usr.sbin/ifconfig/revarp.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */
/*  Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */

#include "defs.h"
#include "ifconfig.h"
#include <sys/types.h>
#include <libdlpi.h>
#include <sys/sysmacros.h>
#include <sys/time.h>
#include <deflt.h>

#define IPADDRL     sizeof (struct in_addr)
#define RARPRETRIES 5

/*
 * The following value (8) is determined to work reliably in switched 10/100MB
 * ethernet environments. Use caution if you plan on decreasing it.
 */
#define RARPTIMEOUT 8

static char defaultfile[] = "/etc/inet/rarp";
static char retries_var[] = "RARP_RETRIES=";
static int rarp_timeout = RARPTIMEOUT;
static int rarp_retries = RARPRETRIES;

static dlpi_handle_t rarp_open(const char *, size_t *, uchar_t *, uchar_t *);
static int rarp_recv(dlpi_handle_t, struct arphdr *, size_t, size_t, int64_t);

int
doifrevarp(const char *linkname, struct sockaddr_in *laddr)
{
    int         s, retval;
    struct arphdr       *req, *ans;
    struct in_addr      from;
    struct in_addr      answer;
    struct lifreq       lifr;
    int         tries_left;
    size_t          physaddrlen, ifrarplen;
    uchar_t         my_macaddr[DLPI_PHYSADDR_MAX];
    uchar_t         my_broadcast[DLPI_PHYSADDR_MAX];
    dlpi_handle_t       dh;

    if (linkname[0] == '\0') {
        (void) fprintf(stderr, "ifconfig: doifrevarp: name not set\n");
        exit(1);
    }

    if (debug)
        (void) printf("doifrevarp interface %s\n", linkname);

    if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
        Perror0_exit("socket");

    (void) strlcpy(lifr.lifr_name, linkname, sizeof (lifr.lifr_name));
    if (ioctl(s, SIOCGLIFFLAGS, (char *)&lifr) < 0) {
        (void) close(s);
        Perror0_exit("SIOCGLIFFLAGS");
    }

    /* don't try to revarp if we know it won't work */
    if ((lifr.lifr_flags & IFF_LOOPBACK) ||
        (lifr.lifr_flags & IFF_NOARP) ||
        (lifr.lifr_flags & IFF_IPMP) ||
        (lifr.lifr_flags & IFF_POINTOPOINT)) {
        (void) close(s);
        return (0);
    }

    /* open rarp interface */
    dh = rarp_open(linkname, &physaddrlen, my_macaddr, my_broadcast);
    if (dh == NULL) {
        (void) close(s);
        return (0);
    }

    /*
     * RARP looks at /etc/ethers and NIS, which only works
     * with 6 byte addresses currently.
     */
    if (physaddrlen != ETHERADDRL) {
        dlpi_close(dh);
        (void) close(s);
        return (0);
    }

    ifrarplen = sizeof (struct arphdr) + (2 * IPADDRL) + (2 * physaddrlen);

    /* look for adjustments to rarp_retries in the RARP defaults file */
    if (defopen(defaultfile) == 0) {
        char    *cp;

        if (cp = defread(retries_var)) {
            int ntries;

            ntries = atoi(cp);
            if (ntries > 0)
                rarp_retries = ntries;
        }
        (void) defopen(NULL);   /* close default file */
    }

    /* allocate request and response buffers */
    if (((req = malloc(ifrarplen)) == NULL) ||
        ((ans = malloc(ifrarplen)) == NULL)) {
        dlpi_close(dh);
        (void) close(s);
        free(req);
        return (0);
    }

    /* create rarp request */
    (void) memset(req, 0, ifrarplen);
    req->ar_hrd = htons(ARPHRD_ETHER);
    req->ar_pro = htons(ETHERTYPE_IP);
    req->ar_hln = physaddrlen;
    req->ar_pln = IPADDRL;
    req->ar_op = htons(REVARP_REQUEST);

    (void) memcpy(&req[1], my_macaddr, physaddrlen);
    (void) memcpy((uchar_t *)req + sizeof (struct arphdr) + IPADDRL +
        physaddrlen, my_macaddr, physaddrlen);

    for (tries_left = rarp_retries; tries_left > 0; --tries_left) {
        /* send the request */
        retval = dlpi_send(dh, my_broadcast, physaddrlen, req,
            ifrarplen, NULL);
        if (retval != DLPI_SUCCESS) {
            Perrdlpi("doifrevarp: cannot send rarp request",
                linkname, retval);
            break;
        }

        if (debug)
            (void) printf("rarp sent\n");

        retval = rarp_recv(dh, ans, ifrarplen, physaddrlen,
            rarp_timeout * MILLISEC);

        if (retval != DLPI_ETIMEDOUT)
            break;

        if (debug)
            (void) printf("rarp retry\n");
    }

    if (retval == DLPI_SUCCESS) {
        (void) memcpy(&answer, (uchar_t *)ans +
            sizeof (struct arphdr) + (2 * physaddrlen) + IPADDRL,
            sizeof (answer));
        (void) memcpy(&from, (uchar_t *)ans + physaddrlen +
            sizeof (struct arphdr), sizeof (from));

        if (debug) {
            (void) printf("answer: %s", inet_ntoa(answer));
            (void) printf(" [from %s]\n", inet_ntoa(from));
        }
        laddr->sin_addr = answer;
    } else if (debug) {
        Perrdlpi("doifrevarp: could not receive rarp reply",
            linkname, retval);
    }

    dlpi_close(dh);
    (void) close(s);
    free(req);
    free(ans);
    return (retval == DLPI_SUCCESS);
}

/*
 * Open the datalink provider device and bind to the REVARP type.
 * Return the resulting DLPI handle.
 */
static  dlpi_handle_t
rarp_open(const char *linkname, size_t *alen, uchar_t *myaddr, uchar_t *mybaddr)
{
    int     retval;
    char        *physaddr, *bcastaddr;
    dlpi_info_t dlinfo;
    dlpi_handle_t   dh;

    if (debug)
        (void) printf("rarp_open %s\n", linkname);

    if ((retval = dlpi_open(linkname, &dh, 0)) != DLPI_SUCCESS) {
        Perrdlpi("rarp_open: dlpi_open failed", linkname, retval);
        return (NULL);
    }

    if ((retval = dlpi_bind(dh, ETHERTYPE_REVARP, NULL)) != DLPI_SUCCESS) {
        Perrdlpi("rarp_open: dlpi_bind failed", linkname, retval);
        goto failed;
    }

    if ((retval = dlpi_info(dh, &dlinfo, 0)) != DLPI_SUCCESS) {
        Perrdlpi("rarp_open: dlpi_info failed", linkname, retval);
        goto failed;
    }

    if (dlinfo.di_bcastaddrlen == 0) {
        (void) fprintf(stderr, "ifconfig: rarp_open: %s broadcast "
            "not supported\n", linkname);
        goto failed;
    }

    /* we assume the following are equal and fill in 'alen' */
    assert(dlinfo.di_bcastaddrlen == dlinfo.di_physaddrlen);

    (void) memcpy(mybaddr, dlinfo.di_bcastaddr, dlinfo.di_bcastaddrlen);

    *alen = dlinfo.di_physaddrlen;

    (void) memcpy(myaddr, dlinfo.di_physaddr, dlinfo.di_physaddrlen);

    if (debug) {
        bcastaddr = _link_ntoa(mybaddr, NULL, dlinfo.di_bcastaddrlen,
            IFT_OTHER);

        physaddr = _link_ntoa(myaddr, NULL, dlinfo.di_physaddrlen,
            IFT_OTHER);

        if (physaddr != NULL && bcastaddr != NULL) {
            (void) printf("device %s: broadcast address %s, mac "
                "address %s\n", linkname, bcastaddr, physaddr);
        }

        free(physaddr);
        free(bcastaddr);

        (void) printf("rarp_open: addr length = %d\n",
            dlinfo.di_physaddrlen);
    }

    return (dh);

failed:
    dlpi_close(dh);
    return (NULL);
}

/*
 * Read reply for RARP request. If a reply is received within waitms,
 * validate the reply. If it is a correct RARP reply return DLPI_SUCCESS,
 * otherwise return DLPI_ETIMEDOUT. If there is an error while reading retrun
 * the error code.
 */
static int
rarp_recv(dlpi_handle_t dh, struct arphdr *ans, size_t msglen,
    size_t physaddrlen, int64_t waitms)
{
    int     retval;
    char        *cause;
    size_t      anslen = msglen;
    hrtime_t    endtime = gethrtime() + MSEC2NSEC(waitms);
    hrtime_t    currtime;

    while ((currtime = gethrtime()) < endtime) {
        waitms = NSEC2MSEC(endtime - currtime);
        retval = dlpi_recv(dh, NULL, NULL, ans, &anslen, waitms, NULL);
        if (retval == DLPI_SUCCESS) {
            cause = NULL;

            if (anslen < msglen)
                cause = "short packet";
            else if (ans->ar_hrd != htons(ARPHRD_ETHER))
                cause = "hardware type not Ethernet";
            else if (ans->ar_pro != htons(ETHERTYPE_IP))
                cause = "protocol type not IP";
            else if (ans->ar_hln != physaddrlen)
                cause = "unexpected hardware address length";
            else if (ans->ar_pln != IPADDRL)
                cause = "unexpected protocol address length";
            if (cause != NULL) {
                (void) fprintf(stderr, "RARP packet received "
                    "but discarded (%s)\n", cause);
                continue;
            }
            switch (ntohs(ans->ar_op)) {
            case REVARP_REQUEST:
                if (debug)
                    (void) printf("Got a rarp request.\n");
                break;

            case REVARP_REPLY:
                return (DLPI_SUCCESS);

            default:
                (void) fprintf(stderr, "ifconfig: unknown "
                    "RARP opcode 0x%x\n", ans->ar_op);
                break;
            }
        } else if (retval != DLPI_ETIMEDOUT) {
            Perrdlpi("doifrevarp: dlpi_recv failed",
                dlpi_linkname(dh), retval);
            return (retval);
        }
    }

    return (DLPI_ETIMEDOUT);
}

void
dlpi_print_address(const char *linkname)
{
    uint_t  physaddrlen = DLPI_PHYSADDR_MAX;
    uchar_t physaddr[DLPI_PHYSADDR_MAX];
    char    *str;
    int retv;
    dlpi_handle_t   dh;
    dlpi_info_t dlinfo;

    if (dlpi_open(linkname, &dh, 0) != DLPI_SUCCESS) {
        /* Do not report an error */
        return;
    }

    retv = dlpi_get_physaddr(dh, DL_CURR_PHYS_ADDR, physaddr, &physaddrlen);
    if (retv != DLPI_SUCCESS) {
        Perrdlpi("dlpi_get_physaddr failed", linkname, retv);
        dlpi_close(dh);
        return;
    }

    retv = dlpi_info(dh, &dlinfo, 0);
    if (retv != DLPI_SUCCESS) {
        Perrdlpi("dlpi_info failed", linkname, retv);
        dlpi_close(dh);
        return;
    }
    dlpi_close(dh);

    str = _link_ntoa(physaddr, NULL, physaddrlen, IFT_OTHER);

    if (str != NULL && physaddrlen != 0) {
        switch (dlinfo.di_mactype) {
            case DL_IB:
                (void) printf("\tipib %s \n", str);
                break;
            default:
                (void) printf("\tether %s \n", str);
                break;
        }
        free(str);
    }
}