;
 	}
 
-	if (!is_sup)
-		return NULL; /* Only supervision frame may create node entry */
+	/* Everyone may create a node entry, connected node to a HSR device. */
 
-	if (ethhdr->h_proto == htons(ETH_P_PRP)) {
+	if (ethhdr->h_proto == htons(ETH_P_PRP)
+			|| ethhdr->h_proto == htons(ETH_P_HSR)) {
 		/* Use the existing sequence_nr from the tag as starting point
 		 * for filtering duplicate frames.
 		 */
 		seq_out = hsr_get_skb_sequence_nr(skb) - 1;
 	} else {
 		WARN_ONCE(1, "%s: Non-HSR frame\n", __func__);
-		seq_out = 0;
+		seq_out = HSR_SEQNR_START;
 	}
 
 	return hsr_add_node(node_db, ethhdr->h_source, seq_out);
@@ -200,17 +200,25 @@ struct hsr_node *hsr_get_node(struct list_head *node_db, struct sk_buff *skb,
 void hsr_handle_sup_frame(struct sk_buff *skb, struct hsr_node *node_curr,
 			  struct hsr_port *port_rcv)
 {
+	struct ethhdr *ethhdr;
 	struct hsr_node *node_real;
 	struct hsr_sup_payload *hsr_sp;
 	struct list_head *node_db;
 	int i;
 
-	skb_pull(skb, sizeof(struct hsr_ethhdr_sp));
-	hsr_sp = (struct hsr_sup_payload *) skb->data;
+	ethhdr = (struct ethhdr *) skb_mac_header(skb);
 
-	if (ether_addr_equal(eth_hdr(skb)->h_source, hsr_sp->MacAddressA))
-		/* Not sent from MacAddressB of a PICS_SUBS capable node */
-		goto done;
+	/* Leave the ethernet header. */
+	skb_pull(skb, sizeof(struct ethhdr));
+
+	/* And leave the HSR tag. */
+	if (ethhdr->h_proto == htons(ETH_P_HSR))
+		skb_pull(skb, sizeof(struct hsr_tag));
+
+	/* And leave the HSR sup tag. */
+	skb_pull(skb, sizeof(struct hsr_sup_tag));
+
+	hsr_sp = (struct hsr_sup_payload *) skb->data;
 
 	/* Merge node_curr (registered on MacAddressB) into node_real */
 	node_db = &port_rcv->hsr->node_db;
@@ -225,7 +233,7 @@ void hsr_handle_sup_frame(struct sk_buff *skb, struct hsr_node *node_curr,
 		/* Node has already been merged */
 		goto done;
 
-	ether_addr_copy(node_real->MacAddressB, eth_hdr(skb)->h_source);
+	ether_addr_copy(node_real->MacAddressB, ethhdr->h_source);
 	for (i = 0; i < HSR_PT_PORTS; i++) {
 		if (!node_curr->time_in_stale[i] &&
 		    time_after(node_curr->time_in[i], node_real->time_in[i])) {
@@ -241,7 +249,7 @@ void hsr_handle_sup_frame(struct sk_buff *skb, struct hsr_node *node_curr,
 	kfree_rcu(node_curr, rcu_head);
 
 done:
-	skb_push(skb, sizeof(struct hsr_ethhdr_sp));
+	skb_push(skb, sizeof(struct hsrv1_ethhdr_sp));
 }

diff --git a/net/hsr/hsr_main.h b/net/hsr/hsr_main.h
index 5a9c699..9b9909e 100644
--- a/net/hsr/hsr_main.h
+++ b/net/hsr/hsr_main.h
@@ -30,6 +30,7 @@
  */
 #define MAX_SLAVE_DIFF			 3000 /* ms */
 #define HSR_SEQNR_START			(USHRT_MAX - 1024)
+#define HSR_SUP_SEQNR_START		(HSR_SEQNR_START / 2)

 /* How often shall we check for broken ring and remove node entries older than
@@ -58,6 +59,8 @@ struct hsr_tag {
 
 #define HSR_HLEN	6
 
+#define HSR_V1_SUP_LSDUSIZE		52
+
 /* The helper functions below assumes that 'path' occupies the 4 most
  * significant bits of the 16-bit field shared by 'path' and 'LSDU_size' (or
  * equivalently, the 4 most significant bits of HSR tag byte 14).
@@ -131,8 +134,14 @@ static inline void set_hsr_stag_HSR_Ver(struct hsr_sup_tag *hst, u16 HSR_Ver)
 	set_hsr_tag_LSDU_size((struct hsr_tag *) hst, HSR_Ver);
 }
 
-struct hsr_ethhdr_sp {
+struct hsrv0_ethhdr_sp {
+	struct ethhdr		ethhdr;
+	struct hsr_sup_tag	hsr_sup;
+} __packed;
+
+struct hsrv1_ethhdr_sp {
 	struct ethhdr		ethhdr;
+	struct hsr_tag		hsr;
 	struct hsr_sup_tag	hsr_sup;
 } __packed;
 
@@ -162,6 +171,8 @@ struct hsr_priv {
 	struct timer_list	prune_timer;
 	int announce_count;
 	u16 sequence_nr;
+	u16 sup_sequence_nr;			/* For HSRv1 separate seq_nr for supervision */
+	u8 protVersion;					/* Indicate if HSRv0 or HSRv1. */
 	spinlock_t seqnr_lock;			/* locking for sequence_nr */
 	unsigned char		sup_multicast_addr[ETH_ALEN];
 };
diff --git a/net/hsr/hsr_netlink.c b/net/hsr/hsr_netlink.c
index a2c7e4c..5425d87 100644
--- a/net/hsr/hsr_netlink.c
+++ b/net/hsr/hsr_netlink.c
@@ -23,6 +23,7 @@ static const struct nla_policy hsr_policy[IFLA_HSR_MAX + 1] = {
 	[IFLA_HSR_SLAVE1]		= { .type = NLA_U32 },
 	[IFLA_HSR_SLAVE2]		= { .type = NLA_U32 },
 	[IFLA_HSR_MULTICAST_SPEC]	= { .type = NLA_U8 },
+	[IFLA_HSR_VERSION]	= { .type = NLA_U8 },
 	[IFLA_HSR_SUPERVISION_ADDR]	= { .type = NLA_BINARY, .len = ETH_ALEN },
 	[IFLA_HSR_SEQ_NR]		= { .type = NLA_U16 },
 };
@@ -35,7 +36,7 @@ static int hsr_newlink(struct net *src_net, struct net_device *dev,
 		       struct nlattr *tb[], struct nlattr *data[])
 {
 	struct net_device *link[2];
-	unsigned char multicast_spec;
+	unsigned char multicast_spec, hsr_version;
 
 	if (!data) {
 		netdev_info(dev, "HSR: No slave devices specified\n");
@@ -62,7 +63,12 @@ static int hsr_newlink(struct net *src_net, struct net_device *dev,
 	else
 		multicast_spec = nla_get_u8(data[IFLA_HSR_MULTICAST_SPEC]);
 
-	return hsr_dev_finalize(dev, link, multicast_spec);
+	if (!data[IFLA_HSR_VERSION])
+		hsr_version = 0;
+	else
+		hsr_version = nla_get_u8(data[IFLA_HSR_VERSION]);
+
+	return hsr_dev_finalize(dev, link, multicast_spec, hsr_version);
 }
 
 static int hsr_fill_info(struct sk_buff *skb, const struct net_device *dev)
diff --git a/net/hsr/hsr_slave.c b/net/hsr/hsr_slave.c
index 7d37366..f5b6038 100644
--- a/net/hsr/hsr_slave.c
+++ b/net/hsr/hsr_slave.c
@@ -22,6 +22,7 @@ static rx_handler_result_t hsr_handle_frame(struct sk_buff **pskb)
 {
 	struct sk_buff *skb = *pskb;
 	struct hsr_port *port;
+	u16 protocol;
 
 	if (!skb_mac_header_was_set(skb)) {
 		WARN_ONCE(1, "%s: skb invalid", __func__);
@@ -37,7 +38,8 @@ static rx_handler_result_t hsr_handle_frame(struct sk_buff **pskb)
 		goto finish_consume;
 	}
 
-	if (eth_hdr(skb)->h_proto != htons(ETH_P_PRP))
+	protocol = eth_hdr(skb)->h_proto;
+	if (protocol != htons(ETH_P_PRP) && protocol != htons(ETH_P_HSR))
 		goto finish_pass;
 
 	skb_push(skb, ETH_HLEN);
-- 
2.5.0