Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 407 insertions, 0 deletions

diff --git a/net/ncsi/ncsi-cmd.c b/net/ncsi/ncsi-cmd.c
new file mode 100644
index 000000000..fd2236ee9
--- /dev/null
+++ b/net/ncsi/ncsi-cmd.c
@@ -0,0 +1,407 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright Gavin Shan, IBM Corporation 2016.
+ */
+
+#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 <net/genetlink.h>
+
+#include "internal.h"
+#include "ncsi-pkt.h"
+
+static const int padding_bytes = 26;
+
+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) +
+		    ALIGN(nca->payload, 4));
+	*pchecksum = htonl(checksum);
+}
+
+static int ncsi_cmd_handler_default(struct sk_buff *skb,
+				    struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_cmd_pkt *cmd;
+
+	cmd = skb_put_zero(skb, 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 = skb_put_zero(skb, 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 = skb_put_zero(skb, 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 = skb_put_zero(skb, 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 = skb_put_zero(skb, 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 = skb_put_zero(skb, 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 = skb_put_zero(skb, sizeof(*cmd));
+	cmd->vlan = htons(nca->words[1]);
+	cmd->index = nca->bytes[6];
+	cmd->enable = nca->bytes[7];
+	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 = skb_put_zero(skb, sizeof(*cmd));
+	cmd->mode = nca->bytes[3];
+	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 = skb_put_zero(skb, 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 = skb_put_zero(skb, 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 = skb_put_zero(skb, 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 = skb_put_zero(skb, sizeof(*cmd));
+	cmd->mode = nca->bytes[0];
+	ncsi_cmd_build_header(&cmd->cmd.common, nca);
+
+	return 0;
+}
+
+static int ncsi_cmd_handler_oem(struct sk_buff *skb,
+				struct ncsi_cmd_arg *nca)
+{
+	struct ncsi_cmd_oem_pkt *cmd;
+	unsigned int len;
+	int payload;
+	/* NC-SI spec DSP_0222_1.2.0, section 8.2.2.2
+	 * requires payload to be padded with 0 to
+	 * 32-bit boundary before the checksum field.
+	 * Ensure the padding bytes are accounted for in
+	 * skb allocation
+	 */
+
+	payload = ALIGN(nca->payload, 4);
+	len = sizeof(struct ncsi_cmd_pkt_hdr) + 4;
+	len += max(payload, padding_bytes);
+
+	cmd = skb_put_zero(skb, len);
+	unsafe_memcpy(&cmd->mfr_id, nca->data, nca->payload,
+		      /* skb allocated with enough to load the payload */);
+	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,    8, 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,   -1, ncsi_cmd_handler_oem     },
+	{ 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 payload;
+	int len = hlen + tlen;
+	struct sk_buff *skb;
+	struct ncsi_request *nr;
+
+	nr = ncsi_alloc_request(ndp, nca->req_flags);
+	if (!nr)
+		return NULL;
+
+	/* NCSI command packet has 16-bytes header, payload, 4 bytes checksum.
+	 * Payload needs padding so that the checksum field following payload is
+	 * aligned to 32-bit boundary.
+	 * 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;
+	payload = ALIGN(nca->payload, 4);
+	len += max(payload, padding_bytes);
+
+	/* 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_cmd_handler *nch = NULL;
+	struct ncsi_request *nr;
+	unsigned char type;
+	struct ethhdr *eh;
+	int i, ret;
+
+	/* Use OEM generic handler for Netlink request */
+	if (nca->req_flags == NCSI_REQ_FLAG_NETLINK_DRIVEN)
+		type = NCSI_PKT_CMD_OEM;
+	else
+		type = nca->type;
+
+	/* Search for the handler */
+	for (i = 0; i < ARRAY_SIZE(ncsi_cmd_handlers); i++) {
+		if (ncsi_cmd_handlers[i].type == 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
+	 * It is expected that if length set as negative in
+	 * handler structure means caller is initializing it
+	 * and setting length in nca before calling xmit function
+	 */
+	if (nch->payload >= 0)
+		nca->payload = nch->payload;
+	nr = ncsi_alloc_command(nca);
+	if (!nr)
+		return -ENOMEM;
+
+	/* track netlink information */
+	if (nca->req_flags == NCSI_REQ_FLAG_NETLINK_DRIVEN) {
+		nr->snd_seq = nca->info->snd_seq;
+		nr->snd_portid = nca->info->snd_portid;
+		nr->nlhdr = *nca->info->nlhdr;
+	}
+
+	/* 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 = skb_push(nr->cmd, sizeof(*eh));
+	eh->h_proto = htons(ETH_P_NCSI);
+	eth_broadcast_addr(eh->h_dest);
+
+	/* If mac address received from device then use it for
+	 * source address as unicast address else use broadcast
+	 * address as source address
+	 */
+	if (nca->ndp->gma_flag == 1)
+		memcpy(eh->h_source, nca->ndp->ndev.dev->dev_addr, ETH_ALEN);
+	else
+		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;
+}