d261e57dea
Current data structure is using a hash of unordered lists. Those unordered lists are quite efficient, because the least recently inserted entries are most likely to be used again. In order to avoid long search times in other cases, the lists are hashed into many buckets. Unfortunatly a search for a miss needs an exhaustive inspection and a careful definition of the hash. Splay trees offer a similar feature: Almost O(1) for access of the least recently used entries, and amortized O(ln(n)) for almost all other cases. Get rid of the hash. Now the data structure should able to quickly react to external packets without eating CPU cycles for breakfast, preventing a DoS. PR: 192888 Discussed with: Dimitry Luhtionov MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D30536
383 lines
13 KiB
C
383 lines
13 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2001 Charles Mott <cm@linktel.net>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* Alias_local.h contains the function prototypes for alias.c,
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* alias_db.c, alias_util.c and alias_ftp.c, alias_irc.c (as well
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* as any future add-ons). It also includes macros, globals and
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* struct definitions shared by more than one alias*.c file.
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*
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* This include file is intended to be used only within the aliasing
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* software. Outside world interfaces are defined in alias.h
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*
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* This software is placed into the public domain with no restrictions
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* on its distribution.
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*
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* Initial version: August, 1996 (cjm)
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*
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* <updated several times by original author and Eivind Eklund>
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*/
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#ifndef _ALIAS_LOCAL_H_
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#define _ALIAS_LOCAL_H_
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#include <sys/tree.h>
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#include <sys/types.h>
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#include <sys/sysctl.h>
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#ifdef _KERNEL
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#include <sys/malloc.h>
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#include <sys/param.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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/* XXX: LibAliasSetTarget() uses this constant. */
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#define INADDR_NONE 0xffffffff
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#include <netinet/libalias/alias_sctp.h>
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#else
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#include "alias_sctp.h"
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#endif
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/* Sizes of input and output link tables */
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#define GET_ALIAS_PORT -1
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#define GET_ALIAS_ID GET_ALIAS_PORT
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#ifdef _KERNEL
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#define INET_NTOA_BUF(buf) (buf)
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#else
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#define INET_NTOA_BUF(buf) (buf), sizeof(buf)
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#endif
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struct proxy_entry;
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struct group_in {
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struct in_addr alias_addr;
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u_short alias_port;
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int link_type;
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SPLAY_ENTRY(group_in) in;
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LIST_HEAD(, alias_link) full, partial;
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};
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struct libalias {
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LIST_ENTRY(libalias) instancelist;
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/* Mode flags documented in alias.h */
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int packetAliasMode;
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/* Address written onto source field of IP packet. */
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struct in_addr aliasAddress;
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/* IP address incoming packets are sent to
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* if no aliasing link already exists */
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struct in_addr targetAddress;
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/* Lookup table of pointers to chains of link records.
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* Each link record is doubly indexed into input and
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* output lookup tables. */
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SPLAY_HEAD(splay_out, alias_link) linkSplayOut;
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SPLAY_HEAD(splay_in, group_in) linkSplayIn;
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LIST_HEAD (, alias_link) pptpList;
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/* HouseKeeping */
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TAILQ_HEAD (, alias_link) checkExpire;
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/* Link statistics */
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unsigned int icmpLinkCount;
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unsigned int udpLinkCount;
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unsigned int tcpLinkCount;
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unsigned int pptpLinkCount;
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unsigned int protoLinkCount;
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unsigned int fragmentIdLinkCount;
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unsigned int fragmentPtrLinkCount;
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unsigned int sockCount;
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/* log descriptor */
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#ifdef _KERNEL
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char *logDesc;
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#else
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FILE *logDesc;
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#endif
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#ifndef NO_FW_PUNCH
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/* File descriptor to be able to control firewall.
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* Opened by PacketAliasSetMode on first setting
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* the PKT_ALIAS_PUNCH_FW flag. */
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int fireWallFD;
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/* The first firewall entry free for our use */
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int fireWallBaseNum;
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/* How many entries can we use? */
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int fireWallNumNums;
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/* Which entry did we last use? */
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int fireWallActiveNum;
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/* bool array for entries */
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char *fireWallField;
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#endif
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/* TCP port used by the Skinny protocol. */
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unsigned int skinnyPort;
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struct proxy_entry *proxyList;
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struct in_addr true_addr; /* in network byte order. */
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u_short true_port; /* in host byte order. */
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/* Port ranges for aliasing. */
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u_short aliasPortLower;
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u_short aliasPortLength;
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/*
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* sctp code support
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*/
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/* counts associations that have progressed to UP and not yet removed */
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int sctpLinkCount;
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#ifdef _KERNEL
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/* timing queue for keeping track of association timeouts */
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struct sctp_nat_timer sctpNatTimer;
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/* size of hash table used in this instance */
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u_int sctpNatTableSize;
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/* local look up table sorted by l_vtag/l_port */
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LIST_HEAD(sctpNatTableL, sctp_nat_assoc) *sctpTableLocal;
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/* global look up table sorted by g_vtag/g_port */
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LIST_HEAD(sctpNatTableG, sctp_nat_assoc) *sctpTableGlobal;
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/* avoid races in libalias: every public function has to use it. */
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struct mtx mutex;
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#endif
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};
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/* Macros */
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#ifdef _KERNEL
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#define LIBALIAS_LOCK_INIT(l) \
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mtx_init(&l->mutex, "per-instance libalias mutex", NULL, MTX_DEF)
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#define LIBALIAS_LOCK_ASSERT(l) mtx_assert(&l->mutex, MA_OWNED)
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#define LIBALIAS_LOCK(l) mtx_lock(&l->mutex)
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#define LIBALIAS_UNLOCK(l) mtx_unlock(&l->mutex)
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#define LIBALIAS_LOCK_DESTROY(l) mtx_destroy(&l->mutex)
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#else
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#define LIBALIAS_LOCK_INIT(l)
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#define LIBALIAS_LOCK_ASSERT(l)
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#define LIBALIAS_LOCK(l)
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#define LIBALIAS_UNLOCK(l)
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#define LIBALIAS_LOCK_DESTROY(l)
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#endif
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/*
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* The following macro is used to update an
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* internet checksum. "delta" is a 32-bit
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* accumulation of all the changes to the
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* checksum (adding in new 16-bit words and
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* subtracting out old words), and "cksum"
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* is the checksum value to be updated.
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*/
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#define ADJUST_CHECKSUM(acc, cksum) \
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do { \
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acc += cksum; \
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if (acc < 0) { \
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acc = -acc; \
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acc = (acc >> 16) + (acc & 0xffff); \
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acc += acc >> 16; \
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cksum = (u_short) ~acc; \
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} else { \
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acc = (acc >> 16) + (acc & 0xffff); \
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acc += acc >> 16; \
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cksum = (u_short) acc; \
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} \
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} while (0)
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/* Prototypes */
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/* System time in seconds for current packet */
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extern int LibAliasTime;
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/*
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* SctpFunction prototypes
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*
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*/
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void AliasSctpInit(struct libalias *la);
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void AliasSctpTerm(struct libalias *la);
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int SctpAlias(struct libalias *la, struct ip *ip, int direction);
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/*
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* We do not calculate TCP checksums when libalias is a kernel
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* module, since it has no idea about checksum offloading.
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* If TCP data has changed, then we just set checksum to zero,
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* and caller must recalculate it himself.
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* In case if libalias will edit UDP data, the same approach
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* should be used.
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*/
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#ifndef _KERNEL
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u_short IpChecksum(struct ip *_pip);
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u_short TcpChecksum(struct ip *_pip);
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#endif
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void
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DifferentialChecksum(u_short * _cksum, void * _new, void * _old, int _n);
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/* Internal data access */
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struct alias_link *
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AddLink(struct libalias *la, struct in_addr src_addr, struct in_addr dst_addr,
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struct in_addr alias_addr, u_short src_port, u_short dst_port,
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int alias_param, int link_type);
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struct alias_link *
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FindIcmpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
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u_short _id_alias, int _create);
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struct alias_link *
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FindIcmpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
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u_short _id, int _create);
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struct alias_link *
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FindFragmentIn1(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
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u_short _ip_id);
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struct alias_link *
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FindFragmentIn2(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
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u_short _ip_id);
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struct alias_link *
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AddFragmentPtrLink(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
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struct alias_link *
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FindFragmentPtr(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
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struct alias_link *
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FindProtoIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
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u_char _proto);
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struct alias_link *
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FindProtoOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
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u_char _proto);
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struct alias_link *
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FindUdpTcpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
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u_short _dst_port, u_short _alias_port, u_char _proto, int _create);
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struct alias_link *
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FindUdpTcpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
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u_short _src_port, u_short _dst_port, u_char _proto, int _create);
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struct alias_link *
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AddPptp(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
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struct in_addr _alias_addr, u_int16_t _src_call_id);
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struct alias_link *
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FindPptpOutByCallId(struct libalias *la, struct in_addr _src_addr,
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struct in_addr _dst_addr, u_int16_t _src_call_id);
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struct alias_link *
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FindPptpInByCallId(struct libalias *la, struct in_addr _dst_addr,
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struct in_addr _alias_addr, u_int16_t _dst_call_id);
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struct alias_link *
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FindPptpOutByPeerCallId(struct libalias *la, struct in_addr _src_addr,
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struct in_addr _dst_addr, u_int16_t _dst_call_id);
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struct alias_link *
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FindPptpInByPeerCallId(struct libalias *la, struct in_addr _dst_addr,
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struct in_addr _alias_addr, u_int16_t _alias_call_id);
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struct alias_link *
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FindRtspOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
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u_short _src_port, u_short _alias_port, u_char _proto);
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struct in_addr
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FindOriginalAddress(struct libalias *la, struct in_addr _alias_addr);
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struct in_addr
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FindAliasAddress(struct libalias *la, struct in_addr _original_addr);
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struct in_addr
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FindSctpRedirectAddress(struct libalias *la, struct sctp_nat_msg *sm);
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/* External data access/modification */
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int FindNewPortGroup(struct libalias *la, struct in_addr _dst_addr,
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struct in_addr _alias_addr, u_short _src_port,
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u_short _dst_port, u_short _port_count, u_char _proto,
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u_char _align);
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void GetFragmentAddr(struct alias_link *_lnk, struct in_addr *_src_addr);
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void SetFragmentAddr(struct alias_link *_lnk, struct in_addr _src_addr);
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void GetFragmentPtr(struct alias_link *_lnk, void **_fptr);
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void SetFragmentPtr(struct alias_link *_lnk, void *fptr);
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void SetStateIn(struct alias_link *_lnk, int _state);
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void SetStateOut(struct alias_link *_lnk, int _state);
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int GetStateIn (struct alias_link *_lnk);
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int GetStateOut(struct alias_link *_lnk);
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struct in_addr GetOriginalAddress(struct alias_link *_lnk);
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struct in_addr GetDestAddress(struct alias_link *_lnk);
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struct in_addr GetAliasAddress(struct alias_link *_lnk);
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struct in_addr GetDefaultAliasAddress(struct libalias *la);
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void SetDefaultAliasAddress(struct libalias *la, struct in_addr _alias_addr);
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u_short GetOriginalPort(struct alias_link *_lnk);
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u_short GetAliasPort(struct alias_link *_lnk);
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struct in_addr GetProxyAddress(struct alias_link *_lnk);
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void SetProxyAddress(struct alias_link *_lnk, struct in_addr _addr);
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u_short GetProxyPort(struct alias_link *_lnk);
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void SetProxyPort(struct alias_link *_lnk, u_short _port);
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void SetAckModified(struct alias_link *_lnk);
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int GetAckModified(struct alias_link *_lnk);
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int GetDeltaAckIn(u_long, struct alias_link *_lnk);
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int GetDeltaSeqOut(u_long, struct alias_link *lnk);
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void AddSeq(struct alias_link *lnk, int delta, u_int ip_hl,
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u_short ip_len, u_long th_seq, u_int th_off);
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void SetExpire (struct alias_link *_lnk, int _expire);
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void SetProtocolFlags(struct alias_link *_lnk, int _pflags);
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int GetProtocolFlags(struct alias_link *_lnk);
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void SetDestCallId(struct alias_link *_lnk, u_int16_t _cid);
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#ifndef NO_FW_PUNCH
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void PunchFWHole(struct alias_link *_lnk);
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#endif
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/* Housekeeping function */
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void HouseKeeping(struct libalias *);
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/* Transparent proxy routines */
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int
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ProxyCheck(struct libalias *la, struct in_addr *proxy_server_addr,
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u_short * proxy_server_port, struct in_addr src_addr,
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struct in_addr dst_addr, u_short dst_port, u_char ip_p);
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void
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ProxyModify(struct libalias *la, struct alias_link *_lnk, struct ip *_pip,
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int _maxpacketsize, int _proxy_type);
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/* Tcp specific routines */
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/* lint -save -library Suppress flexelint warnings */
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enum alias_tcp_state {
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ALIAS_TCP_STATE_NOT_CONNECTED,
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ALIAS_TCP_STATE_CONNECTED,
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ALIAS_TCP_STATE_DISCONNECTED
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};
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#if defined(_NETINET_IP_H_)
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static __inline void *
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ip_next(struct ip *iphdr)
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{
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char *p = (char *)iphdr;
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return (&p[iphdr->ip_hl * 4]);
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}
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#endif
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#if defined(_NETINET_TCP_H_)
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static __inline void *
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tcp_next(struct tcphdr *tcphdr)
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{
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char *p = (char *)tcphdr;
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return (&p[tcphdr->th_off * 4]);
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}
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#endif
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#if defined(_NETINET_UDP_H_)
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static __inline void *
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udp_next(struct udphdr *udphdr)
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{
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return ((void *)(udphdr + 1));
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}
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#endif
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#endif /* !_ALIAS_LOCAL_H_ */
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