source: rtems/cpukit/libnetworking/net/if.c @ 70148ee

/*
 * Copyright (c) 1980, 1986, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)if.c        8.5 (Berkeley) 1/9/95
 * $FreeBSD: src/sys/net/if.c,v 1.226 2005/04/15 01:51:26 cperciva Exp $
 */

/*
 * $Id$
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/param.h>
#include <rtems/bsd/sys/queue.h>
#include <sys/mbuf.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/protosw.h>
#include <sys/kernel.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <sys/syslog.h>
#include <sys/sysctl.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/if_var.h>
#include <net/radix.h>

/*
 * System initialization
 */

static int ifconf(u_long, caddr_t);
       void ifinit(void *);
static void if_qflush(struct ifqueue *);
static void if_slowtimo(void *);
static void link_rtrequest(int, struct rtentry *, struct sockaddr *);

SYSINIT(interfaces, SI_SUB_PROTO_IF, SI_ORDER_FIRST, ifinit, NULL)


int     ifqmaxlen = IFQ_MAXLEN;
struct  ifnet *ifnet;

/*
 * Network interface utility routines.
 *
 * Routines with ifa_ifwith* names take sockaddr *'s as
 * parameters.
 *
 * This routine assumes that it will be called at splimp() or higher.
 */
/* ARGSUSED*/
void
ifinit(void *dummy)
{
        struct ifnet *ifp;

        for (ifp = ifnet; ifp; ifp = ifp->if_next)
                if (ifp->if_snd.ifq_maxlen == 0)
                        ifp->if_snd.ifq_maxlen = ifqmaxlen;
        if_slowtimo(0);
}

int if_index = 0;
struct ifaddr **ifnet_addrs;


/*
 * Attach an interface to the
 * list of "active" interfaces.
 */
void
if_attach(struct ifnet *ifp)
{
        unsigned socksize, ifasize;
        int namelen, masklen;
        char workbuf[64];
        struct ifnet **p = &ifnet;
        struct sockaddr_dl *sdl;
        struct ifaddr *ifa;
        static int if_indexlim = 8;


        while (*p)
                p = &((*p)->if_next);
        *p = ifp;
        ifp->if_index = ++if_index;
        microtime(&ifp->if_lastchange);
        if (ifnet_addrs == 0 || if_index >= if_indexlim) {
                unsigned n = (if_indexlim <<= 1) * sizeof(ifa);
                struct ifaddr **q = (struct ifaddr **)
                                        malloc(n, M_IFADDR, M_WAITOK);
                bzero((caddr_t)q, n);
                if (ifnet_addrs) {
                        bcopy((caddr_t)ifnet_addrs, (caddr_t)q, n/2);
                        free((caddr_t)ifnet_addrs, M_IFADDR);
                }
                ifnet_addrs = q;
        }
        /*
         * create a Link Level name for this device
         */
        namelen = sprintf(workbuf, "%s%d", ifp->if_name, ifp->if_unit);
#define _offsetof(t, m) ((uintptr_t)((void*)&((t *)0)->m))
        masklen = _offsetof(struct sockaddr_dl, sdl_data[0]) + namelen;
        socksize = masklen + ifp->if_addrlen;
#define ROUNDUP(a) (1 + (((a) - 1) | (sizeof(long) - 1)))
        socksize = ROUNDUP(socksize);
        if (socksize < sizeof(*sdl))
                socksize = sizeof(*sdl);
        ifasize = sizeof(*ifa) + 2 * socksize;
        ifa = (struct ifaddr *)malloc(ifasize, M_IFADDR, M_WAITOK);
        if (ifa) {
                bzero((caddr_t)ifa, ifasize);
                sdl = (struct sockaddr_dl *)(ifa + 1);
                sdl->sdl_len = socksize;
                sdl->sdl_family = AF_LINK;
                bcopy(workbuf, sdl->sdl_data, namelen);
                sdl->sdl_nlen = namelen;
                sdl->sdl_index = ifp->if_index;
                sdl->sdl_type = ifp->if_type;
                ifnet_addrs[if_index - 1] = ifa;
                ifa->ifa_ifp = ifp;
                ifa->ifa_next = ifp->if_addrlist;
                ifa->ifa_rtrequest = link_rtrequest;
                ifp->if_addrlist = ifa;
                ifa->ifa_addr = (struct sockaddr *)sdl;

                sdl = (struct sockaddr_dl *)(socksize + (caddr_t)sdl);
                ifa->ifa_netmask = (struct sockaddr *)sdl;
                sdl->sdl_len = masklen;
                while (namelen != 0)
                        sdl->sdl_data[--namelen] = 0xff;
        }
}
/*
 * Locate an interface based on a complete address.
 */
/*ARGSUSED*/
struct ifaddr *
ifa_ifwithaddr(struct sockaddr *addr)
{
        struct ifnet *ifp;
        struct ifaddr *ifa;

#define equal(a1, a2) \
  (bcmp((caddr_t)(a1), (caddr_t)(a2), ((struct sockaddr *)(a1))->sa_len) == 0)
        for (ifp = ifnet; ifp; ifp = ifp->if_next)
            for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next) {
                if (ifa->ifa_addr->sa_family != addr->sa_family)
                        continue;
                if (equal(addr, ifa->ifa_addr))
                        return (ifa);
                if ((ifp->if_flags & IFF_BROADCAST) && ifa->ifa_broadaddr &&
                    equal(ifa->ifa_broadaddr, addr))
                        return (ifa);
        }
        return ((struct ifaddr *)0);
}
/*
 * Locate the point to point interface with a given destination address.
 */
/*ARGSUSED*/
struct ifaddr *
ifa_ifwithdstaddr(struct sockaddr *addr)
{
        struct ifnet *ifp;
        struct ifaddr *ifa;

        for (ifp = ifnet; ifp; ifp = ifp->if_next)
            if (ifp->if_flags & IFF_POINTOPOINT)
                for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next) {
                        if (ifa->ifa_addr->sa_family != addr->sa_family)
                                continue;
                        if (ifa->ifa_dstaddr && equal(addr, ifa->ifa_dstaddr))
                                return (ifa);
        }
        return ((struct ifaddr *)0);
}

/*
 * Find an interface on a specific network.  If many, choice
 * is most specific found.
 */
struct ifaddr *
ifa_ifwithnet(struct sockaddr *addr)
{
        struct ifnet *ifp;
        struct ifaddr *ifa;
        struct ifaddr *ifa_maybe = (struct ifaddr *) 0;
        u_int af = addr->sa_family;
        char *addr_data = addr->sa_data, *cplim;

        if (af == AF_LINK) {
            struct sockaddr_dl *sdl = (struct sockaddr_dl *)addr;
            if (sdl->sdl_index && sdl->sdl_index <= if_index)
                return (ifnet_addrs[sdl->sdl_index - 1]);
        }
        for (ifp = ifnet; ifp; ifp = ifp->if_next) {
                for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next) {
                        char *cp, *cp2, *cp3;

                        if (ifa->ifa_addr->sa_family != af)
                                next: continue;
                        if (ifp->if_flags & IFF_POINTOPOINT) {
                                if (ifa->ifa_dstaddr != 0
                                    && equal(addr, ifa->ifa_dstaddr))
                                        return (ifa);
                        } else {
                                /*
                                 * if we have a special address handler,
                                 * then use it instead of the generic one.
                                 */
                                if (ifa->ifa_claim_addr) {
                                        if ((*ifa->ifa_claim_addr)(ifa, addr)) {
                                                return (ifa);
                                        } else {
                                                continue;
                                        }
                                }

                                /*
                                 * Scan all the bits in the ifa's address.
                                 * If a bit dissagrees with what we are
                                 * looking for, mask it with the netmask
                                 * to see if it really matters.
                                 * (A byte at a time)
                                 */
                                if (ifa->ifa_netmask == 0)
                                        continue;
                                cp = addr_data;
                                cp2 = ifa->ifa_addr->sa_data;
                                cp3 = ifa->ifa_netmask->sa_data;
                                cplim = ifa->ifa_netmask->sa_len 
                                        + (char *)ifa->ifa_netmask;
                                while (cp3 < cplim)
                                        if ((*cp++ ^ *cp2++) & *cp3++)
                                                goto next; /* next address! */
                                /*
                                 * If the netmask of what we just found
                                 * is more specific than what we had before
                                 * (if we had one) then remember the new one
                                 * before continuing to search
                                 * for an even better one.
                                 */
                                if (ifa_maybe == 0 ||
                                    rn_refines((caddr_t)ifa->ifa_netmask,
                                    (caddr_t)ifa_maybe->ifa_netmask))
                                        ifa_maybe = ifa;
                        }
                }
        }
        return (ifa_maybe);
}

/*
 * Find an interface address specific to an interface best matching
 * a given address.
 */
struct ifaddr *
ifaof_ifpforaddr(struct sockaddr *addr, struct ifnet *ifp)
{
        struct ifaddr *ifa;
        char *cp, *cp2, *cp3;
        char *cplim;
        struct ifaddr *ifa_maybe = 0;
        u_int af = addr->sa_family;

        if (af >= AF_MAX)
                return (0);
        for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next) {
                if (ifa->ifa_addr->sa_family != af)
                        continue;
                if (ifa_maybe == 0)
                        ifa_maybe = ifa;
                if (ifa->ifa_netmask == 0) {
                        if (equal(addr, ifa->ifa_addr) ||
                            (ifa->ifa_dstaddr && equal(addr, ifa->ifa_dstaddr)))
                                return (ifa);
                        continue;
                }
                if (ifp->if_flags & IFF_POINTOPOINT) {
                        if (equal(addr, ifa->ifa_dstaddr))
                                return (ifa);
                } else {
                        cp = addr->sa_data;
                        cp2 = ifa->ifa_addr->sa_data;
                        cp3 = ifa->ifa_netmask->sa_data;
                        cplim = ifa->ifa_netmask->sa_len + (char *)ifa->ifa_netmask;
                        for (; cp3 < cplim; cp3++)
                                if ((*cp++ ^ *cp2++) & *cp3)
                                        break;
                        if (cp3 == cplim)
                                return (ifa);
                }
        }
        return (ifa_maybe);
}

#include <net/route.h>

/*
 * Default action when installing a route with a Link Level gateway.
 * Lookup an appropriate real ifa to point to.
 * This should be moved to /sys/net/link.c eventually.
 */
static void
link_rtrequest(int cmd, struct rtentry *rt, struct sockaddr *sa)
{
        struct ifaddr *ifa;
        struct sockaddr *dst;
        struct ifnet *ifp;

        if (cmd != RTM_ADD || ((ifa = rt->rt_ifa) == 0) ||
            ((ifp = ifa->ifa_ifp) == 0) || ((dst = rt_key(rt)) == 0))
                return;
        ifa = ifaof_ifpforaddr(dst, ifp);
        if (ifa) {
                IFAFREE(rt->rt_ifa);
                rt->rt_ifa = ifa;
                ifa->ifa_refcnt++;
                if (ifa->ifa_rtrequest && ifa->ifa_rtrequest != link_rtrequest)
                        ifa->ifa_rtrequest(cmd, rt, sa);
        }
}

/*
 * Mark an interface down and notify protocols of
 * the transition.
 * NOTE: must be called at splnet or eqivalent.
 */
void
if_down(struct ifnet *ifp)
{
        struct ifaddr *ifa;

        ifp->if_flags &= ~IFF_UP;
        microtime(&ifp->if_lastchange);
        for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
                pfctlinput(PRC_IFDOWN, ifa->ifa_addr);
        if_qflush(&ifp->if_snd);
        rt_ifmsg(ifp);
}

/*
 * Mark an interface up and notify protocols of
 * the transition.
 * NOTE: must be called at splnet or eqivalent.
 */
void
if_up(struct ifnet *ifp)
{

        ifp->if_flags |= IFF_UP;
        microtime(&ifp->if_lastchange);
#ifdef notyet
        struct ifaddr *ifa;
        /* this has no effect on IP, and will kill all iso connections XXX */
        for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
                pfctlinput(PRC_IFUP, ifa->ifa_addr);
#endif
        rt_ifmsg(ifp);
}

/*
 * Flush an interface queue.
 */
static void
if_qflush(struct ifqueue *ifq)
{
        struct mbuf *m, *n;

        n = ifq->ifq_head;
        while ((m = n) != 0) {
                n = m->m_act;
                m_freem(m);
        }
        ifq->ifq_head = 0;
        ifq->ifq_tail = 0;
        ifq->ifq_len = 0;
}

/*
 * Handle interface watchdog timer routines.  Called
 * from softclock, we decrement timers (if set) and
 * call the appropriate interface routine on expiration.
 */
static void
if_slowtimo(void *arg)
{
        struct ifnet *ifp;
        int s = splimp();

        for (ifp = ifnet; ifp; ifp = ifp->if_next) {
                if (ifp->if_timer == 0 || --ifp->if_timer)
                        continue;
                if (ifp->if_watchdog)
                        (*ifp->if_watchdog)(ifp);
        }
        splx(s);
        timeout(if_slowtimo, (void *)0, hz / IFNET_SLOWHZ);
}

/*
 * Map interface name to
 * interface structure pointer.
 */
struct ifnet *
ifunit(char *name)
{
        char *cp;
        struct ifnet *ifp;
        int unit;
        unsigned len;
        char *ep, c;

        for (cp = name; cp < name + IFNAMSIZ && *cp; cp++)
                if (*cp >= '0' && *cp <= '9')
                        break;
        if (*cp == '\0' || cp == name + IFNAMSIZ)
                return ((struct ifnet *)0);
        /*
         * Save first char of unit, and pointer to it,
         * so we can put a null there to avoid matching
         * initial substrings of interface names.
         */
        len = cp - name + 1;
        c = *cp;
        ep = cp;
        for (unit = 0; *cp >= '0' && *cp <= '9'; )
                unit = unit * 10 + *cp++ - '0';
        if (*cp != '\0')
                return 0;       /* no trailing garbage allowed */
        *ep = 0;
        for (ifp = ifnet; ifp; ifp = ifp->if_next) {
                if (bcmp(ifp->if_name, name, len))
                        continue;
                if (unit == ifp->if_unit)
                        break;
        }
        *ep = c;
        return (ifp);
}

/*
 * Interface ioctls.
 */
int
ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
{
        struct ifnet *ifp;
        struct ifreq *ifr;
        int error;

        switch (cmd) {

        case SIOCGIFCONF:
        case OSIOCGIFCONF:
                return (ifconf(cmd, data));
        }
        ifr = (struct ifreq *)data;
        ifp = ifunit(ifr->ifr_name);
        if (ifp == 0)
                return (ENXIO);
        switch (cmd) {

        case SIOCGIFFLAGS:
                ifr->ifr_flags = ifp->if_flags;
                break;

        case SIOCGIFMETRIC:
                ifr->ifr_metric = ifp->if_metric;
                break;

        case SIOCGIFMTU:
                ifr->ifr_mtu = ifp->if_mtu;
                break;

        case SIOCGIFPHYS:
                ifr->ifr_phys = ifp->if_physical;
                break;

        case SIOCSIFFLAGS:
                error = suser(p->p_ucred, &p->p_acflag);
                if (error)
                        return (error);
                if (ifp->if_flags & IFF_UP && (ifr->ifr_flags & IFF_UP) == 0) {
                        int s = splimp();
                        if_down(ifp);
                        splx(s);
                }
                if (ifr->ifr_flags & IFF_UP && (ifp->if_flags & IFF_UP) == 0) {
                        int s = splimp();
                        if_up(ifp);
                        splx(s);
                }
                ifp->if_flags = (ifp->if_flags & IFF_CANTCHANGE) |
                        (ifr->ifr_flags &~ IFF_CANTCHANGE);
                if (ifp->if_ioctl)
                        (void) (*ifp->if_ioctl)(ifp, cmd, data);
                microtime(&ifp->if_lastchange);
                break;

        case SIOCSIFMETRIC:
                error = suser(p->p_ucred, &p->p_acflag);
                if (error)
                        return (error);
                ifp->if_metric = ifr->ifr_metric;
                microtime(&ifp->if_lastchange);
                break;

        case SIOCSIFPHYS:
                error = suser(p->p_ucred, &p->p_acflag);
                if (error)
                        return error;
                if (!ifp->if_ioctl)
                        return EOPNOTSUPP;
                error = (*ifp->if_ioctl)(ifp, cmd, data);
                if (error == 0)
                        microtime(&ifp->if_lastchange);
                return(error);

        case SIOCSIFMTU:
                error = suser(p->p_ucred, &p->p_acflag);
                if (error)
                        return (error);
                if (ifp->if_ioctl == NULL)
                        return (EOPNOTSUPP);
                /*
                 * 72 was chosen below because it is the size of a TCP/IP
                 * header (40) + the minimum mss (32).
                 */
                if (ifr->ifr_mtu < 72 || ifr->ifr_mtu > 65535L)
                        return (EINVAL);
                error = (*ifp->if_ioctl)(ifp, cmd, data);
                if (error == 0)
                        microtime(&ifp->if_lastchange);
                return(error);

        case SIOCADDMULTI:
        case SIOCDELMULTI:
                error = suser(p->p_ucred, &p->p_acflag);
                if (error)
                        return (error);
                if (ifp->if_ioctl == NULL)
                        return (EOPNOTSUPP);
                error = (*ifp->if_ioctl)(ifp, cmd, data);
                if (error == 0 )
                        microtime(&ifp->if_lastchange);
                return(error);

        case SIOCSIFMEDIA:
                error = suser(p->p_ucred, &p->p_acflag);
                if (error)
                        return (error);
                if (ifp->if_ioctl == NULL)
                        return (EOPNOTSUPP);
                error = (*ifp->if_ioctl)(ifp, cmd, data);
                if (error == 0)
                        microtime(&ifp->if_lastchange);
                return error;

        case SIOCGIFMEDIA:
                if (ifp->if_ioctl == NULL)
                        return (EOPNOTSUPP);
                return ((*ifp->if_ioctl)(ifp, cmd, data));

        default:
                if (so->so_proto == 0)
                        return (EOPNOTSUPP);
#ifndef COMPAT_43
                return ((*so->so_proto->pr_usrreqs->pru_control)(so, cmd,
                                                                 data,
                                                                 ifp));
#else
            {
                int ocmd = cmd;

                switch (cmd) {

                case SIOCSIFDSTADDR:
                case SIOCSIFADDR:
                case SIOCSIFBRDADDR:
                case SIOCSIFNETMASK:
#if BYTE_ORDER != BIG_ENDIAN
                        if (ifr->ifr_addr.sa_family == 0 &&
                            ifr->ifr_addr.sa_len < 16) {
                                ifr->ifr_addr.sa_family = ifr->ifr_addr.sa_len;
                                ifr->ifr_addr.sa_len = 16;
                        }
#else
                        if (ifr->ifr_addr.sa_len == 0)
                                ifr->ifr_addr.sa_len = 16;
#endif
                        break;

                case OSIOCGIFADDR:
                        cmd = SIOCGIFADDR;
                        break;

                case OSIOCGIFDSTADDR:
                        cmd = SIOCGIFDSTADDR;
                        break;

                case OSIOCGIFBRDADDR:
                        cmd = SIOCGIFBRDADDR;
                        break;

                case OSIOCGIFNETMASK:
                        cmd = SIOCGIFNETMASK;
                }
                error =  ((*so->so_proto->pr_usrreqs->pru_control)(so,
                                                                   cmd,
                                                                   data,
                                                                   ifp));
                switch (ocmd) {

                case OSIOCGIFADDR:
                case OSIOCGIFDSTADDR:
                case OSIOCGIFBRDADDR:
                case OSIOCGIFNETMASK:
                        *(u_short *)&ifr->ifr_addr = ifr->ifr_addr.sa_family;
                }
                return (error);

            }
#endif

        /*
         * RTEMS additions for setting/getting `tap' function
         */
        case SIOCSIFTAP:
                ifp->if_tap = ifr->ifr_tap;
                return 0;

        case SIOCGIFTAP:
                ifr->ifr_tap = ifp->if_tap;
                return 0;
        }
        return (0);
}

/*
 * Set/clear promiscuous mode on interface ifp based on the truth value
 * of pswitch.  The calls are reference counted so that only the first
 * "on" request actually has an effect, as does the final "off" request.
 * Results are undefined if the "off" and "on" requests are not matched.
 */
int
ifpromisc(struct ifnet *ifp, int pswitch)
{
        struct ifreq ifr;

        if (pswitch) {
                /*
                 * If the device is not configured up, we cannot put it in
                 * promiscuous mode.
                 */
                if ((ifp->if_flags & IFF_UP) == 0)
                        return (ENETDOWN);
                if (ifp->if_pcount++ != 0)
                        return (0);
                ifp->if_flags |= IFF_PROMISC;
                log(LOG_INFO, "%s%d: promiscuous mode enabled\n",
                    ifp->if_name, ifp->if_unit);
        } else {
                if (--ifp->if_pcount > 0)
                        return (0);
                ifp->if_flags &= ~IFF_PROMISC;
        }
        ifr.ifr_flags = ifp->if_flags;
        return ((*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, (caddr_t)&ifr));
}

/*
 * Return interface configuration
 * of system.  List may be used
 * in later ioctl's (above) to get
 * other information.
 */
/*ARGSUSED*/
static int
ifconf(u_long cmd, caddr_t data)
{
        struct ifconf *ifc = (struct ifconf *)data;
        struct ifnet *ifp = ifnet;
        struct ifaddr *ifa;
        struct ifreq ifr, *ifrp;
        char              *ifrpc;
        int space = ifc->ifc_len, error = 0;

        ifrpc = (char*)ifc->ifc_req;
        for (; space > sizeof (ifr) && ifp; ifp = ifp->if_next) {
                char workbuf[64];
                int ifnlen;

                ifnlen = sprintf(workbuf, "%s%d", ifp->if_name, ifp->if_unit);
                if(ifnlen + 1 > sizeof ifr.ifr_name) {
                        error = ENAMETOOLONG;
                } else {
                        strcpy(ifr.ifr_name, workbuf);
                }

                if ((ifa = ifp->if_addrlist) == 0) {
                        bzero((caddr_t)&ifr.ifr_addr, sizeof(ifr.ifr_addr));
                        error = copyout((caddr_t)&ifr, (caddr_t)ifrpc,
                            sizeof (ifr));
                        if (error)
                                break;
                        space -= sizeof (ifr); ifrpc+=sizeof(ifr);
                } else
                    for ( ; space > sizeof (ifr) && ifa; ifa = ifa->ifa_next) {
                        struct sockaddr *sa = ifa->ifa_addr;
#ifdef COMPAT_43
                        if (cmd == OSIOCGIFCONF) {
                                struct osockaddr *osa =
                                         (struct osockaddr *)&ifr.ifr_addr;
                                ifr.ifr_addr = *sa;
                                osa->sa_family = sa->sa_family;
                                error = copyout((caddr_t)&ifr, (caddr_t)ifrpc,
                                                sizeof (ifr));
                                ifrpc+=sizeof(ifr);
                        } else
#endif
                        if (sa->sa_len <= sizeof(*sa)) {
                                ifr.ifr_addr = *sa;
                                error = copyout((caddr_t)&ifr, (caddr_t)ifrpc,
                                                sizeof (ifr));
                                ifrpc+=sizeof(ifr);
                        } else {
                                space -= sa->sa_len - sizeof(*sa);
                                if (space < sizeof (ifr))
                                        break;
                                error = copyout((caddr_t)&ifr, (caddr_t)ifrpc,
                                                sizeof (ifr.ifr_name));
                                ifrpc+=sizeof(ifr.ifr_name);
                                if (error == 0)
                                    error = copyout((caddr_t)sa,
                                      (caddr_t)ifrpc, sa->sa_len);
                                ifrpc += sa->sa_len;
                        }
                        if (error)
                                break;
                        space -= sizeof (ifr);
                }
        }
        ifc->ifc_len -= space;
        return (error);
}

SYSCTL_NODE(_net, PF_LINK, link, CTLFLAG_RW, 0, "Link layers");
SYSCTL_NODE(_net_link, 0, generic, CTLFLAG_RW, 0, "Generic link-management");