/*	$OpenBSD: pf_lb.c,v 1.5 2009/06/24 13:27:34 sthen Exp $ */

/*
 * Copyright (c) 2001 Daniel Hartmeier
 * Copyright (c) 2002 - 2008 Henning Brauer
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *    - Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *    - Redistributions in binary form must reproduce the above
 *      copyright notice, this list of conditions and the following
 *      disclaimer in the documentation and/or other materials provided
 *      with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * Effort sponsored in part by the Defense Advanced Research Projects
 * Agency (DARPA) and Air Force Research Laboratory, Air Force
 * Materiel Command, USAF, under agreement number F30602-01-2-0537.
 *
 */

#include "bpfilter.h"
#include "pflog.h"
#include "pfsync.h"
#include "pflow.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/filio.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/kernel.h>
#include <sys/time.h>
#include <sys/pool.h>
#include <sys/proc.h>
#include <sys/rwlock.h>

#include <crypto/md5.h>

#include <net/if.h>
#include <net/if_types.h>
#include <net/bpf.h>
#include <net/route.h>
#include <net/radix_mpath.h>

#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/tcp.h>
#include <netinet/tcp_seq.h>
#include <netinet/udp.h>
#include <netinet/ip_icmp.h>
#include <netinet/in_pcb.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet/udp_var.h>
#include <netinet/icmp_var.h>
#include <netinet/if_ether.h>

#include <dev/rndvar.h>
#include <net/pfvar.h>
#include <net/if_pflog.h>
#include <net/if_pflow.h>

#if NPFSYNC > 0
#include <net/if_pfsync.h>
#endif /* NPFSYNC > 0 */

#ifdef INET6
#include <netinet/ip6.h>
#include <netinet/in_pcb.h>
#include <netinet/icmp6.h>
#include <netinet6/nd6.h>
#endif /* INET6 */


#define DPFPRINTF(n, x)	if (pf_status.debug >= (n)) printf x

/*
 * Global variables
 */

void			 pf_hash(struct pf_addr *, struct pf_addr *,
			    struct pf_poolhashkey *, sa_family_t);
struct pf_rule		*pf_match_translation(struct pf_pdesc *, struct mbuf *,
			    int, int, struct pfi_kif *,
			    struct pf_addr *, u_int16_t, struct pf_addr *,
			    u_int16_t, int);
int			 pf_get_sport(sa_family_t, u_int8_t, struct pf_rule *,
			    struct pf_addr *, struct pf_addr *, u_int16_t,
			    struct pf_addr *, u_int16_t*, u_int16_t, u_int16_t,
			    struct pf_src_node **);

#define mix(a,b,c) \
	do {					\
		a -= b; a -= c; a ^= (c >> 13);	\
		b -= c; b -= a; b ^= (a << 8);	\
		c -= a; c -= b; c ^= (b >> 13);	\
		a -= b; a -= c; a ^= (c >> 12);	\
		b -= c; b -= a; b ^= (a << 16);	\
		c -= a; c -= b; c ^= (b >> 5);	\
		a -= b; a -= c; a ^= (c >> 3);	\
		b -= c; b -= a; b ^= (a << 10);	\
		c -= a; c -= b; c ^= (b >> 15);	\
	} while (0)

/*
 * hash function based on bridge_hash in if_bridge.c
 */
void
pf_hash(struct pf_addr *inaddr, struct pf_addr *hash,
    struct pf_poolhashkey *key, sa_family_t af)
{
	u_int32_t	a = 0x9e3779b9, b = 0x9e3779b9, c = key->key32[0];

	switch (af) {
#ifdef INET
	case AF_INET:
		a += inaddr->addr32[0];
		b += key->key32[1];
		mix(a, b, c);
		hash->addr32[0] = c + key->key32[2];
		break;
#endif /* INET */
#ifdef INET6
	case AF_INET6:
		a += inaddr->addr32[0];
		b += inaddr->addr32[2];
		mix(a, b, c);
		hash->addr32[0] = c;
		a += inaddr->addr32[1];
		b += inaddr->addr32[3];
		c += key->key32[1];
		mix(a, b, c);
		hash->addr32[1] = c;
		a += inaddr->addr32[2];
		b += inaddr->addr32[1];
		c += key->key32[2];
		mix(a, b, c);
		hash->addr32[2] = c;
		a += inaddr->addr32[3];
		b += inaddr->addr32[0];
		c += key->key32[3];
		mix(a, b, c);
		hash->addr32[3] = c;
		break;
#endif /* INET6 */
	}
}

struct pf_rule *
pf_match_translation(struct pf_pdesc *pd, struct mbuf *m, int off,
    int direction, struct pfi_kif *kif, struct pf_addr *saddr, u_int16_t sport,
    struct pf_addr *daddr, u_int16_t dport, int rs_num)
{
	struct pf_rule		*r, *rm = NULL;
	struct pf_ruleset	*ruleset = NULL;
	int			 tag = -1;
	int			 rtableid = -1;
	int			 asd = 0;

	r = TAILQ_FIRST(pf_main_ruleset.rules[rs_num].active.ptr);
	while (r && rm == NULL) {
		struct pf_rule_addr	*src = NULL, *dst = NULL;
		struct pf_addr_wrap	*xdst = NULL;

		if (r->action == PF_BINAT && direction == PF_IN) {
			src = &r->dst;
			if (r->rpool.cur != NULL)
				xdst = &r->rpool.cur->addr;
		} else {
			src = &r->src;
			dst = &r->dst;
		}

		r->evaluations++;
		if (pfi_kif_match(r->kif, kif) == r->ifnot)
			r = r->skip[PF_SKIP_IFP].ptr;
		else if (r->direction && r->direction != direction)
			r = r->skip[PF_SKIP_DIR].ptr;
		else if (r->af && r->af != pd->af)
			r = r->skip[PF_SKIP_AF].ptr;
		else if (r->proto && r->proto != pd->proto)
			r = r->skip[PF_SKIP_PROTO].ptr;
		else if (PF_MISMATCHAW(&src->addr, saddr, pd->af,
		    src->neg, kif))
			r = r->skip[src == &r->src ? PF_SKIP_SRC_ADDR :
			    PF_SKIP_DST_ADDR].ptr;
		else if (src->port_op && !pf_match_port(src->port_op,
		    src->port[0], src->port[1], sport))
			r = r->skip[src == &r->src ? PF_SKIP_SRC_PORT :
			    PF_SKIP_DST_PORT].ptr;
		else if (dst != NULL &&
		    PF_MISMATCHAW(&dst->addr, daddr, pd->af, dst->neg, NULL))
			r = r->skip[PF_SKIP_DST_ADDR].ptr;
		else if (xdst != NULL && PF_MISMATCHAW(xdst, daddr, pd->af,
		    0, NULL))
			r = TAILQ_NEXT(r, entries);
		else if (dst != NULL && dst->port_op &&
		    !pf_match_port(dst->port_op, dst->port[0],
		    dst->port[1], dport))
			r = r->skip[PF_SKIP_DST_PORT].ptr;
		else if (r->match_tag && !pf_match_tag(m, r, &tag))
			r = TAILQ_NEXT(r, entries);
		else if (r->os_fingerprint != PF_OSFP_ANY && (pd->proto !=
		    IPPROTO_TCP || !pf_osfp_match(pf_osfp_fingerprint(pd, m,
		    off, pd->hdr.tcp), r->os_fingerprint)))
			r = TAILQ_NEXT(r, entries);
		else {
			if (r->tag)
				tag = r->tag;
			if (r->rtableid >= 0)
				rtableid = r->rtableid;
			if (r->anchor == NULL) {
				rm = r;
			} else
				pf_step_into_anchor(&asd, &ruleset, rs_num,
				    &r, NULL, NULL);
		}
		if (r == NULL)
			pf_step_out_of_anchor(&asd, &ruleset, rs_num, &r,
			    NULL, NULL);
	}
	if (pf_tag_packet(m, tag, rtableid))
		return (NULL);
	if (rm != NULL && (rm->action == PF_NONAT ||
	    rm->action == PF_NORDR || rm->action == PF_NOBINAT))
		return (NULL);
	return (rm);
}

int
pf_get_sport(sa_family_t af, u_int8_t proto, struct pf_rule *r,
    struct pf_addr *saddr, struct pf_addr *daddr, u_int16_t dport,
    struct pf_addr *naddr, u_int16_t *nport, u_int16_t low, u_int16_t high,
    struct pf_src_node **sn)
{
	struct pf_state_key_cmp	key;
	struct pf_addr		init_addr;
	u_int16_t		cut;

	bzero(&init_addr, sizeof(init_addr));
	if (pf_map_addr(af, r, saddr, naddr, &init_addr, sn))
		return (1);

	if (proto == IPPROTO_ICMP || proto == IPPROTO_ICMPV6) {
		if (dport == ICMP6_ECHO_REQUEST || dport == ICMP_ECHO) {
			low = 1;
			high = 65535;
		} else
			return (0);	/* Don't try to modify non-echo ICMP */
	}

	do {
		key.af = af;
		key.proto = proto;
		PF_ACPY(&key.addr[1], daddr, key.af);
		PF_ACPY(&key.addr[0], naddr, key.af);
		key.port[1] = dport;

		/*
		 * port search; start random, step;
		 * similar 2 portloop in in_pcbbind
		 */
		if (!(proto == IPPROTO_TCP || proto == IPPROTO_UDP ||
		    proto == IPPROTO_ICMP)) {
			key.port[0] = dport;
			if (pf_find_state_all(&key, PF_IN, NULL) == NULL)
				return (0);
		} else if (low == 0 && high == 0) {
			key.port[0] = *nport;
			if (pf_find_state_all(&key, PF_IN, NULL) == NULL)
				return (0);
		} else if (low == high) {
			key.port[0] = htons(low);
			if (pf_find_state_all(&key, PF_IN, NULL) == NULL) {
				*nport = htons(low);
				return (0);
			}
		} else {
			u_int16_t tmp;

			if (low > high) {
				tmp = low;
				low = high;
				high = tmp;
			}
			/* low < high */
			cut = arc4random_uniform(1 + high - low) + low;
			/* low <= cut <= high */
			for (tmp = cut; tmp <= high; ++(tmp)) {
				key.port[0] = htons(tmp);
				if (pf_find_state_all(&key, PF_IN, NULL) ==
				    NULL && !in_baddynamic(tmp, proto)) {
					*nport = htons(tmp);
					return (0);
				}
			}
			for (tmp = cut - 1; tmp >= low; --(tmp)) {
				key.port[0] = htons(tmp);
				if (pf_find_state_all(&key, PF_IN, NULL) ==
				    NULL && !in_baddynamic(tmp, proto)) {
					*nport = htons(tmp);
					return (0);
				}
			}
		}

		switch (r->rpool.opts & PF_POOL_TYPEMASK) {
		case PF_POOL_RANDOM:
		case PF_POOL_ROUNDROBIN:
			if (pf_map_addr(af, r, saddr, naddr, &init_addr, sn))
				return (1);
			break;
		case PF_POOL_NONE:
		case PF_POOL_SRCHASH:
		case PF_POOL_BITMASK:
		default:
			return (1);
		}
	} while (! PF_AEQ(&init_addr, naddr, af) );
	return (1);					/* none available */
}

int
pf_map_addr(sa_family_t af, struct pf_rule *r, struct pf_addr *saddr,
    struct pf_addr *naddr, struct pf_addr *init_addr, struct pf_src_node **sn)
{
	unsigned char		 hash[16];
	struct pf_pool		*rpool = &r->rpool;
	struct pf_addr		*raddr = &rpool->cur->addr.v.a.addr;
	struct pf_addr		*rmask = &rpool->cur->addr.v.a.mask;
	struct pf_pooladdr	*acur = rpool->cur;
	struct pf_src_node	 k;

	if (*sn == NULL && r->rpool.opts & PF_POOL_STICKYADDR &&
	    (r->rpool.opts & PF_POOL_TYPEMASK) != PF_POOL_NONE) {
		k.af = af;
		PF_ACPY(&k.addr, saddr, af);
		if (r->rule_flag & PFRULE_RULESRCTRACK ||
		    r->rpool.opts & PF_POOL_STICKYADDR)
			k.rule.ptr = r;
		else
			k.rule.ptr = NULL;
		pf_status.scounters[SCNT_SRC_NODE_SEARCH]++;
		*sn = RB_FIND(pf_src_tree, &tree_src_tracking, &k);
		if (*sn != NULL && !PF_AZERO(&(*sn)->raddr, af)) {
			PF_ACPY(naddr, &(*sn)->raddr, af);
			if (pf_status.debug >= PF_DEBUG_MISC) {
				printf("pf_map_addr: src tracking maps ");
				pf_print_host(&k.addr, 0, af);
				printf(" to ");
				pf_print_host(naddr, 0, af);
				printf("\n");
			}
			return (0);
		}
	}

	if (rpool->cur->addr.type == PF_ADDR_NOROUTE)
		return (1);
	if (rpool->cur->addr.type == PF_ADDR_DYNIFTL) {
		switch (af) {
#ifdef INET
		case AF_INET:
			if (rpool->cur->addr.p.dyn->pfid_acnt4 < 1 &&
			    (rpool->opts & PF_POOL_TYPEMASK) !=
			    PF_POOL_ROUNDROBIN)
				return (1);
			 raddr = &rpool->cur->addr.p.dyn->pfid_addr4;
			 rmask = &rpool->cur->addr.p.dyn->pfid_mask4;
			break;
#endif /* INET */
#ifdef INET6
		case AF_INET6:
			if (rpool->cur->addr.p.dyn->pfid_acnt6 < 1 &&
			    (rpool->opts & PF_POOL_TYPEMASK) !=
			    PF_POOL_ROUNDROBIN)
				return (1);
			raddr = &rpool->cur->addr.p.dyn->pfid_addr6;
			rmask = &rpool->cur->addr.p.dyn->pfid_mask6;
			break;
#endif /* INET6 */
		}
	} else if (rpool->cur->addr.type == PF_ADDR_TABLE) {
		if ((rpool->opts & PF_POOL_TYPEMASK) != PF_POOL_ROUNDROBIN)
			return (1); /* unsupported */
	} else {
		raddr = &rpool->cur->addr.v.a.addr;
		rmask = &rpool->cur->addr.v.a.mask;
	}

	switch (rpool->opts & PF_POOL_TYPEMASK) {
	case PF_POOL_NONE:
		PF_ACPY(naddr, raddr, af);
		break;
	case PF_POOL_BITMASK:
		PF_POOLMASK(naddr, raddr, rmask, saddr, af);
		break;
	case PF_POOL_RANDOM:
		if (init_addr != NULL && PF_AZERO(init_addr, af)) {
			switch (af) {
#ifdef INET
			case AF_INET:
				rpool->counter.addr32[0] = htonl(arc4random());
				break;
#endif /* INET */
#ifdef INET6
			case AF_INET6:
				if (rmask->addr32[3] != 0xffffffff)
					rpool->counter.addr32[3] =
					    htonl(arc4random());
				else
					break;
				if (rmask->addr32[2] != 0xffffffff)
					rpool->counter.addr32[2] =
					    htonl(arc4random());
				else
					break;
				if (rmask->addr32[1] != 0xffffffff)
					rpool->counter.addr32[1] =
					    htonl(arc4random());
				else
					break;
				if (rmask->addr32[0] != 0xffffffff)
					rpool->counter.addr32[0] =
					    htonl(arc4random());
				break;
#endif /* INET6 */
			}
			PF_POOLMASK(naddr, raddr, rmask, &rpool->counter, af);
			PF_ACPY(init_addr, naddr, af);

		} else {
			PF_AINC(&rpool->counter, af);
			PF_POOLMASK(naddr, raddr, rmask, &rpool->counter, af);
		}
		break;
	case PF_POOL_SRCHASH:
		pf_hash(saddr, (struct pf_addr *)&hash, &rpool->key, af);
		PF_POOLMASK(naddr, raddr, rmask, (struct pf_addr *)&hash, af);
		break;
	case PF_POOL_ROUNDROBIN:
		if (rpool->cur->addr.type == PF_ADDR_TABLE) {
			if (!pfr_pool_get(rpool->cur->addr.p.tbl,
			    &rpool->tblidx, &rpool->counter,
			    &raddr, &rmask, af))
				goto get_addr;
		} else if (rpool->cur->addr.type == PF_ADDR_DYNIFTL) {
			if (!pfr_pool_get(rpool->cur->addr.p.dyn->pfid_kt,
			    &rpool->tblidx, &rpool->counter,
			    &raddr, &rmask, af))
				goto get_addr;
		} else if (pf_match_addr(0, raddr, rmask, &rpool->counter, af))
			goto get_addr;

	try_next:
		if ((rpool->cur = TAILQ_NEXT(rpool->cur, entries)) == NULL)
			rpool->cur = TAILQ_FIRST(&rpool->list);
		if (rpool->cur->addr.type == PF_ADDR_TABLE) {
			rpool->tblidx = -1;
			if (pfr_pool_get(rpool->cur->addr.p.tbl,
			    &rpool->tblidx, &rpool->counter,
			    &raddr, &rmask, af)) {
				/* table contains no address of type 'af' */
				if (rpool->cur != acur)
					goto try_next;
				return (1);
			}
		} else if (rpool->cur->addr.type == PF_ADDR_DYNIFTL) {
			rpool->tblidx = -1;
			if (pfr_pool_get(rpool->cur->addr.p.dyn->pfid_kt,
			    &rpool->tblidx, &rpool->counter,
			    &raddr, &rmask, af)) {
				/* table contains no address of type 'af' */
				if (rpool->cur != acur)
					goto try_next;
				return (1);
			}
		} else {
			raddr = &rpool->cur->addr.v.a.addr;
			rmask = &rpool->cur->addr.v.a.mask;
			PF_ACPY(&rpool->counter, raddr, af);
		}

	get_addr:
		PF_ACPY(naddr, &rpool->counter, af);
		if (init_addr != NULL && PF_AZERO(init_addr, af))
			PF_ACPY(init_addr, naddr, af);
		PF_AINC(&rpool->counter, af);
		break;
	}
	if (*sn != NULL)
		PF_ACPY(&(*sn)->raddr, naddr, af);

	if (pf_status.debug >= PF_DEBUG_NOISY &&
	    (rpool->opts & PF_POOL_TYPEMASK) != PF_POOL_NONE) {
		printf("pf_map_addr: selected address ");
		pf_print_host(naddr, 0, af);
		printf("\n");
	}

	return (0);
}

struct pf_rule *
pf_get_translation(struct pf_pdesc *pd, struct mbuf *m, int off, int direction,
    struct pfi_kif *kif, struct pf_src_node **sn,
    struct pf_state_key **skw, struct pf_state_key **sks,
    struct pf_state_key **skp, struct pf_state_key **nkp,
    struct pf_addr *saddr, struct pf_addr *daddr,
    u_int16_t sport, u_int16_t dport)
{
	struct pf_rule	*r = NULL;


	if (direction == PF_OUT) {
		r = pf_match_translation(pd, m, off, direction, kif, saddr,
		    sport, daddr, dport, PF_RULESET_BINAT);
		if (r == NULL)
			r = pf_match_translation(pd, m, off, direction, kif,
			    saddr, sport, daddr, dport, PF_RULESET_NAT);
	} else {
		r = pf_match_translation(pd, m, off, direction, kif, saddr,
		    sport, daddr, dport, PF_RULESET_RDR);
		if (r == NULL)
			r = pf_match_translation(pd, m, off, direction, kif,
			    saddr, sport, daddr, dport, PF_RULESET_BINAT);
	}

	if (r != NULL) {
		struct pf_addr	*naddr;
		u_int16_t	*nport;

		if (pf_state_key_setup(pd, r, skw, sks, skp, nkp,
		    saddr, daddr, sport, dport))
			return r;

		/* XXX We only modify one side for now. */
		naddr = &(*nkp)->addr[1];
		nport = &(*nkp)->port[1];

		switch (r->action) {
		case PF_NONAT:
		case PF_NOBINAT:
		case PF_NORDR:
			return (NULL);
		case PF_NAT:
			if (pf_get_sport(pd->af, pd->proto, r, saddr,
			    daddr, dport, naddr, nport, r->rpool.proxy_port[0],
			    r->rpool.proxy_port[1], sn)) {
				DPFPRINTF(PF_DEBUG_MISC,
				    ("pf: NAT proxy port allocation "
				    "(%u-%u) failed\n",
				    r->rpool.proxy_port[0],
				    r->rpool.proxy_port[1]));
				return (NULL);
			}
			break;
		case PF_BINAT:
			switch (direction) {
			case PF_OUT:
				if (r->rpool.cur->addr.type == PF_ADDR_DYNIFTL){
					switch (pd->af) {
#ifdef INET
					case AF_INET:
						if (r->rpool.cur->addr.p.dyn->
						    pfid_acnt4 < 1)
							return (NULL);
						PF_POOLMASK(naddr,
						    &r->rpool.cur->addr.p.dyn->
						    pfid_addr4,
						    &r->rpool.cur->addr.p.dyn->
						    pfid_mask4,
						    saddr, AF_INET);
						break;
#endif /* INET */
#ifdef INET6
					case AF_INET6:
						if (r->rpool.cur->addr.p.dyn->
						    pfid_acnt6 < 1)
							return (NULL);
						PF_POOLMASK(naddr,
						    &r->rpool.cur->addr.p.dyn->
						    pfid_addr6,
						    &r->rpool.cur->addr.p.dyn->
						    pfid_mask6,
						    saddr, AF_INET6);
						break;
#endif /* INET6 */
					}
				} else
					PF_POOLMASK(naddr,
					    &r->rpool.cur->addr.v.a.addr,
					    &r->rpool.cur->addr.v.a.mask,
					    saddr, pd->af);
				break;
			case PF_IN:
				if (r->src.addr.type == PF_ADDR_DYNIFTL) {
					switch (pd->af) {
#ifdef INET
					case AF_INET:
						if (r->src.addr.p.dyn->
						    pfid_acnt4 < 1)
							return (NULL);
						PF_POOLMASK(naddr,
						    &r->src.addr.p.dyn->
						    pfid_addr4,
						    &r->src.addr.p.dyn->
						    pfid_mask4,
						    daddr, AF_INET);
						break;
#endif /* INET */
#ifdef INET6
					case AF_INET6:
						if (r->src.addr.p.dyn->
						    pfid_acnt6 < 1)
							return (NULL);
						PF_POOLMASK(naddr,
						    &r->src.addr.p.dyn->
						    pfid_addr6,
						    &r->src.addr.p.dyn->
						    pfid_mask6,
						    daddr, AF_INET6);
						break;
#endif /* INET6 */
					}
				} else
					PF_POOLMASK(naddr,
					    &r->src.addr.v.a.addr,
					    &r->src.addr.v.a.mask, daddr,
					    pd->af);
				break;
			}
			break;
		case PF_RDR: {
			if (pf_map_addr(pd->af, r, saddr, naddr, NULL, sn))
				return (NULL);
			if ((r->rpool.opts & PF_POOL_TYPEMASK) ==
			    PF_POOL_BITMASK)
				PF_POOLMASK(naddr, naddr,
				    &r->rpool.cur->addr.v.a.mask, daddr,
				    pd->af);

			if (r->rpool.proxy_port[1]) {
				u_int32_t	tmp_nport;

				tmp_nport = ((ntohs(dport) -
				    ntohs(r->dst.port[0])) %
				    (r->rpool.proxy_port[1] -
				    r->rpool.proxy_port[0] + 1)) +
				    r->rpool.proxy_port[0];

				/* wrap around if necessary */
				if (tmp_nport > 65535)
					tmp_nport -= 65535;
				*nport = htons((u_int16_t)tmp_nport);
			} else if (r->rpool.proxy_port[0])
				*nport = htons(r->rpool.proxy_port[0]);
			break;
		}
		default:
			return (NULL);
		}
		/* 
		 * Translation was a NOP.
		 * Pretend there was no match.
		 */
		if (!bcmp(*skp, *nkp, sizeof(struct pf_state_key_cmp))) {
			pool_put(&pf_state_key_pl, *nkp);
			pool_put(&pf_state_key_pl, *skp);
			*skw = *sks = *nkp = *skp = NULL;
			return (NULL);
		}
	}

	return (r);
}