isc/win32/interfaceiter.c

	interfaceiter.c revision e76d4c91bfadf823f04dcca1c1c5bcc14c67671d
/*
 * Copyright (C) 1999, 2000  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id: interfaceiter.c,v 1.3 2001/07/09 21:06:09 gson Exp $ */

/*
 * Note that this code will need to be revisited to support IPv6 Interfaces.
 * For now we just iterate through IPv4 interfaces.
 */

#include <config.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <sys/types.h>

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>

#include <isc/interfaceiter.h>
#include <isc/mem.h>
#include <isc/result.h>
#include <isc/string.h>
#include <isc/types.h>
#include <isc/util.h>
#include "errno2result.h"

/* Common utility functions */

/*
 * Extract the network address part from a "struct sockaddr".
 *
 * The address family is given explicity
 * instead of using src->sa_family, because the latter does not work
 * for copying a network mask obtained by SIOCGIFNETMASK (it does
 * not have a valid address family).
 */


#define IFITER_MAGIC        0x49464954U /* IFIT. */
#define VALID_IFITER(t)     ((t) != NULL && (t)->magic == IFITER_MAGIC)

struct isc_interfaceiter {
    unsigned int        magic;      /* Magic number. */
    isc_mem_t       *mctx;
    int         socket;
    INTERFACE_INFO      IFData;     /* Current Interface Info */
    int         numIF;      /* Current Interface count */
    int         totalIF;    /* Total Number
                           of Interfaces */
    INTERFACE_INFO      *buf;       /* Buffer for WSAIoctl data. */
    unsigned int        bufsize;    /* Bytes allocated. */
    INTERFACE_INFO      *pos;       /* Current offset in IF List */
    isc_interface_t     current;    /* Current interface data. */
    isc_result_t        result;     /* Last result code. */
};


/*
 * Size of buffer for SIO_GET_INTERFACE_LIST, in number of interfaces.
 * We assume no sane system will have more than than 1K of IP addresses on
 * all of its adapters.
 */
#define IFCONF_SIZE_INITIAL   16
#define IFCONF_SIZE_INCREMENT     64
#define IFCONF_SIZE_MAX     1040

static void
get_addr(unsigned int family, isc_netaddr_t *dst, struct sockaddr *src) {
    dst->family = family;
    switch (family) {
    case AF_INET:
        memcpy(&dst->type.in,
               &((struct sockaddr_in *) src)->sin_addr,
               sizeof(struct in_addr));
        break;
    case    AF_INET6:
        memcpy(&dst->type.in6,
               &((struct sockaddr_in6 *) src)->sin6_addr,
               sizeof(struct in6_addr));
        break;
    default:
        INSIST(0);
        break;
    }
}

isc_result_t
isc_interfaceiter_create(isc_mem_t *mctx, isc_interfaceiter_t **iterp) {
    isc_interfaceiter_t *iter;
    isc_result_t result;
    int error;
    unsigned long bytesReturned = 0;

    REQUIRE(mctx != NULL);
    REQUIRE(iterp != NULL);
    REQUIRE(*iterp == NULL);

    iter = isc_mem_get(mctx, sizeof(*iter));
    if (iter == NULL)
        return (ISC_R_NOMEMORY);

    iter->mctx = mctx;
    iter->buf = NULL;

    /*
     * Create an unbound datagram socket to do the
     * SIO_GET_INTERFACE_LIST WSAIoctl on.
     */
    if ((iter->socket = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 "making interface scan socket: %s",
                 strerror(errno));
        result = ISC_R_UNEXPECTED;
        goto socket_failure;
    }

    /*
     * Get the interface configuration, allocating more memory if
     * necessary.
     */
    iter->bufsize = IFCONF_SIZE_INITIAL*sizeof(INTERFACE_INFO);

    for (;;) {
        iter->buf = isc_mem_get(mctx, iter->bufsize);
        if (iter->buf == NULL) {
            result = ISC_R_NOMEMORY;
            goto alloc_failure;
        }

        if (WSAIoctl(iter->socket, SIO_GET_INTERFACE_LIST,
                 0, 0, iter->buf, iter->bufsize,
                 &bytesReturned, 0, 0)
            == SOCKET_ERROR)
        {
            error = WSAGetLastError();
            if (error != WSAEFAULT && error != WSAENOBUFS) {
                errno = error;
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                         "get interface configuration: %s",
                         NTstrerror(error));
                result = ISC_R_UNEXPECTED;
                goto ioctl_failure;
            }
            /*
             * EINVAL.  Retry with a bigger buffer.
             */
        } else {
            /*
             * The WSAIoctl succeeded.
             * If the number of the returned bytes is the same
             * as the buffer size, we will grow it just in
             * case and retry.
             */
            if (bytesReturned > 0 &&
                (bytesReturned < iter->bufsize))
                break;
        }
        if (iter->bufsize >= IFCONF_SIZE_MAX*sizeof(INTERFACE_INFO)) {
            UNEXPECTED_ERROR(__FILE__, __LINE__,
                     "get interface configuration: "
                     "maximum buffer size exceeded");
            result = ISC_R_UNEXPECTED;
            goto ioctl_failure;
        }
        isc_mem_put(mctx, iter->buf, iter->bufsize);

        iter->bufsize += IFCONF_SIZE_INCREMENT *
            sizeof(INTERFACE_INFO);
    }

    /*
     * A newly created iterator has an undefined position
     * until isc_interfaceiter_first() is called.
     */
    iter->pos = NULL;
    iter->result = ISC_R_FAILURE;
    iter->numIF = 0;
    iter->totalIF = bytesReturned/sizeof(INTERFACE_INFO);


    iter->magic = IFITER_MAGIC;
    *iterp = iter;
    /* We don't need the socket any more, so close it */
    closesocket(iter->socket);
    return (ISC_R_SUCCESS);

 ioctl_failure:
    isc_mem_put(mctx, iter->buf, iter->bufsize);

 alloc_failure:
    (void) closesocket(iter->socket);

 socket_failure:
    isc_mem_put(mctx, iter, sizeof *iter);
    return (result);
}

/*
 * Get information about the current interface to iter->current.
 * If successful, return ISC_R_SUCCESS.
 * If the interface has an unsupported address family, or if
 * some operation on it fails, return ISC_R_IGNORE to make
 * the higher-level iterator code ignore it.
 */

static isc_result_t
internal_current(isc_interfaceiter_t *iter, int family) {
    BOOL ifNamed = FALSE;
    unsigned long flags;

    REQUIRE(VALID_IFITER(iter));
    REQUIRE(iter->numIF >= 0);

    memset(&iter->current, 0, sizeof(iter->current));
    iter->current.af = family;

    get_addr(family, &iter->current.address,
         (struct sockaddr *)&(iter->IFData.iiAddress));

    /*
     * Get interface flags.
     */

    iter->current.flags = 0;
    flags = iter->IFData.iiFlags;

    if ((flags & IFF_UP) != 0)
        iter->current.flags |= INTERFACE_F_UP;

    if ((flags & IFF_POINTTOPOINT) != 0) {
        iter->current.flags |= INTERFACE_F_POINTTOPOINT;
        sprintf(iter->current.name, "PPP Interface %d", iter->numIF);
        ifNamed = TRUE;
    }

    if ((flags & IFF_LOOPBACK) != 0) {
        iter->current.flags |= INTERFACE_F_LOOPBACK;
        sprintf(iter->current.name, "Loopback Interface %d",
            iter->numIF);
        ifNamed = TRUE;
    }

    /*
     * If the interface is point-to-point, get the destination address.
     */
    if ((iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0) {
        get_addr(family, &iter->current.dstaddress,
        (struct sockaddr *)&(iter->IFData.iiBroadcastAddress));
    }

    if (ifNamed == FALSE)
        sprintf(iter->current.name,
            "TCP/IP Interface %d", iter->numIF);

    /*
     * Get the network mask.
     */
    switch (family) {
    case AF_INET:
        get_addr(family, &iter->current.netmask,
             (struct sockaddr *)&(iter->IFData.iiNetmask));
        break;
    case AF_INET6:
        break;
    }

    return (ISC_R_SUCCESS);
}

/*
 * Step the iterator to the next interface.  Unlike
 * isc_interfaceiter_next(), this may leave the iterator
 * positioned on an interface that will ultimately
 * be ignored.  Return ISC_R_NOMORE if there are no more
 * interfaces, otherwise ISC_R_SUCCESS.
 */
static isc_result_t
internal_next(isc_interfaceiter_t *iter) {
    if (iter->numIF >= iter->totalIF)
        return (ISC_R_NOMORE);

    /*
     * The first one needs to be set up to point to the last
     * Element of the array.  Go to the end and back up
     * Microsoft's implementation is peculiar for returning
     * the list in reverse order
     */

    if (iter->numIF == 0)
        iter->pos = (INTERFACE_INFO *)(iter->buf + (iter->totalIF));

    iter->pos--;
    if (&(iter->pos) < &(iter->buf))
        return (ISC_R_NOMORE);

    memset(&(iter->IFData), 0, sizeof(INTERFACE_INFO));
    memcpy(&(iter->IFData), iter->pos, sizeof(INTERFACE_INFO));
    iter->numIF++;

    return (ISC_R_SUCCESS);
}

isc_result_t
isc_interfaceiter_current(isc_interfaceiter_t *iter,
              isc_interface_t *ifdata) {
    REQUIRE(iter->result == ISC_R_SUCCESS);
    memcpy(ifdata, &iter->current, sizeof(*ifdata));
    return (ISC_R_SUCCESS);
}

isc_result_t
isc_interfaceiter_first(isc_interfaceiter_t *iter) {
    isc_result_t result;

    REQUIRE(VALID_IFITER(iter));

    iter->numIF = 0;
    for (;;) {
        result = internal_next(iter);
        if (result != ISC_R_SUCCESS)
            break;
        result = internal_current(iter, AF_INET);
        if (result != ISC_R_IGNORE)
            break;
    }
    iter->result = result;
    return (result);
}

isc_result_t
isc_interfaceiter_next(isc_interfaceiter_t *iter) {
    isc_result_t result;

    REQUIRE(VALID_IFITER(iter));
    REQUIRE(iter->result == ISC_R_SUCCESS);

    for (;;) {
        result = internal_next(iter);
        if (result != ISC_R_SUCCESS)
            break;
        result = internal_current(iter,AF_INET);
        if (result != ISC_R_IGNORE)
            break;
    }
    iter->result = result;
    return (result);
}

void
isc_interfaceiter_destroy(isc_interfaceiter_t **iterp) {
    isc_interfaceiter_t *iter;
    REQUIRE(iterp != NULL);
    iter = *iterp;
    REQUIRE(VALID_IFITER(iter));

    isc_mem_put(iter->mctx, iter->buf, iter->bufsize);

    iter->magic = 0;
    isc_mem_put(iter->mctx, iter, sizeof *iter);
    *iterp = NULL;
}