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 netdev_tx_t 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         .xmit           = eth_tx,
  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, old_qlen;
  61
  62         switch (ifr->ifr_settings.type) {
  63         case IF_GET_PROTO:
  64                 if (dev_to_hdlc(dev)->proto != &proto)
  65                         return -EINVAL;
  66                 ifr->ifr_settings.type = IF_PROTO_HDLC_ETH;
  67                 if (ifr->ifr_settings.size < size) {
  68                         ifr->ifr_settings.size = size; /* data size wanted */
  69                         return -ENOBUFS;
  70                 }
  71                 if (copy_to_user(raw_s, hdlc->state, size))
  72                         return -EFAULT;
  73                 return 0;
  74
  75         case IF_PROTO_HDLC_ETH:
  76                 if (!capable(CAP_NET_ADMIN))
  77                         return -EPERM;
  78
  79                 if (dev->flags & IFF_UP)
  80                         return -EBUSY;
  81
  82                 if (copy_from_user(&new_settings, raw_s, size))
  83                         return -EFAULT;
  84
  85                 if (new_settings.encoding == ENCODING_DEFAULT)
  86                         new_settings.encoding = ENCODING_NRZ;
  87
  88                 if (new_settings.parity == PARITY_DEFAULT)
  89                         new_settings.parity = PARITY_CRC16_PR1_CCITT;
  90
  91                 result = hdlc->attach(dev, new_settings.encoding,
  92                                       new_settings.parity);
  93                 if (result)
  94                         return result;
  95
  96                 result = attach_hdlc_protocol(dev, &proto,
  97                                               sizeof(raw_hdlc_proto));
  98                 if (result)
  99                         return result;
 100                 memcpy(hdlc->state, &new_settings, size);
 101                 old_qlen = dev->tx_queue_len;
 102                 ether_setup(dev);
 103                 dev->tx_queue_len = old_qlen;
 104                 random_ether_addr(dev->dev_addr);
 105                 netif_dormant_off(dev);
 106                 return 0;
 107         }
 108
 109         return -EINVAL;
 110 }
 111
 112
 113 static int __init mod_init(void)
 114 {
 115         register_hdlc_protocol(&proto);
 116         return 0;
 117 }
 118
 119
 120
 121 static void __exit mod_exit(void)
 122 {
 123         unregister_hdlc_protocol(&proto);
 124 }
 125
 126
 127 module_init(mod_init);
 128 module_exit(mod_exit);
 129
 130 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 131 MODULE_DESCRIPTION("Ethernet encapsulation support for generic HDLC");
 132 MODULE_LICENSE("GPL v2");