smux.c

snmp的源代码,已经在我的ubuntu下编译通过

                    asn_parse_int(ptr, &len, &type, &reqid, sizeof(reqid));
                if ((ptr == NULL) || type != ASN_INTEGER)
                    return SNMP_ERR_GENERR;

                ptr =
                    asn_parse_int(ptr, &len, &type, &errsts,
                                  sizeof(errsts));
                if ((ptr == NULL) || type != ASN_INTEGER)
                    return SNMP_ERR_GENERR;

                if (errsts) {
                    DEBUGMSGTL(("smux",
                                "[var_smux_write] errsts returned\n"));
                    return (errsts);
                }

                ptr =
                    asn_parse_int(ptr, &len, &type, &erridx,
                                  sizeof(erridx));
                if ((ptr == NULL) || type != ASN_INTEGER)
                    return SNMP_ERR_GENERR;

                reterr = SNMP_ERR_NOERROR;
                break;
            }
        }                       /* while (1) */
        break;                  /* case Action == RESERVE1 */

    case RESERVE2:
        DEBUGMSGTL(("smux", "[var_smux_write] entering RESERVE2\n"));
        reterr = SNMP_ERR_NOERROR;
        break;                  /* case Action == RESERVE2 */

    case FREE:
    case COMMIT:
        ptr = sout;
        *(ptr++) = (u_char) SMUX_SOUT;
        *(ptr++) = (u_char) 1;
        if (action == FREE) {
            *ptr = (u_char) 1;  /* rollback */
            DEBUGMSGTL(("smux",
                        "[var_smux_write] entering FREE - sending RollBack \n"));
        } else {
            *ptr = (u_char) 0;  /* commit */
            DEBUGMSGTL(("smux",
                        "[var_smux_write] entering FREE - sending Commit \n"));
        }

        if ((send(rptr->sr_fd, sout, 3, 0)) < 0) {
            DEBUGMSGTL(("smux",
                        "[var_smux_write] send rollback/commit failed\n"));
            return SNMP_ERR_GENERR;
        }

        reterr = SNMP_ERR_NOERROR;
        break;                  /* case Action == COMMIT */

    default:
        break;
    }
    return reterr;
}


int
smux_accept(int sd)
{
    u_char          data[SMUXMAXPKTSIZE], *ptr, type;
    struct sockaddr_in in_socket;
    struct timeval  tv;
    int             fail, fd, alen;
    int             length;
    ssize_t         len;

    alen = sizeof(struct sockaddr_in);
    /*
     * this may be too high 
     */
    tv.tv_sec = 5;
    tv.tv_usec = 0;

    /*
     * connection request 
     */
    DEBUGMSGTL(("smux", "[smux_accept] Calling accept()\n"));
    errno = 0;
    if ((fd = accept(sd, (struct sockaddr *) &in_socket, &alen)) < 0) {
        snmp_log_perror("[smux_accept] accept failed");
        return -1;
    } else {
        snmp_log(LOG_INFO, "[smux_accept] accepted fd %d from %s:%d\n",
                 fd, inet_ntoa(in_socket.sin_addr),
                 ntohs(in_socket.sin_port));
        if (npeers + 1 == SMUXMAXPEERS) {
            snmp_log(LOG_ERR,
                     "[smux_accept] denied peer on fd %d, limit %d reached",
                     fd, SMUXMAXPEERS);
            close(sd);
            return -1;
        }

        /*
         * now block for an OpenPDU 
         */
        if ((length = recv(fd, (char *) data, SMUXMAXPKTSIZE, 0)) <= 0) {
            DEBUGMSGTL(("smux",
                        "[smux_accept] peer on fd %d died or timed out\n",
                        fd));
            close(fd);
            return -1;
        }
        /*
         * try to authorize him 
         */
        ptr = data;
        len = length;
        if ((ptr = asn_parse_header(ptr, &len, &type)) == NULL) {
            smux_send_close(fd, SMUXC_PACKETFORMAT);
            close(fd);
            DEBUGMSGTL(("smux", "[smux_accept] peer on %d sent bad open"));
            return -1;
        } else if (type != (u_char) SMUX_OPEN) {
            smux_send_close(fd, SMUXC_PROTOCOLERROR);
            close(fd);
            DEBUGMSGTL(("smux",
                        "[smux_accept] peer on %d did not send open: (%d)\n",
                        type));
            return -1;
        }
        ptr = smux_open_process(fd, ptr, &len, &fail);
        if (fail) {
            smux_send_close(fd, SMUXC_AUTHENTICATIONFAILURE);
            close(fd);
            DEBUGMSGTL(("smux",
                        "[smux_accept] peer on %d failed authentication\n",
                        fd));
            return -1;
        }

        /*
         * he's OK 
         */
#ifdef SO_RCVTIMEO
        if (setsockopt
            (fd, SOL_SOCKET, SO_RCVTIMEO, (void *) &tv, sizeof(tv)) < 0) {
            DEBUGMSGTL(("smux",
                        "[smux_accept] setsockopt(SO_RCVTIMEO) failed fd %d\n",
                        fd));
            snmp_log_perror("smux_accept: setsockopt SO_RCVTIMEO");
        }
#endif
        npeers++;
        DEBUGMSGTL(("smux", "[smux_accept] fd %d\n", fd));

        /*
         * Process other PDUs already read, e.g. a registerRequest. 
         */
        len = length - (ptr - data);
        if (smux_pdu_process(fd, ptr, len) < 0) {
            /*
             * Easy come, easy go.  Clean-up is already done. 
             */
            return -1;
        }
    }
    return fd;
}

int
smux_process(int fd)
{
    int             length;
    u_char          data[SMUXMAXPKTSIZE];

    length = recv(fd, (char *) data, SMUXMAXPKTSIZE, 0);
    if (length <= 0) {
        /*
         * the peer went away, close this descriptor 
         * * and delete it from the list
         */
        DEBUGMSGTL(("smux",
                    "[smux_process] peer on fd %d died or timed out\n",
                    fd));
        smux_peer_cleanup(fd);
        return -1;
    }

    return smux_pdu_process(fd, data, length);
}

static int
smux_pdu_process(int fd, u_char * data, size_t length)
{
    int             error;
    size_t          len;
    u_char         *ptr, type;

    DEBUGMSGTL(("smux", "[smux_pdu_process] Processing %d bytes\n",
                length));

    error = 0;
    ptr = data;
    while (error == 0 && ptr != NULL && ptr < data + length) {
        len = length - (ptr - data);
        ptr = asn_parse_header(ptr, &len, &type);
        DEBUGMSGTL(("smux", "[smux_pdu_process] type is %d\n",
                    (int) type));
        switch (type) {
        case SMUX_OPEN:
            smux_send_close(fd, SMUXC_PROTOCOLERROR);
            DEBUGMSGTL(("smux",
                        "[smux_pdu_process] peer on fd %d sent duplicate open?\n",
                        fd));
            smux_peer_cleanup(fd);
            error = -1;
            break;
        case SMUX_CLOSE:
            ptr = smux_close_process(fd, ptr, &len);
            smux_peer_cleanup(fd);
            error = -1;
            break;
        case SMUX_RREQ:
            ptr = smux_rreq_process(fd, ptr, &len);
            break;
        case SMUX_RRSP:
            error = -1;
            smux_send_close(fd, SMUXC_PROTOCOLERROR);
            smux_peer_cleanup(fd);
            DEBUGMSGTL(("smux",
                        "[smux_pdu_process] peer on fd %d sent RRSP!\n",
                        fd));
            break;
        case SMUX_SOUT:
            error = -1;
            smux_send_close(fd, SMUXC_PROTOCOLERROR);
            smux_peer_cleanup(fd);
            DEBUGMSGTL(("smux", "This shouldn't have happened!\n"));
            break;
        case SMUX_TRAP:
            snmp_log(LOG_INFO, "Got trap from peer on fd %d\n", fd);
            ptr = smux_trap_process(ptr, &len);
            /*
             * watch out for close on top of this...should return correct end 
             */
            /*
             * debug this... 
             */
            ptr = NULL;
            break;
        default:
            smux_send_close(fd, SMUXC_PACKETFORMAT);
            smux_peer_cleanup(fd);
            DEBUGMSGTL(("smux", "[smux_pdu_process] Wrong type %d\n",
                        (int) type));
            error = -1;
            break;
        }
    }
    return error;
}

static u_char  *
smux_open_process(int fd, u_char * ptr, size_t * len, int *fail)
{
    u_char          type;
    long            version;
    oid             oid_name[MAX_OID_LEN];
    char            passwd[SMUXMAXSTRLEN];
    char            descr[SMUXMAXSTRLEN];
    char            oid_print[SMUXMAXSTRLEN];
    int             i;
    size_t          oid_name_len, string_len;

    if (!(ptr = asn_parse_int(ptr, len, &type, &version, sizeof(version)))) {
        DEBUGMSGTL(("smux", "[smux_open_process] version parse failed\n"));
        *fail = TRUE;
        return ((ptr += *len));
    }
    DEBUGMSGTL(("smux",
                "[smux_open_process] version %d, len %d, type %d\n",
                version, *len, (int) type));

    oid_name_len = MAX_OID_LEN;
    if ((ptr = asn_parse_objid(ptr, len, &type, oid_name,
                               &oid_name_len)) == NULL) {
        DEBUGMSGTL(("smux", "[smux_open_process] oid parse failed\n"));
        *fail = TRUE;
        return ((ptr += *len));
    }
    snprint_objid(oid_print, sizeof(oid_print), oid_name, oid_name_len);

    if (snmp_get_do_debugging()) {
        DEBUGMSGTL(("smux", "[smux_open_process] smux peer: %s\n",
                    oid_print));
        DEBUGMSGTL(("smux", "[smux_open_process] len %d, type %d\n", *len,
                    (int) type));
    }

    string_len = SMUXMAXSTRLEN;
    if ((ptr = asn_parse_string(ptr, len, &type, (u_char *) descr,
                                &string_len)) == NULL) {
        DEBUGMSGTL(("smux", "[smux_open_process] descr parse failed\n"));
        *fail = TRUE;
        return ((ptr += *len));
    }

    if (snmp_get_do_debugging()) {
        DEBUGMSGTL(("smux", "[smux_open_process] smux peer descr: "));
        for (i = 0; i < (int) string_len; i++)
            DEBUGMSG(("smux", "%c", descr[i]));
        DEBUGMSG(("smux", "\n"));
        DEBUGMSGTL(("smux", "[smux_open_process] len %d, type %d\n", *len,
                    (int) type));
    }
    descr[string_len] = 0;

    string_len = SMUXMAXSTRLEN;
    if ((ptr = asn_parse_string(ptr, len, &type, (u_char *) passwd,
                                &string_len)) == NULL) {
        DEBUGMSGTL(("smux", "[smux_open_process] passwd parse failed\n"));
        *fail = TRUE;
        return ((ptr += *len));
    }

    if (snmp_get_do_debugging()) {
        DEBUGMSGTL(("smux", "[smux_open_process] smux peer passwd: "));
        for (i = 0; i < (int) string_len; i++)
            DEBUGMSG(("smux", "%c", passwd[i]));
        DEBUGMSG(("smux", "\n"));
        DEBUGMSGTL(("smux", "[smux_open_process] len %d, type %d\n", *len,
                    (int) type));
    }
    passwd[string_len] = '\0';
    if (!smux_auth_peer(oid_name, oid_name_len, passwd, fd)) {
        snmp_log(LOG_WARNING,
                 "refused smux peer: oid %s, descr %s\n",
                 oid_print, descr);
        *fail = TRUE;
        return ptr;
    }
    snmp_log(LOG_INFO,
             "accepted smux peer: oid %s, descr %s\n",
             oid_print, descr);
    *fail = FALSE;
    return ptr;
}

static void
smux_send_close(int fd, int reason)
{
    u_char          outpacket[3], *ptr;

    ptr = outpacket;

    *(ptr++) = (u_char) SMUX_CLOSE;
    *(ptr++) = (u_char) 1;
    *ptr = (u_char) (reason & 0xFF);

    if (snmp_get_do_debugging())
        DEBUGMSGTL(("smux",
                    "[smux_close] sending close to fd %d, reason %d\n", fd,
                    reason));

    /*
     * send a response back 
     */
    if (send(fd, (char *) outpacket, 3, 0) < 0) {
        snmp_log_perror("[smux_snmp_close] send failed");
    }
}


static int
smux_auth_peer(oid * name, size_t namelen, char *passwd, int fd)
{
    int             i;

    for (i = 0; i < nauths; i++) {
        if (snmp_oid_compare(Auths[i]->sa_oid, Auths[i]->sa_oid_len,
                             name, namelen) == 0) {
            if (!(strcmp(Auths[i]->sa_passwd, passwd)) &&
                (Auths[i]->sa_active_fd == -1)) {
                /*
                 * matched, mark the auth 
                 */
                Auths[i]->sa_active_fd = fd;
                return 1;
            }
        }
    }
    /*
     * did not match oid and passwd 
     */
    return 0;
}


/*
 * XXX - Bells and Whistles:
 * Need to catch signal when snmpd goes down and send close pdu to gated 
 */
static u_char  *
smux_close_process(int fd, u_char * ptr, size_t * len)
{
    long            down = 0;
    int             length = *len;

    /*
     * This is the integer part of the close pdu 
     */
    while (length--) {
        down = (down << 8) | (long) *ptr;
        ptr++;
    }

    DEBUGMSGTL(("smux",
                "[smux_close_process] close from peer on fd %d reason %d\n",
                fd, down));
    smux_peer_cleanup(fd);

    return NULL;
}

static u_char  *
smux_rreq_process(int sd, u_char * ptr, size_t * len)
{
    long            priority, rpriority;
    long            operation;
    oid             oid_name[MAX_OID_LEN];
    size_t          oid_name_len;
    int             i, result;
    u_char          type;
    smux_reg       *rptr, *nrptr;

    oid_name_len = MAX_OID_LEN;
    ptr = asn_parse_objid(ptr, len, &type, oid_name, &oid_name_len);

    DEBUGMSGTL(("smux", "[smux_rreq_process] smux subtree: "));
    DEBUGMSGOID(("smux", oid_name, oid_name_len));
    DEBUGMSG(("smux", "\n"));

    if ((ptr = asn_parse_int(ptr, len, &type, &priority,
                             sizeof(priority))) == NULL) {
        DEBUGMSGTL(("smux",
                    "[smux_rreq_process] priority parse failed\n"));
        smux_send_rrsp(sd, -1);
        return NULL;
    }
    DEBUGMSGTL(("smux", "[smux_rreq_process] priority %d\n", priority));

    if ((ptr = asn_parse_int(ptr, len, &type, &operation,
                             sizeof(operation))) == NULL) {
        DEBUGMSGTL(("smux",
                    "[smux_rreq_process] operation parse failed\n"));
        smux_send_rrsp(sd, -1);
        return NULL;
    }
    DEBUGMSGTL(("smux", "[smux_rreq_process] operation %d\n", operation));

    if (operation == SMUX_REGOP_DELETE) {
        /*
         * search the active list for this registration 
         */
        rptr =
            smux_find_match(ActiveRegs, sd, oid_name, oid_name_len,
                            priority);
        if (rptr) {
            rpriority = rptr->sr_priority;
            /*
             * unregister the mib 
             */
            unregister_mib(rptr->sr_name, rptr->sr_name_len);
            /*
             * find a replacement 
             */
            nrptr =
                smux_find_replacement(rptr->sr_name, rptr->sr_name_len);
            if (nrptr) {
                /*
                 * found one 
                 */
                smux_replace_active(rptr, nrptr);
            } else {
                /*
                 * no replacement found 
                 */