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 "linux/init.h"
  12 #include "net_kern.h"
  13 #include "net_user.h"
  14 #include "etap.h"
  15
  16 struct ethertap_init {
  17         char *dev_name;
  18         char *gate_addr;
  19 };
  20
  21 static void etap_init(struct net_device *dev, void *data)
  22 {
  23         struct uml_net_private *pri;
  24         struct ethertap_data *epri;
  25         struct ethertap_init *init = data;
  26
  27         pri = dev->priv;
  28         epri = (struct ethertap_data *) pri->user;
  29         epri->dev_name = init->dev_name;
  30         epri->gate_addr = init->gate_addr;
  31         epri->data_fd = -1;
  32         epri->control_fd = -1;
  33         epri->dev = dev;
  34
  35         printk("ethertap backend - %s", epri->dev_name);
  36         if (epri->gate_addr != NULL)
  37                 printk(", IP = %s", epri->gate_addr);
  38         printk("\n");
  39 }
  40
  41 static int etap_read(int fd, struct sk_buff **skb, struct uml_net_private *lp)
  42 {
  43         int len;
  44
  45         *skb = ether_adjust_skb(*skb, ETH_HEADER_ETHERTAP);
  46         if(*skb == NULL) return(-ENOMEM);
  47         len = net_recvfrom(fd, (*skb)->mac.raw,
  48                            (*skb)->dev->mtu + 2 * ETH_HEADER_ETHERTAP);
  49         if(len <= 0) return(len);
  50         skb_pull(*skb, 2);
  51         len -= 2;
  52         return(len);
  53 }
  54
  55 static int etap_write(int fd, struct sk_buff **skb, struct uml_net_private *lp)
  56 {
  57         if(skb_headroom(*skb) < 2){
  58                 struct sk_buff *skb2;
  59
  60                 skb2 = skb_realloc_headroom(*skb, 2);
  61                 dev_kfree_skb(*skb);
  62                 if (skb2 == NULL) return(-ENOMEM);
  63                 *skb = skb2;
  64         }
  65         skb_push(*skb, 2);
  66         return(net_send(fd, (*skb)->data, (*skb)->len));
  67 }
  68
  69 struct net_kern_info ethertap_kern_info = {
  70         .init                   = etap_init,
  71         .protocol               = eth_protocol,
  72         .read                   = etap_read,
  73         .write                  = etap_write,
  74 };
  75
  76 int ethertap_setup(char *str, char **mac_out, void *data)
  77 {
  78         struct ethertap_init *init = data;
  79
  80         *init = ((struct ethertap_init)
  81                 { .dev_name     = NULL,
  82                   .gate_addr    = NULL });
  83         if(tap_setup_common(str, "ethertap", &init->dev_name, mac_out,
  84                             &init->gate_addr))
  85                 return(0);
  86         if(init->dev_name == NULL){
  87                 printk("ethertap_setup : Missing tap device name\n");
  88                 return(0);
  89         }
  90
  91         return(1);
  92 }
  93
  94 static struct transport ethertap_transport = {
  95         .list           = LIST_HEAD_INIT(ethertap_transport.list),
  96         .name           = "ethertap",
  97         .setup          = ethertap_setup,
  98         .user           = &ethertap_user_info,
  99         .kern           = &ethertap_kern_info,
 100         .private_size   = sizeof(struct ethertap_data),
 101 };
 102
 103 static int register_ethertap(void)
 104 {
 105         register_transport(&ethertap_transport);
 106         return(1);
 107 }
 108
 109 __initcall(register_ethertap);
 110
 111 /*
 112  * Overrides for Emacs so that we follow Linus's tabbing style.
 113  * Emacs will notice this stuff at the end of the file and automatically
 114  * adjust the settings for this buffer only.  This must remain at the end
 115  * of the file.
 116  * ---------------------------------------------------------------------------
 117  * Local variables:
 118  * c-file-style: "linux"
 119  * End:
 120  */