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, 635 insertions, 0 deletions

diff --git a/drivers/net/ppp/ppp_deflate.c b/drivers/net/ppp/ppp_deflate.c
new file mode 100644
index 000000000..e6d48e5c6
--- /dev/null
+++ b/drivers/net/ppp/ppp_deflate.c
@@ -0,0 +1,635 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ppp_deflate.c - interface the zlib procedures for Deflate compression
+ * and decompression (as used by gzip) to the PPP code.
+ *
+ * Copyright 1994-1998 Paul Mackerras.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+#include <linux/string.h>
+
+#include <linux/ppp_defs.h>
+#include <linux/ppp-comp.h>
+
+#include <linux/zlib.h>
+#include <asm/unaligned.h>
+
+/*
+ * State for a Deflate (de)compressor.
+ */
+struct ppp_deflate_state {
+    int		seqno;
+    int		w_size;
+    int		unit;
+    int		mru;
+    int		debug;
+    z_stream	strm;
+    struct compstat stats;
+};
+
+#define DEFLATE_OVHD	2		/* Deflate overhead/packet */
+
+static void	*z_comp_alloc(unsigned char *options, int opt_len);
+static void	*z_decomp_alloc(unsigned char *options, int opt_len);
+static void	z_comp_free(void *state);
+static void	z_decomp_free(void *state);
+static int	z_comp_init(void *state, unsigned char *options,
+				 int opt_len,
+				 int unit, int hdrlen, int debug);
+static int	z_decomp_init(void *state, unsigned char *options,
+				   int opt_len,
+				   int unit, int hdrlen, int mru, int debug);
+static int	z_compress(void *state, unsigned char *rptr,
+				unsigned char *obuf,
+				int isize, int osize);
+static void	z_incomp(void *state, unsigned char *ibuf, int icnt);
+static int	z_decompress(void *state, unsigned char *ibuf,
+				int isize, unsigned char *obuf, int osize);
+static void	z_comp_reset(void *state);
+static void	z_decomp_reset(void *state);
+static void	z_comp_stats(void *state, struct compstat *stats);
+
+/**
+ *	z_comp_free - free the memory used by a compressor
+ *	@arg:	pointer to the private state for the compressor.
+ */
+static void z_comp_free(void *arg)
+{
+	struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+
+	if (state) {
+		zlib_deflateEnd(&state->strm);
+		vfree(state->strm.workspace);
+		kfree(state);
+	}
+}
+
+/**
+ *	z_comp_alloc - allocate space for a compressor.
+ *	@options: pointer to CCP option data
+ *	@opt_len: length of the CCP option at @options.
+ *
+ *	The @options pointer points to the a buffer containing the
+ *	CCP option data for the compression being negotiated.  It is
+ *	formatted according to RFC1979, and describes the window
+ *	size that the peer is requesting that we use in compressing
+ *	data to be sent to it.
+ *
+ *	Returns the pointer to the private state for the compressor,
+ *	or NULL if we could not allocate enough memory.
+ */
+static void *z_comp_alloc(unsigned char *options, int opt_len)
+{
+	struct ppp_deflate_state *state;
+	int w_size;
+
+	if (opt_len != CILEN_DEFLATE ||
+	    (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
+	    options[1] != CILEN_DEFLATE ||
+	    DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
+	    options[3] != DEFLATE_CHK_SEQUENCE)
+		return NULL;
+	w_size = DEFLATE_SIZE(options[2]);
+	if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
+		return NULL;
+
+	state = kzalloc(sizeof(*state),
+						     GFP_KERNEL);
+	if (state == NULL)
+		return NULL;
+
+	state->strm.next_in   = NULL;
+	state->w_size         = w_size;
+	state->strm.workspace = vmalloc(zlib_deflate_workspacesize(-w_size, 8));
+	if (state->strm.workspace == NULL)
+		goto out_free;
+
+	if (zlib_deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION,
+			 DEFLATE_METHOD_VAL, -w_size, 8, Z_DEFAULT_STRATEGY)
+	    != Z_OK)
+		goto out_free;
+	return (void *) state;
+
+out_free:
+	z_comp_free(state);
+	return NULL;
+}
+
+/**
+ *	z_comp_init - initialize a previously-allocated compressor.
+ *	@arg:	pointer to the private state for the compressor
+ *	@options: pointer to the CCP option data describing the
+ *		compression that was negotiated with the peer
+ *	@opt_len: length of the CCP option data at @options
+ *	@unit:	PPP unit number for diagnostic messages
+ *	@hdrlen: ignored (present for backwards compatibility)
+ *	@debug:	debug flag; if non-zero, debug messages are printed.
+ *
+ *	The CCP options described by @options must match the options
+ *	specified when the compressor was allocated.  The compressor
+ *	history is reset.  Returns 0 for failure (CCP options don't
+ *	match) or 1 for success.
+ */
+static int z_comp_init(void *arg, unsigned char *options, int opt_len,
+		       int unit, int hdrlen, int debug)
+{
+	struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+
+	if (opt_len < CILEN_DEFLATE ||
+	    (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
+	    options[1] != CILEN_DEFLATE ||
+	    DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
+	    DEFLATE_SIZE(options[2]) != state->w_size ||
+	    options[3] != DEFLATE_CHK_SEQUENCE)
+		return 0;
+
+	state->seqno = 0;
+	state->unit  = unit;
+	state->debug = debug;
+
+	zlib_deflateReset(&state->strm);
+
+	return 1;
+}
+
+/**
+ *	z_comp_reset - reset a previously-allocated compressor.
+ *	@arg:	pointer to private state for the compressor.
+ *
+ *	This clears the history for the compressor and makes it
+ *	ready to start emitting a new compressed stream.
+ */
+static void z_comp_reset(void *arg)
+{
+	struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+
+	state->seqno = 0;
+	zlib_deflateReset(&state->strm);
+}
+
+/**
+ *	z_compress - compress a PPP packet with Deflate compression.
+ *	@arg:	pointer to private state for the compressor
+ *	@rptr:	uncompressed packet (input)
+ *	@obuf:	compressed packet (output)
+ *	@isize:	size of uncompressed packet
+ *	@osize:	space available at @obuf
+ *
+ *	Returns the length of the compressed packet, or 0 if the
+ *	packet is incompressible.
+ */
+static int z_compress(void *arg, unsigned char *rptr, unsigned char *obuf,
+	       int isize, int osize)
+{
+	struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+	int r, proto, off, olen, oavail;
+	unsigned char *wptr;
+
+	/*
+	 * Check that the protocol is in the range we handle.
+	 */
+	proto = PPP_PROTOCOL(rptr);
+	if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
+		return 0;
+
+	/* Don't generate compressed packets which are larger than
+	   the uncompressed packet. */
+	if (osize > isize)
+		osize = isize;
+
+	wptr = obuf;
+
+	/*
+	 * Copy over the PPP header and store the 2-byte sequence number.
+	 */
+	wptr[0] = PPP_ADDRESS(rptr);
+	wptr[1] = PPP_CONTROL(rptr);
+	put_unaligned_be16(PPP_COMP, wptr + 2);
+	wptr += PPP_HDRLEN;
+	put_unaligned_be16(state->seqno, wptr);
+	wptr += DEFLATE_OVHD;
+	olen = PPP_HDRLEN + DEFLATE_OVHD;
+	state->strm.next_out = wptr;
+	state->strm.avail_out = oavail = osize - olen;
+	++state->seqno;
+
+	off = (proto > 0xff) ? 2 : 3;	/* skip 1st proto byte if 0 */
+	rptr += off;
+	state->strm.next_in = rptr;
+	state->strm.avail_in = (isize - off);
+
+	for (;;) {
+		r = zlib_deflate(&state->strm, Z_PACKET_FLUSH);
+		if (r != Z_OK) {
+			if (state->debug)
+				printk(KERN_ERR
+				       "z_compress: deflate returned %d\n", r);
+			break;
+		}
+		if (state->strm.avail_out == 0) {
+			olen += oavail;
+			state->strm.next_out = NULL;
+			state->strm.avail_out = oavail = 1000000;
+		} else {
+			break;		/* all done */
+		}
+	}
+	olen += oavail - state->strm.avail_out;
+
+	/*
+	 * See if we managed to reduce the size of the packet.
+	 */
+	if (olen < isize && olen <= osize) {
+		state->stats.comp_bytes += olen;
+		state->stats.comp_packets++;
+	} else {
+		state->stats.inc_bytes += isize;
+		state->stats.inc_packets++;
+		olen = 0;
+	}
+	state->stats.unc_bytes += isize;
+	state->stats.unc_packets++;
+
+	return olen;
+}
+
+/**
+ *	z_comp_stats - return compression statistics for a compressor
+ *		or decompressor.
+ *	@arg:	pointer to private space for the (de)compressor
+ *	@stats:	pointer to a struct compstat to receive the result.
+ */
+static void z_comp_stats(void *arg, struct compstat *stats)
+{
+	struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+
+	*stats = state->stats;
+}
+
+/**
+ *	z_decomp_free - Free the memory used by a decompressor.
+ *	@arg:	pointer to private space for the decompressor.
+ */
+static void z_decomp_free(void *arg)
+{
+	struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+
+	if (state) {
+		vfree(state->strm.workspace);
+		kfree(state);
+	}
+}
+
+/**
+ *	z_decomp_alloc - allocate space for a decompressor.
+ *	@options: pointer to CCP option data
+ *	@opt_len: length of the CCP option at @options.
+ *
+ *	The @options pointer points to the a buffer containing the
+ *	CCP option data for the compression being negotiated.  It is
+ *	formatted according to RFC1979, and describes the window
+ *	size that we are requesting the peer to use in compressing
+ *	data to be sent to us.
+ *
+ *	Returns the pointer to the private state for the decompressor,
+ *	or NULL if we could not allocate enough memory.
+ */
+static void *z_decomp_alloc(unsigned char *options, int opt_len)
+{
+	struct ppp_deflate_state *state;
+	int w_size;
+
+	if (opt_len != CILEN_DEFLATE ||
+	    (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
+	    options[1] != CILEN_DEFLATE ||
+	    DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
+	    options[3] != DEFLATE_CHK_SEQUENCE)
+		return NULL;
+	w_size = DEFLATE_SIZE(options[2]);
+	if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
+		return NULL;
+
+	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	if (state == NULL)
+		return NULL;
+
+	state->w_size         = w_size;
+	state->strm.next_out  = NULL;
+	state->strm.workspace = vmalloc(zlib_inflate_workspacesize());
+	if (state->strm.workspace == NULL)
+		goto out_free;
+
+	if (zlib_inflateInit2(&state->strm, -w_size) != Z_OK)
+		goto out_free;
+	return (void *) state;
+
+out_free:
+	z_decomp_free(state);
+	return NULL;
+}
+
+/**
+ *	z_decomp_init - initialize a previously-allocated decompressor.
+ *	@arg:	pointer to the private state for the decompressor
+ *	@options: pointer to the CCP option data describing the
+ *		compression that was negotiated with the peer
+ *	@opt_len: length of the CCP option data at @options
+ *	@unit:	PPP unit number for diagnostic messages
+ *	@hdrlen: ignored (present for backwards compatibility)
+ *	@mru:	maximum length of decompressed packets
+ *	@debug:	debug flag; if non-zero, debug messages are printed.
+ *
+ *	The CCP options described by @options must match the options
+ *	specified when the decompressor was allocated.  The decompressor
+ *	history is reset.  Returns 0 for failure (CCP options don't
+ *	match) or 1 for success.
+ */
+static int z_decomp_init(void *arg, unsigned char *options, int opt_len,
+			 int unit, int hdrlen, int mru, int debug)
+{
+	struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+
+	if (opt_len < CILEN_DEFLATE ||
+	    (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
+	    options[1] != CILEN_DEFLATE ||
+	    DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
+	    DEFLATE_SIZE(options[2]) != state->w_size ||
+	    options[3] != DEFLATE_CHK_SEQUENCE)
+		return 0;
+
+	state->seqno = 0;
+	state->unit  = unit;
+	state->debug = debug;
+	state->mru   = mru;
+
+	zlib_inflateReset(&state->strm);
+
+	return 1;
+}
+
+/**
+ *	z_decomp_reset - reset a previously-allocated decompressor.
+ *	@arg:	pointer to private state for the decompressor.
+ *
+ *	This clears the history for the decompressor and makes it
+ *	ready to receive a new compressed stream.
+ */
+static void z_decomp_reset(void *arg)
+{
+	struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+
+	state->seqno = 0;
+	zlib_inflateReset(&state->strm);
+}
+
+/**
+ *	z_decompress - decompress a Deflate-compressed packet.
+ *	@arg:	pointer to private state for the decompressor
+ *	@ibuf:	pointer to input (compressed) packet data
+ *	@isize:	length of input packet
+ *	@obuf:	pointer to space for output (decompressed) packet
+ *	@osize:	amount of space available at @obuf
+ *
+ * Because of patent problems, we return DECOMP_ERROR for errors
+ * found by inspecting the input data and for system problems, but
+ * DECOMP_FATALERROR for any errors which could possibly be said to
+ * be being detected "after" decompression.  For DECOMP_ERROR,
+ * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
+ * infringing a patent of Motorola's if we do, so we take CCP down
+ * instead.
+ *
+ * Given that the frame has the correct sequence number and a good FCS,
+ * errors such as invalid codes in the input most likely indicate a
+ * bug, so we return DECOMP_FATALERROR for them in order to turn off
+ * compression, even though they are detected by inspecting the input.
+ */
+static int z_decompress(void *arg, unsigned char *ibuf, int isize,
+		 unsigned char *obuf, int osize)
+{
+	struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+	int olen, seq, r;
+	int decode_proto, overflow;
+	unsigned char overflow_buf[1];
+
+	if (isize <= PPP_HDRLEN + DEFLATE_OVHD) {
+		if (state->debug)
+			printk(KERN_DEBUG "z_decompress%d: short pkt (%d)\n",
+			       state->unit, isize);
+		return DECOMP_ERROR;
+	}
+
+	/* Check the sequence number. */
+	seq = get_unaligned_be16(ibuf + PPP_HDRLEN);
+	if (seq != (state->seqno & 0xffff)) {
+		if (state->debug)
+			printk(KERN_DEBUG "z_decompress%d: bad seq # %d, expected %d\n",
+			       state->unit, seq, state->seqno & 0xffff);
+		return DECOMP_ERROR;
+	}
+	++state->seqno;
+
+	/*
+	 * Fill in the first part of the PPP header.  The protocol field
+	 * comes from the decompressed data.
+	 */
+	obuf[0] = PPP_ADDRESS(ibuf);
+	obuf[1] = PPP_CONTROL(ibuf);
+	obuf[2] = 0;
+
+	/*
+	 * Set up to call inflate.  We set avail_out to 1 initially so we can
+	 * look at the first byte of the output and decide whether we have
+	 * a 1-byte or 2-byte protocol field.
+	 */
+	state->strm.next_in = ibuf + PPP_HDRLEN + DEFLATE_OVHD;
+	state->strm.avail_in = isize - (PPP_HDRLEN + DEFLATE_OVHD);
+	state->strm.next_out = obuf + 3;
+	state->strm.avail_out = 1;
+	decode_proto = 1;
+	overflow = 0;
+
+	/*
+	 * Call inflate, supplying more input or output as needed.
+	 */
+	for (;;) {
+		r = zlib_inflate(&state->strm, Z_PACKET_FLUSH);
+		if (r != Z_OK) {
+			if (state->debug)
+				printk(KERN_DEBUG "z_decompress%d: inflate returned %d (%s)\n",
+				       state->unit, r, (state->strm.msg? state->strm.msg: ""));
+			return DECOMP_FATALERROR;
+		}
+		if (state->strm.avail_out != 0)
+			break;		/* all done */
+		if (decode_proto) {
+			state->strm.avail_out = osize - PPP_HDRLEN;
+			if ((obuf[3] & 1) == 0) {
+				/* 2-byte protocol field */
+				obuf[2] = obuf[3];
+				--state->strm.next_out;
+				++state->strm.avail_out;
+			}
+			decode_proto = 0;
+		} else if (!overflow) {
+			/*
+			 * We've filled up the output buffer; the only way to
+			 * find out whether inflate has any more characters
+			 * left is to give it another byte of output space.
+			 */
+			state->strm.next_out = overflow_buf;
+			state->strm.avail_out = 1;
+			overflow = 1;
+		} else {
+			if (state->debug)
+				printk(KERN_DEBUG "z_decompress%d: ran out of mru\n",
+				       state->unit);
+			return DECOMP_FATALERROR;
+		}
+	}
+
+	if (decode_proto) {
+		if (state->debug)
+			printk(KERN_DEBUG "z_decompress%d: didn't get proto\n",
+			       state->unit);
+		return DECOMP_ERROR;
+	}
+
+	olen = osize + overflow - state->strm.avail_out;
+	state->stats.unc_bytes += olen;
+	state->stats.unc_packets++;
+	state->stats.comp_bytes += isize;
+	state->stats.comp_packets++;
+
+	return olen;
+}
+
+/**
+ *	z_incomp - add incompressible input data to the history.
+ *	@arg:	pointer to private state for the decompressor
+ *	@ibuf:	pointer to input packet data
+ *	@icnt:	length of input data.
+ */
+static void z_incomp(void *arg, unsigned char *ibuf, int icnt)
+{
+	struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+	int proto, r;
+
+	/*
+	 * Check that the protocol is one we handle.
+	 */
+	proto = PPP_PROTOCOL(ibuf);
+	if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
+		return;
+
+	++state->seqno;
+
+	/*
+	 * We start at the either the 1st or 2nd byte of the protocol field,
+	 * depending on whether the protocol value is compressible.
+	 */
+	state->strm.next_in = ibuf + 3;
+	state->strm.avail_in = icnt - 3;
+	if (proto > 0xff) {
+		--state->strm.next_in;
+		++state->strm.avail_in;
+	}
+
+	r = zlib_inflateIncomp(&state->strm);
+	if (r != Z_OK) {
+		/* gak! */
+		if (state->debug) {
+			printk(KERN_DEBUG "z_incomp%d: inflateIncomp returned %d (%s)\n",
+			       state->unit, r, (state->strm.msg? state->strm.msg: ""));
+		}
+		return;
+	}
+
+	/*
+	 * Update stats.
+	 */
+	state->stats.inc_bytes += icnt;
+	state->stats.inc_packets++;
+	state->stats.unc_bytes += icnt;
+	state->stats.unc_packets++;
+}
+
+/*************************************************************
+ * Module interface table
+ *************************************************************/
+
+/* These are in ppp_generic.c */
+extern int  ppp_register_compressor   (struct compressor *cp);
+extern void ppp_unregister_compressor (struct compressor *cp);
+
+/*
+ * Procedures exported to if_ppp.c.
+ */
+static struct compressor ppp_deflate = {
+	.compress_proto =	CI_DEFLATE,
+	.comp_alloc =		z_comp_alloc,
+	.comp_free =		z_comp_free,
+	.comp_init =		z_comp_init,
+	.comp_reset =		z_comp_reset,
+	.compress =		z_compress,
+	.comp_stat =		z_comp_stats,
+	.decomp_alloc =		z_decomp_alloc,
+	.decomp_free =		z_decomp_free,
+	.decomp_init =		z_decomp_init,
+	.decomp_reset =		z_decomp_reset,
+	.decompress =		z_decompress,
+	.incomp =		z_incomp,
+	.decomp_stat =		z_comp_stats,
+	.owner =		THIS_MODULE
+};
+
+static struct compressor ppp_deflate_draft = {
+	.compress_proto =	CI_DEFLATE_DRAFT,
+	.comp_alloc =		z_comp_alloc,
+	.comp_free =		z_comp_free,
+	.comp_init =		z_comp_init,
+	.comp_reset =		z_comp_reset,
+	.compress =		z_compress,
+	.comp_stat =		z_comp_stats,
+	.decomp_alloc =		z_decomp_alloc,
+	.decomp_free =		z_decomp_free,
+	.decomp_init =		z_decomp_init,
+	.decomp_reset =		z_decomp_reset,
+	.decompress =		z_decompress,
+	.incomp =		z_incomp,
+	.decomp_stat =		z_comp_stats,
+	.owner =		THIS_MODULE
+};
+
+static int __init deflate_init(void)
+{
+	int rc;
+
+	rc = ppp_register_compressor(&ppp_deflate);
+	if (rc)
+		return rc;
+
+	rc = ppp_register_compressor(&ppp_deflate_draft);
+	if (rc) {
+		ppp_unregister_compressor(&ppp_deflate);
+		return rc;
+	}
+
+	pr_info("PPP Deflate Compression module registered\n");
+	return 0;
+}
+
+static void __exit deflate_cleanup(void)
+{
+	ppp_unregister_compressor(&ppp_deflate);
+	ppp_unregister_compressor(&ppp_deflate_draft);
+}
+
+module_init(deflate_init);
+module_exit(deflate_cleanup);
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE));
+MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE_DRAFT));