79 lines
2.4 KiB
Go
79 lines
2.4 KiB
Go
package dtls
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import (
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"bytes"
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"context"
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"fmt"
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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/handshake"
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"github.com/pion/dtls/v2/pkg/protocol/recordlayer"
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)
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func flight2Parse(ctx context.Context, c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) (flightVal, *alert.Alert, error) {
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seq, msgs, ok := cache.fullPullMap(state.handshakeRecvSequence,
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handshakeCachePullRule{handshake.TypeClientHello, cfg.initialEpoch, true, false},
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)
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if !ok {
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// Client may retransmit the first ClientHello when HelloVerifyRequest is dropped.
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// Parse as flight 0 in this case.
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return flight0Parse(ctx, c, state, cache, cfg)
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}
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state.handshakeRecvSequence = seq
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var clientHello *handshake.MessageClientHello
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// Validate type
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if clientHello, ok = msgs[handshake.TypeClientHello].(*handshake.MessageClientHello); !ok {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, nil
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}
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if !clientHello.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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if len(clientHello.Cookie) == 0 {
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return 0, nil, nil
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}
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if !bytes.Equal(state.cookie, clientHello.Cookie) {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.AccessDenied}, errCookieMismatch
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}
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// TODO 添加 CiscoCompat 支持
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if cfg.localCiscoCompatCallback != nil {
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var err error
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state.SessionID = clientHello.SessionID
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if len(state.SessionID) == 0 {
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err = fmt.Errorf("clientHello SessionID is nil")
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.IllegalParameter}, err
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}
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state.masterSecret, err = cfg.localCiscoCompatCallback(state.SessionID)
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if err != nil {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.IllegalParameter}, err
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}
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}
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return flight4, nil, nil
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}
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func flight2Generate(c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) ([]*packet, *alert.Alert, error) {
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state.handshakeSendSequence = 0
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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.MessageHelloVerifyRequest{
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Version: protocol.Version1_2,
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Cookie: state.cookie,
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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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