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|
/* $OpenBSD: pf_lb.c,v 1.12 2010/02/04 14:10:12 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 <sys/syslog.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 */
/*
* Global variables
*/
void pf_hash(struct pf_addr *, struct pf_addr *,
struct pf_poolhashkey *, sa_family_t);
int pf_get_sport(sa_family_t, u_int8_t, struct pf_rule *,
struct pf_addr *, u_int16_t, struct pf_addr *,
u_int16_t, struct pf_addr *, u_int16_t *,
u_int16_t, u_int16_t, struct pf_src_node **, int);
#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 */
}
}
int
pf_get_sport(sa_family_t af, u_int8_t proto, struct pf_rule *r,
struct pf_addr *saddr, u_int16_t sport,
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, int rdomain)
{
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, &r->nat,
PF_SN_NAT))
return (1);
if (proto == IPPROTO_ICMP || proto == IPPROTO_ICMPV6) {
if (dport == htons(ICMP6_ECHO_REQUEST) ||
dport == htons(ICMP_ECHO)) {
low = 1;
high = 65535;
} else
return (0); /* Don't try to modify non-echo ICMP */
}
do {
key.af = af;
key.proto = proto;
key.rdomain = rdomain;
PF_ACPY(&key.addr[0], daddr, key.af);
PF_ACPY(&key.addr[1], naddr, key.af);
key.port[0] = dport;
/*
* port search; start random, step;
* similar 2 portloop in in_pcbbind
*/
if (!(proto == IPPROTO_TCP || proto == IPPROTO_UDP ||
proto == IPPROTO_ICMP)) {
/* XXX bug: icmp states dont use the id on both
* XXX sides (traceroute -I through nat) */
key.port[1] = sport;
if (pf_find_state_all(&key, PF_IN, NULL) == NULL) {
*nport = sport;
return (0);
}
} else if (low == 0 && high == 0) {
key.port[1] = sport;
if (pf_find_state_all(&key, PF_IN, NULL) == NULL) {
*nport = sport;
return (0);
}
} else if (low == high) {
key.port[1] = 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[1] = 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[1] = htons(tmp);
if (pf_find_state_all(&key, PF_IN, NULL) ==
NULL && !in_baddynamic(tmp, proto)) {
*nport = htons(tmp);
return (0);
}
}
}
switch (r->nat.opts & PF_POOL_TYPEMASK) {
case PF_POOL_RANDOM:
case PF_POOL_ROUNDROBIN:
if (pf_map_addr(af, r, saddr, naddr, &init_addr, sn,
&r->nat, PF_SN_NAT))
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 **sns,
struct pf_pool *rpool, enum pf_sn_types type)
{
unsigned char hash[16];
struct pf_addr *raddr = &rpool->addr.v.a.addr;
struct pf_addr *rmask = &rpool->addr.v.a.mask;
struct pf_src_node k;
if (sns[type] == NULL && rpool->opts & PF_POOL_STICKYADDR &&
(rpool->opts & PF_POOL_TYPEMASK) != PF_POOL_NONE) {
k.af = af;
k.type = type;
PF_ACPY(&k.addr, saddr, af);
k.rule.ptr = r;
pf_status.scounters[SCNT_SRC_NODE_SEARCH]++;
sns[type] = RB_FIND(pf_src_tree, &tree_src_tracking, &k);
if (sns[type] != NULL) {
if (!PF_AZERO(&(sns[type])->raddr, af))
PF_ACPY(naddr, &(sns[type])->raddr, af);
if (pf_status.debug >= LOG_DEBUG) {
log(LOG_DEBUG, "pf: pf_map_addr: "
"src tracking (%u) maps ", type);
pf_print_host(&k.addr, 0, af);
addlog(" to ");
pf_print_host(naddr, 0, af);
addlog("\n");
}
return (0);
}
}
if (rpool->addr.type == PF_ADDR_NOROUTE)
return (1);
if (rpool->addr.type == PF_ADDR_DYNIFTL) {
switch (af) {
#ifdef INET
case AF_INET:
if (rpool->addr.p.dyn->pfid_acnt4 < 1 &&
(rpool->opts & PF_POOL_TYPEMASK) !=
PF_POOL_ROUNDROBIN)
return (1);
raddr = &rpool->addr.p.dyn->pfid_addr4;
rmask = &rpool->addr.p.dyn->pfid_mask4;
break;
#endif /* INET */
#ifdef INET6
case AF_INET6:
if (rpool->addr.p.dyn->pfid_acnt6 < 1 &&
(rpool->opts & PF_POOL_TYPEMASK) !=
PF_POOL_ROUNDROBIN)
return (1);
raddr = &rpool->addr.p.dyn->pfid_addr6;
rmask = &rpool->addr.p.dyn->pfid_mask6;
break;
#endif /* INET6 */
}
} else if (rpool->addr.type == PF_ADDR_TABLE) {
if ((rpool->opts & PF_POOL_TYPEMASK) != PF_POOL_ROUNDROBIN)
return (1); /* unsupported */
} else {
raddr = &rpool->addr.v.a.addr;
rmask = &rpool->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->addr.type == PF_ADDR_TABLE) {
if (pfr_pool_get(rpool->addr.p.tbl,
&rpool->tblidx, &rpool->counter,
&raddr, &rmask, &rpool->kif, af))
return (1);
} else if (rpool->addr.type == PF_ADDR_DYNIFTL) {
if (pfr_pool_get(rpool->addr.p.dyn->pfid_kt,
&rpool->tblidx, &rpool->counter,
&raddr, &rmask, &rpool->kif, af))
return (1);
} else if (pf_match_addr(0, raddr, rmask, &rpool->counter, af))
return (1);
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 (rpool->opts & PF_POOL_STICKYADDR) {
if (sns[type] != NULL) {
pf_remove_src_node(sns[type]);
sns[type] = NULL;
}
if (pf_insert_src_node(&sns[type], r, type, af, saddr, naddr,
0))
return (1);
}
if (pf_status.debug >= LOG_NOTICE &&
(rpool->opts & PF_POOL_TYPEMASK) != PF_POOL_NONE) {
log(LOG_NOTICE, "pf: pf_map_addr: selected address ");
pf_print_host(naddr, 0, af);
addlog("\n");
}
return (0);
}
int
pf_get_transaddr(struct pf_rule *r, struct pf_pdesc *pd, struct pf_addr *saddr,
u_int16_t *sport, struct pf_addr *daddr, u_int16_t *dport,
struct pf_src_node **sns)
{
struct pf_addr naddr;
u_int16_t nport = 0;
if (r->nat.addr.type != PF_ADDR_NONE) {
/* XXX is this right? what if rtable is changed at the same
* XXX time? where do I need to figure out the sport? */
if (pf_get_sport(pd->af, pd->proto, r, saddr, *sport,
daddr, *dport, &naddr, &nport, r->nat.proxy_port[0],
r->nat.proxy_port[1], sns, pd->rdomain)) {
DPFPRINTF(LOG_NOTICE,
"pf: NAT proxy port allocation (%u-%u) failed",
r->nat.proxy_port[0],
r->nat.proxy_port[1]);
return (-1);
}
PF_ACPY(saddr, &naddr, pd->af);
*sport = nport;
}
if (r->rdr.addr.type != PF_ADDR_NONE) {
if (pf_map_addr(pd->af, r, saddr, &naddr, NULL, sns, &r->rdr,
PF_SN_RDR))
return (-1);
if ((r->rdr.opts & PF_POOL_TYPEMASK) == PF_POOL_BITMASK)
PF_POOLMASK(&naddr, &naddr, &r->rdr.addr.v.a.mask,
daddr, pd->af);
if (r->rdr.proxy_port[1]) {
u_int32_t tmp_nport;
tmp_nport = ((ntohs(*dport) -
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((u_int16_t)tmp_nport);
} else if (r->rdr.proxy_port[0])
nport = htons(r->rdr.proxy_port[0]);
PF_ACPY(daddr, &naddr, pd->af);
if (nport)
*dport = nport;
}
return (0);
}
|