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freebsd-skq/sys/netinet/if_ether.c
Kip Macy 5e96c0a13e Fix missed unlock and reference drop of lle 
Found by: pho
2008-12-24 05:31:26 +00:00

806 lines
22 KiB
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/*-
* 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 "opt_mac.h"
#include "opt_carp.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 <sys/vimage.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/route.h>
#include <net/netisr.h>
#include <net/if_llc.h>
#include <net/ethernet.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <net/if_llatbl.h>
#include <netinet/if_ether.h>
#include <netinet/vinet.h>
#include <net/if_arc.h>
#include <net/iso88025.h>
#ifdef DEV_CARP
#include <netinet/ip_carp.h>
#endif
#include <security/mac/mac_framework.h>
#define SIN(s) ((struct sockaddr_in *)s)
#define SDL(s) ((struct sockaddr_dl *)s)
#define LLTABLE(ifp) ((struct lltable *)(ifp)->if_afdata[AF_INET])
SYSCTL_DECL(_net_link_ether);
SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
/* timer values */
#ifdef VIMAGE_GLOBALS
static int arpt_keep; /* once resolved, good for 20 more minutes */
static int arp_maxtries;
int useloopback; /* use loopback interface for local traffic */
static int arp_proxyall;
#endif
SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, max_age,
CTLFLAG_RW, arpt_keep, 0, "ARP entry lifetime in seconds");
static struct ifqueue arpintrq;
SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, maxtries,
CTLFLAG_RW, arp_maxtries, 0,
"ARP resolution attempts before returning error");
SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, useloopback,
CTLFLAG_RW, useloopback, 0,
"Use the loopback interface for local traffic");
SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, proxyall,
CTLFLAG_RW, arp_proxyall, 0,
"Enable proxy ARP for all suitable requests");
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
#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;
IF_AFDATA_LOCK(ifp);
lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR),
(struct sockaddr *)&addr4);
IF_AFDATA_UNLOCK(ifp);
}
#endif
/*
* Timeout routine. Age arp_tab entries periodically.
*/
static void
arptimer(void *arg)
{
struct ifnet *ifp;
struct llentry *lle = (struct llentry *)arg;
if (lle == NULL) {
panic("%s: NULL entry!\n", __func__);
return;
}
ifp = lle->lle_tbl->llt_ifp;
IF_AFDATA_LOCK(ifp);
LLE_WLOCK(lle);
if (((lle->la_flags & LLE_DELETED)
|| (time_second >= lle->la_expire))
&& (!callout_pending(&lle->la_timer) &&
callout_active(&lle->la_timer)))
(void) llentry_free(lle);
else {
/*
* Still valid, just drop our reference
*/
LLE_FREE_LOCKED(lle);
}
IF_AFDATA_UNLOCK(ifp);
}
/*
* 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, (struct rtentry *)0);
}
/*
* 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)
{
INIT_VNET_INET(ifp->if_vnet);
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_uptime)) {
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_uptime + 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_uptime);
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);
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->rt_flags & RTF_GATEWAY) ? EHOSTDOWN : EHOSTUNREACH;
if (renew) {
LLE_ADDREF(la);
la->la_expire = time_uptime;
callout_reset(&la->la_timer, hz, arptimer, 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 *);
}
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 sockaddr sa;
struct in_addr isaddr, itaddr, myaddr;
u_int8_t *enaddr = NULL;
int op, flags;
struct mbuf *m0;
int req_len;
int bridged = 0, is_bridge = 0;
#ifdef DEV_CARP
int carp_match = 0;
#endif
struct sockaddr_in sin;
sin.sin_len = sizeof(struct sockaddr_in);
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = 0;
INIT_VNET_INET(ifp->if_vnet);
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));
/*
* 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!
*/
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)
goto match;
#ifdef DEV_CARP
if (ifp->if_carp != NULL &&
carp_iamatch(ifp->if_carp, ia, &isaddr, &enaddr) &&
itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
carp_match = 1;
goto match;
}
#endif
}
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)
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)) {
ifp = ia->ia_ifp;
goto match;
}
}
}
#undef BDG_MEMBER_MATCHES_ARP
/*
* No match, use the first inet address on the receive interface
* as a dummy address for the rest of the function.
*/
TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
if (ifa->ifa_addr->sa_family == AF_INET) {
ia = ifatoia(ifa);
goto match;
}
/*
* If bridging, fall back to using any inet address.
*/
if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL)
goto drop;
match:
if (!enaddr)
enaddr = (u_int8_t *)IF_LLADDR(ifp);
myaddr = ia->ia_addr.sin_addr;
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;
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
#ifdef DEV_CARP
&& (ifp->if_type != IFT_CARP || !carp_match)
#endif
) {
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);
goto reply;
}
if ((la->la_flags & LLE_VALID) &&
bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
if (la->la_flags & LLE_STATIC) {
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) {
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;
if (!(la->la_flags & LLE_STATIC)) {
la->la_expire = time_uptime + V_arpt_keep;
callout_reset(&la->la_timer, hz * V_arpt_keep,
arptimer, la);
}
la->la_asked = 0;
la->la_preempt = V_arp_maxtries;
if (la->la_hold != NULL) {
m0 = la->la_hold;
la->la_hold = 0;
memcpy(&sa, L3_ADDR(la), sizeof(sa));
LLE_WUNLOCK(la);
(*ifp->if_output)(ifp, m0, &sa, NULL);
return;
}
}
reply:
if (op != ARPOP_REQUEST)
goto drop;
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;
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;
}
IF_AFDATA_LOCK(rt->rt_ifp);
lle = lla_lookup(LLTABLE(rt->rt_ifp), 0, (struct sockaddr *)&sin);
IF_AFDATA_UNLOCK(rt->rt_ifp);
RTFREE_LOCKED(rt);
if (lle != NULL) {
(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
goto drop;
/*
* 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 (la != NULL)
LLE_WUNLOCK(la);
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, (struct rtentry *)0);
return;
drop:
if (la != NULL)
LLE_WUNLOCK(la);
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)
{
INIT_VNET_INET(curvnet);
V_arpt_keep = (20*60); /* once resolved, good for 20 more minutes */
V_arp_maxtries = 5;
V_useloopback = 1; /* use loopback interface for local traffic */
V_arp_proxyall = 0;
arpintrq.ifq_maxlen = 50;
mtx_init(&arpintrq.ifq_mtx, "arp_inq", NULL, MTX_DEF);
netisr_register(NETISR_ARP, arpintr, &arpintrq, 0);
}
SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);
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