1 files changed, 368 insertions, 0 deletions

diff --git a/net/hsr/hsr_forward.c b/net/hsr/hsr_forward.c
new file mode 100644
index 000000000000..7871ed6d3825
--- /dev/null
+++ b/net/hsr/hsr_forward.c
@@ -0,0 +1,368 @@
+/* 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_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;
+
+	WARN_ON_ONCE(!skb_mac_header_was_set(skb));
+	hdr = (struct hsr_ethhdr_sp *) skb_mac_header(skb);
+
+	if (!ether_addr_equal(hdr->ethhdr.h_dest,
+			      hsr->sup_multicast_addr))
+		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;
+
+	skb_reset_mac_header(skb);
+
+	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;
+	else
+		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;
+	skb_reset_mac_header(skb);
+
+	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);
+	skb_reset_mac_header(skb);
+
+	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) {
+		dev->stats.rx_dropped++;
+	} else {
+		dev->stats.rx_packets++;
+		dev->stats.rx_bytes += skb->len;
+		if (was_multicast_frame)
+			dev->stats.multicast++;
+	}
+}
+
+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)
+			continue;
+
+		/* Don't deliver locally unless we should */
+		if ((port->type == HSR_PT_MASTER) && !frame->is_local_dest)
+			continue;
+
+		/* Deliver frames directly addressed to us to master only */
+		if ((port->type != HSR_PT_MASTER) && frame->is_local_exclusive)
+			continue;
+
+		/* Don't send frame over port where it has been sent before */
+		if (hsr_register_frame_out(port, frame->node_src,
+					   frame->sequence_nr))
+			continue;
+
+		if (frame->is_supervision && (port->type == HSR_PT_MASTER)) {
+			hsr_handle_sup_frame(frame->skb_hsr,
+					     frame->node_src,
+					     frame->port_rcv);
+			continue;
+		}
+
+		if (port->type != HSR_PT_MASTER)
+			skb = frame_get_tagged_skb(frame, port);
+		else
+			skb = frame_get_stripped_skb(frame, port);
+		if (skb == NULL) {
+			/* FIXME: Record the dropped frame? */
+			continue;
+		}
+
+		skb->dev = port->dev;
+		if (port->type == HSR_PT_MASTER)
+			hsr_deliver_master(skb, port->dev, frame->node_src);
+		else
+			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,
+				       frame->is_supervision);
+	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;
+		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);
+	hsr_forward_do(&frame);
+
+	if (frame.skb_hsr != NULL)
+		kfree_skb(frame.skb_hsr);
+	if (frame.skb_std != NULL)
+		kfree_skb(frame.skb_std);
+	return;
+
+out_drop:
+	port->dev->stats.tx_dropped++;
+	kfree_skb(skb);
+}