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/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); 48 static struct pppox_sock __rcu **callid_sock; 49 50 static DEFINE_SPINLOCK(chan_lock); 51 52 static struct proto pptp_sk_proto __read_mostly; 53 static const struct ppp_channel_ops pptp_chan_ops; 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; 84 __be16 protocol; 85 __be16 payload_len; 86 __be16 call_id; 87 __be32 seq; 88 __be32 ack; 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(); 117 i = 1; 118 for_each_set_bit_from(i, callid_bitmap, MAX_CALLID) { 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); 163 RCU_INIT_POINTER(callid_sock[sock->proto.pptp.src_addr.call_id], NULL); 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 net *net = sock_net(sk); 173 struct pptp_opt *opt = &po->proto.pptp; 174 struct pptp_gre_header *hdr; 175 unsigned int header_len = sizeof(*hdr); 176 struct flowi4 fl4; 177 int islcp; 178 int len; 179 unsigned char *data; 180 __u32 seq_recv; 181 182 183 struct rtable *rt; 184 struct net_device *tdev; 185 struct iphdr *iph; 186 int max_headroom; 187 188 if (sk_pppox(po)->sk_state & PPPOX_DEAD) 189 goto tx_error; 190 191 rt = ip_route_output_ports(net, &fl4, NULL, 192 opt->dst_addr.sin_addr.s_addr, 193 opt->src_addr.sin_addr.s_addr, 194 0, 0, IPPROTO_GRE, 195 RT_TOS(0), 0); 196 if (IS_ERR(rt)) 197 goto tx_error; 198 199 tdev = rt->dst.dev; 200 201 max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(*iph) + sizeof(*hdr) + 2; 202 203 if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) { 204 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom); 205 if (!new_skb) { 206 ip_rt_put(rt); 207 goto tx_error; 208 } 209 if (skb->sk) 210 skb_set_owner_w(new_skb, skb->sk); 211 consume_skb(skb); 212 skb = new_skb; 213 } 214 215 data = skb->data; 216 islcp = ((data[0] << 8) + data[1]) == PPP_LCP && 1 <= data[2] && data[2] <= 7; 217 218 /* compress protocol field */ 219 if ((opt->ppp_flags & SC_COMP_PROT) && data[0] == 0 && !islcp) 220 skb_pull(skb, 1); 221 222 /* Put in the address/control bytes if necessary */ 223 if ((opt->ppp_flags & SC_COMP_AC) == 0 || islcp) { 224 data = skb_push(skb, 2); 225 data[0] = PPP_ALLSTATIONS; 226 data[1] = PPP_UI; 227 } 228 229 len = skb->len; 230 231 seq_recv = opt->seq_recv; 232 233 if (opt->ack_sent == seq_recv) 234 header_len -= sizeof(hdr->ack); 235 236 /* Push down and install GRE header */ 237 skb_push(skb, header_len); 238 hdr = (struct pptp_gre_header *)(skb->data); 239 240 hdr->flags = PPTP_GRE_FLAG_K; 241 hdr->ver = PPTP_GRE_VER; 242 hdr->protocol = htons(PPTP_GRE_PROTO); 243 hdr->call_id = htons(opt->dst_addr.call_id); 244 245 hdr->flags |= PPTP_GRE_FLAG_S; 246 hdr->seq = htonl(++opt->seq_sent); 247 if (opt->ack_sent != seq_recv) { 248 /* send ack with this message */ 249 hdr->ver |= PPTP_GRE_FLAG_A; 250 hdr->ack = htonl(seq_recv); 251 opt->ack_sent = seq_recv; 252 } 253 hdr->payload_len = htons(len); 254 255 /* Push down and install the IP header. */ 256 257 skb_reset_transport_header(skb); 258 skb_push(skb, sizeof(*iph)); 259 skb_reset_network_header(skb); 260 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); 261 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | IPSKB_REROUTED); 262 263 iph = ip_hdr(skb); 264 iph->version = 4; 265 iph->ihl = sizeof(struct iphdr) >> 2; 266 if (ip_dont_fragment(sk, &rt->dst)) 267 iph->frag_off = htons(IP_DF); 268 else 269 iph->frag_off = 0; 270 iph->protocol = IPPROTO_GRE; 271 iph->tos = 0; 272 iph->daddr = fl4.daddr; 273 iph->saddr = fl4.saddr; 274 iph->ttl = ip4_dst_hoplimit(&rt->dst); 275 iph->tot_len = htons(skb->len); 276 277 skb_dst_drop(skb); 278 skb_dst_set(skb, &rt->dst); 279 280 nf_reset(skb); 281 282 skb->ip_summed = CHECKSUM_NONE; 283 ip_select_ident(net, skb, NULL); 284 ip_send_check(iph); 285 286 ip_local_out(net, skb->sk, skb); 287 return 1; 288 289 tx_error: 290 kfree_skb(skb); 291 return 1; 292 } 293 294 static int pptp_rcv_core(struct sock *sk, struct sk_buff *skb) 295 { 296 struct pppox_sock *po = pppox_sk(sk); 297 struct pptp_opt *opt = &po->proto.pptp; 298 int headersize, payload_len, seq; 299 __u8 *payload; 300 struct pptp_gre_header *header; 301 302 if (!(sk->sk_state & PPPOX_CONNECTED)) { 303 if (sock_queue_rcv_skb(sk, skb)) 304 goto drop; 305 return NET_RX_SUCCESS; 306 } 307 308 header = (struct pptp_gre_header *)(skb->data); 309 headersize = sizeof(*header); 310 311 /* test if acknowledgement present */ 312 if (PPTP_GRE_IS_A(header->ver)) { 313 __u32 ack; 314 315 if (!pskb_may_pull(skb, headersize)) 316 goto drop; 317 header = (struct pptp_gre_header *)(skb->data); 318 319 /* ack in different place if S = 0 */ 320 ack = PPTP_GRE_IS_S(header->flags) ? header->ack : header->seq; 321 322 ack = ntohl(ack); 323 324 if (ack > opt->ack_recv) 325 opt->ack_recv = ack; 326 /* also handle sequence number wrap-around */ 327 if (WRAPPED(ack, opt->ack_recv)) 328 opt->ack_recv = ack; 329 } else { 330 headersize -= sizeof(header->ack); 331 } 332 /* test if payload present */ 333 if (!PPTP_GRE_IS_S(header->flags)) 334 goto drop; 335 336 payload_len = ntohs(header->payload_len); 337 seq = ntohl(header->seq); 338 339 /* check for incomplete packet (length smaller than expected) */ 340 if (!pskb_may_pull(skb, headersize + payload_len)) 341 goto drop; 342 343 payload = skb->data + headersize; 344 /* check for expected sequence number */ 345 if (seq < opt->seq_recv + 1 || WRAPPED(opt->seq_recv, seq)) { 346 if ((payload[0] == PPP_ALLSTATIONS) && (payload[1] == PPP_UI) && 347 (PPP_PROTOCOL(payload) == PPP_LCP) && 348 ((payload[4] == PPP_LCP_ECHOREQ) || (payload[4] == PPP_LCP_ECHOREP))) 349 goto allow_packet; 350 } else { 351 opt->seq_recv = seq; 352 allow_packet: 353 skb_pull(skb, headersize); 354 355 if (payload[0] == PPP_ALLSTATIONS && payload[1] == PPP_UI) { 356 /* chop off address/control */ 357 if (skb->len < 3) 358 goto drop; 359 skb_pull(skb, 2); 360 } 361 362 if ((*skb->data) & 1) { 363 /* protocol is compressed */ 364 skb_push(skb, 1)[0] = 0; 365 } 366 367 skb->ip_summed = CHECKSUM_NONE; 368 skb_set_network_header(skb, skb->head-skb->data); 369 ppp_input(&po->chan, skb); 370 371 return NET_RX_SUCCESS; 372 } 373 drop: 374 kfree_skb(skb); 375 return NET_RX_DROP; 376 } 377 378 static int pptp_rcv(struct sk_buff *skb) 379 { 380 struct pppox_sock *po; 381 struct pptp_gre_header *header; 382 struct iphdr *iph; 383 384 if (skb->pkt_type != PACKET_HOST) 385 goto drop; 386 387 if (!pskb_may_pull(skb, 12)) 388 goto drop; 389 390 iph = ip_hdr(skb); 391 392 header = (struct pptp_gre_header *)skb->data; 393 394 if (ntohs(header->protocol) != PPTP_GRE_PROTO || /* PPTP-GRE protocol for PPTP */ 395 PPTP_GRE_IS_C(header->flags) || /* flag C should be clear */ 396 PPTP_GRE_IS_R(header->flags) || /* flag R should be clear */ 397 !PPTP_GRE_IS_K(header->flags) || /* flag K should be set */ 398 (header->flags&0xF) != 0) /* routing and recursion ctrl = 0 */ 399 /* if invalid, discard this packet */ 400 goto drop; 401 402 po = lookup_chan(htons(header->call_id), iph->saddr); 403 if (po) { 404 skb_dst_drop(skb); 405 nf_reset(skb); 406 return sk_receive_skb(sk_pppox(po), skb, 0); 407 } 408 drop: 409 kfree_skb(skb); 410 return NET_RX_DROP; 411 } 412 413 static int pptp_bind(struct socket *sock, struct sockaddr *uservaddr, 414 int sockaddr_len) 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 int error = 0; 421 422 lock_sock(sk); 423 424 opt->src_addr = sp->sa_addr.pptp; 425 if (add_chan(po)) 426 error = -EBUSY; 427 428 release_sock(sk); 429 return error; 430 } 431 432 static int pptp_connect(struct socket *sock, struct sockaddr *uservaddr, 433 int sockaddr_len, int flags) 434 { 435 struct sock *sk = sock->sk; 436 struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr; 437 struct pppox_sock *po = pppox_sk(sk); 438 struct pptp_opt *opt = &po->proto.pptp; 439 struct rtable *rt; 440 struct flowi4 fl4; 441 int error = 0; 442 443 if (sp->sa_protocol != PX_PROTO_PPTP) 444 return -EINVAL; 445 446 if (lookup_chan_dst(sp->sa_addr.pptp.call_id, sp->sa_addr.pptp.sin_addr.s_addr)) 447 return -EALREADY; 448 449 lock_sock(sk); 450 /* Check for already bound sockets */ 451 if (sk->sk_state & PPPOX_CONNECTED) { 452 error = -EBUSY; 453 goto end; 454 } 455 456 /* Check for already disconnected sockets, on attempts to disconnect */ 457 if (sk->sk_state & PPPOX_DEAD) { 458 error = -EALREADY; 459 goto end; 460 } 461 462 if (!opt->src_addr.sin_addr.s_addr || !sp->sa_addr.pptp.sin_addr.s_addr) { 463 error = -EINVAL; 464 goto end; 465 } 466 467 po->chan.private = sk; 468 po->chan.ops = &pptp_chan_ops; 469 470 rt = ip_route_output_ports(sock_net(sk), &fl4, sk, 471 opt->dst_addr.sin_addr.s_addr, 472 opt->src_addr.sin_addr.s_addr, 473 0, 0, 474 IPPROTO_GRE, RT_CONN_FLAGS(sk), 0); 475 if (IS_ERR(rt)) { 476 error = -EHOSTUNREACH; 477 goto end; 478 } 479 sk_setup_caps(sk, &rt->dst); 480 481 po->chan.mtu = dst_mtu(&rt->dst); 482 if (!po->chan.mtu) 483 po->chan.mtu = PPP_MRU; 484 ip_rt_put(rt); 485 po->chan.mtu -= PPTP_HEADER_OVERHEAD; 486 487 po->chan.hdrlen = 2 + sizeof(struct pptp_gre_header); 488 error = ppp_register_channel(&po->chan); 489 if (error) { 490 pr_err("PPTP: failed to register PPP channel (%d)\n", error); 491 goto end; 492 } 493 494 opt->dst_addr = sp->sa_addr.pptp; 495 sk->sk_state = PPPOX_CONNECTED; 496 497 end: 498 release_sock(sk); 499 return error; 500 } 501 502 static int pptp_getname(struct socket *sock, struct sockaddr *uaddr, 503 int *usockaddr_len, int peer) 504 { 505 int len = sizeof(struct sockaddr_pppox); 506 struct sockaddr_pppox sp; 507 508 memset(&sp.sa_addr, 0, sizeof(sp.sa_addr)); 509 510 sp.sa_family = AF_PPPOX; 511 sp.sa_protocol = PX_PROTO_PPTP; 512 sp.sa_addr.pptp = pppox_sk(sock->sk)->proto.pptp.src_addr; 513 514 memcpy(uaddr, &sp, len); 515 516 *usockaddr_len = len; 517 518 return 0; 519 } 520 521 static int pptp_release(struct socket *sock) 522 { 523 struct sock *sk = sock->sk; 524 struct pppox_sock *po; 525 struct pptp_opt *opt; 526 int error = 0; 527 528 if (!sk) 529 return 0; 530 531 lock_sock(sk); 532 533 if (sock_flag(sk, SOCK_DEAD)) { 534 release_sock(sk); 535 return -EBADF; 536 } 537 538 po = pppox_sk(sk); 539 opt = &po->proto.pptp; 540 del_chan(po); 541 542 pppox_unbind_sock(sk); 543 sk->sk_state = PPPOX_DEAD; 544 545 sock_orphan(sk); 546 sock->sk = NULL; 547 548 release_sock(sk); 549 sock_put(sk); 550 551 return error; 552 } 553 554 static void pptp_sock_destruct(struct sock *sk) 555 { 556 if (!(sk->sk_state & PPPOX_DEAD)) { 557 del_chan(pppox_sk(sk)); 558 pppox_unbind_sock(sk); 559 } 560 skb_queue_purge(&sk->sk_receive_queue); 561 } 562 563 static int pptp_create(struct net *net, struct socket *sock, int kern) 564 { 565 int error = -ENOMEM; 566 struct sock *sk; 567 struct pppox_sock *po; 568 struct pptp_opt *opt; 569 570 sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pptp_sk_proto, kern); 571 if (!sk) 572 goto out; 573 574 sock_init_data(sock, sk); 575 576 sock->state = SS_UNCONNECTED; 577 sock->ops = &pptp_ops; 578 579 sk->sk_backlog_rcv = pptp_rcv_core; 580 sk->sk_state = PPPOX_NONE; 581 sk->sk_type = SOCK_STREAM; 582 sk->sk_family = PF_PPPOX; 583 sk->sk_protocol = PX_PROTO_PPTP; 584 sk->sk_destruct = pptp_sock_destruct; 585 586 po = pppox_sk(sk); 587 opt = &po->proto.pptp; 588 589 opt->seq_sent = 0; opt->seq_recv = 0xffffffff; 590 opt->ack_recv = 0; opt->ack_sent = 0xffffffff; 591 592 error = 0; 593 out: 594 return error; 595 } 596 597 static int pptp_ppp_ioctl(struct ppp_channel *chan, unsigned int cmd, 598 unsigned long arg) 599 { 600 struct sock *sk = (struct sock *) chan->private; 601 struct pppox_sock *po = pppox_sk(sk); 602 struct pptp_opt *opt = &po->proto.pptp; 603 void __user *argp = (void __user *)arg; 604 int __user *p = argp; 605 int err, val; 606 607 err = -EFAULT; 608 switch (cmd) { 609 case PPPIOCGFLAGS: 610 val = opt->ppp_flags; 611 if (put_user(val, p)) 612 break; 613 err = 0; 614 break; 615 case PPPIOCSFLAGS: 616 if (get_user(val, p)) 617 break; 618 opt->ppp_flags = val & ~SC_RCV_BITS; 619 err = 0; 620 break; 621 default: 622 err = -ENOTTY; 623 } 624 625 return err; 626 } 627 628 static const struct ppp_channel_ops pptp_chan_ops = { 629 .start_xmit = pptp_xmit, 630 .ioctl = pptp_ppp_ioctl, 631 }; 632 633 static struct proto pptp_sk_proto __read_mostly = { 634 .name = "PPTP", 635 .owner = THIS_MODULE, 636 .obj_size = sizeof(struct pppox_sock), 637 }; 638 639 static const struct proto_ops pptp_ops = { 640 .family = AF_PPPOX, 641 .owner = THIS_MODULE, 642 .release = pptp_release, 643 .bind = pptp_bind, 644 .connect = pptp_connect, 645 .socketpair = sock_no_socketpair, 646 .accept = sock_no_accept, 647 .getname = pptp_getname, 648 .poll = sock_no_poll, 649 .listen = sock_no_listen, 650 .shutdown = sock_no_shutdown, 651 .setsockopt = sock_no_setsockopt, 652 .getsockopt = sock_no_getsockopt, 653 .sendmsg = sock_no_sendmsg, 654 .recvmsg = sock_no_recvmsg, 655 .mmap = sock_no_mmap, 656 .ioctl = pppox_ioctl, 657 }; 658 659 static const struct pppox_proto pppox_pptp_proto = { 660 .create = pptp_create, 661 .owner = THIS_MODULE, 662 }; 663 664 static const struct gre_protocol gre_pptp_protocol = { 665 .handler = pptp_rcv, 666 }; 667 668 static int __init pptp_init_module(void) 669 { 670 int err = 0; 671 pr_info("PPTP driver version " PPTP_DRIVER_VERSION "\n"); 672 673 callid_sock = vzalloc((MAX_CALLID + 1) * sizeof(void *)); 674 if (!callid_sock) 675 return -ENOMEM; 676 677 err = gre_add_protocol(&gre_pptp_protocol, GREPROTO_PPTP); 678 if (err) { 679 pr_err("PPTP: can't add gre protocol\n"); 680 goto out_mem_free; 681 } 682 683 err = proto_register(&pptp_sk_proto, 0); 684 if (err) { 685 pr_err("PPTP: can't register sk_proto\n"); 686 goto out_gre_del_protocol; 687 } 688 689 err = register_pppox_proto(PX_PROTO_PPTP, &pppox_pptp_proto); 690 if (err) { 691 pr_err("PPTP: can't register pppox_proto\n"); 692 goto out_unregister_sk_proto; 693 } 694 695 return 0; 696 697 out_unregister_sk_proto: 698 proto_unregister(&pptp_sk_proto); 699 out_gre_del_protocol: 700 gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP); 701 out_mem_free: 702 vfree(callid_sock); 703 704 return err; 705 } 706 707 static void __exit pptp_exit_module(void) 708 { 709 unregister_pppox_proto(PX_PROTO_PPTP); 710 proto_unregister(&pptp_sk_proto); 711 gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP); 712 vfree(callid_sock); 713 } 714 715 module_init(pptp_init_module); 716 module_exit(pptp_exit_module); 717 718 MODULE_DESCRIPTION("Point-to-Point Tunneling Protocol"); 719 MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)"); 720 MODULE_LICENSE("GPL"); 721