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freebsd-skq/sys/netinet/libalias/alias_db.c
Lutz Donnerhacke 189f8eea13 libalias: replace placeholder with static constant 
The field nullAddress in struct libalias is never set and never used.
It exists as a placeholder for an unused argument only.

Reviewed by:	hselasky
MFC after:	2 weeks
Differential Revision: https://reviews.freebsd.org/D30253
2021-05-15 09:05:30 +02:00

2855 lines
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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
Alias_db.c encapsulates all data structures used for storing
packet aliasing data. Other parts of the aliasing software
access data through functions provided in this file.
Data storage is based on the notion of a "link", which is
established for ICMP echo/reply packets, UDP datagrams and
TCP stream connections. A link stores the original source
and destination addresses. For UDP and TCP, it also stores
source and destination port numbers, as well as an alias
port number. Links are also used to store information about
fragments.
There is a facility for sweeping through and deleting old
links as new packets are sent through. A simple timeout is
used for ICMP and UDP links. TCP links are left alone unless
there is an incomplete connection, in which case the link
can be deleted after a certain amount of time.
Initial version: August, 1996 (cjm)
Version 1.4: September 16, 1996 (cjm)
Facility for handling incoming links added.
Version 1.6: September 18, 1996 (cjm)
ICMP data handling simplified.
Version 1.7: January 9, 1997 (cjm)
Fragment handling simplified.
Saves pointers for unresolved fragments.
Permits links for unspecified remote ports
or unspecified remote addresses.
Fixed bug which did not properly zero port
table entries after a link was deleted.
Cleaned up some obsolete comments.
Version 1.8: January 14, 1997 (cjm)
Fixed data type error in StartPoint().
(This error did not exist prior to v1.7
and was discovered and fixed by Ari Suutari)
Version 1.9: February 1, 1997
Optionally, connections initiated from packet aliasing host
machine will will not have their port number aliased unless it
conflicts with an aliasing port already being used. (cjm)
All options earlier being #ifdef'ed are now available through
a new interface, SetPacketAliasMode(). This allows run time
control (which is now available in PPP+pktAlias through the
'alias' keyword). (ee)
Added ability to create an alias port without
either destination address or port specified.
port type = ALIAS_PORT_UNKNOWN_DEST_ALL (ee)
Removed K&R style function headers
and general cleanup. (ee)
Added packetAliasMode to replace compiler #defines's (ee)
Allocates sockets for partially specified
ports if ALIAS_USE_SOCKETS defined. (cjm)
Version 2.0: March, 1997
SetAliasAddress() will now clean up alias links
if the aliasing address is changed. (cjm)
PacketAliasPermanentLink() function added to support permanent
links. (J. Fortes suggested the need for this.)
Examples:
(192.168.0.1, port 23) <-> alias port 6002, unknown dest addr/port
(192.168.0.2, port 21) <-> alias port 3604, known dest addr
unknown dest port
These permanent links allow for incoming connections to
machines on the local network. They can be given with a
user-chosen amount of specificity, with increasing specificity
meaning more security. (cjm)
Quite a bit of rework to the basic engine. The portTable[]
array, which kept track of which ports were in use was replaced
by a table/linked list structure. (cjm)
SetExpire() function added. (cjm)
DeleteLink() no longer frees memory association with a pointer
to a fragment (this bug was first recognized by E. Eklund in
v1.9).
Version 2.1: May, 1997 (cjm)
Packet aliasing engine reworked so that it can handle
multiple external addresses rather than just a single
host address.
PacketAliasRedirectPort() and PacketAliasRedirectAddr()
added to the API. The first function is a more generalized
version of PacketAliasPermanentLink(). The second function
implements static network address translation.
Version 3.2: July, 2000 (salander and satoh)
Added FindNewPortGroup to get contiguous range of port values.
Added QueryUdpTcpIn and QueryUdpTcpOut to look for an aliasing
link but not actually add one.
Added FindRtspOut, which is closely derived from FindUdpTcpOut,
except that the alias port (from FindNewPortGroup) is provided
as input.
See HISTORY file for additional revisions.
*/
#ifdef _KERNEL
#include <machine/stdarg.h>
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/rwlock.h>
#include <sys/syslog.h>
#else
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <unistd.h>
#endif
#include <sys/socket.h>
#include <netinet/tcp.h>
#ifdef _KERNEL
#include <netinet/libalias/alias.h>
#include <netinet/libalias/alias_local.h>
#include <netinet/libalias/alias_mod.h>
#include <net/if.h>
#else
#include "alias.h"
#include "alias_local.h"
#include "alias_mod.h"
#endif
static LIST_HEAD(, libalias) instancehead = LIST_HEAD_INITIALIZER(instancehead);
/*
Constants (note: constants are also defined
near relevant functions or structs)
*/
/* Parameters used for cleanup of expired links */
/* NOTE: ALIAS_CLEANUP_INTERVAL_SECS must be less then LINK_TABLE_OUT_SIZE */
#define ALIAS_CLEANUP_INTERVAL_SECS 64
#define ALIAS_CLEANUP_MAX_SPOKES (LINK_TABLE_OUT_SIZE/5)
/* Timeouts (in seconds) for different link types */
#define ICMP_EXPIRE_TIME 60
#define UDP_EXPIRE_TIME 60
#define PROTO_EXPIRE_TIME 60
#define FRAGMENT_ID_EXPIRE_TIME 10
#define FRAGMENT_PTR_EXPIRE_TIME 30
/* TCP link expire time for different cases */
/* When the link has been used and closed - minimal grace time to
allow ACKs and potential re-connect in FTP (XXX - is this allowed?) */
#ifndef TCP_EXPIRE_DEAD
#define TCP_EXPIRE_DEAD 10
#endif
/* When the link has been used and closed on one side - the other side
is allowed to still send data */
#ifndef TCP_EXPIRE_SINGLEDEAD
#define TCP_EXPIRE_SINGLEDEAD 90
#endif
/* When the link isn't yet up */
#ifndef TCP_EXPIRE_INITIAL
#define TCP_EXPIRE_INITIAL 300
#endif
/* When the link is up */
#ifndef TCP_EXPIRE_CONNECTED
#define TCP_EXPIRE_CONNECTED 86400
#endif
/* Dummy port number codes used for FindLinkIn/Out() and AddLink().
These constants can be anything except zero, which indicates an
unknown port number. */
#define NO_DEST_PORT 1
#define NO_SRC_PORT 1
/* Dummy address used for FindLinkIn/Out() and AddLink().
The value of this variable is never used. */
static struct in_addr const NO_ADDR;
/* Data Structures
The fundamental data structure used in this program is
"struct alias_link". Whenever a TCP connection is made,
a UDP datagram is sent out, or an ICMP echo request is made,
a link record is made (if it has not already been created).
The link record is identified by the source address/port
and the destination address/port. In the case of an ICMP
echo request, the source port is treated as being equivalent
with the 16-bit ID number of the ICMP packet.
The link record also can store some auxiliary data. For
TCP connections that have had sequence and acknowledgment
modifications, data space is available to track these changes.
A state field is used to keep track in changes to the TCP
connection state. ID numbers of fragments can also be
stored in the auxiliary space. Pointers to unresolved
fragments can also be stored.
The link records support two independent chainings. Lookup
tables for input and out tables hold the initial pointers
the link chains. On input, the lookup table indexes on alias
port and link type. On output, the lookup table indexes on
source address, destination address, source port, destination
port and link type.
*/
/* used to save changes to ACK/sequence numbers */
struct ack_data_record {
u_long ack_old;
u_long ack_new;
int delta;
int active;
};
/* Information about TCP connection */
struct tcp_state {
int in; /* State for outside -> inside */
int out; /* State for inside -> outside */
int index; /* Index to ACK data array */
/* Indicates whether ACK and sequence numbers been modified */
int ack_modified;
};
/* Number of distinct ACK number changes
* saved for a modified TCP stream */
#define N_LINK_TCP_DATA 3
struct tcp_dat {
struct tcp_state state;
struct ack_data_record ack[N_LINK_TCP_DATA];
/* Which firewall record is used for this hole? */
int fwhole;
};
/* LSNAT server pool (circular list) */
struct server {
struct in_addr addr;
u_short port;
struct server *next;
};
/* Main data structure */
struct alias_link {
struct libalias *la;
/* Address and port information */
struct in_addr src_addr;
struct in_addr dst_addr;
struct in_addr alias_addr;
struct in_addr proxy_addr;
u_short src_port;
u_short dst_port;
u_short alias_port;
u_short proxy_port;
struct server *server;
/* Type of link: TCP, UDP, ICMP, proto, frag */
int link_type;
/* values for link_type */
#define LINK_ICMP IPPROTO_ICMP
#define LINK_UDP IPPROTO_UDP
#define LINK_TCP IPPROTO_TCP
#define LINK_FRAGMENT_ID (IPPROTO_MAX + 1)
#define LINK_FRAGMENT_PTR (IPPROTO_MAX + 2)
#define LINK_ADDR (IPPROTO_MAX + 3)
#define LINK_PPTP (IPPROTO_MAX + 4)
int flags; /* indicates special characteristics */
int pflags; /* protocol-specific flags */
/* flag bits */
#define LINK_UNKNOWN_DEST_PORT 0x01
#define LINK_UNKNOWN_DEST_ADDR 0x02
#define LINK_PERMANENT 0x04
#define LINK_PARTIALLY_SPECIFIED 0x03 /* logical-or of first two bits */
#define LINK_UNFIREWALLED 0x08
int timestamp; /* Time link was last accessed */
int expire_time; /* Expire time for link */
#ifndef NO_USE_SOCKETS
int sockfd; /* socket descriptor */
#endif
/* Linked list of pointers for input and output lookup tables */
LIST_ENTRY (alias_link) list_out;
LIST_ENTRY (alias_link) list_in;
/* Auxiliary data */
union {
char *frag_ptr;
struct in_addr frag_addr;
struct tcp_dat *tcp;
} data;
};
/* Clean up procedure. */
static void finishoff(void);
/* Kernel module definition. */
#ifdef _KERNEL
MALLOC_DEFINE(M_ALIAS, "libalias", "packet aliasing");
MODULE_VERSION(libalias, 1);
static int
alias_mod_handler(module_t mod, int type, void *data)
{
switch (type) {
case MOD_QUIESCE:
case MOD_UNLOAD:
finishoff();
case MOD_LOAD:
return (0);
default:
return (EINVAL);
}
}
static moduledata_t alias_mod = {
"alias", alias_mod_handler, NULL
};
DECLARE_MODULE(alias, alias_mod, SI_SUB_DRIVERS, SI_ORDER_SECOND);
#endif
/* Internal utility routines (used only in alias_db.c)
Lookup table starting points:
StartPointIn() -- link table initial search point for
incoming packets
StartPointOut() -- link table initial search point for
outgoing packets
Miscellaneous:
SeqDiff() -- difference between two TCP sequences
ShowAliasStats() -- send alias statistics to a monitor file
*/
/* Local prototypes */
static u_int StartPointIn(struct in_addr, u_short, int);
static u_int
StartPointOut(struct in_addr, struct in_addr,
u_short, u_short, int);
static int SeqDiff(u_long, u_long);
#ifndef NO_FW_PUNCH
/* Firewall control */
static void InitPunchFW(struct libalias *);
static void UninitPunchFW(struct libalias *);
static void ClearFWHole(struct alias_link *);
#endif
/* Log file control */
static void ShowAliasStats(struct libalias *);
static int InitPacketAliasLog(struct libalias *);
static void UninitPacketAliasLog(struct libalias *);
void SctpShowAliasStats(struct libalias *la);
static u_int
StartPointIn(struct in_addr alias_addr,
u_short alias_port,
int link_type)
{
u_int n;
n = alias_addr.s_addr;
if (link_type != LINK_PPTP)
n += alias_port;
n += link_type;
return (n % LINK_TABLE_IN_SIZE);
}
static u_int
StartPointOut(struct in_addr src_addr, struct in_addr dst_addr,
u_short src_port, u_short dst_port, int link_type)
{
u_int n;
n = src_addr.s_addr;
n += dst_addr.s_addr;
if (link_type != LINK_PPTP) {
n += src_port;
n += dst_port;
}
n += link_type;
return (n % LINK_TABLE_OUT_SIZE);
}
static int
SeqDiff(u_long x, u_long y)
{
/* Return the difference between two TCP sequence numbers
* This function is encapsulated in case there are any unusual
* arithmetic conditions that need to be considered.
*/
return (ntohl(y) - ntohl(x));
}
#ifdef _KERNEL
static void
AliasLog(char *str, const char *format, ...)
{
va_list ap;
va_start(ap, format);
vsnprintf(str, LIBALIAS_BUF_SIZE, format, ap);
va_end(ap);
}
#else
static void
AliasLog(FILE *stream, const char *format, ...)
{
va_list ap;
va_start(ap, format);
vfprintf(stream, format, ap);
va_end(ap);
fflush(stream);
}
#endif
static void
ShowAliasStats(struct libalias *la)
{
LIBALIAS_LOCK_ASSERT(la);
/* Used for debugging */
if (la->logDesc) {
int tot = la->icmpLinkCount + la->udpLinkCount +
(la->sctpLinkCount>>1) + /* sctp counts half associations */
la->tcpLinkCount + la->pptpLinkCount +
la->protoLinkCount + la->fragmentIdLinkCount +
la->fragmentPtrLinkCount;
AliasLog(la->logDesc,
"icmp=%u, udp=%u, tcp=%u, sctp=%u, pptp=%u, proto=%u, frag_id=%u frag_ptr=%u / tot=%u",
la->icmpLinkCount,
la->udpLinkCount,
la->tcpLinkCount,
la->sctpLinkCount>>1, /* sctp counts half associations */
la->pptpLinkCount,
la->protoLinkCount,
la->fragmentIdLinkCount,
la->fragmentPtrLinkCount,
tot);
#ifndef _KERNEL
AliasLog(la->logDesc, " (sock=%u)\n", la->sockCount);
#endif
}
}
void SctpShowAliasStats(struct libalias *la)
{
ShowAliasStats(la);
}
/* Internal routines for finding, deleting and adding links
Port Allocation:
GetNewPort() -- find and reserve new alias port number
GetSocket() -- try to allocate a socket for a given port
Link creation and deletion:
CleanupAliasData() - remove all link chains from lookup table
IncrementalCleanup() - look for stale links in a single chain
DeleteLink() - remove link
AddLink() - add link
ReLink() - change link
Link search:
FindLinkOut() - find link for outgoing packets
FindLinkIn() - find link for incoming packets
Port search:
FindNewPortGroup() - find an available group of ports
*/
/* Local prototypes */
static int GetNewPort(struct libalias *, struct alias_link *, int);
#ifndef NO_USE_SOCKETS
static u_short GetSocket(struct libalias *, u_short, int *, int);
#endif
static void CleanupAliasData(struct libalias *);
static void IncrementalCleanup(struct libalias *);
static void DeleteLink(struct alias_link *);
static struct alias_link *
ReLink(struct alias_link *,
struct in_addr, struct in_addr, struct in_addr,
u_short, u_short, int, int);
static struct alias_link *
FindLinkOut(struct libalias *, struct in_addr, struct in_addr, u_short, u_short, int, int);
static struct alias_link *
FindLinkIn(struct libalias *, struct in_addr, struct in_addr, u_short, u_short, int, int);
#define ALIAS_PORT_BASE 0x08000
#define ALIAS_PORT_MASK 0x07fff
#define ALIAS_PORT_MASK_EVEN 0x07ffe
#define GET_NEW_PORT_MAX_ATTEMPTS 20
#define FIND_EVEN_ALIAS_BASE 1
/* GetNewPort() allocates port numbers. Note that if a port number
is already in use, that does not mean that it cannot be used by
another link concurrently. This is because GetNewPort() looks for
unused triplets: (dest addr, dest port, alias port). */
static int
GetNewPort(struct libalias *la, struct alias_link *lnk, int alias_port_param)
{
int i;
int max_trials;
u_short port_sys;
u_short port_net;
LIBALIAS_LOCK_ASSERT(la);
/*
* Description of alias_port_param for GetNewPort(). When
* this parameter is zero or positive, it precisely specifies
* the port number. GetNewPort() will return this number
* without check that it is in use.
* When this parameter is GET_ALIAS_PORT, it indicates to get
* a randomly selected port number.
*/
if (alias_port_param == GET_ALIAS_PORT) {
/*
* The aliasing port is automatically selected by one of
* two methods below:
*/
max_trials = GET_NEW_PORT_MAX_ATTEMPTS;
if (la->packetAliasMode & PKT_ALIAS_SAME_PORTS) {
/*
* When the PKT_ALIAS_SAME_PORTS option is chosen,
* the first try will be the actual source port. If
* this is already in use, the remainder of the
* trials will be random.
*/
port_net = lnk->src_port;
port_sys = ntohs(port_net);
} else if (la->aliasPortLower) {
/* First trial is a random port in the aliasing range. */
port_sys = la->aliasPortLower +
(arc4random() % la->aliasPortLength);
port_net = htons(port_sys);
} else {
/* First trial and all subsequent are random. */
port_sys = arc4random() & ALIAS_PORT_MASK;
port_sys += ALIAS_PORT_BASE;
port_net = htons(port_sys);
}
} else if (alias_port_param >= 0 && alias_port_param < 0x10000) {
lnk->alias_port = (u_short) alias_port_param;
return (0);
} else {
#ifdef LIBALIAS_DEBUG
fprintf(stderr, "PacketAlias/GetNewPort(): ");
fprintf(stderr, "input parameter error\n");
#endif
return (-1);
}
/* Port number search */
for (i = 0; i < max_trials; i++) {
int go_ahead;
struct alias_link *search_result;
search_result = FindLinkIn(la, lnk->dst_addr, lnk->alias_addr,
lnk->dst_port, port_net,
lnk->link_type, 0);
if (search_result == NULL)
go_ahead = 1;
else if (!(lnk->flags & LINK_PARTIALLY_SPECIFIED)
&& (search_result->flags & LINK_PARTIALLY_SPECIFIED))
go_ahead = 1;
else
go_ahead = 0;
if (go_ahead) {
#ifndef NO_USE_SOCKETS
if ((la->packetAliasMode & PKT_ALIAS_USE_SOCKETS)
&& (lnk->flags & LINK_PARTIALLY_SPECIFIED)
&& ((lnk->link_type == LINK_TCP) ||
(lnk->link_type == LINK_UDP))) {
if (GetSocket(la, port_net, &lnk->sockfd, lnk->link_type)) {
lnk->alias_port = port_net;
return (0);
}
} else {
#endif
lnk->alias_port = port_net;
return (0);
#ifndef NO_USE_SOCKETS
}
#endif
}
if (la->aliasPortLower) {
port_sys = la->aliasPortLower +
(arc4random() % la->aliasPortLength);
port_net = htons(port_sys);
} else {
port_sys = arc4random() & ALIAS_PORT_MASK;
port_sys += ALIAS_PORT_BASE;
port_net = htons(port_sys);
}
}
#ifdef LIBALIAS_DEBUG
fprintf(stderr, "PacketAlias/GetNewPort(): ");
fprintf(stderr, "could not find free port\n");
#endif
return (-1);
}
#ifndef NO_USE_SOCKETS
static u_short
GetSocket(struct libalias *la, u_short port_net, int *sockfd, int link_type)
{
int err;
int sock;
struct sockaddr_in sock_addr;
LIBALIAS_LOCK_ASSERT(la);
if (link_type == LINK_TCP)
sock = socket(AF_INET, SOCK_STREAM, 0);
else if (link_type == LINK_UDP)
sock = socket(AF_INET, SOCK_DGRAM, 0);
else {
#ifdef LIBALIAS_DEBUG
fprintf(stderr, "PacketAlias/GetSocket(): ");
fprintf(stderr, "incorrect link type\n");
#endif
return (0);
}
if (sock < 0) {
#ifdef LIBALIAS_DEBUG
fprintf(stderr, "PacketAlias/GetSocket(): ");
fprintf(stderr, "socket() error %d\n", *sockfd);
#endif
return (0);
}
sock_addr.sin_family = AF_INET;
sock_addr.sin_addr.s_addr = htonl(INADDR_ANY);
sock_addr.sin_port = port_net;
err = bind(sock,
(struct sockaddr *)&sock_addr,
sizeof(sock_addr));
if (err == 0) {
la->sockCount++;
*sockfd = sock;
return (1);
} else {
close(sock);
return (0);
}
}
#endif
/* FindNewPortGroup() returns a base port number for an available
range of contiguous port numbers. Note that if a port number
is already in use, that does not mean that it cannot be used by
another link concurrently. This is because FindNewPortGroup()
looks for unused triplets: (dest addr, dest port, alias port). */
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)
{
int i, j;
int max_trials;
u_short port_sys;
int link_type;
LIBALIAS_LOCK_ASSERT(la);
/*
* Get link_type from protocol
*/
switch (proto) {
case IPPROTO_UDP:
link_type = LINK_UDP;
break;
case IPPROTO_TCP:
link_type = LINK_TCP;
break;
default:
return (0);
break;
}
/*
* The aliasing port is automatically selected by one of two
* methods below:
*/
max_trials = GET_NEW_PORT_MAX_ATTEMPTS;
if (la->packetAliasMode & PKT_ALIAS_SAME_PORTS) {
/*
* When the ALIAS_SAME_PORTS option is chosen, the first
* try will be the actual source port. If this is already
* in use, the remainder of the trials will be random.
*/
port_sys = ntohs(src_port);
} else {
/* First trial and all subsequent are random. */
if (align == FIND_EVEN_ALIAS_BASE)
port_sys = arc4random() & ALIAS_PORT_MASK_EVEN;
else
port_sys = arc4random() & ALIAS_PORT_MASK;
port_sys += ALIAS_PORT_BASE;
}
/* Port number search */
for (i = 0; i < max_trials; i++) {
struct alias_link *search_result;
for (j = 0; j < port_count; j++)
if ((search_result = FindLinkIn(la, dst_addr,
alias_addr, dst_port, htons(port_sys + j),
link_type, 0)) != NULL)
break;
/* Found a good range, return base */
if (j == port_count)
return (htons(port_sys));
/* Find a new base to try */
if (align == FIND_EVEN_ALIAS_BASE)
port_sys = arc4random() & ALIAS_PORT_MASK_EVEN;
else
port_sys = arc4random() & ALIAS_PORT_MASK;
port_sys += ALIAS_PORT_BASE;
}
#ifdef LIBALIAS_DEBUG
fprintf(stderr, "PacketAlias/FindNewPortGroup(): ");
fprintf(stderr, "could not find free port(s)\n");
#endif
return (0);
}
static void
CleanupAliasData(struct libalias *la)
{
struct alias_link *lnk;
int i;
LIBALIAS_LOCK_ASSERT(la);
for (i = 0; i < LINK_TABLE_OUT_SIZE; i++) {
lnk = LIST_FIRST(&la->linkTableOut[i]);
while (lnk != NULL) {
struct alias_link *link_next = LIST_NEXT(lnk, list_out);
DeleteLink(lnk);
lnk = link_next;
}
}
la->cleanupIndex = 0;
}
static void
IncrementalCleanup(struct libalias *la)
{
struct alias_link *lnk, *lnk_tmp;
LIBALIAS_LOCK_ASSERT(la);
LIST_FOREACH_SAFE(lnk, &la->linkTableOut[la->cleanupIndex++],
list_out, lnk_tmp) {
if (la->timeStamp - lnk->timestamp > lnk->expire_time)
DeleteLink(lnk);
}
if (la->cleanupIndex == LINK_TABLE_OUT_SIZE)
la->cleanupIndex = 0;
}
static void
DeleteLink(struct alias_link *lnk)
{
struct libalias *la = lnk->la;
LIBALIAS_LOCK_ASSERT(la);
/* Don't do anything if the link is marked permanent */
if (la->deleteAllLinks == 0 && lnk->flags & LINK_PERMANENT)
return;
#ifndef NO_FW_PUNCH
/* Delete associated firewall hole, if any */
ClearFWHole(lnk);
#endif
/* Free memory allocated for LSNAT server pool */
if (lnk->server != NULL) {
struct server *head, *curr, *next;
head = curr = lnk->server;
do {
next = curr->next;
free(curr);
} while ((curr = next) != head);
}
/* Adjust output table pointers */
LIST_REMOVE(lnk, list_out);
/* Adjust input table pointers */
LIST_REMOVE(lnk, list_in);
#ifndef NO_USE_SOCKETS
/* Close socket, if one has been allocated */
if (lnk->sockfd != -1) {
la->sockCount--;
close(lnk->sockfd);
}
#endif
/* Link-type dependent cleanup */
switch (lnk->link_type) {
case LINK_ICMP:
la->icmpLinkCount--;
break;
case LINK_UDP:
la->udpLinkCount--;
break;
case LINK_TCP:
la->tcpLinkCount--;
free(lnk->data.tcp);
break;
case LINK_PPTP:
la->pptpLinkCount--;
break;
case LINK_FRAGMENT_ID:
la->fragmentIdLinkCount--;
break;
case LINK_FRAGMENT_PTR:
la->fragmentPtrLinkCount--;
if (lnk->data.frag_ptr != NULL)
free(lnk->data.frag_ptr);
break;
case LINK_ADDR:
break;
default:
la->protoLinkCount--;
break;
}
/* Free memory */
free(lnk);
/* Write statistics, if logging enabled */
if (la->packetAliasMode & PKT_ALIAS_LOG) {
ShowAliasStats(la);
}
}
struct alias_link *
AddLink(struct libalias *la, struct in_addr src_addr, struct in_addr dst_addr,
struct in_addr alias_addr, u_short src_port, u_short dst_port,
int alias_port_param, int link_type)
{
u_int start_point;
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
lnk = malloc(sizeof(struct alias_link));
if (lnk != NULL) {
/* Basic initialization */
lnk->la = la;
lnk->src_addr = src_addr;
lnk->dst_addr = dst_addr;
lnk->alias_addr = alias_addr;
lnk->proxy_addr.s_addr = INADDR_ANY;
lnk->src_port = src_port;
lnk->dst_port = dst_port;
lnk->proxy_port = 0;
lnk->server = NULL;
lnk->link_type = link_type;
#ifndef NO_USE_SOCKETS
lnk->sockfd = -1;
#endif
lnk->flags = 0;
lnk->pflags = 0;
lnk->timestamp = la->timeStamp;
/* Expiration time */
switch (link_type) {
case LINK_ICMP:
lnk->expire_time = ICMP_EXPIRE_TIME;
break;
case LINK_UDP:
lnk->expire_time = UDP_EXPIRE_TIME;
break;
case LINK_TCP:
lnk->expire_time = TCP_EXPIRE_INITIAL;
break;
case LINK_PPTP:
lnk->flags |= LINK_PERMANENT; /* no timeout. */
break;
case LINK_FRAGMENT_ID:
lnk->expire_time = FRAGMENT_ID_EXPIRE_TIME;
break;
case LINK_FRAGMENT_PTR:
lnk->expire_time = FRAGMENT_PTR_EXPIRE_TIME;
break;
case LINK_ADDR:
break;
default:
lnk->expire_time = PROTO_EXPIRE_TIME;
break;
}
/* Determine alias flags */
if (dst_addr.s_addr == INADDR_ANY)
lnk->flags |= LINK_UNKNOWN_DEST_ADDR;
if (dst_port == 0)
lnk->flags |= LINK_UNKNOWN_DEST_PORT;
/* Determine alias port */
if (GetNewPort(la, lnk, alias_port_param) != 0) {
free(lnk);
return (NULL);
}
/* Link-type dependent initialization */
switch (link_type) {
struct tcp_dat *aux_tcp;
case LINK_ICMP:
la->icmpLinkCount++;
break;
case LINK_UDP:
la->udpLinkCount++;
break;
case LINK_TCP:
aux_tcp = malloc(sizeof(struct tcp_dat));
if (aux_tcp != NULL) {
int i;
la->tcpLinkCount++;
aux_tcp->state.in = ALIAS_TCP_STATE_NOT_CONNECTED;
aux_tcp->state.out = ALIAS_TCP_STATE_NOT_CONNECTED;
aux_tcp->state.index = 0;
aux_tcp->state.ack_modified = 0;
for (i = 0; i < N_LINK_TCP_DATA; i++)
aux_tcp->ack[i].active = 0;
aux_tcp->fwhole = -1;
lnk->data.tcp = aux_tcp;
} else {
#ifdef LIBALIAS_DEBUG
fprintf(stderr, "PacketAlias/AddLink: ");
fprintf(stderr, " cannot allocate auxiliary TCP data\n");
#endif
free(lnk);
return (NULL);
}
break;
case LINK_PPTP:
la->pptpLinkCount++;
break;
case LINK_FRAGMENT_ID:
la->fragmentIdLinkCount++;
break;
case LINK_FRAGMENT_PTR:
la->fragmentPtrLinkCount++;
break;
case LINK_ADDR:
break;
default:
la->protoLinkCount++;
break;
}
/* Set up pointers for output lookup table */
start_point = StartPointOut(src_addr, dst_addr,
src_port, dst_port, link_type);
LIST_INSERT_HEAD(&la->linkTableOut[start_point], lnk, list_out);
/* Set up pointers for input lookup table */
start_point = StartPointIn(alias_addr, lnk->alias_port, link_type);
LIST_INSERT_HEAD(&la->linkTableIn[start_point], lnk, list_in);
} else {
#ifdef LIBALIAS_DEBUG
fprintf(stderr, "PacketAlias/AddLink(): ");
fprintf(stderr, "malloc() call failed.\n");
#endif
}
if (la->packetAliasMode & PKT_ALIAS_LOG) {
ShowAliasStats(la);
}
return (lnk);
}
/*
* If alias_port_param is less than zero, alias port will be automatically
* chosen. If greater than zero, equal to alias port
*/
static struct alias_link *
ReLink(struct alias_link *old_lnk,
struct in_addr src_addr,
struct in_addr dst_addr,
struct in_addr alias_addr,
u_short src_port,
u_short dst_port,
int alias_port_param,
int link_type)
{
struct alias_link *new_lnk;
struct libalias *la = old_lnk->la;
LIBALIAS_LOCK_ASSERT(la);
new_lnk = AddLink(la, src_addr, dst_addr, alias_addr,
src_port, dst_port, alias_port_param,
link_type);
#ifndef NO_FW_PUNCH
if (new_lnk != NULL &&
old_lnk->link_type == LINK_TCP &&
old_lnk->data.tcp->fwhole > 0) {
PunchFWHole(new_lnk);
}
#endif
DeleteLink(old_lnk);
return (new_lnk);
}
static struct alias_link *
_FindLinkOut(struct libalias *la, struct in_addr src_addr,
struct in_addr dst_addr,
u_short src_port,
u_short dst_port,
int link_type,
int replace_partial_links)
{
u_int i;
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
i = StartPointOut(src_addr, dst_addr, src_port, dst_port, link_type);
LIST_FOREACH(lnk, &la->linkTableOut[i], list_out) {
if (lnk->dst_addr.s_addr == dst_addr.s_addr &&
lnk->src_addr.s_addr == src_addr.s_addr &&
lnk->src_port == src_port &&
lnk->dst_port == dst_port &&
lnk->link_type == link_type &&
lnk->server == NULL) {
lnk->timestamp = la->timeStamp;
break;
}
}
/* Search for partially specified links. */
if (lnk == NULL && replace_partial_links) {
if (dst_port != 0 && dst_addr.s_addr != INADDR_ANY) {
lnk = _FindLinkOut(la, src_addr, dst_addr, src_port, 0,
link_type, 0);
if (lnk == NULL)
lnk = _FindLinkOut(la, src_addr, NO_ADDR, src_port,
dst_port, link_type, 0);
}
if (lnk == NULL &&
(dst_port != 0 || dst_addr.s_addr != INADDR_ANY)) {
lnk = _FindLinkOut(la, src_addr, NO_ADDR, src_port, 0,
link_type, 0);
}
if (lnk != NULL) {
lnk = ReLink(lnk,
src_addr, dst_addr, lnk->alias_addr,
src_port, dst_port, lnk->alias_port,
link_type);
}
}
return (lnk);
}
static struct alias_link *
FindLinkOut(struct libalias *la, struct in_addr src_addr,
struct in_addr dst_addr,
u_short src_port,
u_short dst_port,
int link_type,
int replace_partial_links)
{
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
lnk = _FindLinkOut(la, src_addr, dst_addr, src_port, dst_port,
link_type, replace_partial_links);
if (lnk == NULL) {
/*
* The following allows permanent links to be specified as
* using the default source address (i.e. device interface
* address) without knowing in advance what that address
* is.
*/
if (la->aliasAddress.s_addr != INADDR_ANY &&
src_addr.s_addr == la->aliasAddress.s_addr) {
lnk = _FindLinkOut(la, NO_ADDR, dst_addr, src_port, dst_port,
link_type, replace_partial_links);
}
}
return (lnk);
}
static struct alias_link *
_FindLinkIn(struct libalias *la, struct in_addr dst_addr,
struct in_addr alias_addr,
u_short dst_port,
u_short alias_port,
int link_type,
int replace_partial_links)
{
int flags_in;
u_int start_point;
struct alias_link *lnk;
struct alias_link *lnk_fully_specified;
struct alias_link *lnk_unknown_all;
struct alias_link *lnk_unknown_dst_addr;
struct alias_link *lnk_unknown_dst_port;
LIBALIAS_LOCK_ASSERT(la);
/* Initialize pointers */
lnk_fully_specified = NULL;
lnk_unknown_all = NULL;
lnk_unknown_dst_addr = NULL;
lnk_unknown_dst_port = NULL;
/* If either the dest addr or port is unknown, the search
* loop will have to know about this. */
flags_in = 0;
if (dst_addr.s_addr == INADDR_ANY)
flags_in |= LINK_UNKNOWN_DEST_ADDR;
if (dst_port == 0)
flags_in |= LINK_UNKNOWN_DEST_PORT;
/* Search loop */
start_point = StartPointIn(alias_addr, alias_port, link_type);
LIST_FOREACH(lnk, &la->linkTableIn[start_point], list_in) {
int flags;
flags = flags_in | lnk->flags;
if (!(flags & LINK_PARTIALLY_SPECIFIED)) {
if (lnk->alias_addr.s_addr == alias_addr.s_addr
&& lnk->alias_port == alias_port
&& lnk->dst_addr.s_addr == dst_addr.s_addr
&& lnk->dst_port == dst_port
&& lnk->link_type == link_type) {
lnk_fully_specified = lnk;
break;
}
} else if ((flags & LINK_UNKNOWN_DEST_ADDR)
&& (flags & LINK_UNKNOWN_DEST_PORT)) {
if (lnk->alias_addr.s_addr == alias_addr.s_addr
&& lnk->alias_port == alias_port
&& lnk->link_type == link_type) {
if (lnk_unknown_all == NULL)
lnk_unknown_all = lnk;
}
} else if (flags & LINK_UNKNOWN_DEST_ADDR) {
if (lnk->alias_addr.s_addr == alias_addr.s_addr
&& lnk->alias_port == alias_port
&& lnk->link_type == link_type
&& lnk->dst_port == dst_port) {
if (lnk_unknown_dst_addr == NULL)
lnk_unknown_dst_addr = lnk;
}
} else if (flags & LINK_UNKNOWN_DEST_PORT) {
if (lnk->alias_addr.s_addr == alias_addr.s_addr
&& lnk->alias_port == alias_port
&& lnk->link_type == link_type
&& lnk->dst_addr.s_addr == dst_addr.s_addr) {
if (lnk_unknown_dst_port == NULL)
lnk_unknown_dst_port = lnk;
}
}
}
if (lnk_fully_specified != NULL) {
lnk_fully_specified->timestamp = la->timeStamp;
lnk = lnk_fully_specified;
} else if (lnk_unknown_dst_port != NULL)
lnk = lnk_unknown_dst_port;
else if (lnk_unknown_dst_addr != NULL)
lnk = lnk_unknown_dst_addr;
else if (lnk_unknown_all != NULL)
lnk = lnk_unknown_all;
else
return (NULL);
if (replace_partial_links &&
(lnk->flags & LINK_PARTIALLY_SPECIFIED || lnk->server != NULL)) {
struct in_addr src_addr;
u_short src_port;
if (lnk->server != NULL) { /* LSNAT link */
src_addr = lnk->server->addr;
src_port = lnk->server->port;
lnk->server = lnk->server->next;
} else {
src_addr = lnk->src_addr;
src_port = lnk->src_port;
}
if (link_type == LINK_SCTP) {
lnk->src_addr = src_addr;
lnk->src_port = src_port;
return (lnk);
}
lnk = ReLink(lnk,
src_addr, dst_addr, alias_addr,
src_port, dst_port, alias_port,
link_type);
}
return (lnk);
}
static struct alias_link *
FindLinkIn(struct libalias *la, struct in_addr dst_addr,
struct in_addr alias_addr,
u_short dst_port,
u_short alias_port,
int link_type,
int replace_partial_links)
{
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
lnk = _FindLinkIn(la, dst_addr, alias_addr, dst_port, alias_port,
link_type, replace_partial_links);
if (lnk == NULL) {
/*
* The following allows permanent links to be specified as
* using the default aliasing address (i.e. device
* interface address) without knowing in advance what that
* address is.
*/
if (la->aliasAddress.s_addr != INADDR_ANY &&
alias_addr.s_addr == la->aliasAddress.s_addr) {
lnk = _FindLinkIn(la, dst_addr, NO_ADDR, dst_port, alias_port,
link_type, replace_partial_links);
}
}
return (lnk);
}
/* External routines for finding/adding links
-- "external" means outside alias_db.c, but within alias*.c --
FindIcmpIn(), FindIcmpOut()
FindFragmentIn1(), FindFragmentIn2()
AddFragmentPtrLink(), FindFragmentPtr()
FindProtoIn(), FindProtoOut()
FindUdpTcpIn(), FindUdpTcpOut()
AddPptp(), FindPptpOutByCallId(), FindPptpInByCallId(),
FindPptpOutByPeerCallId(), FindPptpInByPeerCallId()
FindOriginalAddress(), FindAliasAddress()
(prototypes in alias_local.h)
*/
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 *lnk;
LIBALIAS_LOCK_ASSERT(la);
lnk = FindLinkIn(la, dst_addr, alias_addr,
NO_DEST_PORT, id_alias,
LINK_ICMP, 0);
if (lnk == NULL && create && !(la->packetAliasMode & PKT_ALIAS_DENY_INCOMING)) {
struct in_addr target_addr;
target_addr = FindOriginalAddress(la, alias_addr);
lnk = AddLink(la, target_addr, dst_addr, alias_addr,
id_alias, NO_DEST_PORT, id_alias,
LINK_ICMP);
}
return (lnk);
}
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 *lnk;
LIBALIAS_LOCK_ASSERT(la);
lnk = FindLinkOut(la, src_addr, dst_addr,
id, NO_DEST_PORT,
LINK_ICMP, 0);
if (lnk == NULL && create) {
struct in_addr alias_addr;
alias_addr = FindAliasAddress(la, src_addr);
lnk = AddLink(la, src_addr, dst_addr, alias_addr,
id, NO_DEST_PORT, GET_ALIAS_ID,
LINK_ICMP);
}
return (lnk);
}
struct alias_link *
FindFragmentIn1(struct libalias *la, struct in_addr dst_addr,
struct in_addr alias_addr,
u_short ip_id)
{
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
lnk = FindLinkIn(la, dst_addr, alias_addr,
NO_DEST_PORT, ip_id,
LINK_FRAGMENT_ID, 0);
if (lnk == NULL) {
lnk = AddLink(la, NO_ADDR, dst_addr, alias_addr,
NO_SRC_PORT, NO_DEST_PORT, ip_id,
LINK_FRAGMENT_ID);
}
return (lnk);
}
/* Doesn't add a link if one is not found. */
struct alias_link *
FindFragmentIn2(struct libalias *la, struct in_addr dst_addr,
struct in_addr alias_addr, u_short ip_id)
{
LIBALIAS_LOCK_ASSERT(la);
return FindLinkIn(la, dst_addr, alias_addr,
NO_DEST_PORT, ip_id,
LINK_FRAGMENT_ID, 0);
}
struct alias_link *
AddFragmentPtrLink(struct libalias *la, struct in_addr dst_addr,
u_short ip_id)
{
LIBALIAS_LOCK_ASSERT(la);
return AddLink(la, NO_ADDR, dst_addr, NO_ADDR,
NO_SRC_PORT, NO_DEST_PORT, ip_id,
LINK_FRAGMENT_PTR);
}
struct alias_link *
FindFragmentPtr(struct libalias *la, struct in_addr dst_addr,
u_short ip_id)
{
LIBALIAS_LOCK_ASSERT(la);
return FindLinkIn(la, dst_addr, NO_ADDR,
NO_DEST_PORT, ip_id,
LINK_FRAGMENT_PTR, 0);
}
struct alias_link *
FindProtoIn(struct libalias *la, struct in_addr dst_addr,
struct in_addr alias_addr,
u_char proto)
{
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
lnk = FindLinkIn(la, dst_addr, alias_addr,
NO_DEST_PORT, 0,
proto, 1);
if (lnk == NULL && !(la->packetAliasMode & PKT_ALIAS_DENY_INCOMING)) {
struct in_addr target_addr;
target_addr = FindOriginalAddress(la, alias_addr);
lnk = AddLink(la, target_addr, dst_addr, alias_addr,
NO_SRC_PORT, NO_DEST_PORT, 0,
proto);
}
return (lnk);
}
struct alias_link *
FindProtoOut(struct libalias *la, struct in_addr src_addr,
struct in_addr dst_addr,
u_char proto)
{
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
lnk = FindLinkOut(la, src_addr, dst_addr,
NO_SRC_PORT, NO_DEST_PORT,
proto, 1);
if (lnk == NULL) {
struct in_addr alias_addr;
alias_addr = FindAliasAddress(la, src_addr);
lnk = AddLink(la, src_addr, dst_addr, alias_addr,
NO_SRC_PORT, NO_DEST_PORT, 0,
proto);
}
return (lnk);
}
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)
{
int link_type;
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
switch (proto) {
case IPPROTO_UDP:
link_type = LINK_UDP;
break;
case IPPROTO_TCP:
link_type = LINK_TCP;
break;
default:
return (NULL);
break;
}
lnk = FindLinkIn(la, dst_addr, alias_addr,
dst_port, alias_port,
link_type, create);
if (lnk == NULL && create && !(la->packetAliasMode & PKT_ALIAS_DENY_INCOMING)) {
struct in_addr target_addr;
target_addr = FindOriginalAddress(la, alias_addr);
lnk = AddLink(la, target_addr, dst_addr, alias_addr,
alias_port, dst_port, alias_port,
link_type);
}
return (lnk);
}
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)
{
int link_type;
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
switch (proto) {
case IPPROTO_UDP:
link_type = LINK_UDP;
break;
case IPPROTO_TCP:
link_type = LINK_TCP;
break;
default:
return (NULL);
break;
}
lnk = FindLinkOut(la, src_addr, dst_addr, src_port, dst_port, link_type, create);
if (lnk == NULL && create) {
struct in_addr alias_addr;
alias_addr = FindAliasAddress(la, src_addr);
lnk = AddLink(la, src_addr, dst_addr, alias_addr,
src_port, dst_port, GET_ALIAS_PORT,
link_type);
}
return (lnk);
}
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 *lnk;
LIBALIAS_LOCK_ASSERT(la);
lnk = AddLink(la, src_addr, dst_addr, alias_addr,
src_call_id, 0, GET_ALIAS_PORT,
LINK_PPTP);
return (lnk);
}
struct alias_link *
FindPptpOutByCallId(struct libalias *la, struct in_addr src_addr,
struct in_addr dst_addr,
u_int16_t src_call_id)
{
u_int i;
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
i = StartPointOut(src_addr, dst_addr, 0, 0, LINK_PPTP);
LIST_FOREACH(lnk, &la->linkTableOut[i], list_out)
if (lnk->link_type == LINK_PPTP &&
lnk->src_addr.s_addr == src_addr.s_addr &&
lnk->dst_addr.s_addr == dst_addr.s_addr &&
lnk->src_port == src_call_id)
break;
return (lnk);
}
struct alias_link *
FindPptpOutByPeerCallId(struct libalias *la, struct in_addr src_addr,
struct in_addr dst_addr,
u_int16_t dst_call_id)
{
u_int i;
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
i = StartPointOut(src_addr, dst_addr, 0, 0, LINK_PPTP);
LIST_FOREACH(lnk, &la->linkTableOut[i], list_out)
if (lnk->link_type == LINK_PPTP &&
lnk->src_addr.s_addr == src_addr.s_addr &&
lnk->dst_addr.s_addr == dst_addr.s_addr &&
lnk->dst_port == dst_call_id)
break;
return (lnk);
}
struct alias_link *
FindPptpInByCallId(struct libalias *la, struct in_addr dst_addr,
struct in_addr alias_addr,
u_int16_t dst_call_id)
{
u_int i;
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
i = StartPointIn(alias_addr, 0, LINK_PPTP);
LIST_FOREACH(lnk, &la->linkTableIn[i], list_in)
if (lnk->link_type == LINK_PPTP &&
lnk->dst_addr.s_addr == dst_addr.s_addr &&
lnk->alias_addr.s_addr == alias_addr.s_addr &&
lnk->dst_port == dst_call_id)
break;
return (lnk);
}
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 *lnk;
LIBALIAS_LOCK_ASSERT(la);
lnk = FindLinkIn(la, dst_addr, alias_addr,
0 /* any */ , alias_call_id,
LINK_PPTP, 0);
return (lnk);
}
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)
{
int link_type;
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
switch (proto) {
case IPPROTO_UDP:
link_type = LINK_UDP;
break;
case IPPROTO_TCP:
link_type = LINK_TCP;
break;
default:
return (NULL);
break;
}
lnk = FindLinkOut(la, src_addr, dst_addr, src_port, 0, link_type, 1);
if (lnk == NULL) {
struct in_addr alias_addr;
alias_addr = FindAliasAddress(la, src_addr);
lnk = AddLink(la, src_addr, dst_addr, alias_addr,
src_port, 0, alias_port,
link_type);
}
return (lnk);
}
struct in_addr
FindOriginalAddress(struct libalias *la, struct in_addr alias_addr)
{
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
lnk = FindLinkIn(la, NO_ADDR, alias_addr,
0, 0, LINK_ADDR, 0);
if (lnk == NULL) {
la->newDefaultLink = 1;
if (la->targetAddress.s_addr == INADDR_ANY)
return (alias_addr);
else if (la->targetAddress.s_addr == INADDR_NONE)
return (la->aliasAddress.s_addr != INADDR_ANY) ?
la->aliasAddress : alias_addr;
else
return (la->targetAddress);
} else {
if (lnk->server != NULL) { /* LSNAT link */
struct in_addr src_addr;
src_addr = lnk->server->addr;
lnk->server = lnk->server->next;
return (src_addr);
} else if (lnk->src_addr.s_addr == INADDR_ANY)
return (la->aliasAddress.s_addr != INADDR_ANY) ?
la->aliasAddress : alias_addr;
else
return (lnk->src_addr);
}
}
struct in_addr
FindAliasAddress(struct libalias *la, struct in_addr original_addr)
{
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
lnk = FindLinkOut(la, original_addr, NO_ADDR,
0, 0, LINK_ADDR, 0);
if (lnk == NULL) {
return (la->aliasAddress.s_addr != INADDR_ANY) ?
la->aliasAddress : original_addr;
} else {
if (lnk->alias_addr.s_addr == INADDR_ANY)
return (la->aliasAddress.s_addr != INADDR_ANY) ?
la->aliasAddress : original_addr;
else
return (lnk->alias_addr);
}
}
/* External routines for getting or changing link data
(external to alias_db.c, but internal to alias*.c)
SetFragmentData(), GetFragmentData()
SetFragmentPtr(), GetFragmentPtr()
SetStateIn(), SetStateOut(), GetStateIn(), GetStateOut()
GetOriginalAddress(), GetDestAddress(), GetAliasAddress()
GetOriginalPort(), GetAliasPort()
SetAckModified(), GetAckModified()
GetDeltaAckIn(), GetDeltaSeqOut(), AddSeq()
SetProtocolFlags(), GetProtocolFlags()
SetDestCallId()
*/
void
SetFragmentAddr(struct alias_link *lnk, struct in_addr src_addr)
{
lnk->data.frag_addr = src_addr;
}
void
GetFragmentAddr(struct alias_link *lnk, struct in_addr *src_addr)
{
*src_addr = lnk->data.frag_addr;
}
void
SetFragmentPtr(struct alias_link *lnk, void *fptr)
{
lnk->data.frag_ptr = fptr;
}
void
GetFragmentPtr(struct alias_link *lnk, void **fptr)
{
*fptr = lnk->data.frag_ptr;
}
void
SetStateIn(struct alias_link *lnk, int state)
{
/* TCP input state */
switch (state) {
case ALIAS_TCP_STATE_DISCONNECTED:
if (lnk->data.tcp->state.out != ALIAS_TCP_STATE_CONNECTED)
lnk->expire_time = TCP_EXPIRE_DEAD;
else
lnk->expire_time = TCP_EXPIRE_SINGLEDEAD;
break;
case ALIAS_TCP_STATE_CONNECTED:
if (lnk->data.tcp->state.out == ALIAS_TCP_STATE_CONNECTED)
lnk->expire_time = TCP_EXPIRE_CONNECTED;
break;
default:
#ifdef _KERNEL
panic("libalias:SetStateIn() unknown state");
#else
abort();
#endif
}
lnk->data.tcp->state.in = state;
}
void
SetStateOut(struct alias_link *lnk, int state)
{
/* TCP output state */
switch (state) {
case ALIAS_TCP_STATE_DISCONNECTED:
if (lnk->data.tcp->state.in != ALIAS_TCP_STATE_CONNECTED)
lnk->expire_time = TCP_EXPIRE_DEAD;
else
lnk->expire_time = TCP_EXPIRE_SINGLEDEAD;
break;
case ALIAS_TCP_STATE_CONNECTED:
if (lnk->data.tcp->state.in == ALIAS_TCP_STATE_CONNECTED)
lnk->expire_time = TCP_EXPIRE_CONNECTED;
break;
default:
#ifdef _KERNEL
panic("libalias:SetStateOut() unknown state");
#else
abort();
#endif
}
lnk->data.tcp->state.out = state;
}
int
GetStateIn(struct alias_link *lnk)
{
/* TCP input state */
return (lnk->data.tcp->state.in);
}
int
GetStateOut(struct alias_link *lnk)
{
/* TCP output state */
return (lnk->data.tcp->state.out);
}
struct in_addr
GetOriginalAddress(struct alias_link *lnk)
{
if (lnk->src_addr.s_addr == INADDR_ANY)
return (lnk->la->aliasAddress);
else
return (lnk->src_addr);
}
struct in_addr
GetDestAddress(struct alias_link *lnk)
{
return (lnk->dst_addr);
}
struct in_addr
GetAliasAddress(struct alias_link *lnk)
{
if (lnk->alias_addr.s_addr == INADDR_ANY)
return (lnk->la->aliasAddress);
else
return (lnk->alias_addr);
}
struct in_addr
GetDefaultAliasAddress(struct libalias *la)
{
LIBALIAS_LOCK_ASSERT(la);
return (la->aliasAddress);
}
void
SetDefaultAliasAddress(struct libalias *la, struct in_addr alias_addr)
{
LIBALIAS_LOCK_ASSERT(la);
la->aliasAddress = alias_addr;
}
u_short
GetOriginalPort(struct alias_link *lnk)
{
return (lnk->src_port);
}
u_short
GetAliasPort(struct alias_link *lnk)
{
return (lnk->alias_port);
}
#ifndef NO_FW_PUNCH
static u_short
GetDestPort(struct alias_link *lnk)
{
return (lnk->dst_port);
}
#endif
/* Indicate that ACK numbers have been modified in a TCP connection */
void
SetAckModified(struct alias_link *lnk)
{
lnk->data.tcp->state.ack_modified = 1;
}
struct in_addr
GetProxyAddress(struct alias_link *lnk)
{
return (lnk->proxy_addr);
}
void
SetProxyAddress(struct alias_link *lnk, struct in_addr addr)
{
lnk->proxy_addr = addr;
}
u_short
GetProxyPort(struct alias_link *lnk)
{
return (lnk->proxy_port);
}
void
SetProxyPort(struct alias_link *lnk, u_short port)
{
lnk->proxy_port = port;
}
/* See if ACK numbers have been modified */
int
GetAckModified(struct alias_link *lnk)
{
return (lnk->data.tcp->state.ack_modified);
}
/*
* Find out how much the ACK number has been altered for an
* incoming TCP packet. To do this, a circular list of ACK
* numbers where the TCP packet size was altered is searched.
*/
// XXX ip free
int
GetDeltaAckIn(u_long ack, struct alias_link *lnk)
{
int i, j;
int delta, ack_diff_min;
delta = 0;
ack_diff_min = -1;
i = lnk->data.tcp->state.index;
for (j = 0; j < N_LINK_TCP_DATA; j++) {
struct ack_data_record x;
if (i == 0)
i = N_LINK_TCP_DATA;
i--;
x = lnk->data.tcp->ack[i];
if (x.active == 1) {
int ack_diff;
ack_diff = SeqDiff(x.ack_new, ack);
if (ack_diff >= 0) {
if (ack_diff_min >= 0) {
if (ack_diff < ack_diff_min) {
delta = x.delta;
ack_diff_min = ack_diff;
}
} else {
delta = x.delta;
ack_diff_min = ack_diff;
}
}
}
}
return (delta);
}
/*
* Find out how much the sequence number has been altered for an
* outgoing TCP packet. To do this, a circular list of ACK numbers
* where the TCP packet size was altered is searched.
*/
// XXX ip free
int
GetDeltaSeqOut(u_long seq, struct alias_link *lnk)
{
int i, j;
int delta, seq_diff_min;
delta = 0;
seq_diff_min = -1;
i = lnk->data.tcp->state.index;
for (j = 0; j < N_LINK_TCP_DATA; j++) {
struct ack_data_record x;
if (i == 0)
i = N_LINK_TCP_DATA;
i--;
x = lnk->data.tcp->ack[i];
if (x.active == 1) {
int seq_diff;
seq_diff = SeqDiff(x.ack_old, seq);
if (seq_diff >= 0) {
if (seq_diff_min >= 0) {
if (seq_diff < seq_diff_min) {
delta = x.delta;
seq_diff_min = seq_diff;
}
} else {
delta = x.delta;
seq_diff_min = seq_diff;
}
}
}
}
return (delta);
}
/*
* When a TCP packet has been altered in length, save this
* information in a circular list. If enough packets have been
* altered, then this list will begin to overwrite itself.
*/
// XXX ip free
void
AddSeq(struct alias_link *lnk, int delta, u_int ip_hl, u_short ip_len,
u_long th_seq, u_int th_off)
{
struct ack_data_record x;
int hlen, tlen, dlen;
int i;
hlen = (ip_hl + th_off) << 2;
tlen = ntohs(ip_len);
dlen = tlen - hlen;
x.ack_old = htonl(ntohl(th_seq) + dlen);
x.ack_new = htonl(ntohl(th_seq) + dlen + delta);
x.delta = delta;
x.active = 1;
i = lnk->data.tcp->state.index;
lnk->data.tcp->ack[i] = x;
i++;
if (i == N_LINK_TCP_DATA)
lnk->data.tcp->state.index = 0;
else
lnk->data.tcp->state.index = i;
}
void
SetExpire(struct alias_link *lnk, int expire)
{
if (expire == 0) {
lnk->flags &= ~LINK_PERMANENT;
DeleteLink(lnk);
} else if (expire == -1) {
lnk->flags |= LINK_PERMANENT;
} else if (expire > 0) {
lnk->expire_time = expire;
} else {
#ifdef LIBALIAS_DEBUG
fprintf(stderr, "PacketAlias/SetExpire(): ");
fprintf(stderr, "error in expire parameter\n");
#endif
}
}
void
ClearCheckNewLink(struct libalias *la)
{
LIBALIAS_LOCK_ASSERT(la);
la->newDefaultLink = 0;
}
void
SetProtocolFlags(struct alias_link *lnk, int pflags)
{
lnk->pflags = pflags;
}
int
GetProtocolFlags(struct alias_link *lnk)
{
return (lnk->pflags);
}
void
SetDestCallId(struct alias_link *lnk, u_int16_t cid)
{
struct libalias *la = lnk->la;
LIBALIAS_LOCK_ASSERT(la);
la->deleteAllLinks = 1;
ReLink(lnk, lnk->src_addr, lnk->dst_addr, lnk->alias_addr,
lnk->src_port, cid, lnk->alias_port, lnk->link_type);
la->deleteAllLinks = 0;
}
/* Miscellaneous Functions
HouseKeeping()
InitPacketAliasLog()
UninitPacketAliasLog()
*/
/*
Whenever an outgoing or incoming packet is handled, HouseKeeping()
is called to find and remove timed-out aliasing links. Logic exists
to sweep through the entire table and linked list structure
every 60 seconds.
(prototype in alias_local.h)
*/
void
HouseKeeping(struct libalias *la)
{
int i, n;
#ifndef _KERNEL
struct timeval tv;
#endif
LIBALIAS_LOCK_ASSERT(la);
/*
* Save system time (seconds) in global variable timeStamp for use
* by other functions. This is done so as not to unnecessarily
* waste timeline by making system calls.
*/
#ifdef _KERNEL
la->timeStamp = time_uptime;
#else
gettimeofday(&tv, NULL);
la->timeStamp = tv.tv_sec;
#endif
/* Compute number of spokes (output table link chains) to cover */
n = LINK_TABLE_OUT_SIZE * (la->timeStamp - la->lastCleanupTime);
n /= ALIAS_CLEANUP_INTERVAL_SECS;
/* Handle different cases */
if (n > 0) {
if (n > ALIAS_CLEANUP_MAX_SPOKES)
n = ALIAS_CLEANUP_MAX_SPOKES;
la->lastCleanupTime = la->timeStamp;
for (i = 0; i < n; i++)
IncrementalCleanup(la);
} else if (n < 0) {
#ifdef LIBALIAS_DEBUG
fprintf(stderr, "PacketAlias/HouseKeeping(): ");
fprintf(stderr, "something unexpected in time values\n");
#endif
la->lastCleanupTime = la->timeStamp;
}
}
/* Init the log file and enable logging */
static int
InitPacketAliasLog(struct libalias *la)
{
LIBALIAS_LOCK_ASSERT(la);
if (~la->packetAliasMode & PKT_ALIAS_LOG) {
#ifdef _KERNEL
if ((la->logDesc = malloc(LIBALIAS_BUF_SIZE)))
;
#else
if ((la->logDesc = fopen("/var/log/alias.log", "w")))
fprintf(la->logDesc, "PacketAlias/InitPacketAliasLog: Packet alias logging enabled.\n");
#endif
else
return (ENOMEM); /* log initialization failed */
la->packetAliasMode |= PKT_ALIAS_LOG;
}
return (1);
}
/* Close the log-file and disable logging. */
static void
UninitPacketAliasLog(struct libalias *la)
{
LIBALIAS_LOCK_ASSERT(la);
if (la->logDesc) {
#ifdef _KERNEL
free(la->logDesc);
#else
fclose(la->logDesc);
#endif
la->logDesc = NULL;
}
la->packetAliasMode &= ~PKT_ALIAS_LOG;
}
/* Outside world interfaces
-- "outside world" means other than alias*.c routines --
PacketAliasRedirectPort()
PacketAliasAddServer()
PacketAliasRedirectProto()
PacketAliasRedirectAddr()
PacketAliasRedirectDynamic()
PacketAliasRedirectDelete()
PacketAliasSetAddress()
PacketAliasInit()
PacketAliasUninit()
PacketAliasSetMode()
(prototypes in alias.h)
*/
/* Redirection from a specific public addr:port to a
private addr:port */
struct alias_link *
LibAliasRedirectPort(struct libalias *la, struct in_addr src_addr, u_short src_port,
struct in_addr dst_addr, u_short dst_port,
struct in_addr alias_addr, u_short alias_port,
u_char proto)
{
int link_type;
struct alias_link *lnk;
LIBALIAS_LOCK(la);
switch (proto) {
case IPPROTO_UDP:
link_type = LINK_UDP;
break;
case IPPROTO_TCP:
link_type = LINK_TCP;
break;
case IPPROTO_SCTP:
link_type = LINK_SCTP;
break;
default:
#ifdef LIBALIAS_DEBUG
fprintf(stderr, "PacketAliasRedirectPort(): ");
fprintf(stderr, "only SCTP, TCP and UDP protocols allowed\n");
#endif
lnk = NULL;
goto getout;
}
lnk = AddLink(la, src_addr, dst_addr, alias_addr,
src_port, dst_port, alias_port,
link_type);
if (lnk != NULL) {
lnk->flags |= LINK_PERMANENT;
}
#ifdef LIBALIAS_DEBUG
else {
fprintf(stderr, "PacketAliasRedirectPort(): "
"call to AddLink() failed\n");
}
#endif
getout:
LIBALIAS_UNLOCK(la);
return (lnk);
}
/* Add server to the pool of servers */
int
LibAliasAddServer(struct libalias *la, struct alias_link *lnk, struct in_addr addr, u_short port)
{
struct server *server;
int res;
LIBALIAS_LOCK(la);
(void)la;
server = malloc(sizeof(struct server));
if (server != NULL) {
struct server *head;
server->addr = addr;
server->port = port;
head = lnk->server;
if (head == NULL)
server->next = server;
else {
struct server *s;
for (s = head; s->next != head; s = s->next)
;
s->next = server;
server->next = head;
}
lnk->server = server;
res = 0;
} else
res = -1;
LIBALIAS_UNLOCK(la);
return (res);
}
/* Redirect packets of a given IP protocol from a specific
public address to a private address */
struct alias_link *
LibAliasRedirectProto(struct libalias *la, struct in_addr src_addr,
struct in_addr dst_addr,
struct in_addr alias_addr,
u_char proto)
{
struct alias_link *lnk;
LIBALIAS_LOCK(la);
lnk = AddLink(la, src_addr, dst_addr, alias_addr,
NO_SRC_PORT, NO_DEST_PORT, 0,
proto);
if (lnk != NULL) {
lnk->flags |= LINK_PERMANENT;
}
#ifdef LIBALIAS_DEBUG
else {
fprintf(stderr, "PacketAliasRedirectProto(): "
"call to AddLink() failed\n");
}
#endif
LIBALIAS_UNLOCK(la);
return (lnk);
}
/* Static address translation */
struct alias_link *
LibAliasRedirectAddr(struct libalias *la, struct in_addr src_addr,
struct in_addr alias_addr)
{
struct alias_link *lnk;
LIBALIAS_LOCK(la);
lnk = AddLink(la, src_addr, NO_ADDR, alias_addr,
0, 0, 0,
LINK_ADDR);
if (lnk != NULL) {
lnk->flags |= LINK_PERMANENT;
}
#ifdef LIBALIAS_DEBUG
else {
fprintf(stderr, "PacketAliasRedirectAddr(): "
"call to AddLink() failed\n");
}
#endif
LIBALIAS_UNLOCK(la);
return (lnk);
}
/* Mark the aliasing link dynamic */
int
LibAliasRedirectDynamic(struct libalias *la, struct alias_link *lnk)
{
int res;
LIBALIAS_LOCK(la);
(void)la;
if (lnk->flags & LINK_PARTIALLY_SPECIFIED)
res = -1;
else {
lnk->flags &= ~LINK_PERMANENT;
res = 0;
}
LIBALIAS_UNLOCK(la);
return (res);
}
/* This is a dangerous function to put in the API,
because an invalid pointer can crash the program. */
void
LibAliasRedirectDelete(struct libalias *la, struct alias_link *lnk)
{
LIBALIAS_LOCK(la);
la->deleteAllLinks = 1;
DeleteLink(lnk);
la->deleteAllLinks = 0;
LIBALIAS_UNLOCK(la);
}
void
LibAliasSetAddress(struct libalias *la, struct in_addr addr)
{
LIBALIAS_LOCK(la);
if (la->packetAliasMode & PKT_ALIAS_RESET_ON_ADDR_CHANGE
&& la->aliasAddress.s_addr != addr.s_addr)
CleanupAliasData(la);
la->aliasAddress = addr;
LIBALIAS_UNLOCK(la);
}
void
LibAliasSetAliasPortRange(struct libalias *la, u_short port_low,
u_short port_high)
{
LIBALIAS_LOCK(la);
la->aliasPortLower = port_low;
/* Add 1 to the aliasPortLength as modulo has range of 1 to n-1 */
la->aliasPortLength = port_high - port_low + 1;
LIBALIAS_UNLOCK(la);
}
void
LibAliasSetTarget(struct libalias *la, struct in_addr target_addr)
{
LIBALIAS_LOCK(la);
la->targetAddress = target_addr;
LIBALIAS_UNLOCK(la);
}
static void
finishoff(void)
{
while (!LIST_EMPTY(&instancehead))
LibAliasUninit(LIST_FIRST(&instancehead));
}
struct libalias *
LibAliasInit(struct libalias *la)
{
int i;
#ifndef _KERNEL
struct timeval tv;
#endif
if (la == NULL) {
#ifdef _KERNEL
#undef malloc /* XXX: ugly */
la = malloc(sizeof *la, M_ALIAS, M_WAITOK | M_ZERO);
#else
la = calloc(sizeof *la, 1);
if (la == NULL)
return (la);
#endif
#ifndef _KERNEL
/* kernel cleans up on module unload */
if (LIST_EMPTY(&instancehead))
atexit(finishoff);
#endif
LIST_INSERT_HEAD(&instancehead, la, instancelist);
#ifdef _KERNEL
la->timeStamp = time_uptime;
la->lastCleanupTime = time_uptime;
#else
gettimeofday(&tv, NULL);
la->timeStamp = tv.tv_sec;
la->lastCleanupTime = tv.tv_sec;
#endif
for (i = 0; i < LINK_TABLE_OUT_SIZE; i++)
LIST_INIT(&la->linkTableOut[i]);
for (i = 0; i < LINK_TABLE_IN_SIZE; i++)
LIST_INIT(&la->linkTableIn[i]);
#ifdef _KERNEL
AliasSctpInit(la);
#endif
LIBALIAS_LOCK_INIT(la);
LIBALIAS_LOCK(la);
} else {
LIBALIAS_LOCK(la);
la->deleteAllLinks = 1;
CleanupAliasData(la);
la->deleteAllLinks = 0;
#ifdef _KERNEL
AliasSctpTerm(la);
AliasSctpInit(la);
#endif
}
la->aliasAddress.s_addr = INADDR_ANY;
la->targetAddress.s_addr = INADDR_ANY;
la->icmpLinkCount = 0;
la->udpLinkCount = 0;
la->tcpLinkCount = 0;
la->sctpLinkCount = 0;
la->pptpLinkCount = 0;
la->protoLinkCount = 0;
la->fragmentIdLinkCount = 0;
la->fragmentPtrLinkCount = 0;
la->sockCount = 0;
la->cleanupIndex = 0;
la->packetAliasMode = PKT_ALIAS_SAME_PORTS
#ifndef NO_USE_SOCKETS
| PKT_ALIAS_USE_SOCKETS
#endif
| PKT_ALIAS_RESET_ON_ADDR_CHANGE;
#ifndef NO_FW_PUNCH
la->fireWallFD = -1;
#endif
#ifndef _KERNEL
LibAliasRefreshModules();
#endif
LIBALIAS_UNLOCK(la);
return (la);
}
void
LibAliasUninit(struct libalias *la)
{
LIBALIAS_LOCK(la);
#ifdef _KERNEL
AliasSctpTerm(la);
#endif
la->deleteAllLinks = 1;
CleanupAliasData(la);
la->deleteAllLinks = 0;
UninitPacketAliasLog(la);
#ifndef NO_FW_PUNCH
UninitPunchFW(la);
#endif
LIST_REMOVE(la, instancelist);
LIBALIAS_UNLOCK(la);
LIBALIAS_LOCK_DESTROY(la);
free(la);
}
/* Change mode for some operations */
unsigned int
LibAliasSetMode(
struct libalias *la,
unsigned int flags, /* Which state to bring flags to */
unsigned int mask /* Mask of which flags to affect (use 0 to
* do a probe for flag values) */
)
{
int res = -1;
LIBALIAS_LOCK(la);
if (flags & mask & PKT_ALIAS_LOG) {
/* Enable logging */
if (InitPacketAliasLog(la) == ENOMEM)
goto getout;
} else if (~flags & mask & PKT_ALIAS_LOG)
/* _Disable_ logging */
UninitPacketAliasLog(la);
#ifndef NO_FW_PUNCH
if (flags & mask & PKT_ALIAS_PUNCH_FW)
/* Start punching holes in the firewall? */
InitPunchFW(la);
else if (~flags & mask & PKT_ALIAS_PUNCH_FW)
/* Stop punching holes in the firewall? */
UninitPunchFW(la);
#endif
/* Other flags can be set/cleared without special action */
la->packetAliasMode = (flags & mask) | (la->packetAliasMode & ~mask);
res = la->packetAliasMode;
getout:
LIBALIAS_UNLOCK(la);
return (res);
}
int
LibAliasCheckNewLink(struct libalias *la)
{
int res;
LIBALIAS_LOCK(la);
res = la->newDefaultLink;
LIBALIAS_UNLOCK(la);
return (res);
}
#ifndef NO_FW_PUNCH
/*****************
Code to support firewall punching. This shouldn't really be in this
file, but making variables global is evil too.
****************/
/* Firewall include files */
#include <net/if.h>
#include <netinet/ip_fw.h>
#include <string.h>
#include <err.h>
/*
* helper function, updates the pointer to cmd with the length
* of the current command, and also cleans up the first word of
* the new command in case it has been clobbered before.
*/
static ipfw_insn *
next_cmd(ipfw_insn * cmd)
{
cmd += F_LEN(cmd);
bzero(cmd, sizeof(*cmd));
return (cmd);
}
/*
* A function to fill simple commands of size 1.
* Existing flags are preserved.
*/
static ipfw_insn *
fill_cmd(ipfw_insn * cmd, enum ipfw_opcodes opcode, int size,
int flags, u_int16_t arg)
{
cmd->opcode = opcode;
cmd->len = ((cmd->len | flags) & (F_NOT | F_OR)) | (size & F_LEN_MASK);
cmd->arg1 = arg;
return next_cmd(cmd);
}
static ipfw_insn *
fill_ip(ipfw_insn * cmd1, enum ipfw_opcodes opcode, u_int32_t addr)
{
ipfw_insn_ip *cmd = (ipfw_insn_ip *)cmd1;
cmd->addr.s_addr = addr;
return fill_cmd(cmd1, opcode, F_INSN_SIZE(ipfw_insn_u32), 0, 0);
}
static ipfw_insn *
fill_one_port(ipfw_insn * cmd1, enum ipfw_opcodes opcode, u_int16_t port)
{
ipfw_insn_u16 *cmd = (ipfw_insn_u16 *)cmd1;
cmd->ports[0] = cmd->ports[1] = port;
return fill_cmd(cmd1, opcode, F_INSN_SIZE(ipfw_insn_u16), 0, 0);
}
static int
fill_rule(void *buf, int bufsize, int rulenum,
enum ipfw_opcodes action, int proto,
struct in_addr sa, u_int16_t sp, struct in_addr da, u_int16_t dp)
{
struct ip_fw *rule = (struct ip_fw *)buf;
ipfw_insn *cmd = (ipfw_insn *)rule->cmd;
bzero(buf, bufsize);
rule->rulenum = rulenum;
cmd = fill_cmd(cmd, O_PROTO, F_INSN_SIZE(ipfw_insn), 0, proto);
cmd = fill_ip(cmd, O_IP_SRC, sa.s_addr);
cmd = fill_one_port(cmd, O_IP_SRCPORT, sp);
cmd = fill_ip(cmd, O_IP_DST, da.s_addr);
cmd = fill_one_port(cmd, O_IP_DSTPORT, dp);
rule->act_ofs = (u_int32_t *)cmd - (u_int32_t *)rule->cmd;
cmd = fill_cmd(cmd, action, F_INSN_SIZE(ipfw_insn), 0, 0);
rule->cmd_len = (u_int32_t *)cmd - (u_int32_t *)rule->cmd;
return ((char *)cmd - (char *)buf);
}
static void ClearAllFWHoles(struct libalias *la);
#define fw_setfield(la, field, num) \
do { \
(field)[(num) - la->fireWallBaseNum] = 1; \
} /*lint -save -e717 */ while(0)/* lint -restore */
#define fw_clrfield(la, field, num) \
do { \
(field)[(num) - la->fireWallBaseNum] = 0; \
} /*lint -save -e717 */ while(0)/* lint -restore */
#define fw_tstfield(la, field, num) ((field)[(num) - la->fireWallBaseNum])
static void
InitPunchFW(struct libalias *la)
{
la->fireWallField = malloc(la->fireWallNumNums);
if (la->fireWallField) {
memset(la->fireWallField, 0, la->fireWallNumNums);
if (la->fireWallFD < 0) {
la->fireWallFD = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
}
ClearAllFWHoles(la);
la->fireWallActiveNum = la->fireWallBaseNum;
}
}
static void
UninitPunchFW(struct libalias *la)
{
ClearAllFWHoles(la);
if (la->fireWallFD >= 0)
close(la->fireWallFD);
la->fireWallFD = -1;
if (la->fireWallField)
free(la->fireWallField);
la->fireWallField = NULL;
la->packetAliasMode &= ~PKT_ALIAS_PUNCH_FW;
}
/* Make a certain link go through the firewall */
void
PunchFWHole(struct alias_link *lnk)
{
struct libalias *la;
int r; /* Result code */
struct ip_fw rule; /* On-the-fly built rule */
int fwhole; /* Where to punch hole */
la = lnk->la;
/* Don't do anything unless we are asked to */
if (!(la->packetAliasMode & PKT_ALIAS_PUNCH_FW) ||
la->fireWallFD < 0 ||
lnk->link_type != LINK_TCP)
return;
memset(&rule, 0, sizeof rule);
/** Build rule **/
/* Find empty slot */
for (fwhole = la->fireWallActiveNum;
fwhole < la->fireWallBaseNum + la->fireWallNumNums &&
fw_tstfield(la, la->fireWallField, fwhole);
fwhole++);
if (fwhole == la->fireWallBaseNum + la->fireWallNumNums) {
for (fwhole = la->fireWallBaseNum;
fwhole < la->fireWallActiveNum &&
fw_tstfield(la, la->fireWallField, fwhole);
fwhole++);
if (fwhole == la->fireWallActiveNum) {
/* No rule point empty - we can't punch more holes. */
la->fireWallActiveNum = la->fireWallBaseNum;
#ifdef LIBALIAS_DEBUG
fprintf(stderr, "libalias: Unable to create firewall hole!\n");
#endif
return;
}
}
/* Start next search at next position */
la->fireWallActiveNum = fwhole + 1;
/*
* generate two rules of the form
*
* add fwhole accept tcp from OAddr OPort to DAddr DPort add fwhole
* accept tcp from DAddr DPort to OAddr OPort
*/
if (GetOriginalPort(lnk) != 0 && GetDestPort(lnk) != 0) {
u_int32_t rulebuf[255];
int i;
i = fill_rule(rulebuf, sizeof(rulebuf), fwhole,
O_ACCEPT, IPPROTO_TCP,
GetOriginalAddress(lnk), ntohs(GetOriginalPort(lnk)),
GetDestAddress(lnk), ntohs(GetDestPort(lnk)));
r = setsockopt(la->fireWallFD, IPPROTO_IP, IP_FW_ADD, rulebuf, i);
if (r)
err(1, "alias punch inbound(1) setsockopt(IP_FW_ADD)");
i = fill_rule(rulebuf, sizeof(rulebuf), fwhole,
O_ACCEPT, IPPROTO_TCP,
GetDestAddress(lnk), ntohs(GetDestPort(lnk)),
GetOriginalAddress(lnk), ntohs(GetOriginalPort(lnk)));
r = setsockopt(la->fireWallFD, IPPROTO_IP, IP_FW_ADD, rulebuf, i);
if (r)
err(1, "alias punch inbound(2) setsockopt(IP_FW_ADD)");
}
/* Indicate hole applied */
lnk->data.tcp->fwhole = fwhole;
fw_setfield(la, la->fireWallField, fwhole);
}
/* Remove a hole in a firewall associated with a particular alias
lnk. Calling this too often is harmless. */
static void
ClearFWHole(struct alias_link *lnk)
{
struct libalias *la;
la = lnk->la;
if (lnk->link_type == LINK_TCP) {
int fwhole = lnk->data.tcp->fwhole; /* Where is the firewall hole? */
struct ip_fw rule;
if (fwhole < 0)
return;
memset(&rule, 0, sizeof rule); /* useless for ipfw2 */
while (!setsockopt(la->fireWallFD, IPPROTO_IP, IP_FW_DEL,
&fwhole, sizeof fwhole));
fw_clrfield(la, la->fireWallField, fwhole);
lnk->data.tcp->fwhole = -1;
}
}
/* Clear out the entire range dedicated to firewall holes. */
static void
ClearAllFWHoles(struct libalias *la)
{
struct ip_fw rule; /* On-the-fly built rule */
int i;
if (la->fireWallFD < 0)
return;
memset(&rule, 0, sizeof rule);
for (i = la->fireWallBaseNum; i < la->fireWallBaseNum + la->fireWallNumNums; i++) {
int r = i;
while (!setsockopt(la->fireWallFD, IPPROTO_IP, IP_FW_DEL, &r, sizeof r));
}
/* XXX: third arg correct here ? /phk */
memset(la->fireWallField, 0, la->fireWallNumNums);
}
#endif /* !NO_FW_PUNCH */
void
LibAliasSetFWBase(struct libalias *la, unsigned int base, unsigned int num)
{
LIBALIAS_LOCK(la);
#ifndef NO_FW_PUNCH
la->fireWallBaseNum = base;
la->fireWallNumNums = num;
#endif
LIBALIAS_UNLOCK(la);
}
void
LibAliasSetSkinnyPort(struct libalias *la, unsigned int port)
{
LIBALIAS_LOCK(la);
la->skinnyPort = port;
LIBALIAS_UNLOCK(la);
}
/*
* Find the address to redirect incoming packets
*/
struct in_addr
FindSctpRedirectAddress(struct libalias *la, struct sctp_nat_msg *sm)
{
struct alias_link *lnk;
struct in_addr redir;
LIBALIAS_LOCK_ASSERT(la);
lnk = FindLinkIn(la, sm->ip_hdr->ip_src, sm->ip_hdr->ip_dst,
sm->sctp_hdr->dest_port,sm->sctp_hdr->dest_port, LINK_SCTP, 1);
if (lnk != NULL) {
/* port redirect */
return (lnk->src_addr);
} else {
redir = FindOriginalAddress(la,sm->ip_hdr->ip_dst);
if (redir.s_addr == la->aliasAddress.s_addr ||
redir.s_addr == la->targetAddress.s_addr) {
/* No address found */
lnk = FindLinkIn(la, sm->ip_hdr->ip_src, sm->ip_hdr->ip_dst,
NO_DEST_PORT, 0, LINK_SCTP, 1);
if (lnk != NULL)
/* redirect proto */
return (lnk->src_addr);
}
return (redir); /* address redirect */
}
}
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