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, 755 insertions, 0 deletions

diff --git a/drivers/net/slip/slhc.c b/drivers/net/slip/slhc.c
new file mode 100644
index 000000000..ba93bab94
--- /dev/null
+++ b/drivers/net/slip/slhc.c
@@ -0,0 +1,755 @@
+/*
+ * Routines to compress and uncompress tcp packets (for transmission
+ * over low speed serial lines).
+ *
+ * Copyright (c) 1989 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the University of California, Berkeley.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ *	Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
+ *	- Initial distribution.
+ *
+ *
+ * modified for KA9Q Internet Software Package by
+ * Katie Stevens (dkstevens@ucdavis.edu)
+ * University of California, Davis
+ * Computing Services
+ *	- 01-31-90	initial adaptation (from 1.19)
+ *	PPP.05	02-15-90 [ks]
+ *	PPP.08	05-02-90 [ks]	use PPP protocol field to signal compression
+ *	PPP.15	09-90	 [ks]	improve mbuf handling
+ *	PPP.16	11-02	 [karn]	substantially rewritten to use NOS facilities
+ *
+ *	- Feb 1991	Bill_Simpson@um.cc.umich.edu
+ *			variable number of conversation slots
+ *			allow zero or one slots
+ *			separate routines
+ *			status display
+ *	- Jul 1994	Dmitry Gorodchanin
+ *			Fixes for memory leaks.
+ *      - Oct 1994      Dmitry Gorodchanin
+ *                      Modularization.
+ *	- Jan 1995	Bjorn Ekwall
+ *			Use ip_fast_csum from ip.h
+ *	- July 1995	Christos A. Polyzols
+ *			Spotted bug in tcp option checking
+ *
+ *
+ *	This module is a difficult issue. It's clearly inet code but it's also clearly
+ *	driver code belonging close to PPP and SLIP
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <net/slhc_vj.h>
+
+#ifdef CONFIG_INET
+/* Entire module is for IP only */
+#include <linux/mm.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/termios.h>
+#include <linux/in.h>
+#include <linux/fcntl.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <net/ip.h>
+#include <net/protocol.h>
+#include <net/icmp.h>
+#include <net/tcp.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/timer.h>
+#include <linux/uaccess.h>
+#include <net/checksum.h>
+#include <asm/unaligned.h>
+
+static unsigned char *encode(unsigned char *cp, unsigned short n);
+static long decode(unsigned char **cpp);
+static unsigned char * put16(unsigned char *cp, unsigned short x);
+static unsigned short pull16(unsigned char **cpp);
+
+/* Allocate compression data structure
+ *	slots must be in range 0 to 255 (zero meaning no compression)
+ * Returns pointer to structure or ERR_PTR() on error.
+ */
+struct slcompress *
+slhc_init(int rslots, int tslots)
+{
+	short i;
+	struct cstate *ts;
+	struct slcompress *comp;
+
+	if (rslots < 0 || rslots > 255 || tslots < 0 || tslots > 255)
+		return ERR_PTR(-EINVAL);
+
+	comp = kzalloc(sizeof(struct slcompress), GFP_KERNEL);
+	if (! comp)
+		goto out_fail;
+
+	if (rslots > 0) {
+		size_t rsize = rslots * sizeof(struct cstate);
+		comp->rstate = kzalloc(rsize, GFP_KERNEL);
+		if (! comp->rstate)
+			goto out_free;
+		comp->rslot_limit = rslots - 1;
+	}
+
+	if (tslots > 0) {
+		size_t tsize = tslots * sizeof(struct cstate);
+		comp->tstate = kzalloc(tsize, GFP_KERNEL);
+		if (! comp->tstate)
+			goto out_free2;
+		comp->tslot_limit = tslots - 1;
+	}
+
+	comp->xmit_oldest = 0;
+	comp->xmit_current = 255;
+	comp->recv_current = 255;
+	/*
+	 * don't accept any packets with implicit index until we get
+	 * one with an explicit index.  Otherwise the uncompress code
+	 * will try to use connection 255, which is almost certainly
+	 * out of range
+	 */
+	comp->flags |= SLF_TOSS;
+
+	if ( tslots > 0 ) {
+		ts = comp->tstate;
+		for(i = comp->tslot_limit; i > 0; --i){
+			ts[i].cs_this = i;
+			ts[i].next = &(ts[i - 1]);
+		}
+		ts[0].next = &(ts[comp->tslot_limit]);
+		ts[0].cs_this = 0;
+	}
+	return comp;
+
+out_free2:
+	kfree(comp->rstate);
+out_free:
+	kfree(comp);
+out_fail:
+	return ERR_PTR(-ENOMEM);
+}
+
+
+/* Free a compression data structure */
+void
+slhc_free(struct slcompress *comp)
+{
+	if ( IS_ERR_OR_NULL(comp) )
+		return;
+
+	if ( comp->tstate != NULLSLSTATE )
+		kfree( comp->tstate );
+
+	if ( comp->rstate != NULLSLSTATE )
+		kfree( comp->rstate );
+
+	kfree( comp );
+}
+
+
+/* Put a short in host order into a char array in network order */
+static inline unsigned char *
+put16(unsigned char *cp, unsigned short x)
+{
+	*cp++ = x >> 8;
+	*cp++ = x;
+
+	return cp;
+}
+
+
+/* Encode a number */
+static unsigned char *
+encode(unsigned char *cp, unsigned short n)
+{
+	if(n >= 256 || n == 0){
+		*cp++ = 0;
+		cp = put16(cp,n);
+	} else {
+		*cp++ = n;
+	}
+	return cp;
+}
+
+/* Pull a 16-bit integer in host order from buffer in network byte order */
+static unsigned short
+pull16(unsigned char **cpp)
+{
+	short rval;
+
+	rval = *(*cpp)++;
+	rval <<= 8;
+	rval |= *(*cpp)++;
+	return rval;
+}
+
+/* Decode a number */
+static long
+decode(unsigned char **cpp)
+{
+	int x;
+
+	x = *(*cpp)++;
+	if(x == 0){
+		return pull16(cpp) & 0xffff;	/* pull16 returns -1 on error */
+	} else {
+		return x & 0xff;		/* -1 if PULLCHAR returned error */
+	}
+}
+
+/*
+ * icp and isize are the original packet.
+ * ocp is a place to put a copy if necessary.
+ * cpp is initially a pointer to icp.  If the copy is used,
+ *    change it to ocp.
+ */
+
+int
+slhc_compress(struct slcompress *comp, unsigned char *icp, int isize,
+	unsigned char *ocp, unsigned char **cpp, int compress_cid)
+{
+	struct cstate *ocs = &(comp->tstate[comp->xmit_oldest]);
+	struct cstate *lcs = ocs;
+	struct cstate *cs = lcs->next;
+	unsigned long deltaS, deltaA;
+	short changes = 0;
+	int nlen, hlen;
+	unsigned char new_seq[16];
+	unsigned char *cp = new_seq;
+	struct iphdr *ip;
+	struct tcphdr *th, *oth;
+	__sum16 csum;
+
+
+	/*
+	 *	Don't play with runt packets.
+	 */
+
+	if(isize<sizeof(struct iphdr))
+		return isize;
+
+	ip = (struct iphdr *) icp;
+	if (ip->version != 4 || ip->ihl < 5)
+		return isize;
+
+	/* Bail if this packet isn't TCP, or is an IP fragment */
+	if (ip->protocol != IPPROTO_TCP || (ntohs(ip->frag_off) & 0x3fff)) {
+		/* Send as regular IP */
+		if(ip->protocol != IPPROTO_TCP)
+			comp->sls_o_nontcp++;
+		else
+			comp->sls_o_tcp++;
+		return isize;
+	}
+	nlen = ip->ihl * 4;
+	if (isize < nlen + sizeof(*th))
+		return isize;
+
+	th = (struct tcphdr *)(icp + nlen);
+	if (th->doff < sizeof(struct tcphdr) / 4)
+		return isize;
+	hlen = nlen + th->doff * 4;
+
+	/*  Bail if the TCP packet isn't `compressible' (i.e., ACK isn't set or
+	 *  some other control bit is set). Also uncompressible if
+	 *  it's a runt.
+	 */
+	if(hlen > isize || th->syn || th->fin || th->rst ||
+	    ! (th->ack)){
+		/* TCP connection stuff; send as regular IP */
+		comp->sls_o_tcp++;
+		return isize;
+	}
+	/*
+	 * Packet is compressible -- we're going to send either a
+	 * COMPRESSED_TCP or UNCOMPRESSED_TCP packet.  Either way,
+	 * we need to locate (or create) the connection state.
+	 *
+	 * States are kept in a circularly linked list with
+	 * xmit_oldest pointing to the end of the list.  The
+	 * list is kept in lru order by moving a state to the
+	 * head of the list whenever it is referenced.  Since
+	 * the list is short and, empirically, the connection
+	 * we want is almost always near the front, we locate
+	 * states via linear search.  If we don't find a state
+	 * for the datagram, the oldest state is (re-)used.
+	 */
+	for ( ; ; ) {
+		if( ip->saddr == cs->cs_ip.saddr
+		 && ip->daddr == cs->cs_ip.daddr
+		 && th->source == cs->cs_tcp.source
+		 && th->dest == cs->cs_tcp.dest)
+			goto found;
+
+		/* if current equal oldest, at end of list */
+		if ( cs == ocs )
+			break;
+		lcs = cs;
+		cs = cs->next;
+		comp->sls_o_searches++;
+	}
+	/*
+	 * Didn't find it -- re-use oldest cstate.  Send an
+	 * uncompressed packet that tells the other side what
+	 * connection number we're using for this conversation.
+	 *
+	 * Note that since the state list is circular, the oldest
+	 * state points to the newest and we only need to set
+	 * xmit_oldest to update the lru linkage.
+	 */
+	comp->sls_o_misses++;
+	comp->xmit_oldest = lcs->cs_this;
+	goto uncompressed;
+
+found:
+	/*
+	 * Found it -- move to the front on the connection list.
+	 */
+	if(lcs == ocs) {
+		/* found at most recently used */
+	} else if (cs == ocs) {
+		/* found at least recently used */
+		comp->xmit_oldest = lcs->cs_this;
+	} else {
+		/* more than 2 elements */
+		lcs->next = cs->next;
+		cs->next = ocs->next;
+		ocs->next = cs;
+	}
+
+	/*
+	 * Make sure that only what we expect to change changed.
+	 * Check the following:
+	 * IP protocol version, header length & type of service.
+	 * The "Don't fragment" bit.
+	 * The time-to-live field.
+	 * The TCP header length.
+	 * IP options, if any.
+	 * TCP options, if any.
+	 * If any of these things are different between the previous &
+	 * current datagram, we send the current datagram `uncompressed'.
+	 */
+	oth = &cs->cs_tcp;
+
+	if(ip->version != cs->cs_ip.version || ip->ihl != cs->cs_ip.ihl
+	 || ip->tos != cs->cs_ip.tos
+	 || (ip->frag_off & htons(0x4000)) != (cs->cs_ip.frag_off & htons(0x4000))
+	 || ip->ttl != cs->cs_ip.ttl
+	 || th->doff != cs->cs_tcp.doff
+	 || (ip->ihl > 5 && memcmp(ip+1,cs->cs_ipopt,((ip->ihl)-5)*4) != 0)
+	 || (th->doff > 5 && memcmp(th+1,cs->cs_tcpopt,((th->doff)-5)*4) != 0)){
+		goto uncompressed;
+	}
+
+	/*
+	 * Figure out which of the changing fields changed.  The
+	 * receiver expects changes in the order: urgent, window,
+	 * ack, seq (the order minimizes the number of temporaries
+	 * needed in this section of code).
+	 */
+	if(th->urg){
+		deltaS = ntohs(th->urg_ptr);
+		cp = encode(cp,deltaS);
+		changes |= NEW_U;
+	} else if(th->urg_ptr != oth->urg_ptr){
+		/* argh! URG not set but urp changed -- a sensible
+		 * implementation should never do this but RFC793
+		 * doesn't prohibit the change so we have to deal
+		 * with it. */
+		goto uncompressed;
+	}
+	if((deltaS = ntohs(th->window) - ntohs(oth->window)) != 0){
+		cp = encode(cp,deltaS);
+		changes |= NEW_W;
+	}
+	if((deltaA = ntohl(th->ack_seq) - ntohl(oth->ack_seq)) != 0L){
+		if(deltaA > 0x0000ffff)
+			goto uncompressed;
+		cp = encode(cp,deltaA);
+		changes |= NEW_A;
+	}
+	if((deltaS = ntohl(th->seq) - ntohl(oth->seq)) != 0L){
+		if(deltaS > 0x0000ffff)
+			goto uncompressed;
+		cp = encode(cp,deltaS);
+		changes |= NEW_S;
+	}
+
+	switch(changes){
+	case 0:	/* Nothing changed. If this packet contains data and the
+		 * last one didn't, this is probably a data packet following
+		 * an ack (normal on an interactive connection) and we send
+		 * it compressed.  Otherwise it's probably a retransmit,
+		 * retransmitted ack or window probe.  Send it uncompressed
+		 * in case the other side missed the compressed version.
+		 */
+		if(ip->tot_len != cs->cs_ip.tot_len &&
+		   ntohs(cs->cs_ip.tot_len) == hlen)
+			break;
+		goto uncompressed;
+	case SPECIAL_I:
+	case SPECIAL_D:
+		/* actual changes match one of our special case encodings --
+		 * send packet uncompressed.
+		 */
+		goto uncompressed;
+	case NEW_S|NEW_A:
+		if(deltaS == deltaA &&
+		    deltaS == ntohs(cs->cs_ip.tot_len) - hlen){
+			/* special case for echoed terminal traffic */
+			changes = SPECIAL_I;
+			cp = new_seq;
+		}
+		break;
+	case NEW_S:
+		if(deltaS == ntohs(cs->cs_ip.tot_len) - hlen){
+			/* special case for data xfer */
+			changes = SPECIAL_D;
+			cp = new_seq;
+		}
+		break;
+	}
+	deltaS = ntohs(ip->id) - ntohs(cs->cs_ip.id);
+	if(deltaS != 1){
+		cp = encode(cp,deltaS);
+		changes |= NEW_I;
+	}
+	if(th->psh)
+		changes |= TCP_PUSH_BIT;
+	/* Grab the cksum before we overwrite it below.  Then update our
+	 * state with this packet's header.
+	 */
+	csum = th->check;
+	memcpy(&cs->cs_ip,ip,20);
+	memcpy(&cs->cs_tcp,th,20);
+	/* We want to use the original packet as our compressed packet.
+	 * (cp - new_seq) is the number of bytes we need for compressed
+	 * sequence numbers.  In addition we need one byte for the change
+	 * mask, one for the connection id and two for the tcp checksum.
+	 * So, (cp - new_seq) + 4 bytes of header are needed.
+	 */
+	deltaS = cp - new_seq;
+	if(compress_cid == 0 || comp->xmit_current != cs->cs_this){
+		cp = ocp;
+		*cpp = ocp;
+		*cp++ = changes | NEW_C;
+		*cp++ = cs->cs_this;
+		comp->xmit_current = cs->cs_this;
+	} else {
+		cp = ocp;
+		*cpp = ocp;
+		*cp++ = changes;
+	}
+	*(__sum16 *)cp = csum;
+	cp += 2;
+/* deltaS is now the size of the change section of the compressed header */
+	memcpy(cp,new_seq,deltaS);	/* Write list of deltas */
+	memcpy(cp+deltaS,icp+hlen,isize-hlen);
+	comp->sls_o_compressed++;
+	ocp[0] |= SL_TYPE_COMPRESSED_TCP;
+	return isize - hlen + deltaS + (cp - ocp);
+
+	/* Update connection state cs & send uncompressed packet (i.e.,
+	 * a regular ip/tcp packet but with the 'conversation id' we hope
+	 * to use on future compressed packets in the protocol field).
+	 */
+uncompressed:
+	memcpy(&cs->cs_ip,ip,20);
+	memcpy(&cs->cs_tcp,th,20);
+	if (ip->ihl > 5)
+	  memcpy(cs->cs_ipopt, ip+1, ((ip->ihl) - 5) * 4);
+	if (th->doff > 5)
+	  memcpy(cs->cs_tcpopt, th+1, ((th->doff) - 5) * 4);
+	comp->xmit_current = cs->cs_this;
+	comp->sls_o_uncompressed++;
+	memcpy(ocp, icp, isize);
+	*cpp = ocp;
+	ocp[9] = cs->cs_this;
+	ocp[0] |= SL_TYPE_UNCOMPRESSED_TCP;
+	return isize;
+}
+
+
+int
+slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize)
+{
+	int changes;
+	long x;
+	struct tcphdr *thp;
+	struct iphdr *ip;
+	struct cstate *cs;
+	int len, hdrlen;
+	unsigned char *cp = icp;
+
+	/* We've got a compressed packet; read the change byte */
+	comp->sls_i_compressed++;
+	if(isize < 3){
+		comp->sls_i_error++;
+		return 0;
+	}
+	changes = *cp++;
+	if(changes & NEW_C){
+		/* Make sure the state index is in range, then grab the state.
+		 * If we have a good state index, clear the 'discard' flag.
+		 */
+		x = *cp++;	/* Read conn index */
+		if(x < 0 || x > comp->rslot_limit)
+			goto bad;
+
+		/* Check if the cstate is initialized */
+		if (!comp->rstate[x].initialized)
+			goto bad;
+
+		comp->flags &=~ SLF_TOSS;
+		comp->recv_current = x;
+	} else {
+		/* this packet has an implicit state index.  If we've
+		 * had a line error since the last time we got an
+		 * explicit state index, we have to toss the packet. */
+		if(comp->flags & SLF_TOSS){
+			comp->sls_i_tossed++;
+			return 0;
+		}
+	}
+	cs = &comp->rstate[comp->recv_current];
+	thp = &cs->cs_tcp;
+	ip = &cs->cs_ip;
+
+	thp->check = *(__sum16 *)cp;
+	cp += 2;
+
+	thp->psh = (changes & TCP_PUSH_BIT) ? 1 : 0;
+/*
+ * we can use the same number for the length of the saved header and
+ * the current one, because the packet wouldn't have been sent
+ * as compressed unless the options were the same as the previous one
+ */
+
+	hdrlen = ip->ihl * 4 + thp->doff * 4;
+
+	switch(changes & SPECIALS_MASK){
+	case SPECIAL_I:		/* Echoed terminal traffic */
+		{
+		short i;
+		i = ntohs(ip->tot_len) - hdrlen;
+		thp->ack_seq = htonl( ntohl(thp->ack_seq) + i);
+		thp->seq = htonl( ntohl(thp->seq) + i);
+		}
+		break;
+
+	case SPECIAL_D:			/* Unidirectional data */
+		thp->seq = htonl( ntohl(thp->seq) +
+				  ntohs(ip->tot_len) - hdrlen);
+		break;
+
+	default:
+		if(changes & NEW_U){
+			thp->urg = 1;
+			if((x = decode(&cp)) == -1) {
+				goto bad;
+			}
+			thp->urg_ptr = htons(x);
+		} else
+			thp->urg = 0;
+		if(changes & NEW_W){
+			if((x = decode(&cp)) == -1) {
+				goto bad;
+			}
+			thp->window = htons( ntohs(thp->window) + x);
+		}
+		if(changes & NEW_A){
+			if((x = decode(&cp)) == -1) {
+				goto bad;
+			}
+			thp->ack_seq = htonl( ntohl(thp->ack_seq) + x);
+		}
+		if(changes & NEW_S){
+			if((x = decode(&cp)) == -1) {
+				goto bad;
+			}
+			thp->seq = htonl( ntohl(thp->seq) + x);
+		}
+		break;
+	}
+	if(changes & NEW_I){
+		if((x = decode(&cp)) == -1) {
+			goto bad;
+		}
+		ip->id = htons (ntohs (ip->id) + x);
+	} else
+		ip->id = htons (ntohs (ip->id) + 1);
+
+	/*
+	 * At this point, cp points to the first byte of data in the
+	 * packet.  Put the reconstructed TCP and IP headers back on the
+	 * packet.  Recalculate IP checksum (but not TCP checksum).
+	 */
+
+	len = isize - (cp - icp);
+	if (len < 0)
+		goto bad;
+	len += hdrlen;
+	ip->tot_len = htons(len);
+	ip->check = 0;
+
+	memmove(icp + hdrlen, cp, len - hdrlen);
+
+	cp = icp;
+	memcpy(cp, ip, 20);
+	cp += 20;
+
+	if (ip->ihl > 5) {
+	  memcpy(cp, cs->cs_ipopt, (ip->ihl - 5) * 4);
+	  cp += (ip->ihl - 5) * 4;
+	}
+
+	put_unaligned(ip_fast_csum(icp, ip->ihl),
+		      &((struct iphdr *)icp)->check);
+
+	memcpy(cp, thp, 20);
+	cp += 20;
+
+	if (thp->doff > 5) {
+	  memcpy(cp, cs->cs_tcpopt, ((thp->doff) - 5) * 4);
+	  cp += ((thp->doff) - 5) * 4;
+	}
+
+	return len;
+bad:
+	comp->sls_i_error++;
+	return slhc_toss( comp );
+}
+
+
+int
+slhc_remember(struct slcompress *comp, unsigned char *icp, int isize)
+{
+	struct cstate *cs;
+	unsigned ihl;
+
+	unsigned char index;
+
+	if(isize < 20) {
+		/* The packet is shorter than a legal IP header */
+		comp->sls_i_runt++;
+		return slhc_toss( comp );
+	}
+	/* Peek at the IP header's IHL field to find its length */
+	ihl = icp[0] & 0xf;
+	if(ihl < 20 / 4){
+		/* The IP header length field is too small */
+		comp->sls_i_runt++;
+		return slhc_toss( comp );
+	}
+	index = icp[9];
+	icp[9] = IPPROTO_TCP;
+
+	if (ip_fast_csum(icp, ihl)) {
+		/* Bad IP header checksum; discard */
+		comp->sls_i_badcheck++;
+		return slhc_toss( comp );
+	}
+	if(index > comp->rslot_limit) {
+		comp->sls_i_error++;
+		return slhc_toss(comp);
+	}
+
+	/* Update local state */
+	cs = &comp->rstate[comp->recv_current = index];
+	comp->flags &=~ SLF_TOSS;
+	memcpy(&cs->cs_ip,icp,20);
+	memcpy(&cs->cs_tcp,icp + ihl*4,20);
+	if (ihl > 5)
+	  memcpy(cs->cs_ipopt, icp + sizeof(struct iphdr), (ihl - 5) * 4);
+	if (cs->cs_tcp.doff > 5)
+	  memcpy(cs->cs_tcpopt, icp + ihl*4 + sizeof(struct tcphdr), (cs->cs_tcp.doff - 5) * 4);
+	cs->cs_hsize = ihl*2 + cs->cs_tcp.doff*2;
+	cs->initialized = true;
+	/* Put headers back on packet
+	 * Neither header checksum is recalculated
+	 */
+	comp->sls_i_uncompressed++;
+	return isize;
+}
+
+int
+slhc_toss(struct slcompress *comp)
+{
+	if ( comp == NULLSLCOMPR )
+		return 0;
+
+	comp->flags |= SLF_TOSS;
+	return 0;
+}
+
+#else /* CONFIG_INET */
+
+int
+slhc_toss(struct slcompress *comp)
+{
+  printk(KERN_DEBUG "Called IP function on non IP-system: slhc_toss");
+  return -EINVAL;
+}
+int
+slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize)
+{
+  printk(KERN_DEBUG "Called IP function on non IP-system: slhc_uncompress");
+  return -EINVAL;
+}
+int
+slhc_compress(struct slcompress *comp, unsigned char *icp, int isize,
+	unsigned char *ocp, unsigned char **cpp, int compress_cid)
+{
+  printk(KERN_DEBUG "Called IP function on non IP-system: slhc_compress");
+  return -EINVAL;
+}
+
+int
+slhc_remember(struct slcompress *comp, unsigned char *icp, int isize)
+{
+  printk(KERN_DEBUG "Called IP function on non IP-system: slhc_remember");
+  return -EINVAL;
+}
+
+void
+slhc_free(struct slcompress *comp)
+{
+  printk(KERN_DEBUG "Called IP function on non IP-system: slhc_free");
+}
+struct slcompress *
+slhc_init(int rslots, int tslots)
+{
+  printk(KERN_DEBUG "Called IP function on non IP-system: slhc_init");
+  return NULL;
+}
+
+#endif /* CONFIG_INET */
+
+/* VJ header compression */
+EXPORT_SYMBOL(slhc_init);
+EXPORT_SYMBOL(slhc_free);
+EXPORT_SYMBOL(slhc_remember);
+EXPORT_SYMBOL(slhc_compress);
+EXPORT_SYMBOL(slhc_uncompress);
+EXPORT_SYMBOL(slhc_toss);
+
+MODULE_LICENSE("Dual BSD/GPL");