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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 <[email protected]>
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 struct sk_buff *skb;
78 int index;
79
80 rc = -ENOTCONN;
81 if (!(sk->sk_state & PPPOX_CONNECTED))
82 break;
83
84 rc = -EINVAL;
85 index = ppp_channel_index(&po->chan);
86 if (put_user(index , (int __user *) arg))
87 break;
88
89 rc = 0;
90 /* PPPIOCGCHAN historically marks the userspace handoff to
91 * generic PPP; pppd then attaches the returned channel to
92 * /dev/ppp.
93 */
94 sk->sk_state |= PPPOX_BOUND;
95 /* Let lockless receive paths finish queueing against the old
96 * state.
97 */
98 synchronize_net();
99 /* Drain packets queued before the handoff because a bound
100 * socket is no longer readable.
101 */
102 while ((skb = skb_dequeue(&sk->sk_receive_queue))) {
103 skb_orphan(skb);
104 ppp_input(&po->chan, skb);
105 }
106 break;
107 }
108 default:
109 rc = pppox_protos[sk->sk_protocol]->ioctl ?
110 pppox_protos[sk->sk_protocol]->ioctl(sock, cmd, arg) : -ENOTTY;
111 }
112
113 release_sock(sk);
114 return rc;
115}
116
117EXPORT_SYMBOL(pppox_ioctl);
118
119#ifdef CONFIG_COMPAT
120int pppox_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
121{
122 return pppox_ioctl(sock, cmd, (unsigned long)compat_ptr(arg));
123}
124
125EXPORT_SYMBOL(pppox_compat_ioctl);
126#endif
127
128static int pppox_create(struct net *net, struct socket *sock, int protocol,
129 int kern)
130{
131 int rc = -EPROTOTYPE;
132
133 if (protocol < 0 || protocol > PX_MAX_PROTO)
134 goto out;
135
136 rc = -EPROTONOSUPPORT;
137 if (!pppox_protos[protocol])
138 request_module("net-pf-%d-proto-%d", PF_PPPOX, protocol);
139 if (!pppox_protos[protocol] ||
140 !try_module_get(pppox_protos[protocol]->owner))
141 goto out;
142
143 rc = pppox_protos[protocol]->create(net, sock, kern);
144
145 module_put(pppox_protos[protocol]->owner);
146out:
147 return rc;
148}
149
150static const struct net_proto_family pppox_proto_family = {
151 .family = PF_PPPOX,
152 .create = pppox_create,
153 .owner = THIS_MODULE,
154};
155
156static int __init pppox_init(void)
157{
158 return sock_register(&pppox_proto_family);
159}
160
161static void __exit pppox_exit(void)
162{
163 sock_unregister(PF_PPPOX);
164}
165
166module_init(pppox_init);
167module_exit(pppox_exit);
168
169MODULE_AUTHOR("Michal Ostrowski <[email protected]>");
170MODULE_DESCRIPTION("PPP over Ethernet driver (generic socket layer)");
171MODULE_LICENSE("GPL");
172MODULE_ALIAS_NETPROTO(PF_PPPOX);