freebsd-dev/sbin/ifconfig/af_inet6.c
Hiroki Sato e7fa8d0ada - Accept Router Advertisement messages even when net.inet6.ip6.forwarding=1.
- A new per-interface knob IFF_ND6_NO_RADR and sysctl IPV6CTL_NO_RADR.
  This controls if accepting a route in an RA message as the default route.
  The default value for each interface can be set by net.inet6.ip6.no_radr.
  The system wide default value is 0.

- A new sysctl: net.inet6.ip6.norbit_raif.  This controls if setting R-bit in
  NA on RA accepting interfaces.  The default is 0 (R-bit is set based on
  net.inet6.ip6.forwarding).

Background:

 IPv6 host/router model suggests a router sends an RA and a host accepts it for
 router discovery.  Because of that, KAME implementation does not allow
 accepting RAs when net.inet6.ip6.forwarding=1.  Accepting RAs on a router can
 make the routing table confused since it can change the default router
 unintentionally.

 However, in practice there are cases where we cannot distinguish a host from
 a router clearly.  For example, a customer edge router often works as a host
 against the ISP, and as a router against the LAN at the same time.  Another
 example is a complex network configurations like an L2TP tunnel for IPv6
 connection to Internet over an Ethernet link with another native IPv6 subnet.
 In this case, the physical interface for the native IPv6 subnet works as a
 host, and the pseudo-interface for L2TP works as the default IP forwarding
 route.

Problem:

 Disabling processing RA messages when net.inet6.ip6.forwarding=1 and
 accepting them when net.inet6.ip6.forward=0 cause the following practical
 issues:

 - A router cannot perform SLAAC.  It becomes a problem if a box has
   multiple interfaces and you want to use SLAAC on some of them, for
   example.  A customer edge router for IPv6 Internet access service
   using an IPv6-over-IPv6 tunnel sometimes needs SLAAC on the
   physical interface for administration purpose; updating firmware
   and so on (link-local addresses can be used there, but GUAs by
   SLAAC are often used for scalability).

 - When a host has multiple IPv6 interfaces and it receives multiple RAs on
   them, controlling the default route is difficult.  Router preferences
   defined in RFC 4191 works only when the routers on the links are
   under your control.

Details of Implementation Changes:

 Router Advertisement messages will be accepted even when
 net.inet6.ip6.forwarding=1.  More precisely, the conditions are as
 follow:

 (ACCEPT_RTADV && !NO_RADR && !ip6.forwarding)
	=> Normal RA processing on that interface. (as IPv6 host)

 (ACCEPT_RTADV && (NO_RADR || ip6.forwarding))
	=> Accept RA but add the router to the defroute list with
	   rtlifetime=0 unconditionally.  This effectively prevents
	   from setting the received router address as the box's
	   default route.

 (!ACCEPT_RTADV)
	=> No RA processing on that interface.

 ACCEPT_RTADV and NO_RADR are per-interface knob.  In short, all interface
 are classified as "RA-accepting" or not.  An RA-accepting interface always
 processes RA messages regardless of ip6.forwarding.  The difference caused by
 NO_RADR or ip6.forwarding is whether the RA source address is considered as
 the default router or not.

 R-bit in NA on the RA accepting interfaces is set based on
 net.inet6.ip6.forwarding.  While RFC 6204 W-1 rule (for CPE case) suggests
 a router should disable the R-bit completely even when the box has
 net.inet6.ip6.forwarding=1, I believe there is no technical reason with
 doing so.  This behavior can be set by a new sysctl net.inet6.ip6.norbit_raif
 (the default is 0).

Usage:

 # ifconfig fxp0 inet6 accept_rtadv
	=> accept RA on fxp0
 # ifconfig fxp0 inet6 accept_rtadv no_radr
	=> accept RA on fxp0 but ignore default route information in it.
 # sysctl net.inet6.ip6.norbit_no_radr=1
	=> R-bit in NAs on RA accepting interfaces will always be set to 0.
2011-06-06 02:14:23 +00:00

557 lines
15 KiB
C

/*
* Copyright (c) 1983, 1993
* The Regents of the University of California. 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.
* 4. Neither the name of the University 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 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 <net/if.h>
#include <err.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 <net/if_var.h> /* for struct ifaddr */
#include <netinet/in_var.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <netinet6/nd6.h> /* Define ND6_INFINITE_LIFETIME */
#include "ifconfig.h"
static struct in6_ifreq in6_ridreq;
static struct in6_aliasreq in6_addreq =
{ .ifra_flags = 0,
.ifra_lifetime = { 0, 0, ND6_INFINITE_LIFETIME, ND6_INFINITE_LIFETIME } };
static int ip6lifetime;
static void in6_fillscopeid(struct sockaddr_in6 *sin6);
static int prefix(void *, int);
static char *sec2str(time_t);
static int explicit_prefix = 0;
extern void setnd6flags(const char *, int, int, const struct afswtch *);
extern void setnd6defif(const char *, int, int, const struct afswtch *);
extern void nd6_status(int);
static char addr_buf[MAXHOSTNAMELEN *2 + 1]; /*for getnameinfo()*/
static void
setifprefixlen(const char *addr, int dummy __unused, int s,
const struct afswtch *afp)
{
if (afp->af_getprefix != NULL)
afp->af_getprefix(addr, MASK);
explicit_prefix = 1;
}
static void
setip6flags(const char *dummyaddr __unused, int flag, int dummysoc __unused,
const struct afswtch *afp)
{
if (afp->af_af != AF_INET6)
err(1, "address flags can be set only for inet6 addresses");
if (flag < 0)
in6_addreq.ifra_flags &= ~(-flag);
else
in6_addreq.ifra_flags |= flag;
}
static void
setip6lifetime(const char *cmd, const char *val, int s,
const struct afswtch *afp)
{
time_t newval, t;
char *ep;
t = time(NULL);
newval = (time_t)strtoul(val, &ep, 0);
if (val == ep)
errx(1, "invalid %s", cmd);
if (afp->af_af != AF_INET6)
errx(1, "%s not allowed for the AF", cmd);
if (strcmp(cmd, "vltime") == 0) {
in6_addreq.ifra_lifetime.ia6t_expire = t + newval;
in6_addreq.ifra_lifetime.ia6t_vltime = newval;
} else if (strcmp(cmd, "pltime") == 0) {
in6_addreq.ifra_lifetime.ia6t_preferred = t + newval;
in6_addreq.ifra_lifetime.ia6t_pltime = newval;
}
}
static void
setip6pltime(const char *seconds, int dummy __unused, int s,
const struct afswtch *afp)
{
setip6lifetime("pltime", seconds, s, afp);
}
static void
setip6vltime(const char *seconds, int dummy __unused, int s,
const struct afswtch *afp)
{
setip6lifetime("vltime", seconds, s, afp);
}
static void
setip6eui64(const char *cmd, int dummy __unused, int s,
const struct afswtch *afp)
{
struct ifaddrs *ifap, *ifa;
const struct sockaddr_in6 *sin6 = NULL;
const struct in6_addr *lladdr = NULL;
struct in6_addr *in6;
if (afp->af_af != AF_INET6)
errx(EXIT_FAILURE, "%s not allowed for the AF", cmd);
in6 = (struct in6_addr *)&in6_addreq.ifra_addr.sin6_addr;
if (memcmp(&in6addr_any.s6_addr[8], &in6->s6_addr[8], 8) != 0)
errx(EXIT_FAILURE, "interface index is already filled");
if (getifaddrs(&ifap) != 0)
err(EXIT_FAILURE, "getifaddrs");
for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
if (ifa->ifa_addr->sa_family == AF_INET6 &&
strcmp(ifa->ifa_name, name) == 0) {
sin6 = (const struct sockaddr_in6 *)ifa->ifa_addr;
if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
lladdr = &sin6->sin6_addr;
break;
}
}
}
if (!lladdr)
errx(EXIT_FAILURE, "could not determine link local address");
memcpy(&in6->s6_addr[8], &lladdr->s6_addr[8], 8);
freeifaddrs(ifap);
}
static void
in6_fillscopeid(struct sockaddr_in6 *sin6)
{
#if defined(__KAME__) && defined(KAME_SCOPEID)
if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
sin6->sin6_scope_id =
ntohs(*(u_int16_t *)&sin6->sin6_addr.s6_addr[2]);
sin6->sin6_addr.s6_addr[2] = sin6->sin6_addr.s6_addr[3] = 0;
}
#endif
}
static void
in6_status(int s __unused, const struct ifaddrs *ifa)
{
struct sockaddr_in6 *sin, null_sin;
struct in6_ifreq ifr6;
int s6;
u_int32_t flags6;
struct in6_addrlifetime lifetime;
time_t t = time(NULL);
int error;
u_int32_t scopeid;
memset(&null_sin, 0, sizeof(null_sin));
sin = (struct sockaddr_in6 *)ifa->ifa_addr;
if (sin == NULL)
return;
strncpy(ifr6.ifr_name, ifr.ifr_name, sizeof(ifr.ifr_name));
if ((s6 = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
warn("socket(AF_INET6,SOCK_DGRAM)");
return;
}
ifr6.ifr_addr = *sin;
if (ioctl(s6, SIOCGIFAFLAG_IN6, &ifr6) < 0) {
warn("ioctl(SIOCGIFAFLAG_IN6)");
close(s6);
return;
}
flags6 = ifr6.ifr_ifru.ifru_flags6;
memset(&lifetime, 0, sizeof(lifetime));
ifr6.ifr_addr = *sin;
if (ioctl(s6, SIOCGIFALIFETIME_IN6, &ifr6) < 0) {
warn("ioctl(SIOCGIFALIFETIME_IN6)");
close(s6);
return;
}
lifetime = ifr6.ifr_ifru.ifru_lifetime;
close(s6);
/* XXX: embedded link local addr check */
if (IN6_IS_ADDR_LINKLOCAL(&sin->sin6_addr) &&
*(u_short *)&sin->sin6_addr.s6_addr[2] != 0) {
u_short index;
index = *(u_short *)&sin->sin6_addr.s6_addr[2];
*(u_short *)&sin->sin6_addr.s6_addr[2] = 0;
if (sin->sin6_scope_id == 0)
sin->sin6_scope_id = ntohs(index);
}
scopeid = sin->sin6_scope_id;
error = getnameinfo((struct sockaddr *)sin, sin->sin6_len, addr_buf,
sizeof(addr_buf), NULL, 0, NI_NUMERICHOST);
if (error != 0)
inet_ntop(AF_INET6, &sin->sin6_addr, addr_buf,
sizeof(addr_buf));
printf("\tinet6 %s ", addr_buf);
if (ifa->ifa_flags & IFF_POINTOPOINT) {
sin = (struct sockaddr_in6 *)ifa->ifa_dstaddr;
/*
* some of the interfaces do not have valid destination
* address.
*/
if (sin != NULL && sin->sin6_family == AF_INET6) {
int error;
/* XXX: embedded link local addr check */
if (IN6_IS_ADDR_LINKLOCAL(&sin->sin6_addr) &&
*(u_short *)&sin->sin6_addr.s6_addr[2] != 0) {
u_short index;
index = *(u_short *)&sin->sin6_addr.s6_addr[2];
*(u_short *)&sin->sin6_addr.s6_addr[2] = 0;
if (sin->sin6_scope_id == 0)
sin->sin6_scope_id = ntohs(index);
}
error = getnameinfo((struct sockaddr *)sin,
sin->sin6_len, addr_buf,
sizeof(addr_buf), NULL, 0,
NI_NUMERICHOST);
if (error != 0)
inet_ntop(AF_INET6, &sin->sin6_addr, addr_buf,
sizeof(addr_buf));
printf("--> %s ", addr_buf);
}
}
sin = (struct sockaddr_in6 *)ifa->ifa_netmask;
if (sin == NULL)
sin = &null_sin;
printf("prefixlen %d ", prefix(&sin->sin6_addr,
sizeof(struct in6_addr)));
if ((flags6 & IN6_IFF_ANYCAST) != 0)
printf("anycast ");
if ((flags6 & IN6_IFF_TENTATIVE) != 0)
printf("tentative ");
if ((flags6 & IN6_IFF_DUPLICATED) != 0)
printf("duplicated ");
if ((flags6 & IN6_IFF_DETACHED) != 0)
printf("detached ");
if ((flags6 & IN6_IFF_DEPRECATED) != 0)
printf("deprecated ");
if ((flags6 & IN6_IFF_AUTOCONF) != 0)
printf("autoconf ");
if ((flags6 & IN6_IFF_TEMPORARY) != 0)
printf("temporary ");
if (scopeid)
printf("scopeid 0x%x ", scopeid);
if (ip6lifetime && (lifetime.ia6t_preferred || lifetime.ia6t_expire)) {
printf("pltime ");
if (lifetime.ia6t_preferred) {
printf("%s ", lifetime.ia6t_preferred < t
? "0" : sec2str(lifetime.ia6t_preferred - t));
} else
printf("infty ");
printf("vltime ");
if (lifetime.ia6t_expire) {
printf("%s ", lifetime.ia6t_expire < t
? "0" : sec2str(lifetime.ia6t_expire - t));
} else
printf("infty ");
}
putchar('\n');
}
#define SIN6(x) ((struct sockaddr_in6 *) &(x))
static struct sockaddr_in6 *sin6tab[] = {
SIN6(in6_ridreq.ifr_addr), SIN6(in6_addreq.ifra_addr),
SIN6(in6_addreq.ifra_prefixmask), SIN6(in6_addreq.ifra_dstaddr)
};
static void
in6_getprefix(const char *plen, int which)
{
struct sockaddr_in6 *sin = sin6tab[which];
u_char *cp;
int len = atoi(plen);
if ((len < 0) || (len > 128))
errx(1, "%s: bad value", plen);
sin->sin6_len = sizeof(*sin);
if (which != MASK)
sin->sin6_family = AF_INET6;
if ((len == 0) || (len == 128)) {
memset(&sin->sin6_addr, 0xff, sizeof(struct in6_addr));
return;
}
memset((void *)&sin->sin6_addr, 0x00, sizeof(sin->sin6_addr));
for (cp = (u_char *)&sin->sin6_addr; len > 7; len -= 8)
*cp++ = 0xff;
*cp = 0xff << (8 - len);
}
static void
in6_getaddr(const char *s, int which)
{
struct sockaddr_in6 *sin = sin6tab[which];
struct addrinfo hints, *res;
int error = -1;
newaddr &= 1;
sin->sin6_len = sizeof(*sin);
if (which != MASK)
sin->sin6_family = AF_INET6;
if (which == ADDR) {
char *p = NULL;
if((p = strrchr(s, '/')) != NULL) {
*p = '\0';
in6_getprefix(p + 1, MASK);
explicit_prefix = 1;
}
}
if (sin->sin6_family == AF_INET6) {
bzero(&hints, sizeof(struct addrinfo));
hints.ai_family = AF_INET6;
error = getaddrinfo(s, NULL, &hints, &res);
}
if (error != 0) {
if (inet_pton(AF_INET6, s, &sin->sin6_addr) != 1)
errx(1, "%s: bad value", s);
} else
bcopy(res->ai_addr, sin, res->ai_addrlen);
}
static int
prefix(void *val, int size)
{
u_char *name = (u_char *)val;
int byte, bit, plen = 0;
for (byte = 0; byte < size; byte++, plen += 8)
if (name[byte] != 0xff)
break;
if (byte == size)
return (plen);
for (bit = 7; bit != 0; bit--, plen++)
if (!(name[byte] & (1 << bit)))
break;
for (; bit != 0; bit--)
if (name[byte] & (1 << bit))
return(0);
byte++;
for (; byte < size; byte++)
if (name[byte])
return(0);
return (plen);
}
static char *
sec2str(time_t total)
{
static char result[256];
int days, hours, mins, secs;
int first = 1;
char *p = result;
if (0) {
days = total / 3600 / 24;
hours = (total / 3600) % 24;
mins = (total / 60) % 60;
secs = total % 60;
if (days) {
first = 0;
p += sprintf(p, "%dd", days);
}
if (!first || hours) {
first = 0;
p += sprintf(p, "%dh", hours);
}
if (!first || mins) {
first = 0;
p += sprintf(p, "%dm", mins);
}
sprintf(p, "%ds", secs);
} else
sprintf(result, "%lu", (unsigned long)total);
return(result);
}
static void
in6_postproc(int s, const struct afswtch *afp)
{
if (explicit_prefix == 0) {
/* Aggregatable address architecture defines all prefixes
are 64. So, it is convenient to set prefixlen to 64 if
it is not specified. */
setifprefixlen("64", 0, s, afp);
/* in6_getprefix("64", MASK) if MASK is available here... */
}
}
static void
in6_status_tunnel(int s)
{
char src[NI_MAXHOST];
char dst[NI_MAXHOST];
struct in6_ifreq in6_ifr;
const struct sockaddr *sa = (const struct sockaddr *) &in6_ifr.ifr_addr;
memset(&in6_ifr, 0, sizeof(in6_ifr));
strncpy(in6_ifr.ifr_name, name, IFNAMSIZ);
if (ioctl(s, SIOCGIFPSRCADDR_IN6, (caddr_t)&in6_ifr) < 0)
return;
if (sa->sa_family != AF_INET6)
return;
in6_fillscopeid(&in6_ifr.ifr_addr);
if (getnameinfo(sa, sa->sa_len, src, sizeof(src), 0, 0,
NI_NUMERICHOST) != 0)
src[0] = '\0';
if (ioctl(s, SIOCGIFPDSTADDR_IN6, (caddr_t)&in6_ifr) < 0)
return;
if (sa->sa_family != AF_INET6)
return;
in6_fillscopeid(&in6_ifr.ifr_addr);
if (getnameinfo(sa, sa->sa_len, dst, sizeof(dst), 0, 0,
NI_NUMERICHOST) != 0)
dst[0] = '\0';
printf("\ttunnel inet6 %s --> %s\n", src, dst);
}
static void
in6_set_tunnel(int s, struct addrinfo *srcres, struct addrinfo *dstres)
{
struct in6_aliasreq in6_addreq;
memset(&in6_addreq, 0, sizeof(in6_addreq));
strncpy(in6_addreq.ifra_name, name, IFNAMSIZ);
memcpy(&in6_addreq.ifra_addr, srcres->ai_addr, srcres->ai_addr->sa_len);
memcpy(&in6_addreq.ifra_dstaddr, dstres->ai_addr,
dstres->ai_addr->sa_len);
if (ioctl(s, SIOCSIFPHYADDR_IN6, &in6_addreq) < 0)
warn("SIOCSIFPHYADDR_IN6");
}
static struct cmd inet6_cmds[] = {
DEF_CMD_ARG("prefixlen", setifprefixlen),
DEF_CMD("anycast", IN6_IFF_ANYCAST, setip6flags),
DEF_CMD("tentative", IN6_IFF_TENTATIVE, setip6flags),
DEF_CMD("-tentative", -IN6_IFF_TENTATIVE, setip6flags),
DEF_CMD("deprecated", IN6_IFF_DEPRECATED, setip6flags),
DEF_CMD("-deprecated", -IN6_IFF_DEPRECATED, setip6flags),
DEF_CMD("autoconf", IN6_IFF_AUTOCONF, setip6flags),
DEF_CMD("-autoconf", -IN6_IFF_AUTOCONF, setip6flags),
DEF_CMD("accept_rtadv", ND6_IFF_ACCEPT_RTADV, setnd6flags),
DEF_CMD("-accept_rtadv",-ND6_IFF_ACCEPT_RTADV, setnd6flags),
DEF_CMD("no_radr", ND6_IFF_NO_RADR, setnd6flags),
DEF_CMD("-no_radr", -ND6_IFF_NO_RADR, setnd6flags),
DEF_CMD("defaultif", 1, setnd6defif),
DEF_CMD("-defaultif", -1, setnd6defif),
DEF_CMD("ifdisabled", ND6_IFF_IFDISABLED, setnd6flags),
DEF_CMD("-ifdisabled", -ND6_IFF_IFDISABLED, setnd6flags),
DEF_CMD("nud", ND6_IFF_PERFORMNUD, setnd6flags),
DEF_CMD("-nud", -ND6_IFF_PERFORMNUD, setnd6flags),
DEF_CMD("prefer_source",ND6_IFF_PREFER_SOURCE, setnd6flags),
DEF_CMD("-prefer_source",-ND6_IFF_PREFER_SOURCE,setnd6flags),
DEF_CMD("auto_linklocal",ND6_IFF_AUTO_LINKLOCAL,setnd6flags),
DEF_CMD("-auto_linklocal",-ND6_IFF_AUTO_LINKLOCAL,setnd6flags),
DEF_CMD_ARG("pltime", setip6pltime),
DEF_CMD_ARG("vltime", setip6vltime),
DEF_CMD("eui64", 0, setip6eui64),
};
static struct afswtch af_inet6 = {
.af_name = "inet6",
.af_af = AF_INET6,
.af_status = in6_status,
.af_getaddr = in6_getaddr,
.af_getprefix = in6_getprefix,
.af_other_status = nd6_status,
.af_postproc = in6_postproc,
.af_status_tunnel = in6_status_tunnel,
.af_settunnel = in6_set_tunnel,
.af_difaddr = SIOCDIFADDR_IN6,
.af_aifaddr = SIOCAIFADDR_IN6,
.af_ridreq = &in6_addreq,
.af_addreq = &in6_addreq,
};
static void
in6_Lopt_cb(const char *optarg __unused)
{
ip6lifetime++; /* print IPv6 address lifetime */
}
static struct option in6_Lopt = { .opt = "L", .opt_usage = "[-L]", .cb = in6_Lopt_cb };
static __constructor void
inet6_ctor(void)
{
#define N(a) (sizeof(a) / sizeof(a[0]))
size_t i;
if (!feature_present("inet6"))
return;
for (i = 0; i < N(inet6_cmds); i++)
cmd_register(&inet6_cmds[i]);
af_register(&af_inet6);
opt_register(&in6_Lopt);
#undef N
}