in6_ifattach.c

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//==========================================================================
//
//      src/sys/netinet6/in6_ifattach.c
//
//==========================================================================
//####BSDCOPYRIGHTBEGIN####
//
// -------------------------------------------
//
// Portions of this software may have been derived from OpenBSD, 
// FreeBSD or other sources, and are covered by the appropriate
// copyright disclaimers included herein.
//
// Portions created by Red Hat are
// Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
//
// -------------------------------------------
//
//####BSDCOPYRIGHTEND####
//==========================================================================

/*	$KAME: in6_ifattach.c,v 1.149 2001/12/07 07:07:09 itojun Exp $	*/

/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT 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 PROJECT 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.
 */

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#ifdef __bsdi__
#include <crypto/md5.h>
#elif defined(__OpenBSD__)
#include <sys/md5k.h>
#else
#include <sys/md5.h>
#endif

#ifdef __OpenBSD__
#include <dev/rndvar.h>
#endif

#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/in_var.h>
#ifndef __NetBSD__
#include <netinet/if_ether.h>
#endif
#if (defined(__FreeBSD__) && __FreeBSD__ >= 4)
#include <netinet/in_pcb.h>
#endif

#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/in6_var.h>
#if (defined(__FreeBSD__) && __FreeBSD__ >= 4)
#include <netinet6/in6_pcb.h>
#endif
#include <netinet6/in6_ifattach.h>
#include <netinet6/ip6_var.h>
#include <netinet6/nd6.h>
#include <netinet6/scope6_var.h>

struct in6_ifstat **in6_ifstat = NULL;
struct icmp6_ifstat **icmp6_ifstat = NULL;
size_t in6_ifstatmax = 0;
size_t icmp6_ifstatmax = 0;
unsigned long in6_maxmtu = 0;

#ifdef IP6_AUTO_LINKLOCAL
int ip6_auto_linklocal = IP6_AUTO_LINKLOCAL;
#else
int ip6_auto_linklocal = 1;	/* enable by default */
#endif

#ifdef __NetBSD__
struct callout in6_tmpaddrtimer_ch = CALLOUT_INITIALIZER;
#elif (defined(__FreeBSD__) && __FreeBSD__ >= 3)
struct callout in6_tmpaddrtimer_ch;
#elif defined(__OpenBSD__)
struct timeout in6_tmpaddrtimer_ch;
#endif

#if (defined(__FreeBSD__) && __FreeBSD__ >= 4)
extern struct inpcbinfo udbinfo;
extern struct inpcbinfo ripcbinfo;
#endif

#if defined(__NetBSD__) || defined(__OpenBSD__)
static int get_hostid_ifid __P((struct ifnet *, struct in6_addr *));
#endif
static int get_rand_ifid __P((struct ifnet *, struct in6_addr *));
static int generate_tmp_ifid __P((u_int8_t *, const u_int8_t *, u_int8_t *));
static int get_hw_ifid __P((struct ifnet *, struct in6_addr *));
#ifndef MIP6
static int get_ifid __P((struct ifnet *, struct ifnet *, struct in6_addr *));
#endif /* !MIP6 */
static int in6_ifattach_linklocal __P((struct ifnet *, struct ifnet *));
static int in6_ifattach_loopback __P((struct ifnet *));

#define EUI64_GBIT	0x01
#define EUI64_UBIT	0x02
#define EUI64_TO_IFID(in6)	do {(in6)->s6_addr[8] ^= EUI64_UBIT; } while (0)
#define EUI64_GROUP(in6)	((in6)->s6_addr[8] & EUI64_GBIT)
#define EUI64_INDIVIDUAL(in6)	(!EUI64_GROUP(in6))
#define EUI64_LOCAL(in6)	((in6)->s6_addr[8] & EUI64_UBIT)
#define EUI64_UNIVERSAL(in6)	(!EUI64_LOCAL(in6))

#define IFID_LOCAL(in6)		(!EUI64_LOCAL(in6))
#define IFID_UNIVERSAL(in6)	(!EUI64_UNIVERSAL(in6))

#define GEN_TEMPID_RETRY_MAX 5

#if defined(__NetBSD__) || defined(__OpenBSD__)
/*
 * Generate a last-resort interface identifier from hostid.
 * works only for certain architectures (like sparc).
 * also, using hostid itself may constitute a privacy threat, much worse
 * than MAC addresses (hostids are used for software licensing).
 * maybe we should use MD5(hostid) instead.
 */
static int
get_hostid_ifid(ifp, in6)
	struct ifnet *ifp;
	struct in6_addr *in6;	/* upper 64bits are preserved */
{
	int off, len;
	static u_int8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
	static u_int8_t allone[8] =
		{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };

	if (!hostid)
		return -1;

	/* get up to 8 bytes from the hostid field - should we get */
	len = (sizeof(hostid) > 8) ? 8 : sizeof(hostid);
	off = sizeof(*in6) - len;
	bcopy(&hostid, &in6->s6_addr[off], len);

	/* make sure we do not return anything bogus */
	if (bcmp(&in6->s6_addr[8], allzero, sizeof(allzero)))
		return -1;
	if (bcmp(&in6->s6_addr[8], allone, sizeof(allone)))
		return -1;

	/* make sure to set "u" bit to local, and "g" bit to individual. */
	in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
	in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */

	/* convert EUI64 into IPv6 interface identifier */
	EUI64_TO_IFID(in6);

	return 0;
}
#endif

/*
 * Generate a last-resort interface identifier, when the machine has no
 * IEEE802/EUI64 address sources.
 * The goal here is to get an interface identifier that is
 * (1) random enough and (2) does not change across reboot.
 * We currently use MD5(hostname) for it.
 */
static int
get_rand_ifid(ifp, in6)
	struct ifnet *ifp;
	struct in6_addr *in6;	/* upper 64bits are preserved */
{
	MD5_CTX ctxt;
	u_int8_t digest[16];
#ifdef __FreeBSD__
	int hostnamelen	= strlen(hostname);
#endif

#if 0
	/* we need at least several letters as seed for ifid */
	if (hostnamelen < 3)
		return -1;
#endif

	/* generate 8 bytes of pseudo-random value. */
	bzero(&ctxt, sizeof(ctxt));
	MD5Init(&ctxt);
	MD5Update(&ctxt, hostname, hostnamelen);
	MD5Final(digest, &ctxt);

	/* assumes sizeof(digest) > sizeof(ifid) */
	bcopy(digest, &in6->s6_addr[8], 8);

	/* make sure to set "u" bit to local, and "g" bit to individual. */
	in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
	in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */

	/* convert EUI64 into IPv6 interface identifier */
	EUI64_TO_IFID(in6);

	return 0;
}

static int
generate_tmp_ifid(seed0, seed1, ret)
	u_int8_t *seed0, *ret;
	const u_int8_t *seed1;
{
	MD5_CTX ctxt;
	u_int8_t seed[16], digest[16], nullbuf[8];
	u_int32_t val32;
#ifndef __OpenBSD__
	struct timeval tv;
#endif
	/*
	 * interface ID for subnet anycast addresses.
	 * XXX: we assume the unicast address range that requires IDs
	 * in EUI-64 format.
	 */
	const u_int8_t anycast_id[8] = {0xfd, 0xff, 0xff, 0xff,
					0xff, 0xff, 0xff, 0x80};
	const u_int8_t isatap_id[4] = {0x00, 0x00, 0x5e, 0xfe};
	int badid, retry = 0; 

	/* If there's no hisotry, start with a random seed. */
	bzero(nullbuf, sizeof(nullbuf));
	if (bcmp(nullbuf, seed0, sizeof(nullbuf)) == 0) {
		int i;

		for (i = 0; i < 2; i++) {
#ifndef __OpenBSD__
			microtime(&tv);
			val32 = random() ^ tv.tv_usec;
#else
			val32 = arc4random();
#endif
			bcopy(&val32, seed + sizeof(val32) * i, sizeof(val32));
		}
	} else {
		bcopy(seed0, seed, 8);
	}

	/* copy the right-most 64-bits of the given address */
	/* XXX assumption on the size of IFID */
	bcopy(seed1, &seed[8], 8);

  again:
	if (0) {		/* for debugging purposes only */
		int i;

		printf("generate_tmp_ifid: new randomized ID from: ");
		for (i = 0; i < 16; i++)
			printf("%02x", seed[i]);
		printf(" ");
	}

	/* generate 16 bytes of pseudo-random value. */
	bzero(&ctxt, sizeof(ctxt));
	MD5Init(&ctxt);
	MD5Update(&ctxt, seed, sizeof(seed));
	MD5Final(digest, &ctxt);

	/*
	 * draft-ietf-ipngwg-temp-addresses-v2-00.txt 3.2.1. (3)
	 * Take the left-most 64-bits of the MD5 digest and set bit 6 (the
	 * left-most bit is numbered 0) to zero.
	 */
	bcopy(digest, ret, 8);
	ret[0] &= ~EUI64_UBIT;

	/*
	 * Reject inappropriate identifiers according to
	 * draft-ietf-ipngwg-temp-addresses-v2-00.txt 3.2.1. (4)
	 * At this moment, we reject following cases:
	 * - all 0 identifier
	 * - identifiers that conflict with reserved subnet anycast addresses,
	 *   which are defined in RFC 2526.
	 * - identifiers that conflict with ISATAP addresses
	 * - identifiers used in our own addresses
	 */
	badid = 0;
	if (bcmp(nullbuf, ret, sizeof(nullbuf)) == 0)
		badid = 1;
	else if (bcmp(anycast_id, ret, 7) == 0 &&
	    (anycast_id[7] & ret[7]) == anycast_id[7]) {
		badid = 1;
	} else if (bcmp(isatap_id, ret, sizeof(isatap_id)) == 0)
		badid = 1;
	else {
		struct in6_ifaddr *ia;

		for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
			if (bcmp(&ia->ia_addr.sin6_addr.s6_addr[8], ret, 8)
				== 0) {
				badid = 1;
				break;
			}
		}
	}

	/*
	 * In the event that an unacceptable identifier has been generated,
	 * restart the process, using the right-most 64 bits of the MD5 digest
	 * obtained in place of the history value.
	 */
	if (badid) {
		if (0) {	/* for debugging purposes only */
			int i;

			printf("unacceptable random ID: ");
			for (i = 0; i < 16; i++)
				printf("%02x", digest[i]);
			printf("\n");
		}

		if (++retry < GEN_TEMPID_RETRY_MAX) {
			bcopy(&digest[8], seed, 8);
			goto again;
		} else {
			/*
			 * We're so unlucky.  Give up for now, and return
			 * all 0 IDs to tell the caller not to make a
			 * temporary address.
			 */
			nd6log((LOG_NOTICE,
				"generate_tmp_ifid: never found a good ID\n"));
			bzero(ret, 8);
		}
	}

	/*
	 * draft-ietf-ipngwg-temp-addresses-v2-00.txt 3.2.1. (6)
	 * Take the rightmost 64-bits of the MD5 digest and save them in
	 * stable storage as the history value to be used in the next
	 * iteration of the algorithm. 
	 */
	bcopy(&digest[8], seed0, 8);

	if (0) {		/* for debugging purposes only */
		int i;

		printf("to: ");
		for (i = 0; i < 16; i++)
			printf("%02x", digest[i]);
		printf("\n");
	}

	return 0;
}

/*
 * Get interface identifier for the specified interface.
 * XXX assumes single sockaddr_dl (AF_LINK address) per an interface
 */
static int
get_hw_ifid(ifp, in6)
	struct ifnet *ifp;
	struct in6_addr *in6;	/* upper 64bits are preserved */
{
	struct ifaddr *ifa;
	struct sockaddr_dl *sdl;
	u_int8_t *addr;
	size_t addrlen;
	static u_int8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
	static u_int8_t allone[8] =
		{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };

#if defined(__bsdi__) || (defined(__FreeBSD__) && __FreeBSD__ < 3)
	for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
#else
	for (ifa = ifp->if_addrlist.tqh_first;
	     ifa;
	     ifa = ifa->ifa_list.tqe_next)
#endif
	{
		if (ifa->ifa_addr->sa_family != AF_LINK)
			continue;
		sdl = (struct sockaddr_dl *)ifa->ifa_addr;
		if (sdl == NULL)
			continue;
		if (sdl->sdl_alen == 0)
			continue;

		goto found;
	}

	return -1;

found:
	addr = LLADDR(sdl);
	addrlen = sdl->sdl_alen;

	switch (ifp->if_type) {
	case IFT_IEEE1394:
#ifdef IFT_IEEE80211
	case IFT_IEEE80211:
#endif
		/* IEEE1394 uses 16byte length address starting with EUI64 */
		if (addrlen > 8)
			addrlen = 8;
		break;
	default:
		break;
	}

	/* get EUI64 */
	switch (ifp->if_type) {
	/* IEEE802/EUI64 cases - what others? */
	case IFT_ETHER:
	case IFT_FDDI:
	case IFT_ATM:
	case IFT_IEEE1394:
#ifdef IFT_IEEE80211
	case IFT_IEEE80211:
#endif
		/* look at IEEE802/EUI64 only */
		if (addrlen != 8 && addrlen != 6)
			return -1;

		/*
		 * check for invalid MAC address - on bsdi, we see it a lot
		 * since wildboar configures all-zero MAC on pccard before