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freebsd-dev/sys/netinet6/nd6.h
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

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/*-
* 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.
*
* $KAME: nd6.h,v 1.76 2001/12/18 02:10:31 itojun Exp $
* $FreeBSD$
*/
#ifndef _NETINET6_ND6_H_
#define _NETINET6_ND6_H_
/* see net/route.h, or net/if_inarp.h */
#ifndef RTF_ANNOUNCE
#define RTF_ANNOUNCE RTF_PROTO2
#endif
#include <sys/queue.h>
#include <sys/callout.h>
struct llentry;
#define ND6_LLINFO_NOSTATE -2
/*
* We don't need the WAITDELETE state any more, but we keep the definition
* in a comment line instead of removing it. This is necessary to avoid
* unintentionally reusing the value for another purpose, which might
* affect backward compatibility with old applications.
* (20000711 jinmei@kame.net)
*/
/* #define ND6_LLINFO_WAITDELETE -1 */
#define ND6_LLINFO_INCOMPLETE 0
#define ND6_LLINFO_REACHABLE 1
#define ND6_LLINFO_STALE 2
#define ND6_LLINFO_DELAY 3
#define ND6_LLINFO_PROBE 4
#define ND6_IS_LLINFO_PROBREACH(n) ((n)->ln_state > ND6_LLINFO_INCOMPLETE)
#define ND6_LLINFO_PERMANENT(n) (((n)->la_expire == 0) && ((n)->ln_state > ND6_LLINFO_INCOMPLETE))
struct nd_ifinfo {
u_int32_t linkmtu; /* LinkMTU */
u_int32_t maxmtu; /* Upper bound of LinkMTU */
u_int32_t basereachable; /* BaseReachableTime */
u_int32_t reachable; /* Reachable Time */
u_int32_t retrans; /* Retrans Timer */
u_int32_t flags; /* Flags */
int recalctm; /* BaseReacable re-calculation timer */
u_int8_t chlim; /* CurHopLimit */
u_int8_t initialized; /* Flag to see the entry is initialized */
/* the following 3 members are for privacy extension for addrconf */
u_int8_t randomseed0[8]; /* upper 64 bits of MD5 digest */
u_int8_t randomseed1[8]; /* lower 64 bits (usually the EUI64 IFID) */
u_int8_t randomid[8]; /* current random ID */
};
#define ND6_IFF_PERFORMNUD 0x1
#define ND6_IFF_ACCEPT_RTADV 0x2
#define ND6_IFF_PREFER_SOURCE 0x4 /* XXX: not related to ND. */
#define ND6_IFF_IFDISABLED 0x8 /* IPv6 operation is disabled due to
* DAD failure. (XXX: not ND-specific)
*/
#define ND6_IFF_DONT_SET_IFROUTE 0x10
#define ND6_IFF_AUTO_LINKLOCAL 0x20
#define ND6_IFF_NO_RADR 0x40
#define ND6_CREATE LLE_CREATE
#define ND6_EXCLUSIVE LLE_EXCLUSIVE
#ifdef _KERNEL
#define ND_IFINFO(ifp) \
(((struct in6_ifextra *)(ifp)->if_afdata[AF_INET6])->nd_ifinfo)
#define IN6_LINKMTU(ifp) \
((ND_IFINFO(ifp)->linkmtu && ND_IFINFO(ifp)->linkmtu < (ifp)->if_mtu) \
? ND_IFINFO(ifp)->linkmtu \
: ((ND_IFINFO(ifp)->maxmtu && ND_IFINFO(ifp)->maxmtu < (ifp)->if_mtu) \
? ND_IFINFO(ifp)->maxmtu : (ifp)->if_mtu))
#endif
struct in6_nbrinfo {
char ifname[IFNAMSIZ]; /* if name, e.g. "en0" */
struct in6_addr addr; /* IPv6 address of the neighbor */
long asked; /* number of queries already sent for this addr */
int isrouter; /* if it acts as a router */
int state; /* reachability state */
int expire; /* lifetime for NDP state transition */
};
#define DRLSTSIZ 10
#define PRLSTSIZ 10
struct in6_drlist {
char ifname[IFNAMSIZ];
struct {
struct in6_addr rtaddr;
u_char flags;
u_short rtlifetime;
u_long expire;
u_short if_index;
} defrouter[DRLSTSIZ];
};
struct in6_defrouter {
struct sockaddr_in6 rtaddr;
u_char flags;
u_short rtlifetime;
u_long expire;
u_short if_index;
};
#ifdef _KERNEL
struct in6_oprlist {
char ifname[IFNAMSIZ];
struct {
struct in6_addr prefix;
struct prf_ra raflags;
u_char prefixlen;
u_char origin;
u_long vltime;
u_long pltime;
u_long expire;
u_short if_index;
u_short advrtrs; /* number of advertisement routers */
struct in6_addr advrtr[DRLSTSIZ]; /* XXX: explicit limit */
} prefix[PRLSTSIZ];
};
#endif
struct in6_prlist {
char ifname[IFNAMSIZ];
struct {
struct in6_addr prefix;
struct prf_ra raflags;
u_char prefixlen;
u_char origin;
u_int32_t vltime;
u_int32_t pltime;
time_t expire;
u_short if_index;
u_short advrtrs; /* number of advertisement routers */
struct in6_addr advrtr[DRLSTSIZ]; /* XXX: explicit limit */
} prefix[PRLSTSIZ];
};
struct in6_prefix {
struct sockaddr_in6 prefix;
struct prf_ra raflags;
u_char prefixlen;
u_char origin;
u_int32_t vltime;
u_int32_t pltime;
time_t expire;
u_int32_t flags;
int refcnt;
u_short if_index;
u_short advrtrs; /* number of advertisement routers */
/* struct sockaddr_in6 advrtr[] */
};
#ifdef _KERNEL
struct in6_ondireq {
char ifname[IFNAMSIZ];
struct {
u_int32_t linkmtu; /* LinkMTU */
u_int32_t maxmtu; /* Upper bound of LinkMTU */
u_int32_t basereachable; /* BaseReachableTime */
u_int32_t reachable; /* Reachable Time */
u_int32_t retrans; /* Retrans Timer */
u_int32_t flags; /* Flags */
int recalctm; /* BaseReacable re-calculation timer */
u_int8_t chlim; /* CurHopLimit */
u_int8_t receivedra;
} ndi;
};
#endif
struct in6_ndireq {
char ifname[IFNAMSIZ];
struct nd_ifinfo ndi;
};
struct in6_ndifreq {
char ifname[IFNAMSIZ];
u_long ifindex;
};
/* Prefix status */
#define NDPRF_ONLINK 0x1
#define NDPRF_DETACHED 0x2
/* protocol constants */
#define MAX_RTR_SOLICITATION_DELAY 1 /* 1sec */
#define RTR_SOLICITATION_INTERVAL 4 /* 4sec */
#define MAX_RTR_SOLICITATIONS 3
#define ND6_INFINITE_LIFETIME 0xffffffff
#ifdef _KERNEL
/* node constants */
#define MAX_REACHABLE_TIME 3600000 /* msec */
#define REACHABLE_TIME 30000 /* msec */
#define RETRANS_TIMER 1000 /* msec */
#define MIN_RANDOM_FACTOR 512 /* 1024 * 0.5 */
#define MAX_RANDOM_FACTOR 1536 /* 1024 * 1.5 */
#define DEF_TEMP_VALID_LIFETIME 604800 /* 1 week */
#define DEF_TEMP_PREFERRED_LIFETIME 86400 /* 1 day */
#define TEMPADDR_REGEN_ADVANCE 5 /* sec */
#define MAX_TEMP_DESYNC_FACTOR 600 /* 10 min */
#define ND_COMPUTE_RTIME(x) \
(((MIN_RANDOM_FACTOR * (x >> 10)) + (arc4random() & \
((MAX_RANDOM_FACTOR - MIN_RANDOM_FACTOR) * (x >> 10)))) /1000)
TAILQ_HEAD(nd_drhead, nd_defrouter);
struct nd_defrouter {
TAILQ_ENTRY(nd_defrouter) dr_entry;
struct in6_addr rtaddr;
u_char flags; /* flags on RA message */
u_short rtlifetime;
u_long expire;
struct ifnet *ifp;
int installed; /* is installed into kernel routing table */
};
struct nd_prefixctl {
struct ifnet *ndpr_ifp;
/* prefix */
struct sockaddr_in6 ndpr_prefix;
u_char ndpr_plen;
u_int32_t ndpr_vltime; /* advertised valid lifetime */
u_int32_t ndpr_pltime; /* advertised preferred lifetime */
struct prf_ra ndpr_flags;
};
struct nd_prefix {
struct ifnet *ndpr_ifp;
LIST_ENTRY(nd_prefix) ndpr_entry;
struct sockaddr_in6 ndpr_prefix; /* prefix */
struct in6_addr ndpr_mask; /* netmask derived from the prefix */
u_int32_t ndpr_vltime; /* advertised valid lifetime */
u_int32_t ndpr_pltime; /* advertised preferred lifetime */
time_t ndpr_expire; /* expiration time of the prefix */
time_t ndpr_preferred; /* preferred time of the prefix */
time_t ndpr_lastupdate; /* reception time of last advertisement */
struct prf_ra ndpr_flags;
u_int32_t ndpr_stateflags; /* actual state flags */
/* list of routers that advertise the prefix: */
LIST_HEAD(pr_rtrhead, nd_pfxrouter) ndpr_advrtrs;
u_char ndpr_plen;
int ndpr_refcnt; /* reference couter from addresses */
};
#define ndpr_next ndpr_entry.le_next
#define ndpr_raf ndpr_flags
#define ndpr_raf_onlink ndpr_flags.onlink
#define ndpr_raf_auto ndpr_flags.autonomous
#define ndpr_raf_router ndpr_flags.router
/*
* Message format for use in obtaining information about prefixes
* from inet6 sysctl function
*/
struct inet6_ndpr_msghdr {
u_short inpm_msglen; /* to skip over non-understood messages */
u_char inpm_version; /* future binary compatibility */
u_char inpm_type; /* message type */
struct in6_addr inpm_prefix;
u_long prm_vltim;
u_long prm_pltime;
u_long prm_expire;
u_long prm_preferred;
struct in6_prflags prm_flags;
u_short prm_index; /* index for associated ifp */
u_char prm_plen; /* length of prefix in bits */
};
#define prm_raf_onlink prm_flags.prf_ra.onlink
#define prm_raf_auto prm_flags.prf_ra.autonomous
#define prm_statef_onlink prm_flags.prf_state.onlink
#define prm_rrf_decrvalid prm_flags.prf_rr.decrvalid
#define prm_rrf_decrprefd prm_flags.prf_rr.decrprefd
struct nd_pfxrouter {
LIST_ENTRY(nd_pfxrouter) pfr_entry;
#define pfr_next pfr_entry.le_next
struct nd_defrouter *router;
};
LIST_HEAD(nd_prhead, nd_prefix);
/* nd6.c */
VNET_DECLARE(int, nd6_prune);
VNET_DECLARE(int, nd6_delay);
VNET_DECLARE(int, nd6_umaxtries);
VNET_DECLARE(int, nd6_mmaxtries);
VNET_DECLARE(int, nd6_useloopback);
VNET_DECLARE(int, nd6_maxnudhint);
VNET_DECLARE(int, nd6_gctimer);
VNET_DECLARE(struct nd_drhead, nd_defrouter);
VNET_DECLARE(struct nd_prhead, nd_prefix);
VNET_DECLARE(int, nd6_debug);
VNET_DECLARE(int, nd6_onlink_ns_rfc4861);
#define V_nd6_prune VNET(nd6_prune)
#define V_nd6_delay VNET(nd6_delay)
#define V_nd6_umaxtries VNET(nd6_umaxtries)
#define V_nd6_mmaxtries VNET(nd6_mmaxtries)
#define V_nd6_useloopback VNET(nd6_useloopback)
#define V_nd6_maxnudhint VNET(nd6_maxnudhint)
#define V_nd6_gctimer VNET(nd6_gctimer)
#define V_nd_defrouter VNET(nd_defrouter)
#define V_nd_prefix VNET(nd_prefix)
#define V_nd6_debug VNET(nd6_debug)
#define V_nd6_onlink_ns_rfc4861 VNET(nd6_onlink_ns_rfc4861)
#define nd6log(x) do { if (V_nd6_debug) log x; } while (/*CONSTCOND*/ 0)
VNET_DECLARE(struct callout, nd6_timer_ch);
#define V_nd6_timer_ch VNET(nd6_timer_ch)
/* nd6_rtr.c */
VNET_DECLARE(int, nd6_defifindex);
VNET_DECLARE(int, ip6_desync_factor); /* seconds */
VNET_DECLARE(u_int32_t, ip6_temp_preferred_lifetime); /* seconds */
VNET_DECLARE(u_int32_t, ip6_temp_valid_lifetime); /* seconds */
VNET_DECLARE(int, ip6_temp_regen_advance); /* seconds */
#define V_nd6_defifindex VNET(nd6_defifindex)
#define V_ip6_desync_factor VNET(ip6_desync_factor)
#define V_ip6_temp_preferred_lifetime VNET(ip6_temp_preferred_lifetime)
#define V_ip6_temp_valid_lifetime VNET(ip6_temp_valid_lifetime)
#define V_ip6_temp_regen_advance VNET(ip6_temp_regen_advance)
union nd_opts {
struct nd_opt_hdr *nd_opt_array[8]; /* max = target address list */
struct {
struct nd_opt_hdr *zero;
struct nd_opt_hdr *src_lladdr;
struct nd_opt_hdr *tgt_lladdr;
struct nd_opt_prefix_info *pi_beg; /* multiple opts, start */
struct nd_opt_rd_hdr *rh;
struct nd_opt_mtu *mtu;
struct nd_opt_hdr *search; /* multiple opts */
struct nd_opt_hdr *last; /* multiple opts */
int done;
struct nd_opt_prefix_info *pi_end;/* multiple opts, end */
} nd_opt_each;
};
#define nd_opts_src_lladdr nd_opt_each.src_lladdr
#define nd_opts_tgt_lladdr nd_opt_each.tgt_lladdr
#define nd_opts_pi nd_opt_each.pi_beg
#define nd_opts_pi_end nd_opt_each.pi_end
#define nd_opts_rh nd_opt_each.rh
#define nd_opts_mtu nd_opt_each.mtu
#define nd_opts_search nd_opt_each.search
#define nd_opts_last nd_opt_each.last
#define nd_opts_done nd_opt_each.done
/* XXX: need nd6_var.h?? */
/* nd6.c */
void nd6_init __P((void));
#ifdef VIMAGE
void nd6_destroy __P((void));
#endif
struct nd_ifinfo *nd6_ifattach __P((struct ifnet *));
void nd6_ifdetach __P((struct nd_ifinfo *));
int nd6_is_addr_neighbor __P((struct sockaddr_in6 *, struct ifnet *));
void nd6_option_init __P((void *, int, union nd_opts *));
struct nd_opt_hdr *nd6_option __P((union nd_opts *));
int nd6_options __P((union nd_opts *));
struct llentry *nd6_lookup __P((struct in6_addr *, int, struct ifnet *));
void nd6_setmtu __P((struct ifnet *));
void nd6_llinfo_settimer __P((struct llentry *, long));
void nd6_llinfo_settimer_locked __P((struct llentry *, long));
void nd6_timer __P((void *));
void nd6_purge __P((struct ifnet *));
void nd6_nud_hint __P((struct rtentry *, struct in6_addr *, int));
int nd6_resolve __P((struct ifnet *, struct rtentry *, struct mbuf *,
struct sockaddr *, u_char *));
int nd6_ioctl __P((u_long, caddr_t, struct ifnet *));
struct llentry *nd6_cache_lladdr __P((struct ifnet *, struct in6_addr *,
char *, int, int, int));
int nd6_output __P((struct ifnet *, struct ifnet *, struct mbuf *,
struct sockaddr_in6 *, struct rtentry *));
int nd6_output_lle __P((struct ifnet *, struct ifnet *, struct mbuf *,
struct sockaddr_in6 *, struct rtentry *, struct llentry *,
struct mbuf **));
int nd6_output_flush __P((struct ifnet *, struct ifnet *, struct mbuf *,
struct sockaddr_in6 *, struct route *));
int nd6_need_cache __P((struct ifnet *));
int nd6_storelladdr __P((struct ifnet *, struct mbuf *,
struct sockaddr *, u_char *, struct llentry **));
/* nd6_nbr.c */
void nd6_na_input __P((struct mbuf *, int, int));
void nd6_na_output __P((struct ifnet *, const struct in6_addr *,
const struct in6_addr *, u_long, int, struct sockaddr *));
void nd6_ns_input __P((struct mbuf *, int, int));
void nd6_ns_output __P((struct ifnet *, const struct in6_addr *,
const struct in6_addr *, struct llentry *, int));
caddr_t nd6_ifptomac __P((struct ifnet *));
void nd6_dad_start __P((struct ifaddr *, int));
void nd6_dad_stop __P((struct ifaddr *));
void nd6_dad_duplicated __P((struct ifaddr *));
/* nd6_rtr.c */
void nd6_rs_input __P((struct mbuf *, int, int));
void nd6_ra_input __P((struct mbuf *, int, int));
void prelist_del __P((struct nd_prefix *));
void defrouter_addreq __P((struct nd_defrouter *));
void defrouter_reset __P((void));
void defrouter_select __P((void));
void defrtrlist_del __P((struct nd_defrouter *));
void prelist_remove __P((struct nd_prefix *));
int nd6_prelist_add __P((struct nd_prefixctl *, struct nd_defrouter *,
struct nd_prefix **));
int nd6_prefix_onlink __P((struct nd_prefix *));
int nd6_prefix_offlink __P((struct nd_prefix *));
void pfxlist_onlink_check __P((void));
struct nd_defrouter *defrouter_lookup __P((struct in6_addr *, struct ifnet *));
struct nd_prefix *nd6_prefix_lookup __P((struct nd_prefixctl *));
void rt6_flush __P((struct in6_addr *, struct ifnet *));
int nd6_setdefaultiface __P((int));
int in6_tmpifadd __P((const struct in6_ifaddr *, int, int));
#endif /* _KERNEL */
#endif /* _NETINET6_ND6_H_ */
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