in6_src.c

来自「eCos操作系统源码」· C语言 代码 · 共 1,336 行 · 第 1/3 页

			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);
}
#undef REPLACE
#undef BREAK
#undef NEXT

static int
in6_selectif(dstsock, opts, mopts, ro, retifp)
	struct sockaddr_in6 *dstsock;
	struct ip6_pktopts *opts;
	struct ip6_moptions *mopts;
#ifdef NEW_STRUCT_ROUTE
	struct route *ro;
#else
	struct route_in6 *ro;
#endif
	struct ifnet **retifp;
{
	int error, clone;
	struct rtentry *rt = NULL;

	clone = IN6_IS_ADDR_MULTICAST(&dstsock->sin6_addr) ? 0 : 1;
	if ((error = in6_selectroute(dstsock, opts, mopts, ro, retifp,
				     &rt, clone)) != 0) {
		return(error);
	}
	/*
	 * Adjust the "outgoing" interface.  If we're going to loop the packet
	 * back to ourselves, the ifp would be the loopback interface.
	 * However, we'd rather know the interface associated to the
	 * destination address (which should probably be one of our own
	 * addresses.)
	 */
	if (rt && rt->rt_ifa && rt->rt_ifa->ifa_ifp)
		*retifp = rt->rt_ifa->ifa_ifp;

	return(0);
}

int
in6_selectroute(dstsock, opts, mopts, ro, retifp, retrt, clone)
	struct sockaddr_in6 *dstsock;
	struct ip6_pktopts *opts;
	struct ip6_moptions *mopts;
#ifdef NEW_STRUCT_ROUTE
	struct route *ro;
#else
	struct route_in6 *ro;
#endif
	struct ifnet **retifp;
	struct rtentry **retrt;
	int clone;		/* meaningful only for bsdi and freebsd. */
{
	int error = 0;
	struct ifnet *ifp = NULL;
	struct rtentry *rt = NULL;
	struct sockaddr_in6 *sin6_next;
	struct in6_pktinfo *pi = NULL;
	struct in6_addr *dst = &dstsock->sin6_addr;

	/* If the caller specify the outgoing interface explicitly, use it. */
	if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) {
		/* XXX boundary check is assumed to be already done. */
#if defined(__FreeBSD__) && __FreeBSD__ >= 5
		ifp = ifnet_byindex(pi->ipi6_ifindex);
#else
		ifp = ifindex2ifnet[pi->ipi6_ifindex];
#endif
		if (ifp != NULL &&
		    (retrt == NULL || IN6_IS_ADDR_MULTICAST(dst))) {
			/*
			 * we do not have to check nor get the route for
			 * multicast.
			 */
			goto done;
		} else
			goto getroute;
	}

	/*
	 * If the destination address is a multicast address and the outgoing
	 * interface for the address is specified by the caller, use it.
	 */
	if (IN6_IS_ADDR_MULTICAST(dst) &&
	    mopts != NULL && (ifp = mopts->im6o_multicast_ifp) != NULL) {
		goto done; /* we do not need a route for multicast. */
	}

  getroute:
	/*
	 * If the next hop address for the packet is specified by the caller,
	 * use it as the gateway.
	 */
	if (opts && opts->ip6po_nexthop) {
#ifdef NEW_STRUCT_ROUTE
		struct route *ron;
#else
		struct route_in6 *ron;
#endif

		sin6_next = satosin6(opts->ip6po_nexthop);

		/* at this moment, we only support AF_INET6 next hops */
		if (sin6_next->sin6_family != AF_INET6) {
			error = EAFNOSUPPORT; /* or should we proceed? */
			goto done;
		}

		/*
		 * If the next hop is an IPv6 address, then the node identified
		 * by that address must be a neighbor of the sending host.
		 */
		ron = &opts->ip6po_nextroute;
		if ((ron->ro_rt &&
		     (ron->ro_rt->rt_flags & (RTF_UP | RTF_LLINFO)) !=
		     (RTF_UP | RTF_LLINFO)) ||
		    !SA6_ARE_ADDR_EQUAL(satosin6(&ron->ro_dst), sin6_next)) {
			if (ron->ro_rt) {
				RTFREE(ron->ro_rt);
				ron->ro_rt = NULL;
			}
			*satosin6(&ron->ro_dst) = *sin6_next;
		}
		if (ron->ro_rt == NULL) {
			rtalloc((struct route *)ron); /* multi path case? */
			if (ron->ro_rt == NULL ||
			    !(ron->ro_rt->rt_flags & RTF_LLINFO)) {
				if (ron->ro_rt) {
					RTFREE(ron->ro_rt);
					ron->ro_rt = NULL;
				}
				error = EHOSTUNREACH;
				goto done;
			}
		}
		rt = ron->ro_rt;
		ifp = rt->rt_ifp;

		/*
		 * When cloning is required, try to allocate a route to the
		 * destination so that the caller can store path MTU
		 * information.
		 */
		if (!clone)
			goto done;
	}

	/*
	 * Use a cached route if it exists and is valid, else try to allocate
	 * a new one.
	 */
	if (ro) {
		int newroute = 0;

		if (ro->ro_rt &&
		    (!(ro->ro_rt->rt_flags & RTF_UP) ||
		     !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr,
					dst))) {
			RTFREE(ro->ro_rt);
			ro->ro_rt = (struct rtentry *)NULL;
		}
		if (ro->ro_rt == (struct rtentry *)NULL) {
			struct sockaddr_in6 *sa6;

			/* No route yet, so try to acquire one */
			newroute = 1;
			bzero(&ro->ro_dst, sizeof(struct sockaddr_in6));
			sa6 = (struct sockaddr_in6 *)&ro->ro_dst;
			sa6->sin6_family = AF_INET6;
			sa6->sin6_len = sizeof(struct sockaddr_in6);
			sa6->sin6_addr = *dst;
#ifdef SCOPEDROUTING
			sa6->sin6_scope_id = dstsock->sin6_scope_id;
#endif
			if (clone) {
#ifdef __bsdi__
				rtcalloc((struct route *)ro);
#else  /* !bsdi */
#ifdef RADIX_MPATH
				rtalloc_mpath((struct route *)ro,
				    ntohl(dstsock->sin6_addr.s6_addr32[3]));
#else
				rtalloc((struct route *)ro);
#endif /* RADIX_MPATH */
#endif /* bsdi */
			} else {
#ifdef __FreeBSD__
				ro->ro_rt = rtalloc1(&((struct route *)ro)
						     ->ro_dst, (int)NULL, 0UL);
#else
#ifdef RADIX_MPATH
				rtalloc_mpath((struct route *)ro,
				    ntohl(dstsock->sin6_addr.s6_addr32[3]));
#else
				ro->ro_rt = rtalloc1(&((struct route *)ro)
						     ->ro_dst, NULL);
#endif /* RADIX_MPATH */
#endif /* __FreeBSD__ */
			}
		}

		/*
		 * do not care about the result if we have the nexthop
		 * explicitly specified.
		 */
		if (opts && opts->ip6po_nexthop)
			goto done;

		if (ro->ro_rt) {
			ifp = ro->ro_rt->rt_ifp;

			if (ifp == NULL) { /* can this really happen? */
				RTFREE(ro->ro_rt);
				ro->ro_rt = NULL;
			}
		}
		if (ro->ro_rt == NULL)
			error = EHOSTUNREACH;
		rt = ro->ro_rt;

		/*
		 * Check if the outgoing interface conflicts with
		 * the interface specified by ipi6_ifindex (if specified).
		 * Note that loopback interface is always okay.
		 * (this may happen when we are sending a packet to one of
		 *  our own addresses.)
		 */
		if (opts && opts->ip6po_pktinfo
		    && opts->ip6po_pktinfo->ipi6_ifindex) {
			if (!(ifp->if_flags & IFF_LOOPBACK) &&
			    ifp->if_index !=
			    opts->ip6po_pktinfo->ipi6_ifindex) {
				error = EHOSTUNREACH;
				goto done;
			}
		}
	}

  done:
	if (error == EHOSTUNREACH)
		ip6stat.ip6s_noroute++;

	if (retifp != NULL)
		*retifp = ifp;
	if (retrt != NULL)
		*retrt = rt;	/* rt may be NULL */
	
	return(error);
}

/*
 * Default hop limit selection. The precedence is as follows:
 * 1. Hoplimit value specified via ioctl.
 * 2. (If the outgoing interface is detected) the current
 *     hop limit of the interface specified by router advertisement.
 * 3. The system default hoplimit.
*/
#ifdef HAVE_NRL_INPCB
#define in6pcb		inpcb
#define in6p_hops	inp_hops	
#endif
int
in6_selecthlim(struct in6pcb *in6p, struct ifnet *ifp)
{
	if (in6p && in6p->in6p_hops >= 0)
		return(in6p->in6p_hops);
	else if (ifp)
		return(nd_ifinfo[ifp->if_index].chlim);
	else
		return(ip6_defhlim);
}
#ifdef HAVE_NRL_INPCB
#undef in6pcb
#undef in6p_hops
#endif

#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3) && !defined(__OpenBSD__)
/*
 * Find an empty port and set it to the specified PCB.
 */
#ifdef HAVE_NRL_INPCB	/* XXX: I really hate such ugly macros...(jinmei) */
#define in6pcb		inpcb
#define in6p_socket	inp_socket
#define in6p_lport	inp_lport
#define in6p_head	inp_head
#define in6p_flags	inp_flags
#define IN6PLOOKUP_WILDCARD INPLOOKUP_WILDCARD
#endif
int
in6_pcbsetport(struct in6_addr *laddr, struct in6pcb *in6p)
{
	struct socket *so = in6p->in6p_socket;
	struct in6pcb *head = in6p->in6p_head;
	u_int16_t last_port, lport = 0;
	int wild = 0;
	void *t;
	u_int16_t min, max;

	/* XXX: this is redundant when called from in6_pcbbind */
	if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) == 0 &&
	   ((so->so_proto->pr_flags & PR_CONNREQUIRED) == 0 ||
	    (so->so_options & SO_ACCEPTCONN) == 0))
		wild = IN6PLOOKUP_WILDCARD;

	if (in6p->in6p_flags & IN6P_LOWPORT) {
		min = ip6_lowportmin;
		max = ip6_lowportmax;
	} else {
		min = ip6_anonportmin;
		max = ip6_anonportmax;
	}

	/* value out of range */
	if (head->in6p_lport < min)
		head->in6p_lport = min;
	else if (head->in6p_lport > max)
		head->in6p_lport = min;
	last_port = head->in6p_lport;
	goto startover;	/*to randomize*/
	for (;;) {
		lport = htons(head->in6p_lport);
		if (IN6_IS_ADDR_V4MAPPED(laddr)) {
#ifdef HAVE_NRL_INPCB
#ifdef INPLOOKUP_WILDCARD6