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 struct pptp_addr *sa) 134 { 135 static int call_id; 136 137 spin_lock(&chan_lock); 138 if (!sa->call_id) { 139 call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, call_id + 1); 140 if (call_id == MAX_CALLID) { 141 call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, 1); 142 if (call_id == MAX_CALLID) 143 goto out_err; 144 } 145 sa->call_id = call_id; 146 } else if (test_bit(sa->call_id, callid_bitmap)) { 147 goto out_err; 148 } 149 150 sock->proto.pptp.src_addr = *sa; 151 set_bit(sa->call_id, callid_bitmap); 152 rcu_assign_pointer(callid_sock[sa->call_id], sock); 153 spin_unlock(&chan_lock); 154 155 return 0; 156 157 out_err: 158 spin_unlock(&chan_lock); 159 return -1; 160 } 161 162 static void del_chan(struct pppox_sock *sock) 163 { 164 spin_lock(&chan_lock); 165 clear_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap); 166 RCU_INIT_POINTER(callid_sock[sock->proto.pptp.src_addr.call_id], NULL); 167 spin_unlock(&chan_lock); 168 synchronize_rcu(); 169 } 170 171 static int pptp_xmit(struct ppp_channel *chan, struct sk_buff *skb) 172 { 173 struct sock *sk = (struct sock *) chan->private; 174 struct pppox_sock *po = pppox_sk(sk); 175 struct net *net = sock_net(sk); 176 struct pptp_opt *opt = &po->proto.pptp; 177 struct pptp_gre_header *hdr; 178 unsigned int header_len = sizeof(*hdr); 179 struct flowi4 fl4; 180 int islcp; 181 int len; 182 unsigned char *data; 183 __u32 seq_recv; 184 185 186 struct rtable *rt; 187 struct net_device *tdev; 188 struct iphdr *iph; 189 int max_headroom; 190 191 if (sk_pppox(po)->sk_state & PPPOX_DEAD) 192 goto tx_error; 193 194 rt = ip_route_output_ports(net, &fl4, NULL, 195 opt->dst_addr.sin_addr.s_addr, 196 opt->src_addr.sin_addr.s_addr, 197 0, 0, IPPROTO_GRE, 198 RT_TOS(0), 0); 199 if (IS_ERR(rt)) 200 goto tx_error; 201 202 tdev = rt->dst.dev; 203 204 max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(*iph) + sizeof(*hdr) + 2; 205 206 if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) { 207 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom); 208 if (!new_skb) { 209 ip_rt_put(rt); 210 goto tx_error; 211 } 212 if (skb->sk) 213 skb_set_owner_w(new_skb, skb->sk); 214 consume_skb(skb); 215 skb = new_skb; 216 } 217 218 data = skb->data; 219 islcp = ((data[0] << 8) + data[1]) == PPP_LCP && 1 <= data[2] && data[2] <= 7; 220 221 /* compress protocol field */ 222 if ((opt->ppp_flags & SC_COMP_PROT) && data[0] == 0 && !islcp) 223 skb_pull(skb, 1); 224 225 /* Put in the address/control bytes if necessary */ 226 if ((opt->ppp_flags & SC_COMP_AC) == 0 || islcp) { 227 data = skb_push(skb, 2); 228 data[0] = PPP_ALLSTATIONS; 229 data[1] = PPP_UI; 230 } 231 232 len = skb->len; 233 234 seq_recv = opt->seq_recv; 235 236 if (opt->ack_sent == seq_recv) 237 header_len -= sizeof(hdr->ack); 238 239 /* Push down and install GRE header */ 240 skb_push(skb, header_len); 241 hdr = (struct pptp_gre_header *)(skb->data); 242 243 hdr->flags = PPTP_GRE_FLAG_K; 244 hdr->ver = PPTP_GRE_VER; 245 hdr->protocol = htons(PPTP_GRE_PROTO); 246 hdr->call_id = htons(opt->dst_addr.call_id); 247 248 hdr->flags |= PPTP_GRE_FLAG_S; 249 hdr->seq = htonl(++opt->seq_sent); 250 if (opt->ack_sent != seq_recv) { 251 /* send ack with this message */ 252 hdr->ver |= PPTP_GRE_FLAG_A; 253 hdr->ack = htonl(seq_recv); 254 opt->ack_sent = seq_recv; 255 } 256 hdr->payload_len = htons(len); 257 258 /* Push down and install the IP header. */ 259 260 skb_reset_transport_header(skb); 261 skb_push(skb, sizeof(*iph)); 262 skb_reset_network_header(skb); 263 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); 264 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | IPSKB_REROUTED); 265 266 iph = ip_hdr(skb); 267 iph->version = 4; 268 iph->ihl = sizeof(struct iphdr) >> 2; 269 if (ip_dont_fragment(sk, &rt->dst)) 270 iph->frag_off = htons(IP_DF); 271 else 272 iph->frag_off = 0; 273 iph->protocol = IPPROTO_GRE; 274 iph->tos = 0; 275 iph->daddr = fl4.daddr; 276 iph->saddr = fl4.saddr; 277 iph->ttl = ip4_dst_hoplimit(&rt->dst); 278 iph->tot_len = htons(skb->len); 279 280 skb_dst_drop(skb); 281 skb_dst_set(skb, &rt->dst); 282 283 nf_reset(skb); 284 285 skb->ip_summed = CHECKSUM_NONE; 286 ip_select_ident(net, skb, NULL); 287 ip_send_check(iph); 288 289 ip_local_out(net, skb->sk, skb); 290 return 1; 291 292 tx_error: 293 kfree_skb(skb); 294 return 1; 295 } 296 297 static int pptp_rcv_core(struct sock *sk, struct sk_buff *skb) 298 { 299 struct pppox_sock *po = pppox_sk(sk); 300 struct pptp_opt *opt = &po->proto.pptp; 301 int headersize, payload_len, seq; 302 __u8 *payload; 303 struct pptp_gre_header *header; 304 305 if (!(sk->sk_state & PPPOX_CONNECTED)) { 306 if (sock_queue_rcv_skb(sk, skb)) 307 goto drop; 308 return NET_RX_SUCCESS; 309 } 310 311 header = (struct pptp_gre_header *)(skb->data); 312 headersize = sizeof(*header); 313 314 /* test if acknowledgement present */ 315 if (PPTP_GRE_IS_A(header->ver)) { 316 __u32 ack; 317 318 if (!pskb_may_pull(skb, headersize)) 319 goto drop; 320 header = (struct pptp_gre_header *)(skb->data); 321 322 /* ack in different place if S = 0 */ 323 ack = PPTP_GRE_IS_S(header->flags) ? header->ack : header->seq; 324 325 ack = ntohl(ack); 326 327 if (ack > opt->ack_recv) 328 opt->ack_recv = ack; 329 /* also handle sequence number wrap-around */ 330 if (WRAPPED(ack, opt->ack_recv)) 331 opt->ack_recv = ack; 332 } else { 333 headersize -= sizeof(header->ack); 334 } 335 /* test if payload present */ 336 if (!PPTP_GRE_IS_S(header->flags)) 337 goto drop; 338 339 payload_len = ntohs(header->payload_len); 340 seq = ntohl(header->seq); 341 342 /* check for incomplete packet (length smaller than expected) */ 343 if (!pskb_may_pull(skb, headersize + payload_len)) 344 goto drop; 345 346 payload = skb->data + headersize; 347 /* check for expected sequence number */ 348 if (seq < opt->seq_recv + 1 || WRAPPED(opt->seq_recv, seq)) { 349 if ((payload[0] == PPP_ALLSTATIONS) && (payload[1] == PPP_UI) && 350 (PPP_PROTOCOL(payload) == PPP_LCP) && 351 ((payload[4] == PPP_LCP_ECHOREQ) || (payload[4] == PPP_LCP_ECHOREP))) 352 goto allow_packet; 353 } else { 354 opt->seq_recv = seq; 355 allow_packet: 356 skb_pull(skb, headersize); 357 358 if (payload[0] == PPP_ALLSTATIONS && payload[1] == PPP_UI) { 359 /* chop off address/control */ 360 if (skb->len < 3) 361 goto drop; 362 skb_pull(skb, 2); 363 } 364 365 if ((*skb->data) & 1) { 366 /* protocol is compressed */ 367 skb_push(skb, 1)[0] = 0; 368 } 369 370 skb->ip_summed = CHECKSUM_NONE; 371 skb_set_network_header(skb, skb->head-skb->data); 372 ppp_input(&po->chan, skb); 373 374 return NET_RX_SUCCESS; 375 } 376 drop: 377 kfree_skb(skb); 378 return NET_RX_DROP; 379 } 380 381 static int pptp_rcv(struct sk_buff *skb) 382 { 383 struct pppox_sock *po; 384 struct pptp_gre_header *header; 385 struct iphdr *iph; 386 387 if (skb->pkt_type != PACKET_HOST) 388 goto drop; 389 390 if (!pskb_may_pull(skb, 12)) 391 goto drop; 392 393 iph = ip_hdr(skb); 394 395 header = (struct pptp_gre_header *)skb->data; 396 397 if (ntohs(header->protocol) != PPTP_GRE_PROTO || /* PPTP-GRE protocol for PPTP */ 398 PPTP_GRE_IS_C(header->flags) || /* flag C should be clear */ 399 PPTP_GRE_IS_R(header->flags) || /* flag R should be clear */ 400 !PPTP_GRE_IS_K(header->flags) || /* flag K should be set */ 401 (header->flags&0xF) != 0) /* routing and recursion ctrl = 0 */ 402 /* if invalid, discard this packet */ 403 goto drop; 404 405 po = lookup_chan(htons(header->call_id), iph->saddr); 406 if (po) { 407 skb_dst_drop(skb); 408 nf_reset(skb); 409 return sk_receive_skb(sk_pppox(po), skb, 0); 410 } 411 drop: 412 kfree_skb(skb); 413 return NET_RX_DROP; 414 } 415 416 static int pptp_bind(struct socket *sock, struct sockaddr *uservaddr, 417 int sockaddr_len) 418 { 419 struct sock *sk = sock->sk; 420 struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr; 421 struct pppox_sock *po = pppox_sk(sk); 422 int error = 0; 423 424 if (sockaddr_len < sizeof(struct sockaddr_pppox)) 425 return -EINVAL; 426 427 lock_sock(sk); 428 429 if (sk->sk_state & PPPOX_DEAD) { 430 error = -EALREADY; 431 goto out; 432 } 433 434 if (sk->sk_state & PPPOX_BOUND) { 435 error = -EBUSY; 436 goto out; 437 } 438 439 if (add_chan(po, &sp->sa_addr.pptp)) 440 error = -EBUSY; 441 else 442 sk->sk_state |= PPPOX_BOUND; 443 444 out: 445 release_sock(sk); 446 return error; 447 } 448 449 static int pptp_connect(struct socket *sock, struct sockaddr *uservaddr, 450 int sockaddr_len, int flags) 451 { 452 struct sock *sk = sock->sk; 453 struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr; 454 struct pppox_sock *po = pppox_sk(sk); 455 struct pptp_opt *opt = &po->proto.pptp; 456 struct rtable *rt; 457 struct flowi4 fl4; 458 int error = 0; 459 460 if (sockaddr_len < sizeof(struct sockaddr_pppox)) 461 return -EINVAL; 462 463 if (sp->sa_protocol != PX_PROTO_PPTP) 464 return -EINVAL; 465 466 if (lookup_chan_dst(sp->sa_addr.pptp.call_id, sp->sa_addr.pptp.sin_addr.s_addr)) 467 return -EALREADY; 468 469 lock_sock(sk); 470 /* Check for already bound sockets */ 471 if (sk->sk_state & PPPOX_CONNECTED) { 472 error = -EBUSY; 473 goto end; 474 } 475 476 /* Check for already disconnected sockets, on attempts to disconnect */ 477 if (sk->sk_state & PPPOX_DEAD) { 478 error = -EALREADY; 479 goto end; 480 } 481 482 if (!opt->src_addr.sin_addr.s_addr || !sp->sa_addr.pptp.sin_addr.s_addr) { 483 error = -EINVAL; 484 goto end; 485 } 486 487 po->chan.private = sk; 488 po->chan.ops = &pptp_chan_ops; 489 490 rt = ip_route_output_ports(sock_net(sk), &fl4, sk, 491 opt->dst_addr.sin_addr.s_addr, 492 opt->src_addr.sin_addr.s_addr, 493 0, 0, 494 IPPROTO_GRE, RT_CONN_FLAGS(sk), 0); 495 if (IS_ERR(rt)) { 496 error = -EHOSTUNREACH; 497 goto end; 498 } 499 sk_setup_caps(sk, &rt->dst); 500 501 po->chan.mtu = dst_mtu(&rt->dst); 502 if (!po->chan.mtu) 503 po->chan.mtu = PPP_MRU; 504 ip_rt_put(rt); 505 po->chan.mtu -= PPTP_HEADER_OVERHEAD; 506 507 po->chan.hdrlen = 2 + sizeof(struct pptp_gre_header); 508 error = ppp_register_channel(&po->chan); 509 if (error) { 510 pr_err("PPTP: failed to register PPP channel (%d)\n", error); 511 goto end; 512 } 513 514 opt->dst_addr = sp->sa_addr.pptp; 515 sk->sk_state |= PPPOX_CONNECTED; 516 517 end: 518 release_sock(sk); 519 return error; 520 } 521 522 static int pptp_getname(struct socket *sock, struct sockaddr *uaddr, 523 int *usockaddr_len, int peer) 524 { 525 int len = sizeof(struct sockaddr_pppox); 526 struct sockaddr_pppox sp; 527 528 memset(&sp.sa_addr, 0, sizeof(sp.sa_addr)); 529 530 sp.sa_family = AF_PPPOX; 531 sp.sa_protocol = PX_PROTO_PPTP; 532 sp.sa_addr.pptp = pppox_sk(sock->sk)->proto.pptp.src_addr; 533 534 memcpy(uaddr, &sp, len); 535 536 *usockaddr_len = len; 537 538 return 0; 539 } 540 541 static int pptp_release(struct socket *sock) 542 { 543 struct sock *sk = sock->sk; 544 struct pppox_sock *po; 545 struct pptp_opt *opt; 546 int error = 0; 547 548 if (!sk) 549 return 0; 550 551 lock_sock(sk); 552 553 if (sock_flag(sk, SOCK_DEAD)) { 554 release_sock(sk); 555 return -EBADF; 556 } 557 558 po = pppox_sk(sk); 559 opt = &po->proto.pptp; 560 del_chan(po); 561 562 pppox_unbind_sock(sk); 563 sk->sk_state = PPPOX_DEAD; 564 565 sock_orphan(sk); 566 sock->sk = NULL; 567 568 release_sock(sk); 569 sock_put(sk); 570 571 return error; 572 } 573 574 static void pptp_sock_destruct(struct sock *sk) 575 { 576 if (!(sk->sk_state & PPPOX_DEAD)) { 577 del_chan(pppox_sk(sk)); 578 pppox_unbind_sock(sk); 579 } 580 skb_queue_purge(&sk->sk_receive_queue); 581 } 582 583 static int pptp_create(struct net *net, struct socket *sock, int kern) 584 { 585 int error = -ENOMEM; 586 struct sock *sk; 587 struct pppox_sock *po; 588 struct pptp_opt *opt; 589 590 sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pptp_sk_proto, kern); 591 if (!sk) 592 goto out; 593 594 sock_init_data(sock, sk); 595 596 sock->state = SS_UNCONNECTED; 597 sock->ops = &pptp_ops; 598 599 sk->sk_backlog_rcv = pptp_rcv_core; 600 sk->sk_state = PPPOX_NONE; 601 sk->sk_type = SOCK_STREAM; 602 sk->sk_family = PF_PPPOX; 603 sk->sk_protocol = PX_PROTO_PPTP; 604 sk->sk_destruct = pptp_sock_destruct; 605 606 po = pppox_sk(sk); 607 opt = &po->proto.pptp; 608 609 opt->seq_sent = 0; opt->seq_recv = 0xffffffff; 610 opt->ack_recv = 0; opt->ack_sent = 0xffffffff; 611 612 error = 0; 613 out: 614 return error; 615 } 616 617 static int pptp_ppp_ioctl(struct ppp_channel *chan, unsigned int cmd, 618 unsigned long arg) 619 { 620 struct sock *sk = (struct sock *) chan->private; 621 struct pppox_sock *po = pppox_sk(sk); 622 struct pptp_opt *opt = &po->proto.pptp; 623 void __user *argp = (void __user *)arg; 624 int __user *p = argp; 625 int err, val; 626 627 err = -EFAULT; 628 switch (cmd) { 629 case PPPIOCGFLAGS: 630 val = opt->ppp_flags; 631 if (put_user(val, p)) 632 break; 633 err = 0; 634 break; 635 case PPPIOCSFLAGS: 636 if (get_user(val, p)) 637 break; 638 opt->ppp_flags = val & ~SC_RCV_BITS; 639 err = 0; 640 break; 641 default: 642 err = -ENOTTY; 643 } 644 645 return err; 646 } 647 648 static const struct ppp_channel_ops pptp_chan_ops = { 649 .start_xmit = pptp_xmit, 650 .ioctl = pptp_ppp_ioctl, 651 }; 652 653 static struct proto pptp_sk_proto __read_mostly = { 654 .name = "PPTP", 655 .owner = THIS_MODULE, 656 .obj_size = sizeof(struct pppox_sock), 657 }; 658 659 static const struct proto_ops pptp_ops = { 660 .family = AF_PPPOX, 661 .owner = THIS_MODULE, 662 .release = pptp_release, 663 .bind = pptp_bind, 664 .connect = pptp_connect, 665 .socketpair = sock_no_socketpair, 666 .accept = sock_no_accept, 667 .getname = pptp_getname, 668 .poll = sock_no_poll, 669 .listen = sock_no_listen, 670 .shutdown = sock_no_shutdown, 671 .setsockopt = sock_no_setsockopt, 672 .getsockopt = sock_no_getsockopt, 673 .sendmsg = sock_no_sendmsg, 674 .recvmsg = sock_no_recvmsg, 675 .mmap = sock_no_mmap, 676 .ioctl = pppox_ioctl, 677 }; 678 679 static const struct pppox_proto pppox_pptp_proto = { 680 .create = pptp_create, 681 .owner = THIS_MODULE, 682 }; 683 684 static const struct gre_protocol gre_pptp_protocol = { 685 .handler = pptp_rcv, 686 }; 687 688 static int __init pptp_init_module(void) 689 { 690 int err = 0; 691 pr_info("PPTP driver version " PPTP_DRIVER_VERSION "\n"); 692 693 callid_sock = vzalloc((MAX_CALLID + 1) * sizeof(void *)); 694 if (!callid_sock) 695 return -ENOMEM; 696 697 err = gre_add_protocol(&gre_pptp_protocol, GREPROTO_PPTP); 698 if (err) { 699 pr_err("PPTP: can't add gre protocol\n"); 700 goto out_mem_free; 701 } 702 703 err = proto_register(&pptp_sk_proto, 0); 704 if (err) { 705 pr_err("PPTP: can't register sk_proto\n"); 706 goto out_gre_del_protocol; 707 } 708 709 err = register_pppox_proto(PX_PROTO_PPTP, &pppox_pptp_proto); 710 if (err) { 711 pr_err("PPTP: can't register pppox_proto\n"); 712 goto out_unregister_sk_proto; 713 } 714 715 return 0; 716 717 out_unregister_sk_proto: 718 proto_unregister(&pptp_sk_proto); 719 out_gre_del_protocol: 720 gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP); 721 out_mem_free: 722 vfree(callid_sock); 723 724 return err; 725 } 726 727 static void __exit pptp_exit_module(void) 728 { 729 unregister_pppox_proto(PX_PROTO_PPTP); 730 proto_unregister(&pptp_sk_proto); 731 gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP); 732 vfree(callid_sock); 733 } 734 735 module_init(pptp_init_module); 736 module_exit(pptp_exit_module); 737 738 MODULE_DESCRIPTION("Point-to-Point Tunneling Protocol"); 739 MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)"); 740 MODULE_LICENSE("GPL"); 741 MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_PPTP); 742