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> 26 #include <linux/ppp-ioctl.h> 27 #include <linux/notifier.h> 28 #include <linux/file.h> 29 #include <linux/in.h> 30 #include <linux/ip.h> 31 #include <linux/netfilter.h> 32 #include <linux/netfilter_ipv4.h> 33 #include <linux/rcupdate.h> 34 #include <linux/spinlock.h> 35 36 #include <net/sock.h> 37 #include <net/protocol.h> 38 #include <net/ip.h> 39 #include <net/icmp.h> 40 #include <net/route.h> 41 #include <net/gre.h> 42 43 #include <linux/uaccess.h> 44 45 #define PPTP_DRIVER_VERSION "0.8.5" 46 47 #define MAX_CALLID 65535 48 49 static DECLARE_BITMAP(callid_bitmap, MAX_CALLID + 1); 50 static struct pppox_sock **callid_sock; 51 52 static DEFINE_SPINLOCK(chan_lock); 53 54 static struct proto pptp_sk_proto __read_mostly; 55 static const struct ppp_channel_ops pptp_chan_ops; 56 static const struct proto_ops pptp_ops; 57 58 #define PPP_LCP_ECHOREQ 0x09 59 #define PPP_LCP_ECHOREP 0x0A 60 #define SC_RCV_BITS (SC_RCV_B7_1|SC_RCV_B7_0|SC_RCV_ODDP|SC_RCV_EVNP) 61 62 #define MISSING_WINDOW 20 63 #define WRAPPED(curseq, lastseq)\ 64 ((((curseq) & 0xffffff00) == 0) &&\ 65 (((lastseq) & 0xffffff00) == 0xffffff00)) 66 67 #define PPTP_GRE_PROTO 0x880B 68 #define PPTP_GRE_VER 0x1 69 70 #define PPTP_GRE_FLAG_C 0x80 71 #define PPTP_GRE_FLAG_R 0x40 72 #define PPTP_GRE_FLAG_K 0x20 73 #define PPTP_GRE_FLAG_S 0x10 74 #define PPTP_GRE_FLAG_A 0x80 75 76 #define PPTP_GRE_IS_C(f) ((f)&PPTP_GRE_FLAG_C) 77 #define PPTP_GRE_IS_R(f) ((f)&PPTP_GRE_FLAG_R) 78 #define PPTP_GRE_IS_K(f) ((f)&PPTP_GRE_FLAG_K) 79 #define PPTP_GRE_IS_S(f) ((f)&PPTP_GRE_FLAG_S) 80 #define PPTP_GRE_IS_A(f) ((f)&PPTP_GRE_FLAG_A) 81 82 #define PPTP_HEADER_OVERHEAD (2+sizeof(struct pptp_gre_header)) 83 struct pptp_gre_header { 84 u8 flags; 85 u8 ver; 86 u16 protocol; 87 u16 payload_len; 88 u16 call_id; 89 u32 seq; 90 u32 ack; 91 } __packed; 92 93 static struct pppox_sock *lookup_chan(u16 call_id, __be32 s_addr) 94 { 95 struct pppox_sock *sock; 96 struct pptp_opt *opt; 97 98 rcu_read_lock(); 99 sock = rcu_dereference(callid_sock[call_id]); 100 if (sock) { 101 opt = &sock->proto.pptp; 102 if (opt->dst_addr.sin_addr.s_addr != s_addr) 103 sock = NULL; 104 else 105 sock_hold(sk_pppox(sock)); 106 } 107 rcu_read_unlock(); 108 109 return sock; 110 } 111 112 static int lookup_chan_dst(u16 call_id, __be32 d_addr) 113 { 114 struct pppox_sock *sock; 115 struct pptp_opt *opt; 116 int i; 117 118 rcu_read_lock(); 119 i = 1; 120 for_each_set_bit_from(i, callid_bitmap, MAX_CALLID) { 121 sock = rcu_dereference(callid_sock[i]); 122 if (!sock) 123 continue; 124 opt = &sock->proto.pptp; 125 if (opt->dst_addr.call_id == call_id && 126 opt->dst_addr.sin_addr.s_addr == d_addr) 127 break; 128 } 129 rcu_read_unlock(); 130 131 return i < MAX_CALLID; 132 } 133 134 static int add_chan(struct pppox_sock *sock) 135 { 136 static int call_id; 137 138 spin_lock(&chan_lock); 139 if (!sock->proto.pptp.src_addr.call_id) { 140 call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, call_id + 1); 141 if (call_id == MAX_CALLID) { 142 call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, 1); 143 if (call_id == MAX_CALLID) 144 goto out_err; 145 } 146 sock->proto.pptp.src_addr.call_id = call_id; 147 } else if (test_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap)) 148 goto out_err; 149 150 set_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap); 151 rcu_assign_pointer(callid_sock[sock->proto.pptp.src_addr.call_id], sock); 152 spin_unlock(&chan_lock); 153 154 return 0; 155 156 out_err: 157 spin_unlock(&chan_lock); 158 return -1; 159 } 160 161 static void del_chan(struct pppox_sock *sock) 162 { 163 spin_lock(&chan_lock); 164 clear_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap); 165 RCU_INIT_POINTER(callid_sock[sock->proto.pptp.src_addr.call_id], NULL); 166 spin_unlock(&chan_lock); 167 synchronize_rcu(); 168 } 169 170 static int pptp_xmit(struct ppp_channel *chan, struct sk_buff *skb) 171 { 172 struct sock *sk = (struct sock *) chan->private; 173 struct pppox_sock *po = pppox_sk(sk); 174 struct pptp_opt *opt = &po->proto.pptp; 175 struct pptp_gre_header *hdr; 176 unsigned int header_len = sizeof(*hdr); 177 struct flowi4 fl4; 178 int islcp; 179 int len; 180 unsigned char *data; 181 __u32 seq_recv; 182 183 184 struct rtable *rt; 185 struct net_device *tdev; 186 struct iphdr *iph; 187 int max_headroom; 188 189 if (sk_pppox(po)->sk_state & PPPOX_DEAD) 190 goto tx_error; 191 192 rt = ip_route_output_ports(sock_net(sk), &fl4, NULL, 193 opt->dst_addr.sin_addr.s_addr, 194 opt->src_addr.sin_addr.s_addr, 195 0, 0, IPPROTO_GRE, 196 RT_TOS(0), 0); 197 if (IS_ERR(rt)) 198 goto tx_error; 199 200 tdev = rt->dst.dev; 201 202 max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(*iph) + sizeof(*hdr) + 2; 203 204 if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) { 205 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom); 206 if (!new_skb) { 207 ip_rt_put(rt); 208 goto tx_error; 209 } 210 if (skb->sk) 211 skb_set_owner_w(new_skb, skb->sk); 212 consume_skb(skb); 213 skb = new_skb; 214 } 215 216 data = skb->data; 217 islcp = ((data[0] << 8) + data[1]) == PPP_LCP && 1 <= data[2] && data[2] <= 7; 218 219 /* compress protocol field */ 220 if ((opt->ppp_flags & SC_COMP_PROT) && data[0] == 0 && !islcp) 221 skb_pull(skb, 1); 222 223 /* Put in the address/control bytes if necessary */ 224 if ((opt->ppp_flags & SC_COMP_AC) == 0 || islcp) { 225 data = skb_push(skb, 2); 226 data[0] = PPP_ALLSTATIONS; 227 data[1] = PPP_UI; 228 } 229 230 len = skb->len; 231 232 seq_recv = opt->seq_recv; 233 234 if (opt->ack_sent == seq_recv) 235 header_len -= sizeof(hdr->ack); 236 237 /* Push down and install GRE header */ 238 skb_push(skb, header_len); 239 hdr = (struct pptp_gre_header *)(skb->data); 240 241 hdr->flags = PPTP_GRE_FLAG_K; 242 hdr->ver = PPTP_GRE_VER; 243 hdr->protocol = htons(PPTP_GRE_PROTO); 244 hdr->call_id = htons(opt->dst_addr.call_id); 245 246 hdr->flags |= PPTP_GRE_FLAG_S; 247 hdr->seq = htonl(++opt->seq_sent); 248 if (opt->ack_sent != seq_recv) { 249 /* send ack with this message */ 250 hdr->ver |= PPTP_GRE_FLAG_A; 251 hdr->ack = htonl(seq_recv); 252 opt->ack_sent = seq_recv; 253 } 254 hdr->payload_len = htons(len); 255 256 /* Push down and install the IP header. */ 257 258 skb_reset_transport_header(skb); 259 skb_push(skb, sizeof(*iph)); 260 skb_reset_network_header(skb); 261 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); 262 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | IPSKB_REROUTED); 263 264 iph = ip_hdr(skb); 265 iph->version = 4; 266 iph->ihl = sizeof(struct iphdr) >> 2; 267 if (ip_dont_fragment(sk, &rt->dst)) 268 iph->frag_off = htons(IP_DF); 269 else 270 iph->frag_off = 0; 271 iph->protocol = IPPROTO_GRE; 272 iph->tos = 0; 273 iph->daddr = fl4.daddr; 274 iph->saddr = fl4.saddr; 275 iph->ttl = ip4_dst_hoplimit(&rt->dst); 276 iph->tot_len = htons(skb->len); 277 278 skb_dst_drop(skb); 279 skb_dst_set(skb, &rt->dst); 280 281 nf_reset(skb); 282 283 skb->ip_summed = CHECKSUM_NONE; 284 ip_select_ident(iph, &rt->dst, NULL); 285 ip_send_check(iph); 286 287 ip_local_out(skb); 288 return 1; 289 290 tx_error: 291 kfree_skb(skb); 292 return 1; 293 } 294 295 static int pptp_rcv_core(struct sock *sk, struct sk_buff *skb) 296 { 297 struct pppox_sock *po = pppox_sk(sk); 298 struct pptp_opt *opt = &po->proto.pptp; 299 int headersize, payload_len, seq; 300 __u8 *payload; 301 struct pptp_gre_header *header; 302 303 if (!(sk->sk_state & PPPOX_CONNECTED)) { 304 if (sock_queue_rcv_skb(sk, skb)) 305 goto drop; 306 return NET_RX_SUCCESS; 307 } 308 309 header = (struct pptp_gre_header *)(skb->data); 310 headersize = sizeof(*header); 311 312 /* test if acknowledgement present */ 313 if (PPTP_GRE_IS_A(header->ver)) { 314 __u32 ack; 315 316 if (!pskb_may_pull(skb, headersize)) 317 goto drop; 318 header = (struct pptp_gre_header *)(skb->data); 319 320 /* ack in different place if S = 0 */ 321 ack = PPTP_GRE_IS_S(header->flags) ? header->ack : header->seq; 322 323 ack = ntohl(ack); 324 325 if (ack > opt->ack_recv) 326 opt->ack_recv = ack; 327 /* also handle sequence number wrap-around */ 328 if (WRAPPED(ack, opt->ack_recv)) 329 opt->ack_recv = ack; 330 } else { 331 headersize -= sizeof(header->ack); 332 } 333 /* test if payload present */ 334 if (!PPTP_GRE_IS_S(header->flags)) 335 goto drop; 336 337 payload_len = ntohs(header->payload_len); 338 seq = ntohl(header->seq); 339 340 /* check for incomplete packet (length smaller than expected) */ 341 if (!pskb_may_pull(skb, headersize + payload_len)) 342 goto drop; 343 344 payload = skb->data + headersize; 345 /* check for expected sequence number */ 346 if (seq < opt->seq_recv + 1 || WRAPPED(opt->seq_recv, seq)) { 347 if ((payload[0] == PPP_ALLSTATIONS) && (payload[1] == PPP_UI) && 348 (PPP_PROTOCOL(payload) == PPP_LCP) && 349 ((payload[4] == PPP_LCP_ECHOREQ) || (payload[4] == PPP_LCP_ECHOREP))) 350 goto allow_packet; 351 } else { 352 opt->seq_recv = seq; 353 allow_packet: 354 skb_pull(skb, headersize); 355 356 if (payload[0] == PPP_ALLSTATIONS && payload[1] == PPP_UI) { 357 /* chop off address/control */ 358 if (skb->len < 3) 359 goto drop; 360 skb_pull(skb, 2); 361 } 362 363 if ((*skb->data) & 1) { 364 /* protocol is compressed */ 365 skb_push(skb, 1)[0] = 0; 366 } 367 368 skb->ip_summed = CHECKSUM_NONE; 369 skb_set_network_header(skb, skb->head-skb->data); 370 ppp_input(&po->chan, skb); 371 372 return NET_RX_SUCCESS; 373 } 374 drop: 375 kfree_skb(skb); 376 return NET_RX_DROP; 377 } 378 379 static int pptp_rcv(struct sk_buff *skb) 380 { 381 struct pppox_sock *po; 382 struct pptp_gre_header *header; 383 struct iphdr *iph; 384 385 if (skb->pkt_type != PACKET_HOST) 386 goto drop; 387 388 if (!pskb_may_pull(skb, 12)) 389 goto drop; 390 391 iph = ip_hdr(skb); 392 393 header = (struct pptp_gre_header *)skb->data; 394 395 if (ntohs(header->protocol) != PPTP_GRE_PROTO || /* PPTP-GRE protocol for PPTP */ 396 PPTP_GRE_IS_C(header->flags) || /* flag C should be clear */ 397 PPTP_GRE_IS_R(header->flags) || /* flag R should be clear */ 398 !PPTP_GRE_IS_K(header->flags) || /* flag K should be set */ 399 (header->flags&0xF) != 0) /* routing and recursion ctrl = 0 */ 400 /* if invalid, discard this packet */ 401 goto drop; 402 403 po = lookup_chan(htons(header->call_id), iph->saddr); 404 if (po) { 405 skb_dst_drop(skb); 406 nf_reset(skb); 407 return sk_receive_skb(sk_pppox(po), skb, 0); 408 } 409 drop: 410 kfree_skb(skb); 411 return NET_RX_DROP; 412 } 413 414 static int pptp_bind(struct socket *sock, struct sockaddr *uservaddr, 415 int sockaddr_len) 416 { 417 struct sock *sk = sock->sk; 418 struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr; 419 struct pppox_sock *po = pppox_sk(sk); 420 struct pptp_opt *opt = &po->proto.pptp; 421 int error = 0; 422 423 lock_sock(sk); 424 425 opt->src_addr = sp->sa_addr.pptp; 426 if (add_chan(po)) 427 error = -EBUSY; 428 429 release_sock(sk); 430 return error; 431 } 432 433 static int pptp_connect(struct socket *sock, struct sockaddr *uservaddr, 434 int sockaddr_len, int flags) 435 { 436 struct sock *sk = sock->sk; 437 struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr; 438 struct pppox_sock *po = pppox_sk(sk); 439 struct pptp_opt *opt = &po->proto.pptp; 440 struct rtable *rt; 441 struct flowi4 fl4; 442 int error = 0; 443 444 if (sp->sa_protocol != PX_PROTO_PPTP) 445 return -EINVAL; 446 447 if (lookup_chan_dst(sp->sa_addr.pptp.call_id, sp->sa_addr.pptp.sin_addr.s_addr)) 448 return -EALREADY; 449 450 lock_sock(sk); 451 /* Check for already bound sockets */ 452 if (sk->sk_state & PPPOX_CONNECTED) { 453 error = -EBUSY; 454 goto end; 455 } 456 457 /* Check for already disconnected sockets, on attempts to disconnect */ 458 if (sk->sk_state & PPPOX_DEAD) { 459 error = -EALREADY; 460 goto end; 461 } 462 463 if (!opt->src_addr.sin_addr.s_addr || !sp->sa_addr.pptp.sin_addr.s_addr) { 464 error = -EINVAL; 465 goto end; 466 } 467 468 po->chan.private = sk; 469 po->chan.ops = &pptp_chan_ops; 470 471 rt = ip_route_output_ports(sock_net(sk), &fl4, sk, 472 opt->dst_addr.sin_addr.s_addr, 473 opt->src_addr.sin_addr.s_addr, 474 0, 0, 475 IPPROTO_GRE, RT_CONN_FLAGS(sk), 0); 476 if (IS_ERR(rt)) { 477 error = -EHOSTUNREACH; 478 goto end; 479 } 480 sk_setup_caps(sk, &rt->dst); 481 482 po->chan.mtu = dst_mtu(&rt->dst); 483 if (!po->chan.mtu) 484 po->chan.mtu = PPP_MRU; 485 ip_rt_put(rt); 486 po->chan.mtu -= PPTP_HEADER_OVERHEAD; 487 488 po->chan.hdrlen = 2 + sizeof(struct pptp_gre_header); 489 error = ppp_register_channel(&po->chan); 490 if (error) { 491 pr_err("PPTP: failed to register PPP channel (%d)\n", error); 492 goto end; 493 } 494 495 opt->dst_addr = sp->sa_addr.pptp; 496 sk->sk_state = PPPOX_CONNECTED; 497 498 end: 499 release_sock(sk); 500 return error; 501 } 502 503 static int pptp_getname(struct socket *sock, struct sockaddr *uaddr, 504 int *usockaddr_len, int peer) 505 { 506 int len = sizeof(struct sockaddr_pppox); 507 struct sockaddr_pppox sp; 508 509 sp.sa_family = AF_PPPOX; 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 } 561 562 static int pptp_create(struct net *net, struct socket *sock) 563 { 564 int error = -ENOMEM; 565 struct sock *sk; 566 struct pppox_sock *po; 567 struct pptp_opt *opt; 568 569 sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pptp_sk_proto); 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; 587 588 opt->seq_sent = 0; opt->seq_recv = 0xffffffff; 589 opt->ack_recv = 0; opt->ack_sent = 0xffffffff; 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 } 626 627 static const struct ppp_channel_ops pptp_chan_ops = { 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 }; 657 658 static const struct pppox_proto pppox_pptp_proto = { 659 .create = pptp_create, 660 .owner = THIS_MODULE, 661 }; 662 663 static const struct gre_protocol gre_pptp_protocol = { 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"); 671 672 callid_sock = vzalloc((MAX_CALLID + 1) * sizeof(void *)); 673 if (!callid_sock) 674 return -ENOMEM; 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"); 720