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NetBSD/sys/netinet/if_arp.c

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/* $NetBSD: if_arp.c,v 1.311 2022/11/15 10:47:39 roy Exp $ */
/*
* Copyright (c) 1998, 2000, 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Public Access Networks Corporation ("Panix"). It was developed under
* contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*
* 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.
* 3. 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 8.2 (Berkeley) 9/26/94
*/
/*
* Ethernet address resolution protocol.
* TODO:
* add "inuse/lock" bit (or ref. count) along with valid bit
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: if_arp.c,v 1.311 2022/11/15 10:47:39 roy Exp $");
#ifdef _KERNEL_OPT
#include "opt_ddb.h"
#include "opt_inet.h"
#include "opt_net_mpsafe.h"
#endif
#ifdef INET
#include "arp.h"
#include "bridge.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/kmem.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/timetc.h>
#include <sys/kernel.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/syslog.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/domain.h>
#include <sys/sysctl.h>
#include <sys/socketvar.h>
#include <sys/percpu.h>
#include <sys/cprng.h>
#include <sys/kmem.h>
#include <net/ethertypes.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/if_ether.h>
#include <net/if_llatbl.h>
#include <net/nd.h>
#include <net/route.h>
#include <net/net_stats.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/if_inarp.h>
#include "arcnet.h"
#if NARCNET > 0
#include <net/if_arc.h>
#endif
#include "carp.h"
#if NCARP > 0
#include <netinet/ip_carp.h>
#endif
/*
* ARP trailer negotiation. Trailer protocol is not IP specific,
* but ARP request/response use IP addresses.
*/
#define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL
/* timers */
static int arp_reachable = REACHABLE_TIME;
static int arp_retrans = RETRANS_TIMER;
static int arp_perform_nud = 1;
static bool arp_nud_enabled(struct ifnet *);
static unsigned int arp_llinfo_reachable(struct ifnet *);
static unsigned int arp_llinfo_retrans(struct ifnet *);
static union l3addr *arp_llinfo_holdsrc(struct llentry *, union l3addr *);
static void arp_llinfo_output(struct ifnet *, const union l3addr *,
const union l3addr *, const uint8_t *, const union l3addr *);
static void arp_llinfo_missed(struct ifnet *, const union l3addr *,
int16_t, struct mbuf *);
static void arp_free(struct llentry *, int);
static struct nd_domain arp_nd_domain = {
.nd_family = AF_INET,
.nd_delay = 5, /* delay first probe time 5 second */
.nd_mmaxtries = 3, /* maximum broadcast query */
.nd_umaxtries = 3, /* maximum unicast query */
.nd_retransmultiple = BACKOFF_MULTIPLE,
.nd_maxretrans = MAX_RETRANS_TIMER,
.nd_maxnudhint = 0, /* max # of subsequent upper layer hints */
.nd_maxqueuelen = 1, /* max # of packets in unresolved ND entries */
.nd_nud_enabled = arp_nud_enabled,
.nd_reachable = arp_llinfo_reachable,
.nd_retrans = arp_llinfo_retrans,
.nd_holdsrc = arp_llinfo_holdsrc,
.nd_output = arp_llinfo_output,
.nd_missed = arp_llinfo_missed,
.nd_free = arp_free,
};
int ip_dad_count = PROBE_NUM;
#ifdef ARP_DEBUG
int arp_debug = 1;
#else
int arp_debug = 0;
#endif
static void arp_init(void);
static void arp_dad_init(void);
static void arprequest(struct ifnet *,
const struct in_addr *, const struct in_addr *,
const uint8_t *, const uint8_t *);
static void arpannounce1(struct ifaddr *);
static struct sockaddr *arp_setgate(struct rtentry *, struct sockaddr *,
const struct sockaddr *);
static struct llentry *arpcreate(struct ifnet *,
const struct in_addr *, const struct sockaddr *, int);
static void in_arpinput(struct mbuf *);
static void in_revarpinput(struct mbuf *);
static void revarprequest(struct ifnet *);
static void arp_drainstub(void);
struct dadq;
static void arp_dad_timer(struct dadq *);
static void arp_dad_start(struct ifaddr *);
static void arp_dad_stop(struct ifaddr *);
static void arp_dad_duplicated(struct ifaddr *, const struct sockaddr_dl *);
#define ARP_MAXQLEN 50
pktqueue_t * arp_pktq __read_mostly;
static int useloopback = 1; /* use loopback interface for local traffic */
static percpu_t *arpstat_percpu;
#define ARP_STAT_GETREF() _NET_STAT_GETREF(arpstat_percpu)
#define ARP_STAT_PUTREF() _NET_STAT_PUTREF(arpstat_percpu)
#define ARP_STATINC(x) _NET_STATINC(arpstat_percpu, x)
#define ARP_STATADD(x, v) _NET_STATADD(arpstat_percpu, x, v)
/* revarp state */
static struct in_addr myip, srv_ip;
static int myip_initialized = 0;
static int revarp_in_progress = 0;
static struct ifnet *myip_ifp = NULL;
static int arp_drainwanted;
static int log_movements = 0;
static int log_permanent_modify = 1;
static int log_wrong_iface = 1;
DOMAIN_DEFINE(arpdomain); /* forward declare and add to link set */
static void
arp_fasttimo(void)
{
if (arp_drainwanted) {
arp_drain();
arp_drainwanted = 0;
}
}
static const struct protosw arpsw[] = {
{
.pr_type = 0,
.pr_domain = &arpdomain,
.pr_protocol = 0,
.pr_flags = 0,
.pr_input = 0,
.pr_ctlinput = 0,
.pr_ctloutput = 0,
.pr_usrreqs = 0,
.pr_init = arp_init,
.pr_fasttimo = arp_fasttimo,
.pr_slowtimo = 0,
.pr_drain = arp_drainstub,
}
};
struct domain arpdomain = {
.dom_family = PF_ARP,
.dom_name = "arp",
.dom_protosw = arpsw,
.dom_protoswNPROTOSW = &arpsw[__arraycount(arpsw)],
#ifdef MBUFTRACE
.dom_mowner = MOWNER_INIT("internet", "arp"),
#endif
};
static void sysctl_net_inet_arp_setup(struct sysctllog **);
void
arp_init(void)
{
arp_pktq = pktq_create(ARP_MAXQLEN, arpintr, NULL);
KASSERT(arp_pktq != NULL);
sysctl_net_inet_arp_setup(NULL);
arpstat_percpu = percpu_alloc(sizeof(uint64_t) * ARP_NSTATS);
#ifdef MBUFTRACE
MOWNER_ATTACH(&arpdomain.dom_mowner);
#endif
nd_attach_domain(&arp_nd_domain);
arp_dad_init();
}
static void
arp_drainstub(void)
{
arp_drainwanted = 1;
}
/*
* ARP protocol drain routine. Called when memory is in short supply.
* Called at splvm(); don't acquire softnet_lock as can be called from
* hardware interrupt handlers.
*/
void
arp_drain(void)
{
lltable_drain(AF_INET);
}
/*
* We set the gateway for RTF_CLONING routes to a "prototype"
* link-layer sockaddr whose interface type (if_type) and interface
* index (if_index) fields are prepared.
*/
static struct sockaddr *
arp_setgate(struct rtentry *rt, struct sockaddr *gate,
const struct sockaddr *netmask)
{
const struct ifnet *ifp = rt->rt_ifp;
uint8_t namelen = strlen(ifp->if_xname);
uint8_t addrlen = ifp->if_addrlen;
/*
* XXX: If this is a manually added route to interface
* such as older version of routed or gated might provide,
* restore cloning bit.
*/
if ((rt->rt_flags & RTF_HOST) == 0 && netmask != NULL &&
satocsin(netmask)->sin_addr.s_addr != 0xffffffff)
rt->rt_flags |= RTF_CONNECTED;
if ((rt->rt_flags & (RTF_CONNECTED | RTF_LOCAL))) {
union {
struct sockaddr sa;
struct sockaddr_storage ss;
struct sockaddr_dl sdl;
} u;
/*
* Case 1: This route should come from a route to iface.
*/
sockaddr_dl_init(&u.sdl, sizeof(u.ss),
ifp->if_index, ifp->if_type, NULL, namelen, NULL, addrlen);
rt_setgate(rt, &u.sa);
gate = rt->rt_gateway;
}
return gate;
}
/*
* Parallel to llc_rtrequest.
*/
void
arp_rtrequest(int req, struct rtentry *rt, const struct rt_addrinfo *info)
{
struct sockaddr *gate = rt->rt_gateway;
struct in_ifaddr *ia;
struct ifaddr *ifa;
struct ifnet *ifp = rt->rt_ifp;
int bound;
int s;
if (req == RTM_LLINFO_UPD) {
if ((ifa = info->rti_ifa) != NULL)
arpannounce1(ifa);
return;
}
if ((rt->rt_flags & RTF_GATEWAY) != 0) {
if (req != RTM_ADD)
return;
/*
* linklayers with particular link MTU limitation.
*/
switch(ifp->if_type) {
#if NARCNET > 0
case IFT_ARCNET:
{
int arcipifmtu;
if (ifp->if_flags & IFF_LINK0)
arcipifmtu = arc_ipmtu;
else
arcipifmtu = ARCMTU;
if (ifp->if_mtu > arcipifmtu)
rt->rt_rmx.rmx_mtu = arcipifmtu;
break;
}
#endif
}
return;
}
switch (req) {
case RTM_SETGATE:
gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]);
break;
case RTM_ADD:
gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]);
if (gate == NULL) {
log(LOG_ERR, "%s: arp_setgate failed\n", __func__);
break;
}
if ((rt->rt_flags & RTF_CONNECTED) ||
(rt->rt_flags & RTF_LOCAL)) {
/*
* linklayers with particular link MTU limitation.
*/
switch (ifp->if_type) {
#if NARCNET > 0
case IFT_ARCNET:
{
int arcipifmtu;
if (ifp->if_flags & IFF_LINK0)
arcipifmtu = arc_ipmtu;
else
arcipifmtu = ARCMTU;
if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 &&
(rt->rt_rmx.rmx_mtu > arcipifmtu ||
(rt->rt_rmx.rmx_mtu == 0 &&
ifp->if_mtu > arcipifmtu)))
rt->rt_rmx.rmx_mtu = arcipifmtu;
break;
}
#endif
}
if (rt->rt_flags & RTF_CONNECTED)
break;
}
bound = curlwp_bind();
/* Announce a new entry if requested. */
if (rt->rt_flags & RTF_ANNOUNCE) {
struct psref psref;
ia = in_get_ia_on_iface_psref(
satocsin(rt_getkey(rt))->sin_addr, ifp, &psref);
if (ia != NULL) {
arpannounce(ifp, &ia->ia_ifa,
CLLADDR(satocsdl(gate)));
ia4_release(ia, &psref);
}
}
if (gate->sa_family != AF_LINK ||
gate->sa_len < sockaddr_dl_measure(0, ifp->if_addrlen)) {
log(LOG_DEBUG, "%s: bad gateway value\n", __func__);
goto out;
}
satosdl(gate)->sdl_type = ifp->if_type;
satosdl(gate)->sdl_index = ifp->if_index;
/*
* If the route is for a broadcast address mark it as such.
* This way we can avoid an expensive call to in_broadcast()
* in ip_output() most of the time (because the route passed
* to ip_output() is almost always a host route).
*/
if (rt->rt_flags & RTF_HOST &&
!(rt->rt_flags & RTF_BROADCAST) &&
in_broadcast(satocsin(rt_getkey(rt))->sin_addr, rt->rt_ifp))
rt->rt_flags |= RTF_BROADCAST;
/* There is little point in resolving the broadcast address */
if (rt->rt_flags & RTF_BROADCAST)
goto out;
/*
* When called from rt_ifa_addlocal, we cannot depend on that
* the address (rt_getkey(rt)) exits in the address list of the
* interface. So check RTF_LOCAL instead.
*/
if (rt->rt_flags & RTF_LOCAL) {
if (useloopback) {
rt->rt_ifp = lo0ifp;
rt->rt_rmx.rmx_mtu = 0;
}
goto out;
}
s = pserialize_read_enter();
ia = in_get_ia_on_iface(satocsin(rt_getkey(rt))->sin_addr, ifp);
if (ia == NULL) {
pserialize_read_exit(s);
goto out;
}
if (useloopback) {
rt->rt_ifp = lo0ifp;
rt->rt_rmx.rmx_mtu = 0;
}
rt->rt_flags |= RTF_LOCAL;
if (ISSET(info->rti_flags, RTF_DONTCHANGEIFA)) {
pserialize_read_exit(s);
goto out;
}
/*
* make sure to set rt->rt_ifa to the interface
* address we are using, otherwise we will have trouble
* with source address selection.
*/
ifa = &ia->ia_ifa;
if (ifa != rt->rt_ifa)
/* Assume it doesn't sleep */
rt_replace_ifa(rt, ifa);
pserialize_read_exit(s);
out:
curlwp_bindx(bound);
break;
}
}
/*
* Broadcast an ARP request. Caller specifies:
* - arp header source ip address
* - arp header target ip address
* - arp header source ethernet address
*/
static void
arprequest(struct ifnet *ifp,
const struct in_addr *sip, const struct in_addr *tip,
const uint8_t *saddr, const uint8_t *taddr)
{
struct mbuf *m;
struct arphdr *ah;
struct sockaddr sa;
uint64_t *arps;
KASSERT(sip != NULL);
KASSERT(tip != NULL);
KASSERT(saddr != NULL);
if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
return;
MCLAIM(m, &arpdomain.dom_mowner);
switch (ifp->if_type) {
case IFT_IEEE1394:
m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) +
ifp->if_addrlen;
break;
default:
m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) +
2 * ifp->if_addrlen;
break;
}
m->m_pkthdr.len = m->m_len;
m_align(m, m->m_len);
ah = mtod(m, struct arphdr *);
memset(ah, 0, m->m_len);
switch (ifp->if_type) {
case IFT_IEEE1394: /* RFC2734 */
/* fill it now for ar_tpa computation */
ah->ar_hrd = htons(ARPHRD_IEEE1394);
break;
default:
/* ifp->if_output will fill ar_hrd */
break;
}
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);
memcpy(ar_sha(ah), saddr, ah->ar_hln);
if (taddr == NULL)
m->m_flags |= M_BCAST;
else
memcpy(ar_tha(ah), taddr, ah->ar_hln);
memcpy(ar_spa(ah), sip, ah->ar_pln);
memcpy(ar_tpa(ah), tip, ah->ar_pln);
sa.sa_family = AF_ARP;
sa.sa_len = 2;
arps = ARP_STAT_GETREF();
arps[ARP_STAT_SNDTOTAL]++;
arps[ARP_STAT_SENDREQUEST]++;
ARP_STAT_PUTREF();
if_output_lock(ifp, ifp, m, &sa, NULL);
}
void
arpannounce(struct ifnet *ifp, struct ifaddr *ifa, const uint8_t *enaddr)
{
struct in_ifaddr *ia = ifatoia(ifa);
struct in_addr *ip = &IA_SIN(ifa)->sin_addr;
if (ia->ia4_flags & (IN_IFF_NOTREADY | IN_IFF_DETACHED)) {
ARPLOG(LOG_DEBUG, "%s not ready\n", ARPLOGADDR(ip));
return;
}
arprequest(ifp, ip, ip, enaddr, NULL);
}
static void
arpannounce1(struct ifaddr *ifa)
{
arpannounce(ifa->ifa_ifp, ifa, CLLADDR(ifa->ifa_ifp->if_sadl));
}
/*
* Resolve an IP address into an ethernet address. If success, desten is
* filled in. If there is no entry in arptab, set one up and broadcast a
* request for the IP address. Hold onto this mbuf and resend it once the
* address is finally resolved.
*
* A return value of 0 indicates that desten has been filled in and the packet
* should be sent normally; a return value of EWOULDBLOCK indicates that the
* packet has been held pending resolution. Any other value indicates an
* error.
*/
int
arpresolve(struct ifnet *ifp, const struct rtentry *rt, struct mbuf *m,
const struct sockaddr *dst, void *desten, size_t destlen)
{
struct llentry *la;
const char *create_lookup;
int error;
#if NCARP > 0
if (rt != NULL && rt->rt_ifp->if_type == IFT_CARP)
ifp = rt->rt_ifp;
#endif
KASSERT(m != NULL);
la = arplookup(ifp, NULL, dst, 0);
if (la == NULL)
goto notfound;
if (la->la_flags & LLE_VALID && la->ln_state == ND_LLINFO_REACHABLE) {
KASSERT(destlen >= ifp->if_addrlen);
memcpy(desten, &la->ll_addr, ifp->if_addrlen);
LLE_RUNLOCK(la);
return 0;
}
notfound:
if (ifp->if_flags & IFF_NOARP) {
if (la != NULL)
LLE_RUNLOCK(la);
error = ENOTSUP;
goto bad;
}
if (la == NULL) {
struct rtentry *_rt;
create_lookup = "create";
_rt = rtalloc1(dst, 0);
IF_AFDATA_WLOCK(ifp);
la = lla_create(LLTABLE(ifp), LLE_EXCLUSIVE, dst, _rt);
IF_AFDATA_WUNLOCK(ifp);
if (_rt != NULL)
rt_unref(_rt);
if (la == NULL)
ARP_STATINC(ARP_STAT_ALLOCFAIL);
else
la->ln_state = ND_LLINFO_NOSTATE;
} else if (LLE_TRY_UPGRADE(la) == 0) {
create_lookup = "lookup";
LLE_RUNLOCK(la);
IF_AFDATA_RLOCK(ifp);
la = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst);
IF_AFDATA_RUNLOCK(ifp);
}
error = EINVAL;
if (la == NULL) {
log(LOG_DEBUG,
"%s: failed to %s llentry for %s on %s\n",
__func__, create_lookup, inet_ntoa(satocsin(dst)->sin_addr),
ifp->if_xname);
goto bad;
}
error = nd_resolve(la, rt, m, desten, destlen);
return error;
bad:
m_freem(m);
return error;
}
/*
* Common length and type checks are done here,
* then the protocol-specific routine is called.
*/
void
arpintr(void *arg __unused)
{
struct mbuf *m;
struct arphdr *ar;
int s;
int arplen;
struct ifnet *rcvif;
bool badhrd;
SOFTNET_KERNEL_LOCK_UNLESS_NET_MPSAFE();
while ((m = pktq_dequeue(arp_pktq)) != NULL) {
if ((m->m_flags & M_PKTHDR) == 0)
panic("arpintr");
MCLAIM(m, &arpdomain.dom_mowner);
ARP_STATINC(ARP_STAT_RCVTOTAL);
if (__predict_false(m->m_len < sizeof(*ar))) {
if ((m = m_pullup(m, sizeof(*ar))) == NULL)
goto badlen;
}
ar = mtod(m, struct arphdr *);
KASSERT(ACCESSIBLE_POINTER(ar, struct arphdr));
rcvif = m_get_rcvif(m, &s);
if (__predict_false(rcvif == NULL)) {
ARP_STATINC(ARP_STAT_RCVNOINT);
goto free;
}
/*
* We don't want non-IEEE1394 ARP packets on IEEE1394
* interfaces, and vice versa. Our life depends on that.
*/
if (ntohs(ar->ar_hrd) == ARPHRD_IEEE1394)
badhrd = rcvif->if_type != IFT_IEEE1394;
else
badhrd = rcvif->if_type == IFT_IEEE1394;
m_put_rcvif(rcvif, &s);
if (badhrd) {
ARP_STATINC(ARP_STAT_RCVBADPROTO);
goto free;
}
arplen = sizeof(*ar) + 2 * ar->ar_hln + 2 * ar->ar_pln;
if (__predict_false(m->m_len < arplen)) {
if ((m = m_pullup(m, arplen)) == NULL)
goto badlen;
ar = mtod(m, struct arphdr *);
KASSERT(ACCESSIBLE_POINTER(ar, struct arphdr));
}
switch (ntohs(ar->ar_pro)) {
case ETHERTYPE_IP:
case ETHERTYPE_IPTRAILERS:
in_arpinput(m);
continue;
default:
ARP_STATINC(ARP_STAT_RCVBADPROTO);
goto free;
}
badlen:
ARP_STATINC(ARP_STAT_RCVBADLEN);
free:
m_freem(m);
}
SOFTNET_KERNEL_UNLOCK_UNLESS_NET_MPSAFE();
return; /* XXX gcc */
}
/*
* 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 void
in_arpinput(struct mbuf *m)
{
struct arphdr *ah;
struct ifnet *ifp, *rcvif = NULL;
struct llentry *la = NULL;
struct in_ifaddr *ia = NULL;
#if NBRIDGE > 0
struct in_ifaddr *bridge_ia = NULL;
#endif
#if NCARP > 0
uint32_t count = 0, index = 0;
#endif
struct sockaddr sa;
struct in_addr isaddr, itaddr, myaddr;
int op, rt_cmd, new_state = 0;
void *tha;
uint64_t *arps;
struct psref psref, psref_ia;
int s;
char ipbuf[INET_ADDRSTRLEN];
bool find_source, do_dad;
if (__predict_false(m_makewritable(&m, 0, m->m_pkthdr.len, M_DONTWAIT)))
goto out;
ah = mtod(m, struct arphdr *);
op = ntohs(ah->ar_op);
if (ah->ar_pln != sizeof(struct in_addr))
goto out;
ifp = if_get_bylla(ar_sha(ah), ah->ar_hln, &psref);
if (ifp) {
/* it's from me, ignore it. */
if_put(ifp, &psref);
ARP_STATINC(ARP_STAT_RCVLOCALSHA);
goto out;
}
rcvif = ifp = m_get_rcvif_psref(m, &psref);
if (__predict_false(rcvif == NULL))
goto out;
if (rcvif->if_flags & IFF_NOARP)
goto out;
memcpy(&isaddr, ar_spa(ah), sizeof(isaddr));
memcpy(&itaddr, ar_tpa(ah), sizeof(itaddr));
if (m->m_flags & (M_BCAST|M_MCAST))
ARP_STATINC(ARP_STAT_RCVMCAST);
/*
* Search for a matching interface address
* or any address on the interface to use
* as a dummy address in the rest of this function.
*
* First try and find the source address for early
* duplicate address detection.
*/
if (in_nullhost(isaddr)) {
if (in_nullhost(itaddr)) /* very bogus ARP */
goto out;
find_source = false;
myaddr = itaddr;
} else {
find_source = true;
myaddr = isaddr;
}
s = pserialize_read_enter();
again:
IN_ADDRHASH_READER_FOREACH(ia, myaddr.s_addr) {
if (!in_hosteq(ia->ia_addr.sin_addr, myaddr))
continue;
#if NCARP > 0
if (ia->ia_ifp->if_type == IFT_CARP &&
((ia->ia_ifp->if_flags & (IFF_UP|IFF_RUNNING)) ==
(IFF_UP|IFF_RUNNING))) {
index++;
/* XXX: ar_hln? */
if (ia->ia_ifp == rcvif && (ah->ar_hln >= 6) &&
carp_iamatch(ia, ar_sha(ah),
&count, index)) {
break;
}
} else
#endif
if (ia->ia_ifp == rcvif)
break;
#if NBRIDGE > 0
/*
* If the interface we received the packet on
* is part of a bridge, check to see if we need
* to "bridge" the packet to ourselves at this
* layer. Note we still prefer a perfect match,
* but allow this weaker match if necessary.
*/
if (rcvif->if_bridge != NULL &&
rcvif->if_bridge == ia->ia_ifp->if_bridge)
bridge_ia = ia;
#endif
}
#if NBRIDGE > 0
if (ia == NULL && bridge_ia != NULL) {
ia = bridge_ia;
m_put_rcvif_psref(rcvif, &psref);
rcvif = NULL;
/* FIXME */
ifp = bridge_ia->ia_ifp;
}
#endif
/* If we failed to find the source address then find
* the target address. */
if (ia == NULL && find_source && !in_nullhost(itaddr)) {
find_source = false;
myaddr = itaddr;
goto again;
}
if (ia != NULL)
ia4_acquire(ia, &psref_ia);
pserialize_read_exit(s);
if (ah->ar_hln != ifp->if_addrlen) {
ARP_STATINC(ARP_STAT_RCVBADLEN);
log(LOG_WARNING,
"arp from %s: addr len: new %d, i/f %d (ignored)\n",
IN_PRINT(ipbuf, &isaddr), ah->ar_hln, ifp->if_addrlen);
goto out;
}
/* Only do DaD if we have a matching address. */
do_dad = (ia != NULL);
if (ia == NULL) {
ia = in_get_ia_on_iface_psref(isaddr, rcvif, &psref_ia);
if (ia == NULL) {
ia = in_get_ia_from_ifp_psref(ifp, &psref_ia);
if (ia == NULL) {
ARP_STATINC(ARP_STAT_RCVNOINT);
goto out;
}
}
}
myaddr = ia->ia_addr.sin_addr;
/* XXX checks for bridge case? */
if (!memcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
ARP_STATINC(ARP_STAT_RCVBCASTSHA);
log(LOG_ERR,
"%s: arp: link address is broadcast for IP address %s!\n",
ifp->if_xname, IN_PRINT(ipbuf, &isaddr));
goto out;
}
/*
* If the source IP address is zero, this is an RFC 5227 ARP probe
*/
if (in_nullhost(isaddr))
ARP_STATINC(ARP_STAT_RCVZEROSPA);
else if (in_hosteq(isaddr, myaddr))
ARP_STATINC(ARP_STAT_RCVLOCALSPA);
if (in_nullhost(itaddr))
ARP_STATINC(ARP_STAT_RCVZEROTPA);
/*
* DAD check, RFC 5227.
* ARP sender hardware address must match the interface
* address of the interface sending the packet.
* Collision on sender address is always a duplicate.
* Collision on target address is only a duplicate
* IF the sender address is the null host (ie a DAD probe)
* AND the message was broadcast
* AND our address is either tentative or duplicated
* If it was unicast then it's a valid Unicast Poll from RFC 1122.
*/
if (do_dad &&
(in_hosteq(isaddr, myaddr) ||
(in_nullhost(isaddr) && in_hosteq(itaddr, myaddr) &&
m->m_flags & M_BCAST &&
ia->ia4_flags & (IN_IFF_TENTATIVE | IN_IFF_DUPLICATED))))
{
struct m_tag *mtag;
mtag = m_tag_find(m, PACKET_TAG_ETHERNET_SRC);
if (mtag == NULL || (ah->ar_hln == ETHER_ADDR_LEN &&
memcmp(mtag + 1, ar_sha(ah), ah->ar_hln) == 0)) {
struct sockaddr_dl sdl, *sdlp;
sdlp = sockaddr_dl_init(&sdl, sizeof(sdl),
ifp->if_index, ifp->if_type,
NULL, 0, ar_sha(ah), ah->ar_hln);
arp_dad_duplicated((struct ifaddr *)ia, sdlp);
goto out;
}
}
/*
* If the target IP address is zero, ignore the packet.
* This prevents the code below from trying to answer
* when we are using IP address zero (booting).
*/
if (in_nullhost(itaddr))
goto out;
if (in_nullhost(isaddr))
goto reply;
if (in_hosteq(itaddr, myaddr))
la = arpcreate(ifp, &isaddr, NULL, 1);
else
la = arplookup(ifp, &isaddr, NULL, 1);
if (la == NULL)
goto reply;
if ((la->la_flags & LLE_VALID) &&
memcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen))
{
char llabuf[LLA_ADDRSTRLEN], *llastr;
llastr = lla_snprintf(llabuf, sizeof(llabuf),
ar_sha(ah), ah->ar_hln);
if (la->la_flags & LLE_STATIC) {
ARP_STATINC(ARP_STAT_RCVOVERPERM);
if (!log_permanent_modify)
goto out;
log(LOG_INFO,
"%s tried to overwrite permanent arp info"
" for %s\n", llastr, IN_PRINT(ipbuf, &isaddr));
goto out;
} else if (la->lle_tbl->llt_ifp != ifp) {
/* XXX should not happen? */
ARP_STATINC(ARP_STAT_RCVOVERINT);
if (!log_wrong_iface)
goto out;
log(LOG_INFO,
"%s on %s tried to overwrite "
"arp info for %s on %s\n",
llastr,
ifp->if_xname, IN_PRINT(ipbuf, &isaddr),
la->lle_tbl->llt_ifp->if_xname);
goto out;
} else {
ARP_STATINC(ARP_STAT_RCVOVER);
if (log_movements)
log(LOG_INFO, "arp info overwritten "
"for %s by %s\n",
IN_PRINT(ipbuf, &isaddr), llastr);
}
rt_cmd = RTM_CHANGE;
new_state = ND_LLINFO_STALE;
} else {
if (op == ARPOP_REPLY && in_hosteq(itaddr, myaddr)) {
/* This was a solicited ARP reply. */
la->ln_byhint = 0;
new_state = ND_LLINFO_REACHABLE;
}
rt_cmd = la->la_flags & LLE_VALID ? 0 : RTM_ADD;
}
KASSERT(ifp->if_sadl->sdl_alen == ifp->if_addrlen);
KASSERT(sizeof(la->ll_addr) >= ifp->if_addrlen);
memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
la->la_flags |= LLE_VALID;
la->ln_asked = 0;
if (new_state != 0) {
la->ln_state = new_state;
if (new_state != ND_LLINFO_REACHABLE ||
!(la->la_flags & LLE_STATIC))
{
int timer = ND_TIMER_GC;
if (new_state == ND_LLINFO_REACHABLE)
timer = ND_TIMER_REACHABLE;
nd_set_timer(la, timer);
}
}
if (rt_cmd != 0) {
struct sockaddr_in sin;
sockaddr_in_init(&sin, &la->r_l3addr.addr4, 0);
rt_clonedmsg(rt_cmd, NULL, sintosa(&sin), ar_sha(ah), ifp);
}
if (la->la_hold != NULL) {
int n = la->la_numheld;
struct mbuf *m_hold, *m_hold_next;
struct sockaddr_in sin;
sockaddr_in_init(&sin, &la->r_l3addr.addr4, 0);
m_hold = la->la_hold;
la->la_hold = NULL;
la->la_numheld = 0;
/*
* We have to unlock here because if_output would call
* arpresolve
*/
LLE_WUNLOCK(la);
ARP_STATADD(ARP_STAT_DFRSENT, n);
ARP_STATADD(ARP_STAT_DFRTOTAL, n);
for (; m_hold != NULL; m_hold = m_hold_next) {
m_hold_next = m_hold->m_nextpkt;
m_hold->m_nextpkt = NULL;
if_output_lock(ifp, ifp, m_hold, sintosa(&sin), NULL);
}
} else
LLE_WUNLOCK(la);
la = NULL;
reply:
if (la != NULL) {
LLE_WUNLOCK(la);
la = NULL;
}
if (op != ARPOP_REQUEST) {
if (op == ARPOP_REPLY)
ARP_STATINC(ARP_STAT_RCVREPLY);
goto out;
}
ARP_STATINC(ARP_STAT_RCVREQUEST);
if (in_hosteq(itaddr, myaddr)) {
/* If our address is unusable, don't reply */
if (ia->ia4_flags & (IN_IFF_NOTREADY | IN_IFF_DETACHED))
goto out;
/* I am the target */
tha = ar_tha(ah);
if (tha)
memcpy(tha, ar_sha(ah), ah->ar_hln);
memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln);
} else {
/* Proxy ARP */
struct llentry *lle = NULL;
struct sockaddr_in sin;
#if NCARP > 0
if (ifp->if_type == IFT_CARP) {
struct ifnet *_rcvif = m_get_rcvif(m, &s);
int iftype = 0;
if (__predict_true(_rcvif != NULL))
iftype = _rcvif->if_type;
m_put_rcvif(_rcvif, &s);
if (iftype != IFT_CARP)
goto out;
}
#endif
tha = ar_tha(ah);
sockaddr_in_init(&sin, &itaddr, 0);
IF_AFDATA_RLOCK(ifp);
lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
IF_AFDATA_RUNLOCK(ifp);
if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
if (tha)
memcpy(tha, ar_sha(ah), ah->ar_hln);
memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
LLE_RUNLOCK(lle);
} else {
if (lle != NULL)
LLE_RUNLOCK(lle);
goto out;
}
}
ia4_release(ia, &psref_ia);
/*
* XXX XXX: Here we're recycling the mbuf. But the mbuf could have
* other mbufs in its chain, and just overwriting m->m_pkthdr.len
* would be wrong in this case (the length becomes smaller than the
* real chain size).
*
* This can theoretically cause bugs in the lower layers (drivers,
* and L2encap), in some corner cases.
*/
memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
ah->ar_op = htons(ARPOP_REPLY);
ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
switch (ifp->if_type) {
case IFT_IEEE1394:
/* ieee1394 arp reply is broadcast */
m->m_flags &= ~M_MCAST;
m->m_flags |= M_BCAST;
m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + ah->ar_hln;
break;
default:
m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */
m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
break;
}
m->m_pkthdr.len = m->m_len;
sa.sa_family = AF_ARP;
sa.sa_len = 2;
arps = ARP_STAT_GETREF();
arps[ARP_STAT_SNDTOTAL]++;
arps[ARP_STAT_SNDREPLY]++;
ARP_STAT_PUTREF();
if_output_lock(ifp, ifp, m, &sa, NULL);
if (rcvif != NULL)
m_put_rcvif_psref(rcvif, &psref);
return;
out:
if (la != NULL)
LLE_WUNLOCK(la);
if (ia != NULL)
ia4_release(ia, &psref_ia);
if (rcvif != NULL)
m_put_rcvif_psref(rcvif, &psref);
m_freem(m);
}
/*
* Lookup or a new address in arptab.
*/
struct llentry *
arplookup(struct ifnet *ifp, const struct in_addr *addr,
const struct sockaddr *sa, int wlock)
{
struct sockaddr_in sin;
struct llentry *la;
int flags = wlock ? LLE_EXCLUSIVE : 0;
if (sa == NULL) {
KASSERT(addr != NULL);
sockaddr_in_init(&sin, addr, 0);
sa = sintocsa(&sin);
}
IF_AFDATA_RLOCK(ifp);
la = lla_lookup(LLTABLE(ifp), flags, sa);
IF_AFDATA_RUNLOCK(ifp);
return la;
}
static struct llentry *
arpcreate(struct ifnet *ifp, const struct in_addr *addr,
const struct sockaddr *sa, int wlock)
{
struct sockaddr_in sin;
struct llentry *la;
int flags = wlock ? LLE_EXCLUSIVE : 0;
if (sa == NULL) {
KASSERT(addr != NULL);
sockaddr_in_init(&sin, addr, 0);
sa = sintocsa(&sin);
}
la = arplookup(ifp, addr, sa, wlock);
if (la == NULL) {
struct rtentry *rt;
rt = rtalloc1(sa, 0);
IF_AFDATA_WLOCK(ifp);
la = lla_create(LLTABLE(ifp), flags, sa, rt);
IF_AFDATA_WUNLOCK(ifp);
if (rt != NULL)
rt_unref(rt);
if (la != NULL)
la->ln_state = ND_LLINFO_NOSTATE;
}
return la;
}
int
arpioctl(u_long cmd, void *data)
{
return EOPNOTSUPP;
}
void
arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
{
struct in_ifaddr *ia = (struct in_ifaddr *)ifa;
ifa->ifa_rtrequest = arp_rtrequest;
ifa->ifa_flags |= RTF_CONNECTED;
/* ARP will handle DAD for this address. */
if (in_nullhost(IA_SIN(ifa)->sin_addr)) {
if (ia->ia_dad_stop != NULL) /* safety */
ia->ia_dad_stop(ifa);
ia->ia_dad_start = NULL;
ia->ia_dad_stop = NULL;
ia->ia4_flags &= ~IN_IFF_TENTATIVE;
} else {
ia->ia_dad_start = arp_dad_start;
ia->ia_dad_stop = arp_dad_stop;
if (ia->ia4_flags & IN_IFF_TRYTENTATIVE && ip_dad_enabled())
ia->ia4_flags |= IN_IFF_TENTATIVE;
else
arpannounce1(ifa);
}
}
static bool
arp_nud_enabled(__unused struct ifnet *ifp)
{
return arp_perform_nud != 0;
}
static unsigned int
arp_llinfo_reachable(__unused struct ifnet *ifp)
{
return arp_reachable;
}
static unsigned int
arp_llinfo_retrans(__unused struct ifnet *ifp)
{
return arp_retrans;
}
/*
* Gets source address of the first packet in hold queue
* and stores it in @src.
* Returns pointer to @src (if hold queue is not empty) or NULL.
*/
static union l3addr *
arp_llinfo_holdsrc(struct llentry *ln, union l3addr *src)
{
struct ip *ip;
if (ln == NULL || ln->ln_hold == NULL)
return NULL;
/*
* assuming every packet in ln_hold has the same IP header
*/
ip = mtod(ln->ln_hold, struct ip *);
/* XXX pullup? */
if (sizeof(*ip) < ln->ln_hold->m_len)
src->addr4 = ip->ip_src;
else
src = NULL;
return src;
}
static void
arp_llinfo_output(struct ifnet *ifp, __unused const union l3addr *daddr,
const union l3addr *taddr, const uint8_t *tlladdr,
const union l3addr *hsrc)
{
struct in_addr tip = taddr->addr4, sip = zeroin_addr;
const uint8_t *slladdr = CLLADDR(ifp->if_sadl);
if (hsrc != NULL) {
struct in_ifaddr *ia;
struct psref psref;
ia = in_get_ia_on_iface_psref(hsrc->addr4, ifp, &psref);
if (ia != NULL) {
sip = hsrc->addr4;
ia4_release(ia, &psref);
}
}
if (sip.s_addr == INADDR_ANY) {
struct sockaddr_in dst;
struct rtentry *rt;
sockaddr_in_init(&dst, &tip, 0);
rt = rtalloc1(sintosa(&dst), 0);
if (rt != NULL) {
if (rt->rt_ifp == ifp &&
rt->rt_ifa != NULL &&
rt->rt_ifa->ifa_addr->sa_family == AF_INET)
sip = satosin(rt->rt_ifa->ifa_addr)->sin_addr;
rt_unref(rt);
}
if (sip.s_addr == INADDR_ANY) {
char ipbuf[INET_ADDRSTRLEN];
log(LOG_DEBUG, "source can't be "
"determined: dst=%s\n",
IN_PRINT(ipbuf, &tip));
return;
}
}
arprequest(ifp, &sip, &tip, slladdr, tlladdr);
}
static void
arp_llinfo_missed(struct ifnet *ifp, const union l3addr *taddr,
__unused int16_t type, struct mbuf *m)
{
struct in_addr mdaddr = zeroin_addr;
struct sockaddr_in dsin, tsin;
struct sockaddr *sa;
if (m != NULL) {
struct ip *ip = mtod(m, struct ip *);
if (sizeof(*ip) < m->m_len)
mdaddr = ip->ip_src;
/* ip_input() will send ICMP_UNREACH_HOST, not us. */
m_freem(m);
}
if (mdaddr.s_addr != INADDR_ANY) {
sockaddr_in_init(&dsin, &mdaddr, 0);
sa = sintosa(&dsin);
} else
sa = NULL;
sockaddr_in_init(&tsin, &taddr->addr4, 0);
rt_clonedmsg(RTM_MISS, sa, sintosa(&tsin), NULL, ifp);
}
static void
arp_free(struct llentry *ln, int gc)
{
struct ifnet *ifp;
KASSERT(ln != NULL);
LLE_WLOCK_ASSERT(ln);
ifp = ln->lle_tbl->llt_ifp;
if (ln->la_flags & LLE_VALID || gc) {
struct sockaddr_in sin;
const char *lladdr;
sockaddr_in_init(&sin, &ln->r_l3addr.addr4, 0);
lladdr = ln->la_flags & LLE_VALID ?
(const char *)&ln->ll_addr : NULL;
rt_clonedmsg(RTM_DELETE, NULL, sintosa(&sin), lladdr, ifp);
}
/*
* Save to unlock. We still hold an extra reference and will not
* free(9) in llentry_free() if someone else holds one as well.
*/
LLE_WUNLOCK(ln);
IF_AFDATA_LOCK(ifp);
LLE_WLOCK(ln);
lltable_free_entry(LLTABLE(ifp), ln);
IF_AFDATA_UNLOCK(ifp);
}
/*
* Upper-layer reachability hint for Neighbor Unreachability Detection.
*
* XXX cost-effective methods?
*/
void
arp_nud_hint(struct rtentry *rt)
{
struct llentry *ln;
struct ifnet *ifp;
if (rt == NULL)
return;
ifp = rt->rt_ifp;
ln = arplookup(ifp, NULL, rt_getkey(rt), 1);
nd_nud_hint(ln);
}
TAILQ_HEAD(dadq_head, dadq);
struct dadq {
TAILQ_ENTRY(dadq) dad_list;
struct ifaddr *dad_ifa;
int dad_count; /* max ARP to send */
int dad_arp_tcount; /* # of trials to send ARP */
int dad_arp_ocount; /* ARP sent so far */
int dad_arp_announce; /* max ARP announcements */
int dad_arp_acount; /* # of announcements */
struct callout dad_timer_ch;
};
static struct dadq_head dadq;
static int dad_maxtry = 15; /* max # of *tries* to transmit DAD packet */
static kmutex_t arp_dad_lock;
static void
arp_dad_init(void)
{
TAILQ_INIT(&dadq);
mutex_init(&arp_dad_lock, MUTEX_DEFAULT, IPL_NONE);
}
static struct dadq *
arp_dad_find(struct ifaddr *ifa)
{
struct dadq *dp;
KASSERT(mutex_owned(&arp_dad_lock));
TAILQ_FOREACH(dp, &dadq, dad_list) {
if (dp->dad_ifa == ifa)
return dp;
}
return NULL;
}
static void
arp_dad_starttimer(struct dadq *dp, int ticks)
{
callout_reset(&dp->dad_timer_ch, ticks,
(void (*)(void *))arp_dad_timer, dp);
}
static void
arp_dad_stoptimer(struct dadq *dp)
{
KASSERT(mutex_owned(&arp_dad_lock));
TAILQ_REMOVE(&dadq, dp, dad_list);
/* Tell the timer that dp is being destroyed. */
dp->dad_ifa = NULL;
callout_halt(&dp->dad_timer_ch, &arp_dad_lock);
}
static void
arp_dad_destroytimer(struct dadq *dp)
{
callout_destroy(&dp->dad_timer_ch);
KASSERT(dp->dad_ifa == NULL);
kmem_intr_free(dp, sizeof(*dp));
}
static void
arp_dad_output(struct dadq *dp, struct ifaddr *ifa)
{
struct in_ifaddr *ia = (struct in_ifaddr *)ifa;
struct ifnet *ifp = ifa->ifa_ifp;
struct in_addr sip;
dp->dad_arp_tcount++;
if ((ifp->if_flags & IFF_UP) == 0)
return;
if ((ifp->if_flags & IFF_RUNNING) == 0)
return;
dp->dad_arp_tcount = 0;
dp->dad_arp_ocount++;
memset(&sip, 0, sizeof(sip));
arprequest(ifa->ifa_ifp, &sip, &ia->ia_addr.sin_addr,
CLLADDR(ifa->ifa_ifp->if_sadl), NULL);
}
/*
* Start Duplicate Address Detection (DAD) for specified interface address.
*/
static void
arp_dad_start(struct ifaddr *ifa)
{
struct in_ifaddr *ia = (struct in_ifaddr *)ifa;
struct dadq *dp;
char ipbuf[INET_ADDRSTRLEN];
/*
* If we don't need DAD, don't do it.
* - DAD is disabled
*/
if (!(ia->ia4_flags & IN_IFF_TENTATIVE)) {
log(LOG_DEBUG,
"%s: called with non-tentative address %s(%s)\n", __func__,
IN_PRINT(ipbuf, &ia->ia_addr.sin_addr),
ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
return;
}
if (!ip_dad_enabled()) {
ia->ia4_flags &= ~IN_IFF_TENTATIVE;
rt_addrmsg(RTM_NEWADDR, ifa);
arpannounce1(ifa);
return;
}
KASSERT(ifa->ifa_ifp != NULL);
if (!(ifa->ifa_ifp->if_flags & IFF_UP))
return;
dp = kmem_intr_alloc(sizeof(*dp), KM_NOSLEEP);
mutex_enter(&arp_dad_lock);
if (arp_dad_find(ifa) != NULL) {
mutex_exit(&arp_dad_lock);
/* DAD already in progress */
if (dp != NULL)
kmem_intr_free(dp, sizeof(*dp));
return;
}
if (dp == NULL) {
mutex_exit(&arp_dad_lock);
log(LOG_ERR, "%s: memory allocation failed for %s(%s)\n",
__func__, IN_PRINT(ipbuf, &ia->ia_addr.sin_addr),
ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
return;
}
/*
* Send ARP packet for DAD, ip_dad_count times.
* Note that we must delay the first transmission.
*/
callout_init(&dp->dad_timer_ch, CALLOUT_MPSAFE);
dp->dad_ifa = ifa;
ifaref(ifa); /* just for safety */
dp->dad_count = ip_dad_count;
dp->dad_arp_announce = 0; /* Will be set when starting to announce */
dp->dad_arp_acount = dp->dad_arp_ocount = dp->dad_arp_tcount = 0;
TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
ARPLOG(LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
ARPLOGADDR(&ia->ia_addr.sin_addr));
arp_dad_starttimer(dp, cprng_fast32() % (PROBE_WAIT * hz));
mutex_exit(&arp_dad_lock);
}
/*
* terminate DAD unconditionally. used for address removals.
*/
static void
arp_dad_stop(struct ifaddr *ifa)
{
struct dadq *dp;
mutex_enter(&arp_dad_lock);
dp = arp_dad_find(ifa);
if (dp == NULL) {
mutex_exit(&arp_dad_lock);
/* DAD wasn't started yet */
return;
}
arp_dad_stoptimer(dp);
mutex_exit(&arp_dad_lock);
arp_dad_destroytimer(dp);
ifafree(ifa);
}
static void
arp_dad_timer(struct dadq *dp)
{
struct ifaddr *ifa;
struct in_ifaddr *ia;
char ipbuf[INET_ADDRSTRLEN];
bool need_free = false;
KERNEL_LOCK_UNLESS_NET_MPSAFE();
mutex_enter(&arp_dad_lock);
ifa = dp->dad_ifa;
if (ifa == NULL) {
/* dp is being destroyed by someone. Do nothing. */
goto done;
}
ia = (struct in_ifaddr *)ifa;
if (ia->ia4_flags & IN_IFF_DUPLICATED) {
log(LOG_ERR, "%s: called with duplicate address %s(%s)\n",
__func__, IN_PRINT(ipbuf, &ia->ia_addr.sin_addr),
ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
goto done;
}
if ((ia->ia4_flags & IN_IFF_TENTATIVE) == 0 && dp->dad_arp_acount == 0)
{
log(LOG_ERR, "%s: called with non-tentative address %s(%s)\n",
__func__, IN_PRINT(ipbuf, &ia->ia_addr.sin_addr),
ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
goto done;
}
/* timeouted with IFF_{RUNNING,UP} check */
if (dp->dad_arp_tcount > dad_maxtry) {
ARPLOG(LOG_INFO, "%s: could not run DAD, driver problem?\n",
if_name(ifa->ifa_ifp));
arp_dad_stoptimer(dp);
need_free = true;
goto done;
}
/* Need more checks? */
if (dp->dad_arp_ocount < dp->dad_count) {
int adelay;
/*
* We have more ARP to go. Send ARP packet for DAD.
*/
arp_dad_output(dp, ifa);
if (dp->dad_arp_ocount < dp->dad_count)
adelay = (PROBE_MIN * hz) +
(cprng_fast32() %
((PROBE_MAX * hz) - (PROBE_MIN * hz)));
else
adelay = ANNOUNCE_WAIT * hz;
arp_dad_starttimer(dp, adelay);
goto done;
} else if (dp->dad_arp_acount == 0) {
/*
* We are done with DAD.
* No duplicate address found.
*/
ia->ia4_flags &= ~IN_IFF_TENTATIVE;
rt_addrmsg(RTM_NEWADDR, ifa);
ARPLOG(LOG_DEBUG,
"%s: DAD complete for %s - no duplicates found\n",
if_name(ifa->ifa_ifp), ARPLOGADDR(&ia->ia_addr.sin_addr));
dp->dad_arp_announce = ANNOUNCE_NUM;
goto announce;
} else if (dp->dad_arp_acount < dp->dad_arp_announce) {
announce:
/*
* Announce the address.
*/
arpannounce1(ifa);
dp->dad_arp_acount++;
if (dp->dad_arp_acount < dp->dad_arp_announce) {
arp_dad_starttimer(dp, ANNOUNCE_INTERVAL * hz);
goto done;
}
ARPLOG(LOG_DEBUG,
"%s: ARP announcement complete for %s\n",
if_name(ifa->ifa_ifp), ARPLOGADDR(&ia->ia_addr.sin_addr));
}
arp_dad_stoptimer(dp);
need_free = true;
done:
mutex_exit(&arp_dad_lock);
if (need_free) {
arp_dad_destroytimer(dp);
KASSERT(ifa != NULL);
ifafree(ifa);
}
KERNEL_UNLOCK_UNLESS_NET_MPSAFE();
}
static void
arp_dad_duplicated(struct ifaddr *ifa, const struct sockaddr_dl *from)
{
struct in_ifaddr *ia = ifatoia(ifa);
struct ifnet *ifp = ifa->ifa_ifp;
char ipbuf[INET_ADDRSTRLEN], llabuf[LLA_ADDRSTRLEN];
const char *iastr, *llastr;
iastr = IN_PRINT(ipbuf, &ia->ia_addr.sin_addr);
if (__predict_false(from == NULL))
llastr = NULL;
else
llastr = lla_snprintf(llabuf, sizeof(llabuf),
CLLADDR(from), from->sdl_alen);
if (ia->ia4_flags & (IN_IFF_TENTATIVE|IN_IFF_DUPLICATED)) {
log(LOG_ERR,
"%s: DAD duplicate address %s from %s\n",
if_name(ifp), iastr, llastr);
} else if (ia->ia_dad_defended == 0 ||
ia->ia_dad_defended < time_uptime - DEFEND_INTERVAL) {
ia->ia_dad_defended = time_uptime;
arpannounce1(ifa);
log(LOG_ERR,
"%s: DAD defended address %s from %s\n",
if_name(ifp), iastr, llastr);
return;
} else {
/* If DAD is disabled, just report the duplicate. */
if (!ip_dad_enabled()) {
log(LOG_ERR,
"%s: DAD ignoring duplicate address %s from %s\n",
if_name(ifp), iastr, llastr);
return;
}
log(LOG_ERR,
"%s: DAD defence failed for %s from %s\n",
if_name(ifp), iastr, llastr);
}
arp_dad_stop(ifa);
ia->ia4_flags &= ~IN_IFF_TENTATIVE;
if ((ia->ia4_flags & IN_IFF_DUPLICATED) == 0) {
ia->ia4_flags |= IN_IFF_DUPLICATED;
/* Inform the routing socket of the duplicate address */
rt_addrmsg_src(RTM_NEWADDR, ifa, (const struct sockaddr *)from);
}
}
/*
* Called from 10 Mb/s Ethernet interrupt handlers
* when ether packet type ETHERTYPE_REVARP
* is received. Common length and type checks are done here,
* then the protocol-specific routine is called.
*/
void
revarpinput(struct mbuf *m)
{
struct arphdr *ar;
int arplen;
arplen = sizeof(struct arphdr);
if (m->m_len < arplen && (m = m_pullup(m, arplen)) == NULL)
return;
ar = mtod(m, struct arphdr *);
if (ntohs(ar->ar_hrd) == ARPHRD_IEEE1394) {
goto out;
}
arplen = sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln);
if (m->m_len < arplen && (m = m_pullup(m, arplen)) == NULL)
return;
ar = mtod(m, struct arphdr *);
switch (ntohs(ar->ar_pro)) {
case ETHERTYPE_IP:
case ETHERTYPE_IPTRAILERS:
in_revarpinput(m);
return;
default:
break;
}
out:
m_freem(m);
}
/*
* RARP for Internet protocols on 10 Mb/s Ethernet.
* Algorithm is that given in RFC 903.
* We are only using for bootstrap purposes to get an ip address for one of
* our interfaces. Thus we support no user-interface.
*
* Since the contents of the RARP reply are specific to the interface that
* sent the request, this code must ensure that they are properly associated.
*
* Note: also supports ARP via RARP packets, per the RFC.
*/
void
in_revarpinput(struct mbuf *m)
{
struct arphdr *ah;
void *tha;
int op;
struct ifnet *rcvif;
int s;
ah = mtod(m, struct arphdr *);
op = ntohs(ah->ar_op);
rcvif = m_get_rcvif(m, &s);
if (__predict_false(rcvif == NULL))
goto out;
if (rcvif->if_flags & IFF_NOARP)
goto out;
switch (rcvif->if_type) {
case IFT_IEEE1394:
/* ARP without target hardware address is not supported */
goto out;
default:
break;
}
switch (op) {
case ARPOP_REQUEST:
case ARPOP_REPLY: /* per RFC */
m_put_rcvif(rcvif, &s);
in_arpinput(m);
return;
case ARPOP_REVREPLY:
break;
case ARPOP_REVREQUEST: /* handled by rarpd(8) */
default:
goto out;
}
if (!revarp_in_progress)
goto out;
if (rcvif != myip_ifp) /* !same interface */
goto out;
if (myip_initialized)
goto wake;
tha = ar_tha(ah);
if (tha == NULL)
goto out;
if (ah->ar_pln != sizeof(struct in_addr))
goto out;
if (ah->ar_hln != rcvif->if_sadl->sdl_alen)
goto out;
if (memcmp(tha, CLLADDR(rcvif->if_sadl), rcvif->if_sadl->sdl_alen))
goto out;
memcpy(&srv_ip, ar_spa(ah), sizeof(srv_ip));
memcpy(&myip, ar_tpa(ah), sizeof(myip));
myip_initialized = 1;
wake: /* Do wakeup every time in case it was missed. */
wakeup((void *)&myip);
out:
m_put_rcvif(rcvif, &s);
m_freem(m);
}
/*
* Send a RARP request for the ip address of the specified interface.
* The request should be RFC 903-compliant.
*/
static void
revarprequest(struct ifnet *ifp)
{
struct sockaddr sa;
struct mbuf *m;
struct arphdr *ah;
void *tha;
if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
return;
MCLAIM(m, &arpdomain.dom_mowner);
m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) +
2*ifp->if_addrlen;
m->m_pkthdr.len = m->m_len;
m_align(m, m->m_len);
ah = mtod(m, struct arphdr *);
memset(ah, 0, m->m_len);
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_REVREQUEST);
memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln);
tha = ar_tha(ah);
if (tha == NULL) {
m_free(m);
return;
}
memcpy(tha, CLLADDR(ifp->if_sadl), ah->ar_hln);
sa.sa_family = AF_ARP;
sa.sa_len = 2;
m->m_flags |= M_BCAST;
if_output_lock(ifp, ifp, m, &sa, NULL);
}
/*
* RARP for the ip address of the specified interface, but also
* save the ip address of the server that sent the answer.
* Timeout if no response is received.
*/
int
revarpwhoarewe(struct ifnet *ifp, struct in_addr *serv_in,
struct in_addr *clnt_in)
{
int result, count = 20;
myip_initialized = 0;
myip_ifp = ifp;
revarp_in_progress = 1;
while (count--) {
revarprequest(ifp);
result = tsleep((void *)&myip, PSOCK, "revarp", hz/2);
if (result != EWOULDBLOCK)
break;
}
revarp_in_progress = 0;
if (!myip_initialized)
return ENETUNREACH;
memcpy(serv_in, &srv_ip, sizeof(*serv_in));
memcpy(clnt_in, &myip, sizeof(*clnt_in));
return 0;
}
void
arp_stat_add(int type, uint64_t count)
{
ARP_STATADD(type, count);
}
static int
sysctl_net_inet_arp_stats(SYSCTLFN_ARGS)
{
return NETSTAT_SYSCTL(arpstat_percpu, ARP_NSTATS);
}
static void
sysctl_net_inet_arp_setup(struct sysctllog **clog)
{
const struct sysctlnode *node;
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "inet", NULL,
NULL, 0, NULL, 0,
CTL_NET, PF_INET, CTL_EOL);
sysctl_createv(clog, 0, NULL, &node,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "arp",
SYSCTL_DESCR("Address Resolution Protocol"),
NULL, 0, NULL, 0,
CTL_NET, PF_INET, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "nd_delay",
SYSCTL_DESCR("First probe delay time"),
NULL, 0, &arp_nd_domain.nd_delay, 0,
CTL_NET, PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "nd_bmaxtries",
SYSCTL_DESCR("Number of broadcast discovery attempts"),
NULL, 0, &arp_nd_domain.nd_mmaxtries, 0,
CTL_NET, PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "nd_umaxtries",
SYSCTL_DESCR("Number of unicast discovery attempts"),
NULL, 0, &arp_nd_domain.nd_umaxtries, 0,
CTL_NET, PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "nd_reachable",
SYSCTL_DESCR("Reachable time"),
NULL, 0, &arp_reachable, 0,
CTL_NET, PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "nd_retrans",
SYSCTL_DESCR("Retransmission time"),
NULL, 0, &arp_retrans, 0,
CTL_NET, PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "nd_nud",
SYSCTL_DESCR("Perform neighbour unreachability detection"),
NULL, 0, &arp_perform_nud, 0,
CTL_NET, PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "nd_maxnudhint",
SYSCTL_DESCR("Maximum neighbor unreachable hint count"),
NULL, 0, &arp_nd_domain.nd_maxnudhint, 0,
CTL_NET, PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "maxqueuelen",
SYSCTL_DESCR("max packet queue len for a unresolved ARP"),
NULL, 1, &arp_nd_domain.nd_maxqueuelen, 0,
CTL_NET, PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_STRUCT, "stats",
SYSCTL_DESCR("ARP statistics"),
sysctl_net_inet_arp_stats, 0, NULL, 0,
CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "log_movements",
SYSCTL_DESCR("log ARP replies from MACs different than"
" the one in the cache"),
NULL, 0, &log_movements, 0,
CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "log_permanent_modify",
SYSCTL_DESCR("log ARP replies from MACs different than"
" the one in the permanent arp entry"),
NULL, 0, &log_permanent_modify, 0,
CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "log_wrong_iface",
SYSCTL_DESCR("log ARP packets arriving on the wrong"
" interface"),
NULL, 0, &log_wrong_iface, 0,
CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "debug",
SYSCTL_DESCR("Enable ARP DAD debug output"),
NULL, 0, &arp_debug, 0,
CTL_NET, PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
}
#endif /* INET */
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