b53f35a809
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>
101 lines
2.3 KiB
C
101 lines
2.3 KiB
C
/*
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* Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and
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* James Leu (jleu@mindspring.net).
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* Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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* Copyright (C) 2001 by various other people who didn't put their name here.
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* Licensed under the GPL.
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*/
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#include "linux/init.h"
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#include <linux/netdevice.h>
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#include "etap.h"
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#include "net_kern.h"
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struct ethertap_init {
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char *dev_name;
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char *gate_addr;
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};
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static void etap_init(struct net_device *dev, void *data)
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{
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struct uml_net_private *pri;
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struct ethertap_data *epri;
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struct ethertap_init *init = data;
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pri = dev->priv;
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epri = (struct ethertap_data *) pri->user;
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epri->dev_name = init->dev_name;
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epri->gate_addr = init->gate_addr;
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epri->data_fd = -1;
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epri->control_fd = -1;
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epri->dev = dev;
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printk("ethertap backend - %s", epri->dev_name);
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if (epri->gate_addr != NULL)
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printk(", IP = %s", epri->gate_addr);
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printk("\n");
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}
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static int etap_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
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{
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int len;
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len = net_recvfrom(fd, skb_mac_header(skb),
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skb->dev->mtu + 2 + ETH_HEADER_ETHERTAP);
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if (len <= 0)
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return(len);
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skb_pull(skb, 2);
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len -= 2;
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return len;
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}
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static int etap_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
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{
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skb_push(skb, 2);
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return net_send(fd, skb->data, skb->len);
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}
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const struct net_kern_info ethertap_kern_info = {
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.init = etap_init,
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.protocol = eth_protocol,
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.read = etap_read,
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.write = etap_write,
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};
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int ethertap_setup(char *str, char **mac_out, void *data)
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{
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struct ethertap_init *init = data;
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*init = ((struct ethertap_init)
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{ .dev_name = NULL,
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.gate_addr = NULL });
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if (tap_setup_common(str, "ethertap", &init->dev_name, mac_out,
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&init->gate_addr))
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return 0;
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if (init->dev_name == NULL) {
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printk(KERN_ERR "ethertap_setup : Missing tap device name\n");
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return 0;
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}
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return 1;
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}
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static struct transport ethertap_transport = {
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.list = LIST_HEAD_INIT(ethertap_transport.list),
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.name = "ethertap",
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.setup = ethertap_setup,
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.user = ðertap_user_info,
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.kern = ðertap_kern_info,
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.private_size = sizeof(struct ethertap_data),
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.setup_size = sizeof(struct ethertap_init),
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};
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static int register_ethertap(void)
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{
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register_transport(ðertap_transport);
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return 0;
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}
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late_initcall(register_ethertap);
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