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NetBSD/sys/dist/ipf/netinet/ip_state.c

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/* $NetBSD: ip_state.c,v 1.7 2005/04/03 15:05:30 martti Exp $ */
/*
* Copyright (C) 1995-2003 by Darren Reed.
*
* See the IPFILTER.LICENCE file for details on licencing.
*/
#if defined(KERNEL) || defined(_KERNEL)
# undef KERNEL
# undef _KERNEL
# define KERNEL 1
# define _KERNEL 1
#endif
#include <sys/errno.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/file.h>
#if defined(__NetBSD__) && (NetBSD >= 199905) && !defined(IPFILTER_LKM) && \
defined(_KERNEL)
# include "opt_ipfilter.h"
#endif
#if defined(_KERNEL) && defined(__FreeBSD_version) && \
(__FreeBSD_version >= 400000) && !defined(KLD_MODULE)
#include "opt_inet6.h"
#endif
#if !defined(_KERNEL) && !defined(__KERNEL__)
# include <stdio.h>
# include <stdlib.h>
# include <string.h>
# define _KERNEL
# ifdef __OpenBSD__
struct file;
# endif
# include <sys/uio.h>
# undef _KERNEL
#endif
#if defined(_KERNEL) && (__FreeBSD_version >= 220000)
# include <sys/filio.h>
# include <sys/fcntl.h>
# if (__FreeBSD_version >= 300000) && !defined(IPFILTER_LKM)
# include "opt_ipfilter.h"
# endif
#else
# include <sys/ioctl.h>
#endif
#include <sys/time.h>
#if !defined(linux)
# include <sys/protosw.h>
#endif
#include <sys/socket.h>
#if defined(_KERNEL)
# include <sys/systm.h>
# if !defined(__SVR4) && !defined(__svr4__)
# include <sys/mbuf.h>
# endif
#endif
#if defined(__SVR4) || defined(__svr4__)
# include <sys/filio.h>
# include <sys/byteorder.h>
# ifdef _KERNEL
# include <sys/dditypes.h>
# endif
# include <sys/stream.h>
# include <sys/kmem.h>
#endif
#include <net/if.h>
#ifdef sun
# include <net/af.h>
#endif
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#if !defined(linux)
# include <netinet/ip_var.h>
#endif
#if !defined(__hpux) && !defined(linux)
# include <netinet/tcp_fsm.h>
#endif
#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_nat.h"
#include "netinet/ip_frag.h"
#include "netinet/ip_state.h"
#include "netinet/ip_proxy.h"
#ifdef IPFILTER_SYNC
#include "netinet/ip_sync.h"
#endif
#ifdef IPFILTER_SCAN
#include "netinet/ip_scan.h"
#endif
#ifdef USE_INET6
#include <netinet/icmp6.h>
#endif
#if (__FreeBSD_version >= 300000)
# include <sys/malloc.h>
# if defined(_KERNEL) && !defined(IPFILTER_LKM)
# include <sys/libkern.h>
# include <sys/systm.h>
# endif
#endif
/* END OF INCLUDES */
#if !defined(lint)
#if defined(__NetBSD__)
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ip_state.c,v 1.7 2005/04/03 15:05:30 martti Exp $");
#else
static const char sccsid[] = "@(#)ip_state.c 1.8 6/5/96 (C) 1993-2000 Darren Reed";
static const char rcsid[] = "@(#)Id: ip_state.c,v 2.186.2.29 2005/03/28 10:47:54 darrenr Exp";
#endif
#endif
static ipstate_t **ips_table = NULL;
static u_long *ips_seed = NULL;
static int ips_num = 0;
static u_long ips_last_force_flush = 0;
ips_stat_t ips_stats;
#ifdef USE_INET6
static ipstate_t *fr_checkicmp6matchingstate __P((fr_info_t *));
#endif
static ipstate_t *fr_matchsrcdst __P((fr_info_t *, ipstate_t *, i6addr_t *,
i6addr_t *, tcphdr_t *, u_32_t));
static ipstate_t *fr_checkicmpmatchingstate __P((fr_info_t *));
static int fr_state_flush __P((int, int));
static ips_stat_t *fr_statetstats __P((void));
static void fr_delstate __P((ipstate_t *, int));
static int fr_state_remove __P((caddr_t));
static void fr_ipsmove __P((ipstate_t *, u_int));
static int fr_tcpstate __P((fr_info_t *, tcphdr_t *, ipstate_t *));
static int fr_tcpoptions __P((fr_info_t *, tcphdr_t *, tcpdata_t *));
static ipstate_t *fr_stclone __P((fr_info_t *, tcphdr_t *, ipstate_t *));
static void fr_fixinisn __P((fr_info_t *, ipstate_t *));
static void fr_fixoutisn __P((fr_info_t *, ipstate_t *));
static void fr_checknewisn __P((fr_info_t *, ipstate_t *));
int fr_stputent __P((caddr_t));
int fr_stgetent __P((caddr_t));
#define ONE_DAY IPF_TTLVAL(1 * 86400) /* 1 day */
#define FIVE_DAYS (5 * ONE_DAY)
#define DOUBLE_HASH(x) (((x) + ips_seed[(x) % fr_statesize]) % fr_statesize)
u_long fr_tcpidletimeout = FIVE_DAYS,
fr_tcpclosewait = IPF_TTLVAL(2 * TCP_MSL),
fr_tcplastack = IPF_TTLVAL(2 * TCP_MSL),
fr_tcptimeout = IPF_TTLVAL(2 * TCP_MSL),
fr_tcpclosed = IPF_TTLVAL(60),
fr_tcphalfclosed = IPF_TTLVAL(2 * 3600), /* 2 hours */
fr_udptimeout = IPF_TTLVAL(120),
fr_udpacktimeout = IPF_TTLVAL(12),
fr_icmptimeout = IPF_TTLVAL(60),
fr_icmpacktimeout = IPF_TTLVAL(6),
fr_iptimeout = IPF_TTLVAL(60);
int fr_statemax = IPSTATE_MAX,
fr_statesize = IPSTATE_SIZE;
int fr_state_doflush = 0,
fr_state_lock = 0,
fr_state_maxbucket = 0,
fr_state_maxbucket_reset = 1,
fr_state_init = 0;
ipftq_t ips_tqtqb[IPF_TCP_NSTATES],
ips_udptq,
ips_udpacktq,
ips_iptq,
ips_icmptq,
ips_icmpacktq,
*ips_utqe = NULL;
#ifdef IPFILTER_LOG
int ipstate_logging = 1;
#else
int ipstate_logging = 0;
#endif
ipstate_t *ips_list = NULL;
/* ------------------------------------------------------------------------ */
/* Function: fr_stateinit */
/* Returns: int - 0 == success, -1 == failure */
/* Parameters: Nil */
/* */
/* Initialise all the global variables used within the state code. */
/* This action also includes initiailising locks. */
/* ------------------------------------------------------------------------ */
int fr_stateinit()
{
int i;
KMALLOCS(ips_table, ipstate_t **, fr_statesize * sizeof(ipstate_t *));
if (ips_table == NULL)
return -1;
bzero((char *)ips_table, fr_statesize * sizeof(ipstate_t *));
KMALLOCS(ips_seed, u_long *, fr_statesize * sizeof(*ips_seed));
if (ips_seed == NULL)
return -2;
for (i = 0; i < fr_statesize; i++) {
/*
* XXX - ips_seed[X] should be a random number of sorts.
*/
#if (__FreeBSD_version >= 400000)
ips_seed[i] = arc4random();
#else
ips_seed[i] = ((u_long)ips_seed + i) * fr_statesize;
ips_seed[i] ^= 0xa5a55a5a;
ips_seed[i] *= (u_long)ips_seed;
ips_seed[i] ^= 0x5a5aa5a5;
ips_seed[i] *= fr_statemax;
#endif
}
/* fill icmp reply type table */
for (i = 0; i <= ICMP_MAXTYPE; i++)
icmpreplytype4[i] = -1;
icmpreplytype4[ICMP_ECHO] = ICMP_ECHOREPLY;
icmpreplytype4[ICMP_TSTAMP] = ICMP_TSTAMPREPLY;
icmpreplytype4[ICMP_IREQ] = ICMP_IREQREPLY;
icmpreplytype4[ICMP_MASKREQ] = ICMP_MASKREPLY;
#ifdef USE_INET6
/* fill icmp reply type table */
for (i = 0; i <= ICMP6_MAXTYPE; i++)
icmpreplytype6[i] = -1;
icmpreplytype6[ICMP6_ECHO_REQUEST] = ICMP6_ECHO_REPLY;
icmpreplytype6[ICMP6_MEMBERSHIP_QUERY] = ICMP6_MEMBERSHIP_REPORT;
icmpreplytype6[ICMP6_NI_QUERY] = ICMP6_NI_REPLY;
icmpreplytype6[ND_ROUTER_SOLICIT] = ND_ROUTER_ADVERT;
icmpreplytype6[ND_NEIGHBOR_SOLICIT] = ND_NEIGHBOR_ADVERT;
#endif
KMALLOCS(ips_stats.iss_bucketlen, u_long *,
fr_statesize * sizeof(u_long));
if (ips_stats.iss_bucketlen == NULL)
return -1;
bzero((char *)ips_stats.iss_bucketlen, fr_statesize * sizeof(u_long));
if (fr_state_maxbucket == 0) {
for (i = fr_statesize; i > 0; i >>= 1)
fr_state_maxbucket++;
fr_state_maxbucket *= 2;
}
fr_sttab_init(ips_tqtqb);
ips_tqtqb[IPF_TCP_NSTATES - 1].ifq_next = &ips_udptq;
ips_udptq.ifq_ttl = (u_long)fr_udptimeout;
ips_udptq.ifq_ref = 1;
ips_udptq.ifq_head = NULL;
ips_udptq.ifq_tail = &ips_udptq.ifq_head;
MUTEX_INIT(&ips_udptq.ifq_lock, "ipftq udp tab");
ips_udptq.ifq_next = &ips_udpacktq;
ips_udpacktq.ifq_ttl = (u_long)fr_udpacktimeout;
ips_udpacktq.ifq_ref = 1;
ips_udpacktq.ifq_head = NULL;
ips_udpacktq.ifq_tail = &ips_udpacktq.ifq_head;
MUTEX_INIT(&ips_udpacktq.ifq_lock, "ipftq udpack tab");
ips_udpacktq.ifq_next = &ips_icmptq;
ips_icmptq.ifq_ttl = (u_long)fr_icmptimeout;
ips_icmptq.ifq_ref = 1;
ips_icmptq.ifq_head = NULL;
ips_icmptq.ifq_tail = &ips_icmptq.ifq_head;
MUTEX_INIT(&ips_icmptq.ifq_lock, "ipftq icmp tab");
ips_icmptq.ifq_next = &ips_icmpacktq;
ips_icmpacktq.ifq_ttl = (u_long)fr_icmpacktimeout;
ips_icmpacktq.ifq_ref = 1;
ips_icmpacktq.ifq_head = NULL;
ips_icmpacktq.ifq_tail = &ips_icmpacktq.ifq_head;
MUTEX_INIT(&ips_icmpacktq.ifq_lock, "ipftq icmpack tab");
ips_icmpacktq.ifq_next = &ips_iptq;
ips_iptq.ifq_ttl = (u_long)fr_iptimeout;
ips_iptq.ifq_ref = 1;
ips_iptq.ifq_head = NULL;
ips_iptq.ifq_tail = &ips_iptq.ifq_head;
MUTEX_INIT(&ips_iptq.ifq_lock, "ipftq ip tab");
ips_iptq.ifq_next = NULL;
RWLOCK_INIT(&ipf_state, "ipf IP state rwlock");
MUTEX_INIT(&ipf_stinsert, "ipf state insert mutex");
fr_state_init = 1;
ips_last_force_flush = fr_ticks;
return 0;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_stateunload */
/* Returns: Nil */
/* Parameters: Nil */
/* */
/* Release and destroy any resources acquired or initialised so that */
/* IPFilter can be unloaded or re-initialised. */
/* ------------------------------------------------------------------------ */
void fr_stateunload()
{
ipftq_t *ifq, *ifqnext;
ipstate_t *is;
while ((is = ips_list) != NULL)
fr_delstate(is, 0);
/*
* Proxy timeout queues are not cleaned here because although they
* exist on the state list, appr_unload is called after fr_stateunload
* and the proxies actually are responsible for them being created.
* Should the proxy timeouts have their own list? There's no real
* justification as this is the only complicationA
*/
for (ifq = ips_utqe; ifq != NULL; ifq = ifqnext) {
ifqnext = ifq->ifq_next;
if (((ifq->ifq_flags & IFQF_PROXY) == 0) &&
(fr_deletetimeoutqueue(ifq) == 0))
fr_freetimeoutqueue(ifq);
}
ips_stats.iss_inuse = 0;
ips_num = 0;
if (fr_state_init == 1) {
fr_sttab_destroy(ips_tqtqb);
MUTEX_DESTROY(&ips_udptq.ifq_lock);
MUTEX_DESTROY(&ips_icmptq.ifq_lock);
MUTEX_DESTROY(&ips_udpacktq.ifq_lock);
MUTEX_DESTROY(&ips_icmpacktq.ifq_lock);
MUTEX_DESTROY(&ips_iptq.ifq_lock);
}
if (ips_table != NULL) {
KFREES(ips_table, fr_statesize * sizeof(*ips_table));
ips_table = NULL;
}
if (ips_seed != NULL) {
KFREES(ips_seed, fr_statesize * sizeof(*ips_seed));
ips_seed = NULL;
}
if (ips_stats.iss_bucketlen != NULL) {
KFREES(ips_stats.iss_bucketlen, fr_statesize * sizeof(u_long));
ips_stats.iss_bucketlen = NULL;
}
if (fr_state_maxbucket_reset == 1)
fr_state_maxbucket = 0;
if (fr_state_init == 1) {
fr_state_init = 0;
RW_DESTROY(&ipf_state);
MUTEX_DESTROY(&ipf_stinsert);
}
}
/* ------------------------------------------------------------------------ */
/* Function: fr_statetstats */
/* Returns: ips_state_t* - pointer to state stats structure */
/* Parameters: Nil */
/* */
/* Put all the current numbers and pointers into a single struct and return */
/* a pointer to it. */
/* ------------------------------------------------------------------------ */
static ips_stat_t *fr_statetstats()
{
ips_stats.iss_active = ips_num;
ips_stats.iss_statesize = fr_statesize;
ips_stats.iss_statemax = fr_statemax;
ips_stats.iss_table = ips_table;
ips_stats.iss_list = ips_list;
ips_stats.iss_ticks = fr_ticks;
return &ips_stats;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_state_remove */
/* Returns: int - 0 == success, != 0 == failure */
/* Parameters: data(I) - pointer to state structure to delete from table */
/* */
/* Search for a state structure that matches the one passed, according to */
/* the IP addresses and other protocol specific information. */
/* ------------------------------------------------------------------------ */
static int fr_state_remove(data)
caddr_t data;
{
ipstate_t *sp, st;
int error;
sp = &st;
error = fr_inobj(data, &st, IPFOBJ_IPSTATE);
if (error)
return EFAULT;
WRITE_ENTER(&ipf_state);
for (sp = ips_list; sp; sp = sp->is_next)
if ((sp->is_p == st.is_p) && (sp->is_v == st.is_v) &&
!bcmp((caddr_t)&sp->is_src, (caddr_t)&st.is_src,
sizeof(st.is_src)) &&
!bcmp((caddr_t)&sp->is_dst, (caddr_t)&st.is_src,
sizeof(st.is_dst)) &&
!bcmp((caddr_t)&sp->is_ps, (caddr_t)&st.is_ps,
sizeof(st.is_ps))) {
fr_delstate(sp, ISL_REMOVE);
RWLOCK_EXIT(&ipf_state);
return 0;
}
RWLOCK_EXIT(&ipf_state);
return ESRCH;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_state_ioctl */
/* Returns: int - 0 == success, != 0 == failure */
/* Parameters: data(I) - pointer to ioctl data */
/* cmd(I) - ioctl command integer */
/* mode(I) - file mode bits used with open */
/* */
/* Processes an ioctl call made to operate on the IP Filter state device. */
/* ------------------------------------------------------------------------ */
int fr_state_ioctl(data, cmd, mode)
caddr_t data;
ioctlcmd_t cmd;
int mode;
{
int arg, ret, error = 0;
switch (cmd)
{
/*
* Delete an entry from the state table.
*/
case SIOCDELST :
error = fr_state_remove(data);
break;
/*
* Flush the state table
*/
case SIOCIPFFL :
BCOPYIN(data, (char *)&arg, sizeof(arg));
if (arg == 0 || arg == 1) {
WRITE_ENTER(&ipf_state);
ret = fr_state_flush(arg, 4);
RWLOCK_EXIT(&ipf_state);
BCOPYOUT((char *)&ret, data, sizeof(ret));
} else
error = EINVAL;
break;
#ifdef USE_INET6
case SIOCIPFL6 :
BCOPYIN(data, (char *)&arg, sizeof(arg));
if (arg == 0 || arg == 1) {
WRITE_ENTER(&ipf_state);
ret = fr_state_flush(arg, 6);
RWLOCK_EXIT(&ipf_state);
BCOPYOUT((char *)&ret, data, sizeof(ret));
} else
error = EINVAL;
break;
#endif
#ifdef IPFILTER_LOG
/*
* Flush the state log.
*/
case SIOCIPFFB :
if (!(mode & FWRITE))
error = EPERM;
else {
int tmp;
tmp = ipflog_clear(IPL_LOGSTATE);
BCOPYOUT((char *)&tmp, data, sizeof(tmp));
}
break;
/*
* Turn logging of state information on/off.
*/
case SIOCSETLG :
if (!(mode & FWRITE))
error = EPERM;
else {
BCOPYIN((char *)data, (char *)&ipstate_logging,
sizeof(ipstate_logging));
}
break;
/*
* Return the current state of logging.
*/
case SIOCGETLG :
BCOPYOUT((char *)&ipstate_logging, (char *)data,
sizeof(ipstate_logging));
break;
/*
* Return the number of bytes currently waiting to be read.
*/
case FIONREAD :
arg = iplused[IPL_LOGSTATE]; /* returned in an int */
BCOPYOUT((char *)&arg, data, sizeof(arg));
break;
#endif
/*
* Get the current state statistics.
*/
case SIOCGETFS :
error = fr_outobj(data, fr_statetstats(), IPFOBJ_STATESTAT);
break;
/*
* Lock/Unlock the state table. (Locking prevents any changes, which
* means no packets match).
*/
case SIOCSTLCK :
fr_lock(data, &fr_state_lock);
break;
/*
* Add an entry to the current state table.
*/
case SIOCSTPUT :
if (!fr_state_lock) {
error = EACCES;
break;
}
error = fr_stputent(data);
break;
/*
* Get a state table entry.
*/
case SIOCSTGET :
if (!fr_state_lock) {
error = EACCES;
break;
}
error = fr_stgetent(data);
break;
default :
error = EINVAL;
break;
}
return error;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_stgetent */
/* Returns: int - 0 == success, != 0 == failure */
/* Parameters: data(I) - pointer to state structure to retrieve from table */
/* */
/* Copy out state information from the kernel to a user space process. If */
/* there is a filter rule associated with the state entry, copy that out */
/* as well. The entry to copy out is taken from the value of "ips_next" in */
/* the struct passed in and if not null and not found in the list of current*/
/* state entries, the retrieval fails. */
/* ------------------------------------------------------------------------ */
int fr_stgetent(data)
caddr_t data;
{
ipstate_t *is, *isn;
ipstate_save_t ips;
int error;
error = fr_inobj(data, &ips, IPFOBJ_STATESAVE);
if (error)
return EFAULT;
isn = ips.ips_next;
if (isn == NULL) {
isn = ips_list;
if (isn == NULL) {
if (ips.ips_next == NULL)
return ENOENT;
return 0;
}
} else {
/*
* Make sure the pointer we're copying from exists in the
* current list of entries. Security precaution to prevent
* copying of random kernel data.
*/
for (is = ips_list; is; is = is->is_next)
if (is == isn)
break;
if (!is)
return ESRCH;
}
ips.ips_next = isn->is_next;
bcopy((char *)isn, (char *)&ips.ips_is, sizeof(ips.ips_is));
ips.ips_rule = isn->is_rule;
if (isn->is_rule != NULL)
bcopy((char *)isn->is_rule, (char *)&ips.ips_fr,
sizeof(ips.ips_fr));
error = fr_outobj(data, &ips, IPFOBJ_STATESAVE);
if (error)
return EFAULT;
return 0;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_stputent */
/* Returns: int - 0 == success, != 0 == failure */
/* Parameters: data(I) - pointer to state information struct */
/* */
/* This function implements the SIOCSTPUT ioctl: insert a state entry into */
/* the state table. If the state info. includes a pointer to a filter rule */
/* then also add in an orphaned rule (will not show up in any "ipfstat -io" */
/* output. */
/* ------------------------------------------------------------------------ */
int fr_stputent(data)
caddr_t data;
{
ipstate_t *is, *isn;
ipstate_save_t ips;
int error, out, i;
frentry_t *fr;
char *name;
error = fr_inobj(data, &ips, IPFOBJ_STATESAVE);
if (error)
return EFAULT;
KMALLOC(isn, ipstate_t *);
if (isn == NULL)
return ENOMEM;
bcopy((char *)&ips.ips_is, (char *)isn, sizeof(*isn));
bzero((char *)isn, offsetof(struct ipstate, is_pkts));
isn->is_sti.tqe_pnext = NULL;
isn->is_sti.tqe_next = NULL;
isn->is_sti.tqe_ifq = NULL;
isn->is_sti.tqe_parent = isn;
isn->is_ifp[0] = NULL;
isn->is_ifp[1] = NULL;
isn->is_ifp[2] = NULL;
isn->is_ifp[3] = NULL;
isn->is_sync = NULL;
fr = ips.ips_rule;
if (fr == NULL) {
READ_ENTER(&ipf_state);
fr_stinsert(isn, 0);
RWLOCK_EXIT(&ipf_state);
return 0;
}
if (isn->is_flags & SI_NEWFR) {
KMALLOC(fr, frentry_t *);
if (fr == NULL) {
KFREE(isn);
return ENOMEM;
}
bcopy((char *)&ips.ips_fr, (char *)fr, sizeof(*fr));
out = fr->fr_flags & FR_OUTQUE ? 1 : 0;
isn->is_rule = fr;
ips.ips_is.is_rule = fr;
MUTEX_NUKE(&fr->fr_lock);
MUTEX_INIT(&fr->fr_lock, "state filter rule lock");
/*
* Look up all the interface names in the rule.
*/
for (i = 0; i < 4; i++) {
name = fr->fr_ifnames[i];
fr->fr_ifas[i] = fr_resolvenic(name, fr->fr_v);
name = isn->is_ifname[i];
isn->is_ifp[i] = fr_resolvenic(name, isn->is_v);
}
fr->fr_ref = 0;
fr->fr_dsize = 0;
fr->fr_data = NULL;
fr_resolvedest(&fr->fr_tif, fr->fr_v);
fr_resolvedest(&fr->fr_dif, fr->fr_v);
/*
* send a copy back to userland of what we ended up
* to allow for verification.
*/
error = fr_outobj(data, &ips, IPFOBJ_STATESAVE);
if (error) {
KFREE(isn);
MUTEX_DESTROY(&fr->fr_lock);
KFREE(fr);
return EFAULT;
}
READ_ENTER(&ipf_state);
fr_stinsert(isn, 0);
RWLOCK_EXIT(&ipf_state);
} else {
READ_ENTER(&ipf_state);
for (is = ips_list; is; is = is->is_next)
if (is->is_rule == fr) {
fr_stinsert(isn, 0);
break;
}
if (is == NULL) {
KFREE(isn);
isn = NULL;
}
RWLOCK_EXIT(&ipf_state);
return (isn == NULL) ? ESRCH : 0;
}
return 0;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_stinsert */
/* Returns: Nil */
/* Parameters: is(I) - pointer to state structure */
/* rev(I) - flag indicating forward/reverse direction of packet */
/* */
/* Inserts a state structure into the hash table (for lookups) and the list */
/* of state entries (for enumeration). Resolves all of the interface names */
/* to pointers and adjusts running stats for the hash table as appropriate. */
/* */
/* Locking: it is assumed that some kind of lock on ipf_state is held. */
/* ------------------------------------------------------------------------ */
void fr_stinsert(is, rev)
ipstate_t *is;
int rev;
{
frentry_t *fr;
u_int hv;
int i;
MUTEX_INIT(&is->is_lock, "ipf state entry");
fr = is->is_rule;
if (fr != NULL) {
MUTEX_ENTER(&fr->fr_lock);
fr->fr_ref++;
fr->fr_statecnt++;
MUTEX_EXIT(&fr->fr_lock);
}
/*
* Look up all the interface names in the state entry.
*/
for (i = 0; i < 4; i++) {
if (is->is_ifp[i] != NULL)
continue;
is->is_ifp[i] = fr_resolvenic(is->is_ifname[i], is->is_v);
}
/*
* If we could trust is_hv, then the modulous would not be needed, but
* when running with IPFILTER_SYNC, this stops bad values.
*/
hv = is->is_hv % fr_statesize;
is->is_hv = hv;
/*
* We need to get both of these locks...the first because it is
* possible that once the insert is complete another packet might
* come along, match the entry and want to update it.
*/
MUTEX_ENTER(&is->is_lock);
MUTEX_ENTER(&ipf_stinsert);
/*
* add into list table.
*/
if (ips_list != NULL)
ips_list->is_pnext = &is->is_next;
is->is_pnext = &ips_list;
is->is_next = ips_list;
ips_list = is;
if (ips_table[hv] != NULL)
ips_table[hv]->is_phnext = &is->is_hnext;
else
ips_stats.iss_inuse++;
is->is_phnext = ips_table + hv;
is->is_hnext = ips_table[hv];
ips_table[hv] = is;
ips_stats.iss_bucketlen[hv]++;
ips_num++;
MUTEX_EXIT(&ipf_stinsert);
fr_setstatequeue(is, rev);
MUTEX_EXIT(&is->is_lock);
}
/* ------------------------------------------------------------------------ */
/* Function: fr_addstate */
/* Returns: ipstate_t* - NULL == failure, else pointer to new state */
/* Parameters: fin(I) - pointer to packet information */
/* stsave(O) - pointer to place to save pointer to created */
/* state structure. */
/* flags(I) - flags to use when creating the structure */
/* */
/* Creates a new IP state structure from the packet information collected. */
/* Inserts it into the state table and appends to the bottom of the active */
/* list. If the capacity of the table has reached the maximum allowed then */
/* the call will fail and a flush is scheduled for the next timeout call. */
/* ------------------------------------------------------------------------ */
ipstate_t *fr_addstate(fin, stsave, flags)
fr_info_t *fin;
ipstate_t **stsave;
u_int flags;
{
ipstate_t *is, ips;
struct icmp *ic;
u_int pass, hv;
frentry_t *fr;
tcphdr_t *tcp;
grehdr_t *gre;
void *ifp;
int out;
if (fr_state_lock ||
(fin->fin_flx & (FI_SHORT|FI_STATE|FI_FRAGBODY|FI_BAD)))
return NULL;
if ((fin->fin_flx & FI_OOW) && !(fin->fin_tcpf & TH_SYN))
return NULL;
fr = fin->fin_fr;
if ((fr->fr_statemax == 0) && (ips_num == fr_statemax)) {
ATOMIC_INCL(ips_stats.iss_max);
fr_state_doflush = 1;
return NULL;
}
/*
* If a "keep state" rule has reached the maximum number of references
* to it, then schedule an automatic flush in case we can clear out
* some "dead old wood".
*/
if ((fr != NULL) && (fr->fr_statemax != 0) &&
(fr->fr_statecnt >= fr->fr_statemax)) {
MUTEX_EXIT(&fr->fr_lock);
ATOMIC_INCL(ips_stats.iss_maxref);
fr_state_doflush = 1;
return NULL;
}
pass = (fr == NULL) ? 0 : fr->fr_flags;
ic = NULL;
tcp = NULL;
out = fin->fin_out;
is = &ips;
bzero((char *)is, sizeof(*is));
is->is_die = 1 + fr_ticks;
/*
* Copy and calculate...
*/
hv = (is->is_p = fin->fin_fi.fi_p);
is->is_src = fin->fin_fi.fi_src;
hv += is->is_saddr;
is->is_dst = fin->fin_fi.fi_dst;
hv += is->is_daddr;
#ifdef USE_INET6
if (fin->fin_v == 6) {
/*
* For ICMPv6, we check to see if the destination address is
* a multicast address. If it is, do not include it in the
* calculation of the hash because the correct reply will come
* back from a real address, not a multicast address.
*/
if ((is->is_p == IPPROTO_ICMPV6) &&
IN6_IS_ADDR_MULTICAST(&is->is_dst.in6)) {
/*
* So you can do keep state with neighbour discovery.
*
* Here we could use the address from the neighbour
* solicit message to put in the state structure and
* we could use that without a wildcard flag too...
*/
flags |= SI_W_DADDR;
hv -= is->is_daddr;
} else {
hv += is->is_dst.i6[1];
hv += is->is_dst.i6[2];
hv += is->is_dst.i6[3];
}
hv += is->is_src.i6[1];
hv += is->is_src.i6[2];
hv += is->is_src.i6[3];
}
#endif
switch (is->is_p)
{
#ifdef USE_INET6
case IPPROTO_ICMPV6 :
ic = fin->fin_dp;
switch (ic->icmp_type)
{
case ICMP6_ECHO_REQUEST :
is->is_icmp.ici_type = ic->icmp_type;
hv += (is->is_icmp.ici_id = ic->icmp_id);
break;
case ICMP6_MEMBERSHIP_QUERY :
case ND_ROUTER_SOLICIT :
case ND_NEIGHBOR_SOLICIT :
case ICMP6_NI_QUERY :
is->is_icmp.ici_type = ic->icmp_type;
break;
default :
return NULL;
}
ATOMIC_INCL(ips_stats.iss_icmp);
break;
#endif
case IPPROTO_ICMP :
ic = fin->fin_dp;
switch (ic->icmp_type)
{
case ICMP_ECHO :
case ICMP_TSTAMP :
case ICMP_IREQ :
case ICMP_MASKREQ :
is->is_icmp.ici_type = ic->icmp_type;
hv += (is->is_icmp.ici_id = ic->icmp_id);
break;
default :
return NULL;
}
ATOMIC_INCL(ips_stats.iss_icmp);
break;
case IPPROTO_GRE :
gre = fin->fin_dp;
is->is_gre.gs_flags = gre->gr_flags;
is->is_gre.gs_ptype = gre->gr_ptype;
if (GRE_REV(is->is_gre.gs_flags) == 1) {
is->is_call[0] = fin->fin_data[0];
is->is_call[1] = fin->fin_data[1];
}
break;
case IPPROTO_TCP :
tcp = fin->fin_dp;
if (tcp->th_flags & TH_RST)
return NULL;
/*
* The endian of the ports doesn't matter, but the ack and
* sequence numbers do as we do mathematics on them later.
*/
is->is_sport = htons(fin->fin_data[0]);
is->is_dport = htons(fin->fin_data[1]);
if ((flags & (SI_W_DPORT|SI_W_SPORT)) == 0) {
hv += is->is_sport;
hv += is->is_dport;
}
/*
* If this is a real packet then initialise fields in the
* state information structure from the TCP header information.
*/
is->is_maxdwin = 1;
is->is_maxswin = ntohs(tcp->th_win);
if (is->is_maxswin == 0)
is->is_maxswin = 1;
if ((fin->fin_flx & FI_IGNORE) == 0) {
is->is_send = ntohl(tcp->th_seq) + fin->fin_dlen -
(TCP_OFF(tcp) << 2) +
((tcp->th_flags & TH_SYN) ? 1 : 0) +
((tcp->th_flags & TH_FIN) ? 1 : 0);
is->is_maxsend = is->is_send;
/*
* Window scale option is only present in
* SYN/SYN-ACK packet.
*/
if ((tcp->th_flags & ~(TH_FIN|TH_ACK|TH_ECNALL)) ==
TH_SYN &&
(TCP_OFF(tcp) > (sizeof(tcphdr_t) >> 2))) {
if (fr_tcpoptions(fin, tcp,
&is->is_tcp.ts_data[0]))
is->is_swinflags = TCP_WSCALE_SEEN|
TCP_WSCALE_FIRST;
}
if ((fin->fin_out != 0) && (pass & FR_NEWISN) != 0) {
fr_checknewisn(fin, is);
fr_fixoutisn(fin, is);
}
if ((tcp->th_flags & TH_OPENING) == TH_SYN)
flags |= IS_TCPFSM;
else {
is->is_maxdwin = is->is_maxswin * 2;
is->is_dend = ntohl(tcp->th_ack);
is->is_maxdend = ntohl(tcp->th_ack);
is->is_maxdwin *= 2;
}
}
/*
* If we're creating state for a starting connection, start the
* timer on it as we'll never see an error if it fails to
* connect.
*/
ATOMIC_INCL(ips_stats.iss_tcp);
break;
case IPPROTO_UDP :
tcp = fin->fin_dp;
is->is_sport = htons(fin->fin_data[0]);
is->is_dport = htons(fin->fin_data[1]);
if ((flags & (SI_W_DPORT|SI_W_SPORT)) == 0) {
hv += tcp->th_dport;
hv += tcp->th_sport;
}
ATOMIC_INCL(ips_stats.iss_udp);
break;
default :
break;
}
hv = DOUBLE_HASH(hv);
is->is_hv = hv;
is->is_rule = fr;
is->is_flags = flags & IS_INHERITED;
/*
* Look for identical state.
*/
for (is = ips_table[is->is_hv % fr_statesize]; is != NULL;
is = is->is_hnext) {
if (bcmp(&ips.is_src, &is->is_src,
offsetof(struct ipstate, is_ps) -
offsetof(struct ipstate, is_src)) == 0)
break;
}
if (is != NULL)
return NULL;
if (ips_stats.iss_bucketlen[hv] >= fr_state_maxbucket) {
ATOMIC_INCL(ips_stats.iss_bucketfull);
return NULL;
}
KMALLOC(is, ipstate_t *);
if (is == NULL) {
ATOMIC_INCL(ips_stats.iss_nomem);
return NULL;
}
bcopy((char *)&ips, (char *)is, sizeof(*is));
/*
* Do not do the modulous here, it is done in fr_stinsert().
*/
if (fr != NULL) {
(void) strncpy(is->is_group, fr->fr_group, FR_GROUPLEN);
if (fr->fr_age[0] != 0) {
is->is_tqehead[0] = fr_addtimeoutqueue(&ips_utqe,
fr->fr_age[0]);
is->is_sti.tqe_flags |= TQE_RULEBASED;
}
if (fr->fr_age[1] != 0) {
is->is_tqehead[1] = fr_addtimeoutqueue(&ips_utqe,
fr->fr_age[1]);
is->is_sti.tqe_flags |= TQE_RULEBASED;
}
is->is_tag = fr->fr_logtag;
is->is_ifp[(out << 1) + 1] = fr->fr_ifas[1];
is->is_ifp[(1 - out) << 1] = fr->fr_ifas[2];
is->is_ifp[((1 - out) << 1) + 1] = fr->fr_ifas[3];
if (((ifp = fr->fr_ifas[1]) != NULL) &&
(ifp != (void *)-1)) {
COPYIFNAME(ifp, is->is_ifname[(out << 1) + 1]);
}
if (((ifp = fr->fr_ifas[2]) != NULL) &&
(ifp != (void *)-1)) {
COPYIFNAME(ifp, is->is_ifname[(1 - out) << 1]);
}
if (((ifp = fr->fr_ifas[3]) != NULL) &&
(ifp != (void *)-1)) {
COPYIFNAME(ifp, is->is_ifname[((1 - out) << 1) + 1]);
}
} else {
pass = fr_flags;
is->is_tag = FR_NOLOGTAG;
}
is->is_ifp[out << 1] = fin->fin_ifp;
if (fin->fin_ifp != NULL) {
COPYIFNAME(fin->fin_ifp, is->is_ifname[out << 1]);
}
/*
* It may seem strange to set is_ref to 2, but fr_check() will call
* fr_statederef() after calling fr_addstate() and the idea is to
* have it exist at the end of fr_check() with is_ref == 1.
*/
is->is_ref = 2;
is->is_pass = pass;
is->is_pkts[0] = 0, is->is_bytes[0] = 0;
is->is_pkts[1] = 0, is->is_bytes[1] = 0;
is->is_pkts[2] = 0, is->is_bytes[2] = 0;
is->is_pkts[3] = 0, is->is_bytes[3] = 0;
if ((fin->fin_flx & FI_IGNORE) == 0) {
is->is_pkts[out] = 1;
is->is_bytes[out] = fin->fin_plen;
is->is_flx[out][0] = fin->fin_flx & FI_CMP;
is->is_flx[out][0] &= ~FI_OOW;
}
if (pass & FR_STSTRICT)
is->is_flags |= IS_STRICT;
if (pass & FR_STATESYNC)
is->is_flags |= IS_STATESYNC;
/*
* We want to check everything that is a property of this packet,
* but we don't (automatically) care about it's fragment status as
* this may change.
*/
is->is_v = fin->fin_v;
is->is_opt = fin->fin_optmsk;
is->is_optmsk = 0xffffffff;
is->is_sec = fin->fin_secmsk;
is->is_secmsk = 0xffff;
is->is_auth = fin->fin_auth;
is->is_authmsk = 0xffff;
if (flags & (SI_WILDP|SI_WILDA)) {
ATOMIC_INCL(ips_stats.iss_wild);
}
is->is_rulen = fin->fin_rule;
if (pass & FR_LOGFIRST)
is->is_pass &= ~(FR_LOGFIRST|FR_LOG);
READ_ENTER(&ipf_state);
is->is_me = stsave;
fr_stinsert(is, fin->fin_rev);
if (fin->fin_p == IPPROTO_TCP) {
/*
* If we're creating state for a starting connection, start the
* timer on it as we'll never see an error if it fails to
* connect.
*/
MUTEX_ENTER(&is->is_lock);
(void) fr_tcp_age(&is->is_sti, fin, ips_tqtqb, is->is_flags);
MUTEX_EXIT(&is->is_lock);
#ifdef IPFILTER_SCAN
if ((is->is_flags & SI_CLONE) == 0)
(void) ipsc_attachis(is);
#endif
}
#ifdef IPFILTER_SYNC
if ((is->is_flags & IS_STATESYNC) && ((is->is_flags & SI_CLONE) == 0))
is->is_sync = ipfsync_new(SMC_STATE, fin, is);
#endif
if (ipstate_logging)
ipstate_log(is, ISL_NEW);
RWLOCK_EXIT(&ipf_state);
fin->fin_state = is;
fin->fin_rev = IP6_NEQ(&is->is_dst, &fin->fin_daddr);
fin->fin_flx |= FI_STATE;
if (fin->fin_flx & FI_FRAG)
(void) fr_newfrag(fin, pass ^ FR_KEEPSTATE);
return is;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_tcpoptions */
/* Returns: int - 1 == packet matches state entry, 0 == it does not */
/* Parameters: fin(I) - pointer to packet information */
/* tcp(I) - pointer to TCP packet header */
/* td(I) - pointer to TCP data held as part of the state */
/* */
/* Look after the TCP header for any options and deal with those that are */
/* present. Record details about those that we recogise. */
/* ------------------------------------------------------------------------ */
static int fr_tcpoptions(fin, tcp, td)
fr_info_t *fin;
tcphdr_t *tcp;
tcpdata_t *td;
{
int off, mlen, ol, i, len, retval;
char buf[64], *s, opt;
mb_t *m = NULL;
off = fin->fin_hlen + sizeof(*tcp);
len = (TCP_OFF(tcp) << 2) - sizeof(*tcp);
if (fin->fin_plen < off + len)
return 0;
m = fin->fin_m;
off += fin->fin_ipoff;
mlen = MSGDSIZE(m) - off;
if (len > mlen) {
len = mlen;
retval = 0;
} else {
retval = 1;
}
COPYDATA(m, off, len, buf);
for (s = buf; len > 0; ) {
opt = *s;
if (opt == TCPOPT_EOL)
break;
else if (opt == TCPOPT_NOP)
ol = 1;
else {
if (len < 2)
break;
ol = (int)*(s + 1);
if (ol < 2 || ol > len)
break;
/*
* Extract the TCP options we are interested in out of
* the header and store them in the the tcpdata struct.
*/
switch (opt)
{
case TCPOPT_WINDOW :
if (ol == TCPOLEN_WINDOW) {
i = (int)*(s + 2);
if (i > TCP_WSCALE_MAX)
i = TCP_WSCALE_MAX;
else if (i < 0)
i = 0;
td->td_winscale = i;
}
break;
case TCPOPT_MAXSEG :
/*
* So, if we wanted to set the TCP MAXSEG,
* it should be done here...
*/
if (ol == TCPOLEN_MAXSEG) {
i = (int)*(s + 2);
i <<= 8;
i += (int)*(s + 3);
td->td_maxseg = i;
}
break;
}
}
len -= ol;
s += ol;
}
return retval;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_tcpstate */
/* Returns: int - 1 == packet matches state entry, 0 == it does not */
/* Parameters: fin(I) - pointer to packet information */
/* tcp(I) - pointer to TCP packet header */
/* is(I) - pointer to master state structure */
/* */
/* Check to see if a packet with TCP headers fits within the TCP window. */
/* Change timeout depending on whether new packet is a SYN-ACK returning */
/* for a SYN or a RST or FIN which indicate time to close up shop. */
/* ------------------------------------------------------------------------ */
static int fr_tcpstate(fin, tcp, is)
fr_info_t *fin;
tcphdr_t *tcp;
ipstate_t *is;
{
int source, ret = 0, flags;
tcpdata_t *fdata, *tdata;
source = !fin->fin_rev;
if (((is->is_flags & IS_TCPFSM) != 0) && (source == 1) &&
(ntohs(is->is_sport) != fin->fin_data[0]))
source = 0;
fdata = &is->is_tcp.ts_data[!source];
tdata = &is->is_tcp.ts_data[source];
MUTEX_ENTER(&is->is_lock);
if (fr_tcpinwindow(fin, fdata, tdata, tcp, is->is_flags)) {
#ifdef IPFILTER_SCAN
if (is->is_flags & (IS_SC_CLIENT|IS_SC_SERVER)) {
ipsc_packet(fin, is);
if (FR_ISBLOCK(is->is_pass)) {
MUTEX_EXIT(&is->is_lock);
return 1;
}
}
#endif
/*
* Nearing end of connection, start timeout.
*/
ret = fr_tcp_age(&is->is_sti, fin, ips_tqtqb, is->is_flags);
if (ret == 0) {
MUTEX_EXIT(&is->is_lock);
return 0;
}
/*
* set s0's as appropriate. Use syn-ack packet as it
* contains both pieces of required information.
*/
/*
* Window scale option is only present in SYN/SYN-ACK packet.
* Compare with ~TH_FIN to mask out T/TCP setups.
*/
flags = tcp->th_flags & ~(TH_FIN|TH_ECNALL);
if (flags == (TH_SYN|TH_ACK)) {
is->is_s0[source] = ntohl(tcp->th_ack);
is->is_s0[!source] = ntohl(tcp->th_seq) + 1;
if ((TCP_OFF(tcp) > (sizeof(tcphdr_t) >> 2)) &&
tdata->td_winscale) {
if (fr_tcpoptions(fin, tcp, fdata)) {
fdata->td_winflags = TCP_WSCALE_SEEN|
TCP_WSCALE_FIRST;
} else {
if (!fdata->td_winscale)
tdata->td_winscale = 0;
}
}
if ((fin->fin_out != 0) && (is->is_pass & FR_NEWISN))
fr_checknewisn(fin, is);
} else if (flags == TH_SYN) {
is->is_s0[source] = ntohl(tcp->th_seq) + 1;
if ((TCP_OFF(tcp) > (sizeof(tcphdr_t) >> 2)))
if (fr_tcpoptions(fin, tcp, tdata)) {
tdata->td_winflags = TCP_WSCALE_SEEN|
TCP_WSCALE_FIRST;
}
if ((fin->fin_out != 0) && (is->is_pass & FR_NEWISN))
fr_checknewisn(fin, is);
}
ret = 1;
} else
fin->fin_flx |= FI_OOW;
MUTEX_EXIT(&is->is_lock);
return ret;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_checknewisn */
/* Returns: Nil */
/* Parameters: fin(I) - pointer to packet information */
/* is(I) - pointer to master state structure */
/* */
/* Check to see if this TCP connection is expecting and needs a new */
/* sequence number for a particular direction of the connection. */
/* */
/* NOTE: This does not actually change the sequence numbers, only gets new */
/* one ready. */
/* ------------------------------------------------------------------------ */
static void fr_checknewisn(fin, is)
fr_info_t *fin;
ipstate_t *is;
{
u_32_t sumd, old, new;
tcphdr_t *tcp;
int i;
i = fin->fin_rev;
tcp = fin->fin_dp;
if (((i == 0) && !(is->is_flags & IS_ISNSYN)) ||
((i == 1) && !(is->is_flags & IS_ISNACK))) {
old = ntohl(tcp->th_seq);
new = fr_newisn(fin);
is->is_isninc[i] = new - old;
CALC_SUMD(old, new, sumd);
is->is_sumd[i] = (sumd & 0xffff) + (sumd >> 16);
is->is_flags |= ((i == 0) ? IS_ISNSYN : IS_ISNACK);
}
}
/* ------------------------------------------------------------------------ */
/* Function: fr_tcpinwindow */
/* Returns: int - 1 == packet inside TCP "window", 0 == not inside. */
/* Parameters: fin(I) - pointer to packet information */
/* fdata(I) - pointer to tcp state informatio (forward) */
/* tdata(I) - pointer to tcp state informatio (reverse) */
/* tcp(I) - pointer to TCP packet header */
/* */
/* Given a packet has matched addresses and ports, check to see if it is */
/* within the TCP data window. In a show of generosity, allow packets that */
/* are within the window space behind the current sequence # as well. */
/* ------------------------------------------------------------------------ */
int fr_tcpinwindow(fin, fdata, tdata, tcp, flags)
fr_info_t *fin;
tcpdata_t *fdata, *tdata;
tcphdr_t *tcp;
int flags;
{
#ifdef BROKEN_TCP_WINDOW_CHECK
tcp_seq seq, ack, end;
int ackskew, tcpflags;
u_32_t win, maxwin;
/*
* Find difference between last checked packet and this packet.
*/
tcpflags = tcp->th_flags;
seq = ntohl(tcp->th_seq);
ack = ntohl(tcp->th_ack);
if (tcpflags & TH_SYN)
win = ntohs(tcp->th_win);
else
win = ntohs(tcp->th_win) << fdata->td_winscale;
if (win == 0)
win = 1;
/*
* if window scaling is present, the scaling is only allowed
* for windows not in the first SYN packet. In that packet the
* window is 65535 to specify the largest window possible
* for receivers not implementing the window scale option.
* Currently, we do not assume TTCP here. That means that
* if we see a second packet from a host (after the initial
* SYN), we can assume that the receiver of the SYN did
* already send back the SYN/ACK (and thus that we know if
* the receiver also does window scaling)
*/
if (!(tcpflags & TH_SYN) && (fdata->td_winflags & TCP_WSCALE_FIRST)) {
if (tdata->td_winflags & TCP_WSCALE_SEEN) {
fdata->td_winflags &= ~TCP_WSCALE_FIRST;
fdata->td_maxwin = win;
} else {
fdata->td_winscale = 0;
fdata->td_winflags = 0;
tdata->td_winscale = 0;
tdata->td_winflags = 0;
}
}
end = seq + fin->fin_dlen - (TCP_OFF(tcp) << 2) +
((tcpflags & TH_SYN) ? 1 : 0) + ((tcpflags & TH_FIN) ? 1 : 0);
if ((fdata->td_end == 0) &&
(!(flags & IS_TCPFSM) ||
((tcpflags & TH_OPENING) == TH_OPENING))) {
/*
* Must be a (outgoing) SYN-ACK in reply to a SYN.
*/
fdata->td_end = end;
fdata->td_maxwin = 1;
fdata->td_maxend = end + win;
}
if (!(tcpflags & TH_ACK)) { /* Pretend an ack was sent */
ack = tdata->td_end;
} else if (((tcpflags & (TH_ACK|TH_RST)) == (TH_ACK|TH_RST)) &&
(ack == 0)) {
/* gross hack to get around certain broken tcp stacks */
ack = tdata->td_end;
}
if (seq == end)
seq = end = fdata->td_end;
maxwin = tdata->td_maxwin;
ackskew = tdata->td_end - ack;
/*
* Strict sequencing only allows in-order delivery.
*/
if ((flags & IS_STRICT) != 0) {
if (seq != fdata->td_end) {
return 0;
}
}
#define SEQ_GE(a,b) ((int)((a) - (b)) >= 0)
#define SEQ_GT(a,b) ((int)((a) - (b)) > 0)
if (
#if defined(_KERNEL)
(SEQ_GE(fdata->td_maxend, end)) &&
(SEQ_GE(seq, fdata->td_end - maxwin)) &&
#endif
/* XXX what about big packets */
#define MAXACKWINDOW 66000
(-ackskew <= (MAXACKWINDOW << fdata->td_winscale)) &&
( ackskew <= (MAXACKWINDOW << fdata->td_winscale))) {
/* if ackskew < 0 then this should be due to fragmented
* packets. There is no way to know the length of the
* total packet in advance.
* We do know the total length from the fragment cache though.
* Note however that there might be more sessions with
* exactly the same source and destination parameters in the
* state cache (and source and destination is the only stuff
* that is saved in the fragment cache). Note further that
* some TCP connections in the state cache are hashed with
* sport and dport as well which makes it not worthwhile to
* look for them.
* Thus, when ackskew is negative but still seems to belong
* to this session, we bump up the destinations end value.
*/
if (ackskew < 0)
tdata->td_end = ack;
/* update max window seen */
if (fdata->td_maxwin < win)
fdata->td_maxwin = win;
if (SEQ_GT(end, fdata->td_end))
fdata->td_end = end;
if (SEQ_GE(ack + win, tdata->td_maxend))
tdata->td_maxend = ack + win;
return 1;
}
return 0;
#else
return 1;
#endif
}
/* ------------------------------------------------------------------------ */
/* Function: fr_stclone */
/* Returns: ipstate_t* - NULL == cloning failed, */
/* else pointer to new state structure */
/* Parameters: fin(I) - pointer to packet information */
/* tcp(I) - pointer to TCP/UDP header */
/* is(I) - pointer to master state structure */
/* */
/* Create a "duplcate" state table entry from the master. */
/* ------------------------------------------------------------------------ */
static ipstate_t *fr_stclone(fin, tcp, is)
fr_info_t *fin;
tcphdr_t *tcp;
ipstate_t *is;
{
ipstate_t *clone;
u_32_t send;
if (ips_num == fr_statemax) {
ATOMIC_INCL(ips_stats.iss_max);
fr_state_doflush = 1;
return NULL;
}
KMALLOC(clone, ipstate_t *);
if (clone == NULL)
return NULL;
bcopy((char *)is, (char *)clone, sizeof(*clone));
MUTEX_NUKE(&clone->is_lock);
clone->is_die = ONE_DAY + fr_ticks;
clone->is_state[0] = 0;
clone->is_state[1] = 0;
send = ntohl(tcp->th_seq) + fin->fin_dlen - (TCP_OFF(tcp) << 2) +
((tcp->th_flags & TH_SYN) ? 1 : 0) +
((tcp->th_flags & TH_FIN) ? 1 : 0);
if (fin->fin_rev == 1) {
clone->is_dend = send;
clone->is_maxdend = send;
clone->is_send = 0;
clone->is_maxswin = 1;
clone->is_maxdwin = ntohs(tcp->th_win);
if (clone->is_maxdwin == 0)
clone->is_maxdwin = 1;
} else {
clone->is_send = send;
clone->is_maxsend = send;
clone->is_dend = 0;
clone->is_maxdwin = 1;
clone->is_maxswin = ntohs(tcp->th_win);
if (clone->is_maxswin == 0)
clone->is_maxswin = 1;
}
clone->is_flags &= ~SI_CLONE;
clone->is_flags |= SI_CLONED;
fr_stinsert(clone, fin->fin_rev);
MUTEX_ENTER(&clone->is_lock);
clone->is_ref = 1;
if (clone->is_p == IPPROTO_TCP) {
(void) fr_tcp_age(&clone->is_sti, fin, ips_tqtqb,
clone->is_flags);
}
MUTEX_EXIT(&clone->is_lock);
#ifdef IPFILTER_SCAN
(void) ipsc_attachis(is);
#endif
#ifdef IPFILTER_SYNC
if (is->is_flags & IS_STATESYNC)
clone->is_sync = ipfsync_new(SMC_STATE, fin, clone);
#endif
return clone;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_matchsrcdst */
/* Returns: Nil */
/* Parameters: fin(I) - pointer to packet information */
/* is(I) - pointer to state structure */
/* src(I) - pointer to source address */
/* dst(I) - pointer to destination address */
/* tcp(I) - pointer to TCP/UDP header */
/* */
/* Match a state table entry against an IP packet. The logic below is that */
/* ret gets set to one if the match succeeds, else remains 0. If it is */
/* still 0 after the test. no match. */
/* ------------------------------------------------------------------------ */
static ipstate_t *fr_matchsrcdst(fin, is, src, dst, tcp, cmask)
fr_info_t *fin;
ipstate_t *is;
i6addr_t *src, *dst;
tcphdr_t *tcp;
u_32_t cmask;
{
int ret = 0, rev, out, flags, flx = 0, idx;
u_short sp, dp;
u_32_t cflx;
void *ifp;
rev = IP6_NEQ(&is->is_dst, dst);
ifp = fin->fin_ifp;
out = fin->fin_out;
flags = is->is_flags;
sp = 0;
dp = 0;
if (tcp != NULL) {
sp = htons(fin->fin_sport);
dp = ntohs(fin->fin_dport);
}
if (!rev) {
if (tcp != NULL) {
if (!(flags & SI_W_SPORT) && (sp != is->is_sport))
rev = 1;
else if (!(flags & SI_W_DPORT) && (dp != is->is_dport))
rev = 1;
}
}
idx = (out << 1) + rev;
/*
* If the interface for this 'direction' is set, make sure it matches.
* An interface name that is not set matches any, as does a name of *.
*/
if ((is->is_ifp[idx] == NULL &&
(*is->is_ifname[idx] == '\0' || *is->is_ifname[idx] == '*')) ||
is->is_ifp[idx] == ifp)
ret = 1;
if (ret == 0)
return NULL;
ret = 0;
/*
* Match addresses and ports.
*/
if (rev == 0) {
if ((IP6_EQ(&is->is_dst, dst) || (flags & SI_W_DADDR)) &&
(IP6_EQ(&is->is_src, src) || (flags & SI_W_SADDR))) {
if (tcp) {
if ((sp == is->is_sport || flags & SI_W_SPORT)&&
(dp == is->is_dport || flags & SI_W_DPORT))
ret = 1;
} else {
ret = 1;
}
}
} else {
if ((IP6_EQ(&is->is_dst, src) || (flags & SI_W_DADDR)) &&
(IP6_EQ(&is->is_src, dst) || (flags & SI_W_SADDR))) {
if (tcp) {
if ((dp == is->is_sport || flags & SI_W_SPORT)&&
(sp == is->is_dport || flags & SI_W_DPORT))
ret = 1;
} else {
ret = 1;
}
}
}
if (ret == 0)
return NULL;
/*
* Whether or not this should be here, is questionable, but the aim
* is to get this out of the main line.
*/
if (tcp == NULL)
flags = is->is_flags & ~(SI_WILDP|SI_NEWFR|SI_CLONE|SI_CLONED);
/*
* Only one of the source or destination address can be flaged as a
* wildcard. Fill in the missing address, if set.
* For IPv6, if the address being copied in is multicast, then
* don't reset the wild flag - multicast causes it to be set in the
* first place!
*/
if ((flags & (SI_W_SADDR|SI_W_DADDR))) {
fr_ip_t *fi = &fin->fin_fi;
if ((flags & SI_W_SADDR) != 0) {
if (rev == 0) {
#ifdef USE_INET6
if (is->is_v == 6 &&
IN6_IS_ADDR_MULTICAST(&fi->fi_src.in6))
/*EMPTY*/;
else
#endif
{
is->is_src = fi->fi_src;
is->is_flags &= ~SI_W_SADDR;
}
} else {
#ifdef USE_INET6
if (is->is_v == 6 &&
IN6_IS_ADDR_MULTICAST(&fi->fi_dst.in6))
/*EMPTY*/;
else
#endif
{
is->is_src = fi->fi_dst;
is->is_flags &= ~SI_W_SADDR;
}
}
} else if ((flags & SI_W_DADDR) != 0) {
if (rev == 0) {
#ifdef USE_INET6
if (is->is_v == 6 &&
IN6_IS_ADDR_MULTICAST(&fi->fi_dst.in6))
/*EMPTY*/;
else
#endif
{
is->is_dst = fi->fi_dst;
is->is_flags &= ~SI_W_DADDR;
}
} else {
#ifdef USE_INET6
if (is->is_v == 6 &&
IN6_IS_ADDR_MULTICAST(&fi->fi_src.in6))
/*EMPTY*/;
else
#endif
{
is->is_dst = fi->fi_src;
is->is_flags &= ~SI_W_DADDR;
}
}
}
if ((is->is_flags & (SI_WILDA|SI_WILDP)) == 0) {
ATOMIC_DECL(ips_stats.iss_wild);
}
}
flx = fin->fin_flx & cmask;
cflx = is->is_flx[out][rev];
/*
* Match up any flags set from IP options.
*/
if ((cflx && (flx != (cflx & cmask))) ||
((fin->fin_optmsk & is->is_optmsk) != is->is_opt) ||
((fin->fin_secmsk & is->is_secmsk) != is->is_sec) ||
((fin->fin_auth & is->is_authmsk) != is->is_auth))
return NULL;
/*
* Only one of the source or destination port can be flagged as a
* wildcard. When filling it in, fill in a copy of the matched entry
* if it has the cloning flag set.
*/
if ((fin->fin_flx & FI_IGNORE) != 0) {
fin->fin_rev = rev;
return is;
}
if ((flags & (SI_W_SPORT|SI_W_DPORT))) {
if ((flags & SI_CLONE) != 0) {
is = fr_stclone(fin, tcp, is);
if (is == NULL)
return NULL;
} else {
ATOMIC_DECL(ips_stats.iss_wild);
}
if ((flags & SI_W_SPORT) != 0) {
if (rev == 0) {
is->is_sport = sp;
is->is_send = ntohl(tcp->th_seq);
} else {
is->is_sport = dp;
is->is_send = ntohl(tcp->th_ack);
}
is->is_maxsend = is->is_send + 1;
} else if ((flags & SI_W_DPORT) != 0) {
if (rev == 0) {
is->is_dport = dp;
is->is_dend = ntohl(tcp->th_ack);
} else {
is->is_dport = sp;
is->is_dend = ntohl(tcp->th_seq);
}
is->is_maxdend = is->is_dend + 1;
}
is->is_flags &= ~(SI_W_SPORT|SI_W_DPORT);
if ((flags & SI_CLONED) && ipstate_logging)
ipstate_log(is, ISL_CLONE);
}
ret = -1;
if (is->is_flx[out][rev] == 0)
is->is_flx[out][rev] = flx;
/*
* Check if the interface name for this "direction" is set and if not,
* fill it in.
*/
if (is->is_ifp[idx] == NULL &&
(*is->is_ifname[idx] == '\0' || *is->is_ifname[idx] == '*')) {
is->is_ifp[idx] = ifp;
COPYIFNAME(ifp, is->is_ifname[idx]);
}
fin->fin_rev = rev;
return is;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_checkicmpmatchingstate */
/* Returns: Nil */
/* Parameters: fin(I) - pointer to packet information */
/* */
/* If we've got an ICMP error message, using the information stored in the */
/* ICMP packet, look for a matching state table entry. */
/* */
/* If we return NULL then no lock on ipf_state is held. */
/* If we return non-null then a read-lock on ipf_state is held. */
/* ------------------------------------------------------------------------ */
static ipstate_t *fr_checkicmpmatchingstate(fin)
fr_info_t *fin;
{
ipstate_t *is, **isp;
u_short sport, dport;
u_char pr;
int backward, i, oi;
i6addr_t dst, src;
struct icmp *ic;
u_short savelen;
icmphdr_t *icmp;
fr_info_t ofin;
tcphdr_t *tcp;
int type, len;
ip_t *oip;
u_int hv;
/*
* 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 ((fin->fin_v != 4) || (fin->fin_hlen != sizeof(ip_t)) ||
(fin->fin_plen < ICMPERR_MINPKTLEN))
return NULL;
ic = fin->fin_dp;
type = ic->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 *)ic + ICMPERR_ICMPHLEN);
/*
* Check if the at least the old IP header (with options) and
* 8 bytes of payload is present.
*/
if (fin->fin_plen < ICMPERR_MAXPKTLEN + ((IP_HL(oip) - 5) << 2))
return NULL;
/*
* Sanity Checks.
*/
len = fin->fin_dlen - ICMPERR_ICMPHLEN;
if ((len <= 0) || ((IP_HL(oip) << 2) > len))
return NULL;
/*
* Is the buffer big enough for all of it ? It's the size of the IP
* header claimed in the encapsulated part which is of concern. It
* may be too big to be in this buffer but not so big that it's
* outside the ICMP packet, leading to TCP deref's causing problems.
* This is possible because we don't know how big oip_hl is when we
* do the pullup early in fr_check() and thus can't guarantee it is
* all here now.
*/
#ifdef _KERNEL
{
mb_t *m;
m = fin->fin_m;
# if defined(MENTAT)
if ((char *)oip + len > (char *)m->b_wptr)
return NULL;
# else
if ((char *)oip + len > (char *)fin->fin_ip + m->m_len)
return NULL;
# endif
}
#endif
bcopy((char *)fin, (char *)&ofin, sizeof(fin));
/*
* in the IPv4 case we must zero the i6addr union otherwise
* the IP6_EQ and IP6_NEQ macros produce the wrong results because
* of the 'junk' in the unused part of the union
*/
bzero((char *)&src, sizeof(src));
bzero((char *)&dst, sizeof(dst));
/*
* we make an fin entry to be able to feed it to
* matchsrcdst note that not all fields are encessary
* but this is the cleanest way. Note further we fill
* in fin_mp such that if someone uses it we'll get
* a kernel panic. fr_matchsrcdst does not use this.
*
* watch out here, as ip is in host order and oip in network
* order. Any change we make must be undone afterwards, like
* oip->ip_off - it is still in network byte order so fix it.
*/
savelen = oip->ip_len;
oip->ip_len = len;
oip->ip_off = htons(oip->ip_off);
ofin.fin_flx = FI_NOCKSUM;
ofin.fin_v = 4;
ofin.fin_ip = oip;
ofin.fin_m = NULL; /* if dereferenced, panic XXX */
ofin.fin_mp = NULL; /* if dereferenced, panic XXX */
ofin.fin_plen = fin->fin_dlen - ICMPERR_ICMPHLEN;
(void) fr_makefrip(IP_HL(oip) << 2, oip, &ofin);
ofin.fin_ifp = fin->fin_ifp;
ofin.fin_out = !fin->fin_out;
/*
* Reset the short and bad flag here because in fr_matchsrcdst()
* the flags for the current packet (fin_flx) are compared against
* those for the existing session.
*/
ofin.fin_flx &= ~(FI_BAD|FI_SHORT);
/*
* Put old values of ip_len and ip_off back as we don't know
* if we have to forward the packet (or process it again.
*/
oip->ip_len = savelen;
oip->ip_off = htons(oip->ip_off);
switch (oip->ip_p)
{
case IPPROTO_ICMP :
icmp = (icmphdr_t *)((char *)oip + (IP_HL(oip) << 2));
/*
* an ICMP error can only be generated as a result of an
* ICMP query, not as the response on an ICMP error
*
* XXX theoretically ICMP_ECHOREP and the other reply's are
* ICMP query's as well, but adding them here seems strange XXX
*/
if ((icmp->icmp_type != ICMP_ECHO) &&
(icmp->icmp_type != ICMP_TSTAMP) &&
(icmp->icmp_type != ICMP_IREQ) &&
(icmp->icmp_type != ICMP_MASKREQ))
return NULL;
/*
* perform a lookup of the ICMP packet in the state table
*/
hv = (pr = oip->ip_p);
src.in4 = oip->ip_src;
hv += src.in4.s_addr;
dst.in4 = oip->ip_dst;
hv += dst.in4.s_addr;
hv += icmp->icmp_id;
hv = DOUBLE_HASH(hv);
READ_ENTER(&ipf_state);
for (isp = &ips_table[hv]; ((is = *isp) != NULL); ) {
isp = &is->is_hnext;
if ((is->is_p != pr) || (is->is_v != 4))
continue;
if (is->is_pass & FR_NOICMPERR)
continue;
is = fr_matchsrcdst(&ofin, is, &src, &dst,
NULL, FI_ICMPCMP);
if (is != NULL) {
if ((is->is_pass & FR_NOICMPERR) != 0) {
RWLOCK_EXIT(&ipf_state);
return NULL;
}
/*
* i : the index of this packet (the icmp
* unreachable)
* oi : the index of the original packet found
* in the icmp header (i.e. the packet
* causing this icmp)
* backward : original packet was backward
* compared to the state
*/
backward = IP6_NEQ(&is->is_src, &src);
fin->fin_rev = !backward;
i = (!backward << 1) + fin->fin_out;
oi = (backward << 1) + ofin.fin_out;
if (is->is_icmppkts[i] > is->is_pkts[oi])
continue;
ips_stats.iss_hits++;
is->is_icmppkts[i]++;
return is;
}
}
RWLOCK_EXIT(&ipf_state);
return NULL;
case IPPROTO_TCP :
case IPPROTO_UDP :
break;
default :
return NULL;
}
tcp = (tcphdr_t *)((char *)oip + (IP_HL(oip) << 2));
dport = tcp->th_dport;
sport = tcp->th_sport;
hv = (pr = oip->ip_p);
src.in4 = oip->ip_src;
hv += src.in4.s_addr;
dst.in4 = oip->ip_dst;
hv += dst.in4.s_addr;
hv += dport;
hv += sport;
hv = DOUBLE_HASH(hv);
READ_ENTER(&ipf_state);
for (isp = &ips_table[hv]; ((is = *isp) != NULL); ) {
isp = &is->is_hnext;
/*
* Only allow this icmp though if the
* encapsulated packet was allowed through the
* other way around. Note that the minimal amount
* of info present does not allow for checking against
* tcp internals such as seq and ack numbers. Only the
* ports are known to be present and can be even if the
* short flag is set.
*/
if ((is->is_p == pr) && (is->is_v == 4) &&
(is = fr_matchsrcdst(&ofin, is, &src, &dst,
tcp, FI_ICMPCMP))) {
/*
* i : the index of this packet (the icmp unreachable)
* oi : the index of the original packet found in the
* icmp header (i.e. the packet causing this icmp)
* backward : original packet was backward compared to
* the state
*/
backward = IP6_NEQ(&is->is_src, &src);
fin->fin_rev = !backward;
i = (!backward << 1) + fin->fin_out;
oi = (backward << 1) + ofin.fin_out;
if (((is->is_pass & FR_NOICMPERR) != 0) ||
(is->is_icmppkts[i] > is->is_pkts[oi]))
break;
ips_stats.iss_hits++;
is->is_icmppkts[i]++;
/*
* we deliberately do not touch the timeouts
* for the accompanying state table entry.
* It remains to be seen if that is correct. XXX
*/
return is;
}
}
RWLOCK_EXIT(&ipf_state);
return NULL;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_ipsmove */
/* Returns: Nil */
/* Parameters: is(I) - pointer to state table entry */
/* hv(I) - new hash value for state table entry */
/* Write Locks: ipf_state */
/* */
/* Move a state entry from one position in the hash table to another. */
/* ------------------------------------------------------------------------ */
static void fr_ipsmove(is, hv)
ipstate_t *is;
u_int hv;
{
ipstate_t **isp;
u_int hvm;
ASSERT(rw_read_locked(&ipf_state.ipf_lk) == 0);
hvm = is->is_hv;
/*
* Remove the hash from the old location...
*/
isp = is->is_phnext;
if (is->is_hnext)
is->is_hnext->is_phnext = isp;
*isp = is->is_hnext;
if (ips_table[hvm] == NULL)
ips_stats.iss_inuse--;
ips_stats.iss_bucketlen[hvm]--;
/*
* ...and put the hash in the new one.
*/
hvm = DOUBLE_HASH(hv);
is->is_hv = hvm;
isp = &ips_table[hvm];
if (*isp)
(*isp)->is_phnext = &is->is_hnext;
else
ips_stats.iss_inuse++;
ips_stats.iss_bucketlen[hvm]++;
is->is_phnext = isp;
is->is_hnext = *isp;
*isp = is;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_stlookup */
/* Returns: ipstate_t* - NULL == no matching state found, */
/* else pointer to state information is returned */
/* Parameters: fin(I) - pointer to packet information */
/* tcp(I) - pointer to TCP/UDP header. */
/* */
/* Search the state table for a matching entry to the packet described by */
/* the contents of *fin. */
/* */
/* If we return NULL then no lock on ipf_state is held. */
/* If we return non-null then a read-lock on ipf_state is held. */
/* ------------------------------------------------------------------------ */
ipstate_t *fr_stlookup(fin, tcp, ifqp)
fr_info_t *fin;
tcphdr_t *tcp;
ipftq_t **ifqp;
{
u_int hv, hvm, pr, v, tryagain;
ipstate_t *is, **isp;
u_short dport, sport;
i6addr_t src, dst;
struct icmp *ic;
ipftq_t *ifq;
int oow;
is = NULL;
ifq = NULL;
tcp = fin->fin_dp;
ic = (struct icmp *)tcp;
hv = (pr = fin->fin_fi.fi_p);
src = fin->fin_fi.fi_src;
dst = fin->fin_fi.fi_dst;
hv += src.in4.s_addr;
hv += dst.in4.s_addr;
v = fin->fin_fi.fi_v;
#ifdef USE_INET6
if (v == 6) {
hv += fin->fin_fi.fi_src.i6[1];
hv += fin->fin_fi.fi_src.i6[2];
hv += fin->fin_fi.fi_src.i6[3];
if ((fin->fin_p == IPPROTO_ICMPV6) &&
IN6_IS_ADDR_MULTICAST(&fin->fin_fi.fi_dst.in6)) {
hv -= dst.in4.s_addr;
} else {
hv += fin->fin_fi.fi_dst.i6[1];
hv += fin->fin_fi.fi_dst.i6[2];
hv += fin->fin_fi.fi_dst.i6[3];
}
}
#endif
/*
* Search the hash table for matching packet header info.
*/
switch (pr)
{
#ifdef USE_INET6
case IPPROTO_ICMPV6 :
tryagain = 0;
if (v == 6) {
if ((ic->icmp_type == ICMP6_ECHO_REQUEST) ||
(ic->icmp_type == ICMP6_ECHO_REPLY)) {
hv += ic->icmp_id;
}
}
READ_ENTER(&ipf_state);
icmp6again:
hvm = DOUBLE_HASH(hv);
for (isp = &ips_table[hvm]; ((is = *isp) != NULL); ) {
isp = &is->is_hnext;
if ((is->is_p != pr) || (is->is_v != v))
continue;
is = fr_matchsrcdst(fin, is, &src, &dst, NULL, FI_CMP);
if (is != NULL &&
fr_matchicmpqueryreply(v, &is->is_icmp,
ic, fin->fin_rev)) {
if (fin->fin_rev)
ifq = &ips_icmpacktq;
else
ifq = &ips_icmptq;
break;
}
}
if (is != NULL) {
if ((tryagain != 0) && !(is->is_flags & SI_W_DADDR)) {
hv += fin->fin_fi.fi_src.i6[0];
hv += fin->fin_fi.fi_src.i6[1];
hv += fin->fin_fi.fi_src.i6[2];
hv += fin->fin_fi.fi_src.i6[3];
fr_ipsmove(is, hv);
MUTEX_DOWNGRADE(&ipf_state);
}
break;
}
RWLOCK_EXIT(&ipf_state);
/*
* No matching icmp state entry. Perhaps this is a
* response to another state entry.
*
* XXX With some ICMP6 packets, the "other" address is already
* in the packet, after the ICMP6 header, and this could be
* used in place of the multicast address. However, taking
* advantage of this requires some significant code changes
* to handle the specific types where that is the case.
*/
if ((ips_stats.iss_wild != 0) && (v == 6) && (tryagain == 0) &&
!IN6_IS_ADDR_MULTICAST(&fin->fin_fi.fi_src.in6)) {
hv -= fin->fin_fi.fi_src.i6[0];
hv -= fin->fin_fi.fi_src.i6[1];
hv -= fin->fin_fi.fi_src.i6[2];
hv -= fin->fin_fi.fi_src.i6[3];
tryagain = 1;
WRITE_ENTER(&ipf_state);
goto icmp6again;
}
is = fr_checkicmp6matchingstate(fin);
if (is != NULL)
return is;
break;
#endif
case IPPROTO_ICMP :
if (v == 4) {
hv += ic->icmp_id;
}
hv = DOUBLE_HASH(hv);
READ_ENTER(&ipf_state);
for (isp = &ips_table[hv]; ((is = *isp) != NULL); ) {
isp = &is->is_hnext;
if ((is->is_p != pr) || (is->is_v != v))
continue;
is = fr_matchsrcdst(fin, is, &src, &dst, NULL, FI_CMP);
if (is != NULL &&
fr_matchicmpqueryreply(v, &is->is_icmp,
ic, fin->fin_rev)) {
if (fin->fin_rev)
ifq = &ips_icmpacktq;
else
ifq = &ips_icmptq;
break;
}
}
if (is == NULL) {
RWLOCK_EXIT(&ipf_state);
}
break;
case IPPROTO_TCP :
case IPPROTO_UDP :
ifqp = NULL;
sport = htons(fin->fin_data[0]);
hv += sport;
dport = htons(fin->fin_data[1]);
hv += dport;
oow = 0;
tryagain = 0;
READ_ENTER(&ipf_state);
retry_tcpudp:
hvm = DOUBLE_HASH(hv);
for (isp = &ips_table[hvm]; ((is = *isp) != NULL); ) {
isp = &is->is_hnext;
if ((is->is_p != pr) || (is->is_v != v))
continue;
fin->fin_flx &= ~FI_OOW;
is = fr_matchsrcdst(fin, is, &src, &dst, tcp, FI_CMP);
if (is != NULL) {
if (pr == IPPROTO_TCP) {
if (!fr_tcpstate(fin, tcp, is)) {
oow |= fin->fin_flx & FI_OOW;
continue;
}
}
break;
}
}
if (is != NULL) {
if (tryagain &&
!(is->is_flags & (SI_CLONE|SI_WILDP|SI_WILDA))) {
hv += dport;
hv += sport;
fr_ipsmove(is, hv);
MUTEX_DOWNGRADE(&ipf_state);
}
break;
}
RWLOCK_EXIT(&ipf_state);
if (!tryagain && ips_stats.iss_wild) {
hv -= dport;
hv -= sport;
tryagain = 1;
WRITE_ENTER(&ipf_state);
goto retry_tcpudp;
}
fin->fin_flx |= oow;
break;
#if 0
case IPPROTO_GRE :
gre = fin->fin_dp;
if (GRE_REV(gre->gr_flags) == 1) {
hv += gre->gr_call;
}
/* FALLTHROUGH */
#endif
default :
ifqp = NULL;
hvm = DOUBLE_HASH(hv);
READ_ENTER(&ipf_state);
for (isp = &ips_table[hvm]; ((is = *isp) != NULL); ) {
isp = &is->is_hnext;
if ((is->is_p != pr) || (is->is_v != v))
continue;
is = fr_matchsrcdst(fin, is, &src, &dst, NULL, FI_CMP);
if (is != NULL) {
ifq = &ips_iptq;
break;
}
}
if (is == NULL) {
RWLOCK_EXIT(&ipf_state);
}
break;
}
if ((is != NULL) && ((is->is_sti.tqe_flags & TQE_RULEBASED) != 0) &&
(is->is_tqehead[fin->fin_rev] != NULL))
ifq = is->is_tqehead[fin->fin_rev];
if (ifq != NULL && ifqp != NULL)
*ifqp = ifq;
return is;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_updatestate */
/* Returns: Nil */
/* Parameters: fin(I) - pointer to packet information */
/* is(I) - pointer to state table entry */
/* Read Locks: ipf_state */
/* */
/* Updates packet and byte counters for a newly received packet. Seeds the */
/* fragment cache with a new entry as required. */
/* ------------------------------------------------------------------------ */
void fr_updatestate(fin, is, ifq)
fr_info_t *fin;
ipstate_t *is;
ipftq_t *ifq;
{
ipftqent_t *tqe;
int i, pass;
i = (fin->fin_rev << 1) + fin->fin_out;
/*
* For TCP packets, ifq == NULL. For all others, check if this new
* queue is different to the last one it was on and move it if so.
*/
tqe = &is->is_sti;
MUTEX_ENTER(&is->is_lock);
if ((tqe->tqe_flags & TQE_RULEBASED) != 0)
ifq = is->is_tqehead[fin->fin_rev];
if (ifq != NULL)
fr_movequeue(tqe, tqe->tqe_ifq, ifq);
is->is_pkts[i]++;
is->is_bytes[i] += fin->fin_plen;
MUTEX_EXIT(&is->is_lock);
#ifdef IPFILTER_SYNC
if (is->is_flags & IS_STATESYNC)
ipfsync_update(SMC_STATE, fin, is->is_sync);
#endif
ATOMIC_INCL(ips_stats.iss_hits);
fin->fin_fr = is->is_rule;
/*
* If this packet is a fragment and the rule says to track fragments,
* then create a new fragment cache entry.
*/
pass = is->is_pass;
if ((fin->fin_flx & FI_FRAG) && FR_ISPASS(pass))
(void) fr_newfrag(fin, pass ^ FR_KEEPSTATE);
}
/* ------------------------------------------------------------------------ */
/* Function: fr_checkstate */
/* Returns: frentry_t* - NULL == search failed, */
/* else pointer to rule for matching state */
/* Parameters: ifp(I) - pointer to interface */
/* passp(I) - pointer to filtering result flags */
/* */
/* Check if a packet is associated with an entry in the state table. */
/* ------------------------------------------------------------------------ */
frentry_t *fr_checkstate(fin, passp)
fr_info_t *fin;
u_32_t *passp;
{
ipstate_t *is;
frentry_t *fr;
tcphdr_t *tcp;
ipftq_t *ifq;
u_int pass;
if (fr_state_lock || (ips_list == NULL) ||
(fin->fin_flx & (FI_SHORT|FI_STATE|FI_FRAGBODY|FI_BAD)))
return NULL;
is = NULL;
if ((fin->fin_flx & FI_TCPUDP) ||
(fin->fin_fi.fi_p == IPPROTO_ICMP)
#ifdef USE_INET6
|| (fin->fin_fi.fi_p == IPPROTO_ICMPV6)
#endif
)
tcp = fin->fin_dp;
else
tcp = NULL;
/*
* Search the hash table for matching packet header info.
*/
ifq = NULL;
is = fin->fin_state;
if (is == NULL)
is = fr_stlookup(fin, tcp, &ifq);
switch (fin->fin_p)
{
#ifdef USE_INET6
case IPPROTO_ICMPV6 :
if (is != NULL)
break;
if (fin->fin_v == 6) {
is = fr_checkicmp6matchingstate(fin);
if (is != NULL)
goto matched;
}
break;
#endif
case IPPROTO_ICMP :
if (is != NULL)
break;
/*
* No matching icmp state entry. Perhaps this is a
* response to another state entry.
*/
is = fr_checkicmpmatchingstate(fin);
if (is != NULL)
goto matched;
break;
case IPPROTO_TCP :
if (is == NULL)
break;
if (is->is_pass & FR_NEWISN) {
if (fin->fin_out == 0)
fr_fixinisn(fin, is);
else if (fin->fin_out == 1)
fr_fixoutisn(fin, is);
}
break;
default :
if (fin->fin_rev)
ifq = &ips_udpacktq;
else
ifq = &ips_udptq;
break;
}
if (is == NULL) {
ATOMIC_INCL(ips_stats.iss_miss);
return NULL;
}
matched:
fr = is->is_rule;
if (fr != NULL) {
if ((fin->fin_out == 0) && (fr->fr_nattag.ipt_num[0] != 0)) {
if (fin->fin_nattag == NULL)
return NULL;
if (fr_matchtag(&fr->fr_nattag, fin->fin_nattag) != 0)
return NULL;
}
(void) strncpy(fin->fin_group, fr->fr_group, FR_GROUPLEN);
fin->fin_icode = fr->fr_icode;
}
fin->fin_rule = is->is_rulen;
pass = is->is_pass;
fr_updatestate(fin, is, ifq);
if (fin->fin_out == 1)
fin->fin_nat = is->is_nat[fin->fin_rev];
fin->fin_state = is;
is->is_touched = fr_ticks;
MUTEX_ENTER(&is->is_lock);
is->is_ref++;
MUTEX_EXIT(&is->is_lock);
RWLOCK_EXIT(&ipf_state);
fin->fin_flx |= FI_STATE;
if ((pass & FR_LOGFIRST) != 0)
pass &= ~(FR_LOGFIRST|FR_LOG);
*passp = pass;
return fr;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_fixoutisn */
/* Returns: Nil */
/* Parameters: fin(I) - pointer to packet information */
/* is(I) - pointer to master state structure */
/* */
/* Called only for outbound packets, adjusts the sequence number and the */
/* TCP checksum to match that change. */
/* ------------------------------------------------------------------------ */
static void fr_fixoutisn(fin, is)
fr_info_t *fin;
ipstate_t *is;
{
tcphdr_t *tcp;
int rev;
u_32_t seq;
tcp = fin->fin_dp;
rev = fin->fin_rev;
if ((is->is_flags & IS_ISNSYN) != 0) {
if (rev == 0) {
seq = ntohl(tcp->th_seq);
seq += is->is_isninc[0];
tcp->th_seq = htonl(seq);
fix_outcksum(fin, &tcp->th_sum, is->is_sumd[0]);
}
}
if ((is->is_flags & IS_ISNACK) != 0) {
if (rev == 1) {
seq = ntohl(tcp->th_seq);
seq += is->is_isninc[1];
tcp->th_seq = htonl(seq);
fix_outcksum(fin, &tcp->th_sum, is->is_sumd[1]);
}
}
}
/* ------------------------------------------------------------------------ */
/* Function: fr_fixinisn */
/* Returns: Nil */
/* Parameters: fin(I) - pointer to packet information */
/* is(I) - pointer to master state structure */
/* */
/* Called only for inbound packets, adjusts the acknowledge number and the */
/* TCP checksum to match that change. */
/* ------------------------------------------------------------------------ */
static void fr_fixinisn(fin, is)
fr_info_t *fin;
ipstate_t *is;
{
tcphdr_t *tcp;
int rev;
u_32_t ack;
tcp = fin->fin_dp;
rev = fin->fin_rev;
if ((is->is_flags & IS_ISNSYN) != 0) {
if (rev == 1) {
ack = ntohl(tcp->th_ack);
ack -= is->is_isninc[0];
tcp->th_ack = htonl(ack);
fix_incksum(fin, &tcp->th_sum, is->is_sumd[0]);
}
}
if ((is->is_flags & IS_ISNACK) != 0) {
if (rev == 0) {
ack = ntohl(tcp->th_ack);
ack -= is->is_isninc[1];
tcp->th_ack = htonl(ack);
fix_incksum(fin, &tcp->th_sum, is->is_sumd[1]);
}
}
}
/* ------------------------------------------------------------------------ */
/* Function: fr_statesync */
/* Returns: Nil */
/* Parameters: ifp(I) - pointer to interface */
/* */
/* Walk through all state entries and if an interface pointer match is */
/* found then look it up again, based on its name in case the pointer has */
/* changed since last time. */
/* */
/* If ifp is passed in as being non-null then we are only doing updates for */
/* existing, matching, uses of it. */
/* ------------------------------------------------------------------------ */
void fr_statesync(ifp)
void *ifp;
{
ipstate_t *is;
int i;
if (fr_running <= 0)
return;
WRITE_ENTER(&ipf_state);
if (fr_running <= 0) {
RWLOCK_EXIT(&ipf_state);
return;
}
for (is = ips_list; is; is = is->is_next) {
/*
* Look up all the interface names in the state entry.
*/
for (i = 0; i < 4; i++) {
if (ifp == NULL || ifp == is->is_ifp[i])
is->is_ifp[i] = fr_resolvenic(is->is_ifname[i],
is->is_v);
}
}
RWLOCK_EXIT(&ipf_state);
}
/* ------------------------------------------------------------------------ */
/* Function: fr_delstate */
/* Returns: Nil */
/* Parameters: is(I) - pointer to state structure to delete */
/* why(I) - if not 0, log reason why it was deleted */
/* Write Locks: ipf_state */
/* */
/* Deletes a state entry from the enumerated list as well as the hash table */
/* and timeout queue lists. Make adjustments to hash table statistics and */
/* global counters as required. */
/* ------------------------------------------------------------------------ */
static void fr_delstate(is, why)
ipstate_t *is;
int why;
{
ASSERT(rw_read_locked(&ipf_state.ipf_lk) == 0);
/*
* Since we want to delete this, remove it from the state table,
* where it can be found & used, first.
*/
if (is->is_pnext != NULL) {
*is->is_pnext = is->is_next;
if (is->is_next != NULL)
is->is_next->is_pnext = is->is_pnext;
is->is_pnext = NULL;
is->is_next = NULL;
}
if (is->is_phnext != NULL) {
*is->is_phnext = is->is_hnext;
if (is->is_hnext != NULL)
is->is_hnext->is_phnext = is->is_phnext;
if (ips_table[is->is_hv] == NULL)
ips_stats.iss_inuse--;
ips_stats.iss_bucketlen[is->is_hv]--;
is->is_phnext = NULL;
is->is_hnext = NULL;
}
/*
* Because ips_stats.iss_wild is a count of entries in the state
* table that have wildcard flags set, only decerement it once
* and do it here.
*/
if (is->is_flags & (SI_WILDP|SI_WILDA)) {
if (!(is->is_flags & SI_CLONED)) {
ATOMIC_DECL(ips_stats.iss_wild);
}
is->is_flags &= ~(SI_WILDP|SI_WILDA);
}
/*
* Next, remove it from the timeout queue it is in.
*/
fr_deletequeueentry(&is->is_sti);
if (is->is_me != NULL) {
*is->is_me = NULL;
is->is_me = NULL;
}
/*
* If it is still in use by something else, do not go any further,
* but note that at this point it is now an orphan.
*/
is->is_ref--;
if (is->is_ref > 0)
return;
if (is->is_tqehead[0] != NULL) {
if (fr_deletetimeoutqueue(is->is_tqehead[0]) == 0)
fr_freetimeoutqueue(is->is_tqehead[0]);
}
if (is->is_tqehead[1] != NULL) {
if (fr_deletetimeoutqueue(is->is_tqehead[1]) == 0)
fr_freetimeoutqueue(is->is_tqehead[1]);
}
#ifdef IPFILTER_SYNC
if (is->is_sync)
ipfsync_del(is->is_sync);
#endif
#ifdef IPFILTER_SCAN
(void) ipsc_detachis(is);
#endif
if (ipstate_logging != 0 && why != 0)
ipstate_log(is, why);
if (is->is_rule != NULL) {
is->is_rule->fr_statecnt--;
(void)fr_derefrule(&is->is_rule);
}
MUTEX_DESTROY(&is->is_lock);
KFREE(is);
ips_num--;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_timeoutstate */
/* Returns: Nil */
/* Parameters: Nil */
/* */
/* Slowly expire held state for thingslike UDP and ICMP. The algorithm */
/* used here is to keep the queue sorted with the oldest things at the top */
/* and the youngest at the bottom. So if the top one doesn't need to be */
/* expired then neither will any under it. */
/* ------------------------------------------------------------------------ */
void fr_timeoutstate()
{
ipftq_t *ifq, *ifqnext;
ipftqent_t *tqe, *tqn;
ipstate_t *is;
#if defined(USE_SPL) && defined(_KERNEL)
int s;
#endif
SPL_NET(s);
WRITE_ENTER(&ipf_state);
for (ifq = ips_tqtqb; ifq != NULL; ifq = ifq->ifq_next)
for (tqn = ifq->ifq_head; ((tqe = tqn) != NULL); ) {
if (tqe->tqe_die > fr_ticks)
break;
tqn = tqe->tqe_next;
is = tqe->tqe_parent;
fr_delstate(is, ISL_EXPIRE);
}
for (ifq = ips_utqe; ifq != NULL; ifq = ifqnext) {
ifqnext = ifq->ifq_next;
for (tqn = ifq->ifq_head; ((tqe = tqn) != NULL); ) {
if (tqe->tqe_die > fr_ticks)
break;
tqn = tqe->tqe_next;
is = tqe->tqe_parent;
fr_delstate(is, ISL_EXPIRE);
}
}
for (ifq = ips_utqe; ifq != NULL; ifq = ifqnext) {
ifqnext = ifq->ifq_next;
if (((ifq->ifq_flags & IFQF_DELETE) != 0) &&
(ifq->ifq_ref == 0)) {
fr_freetimeoutqueue(ifq);
}
}
if (fr_state_doflush) {
(void) fr_state_flush(2, 0);
fr_state_doflush = 0;
}
RWLOCK_EXIT(&ipf_state);
SPL_X(s);
}
/* ------------------------------------------------------------------------ */
/* Function: fr_state_flush */
/* Returns: int - 0 == success, -1 == failure */
/* Parameters: Nil */
/* Write Locks: ipf_state */
/* */
/* Flush state tables. Three actions currently defined: */
/* which == 0 : flush all state table entries */
/* which == 1 : flush TCP connections which have started to close but are */
/* stuck for some reason. */
/* which == 2 : flush TCP connections which have been idle for a long time, */
/* starting at > 4 days idle and working back in successive half-*/
/* days to at most 12 hours old. If this fails to free enough */
/* slots then work backwards in half hour slots to 30 minutes. */
/* If that too fails, then work backwards in 30 second intervals */
/* for the last 30 minutes to at worst 30 seconds idle. */
/* ------------------------------------------------------------------------ */
static int fr_state_flush(which, proto)
int which, proto;
{
ipftq_t *ifq, *ifqnext;
ipftqent_t *tqe, *tqn;
ipstate_t *is, **isp;
int delete, removed;
long try, maxtick;
u_long interval;
#if defined(_KERNEL) && !defined(MENTAT) && defined(USE_SPL)
int s;
#endif
removed = 0;
SPL_NET(s);
for (isp = &ips_list; ((is = *isp) != NULL); ) {
delete = 0;
if ((proto != 0) && (is->is_v != proto)) {
isp = &is->is_next;
continue;
}
switch (which)
{
case 0 :
delete = 1;
break;
case 1 :
case 2 :
if (is->is_p != IPPROTO_TCP)
break;
if ((is->is_state[0] != IPF_TCPS_ESTABLISHED) ||
(is->is_state[1] != IPF_TCPS_ESTABLISHED))
delete = 1;
break;
}
if (delete) {
if (is->is_p == IPPROTO_TCP)
ips_stats.iss_fin++;
else
ips_stats.iss_expire++;
fr_delstate(is, ISL_FLUSH);
removed++;
} else
isp = &is->is_next;
}
if (which != 2) {
SPL_X(s);
return removed;
}
/*
* Asked to remove inactive entries because the table is full, try
* again, 3 times, if first attempt failed with a different criteria
* each time. The order tried in must be in decreasing age.
* Another alternative is to implement random drop and drop N entries
* at random until N have been freed up.
*/
if (fr_ticks - ips_last_force_flush < IPF_TTLVAL(5))
goto force_flush_skipped;
ips_last_force_flush = fr_ticks;
if (fr_ticks > IPF_TTLVAL(43200))
interval = IPF_TTLVAL(43200);
else if (fr_ticks > IPF_TTLVAL(1800))
interval = IPF_TTLVAL(1800);
else if (fr_ticks > IPF_TTLVAL(30))
interval = IPF_TTLVAL(30);
else
interval = IPF_TTLVAL(10);
try = fr_ticks - (fr_ticks - interval);
if (try < 0)
goto force_flush_skipped;
while (removed == 0) {
maxtick = fr_ticks - interval;
if (maxtick < 0)
break;
while (try < maxtick) {
for (ifq = ips_tqtqb; ifq != NULL;
ifq = ifq->ifq_next) {
for (tqn = ifq->ifq_head;
((tqe = tqn) != NULL); ) {
if (tqe->tqe_die > try)
break;
tqn = tqe->tqe_next;
is = tqe->tqe_parent;
fr_delstate(is, ISL_EXPIRE);
removed++;
}
}
for (ifq = ips_utqe; ifq != NULL; ifq = ifqnext) {
ifqnext = ifq->ifq_next;
for (tqn = ifq->ifq_head;
((tqe = tqn) != NULL); ) {
if (tqe->tqe_die > try)
break;
tqn = tqe->tqe_next;
is = tqe->tqe_parent;
fr_delstate(is, ISL_EXPIRE);
removed++;
}
}
if (try + interval > maxtick)
break;
try += interval;
}
if (removed == 0) {
if (interval == IPF_TTLVAL(43200)) {
interval = IPF_TTLVAL(1800);
} else if (interval == IPF_TTLVAL(1800)) {
interval = IPF_TTLVAL(30);
} else if (interval == IPF_TTLVAL(30)) {
interval = IPF_TTLVAL(10);
} else {
break;
}
}
}
force_flush_skipped:
SPL_X(s);
return removed;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_tcp_age */
/* Returns: int - 1 == state transition made, 0 == no change (rejected) */
/* Parameters: tq(I) - pointer to timeout queue information */
/* fin(I) - pointer to packet information */
/* tqtab(I) - TCP timeout queue table this is in */
/* flags(I) - flags from state/NAT entry */
/* */
/* Rewritten by Arjan de Vet <Arjan.deVet@adv.iae.nl>, 2000-07-29: */
/* */
/* - (try to) base state transitions on real evidence only, */
/* i.e. packets that are sent and have been received by ipfilter; */
/* diagram 18.12 of TCP/IP volume 1 by W. Richard Stevens was used. */
/* */
/* - deal with half-closed connections correctly; */
/* */
/* - store the state of the source in state[0] such that ipfstat */
/* displays the state as source/dest instead of dest/source; the calls */
/* to fr_tcp_age have been changed accordingly. */
/* */
/* Internal Parameters: */
/* */
/* state[0] = state of source (host that initiated connection) */
/* state[1] = state of dest (host that accepted the connection) */
/* */
/* dir == 0 : a packet from source to dest */
/* dir == 1 : a packet from dest to source */
/* */
/* Locking: it is assumed that the parent of the tqe structure is locked. */
/* ------------------------------------------------------------------------ */
int fr_tcp_age(tqe, fin, tqtab, flags)
ipftqent_t *tqe;
fr_info_t *fin;
ipftq_t *tqtab;
int flags;
{
int dlen, ostate, nstate, rval, dir;
u_char tcpflags;
tcphdr_t *tcp;
tcp = fin->fin_dp;
rval = 0;
dir = fin->fin_rev;
tcpflags = tcp->th_flags;
dlen = fin->fin_plen - fin->fin_hlen - (TCP_OFF(tcp) << 2);
if (tcpflags & TH_RST) {
if (!(tcpflags & TH_PUSH) && !dlen)
nstate = IPF_TCPS_CLOSED;
else
nstate = IPF_TCPS_CLOSE_WAIT;
rval = 1;
} else {
ostate = tqe->tqe_state[1 - dir];
nstate = tqe->tqe_state[dir];
switch (nstate)
{
case IPF_TCPS_CLOSED: /* 0 */
if ((tcpflags & TH_OPENING) == TH_OPENING) {
/*
* 'dir' received an S and sends SA in
* response, CLOSED -> SYN_RECEIVED
*/
nstate = IPF_TCPS_SYN_RECEIVED;
rval = 1;
} else if ((tcpflags & TH_OPENING) == TH_SYN) {
/* 'dir' sent S, CLOSED -> SYN_SENT */
nstate = IPF_TCPS_SYN_SENT;
rval = 1;
}
/*
* the next piece of code makes it possible to get
* already established connections into the state table
* after a restart or reload of the filter rules; this
* does not work when a strict 'flags S keep state' is
* used for tcp connections of course
*/
if (((flags & IS_TCPFSM) == 0) &&
((tcpflags & TH_ACKMASK) == TH_ACK)) {
/*
* we saw an A, guess 'dir' is in ESTABLISHED
* mode
*/
switch (ostate)
{
case IPF_TCPS_CLOSED :
case IPF_TCPS_SYN_RECEIVED :
nstate = IPF_TCPS_HALF_ESTAB;
rval = 1;
break;
case IPF_TCPS_HALF_ESTAB :
case IPF_TCPS_ESTABLISHED :
nstate = IPF_TCPS_ESTABLISHED;
rval = 1;
break;
default :
break;
}
}
/*
* TODO: besides regular ACK packets we can have other
* packets as well; it is yet to be determined how we
* should initialize the states in those cases
*/
break;
case IPF_TCPS_LISTEN: /* 1 */
/* NOT USED */
break;
case IPF_TCPS_SYN_SENT: /* 2 */
if ((tcpflags & ~(TH_ECN|TH_CWR)) == TH_SYN) {
/*
* A retransmitted SYN packet. We do not reset
* the timeout here to fr_tcptimeout because a
* connection connect timeout does not renew
* after every packet that is sent. We need to
* set rval so as to indicate the packet has
* passed the check for its flags being valid
* in the TCP FSM. Setting rval to 2 has the
* result of not resetting the timeout.
*/
rval = 2;
} else if ((tcpflags & (TH_SYN|TH_FIN|TH_ACK)) ==
TH_ACK) {
/*
* we see an A from 'dir' which is in SYN_SENT
* state: 'dir' sent an A in response to an SA
* which it received, SYN_SENT -> ESTABLISHED
*/
nstate = IPF_TCPS_ESTABLISHED;
rval = 1;
} else if (tcpflags & TH_FIN) {
/*
* we see an F from 'dir' which is in SYN_SENT
* state and wants to close its side of the
* connection; SYN_SENT -> FIN_WAIT_1
*/
nstate = IPF_TCPS_FIN_WAIT_1;
rval = 1;
} else if ((tcpflags & TH_OPENING) == TH_OPENING) {
/*
* we see an SA from 'dir' which is already in
* SYN_SENT state, this means we have a
* simultaneous open; SYN_SENT -> SYN_RECEIVED
*/
nstate = IPF_TCPS_SYN_RECEIVED;
rval = 1;
}
break;
case IPF_TCPS_SYN_RECEIVED: /* 3 */
if ((tcpflags & (TH_SYN|TH_FIN|TH_ACK)) == TH_ACK) {
/*
* we see an A from 'dir' which was in
* SYN_RECEIVED state so it must now be in
* established state, SYN_RECEIVED ->
* ESTABLISHED
*/
nstate = IPF_TCPS_ESTABLISHED;
rval = 1;
} else if ((tcpflags & ~(TH_ECN|TH_CWR)) ==
TH_OPENING) {
/*
* We see an SA from 'dir' which is already in
* SYN_RECEIVED state.
*/
rval = 2;
} else if (tcpflags & TH_FIN) {
/*
* we see an F from 'dir' which is in
* SYN_RECEIVED state and wants to close its
* side of the connection; SYN_RECEIVED ->
* FIN_WAIT_1
*/
nstate = IPF_TCPS_FIN_WAIT_1;
rval = 1;
}
break;
case IPF_TCPS_HALF_ESTAB: /* 4 */
if (ostate >= IPF_TCPS_HALF_ESTAB) {
if ((tcpflags & TH_ACKMASK) == TH_ACK) {
nstate = IPF_TCPS_ESTABLISHED;
rval = 1;
}
}
break;
case IPF_TCPS_ESTABLISHED: /* 5 */
rval = 1;
if (tcpflags & TH_FIN) {
/*
* 'dir' closed its side of the connection;
* this gives us a half-closed connection;
* ESTABLISHED -> FIN_WAIT_1
*/
nstate = IPF_TCPS_FIN_WAIT_1;
} else if (tcpflags & TH_ACK) {
/*
* an ACK, should we exclude other flags here?
*/
if (ostate == IPF_TCPS_FIN_WAIT_1) {
/*
* We know the other side did an active
* close, so we are ACKing the recvd
* FIN packet (does the window matching
* code guarantee this?) and go into
* CLOSE_WAIT state; this gives us a
* half-closed connection
*/
nstate = IPF_TCPS_CLOSE_WAIT;
} else if (ostate < IPF_TCPS_CLOSE_WAIT) {
/*
* still a fully established
* connection reset timeout
*/
nstate = IPF_TCPS_ESTABLISHED;
}
}
break;
case IPF_TCPS_CLOSE_WAIT: /* 6 */
rval = 1;
if (tcpflags & TH_FIN) {
/*
* application closed and 'dir' sent a FIN,
* we're now going into LAST_ACK state
*/
nstate = IPF_TCPS_LAST_ACK;
} else {
/*
* we remain in CLOSE_WAIT because the other
* side has closed already and we did not
* close our side yet; reset timeout
*/
nstate = IPF_TCPS_CLOSE_WAIT;
}
break;
case IPF_TCPS_FIN_WAIT_1: /* 7 */
rval = 1;
if ((tcpflags & TH_ACK) &&
ostate > IPF_TCPS_CLOSE_WAIT) {
/*
* if the other side is not active anymore
* it has sent us a FIN packet that we are
* ack'ing now with an ACK; this means both
* sides have now closed the connection and
* we go into TIME_WAIT
*/
/*
* XXX: how do we know we really are ACKing
* the FIN packet here? does the window code
* guarantee that?
*/
nstate = IPF_TCPS_TIME_WAIT;
} else {
/*
* we closed our side of the connection
* already but the other side is still active
* (ESTABLISHED/CLOSE_WAIT); continue with
* this half-closed connection
*/
nstate = IPF_TCPS_FIN_WAIT_1;
}
break;
case IPF_TCPS_CLOSING: /* 8 */
/* NOT USED */
break;
case IPF_TCPS_LAST_ACK: /* 9 */
if (tcpflags & TH_ACK) {
if ((tcpflags & TH_PUSH) || dlen)
/*
* there is still data to be delivered,
* reset timeout
*/
rval = 1;
else
rval = 2;
}
/*
* we cannot detect when we go out of LAST_ACK state to
* CLOSED because that is based on the reception of ACK
* packets; ipfilter can only detect that a packet
* has been sent by a host
*/
break;
case IPF_TCPS_FIN_WAIT_2: /* 10 */
rval = 1;
if ((tcpflags & TH_OPENING) == TH_OPENING)
nstate = IPF_TCPS_SYN_RECEIVED;
else if (tcpflags & TH_SYN)
nstate = IPF_TCPS_SYN_SENT;
break;
case IPF_TCPS_TIME_WAIT: /* 11 */
/* we're in 2MSL timeout now */
rval = 1;
break;
default :
#if defined(_KERNEL)
# if SOLARIS
cmn_err(CE_NOTE,
"tcp %lx flags %x si %lx nstate %d ostate %d\n",
(u_long)tcp, tcpflags, (u_long)tqe,
nstate, ostate);
# else
printf("tcp %lx flags %x si %lx nstate %d ostate %d\n",
(u_long)tcp, tcpflags, (u_long)tqe,
nstate, ostate);
# endif
# ifdef DIAGNOSTIC
panic("invalid TCP state");
# endif
#else
abort();
#endif
break;
}
}
/*
* If rval == 2 then do not update the queue position, but treat the
* packet as being ok.
*/
if (rval == 2)
rval = 1;
else if (rval == 1) {
tqe->tqe_state[dir] = nstate;
if ((tqe->tqe_flags & TQE_RULEBASED) == 0)
fr_movequeue(tqe, tqe->tqe_ifq, tqtab + nstate);
}
return rval;
}
/* ------------------------------------------------------------------------ */
/* Function: ipstate_log */
/* Returns: Nil */
/* Parameters: is(I) - pointer to state structure */
/* type(I) - type of log entry to create */
/* */
/* Creates a state table log entry using the state structure and type info. */
/* passed in. Log packet/byte counts, source/destination address and other */
/* protocol specific information. */
/* ------------------------------------------------------------------------ */
void ipstate_log(is, type)
struct ipstate *is;
u_int type;
{
#ifdef IPFILTER_LOG
struct ipslog ipsl;
size_t sizes[1];
void *items[1];
int types[1];
/*
* Copy information out of the ipstate_t structure and into the
* structure used for logging.
*/
ipsl.isl_type = type;
ipsl.isl_pkts[0] = is->is_pkts[0] + is->is_icmppkts[0];
ipsl.isl_bytes[0] = is->is_bytes[0];
ipsl.isl_pkts[1] = is->is_pkts[1] + is->is_icmppkts[1];
ipsl.isl_bytes[1] = is->is_bytes[1];
ipsl.isl_pkts[2] = is->is_pkts[2] + is->is_icmppkts[2];
ipsl.isl_bytes[2] = is->is_bytes[2];
ipsl.isl_pkts[3] = is->is_pkts[3] + is->is_icmppkts[3];
ipsl.isl_bytes[3] = is->is_bytes[3];
ipsl.isl_src = is->is_src;
ipsl.isl_dst = is->is_dst;
ipsl.isl_p = is->is_p;
ipsl.isl_v = is->is_v;
ipsl.isl_flags = is->is_flags;
ipsl.isl_tag = is->is_tag;
ipsl.isl_rulen = is->is_rulen;
(void) strncpy(ipsl.isl_group, is->is_group, FR_GROUPLEN);
if (ipsl.isl_p == IPPROTO_TCP || ipsl.isl_p == IPPROTO_UDP) {
ipsl.isl_sport = is->is_sport;
ipsl.isl_dport = is->is_dport;
if (ipsl.isl_p == IPPROTO_TCP) {
ipsl.isl_state[0] = is->is_state[0];
ipsl.isl_state[1] = is->is_state[1];
}
} else if (ipsl.isl_p == IPPROTO_ICMP) {
ipsl.isl_itype = is->is_icmp.ici_type;
} else if (ipsl.isl_p == IPPROTO_ICMPV6) {
ipsl.isl_itype = is->is_icmp.ici_type;
} else {
ipsl.isl_ps.isl_filler[0] = 0;
ipsl.isl_ps.isl_filler[1] = 0;
}
items[0] = &ipsl;
sizes[0] = sizeof(ipsl);
types[0] = 0;
if (ipllog(IPL_LOGSTATE, NULL, items, sizes, types, 1)) {
ATOMIC_INCL(ips_stats.iss_logged);
} else {
ATOMIC_INCL(ips_stats.iss_logfail);
}
#endif
}
#ifdef USE_INET6
/* ------------------------------------------------------------------------ */
/* Function: fr_checkicmp6matchingstate */
/* Returns: ipstate_t* - NULL == no match found, */
/* else pointer to matching state entry */
/* Parameters: fin(I) - pointer to packet information */
/* Locks: NULL == no locks, else Read Lock on ipf_state */
/* */
/* If we've got an ICMPv6 error message, using the information stored in */
/* the ICMPv6 packet, look for a matching state table entry. */
/* ------------------------------------------------------------------------ */
static ipstate_t *fr_checkicmp6matchingstate(fin)
fr_info_t *fin;
{
struct icmp6_hdr *ic6, *oic;
int type, backward, i;
ipstate_t *is, **isp;
u_short sport, dport;
i6addr_t dst, src;
u_short savelen;
icmpinfo_t *ic;
fr_info_t ofin;
tcphdr_t *tcp;
ip6_t *oip6;
u_char pr;
u_int hv;
/*
* 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 ((fin->fin_v != 6) || (fin->fin_plen < ICMP6ERR_MINPKTLEN))
return NULL;
ic6 = fin->fin_dp;
type = ic6->icmp6_type;
/*
* If it's not an error type, then return
*/
if ((type != ICMP6_DST_UNREACH) && (type != ICMP6_PACKET_TOO_BIG) &&
(type != ICMP6_TIME_EXCEEDED) && (type != ICMP6_PARAM_PROB))
return NULL;
oip6 = (ip6_t *)((char *)ic6 + ICMPERR_ICMPHLEN);
if (fin->fin_plen < sizeof(*oip6))
return NULL;
bcopy((char *)fin, (char *)&ofin, sizeof(fin));
ofin.fin_v = 6;
ofin.fin_ifp = fin->fin_ifp;
ofin.fin_out = !fin->fin_out;
ofin.fin_m = NULL; /* if dereferenced, panic XXX */
ofin.fin_mp = NULL; /* if dereferenced, panic XXX */
/*
* We make a fin entry to be able to feed it to
* matchsrcdst. Note that not all fields are necessary
* but this is the cleanest way. Note further we fill
* in fin_mp such that if someone uses it we'll get
* a kernel panic. fr_matchsrcdst does not use this.
*
* watch out here, as ip is in host order and oip6 in network
* order. Any change we make must be undone afterwards.
*/
savelen = oip6->ip6_plen;
oip6->ip6_plen = fin->fin_dlen - ICMPERR_ICMPHLEN;
ofin.fin_flx = FI_NOCKSUM;
ofin.fin_ip = (ip_t *)oip6;
ofin.fin_plen = oip6->ip6_plen;
(void) fr_makefrip(sizeof(*oip6), (ip_t *)oip6, &ofin);
ofin.fin_flx &= ~(FI_BAD|FI_SHORT);
oip6->ip6_plen = savelen;
if (oip6->ip6_nxt == IPPROTO_ICMPV6) {
oic = (struct icmp6_hdr *)(oip6 + 1);
/*
* an ICMP error can only be generated as a result of an
* ICMP query, not as the response on an ICMP error
*
* XXX theoretically ICMP_ECHOREP and the other reply's are
* ICMP query's as well, but adding them here seems strange XXX
*/
if (!(oic->icmp6_type & ICMP6_INFOMSG_MASK))
return NULL;
/*
* perform a lookup of the ICMP packet in the state table
*/
hv = (pr = oip6->ip6_nxt);
src.in6 = oip6->ip6_src;
hv += src.in4.s_addr;
dst.in6 = oip6->ip6_dst;
hv += dst.in4.s_addr;
hv += oic->icmp6_id;
hv += oic->icmp6_seq;
hv = DOUBLE_HASH(hv);
READ_ENTER(&ipf_state);
for (isp = &ips_table[hv]; ((is = *isp) != NULL); ) {
ic = &is->is_icmp;
isp = &is->is_hnext;
if ((is->is_p == pr) &&
!(is->is_pass & FR_NOICMPERR) &&
(oic->icmp6_id == ic->ici_id) &&
(oic->icmp6_seq == ic->ici_seq) &&
(is = fr_matchsrcdst(&ofin, is, &src,
&dst, NULL, FI_ICMPCMP))) {
/*
* in the state table ICMP query's are stored
* with the type of the corresponding ICMP
* response. Correct here
*/
if (((ic->ici_type == ICMP6_ECHO_REPLY) &&
(oic->icmp6_type == ICMP6_ECHO_REQUEST)) ||
(ic->ici_type - 1 == oic->icmp6_type )) {
ips_stats.iss_hits++;
backward = IP6_NEQ(&is->is_dst, &src);
fin->fin_rev = !backward;
i = (backward << 1) + fin->fin_out;
is->is_icmppkts[i]++;
return is;
}
}
}
RWLOCK_EXIT(&ipf_state);
return NULL;
}
hv = (pr = oip6->ip6_nxt);
src.in6 = oip6->ip6_src;
hv += src.i6[0];
hv += src.i6[1];
hv += src.i6[2];
hv += src.i6[3];
dst.in6 = oip6->ip6_dst;
hv += dst.i6[0];
hv += dst.i6[1];
hv += dst.i6[2];
hv += dst.i6[3];
if ((oip6->ip6_nxt == IPPROTO_TCP) || (oip6->ip6_nxt == IPPROTO_UDP)) {
tcp = (tcphdr_t *)(oip6 + 1);
dport = tcp->th_dport;
sport = tcp->th_sport;
hv += dport;
hv += sport;
} else
tcp = NULL;
hv = DOUBLE_HASH(hv);
READ_ENTER(&ipf_state);
for (isp = &ips_table[hv]; ((is = *isp) != NULL); ) {
isp = &is->is_hnext;
/*
* Only allow this icmp though if the
* encapsulated packet was allowed through the
* other way around. Note that the minimal amount
* of info present does not allow for checking against
* tcp internals such as seq and ack numbers.
*/
if ((is->is_p != pr) || (is->is_v != 6) ||
(is->is_pass & FR_NOICMPERR))
continue;
is = fr_matchsrcdst(&ofin, is, &src, &dst, tcp, FI_ICMPCMP);
if (is != NULL) {
ips_stats.iss_hits++;
backward = IP6_NEQ(&is->is_dst, &src);
fin->fin_rev = !backward;
i = (backward << 1) + fin->fin_out;
is->is_icmppkts[i]++;
/*
* we deliberately do not touch the timeouts
* for the accompanying state table entry.
* It remains to be seen if that is correct. XXX
*/
return is;
}
}
RWLOCK_EXIT(&ipf_state);
return NULL;
}
#endif
/* ------------------------------------------------------------------------ */
/* Function: fr_sttab_init */
/* Returns: Nil */
/* Parameters: tqp(I) - pointer to an array of timeout queues for TCP */
/* */
/* Initialise the array of timeout queues for TCP. */
/* ------------------------------------------------------------------------ */
void fr_sttab_init(tqp)
ipftq_t *tqp;
{
int i;
for (i = IPF_TCP_NSTATES - 1; i >= 0; i--) {
tqp[i].ifq_ttl = 0;
tqp[i].ifq_ref = 1;
tqp[i].ifq_head = NULL;
tqp[i].ifq_tail = &tqp[i].ifq_head;
tqp[i].ifq_next = tqp + i + 1;
MUTEX_INIT(&tqp[i].ifq_lock, "ipftq tcp tab");
}
tqp[IPF_TCP_NSTATES - 1].ifq_next = NULL;
tqp[IPF_TCPS_CLOSED].ifq_ttl = fr_tcpclosed;
tqp[IPF_TCPS_LISTEN].ifq_ttl = fr_tcptimeout;
tqp[IPF_TCPS_SYN_SENT].ifq_ttl = fr_tcptimeout;
tqp[IPF_TCPS_SYN_RECEIVED].ifq_ttl = fr_tcptimeout;
tqp[IPF_TCPS_ESTABLISHED].ifq_ttl = fr_tcpidletimeout;
tqp[IPF_TCPS_CLOSE_WAIT].ifq_ttl = fr_tcphalfclosed;
tqp[IPF_TCPS_FIN_WAIT_1].ifq_ttl = fr_tcphalfclosed;
tqp[IPF_TCPS_CLOSING].ifq_ttl = fr_tcptimeout;
tqp[IPF_TCPS_LAST_ACK].ifq_ttl = fr_tcplastack;
tqp[IPF_TCPS_FIN_WAIT_2].ifq_ttl = fr_tcpclosewait;
tqp[IPF_TCPS_TIME_WAIT].ifq_ttl = fr_tcptimeout;
tqp[IPF_TCPS_HALF_ESTAB].ifq_ttl = fr_tcptimeout;
}
/* ------------------------------------------------------------------------ */
/* Function: fr_sttab_destroy */
/* Returns: Nil */
/* Parameters: tqp(I) - pointer to an array of timeout queues for TCP */
/* */
/* Do whatever is necessary to "destroy" each of the entries in the array */
/* of timeout queues for TCP. */
/* ------------------------------------------------------------------------ */
void fr_sttab_destroy(tqp)
ipftq_t *tqp;
{
int i;
for (i = IPF_TCP_NSTATES - 1; i >= 0; i--)
MUTEX_DESTROY(&tqp[i].ifq_lock);
}
/* ------------------------------------------------------------------------ */
/* Function: fr_statederef */
/* Returns: Nil */
/* Parameters: isp(I) - pointer to pointer to state table entry */
/* */
/* Decrement the reference counter for this state table entry and free it */
/* if there are no more things using it. */
/* */
/* When operating in userland (ipftest), we have no timers to clear a state */
/* entry. Therefore, we make a few simple tests before deleting an entry */
/* outright. We compare states on each side looking for a combination of */
/* TIME_WAIT (should really be FIN_WAIT_2?) and LAST_ACK. Then we factor */
/* in packet direction with the interface list to make sure we don't */
/* prematurely delete an entry on a final inbound packet that's we're also */
/* supposed to route elsewhere. */
/* */
/* Internal parameters: */
/* state[0] = state of source (host that initiated connection) */
/* state[1] = state of dest (host that accepted the connection) */
/* */
/* dir == 0 : a packet from source to dest */
/* dir == 1 : a packet from dest to source */
/* ------------------------------------------------------------------------ */
void fr_statederef(fin, isp)
fr_info_t *fin;
ipstate_t **isp;
{
ipstate_t *is = *isp;
#if 0
int nstate, ostate, dir, eol;
eol = 0; /* End-of-the-line flag. */
dir = fin->fin_rev;
ostate = is->is_state[1 - dir];
nstate = is->is_state[dir];
/*
* Determine whether this packet is local or routed. State entries
* with us as the destination will have an interface list of
* int1,-,-,int1. Entries with us as the origin run as -,int1,int1,-.
*/
if ((fin->fin_p == IPPROTO_TCP) && (fin->fin_out == 0)) {
if ((strcmp(is->is_ifname[0], is->is_ifname[3]) == 0) &&
(strcmp(is->is_ifname[1], is->is_ifname[2]) == 0)) {
if ((dir == 0) &&
(strcmp(is->is_ifname[1], "-") == 0) &&
(strcmp(is->is_ifname[0], "-") != 0)) {
eol = 1;
} else if ((dir == 1) &&
(strcmp(is->is_ifname[0], "-") == 0) &&
(strcmp(is->is_ifname[1], "-") != 0)) {
eol = 1;
}
}
}
#endif
fin = fin; /* LINT */
is = *isp;
*isp = NULL;
WRITE_ENTER(&ipf_state);
is->is_ref--;
if (is->is_ref == 0) {
is->is_ref++; /* To counter ref-- in fr_delstate() */
fr_delstate(is, ISL_EXPIRE);
#ifndef _KERNEL
#if 0
} else if (((fin->fin_out == 1) || (eol == 1)) &&
((ostate == IPF_TCPS_LAST_ACK) &&
(nstate == IPF_TCPS_TIME_WAIT))) {
;
#else
} else if ((is->is_sti.tqe_state[0] > IPF_TCPS_ESTABLISHED) ||
(is->is_sti.tqe_state[1] > IPF_TCPS_ESTABLISHED)) {
#endif
fr_delstate(is, ISL_ORPHAN);
#endif
}
RWLOCK_EXIT(&ipf_state);
}
/* ------------------------------------------------------------------------ */
/* Function: fr_setstatequeue */
/* Returns: Nil */
/* Parameters: is(I) - pointer to state structure */
/* rev(I) - forward(0) or reverse(1) direction */
/* Locks: ipf_state (read or write) */
/* */
/* Put the state entry on its default queue entry, using rev as a helped in */
/* determining which queue it should be placed on. */
/* ------------------------------------------------------------------------ */
void fr_setstatequeue(is, rev)
ipstate_t *is;
int rev;
{
ipftq_t *oifq, *nifq;
if ((is->is_sti.tqe_flags & TQE_RULEBASED) != 0)
nifq = is->is_tqehead[rev];
else
nifq = NULL;
if (nifq == NULL) {
switch (is->is_p)
{
#ifdef USE_INET6
case IPPROTO_ICMPV6 :
if (rev == 1)
nifq = &ips_icmpacktq;
else
nifq = &ips_icmptq;
break;
#endif
case IPPROTO_ICMP :
if (rev == 1)
nifq = &ips_icmpacktq;
else
nifq = &ips_icmptq;
break;
case IPPROTO_TCP :
nifq = ips_tqtqb + is->is_state[rev];
break;
case IPPROTO_UDP :
if (rev == 1)
nifq = &ips_udpacktq;
else
nifq = &ips_udptq;
break;
default :
nifq = &ips_iptq;
break;
}
}
oifq = is->is_sti.tqe_ifq;
/*
* If it's currently on a timeout queue, move it from one queue to
* another, else put it on the end of the newly determined queue.
*/
if (oifq != NULL)
fr_movequeue(&is->is_sti, oifq, nifq);
else
fr_queueappend(&is->is_sti, nifq, is);
return;
}
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