linux/net/hsr/hsr_slave.c

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/* 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 <linux/if_arp.h>
#include "hsr_main.h"
#include "hsr_device.h"
#include "hsr_framereg.h"
static int hsr_check_dev_ok(struct net_device *dev)
{
/* Don't allow HSR on non-ethernet like devices */
if ((dev->flags & IFF_LOOPBACK) || (dev->type != ARPHRD_ETHER) ||
(dev->addr_len != ETH_ALEN)) {
netdev_info(dev, "Cannot use loopback or non-ethernet device as HSR slave.\n");
return -EINVAL;
}
/* Don't allow enslaving hsr devices */
if (is_hsr_master(dev)) {
netdev_info(dev, "Cannot create trees of HSR devices.\n");
return -EINVAL;
}
if (hsr_port_exists(dev)) {
netdev_info(dev, "This device is already a HSR slave.\n");
return -EINVAL;
}
if (dev->priv_flags & IFF_802_1Q_VLAN) {
netdev_info(dev, "HSR on top of VLAN is not yet supported in this driver.\n");
return -EINVAL;
}
/* HSR over bonded devices has not been tested, but I'm not sure it
* won't work...
*/
return 0;
}
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 hsr_port *port, *other_port, *master;
struct hsr_priv *hsr;
struct hsr_node *node;
bool deliver_to_self;
struct sk_buff *skb_deliver;
bool dup_out;
int ret;
if (eth_hdr(skb)->h_proto != htons(ETH_P_PRP))
return RX_HANDLER_PASS;
rcu_read_lock(); /* ports & node */
port = hsr_port_get_rcu(skb->dev);
hsr = port->hsr;
master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
node = hsr_find_node(&hsr->self_node_db, skb);
if (node) {
/* Always kill frames sent by ourselves */
kfree_skb(skb);
ret = RX_HANDLER_CONSUMED;
goto finish;
}
/* 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,
master->dev->dev_addr)) {
skb->pkt_type = PACKET_HOST;
deliver_to_self = true;
}
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(node, skb, port);
if (!node) {
kfree_skb(skb);
master->dev->stats.rx_dropped++;
ret = RX_HANDLER_CONSUMED;
goto finish;
}
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.
*/
kfree_skb(skb);
ret = RX_HANDLER_CONSUMED;
goto finish;
}
if (port->type == HSR_PT_SLAVE_A)
other_port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
else
other_port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
/* 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.
*/
if (other_port)
dup_out = hsr_register_frame_out(node, other_port, skb);
else
dup_out = 0;
if (!dup_out)
hsr_register_frame_in(node, port);
/* Forward this frame? */
if (dup_out || (skb->pkt_type == PACKET_HOST))
other_port = NULL;
if (hsr_register_frame_out(node, master, skb))
deliver_to_self = false;
if (!deliver_to_self && !other_port) {
kfree_skb(skb);
/* Circulated frame; silently remove it. */
ret = RX_HANDLER_CONSUMED;
goto finish;
}
skb_deliver = skb;
if (deliver_to_self && other_port) {
/* 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;
master->dev->stats.rx_dropped++;
}
}
if (deliver_to_self) {
bool multicast_frame;
skb_deliver = hsr_pull_tag(skb_deliver);
if (!skb_deliver) {
master->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 = master->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) {
master->dev->stats.rx_dropped++;
} else {
master->dev->stats.rx_packets++;
master->dev->stats.rx_bytes += skb->len;
if (multicast_frame)
master->dev->stats.multicast++;
}
}
forward:
if (other_port) {
skb_push(skb, ETH_HLEN);
skb->dev = other_port->dev;
dev_queue_xmit(skb);
}
ret = RX_HANDLER_CONSUMED;
finish:
rcu_read_unlock();
return ret;
}
/* Setup device to be added to the HSR bridge. */
static int hsr_portdev_setup(struct net_device *dev, struct hsr_port *port)
{
int res;
dev_hold(dev);
res = dev_set_promiscuity(dev, 1);
if (res)
goto fail_promiscuity;
res = netdev_rx_handler_register(dev, hsr_handle_frame, port);
if (res)
goto fail_rx_handler;
dev_disable_lro(dev);
/* FIXME:
* What does net device "adjacency" mean? Should we do
* res = netdev_master_upper_dev_link(port->dev, port->hsr->dev); ?
*/
return 0;
fail_rx_handler:
dev_set_promiscuity(dev, -1);
fail_promiscuity:
dev_put(dev);
return res;
}
int hsr_add_port(struct hsr_priv *hsr, struct net_device *dev,
enum hsr_port_type type)
{
struct hsr_port *port, *master;
int res;
if (type != HSR_PT_MASTER) {
res = hsr_check_dev_ok(dev);
if (res)
return res;
}
port = hsr_port_get_hsr(hsr, type);
if (port != NULL)
return -EBUSY; /* This port already exists */
port = kzalloc(sizeof(*port), GFP_KERNEL);
if (port == NULL)
return -ENOMEM;
if (type != HSR_PT_MASTER) {
res = hsr_portdev_setup(dev, port);
if (res)
goto fail_dev_setup;
}
port->hsr = hsr;
port->dev = dev;
port->type = type;
list_add_tail_rcu(&port->port_list, &hsr->ports);
synchronize_rcu();
master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
/* Set required header length */
if (dev->hard_header_len + HSR_HLEN > master->dev->hard_header_len)
master->dev->hard_header_len = dev->hard_header_len + HSR_HLEN;
dev_set_mtu(master->dev, hsr_get_max_mtu(hsr));
return 0;
fail_dev_setup:
kfree(port);
return res;
}
void hsr_del_port(struct hsr_port *port)
{
struct hsr_priv *hsr;
struct hsr_port *master;
hsr = port->hsr;
master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
list_del_rcu(&port->port_list);
if (port != master) {
dev_set_mtu(master->dev, hsr_get_max_mtu(hsr));
netdev_rx_handler_unregister(port->dev);
dev_set_promiscuity(port->dev, -1);
}
/* FIXME?
* netdev_upper_dev_unlink(port->dev, port->hsr->dev);
*/
synchronize_rcu();
dev_put(port->dev);
}