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//==========================================================================

//

//      sys/netinet/if_ether.c

//

//     

//

//==========================================================================

//####BSDCOPYRIGHTBEGIN####

//

// -------------------------------------------

//

// Portions of this software may have been derived from OpenBSD or other sources,

// and are covered by the appropriate copyright disclaimers included herein.

//

// -------------------------------------------

//

//####BSDCOPYRIGHTEND####

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):    gthomas

// Contributors: gthomas

// Date:         2000-01-10

// Purpose:      

// Description:  

//              

//

//####DESCRIPTIONEND####

//

//==========================================================================

/*      $OpenBSD: if_ether.c,v 1.19 1999/11/10 18:48:47 chris Exp $     */

/*      $NetBSD: if_ether.c,v 1.31 1996/05/11 12:59:58 mycroft Exp $    */

/*

 * 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. 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_ether.c  8.1 (Berkeley) 6/10/93

 */

/*

 * Ethernet address resolution protocol.

 * TODO:

 *      add "inuse/lock" bit (or ref. count) along with valid bit

 */

#include <sys/param.h>

#ifndef __ECOS

#include <sys/systm.h>

#endif

#include <sys/malloc.h>

#include <sys/mbuf.h>

#include <sys/socket.h>

#include <sys/time.h>

#include <sys/kernel.h>

#include <sys/errno.h>

#include <sys/ioctl.h>

#ifndef __ECOS

#include <sys/syslog.h>

#include <sys/proc.h>

#endif

#ifdef INET

#include <net/if.h>

#include <net/if_dl.h>

#include <net/route.h>

#include <netinet/in.h>

#include <netinet/in_systm.h>

#include <netinet/in_var.h>

#include <netinet/ip.h>

#include <netinet/if_ether.h>

#define SIN(s) ((struct sockaddr_in *)s)

#define SDL(s) ((struct sockaddr_dl *)s)

#define SRP(s) ((struct sockaddr_inarp *)s)

/*

 * ARP trailer negotiation.  Trailer protocol is not IP specific,

 * but ARP request/response use IP addresses.

 */

#define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL

/* timer values */

int     arpt_prune = (5*60*1);  /* walk list every 5 minutes */

int     arpt_keep = (20*60);    /* once resolved, good for 20 more minutes */

int     arpt_down = 20;         /* once declared down, don't send for 20 secs */

#define rt_expire rt_rmx.rmx_expire

static  void arprequest

            __P((struct arpcom *, u_int32_t *, u_int32_t *, u_int8_t *));

static  void arptfree __P((struct llinfo_arp *));

static  void arptimer __P((void *));

static  struct llinfo_arp *arplookup __P((u_int32_t, int, int));

static  void in_arpinput __P((struct mbuf *));

extern  struct ifnet loif;

LIST_HEAD(, llinfo_arp) llinfo_arp;

struct  ifqueue arpintrq = {0, 0, 0, 50};

int     arp_inuse, arp_allocated, arp_intimer;

int     arp_maxtries = 5;

int     useloopback = 1;        /* use loopback interface for local traffic */

int     arpinit_done = 0;

/* revarp state */

static struct in_addr myip, srv_ip;

static int myip_initialized = 0;

static int revarp_in_progress = 0;

struct ifnet *myip_ifp = NULL;

static void arptimer __P((void *));

static void arprequest __P((struct arpcom *, u_int32_t *, u_int32_t *,

                            u_int8_t *));

static void in_arpinput __P((struct mbuf *));

static void arptfree __P((struct llinfo_arp *));

static struct llinfo_arp *arplookup __P((u_int32_t, int, int ));

#ifdef DDB

#include <vm/vm.h>

static void db_print_sa __P((struct sockaddr *));

static void db_print_ifa __P((struct ifaddr *));

static void db_print_llinfo __P((caddr_t));

static int db_show_radix_node __P((struct radix_node *, void *));

#endif

/*

 * Timeout routine.  Age arp_tab entries periodically.

 */

/* ARGSUSED */

static void

arptimer(arg)

        void *arg;

{

        int s;

        register struct llinfo_arp *la, *nla;

        s = splsoftnet();

        timeout(arptimer, NULL, arpt_prune * hz);

        for (la = llinfo_arp.lh_first; la != 0; la = nla) {

                register struct rtentry *rt = la->la_rt;

                nla = la->la_list.le_next;

                if (rt->rt_expire && rt->rt_expire <= time.tv_sec)

                        arptfree(la); /* timer has expired; clear */

        }

        splx(s);

}

/*

 * Parallel to llc_rtrequest.

 */

void

arp_rtrequest(req, rt, sa)

        int req;

        register struct rtentry *rt;

        struct sockaddr *sa;

{

        register struct sockaddr *gate = rt->rt_gateway;

        register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo;

        static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};

        if (!arpinit_done) {

                arpinit_done = 1;

                /*

                 * We generate expiration times from time.tv_sec

                 * so avoid accidently creating permanent routes.

                 */

                if (time.tv_sec == 0) {

                        time.tv_sec++;

                }

                timeout(arptimer, (caddr_t)0, hz);

        }

        if (rt->rt_flags & RTF_GATEWAY)

                return;

        switch (req) {

        case RTM_ADD:

                /*

                 * 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 &&

                    SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)

                        rt->rt_flags |= RTF_CLONING;

                if (rt->rt_flags & RTF_CLONING) {

                        /*

                         * Case 1: This route should come from a route to iface.

                         */

                        rt_setgate(rt, rt_key(rt),

                                        (struct sockaddr *)&null_sdl);

                        gate = rt->rt_gateway;

                        SDL(gate)->sdl_type = rt->rt_ifp->if_type;

                        SDL(gate)->sdl_index = rt->rt_ifp->if_index;

                        /*

                         * Give this route an expiration time, even though

                         * it's a "permanent" route, so that routes cloned

                         * from it do not need their expiration time set.

                         */

                        rt->rt_expire = time.tv_sec;

                        break;

                }

                /* Announce a new entry if requested. */

                if (rt->rt_flags & RTF_ANNOUNCE)

                        arprequest((struct arpcom *)rt->rt_ifp,

                            &SIN(rt_key(rt))->sin_addr.s_addr,

                            &SIN(rt_key(rt))->sin_addr.s_addr,

                            (u_char *)LLADDR(SDL(gate)));

                /*FALLTHROUGH*/

        case RTM_RESOLVE:

                if (gate->sa_family != AF_LINK ||

                    gate->sa_len < sizeof(null_sdl)) {

#ifdef __ECOS

#else

                        log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n");

#endif

                        break;

                }

                SDL(gate)->sdl_type = rt->rt_ifp->if_type;

                SDL(gate)->sdl_index = rt->rt_ifp->if_index;

                if (la != 0)

                        break; /* This happens on a route change */

                /*

                 * Case 2:  This route may come from cloning, or a manual route

                 * add with a LL address.

                 */

                R_Malloc(la, struct llinfo_arp *, sizeof(*la));

                rt->rt_llinfo = (caddr_t)la;

                if (la == 0) {

#ifdef __ECOS

#else

                        log(LOG_DEBUG, "arp_rtrequest: malloc failed\n");

#endif

                        break;

                }

                arp_inuse++, arp_allocated++;

                Bzero(la, sizeof(*la));

                la->la_rt = rt;

                rt->rt_flags |= RTF_LLINFO;

                LIST_INSERT_HEAD(&llinfo_arp, la, la_list);

                if (SIN(rt_key(rt))->sin_addr.s_addr ==

                    (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) {

                        /*

                         * This test used to be

                         *      if (loif.if_flags & IFF_UP)

                         * It allowed local traffic to be forced through

                         * the hardware by configuring the loopback down.

                         * However, it causes problems during network

                         * configuration for boards that can't receive

                         * packets they send.  It is now necessary to clear

                         * "useloopback" and remove the route to force

                         * traffic out to the hardware.

                         */

                        rt->rt_expire = 0;

                        Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr,

                            LLADDR(SDL(gate)),

                            SDL(gate)->sdl_alen = ETHER_ADDR_LEN);

                        if (useloopback)

                                rt->rt_ifp = &loif;

                }

                break;

        case RTM_DELETE:

                if (la == 0)

                        break;

                arp_inuse--;

                LIST_REMOVE(la, la_list);

                rt->rt_llinfo = 0;

                rt->rt_flags &= ~RTF_LLINFO;

                if (la->la_hold)

                        m_freem(la->la_hold);

                Free((caddr_t)la);

        }

}

/*

 * Broadcast an ARP request. Caller specifies:

 *      - arp header source ip address

 *      - arp header target ip address

 *      - arp header source ethernet address

 */

static void

arprequest(ac, sip, tip, enaddr)

        register struct arpcom *ac;

        register u_int32_t *sip, *tip;

        register u_int8_t *enaddr;

{

        register struct mbuf *m;

        register struct ether_header *eh;

        register struct ether_arp *ea;

        struct sockaddr sa;

        if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)

                return;

        m->m_len = sizeof(*ea);

        m->m_pkthdr.len = sizeof(*ea);

        MH_ALIGN(m, sizeof(*ea));

        ea = mtod(m, struct ether_arp *);

        eh = (struct ether_header *)sa.sa_data;

        bzero((caddr_t)ea, sizeof (*ea));

        bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost,

            sizeof(eh->ether_dhost));

        eh->ether_type = htons(ETHERTYPE_ARP);  /* if_output will not swap */

        ea->arp_hrd = htons(ARPHRD_ETHER);

        ea->arp_pro = htons(ETHERTYPE_IP);

        ea->arp_hln = sizeof(ea->arp_sha);      /* hardware address length */

        ea->arp_pln = sizeof(ea->arp_spa);      /* protocol address length */

        ea->arp_op = htons(ARPOP_REQUEST);

        bcopy((caddr_t)enaddr, (caddr_t)eh->ether_shost,

              sizeof(eh->ether_shost));

        bcopy((caddr_t)enaddr, (caddr_t)ea->arp_sha, sizeof(ea->arp_sha));

        bcopy((caddr_t)sip, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa));

        bcopy((caddr_t)tip, (caddr_t)ea->arp_tpa, sizeof(ea->arp_tpa));

        sa.sa_family = AF_UNSPEC;

        sa.sa_len = sizeof(sa);

        (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0);

}

/*

 * 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 1 indicates

 * that desten has been filled in and the packet should be sent

 * normally; a 0 return indicates that the packet has been

 * taken over here, either now or for later transmission.

 */

int

arpresolve(ac, rt, m, dst, desten)

        register struct arpcom *ac;

        register struct rtentry *rt;

        struct mbuf *m;

        register struct sockaddr *dst;

        register u_char *desten;

{

        register struct llinfo_arp *la;

        struct sockaddr_dl *sdl;

        if (m->m_flags & M_BCAST) {     /* broadcast */

                bcopy((caddr_t)etherbroadcastaddr, (caddr_t)desten,

                    sizeof(etherbroadcastaddr));

                return (1);

        }

        if (m->m_flags & M_MCAST) {     /* multicast */

                ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);

                return (1);

        }

        if (rt)

                la = (struct llinfo_arp *)rt->rt_llinfo;

        else {

                if ((la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0)) != NULL)

                        rt = la->la_rt;

        }

        if (la == 0 || rt == 0) {

#ifdef __ECOS

#else

                log(LOG_DEBUG, "arpresolve: can't allocate llinfo\n");

#endif

                m_freem(m);

                return (0);

        }

        sdl = SDL(rt->rt_gateway);

        /*

         * Check the address family and length is valid, the address

         * is resolved; otherwise, try to resolve.

         */

        if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) &&

            sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {

                bcopy(LLADDR(sdl), desten, sdl->sdl_alen);

                return 1;

        }

        if (((struct ifnet *)ac)->if_flags & IFF_NOARP)

                return 0;

        /*

         * There is an arptab entry, but no ethernet address

         * response yet.  Replace the held mbuf with this

         * latest one.

         */

        if (la->la_hold)

                m_freem(la->la_hold);

        la->la_hold = m;

        /*

         * Re-send the ARP request when appropriate.

         */

#ifdef  DIAGNOSTIC

        if (rt->rt_expire == 0) {

                /* This should never happen. (Should it? -gwr) */

                printf("arpresolve: unresolved and rt_expire == 0\n");

                /* Set expiration time to now (expired). */

                rt->rt_expire = time.tv_sec;

        }

#endif

        if (rt->rt_expire) {

                rt->rt_flags &= ~RTF_REJECT;

                if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) {

                        rt->rt_expire = time.tv_sec;

                        if (la->la_asked++ < arp_maxtries)

                                arprequest(ac,

                                    &(SIN(rt->rt_ifa->ifa_addr)->sin_addr.s_addr),

                                    &(SIN(dst)->sin_addr.s_addr),

                                    ac->ac_enaddr);

                        else {

                                rt->rt_flags |= RTF_REJECT;

                                rt->rt_expire += arpt_down;

                                la->la_asked = 0;

                        }

                }

        }

        return (0);

}

/*

 * Common length and type checks are done here,

 * then the protocol-specific routine is called.

 */

void

arpintr()

{

        register struct mbuf *m;

        register struct arphdr *ar;

        int s;

        while (arpintrq.ifq_head) {

                s = splimp();

                IF_DEQUEUE(&arpintrq, m);

                splx(s);

                if (m == 0 || (m->m_flags & M_PKTHDR) == 0)

                        panic("arpintr");

                if (m->m_len >= sizeof(struct arphdr) &&

                    (ar = mtod(m, struct arphdr *)) &&

                    ntohs(ar->ar_hrd) == ARPHRD_ETHER &&

                    m->m_len >=

                      sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln))

                        switch (ntohs(ar->ar_pro)) {

                        case ETHERTYPE_IP:

                        case ETHERTYPE_IPTRAILERS:

                                in_arpinput(m);

                                continue;

                        }

                m_freem(m);

        }

}

/*

 * ARP for Internet protocols on 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(m)

        struct mbuf *m;

{

        register struct ether_arp *ea;

        register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif;

        struct ether_header *eh;

        register struct llinfo_arp *la = 0;

        register struct rtentry *rt;

        struct in_ifaddr *ia, *maybe_ia = 0;

        struct sockaddr_dl *sdl;

        struct sockaddr sa;

        struct in_addr isaddr, itaddr, myaddr;

        int op;

        ea = mtod(m, struct ether_arp *);

        op = ntohs(ea->arp_op);

        bcopy((caddr_t)ea->arp_spa, (caddr_t)&isaddr, sizeof (isaddr));

        bcopy((caddr_t)ea->arp_tpa, (caddr_t)&itaddr, sizeof (itaddr));

        for (ia = in_ifaddr.tqh_first; ia != 0; ia = ia->ia_list.tqe_next)

                if (ia->ia_ifp == &ac->ac_if ||

                    (ia->ia_ifp->if_bridge &&

                    ia->ia_ifp->if_bridge == ac->ac_if.if_bridge)) {

                        maybe_ia = ia;

                        if (itaddr.s_addr == ia->ia_addr.sin_addr.s_addr ||

                            isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)

                                break;

                }

        if (maybe_ia == 0)

                goto out;

        myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr;

        if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr,

            sizeof (ea->arp_sha)))

                goto out;       /* it's from me, ignore it. */

        if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr,

            sizeof (ea->arp_sha))) {

#ifdef __ECOS

#else

                log(LOG_ERR,

                    "arp: ether address is broadcast for IP address %s!\n",

                    inet_ntoa(isaddr));

#endif

                goto out;

        }

        if (isaddr.s_addr == myaddr.s_addr) {

#ifdef __ECOS

#else

                log(LOG_ERR,

                   "duplicate IP address %s sent from ethernet address %s\n",

                   inet_ntoa(isaddr), ether_sprintf(ea->arp_sha));

#endif

                itaddr = myaddr;

                goto reply;

        }

        la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0);

        if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) {

                if (sdl->sdl_alen &&

                    bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) {

                        if (rt->rt_flags & RTF_PERMANENT_ARP) {

#ifdef __ECOS

#else

                                log(LOG_WARNING,

                                   "arp: attempt to overwrite permanent "

                                   "entry for %s by %s on %s\n",

                                   inet_ntoa(isaddr),

                                   ether_sprintf(ea->arp_sha),

                                   (&ac->ac_if)->if_xname);

#endif

                                goto out;

                        } else if (rt->rt_ifp != &ac->ac_if) {

#ifdef __ECOS

#else

                                log(LOG_WARNING,

                                   "arp: attempt to overwrite entry for %s "

                                   "on %s by %s on %s\n",

                                   inet_ntoa(isaddr), rt->rt_ifp->if_xname,

                                   ether_sprintf(ea->arp_sha),

                                   (&ac->ac_if)->if_xname);

#endif

                                goto out;

                        } else {

#ifdef __ECOS

#else

                                log(LOG_INFO,

                                   "arp info overwritten for %s by %s on %s\n",

                                   inet_ntoa(isaddr),

                                   ether_sprintf(ea->arp_sha),

                                   (&ac->ac_if)->if_xname);

#endif

                                rt->rt_expire = 1; /* no longer static */

                        }

                }

                bcopy((caddr_t)ea->arp_sha, LLADDR(sdl),

                    sdl->sdl_alen = sizeof(ea->arp_sha));

                if (rt->rt_expire)

                        rt->rt_expire = time.tv_sec + arpt_keep;

                rt->rt_flags &= ~RTF_REJECT;

                la->la_asked = 0;

                if (la->la_hold) {

                        (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold,

                                rt_key(rt), rt);

                        la->la_hold = 0;

                }

        }

reply:

        if (op != ARPOP_REQUEST) {

        out:

                m_freem(m);

                return;

        }

        if (itaddr.s_addr == myaddr.s_addr) {

                /* I am the target */

                bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha,

                    sizeof(ea->arp_sha));

                bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_sha,

                    sizeof(ea->arp_sha));

        } else {

                la = arplookup(itaddr.s_addr, 0, SIN_PROXY);

                if (la == 0)

                        goto out;

                rt = la->la_rt;

                bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha,

                    sizeof(ea->arp_sha));

                sdl = SDL(rt->rt_gateway);

                bcopy(LLADDR(sdl), (caddr_t)ea->arp_sha, sizeof(ea->arp_sha));

        }

        bcopy((caddr_t)ea->arp_spa, (caddr_t)ea->arp_tpa, sizeof(ea->arp_spa));

        bcopy((caddr_t)&itaddr, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa));

        ea->arp_op = htons(ARPOP_REPLY);

        ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */

        eh = (struct ether_header *)sa.sa_data;

        bcopy((caddr_t)ea->arp_tha, (caddr_t)eh->ether_dhost,

            sizeof(eh->ether_dhost));

        bcopy((caddr_t)ac->ac_enaddr, (caddr_t)eh->ether_shost,

            sizeof(eh->ether_shost));

        eh->ether_type = htons(ETHERTYPE_ARP);

        sa.sa_family = AF_UNSPEC;

        sa.sa_len = sizeof(sa);

        (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0);

        return;

}

/*

 * Free an arp entry.

 */

static void

arptfree(la)

        register struct llinfo_arp *la;

{

        register struct rtentry *rt = la->la_rt;

        register struct sockaddr_dl *sdl;