net/hsr: Switch from dev_add_pack() to netdev_rx_handler_register()

Also move the frame receive handler to hsr_slave.c.

Signed-off-by: Arvid Brodin <arvid.brodin@alten.se>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 243 insertions, 0 deletions

diff --git a/net/hsr/hsr_slave.c b/net/hsr/hsr_slave.c
new file mode 100644
index 000000000000..702814631ee1
--- /dev/null
+++ b/net/hsr/hsr_slave.c
@@ -0,0 +1,243 @@
+/* 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, arvid.brodin@alten.se
+ */
+
+#include "hsr_slave.h"
+#include <linux/etherdevice.h>
+#include "hsr_main.h"
+#include "hsr_framereg.h"
+
+
+static struct sk_buff *hsr_pull_tag(struct sk_buff *skb)
+{
+	struct hsr_tag *hsr_tag;
+	struct sk_buff *skb2;
+
+	skb2 = skb_share_check(skb, GFP_ATOMIC);
+	if (unlikely(!skb2))
+		goto err_free;
+	skb = skb2;
+
+	if (unlikely(!pskb_may_pull(skb, HSR_HLEN)))
+		goto err_free;
+
+	hsr_tag = (struct hsr_tag *) skb->data;
+	skb->protocol = hsr_tag->encap_proto;
+	skb_pull(skb, HSR_HLEN);
+
+	return skb;
+
+err_free:
+	kfree_skb(skb);
+	return NULL;
+}
+
+
+/* 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_sup_tag *hsr_stag;
+
+	if (!ether_addr_equal(eth_hdr(skb)->h_dest,
+			      hsr->sup_multicast_addr))
+		return false;
+
+	hsr_stag = (struct hsr_sup_tag *) skb->data;
+	if (get_hsr_stag_path(hsr_stag) != 0x0f)
+		return false;
+	if ((hsr_stag->HSR_TLV_Type != HSR_TLV_ANNOUNCE) &&
+	    (hsr_stag->HSR_TLV_Type != HSR_TLV_LIFE_CHECK))
+		return false;
+	if (hsr_stag->HSR_TLV_Length != 12)
+		return false;
+
+	return true;
+}
+
+
+/* Implementation somewhat according to IEC-62439-3, p. 43
+ */
+rx_handler_result_t hsr_handle_frame(struct sk_buff **pskb)
+{
+	struct sk_buff *skb = *pskb;
+	struct net_device *dev = skb->dev;
+	struct hsr_priv *hsr;
+	struct net_device *other_slave;
+	struct hsr_node *node;
+	bool deliver_to_self;
+	struct sk_buff *skb_deliver;
+	enum hsr_dev_idx dev_in_idx, dev_other_idx;
+	bool dup_out;
+	int ret;
+
+	if (eth_hdr(skb)->h_proto != htons(ETH_P_PRP))
+		return RX_HANDLER_PASS;
+
+	hsr = get_hsr_master(dev);
+	if (!hsr) {
+		WARN_ON_ONCE(1);
+		return RX_HANDLER_PASS;
+	}
+
+	if (dev == hsr->slave[0]) {
+		dev_in_idx = HSR_DEV_SLAVE_A;
+		dev_other_idx = HSR_DEV_SLAVE_B;
+	} else {
+		dev_in_idx = HSR_DEV_SLAVE_B;
+		dev_other_idx = HSR_DEV_SLAVE_A;
+	}
+
+	node = hsr_find_node(&hsr->self_node_db, skb);
+	if (node) {
+		/* Always kill frames sent by ourselves */
+		kfree_skb(skb);
+		return RX_HANDLER_CONSUMED;
+	}
+
+	/* Is this frame a candidate for local reception? */
+	deliver_to_self = false;
+	if ((skb->pkt_type == PACKET_HOST) ||
+	    (skb->pkt_type == PACKET_MULTICAST) ||
+	    (skb->pkt_type == PACKET_BROADCAST))
+		deliver_to_self = true;
+	else if (ether_addr_equal(eth_hdr(skb)->h_dest, hsr->dev->dev_addr)) {
+		skb->pkt_type = PACKET_HOST;
+		deliver_to_self = true;
+	}
+
+
+	rcu_read_lock(); /* node_db */
+	node = hsr_find_node(&hsr->node_db, skb);
+
+	if (is_supervision_frame(hsr, skb)) {
+		skb_pull(skb, sizeof(struct hsr_sup_tag));
+		node = hsr_merge_node(hsr, node, skb, dev_in_idx);
+		if (!node) {
+			rcu_read_unlock(); /* node_db */
+			kfree_skb(skb);
+			hsr->dev->stats.rx_dropped++;
+			return RX_HANDLER_CONSUMED;
+		}
+		skb_push(skb, sizeof(struct hsr_sup_tag));
+		deliver_to_self = false;
+	}
+
+	if (!node) {
+		/* Source node unknown; this might be a HSR frame from
+		 * another net (different multicast address). Ignore it.
+		 */
+		rcu_read_unlock(); /* node_db */
+		kfree_skb(skb);
+		return RX_HANDLER_CONSUMED;
+	}
+
+	/* Register ALL incoming frames as outgoing through the other interface.
+	 * This allows us to register frames as incoming only if they are valid
+	 * for the receiving interface, without using a specific counter for
+	 * incoming frames.
+	 */
+	dup_out = hsr_register_frame_out(node, dev_other_idx, skb);
+	if (!dup_out)
+		hsr_register_frame_in(node, dev_in_idx);
+
+	/* Forward this frame? */
+	if (!dup_out && (skb->pkt_type != PACKET_HOST))
+		other_slave = get_other_slave(hsr, dev);
+	else
+		other_slave = NULL;
+
+	if (hsr_register_frame_out(node, HSR_DEV_MASTER, skb))
+		deliver_to_self = false;
+
+	rcu_read_unlock(); /* node_db */
+
+	if (!deliver_to_self && !other_slave) {
+		kfree_skb(skb);
+		/* Circulated frame; silently remove it. */
+		return RX_HANDLER_CONSUMED;
+	}
+
+	skb_deliver = skb;
+	if (deliver_to_self && other_slave) {
+		/* skb_clone() is not enough since we will strip the hsr tag
+		 * and do address substitution below
+		 */
+		skb_deliver = pskb_copy(skb, GFP_ATOMIC);
+		if (!skb_deliver) {
+			deliver_to_self = false;
+			hsr->dev->stats.rx_dropped++;
+		}
+	}
+
+	if (deliver_to_self) {
+		bool multicast_frame;
+
+		skb_deliver = hsr_pull_tag(skb_deliver);
+		if (!skb_deliver) {
+			hsr->dev->stats.rx_dropped++;
+			goto forward;
+		}
+#if !defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
+		/* Move everything in the header that is after the HSR tag,
+		 * to work around alignment problems caused by the 6-byte HSR
+		 * tag. In practice, this removes/overwrites the HSR tag in
+		 * the header and restores a "standard" packet.
+		 */
+		memmove(skb_deliver->data - HSR_HLEN, skb_deliver->data,
+			skb_headlen(skb_deliver));
+
+		/* Adjust skb members so they correspond with the move above.
+		 * This cannot possibly underflow skb->data since hsr_pull_tag()
+		 * above succeeded.
+		 * At this point in the protocol stack, the transport and
+		 * network headers have not been set yet, and we haven't touched
+		 * the mac header nor the head. So we only need to adjust data
+		 * and tail:
+		 */
+		skb_deliver->data -= HSR_HLEN;
+		skb_deliver->tail -= HSR_HLEN;
+#endif
+		skb_deliver->dev = hsr->dev;
+		hsr_addr_subst_source(hsr, skb_deliver);
+		multicast_frame = (skb_deliver->pkt_type == PACKET_MULTICAST);
+		ret = netif_rx(skb_deliver);
+		if (ret == NET_RX_DROP) {
+			hsr->dev->stats.rx_dropped++;
+		} else {
+			hsr->dev->stats.rx_packets++;
+			hsr->dev->stats.rx_bytes += skb->len;
+			if (multicast_frame)
+				hsr->dev->stats.multicast++;
+		}
+	}
+
+forward:
+	if (other_slave) {
+		skb_push(skb, ETH_HLEN);
+		skb->dev = other_slave;
+		dev_queue_xmit(skb);
+	}
+
+	return RX_HANDLER_CONSUMED;
+}