102 lines
2.5 KiB
C
102 lines
2.5 KiB
C
/* $NetBSD: ipf.c,v 1.4 2018/12/13 13:11:28 sborrill Exp $ */
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/*
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* ipf.c - NAT lookup code for IP Filter.
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*
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* This software is in the public domain.
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* Written by Peter Postma <peter@NetBSD.org>
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*/
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: ipf.c,v 1.4 2018/12/13 13:11:28 sborrill Exp $");
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/ioctl.h>
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#include <sys/fcntl.h>
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#include <net/if.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ipl.h>
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#include <netinet/ip_compat.h>
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#include <netinet/ip_fil.h>
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#include <netinet/ip_nat.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syslog.h>
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#include <unistd.h>
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#include "identd.h"
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int
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ipf_natlookup(const struct sockaddr_storage *ss,
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struct sockaddr_storage *nat_addr, in_port_t *nat_lport)
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{
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natlookup_t nl;
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ipfobj_t obj;
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int dev;
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(void)memset(&obj, 0, sizeof(obj));
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(void)memset(&nl, 0, sizeof(nl));
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/* Build the ipf object description structure. */
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obj.ipfo_rev = IPFILTER_VERSION;
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obj.ipfo_size = sizeof(nl);
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obj.ipfo_ptr = &nl;
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obj.ipfo_type = IPFOBJ_NATLOOKUP;
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/* Build the ipf natlook structure. */
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switch (ss[0].ss_family) {
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case AF_INET:
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(void)memcpy(&nl.nl_realip, &csatosin(&ss[0])->sin_addr,
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sizeof(struct in_addr));
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(void)memcpy(&nl.nl_outip, &csatosin(&ss[1])->sin_addr,
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sizeof(struct in_addr));
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nl.nl_realport = ntohs(csatosin(&ss[0])->sin_port);
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nl.nl_outport = ntohs(csatosin(&ss[1])->sin_port);
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nl.nl_flags = IPN_TCP | IPN_IN;
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nl.nl_v = 4; /* IPv4 */
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break;
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case AF_INET6:
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/* XXX IP Filter doesn't support IPv6 NAT yet. */
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default:
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maybe_syslog(LOG_ERR, "Unsupported protocol for NAT lookup "
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"(no. %d)", ss[0].ss_family);
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return 0;
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}
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/* Open the NAT device and do the lookup. */
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if ((dev = open(IPNAT_NAME, O_RDONLY)) == -1) {
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maybe_syslog(LOG_ERR, "Cannot open %s: %m", IPNAT_NAME);
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return 0;
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}
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if (ioctl(dev, SIOCGNATL, &obj) == -1) {
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maybe_syslog(LOG_ERR, "NAT lookup failure: %m");
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(void)close(dev);
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return 0;
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}
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(void)close(dev);
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/*
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* Put the originating address into nat_addr and fill
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* the port with the ident port, 113.
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*/
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switch (ss[0].ss_family) {
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case AF_INET:
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(void)memcpy(&satosin(nat_addr)->sin_addr, &nl.nl_inip,
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sizeof(struct in_addr));
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satosin(nat_addr)->sin_port = htons(113);
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satosin(nat_addr)->sin_len = sizeof(struct sockaddr_in);
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satosin(nat_addr)->sin_family = AF_INET;
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break;
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case AF_INET6:
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break;
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}
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/* Put the originating port into nat_lport. */
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*nat_lport = nl.nl_inport;
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return 1;
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}
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