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