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, 75 insertions, 19 deletions

diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c
index 13b2190e6556..5c97de459905 100644
--- a/net/hsr/hsr_framereg.c
+++ b/net/hsr/hsr_framereg.c
@@ -127,6 +127,19 @@ void hsr_del_nodes(struct list_head *node_db)
 		kfree(node);
 }
 
+void prp_handle_san_frame(bool san, enum hsr_port_type port,
+			  struct hsr_node *node)
+{
+	/* Mark if the SAN node is over LAN_A or LAN_B */
+	if (port == HSR_PT_SLAVE_A) {
+		node->san_a = true;
+		return;
+	}
+
+	if (port == HSR_PT_SLAVE_B)
+		node->san_b = true;
+}
+
 /* Allocate an hsr_node and add it to node_db. 'addr' is the node's address_A;
  * seq_out is used to initialize filtering of outgoing duplicate frames
  * originating from the newly added node.
@@ -134,7 +147,8 @@ void hsr_del_nodes(struct list_head *node_db)
 static struct hsr_node *hsr_add_node(struct hsr_priv *hsr,
 				     struct list_head *node_db,
 				     unsigned char addr[],
-				     u16 seq_out)
+				     u16 seq_out, bool san,
+				     enum hsr_port_type rx_port)
 {
 	struct hsr_node *new_node, *node;
 	unsigned long now;
@@ -155,6 +169,9 @@ static struct hsr_node *hsr_add_node(struct hsr_priv *hsr,
 	for (i = 0; i < HSR_PT_PORTS; i++)
 		new_node->seq_out[i] = seq_out;
 
+	if (san && hsr->proto_ops->handle_san_frame)
+		hsr->proto_ops->handle_san_frame(san, rx_port, new_node);
+
 	spin_lock_bh(&hsr->list_lock);
 	list_for_each_entry_rcu(node, node_db, mac_list,
 				lockdep_is_held(&hsr->list_lock)) {
@@ -172,15 +189,26 @@ out:
 	return node;
 }
 
+void prp_update_san_info(struct hsr_node *node, bool is_sup)
+{
+	if (!is_sup)
+		return;
+
+	node->san_a = false;
+	node->san_b = false;
+}
+
 /* Get the hsr_node from which 'skb' was sent.
  */
-struct hsr_node *hsr_get_node(struct hsr_port *port, struct sk_buff *skb,
-			      bool is_sup)
+struct hsr_node *hsr_get_node(struct hsr_port *port, struct list_head *node_db,
+			      struct sk_buff *skb, bool is_sup,
+			      enum hsr_port_type rx_port)
 {
-	struct list_head *node_db = &port->hsr->node_db;
 	struct hsr_priv *hsr = port->hsr;
 	struct hsr_node *node;
 	struct ethhdr *ethhdr;
+	struct prp_rct *rct;
+	bool san = false;
 	u16 seq_out;
 
 	if (!skb_mac_header_was_set(skb))
@@ -189,14 +217,21 @@ struct hsr_node *hsr_get_node(struct hsr_port *port, struct sk_buff *skb,
 	ethhdr = (struct ethhdr *)skb_mac_header(skb);
 
 	list_for_each_entry_rcu(node, node_db, mac_list) {
-		if (ether_addr_equal(node->macaddress_A, ethhdr->h_source))
+		if (ether_addr_equal(node->macaddress_A, ethhdr->h_source)) {
+			if (hsr->proto_ops->update_san_info)
+				hsr->proto_ops->update_san_info(node, is_sup);
 			return node;
-		if (ether_addr_equal(node->macaddress_B, ethhdr->h_source))
+		}
+		if (ether_addr_equal(node->macaddress_B, ethhdr->h_source)) {
+			if (hsr->proto_ops->update_san_info)
+				hsr->proto_ops->update_san_info(node, is_sup);
 			return node;
+		}
 	}
 
-	/* Everyone may create a node entry, connected node to a HSR device. */
-
+	/* Everyone may create a node entry, connected node to a HSR/PRP
+	 * device.
+	 */
 	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
@@ -204,31 +239,47 @@ struct hsr_node *hsr_get_node(struct hsr_port *port, struct sk_buff *skb,
 		 */
 		seq_out = hsr_get_skb_sequence_nr(skb) - 1;
 	} else {
-		/* this is called also for frames from master port and
-		 * so warn only for non master ports
-		 */
-		if (port->type != HSR_PT_MASTER)
-			WARN_ONCE(1, "%s: Non-HSR frame\n", __func__);
-		seq_out = HSR_SEQNR_START;
+		rct = skb_get_PRP_rct(skb);
+		if (rct && prp_check_lsdu_size(skb, rct, is_sup)) {
+			seq_out = prp_get_skb_sequence_nr(rct);
+		} else {
+			if (rx_port != HSR_PT_MASTER)
+				san = true;
+			seq_out = HSR_SEQNR_START;
+		}
 	}
 
-	return hsr_add_node(hsr, node_db, ethhdr->h_source, seq_out);
+	return hsr_add_node(hsr, node_db, ethhdr->h_source, seq_out,
+			    san, rx_port);
 }
 
 /* Use the Supervision frame's info about an eventual macaddress_B for merging
  * nodes that has previously had their macaddress_B registered as a separate
  * node.
  */
-void hsr_handle_sup_frame(struct sk_buff *skb, struct hsr_node *node_curr,
-			  struct hsr_port *port_rcv)
+void hsr_handle_sup_frame(struct hsr_frame_info *frame)
 {
+	struct hsr_node *node_curr = frame->node_src;
+	struct hsr_port *port_rcv = frame->port_rcv;
 	struct hsr_priv *hsr = port_rcv->hsr;
 	struct hsr_sup_payload *hsr_sp;
 	struct hsr_node *node_real;
+	struct sk_buff *skb = NULL;
 	struct list_head *node_db;
 	struct ethhdr *ethhdr;
 	int i;
 
+	/* Here either frame->skb_hsr or frame->skb_prp should be
+	 * valid as supervision frame always will have protocol
+	 * header info.
+	 */
+	if (frame->skb_hsr)
+		skb = frame->skb_hsr;
+	else if (frame->skb_prp)
+		skb = frame->skb_prp;
+	if (!skb)
+		return;
+
 	ethhdr = (struct ethhdr *)skb_mac_header(skb);
 
 	/* Leave the ethernet header. */
@@ -249,7 +300,8 @@ void hsr_handle_sup_frame(struct sk_buff *skb, struct hsr_node *node_curr,
 	if (!node_real)
 		/* No frame received from AddrA of this node yet */
 		node_real = hsr_add_node(hsr, node_db, hsr_sp->macaddress_A,
-					 HSR_SEQNR_START - 1);
+					 HSR_SEQNR_START - 1, true,
+					 port_rcv->type);
 	if (!node_real)
 		goto done; /* No mem */
 	if (node_real == node_curr)
@@ -275,7 +327,11 @@ 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 hsrv1_ethhdr_sp));
+	/* PRP uses v0 header */
+	if (ethhdr->h_proto == htons(ETH_P_HSR))
+		skb_push(skb, sizeof(struct hsrv1_ethhdr_sp));
+	else
+		skb_push(skb, sizeof(struct hsrv0_ethhdr_sp));
 }
 
 /* 'skb' is a frame meant for this host, that is to be passed to upper layers.