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/*
* Copyright (C) 2011 by Darren Reed.
*
* See the IPFILTER.LICENCE file for details on licencing.
*
* $Id$
*
* Simple RCMD transparent proxy for in-kernel use. For use with the NAT
* code.
*/
#define IPF_RCMD_PROXY
typedef struct rcmdinfo {
u_32_t rcmd_port; /* Port number seen */
u_32_t rcmd_portseq; /* Sequence number where port is first seen */
ipnat_t *rcmd_rule; /* Template rule for back connection */
} rcmdinfo_t;
void ipf_p_rcmd_main_load __P((void));
void ipf_p_rcmd_main_unload __P((void));
int ipf_p_rcmd_init __P((void));
void ipf_p_rcmd_fini __P((void));
void ipf_p_rcmd_del __P((ipf_main_softc_t *, ap_session_t *));
int ipf_p_rcmd_new __P((void *, fr_info_t *, ap_session_t *, nat_t *));
int ipf_p_rcmd_out __P((void *, fr_info_t *, ap_session_t *, nat_t *));
int ipf_p_rcmd_in __P((void *, fr_info_t *, ap_session_t *, nat_t *));
u_short ipf_rcmd_atoi __P((char *));
int ipf_p_rcmd_portmsg __P((fr_info_t *, ap_session_t *, nat_t *));
static frentry_t rcmdfr;
static int rcmd_proxy_init = 0;
/*
* RCMD application proxy initialization.
*/
void
ipf_p_rcmd_main_load()
{
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;
}
void
ipf_p_rcmd_main_unload()
{
if (rcmd_proxy_init == 1) {
MUTEX_DESTROY(&rcmdfr.fr_lock);
rcmd_proxy_init = 0;
}
}
/*
* Setup for a new RCMD proxy.
*/
int
ipf_p_rcmd_new(arg, fin, aps, nat)
void *arg;
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
tcphdr_t *tcp = (tcphdr_t *)fin->fin_dp;
rcmdinfo_t *rc;
ipnat_t *ipn;
ipnat_t *np;
int size;
fin = fin; /* LINT */
np = nat->nat_ptr;
size = np->in_size;
KMALLOC(rc, rcmdinfo_t *);
if (rc == NULL) {
#ifdef IP_RCMD_PROXY_DEBUG
printf("ipf_p_rcmd_new:KMALLOCS(%d) failed\n", sizeof(*rc));
#endif
return -1;
}
KMALLOCS(ipn, ipnat_t *, size);
if (ipn == NULL) {
KFREE(rc);
return -1;
}
aps->aps_data = rc;
aps->aps_psiz = sizeof(*rc);
bzero((char *)rc, sizeof(*rc));
bzero((char *)ipn, size);
rc->rcmd_rule = ipn;
aps->aps_sport = tcp->th_sport;
aps->aps_dport = tcp->th_dport;
ipn->in_size = size;
ipn->in_ifps[0] = nat->nat_ifps[0];
ipn->in_ifps[1] = nat->nat_ifps[1];
ipn->in_apr = NULL;
ipn->in_use = 1;
ipn->in_hits = 1;
ipn->in_ippip = 1;
if ((np->in_redir & NAT_REDIRECT) != 0) {
ipn->in_redir = NAT_MAP;
ipn->in_snip = ntohl(nat->nat_odstaddr);
ipn->in_nsrcaddr = nat->nat_odstaddr;
ipn->in_dnip = ntohl(nat->nat_nsrcaddr);
ipn->in_ndstaddr = nat->nat_nsrcaddr;
ipn->in_osrcaddr = nat->nat_ndstaddr;
ipn->in_odstaddr = nat->nat_osrcaddr;
} else {
ipn->in_redir = NAT_REDIRECT;
ipn->in_snip = ntohl(nat->nat_odstaddr);
ipn->in_nsrcaddr = nat->nat_odstaddr;
ipn->in_dnip = ntohl(nat->nat_osrcaddr);
ipn->in_ndstaddr = nat->nat_osrcaddr;
ipn->in_osrcaddr = nat->nat_ndstaddr;
ipn->in_odstaddr = nat->nat_nsrcaddr;
}
ipn->in_osrcmsk = 0xffffffff;
ipn->in_nsrcmsk = 0xffffffff;
ipn->in_odstmsk = 0xffffffff;
ipn->in_ndstmsk = 0xffffffff;
ipn->in_pr[0] = IPPROTO_TCP;
ipn->in_pr[1] = IPPROTO_TCP;
ipn->in_flags = (np->in_flags | IPN_PROXYRULE);
MUTEX_INIT(&ipn->in_lock, "rcmd proxy NAT rule");
ipn->in_namelen = np->in_namelen;
bcopy(np->in_names, ipn->in_ifnames, ipn->in_namelen);
ipn->in_ifnames[0] = nat->nat_ptr->in_ifnames[0];
ipn->in_ifnames[1] = nat->nat_ptr->in_ifnames[1];
return 0;
}
void
ipf_p_rcmd_del(softc, aps)
ipf_main_softc_t *softc;
ap_session_t *aps;
{
rcmdinfo_t *rci;
rci = aps->aps_data;
if (rci != NULL) {
rci->rcmd_rule->in_flags |= IPN_DELETE;
ipf_nat_rule_deref(softc, &rci->rcmd_rule);
}
}
/*
* 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
ipf_p_rcmd_portmsg(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
tcphdr_t *tcp, tcph, *tcp2 = &tcph;
int off, dlen, nflags, direction;
ipf_main_softc_t *softc;
char portbuf[8], *s;
rcmdinfo_t *rc;
fr_info_t fi;
u_short sp;
nat_t *nat2;
ip_t *ip;
mb_t *m;
tcp = (tcphdr_t *)fin->fin_dp;
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;
rc = (rcmdinfo_t *)aps->aps_data;
if ((rc->rcmd_portseq != 0) &&
(tcp->th_seq != rc->rcmd_portseq))
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("ipf_p_rcmd_portmsg:sp == 0 dlen %d [%s]\n",
dlen, portbuf);
#endif
return 0;
}
if (rc->rcmd_port != 0 && sp != rc->rcmd_port) {
#ifdef IP_RCMD_PROXY_DEBUG
printf("ipf_p_rcmd_portmsg:sp(%d) != rcmd_port(%d)\n",
sp, rc->rcmd_port);
#endif
return 0;
}
rc->rcmd_port = sp;
rc->rcmd_portseq = tcp->th_seq;
/*
* Initialise the packet info structure so we can search the NAT
* table to see if there already is soemthing present that matches
* up with what we want to add.
*/
bcopy((char *)fin, (char *)&fi, sizeof(fi));
fi.fin_flx |= FI_IGNORE;
fi.fin_data[0] = 0;
fi.fin_data[1] = sp;
fi.fin_fi.fi_saddr = nat->nat_ndstaddr;
fi.fin_fi.fi_daddr = nat->nat_nsrcaddr;
if (nat->nat_dir == NAT_OUTBOUND) {
nat2 = ipf_nat_outlookup(&fi, NAT_SEARCH|IPN_TCP,
nat->nat_pr[1],
nat->nat_osrcip, nat->nat_odstip);
} else {
nat2 = ipf_nat_inlookup(&fi, NAT_SEARCH|IPN_TCP,
nat->nat_pr[0],
nat->nat_osrcip, nat->nat_odstip);
}
softc = fin->fin_main_soft;
if (nat2 == NULL) {
#ifdef USE_MUTEXES
ipf_nat_softc_t *softn = softc->ipf_nat_soft;
#endif
/*
* Add skeleton NAT entry for connection which will come
* back the other way.
*/
int slen;
slen = ip->ip_len;
ip->ip_len = htons(fin->fin_hlen + sizeof(*tcp));
/*
* Fill out the fake TCP header with a few fields that ipfilter
* considers to be important.
*/
bzero((char *)tcp2, sizeof(*tcp2));
tcp2->th_win = htons(8192);
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);
if (nat->nat_dir == NAT_OUTBOUND) {
fi.fin_out = 0;
direction = NAT_INBOUND;
} else {
fi.fin_out = 1;
direction = NAT_OUTBOUND;
}
nflags = SI_W_SPORT;
fi.fin_flx &= FI_LOWTTL|FI_FRAG|FI_TCPUDP|FI_OPTIONS|FI_IGNORE;
nflags |= NAT_SLAVE|IPN_TCP;
MUTEX_ENTER(&softn->ipf_nat_new);
nat2 = ipf_nat_add(&fi, rc->rcmd_rule, NULL, nflags,
direction);
MUTEX_EXIT(&softn->ipf_nat_new);
if (nat2 != NULL) {
(void) ipf_nat_proto(&fi, nat2, IPN_TCP);
MUTEX_ENTER(&nat2->nat_lock);
ipf_nat_update(&fi, nat2);
MUTEX_EXIT(&nat2->nat_lock);
fi.fin_ifp = NULL;
if (nat2->nat_dir == NAT_INBOUND)
fi.fin_fi.fi_daddr = nat->nat_osrcaddr;
(void) ipf_state_add(softc, &fi, NULL, SI_W_SPORT);
}
ip->ip_len = slen;
}
return 0;
}
int
ipf_p_rcmd_out(arg, fin, aps, nat)
void *arg;
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
if (nat->nat_dir == NAT_OUTBOUND)
return ipf_p_rcmd_portmsg(fin, aps, nat);
return 0;
}
int
ipf_p_rcmd_in(arg, fin, aps, nat)
void *arg;
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
if (nat->nat_dir == NAT_INBOUND)
return ipf_p_rcmd_portmsg(fin, aps, nat);
return 0;
}