src/share/classes/sun/security/ssl/Record.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * accompanied this code).
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package sun.security.ssl;


/**
 * SSL/TLS records, as pulled off (and put onto) a TCP stream.  This is
 * the base interface, which defines common information and interfaces
 * used by both Input and Output records.
 *
 * @author David Brownell
 */
interface Record {
    /*
     * There are four SSL record types, which are part of the interface
     * to this level (along with the maximum record size)
     *
     * enum { change_cipher_spec(20), alert(21), handshake(22),
     *      application_data(23), (255) } ContentType;
     */
    static final byte   ct_change_cipher_spec = 20;
    static final byte   ct_alert = 21;
    static final byte   ct_handshake = 22;
    static final byte   ct_application_data = 23;

    static final int            headerSize = 5;         // SSLv3 record header
    static final int            maxExpansion = 1024;    // for bad compression
    static final int            trailerSize = 20;       // SHA1 hash size
    static final int            maxDataSize = 16384;    // 2^14 bytes of data
    static final int            maxPadding = 256;       // block cipher padding

    /*
     * SSL has a maximum record size.  It's header, (compressed) data,
     * padding, and a trailer for the MAC.
     * Some compression algorithms have rare cases where they expand the data.
     * As we don't support compression at this time, leave that out.
     */
    static final int            maxRecordSize =
                                      headerSize        // header
                                    + maxDataSize       // data
                                    + maxPadding        // padding
                                    + trailerSize;      // MAC

    /*
     * The maximum large record size.
     *
     * Some SSL/TLS implementations support large fragment upto 2^15 bytes,
     * such as Microsoft. We support large incoming fragments.
     *
     * The maximum large record size is defined as maxRecordSize plus 2^14,
     * this is the amount OpenSSL is using.
     */
    static final int            maxLargeRecordSize =
                maxRecordSize   // Max size with a conforming implemenation
              + maxDataSize;    // extra 2^14 bytes for large data packets.


    /*
     * Maximum record size for alert and change cipher spec records.
     * They only contain 2 and 1 bytes of data, respectively.
     * Allocate a smaller array.
     */
    static final int maxAlertRecordSize =
                        headerSize + 2 + maxPadding + trailerSize;

}