[PATCH 2/3] UML - Network driver MTU cleanups

From: Jeff Dike
Date: Wed Sep 26 2007 - 17:46:54 EST

A bunch of MTU-related cleanups in the network code.

First, there is the addition of the notion of a maximally-sized
packet, which is the MTU plus headers. This is used to size the skb
that will receive a packet. This allows ether_adjust_skb to go away,
as it was used to resize the skb after it was allocated.

Since the skb passed into the low-level read routine is no longer
resized, and possibly reallocated, there, they (and the write
routines) don't need to get an sk_buff **. They just need the sk_buff
* now. The callers of ether_adjust_skb still need to do the skb_put,
so that's now inlined.

The MAX_PACKET definitions in most of the drivers are gone.

The set_mtu methods were all the same and did nothing, so they can be
removed.

The ethertap driver had a typo which doubled the size of the packet
rather than adding two bytes to it. It also wasn't defining its
setup_size, causing a zero-byte kmalloc and crash when the invalid
pointer returned from kmalloc was dereferenced.

Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxxxxxx>
---
arch/um/drivers/daemon_kern.c | 15 +++--------
arch/um/drivers/daemon_user.c | 11 +-------
arch/um/drivers/mcast_kern.c | 13 +++------
arch/um/drivers/mcast_user.c | 11 +-------
arch/um/drivers/net_kern.c | 42 +++++--------------------------
arch/um/drivers/pcap_kern.c | 13 ++-------
arch/um/drivers/pcap_user.c | 9 ++----
arch/um/drivers/slip_kern.c | 10 ++-----
arch/um/drivers/slip_user.c | 9 +-----
arch/um/drivers/slirp_kern.c | 14 ++++------
arch/um/drivers/slirp_user.c | 9 +-----
arch/um/drivers/vde_kern.c | 19 +++++---------
arch/um/drivers/vde_user.c | 11 +-------
arch/um/include/net_kern.h | 13 ++++-----
arch/um/include/net_user.h | 4 +-
arch/um/os-Linux/drivers/ethertap_kern.c | 30 +++++++---------------
arch/um/os-Linux/drivers/ethertap_user.c | 9 +-----
arch/um/os-Linux/drivers/tuntap_kern.c | 15 +++--------
arch/um/os-Linux/drivers/tuntap_user.c | 11 +-------
19 files changed, 80 insertions(+), 188 deletions(-)

Index: linux-2.6.20/arch/um/drivers/daemon_user.c
===================================================================
--- linux-2.6.20.orig/arch/um/drivers/daemon_user.c 2007-09-26 17:14:22.000000000 -0400
+++ linux-2.6.20/arch/um/drivers/daemon_user.c 2007-09-26 17:19:31.000000000 -0400
@@ -19,8 +19,6 @@
#include "um_malloc.h"
#include "user.h"

-#define MAX_PACKET (ETH_MAX_PACKET + ETH_HEADER_OTHER)
-
enum request_type { REQ_NEW_CONTROL };

#define SWITCH_MAGIC 0xfeedface
@@ -184,18 +182,13 @@ int daemon_user_write(int fd, void *buf,
return net_sendto(fd, buf, len, data_addr, sizeof(*data_addr));
}

-static int daemon_set_mtu(int mtu, void *data)
-{
- return mtu;
-}
-
const struct net_user_info daemon_user_info = {
.init = daemon_user_init,
.open = daemon_open,
.close = NULL,
.remove = daemon_remove,
- .set_mtu = daemon_set_mtu,
.add_address = NULL,
.delete_address = NULL,
- .max_packet = MAX_PACKET - ETH_HEADER_OTHER
+ .mtu = ETH_MAX_PACKET,
+ .max_packet = ETH_MAX_PACKET + ETH_HEADER_OTHER,
};
Index: linux-2.6.20/arch/um/drivers/mcast_user.c
===================================================================
--- linux-2.6.20.orig/arch/um/drivers/mcast_user.c 2007-09-26 17:14:22.000000000 -0400
+++ linux-2.6.20/arch/um/drivers/mcast_user.c 2007-09-26 17:19:31.000000000 -0400
@@ -20,8 +20,6 @@
#include "um_malloc.h"
#include "user.h"

-#define MAX_PACKET (ETH_MAX_PACKET + ETH_HEADER_OTHER)
-
static struct sockaddr_in *new_addr(char *addr, unsigned short port)
{
struct sockaddr_in *sin;
@@ -154,18 +152,13 @@ int mcast_user_write(int fd, void *buf,
return net_sendto(fd, buf, len, data_addr, sizeof(*data_addr));
}

-static int mcast_set_mtu(int mtu, void *data)
-{
- return mtu;
-}
-
const struct net_user_info mcast_user_info = {
.init = mcast_user_init,
.open = mcast_open,
.close = mcast_close,
.remove = mcast_remove,
- .set_mtu = mcast_set_mtu,
.add_address = NULL,
.delete_address = NULL,
- .max_packet = MAX_PACKET - ETH_HEADER_OTHER
+ .mtu = ETH_MAX_PACKET,
+ .max_packet = ETH_MAX_PACKET + ETH_HEADER_OTHER,
};
Index: linux-2.6.20/arch/um/drivers/pcap_user.c
===================================================================
--- linux-2.6.20.orig/arch/um/drivers/pcap_user.c 2007-09-26 17:14:22.000000000 -0400
+++ linux-2.6.20/arch/um/drivers/pcap_user.c 2007-09-26 17:19:31.000000000 -0400
@@ -13,8 +13,6 @@
#include "um_malloc.h"
#include "user.h"

-#define MAX_PACKET (ETH_MAX_PACKET + ETH_HEADER_OTHER)
-
#define PCAP_FD(p) (*(int *)(p))

static int pcap_user_init(void *data, void *dev)
@@ -23,7 +21,8 @@ static int pcap_user_init(void *data, vo
pcap_t *p;
char errors[PCAP_ERRBUF_SIZE];

- p = pcap_open_live(pri->host_if, MAX_PACKET, pri->promisc, 0, errors);
+ p = pcap_open_live(pri->host_if, ETH_MAX_PACKET + ETH_HEADER_OTHER,
+ pri->promisc, 0, errors);
if (p == NULL) {
printk(UM_KERN_ERR "pcap_user_init : pcap_open_live failed - "
"'%s'\n", errors);
@@ -133,8 +132,8 @@ const struct net_user_info pcap_user_inf
.open = pcap_open,
.close = NULL,
.remove = pcap_remove,
- .set_mtu = NULL,
.add_address = NULL,
.delete_address = NULL,
- .max_packet = MAX_PACKET - ETH_HEADER_OTHER
+ .mtu = ETH_MAX_PACKET,
+ .max_packet = ETH_MAX_PACKET + ETH_HEADER_OTHER,
};
Index: linux-2.6.20/arch/um/drivers/slip_user.c
===================================================================
--- linux-2.6.20.orig/arch/um/drivers/slip_user.c 2007-09-26 17:14:22.000000000 -0400
+++ linux-2.6.20/arch/um/drivers/slip_user.c 2007-09-26 17:19:31.000000000 -0400
@@ -230,11 +230,6 @@ int slip_user_write(int fd, void *buf, i
return slip_proto_write(fd, buf, len, &pri->slip);
}

-static int slip_set_mtu(int mtu, void *data)
-{
- return mtu;
-}
-
static void slip_add_addr(unsigned char *addr, unsigned char *netmask,
void *data)
{
@@ -260,8 +255,8 @@ const struct net_user_info slip_user_inf
.open = slip_open,
.close = slip_close,
.remove = NULL,
- .set_mtu = slip_set_mtu,
.add_address = slip_add_addr,
.delete_address = slip_del_addr,
- .max_packet = BUF_SIZE
+ .mtu = BUF_SIZE,
+ .max_packet = BUF_SIZE,
};
Index: linux-2.6.20/arch/um/drivers/slirp_user.c
===================================================================
--- linux-2.6.20.orig/arch/um/drivers/slirp_user.c 2007-09-26 17:14:22.000000000 -0400
+++ linux-2.6.20/arch/um/drivers/slirp_user.c 2007-09-26 17:19:31.000000000 -0400
@@ -124,18 +124,13 @@ int slirp_user_write(int fd, void *buf,
return slip_proto_write(fd, buf, len, &pri->slip);
}

-static int slirp_set_mtu(int mtu, void *data)
-{
- return mtu;
-}
-
const 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
+ .mtu = BUF_SIZE,
+ .max_packet = BUF_SIZE,
};
Index: linux-2.6.20/arch/um/drivers/vde_user.c
===================================================================
--- linux-2.6.20.orig/arch/um/drivers/vde_user.c 2007-09-26 17:14:22.000000000 -0400
+++ linux-2.6.20/arch/um/drivers/vde_user.c 2007-09-26 17:19:31.000000000 -0400
@@ -12,8 +12,6 @@
#include "user.h"
#include "vde.h"

-#define MAX_PACKET (ETH_MAX_PACKET + ETH_HEADER_OTHER)
-
static int vde_user_init(void *data, void *dev)
{
struct vde_data *pri = data;
@@ -65,20 +63,15 @@ static void vde_remove(void *data)
printk(UM_KERN_WARNING "vde_remove - we have no VDECONN to remove");
}

-static int vde_set_mtu(int mtu, void *data)
-{
- return mtu;
-}
-
const struct net_user_info vde_user_info = {
.init = vde_user_init,
.open = vde_user_open,
.close = NULL,
.remove = vde_remove,
- .set_mtu = vde_set_mtu,
.add_address = NULL,
.delete_address = NULL,
- .max_packet = MAX_PACKET - ETH_HEADER_OTHER
+ .mtu = ETH_MAX_PACKET,
+ .max_packet = ETH_MAX_PACKET + ETH_HEADER_OTHER,
};

void vde_init_libstuff(struct vde_data *vpri, struct vde_init *init)
Index: linux-2.6.20/arch/um/os-Linux/drivers/ethertap_user.c
===================================================================
--- linux-2.6.20.orig/arch/um/os-Linux/drivers/ethertap_user.c 2007-09-26 17:14:23.000000000 -0400
+++ linux-2.6.20/arch/um/os-Linux/drivers/ethertap_user.c 2007-09-26 17:19:31.000000000 -0400
@@ -222,11 +222,6 @@ static void etap_close(int fd, void *dat
pri->control_fd = -1;
}

-static int etap_set_mtu(int mtu, void *data)
-{
- return mtu;
-}
-
static void etap_add_addr(unsigned char *addr, unsigned char *netmask,
void *data)
{
@@ -254,8 +249,8 @@ const struct net_user_info ethertap_user
.open = etap_open,
.close = etap_close,
.remove = NULL,
- .set_mtu = etap_set_mtu,
.add_address = etap_add_addr,
.delete_address = etap_del_addr,
- .max_packet = MAX_PACKET - ETH_HEADER_ETHERTAP
+ .mtu = ETH_MAX_PACKET,
+ .max_packet = ETH_MAX_PACKET + ETH_HEADER_ETHERTAP,
};
Index: linux-2.6.20/arch/um/os-Linux/drivers/tuntap_user.c
===================================================================
--- linux-2.6.20.orig/arch/um/os-Linux/drivers/tuntap_user.c 2007-09-26 17:14:23.000000000 -0400
+++ linux-2.6.20/arch/um/os-Linux/drivers/tuntap_user.c 2007-09-26 17:19:31.000000000 -0400
@@ -18,8 +18,6 @@
#include "tuntap.h"
#include "user.h"

-#define MAX_PACKET ETH_MAX_PACKET
-
static int tuntap_user_init(void *data, void *dev)
{
struct tuntap_data *pri = data;
@@ -206,18 +204,13 @@ static void tuntap_close(int fd, void *d
pri->fd = -1;
}

-static int tuntap_set_mtu(int mtu, void *data)
-{
- return mtu;
-}
-
const struct net_user_info tuntap_user_info = {
.init = tuntap_user_init,
.open = tuntap_open,
.close = tuntap_close,
.remove = NULL,
- .set_mtu = tuntap_set_mtu,
.add_address = tuntap_add_addr,
.delete_address = tuntap_del_addr,
- .max_packet = MAX_PACKET
+ .mtu = ETH_MAX_PACKET,
+ .max_packet = ETH_MAX_PACKET + ETH_HEADER_OTHER,
};
Index: linux-2.6.20/arch/um/drivers/net_kern.c
===================================================================
--- linux-2.6.20.orig/arch/um/drivers/net_kern.c 2007-09-26 17:14:22.000000000 -0400
+++ linux-2.6.20/arch/um/drivers/net_kern.c 2007-09-26 17:19:31.000000000 -0400
@@ -41,16 +41,16 @@ static int uml_net_rx(struct net_device
struct sk_buff *skb;

/* If we can't allocate memory, try again next round. */
- skb = dev_alloc_skb(dev->mtu);
+ skb = dev_alloc_skb(lp->max_packet);
if (skb == NULL) {
lp->stats.rx_dropped++;
return 0;
}

skb->dev = dev;
- skb_put(skb, dev->mtu);
+ skb_put(skb, lp->max_packet);
skb_reset_mac_header(skb);
- pkt_len = (*lp->read)(lp->fd, &skb, lp);
+ pkt_len = (*lp->read)(lp->fd, skb, lp);

if (pkt_len > 0) {
skb_trim(skb, pkt_len);
@@ -178,7 +178,7 @@ static int uml_net_start_xmit(struct sk_

spin_lock_irqsave(&lp->lock, flags);

- len = (*lp->write)(lp->fd, &skb, lp);
+ len = (*lp->write)(lp->fd, skb, lp);

if (len == skb->len) {
lp->stats.tx_packets++;
@@ -240,22 +240,9 @@ static int uml_net_set_mac(struct net_de

static int uml_net_change_mtu(struct net_device *dev, int new_mtu)
{
- struct uml_net_private *lp = dev->priv;
- int err = 0;
-
- spin_lock_irq(&lp->lock);
-
- new_mtu = (*lp->set_mtu)(new_mtu, &lp->user);
- if (new_mtu < 0) {
- err = new_mtu;
- goto out;
- }
-
dev->mtu = new_mtu;

- out:
- spin_unlock_irq(&lp->lock);
- return err;
+ return 0;
}

static void uml_net_get_drvinfo(struct net_device *dev,
@@ -427,6 +414,7 @@ static void eth_configure(int n, void *i
.dev = dev,
.fd = -1,
.mac = { 0xfe, 0xfd, 0x0, 0x0, 0x0, 0x0},
+ .max_packet = transport->user->max_packet,
.protocol = transport->kern->protocol,
.open = transport->user->open,
.close = transport->user->close,
@@ -434,8 +422,7 @@ static void eth_configure(int n, void *i
.read = transport->kern->read,
.write = transport->kern->write,
.add_address = transport->user->add_address,
- .delete_address = transport->user->delete_address,
- .set_mtu = transport->user->set_mtu });
+ .delete_address = transport->user->delete_address });

init_timer(&lp->tl);
spin_lock_init(&lp->lock);
@@ -447,7 +434,7 @@ static void eth_configure(int n, void *i
goto out_unregister;

set_ether_mac(dev, device->mac);
- dev->mtu = transport->user->max_packet;
+ dev->mtu = transport->user->mtu;
dev->open = uml_net_open;
dev->hard_start_xmit = uml_net_start_xmit;
dev->stop = uml_net_close;
@@ -807,19 +794,6 @@ static void close_devices(void)

__uml_exitcall(close_devices);

-struct sk_buff *ether_adjust_skb(struct sk_buff *skb, int extra)
-{
- if ((skb != NULL) && (skb_tailroom(skb) < extra)) {
- struct sk_buff *skb2;
-
- skb2 = skb_copy_expand(skb, 0, extra, GFP_ATOMIC);
- dev_kfree_skb(skb);
- skb = skb2;
- }
- if (skb != NULL) skb_put(skb, extra);
- return skb;
-}
-
void iter_addresses(void *d, void (*cb)(unsigned char *, unsigned char *,
void *),
void *arg)
Index: linux-2.6.20/arch/um/include/net_user.h
===================================================================
--- linux-2.6.20.orig/arch/um/include/net_user.h 2007-09-26 17:14:23.000000000 -0400
+++ linux-2.6.20/arch/um/include/net_user.h 2007-09-26 17:19:31.000000000 -0400
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2002 Jeff Dike (jdike@xxxxxxxxxx)
+ * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/

@@ -18,10 +18,10 @@ struct net_user_info {
int (*open)(void *);
void (*close)(int, void *);
void (*remove)(void *);
- int (*set_mtu)(int mtu, void *);
void (*add_address)(unsigned char *, unsigned char *, void *);
void (*delete_address)(unsigned char *, unsigned char *, void *);
int max_packet;
+ int mtu;
};

extern void ether_user_init(void *data, void *dev);
Index: linux-2.6.20/arch/um/drivers/daemon_kern.c
===================================================================
--- linux-2.6.20.orig/arch/um/drivers/daemon_kern.c 2007-09-26 17:14:32.000000000 -0400
+++ linux-2.6.20/arch/um/drivers/daemon_kern.c 2007-09-26 17:19:31.000000000 -0400
@@ -39,20 +39,15 @@ static void daemon_init(struct net_devic
printk("\n");
}

-static int daemon_read(int fd, struct sk_buff **skb,
- struct uml_net_private *lp)
+static int daemon_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
- *skb = ether_adjust_skb(*skb, ETH_HEADER_OTHER);
- if (*skb == NULL)
- return -ENOMEM;
- return net_recvfrom(fd, skb_mac_header(*skb),
- (*skb)->dev->mtu + ETH_HEADER_OTHER);
+ return net_recvfrom(fd, skb_mac_header(skb),
+ skb->dev->mtu + ETH_HEADER_OTHER);
}

-static int daemon_write(int fd, struct sk_buff **skb,
- struct uml_net_private *lp)
+static int daemon_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
- return daemon_user_write(fd, (*skb)->data, (*skb)->len,
+ return daemon_user_write(fd, skb->data, skb->len,
(struct daemon_data *) &lp->user);
}

Index: linux-2.6.20/arch/um/drivers/mcast_kern.c
===================================================================
--- linux-2.6.20.orig/arch/um/drivers/mcast_kern.c 2007-09-26 17:15:11.000000000 -0400
+++ linux-2.6.20/arch/um/drivers/mcast_kern.c 2007-09-26 17:19:31.000000000 -0400
@@ -39,18 +39,15 @@ static void mcast_init(struct net_device
dpri->addr, dpri->port, dpri->ttl);
}

-static int mcast_read(int fd, struct sk_buff **skb, struct uml_net_private *lp)
+static int mcast_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
- *skb = ether_adjust_skb(*skb, ETH_HEADER_OTHER);
- if (*skb == NULL)
- return -ENOMEM;
- return net_recvfrom(fd, skb_mac_header(*skb),
- (*skb)->dev->mtu + ETH_HEADER_OTHER);
+ return net_recvfrom(fd, skb_mac_header(skb),
+ skb->dev->mtu + ETH_HEADER_OTHER);
}

-static int mcast_write(int fd, struct sk_buff **skb, struct uml_net_private *lp)
+static int mcast_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
- return mcast_user_write(fd, (*skb)->data, (*skb)->len,
+ return mcast_user_write(fd, skb->data, skb->len,
(struct mcast_data *) &lp->user);
}

Index: linux-2.6.20/arch/um/drivers/pcap_kern.c
===================================================================
--- linux-2.6.20.orig/arch/um/drivers/pcap_kern.c 2007-09-26 17:15:26.000000000 -0400
+++ linux-2.6.20/arch/um/drivers/pcap_kern.c 2007-09-26 17:19:31.000000000 -0400
@@ -31,19 +31,14 @@ void pcap_init(struct net_device *dev, v
printk("pcap backend, host interface %s\n", ppri->host_if);
}

-static int pcap_read(int fd, struct sk_buff **skb,
- struct uml_net_private *lp)
+static int pcap_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
- *skb = ether_adjust_skb(*skb, ETH_HEADER_OTHER);
- if (*skb == NULL)
- return -ENOMEM;
-
- return pcap_user_read(fd, skb_mac_header(*skb),
- (*skb)->dev->mtu + ETH_HEADER_OTHER,
+ return pcap_user_read(fd, skb_mac_header(skb),
+ skb->dev->mtu + ETH_HEADER_OTHER,
(struct pcap_data *) &lp->user);
}

-static int pcap_write(int fd, struct sk_buff **skb, struct uml_net_private *lp)
+static int pcap_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
return -EPERM;
}
Index: linux-2.6.20/arch/um/drivers/slip_kern.c
===================================================================
--- linux-2.6.20.orig/arch/um/drivers/slip_kern.c 2007-09-26 17:15:39.000000000 -0400
+++ linux-2.6.20/arch/um/drivers/slip_kern.c 2007-09-26 17:19:31.000000000 -0400
@@ -47,17 +47,15 @@ static unsigned short slip_protocol(stru
return htons(ETH_P_IP);
}

-static int slip_read(int fd, struct sk_buff **skb,
- struct uml_net_private *lp)
+static int slip_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
- return slip_user_read(fd, skb_mac_header(*skb), (*skb)->dev->mtu,
+ return slip_user_read(fd, skb_mac_header(skb), skb->dev->mtu,
(struct slip_data *) &lp->user);
}

-static int slip_write(int fd, struct sk_buff **skb,
- struct uml_net_private *lp)
+static int slip_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
- return slip_user_write(fd, (*skb)->data, (*skb)->len,
+ return slip_user_write(fd, skb->data, skb->len,
(struct slip_data *) &lp->user);
}

Index: linux-2.6.20/arch/um/drivers/slirp_kern.c
===================================================================
--- linux-2.6.20.orig/arch/um/drivers/slirp_kern.c 2007-09-26 17:15:55.000000000 -0400
+++ linux-2.6.20/arch/um/drivers/slirp_kern.c 2007-09-26 17:19:31.000000000 -0400
@@ -52,18 +52,16 @@ static unsigned short slirp_protocol(str
return htons(ETH_P_IP);
}

-static int slirp_read(int fd, struct sk_buff **skb,
- struct uml_net_private *lp)
+static int slirp_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
- return slirp_user_read(fd, skb_mac_header(*skb), (*skb)->dev->mtu,
- (struct slirp_data *) &lp->user);
+ return slirp_user_read(fd, skb_mac_header(skb), skb->dev->mtu,
+ (struct slirp_data *) &lp->user);
}

-static int slirp_write(int fd, struct sk_buff **skb,
- struct uml_net_private *lp)
+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);
+ return slirp_user_write(fd, skb->data, skb->len,
+ (struct slirp_data *) &lp->user);
}

const struct net_kern_info slirp_kern_info = {
Index: linux-2.6.20/arch/um/drivers/vde_kern.c
===================================================================
--- linux-2.6.20.orig/arch/um/drivers/vde_kern.c 2007-09-26 17:16:26.000000000 -0400
+++ linux-2.6.20/arch/um/drivers/vde_kern.c 2007-09-26 17:19:31.000000000 -0400
@@ -36,30 +36,25 @@ static void vde_init(struct net_device *
printk("\n");
}

-static int vde_read(int fd, struct sk_buff **skb, struct uml_net_private *lp)
+static int vde_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
struct vde_data *pri = (struct vde_data *) &lp->user;

- if (pri->conn != NULL) {
- *skb = ether_adjust_skb(*skb, ETH_HEADER_OTHER);
- if (*skb == NULL)
- return -ENOMEM;
-
- return vde_user_read(pri->conn, skb_mac_header(*skb),
- (*skb)->dev->mtu + ETH_HEADER_OTHER);
- }
+ if (pri->conn != NULL)
+ return vde_user_read(pri->conn, skb_mac_header(skb),
+ skb->dev->mtu + ETH_HEADER_OTHER);

printk(KERN_ERR "vde_read - we have no VDECONN to read from");
return -EBADF;
}

-static int vde_write(int fd, struct sk_buff **skb, struct uml_net_private *lp)
+static int vde_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
struct vde_data *pri = (struct vde_data *) &lp->user;

if (pri->conn != NULL)
- return vde_user_write((void *)pri->conn, (*skb)->data,
- (*skb)->len);
+ return vde_user_write((void *)pri->conn, skb->data,
+ skb->len);

printk(KERN_ERR "vde_write - we have no VDECONN to write to");
return -EBADF;
Index: linux-2.6.20/arch/um/include/net_kern.h
===================================================================
--- linux-2.6.20.orig/arch/um/include/net_kern.h 2007-09-26 17:14:23.000000000 -0400
+++ linux-2.6.20/arch/um/include/net_kern.h 2007-09-26 17:19:31.000000000 -0400
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2002 Jeff Dike (jdike@xxxxxxxxxx)
+ * Copyright (C) 2002 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/

@@ -30,24 +30,24 @@ struct uml_net_private {
struct work_struct work;
int fd;
unsigned char mac[ETH_ALEN];
+ int max_packet;
unsigned short (*protocol)(struct sk_buff *);
int (*open)(void *);
void (*close)(int, void *);
void (*remove)(void *);
- int (*read)(int, struct sk_buff **skb, struct uml_net_private *);
- int (*write)(int, struct sk_buff **skb, struct uml_net_private *);
+ int (*read)(int, struct sk_buff *skb, struct uml_net_private *);
+ int (*write)(int, struct sk_buff *skb, struct uml_net_private *);

void (*add_address)(unsigned char *, unsigned char *, void *);
void (*delete_address)(unsigned char *, unsigned char *, void *);
- int (*set_mtu)(int mtu, void *);
char user[0];
};

struct net_kern_info {
void (*init)(struct net_device *, void *);
unsigned short (*protocol)(struct sk_buff *);
- int (*read)(int, struct sk_buff **skb, struct uml_net_private *);
- int (*write)(int, struct sk_buff **skb, struct uml_net_private *);
+ int (*read)(int, struct sk_buff *skb, struct uml_net_private *);
+ int (*write)(int, struct sk_buff *skb, struct uml_net_private *);
};

struct transport {
@@ -62,7 +62,6 @@ struct transport {

extern struct net_device *ether_init(int);
extern unsigned short ether_protocol(struct sk_buff *);
-extern struct sk_buff *ether_adjust_skb(struct sk_buff *skb, int extra);
extern int tap_setup_common(char *str, char *type, char **dev_name,
char **mac_out, char **gate_addr);
extern void register_transport(struct transport *new);
Index: linux-2.6.20/arch/um/os-Linux/drivers/ethertap_kern.c
===================================================================
--- linux-2.6.20.orig/arch/um/os-Linux/drivers/ethertap_kern.c 2007-09-26 17:16:48.000000000 -0400
+++ linux-2.6.20/arch/um/os-Linux/drivers/ethertap_kern.c 2007-09-26 17:19:31.000000000 -0400
@@ -36,35 +36,24 @@ static void etap_init(struct net_device
printk("\n");
}

-static int etap_read(int fd, struct sk_buff **skb, struct uml_net_private *lp)
+static int etap_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
int len;

- *skb = ether_adjust_skb(*skb, ETH_HEADER_ETHERTAP);
- if (*skb == NULL)
- return -ENOMEM;
- len = net_recvfrom(fd, skb_mac_header(*skb),
- (*skb)->dev->mtu + 2 * ETH_HEADER_ETHERTAP);
+ len = net_recvfrom(fd, skb_mac_header(skb),
+ skb->dev->mtu + 2 + ETH_HEADER_ETHERTAP);
if (len <= 0)
- return len;
- skb_pull(*skb, 2);
+ return(len);
+
+ skb_pull(skb, 2);
len -= 2;
return len;
}

-static int etap_write(int fd, struct sk_buff **skb, struct uml_net_private *lp)
+static int etap_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
- if (skb_headroom(*skb) < 2) {
- struct sk_buff *skb2;
-
- skb2 = skb_realloc_headroom(*skb, 2);
- dev_kfree_skb(*skb);
- if (skb2 == NULL)
- return -ENOMEM;
- *skb = skb2;
- }
- skb_push(*skb, 2);
- return net_send(fd, (*skb)->data, (*skb)->len);
+ skb_push(skb, 2);
+ return net_send(fd, skb->data, skb->len);
}

const struct net_kern_info ethertap_kern_info = {
@@ -99,6 +88,7 @@ static struct transport ethertap_transpo
.user = &ethertap_user_info,
.kern = &ethertap_kern_info,
.private_size = sizeof(struct ethertap_data),
+ .setup_size = sizeof(struct ethertap_init),
};

static int register_ethertap(void)
Index: linux-2.6.20/arch/um/os-Linux/drivers/tuntap_kern.c
===================================================================
--- linux-2.6.20.orig/arch/um/os-Linux/drivers/tuntap_kern.c 2007-09-26 17:17:02.000000000 -0400
+++ linux-2.6.20/arch/um/os-Linux/drivers/tuntap_kern.c 2007-09-26 17:19:31.000000000 -0400
@@ -35,20 +35,15 @@ static void tuntap_init(struct net_devic
printk("\n");
}

-static int tuntap_read(int fd, struct sk_buff **skb,
- struct uml_net_private *lp)
+static int tuntap_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
- *skb = ether_adjust_skb(*skb, ETH_HEADER_OTHER);
- if (*skb == NULL)
- return -ENOMEM;
- return net_read(fd, skb_mac_header(*skb),
- (*skb)->dev->mtu + ETH_HEADER_OTHER);
+ return net_read(fd, skb_mac_header(skb),
+ skb->dev->mtu + ETH_HEADER_OTHER);
}

-static int tuntap_write(int fd, struct sk_buff **skb,
- struct uml_net_private *lp)
+static int tuntap_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
- return net_write(fd, (*skb)->data, (*skb)->len);
+ return net_write(fd, skb->data, skb->len);
}

const struct net_kern_info tuntap_kern_info = {
-
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