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
npf_natlookup(const struct sockaddr_storage * ss,struct sockaddr_storage * nat_addr,in_port_t * nat_lport)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