freebsd-skq/sbin/ifconfig/af_nd6.c
Bjoern A. Zeeb 201100c58b Initial implementation of draft-ietf-6man-ipv6only-flag.
This change defines the RA "6" (IPv6-Only) flag which routers
may advertise, kernel logic to check if all routers on a link
have the flag set and accordingly update a per-interface flag.

If all routers agree that it is an IPv6-only link, ether_output_frame(),
based on the interface flag, will filter out all ETHERTYPE_IP/ARP
frames, drop them, and return EAFNOSUPPORT to upper layers.

The change also updates ndp to show the "6" flag, ifconfig to
display the IPV6_ONLY nd6 flag if set, and rtadvd to allow
announcing the flag.

Further changes to tcpdump (contrib code) are availble and will
be upstreamed.

Tested the code (slightly earlier version) with 2 FreeBSD
IPv6 routers, a FreeBSD laptop on ethernet as well as wifi,
and with Win10 and OSX clients (which did not fall over with
the "6" flag set but not understood).

We may also want to (a) implement and RX filter, and (b) over
time enahnce user space to, say, stop dhclient from running
when the interface flag is set.  Also we might want to start
IPv6 before IPv4 in the future.

All the code is hidden under the EXPERIMENTAL option and not
compiled by default as the draft is a work-in-progress and
we cannot rely on the fact that IANA will assign the bits
as requested by the draft and hence they may change.

Dear 6man, you have running code.

Discussed with:	Bob Hinden, Brian E Carpenter
2018-10-30 20:08:48 +00:00

179 lines
4.7 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2009 Hiroki Sato. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*/
#ifndef lint
static const char rcsid[] =
"$FreeBSD$";
#endif /* not lint */
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/route.h>
#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ifaddrs.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <netinet6/nd6.h>
#include "ifconfig.h"
#define MAX_SYSCTL_TRY 5
#ifdef DRAFT_IETF_6MAN_IPV6ONLY_FLAG
#define ND6BITS "\020\001PERFORMNUD\002ACCEPT_RTADV\003PREFER_SOURCE" \
"\004IFDISABLED\005DONT_SET_IFROUTE\006AUTO_LINKLOCAL" \
"\007NO_RADR\010NO_PREFER_IFACE\011NO_DAD" \
"\012IPV6_ONLY" \
"\020DEFAULTIF"
#else
#define ND6BITS "\020\001PERFORMNUD\002ACCEPT_RTADV\003PREFER_SOURCE" \
"\004IFDISABLED\005DONT_SET_IFROUTE\006AUTO_LINKLOCAL" \
"\007NO_RADR\010NO_PREFER_IFACE\011NO_DAD\020DEFAULTIF"
#endif
static int isnd6defif(int);
void setnd6flags(const char *, int, int, const struct afswtch *);
void setnd6defif(const char *, int, int, const struct afswtch *);
void nd6_status(int);
void
setnd6flags(const char *dummyaddr __unused,
int d, int s,
const struct afswtch *afp)
{
struct in6_ndireq nd;
int error;
memset(&nd, 0, sizeof(nd));
strlcpy(nd.ifname, ifr.ifr_name, sizeof(nd.ifname));
error = ioctl(s, SIOCGIFINFO_IN6, &nd);
if (error) {
warn("ioctl(SIOCGIFINFO_IN6)");
return;
}
if (d < 0)
nd.ndi.flags &= ~(-d);
else
nd.ndi.flags |= d;
error = ioctl(s, SIOCSIFINFO_IN6, (caddr_t)&nd);
if (error)
warn("ioctl(SIOCSIFINFO_IN6)");
}
void
setnd6defif(const char *dummyaddr __unused,
int d, int s,
const struct afswtch *afp)
{
struct in6_ndifreq ndifreq;
int ifindex;
int error;
memset(&ndifreq, 0, sizeof(ndifreq));
strlcpy(ndifreq.ifname, ifr.ifr_name, sizeof(ndifreq.ifname));
if (d < 0) {
if (isnd6defif(s)) {
/* ifindex = 0 means to remove default if */
ifindex = 0;
} else
return;
} else if ((ifindex = if_nametoindex(ndifreq.ifname)) == 0) {
warn("if_nametoindex(%s)", ndifreq.ifname);
return;
}
ndifreq.ifindex = ifindex;
error = ioctl(s, SIOCSDEFIFACE_IN6, (caddr_t)&ndifreq);
if (error)
warn("ioctl(SIOCSDEFIFACE_IN6)");
}
static int
isnd6defif(int s)
{
struct in6_ndifreq ndifreq;
unsigned int ifindex;
int error;
memset(&ndifreq, 0, sizeof(ndifreq));
strlcpy(ndifreq.ifname, ifr.ifr_name, sizeof(ndifreq.ifname));
ifindex = if_nametoindex(ndifreq.ifname);
error = ioctl(s, SIOCGDEFIFACE_IN6, (caddr_t)&ndifreq);
if (error) {
warn("ioctl(SIOCGDEFIFACE_IN6)");
return (error);
}
return (ndifreq.ifindex == ifindex);
}
void
nd6_status(int s)
{
struct in6_ndireq nd;
int s6;
int error;
int isdefif;
memset(&nd, 0, sizeof(nd));
strlcpy(nd.ifname, ifr.ifr_name, sizeof(nd.ifname));
if ((s6 = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
if (errno != EAFNOSUPPORT && errno != EPROTONOSUPPORT)
warn("socket(AF_INET6, SOCK_DGRAM)");
return;
}
error = ioctl(s6, SIOCGIFINFO_IN6, &nd);
if (error) {
if (errno != EPFNOSUPPORT)
warn("ioctl(SIOCGIFINFO_IN6)");
close(s6);
return;
}
isdefif = isnd6defif(s6);
close(s6);
if (nd.ndi.flags == 0 && !isdefif)
return;
printb("\tnd6 options",
(unsigned int)(nd.ndi.flags | (isdefif << 15)), ND6BITS);
putchar('\n');
}