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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and
   4  * James Leu (jleu@mindspring.net).
   5  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   6  * Copyright (C) 2001 by various other people who didn't put their name here.
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/netdevice.h>
  11 #include "etap.h"
  12 #include <net_kern.h>
  13
  14 struct ethertap_init {
  15         char *dev_name;
  16         char *gate_addr;
  17 };
  18
  19 static void etap_init(struct net_device *dev, void *data)
  20 {
  21         struct uml_net_private *pri;
  22         struct ethertap_data *epri;
  23         struct ethertap_init *init = data;
  24
  25         pri = netdev_priv(dev);
  26         epri = (struct ethertap_data *) pri->user;
  27         epri->dev_name = init->dev_name;
  28         epri->gate_addr = init->gate_addr;
  29         epri->data_fd = -1;
  30         epri->control_fd = -1;
  31         epri->dev = dev;
  32
  33         printk(KERN_INFO "ethertap backend - %s", epri->dev_name);
  34         if (epri->gate_addr != NULL)
  35                 printk(KERN_CONT ", IP = %s", epri->gate_addr);
  36         printk(KERN_CONT "\n");
  37 }
  38
  39 static int etap_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
  40 {
  41         int len;
  42
  43         len = net_recvfrom(fd, skb_mac_header(skb),
  44                            skb->dev->mtu + 2 + ETH_HEADER_ETHERTAP);
  45         if (len <= 0)
  46                 return(len);
  47
  48         skb_pull(skb, 2);
  49         len -= 2;
  50         return len;
  51 }
  52
  53 static int etap_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
  54 {
  55         skb_push(skb, 2);
  56         return net_send(fd, skb->data, skb->len);
  57 }
  58
  59 const struct net_kern_info ethertap_kern_info = {
  60         .init                   = etap_init,
  61         .protocol               = eth_protocol,
  62         .read                   = etap_read,
  63         .write                  = etap_write,
  64 };
  65
  66 int ethertap_setup(char *str, char **mac_out, void *data)
  67 {
  68         struct ethertap_init *init = data;
  69
  70         *init = ((struct ethertap_init)
  71                 { .dev_name     = NULL,
  72                   .gate_addr    = NULL });
  73         if (tap_setup_common(str, "ethertap", &init->dev_name, mac_out,
  74                             &init->gate_addr))
  75                 return 0;
  76         if (init->dev_name == NULL) {
  77                 printk(KERN_ERR "ethertap_setup : Missing tap device name\n");
  78                 return 0;
  79         }
  80
  81         return 1;
  82 }
  83
  84 static struct transport ethertap_transport = {
  85         .list           = LIST_HEAD_INIT(ethertap_transport.list),
  86         .name           = "ethertap",
  87         .setup          = ethertap_setup,
  88         .user           = &ethertap_user_info,
  89         .kern           = &ethertap_kern_info,
  90         .private_size   = sizeof(struct ethertap_data),
  91         .setup_size     = sizeof(struct ethertap_init),
  92 };
  93
  94 static int register_ethertap(void)
  95 {
  96         register_transport(&ethertap_transport);
  97         return 0;
  98 }
  99
 100 late_initcall(register_ethertap);