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 indexed into input,
98 * output and "internal endpoint" lookup tables. */
99 SPLAY_HEAD(splay_out, alias_link) linkSplayOut;
100 SPLAY_HEAD(splay_in, group_in) linkSplayIn;
101 SPLAY_HEAD(splay_internal_endpoint, alias_link)
102 linkSplayInternalEndpoint;
103 LIST_HEAD (, alias_link) pptpList;
104 /* HouseKeeping */
105 TAILQ_HEAD (, alias_link) checkExpire;
106 /* Link statistics */
107 unsigned int icmpLinkCount;
108 unsigned int udpLinkCount;
109 unsigned int tcpLinkCount;
110 unsigned int pptpLinkCount;
111 unsigned int protoLinkCount;
112 unsigned int fragmentIdLinkCount;
113 unsigned int fragmentPtrLinkCount;
114 unsigned int sockCount;
115 /* log descriptor */
116 #ifdef _KERNEL
117 char *logDesc;
118 #else
119 FILE *logDesc;
120 #endif
121
122 #ifndef NO_FW_PUNCH
123 /* File descriptor to be able to control firewall.
124 * Opened by PacketAliasSetMode on first setting
125 * the PKT_ALIAS_PUNCH_FW flag. */
126 int fireWallFD;
127 /* The first firewall entry free for our use */
128 int fireWallBaseNum;
129 /* How many entries can we use? */
130 int fireWallNumNums;
131 /* Which entry did we last use? */
132 int fireWallActiveNum;
133 /* bool array for entries */
134 char *fireWallField;
135 #endif
136 /* TCP port used by the Skinny protocol. */
137 unsigned int skinnyPort;
138
139 struct proxy_entry *proxyList;
140
141 struct in_addr true_addr; /* in network byte order. */
142 u_short true_port; /* in host byte order. */
143
144 /* Port ranges for aliasing. */
145 u_short aliasPortLower;
146 u_short aliasPortLength;
147
148 /*
149 * sctp code support
150 */
151
152 /* counts associations that have progressed to UP and not yet removed */
153 int sctpLinkCount;
154 #ifdef _KERNEL
155 /* timing queue for keeping track of association timeouts */
156 struct sctp_nat_timer sctpNatTimer;
157 /* size of hash table used in this instance */
158 u_int sctpNatTableSize;
159 /* local look up table sorted by l_vtag/l_port */
160 LIST_HEAD(sctpNatTableL, sctp_nat_assoc) *sctpTableLocal;
161 /* global look up table sorted by g_vtag/g_port */
162 LIST_HEAD(sctpNatTableG, sctp_nat_assoc) *sctpTableGlobal;
163
164 /* avoid races in libalias: every public function has to use it. */
165 struct mtx mutex;
166 #endif
167 };
168
169 /* Macros */
170
171 #ifdef _KERNEL
172 #define LIBALIAS_LOCK_INIT(l) \
173 mtx_init(&l->mutex, "per-instance libalias mutex", NULL, MTX_DEF)
174 #define LIBALIAS_LOCK_ASSERT(l) mtx_assert(&l->mutex, MA_OWNED)
175 #define LIBALIAS_LOCK(l) mtx_lock(&l->mutex)
176 #define LIBALIAS_UNLOCK(l) mtx_unlock(&l->mutex)
177 #define LIBALIAS_LOCK_DESTROY(l) mtx_destroy(&l->mutex)
178 #else
179 #define LIBALIAS_LOCK_INIT(l)
180 #define LIBALIAS_LOCK_ASSERT(l)
181 #define LIBALIAS_LOCK(l)
182 #define LIBALIAS_UNLOCK(l)
183 #define LIBALIAS_LOCK_DESTROY(l)
184 #endif
185
186 /*
187 * The following macro is used to update an
188 * internet checksum. "delta" is a 32-bit
189 * accumulation of all the changes to the
190 * checksum (adding in new 16-bit words and
191 * subtracting out old words), and "cksum"
192 * is the checksum value to be updated.
193 */
194 #define ADJUST_CHECKSUM(acc, cksum) \
195 do { \
196 acc += cksum; \
197 if (acc < 0) { \
198 acc = -acc; \
199 acc = (acc >> 16) + (acc & 0xffff); \
200 acc += acc >> 16; \
201 cksum = (u_short) ~acc; \
202 } else { \
203 acc = (acc >> 16) + (acc & 0xffff); \
204 acc += acc >> 16; \
205 cksum = (u_short) acc; \
206 } \
207 } while (0)
208
209 /* Prototypes */
210
211 /* System time in seconds for current packet */
212 extern int LibAliasTime;
213
214 /*
215 * SctpFunction prototypes
216 *
217 */
218 void AliasSctpInit(struct libalias *la);
219 void AliasSctpTerm(struct libalias *la);
220 int SctpAlias(struct libalias *la, struct ip *ip, int direction);
221
222 /*
223 * We do not calculate TCP checksums when libalias is a kernel
224 * module, since it has no idea about checksum offloading.
225 * If TCP data has changed, then we just set checksum to zero,
226 * and caller must recalculate it himself.
227 * In case if libalias will edit UDP data, the same approach
228 * should be used.
229 */
230 #ifndef _KERNEL
231 u_short IpChecksum(struct ip *_pip);
232 u_short TcpChecksum(struct ip *_pip);
233 #endif
234 void
235 DifferentialChecksum(u_short * _cksum, void * _new, void * _old, int _n);
236
237 /* Internal data access */
238 struct alias_link *
239 AddLink(struct libalias *la, struct in_addr src_addr, struct in_addr dst_addr,
240 struct in_addr alias_addr, u_short src_port, u_short dst_port,
241 int alias_param, int link_type);
242 struct alias_link *
243 FindIcmpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
244 u_short _id_alias, int _create);
245 struct alias_link *
246 FindIcmpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
247 u_short _id, int _create);
248 struct alias_link *
249 FindFragmentIn1(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
250 u_short _ip_id);
251 struct alias_link *
252 FindFragmentIn2(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
253 u_short _ip_id);
254 struct alias_link *
255 AddFragmentPtrLink(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
256 struct alias_link *
257 FindFragmentPtr(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
258 struct alias_link *
259 FindProtoIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
260 u_char _proto);
261 struct alias_link *
262 FindProtoOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
263 u_char _proto);
264 struct alias_link *
265 FindUdpTcpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
266 u_short _dst_port, u_short _alias_port, u_char _proto, int _create);
267 struct alias_link *
268 FindUdpTcpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
269 u_short _src_port, u_short _dst_port, u_char _proto, int _create);
270 struct alias_link *
271 AddPptp(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
272 struct in_addr _alias_addr, u_int16_t _src_call_id);
273 struct alias_link *
274 FindPptpOutByCallId(struct libalias *la, struct in_addr _src_addr,
275 struct in_addr _dst_addr, u_int16_t _src_call_id);
276 struct alias_link *
277 FindPptpInByCallId(struct libalias *la, struct in_addr _dst_addr,
278 struct in_addr _alias_addr, u_int16_t _dst_call_id);
279 struct alias_link *
280 FindPptpOutByPeerCallId(struct libalias *la, struct in_addr _src_addr,
281 struct in_addr _dst_addr, u_int16_t _dst_call_id);
282 struct alias_link *
283 FindPptpInByPeerCallId(struct libalias *la, struct in_addr _dst_addr,
284 struct in_addr _alias_addr, u_int16_t _alias_call_id);
285 struct alias_link *
286 FindRtspOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
287 u_short _src_port, u_short _alias_port, u_char _proto);
288 struct in_addr
289 FindOriginalAddress(struct libalias *la, struct in_addr _alias_addr);
290 struct in_addr
291 FindAliasAddress(struct libalias *la, struct in_addr _original_addr);
292 struct in_addr
293 FindSctpRedirectAddress(struct libalias *la, struct sctp_nat_msg *sm);
294
295 /* External data access/modification */
296 int FindNewPortGroup(struct libalias *la, struct in_addr _dst_addr,
297 struct in_addr _alias_addr, u_short _src_port,
298 u_short _dst_port, u_short _port_count, u_char _proto,
299 u_char _align);
300 void GetFragmentAddr(struct alias_link *_lnk, struct in_addr *_src_addr);
301 void SetFragmentAddr(struct alias_link *_lnk, struct in_addr _src_addr);
302 void GetFragmentPtr(struct alias_link *_lnk, void **_fptr);
303 void SetFragmentPtr(struct alias_link *_lnk, void *fptr);
304 void SetStateIn(struct alias_link *_lnk, int _state);
305 void SetStateOut(struct alias_link *_lnk, int _state);
306 int GetStateIn (struct alias_link *_lnk);
307 int GetStateOut(struct alias_link *_lnk);
308 struct in_addr GetOriginalAddress(struct alias_link *_lnk);
309 struct in_addr GetDestAddress(struct alias_link *_lnk);
310 struct in_addr GetAliasAddress(struct alias_link *_lnk);
311 struct in_addr GetDefaultAliasAddress(struct libalias *la);
312 void SetDefaultAliasAddress(struct libalias *la, struct in_addr _alias_addr);
313 u_short GetOriginalPort(struct alias_link *_lnk);
314 u_short GetAliasPort(struct alias_link *_lnk);
315 struct in_addr GetProxyAddress(struct alias_link *_lnk);
316 void SetProxyAddress(struct alias_link *_lnk, struct in_addr _addr);
317 u_short GetProxyPort(struct alias_link *_lnk);
318 void SetProxyPort(struct alias_link *_lnk, u_short _port);
319 void SetAckModified(struct alias_link *_lnk);
320 int GetAckModified(struct alias_link *_lnk);
321 int GetDeltaAckIn(u_long, struct alias_link *_lnk);
322 int GetDeltaSeqOut(u_long, struct alias_link *lnk);
323 void AddSeq(struct alias_link *lnk, int delta, u_int ip_hl,
324 u_short ip_len, u_long th_seq, u_int th_off);
325 void SetExpire (struct alias_link *_lnk, int _expire);
326 void SetProtocolFlags(struct alias_link *_lnk, int _pflags);
327 int GetProtocolFlags(struct alias_link *_lnk);
328 void SetDestCallId(struct alias_link *_lnk, u_int16_t _cid);
329
330 #ifndef NO_FW_PUNCH
331 void PunchFWHole(struct alias_link *_lnk);
332
333 #endif
334
335 /* Housekeeping function */
336 void HouseKeeping(struct libalias *);
337
338 /* Transparent proxy routines */
339 int
340 ProxyCheck(struct libalias *la, struct in_addr *proxy_server_addr,
341 u_short * proxy_server_port, struct in_addr src_addr,
342 struct in_addr dst_addr, u_short dst_port, u_char ip_p);
343 void
344 ProxyModify(struct libalias *la, struct alias_link *_lnk, struct ip *_pip,
345 int _maxpacketsize, int _proxy_type);
346
347 /* Tcp specific routines */
348 /* lint -save -library Suppress flexelint warnings */
349
350 enum alias_tcp_state {
351 ALIAS_TCP_STATE_NOT_CONNECTED,
352 ALIAS_TCP_STATE_CONNECTED,
353 ALIAS_TCP_STATE_DISCONNECTED
354 };
355
356 #if defined(_NETINET_IP_H_)
357 static __inline void *
ip_next(struct ip * iphdr)358 ip_next(struct ip *iphdr)
359 {
360 char *p = (char *)iphdr;
361 return (&p[iphdr->ip_hl * 4]);
362 }
363 #endif
364
365 #if defined(_NETINET_TCP_H_)
366 static __inline void *
tcp_next(struct tcphdr * tcphdr)367 tcp_next(struct tcphdr *tcphdr)
368 {
369 char *p = (char *)tcphdr;
370 return (&p[tcphdr->th_off * 4]);
371 }
372 #endif
373
374 #if defined(_NETINET_UDP_H_)
375 static __inline void *
udp_next(struct udphdr * udphdr)376 udp_next(struct udphdr *udphdr)
377 {
378 return ((void *)(udphdr + 1));
379 }
380 #endif
381
382 #endif /* !_ALIAS_LOCAL_H_ */
383