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[thirdparty/dhcp.git] / common / dlpi.c

/* dlpi.c
 
   Data Link Provider Interface (DLPI) network interface code. */

/*
 * Copyright (c) 1996-1999 Internet Software Consortium.
 * Use is subject to license terms which appear in the file named
 * ISC-LICENSE that should have accompanied this file when you
 * received it.   If a file named ISC-LICENSE did not accompany this
 * file, or you are not sure the one you have is correct, you may
 * obtain an applicable copy of the license at:
 *
 *             http://www.isc.org/isc-license-1.0.html. 
 *
 * This file is part of the ISC DHCP distribution.   The documentation
 * associated with this file is listed in the file DOCUMENTATION,
 * included in the top-level directory of this release.
 *
 * Support and other services are available for ISC products - see
 * http://www.isc.org for more information.
 *
 * This software was written for the Internet Software Consortium
 * by Eric James Negaard, <lmdejn@lmd.ericsson.se>.  To learn more about
 * the Internet Software Consortium, see ``http://www.vix.com/isc''.
 */

/*
 * Based largely in part to the existing NIT code in nit.c.
 *
 * This code has been developed and tested on sparc-based machines running
 * SunOS 5.5.1, with le and hme network interfaces.  It should be pretty
 * generic, though.
 */

/*
 * Implementation notes:
 *
 * I first tried to write this code to the "vanilla" DLPI 2.0 API.
 * It worked on a Sun Ultra-1 with a hme interface, but didn't work
 * on Sun SparcStation 5's with "le" interfaces (the packets sent out
 * via dlpiunitdatareq contained an Ethernet type of 0x0000 instead
 * of the expected 0x0800).
 *
 * Therefore I added the "DLPI_RAW" code which is a Sun extension to
 * the DLPI standard.  This code works on both of the above machines.
 * This is configurable in the OS-dependent include file by defining
 * USE_DLPI_RAW.
 *
 * It quickly became apparant that I should also use the "pfmod"
 * STREAMS module to cut down on the amount of user level packet
 * processing.  I don't know how widely available "pfmod" is, so it's
 * use is conditionally included. This is configurable in the
 * OS-dependent include file by defining USE_DLPI_PFMOD.
 *
 * A major quirk on the Sun's at least, is that no packets seem to get
 * sent out the interface until six seconds after the interface is
 * first "attached" to [per system reboot] (it's actually from when
 * the interface is attached, not when it is plumbed, so putting a
 * sleep into the dhclient-script at PREINIT time doesn't help).  I
 * HAVE tried, without success to poll the fd to see when it is ready
 * for writing.  This doesn't help at all. If the sleeps are not done,
 * the initial DHCPREQUEST or DHCPDISCOVER never gets sent out, so
 * I've put them here, when register_send and register_receive are
 * called (split up into two three-second sleeps between the notices,
 * so that it doesn't seem like so long when you're watching :-).  The
 * amount of time to sleep is configurable in the OS-dependent include
 * file by defining DLPI_FIRST_SEND_WAIT to be the number of seconds
 * to sleep.
 */

#include "dhcpd.h"

#if defined (USE_DLPI_SEND) || defined (USE_DLPI_RECEIVE)

# include <sys/ioctl.h>
# include <sys/time.h>
# include <sys/dlpi.h>
# include <stropts.h>
# ifdef USE_DLPI_PFMOD
#  include <sys/pfmod.h>
# endif
# ifdef USE_POLL
#  include <poll.h>
# endif

# include <netinet/in_systm.h>
# include "includes/netinet/ip.h"
# include "includes/netinet/udp.h"
# include "includes/netinet/if_ether.h"

# ifdef USE_DLPI_PFMOD
#  ifdef USE_DLPI_RAW
#   define DLPI_MODNAME "DLPI+RAW+PFMOD"
#  else
#   define DLPI_MODNAME "DLPI+PFMOD"
#  endif
# else
#  ifdef USE_DLPI_RAW
#   define DLPI_MODNAME "DLPI+RAW"
#  else
#   define DLPI_MODNAME "DLPI"
#  endif
# endif

# ifndef ABS
#  define ABS(x) ((x) >= 0 ? (x) : 0-(x))
# endif

#ifndef lint
static char copyright[] =
"$Id: dlpi.c,v 1.8 1999/03/16 05:50:33 mellon Exp $ Copyright (c) 1998, 1999 The Internet Software Consortium.  All rights reserved.\n";
#endif /* not lint */

static int strioctl PROTO ((int fd, int cmd, int timeout, int len, char *dp));

#define DLPI_MAXDLBUF           8192    /* Buffer size */
#define DLPI_MAXDLADDR          1024    /* Max address size */
#define DLPI_DEVDIR             "/dev/" /* Device directory */
#define DLPI_DEFAULTSAP         0x0800  /* IP protocol */

static void dlpi_makeaddr PROTO ((unsigned char *physaddr, int physaddrlen,
                                  unsigned char *sap, int saplen,
                                  unsigned char *buf));
static void dlpi_parseaddr PROTO ((unsigned char *buf,
                                   unsigned char *physaddr,
                                   int physaddrlen, unsigned char *sap,
                                   int saplen));
static int dlpiopen PROTO ((char *ifname));
static int dlpiunit PROTO ((char *ifname));
static int dlpiinforeq PROTO ((int fd));
static int dlpiphysaddrreq PROTO ((int fd, unsigned long addrtype));
static int dlpiattachreq PROTO ((int fd, unsigned long ppa));
static int dlpibindreq PROTO ((int fd, unsigned long sap, unsigned long max_conind,
                               unsigned long service_mode, unsigned long conn_mgmt,
                               unsigned long xidtest));
static int dlpidetachreq PROTO ((int fd));
static int dlpiunbindreq PROTO ((int fd));
static int dlpiokack PROTO ((int fd, char *bufp));
static int dlpiinfoack PROTO ((int fd, char *bufp));
static int dlpiphysaddrack PROTO ((int fd, char *bufp));
static int dlpibindack PROTO ((int fd, char *bufp));
static int dlpiunitdatareq PROTO ((int fd, unsigned char *addr,
                                   int addrlen, unsigned long minpri,
                                   unsigned long maxpri, unsigned char *data,
                                   int datalen));
static int dlpiunitdataind PROTO ((int fd,
                                   unsigned char *dstaddr,
                                   unsigned long *dstaddrlen,
                                   unsigned char *srcaddr,
                                   unsigned long *srcaddrlen,
                                   unsigned long *grpaddr,
                                   unsigned char *data,
                                   int datalen));

# ifndef USE_POLL
static void     sigalrm PROTO ((int sig));
# endif
static int      expected PROTO ((unsigned long prim, union DL_primitives *dlp,
                                  int msgflags));
static int      strgetmsg PROTO ((int fd, struct strbuf *ctlp,
                                  struct strbuf *datap, int *flagsp,
                                  char *caller));

/* Reinitializes the specified interface after an address change.   This
   is not required for packet-filter APIs. */

#ifdef USE_DLPI_SEND
void if_reinitialize_send (info)
        struct interface_info *info;
{
}
#endif

#ifdef USE_DLPI_RECEIVE
void if_reinitialize_receive (info)
        struct interface_info *info;
{
}
#endif

/* Called by get_interface_list for each interface that's discovered.
   Opens a packet filter for each interface and adds it to the select
   mask. */

int if_register_dlpi (info)
        struct interface_info *info;
{
        int sock;
        int unit;
        long buf [DLPI_MAXDLBUF];
        union DL_primitives *dlp;

        dlp = (union DL_primitives *)buf;

        /* Open a DLPI device */
        if ((sock = dlpiopen (info -> name)) < 0) {
            log_fatal ("Can't open DLPI device for %s: %m", info -> name);
        }

        /*
         * Get information about the provider.
         */

        /*
         * Submit a DL_INFO_REQ request, to find
         * the dl_mac_type and dl_provider_style
         */
        if (dlpiinforeq(sock) < 0 || dlpiinfoack(sock, (char *)buf) < 0) {
            log_fatal ("Can't get DLPI MAC type for %s: %m", info -> name);
        } else {
            switch (dlp -> info_ack.dl_mac_type) {
              case DL_CSMACD: /* IEEE 802.3 */
              case DL_ETHER:
                info -> hw_address.htype = HTYPE_ETHER;
                break;
              case DL_FDDI:
                info -> hw_address.htype = HTYPE_FDDI;
                break;
              default:
                log_fatal ("%s: unknown DLPI MAC type %d",
                       info -> name,
                       dlp -> info_ack.dl_mac_type);
                break;
            }
        }

        if (dlp -> info_ack.dl_provider_style == DL_STYLE2) {
            /*
             * Attach to the device.  If this fails, the device
             * does not exist.
             */
            unit = dlpiunit (info -> name);
        
            if (dlpiattachreq (sock, unit) < 0
                || dlpiokack (sock, (char *)buf) < 0) {
                log_fatal ("Can't attach DLPI device for %s: %m", info -> name);
            }
        }

        /*
         * Bind to the IP service access point (SAP), connectionless (CLDLS).
         */
        if (dlpibindreq (sock, DLPI_DEFAULTSAP, 0, DL_CLDLS, 0, 0) < 0
            || dlpibindack (sock, (char *)buf) < 0) {
            log_fatal ("Can't bind DLPI device for %s: %m", info -> name);
        }

        /*
         * Submit a DL_PHYS_ADDR_REQ request, to find
         * the hardware address
         */
        if (dlpiphysaddrreq (sock, DL_CURR_PHYS_ADDR) < 0
            || dlpiphysaddrack (sock, (char *)buf) < 0) {
            log_fatal ("Can't get DLPI hardware address for %s: %m",
                   info -> name);
        }

        info -> hw_address.hlen = dlp -> physaddr_ack.dl_addr_length;
        memcpy (info -> hw_address.haddr,
                (char *)buf + dlp -> physaddr_ack.dl_addr_offset,
                dlp -> physaddr_ack.dl_addr_length);

#ifdef USE_DLPI_RAW
        if (strioctl (sock, DLIOCRAW, INFTIM, 0, 0) < 0) {
            log_fatal ("Can't set DLPI RAW mode for %s: %m",
                   info -> name);
        }
#endif

#ifdef USE_DLPI_PFMOD
        if (ioctl (sock, I_PUSH, "pfmod") < 0) {
            log_fatal ("Can't push packet filter onto DLPI for %s: %m",
                   info -> name);
        }
#endif

        return sock;
}

static int
strioctl (fd, cmd, timeout, len, dp)
int fd;
int cmd;
int timeout;
int len;
char *dp;
{
    struct strioctl sio;
    int rslt;

    sio.ic_cmd = cmd;
    sio.ic_timout = timeout;
    sio.ic_len = len;
    sio.ic_dp = dp;

    if ((rslt = ioctl (fd, I_STR, &sio)) < 0) {
        return rslt;
    } else {
        return sio.ic_len;
    }
}

#ifdef USE_DLPI_SEND
void if_register_send (info)
        struct interface_info *info;
{
        /* If we're using the DLPI API for sending and receiving,
           we don't need to register this interface twice. */
#ifndef USE_DLPI_RECEIVE
# ifdef USE_DLPI_PFMOD
        struct packetfilt pf;
# endif

        info -> wfdesc = if_register_dlpi (info);

# ifdef USE_DLPI_PFMOD
        /* Set up an PFMOD filter that rejects everything... */
        pf.Pf_Priority = 0;
        pf.Pf_FilterLen = 1;
        pf.Pf_Filter [0] = ENF_PUSHZERO;

        /* Install the filter */
        if (strioctl (info -> wfdesc, PFIOCSETF, INFTIM,
                      sizeof (pf), (char *)&pf) < 0) {
            log_fatal ("Can't set PFMOD send filter on %s: %m", info -> name);
        }

# endif /* USE_DLPI_PFMOD */
#else /* !defined (USE_DLPI_RECEIVE) */
        /*
         * If using DLPI for both send and receive, simply re-use
         * the read file descriptor that was set up earlier.
         */
        info -> wfdesc = info -> rfdesc;
#endif

        if (!quiet_interface_discovery)
                log_info ("Sending on   DLPI/%s/%s%s%s",
                      info -> name,
                      print_hw_addr (info -> hw_address.htype,
                                     info -> hw_address.hlen,
                                     info -> hw_address.haddr),
                      (info -> shared_network ? "/" : ""),
                      (info -> shared_network ?
                       info -> shared_network -> name : ""));

#ifdef DLPI_FIRST_SEND_WAIT
/* See the implementation notes at the beginning of this file */
# ifdef USE_DLPI_RECEIVE
        sleep (DLPI_FIRST_SEND_WAIT - (DLPI_FIRST_SEND_WAIT / 2));
# else
        sleep (DLPI_FIRST_SEND_WAIT);
# endif
#endif
}
#endif /* USE_DLPI_SEND */

#ifdef USE_DLPI_RECEIVE
/* Packet filter program...
   XXX Changes to the filter program may require changes to the constant
   offsets used in if_register_send to patch the NIT program! XXX */

void if_register_receive (info)
        struct interface_info *info;
{
#ifdef USE_DLPI_PFMOD
        struct packetfilt pf;
#endif

        /* Open a DLPI device and hang it on this interface... */
        info -> rfdesc = if_register_dlpi (info);

#ifdef USE_DLPI_PFMOD
        /* Set up the PFMOD filter program. */
        /* XXX Unlike the BPF filter program, this one won't work if the
           XXX IP packet is fragmented or if there are options on the IP
           XXX header. */
        pf.Pf_Priority = 0;
        pf.Pf_FilterLen = 0;

#ifdef USE_DLPI_RAW
        pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 6;
        pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT + ENF_CAND;
        pf.Pf_Filter [pf.Pf_FilterLen++] = htons (ETHERTYPE_IP);
        pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT;
        pf.Pf_Filter [pf.Pf_FilterLen++] = htons (IPPROTO_UDP);
        pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 11;
        pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSH00FF + ENF_AND;
        pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_CAND;
        pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 18;
        pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT + ENF_CAND;
        pf.Pf_Filter [pf.Pf_FilterLen++] = htons (local_port);
#else
        /*
         * The packets that will be received on this file descriptor
         * will be IP packets (due to the SAP that was specified in
         * the dlbind call).  There will be no ethernet header.
         * Therefore, setup the packet filter to check the protocol
         * field for UDP, and the destination port number equal
         * to the local port.  All offsets are relative to the start
         * of an IP packet.
         */
        pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT;
        pf.Pf_Filter [pf.Pf_FilterLen++] = htons (IPPROTO_UDP);
        pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 4;
        pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSH00FF + ENF_AND;
        pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_CAND;
        pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHWORD + 11;
        pf.Pf_Filter [pf.Pf_FilterLen++] = ENF_PUSHLIT + ENF_CAND;
        pf.Pf_Filter [pf.Pf_FilterLen++] = htons (local_port);
#endif

        /* Install the filter... */
        if (strioctl (info -> rfdesc, PFIOCSETF, INFTIM,
                      sizeof (pf), (char *)&pf) < 0) {
            log_fatal ("Can't set PFMOD receive filter on %s: %m", info -> name);
        }
#endif

        if (!quiet_interface_discovery)
                log_info ("Listening on DLPI/%s/%s%s%s",
                      info -> name,
                      print_hw_addr (info -> hw_address.htype,
                                     info -> hw_address.hlen,
                                     info -> hw_address.haddr),
                      (info -> shared_network ? "/" : ""),
                      (info -> shared_network ?
                       info -> shared_network -> name : ""));

#ifdef DLPI_FIRST_SEND_WAIT
/* See the implementation notes at the beginning of this file */
# ifdef USE_DLPI_SEND
        sleep (DLPI_FIRST_SEND_WAIT / 2);
# else
        sleep (DLPI_FIRST_SEND_WAIT);
# endif
#endif
}
#endif /* USE_DLPI_RECEIVE */

#ifdef USE_DLPI_SEND
ssize_t send_packet (interface, packet, raw, len, from, to, hto)
        struct interface_info *interface;
        struct packet *packet;
        struct dhcp_packet *raw;
        size_t len;
        struct in_addr from;
        struct sockaddr_in *to;
        struct hardware *hto;
{
        int dbuflen;
        unsigned char dbuf [1536];
        unsigned char sap [2];
        unsigned char dstaddr [DLPI_MAXDLADDR];
        unsigned addrlen;
        int saplen;
        int result;

        if (!strcmp (interface -> name, "fallback"))
                return send_fallback (interface, packet, raw,
                                      len, from, to, hto);

        dbuflen = 0;

        /* Assemble the headers... */
#ifdef USE_DLPI_RAW
        assemble_hw_header (interface, dbuf, &dbuflen, hto);
#endif
        assemble_udp_ip_header (interface, dbuf, &dbuflen, from.s_addr,
                                to -> sin_addr.s_addr, to -> sin_port,
                                (unsigned char *)raw, len);

        /* Copy the data into the buffer (yuk). */
        memcpy (dbuf + dbuflen, raw, len);
        dbuflen += len;

#ifdef USE_DLPI_RAW
        result = write (interface -> wfdesc, dbuf, dbuflen);
#else
        /* XXX: Assumes ethernet, with two byte SAP */
        sap [0] = 0x08;         /* ETHERTYPE_IP, high byte */
        sap [1] = 0x0;          /* ETHERTYPE_IP, low byte */
        saplen = -2;            /* -2 indicates a two byte SAP at the end
                                   of the address */

        /* Setup the destination address */
        if (hto && hto -> hlen == interface -> hw_address.hlen) {
            dlpi_makeaddr (hto -> haddr, hto -> hlen, sap, saplen, dstaddr);
        } else {
            /* XXX: Assumes broadcast addr is all ones */
            /* Really should get the broadcast address as part of the
             * dlpiinforeq, and store it somewhere in the interface structure.
             */
            unsigned char bcast_ether [DLPI_MAXDLADDR];

            memset ((char *)bcast_ether, 0xFF, interface -> hw_address.hlen);
            dlpi_makeaddr (bcast_ether, interface -> hw_address.hlen,
                         sap, saplen, dstaddr);
        }
        addrlen = interface -> hw_address.hlen + ABS (saplen);

        /* Send the packet down the wire... */
        result = dlpiunitdatareq (interface -> wfdesc, dstaddr, addrlen,
                                  0, 0, dbuf, dbuflen);
#endif
        if (result < 0)
                warn ("send_packet: %m");
        return result;
}
#endif /* USE_DLPI_SEND */

#ifdef USE_DLPI_RECEIVE
ssize_t receive_packet (interface, buf, len, from, hfrom)
        struct interface_info *interface;
        unsigned char *buf;
        size_t len;
        struct sockaddr_in *from;
        struct hardware *hfrom;
{
        unsigned char dbuf [1536];
        unsigned char sap [2];
        unsigned char srcaddr [DLPI_MAXDLADDR];
        unsigned long srcaddrlen;
        int saplen;
        int flags = 0;
        int length = 0;
        int offset = 0;
        int rslt;
        int bufix = 0;
        
#ifdef USE_DLPI_RAW
        length = read (interface -> rfdesc, dbuf, sizeof (dbuf));
#else   
        length = dlpiunitdataind (interface -> rfdesc, (unsigned char *)NULL,
                                  (unsigned long *)NULL, srcaddr, &srcaddrlen,
                                  (unsigned long *)NULL, dbuf, sizeof (dbuf));
#endif

        if (length <= 0) {
            return length;
        }

#ifndef USE_DLPI_RAW
        /* Copy sender info */
        /* XXX: Assumes ethernet, where SAP comes at end of haddr */
        saplen = -2;
        if (hfrom && srcaddrlen == ABS(saplen) + interface -> hw_address.hlen) {
            hfrom -> htype = interface -> hw_address.htype;
            hfrom -> hlen = interface -> hw_address.hlen;
            dlpi_parseaddr (srcaddr, hfrom -> haddr,
                            interface -> hw_address.hlen, sap, saplen);
        } else if (hfrom) {
            memset ((char *)hfrom, '\0', sizeof (*hfrom));
        }
#endif

        /* Decode the IP and UDP headers... */
        bufix = 0;
#ifdef USE_DLPI_RAW
        /* Decode the physical header... */
        offset = decode_hw_header (interface, dbuf, bufix, hfrom);

        /* If a physical layer checksum failed (dunno of any
           physical layer that supports this, but WTH), skip this
           packet. */
        if (offset < 0) {
                return 0;
        }
        bufix += offset;
        length -= offset;
#endif
        offset = decode_udp_ip_header (interface, dbuf, bufix,
                                       from, (unsigned char *)0, length);

        /* If the IP or UDP checksum was bad, skip the packet... */
        if (offset < 0) {
            return 0;
        }

        bufix += offset;
        length -= offset;

        /* Copy out the data in the packet... */
        memcpy (buf, &dbuf [bufix], length);
        return length;
}
#endif

/* Common DLPI routines ...
 *
 * Written by Eric James Negaard, <lmdejn@lmd.ericsson.se>
 *
 * Based largely in part to the example code contained in the document
 * "How to Use the STREAMS Data Link Provider Interface (DLPI)", written
 * by Neal Nuckolls of SunSoft Internet Engineering.
 * 
 * This code has been developed and tested on sparc-based machines running
 * SunOS 5.5.1, with le and hme network interfaces.  It should be pretty
 * generic, though.
 * 
 * The usual disclaimers apply.  This code works for me.  Don't blame me
 * if it makes your machine or network go down in flames.  That taken
 * into consideration, use this code as you wish.  If you make usefull
 * modifications I'd appreciate hearing about it.
 */

#define DLPI_MAXWAIT            15      /* Max timeout */

static void dlpi_makeaddr (physaddr, physaddrlen, sap, saplen, buf)
        unsigned char *physaddr;
        int physaddrlen;
        unsigned char *sap;
        int saplen;
        unsigned char *buf;
{
        /*
         * If the saplen is negative, the SAP goes at the end of the address,
         * otherwise it goes at the beginning.
         */
        if (saplen >= 0) {
                memcpy ((char *)buf, (char *)sap, saplen);
                memcpy ((char *)&buf [saplen], (char *)physaddr, physaddrlen);
        } else {
                memcpy ((char *)buf, (char *)physaddr, physaddrlen);
                memcpy ((char *)&buf [physaddrlen], (char *)sap, 0 - saplen);
        }
}

static void dlpi_parseaddr (buf, physaddr, physaddrlen, sap, saplen)
        unsigned char *buf;
        unsigned char *physaddr;
        int physaddrlen;
        unsigned char *sap;
        int saplen;
{
        /*
         * If the saplen is negative, the SAP is at the end of the address,
         * otherwise it is at the beginning.
         */
        if (saplen >= 0) {
                memcpy ((char *)sap, (char *)buf, saplen);
                memcpy ((char *)physaddr, (char *)&buf [saplen], physaddrlen);
        } else {
                memcpy ((char *)physaddr, (char *)buf, physaddrlen);
                memcpy ((char *)sap, (char *)&buf [physaddrlen], 0 - saplen);
        }
}

/*
 * Parse an interface name and extract the unit number
 */

static int dlpiunit (ifname)
        char *ifname;
{
        int fd;
        char *cp, *dp, *ep;
        int unit;
        
        if (!ifname) {
                return 0;
        }
        
        /* Advance to the end of the name */
        cp = ifname;
        while (*cp) cp++;
        /* Back up to the start of the first digit */
        while ((*(cp-1) >= '0' && *(cp-1) <= '9') || *(cp - 1) == ':') cp--;
        
        /* Convert the unit number */
        unit = 0;
        while (*cp >= '0' && *cp <= '9') {
                unit *= 10;
                unit += (*cp++ - '0');
        }
        
        return unit;
}

/*
 * dlpiopen - open the DLPI device for a given interface name
 */
static int dlpiopen (ifname)
        char *ifname;
{
        char devname [50];
        char *cp, *dp, *ep;
        
        if (!ifname) {
                return -1;
        }
        
        /* Open a DLPI device */
        if (*ifname == '/') {
                dp = devname;
        } else {
                /* Prepend the device directory */
                memcpy (devname, DLPI_DEVDIR, strlen (DLPI_DEVDIR));
                dp = &devname [strlen (DLPI_DEVDIR)];
        }

        /* Find the end of the interface name */
        ep = cp = ifname;
        while (*ep)
                ep++;
        /* And back up to the first digit (unit number) */
        while ((*(ep - 1) >= '0' && *(ep - 1) <= '9') || *(ep - 1) == ':')
                ep--;
        
        /* Copy everything up to the unit number */
        while (cp < ep) {
                *dp++ = *cp++;
        }
        *dp = '\0';
        
        return open (devname, O_RDWR, 0);
}

/*
 * dlpiinforeq - request information about the data link provider.
 */

static int dlpiinforeq (fd)
        int fd;
{
        dl_info_req_t info_req;
        struct strbuf ctl;
        int flags;
        
        info_req.dl_primitive = DL_INFO_REQ;
        
        ctl.maxlen = 0;
        ctl.len = sizeof (info_req);
        ctl.buf = (char *)&info_req;
        
        flags = RS_HIPRI;
        
        return putmsg (fd, &ctl, (struct strbuf *)NULL, flags);
}

/*
 * dlpiphysaddrreq - request the current physical address.
 */
static int dlpiphysaddrreq (fd, addrtype)
        int fd;
        unsigned long addrtype;
{
        dl_phys_addr_req_t physaddr_req;
        struct strbuf ctl;
        int flags;
        
        physaddr_req.dl_primitive = DL_PHYS_ADDR_REQ;
        physaddr_req.dl_addr_type = addrtype;
        
        ctl.maxlen = 0;
        ctl.len = sizeof (physaddr_req);
        ctl.buf = (char *)&physaddr_req;
        
        flags = RS_HIPRI;
        
        return putmsg (fd, &ctl, (struct strbuf *)NULL, flags);
}

/*
 * dlpiattachreq - send a request to attach to a specific unit.
 */
static int dlpiattachreq (fd, ppa)
        unsigned long ppa;
        int fd;
{
        dl_attach_req_t attach_req;
        struct strbuf ctl;
        int flags;
        
        attach_req.dl_primitive = DL_ATTACH_REQ;
        attach_req.dl_ppa = ppa;
        
        ctl.maxlen = 0;
        ctl.len = sizeof (attach_req);
        ctl.buf = (char *)&attach_req;
        
        flags = 0;
        
        return putmsg (fd, &ctl, (struct strbuf*)NULL, flags);
}

/*
 * dlpibindreq - send a request to bind to a specific SAP address.
 */
static int dlpibindreq (fd, sap, max_conind, service_mode, conn_mgmt, xidtest)
        unsigned long sap;
        unsigned long max_conind;
        unsigned long service_mode;
        unsigned long conn_mgmt;
        unsigned long xidtest;
        int fd;
{
        dl_bind_req_t bind_req;
        struct strbuf ctl;
        int flags;
        
        bind_req.dl_primitive = DL_BIND_REQ;
        bind_req.dl_sap = sap;
        bind_req.dl_max_conind = max_conind;
        bind_req.dl_service_mode = service_mode;
        bind_req.dl_conn_mgmt = conn_mgmt;
        bind_req.dl_xidtest_flg = xidtest;
        
        ctl.maxlen = 0;
        ctl.len = sizeof (bind_req);
        ctl.buf = (char *)&bind_req;
        
        flags = 0;
        
        return putmsg (fd, &ctl, (struct strbuf*)NULL, flags);
}

/*
 * dlpiunbindreq - send a request to unbind.
 */
static int dlpiunbindreq (fd)
        int fd;
{
        dl_unbind_req_t unbind_req;
        struct strbuf ctl;
        int flags;
        
        unbind_req.dl_primitive = DL_UNBIND_REQ;
        
        ctl.maxlen = 0;
        ctl.len = sizeof (unbind_req);
        ctl.buf = (char *)&unbind_req;
        
        flags = 0;
        
        return putmsg (fd, &ctl, (struct strbuf*)NULL, flags);
}


/*
 * dlpidetachreq - send a request to detach.
 */
static int dlpidetachreq (fd)
        int fd;
{
        dl_detach_req_t detach_req;
        struct strbuf ctl;
        int flags;
        
        detach_req.dl_primitive = DL_DETACH_REQ;
        
        ctl.maxlen = 0;
        ctl.len = sizeof (detach_req);
        ctl.buf = (char *)&detach_req;
        
        flags = 0;
        
        return putmsg (fd, &ctl, (struct strbuf*)NULL, flags);
}


/*
 * dlpibindack - receive an ack to a dlbindreq.
 */
static int dlpibindack (fd, bufp)
        char *bufp;
        int fd;
{
        union DL_primitives *dlp;
        struct strbuf ctl;
        int flags;
        
        ctl.maxlen = DLPI_MAXDLBUF;
        ctl.len = 0;
        ctl.buf = bufp;

        if (strgetmsg (fd, &ctl,
                       (struct strbuf*)NULL, &flags, "dlpibindack") < 0) {
                return -1;
        }
        
        dlp = (union DL_primitives *)ctl.buf;
        
        if (!expected (DL_BIND_ACK, dlp, flags) < 0) {
                return -1;
        }
        
        if (ctl.len < sizeof (dl_bind_ack_t)) {
                /* Returned structure is too short */
                return -1;
        }

        return 0;
}

/*
 * dlpiokack - general acknowledgement reception.
 */
static int dlpiokack (fd, bufp)
        char *bufp;
        int fd;
{
        union DL_primitives *dlp;
        struct strbuf ctl;
        int flags;
        
        ctl.maxlen = DLPI_MAXDLBUF;
        ctl.len = 0;
        ctl.buf = bufp;
        
        if (strgetmsg (fd, &ctl,
                       (struct strbuf*)NULL, &flags, "dlpiokack") < 0) {
                return -1;
        }
        
        dlp = (union DL_primitives *)ctl.buf;
        
        if (!expected (DL_OK_ACK, dlp, flags) < 0) {
                return -1;
        }
        
        if (ctl.len < sizeof (dl_ok_ack_t)) {
                /* Returned structure is too short */
                return -1;
        }
        
        return 0;
}

/*
 * dlpiinfoack - receive an ack to a dlinforeq.
 */
static int dlpiinfoack (fd, bufp)
        char *bufp;
        int fd;
{
        union DL_primitives *dlp;
        struct strbuf ctl;
        int flags;
        
        ctl.maxlen = DLPI_MAXDLBUF;
        ctl.len = 0;
        ctl.buf = bufp;
        
        if (strgetmsg (fd, &ctl, (struct strbuf *)NULL, &flags,
                       "dlpiinfoack") < 0) {
                return -1;
        }
        
        dlp = (union DL_primitives *) ctl.buf;
        
        if (!expected (DL_INFO_ACK, dlp, flags) < 0) {
                return -1;
        }
        
        if (ctl.len < sizeof (dl_info_ack_t)) {
                /* Returned structure is too short */
                return -1;
        }
        
        return 0;
}

/*
 * dlpiphysaddrack - receive an ack to a dlpiphysaddrreq.
 */
int dlpiphysaddrack (fd, bufp)
        char *bufp;
        int fd;
{
        union DL_primitives *dlp;
        struct strbuf ctl;
        int flags;
        
        ctl.maxlen = DLPI_MAXDLBUF;
        ctl.len = 0;
        ctl.buf = bufp;
        
        if (strgetmsg (fd, &ctl, (struct strbuf *)NULL, &flags,
                       "dlpiphysaddrack") < 0) {
                return -1;
        }

        dlp = (union DL_primitives *)ctl.buf;
        
        if (!expected (DL_PHYS_ADDR_ACK, dlp, flags) < 0) {
                return -1;
        }

        if (ctl.len < sizeof (dl_phys_addr_ack_t)) {
                /* Returned structure is too short */
                return -1;
        }
        
        return 0;
}

int dlpiunitdatareq (fd, addr, addrlen, minpri, maxpri, dbuf, dbuflen)
        int fd;
        unsigned char *addr;
        int addrlen;
        unsigned long minpri;
        unsigned long maxpri;
        unsigned char *dbuf;
        int dbuflen;
{
        long buf [DLPI_MAXDLBUF];
        union DL_primitives *dlp;
        struct strbuf ctl, data;
        
        /* Set up the control information... */
        dlp = (union DL_primitives *)buf;
        dlp -> unitdata_req.dl_primitive = DL_UNITDATA_REQ;
        dlp -> unitdata_req.dl_dest_addr_length = addrlen;
        dlp -> unitdata_req.dl_dest_addr_offset = sizeof (dl_unitdata_req_t);
        dlp -> unitdata_req.dl_priority.dl_min = minpri;
        dlp -> unitdata_req.dl_priority.dl_max = maxpri;

        /* Append the destination address */
        memcpy ((char *)buf + dlp -> unitdata_req.dl_dest_addr_offset,
                addr, addrlen);
        
        ctl.maxlen = 0;
        ctl.len = dlp -> unitdata_req.dl_dest_addr_offset + addrlen;
        ctl.buf = (char *)buf;

        data.maxlen = 0;
        data.buf = (char *)dbuf;
        data.len = dbuflen;

        /* Send the packet down the wire... */
        return putmsg (fd, &ctl, &data, 0);
}

static int dlpiunitdataind (fd, daddr, daddrlen,
                            saddr, saddrlen, grpaddr, dbuf, dlen)
        int fd;
        unsigned char *daddr;
        unsigned long *daddrlen;
        unsigned char *saddr;
        unsigned long *saddrlen;
        unsigned long *grpaddr;
        unsigned char *dbuf;
        int dlen;
{
        long buf [DLPI_MAXDLBUF];
        union DL_primitives *dlp;
        struct strbuf ctl, data;
        int flags = 0;
        int result;

        /* Set up the msg_buf structure... */
        dlp = (union DL_primitives *)buf;
        dlp -> unitdata_ind.dl_primitive = DL_UNITDATA_IND;

        ctl.maxlen = DLPI_MAXDLBUF;
        ctl.len = 0;
        ctl.buf = (char *)buf;
        
        data.maxlen = dlen;
        data.len = 0;
        data.buf = (char *)dbuf;
        
        result = getmsg (fd, &ctl, &data, &flags);
        
        if (result != 0) {
                return -1;
        }
        
        if (ctl.len < sizeof (dl_unitdata_ind_t) ||
            dlp -> unitdata_ind.dl_primitive != DL_UNITDATA_IND) {
                return -1;
        }
        
        if (data.len <= 0) {
                return data.len;
        }

        /* Copy sender info */
        if (saddr) {
                memcpy (saddr, &buf [dlp -> unitdata_ind.dl_src_addr_offset],
                        dlp -> unitdata_ind.dl_src_addr_length);
        }
        if (saddrlen) {
                *saddrlen = dlp -> unitdata_ind.dl_src_addr_length;
        }

        /* Copy destination info */
        if (daddr) {
                memcpy (daddr, &buf [dlp -> unitdata_ind.dl_dest_addr_offset],
                        dlp -> unitdata_ind.dl_dest_addr_length);
        }
        if (daddrlen) {
                *daddrlen = dlp -> unitdata_ind.dl_dest_addr_length;
        }
        
        if (grpaddr) {
                *grpaddr = dlp -> unitdata_ind.dl_group_address;
        }
        
        return data.len;
}

/*
 * expected - see if we got what we wanted.
 */
static int expected (prim, dlp, msgflags)
        unsigned long prim;
        union DL_primitives *dlp;
        int msgflags;
{
        if (msgflags != RS_HIPRI) {
                /* Message was not M_PCPROTO */
                return 0;
        }

        if (dlp -> dl_primitive != prim) {
                /* Incorrect/unexpected return message */
                return 0;
        }
        
        return 1;
}

/*
 * strgetmsg - get a message from a stream, with timeout.
 */
static int strgetmsg (fd, ctlp, datap, flagsp, caller)
        struct strbuf *ctlp, *datap;
        char *caller;
        int *flagsp;
        int fd;
{
        int result;
#ifdef USE_POLL
        struct pollfd pfd;
        int count;
        time_t now;
        time_t starttime;
        int to_msec;
#endif
        
#ifdef USE_POLL
        pfd.fd = fd;
        pfd.events = POLLPRI;   /* We're only interested in knowing
                                 * when we can receive the next high
                                 * priority message.
                                 */
        pfd.revents = 0;

        now = time (&starttime);
        while (now <= starttime + DLPI_MAXWAIT) {
                to_msec = ((starttime + DLPI_MAXWAIT) - now) * 1000;
                count = poll (&pfd, 1, to_msec);
                
                if (count == 0) {
                        /* log_fatal ("strgetmsg: timeout"); */
                        return -1;
                } else if (count < 0) {
                        if (errno == EAGAIN || errno == EINTR) {
                                time (&now);
                                continue;
                        } else {
                                /* log_fatal ("poll: %m"); */
                                return -1;
                        }
                } else {
                        break;
                }
        }
#else  /* defined (USE_POLL) */
        /*
         * Start timer.  Can't use select, since it might return true if there
         * were non High-Priority data available on the stream.
         */
        (void) sigset (SIGALRM, sigalrm);
        
        if (alarm (DLPI_MAXWAIT) < 0) {
                /* log_fatal ("alarm: %m"); */
                return -1;
        }
#endif /* !defined (USE_POLL) */

        /*
         * Set flags argument and issue getmsg ().
         */
        *flagsp = 0;
        if ((result = getmsg (fd, ctlp, datap, flagsp)) < 0) {
                return result;
        }

#ifndef USE_POLL
        /*
         * Stop timer.
         */     
        if (alarm (0) < 0) {
                /* log_fatal ("alarm: %m"); */
                return -1;
        }
#endif

        /*
         * Check for MOREDATA and/or MORECTL.
         */
        if (result & (MORECTL|MOREDATA)) {
                return -1;
        }

        /*
         * Check for at least sizeof (long) control data portion.
         */
        if (ctlp -> len < sizeof (long)) {
                return -1;
        }

        return 0;
}

#ifndef USE_POLL
/*
 * sigalrm - handle alarms.
 */
static void sigalrm (sig)
        int sig;
{
        fprintf (stderr, "strgetmsg: timeout");
        exit (1);
}
#endif /* !defined (USE_POLL) */

int can_unicast_without_arp (ip)
        struct interface_info *ip;
{
        return 1;
}

int can_receive_unicast_unconfigured (ip)
        struct interface_info *ip;
{
        return 1;
}

void maybe_setup_fallback ()
{
        struct interface_info *fbi;
        fbi = setup_fallback ();
        if (fbi) {
                if_register_fallback (fbi);
                add_protocol ("fallback", fallback_interface -> wfdesc,
                              fallback_discard, fallback_interface);
        }
}
#endif /* USE_DLPI */