text: /*-
   * Copyright (c) 1982, 1986, 1991, 1993
   *	The Regents of the University of California.  All rights reserved.
   * Copyright (C) 2001 WIDE Project.  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.
   *
   *	@(#)in.c	8.4 (Berkeley) 1/9/95
   */
  
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD: release/9.1.0/sys/netinet/in.c 233200 2012-03-19 20:49:16Z jhb $");
  
  #include "opt_mpath.h"
  
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/sockio.h>
  #include <sys/malloc.h>
  #include <sys/priv.h>
  #include <sys/socket.h>
  #include <sys/jail.h>
  #include <sys/kernel.h>
  #include <sys/proc.h>
  #include <sys/sysctl.h>
  #include <sys/syslog.h>
  
  #include <net/if.h>
  #include <net/if_var.h>
  #include <net/if_arp.h>
  #include <net/if_dl.h>
  #include <net/if_llatbl.h>
  #include <net/if_types.h>
  #include <net/route.h>
  #include <net/vnet.h>
  
  #include <netinet/in.h>
  #include <netinet/in_var.h>
  #include <netinet/in_pcb.h>
  #include <netinet/ip_var.h>
  #include <netinet/igmp_var.h>
  #include <netinet/udp.h>
  #include <netinet/udp_var.h>
  
  static int in_mask2len(struct in_addr *);
  static void in_len2mask(struct in_addr *, int);
  static int in_lifaddr_ioctl(struct socket *, u_long, caddr_t,
  	struct ifnet *, struct thread *);
  
  static int	in_addprefix(struct in_ifaddr *, int);
  static int	in_scrubprefix(struct in_ifaddr *, u_int);
  static void	in_socktrim(struct sockaddr_in *);
  static int	in_ifinit(struct ifnet *,
  	    struct in_ifaddr *, struct sockaddr_in *, int);
  static void	in_purgemaddrs(struct ifnet *);
  
  static VNET_DEFINE(int, sameprefixcarponly);
  #define	V_sameprefixcarponly		VNET(sameprefixcarponly)
  SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, same_prefix_carp_only, CTLFLAG_RW,
  	&VNET_NAME(sameprefixcarponly), 0,
  	"Refuse to create same prefixes on different interfaces");
  
  VNET_DECLARE(struct inpcbinfo, ripcbinfo);
  #define	V_ripcbinfo			VNET(ripcbinfo)
  
  VNET_DECLARE(struct arpstat, arpstat);  /* ARP statistics, see if_arp.h */
  #define	V_arpstat		VNET(arpstat)
  
  /*
   * Return 1 if an internet address is for a ``local'' host
   * (one to which we have a connection).
   */
  int
  in_localaddr(struct in_addr in)
  {
  	register u_long i = ntohl(in.s_addr);
  	register struct in_ifaddr *ia;
  
  	IN_IFADDR_RLOCK();
  	TAILQ_FOREACH(ia, &V_in_ifaddrhead, ia_link) {
  		if ((i & ia->ia_subnetmask) == ia->ia_subnet) {
  			IN_IFADDR_RUNLOCK();
  			return (1);
  		}
  	}
  	IN_IFADDR_RUNLOCK();
  	return (0);
  }
  
  /*
   * Return 1 if an internet address is for the local host and configured
   * on one of its interfaces.
   */
  int
  in_localip(struct in_addr in)
  {
  	struct in_ifaddr *ia;
  
  	IN_IFADDR_RLOCK();
  	LIST_FOREACH(ia, INADDR_HASH(in.s_addr), ia_hash) {
  		if (IA_SIN(ia)->sin_addr.s_addr == in.s_addr) {
  			IN_IFADDR_RUNLOCK();
  			return (1);
  		}
  	}
  	IN_IFADDR_RUNLOCK();
  	return (0);
  }
  
  /*
   * Determine whether an IP address is in a reserved set of addresses
   * that may not be forwarded, or whether datagrams to that destination
   * may be forwarded.
   */
  int
  in_canforward(struct in_addr in)
  {
  	register u_long i = ntohl(in.s_addr);
  	register u_long net;
  
  	if (IN_EXPERIMENTAL(i) || IN_MULTICAST(i) || IN_LINKLOCAL(i))
  		return (0);
  	if (IN_CLASSA(i)) {
  		net = i & IN_CLASSA_NET;
  		if (net == 0 || net == (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))
  			return (0);
  	}
  	return (1);
  }
  
  /*
   * Trim a mask in a sockaddr
   */
  static void
  in_socktrim(struct sockaddr_in *ap)
  {
      register char *cplim = (char *) &ap->sin_addr;
      register char *cp = (char *) (&ap->sin_addr + 1);
  
      ap->sin_len = 0;
      while (--cp >= cplim)
  	if (*cp) {
  	    (ap)->sin_len = cp - (char *) (ap) + 1;
  	    break;
  	}
  }
  
  static int
  in_mask2len(mask)
  	struct in_addr *mask;
  {
  	int x, y;
  	u_char *p;
  
  	p = (u_char *)mask;
  	for (x = 0; x < sizeof(*mask); x++) {
  		if (p[x] != 0xff)
  			break;
  	}
  	y = 0;
  	if (x < sizeof(*mask)) {
  		for (y = 0; y < 8; y++) {
  			if ((p[x] & (0x80 >> y)) == 0)
  				break;
  		}
  	}
  	return (x * 8 + y);
  }
  
  static void
  in_len2mask(struct in_addr *mask, int len)
  {
  	int i;
  	u_char *p;
  
  	p = (u_char *)mask;
  	bzero(mask, sizeof(*mask));
  	for (i = 0; i < len / 8; i++)
  		p[i] = 0xff;
  	if (len % 8)
  		p[i] = (0xff00 >> (len % 8)) & 0xff;
  }
  
  /*
   * Generic internet control operations (ioctl's).
   *
   * ifp is NULL if not an interface-specific ioctl.
   */
  /* ARGSUSED */
  int
  in_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp,
      struct thread *td)
  {
  	register struct ifreq *ifr = (struct ifreq *)data;
  	register struct in_ifaddr *ia, *iap;
  	register struct ifaddr *ifa;
  	struct in_addr allhosts_addr;
  	struct in_addr dst;
  	struct in_ifinfo *ii;
  	struct in_aliasreq *ifra = (struct in_aliasreq *)data;
  	struct sockaddr_in oldaddr;
  	int error, hostIsNew, iaIsNew, maskIsNew;
  	int iaIsFirst;
  
  	ia = NULL;
  	iaIsFirst = 0;
  	iaIsNew = 0;
  	allhosts_addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
  
  	/*
  	 * Filter out ioctls we implement directly; forward the rest on to
  	 * in_lifaddr_ioctl() and ifp->if_ioctl().
  	 */
  	switch (cmd) {
  	case SIOCAIFADDR:
  	case SIOCDIFADDR:
  	case SIOCGIFADDR:
  	case SIOCGIFBRDADDR:
  	case SIOCGIFDSTADDR:
  	case SIOCGIFNETMASK:
  	case SIOCSIFADDR:
  	case SIOCSIFBRDADDR:
  	case SIOCSIFDSTADDR:
  	case SIOCSIFNETMASK:
  		break;
  
  	case SIOCALIFADDR:
  		if (td != NULL) {
  			error = priv_check(td, PRIV_NET_ADDIFADDR);
  			if (error)
  				return (error);
  		}
  		if (ifp == NULL)
  			return (EINVAL);
  		return in_lifaddr_ioctl(so, cmd, data, ifp, td);
  
  	case SIOCDLIFADDR:
  		if (td != NULL) {
  			error = priv_check(td, PRIV_NET_DELIFADDR);
  			if (error)
  				return (error);
  		}
  		if (ifp == NULL)
  			return (EINVAL);
  		return in_lifaddr_ioctl(so, cmd, data, ifp, td);
  
  	case SIOCGLIFADDR:
  		if (ifp == NULL)
  			return (EINVAL);
  		return in_lifaddr_ioctl(so, cmd, data, ifp, td);
  
  	default:
  		if (ifp == NULL || ifp->if_ioctl == NULL)
  			return (EOPNOTSUPP);
  		return ((*ifp->if_ioctl)(ifp, cmd, data));
  	}
  
  	if (ifp == NULL)
  		return (EADDRNOTAVAIL);
  
  	/*
  	 * Security checks before we get involved in any work.
  	 */
  	switch (cmd) {
  	case SIOCAIFADDR:
  	case SIOCSIFADDR:
  	case SIOCSIFBRDADDR:
  	case SIOCSIFNETMASK:
  	case SIOCSIFDSTADDR:
  		if (td != NULL) {
  			error = priv_check(td, PRIV_NET_ADDIFADDR);
  			if (error)
  				return (error);
  		}
  		break;
  
  	case SIOCDIFADDR:
  		if (td != NULL) {
  			error = priv_check(td, PRIV_NET_DELIFADDR);
  			if (error)
  				return (error);
  		}
  		break;
  	}
  
  	/*
  	 * Find address for this interface, if it exists.
  	 *
  	 * If an alias address was specified, find that one instead of the
  	 * first one on the interface, if possible.
  	 */
  	dst = ((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr;
  	IN_IFADDR_RLOCK();
  	LIST_FOREACH(iap, INADDR_HASH(dst.s_addr), ia_hash) {
  		if (iap->ia_ifp == ifp &&
  		    iap->ia_addr.sin_addr.s_addr == dst.s_addr) {
  			if (td == NULL || prison_check_ip4(td->td_ucred,
  			    &dst) == 0)
  				ia = iap;
  			break;
  		}
  	}
  	if (ia != NULL)
  		ifa_ref(&ia->ia_ifa);
  	IN_IFADDR_RUNLOCK();
  	if (ia == NULL) {
  		IF_ADDR_RLOCK(ifp);
  		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
  			iap = ifatoia(ifa);
  			if (iap->ia_addr.sin_family == AF_INET) {
  				if (td != NULL &&
  				    prison_check_ip4(td->td_ucred,
  				    &iap->ia_addr.sin_addr) != 0)
  					continue;
  				ia = iap;
  				break;
  			}
  		}
  		if (ia != NULL)
  			ifa_ref(&ia->ia_ifa);
  		IF_ADDR_RUNLOCK(ifp);
  	}
  	if (ia == NULL)
  		iaIsFirst = 1;
  
  	error = 0;
  	switch (cmd) {
  	case SIOCAIFADDR:
  	case SIOCDIFADDR:
  		if (ifra->ifra_addr.sin_family == AF_INET) {
  			struct in_ifaddr *oia;
  
  			IN_IFADDR_RLOCK();
  			for (oia = ia; ia; ia = TAILQ_NEXT(ia, ia_link)) {
  				if (ia->ia_ifp == ifp  &&
  				    ia->ia_addr.sin_addr.s_addr ==
  				    ifra->ifra_addr.sin_addr.s_addr)
  					break;
  			}
  			if (ia != NULL && ia != oia)
  				ifa_ref(&ia->ia_ifa);
  			if (oia != NULL && ia != oia)
  				ifa_free(&oia->ia_ifa);
  			IN_IFADDR_RUNLOCK();
  			if ((ifp->if_flags & IFF_POINTOPOINT)
  			    && (cmd == SIOCAIFADDR)
  			    && (ifra->ifra_dstaddr.sin_addr.s_addr
  				== INADDR_ANY)) {
  				error = EDESTADDRREQ;
  				goto out;
  			}
  		}
  		if (cmd == SIOCDIFADDR && ia == NULL) {
  			error = EADDRNOTAVAIL;
  			goto out;
  		}
  		/* FALLTHROUGH */
  	case SIOCSIFADDR:
  	case SIOCSIFNETMASK:
  	case SIOCSIFDSTADDR:
  		if (ia == NULL) {
  			ia = (struct in_ifaddr *)
  				malloc(sizeof *ia, M_IFADDR, M_NOWAIT |
  				    M_ZERO);
  			if (ia == NULL) {
  				error = ENOBUFS;
  				goto out;
  			}
  
  			ifa = &ia->ia_ifa;
  			ifa_init(ifa);
  			ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr;
  			ifa->ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
  			ifa->ifa_netmask = (struct sockaddr *)&ia->ia_sockmask;
  
  			ia->ia_sockmask.sin_len = 8;
  			ia->ia_sockmask.sin_family = AF_INET;
  			if (ifp->if_flags & IFF_BROADCAST) {
  				ia->ia_broadaddr.sin_len = sizeof(ia->ia_addr);
  				ia->ia_broadaddr.sin_family = AF_INET;
  			}
  			ia->ia_ifp = ifp;
  
  			ifa_ref(ifa);			/* if_addrhead */
  			IF_ADDR_WLOCK(ifp);
  			TAILQ_INSERT_TAIL(&ifp->if_addrhead, ifa, ifa_link);
  			IF_ADDR_WUNLOCK(ifp);
  			ifa_ref(ifa);			/* in_ifaddrhead */
  			IN_IFADDR_WLOCK();
  			TAILQ_INSERT_TAIL(&V_in_ifaddrhead, ia, ia_link);
  			IN_IFADDR_WUNLOCK();
  			iaIsNew = 1;
  		}
  		break;
  
  	case SIOCSIFBRDADDR:
  	case SIOCGIFADDR:
  	case SIOCGIFNETMASK:
  	case SIOCGIFDSTADDR:
  	case SIOCGIFBRDADDR:
  		if (ia == NULL) {
  			error = EADDRNOTAVAIL;
  			goto out;
  		}
  		break;
  	}
  
  	/*
  	 * Most paths in this switch return directly or via out.  Only paths
  	 * that remove the address break in order to hit common removal code.
  	 */
  	switch (cmd) {
  	case SIOCGIFADDR:
  		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_addr;
  		goto out;
  
  	case SIOCGIFBRDADDR:
  		if ((ifp->if_flags & IFF_BROADCAST) == 0) {
  			error = EINVAL;
  			goto out;
  		}
  		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_broadaddr;
  		goto out;
  
  	case SIOCGIFDSTADDR:
  		if ((ifp->if_flags & IFF_POINTOPOINT) == 0) {
  			error = EINVAL;
  			goto out;
  		}
  		*((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_dstaddr;
  		goto out;
  
  	case SIOCGIFNETMASK:
  		*((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_sockmask;
  		goto out;
  
  	case SIOCSIFDSTADDR:
  		if ((ifp->if_flags & IFF_POINTOPOINT) == 0) {
  			error = EINVAL;
  			goto out;
  		}
  		oldaddr = ia->ia_dstaddr;
  		ia->ia_dstaddr = *(struct sockaddr_in *)&ifr->ifr_dstaddr;
  		if (ifp->if_ioctl != NULL) {
  			error = (*ifp->if_ioctl)(ifp, SIOCSIFDSTADDR,
  			    (caddr_t)ia);
  			if (error) {
  				ia->ia_dstaddr = oldaddr;
  				goto out;
  			}
  		}
  		if (ia->ia_flags & IFA_ROUTE) {
  			ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&oldaddr;
  			rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST);
  			ia->ia_ifa.ifa_dstaddr =
  					(struct sockaddr *)&ia->ia_dstaddr;
  			rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP);
  		}
  		goto out;
  
  	case SIOCSIFBRDADDR:
  		if ((ifp->if_flags & IFF_BROADCAST) == 0) {
  			error = EINVAL;
  			goto out;
  		}
  		ia->ia_broadaddr = *(struct sockaddr_in *)&ifr->ifr_broadaddr;
  		goto out;
  
  	case SIOCSIFADDR:
  		error = in_ifinit(ifp, ia,
  		    (struct sockaddr_in *) &ifr->ifr_addr, 1);
  		if (error != 0 && iaIsNew)
  			break;
  		if (error == 0) {
  			ii = ((struct in_ifinfo *)ifp->if_afdata[AF_INET]);
  			if (iaIsFirst &&
  			    (ifp->if_flags & IFF_MULTICAST) != 0) {
  				error = in_joingroup(ifp, &allhosts_addr,
  				    NULL, &ii->ii_allhosts);
  			}
  			EVENTHANDLER_INVOKE(ifaddr_event, ifp);
  		}
  		error = 0;
  		goto out;
  
  	case SIOCSIFNETMASK:
  		ia->ia_sockmask.sin_addr = ifra->ifra_addr.sin_addr;
  		ia->ia_subnetmask = ntohl(ia->ia_sockmask.sin_addr.s_addr);
  		goto out;
  
  	case SIOCAIFADDR:
  		maskIsNew = 0;
  		hostIsNew = 1;
  		error = 0;
  		if (ia->ia_addr.sin_family == AF_INET) {
  			if (ifra->ifra_addr.sin_len == 0) {
  				ifra->ifra_addr = ia->ia_addr;
  				hostIsNew = 0;
  			} else if (ifra->ifra_addr.sin_addr.s_addr ==
  					       ia->ia_addr.sin_addr.s_addr)
  				hostIsNew = 0;
  		}
  		if (ifra->ifra_mask.sin_len) {
  			/* 
  			 * QL: XXX
  			 * Need to scrub the prefix here in case
  			 * the issued command is SIOCAIFADDR with
  			 * the same address, but with a different
  			 * prefix length. And if the prefix length
  			 * is the same as before, then the call is 
  			 * un-necessarily executed here.
  			 */
  			in_ifscrub(ifp, ia, LLE_STATIC);
  			ia->ia_sockmask = ifra->ifra_mask;
  			ia->ia_sockmask.sin_family = AF_INET;
  			ia->ia_subnetmask =
  			     ntohl(ia->ia_sockmask.sin_addr.s_addr);
  			maskIsNew = 1;
  		}
  		if ((ifp->if_flags & IFF_POINTOPOINT) &&
  		    (ifra->ifra_dstaddr.sin_family == AF_INET)) {
  			in_ifscrub(ifp, ia, LLE_STATIC);
  			ia->ia_dstaddr = ifra->ifra_dstaddr;
  			maskIsNew  = 1; /* We lie; but the effect's the same */
  		}
  		if (ifra->ifra_addr.sin_family == AF_INET &&
  		    (hostIsNew || maskIsNew))
  			error = in_ifinit(ifp, ia, &ifra->ifra_addr, 0);
  		if (error != 0 && iaIsNew)
  			break;
  
  		if ((ifp->if_flags & IFF_BROADCAST) &&
  		    (ifra->ifra_broadaddr.sin_family == AF_INET))
  			ia->ia_broadaddr = ifra->ifra_broadaddr;
  		if (error == 0) {
  			ii = ((struct in_ifinfo *)ifp->if_afdata[AF_INET]);
  			if (iaIsFirst &&
  			    (ifp->if_flags & IFF_MULTICAST) != 0) {
  				error = in_joingroup(ifp, &allhosts_addr,
  				    NULL, &ii->ii_allhosts);
  			}
  			EVENTHANDLER_INVOKE(ifaddr_event, ifp);
  		}
  		goto out;
  
  	case SIOCDIFADDR:
  		/*
  		 * in_ifscrub kills the interface route.
  		 */
  		in_ifscrub(ifp, ia, LLE_STATIC);
  
  		/*
  		 * in_ifadown gets rid of all the rest of
  		 * the routes.  This is not quite the right
  		 * thing to do, but at least if we are running
  		 * a routing process they will come back.
  		 */
  		in_ifadown(&ia->ia_ifa, 1);
  		EVENTHANDLER_INVOKE(ifaddr_event, ifp);
  		error = 0;
  		break;
  
  	default:
  		panic("in_control: unsupported ioctl");
  	}
  
  	IF_ADDR_WLOCK(ifp);
  	/* Re-check that ia is still part of the list. */
  	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
  		if (ifa == &ia->ia_ifa)
  			break;
  	}
  	if (ifa == NULL) {
  		/*
  		 * If we lost the race with another thread, there is no need to
  		 * try it again for the next loop as there is no other exit
  		 * path between here and out.
  		 */
  		IF_ADDR_WUNLOCK(ifp);
  		error = EADDRNOTAVAIL;
  		goto out;
  	}
  	TAILQ_REMOVE(&ifp->if_addrhead, &ia->ia_ifa, ifa_link);
  	IF_ADDR_WUNLOCK(ifp);
  	ifa_free(&ia->ia_ifa);				/* if_addrhead */
  
  	IN_IFADDR_WLOCK();
  	TAILQ_REMOVE(&V_in_ifaddrhead, ia, ia_link);
  	if (ia->ia_addr.sin_family == AF_INET) {
  		struct in_ifaddr *if_ia;
  
  		LIST_REMOVE(ia, ia_hash);
  		IN_IFADDR_WUNLOCK();
  		/*
  		 * If this is the last IPv4 address configured on this
  		 * interface, leave the all-hosts group.
  		 * No state-change report need be transmitted.
  		 */
  		if_ia = NULL;
  		IFP_TO_IA(ifp, if_ia);
  		if (if_ia == NULL) {
  			ii = ((struct in_ifinfo *)ifp->if_afdata[AF_INET]);
  			IN_MULTI_LOCK();
  			if (ii->ii_allhosts) {
  				(void)in_leavegroup_locked(ii->ii_allhosts,
  				    NULL);
  				ii->ii_allhosts = NULL;
  			}
  			IN_MULTI_UNLOCK();
  		} else
  			ifa_free(&if_ia->ia_ifa);
  	} else
  		IN_IFADDR_WUNLOCK();
  	ifa_free(&ia->ia_ifa);				/* in_ifaddrhead */
  out:
  	if (ia != NULL)
  		ifa_free(&ia->ia_ifa);
  	return (error);
  }
  
  /*
   * SIOC[GAD]LIFADDR.
   *	SIOCGLIFADDR: get first address. (?!?)
   *	SIOCGLIFADDR with IFLR_PREFIX:
   *		get first address that matches the specified prefix.
   *	SIOCALIFADDR: add the specified address.
   *	SIOCALIFADDR with IFLR_PREFIX:
   *		EINVAL since we can't deduce hostid part of the address.
   *	SIOCDLIFADDR: delete the specified address.
   *	SIOCDLIFADDR with IFLR_PREFIX:
   *		delete the first address that matches the specified prefix.
   * return values:
   *	EINVAL on invalid parameters
   *	EADDRNOTAVAIL on prefix match failed/specified address not found
   *	other values may be returned from in_ioctl()
   */
  static int
  in_lifaddr_ioctl(struct socket *so, u_long cmd, caddr_t data,
      struct ifnet *ifp, struct thread *td)
  {
  	struct if_laddrreq *iflr = (struct if_laddrreq *)data;
  	struct ifaddr *ifa;
  
  	/* sanity checks */
  	if (data == NULL || ifp == NULL) {
  		panic("invalid argument to in_lifaddr_ioctl");
  		/*NOTRECHED*/
  	}
  
  	switch (cmd) {
  	case SIOCGLIFADDR:
  		/* address must be specified on GET with IFLR_PREFIX */
  		if ((iflr->flags & IFLR_PREFIX) == 0)
  			break;
  		/*FALLTHROUGH*/
  	case SIOCALIFADDR:
  	case SIOCDLIFADDR:
  		/* address must be specified on ADD and DELETE */
  		if (iflr->addr.ss_family != AF_INET)
  			return (EINVAL);
  		if (iflr->addr.ss_len != sizeof(struct sockaddr_in))
  			return (EINVAL);
  		/* XXX need improvement */
  		if (iflr->dstaddr.ss_family
  		 && iflr->dstaddr.ss_family != AF_INET)
  			return (EINVAL);
  		if (iflr->dstaddr.ss_family
  		 && iflr->dstaddr.ss_len != sizeof(struct sockaddr_in))
  			return (EINVAL);
  		break;
  	default: /*shouldn't happen*/
  		return (EOPNOTSUPP);
  	}
  	if (sizeof(struct in_addr) * 8 < iflr->prefixlen)
  		return (EINVAL);
  
  	switch (cmd) {
  	case SIOCALIFADDR:
  	    {
  		struct in_aliasreq ifra;
  
  		if (iflr->flags & IFLR_PREFIX)
  			return (EINVAL);
  
  		/* copy args to in_aliasreq, perform ioctl(SIOCAIFADDR). */
  		bzero(&ifra, sizeof(ifra));
  		bcopy(iflr->iflr_name, ifra.ifra_name,
  			sizeof(ifra.ifra_name));
  
  		bcopy(&iflr->addr, &ifra.ifra_addr, iflr->addr.ss_len);
  
  		if (iflr->dstaddr.ss_family) {	/*XXX*/
  			bcopy(&iflr->dstaddr, &ifra.ifra_dstaddr,
  				iflr->dstaddr.ss_len);
  		}
  
  		ifra.ifra_mask.sin_family = AF_INET;
  		ifra.ifra_mask.sin_len = sizeof(struct sockaddr_in);
  		in_len2mask(&ifra.ifra_mask.sin_addr, iflr->prefixlen);
  
  		return (in_control(so, SIOCAIFADDR, (caddr_t)&ifra, ifp, td));
  	    }
  	case SIOCGLIFADDR:
  	case SIOCDLIFADDR:
  	    {
  		struct in_ifaddr *ia;
  		struct in_addr mask, candidate, match;
  		struct sockaddr_in *sin;
  
  		bzero(&mask, sizeof(mask));
  		bzero(&match, sizeof(match));
  		if (iflr->flags & IFLR_PREFIX) {
  			/* lookup a prefix rather than address. */
  			in_len2mask(&mask, iflr->prefixlen);
  
  			sin = (struct sockaddr_in *)&iflr->addr;
  			match.s_addr = sin->sin_addr.s_addr;
  			match.s_addr &= mask.s_addr;
  
  			/* if you set extra bits, that's wrong */
  			if (match.s_addr != sin->sin_addr.s_addr)
  				return (EINVAL);
  
  		} else {
  			/* on getting an address, take the 1st match */
  			/* on deleting an address, do exact match */
  			if (cmd != SIOCGLIFADDR) {
  				in_len2mask(&mask, 32);
  				sin = (struct sockaddr_in *)&iflr->addr;
  				match.s_addr = sin->sin_addr.s_addr;
  			}
  		}
  
  		IF_ADDR_RLOCK(ifp);
  		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)	{
  			if (ifa->ifa_addr->sa_family != AF_INET)
  				continue;
  			if (match.s_addr == 0)
  				break;
  			candidate.s_addr = ((struct sockaddr_in *)&ifa->ifa_addr)->sin_addr.s_addr;
  			candidate.s_addr &= mask.s_addr;
  			if (candidate.s_addr == match.s_addr)
  				break;
  		}
  		if (ifa != NULL)
  			ifa_ref(ifa);
  		IF_ADDR_RUNLOCK(ifp);
  		if (ifa == NULL)
  			return (EADDRNOTAVAIL);
  		ia = (struct in_ifaddr *)ifa;
  
  		if (cmd == SIOCGLIFADDR) {
  			/* fill in the if_laddrreq structure */
  			bcopy(&ia->ia_addr, &iflr->addr, ia->ia_addr.sin_len);
  
  			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
  				bcopy(&ia->ia_dstaddr, &iflr->dstaddr,
  					ia->ia_dstaddr.sin_len);
  			} else
  				bzero(&iflr->dstaddr, sizeof(iflr->dstaddr));
  
  			iflr->prefixlen =
  				in_mask2len(&ia->ia_sockmask.sin_addr);
  
  			iflr->flags = 0;	/*XXX*/
  			ifa_free(ifa);
  
  			return (0);
  		} else {
  			struct in_aliasreq ifra;
  
  			/* fill in_aliasreq and do ioctl(SIOCDIFADDR) */
  			bzero(&ifra, sizeof(ifra));
  			bcopy(iflr->iflr_name, ifra.ifra_name,
  				sizeof(ifra.ifra_name));
  
  			bcopy(&ia->ia_addr, &ifra.ifra_addr,
  				ia->ia_addr.sin_len);
  			if ((ifp->if_flags & IFF_POINTOPOINT) != 0) {
  				bcopy(&ia->ia_dstaddr, &ifra.ifra_dstaddr,
  					ia->ia_dstaddr.sin_len);
  			}
  			bcopy(&ia->ia_sockmask, &ifra.ifra_dstaddr,
  				ia->ia_sockmask.sin_len);
  			ifa_free(ifa);
  
  			return (in_control(so, SIOCDIFADDR, (caddr_t)&ifra,
  			    ifp, td));
  		}
  	    }
  	}
  
  	return (EOPNOTSUPP);	/*just for safety*/
  }
  
  /*
   * Delete any existing route for an interface.
   */
  void
  in_ifscrub(struct ifnet *ifp, struct in_ifaddr *ia, u_int flags)
  {
  
  	in_scrubprefix(ia, flags);
  }
  
  /*
   * Initialize an interface's internet address
   * and routing table entry.
   */
  static int
  in_ifinit(struct ifnet *ifp, struct in_ifaddr *ia, struct sockaddr_in *sin,
      int scrub)
  {
  	register u_long i = ntohl(sin->sin_addr.s_addr);
  	struct sockaddr_in oldaddr;
  	int s = splimp(), flags = RTF_UP, error = 0;
  
  	oldaddr = ia->ia_addr;
  	if (oldaddr.sin_family == AF_INET)
  		LIST_REMOVE(ia, ia_hash);
  	ia->ia_addr = *sin;
  	if (ia->ia_addr.sin_family == AF_INET) {
  		IN_IFADDR_WLOCK();
  		LIST_INSERT_HEAD(INADDR_HASH(ia->ia_addr.sin_addr.s_addr),
  		    ia, ia_hash);
  		IN_IFADDR_WUNLOCK();
  	}
  	/*
  	 * Give the interface a chance to initialize
  	 * if this is its first address,
  	 * and to validate the address if necessary.
  	 */
  	if (ifp->if_ioctl != NULL) {
  		error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia);
  		if (error) {
  			splx(s);
  			/* LIST_REMOVE(ia, ia_hash) is done in in_control */
  			ia->ia_addr = oldaddr;
  			IN_IFADDR_WLOCK();
  			if (ia->ia_addr.sin_family == AF_INET)
  				LIST_INSERT_HEAD(INADDR_HASH(
  				    ia->ia_addr.sin_addr.s_addr), ia, ia_hash);
  			else 
  				/* 
  				 * If oldaddr family is not AF_INET (e.g. 
  				 * interface has been just created) in_control 
  				 * does not call LIST_REMOVE, and we end up 
  				 * with bogus ia entries in hash
  				 */
  				LIST_REMOVE(ia, ia_hash);
  			IN_IFADDR_WUNLOCK();
  			return (error);
  		}
  	}
  	splx(s);
  	if (scrub) {
  		ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr;
  		in_ifscrub(ifp, ia, LLE_STATIC);
  		ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
  	}
  	/*
  	 * Be compatible with network classes, if netmask isn't supplied,
  	 * guess it based on classes.
  	 */
  	if (ia->ia_subnetmask == 0) {
  		if (IN_CLASSA(i))
  			ia->ia_subnetmask = IN_CLASSA_NET;
  		else if (IN_CLASSB(i))
  			ia->ia_subnetmask = IN_CLASSB_NET;
  		else
  			ia->ia_subnetmask = IN_CLASSC_NET;
  		ia->ia_sockmask.sin_addr.s_addr = htonl(ia->ia_subnetmask);
  	}
  	ia->ia_subnet = i & ia->ia_subnetmask;
  	in_socktrim(&ia->ia_sockmask);
  	/*
  	 * XXX: carp(4) does not have interface route
  	 */
  	if (ifp->if_type == IFT_CARP)
  		return (0);
  	/*
  	 * Add route for the network.
  	 */
  	ia->ia_ifa.ifa_metric = ifp->if_metric;
  	if (ifp->if_flags & IFF_BROADCAST) {
  		if (ia->ia_subnetmask == IN_RFC3021_MASK)
  			ia->ia_broadaddr.sin_addr.s_addr = INADDR_BROADCAST;
  		else
  			ia->ia_broadaddr.sin_addr.s_addr =
  			    htonl(ia->ia_subnet | ~ia->ia_subnetmask);
  	} else if (ifp->if_flags & IFF_LOOPBACK) {
  		ia->ia_dstaddr = ia->ia_addr;
  		flags |= RTF_HOST;
  	} else if (ifp->if_flags & IFF_POINTOPOINT) {
  		if (ia->ia_dstaddr.sin_family != AF_INET)
  			return (0);
  		flags |= RTF_HOST;
  	}
  	if ((error = in_addprefix(ia, flags)) != 0)
  		return (error);
  
  	if (ia->ia_addr.sin_addr.s_addr == INADDR_ANY)
  		return (0);
  
  	if (ifp->if_flags & IFF_POINTOPOINT) {
  		if (ia->ia_dstaddr.sin_addr.s_addr == ia->ia_addr.sin_addr.s_addr)
  			return (0);
  	}
  
  
  	/*
  	 * add a loopback route to self
  	 */
  	if (V_useloopback && !(ifp->if_flags & IFF_LOOPBACK)) {
  		struct route ia_ro;
  
  		bzero(&ia_ro, sizeof(ia_ro));
  		*((struct sockaddr_in *)(&ia_ro.ro_dst)) = ia->ia_addr;
  		rtalloc_ign_fib(&ia_ro, 0, RT_DEFAULT_FIB);
  		if ((ia_ro.ro_rt != NULL) && (ia_ro.ro_rt->rt_ifp != NULL) &&
  		    (ia_ro.ro_rt->rt_ifp == V_loif)) {
  			RT_LOCK(ia_ro.ro_rt);
  			RT_ADDREF(ia_ro.ro_rt);
  			RTFREE_LOCKED(ia_ro.ro_rt);
  		} else
  			error = ifa_add_loopback_route((struct ifaddr *)ia, 
  				       (struct sockaddr *)&ia->ia_addr);
  		if (error == 0)
  			ia->ia_flags |= IFA_RTSELF;
  		if (ia_ro.ro_rt != NULL)
  			RTFREE(ia_ro.ro_rt);
  	}
  
  	return (error);
  }
  
  #define rtinitflags(x) \
  	((((x)->ia_ifp->if_flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) != 0) \
  	    ? RTF_HOST : 0)
  
  /*
   * Generate a routing message when inserting or deleting 
   * an interface address alias.
   */
  static void in_addralias_rtmsg(int cmd, struct in_addr *prefix, 
      struct in_ifaddr *target)
  {
  	struct route pfx_ro;
  	struct sockaddr_in *pfx_addr;
  	struct rtentry msg_rt;
  
  	/* QL: XXX
  	 * This is a bit questionable because there is no
  	 * additional route entry added/deleted for an address
  	 * alias. Therefore this route report is inaccurate.
  	 */
  	bzero(&pfx_ro, sizeof(pfx_ro));
  	pfx_addr = (struct sockaddr_in *)(&pfx_ro.ro_dst);
  	pfx_addr->sin_len = sizeof(*pfx_addr);
  	pfx_addr->sin_family = AF_INET;
  	pfx_addr->sin_addr = *prefix;
  	rtalloc_ign_fib(&pfx_ro, 0, 0);
  	if (pfx_ro.ro_rt != NULL) {
  		msg_rt = *pfx_ro.ro_rt;
  
  		/* QL: XXX
  		 * Point the gateway to the new interface
  		 * address as if a new prefix route entry has 
  		 * been added through the new address alias. 
  		 * All other parts of the rtentry is accurate, 
  		 * e.g., rt_key, rt_mask, rt_ifp etc.
  		 */
  		msg_rt.rt_gateway = 
  			(struct sockaddr *)&target->ia_addr;
  		rt_newaddrmsg(cmd, 
  			      (struct ifaddr *)target,
  			      0, &msg_rt);
  		RTFREE(pfx_ro.ro_rt);
  	}
  	return;
  }
  
  /*
   * Check if we have a route for the given prefix already or add one accordingly.
   */
  static int
  in_addprefix(struct in_ifaddr *target, int flags)
  {
  	struct in_ifaddr *ia;
  	struct in_addr prefix, mask, p, m;
  	int error;
  
  	if ((flags & RTF_HOST) != 0) {
  		prefix = target->ia_dstaddr.sin_addr;
  		mask.s_addr = 0;
  	} else {
  		prefix = target->ia_addr.sin_addr;
  		mask = target->ia_sockmask.sin_addr;
  		prefix.s_addr &= mask.s_addr;
  	}
  
  	IN_IFADDR_RLOCK();
  	TAILQ_FOREACH(ia, &V_in_ifaddrhead, ia_link) {
  		if (rtinitflags(ia)) {
  			p = ia->ia_dstaddr.sin_addr;
  
  			if (prefix.s_addr != p.s_addr)
  				continue;
  		} else {
  			p = ia->ia_addr.sin_addr;
  			m = ia->ia_sockmask.sin_addr;
  			p.s_addr &= m.s_addr;
  
  			if (prefix.s_addr != p.s_addr ||
  			    mask.s_addr != m.s_addr)
  				continue;
  		}
  
  		/*
  		 * If we got a matching prefix route inserted by other
  		 * interface address, we are done here.
  		 */
  		if (ia->ia_flags & IFA_ROUTE) {
  #ifdef RADIX_MPATH
  			if (ia->ia_addr.sin_addr.s_addr == 
  			    target->ia_addr.sin_addr.s_addr) {
  				IN_IFADDR_RUNLOCK();
  				return (EEXIST);
  			} else
  				break;
  #endif
  			if (V_sameprefixcarponly &&
  			    target->ia_ifp->if_type != IFT_CARP &&
  			    ia->ia_ifp->if_type != IFT_CARP) {
  				IN_IFADDR_RUNLOCK();
  				return (EEXIST);
  			} else {
  				in_addralias_rtmsg(RTM_ADD, &prefix, target);
  				IN_IFADDR_RUNLOCK();
  				return (0);
  			}
  		}
  	}
  	IN_IFADDR_RUNLOCK();
  
  	/*
  	 * No-one seem to have this prefix route, so we try to insert it.
  	 */
  	error = rtinit(&target->ia_ifa, (int)RTM_ADD, flags);
  	if (!error)
  		target->ia_flags |= IFA_ROUTE;
  	return (error);
  }
  
  extern void arp_ifscrub(struct ifnet *ifp, uint32_t addr);
  
  /*
   * If there is no other address in the system that can serve a route to the
   * same prefix, remove the route.  Hand over the route to the new address
   * otherwise.
   */
  static int
  in_scrubprefix(struct in_ifaddr *target, u_int flags)
  {
  	struct in_ifaddr *ia;
  	struct in_addr prefix, mask, p;
  	int error = 0;
  	struct sockaddr_in prefix0, mask0;
  
  	/*
  	 * Remove the loopback route to the interface address.
  	 * The "useloopback" setting is not consulted because if the
  	 * user configures an interface address, turns off this
  	 * setting, and then tries to delete that interface address,
  	 * checking the current setting of "useloopback" would leave
  	 * that interface address loopback route untouched, which
  	 * would be wrong. Therefore the interface address loopback route
  	 * deletion is unconditional.
  	 */
  	if ((target->ia_addr.sin_addr.s_addr != INADDR_ANY) &&
  	    !(target->ia_ifp->if_flags & IFF_LOOPBACK) &&
  	    (target->ia_flags & IFA_RTSELF)) {
  		struct route ia_ro;
  		int freeit = 0;
  
  		bzero(&ia_ro, sizeof(ia_ro));
  		*((struct sockaddr_in *)(&ia_ro.ro_dst)) = target->ia_addr;
  		rtalloc_ign_fib(&ia_ro, 0, 0);
  		if ((ia_ro.ro_rt != NULL) && (ia_ro.ro_rt->rt_ifp != NULL) &&
  		    (ia_ro.ro_rt->rt_ifp == V_loif)) {
  			RT_LOCK(ia_ro.ro_rt);
  			if (ia_ro.ro_rt->rt_refcnt <= 1)
  				freeit = 1;
  			else if (flags & LLE_STATIC) {
  				RT_REMREF(ia_ro.ro_rt);
  				target->ia_flags &= ~IFA_RTSELF;
  			}
  			RTFREE_LOCKED(ia_ro.ro_rt);
  		}
  		if (freeit && (flags & LLE_STATIC)) {
  			error = ifa_del_loopback_route((struct ifaddr *)target,
  				       (struct sockaddr *)&target->ia_addr);
  			if (error == 0)
  				target->ia_flags &= ~IFA_RTSELF;
  		}
  		if ((flags & LLE_STATIC) &&
  			!(target->ia_ifp->if_flags & IFF_NOARP))
  			/* remove arp cache */
  			arp_ifscrub(target->ia_ifp, IA_SIN(target)->sin_addr.s_addr);
  	}
  
  	if (rtinitflags(target))
  		prefix = target->ia_dstaddr.sin_addr;
  	else {
  		prefix = target->ia_addr.sin_addr;
  		mask = target->ia_sockmask.sin_addr;
  		prefix.s_addr &= mask.s_addr;
  	}
  
  	if ((target->ia_flags & IFA_ROUTE) == 0) {
  		in_addralias_rtmsg(RTM_DELETE, &prefix, target);
  		return (0);
  	}
  
  	IN_IFADDR_RLOCK();
  	TAILQ_FOREACH(ia, &V_in_ifaddrhead, ia_link) {
  		if (rtinitflags(ia))
  			p = ia->ia_dstaddr.sin_addr;
  		else {
  			p = ia->ia_addr.sin_addr;
  			p.s_addr &= ia->ia_sockmask.sin_addr.s_addr;
  		}
  
  		if ((prefix.s_addr != p.s_addr) ||
  		    !(ia->ia_ifp->if_flags & IFF_UP))
  			continue;
  
  		/*
  		 * If we got a matching prefix address, move IFA_ROUTE and
  		 * the route itself to it.  Make sure that routing daemons
  		 * get a heads-up.
  		 *
  		 * XXX: a special case for carp(4) interface - this should
  		 *      be more generally specified as an interface that
  		 *      doesn't support such action.
  		 */
  		if ((ia->ia_flags & IFA_ROUTE) == 0
  		    && (ia->ia_ifp->if_type != IFT_CARP)) {
  			ifa_ref(&ia->ia_ifa);
  			IN_IFADDR_RUNLOCK();
  			error = rtinit(&(target->ia_ifa), (int)RTM_DELETE,
  			    rtinitflags(target));
  			if (error == 0)
  				target->ia_flags &= ~IFA_ROUTE;
  			else
  				log(LOG_INFO, "in_scrubprefix: err=%d, old prefix delete failed\n",
  					error);
  			error = rtinit(&ia->ia_ifa, (int)RTM_ADD,
  			    rtinitflags(ia) | RTF_UP);
  			if (error == 0)
  				ia->ia_flags |= IFA_ROUTE;
  			else
  				log(LOG_INFO, "in_scrubprefix: err=%d, new prefix add failed\n",
  					error);
  			ifa_free(&ia->ia_ifa);
  			return (error);
  		}
  	}
  	IN_IFADDR_RUNLOCK();
  
  	/*
  	 * remove all L2 entries on the given prefix
  	 */
  	bzero(&prefix0, sizeof(prefix0));
  	prefix0.sin_len = sizeof(prefix0);
  	prefix0.sin_family = AF_INET;
  	prefix0.sin_addr.s_addr = target->ia_subnet;
  	bzero(&mask0, sizeof(mask0));
  	mask0.sin_len = sizeof(mask0);
  	mask0.sin_family = AF_INET;
  	mask0.sin_addr.s_addr = target->ia_subnetmask;
  	lltable_prefix_free(AF_INET, (struct sockaddr *)&prefix0, 
  			    (struct sockaddr *)&mask0, flags);
  
  	/*
  	 * As no-one seem to have this prefix, we can remove the route.
  	 */
  	error = rtinit(&(target->ia_ifa), (int)RTM_DELETE, rtinitflags(target));
  	if (error == 0)
  		target->ia_flags &= ~IFA_ROUTE;
  	else
  		log(LOG_INFO, "in_scrubprefix: err=%d, prefix delete failed\n", error);
  	return (error);
  }
  
  #undef rtinitflags
  
  /*
   * Return 1 if the address might be a local broadcast address.
   */
  int
  in_broadcast(struct in_addr in, struct ifnet *ifp)
  {
  	register struct ifaddr *ifa;
  	u_long t;
  
  	if (in.s_addr == INADDR_BROADCAST ||
  	    in.s_addr == INADDR_ANY)
  		return (1);
  	if ((ifp->if_flags & IFF_BROADCAST) == 0)
  		return (0);
  	t = ntohl(in.s_addr);
  	/*
  	 * Look through the list of addresses for a match
  	 * with a broadcast address.
  	 */
  #define ia ((struct in_ifaddr *)ifa)
  	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
  		if (ifa->ifa_addr->sa_family == AF_INET &&
  		    (in.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
  		     /*
  		      * Check for old-style (host 0) broadcast, but
  		      * taking into account that RFC 3021 obsoletes it.
  		      */
  		     (ia->ia_subnetmask != IN_RFC3021_MASK &&
  		     t == ia->ia_subnet)) &&
  		     /*
  		      * Check for an all one subnetmask. These
  		      * only exist when an interface gets a secondary
  		      * address.
  		      */
  		     ia->ia_subnetmask != (u_long)0xffffffff)
  			    return (1);
  	return (0);
  #undef ia
  }
  
  /*
   * On interface removal, clean up IPv4 data structures hung off of the ifnet.
   */
  void
  in_ifdetach(struct ifnet *ifp)
  {
  
  	in_pcbpurgeif0(&V_ripcbinfo, ifp);
  	in_pcbpurgeif0(&V_udbinfo, ifp);
  	in_purgemaddrs(ifp);
  }
  
  /*
   * Delete all IPv4 multicast address records, and associated link-layer
   * multicast address records, associated with ifp.
   * XXX It looks like domifdetach runs AFTER the link layer cleanup.
   * XXX This should not race with ifma_protospec being set during
   * a new allocation, if it does, we have bigger problems.
   */
  static void
  in_purgemaddrs(struct ifnet *ifp)
  {
  	LIST_HEAD(,in_multi) purgeinms;
  	struct in_multi		*inm, *tinm;
  	struct ifmultiaddr	*ifma;
  
  	LIST_INIT(&purgeinms);
  	IN_MULTI_LOCK();
  
  	/*
  	 * Extract list of in_multi associated with the detaching ifp
  	 * which the PF_INET layer is about to release.
  	 * We need to do this as IF_ADDR_LOCK() may be re-acquired
  	 * by code further down.
  	 */
  	IF_ADDR_RLOCK(ifp);
  	TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
  		if (ifma->ifma_addr->sa_family != AF_INET ||
  		    ifma->ifma_protospec == NULL)
  			continue;
  #if 0
  		KASSERT(ifma->ifma_protospec != NULL,
  		    ("%s: ifma_protospec is NULL", __func__));
  #endif
  		inm = (struct in_multi *)ifma->ifma_protospec;
  		LIST_INSERT_HEAD(&purgeinms, inm, inm_link);
  	}
  	IF_ADDR_RUNLOCK(ifp);
  
  	LIST_FOREACH_SAFE(inm, &purgeinms, inm_link, tinm) {
  		LIST_REMOVE(inm, inm_link);
  		inm_release_locked(inm);
  	}
  	igmp_ifdetach(ifp);
  
  	IN_MULTI_UNLOCK();
  }
  
  #include <net/if_dl.h>
  #include <netinet/if_ether.h>
  
  struct in_llentry {
  	struct llentry		base;
  	struct sockaddr_in	l3_addr4;
  };
  
  static struct llentry *
  in_lltable_new(const struct sockaddr *l3addr, u_int flags)
  {
  	struct in_llentry *lle;
  
  	lle = malloc(sizeof(struct in_llentry), M_LLTABLE, M_DONTWAIT | M_ZERO);
  	if (lle == NULL)		/* NB: caller generates msg */
  		return NULL;
  
  	callout_init(&lle->base.la_timer, CALLOUT_MPSAFE);
  	/*
  	 * For IPv4 this will trigger "arpresolve" to generate
  	 * an ARP request.
  	 */
  	lle->base.la_expire = time_uptime; /* mark expired */
  	lle->l3_addr4 = *(const struct sockaddr_in *)l3addr;
  	lle->base.lle_refcnt = 1;
  	LLE_LOCK_INIT(&lle->base);
  	return &lle->base;
  }
  
  /*
   * Deletes an address from the address table.
   * This function is called by the timer functions
   * such as arptimer() and nd6_llinfo_timer(), and
   * the caller does the locking.
   */
  static void
  in_lltable_free(struct lltable *llt, struct llentry *lle)
  {
  	LLE_WUNLOCK(lle);
  	LLE_LOCK_DESTROY(lle);
  	free(lle, M_LLTABLE);
  }
  
  
  #define IN_ARE_MASKED_ADDR_EQUAL(d, a, m)	(			\
  	    (((ntohl((d)->sin_addr.s_addr) ^ (a)->sin_addr.s_addr) & (m)->sin_addr.s_addr)) == 0 )
  
  static void
  in_lltable_prefix_free(struct lltable *llt, 
  		       const struct sockaddr *prefix,
  		       const struct sockaddr *mask,
  		       u_int flags)
  {
  	const struct sockaddr_in *pfx = (const struct sockaddr_in *)prefix;
  	const struct sockaddr_in *msk = (const struct sockaddr_in *)mask;
  	struct llentry *lle, *next;
  	register int i;
  	size_t pkts_dropped;
  
  	for (i=0; i < LLTBL_HASHTBL_SIZE; i++) {
  		LIST_FOREACH_SAFE(lle, &llt->lle_head[i], lle_next, next) {
  
  		        /* 
  			 * (flags & LLE_STATIC) means deleting all entries
  			 * including static ARP entries
  			 */
  			if (IN_ARE_MASKED_ADDR_EQUAL((struct sockaddr_in *)L3_ADDR(lle), 
  						     pfx, msk) &&
  			    ((flags & LLE_STATIC) || !(lle->la_flags & LLE_STATIC))) {
  				int canceled;
  
  				canceled = callout_drain(&lle->la_timer);
  				LLE_WLOCK(lle);
  				if (canceled)
  					LLE_REMREF(lle);
  				pkts_dropped = llentry_free(lle);
  				ARPSTAT_ADD(dropped, pkts_dropped);
  			}
  		}
  	}
  }
  
  
  static int
  in_lltable_rtcheck(struct ifnet *ifp, u_int flags, const struct sockaddr *l3addr)
  {
  	struct rtentry *rt;
  
  	KASSERT(l3addr->sa_family == AF_INET,
  	    ("sin_family %d", l3addr->sa_family));
  
  	/* XXX rtalloc1 should take a const param */
  	rt = rtalloc1(__DECONST(struct sockaddr *, l3addr), 0, 0);
  
  	if (rt == NULL)
  		return (EINVAL);
  
  	/*
  	 * If the gateway for an existing host route matches the target L3
  	 * address, which is a special route inserted by some implementation
  	 * such as MANET, and the interface is of the correct type, then
  	 * allow for ARP to proceed.
  	 */
  	if (rt->rt_flags & RTF_GATEWAY) {
  		if (!(rt->rt_flags & RTF_HOST) || !rt->rt_ifp ||
  			rt->rt_ifp->if_type != IFT_ETHER ||
  			  (rt->rt_ifp->if_flags & 
  			   (IFF_NOARP | IFF_STATICARP)) != 0 ||
  			  memcmp(rt->rt_gateway->sa_data, l3addr->sa_data,
  				 sizeof(in_addr_t)) != 0) {
  			RTFREE_LOCKED(rt);
  			return (EINVAL);
  		}
  	}
  
  	/*
  	 * Make sure that at least the destination address is covered 
  	 * by the route. This is for handling the case where 2 or more 
  	 * interfaces have the same prefix. An incoming packet arrives
  	 * on one interface and the corresponding outgoing packet leaves
  	 * another interface.
  	 */
  	if (!(rt->rt_flags & RTF_HOST) && rt->rt_ifp != ifp) {
  		const char *sa, *mask, *addr, *lim;
  		int len;
  
  		mask = (const char *)rt_mask(rt);
  		/*
  		 * Just being extra cautious to avoid some custom
  		 * code getting into trouble.
  		 */
  		if (mask == NULL) {
  			RTFREE_LOCKED(rt);
  			return (EINVAL);
  		}
  
  		sa = (const char *)rt_key(rt);
  		addr = (const char *)l3addr;
  		len = ((const struct sockaddr_in *)l3addr)->sin_len;
  		lim = addr + len;
  
  		for ( ; addr < lim; sa++, mask++, addr++) {
  			if ((*sa ^ *addr) & *mask) {
  #ifdef DIAGNOSTIC
  				log(LOG_INFO, "IPv4 address: \"%s\" is not on the network\n",
  				    inet_ntoa(((const struct sockaddr_in *)l3addr)->sin_addr));
  #endif
  				RTFREE_LOCKED(rt);
  				return (EINVAL);
  			}
  		}
  	}
  
  	RTFREE_LOCKED(rt);
  	return (0);
  }
  
  /*
   * Return NULL if not found or marked for deletion.
   * If found return lle read locked.
   */
  static struct llentry *
  in_lltable_lookup(struct lltable *llt, u_int flags, const struct sockaddr *l3addr)
  {
  	const struct sockaddr_in *sin = (const struct sockaddr_in *)l3addr;
  	struct ifnet *ifp = llt->llt_ifp;
  	struct llentry *lle;
  	struct llentries *lleh;
  	u_int hashkey;
  
  	IF_AFDATA_LOCK_ASSERT(ifp);
  	KASSERT(l3addr->sa_family == AF_INET,
  	    ("sin_family %d", l3addr->sa_family));
  
  	hashkey = sin->sin_addr.s_addr;
  	lleh = &llt->lle_head[LLATBL_HASH(hashkey, LLTBL_HASHMASK)];
  	LIST_FOREACH(lle, lleh, lle_next) {
  		struct sockaddr_in *sa2 = (struct sockaddr_in *)L3_ADDR(lle);
  		if (lle->la_flags & LLE_DELETED)
  			continue;
  		if (sa2->sin_addr.s_addr == sin->sin_addr.s_addr)
  			break;
  	}
  	if (lle == NULL) {
  #ifdef DIAGNOSTIC
  		if (flags & LLE_DELETE)
  			log(LOG_INFO, "interface address is missing from cache = %p  in delete\n", lle);	
  #endif
  		if (!(flags & LLE_CREATE))
  			return (NULL);
  		/*
  		 * A route that covers the given address must have
  		 * been installed 1st because we are doing a resolution,
  		 * verify this.
  		 */
  		if (!(flags & LLE_IFADDR) &&
  		    in_lltable_rtcheck(ifp, flags, l3addr) != 0)
  			goto done;
  
  		lle = in_lltable_new(l3addr, flags);
  		if (lle == NULL) {
  			log(LOG_INFO, "lla_lookup: new lle malloc failed\n");
  			goto done;
  		}
  		lle->la_flags = flags & ~LLE_CREATE;
  		if ((flags & (LLE_CREATE | LLE_IFADDR)) == (LLE_CREATE | LLE_IFADDR)) {
  			bcopy(IF_LLADDR(ifp), &lle->ll_addr, ifp->if_addrlen);
  			lle->la_flags |= (LLE_VALID | LLE_STATIC);
  		}
  
  		lle->lle_tbl  = llt;
  		lle->lle_head = lleh;
  		LIST_INSERT_HEAD(lleh, lle, lle_next);
  	} else if (flags & LLE_DELETE) {
  		if (!(lle->la_flags & LLE_IFADDR) || (flags & LLE_IFADDR)) {
  			LLE_WLOCK(lle);
  			lle->la_flags = LLE_DELETED;
  			EVENTHANDLER_INVOKE(arp_update_event, lle);
  			LLE_WUNLOCK(lle);
  #ifdef DIAGNOSTIC
  			log(LOG_INFO, "ifaddr cache = %p  is deleted\n", lle);	
  #endif
  		}
  		lle = (void *)-1;
  		
  	}
  	if (LLE_IS_VALID(lle)) {
  		if (flags & LLE_EXCLUSIVE)
  			LLE_WLOCK(lle);
  		else
  			LLE_RLOCK(lle);
  	}
  done:
  	return (lle);
  }
  
  static int
  in_lltable_dump(struct lltable *llt, struct sysctl_req *wr)
  {
  #define	SIN(lle)	((struct sockaddr_in *) L3_ADDR(lle))
  	struct ifnet *ifp = llt->llt_ifp;
  	struct llentry *lle;
  	/* XXX stack use */
  	struct {
  		struct rt_msghdr	rtm;
  		struct sockaddr_inarp	sin;
  		struct sockaddr_dl	sdl;
  	} arpc;
  	int error, i;
  
  	LLTABLE_LOCK_ASSERT();
  
  	error = 0;
  	for (i = 0; i < LLTBL_HASHTBL_SIZE; i++) {
  		LIST_FOREACH(lle, &llt->lle_head[i], lle_next) {
  			struct sockaddr_dl *sdl;
  			
  			/* skip deleted entries */
  			if ((lle->la_flags & LLE_DELETED) == LLE_DELETED)
  				continue;
  			/* Skip if jailed and not a valid IP of the prison. */
  			if (prison_if(wr->td->td_ucred, L3_ADDR(lle)) != 0)
  				continue;
  			/*
  			 * produce a msg made of:
  			 *  struct rt_msghdr;
  			 *  struct sockaddr_inarp; (IPv4)
  			 *  struct sockaddr_dl;
  			 */
  			bzero(&arpc, sizeof(arpc));
  			arpc.rtm.rtm_msglen = sizeof(arpc);
  			arpc.rtm.rtm_version = RTM_VERSION;
  			arpc.rtm.rtm_type = RTM_GET;
  			arpc.rtm.rtm_flags = RTF_UP;
  			arpc.rtm.rtm_addrs = RTA_DST | RTA_GATEWAY;
  			arpc.sin.sin_family = AF_INET;
  			arpc.sin.sin_len = sizeof(arpc.sin);
  			arpc.sin.sin_addr.s_addr = SIN(lle)->sin_addr.s_addr;
  
  			/* publish */
  			if (lle->la_flags & LLE_PUB) {
  				arpc.rtm.rtm_flags |= RTF_ANNOUNCE;
  				/* proxy only */
  				if (lle->la_flags & LLE_PROXY)
  					arpc.sin.sin_other = SIN_PROXY;
  			}
  
  			sdl = &arpc.sdl;
  			sdl->sdl_family = AF_LINK;
  			sdl->sdl_len = sizeof(*sdl);
  			sdl->sdl_index = ifp->if_index;
  			sdl->sdl_type = ifp->if_type;
  			if ((lle->la_flags & LLE_VALID) == LLE_VALID) {
  				sdl->sdl_alen = ifp->if_addrlen;
  				bcopy(&lle->ll_addr, LLADDR(sdl), ifp->if_addrlen);
  			} else {
  				sdl->sdl_alen = 0;
  				bzero(LLADDR(sdl), ifp->if_addrlen);
  			}
  
  			arpc.rtm.rtm_rmx.rmx_expire =
  			    lle->la_flags & LLE_STATIC ? 0 : lle->la_expire;
  			arpc.rtm.rtm_flags |= (RTF_HOST | RTF_LLDATA);
  			if (lle->la_flags & LLE_STATIC)
  				arpc.rtm.rtm_flags |= RTF_STATIC;
  			arpc.rtm.rtm_index = ifp->if_index;
  			error = SYSCTL_OUT(wr, &arpc, sizeof(arpc));
  			if (error)
  				break;
  		}
  	}
  	return error;
  #undef SIN
  }
  
  void *
  in_domifattach(struct ifnet *ifp)
  {
  	struct in_ifinfo *ii;
  	struct lltable *llt;
  
  	ii = malloc(sizeof(struct in_ifinfo), M_IFADDR, M_WAITOK|M_ZERO);
  
  	llt = lltable_init(ifp, AF_INET);
  	if (llt != NULL) {
  		llt->llt_free = in_lltable_free;
  		llt->llt_prefix_free = in_lltable_prefix_free;
  		llt->llt_lookup = in_lltable_lookup;
  		llt->llt_dump = in_lltable_dump;
  	}
  	ii->ii_llt = llt;
  
  	ii->ii_igmp = igmp_domifattach(ifp);
  
  	return ii;
  }
  
  void
  in_domifdetach(struct ifnet *ifp, void *aux)
  {
  	struct in_ifinfo *ii = (struct in_ifinfo *)aux;
  
  	igmp_domifdetach(ifp);
  	lltable_free(ii->ii_llt);
  	free(ii, M_IFADDR);
  }
  