net/ncsi: NCSI AEN packet handler

This introduces NCSI AEN packet handlers that result in (A) the
currently active channel is reconfigured; (B) Currently active
channel is deconfigured and disabled, another channel is chosen
as active one and configured. Case (B) won't happen if hardware
arbitration has been enabled, the channel that was in active
state is suspended simply.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 193 insertions, 0 deletions

diff --git a/net/ncsi/ncsi-aen.c b/net/ncsi/ncsi-aen.c
new file mode 100644
index 0000000..d463468
--- /dev/null
+++ b/net/ncsi/ncsi-aen.c
@@ -0,0 +1,193 @@
+/*
+ * Copyright Gavin Shan, IBM Corporation 2016.
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+
+#include <net/ncsi.h>
+#include <net/net_namespace.h>
+#include <net/sock.h>
+
+#include "internal.h"
+#include "ncsi-pkt.h"
+
+static int ncsi_validate_aen_pkt(struct ncsi_aen_pkt_hdr *h,
+				 const unsigned short payload)
+{
+	u32 checksum;
+	__be32 *pchecksum;
+
+	if (h->common.revision != NCSI_PKT_REVISION)
+		return -EINVAL;
+	if (ntohs(h->common.length) != payload)
+		return -EINVAL;
+
+	/* Validate checksum, which might be zeroes if the
+	 * sender doesn't support checksum according to NCSI
+	 * specification.
+	 */
+	pchecksum = (__be32 *)((void *)(h + 1) + payload - 4);
+	if (ntohl(*pchecksum) == 0)
+		return 0;
+
+	checksum = ncsi_calculate_checksum((unsigned char *)h,
+					   sizeof(*h) + payload - 4);
+	if (*pchecksum != htonl(checksum))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int ncsi_aen_handler_lsc(struct ncsi_dev_priv *ndp,
+				struct ncsi_aen_pkt_hdr *h)
+{
+	struct ncsi_aen_lsc_pkt *lsc;
+	struct ncsi_channel *nc;
+	struct ncsi_channel_mode *ncm;
+	unsigned long old_data;
+	unsigned long flags;
+
+	/* Find the NCSI channel */
+	ncsi_find_package_and_channel(ndp, h->common.channel, NULL, &nc);
+	if (!nc)
+		return -ENODEV;
+
+	/* Update the link status */
+	ncm = &nc->modes[NCSI_MODE_LINK];
+	lsc = (struct ncsi_aen_lsc_pkt *)h;
+	old_data = ncm->data[2];
+	ncm->data[2] = ntohl(lsc->status);
+	ncm->data[4] = ntohl(lsc->oem_status);
+	if (!((old_data ^ ncm->data[2]) & 0x1) ||
+	    !list_empty(&nc->link))
+		return 0;
+	if (!(nc->state == NCSI_CHANNEL_INACTIVE && (ncm->data[2] & 0x1)) &&
+	    !(nc->state == NCSI_CHANNEL_ACTIVE && !(ncm->data[2] & 0x1)))
+		return 0;
+
+	if (!(ndp->flags & NCSI_DEV_HWA) &&
+	    nc->state == NCSI_CHANNEL_ACTIVE)
+		ndp->flags |= NCSI_DEV_RESHUFFLE;
+
+	ncsi_stop_channel_monitor(nc);
+	spin_lock_irqsave(&ndp->lock, flags);
+	list_add_tail_rcu(&nc->link, &ndp->channel_queue);
+	spin_unlock_irqrestore(&ndp->lock, flags);
+
+	return ncsi_process_next_channel(ndp);
+}
+
+static int ncsi_aen_handler_cr(struct ncsi_dev_priv *ndp,
+			       struct ncsi_aen_pkt_hdr *h)
+{
+	struct ncsi_channel *nc;
+	unsigned long flags;
+
+	/* Find the NCSI channel */
+	ncsi_find_package_and_channel(ndp, h->common.channel, NULL, &nc);
+	if (!nc)
+		return -ENODEV;
+
+	if (!list_empty(&nc->link) ||
+	    nc->state != NCSI_CHANNEL_ACTIVE)
+		return 0;
+
+	ncsi_stop_channel_monitor(nc);
+	spin_lock_irqsave(&ndp->lock, flags);
+	xchg(&nc->state, NCSI_CHANNEL_INACTIVE);
+	list_add_tail_rcu(&nc->link, &ndp->channel_queue);
+	spin_unlock_irqrestore(&ndp->lock, flags);
+
+	return ncsi_process_next_channel(ndp);
+}
+
+static int ncsi_aen_handler_hncdsc(struct ncsi_dev_priv *ndp,
+				   struct ncsi_aen_pkt_hdr *h)
+{
+	struct ncsi_channel *nc;
+	struct ncsi_channel_mode *ncm;
+	struct ncsi_aen_hncdsc_pkt *hncdsc;
+	unsigned long flags;
+
+	/* Find the NCSI channel */
+	ncsi_find_package_and_channel(ndp, h->common.channel, NULL, &nc);
+	if (!nc)
+		return -ENODEV;
+
+	/* If the channel is active one, we need reconfigure it */
+	ncm = &nc->modes[NCSI_MODE_LINK];
+	hncdsc = (struct ncsi_aen_hncdsc_pkt *)h;
+	ncm->data[3] = ntohl(hncdsc->status);
+	if (!list_empty(&nc->link) ||
+	    nc->state != NCSI_CHANNEL_ACTIVE ||
+	    (ncm->data[3] & 0x1))
+		return 0;
+
+	if (ndp->flags & NCSI_DEV_HWA)
+		ndp->flags |= NCSI_DEV_RESHUFFLE;
+
+	/* If this channel is the active one and the link doesn't
+	 * work, we have to choose another channel to be active one.
+	 * The logic here is exactly similar to what we do when link
+	 * is down on the active channel.
+	 */
+	ncsi_stop_channel_monitor(nc);
+	spin_lock_irqsave(&ndp->lock, flags);
+	list_add_tail_rcu(&nc->link, &ndp->channel_queue);
+	spin_unlock_irqrestore(&ndp->lock, flags);
+
+	ncsi_process_next_channel(ndp);
+
+	return 0;
+}
+
+static struct ncsi_aen_handler {
+	unsigned char type;
+	int           payload;
+	int           (*handler)(struct ncsi_dev_priv *ndp,
+				 struct ncsi_aen_pkt_hdr *h);
+} ncsi_aen_handlers[] = {
+	{ NCSI_PKT_AEN_LSC,    12, ncsi_aen_handler_lsc    },
+	{ NCSI_PKT_AEN_CR,      4, ncsi_aen_handler_cr     },
+	{ NCSI_PKT_AEN_HNCDSC,  4, ncsi_aen_handler_hncdsc }
+};
+
+int ncsi_aen_handler(struct ncsi_dev_priv *ndp, struct sk_buff *skb)
+{
+	struct ncsi_aen_pkt_hdr *h;
+	struct ncsi_aen_handler *nah = NULL;
+	int i, ret;
+
+	/* Find the handler */
+	h = (struct ncsi_aen_pkt_hdr *)skb_network_header(skb);
+	for (i = 0; i < ARRAY_SIZE(ncsi_aen_handlers); i++) {
+		if (ncsi_aen_handlers[i].type == h->type) {
+			nah = &ncsi_aen_handlers[i];
+			break;
+		}
+	}
+
+	if (!nah) {
+		netdev_warn(ndp->ndev.dev, "Invalid AEN (0x%x) received\n",
+			    h->type);
+		return -ENOENT;
+	}
+
+	ret = ncsi_validate_aen_pkt(h, nah->payload);
+	if (ret)
+		goto out;
+
+	ret = nah->handler(ndp, h);
+out:
+	consume_skb(skb);
+	return ret;
+}