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, 846 insertions, 0 deletions

diff --git a/drivers/infiniband/core/iwpm_msg.c b/drivers/infiniband/core/iwpm_msg.c
new file mode 100644
index 000000000..3c9a98692
--- /dev/null
+++ b/drivers/infiniband/core/iwpm_msg.c
@@ -0,0 +1,846 @@
+/*
+ * Copyright (c) 2014 Intel Corporation. All rights reserved.
+ * Copyright (c) 2014 Chelsio, Inc. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "iwpm_util.h"
+
+static const char iwpm_ulib_name[IWPM_ULIBNAME_SIZE] = "iWarpPortMapperUser";
+u16 iwpm_ulib_version = IWPM_UABI_VERSION_MIN;
+static int iwpm_user_pid = IWPM_PID_UNDEFINED;
+static atomic_t echo_nlmsg_seq;
+
+/**
+ * iwpm_valid_pid - Check if the userspace iwarp port mapper pid is valid
+ *
+ * Returns true if the pid is greater than zero, otherwise returns false
+ */
+int iwpm_valid_pid(void)
+{
+	return iwpm_user_pid > 0;
+}
+
+/**
+ * iwpm_register_pid - Send a netlink query to userspace
+ *                     to get the iwarp port mapper pid
+ * @pm_msg: Contains driver info to send to the userspace port mapper
+ * @nl_client: The index of the netlink client
+ *
+ * nlmsg attributes:
+ *	[IWPM_NLA_REG_PID_SEQ]
+ *	[IWPM_NLA_REG_IF_NAME]
+ *	[IWPM_NLA_REG_IBDEV_NAME]
+ *	[IWPM_NLA_REG_ULIB_NAME]
+ */
+int iwpm_register_pid(struct iwpm_dev_data *pm_msg, u8 nl_client)
+{
+	struct sk_buff *skb = NULL;
+	struct iwpm_nlmsg_request *nlmsg_request = NULL;
+	struct nlmsghdr *nlh;
+	u32 msg_seq;
+	const char *err_str = "";
+	int ret = -EINVAL;
+
+	if (iwpm_check_registration(nl_client, IWPM_REG_VALID) ||
+			iwpm_user_pid == IWPM_PID_UNAVAILABLE)
+		return 0;
+	skb = iwpm_create_nlmsg(RDMA_NL_IWPM_REG_PID, &nlh, nl_client);
+	if (!skb) {
+		err_str = "Unable to create a nlmsg";
+		goto pid_query_error;
+	}
+	nlh->nlmsg_seq = iwpm_get_nlmsg_seq();
+	nlmsg_request = iwpm_get_nlmsg_request(nlh->nlmsg_seq, nl_client, GFP_KERNEL);
+	if (!nlmsg_request) {
+		err_str = "Unable to allocate netlink request";
+		goto pid_query_error;
+	}
+	msg_seq = atomic_read(&echo_nlmsg_seq);
+
+	/* fill in the pid request message */
+	err_str = "Unable to put attribute of the nlmsg";
+	ret = ibnl_put_attr(skb, nlh, sizeof(u32), &msg_seq, IWPM_NLA_REG_PID_SEQ);
+	if (ret)
+		goto pid_query_error;
+	ret = ibnl_put_attr(skb, nlh, IFNAMSIZ,
+			    pm_msg->if_name, IWPM_NLA_REG_IF_NAME);
+	if (ret)
+		goto pid_query_error;
+	ret = ibnl_put_attr(skb, nlh, IWPM_DEVNAME_SIZE,
+				pm_msg->dev_name, IWPM_NLA_REG_IBDEV_NAME);
+	if (ret)
+		goto pid_query_error;
+	ret = ibnl_put_attr(skb, nlh, IWPM_ULIBNAME_SIZE,
+				(char *)iwpm_ulib_name, IWPM_NLA_REG_ULIB_NAME);
+	if (ret)
+		goto pid_query_error;
+
+	nlmsg_end(skb, nlh);
+
+	pr_debug("%s: Multicasting a nlmsg (dev = %s ifname = %s iwpm = %s)\n",
+		__func__, pm_msg->dev_name, pm_msg->if_name, iwpm_ulib_name);
+
+	ret = rdma_nl_multicast(&init_net, skb, RDMA_NL_GROUP_IWPM, GFP_KERNEL);
+	if (ret) {
+		skb = NULL; /* skb is freed in the netlink send-op handling */
+		iwpm_user_pid = IWPM_PID_UNAVAILABLE;
+		err_str = "Unable to send a nlmsg";
+		goto pid_query_error;
+	}
+	nlmsg_request->req_buffer = pm_msg;
+	ret = iwpm_wait_complete_req(nlmsg_request);
+	return ret;
+pid_query_error:
+	pr_info("%s: %s (client = %u)\n", __func__, err_str, nl_client);
+	dev_kfree_skb(skb);
+	if (nlmsg_request)
+		iwpm_free_nlmsg_request(&nlmsg_request->kref);
+	return ret;
+}
+
+/**
+ * iwpm_add_mapping - Send a netlink add mapping request to
+ *                    the userspace port mapper
+ * @pm_msg: Contains the local ip/tcp address info to send
+ * @nl_client: The index of the netlink client
+ *
+ * nlmsg attributes:
+ *	[IWPM_NLA_MANAGE_MAPPING_SEQ]
+ *	[IWPM_NLA_MANAGE_ADDR]
+ *	[IWPM_NLA_MANAGE_FLAGS]
+ *
+ * If the request is successful, the pm_msg stores
+ * the port mapper response (mapped address info)
+ */
+int iwpm_add_mapping(struct iwpm_sa_data *pm_msg, u8 nl_client)
+{
+	struct sk_buff *skb = NULL;
+	struct iwpm_nlmsg_request *nlmsg_request = NULL;
+	struct nlmsghdr *nlh;
+	u32 msg_seq;
+	const char *err_str = "";
+	int ret = -EINVAL;
+
+	if (!iwpm_valid_pid())
+		return 0;
+	if (!iwpm_check_registration(nl_client, IWPM_REG_VALID)) {
+		err_str = "Unregistered port mapper client";
+		goto add_mapping_error;
+	}
+	skb = iwpm_create_nlmsg(RDMA_NL_IWPM_ADD_MAPPING, &nlh, nl_client);
+	if (!skb) {
+		err_str = "Unable to create a nlmsg";
+		goto add_mapping_error;
+	}
+	nlh->nlmsg_seq = iwpm_get_nlmsg_seq();
+	nlmsg_request = iwpm_get_nlmsg_request(nlh->nlmsg_seq, nl_client, GFP_KERNEL);
+	if (!nlmsg_request) {
+		err_str = "Unable to allocate netlink request";
+		goto add_mapping_error;
+	}
+	msg_seq = atomic_read(&echo_nlmsg_seq);
+	/* fill in the add mapping message */
+	err_str = "Unable to put attribute of the nlmsg";
+	ret = ibnl_put_attr(skb, nlh, sizeof(u32), &msg_seq,
+				IWPM_NLA_MANAGE_MAPPING_SEQ);
+	if (ret)
+		goto add_mapping_error;
+	ret = ibnl_put_attr(skb, nlh, sizeof(struct sockaddr_storage),
+				&pm_msg->loc_addr, IWPM_NLA_MANAGE_ADDR);
+	if (ret)
+		goto add_mapping_error;
+
+	/* If flags are required and we're not V4, then return a quiet error */
+	if (pm_msg->flags && iwpm_ulib_version == IWPM_UABI_VERSION_MIN) {
+		ret = -EINVAL;
+		goto add_mapping_error_nowarn;
+	}
+	if (iwpm_ulib_version > IWPM_UABI_VERSION_MIN) {
+		ret = ibnl_put_attr(skb, nlh, sizeof(u32), &pm_msg->flags,
+				IWPM_NLA_MANAGE_FLAGS);
+		if (ret)
+			goto add_mapping_error;
+	}
+
+	nlmsg_end(skb, nlh);
+	nlmsg_request->req_buffer = pm_msg;
+
+	ret = rdma_nl_unicast_wait(&init_net, skb, iwpm_user_pid);
+	if (ret) {
+		skb = NULL; /* skb is freed in the netlink send-op handling */
+		iwpm_user_pid = IWPM_PID_UNDEFINED;
+		err_str = "Unable to send a nlmsg";
+		goto add_mapping_error;
+	}
+	ret = iwpm_wait_complete_req(nlmsg_request);
+	return ret;
+add_mapping_error:
+	pr_info("%s: %s (client = %u)\n", __func__, err_str, nl_client);
+add_mapping_error_nowarn:
+	dev_kfree_skb(skb);
+	if (nlmsg_request)
+		iwpm_free_nlmsg_request(&nlmsg_request->kref);
+	return ret;
+}
+
+/**
+ * iwpm_add_and_query_mapping - Process the port mapper response to
+ *                              iwpm_add_and_query_mapping request
+ * @pm_msg: Contains the local ip/tcp address info to send
+ * @nl_client: The index of the netlink client
+ *
+ * nlmsg attributes:
+ *	[IWPM_NLA_QUERY_MAPPING_SEQ]
+ *	[IWPM_NLA_QUERY_LOCAL_ADDR]
+ *	[IWPM_NLA_QUERY_REMOTE_ADDR]
+ *	[IWPM_NLA_QUERY_FLAGS]
+ */
+int iwpm_add_and_query_mapping(struct iwpm_sa_data *pm_msg, u8 nl_client)
+{
+	struct sk_buff *skb = NULL;
+	struct iwpm_nlmsg_request *nlmsg_request = NULL;
+	struct nlmsghdr *nlh;
+	u32 msg_seq;
+	const char *err_str = "";
+	int ret = -EINVAL;
+
+	if (!iwpm_valid_pid())
+		return 0;
+	if (!iwpm_check_registration(nl_client, IWPM_REG_VALID)) {
+		err_str = "Unregistered port mapper client";
+		goto query_mapping_error;
+	}
+	ret = -ENOMEM;
+	skb = iwpm_create_nlmsg(RDMA_NL_IWPM_QUERY_MAPPING, &nlh, nl_client);
+	if (!skb) {
+		err_str = "Unable to create a nlmsg";
+		goto query_mapping_error;
+	}
+	nlh->nlmsg_seq = iwpm_get_nlmsg_seq();
+	nlmsg_request = iwpm_get_nlmsg_request(nlh->nlmsg_seq,
+				nl_client, GFP_KERNEL);
+	if (!nlmsg_request) {
+		err_str = "Unable to allocate netlink request";
+		goto query_mapping_error;
+	}
+	msg_seq = atomic_read(&echo_nlmsg_seq);
+
+	/* fill in the query message */
+	err_str = "Unable to put attribute of the nlmsg";
+	ret = ibnl_put_attr(skb, nlh, sizeof(u32), &msg_seq,
+				IWPM_NLA_QUERY_MAPPING_SEQ);
+	if (ret)
+		goto query_mapping_error;
+	ret = ibnl_put_attr(skb, nlh, sizeof(struct sockaddr_storage),
+				&pm_msg->loc_addr, IWPM_NLA_QUERY_LOCAL_ADDR);
+	if (ret)
+		goto query_mapping_error;
+	ret = ibnl_put_attr(skb, nlh, sizeof(struct sockaddr_storage),
+				&pm_msg->rem_addr, IWPM_NLA_QUERY_REMOTE_ADDR);
+	if (ret)
+		goto query_mapping_error;
+
+	/* If flags are required and we're not V4, then return a quite error */
+	if (pm_msg->flags && iwpm_ulib_version == IWPM_UABI_VERSION_MIN) {
+		ret = -EINVAL;
+		goto query_mapping_error_nowarn;
+	}
+	if (iwpm_ulib_version > IWPM_UABI_VERSION_MIN) {
+		ret = ibnl_put_attr(skb, nlh, sizeof(u32), &pm_msg->flags,
+				IWPM_NLA_QUERY_FLAGS);
+		if (ret)
+			goto query_mapping_error;
+	}
+
+	nlmsg_end(skb, nlh);
+	nlmsg_request->req_buffer = pm_msg;
+
+	ret = rdma_nl_unicast_wait(&init_net, skb, iwpm_user_pid);
+	if (ret) {
+		skb = NULL; /* skb is freed in the netlink send-op handling */
+		err_str = "Unable to send a nlmsg";
+		goto query_mapping_error;
+	}
+	ret = iwpm_wait_complete_req(nlmsg_request);
+	return ret;
+query_mapping_error:
+	pr_info("%s: %s (client = %u)\n", __func__, err_str, nl_client);
+query_mapping_error_nowarn:
+	dev_kfree_skb(skb);
+	if (nlmsg_request)
+		iwpm_free_nlmsg_request(&nlmsg_request->kref);
+	return ret;
+}
+
+/**
+ * iwpm_remove_mapping - Send a netlink remove mapping request
+ *                       to the userspace port mapper
+ *
+ * @local_addr: Local ip/tcp address to remove
+ * @nl_client: The index of the netlink client
+ *
+ * nlmsg attributes:
+ *	[IWPM_NLA_MANAGE_MAPPING_SEQ]
+ *	[IWPM_NLA_MANAGE_ADDR]
+ */
+int iwpm_remove_mapping(struct sockaddr_storage *local_addr, u8 nl_client)
+{
+	struct sk_buff *skb = NULL;
+	struct nlmsghdr *nlh;
+	u32 msg_seq;
+	const char *err_str = "";
+	int ret = -EINVAL;
+
+	if (!iwpm_valid_pid())
+		return 0;
+	if (iwpm_check_registration(nl_client, IWPM_REG_UNDEF)) {
+		err_str = "Unregistered port mapper client";
+		goto remove_mapping_error;
+	}
+	skb = iwpm_create_nlmsg(RDMA_NL_IWPM_REMOVE_MAPPING, &nlh, nl_client);
+	if (!skb) {
+		ret = -ENOMEM;
+		err_str = "Unable to create a nlmsg";
+		goto remove_mapping_error;
+	}
+	msg_seq = atomic_read(&echo_nlmsg_seq);
+	nlh->nlmsg_seq = iwpm_get_nlmsg_seq();
+	err_str = "Unable to put attribute of the nlmsg";
+	ret = ibnl_put_attr(skb, nlh, sizeof(u32), &msg_seq,
+				IWPM_NLA_MANAGE_MAPPING_SEQ);
+	if (ret)
+		goto remove_mapping_error;
+	ret = ibnl_put_attr(skb, nlh, sizeof(struct sockaddr_storage),
+				local_addr, IWPM_NLA_MANAGE_ADDR);
+	if (ret)
+		goto remove_mapping_error;
+
+	nlmsg_end(skb, nlh);
+
+	ret = rdma_nl_unicast_wait(&init_net, skb, iwpm_user_pid);
+	if (ret) {
+		skb = NULL; /* skb is freed in the netlink send-op handling */
+		iwpm_user_pid = IWPM_PID_UNDEFINED;
+		err_str = "Unable to send a nlmsg";
+		goto remove_mapping_error;
+	}
+	iwpm_print_sockaddr(local_addr,
+			"remove_mapping: Local sockaddr:");
+	return 0;
+remove_mapping_error:
+	pr_info("%s: %s (client = %u)\n", __func__, err_str, nl_client);
+	if (skb)
+		dev_kfree_skb_any(skb);
+	return ret;
+}
+
+/* netlink attribute policy for the received response to register pid request */
+static const struct nla_policy resp_reg_policy[IWPM_NLA_RREG_PID_MAX] = {
+	[IWPM_NLA_RREG_PID_SEQ]     = { .type = NLA_U32 },
+	[IWPM_NLA_RREG_IBDEV_NAME]  = { .type = NLA_STRING,
+					.len = IWPM_DEVNAME_SIZE - 1 },
+	[IWPM_NLA_RREG_ULIB_NAME]   = { .type = NLA_STRING,
+					.len = IWPM_ULIBNAME_SIZE - 1 },
+	[IWPM_NLA_RREG_ULIB_VER]    = { .type = NLA_U16 },
+	[IWPM_NLA_RREG_PID_ERR]     = { .type = NLA_U16 }
+};
+
+/**
+ * iwpm_register_pid_cb - Process the port mapper response to
+ *                        iwpm_register_pid query
+ * @skb: The socket buffer
+ * @cb: Contains the received message (payload and netlink header)
+ *
+ * If successful, the function receives the userspace port mapper pid
+ * which is used in future communication with the port mapper
+ */
+int iwpm_register_pid_cb(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct iwpm_nlmsg_request *nlmsg_request = NULL;
+	struct nlattr *nltb[IWPM_NLA_RREG_PID_MAX];
+	struct iwpm_dev_data *pm_msg;
+	char *dev_name, *iwpm_name;
+	u32 msg_seq;
+	u8 nl_client;
+	u16 iwpm_version;
+	const char *msg_type = "Register Pid response";
+
+	if (iwpm_parse_nlmsg(cb, IWPM_NLA_RREG_PID_MAX,
+				resp_reg_policy, nltb, msg_type))
+		return -EINVAL;
+
+	msg_seq = nla_get_u32(nltb[IWPM_NLA_RREG_PID_SEQ]);
+	nlmsg_request = iwpm_find_nlmsg_request(msg_seq);
+	if (!nlmsg_request) {
+		pr_info("%s: Could not find a matching request (seq = %u)\n",
+				 __func__, msg_seq);
+		return -EINVAL;
+	}
+	pm_msg = nlmsg_request->req_buffer;
+	nl_client = nlmsg_request->nl_client;
+	dev_name = (char *)nla_data(nltb[IWPM_NLA_RREG_IBDEV_NAME]);
+	iwpm_name = (char *)nla_data(nltb[IWPM_NLA_RREG_ULIB_NAME]);
+	iwpm_version = nla_get_u16(nltb[IWPM_NLA_RREG_ULIB_VER]);
+
+	/* check device name, ulib name and version */
+	if (strcmp(pm_msg->dev_name, dev_name) ||
+			strcmp(iwpm_ulib_name, iwpm_name) ||
+			iwpm_version < IWPM_UABI_VERSION_MIN) {
+
+		pr_info("%s: Incorrect info (dev = %s name = %s version = %u)\n",
+				__func__, dev_name, iwpm_name, iwpm_version);
+		nlmsg_request->err_code = IWPM_USER_LIB_INFO_ERR;
+		goto register_pid_response_exit;
+	}
+	iwpm_user_pid = cb->nlh->nlmsg_pid;
+	iwpm_ulib_version = iwpm_version;
+	if (iwpm_ulib_version < IWPM_UABI_VERSION)
+		pr_warn_once("%s: Down level iwpmd/pid %d.  Continuing...",
+			__func__, iwpm_user_pid);
+	atomic_set(&echo_nlmsg_seq, cb->nlh->nlmsg_seq);
+	pr_debug("%s: iWarp Port Mapper (pid = %d) is available!\n",
+			__func__, iwpm_user_pid);
+	iwpm_set_registration(nl_client, IWPM_REG_VALID);
+register_pid_response_exit:
+	nlmsg_request->request_done = 1;
+	/* always for found nlmsg_request */
+	kref_put(&nlmsg_request->kref, iwpm_free_nlmsg_request);
+	barrier();
+	up(&nlmsg_request->sem);
+	return 0;
+}
+
+/* netlink attribute policy for the received response to add mapping request */
+static const struct nla_policy resp_add_policy[IWPM_NLA_RMANAGE_MAPPING_MAX] = {
+	[IWPM_NLA_RMANAGE_MAPPING_SEQ]     = { .type = NLA_U32 },
+	[IWPM_NLA_RMANAGE_ADDR]            = {
+				.len = sizeof(struct sockaddr_storage) },
+	[IWPM_NLA_RMANAGE_MAPPED_LOC_ADDR] = {
+				.len = sizeof(struct sockaddr_storage) },
+	[IWPM_NLA_RMANAGE_MAPPING_ERR]	   = { .type = NLA_U16 }
+};
+
+/**
+ * iwpm_add_mapping_cb - Process the port mapper response to
+ *                       iwpm_add_mapping request
+ * @skb: The socket buffer
+ * @cb: Contains the received message (payload and netlink header)
+ */
+int iwpm_add_mapping_cb(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct iwpm_sa_data *pm_msg;
+	struct iwpm_nlmsg_request *nlmsg_request = NULL;
+	struct nlattr *nltb[IWPM_NLA_RMANAGE_MAPPING_MAX];
+	struct sockaddr_storage *local_sockaddr;
+	struct sockaddr_storage *mapped_sockaddr;
+	const char *msg_type;
+	u32 msg_seq;
+
+	msg_type = "Add Mapping response";
+	if (iwpm_parse_nlmsg(cb, IWPM_NLA_RMANAGE_MAPPING_MAX,
+				resp_add_policy, nltb, msg_type))
+		return -EINVAL;
+
+	atomic_set(&echo_nlmsg_seq, cb->nlh->nlmsg_seq);
+
+	msg_seq = nla_get_u32(nltb[IWPM_NLA_RMANAGE_MAPPING_SEQ]);
+	nlmsg_request = iwpm_find_nlmsg_request(msg_seq);
+	if (!nlmsg_request) {
+		pr_info("%s: Could not find a matching request (seq = %u)\n",
+				 __func__, msg_seq);
+		return -EINVAL;
+	}
+	pm_msg = nlmsg_request->req_buffer;
+	local_sockaddr = (struct sockaddr_storage *)
+			nla_data(nltb[IWPM_NLA_RMANAGE_ADDR]);
+	mapped_sockaddr = (struct sockaddr_storage *)
+			nla_data(nltb[IWPM_NLA_RMANAGE_MAPPED_LOC_ADDR]);
+
+	if (iwpm_compare_sockaddr(local_sockaddr, &pm_msg->loc_addr)) {
+		nlmsg_request->err_code = IWPM_USER_LIB_INFO_ERR;
+		goto add_mapping_response_exit;
+	}
+	if (mapped_sockaddr->ss_family != local_sockaddr->ss_family) {
+		pr_info("%s: Sockaddr family doesn't match the requested one\n",
+				__func__);
+		nlmsg_request->err_code = IWPM_USER_LIB_INFO_ERR;
+		goto add_mapping_response_exit;
+	}
+	memcpy(&pm_msg->mapped_loc_addr, mapped_sockaddr,
+			sizeof(*mapped_sockaddr));
+	iwpm_print_sockaddr(&pm_msg->loc_addr,
+			"add_mapping: Local sockaddr:");
+	iwpm_print_sockaddr(&pm_msg->mapped_loc_addr,
+			"add_mapping: Mapped local sockaddr:");
+
+add_mapping_response_exit:
+	nlmsg_request->request_done = 1;
+	/* always for found request */
+	kref_put(&nlmsg_request->kref, iwpm_free_nlmsg_request);
+	barrier();
+	up(&nlmsg_request->sem);
+	return 0;
+}
+
+/* netlink attribute policy for the response to add and query mapping request
+ * and response with remote address info
+ */
+static const struct nla_policy resp_query_policy[IWPM_NLA_RQUERY_MAPPING_MAX] = {
+	[IWPM_NLA_RQUERY_MAPPING_SEQ]     = { .type = NLA_U32 },
+	[IWPM_NLA_RQUERY_LOCAL_ADDR]      = {
+				.len = sizeof(struct sockaddr_storage) },
+	[IWPM_NLA_RQUERY_REMOTE_ADDR]     = {
+				.len = sizeof(struct sockaddr_storage) },
+	[IWPM_NLA_RQUERY_MAPPED_LOC_ADDR] = {
+				.len = sizeof(struct sockaddr_storage) },
+	[IWPM_NLA_RQUERY_MAPPED_REM_ADDR] = {
+				.len = sizeof(struct sockaddr_storage) },
+	[IWPM_NLA_RQUERY_MAPPING_ERR]	  = { .type = NLA_U16 }
+};
+
+/**
+ * iwpm_add_and_query_mapping_cb - Process the port mapper response to
+ *                                 iwpm_add_and_query_mapping request
+ * @skb: The socket buffer
+ * @cb: Contains the received message (payload and netlink header)
+ */
+int iwpm_add_and_query_mapping_cb(struct sk_buff *skb,
+				struct netlink_callback *cb)
+{
+	struct iwpm_sa_data *pm_msg;
+	struct iwpm_nlmsg_request *nlmsg_request = NULL;
+	struct nlattr *nltb[IWPM_NLA_RQUERY_MAPPING_MAX];
+	struct sockaddr_storage *local_sockaddr, *remote_sockaddr;
+	struct sockaddr_storage *mapped_loc_sockaddr, *mapped_rem_sockaddr;
+	const char *msg_type;
+	u32 msg_seq;
+	u16 err_code;
+
+	msg_type = "Query Mapping response";
+	if (iwpm_parse_nlmsg(cb, IWPM_NLA_RQUERY_MAPPING_MAX,
+				resp_query_policy, nltb, msg_type))
+		return -EINVAL;
+	atomic_set(&echo_nlmsg_seq, cb->nlh->nlmsg_seq);
+
+	msg_seq = nla_get_u32(nltb[IWPM_NLA_RQUERY_MAPPING_SEQ]);
+	nlmsg_request = iwpm_find_nlmsg_request(msg_seq);
+	if (!nlmsg_request) {
+		pr_info("%s: Could not find a matching request (seq = %u)\n",
+				 __func__, msg_seq);
+		return -EINVAL;
+	}
+	pm_msg = nlmsg_request->req_buffer;
+	local_sockaddr = (struct sockaddr_storage *)
+			nla_data(nltb[IWPM_NLA_RQUERY_LOCAL_ADDR]);
+	remote_sockaddr = (struct sockaddr_storage *)
+			nla_data(nltb[IWPM_NLA_RQUERY_REMOTE_ADDR]);
+	mapped_loc_sockaddr = (struct sockaddr_storage *)
+			nla_data(nltb[IWPM_NLA_RQUERY_MAPPED_LOC_ADDR]);
+	mapped_rem_sockaddr = (struct sockaddr_storage *)
+			nla_data(nltb[IWPM_NLA_RQUERY_MAPPED_REM_ADDR]);
+
+	err_code = nla_get_u16(nltb[IWPM_NLA_RQUERY_MAPPING_ERR]);
+	if (err_code == IWPM_REMOTE_QUERY_REJECT) {
+		pr_info("%s: Received a Reject (pid = %u, echo seq = %u)\n",
+			__func__, cb->nlh->nlmsg_pid, msg_seq);
+		nlmsg_request->err_code = IWPM_REMOTE_QUERY_REJECT;
+	}
+	if (iwpm_compare_sockaddr(local_sockaddr, &pm_msg->loc_addr) ||
+		iwpm_compare_sockaddr(remote_sockaddr, &pm_msg->rem_addr)) {
+		pr_info("%s: Incorrect local sockaddr\n", __func__);
+		nlmsg_request->err_code = IWPM_USER_LIB_INFO_ERR;
+		goto query_mapping_response_exit;
+	}
+	if (mapped_loc_sockaddr->ss_family != local_sockaddr->ss_family ||
+		mapped_rem_sockaddr->ss_family != remote_sockaddr->ss_family) {
+		pr_info("%s: Sockaddr family doesn't match the requested one\n",
+				__func__);
+		nlmsg_request->err_code = IWPM_USER_LIB_INFO_ERR;
+		goto query_mapping_response_exit;
+	}
+	memcpy(&pm_msg->mapped_loc_addr, mapped_loc_sockaddr,
+			sizeof(*mapped_loc_sockaddr));
+	memcpy(&pm_msg->mapped_rem_addr, mapped_rem_sockaddr,
+			sizeof(*mapped_rem_sockaddr));
+
+	iwpm_print_sockaddr(&pm_msg->loc_addr,
+			"query_mapping: Local sockaddr:");
+	iwpm_print_sockaddr(&pm_msg->mapped_loc_addr,
+			"query_mapping: Mapped local sockaddr:");
+	iwpm_print_sockaddr(&pm_msg->rem_addr,
+			"query_mapping: Remote sockaddr:");
+	iwpm_print_sockaddr(&pm_msg->mapped_rem_addr,
+			"query_mapping: Mapped remote sockaddr:");
+query_mapping_response_exit:
+	nlmsg_request->request_done = 1;
+	/* always for found request */
+	kref_put(&nlmsg_request->kref, iwpm_free_nlmsg_request);
+	barrier();
+	up(&nlmsg_request->sem);
+	return 0;
+}
+
+/**
+ * iwpm_remote_info_cb - Process remote connecting peer address info, which
+ *                       the port mapper has received from the connecting peer
+ * @skb: The socket buffer
+ * @cb: Contains the received message (payload and netlink header)
+ *
+ * Stores the IPv4/IPv6 address info in a hash table
+ */
+int iwpm_remote_info_cb(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct nlattr *nltb[IWPM_NLA_RQUERY_MAPPING_MAX];
+	struct sockaddr_storage *local_sockaddr, *remote_sockaddr;
+	struct sockaddr_storage *mapped_loc_sockaddr, *mapped_rem_sockaddr;
+	struct iwpm_remote_info *rem_info;
+	const char *msg_type;
+	u8 nl_client;
+	int ret = -EINVAL;
+
+	msg_type = "Remote Mapping info";
+	if (iwpm_parse_nlmsg(cb, IWPM_NLA_RQUERY_MAPPING_MAX,
+				resp_query_policy, nltb, msg_type))
+		return ret;
+
+	nl_client = RDMA_NL_GET_CLIENT(cb->nlh->nlmsg_type);
+	atomic_set(&echo_nlmsg_seq, cb->nlh->nlmsg_seq);
+
+	local_sockaddr = (struct sockaddr_storage *)
+			nla_data(nltb[IWPM_NLA_RQUERY_LOCAL_ADDR]);
+	remote_sockaddr = (struct sockaddr_storage *)
+			nla_data(nltb[IWPM_NLA_RQUERY_REMOTE_ADDR]);
+	mapped_loc_sockaddr = (struct sockaddr_storage *)
+			nla_data(nltb[IWPM_NLA_RQUERY_MAPPED_LOC_ADDR]);
+	mapped_rem_sockaddr = (struct sockaddr_storage *)
+			nla_data(nltb[IWPM_NLA_RQUERY_MAPPED_REM_ADDR]);
+
+	if (mapped_loc_sockaddr->ss_family != local_sockaddr->ss_family ||
+		mapped_rem_sockaddr->ss_family != remote_sockaddr->ss_family) {
+		pr_info("%s: Sockaddr family doesn't match the requested one\n",
+				__func__);
+		return ret;
+	}
+	rem_info = kzalloc(sizeof(struct iwpm_remote_info), GFP_ATOMIC);
+	if (!rem_info) {
+		ret = -ENOMEM;
+		return ret;
+	}
+	memcpy(&rem_info->mapped_loc_sockaddr, mapped_loc_sockaddr,
+	       sizeof(struct sockaddr_storage));
+	memcpy(&rem_info->remote_sockaddr, remote_sockaddr,
+	       sizeof(struct sockaddr_storage));
+	memcpy(&rem_info->mapped_rem_sockaddr, mapped_rem_sockaddr,
+	       sizeof(struct sockaddr_storage));
+	rem_info->nl_client = nl_client;
+
+	iwpm_add_remote_info(rem_info);
+
+	iwpm_print_sockaddr(local_sockaddr,
+			"remote_info: Local sockaddr:");
+	iwpm_print_sockaddr(mapped_loc_sockaddr,
+			"remote_info: Mapped local sockaddr:");
+	iwpm_print_sockaddr(remote_sockaddr,
+			"remote_info: Remote sockaddr:");
+	iwpm_print_sockaddr(mapped_rem_sockaddr,
+			"remote_info: Mapped remote sockaddr:");
+	return ret;
+}
+
+/* netlink attribute policy for the received request for mapping info */
+static const struct nla_policy resp_mapinfo_policy[IWPM_NLA_MAPINFO_REQ_MAX] = {
+	[IWPM_NLA_MAPINFO_ULIB_NAME] = { .type = NLA_STRING,
+					.len = IWPM_ULIBNAME_SIZE - 1 },
+	[IWPM_NLA_MAPINFO_ULIB_VER]  = { .type = NLA_U16 }
+};
+
+/**
+ * iwpm_mapping_info_cb - Process a notification that the userspace
+ *                        port mapper daemon is started
+ * @skb: The socket buffer
+ * @cb: Contains the received message (payload and netlink header)
+ *
+ * Using the received port mapper pid, send all the local mapping
+ * info records to the userspace port mapper
+ */
+int iwpm_mapping_info_cb(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct nlattr *nltb[IWPM_NLA_MAPINFO_REQ_MAX];
+	const char *msg_type = "Mapping Info response";
+	u8 nl_client;
+	char *iwpm_name;
+	u16 iwpm_version;
+	int ret = -EINVAL;
+
+	if (iwpm_parse_nlmsg(cb, IWPM_NLA_MAPINFO_REQ_MAX,
+				resp_mapinfo_policy, nltb, msg_type)) {
+		pr_info("%s: Unable to parse nlmsg\n", __func__);
+		return ret;
+	}
+	iwpm_name = (char *)nla_data(nltb[IWPM_NLA_MAPINFO_ULIB_NAME]);
+	iwpm_version = nla_get_u16(nltb[IWPM_NLA_MAPINFO_ULIB_VER]);
+	if (strcmp(iwpm_ulib_name, iwpm_name) ||
+			iwpm_version < IWPM_UABI_VERSION_MIN) {
+		pr_info("%s: Invalid port mapper name = %s version = %u\n",
+				__func__, iwpm_name, iwpm_version);
+		return ret;
+	}
+	nl_client = RDMA_NL_GET_CLIENT(cb->nlh->nlmsg_type);
+	iwpm_set_registration(nl_client, IWPM_REG_INCOMPL);
+	atomic_set(&echo_nlmsg_seq, cb->nlh->nlmsg_seq);
+	iwpm_user_pid = cb->nlh->nlmsg_pid;
+
+	if (iwpm_ulib_version < IWPM_UABI_VERSION)
+		pr_warn_once("%s: Down level iwpmd/pid %d.  Continuing...",
+			__func__, iwpm_user_pid);
+
+	if (!iwpm_mapinfo_available())
+		return 0;
+	pr_debug("%s: iWarp Port Mapper (pid = %d) is available!\n",
+		 __func__, iwpm_user_pid);
+	ret = iwpm_send_mapinfo(nl_client, iwpm_user_pid);
+	return ret;
+}
+
+/* netlink attribute policy for the received mapping info ack */
+static const struct nla_policy ack_mapinfo_policy[IWPM_NLA_MAPINFO_NUM_MAX] = {
+	[IWPM_NLA_MAPINFO_SEQ]    =   { .type = NLA_U32 },
+	[IWPM_NLA_MAPINFO_SEND_NUM] = { .type = NLA_U32 },
+	[IWPM_NLA_MAPINFO_ACK_NUM] =  { .type = NLA_U32 }
+};
+
+/**
+ * iwpm_ack_mapping_info_cb - Process the port mapper ack for
+ *                            the provided local mapping info records
+ * @skb: The socket buffer
+ * @cb: Contains the received message (payload and netlink header)
+ */
+int iwpm_ack_mapping_info_cb(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct nlattr *nltb[IWPM_NLA_MAPINFO_NUM_MAX];
+	u32 mapinfo_send, mapinfo_ack;
+	const char *msg_type = "Mapping Info Ack";
+
+	if (iwpm_parse_nlmsg(cb, IWPM_NLA_MAPINFO_NUM_MAX,
+				ack_mapinfo_policy, nltb, msg_type))
+		return -EINVAL;
+	mapinfo_send = nla_get_u32(nltb[IWPM_NLA_MAPINFO_SEND_NUM]);
+	mapinfo_ack = nla_get_u32(nltb[IWPM_NLA_MAPINFO_ACK_NUM]);
+	if (mapinfo_ack != mapinfo_send)
+		pr_info("%s: Invalid mapinfo number (sent = %u ack-ed = %u)\n",
+			__func__, mapinfo_send, mapinfo_ack);
+	atomic_set(&echo_nlmsg_seq, cb->nlh->nlmsg_seq);
+	return 0;
+}
+
+/* netlink attribute policy for the received port mapper error message */
+static const struct nla_policy map_error_policy[IWPM_NLA_ERR_MAX] = {
+	[IWPM_NLA_ERR_SEQ]        = { .type = NLA_U32 },
+	[IWPM_NLA_ERR_CODE]       = { .type = NLA_U16 },
+};
+
+/**
+ * iwpm_mapping_error_cb - Process port mapper notification for error
+ *
+ * @skb: The socket buffer
+ * @cb: Contains the received message (payload and netlink header)
+ */
+int iwpm_mapping_error_cb(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct iwpm_nlmsg_request *nlmsg_request = NULL;
+	int nl_client = RDMA_NL_GET_CLIENT(cb->nlh->nlmsg_type);
+	struct nlattr *nltb[IWPM_NLA_ERR_MAX];
+	u32 msg_seq;
+	u16 err_code;
+	const char *msg_type = "Mapping Error Msg";
+
+	if (iwpm_parse_nlmsg(cb, IWPM_NLA_ERR_MAX,
+				map_error_policy, nltb, msg_type))
+		return -EINVAL;
+
+	msg_seq = nla_get_u32(nltb[IWPM_NLA_ERR_SEQ]);
+	err_code = nla_get_u16(nltb[IWPM_NLA_ERR_CODE]);
+	pr_info("%s: Received msg seq = %u err code = %u client = %d\n",
+				__func__, msg_seq, err_code, nl_client);
+	/* look for nlmsg_request */
+	nlmsg_request = iwpm_find_nlmsg_request(msg_seq);
+	if (!nlmsg_request) {
+		/* not all errors have associated requests */
+		pr_debug("Could not find matching req (seq = %u)\n", msg_seq);
+		return 0;
+	}
+	atomic_set(&echo_nlmsg_seq, cb->nlh->nlmsg_seq);
+	nlmsg_request->err_code = err_code;
+	nlmsg_request->request_done = 1;
+	/* always for found request */
+	kref_put(&nlmsg_request->kref, iwpm_free_nlmsg_request);
+	barrier();
+	up(&nlmsg_request->sem);
+	return 0;
+}
+
+/* netlink attribute policy for the received hello request */
+static const struct nla_policy hello_policy[IWPM_NLA_HELLO_MAX] = {
+	[IWPM_NLA_HELLO_ABI_VERSION]     = { .type = NLA_U16 }
+};
+
+/**
+ * iwpm_hello_cb - Process a hello message from iwpmd
+ *
+ * @skb: The socket buffer
+ * @cb: Contains the received message (payload and netlink header)
+ *
+ * Using the received port mapper pid, send the kernel's abi_version
+ * after adjusting it to support the iwpmd version.
+ */
+int iwpm_hello_cb(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct nlattr *nltb[IWPM_NLA_HELLO_MAX];
+	const char *msg_type = "Hello request";
+	u8 nl_client;
+	u16 abi_version;
+	int ret = -EINVAL;
+
+	if (iwpm_parse_nlmsg(cb, IWPM_NLA_HELLO_MAX, hello_policy, nltb,
+			     msg_type)) {
+		pr_info("%s: Unable to parse nlmsg\n", __func__);
+		return ret;
+	}
+	abi_version = nla_get_u16(nltb[IWPM_NLA_HELLO_ABI_VERSION]);
+	nl_client = RDMA_NL_GET_CLIENT(cb->nlh->nlmsg_type);
+	iwpm_set_registration(nl_client, IWPM_REG_INCOMPL);
+	atomic_set(&echo_nlmsg_seq, cb->nlh->nlmsg_seq);
+	iwpm_ulib_version = min_t(u16, IWPM_UABI_VERSION, abi_version);
+	pr_debug("Using ABI version %u\n", iwpm_ulib_version);
+	iwpm_user_pid = cb->nlh->nlmsg_pid;
+	ret = iwpm_send_hello(nl_client, iwpm_user_pid, iwpm_ulib_version);
+	return ret;
+}