sys/netinet/libalias/alias_local.h

   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 *
 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 *
 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 *
 376 udp_next(struct udphdr *udphdr)
 377 {
 378         return ((void *)(udphdr + 1));
 379 }
 380 #endif
 381
 382 #endif                          /* !_ALIAS_LOCAL_H_ */