6bccea7c2b
PR: bin/154928 Submitted by: Eitan Adler <lists at eitanadler.com> MFC after: 3 days
912 lines
25 KiB
C
912 lines
25 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1988, 1993
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* The Regents of the University of California. 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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* 4. Neither the name of the University 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 REGENTS 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 REGENTS 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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*
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* @(#)if_ether.c 8.1 (Berkeley) 6/10/93
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*/
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/*
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* Ethernet address resolution protocol.
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* TODO:
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* add "inuse/lock" bit (or ref. count) along with valid bit
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_inet.h"
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/queue.h>
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#include <sys/sysctl.h>
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#include <sys/systm.h>
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#include <sys/mbuf.h>
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#include <sys/malloc.h>
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#include <sys/proc.h>
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#include <sys/socket.h>
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#include <sys/syslog.h>
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#include <net/if.h>
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#include <net/if_dl.h>
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#include <net/if_types.h>
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#include <net/netisr.h>
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#include <net/if_llc.h>
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#include <net/ethernet.h>
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#include <net/route.h>
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#include <net/vnet.h>
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#include <netinet/in.h>
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#include <netinet/in_var.h>
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#include <net/if_llatbl.h>
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#include <netinet/if_ether.h>
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#if defined(INET) || defined(INET6)
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#include <netinet/ip_carp.h>
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#endif
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#include <net/if_arc.h>
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#include <net/iso88025.h>
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#include <security/mac/mac_framework.h>
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#define SIN(s) ((struct sockaddr_in *)s)
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#define SDL(s) ((struct sockaddr_dl *)s)
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SYSCTL_DECL(_net_link_ether);
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SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
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SYSCTL_NODE(_net_link_ether, PF_ARP, arp, CTLFLAG_RW, 0, "");
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/* timer values */
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static VNET_DEFINE(int, arpt_keep) = (20*60); /* once resolved, good for 20
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* minutes */
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static VNET_DEFINE(int, arp_maxtries) = 5;
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VNET_DEFINE(int, useloopback) = 1; /* use loopback interface for
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* local traffic */
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static VNET_DEFINE(int, arp_proxyall) = 0;
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static VNET_DEFINE(int, arpt_down) = 20; /* keep incomplete entries for
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* 20 seconds */
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VNET_DEFINE(struct arpstat, arpstat); /* ARP statistics, see if_arp.h */
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static VNET_DEFINE(int, arp_maxhold) = 1;
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#define V_arpt_keep VNET(arpt_keep)
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#define V_arpt_down VNET(arpt_down)
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#define V_arp_maxtries VNET(arp_maxtries)
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#define V_arp_proxyall VNET(arp_proxyall)
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#define V_arpstat VNET(arpstat)
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#define V_arp_maxhold VNET(arp_maxhold)
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SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
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&VNET_NAME(arpt_keep), 0,
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"ARP entry lifetime in seconds");
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SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
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&VNET_NAME(arp_maxtries), 0,
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"ARP resolution attempts before returning error");
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SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
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&VNET_NAME(useloopback), 0,
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"Use the loopback interface for local traffic");
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SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
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&VNET_NAME(arp_proxyall), 0,
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"Enable proxy ARP for all suitable requests");
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SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, wait, CTLFLAG_RW,
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&VNET_NAME(arpt_down), 0,
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"Incomplete ARP entry lifetime in seconds");
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SYSCTL_VNET_STRUCT(_net_link_ether_arp, OID_AUTO, stats, CTLFLAG_RW,
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&VNET_NAME(arpstat), arpstat,
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"ARP statistics (struct arpstat, net/if_arp.h)");
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SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, maxhold, CTLFLAG_RW,
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&VNET_NAME(arp_maxhold), 0,
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"Number of packets to hold per ARP entry");
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static void arp_init(void);
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void arprequest(struct ifnet *,
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struct in_addr *, struct in_addr *, u_char *);
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static void arpintr(struct mbuf *);
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static void arptimer(void *);
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#ifdef INET
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static void in_arpinput(struct mbuf *);
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#endif
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static const struct netisr_handler arp_nh = {
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.nh_name = "arp",
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.nh_handler = arpintr,
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.nh_proto = NETISR_ARP,
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.nh_policy = NETISR_POLICY_SOURCE,
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};
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#ifdef AF_INET
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void arp_ifscrub(struct ifnet *ifp, uint32_t addr);
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/*
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* called by in_ifscrub to remove entry from the table when
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* the interface goes away
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*/
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void
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arp_ifscrub(struct ifnet *ifp, uint32_t addr)
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{
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struct sockaddr_in addr4;
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bzero((void *)&addr4, sizeof(addr4));
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addr4.sin_len = sizeof(addr4);
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addr4.sin_family = AF_INET;
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addr4.sin_addr.s_addr = addr;
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IF_AFDATA_LOCK(ifp);
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lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR),
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(struct sockaddr *)&addr4);
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IF_AFDATA_UNLOCK(ifp);
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}
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#endif
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/*
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* Timeout routine. Age arp_tab entries periodically.
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*/
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static void
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arptimer(void *arg)
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{
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struct ifnet *ifp;
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struct llentry *lle;
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int pkts_dropped;
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KASSERT(arg != NULL, ("%s: arg NULL", __func__));
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lle = (struct llentry *)arg;
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ifp = lle->lle_tbl->llt_ifp;
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CURVNET_SET(ifp->if_vnet);
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IF_AFDATA_LOCK(ifp);
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LLE_WLOCK(lle);
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if (lle->la_flags & LLE_STATIC)
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LLE_WUNLOCK(lle);
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else {
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if (!callout_pending(&lle->la_timer) &&
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callout_active(&lle->la_timer)) {
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callout_stop(&lle->la_timer);
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LLE_REMREF(lle);
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pkts_dropped = llentry_free(lle);
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ARPSTAT_ADD(dropped, pkts_dropped);
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ARPSTAT_INC(timeouts);
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} else {
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#ifdef DIAGNOSTIC
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struct sockaddr *l3addr = L3_ADDR(lle);
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log(LOG_INFO,
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"arptimer issue: %p, IPv4 address: \"%s\"\n", lle,
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inet_ntoa(
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((const struct sockaddr_in *)l3addr)->sin_addr));
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#endif
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LLE_WUNLOCK(lle);
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}
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}
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IF_AFDATA_UNLOCK(ifp);
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CURVNET_RESTORE();
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}
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/*
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* Broadcast an ARP request. Caller specifies:
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* - arp header source ip address
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* - arp header target ip address
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* - arp header source ethernet address
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*/
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void
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arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip,
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u_char *enaddr)
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{
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struct mbuf *m;
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struct arphdr *ah;
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struct sockaddr sa;
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if (sip == NULL) {
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/* XXX don't believe this can happen (or explain why) */
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/*
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* The caller did not supply a source address, try to find
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* a compatible one among those assigned to this interface.
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*/
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struct ifaddr *ifa;
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TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
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if (!ifa->ifa_addr ||
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ifa->ifa_addr->sa_family != AF_INET)
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continue;
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sip = &SIN(ifa->ifa_addr)->sin_addr;
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if (0 == ((sip->s_addr ^ tip->s_addr) &
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SIN(ifa->ifa_netmask)->sin_addr.s_addr) )
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break; /* found it. */
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}
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if (sip == NULL) {
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printf("%s: cannot find matching address\n", __func__);
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return;
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}
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}
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if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
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return;
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m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) +
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2*ifp->if_data.ifi_addrlen;
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m->m_pkthdr.len = m->m_len;
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MH_ALIGN(m, m->m_len);
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ah = mtod(m, struct arphdr *);
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bzero((caddr_t)ah, m->m_len);
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#ifdef MAC
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mac_netinet_arp_send(ifp, m);
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#endif
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ah->ar_pro = htons(ETHERTYPE_IP);
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ah->ar_hln = ifp->if_addrlen; /* hardware address length */
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ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
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ah->ar_op = htons(ARPOP_REQUEST);
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bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln);
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bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln);
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bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln);
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sa.sa_family = AF_ARP;
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sa.sa_len = 2;
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m->m_flags |= M_BCAST;
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(*ifp->if_output)(ifp, m, &sa, NULL);
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ARPSTAT_INC(txrequests);
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}
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/*
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* Resolve an IP address into an ethernet address.
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* On input:
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* ifp is the interface we use
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* rt0 is the route to the final destination (possibly useless)
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* m is the mbuf. May be NULL if we don't have a packet.
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* dst is the next hop,
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* desten is where we want the address.
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*
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* On success, desten is filled in and the function returns 0;
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* If the packet must be held pending resolution, we return EWOULDBLOCK
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* On other errors, we return the corresponding error code.
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* Note that m_freem() handles NULL.
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*/
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int
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arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
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struct sockaddr *dst, u_char *desten, struct llentry **lle)
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{
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struct llentry *la = 0;
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u_int flags = 0;
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struct mbuf *curr = NULL;
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struct mbuf *next = NULL;
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int error, renew;
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*lle = NULL;
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if (m != NULL) {
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if (m->m_flags & M_BCAST) {
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/* broadcast */
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(void)memcpy(desten,
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ifp->if_broadcastaddr, ifp->if_addrlen);
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return (0);
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}
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if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {
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/* multicast */
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ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
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return (0);
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}
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}
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retry:
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IF_AFDATA_RLOCK(ifp);
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la = lla_lookup(LLTABLE(ifp), flags, dst);
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IF_AFDATA_RUNLOCK(ifp);
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if ((la == NULL) && ((flags & LLE_EXCLUSIVE) == 0)
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&& ((ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0)) {
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flags |= (LLE_CREATE | LLE_EXCLUSIVE);
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IF_AFDATA_WLOCK(ifp);
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la = lla_lookup(LLTABLE(ifp), flags, dst);
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IF_AFDATA_WUNLOCK(ifp);
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}
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if (la == NULL) {
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if (flags & LLE_CREATE)
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log(LOG_DEBUG,
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"arpresolve: can't allocate llinfo for %s\n",
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inet_ntoa(SIN(dst)->sin_addr));
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m_freem(m);
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return (EINVAL);
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}
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if ((la->la_flags & LLE_VALID) &&
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((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) {
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bcopy(&la->ll_addr, desten, ifp->if_addrlen);
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/*
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* If entry has an expiry time and it is approaching,
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* see if we need to send an ARP request within this
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* arpt_down interval.
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*/
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if (!(la->la_flags & LLE_STATIC) &&
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time_uptime + la->la_preempt > la->la_expire) {
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arprequest(ifp, NULL,
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&SIN(dst)->sin_addr, IF_LLADDR(ifp));
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la->la_preempt--;
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}
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*lle = la;
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error = 0;
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goto done;
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}
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if (la->la_flags & LLE_STATIC) { /* should not happen! */
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log(LOG_DEBUG, "arpresolve: ouch, empty static llinfo for %s\n",
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inet_ntoa(SIN(dst)->sin_addr));
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m_freem(m);
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error = EINVAL;
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goto done;
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}
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renew = (la->la_asked == 0 || la->la_expire != time_uptime);
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if ((renew || m != NULL) && (flags & LLE_EXCLUSIVE) == 0) {
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flags |= LLE_EXCLUSIVE;
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LLE_RUNLOCK(la);
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goto retry;
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}
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/*
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* There is an arptab entry, but no ethernet address
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* response yet. Add the mbuf to the list, dropping
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* the oldest packet if we have exceeded the system
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* setting.
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*/
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if (m != NULL) {
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if (la->la_numheld >= V_arp_maxhold) {
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if (la->la_hold != NULL) {
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next = la->la_hold->m_nextpkt;
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m_freem(la->la_hold);
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la->la_hold = next;
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la->la_numheld--;
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ARPSTAT_INC(dropped);
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}
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}
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if (la->la_hold != NULL) {
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curr = la->la_hold;
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while (curr->m_nextpkt != NULL)
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curr = curr->m_nextpkt;
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curr->m_nextpkt = m;
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} else
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la->la_hold = m;
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la->la_numheld++;
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if (renew == 0 && (flags & LLE_EXCLUSIVE)) {
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flags &= ~LLE_EXCLUSIVE;
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LLE_DOWNGRADE(la);
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}
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}
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/*
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* Return EWOULDBLOCK if we have tried less than arp_maxtries. It
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* will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH
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* if we have already sent arp_maxtries ARP requests. Retransmit the
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* ARP request, but not faster than one request per second.
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*/
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if (la->la_asked < V_arp_maxtries)
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error = EWOULDBLOCK; /* First request. */
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else
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error = rt0 != NULL && (rt0->rt_flags & RTF_GATEWAY) ?
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EHOSTUNREACH : EHOSTDOWN;
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if (renew) {
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int canceled;
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LLE_ADDREF(la);
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la->la_expire = time_uptime;
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canceled = callout_reset(&la->la_timer, hz * V_arpt_down,
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arptimer, la);
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if (canceled)
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LLE_REMREF(la);
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la->la_asked++;
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LLE_WUNLOCK(la);
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arprequest(ifp, NULL, &SIN(dst)->sin_addr,
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IF_LLADDR(ifp));
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return (error);
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}
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done:
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if (flags & LLE_EXCLUSIVE)
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LLE_WUNLOCK(la);
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else
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LLE_RUNLOCK(la);
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return (error);
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}
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/*
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* Common length and type checks are done here,
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* then the protocol-specific routine is called.
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*/
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static void
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arpintr(struct mbuf *m)
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{
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struct arphdr *ar;
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if (m->m_len < sizeof(struct arphdr) &&
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((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
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log(LOG_ERR, "arp: runt packet -- m_pullup failed\n");
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return;
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}
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ar = mtod(m, struct arphdr *);
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if (ntohs(ar->ar_hrd) != ARPHRD_ETHER &&
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ntohs(ar->ar_hrd) != ARPHRD_IEEE802 &&
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ntohs(ar->ar_hrd) != ARPHRD_ARCNET &&
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ntohs(ar->ar_hrd) != ARPHRD_IEEE1394) {
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log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n",
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(unsigned char *)&ar->ar_hrd, "");
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m_freem(m);
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return;
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}
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if (m->m_len < arphdr_len(ar)) {
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if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
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log(LOG_ERR, "arp: runt packet\n");
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m_freem(m);
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return;
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}
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ar = mtod(m, struct arphdr *);
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}
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ARPSTAT_INC(received);
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switch (ntohs(ar->ar_pro)) {
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#ifdef INET
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case ETHERTYPE_IP:
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in_arpinput(m);
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return;
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#endif
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}
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m_freem(m);
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}
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#ifdef INET
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/*
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* ARP for Internet protocols on 10 Mb/s Ethernet.
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* Algorithm is that given in RFC 826.
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* In addition, a sanity check is performed on the sender
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* protocol address, to catch impersonators.
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* We no longer handle negotiations for use of trailer protocol:
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* Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
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* along with IP replies if we wanted trailers sent to us,
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* and also sent them in response to IP replies.
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* This allowed either end to announce the desire to receive
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* trailer packets.
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* We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
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* but formerly didn't normally send requests.
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*/
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static int log_arp_wrong_iface = 1;
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static int log_arp_movements = 1;
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static int log_arp_permanent_modify = 1;
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SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
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&log_arp_wrong_iface, 0,
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"log arp packets arriving on the wrong interface");
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SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
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&log_arp_movements, 0,
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"log arp replies from MACs different than the one in the cache");
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SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
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&log_arp_permanent_modify, 0,
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"log arp replies from MACs different than the one in the permanent arp entry");
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static void
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in_arpinput(struct mbuf *m)
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{
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struct arphdr *ah;
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struct ifnet *ifp = m->m_pkthdr.rcvif;
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struct llentry *la = NULL;
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struct rtentry *rt;
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struct ifaddr *ifa;
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struct in_ifaddr *ia;
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struct sockaddr sa;
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struct in_addr isaddr, itaddr, myaddr;
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u_int8_t *enaddr = NULL;
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int op, flags;
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int req_len;
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int bridged = 0, is_bridge = 0;
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int carp_match = 0;
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struct sockaddr_in sin;
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sin.sin_len = sizeof(struct sockaddr_in);
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sin.sin_family = AF_INET;
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sin.sin_addr.s_addr = 0;
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if (ifp->if_bridge)
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bridged = 1;
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if (ifp->if_type == IFT_BRIDGE)
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is_bridge = 1;
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req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
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if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
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log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n");
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return;
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}
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ah = mtod(m, struct arphdr *);
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/*
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* ARP is only for IPv4 so we can reject packets with
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* a protocol length not equal to an IPv4 address.
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*/
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if (ah->ar_pln != sizeof(struct in_addr)) {
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log(LOG_ERR, "in_arp: requested protocol length != %zu\n",
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sizeof(struct in_addr));
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return;
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}
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if (ETHER_IS_MULTICAST(ar_sha(ah))) {
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log(LOG_ERR, "in_arp: source hardware address is multicast.");
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return;
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}
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op = ntohs(ah->ar_op);
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(void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
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(void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
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if (op == ARPOP_REPLY)
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ARPSTAT_INC(rxreplies);
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/*
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* For a bridge, we want to check the address irrespective
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* of the receive interface. (This will change slightly
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* when we have clusters of interfaces).
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* If the interface does not match, but the recieving interface
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* is part of carp, we call carp_iamatch to see if this is a
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* request for the virtual host ip.
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* XXX: This is really ugly!
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*/
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IN_IFADDR_RLOCK();
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LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
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if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
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ia->ia_ifp == ifp) &&
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itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
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ifa_ref(&ia->ia_ifa);
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IN_IFADDR_RUNLOCK();
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goto match;
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}
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if (ifp->if_carp != NULL &&
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(*carp_iamatch_p)(ifp, ia, &isaddr, &enaddr) &&
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itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
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carp_match = 1;
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ifa_ref(&ia->ia_ifa);
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IN_IFADDR_RUNLOCK();
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goto match;
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}
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}
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LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
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if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
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ia->ia_ifp == ifp) &&
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isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
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ifa_ref(&ia->ia_ifa);
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IN_IFADDR_RUNLOCK();
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goto match;
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}
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#define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \
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(ia->ia_ifp->if_bridge == ifp->if_softc && \
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!bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \
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addr == ia->ia_addr.sin_addr.s_addr)
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/*
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* Check the case when bridge shares its MAC address with
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* some of its children, so packets are claimed by bridge
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* itself (bridge_input() does it first), but they are really
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* meant to be destined to the bridge member.
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*/
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if (is_bridge) {
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LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
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if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) {
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ifa_ref(&ia->ia_ifa);
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ifp = ia->ia_ifp;
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IN_IFADDR_RUNLOCK();
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goto match;
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}
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}
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}
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#undef BDG_MEMBER_MATCHES_ARP
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IN_IFADDR_RUNLOCK();
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/*
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* No match, use the first inet address on the receive interface
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* as a dummy address for the rest of the function.
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*/
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IF_ADDR_LOCK(ifp);
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TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
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if (ifa->ifa_addr->sa_family == AF_INET) {
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ia = ifatoia(ifa);
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ifa_ref(ifa);
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IF_ADDR_UNLOCK(ifp);
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goto match;
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}
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IF_ADDR_UNLOCK(ifp);
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/*
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* If bridging, fall back to using any inet address.
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*/
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IN_IFADDR_RLOCK();
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if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) {
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IN_IFADDR_RUNLOCK();
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goto drop;
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}
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ifa_ref(&ia->ia_ifa);
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IN_IFADDR_RUNLOCK();
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match:
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if (!enaddr)
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enaddr = (u_int8_t *)IF_LLADDR(ifp);
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myaddr = ia->ia_addr.sin_addr;
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ifa_free(&ia->ia_ifa);
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if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen))
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goto drop; /* it's from me, ignore it. */
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if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
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log(LOG_ERR,
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"arp: link address is broadcast for IP address %s!\n",
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inet_ntoa(isaddr));
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goto drop;
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}
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/*
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* Warn if another host is using the same IP address, but only if the
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* IP address isn't 0.0.0.0, which is used for DHCP only, in which
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* case we suppress the warning to avoid false positive complaints of
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* potential misconfiguration.
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*/
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if (!bridged && isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) {
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log(LOG_ERR,
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"arp: %*D is using my IP address %s on %s!\n",
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ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
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inet_ntoa(isaddr), ifp->if_xname);
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itaddr = myaddr;
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ARPSTAT_INC(dupips);
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goto reply;
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}
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if (ifp->if_flags & IFF_STATICARP)
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goto reply;
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bzero(&sin, sizeof(sin));
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sin.sin_len = sizeof(struct sockaddr_in);
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sin.sin_family = AF_INET;
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sin.sin_addr = isaddr;
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flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0;
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flags |= LLE_EXCLUSIVE;
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IF_AFDATA_LOCK(ifp);
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la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin);
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IF_AFDATA_UNLOCK(ifp);
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if (la != NULL) {
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/* the following is not an error when doing bridging */
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if (!bridged && la->lle_tbl->llt_ifp != ifp && !carp_match) {
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if (log_arp_wrong_iface)
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log(LOG_ERR, "arp: %s is on %s "
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"but got reply from %*D on %s\n",
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inet_ntoa(isaddr),
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la->lle_tbl->llt_ifp->if_xname,
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ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
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ifp->if_xname);
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LLE_WUNLOCK(la);
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goto reply;
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}
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if ((la->la_flags & LLE_VALID) &&
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bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
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if (la->la_flags & LLE_STATIC) {
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LLE_WUNLOCK(la);
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log(LOG_ERR,
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"arp: %*D attempts to modify permanent "
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"entry for %s on %s\n",
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ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
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inet_ntoa(isaddr), ifp->if_xname);
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goto reply;
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}
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if (log_arp_movements) {
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log(LOG_INFO, "arp: %s moved from %*D "
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"to %*D on %s\n",
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inet_ntoa(isaddr),
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ifp->if_addrlen,
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(u_char *)&la->ll_addr, ":",
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ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
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ifp->if_xname);
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}
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}
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if (ifp->if_addrlen != ah->ar_hln) {
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LLE_WUNLOCK(la);
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log(LOG_WARNING,
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"arp from %*D: addr len: new %d, i/f %d (ignored)",
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ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
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ah->ar_hln, ifp->if_addrlen);
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goto drop;
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}
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(void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
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la->la_flags |= LLE_VALID;
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EVENTHANDLER_INVOKE(arp_update_event, la);
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if (!(la->la_flags & LLE_STATIC)) {
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int canceled;
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LLE_ADDREF(la);
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la->la_expire = time_uptime + V_arpt_keep;
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canceled = callout_reset(&la->la_timer,
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hz * V_arpt_keep, arptimer, la);
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if (canceled)
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LLE_REMREF(la);
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}
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la->la_asked = 0;
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la->la_preempt = V_arp_maxtries;
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/*
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* The packets are all freed within the call to the output
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* routine.
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*
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* NB: The lock MUST be released before the call to the
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* output routine.
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*/
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if (la->la_hold != NULL) {
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struct mbuf *m_hold, *m_hold_next;
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m_hold = la->la_hold;
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la->la_hold = NULL;
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la->la_numheld = 0;
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memcpy(&sa, L3_ADDR(la), sizeof(sa));
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LLE_WUNLOCK(la);
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for (; m_hold != NULL; m_hold = m_hold_next) {
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m_hold_next = m_hold->m_nextpkt;
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m_hold->m_nextpkt = NULL;
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(*ifp->if_output)(ifp, m_hold, &sa, NULL);
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}
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} else
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LLE_WUNLOCK(la);
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} /* end of FIB loop */
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reply:
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if (op != ARPOP_REQUEST)
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goto drop;
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ARPSTAT_INC(rxrequests);
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if (itaddr.s_addr == myaddr.s_addr) {
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/* Shortcut.. the receiving interface is the target. */
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(void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
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(void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
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} else {
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struct llentry *lle = NULL;
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sin.sin_addr = itaddr;
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IF_AFDATA_LOCK(ifp);
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lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
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IF_AFDATA_UNLOCK(ifp);
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if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
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(void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
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(void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
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LLE_RUNLOCK(lle);
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} else {
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if (lle != NULL)
|
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LLE_RUNLOCK(lle);
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if (!V_arp_proxyall)
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goto drop;
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sin.sin_addr = itaddr;
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/* XXX MRT use table 0 for arp reply */
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rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
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if (!rt)
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goto drop;
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/*
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* Don't send proxies for nodes on the same interface
|
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* as this one came out of, or we'll get into a fight
|
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* over who claims what Ether address.
|
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*/
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if (!rt->rt_ifp || rt->rt_ifp == ifp) {
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RTFREE_LOCKED(rt);
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goto drop;
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}
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RTFREE_LOCKED(rt);
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|
|
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(void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
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(void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
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|
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/*
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* Also check that the node which sent the ARP packet
|
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* is on the interface we expect it to be on. This
|
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* avoids ARP chaos if an interface is connected to the
|
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* wrong network.
|
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*/
|
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sin.sin_addr = isaddr;
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|
|
|
/* XXX MRT use table 0 for arp checks */
|
|
rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
|
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if (!rt)
|
|
goto drop;
|
|
if (rt->rt_ifp != ifp) {
|
|
log(LOG_INFO, "arp_proxy: ignoring request"
|
|
" from %s via %s, expecting %s\n",
|
|
inet_ntoa(isaddr), ifp->if_xname,
|
|
rt->rt_ifp->if_xname);
|
|
RTFREE_LOCKED(rt);
|
|
goto drop;
|
|
}
|
|
RTFREE_LOCKED(rt);
|
|
|
|
#ifdef DEBUG_PROXY
|
|
printf("arp: proxying for %s\n",
|
|
inet_ntoa(itaddr));
|
|
#endif
|
|
}
|
|
}
|
|
|
|
if (itaddr.s_addr == myaddr.s_addr &&
|
|
IN_LINKLOCAL(ntohl(itaddr.s_addr))) {
|
|
/* RFC 3927 link-local IPv4; always reply by broadcast. */
|
|
#ifdef DEBUG_LINKLOCAL
|
|
printf("arp: sending reply for link-local addr %s\n",
|
|
inet_ntoa(itaddr));
|
|
#endif
|
|
m->m_flags |= M_BCAST;
|
|
m->m_flags &= ~M_MCAST;
|
|
} else {
|
|
/* default behaviour; never reply by broadcast. */
|
|
m->m_flags &= ~(M_BCAST|M_MCAST);
|
|
}
|
|
(void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
|
|
(void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
|
|
ah->ar_op = htons(ARPOP_REPLY);
|
|
ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
|
|
m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
|
|
m->m_pkthdr.len = m->m_len;
|
|
sa.sa_family = AF_ARP;
|
|
sa.sa_len = 2;
|
|
(*ifp->if_output)(ifp, m, &sa, NULL);
|
|
ARPSTAT_INC(txreplies);
|
|
return;
|
|
|
|
drop:
|
|
m_freem(m);
|
|
}
|
|
#endif
|
|
|
|
void
|
|
arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
|
|
{
|
|
struct llentry *lle;
|
|
|
|
if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) {
|
|
arprequest(ifp, &IA_SIN(ifa)->sin_addr,
|
|
&IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
|
|
/*
|
|
* interface address is considered static entry
|
|
* because the output of the arp utility shows
|
|
* that L2 entry as permanent
|
|
*/
|
|
IF_AFDATA_LOCK(ifp);
|
|
lle = lla_lookup(LLTABLE(ifp), (LLE_CREATE | LLE_IFADDR | LLE_STATIC),
|
|
(struct sockaddr *)IA_SIN(ifa));
|
|
IF_AFDATA_UNLOCK(ifp);
|
|
if (lle == NULL)
|
|
log(LOG_INFO, "arp_ifinit: cannot create arp "
|
|
"entry for interface address\n");
|
|
else
|
|
LLE_RUNLOCK(lle);
|
|
}
|
|
ifa->ifa_rtrequest = NULL;
|
|
}
|
|
|
|
void
|
|
arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr)
|
|
{
|
|
if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
|
|
arprequest(ifp, &IA_SIN(ifa)->sin_addr,
|
|
&IA_SIN(ifa)->sin_addr, enaddr);
|
|
ifa->ifa_rtrequest = NULL;
|
|
}
|
|
|
|
static void
|
|
arp_init(void)
|
|
{
|
|
|
|
netisr_register(&arp_nh);
|
|
}
|
|
SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);
|