snmp_api.c

snmp up 2

    snmp_res_lock(MT_LIBRARY_ID, MT_LIB_SESSION);
    slp->next = Sessions;
    Sessions = slp;
    snmp_res_unlock(MT_LIBRARY_ID, MT_LIB_SESSION);

    return (slp->session);
}

/*
 * extended open 
 */
netsnmp_session *
snmp_open_ex(netsnmp_session *session,
             int (*fpre_parse)	(netsnmp_session *, netsnmp_transport *,
                                void *, int),
             int (*fparse)	(netsnmp_session *, netsnmp_pdu *, u_char *,
				 size_t),
	     int (*fpost_parse)	(netsnmp_session *, netsnmp_pdu *, int),

             int (*fbuild)	(netsnmp_session *, netsnmp_pdu *, u_char *,
				 size_t *),
	     int (*frbuild)	(netsnmp_session *, netsnmp_pdu *,
				 u_char **, size_t *, size_t *),
             int (*fcheck)	(u_char *, size_t)
	     )
{
    struct session_list *slp;
    slp = (struct session_list *) snmp_sess_open(session);
    if (!slp) {
        return NULL;
    }
    slp->internal->hook_pre = fpre_parse;
    slp->internal->hook_parse = fparse;
    slp->internal->hook_post = fpost_parse;
    slp->internal->hook_build = fbuild;
    slp->internal->hook_realloc_build = frbuild;
    slp->internal->check_packet = fcheck;

    snmp_res_lock(MT_LIBRARY_ID, MT_LIB_SESSION);
    slp->next = Sessions;
    Sessions = slp;
    snmp_res_unlock(MT_LIBRARY_ID, MT_LIB_SESSION);

    return (slp->session);
}

static struct session_list *
_sess_copy(netsnmp_session * in_session)
{
    struct session_list *slp;
    struct snmp_internal_session *isp;
    netsnmp_session *session;
    struct snmp_secmod_def *sptr;
    char           *cp;
    u_char         *ucp;
    size_t          i;

    in_session->s_snmp_errno = 0;
    in_session->s_errno = 0;

    /*
     * Copy session structure and link into list 
     */
    slp = (struct session_list *) calloc(1, sizeof(struct session_list));
    if (slp == NULL) {
        in_session->s_snmp_errno = SNMPERR_MALLOC;
        return (NULL);
    }

    slp->transport = NULL;

    isp = (struct snmp_internal_session *)calloc(1, sizeof(struct snmp_internal_session));

    if (isp == NULL) {
        snmp_sess_close(slp);
        in_session->s_snmp_errno = SNMPERR_MALLOC;
        return (NULL);
    }

    slp->internal = isp;
    slp->session = (netsnmp_session *)malloc(sizeof(netsnmp_session));
    if (slp->session == NULL) {
        snmp_sess_close(slp);
        in_session->s_snmp_errno = SNMPERR_MALLOC;
        return (NULL);
    }
    memmove(slp->session, in_session, sizeof(netsnmp_session));
    session = slp->session;

    /*
     * zero out pointers so if we have to free the session we wont free mem
     * owned by in_session 
     */
    session->peername = NULL;
    session->community = NULL;
    session->contextEngineID = NULL;
    session->contextName = NULL;
    session->securityEngineID = NULL;
    session->securityName = NULL;
    session->securityAuthProto = NULL;
    session->securityPrivProto = NULL;
    /*
     * session now points to the new structure that still contains pointers to
     * data allocated elsewhere.  Some of this data is copied to space malloc'd
     * here, and the pointer replaced with the new one.
     */

    if (in_session->peername != NULL) {
        session->peername = (char *)malloc(strlen(in_session->peername) + 1);
        if (session->peername == NULL) {
            snmp_sess_close(slp);
            in_session->s_snmp_errno = SNMPERR_MALLOC;
            return (NULL);
        }
        strcpy(session->peername, in_session->peername);
    }

    /*
     * Fill in defaults if necessary 
     */
    if (in_session->community_len != SNMP_DEFAULT_COMMUNITY_LEN) {
        ucp = (u_char *) malloc(in_session->community_len);
        if (ucp != NULL)
            memmove(ucp, in_session->community, in_session->community_len);
    } else {
        if ((cp = netsnmp_ds_get_string(NETSNMP_DS_LIBRARY_ID, 
					NETSNMP_DS_LIB_COMMUNITY)) != NULL) {
            session->community_len = strlen(cp);
            ucp = (u_char *) malloc(session->community_len);
            if (ucp)
                memmove(ucp, cp, session->community_len);
        } else {
#ifdef NO_ZEROLENGTH_COMMUNITY
            session->community_len = strlen(DEFAULT_COMMUNITY);
            ucp = (u_char *) malloc(session->community_len);
            if (ucp)
                memmove(ucp, DEFAULT_COMMUNITY, session->community_len);
#else
            ucp = (u_char *) strdup("");
#endif
        }
    }

    if (ucp == NULL) {
        snmp_sess_close(slp);
        in_session->s_snmp_errno = SNMPERR_MALLOC;
        return (NULL);
    }
    session->community = ucp;   /* replace pointer with pointer to new data */

    if (session->securityLevel <= 0) {
        session->securityLevel =
            netsnmp_ds_get_int(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_SECLEVEL);
    }

    if (session->securityLevel == 0)
        session->securityLevel = SNMP_SEC_LEVEL_NOAUTH;

    if (in_session->securityAuthProtoLen > 0) {
        session->securityAuthProto =
            snmp_duplicate_objid(in_session->securityAuthProto,
                                 in_session->securityAuthProtoLen);
        if (session->securityAuthProto == NULL) {
            snmp_sess_close(slp);
            in_session->s_snmp_errno = SNMPERR_MALLOC;
            return (NULL);
        }
    } else if (get_default_authtype(&i) != NULL) {
        session->securityAuthProto =
            snmp_duplicate_objid(get_default_authtype(NULL), i);
        session->securityAuthProtoLen = i;
    }

    if (in_session->securityPrivProtoLen > 0) {
        session->securityPrivProto =
            snmp_duplicate_objid(in_session->securityPrivProto,
                                 in_session->securityPrivProtoLen);
        if (session->securityPrivProto == NULL) {
            snmp_sess_close(slp);
            in_session->s_snmp_errno = SNMPERR_MALLOC;
            return (NULL);
        }
    } else if (get_default_privtype(&i) != NULL) {
        session->securityPrivProto =
            snmp_duplicate_objid(get_default_privtype(NULL), i);
        session->securityPrivProtoLen = i;
    }

    if (in_session->securityEngineIDLen > 0) {
        ucp = (u_char *) malloc(in_session->securityEngineIDLen);
        if (ucp == NULL) {
            snmp_sess_close(slp);
            in_session->s_snmp_errno = SNMPERR_MALLOC;
            return (NULL);
        }
        memmove(ucp, in_session->securityEngineID,
                in_session->securityEngineIDLen);
        session->securityEngineID = ucp;

    }

    if (in_session->contextEngineIDLen > 0) {
        ucp = (u_char *) malloc(in_session->contextEngineIDLen);
        if (ucp == NULL) {
            snmp_sess_close(slp);
            in_session->s_snmp_errno = SNMPERR_MALLOC;
            return (NULL);
        }
        memmove(ucp, in_session->contextEngineID,
                in_session->contextEngineIDLen);
        session->contextEngineID = ucp;
    } else if (in_session->securityEngineIDLen > 0) {
        /*
         * default contextEngineID to securityEngineIDLen if defined 
         */
        ucp = (u_char *) malloc(in_session->securityEngineIDLen);
        if (ucp == NULL) {
            snmp_sess_close(slp);
            in_session->s_snmp_errno = SNMPERR_MALLOC;
            return (NULL);
        }
        memmove(ucp, in_session->securityEngineID,
                in_session->securityEngineIDLen);
        session->contextEngineID = ucp;
        session->contextEngineIDLen = in_session->securityEngineIDLen;
    }

    if (in_session->contextName) {
        session->contextName = strdup(in_session->contextName);
        if (session->contextName == NULL) {
            snmp_sess_close(slp);
            return (NULL);
        }
    } else if ((cp = netsnmp_ds_get_string(NETSNMP_DS_LIBRARY_ID, 
					   NETSNMP_DS_LIB_CONTEXT)) != NULL) {
        cp = strdup(cp);
        if (cp == NULL) {
            snmp_sess_close(slp);
            return (NULL);
        }
        session->contextName = cp;
        session->contextNameLen = strlen(cp);
    } else {
        cp = strdup(SNMP_DEFAULT_CONTEXT);
        session->contextName = cp;
        session->contextNameLen = strlen(cp);
    }

    if (in_session->securityName) {
        session->securityName = strdup(in_session->securityName);
        if (session->securityName == NULL) {
            snmp_sess_close(slp);
            return (NULL);
        }
    } else if ((cp = netsnmp_ds_get_string(NETSNMP_DS_LIBRARY_ID, 
					   NETSNMP_DS_LIB_SECNAME)) != NULL) {
        cp = strdup(cp);
        if (cp == NULL) {
            snmp_sess_close(slp);
            return (NULL);
        }
        session->securityName = cp;
        session->securityNameLen = strlen(cp);
    }

    if ((in_session->securityAuthKeyLen <= 0) &&
        ((cp = netsnmp_ds_get_string(NETSNMP_DS_LIBRARY_ID, 
				     NETSNMP_DS_LIB_AUTHPASSPHRASE)) ||
         (cp = netsnmp_ds_get_string(NETSNMP_DS_LIBRARY_ID, 
				     NETSNMP_DS_LIB_PASSPHRASE)))) {
        session->securityAuthKeyLen = USM_AUTH_KU_LEN;
        if (generate_Ku(session->securityAuthProto,
                        session->securityAuthProtoLen,
                        (u_char *) cp, strlen(cp),
                        session->securityAuthKey,
                        &session->securityAuthKeyLen) != SNMPERR_SUCCESS) {
            snmp_set_detail
                ("Error generating a key (Ku) from the supplied authentication pass phrase.");
            snmp_sess_close(slp);
            return NULL;
        }
    }

    if ((in_session->securityPrivKeyLen <= 0) &&
        ((cp = netsnmp_ds_get_string(NETSNMP_DS_LIBRARY_ID, 
				     NETSNMP_DS_LIB_PRIVPASSPHRASE)) ||
         (cp = netsnmp_ds_get_string(NETSNMP_DS_LIBRARY_ID, 
				     NETSNMP_DS_LIB_PASSPHRASE)))) {
        session->securityPrivKeyLen = USM_PRIV_KU_LEN;
        if (generate_Ku(session->securityAuthProto,
                        session->securityAuthProtoLen,
                        (u_char *) cp, strlen(cp),
                        session->securityPrivKey,
                        &session->securityPrivKeyLen) != SNMPERR_SUCCESS) {
            snmp_set_detail
                ("Error generating a key (Ku) from the supplied privacy pass phrase.");
            snmp_sess_close(slp);
            return NULL;
        }
    }

    if (session->retries == SNMP_DEFAULT_RETRIES)
        session->retries = DEFAULT_RETRIES;
    if (session->timeout == SNMP_DEFAULT_TIMEOUT)
        session->timeout = DEFAULT_TIMEOUT;
    session->sessid = snmp_get_next_sessid();

    snmp_call_callbacks(SNMP_CALLBACK_LIBRARY, SNMP_CALLBACK_SESSION_INIT,
                        session);

    if ((sptr = find_sec_mod(session->securityModel)) != NULL &&
        sptr->session_open != NULL) {
        /*
         * security module specific inialization 
         */
        (*sptr->session_open) (session);
    }

    return (slp);
}

static struct session_list *
snmp_sess_copy(netsnmp_session * pss)
{
    struct session_list *psl;
    psl = _sess_copy(pss);
    if (!psl) {
        if (!pss->s_snmp_errno) {
            pss->s_snmp_errno = SNMPERR_GENERR;
        }
        SET_SNMP_ERROR(pss->s_snmp_errno);
    }
    return psl;
}



int
snmpv3_engineID_probe(struct session_list *slp,
                      netsnmp_session * in_session)
{
    netsnmp_pdu    *pdu = NULL, *response = NULL;
    netsnmp_session *session;
    unsigned int    i;
    int             status;

    if (slp == NULL || slp->session == NULL) {
        return 0;
    }

    session = slp->session;

    /*
     * If we are opening a V3 session and we don't know engineID we must probe
     * it -- this must be done after the session is created and inserted in the
     * list so that the response can handled correctly. 
     */

    if ((session->flags & SNMP_FLAGS_DONT_PROBE) == SNMP_FLAGS_DONT_PROBE)
        return 1;

    if (session->version == SNMP_VERSION_3) {
        if (session->securityEngineIDLen == 0) {
            if (snmpv3_build_probe_pdu(&pdu) != 0) {
                DEBUGMSGTL(("snmp_api", "unable to create probe PDU\n"));
                return 0;
            }
            DEBUGMSGTL(("snmp_api", "probing for engineID...\n"));
            status = snmp_sess_synch_response(slp, pdu, &response);

            if ((response == NULL) && (status == STAT_SUCCESS)) {
                status = STAT_ERROR;
            }

            switch (status) {
            case STAT_SUCCESS:
                in_session->s_snmp_errno = SNMPERR_INVALID_MSG; /* XX?? */
                DEBUGMSGTL(("snmp_sess_open",
                            "error: expected Report as response to probe: %s (%d)\n",
                            snmp_errstring(response->errstat),
                            response->errstat));
                break;
            case STAT_ERROR:   /* this is what we expected -> Report == STAT_ERROR */
                in_session->s_snmp_errno = SNMPERR_UNKNOWN_ENG_ID;
                break;
            case STAT_TIMEOUT:
                in_session->s_snmp_errno = SNMPERR_TIMEOUT;
            default:
                DEBUGMSGTL(("snmp_sess_open",
                            "unable to connect with remote engine: %s (%d)\n",
                            snmp_api_errstring(session->s_snmp_errno),
                            session->s_snmp_errno));
                break;
            }

            if (slp->session->securityEngineIDLen == 0) {
                DEBUGMSGTL(("snmp_api",
                            "unable to determine remote engine ID\n"));
                return 0;
            }

            in_session->s_snmp_errno = SNMPERR_SUCCESS;
            if (snmp_get_do_debugging()) {
                DEBUGMSGTL(("snmp_sess_open",
                            "  probe found engineID:  "));
                for (i = 0; i < slp->session->securityEngineIDLen; i++)
                    DEBUGMSG(("snmp_sess_open", "%02x",
                              slp->session->securityEngineID[i]));
                DEBUGMSG(("snmp_sess_open", "\n"));
            }
        }

        /*
         * if boot/time supplied set it for this engineID 
         */