net/ncsi: NCSI command packet handler

The NCSI command packets are sent from MC (Management Controller)
to remote end. They are used for multiple purposes: probe existing
NCSI package/channel, retrieve NCSI channel's capability, configure
NCSI channel etc.

This defines struct to represent NCSI command packets and introduces
function ncsi_xmit_cmd(), which will be used to transmit NCSI command
packet according to the request. The request is represented by struct
ncsi_cmd_arg.

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, 367 insertions, 0 deletions

diff --git a/net/ncsi/ncsi-cmd.c b/net/ncsi/ncsi-cmd.c
new file mode 100644
index 000000000000..21057a8ceeac
--- /dev/null
+++ b/net/ncsi/ncsi-cmd.c
@@ -0,0 +1,367 @@
+/*
+ * 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/etherdevice.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"
+
+u32 ncsi_calculate_checksum(unsigned char *data, int len)
+{
+	u32 checksum = 0;
+	int i;
+
+	for (i = 0; i < len; i += 2)
+		checksum += (((u32)data[i] << 8) | data[i + 1]);
+
+	checksum = (~checksum + 1);
+	return checksum;
+}
+
+/* This function should be called after the data area has been
+ * populated completely.
+ */
+static void ncsi_cmd_build_header(struct ncsi_pkt_hdr *h,
+				  struct ncsi_cmd_arg *nca)
+{
+	u32 checksum;
+	__be32 *pchecksum;
+
+	h->mc_id        = 0;
+	h->revision     = NCSI_PKT_REVISION;
+	h->reserved     = 0;
+	h->id           = nca->id;
+	h->type         = nca->type;
+	h->channel      = NCSI_TO_CHANNEL(nca->package,
+					  nca->channel);
+	h->length       = htons(nca->payload);
+	h->reserved1[0] = 0;
+	h->reserved1[1] = 0;
+
+	/* Fill with calculated checksum */
+	checksum = ncsi_calculate_checksum((unsigned char *)h,
+					   sizeof(*h) + nca->payload);
+	pchecksum = (__be32 *)((void *)h + sizeof(struct ncsi_pkt_hdr) +
+		    nca->payload);
+	*pchecksum = htonl(checksum);
+}
+
+static int ncsi_cmd_handler_default(struct sk_buff *skb,
+				    struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_cmd_pkt *cmd;
+
+	cmd = (struct ncsi_cmd_pkt *)skb_put(skb, sizeof(*cmd));
+	memset(cmd, 0, sizeof(*cmd));
+	ncsi_cmd_build_header(&cmd->cmd.common, nca);
+
+	return 0;
+}
+
+static int ncsi_cmd_handler_sp(struct sk_buff *skb,
+			       struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_cmd_sp_pkt *cmd;
+
+	cmd = (struct ncsi_cmd_sp_pkt *)skb_put(skb, sizeof(*cmd));
+	memset(cmd, 0, sizeof(*cmd));
+	cmd->hw_arbitration = nca->bytes[0];
+	ncsi_cmd_build_header(&cmd->cmd.common, nca);
+
+	return 0;
+}
+
+static int ncsi_cmd_handler_dc(struct sk_buff *skb,
+			       struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_cmd_dc_pkt *cmd;
+
+	cmd = (struct ncsi_cmd_dc_pkt *)skb_put(skb, sizeof(*cmd));
+	memset(cmd, 0, sizeof(*cmd));
+	cmd->ald = nca->bytes[0];
+	ncsi_cmd_build_header(&cmd->cmd.common, nca);
+
+	return 0;
+}
+
+static int ncsi_cmd_handler_rc(struct sk_buff *skb,
+			       struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_cmd_rc_pkt *cmd;
+
+	cmd = (struct ncsi_cmd_rc_pkt *)skb_put(skb, sizeof(*cmd));
+	memset(cmd, 0, sizeof(*cmd));
+	ncsi_cmd_build_header(&cmd->cmd.common, nca);
+
+	return 0;
+}
+
+static int ncsi_cmd_handler_ae(struct sk_buff *skb,
+			       struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_cmd_ae_pkt *cmd;
+
+	cmd = (struct ncsi_cmd_ae_pkt *)skb_put(skb, sizeof(*cmd));
+	memset(cmd, 0, sizeof(*cmd));
+	cmd->mc_id = nca->bytes[0];
+	cmd->mode = htonl(nca->dwords[1]);
+	ncsi_cmd_build_header(&cmd->cmd.common, nca);
+
+	return 0;
+}
+
+static int ncsi_cmd_handler_sl(struct sk_buff *skb,
+			       struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_cmd_sl_pkt *cmd;
+
+	cmd = (struct ncsi_cmd_sl_pkt *)skb_put(skb, sizeof(*cmd));
+	memset(cmd, 0, sizeof(*cmd));
+	cmd->mode = htonl(nca->dwords[0]);
+	cmd->oem_mode = htonl(nca->dwords[1]);
+	ncsi_cmd_build_header(&cmd->cmd.common, nca);
+
+	return 0;
+}
+
+static int ncsi_cmd_handler_svf(struct sk_buff *skb,
+				struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_cmd_svf_pkt *cmd;
+
+	cmd = (struct ncsi_cmd_svf_pkt *)skb_put(skb, sizeof(*cmd));
+	memset(cmd, 0, sizeof(*cmd));
+	cmd->vlan = htons(nca->words[0]);
+	cmd->index = nca->bytes[2];
+	cmd->enable = nca->bytes[3];
+	ncsi_cmd_build_header(&cmd->cmd.common, nca);
+
+	return 0;
+}
+
+static int ncsi_cmd_handler_ev(struct sk_buff *skb,
+			       struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_cmd_ev_pkt *cmd;
+
+	cmd = (struct ncsi_cmd_ev_pkt *)skb_put(skb, sizeof(*cmd));
+	memset(cmd, 0, sizeof(*cmd));
+	cmd->mode = nca->bytes[0];
+	ncsi_cmd_build_header(&cmd->cmd.common, nca);
+
+	return 0;
+}
+
+static int ncsi_cmd_handler_sma(struct sk_buff *skb,
+				struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_cmd_sma_pkt *cmd;
+	int i;
+
+	cmd = (struct ncsi_cmd_sma_pkt *)skb_put(skb, sizeof(*cmd));
+	memset(cmd, 0, sizeof(*cmd));
+	for (i = 0; i < 6; i++)
+		cmd->mac[i] = nca->bytes[i];
+	cmd->index = nca->bytes[6];
+	cmd->at_e = nca->bytes[7];
+	ncsi_cmd_build_header(&cmd->cmd.common, nca);
+
+	return 0;
+}
+
+static int ncsi_cmd_handler_ebf(struct sk_buff *skb,
+				struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_cmd_ebf_pkt *cmd;
+
+	cmd = (struct ncsi_cmd_ebf_pkt *)skb_put(skb, sizeof(*cmd));
+	memset(cmd, 0, sizeof(*cmd));
+	cmd->mode = htonl(nca->dwords[0]);
+	ncsi_cmd_build_header(&cmd->cmd.common, nca);
+
+	return 0;
+}
+
+static int ncsi_cmd_handler_egmf(struct sk_buff *skb,
+				 struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_cmd_egmf_pkt *cmd;
+
+	cmd = (struct ncsi_cmd_egmf_pkt *)skb_put(skb, sizeof(*cmd));
+	memset(cmd, 0, sizeof(*cmd));
+	cmd->mode = htonl(nca->dwords[0]);
+	ncsi_cmd_build_header(&cmd->cmd.common, nca);
+
+	return 0;
+}
+
+static int ncsi_cmd_handler_snfc(struct sk_buff *skb,
+				 struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_cmd_snfc_pkt *cmd;
+
+	cmd = (struct ncsi_cmd_snfc_pkt *)skb_put(skb, sizeof(*cmd));
+	memset(cmd, 0, sizeof(*cmd));
+	cmd->mode = nca->bytes[0];
+	ncsi_cmd_build_header(&cmd->cmd.common, nca);
+
+	return 0;
+}
+
+static struct ncsi_cmd_handler {
+	unsigned char type;
+	int           payload;
+	int           (*handler)(struct sk_buff *skb,
+				 struct ncsi_cmd_arg *nca);
+} ncsi_cmd_handlers[] = {
+	{ NCSI_PKT_CMD_CIS,    0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_SP,     4, ncsi_cmd_handler_sp      },
+	{ NCSI_PKT_CMD_DP,     0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_EC,     0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_DC,     4, ncsi_cmd_handler_dc      },
+	{ NCSI_PKT_CMD_RC,     4, ncsi_cmd_handler_rc      },
+	{ NCSI_PKT_CMD_ECNT,   0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_DCNT,   0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_AE,     8, ncsi_cmd_handler_ae      },
+	{ NCSI_PKT_CMD_SL,     8, ncsi_cmd_handler_sl      },
+	{ NCSI_PKT_CMD_GLS,    0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_SVF,    4, ncsi_cmd_handler_svf     },
+	{ NCSI_PKT_CMD_EV,     4, ncsi_cmd_handler_ev      },
+	{ NCSI_PKT_CMD_DV,     0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_SMA,    8, ncsi_cmd_handler_sma     },
+	{ NCSI_PKT_CMD_EBF,    4, ncsi_cmd_handler_ebf     },
+	{ NCSI_PKT_CMD_DBF,    0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_EGMF,   4, ncsi_cmd_handler_egmf    },
+	{ NCSI_PKT_CMD_DGMF,   0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_SNFC,   4, ncsi_cmd_handler_snfc    },
+	{ NCSI_PKT_CMD_GVI,    0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_GC,     0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_GP,     0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_GCPS,   0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_GNS,    0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_GNPTS,  0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_GPS,    0, ncsi_cmd_handler_default },
+	{ NCSI_PKT_CMD_OEM,    0, NULL                     },
+	{ NCSI_PKT_CMD_PLDM,   0, NULL                     },
+	{ NCSI_PKT_CMD_GPUUID, 0, ncsi_cmd_handler_default }
+};
+
+static struct ncsi_request *ncsi_alloc_command(struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_dev_priv *ndp = nca->ndp;
+	struct ncsi_dev *nd = &ndp->ndev;
+	struct net_device *dev = nd->dev;
+	int hlen = LL_RESERVED_SPACE(dev);
+	int tlen = dev->needed_tailroom;
+	int len = hlen + tlen;
+	struct sk_buff *skb;
+	struct ncsi_request *nr;
+
+	nr = ncsi_alloc_request(ndp, nca->driven);
+	if (!nr)
+		return NULL;
+
+	/* NCSI command packet has 16-bytes header, payload, 4 bytes checksum.
+	 * The packet needs padding if its payload is less than 26 bytes to
+	 * meet 64 bytes minimal ethernet frame length.
+	 */
+	len += sizeof(struct ncsi_cmd_pkt_hdr) + 4;
+	if (nca->payload < 26)
+		len += 26;
+	else
+		len += nca->payload;
+
+	/* Allocate skb */
+	skb = alloc_skb(len, GFP_ATOMIC);
+	if (!skb) {
+		ncsi_free_request(nr);
+		return NULL;
+	}
+
+	nr->cmd = skb;
+	skb_reserve(skb, hlen);
+	skb_reset_network_header(skb);
+
+	skb->dev = dev;
+	skb->protocol = htons(ETH_P_NCSI);
+
+	return nr;
+}
+
+int ncsi_xmit_cmd(struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_request *nr;
+	struct ethhdr *eh;
+	struct ncsi_cmd_handler *nch = NULL;
+	int i, ret;
+
+	/* Search for the handler */
+	for (i = 0; i < ARRAY_SIZE(ncsi_cmd_handlers); i++) {
+		if (ncsi_cmd_handlers[i].type == nca->type) {
+			if (ncsi_cmd_handlers[i].handler)
+				nch = &ncsi_cmd_handlers[i];
+			else
+				nch = NULL;
+
+			break;
+		}
+	}
+
+	if (!nch) {
+		netdev_err(nca->ndp->ndev.dev,
+			   "Cannot send packet with type 0x%02x\n", nca->type);
+		return -ENOENT;
+	}
+
+	/* Get packet payload length and allocate the request */
+	nca->payload = nch->payload;
+	nr = ncsi_alloc_command(nca);
+	if (!nr)
+		return -ENOMEM;
+
+	/* Prepare the packet */
+	nca->id = nr->id;
+	ret = nch->handler(nr->cmd, nca);
+	if (ret) {
+		ncsi_free_request(nr);
+		return ret;
+	}
+
+	/* Fill the ethernet header */
+	eh = (struct ethhdr *)skb_push(nr->cmd, sizeof(*eh));
+	eh->h_proto = htons(ETH_P_NCSI);
+	eth_broadcast_addr(eh->h_dest);
+	eth_broadcast_addr(eh->h_source);
+
+	/* Start the timer for the request that might not have
+	 * corresponding response. Given NCSI is an internal
+	 * connection a 1 second delay should be sufficient.
+	 */
+	nr->enabled = true;
+	mod_timer(&nr->timer, jiffies + 1 * HZ);
+
+	/* Send NCSI packet */
+	skb_get(nr->cmd);
+	ret = dev_queue_xmit(nr->cmd);
+	if (ret < 0) {
+		ncsi_free_request(nr);
+		return ret;
+	}
+
+	return 0;
+}