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/*
* Copyright (C) 2011 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.
*
* $Id$
*
*/
#define IPF_IPSEC_PROXY
void *ipf_p_ipsec_soft_create __P((ipf_main_softc_t *));
void ipf_p_ipsec_soft_destroy __P((ipf_main_softc_t *, void *));
int ipf_p_ipsec_soft_init __P((ipf_main_softc_t *, void *));
void ipf_p_ipsec_soft_fini __P((ipf_main_softc_t *, void *));
int ipf_p_ipsec_init __P((void));
void ipf_p_ipsec_fini __P((void));
int ipf_p_ipsec_new __P((void *, fr_info_t *, ap_session_t *, nat_t *));
void ipf_p_ipsec_del __P((ipf_main_softc_t *, ap_session_t *));
int ipf_p_ipsec_inout __P((void *, fr_info_t *, ap_session_t *, nat_t *));
int ipf_p_ipsec_match __P((fr_info_t *, ap_session_t *, nat_t *));
typedef struct ipf_ipsec_softc_s {
frentry_t ipsec_fr;
int ipsec_proxy_init;
int ipsec_proxy_ttl;
ipftq_t *ipsec_nat_tqe;
ipftq_t *ipsec_state_tqe;
char ipsec_buffer[1500];
} ipf_ipsec_softc_t;
/*
* IPSec application proxy initialization.
*/
void *
ipf_p_ipsec_soft_create(softc)
ipf_main_softc_t *softc;
{
ipf_ipsec_softc_t *softi;
KMALLOC(softi, ipf_ipsec_softc_t *);
if (softi == NULL)
return NULL;
bzero((char *)softi, sizeof(*softi));
softi->ipsec_fr.fr_ref = 1;
softi->ipsec_fr.fr_flags = FR_OUTQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
MUTEX_INIT(&softi->ipsec_fr.fr_lock, "IPsec proxy rule lock");
softi->ipsec_proxy_init = 1;
softi->ipsec_proxy_ttl = 60;
return softi;
}
int
ipf_p_ipsec_soft_init(softc, arg)
ipf_main_softc_t *softc;
void *arg;
{
ipf_ipsec_softc_t *softi = arg;
softi->ipsec_nat_tqe = ipf_state_add_tq(softc, softi->ipsec_proxy_ttl);
if (softi->ipsec_nat_tqe == NULL)
return -1;
softi->ipsec_state_tqe = ipf_nat_add_tq(softc, softi->ipsec_proxy_ttl);
if (softi->ipsec_state_tqe == NULL) {
if (ipf_deletetimeoutqueue(softi->ipsec_nat_tqe) == 0)
ipf_freetimeoutqueue(softc, softi->ipsec_nat_tqe);
softi->ipsec_nat_tqe = NULL;
return -1;
}
softi->ipsec_nat_tqe->ifq_flags |= IFQF_PROXY;
softi->ipsec_state_tqe->ifq_flags |= IFQF_PROXY;
softi->ipsec_fr.fr_age[0] = softi->ipsec_proxy_ttl;
softi->ipsec_fr.fr_age[1] = softi->ipsec_proxy_ttl;
return 0;
}
void
ipf_p_ipsec_soft_fini(softc, arg)
ipf_main_softc_t *softc;
void *arg;
{
ipf_ipsec_softc_t *softi = arg;
if (arg == NULL)
return;
if (softi->ipsec_nat_tqe != NULL) {
if (ipf_deletetimeoutqueue(softi->ipsec_nat_tqe) == 0)
ipf_freetimeoutqueue(softc, softi->ipsec_nat_tqe);
}
softi->ipsec_nat_tqe = NULL;
if (softi->ipsec_state_tqe != NULL) {
if (ipf_deletetimeoutqueue(softi->ipsec_state_tqe) == 0)
ipf_freetimeoutqueue(softc, softi->ipsec_state_tqe);
}
softi->ipsec_state_tqe = NULL;
}
void
ipf_p_ipsec_soft_destroy(softc, arg)
ipf_main_softc_t *softc;
void *arg;
{
ipf_ipsec_softc_t *softi = arg;
if (softi->ipsec_proxy_init == 1) {
MUTEX_DESTROY(&softi->ipsec_fr.fr_lock);
softi->ipsec_proxy_init = 0;
}
KFREE(softi);
}
/*
* Setup for a new IPSEC proxy.
*/
int
ipf_p_ipsec_new(arg, fin, aps, nat)
void *arg;
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
ipf_ipsec_softc_t *softi = arg;
ipf_main_softc_t *softc = fin->fin_main_soft;
#ifdef USE_MUTEXES
ipf_nat_softc_t *softn = softc->ipf_nat_soft;
#endif
ipsec_pxy_t *ipsec;
ipnat_t *ipn, *np;
fr_info_t fi;
char *ptr;
int p, off, dlen, ttl;
mb_t *m;
ip_t *ip;
off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
bzero(softi->ipsec_buffer, sizeof(softi->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(softi->ipsec_buffer), dlen),
softi->ipsec_buffer);
if (ipf_nat_outlookup(fin, 0, IPPROTO_ESP, nat->nat_nsrcip,
ip->ip_dst) != NULL)
return -1;
np = nat->nat_ptr;
aps->aps_psiz = sizeof(*ipsec) + np->in_namelen;
KMALLOCS(aps->aps_data, ipsec_pxy_t *, aps->aps_psiz);
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(softi->ipsec_nat_tqe->ifq_ttl);
ipn->in_tqehead[0] = ipf_nat_add_tq(softc, ttl);
ipn->in_tqehead[1] = ipf_nat_add_tq(softc, ttl);
ipn->in_ifps[0] = fin->fin_ifp;
ipn->in_apr = NULL;
ipn->in_use = 1;
ipn->in_hits = 1;
ipn->in_snip = ntohl(nat->nat_nsrcaddr);
ipn->in_ippip = 1;
ipn->in_osrcip = nat->nat_osrcip;
ipn->in_osrcmsk = 0xffffffff;
ipn->in_nsrcip = nat->nat_nsrcip;
ipn->in_nsrcmsk = 0xffffffff;
ipn->in_odstip = nat->nat_odstip;
ipn->in_odstmsk = 0xffffffff;
ipn->in_ndstip = nat->nat_ndstip;
ipn->in_ndstmsk = 0xffffffff;
ipn->in_redir = NAT_MAP;
ipn->in_pr[0] = IPPROTO_ESP;
ipn->in_pr[1] = IPPROTO_ESP;
MUTEX_INIT(&ipn->in_lock, "IPSec proxy NAT rule");
ipn->in_namelen = np->in_namelen;
bcopy(np->in_names, ipn->in_ifnames, ipn->in_namelen);
ipn->in_ifnames[0] = np->in_ifnames[0];
ipn->in_ifnames[1] = np->in_ifnames[1];
bcopy((char *)fin, (char *)&fi, sizeof(fi));
fi.fin_fi.fi_p = IPPROTO_ESP;
fi.fin_fr = &softi->ipsec_fr;
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 = softi->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;
MUTEX_ENTER(&softn->ipf_nat_new);
ipsec->ipsc_nat = ipf_nat_add(&fi, ipn, &ipsec->ipsc_nat,
NAT_SLAVE|SI_WILDP, NAT_OUTBOUND);
MUTEX_EXIT(&softn->ipf_nat_new);
if (ipsec->ipsc_nat != NULL) {
(void) ipf_nat_proto(&fi, ipsec->ipsc_nat, 0);
MUTEX_ENTER(&ipsec->ipsc_nat->nat_lock);
ipf_nat_update(&fi, ipsec->ipsc_nat);
MUTEX_EXIT(&ipsec->ipsc_nat->nat_lock);
fi.fin_data[0] = 0;
fi.fin_data[1] = 0;
(void) ipf_state_add(softc, &fi, &ipsec->ipsc_state, SI_WILDP);
}
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
ipf_p_ipsec_inout(arg, fin, aps, nat)
void *arg;
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
ipf_ipsec_softc_t *softi = arg;
ipf_main_softc_t *softc = fin->fin_main_soft;
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_fi.fi_p = IPPROTO_ESP;
fi.fin_fr = &softi->ipsec_fr;
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)
ipf_queueback(softc->ipf_ticks,
&ipsec->ipsc_nat->nat_tqe);
else {
#ifdef USE_MUTEXES
ipf_nat_softc_t *softn = softc->ipf_nat_soft;
#endif
MUTEX_ENTER(&softn->ipf_nat_new);
ipsec->ipsc_nat = ipf_nat_add(&fi, &ipsec->ipsc_rule,
&ipsec->ipsc_nat,
NAT_SLAVE|SI_WILDP,
nat->nat_dir);
MUTEX_EXIT(&softn->ipf_nat_new);
if (ipsec->ipsc_nat != NULL) {
(void) ipf_nat_proto(&fi, ipsec->ipsc_nat, 0);
MUTEX_ENTER(&ipsec->ipsc_nat->nat_lock);
ipf_nat_update(&fi, ipsec->ipsc_nat);
MUTEX_EXIT(&ipsec->ipsc_nat->nat_lock);
}
}
/*
* Update state timeout/create state if missing.
*/
READ_ENTER(&softc->ipf_state);
if (ipsec->ipsc_state != NULL) {
ipf_queueback(softc->ipf_ticks,
&ipsec->ipsc_state->is_sti);
ipsec->ipsc_state->is_die = nat->nat_age;
RWLOCK_EXIT(&softc->ipf_state);
} else {
RWLOCK_EXIT(&softc->ipf_state);
fi.fin_data[0] = 0;
fi.fin_data[1] = 0;
(void) ipf_state_add(softc, &fi, &ipsec->ipsc_state,
SI_WILDP);
}
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
ipf_p_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
ipf_p_ipsec_del(softc, aps)
ipf_main_softc_t *softc;
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(&softc->ipf_state);
if (ipsec->ipsc_state != NULL) {
ipsec->ipsc_state->is_die = softc->ipf_ticks + 1;
ipsec->ipsc_state->is_me = NULL;
ipf_queuefront(&ipsec->ipsc_state->is_sti);
}
RWLOCK_EXIT(&softc->ipf_state);
ipsec->ipsc_state = NULL;
ipsec->ipsc_nat = NULL;
}
}