drivers/net/wan/hdlc_raw_eth.c

   1 /*
   2  * Generic HDLC support routines for Linux
   3  * HDLC Ethernet emulation support
   4  *
   5  * Copyright (C) 2002-2006 Krzysztof Halasa <khc@pm.waw.pl>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of version 2 of the GNU General Public License
   9  * as published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/kernel.h>
  14 #include <linux/slab.h>
  15 #include <linux/poll.h>
  16 #include <linux/errno.h>
  17 #include <linux/if_arp.h>
  18 #include <linux/init.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/pkt_sched.h>
  21 #include <linux/random.h>
  22 #include <linux/inetdevice.h>
  23 #include <linux/lapb.h>
  24 #include <linux/rtnetlink.h>
  25 #include <linux/etherdevice.h>
  26 #include <linux/hdlc.h>
  27
  28 static int raw_eth_ioctl(struct net_device *dev, struct ifreq *ifr);
  29
  30 static int eth_tx(struct sk_buff *skb, struct net_device *dev)
  31 {
  32         int pad = ETH_ZLEN - skb->len;
  33         if (pad > 0) {          /* Pad the frame with zeros */
  34                 int len = skb->len;
  35                 if (skb_tailroom(skb) < pad)
  36                         if (pskb_expand_head(skb, 0, pad, GFP_ATOMIC)) {
  37                                 hdlc_stats(dev)->tx_dropped++;
  38                                 dev_kfree_skb(skb);
  39                                 return 0;
  40                         }
  41                 skb_put(skb, pad);
  42                 memset(skb->data + len, 0, pad);
  43         }
  44         return dev_to_hdlc(dev)->xmit(skb, dev);
  45 }
  46
  47
  48 static struct hdlc_proto proto = {
  49         .type_trans     = eth_type_trans,
  50         .ioctl          = raw_eth_ioctl,
  51         .module         = THIS_MODULE,
  52 };
  53
  54
  55 static int raw_eth_ioctl(struct net_device *dev, struct ifreq *ifr)
  56 {
  57         raw_hdlc_proto __user *raw_s = ifr->ifr_settings.ifs_ifsu.raw_hdlc;
  58         const size_t size = sizeof(raw_hdlc_proto);
  59         raw_hdlc_proto new_settings;
  60         hdlc_device *hdlc = dev_to_hdlc(dev);
  61         int result;
  62         int (*old_ch_mtu)(struct net_device *, int);
  63         int old_qlen;
  64
  65         switch (ifr->ifr_settings.type) {
  66         case IF_GET_PROTO:
  67                 if (dev_to_hdlc(dev)->proto != &proto)
  68                         return -EINVAL;
  69                 ifr->ifr_settings.type = IF_PROTO_HDLC_ETH;
  70                 if (ifr->ifr_settings.size < size) {
  71                         ifr->ifr_settings.size = size; /* data size wanted */
  72                         return -ENOBUFS;
  73                 }
  74                 if (copy_to_user(raw_s, hdlc->state, size))
  75                         return -EFAULT;
  76                 return 0;
  77
  78         case IF_PROTO_HDLC_ETH:
  79                 if (!capable(CAP_NET_ADMIN))
  80                         return -EPERM;
  81
  82                 if (dev->flags & IFF_UP)
  83                         return -EBUSY;
  84
  85                 if (copy_from_user(&new_settings, raw_s, size))
  86                         return -EFAULT;
  87
  88                 if (new_settings.encoding == ENCODING_DEFAULT)
  89                         new_settings.encoding = ENCODING_NRZ;
  90
  91                 if (new_settings.parity == PARITY_DEFAULT)
  92                         new_settings.parity = PARITY_CRC16_PR1_CCITT;
  93
  94                 result = hdlc->attach(dev, new_settings.encoding,
  95                                       new_settings.parity);
  96                 if (result)
  97                         return result;
  98
  99                 result = attach_hdlc_protocol(dev, &proto, NULL,
 100                                               sizeof(raw_hdlc_proto));
 101                 if (result)
 102                         return result;
 103                 memcpy(hdlc->state, &new_settings, size);
 104                 dev->hard_start_xmit = eth_tx;
 105                 old_ch_mtu = dev->change_mtu;
 106                 old_qlen = dev->tx_queue_len;
 107                 ether_setup(dev);
 108                 dev->change_mtu = old_ch_mtu;
 109                 dev->tx_queue_len = old_qlen;
 110                 memcpy(dev->dev_addr, "\x00\x01", 2);
 111                 get_random_bytes(dev->dev_addr + 2, ETH_ALEN - 2);
 112                 netif_dormant_off(dev);
 113                 return 0;
 114         }
 115
 116         return -EINVAL;
 117 }
 118
 119
 120 static int __init mod_init(void)
 121 {
 122         register_hdlc_protocol(&proto);
 123         return 0;
 124 }
 125
 126
 127
 128 static void __exit mod_exit(void)
 129 {
 130         unregister_hdlc_protocol(&proto);
 131 }
 132
 133
 134 module_init(mod_init);
 135 module_exit(mod_exit);
 136
 137 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 138 MODULE_DESCRIPTION("Ethernet encapsulation support for generic HDLC");
 139 MODULE_LICENSE("GPL v2");