struct in6_addr *
in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
struct ip6_moptions *mopts, struct route *ro,
struct ifnet **ifpp, struct in6_addr *laddr,
int *errorp)
{
struct in6_addr *dst;
struct ifnet *ifp = NULL;
struct in6_ifaddr *ia = NULL, *ia_best = NULL;
struct in6_pktinfo *pi = NULL;
int dst_scope = -1, best_scope = -1, best_matchlen = -1;
struct in6_addrpolicy *dst_policy = NULL, *best_policy = NULL;
#ifdef MIP6
struct hif_softc *sc;
#ifdef MIP6_ALLOW_COA_FALLBACK
struct mip6_bu *mbu_dst;
u_int8_t coafallback = 0;
#endif
#endif
dst = &dstsock->sin6_addr;
*errorp = 0;
if (ifpp)
*ifpp = NULL;
/*
* If the source address is explicitly specified by the caller,
* check if the requested source address is indeed a unicast address
* assigned to the node, and can be used as the packet's source
* address. If everything is okay, use the address as source.
*/
if (opts && (pi = opts->ip6po_pktinfo) &&
!IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) {
struct sockaddr_in6 srcsock;
struct in6_ifaddr *ia6;
/* get the outgoing interface */
if ((*errorp = in6_selectif(dstsock, opts, mopts, ro, &ifp))
!= 0) {
return(NULL);
}
/*
* determine the appropriate zone id of the source based on
* the zone of the destination and the outgoing interface.
*/
bzero(&srcsock, sizeof(srcsock));
srcsock.sin6_family = AF_INET6;
srcsock.sin6_len = sizeof(srcsock);
srcsock.sin6_addr = pi->ipi6_addr;
if (ifp) {
int64_t zone;
zone = in6_addr2zoneid(ifp, &pi->ipi6_addr);
if (zone < 0) { /* XXX: this should not happen */
*errorp = EINVAL;
return(NULL);
}
srcsock.sin6_scope_id = zone;
}
if ((*errorp = in6_embedscope(&srcsock.sin6_addr, &srcsock))
!= 0) {
return(NULL);
}
#ifndef SCOPEDROUTING
srcsock.sin6_scope_id = 0; /* XXX: ifa_ifwithaddr expects 0 */
#endif
ia6 = (struct in6_ifaddr *)ifa_ifwithaddr((struct sockaddr *)(&srcsock));
if (ia6 == NULL ||
(ia6->ia6_flags & (IN6_IFF_ANYCAST | IN6_IFF_NOTREADY))) {
*errorp = EADDRNOTAVAIL;
return(NULL);
}
pi->ipi6_addr = srcsock.sin6_addr; /* XXX: this overrides pi */
if (*ifpp)
*ifpp = ifp;
return(&pi->ipi6_addr);
}
/*
* Otherwise, if the socket has already bound the source, just use it.
*/
if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr))
return(laddr);
/*
* If the address is not specified, choose the best one based on
* the outgoing interface and the destination address.
*/
/* get the outgoing interface */
if ((*errorp = in6_selectif(dstsock, opts, mopts, ro, &ifp)) != 0)
return(NULL);
#ifdef MIP6
#ifdef MIP6_ALLOW_COA_FALLBACK
for (sc = TAILQ_FIRST(&hif_softc_list);
sc;
sc = TAILQ_NEXT(sc, hif_entry)) {
mbu_dst = mip6_bu_list_find_withpaddr(&sc->hif_bu_list, dst);
if (mbu_dst != NULL)
coafallback = mbu_dst->mbu_coafallback;
}
#endif /* MIP6_ALLOW_COA_FALLBACK */
#endif /* MIP6 */
#ifdef DIAGNOSTIC
if (ifp == NULL) /* this should not happen */
panic("in6_selectsrc: NULL ifp");
#endif
for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
int new_scope = -1, new_matchlen = -1;
struct in6_addrpolicy *new_policy = NULL;
int64_t srczone, dstzone;
struct ifnet *ifp1 = ia->ia_ifp;
/*
* We'll never take an address that breaks the scope zone
* of the destination. We also skip an address if its zone
* does not contain the outgoing interface.
* XXX: we should probably use sin6_scope_id here.
*/
if ((dstzone = in6_addr2zoneid(ifp1, dst)) < 0 ||
dstzone != in6_addr2zoneid(ifp, dst)) {
continue;
}
if ((srczone = in6_addr2zoneid(ifp1, &ia->ia_addr.sin6_addr))
< 0 ||
srczone != in6_addr2zoneid(ifp, &ia->ia_addr.sin6_addr)) {
continue;
}
/* avoid unusable addresses */
if ((ia->ia6_flags &
(IN6_IFF_NOTREADY | IN6_IFF_ANYCAST | IN6_IFF_DETACHED))) {
continue;
}
if (!ip6_use_deprecated && IFA6_IS_DEPRECATED(ia))
continue;
/* Rule 1: Prefer same address */
if (IN6_ARE_ADDR_EQUAL(dst, &ia->ia_addr.sin6_addr)) {
ia_best = ia;
BREAK(1); /* there should be no better candidate */
}
if (ia_best == NULL)
REPLACE(0);
/* Rule 2: Prefer appropriate scope */
if (dst_scope < 0)
dst_scope = in6_addrscope(dst);
new_scope = in6_addrscope(&ia->ia_addr.sin6_addr);
if (IN6_ARE_SCOPE_CMP(best_scope, new_scope) < 0) {
if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0)
REPLACE(2);
NEXT(2);
} else if (IN6_ARE_SCOPE_CMP(new_scope, best_scope) < 0) {
if (IN6_ARE_SCOPE_CMP(new_scope, dst_scope) < 0)
NEXT(2);
REPLACE(2);
}
/*
* Rule 3: Avoid deprecated addresses. Note that the case of
* !ip6_use_deprecated is already rejected above.
*/
if (!IFA6_IS_DEPRECATED(ia_best) && IFA6_IS_DEPRECATED(ia))
NEXT(3);
if (IFA6_IS_DEPRECATED(ia_best) && !IFA6_IS_DEPRECATED(ia))
REPLACE(3);
/* Rule 4: Prefer home addresses */
/*
* XXX: This is a TODO. We should probably merge the MIP6
* case above.
*/
#ifdef MIP6
/*
* If SA is simultaneously a home address and care-of address
* and SB is not, then prefer SA. Similarly, if SB is
* simultaneously a home address and care-of address and SA is
* not, then prefer SB.
*/
{
struct mip6_bu *mbu_ia_best = NULL, *mbu_ia = NULL;
if (ia_best->ia6_flags & IN6_IFF_HOME) {
/*
* find a binding update entry for ia_best.
*/
for (sc = TAILQ_FIRST(&hif_softc_list);
sc;
sc = TAILQ_NEXT(sc, hif_entry)) {
mbu_ia_best = mip6_bu_list_find_home_registration(
&sc->hif_bu_list,
&ia->ia_addr.sin6_addr);
if (mbu_ia_best)
break;
}
}
if (ia->ia6_flags & IN6_IFF_HOME) {
/*
* find a binding update entry for ia.
*/
for (sc = TAILQ_FIRST(&hif_softc_list);
sc;
sc = TAILQ_NEXT(sc, hif_entry)) {
mbu_ia = mip6_bu_list_find_home_registration(
&sc->hif_bu_list,
&ia->ia_addr.sin6_addr);
if (mbu_ia)
break;
}
}
/*
* if the binding update entry for a certain address
* exists and its registration status is
* MIP6_BU_REG_STATE_NOTREG, the address is a home
* address and a care of addres simultaneously.
*/
if ((mbu_ia_best &&
(mbu_ia_best->mbu_reg_state
== MIP6_BU_REG_STATE_NOTREG))
&&
!(mbu_ia &&
(mbu_ia->mbu_reg_state
== MIP6_BU_REG_STATE_NOTREG))) {
NEXT(4);
}
if (!(mbu_ia_best &&
(mbu_ia_best->mbu_reg_state
== MIP6_BU_REG_STATE_NOTREG))
&&
(mbu_ia &&
(mbu_ia->mbu_reg_state
== MIP6_BU_REG_STATE_NOTREG))) {
REPLACE(4);
}
}
#ifdef MIP6_ALLOW_COA_FALLBACK
if (coafallback) {
/*
* if the peer doesn't recognize a home
* address destination option, we will use a
* CoA as a source address instead of a home
* address we have registered before. Though
* this behavior may arouse a mip6 beleiver's
* anger, is very useful in the current
* transition period that many hosts don't
* recognize a home address destination
* option...
*/
if ((ia_best->ia6_flags & IN6_IFF_HOME) == 0 &&
(ia->ia6_flags & IN6_IFF_HOME) != 0) {
/* XXX will break stat! */
NEXT(0);
}
if ((ia_best->ia6_flags & IN6_IFF_HOME) != 0 &&
(ia->ia6_flags & IN6_IFF_HOME) == 0) {
/* XXX will break stat! */
REPLACE(0);
}
} else
#endif
{
/*
* If SA is just a home address and SB is just
* a care-of address, then prefer
* SA. Similarly, if SB is just a home address
* and SA is just a care-of address, then
* prefer SB.
*/
if ((ia_best->ia6_flags & IN6_IFF_HOME) != 0 &&
(ia->ia6_flags & IN6_IFF_HOME) == 0) {
NEXT(4);
}
if ((ia_best->ia6_flags & IN6_IFF_HOME) == 0 &&
(ia->ia6_flags & IN6_IFF_HOME) != 0) {
REPLACE(4);
}
}
#endif /* MIP6 */
/* Rule 5: Prefer outgoing interface */
if (ia_best->ia_ifp == ifp && ia->ia_ifp != ifp)
NEXT(5);
if (ia_best->ia_ifp != ifp && ia->ia_ifp == ifp)
REPLACE(5);
/*
* Rule 6: Prefer matching label
* Note that best_policy should be non-NULL here.
*/
if (dst_policy == NULL)
dst_policy = lookup_addrsel_policy(dstsock);
if (dst_policy->label != ADDR_LABEL_NOTAPP) {
new_policy = lookup_addrsel_policy(&ia->ia_addr);
if (dst_policy->label == best_policy->label &&
dst_policy->label != new_policy->label)
NEXT(6);
if (dst_policy->label != best_policy->label &&
dst_policy->label == new_policy->label)
REPLACE(6);
}
/*
* Rule 7: Prefer public addresses.
* We allow users to reverse the logic by configuring
* a sysctl variable, so that privacy conscious users can
* always prefer temporary addresses.
*/
if (!(ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
(ia->ia6_flags & IN6_IFF_TEMPORARY)) {
if (ip6_prefer_tempaddr)
REPLACE(7);
else
NEXT(7);
}
if ((ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
!(ia->ia6_flags & IN6_IFF_TEMPORARY)) {
if (ip6_prefer_tempaddr)
NEXT(7);
else
REPLACE(7);
}
/*
* Rule 8: prefer addresses on alive interfaces.
* This is a KAME specific rule.
*/
if ((ia_best->ia_ifp->if_flags & IFF_UP) &&
!(ia->ia_ifp->if_flags & IFF_UP))
NEXT(8);
if (!(ia_best->ia_ifp->if_flags & IFF_UP) &&
(ia->ia_ifp->if_flags & IFF_UP))
REPLACE(8);
/*
* Rule 9: prefer addresses on "preferred" interfaces.
* This is a KAME specific rule.
*/
#define NDI_BEST (nd_ifinfo[ia_best->ia_ifp->if_index])
#define NDI_NEW (nd_ifinfo[ia->ia_ifp->if_index])
if ((NDI_BEST.flags & ND6_IFF_PREFER_SOURCE) &&
!(NDI_NEW.flags & ND6_IFF_PREFER_SOURCE))
NEXT(9);
if (!(NDI_BEST.flags & ND6_IFF_PREFER_SOURCE) &&
(NDI_NEW.flags & ND6_IFF_PREFER_SOURCE))
REPLACE(9);
#undef NDI_BEST
#undef NDI_NEW
/*
* Rule 14: Use longest matching prefix.
* Note: in the address selection draft, this rule is
* documented as "Rule 8". However, since it is also
* documented that this rule can be overridden, we assign
* a large number so that it is easy to assign smaller numbers
* to more preferred rules.
*/
new_matchlen = in6_matchlen(&ia->ia_addr.sin6_addr, dst);
if (best_matchlen < new_matchlen)
REPLACE(14);
if (new_matchlen < best_matchlen)
NEXT(14);
/* Rule 15 is reserved. */
/*
* Last resort: just keep the current candidate.
* Or, do we need more rules?
*/
continue;
replace:
ia_best = ia;
best_scope = (new_scope >= 0 ? new_scope :
in6_addrscope(&ia_best->ia_addr.sin6_addr));
best_policy = (new_policy ? new_policy :
lookup_addrsel_policy(&ia_best->ia_addr));
best_matchlen = (new_matchlen >= 0 ? new_matchlen :
in6_matchlen(&ia_best->ia_addr.sin6_addr,
dst));
next:
continue;
out:
break;
}
if ((ia = ia_best) == NULL) {
*errorp = EADDRNOTAVAIL;
return(NULL);
}
if (ifpp)
*ifpp = ifp;
return(&ia->ia_addr.sin6_addr);
}
struct in6_addr *
in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
struct inpcb *inp, struct route_in6 *ro,
struct ifnet **ifpp, struct in6_addr *src_storage, unsigned int ifscope,
int *errorp)
{
struct in6_addr dst;
struct ifnet *ifp = NULL;
struct in6_ifaddr *ia = NULL, *ia_best = NULL;
struct in6_pktinfo *pi = NULL;
int dst_scope = -1, best_scope = -1, best_matchlen = -1;
struct in6_addrpolicy *dst_policy = NULL, *best_policy = NULL;
u_int32_t odstzone;
int prefer_tempaddr;
struct ip6_moptions *mopts;
struct timeval timenow;
unsigned int nocell;
boolean_t islocal = FALSE;
getmicrotime(&timenow);
dst = dstsock->sin6_addr; /* make a copy for local operation */
*errorp = 0;
if (ifpp != NULL)
*ifpp = NULL;
if (inp != NULL) {
mopts = inp->in6p_moptions;
nocell = (inp->inp_flags & INP_NO_IFT_CELLULAR) ? 1 : 0;
} else {
mopts = NULL;
nocell = 0;
}
/*
* If the source address is explicitly specified by the caller,
* check if the requested source address is indeed a unicast address
* assigned to the node, and can be used as the packet's source
* address. If everything is okay, use the address as source.
*/
if (opts && (pi = opts->ip6po_pktinfo) &&
!IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) {
struct sockaddr_in6 srcsock;
struct in6_ifaddr *ia6;
/* get the outgoing interface */
if ((*errorp = in6_selectif(dstsock, opts, mopts, ro, ifscope,
nocell, &ifp)) != 0) {
return (NULL);
}
/*
* determine the appropriate zone id of the source based on
* the zone of the destination and the outgoing interface.
* If the specified address is ambiguous wrt the scope zone,
* the interface must be specified; otherwise, ifa_ifwithaddr()
* will fail matching the address.
*/
bzero(&srcsock, sizeof(srcsock));
srcsock.sin6_family = AF_INET6;
srcsock.sin6_len = sizeof(srcsock);
srcsock.sin6_addr = pi->ipi6_addr;
if (ifp) {
*errorp = in6_setscope(&srcsock.sin6_addr, ifp, NULL);
if (*errorp != 0) {
ifnet_release(ifp);
return (NULL);
}
}
ia6 = (struct in6_ifaddr *)ifa_ifwithaddr((struct sockaddr *)(&srcsock));
if (ia6 == NULL) {
*errorp = EADDRNOTAVAIL;
if (ifp != NULL)
ifnet_release(ifp);
return (NULL);
}
IFA_LOCK_SPIN(&ia6->ia_ifa);
if ((ia6->ia6_flags & (IN6_IFF_ANYCAST | IN6_IFF_NOTREADY)) ||
(nocell && (ia6->ia_ifa.ifa_ifp->if_type == IFT_CELLULAR))) {
IFA_UNLOCK(&ia6->ia_ifa);
IFA_REMREF(&ia6->ia_ifa);
*errorp = EADDRNOTAVAIL;
if (ifp != NULL)
ifnet_release(ifp);
return (NULL);
}
*src_storage = satosin6(&ia6->ia_addr)->sin6_addr;
IFA_UNLOCK(&ia6->ia_ifa);
IFA_REMREF(&ia6->ia_ifa);
if (ifpp != NULL) {
/* if ifp is non-NULL, refcnt held in in6_selectif() */
*ifpp = ifp;
} else if (ifp != NULL) {
ifnet_release(ifp);
}
return (src_storage);
}
/*
* Otherwise, if the socket has already bound the source, just use it.
*/
if (inp != NULL && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr))
return (&inp->in6p_laddr);
/*
* If the address is not specified, choose the best one based on
* the outgoing interface and the destination address.
*/
/* get the outgoing interface */
if ((*errorp = in6_selectif(dstsock, opts, mopts, ro, ifscope, nocell,
&ifp)) != 0)
return (NULL);
#ifdef DIAGNOSTIC
if (ifp == NULL) /* this should not happen */
panic("in6_selectsrc: NULL ifp");
#endif
*errorp = in6_setscope(&dst, ifp, &odstzone);
if (*errorp != 0) {
if (ifp != NULL)
ifnet_release(ifp);
return (NULL);
}
lck_rw_lock_shared(&in6_ifaddr_rwlock);
for (ia = in6_ifaddrs; ia; ia = ia->ia_next) {
int new_scope = -1, new_matchlen = -1;
struct in6_addrpolicy *new_policy = NULL;
u_int32_t srczone, osrczone, dstzone;
struct in6_addr src;
struct ifnet *ifp1 = ia->ia_ifp;
IFA_LOCK(&ia->ia_ifa);
/*
* We'll never take an address that breaks the scope zone
* of the destination. We also skip an address if its zone
* does not contain the outgoing interface.
* XXX: we should probably use sin6_scope_id here.
*/
if (in6_setscope(&dst, ifp1, &dstzone) ||
odstzone != dstzone)
goto next;
src = ia->ia_addr.sin6_addr;
if (in6_setscope(&src, ifp, &osrczone) ||
in6_setscope(&src, ifp1, &srczone) ||
osrczone != srczone)
goto next;
/* avoid unusable addresses */
if ((ia->ia6_flags &
(IN6_IFF_NOTREADY | IN6_IFF_ANYCAST | IN6_IFF_DETACHED)))
goto next;
if (!ip6_use_deprecated && IFA6_IS_DEPRECATED(ia))
goto next;
/* Rule 1: Prefer same address */
if (IN6_ARE_ADDR_EQUAL(&dst, &ia->ia_addr.sin6_addr))
BREAK(1); /* there should be no better candidate */
if (ia_best == NULL)
REPLACE(0);
/* Rule 2: Prefer appropriate scope */
if (dst_scope < 0)
dst_scope = in6_addrscope(&dst);
new_scope = in6_addrscope(&ia->ia_addr.sin6_addr);
if (IN6_ARE_SCOPE_CMP(best_scope, new_scope) < 0) {
if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0)
REPLACE(2);
NEXTSRC(2);
} else if (IN6_ARE_SCOPE_CMP(new_scope, best_scope) < 0) {
if (IN6_ARE_SCOPE_CMP(new_scope, dst_scope) < 0)
NEXTSRC(2);
REPLACE(2);
}
/*
* Rule 3: Avoid deprecated addresses. Note that the case of
* !ip6_use_deprecated is already rejected above.
*/
if (!IFA6_IS_DEPRECATED(ia_best) && IFA6_IS_DEPRECATED(ia))
NEXTSRC(3);
if (IFA6_IS_DEPRECATED(ia_best) && !IFA6_IS_DEPRECATED(ia))
REPLACE(3);
/* Rule 4: Prefer home addresses */
/*
* XXX: This is a TODO. We should probably merge the MIP6
* case above.
*/
/* Rule 5: Prefer outgoing interface */
if (ia_best->ia_ifp == ifp && ia->ia_ifp != ifp)
NEXTSRC(5);
if (ia_best->ia_ifp != ifp && ia->ia_ifp == ifp)
REPLACE(5);
/*
* Rule 6: Prefer matching label
* Note that best_policy should be non-NULL here.
*/
if (dst_policy == NULL)
dst_policy = in6_addrsel_lookup_policy(dstsock);
if (dst_policy->label != ADDR_LABEL_NOTAPP) {
new_policy = in6_addrsel_lookup_policy(&ia->ia_addr);
if (dst_policy->label == best_policy->label &&
dst_policy->label != new_policy->label)
NEXTSRC(6);
if (dst_policy->label != best_policy->label &&
dst_policy->label == new_policy->label)
REPLACE(6);
}
/*
* Rule 7: Prefer public addresses.
* We allow users to reverse the logic by configuring
* a sysctl variable, so that privacy conscious users can
* always prefer temporary addresses.
* Don't use temporary addresses for local destinations or
* for multicast addresses unless we were passed in an option.
*/
if (IN6_IS_ADDR_MULTICAST(&dst) ||
in6_matchlen(&ia_best->ia_addr.sin6_addr, &dst) >=
in6_mask2len(&ia_best->ia_prefixmask.sin6_addr, NULL))
islocal = TRUE;
if (opts == NULL ||
opts->ip6po_prefer_tempaddr == IP6PO_TEMPADDR_SYSTEM) {
prefer_tempaddr = islocal ? 0 : ip6_prefer_tempaddr;
} else if (opts->ip6po_prefer_tempaddr ==
IP6PO_TEMPADDR_NOTPREFER) {
prefer_tempaddr = 0;
} else
prefer_tempaddr = 1;
if (!(ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
(ia->ia6_flags & IN6_IFF_TEMPORARY)) {
if (prefer_tempaddr)
REPLACE(7);
else
NEXTSRC(7);
}
if ((ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
!(ia->ia6_flags & IN6_IFF_TEMPORARY)) {
if (prefer_tempaddr)
NEXTSRC(7);
else
REPLACE(7);
}
/*
* Rule 8: prefer addresses on alive interfaces.
* This is a KAME specific rule.
*/
if ((ia_best->ia_ifp->if_flags & IFF_UP) &&
!(ia->ia_ifp->if_flags & IFF_UP))
NEXTSRC(8);
if (!(ia_best->ia_ifp->if_flags & IFF_UP) &&
(ia->ia_ifp->if_flags & IFF_UP))
REPLACE(8);
/*
* Rule 14: Use longest matching prefix.
* Note: in the address selection draft, this rule is
* documented as "Rule 8". However, since it is also
* documented that this rule can be overridden, we assign
* a large number so that it is easy to assign smaller numbers
* to more preferred rules.
*/
new_matchlen = in6_matchlen(&ia->ia_addr.sin6_addr, &dst);
if (best_matchlen < new_matchlen)
REPLACE(14);
if (new_matchlen < best_matchlen)
NEXTSRC(14);
/* Rule 15 is reserved. */
/*
* Last resort: just keep the current candidate.
* Or, do we need more rules?
*/
IFA_UNLOCK(&ia->ia_ifa);
continue;
replace:
best_scope = (new_scope >= 0 ? new_scope :
in6_addrscope(&ia->ia_addr.sin6_addr));
best_policy = (new_policy ? new_policy :
in6_addrsel_lookup_policy(&ia->ia_addr));
best_matchlen = (new_matchlen >= 0 ? new_matchlen :
in6_matchlen(&ia->ia_addr.sin6_addr, &dst));
IFA_ADDREF_LOCKED(&ia->ia_ifa); /* for ia_best */
IFA_UNLOCK(&ia->ia_ifa);
if (ia_best != NULL)
IFA_REMREF(&ia_best->ia_ifa);
ia_best = ia;
continue;
next:
IFA_UNLOCK(&ia->ia_ifa);
continue;
out:
IFA_ADDREF_LOCKED(&ia->ia_ifa); /* for ia_best */
IFA_UNLOCK(&ia->ia_ifa);
if (ia_best != NULL)
IFA_REMREF(&ia_best->ia_ifa);
ia_best = ia;
break;
}
lck_rw_done(&in6_ifaddr_rwlock);
if (nocell && ia_best != NULL &&
(ia_best->ia_ifa.ifa_ifp->if_type == IFT_CELLULAR)) {
IFA_REMREF(&ia_best->ia_ifa);
ia_best = NULL;
}
if ( (ia = ia_best) == NULL) {
*errorp = EADDRNOTAVAIL;
if (ifp != NULL)
ifnet_release(ifp);
return (NULL);
}
IFA_LOCK_SPIN(&ia->ia_ifa);
*src_storage = satosin6(&ia->ia_addr)->sin6_addr;
IFA_UNLOCK(&ia->ia_ifa);
IFA_REMREF(&ia->ia_ifa);
if (ifpp != NULL) {
/* if ifp is non-NULL, refcnt held in in6_selectif() */
*ifpp = ifp;
} else if (ifp != NULL) {
ifnet_release(ifp);
}
return (src_storage);
}
/*
* Return an IPv6 address, which is the most appropriate for a given
* destination and user specified options.
* If necessary, this function lookups the routing table and returns
* an entry to the caller for later use.
*/
int
in6_selectsrc(struct in6_addr **in6src, struct sockaddr_in6 *dstsock,
struct ip6_pktopts *opts, struct ip6_moptions *mopts,
struct route_in6 *ro, struct in6_addr *laddr, u_int rtableid)
{
struct ifnet *ifp = NULL;
struct in6_addr *dst;
struct in6_ifaddr *ia6 = NULL;
struct in6_pktinfo *pi = NULL;
int error;
dst = &dstsock->sin6_addr;
/*
* If the source address is explicitly specified by the caller,
* check if the requested source address is indeed a unicast address
* assigned to the node, and can be used as the packet's source
* address. If everything is okay, use the address as source.
*/
if (opts && (pi = opts->ip6po_pktinfo) &&
!IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) {
struct sockaddr_in6 sa6;
/* get the outgoing interface */
error = in6_selectif(dstsock, opts, mopts, ro, &ifp, rtableid);
if (error)
return (error);
bzero(&sa6, sizeof(sa6));
sa6.sin6_family = AF_INET6;
sa6.sin6_len = sizeof(sa6);
sa6.sin6_addr = pi->ipi6_addr;
if (ifp && IN6_IS_SCOPE_EMBED(&sa6.sin6_addr))
sa6.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
if_put(ifp); /* put reference from in6_selectif */
ia6 = ifatoia6(ifa_ifwithaddr(sin6tosa(&sa6), rtableid));
if (ia6 == NULL ||
(ia6->ia6_flags & (IN6_IFF_ANYCAST | IN6_IFF_NOTREADY)))
return (EADDRNOTAVAIL);
pi->ipi6_addr = sa6.sin6_addr; /* XXX: this overrides pi */
*in6src = &pi->ipi6_addr;
return (0);
}
/*
* If the source address is not specified but the socket(if any)
* is already bound, use the bound address.
*/
if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr)) {
*in6src = laddr;
return (0);
}
/*
* If the caller doesn't specify the source address but
* the outgoing interface, use an address associated with
* the interface.
*/
if (pi && pi->ipi6_ifindex) {
ifp = if_get(pi->ipi6_ifindex);
if (ifp == NULL)
return (ENXIO); /* XXX: better error? */
ia6 = in6_ifawithscope(ifp, dst, rtableid);
if_put(ifp);
if (ia6 == NULL)
return (EADDRNOTAVAIL);
*in6src = &ia6->ia_addr.sin6_addr;
return (0);
}
/*
* If the destination address is a link-local unicast address or
* a link/interface-local multicast address, and if the outgoing
* interface is specified by the sin6_scope_id filed, use an address
* associated with the interface.
* XXX: We're now trying to define more specific semantics of
* sin6_scope_id field, so this part will be rewritten in
* the near future.
*/
if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MC_LINKLOCAL(dst) ||
IN6_IS_ADDR_MC_INTFACELOCAL(dst)) && dstsock->sin6_scope_id) {
ifp = if_get(dstsock->sin6_scope_id);
if (ifp == NULL)
return (ENXIO); /* XXX: better error? */
ia6 = in6_ifawithscope(ifp, dst, rtableid);
if_put(ifp);
if (ia6 == NULL)
return (EADDRNOTAVAIL);
*in6src = &ia6->ia_addr.sin6_addr;
return (0);
}
/*
* If the destination address is a multicast address and
* the outgoing interface for the address is specified
* by the caller, use an address associated with the interface.
* Even if the outgoing interface is not specified, we also
* choose a loopback interface as the outgoing interface.
*/
if (IN6_IS_ADDR_MULTICAST(dst)) {
ifp = mopts ? if_get(mopts->im6o_ifidx) : NULL;
if (!ifp && dstsock->sin6_scope_id)
ifp = if_get(htons(dstsock->sin6_scope_id));
if (ifp) {
ia6 = in6_ifawithscope(ifp, dst, rtableid);
if_put(ifp);
if (ia6 == NULL)
return (EADDRNOTAVAIL);
*in6src = &ia6->ia_addr.sin6_addr;
return (0);
}
}
/*
* If route is known or can be allocated now,
* our src addr is taken from the i/f, else punt.
*/
if (ro) {
if (!rtisvalid(ro->ro_rt) || (ro->ro_tableid != rtableid) ||
!IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, dst)) {
rtfree(ro->ro_rt);
ro->ro_rt = NULL;
}
if (ro->ro_rt == NULL) {
struct sockaddr_in6 *sa6;
/* No route yet, so try to acquire one */
bzero(&ro->ro_dst, sizeof(struct sockaddr_in6));
ro->ro_tableid = rtableid;
sa6 = &ro->ro_dst;
sa6->sin6_family = AF_INET6;
sa6->sin6_len = sizeof(struct sockaddr_in6);
sa6->sin6_addr = *dst;
sa6->sin6_scope_id = dstsock->sin6_scope_id;
ro->ro_rt = rtalloc(sin6tosa(&ro->ro_dst),
RT_RESOLVE, ro->ro_tableid);
}
/*
* in_pcbconnect() checks out IFF_LOOPBACK to skip using
* the address. But we don't know why it does so.
* It is necessary to ensure the scope even for lo0
* so doesn't check out IFF_LOOPBACK.
*/
if (ro->ro_rt) {
ifp = if_get(ro->ro_rt->rt_ifidx);
if (ifp != NULL) {
ia6 = in6_ifawithscope(ifp, dst, rtableid);
if_put(ifp);
}
if (ia6 == NULL) /* xxx scope error ?*/
ia6 = ifatoia6(ro->ro_rt->rt_ifa);
}
if (ia6 == NULL)
return (EHOSTUNREACH); /* no route */
*in6src = &ia6->ia_addr.sin6_addr;
return (0);
}
return (EADDRNOTAVAIL);
}
