header_complex.c

snmp的源代码,已经在我的ubuntu下编译通过

/*
 * header complex:  More complex storage and data sorting for mib modules 
 */

#include <net-snmp/net-snmp-config.h>

#include <sys/types.h>
#if HAVE_WINSOCK_H
#include <winsock.h>
#endif
#if HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif

#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>
#include "header_complex.h"

int
header_complex_generate_varoid(netsnmp_variable_list * var)
{
    int             i;

    if (var->name == NULL) {
        /*
         * assume cached value is correct 
         */
        switch (var->type) {
        case ASN_INTEGER:
        case ASN_COUNTER:
        case ASN_GAUGE:
        case ASN_TIMETICKS:
            var->name_length = 1;
            var->name = (oid *) malloc(sizeof(oid));
            if (var->name == NULL)
                return SNMPERR_GENERR;
            var->name[0] = *(var->val.integer);
            break;

        case ASN_PRIV_IMPLIED_OBJECT_ID:
            var->name_length = var->val_len / sizeof(oid);
            var->name = (oid *) malloc(sizeof(oid) * (var->name_length));
            if (var->name == NULL)
                return SNMPERR_GENERR;

            for (i = 0; i < (int) var->name_length; i++)
                var->name[i] = var->val.objid[i];
            break;

        case ASN_OBJECT_ID:
            var->name_length = var->val_len / sizeof(oid) + 1;
            var->name = (oid *) malloc(sizeof(oid) * (var->name_length));
            if (var->name == NULL)
                return SNMPERR_GENERR;

            var->name[0] = var->name_length - 1;
            for (i = 0; i < (int) var->name_length - 1; i++)
                var->name[i + 1] = var->val.objid[i];
            break;

        case ASN_PRIV_IMPLIED_OCTET_STR:
            var->name_length = var->val_len;
            var->name = (oid *) malloc(sizeof(oid) * (var->name_length));
            if (var->name == NULL)
                return SNMPERR_GENERR;

            for (i = 0; i < (int) var->val_len; i++)
                var->name[i] = (oid) var->val.string[i];
            break;

        case ASN_OPAQUE:
        case ASN_OCTET_STR:
            var->name_length = var->val_len + 1;
            var->name = (oid *) malloc(sizeof(oid) * (var->name_length));
            if (var->name == NULL)
                return SNMPERR_GENERR;

            var->name[0] = (oid) var->val_len;
            for (i = 0; i < (int) var->val_len; i++)
                var->name[i + 1] = (oid) var->val.string[i];
            break;

        default:
            DEBUGMSGTL(("header_complex_generate_varoid",
                        "invalid asn type: %d\n", var->type));
            return SNMPERR_GENERR;
        }
    }
    if (var->name_length > MAX_OID_LEN) {
        DEBUGMSGTL(("header_complex_generate_varoid",
                    "Something terribly wrong, namelen = %d\n",
                    var->name_length));
        return SNMPERR_GENERR;
    }

    return SNMPERR_SUCCESS;
}

/*
 * header_complex_parse_oid(): parses an index to the usmTable to
 * break it down into a engineID component and a name component.
 * The results are stored in the data pointer, as a varbindlist:
 * 
 * 
 * returns 1 if an error is encountered, or 0 if successful.
 */
int
header_complex_parse_oid(oid * oidIndex, size_t oidLen,
                         netsnmp_variable_list * data)
{
    netsnmp_variable_list *var = data;
    int             i, itmp;

    while (var && oidLen > 0) {
        switch (var->type) {
        case ASN_INTEGER:
        case ASN_COUNTER:
        case ASN_GAUGE:
        case ASN_TIMETICKS:
            var->val.integer = (long *) calloc(1, sizeof(long));
            if (var->val.string == NULL)
                return SNMPERR_GENERR;

            *var->val.integer = (long) *oidIndex++;
            var->val_len = sizeof(long);
            oidLen--;
            DEBUGMSGTL(("header_complex_parse_oid",
                        "Parsed int(%d): %d\n", var->type,
                        *var->val.integer));
            break;

        case ASN_OBJECT_ID:
        case ASN_PRIV_IMPLIED_OBJECT_ID:
            if (var->type == ASN_PRIV_IMPLIED_OBJECT_ID) {
                itmp = oidLen;
            } else {
                itmp = (long) *oidIndex++;
                oidLen--;
                if (itmp > (int) oidLen)
                    return SNMPERR_GENERR;
            }

            if (itmp == 0)
                break;          /* zero length strings shouldn't malloc */

            var->val_len = itmp * sizeof(oid);
            var->val.objid = (oid *) calloc(1, var->val_len);
            if (var->val.objid == NULL)
                return SNMPERR_GENERR;

            for (i = 0; i < itmp; i++)
                var->val.objid[i] = (u_char) * oidIndex++;
            oidLen -= itmp;

            DEBUGMSGTL(("header_complex_parse_oid", "Parsed oid: "));
            DEBUGMSGOID(("header_complex_parse_oid", var->val.objid,
                         var->val_len / sizeof(oid)));
            DEBUGMSG(("header_complex_parse_oid", "\n"));
            break;

        case ASN_OPAQUE:
        case ASN_OCTET_STR:
        case ASN_PRIV_IMPLIED_OCTET_STR:
            if (var->type == ASN_PRIV_IMPLIED_OCTET_STR) {
                itmp = oidLen;
            } else {
                itmp = (long) *oidIndex++;
                oidLen--;
                if (itmp > (int) oidLen)
                    return SNMPERR_GENERR;
            }

            if (itmp == 0)
                break;          /* zero length strings shouldn't malloc */

            /*
             * malloc by size+1 to allow a null to be appended. 
             */
            var->val_len = itmp;
            var->val.string = (u_char *) calloc(1, itmp + 1);
            if (var->val.string == NULL)
                return SNMPERR_GENERR;

            for (i = 0; i < itmp; i++)
                var->val.string[i] = (u_char) * oidIndex++;
            var->val.string[itmp] = '\0';
            oidLen -= itmp;

            DEBUGMSGTL(("header_complex_parse_oid",
                        "Parsed str(%d): %s\n", var->type,
                        var->val.string));
            break;

        default:
            DEBUGMSGTL(("header_complex_parse_oid",
                        "invalid asn type: %d\n", var->type));
            return SNMPERR_GENERR;
        }
        var = var->next_variable;
    }
    if (var != NULL || oidLen > 0)
        return SNMPERR_GENERR;
    return SNMPERR_SUCCESS;
}


void
header_complex_generate_oid(oid * name, /* out */
                            size_t * length,    /* out */
                            oid * prefix,
                            size_t prefix_len,
                            netsnmp_variable_list * data)
{

    oid            *oidptr;
    netsnmp_variable_list *var;

    if (prefix) {
        memcpy(name, prefix, prefix_len * sizeof(oid));
        oidptr = (name + (prefix_len));
        *length = prefix_len;
    } else {
        oidptr = name;
        *length = 0;
    }

    for (var = data; var != NULL; var = var->next_variable) {
        header_complex_generate_varoid(var);
        memcpy(oidptr, var->name, sizeof(oid) * var->name_length);
        oidptr = oidptr + var->name_length;
        *length += var->name_length;
    }

    DEBUGMSGTL(("header_complex_generate_oid", "generated: "));
    DEBUGMSGOID(("header_complex_generate_oid", name, *length));
    DEBUGMSG(("header_complex_generate_oid", "\n"));
}

/*
 * finds the data in "datalist" stored at "index" 
 */
void           *
header_complex_get(struct header_complex_index *datalist,
                   netsnmp_variable_list * index)
{
    oid             searchfor[MAX_OID_LEN];
    size_t          searchfor_len;

    header_complex_generate_oid(searchfor,      /* out */
                                &searchfor_len, /* out */
                                NULL, 0, index);
    return header_complex_get_from_oid(datalist, searchfor, searchfor_len);
}

void           *
header_complex_get_from_oid(struct header_complex_index *datalist,
                            oid * searchfor, size_t searchfor_len)
{
    struct header_complex_index *nptr;
    for (nptr = datalist; nptr != NULL; nptr = nptr->next) {
        if (netsnmp_oid_equals(searchfor, searchfor_len,
                             nptr->name, nptr->namelen) == 0)
            return nptr->data;
    }
    return NULL;
}


void           *
header_complex(struct header_complex_index *datalist,
               struct variable *vp,
               oid * name,
               size_t * length,
               int exact, size_t * var_len, WriteMethod ** write_method)
{

    struct header_complex_index *nptr, *found = NULL;
    oid             indexOid[MAX_OID_LEN];
    size_t          len;
    int             result;

    /*
     * set up some nice defaults for the user 
     */
    if (write_method)
        *write_method = NULL;
    if (var_len)