drivers/net/ppp/pppox.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /** -*- linux-c -*- ***********************************************************
   3  * Linux PPP over X/Ethernet (PPPoX/PPPoE) Sockets
   4  *
   5  * PPPoX --- Generic PPP encapsulation socket family
   6  * PPPoE --- PPP over Ethernet (RFC 2516)
   7  *
   8  * Version:     0.5.2
   9  *
  10  * Author:      Michal Ostrowski <mostrows@speakeasy.net>
  11  *
  12  * 051000 :     Initialization cleanup
  13  *
  14  * License:
  15  */
  16
  17 #include <linux/string.h>
  18 #include <linux/module.h>
  19 #include <linux/kernel.h>
  20 #include <linux/compat.h>
  21 #include <linux/errno.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/net.h>
  24 #include <linux/init.h>
  25 #include <linux/if_pppox.h>
  26 #include <linux/ppp_defs.h>
  27 #include <linux/ppp-ioctl.h>
  28 #include <linux/ppp_channel.h>
  29 #include <linux/kmod.h>
  30
  31 #include <net/sock.h>
  32
  33 #include <linux/uaccess.h>
  34
  35 static const struct pppox_proto *pppox_protos[PX_MAX_PROTO + 1];
  36
  37 int register_pppox_proto(int proto_num, const struct pppox_proto *pp)
  38 {
  39         if (proto_num < 0 || proto_num > PX_MAX_PROTO)
  40                 return -EINVAL;
  41         if (pppox_protos[proto_num])
  42                 return -EALREADY;
  43         pppox_protos[proto_num] = pp;
  44         return 0;
  45 }
  46
  47 void unregister_pppox_proto(int proto_num)
  48 {
  49         if (proto_num >= 0 && proto_num <= PX_MAX_PROTO)
  50                 pppox_protos[proto_num] = NULL;
  51 }
  52
  53 void pppox_unbind_sock(struct sock *sk)
  54 {
  55         /* Clear connection to ppp device, if attached. */
  56
  57         if (sk->sk_state & (PPPOX_BOUND | PPPOX_CONNECTED)) {
  58                 ppp_unregister_channel(&pppox_sk(sk)->chan);
  59                 sk->sk_state = PPPOX_DEAD;
  60         }
  61 }
  62
  63 EXPORT_SYMBOL(register_pppox_proto);
  64 EXPORT_SYMBOL(unregister_pppox_proto);
  65 EXPORT_SYMBOL(pppox_unbind_sock);
  66
  67 int pppox_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
  68 {
  69         struct sock *sk = sock->sk;
  70         struct pppox_sock *po = pppox_sk(sk);
  71         int rc;
  72
  73         lock_sock(sk);
  74
  75         switch (cmd) {
  76         case PPPIOCGCHAN: {
  77                 int index;
  78                 rc = -ENOTCONN;
  79                 if (!(sk->sk_state & PPPOX_CONNECTED))
  80                         break;
  81
  82                 rc = -EINVAL;
  83                 index = ppp_channel_index(&po->chan);
  84                 if (put_user(index , (int __user *) arg))
  85                         break;
  86
  87                 rc = 0;
  88                 sk->sk_state |= PPPOX_BOUND;
  89                 break;
  90         }
  91         default:
  92                 rc = pppox_protos[sk->sk_protocol]->ioctl ?
  93                         pppox_protos[sk->sk_protocol]->ioctl(sock, cmd, arg) : -ENOTTY;
  94         }
  95
  96         release_sock(sk);
  97         return rc;
  98 }
  99
 100 EXPORT_SYMBOL(pppox_ioctl);
 101
 102 #ifdef CONFIG_COMPAT
 103 int pppox_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 104 {
 105         if (cmd == PPPOEIOCSFWD32)
 106                 cmd = PPPOEIOCSFWD;
 107
 108         return pppox_ioctl(sock, cmd, (unsigned long)compat_ptr(arg));
 109 }
 110
 111 EXPORT_SYMBOL(pppox_compat_ioctl);
 112 #endif
 113
 114 static int pppox_create(struct net *net, struct socket *sock, int protocol,
 115                         int kern)
 116 {
 117         int rc = -EPROTOTYPE;
 118
 119         if (protocol < 0 || protocol > PX_MAX_PROTO)
 120                 goto out;
 121
 122         rc = -EPROTONOSUPPORT;
 123         if (!pppox_protos[protocol])
 124                 request_module("net-pf-%d-proto-%d", PF_PPPOX, protocol);
 125         if (!pppox_protos[protocol] ||
 126             !try_module_get(pppox_protos[protocol]->owner))
 127                 goto out;
 128
 129         rc = pppox_protos[protocol]->create(net, sock, kern);
 130
 131         module_put(pppox_protos[protocol]->owner);
 132 out:
 133         return rc;
 134 }
 135
 136 static const struct net_proto_family pppox_proto_family = {
 137         .family = PF_PPPOX,
 138         .create = pppox_create,
 139         .owner  = THIS_MODULE,
 140 };
 141
 142 static int __init pppox_init(void)
 143 {
 144         return sock_register(&pppox_proto_family);
 145 }
 146
 147 static void __exit pppox_exit(void)
 148 {
 149         sock_unregister(PF_PPPOX);
 150 }
 151
 152 module_init(pppox_init);
 153 module_exit(pppox_exit);
 154
 155 MODULE_AUTHOR("Michal Ostrowski <mostrows@speakeasy.net>");
 156 MODULE_DESCRIPTION("PPP over Ethernet driver (generic socket layer)");
 157 MODULE_LICENSE("GPL");
 158 MODULE_ALIAS_NETPROTO(PF_PPPOX);