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@ -7,6 +7,7 @@ package derp
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import (
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"bufio"
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crand "crypto/rand"
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"encoding/binary"
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"encoding/json"
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"errors"
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"fmt"
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@ -369,6 +370,40 @@ type KeepAliveMessage struct{}
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func (KeepAliveMessage) msg() {}
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// HealthMessage is a one-way message from server to client, declaring the
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// connection health state.
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type HealthMessage struct {
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// Problem, if non-empty, is a description of why the connection
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// is unhealthy.
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//
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// The empty string means the connection is healthy again.
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//
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// The default condition is healthy, so the server doesn't
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// broadcast a HealthMessage until a problem exists.
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Problem string
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}
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func (HealthMessage) msg() {}
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// ServerRestartingMessage is a one-way message from server to client,
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// advertising that the server is restarting.
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type ServerRestartingMessage struct {
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// ReconnectIn is an advisory duration that the client should wait
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// before attempting to reconnect. It might be zero.
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// It exists for the server to smear out the reconnects.
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ReconnectIn time.Duration
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// TryFor is an advisory duration for how long the client
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// should attempt to reconnect before giving up and proceeding
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// with its normal connection failure logic. The interval
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// between retries is undefined for now.
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// A server should not send a TryFor duration more than a few
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// seconds.
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TryFor time.Duration
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}
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func (ServerRestartingMessage) msg() {}
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// Recv reads a message from the DERP server.
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//
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// The returned message may alias memory owned by the Client; it
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@ -486,6 +521,19 @@ func (c *Client) recvTimeout(timeout time.Duration) (m ReceivedMessage, err erro
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}
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copy(pm[:], b[:])
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return pm, nil
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case frameHealth:
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return HealthMessage{Problem: string(b[:])}, nil
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case frameRestarting:
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var m ServerRestartingMessage
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if n < 8 {
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c.logf("[unexpected] dropping short server restarting frame")
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continue
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}
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m.ReconnectIn = time.Duration(binary.BigEndian.Uint32(b[0:4])) * time.Millisecond
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m.TryFor = time.Duration(binary.BigEndian.Uint32(b[4:8])) * time.Millisecond
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return m, nil
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}
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}
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}
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