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