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/* $FreeBSD$ */
/*
* Copyright (C) 1998-2003 by Darren Reed
*
* See the IPFILTER.LICENCE file for details on licencing.
*
* Id: ip_rcmd_pxy.c,v 1.41.2.4 2005/02/04 10:22:55 darrenr Exp
*
* Simple RCMD transparent proxy for in-kernel use. For use with the NAT
* code.
* $FreeBSD$
*/
#define IPF_RCMD_PROXY
int ippr_rcmd_init __P((void));
void ippr_rcmd_fini __P((void));
int ippr_rcmd_new __P((fr_info_t *, ap_session_t *, nat_t *));
int ippr_rcmd_out __P((fr_info_t *, ap_session_t *, nat_t *));
int ippr_rcmd_in __P((fr_info_t *, ap_session_t *, nat_t *));
u_short ipf_rcmd_atoi __P((char *));
int ippr_rcmd_portmsg __P((fr_info_t *, ap_session_t *, nat_t *));
static frentry_t rcmdfr;
int rcmd_proxy_init = 0;
/*
* RCMD application proxy initialization.
*/
int ippr_rcmd_init()
{
bzero((char *)&rcmdfr, sizeof(rcmdfr));
rcmdfr.fr_ref = 1;
rcmdfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
MUTEX_INIT(&rcmdfr.fr_lock, "RCMD proxy rule lock");
rcmd_proxy_init = 1;
return 0;
}
void ippr_rcmd_fini()
{
if (rcmd_proxy_init == 1) {
MUTEX_DESTROY(&rcmdfr.fr_lock);
rcmd_proxy_init = 0;
}
}
/*
* Setup for a new RCMD proxy.
*/
int ippr_rcmd_new(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
tcphdr_t *tcp = (tcphdr_t *)fin->fin_dp;
fin = fin; /* LINT */
nat = nat; /* LINT */
aps->aps_psiz = sizeof(u_32_t);
KMALLOCS(aps->aps_data, u_32_t *, sizeof(u_32_t));
if (aps->aps_data == NULL) {
#ifdef IP_RCMD_PROXY_DEBUG
printf("ippr_rcmd_new:KMALLOCS(%d) failed\n", sizeof(u_32_t));
#endif
return -1;
}
*(u_32_t *)aps->aps_data = 0;
aps->aps_sport = tcp->th_sport;
aps->aps_dport = tcp->th_dport;
return 0;
}
/*
* ipf_rcmd_atoi - implement a simple version of atoi
*/
u_short ipf_rcmd_atoi(ptr)
char *ptr;
{
register char *s = ptr, c;
register u_short i = 0;
while (((c = *s++) != '\0') && ISDIGIT(c)) {
i *= 10;
i += c - '0';
}
return i;
}
int ippr_rcmd_portmsg(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
tcphdr_t *tcp, tcph, *tcp2 = &tcph;
struct in_addr swip, swip2;
int off, dlen, nflags;
char portbuf[8], *s;
fr_info_t fi;
u_short sp;
nat_t *nat2;
ip_t *ip;
mb_t *m;
tcp = (tcphdr_t *)fin->fin_dp;
if (tcp->th_flags & TH_SYN) {
*(u_32_t *)aps->aps_data = htonl(ntohl(tcp->th_seq) + 1);
return 0;
}
if ((*(u_32_t *)aps->aps_data != 0) &&
(tcp->th_seq != *(u_32_t *)aps->aps_data))
return 0;
m = fin->fin_m;
ip = fin->fin_ip;
off = (char *)tcp - (char *)ip + (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
#ifdef __sgi
dlen = fin->fin_plen - off;
#else
dlen = MSGDSIZE(m) - off;
#endif
if (dlen <= 0)
return 0;
bzero(portbuf, sizeof(portbuf));
COPYDATA(m, off, MIN(sizeof(portbuf), dlen), portbuf);
portbuf[sizeof(portbuf) - 1] = '\0';
s = portbuf;
sp = ipf_rcmd_atoi(s);
if (sp == 0) {
#ifdef IP_RCMD_PROXY_DEBUG
printf("ippr_rcmd_portmsg:sp == 0 dlen %d [%s]\n",
dlen, portbuf);
#endif
return 0;
}
/*
* Add skeleton NAT entry for connection which will come back the
* other way.
*/
bcopy((char *)fin, (char *)&fi, sizeof(fi));
fi.fin_flx |= FI_IGNORE;
fi.fin_data[0] = sp;
fi.fin_data[1] = 0;
if (nat->nat_dir == NAT_OUTBOUND)
nat2 = nat_outlookup(&fi, NAT_SEARCH|IPN_TCP, nat->nat_p,
nat->nat_inip, nat->nat_oip);
else
nat2 = nat_inlookup(&fi, NAT_SEARCH|IPN_TCP, nat->nat_p,
nat->nat_inip, nat->nat_oip);
if (nat2 == NULL) {
int slen;
slen = ip->ip_len;
ip->ip_len = fin->fin_hlen + sizeof(*tcp);
bzero((char *)tcp2, sizeof(*tcp2));
tcp2->th_win = htons(8192);
tcp2->th_sport = htons(sp);
tcp2->th_dport = 0; /* XXX - don't specify remote port */
TCP_OFF_A(tcp2, 5);
tcp2->th_flags = TH_SYN;
fi.fin_dp = (char *)tcp2;
fi.fin_fr = &rcmdfr;
fi.fin_dlen = sizeof(*tcp2);
fi.fin_plen = fi.fin_hlen + sizeof(*tcp2);
fi.fin_flx &= FI_LOWTTL|FI_FRAG|FI_TCPUDP|FI_OPTIONS|FI_IGNORE;
nflags = NAT_SLAVE|IPN_TCP|SI_W_DPORT;
swip = ip->ip_src;
swip2 = ip->ip_dst;
if (nat->nat_dir == NAT_OUTBOUND) {
fi.fin_fi.fi_saddr = nat->nat_inip.s_addr;
ip->ip_src = nat->nat_inip;
} else {
fi.fin_fi.fi_saddr = nat->nat_oip.s_addr;
ip->ip_src = nat->nat_oip;
nflags |= NAT_NOTRULEPORT;
}
nat2 = nat_new(&fi, nat->nat_ptr, NULL, nflags, nat->nat_dir);
if (nat2 != NULL) {
(void) nat_proto(&fi, nat2, IPN_TCP);
nat_update(&fi, nat2, nat2->nat_ptr);
fi.fin_ifp = NULL;
if (nat->nat_dir == NAT_INBOUND) {
fi.fin_fi.fi_daddr = nat->nat_inip.s_addr;
ip->ip_dst = nat->nat_inip;
}
(void) fr_addstate(&fi, &nat2->nat_state, SI_W_DPORT);
if (fi.fin_state != NULL)
fr_statederef(&fi, (ipstate_t **)&fi.fin_state);
}
ip->ip_len = slen;
ip->ip_src = swip;
ip->ip_dst = swip2;
}
return 0;
}
int ippr_rcmd_out(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
if (nat->nat_dir == NAT_OUTBOUND)
return ippr_rcmd_portmsg(fin, aps, nat);
return 0;
}
int ippr_rcmd_in(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
if (nat->nat_dir == NAT_INBOUND)
return ippr_rcmd_portmsg(fin, aps, nat);
return 0;
}
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