[deliverable/linux.git] / drivers / net / ppp / pptp.c

/*
 *  Point-to-Point Tunneling Protocol for Linux
 *
 *	Authors: Dmitry Kozlov <xeb@mail.ru>
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 *
 */

#include <linux/string.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/ppp_channel.h>
#include <linux/ppp_defs.h>
#include <linux/if_pppox.h>
#include <linux/ppp-ioctl.h>
#include <linux/notifier.h>
#include <linux/file.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/rcupdate.h>
#include <linux/spinlock.h>

#include <net/sock.h>
#include <net/protocol.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/route.h>
#include <net/gre.h>
#include <net/pptp.h>

#include <linux/uaccess.h>

#define PPTP_DRIVER_VERSION "0.8.5"

#define MAX_CALLID 65535

static DECLARE_BITMAP(callid_bitmap, MAX_CALLID + 1);
static struct pppox_sock __rcu **callid_sock;

static DEFINE_SPINLOCK(chan_lock);

static struct proto pptp_sk_proto __read_mostly;
static const struct ppp_channel_ops pptp_chan_ops;
static const struct proto_ops pptp_ops;

static struct pppox_sock *lookup_chan(u16 call_id, __be32 s_addr)
{
	struct pppox_sock *sock;
	struct pptp_opt *opt;

	rcu_read_lock();
	sock = rcu_dereference(callid_sock[call_id]);
	if (sock) {
		opt = &sock->proto.pptp;
		if (opt->dst_addr.sin_addr.s_addr != s_addr)
			sock = NULL;
		else
			sock_hold(sk_pppox(sock));
	}
	rcu_read_unlock();

	return sock;
}

static int lookup_chan_dst(u16 call_id, __be32 d_addr)
{
	struct pppox_sock *sock;
	struct pptp_opt *opt;
	int i;

	rcu_read_lock();
	i = 1;
	for_each_set_bit_from(i, callid_bitmap, MAX_CALLID) {
		sock = rcu_dereference(callid_sock[i]);
		if (!sock)
			continue;
		opt = &sock->proto.pptp;
		if (opt->dst_addr.call_id == call_id &&
			  opt->dst_addr.sin_addr.s_addr == d_addr)
			break;
	}
	rcu_read_unlock();

	return i < MAX_CALLID;
}

static int add_chan(struct pppox_sock *sock,
		    struct pptp_addr *sa)
{
	static int call_id;

	spin_lock(&chan_lock);
	if (!sa->call_id)	{
		call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, call_id + 1);
		if (call_id == MAX_CALLID) {
			call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, 1);
			if (call_id == MAX_CALLID)
				goto out_err;
		}
		sa->call_id = call_id;
	} else if (test_bit(sa->call_id, callid_bitmap)) {
		goto out_err;
	}

	sock->proto.pptp.src_addr = *sa;
	set_bit(sa->call_id, callid_bitmap);
	rcu_assign_pointer(callid_sock[sa->call_id], sock);
	spin_unlock(&chan_lock);

	return 0;

out_err:
	spin_unlock(&chan_lock);
	return -1;
}

static void del_chan(struct pppox_sock *sock)
{
	spin_lock(&chan_lock);
	clear_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap);
	RCU_INIT_POINTER(callid_sock[sock->proto.pptp.src_addr.call_id], NULL);
	spin_unlock(&chan_lock);
	synchronize_rcu();
}

static int pptp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
{
	struct sock *sk = (struct sock *) chan->private;
	struct pppox_sock *po = pppox_sk(sk);
	struct net *net = sock_net(sk);
	struct pptp_opt *opt = &po->proto.pptp;
	struct pptp_gre_header *hdr;
	unsigned int header_len = sizeof(*hdr);
	struct flowi4 fl4;
	int islcp;
	int len;
	unsigned char *data;
	__u32 seq_recv;


	struct rtable *rt;
	struct net_device *tdev;
	struct iphdr  *iph;
	int    max_headroom;

	if (sk_pppox(po)->sk_state & PPPOX_DEAD)
		goto tx_error;

	rt = ip_route_output_ports(net, &fl4, NULL,
				   opt->dst_addr.sin_addr.s_addr,
				   opt->src_addr.sin_addr.s_addr,
				   0, 0, IPPROTO_GRE,
				   RT_TOS(0), 0);
	if (IS_ERR(rt))
		goto tx_error;

	tdev = rt->dst.dev;

	max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(*iph) + sizeof(*hdr) + 2;

	if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) {
		struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
		if (!new_skb) {
			ip_rt_put(rt);
			goto tx_error;
		}
		if (skb->sk)
			skb_set_owner_w(new_skb, skb->sk);
		consume_skb(skb);
		skb = new_skb;
	}

	data = skb->data;
	islcp = ((data[0] << 8) + data[1]) == PPP_LCP && 1 <= data[2] && data[2] <= 7;

	/* compress protocol field */
	if ((opt->ppp_flags & SC_COMP_PROT) && data[0] == 0 && !islcp)
		skb_pull(skb, 1);

	/* Put in the address/control bytes if necessary */
	if ((opt->ppp_flags & SC_COMP_AC) == 0 || islcp) {
		data = skb_push(skb, 2);
		data[0] = PPP_ALLSTATIONS;
		data[1] = PPP_UI;
	}

	len = skb->len;

	seq_recv = opt->seq_recv;

	if (opt->ack_sent == seq_recv)
		header_len -= sizeof(hdr->ack);

	/* Push down and install GRE header */
	skb_push(skb, header_len);
	hdr = (struct pptp_gre_header *)(skb->data);

	hdr->gre_hd.flags = GRE_KEY | GRE_VERSION_1 | GRE_SEQ;
	hdr->gre_hd.protocol = GRE_PROTO_PPP;
	hdr->call_id = htons(opt->dst_addr.call_id);

	hdr->seq = htonl(++opt->seq_sent);
	if (opt->ack_sent != seq_recv)	{
		/* send ack with this message */
		hdr->gre_hd.flags |= GRE_ACK;
		hdr->ack  = htonl(seq_recv);
		opt->ack_sent = seq_recv;
	}
	hdr->payload_len = htons(len);

	/*	Push down and install the IP header. */

	skb_reset_transport_header(skb);
	skb_push(skb, sizeof(*iph));
	skb_reset_network_header(skb);
	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
	IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | IPSKB_REROUTED);

	iph =	ip_hdr(skb);
	iph->version =	4;
	iph->ihl =	sizeof(struct iphdr) >> 2;
	if (ip_dont_fragment(sk, &rt->dst))
		iph->frag_off	=	htons(IP_DF);
	else
		iph->frag_off	=	0;
	iph->protocol = IPPROTO_GRE;
	iph->tos      = 0;
	iph->daddr    = fl4.daddr;
	iph->saddr    = fl4.saddr;
	iph->ttl      = ip4_dst_hoplimit(&rt->dst);
	iph->tot_len  = htons(skb->len);

	skb_dst_drop(skb);
	skb_dst_set(skb, &rt->dst);

	nf_reset(skb);

	skb->ip_summed = CHECKSUM_NONE;
	ip_select_ident(net, skb, NULL);
	ip_send_check(iph);

	ip_local_out(net, skb->sk, skb);
	return 1;

tx_error:
	kfree_skb(skb);
	return 1;
}

static int pptp_rcv_core(struct sock *sk, struct sk_buff *skb)
{
	struct pppox_sock *po = pppox_sk(sk);
	struct pptp_opt *opt = &po->proto.pptp;
	int headersize, payload_len, seq;
	__u8 *payload;
	struct pptp_gre_header *header;

	if (!(sk->sk_state & PPPOX_CONNECTED)) {
		if (sock_queue_rcv_skb(sk, skb))
			goto drop;
		return NET_RX_SUCCESS;
	}

	header = (struct pptp_gre_header *)(skb->data);
	headersize  = sizeof(*header);

	/* test if acknowledgement present */
	if (GRE_IS_ACK(header->gre_hd.flags)) {
		__u32 ack;

		if (!pskb_may_pull(skb, headersize))
			goto drop;
		header = (struct pptp_gre_header *)(skb->data);

		/* ack in different place if S = 0 */
		ack = GRE_IS_SEQ(header->gre_hd.flags) ? header->ack : header->seq;

		ack = ntohl(ack);

		if (ack > opt->ack_recv)
			opt->ack_recv = ack;
		/* also handle sequence number wrap-around  */
		if (WRAPPED(ack, opt->ack_recv))
			opt->ack_recv = ack;
	} else {
		headersize -= sizeof(header->ack);
	}
	/* test if payload present */
	if (!GRE_IS_SEQ(header->gre_hd.flags))
		goto drop;

	payload_len = ntohs(header->payload_len);
	seq         = ntohl(header->seq);

	/* check for incomplete packet (length smaller than expected) */
	if (!pskb_may_pull(skb, headersize + payload_len))
		goto drop;

	payload = skb->data + headersize;
	/* check for expected sequence number */
	if (seq < opt->seq_recv + 1 || WRAPPED(opt->seq_recv, seq)) {
		if ((payload[0] == PPP_ALLSTATIONS) && (payload[1] == PPP_UI) &&
				(PPP_PROTOCOL(payload) == PPP_LCP) &&
				((payload[4] == PPP_LCP_ECHOREQ) || (payload[4] == PPP_LCP_ECHOREP)))
			goto allow_packet;
	} else {
		opt->seq_recv = seq;
allow_packet:
		skb_pull(skb, headersize);

		if (payload[0] == PPP_ALLSTATIONS && payload[1] == PPP_UI) {
			/* chop off address/control */
			if (skb->len < 3)
				goto drop;
			skb_pull(skb, 2);
		}

		if ((*skb->data) & 1) {
			/* protocol is compressed */
			skb_push(skb, 1)[0] = 0;
		}

		skb->ip_summed = CHECKSUM_NONE;
		skb_set_network_header(skb, skb->head-skb->data);
		ppp_input(&po->chan, skb);

		return NET_RX_SUCCESS;
	}
drop:
	kfree_skb(skb);
	return NET_RX_DROP;
}

static int pptp_rcv(struct sk_buff *skb)
{
	struct pppox_sock *po;
	struct pptp_gre_header *header;
	struct iphdr *iph;

	if (skb->pkt_type != PACKET_HOST)
		goto drop;

	if (!pskb_may_pull(skb, 12))
		goto drop;

	iph = ip_hdr(skb);

	header = (struct pptp_gre_header *)skb->data;

	if (header->gre_hd.protocol != GRE_PROTO_PPP || /* PPTP-GRE protocol for PPTP */
		GRE_IS_CSUM(header->gre_hd.flags) ||    /* flag CSUM should be clear */
		GRE_IS_ROUTING(header->gre_hd.flags) || /* flag ROUTING should be clear */
		!GRE_IS_KEY(header->gre_hd.flags) ||    /* flag KEY should be set */
		(header->gre_hd.flags & GRE_FLAGS))     /* flag Recursion Ctrl should be clear */
		/* if invalid, discard this packet */
		goto drop;

	po = lookup_chan(htons(header->call_id), iph->saddr);
	if (po) {
		skb_dst_drop(skb);
		nf_reset(skb);
		return sk_receive_skb(sk_pppox(po), skb, 0);
	}
drop:
	kfree_skb(skb);
	return NET_RX_DROP;
}

static int pptp_bind(struct socket *sock, struct sockaddr *uservaddr,
	int sockaddr_len)
{
	struct sock *sk = sock->sk;
	struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr;
	struct pppox_sock *po = pppox_sk(sk);
	int error = 0;

	if (sockaddr_len < sizeof(struct sockaddr_pppox))
		return -EINVAL;

	lock_sock(sk);

	if (sk->sk_state & PPPOX_DEAD) {
		error = -EALREADY;
		goto out;
	}

	if (sk->sk_state & PPPOX_BOUND) {
		error = -EBUSY;
		goto out;
	}

	if (add_chan(po, &sp->sa_addr.pptp))
		error = -EBUSY;
	else
		sk->sk_state |= PPPOX_BOUND;

out:
	release_sock(sk);
	return error;
}

static int pptp_connect(struct socket *sock, struct sockaddr *uservaddr,
	int sockaddr_len, int flags)
{
	struct sock *sk = sock->sk;
	struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr;
	struct pppox_sock *po = pppox_sk(sk);
	struct pptp_opt *opt = &po->proto.pptp;
	struct rtable *rt;
	struct flowi4 fl4;
	int error = 0;

	if (sockaddr_len < sizeof(struct sockaddr_pppox))
		return -EINVAL;

	if (sp->sa_protocol != PX_PROTO_PPTP)
		return -EINVAL;

	if (lookup_chan_dst(sp->sa_addr.pptp.call_id, sp->sa_addr.pptp.sin_addr.s_addr))
		return -EALREADY;

	lock_sock(sk);
	/* Check for already bound sockets */
	if (sk->sk_state & PPPOX_CONNECTED) {
		error = -EBUSY;
		goto end;
	}

	/* Check for already disconnected sockets, on attempts to disconnect */
	if (sk->sk_state & PPPOX_DEAD) {
		error = -EALREADY;
		goto end;
	}

	if (!opt->src_addr.sin_addr.s_addr || !sp->sa_addr.pptp.sin_addr.s_addr) {
		error = -EINVAL;
		goto end;
	}

	po->chan.private = sk;
	po->chan.ops = &pptp_chan_ops;

	rt = ip_route_output_ports(sock_net(sk), &fl4, sk,
				   opt->dst_addr.sin_addr.s_addr,
				   opt->src_addr.sin_addr.s_addr,
				   0, 0,
				   IPPROTO_GRE, RT_CONN_FLAGS(sk), 0);
	if (IS_ERR(rt)) {
		error = -EHOSTUNREACH;
		goto end;
	}
	sk_setup_caps(sk, &rt->dst);

	po->chan.mtu = dst_mtu(&rt->dst);
	if (!po->chan.mtu)
		po->chan.mtu = PPP_MRU;
	ip_rt_put(rt);
	po->chan.mtu -= PPTP_HEADER_OVERHEAD;

	po->chan.hdrlen = 2 + sizeof(struct pptp_gre_header);
	error = ppp_register_channel(&po->chan);
	if (error) {
		pr_err("PPTP: failed to register PPP channel (%d)\n", error);
		goto end;
	}

	opt->dst_addr = sp->sa_addr.pptp;
	sk->sk_state |= PPPOX_CONNECTED;

 end:
	release_sock(sk);
	return error;
}

static int pptp_getname(struct socket *sock, struct sockaddr *uaddr,
	int *usockaddr_len, int peer)
{
	int len = sizeof(struct sockaddr_pppox);
	struct sockaddr_pppox sp;

	memset(&sp.sa_addr, 0, sizeof(sp.sa_addr));

	sp.sa_family    = AF_PPPOX;
	sp.sa_protocol  = PX_PROTO_PPTP;
	sp.sa_addr.pptp = pppox_sk(sock->sk)->proto.pptp.src_addr;

	memcpy(uaddr, &sp, len);

	*usockaddr_len = len;

	return 0;
}

static int pptp_release(struct socket *sock)
{
	struct sock *sk = sock->sk;
	struct pppox_sock *po;
	struct pptp_opt *opt;
	int error = 0;

	if (!sk)
		return 0;

	lock_sock(sk);

	if (sock_flag(sk, SOCK_DEAD)) {
		release_sock(sk);
		return -EBADF;
	}

	po = pppox_sk(sk);
	opt = &po->proto.pptp;
	del_chan(po);

	pppox_unbind_sock(sk);
	sk->sk_state = PPPOX_DEAD;

	sock_orphan(sk);
	sock->sk = NULL;

	release_sock(sk);
	sock_put(sk);

	return error;
}

static void pptp_sock_destruct(struct sock *sk)
{
	if (!(sk->sk_state & PPPOX_DEAD)) {
		del_chan(pppox_sk(sk));
		pppox_unbind_sock(sk);
	}
	skb_queue_purge(&sk->sk_receive_queue);
}

static int pptp_create(struct net *net, struct socket *sock, int kern)
{
	int error = -ENOMEM;
	struct sock *sk;
	struct pppox_sock *po;
	struct pptp_opt *opt;

	sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pptp_sk_proto, kern);
	if (!sk)
		goto out;

	sock_init_data(sock, sk);

	sock->state = SS_UNCONNECTED;
	sock->ops   = &pptp_ops;

	sk->sk_backlog_rcv = pptp_rcv_core;
	sk->sk_state       = PPPOX_NONE;
	sk->sk_type        = SOCK_STREAM;
	sk->sk_family      = PF_PPPOX;
	sk->sk_protocol    = PX_PROTO_PPTP;
	sk->sk_destruct    = pptp_sock_destruct;

	po = pppox_sk(sk);
	opt = &po->proto.pptp;

	opt->seq_sent = 0; opt->seq_recv = 0xffffffff;
	opt->ack_recv = 0; opt->ack_sent = 0xffffffff;

	error = 0;
out:
	return error;
}

static int pptp_ppp_ioctl(struct ppp_channel *chan, unsigned int cmd,
	unsigned long arg)
{
	struct sock *sk = (struct sock *) chan->private;
	struct pppox_sock *po = pppox_sk(sk);
	struct pptp_opt *opt = &po->proto.pptp;
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int err, val;

	err = -EFAULT;
	switch (cmd) {
	case PPPIOCGFLAGS:
		val = opt->ppp_flags;
		if (put_user(val, p))
			break;
		err = 0;
		break;
	case PPPIOCSFLAGS:
		if (get_user(val, p))
			break;
		opt->ppp_flags = val & ~SC_RCV_BITS;
		err = 0;
		break;
	default:
		err = -ENOTTY;
	}

	return err;
}

static const struct ppp_channel_ops pptp_chan_ops = {
	.start_xmit = pptp_xmit,
	.ioctl      = pptp_ppp_ioctl,
};

static struct proto pptp_sk_proto __read_mostly = {
	.name     = "PPTP",
	.owner    = THIS_MODULE,
	.obj_size = sizeof(struct pppox_sock),
};

static const struct proto_ops pptp_ops = {
	.family     = AF_PPPOX,
	.owner      = THIS_MODULE,
	.release    = pptp_release,
	.bind       = pptp_bind,
	.connect    = pptp_connect,
	.socketpair = sock_no_socketpair,
	.accept     = sock_no_accept,
	.getname    = pptp_getname,
	.poll       = sock_no_poll,
	.listen     = sock_no_listen,
	.shutdown   = sock_no_shutdown,
	.setsockopt = sock_no_setsockopt,
	.getsockopt = sock_no_getsockopt,
	.sendmsg    = sock_no_sendmsg,
	.recvmsg    = sock_no_recvmsg,
	.mmap       = sock_no_mmap,
	.ioctl      = pppox_ioctl,
};

static const struct pppox_proto pppox_pptp_proto = {
	.create = pptp_create,
	.owner  = THIS_MODULE,
};

static const struct gre_protocol gre_pptp_protocol = {
	.handler = pptp_rcv,
};

static int __init pptp_init_module(void)
{
	int err = 0;
	pr_info("PPTP driver version " PPTP_DRIVER_VERSION "\n");

	callid_sock = vzalloc((MAX_CALLID + 1) * sizeof(void *));
	if (!callid_sock)
		return -ENOMEM;

	err = gre_add_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
	if (err) {
		pr_err("PPTP: can't add gre protocol\n");
		goto out_mem_free;
	}

	err = proto_register(&pptp_sk_proto, 0);
	if (err) {
		pr_err("PPTP: can't register sk_proto\n");
		goto out_gre_del_protocol;
	}

	err = register_pppox_proto(PX_PROTO_PPTP, &pppox_pptp_proto);
	if (err) {
		pr_err("PPTP: can't register pppox_proto\n");
		goto out_unregister_sk_proto;
	}

	return 0;

out_unregister_sk_proto:
	proto_unregister(&pptp_sk_proto);
out_gre_del_protocol:
	gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
out_mem_free:
	vfree(callid_sock);

	return err;
}

static void __exit pptp_exit_module(void)
{
	unregister_pppox_proto(PX_PROTO_PPTP);
	proto_unregister(&pptp_sk_proto);
	gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
	vfree(callid_sock);
}

module_init(pptp_init_module);
module_exit(pptp_exit_module);

MODULE_DESCRIPTION("Point-to-Point Tunneling Protocol");
MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_PPTP);
Commit	Line	Data
00959ade DK	1	/*
	2	* Point-to-Point Tunneling Protocol for Linux
	3	*
	4	* Authors: Dmitry Kozlov <xeb@mail.ru>
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*
	11	*/
	12
	13	#include <linux/string.h>
	14	#include <linux/module.h>
	15	#include <linux/kernel.h>
	16	#include <linux/slab.h>
	17	#include <linux/errno.h>
	18	#include <linux/netdevice.h>
	19	#include <linux/net.h>
	20	#include <linux/skbuff.h>
	21	#include <linux/vmalloc.h>
	22	#include <linux/init.h>
	23	#include <linux/ppp_channel.h>
	24	#include <linux/ppp_defs.h>
	25	#include <linux/if_pppox.h>
bf7daebb	26	#include <linux/ppp-ioctl.h>
00959ade DK	27	#include <linux/notifier.h>
	28	#include <linux/file.h>
	29	#include <linux/in.h>
	30	#include <linux/ip.h>
00959ade DK	31	#include <linux/rcupdate.h>
	32	#include <linux/spinlock.h>
	33
	34	#include <net/sock.h>
	35	#include <net/protocol.h>
	36	#include <net/ip.h>
	37	#include <net/icmp.h>
	38	#include <net/route.h>
	39	#include <net/gre.h>
ab10dccb	40	#include <net/pptp.h>
00959ade DK	41
	42	#include <linux/uaccess.h>
	43
	44	#define PPTP_DRIVER_VERSION "0.8.5"
	45
	46	#define MAX_CALLID 65535
	47
	48	static DECLARE_BITMAP(callid_bitmap, MAX_CALLID + 1);
469230d1	49	static struct pppox_sock __rcu **callid_sock;
00959ade DK	50
	51	static DEFINE_SPINLOCK(chan_lock);
	52
	53	static struct proto pptp_sk_proto __read_mostly;
756e64a0	54	static const struct ppp_channel_ops pptp_chan_ops;
00959ade DK	55	static const struct proto_ops pptp_ops;
00959ade DK	56
00959ade DK	57	static struct pppox_sock *lookup_chan(u16 call_id, __be32 s_addr)
	58	{
	59	struct pppox_sock *sock;
	60	struct pptp_opt *opt;
	61
	62	rcu_read_lock();
	63	sock = rcu_dereference(callid_sock[call_id]);
	64	if (sock) {
	65	opt = &sock->proto.pptp;
	66	if (opt->dst_addr.sin_addr.s_addr != s_addr)
	67	sock = NULL;
	68	else
	69	sock_hold(sk_pppox(sock));
	70	}
	71	rcu_read_unlock();
	72
	73	return sock;
	74	}
	75
	76	static int lookup_chan_dst(u16 call_id, __be32 d_addr)
	77	{
	78	struct pppox_sock *sock;
	79	struct pptp_opt *opt;
	80	int i;
	81
	82	rcu_read_lock();
99427747 AM	83	i = 1;
99427747 AM	84	for_each_set_bit_from(i, callid_bitmap, MAX_CALLID) {
00959ade DK	85	sock = rcu_dereference(callid_sock[i]);
	86	if (!sock)
	87	continue;
	88	opt = &sock->proto.pptp;
	89	if (opt->dst_addr.call_id == call_id &&
	90	opt->dst_addr.sin_addr.s_addr == d_addr)
	91	break;
	92	}
	93	rcu_read_unlock();
	94
	95	return i < MAX_CALLID;
	96	}
	97
9a368aff HFS	98	static int add_chan(struct pppox_sock *sock,
9a368aff HFS	99	struct pptp_addr *sa)
00959ade DK	100	{
	101	static int call_id;
	102
	103	spin_lock(&chan_lock);
9a368aff	104	if (!sa->call_id) {
00959ade DK	105	call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, call_id + 1);
	106	if (call_id == MAX_CALLID) {
	107	call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, 1);
	108	if (call_id == MAX_CALLID)
	109	goto out_err;
	110	}
9a368aff HFS	111	sa->call_id = call_id;
9a368aff HFS	112	} else if (test_bit(sa->call_id, callid_bitmap)) {
00959ade	113	goto out_err;
9a368aff	114	}
00959ade	115
9a368aff HFS	116	sock->proto.pptp.src_addr = *sa;
	117	set_bit(sa->call_id, callid_bitmap);
	118	rcu_assign_pointer(callid_sock[sa->call_id], sock);
00959ade DK	119	spin_unlock(&chan_lock);
	120
	121	return 0;
	122
	123	out_err:
	124	spin_unlock(&chan_lock);
	125	return -1;
	126	}
	127
	128	static void del_chan(struct pppox_sock *sock)
	129	{
	130	spin_lock(&chan_lock);
	131	clear_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap);
2cfa5a04	132	RCU_INIT_POINTER(callid_sock[sock->proto.pptp.src_addr.call_id], NULL);
00959ade DK	133	spin_unlock(&chan_lock);
	134	synchronize_rcu();
	135	}
	136
	137	static int pptp_xmit(struct ppp_channel chan, struct sk_buff skb)
	138	{
	139	struct sock sk = (struct sock ) chan->private;
	140	struct pppox_sock *po = pppox_sk(sk);
a7093fef	141	struct net *net = sock_net(sk);
00959ade DK	142	struct pptp_opt *opt = &po->proto.pptp;
	143	struct pptp_gre_header *hdr;
	144	unsigned int header_len = sizeof(*hdr);
31e4543d	145	struct flowi4 fl4;
00959ade DK	146	int islcp;
	147	int len;
	148	unsigned char *data;
	149	__u32 seq_recv;
	150
	151
	152	struct rtable *rt;
	153	struct net_device *tdev;
	154	struct iphdr *iph;
	155	int max_headroom;
	156
	157	if (sk_pppox(po)->sk_state & PPPOX_DEAD)
	158	goto tx_error;
	159
a7093fef	160	rt = ip_route_output_ports(net, &fl4, NULL,
78fbfd8a DM	161	opt->dst_addr.sin_addr.s_addr,
	162	opt->src_addr.sin_addr.s_addr,
	163	0, 0, IPPROTO_GRE,
	164	RT_TOS(0), 0);
	165	if (IS_ERR(rt))
	166	goto tx_error;
	167
00959ade DK	168	tdev = rt->dst.dev;
	169
	170	max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(iph) + sizeof(hdr) + 2;
	171
	172	if (skb_headroom(skb) < max_headroom \|\| skb_cloned(skb) \|\| skb_shared(skb)) {
	173	struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
	174	if (!new_skb) {
	175	ip_rt_put(rt);
	176	goto tx_error;
	177	}
	178	if (skb->sk)
	179	skb_set_owner_w(new_skb, skb->sk);
968d7018	180	consume_skb(skb);
00959ade DK	181	skb = new_skb;
	182	}
	183
	184	data = skb->data;
	185	islcp = ((data[0] << 8) + data[1]) == PPP_LCP && 1 <= data[2] && data[2] <= 7;
	186
	187	/* compress protocol field */
	188	if ((opt->ppp_flags & SC_COMP_PROT) && data[0] == 0 && !islcp)
	189	skb_pull(skb, 1);
	190
	191	/* Put in the address/control bytes if necessary */
	192	if ((opt->ppp_flags & SC_COMP_AC) == 0 \|\| islcp) {
	193	data = skb_push(skb, 2);
	194	data[0] = PPP_ALLSTATIONS;
	195	data[1] = PPP_UI;
	196	}
	197
	198	len = skb->len;
	199
	200	seq_recv = opt->seq_recv;
	201
	202	if (opt->ack_sent == seq_recv)
	203	header_len -= sizeof(hdr->ack);
	204
	205	/* Push down and install GRE header */
	206	skb_push(skb, header_len);
	207	hdr = (struct pptp_gre_header *)(skb->data);
	208
03459345 GF	209	hdr->gre_hd.flags = GRE_KEY \| GRE_VERSION_1 \| GRE_SEQ;
	210	hdr->gre_hd.protocol = GRE_PROTO_PPP;
	211	hdr->call_id = htons(opt->dst_addr.call_id);
00959ade	212
03459345	213	hdr->seq = htonl(++opt->seq_sent);
00959ade DK	214	if (opt->ack_sent != seq_recv) {
00959ade DK	215	/* send ack with this message */
03459345	216	hdr->gre_hd.flags \|= GRE_ACK;
00959ade DK	217	hdr->ack = htonl(seq_recv);
	218	opt->ack_sent = seq_recv;
	219	}
	220	hdr->payload_len = htons(len);
	221
	222	/* Push down and install the IP header. */
	223
	224	skb_reset_transport_header(skb);
	225	skb_push(skb, sizeof(*iph));
	226	skb_reset_network_header(skb);
	227	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
	228	IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE \| IPSKB_XFRM_TRANSFORMED \| IPSKB_REROUTED);
	229
	230	iph = ip_hdr(skb);
	231	iph->version = 4;
	232	iph->ihl = sizeof(struct iphdr) >> 2;
	233	if (ip_dont_fragment(sk, &rt->dst))
	234	iph->frag_off = htons(IP_DF);
	235	else
	236	iph->frag_off = 0;
	237	iph->protocol = IPPROTO_GRE;
	238	iph->tos = 0;
28c90da0 DM	239	iph->daddr = fl4.daddr;
28c90da0 DM	240	iph->saddr = fl4.saddr;
323e126f	241	iph->ttl = ip4_dst_hoplimit(&rt->dst);
00959ade DK	242	iph->tot_len = htons(skb->len);
	243
	244	skb_dst_drop(skb);
	245	skb_dst_set(skb, &rt->dst);
	246
	247	nf_reset(skb);
	248
	249	skb->ip_summed = CHECKSUM_NONE;
a7093fef	250	ip_select_ident(net, skb, NULL);
00959ade DK	251	ip_send_check(iph);
00959ade DK	252
33224b16	253	ip_local_out(net, skb->sk, skb);
8bae8bd6	254	return 1;
00959ade DK	255
00959ade DK	256	tx_error:
8bae8bd6	257	kfree_skb(skb);
00959ade DK	258	return 1;
	259	}
	260
	261	static int pptp_rcv_core(struct sock sk, struct sk_buff skb)
	262	{
	263	struct pppox_sock *po = pppox_sk(sk);
	264	struct pptp_opt *opt = &po->proto.pptp;
	265	int headersize, payload_len, seq;
	266	__u8 *payload;
	267	struct pptp_gre_header *header;
	268
	269	if (!(sk->sk_state & PPPOX_CONNECTED)) {
	270	if (sock_queue_rcv_skb(sk, skb))
	271	goto drop;
	272	return NET_RX_SUCCESS;
	273	}
	274
	275	header = (struct pptp_gre_header *)(skb->data);
4ea2739e	276	headersize = sizeof(*header);
00959ade DK	277
00959ade DK	278	/* test if acknowledgement present */
03459345	279	if (GRE_IS_ACK(header->gre_hd.flags)) {
4ea2739e ED	280	__u32 ack;
	281
	282	if (!pskb_may_pull(skb, headersize))
	283	goto drop;
	284	header = (struct pptp_gre_header *)(skb->data);
	285
	286	/* ack in different place if S = 0 */
03459345	287	ack = GRE_IS_SEQ(header->gre_hd.flags) ? header->ack : header->seq;
00959ade DK	288
	289	ack = ntohl(ack);
	290
	291	if (ack > opt->ack_recv)
	292	opt->ack_recv = ack;
	293	/* also handle sequence number wrap-around */
	294	if (WRAPPED(ack, opt->ack_recv))
	295	opt->ack_recv = ack;
4ea2739e ED	296	} else {
4ea2739e ED	297	headersize -= sizeof(header->ack);
00959ade	298	}
00959ade	299	/* test if payload present */
03459345	300	if (!GRE_IS_SEQ(header->gre_hd.flags))
00959ade DK	301	goto drop;
00959ade DK	302
00959ade DK	303	payload_len = ntohs(header->payload_len);
	304	seq = ntohl(header->seq);
	305
00959ade	306	/* check for incomplete packet (length smaller than expected) */
4ea2739e	307	if (!pskb_may_pull(skb, headersize + payload_len))
00959ade DK	308	goto drop;
	309
	310	payload = skb->data + headersize;
	311	/* check for expected sequence number */
	312	if (seq < opt->seq_recv + 1 \|\| WRAPPED(opt->seq_recv, seq)) {
	313	if ((payload[0] == PPP_ALLSTATIONS) && (payload[1] == PPP_UI) &&
	314	(PPP_PROTOCOL(payload) == PPP_LCP) &&
	315	((payload[4] == PPP_LCP_ECHOREQ) \|\| (payload[4] == PPP_LCP_ECHOREP)))
	316	goto allow_packet;
	317	} else {
	318	opt->seq_recv = seq;
	319	allow_packet:
	320	skb_pull(skb, headersize);
	321
	322	if (payload[0] == PPP_ALLSTATIONS && payload[1] == PPP_UI) {
	323	/* chop off address/control */
	324	if (skb->len < 3)
	325	goto drop;
	326	skb_pull(skb, 2);
	327	}
	328
	329	if ((*skb->data) & 1) {
	330	/* protocol is compressed */
	331	skb_push(skb, 1)[0] = 0;
	332	}
	333
	334	skb->ip_summed = CHECKSUM_NONE;
	335	skb_set_network_header(skb, skb->head-skb->data);
	336	ppp_input(&po->chan, skb);
	337
	338	return NET_RX_SUCCESS;
	339	}
	340	drop:
	341	kfree_skb(skb);
	342	return NET_RX_DROP;
	343	}
	344
	345	static int pptp_rcv(struct sk_buff *skb)
	346	{
	347	struct pppox_sock *po;
	348	struct pptp_gre_header *header;
	349	struct iphdr *iph;
	350
	351	if (skb->pkt_type != PACKET_HOST)
	352	goto drop;
	353
	354	if (!pskb_may_pull(skb, 12))
	355	goto drop;
	356
	357	iph = ip_hdr(skb);
	358
	359	header = (struct pptp_gre_header *)skb->data;
	360
03459345 GF	361	if (header->gre_hd.protocol != GRE_PROTO_PPP \|\| /* PPTP-GRE protocol for PPTP */
	362	GRE_IS_CSUM(header->gre_hd.flags) \|\| /* flag CSUM should be clear */
	363	GRE_IS_ROUTING(header->gre_hd.flags) \|\| /* flag ROUTING should be clear */
	364	!GRE_IS_KEY(header->gre_hd.flags) \|\| /* flag KEY should be set */
	365	(header->gre_hd.flags & GRE_FLAGS)) /* flag Recursion Ctrl should be clear */
00959ade DK	366	/* if invalid, discard this packet */
	367	goto drop;
	368
	369	po = lookup_chan(htons(header->call_id), iph->saddr);
	370	if (po) {
	371	skb_dst_drop(skb);
	372	nf_reset(skb);
	373	return sk_receive_skb(sk_pppox(po), skb, 0);
	374	}
	375	drop:
	376	kfree_skb(skb);
	377	return NET_RX_DROP;
	378	}
	379
	380	static int pptp_bind(struct socket sock, struct sockaddr uservaddr,
	381	int sockaddr_len)
	382	{
	383	struct sock *sk = sock->sk;
	384	struct sockaddr_pppox sp = (struct sockaddr_pppox ) uservaddr;
	385	struct pppox_sock *po = pppox_sk(sk);
00959ade DK	386	int error = 0;
00959ade DK	387
09ccfd23 WC	388	if (sockaddr_len < sizeof(struct sockaddr_pppox))
	389	return -EINVAL;
	390
00959ade DK	391	lock_sock(sk);
00959ade DK	392
9a368aff HFS	393	if (sk->sk_state & PPPOX_DEAD) {
	394	error = -EALREADY;
	395	goto out;
	396	}
	397
	398	if (sk->sk_state & PPPOX_BOUND) {
00959ade	399	error = -EBUSY;
9a368aff HFS	400	goto out;
	401	}
	402
	403	if (add_chan(po, &sp->sa_addr.pptp))
	404	error = -EBUSY;
	405	else
	406	sk->sk_state \|= PPPOX_BOUND;
00959ade	407
9a368aff	408	out:
00959ade DK	409	release_sock(sk);
	410	return error;
	411	}
	412
	413	static int pptp_connect(struct socket sock, struct sockaddr uservaddr,
	414	int sockaddr_len, int flags)
	415	{
	416	struct sock *sk = sock->sk;
	417	struct sockaddr_pppox sp = (struct sockaddr_pppox ) uservaddr;
	418	struct pppox_sock *po = pppox_sk(sk);
	419	struct pptp_opt *opt = &po->proto.pptp;
	420	struct rtable *rt;
31e4543d	421	struct flowi4 fl4;
00959ade DK	422	int error = 0;
00959ade DK	423
09ccfd23 WC	424	if (sockaddr_len < sizeof(struct sockaddr_pppox))
	425	return -EINVAL;
	426
00959ade DK	427	if (sp->sa_protocol != PX_PROTO_PPTP)
	428	return -EINVAL;
	429
	430	if (lookup_chan_dst(sp->sa_addr.pptp.call_id, sp->sa_addr.pptp.sin_addr.s_addr))
	431	return -EALREADY;
	432
	433	lock_sock(sk);
	434	/* Check for already bound sockets */
	435	if (sk->sk_state & PPPOX_CONNECTED) {
	436	error = -EBUSY;
	437	goto end;
	438	}
	439
	440	/* Check for already disconnected sockets, on attempts to disconnect */
	441	if (sk->sk_state & PPPOX_DEAD) {
	442	error = -EALREADY;
	443	goto end;
	444	}
	445
	446	if (!opt->src_addr.sin_addr.s_addr \|\| !sp->sa_addr.pptp.sin_addr.s_addr) {
	447	error = -EINVAL;
	448	goto end;
	449	}
	450
	451	po->chan.private = sk;
	452	po->chan.ops = &pptp_chan_ops;
	453
08252b32	454	rt = ip_route_output_ports(sock_net(sk), &fl4, sk,
78fbfd8a DM	455	opt->dst_addr.sin_addr.s_addr,
	456	opt->src_addr.sin_addr.s_addr,
	457	0, 0,
	458	IPPROTO_GRE, RT_CONN_FLAGS(sk), 0);
	459	if (IS_ERR(rt)) {
	460	error = -EHOSTUNREACH;
	461	goto end;
00959ade	462	}
78fbfd8a DM	463	sk_setup_caps(sk, &rt->dst);
78fbfd8a DM	464
00959ade DK	465	po->chan.mtu = dst_mtu(&rt->dst);
00959ade DK	466	if (!po->chan.mtu)
bf7daebb	467	po->chan.mtu = PPP_MRU;
00959ade DK	468	ip_rt_put(rt);
	469	po->chan.mtu -= PPTP_HEADER_OVERHEAD;
	470
	471	po->chan.hdrlen = 2 + sizeof(struct pptp_gre_header);
	472	error = ppp_register_channel(&po->chan);
	473	if (error) {
	474	pr_err("PPTP: failed to register PPP channel (%d)\n", error);
	475	goto end;
	476	}
	477
	478	opt->dst_addr = sp->sa_addr.pptp;
9a368aff	479	sk->sk_state \|= PPPOX_CONNECTED;
00959ade DK	480
	481	end:
	482	release_sock(sk);
	483	return error;
	484	}
	485
	486	static int pptp_getname(struct socket sock, struct sockaddr uaddr,
	487	int *usockaddr_len, int peer)
	488	{
	489	int len = sizeof(struct sockaddr_pppox);
	490	struct sockaddr_pppox sp;
	491
a5f6fc28 MK	492	memset(&sp.sa_addr, 0, sizeof(sp.sa_addr));
	493
	494	sp.sa_family = AF_PPPOX;
00959ade DK	495	sp.sa_protocol = PX_PROTO_PPTP;
	496	sp.sa_addr.pptp = pppox_sk(sock->sk)->proto.pptp.src_addr;
	497
	498	memcpy(uaddr, &sp, len);
	499
	500	*usockaddr_len = len;
	501
	502	return 0;
	503	}
	504
	505	static int pptp_release(struct socket *sock)
	506	{
	507	struct sock *sk = sock->sk;
	508	struct pppox_sock *po;
	509	struct pptp_opt *opt;
	510	int error = 0;
	511
	512	if (!sk)
	513	return 0;
	514
	515	lock_sock(sk);
	516
	517	if (sock_flag(sk, SOCK_DEAD)) {
	518	release_sock(sk);
	519	return -EBADF;
	520	}
	521
	522	po = pppox_sk(sk);
	523	opt = &po->proto.pptp;
	524	del_chan(po);
	525
	526	pppox_unbind_sock(sk);
	527	sk->sk_state = PPPOX_DEAD;
	528
	529	sock_orphan(sk);
	530	sock->sk = NULL;
	531
	532	release_sock(sk);
	533	sock_put(sk);
	534
	535	return error;
	536	}
	537
	538	static void pptp_sock_destruct(struct sock *sk)
	539	{
	540	if (!(sk->sk_state & PPPOX_DEAD)) {
	541	del_chan(pppox_sk(sk));
	542	pppox_unbind_sock(sk);
	543	}
	544	skb_queue_purge(&sk->sk_receive_queue);
	545	}
	546
11aa9c28	547	static int pptp_create(struct net net, struct socket sock, int kern)
00959ade DK	548	{
	549	int error = -ENOMEM;
	550	struct sock *sk;
	551	struct pppox_sock *po;
	552	struct pptp_opt *opt;
	553
11aa9c28	554	sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pptp_sk_proto, kern);
00959ade DK	555	if (!sk)
	556	goto out;
	557
	558	sock_init_data(sock, sk);
	559
	560	sock->state = SS_UNCONNECTED;
	561	sock->ops = &pptp_ops;
	562
	563	sk->sk_backlog_rcv = pptp_rcv_core;
	564	sk->sk_state = PPPOX_NONE;
	565	sk->sk_type = SOCK_STREAM;
	566	sk->sk_family = PF_PPPOX;
	567	sk->sk_protocol = PX_PROTO_PPTP;
	568	sk->sk_destruct = pptp_sock_destruct;
	569
	570	po = pppox_sk(sk);
	571	opt = &po->proto.pptp;
	572
91dce7dd BP	573	opt->seq_sent = 0; opt->seq_recv = 0xffffffff;
91dce7dd BP	574	opt->ack_recv = 0; opt->ack_sent = 0xffffffff;
00959ade DK	575
	576	error = 0;
	577	out:
	578	return error;
	579	}
	580
	581	static int pptp_ppp_ioctl(struct ppp_channel *chan, unsigned int cmd,
	582	unsigned long arg)
	583	{
	584	struct sock sk = (struct sock ) chan->private;
	585	struct pppox_sock *po = pppox_sk(sk);
	586	struct pptp_opt *opt = &po->proto.pptp;
	587	void __user argp = (void __user )arg;
	588	int __user *p = argp;
	589	int err, val;
	590
	591	err = -EFAULT;
	592	switch (cmd) {
	593	case PPPIOCGFLAGS:
	594	val = opt->ppp_flags;
	595	if (put_user(val, p))
	596	break;
	597	err = 0;
	598	break;
	599	case PPPIOCSFLAGS:
	600	if (get_user(val, p))
	601	break;
	602	opt->ppp_flags = val & ~SC_RCV_BITS;
	603	err = 0;
	604	break;
	605	default:
	606	err = -ENOTTY;
	607	}
	608
	609	return err;
	610	}
	611
756e64a0	612	static const struct ppp_channel_ops pptp_chan_ops = {
00959ade DK	613	.start_xmit = pptp_xmit,
	614	.ioctl = pptp_ppp_ioctl,
	615	};
	616
	617	static struct proto pptp_sk_proto __read_mostly = {
	618	.name = "PPTP",
	619	.owner = THIS_MODULE,
	620	.obj_size = sizeof(struct pppox_sock),
	621	};
	622
	623	static const struct proto_ops pptp_ops = {
	624	.family = AF_PPPOX,
	625	.owner = THIS_MODULE,
	626	.release = pptp_release,
	627	.bind = pptp_bind,
	628	.connect = pptp_connect,
	629	.socketpair = sock_no_socketpair,
	630	.accept = sock_no_accept,
	631	.getname = pptp_getname,
	632	.poll = sock_no_poll,
	633	.listen = sock_no_listen,
	634	.shutdown = sock_no_shutdown,
	635	.setsockopt = sock_no_setsockopt,
	636	.getsockopt = sock_no_getsockopt,
	637	.sendmsg = sock_no_sendmsg,
	638	.recvmsg = sock_no_recvmsg,
	639	.mmap = sock_no_mmap,
	640	.ioctl = pppox_ioctl,
	641	};
	642
756e64a0	643	static const struct pppox_proto pppox_pptp_proto = {
00959ade DK	644	.create = pptp_create,
	645	.owner = THIS_MODULE,
	646	};
	647
756e64a0	648	static const struct gre_protocol gre_pptp_protocol = {
00959ade DK	649	.handler = pptp_rcv,
	650	};
	651
	652	static int __init pptp_init_module(void)
	653	{
	654	int err = 0;
	655	pr_info("PPTP driver version " PPTP_DRIVER_VERSION "\n");
	656
89bf67f1	657	callid_sock = vzalloc((MAX_CALLID + 1) * sizeof(void *));
e404decb	658	if (!callid_sock)
00959ade	659	return -ENOMEM;
00959ade DK	660
	661	err = gre_add_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
	662	if (err) {
	663	pr_err("PPTP: can't add gre protocol\n");
	664	goto out_mem_free;
	665	}
	666
	667	err = proto_register(&pptp_sk_proto, 0);
	668	if (err) {
	669	pr_err("PPTP: can't register sk_proto\n");
	670	goto out_gre_del_protocol;
	671	}
	672
	673	err = register_pppox_proto(PX_PROTO_PPTP, &pppox_pptp_proto);
	674	if (err) {
	675	pr_err("PPTP: can't register pppox_proto\n");
	676	goto out_unregister_sk_proto;
	677	}
	678
	679	return 0;
	680
	681	out_unregister_sk_proto:
	682	proto_unregister(&pptp_sk_proto);
	683	out_gre_del_protocol:
	684	gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
	685	out_mem_free:
	686	vfree(callid_sock);
	687
	688	return err;
	689	}
	690
	691	static void __exit pptp_exit_module(void)
	692	{
	693	unregister_pppox_proto(PX_PROTO_PPTP);
	694	proto_unregister(&pptp_sk_proto);
	695	gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
	696	vfree(callid_sock);
	697	}
	698
	699	module_init(pptp_init_module);
	700	module_exit(pptp_exit_module);
	701
	702	MODULE_DESCRIPTION("Point-to-Point Tunneling Protocol");
	703	MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)");
	704	MODULE_LICENSE("GPL");
681b4d88	705	MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_PPTP);