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/* $OpenBSD: ip_proxy.c,v 1.2 1998/02/17 01:39:06 dgregor Exp $ */
/*
* Copyright (C) 1997 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)
static const char rcsid[] = "@(#)$Id: ip_proxy.c,v 1.2 1998/02/17 01:39:06 dgregor Exp $";
#endif
#if defined(__FreeBSD__) && defined(KERNEL) && !defined(_KERNEL)
# define _KERNEL
#endif
#if !defined(_KERNEL) && !defined(KERNEL)
# include <stdio.h>
# include <string.h>
# include <stdlib.h>
#endif
#include <sys/errno.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/fcntl.h>
#include <sys/uio.h>
#ifndef linux
# include <sys/protosw.h>
#endif
#include <sys/socket.h>
#if defined(_KERNEL)
# if !defined(linux)
# include <sys/systm.h>
# else
# include <linux/string.h>
# endif
#endif
#if !defined(__SVR4) && !defined(__svr4__)
# ifndef linux
# include <sys/mbuf.h>
# endif
#else
# include <sys/byteorder.h>
# include <sys/dditypes.h>
# include <sys/stream.h>
# include <sys/kmem.h>
#endif
#if __FreeBSD__ > 2
# include <sys/queue.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>
#ifndef linux
# include <netinet/ip_var.h>
#endif
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <netinet/ip_icmp.h>
#include "ip_fil_compat.h"
#include <netinet/tcpip.h>
#include "ip_fil.h"
#include "ip_proxy.h"
#include "ip_nat.h"
#include "ip_state.h"
#ifndef MIN
#define MIN(a,b) (((a)<(b))?(a):(b))
#endif
static ap_session_t *ap_find __P((ip_t *, tcphdr_t *));
static ap_session_t *ap_new_session __P((aproxy_t *, ip_t *, tcphdr_t *,
fr_info_t *, nat_t *));
#define AP_SESS_SIZE 53
#if defined(_KERNEL) && !defined(linux)
#include "netinet/ip_ftp_pxy.c"
#endif
ap_session_t *ap_sess_tab[AP_SESS_SIZE];
aproxy_t ap_proxies[] = {
#ifdef IPF_FTP_PROXY
{ "ftp", (char)IPPROTO_TCP, 0, 0, ippr_ftp_init, ippr_ftp_in, ippr_ftp_out },
#endif
{ "", '\0', 0, 0, NULL, NULL }
};
int ap_ok(ip, tcp, nat)
ip_t *ip;
tcphdr_t *tcp;
ipnat_t *nat;
{
aproxy_t *apr = nat->in_apr;
u_short dport = nat->in_dport;
if (!apr || (apr && (apr->apr_flags & APR_DELETE)) ||
(ip->ip_p != apr->apr_p))
return 0;
if ((tcp && (tcp->th_dport != dport)) || (!tcp && dport))
return 0;
return 1;
}
static ap_session_t *ap_find(ip, tcp)
ip_t *ip;
tcphdr_t *tcp;
{
struct in_addr src, dst;
register u_long hv;
register u_short sp, dp;
register ap_session_t *aps;
register u_char p = ip->ip_p;
src = ip->ip_src, dst = ip->ip_dst;
sp = dp = 0; /* XXX gcc -Wunitialized */
hv = ip->ip_src.s_addr ^ ip->ip_dst.s_addr;
hv *= 651733;
if (tcp) {
sp = tcp->th_sport;
dp = tcp->th_dport;
hv ^= (sp + dp);
hv *= 5;
}
hv %= AP_SESS_SIZE;
for (aps = ap_sess_tab[hv]; aps; aps = aps->aps_next)
if ((aps->aps_p == p) &&
IPPAIR(aps->aps_src, aps->aps_dst, src, dst)) {
if (tcp) {
if (PAIRS(aps->aps_sport, aps->aps_dport,
sp, dp))
break;
} else
break;
}
return aps;
}
/*
* Allocate a new application proxy structure and fill it in with the
* relevant details. call the init function once complete, prior to
* returning.
*/
static ap_session_t *ap_new_session(apr, ip, tcp, fin, nat)
aproxy_t *apr;
ip_t *ip;
tcphdr_t *tcp;
fr_info_t *fin;
nat_t *nat;
{
register ap_session_t *aps;
u_short dport;
u_long hv;
if (!apr || (apr && (apr->apr_flags & APR_DELETE)) ||
(ip->ip_p != apr->apr_p))
return NULL;
dport = nat->nat_ptr->in_dport;
if ((tcp && (tcp->th_dport != dport)) || (!tcp && dport))
return NULL;
hv = ip->ip_src.s_addr ^ ip->ip_dst.s_addr;
hv *= 651733;
if (tcp) {
hv ^= (tcp->th_sport + tcp->th_dport);
hv *= 5;
}
hv %= AP_SESS_SIZE;
KMALLOC(aps, ap_session_t *, sizeof(*aps));
if (!aps)
return NULL;
bzero((char *)aps, sizeof(*aps));
aps->aps_apr = apr;
aps->aps_src = ip->ip_src;
aps->aps_dst = ip->ip_dst;
aps->aps_p = ip->ip_p;
aps->aps_tout = 1200; /* XXX */
if (tcp) {
aps->aps_sport = tcp->th_sport;
aps->aps_dport = tcp->th_dport;
}
aps->aps_data = NULL;
aps->aps_psiz = 0;
aps->aps_next = ap_sess_tab[hv];
ap_sess_tab[hv] = aps;
(void) (*apr->apr_init)(fin, ip, tcp, aps, nat);
return aps;
}
/*
* check to see if a packet should be passed through an active proxy routine
* if one has been setup for it.
*/
int ap_check(ip, tcp, fin, nat)
ip_t *ip;
tcphdr_t *tcp;
fr_info_t *fin;
nat_t *nat;
{
ap_session_t *aps;
aproxy_t *apr;
int err;
if (!(fin->fin_fi.fi_fl & FI_TCPUDP))
tcp = NULL;
if ((aps = ap_find(ip, tcp)) ||
(aps = ap_new_session(nat->nat_ptr->in_apr, ip, tcp, fin, nat))) {
if (ip->ip_p == IPPROTO_TCP) {
/*
* verify that the checksum is correct. If not, then
* don't do anything with this packet.
*/
if (tcp->th_sum != fr_tcpsum(*(mb_t **)fin->fin_mp,
ip, tcp, ip->ip_len)) {
frstats[fin->fin_out].fr_tcpbad++;
return -1;
}
fr_tcp_age(&aps->aps_tout, aps->aps_state, ip, fin,
tcp->th_sport == aps->aps_sport);
}
apr = aps->aps_apr;
err = 0;
if (fin->fin_out) {
if (apr->apr_outpkt)
err = (*apr->apr_outpkt)(fin, ip, tcp,
aps, nat);
} else {
if (apr->apr_inpkt)
err = (*apr->apr_inpkt)(fin, ip, tcp,
aps, nat);
}
if (err == 2) {
tcp->th_sum = fr_tcpsum(*(mb_t **)fin->fin_mp, ip,
tcp, ip->ip_len);
err = 0;
}
return err;
}
return -1;
}
aproxy_t *ap_match(pr, name)
u_char pr;
char *name;
{
aproxy_t *ap;
for (ap = ap_proxies; ap->apr_p; ap++)
if ((ap->apr_p == pr) &&
!strncmp(name, ap->apr_label, sizeof(ap->apr_label))) {
ap->apr_ref++;
return ap;
}
return NULL;
}
void ap_free(ap)
aproxy_t *ap;
{
ap->apr_ref--;
}
void aps_free(aps)
ap_session_t *aps;
{
if (aps->aps_data && aps->aps_psiz)
KFREES(aps->aps_data, aps->aps_psiz);
KFREE(aps);
}
void ap_unload()
{
ap_session_t *aps;
int i;
for (i = 0; i < AP_SESS_SIZE; i++)
while ((aps = ap_sess_tab[i])) {
ap_sess_tab[i] = aps->aps_next;
aps_free(aps);
}
}
void ap_expire()
{
ap_session_t *aps, **apsp;
int i;
for (i = 0; i < AP_SESS_SIZE; i++)
for (apsp = &ap_sess_tab[i]; (aps = *apsp); ) {
aps->aps_tout--;
if (!aps->aps_tout) {
ap_sess_tab[i] = aps->aps_next;
aps_free(aps);
*apsp = aps->aps_next;
} else
apsp = &aps->aps_next;
}
}
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