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, 420 insertions, 0 deletions

diff --git a/net/tipc/discover.c b/net/tipc/discover.c
new file mode 100644
index 000000000..685389d4b
--- /dev/null
+++ b/net/tipc/discover.c
@@ -0,0 +1,420 @@
+/*
+ * net/tipc/discover.c
+ *
+ * Copyright (c) 2003-2006, 2014-2018, Ericsson AB
+ * Copyright (c) 2005-2006, 2010-2011, Wind River Systems
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "core.h"
+#include "node.h"
+#include "discover.h"
+
+/* min delay during bearer start up */
+#define TIPC_DISC_INIT	msecs_to_jiffies(125)
+/* max delay if bearer has no links */
+#define TIPC_DISC_FAST	msecs_to_jiffies(1000)
+/* max delay if bearer has links */
+#define TIPC_DISC_SLOW	msecs_to_jiffies(60000)
+/* indicates no timer in use */
+#define TIPC_DISC_INACTIVE	0xffffffff
+
+/**
+ * struct tipc_discoverer - information about an ongoing link setup request
+ * @bearer_id: identity of bearer issuing requests
+ * @net: network namespace instance
+ * @dest: destination address for request messages
+ * @domain: network domain to which links can be established
+ * @num_nodes: number of nodes currently discovered (i.e. with an active link)
+ * @lock: spinlock for controlling access to requests
+ * @skb: request message to be (repeatedly) sent
+ * @timer: timer governing period between requests
+ * @timer_intv: current interval between requests (in ms)
+ */
+struct tipc_discoverer {
+	u32 bearer_id;
+	struct tipc_media_addr dest;
+	struct net *net;
+	u32 domain;
+	int num_nodes;
+	spinlock_t lock;
+	struct sk_buff *skb;
+	struct timer_list timer;
+	unsigned long timer_intv;
+};
+
+/**
+ * tipc_disc_init_msg - initialize a link setup message
+ * @net: the applicable net namespace
+ * @skb: buffer containing message
+ * @mtyp: message type (request or response)
+ * @b: ptr to bearer issuing message
+ */
+static void tipc_disc_init_msg(struct net *net, struct sk_buff *skb,
+			       u32 mtyp,  struct tipc_bearer *b)
+{
+	struct tipc_net *tn = tipc_net(net);
+	u32 dest_domain = b->domain;
+	struct tipc_msg *hdr;
+
+	hdr = buf_msg(skb);
+	tipc_msg_init(tn->trial_addr, hdr, LINK_CONFIG, mtyp,
+		      MAX_H_SIZE, dest_domain);
+	msg_set_size(hdr, MAX_H_SIZE + NODE_ID_LEN);
+	msg_set_non_seq(hdr, 1);
+	msg_set_node_sig(hdr, tn->random);
+	msg_set_node_capabilities(hdr, TIPC_NODE_CAPABILITIES);
+	msg_set_dest_domain(hdr, dest_domain);
+	msg_set_bc_netid(hdr, tn->net_id);
+	b->media->addr2msg(msg_media_addr(hdr), &b->addr);
+	msg_set_peer_net_hash(hdr, tipc_net_hash_mixes(net, tn->random));
+	msg_set_node_id(hdr, tipc_own_id(net));
+}
+
+static void tipc_disc_msg_xmit(struct net *net, u32 mtyp, u32 dst,
+			       u32 src, u32 sugg_addr,
+			       struct tipc_media_addr *maddr,
+			       struct tipc_bearer *b)
+{
+	struct tipc_msg *hdr;
+	struct sk_buff *skb;
+
+	skb = tipc_buf_acquire(MAX_H_SIZE + NODE_ID_LEN, GFP_ATOMIC);
+	if (!skb)
+		return;
+	hdr = buf_msg(skb);
+	tipc_disc_init_msg(net, skb, mtyp, b);
+	msg_set_sugg_node_addr(hdr, sugg_addr);
+	msg_set_dest_domain(hdr, dst);
+	tipc_bearer_xmit_skb(net, b->identity, skb, maddr);
+}
+
+/**
+ * disc_dupl_alert - issue node address duplication alert
+ * @b: pointer to bearer detecting duplication
+ * @node_addr: duplicated node address
+ * @media_addr: media address advertised by duplicated node
+ */
+static void disc_dupl_alert(struct tipc_bearer *b, u32 node_addr,
+			    struct tipc_media_addr *media_addr)
+{
+	char media_addr_str[64];
+
+	tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str),
+			       media_addr);
+	pr_warn("Duplicate %x using %s seen on <%s>\n", node_addr,
+		media_addr_str, b->name);
+}
+
+/* tipc_disc_addr_trial(): - handle an address uniqueness trial from peer
+ * Returns true if message should be dropped by caller, i.e., if it is a
+ * trial message or we are inside trial period. Otherwise false.
+ */
+static bool tipc_disc_addr_trial_msg(struct tipc_discoverer *d,
+				     struct tipc_media_addr *maddr,
+				     struct tipc_bearer *b,
+				     u32 dst, u32 src,
+				     u32 sugg_addr,
+				     u8 *peer_id,
+				     int mtyp)
+{
+	struct net *net = d->net;
+	struct tipc_net *tn = tipc_net(net);
+	u32 self = tipc_own_addr(net);
+	bool trial = time_before(jiffies, tn->addr_trial_end) && !self;
+
+	if (mtyp == DSC_TRIAL_FAIL_MSG) {
+		if (!trial)
+			return true;
+
+		/* Ignore if somebody else already gave new suggestion */
+		if (dst != tn->trial_addr)
+			return true;
+
+		/* Otherwise update trial address and restart trial period */
+		tn->trial_addr = sugg_addr;
+		msg_set_prevnode(buf_msg(d->skb), sugg_addr);
+		tn->addr_trial_end = jiffies + msecs_to_jiffies(1000);
+		return true;
+	}
+
+	/* Apply trial address if we just left trial period */
+	if (!trial && !self) {
+		schedule_work(&tn->work);
+		msg_set_prevnode(buf_msg(d->skb), tn->trial_addr);
+		msg_set_type(buf_msg(d->skb), DSC_REQ_MSG);
+	}
+
+	/* Accept regular link requests/responses only after trial period */
+	if (mtyp != DSC_TRIAL_MSG)
+		return trial;
+
+	sugg_addr = tipc_node_try_addr(net, peer_id, src);
+	if (sugg_addr)
+		tipc_disc_msg_xmit(net, DSC_TRIAL_FAIL_MSG, src,
+				   self, sugg_addr, maddr, b);
+	return true;
+}
+
+/**
+ * tipc_disc_rcv - handle incoming discovery message (request or response)
+ * @net: applicable net namespace
+ * @skb: buffer containing message
+ * @b: bearer that message arrived on
+ */
+void tipc_disc_rcv(struct net *net, struct sk_buff *skb,
+		   struct tipc_bearer *b)
+{
+	struct tipc_net *tn = tipc_net(net);
+	struct tipc_msg *hdr = buf_msg(skb);
+	u32 pnet_hash = msg_peer_net_hash(hdr);
+	u16 caps = msg_node_capabilities(hdr);
+	bool legacy = tn->legacy_addr_format;
+	u32 sugg = msg_sugg_node_addr(hdr);
+	u32 signature = msg_node_sig(hdr);
+	u8 peer_id[NODE_ID_LEN] = {0,};
+	u32 dst = msg_dest_domain(hdr);
+	u32 net_id = msg_bc_netid(hdr);
+	struct tipc_media_addr maddr;
+	u32 src = msg_prevnode(hdr);
+	u32 mtyp = msg_type(hdr);
+	bool dupl_addr = false;
+	bool respond = false;
+	u32 self;
+	int err;
+
+	if (skb_linearize(skb)) {
+		kfree_skb(skb);
+		return;
+	}
+	hdr = buf_msg(skb);
+
+	if (caps & TIPC_NODE_ID128)
+		memcpy(peer_id, msg_node_id(hdr), NODE_ID_LEN);
+	else
+		sprintf(peer_id, "%x", src);
+
+	err = b->media->msg2addr(b, &maddr, msg_media_addr(hdr));
+	kfree_skb(skb);
+	if (err || maddr.broadcast) {
+		pr_warn_ratelimited("Rcv corrupt discovery message\n");
+		return;
+	}
+	/* Ignore discovery messages from own node */
+	if (!memcmp(&maddr, &b->addr, sizeof(maddr)))
+		return;
+	if (net_id != tn->net_id)
+		return;
+	if (tipc_disc_addr_trial_msg(b->disc, &maddr, b, dst,
+				     src, sugg, peer_id, mtyp))
+		return;
+	self = tipc_own_addr(net);
+
+	/* Message from somebody using this node's address */
+	if (in_own_node(net, src)) {
+		disc_dupl_alert(b, self, &maddr);
+		return;
+	}
+	if (!tipc_in_scope(legacy, dst, self))
+		return;
+	if (!tipc_in_scope(legacy, b->domain, src))
+		return;
+	tipc_node_check_dest(net, src, peer_id, b, caps, signature, pnet_hash,
+			     &maddr, &respond, &dupl_addr);
+	if (dupl_addr)
+		disc_dupl_alert(b, src, &maddr);
+	if (!respond)
+		return;
+	if (mtyp != DSC_REQ_MSG)
+		return;
+	tipc_disc_msg_xmit(net, DSC_RESP_MSG, src, self, 0, &maddr, b);
+}
+
+/* tipc_disc_add_dest - increment set of discovered nodes
+ */
+void tipc_disc_add_dest(struct tipc_discoverer *d)
+{
+	spin_lock_bh(&d->lock);
+	d->num_nodes++;
+	spin_unlock_bh(&d->lock);
+}
+
+/* tipc_disc_remove_dest - decrement set of discovered nodes
+ */
+void tipc_disc_remove_dest(struct tipc_discoverer *d)
+{
+	int intv, num;
+
+	spin_lock_bh(&d->lock);
+	d->num_nodes--;
+	num = d->num_nodes;
+	intv = d->timer_intv;
+	if (!num && (intv == TIPC_DISC_INACTIVE || intv > TIPC_DISC_FAST))  {
+		d->timer_intv = TIPC_DISC_INIT;
+		mod_timer(&d->timer, jiffies + d->timer_intv);
+	}
+	spin_unlock_bh(&d->lock);
+}
+
+/* tipc_disc_timeout - send a periodic link setup request
+ * Called whenever a link setup request timer associated with a bearer expires.
+ * - Keep doubling time between sent request until limit is reached;
+ * - Hold at fast polling rate if we don't have any associated nodes
+ * - Otherwise hold at slow polling rate
+ */
+static void tipc_disc_timeout(struct timer_list *t)
+{
+	struct tipc_discoverer *d = from_timer(d, t, timer);
+	struct tipc_net *tn = tipc_net(d->net);
+	struct tipc_media_addr maddr;
+	struct sk_buff *skb = NULL;
+	struct net *net = d->net;
+	u32 bearer_id;
+
+	spin_lock_bh(&d->lock);
+
+	/* Stop searching if only desired node has been found */
+	if (tipc_node(d->domain) && d->num_nodes) {
+		d->timer_intv = TIPC_DISC_INACTIVE;
+		goto exit;
+	}
+
+	/* Did we just leave trial period ? */
+	if (!time_before(jiffies, tn->addr_trial_end) && !tipc_own_addr(net)) {
+		mod_timer(&d->timer, jiffies + TIPC_DISC_INIT);
+		spin_unlock_bh(&d->lock);
+		schedule_work(&tn->work);
+		return;
+	}
+
+	/* Adjust timeout interval according to discovery phase */
+	if (time_before(jiffies, tn->addr_trial_end)) {
+		d->timer_intv = TIPC_DISC_INIT;
+	} else {
+		d->timer_intv *= 2;
+		if (d->num_nodes && d->timer_intv > TIPC_DISC_SLOW)
+			d->timer_intv = TIPC_DISC_SLOW;
+		else if (!d->num_nodes && d->timer_intv > TIPC_DISC_FAST)
+			d->timer_intv = TIPC_DISC_FAST;
+		msg_set_type(buf_msg(d->skb), DSC_REQ_MSG);
+		msg_set_prevnode(buf_msg(d->skb), tn->trial_addr);
+	}
+
+	mod_timer(&d->timer, jiffies + d->timer_intv);
+	memcpy(&maddr, &d->dest, sizeof(maddr));
+	skb = skb_clone(d->skb, GFP_ATOMIC);
+	bearer_id = d->bearer_id;
+exit:
+	spin_unlock_bh(&d->lock);
+	if (skb)
+		tipc_bearer_xmit_skb(net, bearer_id, skb, &maddr);
+}
+
+/**
+ * tipc_disc_create - create object to send periodic link setup requests
+ * @net: the applicable net namespace
+ * @b: ptr to bearer issuing requests
+ * @dest: destination address for request messages
+ * @skb: pointer to created frame
+ *
+ * Return: 0 if successful, otherwise -errno.
+ */
+int tipc_disc_create(struct net *net, struct tipc_bearer *b,
+		     struct tipc_media_addr *dest, struct sk_buff **skb)
+{
+	struct tipc_net *tn = tipc_net(net);
+	struct tipc_discoverer *d;
+
+	d = kmalloc(sizeof(*d), GFP_ATOMIC);
+	if (!d)
+		return -ENOMEM;
+	d->skb = tipc_buf_acquire(MAX_H_SIZE + NODE_ID_LEN, GFP_ATOMIC);
+	if (!d->skb) {
+		kfree(d);
+		return -ENOMEM;
+	}
+	tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
+
+	/* Do we need an address trial period first ? */
+	if (!tipc_own_addr(net)) {
+		tn->addr_trial_end = jiffies + msecs_to_jiffies(1000);
+		msg_set_type(buf_msg(d->skb), DSC_TRIAL_MSG);
+	}
+	memcpy(&d->dest, dest, sizeof(*dest));
+	d->net = net;
+	d->bearer_id = b->identity;
+	d->domain = b->domain;
+	d->num_nodes = 0;
+	d->timer_intv = TIPC_DISC_INIT;
+	spin_lock_init(&d->lock);
+	timer_setup(&d->timer, tipc_disc_timeout, 0);
+	mod_timer(&d->timer, jiffies + d->timer_intv);
+	b->disc = d;
+	*skb = skb_clone(d->skb, GFP_ATOMIC);
+	return 0;
+}
+
+/**
+ * tipc_disc_delete - destroy object sending periodic link setup requests
+ * @d: ptr to link dest structure
+ */
+void tipc_disc_delete(struct tipc_discoverer *d)
+{
+	timer_shutdown_sync(&d->timer);
+	kfree_skb(d->skb);
+	kfree(d);
+}
+
+/**
+ * tipc_disc_reset - reset object to send periodic link setup requests
+ * @net: the applicable net namespace
+ * @b: ptr to bearer issuing requests
+ */
+void tipc_disc_reset(struct net *net, struct tipc_bearer *b)
+{
+	struct tipc_discoverer *d = b->disc;
+	struct tipc_media_addr maddr;
+	struct sk_buff *skb;
+
+	spin_lock_bh(&d->lock);
+	tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
+	d->net = net;
+	d->bearer_id = b->identity;
+	d->domain = b->domain;
+	d->num_nodes = 0;
+	d->timer_intv = TIPC_DISC_INIT;
+	memcpy(&maddr, &d->dest, sizeof(maddr));
+	mod_timer(&d->timer, jiffies + d->timer_intv);
+	skb = skb_clone(d->skb, GFP_ATOMIC);
+	spin_unlock_bh(&d->lock);
+	if (skb)
+		tipc_bearer_xmit_skb(net, b->identity, skb, &maddr);
+}