net: prp: add packet handling support

DAN-P (Dual Attached Nodes PRP) nodes are expected to receive
traditional IP packets as well as PRP (Parallel Redundancy
Protocol) tagged (trailer) packets. PRP trailer is 6 bytes
of PRP protocol unit called RCT, Redundancy Control Trailer
(RCT) similar to HSR tag. PRP network can have traditional
devices such as bridges/switches or PC attached to it and
should be able to communicate. Regular Ethernet devices treat
the RCT as pads.  This patch adds logic to format L2 frames
from network stack to add a trailer (RCT) and send it as
duplicates over the slave interfaces when the protocol is
PRP as per IEC 62439-3. At the ingress, it strips the trailer,
do duplicate detection and rejection and forward a stripped
frame up the network stack. PRP device should accept frames
from Singly Attached Nodes (SAN) and thus the driver mark
the link where the frame came from in the node table.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 72 insertions, 1 deletions

diff --git a/net/hsr/hsr_main.h b/net/hsr/hsr_main.h
index 14f442c57a84..7dc92ce5a134 100644
--- a/net/hsr/hsr_main.h
+++ b/net/hsr/hsr_main.h
@@ -12,6 +12,7 @@
 
 #include <linux/netdevice.h>
 #include <linux/list.h>
+#include <linux/if_vlan.h>
 
 /* Time constants as specified in the HSR specification (IEC-62439-3 2010)
  * Table 8.
@@ -86,7 +87,12 @@ struct hsr_ethhdr {
 	struct hsr_tag	hsr_tag;
 } __packed;
 
-/* HSR Supervision Frame data types.
+struct hsr_vlan_ethhdr {
+	struct vlan_ethhdr vlanhdr;
+	struct hsr_tag	hsr_tag;
+} __packed;
+
+/* HSR/PRP Supervision Frame data types.
  * Field names as defined in the IEC:2010 standard for HSR.
  */
 struct hsr_sup_tag {
@@ -142,6 +148,16 @@ struct prp_rct {
 	__be16          PRP_suffix;
 } __packed;
 
+static inline u16 get_prp_LSDU_size(struct prp_rct *rct)
+{
+	return ntohs(rct->lan_id_and_LSDU_size) & 0x0FFF;
+}
+
+static inline void set_prp_lan_id(struct prp_rct *rct, u16 lan_id)
+{
+	rct->lan_id_and_LSDU_size = htons((ntohs(rct->lan_id_and_LSDU_size) &
+					  0x0FFF) | (lan_id << 12));
+}
 static inline void set_prp_LSDU_size(struct prp_rct *rct, u16 LSDU_size)
 {
 	rct->lan_id_and_LSDU_size = htons((ntohs(rct->lan_id_and_LSDU_size) &
@@ -163,16 +179,22 @@ enum hsr_version {
 };
 
 struct hsr_frame_info;
+struct hsr_node;
 
 struct hsr_proto_ops {
 	/* format and send supervision frame */
 	void (*send_sv_frame)(struct hsr_port *port, unsigned long *interval);
+	void (*handle_san_frame)(bool san, enum hsr_port_type port,
+				 struct hsr_node *node);
+	bool (*drop_frame)(struct hsr_frame_info *frame, struct hsr_port *port);
 	struct sk_buff * (*get_untagged_frame)(struct hsr_frame_info *frame,
 					       struct hsr_port *port);
 	struct sk_buff * (*create_tagged_frame)(struct hsr_frame_info *frame,
 						struct hsr_port *port);
 	void (*fill_frame_info)(__be16 proto, struct sk_buff *skb,
 				struct hsr_frame_info *frame);
+	bool (*invalid_dan_ingress_frame)(__be16 protocol);
+	void (*update_san_info)(struct hsr_node *node, bool is_sup);
 };
 
 struct hsr_priv {
@@ -189,6 +211,12 @@ struct hsr_priv {
 	spinlock_t seqnr_lock;	/* locking for sequence_nr */
 	spinlock_t list_lock;	/* locking for node list */
 	struct hsr_proto_ops	*proto_ops;
+#define PRP_LAN_ID	0x5     /* 0x1010 for A and 0x1011 for B. Bit 0 is set
+				 * based on SLAVE_A or SLAVE_B
+				 */
+	u8 net_id;		/* for PRP, it occupies most significant 3 bits
+				 * of lan_id
+				 */
 	unsigned char		sup_multicast_addr[ETH_ALEN];
 #ifdef	CONFIG_DEBUG_FS
 	struct dentry *node_tbl_root;
@@ -209,6 +237,49 @@ static inline u16 hsr_get_skb_sequence_nr(struct sk_buff *skb)
 	return ntohs(hsr_ethhdr->hsr_tag.sequence_nr);
 }
 
+static inline struct prp_rct *skb_get_PRP_rct(struct sk_buff *skb)
+{
+	unsigned char *tail = skb_tail_pointer(skb) - HSR_HLEN;
+
+	struct prp_rct *rct = (struct prp_rct *)tail;
+
+	if (rct->PRP_suffix == htons(ETH_P_PRP))
+		return rct;
+
+	return NULL;
+}
+
+/* Assume caller has confirmed this skb is PRP suffixed */
+static inline u16 prp_get_skb_sequence_nr(struct prp_rct *rct)
+{
+	return ntohs(rct->sequence_nr);
+}
+
+static inline u16 get_prp_lan_id(struct prp_rct *rct)
+{
+	return ntohs(rct->lan_id_and_LSDU_size) >> 12;
+}
+
+/* assume there is a valid rct */
+static inline bool prp_check_lsdu_size(struct sk_buff *skb,
+				       struct prp_rct *rct,
+				       bool is_sup)
+{
+	struct ethhdr *ethhdr;
+	int expected_lsdu_size;
+
+	if (is_sup) {
+		expected_lsdu_size = HSR_V1_SUP_LSDUSIZE;
+	} else {
+		ethhdr = (struct ethhdr *)skb_mac_header(skb);
+		expected_lsdu_size = skb->len - 14;
+		if (ethhdr->h_proto == htons(ETH_P_8021Q))
+			expected_lsdu_size -= 4;
+	}
+
+	return (expected_lsdu_size == get_prp_LSDU_size(rct));
+}
+
 #if IS_ENABLED(CONFIG_DEBUG_FS)
 void hsr_debugfs_rename(struct net_device *dev);
 void hsr_debugfs_init(struct hsr_priv *priv, struct net_device *hsr_dev);