|
| 1 | +package vpn |
| 2 | + |
| 3 | +import ( |
| 4 | +"context" |
| 5 | +"encoding/binary" |
| 6 | +"io" |
| 7 | +"sync" |
| 8 | + |
| 9 | +"google.golang.org/protobuf/proto" |
| 10 | + |
| 11 | +"cdr.dev/slog" |
| 12 | +) |
| 13 | + |
| 14 | +// MaxLength is the largest possible CoderVPN Protocol message size. This is set |
| 15 | +// so that a misbehaving peer can't cause us to allocate a huge amount of memory. |
| 16 | +constMaxLength=0x1000000// 16MiB |
| 17 | + |
| 18 | +// serdes SERializes and DESerializes protobuf messages to and from the conn. |
| 19 | +typeserdes[SrpcMessage,RreceivableRPCMessage[RR],RRany]struct { |
| 20 | +ctx context.Context |
| 21 | +logger slog.Logger |
| 22 | +conn io.ReadWriteCloser |
| 23 | +sendCh<-chanS |
| 24 | +recvChchan<-R |
| 25 | +closeOnce sync.Once |
| 26 | +wg sync.WaitGroup |
| 27 | +} |
| 28 | + |
| 29 | +func (s*serdes[_,R,RR])recvLoop() { |
| 30 | +s.logger.Debug(s.ctx,"starting recvLoop") |
| 31 | +defers.closeIdempotent() |
| 32 | +deferclose(s.recvCh) |
| 33 | +for { |
| 34 | +varlengthuint32 |
| 35 | +iferr:=binary.Read(s.conn,binary.BigEndian,&length);err!=nil { |
| 36 | +s.logger.Debug(s.ctx,"failed to read length",slog.Error(err)) |
| 37 | +return |
| 38 | +} |
| 39 | +iflength>MaxLength { |
| 40 | +s.logger.Critical(s.ctx,"message length exceeds max", |
| 41 | +slog.F("length",length)) |
| 42 | +} |
| 43 | +s.logger.Debug(s.ctx,"about to read message",slog.F("length",length)) |
| 44 | +mb:=make([]byte,length) |
| 45 | +ifn,err:=io.ReadFull(s.conn,mb);err!=nil { |
| 46 | +s.logger.Debug(s.ctx,"failed to read message", |
| 47 | +slog.Error(err), |
| 48 | +slog.F("num_bytes_read",n)) |
| 49 | +return |
| 50 | +} |
| 51 | +msg:=R(new(RR)) |
| 52 | +iferr:=proto.Unmarshal(mb,msg);err!=nil { |
| 53 | +s.logger.Critical(s.ctx,"failed to unmarshal message",slog.Error(err)) |
| 54 | +return |
| 55 | +} |
| 56 | +select { |
| 57 | +cases.recvCh<-msg: |
| 58 | +s.logger.Debug(s.ctx,"passed received message to speaker") |
| 59 | +case<-s.ctx.Done(): |
| 60 | +s.logger.Debug(s.ctx,"recvLoop canceled",slog.Error(s.ctx.Err())) |
| 61 | +} |
| 62 | +} |
| 63 | +} |
| 64 | + |
| 65 | +func (s*serdes[S,_,_])sendLoop() { |
| 66 | +s.logger.Debug(s.ctx,"starting sendLoop") |
| 67 | +defers.closeIdempotent() |
| 68 | +for { |
| 69 | +select { |
| 70 | +case<-s.ctx.Done(): |
| 71 | +s.logger.Debug(s.ctx,"sendLoop canceled",slog.Error(s.ctx.Err())) |
| 72 | +return |
| 73 | +casemsg,ok:=<-s.sendCh: |
| 74 | +if!ok { |
| 75 | +s.logger.Debug(s.ctx,"sendCh closed") |
| 76 | +return |
| 77 | +} |
| 78 | +mb,err:=proto.Marshal(msg) |
| 79 | +iferr!=nil { |
| 80 | +s.logger.Critical(s.ctx,"failed to marshal message",slog.Error(err)) |
| 81 | +return |
| 82 | +} |
| 83 | +iferr:=binary.Write(s.conn,binary.BigEndian,uint32(len(mb)));err!=nil { |
| 84 | +s.logger.Debug(s.ctx,"failed to write length",slog.Error(err)) |
| 85 | +return |
| 86 | +} |
| 87 | +if_,err:=s.conn.Write(mb);err!=nil { |
| 88 | +s.logger.Debug(s.ctx,"failed to write message",slog.Error(err)) |
| 89 | +return |
| 90 | +} |
| 91 | +} |
| 92 | +} |
| 93 | +} |
| 94 | + |
| 95 | +func (s*serdes[_,_,_])closeIdempotent() { |
| 96 | +s.closeOnce.Do(func() { |
| 97 | +iferr:=s.conn.Close();err!=nil { |
| 98 | +s.logger.Error(s.ctx,"failed to close connection",slog.Error(err)) |
| 99 | +}else { |
| 100 | +s.logger.Info(s.ctx,"closed connection") |
| 101 | +} |
| 102 | +}) |
| 103 | +} |
| 104 | + |
| 105 | +func (s*serdes[_,_,_])Close()error { |
| 106 | +s.closeIdempotent() |
| 107 | +s.wg.Wait() |
| 108 | +returnnil |
| 109 | +} |
| 110 | + |
| 111 | +func (s*serdes[_,_,_])start() { |
| 112 | +s.wg.Add(2) |
| 113 | +gofunc() { |
| 114 | +defers.wg.Done() |
| 115 | +s.recvLoop() |
| 116 | +}() |
| 117 | +gofunc() { |
| 118 | +defers.wg.Done() |
| 119 | +s.sendLoop() |
| 120 | +}() |
| 121 | +} |
| 122 | + |
| 123 | +funcnewSerdes[SrpcMessage,RreceivableRPCMessage[RR],RRany]( |
| 124 | +ctx context.Context,logger slog.Logger,conn io.ReadWriteCloser, |
| 125 | +sendCh<-chanS,recvChchan<-R, |
| 126 | +)*serdes[S,R,RR] { |
| 127 | +return&serdes[S,R,RR]{ |
| 128 | +ctx:ctx, |
| 129 | +logger:logger.Named("serdes"), |
| 130 | +conn:conn, |
| 131 | +sendCh:sendCh, |
| 132 | +recvCh:recvCh, |
| 133 | +} |
| 134 | +} |