- removed all Group fields translations (oure rpm now can handle translating

[packages/kernel.git] / br2684-against2.4.10.diff

diff -urN linux.orig/Documentation/Configure.help linux/Documentation/Configure.help
--- linux.orig/Documentation/Configure.help	Sat Apr 21 18:05:00 2001
+++ linux/Documentation/Configure.help	Sat Apr 21 18:06:09 2001
@@ -5328,6 +5328,19 @@
   briefly removed during revalidation. If you say Y here, packets to
   such neighbours are silently discarded instead.
 
+RFC1483/2684 Bridged protocols
+CONFIG_ATM_BR2684
+  ATM PVCs can carry ethernet PDUs according to rfc2684 (formerly 1483)
+  This device will act like an ethernet from the kernels point of view,
+  with the traffic being carried by ATM PVCs (currently 1 PVC/device).
+  This is sometimes used over DSL lines.  If in doubt, say N.
+
+Per-VC IP filter kludge
+CONFIG_ATM_BR2684_IPFILTER
+  This is an experimental mechanism for users who need to terminating a
+  large number of IP-only vcc's.  Do not enable this unless you are sure
+  you know what you are doing.
+
 LAN Emulation (LANE) support
 CONFIG_ATM_LANE
   LAN Emulation emulates services of existing LANs across an ATM
@@ -7558,6 +7571,13 @@
   This driver requires a specially patched pppd daemon.  The patch to
   pppd, along with binaries of a patched pppd package can be found at:
   http://www.shoshin.uwaterloo.ca/~mostrows
+
+PPP over ATM (EXPERIMENTAL)
+CONFIG_PPPOATM
+  PPP over ATM is one of several protocols used over DSL lines.
+  If you are connecting to a DSL line using an internal ATM or
+  DSL adaptor (as opposed to an ethernet card) then there is
+  a good possibility you will need this protocol.
  
 Wireless LAN (non-hamradio)
 CONFIG_NET_RADIO
diff -urN linux.orig/MAINTAINERS linux/MAINTAINERS
--- linux.orig/MAINTAINERS	Sat Apr 21 18:05:00 2001
+++ linux/MAINTAINERS	Sat Apr 21 18:07:12 2001
@@ -1060,6 +1060,11 @@
 L:	linux-ppp@vger.kernel.org
 S:	Maintained
 
+PPP OVER ATM (RFC 2364)
+P:      Mitchell Blank Jr
+M:      mitch@sfgoth.com
+S:      Maintained
+
 PPP OVER ETHERNET
 P:	Michal Ostrowski
 M:	mostrows@styx.uwaterloo.ca
diff -urN linux.orig/arch/sparc/config.in linux/arch/sparc/config.in
--- linux.orig/arch/sparc/config.in	Sat Apr 21 18:04:59 2001
+++ linux/arch/sparc/config.in	Sat Apr 21 18:06:09 2001
@@ -215,6 +215,12 @@
         dep_tristate '  PPP support for sync tty ports' CONFIG_PPP_SYNC_TTY $CONFIG_PPP
         dep_tristate '  PPP Deflate compression' CONFIG_PPP_DEFLATE $CONFIG_PPP
         dep_tristate '  PPP BSD-Compress compression' CONFIG_PPP_BSDCOMP m
+	if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then
+	  dep_tristate '  PPP over Ethernet (EXPERIMENTAL)' CONFIG_PPPOE $CONFIG_PPP
+	  if [ "$CONFIG_ATM" = "y" ]; then
+	    dep_tristate '  PPP over ATM (EXPERIMENTAL)' CONFIG_PPPOATM $CONFIG_PPP
+	  fi
+	fi
       fi
       tristate '  SLIP (serial line) support' CONFIG_SLIP
       if [ "$CONFIG_SLIP" != "n" ]; then
diff -urN linux.orig/drivers/net/Config.in linux/drivers/net/Config.in
--- linux.orig/drivers/net/Config.in	Sat Apr 21 18:04:55 2001
+++ linux/drivers/net/Config.in	Sat Apr 21 18:06:09 2001
@@ -245,6 +245,9 @@
    dep_tristate '  PPP BSD-Compress compression' CONFIG_PPP_BSDCOMP $CONFIG_PPP
    if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then
       dep_tristate '  PPP over Ethernet (EXPERIMENTAL)' CONFIG_PPPOE $CONFIG_PPP
+      if [ "$CONFIG_ATM" = "y" ]; then
+         dep_tristate '  PPP over ATM (EXPERIMENTAL)' CONFIG_PPPOATM $CONFIG_PPP $CONFIG_EXPERIMENTAL
+      fi
    fi
 fi

diff -urN linux.orig/include/linux/atm.h linux/include/linux/atm.h
--- linux.orig/include/linux/atm.h	Tue Mar 27 01:49:24 2001
+++ linux/include/linux/atm.h	Sat Apr 21 18:06:09 2001
@@ -235,6 +235,7 @@
     void *arg;
 };
 
+typedef unsigned short atm_backend_t;
 
 #ifdef __KERNEL__
 
diff -urN linux.orig/include/linux/atmbr2684.h linux/include/linux/atmbr2684.h
--- linux.orig/include/linux/atmbr2684.h	Thu Jan  1 01:00:00 1970
+++ linux/include/linux/atmbr2684.h	Sat Apr 21 18:06:09 2001
@@ -0,0 +1,101 @@
+#ifndef _LINUX_ATMBR2684_H
+#define _LINUX_ATMBR2684_H
+
+#include <linux/atm.h>
+#include <linux/if.h>		/* For IFNAMSIZ */
+
+/*
+ * Type of media we're bridging (ethernet, token ring, etc)  Currently only
+ * ethernet is supported
+ */
+#define BR2684_MEDIA_ETHERNET	(0)	/* 802.3 */
+#define BR2684_MEDIA_802_4	(1)	/* 802.4 */
+#define BR2684_MEDIA_TR		(2)	/* 802.5 - token ring */
+#define BR2684_MEDIA_FDDI	(3)
+#define BR2684_MEDIA_802_6	(4)	/* 802.6 */
+
+/*
+ * Is there FCS inbound on this VC?  This currently isn't supported.
+ */
+#define BR2684_FCSIN_NO		(0)
+#define BR2684_FCSIN_IGNORE	(1)
+#define BR2684_FCSIN_VERIFY	(2)
+
+/*
+ * Is there FCS outbound on this VC?  This currently isn't supported.
+ */
+#define BR2684_FCSOUT_NO	(0)
+#define BR2684_FCSOUT_SENDZERO	(1)
+#define BR2684_FCSOUT_GENERATE	(2)
+
+/*
+ * Does this VC include LLC encapsulation?
+ */
+#define BR2684_ENCAPS_VC	(0)	/* VC-mux */
+#define BR2684_ENCAPS_LLC	(1)
+#define BR2684_ENCAPS_AUTODETECT (2)	/* Unsuported */
+
+/*
+ * This is for the ATM_NEWBACKENDIF call - these are like socket families:
+ * the first element of the structure is the backend number and the rest
+ * is per-backend specific
+ */
+struct atm_newif_br2684 {
+	atm_backend_t	backend_num;	/* ATM_BACKEND_BR2684 */
+	int		media;		/* BR2684_MEDIA_* */
+	char		ifname[IFNAMSIZ];
+	int		mtu;
+};
+
+/*
+ * This structure is used to specify a br2684 interface - either by a
+ * positive integer (returned by ATM_NEWBACKENDIF) or the interfaces name
+ */
+#define BR2684_FIND_BYNOTHING	(0)
+#define BR2684_FIND_BYNUM	(1)
+#define BR2684_FIND_BYIFNAME	(2)
+struct br2684_if_spec {
+	int method;			/* BR2684_FIND_* */
+	union {
+		char		ifname[IFNAMSIZ];
+		int		devnum;
+	} spec;
+};
+
+/*
+ * This is for the ATM_SETBACKEND call - these are like socket families:
+ * the first element of the structure is the backend number and the rest
+ * is per-backend specific
+ */
+struct atm_backend_br2684 {
+	atm_backend_t	backend_num;	/* ATM_BACKEND_BR2684 */
+	struct br2684_if_spec ifspec;
+	int	fcs_in;		/* BR2684_FCSIN_* */
+	int	fcs_out;	/* BR2684_FCSOUT_* */
+	int	fcs_auto;	/* 1: fcs_{in,out} disabled if no FCS rx'ed */
+	int	encaps;		/* BR2684_ENCAPS_* */
+	int	has_vpiid;	/* 1: use vpn_id - Unsupported */
+	__u8	vpn_id[7];
+	int	send_padding;	/* unsupported */
+	int	min_size;	/* we will pad smaller packets than this */
+};
+
+/*
+ * The BR2684_SETFILT ioctl is an experimental mechanism for folks
+ * terminating a large number of IP-only vcc's.  When netfilter allows
+ * efficient per-if in/out filters, this support will be removed
+ */
+struct br2684_filter {
+	__u32	prefix;		/* network byte order */
+	__u32	netmask;	/* 0 = disable filter */
+};
+
+struct br2684_filter_set {
+	struct br2684_if_spec ifspec;
+	struct br2684_filter filter;
+};
+
+#define BR2684_SETFILT	_IOW( 'a', ATMIOC_BACKEND + 0, \
+				struct br2684_filter_set)
+
+#endif /* _LINUX_ATMBR2684_H */
diff -urN linux.orig/include/linux/atmdev.h linux/include/linux/atmdev.h
--- linux.orig/include/linux/atmdev.h	Tue Mar 27 01:50:03 2001
+++ linux/include/linux/atmdev.h	Sat Apr 21 18:06:09 2001
@@ -87,6 +87,20 @@
 #define ATM_SETSC	_IOW('a',ATMIOC_SPECIAL+1,int)
 					/* enable or disable single-copy */
 
+#define ATM_SETBACKEND _IOW('a',ATMIOC_SPECIAL+2,atm_backend_t)
+                                       /* set backend handler */
+#define ATM_NEWBACKENDIF _IOW('a',ATMIOC_SPECIAL+3,atm_backend_t)
+                                       /* use backend to make new if */
+
+/*
+ * These are backend handkers that can be set via the ATM_SETBACKEND call
+ * above.  In the future we may support dynamic loading of these - for now,
+ * they're just being used to share the ATMIOC_BACKEND ioctls
+ */
+#define ATM_BACKEND_RAW                0
+#define ATM_BACKEND_PPP                1       /* PPPoATM - RFC2364 */
+#define ATM_BACKEND_BR2684     2       /* Bridged RFC1483/2684 */
+
 /* for ATM_GETTYPE */
 #define ATM_ITFTYP_LEN	8	/* maximum length of interface type name */
 
diff -urN linux.orig/include/linux/atmioc.h linux/include/linux/atmioc.h
--- linux.orig/include/linux/atmioc.h	Wed Feb  9 03:23:13 2000
+++ linux/include/linux/atmioc.h	Sat Apr 21 18:06:09 2001
@@ -27,7 +27,9 @@
 #define ATMIOC_SARPRV_END 0x7f
 #define ATMIOC_ITF	  0x80 /* Interface ioctls, globally unique */
 #define ATMIOC_ITF_END	  0x8f
-/* 0x90-0xbf: Reserved for future use */
+#define ATMIOC_BACKEND   0x90 /* ATM generic backend ioctls, u. per backend */
+#define ATMIOC_BACKEND_END 0xaf
+/* 0xb0-0xbf: Reserved for future use */
 #define ATMIOC_AREQUIPA	  0xc0 /* Application requested IP over ATM, glob. u. */
 #define ATMIOC_LANE	  0xd0 /* LAN Emulation, globally unique */
 #define ATMIOC_MPOA       0xd8 /* MPOA, globally unique */
diff -urN linux.orig/include/linux/atmppp.h linux/include/linux/atmppp.h
--- linux.orig/include/linux/atmppp.h	Thu Jan  1 01:00:00 1970
+++ linux/include/linux/atmppp.h	Sat Apr 21 18:06:09 2001
@@ -0,0 +1,24 @@
+/* atmppp.h - RFC2364 PPPoATM */
+
+/* Written 2000 by Mitchell Blank Jr */
+
+#ifndef _LINUX_ATMPPP_H
+#define _LINUX_ATMPPP_H
+
+#include <linux/atm.h>
+
+#define PPPOATM_ENCAPS_AUTODETECT	(0)
+#define PPPOATM_ENCAPS_VC		(1)
+#define PPPOATM_ENCAPS_LLC		(2)
+
+/*
+ * This is for the ATM_SETBACKEND call - these are like socket families:
+ * the first element of the structure is the backend number and the rest
+ * is per-backend specific
+ */
+struct atm_backend_ppp {
+	atm_backend_t	backend_num;	/* ATM_BACKEND_PPP */
+	int		encaps;		/* PPPOATM_ENCAPS_* */
+};
+
+#endif	/* _LINUX_ATMPPP_H */
diff -urN linux.orig/net/Config.in linux/net/Config.in
--- linux.orig/net/Config.in	Sat Apr 21 18:05:00 2001
+++ linux/net/Config.in	Sat Apr 21 18:06:09 2001
@@ -45,6 +45,10 @@
       if [ "$CONFIG_INET" = "y" -a "$CONFIG_ATM_LANE" != "n" ]; then
 	 tristate '    Multi-Protocol Over ATM (MPOA) support' CONFIG_ATM_MPOA
       fi
+      tristate '  RFC1483/2684 Bridged protocols' CONFIG_ATM_BR2684
+      if [ "$CONFIG_ATM_BR2684" != "n" ]; then
+            bool '    Per-VC IP filter kludge' CONFIG_ATM_BR2684_IPFILTER
+      fi
    fi
 fi
 
diff -urN linux.orig/net/atm/Makefile linux/net/atm/Makefile
--- linux.orig/net/atm/Makefile	Tue Mar 27 01:36:30 2001
+++ linux/net/atm/Makefile	Sat Apr 21 18:06:09 2001
@@ -21,6 +21,15 @@
 NEED_IPCOM = ipcommon.o
 endif
 
+ifeq ($(CONFIG_ATM_BR2684),y)
+  NEED_IPCOM = ipcommon.o
+else
+  ifeq ($(CONFIG_ATM_BR2684),m)
+	NEED_IPCOM = ipcommon.o
+  endif
+endif
+obj-$(CONFIG_ATM_BR2684) += br2684.o
+
 ifeq ($(CONFIG_NET_SCH_ATM),y)
 NEED_IPCOM = ipcommon.o
 endif
@@ -33,6 +42,7 @@
 
 obj-$(CONFIG_ATM_LANE) += lec.o
 obj-$(CONFIG_ATM_MPOA) += mpoa.o
+obj-$(CONFIG_PPPOATM)  += pppoatm.o
 
 include $(TOPDIR)/Rules.make
 
diff -urN linux.orig/net/atm/br2684.c linux/net/atm/br2684.c
--- linux.orig/net/atm/br2684.c	Thu Jan  1 01:00:00 1970
+++ linux/net/atm/br2684.c	Sat Apr 21 18:06:09 2001
@@ -0,0 +1,794 @@
+/*
+Experimental ethernet netdevice using ATM AAL5 as underlying carrier
+(RFC1483 obsoleted by RFC2684) for Linux 2.4
+Author: Marcell GAL, 2000, XDSL Ltd, Hungary
+*/
+
+#include <linux/module.h>
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <asm/uaccess.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/etherdevice.h>
+#include <net/arp.h>
+#include <linux/rtnetlink.h>
+#include <linux/atmbr2684.h>
+
+#include "ipcommon.h"
+
+/*
+ * Define this to use a version of the code which interacts with the higher
+ * layers in a more intellegent way, by always reserving enough space for
+ * our header at the begining of the packet.  However, there may still be
+ * some problems with programs like tcpdump.  In 2.5 we'll sort out what
+ * we need to do to get this perfect.  For now we just will copy the packet
+ * if we need space for the header
+ */
+/* #define FASTER_VERSION */
+
+#ifdef DEBUG
+#define DPRINTK(format, args...) printk(KERN_DEBUG "br2684: " format, ##args)
+#else
+#define DPRINTK(format, args...)
+#endif
+
+#ifdef SKB_DEBUG
+static void skb_debug(const struct sk_buff *skb)
+{
+#define NUM2PRINT 50
+	char buf[NUM2PRINT * 3 + 1];	/* 3 chars per byte */
+	int i = 0;
+	for (i = 0; i < skb->len && i < NUM2PRINT; i++) {
+		sprintf(buf + i * 3, "%2.2x ", 0xff & skb->data[i]);
+	}
+	printk(KERN_DEBUG "br2684: skb: %s\n", buf);
+}
+#else
+#define skb_debug(skb)	do {} while (0)
+#endif
+
+static unsigned char llc_oui_pid_pad[] =
+    { 0xAA, 0xAA, 0x03, 0x00, 0x80, 0xC2, 0x00, 0x07, 0x00, 0x00 };
+#define PADLEN	(2)
+
+enum br2684_encaps {
+	e_vc  = BR2684_ENCAPS_VC,
+	e_llc = BR2684_ENCAPS_LLC,
+};
+
+struct br2684_vcc {
+	struct atm_vcc  *atmvcc;
+	struct br2684_dev *brdev;
+	/* keep old push,pop functions for chaining */
+	void (*old_push)(struct atm_vcc *vcc,struct sk_buff *skb);
+	/* void (*old_pop)(struct atm_vcc *vcc,struct sk_buff *skb); */
+	enum br2684_encaps encaps;
+	struct list_head brvccs;
+#ifdef CONFIG_ATM_BR2684_IPFILTER
+	struct br2684_filter filter;
+#endif /* CONFIG_ATM_BR2684_IPFILTER */
+#ifndef FASTER_VERSION
+	unsigned copies_needed, copies_failed;
+#endif /* FASTER_VERSION */
+};
+
+struct br2684_dev {
+	struct net_device net_dev;
+	struct list_head br2684_devs;
+	int number;
+	struct list_head brvccs; /* one device <=> one vcc (before xmas) */
+	struct net_device_stats stats;
+	int mac_was_set;
+};
+
+/*
+ * This lock should be held for writing any time the list of devices or
+ * their attached vcc's could be altered.  It should be held for reading
+ * any time these are being queried.  Note that we sometimes need to
+ * do read-locking under interrupt context, so write locking must block
+ * the current CPU's interrupts
+ */
+static rwlock_t devs_lock = RW_LOCK_UNLOCKED;
+
+static LIST_HEAD(br2684_devs);
+
+static inline struct br2684_dev *BRPRIV(const struct net_device *net_dev)
+{
+	return (struct br2684_dev *) ((char *) (net_dev) -
+	    (unsigned long) (&((struct br2684_dev *) 0)->net_dev));
+}
+
+static inline struct br2684_dev *list_entry_brdev(const struct list_head *le)
+{
+	return list_entry(le, struct br2684_dev, br2684_devs);
+}
+
+static inline struct br2684_vcc *BR2684_VCC(const struct atm_vcc *atmvcc)
+{
+	return (struct br2684_vcc *) (atmvcc->user_back);
+}
+
+static inline struct br2684_vcc *list_entry_brvcc(const struct list_head *le)
+{
+	return list_entry(le, struct br2684_vcc, brvccs);
+}
+
+/* Caller should hold read_lock(&devs_lock) */
+static struct br2684_dev *br2684_find_dev(const struct br2684_if_spec *s)
+{
+	struct list_head *lh;
+	struct br2684_dev *brdev;
+	switch (s->method) {
+	case BR2684_FIND_BYNUM:
+		list_for_each(lh, &br2684_devs) {
+			brdev = list_entry_brdev(lh);
+			if (brdev->number == s->spec.devnum)
+				return brdev;
+		}
+		break;
+	case BR2684_FIND_BYIFNAME:
+		list_for_each(lh, &br2684_devs) {
+			brdev = list_entry_brdev(lh);
+			if (!strncmp(brdev->net_dev.name, s->spec.ifname,
+			    sizeof brdev->net_dev.name))
+				return brdev;
+		}
+		break;
+	}
+	return NULL;
+}
+
+/*
+ * Send a packet out a particular vcc.  Not to useful right now, but paves
+ * the way for multiple vcc's per itf.  Returns true if we can send,
+ * otherwise false
+ */
+static int br2684_xmit_vcc(struct sk_buff *skb, struct br2684_dev *brdev,
+	struct br2684_vcc *brvcc)
+{
+	struct atm_vcc *atmvcc;
+#ifdef FASTER_VERSION
+	if (brvcc->encaps == e_llc)
+		memcpy(skb_push(skb, 8), llc_oui_pid_pad, 8);
+	/* last 2 bytes of llc_oui_pid_pad are managed by header routines;
+	   yes, you got it: 8 + 2 = sizeof(llc_oui_pid_pad)
+	 */
+#else
+	int minheadroom = (brvcc->encaps == e_llc) ? 10 : 2;
+	if (skb_headroom(skb) < minheadroom) {
+		struct sk_buff *skb2 = skb_realloc_headroom(skb, minheadroom);
+		brvcc->copies_needed++;
+		dev_kfree_skb(skb);
+		if (skb2 == NULL) {
+			brvcc->copies_failed++;
+			return 0;
+		}
+		skb = skb2;
+	}
+	skb_push(skb, minheadroom);
+	if (brvcc->encaps == e_llc)
+		memcpy(skb->data, llc_oui_pid_pad, 10);
+	else
+		memset(skb->data, 0, 2);
+#endif /* FASTER_VERSION */
+	skb_debug(skb);
+
+	ATM_SKB(skb)->vcc = atmvcc = brvcc->atmvcc;
+	DPRINTK("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, atmvcc, atmvcc->dev);
+	if (!atm_may_send(atmvcc, skb->truesize)) {
+		/* we free this here for now, because we cannot know in a higher 
+			layer whether the skb point it supplied wasn't freed yet.
+			now, it always is.
+		*/
+		dev_kfree_skb(skb);
+		return 0;
+		}
+	atomic_add(skb->truesize, &atmvcc->tx_inuse);
+	ATM_SKB(skb)->iovcnt = 0;
+	ATM_SKB(skb)->atm_options = atmvcc->atm_options;
+	brdev->stats.tx_packets++;
+	brdev->stats.tx_bytes += skb->len;
+	atmvcc->send(atmvcc, skb);
+	return 1;
+}
+
+static inline struct br2684_vcc *pick_outgoing_vcc(struct sk_buff *skb,
+	struct br2684_dev *brdev)
+{
+	return list_empty(&brdev->brvccs) ? NULL :
+	    list_entry_brvcc(brdev->brvccs.next); /* 1 vcc/dev right now */
+}
+
+static int br2684_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct br2684_dev *brdev = BRPRIV(dev);
+	struct br2684_vcc *brvcc;
+
+	DPRINTK("br2684_start_xmit, skb->dst=%p\n", skb->dst);
+	read_lock(&devs_lock);
+	brvcc = pick_outgoing_vcc(skb, brdev);
+	if (brvcc == NULL) {
+		DPRINTK("no vcc attached to dev %s\n", dev->name);
+		brdev->stats.tx_errors++;
+		brdev->stats.tx_carrier_errors++;
+		/* netif_stop_queue(dev); */
+		dev_kfree_skb(skb);
+		read_unlock(&devs_lock);
+		return -EUNATCH;
+	}
+	if (!br2684_xmit_vcc(skb, brdev, brvcc)) {
+		/*
+		 * We should probably use netif_*_queue() here, but that
+		 * involves added complication.  We need to walk before
+		 * we can run
+		 */
+		/* don't free here! this pointer might be no longer valid!
+		dev_kfree_skb(skb);
+		*/
+		brdev->stats.tx_errors++;
+		brdev->stats.tx_fifo_errors++;
+	}
+	read_unlock(&devs_lock);
+	return 0;
+}
+
+static struct net_device_stats *br2684_get_stats(struct net_device *dev)
+{
+	DPRINTK("br2684_get_stats\n");
+	return &BRPRIV(dev)->stats;
+}
+
+#ifdef FASTER_VERSION
+/*
+ * These mirror eth_header and eth_header_cache.  They are not usually
+ * exported for use in modules, so we grab them from net_device
+ * after ether_setup() is done with it.  Bit of a hack.
+ */
+static int (*my_eth_header)(struct sk_buff *, struct net_device *,
+	unsigned short, void *, void *, unsigned);
+static int (*my_eth_header_cache)(struct neighbour *, struct hh_cache *);
+
+static int
+br2684_header(struct sk_buff *skb, struct net_device *dev,
+	      unsigned short type, void *daddr, void *saddr, unsigned len)
+{
+	u16 *pad_before_eth;
+	int t = my_eth_header(skb, dev, type, daddr, saddr, len);
+	if (t > 0) {
+		pad_before_eth = (u16 *) skb_push(skb, 2);
+		*pad_before_eth = 0;
+		return dev->hard_header_len;	/* or return 16; ? */
+	} else
+		return t;
+}
+
+static int
+br2684_header_cache(struct neighbour *neigh, struct hh_cache *hh)
+{
+/* hh_data is 16 bytes long. if encaps is ether-llc we need 24, so
+xmit will add the additional header part in that case */
+	u16 *pad_before_eth = (u16 *)(hh->hh_data);
+	int t = my_eth_header_cache(neigh, hh);
+	DPRINTK("br2684_header_cache, neigh=%p, hh_cache=%p\n", neigh, hh);
+	if (t < 0)
+		return t;
+	else {
+		*pad_before_eth = 0;
+		hh->hh_len = PADLEN + ETH_HLEN;
+	}
+	return 0;
+}
+
+/*
+ * This is similar to eth_type_trans, which cannot be used because of
+ * our dev->hard_header_len
+ */
+static inline unsigned short br_type_trans(struct sk_buff *skb,
+					       struct net_device *dev)
+{
+	struct ethhdr *eth;
+	unsigned char *rawp;
+	eth = skb->mac.ethernet;
+
+	if (*eth->h_dest & 1) {
+		if (memcmp(eth->h_dest, dev->broadcast, ETH_ALEN) == 0)
+			skb->pkt_type = PACKET_BROADCAST;
+		else
+			skb->pkt_type = PACKET_MULTICAST;
+	}
+
+	else if (memcmp(eth->h_dest, dev->dev_addr, ETH_ALEN))
+		skb->pkt_type = PACKET_OTHERHOST;
+
+	if (ntohs(eth->h_proto) >= 1536)
+		return eth->h_proto;
+
+	rawp = skb->data;
+
+	/*
+	 * This is a magic hack to spot IPX packets. Older Novell breaks
+	 * the protocol design and runs IPX over 802.3 without an 802.2 LLC
+	 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
+	 * won't work for fault tolerant netware but does for the rest.
+	 */
+	if (*(unsigned short *) rawp == 0xFFFF)
+		return htons(ETH_P_802_3);
+
+	/*
+	 * Real 802.2 LLC
+	 */
+	return htons(ETH_P_802_2);
+}
+#endif /* FASTER_VERSION */
+
+/*
+ * We remember when the MAC gets set, so we don't override it later with
+ * the ESI of the ATM card of the first VC
+ */
+static int (*my_eth_mac_addr)(struct net_device *, void *);
+static int br2684_mac_addr(struct net_device *dev, void *p)
+{
+	int err = my_eth_mac_addr(dev, p);
+	if (!err)
+		BRPRIV(dev)->mac_was_set = 1;
+	return err;
+}
+
+#ifdef CONFIG_ATM_BR2684_IPFILTER
+/* this IOCTL is experimental. */
+static int br2684_setfilt(struct atm_vcc *atmvcc, unsigned long arg)
+{
+	struct br2684_vcc *brvcc;
+	struct br2684_filter_set fs;
+
+	if (copy_from_user(&fs, (void *) arg, sizeof fs))
+		return -EFAULT;
+	if (fs.ifspec.method != BR2684_FIND_BYNOTHING) {
+		/*
+		 * This is really a per-vcc thing, but we can also search
+		 * by device
+		 */
+		struct br2684_dev *brdev;
+		read_lock(&devs_lock);
+		brdev = br2684_find_dev(&fs.ifspec);
+		if (brdev == NULL || list_empty(&brdev->brvccs) ||
+		    brdev->brvccs.next != brdev->brvccs.prev)  /* >1 VCC */
+			brvcc = NULL;
+		else
+			brvcc = list_entry_brvcc(brdev->brvccs.next);
+		read_unlock(&devs_lock);
+		if (brvcc == NULL)
+			return -ESRCH;
+	} else
+		brvcc = BR2684_VCC(atmvcc);
+	memcpy(&brvcc->filter, &fs.filter, sizeof(brvcc->filter));
+	return 0;
+}
+
+/* Returns 1 if packet should be dropped */
+static inline int
+packet_fails_filter(u16 type, struct br2684_vcc *brvcc, struct sk_buff *skb)
+{
+	if (brvcc->filter.netmask == 0)
+		return 0;			/* no filter in place */
+	if (type == __constant_htons(ETH_P_IP) &&
+	    (((struct iphdr *) (skb->data))->daddr & brvcc->filter.
+	     netmask) == brvcc->filter.prefix)
+		return 0;
+	if (type == __constant_htons(ETH_P_ARP))
+		return 0;
+	/* TODO: we should probably filter ARPs too.. don't want to have
+	 *   them returning values that don't make sense, or is that ok?
+	 */
+	return 1;		/* drop */
+}
+#endif /* CONFIG_ATM_BR2684_IPFILTER */
+
+static void br2684_close_vcc(struct br2684_vcc *brvcc)
+{
+	DPRINTK("removing VCC %p from dev %p\n", brvcc, brvcc->brdev);
+	write_lock_irq(&devs_lock);
+	list_del(&brvcc->brvccs);
+	write_unlock_irq(&devs_lock);
+	brvcc->atmvcc->user_back = NULL;	/* what about vcc->recvq ??? */
+	brvcc->old_push(brvcc->atmvcc, NULL);	/* pass on the bad news */
+	kfree(brvcc);
+	MOD_DEC_USE_COUNT;
+}
+
+/* when AAL5 PDU comes in: */
+static void br2684_push(struct atm_vcc *atmvcc, struct sk_buff *skb)
+{
+	struct br2684_vcc *brvcc = BR2684_VCC(atmvcc);
+	struct br2684_dev *brdev = brvcc->brdev;
+	int plen = sizeof(llc_oui_pid_pad) + ETH_HLEN;
+
+	DPRINTK("br2684_push\n");
+
+	if (skb == NULL) {	/* skb==NULL means VCC is being destroyed */
+		br2684_close_vcc(brvcc);
+		return;
+	}
+
+	skb_debug(skb);
+	atm_return(atmvcc, skb->truesize);
+	DPRINTK("skb from brdev %p\n", brdev);
+	if (brvcc->encaps == e_llc) {
+		/* let us waste some time for checking the encapsulation.
+		   Note, that only 7 char is checked so frames with a valid FCS
+		   are also accepted (but FCS is not checked of course) */
+		if (memcmp(skb->data, llc_oui_pid_pad, 7)) {
+			brdev->stats.rx_errors++;
+			dev_kfree_skb(skb);
+			return;
+		}
+	} else {
+		plen = PADLEN + ETH_HLEN;	/* pad, dstmac,srcmac, ethtype */
+		/* first 2 chars should be 0 */
+		if (*((u16 *) (skb->data)) != 0) {
+			brdev->stats.rx_errors++;
+			dev_kfree_skb(skb);
+			return;
+		}
+	}
+	if (skb->len < plen) {
+		brdev->stats.rx_errors++;
+		dev_kfree_skb(skb);	/* dev_ not needed? */
+		return;
+	}
+
+#ifdef FASTER_VERSION
+	/* FIXME: tcpdump shows that pointer to mac header is 2 bytes earlier,
+	   than should be. What else should I set? */
+	skb_pull(skb, plen);
+	skb->mac.raw = ((char *) (skb->data)) - ETH_HLEN;
+	skb->pkt_type = PACKET_HOST;
+#ifdef CONFIG_BR2684_FAST_TRANS
+	skb->protocol = ((u16 *) skb->data)[-1];
+#else				/* some protocols might require this: */
+	skb->protocol = br_type_trans(skb, &brdev->net_dev);
+#endif /* CONFIG_BR2684_FAST_TRANS */
+#else
+	skb_pull(skb, plen - ETH_HLEN);
+	skb->protocol = eth_type_trans(skb, &brdev->net_dev);
+#endif /* FASTER_VERSION */
+#ifdef CONFIG_ATM_BR2684_IPFILTER
+	if (packet_fails_filter(skb->protocol, brvcc, skb)) {
+		brdev->stats.rx_dropped++;
+		dev_kfree_skb(skb);
+		return;
+	}
+#endif /* CONFIG_ATM_BR2684_IPFILTER */
+	skb->dev = &brdev->net_dev;
+	ATM_SKB(skb)->vcc = atmvcc;	/* needed ? */
+	DPRINTK("received packet's protocol: %x\n", ntohs(skb->protocol));
+	skb_debug(skb);
+	if (!(brdev->net_dev.flags & IFF_UP)) { /* sigh, interface is down */
+		brdev->stats.rx_dropped++;
+		dev_kfree_skb(skb);
+		return;
+	}
+	brdev->stats.rx_packets++;
+	brdev->stats.rx_bytes += skb->len;
+	netif_rx(skb);
+}
+
+static int br2684_regvcc(struct atm_vcc *atmvcc, unsigned long arg)
+{
+/* assign a vcc to a dev
+Note: we do not have explicit unassign, but look at _push()
+*/
+	int err;
+	struct br2684_vcc *brvcc;
+	struct sk_buff_head copy;
+	struct sk_buff *skb;
+	struct br2684_dev *brdev;
+	struct atm_backend_br2684 be;
+
+	MOD_INC_USE_COUNT;
+	if (copy_from_user(&be, (void *) arg, sizeof be)) {
+		MOD_DEC_USE_COUNT;
+		return -EFAULT;
+	}
+	write_lock_irq(&devs_lock);
+	brdev = br2684_find_dev(&be.ifspec);
+	if (brdev == NULL) {
+		printk(KERN_ERR
+		    "br2684: tried to attach to non-existant device\n");
+		err = -ENXIO;
+		goto error;
+	}
+	if (atmvcc->push == NULL) {
+		err = -EBADFD;
+		goto error;
+	}
+	if (!list_empty(&brdev->brvccs)) {	/* Only 1 VCC/dev right now */
+		err = -EEXIST;
+		goto error;
+	}
+	if (be.fcs_in != BR2684_FCSIN_NO || be.fcs_out != BR2684_FCSOUT_NO ||
+	    be.fcs_auto || be.has_vpiid || be.send_padding || (be.encaps !=
+	    BR2684_ENCAPS_VC && be.encaps != BR2684_ENCAPS_LLC) ||
+	    be.min_size != 0) {
+		err = -EINVAL;
+		goto error;
+	}
+	brvcc = kmalloc(sizeof(struct br2684_vcc), GFP_KERNEL);
+	if (!brvcc) {
+		err = -ENOMEM;
+		goto error;
+	}
+	memset(brvcc, 0, sizeof(struct br2684_vcc));
+	DPRINTK("br2684_regvcc vcc=%p, encaps=%d, brvcc=%p\n", atmvcc, be.encaps,
+		brvcc);
+	if (list_empty(&brdev->brvccs) && !brdev->mac_was_set) {
+		unsigned char *esi = atmvcc->dev->esi;
+		if (esi[0] | esi[1] | esi[2] | esi[3] | esi[4] | esi[5])
+			memcpy(brdev->net_dev.dev_addr, esi,
+			    brdev->net_dev.addr_len);
+		else
+			brdev->net_dev.dev_addr[2] = 1;
+	}
+	list_add(&brvcc->brvccs, &brdev->brvccs);
+	write_unlock_irq(&devs_lock);
+	brvcc->brdev = brdev;
+	brvcc->atmvcc = atmvcc;
+	atmvcc->user_back = brvcc;
+	brvcc->encaps = (enum br2684_encaps) be.encaps;
+	brvcc->old_push = atmvcc->push;
+	barrier();
+	atmvcc->push = br2684_push;
+	skb_queue_head_init(&copy);
+	skb_migrate(&atmvcc->recvq, &copy);
+	while ((skb = skb_dequeue(&copy))) {
+		BRPRIV(skb->dev)->stats.rx_bytes -= skb->len;
+		BRPRIV(skb->dev)->stats.rx_packets--;
+		br2684_push(atmvcc, skb);
+	}
+	return 0;
+    error:
+	write_unlock_irq(&devs_lock);
+	MOD_DEC_USE_COUNT;
+	return err;
+}
+
+static int br2684_create(unsigned long arg)
+{
+	int err;
+	struct br2684_dev *brdev;
+	struct atm_newif_br2684 ni;
+
+	DPRINTK("br2684_create\n");
+	/*
+	 * We track module use by vcc's NOT the devices they're on.  We're
+	 * protected here against module death by the kernel_lock, but if
+	 * we need to sleep we should make sure that the module doesn't
+	 * disappear under us.
+	 */
+	MOD_INC_USE_COUNT;
+	if (copy_from_user(&ni, (void *) arg, sizeof ni)) {
+		MOD_DEC_USE_COUNT;
+		return -EFAULT;
+	}
+	if (ni.media != BR2684_MEDIA_ETHERNET || ni.mtu != 1500) {
+		MOD_DEC_USE_COUNT;
+		return -EINVAL;
+	}
+	if ((brdev = kmalloc(sizeof(struct br2684_dev), GFP_KERNEL)) == NULL) {
+		MOD_DEC_USE_COUNT;
+		return -ENOMEM;
+	}
+	memset(brdev, 0, sizeof(struct br2684_dev));
+	INIT_LIST_HEAD(&brdev->brvccs);
+
+	write_lock_irq(&devs_lock);
+	brdev->number = list_empty(&br2684_devs) ? 1 :
+	    list_entry_brdev(br2684_devs.prev)->number + 1;
+	list_add_tail(&brdev->br2684_devs, &br2684_devs);
+	write_unlock_irq(&devs_lock);
+
+	if (ni.ifname[0] != '\0') {
+		memcpy(brdev->net_dev.name, ni.ifname,
+		    sizeof(brdev->net_dev.name));
+		brdev->net_dev.name[sizeof(brdev->net_dev.name) - 1] = '\0';
+	} else
+		sprintf(brdev->net_dev.name, "nas%d", brdev->number);
+	DPRINTK("registered netdev %s\n", brdev->net_dev.name);
+	ether_setup(&brdev->net_dev);
+	brdev->mac_was_set = 0;
+#ifdef FASTER_VERSION
+	my_eth_header = brdev->net_dev.hard_header;
+	brdev->net_dev.hard_header = br2684_header;
+	my_eth_header_cache = brdev->net_dev.hard_header_cache;
+	brdev->net_dev.hard_header_cache = br2684_header_cache;
+	brdev->net_dev.hard_header_len = sizeof(llc_oui_pid_pad) + ETH_HLEN;	/* 10 + 14 */
+#endif
+	my_eth_mac_addr = brdev->net_dev.set_mac_address;
+	brdev->net_dev.set_mac_address = br2684_mac_addr;
+	brdev->net_dev.hard_start_xmit = br2684_start_xmit;
+	brdev->net_dev.get_stats = br2684_get_stats;
+
+	/* open, stop, do_ioctl ? */
+	err = register_netdev(&brdev->net_dev);
+	MOD_DEC_USE_COUNT;
+	if (err < 0) {
+		printk(KERN_ERR "br2684_create: register_netdev failed\n");
+		write_lock_irq(&devs_lock);
+		list_del(&brdev->br2684_devs);
+		write_unlock_irq(&devs_lock);
+		kfree(brdev);
+		return err;
+	}
+	return 0;
+}
+
+/*
+ * This handles ioctls actually performed on our vcc - we must return
+ * -ENOIOCTLCMD for any unrecognized ioctl
+ */
+static int br2684_ioctl(struct atm_vcc *atmvcc, unsigned int cmd,
+	unsigned long arg)
+{
+	int err;
+	switch(cmd) {
+	case ATM_SETBACKEND:
+	case ATM_NEWBACKENDIF: {
+		atm_backend_t b;
+		MOD_INC_USE_COUNT;
+		err = get_user(b, (atm_backend_t *) arg);
+		MOD_DEC_USE_COUNT;
+		if (err)
+			return -EFAULT;
+		if (b != ATM_BACKEND_BR2684)
+			return -ENOIOCTLCMD;
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+		if (cmd == ATM_SETBACKEND)
+			return br2684_regvcc(atmvcc, arg);
+		else
+			return br2684_create(arg);
+		}
+#ifdef CONFIG_ATM_BR2684_IPFILTER
+	case BR2684_SETFILT:
+		if (atmvcc->push != br2684_push)
+			return -ENOIOCTLCMD;
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+		MOD_INC_USE_COUNT;
+		err = br2684_setfilt(atmvcc, arg);
+		MOD_DEC_USE_COUNT;
+		return err;
+#endif /* CONFIG_ATM_BR2684_IPFILTER */
+	}
+	return -ENOIOCTLCMD;
+}
+
+/* Never put more than 256 bytes in at once */
+static int br2684_proc_engine(loff_t pos, char *buf)
+{
+	struct list_head *lhd, *lhc;
+	struct br2684_dev *brdev;
+	struct br2684_vcc *brvcc;
+	list_for_each(lhd, &br2684_devs) {
+		brdev = list_entry_brdev(lhd);
+		if (pos-- == 0)
+			return sprintf(buf, "dev %.16s: num=%d, mac=%02X:%02X:"
+			    "%02X:%02X:%02X:%02X (%s)\n", brdev->net_dev.name,
+			    brdev->number,
+			    brdev->net_dev.dev_addr[0],
+			    brdev->net_dev.dev_addr[1],
+			    brdev->net_dev.dev_addr[2],
+			    brdev->net_dev.dev_addr[3],
+			    brdev->net_dev.dev_addr[4],
+			    brdev->net_dev.dev_addr[5],
+			    brdev->mac_was_set ? "set" : "auto");
+		list_for_each(lhc, &brdev->brvccs) {
+			brvcc = list_entry_brvcc(lhc);
+			if (pos-- == 0)
+				return sprintf(buf, "  vcc %d.%d.%d: encaps=%s"
+#ifndef FASTER_VERSION
+				    ", failed copies %u/%u"
+#endif /* FASTER_VERSION */
+				    "\n", brvcc->atmvcc->dev->number,
+				    brvcc->atmvcc->vpi, brvcc->atmvcc->vci,
+				    (brvcc->encaps == e_llc) ? "LLC" : "VC"
+#ifndef FASTER_VERSION
+				    , brvcc->copies_failed
+				    , brvcc->copies_needed
+#endif /* FASTER_VERSION */
+				    );
+#ifdef CONFIG_ATM_BR2684_IPFILTER
+#define b1(var, byte)	((u8 *) &brvcc->filter.var)[byte]
+#define bs(var)		b1(var, 0), b1(var, 1), b1(var, 2), b1(var, 3)
+			if (brvcc->filter.netmask != 0 && pos-- == 0)
+				return sprintf(buf, "    filter=%d.%d.%d.%d/"
+				    "%d.%d.%d.%d\n", bs(prefix), bs(netmask));
+#undef bs
+#undef b1
+#endif /* CONFIG_ATM_BR2684_IPFILTER */
+		}
+	}
+	return 0;
+}
+
+static ssize_t br2684_proc_read(struct file *file, char *buf, size_t count,
+	loff_t *pos)
+{
+	unsigned long page;
+	int len = 0, x, left;
+	page = get_free_page(GFP_KERNEL);
+	if (!page)
+		return -ENOMEM;
+	left = PAGE_SIZE - 256;
+	if (count < left)
+		left = count;
+	read_lock(&devs_lock);
+	for (;;) {
+		x = br2684_proc_engine(*pos, &((char *) page)[len]);
+		if (x == 0)
+			break;
+		if (x > left)
+			/*
+			 * This should only happen if the user passed in
+			 * a "count" too small for even one line
+			 */
+			x = -EINVAL;
+		if (x < 0) {
+			len = x;
+			break;
+		}
+		len += x;
+		left -= x;
+		(*pos)++;
+		if (left < 256)
+			break;
+	}
+	read_unlock(&devs_lock);
+	if (len > 0 && copy_to_user(buf, (char *) page, len))
+		len = -EFAULT;
+	free_page(page);
+	return len;
+}
+
+static struct file_operations br2684_proc_operations = {
+	read: br2684_proc_read,
+};
+
+extern struct proc_dir_entry *atm_proc_root;	/* from proc.c */
+
+extern int (*br2684_ioctl_hook)(struct atm_vcc *, unsigned int, unsigned long);
+
+/* the following avoids some spurious warnings from the compiler */
+#define UNUSED __attribute__((unused))
+
+static int __init UNUSED br2684_init(void)
+{
+	struct proc_dir_entry *p;
+	if ((p = create_proc_entry("br2684", 0, atm_proc_root)) == NULL)
+		return -ENOMEM;
+	p->proc_fops = &br2684_proc_operations;
+	br2684_ioctl_hook = br2684_ioctl;
+	return 0;
+}
+
+static void __exit UNUSED br2684_exit(void)
+{
+	struct br2684_dev *brdev;
+	br2684_ioctl_hook = NULL;
+	remove_proc_entry("br2684", atm_proc_root);
+	while (!list_empty(&br2684_devs)) {
+		brdev = list_entry_brdev(br2684_devs.next);
+		unregister_netdev(&brdev->net_dev);
+		list_del(&brdev->br2684_devs);
+		kfree(brdev);
+	}
+}
+
+module_init(br2684_init);
+module_exit(br2684_exit);
+
+MODULE_AUTHOR("Marcell GAL");
+MODULE_DESCRIPTION("RFC2684 bridged protocols over ATM/AAL5");
diff -urN linux.orig/net/atm/common.c linux/net/atm/common.c
--- linux.orig/net/atm/common.c	Sat Apr 21 18:04:58 2001
+++ linux/net/atm/common.c	Sat Apr 21 18:06:09 2001
@@ -58,6 +58,18 @@
 #endif
 #endif
 
+#if defined(CONFIG_PPPOATM) || defined(CONFIG_PPPOATM_MODULE)
+int (*pppoatm_ioctl_hook)(struct atm_vcc *, unsigned int, unsigned long);
+EXPORT_SYMBOL(pppoatm_ioctl_hook);
+#endif
+
+#if defined(CONFIG_ATM_BR2684) || defined(CONFIG_ATM_BR2684_MODULE)
+int (*br2684_ioctl_hook)(struct atm_vcc *, unsigned int, unsigned long);
+#endif
+#ifdef CONFIG_ATM_BR2684_MODULE
+EXPORT_SYMBOL(br2684_ioctl_hook);
+#endif
+
 #include "resources.h"		/* atm_find_dev */
 #include "common.h"		/* prototypes */
 #include "protocols.h"		/* atm_init_<transport> */
@@ -774,6 +786,20 @@
 		default:
 			break;
 	}
+#if defined(CONFIG_PPPOATM) || defined(CONFIG_PPPOATM_MODULE)
+	if (pppoatm_ioctl_hook &&
+	    (error = pppoatm_ioctl_hook(vcc, cmd, arg)) != -ENOIOCTLCMD) {
+		spin_unlock (&atm_dev_lock); 
+		return error;
+	}
+#endif
+#if defined(CONFIG_ATM_BR2684) || defined(CONFIG_ATM_BR2684_MODULE)
+	if (br2684_ioctl_hook &&
+	    (error = br2684_ioctl_hook(vcc, cmd, arg)) != -ENOIOCTLCMD) {
+		spin_unlock (&atm_dev_lock); 
+		return error;
+	}
+#endif
 	if (get_user(buf,&((struct atmif_sioc *) arg)->arg)) {
 		ret_val = -EFAULT;
 		goto done;
diff -urN linux.orig/net/atm/pppoatm.c linux/net/atm/pppoatm.c
--- linux.orig/net/atm/pppoatm.c	Thu Jan  1 01:00:00 1970
+++ linux/net/atm/pppoatm.c	Sat Apr 21 18:06:09 2001
@@ -0,0 +1,373 @@
+/* net/atm/pppoatm.c - RFC2364 PPP over ATM/AAL5 */
+
+/* Copyright 1999-2000 by Mitchell Blank Jr */
+/* Based on clip.c; 1995-1999 by Werner Almesberger, EPFL LRC/ICA */
+/* And on ppp_async.c; Copyright 1999 Paul Mackerras */
+/* And help from Jens Axboe */
+
+/*
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ *
+ * This driver provides the encapsulation and framing for sending
+ * and receiving PPP frames in ATM AAL5 PDUs.
+ */
+
+/*
+ * One shortcoming of this driver is that it does not comply with
+ * section 8 of RFC2364 - we are supposed to detect a change
+ * in encapsulation and immediately abort the connection (in order
+ * to avoid a black-hole being created if our peer loses state
+ * and changes encapsulation unilaterally.  However, since the
+ * ppp_generic layer actually does the decapsulation, we need
+ * a way of notifying it when we _think_ there might be a problem)
+ * There's two cases:
+ *   1.	LLC-encapsulation was missing when it was enabled.  In
+ *	this case, we should tell the upper layer "tear down
+ *	this session if this skb looks ok to you"
+ *   2.	LLC-encapsulation was present when it was disabled.  Then
+ *	we need to tell the upper layer "this packet may be
+ *	ok, but if its in error tear down the session"
+ * These hooks are not yet available in ppp_generic
+ */
+
+#include <linux/module.h>
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/skbuff.h>
+#include <linux/atm.h>
+#include <linux/atmdev.h>
+#include <linux/ppp_defs.h>
+#include <linux/if_ppp.h>
+#include <linux/ppp_channel.h>
+#include <linux/atmppp.h>
+
+#if 0
+#define DPRINTK(format, args...) \
+	printk(KERN_DEBUG "pppoatm: " format, ##args)
+#else
+#define DPRINTK(format, args...)
+#endif
+
+enum pppoatm_encaps {
+	e_autodetect = PPPOATM_ENCAPS_AUTODETECT,
+	e_vc = PPPOATM_ENCAPS_VC,
+	e_llc = PPPOATM_ENCAPS_LLC,
+};
+
+struct pppoatm_vcc {
+	struct atm_vcc	*atmvcc;	/* VCC descriptor */
+	void (*old_push)(struct atm_vcc *, struct sk_buff *);
+	void (*old_pop)(struct atm_vcc *, struct sk_buff *);
+					/* keep old push/pop for detaching */
+	enum pppoatm_encaps encaps;
+	int flags;			/* SC_COMP_PROT - compress protocol */
+	struct ppp_channel chan;	/* interface to generic ppp layer */
+	struct tasklet_struct wakeup_tasklet;
+};
+
+/*
+ * Header used for LLC Encapsulated PPP (4 bytes) followed by the LCP protocol
+ * ID (0xC021) used in autodetection
+ */
+static const unsigned char pppllc[6] = { 0xFE, 0xFE, 0x03, 0xCF, 0xC0, 0x21 };
+#define LLC_LEN		(4)
+
+static inline struct pppoatm_vcc *atmvcc_to_pvcc(const struct atm_vcc *atmvcc)
+{
+	return (struct pppoatm_vcc *) (atmvcc->user_back);
+}
+
+static inline struct pppoatm_vcc *chan_to_pvcc(const struct ppp_channel *chan)
+{
+	return (struct pppoatm_vcc *) (chan->private);
+}
+
+/*
+ * We can't do this directly from our _pop handler, since the ppp code
+ * doesn't want to be called in interrupt context, so we do it from
+ * a tasklet
+ */
+static void pppoatm_wakeup_sender(unsigned long arg)
+{
+	ppp_output_wakeup((struct ppp_channel *) arg);
+}
+
+/*
+ * This gets called every time the ATM card has finished sending our
+ * skb.  The ->old_pop will take care up normal atm flow control,
+ * but we also need to wake up the device if we blocked it
+ */
+static void pppoatm_pop(struct atm_vcc *atmvcc, struct sk_buff *skb)
+{
+	struct pppoatm_vcc *pvcc = atmvcc_to_pvcc(atmvcc);
+	pvcc->old_pop(atmvcc, skb);
+	/*
+	 * We don't really always want to do this since it's
+	 * really inefficient - it would be much better if we could
+	 * test if we had actually throttled the generic layer.
+	 * Unfortunately then there would be a nasty SMP race where
+	 * we could clear that flag just as we refuse another packet.
+	 * For now we do the safe thing.
+	 */
+	tasklet_schedule(&pvcc->wakeup_tasklet);
+}
+
+/*
+ * Unbind from PPP - currently we only do this when closing the socket,
+ * but we could put this into an ioctl if need be
+ */
+static void pppoatm_unassign_vcc(struct atm_vcc *atmvcc)
+{
+	struct pppoatm_vcc *pvcc;
+	pvcc = atmvcc_to_pvcc(atmvcc);
+	atmvcc->push = pvcc->old_push;
+	atmvcc->pop = pvcc->old_pop;
+	tasklet_disable(&pvcc->wakeup_tasklet);
+	ppp_unregister_channel(&pvcc->chan);
+	atmvcc->user_back = NULL;
+	kfree(pvcc);
+	/* Gee, I hope we have the big kernel lock here... */
+	MOD_DEC_USE_COUNT;
+}
+
+/* Called when an AAL5 PDU comes in */
+static void pppoatm_push(struct atm_vcc *atmvcc, struct sk_buff *skb)
+{
+	struct pppoatm_vcc *pvcc = atmvcc_to_pvcc(atmvcc);
+	DPRINTK("pppoatm push\n");
+	if (skb == NULL) {			/* VCC was closed */
+		DPRINTK("removing ATMPPP VCC %p\n", pvcc);
+		pppoatm_unassign_vcc(atmvcc);
+		atmvcc->push(atmvcc, NULL);	/* Pass along bad news */
+		return;
+	}
+	atm_return(atmvcc, skb->truesize);
+	switch (pvcc->encaps) {
+	case e_llc:
+		if (skb->len < LLC_LEN ||
+		    memcmp(skb->data, pppllc, LLC_LEN))
+			goto error;
+		skb_pull(skb, LLC_LEN);
+		break;
+	case e_autodetect:
+		if (pvcc->chan.ppp == NULL) {	/* Not bound yet! */
+			kfree_skb(skb);
+			return;
+		}
+		if (skb->len >= sizeof(pppllc) &&
+		    !memcmp(skb->data, pppllc, sizeof(pppllc))) {
+			pvcc->encaps = e_llc;
+			skb_pull(skb, LLC_LEN);
+			break;
+		}
+		if (skb->len >= (sizeof(pppllc) - LLC_LEN) &&
+		    !memcmp(skb->data, &pppllc[LLC_LEN],
+		    sizeof(pppllc) - LLC_LEN)) {
+			pvcc->encaps = e_vc;
+			pvcc->chan.mtu += LLC_LEN;
+			break;
+		}
+		DPRINTK("(unit %d): Couldn't autodetect yet "
+		    "(skb: %02X %02X %02X %02X %02X %02X)\n",
+		    pvcc->chan.unit,
+		    skb->data[0], skb->data[1], skb->data[2],
+		    skb->data[3], skb->data[4], skb->data[5]);
+		goto error;
+	case e_vc:
+		break;
+	}
+	ppp_input(&pvcc->chan, skb);
+	return;
+    error:
+	kfree_skb(skb);
+	ppp_input_error(&pvcc->chan, 0);
+}
+
+/*
+ * Called by the ppp_generic.c to send a packet - returns true if packet
+ * was accepted.  If we return false, then it's our job to call
+ * ppp_output_wakeup(chan) when we're feeling more up to it.
+ * Note that in the ENOMEM case (as opposed to the !atm_may_send case)
+ * we should really drop the packet, but the generic layer doesn't
+ * support this yet.  We just return 'DROP_PACKET' which we actually define
+ * as success, just to be clear what we're really doing.
+ */
+#define DROP_PACKET 1
+static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb)
+{
+	struct pppoatm_vcc *pvcc = chan_to_pvcc(chan);
+	ATM_SKB(skb)->vcc = pvcc->atmvcc;
+	DPRINTK("(unit %d): pppoatm_send (skb=0x%p, vcc=0x%p)\n",
+	    pvcc->chan.unit, skb, pvcc->atmvcc);
+	if (skb->data[0] == '\0' && (pvcc->flags & SC_COMP_PROT))
+		(void) skb_pull(skb, 1);
+	switch (pvcc->encaps) {		/* LLC encapsulation needed */
+	case e_llc:
+		if (skb_headroom(skb) < LLC_LEN) {
+			struct sk_buff *n;
+			n = skb_realloc_headroom(skb, LLC_LEN);
+			if (n != NULL &&
+			    !atm_may_send(pvcc->atmvcc, n->truesize)) {
+				kfree_skb(n);
+				goto nospace;
+			}
+			kfree_skb(skb);
+			if ((skb = n) == NULL)
+				return DROP_PACKET;
+		} else if (!atm_may_send(pvcc->atmvcc, skb->truesize))
+			goto nospace;
+		memcpy(skb_push(skb, LLC_LEN), pppllc, LLC_LEN);
+		break;
+	case e_vc:
+		if (!atm_may_send(pvcc->atmvcc, skb->truesize))
+			goto nospace;
+		break;
+	case e_autodetect:
+		DPRINTK("(unit %d): Trying to send without setting encaps!\n",
+		    pvcc->chan.unit);
+		kfree_skb(skb);
+		return 1;
+	}
+	atomic_add(skb->truesize, &ATM_SKB(skb)->vcc->tx_inuse);
+	ATM_SKB(skb)->iovcnt = 0;
+	ATM_SKB(skb)->atm_options = ATM_SKB(skb)->vcc->atm_options;
+	DPRINTK("(unit %d): atm_skb(%p)->vcc(%p)->dev(%p)\n",
+	    pvcc->chan.unit, skb, ATM_SKB(skb)->vcc,
+	    ATM_SKB(skb)->vcc->dev);
+	return ATM_SKB(skb)->vcc->send(ATM_SKB(skb)->vcc, skb)
+	    ? DROP_PACKET : 1;
+    nospace:
+	/*
+	 * We don't have space to send this SKB now, but we might have
+	 * already applied SC_COMP_PROT compression, so may need to undo
+	 */
+	if ((pvcc->flags & SC_COMP_PROT) && skb_headroom(skb) > 0 &&
+	    skb->data[-1] == '\0')
+		(void) skb_push(skb, 1);
+	return 0;
+}
+
+/* This handles ioctls sent to the /dev/ppp interface */
+static int pppoatm_devppp_ioctl(struct ppp_channel *chan, unsigned int cmd,
+	unsigned long arg)
+{
+	switch (cmd) {
+	case PPPIOCGFLAGS:
+		return put_user(chan_to_pvcc(chan)->flags, (int *) arg)
+		    ? -EFAULT : 0;
+	case PPPIOCSFLAGS:
+		return get_user(chan_to_pvcc(chan)->flags, (int *) arg)
+		    ? -EFAULT : 0;
+	}
+	return -ENOTTY;
+}
+
+static /*const*/ struct ppp_channel_ops pppoatm_ops = {
+	start_xmit: pppoatm_send,
+	ioctl: pppoatm_devppp_ioctl,
+};
+
+static int pppoatm_assign_vcc(struct atm_vcc *atmvcc, unsigned long arg)
+{
+	struct atm_backend_ppp be;
+	struct pppoatm_vcc *pvcc;
+	int err;
+	/*
+	 * Each PPPoATM instance has its own tasklet - this is just a
+	 * prototypical one used to initialize them
+	 */
+	static const DECLARE_TASKLET(tasklet_proto, pppoatm_wakeup_sender, 0);
+	if (copy_from_user(&be, (void *) arg, sizeof be))
+		return -EFAULT;
+	if (be.encaps != PPPOATM_ENCAPS_AUTODETECT &&
+	    be.encaps != PPPOATM_ENCAPS_VC && be.encaps != PPPOATM_ENCAPS_LLC)
+		return -EINVAL;
+	MOD_INC_USE_COUNT;
+	pvcc = kmalloc(sizeof(*pvcc), GFP_KERNEL);
+	if (pvcc == NULL) {
+		MOD_DEC_USE_COUNT;
+		return -ENOMEM;
+	}
+	memset(pvcc, 0, sizeof(*pvcc));
+	pvcc->atmvcc = atmvcc;
+	pvcc->old_push = atmvcc->push;
+	pvcc->old_pop = atmvcc->pop;
+	pvcc->encaps = (enum pppoatm_encaps) be.encaps;
+	pvcc->chan.private = pvcc;
+	pvcc->chan.ops = &pppoatm_ops;
+	pvcc->chan.mtu = atmvcc->qos.txtp.max_sdu - PPP_HDRLEN -
+	    (be.encaps == e_vc ? 0 : LLC_LEN);
+	pvcc->wakeup_tasklet = tasklet_proto;
+	pvcc->wakeup_tasklet.data = (unsigned long) &pvcc->chan;
+	if ((err = ppp_register_channel(&pvcc->chan)) != 0) {
+		kfree(pvcc);
+		return err;
+	}
+	atmvcc->user_back = pvcc;
+	atmvcc->push = pppoatm_push;
+	atmvcc->pop = pppoatm_pop;
+	return 0;
+}
+
+/*
+ * This handles ioctls actually performed on our vcc - we must return
+ * -ENOIOCTLCMD for any unrecognized ioctl
+ */
+static int pppoatm_ioctl(struct atm_vcc *atmvcc, unsigned int cmd,
+	unsigned long arg)
+{
+	int err;
+	if (cmd != ATM_SETBACKEND && atmvcc->push != pppoatm_push)
+		return -ENOIOCTLCMD;
+	switch (cmd) {
+	case ATM_SETBACKEND: {
+		atm_backend_t b;
+		MOD_INC_USE_COUNT;
+		err = get_user(b, (atm_backend_t *) arg);
+		MOD_DEC_USE_COUNT;
+		if (err)
+			return -EFAULT;
+		if (b != ATM_BACKEND_PPP)
+			return -ENOIOCTLCMD;
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+		return pppoatm_assign_vcc(atmvcc, arg);
+		}
+	case PPPIOCGCHAN:
+	case PPPIOCGUNIT:
+		MOD_INC_USE_COUNT;
+		err = put_user((cmd == PPPIOCGCHAN) ?
+		    ppp_channel_index(&atmvcc_to_pvcc(atmvcc)->chan) :
+		    ppp_unit_number(&atmvcc_to_pvcc(atmvcc)->chan),
+		    (int *) arg);
+		MOD_DEC_USE_COUNT;
+		return err ? -EFAULT : 0;
+	}
+	return -ENOIOCTLCMD;
+}
+
+/* the following avoids some spurious warnings from the compiler */
+#define UNUSED __attribute__((unused))
+
+extern int (*pppoatm_ioctl_hook)(struct atm_vcc *,
+	 unsigned int, unsigned long);
+
+static int __init UNUSED pppoatm_init(void)
+{
+	pppoatm_ioctl_hook = pppoatm_ioctl;
+	return 0;
+}
+
+static void __exit UNUSED pppoatm_exit(void)
+{
+	pppoatm_ioctl_hook = NULL;
+}
+
+module_init(pppoatm_init);
+module_exit(pppoatm_exit);
+
+MODULE_AUTHOR("Mitchell Blank Jr <mitch@sfgoth.com>");
+MODULE_DESCRIPTION("RFC2364 PPP over ATM/AAL5");