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-rw-r--r--sys/net/if_ethersubr.c675
1 files changed, 675 insertions, 0 deletions
diff --git a/sys/net/if_ethersubr.c b/sys/net/if_ethersubr.c
new file mode 100644
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--- /dev/null
+++ b/sys/net/if_ethersubr.c
@@ -0,0 +1,675 @@
+/*
+ * Copyright (c) 1982, 1989, 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. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 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_ethersubr.c 8.1 (Berkeley) 6/10/93
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/mbuf.h>
+#include <sys/protosw.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <sys/errno.h>
+#include <sys/syslog.h>
+
+#include <machine/cpu.h>
+
+#include <net/if.h>
+#include <net/netisr.h>
+#include <net/route.h>
+#include <net/if_llc.h>
+#include <net/if_dl.h>
+#include <net/if_types.h>
+
+#ifdef INET
+#include <netinet/in.h>
+#include <netinet/in_var.h>
+#endif
+#include <netinet/if_ether.h>
+
+#ifdef NS
+#include <netns/ns.h>
+#include <netns/ns_if.h>
+#endif
+
+#ifdef ISO
+#include <netiso/argo_debug.h>
+#include <netiso/iso.h>
+#include <netiso/iso_var.h>
+#include <netiso/iso_snpac.h>
+#endif
+
+#ifdef LLC
+#include <netccitt/dll.h>
+#include <netccitt/llc_var.h>
+#endif
+
+#if defined(LLC) && defined(CCITT)
+extern struct ifqueue pkintrq;
+#endif
+
+u_char etherbroadcastaddr[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
+extern struct ifnet loif;
+#define senderr(e) { error = (e); goto bad;}
+
+/*
+ * Ethernet output routine.
+ * Encapsulate a packet of type family for the local net.
+ * Use trailer local net encapsulation if enough data in first
+ * packet leaves a multiple of 512 bytes of data in remainder.
+ * Assumes that ifp is actually pointer to arpcom structure.
+ */
+int
+ether_output(ifp, m0, dst, rt0)
+ register struct ifnet *ifp;
+ struct mbuf *m0;
+ struct sockaddr *dst;
+ struct rtentry *rt0;
+{
+ short type;
+ int s, error = 0;
+ u_char edst[6];
+ register struct mbuf *m = m0;
+ register struct rtentry *rt;
+ struct mbuf *mcopy = (struct mbuf *)0;
+ register struct ether_header *eh;
+ int off, len = m->m_pkthdr.len;
+ struct arpcom *ac = (struct arpcom *)ifp;
+
+ if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
+ senderr(ENETDOWN);
+ ifp->if_lastchange = time;
+ if (rt = rt0) {
+ if ((rt->rt_flags & RTF_UP) == 0) {
+ if (rt0 = rt = rtalloc1(dst, 1))
+ rt->rt_refcnt--;
+ else
+ senderr(EHOSTUNREACH);
+ }
+ if (rt->rt_flags & RTF_GATEWAY) {
+ if (rt->rt_gwroute == 0)
+ goto lookup;
+ if (((rt = rt->rt_gwroute)->rt_flags & RTF_UP) == 0) {
+ rtfree(rt); rt = rt0;
+ lookup: rt->rt_gwroute = rtalloc1(rt->rt_gateway, 1);
+ if ((rt = rt->rt_gwroute) == 0)
+ senderr(EHOSTUNREACH);
+ }
+ }
+ if (rt->rt_flags & RTF_REJECT)
+ if (rt->rt_rmx.rmx_expire == 0 ||
+ time.tv_sec < rt->rt_rmx.rmx_expire)
+ senderr(rt == rt0 ? EHOSTDOWN : EHOSTUNREACH);
+ }
+ switch (dst->sa_family) {
+
+#ifdef INET
+ case AF_INET:
+ if (!arpresolve(ac, rt, m, dst, edst))
+ return (0); /* if not yet resolved */
+ /* If broadcasting on a simplex interface, loopback a copy */
+ if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
+ mcopy = m_copy(m, 0, (int)M_COPYALL);
+ off = m->m_pkthdr.len - m->m_len;
+ type = ETHERTYPE_IP;
+ break;
+#endif
+#ifdef NS
+ case AF_NS:
+ type = ETHERTYPE_NS;
+ bcopy((caddr_t)&(((struct sockaddr_ns *)dst)->sns_addr.x_host),
+ (caddr_t)edst, sizeof (edst));
+ if (!bcmp((caddr_t)edst, (caddr_t)&ns_thishost, sizeof(edst)))
+ return (looutput(ifp, m, dst, rt));
+ /* If broadcasting on a simplex interface, loopback a copy */
+ if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
+ mcopy = m_copy(m, 0, (int)M_COPYALL);
+ break;
+#endif
+#ifdef ISO
+ case AF_ISO: {
+ int snpalen;
+ struct llc *l;
+ register struct sockaddr_dl *sdl;
+
+ if (rt && (sdl = (struct sockaddr_dl *)rt->rt_gateway) &&
+ sdl->sdl_family == AF_LINK && sdl->sdl_alen > 0) {
+ bcopy(LLADDR(sdl), (caddr_t)edst, sizeof(edst));
+ } else if (error =
+ iso_snparesolve(ifp, (struct sockaddr_iso *)dst,
+ (char *)edst, &snpalen))
+ goto bad; /* Not Resolved */
+ /* If broadcasting on a simplex interface, loopback a copy */
+ if (*edst & 1)
+ m->m_flags |= (M_BCAST|M_MCAST);
+ if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX) &&
+ (mcopy = m_copy(m, 0, (int)M_COPYALL))) {
+ M_PREPEND(mcopy, sizeof (*eh), M_DONTWAIT);
+ if (mcopy) {
+ eh = mtod(mcopy, struct ether_header *);
+ bcopy((caddr_t)edst,
+ (caddr_t)eh->ether_dhost, sizeof (edst));
+ bcopy((caddr_t)ac->ac_enaddr,
+ (caddr_t)eh->ether_shost, sizeof (edst));
+ }
+ }
+ M_PREPEND(m, 3, M_DONTWAIT);
+ if (m == NULL)
+ return (0);
+ type = m->m_pkthdr.len;
+ l = mtod(m, struct llc *);
+ l->llc_dsap = l->llc_ssap = LLC_ISO_LSAP;
+ l->llc_control = LLC_UI;
+ len += 3;
+ IFDEBUG(D_ETHER)
+ int i;
+ printf("unoutput: sending pkt to: ");
+ for (i=0; i<6; i++)
+ printf("%x ", edst[i] & 0xff);
+ printf("\n");
+ ENDDEBUG
+ } break;
+#endif /* ISO */
+#ifdef LLC
+/* case AF_NSAP: */
+ case AF_CCITT: {
+ register struct sockaddr_dl *sdl =
+ (struct sockaddr_dl *) rt -> rt_gateway;
+
+ if (sdl && sdl->sdl_family == AF_LINK
+ && sdl->sdl_alen > 0) {
+ bcopy(LLADDR(sdl), (char *)edst,
+ sizeof(edst));
+ } else goto bad; /* Not a link interface ? Funny ... */
+ if ((ifp->if_flags & IFF_SIMPLEX) && (*edst & 1) &&
+ (mcopy = m_copy(m, 0, (int)M_COPYALL))) {
+ M_PREPEND(mcopy, sizeof (*eh), M_DONTWAIT);
+ if (mcopy) {
+ eh = mtod(mcopy, struct ether_header *);
+ bcopy((caddr_t)edst,
+ (caddr_t)eh->ether_dhost, sizeof (edst));
+ bcopy((caddr_t)ac->ac_enaddr,
+ (caddr_t)eh->ether_shost, sizeof (edst));
+ }
+ }
+ type = m->m_pkthdr.len;
+#ifdef LLC_DEBUG
+ {
+ int i;
+ register struct llc *l = mtod(m, struct llc *);
+
+ printf("ether_output: sending LLC2 pkt to: ");
+ for (i=0; i<6; i++)
+ printf("%x ", edst[i] & 0xff);
+ printf(" len 0x%x dsap 0x%x ssap 0x%x control 0x%x\n",
+ type & 0xff, l->llc_dsap & 0xff, l->llc_ssap &0xff,
+ l->llc_control & 0xff);
+
+ }
+#endif /* LLC_DEBUG */
+ } break;
+#endif /* LLC */
+
+ case AF_UNSPEC:
+ eh = (struct ether_header *)dst->sa_data;
+ bcopy((caddr_t)eh->ether_dhost, (caddr_t)edst, sizeof (edst));
+ type = eh->ether_type;
+ break;
+
+ default:
+ printf("%s%d: can't handle af%d\n", ifp->if_name, ifp->if_unit,
+ dst->sa_family);
+ senderr(EAFNOSUPPORT);
+ }
+
+
+ if (mcopy)
+ (void) looutput(ifp, mcopy, dst, rt);
+ /*
+ * Add local net header. If no space in first mbuf,
+ * allocate another.
+ */
+ M_PREPEND(m, sizeof (struct ether_header), M_DONTWAIT);
+ if (m == 0)
+ senderr(ENOBUFS);
+ eh = mtod(m, struct ether_header *);
+ type = htons((u_short)type);
+ bcopy((caddr_t)&type,(caddr_t)&eh->ether_type,
+ sizeof(eh->ether_type));
+ bcopy((caddr_t)edst, (caddr_t)eh->ether_dhost, sizeof (edst));
+ bcopy((caddr_t)ac->ac_enaddr, (caddr_t)eh->ether_shost,
+ sizeof(eh->ether_shost));
+ s = splimp();
+ /*
+ * Queue message on interface, and start output if interface
+ * not yet active.
+ */
+ if (IF_QFULL(&ifp->if_snd)) {
+ IF_DROP(&ifp->if_snd);
+ splx(s);
+ senderr(ENOBUFS);
+ }
+ IF_ENQUEUE(&ifp->if_snd, m);
+ if ((ifp->if_flags & IFF_OACTIVE) == 0)
+ (*ifp->if_start)(ifp);
+ splx(s);
+ ifp->if_obytes += len + sizeof (struct ether_header);
+ if (m->m_flags & M_MCAST)
+ ifp->if_omcasts++;
+ return (error);
+
+bad:
+ if (m)
+ m_freem(m);
+ return (error);
+}
+
+/*
+ * Process a received Ethernet packet;
+ * the packet is in the mbuf chain m without
+ * the ether header, which is provided separately.
+ */
+void
+ether_input(ifp, eh, m)
+ struct ifnet *ifp;
+ register struct ether_header *eh;
+ struct mbuf *m;
+{
+ register struct ifqueue *inq;
+ register struct llc *l;
+ struct arpcom *ac = (struct arpcom *)ifp;
+ int s;
+
+ if ((ifp->if_flags & IFF_UP) == 0) {
+ m_freem(m);
+ return;
+ }
+ ifp->if_lastchange = time;
+ ifp->if_ibytes += m->m_pkthdr.len + sizeof (*eh);
+ if (bcmp((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost,
+ sizeof(etherbroadcastaddr)) == 0)
+ m->m_flags |= M_BCAST;
+ else if (eh->ether_dhost[0] & 1)
+ m->m_flags |= M_MCAST;
+ if (m->m_flags & (M_BCAST|M_MCAST))
+ ifp->if_imcasts++;
+
+ switch (eh->ether_type) {
+#ifdef INET
+ case ETHERTYPE_IP:
+ schednetisr(NETISR_IP);
+ inq = &ipintrq;
+ break;
+
+ case ETHERTYPE_ARP:
+ schednetisr(NETISR_ARP);
+ inq = &arpintrq;
+ break;
+#endif
+#ifdef NS
+ case ETHERTYPE_NS:
+ schednetisr(NETISR_NS);
+ inq = &nsintrq;
+ break;
+
+#endif
+ default:
+#if defined (ISO) || defined (LLC)
+ if (eh->ether_type > ETHERMTU)
+ goto dropanyway;
+ l = mtod(m, struct llc *);
+ switch (l->llc_dsap) {
+#ifdef ISO
+ case LLC_ISO_LSAP:
+ switch (l->llc_control) {
+ case LLC_UI:
+ /* LLC_UI_P forbidden in class 1 service */
+ if ((l->llc_dsap == LLC_ISO_LSAP) &&
+ (l->llc_ssap == LLC_ISO_LSAP)) {
+ /* LSAP for ISO */
+ if (m->m_pkthdr.len > eh->ether_type)
+ m_adj(m, eh->ether_type - m->m_pkthdr.len);
+ m->m_data += 3; /* XXX */
+ m->m_len -= 3; /* XXX */
+ m->m_pkthdr.len -= 3; /* XXX */
+ M_PREPEND(m, sizeof *eh, M_DONTWAIT);
+ if (m == 0)
+ return;
+ *mtod(m, struct ether_header *) = *eh;
+ IFDEBUG(D_ETHER)
+ printf("clnp packet");
+ ENDDEBUG
+ schednetisr(NETISR_ISO);
+ inq = &clnlintrq;
+ break;
+ }
+ goto dropanyway;
+
+ case LLC_XID:
+ case LLC_XID_P:
+ if(m->m_len < 6)
+ goto dropanyway;
+ l->llc_window = 0;
+ l->llc_fid = 9;
+ l->llc_class = 1;
+ l->llc_dsap = l->llc_ssap = 0;
+ /* Fall through to */
+ case LLC_TEST:
+ case LLC_TEST_P:
+ {
+ struct sockaddr sa;
+ register struct ether_header *eh2;
+ int i;
+ u_char c = l->llc_dsap;
+
+ l->llc_dsap = l->llc_ssap;
+ l->llc_ssap = c;
+ if (m->m_flags & (M_BCAST | M_MCAST))
+ bcopy((caddr_t)ac->ac_enaddr,
+ (caddr_t)eh->ether_dhost, 6);
+ sa.sa_family = AF_UNSPEC;
+ sa.sa_len = sizeof(sa);
+ eh2 = (struct ether_header *)sa.sa_data;
+ for (i = 0; i < 6; i++) {
+ eh2->ether_shost[i] = c = eh->ether_dhost[i];
+ eh2->ether_dhost[i] =
+ eh->ether_dhost[i] = eh->ether_shost[i];
+ eh->ether_shost[i] = c;
+ }
+ ifp->if_output(ifp, m, &sa, NULL);
+ return;
+ }
+ default:
+ m_freem(m);
+ return;
+ }
+ break;
+#endif /* ISO */
+#ifdef LLC
+ case LLC_X25_LSAP:
+ {
+ if (m->m_pkthdr.len > eh->ether_type)
+ m_adj(m, eh->ether_type - m->m_pkthdr.len);
+ M_PREPEND(m, sizeof(struct sdl_hdr) , M_DONTWAIT);
+ if (m == 0)
+ return;
+ if ( !sdl_sethdrif(ifp, eh->ether_shost, LLC_X25_LSAP,
+ eh->ether_dhost, LLC_X25_LSAP, 6,
+ mtod(m, struct sdl_hdr *)))
+ panic("ETHER cons addr failure");
+ mtod(m, struct sdl_hdr *)->sdlhdr_len = eh->ether_type;
+#ifdef LLC_DEBUG
+ printf("llc packet\n");
+#endif /* LLC_DEBUG */
+ schednetisr(NETISR_CCITT);
+ inq = &llcintrq;
+ break;
+ }
+#endif /* LLC */
+ dropanyway:
+ default:
+ m_freem(m);
+ return;
+ }
+#else /* ISO || LLC */
+ m_freem(m);
+ return;
+#endif /* ISO || LLC */
+ }
+
+ s = splimp();
+ if (IF_QFULL(inq)) {
+ IF_DROP(inq);
+ m_freem(m);
+ } else
+ IF_ENQUEUE(inq, m);
+ splx(s);
+}
+
+/*
+ * Convert Ethernet address to printable (loggable) representation.
+ */
+static char digits[] = "0123456789abcdef";
+char *
+ether_sprintf(ap)
+ register u_char *ap;
+{
+ register i;
+ static char etherbuf[18];
+ register char *cp = etherbuf;
+
+ for (i = 0; i < 6; i++) {
+ *cp++ = digits[*ap >> 4];
+ *cp++ = digits[*ap++ & 0xf];
+ *cp++ = ':';
+ }
+ *--cp = 0;
+ return (etherbuf);
+}
+
+/*
+ * Perform common duties while attaching to interface list
+ */
+void
+ether_ifattach(ifp)
+ register struct ifnet *ifp;
+{
+ register struct ifaddr *ifa;
+ register struct sockaddr_dl *sdl;
+
+ ifp->if_type = IFT_ETHER;
+ ifp->if_addrlen = 6;
+ ifp->if_hdrlen = 14;
+ ifp->if_mtu = ETHERMTU;
+ for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
+ if ((sdl = (struct sockaddr_dl *)ifa->ifa_addr) &&
+ sdl->sdl_family == AF_LINK) {
+ sdl->sdl_type = IFT_ETHER;
+ sdl->sdl_alen = ifp->if_addrlen;
+ bcopy((caddr_t)((struct arpcom *)ifp)->ac_enaddr,
+ LLADDR(sdl), ifp->if_addrlen);
+ break;
+ }
+}
+
+u_char ether_ipmulticast_min[6] = { 0x01, 0x00, 0x5e, 0x00, 0x00, 0x00 };
+u_char ether_ipmulticast_max[6] = { 0x01, 0x00, 0x5e, 0x7f, 0xff, 0xff };
+/*
+ * Add an Ethernet multicast address or range of addresses to the list for a
+ * given interface.
+ */
+int
+ether_addmulti(ifr, ac)
+ struct ifreq *ifr;
+ register struct arpcom *ac;
+{
+ register struct ether_multi *enm;
+ struct sockaddr_in *sin;
+ u_char addrlo[6];
+ u_char addrhi[6];
+ int s = splimp();
+
+ switch (ifr->ifr_addr.sa_family) {
+
+ case AF_UNSPEC:
+ bcopy(ifr->ifr_addr.sa_data, addrlo, 6);
+ bcopy(addrlo, addrhi, 6);
+ break;
+
+#ifdef INET
+ case AF_INET:
+ sin = (struct sockaddr_in *)&(ifr->ifr_addr);
+ if (sin->sin_addr.s_addr == INADDR_ANY) {
+ /*
+ * An IP address of INADDR_ANY means listen to all
+ * of the Ethernet multicast addresses used for IP.
+ * (This is for the sake of IP multicast routers.)
+ */
+ bcopy(ether_ipmulticast_min, addrlo, 6);
+ bcopy(ether_ipmulticast_max, addrhi, 6);
+ }
+ else {
+ ETHER_MAP_IP_MULTICAST(&sin->sin_addr, addrlo);
+ bcopy(addrlo, addrhi, 6);
+ }
+ break;
+#endif
+
+ default:
+ splx(s);
+ return (EAFNOSUPPORT);
+ }
+
+ /*
+ * Verify that we have valid Ethernet multicast addresses.
+ */
+ if ((addrlo[0] & 0x01) != 1 || (addrhi[0] & 0x01) != 1) {
+ splx(s);
+ return (EINVAL);
+ }
+ /*
+ * See if the address range is already in the list.
+ */
+ ETHER_LOOKUP_MULTI(addrlo, addrhi, ac, enm);
+ if (enm != NULL) {
+ /*
+ * Found it; just increment the reference count.
+ */
+ ++enm->enm_refcount;
+ splx(s);
+ return (0);
+ }
+ /*
+ * New address or range; malloc a new multicast record
+ * and link it into the interface's multicast list.
+ */
+ enm = (struct ether_multi *)malloc(sizeof(*enm), M_IFMADDR, M_NOWAIT);
+ if (enm == NULL) {
+ splx(s);
+ return (ENOBUFS);
+ }
+ bcopy(addrlo, enm->enm_addrlo, 6);
+ bcopy(addrhi, enm->enm_addrhi, 6);
+ enm->enm_ac = ac;
+ enm->enm_refcount = 1;
+ enm->enm_next = ac->ac_multiaddrs;
+ ac->ac_multiaddrs = enm;
+ ac->ac_multicnt++;
+ splx(s);
+ /*
+ * Return ENETRESET to inform the driver that the list has changed
+ * and its reception filter should be adjusted accordingly.
+ */
+ return (ENETRESET);
+}
+
+/*
+ * Delete a multicast address record.
+ */
+int
+ether_delmulti(ifr, ac)
+ struct ifreq *ifr;
+ register struct arpcom *ac;
+{
+ register struct ether_multi *enm;
+ register struct ether_multi **p;
+ struct sockaddr_in *sin;
+ u_char addrlo[6];
+ u_char addrhi[6];
+ int s = splimp();
+
+ switch (ifr->ifr_addr.sa_family) {
+
+ case AF_UNSPEC:
+ bcopy(ifr->ifr_addr.sa_data, addrlo, 6);
+ bcopy(addrlo, addrhi, 6);
+ break;
+
+#ifdef INET
+ case AF_INET:
+ sin = (struct sockaddr_in *)&(ifr->ifr_addr);
+ if (sin->sin_addr.s_addr == INADDR_ANY) {
+ /*
+ * An IP address of INADDR_ANY means stop listening
+ * to the range of Ethernet multicast addresses used
+ * for IP.
+ */
+ bcopy(ether_ipmulticast_min, addrlo, 6);
+ bcopy(ether_ipmulticast_max, addrhi, 6);
+ }
+ else {
+ ETHER_MAP_IP_MULTICAST(&sin->sin_addr, addrlo);
+ bcopy(addrlo, addrhi, 6);
+ }
+ break;
+#endif
+
+ default:
+ splx(s);
+ return (EAFNOSUPPORT);
+ }
+
+ /*
+ * Look up the address in our list.
+ */
+ ETHER_LOOKUP_MULTI(addrlo, addrhi, ac, enm);
+ if (enm == NULL) {
+ splx(s);
+ return (ENXIO);
+ }
+ if (--enm->enm_refcount != 0) {
+ /*
+ * Still some claims to this record.
+ */
+ splx(s);
+ return (0);
+ }
+ /*
+ * No remaining claims to this record; unlink and free it.
+ */
+ for (p = &enm->enm_ac->ac_multiaddrs;
+ *p != enm;
+ p = &(*p)->enm_next)
+ continue;
+ *p = (*p)->enm_next;
+ free(enm, M_IFMADDR);
+ ac->ac_multicnt--;
+ splx(s);
+ /*
+ * Return ENETRESET to inform the driver that the list has changed
+ * and its reception filter should be adjusted accordingly.
+ */
+ return (ENETRESET);
+}
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