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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /net/hsr/hsr_forward.c
Initial import
Diffstat (limited to 'net/hsr/hsr_forward.c')
-rw-r--r--net/hsr/hsr_forward.c368
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 000000000..7871ed6d3
--- /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);
+}