1 /*-
2 * Copyright (c) 2001 Charles Mott <cm@linktel.net>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD$
27 */
28
29 /*
30 * Alias_local.h contains the function prototypes for alias.c,
31 * alias_db.c, alias_util.c and alias_ftp.c, alias_irc.c (as well
32 * as any future add-ons). It also includes macros, globals and
33 * struct definitions shared by more than one alias*.c file.
34 *
35 * This include file is intended to be used only within the aliasing
36 * software. Outside world interfaces are defined in alias.h
37 *
38 * This software is placed into the public domain with no restrictions
39 * on its distribution.
40 *
41 * Initial version: August, 1996 (cjm)
42 *
43 * <updated several times by original author and Eivind Eklund>
44 */
45
46 #ifndef _ALIAS_LOCAL_H_
47 #define _ALIAS_LOCAL_H_
48
49 #include <sys/types.h>
50 #include <sys/sysctl.h>
51
52 #ifdef _KERNEL
53 #include <sys/malloc.h>
54 #include <sys/param.h>
55 #include <sys/lock.h>
56 #include <sys/mutex.h>
57
58 /* XXX: LibAliasSetTarget() uses this constant. */
59 #define INADDR_NONE 0xffffffff
60
61 #include <netinet/libalias/alias_sctp.h>
62 #else
63 #include "alias_sctp.h"
64 #endif
65
66 /* Sizes of input and output link tables */
67 #define LINK_TABLE_OUT_SIZE 4001
68 #define LINK_TABLE_IN_SIZE 4001
69
70 #define GET_ALIAS_PORT -1
71 #define GET_ALIAS_ID GET_ALIAS_PORT
72
73 #ifdef _KERNEL
74 #define INET_NTOA_BUF(buf) (buf)
75 #else
76 #define INET_NTOA_BUF(buf) (buf), sizeof(buf)
77 #endif
78
79 struct proxy_entry;
80
81 struct libalias {
82 LIST_ENTRY(libalias) instancelist;
83
84 int packetAliasMode; /* Mode flags */
85 /* - documented in alias.h */
86
87 struct in_addr aliasAddress; /* Address written onto source */
88 /* field of IP packet. */
89
90 struct in_addr targetAddress; /* IP address incoming packets */
91 /* are sent to if no aliasing */
92 /* link already exists */
93
94 struct in_addr nullAddress; /* Used as a dummy parameter for */
95 /* some function calls */
96
97 LIST_HEAD (, alias_link) linkTableOut[LINK_TABLE_OUT_SIZE];
98 /* Lookup table of pointers to */
99 /* chains of link records. Each */
100
101 LIST_HEAD (, alias_link) linkTableIn[LINK_TABLE_IN_SIZE];
102 /* link record is doubly indexed */
103 /* into input and output lookup */
104 /* tables. */
105
106 /* Link statistics */
107 int icmpLinkCount;
108 int udpLinkCount;
109 int tcpLinkCount;
110 int pptpLinkCount;
111 int protoLinkCount;
112 int fragmentIdLinkCount;
113 int fragmentPtrLinkCount;
114 int sockCount;
115
116 int cleanupIndex; /* Index to chain of link table */
117 /* being inspected for old links */
118
119 int timeStamp; /* System time in seconds for */
120 /* current packet */
121
122 int lastCleanupTime; /* Last time
123 * IncrementalCleanup() */
124 /* was called */
125
126 int deleteAllLinks; /* If equal to zero, DeleteLink() */
127 /* will not remove permanent links */
128
129 /* log descriptor */
130 #ifdef _KERNEL
131 char *logDesc;
132 #else
133 FILE *logDesc;
134 #endif
135 /* statistics monitoring */
136
137 int newDefaultLink; /* Indicates if a new aliasing */
138 /* link has been created after a */
139 /* call to PacketAliasIn/Out(). */
140
141 #ifndef NO_FW_PUNCH
142 int fireWallFD; /* File descriptor to be able to */
143 /* control firewall. Opened by */
144 /* PacketAliasSetMode on first */
145 /* setting the PKT_ALIAS_PUNCH_FW */
146 /* flag. */
147 int fireWallBaseNum; /* The first firewall entry
148 * free for our use */
149 int fireWallNumNums; /* How many entries can we
150 * use? */
151 int fireWallActiveNum; /* Which entry did we last
152 * use? */
153 char *fireWallField; /* bool array for entries */
154 #endif
155
156 unsigned int skinnyPort; /* TCP port used by the Skinny */
157 /* protocol. */
158
159 struct proxy_entry *proxyList;
160
161 struct in_addr true_addr; /* in network byte order. */
162 u_short true_port; /* in host byte order. */
163
164 /*
165 * sctp code support
166 */
167
168 /* counts associations that have progressed to UP and not yet removed */
169 int sctpLinkCount;
170 #ifdef _KERNEL
171 /* timing queue for keeping track of association timeouts */
172 struct sctp_nat_timer sctpNatTimer;
173
174 /* size of hash table used in this instance */
175 u_int sctpNatTableSize;
176
177 /*
178 * local look up table sorted by l_vtag/l_port
179 */
180 LIST_HEAD(sctpNatTableL, sctp_nat_assoc) *sctpTableLocal;
181 /*
182 * global look up table sorted by g_vtag/g_port
183 */
184 LIST_HEAD(sctpNatTableG, sctp_nat_assoc) *sctpTableGlobal;
185
186 /*
187 * avoid races in libalias: every public function has to use it.
188 */
189 struct mtx mutex;
190 #endif
191 };
192
193 /* Macros */
194
195 #ifdef _KERNEL
196 #define LIBALIAS_LOCK_INIT(l) \
197 mtx_init(&l->mutex, "per-instance libalias mutex", NULL, MTX_DEF)
198 #define LIBALIAS_LOCK_ASSERT(l) mtx_assert(&l->mutex, MA_OWNED)
199 #define LIBALIAS_LOCK(l) mtx_lock(&l->mutex)
200 #define LIBALIAS_UNLOCK(l) mtx_unlock(&l->mutex)
201 #define LIBALIAS_LOCK_DESTROY(l) mtx_destroy(&l->mutex)
202 #else
203 #define LIBALIAS_LOCK_INIT(l)
204 #define LIBALIAS_LOCK_ASSERT(l)
205 #define LIBALIAS_LOCK(l)
206 #define LIBALIAS_UNLOCK(l)
207 #define LIBALIAS_LOCK_DESTROY(l)
208 #endif
209
210 /*
211 * The following macro is used to update an
212 * internet checksum. "delta" is a 32-bit
213 * accumulation of all the changes to the
214 * checksum (adding in new 16-bit words and
215 * subtracting out old words), and "cksum"
216 * is the checksum value to be updated.
217 */
218 #define ADJUST_CHECKSUM(acc, cksum) \
219 do { \
220 acc += cksum; \
221 if (acc < 0) { \
222 acc = -acc; \
223 acc = (acc >> 16) + (acc & 0xffff); \
224 acc += acc >> 16; \
225 cksum = (u_short) ~acc; \
226 } else { \
227 acc = (acc >> 16) + (acc & 0xffff); \
228 acc += acc >> 16; \
229 cksum = (u_short) acc; \
230 } \
231 } while (0)
232
233
234 /* Prototypes */
235
236 /*
237 * SctpFunction prototypes
238 *
239 */
240 void AliasSctpInit(struct libalias *la);
241 void AliasSctpTerm(struct libalias *la);
242 int SctpAlias(struct libalias *la, struct ip *ip, int direction);
243
244 /*
245 * We do not calculate TCP checksums when libalias is a kernel
246 * module, since it has no idea about checksum offloading.
247 * If TCP data has changed, then we just set checksum to zero,
248 * and caller must recalculate it himself.
249 * In case if libalias will edit UDP data, the same approach
250 * should be used.
251 */
252 #ifndef _KERNEL
253 u_short IpChecksum(struct ip *_pip);
254 u_short TcpChecksum(struct ip *_pip);
255 #endif
256 void
257 DifferentialChecksum(u_short * _cksum, void * _new, void * _old, int _n);
258
259 /* Internal data access */
260 struct alias_link *
261 AddLink(struct libalias *la, struct in_addr src_addr, struct in_addr dst_addr,
262 struct in_addr alias_addr, u_short src_port, u_short dst_port,
263 int alias_param, int link_type);
264 struct alias_link *
265 FindIcmpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
266 u_short _id_alias, int _create);
267 struct alias_link *
268 FindIcmpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
269 u_short _id, int _create);
270 struct alias_link *
271 FindFragmentIn1(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
272 u_short _ip_id);
273 struct alias_link *
274 FindFragmentIn2(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
275 u_short _ip_id);
276 struct alias_link *
277 AddFragmentPtrLink(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
278 struct alias_link *
279 FindFragmentPtr(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
280 struct alias_link *
281 FindProtoIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
282 u_char _proto);
283 struct alias_link *
284 FindProtoOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
285 u_char _proto);
286 struct alias_link *
287 FindUdpTcpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
288 u_short _dst_port, u_short _alias_port, u_char _proto, int _create);
289 struct alias_link *
290 FindUdpTcpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
291 u_short _src_port, u_short _dst_port, u_char _proto, int _create);
292 struct alias_link *
293 AddPptp(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
294 struct in_addr _alias_addr, u_int16_t _src_call_id);
295 struct alias_link *
296 FindPptpOutByCallId(struct libalias *la, struct in_addr _src_addr,
297 struct in_addr _dst_addr, u_int16_t _src_call_id);
298 struct alias_link *
299 FindPptpInByCallId(struct libalias *la, struct in_addr _dst_addr,
300 struct in_addr _alias_addr, u_int16_t _dst_call_id);
301 struct alias_link *
302 FindPptpOutByPeerCallId(struct libalias *la, struct in_addr _src_addr,
303 struct in_addr _dst_addr, u_int16_t _dst_call_id);
304 struct alias_link *
305 FindPptpInByPeerCallId(struct libalias *la, struct in_addr _dst_addr,
306 struct in_addr _alias_addr, u_int16_t _alias_call_id);
307 struct alias_link *
308 FindRtspOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
309 u_short _src_port, u_short _alias_port, u_char _proto);
310 struct in_addr
311 FindOriginalAddress(struct libalias *la, struct in_addr _alias_addr);
312 struct in_addr
313 FindAliasAddress(struct libalias *la, struct in_addr _original_addr);
314 struct in_addr
315 FindSctpRedirectAddress(struct libalias *la, struct sctp_nat_msg *sm);
316
317 /* External data access/modification */
318 int
319 FindNewPortGroup(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
320 u_short _src_port, u_short _dst_port, u_short _port_count,
321 u_char _proto, u_char _align);
322 void GetFragmentAddr(struct alias_link *_lnk, struct in_addr *_src_addr);
323 void SetFragmentAddr(struct alias_link *_lnk, struct in_addr _src_addr);
324 void GetFragmentPtr(struct alias_link *_lnk, char **_fptr);
325 void SetFragmentPtr(struct alias_link *_lnk, char *fptr);
326 void SetStateIn(struct alias_link *_lnk, int _state);
327 void SetStateOut(struct alias_link *_lnk, int _state);
328 int GetStateIn (struct alias_link *_lnk);
329 int GetStateOut(struct alias_link *_lnk);
330 struct in_addr
331 GetOriginalAddress(struct alias_link *_lnk);
332 struct in_addr
333 GetDestAddress(struct alias_link *_lnk);
334 struct in_addr
335 GetAliasAddress(struct alias_link *_lnk);
336 struct in_addr
337 GetDefaultAliasAddress(struct libalias *la);
338 void SetDefaultAliasAddress(struct libalias *la, struct in_addr _alias_addr);
339 u_short GetOriginalPort(struct alias_link *_lnk);
340 u_short GetAliasPort(struct alias_link *_lnk);
341 struct in_addr
342 GetProxyAddress(struct alias_link *_lnk);
343 void SetProxyAddress(struct alias_link *_lnk, struct in_addr _addr);
344 u_short GetProxyPort(struct alias_link *_lnk);
345 void SetProxyPort(struct alias_link *_lnk, u_short _port);
346 void SetAckModified(struct alias_link *_lnk);
347 int GetAckModified(struct alias_link *_lnk);
348 int GetDeltaAckIn(u_long, struct alias_link *_lnk);
349 int GetDeltaSeqOut(u_long, struct alias_link *lnk);
350 void AddSeq(struct alias_link *lnk, int delta, u_int ip_hl,
351 u_short ip_len, u_long th_seq, u_int th_off);
352 void SetExpire (struct alias_link *_lnk, int _expire);
353 void ClearCheckNewLink(struct libalias *la);
354 void SetProtocolFlags(struct alias_link *_lnk, int _pflags);
355 int GetProtocolFlags(struct alias_link *_lnk);
356 void SetDestCallId(struct alias_link *_lnk, u_int16_t _cid);
357
358 #ifndef NO_FW_PUNCH
359 void PunchFWHole(struct alias_link *_lnk);
360
361 #endif
362
363 /* Housekeeping function */
364 void HouseKeeping(struct libalias *);
365
366 /* Tcp specific routines */
367 /* lint -save -library Suppress flexelint warnings */
368
369 /* Transparent proxy routines */
370 int
371 ProxyCheck(struct libalias *la, struct in_addr *proxy_server_addr,
372 u_short * proxy_server_port, struct in_addr src_addr,
373 struct in_addr dst_addr, u_short dst_port, u_char ip_p);
374 void
375 ProxyModify(struct libalias *la, struct alias_link *_lnk, struct ip *_pip,
376 int _maxpacketsize, int _proxy_type);
377
378 enum alias_tcp_state {
379 ALIAS_TCP_STATE_NOT_CONNECTED,
380 ALIAS_TCP_STATE_CONNECTED,
381 ALIAS_TCP_STATE_DISCONNECTED
382 };
383
384 #if defined(_NETINET_IP_H_)
385 static __inline void *
ip_next(struct ip * iphdr)386 ip_next(struct ip *iphdr)
387 {
388 char *p = (char *)iphdr;
389 return (&p[iphdr->ip_hl * 4]);
390 }
391 #endif
392
393 #if defined(_NETINET_TCP_H_)
394 static __inline void *
tcp_next(struct tcphdr * tcphdr)395 tcp_next(struct tcphdr *tcphdr)
396 {
397 char *p = (char *)tcphdr;
398 return (&p[tcphdr->th_off * 4]);
399 }
400 #endif
401
402 #if defined(_NETINET_UDP_H_)
403 static __inline void *
udp_next(struct udphdr * udphdr)404 udp_next(struct udphdr *udphdr)
405 {
406 return ((void *)(udphdr + 1));
407 }
408 #endif
409
410 #endif /* !_ALIAS_LOCAL_H_ */
411