/*
* Copyright (C) 2001-2003 by Darren Reed
*
* See the IPFILTER.LICENCE file for details on licencing.
*
* Simple ISAKMP transparent proxy for in-kernel use. For use with the NAT
* code.
*
* $Id: ip_ipsec_pxy.c,v 2.20.2.7 2005/08/20 13:48:22 darrenr Exp $
*
*/
#define IPF_IPSEC_PROXY
int ippr_ipsec_init __P((void));
void ippr_ipsec_fini __P((void));
int ippr_ipsec_new __P((fr_info_t *, ap_session_t *, nat_t *));
void ippr_ipsec_del __P((ap_session_t *));
int ippr_ipsec_inout __P((fr_info_t *, ap_session_t *, nat_t *));
int ippr_ipsec_match __P((fr_info_t *, ap_session_t *, nat_t *));
static frentry_t ipsecfr;
static ipftq_t *ipsecnattqe;
static ipftq_t *ipsecstatetqe;
static char ipsec_buffer[1500];
int ipsec_proxy_init = 0;
int ipsec_proxy_ttl = 60;
/*
* IPSec application proxy initialization.
*/
int ippr_ipsec_init()
{
bzero((char *)&ipsecfr, sizeof(ipsecfr));
ipsecfr.fr_ref = 1;
ipsecfr.fr_flags = FR_OUTQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
MUTEX_INIT(&ipsecfr.fr_lock, "IPsec proxy rule lock");
ipsec_proxy_init = 1;
ipsecnattqe = fr_addtimeoutqueue(&nat_utqe, ipsec_proxy_ttl);
if (ipsecnattqe == NULL)
return -1;
ipsecstatetqe = fr_addtimeoutqueue(&ips_utqe, ipsec_proxy_ttl);
if (ipsecstatetqe == NULL) {
if (fr_deletetimeoutqueue(ipsecnattqe) == 0)
fr_freetimeoutqueue(ipsecnattqe);
ipsecnattqe = NULL;
return -1;
}
ipsecnattqe->ifq_flags |= IFQF_PROXY;
ipsecstatetqe->ifq_flags |= IFQF_PROXY;
ipsecfr.fr_age[0] = ipsec_proxy_ttl;
ipsecfr.fr_age[1] = ipsec_proxy_ttl;
return 0;
}
void ippr_ipsec_fini()
{
if (ipsecnattqe != NULL) {
if (fr_deletetimeoutqueue(ipsecnattqe) == 0)
fr_freetimeoutqueue(ipsecnattqe);
}
ipsecnattqe = NULL;
if (ipsecstatetqe != NULL) {
if (fr_deletetimeoutqueue(ipsecstatetqe) == 0)
fr_freetimeoutqueue(ipsecstatetqe);
}
ipsecstatetqe = NULL;
if (ipsec_proxy_init == 1) {
MUTEX_DESTROY(&ipsecfr.fr_lock);
ipsec_proxy_init = 0;
}
}
/*
* Setup for a new IPSEC proxy.
*/
int ippr_ipsec_new(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
ipsec_pxy_t *ipsec;
fr_info_t fi;
ipnat_t *ipn;
char *ptr;
int p, off, dlen, ttl;
mb_t *m;
ip_t *ip;
off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
bzero(ipsec_buffer, sizeof(ipsec_buffer));
ip = fin->fin_ip;
m = fin->fin_m;
dlen = M_LEN(m) - off;
if (dlen < 16)
return -1;
COPYDATA(m, off, MIN(sizeof(ipsec_buffer), dlen), ipsec_buffer);
if (nat_outlookup(fin, 0, IPPROTO_ESP, nat->nat_inip,
ip->ip_dst) != NULL)
return -1;
aps->aps_psiz = sizeof(*ipsec);
KMALLOCS(aps->aps_data, ipsec_pxy_t *, sizeof(*ipsec));
if (aps->aps_data == NULL)
return -1;
ipsec = aps->aps_data;
bzero((char *)ipsec, sizeof(*ipsec));
/*
* Create NAT rule against which the tunnel/transport mapping is
* created. This is required because the current NAT rule does not
* describe ESP but UDP instead.
*/
ipn = &ipsec->ipsc_rule;
ttl = IPF_TTLVAL(ipsecnattqe->ifq_ttl);
ipn->in_tqehead[0] = fr_addtimeoutqueue(&nat_utqe, ttl);
ipn->in_tqehead[1] = fr_addtimeoutqueue(&nat_utqe, ttl);
ipn->in_ifps[0] = fin->fin_ifp;
ipn->in_apr = NULL;
ipn->in_use = 1;
ipn->in_hits = 1;
ipn->in_nip = ntohl(nat->nat_outip.s_addr);
ipn->in_ippip = 1;
ipn->in_inip = nat->nat_inip.s_addr;
ipn->in_inmsk = 0xffffffff;
ipn->in_outip = fin->fin_saddr;
ipn->in_outmsk = nat->nat_outip.s_addr;
ipn->in_srcip = fin->fin_saddr;
ipn->in_srcmsk = 0xffffffff;
ipn->in_redir = NAT_MAP;
bcopy(nat->nat_ptr->in_ifnames[0], ipn->in_ifnames[0],
sizeof(ipn->in_ifnames[0]));
ipn->in_p = IPPROTO_ESP;
bcopy((char *)fin, (char *)&fi, sizeof(fi));
fi.fin_state = NULL;
fi.fin_nat = NULL;
fi.fin_fi.fi_p = IPPROTO_ESP;
fi.fin_fr = &ipsecfr;
fi.fin_data[0] = 0;
fi.fin_data[1] = 0;
p = ip->ip_p;
ip->ip_p = IPPROTO_ESP;
fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
fi.fin_flx |= FI_IGNORE;
ptr = ipsec_buffer;
bcopy(ptr, (char *)ipsec->ipsc_icookie, sizeof(ipsec_cookie_t));
ptr += sizeof(ipsec_cookie_t);
bcopy(ptr, (char *)ipsec->ipsc_rcookie, sizeof(ipsec_cookie_t));
/*
* The responder cookie should only be non-zero if the initiator
* cookie is non-zero. Therefore, it is safe to assume(!) that the
* cookies are both set after copying if the responder is non-zero.
*/
if ((ipsec->ipsc_rcookie[0]|ipsec->ipsc_rcookie[1]) != 0)
ipsec->ipsc_rckset = 1;
ipsec->ipsc_nat = nat_new(&fi, ipn, &ipsec->ipsc_nat,
NAT_SLAVE|SI_WILDP, NAT_OUTBOUND);
if (ipsec->ipsc_nat != NULL) {
(void) nat_proto(&fi, ipsec->ipsc_nat, 0);
nat_update(&fi, ipsec->ipsc_nat, ipn);
fi.fin_data[0] = 0;
fi.fin_data[1] = 0;
ipsec->ipsc_state = fr_addstate(&fi, &ipsec->ipsc_state,
SI_WILDP);
if (fi.fin_state != NULL)
fr_statederef(&fi, (ipstate_t **)&fi.fin_state);
}
ip->ip_p = p & 0xff;
return 0;
}
/*
* For outgoing IKE packets. refresh timeouts for NAT & state entries, if
* we can. If they have disappeared, recreate them.
*/
int ippr_ipsec_inout(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
ipsec_pxy_t *ipsec;
fr_info_t fi;
ip_t *ip;
int p;
if ((fin->fin_out == 1) && (nat->nat_dir == NAT_INBOUND))
return 0;
if ((fin->fin_out == 0) && (nat->nat_dir == NAT_OUTBOUND))
return 0;
ipsec = aps->aps_data;
if (ipsec != NULL) {
ip = fin->fin_ip;
p = ip->ip_p;
if ((ipsec->ipsc_nat == NULL) || (ipsec->ipsc_state == NULL)) {
bcopy((char *)fin, (char *)&fi, sizeof(fi));
fi.fin_state = NULL;
fi.fin_nat = NULL;
fi.fin_fi.fi_p = IPPROTO_ESP;
fi.fin_fr = &ipsecfr;
fi.fin_data[0] = 0;
fi.fin_data[1] = 0;
ip->ip_p = IPPROTO_ESP;
fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
fi.fin_flx |= FI_IGNORE;
}
/*
* Update NAT timeout/create NAT if missing.
*/
if (ipsec->ipsc_nat != NULL)
fr_queueback(&ipsec->ipsc_nat->nat_tqe);
else {
ipsec->ipsc_nat = nat_new(&fi, &ipsec->ipsc_rule,
&ipsec->ipsc_nat,
NAT_SLAVE|SI_WILDP,
nat->nat_dir);
if (ipsec->ipsc_nat != NULL) {
(void) nat_proto(&fi, ipsec->ipsc_nat, 0);
nat_update(&fi, ipsec->ipsc_nat,
&ipsec->ipsc_rule);
}
}
/*
* Update state timeout/create state if missing.
*/
READ_ENTER(&ipf_state);
if (ipsec->ipsc_state != NULL) {
fr_queueback(&ipsec->ipsc_state->is_sti);
ipsec->ipsc_state->is_die = nat->nat_age;
RWLOCK_EXIT(&ipf_state);
} else {
RWLOCK_EXIT(&ipf_state);
fi.fin_data[0] = 0;
fi.fin_data[1] = 0;
ipsec->ipsc_state = fr_addstate(&fi,
&ipsec->ipsc_state,
SI_WILDP);
if (fi.fin_state != NULL)
fr_statederef(&fi, (ipstate_t **)&fi.fin_state);
}
ip->ip_p = p;
}
return 0;
}
/*
* This extends the NAT matching to be based on the cookies associated with
* a session and found at the front of IKE packets. The cookies are always
* in the same order (not reversed depending on packet flow direction as with
* UDP/TCP port numbers).
*/
int ippr_ipsec_match(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
ipsec_pxy_t *ipsec;
u_32_t cookies[4];
mb_t *m;
int off;
nat = nat; /* LINT */
if ((fin->fin_dlen < sizeof(cookies)) || (fin->fin_flx & FI_FRAG))
return -1;
off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
ipsec = aps->aps_data;
m = fin->fin_m;
COPYDATA(m, off, sizeof(cookies), (char *)cookies);
if ((cookies[0] != ipsec->ipsc_icookie[0]) ||
(cookies[1] != ipsec->ipsc_icookie[1]))
return -1;
if (ipsec->ipsc_rckset == 0) {
if ((cookies[2]|cookies[3]) == 0) {
return 0;
}
ipsec->ipsc_rckset = 1;
ipsec->ipsc_rcookie[0] = cookies[2];
ipsec->ipsc_rcookie[1] = cookies[3];
return 0;
}
if ((cookies[2] != ipsec->ipsc_rcookie[0]) ||
(cookies[3] != ipsec->ipsc_rcookie[1]))
return -1;
return 0;
}
/*
* clean up after ourselves.
*/
void ippr_ipsec_del(aps)
ap_session_t *aps;
{
ipsec_pxy_t *ipsec;
ipsec = aps->aps_data;
if (ipsec != NULL) {
/*
* Don't bother changing any of the NAT structure details,
* *_del() is on a callback from aps_free(), from nat_delete()
*/
READ_ENTER(&ipf_state);
if (ipsec->ipsc_state != NULL) {
ipsec->ipsc_state->is_die = fr_ticks + 1;
ipsec->ipsc_state->is_me = NULL;
fr_queuefront(&ipsec->ipsc_state->is_sti);
}
RWLOCK_EXIT(&ipf_state);
ipsec->ipsc_state = NULL;
ipsec->ipsc_nat = NULL;
}
}
