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/* lint -save -library Flexelint comment for external headers */
/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2001 Charles Mott <cm@linktel.net>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Alias.h defines the outside world interfaces for the packet aliasing
* software.
*
* This software is placed into the public domain with no restrictions on its
* distribution.
*/
#ifndef _ALIAS_H_
#define _ALIAS_H_
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#define LIBALIAS_BUF_SIZE 128
#ifdef _KERNEL
/*
* The kernel version of libalias does not support these features.
*/
#define NO_FW_PUNCH
#define NO_USE_SOCKETS
#endif
/*
* The external interface to libalias, the packet aliasing engine.
*
* There are two sets of functions:
*
* PacketAlias*() the old API which doesn't take an instance pointer
* and therefore can only have one packet engine at a time.
*
* LibAlias*() the new API which takes as first argument a pointer to
* the instance of the packet aliasing engine.
*
* The functions otherwise correspond to each other one for one, except
* for the LibAliasUnaliasOut()/PacketUnaliasOut() function which were
* were misnamed in the old API.
*/
/*
* The instance structure
*/
struct libalias;
/*
* An anonymous structure, a pointer to which is returned from
* PacketAliasRedirectAddr(), PacketAliasRedirectPort() or
* PacketAliasRedirectProto(), passed to PacketAliasAddServer(),
* and freed by PacketAliasRedirectDelete().
*/
struct alias_link;
/* Initialization and control functions. */
struct libalias *LibAliasInit(struct libalias *);
void LibAliasSetAddress(struct libalias *, struct in_addr _addr);
void LibAliasSetAliasPortRange(struct libalias *la, u_short port_low, u_short port_hi);
void LibAliasSetFWBase(struct libalias *, unsigned int _base, unsigned int _num);
void LibAliasSetSkinnyPort(struct libalias *, unsigned int _port);
unsigned int LibAliasSetMode(struct libalias *, unsigned int _flags, unsigned int _mask);
void LibAliasUninit(struct libalias *);
/* Packet Handling functions. */
int LibAliasIn (struct libalias *, void *_ptr, int _maxpacketsize);
int LibAliasOut(struct libalias *, void *_ptr, int _maxpacketsize);
int LibAliasOutTry(struct libalias *, void *_ptr, int _maxpacketsize, int _create);
int LibAliasUnaliasOut(struct libalias *, void *_ptr, int _maxpacketsize);
/* Port and address redirection functions. */
int LibAliasAddServer(struct libalias *, struct alias_link *_lnk,
struct in_addr _addr, unsigned short _port);
struct alias_link * LibAliasRedirectAddr(struct libalias *, struct in_addr _src_addr,
struct in_addr _alias_addr);
int LibAliasRedirectDynamic(struct libalias *, struct alias_link *_lnk);
void LibAliasRedirectDelete(struct libalias *, struct alias_link *_lnk);
struct alias_link * LibAliasRedirectPort(struct libalias *, struct in_addr _src_addr,
unsigned short _src_port, struct in_addr _dst_addr,
unsigned short _dst_port, struct in_addr _alias_addr,
unsigned short _alias_port, unsigned char _proto);
struct alias_link * LibAliasRedirectProto(struct libalias *, struct in_addr _src_addr,
struct in_addr _dst_addr, struct in_addr _alias_addr,
unsigned char _proto);
/* Fragment Handling functions. */
void LibAliasFragmentIn(struct libalias *, void *_ptr, void *_ptr_fragment);
void *LibAliasGetFragment(struct libalias *, void *_ptr);
int LibAliasSaveFragment(struct libalias *, void *_ptr);
/* Miscellaneous functions. */
unsigned short LibAliasInternetChecksum(struct libalias *, unsigned short *_ptr, int _nbytes);
void LibAliasSetTarget(struct libalias *, struct in_addr _target_addr);
/* Transparent proxying routines. */
int LibAliasProxyRule(struct libalias *, const char *_cmd);
/* Module handling API */
int LibAliasLoadModule(char *);
int LibAliasUnLoadAllModule(void);
int LibAliasRefreshModules(void);
/* Mbuf helper function. */
struct mbuf *m_megapullup(struct mbuf *, int);
/*
* Mode flags and other constants.
*/
/* Mode flags, set using PacketAliasSetMode() */
/*
* If PKT_ALIAS_LOG is set, a message will be printed to /var/log/alias.log
* every time a link is created or deleted. This is useful for debugging.
*/
#define PKT_ALIAS_LOG 0x01
/*
* If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g. to ftp,
* telnet or web servers will be prevented by the aliasing mechanism.
*/
#define PKT_ALIAS_DENY_INCOMING 0x02
/*
* If PKT_ALIAS_SAME_PORTS is set, packets will be attempted sent from the
* same port as they originated on. This allows e.g. rsh to work *99% of the
* time*, but _not_ 100% (it will be slightly flakey instead of not working
* at all). This mode bit is set by PacketAliasInit(), so it is a default
* mode of operation.
*/
#define PKT_ALIAS_SAME_PORTS 0x04
/*
* If PKT_ALIAS_USE_SOCKETS is set, then when partially specified links (e.g.
* destination port and/or address is zero), the packet aliasing engine will
* attempt to allocate a socket for the aliasing port it chooses. This will
* avoid interference with the host machine. Fully specified links do not
* require this. This bit is set after a call to PacketAliasInit(), so it is
* a default mode of operation.
*/
#ifndef NO_USE_SOCKETS
#define PKT_ALIAS_USE_SOCKETS 0x08
#endif
/*-
* If PKT_ALIAS_UNREGISTERED_ONLY is set, then only packets with
* unregistered source addresses will be aliased. Private
* addresses are those in the following ranges:
*
* 10.0.0.0 -> 10.255.255.255
* 172.16.0.0 -> 172.31.255.255
* 192.168.0.0 -> 192.168.255.255
*/
#define PKT_ALIAS_UNREGISTERED_ONLY 0x10
/*
* If PKT_ALIAS_RESET_ON_ADDR_CHANGE is set, then the table of dynamic
* aliasing links will be reset whenever PacketAliasSetAddress() changes the
* default aliasing address. If the default aliasing address is left
* unchanged by this function call, then the table of dynamic aliasing links
* will be left intact. This bit is set after a call to PacketAliasInit().
*/
#define PKT_ALIAS_RESET_ON_ADDR_CHANGE 0x20
/*
* If PKT_ALIAS_PROXY_ONLY is set, then NAT will be disabled and only
* transparent proxying is performed.
*/
#define PKT_ALIAS_PROXY_ONLY 0x40
/*
* If PKT_ALIAS_REVERSE is set, the actions of PacketAliasIn() and
* PacketAliasOut() are reversed.
*/
#define PKT_ALIAS_REVERSE 0x80
#ifndef NO_FW_PUNCH
/*
* If PKT_ALIAS_PUNCH_FW is set, active FTP and IRC DCC connections will
* create a 'hole' in the firewall to allow the transfers to work. The
* ipfw rule number that the hole is created with is controlled by
* PacketAliasSetFWBase(). The hole will be attached to that
* particular alias_link, so when the link goes away the hole is deleted.
*/
#define PKT_ALIAS_PUNCH_FW 0x100
#endif
/*
* If PKT_ALIAS_SKIP_GLOBAL is set, nat instance is not checked for matching
* states in 'ipfw nat global' rule.
*/
#define PKT_ALIAS_SKIP_GLOBAL 0x200
/*
* Like PKT_ALIAS_UNREGISTERED_ONLY, but includes the RFC 6598
* (Carrier Grade NAT) address range as follows:
*
* 100.64.0.0 -> 100.127.255.255
*/
#define PKT_ALIAS_UNREGISTERED_CGN 0x400
/*
* When this bit is set, UDP uses endpoint-independent mapping (EIM), as per
* RFC 4787 ("full cone" NAT of RFC 3489). All packets from the same internal
* address:port are mapped to the same NAT address:port, regardless of their
* destination address:port. If filtering rules allow, and if
* PKT_ALIAS_DENY_INCOMING is unset, any other external address:port can also
* send to the internal address:port through its mapped NAT address:port. This
* is more compatible with applications, and can reduce the need for port
* forwarding, but less scalable as each NAT address:port can only be
* concurrently used by at most one internal address:port.
*
* When this bit is unset, UDP packets use endpoint-dependent mapping (EDM)
* ("symmetric" NAT). Each connection from a particular internal address:port
* to different external addresses:ports is mapped to a random and
* unpredictable NAT address:port. Two appplications behind EDM NATs can only
* connect to each other by port forwarding on the NAT, or tunnelling through
* an in-between server.
*/
#define PKT_ALIAS_UDP_EIM 0x800
/* Function return codes. */
#define PKT_ALIAS_ERROR -1
#define PKT_ALIAS_OK 1
#define PKT_ALIAS_IGNORED 2
#define PKT_ALIAS_UNRESOLVED_FRAGMENT 3
#define PKT_ALIAS_FOUND_HEADER_FRAGMENT 4
#endif /* !_ALIAS_H_ */
/* lint -restore */