]> git.karo-electronics.de Git - mv-sheeva.git/blobdiff - drivers/net/pptp.c
Merge branch 'master' into tk71
[mv-sheeva.git] / drivers / net / pptp.c
diff --git a/drivers/net/pptp.c b/drivers/net/pptp.c
new file mode 100644 (file)
index 0000000..164cfad
--- /dev/null
@@ -0,0 +1,725 @@
+/*
+ *  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/if_ppp.h>
+#include <linux/notifier.h>
+#include <linux/file.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/version.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 **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;
+       u16 protocol;
+       u16 payload_len;
+       u16 call_id;
+       u32 seq;
+       u32 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();
+       for (i = find_next_bit(callid_bitmap, MAX_CALLID, 1); i < MAX_CALLID;
+            i = find_next_bit(callid_bitmap, MAX_CALLID, i + 1)) {
+               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_assign_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);
+       int err = 0;
+       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;
+
+       {
+               struct flowi fl = { .oif = 0,
+                       .nl_u = {
+                               .ip4_u = {
+                                       .daddr = opt->dst_addr.sin_addr.s_addr,
+                                       .saddr = opt->src_addr.sin_addr.s_addr,
+                                       .tos = RT_TOS(0) } },
+                       .proto = IPPROTO_GRE };
+               err = ip_route_output_key(&init_net, &rt, &fl);
+               if (err)
+                       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);
+               kfree_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    = rt->rt_dst;
+       iph->saddr    = rt->rt_src;
+       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(iph, &rt->dst, NULL);
+       ip_send_check(iph);
+
+       ip_local_out(skb);
+
+tx_error:
+       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);
+
+       /* test if acknowledgement present */
+       if (PPTP_GRE_IS_A(header->ver)) {
+               __u32 ack = (PPTP_GRE_IS_S(header->flags)) ?
+                               header->ack : header->seq; /* ack in different place if S = 0 */
+
+               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;
+       }
+
+       /* test if payload present */
+       if (!PPTP_GRE_IS_S(header->flags))
+               goto drop;
+
+       headersize  = sizeof(*header);
+       payload_len = ntohs(header->payload_len);
+       seq         = ntohl(header->seq);
+
+       /* no ack present? */
+       if (!PPTP_GRE_IS_A(header->ver))
+               headersize -= sizeof(header->ack);
+       /* check for incomplete packet (length smaller than expected) */
+       if (skb->len - 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)) {
+               release_sock(sk);
+               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;
+       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;
+
+       {
+               struct flowi fl = {
+                       .nl_u = {
+                               .ip4_u = {
+                                       .daddr = opt->dst_addr.sin_addr.s_addr,
+                                       .saddr = opt->src_addr.sin_addr.s_addr,
+                                       .tos = RT_CONN_FLAGS(sk) } },
+                       .proto = IPPROTO_GRE };
+               security_sk_classify_flow(sk, &fl);
+               if (ip_route_output_key(&init_net, &rt, &fl)) {
+                       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_MTU;
+       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;
+
+       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 error = -ENOMEM;
+       struct sock *sk;
+       struct pppox_sock *po;
+       struct pptp_opt *opt;
+
+       sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pptp_sk_proto);
+       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 = 0;
+       opt->ack_recv = 0; opt->ack_sent = 0;
+
+       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) {
+               pr_err("PPTP: cann't allocate memory\n");
+               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");