339 lines
8.5 KiB
C
339 lines
8.5 KiB
C
/* $KAME: radix_mpath.c,v 1.17 2004/11/08 10:29:39 itojun Exp $ */
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/*
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* Copyright (C) 2001 WIDE Project.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the project nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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* THE AUTHORS DO NOT GUARANTEE THAT THIS SOFTWARE DOES NOT INFRINGE
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* ANY OTHERS' INTELLECTUAL PROPERTIES. IN NO EVENT SHALL THE AUTHORS
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* BE LIABLE FOR ANY INFRINGEMENT OF ANY OTHERS' INTELLECTUAL
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* PROPERTIES.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_inet6.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/socket.h>
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#include <sys/domain.h>
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#include <sys/syslog.h>
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#include <net/radix.h>
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#include <net/radix_mpath.h>
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#include <net/route.h>
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#include <net/if.h>
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#include <net/if_var.h>
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/*
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* give some jitter to hash, to avoid synchronization between routers
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*/
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static u_int32_t hashjitter;
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int
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rn_mpath_capable(struct radix_node_head *rnh)
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{
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return rnh->rnh_multipath;
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}
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struct radix_node *
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rn_mpath_next(struct radix_node *rn)
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{
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struct radix_node *next;
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if (!rn->rn_dupedkey)
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return NULL;
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next = rn->rn_dupedkey;
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if (rn->rn_mask == next->rn_mask)
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return next;
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else
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return NULL;
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}
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int
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rn_mpath_count(struct radix_node *rn)
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{
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int i;
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i = 1;
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while ((rn = rn_mpath_next(rn)) != NULL)
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i++;
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return i;
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}
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struct rtentry *
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rt_mpath_matchgate(struct rtentry *rt, struct sockaddr *gate)
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{
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struct radix_node *rn;
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if (!rn_mpath_next((struct radix_node *)rt))
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return rt;
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if (!gate)
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return NULL;
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/* beyond here, we use rn as the master copy */
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rn = (struct radix_node *)rt;
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do {
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rt = (struct rtentry *)rn;
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/*
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* we are removing an address alias that has
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* the same prefix as another address
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* we need to compare the interface address because
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* rt_gateway is a special sockadd_dl structure
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*/
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if (rt->rt_gateway->sa_family == AF_LINK) {
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if (!memcmp(rt->rt_ifa->ifa_addr, gate, gate->sa_len))
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break;
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} else {
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if (rt->rt_gateway->sa_len == gate->sa_len &&
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!memcmp(rt->rt_gateway, gate, gate->sa_len))
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break;
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}
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} while ((rn = rn_mpath_next(rn)) != NULL);
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return (struct rtentry *)rn;
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}
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/*
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* go through the chain and unlink "rt" from the list
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* the caller will free "rt"
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*/
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int
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rt_mpath_deldup(struct rtentry *headrt, struct rtentry *rt)
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{
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struct radix_node *t, *tt;
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if (!headrt || !rt)
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return (0);
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t = (struct radix_node *)headrt;
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tt = rn_mpath_next(t);
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while (tt) {
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if (tt == (struct radix_node *)rt) {
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t->rn_dupedkey = tt->rn_dupedkey;
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tt->rn_dupedkey = NULL;
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tt->rn_flags &= ~RNF_ACTIVE;
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tt[1].rn_flags &= ~RNF_ACTIVE;
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return (1);
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}
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t = tt;
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tt = rn_mpath_next((struct radix_node *)t);
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}
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return (0);
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}
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/*
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* check if we have the same key/mask/gateway on the table already.
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*/
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int
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rt_mpath_conflict(struct radix_node_head *rnh, struct rtentry *rt,
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struct sockaddr *netmask)
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{
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struct radix_node *rn, *rn1;
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struct rtentry *rt1;
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char *p, *q, *eq;
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int same, l, skip;
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rn = (struct radix_node *)rt;
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rn1 = rnh->rnh_lookup(rt_key(rt), netmask, rnh);
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if (!rn1 || rn1->rn_flags & RNF_ROOT)
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return 0;
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/*
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* unlike other functions we have in this file, we have to check
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* all key/mask/gateway as rnh_lookup can match less specific entry.
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*/
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rt1 = (struct rtentry *)rn1;
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/* compare key. */
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if (rt_key(rt1)->sa_len != rt_key(rt)->sa_len ||
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bcmp(rt_key(rt1), rt_key(rt), rt_key(rt1)->sa_len))
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goto different;
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/* key was the same. compare netmask. hairy... */
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if (rt_mask(rt1) && netmask) {
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skip = rnh->rnh_treetop->rn_offset;
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if (rt_mask(rt1)->sa_len > netmask->sa_len) {
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/*
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* as rt_mask(rt1) is made optimal by radix.c,
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* there must be some 1-bits on rt_mask(rt1)
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* after netmask->sa_len. therefore, in
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* this case, the entries are different.
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*/
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if (rt_mask(rt1)->sa_len > skip)
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goto different;
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else {
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/* no bits to compare, i.e. same*/
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goto maskmatched;
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}
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}
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l = rt_mask(rt1)->sa_len;
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if (skip > l) {
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/* no bits to compare, i.e. same */
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goto maskmatched;
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}
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p = (char *)rt_mask(rt1);
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q = (char *)netmask;
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if (bcmp(p + skip, q + skip, l - skip))
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goto different;
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/*
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* need to go through all the bit, as netmask is not
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* optimal and can contain trailing 0s
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*/
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eq = (char *)netmask + netmask->sa_len;
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q += l;
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same = 1;
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while (eq > q)
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if (*q++) {
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same = 0;
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break;
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}
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if (!same)
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goto different;
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} else if (!rt_mask(rt1) && !netmask)
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; /* no mask to compare, i.e. same */
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else {
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/* one has mask and the other does not, different */
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goto different;
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}
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maskmatched:
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/* key/mask were the same. compare gateway for all multipaths */
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do {
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rt1 = (struct rtentry *)rn1;
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/* sanity: no use in comparing the same thing */
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if (rn1 == rn)
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continue;
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if (rt1->rt_gateway->sa_family == AF_LINK) {
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if (rt1->rt_ifa->ifa_addr->sa_len != rt->rt_ifa->ifa_addr->sa_len ||
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bcmp(rt1->rt_ifa->ifa_addr, rt->rt_ifa->ifa_addr,
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rt1->rt_ifa->ifa_addr->sa_len))
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continue;
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} else {
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if (rt1->rt_gateway->sa_len != rt->rt_gateway->sa_len ||
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bcmp(rt1->rt_gateway, rt->rt_gateway,
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rt1->rt_gateway->sa_len))
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continue;
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}
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/* all key/mask/gateway are the same. conflicting entry. */
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return EEXIST;
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} while ((rn1 = rn_mpath_next(rn1)) != NULL);
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different:
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return 0;
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}
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void
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rtalloc_mpath(struct route *ro, int hash)
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{
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struct radix_node *rn0, *rn;
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int n;
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/*
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* XXX we don't attempt to lookup cached route again; what should
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* be done for sendto(3) case?
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*/
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if (ro->ro_rt && ro->ro_rt->rt_ifp && (ro->ro_rt->rt_flags & RTF_UP))
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return; /* XXX */
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ro->ro_rt = rtalloc1(&ro->ro_dst, 1, 0UL);
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/* if the route does not exist or it is not multipath, don't care */
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if (!ro->ro_rt || !rn_mpath_next((struct radix_node *)ro->ro_rt)) {
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RT_UNLOCK(ro->ro_rt);
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return;
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}
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/* beyond here, we use rn as the master copy */
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rn0 = rn = (struct radix_node *)ro->ro_rt;
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n = rn_mpath_count(rn0);
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/* gw selection by Modulo-N Hash (RFC2991) XXX need improvement? */
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hash += hashjitter;
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hash %= n;
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while (hash-- > 0 && rn) {
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/* stay within the multipath routes */
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if (rn->rn_dupedkey && rn->rn_mask != rn->rn_dupedkey->rn_mask)
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break;
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rn = rn->rn_dupedkey;
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}
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/* XXX try filling rt_gwroute and avoid unreachable gw */
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/* if gw selection fails, use the first match (default) */
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if (!rn) {
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RT_UNLOCK(ro->ro_rt);
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return;
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}
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rtfree(ro->ro_rt);
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ro->ro_rt = (struct rtentry *)rn;
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RT_LOCK(ro->ro_rt);
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RT_ADDREF(ro->ro_rt);
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RT_UNLOCK(ro->ro_rt);
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}
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extern int in6_inithead(void **head, int off);
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extern int in_inithead(void **head, int off);
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int
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rn4_mpath_inithead(void **head, int off)
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{
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struct radix_node_head *rnh;
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hashjitter = arc4random();
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if (in_inithead(head, off) == 1) {
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rnh = (struct radix_node_head *)*head;
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rnh->rnh_multipath = 1;
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return 1;
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} else
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return 0;
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}
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#ifdef INET6
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int
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rn6_mpath_inithead(void **head, int off)
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{
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struct radix_node_head *rnh;
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hashjitter = arc4random();
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if (in6_inithead(head, off) == 1) {
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rnh = (struct radix_node_head *)*head;
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rnh->rnh_multipath = 1;
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return 1;
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} else
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return 0;
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}
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#endif
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