553 lines
12 KiB
C
553 lines
12 KiB
C
/* $NetBSD: ip_state.c,v 1.3 1997/03/29 00:55:04 thorpej Exp $ */
|
|
|
|
/*
|
|
* (C)opyright 1995 by Darren Reed.
|
|
*
|
|
* Redistribution and use in source and binary forms are permitted
|
|
* provided that this notice is preserved and due credit is given
|
|
* to the original author and the contributors.
|
|
*/
|
|
#if !defined(lint) && defined(LIBC_SCCS)
|
|
static char sccsid[] = "@(#)ip_state.c 1.8 6/5/96 (C) 1993-1995 Darren Reed";
|
|
static char rcsid[] = "$Id: ip_state.c,v 1.3 1997/03/29 00:55:04 thorpej Exp $";
|
|
#endif
|
|
|
|
#if !defined(_KERNEL) && !defined(KERNEL)
|
|
# include <stdlib.h>
|
|
# include <string.h>
|
|
#endif
|
|
#include <sys/errno.h>
|
|
#include <sys/types.h>
|
|
#include <sys/param.h>
|
|
#include <sys/file.h>
|
|
#include <sys/ioctl.h>
|
|
#include <sys/uio.h>
|
|
#include <sys/protosw.h>
|
|
#include <sys/socket.h>
|
|
#ifdef _KERNEL
|
|
# include <sys/systm.h>
|
|
#endif
|
|
#if !defined(__SVR4) && !defined(__svr4__)
|
|
# include <sys/mbuf.h>
|
|
#else
|
|
# include <sys/byteorder.h>
|
|
# include <sys/dditypes.h>
|
|
# 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/ip_var.h>
|
|
#include <netinet/tcp.h>
|
|
#include <netinet/tcp_fsm.h>
|
|
#include <netinet/udp.h>
|
|
#include <netinet/tcpip.h>
|
|
#include <netinet/ip_icmp.h>
|
|
#include <netinet/ip_compat.h>
|
|
#include <netinet/ip_fil.h>
|
|
#include <netinet/ip_state.h>
|
|
#ifndef MIN
|
|
#define MIN(a,b) (((a)<(b))?(a):(b))
|
|
#endif
|
|
|
|
#define TCP_CLOSE (TH_FIN|TH_RST)
|
|
|
|
ipstate_t *ips_table[IPSTATE_SIZE];
|
|
int ips_num = 0;
|
|
ips_stat_t ips_stats;
|
|
#if SOLARIS
|
|
extern kmutex_t ipf_state;
|
|
# if !defined(_KERNEL)
|
|
#define bcopy(a,b,c) memmove(b,a,c)
|
|
# endif
|
|
#endif
|
|
|
|
|
|
#define FIVE_DAYS (2 * 5 * 86400) /* 5 days: half closed session */
|
|
|
|
u_long fr_tcpidletimeout = FIVE_DAYS,
|
|
fr_tcpclosewait = 60,
|
|
fr_tcplastack = 20,
|
|
fr_tcptimeout = 120,
|
|
fr_tcpclosed = 1,
|
|
fr_udptimeout = 120,
|
|
fr_icmptimeout = 120;
|
|
|
|
|
|
ips_stat_t *fr_statetstats()
|
|
{
|
|
ips_stats.iss_active = ips_num;
|
|
ips_stats.iss_table = ips_table;
|
|
return &ips_stats;
|
|
}
|
|
|
|
|
|
#define PAIRS(s1,d1,s2,d2) ((((s1) == (s2)) && ((d1) == (d2))) ||\
|
|
(((s1) == (d2)) && ((d1) == (s2))))
|
|
#define IPPAIR(s1,d1,s2,d2) PAIRS((s1).s_addr, (d1).s_addr, \
|
|
(s2).s_addr, (d2).s_addr)
|
|
|
|
/*
|
|
* Create a new ipstate structure and hang it off the hash table.
|
|
*/
|
|
int fr_addstate(ip, fin, pass)
|
|
ip_t *ip;
|
|
fr_info_t *fin;
|
|
u_int pass;
|
|
{
|
|
ipstate_t ips;
|
|
register ipstate_t *is = &ips;
|
|
register u_int hv;
|
|
|
|
if ((ip->ip_off & 0x1fff) || (fin->fin_fi.fi_fl & FI_SHORT))
|
|
return -1;
|
|
if (ips_num == IPSTATE_MAX) {
|
|
ips_stats.iss_max++;
|
|
return -1;
|
|
}
|
|
ips.is_age = 1;
|
|
ips.is_state[0] = 0;
|
|
ips.is_state[1] = 0;
|
|
/*
|
|
* Copy and calculate...
|
|
*/
|
|
hv = (is->is_p = ip->ip_p);
|
|
hv += (is->is_src.s_addr = ip->ip_src.s_addr);
|
|
hv += (is->is_dst.s_addr = ip->ip_dst.s_addr);
|
|
|
|
switch (ip->ip_p)
|
|
{
|
|
case IPPROTO_ICMP :
|
|
{
|
|
struct icmp *ic = (struct icmp *)fin->fin_dp;
|
|
|
|
switch (ic->icmp_type)
|
|
{
|
|
case ICMP_ECHO :
|
|
is->is_icmp.ics_type = 0;
|
|
hv += (is->is_icmp.ics_id = ic->icmp_id);
|
|
hv += (is->is_icmp.ics_seq = ic->icmp_seq);
|
|
break;
|
|
case ICMP_TSTAMP :
|
|
case ICMP_IREQ :
|
|
case ICMP_MASKREQ :
|
|
is->is_icmp.ics_type = ic->icmp_type + 1;
|
|
break;
|
|
default :
|
|
return -1;
|
|
}
|
|
ips_stats.iss_icmp++;
|
|
is->is_age = fr_icmptimeout;
|
|
break;
|
|
}
|
|
case IPPROTO_TCP :
|
|
{
|
|
register tcphdr_t *tcp = (tcphdr_t *)fin->fin_dp;
|
|
|
|
/*
|
|
* The endian of the ports doesn't matter, but the ack and
|
|
* sequence numbers do as we do mathematics on them later.
|
|
*/
|
|
hv += (is->is_dport = tcp->th_dport);
|
|
hv += (is->is_sport = tcp->th_sport);
|
|
is->is_seq = ntohl(tcp->th_seq);
|
|
is->is_ack = ntohl(tcp->th_ack);
|
|
is->is_swin = ntohs(tcp->th_win);
|
|
is->is_dwin = is->is_swin; /* start them the same */
|
|
ips_stats.iss_tcp++;
|
|
/*
|
|
* If we're creating state for a starting connectoin, start the
|
|
* timer on it as we'll never see an error if it fails to
|
|
* connect.
|
|
*/
|
|
if ((tcp->th_flags & (TH_SYN|TH_ACK)) == TH_SYN)
|
|
is->is_ack = 0; /* Trumpet WinSock 'ism */
|
|
fr_tcp_age(&is->is_age, is->is_state, ip, fin,
|
|
tcp->th_sport == is->is_sport);
|
|
break;
|
|
}
|
|
case IPPROTO_UDP :
|
|
{
|
|
register tcphdr_t *tcp = (tcphdr_t *)fin->fin_dp;
|
|
|
|
hv += (is->is_dport = tcp->th_dport);
|
|
hv += (is->is_sport = tcp->th_sport);
|
|
ips_stats.iss_udp++;
|
|
is->is_age = fr_udptimeout;
|
|
break;
|
|
}
|
|
default :
|
|
return -1;
|
|
}
|
|
|
|
KMALLOC(is, ipstate_t *, sizeof(*is));
|
|
if (is == NULL) {
|
|
ips_stats.iss_nomem++;
|
|
return -1;
|
|
}
|
|
bcopy((char *)&ips, (char *)is, sizeof(*is));
|
|
hv %= IPSTATE_SIZE;
|
|
MUTEX_ENTER(&ipf_state);
|
|
is->is_next = ips_table[hv];
|
|
ips_table[hv] = is;
|
|
is->is_pass = pass;
|
|
is->is_pkts = 1;
|
|
is->is_bytes = ip->ip_len;
|
|
if (pass & FR_LOGFIRST)
|
|
is->is_pass &= ~(FR_LOGFIRST|FR_LOG);
|
|
ips_num++;
|
|
MUTEX_EXIT(&ipf_state);
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
int fr_tcpstate(is, fin, ip, tcp, sport)
|
|
register ipstate_t *is;
|
|
fr_info_t *fin;
|
|
ip_t *ip;
|
|
tcphdr_t *tcp;
|
|
u_short sport;
|
|
{
|
|
register int seqskew, ackskew;
|
|
register u_short swin, dwin;
|
|
register tcp_seq seq, ack;
|
|
int source;
|
|
|
|
/*
|
|
* Find difference between last checked packet and this packet.
|
|
*/
|
|
seq = ntohl(tcp->th_seq);
|
|
ack = ntohl(tcp->th_ack);
|
|
if (sport == is->is_sport) {
|
|
seqskew = seq - is->is_seq;
|
|
ackskew = ack - is->is_ack;
|
|
} else {
|
|
seqskew = ack - is->is_seq;
|
|
if (!is->is_ack)
|
|
/*
|
|
* Must be a SYN-ACK in reply to a SYN.
|
|
*/
|
|
is->is_ack = seq;
|
|
ackskew = seq - is->is_ack;
|
|
}
|
|
|
|
/*
|
|
* Make skew values absolute
|
|
*/
|
|
if (seqskew < 0)
|
|
seqskew = -seqskew;
|
|
if (ackskew < 0)
|
|
ackskew = -ackskew;
|
|
|
|
/*
|
|
* If the difference in sequence and ack numbers is within the
|
|
* window size of the connection, store these values and match
|
|
* the packet.
|
|
*/
|
|
if ((source = (sport == is->is_sport))) {
|
|
swin = is->is_swin;
|
|
dwin = is->is_dwin;
|
|
} else {
|
|
dwin = is->is_swin;
|
|
swin = is->is_dwin;
|
|
}
|
|
|
|
if ((seqskew <= swin) && (ackskew <= dwin)) {
|
|
if (source) {
|
|
is->is_seq = seq;
|
|
is->is_ack = ack;
|
|
is->is_swin = ntohs(tcp->th_win);
|
|
} else {
|
|
is->is_seq = ack;
|
|
is->is_ack = seq;
|
|
is->is_dwin = ntohs(tcp->th_win);
|
|
}
|
|
ips_stats.iss_hits++;
|
|
/*
|
|
* Nearing end of connection, start timeout.
|
|
*/
|
|
fr_tcp_age(&is->is_age, is->is_state, ip, fin,
|
|
tcp->th_sport == is->is_sport);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* Check if a packet has a registered state.
|
|
*/
|
|
int fr_checkstate(ip, fin)
|
|
ip_t *ip;
|
|
fr_info_t *fin;
|
|
{
|
|
register struct in_addr dst, src;
|
|
register ipstate_t *is, **isp;
|
|
register u_char pr;
|
|
struct icmp *ic;
|
|
tcphdr_t *tcp;
|
|
u_int hv, hlen, pass;
|
|
|
|
if ((ip->ip_off & 0x1fff) || (fin->fin_fi.fi_fl & FI_SHORT))
|
|
return 0;
|
|
|
|
hlen = fin->fin_hlen;
|
|
tcp = (tcphdr_t *)((char *)ip + hlen);
|
|
ic = (struct icmp *)tcp;
|
|
hv = (pr = ip->ip_p);
|
|
hv += (src.s_addr = ip->ip_src.s_addr);
|
|
hv += (dst.s_addr = ip->ip_dst.s_addr);
|
|
|
|
/*
|
|
* Search the hash table for matching packet header info.
|
|
*/
|
|
switch (ip->ip_p)
|
|
{
|
|
case IPPROTO_ICMP :
|
|
hv += ic->icmp_id;
|
|
hv += ic->icmp_seq;
|
|
hv %= IPSTATE_SIZE;
|
|
MUTEX_ENTER(&ipf_state);
|
|
for (isp = &ips_table[hv]; (is = *isp); isp = &is->is_next)
|
|
if ((is->is_p == pr) &&
|
|
(ic->icmp_id == is->is_icmp.ics_id) &&
|
|
(ic->icmp_seq == is->is_icmp.ics_seq) &&
|
|
IPPAIR(src, dst, is->is_src, is->is_dst)) {
|
|
/*
|
|
* If we have type 0 stored, allow any icmp
|
|
* replies through.
|
|
*/
|
|
if (is->is_icmp.ics_type &&
|
|
is->is_icmp.ics_type != ic->icmp_type)
|
|
continue;
|
|
is->is_age = fr_icmptimeout;
|
|
is->is_pkts++;
|
|
is->is_bytes += ip->ip_len;
|
|
ips_stats.iss_hits++;
|
|
MUTEX_EXIT(&ipf_state);
|
|
return is->is_pass;
|
|
}
|
|
MUTEX_EXIT(&ipf_state);
|
|
break;
|
|
case IPPROTO_TCP :
|
|
{
|
|
register u_short dport = tcp->th_dport, sport = tcp->th_sport;
|
|
|
|
hv += dport;
|
|
hv += sport;
|
|
hv %= IPSTATE_SIZE;
|
|
MUTEX_ENTER(&ipf_state);
|
|
for (isp = &ips_table[hv]; (is = *isp); isp = &is->is_next) {
|
|
if ((is->is_p == pr) &&
|
|
PAIRS(sport, dport, is->is_sport, is->is_dport) &&
|
|
IPPAIR(src, dst, is->is_src, is->is_dst))
|
|
if (fr_tcpstate(is, fin, ip, tcp, sport)) {
|
|
/*
|
|
* XXX This was "#ifdef _KERNEL", but that seemed clearly wrong.
|
|
* XXX --thorpej
|
|
*/
|
|
#ifndef _KERNEL
|
|
MUTEX_EXIT(&ipf_state);
|
|
/*
|
|
* XXX This is never initialized!
|
|
* XXX --thorpej
|
|
*/
|
|
return pass;
|
|
#else
|
|
int pass = is->is_pass;
|
|
|
|
if (tcp->th_flags & TCP_CLOSE) {
|
|
*isp = is->is_next;
|
|
isp = &ips_table[hv];
|
|
KFREE(is);
|
|
}
|
|
return pass;
|
|
#endif
|
|
}
|
|
}
|
|
MUTEX_EXIT(&ipf_state);
|
|
break;
|
|
}
|
|
case IPPROTO_UDP :
|
|
{
|
|
register u_short dport = tcp->th_dport, sport = tcp->th_sport;
|
|
|
|
hv += dport;
|
|
hv += sport;
|
|
hv %= IPSTATE_SIZE;
|
|
/*
|
|
* Nothing else to match on but ports. and IP#'s
|
|
*/
|
|
MUTEX_ENTER(&ipf_state);
|
|
for (is = ips_table[hv]; is; is = is->is_next)
|
|
if ((is->is_p == pr) &&
|
|
PAIRS(sport, dport, is->is_sport, is->is_dport) &&
|
|
IPPAIR(src, dst, is->is_src, is->is_dst)) {
|
|
ips_stats.iss_hits++;
|
|
is->is_pkts++;
|
|
is->is_bytes += ip->ip_len;
|
|
is->is_age = fr_udptimeout;
|
|
pass = is->is_pass;
|
|
MUTEX_EXIT(&ipf_state);
|
|
return pass;
|
|
}
|
|
MUTEX_EXIT(&ipf_state);
|
|
break;
|
|
}
|
|
default :
|
|
break;
|
|
}
|
|
ips_stats.iss_miss++;
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* Free memory in use by all state info. kept.
|
|
*/
|
|
void fr_stateunload()
|
|
{
|
|
register int i;
|
|
register ipstate_t *is, **isp;
|
|
int s;
|
|
|
|
MUTEX_ENTER(&ipf_state);
|
|
SPLNET(s);
|
|
for (i = 0; i < IPSTATE_SIZE; i++)
|
|
for (isp = &ips_table[i]; (is = *isp); ) {
|
|
*isp = is->is_next;
|
|
KFREE(is);
|
|
}
|
|
SPLX(s);
|
|
MUTEX_EXIT(&ipf_state);
|
|
}
|
|
|
|
|
|
/*
|
|
* Slowly expire held state for thingslike UDP and ICMP. Timeouts are set
|
|
* in expectation of this being called twice per second.
|
|
*/
|
|
void fr_timeoutstate()
|
|
{
|
|
register int i;
|
|
register ipstate_t *is, **isp;
|
|
int s;
|
|
|
|
MUTEX_ENTER(&ipf_state);
|
|
SPLNET(s);
|
|
for (i = 0; i < IPSTATE_SIZE; i++)
|
|
for (isp = &ips_table[i]; (is = *isp); )
|
|
if (is->is_age && !--is->is_age) {
|
|
*isp = is->is_next;
|
|
if (is->is_p == IPPROTO_TCP)
|
|
ips_stats.iss_fin++;
|
|
else
|
|
ips_stats.iss_expire++;
|
|
KFREE(is);
|
|
ips_num--;
|
|
} else
|
|
isp = &is->is_next;
|
|
SPLX(s);
|
|
MUTEX_EXIT(&ipf_state);
|
|
}
|
|
|
|
|
|
/*
|
|
* Original idea freom Pradeep Krishnan for use primarily with NAT code.
|
|
* (pkrishna@netcom.com)
|
|
*/
|
|
void fr_tcp_age(age, state, ip, fin, dir)
|
|
u_long *age;
|
|
u_char *state;
|
|
ip_t *ip;
|
|
fr_info_t *fin;
|
|
int dir;
|
|
{
|
|
tcphdr_t *tcp = (tcphdr_t *)fin->fin_dp;
|
|
u_char flags = tcp->th_flags;
|
|
int dlen, ostate;
|
|
|
|
ostate = state[1 - dir];
|
|
|
|
dlen = ip->ip_len - fin->fin_hlen - (tcp->th_off << 2);
|
|
|
|
if (flags & TH_RST) {
|
|
if (!(tcp->th_flags & TH_PUSH) && !dlen) {
|
|
*age = fr_tcpclosed;
|
|
state[dir] = TCPS_CLOSED;
|
|
} else {
|
|
*age = fr_tcpclosewait;
|
|
state[dir] = TCPS_CLOSE_WAIT;
|
|
}
|
|
return;
|
|
}
|
|
|
|
*age = fr_tcptimeout; /* 1 min */
|
|
|
|
switch(state[dir])
|
|
{
|
|
case TCPS_FIN_WAIT_2:
|
|
case TCPS_CLOSED:
|
|
if ((flags & TH_OPENING) == TH_OPENING)
|
|
state[dir] = TCPS_SYN_RECEIVED;
|
|
else if (flags & TH_SYN)
|
|
state[dir] = TCPS_SYN_SENT;
|
|
break;
|
|
case TCPS_SYN_RECEIVED:
|
|
if ((flags & (TH_FIN|TH_ACK)) == TH_ACK) {
|
|
state[dir] = TCPS_ESTABLISHED;
|
|
*age = fr_tcpidletimeout;
|
|
}
|
|
break;
|
|
case TCPS_SYN_SENT:
|
|
if ((flags & (TH_FIN|TH_ACK)) == TH_ACK) {
|
|
state[dir] = TCPS_ESTABLISHED;
|
|
*age = fr_tcpidletimeout;
|
|
}
|
|
break;
|
|
case TCPS_ESTABLISHED:
|
|
if (flags & TH_FIN) {
|
|
state[dir] = TCPS_CLOSE_WAIT;
|
|
if (!(flags & TH_PUSH) && !dlen &&
|
|
ostate > TCPS_ESTABLISHED)
|
|
*age = fr_tcplastack;
|
|
else
|
|
*age = fr_tcpclosewait;
|
|
} else
|
|
*age = fr_tcpidletimeout;
|
|
break;
|
|
case TCPS_CLOSE_WAIT:
|
|
if ((flags & TH_FIN) && !(flags & TH_PUSH) && !dlen &&
|
|
ostate > TCPS_ESTABLISHED) {
|
|
*age = fr_tcplastack;
|
|
state[dir] = TCPS_LAST_ACK;
|
|
} else
|
|
*age = fr_tcpclosewait;
|
|
break;
|
|
case TCPS_LAST_ACK:
|
|
if (flags & TH_ACK) {
|
|
state[dir] = TCPS_FIN_WAIT_2;
|
|
if (!(flags & TH_PUSH) && !dlen &&
|
|
ostate > TCPS_ESTABLISHED)
|
|
*age = fr_tcplastack;
|
|
else {
|
|
*age = fr_tcpclosewait;
|
|
state[dir] = TCPS_CLOSE_WAIT;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
}
|