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freebsd-skq/sys/netinet/ip_nat.c
eivind 0ab244240a KERNEL -> _KERNEL
2000-01-05 16:25:20 +00:00

1742 lines
41 KiB
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/*
* Copyright (C) 1995-1998 by Darren Reed.
*
* Redistribution and use in source and binary forms are permitted
* provided that this notice is preserved and due credit is given
* to the original author and the contributors.
*
* Added redirect stuff and a LOT of bug fixes. (mcn@EnGarde.com)
*/
#if !defined(lint)
static const char sccsid[] = "@(#)ip_nat.c 1.11 6/5/96 (C) 1995 Darren Reed";
/*static const char rcsid[] = "@(#)$Id: ip_nat.c,v 2.2.2.5 1999/10/05 12:58:33 darrenr Exp $";*/
static const char rcsid[] = "@(#)$FreeBSD$";
#endif
#if defined(__FreeBSD__) && defined(KERNEL) && !defined(_KERNEL)
#define _KERNEL
#endif
#include <sys/errno.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/file.h>
#if defined(__NetBSD__) && (NetBSD >= 199905) && !defined(IPFILTER_LKM) && \
defined(_KERNEL)
# include "opt_ipfilter_log.h"
#endif
#if !defined(_KERNEL) && !defined(KERNEL)
# include <stdio.h>
# include <string.h>
# include <stdlib.h>
#endif
#if defined(_KERNEL) && (__FreeBSD_version >= 220000)
# include <sys/filio.h>
# include <sys/fcntl.h>
#else
# include <sys/ioctl.h>
#endif
#include <sys/fcntl.h>
#include <sys/uio.h>
#ifndef linux
# include <sys/protosw.h>
#endif
#include <sys/socket.h>
#if defined(_KERNEL) && !defined(linux)
# include <sys/systm.h>
#endif
#if !defined(__SVR4) && !defined(__svr4__)
# ifndef linux
# include <sys/mbuf.h>
# endif
#else
# include <sys/filio.h>
# include <sys/byteorder.h>
# ifdef _KERNEL
# include <sys/dditypes.h>
# endif
# include <sys/stream.h>
# include <sys/kmem.h>
#endif
#if __FreeBSD_version >= 300000
# include <sys/queue.h>
#endif
#include <net/if.h>
#if __FreeBSD_version >= 300000
# include <net/if_var.h>
# if defined(_KERNEL) && !defined(IPFILTER_LKM)
# include "opt_ipfilter.h"
# endif
#endif
#ifdef sun
# include <net/af.h>
#endif
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#ifdef __sgi
# ifdef IFF_DRVRLOCK /* IRIX6 */
#include <sys/hashing.h>
#include <netinet/in_var.h>
# endif
#endif
#ifdef RFC1825
# include <vpn/md5.h>
# include <vpn/ipsec.h>
extern struct ifnet vpnif;
#endif
#ifndef linux
# include <netinet/ip_var.h>
#endif
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <netinet/ip_icmp.h>
#include "netinet/ip_compat.h"
#include <netinet/tcpip.h>
#include "netinet/ip_fil.h"
#include "netinet/ip_proxy.h"
#include "netinet/ip_nat.h"
#include "netinet/ip_frag.h"
#include "netinet/ip_state.h"
#if (__FreeBSD_version >= 300000)
# include <sys/malloc.h>
#endif
#ifndef MIN
# define MIN(a,b) (((a)<(b))?(a):(b))
#endif
#undef SOCKADDR_IN
#define SOCKADDR_IN struct sockaddr_in
nat_t **nat_table[2] = { NULL, NULL },
*nat_instances = NULL;
#if (SOLARIS || defined(__sgi)) && defined(_KERNEL)
ipnat_t *nat_list = NULL;
#else
static ipnat_t *nat_list = NULL;
#endif
u_int ipf_nattable_sz = NAT_TABLE_SZ;
u_int ipf_natrules_sz = NAT_SIZE;
u_int ipf_rdrrules_sz = RDR_SIZE;
u_32_t nat_masks = 0;
u_32_t rdr_masks = 0;
ipnat_t **nat_rules = NULL;
ipnat_t **rdr_rules = NULL;
u_long fr_defnatage = DEF_NAT_AGE,
fr_defnaticmpage = 6; /* 3 seconds */
static natstat_t nat_stats;
#if (SOLARIS || defined(__sgi)) && defined(_KERNEL)
extern kmutex_t ipf_rw;
extern KRWLOCK_T ipf_nat;
#endif
static int nat_flushtable __P((void));
static int nat_clearlist __P((void));
static void nat_delete __P((struct nat *));
static void nat_delrdr __P((struct ipnat *));
static void nat_delnat __P((struct ipnat *));
int nat_init()
{
KMALLOCS(nat_table[0], nat_t **, sizeof(nat_t *) * ipf_nattable_sz);
if (nat_table[0] != NULL)
bzero((char *)nat_table[0], ipf_nattable_sz * sizeof(nat_t *));
else
return -1;
KMALLOCS(nat_table[1], nat_t **, sizeof(nat_t *) * ipf_nattable_sz);
if (nat_table[1] != NULL)
bzero((char *)nat_table[1], ipf_nattable_sz * sizeof(nat_t *));
else
return -1;
KMALLOCS(nat_rules, ipnat_t **, sizeof(ipnat_t *) * ipf_natrules_sz);
if (nat_rules != NULL)
bzero((char *)nat_rules, ipf_natrules_sz * sizeof(ipnat_t *));
else
return -1;
KMALLOCS(rdr_rules, ipnat_t **, sizeof(ipnat_t *) * ipf_rdrrules_sz);
if (rdr_rules != NULL)
bzero((char *)rdr_rules, ipf_rdrrules_sz * sizeof(ipnat_t *));
else
return -1;
return 0;
}
void nat_delrdr(n)
ipnat_t *n;
{
ipnat_t **n1;
u_32_t iph;
u_int hv;
iph = n->in_outip & n->in_outmsk;
hv = NAT_HASH_FN(iph, ipf_rdrrules_sz);
for (n1 = &rdr_rules[hv]; *n1 && (*n1 != n); n1 = &(*n1)->in_rnext)
;
if (*n1)
*n1 = n->in_rnext;
}
static void nat_delnat(n)
ipnat_t *n;
{
ipnat_t **n1;
u_32_t iph;
u_int hv;
iph = n->in_inip & n->in_inmsk;
hv = NAT_HASH_FN(iph, ipf_natrules_sz);
for (n1 = &nat_rules[hv]; *n1 && (*n1 != n); n1 = &(*n1)->in_mnext)
;
if (*n1)
*n1 = n->in_mnext;
}
void fix_outcksum(sp, n)
u_short *sp;
u_32_t n;
{
register u_short sumshort;
register u_32_t sum1;
if (!n)
return;
sum1 = (~ntohs(*sp)) & 0xffff;
sum1 += (n);
sum1 = (sum1 >> 16) + (sum1 & 0xffff);
/* Again */
sum1 = (sum1 >> 16) + (sum1 & 0xffff);
sumshort = ~(u_short)sum1;
*(sp) = htons(sumshort);
}
void fix_incksum(sp, n)
u_short *sp;
u_32_t n;
{
register u_short sumshort;
register u_32_t sum1;
if (!n)
return;
#ifdef sparc
sum1 = (~(*sp)) & 0xffff;
#else
sum1 = (~ntohs(*sp)) & 0xffff;
#endif
sum1 += ~(n) & 0xffff;
sum1 = (sum1 >> 16) + (sum1 & 0xffff);
/* Again */
sum1 = (sum1 >> 16) + (sum1 & 0xffff);
sumshort = ~(u_short)sum1;
*(sp) = htons(sumshort);
}
/*
* How the NAT is organised and works.
*
* Inside (interface y) NAT Outside (interface x)
* -------------------- -+- -------------------------------------
* Packet going | out, processsed by ip_natout() for x
* ------------> | ------------>
* src=10.1.1.1 | src=192.1.1.1
* |
* | in, processed by ip_natin() for x
* <------------ | <------------
* dst=10.1.1.1 | dst=192.1.1.1
* -------------------- -+- -------------------------------------
* ip_natout() - changes ip_src and if required, sport
* - creates a new mapping, if required.
* ip_natin() - changes ip_dst and if required, dport
*
* In the NAT table, internal source is recorded as "in" and externally
* seen as "out".
*/
/*
* Handle ioctls which manipulate the NAT.
*/
int nat_ioctl(data, cmd, mode)
#if defined(__NetBSD__) || defined(__OpenBSD__) || (__FreeBSD_version >= 300003)
u_long cmd;
#else
int cmd;
#endif
caddr_t data;
int mode;
{
register ipnat_t *nat, *nt, *n = NULL, **np = NULL;
int error = 0, ret, k;
ipnat_t natd;
u_32_t i, j;
#if defined(_KERNEL) && !SOLARIS
int s;
#endif
#if (BSD >= 199306) && defined(_KERNEL)
if ((securelevel >= 2) && (mode & FWRITE))
return EPERM;
#endif
nat = NULL; /* XXX gcc -Wuninitialized */
KMALLOC(nt, ipnat_t *);
if ((cmd == SIOCADNAT) || (cmd == SIOCRMNAT))
IRCOPY(data, (char *)&natd, sizeof(natd));
/*
* For add/delete, look to see if the NAT entry is already present
*/
SPL_NET(s);
WRITE_ENTER(&ipf_nat);
if ((cmd == SIOCADNAT) || (cmd == SIOCRMNAT)) {
nat = &natd;
nat->in_flags &= IPN_USERFLAGS;
if ((nat->in_redir & NAT_MAPBLK) == 0) {
nat->in_inip &= nat->in_inmsk;
if ((nat->in_flags & IPN_RANGE) == 0)
nat->in_outip &= nat->in_outmsk;
}
for (np = &nat_list; (n = *np); np = &n->in_next)
if (!bcmp((char *)&nat->in_flags, (char *)&n->in_flags,
IPN_CMPSIZ))
break;
}
switch (cmd)
{
case SIOCADNAT :
if (!(mode & FWRITE)) {
error = EPERM;
break;
}
if (n) {
error = EEXIST;
break;
}
if (nt == NULL) {
error = ENOMEM;
break;
}
n = nt;
nt = NULL;
bcopy((char *)nat, (char *)n, sizeof(*n));
n->in_ifp = (void *)GETUNIT(n->in_ifname);
if (!n->in_ifp)
n->in_ifp = (void *)-1;
if (n->in_plabel[0] != '\0') {
n->in_apr = appr_match(n->in_p, n->in_plabel);
if (!n->in_apr) {
error = ENOENT;
break;
}
}
n->in_next = NULL;
*np = n;
if (n->in_redir & NAT_REDIRECT) {
u_int hv;
k = countbits(n->in_outmsk);
if ((k >= 0) && (k != 32))
rdr_masks |= 1 << k;
j = (n->in_outip & n->in_outmsk);
hv = NAT_HASH_FN(j, ipf_rdrrules_sz);
np = rdr_rules + hv;
while (*np != NULL)
np = &(*np)->in_rnext;
n->in_rnext = NULL;
*np = n;
}
if (n->in_redir & (NAT_MAP|NAT_MAPBLK)) {
u_int hv;
k = countbits(n->in_inmsk);
if ((k >= 0) && (k != 32))
nat_masks |= 1 << k;
j = (n->in_inip & n->in_inmsk);
hv = NAT_HASH_FN(j, ipf_natrules_sz);
np = nat_rules + hv;
while (*np != NULL)
np = &(*np)->in_mnext;
n->in_mnext = NULL;
*np = n;
}
n->in_use = 0;
if (n->in_redir & NAT_MAPBLK)
n->in_space = USABLE_PORTS * ~ntohl(n->in_outmsk);
else if (n->in_flags & IPN_AUTOPORTMAP)
n->in_space = USABLE_PORTS * ~ntohl(n->in_inmsk);
else if (n->in_flags & IPN_RANGE)
n->in_space = ntohl(n->in_outmsk) - ntohl(n->in_outip);
else
n->in_space = ~ntohl(n->in_outmsk);
/*
* Calculate the number of valid IP addresses in the output
* mapping range. In all cases, the range is inclusive of
* the start and ending IP addresses.
* If to a CIDR address, lose 2: broadcast + network address
* (so subtract 1)
* If to a range, add one.
* If to a single IP address, set to 1.
*/
if (n->in_space) {
if ((n->in_flags & IPN_RANGE) != 0)
n->in_space += 1;
else
n->in_space -= 1;
} else
n->in_space = 1;
if ((n->in_outmsk != 0xffffffff) && (n->in_outmsk != 0) &&
((n->in_flags & IPN_RANGE) == 0))
n->in_nip = ntohl(n->in_outip) + 1;
else
n->in_nip = ntohl(n->in_outip);
if (n->in_redir & NAT_MAP) {
n->in_pnext = ntohs(n->in_pmin);
/*
* Multiply by the number of ports made available.
*/
if (ntohs(n->in_pmax) >= ntohs(n->in_pmin)) {
n->in_space *= (ntohs(n->in_pmax) -
ntohs(n->in_pmin) + 1);
/*
* Because two different sources can map to
* different destinations but use the same
* local IP#/port #.
* If the result is smaller than in_space, then
* we may have wrapped around 32bits.
*/
i = n->in_inmsk;
if ((i != 0) && (i != 0xffffffff)) {
j = n->in_space * (~ntohl(i) + 1);
if (j >= n->in_space)
n->in_space = j;
else
n->in_space = 0xffffffff;
}
}
/*
* If no protocol is specified, multiple by 256.
*/
if ((n->in_flags & IPN_TCPUDP) == 0) {
j = n->in_space * 256;
if (j >= n->in_space)
n->in_space = j;
else
n->in_space = 0xffffffff;
}
}
/* Otherwise, these fields are preset */
n = NULL;
nat_stats.ns_rules++;
break;
case SIOCRMNAT :
if (!(mode & FWRITE)) {
error = EPERM;
n = NULL;
break;
}
if (!n) {
error = ESRCH;
break;
}
if (n->in_redir & NAT_REDIRECT)
nat_delrdr(n);
if (n->in_redir & (NAT_MAPBLK|NAT_MAP))
nat_delnat(n);
if (nat_list == NULL) {
nat_masks = 0;
rdr_masks = 0;
}
*np = n->in_next;
if (!n->in_use) {
if (n->in_apr)
appr_free(n->in_apr);
KFREE(n);
nat_stats.ns_rules--;
} else {
n->in_flags |= IPN_DELETE;
n->in_next = NULL;
}
n = NULL;
break;
case SIOCGNATS :
MUTEX_DOWNGRADE(&ipf_nat);
nat_stats.ns_table[0] = nat_table[0];
nat_stats.ns_table[1] = nat_table[1];
nat_stats.ns_list = nat_list;
nat_stats.ns_nattab_sz = ipf_nattable_sz;
nat_stats.ns_rultab_sz = ipf_natrules_sz;
nat_stats.ns_rdrtab_sz = ipf_rdrrules_sz;
nat_stats.ns_instances = nat_instances;
nat_stats.ns_apslist = ap_sess_list;
IWCOPY((char *)&nat_stats, (char *)data, sizeof(nat_stats));
break;
case SIOCGNATL :
{
natlookup_t nl;
MUTEX_DOWNGRADE(&ipf_nat);
IRCOPY((char *)data, (char *)&nl, sizeof(nl));
if (nat_lookupredir(&nl)) {
IWCOPY((char *)&nl, (char *)data, sizeof(nl));
} else
error = ESRCH;
break;
}
case SIOCFLNAT :
if (!(mode & FWRITE)) {
error = EPERM;
break;
}
ret = nat_flushtable();
MUTEX_DOWNGRADE(&ipf_nat);
IWCOPY((caddr_t)&ret, data, sizeof(ret));
break;
case SIOCCNATL :
if (!(mode & FWRITE)) {
error = EPERM;
break;
}
ret = nat_clearlist();
MUTEX_DOWNGRADE(&ipf_nat);
IWCOPY((caddr_t)&ret, data, sizeof(ret));
break;
case FIONREAD :
#ifdef IPFILTER_LOG
MUTEX_DOWNGRADE(&ipf_nat);
IWCOPY((caddr_t)&iplused[IPL_LOGNAT], (caddr_t)data,
sizeof(iplused[IPL_LOGNAT]));
#endif
break;
default :
error = EINVAL;
break;
}
RWLOCK_EXIT(&ipf_nat); /* READ/WRITE */
SPL_X(s);
if (nt)
KFREE(nt);
return error;
}
/*
* Delete a nat entry from the various lists and table.
*/
static void nat_delete(natd)
struct nat *natd;
{
register struct nat **natp, *nat;
struct ipnat *ipn;
for (natp = natd->nat_hstart[0]; (nat = *natp);
natp = &nat->nat_hnext[0])
if (nat == natd) {
*natp = nat->nat_hnext[0];
break;
}
for (natp = natd->nat_hstart[1]; (nat = *natp);
natp = &nat->nat_hnext[1])
if (nat == natd) {
*natp = nat->nat_hnext[1];
break;
}
if (natd->nat_fr != NULL) {
ATOMIC_DEC(natd->nat_fr->fr_ref);
}
/*
* If there is an active reference from the nat entry to its parent
* rule, decrement the rule's reference count and free it too if no
* longer being used.
*/
ipn = natd->nat_ptr;
if (ipn != NULL) {
ipn->in_space++;
ipn->in_use--;
if (!ipn->in_use && (ipn->in_flags & IPN_DELETE)) {
if (ipn->in_apr)
appr_free(ipn->in_apr);
KFREE(ipn);
nat_stats.ns_rules--;
}
}
/*
* If there's a fragment table entry too for this nat entry, then
* dereference that as well.
*/
ipfr_forget((void *)natd);
aps_free(natd->nat_aps);
nat_stats.ns_inuse--;
KFREE(natd);
}
/*
* nat_flushtable - clear the NAT table of all mapping entries.
*/
static int nat_flushtable()
{
register nat_t *nat, **natp;
register int j = 0;
/*
* ALL NAT mappings deleted, so lets just make the deletions
* quicker.
*/
if (nat_table[0] != NULL)
bzero((char *)nat_table[0],
sizeof(nat_table[0]) * ipf_nattable_sz);
if (nat_table[1] != NULL)
bzero((char *)nat_table[1],
sizeof(nat_table[1]) * ipf_nattable_sz);
for (natp = &nat_instances; (nat = *natp); ) {
*natp = nat->nat_next;
nat_delete(nat);
j++;
}
nat_stats.ns_inuse = 0;
return j;
}
/*
* nat_clearlist - delete all rules in the active NAT mapping list.
*/
static int nat_clearlist()
{
register ipnat_t *n, **np = &nat_list;
int i = 0;
if (nat_rules != NULL)
bzero((char *)nat_rules, sizeof(*nat_rules) * ipf_natrules_sz);
if (rdr_rules != NULL)
bzero((char *)rdr_rules, sizeof(*rdr_rules) * ipf_rdrrules_sz);
while ((n = *np)) {
*np = n->in_next;
if (!n->in_use) {
if (n->in_apr)
appr_free(n->in_apr);
KFREE(n);
nat_stats.ns_rules--;
} else {
n->in_flags |= IPN_DELETE;
n->in_next = NULL;
}
i++;
}
nat_masks = 0;
rdr_masks = 0;
return i;
}
/*
* Create a new NAT table entry.
* NOTE: assumes write lock on ipf_nat has been obtained already.
*/
nat_t *nat_new(np, ip, fin, flags, direction)
ipnat_t *np;
ip_t *ip;
fr_info_t *fin;
u_int flags;
int direction;
{
register u_32_t sum1, sum2, sumd, l;
u_short port = 0, sport = 0, dport = 0, nport = 0;
nat_t *nat, **natp, *natl = NULL;
struct in_addr in, inb;
tcphdr_t *tcp = NULL;
u_short nflags;
u_int hv;
nflags = flags & np->in_flags;
if (flags & IPN_TCPUDP) {
tcp = (tcphdr_t *)fin->fin_dp;
sport = tcp->th_sport;
dport = tcp->th_dport;
}
/* Give me a new nat */
KMALLOC(nat, nat_t *);
if (nat == NULL)
return NULL;
bzero((char *)nat, sizeof(*nat));
nat->nat_flags = flags;
/*
* Search the current table for a match.
*/
if (direction == NAT_OUTBOUND) {
/*
* Values at which the search for a free resouce starts.
*/
u_32_t st_ip;
u_short st_port;
/*
* If it's an outbound packet which doesn't match any existing
* record, then create a new port
*/
l = 0;
st_ip = np->in_nip;
st_port = np->in_pnext;
do {
port = 0;
in.s_addr = np->in_nip;
if (l == 0) {
natl = nat_maplookup(fin->fin_ifp, flags,
ip->ip_src, ip->ip_dst);
if (natl != NULL) {
in = natl->nat_outip;
#ifndef sparc
in.s_addr = ntohl(in.s_addr);
#endif
}
}
if ((np->in_outmsk == 0xffffffff) &&
(np->in_pnext == 0)) {
if (l > 0) {
KFREE(nat);
return NULL;
}
}
if (np->in_redir & NAT_MAPBLK) {
if ((l >= np->in_ppip) || ((l > 0) &&
!(flags & IPN_TCPUDP))) {
KFREE(nat);
return NULL;
}
/*
* map-block - Calculate destination address.
*/
in.s_addr = ntohl(ip->ip_src.s_addr);
in.s_addr &= ntohl(~np->in_inmsk);
inb.s_addr = in.s_addr;
in.s_addr /= np->in_ippip;
in.s_addr &= ntohl(~np->in_outmsk);
in.s_addr += ntohl(np->in_outip);
/*
* Calculate destination port.
*/
if ((flags & IPN_TCPUDP) &&
(np->in_ppip != 0)) {
port = ntohs(sport) + l;
port %= np->in_ppip;
port += np->in_ppip *
(inb.s_addr % np->in_ippip);
port += MAPBLK_MINPORT;
port = htons(port);
}
} else if (!in.s_addr &&
(np->in_outmsk == 0xffffffff)) {
/*
* 0/32 - use the interface's IP address.
*/
if ((l > 0) ||
fr_ifpaddr(fin->fin_ifp, &in) == -1) {
KFREE(nat);
return NULL;
}
} else if (!in.s_addr && !np->in_outmsk) {
/*
* 0/0 - use the original source address/port.
*/
if (l > 0) {
KFREE(nat);
return NULL;
}
in.s_addr = ntohl(ip->ip_src.s_addr);
} else if ((np->in_outmsk != 0xffffffff) &&
(np->in_pnext == 0) &&
((l > 0) || (natl == NULL)))
np->in_nip++;
natl = NULL;
if ((nflags & IPN_TCPUDP) &&
((np->in_redir & NAT_MAPBLK) == 0) &&
(np->in_flags & IPN_AUTOPORTMAP)) {
if ((l > 0) && (l % np->in_ppip == 0)) {
if (l > np->in_space) {
KFREE(nat);
return NULL;
} else if ((l > np->in_ppip) &&
np->in_outmsk != 0xffffffff)
np->in_nip++;
}
if (np->in_ppip != 0) {
port = ntohs(sport);
port += (l % np->in_ppip);
port %= np->in_ppip;
port += np->in_ppip *
(ntohl(ip->ip_src.s_addr) %
np->in_ippip);
port += MAPBLK_MINPORT;
port = htons(port);
}
} else if (((np->in_redir & NAT_MAPBLK) == 0) &&
(nflags & IPN_TCPUDP) &&
(np->in_pnext != 0)) {
port = htons(np->in_pnext++);
if (np->in_pnext > ntohs(np->in_pmax)) {
np->in_pnext = ntohs(np->in_pmin);
if (np->in_outmsk != 0xffffffff)
np->in_nip++;
}
}
if (np->in_flags & IPN_RANGE) {
if (np->in_nip >= ntohl(np->in_outmsk))
np->in_nip = ntohl(np->in_outip);
} else {
if ((np->in_outmsk != 0xffffffff) &&
((np->in_nip + 1) & ntohl(np->in_outmsk)) >
ntohl(np->in_outip))
np->in_nip = ntohl(np->in_outip) + 1;
}
if (!port && (flags & IPN_TCPUDP))
port = sport;
/*
* Here we do a lookup of the connection as seen from
* the outside. If an IP# pair already exists, try
* again. So if you have A->B becomes C->B, you can
* also have D->E become C->E but not D->B causing
* another C->B. Also take protocol and ports into
* account when determining whether a pre-existing
* NAT setup will cause an external conflict where
* this is appropriate.
*/
inb.s_addr = htonl(in.s_addr);
natl = nat_inlookup(fin->fin_ifp, flags,
(u_int)ip->ip_p, ip->ip_dst, inb,
(port << 16) | dport);
/*
* Has the search wrapped around and come back to the
* start ?
*/
if ((natl != NULL) &&
(np->in_pnext != 0) && (st_port == np->in_pnext) &&
(np->in_nip != 0) && (st_ip == np->in_nip)) {
KFREE(nat);
return NULL;
}
l++;
} while (natl != NULL);
if (np->in_space > 0)
np->in_space--;
/* Setup the NAT table */
nat->nat_inip = ip->ip_src;
nat->nat_outip.s_addr = htonl(in.s_addr);
nat->nat_oip = ip->ip_dst;
sum1 = LONG_SUM(ntohl(ip->ip_src.s_addr)) + ntohs(sport);
sum2 = LONG_SUM(in.s_addr) + ntohs(port);
if (flags & IPN_TCPUDP) {
nat->nat_inport = sport;
nat->nat_outport = port; /* sport */
nat->nat_oport = dport;
}
} else {
/*
* Otherwise, it's an inbound packet. Most likely, we don't
* want to rewrite source ports and source addresses. Instead,
* we want to rewrite to a fixed internal address and fixed
* internal port.
*/
in.s_addr = ntohl(np->in_inip);
if (!(nport = np->in_pnext))
nport = dport;
/*
* When the redirect-to address is set to 0.0.0.0, just
* assume a blank `forwarding' of the packet. We don't
* setup any translation for this either.
*/
if ((in.s_addr == 0) && (nport == dport)) {
KFREE(nat);
return NULL;
}
nat->nat_inip.s_addr = htonl(in.s_addr);
nat->nat_outip = ip->ip_dst;
nat->nat_oip = ip->ip_src;
sum1 = LONG_SUM(ntohl(ip->ip_dst.s_addr)) + ntohs(dport);
sum2 = LONG_SUM(in.s_addr) + ntohs(nport);
if (flags & IPN_TCPUDP) {
nat->nat_inport = nport;
nat->nat_outport = dport;
nat->nat_oport = sport;
}
}
CALC_SUMD(sum1, sum2, sumd);
nat->nat_sumd = (sumd & 0xffff) + (sumd >> 16);
if ((flags & IPN_TCPUDP) && ((sport != port) || (dport != nport))) {
if (direction == NAT_OUTBOUND)
sum1 = LONG_SUM(ntohl(ip->ip_src.s_addr));
else
sum1 = LONG_SUM(ntohl(ip->ip_dst.s_addr));
sum2 = LONG_SUM(in.s_addr);
CALC_SUMD(sum1, sum2, sumd);
nat->nat_ipsumd = (sumd & 0xffff) + (sumd >> 16);
} else
nat->nat_ipsumd = nat->nat_sumd;
in.s_addr = htonl(in.s_addr);
nat->nat_next = nat_instances;
nat_instances = nat;
hv = NAT_HASH_FN(nat->nat_inip.s_addr, ipf_nattable_sz);
natp = &nat_table[0][hv];
nat->nat_hstart[0] = natp;
nat->nat_hnext[0] = *natp;
*natp = nat;
hv = NAT_HASH_FN(nat->nat_outip.s_addr, ipf_nattable_sz);
natp = &nat_table[1][hv];
nat->nat_hstart[1] = natp;
nat->nat_hnext[1] = *natp;
*natp = nat;
nat->nat_dir = direction;
nat->nat_ifp = fin->fin_ifp;
nat->nat_ptr = np;
nat->nat_p = ip->ip_p;
nat->nat_bytes = 0;
nat->nat_pkts = 0;
nat->nat_age = fr_defnatage;
nat->nat_fr = fin->fin_fr;
if (nat->nat_fr != NULL) {
ATOMIC_INC(nat->nat_fr->fr_ref);
}
if (direction == NAT_OUTBOUND) {
if (flags & IPN_TCPUDP)
tcp->th_sport = port;
} else {
if (flags & IPN_TCPUDP)
tcp->th_dport = nport;
}
nat_stats.ns_added++;
nat_stats.ns_inuse++;
np->in_use++;
return nat;
}
nat_t *nat_icmpinlookup(ip, fin)
ip_t *ip;
fr_info_t *fin;
{
icmphdr_t *icmp;
tcphdr_t *tcp = NULL;
ip_t *oip;
int flags = 0, type;
icmp = (icmphdr_t *)fin->fin_dp;
/*
* Does it at least have the return (basic) IP header ?
* Only a basic IP header (no options) should be with an ICMP error
* header.
*/
if ((ip->ip_hl != 5) || (ip->ip_len < ICMPERR_MINPKTLEN))
return NULL;
type = icmp->icmp_type;
/*
* If it's not an error type, then return.
*/
if ((type != ICMP_UNREACH) && (type != ICMP_SOURCEQUENCH) &&
(type != ICMP_REDIRECT) && (type != ICMP_TIMXCEED) &&
(type != ICMP_PARAMPROB))
return NULL;
oip = (ip_t *)((char *)fin->fin_dp + 8);
if (ip->ip_len < ICMPERR_MAXPKTLEN + ((oip->ip_hl - 5) << 2))
return NULL;
if (oip->ip_p == IPPROTO_TCP)
flags = IPN_TCP;
else if (oip->ip_p == IPPROTO_UDP)
flags = IPN_UDP;
if (flags & IPN_TCPUDP) {
tcp = (tcphdr_t *)((char *)oip + (oip->ip_hl << 2));
return nat_inlookup(fin->fin_ifp, flags, (u_int)oip->ip_p,
oip->ip_dst, oip->ip_src,
(tcp->th_sport << 16) | tcp->th_dport);
}
return nat_inlookup(fin->fin_ifp, 0, (u_int)oip->ip_p, oip->ip_dst,
oip->ip_src, 0);
}
/*
* This should *ONLY* be used for incoming packets to make sure a NAT'd ICMP
* packet gets correctly recognised.
*/
nat_t *nat_icmpin(ip, fin, nflags)
ip_t *ip;
fr_info_t *fin;
u_int *nflags;
{
u_32_t sum1, sum2, sumd;
struct in_addr in;
icmphdr_t *icmp;
nat_t *nat;
ip_t *oip;
int flags = 0;
if (!(nat = nat_icmpinlookup(ip, fin)))
return NULL;
*nflags = IPN_ICMPERR;
icmp = (icmphdr_t *)fin->fin_dp;
oip = (ip_t *)&icmp->icmp_ip;
if (oip->ip_p == IPPROTO_TCP)
flags = IPN_TCP;
else if (oip->ip_p == IPPROTO_UDP)
flags = IPN_UDP;
/*
* Need to adjust ICMP header to include the real IP#'s and
* port #'s. Only apply a checksum change relative to the
* IP address change is it will be modified again in ip_natout
* for both address and port. Two checksum changes are
* necessary for the two header address changes. Be careful
* to only modify the checksum once for the port # and twice
* for the IP#.
*/
if (nat->nat_dir == NAT_OUTBOUND) {
sum1 = LONG_SUM(ntohl(oip->ip_src.s_addr));
in = nat->nat_inip;
oip->ip_src = in;
} else {
sum1 = LONG_SUM(ntohl(oip->ip_dst.s_addr));
in = nat->nat_outip;
oip->ip_dst = in;
}
sum2 = LONG_SUM(ntohl(in.s_addr));
CALC_SUMD(sum1, sum2, sumd);
if (nat->nat_dir == NAT_OUTBOUND) {
fix_incksum(&oip->ip_sum, sumd);
sumd += (sumd & 0xffff);
while (sumd > 0xffff)
sumd = (sumd & 0xffff) + (sumd >> 16);
fix_outcksum(&icmp->icmp_cksum, sumd);
} else {
fix_outcksum(&oip->ip_sum, sumd);
sumd += (sumd & 0xffff);
while (sumd > 0xffff)
sumd = (sumd & 0xffff) + (sumd >> 16);
fix_incksum(&icmp->icmp_cksum, sumd);
}
if ((flags & IPN_TCPUDP) != 0) {
tcphdr_t *tcp;
/* XXX - what if this is bogus hl and we go off the end ? */
tcp = (tcphdr_t *)((((char *)oip) + (oip->ip_hl << 2)));
if (nat->nat_dir == NAT_OUTBOUND) {
if (tcp->th_sport != nat->nat_inport) {
sum1 = ntohs(tcp->th_sport);
sum2 = ntohs(nat->nat_inport);
CALC_SUMD(sum1, sum2, sumd);
tcp->th_sport = nat->nat_inport;
fix_outcksum(&icmp->icmp_cksum, sumd);
}
} else {
if (tcp->th_dport != nat->nat_outport) {
sum1 = ntohs(tcp->th_dport);
sum2 = ntohs(nat->nat_outport);
CALC_SUMD(sum1, sum2, sumd);
tcp->th_dport = nat->nat_outport;
fix_incksum(&icmp->icmp_cksum, sumd);
}
}
}
nat->nat_age = fr_defnaticmpage;
return nat;
}
/*
* NB: these lookups don't lock access to the list, it assume it has already
* been done!
*/
/*
* Lookup a nat entry based on the mapped destination ip address/port and
* real source address/port. We use this lookup when receiving a packet,
* we're looking for a table entry, based on the destination address.
* NOTE: THE PACKET BEING CHECKED (IF FOUND) HAS A MAPPING ALREADY.
*/
nat_t *nat_inlookup(ifp, flags, p, src, mapdst, ports)
void *ifp;
register u_int flags, p;
struct in_addr src , mapdst;
u_32_t ports;
{
register u_short sport, mapdport;
register nat_t *nat;
register int nflags;
u_int hv;
mapdport = ports >> 16;
sport = ports & 0xffff;
flags &= IPN_TCPUDP;
hv = NAT_HASH_FN(mapdst.s_addr, ipf_nattable_sz);
nat = nat_table[1][hv];
for (; nat; nat = nat->nat_hnext[1]) {
nflags = nat->nat_flags;
if ((!ifp || ifp == nat->nat_ifp) &&
nat->nat_oip.s_addr == src.s_addr &&
nat->nat_outip.s_addr == mapdst.s_addr &&
(((p == 0) && (flags == (nat->nat_flags & IPN_TCPUDP)))
|| (p == nat->nat_p)) && (!flags ||
(((nat->nat_oport == sport) || (nflags & FI_W_DPORT)) &&
((nat->nat_outport == mapdport) ||
(nflags & FI_W_SPORT)))))
return nat;
}
return NULL;
}
/*
* Lookup a nat entry based on the source 'real' ip address/port and
* destination address/port. We use this lookup when sending a packet out,
* we're looking for a table entry, based on the source address.
* NOTE: THE PACKET BEING CHECKED (IF FOUND) HAS A MAPPING ALREADY.
*/
nat_t *nat_outlookup(ifp, flags, p, src, dst, ports)
void *ifp;
register u_int flags, p;
struct in_addr src , dst;
u_32_t ports;
{
register u_short sport, dport;
register nat_t *nat;
register int nflags;
u_int hv;
sport = ports & 0xffff;
dport = ports >> 16;
flags &= IPN_TCPUDP;
hv = NAT_HASH_FN(src.s_addr, ipf_nattable_sz);
nat = nat_table[0][hv];
for (; nat; nat = nat->nat_hnext[0]) {
nflags = nat->nat_flags;
if ((!ifp || ifp == nat->nat_ifp) &&
nat->nat_inip.s_addr == src.s_addr &&
nat->nat_oip.s_addr == dst.s_addr &&
(((p == 0) && (flags == (nat->nat_flags & IPN_TCPUDP)))
|| (p == nat->nat_p)) && (!flags ||
((nat->nat_inport == sport || nflags & FI_W_SPORT) &&
(nat->nat_oport == dport || nflags & FI_W_DPORT))))
return nat;
}
return NULL;
}
/*
* check if an ip address has already been allocated for a given mapping that
* is not doing port based translation.
*/
nat_t *nat_maplookup(ifp, flags, src, dst)
void *ifp;
register u_int flags;
struct in_addr src , dst;
{
register nat_t *nat;
register int oflags;
u_int hv;
hv = NAT_HASH_FN(src.s_addr, ipf_nattable_sz);
nat = nat_table[0][hv];
for (; nat; nat = nat->nat_hnext[0]) {
oflags = (flags & IPN_TCPUDP) & nat->nat_ptr->in_flags;
if (oflags != 0)
continue;
if ((!ifp || ifp == nat->nat_ifp) &&
nat->nat_inip.s_addr == src.s_addr &&
nat->nat_oip.s_addr == dst.s_addr)
return nat;
}
return NULL;
}
/*
* Lookup the NAT tables to search for a matching redirect
*/
nat_t *nat_lookupredir(np)
register natlookup_t *np;
{
u_32_t ports;
nat_t *nat;
ports = (np->nl_outport << 16) | np->nl_inport;
/*
* If nl_inip is non null, this is a lookup based on the real
* ip address. Else, we use the fake.
*/
if ((nat = nat_outlookup(NULL, np->nl_flags, 0, np->nl_inip,
np->nl_outip, ports))) {
np->nl_realip = nat->nat_outip;
np->nl_realport = nat->nat_outport;
}
return nat;
}
/*
* Packets going out on the external interface go through this.
* Here, the source address requires alteration, if anything.
*/
int ip_natout(ip, fin)
ip_t *ip;
fr_info_t *fin;
{
register ipnat_t *np = NULL;
register u_32_t ipa;
tcphdr_t *tcp = NULL;
u_short nflags = 0, sport = 0, dport = 0, *csump = NULL;
struct ifnet *ifp;
int natadd = 1;
frentry_t *fr;
u_int hv, msk;
u_32_t iph;
nat_t *nat;
int i;
if (nat_list == NULL)
return 0;
if ((fr = fin->fin_fr) && !(fr->fr_flags & FR_DUP) &&
fr->fr_tif.fd_ifp && fr->fr_tif.fd_ifp != (void *)-1)
ifp = fr->fr_tif.fd_ifp;
else
ifp = fin->fin_ifp;
if (!(ip->ip_off & IP_OFFMASK) && !(fin->fin_fi.fi_fl & FI_SHORT)) {
if (ip->ip_p == IPPROTO_TCP)
nflags = IPN_TCP;
else if (ip->ip_p == IPPROTO_UDP)
nflags = IPN_UDP;
if ((nflags & IPN_TCPUDP)) {
tcp = (tcphdr_t *)fin->fin_dp;
sport = tcp->th_sport;
dport = tcp->th_dport;
}
}
ipa = ip->ip_src.s_addr;
READ_ENTER(&ipf_nat);
if ((ip->ip_off & (IP_OFFMASK|IP_MF)) &&
(nat = ipfr_nat_knownfrag(ip, fin)))
natadd = 0;
else if ((nat = nat_outlookup(ifp, nflags, (u_int)ip->ip_p, ip->ip_src,
ip->ip_dst, (dport << 16) | sport))) {
nflags = nat->nat_flags;
if ((nflags & (FI_W_SPORT|FI_W_DPORT)) != 0) {
if ((nflags & FI_W_SPORT) &&
(nat->nat_inport != sport))
nat->nat_inport = sport;
else if ((nflags & FI_W_DPORT) &&
(nat->nat_oport != dport))
nat->nat_oport = dport;
if (nat->nat_outport == 0)
nat->nat_outport = sport;
nat->nat_flags &= ~(FI_W_DPORT|FI_W_SPORT);
nflags = nat->nat_flags;
}
} else {
RWLOCK_EXIT(&ipf_nat);
WRITE_ENTER(&ipf_nat);
/*
* If there is no current entry in the nat table for this IP#,
* create one for it (if there is a matching rule).
*/
msk = 0xffffffff;
i = 32;
maskloop:
iph = ipa & htonl(msk);
hv = NAT_HASH_FN(iph, ipf_natrules_sz);
for (np = nat_rules[hv]; np; np = np->in_mnext)
{
if ((np->in_ifp == ifp) && np->in_space &&
(!(np->in_flags & IPN_RF) ||
(np->in_flags & nflags)) &&
((ipa & np->in_inmsk) == np->in_inip) &&
((np->in_redir & (NAT_MAP|NAT_MAPBLK)) ||
(np->in_pnext == sport))) {
if (*np->in_plabel && !appr_ok(ip, tcp, np))
continue;
/*
* If it's a redirection, then we don't want to
* create new outgoing port stuff.
* Redirections are only for incoming
* connections.
*/
if (!(np->in_redir & (NAT_MAP|NAT_MAPBLK)))
continue;
if ((nat = nat_new(np, ip, fin, (u_int)nflags,
NAT_OUTBOUND))) {
np->in_hits++;
#ifdef IPFILTER_LOG
nat_log(nat, (u_int)np->in_redir);
#endif
break;
}
}
}
if ((np == NULL) && (i > 0)) {
do {
i--;
msk <<= 1;
} while ((i >= 0) && ((nat_masks & (1 << i)) == 0));
if (i >= 0)
goto maskloop;
}
MUTEX_DOWNGRADE(&ipf_nat);
}
if (nat) {
np = nat->nat_ptr;
if (natadd && fin->fin_fi.fi_fl & FI_FRAG)
ipfr_nat_newfrag(ip, fin, 0, nat);
ip->ip_src = nat->nat_outip;
MUTEX_ENTER(&ipf_rw);
nat->nat_age = fr_defnatage;
nat->nat_bytes += ip->ip_len;
nat->nat_pkts++;
MUTEX_EXIT(&ipf_rw);
/*
* Fix up checksums, not by recalculating them, but
* simply computing adjustments.
*/
#if SOLARIS || defined(__sgi)
if (nat->nat_dir == NAT_OUTBOUND)
fix_outcksum(&ip->ip_sum, nat->nat_ipsumd);
else
fix_incksum(&ip->ip_sum, nat->nat_ipsumd);
#endif
if (!(ip->ip_off & IP_OFFMASK) &&
!(fin->fin_fi.fi_fl & FI_SHORT)) {
if ((nat->nat_outport != 0) && (nflags & IPN_TCPUDP)) {
tcp->th_sport = nat->nat_outport;
fin->fin_data[0] = ntohs(tcp->th_sport);
}
if (ip->ip_p == IPPROTO_TCP) {
csump = &tcp->th_sum;
MUTEX_ENTER(&ipf_rw);
fr_tcp_age(&nat->nat_age,
nat->nat_tcpstate, ip, fin, 1);
if (nat->nat_age < fr_defnaticmpage)
nat->nat_age = fr_defnaticmpage;
#ifdef LARGE_NAT
else if (nat->nat_age > DEF_NAT_AGE)
nat->nat_age = DEF_NAT_AGE;
#endif
/*
* Increase this because we may have
* "keep state" following this too and
* packet storms can occur if this is
* removed too quickly.
*/
if (nat->nat_age == fr_tcpclosed)
nat->nat_age = fr_tcplastack;
MUTEX_EXIT(&ipf_rw);
} else if (ip->ip_p == IPPROTO_UDP) {
udphdr_t *udp = (udphdr_t *)tcp;
if (udp->uh_sum)
csump = &udp->uh_sum;
}
if (csump) {
if (nat->nat_dir == NAT_OUTBOUND)
fix_outcksum(csump, nat->nat_sumd);
else
fix_incksum(csump, nat->nat_sumd);
}
}
if ((np->in_apr != NULL) && (np->in_dport == 0 ||
(tcp != NULL && dport == np->in_dport)))
(void) appr_check(ip, fin, nat);
ATOMIC_INC(nat_stats.ns_mapped[1]);
RWLOCK_EXIT(&ipf_nat); /* READ */
return 1;
}
RWLOCK_EXIT(&ipf_nat); /* READ/WRITE */
return 0;
}
/*
* Packets coming in from the external interface go through this.
* Here, the destination address requires alteration, if anything.
*/
int ip_natin(ip, fin)
ip_t *ip;
fr_info_t *fin;
{
register struct in_addr src;
register struct in_addr in;
register ipnat_t *np;
u_int nflags = 0, natadd = 1, hv, msk;
struct ifnet *ifp = fin->fin_ifp;
tcphdr_t *tcp = NULL;
u_short sport = 0, dport = 0, *csump = NULL;
nat_t *nat;
u_32_t iph;
int i;
if (nat_list == NULL)
return 0;
if (!(ip->ip_off & IP_OFFMASK) && !(fin->fin_fi.fi_fl & FI_SHORT)) {
if (ip->ip_p == IPPROTO_TCP)
nflags = IPN_TCP;
else if (ip->ip_p == IPPROTO_UDP)
nflags = IPN_UDP;
if ((nflags & IPN_TCPUDP)) {
tcp = (tcphdr_t *)fin->fin_dp;
dport = tcp->th_dport;
sport = tcp->th_sport;
}
}
in = ip->ip_dst;
/* make sure the source address is to be redirected */
src = ip->ip_src;
READ_ENTER(&ipf_nat);
if ((ip->ip_p == IPPROTO_ICMP) && (nat = nat_icmpin(ip, fin, &nflags)))
;
else if ((ip->ip_off & IP_OFFMASK) &&
(nat = ipfr_nat_knownfrag(ip, fin)))
natadd = 0;
else if ((nat = nat_inlookup(fin->fin_ifp, nflags, (u_int)ip->ip_p,
ip->ip_src, in, (dport << 16) | sport))) {
nflags = nat->nat_flags;
if ((nflags & (FI_W_SPORT|FI_W_DPORT)) != 0) {
if ((nat->nat_oport != sport) && (nflags & FI_W_DPORT))
nat->nat_oport = sport;
else if ((nat->nat_outport != dport) &&
(nflags & FI_W_SPORT))
nat->nat_outport = dport;
nat->nat_flags &= ~(FI_W_SPORT|FI_W_DPORT);
nflags = nat->nat_flags;
}
} else {
RWLOCK_EXIT(&ipf_nat);
WRITE_ENTER(&ipf_nat);
/*
* If there is no current entry in the nat table for this IP#,
* create one for it (if there is a matching rule).
*/
msk = 0xffffffff;
i = 32;
maskloop:
iph = in.s_addr & htonl(msk);
hv = NAT_HASH_FN(iph, ipf_rdrrules_sz);
for (np = rdr_rules[hv]; np; np = np->in_rnext)
if ((np->in_ifp == ifp) &&
(!np->in_flags || (nflags & np->in_flags)) &&
((in.s_addr & np->in_outmsk) == np->in_outip) &&
((src.s_addr & np->in_srcmsk) == np->in_srcip) &&
(np->in_redir & NAT_REDIRECT) &&
(!np->in_pmin || np->in_pmin == dport)) {
if ((nat = nat_new(np, ip, fin, nflags,
NAT_INBOUND))) {
np->in_hits++;
#ifdef IPFILTER_LOG
nat_log(nat, (u_int)np->in_redir);
#endif
break;
}
}
if ((np == NULL) && (i > 0)) {
do {
i--;
msk <<= 1;
} while ((i >= 0) && ((rdr_masks & (1 << i)) == 0));
if (i >= 0)
goto maskloop;
}
MUTEX_DOWNGRADE(&ipf_nat);
}
if (nat) {
np = nat->nat_ptr;
fin->fin_fr = nat->nat_fr;
if (natadd && fin->fin_fi.fi_fl & FI_FRAG)
ipfr_nat_newfrag(ip, fin, 0, nat);
if ((np->in_apr != NULL) && (np->in_dport == 0 ||
(tcp != NULL && sport == np->in_dport)))
(void) appr_check(ip, fin, nat);
MUTEX_ENTER(&ipf_rw);
if (nflags != IPN_ICMPERR)
nat->nat_age = fr_defnatage;
nat->nat_bytes += ip->ip_len;
nat->nat_pkts++;
MUTEX_EXIT(&ipf_rw);
ip->ip_dst = nat->nat_inip;
fin->fin_fi.fi_dst = nat->nat_inip;
/*
* Fix up checksums, not by recalculating them, but
* simply computing adjustments.
*/
#if SOLARIS || defined(__sgi)
if (nat->nat_dir == NAT_OUTBOUND)
fix_incksum(&ip->ip_sum, nat->nat_ipsumd);
else
fix_outcksum(&ip->ip_sum, nat->nat_ipsumd);
#endif
if (!(ip->ip_off & IP_OFFMASK) &&
!(fin->fin_fi.fi_fl & FI_SHORT)) {
if ((nat->nat_inport != 0) && (nflags & IPN_TCPUDP)) {
tcp->th_dport = nat->nat_inport;
fin->fin_data[1] = ntohs(tcp->th_dport);
}
if (ip->ip_p == IPPROTO_TCP) {
csump = &tcp->th_sum;
MUTEX_ENTER(&ipf_rw);
fr_tcp_age(&nat->nat_age,
nat->nat_tcpstate, ip, fin, 0);
if (nat->nat_age < fr_defnaticmpage)
nat->nat_age = fr_defnaticmpage;
#ifdef LARGE_NAT
else if (nat->nat_age > DEF_NAT_AGE)
nat->nat_age = DEF_NAT_AGE;
#endif
/*
* Increase this because we may have
* "keep state" following this too and
* packet storms can occur if this is
* removed too quickly.
*/
if (nat->nat_age == fr_tcpclosed)
nat->nat_age = fr_tcplastack;
MUTEX_EXIT(&ipf_rw);
} else if (ip->ip_p == IPPROTO_UDP) {
udphdr_t *udp = (udphdr_t *)tcp;
if (udp->uh_sum)
csump = &udp->uh_sum;
}
if (csump) {
if (nat->nat_dir == NAT_OUTBOUND)
fix_incksum(csump, nat->nat_sumd);
else
fix_outcksum(csump, nat->nat_sumd);
}
}
ATOMIC_INC(nat_stats.ns_mapped[0]);
RWLOCK_EXIT(&ipf_nat); /* READ */
return 1;
}
RWLOCK_EXIT(&ipf_nat); /* READ/WRITE */
return 0;
}
/*
* Free all memory used by NAT structures allocated at runtime.
*/
void ip_natunload()
{
WRITE_ENTER(&ipf_nat);
(void) nat_clearlist();
(void) nat_flushtable();
RWLOCK_EXIT(&ipf_nat);
if (nat_table[0] != NULL) {
KFREES(nat_table[0], sizeof(nat_t *) * ipf_nattable_sz);
nat_table[0] = NULL;
}
if (nat_table[1] != NULL) {
KFREES(nat_table[1], sizeof(nat_t *) * ipf_nattable_sz);
nat_table[1] = NULL;
}
if (nat_rules != NULL) {
KFREES(nat_rules, sizeof(ipnat_t *) * ipf_natrules_sz);
nat_rules = NULL;
}
if (rdr_rules != NULL) {
KFREES(rdr_rules, sizeof(ipnat_t *) * ipf_rdrrules_sz);
rdr_rules = NULL;
}
}
/*
* Slowly expire held state for NAT entries. Timeouts are set in
* expectation of this being called twice per second.
*/
void ip_natexpire()
{
register struct nat *nat, **natp;
#if defined(_KERNEL) && !SOLARIS
int s;
#endif
SPL_NET(s);
WRITE_ENTER(&ipf_nat);
for (natp = &nat_instances; (nat = *natp); ) {
nat->nat_age--;
if (nat->nat_age) {
natp = &nat->nat_next;
continue;
}
*natp = nat->nat_next;
#ifdef IPFILTER_LOG
nat_log(nat, NL_EXPIRE);
#endif
nat_delete(nat);
nat_stats.ns_expire++;
}
RWLOCK_EXIT(&ipf_nat);
SPL_X(s);
}
/*
*/
void ip_natsync(ifp)
void *ifp;
{
register ipnat_t *n;
register nat_t *nat;
register u_32_t sum1, sum2, sumd;
struct in_addr in;
ipnat_t *np;
void *ifp2;
#if defined(_KERNEL) && !SOLARIS
int s;
#endif
/*
* Change IP addresses for NAT sessions for any protocol except TCP
* since it will break the TCP connection anyway.
*/
SPL_NET(s);
WRITE_ENTER(&ipf_nat);
for (nat = nat_instances; nat; nat = nat->nat_next)
if (((ifp == NULL) || (ifp == nat->nat_ifp)) &&
!(nat->nat_flags & IPN_TCP) && (np = nat->nat_ptr) &&
(np->in_outmsk == 0xffffffff) && !np->in_nip) {
ifp2 = nat->nat_ifp;
/*
* Change the map-to address to be the same as the
* new one.
*/
sum1 = nat->nat_outip.s_addr;
if (fr_ifpaddr(ifp2, &in) != -1)
nat->nat_outip.s_addr = htonl(in.s_addr);
sum2 = nat->nat_outip.s_addr;
if (sum1 == sum2)
continue;
/*
* Readjust the checksum adjustment to take into
* account the new IP#.
*/
CALC_SUMD(sum1, sum2, sumd);
sumd += nat->nat_sumd;
nat->nat_sumd = (sumd & 0xffff) + (sumd >> 16);
}
for (n = nat_list; (n != NULL); n = n->in_next)
if (n->in_ifp == ifp)
n->in_ifp = (void *)GETUNIT(n->in_ifname);
RWLOCK_EXIT(&ipf_nat);
SPL_X(s);
}
#ifdef IPFILTER_LOG
void nat_log(nat, type)
struct nat *nat;
u_int type;
{
struct ipnat *np;
struct natlog natl;
void *items[1];
size_t sizes[1];
int rulen, types[1];
natl.nl_inip = nat->nat_inip;
natl.nl_outip = nat->nat_outip;
natl.nl_origip = nat->nat_oip;
natl.nl_bytes = nat->nat_bytes;
natl.nl_pkts = nat->nat_pkts;
natl.nl_origport = nat->nat_oport;
natl.nl_inport = nat->nat_inport;
natl.nl_outport = nat->nat_outport;
natl.nl_type = type;
natl.nl_rule = -1;
#ifndef LARGE_NAT
if (nat->nat_ptr != NULL) {
for (rulen = 0, np = nat_list; np; np = np->in_next, rulen++)
if (np == nat->nat_ptr) {
natl.nl_rule = rulen;
break;
}
}
#endif
items[0] = &natl;
sizes[0] = sizeof(natl);
types[0] = 0;
(void) ipllog(IPL_LOGNAT, NULL, items, sizes, types, 1);
}
#endif
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