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MFC: Make apps using '#define _POSIX_C_SOURCE' compile.
[dragonfly.git] / lib / libalias / alias_db.c
blob70d1dd175bfdb30eebb7c64b8792fd84cb639554
1 /* -*- mode: c; tab-width: 8; c-basic-indent: 4; -*- */
2
3 /*-
4 * Copyright (c) 2001 Charles Mott <cm@linktel.net>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD: src/lib/libalias/alias_db.c,v 1.21.2.14 2002/07/24 03:21:24 luigi Exp $
29 * $DragonFly: src/lib/libalias/alias_db.c,v 1.6 2007/11/05 08:58:35 sephe Exp $
30 */
31
32 /*
33 Alias_db.c encapsulates all data structures used for storing
34 packet aliasing data. Other parts of the aliasing software
35 access data through functions provided in this file.
36
37 Data storage is based on the notion of a "link", which is
38 established for ICMP echo/reply packets, UDP datagrams and
39 TCP stream connections. A link stores the original source
40 and destination addresses. For UDP and TCP, it also stores
41 source and destination port numbers, as well as an alias
42 port number. Links are also used to store information about
43 fragments.
44
45 There is a facility for sweeping through and deleting old
46 links as new packets are sent through. A simple timeout is
47 used for ICMP and UDP links. TCP links are left alone unless
48 there is an incomplete connection, in which case the link
49 can be deleted after a certain amount of time.
50
51
52 Initial version: August, 1996 (cjm)
53
54 Version 1.4: September 16, 1996 (cjm)
55 Facility for handling incoming links added.
56
57 Version 1.6: September 18, 1996 (cjm)
58 ICMP data handling simplified.
59
60 Version 1.7: January 9, 1997 (cjm)
61 Fragment handling simplified.
62 Saves pointers for unresolved fragments.
63 Permits links for unspecified remote ports
64 or unspecified remote addresses.
65 Fixed bug which did not properly zero port
66 table entries after a link was deleted.
67 Cleaned up some obsolete comments.
68
69 Version 1.8: January 14, 1997 (cjm)
70 Fixed data type error in StartPoint().
71 (This error did not exist prior to v1.7
72 and was discovered and fixed by Ari Suutari)
73
74 Version 1.9: February 1, 1997
75 Optionally, connections initiated from packet aliasing host
76 machine will will not have their port number aliased unless it
77 conflicts with an aliasing port already being used. (cjm)
78
79 All options earlier being #ifdef'ed are now available through
80 a new interface, SetPacketAliasMode(). This allows run time
81 control (which is now available in PPP+pktAlias through the
82 'alias' keyword). (ee)
83
84 Added ability to create an alias port without
85 either destination address or port specified.
86 port type = ALIAS_PORT_UNKNOWN_DEST_ALL (ee)
87
88 Removed K&R style function headers
89 and general cleanup. (ee)
90
91 Added packetAliasMode to replace compiler #defines's (ee)
92
93 Allocates sockets for partially specified
94 ports if ALIAS_USE_SOCKETS defined. (cjm)
95
96 Version 2.0: March, 1997
97 SetAliasAddress() will now clean up alias links
98 if the aliasing address is changed. (cjm)
99
100 PacketAliasPermanentLink() function added to support permanent
101 links. (J. Fortes suggested the need for this.)
102 Examples:
103
104 (192.168.0.1, port 23) <-> alias port 6002, unknown dest addr/port
105
106 (192.168.0.2, port 21) <-> alias port 3604, known dest addr
107 unknown dest port
108
109 These permanent links allow for incoming connections to
110 machines on the local network. They can be given with a
111 user-chosen amount of specificity, with increasing specificity
112 meaning more security. (cjm)
113
114 Quite a bit of rework to the basic engine. The portTable[]
115 array, which kept track of which ports were in use was replaced
116 by a table/linked list structure. (cjm)
117
118 SetExpire() function added. (cjm)
119
120 DeleteLink() no longer frees memory association with a pointer
121 to a fragment (this bug was first recognized by E. Eklund in
122 v1.9).
123
124 Version 2.1: May, 1997 (cjm)
125 Packet aliasing engine reworked so that it can handle
126 multiple external addresses rather than just a single
127 host address.
128
129 PacketAliasRedirectPort() and PacketAliasRedirectAddr()
130 added to the API. The first function is a more generalized
131 version of PacketAliasPermanentLink(). The second function
132 implements static network address translation.
133
134 Version 3.2: July, 2000 (salander and satoh)
135 Added FindNewPortGroup to get contiguous range of port values.
136
137 Added QueryUdpTcpIn and QueryUdpTcpOut to look for an aliasing
138 link but not actually add one.
139
140 Added FindRtspOut, which is closely derived from FindUdpTcpOut,
141 except that the alias port (from FindNewPortGroup) is provided
142 as input.
143
144 See HISTORY file for additional revisions.
145 */
146
147
148 /* System include files */
149 #include <sys/param.h>
150 #include <sys/queue.h>
151 #include <sys/socket.h>
152 #include <sys/time.h>
153
154 #include <errno.h>
155 #include <stdlib.h>
156 #include <stdio.h>
157 #include <unistd.h>
158
159 /* BSD network include files */
160 #include <netinet/in_systm.h>
161 #include <netinet/in.h>
162 #include <netinet/ip.h>
163 #include <netinet/tcp.h>
164 #include <arpa/inet.h>
165
166 #include "alias.h"
167 #include "alias_local.h"
168
169
170
171 /*
172 Constants (note: constants are also defined
173 near relevant functions or structs)
174 */
175
176 /* Sizes of input and output link tables */
177 #define LINK_TABLE_OUT_SIZE 101
178 #define LINK_TABLE_IN_SIZE 4001
179
180 /* Parameters used for cleanup of expired links */
181 #define ALIAS_CLEANUP_INTERVAL_SECS 60
182 #define ALIAS_CLEANUP_MAX_SPOKES 30
183
184 /* Timeouts (in seconds) for different link types */
185 #define ICMP_EXPIRE_TIME 60
186 #define UDP_EXPIRE_TIME 60
187 #define PROTO_EXPIRE_TIME 60
188 #define FRAGMENT_ID_EXPIRE_TIME 10
189 #define FRAGMENT_PTR_EXPIRE_TIME 30
190
191 /* TCP link expire time for different cases */
192 /* When the link has been used and closed - minimal grace time to
193 allow ACKs and potential re-connect in FTP (XXX - is this allowed?) */
194 #ifndef TCP_EXPIRE_DEAD
195 # define TCP_EXPIRE_DEAD 10
196 #endif
197
198 /* When the link has been used and closed on one side - the other side
199 is allowed to still send data */
200 #ifndef TCP_EXPIRE_SINGLEDEAD
201 # define TCP_EXPIRE_SINGLEDEAD 90
202 #endif
203
204 /* When the link isn't yet up */
205 #ifndef TCP_EXPIRE_INITIAL
206 # define TCP_EXPIRE_INITIAL 300
207 #endif
208
209 /* When the link is up */
210 #ifndef TCP_EXPIRE_CONNECTED
211 # define TCP_EXPIRE_CONNECTED 86400
212 #endif
213
214
215 /* Dummy port number codes used for FindLinkIn/Out() and AddLink().
216 These constants can be anything except zero, which indicates an
217 unknown port number. */
218
219 #define NO_DEST_PORT 1
220 #define NO_SRC_PORT 1
221
222
223
224 /* Data Structures
225
226 The fundamental data structure used in this program is
227 "struct alias_link". Whenever a TCP connection is made,
228 a UDP datagram is sent out, or an ICMP echo request is made,
229 a link record is made (if it has not already been created).
230 The link record is identified by the source address/port
231 and the destination address/port. In the case of an ICMP
232 echo request, the source port is treated as being equivalent
233 with the 16-bit ID number of the ICMP packet.
234
235 The link record also can store some auxiliary data. For
236 TCP connections that have had sequence and acknowledgment
237 modifications, data space is available to track these changes.
238 A state field is used to keep track in changes to the TCP
239 connection state. ID numbers of fragments can also be
240 stored in the auxiliary space. Pointers to unresolved
241 fragments can also be stored.
242
243 The link records support two independent chainings. Lookup
244 tables for input and out tables hold the initial pointers
245 the link chains. On input, the lookup table indexes on alias
246 port and link type. On output, the lookup table indexes on
247 source address, destination address, source port, destination
248 port and link type.
249 */
250
251 struct ack_data_record /* used to save changes to ACK/sequence numbers */
252 {
253 u_long ack_old;
254 u_long ack_new;
255 int delta;
256 int active;
257 };
258
259 struct tcp_state /* Information about TCP connection */
260 {
261 int in; /* State for outside -> inside */
262 int out; /* State for inside -> outside */
263 int index; /* Index to ACK data array */
264 int ack_modified; /* Indicates whether ACK and sequence numbers */
265 /* been modified */
266 };
267
268 #define N_LINK_TCP_DATA 3 /* Number of distinct ACK number changes
269 saved for a modified TCP stream */
270 struct tcp_dat
271 {
272 struct tcp_state state;
273 struct ack_data_record ack[N_LINK_TCP_DATA];
274 int fwhole; /* Which firewall record is used for this hole? */
275 };
276
277 struct server /* LSNAT server pool (circular list) */
278 {
279 struct in_addr addr;
280 u_short port;
281 struct server *next;
282 };
283
284 struct alias_link /* Main data structure */
285 {
286 struct in_addr src_addr; /* Address and port information */
287 struct in_addr dst_addr;
288 struct in_addr alias_addr;
289 struct in_addr proxy_addr;
290 u_short src_port;
291 u_short dst_port;
292 u_short alias_port;
293 u_short proxy_port;
294 struct server *server;
295
296 int link_type; /* Type of link: TCP, UDP, ICMP, proto, frag */
297
298 /* values for link_type */
299 #define LINK_ICMP IPPROTO_ICMP
300 #define LINK_UDP IPPROTO_UDP
301 #define LINK_TCP IPPROTO_TCP
302 #define LINK_FRAGMENT_ID (IPPROTO_MAX + 1)
303 #define LINK_FRAGMENT_PTR (IPPROTO_MAX + 2)
304 #define LINK_ADDR (IPPROTO_MAX + 3)
305 #define LINK_PPTP (IPPROTO_MAX + 4)
306
307 int flags; /* indicates special characteristics */
308
309 /* flag bits */
310 #define LINK_UNKNOWN_DEST_PORT 0x01
311 #define LINK_UNKNOWN_DEST_ADDR 0x02
312 #define LINK_PERMANENT 0x04
313 #define LINK_PARTIALLY_SPECIFIED 0x03 /* logical-or of first two bits */
314 #define LINK_UNFIREWALLED 0x08
315 #define LINK_LAST_LINE_CRLF_TERMED 0x10
316
317 int timestamp; /* Time link was last accessed */
318 int expire_time; /* Expire time for link */
319
320 int sockfd; /* socket descriptor */
321
322 LIST_ENTRY(alias_link) list_out; /* Linked list of pointers for */
323 LIST_ENTRY(alias_link) list_in; /* input and output lookup tables */
324
325 union /* Auxiliary data */
326 {
327 char *frag_ptr;
328 struct in_addr frag_addr;
329 struct tcp_dat *tcp;
330 } data;
331 };
332
333
334
335
336
337 /* Global Variables
338
339 The global variables listed here are only accessed from
340 within alias_db.c and so are prefixed with the static
341 designation.
342 */
343
344 int packetAliasMode; /* Mode flags */
345 /* - documented in alias.h */
346
347 static struct in_addr aliasAddress; /* Address written onto source */
348 /* field of IP packet. */
349
350 static struct in_addr targetAddress; /* IP address incoming packets */
351 /* are sent to if no aliasing */
352 /* link already exists */
353
354 static struct in_addr nullAddress; /* Used as a dummy parameter for */
355 /* some function calls */
356 static LIST_HEAD(, alias_link)
357 linkTableOut[LINK_TABLE_OUT_SIZE]; /* Lookup table of pointers to */
358 /* chains of link records. Each */
359 static LIST_HEAD(, alias_link) /* link record is doubly indexed */
360 linkTableIn[LINK_TABLE_IN_SIZE]; /* into input and output lookup */
361 /* tables. */
362
363 static int icmpLinkCount; /* Link statistics */
364 static int udpLinkCount;
365 static int tcpLinkCount;
366 static int pptpLinkCount;
367 static int protoLinkCount;
368 static int fragmentIdLinkCount;
369 static int fragmentPtrLinkCount;
370 static int sockCount;
371
372 static int cleanupIndex; /* Index to chain of link table */
373 /* being inspected for old links */
374
375 static int timeStamp; /* System time in seconds for */
376 /* current packet */
377
378 static int lastCleanupTime; /* Last time IncrementalCleanup() */
379 /* was called */
380
381 static int houseKeepingResidual; /* used by HouseKeeping() */
382
383 static int deleteAllLinks; /* If equal to zero, DeleteLink() */
384 /* will not remove permanent links */
385
386 static FILE *monitorFile; /* File descriptor for link */
387 /* statistics monitoring file */
388
389 static int newDefaultLink; /* Indicates if a new aliasing */
390 /* link has been created after a */
391 /* call to PacketAliasIn/Out(). */
392
393 #ifndef NO_FW_PUNCH
394 static int fireWallFD = -1; /* File descriptor to be able to */
395 /* control firewall. Opened by */
396 /* PacketAliasSetMode on first */
397 /* setting the PKT_ALIAS_PUNCH_FW */
398 /* flag. */
399 #endif
400
401
402
403
404
405
406
407 /* Internal utility routines (used only in alias_db.c)
408
409 Lookup table starting points:
410 StartPointIn() -- link table initial search point for
411 incoming packets
412 StartPointOut() -- link table initial search point for
413 outgoing packets
414
415 Miscellaneous:
416 SeqDiff() -- difference between two TCP sequences
417 ShowAliasStats() -- send alias statistics to a monitor file
418 */
419
420
421 /* Local prototypes */
422 static u_int StartPointIn(struct in_addr, u_short, int);
423
424 static u_int StartPointOut(struct in_addr, struct in_addr,
425 u_short, u_short, int);
426
427 static int SeqDiff(u_long, u_long);
428
429 static void ShowAliasStats(void);
430
431 #ifndef NO_FW_PUNCH
432 /* Firewall control */
433 static void InitPunchFW(void);
434 static void UninitPunchFW(void);
435 static void ClearFWHole(struct alias_link *link);
436 #endif
437
438 /* Log file control */
439 static void InitPacketAliasLog(void);
440 static void UninitPacketAliasLog(void);
441
442 static u_int
443 StartPointIn(struct in_addr alias_addr,
444 u_short alias_port,
445 int link_type)
446 {
447 u_int n;
448
449 n = alias_addr.s_addr;
450 if (link_type != LINK_PPTP)
451 n += alias_port;
452 n += link_type;
453 return(n % LINK_TABLE_IN_SIZE);
454 }
455
456
457 static u_int
458 StartPointOut(struct in_addr src_addr, struct in_addr dst_addr,
459 u_short src_port, u_short dst_port, int link_type)
460 {
461 u_int n;
462
463 n = src_addr.s_addr;
464 n += dst_addr.s_addr;
465 if (link_type != LINK_PPTP) {
466 n += src_port;
467 n += dst_port;
468 }
469 n += link_type;
470
471 return(n % LINK_TABLE_OUT_SIZE);
472 }
473
474
475 static int
476 SeqDiff(u_long x, u_long y)
477 {
478 /* Return the difference between two TCP sequence numbers */
479
480 /*
481 This function is encapsulated in case there are any unusual
482 arithmetic conditions that need to be considered.
483 */
484
485 return (ntohl(y) - ntohl(x));
486 }
487
488
489 static void
490 ShowAliasStats(void)
491 {
492 /* Used for debugging */
493
494 if (monitorFile)
495 {
496 fprintf(monitorFile, "icmp=%d, udp=%d, tcp=%d, pptp=%d, proto=%d, frag_id=%d frag_ptr=%d",
497 icmpLinkCount,
498 udpLinkCount,
499 tcpLinkCount,
500 pptpLinkCount,
501 protoLinkCount,
502 fragmentIdLinkCount,
503 fragmentPtrLinkCount);
504
505 fprintf(monitorFile, " / tot=%d (sock=%d)\n",
506 icmpLinkCount + udpLinkCount
507 + tcpLinkCount
508 + pptpLinkCount
509 + protoLinkCount
510 + fragmentIdLinkCount
511 + fragmentPtrLinkCount,
512 sockCount);
513
514 fflush(monitorFile);
515 }
516 }
517
518
519
520
521
522 /* Internal routines for finding, deleting and adding links
523
524 Port Allocation:
525 GetNewPort() -- find and reserve new alias port number
526 GetSocket() -- try to allocate a socket for a given port
527
528 Link creation and deletion:
529 CleanupAliasData() - remove all link chains from lookup table
530 IncrementalCleanup() - look for stale links in a single chain
531 DeleteLink() - remove link
532 AddLink() - add link
533 ReLink() - change link
534
535 Link search:
536 FindLinkOut() - find link for outgoing packets
537 FindLinkIn() - find link for incoming packets
538
539 Port search:
540 FindNewPortGroup() - find an available group of ports
541 */
542
543 /* Local prototypes */
544 static int GetNewPort(struct alias_link *, int);
545
546 static u_short GetSocket(u_short, int *, int);
547
548 static void CleanupAliasData(void);
549
550 static void IncrementalCleanup(void);
551
552 static void DeleteLink(struct alias_link *);
553
554 static struct alias_link *
555 AddLink(struct in_addr, struct in_addr, struct in_addr,
556 u_short, u_short, int, int);
557
558 static struct alias_link *
559 ReLink(struct alias_link *,
560 struct in_addr, struct in_addr, struct in_addr,
561 u_short, u_short, int, int);
562
563 static struct alias_link *
564 FindLinkOut(struct in_addr, struct in_addr, u_short, u_short, int, int);
565
566 static struct alias_link *
567 FindLinkIn(struct in_addr, struct in_addr, u_short, u_short, int, int);
568
569
570 #define ALIAS_PORT_BASE 0x08000
571 #define ALIAS_PORT_MASK 0x07fff
572 #define ALIAS_PORT_MASK_EVEN 0x07ffe
573 #define GET_NEW_PORT_MAX_ATTEMPTS 20
574
575 #define GET_ALIAS_PORT -1
576 #define GET_ALIAS_ID GET_ALIAS_PORT
577
578 #define FIND_EVEN_ALIAS_BASE 1
579
580 /* GetNewPort() allocates port numbers. Note that if a port number
581 is already in use, that does not mean that it cannot be used by
582 another link concurrently. This is because GetNewPort() looks for
583 unused triplets: (dest addr, dest port, alias port). */
584
585 static int
586 GetNewPort(struct alias_link *link, int alias_port_param)
587 {
588 int i;
589 int max_trials;
590 u_short port_sys;
591 u_short port_net;
592
593 /*
594 Description of alias_port_param for GetNewPort(). When
595 this parameter is zero or positive, it precisely specifies
596 the port number. GetNewPort() will return this number
597 without check that it is in use.
598
599 When this parameter is GET_ALIAS_PORT, it indicates to get a randomly
600 selected port number.
601 */
602
603 if (alias_port_param == GET_ALIAS_PORT)
604 {
605 /*
606 * The aliasing port is automatically selected
607 * by one of two methods below:
608 */
609 max_trials = GET_NEW_PORT_MAX_ATTEMPTS;
610
611 if (packetAliasMode & PKT_ALIAS_SAME_PORTS)
612 {
613 /*
614 * When the PKT_ALIAS_SAME_PORTS option is
615 * chosen, the first try will be the
616 * actual source port. If this is already
617 * in use, the remainder of the trials
618 * will be random.
619 */
620 port_net = link->src_port;
621 port_sys = ntohs(port_net);
622 }
623 else
624 {
625 /* First trial and all subsequent are random. */
626 port_sys = random() & ALIAS_PORT_MASK;
627 port_sys += ALIAS_PORT_BASE;
628 port_net = htons(port_sys);
629 }
630 }
631 else if (alias_port_param >= 0 && alias_port_param < 0x10000)
632 {
633 link->alias_port = (u_short) alias_port_param;
634 return(0);
635 }
636 else
637 {
638 #ifdef DEBUG
639 fprintf(stderr, "PacketAlias/GetNewPort(): ");
640 fprintf(stderr, "input parameter error\n");
641 #endif
642 return(-1);
643 }
644
645
646 /* Port number search */
647 for (i=0; i<max_trials; i++)
648 {
649 int go_ahead;
650 struct alias_link *search_result;
651
652 search_result = FindLinkIn(link->dst_addr, link->alias_addr,
653 link->dst_port, port_net,
654 link->link_type, 0);
655
656 if (search_result == NULL)
657 go_ahead = 1;
658 else if (!(link->flags & LINK_PARTIALLY_SPECIFIED)
659 && (search_result->flags & LINK_PARTIALLY_SPECIFIED))
660 go_ahead = 1;
661 else
662 go_ahead = 0;
663
664 if (go_ahead)
665 {
666 if ((packetAliasMode & PKT_ALIAS_USE_SOCKETS)
667 && (link->flags & LINK_PARTIALLY_SPECIFIED)
668 && ((link->link_type == LINK_TCP) ||
669 (link->link_type == LINK_UDP)))
670 {
671 if (GetSocket(port_net, &link->sockfd, link->link_type))
672 {
673 link->alias_port = port_net;
674 return(0);
675 }
676 }
677 else
678 {
679 link->alias_port = port_net;
680 return(0);
681 }
682 }
683
684 port_sys = random() & ALIAS_PORT_MASK;
685 port_sys += ALIAS_PORT_BASE;
686 port_net = htons(port_sys);
687 }
688
689 #ifdef DEBUG
690 fprintf(stderr, "PacketAlias/GetnewPort(): ");
691 fprintf(stderr, "could not find free port\n");
692 #endif
693
694 return(-1);
695 }
696
697
698 static u_short
699 GetSocket(u_short port_net, int *sockfd, int link_type)
700 {
701 int err;
702 int sock;
703 struct sockaddr_in sock_addr;
704
705 if (link_type == LINK_TCP)
706 sock = socket(AF_INET, SOCK_STREAM, 0);
707 else if (link_type == LINK_UDP)
708 sock = socket(AF_INET, SOCK_DGRAM, 0);
709 else
710 {
711 #ifdef DEBUG
712 fprintf(stderr, "PacketAlias/GetSocket(): ");
713 fprintf(stderr, "incorrect link type\n");
714 #endif
715 return(0);
716 }
717
718 if (sock < 0)
719 {
720 #ifdef DEBUG
721 fprintf(stderr, "PacketAlias/GetSocket(): ");
722 fprintf(stderr, "socket() error %d\n", *sockfd);
723 #endif
724 return(0);
725 }
726
727 sock_addr.sin_family = AF_INET;
728 sock_addr.sin_addr.s_addr = htonl(INADDR_ANY);
729 sock_addr.sin_port = port_net;
730
731 err = bind(sock,
732 (struct sockaddr *) &sock_addr,
733 sizeof(sock_addr));
734 if (err == 0)
735 {
736 sockCount++;
737 *sockfd = sock;
738 return(1);
739 }
740 else
741 {
742 close(sock);
743 return(0);
744 }
745 }
746
747
748 /* FindNewPortGroup() returns a base port number for an available
749 range of contiguous port numbers. Note that if a port number
750 is already in use, that does not mean that it cannot be used by
751 another link concurrently. This is because FindNewPortGroup()
752 looks for unused triplets: (dest addr, dest port, alias port). */
753
754 int
755 FindNewPortGroup(struct in_addr dst_addr,
756 struct in_addr alias_addr,
757 u_short src_port,
758 u_short dst_port,
759 u_short port_count,
760 u_char proto,
761 u_char align)
762 {
763 int i, j;
764 int max_trials;
765 u_short port_sys;
766 int link_type;
767
768 /*
769 * Get link_type from protocol
770 */
771
772 switch (proto)
773 {
774 case IPPROTO_UDP:
775 link_type = LINK_UDP;
776 break;
777 case IPPROTO_TCP:
778 link_type = LINK_TCP;
779 break;
780 default:
781 return (0);
782 break;
783 }
784
785 /*
786 * The aliasing port is automatically selected
787 * by one of two methods below:
788 */
789 max_trials = GET_NEW_PORT_MAX_ATTEMPTS;
790
791 if (packetAliasMode & PKT_ALIAS_SAME_PORTS) {
792 /*
793 * When the ALIAS_SAME_PORTS option is
794 * chosen, the first try will be the
795 * actual source port. If this is already
796 * in use, the remainder of the trials
797 * will be random.
798 */
799 port_sys = ntohs(src_port);
800
801 } else {
802
803 /* First trial and all subsequent are random. */
804 if (align == FIND_EVEN_ALIAS_BASE)
805 port_sys = random() & ALIAS_PORT_MASK_EVEN;
806 else
807 port_sys = random() & ALIAS_PORT_MASK;
808
809 port_sys += ALIAS_PORT_BASE;
810 }
811
812 /* Port number search */
813 for (i = 0; i < max_trials; i++) {
814
815 struct alias_link *search_result;
816
817 for (j = 0; j < port_count; j++)
818 if (0 != (search_result = FindLinkIn(dst_addr, alias_addr,
819 dst_port, htons(port_sys + j),
820 link_type, 0)))
821 break;
822
823 /* Found a good range, return base */
824 if (j == port_count)
825 return (htons(port_sys));
826
827 /* Find a new base to try */
828 if (align == FIND_EVEN_ALIAS_BASE)
829 port_sys = random() & ALIAS_PORT_MASK_EVEN;
830 else
831 port_sys = random() & ALIAS_PORT_MASK;
832
833 port_sys += ALIAS_PORT_BASE;
834 }
835
836 #ifdef DEBUG
837 fprintf(stderr, "PacketAlias/FindNewPortGroup(): ");
838 fprintf(stderr, "could not find free port(s)\n");
839 #endif
840
841 return(0);
842 }
843
844 static void
845 CleanupAliasData(void)
846 {
847 struct alias_link *link;
848 int i, icount;
849
850 icount = 0;
851 for (i=0; i<LINK_TABLE_OUT_SIZE; i++)
852 {
853 link = LIST_FIRST(&linkTableOut[i]);
854 while (link != NULL)
855 {
856 struct alias_link *link_next;
857 link_next = LIST_NEXT(link, list_out);
858 icount++;
859 DeleteLink(link);
860 link = link_next;
861 }
862 }
863
864 cleanupIndex =0;
865 }
866
867
868 static void
869 IncrementalCleanup(void)
870 {
871 int icount;
872 struct alias_link *link;
873
874 icount = 0;
875 link = LIST_FIRST(&linkTableOut[cleanupIndex++]);
876 while (link != NULL)
877 {
878 int idelta;
879 struct alias_link *link_next;
880
881 link_next = LIST_NEXT(link, list_out);
882 idelta = timeStamp - link->timestamp;
883 switch (link->link_type)
884 {
885 case LINK_TCP:
886 if (idelta > link->expire_time)
887 {
888 struct tcp_dat *tcp_aux;
889
890 tcp_aux = link->data.tcp;
891 if (tcp_aux->state.in != ALIAS_TCP_STATE_CONNECTED
892 || tcp_aux->state.out != ALIAS_TCP_STATE_CONNECTED)
893 {
894 DeleteLink(link);
895 icount++;
896 }
897 }
898 break;
899 default:
900 if (idelta > link->expire_time)
901 {
902 DeleteLink(link);
903 icount++;
904 }
905 break;
906 }
907 link = link_next;
908 }
909
910 if (cleanupIndex == LINK_TABLE_OUT_SIZE)
911 cleanupIndex = 0;
912 }
913
914 static void
915 DeleteLink(struct alias_link *link)
916 {
917
918 /* Don't do anything if the link is marked permanent */
919 if (deleteAllLinks == 0 && link->flags & LINK_PERMANENT)
920 return;
921
922 #ifndef NO_FW_PUNCH
923 /* Delete associated firewall hole, if any */
924 ClearFWHole(link);
925 #endif
926
927 /* Free memory allocated for LSNAT server pool */
928 if (link->server != NULL) {
929 struct server *head, *curr, *next;
930
931 head = curr = link->server;
932 do {
933 next = curr->next;
934 free(curr);
935 } while ((curr = next) != head);
936 }
937
938 /* Adjust output table pointers */
939 LIST_REMOVE(link, list_out);
940
941 /* Adjust input table pointers */
942 LIST_REMOVE(link, list_in);
943
944 /* Close socket, if one has been allocated */
945 if (link->sockfd != -1)
946 {
947 sockCount--;
948 close(link->sockfd);
949 }
950
951 /* Link-type dependent cleanup */
952 switch(link->link_type)
953 {
954 case LINK_ICMP:
955 icmpLinkCount--;
956 break;
957 case LINK_UDP:
958 udpLinkCount--;
959 break;
960 case LINK_TCP:
961 tcpLinkCount--;
962 free(link->data.tcp);
963 break;
964 case LINK_PPTP:
965 pptpLinkCount--;
966 break;
967 case LINK_FRAGMENT_ID:
968 fragmentIdLinkCount--;
969 break;
970 case LINK_FRAGMENT_PTR:
971 fragmentPtrLinkCount--;
972 if (link->data.frag_ptr != NULL)
973 free(link->data.frag_ptr);
974 break;
975 case LINK_ADDR:
976 break;
977 default:
978 protoLinkCount--;
979 break;
980 }
981
982 /* Free memory */
983 free(link);
984
985 /* Write statistics, if logging enabled */
986 if (packetAliasMode & PKT_ALIAS_LOG)
987 {
988 ShowAliasStats();
989 }
990 }
991
992
993 static struct alias_link *
994 AddLink(struct in_addr src_addr,
995 struct in_addr dst_addr,
996 struct in_addr alias_addr,
997 u_short src_port,
998 u_short dst_port,
999 int alias_port_param, /* if less than zero, alias */
1000 int link_type) /* port will be automatically */
1001 { /* chosen. If greater than */
1002 u_int start_point; /* zero, equal to alias port */
1003 struct alias_link *link;
1004
1005 link = malloc(sizeof(struct alias_link));
1006 if (link != NULL)
1007 {
1008 /* Basic initialization */
1009 link->src_addr = src_addr;
1010 link->dst_addr = dst_addr;
1011 link->alias_addr = alias_addr;
1012 link->proxy_addr.s_addr = INADDR_ANY;
1013 link->src_port = src_port;
1014 link->dst_port = dst_port;
1015 link->proxy_port = 0;
1016 link->server = NULL;
1017 link->link_type = link_type;
1018 link->sockfd = -1;
1019 link->flags = 0;
1020 link->timestamp = timeStamp;
1021
1022 /* Expiration time */
1023 switch (link_type)
1024 {
1025 case LINK_ICMP:
1026 link->expire_time = ICMP_EXPIRE_TIME;
1027 break;
1028 case LINK_UDP:
1029 link->expire_time = UDP_EXPIRE_TIME;
1030 break;
1031 case LINK_TCP:
1032 link->expire_time = TCP_EXPIRE_INITIAL;
1033 break;
1034 case LINK_PPTP:
1035 link->flags |= LINK_PERMANENT; /* no timeout. */
1036 break;
1037 case LINK_FRAGMENT_ID:
1038 link->expire_time = FRAGMENT_ID_EXPIRE_TIME;
1039 break;
1040 case LINK_FRAGMENT_PTR:
1041 link->expire_time = FRAGMENT_PTR_EXPIRE_TIME;
1042 break;
1043 case LINK_ADDR:
1044 break;
1045 default:
1046 link->expire_time = PROTO_EXPIRE_TIME;
1047 break;
1048 }
1049
1050 /* Determine alias flags */
1051 if (dst_addr.s_addr == INADDR_ANY)
1052 link->flags |= LINK_UNKNOWN_DEST_ADDR;
1053 if (dst_port == 0)
1054 link->flags |= LINK_UNKNOWN_DEST_PORT;
1055
1056 /* Determine alias port */
1057 if (GetNewPort(link, alias_port_param) != 0)
1058 {
1059 free(link);
1060 return(NULL);
1061 }
1062
1063 /* Link-type dependent initialization */
1064 switch(link_type)
1065 {
1066 struct tcp_dat *aux_tcp;
1067
1068 case LINK_ICMP:
1069 icmpLinkCount++;
1070 break;
1071 case LINK_UDP:
1072 udpLinkCount++;
1073 break;
1074 case LINK_TCP:
1075 aux_tcp = malloc(sizeof(struct tcp_dat));
1076 if (aux_tcp != NULL)
1077 {
1078 int i;
1079
1080 tcpLinkCount++;
1081 aux_tcp->state.in = ALIAS_TCP_STATE_NOT_CONNECTED;
1082 aux_tcp->state.out = ALIAS_TCP_STATE_NOT_CONNECTED;
1083 aux_tcp->state.index = 0;
1084 aux_tcp->state.ack_modified = 0;
1085 for (i=0; i<N_LINK_TCP_DATA; i++)
1086 aux_tcp->ack[i].active = 0;
1087 aux_tcp->fwhole = -1;
1088 link->data.tcp = aux_tcp;
1089 }
1090 else
1091 {
1092 #ifdef DEBUG
1093 fprintf(stderr, "PacketAlias/AddLink: ");
1094 fprintf(stderr, " cannot allocate auxiliary TCP data\n");
1095 #endif
1096 free(link);
1097 return (NULL);
1098 }
1099 break;
1100 case LINK_PPTP:
1101 pptpLinkCount++;
1102 break;
1103 case LINK_FRAGMENT_ID:
1104 fragmentIdLinkCount++;
1105 break;
1106 case LINK_FRAGMENT_PTR:
1107 fragmentPtrLinkCount++;
1108 break;
1109 case LINK_ADDR:
1110 break;
1111 default:
1112 protoLinkCount++;
1113 break;
1114 }
1115
1116 /* Set up pointers for output lookup table */
1117 start_point = StartPointOut(src_addr, dst_addr,
1118 src_port, dst_port, link_type);
1119 LIST_INSERT_HEAD(&linkTableOut[start_point], link, list_out);
1120
1121 /* Set up pointers for input lookup table */
1122 start_point = StartPointIn(alias_addr, link->alias_port, link_type);
1123 LIST_INSERT_HEAD(&linkTableIn[start_point], link, list_in);
1124 }
1125 else
1126 {
1127 #ifdef DEBUG
1128 fprintf(stderr, "PacketAlias/AddLink(): ");
1129 fprintf(stderr, "malloc() call failed.\n");
1130 #endif
1131 }
1132
1133 if (packetAliasMode & PKT_ALIAS_LOG)
1134 {
1135 ShowAliasStats();
1136 }
1137
1138 return(link);
1139 }
1140
1141 static struct alias_link *
1142 ReLink(struct alias_link *old_link,
1143 struct in_addr src_addr,
1144 struct in_addr dst_addr,
1145 struct in_addr alias_addr,
1146 u_short src_port,
1147 u_short dst_port,
1148 int alias_port_param, /* if less than zero, alias */
1149 int link_type) /* port will be automatically */
1150 { /* chosen. If greater than */
1151 struct alias_link *new_link; /* zero, equal to alias port */
1152
1153 new_link = AddLink(src_addr, dst_addr, alias_addr,
1154 src_port, dst_port, alias_port_param,
1155 link_type);
1156 #ifndef NO_FW_PUNCH
1157 if (new_link != NULL &&
1158 old_link->link_type == LINK_TCP &&
1159 old_link->data.tcp->fwhole > 0) {
1160 PunchFWHole(new_link);
1161 }
1162 #endif
1163 DeleteLink(old_link);
1164 return new_link;
1165 }
1166
1167 static struct alias_link *
1168 _FindLinkOut(struct in_addr src_addr,
1169 struct in_addr dst_addr,
1170 u_short src_port,
1171 u_short dst_port,
1172 int link_type,
1173 int replace_partial_links)
1174 {
1175 u_int i;
1176 struct alias_link *link;
1177
1178 i = StartPointOut(src_addr, dst_addr, src_port, dst_port, link_type);
1179 LIST_FOREACH(link, &linkTableOut[i], list_out)
1180 {
1181 if (link->src_addr.s_addr == src_addr.s_addr
1182 && link->server == NULL
1183 && link->dst_addr.s_addr == dst_addr.s_addr
1184 && link->dst_port == dst_port
1185 && link->src_port == src_port
1186 && link->link_type == link_type)
1187 {
1188 link->timestamp = timeStamp;
1189 break;
1190 }
1191 }
1192
1193 /* Search for partially specified links. */
1194 if (link == NULL && replace_partial_links)
1195 {
1196 if (dst_port != 0 && dst_addr.s_addr != INADDR_ANY)
1197 {
1198 link = _FindLinkOut(src_addr, dst_addr, src_port, 0,
1199 link_type, 0);
1200 if (link == NULL)
1201 link = _FindLinkOut(src_addr, nullAddress, src_port,
1202 dst_port, link_type, 0);
1203 }
1204 if (link == NULL &&
1205 (dst_port != 0 || dst_addr.s_addr != INADDR_ANY))
1206 {
1207 link = _FindLinkOut(src_addr, nullAddress, src_port, 0,
1208 link_type, 0);
1209 }
1210 if (link != NULL)
1211 {
1212 link = ReLink(link,
1213 src_addr, dst_addr, link->alias_addr,
1214 src_port, dst_port, link->alias_port,
1215 link_type);
1216 }
1217 }
1218
1219 return(link);
1220 }
1221
1222 static struct alias_link *
1223 FindLinkOut(struct in_addr src_addr,
1224 struct in_addr dst_addr,
1225 u_short src_port,
1226 u_short dst_port,
1227 int link_type,
1228 int replace_partial_links)
1229 {
1230 struct alias_link *link;
1231
1232 link = _FindLinkOut(src_addr, dst_addr, src_port, dst_port,
1233 link_type, replace_partial_links);
1234
1235 if (link == NULL)
1236 {
1237 /* The following allows permanent links to be
1238 specified as using the default source address
1239 (i.e. device interface address) without knowing
1240 in advance what that address is. */
1241 if (aliasAddress.s_addr != 0 &&
1242 src_addr.s_addr == aliasAddress.s_addr)
1243 {
1244 link = _FindLinkOut(nullAddress, dst_addr, src_port, dst_port,
1245 link_type, replace_partial_links);
1246 }
1247 }
1248
1249 return(link);
1250 }
1251
1252
1253 static struct alias_link *
1254 _FindLinkIn(struct in_addr dst_addr,
1255 struct in_addr alias_addr,
1256 u_short dst_port,
1257 u_short alias_port,
1258 int link_type,
1259 int replace_partial_links)
1260 {
1261 int flags_in;
1262 u_int start_point;
1263 struct alias_link *link;
1264 struct alias_link *link_fully_specified;
1265 struct alias_link *link_unknown_all;
1266 struct alias_link *link_unknown_dst_addr;
1267 struct alias_link *link_unknown_dst_port;
1268
1269 /* Initialize pointers */
1270 link_fully_specified = NULL;
1271 link_unknown_all = NULL;
1272 link_unknown_dst_addr = NULL;
1273 link_unknown_dst_port = NULL;
1274
1275 /* If either the dest addr or port is unknown, the search
1276 loop will have to know about this. */
1277
1278 flags_in = 0;
1279 if (dst_addr.s_addr == INADDR_ANY)
1280 flags_in |= LINK_UNKNOWN_DEST_ADDR;
1281 if (dst_port == 0)
1282 flags_in |= LINK_UNKNOWN_DEST_PORT;
1283
1284 /* Search loop */
1285 start_point = StartPointIn(alias_addr, alias_port, link_type);
1286 LIST_FOREACH(link, &linkTableIn[start_point], list_in)
1287 {
1288 int flags;
1289
1290 flags = flags_in | link->flags;
1291 if (!(flags & LINK_PARTIALLY_SPECIFIED))
1292 {
1293 if (link->alias_addr.s_addr == alias_addr.s_addr
1294 && link->alias_port == alias_port
1295 && link->dst_addr.s_addr == dst_addr.s_addr
1296 && link->dst_port == dst_port
1297 && link->link_type == link_type)
1298 {
1299 link_fully_specified = link;
1300 break;
1301 }
1302 }
1303 else if ((flags & LINK_UNKNOWN_DEST_ADDR)
1304 && (flags & LINK_UNKNOWN_DEST_PORT))
1305 {
1306 if (link->alias_addr.s_addr == alias_addr.s_addr
1307 && link->alias_port == alias_port
1308 && link->link_type == link_type)
1309 {
1310 if (link_unknown_all == NULL)
1311 link_unknown_all = link;
1312 }
1313 }
1314 else if (flags & LINK_UNKNOWN_DEST_ADDR)
1315 {
1316 if (link->alias_addr.s_addr == alias_addr.s_addr
1317 && link->alias_port == alias_port
1318 && link->link_type == link_type
1319 && link->dst_port == dst_port)
1320 {
1321 if (link_unknown_dst_addr == NULL)
1322 link_unknown_dst_addr = link;
1323 }
1324 }
1325 else if (flags & LINK_UNKNOWN_DEST_PORT)
1326 {
1327 if (link->alias_addr.s_addr == alias_addr.s_addr
1328 && link->alias_port == alias_port
1329 && link->link_type == link_type
1330 && link->dst_addr.s_addr == dst_addr.s_addr)
1331 {
1332 if (link_unknown_dst_port == NULL)
1333 link_unknown_dst_port = link;
1334 }
1335 }
1336 }
1337
1338
1339
1340 if (link_fully_specified != NULL)
1341 {
1342 link_fully_specified->timestamp = timeStamp;
1343 link = link_fully_specified;
1344 }
1345 else if (link_unknown_dst_port != NULL)
1346 link = link_unknown_dst_port;
1347 else if (link_unknown_dst_addr != NULL)
1348 link = link_unknown_dst_addr;
1349 else if (link_unknown_all != NULL)
1350 link = link_unknown_all;
1351 else
1352 return (NULL);
1353
1354 if (replace_partial_links &&
1355 (link->flags & LINK_PARTIALLY_SPECIFIED || link->server != NULL))
1356 {
1357 struct in_addr src_addr;
1358 u_short src_port;
1359
1360 if (link->server != NULL) { /* LSNAT link */
1361 src_addr = link->server->addr;
1362 src_port = link->server->port;
1363 link->server = link->server->next;
1364 } else {
1365 src_addr = link->src_addr;
1366 src_port = link->src_port;
1367 }
1368
1369 link = ReLink(link,
1370 src_addr, dst_addr, alias_addr,
1371 src_port, dst_port, alias_port,
1372 link_type);
1373 }
1374
1375 return (link);
1376 }
1377
1378 static struct alias_link *
1379 FindLinkIn(struct in_addr dst_addr,
1380 struct in_addr alias_addr,
1381 u_short dst_port,
1382 u_short alias_port,
1383 int link_type,
1384 int replace_partial_links)
1385 {
1386 struct alias_link *link;
1387
1388 link = _FindLinkIn(dst_addr, alias_addr, dst_port, alias_port,
1389 link_type, replace_partial_links);
1390
1391 if (link == NULL)
1392 {
1393 /* The following allows permanent links to be
1394 specified as using the default aliasing address
1395 (i.e. device interface address) without knowing
1396 in advance what that address is. */
1397 if (aliasAddress.s_addr != 0 &&
1398 alias_addr.s_addr == aliasAddress.s_addr)
1399 {
1400 link = _FindLinkIn(dst_addr, nullAddress, dst_port, alias_port,
1401 link_type, replace_partial_links);
1402 }
1403 }
1404
1405 return(link);
1406 }
1407
1408
1409
1410
1411 /* External routines for finding/adding links
1412
1413 -- "external" means outside alias_db.c, but within alias*.c --
1414
1415 FindIcmpIn(), FindIcmpOut()
1416 FindFragmentIn1(), FindFragmentIn2()
1417 AddFragmentPtrLink(), FindFragmentPtr()
1418 FindProtoIn(), FindProtoOut()
1419 FindUdpTcpIn(), FindUdpTcpOut()
1420 AddPptp(), FindPptpOutByCallId(), FindPptpInByCallId(),
1421 FindPptpOutByPeerCallId(), FindPptpInByPeerCallId()
1422 FindOriginalAddress(), FindAliasAddress()
1423
1424 (prototypes in alias_local.h)
1425 */
1426
1427
1428 struct alias_link *
1429 FindIcmpIn(struct in_addr dst_addr,
1430 struct in_addr alias_addr,
1431 u_short id_alias,
1432 int create)
1433 {
1434 struct alias_link *link;
1435
1436 link = FindLinkIn(dst_addr, alias_addr,
1437 NO_DEST_PORT, id_alias,
1438 LINK_ICMP, 0);
1439 if (link == NULL && create && !(packetAliasMode & PKT_ALIAS_DENY_INCOMING))
1440 {
1441 struct in_addr target_addr;
1442
1443 target_addr = FindOriginalAddress(alias_addr);
1444 link = AddLink(target_addr, dst_addr, alias_addr,
1445 id_alias, NO_DEST_PORT, id_alias,
1446 LINK_ICMP);
1447 }
1448
1449 return (link);
1450 }
1451
1452
1453 struct alias_link *
1454 FindIcmpOut(struct in_addr src_addr,
1455 struct in_addr dst_addr,
1456 u_short id,
1457 int create)
1458 {
1459 struct alias_link * link;
1460
1461 link = FindLinkOut(src_addr, dst_addr,
1462 id, NO_DEST_PORT,
1463 LINK_ICMP, 0);
1464 if (link == NULL && create)
1465 {
1466 struct in_addr alias_addr;
1467
1468 alias_addr = FindAliasAddress(src_addr);
1469 link = AddLink(src_addr, dst_addr, alias_addr,
1470 id, NO_DEST_PORT, GET_ALIAS_ID,
1471 LINK_ICMP);
1472 }
1473
1474 return(link);
1475 }
1476
1477
1478 struct alias_link *
1479 FindFragmentIn1(struct in_addr dst_addr,
1480 struct in_addr alias_addr,
1481 u_short ip_id)
1482 {
1483 struct alias_link *link;
1484
1485 link = FindLinkIn(dst_addr, alias_addr,
1486 NO_DEST_PORT, ip_id,
1487 LINK_FRAGMENT_ID, 0);
1488
1489 if (link == NULL)
1490 {
1491 link = AddLink(nullAddress, dst_addr, alias_addr,
1492 NO_SRC_PORT, NO_DEST_PORT, ip_id,
1493 LINK_FRAGMENT_ID);
1494 }
1495
1496 return(link);
1497 }
1498
1499
1500 struct alias_link *
1501 FindFragmentIn2(struct in_addr dst_addr, /* Doesn't add a link if one */
1502 struct in_addr alias_addr, /* is not found. */
1503 u_short ip_id)
1504 {
1505 return FindLinkIn(dst_addr, alias_addr,
1506 NO_DEST_PORT, ip_id,
1507 LINK_FRAGMENT_ID, 0);
1508 }
1509
1510
1511 struct alias_link *
1512 AddFragmentPtrLink(struct in_addr dst_addr,
1513 u_short ip_id)
1514 {
1515 return AddLink(nullAddress, dst_addr, nullAddress,
1516 NO_SRC_PORT, NO_DEST_PORT, ip_id,
1517 LINK_FRAGMENT_PTR);
1518 }
1519
1520
1521 struct alias_link *
1522 FindFragmentPtr(struct in_addr dst_addr,
1523 u_short ip_id)
1524 {
1525 return FindLinkIn(dst_addr, nullAddress,
1526 NO_DEST_PORT, ip_id,
1527 LINK_FRAGMENT_PTR, 0);
1528 }
1529
1530
1531 struct alias_link *
1532 FindProtoIn(struct in_addr dst_addr,
1533 struct in_addr alias_addr,
1534 u_char proto)
1535 {
1536 struct alias_link *link;
1537
1538 link = FindLinkIn(dst_addr, alias_addr,
1539 NO_DEST_PORT, 0,
1540 proto, 1);
1541
1542 if (link == NULL && !(packetAliasMode & PKT_ALIAS_DENY_INCOMING))
1543 {
1544 struct in_addr target_addr;
1545
1546 target_addr = FindOriginalAddress(alias_addr);
1547 link = AddLink(target_addr, dst_addr, alias_addr,
1548 NO_SRC_PORT, NO_DEST_PORT, 0,
1549 proto);
1550 }
1551
1552 return (link);
1553 }
1554
1555
1556 struct alias_link *
1557 FindProtoOut(struct in_addr src_addr,
1558 struct in_addr dst_addr,
1559 u_char proto)
1560 {
1561 struct alias_link *link;
1562
1563 link = FindLinkOut(src_addr, dst_addr,
1564 NO_SRC_PORT, NO_DEST_PORT,
1565 proto, 1);
1566
1567 if (link == NULL)
1568 {
1569 struct in_addr alias_addr;
1570
1571 alias_addr = FindAliasAddress(src_addr);
1572 link = AddLink(src_addr, dst_addr, alias_addr,
1573 NO_SRC_PORT, NO_DEST_PORT, 0,
1574 proto);
1575 }
1576
1577 return (link);
1578 }
1579
1580
1581 struct alias_link *
1582 FindUdpTcpIn(struct in_addr dst_addr,
1583 struct in_addr alias_addr,
1584 u_short dst_port,
1585 u_short alias_port,
1586 u_char proto,
1587 int create)
1588 {
1589 int link_type;
1590 struct alias_link *link;
1591
1592 switch (proto)
1593 {
1594 case IPPROTO_UDP:
1595 link_type = LINK_UDP;
1596 break;
1597 case IPPROTO_TCP:
1598 link_type = LINK_TCP;
1599 break;
1600 default:
1601 return NULL;
1602 break;
1603 }
1604
1605 link = FindLinkIn(dst_addr, alias_addr,
1606 dst_port, alias_port,
1607 link_type, create);
1608
1609 if (link == NULL && create && !(packetAliasMode & PKT_ALIAS_DENY_INCOMING))
1610 {
1611 struct in_addr target_addr;
1612
1613 target_addr = FindOriginalAddress(alias_addr);
1614 link = AddLink(target_addr, dst_addr, alias_addr,
1615 alias_port, dst_port, alias_port,
1616 link_type);
1617 }
1618
1619 return(link);
1620 }
1621
1622
1623 struct alias_link *
1624 FindUdpTcpOut(struct in_addr src_addr,
1625 struct in_addr dst_addr,
1626 u_short src_port,
1627 u_short dst_port,
1628 u_char proto,
1629 int create)
1630 {
1631 int link_type;
1632 struct alias_link *link;
1633
1634 switch (proto)
1635 {
1636 case IPPROTO_UDP:
1637 link_type = LINK_UDP;
1638 break;
1639 case IPPROTO_TCP:
1640 link_type = LINK_TCP;
1641 break;
1642 default:
1643 return NULL;
1644 break;
1645 }
1646
1647 link = FindLinkOut(src_addr, dst_addr, src_port, dst_port, link_type, create);
1648
1649 if (link == NULL && create)
1650 {
1651 struct in_addr alias_addr;
1652
1653 alias_addr = FindAliasAddress(src_addr);
1654 link = AddLink(src_addr, dst_addr, alias_addr,
1655 src_port, dst_port, GET_ALIAS_PORT,
1656 link_type);
1657 }
1658
1659 return(link);
1660 }
1661
1662
1663 struct alias_link *
1664 AddPptp(struct in_addr src_addr,
1665 struct in_addr dst_addr,
1666 struct in_addr alias_addr,
1667 u_int16_t src_call_id)
1668 {
1669 struct alias_link *link;
1670
1671 link = AddLink(src_addr, dst_addr, alias_addr,
1672 src_call_id, 0, GET_ALIAS_PORT,
1673 LINK_PPTP);
1674
1675 return (link);
1676 }
1677
1678
1679 struct alias_link *
1680 FindPptpOutByCallId(struct in_addr src_addr,
1681 struct in_addr dst_addr,
1682 u_int16_t src_call_id)
1683 {
1684 u_int i;
1685 struct alias_link *link;
1686
1687 i = StartPointOut(src_addr, dst_addr, 0, 0, LINK_PPTP);
1688 LIST_FOREACH(link, &linkTableOut[i], list_out)
1689 if (link->link_type == LINK_PPTP &&
1690 link->src_addr.s_addr == src_addr.s_addr &&
1691 link->dst_addr.s_addr == dst_addr.s_addr &&
1692 link->src_port == src_call_id)
1693 break;
1694
1695 return (link);
1696 }
1697
1698
1699 struct alias_link *
1700 FindPptpOutByPeerCallId(struct in_addr src_addr,
1701 struct in_addr dst_addr,
1702 u_int16_t dst_call_id)
1703 {
1704 u_int i;
1705 struct alias_link *link;
1706
1707 i = StartPointOut(src_addr, dst_addr, 0, 0, LINK_PPTP);
1708 LIST_FOREACH(link, &linkTableOut[i], list_out)
1709 if (link->link_type == LINK_PPTP &&
1710 link->src_addr.s_addr == src_addr.s_addr &&
1711 link->dst_addr.s_addr == dst_addr.s_addr &&
1712 link->dst_port == dst_call_id)
1713 break;
1714
1715 return (link);
1716 }
1717
1718
1719 struct alias_link *
1720 FindPptpInByCallId(struct in_addr dst_addr,
1721 struct in_addr alias_addr,
1722 u_int16_t dst_call_id)
1723 {
1724 u_int i;
1725 struct alias_link *link;
1726
1727 i = StartPointIn(alias_addr, 0, LINK_PPTP);
1728 LIST_FOREACH(link, &linkTableIn[i], list_in)
1729 if (link->link_type == LINK_PPTP &&
1730 link->dst_addr.s_addr == dst_addr.s_addr &&
1731 link->alias_addr.s_addr == alias_addr.s_addr &&
1732 link->dst_port == dst_call_id)
1733 break;
1734
1735 return (link);
1736 }
1737
1738
1739 struct alias_link *
1740 FindPptpInByPeerCallId(struct in_addr dst_addr,
1741 struct in_addr alias_addr,
1742 u_int16_t alias_call_id)
1743 {
1744 struct alias_link *link;
1745
1746 link = FindLinkIn(dst_addr, alias_addr,
1747 0/* any */, alias_call_id,
1748 LINK_PPTP, 0);
1749
1750
1751 return (link);
1752 }
1753
1754
1755 struct alias_link *
1756 FindRtspOut(struct in_addr src_addr,
1757 struct in_addr dst_addr,
1758 u_short src_port,
1759 u_short alias_port,
1760 u_char proto)
1761 {
1762 int link_type;
1763 struct alias_link *link;
1764
1765 switch (proto)
1766 {
1767 case IPPROTO_UDP:
1768 link_type = LINK_UDP;
1769 break;
1770 case IPPROTO_TCP:
1771 link_type = LINK_TCP;
1772 break;
1773 default:
1774 return NULL;
1775 break;
1776 }
1777
1778 link = FindLinkOut(src_addr, dst_addr, src_port, 0, link_type, 1);
1779
1780 if (link == NULL)
1781 {
1782 struct in_addr alias_addr;
1783
1784 alias_addr = FindAliasAddress(src_addr);
1785 link = AddLink(src_addr, dst_addr, alias_addr,
1786 src_port, 0, alias_port,
1787 link_type);
1788 }
1789
1790 return(link);
1791 }
1792
1793
1794 struct in_addr
1795 FindOriginalAddress(struct in_addr alias_addr)
1796 {
1797 struct alias_link *link;
1798
1799 link = FindLinkIn(nullAddress, alias_addr,
1800 0, 0, LINK_ADDR, 0);
1801 if (link == NULL)
1802 {
1803 newDefaultLink = 1;
1804 if (targetAddress.s_addr == INADDR_ANY)
1805 return alias_addr;
1806 else if (targetAddress.s_addr == INADDR_NONE)
1807 return aliasAddress;
1808 else
1809 return targetAddress;
1810 }
1811 else
1812 {
1813 if (link->server != NULL) { /* LSNAT link */
1814 struct in_addr src_addr;
1815
1816 src_addr = link->server->addr;
1817 link->server = link->server->next;
1818 return (src_addr);
1819 } else if (link->src_addr.s_addr == INADDR_ANY)
1820 return aliasAddress;
1821 else
1822 return link->src_addr;
1823 }
1824 }
1825
1826
1827 struct in_addr
1828 FindAliasAddress(struct in_addr original_addr)
1829 {
1830 struct alias_link *link;
1831
1832 link = FindLinkOut(original_addr, nullAddress,
1833 0, 0, LINK_ADDR, 0);
1834 if (link == NULL)
1835 {
1836 return aliasAddress;
1837 }
1838 else
1839 {
1840 if (link->alias_addr.s_addr == INADDR_ANY)
1841 return aliasAddress;
1842 else
1843 return link->alias_addr;
1844 }
1845 }
1846
1847
1848 /* External routines for getting or changing link data
1849 (external to alias_db.c, but internal to alias*.c)
1850
1851 SetFragmentData(), GetFragmentData()
1852 SetFragmentPtr(), GetFragmentPtr()
1853 SetStateIn(), SetStateOut(), GetStateIn(), GetStateOut()
1854 GetOriginalAddress(), GetDestAddress(), GetAliasAddress()
1855 GetOriginalPort(), GetAliasPort()
1856 SetAckModified(), GetAckModified()
1857 GetDeltaAckIn(), GetDeltaSeqOut(), AddSeq()
1858 SetLastLineCrlfTermed(), GetLastLineCrlfTermed()
1859 SetDestCallId()
1860 */
1861
1862
1863 void
1864 SetFragmentAddr(struct alias_link *link, struct in_addr src_addr)
1865 {
1866 link->data.frag_addr = src_addr;
1867 }
1868
1869
1870 void
1871 GetFragmentAddr(struct alias_link *link, struct in_addr *src_addr)
1872 {
1873 *src_addr = link->data.frag_addr;
1874 }
1875
1876
1877 void
1878 SetFragmentPtr(struct alias_link *link, char *fptr)
1879 {
1880 link->data.frag_ptr = fptr;
1881 }
1882
1883
1884 void
1885 GetFragmentPtr(struct alias_link *link, char **fptr)
1886 {
1887 *fptr = link->data.frag_ptr;
1888 }
1889
1890
1891 void
1892 SetStateIn(struct alias_link *link, int state)
1893 {
1894 /* TCP input state */
1895 switch (state) {
1896 case ALIAS_TCP_STATE_DISCONNECTED:
1897 if (link->data.tcp->state.out != ALIAS_TCP_STATE_CONNECTED)
1898 link->expire_time = TCP_EXPIRE_DEAD;
1899 else
1900 link->expire_time = TCP_EXPIRE_SINGLEDEAD;
1901 break;
1902 case ALIAS_TCP_STATE_CONNECTED:
1903 if (link->data.tcp->state.out == ALIAS_TCP_STATE_CONNECTED)
1904 link->expire_time = TCP_EXPIRE_CONNECTED;
1905 break;
1906 default:
1907 abort();
1908 }
1909 link->data.tcp->state.in = state;
1910 }
1911
1912
1913 void
1914 SetStateOut(struct alias_link *link, int state)
1915 {
1916 /* TCP output state */
1917 switch (state) {
1918 case ALIAS_TCP_STATE_DISCONNECTED:
1919 if (link->data.tcp->state.in != ALIAS_TCP_STATE_CONNECTED)
1920 link->expire_time = TCP_EXPIRE_DEAD;
1921 else
1922 link->expire_time = TCP_EXPIRE_SINGLEDEAD;
1923 break;
1924 case ALIAS_TCP_STATE_CONNECTED:
1925 if (link->data.tcp->state.in == ALIAS_TCP_STATE_CONNECTED)
1926 link->expire_time = TCP_EXPIRE_CONNECTED;
1927 break;
1928 default:
1929 abort();
1930 }
1931 link->data.tcp->state.out = state;
1932 }
1933
1934
1935 int
1936 GetStateIn(struct alias_link *link)
1937 {
1938 /* TCP input state */
1939 return link->data.tcp->state.in;
1940 }
1941
1942
1943 int
1944 GetStateOut(struct alias_link *link)
1945 {
1946 /* TCP output state */
1947 return link->data.tcp->state.out;
1948 }
1949
1950
1951 struct in_addr
1952 GetOriginalAddress(struct alias_link *link)
1953 {
1954 if (link->src_addr.s_addr == INADDR_ANY)
1955 return aliasAddress;
1956 else
1957 return(link->src_addr);
1958 }
1959
1960
1961 struct in_addr
1962 GetDestAddress(struct alias_link *link)
1963 {
1964 return(link->dst_addr);
1965 }
1966
1967
1968 struct in_addr
1969 GetAliasAddress(struct alias_link *link)
1970 {
1971 if (link->alias_addr.s_addr == INADDR_ANY)
1972 return aliasAddress;
1973 else
1974 return link->alias_addr;
1975 }
1976
1977
1978 struct in_addr
1979 GetDefaultAliasAddress()
1980 {
1981 return aliasAddress;
1982 }
1983
1984
1985 void
1986 SetDefaultAliasAddress(struct in_addr alias_addr)
1987 {
1988 aliasAddress = alias_addr;
1989 }
1990
1991
1992 u_short
1993 GetOriginalPort(struct alias_link *link)
1994 {
1995 return(link->src_port);
1996 }
1997
1998
1999 u_short
2000 GetAliasPort(struct alias_link *link)
2001 {
2002 return(link->alias_port);
2003 }
2004
2005 #ifndef NO_FW_PUNCH
2006 static u_short
2007 GetDestPort(struct alias_link *link)
2008 {
2009 return(link->dst_port);
2010 }
2011 #endif
2012
2013 void
2014 SetAckModified(struct alias_link *link)
2015 {
2016 /* Indicate that ACK numbers have been modified in a TCP connection */
2017 link->data.tcp->state.ack_modified = 1;
2018 }
2019
2020
2021 struct in_addr
2022 GetProxyAddress(struct alias_link *link)
2023 {
2024 return link->proxy_addr;
2025 }
2026
2027
2028 void
2029 SetProxyAddress(struct alias_link *link, struct in_addr addr)
2030 {
2031 link->proxy_addr = addr;
2032 }
2033
2034
2035 u_short
2036 GetProxyPort(struct alias_link *link)
2037 {
2038 return link->proxy_port;
2039 }
2040
2041
2042 void
2043 SetProxyPort(struct alias_link *link, u_short port)
2044 {
2045 link->proxy_port = port;
2046 }
2047
2048
2049 int
2050 GetAckModified(struct alias_link *link)
2051 {
2052 /* See if ACK numbers have been modified */
2053 return link->data.tcp->state.ack_modified;
2054 }
2055
2056
2057 int
2058 GetDeltaAckIn(struct ip *pip, struct alias_link *link)
2059 {
2060 /*
2061 Find out how much the ACK number has been altered for an incoming
2062 TCP packet. To do this, a circular list of ACK numbers where the TCP
2063 packet size was altered is searched.
2064 */
2065
2066 int i;
2067 struct tcphdr *tc;
2068 int delta, ack_diff_min;
2069 u_long ack;
2070
2071 tc = (struct tcphdr *) ((char *) pip + (pip->ip_hl << 2));
2072 ack = tc->th_ack;
2073
2074 delta = 0;
2075 ack_diff_min = -1;
2076 for (i=0; i<N_LINK_TCP_DATA; i++)
2077 {
2078 struct ack_data_record x;
2079
2080 x = link->data.tcp->ack[i];
2081 if (x.active == 1)
2082 {
2083 int ack_diff;
2084
2085 ack_diff = SeqDiff(x.ack_new, ack);
2086 if (ack_diff >= 0)
2087 {
2088 if (ack_diff_min >= 0)
2089 {
2090 if (ack_diff < ack_diff_min)
2091 {
2092 delta = x.delta;
2093 ack_diff_min = ack_diff;
2094 }
2095 }
2096 else
2097 {
2098 delta = x.delta;
2099 ack_diff_min = ack_diff;
2100 }
2101 }
2102 }
2103 }
2104 return (delta);
2105 }
2106
2107
2108 int
2109 GetDeltaSeqOut(struct ip *pip, struct alias_link *link)
2110 {
2111 /*
2112 Find out how much the sequence number has been altered for an outgoing
2113 TCP packet. To do this, a circular list of ACK numbers where the TCP
2114 packet size was altered is searched.
2115 */
2116
2117 int i;
2118 struct tcphdr *tc;
2119 int delta, seq_diff_min;
2120 u_long seq;
2121
2122 tc = (struct tcphdr *) ((char *) pip + (pip->ip_hl << 2));
2123 seq = tc->th_seq;
2124
2125 delta = 0;
2126 seq_diff_min = -1;
2127 for (i=0; i<N_LINK_TCP_DATA; i++)
2128 {
2129 struct ack_data_record x;
2130
2131 x = link->data.tcp->ack[i];
2132 if (x.active == 1)
2133 {
2134 int seq_diff;
2135
2136 seq_diff = SeqDiff(x.ack_old, seq);
2137 if (seq_diff >= 0)
2138 {
2139 if (seq_diff_min >= 0)
2140 {
2141 if (seq_diff < seq_diff_min)
2142 {
2143 delta = x.delta;
2144 seq_diff_min = seq_diff;
2145 }
2146 }
2147 else
2148 {
2149 delta = x.delta;
2150 seq_diff_min = seq_diff;
2151 }
2152 }
2153 }
2154 }
2155 return (delta);
2156 }
2157
2158
2159 void
2160 AddSeq(struct ip *pip, struct alias_link *link, int delta)
2161 {
2162 /*
2163 When a TCP packet has been altered in length, save this
2164 information in a circular list. If enough packets have
2165 been altered, then this list will begin to overwrite itself.
2166 */
2167
2168 struct tcphdr *tc;
2169 struct ack_data_record x;
2170 int hlen, tlen, dlen;
2171 int i;
2172
2173 tc = (struct tcphdr *) ((char *) pip + (pip->ip_hl << 2));
2174
2175 hlen = (pip->ip_hl + tc->th_off) << 2;
2176 tlen = ntohs(pip->ip_len);
2177 dlen = tlen - hlen;
2178
2179 x.ack_old = htonl(ntohl(tc->th_seq) + dlen);
2180 x.ack_new = htonl(ntohl(tc->th_seq) + dlen + delta);
2181 x.delta = delta;
2182 x.active = 1;
2183
2184 i = link->data.tcp->state.index;
2185 link->data.tcp->ack[i] = x;
2186
2187 i++;
2188 if (i == N_LINK_TCP_DATA)
2189 link->data.tcp->state.index = 0;
2190 else
2191 link->data.tcp->state.index = i;
2192 }
2193
2194 void
2195 SetExpire(struct alias_link *link, int expire)
2196 {
2197 if (expire == 0)
2198 {
2199 link->flags &= ~LINK_PERMANENT;
2200 DeleteLink(link);
2201 }
2202 else if (expire == -1)
2203 {
2204 link->flags |= LINK_PERMANENT;
2205 }
2206 else if (expire > 0)
2207 {
2208 link->expire_time = expire;
2209 }
2210 else
2211 {
2212 #ifdef DEBUG
2213 fprintf(stderr, "PacketAlias/SetExpire(): ");
2214 fprintf(stderr, "error in expire parameter\n");
2215 #endif
2216 }
2217 }
2218
2219 void
2220 ClearCheckNewLink(void)
2221 {
2222 newDefaultLink = 0;
2223 }
2224
2225 void
2226 SetLastLineCrlfTermed(struct alias_link *link, int yes)
2227 {
2228
2229 if (yes)
2230 link->flags |= LINK_LAST_LINE_CRLF_TERMED;
2231 else
2232 link->flags &= ~LINK_LAST_LINE_CRLF_TERMED;
2233 }
2234
2235 int
2236 GetLastLineCrlfTermed(struct alias_link *link)
2237 {
2238
2239 return (link->flags & LINK_LAST_LINE_CRLF_TERMED);
2240 }
2241
2242 void
2243 SetDestCallId(struct alias_link *link, u_int16_t cid)
2244 {
2245
2246 deleteAllLinks = 1;
2247 link = ReLink(link, link->src_addr, link->dst_addr, link->alias_addr,
2248 link->src_port, cid, link->alias_port, link->link_type);
2249 deleteAllLinks = 0;
2250 }
2251
2252
2253 /* Miscellaneous Functions
2254
2255 HouseKeeping()
2256 InitPacketAliasLog()
2257 UninitPacketAliasLog()
2258 */
2259
2260 /*
2261 Whenever an outgoing or incoming packet is handled, HouseKeeping()
2262 is called to find and remove timed-out aliasing links. Logic exists
2263 to sweep through the entire table and linked list structure
2264 every 60 seconds.
2265
2266 (prototype in alias_local.h)
2267 */
2268
2269 void
2270 HouseKeeping(void)
2271 {
2272 int i, n, n100;
2273 struct timeval tv;
2274 struct timezone tz;
2275
2276 /*
2277 * Save system time (seconds) in global variable timeStamp for
2278 * use by other functions. This is done so as not to unnecessarily
2279 * waste timeline by making system calls.
2280 */
2281 gettimeofday(&tv, &tz);
2282 timeStamp = tv.tv_sec;
2283
2284 /* Compute number of spokes (output table link chains) to cover */
2285 n100 = LINK_TABLE_OUT_SIZE * 100 + houseKeepingResidual;
2286 n100 *= timeStamp - lastCleanupTime;
2287 n100 /= ALIAS_CLEANUP_INTERVAL_SECS;
2288
2289 n = n100/100;
2290
2291 /* Handle different cases */
2292 if (n > ALIAS_CLEANUP_MAX_SPOKES)
2293 {
2294 n = ALIAS_CLEANUP_MAX_SPOKES;
2295 lastCleanupTime = timeStamp;
2296 houseKeepingResidual = 0;
2297
2298 for (i=0; i<n; i++)
2299 IncrementalCleanup();
2300 }
2301 else if (n > 0)
2302 {
2303 lastCleanupTime = timeStamp;
2304 houseKeepingResidual = n100 - 100*n;
2305
2306 for (i=0; i<n; i++)
2307 IncrementalCleanup();
2308 }
2309 else if (n < 0)
2310 {
2311 #ifdef DEBUG
2312 fprintf(stderr, "PacketAlias/HouseKeeping(): ");
2313 fprintf(stderr, "something unexpected in time values\n");
2314 #endif
2315 lastCleanupTime = timeStamp;
2316 houseKeepingResidual = 0;
2317 }
2318 }
2319
2320
2321 /* Init the log file and enable logging */
2322 static void
2323 InitPacketAliasLog(void)
2324 {
2325 if ((~packetAliasMode & PKT_ALIAS_LOG)
2326 && (monitorFile = fopen("/var/log/alias.log", "w")))
2327 {
2328 packetAliasMode |= PKT_ALIAS_LOG;
2329 fprintf(monitorFile,
2330 "PacketAlias/InitPacketAliasLog: Packet alias logging enabled.\n");
2331 }
2332 }
2333
2334
2335 /* Close the log-file and disable logging. */
2336 static void
2337 UninitPacketAliasLog(void)
2338 {
2339 if (monitorFile) {
2340 fclose(monitorFile);
2341 monitorFile = NULL;
2342 }
2343 packetAliasMode &= ~PKT_ALIAS_LOG;
2344 }
2345
2346
2347
2348
2349
2350
2351 /* Outside world interfaces
2352
2353 -- "outside world" means other than alias*.c routines --
2354
2355 PacketAliasRedirectPort()
2356 PacketAliasAddServer()
2357 PacketAliasRedirectProto()
2358 PacketAliasRedirectAddr()
2359 PacketAliasRedirectDelete()
2360 PacketAliasSetAddress()
2361 PacketAliasInit()
2362 PacketAliasUninit()
2363 PacketAliasSetMode()
2364
2365 (prototypes in alias.h)
2366 */
2367
2368 /* Redirection from a specific public addr:port to a
2369 private addr:port */
2370 struct alias_link *
2371 PacketAliasRedirectPort(struct in_addr src_addr, u_short src_port,
2372 struct in_addr dst_addr, u_short dst_port,
2373 struct in_addr alias_addr, u_short alias_port,
2374 u_char proto)
2375 {
2376 int link_type;
2377 struct alias_link *link;
2378
2379 switch(proto)
2380 {
2381 case IPPROTO_UDP:
2382 link_type = LINK_UDP;
2383 break;
2384 case IPPROTO_TCP:
2385 link_type = LINK_TCP;
2386 break;
2387 default:
2388 #ifdef DEBUG
2389 fprintf(stderr, "PacketAliasRedirectPort(): ");
2390 fprintf(stderr, "only TCP and UDP protocols allowed\n");
2391 #endif
2392 return NULL;
2393 }
2394
2395 link = AddLink(src_addr, dst_addr, alias_addr,
2396 src_port, dst_port, alias_port,
2397 link_type);
2398
2399 if (link != NULL)
2400 {
2401 link->flags |= LINK_PERMANENT;
2402 }
2403 #ifdef DEBUG
2404 else
2405 {
2406 fprintf(stderr, "PacketAliasRedirectPort(): "
2407 "call to AddLink() failed\n");
2408 }
2409 #endif
2410
2411 return link;
2412 }
2413
2414 /* Add server to the pool of servers */
2415 int
2416 PacketAliasAddServer(struct alias_link *link, struct in_addr addr, u_short port)
2417 {
2418 struct server *server;
2419
2420 server = malloc(sizeof(struct server));
2421
2422 if (server != NULL) {
2423 struct server *head;
2424
2425 server->addr = addr;
2426 server->port = port;
2427
2428 head = link->server;
2429 if (head == NULL)
2430 server->next = server;
2431 else {
2432 struct server *s;
2433
2434 for (s = head; s->next != head; s = s->next);
2435 s->next = server;
2436 server->next = head;
2437 }
2438 link->server = server;
2439 return (0);
2440 } else
2441 return (-1);
2442 }
2443
2444 /* Redirect packets of a given IP protocol from a specific
2445 public address to a private address */
2446 struct alias_link *
2447 PacketAliasRedirectProto(struct in_addr src_addr,
2448 struct in_addr dst_addr,
2449 struct in_addr alias_addr,
2450 u_char proto)
2451 {
2452 struct alias_link *link;
2453
2454 link = AddLink(src_addr, dst_addr, alias_addr,
2455 NO_SRC_PORT, NO_DEST_PORT, 0,
2456 proto);
2457
2458 if (link != NULL)
2459 {
2460 link->flags |= LINK_PERMANENT;
2461 }
2462 #ifdef DEBUG
2463 else
2464 {
2465 fprintf(stderr, "PacketAliasRedirectProto(): "
2466 "call to AddLink() failed\n");
2467 }
2468 #endif
2469
2470 return link;
2471 }
2472
2473 /* Static address translation */
2474 struct alias_link *
2475 PacketAliasRedirectAddr(struct in_addr src_addr,
2476 struct in_addr alias_addr)
2477 {
2478 struct alias_link *link;
2479
2480 link = AddLink(src_addr, nullAddress, alias_addr,
2481 0, 0, 0,
2482 LINK_ADDR);
2483
2484 if (link != NULL)
2485 {
2486 link->flags |= LINK_PERMANENT;
2487 }
2488 #ifdef DEBUG
2489 else
2490 {
2491 fprintf(stderr, "PacketAliasRedirectAddr(): "
2492 "call to AddLink() failed\n");
2493 }
2494 #endif
2495
2496 return link;
2497 }
2498
2499
2500 void
2501 PacketAliasRedirectDelete(struct alias_link *link)
2502 {
2503 /* This is a dangerous function to put in the API,
2504 because an invalid pointer can crash the program. */
2505
2506 deleteAllLinks = 1;
2507 DeleteLink(link);
2508 deleteAllLinks = 0;
2509 }
2510
2511
2512 void
2513 PacketAliasSetAddress(struct in_addr addr)
2514 {
2515 if (packetAliasMode & PKT_ALIAS_RESET_ON_ADDR_CHANGE
2516 && aliasAddress.s_addr != addr.s_addr)
2517 CleanupAliasData();
2518
2519 aliasAddress = addr;
2520 }
2521
2522
2523 void
2524 PacketAliasSetTarget(struct in_addr target_addr)
2525 {
2526 targetAddress = target_addr;
2527 }
2528
2529
2530 void
2531 PacketAliasInit(void)
2532 {
2533 int i;
2534 struct timeval tv;
2535 struct timezone tz;
2536 static int firstCall = 1;
2537
2538 if (firstCall == 1)
2539 {
2540 gettimeofday(&tv, &tz);
2541 timeStamp = tv.tv_sec;
2542 lastCleanupTime = tv.tv_sec;
2543 houseKeepingResidual = 0;
2544
2545 for (i=0; i<LINK_TABLE_OUT_SIZE; i++)
2546 LIST_INIT(&linkTableOut[i]);
2547 for (i=0; i<LINK_TABLE_IN_SIZE; i++)
2548 LIST_INIT(&linkTableIn[i]);
2549
2550 atexit(PacketAliasUninit);
2551 firstCall = 0;
2552 }
2553 else
2554 {
2555 deleteAllLinks = 1;
2556 CleanupAliasData();
2557 deleteAllLinks = 0;
2558 }
2559
2560 aliasAddress.s_addr = INADDR_ANY;
2561 targetAddress.s_addr = INADDR_ANY;
2562
2563 icmpLinkCount = 0;
2564 udpLinkCount = 0;
2565 tcpLinkCount = 0;
2566 pptpLinkCount = 0;
2567 protoLinkCount = 0;
2568 fragmentIdLinkCount = 0;
2569 fragmentPtrLinkCount = 0;
2570 sockCount = 0;
2571
2572 cleanupIndex =0;
2573
2574 packetAliasMode = PKT_ALIAS_SAME_PORTS
2575 | PKT_ALIAS_USE_SOCKETS
2576 | PKT_ALIAS_RESET_ON_ADDR_CHANGE;
2577 }
2578
2579 void
2580 PacketAliasUninit(void) {
2581 deleteAllLinks = 1;
2582 CleanupAliasData();
2583 deleteAllLinks = 0;
2584 UninitPacketAliasLog();
2585 #ifndef NO_FW_PUNCH
2586 UninitPunchFW();
2587 #endif
2588 }
2589
2590
2591 /* Change mode for some operations */
2592 unsigned int
2593 PacketAliasSetMode(
2594 unsigned int flags, /* Which state to bring flags to */
2595 unsigned int mask /* Mask of which flags to affect (use 0 to do a
2596 probe for flag values) */
2597 )
2598 {
2599 /* Enable logging? */
2600 if (flags & mask & PKT_ALIAS_LOG)
2601 {
2602 InitPacketAliasLog(); /* Do the enable */
2603 } else
2604 /* _Disable_ logging? */
2605 if (~flags & mask & PKT_ALIAS_LOG) {
2606 UninitPacketAliasLog();
2607 }
2608
2609 #ifndef NO_FW_PUNCH
2610 /* Start punching holes in the firewall? */
2611 if (flags & mask & PKT_ALIAS_PUNCH_FW) {
2612 InitPunchFW();
2613 } else
2614 /* Stop punching holes in the firewall? */
2615 if (~flags & mask & PKT_ALIAS_PUNCH_FW) {
2616 UninitPunchFW();
2617 }
2618 #endif
2619
2620 /* Other flags can be set/cleared without special action */
2621 packetAliasMode = (flags & mask) | (packetAliasMode & ~mask);
2622 return packetAliasMode;
2623 }
2624
2625
2626 int
2627 PacketAliasCheckNewLink(void)
2628 {
2629 return newDefaultLink;
2630 }
2631
2632
2633 #ifndef NO_FW_PUNCH
2634
2635 /*****************
2636 Code to support firewall punching. This shouldn't really be in this
2637 file, but making variables global is evil too.
2638 ****************/
2639
2640 /* Firewall include files */
2641 #include <net/if.h>
2642 #include <net/ipfw/ip_fw.h>
2643 #include <string.h>
2644 #include <err.h>
2645
2646 /*
2647 * helper function, updates the pointer to cmd with the length
2648 * of the current command, and also cleans up the first word of
2649 * the new command in case it has been clobbered before.
2650 */
2651 static ipfw_insn *
2652 next_cmd(ipfw_insn *cmd)
2653 {
2654 cmd += F_LEN(cmd);
2655 bzero(cmd, sizeof(*cmd));
2656 return cmd;
2657 }
2658
2659 /*
2660 * A function to fill simple commands of size 1.
2661 * Existing flags are preserved.
2662 */
2663 static ipfw_insn *
2664 fill_cmd(ipfw_insn *cmd, enum ipfw_opcodes opcode, int size,
2665 int flags, u_int16_t arg)
2666 {
2667 cmd->opcode = opcode;
2668 cmd->len = ((cmd->len | flags) & (F_NOT | F_OR)) | (size & F_LEN_MASK);
2669 cmd->arg1 = arg;
2670 return next_cmd(cmd);
2671 }
2672
2673 static ipfw_insn *
2674 fill_ip(ipfw_insn *cmd1, enum ipfw_opcodes opcode, u_int32_t addr)
2675 {
2676 ipfw_insn_ip *cmd = (ipfw_insn_ip *)cmd1;
2677
2678 cmd->addr.s_addr = addr;
2679 return fill_cmd(cmd1, opcode, F_INSN_SIZE(ipfw_insn_u32), 0, 0);
2680 }
2681
2682 static ipfw_insn *
2683 fill_one_port(ipfw_insn *cmd1, enum ipfw_opcodes opcode, u_int16_t port)
2684 {
2685 ipfw_insn_u16 *cmd = (ipfw_insn_u16 *)cmd1;
2686
2687 cmd->ports[0] = cmd->ports[1] = port;
2688 return fill_cmd(cmd1, opcode, F_INSN_SIZE(ipfw_insn_u16), 0, 0);
2689 }
2690
2691 static int
2692 fill_rule(void *buf, int bufsize, int rulenum,
2693 enum ipfw_opcodes action, int proto,
2694 struct in_addr sa, u_int16_t sp, struct in_addr da, u_int16_t dp)
2695 {
2696 struct ipfw_ioc_rule *rule = buf;
2697 ipfw_insn *cmd = (ipfw_insn *)rule->cmd;
2698
2699 bzero(buf, bufsize);
2700 rule->rulenum = rulenum;
2701
2702 cmd = fill_cmd(cmd, O_PROTO, F_INSN_SIZE(ipfw_insn), 0, proto);
2703 cmd = fill_ip(cmd, O_IP_SRC, sa.s_addr);
2704 cmd = fill_one_port(cmd, O_IP_SRCPORT, sp);
2705 cmd = fill_ip(cmd, O_IP_DST, da.s_addr);
2706 cmd = fill_one_port(cmd, O_IP_DSTPORT, dp);
2707
2708 rule->act_ofs = (u_int32_t *)cmd - (u_int32_t *)rule->cmd;
2709 cmd = fill_cmd(cmd, action, F_INSN_SIZE(ipfw_insn), 0, 0);
2710
2711 rule->cmd_len = (u_int32_t *)cmd - (u_int32_t *)rule->cmd;
2712
2713 return ((void *)cmd - buf);
2714 }
2715
2716 static void ClearAllFWHoles(void);
2717
2718 static int fireWallBaseNum; /* The first firewall entry free for our use */
2719 static int fireWallNumNums; /* How many entries can we use? */
2720 static int fireWallActiveNum; /* Which entry did we last use? */
2721 static char *fireWallField; /* bool array for entries */
2722
2723 #define fw_setfield(field, num) \
2724 do { \
2725 (field)[(num) - fireWallBaseNum] = 1; \
2726 } /*lint -save -e717 */ while(0) /*lint -restore */
2727 #define fw_clrfield(field, num) \
2728 do { \
2729 (field)[(num) - fireWallBaseNum] = 0; \
2730 } /*lint -save -e717 */ while(0) /*lint -restore */
2731 #define fw_tstfield(field, num) ((field)[(num) - fireWallBaseNum])
2732
2733 static void
2734 InitPunchFW(void) {
2735 fireWallField = malloc(fireWallNumNums);
2736 if (fireWallField) {
2737 memset(fireWallField, 0, fireWallNumNums);
2738 if (fireWallFD < 0) {
2739 fireWallFD = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
2740 }
2741 ClearAllFWHoles();
2742 fireWallActiveNum = fireWallBaseNum;
2743 }
2744 }
2745
2746 static void
2747 UninitPunchFW(void) {
2748 ClearAllFWHoles();
2749 if (fireWallFD >= 0)
2750 close(fireWallFD);
2751 fireWallFD = -1;
2752 if (fireWallField)
2753 free(fireWallField);
2754 fireWallField = NULL;
2755 packetAliasMode &= ~PKT_ALIAS_PUNCH_FW;
2756 }
2757
2758 /* Make a certain link go through the firewall */
2759 void
2760 PunchFWHole(struct alias_link *link) {
2761 int r; /* Result code */
2762 int fwhole; /* Where to punch hole */
2763
2764 /* Don't do anything unless we are asked to */
2765 if ( !(packetAliasMode & PKT_ALIAS_PUNCH_FW) ||
2766 fireWallFD < 0 ||
2767 link->link_type != LINK_TCP)
2768 return;
2769
2770 /** Build rule **/
2771
2772 /* Find empty slot */
2773 for (fwhole = fireWallActiveNum;
2774 fwhole < fireWallBaseNum + fireWallNumNums &&
2775 fw_tstfield(fireWallField, fwhole);
2776 fwhole++)
2777 ;
2778 if (fwhole == fireWallBaseNum + fireWallNumNums) {
2779 for (fwhole = fireWallBaseNum;
2780 fwhole < fireWallActiveNum &&
2781 fw_tstfield(fireWallField, fwhole);
2782 fwhole++)
2783 ;
2784 if (fwhole == fireWallActiveNum) {
2785 /* No rule point empty - we can't punch more holes. */
2786 fireWallActiveNum = fireWallBaseNum;
2787 #ifdef DEBUG
2788 fprintf(stderr, "libalias: Unable to create firewall hole!\n");
2789 #endif
2790 return;
2791 }
2792 }
2793 /* Start next search at next position */
2794 fireWallActiveNum = fwhole+1;
2795
2796 /*
2797 * generate two rules of the form
2798 *
2799 * add fwhole accept tcp from OAddr OPort to DAddr DPort
2800 * add fwhole accept tcp from DAddr DPort to OAddr OPort
2801 */
2802 if (GetOriginalPort(link) != 0 && GetDestPort(link) != 0) {
2803 u_int32_t rulebuf[IPFW_RULE_SIZE_MAX];
2804 int i;
2805
2806 i = fill_rule(rulebuf, sizeof(rulebuf), fwhole,
2807 O_ACCEPT, IPPROTO_TCP,
2808 GetOriginalAddress(link), ntohs(GetOriginalPort(link)),
2809 GetDestAddress(link), ntohs(GetDestPort(link)) );
2810 r = setsockopt(fireWallFD, IPPROTO_IP, IP_FW_ADD, rulebuf, i);
2811 if (r)
2812 err(1, "alias punch inbound(1) setsockopt(IP_FW_ADD)");
2813
2814 i = fill_rule(rulebuf, sizeof(rulebuf), fwhole,
2815 O_ACCEPT, IPPROTO_TCP,
2816 GetDestAddress(link), ntohs(GetDestPort(link)),
2817 GetOriginalAddress(link), ntohs(GetOriginalPort(link)) );
2818 r = setsockopt(fireWallFD, IPPROTO_IP, IP_FW_ADD, rulebuf, i);
2819 if (r)
2820 err(1, "alias punch inbound(2) setsockopt(IP_FW_ADD)");
2821 }
2822 /* Indicate hole applied */
2823 link->data.tcp->fwhole = fwhole;
2824 fw_setfield(fireWallField, fwhole);
2825 }
2826
2827 /* Remove a hole in a firewall associated with a particular alias
2828 link. Calling this too often is harmless. */
2829 static void
2830 ClearFWHole(struct alias_link *link) {
2831 if (link->link_type == LINK_TCP) {
2832 int fwhole = link->data.tcp->fwhole; /* Where is the firewall hole? */
2833
2834 if (fwhole < 0)
2835 return;
2836
2837 while (!setsockopt(fireWallFD, IPPROTO_IP, IP_FW_DEL,
2838 &fwhole, sizeof fwhole))
2839 ;
2840 fw_clrfield(fireWallField, fwhole);
2841 link->data.tcp->fwhole = -1;
2842 }
2843 }
2844
2845 /* Clear out the entire range dedicated to firewall holes. */
2846 static void
2847 ClearAllFWHoles(void) {
2848 int i;
2849
2850 if (fireWallFD < 0)
2851 return;
2852
2853 for (i = fireWallBaseNum; i < fireWallBaseNum + fireWallNumNums; i++) {
2854 int r = i;
2855 while (!setsockopt(fireWallFD, IPPROTO_IP, IP_FW_DEL, &r, sizeof r))
2856 ;
2857 }
2858 memset(fireWallField, 0, fireWallNumNums);
2859 }
2860 #endif
2861
2862 void
2863 PacketAliasSetFWBase(unsigned int base, unsigned int num) {
2864 #ifndef NO_FW_PUNCH
2865 fireWallBaseNum = base;
2866 fireWallNumNums = num;
2867 #endif
2868 }
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