OpenBSD-4.6/sys/net/pf_lb.c
/* $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);
}