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parse the packet header before getting the session from the session map

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This commit is contained in:
Marten Seemann
2017-11-09 20:52:52 +07:00
parent dd722758af
commit 5d4174b2f0
8 changed files with 144 additions and 173 deletions
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49
server.go
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@@ -219,38 +219,25 @@ func (s *server) handlePacket(pconn net.PacketConn, remoteAddr net.Addr, packet
rcvTime := time.Now()
r := bytes.NewReader(packet)
connID, err := wire.PeekConnectionID(r)
if err != nil {
return qerr.Error(qerr.InvalidPacketHeader, err.Error())
}
s.sessionsMutex.RLock()
session, ok := s.sessions[connID]
s.sessionsMutex.RUnlock()
if ok && session == nil {
// Late packet for closed session
return nil
}
version := protocol.VersionUnknown
if ok {
version = session.GetVersion()
}
hdr, err := wire.ParseHeader(r, protocol.PerspectiveClient, version)
if err == wire.ErrPacketWithUnknownVersion {
_, err = pconn.WriteTo(wire.WritePublicReset(connID, 0, 0), remoteAddr)
return err
}
hdr, err := wire.ParseHeaderSentByClient(r)
if err != nil {
return qerr.Error(qerr.InvalidPacketHeader, err.Error())
}
hdr.Raw = packet[:len(packet)-r.Len()]
connID := hdr.ConnectionID
s.sessionsMutex.RLock()
session, sessionKnown := s.sessions[connID]
s.sessionsMutex.RUnlock()
if sessionKnown && session == nil {
// Late packet for closed session
return nil
}
// ignore all Public Reset packets
if hdr.ResetFlag {
if ok {
if sessionKnown {
var pr *wire.PublicReset
pr, err = wire.ParsePublicReset(r)
if err != nil {
@@ -264,10 +251,18 @@ func (s *server) handlePacket(pconn net.PacketConn, remoteAddr net.Addr, packet
return nil
}
// If we don't have a session for this connection, and this packet cannot open a new connection, send a Public Reset
// This should only happen after a server restart, when we still receive packets for connections that we lost the state for.
// TODO(#943): implement sending of IETF draft style stateless resets
if !sessionKnown && (!hdr.VersionFlag && hdr.Type != protocol.PacketTypeInitial) {
_, err = pconn.WriteTo(wire.WritePublicReset(connID, 0, 0), remoteAddr)
return err
}
// a session is only created once the client sent a supported version
// if we receive a packet for a connection that already has session, it's probably an old packet that was sent by the client before the version was negotiated
// it is safe to drop it
if ok && hdr.VersionFlag && !protocol.IsSupportedVersion(s.config.Versions, hdr.Version) {
if sessionKnown && hdr.VersionFlag && !protocol.IsSupportedVersion(s.config.Versions, hdr.Version) {
return nil
}
@@ -289,7 +284,7 @@ func (s *server) handlePacket(pconn net.PacketConn, remoteAddr net.Addr, packet
return err
}
if !ok {
if !sessionKnown {
version := hdr.Version
if !protocol.IsSupportedVersion(s.config.Versions, version) {
return errors.New("Server BUG: negotiated version not supported")