arch/um/os-Linux/drivers/ethertap_kern.c

   1 /*
   2  * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and
   3  * James Leu (jleu@mindspring.net).
   4  * Copyright (C) 2001 by various other people who didn't put their name here.
   5  * Licensed under the GPL.
   6  */
   7
   8 #include "linux/init.h"
   9 #include "linux/netdevice.h"
  10 #include "linux/etherdevice.h"
  11 #include "net_kern.h"
  12 #include "net_user.h"
  13 #include "etap.h"
  14
  15 struct ethertap_init {
  16         char *dev_name;
  17         char *gate_addr;
  18 };
  19
  20 static void etap_init(struct net_device *dev, void *data)
  21 {
  22         struct uml_net_private *pri;
  23         struct ethertap_data *epri;
  24         struct ethertap_init *init = data;
  25
  26         pri = dev->priv;
  27         epri = (struct ethertap_data *) pri->user;
  28         epri->dev_name = init->dev_name;
  29         epri->gate_addr = init->gate_addr;
  30         epri->data_fd = -1;
  31         epri->control_fd = -1;
  32         epri->dev = dev;
  33
  34         printk("ethertap backend - %s", epri->dev_name);
  35         if (epri->gate_addr != NULL)
  36                 printk(", IP = %s", epri->gate_addr);
  37         printk("\n");
  38 }
  39
  40 static int etap_read(int fd, struct sk_buff **skb, struct uml_net_private *lp)
  41 {
  42         int len;
  43
  44         *skb = ether_adjust_skb(*skb, ETH_HEADER_ETHERTAP);
  45         if(*skb == NULL) return(-ENOMEM);
  46         len = net_recvfrom(fd, (*skb)->mac.raw,
  47                            (*skb)->dev->mtu + 2 * ETH_HEADER_ETHERTAP);
  48         if(len <= 0) return(len);
  49         skb_pull(*skb, 2);
  50         len -= 2;
  51         return(len);
  52 }
  53
  54 static int etap_write(int fd, struct sk_buff **skb, struct uml_net_private *lp)
  55 {
  56         if(skb_headroom(*skb) < 2){
  57                 struct sk_buff *skb2;
  58
  59                 skb2 = skb_realloc_headroom(*skb, 2);
  60                 dev_kfree_skb(*skb);
  61                 if (skb2 == NULL) return(-ENOMEM);
  62                 *skb = skb2;
  63         }
  64         skb_push(*skb, 2);
  65         return(net_send(fd, (*skb)->data, (*skb)->len));
  66 }
  67
  68 const struct net_kern_info ethertap_kern_info = {
  69         .init                   = etap_init,
  70         .protocol               = eth_protocol,
  71         .read                   = etap_read,
  72         .write                  = etap_write,
  73 };
  74
  75 int ethertap_setup(char *str, char **mac_out, void *data)
  76 {
  77         struct ethertap_init *init = data;
  78
  79         *init = ((struct ethertap_init)
  80                 { .dev_name     = NULL,
  81                   .gate_addr    = NULL });
  82         if(tap_setup_common(str, "ethertap", &init->dev_name, mac_out,
  83                             &init->gate_addr))
  84                 return(0);
  85         if(init->dev_name == NULL){
  86                 printk("ethertap_setup : Missing tap device name\n");
  87                 return(0);
  88         }
  89
  90         return(1);
  91 }
  92
  93 static struct transport ethertap_transport = {
  94         .list           = LIST_HEAD_INIT(ethertap_transport.list),
  95         .name           = "ethertap",
  96         .setup          = ethertap_setup,
  97         .user           = &ethertap_user_info,
  98         .kern           = &ethertap_kern_info,
  99         .private_size   = sizeof(struct ethertap_data),
 100 };
 101
 102 static int register_ethertap(void)
 103 {
 104         register_transport(&ethertap_transport);
 105         return 0;
 106 }
 107
 108 late_initcall(register_ethertap);