1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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
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/tree.h>
50 #include <sys/types.h>
51 #include <sys/sysctl.h>
52
53 #ifdef _KERNEL
54 #include <sys/malloc.h>
55 #include <sys/param.h>
56 #include <sys/lock.h>
57 #include <sys/mutex.h>
58
59 /* XXX: LibAliasSetTarget() uses this constant. */
60 #define INADDR_NONE 0xffffffff
61
62 #include <netinet/libalias/alias_sctp.h>
63 #else
64 #include "alias_sctp.h"
65 #endif
66
67 /* Sizes of input and output link tables */
68 #define GET_ALIAS_PORT -1
69 #define GET_ALIAS_ID GET_ALIAS_PORT
70
71 #ifdef _KERNEL
72 #define INET_NTOA_BUF(buf) (buf)
73 #else
74 #define INET_NTOA_BUF(buf) (buf), sizeof(buf)
75 #endif
76
77 struct proxy_entry;
78
79 struct group_in {
80 struct in_addr alias_addr;
81 u_short alias_port;
82 int link_type;
83 SPLAY_ENTRY(group_in) in;
84 LIST_HEAD(, alias_link) full, partial;
85 };
86
87 struct libalias {
88 LIST_ENTRY(libalias) instancelist;
89 /* Mode flags documented in alias.h */
90 int packetAliasMode;
91 /* Address written onto source field of IP packet. */
92 struct in_addr aliasAddress;
93 /* IP address incoming packets are sent to
94 * if no aliasing link already exists */
95 struct in_addr targetAddress;
96 /* Lookup table of pointers to chains of link records.
97 * Each link record is doubly indexed into input and
98 * output lookup tables. */
99 SPLAY_HEAD(splay_out, alias_link) linkSplayOut;
100 SPLAY_HEAD(splay_in, group_in) linkSplayIn;
101 LIST_HEAD (, alias_link) pptpList;
102 /* HouseKeeping */
103 TAILQ_HEAD (, alias_link) checkExpire;
104 /* Link statistics */
105 unsigned int icmpLinkCount;
106 unsigned int udpLinkCount;
107 unsigned int tcpLinkCount;
108 unsigned int pptpLinkCount;
109 unsigned int protoLinkCount;
110 unsigned int fragmentIdLinkCount;
111 unsigned int fragmentPtrLinkCount;
112 unsigned int sockCount;
113 /* log descriptor */
114 #ifdef _KERNEL
115 char *logDesc;
116 #else
117 FILE *logDesc;
118 #endif
119
120 #ifndef NO_FW_PUNCH
121 /* File descriptor to be able to control firewall.
122 * Opened by PacketAliasSetMode on first setting
123 * the PKT_ALIAS_PUNCH_FW flag. */
124 int fireWallFD;
125 /* The first firewall entry free for our use */
126 int fireWallBaseNum;
127 /* How many entries can we use? */
128 int fireWallNumNums;
129 /* Which entry did we last use? */
130 int fireWallActiveNum;
131 /* bool array for entries */
132 char *fireWallField;
133 #endif
134 /* TCP port used by the Skinny protocol. */
135 unsigned int skinnyPort;
136
137 struct proxy_entry *proxyList;
138
139 struct in_addr true_addr; /* in network byte order. */
140 u_short true_port; /* in host byte order. */
141
142 /* Port ranges for aliasing. */
143 u_short aliasPortLower;
144 u_short aliasPortLength;
145
146 /*
147 * sctp code support
148 */
149
150 /* counts associations that have progressed to UP and not yet removed */
151 int sctpLinkCount;
152 #ifdef _KERNEL
153 /* timing queue for keeping track of association timeouts */
154 struct sctp_nat_timer sctpNatTimer;
155 /* size of hash table used in this instance */
156 u_int sctpNatTableSize;
157 /* local look up table sorted by l_vtag/l_port */
158 LIST_HEAD(sctpNatTableL, sctp_nat_assoc) *sctpTableLocal;
159 /* global look up table sorted by g_vtag/g_port */
160 LIST_HEAD(sctpNatTableG, sctp_nat_assoc) *sctpTableGlobal;
161
162 /* avoid races in libalias: every public function has to use it. */
163 struct mtx mutex;
164 #endif
165 };
166
167 /* Macros */
168
169 #ifdef _KERNEL
170 #define LIBALIAS_LOCK_INIT(l) \
171 mtx_init(&l->mutex, "per-instance libalias mutex", NULL, MTX_DEF)
172 #define LIBALIAS_LOCK_ASSERT(l) mtx_assert(&l->mutex, MA_OWNED)
173 #define LIBALIAS_LOCK(l) mtx_lock(&l->mutex)
174 #define LIBALIAS_UNLOCK(l) mtx_unlock(&l->mutex)
175 #define LIBALIAS_LOCK_DESTROY(l) mtx_destroy(&l->mutex)
176 #else
177 #define LIBALIAS_LOCK_INIT(l)
178 #define LIBALIAS_LOCK_ASSERT(l)
179 #define LIBALIAS_LOCK(l)
180 #define LIBALIAS_UNLOCK(l)
181 #define LIBALIAS_LOCK_DESTROY(l)
182 #endif
183
184 /*
185 * The following macro is used to update an
186 * internet checksum. "delta" is a 32-bit
187 * accumulation of all the changes to the
188 * checksum (adding in new 16-bit words and
189 * subtracting out old words), and "cksum"
190 * is the checksum value to be updated.
191 */
192 #define ADJUST_CHECKSUM(acc, cksum) \
193 do { \
194 acc += cksum; \
195 if (acc < 0) { \
196 acc = -acc; \
197 acc = (acc >> 16) + (acc & 0xffff); \
198 acc += acc >> 16; \
199 cksum = (u_short) ~acc; \
200 } else { \
201 acc = (acc >> 16) + (acc & 0xffff); \
202 acc += acc >> 16; \
203 cksum = (u_short) acc; \
204 } \
205 } while (0)
206
207 /* Prototypes */
208
209 /* System time in seconds for current packet */
210 extern int LibAliasTime;
211
212 /*
213 * SctpFunction prototypes
214 *
215 */
216 void AliasSctpInit(struct libalias *la);
217 void AliasSctpTerm(struct libalias *la);
218 int SctpAlias(struct libalias *la, struct ip *ip, int direction);
219
220 /*
221 * We do not calculate TCP checksums when libalias is a kernel
222 * module, since it has no idea about checksum offloading.
223 * If TCP data has changed, then we just set checksum to zero,
224 * and caller must recalculate it himself.
225 * In case if libalias will edit UDP data, the same approach
226 * should be used.
227 */
228 #ifndef _KERNEL
229 u_short IpChecksum(struct ip *_pip);
230 u_short TcpChecksum(struct ip *_pip);
231 #endif
232 void
233 DifferentialChecksum(u_short * _cksum, void * _new, void * _old, int _n);
234
235 /* Internal data access */
236 struct alias_link *
237 AddLink(struct libalias *la, struct in_addr src_addr, struct in_addr dst_addr,
238 struct in_addr alias_addr, u_short src_port, u_short dst_port,
239 int alias_param, int link_type);
240 struct alias_link *
241 FindIcmpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
242 u_short _id_alias, int _create);
243 struct alias_link *
244 FindIcmpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
245 u_short _id, int _create);
246 struct alias_link *
247 FindFragmentIn1(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
248 u_short _ip_id);
249 struct alias_link *
250 FindFragmentIn2(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
251 u_short _ip_id);
252 struct alias_link *
253 AddFragmentPtrLink(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
254 struct alias_link *
255 FindFragmentPtr(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
256 struct alias_link *
257 FindProtoIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
258 u_char _proto);
259 struct alias_link *
260 FindProtoOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
261 u_char _proto);
262 struct alias_link *
263 FindUdpTcpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
264 u_short _dst_port, u_short _alias_port, u_char _proto, int _create);
265 struct alias_link *
266 FindUdpTcpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
267 u_short _src_port, u_short _dst_port, u_char _proto, int _create);
268 struct alias_link *
269 AddPptp(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
270 struct in_addr _alias_addr, u_int16_t _src_call_id);
271 struct alias_link *
272 FindPptpOutByCallId(struct libalias *la, struct in_addr _src_addr,
273 struct in_addr _dst_addr, u_int16_t _src_call_id);
274 struct alias_link *
275 FindPptpInByCallId(struct libalias *la, struct in_addr _dst_addr,
276 struct in_addr _alias_addr, u_int16_t _dst_call_id);
277 struct alias_link *
278 FindPptpOutByPeerCallId(struct libalias *la, struct in_addr _src_addr,
279 struct in_addr _dst_addr, u_int16_t _dst_call_id);
280 struct alias_link *
281 FindPptpInByPeerCallId(struct libalias *la, struct in_addr _dst_addr,
282 struct in_addr _alias_addr, u_int16_t _alias_call_id);
283 struct alias_link *
284 FindRtspOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
285 u_short _src_port, u_short _alias_port, u_char _proto);
286 struct in_addr
287 FindOriginalAddress(struct libalias *la, struct in_addr _alias_addr);
288 struct in_addr
289 FindAliasAddress(struct libalias *la, struct in_addr _original_addr);
290 struct in_addr
291 FindSctpRedirectAddress(struct libalias *la, struct sctp_nat_msg *sm);
292
293 /* External data access/modification */
294 int FindNewPortGroup(struct libalias *la, struct in_addr _dst_addr,
295 struct in_addr _alias_addr, u_short _src_port,
296 u_short _dst_port, u_short _port_count, u_char _proto,
297 u_char _align);
298 void GetFragmentAddr(struct alias_link *_lnk, struct in_addr *_src_addr);
299 void SetFragmentAddr(struct alias_link *_lnk, struct in_addr _src_addr);
300 void GetFragmentPtr(struct alias_link *_lnk, void **_fptr);
301 void SetFragmentPtr(struct alias_link *_lnk, void *fptr);
302 void SetStateIn(struct alias_link *_lnk, int _state);
303 void SetStateOut(struct alias_link *_lnk, int _state);
304 int GetStateIn (struct alias_link *_lnk);
305 int GetStateOut(struct alias_link *_lnk);
306 struct in_addr GetOriginalAddress(struct alias_link *_lnk);
307 struct in_addr GetDestAddress(struct alias_link *_lnk);
308 struct in_addr GetAliasAddress(struct alias_link *_lnk);
309 struct in_addr GetDefaultAliasAddress(struct libalias *la);
310 void SetDefaultAliasAddress(struct libalias *la, struct in_addr _alias_addr);
311 u_short GetOriginalPort(struct alias_link *_lnk);
312 u_short GetAliasPort(struct alias_link *_lnk);
313 struct in_addr GetProxyAddress(struct alias_link *_lnk);
314 void SetProxyAddress(struct alias_link *_lnk, struct in_addr _addr);
315 u_short GetProxyPort(struct alias_link *_lnk);
316 void SetProxyPort(struct alias_link *_lnk, u_short _port);
317 void SetAckModified(struct alias_link *_lnk);
318 int GetAckModified(struct alias_link *_lnk);
319 int GetDeltaAckIn(u_long, struct alias_link *_lnk);
320 int GetDeltaSeqOut(u_long, struct alias_link *lnk);
321 void AddSeq(struct alias_link *lnk, int delta, u_int ip_hl,
322 u_short ip_len, u_long th_seq, u_int th_off);
323 void SetExpire (struct alias_link *_lnk, int _expire);
324 void SetProtocolFlags(struct alias_link *_lnk, int _pflags);
325 int GetProtocolFlags(struct alias_link *_lnk);
326 void SetDestCallId(struct alias_link *_lnk, u_int16_t _cid);
327
328 #ifndef NO_FW_PUNCH
329 void PunchFWHole(struct alias_link *_lnk);
330
331 #endif
332
333 /* Housekeeping function */
334 void HouseKeeping(struct libalias *);
335
336 /* Transparent proxy routines */
337 int
338 ProxyCheck(struct libalias *la, struct in_addr *proxy_server_addr,
339 u_short * proxy_server_port, struct in_addr src_addr,
340 struct in_addr dst_addr, u_short dst_port, u_char ip_p);
341 void
342 ProxyModify(struct libalias *la, struct alias_link *_lnk, struct ip *_pip,
343 int _maxpacketsize, int _proxy_type);
344
345 /* Tcp specific routines */
346 /* lint -save -library Suppress flexelint warnings */
347
348 enum alias_tcp_state {
349 ALIAS_TCP_STATE_NOT_CONNECTED,
350 ALIAS_TCP_STATE_CONNECTED,
351 ALIAS_TCP_STATE_DISCONNECTED
352 };
353
354 #if defined(_NETINET_IP_H_)
355 static __inline void *
ip_next(struct ip * iphdr)356 ip_next(struct ip *iphdr)
357 {
358 char *p = (char *)iphdr;
359 return (&p[iphdr->ip_hl * 4]);
360 }
361 #endif
362
363 #if defined(_NETINET_TCP_H_)
364 static __inline void *
tcp_next(struct tcphdr * tcphdr)365 tcp_next(struct tcphdr *tcphdr)
366 {
367 char *p = (char *)tcphdr;
368 return (&p[tcphdr->th_off * 4]);
369 }
370 #endif
371
372 #if defined(_NETINET_UDP_H_)
373 static __inline void *
udp_next(struct udphdr * udphdr)374 udp_next(struct udphdr *udphdr)
375 {
376 return ((void *)(udphdr + 1));
377 }
378 #endif
379
380 #endif /* !_ALIAS_LOCAL_H_ */
381