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uml: network driver MTU cleanups

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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@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jeff Dike
2007-10-16 01:27:31 -07:00
committed by Linus Torvalds
parent cd1ae0e49b
commit b53f35a809
19 changed files with 80 additions and 188 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
arch/um/os-Linux/drivers/ethertap_kern.c
View File

@@ -36,35 +36,24 @@ static void etap_init(struct net_device *dev, void *data)
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_transport = {
.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)

9
arch/um/os-Linux/drivers/ethertap_user.c
View File

@@ -222,11 +222,6 @@ static void etap_close(int fd, void *data)
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_info = {
.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,
};

15
arch/um/os-Linux/drivers/tuntap_kern.c
View File

@@ -35,20 +35,15 @@ static void tuntap_init(struct net_device *dev, void *data)
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 = {

11
arch/um/os-Linux/drivers/tuntap_user.c
View File

@@ -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 *data)
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,
};