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