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freebsd-dev/sys/netinet/libalias/alias_db.c
Lutz Donnerhacke f284553444 libalias: Fix API bug on initialization 
The kernel part of ipfw(8) does initialize LibAlias uncondistionally
with an zeroized port range (allowed ports from 0 to 0).  During
restucturing of libalias, port ranges are used everytime and are
therefor initialized with different values than zero.  The secondary
initialization from ipfw (and probably others) overrides the new
default values and leave the instance in an unfunctional state.  The
obvious solution is to detect such reinitializations and use the new
default value instead.

MFC after:	3 days
2021-07-03 23:03:07 +02:00

2485 lines
56 KiB
C
Raw Blame History

/*-
* 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("$FreeBSD$");
#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
#include "alias_db.h"
static LIST_HEAD(, libalias) instancehead = LIST_HEAD_INITIALIZER(instancehead);
int LibAliasTime;
/* 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
SPLAY_GENERATE(splay_out, alias_link, all.out, cmp_out);
SPLAY_GENERATE(splay_in, group_in, in, cmp_in);
static struct group_in *
StartPointIn(struct libalias *la,
struct in_addr alias_addr, u_short alias_port, int link_type,
int create)
{
struct group_in *grp;
struct group_in needle = {
.alias_addr = alias_addr,
.alias_port = alias_port,
.link_type = link_type
};
grp = SPLAY_FIND(splay_in, &la->linkSplayIn, &needle);
if (grp != NULL || !create || (grp = malloc(sizeof(*grp))) == NULL)
return (grp);
grp->alias_addr = alias_addr;
grp->alias_port = alias_port;
grp->link_type = link_type;
LIST_INIT(&grp->full);
LIST_INIT(&grp->partial);
SPLAY_INSERT(splay_in, &la->linkSplayIn, grp);
return (grp);
}
#undef INGUARD
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);
}
/* get random port in network byte order */
static u_short
_RandomPort(struct libalias *la) {
u_short port;
port = la->aliasPortLower +
arc4random_uniform(la->aliasPortLength);
return ntohs(port);
}
/* 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;
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.
*
* The aliasing port is automatically selected by one of
* two methods below:
*
* When this parameter is GET_ALIAS_PORT, it indicates to get
* a randomly selected port number.
*/
if (alias_port_param >= 0 && alias_port_param < 0x10000) {
lnk->alias_port = (u_short) alias_port_param;
return (0);
}
if (alias_port_param != GET_ALIAS_PORT) {
#ifdef LIBALIAS_DEBUG
fprintf(stderr, "PacketAlias/GetNewPort(): ");
fprintf(stderr, "input parameter error\n");
#endif
return (-1);
}
max_trials = GET_NEW_PORT_MAX_ATTEMPTS;
/*
* 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 = (la->packetAliasMode & PKT_ALIAS_SAME_PORTS)
? lnk->src_port
: _RandomPort(la);
/* Port number search */
for (i = 0; i < max_trials; i++, port = _RandomPort(la)) {
struct group_in *grp;
struct alias_link *search_result;
grp = StartPointIn(la, lnk->alias_addr, port, lnk->link_type, 0);
if (grp == NULL)
break;
LIST_FOREACH(search_result, &grp->full, all.in) {
if (lnk->dst_addr.s_addr == search_result->dst_addr.s_addr &&
lnk->dst_port == search_result->dst_port)
break; /* found match */
}
if (search_result == NULL)
break;
}
if (i >= max_trials) {
#ifdef LIBALIAS_DEBUG
fprintf(stderr, "PacketAlias/GetNewPort(): ");
fprintf(stderr, "could not find free port\n");
#endif
return (-1);
}
#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, &lnk->sockfd, lnk->link_type)) {
return (-1);
}
}
#endif
lnk->alias_port = port;
return (0);
}
#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;
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 = src_port;
} else {
port = _RandomPort(la);
}
/* Port number search */
for (i = 0; i < max_trials; i++, port = _RandomPort(la)) {
struct alias_link *search_result;
if (align)
port &= htons(0xfffe);
for (j = 0; j < port_count; j++) {
u_short port_j = ntohs(port) + j;
if ((search_result = FindLinkIn(la, dst_addr,
alias_addr, dst_port, htons(port_j),
link_type, 0)) != NULL)
break;
}
/* Found a good range, return base */
if (j == port_count)
return (port);
}
#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, int deletePermanent)
{
struct alias_link *lnk, *lnk_tmp;
LIBALIAS_LOCK_ASSERT(la);
/* permanent entries may stay */
TAILQ_FOREACH_SAFE(lnk, &la->checkExpire, expire.list, lnk_tmp)
DeleteLink(&lnk, deletePermanent);
}
static void
CleanupLink(struct libalias *la, struct alias_link **lnk, int deletePermanent)
{
LIBALIAS_LOCK_ASSERT(la);
if (lnk == NULL || *lnk == NULL)
return;
if (LibAliasTime - (*lnk)->timestamp > (*lnk)->expire.time) {
DeleteLink(lnk, deletePermanent);
if ((*lnk) == NULL)
return;
}
/* move to end, swap may fail on a single entry list */
TAILQ_REMOVE(&la->checkExpire, (*lnk), expire.list);
TAILQ_INSERT_TAIL(&la->checkExpire, (*lnk), expire.list);
}
static struct alias_link *
UseLink(struct libalias *la, struct alias_link *lnk)
{
CleanupLink(la, &lnk, 0);
if (lnk != NULL)
lnk->timestamp = LibAliasTime;
return (lnk);
}
static void
DeleteLink(struct alias_link **plnk, int deletePermanent)
{
struct alias_link *lnk = *plnk;
struct libalias *la = lnk->la;
LIBALIAS_LOCK_ASSERT(la);
/* Don't do anything if the link is marked permanent */
if (!deletePermanent && (lnk->flags & LINK_PERMANENT))
return;
#ifndef NO_FW_PUNCH
/* Delete associated firewall hole, if any */
ClearFWHole(lnk);
#endif
switch (lnk->link_type) {
case LINK_PPTP:
LIST_REMOVE(lnk, pptp.list);
break;
default: {
struct group_in *grp;
/* 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);
} else {
/* Adjust output table pointers */
SPLAY_REMOVE(splay_out, &la->linkSplayOut, lnk);
}
/* Adjust input table pointers */
LIST_REMOVE(lnk, all.in);
/* Remove intermediate node, if empty */
grp = StartPointIn(la, lnk->alias_addr, lnk->alias_port, lnk->link_type, 0);
if (grp != NULL &&
LIST_EMPTY(&grp->full) &&
LIST_EMPTY(&grp->partial)) {
SPLAY_REMOVE(splay_in, &la->linkSplayIn, grp);
free(grp);
}
}
break;
}
/* remove from housekeeping */
TAILQ_REMOVE(&la->checkExpire, lnk, expire.list);
#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);
*plnk = NULL;
/* 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)
{
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
lnk = malloc(sizeof(struct alias_link));
if (lnk == NULL) {
#ifdef LIBALIAS_DEBUG
fprintf(stderr, "PacketAlias/AddLink(): ");
fprintf(stderr, "malloc() call failed.\n");
#endif
return (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 = LibAliasTime;
/* 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_FRAGMENT_ID:
lnk->expire.time = FRAGMENT_ID_EXPIRE_TIME;
break;
case LINK_FRAGMENT_PTR:
lnk->expire.time = FRAGMENT_PTR_EXPIRE_TIME;
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) {
case LINK_ICMP:
la->icmpLinkCount++;
break;
case LINK_UDP:
la->udpLinkCount++;
break;
case LINK_TCP: {
struct tcp_dat *aux_tcp;
int i;
aux_tcp = malloc(sizeof(struct tcp_dat));
if (aux_tcp == NULL) {
#ifdef LIBALIAS_DEBUG
fprintf(stderr, "PacketAlias/AddLink: ");
fprintf(stderr, " cannot allocate auxiliary TCP data\n");
#endif
free(lnk);
return (NULL);
}
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;
}
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;
}
switch (link_type) {
case LINK_PPTP:
LIST_INSERT_HEAD(&la->pptpList, lnk, pptp.list);
break;
default: {
struct group_in *grp;
grp = StartPointIn(la, alias_addr, lnk->alias_port, link_type, 1);
if (grp == NULL) {
free(lnk);
return (NULL);
}
/* Set up pointers for output lookup table */
SPLAY_INSERT(splay_out, &la->linkSplayOut, lnk);
/* Set up pointers for input lookup table */
if (lnk->flags & LINK_PARTIALLY_SPECIFIED)
LIST_INSERT_HEAD(&grp->partial, lnk, all.in);
else
LIST_INSERT_HEAD(&grp->full, lnk, all.in);
}
break;
}
/* Include the element into the housekeeping list */
TAILQ_INSERT_TAIL(&la->checkExpire, lnk, expire.list);
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,
int deletePermanent)
{
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, deletePermanent);
return (new_lnk);
}
static struct alias_link *
_SearchLinkOut(struct libalias *la, struct in_addr src_addr,
struct in_addr dst_addr,
u_short src_port,
u_short dst_port,
int link_type) {
struct alias_link *lnk;
struct alias_link needle = {
.src_addr = src_addr,
.dst_addr = dst_addr,
.src_port = src_port,
.dst_port = dst_port,
.link_type = link_type
};
lnk = SPLAY_FIND(splay_out, &la->linkSplayOut, &needle);
return (UseLink(la, 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 = _SearchLinkOut(la, src_addr, dst_addr, src_port, dst_port, link_type);
if (lnk != NULL || !replace_partial_links)
return (lnk);
/* Search for partially specified links. */
if (dst_port != 0 && dst_addr.s_addr != INADDR_ANY) {
lnk = _SearchLinkOut(la, src_addr, dst_addr, src_port, 0,
link_type);
if (lnk == NULL)
lnk = _SearchLinkOut(la, src_addr, ANY_ADDR, src_port,
dst_port, link_type);
}
if (lnk == NULL &&
(dst_port != 0 || dst_addr.s_addr != INADDR_ANY)) {
lnk = _SearchLinkOut(la, src_addr, ANY_ADDR, src_port, 0,
link_type);
}
if (lnk != NULL) {
lnk = ReLink(lnk,
src_addr, dst_addr, lnk->alias_addr,
src_port, dst_port, lnk->alias_port,
link_type, 0);
}
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, ANY_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;
struct group_in *grp;
struct alias_link *lnk;
struct alias_link *lnk_unknown_all;
struct alias_link *lnk_unknown_dst_addr;
struct alias_link *lnk_unknown_dst_port;
struct in_addr src_addr;
u_short src_port;
LIBALIAS_LOCK_ASSERT(la);
/* Initialize pointers */
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 */
grp = StartPointIn(la, alias_addr, alias_port, link_type, 0);
if (grp == NULL)
return (NULL);
switch (flags_in) {
case 0:
LIST_FOREACH(lnk, &grp->full, all.in) {
if (lnk->dst_addr.s_addr == dst_addr.s_addr &&
lnk->dst_port == dst_port)
return (UseLink(la, lnk));
}
break;
case LINK_UNKNOWN_DEST_PORT:
LIST_FOREACH(lnk, &grp->full, all.in) {
if(lnk->dst_addr.s_addr == dst_addr.s_addr) {
lnk_unknown_dst_port = lnk;
break;
}
}
break;
case LINK_UNKNOWN_DEST_ADDR:
LIST_FOREACH(lnk, &grp->full, all.in) {
if(lnk->dst_port == dst_port) {
lnk_unknown_dst_addr = lnk;
break;
}
}
break;
case LINK_PARTIALLY_SPECIFIED:
lnk_unknown_all = LIST_FIRST(&grp->full);
break;
}
if (lnk_unknown_dst_port == NULL) {
LIST_FOREACH(lnk, &grp->partial, all.in) {
int flags = (flags_in | lnk->flags) & LINK_PARTIALLY_SPECIFIED;
if (flags == LINK_PARTIALLY_SPECIFIED &&
lnk_unknown_all == NULL)
lnk_unknown_all = lnk;
if (flags == LINK_UNKNOWN_DEST_ADDR &&
lnk->dst_port == dst_port &&
lnk_unknown_dst_addr == NULL)
lnk_unknown_dst_addr = lnk;
if (flags == LINK_UNKNOWN_DEST_PORT &&
lnk->dst_addr.s_addr == dst_addr.s_addr) {
lnk_unknown_dst_port = lnk;
break;
}
}
}
lnk = (lnk_unknown_dst_port != NULL) ? lnk_unknown_dst_port
: (lnk_unknown_dst_addr != NULL) ? lnk_unknown_dst_addr
: lnk_unknown_all;
if (lnk == NULL || !replace_partial_links)
return (lnk);
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;
} else {
lnk = ReLink(lnk,
src_addr, dst_addr, alias_addr,
src_port, dst_port, alias_port,
link_type, 0);
}
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, ANY_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, ANY_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, ANY_ADDR, dst_addr, ANY_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, ANY_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)
{
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
LIST_FOREACH(lnk, &la->pptpList, pptp.list)
if (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 (UseLink(la, lnk));
}
struct alias_link *
FindPptpOutByPeerCallId(struct libalias *la, struct in_addr src_addr,
struct in_addr dst_addr,
u_int16_t dst_call_id)
{
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
LIST_FOREACH(lnk, &la->pptpList, pptp.list)
if (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 (UseLink(la, lnk));
}
struct alias_link *
FindPptpInByCallId(struct libalias *la, struct in_addr dst_addr,
struct in_addr alias_addr,
u_int16_t dst_call_id)
{
struct alias_link *lnk;
LIBALIAS_LOCK_ASSERT(la);
LIST_FOREACH(lnk, &la->pptpList, pptp.list)
if (lnk->dst_port == dst_call_id &&
lnk->dst_addr.s_addr == dst_addr.s_addr &&
lnk->alias_addr.s_addr == alias_addr.s_addr)
break;
return (UseLink(la, 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);
LIST_FOREACH(lnk, &la->pptpList, pptp.list)
if (lnk->alias_port == alias_call_id &&
lnk->dst_addr.s_addr == dst_addr.s_addr &&
lnk->alias_addr.s_addr == alias_addr.s_addr)
break;
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, ANY_ADDR, alias_addr,
0, 0, LINK_ADDR, 0);
if (lnk == NULL) {
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, ANY_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, 0);
} 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
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)
{
LIBALIAS_LOCK_ASSERT(lnk->la);
ReLink(lnk, lnk->src_addr, lnk->dst_addr, lnk->alias_addr,
lnk->src_port, cid, lnk->alias_port, lnk->link_type, 1);
}
/* 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)
{
static unsigned int packets = 0;
static unsigned int packet_limit = 1000;
LIBALIAS_LOCK_ASSERT(la);
packets++;
/*
* User space time/gettimeofday/... is very expensive.
* Kernel space cache trashing is unnecessary.
*
* Save system time (seconds) in global variable LibAliasTime
* for use by other functions. This is done so as not to
* unnecessarily waste timeline by making system calls.
*
* Reduce the amount of house keeping work substantially by
* sampling over the packets.
*/
if (packets % packet_limit == 0) {
time_t now;
#ifdef _KERNEL
now = time_uptime;
#else
now = time(NULL);
#endif
if (now != LibAliasTime) {
/* retry three times a second */
packet_limit = packets / 3;
packets = 0;
LibAliasTime = now;
}
}
/* Do a cleanup for the first packets of the new second only */
if (packets < (la->udpLinkCount + la->tcpLinkCount)) {
struct alias_link * lnk = TAILQ_FIRST(&la->checkExpire);
CleanupLink(la, &lnk, 0);
}
}
/* 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;
switch (lnk->link_type) {
case LINK_PPTP:
server = NULL;
break;
default:
server = malloc(sizeof(struct server));
break;
}
if (server != NULL) {
struct server *head;
server->addr = addr;
server->port = port;
head = lnk->server;
if (head == NULL) {
server->next = server;
/* not usable for outgoing connections */
SPLAY_REMOVE(splay_out, &la->linkSplayOut, lnk);
} 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, ANY_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);
(void)la;
DeleteLink(&lnk, 1);
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, 0);
la->aliasAddress = addr;
LIBALIAS_UNLOCK(la);
}
void
LibAliasSetAliasPortRange(struct libalias *la, u_short port_low,
u_short port_high)
{
LIBALIAS_LOCK(la);
if (port_low) {
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;
} else {
/* Set default values */
la->aliasPortLower = 0x8000;
la->aliasPortLength = 0x8000;
}
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)
{
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
LibAliasTime = time_uptime;
#else
LibAliasTime = time(NULL);
#endif
SPLAY_INIT(&la->linkSplayIn);
SPLAY_INIT(&la->linkSplayOut);
LIST_INIT(&la->pptpList);
TAILQ_INIT(&la->checkExpire);
#ifdef _KERNEL
AliasSctpInit(la);
#endif
LIBALIAS_LOCK_INIT(la);
LIBALIAS_LOCK(la);
} else {
LIBALIAS_LOCK(la);
CleanupAliasData(la, 1);
#ifdef _KERNEL
AliasSctpTerm(la);
AliasSctpInit(la);
#endif
}
la->aliasAddress.s_addr = INADDR_ANY;
la->targetAddress.s_addr = INADDR_ANY;
la->aliasPortLower = 0x8000;
la->aliasPortLength = 0x8000;
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->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
CleanupAliasData(la, 1);
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);
}
#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
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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