protocol.c

非常不错的网管开发包

DEBUGMSGTL(("agentx","padding %.2x %.2x)\n", *(bufp+2), *(bufp+3)));
     bufp    += 4;
     *length -= 4;
     
DEBUGMSGTL(("agentx","\t "));
     bufp = agentx_dump_oid( bufp, length, network_byte_order );
     if ( bufp == NULL )
	    return NULL;

DEBUGMSGTL(("agentx","\t value = "));
     switch ( type ) {
	case ASN_INTEGER:
	case ASN_COUNTER:
	case ASN_GAUGE:
	case ASN_TIMETICKS:

		agentx_dump_int( bufp, network_byte_order );
		bufp    += 4;
		*length -= 4;
		break;
		
	case ASN_OCTET_STR:
	case ASN_IPADDRESS:
	case ASN_OPAQUE:

		bufp = agentx_dump_string( bufp, length, network_byte_order );
		break;
		
	case ASN_OBJECT_ID:
		bufp = agentx_dump_oid( bufp, length, network_byte_order );
		break;
		
	case ASN_COUNTER64:
		if ( network_byte_order ) {
		    DEBUGMSGTL(("agentx","\t High "));
		    agentx_dump_int( bufp,   network_byte_order );
		    DEBUGMSGTL(("agentx","\t Low "));
		    agentx_dump_int( bufp+4, network_byte_order );
		}
		else {
		    DEBUGMSGTL(("agentx","\t Low "));
		    agentx_dump_int( bufp,   network_byte_order );
		    DEBUGMSGTL(("agentx","\t High "));
		    agentx_dump_int( bufp+4, network_byte_order );
		}
		bufp    += 8;
		*length -= 8;
		break;
		
	case ASN_NULL:
	case SNMP_NOSUCHOBJECT:
	case SNMP_NOSUCHINSTANCE:
	case SNMP_ENDOFMIBVIEW:
		/* No data associated with these types */
DEBUGMSGTL(("agentx","null data \n"));
		break;
	default:
DEBUGMSGTL(("agentx","unrecognised \n"));
		return NULL;
     }
     return bufp;
}


u_char *
agentx_dump_header(struct snmp_pdu *pdu, u_char *data, size_t *length)
{
     register u_char *bufp = data;
     size_t payload;

     if ( *length < 20 ) {	/* Incomplete header */
	return NULL;
     }

DEBUGMSGTL(("agentx","HEADER version = %d, command = %d, flags = %.2x, (reserved %d)\n", *bufp, *(bufp+1), *(bufp+2), *(bufp+3)));
     pdu->version = AGENTX_VERSION_BASE | *bufp;
     bufp++;
     pdu->command = *bufp;
     bufp++;
     pdu->flags |= *bufp;
     bufp++;
     bufp++;

DEBUGMSGTL(("agentx","\t Session ID = "));
     agentx_dump_int( bufp, pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
     bufp += 4;
DEBUGMSGTL(("agentx","\t Request ID = "));
     agentx_dump_int( bufp, pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
     bufp += 4;
DEBUGMSGTL(("agentx","\t Message ID = "));
     agentx_dump_int( bufp, pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
     bufp += 4;
DEBUGMSGTL(("agentx","\t Payload Length = "));
     payload = agentx_dump_int( bufp,
				pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
     bufp += 4;

     *length -= 20;
     if ( *length != payload ) {	/* Short payload */
	return NULL;
     }
     return bufp;
}


int
agentx_dump(struct snmp_session *session, struct snmp_pdu *pdu, u_char *data, size_t len)
{
     register u_char *bufp = data;
     u_char buffer[BUFSIZ];
     u_char *prefix_ptr;

     int    range_subid;
     int    inc;	/* Inclusive SearchRange flag */
     int    type;	/* VarBind data type */
     size_t *length = &len;

     if (!IS_AGENTX_VERSION( session->version ))
	return SNMPERR_BAD_VERSION;

		/*
		 *  Handle (common) header ....
		 */
     bufp = agentx_dump_header( pdu, bufp, length );
     if ( bufp == NULL )
	return SNMPERR_INCOMPLETE_PACKET;	/* i.e. wait for the rest */

		/*
		 *  ... and (not-un-common) context
		 */
     if ( pdu->flags & 	AGENTX_MSG_FLAG_NON_DEFAULT_CONTEXT ) {
DEBUGMSGTL(("agentx","CONTEXT "));
	bufp = agentx_dump_string( bufp, length,
				pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER );
	if ( bufp == NULL )
	    return SNMPERR_ASN_PARSE_ERR;

     }

     switch ( pdu->command ) {
	case AGENTX_MSG_OPEN:
DEBUGMSGTL(("agentx","OPEN T/Out = %d, (reserved %d %d %d)\n", *bufp, *(bufp+1), *(bufp+2), *(bufp+3)));
		bufp     += 4;
		*length  -= 4;

		bufp = agentx_dump_oid( bufp, length,
				pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER );
		if ( bufp == NULL )
		    return SNMPERR_ASN_PARSE_ERR;
		bufp = agentx_dump_string( bufp, length,
				pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER );
		if ( bufp == NULL )
		    return SNMPERR_ASN_PARSE_ERR;
		break;

	case AGENTX_MSG_CLOSE:
DEBUGMSGTL(("agentx","CLOSE reason = %d, (reserved %d %d %d)\n", *bufp, *(bufp+1), *(bufp+2), *(bufp+3)));
		bufp     += 4;
		*length  -= 4;
		break;

	case AGENTX_MSG_REGISTER:
	case AGENTX_MSG_UNREGISTER:
DEBUGMSGTL(("agentx","(Un)REGISTER T/Out = %d, priority = %d, range = %d, (reserved %d)\n", *bufp, *(bufp+1), *(bufp+2), *(bufp+3)));
		range_subid = *(bufp+2);
		bufp     += 4;
		*length -= 4;

		prefix_ptr = bufp+1;
		bufp = agentx_dump_oid( bufp, length,
				pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER );
		if ( bufp == NULL )
		    return SNMPERR_ASN_PARSE_ERR;

		if ( range_subid ) {
DEBUGMSGTL(("agentx","\t range bound = "));
    			agentx_dump_int( bufp,
				pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
			bufp    += 4;
			*length -= 4;

		}
		break;

	case AGENTX_MSG_GETBULK:
DEBUGMSGTL(("agentx","GETBULK non-rep = "));
		agentx_dump_short( bufp,
				pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
DEBUGMSGTL(("agentx","\t max-rep = "));
		agentx_dump_short( bufp+2,
				pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
		bufp    += 4;
		*length -= 4;
		/*  Fallthrough - SearchRange handling is the same */
		
	case AGENTX_MSG_GET:
	case AGENTX_MSG_GETNEXT:

			/*
			*  SearchRange List
			*  Keep going while we have data left
			*/
		while ( *length > 0 ) {
DEBUGMSGTL(("agentx","Search List \n"));
		    bufp = agentx_dump_oid( bufp, length,
				pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
		    if ( bufp == NULL )
			    return SNMPERR_ASN_PARSE_ERR;
		    bufp = agentx_dump_oid( bufp, length,
				pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
		    if ( bufp == NULL )
			    return SNMPERR_ASN_PARSE_ERR;

		}
		break;


	case AGENTX_MSG_RESPONSE:

					/* sysUpTime */
DEBUGMSGTL(("agentx","RESPONSE T/Out = "));
		agentx_dump_int( bufp,
				pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
		bufp    += 4;
		*length -= 4;
		
DEBUGMSGTL(("agentx","\t Error status = "));
		pdu->errstat   = agentx_dump_short( bufp,
				pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
DEBUGMSGTL(("agentx","\t Error index = "));
		pdu->errindex  = agentx_dump_short( bufp+2,
				pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
		bufp    += 4;
		*length -= 4;
		/*  Fallthrough - VarBind handling is the same */
		
	case AGENTX_MSG_INDEX_ALLOCATE:
	case AGENTX_MSG_INDEX_DEALLOCATE:
	case AGENTX_MSG_NOTIFY:
	case AGENTX_MSG_TESTSET:
	
			/*
			*  VarBind List
			*  Keep going while we have data left
			*/
		while ( *length > 0 ) {
		    bufp = agentx_dump_varbind( bufp, length,
				pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
		    if ( bufp == NULL )
			    return SNMPERR_ASN_PARSE_ERR;
		}
		break;

	case AGENTX_MSG_COMMITSET:
	case AGENTX_MSG_UNDOSET:
	case AGENTX_MSG_CLEANUPSET:
	case AGENTX_MSG_PING:

DEBUGMSGTL(("agentx","Empty packet\n"));
		/* "Empty" packet */
		break;


	case AGENTX_MSG_ADD_AGENT_CAPS:
DEBUGMSGTL(("agentx","ADD AGENT CAPS \n"));
		bufp = agentx_dump_oid( bufp, length,
				pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER );
		if ( bufp == NULL )
		    return SNMPERR_ASN_PARSE_ERR;
		bufp = agentx_dump_string( bufp, length,
				pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER );
		if ( bufp == NULL )
		    return SNMPERR_ASN_PARSE_ERR;
		break;

	case AGENTX_MSG_REMOVE_AGENT_CAPS:
DEBUGMSGTL(("agentx","REMOVE AGENT CAPS \n"));
		bufp = agentx_dump_oid( bufp, length,
				pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER );
		if ( bufp == NULL )
		    return SNMPERR_ASN_PARSE_ERR;
		break;

	default:
		DEBUGMSGTL(("agentx","Unrecognised PDU type"));
		return SNMPERR_UNKNOWN_PDU;
     }
     return SNMP_ERR_NOERROR;
}


#ifdef TESTING

testit( struct snmp_pdu *pdu1)
{
     char packet1[BUFSIZ];
     char packet2[BUFSIZ];
     int len1, len2;
     struct snmp_pdu pdu2;
     struct snmp_session sess;

     memset( &pdu2, 0, sizeof(struct snmp_pdu));
     memset( packet1, 0, BUFSIZ );
     memset( packet2, 0, BUFSIZ );
     
     	/* Encode this into a "packet" */
     len1 = BUFSIZ;
     if ( agentx_build( &sess, pdu1, packet1, &len1 ) < 0 ) {
         DEBUGMSGTL(("agentx","First build failed"));
	 exit(1);
     }

     DEBUGMSGTL(("agentx","First build succeeded:\n"));
     xdump( packet1, len1, "Ax1> ");
     
     	/* Unpack this into a PDU */
     len2 = len1;
     if ( agentx_parse( &pdu2, packet1, &len2, (u_char **)NULL ) < 0 ) {
         DEBUGMSGTL(("agentx","First parse failed\n"));
	 exit(1);
     }
     DEBUGMSGTL(("agentx","First parse succeeded:\n"));
     if ( len2 != 0 ) 
         DEBUGMSGTL(("agentx","Warning - parsed packet has %d bytes left\n", len2));

     	/* Encode this into another "packet" */
     len2 = BUFSIZ;
     if ( agentx_build( &sess, &pdu2, packet2, &len2 ) < 0 ) {
         DEBUGMSGTL(("agentx","Second build failed\n"));
	 exit(1);
     }

     DEBUGMSGTL(("agentx","Second build succeeded:\n"));
     xdump( packet2, len2, "Ax2> ");

	/* Compare the results */
     if ( len1 != len2 ) {
     	DEBUGMSGTL(("agentx","Error: first build (%d) is different to second (%d)\n",
			len1, len2));
	exit(1);
     }
     if (memcmp( packet1, packet2, len1 ) != 0 ) {
     	DEBUGMSGTL(("agentx","Error: first build data is different to second\n"));
	exit(1);
     }

     DEBUGMSGTL(("agentx","OK\n"));
}



main ()
{
     struct snmp_pdu pdu1;
     oid oid_buf[] = { 1, 3, 6, 1, 2, 1, 10 };
     oid oid_buf2[] = { 1, 3, 6, 1, 2, 1, 20 };
     oid null_oid[] = { 0, 0 };
     char *string = "Example string";     
     char *context = "LUCS";     

     
	/* Create an example AgentX pdu structure */

     memset( &pdu1, 0, sizeof(struct snmp_pdu));
     pdu1.command = AGENTX_MSG_TESTSET;
     pdu1.flags  =  0;
     pdu1.sessid = 16;
     pdu1.transid  = 24;
     pdu1.reqid  = 132;
     
     pdu1.time   = 10;
     pdu1.non_repeaters   = 3;
     pdu1.max_repetitions   = 32;
     pdu1.priority = 5;
     pdu1.range_subid = 0;

     snmp_pdu_add_variable( &pdu1, oid_buf, sizeof(oid_buf)/sizeof(oid),
				ASN_OBJECT_ID, (char *)oid_buf2, sizeof(oid_buf2));
     snmp_pdu_add_variable( &pdu1, oid_buf, sizeof(oid_buf)/sizeof(oid),
				ASN_INTEGER, (char *)&pdu1.reqid, sizeof(pdu1.reqid));
     snmp_pdu_add_variable( &pdu1, oid_buf, sizeof(oid_buf)/sizeof(oid),
				ASN_OCTET_STR, (char *)string, strlen(string));

     printf("Test with non-network order.....\n");
     testit( &pdu1 );

     printf("\nTest with network order.....\n");
     pdu1.flags |= AGENTX_FLAGS_NETWORK_BYTE_ORDER;
     testit( &pdu1 );

     pdu1.community = context;
     pdu1.community_len = strlen(context);
     pdu1.flags |= AGENTX_FLAGS_NON_DEFAULT_CONTEXT;
     printf("Test with non-default context.....\n");
     testit( &pdu1 );

 
}
#endif

/* returns the proper length of an incoming agentx packet. */
/*
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |   h.version   |    h.type     |    h.flags    |  <reserved>   |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                          h.sessionID                          |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                        h.transactionID                        |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                          h.packetID                           |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                        h.payload_length                       |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    20 bytes in header
 */

int
agentx_check_packet(u_char *packet, size_t packet_len) {

  if (packet_len < 20)
    return 0; /* minimum header length == 20 */

  return agentx_parse_int(packet+16,
                          *(packet+2) & AGENTX_FLAGS_NETWORK_BYTE_ORDER) + 20;
}