ipaddress_ioctl.c

开发snmp的开发包有两个开放的SNMP开发库

}

/**
 * find unused alias number
 */
static int
_next_alias(const char *if_name)
{
    int             i, j, k, sd, interfaces = 0, len;
    struct ifconf   ifc;
    struct ifreq   *ifrp;
    char                    *alias;
    int                     *alias_list;

    if (NULL == if_name)
        return -1;
    len = strlen(if_name);

    if ((sd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        snmp_log(LOG_ERR, "could not create socket\n");
        return -1;
    }

    interfaces =
        netsnmp_access_ipaddress_ioctl_get_interface_count(sd, &ifc);
    if(interfaces < 0) {
        close(sd);
        return -2;
    }
    netsnmp_assert(NULL != ifc.ifc_buf);
    DEBUGMSGTL(("access:ipaddress:container", "processing %d interfaces\n", interfaces));

    alias_list = malloc(interfaces * sizeof(int));
    if (NULL == alias_list) {
        close(sd);
        return -2;
    }

    ifrp = ifc.ifc_req;
    for(i=0,j=0; i < interfaces; ++i, ++ifrp) {

        if (strncmp(ifrp->ifr_name, if_name, len) != 0)
            continue;

        DEBUGMSGTL(("access:ipaddress:container",
                    " interface %d, %s\n", i, ifrp->ifr_name));

        alias = strchr(ifrp->ifr_name, ':');
        if (NULL == alias)
            continue;

        ++alias; /* skip ':' */
        alias_list[j++] = atoi(alias);
    }

    /*
     * clean up
     */
    free(ifc.ifc_buf);
    close(sd);

    /*
     * return first unused alias
     */
    for(i=1; i<=interfaces; ++i) {
        for(k=0;k<j;++k)
            if (alias_list[k] == i)
                break;
        if (k == j)
            return i;
    }

    return interfaces + 1;
}


/**
 *
 * @retval  0 : no error
 * @retval -1 : bad parameter
 * @retval -2 : couldn't create socket
 * @retval -3 : ioctl failed
 */
int
_netsnmp_ioctl_ipaddress_set_v4(netsnmp_ipaddress_entry * entry)
{
    struct ifreq                   ifrq;
    struct sockaddr_in            *sin;
    int                            rc, fd = -1;
    _ioctl_extras                 *extras;

    if (NULL == entry)
        return -1;

    netsnmp_assert(4 == entry->ia_address_len);

    extras = netsnmp_ioctl_ipaddress_extras_get(entry);
    if (NULL == extras)
        return -1;

    fd = socket(AF_INET, SOCK_DGRAM, 0);
    if(fd < 0) {
        snmp_log(LOG_ERR,"couldn't create socket\n");
        return -2;
    }
    memset(&ifrq, 0, sizeof(ifrq));

    if ('\0' == extras->name[0]) {
        const char *name = netsnmp_access_interface_name_find(entry->if_index);
        int   alias_idx;

        if (NULL == name) {
            DEBUGMSGT(("access:ipaddress:set", "cant find name for index %d\n",
                       entry->if_index));
            close(fd);
            return -1;
        }

        /*
         * search for unused alias
         */
        alias_idx = _next_alias(name);
        snprintf(ifrq.ifr_name,sizeof(ifrq.ifr_name), "%s:%d",
                 name, alias_idx);
    }
    else
        strncpy(ifrq.ifr_name, extras->name, sizeof(ifrq.ifr_name));

    ifrq.ifr_name[ sizeof(ifrq.ifr_name)-1 ] = 0;

    sin = (struct sockaddr_in*)&ifrq.ifr_addr;
    sin->sin_family = AF_INET;
    memcpy(&sin->sin_addr.s_addr, entry->ia_address,
           entry->ia_address_len);

    rc = ioctl(fd, SIOCSIFADDR, &ifrq);
    close(fd);
    if(rc < 0) {
        snmp_log(LOG_ERR,"error setting address\n");
        return -3;
    }

    return 0;
}

/**
 *
 * @retval  0 : no error
 * @retval -1 : bad parameter
 * @retval -2 : couldn't create socket
 * @retval -3 : ioctl failed
 */
int
_netsnmp_ioctl_ipaddress_delete_v4(netsnmp_ipaddress_entry * entry)
{
    struct ifreq                   ifrq;
    int                            rc, fd = -1;
    _ioctl_extras                 *extras;

    if (NULL == entry)
        return -1;

    netsnmp_assert(4 == entry->ia_address_len);

    extras = netsnmp_ioctl_ipaddress_extras_get(entry);
    if (NULL == extras)
        return -1;

    fd = socket(AF_INET, SOCK_DGRAM, 0);
    if(fd < 0) {
        snmp_log(LOG_ERR,"couldn't create socket\n");
        return -2;
    }

    memset(&ifrq, 0, sizeof(ifrq));

    strncpy(ifrq.ifr_name, extras->name, sizeof(ifrq.ifr_name));
    ifrq.ifr_name[ sizeof(ifrq.ifr_name)-1 ] = 0;

    ifrq.ifr_flags = 0;

    rc = ioctl(fd, SIOCSIFFLAGS, &ifrq);
    close(fd);
    if(rc < 0) {
        snmp_log(LOG_ERR,"error deleting address\n");
        return -3;
    }

    return 0;
}

/**
 * get the interface count and populate the ifc_buf
 *
 * Note: the caller assumes responsbility for the ifc->ifc_buf
 *       memory, and should free() it when done.
 *
 * @retval -1 : malloc error
 */
int
netsnmp_access_ipaddress_ioctl_get_interface_count(int sd, struct ifconf * ifc)
{
    int lastlen = 0, i;
    struct ifconf ifc_tmp;

    if (NULL == ifc) {
        memset(&ifc_tmp, 0x0, sizeof(ifc_tmp));
        ifc = &ifc_tmp;
    }

    /*
     * Cope with lots of interfaces and brokenness of ioctl SIOCGIFCONF
     * on some platforms; see W. R. Stevens, ``Unix Network Programming
     * Volume I'', p.435.  
     */

    for (i = 8;; i *= 2) {
        ifc->ifc_buf = calloc(i, sizeof(struct ifreq));
        if (NULL == ifc->ifc_buf) {
            snmp_log(LOG_ERR, "could not allocate memory for %d interfaces\n",
                     i);
            return -1;
        }
        ifc->ifc_len = i * sizeof(struct ifreq);

        if (ioctl(sd, SIOCGIFCONF, (char *) ifc) < 0) {
            if (errno != EINVAL || lastlen != 0) {
                /*
                 * Something has gone genuinely wrong.  
                 */
                snmp_log(LOG_ERR, "bad rc from ioctl, errno %d", errno);
                SNMP_FREE(ifc->ifc_buf);
                break;
            }
            /*
             * Otherwise, it could just be that the buffer is too small.  
             */
        } else {
            if (ifc->ifc_len == lastlen) {
                /*
                 * The length is the same as the last time; we're done.  
                 */
                break;
            }
            lastlen = ifc->ifc_len;
        }
        free(ifc->ifc_buf); /* no SNMP_FREE, getting ready to reassign */
    }

    if (ifc == &ifc_tmp)
        free(ifc_tmp.ifc_buf);

    return ifc->ifc_len / sizeof(struct ifreq);
}

/**
 */
static void
_print_flags(short flags)
{
/** Standard interface flags. */
    struct {
       short flag;
       const char *name;
    } map[] = {
        { IFF_UP,          "interface is up"},
        { IFF_BROADCAST,   "broadcast address valid"},
        { IFF_DEBUG,       "turn on debugging"},
        { IFF_LOOPBACK,    "is a loopback net"},
        { IFF_POINTOPOINT, "interface is has p-p link"},
        { IFF_NOTRAILERS,  "avoid use of trailers"},
        { IFF_RUNNING,     "resources allocated"},
        { IFF_NOARP,       "no ARP protocol"},
        { IFF_PROMISC,     "receive all packets"},
        { IFF_ALLMULTI,    "receive all multicast packets"},
        { IFF_MASTER,      "master of a load balancer"},
        { IFF_SLAVE,       "slave of a load balancer"},
        { IFF_MULTICAST,   "Supports multicast"},
        { IFF_PORTSEL,     "can set media type"},
        { IFF_AUTOMEDIA,   "auto media select active"},
    };
    short unknown = flags;
    int i;

    for(i = 0; i < sizeof(map)/sizeof(map[0]); ++i)
        if(flags & map[i].flag) {
            DEBUGMSGT_NC(("access:ipaddress:container","  %s\n", map[i].name));
            unknown &= ~map[i].flag;
        }

    if(unknown)
        DEBUGMSGT_NC(("access:ipaddress:container","  unknown 0x%x\n", unknown));
}