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/* $OpenBSD: filter.c,v 1.21 2015/01/21 21:50:33 deraadt Exp $ */
/*
* Copyright (c) 2004, 2005 Camiel Dobbelaar, <cd@sentia.nl>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <net/pfvar.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "filter.h"
/* From netinet/in.h, but only _KERNEL_ gets them. */
#define satosin(sa) ((struct sockaddr_in *)(sa))
#define satosin6(sa) ((struct sockaddr_in6 *)(sa))
int add_addr(struct sockaddr *, struct pf_pool *);
int prepare_rule(u_int32_t, struct sockaddr *, struct sockaddr *,
u_int16_t);
static struct pfioc_rule pfr;
static struct pfioc_trans pft;
static struct pfioc_trans_e pfte;
static int dev, rule_log;
static char *qname, *tagname;
int
add_addr(struct sockaddr *addr, struct pf_pool *pfp)
{
if (addr->sa_family == AF_INET) {
memcpy(&pfp->addr.v.a.addr.v4,
&satosin(addr)->sin_addr.s_addr, 4);
memset(&pfp->addr.v.a.mask.addr8, 255, 4);
} else {
memcpy(&pfp->addr.v.a.addr.v6,
&satosin6(addr)->sin6_addr.s6_addr, 16);
memset(&pfp->addr.v.a.mask.addr8, 255, 16);
}
pfp->addr.type = PF_ADDR_ADDRMASK;
return (0);
}
int
add_nat(u_int32_t id, struct sockaddr *src, int s_rd, struct sockaddr *dst,
u_int16_t d_port, struct sockaddr *nat, u_int16_t nat_range_low,
u_int16_t nat_range_high)
{
if (!src || !dst || !d_port || !nat || !nat_range_low ||
!nat_range_high || (src->sa_family != nat->sa_family)) {
errno = EINVAL;
return (-1);
}
if (prepare_rule(id, src, dst, d_port) == -1)
return (-1);
if (add_addr(nat, &pfr.rule.nat) == -1)
return (-1);
pfr.rule.direction = PF_OUT;
pfr.rule.onrdomain = s_rd;
pfr.rule.rtableid = -1;
pfr.rule.nat.proxy_port[0] = nat_range_low;
pfr.rule.nat.proxy_port[1] = nat_range_high;
if (ioctl(dev, DIOCADDRULE, &pfr) == -1)
return (-1);
return (0);
}
int
add_rdr(u_int32_t id, struct sockaddr *src, int s_rd, struct sockaddr *dst,
u_int16_t d_port, struct sockaddr *rdr, u_int16_t rdr_port, int d_rd)
{
if (!src || !dst || !d_port || !rdr || !rdr_port ||
(src->sa_family != rdr->sa_family)) {
errno = EINVAL;
return (-1);
}
if (prepare_rule(id, src, dst, d_port) == -1)
return (-1);
if (add_addr(rdr, &pfr.rule.rdr) == -1)
return (-1);
pfr.rule.direction = PF_IN;
pfr.rule.onrdomain = s_rd;
pfr.rule.rtableid = d_rd;
pfr.rule.rdr.proxy_port[0] = rdr_port;
if (ioctl(dev, DIOCADDRULE, &pfr) == -1)
return (-1);
return (0);
}
int
do_commit(void)
{
if (ioctl(dev, DIOCXCOMMIT, &pft) == -1)
return (-1);
return (0);
}
int
do_rollback(void)
{
if (ioctl(dev, DIOCXROLLBACK, &pft) == -1)
return (-1);
return (0);
}
void
init_filter(char *opt_qname, char *opt_tagname, int opt_verbose)
{
struct pf_status status;
qname = opt_qname;
tagname = opt_tagname;
if (opt_verbose == 1)
rule_log = PF_LOG;
else if (opt_verbose == 2)
rule_log = PF_LOG_ALL;
dev = open("/dev/pf", O_RDWR);
if (dev == -1)
err(1, "open /dev/pf");
if (ioctl(dev, DIOCGETSTATUS, &status) == -1)
err(1, "DIOCGETSTATUS");
if (!status.running)
errx(1, "pf is disabled");
}
int
prepare_commit(u_int32_t id)
{
char an[PF_ANCHOR_NAME_SIZE];
memset(&pft, 0, sizeof pft);
pft.size = 1;
pft.esize = sizeof pfte;
pft.array = &pfte;
snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR,
getpid(), id);
memset(&pfte, 0, sizeof pfte);
strlcpy(pfte.anchor, an, PF_ANCHOR_NAME_SIZE);
pfte.type = PF_TRANS_RULESET;
if (ioctl(dev, DIOCXBEGIN, &pft) == -1)
return (-1);
return (0);
}
int
prepare_rule(u_int32_t id, struct sockaddr *src,
struct sockaddr *dst, u_int16_t d_port)
{
char an[PF_ANCHOR_NAME_SIZE];
if ((src->sa_family != AF_INET && src->sa_family != AF_INET6) ||
(src->sa_family != dst->sa_family)) {
errno = EPROTONOSUPPORT;
return (-1);
}
memset(&pfr, 0, sizeof pfr);
snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR,
getpid(), id);
strlcpy(pfr.anchor, an, PF_ANCHOR_NAME_SIZE);
pfr.ticket = pfte.ticket;
/* Generic for all rule types. */
pfr.rule.af = src->sa_family;
pfr.rule.proto = IPPROTO_TCP;
pfr.rule.src.addr.type = PF_ADDR_ADDRMASK;
pfr.rule.dst.addr.type = PF_ADDR_ADDRMASK;
pfr.rule.nat.addr.type = PF_ADDR_NONE;
pfr.rule.rdr.addr.type = PF_ADDR_NONE;
if (src->sa_family == AF_INET) {
memcpy(&pfr.rule.src.addr.v.a.addr.v4,
&satosin(src)->sin_addr.s_addr, 4);
memset(&pfr.rule.src.addr.v.a.mask.addr8, 255, 4);
memcpy(&pfr.rule.dst.addr.v.a.addr.v4,
&satosin(dst)->sin_addr.s_addr, 4);
memset(&pfr.rule.dst.addr.v.a.mask.addr8, 255, 4);
} else {
memcpy(&pfr.rule.src.addr.v.a.addr.v6,
&satosin6(src)->sin6_addr.s6_addr, 16);
memset(&pfr.rule.src.addr.v.a.mask.addr8, 255, 16);
memcpy(&pfr.rule.dst.addr.v.a.addr.v6,
&satosin6(dst)->sin6_addr.s6_addr, 16);
memset(&pfr.rule.dst.addr.v.a.mask.addr8, 255, 16);
}
pfr.rule.dst.port_op = PF_OP_EQ;
pfr.rule.dst.port[0] = htons(d_port);
/*
* pass [quick] [log] inet[6] proto tcp \
* from $src to $dst port = $d_port flags S/SA keep state
* (max 1) [queue qname] [tag tagname]
*/
if (tagname != NULL)
pfr.rule.action = PF_MATCH;
else
pfr.rule.action = PF_PASS;
pfr.rule.quick = 1;
pfr.rule.log = rule_log;
pfr.rule.keep_state = 1;
pfr.rule.flags = TH_SYN;
pfr.rule.flagset = (TH_SYN|TH_ACK);
pfr.rule.max_states = 1;
if (qname != NULL)
strlcpy(pfr.rule.qname, qname, sizeof pfr.rule.qname);
if (tagname != NULL) {
pfr.rule.quick = 0;
strlcpy(pfr.rule.tagname, tagname,
sizeof pfr.rule.tagname);
}
return (0);
}
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