Home | History | Annotate | Line # | Download | only in identd 
      1 /*	$NetBSD: npf.c,v 1.2 2016/12/10 22:09:18 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2016 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Christos Zoulas.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __RCSID("$NetBSD: npf.c,v 1.2 2016/12/10 22:09:18 christos Exp $");
     34 
     35 #include <sys/types.h>
     36 #include <sys/socket.h>
     37 #include <sys/ioctl.h>
     38 #include <sys/fcntl.h>
     39 
     40 #include <net/if.h>
     41 #include <netinet/in.h>
     42 
     43 #include <npf.h>
     44 #include <stdlib.h>
     45 #include <string.h>
     46 #include <errno.h>
     47 #include <syslog.h>
     48 #include <unistd.h>
     49 
     50 #include "identd.h"
     51 
     52 int
     53 npf_natlookup(const struct sockaddr_storage *ss,
     54     struct sockaddr_storage *nat_addr, in_port_t *nat_lport)
     55 {
     56 	npf_addr_t *addr[2];
     57 	in_port_t port[2];
     58 	int dev, af;
     59 
     60 	/* copy the source into nat_addr so it is writable */
     61 	memcpy(nat_addr, &ss[0], sizeof(ss[0]));
     62 
     63 	switch (af = ss[0].ss_family) {
     64 	case AF_INET:
     65 		addr[0] = (void *)&satosin(nat_addr)->sin_addr;
     66 		addr[1] = __UNCONST(&csatosin(&ss[1])->sin_addr);
     67 		port[0] = csatosin(&ss[0])->sin_port;
     68 		port[1] = csatosin(&ss[1])->sin_port;
     69 		break;
     70 	case AF_INET6:
     71 		addr[0] = (void *)&satosin6(&nat_addr)->sin6_addr;
     72 		addr[1] = __UNCONST(&csatosin6(&ss[0])->sin6_addr);
     73 		port[0] = csatosin6(&ss[0])->sin6_port;
     74 		port[1] = csatosin6(&ss[1])->sin6_port;
     75 		break;
     76 	default:
     77 		errno = EAFNOSUPPORT;
     78 		maybe_syslog(LOG_ERR, "NAT lookup for %d: %m" , af);
     79 		return 0;
     80 	}
     81 
     82 	/* Open the /dev/pf device and do the lookup. */
     83 	if ((dev = open("/dev/npf", O_RDWR)) == -1) {
     84 		maybe_syslog(LOG_ERR, "Cannot open /dev/npf: %m");
     85 		return 0;
     86 	}
     87 	if (npf_nat_lookup(dev, af, addr, port, IPPROTO_TCP, PFIL_OUT) == -1) {
     88 		maybe_syslog(LOG_ERR, "NAT lookup failure: %m");
     89 		(void)close(dev);
     90 		return 0;
     91 	}
     92 	(void)close(dev);
     93 
     94 	/*
     95 	 * The originating address is already set into nat_addr so fill
     96 	 * in the rest, family, port (ident), len....
     97 	 */
     98 	switch (af) {
     99 	case AF_INET:
    100 		satosin(nat_addr)->sin_port = htons(113);
    101 		satosin(nat_addr)->sin_len = sizeof(struct sockaddr_in);
    102 		satosin(nat_addr)->sin_family = AF_INET;
    103 		break;
    104 	case AF_INET6:
    105 		satosin6(nat_addr)->sin6_port = htons(113);
    106 		satosin6(nat_addr)->sin6_len = sizeof(struct sockaddr_in6);
    107 		satosin6(nat_addr)->sin6_family = AF_INET6;
    108 		break;
    109 	}
    110 	/* Put the originating port into nat_lport. */
    111 	*nat_lport = ntohs(port[0]);
    112 
    113 	return 1;
    114 }
    115