ifxtable_interface.c

开发snmp的开发包有两个开放的SNMP开发库

    netsnmp_assert(NULL != rowreq_ctx);

    /*
     * check for and handle row creation/deletion
     * and update column exist flags...
     */
    if (rowreq_ctx->rowreq_flags & MFD_ROW_DELETED) {
        CONTAINER_REMOVE(ifXTable_if_ctx.container, rowreq_ctx);
    } else {
        if (rowreq_ctx->column_set_flags) {
            rowreq_ctx->column_set_flags = 0;
        }
    }

    return SNMP_ERR_NOERROR;
}                               /* _mfd_ifXTable_irreversible_commit */

/***********************************************************************
 *
 * DATA ACCESS
 *
 ***********************************************************************/
/**
 * @internal
 * initialize the container with functions or wrappers
 */
void
_ifXTable_container_init(ifXTable_interface_ctx * if_ctx)
{
    DEBUGMSGTL(("internal:ifXTable:_ifXTable_container_init", "called\n"));

    /*
     * cache init
     *
     * special case: sharing a cache
     */
    if_ctx->cache =
        netsnmp_cache_find_by_oid(ifTable_oid, ifTable_oid_size);
    if (NULL != if_ctx->cache) {
        if_ctx->container = (netsnmp_container *) if_ctx->cache->magic;
        return;
    } else {
        snmp_log(LOG_ERR, "error finding ifTable cache\n");
    }
}

/*
 * allow direct access to container.
 */
netsnmp_container *
_ifXTable_container_get(void)
{
    return ifXTable_if_ctx.container;
}

/**
 * @internal
 * shutdown the container with functions or wrappers
 */
void
_ifXTable_container_shutdown(ifXTable_interface_ctx * if_ctx)
{
    DEBUGMSGTL(("internal:ifXTable:_ifXTable_container_shutdown",
                "called\n"));

    /*
     * ifTable does this for us
     */
}                               /* _ifXTable_container_shutdown */

/***********************************************************************
 *
 * PERSISTENCE
 *
 ***********************************************************************/

static int      _ifXTable_container_save_rows(int majorID, int minorID,
                                              void *serverarg,
                                              void *clientarg);
static void     _ifXTable_container_row_restore(const char *token,
                                                char *buf);
static int      _ifXTable_container_row_save(ifXTable_rowreq_ctx *
                                             rowreq_ctx, void *type);
static char    *_ifXTable_container_col_restore(ifXTable_rowreq_ctx *
                                                rowreq_ctx, u_int col,
                                                char *buf);
static char    *_ifXTable_container_col_save(ifXTable_rowreq_ctx *
                                             rowreq_ctx, u_int col,
                                             char *buf);

static char     row_token[] = "ifXTable";

/************************************************************
 * *_init_persistence should be called from the main table
 * init routine.
 *
 * If your table depends on rows in another table,
 * you should register your callback after the other table,
 * which should ensure the rows on which you depend are saved
 * (and re-created) before the dependent rows.
 */
void
ifXTable_container_init_persistence(netsnmp_container *container)
{
    int             rc;

    register_config_handler(NULL, row_token,
                            _ifXTable_container_row_restore, NULL, NULL);
    rc = snmp_register_callback(SNMP_CALLBACK_LIBRARY,
                                SNMP_CALLBACK_STORE_DATA,
                                _ifXTable_container_save_rows, container);

    if (rc != SNMP_ERR_NOERROR)
        snmp_log(LOG_ERR, "error registering for STORE_DATA callback "
                 "in _ifXTable_container_init_persistence\n");
}

static int
_ifXTable_container_save_rows(int majorID, int minorID, void *serverarg,
                              void *clientarg)
{
    char            sep[] =
        "##############################################################";
    char            buf[] = "#\n" "# ifXTable persistent data\n" "#";
    char           *type = netsnmp_ds_get_string(NETSNMP_DS_LIBRARY_ID,
                                                 NETSNMP_DS_LIB_APPTYPE);

    read_config_store((char *) type, sep);
    read_config_store((char *) type, buf);

    /*
     * save all rows
     */
    CONTAINER_FOR_EACH((netsnmp_container *) clientarg,
                       (netsnmp_container_obj_func *)
                       _ifXTable_container_row_save, type);

    read_config_store((char *) type, sep);
    read_config_store((char *) type, "\n");

    /*
     * never fails 
     */
    return SNMPERR_SUCCESS;
}



/************************************************************
 * _ifXTable_container_row_save
 */
static int
_ifXTable_container_row_save(ifXTable_rowreq_ctx * rowreq_ctx, void *type)
{
    /*
     * Allocate space for a line with all data for a row. An
     * attempt is made to come up with a default maximum size, but
     * there is no guarantee it will be enough. It probably will be,
     * unless you are dealing with large values or you have external
     * indexes.
     *
     * 1) allocate space for each column. Comment out columns you don't
     * intend to save. You may also need to add room for any non-
     * column data you want to store. Remeber, data will be stored in
     * ASCII form, so you need to allow for that. Here are some
     * general guidelines:
     *
     *   Object ID   :  12 * len [ASCII len of max int + 1 for .]
     *   Octet String: (2 * len) + 2 [2 ASCII chars per byte + "0x"]
     *   Integers    :  12 [ASCII len for smallest negative number]
     *
     * 2) You also need to allocate space for the row index. This will
     * be stored as an OID, which means that Octet Strings need to
     * be treated a little differently. Specifically, you will need
     * (4 * len) + 4 [3 ASCII chars per byte + 1 for ., + 4 for len].
     *
     * 3) Also, remeber to add space for the identifier and seperator
     * characters (for example, each column is prefixed by the
     * column number and a semicolon. To allow for the maximum
     * column values, 12 bytes [11 for oid + 1 for ':'] per
     * column are added).
     */
        /** xxx: add storage for external index(s)! */
#define MAX_ROW_SIZE (sizeof(row_token) + 1 +  \
        ( 12 ) + /* ASN_INTEGER ifLinkUpDownTrapEnable */ \
        ( 12 ) + /* ASN_INTEGER ifPromiscuousMode */ \
        ( ( 2 * sizeof(rowreq_ctx->data.ifAlias) ) + 3 ) + /* ASN_OCTET_STR */ \
        ( IFXTABLE_MAX_COL * 12 ) + /* column num prefix + : */ \
    2 /* LINE_TERM_CHAR + \n */ )

    char            buf[MAX_ROW_SIZE], *pos = buf, *max =
        &buf[MAX_ROW_SIZE - 1];
    char           *tmp;
    int             i;

    if (ifXTable_container_should_save(rowreq_ctx) == 0) {
        return SNMP_ERR_NOERROR;
    }

    /*
     * build the line
     */
    pos += sprintf(pos, "%s ", row_token);
    pos = read_config_save_objid(pos, rowreq_ctx->oid_idx.oids,
                                 rowreq_ctx->oid_idx.len);
    if (NULL == pos) {
        snmp_log(LOG_ERR, "error saving ifXTable row "
                 "to persistent file\n");
        return SNMP_ERR_GENERR;
    }
    *pos++ = ' ';
    if (pos > max) {
        snmp_log(LOG_ERR, "error saving ifXTable row "
                 "to persistent file (too long)\n");
        return SNMP_ERR_GENERR;
    }

    /*
     * add each column
     */
    for (i = IFXTABLE_MIN_COL; i <= IFXTABLE_MAX_COL; ++i) {

        if ((0x1 << (i - 1)) & ~IFXTABLE_SETTABLE_COLS)
            continue;

        tmp = pos;
        pos = _ifXTable_container_col_save(rowreq_ctx, i, pos);
        if (NULL == pos)
            pos = tmp;
        else
            *pos++ = ' ';
        if (pos > max) {
            snmp_log(LOG_ERR, "error saving ifXTable row "
                     "to persistent file (too long)\n");
            return SNMP_ERR_GENERR;
        }
    }

    /*
     * if you have non-column data, add it here
     */


    /*
     * store the line
     */
    pos += sprintf(pos, "%c", LINE_TERM_CHAR);
    if (pos > max) {
        snmp_log(LOG_ERR, "error saving ifXTable row "
                 "to persistent file (too long)\n");
        return SNMP_ERR_GENERR;
    }
    read_config_store((char *) type, buf);

    DEBUGMSGTL(("internal:ifXTable:_ifXTable_container_row_save",
                "saving line '%s'\n", buf));

    return SNMP_ERR_NOERROR;
}

static void
_ifXTable_container_row_restore(const char *token, char *buf)
{
    ifXTable_rowreq_ctx *rowreq_ctx;
    netsnmp_container *container;
    netsnmp_index   index;
    oid             tmp_oid[MAX_ifTable_IDX_LEN];
    u_int           col = 0, found = 0;


    if (strncmp(token, row_token, sizeof(row_token)) != 0) {
        snmp_log(LOG_ERR,
                 "unknown token in _ifXTable_container_row_restore\n");
        return;
    }

    container = _ifXTable_container_get();
    if (NULL == container) {
        snmp_log(LOG_ERR, "null container in _ifXTable_restore\n");
        return;
    }

    DEBUGMSGTL(("internal:ifXTable:_ifXTable_container_row_restore",
                "parsing line '%s'\n", buf));

    /*
     * pull out index and find row. (Since we populate the cache
     * during startup, all rows should exist.)
     */
    index.oids = tmp_oid;
    index.len = OID_LENGTH(tmp_oid);
    buf = read_config_read_objid(buf, &index.oids, &index.len);
    if (NULL == buf) {
        snmp_log(LOG_ERR, "error reading row index in "
                 "_ifXTable_container_row_restore\n");
        return;
    }
    rowreq_ctx = CONTAINER_FIND(container, &index);
    if (NULL == rowreq_ctx) {
        snmp_log(LOG_ERR, "error finding row index in "
                 "_ifXTable_container_row_restore\n");
        return;
    }

    /*
     * loop through and get each column
     */
    buf = skip_white(buf);
    while ((NULL != buf) && isdigit(*buf)) {
        /*
         * extract column, skip ':'
         */
        col = (u_int) strtol(buf, &buf, 10);
        if (NULL == buf)
            break;
        if (*buf != ':') {
            buf = NULL;
            break;
        }
        ++buf;                  /* skip : */

        /*
         * parse value
         */
        DEBUGMSGTL(("_ifXTable_container_row_restore",
                    "parsing column %d\n", col));
        buf = _ifXTable_container_col_restore(rowreq_ctx, col, buf);
        ++found;
    }
    if (0 == found) {
        snmp_log(LOG_ERR, "error parsing ifXTable row; no columns found\n");
        ifTable_release_rowreq_ctx(rowreq_ctx);
        return;
    }

    /*
     * if you added any non-column data, this is where
     * you should handle it.
     */

    /*
     * if the pointer is NULL and we didn't reach the
     * end of the line, something went wrong. Log message,
     * and bail.
     */
    if ((buf == NULL) || (*buf != LINE_TERM_CHAR)) {
        snmp_log(LOG_ERR, "error parsing ifXTable row around column %d\n",
                 col);
        return;
    }

    DEBUGMSGTL(("internal:ifXTable:_ifXTable_container_row_restore",
                "inserting row\n"));
}

/************************************************************
 * _ifXTable_container_col_save
 */
static char    *
_ifXTable_container_col_save(ifXTable_rowreq_ctx * rowreq_ctx,
                             u_int col, char *buf)
{
    if ((NULL == rowreq_ctx) || (NULL == buf)) {
        snmp_log(LOG_ERR, "bad parameter in "
                 "_ifXTable_container_col_save\n");
        return NULL;
    }

    DEBUGMSGTL(("internal:ifXTable:_ifXTable_container_col_save",
                "processing column %d\n", col));

    /*
     * prefix with column number, so we don't ever depend on
     * order saved.
     */
    buf += sprintf(buf, "%u:", col);

    /*
     * save data for the column
     */
    switch (col) {

    case COLUMN_IFLINKUPDOWNTRAPENABLE:   /** INTEGER = ASN_INTEGER */
        buf +=
            sprintf(buf, "%ld", rowreq_ctx->data.ifLinkUpDownTrapEnable);
        break;

    case COLUMN_IFALIAS:   /** DisplayString = ASN_OCTET_STR */
        buf = read_config_save_octet_string(buf, rowreq_ctx->data.ifAlias,
                                            rowreq_ctx->data.ifAlias_len);
        break;

    default:
            /** We shouldn't get here */
        snmp_log(LOG_ERR, "unknown column %d in "
                 "_ifXTable_container_col_save\n", col);
        return NULL;
    }

    return buf;
}

/************************************************************
 * _ifXTable_container_col_restore
 */
static char    *
_ifXTable_container_col_restore(ifXTable_rowreq_ctx * rowreq_ctx,
                                u_int col, char *buf)
{
    size_t          len;
    if ((NULL == rowreq_ctx) || (NULL == buf)) {
        snmp_log(LOG_ERR, "bad parameter in "
                 "_ifXTable_container_col_restore\n");
        return NULL;
    }

    DEBU