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>

net/ncsi/Makefile

 #
 # Makefile for NCSI API
 #
-obj-$(CONFIG_NET_NCSI) += ncsi-cmd.o ncsi-rsp.o ncsi-manage.o
+obj-$(CONFIG_NET_NCSI) += ncsi-cmd.o ncsi-rsp.o ncsi-aen.o ncsi-manage.o

net/ncsi/internal.h

@@ -323,5 +323,6 @@ u32 ncsi_calculate_checksum(unsigned char *data, int len);
 int ncsi_xmit_cmd(struct ncsi_cmd_arg *nca);
 int ncsi_rcv_rsp(struct sk_buff *skb, struct net_device *dev,
 		 struct packet_type *pt, struct net_device *orig_dev);
+int ncsi_aen_handler(struct ncsi_dev_priv *ndp, struct sk_buff *skb);
 
 #endif /* __NCSI_INTERNAL_H__ */

net/ncsi/ncsi-aen.c

+/*
+ * 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;
+}

net/ncsi/ncsi-pkt.h

@@ -31,6 +31,12 @@ struct ncsi_rsp_pkt_hdr {
 	__be16              reason; /* Response reason           */
 };
 
+struct ncsi_aen_pkt_hdr {
+	struct ncsi_pkt_hdr common;       /* Common NCSI packet header */
+	unsigned char       reserved2[3]; /* Reserved                  */
+	unsigned char       type;         /* AEN packet type           */
+};
+
 /* NCSI common command packet */
 struct ncsi_cmd_pkt {
 	struct ncsi_cmd_pkt_hdr cmd;      /* Command header */
@@ -296,6 +302,30 @@ struct ncsi_rsp_gpuuid_pkt {
 	__be32                  checksum;
 };
 
+/* AEN: Link State Change */
+struct ncsi_aen_lsc_pkt {
+	struct ncsi_aen_pkt_hdr aen;        /* AEN header      */
+	__be32                  status;     /* Link status     */
+	__be32                  oem_status; /* OEM link status */
+	__be32                  checksum;   /* Checksum        */
+	unsigned char           pad[14];
+};
+
+/* AEN: Configuration Required */
+struct ncsi_aen_cr_pkt {
+	struct ncsi_aen_pkt_hdr aen;      /* AEN header */
+	__be32                  checksum; /* Checksum   */
+	unsigned char           pad[22];
+};
+
+/* AEN: Host Network Controller Driver Status Change */
+struct ncsi_aen_hncdsc_pkt {
+	struct ncsi_aen_pkt_hdr aen;      /* AEN header */
+	__be32                  status;   /* Status     */
+	__be32                  checksum; /* Checksum   */
+	unsigned char           pad[18];
+};
+
 /* NCSI packet revision */
 #define NCSI_PKT_REVISION	0x01
 
@@ -376,4 +406,10 @@ struct ncsi_rsp_gpuuid_pkt {
 #define NCSI_PKT_RSP_R_LENGTH		0x0005 /* Invalid payload length   */
 #define NCSI_PKT_RSP_R_UNKNOWN		0x7fff /* Command type unsupported */
 
+/* NCSI AEN packet type */
+#define NCSI_PKT_AEN		0xFF /* AEN Packet               */
+#define NCSI_PKT_AEN_LSC	0x00 /* Link status change       */
+#define NCSI_PKT_AEN_CR		0x01 /* Configuration required   */
+#define NCSI_PKT_AEN_HNCDSC	0x02 /* HNC driver status change */
+
 #endif /* __NCSI_PKT_H__ */

net/ncsi/ncsi-rsp.c

@@ -980,8 +980,12 @@ int ncsi_rcv_rsp(struct sk_buff *skb, struct net_device *dev,
 	if (!ndp)
 		return -ENODEV;
 
-	/* Find the handler */
+	/* Check if it is AEN packet */
 	hdr = (struct ncsi_pkt_hdr *)skb_network_header(skb);
+	if (hdr->type == NCSI_PKT_AEN)
+		return ncsi_aen_handler(ndp, skb);
+
+	/* Find the handler */
 	for (i = 0; i < ARRAY_SIZE(ncsi_rsp_handlers); i++) {
 		if (ncsi_rsp_handlers[i].type == hdr->type) {
 			if (ncsi_rsp_handlers[i].handler)