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101 lines
3.8 KiB
Go
101 lines
3.8 KiB
Go
package ntcp
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import (
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"net"
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"github.com/go-i2p/go-i2p/lib/transport/ntcp/handshake"
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"github.com/go-i2p/go-i2p/lib/transport/ntcp/messages"
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"github.com/samber/oops"
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)
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// PerformIncomingHandshake conducts the NTCP2 handshake as the responder (server).
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// It performs the server side of the 3-message handshake sequence:
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// 1. Receives and processes SessionRequest (Message 1)
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// 2. Creates and sends SessionCreated (Message 2)
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// 3. Receives and processes SessionConfirmed (Message 3)
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// After successful completion, the session is established and ready for data exchange.
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func (s *NTCP2Session) PerformIncomingHandshake(conn net.Conn) error {
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// Initialize processors if not already done
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if s.Processors == nil {
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s.Processors = make(map[messages.MessageType]handshake.HandshakeMessageProcessor)
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s.Processors[messages.MessageTypeSessionRequest] = &SessionRequestProcessor{NTCP2Session: s}
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s.Processors[messages.MessageTypeSessionCreated] = &SessionCreatedProcessor{NTCP2Session: s}
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s.Processors[messages.MessageTypeSessionConfirmed] = &SessionConfirmedProcessor{NTCP2Session: s}
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}
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// Step 1: Process SessionRequest (Message 1) from initiator
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requestProcessor, err := s.GetProcessor(messages.MessageTypeSessionRequest)
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if err != nil {
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return oops.Errorf("failed to get session request processor: %w", err)
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}
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// Read and decode SessionRequest message
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requestMsg, err := requestProcessor.ReadMessage(conn, s.HandshakeState.(*handshake.HandshakeState))
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if err != nil {
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return oops.Errorf("failed to read session request message: %w", err)
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}
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// Process SessionRequest to update handshake state
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if err := requestProcessor.ProcessMessage(requestMsg, s.HandshakeState.(*handshake.HandshakeState)); err != nil {
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return oops.Errorf("failed to process session request message: %w", err)
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}
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// Step 2: Create and send SessionCreated (Message 2)
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createdProcessor, err := s.GetProcessor(messages.MessageTypeSessionCreated)
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if err != nil {
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return oops.Errorf("failed to get session created processor: %w", err)
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}
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// Create SessionCreated message
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createdMsg, err := createdProcessor.CreateMessage(s.HandshakeState.(*handshake.HandshakeState))
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if err != nil {
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return oops.Errorf("failed to create session created message: %w", err)
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}
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// Obfuscate ephemeral key
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obfuscatedKey, err := createdProcessor.ObfuscateKey(createdMsg, s.HandshakeState.(*handshake.HandshakeState))
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if err != nil {
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return oops.Errorf("failed to obfuscate ephemeral key: %w", err)
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}
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// Encrypt payload
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encryptedPayload, err := createdProcessor.EncryptPayload(
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createdMsg,
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obfuscatedKey,
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s.HandshakeState.(*handshake.HandshakeState),
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)
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if err != nil {
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return oops.Errorf("failed to encrypt session created payload: %w", err)
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}
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// Write SessionCreated to connection
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if err := s.WriteMessageToConn(
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conn,
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obfuscatedKey,
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encryptedPayload,
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createdProcessor.GetPadding(createdMsg),
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); err != nil {
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return oops.Errorf("failed to write session created message: %w", err)
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}
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// Step 3: Process SessionConfirmed (Message 3) from initiator
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confirmedProcessor, err := s.GetProcessor(messages.MessageTypeSessionConfirmed)
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if err != nil {
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return oops.Errorf("failed to get session confirmed processor: %w", err)
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}
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// Read and decode SessionConfirmed message
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confirmedMsg, err := confirmedProcessor.ReadMessage(conn, s.HandshakeState.(*handshake.HandshakeState))
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if err != nil {
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return oops.Errorf("failed to read session confirmed message: %w", err)
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}
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// Process SessionConfirmed to finalize handshake state
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if err := confirmedProcessor.ProcessMessage(confirmedMsg, s.HandshakeState.(*handshake.HandshakeState)); err != nil {
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return oops.Errorf("failed to process session confirmed message: %w", err)
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}
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// Handshake complete, mark session as established
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return s.HandshakeState.CompleteHandshake()
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}
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