From 81ba6afd6e6443d2bf4bf40f16df1f1f91c603f8 Mon Sep 17 00:00:00 2001 From: Arvid Brodin Date: Fri, 4 Jul 2014 23:35:24 +0200 Subject: 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 Signed-off-by: David S. Miller --- net/hsr/hsr_slave.c | 243 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 243 insertions(+) create mode 100644 net/hsr/hsr_slave.c (limited to 'net/hsr/hsr_slave.c') 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 +#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; +} -- cgit v1.2.3-59-g8ed1b