130 lines
4.2 KiB
Go
130 lines
4.2 KiB
Go
package dtls
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import (
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"context"
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"github.com/pion/dtls/v2/pkg/crypto/elliptic"
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"github.com/pion/dtls/v2/pkg/protocol"
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"github.com/pion/dtls/v2/pkg/protocol/alert"
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"github.com/pion/dtls/v2/pkg/protocol/extension"
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"github.com/pion/dtls/v2/pkg/protocol/handshake"
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"github.com/pion/dtls/v2/pkg/protocol/recordlayer"
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)
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func flight1Parse(ctx context.Context, c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) (flightVal, *alert.Alert, error) {
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// HelloVerifyRequest can be skipped by the server,
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// so allow ServerHello during flight1 also
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seq, msgs, ok := cache.fullPullMap(state.handshakeRecvSequence,
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handshakeCachePullRule{handshake.TypeHelloVerifyRequest, cfg.initialEpoch, false, true},
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handshakeCachePullRule{handshake.TypeServerHello, cfg.initialEpoch, false, true},
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)
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if !ok {
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// No valid message received. Keep reading
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return 0, nil, nil
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}
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if _, ok := msgs[handshake.TypeServerHello]; ok {
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// Flight1 and flight2 were skipped.
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// Parse as flight3.
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return flight3Parse(ctx, c, state, cache, cfg)
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}
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if h, ok := msgs[handshake.TypeHelloVerifyRequest].(*handshake.MessageHelloVerifyRequest); ok {
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// DTLS 1.2 clients must not assume that the server will use the protocol version
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// specified in HelloVerifyRequest message. RFC 6347 Section 4.2.1
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if !h.Version.Equal(protocol.Version1_0) && !h.Version.Equal(protocol.Version1_2) {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.ProtocolVersion}, errUnsupportedProtocolVersion
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}
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state.cookie = append([]byte{}, h.Cookie...)
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state.handshakeRecvSequence = seq
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return flight3, nil, nil
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}
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, nil
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}
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func flight1Generate(c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) ([]*packet, *alert.Alert, error) {
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var zeroEpoch uint16
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state.localEpoch.Store(zeroEpoch)
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state.remoteEpoch.Store(zeroEpoch)
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state.namedCurve = defaultNamedCurve
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state.cookie = nil
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if err := state.localRandom.Populate(); err != nil {
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return nil, nil, err
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}
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extensions := []extension.Extension{
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&extension.SupportedSignatureAlgorithms{
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SignatureHashAlgorithms: cfg.localSignatureSchemes,
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},
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&extension.RenegotiationInfo{
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RenegotiatedConnection: 0,
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},
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}
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if cfg.localPSKCallback == nil {
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extensions = append(extensions, []extension.Extension{
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&extension.SupportedEllipticCurves{
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EllipticCurves: []elliptic.Curve{elliptic.X25519, elliptic.P256, elliptic.P384},
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},
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&extension.SupportedPointFormats{
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PointFormats: []elliptic.CurvePointFormat{elliptic.CurvePointFormatUncompressed},
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},
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}...)
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}
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if len(cfg.localSRTPProtectionProfiles) > 0 {
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extensions = append(extensions, &extension.UseSRTP{
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ProtectionProfiles: cfg.localSRTPProtectionProfiles,
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})
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}
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if cfg.extendedMasterSecret == RequestExtendedMasterSecret ||
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cfg.extendedMasterSecret == RequireExtendedMasterSecret {
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extensions = append(extensions, &extension.UseExtendedMasterSecret{
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Supported: true,
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})
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}
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if len(cfg.serverName) > 0 {
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extensions = append(extensions, &extension.ServerName{ServerName: cfg.serverName})
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}
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if len(cfg.supportedProtocols) > 0 {
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extensions = append(extensions, &extension.ALPN{ProtocolNameList: cfg.supportedProtocols})
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}
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if cfg.sessionStore != nil {
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cfg.log.Tracef("[handshake] try to resume session")
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if s, err := cfg.sessionStore.Get(c.sessionKey()); err != nil {
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return nil, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
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} else if s.ID != nil {
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cfg.log.Tracef("[handshake] get saved session: %x", s.ID)
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state.SessionID = s.ID
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state.masterSecret = s.Secret
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}
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}
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return []*packet{
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{
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record: &recordlayer.RecordLayer{
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Header: recordlayer.Header{
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Version: protocol.Version1_2,
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},
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Content: &handshake.Handshake{
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Message: &handshake.MessageClientHello{
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Version: protocol.Version1_2,
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SessionID: state.SessionID,
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Cookie: state.cookie,
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Random: state.localRandom,
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CipherSuiteIDs: cipherSuiteIDs(cfg.localCipherSuites),
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CompressionMethods: defaultCompressionMethods(),
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Extensions: extensions,
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},
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},
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},
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},
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}, nil, nil
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}
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