[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 <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;

#define PPP_LCP_ECHOREQ 0x09
#define PPP_LCP_ECHOREP 0x0A
#define SC_RCV_BITS	(SC_RCV_B7_1|SC_RCV_B7_0|SC_RCV_ODDP|SC_RCV_EVNP)

#define MISSING_WINDOW 20
#define WRAPPED(curseq, lastseq)\
	((((curseq) & 0xffffff00) == 0) &&\
	(((lastseq) & 0xffffff00) == 0xffffff00))

#define PPTP_GRE_PROTO  0x880B
#define PPTP_GRE_VER    0x1

#define PPTP_GRE_FLAG_C	0x80
#define PPTP_GRE_FLAG_R	0x40
#define PPTP_GRE_FLAG_K	0x20
#define PPTP_GRE_FLAG_S	0x10
#define PPTP_GRE_FLAG_A	0x80

#define PPTP_GRE_IS_C(f) ((f)&PPTP_GRE_FLAG_C)
#define PPTP_GRE_IS_R(f) ((f)&PPTP_GRE_FLAG_R)
#define PPTP_GRE_IS_K(f) ((f)&PPTP_GRE_FLAG_K)
#define PPTP_GRE_IS_S(f) ((f)&PPTP_GRE_FLAG_S)
#define PPTP_GRE_IS_A(f) ((f)&PPTP_GRE_FLAG_A)

#define PPTP_HEADER_OVERHEAD (2+sizeof(struct pptp_gre_header))
struct pptp_gre_header {
	u8  flags;
	u8  ver;
	__be16 protocol;
	__be16 payload_len;
	__be16 call_id;
	__be32 seq;
	__be32 ack;
} __packed;

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)
{
	static int call_id;

	spin_lock(&chan_lock);
	if (!sock->proto.pptp.src_addr.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;
		}
		sock->proto.pptp.src_addr.call_id = call_id;
	} else if (test_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap))
		goto out_err;

	set_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap);
	rcu_assign_pointer(callid_sock[sock->proto.pptp.src_addr.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 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(sock_net(sk), &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->flags       = PPTP_GRE_FLAG_K;
	hdr->ver         = PPTP_GRE_VER;
	hdr->protocol    = htons(PPTP_GRE_PROTO);
	hdr->call_id     = htons(opt->dst_addr.call_id);

	hdr->flags      |= PPTP_GRE_FLAG_S;
	hdr->seq         = htonl(++opt->seq_sent);
	if (opt->ack_sent != seq_recv)	{
		/* send ack with this message */
		hdr->ver |= PPTP_GRE_FLAG_A;
		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(sock_net(sk), skb, NULL);
	ip_send_check(iph);

	ip_local_out(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 (PPTP_GRE_IS_A(header->ver)) {
		__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 = PPTP_GRE_IS_S(header->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 (!PPTP_GRE_IS_S(header->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 (ntohs(header->protocol) != PPTP_GRE_PROTO || /* PPTP-GRE protocol for PPTP */
		PPTP_GRE_IS_C(header->flags) ||                /* flag C should be clear */
		PPTP_GRE_IS_R(header->flags) ||                /* flag R should be clear */
		!PPTP_GRE_IS_K(header->flags) ||               /* flag K should be set */
		(header->flags&0xF) != 0)                      /* routing and recursion ctrl = 0 */
		/* 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);
	struct pptp_opt *opt = &po->proto.pptp;
	int error = 0;

	lock_sock(sk);

	opt->src_addr = sp->sa_addr.pptp;
	if (add_chan(po))
		error = -EBUSY;

	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 (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");
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>
	40
	41	#include <linux/uaccess.h>
	42
	43	#define PPTP_DRIVER_VERSION "0.8.5"
	44
	45	#define MAX_CALLID 65535
	46
	47	static DECLARE_BITMAP(callid_bitmap, MAX_CALLID + 1);
469230d1	48	static struct pppox_sock __rcu **callid_sock;
00959ade DK	49
	50	static DEFINE_SPINLOCK(chan_lock);
	51
	52	static struct proto pptp_sk_proto __read_mostly;
756e64a0	53	static const struct ppp_channel_ops pptp_chan_ops;
00959ade DK	54	static const struct proto_ops pptp_ops;
	55
	56	#define PPP_LCP_ECHOREQ 0x09
	57	#define PPP_LCP_ECHOREP 0x0A
	58	#define SC_RCV_BITS (SC_RCV_B7_1\|SC_RCV_B7_0\|SC_RCV_ODDP\|SC_RCV_EVNP)
	59
	60	#define MISSING_WINDOW 20
	61	#define WRAPPED(curseq, lastseq)\
	62	((((curseq) & 0xffffff00) == 0) &&\
	63	(((lastseq) & 0xffffff00) == 0xffffff00))
	64
	65	#define PPTP_GRE_PROTO 0x880B
	66	#define PPTP_GRE_VER 0x1
	67
	68	#define PPTP_GRE_FLAG_C 0x80
	69	#define PPTP_GRE_FLAG_R 0x40
	70	#define PPTP_GRE_FLAG_K 0x20
	71	#define PPTP_GRE_FLAG_S 0x10
	72	#define PPTP_GRE_FLAG_A 0x80
	73
	74	#define PPTP_GRE_IS_C(f) ((f)&PPTP_GRE_FLAG_C)
	75	#define PPTP_GRE_IS_R(f) ((f)&PPTP_GRE_FLAG_R)
	76	#define PPTP_GRE_IS_K(f) ((f)&PPTP_GRE_FLAG_K)
	77	#define PPTP_GRE_IS_S(f) ((f)&PPTP_GRE_FLAG_S)
	78	#define PPTP_GRE_IS_A(f) ((f)&PPTP_GRE_FLAG_A)
	79
	80	#define PPTP_HEADER_OVERHEAD (2+sizeof(struct pptp_gre_header))
	81	struct pptp_gre_header {
	82	u8 flags;
	83	u8 ver;
ebd8b934	84	__be16 protocol;
	85	__be16 payload_len;
	86	__be16 call_id;
	87	__be32 seq;
	88	__be32 ack;
00959ade DK	89	} __packed;
	90
	91	static struct pppox_sock *lookup_chan(u16 call_id, __be32 s_addr)
	92	{
	93	struct pppox_sock *sock;
	94	struct pptp_opt *opt;
	95
	96	rcu_read_lock();
	97	sock = rcu_dereference(callid_sock[call_id]);
	98	if (sock) {
	99	opt = &sock->proto.pptp;
	100	if (opt->dst_addr.sin_addr.s_addr != s_addr)
	101	sock = NULL;
	102	else
	103	sock_hold(sk_pppox(sock));
	104	}
	105	rcu_read_unlock();
	106
	107	return sock;
	108	}
	109
	110	static int lookup_chan_dst(u16 call_id, __be32 d_addr)
	111	{
	112	struct pppox_sock *sock;
	113	struct pptp_opt *opt;
	114	int i;
	115
	116	rcu_read_lock();
99427747 AM	117	i = 1;
99427747 AM	118	for_each_set_bit_from(i, callid_bitmap, MAX_CALLID) {
00959ade DK	119	sock = rcu_dereference(callid_sock[i]);
	120	if (!sock)
	121	continue;
	122	opt = &sock->proto.pptp;
	123	if (opt->dst_addr.call_id == call_id &&
	124	opt->dst_addr.sin_addr.s_addr == d_addr)
	125	break;
	126	}
	127	rcu_read_unlock();
	128
	129	return i < MAX_CALLID;
	130	}
	131
	132	static int add_chan(struct pppox_sock *sock)
	133	{
	134	static int call_id;
	135
	136	spin_lock(&chan_lock);
	137	if (!sock->proto.pptp.src_addr.call_id) {
	138	call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, call_id + 1);
	139	if (call_id == MAX_CALLID) {
	140	call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, 1);
	141	if (call_id == MAX_CALLID)
	142	goto out_err;
	143	}
	144	sock->proto.pptp.src_addr.call_id = call_id;
	145	} else if (test_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap))
	146	goto out_err;
	147
	148	set_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap);
	149	rcu_assign_pointer(callid_sock[sock->proto.pptp.src_addr.call_id], sock);
	150	spin_unlock(&chan_lock);
	151
	152	return 0;
	153
	154	out_err:
	155	spin_unlock(&chan_lock);
	156	return -1;
	157	}
	158
	159	static void del_chan(struct pppox_sock *sock)
	160	{
	161	spin_lock(&chan_lock);
	162	clear_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap);
2cfa5a04	163	RCU_INIT_POINTER(callid_sock[sock->proto.pptp.src_addr.call_id], NULL);
00959ade DK	164	spin_unlock(&chan_lock);
	165	synchronize_rcu();
	166	}
	167
	168	static int pptp_xmit(struct ppp_channel chan, struct sk_buff skb)
	169	{
	170	struct sock sk = (struct sock ) chan->private;
	171	struct pppox_sock *po = pppox_sk(sk);
	172	struct pptp_opt *opt = &po->proto.pptp;
	173	struct pptp_gre_header *hdr;
	174	unsigned int header_len = sizeof(*hdr);
31e4543d	175	struct flowi4 fl4;
00959ade DK	176	int islcp;
	177	int len;
	178	unsigned char *data;
	179	__u32 seq_recv;
	180
	181
	182	struct rtable *rt;
	183	struct net_device *tdev;
	184	struct iphdr *iph;
	185	int max_headroom;
	186
	187	if (sk_pppox(po)->sk_state & PPPOX_DEAD)
	188	goto tx_error;
	189
08252b32	190	rt = ip_route_output_ports(sock_net(sk), &fl4, NULL,
78fbfd8a DM	191	opt->dst_addr.sin_addr.s_addr,
	192	opt->src_addr.sin_addr.s_addr,
	193	0, 0, IPPROTO_GRE,
	194	RT_TOS(0), 0);
	195	if (IS_ERR(rt))
	196	goto tx_error;
	197
00959ade DK	198	tdev = rt->dst.dev;
	199
	200	max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(iph) + sizeof(hdr) + 2;
	201
	202	if (skb_headroom(skb) < max_headroom \|\| skb_cloned(skb) \|\| skb_shared(skb)) {
	203	struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
	204	if (!new_skb) {
	205	ip_rt_put(rt);
	206	goto tx_error;
	207	}
	208	if (skb->sk)
	209	skb_set_owner_w(new_skb, skb->sk);
968d7018	210	consume_skb(skb);
00959ade DK	211	skb = new_skb;
	212	}
	213
	214	data = skb->data;
	215	islcp = ((data[0] << 8) + data[1]) == PPP_LCP && 1 <= data[2] && data[2] <= 7;
	216
	217	/* compress protocol field */
	218	if ((opt->ppp_flags & SC_COMP_PROT) && data[0] == 0 && !islcp)
	219	skb_pull(skb, 1);
	220
	221	/* Put in the address/control bytes if necessary */
	222	if ((opt->ppp_flags & SC_COMP_AC) == 0 \|\| islcp) {
	223	data = skb_push(skb, 2);
	224	data[0] = PPP_ALLSTATIONS;
	225	data[1] = PPP_UI;
	226	}
	227
	228	len = skb->len;
	229
	230	seq_recv = opt->seq_recv;
	231
	232	if (opt->ack_sent == seq_recv)
	233	header_len -= sizeof(hdr->ack);
	234
	235	/* Push down and install GRE header */
	236	skb_push(skb, header_len);
	237	hdr = (struct pptp_gre_header *)(skb->data);
	238
	239	hdr->flags = PPTP_GRE_FLAG_K;
	240	hdr->ver = PPTP_GRE_VER;
	241	hdr->protocol = htons(PPTP_GRE_PROTO);
	242	hdr->call_id = htons(opt->dst_addr.call_id);
	243
	244	hdr->flags \|= PPTP_GRE_FLAG_S;
	245	hdr->seq = htonl(++opt->seq_sent);
	246	if (opt->ack_sent != seq_recv) {
	247	/* send ack with this message */
	248	hdr->ver \|= PPTP_GRE_FLAG_A;
	249	hdr->ack = htonl(seq_recv);
	250	opt->ack_sent = seq_recv;
	251	}
	252	hdr->payload_len = htons(len);
	253
	254	/* Push down and install the IP header. */
	255
	256	skb_reset_transport_header(skb);
	257	skb_push(skb, sizeof(*iph));
	258	skb_reset_network_header(skb);
	259	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
	260	IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE \| IPSKB_XFRM_TRANSFORMED \| IPSKB_REROUTED);
	261
	262	iph = ip_hdr(skb);
	263	iph->version = 4;
	264	iph->ihl = sizeof(struct iphdr) >> 2;
	265	if (ip_dont_fragment(sk, &rt->dst))
	266	iph->frag_off = htons(IP_DF);
	267	else
	268	iph->frag_off = 0;
	269	iph->protocol = IPPROTO_GRE;
	270	iph->tos = 0;
28c90da0 DM	271	iph->daddr = fl4.daddr;
28c90da0 DM	272	iph->saddr = fl4.saddr;
323e126f	273	iph->ttl = ip4_dst_hoplimit(&rt->dst);
00959ade DK	274	iph->tot_len = htons(skb->len);
	275
	276	skb_dst_drop(skb);
	277	skb_dst_set(skb, &rt->dst);
	278
	279	nf_reset(skb);
	280
	281	skb->ip_summed = CHECKSUM_NONE;
b6a7719a	282	ip_select_ident(sock_net(sk), skb, NULL);
00959ade DK	283	ip_send_check(iph);
00959ade DK	284
e2cb77db	285	ip_local_out(skb->sk, skb);
8bae8bd6	286	return 1;
00959ade DK	287
00959ade DK	288	tx_error:
8bae8bd6	289	kfree_skb(skb);
00959ade DK	290	return 1;
	291	}
	292
	293	static int pptp_rcv_core(struct sock sk, struct sk_buff skb)
	294	{
	295	struct pppox_sock *po = pppox_sk(sk);
	296	struct pptp_opt *opt = &po->proto.pptp;
	297	int headersize, payload_len, seq;
	298	__u8 *payload;
	299	struct pptp_gre_header *header;
	300
	301	if (!(sk->sk_state & PPPOX_CONNECTED)) {
	302	if (sock_queue_rcv_skb(sk, skb))
	303	goto drop;
	304	return NET_RX_SUCCESS;
	305	}
	306
	307	header = (struct pptp_gre_header *)(skb->data);
4ea2739e	308	headersize = sizeof(*header);
00959ade DK	309
	310	/* test if acknowledgement present */
	311	if (PPTP_GRE_IS_A(header->ver)) {
4ea2739e ED	312	__u32 ack;
	313
	314	if (!pskb_may_pull(skb, headersize))
	315	goto drop;
	316	header = (struct pptp_gre_header *)(skb->data);
	317
	318	/* ack in different place if S = 0 */
	319	ack = PPTP_GRE_IS_S(header->flags) ? header->ack : header->seq;
00959ade DK	320
	321	ack = ntohl(ack);
	322
	323	if (ack > opt->ack_recv)
	324	opt->ack_recv = ack;
	325	/* also handle sequence number wrap-around */
	326	if (WRAPPED(ack, opt->ack_recv))
	327	opt->ack_recv = ack;
4ea2739e ED	328	} else {
4ea2739e ED	329	headersize -= sizeof(header->ack);
00959ade	330	}
00959ade DK	331	/* test if payload present */
	332	if (!PPTP_GRE_IS_S(header->flags))
	333	goto drop;
	334
00959ade DK	335	payload_len = ntohs(header->payload_len);
	336	seq = ntohl(header->seq);
	337
00959ade	338	/* check for incomplete packet (length smaller than expected) */
4ea2739e	339	if (!pskb_may_pull(skb, headersize + payload_len))
00959ade DK	340	goto drop;
	341
	342	payload = skb->data + headersize;
	343	/* check for expected sequence number */
	344	if (seq < opt->seq_recv + 1 \|\| WRAPPED(opt->seq_recv, seq)) {
	345	if ((payload[0] == PPP_ALLSTATIONS) && (payload[1] == PPP_UI) &&
	346	(PPP_PROTOCOL(payload) == PPP_LCP) &&
	347	((payload[4] == PPP_LCP_ECHOREQ) \|\| (payload[4] == PPP_LCP_ECHOREP)))
	348	goto allow_packet;
	349	} else {
	350	opt->seq_recv = seq;
	351	allow_packet:
	352	skb_pull(skb, headersize);
	353
	354	if (payload[0] == PPP_ALLSTATIONS && payload[1] == PPP_UI) {
	355	/* chop off address/control */
	356	if (skb->len < 3)
	357	goto drop;
	358	skb_pull(skb, 2);
	359	}
	360
	361	if ((*skb->data) & 1) {
	362	/* protocol is compressed */
	363	skb_push(skb, 1)[0] = 0;
	364	}
	365
	366	skb->ip_summed = CHECKSUM_NONE;
	367	skb_set_network_header(skb, skb->head-skb->data);
	368	ppp_input(&po->chan, skb);
	369
	370	return NET_RX_SUCCESS;
	371	}
	372	drop:
	373	kfree_skb(skb);
	374	return NET_RX_DROP;
	375	}
	376
	377	static int pptp_rcv(struct sk_buff *skb)
	378	{
	379	struct pppox_sock *po;
	380	struct pptp_gre_header *header;
	381	struct iphdr *iph;
	382
	383	if (skb->pkt_type != PACKET_HOST)
	384	goto drop;
	385
	386	if (!pskb_may_pull(skb, 12))
	387	goto drop;
	388
	389	iph = ip_hdr(skb);
	390
	391	header = (struct pptp_gre_header *)skb->data;
	392
	393	if (ntohs(header->protocol) != PPTP_GRE_PROTO \|\| /* PPTP-GRE protocol for PPTP */
	394	PPTP_GRE_IS_C(header->flags) \|\| /* flag C should be clear */
	395	PPTP_GRE_IS_R(header->flags) \|\| /* flag R should be clear */
	396	!PPTP_GRE_IS_K(header->flags) \|\| /* flag K should be set */
	397	(header->flags&0xF) != 0) /* routing and recursion ctrl = 0 */
	398	/* if invalid, discard this packet */
	399	goto drop;
	400
	401	po = lookup_chan(htons(header->call_id), iph->saddr);
	402	if (po) {
	403	skb_dst_drop(skb);
404	nf_reset(skb);
405	return sk_receive_skb(sk_pppox(po), skb, 0);
406	}
407	drop:
408	kfree_skb(skb);
409	return NET_RX_DROP;
410	}
411
412	static int pptp_bind(struct socket sock, struct sockaddr uservaddr,
413	int sockaddr_len)
414	{
415	struct sock *sk = sock->sk;
416	struct sockaddr_pppox sp = (struct sockaddr_pppox ) uservaddr;
417	struct pppox_sock *po = pppox_sk(sk);
418	struct pptp_opt *opt = &po->proto.pptp;
419	int error = 0;
420
421	lock_sock(sk);
422
423	opt->src_addr = sp->sa_addr.pptp;
a454dace	424	if (add_chan(po))
00959ade	425	error = -EBUSY;
00959ade DK	426
	427	release_sock(sk);
	428	return error;
	429	}
	430
	431	static int pptp_connect(struct socket sock, struct sockaddr uservaddr,
	432	int sockaddr_len, int flags)
	433	{
	434	struct sock *sk = sock->sk;
	435	struct sockaddr_pppox sp = (struct sockaddr_pppox ) uservaddr;
	436	struct pppox_sock *po = pppox_sk(sk);
	437	struct pptp_opt *opt = &po->proto.pptp;
	438	struct rtable *rt;
31e4543d	439	struct flowi4 fl4;
00959ade DK	440	int error = 0;
	441
	442	if (sp->sa_protocol != PX_PROTO_PPTP)
	443	return -EINVAL;
	444
	445	if (lookup_chan_dst(sp->sa_addr.pptp.call_id, sp->sa_addr.pptp.sin_addr.s_addr))
	446	return -EALREADY;
	447
	448	lock_sock(sk);
	449	/* Check for already bound sockets */
	450	if (sk->sk_state & PPPOX_CONNECTED) {
	451	error = -EBUSY;
	452	goto end;
	453	}
	454
	455	/* Check for already disconnected sockets, on attempts to disconnect */
	456	if (sk->sk_state & PPPOX_DEAD) {
	457	error = -EALREADY;
	458	goto end;
	459	}
	460
	461	if (!opt->src_addr.sin_addr.s_addr \|\| !sp->sa_addr.pptp.sin_addr.s_addr) {
	462	error = -EINVAL;
	463	goto end;
	464	}
	465
	466	po->chan.private = sk;
	467	po->chan.ops = &pptp_chan_ops;
	468
08252b32	469	rt = ip_route_output_ports(sock_net(sk), &fl4, sk,
78fbfd8a DM	470	opt->dst_addr.sin_addr.s_addr,
	471	opt->src_addr.sin_addr.s_addr,
	472	0, 0,
	473	IPPROTO_GRE, RT_CONN_FLAGS(sk), 0);
	474	if (IS_ERR(rt)) {
	475	error = -EHOSTUNREACH;
	476	goto end;
00959ade	477	}
78fbfd8a DM	478	sk_setup_caps(sk, &rt->dst);
78fbfd8a DM	479
00959ade DK	480	po->chan.mtu = dst_mtu(&rt->dst);
00959ade DK	481	if (!po->chan.mtu)
bf7daebb	482	po->chan.mtu = PPP_MRU;
00959ade DK	483	ip_rt_put(rt);
	484	po->chan.mtu -= PPTP_HEADER_OVERHEAD;
	485
	486	po->chan.hdrlen = 2 + sizeof(struct pptp_gre_header);
	487	error = ppp_register_channel(&po->chan);
	488	if (error) {
	489	pr_err("PPTP: failed to register PPP channel (%d)\n", error);
	490	goto end;
	491	}
	492
	493	opt->dst_addr = sp->sa_addr.pptp;
	494	sk->sk_state = PPPOX_CONNECTED;
	495
	496	end:
	497	release_sock(sk);
	498	return error;
	499	}
	500
	501	static int pptp_getname(struct socket sock, struct sockaddr uaddr,
	502	int *usockaddr_len, int peer)
	503	{
	504	int len = sizeof(struct sockaddr_pppox);
	505	struct sockaddr_pppox sp;
	506
a5f6fc28 MK	507	memset(&sp.sa_addr, 0, sizeof(sp.sa_addr));
	508
	509	sp.sa_family = AF_PPPOX;
00959ade DK	510	sp.sa_protocol = PX_PROTO_PPTP;
	511	sp.sa_addr.pptp = pppox_sk(sock->sk)->proto.pptp.src_addr;
	512
	513	memcpy(uaddr, &sp, len);
	514
	515	*usockaddr_len = len;
	516
	517	return 0;
	518	}
	519
	520	static int pptp_release(struct socket *sock)
	521	{
	522	struct sock *sk = sock->sk;
	523	struct pppox_sock *po;
	524	struct pptp_opt *opt;
	525	int error = 0;
	526
	527	if (!sk)
	528	return 0;
	529
	530	lock_sock(sk);
	531
	532	if (sock_flag(sk, SOCK_DEAD)) {
	533	release_sock(sk);
	534	return -EBADF;
	535	}
	536
	537	po = pppox_sk(sk);
	538	opt = &po->proto.pptp;
	539	del_chan(po);
	540
	541	pppox_unbind_sock(sk);
	542	sk->sk_state = PPPOX_DEAD;
	543
	544	sock_orphan(sk);
	545	sock->sk = NULL;
	546
	547	release_sock(sk);
	548	sock_put(sk);
	549
	550	return error;
	551	}
	552
	553	static void pptp_sock_destruct(struct sock *sk)
	554	{
	555	if (!(sk->sk_state & PPPOX_DEAD)) {
	556	del_chan(pppox_sk(sk));
	557	pppox_unbind_sock(sk);
	558	}
	559	skb_queue_purge(&sk->sk_receive_queue);
	560	}
	561
11aa9c28	562	static int pptp_create(struct net net, struct socket sock, int kern)
00959ade DK	563	{
	564	int error = -ENOMEM;
	565	struct sock *sk;
	566	struct pppox_sock *po;
	567	struct pptp_opt *opt;
	568
11aa9c28	569	sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pptp_sk_proto, kern);
00959ade DK	570	if (!sk)
	571	goto out;
	572
	573	sock_init_data(sock, sk);
	574
	575	sock->state = SS_UNCONNECTED;
	576	sock->ops = &pptp_ops;
	577
	578	sk->sk_backlog_rcv = pptp_rcv_core;
	579	sk->sk_state = PPPOX_NONE;
	580	sk->sk_type = SOCK_STREAM;
	581	sk->sk_family = PF_PPPOX;
	582	sk->sk_protocol = PX_PROTO_PPTP;
	583	sk->sk_destruct = pptp_sock_destruct;
	584
	585	po = pppox_sk(sk);
	586	opt = &po->proto.pptp;
	587
91dce7dd BP	588	opt->seq_sent = 0; opt->seq_recv = 0xffffffff;
91dce7dd BP	589	opt->ack_recv = 0; opt->ack_sent = 0xffffffff;
00959ade DK	590
	591	error = 0;
	592	out:
	593	return error;
	594	}
	595
	596	static int pptp_ppp_ioctl(struct ppp_channel *chan, unsigned int cmd,
	597	unsigned long arg)
	598	{
	599	struct sock sk = (struct sock ) chan->private;
	600	struct pppox_sock *po = pppox_sk(sk);
	601	struct pptp_opt *opt = &po->proto.pptp;
	602	void __user argp = (void __user )arg;
	603	int __user *p = argp;
	604	int err, val;
	605
	606	err = -EFAULT;
	607	switch (cmd) {
	608	case PPPIOCGFLAGS:
	609	val = opt->ppp_flags;
	610	if (put_user(val, p))
	611	break;
	612	err = 0;
	613	break;
	614	case PPPIOCSFLAGS:
	615	if (get_user(val, p))
	616	break;
	617	opt->ppp_flags = val & ~SC_RCV_BITS;
	618	err = 0;
	619	break;
	620	default:
	621	err = -ENOTTY;
	622	}
	623
	624	return err;
	625	}
	626
756e64a0	627	static const struct ppp_channel_ops pptp_chan_ops = {
00959ade DK	628	.start_xmit = pptp_xmit,
	629	.ioctl = pptp_ppp_ioctl,
	630	};
	631
	632	static struct proto pptp_sk_proto __read_mostly = {
	633	.name = "PPTP",
	634	.owner = THIS_MODULE,
	635	.obj_size = sizeof(struct pppox_sock),
	636	};
	637
	638	static const struct proto_ops pptp_ops = {
	639	.family = AF_PPPOX,
	640	.owner = THIS_MODULE,
	641	.release = pptp_release,
	642	.bind = pptp_bind,
	643	.connect = pptp_connect,
	644	.socketpair = sock_no_socketpair,
	645	.accept = sock_no_accept,
	646	.getname = pptp_getname,
	647	.poll = sock_no_poll,
	648	.listen = sock_no_listen,
	649	.shutdown = sock_no_shutdown,
	650	.setsockopt = sock_no_setsockopt,
	651	.getsockopt = sock_no_getsockopt,
	652	.sendmsg = sock_no_sendmsg,
	653	.recvmsg = sock_no_recvmsg,
	654	.mmap = sock_no_mmap,
	655	.ioctl = pppox_ioctl,
	656	};
	657
756e64a0	658	static const struct pppox_proto pppox_pptp_proto = {
00959ade DK	659	.create = pptp_create,
	660	.owner = THIS_MODULE,
	661	};
	662
756e64a0	663	static const struct gre_protocol gre_pptp_protocol = {
00959ade DK	664	.handler = pptp_rcv,
	665	};
	666
	667	static int __init pptp_init_module(void)
	668	{
	669	int err = 0;
	670	pr_info("PPTP driver version " PPTP_DRIVER_VERSION "\n");
	671
89bf67f1	672	callid_sock = vzalloc((MAX_CALLID + 1) * sizeof(void *));
e404decb	673	if (!callid_sock)
00959ade	674	return -ENOMEM;
00959ade DK	675
	676	err = gre_add_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
	677	if (err) {
	678	pr_err("PPTP: can't add gre protocol\n");
	679	goto out_mem_free;
	680	}
	681
	682	err = proto_register(&pptp_sk_proto, 0);
	683	if (err) {
	684	pr_err("PPTP: can't register sk_proto\n");
	685	goto out_gre_del_protocol;
	686	}
	687
	688	err = register_pppox_proto(PX_PROTO_PPTP, &pppox_pptp_proto);
	689	if (err) {
	690	pr_err("PPTP: can't register pppox_proto\n");
	691	goto out_unregister_sk_proto;
	692	}
	693
	694	return 0;
	695
	696	out_unregister_sk_proto:
	697	proto_unregister(&pptp_sk_proto);
	698	out_gre_del_protocol:
	699	gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
	700	out_mem_free:
	701	vfree(callid_sock);
	702
	703	return err;
	704	}
	705
	706	static void __exit pptp_exit_module(void)
	707	{
	708	unregister_pppox_proto(PX_PROTO_PPTP);
	709	proto_unregister(&pptp_sk_proto);
	710	gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
	711	vfree(callid_sock);
	712	}
	713
	714	module_init(pptp_init_module);
	715	module_exit(pptp_exit_module);
	716
	717	MODULE_DESCRIPTION("Point-to-Point Tunneling Protocol");
	718	MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)");
	719	MODULE_LICENSE("GPL");