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28e1f17c81
freebsd-nq/sys/netinet/if_ether.c
Gleb Smirnoff 28e1f17c81 Revert a small part of the r198301, that is entirely unrelated to the 
r198301 itself. It also broke the logic of not sending more than one
ARP request per second, that consequently lead to a potential problem
of flooding network with broadcast packets.

MFC after:	1 week
2010-10-29 10:57:18 +00:00

862 lines
24 KiB
C
Raw Blame History

/*-
* Copyright (c) 1982, 1986, 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)if_ether.c 8.1 (Berkeley) 6/10/93
*/
/*
* Ethernet address resolution protocol.
* TODO:
* add "inuse/lock" bit (or ref. count) along with valid bit
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/queue.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/netisr.h>
#include <net/if_llc.h>
#include <net/ethernet.h>
#include <net/route.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <net/if_llatbl.h>
#include <netinet/if_ether.h>
#if defined(INET) || defined(INET6)
#include <netinet/ip_carp.h>
#endif
#include <net/if_arc.h>
#include <net/iso88025.h>
#include <security/mac/mac_framework.h>
#define SIN(s) ((struct sockaddr_in *)s)
#define SDL(s) ((struct sockaddr_dl *)s)
SYSCTL_DECL(_net_link_ether);
SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
SYSCTL_NODE(_net_link_ether, PF_ARP, arp, CTLFLAG_RW, 0, "");
/* timer values */
static VNET_DEFINE(int, arpt_keep) = (20*60); /* once resolved, good for 20
* minutes */
static VNET_DEFINE(int, arp_maxtries) = 5;
VNET_DEFINE(int, useloopback) = 1; /* use loopback interface for
* local traffic */
static VNET_DEFINE(int, arp_proxyall) = 0;
static VNET_DEFINE(int, arpt_down) = 20; /* keep incomplete entries for
* 20 seconds */
static VNET_DEFINE(struct arpstat, arpstat); /* ARP statistics, see if_arp.h */
#define V_arpt_keep VNET(arpt_keep)
#define V_arpt_down VNET(arpt_down)
#define V_arp_maxtries VNET(arp_maxtries)
#define V_arp_proxyall VNET(arp_proxyall)
#define V_arpstat VNET(arpstat)
SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
&VNET_NAME(arpt_keep), 0,
"ARP entry lifetime in seconds");
SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
&VNET_NAME(arp_maxtries), 0,
"ARP resolution attempts before returning error");
SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
&VNET_NAME(useloopback), 0,
"Use the loopback interface for local traffic");
SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
&VNET_NAME(arp_proxyall), 0,
"Enable proxy ARP for all suitable requests");
SYSCTL_VNET_STRUCT(_net_link_ether_arp, OID_AUTO, stats, CTLFLAG_RW,
&VNET_NAME(arpstat), arpstat,
"ARP statistics (struct arpstat, net/if_arp.h)");
static void arp_init(void);
void arprequest(struct ifnet *,
struct in_addr *, struct in_addr *, u_char *);
static void arpintr(struct mbuf *);
static void arptimer(void *);
#ifdef INET
static void in_arpinput(struct mbuf *);
#endif
static const struct netisr_handler arp_nh = {
.nh_name = "arp",
.nh_handler = arpintr,
.nh_proto = NETISR_ARP,
.nh_policy = NETISR_POLICY_SOURCE,
};
#ifdef AF_INET
void arp_ifscrub(struct ifnet *ifp, uint32_t addr);
/*
* called by in_ifscrub to remove entry from the table when
* the interface goes away
*/
void
arp_ifscrub(struct ifnet *ifp, uint32_t addr)
{
struct sockaddr_in addr4;
bzero((void *)&addr4, sizeof(addr4));
addr4.sin_len = sizeof(addr4);
addr4.sin_family = AF_INET;
addr4.sin_addr.s_addr = addr;
CURVNET_SET(ifp->if_vnet);
IF_AFDATA_LOCK(ifp);
lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR),
(struct sockaddr *)&addr4);
IF_AFDATA_UNLOCK(ifp);
CURVNET_RESTORE();
}
#endif
/*
* Timeout routine. Age arp_tab entries periodically.
*/
static void
arptimer(void *arg)
{
struct ifnet *ifp;
struct llentry *lle;
KASSERT(arg != NULL, ("%s: arg NULL", __func__));
lle = (struct llentry *)arg;
ifp = lle->lle_tbl->llt_ifp;
CURVNET_SET(ifp->if_vnet);
IF_AFDATA_LOCK(ifp);
LLE_WLOCK(lle);
if (lle->la_flags & LLE_STATIC)
LLE_WUNLOCK(lle);
else {
if (!callout_pending(&lle->la_timer) &&
callout_active(&lle->la_timer)) {
callout_stop(&lle->la_timer);
LLE_REMREF(lle);
(void) llentry_free(lle);
ARPSTAT_INC(timeouts);
}
#ifdef DIAGNOSTIC
else {
struct sockaddr *l3addr = L3_ADDR(lle);
log(LOG_INFO,
"arptimer issue: %p, IPv4 address: \"%s\"\n", lle,
inet_ntoa(
((const struct sockaddr_in *)l3addr)->sin_addr));
}
#endif
}
IF_AFDATA_UNLOCK(ifp);
CURVNET_RESTORE();
}
/*
* Broadcast an ARP request. Caller specifies:
* - arp header source ip address
* - arp header target ip address
* - arp header source ethernet address
*/
void
arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip,
u_char *enaddr)
{
struct mbuf *m;
struct arphdr *ah;
struct sockaddr sa;
if (sip == NULL) {
/* XXX don't believe this can happen (or explain why) */
/*
* The caller did not supply a source address, try to find
* a compatible one among those assigned to this interface.
*/
struct ifaddr *ifa;
TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
if (!ifa->ifa_addr ||
ifa->ifa_addr->sa_family != AF_INET)
continue;
sip = &SIN(ifa->ifa_addr)->sin_addr;
if (0 == ((sip->s_addr ^ tip->s_addr) &
SIN(ifa->ifa_netmask)->sin_addr.s_addr) )
break; /* found it. */
}
if (sip == NULL) {
printf("%s: cannot find matching address\n", __func__);
return;
}
}
if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
return;
m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) +
2*ifp->if_data.ifi_addrlen;
m->m_pkthdr.len = m->m_len;
MH_ALIGN(m, m->m_len);
ah = mtod(m, struct arphdr *);
bzero((caddr_t)ah, m->m_len);
#ifdef MAC
mac_netinet_arp_send(ifp, m);
#endif
ah->ar_pro = htons(ETHERTYPE_IP);
ah->ar_hln = ifp->if_addrlen; /* hardware address length */
ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
ah->ar_op = htons(ARPOP_REQUEST);
bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln);
bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln);
bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln);
sa.sa_family = AF_ARP;
sa.sa_len = 2;
m->m_flags |= M_BCAST;
(*ifp->if_output)(ifp, m, &sa, NULL);
ARPSTAT_INC(txrequests);
}
/*
* Resolve an IP address into an ethernet address.
* On input:
* ifp is the interface we use
* rt0 is the route to the final destination (possibly useless)
* m is the mbuf. May be NULL if we don't have a packet.
* dst is the next hop,
* desten is where we want the address.
*
* On success, desten is filled in and the function returns 0;
* If the packet must be held pending resolution, we return EWOULDBLOCK
* On other errors, we return the corresponding error code.
* Note that m_freem() handles NULL.
*/
int
arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
struct sockaddr *dst, u_char *desten, struct llentry **lle)
{
struct llentry *la = 0;
u_int flags = 0;
int error, renew;
*lle = NULL;
if (m != NULL) {
if (m->m_flags & M_BCAST) {
/* broadcast */
(void)memcpy(desten,
ifp->if_broadcastaddr, ifp->if_addrlen);
return (0);
}
if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {
/* multicast */
ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
return (0);
}
}
/* XXXXX
*/
retry:
IF_AFDATA_RLOCK(ifp);
la = lla_lookup(LLTABLE(ifp), flags, dst);
IF_AFDATA_RUNLOCK(ifp);
if ((la == NULL) && ((flags & LLE_EXCLUSIVE) == 0)
&& ((ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0)) {
flags |= (LLE_CREATE | LLE_EXCLUSIVE);
IF_AFDATA_WLOCK(ifp);
la = lla_lookup(LLTABLE(ifp), flags, dst);
IF_AFDATA_WUNLOCK(ifp);
}
if (la == NULL) {
if (flags & LLE_CREATE)
log(LOG_DEBUG,
"arpresolve: can't allocate llinfo for %s\n",
inet_ntoa(SIN(dst)->sin_addr));
m_freem(m);
return (EINVAL);
}
if ((la->la_flags & LLE_VALID) &&
((la->la_flags & LLE_STATIC) || la->la_expire > time_second)) {
bcopy(&la->ll_addr, desten, ifp->if_addrlen);
/*
* If entry has an expiry time and it is approaching,
* see if we need to send an ARP request within this
* arpt_down interval.
*/
if (!(la->la_flags & LLE_STATIC) &&
time_second + la->la_preempt > la->la_expire) {
arprequest(ifp, NULL,
&SIN(dst)->sin_addr, IF_LLADDR(ifp));
la->la_preempt--;
}
*lle = la;
error = 0;
goto done;
}
if (la->la_flags & LLE_STATIC) { /* should not happen! */
log(LOG_DEBUG, "arpresolve: ouch, empty static llinfo for %s\n",
inet_ntoa(SIN(dst)->sin_addr));
m_freem(m);
error = EINVAL;
goto done;
}
renew = (la->la_asked == 0 || la->la_expire != time_second);
if ((renew || m != NULL) && (flags & LLE_EXCLUSIVE) == 0) {
flags |= LLE_EXCLUSIVE;
LLE_RUNLOCK(la);
goto retry;
}
/*
* There is an arptab entry, but no ethernet address
* response yet. Replace the held mbuf with this
* latest one.
*/
if (m != NULL) {
if (la->la_hold != NULL) {
m_freem(la->la_hold);
ARPSTAT_INC(dropped);
}
la->la_hold = m;
if (renew == 0 && (flags & LLE_EXCLUSIVE)) {
flags &= ~LLE_EXCLUSIVE;
LLE_DOWNGRADE(la);
}
}
/*
* Return EWOULDBLOCK if we have tried less than arp_maxtries. It
* will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH
* if we have already sent arp_maxtries ARP requests. Retransmit the
* ARP request, but not faster than one request per second.
*/
if (la->la_asked < V_arp_maxtries)
error = EWOULDBLOCK; /* First request. */
else
error = rt0 != NULL && (rt0->rt_flags & RTF_GATEWAY) ?
EHOSTUNREACH : EHOSTDOWN;
if (renew) {
int canceled;
LLE_ADDREF(la);
la->la_expire = time_second;
canceled = callout_reset(&la->la_timer, hz * V_arpt_down,
arptimer, la);
if (canceled)
LLE_REMREF(la);
la->la_asked++;
LLE_WUNLOCK(la);
arprequest(ifp, NULL, &SIN(dst)->sin_addr,
IF_LLADDR(ifp));
return (error);
}
done:
if (flags & LLE_EXCLUSIVE)
LLE_WUNLOCK(la);
else
LLE_RUNLOCK(la);
return (error);
}
/*
* Common length and type checks are done here,
* then the protocol-specific routine is called.
*/
static void
arpintr(struct mbuf *m)
{
struct arphdr *ar;
if (m->m_len < sizeof(struct arphdr) &&
((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
log(LOG_ERR, "arp: runt packet -- m_pullup failed\n");
return;
}
ar = mtod(m, struct arphdr *);
if (ntohs(ar->ar_hrd) != ARPHRD_ETHER &&
ntohs(ar->ar_hrd) != ARPHRD_IEEE802 &&
ntohs(ar->ar_hrd) != ARPHRD_ARCNET &&
ntohs(ar->ar_hrd) != ARPHRD_IEEE1394) {
log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n",
(unsigned char *)&ar->ar_hrd, "");
m_freem(m);
return;
}
if (m->m_len < arphdr_len(ar)) {
if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
log(LOG_ERR, "arp: runt packet\n");
m_freem(m);
return;
}
ar = mtod(m, struct arphdr *);
}
ARPSTAT_INC(received);
switch (ntohs(ar->ar_pro)) {
#ifdef INET
case ETHERTYPE_IP:
in_arpinput(m);
return;
#endif
}
m_freem(m);
}
#ifdef INET
/*
* ARP for Internet protocols on 10 Mb/s Ethernet.
* Algorithm is that given in RFC 826.
* In addition, a sanity check is performed on the sender
* protocol address, to catch impersonators.
* We no longer handle negotiations for use of trailer protocol:
* Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
* along with IP replies if we wanted trailers sent to us,
* and also sent them in response to IP replies.
* This allowed either end to announce the desire to receive
* trailer packets.
* We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
* but formerly didn't normally send requests.
*/
static int log_arp_wrong_iface = 1;
static int log_arp_movements = 1;
static int log_arp_permanent_modify = 1;
SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
&log_arp_wrong_iface, 0,
"log arp packets arriving on the wrong interface");
SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
&log_arp_movements, 0,
"log arp replies from MACs different than the one in the cache");
SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
&log_arp_permanent_modify, 0,
"log arp replies from MACs different than the one in the permanent arp entry");
static void
in_arpinput(struct mbuf *m)
{
struct arphdr *ah;
struct ifnet *ifp = m->m_pkthdr.rcvif;
struct llentry *la = NULL;
struct rtentry *rt;
struct ifaddr *ifa;
struct in_ifaddr *ia;
struct mbuf *hold;
struct sockaddr sa;
struct in_addr isaddr, itaddr, myaddr;
u_int8_t *enaddr = NULL;
int op, flags;
int req_len;
int bridged = 0, is_bridge = 0;
int carp_match = 0;
struct sockaddr_in sin;
sin.sin_len = sizeof(struct sockaddr_in);
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = 0;
if (ifp->if_bridge)
bridged = 1;
if (ifp->if_type == IFT_BRIDGE)
is_bridge = 1;
req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n");
return;
}
ah = mtod(m, struct arphdr *);
op = ntohs(ah->ar_op);
(void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
(void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
if (op == ARPOP_REPLY)
ARPSTAT_INC(rxreplies);
/*
* For a bridge, we want to check the address irrespective
* of the receive interface. (This will change slightly
* when we have clusters of interfaces).
* If the interface does not match, but the recieving interface
* is part of carp, we call carp_iamatch to see if this is a
* request for the virtual host ip.
* XXX: This is really ugly!
*/
IN_IFADDR_RLOCK();
LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
if (((bridged && ia->ia_ifp->if_bridge != NULL) ||
ia->ia_ifp == ifp) &&
itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
ifa_ref(&ia->ia_ifa);
IN_IFADDR_RUNLOCK();
goto match;
}
if (ifp->if_carp != NULL &&
(*carp_iamatch_p)(ifp, ia, &isaddr, &enaddr) &&
itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
carp_match = 1;
ifa_ref(&ia->ia_ifa);
IN_IFADDR_RUNLOCK();
goto match;
}
}
LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
if (((bridged && ia->ia_ifp->if_bridge != NULL) ||
ia->ia_ifp == ifp) &&
isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
ifa_ref(&ia->ia_ifa);
IN_IFADDR_RUNLOCK();
goto match;
}
#define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \
(ia->ia_ifp->if_bridge == ifp->if_softc && \
!bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \
addr == ia->ia_addr.sin_addr.s_addr)
/*
* Check the case when bridge shares its MAC address with
* some of its children, so packets are claimed by bridge
* itself (bridge_input() does it first), but they are really
* meant to be destined to the bridge member.
*/
if (is_bridge) {
LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) {
ifa_ref(&ia->ia_ifa);
ifp = ia->ia_ifp;
IN_IFADDR_RUNLOCK();
goto match;
}
}
}
#undef BDG_MEMBER_MATCHES_ARP
IN_IFADDR_RUNLOCK();
/*
* No match, use the first inet address on the receive interface
* as a dummy address for the rest of the function.
*/
IF_ADDR_LOCK(ifp);
TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
if (ifa->ifa_addr->sa_family == AF_INET) {
ia = ifatoia(ifa);
ifa_ref(ifa);
IF_ADDR_UNLOCK(ifp);
goto match;
}
IF_ADDR_UNLOCK(ifp);
/*
* If bridging, fall back to using any inet address.
*/
IN_IFADDR_RLOCK();
if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) {
IN_IFADDR_RUNLOCK();
goto drop;
}
ifa_ref(&ia->ia_ifa);
IN_IFADDR_RUNLOCK();
match:
if (!enaddr)
enaddr = (u_int8_t *)IF_LLADDR(ifp);
myaddr = ia->ia_addr.sin_addr;
ifa_free(&ia->ia_ifa);
if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen))
goto drop; /* it's from me, ignore it. */
if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
log(LOG_ERR,
"arp: link address is broadcast for IP address %s!\n",
inet_ntoa(isaddr));
goto drop;
}
/*
* Warn if another host is using the same IP address, but only if the
* IP address isn't 0.0.0.0, which is used for DHCP only, in which
* case we suppress the warning to avoid false positive complaints of
* potential misconfiguration.
*/
if (!bridged && isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) {
log(LOG_ERR,
"arp: %*D is using my IP address %s on %s!\n",
ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
inet_ntoa(isaddr), ifp->if_xname);
itaddr = myaddr;
ARPSTAT_INC(dupips);
goto reply;
}
if (ifp->if_flags & IFF_STATICARP)
goto reply;
bzero(&sin, sizeof(sin));
sin.sin_len = sizeof(struct sockaddr_in);
sin.sin_family = AF_INET;
sin.sin_addr = isaddr;
flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0;
flags |= LLE_EXCLUSIVE;
IF_AFDATA_LOCK(ifp);
la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin);
IF_AFDATA_UNLOCK(ifp);
if (la != NULL) {
/* the following is not an error when doing bridging */
if (!bridged && la->lle_tbl->llt_ifp != ifp && !carp_match) {
if (log_arp_wrong_iface)
log(LOG_ERR, "arp: %s is on %s "
"but got reply from %*D on %s\n",
inet_ntoa(isaddr),
la->lle_tbl->llt_ifp->if_xname,
ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
ifp->if_xname);
LLE_WUNLOCK(la);
goto reply;
}
if ((la->la_flags & LLE_VALID) &&
bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
if (la->la_flags & LLE_STATIC) {
LLE_WUNLOCK(la);
log(LOG_ERR,
"arp: %*D attempts to modify permanent "
"entry for %s on %s\n",
ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
inet_ntoa(isaddr), ifp->if_xname);
goto reply;
}
if (log_arp_movements) {
log(LOG_INFO, "arp: %s moved from %*D "
"to %*D on %s\n",
inet_ntoa(isaddr),
ifp->if_addrlen,
(u_char *)&la->ll_addr, ":",
ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
ifp->if_xname);
}
}
if (ifp->if_addrlen != ah->ar_hln) {
LLE_WUNLOCK(la);
log(LOG_WARNING,
"arp from %*D: addr len: new %d, i/f %d (ignored)",
ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
ah->ar_hln, ifp->if_addrlen);
goto reply;
}
(void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
la->la_flags |= LLE_VALID;
EVENTHANDLER_INVOKE(arp_update_event, la);
if (!(la->la_flags & LLE_STATIC)) {
int canceled;
LLE_ADDREF(la);
la->la_expire = time_second + V_arpt_keep;
canceled = callout_reset(&la->la_timer,
hz * V_arpt_keep, arptimer, la);
if (canceled)
LLE_REMREF(la);
}
la->la_asked = 0;
la->la_preempt = V_arp_maxtries;
hold = la->la_hold;
if (hold != NULL) {
la->la_hold = NULL;
memcpy(&sa, L3_ADDR(la), sizeof(sa));
}
LLE_WUNLOCK(la);
if (hold != NULL)
(*ifp->if_output)(ifp, hold, &sa, NULL);
}
reply:
if (op != ARPOP_REQUEST)
goto drop;
ARPSTAT_INC(rxrequests);
if (itaddr.s_addr == myaddr.s_addr) {
/* Shortcut.. the receiving interface is the target. */
(void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
(void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
} else {
struct llentry *lle = NULL;
sin.sin_addr = itaddr;
IF_AFDATA_LOCK(ifp);
lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
IF_AFDATA_UNLOCK(ifp);
if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
(void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
(void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
LLE_RUNLOCK(lle);
} else {
if (lle != NULL)
LLE_RUNLOCK(lle);
if (!V_arp_proxyall)
goto drop;
sin.sin_addr = itaddr;
/* XXX MRT use table 0 for arp reply */
rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
if (!rt)
goto drop;
/*
* Don't send proxies for nodes on the same interface
* as this one came out of, or we'll get into a fight
* over who claims what Ether address.
*/
if (!rt->rt_ifp || rt->rt_ifp == ifp) {
RTFREE_LOCKED(rt);
goto drop;
}
RTFREE_LOCKED(rt);
(void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
(void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
/*
* Also check that the node which sent the ARP packet
* is on the the interface we expect it to be on. This
* avoids ARP chaos if an interface is connected to the
* wrong network.
*/
sin.sin_addr = isaddr;
/* XXX MRT use table 0 for arp checks */
rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
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);
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