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
 35static const struct pppox_proto *pppox_protos[PX_MAX_PROTO + 1];
 36
 37int 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
 47void 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
 53void 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
 63EXPORT_SYMBOL(register_pppox_proto);
 64EXPORT_SYMBOL(unregister_pppox_proto);
 65EXPORT_SYMBOL(pppox_unbind_sock);
 66
 67int 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
100EXPORT_SYMBOL(pppox_ioctl);
101
102#ifdef CONFIG_COMPAT
103int 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
111EXPORT_SYMBOL(pppox_compat_ioctl);
112#endif
113
114static 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);
132out:
133	return rc;
134}
135
136static const struct net_proto_family pppox_proto_family = {
137	.family	= PF_PPPOX,
138	.create	= pppox_create,
139	.owner	= THIS_MODULE,
140};
141
142static int __init pppox_init(void)
143{
144	return sock_register(&pppox_proto_family);
145}
146
147static void __exit pppox_exit(void)
148{
149	sock_unregister(PF_PPPOX);
150}
151
152module_init(pppox_init);
153module_exit(pppox_exit);
154
155MODULE_AUTHOR("Michal Ostrowski <mostrows@speakeasy.net>");
156MODULE_DESCRIPTION("PPP over Ethernet driver (generic socket layer)");
157MODULE_LICENSE("GPL");
158MODULE_ALIAS_NETPROTO(PF_PPPOX);