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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package sun.security.ssl;

import java.io.IOException;

import java.security.spec.ECParameterSpec;

import java.util.HashMap;

import java.util.Map;

import javax.net.ssl.SSLProtocolException;

final class SupportedEllipticCurvesExtension extends HelloExtension {

    // the extension value to send in the ClientHello message

    static final SupportedEllipticCurvesExtension DEFAULT;

    private static final boolean fips;

    static {

        int[] ids;

        fips = SunJSSE.isFIPS();

        if (fips == false) {

            ids = new int[] {

                // NIST curves first

                // prefer NIST P-256, rest in order of increasing key length

                23, 1, 3, 19, 21, 6, 7, 9, 10, 24, 11, 12, 25, 13, 14,

                // non-NIST curves

                15, 16, 17, 2, 18, 4, 5, 20, 8, 22,

            };

        } else {

            ids = new int[] {

                // same as above, but allow only NIST curves in FIPS mode

                23, 1, 3, 19, 21, 6, 7, 9, 10, 24, 11, 12, 25, 13, 14,

            };

        }

        DEFAULT = new SupportedEllipticCurvesExtension(ids);

    }

    private final int[] curveIds;

    private SupportedEllipticCurvesExtension(int[] curveIds) {

        super(ExtensionType.EXT_ELLIPTIC_CURVES);

        this.curveIds = curveIds;

    }

    SupportedEllipticCurvesExtension(HandshakeInStream s, int len)

            throws IOException {

        super(ExtensionType.EXT_ELLIPTIC_CURVES);

        int k = s.getInt16();

        if (((len & 1) != 0) || (k + 2 != len)) {

            throw new SSLProtocolException("Invalid " + type + " extension");

        }

        curveIds = new int[k >> 1];

        for (int i = 0; i < curveIds.length; i++) {

            curveIds[i] = s.getInt16();

        }

    }

    boolean contains(int index) {

        for (int curveId : curveIds) {

            if (index == curveId) {

                return true;

            }

        }

        return false;

    }

    // Return a reference to the internal curveIds array.

    // The caller must NOT modify the contents.

    int[] curveIds() {

        return curveIds;

    }

    int length() {

        return 6 + (curveIds.length << 1);

    }

    void send(HandshakeOutStream s) throws IOException {

        s.putInt16(type.id);

        int k = curveIds.length << 1;

        s.putInt16(k + 2);

        s.putInt16(k);

        for (int curveId : curveIds) {

            s.putInt16(curveId);

        }

    }

    public String toString() {

        StringBuilder sb = new StringBuilder();

        sb.append("Extension " + type + ", curve names: {");

        boolean first = true;

        for (int curveId : curveIds) {

            if (first) {

                first = false;

            } else {

                sb.append(", ");

            }

            // first check if it is a known named curve, then try other cases.

            String oid = getCurveOid(curveId);

            if (oid != null) {

                ECParameterSpec spec = JsseJce.getECParameterSpec(oid);

                // this toString() output will look nice for the current

                // implementation of the ECParameterSpec class in the Sun

                // provider, but may not look good for other implementations.

                if (spec != null) {

                    sb.append(spec.toString().split(" ")[0]);

                } else {

                    sb.append(oid);

                }

            } else if (curveId == ARBITRARY_PRIME) {

                sb.append("arbitrary_explicit_prime_curves");

            } else if (curveId == ARBITRARY_CHAR2) {

                sb.append("arbitrary_explicit_char2_curves");

            } else {

                sb.append("unknown curve " + curveId);

            }

        }

        sb.append("}");

        return sb.toString();

    }

    // Test whether we support the curve with the given index.

    static boolean isSupported(int index) {

        if ((index <= 0) || (index >= NAMED_CURVE_OID_TABLE.length)) {

            return false;

        }

        if (fips == false) {

            // in non-FIPS mode, we support all valid indices

            return true;

        }

        return DEFAULT.contains(index);

    }

    static int getCurveIndex(ECParameterSpec params) {

        String oid = JsseJce.getNamedCurveOid(params);

        if (oid == null) {

            return -1;

        }

        Integer n = curveIndices.get(oid);

        return (n == null) ? -1 : n;

    }

    static String getCurveOid(int index) {

        if ((index > 0) && (index < NAMED_CURVE_OID_TABLE.length)) {

            return NAMED_CURVE_OID_TABLE[index];

        }

        return null;

    }

    private final static int ARBITRARY_PRIME = 0xff01;

    private final static int ARBITRARY_CHAR2 = 0xff02;

    // See sun.security.ec.NamedCurve for the OIDs

    private final static String[] NAMED_CURVE_OID_TABLE = new String[] {

        null,                   //  (0) unused

        "1.3.132.0.1",          //  (1) sect163k1, NIST K-163

        "1.3.132.0.2",          //  (2) sect163r1

        "1.3.132.0.15",         //  (3) sect163r2, NIST B-163

        "1.3.132.0.24",         //  (4) sect193r1

        "1.3.132.0.25",         //  (5) sect193r2

        "1.3.132.0.26",         //  (6) sect233k1, NIST K-233

        "1.3.132.0.27",         //  (7) sect233r1, NIST B-233

        "1.3.132.0.3",          //  (8) sect239k1

        "1.3.132.0.16",         //  (9) sect283k1, NIST K-283

        "1.3.132.0.17",         // (10) sect283r1, NIST B-283

        "1.3.132.0.36",         // (11) sect409k1, NIST K-409

        "1.3.132.0.37",         // (12) sect409r1, NIST B-409

        "1.3.132.0.38",         // (13) sect571k1, NIST K-571

        "1.3.132.0.39",         // (14) sect571r1, NIST B-571

        "1.3.132.0.9",          // (15) secp160k1

        "1.3.132.0.8",          // (16) secp160r1

        "1.3.132.0.30",         // (17) secp160r2

        "1.3.132.0.31",         // (18) secp192k1

        "1.2.840.10045.3.1.1",  // (19) secp192r1, NIST P-192

        "1.3.132.0.32",         // (20) secp224k1

        "1.3.132.0.33",         // (21) secp224r1, NIST P-224

        "1.3.132.0.10",         // (22) secp256k1

        "1.2.840.10045.3.1.7",  // (23) secp256r1, NIST P-256

        "1.3.132.0.34",         // (24) secp384r1, NIST P-384

        "1.3.132.0.35",         // (25) secp521r1, NIST P-521

    };

    private final static Map<String,Integer> curveIndices;

    static {

        curveIndices = new HashMap<String,Integer>();

        for (int i = 1; i < NAMED_CURVE_OID_TABLE.length; i++) {

            curveIndices.put(NAMED_CURVE_OID_TABLE[i], i);

        }

    }

}