drivers/net/wan/hdlc_ppp.c

   1 /*
   2  * Generic HDLC support routines for Linux
   3  * Point-to-point protocol support
   4  *
   5  * Copyright (C) 1999 - 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/hdlc.h>
  25 #include <net/syncppp.h>
  26
  27 struct ppp_state {
  28         struct ppp_device pppdev;
  29         struct ppp_device *syncppp_ptr;
  30         int (*old_change_mtu)(struct net_device *dev, int new_mtu);
  31 };
  32
  33 static int ppp_ioctl(struct net_device *dev, struct ifreq *ifr);
  34
  35
  36 static inline struct ppp_state* state(hdlc_device *hdlc)
  37 {
  38         return(struct ppp_state *)(hdlc->state);
  39 }
  40
  41
  42 static int ppp_open(struct net_device *dev)
  43 {
  44         hdlc_device *hdlc = dev_to_hdlc(dev);
  45         int (*old_ioctl)(struct net_device *, struct ifreq *, int);
  46         int result;
  47
  48         dev->priv = &state(hdlc)->syncppp_ptr;
  49         state(hdlc)->syncppp_ptr = &state(hdlc)->pppdev;
  50         state(hdlc)->pppdev.dev = dev;
  51
  52         old_ioctl = dev->do_ioctl;
  53         state(hdlc)->old_change_mtu = dev->change_mtu;
  54         sppp_attach(&state(hdlc)->pppdev);
  55         /* sppp_attach nukes them. We don't need syncppp's ioctl */
  56         dev->do_ioctl = old_ioctl;
  57         state(hdlc)->pppdev.sppp.pp_flags &= ~PP_CISCO;
  58         dev->type = ARPHRD_PPP;
  59         result = sppp_open(dev);
  60         if (result) {
  61                 sppp_detach(dev);
  62                 return result;
  63         }
  64
  65         return 0;
  66 }
  67
  68
  69
  70 static void ppp_close(struct net_device *dev)
  71 {
  72         hdlc_device *hdlc = dev_to_hdlc(dev);
  73
  74         sppp_close(dev);
  75         sppp_detach(dev);
  76
  77         dev->change_mtu = state(hdlc)->old_change_mtu;
  78         dev->mtu = HDLC_MAX_MTU;
  79         dev->hard_header_len = 16;
  80 }
  81
  82
  83
  84 static __be16 ppp_type_trans(struct sk_buff *skb, struct net_device *dev)
  85 {
  86         return __constant_htons(ETH_P_WAN_PPP);
  87 }
  88
  89
  90
  91 static struct hdlc_proto proto = {
  92         .open           = ppp_open,
  93         .close          = ppp_close,
  94         .type_trans     = ppp_type_trans,
  95         .ioctl          = ppp_ioctl,
  96         .module         = THIS_MODULE,
  97 };
  98
  99
 100 static int ppp_ioctl(struct net_device *dev, struct ifreq *ifr)
 101 {
 102         hdlc_device *hdlc = dev_to_hdlc(dev);
 103         int result;
 104
 105         switch (ifr->ifr_settings.type) {
 106         case IF_GET_PROTO:
 107                 if (dev_to_hdlc(dev)->proto != &proto)
 108                         return -EINVAL;
 109                 ifr->ifr_settings.type = IF_PROTO_PPP;
 110                 return 0; /* return protocol only, no settable parameters */
 111
 112         case IF_PROTO_PPP:
 113                 if(!capable(CAP_NET_ADMIN))
 114                         return -EPERM;
 115
 116                 if(dev->flags & IFF_UP)
 117                         return -EBUSY;
 118
 119                 /* no settable parameters */
 120
 121                 result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 122                 if (result)
 123                         return result;
 124
 125                 result = attach_hdlc_protocol(dev, &proto, NULL,
 126                                               sizeof(struct ppp_state));
 127                 if (result)
 128                         return result;
 129                 dev->hard_start_xmit = hdlc->xmit;
 130                 dev->type = ARPHRD_PPP;
 131                 netif_dormant_off(dev);
 132                 return 0;
 133         }
 134
 135         return -EINVAL;
 136 }
 137
 138
 139 static int __init mod_init(void)
 140 {
 141         register_hdlc_protocol(&proto);
 142         return 0;
 143 }
 144
 145
 146
 147 static void __exit mod_exit(void)
 148 {
 149         unregister_hdlc_protocol(&proto);
 150 }
 151
 152
 153 module_init(mod_init);
 154 module_exit(mod_exit);
 155
 156 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 157 MODULE_DESCRIPTION("PPP protocol support for generic HDLC");
 158 MODULE_LICENSE("GPL v2");