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;
+}