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freebsd-nq/sys/netinet/libalias/alias_local.h
Paolo Pisati be4f3cd0d9 Summer of Code 2005: improve libalias - part 1 of 2 
With the first part of my previous Summer of Code work, we get:

-made libalias modular:

 -support for 'particular' protocols (like ftp/irc/etcetc) is no more
  hardcoded inside libalias, but it's available through external
  modules loadable at runtime

 -modules are available both in kernel (/boot/kernel/alias_*.ko) and
  user land (/lib/libalias_*)

 -protocols/applications modularized are: cuseeme, ftp, irc, nbt, pptp,
  skinny and smedia

-added logging support for kernel side

-cleanup

After a buildworld, do a 'mergemaster -i' to install the file libalias.conf
in /etc or manually copy it.

During startup (and after every HUP signal) user land applications running
the new libalias will try to read a file in /etc called libalias.conf:
that file contains the list of modules to load.

User land applications affected by this commit are ppp and natd:
if libalias.conf is present in /etc you won't notice any difference.

The only kernel land bit affected by this commit is ng_nat:
if you are using ng_nat, and it doesn't correctly handle
ftp/irc/etcetc sessions anymore, remember to kldload
the correspondent module (i.e. kldload alias_ftp).

General information and details about the inner working are available
in the libalias man page under the section 'MODULAR ARCHITECTURE
(AND ipfw(4) SUPPORT)'.

NOTA BENE: this commit affects _ONLY_ libalias, ipfw in-kernel nat
support will be part of the next libalias-related commit.

Approved by: glebius
Reviewed by: glebius, ru
2006-09-26 23:26:53 +00:00

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/*-
* 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.
*
* $FreeBSD$
*/
/*
* Alias_local.h contains the function prototypes for alias.c,
* alias_db.c, alias_util.c and alias_ftp.c, alias_irc.c (as well
* as any future add-ons). It also includes macros, globals and
* struct definitions shared by more than one alias*.c file.
*
* This include file is intended to be used only within the aliasing
* software. Outside world interfaces are defined in alias.h
*
* This software is placed into the public domain with no restrictions
* on its distribution.
*
* Initial version: August, 1996 (cjm)
*
* <updated several times by original author and Eivind Eklund>
*/
#ifndef _ALIAS_LOCAL_H_
#define _ALIAS_LOCAL_H_
#include <sys/types.h>
#include <sys/sysctl.h>
#ifdef _KERNEL
#include <sys/malloc.h>
#include <sys/lock.h>
/* XXX: LibAliasSetTarget() uses this constant. */
#define INADDR_NONE 0xffffffff
#endif
/* Sizes of input and output link tables */
#define LINK_TABLE_OUT_SIZE 101
#define LINK_TABLE_IN_SIZE 4001
struct proxy_entry;
struct libalias {
LIST_ENTRY(libalias) instancelist;
int packetAliasMode; /* Mode flags */
/* - documented in alias.h */
struct in_addr aliasAddress; /* Address written onto source */
/* field of IP packet. */
struct in_addr targetAddress; /* IP address incoming packets */
/* are sent to if no aliasing */
/* link already exists */
struct in_addr nullAddress; /* Used as a dummy parameter for */
/* some function calls */
LIST_HEAD (, alias_link) linkTableOut[LINK_TABLE_OUT_SIZE];
/* Lookup table of pointers to */
/* chains of link records. Each */
LIST_HEAD (, alias_link) linkTableIn[LINK_TABLE_IN_SIZE];
/* link record is doubly indexed */
/* into input and output lookup */
/* tables. */
/* Link statistics */
int icmpLinkCount;
int udpLinkCount;
int tcpLinkCount;
int pptpLinkCount;
int protoLinkCount;
int fragmentIdLinkCount;
int fragmentPtrLinkCount;
int sockCount;
int cleanupIndex; /* Index to chain of link table */
/* being inspected for old links */
int timeStamp; /* System time in seconds for */
/* current packet */
int lastCleanupTime; /* Last time
* IncrementalCleanup() */
/* was called */
int houseKeepingResidual; /* used by HouseKeeping() */
int deleteAllLinks; /* If equal to zero, DeleteLink() */
/* will not remove permanent links */
/* log descriptor */
#ifdef _KERNEL
char *logDesc;
#else
FILE *logDesc;
#endif
/* statistics monitoring */
int newDefaultLink; /* Indicates if a new aliasing */
/* link has been created after a */
/* call to PacketAliasIn/Out(). */
#ifndef NO_FW_PUNCH
int fireWallFD; /* File descriptor to be able to */
/* control firewall. Opened by */
/* PacketAliasSetMode on first */
/* setting the PKT_ALIAS_PUNCH_FW */
/* flag. */
int fireWallBaseNum; /* The first firewall entry
* free for our use */
int fireWallNumNums; /* How many entries can we
* use? */
int fireWallActiveNum; /* Which entry did we last
* use? */
char *fireWallField; /* bool array for entries */
#endif
unsigned int skinnyPort; /* TCP port used by the Skinny */
/* protocol. */
struct proxy_entry *proxyList;
struct in_addr true_addr; /* in network byte order. */
u_short true_port; /* in host byte order. */
};
/* Macros */
/*
* The following macro is used to update an
* internet checksum. "delta" is a 32-bit
* accumulation of all the changes to the
* checksum (adding in new 16-bit words and
* subtracting out old words), and "cksum"
* is the checksum value to be updated.
*/
#define ADJUST_CHECKSUM(acc, cksum) \
do { \
acc += cksum; \
if (acc < 0) { \
acc = -acc; \
acc = (acc >> 16) + (acc & 0xffff); \
acc += acc >> 16; \
cksum = (u_short) ~acc; \
} else { \
acc = (acc >> 16) + (acc & 0xffff); \
acc += acc >> 16; \
cksum = (u_short) acc; \
} \
} while (0)
/* Prototypes */
/*
* We do not calculate TCP checksums when libalias is a kernel
* module, since it has no idea about checksum offloading.
* If TCP data has changed, then we just set checksum to zero,
* and caller must recalculate it himself.
* In case if libalias will edit UDP data, the same approach
* should be used.
*/
#ifndef _KERNEL
u_short IpChecksum(struct ip *_pip);
u_short TcpChecksum(struct ip *_pip);
#endif
void
DifferentialChecksum(u_short * _cksum, void * _new, void * _old, int _n);
/* Internal data access */
struct alias_link *
FindIcmpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
u_short _id_alias, int _create);
struct alias_link *
FindIcmpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
u_short _id, int _create);
struct alias_link *
FindFragmentIn1(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
u_short _ip_id);
struct alias_link *
FindFragmentIn2(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
u_short _ip_id);
struct alias_link *
AddFragmentPtrLink(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
struct alias_link *
FindFragmentPtr(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
struct alias_link *
FindProtoIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
u_char _proto);
struct alias_link *
FindProtoOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
u_char _proto);
struct alias_link *
FindUdpTcpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
u_short _dst_port, u_short _alias_port, u_char _proto, int _create);
struct alias_link *
FindUdpTcpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
u_short _src_port, u_short _dst_port, u_char _proto, int _create);
struct alias_link *
AddPptp(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
struct in_addr _alias_addr, u_int16_t _src_call_id);
struct alias_link *
FindPptpOutByCallId(struct libalias *la, struct in_addr _src_addr,
struct in_addr _dst_addr, u_int16_t _src_call_id);
struct alias_link *
FindPptpInByCallId(struct libalias *la, struct in_addr _dst_addr,
struct in_addr _alias_addr, u_int16_t _dst_call_id);
struct alias_link *
FindPptpOutByPeerCallId(struct libalias *la, struct in_addr _src_addr,
struct in_addr _dst_addr, u_int16_t _dst_call_id);
struct alias_link *
FindPptpInByPeerCallId(struct libalias *la, struct in_addr _dst_addr,
struct in_addr _alias_addr, u_int16_t _alias_call_id);
struct alias_link *
FindRtspOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
u_short _src_port, u_short _alias_port, u_char _proto);
struct in_addr
FindOriginalAddress(struct libalias *la, struct in_addr _alias_addr);
struct in_addr
FindAliasAddress(struct libalias *la, struct in_addr _original_addr);
/* External data access/modification */
int
FindNewPortGroup(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
u_short _src_port, u_short _dst_port, u_short _port_count,
u_char _proto, u_char _align);
void GetFragmentAddr(struct alias_link *_lnk, struct in_addr *_src_addr);
void SetFragmentAddr(struct alias_link *_lnk, struct in_addr _src_addr);
void GetFragmentPtr(struct alias_link *_lnk, char **_fptr);
void SetFragmentPtr(struct alias_link *_lnk, char *fptr);
void SetStateIn(struct alias_link *_lnk, int _state);
void SetStateOut(struct alias_link *_lnk, int _state);
int GetStateIn (struct alias_link *_lnk);
int GetStateOut(struct alias_link *_lnk);
struct in_addr
GetOriginalAddress(struct alias_link *_lnk);
struct in_addr
GetDestAddress(struct alias_link *_lnk);
struct in_addr
GetAliasAddress(struct alias_link *_lnk);
struct in_addr
GetDefaultAliasAddress(struct libalias *la);
void SetDefaultAliasAddress(struct libalias *la, struct in_addr _alias_addr);
u_short GetOriginalPort(struct alias_link *_lnk);
u_short GetAliasPort(struct alias_link *_lnk);
struct in_addr
GetProxyAddress(struct alias_link *_lnk);
void SetProxyAddress(struct alias_link *_lnk, struct in_addr _addr);
u_short GetProxyPort(struct alias_link *_lnk);
void SetProxyPort(struct alias_link *_lnk, u_short _port);
void SetAckModified(struct alias_link *_lnk);
int GetAckModified(struct alias_link *_lnk);
int GetDeltaAckIn(struct ip *_pip, struct alias_link *_lnk);
int GetDeltaSeqOut(struct ip *_pip, struct alias_link *_lnk);
void AddSeq (struct ip *_pip, struct alias_link *_lnk, int _delta);
void SetExpire (struct alias_link *_lnk, int _expire);
void ClearCheckNewLink(struct libalias *la);
void SetProtocolFlags(struct alias_link *_lnk, int _pflags);
int GetProtocolFlags(struct alias_link *_lnk);
void SetDestCallId(struct alias_link *_lnk, u_int16_t _cid);
#ifndef NO_FW_PUNCH
void PunchFWHole(struct alias_link *_lnk);
#endif
/* Housekeeping function */
void HouseKeeping(struct libalias *);
/* Tcp specfic routines */
/* lint -save -library Suppress flexelint warnings */
/* Transparent proxy routines */
int
ProxyCheck(struct libalias *la, struct ip *_pip, struct in_addr *_proxy_server_addr,
u_short * _proxy_server_port);
void
ProxyModify(struct libalias *la, struct alias_link *_lnk, struct ip *_pip,
int _maxpacketsize, int _proxy_type);
enum alias_tcp_state {
ALIAS_TCP_STATE_NOT_CONNECTED,
ALIAS_TCP_STATE_CONNECTED,
ALIAS_TCP_STATE_DISCONNECTED
};
#if defined(_NETINET_IP_H_)
static __inline void *
ip_next(struct ip *iphdr)
{
char *p = (char *)iphdr;
return (&p[iphdr->ip_hl * 4]);
}
#endif
#if defined(_NETINET_TCP_H_)
static __inline void *
tcp_next(struct tcphdr *tcphdr)
{
char *p = (char *)tcphdr;
return (&p[tcphdr->th_off * 4]);
}
#endif
#if defined(_NETINET_UDP_H_)
static __inline void *
udp_next(struct udphdr *udphdr)
{
return ((void *)(udphdr + 1));
}
#endif
#endif /* !_ALIAS_LOCAL_H_ */
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