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, 372 insertions, 0 deletions

diff --git a/net/llc/llc_pdu.c b/net/llc/llc_pdu.c
new file mode 100644
index 000000000..63749dde5
--- /dev/null
+++ b/net/llc/llc_pdu.c
@@ -0,0 +1,372 @@
+/*
+ * llc_pdu.c - access to PDU internals
+ *
+ * Copyright (c) 1997 by Procom Technology, Inc.
+ *		 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ * This program can be redistributed or modified under the terms of the
+ * GNU General Public License as published by the Free Software Foundation.
+ * This program is distributed without any warranty or implied warranty
+ * of merchantability or fitness for a particular purpose.
+ *
+ * See the GNU General Public License for more details.
+ */
+
+#include <linux/netdevice.h>
+#include <net/llc_pdu.h>
+
+static void llc_pdu_decode_pdu_type(struct sk_buff *skb, u8 *type);
+static u8 llc_pdu_get_pf_bit(struct llc_pdu_sn *pdu);
+
+void llc_pdu_set_cmd_rsp(struct sk_buff *skb, u8 pdu_type)
+{
+	llc_pdu_un_hdr(skb)->ssap |= pdu_type;
+}
+
+/**
+ *	llc_pdu_set_pf_bit - sets poll/final bit in LLC header
+ *	@skb: Frame to set bit in
+ *	@bit_value: poll/final bit (0 or 1).
+ *
+ *	This function sets poll/final bit in LLC header (based on type of PDU).
+ *	in I or S pdus, p/f bit is right bit of fourth byte in header. in U
+ *	pdus p/f bit is fifth bit of third byte.
+ */
+void llc_pdu_set_pf_bit(struct sk_buff *skb, u8 bit_value)
+{
+	u8 pdu_type;
+	struct llc_pdu_sn *pdu;
+
+	llc_pdu_decode_pdu_type(skb, &pdu_type);
+	pdu = llc_pdu_sn_hdr(skb);
+
+	switch (pdu_type) {
+	case LLC_PDU_TYPE_I:
+	case LLC_PDU_TYPE_S:
+		pdu->ctrl_2 = (pdu->ctrl_2 & 0xFE) | bit_value;
+		break;
+	case LLC_PDU_TYPE_U:
+		pdu->ctrl_1 |= (pdu->ctrl_1 & 0xEF) | (bit_value << 4);
+		break;
+	}
+}
+
+/**
+ *	llc_pdu_decode_pf_bit - extracs poll/final bit from LLC header
+ *	@skb: input skb that p/f bit must be extracted from it
+ *	@pf_bit: poll/final bit (0 or 1)
+ *
+ *	This function extracts poll/final bit from LLC header (based on type of
+ *	PDU). In I or S pdus, p/f bit is right bit of fourth byte in header. In
+ *	U pdus p/f bit is fifth bit of third byte.
+ */
+void llc_pdu_decode_pf_bit(struct sk_buff *skb, u8 *pf_bit)
+{
+	u8 pdu_type;
+	struct llc_pdu_sn *pdu;
+
+	llc_pdu_decode_pdu_type(skb, &pdu_type);
+	pdu = llc_pdu_sn_hdr(skb);
+
+	switch (pdu_type) {
+	case LLC_PDU_TYPE_I:
+	case LLC_PDU_TYPE_S:
+		*pf_bit = pdu->ctrl_2 & LLC_S_PF_BIT_MASK;
+		break;
+	case LLC_PDU_TYPE_U:
+		*pf_bit = (pdu->ctrl_1 & LLC_U_PF_BIT_MASK) >> 4;
+		break;
+	}
+}
+
+/**
+ *	llc_pdu_init_as_disc_cmd - Builds DISC PDU
+ *	@skb: Address of the skb to build
+ *	@p_bit: The P bit to set in the PDU
+ *
+ *	Builds a pdu frame as a DISC command.
+ */
+void llc_pdu_init_as_disc_cmd(struct sk_buff *skb, u8 p_bit)
+{
+	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
+
+	pdu->ctrl_1  = LLC_PDU_TYPE_U;
+	pdu->ctrl_1 |= LLC_2_PDU_CMD_DISC;
+	pdu->ctrl_1 |= ((p_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
+}
+
+/**
+ *	llc_pdu_init_as_i_cmd - builds I pdu
+ *	@skb: Address of the skb to build
+ *	@p_bit: The P bit to set in the PDU
+ *	@ns: The sequence number of the data PDU
+ *	@nr: The seq. number of the expected I PDU from the remote
+ *
+ *	Builds a pdu frame as an I command.
+ */
+void llc_pdu_init_as_i_cmd(struct sk_buff *skb, u8 p_bit, u8 ns, u8 nr)
+{
+	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
+
+	pdu->ctrl_1  = LLC_PDU_TYPE_I;
+	pdu->ctrl_2  = 0;
+	pdu->ctrl_2 |= (p_bit & LLC_I_PF_BIT_MASK); /* p/f bit */
+	pdu->ctrl_1 |= (ns << 1) & 0xFE;   /* set N(S) in bits 2..8 */
+	pdu->ctrl_2 |= (nr << 1) & 0xFE;   /* set N(R) in bits 10..16 */
+}
+
+/**
+ *	llc_pdu_init_as_rej_cmd - builds REJ PDU
+ *	@skb: Address of the skb to build
+ *	@p_bit: The P bit to set in the PDU
+ *	@nr: The seq. number of the expected I PDU from the remote
+ *
+ *	Builds a pdu frame as a REJ command.
+ */
+void llc_pdu_init_as_rej_cmd(struct sk_buff *skb, u8 p_bit, u8 nr)
+{
+	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
+
+	pdu->ctrl_1  = LLC_PDU_TYPE_S;
+	pdu->ctrl_1 |= LLC_2_PDU_CMD_REJ;
+	pdu->ctrl_2  = 0;
+	pdu->ctrl_2 |= p_bit & LLC_S_PF_BIT_MASK;
+	pdu->ctrl_1 &= 0x0F;    /* setting bits 5..8 to zero(reserved) */
+	pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
+}
+
+/**
+ *	llc_pdu_init_as_rnr_cmd - builds RNR pdu
+ *	@skb: Address of the skb to build
+ *	@p_bit: The P bit to set in the PDU
+ *	@nr: The seq. number of the expected I PDU from the remote
+ *
+ *	Builds a pdu frame as an RNR command.
+ */
+void llc_pdu_init_as_rnr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr)
+{
+	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
+
+	pdu->ctrl_1  = LLC_PDU_TYPE_S;
+	pdu->ctrl_1 |= LLC_2_PDU_CMD_RNR;
+	pdu->ctrl_2  = 0;
+	pdu->ctrl_2 |= p_bit & LLC_S_PF_BIT_MASK;
+	pdu->ctrl_1 &= 0x0F;    /* setting bits 5..8 to zero(reserved) */
+	pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
+}
+
+/**
+ *	llc_pdu_init_as_rr_cmd - Builds RR pdu
+ *	@skb: Address of the skb to build
+ *	@p_bit: The P bit to set in the PDU
+ *	@nr: The seq. number of the expected I PDU from the remote
+ *
+ *	Builds a pdu frame as an RR command.
+ */
+void llc_pdu_init_as_rr_cmd(struct sk_buff *skb, u8 p_bit, u8 nr)
+{
+	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
+
+	pdu->ctrl_1  = LLC_PDU_TYPE_S;
+	pdu->ctrl_1 |= LLC_2_PDU_CMD_RR;
+	pdu->ctrl_2  = p_bit & LLC_S_PF_BIT_MASK;
+	pdu->ctrl_1 &= 0x0F;    /* setting bits 5..8 to zero(reserved) */
+	pdu->ctrl_2 |= (nr << 1) & 0xFE; /* set N(R) in bits 10..16 */
+}
+
+/**
+ *	llc_pdu_init_as_sabme_cmd - builds SABME pdu
+ *	@skb: Address of the skb to build
+ *	@p_bit: The P bit to set in the PDU
+ *
+ *	Builds a pdu frame as an SABME command.
+ */
+void llc_pdu_init_as_sabme_cmd(struct sk_buff *skb, u8 p_bit)
+{
+	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
+
+	pdu->ctrl_1  = LLC_PDU_TYPE_U;
+	pdu->ctrl_1 |= LLC_2_PDU_CMD_SABME;
+	pdu->ctrl_1 |= ((p_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
+}
+
+/**
+ *	llc_pdu_init_as_dm_rsp - builds DM response pdu
+ *	@skb: Address of the skb to build
+ *	@f_bit: The F bit to set in the PDU
+ *
+ *	Builds a pdu frame as a DM response.
+ */
+void llc_pdu_init_as_dm_rsp(struct sk_buff *skb, u8 f_bit)
+{
+	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
+
+	pdu->ctrl_1  = LLC_PDU_TYPE_U;
+	pdu->ctrl_1 |= LLC_2_PDU_RSP_DM;
+	pdu->ctrl_1 |= ((f_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
+}
+
+/**
+ *	llc_pdu_init_as_frmr_rsp - builds FRMR response PDU
+ *	@skb: Address of the frame to build
+ *	@prev_pdu: The rejected PDU frame
+ *	@f_bit: The F bit to set in the PDU
+ *	@vs: tx state vari value for the data link conn at the rejecting LLC
+ *	@vr: rx state var value for the data link conn at the rejecting LLC
+ *	@vzyxw: completely described in the IEEE Std 802.2 document (Pg 55)
+ *
+ *	Builds a pdu frame as a FRMR response.
+ */
+void llc_pdu_init_as_frmr_rsp(struct sk_buff *skb, struct llc_pdu_sn *prev_pdu,
+			      u8 f_bit, u8 vs, u8 vr, u8 vzyxw)
+{
+	struct llc_frmr_info *frmr_info;
+	u8 prev_pf = 0;
+	u8 *ctrl;
+	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
+
+	pdu->ctrl_1  = LLC_PDU_TYPE_U;
+	pdu->ctrl_1 |= LLC_2_PDU_RSP_FRMR;
+	pdu->ctrl_1 |= ((f_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
+
+	frmr_info = (struct llc_frmr_info *)&pdu->ctrl_2;
+	ctrl = (u8 *)&prev_pdu->ctrl_1;
+	FRMR_INFO_SET_REJ_CNTRL(frmr_info,ctrl);
+	FRMR_INFO_SET_Vs(frmr_info, vs);
+	FRMR_INFO_SET_Vr(frmr_info, vr);
+	prev_pf = llc_pdu_get_pf_bit(prev_pdu);
+	FRMR_INFO_SET_C_R_BIT(frmr_info, prev_pf);
+	FRMR_INFO_SET_INVALID_PDU_CTRL_IND(frmr_info, vzyxw);
+	FRMR_INFO_SET_INVALID_PDU_INFO_IND(frmr_info, vzyxw);
+	FRMR_INFO_SET_PDU_INFO_2LONG_IND(frmr_info, vzyxw);
+	FRMR_INFO_SET_PDU_INVALID_Nr_IND(frmr_info, vzyxw);
+	FRMR_INFO_SET_PDU_INVALID_Ns_IND(frmr_info, vzyxw);
+	skb_put(skb, sizeof(struct llc_frmr_info));
+}
+
+/**
+ *	llc_pdu_init_as_rr_rsp - builds RR response pdu
+ *	@skb: Address of the skb to build
+ *	@f_bit: The F bit to set in the PDU
+ *	@nr: The seq. number of the expected data PDU from the remote
+ *
+ *	Builds a pdu frame as an RR response.
+ */
+void llc_pdu_init_as_rr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr)
+{
+	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
+
+	pdu->ctrl_1  = LLC_PDU_TYPE_S;
+	pdu->ctrl_1 |= LLC_2_PDU_RSP_RR;
+	pdu->ctrl_2  = 0;
+	pdu->ctrl_2 |= f_bit & LLC_S_PF_BIT_MASK;
+	pdu->ctrl_1 &= 0x0F;    /* setting bits 5..8 to zero(reserved) */
+	pdu->ctrl_2 |= (nr << 1) & 0xFE;  /* set N(R) in bits 10..16 */
+}
+
+/**
+ *	llc_pdu_init_as_rej_rsp - builds REJ response pdu
+ *	@skb: Address of the skb to build
+ *	@f_bit: The F bit to set in the PDU
+ *	@nr: The seq. number of the expected data PDU from the remote
+ *
+ *	Builds a pdu frame as a REJ response.
+ */
+void llc_pdu_init_as_rej_rsp(struct sk_buff *skb, u8 f_bit, u8 nr)
+{
+	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
+
+	pdu->ctrl_1  = LLC_PDU_TYPE_S;
+	pdu->ctrl_1 |= LLC_2_PDU_RSP_REJ;
+	pdu->ctrl_2  = 0;
+	pdu->ctrl_2 |= f_bit & LLC_S_PF_BIT_MASK;
+	pdu->ctrl_1 &= 0x0F;    /* setting bits 5..8 to zero(reserved) */
+	pdu->ctrl_2 |= (nr << 1) & 0xFE;  /* set N(R) in bits 10..16 */
+}
+
+/**
+ *	llc_pdu_init_as_rnr_rsp - builds RNR response pdu
+ *	@skb: Address of the frame to build
+ *	@f_bit: The F bit to set in the PDU
+ *	@nr: The seq. number of the expected data PDU from the remote
+ *
+ *	Builds a pdu frame as an RNR response.
+ */
+void llc_pdu_init_as_rnr_rsp(struct sk_buff *skb, u8 f_bit, u8 nr)
+{
+	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
+
+	pdu->ctrl_1  = LLC_PDU_TYPE_S;
+	pdu->ctrl_1 |= LLC_2_PDU_RSP_RNR;
+	pdu->ctrl_2  = 0;
+	pdu->ctrl_2 |= f_bit & LLC_S_PF_BIT_MASK;
+	pdu->ctrl_1 &= 0x0F;    /* setting bits 5..8 to zero(reserved) */
+	pdu->ctrl_2 |= (nr << 1) & 0xFE;  /* set N(R) in bits 10..16 */
+}
+
+/**
+ *	llc_pdu_init_as_ua_rsp - builds UA response pdu
+ *	@skb: Address of the frame to build
+ *	@f_bit: The F bit to set in the PDU
+ *
+ *	Builds a pdu frame as a UA response.
+ */
+void llc_pdu_init_as_ua_rsp(struct sk_buff *skb, u8 f_bit)
+{
+	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
+
+	pdu->ctrl_1  = LLC_PDU_TYPE_U;
+	pdu->ctrl_1 |= LLC_2_PDU_RSP_UA;
+	pdu->ctrl_1 |= ((f_bit & 1) << 4) & LLC_U_PF_BIT_MASK;
+}
+
+/**
+ *	llc_pdu_decode_pdu_type - designates PDU type
+ *	@skb: input skb that type of it must be designated.
+ *	@type: type of PDU (output argument).
+ *
+ *	This function designates type of PDU (I, S or U).
+ */
+static void llc_pdu_decode_pdu_type(struct sk_buff *skb, u8 *type)
+{
+	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
+
+	if (pdu->ctrl_1 & 1) {
+		if ((pdu->ctrl_1 & LLC_PDU_TYPE_U) == LLC_PDU_TYPE_U)
+			*type = LLC_PDU_TYPE_U;
+		else
+			*type = LLC_PDU_TYPE_S;
+	} else
+		*type = LLC_PDU_TYPE_I;
+}
+
+/**
+ *	llc_pdu_get_pf_bit - extracts p/f bit of input PDU
+ *	@pdu: pointer to LLC header.
+ *
+ *	This function extracts p/f bit of input PDU. at first examines type of
+ *	PDU and then extracts p/f bit. Returns the p/f bit.
+ */
+static u8 llc_pdu_get_pf_bit(struct llc_pdu_sn *pdu)
+{
+	u8 pdu_type;
+	u8 pf_bit = 0;
+
+	if (pdu->ctrl_1 & 1) {
+		if ((pdu->ctrl_1 & LLC_PDU_TYPE_U) == LLC_PDU_TYPE_U)
+			pdu_type = LLC_PDU_TYPE_U;
+		else
+			pdu_type = LLC_PDU_TYPE_S;
+	} else
+		pdu_type = LLC_PDU_TYPE_I;
+	switch (pdu_type) {
+	case LLC_PDU_TYPE_I:
+	case LLC_PDU_TYPE_S:
+		pf_bit = pdu->ctrl_2 & LLC_S_PF_BIT_MASK;
+		break;
+	case LLC_PDU_TYPE_U:
+		pf_bit = (pdu->ctrl_1 & LLC_U_PF_BIT_MASK) >> 4;
+		break;
+	}
+	return pf_bit;
+}