xref: /freebsd/sys/netpfil/pf/pf_lb.c (revision 4be8e29e776b078b43e95c04259ecebdf407481f)

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * 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.
 *
 *	$OpenBSD: pf_lb.c,v 1.2 2009/02/12 02:13:15 sthen Exp $
 */

#include <sys/cdefs.h>
#include "opt_pf.h"
#include "opt_inet.h"
#include "opt_inet6.h"

#include <sys/param.h>
#include <sys/lock.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/sysctl.h>

#include <net/if.h>
#include <net/if_var.h>
#include <net/vnet.h>
#include <net/pfvar.h>
#include <net/if_pflog.h>

#ifdef INET
#include <netinet/in_var.h>
#endif

#ifdef INET6
#include <netinet6/in6_var.h>
#endif


/*
 * Limit the amount of work we do to find a free source port for redirects that
 * introduce a state conflict.
 */
#define	V_pf_rdr_srcport_rewrite_tries	VNET(pf_rdr_srcport_rewrite_tries)
VNET_DEFINE_STATIC(int, pf_rdr_srcport_rewrite_tries) = 16;

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

static void		 pf_hash(struct pf_addr *, struct pf_addr *,
			    struct pf_poolhashkey *, sa_family_t);
static struct pf_krule	*pf_match_translation(struct pf_pdesc *,
			    int, struct pf_kanchor_stackframe *);
static int pf_get_sport(struct pf_pdesc *, struct pf_krule *,
    struct pf_addr *, uint16_t *, uint16_t, uint16_t, struct pf_ksrc_node **,
    struct pf_srchash **, struct pf_kpool *, struct pf_udp_mapping **);
static bool		 pf_islinklocal(const sa_family_t, const struct pf_addr *);

#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
 */
static 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 */
	}
}

static struct pf_krule *
pf_match_translation(struct pf_pdesc *pd,
    int rs_num, struct pf_kanchor_stackframe *anchor_stack)
{
	struct pf_krule		*r, *rm = NULL;
	struct pf_kruleset	*ruleset = NULL;
	int			 tag = -1;
	int			 rtableid = -1;
	int			 asd = 0;

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

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

		pf_counter_u64_add(&r->evaluations, 1);
		if (pfi_kkif_match(r->kif, pd->kif) == r->ifnot)
			r = r->skip[PF_SKIP_IFP];
		else if (r->direction && r->direction != pd->dir)
			r = r->skip[PF_SKIP_DIR];
		else if (r->af && r->af != pd->af)
			r = r->skip[PF_SKIP_AF];
		else if (r->proto && r->proto != pd->proto)
			r = r->skip[PF_SKIP_PROTO];
		else if (PF_MISMATCHAW(&src->addr, &pd->nsaddr, pd->af,
		    src->neg, pd->kif, M_GETFIB(pd->m)))
			r = r->skip[src == &r->src ? PF_SKIP_SRC_ADDR :
			    PF_SKIP_DST_ADDR];
		else if (src->port_op && !pf_match_port(src->port_op,
		    src->port[0], src->port[1], pd->nsport))
			r = r->skip[src == &r->src ? PF_SKIP_SRC_PORT :
			    PF_SKIP_DST_PORT];
		else if (dst != NULL &&
		    PF_MISMATCHAW(&dst->addr, &pd->ndaddr, pd->af, dst->neg, NULL,
		    M_GETFIB(pd->m)))
			r = r->skip[PF_SKIP_DST_ADDR];
		else if (xdst != NULL && PF_MISMATCHAW(xdst, &pd->ndaddr, pd->af,
		    0, NULL, M_GETFIB(pd->m)))
			r = TAILQ_NEXT(r, entries);
		else if (dst != NULL && dst->port_op &&
		    !pf_match_port(dst->port_op, dst->port[0],
		    dst->port[1], pd->ndport))
			r = r->skip[PF_SKIP_DST_PORT];
		else if (r->match_tag && !pf_match_tag(pd->m, r, &tag,
		    pd->pf_mtag ? pd->pf_mtag->tag : 0))
			r = TAILQ_NEXT(r, entries);
		else if (r->os_fingerprint != PF_OSFP_ANY && (pd->proto !=
		    IPPROTO_TCP || !pf_osfp_match(pf_osfp_fingerprint(pd,
		    &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;
				if (rm->action == PF_NONAT ||
				    rm->action == PF_NORDR ||
				    rm->action == PF_NOBINAT) {
					rm = NULL;
				}
				break;
			} else
				pf_step_into_anchor(anchor_stack, &asd,
				    &ruleset, rs_num, &r, NULL, NULL);
		}
		if (r == NULL)
			pf_step_out_of_anchor(anchor_stack, &asd, &ruleset,
			    rs_num, &r, NULL, NULL);
	}

	if (tag > 0 && pf_tag_packet(pd, tag))
		return (NULL);
	if (rtableid >= 0)
		M_SETFIB(pd->m, rtableid);

	return (rm);
}

static int
pf_get_sport(struct pf_pdesc *pd, struct pf_krule *r,
    struct pf_addr *naddr, uint16_t *nport, uint16_t low,
    uint16_t high, struct pf_ksrc_node **sn,
    struct pf_srchash **sh, struct pf_kpool *rpool,
    struct pf_udp_mapping **udp_mapping)
{
	struct pf_state_key_cmp	key;
	struct pf_addr		init_addr;

	bzero(&init_addr, sizeof(init_addr));

	if (! TAILQ_EMPTY(&r->nat.list) &&
	    pf_map_addr_sn(pd->naf, r, &pd->nsaddr, naddr, NULL, &init_addr,
	    sn, sh, &r->nat))
		return (1);

	if (udp_mapping) {
		MPASS(*udp_mapping == NULL);
	}

	/*
	 * If we are UDP and have an existing mapping we can get source port
	 * from the mapping. In this case we have to look up the src_node as
	 * pf_map_addr would.
	 */
	if (pd->proto == IPPROTO_UDP && (r->rdr.opts & PF_POOL_ENDPI)) {
		struct pf_udp_endpoint_cmp udp_source;

		bzero(&udp_source, sizeof(udp_source));
		udp_source.af = pd->af;
		PF_ACPY(&udp_source.addr, &pd->nsaddr, pd->af);
		udp_source.port = pd->nsport;
		if (udp_mapping) {
			*udp_mapping = pf_udp_mapping_find(&udp_source);
			if (*udp_mapping) {
				PF_ACPY(naddr, &(*udp_mapping)->endpoints[1].addr, pd->af);
				*nport = (*udp_mapping)->endpoints[1].port;
				/* Try to find a src_node as per pf_map_addr(). */
				if (*sn == NULL && r->rdr.opts & PF_POOL_STICKYADDR &&
				    (r->rdr.opts & PF_POOL_TYPEMASK) != PF_POOL_NONE)
					*sn = pf_find_src_node(&pd->nsaddr, r, pd->af, sh, false);
				if (*sn != NULL)
					PF_SRC_NODE_UNLOCK(*sn);
				return (0);
			} else {
				*udp_mapping = pf_udp_mapping_create(pd->af, &pd->nsaddr,
				    pd->nsport, &init_addr, 0);
				if (*udp_mapping == NULL)
					return (1);
			}
		}
	}

	if (pf_map_addr_sn(pd->af, r, &pd->nsaddr, naddr, NULL, &init_addr,
	    sn, sh, rpool))
		goto failed;

	if (pd->proto == IPPROTO_ICMP) {
		if (*nport == htons(ICMP_ECHO)) {
			low = 1;
			high = 65535;
		} else
			return (0);	/* Don't try to modify non-echo ICMP */
	}
#ifdef INET6
	if (pd->proto == IPPROTO_ICMPV6) {
		if (*nport == htons(ICMP6_ECHO_REQUEST)) {
			low = 1;
			high = 65535;
		} else
			return (0);	/* Don't try to modify non-echo ICMP */
	}
#endif /* INET6 */

	bzero(&key, sizeof(key));
	key.af = pd->naf;
	key.proto = pd->proto;
	key.port[0] = pd->ndport;
	PF_ACPY(&key.addr[0], &pd->ndaddr, key.af);

	do {
		PF_ACPY(&key.addr[1], naddr, key.af);
		if (udp_mapping && *udp_mapping)
			PF_ACPY(&(*udp_mapping)->endpoints[1].addr, naddr, pd->af);

		/*
		 * port search; start random, step;
		 * similar 2 portloop in in_pcbbind
		 */
		if (pd->proto == IPPROTO_SCTP) {
			key.port[1] = pd->nsport;
			if (!pf_find_state_all_exists(&key, PF_IN)) {
				*nport = pd->nsport;
				return (0);
			} else {
				return (1); /* Fail mapping. */
			}
		} else if (!(pd->proto == IPPROTO_TCP || pd->proto == IPPROTO_UDP ||
		    pd->proto == IPPROTO_ICMP) || (low == 0 && high == 0)) {
			/*
			 * XXX bug: icmp states don't use the id on both sides.
			 * (traceroute -I through nat)
			 */
			key.port[1] = pd->nsport;
			if (!pf_find_state_all_exists(&key, PF_IN)) {
				*nport = pd->nsport;
				return (0);
			}
		} else if (low == high) {
			key.port[1] = htons(low);
			if (!pf_find_state_all_exists(&key, PF_IN)) {
				if (udp_mapping && *udp_mapping != NULL) {
					(*udp_mapping)->endpoints[1].port = htons(low);
					if (pf_udp_mapping_insert(*udp_mapping) == 0) {
						*nport = htons(low);
						return (0);
					}
				} else {
					*nport = htons(low);
					return (0);
				}
			}
		} else {
			uint32_t tmp;
			uint16_t cut;

			if (low > high) {
				tmp = low;
				low = high;
				high = tmp;
			}
			/* low < high */
			cut = arc4random() % (1 + high - low) + low;
			/* low <= cut <= high */
			for (tmp = cut; tmp <= high && tmp <= 0xffff; ++tmp) {
				if (udp_mapping && *udp_mapping != NULL) {
					(*udp_mapping)->endpoints[1].port = htons(tmp);
					if (pf_udp_mapping_insert(*udp_mapping) == 0) {
						*nport = htons(tmp);
						return (0);
					}
				} else {
					key.port[1] = htons(tmp);
					if (!pf_find_state_all_exists(&key, PF_IN)) {
						*nport = htons(tmp);
						return (0);
					}
				}
			}
			tmp = cut;
			for (tmp -= 1; tmp >= low && tmp <= 0xffff; --tmp) {
				if (pd->proto == IPPROTO_UDP &&
				    (r->rdr.opts & PF_POOL_ENDPI &&
				    udp_mapping != NULL)) {
					(*udp_mapping)->endpoints[1].port = htons(tmp);
					if (pf_udp_mapping_insert(*udp_mapping) == 0) {
						*nport = htons(tmp);
						return (0);
					}
				} else {
					key.port[1] = htons(tmp);
					if (!pf_find_state_all_exists(&key, PF_IN)) {
						*nport = htons(tmp);
						return (0);
					}
				}
			}
		}

		switch (r->rdr.opts & PF_POOL_TYPEMASK) {
		case PF_POOL_RANDOM:
		case PF_POOL_ROUNDROBIN:
			/*
			 * pick a different source address since we're out
			 * of free port choices for the current one.
			 */
			(*sn) = NULL;
			if (pf_map_addr_sn(pd->af, r, &pd->nsaddr, naddr, NULL,
			    &init_addr, sn, sh, &r->rdr))
				return (1);
			break;
		case PF_POOL_NONE:
		case PF_POOL_SRCHASH:
		case PF_POOL_BITMASK:
		default:
			return (1);
		}
	} while (! PF_AEQ(&init_addr, naddr, pd->naf) );

failed:
	if (udp_mapping) {
		uma_zfree(V_pf_udp_mapping_z, *udp_mapping);
		*udp_mapping = NULL;
	}

	return (1);					/* none available */
}

static bool
pf_islinklocal(const sa_family_t af, const struct pf_addr *addr)
{
	if (af == AF_INET6 && IN6_IS_ADDR_LINKLOCAL(&addr->v6))
		return (true);
	return (false);
}

static int
pf_get_mape_sport(struct pf_pdesc *pd, struct pf_krule *r,
    struct pf_addr *naddr, uint16_t *nport,
    struct pf_ksrc_node **sn, struct pf_srchash **sh,
    struct pf_udp_mapping **udp_mapping)
{
	uint16_t psmask, low, highmask;
	uint16_t i, ahigh, cut;
	int ashift, psidshift;

	ashift = 16 - r->rdr.mape.offset;
	psidshift = ashift - r->rdr.mape.psidlen;
	psmask = r->rdr.mape.psid & ((1U << r->rdr.mape.psidlen) - 1);
	psmask = psmask << psidshift;
	highmask = (1U << psidshift) - 1;

	ahigh = (1U << r->rdr.mape.offset) - 1;
	cut = arc4random() & ahigh;
	if (cut == 0)
		cut = 1;

	for (i = cut; i <= ahigh; i++) {
		low = (i << ashift) | psmask;
		if (!pf_get_sport(pd, r,
		    naddr, nport, low, low | highmask, sn, sh, &r->rdr,
		    udp_mapping))
			return (0);
	}
	for (i = cut - 1; i > 0; i--) {
		low = (i << ashift) | psmask;
		if (!pf_get_sport(pd, r,
		    naddr, nport, low, low | highmask, sn, sh, &r->rdr,
		    udp_mapping))
			return (0);
	}
	return (1);
}

u_short
pf_map_addr(sa_family_t af, struct pf_krule *r, struct pf_addr *saddr,
    struct pf_addr *naddr, struct pfi_kkif **nkif, struct pf_addr *init_addr,
    struct pf_kpool *rpool)
{
	u_short			 reason = PFRES_MATCH;
	struct pf_addr		*raddr = NULL, *rmask = NULL;

	mtx_lock(&rpool->mtx);
	/* Find the route using chosen algorithm. Store the found route
	   in src_node if it was given or found. */
	if (rpool->cur->addr.type == PF_ADDR_NOROUTE) {
		reason = PFRES_MAPFAILED;
		goto done_pool_mtx;
	}
	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) {
				reason = PFRES_MAPFAILED;
				goto done_pool_mtx;
			}
			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) {
				reason = PFRES_MAPFAILED;
				goto done_pool_mtx;
			}
			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) {
			reason = PFRES_MAPFAILED;
			goto done_pool_mtx; /* 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:
	    {
		unsigned char hash[16];

		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:
	    {
		struct pf_kpooladdr *acur = rpool->cur;

		if (rpool->cur->addr.type == PF_ADDR_TABLE) {
			if (!pfr_pool_get(rpool->cur->addr.p.tbl,
			    &rpool->tblidx, &rpool->counter, af, NULL))
				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, af, pf_islinklocal))
				goto get_addr;
		} else if (pf_match_addr(0, raddr, rmask, &rpool->counter, af))
			goto get_addr;

	try_next:
		if (TAILQ_NEXT(rpool->cur, entries) == NULL)
			rpool->cur = TAILQ_FIRST(&rpool->list);
		else
			rpool->cur = TAILQ_NEXT(rpool->cur, entries);
		if (rpool->cur->addr.type == PF_ADDR_TABLE) {
			if (pfr_pool_get(rpool->cur->addr.p.tbl,
			    &rpool->tblidx, &rpool->counter, af, NULL)) {
				/* table contains no address of type 'af' */
				if (rpool->cur != acur)
					goto try_next;
				reason = PFRES_MAPFAILED;
				goto done_pool_mtx;
			}
		} 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, af, pf_islinklocal)) {
				/* table contains no address of type 'af' */
				if (rpool->cur != acur)
					goto try_next;
				reason = PFRES_MAPFAILED;
				goto done_pool_mtx;
			}
		} 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 (nkif)
		*nkif = rpool->cur->kif;

done_pool_mtx:
	mtx_unlock(&rpool->mtx);

	if (reason) {
		counter_u64_add(V_pf_status.counters[reason], 1);
	}

	return (reason);
}

u_short
pf_map_addr_sn(sa_family_t af, struct pf_krule *r, struct pf_addr *saddr,
    struct pf_addr *naddr, struct pfi_kkif **nkif, struct pf_addr *init_addr,
    struct pf_ksrc_node **sn, struct pf_srchash **sh, struct pf_kpool *rpool)
{
	u_short			 reason = 0;

	KASSERT(*sn == NULL, ("*sn not NULL"));

	/*
	 * If this is a sticky-address rule, try to find an existing src_node.
	 * Request the sh to be unlocked if sn was not found, as we never
	 * insert a new sn when parsing the ruleset.
	 */
	if (r->rdr.opts & PF_POOL_STICKYADDR &&
	    (r->rdr.opts & PF_POOL_TYPEMASK) != PF_POOL_NONE)
		*sn = pf_find_src_node(saddr, r, af, sh, false);

	if (*sn != NULL) {
		PF_SRC_NODE_LOCK_ASSERT(*sn);

		/* If the supplied address is the same as the current one we've
		 * been asked before, so tell the caller that there's no other
		 * address to be had. */
		if (PF_AEQ(naddr, &(*sn)->raddr, af)) {
			reason = PFRES_MAPFAILED;
			goto done;
		}

		PF_ACPY(naddr, &(*sn)->raddr, af);
		if (nkif)
			*nkif = (*sn)->rkif;
		if (V_pf_status.debug >= PF_DEBUG_NOISY) {
			printf("pf_map_addr: src tracking maps ");
			pf_print_host(saddr, 0, af);
			printf(" to ");
			pf_print_host(naddr, 0, af);
			if (nkif)
				printf("@%s", (*nkif)->pfik_name);
			printf("\n");
		}
		goto done;
	}

	/*
	 * Source node has not been found. Find a new address and store it
	 * in variables given by the caller.
	 */
	if (pf_map_addr(af, r, saddr, naddr, nkif, init_addr, rpool) != 0) {
		/* pf_map_addr() sets reason counters on its own */
		goto done;
	}

	if (V_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);
		if (nkif)
			printf("@%s", (*nkif)->pfik_name);
		printf("\n");
	}

done:
	if ((*sn) != NULL)
		PF_SRC_NODE_UNLOCK(*sn);

	if (reason) {
		counter_u64_add(V_pf_status.counters[reason], 1);
	}

	return (reason);
}

u_short
pf_get_translation(struct pf_pdesc *pd, int off,
    struct pf_state_key **skp, struct pf_state_key **nkp,
    struct pf_kanchor_stackframe *anchor_stack, struct pf_krule **rp,
    struct pf_udp_mapping **udp_mapping)
{
	struct pf_krule	*r = NULL;
	struct pf_addr	*naddr;
	struct pf_ksrc_node	*sn = NULL;
	struct pf_srchash	*sh = NULL;
	uint16_t	*nportp;
	uint16_t	 low, high;
	u_short		 reason;

	PF_RULES_RASSERT();
	KASSERT(*skp == NULL, ("*skp not NULL"));
	KASSERT(*nkp == NULL, ("*nkp not NULL"));

	*rp = NULL;

	if (pd->dir == PF_OUT) {
		r = pf_match_translation(pd, PF_RULESET_BINAT, anchor_stack);
		if (r == NULL)
			r = pf_match_translation(pd, PF_RULESET_NAT, anchor_stack);
	} else {
		r = pf_match_translation(pd, PF_RULESET_RDR, anchor_stack);
		if (r == NULL)
			r = pf_match_translation(pd, PF_RULESET_BINAT, anchor_stack);
	}

	if (r == NULL)
		return (PFRES_MAX);

	switch (r->action) {
	case PF_NONAT:
	case PF_NOBINAT:
	case PF_NORDR:
		return (PFRES_MAX);
	}

	if (pf_state_key_setup(pd, pd->nsport, pd->ndport, skp, nkp))
		return (PFRES_MEMORY);

	naddr = &(*nkp)->addr[1];
	nportp = &(*nkp)->port[1];

	switch (r->action) {
	case PF_NAT:
		if (pd->proto == IPPROTO_ICMP) {
			low = 1;
			high = 65535;
		} else {
			low  = r->rdr.proxy_port[0];
			high = r->rdr.proxy_port[1];
		}
		if (r->rdr.mape.offset > 0) {
			if (pf_get_mape_sport(pd, r, naddr, nportp, &sn,
			    &sh, udp_mapping)) {
				DPFPRINTF(PF_DEBUG_MISC,
				    ("pf: MAP-E port allocation (%u/%u/%u)"
				    " failed\n",
				    r->rdr.mape.offset,
				    r->rdr.mape.psidlen,
				    r->rdr.mape.psid));
				reason = PFRES_MAPFAILED;
				goto notrans;
			}
		} else if (pf_get_sport(pd, r, naddr, nportp, low, high, &sn,
		    &sh, &r->rdr, udp_mapping)) {
			DPFPRINTF(PF_DEBUG_MISC,
			    ("pf: NAT proxy port allocation (%u-%u) failed\n",
			    r->rdr.proxy_port[0], r->rdr.proxy_port[1]));
			reason = PFRES_MAPFAILED;
			goto notrans;
		}
		break;
	case PF_BINAT:
		switch (pd->dir) {
		case PF_OUT:
			if (r->rdr.cur->addr.type == PF_ADDR_DYNIFTL){
				switch (pd->af) {
#ifdef INET
				case AF_INET:
					if (r->rdr.cur->addr.p.dyn->
					    pfid_acnt4 < 1) {
						reason = PFRES_MAPFAILED;
						goto notrans;
					}
					PF_POOLMASK(naddr,
					    &r->rdr.cur->addr.p.dyn->
					    pfid_addr4,
					    &r->rdr.cur->addr.p.dyn->
					    pfid_mask4, &pd->nsaddr, AF_INET);
					break;
#endif /* INET */
#ifdef INET6
				case AF_INET6:
					if (r->rdr.cur->addr.p.dyn->
					    pfid_acnt6 < 1) {
						reason = PFRES_MAPFAILED;
						goto notrans;
					}
					PF_POOLMASK(naddr,
					    &r->rdr.cur->addr.p.dyn->
					    pfid_addr6,
					    &r->rdr.cur->addr.p.dyn->
					    pfid_mask6, &pd->nsaddr, AF_INET6);
					break;
#endif /* INET6 */
				}
			} else
				PF_POOLMASK(naddr,
				    &r->rdr.cur->addr.v.a.addr,
				    &r->rdr.cur->addr.v.a.mask, &pd->nsaddr,
				    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) {
						reason = PFRES_MAPFAILED;
						goto notrans;
					}
					PF_POOLMASK(naddr,
					    &r->src.addr.p.dyn->pfid_addr4,
					    &r->src.addr.p.dyn->pfid_mask4,
					    &pd->ndaddr, AF_INET);
					break;
#endif /* INET */
#ifdef INET6
				case AF_INET6:
					if (r->src.addr.p.dyn->pfid_acnt6 < 1) {
						reason = PFRES_MAPFAILED;
						goto notrans;
					}
					PF_POOLMASK(naddr,
					    &r->src.addr.p.dyn->pfid_addr6,
					    &r->src.addr.p.dyn->pfid_mask6,
					    &pd->ndaddr, AF_INET6);
					break;
#endif /* INET6 */
				}
			} else
				PF_POOLMASK(naddr, &r->src.addr.v.a.addr,
				    &r->src.addr.v.a.mask, &pd->ndaddr, pd->af);
			break;
		}
		break;
	case PF_RDR: {
		struct pf_state_key_cmp key;
		int tries;
		uint16_t cut, low, high, nport;

		reason = pf_map_addr_sn(pd->af, r, &pd->nsaddr, naddr, NULL,
		    NULL, &sn, &sh, &r->rdr);
		if (reason != 0)
			goto notrans;
		if ((r->rdr.opts & PF_POOL_TYPEMASK) == PF_POOL_BITMASK)
			PF_POOLMASK(naddr, naddr, &r->rdr.cur->addr.v.a.mask,
			    &pd->ndaddr, pd->af);

		/* Do not change SCTP ports. */
		if (pd->proto == IPPROTO_SCTP)
			break;

		if (r->rdr.proxy_port[1]) {
			uint32_t	tmp_nport;

			tmp_nport = ((ntohs(pd->ndport) - ntohs(r->dst.port[0])) %
			    (r->rdr.proxy_port[1] - r->rdr.proxy_port[0] +
			    1)) + r->rdr.proxy_port[0];

			/* Wrap around if necessary. */
			if (tmp_nport > 65535)
				tmp_nport -= 65535;
			nport = htons((uint16_t)tmp_nport);
		} else if (r->rdr.proxy_port[0])
			nport = htons(r->rdr.proxy_port[0]);
		else
			nport = pd->ndport;

		/*
		 * Update the destination port.
		 */
		*nportp = nport;

		/*
		 * Do we have a source port conflict in the stack state?  Try to
		 * modulate the source port if so.  Note that this is racy since
		 * the state lookup may not find any matches here but will once
		 * pf_create_state() actually instantiates the state.
		 */
		bzero(&key, sizeof(key));
		key.af = pd->af;
		key.proto = pd->proto;
		key.port[0] = pd->nsport;
		PF_ACPY(&key.addr[0], &pd->nsaddr, key.af);
		key.port[1] = nport;
		PF_ACPY(&key.addr[1], naddr, key.af);

		if (!pf_find_state_all_exists(&key, PF_OUT))
			break;

		tries = 0;

		low = 50001;	/* XXX-MJ PF_NAT_PROXY_PORT_LOW/HIGH */
		high = 65535;
		cut = arc4random() % (1 + high - low) + low;
		for (uint32_t tmp = cut;
		    tmp <= high && tmp <= UINT16_MAX &&
		    tries < V_pf_rdr_srcport_rewrite_tries;
		    tmp++, tries++) {
			key.port[0] = htons(tmp);
			if (!pf_find_state_all_exists(&key, PF_OUT)) {
				/* Update the source port. */
				(*nkp)->port[0] = htons(tmp);
				goto out;
			}
		}
		for (uint32_t tmp = cut - 1;
		    tmp >= low && tries < V_pf_rdr_srcport_rewrite_tries;
		    tmp--, tries++) {
			key.port[0] = htons(tmp);
			if (!pf_find_state_all_exists(&key, PF_OUT)) {
				/* Update the source port. */
				(*nkp)->port[0] = htons(tmp);
				goto out;
			}
		}

		/*
		 * We failed to find a match.  Push on ahead anyway, let
		 * pf_state_insert() be the arbiter of whether the state
		 * conflict is tolerable.  In particular, with TCP connections
		 * the state may be reused if the TCP state is terminal.
		 */
		DPFPRINTF(PF_DEBUG_MISC,
		    ("pf: RDR source port allocation failed\n"));
		break;

out:
		DPFPRINTF(PF_DEBUG_MISC,
		    ("pf: RDR source port allocation %u->%u\n",
		    ntohs(pd->nsport), ntohs((*nkp)->port[0])));
		break;
	}
	default:
		panic("%s: unknown action %u", __func__, r->action);
	}

	/* Return success only if translation really happened. */
	if (bcmp(*skp, *nkp, sizeof(struct pf_state_key_cmp))) {
		*rp = r;
		return (PFRES_MATCH);
	}

	reason = PFRES_MAX;
notrans:
	uma_zfree(V_pf_state_key_z, *nkp);
	uma_zfree(V_pf_state_key_z, *skp);
	*skp = *nkp = NULL;

	return (reason);
}

int
pf_get_transaddr_af(struct pf_krule *r, struct pf_pdesc *pd)
{
#if defined(INET) && defined(INET6)
	struct pf_addr	 ndaddr, nsaddr, naddr;
	u_int16_t	 nport = 0;
	int		 prefixlen = 96;
	struct pf_srchash	*sh = NULL;
	struct pf_ksrc_node	*sns = NULL;

	bzero(&nsaddr, sizeof(nsaddr));
	bzero(&ndaddr, sizeof(ndaddr));

	if (V_pf_status.debug >= PF_DEBUG_MISC) {
		printf("pf: af-to %s %s, ",
		    pd->naf == AF_INET ? "inet" : "inet6",
		    TAILQ_EMPTY(&r->rdr.list) ? "nat" : "rdr");
		pf_print_host(&pd->nsaddr, pd->nsport, pd->af);
		printf(" -> ");
		pf_print_host(&pd->ndaddr, pd->ndport, pd->af);
		printf("\n");
	}

	if (TAILQ_EMPTY(&r->nat.list))
		panic("pf_get_transaddr_af: no nat pool for source address");

	/* get source address and port */
	if (pf_get_sport(pd, r, &nsaddr, &nport,
	    r->nat.proxy_port[0], r->nat.proxy_port[1], &sns, &sh, &r->nat, NULL)) {
		DPFPRINTF(PF_DEBUG_MISC,
		    ("pf: af-to NAT proxy port allocation (%u-%u) failed",
		    r->nat.proxy_port[0], r->nat.proxy_port[1]));
		return (-1);
	}

	if (pd->proto == IPPROTO_ICMPV6 && pd->naf == AF_INET) {
		if (pd->dir == PF_IN) {
			NTOHS(pd->ndport);
			if (pd->ndport == ICMP6_ECHO_REQUEST)
				pd->ndport = ICMP_ECHO;
			else if (pd->ndport == ICMP6_ECHO_REPLY)
				pd->ndport = ICMP_ECHOREPLY;
			HTONS(pd->ndport);
		} else {
			NTOHS(pd->nsport);
			if (pd->nsport == ICMP6_ECHO_REQUEST)
				pd->nsport = ICMP_ECHO;
			else if (pd->nsport == ICMP6_ECHO_REPLY)
				pd->nsport = ICMP_ECHOREPLY;
			HTONS(pd->nsport);
		}
	} else if (pd->proto == IPPROTO_ICMP && pd->naf == AF_INET6) {
		if (pd->dir == PF_IN) {
			NTOHS(pd->ndport);
			if (pd->ndport == ICMP_ECHO)
				pd->ndport = ICMP6_ECHO_REQUEST;
			else if (pd->ndport == ICMP_ECHOREPLY)
				pd->ndport = ICMP6_ECHO_REPLY;
			HTONS(pd->ndport);
		} else {
			NTOHS(pd->nsport);
			if (pd->nsport == ICMP_ECHO)
				pd->nsport = ICMP6_ECHO_REQUEST;
			else if (pd->nsport == ICMP_ECHOREPLY)
				pd->nsport = ICMP6_ECHO_REPLY;
			HTONS(pd->nsport);
		}
	}

	/* get the destination address and port */
	if (! TAILQ_EMPTY(&r->rdr.list)) {
		if (pf_map_addr_sn(pd->naf, r, &nsaddr, &naddr, NULL, NULL,
		    &sns, NULL, &r->rdr))
			return (-1);
		if (r->rdr.proxy_port[0])
			pd->ndport = htons(r->rdr.proxy_port[0]);

		if (pd->naf == AF_INET) {
			/* The prefix is the IPv4 rdr address */
			prefixlen = in_mask2len(
			    (struct in_addr *)&r->rdr.cur->addr.v.a.mask);
			inet_nat46(pd->naf, &pd->ndaddr, &ndaddr, &naddr,
			    prefixlen);
		} else {
			/* The prefix is the IPv6 rdr address */
			prefixlen = in6_mask2len(
			    (struct in6_addr *)&r->rdr.cur->addr.v.a.mask, NULL);
			inet_nat64(pd->naf, &pd->ndaddr, &ndaddr, &naddr,
			    prefixlen);
		}
	} else {
		if (pd->naf == AF_INET) {
			/* The prefix is the IPv6 dst address */
			prefixlen = in6_mask2len(
			    (struct in6_addr *)&r->dst.addr.v.a.mask, NULL);
			if (prefixlen < 32)
				prefixlen = 96;
			inet_nat64(pd->naf, &pd->ndaddr, &ndaddr, &pd->ndaddr,
			    prefixlen);
		} else {
			/*
			 * The prefix is the IPv6 nat address
			 * (that was stored in pd->nsaddr)
			 */
			prefixlen = in6_mask2len(
			    (struct in6_addr *)&r->nat.cur->addr.v.a.mask, NULL);
			if (prefixlen > 96)
				prefixlen = 96;
			inet_nat64(pd->naf, &pd->ndaddr, &ndaddr, &nsaddr,
			    prefixlen);
		}
	}

	PF_ACPY(&pd->nsaddr, &nsaddr, pd->naf);
	PF_ACPY(&pd->ndaddr, &ndaddr, pd->naf);

	if (V_pf_status.debug >= PF_DEBUG_MISC) {
		printf("pf: af-to %s done, prefixlen %d, ",
		    pd->naf == AF_INET ? "inet" : "inet6",
		    prefixlen);
		pf_print_host(&pd->nsaddr, pd->nsport, pd->naf);
		printf(" -> ");
		pf_print_host(&pd->ndaddr, pd->ndport, pd->naf);
		printf("\n");
	}

	return (0);
#else
	return (-1);
#endif
}