NetBSD/sys/netinet/ip_pptp_pxy.c

272 lines
5.7 KiB
C

/* $NetBSD: ip_pptp_pxy.c,v 1.1.1.2 2004/07/23 05:35:04 martti Exp $ */
/*
* Copyright (C) 2002-2003 by Darren Reed
*
* Simple PPTP transparent proxy for in-kernel use. For use with the NAT
* code.
*
* Id: ip_pptp_pxy.c,v 2.10.2.5 2004/06/07 14:20:05 darrenr Exp
*
*/
#define IPF_PPTP_PROXY
typedef struct pptp_pxy {
ipnat_t pptp_rule;
nat_t *pptp_nat;
ipstate_t *pptp_state;
int pptp_seencookie;
u_32_t pptp_cookie;
} pptp_pxy_t;
int ippr_pptp_init __P((void));
void ippr_pptp_fini __P((void));
int ippr_pptp_new __P((fr_info_t *, ap_session_t *, nat_t *));
void ippr_pptp_del __P((ap_session_t *));
int ippr_pptp_inout __P((fr_info_t *, ap_session_t *, nat_t *));
int ippr_pptp_match __P((fr_info_t *, ap_session_t *, nat_t *));
static frentry_t pptpfr;
int pptp_proxy_init = 0;
/*
* PPTP application proxy initialization.
*/
int ippr_pptp_init()
{
bzero((char *)&pptpfr, sizeof(pptpfr));
pptpfr.fr_ref = 1;
pptpfr.fr_flags = FR_OUTQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
MUTEX_INIT(&pptpfr.fr_lock, "PPTP proxy rule lock");
pptp_proxy_init = 1;
return 0;
}
void ippr_pptp_fini()
{
if (pptp_proxy_init == 1) {
MUTEX_DESTROY(&pptpfr.fr_lock);
pptp_proxy_init = 0;
}
}
/*
* Setup for a new PPTP proxy.
*/
int ippr_pptp_new(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
pptp_pxy_t *pptp;
fr_info_t fi;
ipnat_t *ipn;
nat_t *nat2;
int p, off;
ip_t *ip;
ip = fin->fin_ip;
off = fin->fin_hlen + sizeof(udphdr_t);
if (nat_outlookup(fin, 0, IPPROTO_GRE, nat->nat_inip,
ip->ip_dst) != NULL)
return -1;
aps->aps_psiz = sizeof(*pptp);
KMALLOCS(aps->aps_data, pptp_pxy_t *, sizeof(*pptp));
if (aps->aps_data == NULL)
return -1;
ip = fin->fin_ip;
pptp = aps->aps_data;
bzero((char *)pptp, sizeof(*pptp));
/*
* Create NAT rule against which the tunnel/transport mapping is
* created. This is required because the current NAT rule does not
* describe GRE but TCP instead.
*/
ipn = &pptp->pptp_rule;
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_GRE;
bcopy((char *)fin, (char *)&fi, sizeof(fi));
fi.fin_fi.fi_p = IPPROTO_GRE;
fi.fin_fr = &pptpfr;
fi.fin_data[0] = 0;
fi.fin_data[1] = 0;
p = ip->ip_p;
ip->ip_p = IPPROTO_GRE;
fi.fin_flx &= ~FI_TCPUDP;
fi.fin_flx |= FI_IGNORE;
nat2 = nat_new(&fi, ipn, &pptp->pptp_nat, 0, NAT_OUTBOUND);
pptp->pptp_nat = nat2;
if (nat2 != NULL) {
(void) nat_proto(&fi, nat2, 0);
nat_update(&fi, nat2, nat2->nat_ptr);
fi.fin_data[0] = 0;
fi.fin_data[1] = 0;
pptp->pptp_state = fr_addstate(&fi, &pptp->pptp_state, 0);
}
ip->ip_p = p;
return 0;
}
/*
* For outgoing PPTP packets. refresh timeouts for NAT & state entries, if
* we can. If they have disappeared, recreate them.
*/
int ippr_pptp_inout(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
pptp_pxy_t *pptp;
fr_info_t fi;
nat_t *nat2;
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;
pptp = aps->aps_data;
if (pptp != NULL) {
ip = fin->fin_ip;
p = ip->ip_p;
if ((pptp->pptp_nat == NULL) || (pptp->pptp_state == NULL)) {
bcopy((char *)fin, (char *)&fi, sizeof(fi));
fi.fin_fi.fi_p = IPPROTO_GRE;
fi.fin_fr = &pptpfr;
fi.fin_data[0] = 0;
fi.fin_data[1] = 0;
ip->ip_p = IPPROTO_GRE;
fi.fin_flx &= ~FI_TCPUDP;
fi.fin_flx |= FI_IGNORE;
}
/*
* Update NAT timeout/create NAT if missing.
*/
if (pptp->pptp_nat != NULL)
fr_queueback(&pptp->pptp_nat->nat_tqe);
else {
nat2 = nat_new(&fi, &pptp->pptp_rule, &pptp->pptp_nat,
NAT_SLAVE, nat->nat_dir);
pptp->pptp_nat = nat2;
if (nat2 != NULL) {
(void) nat_proto(&fi, nat2, 0);
nat_update(&fi, nat2, nat2->nat_ptr);
}
}
/*
* Update state timeout/create state if missing.
*/
READ_ENTER(&ipf_state);
if (pptp->pptp_state != NULL) {
fr_queueback(&pptp->pptp_state->is_sti);
RWLOCK_EXIT(&ipf_state);
} else {
RWLOCK_EXIT(&ipf_state);
fi.fin_data[0] = 0;
fi.fin_data[1] = 0;
pptp->pptp_state = fr_addstate(&fi, &pptp->pptp_state,
0);
}
ip->ip_p = p;
}
return 0;
}
/*
* clean up after ourselves.
*/
void ippr_pptp_del(aps)
ap_session_t *aps;
{
pptp_pxy_t *pptp;
pptp = aps->aps_data;
if (pptp != 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 (pptp->pptp_state != NULL) {
pptp->pptp_state->is_die = fr_ticks + 1;
pptp->pptp_state->is_me = NULL;
fr_queuefront(&pptp->pptp_state->is_sti);
}
RWLOCK_EXIT(&ipf_state);
pptp->pptp_state = NULL;
pptp->pptp_nat = NULL;
}
}
int ippr_pptp_match(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
pptp_pxy_t *pptp;
tcphdr_t *tcp;
u_32_t cookie;
pptp = aps->aps_data;
tcp = fin->fin_dp;
if ((pptp != NULL) && (fin->fin_dlen - (TCP_OFF(tcp) << 2) >= 8)) {
u_char *cs;
cs = (u_char *)tcp + (TCP_OFF(tcp) << 2) + 4;
if (pptp->pptp_seencookie == 0) {
pptp->pptp_seencookie = 1;
pptp->pptp_cookie = (cs[0] << 24) | (cs[1] << 16) |
(cs[2] << 8) | cs[3];
} else {
cookie = (cs[0] << 24) | (cs[1] << 16) |
(cs[2] << 8) | cs[3];
if (cookie != pptp->pptp_cookie)
return -1;
}
}
return 0;
}