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, 983 insertions, 0 deletions

diff --git a/net/netrom/nr_route.c b/net/netrom/nr_route.c
new file mode 100644
index 000000000..baea3cbd7
--- /dev/null
+++ b/net/netrom/nr_route.c
@@ -0,0 +1,983 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ * Copyright Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
+ * Copyright Tomi Manninen OH2BNS (oh2bns@sral.fi)
+ */
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/slab.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <net/arp.h>
+#include <linux/if_arp.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/termios.h>	/* For TIOCINQ/OUTQ */
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/notifier.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <net/netrom.h>
+#include <linux/seq_file.h>
+#include <linux/export.h>
+
+static unsigned int nr_neigh_no = 1;
+
+static HLIST_HEAD(nr_node_list);
+static DEFINE_SPINLOCK(nr_node_list_lock);
+static HLIST_HEAD(nr_neigh_list);
+static DEFINE_SPINLOCK(nr_neigh_list_lock);
+
+static struct nr_node *nr_node_get(ax25_address *callsign)
+{
+	struct nr_node *found = NULL;
+	struct nr_node *nr_node;
+
+	spin_lock_bh(&nr_node_list_lock);
+	nr_node_for_each(nr_node, &nr_node_list)
+		if (ax25cmp(callsign, &nr_node->callsign) == 0) {
+			nr_node_hold(nr_node);
+			found = nr_node;
+			break;
+		}
+	spin_unlock_bh(&nr_node_list_lock);
+	return found;
+}
+
+static struct nr_neigh *nr_neigh_get_dev(ax25_address *callsign,
+					 struct net_device *dev)
+{
+	struct nr_neigh *found = NULL;
+	struct nr_neigh *nr_neigh;
+
+	spin_lock_bh(&nr_neigh_list_lock);
+	nr_neigh_for_each(nr_neigh, &nr_neigh_list)
+		if (ax25cmp(callsign, &nr_neigh->callsign) == 0 &&
+		    nr_neigh->dev == dev) {
+			nr_neigh_hold(nr_neigh);
+			found = nr_neigh;
+			break;
+		}
+	spin_unlock_bh(&nr_neigh_list_lock);
+	return found;
+}
+
+static void nr_remove_neigh(struct nr_neigh *);
+
+/*      re-sort the routes in quality order.    */
+static void re_sort_routes(struct nr_node *nr_node, int x, int y)
+{
+	if (nr_node->routes[y].quality > nr_node->routes[x].quality) {
+		if (nr_node->which == x)
+			nr_node->which = y;
+		else if (nr_node->which == y)
+			nr_node->which = x;
+
+		swap(nr_node->routes[x], nr_node->routes[y]);
+	}
+}
+
+/*
+ *	Add a new route to a node, and in the process add the node and the
+ *	neighbour if it is new.
+ */
+static int __must_check nr_add_node(ax25_address *nr, const char *mnemonic,
+	ax25_address *ax25, ax25_digi *ax25_digi, struct net_device *dev,
+	int quality, int obs_count)
+{
+	struct nr_node  *nr_node;
+	struct nr_neigh *nr_neigh;
+	int i, found;
+	struct net_device *odev;
+
+	if ((odev=nr_dev_get(nr)) != NULL) {	/* Can't add routes to ourself */
+		dev_put(odev);
+		return -EINVAL;
+	}
+
+	nr_node = nr_node_get(nr);
+
+	nr_neigh = nr_neigh_get_dev(ax25, dev);
+
+	/*
+	 * The L2 link to a neighbour has failed in the past
+	 * and now a frame comes from this neighbour. We assume
+	 * it was a temporary trouble with the link and reset the
+	 * routes now (and not wait for a node broadcast).
+	 */
+	if (nr_neigh != NULL && nr_neigh->failed != 0 && quality == 0) {
+		struct nr_node *nr_nodet;
+
+		spin_lock_bh(&nr_node_list_lock);
+		nr_node_for_each(nr_nodet, &nr_node_list) {
+			nr_node_lock(nr_nodet);
+			for (i = 0; i < nr_nodet->count; i++)
+				if (nr_nodet->routes[i].neighbour == nr_neigh)
+					if (i < nr_nodet->which)
+						nr_nodet->which = i;
+			nr_node_unlock(nr_nodet);
+		}
+		spin_unlock_bh(&nr_node_list_lock);
+	}
+
+	if (nr_neigh != NULL)
+		nr_neigh->failed = 0;
+
+	if (quality == 0 && nr_neigh != NULL && nr_node != NULL) {
+		nr_neigh_put(nr_neigh);
+		nr_node_put(nr_node);
+		return 0;
+	}
+
+	if (nr_neigh == NULL) {
+		if ((nr_neigh = kmalloc(sizeof(*nr_neigh), GFP_ATOMIC)) == NULL) {
+			if (nr_node)
+				nr_node_put(nr_node);
+			return -ENOMEM;
+		}
+
+		nr_neigh->callsign = *ax25;
+		nr_neigh->digipeat = NULL;
+		nr_neigh->ax25     = NULL;
+		nr_neigh->dev      = dev;
+		nr_neigh->quality  = sysctl_netrom_default_path_quality;
+		nr_neigh->locked   = 0;
+		nr_neigh->count    = 0;
+		nr_neigh->number   = nr_neigh_no++;
+		nr_neigh->failed   = 0;
+		refcount_set(&nr_neigh->refcount, 1);
+
+		if (ax25_digi != NULL && ax25_digi->ndigi > 0) {
+			nr_neigh->digipeat = kmemdup(ax25_digi,
+						     sizeof(*ax25_digi),
+						     GFP_KERNEL);
+			if (nr_neigh->digipeat == NULL) {
+				kfree(nr_neigh);
+				if (nr_node)
+					nr_node_put(nr_node);
+				return -ENOMEM;
+			}
+		}
+
+		spin_lock_bh(&nr_neigh_list_lock);
+		hlist_add_head(&nr_neigh->neigh_node, &nr_neigh_list);
+		nr_neigh_hold(nr_neigh);
+		spin_unlock_bh(&nr_neigh_list_lock);
+	}
+
+	if (quality != 0 && ax25cmp(nr, ax25) == 0 && !nr_neigh->locked)
+		nr_neigh->quality = quality;
+
+	if (nr_node == NULL) {
+		if ((nr_node = kmalloc(sizeof(*nr_node), GFP_ATOMIC)) == NULL) {
+			if (nr_neigh)
+				nr_neigh_put(nr_neigh);
+			return -ENOMEM;
+		}
+
+		nr_node->callsign = *nr;
+		strcpy(nr_node->mnemonic, mnemonic);
+
+		nr_node->which = 0;
+		nr_node->count = 1;
+		refcount_set(&nr_node->refcount, 1);
+		spin_lock_init(&nr_node->node_lock);
+
+		nr_node->routes[0].quality   = quality;
+		nr_node->routes[0].obs_count = obs_count;
+		nr_node->routes[0].neighbour = nr_neigh;
+
+		nr_neigh_hold(nr_neigh);
+		nr_neigh->count++;
+
+		spin_lock_bh(&nr_node_list_lock);
+		hlist_add_head(&nr_node->node_node, &nr_node_list);
+		/* refcount initialized at 1 */
+		spin_unlock_bh(&nr_node_list_lock);
+
+		nr_neigh_put(nr_neigh);
+		return 0;
+	}
+	nr_node_lock(nr_node);
+
+	if (quality != 0)
+		strcpy(nr_node->mnemonic, mnemonic);
+
+	for (found = 0, i = 0; i < nr_node->count; i++) {
+		if (nr_node->routes[i].neighbour == nr_neigh) {
+			nr_node->routes[i].quality   = quality;
+			nr_node->routes[i].obs_count = obs_count;
+			found = 1;
+			break;
+		}
+	}
+
+	if (!found) {
+		/* We have space at the bottom, slot it in */
+		if (nr_node->count < 3) {
+			nr_node->routes[2] = nr_node->routes[1];
+			nr_node->routes[1] = nr_node->routes[0];
+
+			nr_node->routes[0].quality   = quality;
+			nr_node->routes[0].obs_count = obs_count;
+			nr_node->routes[0].neighbour = nr_neigh;
+
+			nr_node->which++;
+			nr_node->count++;
+			nr_neigh_hold(nr_neigh);
+			nr_neigh->count++;
+		} else {
+			/* It must be better than the worst */
+			if (quality > nr_node->routes[2].quality) {
+				nr_node->routes[2].neighbour->count--;
+				nr_neigh_put(nr_node->routes[2].neighbour);
+
+				if (nr_node->routes[2].neighbour->count == 0 && !nr_node->routes[2].neighbour->locked)
+					nr_remove_neigh(nr_node->routes[2].neighbour);
+
+				nr_node->routes[2].quality   = quality;
+				nr_node->routes[2].obs_count = obs_count;
+				nr_node->routes[2].neighbour = nr_neigh;
+
+				nr_neigh_hold(nr_neigh);
+				nr_neigh->count++;
+			}
+		}
+	}
+
+	/* Now re-sort the routes in quality order */
+	switch (nr_node->count) {
+	case 3:
+		re_sort_routes(nr_node, 0, 1);
+		re_sort_routes(nr_node, 1, 2);
+		fallthrough;
+	case 2:
+		re_sort_routes(nr_node, 0, 1);
+		break;
+	case 1:
+		break;
+	}
+
+	for (i = 0; i < nr_node->count; i++) {
+		if (nr_node->routes[i].neighbour == nr_neigh) {
+			if (i < nr_node->which)
+				nr_node->which = i;
+			break;
+		}
+	}
+
+	nr_neigh_put(nr_neigh);
+	nr_node_unlock(nr_node);
+	nr_node_put(nr_node);
+	return 0;
+}
+
+static inline void __nr_remove_node(struct nr_node *nr_node)
+{
+	hlist_del_init(&nr_node->node_node);
+	nr_node_put(nr_node);
+}
+
+#define nr_remove_node_locked(__node) \
+	__nr_remove_node(__node)
+
+static void nr_remove_node(struct nr_node *nr_node)
+{
+	spin_lock_bh(&nr_node_list_lock);
+	__nr_remove_node(nr_node);
+	spin_unlock_bh(&nr_node_list_lock);
+}
+
+static inline void __nr_remove_neigh(struct nr_neigh *nr_neigh)
+{
+	hlist_del_init(&nr_neigh->neigh_node);
+	nr_neigh_put(nr_neigh);
+}
+
+#define nr_remove_neigh_locked(__neigh) \
+	__nr_remove_neigh(__neigh)
+
+static void nr_remove_neigh(struct nr_neigh *nr_neigh)
+{
+	spin_lock_bh(&nr_neigh_list_lock);
+	__nr_remove_neigh(nr_neigh);
+	spin_unlock_bh(&nr_neigh_list_lock);
+}
+
+/*
+ *	"Delete" a node. Strictly speaking remove a route to a node. The node
+ *	is only deleted if no routes are left to it.
+ */
+static int nr_del_node(ax25_address *callsign, ax25_address *neighbour, struct net_device *dev)
+{
+	struct nr_node  *nr_node;
+	struct nr_neigh *nr_neigh;
+	int i;
+
+	nr_node = nr_node_get(callsign);
+
+	if (nr_node == NULL)
+		return -EINVAL;
+
+	nr_neigh = nr_neigh_get_dev(neighbour, dev);
+
+	if (nr_neigh == NULL) {
+		nr_node_put(nr_node);
+		return -EINVAL;
+	}
+
+	nr_node_lock(nr_node);
+	for (i = 0; i < nr_node->count; i++) {
+		if (nr_node->routes[i].neighbour == nr_neigh) {
+			nr_neigh->count--;
+			nr_neigh_put(nr_neigh);
+
+			if (nr_neigh->count == 0 && !nr_neigh->locked)
+				nr_remove_neigh(nr_neigh);
+			nr_neigh_put(nr_neigh);
+
+			nr_node->count--;
+
+			if (nr_node->count == 0) {
+				nr_remove_node(nr_node);
+			} else {
+				switch (i) {
+				case 0:
+					nr_node->routes[0] = nr_node->routes[1];
+					fallthrough;
+				case 1:
+					nr_node->routes[1] = nr_node->routes[2];
+					fallthrough;
+				case 2:
+					break;
+				}
+				nr_node_put(nr_node);
+			}
+			nr_node_unlock(nr_node);
+
+			return 0;
+		}
+	}
+	nr_neigh_put(nr_neigh);
+	nr_node_unlock(nr_node);
+	nr_node_put(nr_node);
+
+	return -EINVAL;
+}
+
+/*
+ *	Lock a neighbour with a quality.
+ */
+static int __must_check nr_add_neigh(ax25_address *callsign,
+	ax25_digi *ax25_digi, struct net_device *dev, unsigned int quality)
+{
+	struct nr_neigh *nr_neigh;
+
+	nr_neigh = nr_neigh_get_dev(callsign, dev);
+	if (nr_neigh) {
+		nr_neigh->quality = quality;
+		nr_neigh->locked  = 1;
+		nr_neigh_put(nr_neigh);
+		return 0;
+	}
+
+	if ((nr_neigh = kmalloc(sizeof(*nr_neigh), GFP_ATOMIC)) == NULL)
+		return -ENOMEM;
+
+	nr_neigh->callsign = *callsign;
+	nr_neigh->digipeat = NULL;
+	nr_neigh->ax25     = NULL;
+	nr_neigh->dev      = dev;
+	nr_neigh->quality  = quality;
+	nr_neigh->locked   = 1;
+	nr_neigh->count    = 0;
+	nr_neigh->number   = nr_neigh_no++;
+	nr_neigh->failed   = 0;
+	refcount_set(&nr_neigh->refcount, 1);
+
+	if (ax25_digi != NULL && ax25_digi->ndigi > 0) {
+		nr_neigh->digipeat = kmemdup(ax25_digi, sizeof(*ax25_digi),
+					     GFP_KERNEL);
+		if (nr_neigh->digipeat == NULL) {
+			kfree(nr_neigh);
+			return -ENOMEM;
+		}
+	}
+
+	spin_lock_bh(&nr_neigh_list_lock);
+	hlist_add_head(&nr_neigh->neigh_node, &nr_neigh_list);
+	/* refcount is initialized at 1 */
+	spin_unlock_bh(&nr_neigh_list_lock);
+
+	return 0;
+}
+
+/*
+ *	"Delete" a neighbour. The neighbour is only removed if the number
+ *	of nodes that may use it is zero.
+ */
+static int nr_del_neigh(ax25_address *callsign, struct net_device *dev, unsigned int quality)
+{
+	struct nr_neigh *nr_neigh;
+
+	nr_neigh = nr_neigh_get_dev(callsign, dev);
+
+	if (nr_neigh == NULL) return -EINVAL;
+
+	nr_neigh->quality = quality;
+	nr_neigh->locked  = 0;
+
+	if (nr_neigh->count == 0)
+		nr_remove_neigh(nr_neigh);
+	nr_neigh_put(nr_neigh);
+
+	return 0;
+}
+
+/*
+ *	Decrement the obsolescence count by one. If a route is reduced to a
+ *	count of zero, remove it. Also remove any unlocked neighbours with
+ *	zero nodes routing via it.
+ */
+static int nr_dec_obs(void)
+{
+	struct nr_neigh *nr_neigh;
+	struct nr_node  *s;
+	struct hlist_node *nodet;
+	int i;
+
+	spin_lock_bh(&nr_node_list_lock);
+	nr_node_for_each_safe(s, nodet, &nr_node_list) {
+		nr_node_lock(s);
+		for (i = 0; i < s->count; i++) {
+			switch (s->routes[i].obs_count) {
+			case 0:		/* A locked entry */
+				break;
+
+			case 1:		/* From 1 -> 0 */
+				nr_neigh = s->routes[i].neighbour;
+
+				nr_neigh->count--;
+				nr_neigh_put(nr_neigh);
+
+				if (nr_neigh->count == 0 && !nr_neigh->locked)
+					nr_remove_neigh(nr_neigh);
+
+				s->count--;
+
+				switch (i) {
+				case 0:
+					s->routes[0] = s->routes[1];
+					fallthrough;
+				case 1:
+					s->routes[1] = s->routes[2];
+					break;
+				case 2:
+					break;
+				}
+				break;
+
+			default:
+				s->routes[i].obs_count--;
+				break;
+
+			}
+		}
+
+		if (s->count <= 0)
+			nr_remove_node_locked(s);
+		nr_node_unlock(s);
+	}
+	spin_unlock_bh(&nr_node_list_lock);
+
+	return 0;
+}
+
+/*
+ *	A device has been removed. Remove its routes and neighbours.
+ */
+void nr_rt_device_down(struct net_device *dev)
+{
+	struct nr_neigh *s;
+	struct hlist_node *nodet, *node2t;
+	struct nr_node  *t;
+	int i;
+
+	spin_lock_bh(&nr_neigh_list_lock);
+	nr_neigh_for_each_safe(s, nodet, &nr_neigh_list) {
+		if (s->dev == dev) {
+			spin_lock_bh(&nr_node_list_lock);
+			nr_node_for_each_safe(t, node2t, &nr_node_list) {
+				nr_node_lock(t);
+				for (i = 0; i < t->count; i++) {
+					if (t->routes[i].neighbour == s) {
+						t->count--;
+
+						switch (i) {
+						case 0:
+							t->routes[0] = t->routes[1];
+							fallthrough;
+						case 1:
+							t->routes[1] = t->routes[2];
+							break;
+						case 2:
+							break;
+						}
+					}
+				}
+
+				if (t->count <= 0)
+					nr_remove_node_locked(t);
+				nr_node_unlock(t);
+			}
+			spin_unlock_bh(&nr_node_list_lock);
+
+			nr_remove_neigh_locked(s);
+		}
+	}
+	spin_unlock_bh(&nr_neigh_list_lock);
+}
+
+/*
+ *	Check that the device given is a valid AX.25 interface that is "up".
+ *	Or a valid ethernet interface with an AX.25 callsign binding.
+ */
+static struct net_device *nr_ax25_dev_get(char *devname)
+{
+	struct net_device *dev;
+
+	if ((dev = dev_get_by_name(&init_net, devname)) == NULL)
+		return NULL;
+
+	if ((dev->flags & IFF_UP) && dev->type == ARPHRD_AX25)
+		return dev;
+
+	dev_put(dev);
+	return NULL;
+}
+
+/*
+ *	Find the first active NET/ROM device, usually "nr0".
+ */
+struct net_device *nr_dev_first(void)
+{
+	struct net_device *dev, *first = NULL;
+
+	rcu_read_lock();
+	for_each_netdev_rcu(&init_net, dev) {
+		if ((dev->flags & IFF_UP) && dev->type == ARPHRD_NETROM)
+			if (first == NULL || strncmp(dev->name, first->name, 3) < 0)
+				first = dev;
+	}
+	dev_hold(first);
+	rcu_read_unlock();
+
+	return first;
+}
+
+/*
+ *	Find the NET/ROM device for the given callsign.
+ */
+struct net_device *nr_dev_get(ax25_address *addr)
+{
+	struct net_device *dev;
+
+	rcu_read_lock();
+	for_each_netdev_rcu(&init_net, dev) {
+		if ((dev->flags & IFF_UP) && dev->type == ARPHRD_NETROM &&
+		    ax25cmp(addr, (const ax25_address *)dev->dev_addr) == 0) {
+			dev_hold(dev);
+			goto out;
+		}
+	}
+	dev = NULL;
+out:
+	rcu_read_unlock();
+	return dev;
+}
+
+static ax25_digi *nr_call_to_digi(ax25_digi *digi, int ndigis,
+	ax25_address *digipeaters)
+{
+	int i;
+
+	if (ndigis == 0)
+		return NULL;
+
+	for (i = 0; i < ndigis; i++) {
+		digi->calls[i]    = digipeaters[i];
+		digi->repeated[i] = 0;
+	}
+
+	digi->ndigi      = ndigis;
+	digi->lastrepeat = -1;
+
+	return digi;
+}
+
+/*
+ *	Handle the ioctls that control the routing functions.
+ */
+int nr_rt_ioctl(unsigned int cmd, void __user *arg)
+{
+	struct nr_route_struct nr_route;
+	struct net_device *dev;
+	ax25_digi digi;
+	int ret;
+
+	switch (cmd) {
+	case SIOCADDRT:
+		if (copy_from_user(&nr_route, arg, sizeof(struct nr_route_struct)))
+			return -EFAULT;
+		if (nr_route.ndigis > AX25_MAX_DIGIS)
+			return -EINVAL;
+		if ((dev = nr_ax25_dev_get(nr_route.device)) == NULL)
+			return -EINVAL;
+		switch (nr_route.type) {
+		case NETROM_NODE:
+			if (strnlen(nr_route.mnemonic, 7) == 7) {
+				ret = -EINVAL;
+				break;
+			}
+
+			ret = nr_add_node(&nr_route.callsign,
+				nr_route.mnemonic,
+				&nr_route.neighbour,
+				nr_call_to_digi(&digi, nr_route.ndigis,
+						nr_route.digipeaters),
+				dev, nr_route.quality,
+				nr_route.obs_count);
+			break;
+		case NETROM_NEIGH:
+			ret = nr_add_neigh(&nr_route.callsign,
+				nr_call_to_digi(&digi, nr_route.ndigis,
+						nr_route.digipeaters),
+				dev, nr_route.quality);
+			break;
+		default:
+			ret = -EINVAL;
+		}
+		dev_put(dev);
+		return ret;
+
+	case SIOCDELRT:
+		if (copy_from_user(&nr_route, arg, sizeof(struct nr_route_struct)))
+			return -EFAULT;
+		if ((dev = nr_ax25_dev_get(nr_route.device)) == NULL)
+			return -EINVAL;
+		switch (nr_route.type) {
+		case NETROM_NODE:
+			ret = nr_del_node(&nr_route.callsign,
+				&nr_route.neighbour, dev);
+			break;
+		case NETROM_NEIGH:
+			ret = nr_del_neigh(&nr_route.callsign,
+				dev, nr_route.quality);
+			break;
+		default:
+			ret = -EINVAL;
+		}
+		dev_put(dev);
+		return ret;
+
+	case SIOCNRDECOBS:
+		return nr_dec_obs();
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * 	A level 2 link has timed out, therefore it appears to be a poor link,
+ *	then don't use that neighbour until it is reset.
+ */
+void nr_link_failed(ax25_cb *ax25, int reason)
+{
+	struct nr_neigh *s, *nr_neigh = NULL;
+	struct nr_node  *nr_node = NULL;
+
+	spin_lock_bh(&nr_neigh_list_lock);
+	nr_neigh_for_each(s, &nr_neigh_list) {
+		if (s->ax25 == ax25) {
+			nr_neigh_hold(s);
+			nr_neigh = s;
+			break;
+		}
+	}
+	spin_unlock_bh(&nr_neigh_list_lock);
+
+	if (nr_neigh == NULL)
+		return;
+
+	nr_neigh->ax25 = NULL;
+	ax25_cb_put(ax25);
+
+	if (++nr_neigh->failed < sysctl_netrom_link_fails_count) {
+		nr_neigh_put(nr_neigh);
+		return;
+	}
+	spin_lock_bh(&nr_node_list_lock);
+	nr_node_for_each(nr_node, &nr_node_list) {
+		nr_node_lock(nr_node);
+		if (nr_node->which < nr_node->count &&
+		    nr_node->routes[nr_node->which].neighbour == nr_neigh)
+			nr_node->which++;
+		nr_node_unlock(nr_node);
+	}
+	spin_unlock_bh(&nr_node_list_lock);
+	nr_neigh_put(nr_neigh);
+}
+
+/*
+ *	Route a frame to an appropriate AX.25 connection. A NULL ax25_cb
+ *	indicates an internally generated frame.
+ */
+int nr_route_frame(struct sk_buff *skb, ax25_cb *ax25)
+{
+	ax25_address *nr_src, *nr_dest;
+	struct nr_neigh *nr_neigh;
+	struct nr_node  *nr_node;
+	struct net_device *dev;
+	unsigned char *dptr;
+	ax25_cb *ax25s;
+	int ret;
+	struct sk_buff *skbn;
+
+
+	nr_src  = (ax25_address *)(skb->data + 0);
+	nr_dest = (ax25_address *)(skb->data + 7);
+
+	if (ax25 != NULL) {
+		ret = nr_add_node(nr_src, "", &ax25->dest_addr, ax25->digipeat,
+				  ax25->ax25_dev->dev, 0,
+				  sysctl_netrom_obsolescence_count_initialiser);
+		if (ret)
+			return ret;
+	}
+
+	if ((dev = nr_dev_get(nr_dest)) != NULL) {	/* Its for me */
+		if (ax25 == NULL)			/* Its from me */
+			ret = nr_loopback_queue(skb);
+		else
+			ret = nr_rx_frame(skb, dev);
+		dev_put(dev);
+		return ret;
+	}
+
+	if (!sysctl_netrom_routing_control && ax25 != NULL)
+		return 0;
+
+	/* Its Time-To-Live has expired */
+	if (skb->data[14] == 1) {
+		return 0;
+	}
+
+	nr_node = nr_node_get(nr_dest);
+	if (nr_node == NULL)
+		return 0;
+	nr_node_lock(nr_node);
+
+	if (nr_node->which >= nr_node->count) {
+		nr_node_unlock(nr_node);
+		nr_node_put(nr_node);
+		return 0;
+	}
+
+	nr_neigh = nr_node->routes[nr_node->which].neighbour;
+
+	if ((dev = nr_dev_first()) == NULL) {
+		nr_node_unlock(nr_node);
+		nr_node_put(nr_node);
+		return 0;
+	}
+
+	/* We are going to change the netrom headers so we should get our
+	   own skb, we also did not know until now how much header space
+	   we had to reserve... - RXQ */
+	if ((skbn=skb_copy_expand(skb, dev->hard_header_len, 0, GFP_ATOMIC)) == NULL) {
+		nr_node_unlock(nr_node);
+		nr_node_put(nr_node);
+		dev_put(dev);
+		return 0;
+	}
+	kfree_skb(skb);
+	skb=skbn;
+	skb->data[14]--;
+
+	dptr  = skb_push(skb, 1);
+	*dptr = AX25_P_NETROM;
+
+	ax25s = nr_neigh->ax25;
+	nr_neigh->ax25 = ax25_send_frame(skb, 256,
+					 (const ax25_address *)dev->dev_addr,
+					 &nr_neigh->callsign,
+					 nr_neigh->digipeat, nr_neigh->dev);
+	if (ax25s)
+		ax25_cb_put(ax25s);
+
+	dev_put(dev);
+	ret = (nr_neigh->ax25 != NULL);
+	nr_node_unlock(nr_node);
+	nr_node_put(nr_node);
+
+	return ret;
+}
+
+#ifdef CONFIG_PROC_FS
+
+static void *nr_node_start(struct seq_file *seq, loff_t *pos)
+	__acquires(&nr_node_list_lock)
+{
+	spin_lock_bh(&nr_node_list_lock);
+	return seq_hlist_start_head(&nr_node_list, *pos);
+}
+
+static void *nr_node_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	return seq_hlist_next(v, &nr_node_list, pos);
+}
+
+static void nr_node_stop(struct seq_file *seq, void *v)
+	__releases(&nr_node_list_lock)
+{
+	spin_unlock_bh(&nr_node_list_lock);
+}
+
+static int nr_node_show(struct seq_file *seq, void *v)
+{
+	char buf[11];
+	int i;
+
+	if (v == SEQ_START_TOKEN)
+		seq_puts(seq,
+			 "callsign  mnemonic w n qual obs neigh qual obs neigh qual obs neigh\n");
+	else {
+		struct nr_node *nr_node = hlist_entry(v, struct nr_node,
+						      node_node);
+
+		nr_node_lock(nr_node);
+		seq_printf(seq, "%-9s %-7s  %d %d",
+			ax2asc(buf, &nr_node->callsign),
+			(nr_node->mnemonic[0] == '\0') ? "*" : nr_node->mnemonic,
+			nr_node->which + 1,
+			nr_node->count);
+
+		for (i = 0; i < nr_node->count; i++) {
+			seq_printf(seq, "  %3d   %d %05d",
+				nr_node->routes[i].quality,
+				nr_node->routes[i].obs_count,
+				nr_node->routes[i].neighbour->number);
+		}
+		nr_node_unlock(nr_node);
+
+		seq_puts(seq, "\n");
+	}
+	return 0;
+}
+
+const struct seq_operations nr_node_seqops = {
+	.start = nr_node_start,
+	.next = nr_node_next,
+	.stop = nr_node_stop,
+	.show = nr_node_show,
+};
+
+static void *nr_neigh_start(struct seq_file *seq, loff_t *pos)
+	__acquires(&nr_neigh_list_lock)
+{
+	spin_lock_bh(&nr_neigh_list_lock);
+	return seq_hlist_start_head(&nr_neigh_list, *pos);
+}
+
+static void *nr_neigh_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	return seq_hlist_next(v, &nr_neigh_list, pos);
+}
+
+static void nr_neigh_stop(struct seq_file *seq, void *v)
+	__releases(&nr_neigh_list_lock)
+{
+	spin_unlock_bh(&nr_neigh_list_lock);
+}
+
+static int nr_neigh_show(struct seq_file *seq, void *v)
+{
+	char buf[11];
+	int i;
+
+	if (v == SEQ_START_TOKEN)
+		seq_puts(seq, "addr  callsign  dev  qual lock count failed digipeaters\n");
+	else {
+		struct nr_neigh *nr_neigh;
+
+		nr_neigh = hlist_entry(v, struct nr_neigh, neigh_node);
+		seq_printf(seq, "%05d %-9s %-4s  %3d    %d   %3d    %3d",
+			nr_neigh->number,
+			ax2asc(buf, &nr_neigh->callsign),
+			nr_neigh->dev ? nr_neigh->dev->name : "???",
+			nr_neigh->quality,
+			nr_neigh->locked,
+			nr_neigh->count,
+			nr_neigh->failed);
+
+		if (nr_neigh->digipeat != NULL) {
+			for (i = 0; i < nr_neigh->digipeat->ndigi; i++)
+				seq_printf(seq, " %s",
+					   ax2asc(buf, &nr_neigh->digipeat->calls[i]));
+		}
+
+		seq_puts(seq, "\n");
+	}
+	return 0;
+}
+
+const struct seq_operations nr_neigh_seqops = {
+	.start = nr_neigh_start,
+	.next = nr_neigh_next,
+	.stop = nr_neigh_stop,
+	.show = nr_neigh_show,
+};
+#endif
+
+/*
+ *	Free all memory associated with the nodes and routes lists.
+ */
+void nr_rt_free(void)
+{
+	struct nr_neigh *s = NULL;
+	struct nr_node  *t = NULL;
+	struct hlist_node *nodet;
+
+	spin_lock_bh(&nr_neigh_list_lock);
+	spin_lock_bh(&nr_node_list_lock);
+	nr_node_for_each_safe(t, nodet, &nr_node_list) {
+		nr_node_lock(t);
+		nr_remove_node_locked(t);
+		nr_node_unlock(t);
+	}
+	nr_neigh_for_each_safe(s, nodet, &nr_neigh_list) {
+		while(s->count) {
+			s->count--;
+			nr_neigh_put(s);
+		}
+		nr_remove_neigh_locked(s);
+	}
+	spin_unlock_bh(&nr_node_list_lock);
+	spin_unlock_bh(&nr_neigh_list_lock);
+}