Merge http://uml.bkbits.net/net-2.5

into home.transmeta.com:/home/torvalds/v2.5/linux

12 files changed, 743 insertions, 152 deletions

diff --git a/arch/um/Kconfig_net b/arch/um/Kconfig_net
index ba311513abc3..443a74bd622d 100644
--- a/arch/um/Kconfig_net
+++ b/arch/um/Kconfig_net
@@ -5,30 +5,177 @@ menu "Network Devices"
 # UML virtual driver
 config UML_NET
 	bool "Virtual network device"
+	help
+        While the User-Mode port cannot directly talk to any physical
+        hardware devices, this choice and the following transport options
+        provide one or more virtual network devices through which the UML
+        kernels can talk to each other, the host, and with the host's help,
+        machines on the outside world.
+
+        For more information, including explanations of the networking and
+        sample configurations, see
+        <http://user-mode-linux.sourceforge.net/networking.html>.
+
+        If you'd like to be able to enable networking in the User-Mode
+        linux environment, say Y; otherwise say N.  Note that you must
+        enable at least one of the following transport options to actually
+        make use of UML networking.
 
 config UML_NET_ETHERTAP
 	bool "Ethertap transport"
 	depends on UML_NET
+	help
+        The Ethertap User-Mode Linux network transport allows a single
+        running UML to exchange packets with its host over one of the
+        host's Ethertap devices, such as /dev/tap0.  Additional running
+        UMLs can use additional Ethertap devices, one per running UML.
+        While the UML believes it's on a (multi-device, broadcast) virtual
+        Ethernet network, it's in fact communicating over a point-to-point
+        link with the host.
+
+        To use this, your host kernel must have support for Ethertap
+        devices.  Also, if your host kernel is 2.4.x, it must have 
+        CONFIG_NETLINK_DEV configured as Y or M.
+
+        For more information, see
+        <http://user-mode-linux.sourceforge.net/networking.html>  That site
+        has examples of the UML command line to use to enable Ethertap
+        networking.
+
+        If you'd like to set up an IP network with the host and/or the
+        outside world, say Y to this, the Daemon Transport and/or the 
+        Slip Transport.  You'll need at least one of them, but may choose
+        more than one without conflict.  If you don't need UML networking,
+        say N.
 
 config UML_NET_TUNTAP
 	bool "TUN/TAP transport"
 	depends on UML_NET
+	help
+        The UML TUN/TAP network transport allows a UML instance to exchange
+        packets with the host over a TUN/TAP device.  This option will only
+        work with a 2.4 host, unless you've applied the TUN/TAP patch to
+        your 2.2 host kernel.
+
+        To use this transport, your host kernel must have support for TUN/TAP
+        devices, either built-in or as a module.
 
 config UML_NET_SLIP
 	bool "SLIP transport"
 	depends on UML_NET
+	help
+        The slip User-Mode Linux network transport allows a running UML to
+        network with its host over a point-to-point link.  Unlike Ethertap,
+        which can carry any Ethernet frame (and hence even non-IP packets),
+        the slip transport can only carry IP packets.
+
+        To use this, your host must support slip devices.
+
+        For more information, see
+        <http://user-mode-linux.sourceforge.net/networking.html>.  That site
+        has examples of the UML command line to use to enable slip
+        networking, and details of a few quirks with it.
+
+        The Ethertap Transport is preferred over slip because of its
+        limitations.  If you prefer slip, however, say Y here.  Otherwise
+        choose the Multicast transport (to network multiple UMLs on 
+        multiple hosts), Ethertap (to network with the host and the
+        outside world), and/or the Daemon transport (to network multiple
+        UMLs on a single host).  You may choose more than one without
+        conflict.  If you don't need UML networking, say N.
 
 config UML_NET_DAEMON
 	bool "Daemon transport"
 	depends on UML_NET
+	help
+        This User-Mode Linux network transport allows one or more running
+        UMLs on a single host to communicate with each other, but not to
+        the host.
+
+        To use this form of networking, you'll need to run the UML
+        networking daemon on the host.
+
+        For more information, see
+        <http://user-mode-linux.sourceforge.net/networking.html>  That site
+        has examples of the UML command line to use to enable Daemon
+        networking.
+
+        If you'd like to set up a network with other UMLs on a single host,
+        say Y.  If you need a network between UMLs on multiple physical
+        hosts, choose the Multicast Transport.  To set up a network with
+        the host and/or other IP machines, say Y to the Ethertap or Slip
+        transports.  You'll need at least one of them, but may choose
+        more than one without conflict.  If you don't need UML networking,
+        say N.
 
 config UML_NET_MCAST
 	bool "Multicast transport"
 	depends on UML_NET
+	help
+        This Multicast User-Mode Linux network transport allows multiple
+        UMLs (even ones running on different host machines!) to talk to
+        each other over a virtual ethernet network.  However, it requires
+        at least one UML with one of the other transports to act as a
+        bridge if any of them need to be able to talk to their hosts or any
+        other IP machines.
+
+        To use this, your host kernel(s) must support IP Multicasting.
+
+        For more information, see
+        <http://user-mode-linux.sourceforge.net/networking.html>  That site
+        has examples of the UML command line to use to enable Multicast
+        networking, and notes about the security of this approach.
+
+        If you need UMLs on multiple physical hosts to communicate as if
+        they shared an Ethernet network, say Y.  If you need to communicate
+        with other IP machines, make sure you select one of the other
+        transports (possibly in addition to Multicast; they're not
+        exclusive).  If you don't need to network UMLs say N to each of
+        the transports.
 
 config UML_NET_PCAP
 	bool "pcap transport"
 	depends on UML_NET
+	help
+	The pcap transport makes a pcap packet stream on the host look
+	like an ethernet device inside UML.  This is useful for making 
+	UML act as a network monitor for the host.  You must have libcap
+	installed in order to build the pcap transport into UML.
+
+        For more information, see
+        <http://user-mode-linux.sourceforge.net/networking.html>  That site
+        has examples of the UML command line to use to enable this option.
+
+	If you intend to use UML as a network monitor for the host, say
+	Y here.  Otherwise, say N.
+
+config UML_NET_SLIRP
+	bool "SLiRP transport"
+	depends on UML_NET
+	help
+        The SLiRP User-Mode Linux network transport allows a running UML
+        to network by invoking a program that can handle SLIP encapsulated
+        packets.  This is commonly (but not limited to) the application
+        known as SLiRP, a program that can re-socket IP packets back onto
+        the host on which it is run.  Only IP packets are supported,
+        unlike other network transports that can handle all Ethernet
+        frames.  In general, slirp allows the UML the same IP connectivity
+        to the outside world that the host user is permitted, and unlike
+        other transports, SLiRP works without the need of root level
+        privleges, setuid binaries, or SLIP devices on the host.  This
+        also means not every type of connection is possible, but most
+        situations can be accomodated with carefully crafted slirp
+        commands that can be passed along as part of the network device's
+        setup string.  The effect of this transport on the UML is similar
+        that of a host behind a firewall that masquerades all network
+        connections passing through it (but is less secure).
+	
+        To use this you should first have slirp compiled somewhere
+        accessible on the host, and have read its documentation.  If you
+        don't need UML networking, say N.
+	
+        Startup example: "eth0=slirp,FE:FD:01:02:03:04,/usr/local/bin/slirp"
+
 
 # Below are hardware-independent drivers mirrored from
 # drivers/net/Config.in. It would be nice if Linux
diff --git a/arch/um/drivers/Makefile b/arch/um/drivers/Makefile
index bd963ccdc7e8..8e72f9032ab6 100644
--- a/arch/um/drivers/Makefile
+++ b/arch/um/drivers/Makefile
@@ -5,23 +5,14 @@
 
 CHAN_OBJS := chan_kern.o chan_user.o line.o 
 
-# This nonsense is due to kbuild.  In the 2.4 build, I stick -lpcap in 
-# pcap-objs, and that is just included in the link command.  The 2.5 kbuild
-# filters out everything from pcap-objs which are not in the built-in.o
-# dependencies, which are $(obj-y).  So, -lpcap must be in $(obj-y), too.
-# However, make magically expands -lfoo prerequisites into /usr/lib/libfoo.a
-# file names.  This causes the kbuild filtering to filter the -lpcap from
-# pcap-objs, causing the link to fail.
-# So, what this does is figure out by hand (crudely) what file -lpcap really 
-# is and just use it.
-
-PCAP = $(shell for f in echo {/lib,/usr/lib}/libpcap.a; do \
-       [ -f $$f ] && echo $$f ; done | head -1)
+# pcap is broken in 2.5 because kbuild doesn't allow pcap.a to be linked
+# in to pcap.o
 
 slip-objs := slip_kern.o slip_user.o
+slirp-objs := slirp_kern.o slirp_user.o
 daemon-objs := daemon_kern.o daemon_user.o
 mcast-objs := mcast_kern.o mcast_user.o
-pcap-objs := pcap_kern.o pcap_user.o $(PCAP)
+#pcap-objs := pcap_kern.o pcap_user.o $(PCAP)
 net-objs := net_kern.o net_user.o
 mconsole-objs := mconsole_kern.o mconsole_user.o
 hostaudio-objs := hostaudio_kern.o hostaudio_user.o
@@ -34,9 +25,10 @@ export-objs := mconsole_kern.o
 obj-y = 
 obj-$(CONFIG_SSL) += ssl.o 
 obj-$(CONFIG_UML_NET_SLIP) += slip.o
+obj-$(CONFIG_UML_NET_SLIRP) += slirp.o
 obj-$(CONFIG_UML_NET_DAEMON) += daemon.o 
 obj-$(CONFIG_UML_NET_MCAST) += mcast.o 
-obj-$(CONFIG_UML_NET_PCAP) += pcap.o $(PCAP)
+#obj-$(CONFIG_UML_NET_PCAP) += pcap.o $(PCAP)
 obj-$(CONFIG_UML_NET) += net.o 
 obj-$(CONFIG_MCONSOLE) += mconsole.o
 obj-$(CONFIG_MMAPPER) += mmapper_kern.o 
@@ -50,8 +42,6 @@ obj-$(CONFIG_TTY_CHAN) += tty.o
 obj-$(CONFIG_XTERM_CHAN) += xterm.o xterm_kern.o
 obj-$(CONFIG_UML_WATCHDOG) += harddog.o
 
-CFLAGS_pcap_user.o = -I/usr/include/pcap
-
 obj-y += stdio_console.o $(CHAN_OBJS)
 
 USER_SINGLE_OBJS = $(foreach f,$(patsubst %.o,%,$(obj-y) $(obj-m)),$($(f)-objs))
@@ -61,7 +51,7 @@ USER_OBJS := $(filter %_user.o,$(obj-y) $(obj-m) $(USER_SINGLE_OBJS)) fd.o \
 USER_OBJS := $(foreach file,$(USER_OBJS),arch/um/drivers/$(file))
 
 $(USER_OBJS) : %.o: %.c
-	$(CC) $(CFLAGS_$@) $(USER_CFLAGS) -c -o $@ $<
+	$(CC) $(CFLAGS_$(notdir $@)) $(USER_CFLAGS) -c -o $@ $<
 
 clean:
 
diff --git a/arch/um/drivers/net_kern.c b/arch/um/drivers/net_kern.c
index deef1a0a75e3..f6bda1b3b1fe 100644
--- a/arch/um/drivers/net_kern.c
+++ b/arch/um/drivers/net_kern.c
@@ -39,7 +39,6 @@ static int uml_net_rx(struct net_device *dev)
 	/* If we can't allocate memory, try again next round. */
 	if ((skb = dev_alloc_skb(dev->mtu)) == NULL) {
 		lp->stats.rx_dropped++;
-		reactivate_fd(lp->fd, UM_ETH_IRQ);
 		return 0;
 	}
 
@@ -48,7 +47,6 @@ static int uml_net_rx(struct net_device *dev)
 	skb->mac.raw = skb->data;
 	pkt_len = (*lp->read)(lp->fd, &skb, lp);
 
-	reactivate_fd(lp->fd, UM_ETH_IRQ);
 	if (pkt_len > 0) {
 		skb_trim(skb, pkt_len);
 		skb->protocol = (*lp->protocol)(skb);
@@ -69,18 +67,22 @@ void uml_net_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 	struct uml_net_private *lp = dev->priv;
 	int err;
 
-	if (netif_running(dev)) {
-		spin_lock(&lp->lock);
-		while((err = uml_net_rx(dev)) > 0) ;
-		if(err < 0) {
-			printk(KERN_ERR 
-			       "Device '%s' read returned %d, shutting it "
-			       "down\n", dev->name, err);
-			dev->flags &= ~IFF_UP;
-			dev_close(dev);
-		}
-		spin_unlock(&lp->lock);
+	if(!netif_running(dev))
+		return;
+
+	spin_lock(&lp->lock);
+	while((err = uml_net_rx(dev)) > 0) ;
+	if(err < 0) {
+		printk(KERN_ERR 
+		       "Device '%s' read returned %d, shutting it down\n", 
+		       dev->name, err);
+		dev_close(dev);
+		goto out;
 	}
+	reactivate_fd(lp->fd, UM_ETH_IRQ);
+
+ out:
+	spin_unlock(&lp->lock);
 }
 
 static int uml_net_open(struct net_device *dev)
@@ -250,6 +252,37 @@ void uml_net_user_timer_expire(unsigned long _conn)
 #endif
 }
 
+/*
+ * default do nothing hard header packet routines for struct net_device init.
+ * real ethernet transports will overwrite with real routines.
+ */
+static int uml_net_hard_header(struct sk_buff *skb, struct net_device *dev,
+                 unsigned short type, void *daddr, void *saddr, unsigned len)
+{
+	return(0); /* no change */
+}
+
+static int uml_net_rebuild_header(struct sk_buff *skb)
+{
+	return(0); /* ignore */ 
+}
+
+static int uml_net_header_cache(struct neighbour *neigh, struct hh_cache *hh)
+{
+	return(-1); /* fail */
+}
+
+static void uml_net_header_cache_update(struct hh_cache *hh,
+                 struct net_device *dev, unsigned char * haddr)
+{
+	/* ignore */
+}
+
+static int uml_net_header_parse(struct sk_buff *skb, unsigned char *haddr)
+{
+	return(0); /* nothing */
+}
+
 static spinlock_t devices_lock = SPIN_LOCK_UNLOCKED;
 static struct list_head devices = LIST_HEAD_INIT(devices);
 
@@ -261,21 +294,25 @@ static int eth_configure(int n, void *init, char *mac,
 	struct uml_net_private *lp;
 	int save, err, size;
 
+	size = transport->private_size + sizeof(struct uml_net_private) + 
+		sizeof(((struct uml_net_private *) 0)->user);
+
 	device = kmalloc(sizeof(*device), GFP_KERNEL);
 	if(device == NULL){
 		printk(KERN_ERR "eth_configure failed to allocate uml_net\n");
 		return(1);
 	}
 
+	*device = ((struct uml_net) { .list 	= LIST_HEAD_INIT(device->list),
+				      .dev 	= NULL,
+				      .index	= n,
+				      .mac	= { [ 0 ... 5 ] = 0 },
+				      .have_mac	= 0 });
+
 	spin_lock(&devices_lock);
 	list_add(&device->list, &devices);
 	spin_unlock(&devices_lock);
 
-	device->index = n;
-
-	size = transport->private_size + sizeof(struct uml_net_private) + 
-		sizeof(((struct uml_net_private *) 0)->user);
-
 	if(setup_etheraddr(mac, device->mac))
 		device->have_mac = 1;
 
@@ -290,10 +327,18 @@ static int eth_configure(int n, void *init, char *mac,
 		printk(KERN_ERR "eth_configure: failed to allocate device\n");
 		return(1);
 	}
+	memset(dev, 0, sizeof(*dev) + size);
+
 	snprintf(dev->name, sizeof(dev->name), "eth%d", n);
 	dev->priv = (void *) &dev[1];
 	device->dev = dev;
 
+        dev->hard_header = uml_net_hard_header;
+        dev->rebuild_header = uml_net_rebuild_header;
+        dev->hard_header_cache = uml_net_header_cache;
+        dev->header_cache_update= uml_net_header_cache_update;
+        dev->hard_header_parse = uml_net_header_parse;
+
 	(*transport->kern->init)(dev, init);
 
 	dev->mtu = transport->user->max_packet;
@@ -308,32 +353,6 @@ static int eth_configure(int n, void *init, char *mac,
 	dev->do_ioctl = uml_net_ioctl;
 	dev->watchdog_timeo = (HZ >> 1);
 	dev->irq = UM_ETH_IRQ;
-	dev->init = NULL;
-	dev->master = NULL;
-	dev->neigh_setup = NULL;
-	dev->owner = NULL;
-	dev->state = 0;
-	dev->next_sched = 0;
-	dev->get_wireless_stats = 0;
-	dev->wireless_handlers = 0;
-	dev->gflags = 0;
-	dev->mc_list = NULL;
-	dev->mc_count = 0;
-	dev->promiscuity = 0;
-	dev->atalk_ptr = NULL;
-	dev->ip_ptr = NULL;
-	dev->dn_ptr = NULL;
-	dev->ip6_ptr = NULL;
-	dev->ec_ptr = NULL;
-	atomic_set(&dev->refcnt, 0);
-	dev->features = 0;
-	dev->uninit = NULL;
-	dev->destructor = NULL;
-	dev->set_config = NULL;
-	dev->accept_fastpath = 0;
-	dev->br_port = 0;
- 	dev->mem_start = 0;
- 	dev->mem_end = 0;
 
 	rtnl_lock();
 	err = register_netdevice(dev);
@@ -372,6 +391,7 @@ static int eth_configure(int n, void *init, char *mac,
 
 	if(transport->user->init) 
 		(*transport->user->init)(&lp->user, dev);
+
 	if(device->have_mac)
 		set_ether_mac(dev, device->mac);
 	return(0);
@@ -486,7 +506,6 @@ void register_transport(struct transport *new)
 			kfree(init);
 		}
 		list_del(&eth->list);
-		return;
 	}
 }
 
@@ -580,7 +599,7 @@ static int net_remove(char *str)
 	int n;
 
 	n = simple_strtoul(str, &end, 0);
-	if(*end != '\0')
+	if((*end != '\0') || (end == str))
 		return(-1);
 
 	device = find_device(n);
diff --git a/arch/um/drivers/slip.h b/arch/um/drivers/slip.h
index 6fe5588e8a21..495f2f1b1420 100644
--- a/arch/um/drivers/slip.h
+++ b/arch/um/drivers/slip.h
@@ -2,6 +2,9 @@
 #define __UM_SLIP_H
 
 #define BUF_SIZE 1500
+ /* two bytes each for a (pathological) max packet of escaped chars +  * 
+  * terminating END char + initial END char                            */
+#define ENC_BUF_SIZE (2 * BUF_SIZE + 2)
 
 struct slip_data {
 	void *dev;
@@ -9,10 +12,9 @@ struct slip_data {
 	char *addr;
 	char *gate_addr;
 	int slave;
-	/* two bytes each for a (pathological) max packet of escaped chars + 
-	 * terminating END char + inital END char
-	 */
-	char buf[2 * BUF_SIZE + 2];
+	char ibuf[ENC_BUF_SIZE];
+	char obuf[ENC_BUF_SIZE];
+	int more; /* more data: do not read fd until ibuf has been drained */
 	int pos;
 	int esc;
 };
diff --git a/arch/um/drivers/slip_kern.c b/arch/um/drivers/slip_kern.c
index 1ca56f563757..f498a83d9db5 100644
--- a/arch/um/drivers/slip_kern.c
+++ b/arch/um/drivers/slip_kern.c
@@ -1,3 +1,4 @@
+#include "linux/config.h"
 #include "linux/kernel.h"
 #include "linux/stddef.h"
 #include "linux/init.h"
@@ -24,21 +25,19 @@ void slip_init(struct net_device *dev, void *data)
 		{ name :	{ '\0' },
 		  addr:		NULL,
 		  gate_addr :	init->gate_addr,
-		  slave : 	0,
-		  buf : 	{ '\0' },
+		  slave : 	-1,
+		  ibuf : 	{ '\0' },
+		  obuf : 	{ '\0' },
 		  pos :		0,
 		  esc :		0,
 		  dev :		dev });
 
-	strncpy(dev->name, "umn", IFNAMSIZ);
 	dev->init = NULL;
 	dev->hard_header_len = 0;
 	dev->addr_len = 4;
 	dev->type = ARPHRD_ETHER;
 	dev->tx_queue_len = 256;
 	dev->flags = IFF_NOARP;
-	if(register_netdev(dev))
-		printk(KERN_ERR "Couldn't initialize umn\n");
 	printk("SLIP backend - SLIP IP = %s\n", spri->gate_addr);
 }
 
diff --git a/arch/um/drivers/slip_proto.h b/arch/um/drivers/slip_proto.h
new file mode 100644
index 000000000000..7206361ace45
--- /dev/null
+++ b/arch/um/drivers/slip_proto.h
@@ -0,0 +1,93 @@
+/* 
+ * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#ifndef __UM_SLIP_PROTO_H__
+#define __UM_SLIP_PROTO_H__
+
+/* SLIP protocol characters. */
+#define SLIP_END             0300	/* indicates end of frame	*/
+#define SLIP_ESC             0333	/* indicates byte stuffing	*/
+#define SLIP_ESC_END         0334	/* ESC ESC_END means END 'data'	*/
+#define SLIP_ESC_ESC         0335	/* ESC ESC_ESC means ESC 'data'	*/
+
+static inline int slip_unesc(unsigned char c,char *buf,int *pos, int *esc)
+{
+	int ret;
+
+	switch(c){
+	case SLIP_END:
+		*esc = 0;
+		ret=*pos;
+		*pos=0;
+		return(ret);
+	case SLIP_ESC:
+		*esc = 1;
+		return(0);
+	case SLIP_ESC_ESC:
+		if(*esc){
+			*esc = 0;
+			c = SLIP_ESC;
+		}
+		break;
+	case SLIP_ESC_END:
+		if(*esc){
+			*esc = 0;
+			c = SLIP_END;
+		}
+		break;
+	}
+	buf[(*pos)++] = c;
+	return(0);
+}
+
+static inline int slip_esc(unsigned char *s, unsigned char *d, int len)
+{
+	unsigned char *ptr = d;
+	unsigned char c;
+
+	/*
+	 * Send an initial END character to flush out any
+	 * data that may have accumulated in the receiver
+	 * due to line noise.
+	 */
+
+	*ptr++ = SLIP_END;
+
+	/*
+	 * For each byte in the packet, send the appropriate
+	 * character sequence, according to the SLIP protocol.
+	 */
+
+	while (len-- > 0) {
+		switch(c = *s++) {
+		case SLIP_END:
+			*ptr++ = SLIP_ESC;
+			*ptr++ = SLIP_ESC_END;
+			break;
+		case SLIP_ESC:
+			*ptr++ = SLIP_ESC;
+			*ptr++ = SLIP_ESC_ESC;
+			break;
+		default:
+			*ptr++ = c;
+			break;
+		}
+	}
+	*ptr++ = SLIP_END;
+	return (ptr - d);
+}
+
+#endif
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only.  This must remain at the end
+ * of the file.
+ * ---------------------------------------------------------------------------
+ * Local variables:
+ * c-file-style: "linux"
+ * End:
+ */
diff --git a/arch/um/drivers/slip_user.c b/arch/um/drivers/slip_user.c
index d8cd43c2f555..e36e8213671b 100644
--- a/arch/um/drivers/slip_user.c
+++ b/arch/um/drivers/slip_user.c
@@ -15,6 +15,7 @@
 #include "user.h"
 #include "net_user.h"
 #include "slip.h"
+#include "slip_proto.h"
 #include "helper.h"
 #include "os.h"
 
@@ -66,7 +67,7 @@ static void slip_pre_exec(void *arg)
 
 	if(data->stdin != -1) dup2(data->stdin, 0);
 	dup2(data->stdout, 1);
-	close(data->close_me);
+	if(data->close_me != -1) close(data->close_me);
 }
 
 static int slip_tramp(char **argv, int fd)
@@ -156,7 +157,7 @@ static int slip_open(void *data)
 		}
 		sencap = 0;
 		if(ioctl(sfd, SIOCSIFENCAP, &sencap) < 0){
-			printk("Failed to sett slip encapsulation - "
+			printk("Failed to set slip encapsulation - "
 			       "errno = %d\n", errno);
 			return(-errno);
 		}
@@ -186,103 +187,48 @@ static void slip_close(int fd, void *data)
 	pri->slave = -1;
 }
 
-/* SLIP protocol characters. */
-#define END             0300		/* indicates end of frame	*/
-#define ESC             0333		/* indicates byte stuffing	*/
-#define ESC_END         0334		/* ESC ESC_END means END 'data'	*/
-#define ESC_ESC         0335		/* ESC ESC_ESC means ESC 'data'	*/
-
-static int slip_unesc(struct slip_data *sl, unsigned char c)
-{
-	int ret;
-
-	switch(c){
-	case END:
-		sl->esc = 0;
-		ret = sl->pos;
-		sl->pos = 0;
-		return(ret);
-	case ESC:
-		sl->esc = 1;
-		return(0);
-	case ESC_ESC:
-		if(sl->esc){
-			sl->esc = 0;
-			c = ESC;
-		}
-		break;
-	case ESC_END:
-		if(sl->esc){
-			sl->esc = 0;
-			c = END;
-		}
-		break;
-	}
-	sl->buf[sl->pos++] = c;
-	return(0);
-}
-
 int slip_user_read(int fd, void *buf, int len, struct slip_data *pri)
 {
 	int i, n, size, start;
 
-	n = net_read(fd, &pri->buf[pri->pos], sizeof(pri->buf) - pri->pos);
+	if(pri->more>0) {
+		i = 0;
+		while(i < pri->more) {
+			size = slip_unesc(pri->ibuf[i++],
+					pri->ibuf, &pri->pos, &pri->esc);
+			if(size){
+				memcpy(buf, pri->ibuf, size);
+				memmove(pri->ibuf, &pri->ibuf[i], pri->more-i);
+				pri->more=pri->more-i; 
+				return(size);
+			}
+		}
+		pri->more=0;
+	}
+
+	n = net_read(fd, &pri->ibuf[pri->pos], sizeof(pri->ibuf) - pri->pos);
 	if(n <= 0) return(n);
 
 	start = pri->pos;
 	for(i = 0; i < n; i++){
-		size = slip_unesc(pri, pri->buf[start + i]);
+		size = slip_unesc(pri->ibuf[start + i],
+				pri->ibuf, &pri->pos, &pri->esc);
 		if(size){
-			memcpy(buf, pri->buf, size);
+			memcpy(buf, pri->ibuf, size);
+			memmove(pri->ibuf, &pri->ibuf[start+i+1], n-(i+1));
+			pri->more=n-(i+1); 
 			return(size);
 		}
 	}
 	return(0);
 }
 
-static int slip_esc(unsigned char *s, unsigned char *d, int len)
-{
-	unsigned char *ptr = d;
-	unsigned char c;
-
-	/*
-	 * Send an initial END character to flush out any
-	 * data that may have accumulated in the receiver
-	 * due to line noise.
-	 */
-
-	*ptr++ = END;
-
-	/*
-	 * For each byte in the packet, send the appropriate
-	 * character sequence, according to the SLIP protocol.
-	 */
-
-	while (len-- > 0) {
-		switch(c = *s++) {
-		case END:
-			*ptr++ = ESC;
-			*ptr++ = ESC_END;
-			break;
-		case ESC:
-			*ptr++ = ESC;
-			*ptr++ = ESC_ESC;
-			break;
-		default:
-			*ptr++ = c;
-			break;
-		}
-	}
-	*ptr++ = END;
-	return (ptr - d);
-}
-
 int slip_user_write(int fd, void *buf, int len, struct slip_data *pri)
 {
 	int actual, n;
 
-	actual = slip_esc(buf, pri->buf, len);
-	n = net_write(fd, pri->buf, actual);
+	actual = slip_esc(buf, pri->obuf, len);
+	n = net_write(fd, pri->obuf, actual);
 	if(n < 0) return(n);
 	else return(len);
 }
diff --git a/arch/um/drivers/slirp.h b/arch/um/drivers/slirp.h
new file mode 100644
index 000000000000..04e407d1e44a
--- /dev/null
+++ b/arch/um/drivers/slirp.h
@@ -0,0 +1,51 @@
+#ifndef __UM_SLIRP_H
+#define __UM_SLIRP_H
+
+#define BUF_SIZE 1500
+ /* two bytes each for a (pathological) max packet of escaped chars +  * 
+  * terminating END char + initial END char                            */
+#define ENC_BUF_SIZE (2 * BUF_SIZE + 2)
+
+#define SLIRP_MAX_ARGS 100
+/*
+ * XXX this next definition is here because I don't understand why this
+ * initializer doesn't work in slirp_kern.c:
+ *
+ *   argv :  { init->argv[ 0 ... SLIRP_MAX_ARGS-1 ] },
+ *
+ * or why I can't typecast like this:
+ *
+ *   argv :  (char* [SLIRP_MAX_ARGS])(init->argv), 
+ */
+struct arg_list_dummy_wrapper { char *argv[SLIRP_MAX_ARGS]; };
+
+struct slirp_data {
+	void *dev;
+	struct arg_list_dummy_wrapper argw;
+	int pid;
+	int slave;
+	char ibuf[ENC_BUF_SIZE];
+	char obuf[ENC_BUF_SIZE];
+	int more; /* more data: do not read fd until ibuf has been drained */
+	int pos;
+	int esc;
+};
+
+extern struct net_user_info slirp_user_info;
+
+extern int set_umn_addr(int fd, char *addr, char *ptp_addr);
+extern int slirp_user_read(int fd, void *buf, int len, struct slirp_data *pri);
+extern int slirp_user_write(int fd, void *buf, int len, struct slirp_data *pri);
+
+#endif
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only.  This must remain at the end
+ * of the file.
+ * ---------------------------------------------------------------------------
+ * Local variables:
+ * c-file-style: "linux"
+ * End:
+ */
diff --git a/arch/um/drivers/slirp_kern.c b/arch/um/drivers/slirp_kern.c
new file mode 100644
index 000000000000..1a459dd94d76
--- /dev/null
+++ b/arch/um/drivers/slirp_kern.c
@@ -0,0 +1,132 @@
+#include "linux/kernel.h"
+#include "linux/stddef.h"
+#include "linux/init.h"
+#include "linux/netdevice.h"
+#include "linux/if_arp.h"
+#include "net_kern.h"
+#include "net_user.h"
+#include "kern.h"
+#include "slirp.h"
+
+struct slirp_init {
+	struct arg_list_dummy_wrapper argw;  /* XXX should be simpler... */
+};
+
+void slirp_init(struct net_device *dev, void *data)
+{
+	struct uml_net_private *private;
+	struct slirp_data *spri;
+	struct slirp_init *init = data;
+	int i;
+
+	private = dev->priv;
+	spri = (struct slirp_data *) private->user;
+	*spri = ((struct slirp_data)
+		{ argw :	init->argw,
+		  pid : 	-1,
+		  slave : 	-1,
+		  ibuf : 	{ '\0' },
+		  obuf : 	{ '\0' },
+		  pos :		0,
+		  esc :		0,
+		  dev :		dev });
+
+	dev->init = NULL;
+	dev->hard_header_len = 0;
+	dev->addr_len = 4;
+	dev->type = ARPHRD_ETHER;
+	dev->tx_queue_len = 256;
+	dev->flags = IFF_NOARP;
+	printk("SLIRP backend - command line:");
+	for(i=0;spri->argw.argv[i]!=NULL;i++) {
+		printk(" '%s'",spri->argw.argv[i]);
+	}
+	printk("\n");
+}
+
+static unsigned short slirp_protocol(struct sk_buff *skbuff)
+{
+	return(htons(ETH_P_IP));
+}
+
+static int slirp_read(int fd, struct sk_buff **skb, 
+		       struct uml_net_private *lp)
+{
+	return(slirp_user_read(fd, (*skb)->mac.raw, (*skb)->dev->mtu, 
+			      (struct slirp_data *) &lp->user));
+}
+
+static int slirp_write(int fd, struct sk_buff **skb,
+		      struct uml_net_private *lp)
+{
+	return(slirp_user_write(fd, (*skb)->data, (*skb)->len, 
+			       (struct slirp_data *) &lp->user));
+}
+
+struct net_kern_info slirp_kern_info = {
+	init:			slirp_init,
+	protocol:		slirp_protocol,
+	read:			slirp_read,
+	write:			slirp_write,
+};
+
+static int slirp_setup(char *str, char **mac_out, void *data)
+{
+	struct slirp_init *init = data;
+	int i=0;
+
+	*init = ((struct slirp_init)
+		{ argw :		{ { "slirp", NULL  } } });
+
+	str = split_if_spec(str, mac_out, NULL);
+
+	if(str == NULL) { /* no command line given after MAC addr */
+		return(1);
+	}
+
+	do {
+		if(i>=SLIRP_MAX_ARGS-1) {
+			printk("slirp_setup: truncating slirp arguments\n");
+			break;
+		}
+		init->argw.argv[i++] = str;
+		while(*str && *str!=',') {
+			if(*str=='_') *str=' ';
+			str++;
+		}
+		if(*str!=',')
+			break;
+		*str++='\0';
+	} while(1);
+	init->argw.argv[i]=NULL;
+	return(1);
+}
+
+static struct transport slirp_transport = {
+	list :		LIST_HEAD_INIT(slirp_transport.list),
+	name :		"slirp",
+	setup : 	slirp_setup,
+	user :		&slirp_user_info,
+	kern :		&slirp_kern_info,
+	private_size :	sizeof(struct slirp_data),
+	setup_size :	sizeof(struct slirp_init),
+};
+
+static int register_slirp(void)
+{
+	register_transport(&slirp_transport);
+	return(1);
+}
+
+__initcall(register_slirp);
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only.  This must remain at the end
+ * of the file.
+ * ---------------------------------------------------------------------------
+ * Local variables:
+ * c-file-style: "linux"
+ * End:
+ */
diff --git a/arch/um/drivers/slirp_user.c b/arch/um/drivers/slirp_user.c
new file mode 100644
index 000000000000..bba76df0f33d
--- /dev/null
+++ b/arch/um/drivers/slirp_user.c
@@ -0,0 +1,202 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stddef.h>
+#include <sched.h>
+#include <string.h>
+#include <sys/fcntl.h>
+#include <sys/errno.h>
+#include <sys/wait.h>
+#include <sys/signal.h>
+#include "user_util.h"
+#include "kern_util.h"
+#include "user.h"
+#include "net_user.h"
+#include "slirp.h"
+#include "slip_proto.h"
+#include "helper.h"
+#include "os.h"
+
+void slirp_user_init(void *data, void *dev)
+{
+	struct slirp_data *pri = data;
+
+	pri->dev = dev;
+}
+
+struct slirp_pre_exec_data {
+	int stdin;
+	int stdout;
+};
+
+static void slirp_pre_exec(void *arg)
+{
+	struct slirp_pre_exec_data *data = arg;
+
+	if(data->stdin != -1) dup2(data->stdin, 0);
+	if(data->stdout != -1) dup2(data->stdout, 1);
+}
+
+static int slirp_tramp(char **argv, int fd)
+{
+	struct slirp_pre_exec_data pe_data;
+	int pid;
+
+	pe_data.stdin = fd;
+	pe_data.stdout = fd;
+	pid = run_helper(slirp_pre_exec, &pe_data, argv, NULL);
+
+	return(pid);
+}
+ 
+static int slirp_datachan(int *mfd, int *sfd)
+{
+	int fds[2], err;
+
+	err = os_pipe(fds, 1, 1);
+	if(err){
+		printk("slirp_datachan: Failed to open pipe, errno = %d\n",
+		       -err);
+		return(err);
+	}
+
+	*mfd = fds[0];
+	*sfd = fds[1];
+	return(0);
+}
+
+static int slirp_open(void *data)
+{
+	struct slirp_data *pri = data;
+	int sfd, mfd, pid, err;
+
+	err = slirp_datachan(&mfd, &sfd);
+	if(err)
+		return(err);
+
+	pid = slirp_tramp(pri->argw.argv, sfd);
+
+	if(pid < 0){
+		printk("slirp_tramp failed - errno = %d\n", pid);
+		os_close_file(sfd);	
+		os_close_file(mfd);	
+		return(pid);
+	}
+
+	pri->slave = sfd;
+	pri->pos = 0;
+	pri->esc = 0;
+
+	pri->pid = pid;
+
+	return(mfd);
+}
+
+static void slirp_close(int fd, void *data)
+{
+	struct slirp_data *pri = data;
+	int status,err;
+
+	close(fd);
+	close(pri->slave);
+
+	pri->slave = -1;
+
+	if(pri->pid<1) {
+		printk("slirp_close: no child process to shut down\n");
+		return;
+	}
+
+#if 0
+	if(kill(pri->pid, SIGHUP)<0) {
+		printk("slirp_close: sending hangup to %d failed (%d)\n",
+			pri->pid, errno);
+	}
+#endif
+
+	err = waitpid(pri->pid, &status, WNOHANG);
+	if(err<0) {
+		printk("slirp_close: waitpid returned %d\n", errno);
+		return;
+	}
+
+	if(err==0) {
+		printk("slirp_close: process %d has not exited\n");
+		return;
+	}
+
+	pri->pid = -1;
+}
+
+int slirp_user_read(int fd, void *buf, int len, struct slirp_data *pri)
+{
+	int i, n, size, start;
+
+	if(pri->more>0) {
+		i = 0;
+		while(i < pri->more) {
+			size = slip_unesc(pri->ibuf[i++],
+					pri->ibuf,&pri->pos,&pri->esc);
+			if(size){
+				memcpy(buf, pri->ibuf, size);
+				memmove(pri->ibuf, &pri->ibuf[i], pri->more-i);
+				pri->more=pri->more-i; 
+				return(size);
+			}
+		}
+		pri->more=0;
+	}
+
+	n = net_read(fd, &pri->ibuf[pri->pos], sizeof(pri->ibuf) - pri->pos);
+	if(n <= 0) return(n);
+
+	start = pri->pos;
+	for(i = 0; i < n; i++){
+		size = slip_unesc(pri->ibuf[start + i],
+				pri->ibuf,&pri->pos,&pri->esc);
+		if(size){
+			memcpy(buf, pri->ibuf, size);
+			memmove(pri->ibuf, &pri->ibuf[start+i+1], n-(i+1));
+			pri->more=n-(i+1); 
+			return(size);
+		}
+	}
+	return(0);
+}
+
+int slirp_user_write(int fd, void *buf, int len, struct slirp_data *pri)
+{
+	int actual, n;
+
+	actual = slip_esc(buf, pri->obuf, len);
+	n = net_write(fd, pri->obuf, actual);
+	if(n < 0) return(n);
+	else return(len);
+}
+
+static int slirp_set_mtu(int mtu, void *data)
+{
+	return(mtu);
+}
+
+struct net_user_info slirp_user_info = {
+	init:		slirp_user_init,
+	open:		slirp_open,
+	close:	 	slirp_close,
+	remove:	 	NULL,
+	set_mtu:	slirp_set_mtu,
+	add_address:	NULL,
+	delete_address: NULL,
+	max_packet:	BUF_SIZE
+};
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only.  This must remain at the end
+ * of the file.
+ * ---------------------------------------------------------------------------
+ * Local variables:
+ * c-file-style: "linux"
+ * End:
+ */
diff --git a/arch/um/include/net_kern.h b/arch/um/include/net_kern.h
index 22d43acb78f1..de793e9bf438 100644
--- a/arch/um/include/net_kern.h
+++ b/arch/um/include/net_kern.h
@@ -1,3 +1,8 @@
+/* 
+ * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
 #ifndef __UM_NET_KERN_H
 #define __UM_NET_KERN_H
 
diff --git a/arch/um/include/net_user.h b/arch/um/include/net_user.h
index 01867cae92e2..36807b796e9f 100644
--- a/arch/um/include/net_user.h
+++ b/arch/um/include/net_user.h
@@ -1,3 +1,8 @@
+/* 
+ * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
 #ifndef __UM_NET_USER_H__
 #define __UM_NET_USER_H__