From 5bdc1159433138d92ed6fefb253e3c6ed3a43995 Mon Sep 17 00:00:00 2001 From: Felix Lange Date: Thu, 5 Feb 2015 03:07:58 +0100 Subject: p2p: integrate p2p/discover Overview of changes: - ClientIdentity has been removed, use discover.NodeID - Server now requires a private key to be set (instead of public key) - Server performs the encryption handshake before launching Peer - Dial logic takes peers from discover table - Encryption handshake code has been cleaned up a bit - baseProtocol is gone because we don't exchange peers anymore - Some parts of baseProtocol have moved into Peer instead --- p2p/message.go | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 107 insertions(+), 10 deletions(-) (limited to 'p2p/message.go') diff --git a/p2p/message.go b/p2p/message.go index daf2bf05c..6521d09c2 100644 --- a/p2p/message.go +++ b/p2p/message.go @@ -1,6 +1,7 @@ package p2p import ( + "bufio" "bytes" "encoding/binary" "errors" @@ -8,7 +9,10 @@ import ( "io" "io/ioutil" "math/big" + "net" + "sync" "sync/atomic" + "time" "github.com/ethereum/go-ethereum/ethutil" "github.com/ethereum/go-ethereum/rlp" @@ -74,11 +78,14 @@ type MsgWriter interface { // WriteMsg sends a message. It will block until the message's // Payload has been consumed by the other end. // - // Note that messages can be sent only once. + // Note that messages can be sent only once because their + // payload reader is drained. WriteMsg(Msg) error } // MsgReadWriter provides reading and writing of encoded messages. +// Implementations should ensure that ReadMsg and WriteMsg can be +// called simultaneously from multiple goroutines. type MsgReadWriter interface { MsgReader MsgWriter @@ -90,8 +97,45 @@ func EncodeMsg(w MsgWriter, code uint64, data ...interface{}) error { return w.WriteMsg(NewMsg(code, data...)) } +// frameRW is a MsgReadWriter that reads and writes devp2p message frames. +// As required by the interface, ReadMsg and WriteMsg can be called from +// multiple goroutines. +type frameRW struct { + net.Conn // make Conn methods available. be careful. + bufconn *bufio.ReadWriter + + // this channel is used to 'lend' bufconn to a caller of ReadMsg + // until the message payload has been consumed. the channel + // receives a value when EOF is reached on the payload, unblocking + // a pending call to ReadMsg. + rsync chan struct{} + + // this mutex guards writes to bufconn. + writeMu sync.Mutex +} + +func newFrameRW(conn net.Conn, timeout time.Duration) *frameRW { + rsync := make(chan struct{}, 1) + rsync <- struct{}{} + return &frameRW{ + Conn: conn, + bufconn: bufio.NewReadWriter(bufio.NewReader(conn), bufio.NewWriter(conn)), + rsync: rsync, + } +} + var magicToken = []byte{34, 64, 8, 145} +func (rw *frameRW) WriteMsg(msg Msg) error { + rw.writeMu.Lock() + defer rw.writeMu.Unlock() + rw.SetWriteDeadline(time.Now().Add(msgWriteTimeout)) + if err := writeMsg(rw.bufconn, msg); err != nil { + return err + } + return rw.bufconn.Flush() +} + func writeMsg(w io.Writer, msg Msg) error { // TODO: handle case when Size + len(code) + len(listhdr) overflows uint32 code := ethutil.Encode(uint32(msg.Code)) @@ -120,12 +164,16 @@ func makeListHeader(length uint32) []byte { return append([]byte{lenb}, enc...) } -// readMsg reads a message header from r. -// It takes an rlp.ByteReader to ensure that the decoding doesn't buffer. -func readMsg(r rlp.ByteReader) (msg Msg, err error) { +func (rw *frameRW) ReadMsg() (msg Msg, err error) { + <-rw.rsync // wait until bufconn is ours + + // this read timeout applies also to the payload. + // TODO: proper read timeout + rw.SetReadDeadline(time.Now().Add(msgReadTimeout)) + // read magic and payload size start := make([]byte, 8) - if _, err = io.ReadFull(r, start); err != nil { + if _, err = io.ReadFull(rw.bufconn, start); err != nil { return msg, newPeerError(errRead, "%v", err) } if !bytes.HasPrefix(start, magicToken) { @@ -134,17 +182,33 @@ func readMsg(r rlp.ByteReader) (msg Msg, err error) { size := binary.BigEndian.Uint32(start[4:]) // decode start of RLP message to get the message code - posr := &postrack{r, 0} + posr := &postrack{rw.bufconn, 0} s := rlp.NewStream(posr) if _, err := s.List(); err != nil { return msg, err } - code, err := s.Uint() + msg.Code, err = s.Uint() if err != nil { return msg, err } - payloadsize := size - posr.p - return Msg{code, payloadsize, io.LimitReader(r, int64(payloadsize))}, nil + msg.Size = size - posr.p + + if msg.Size <= wholePayloadSize { + // msg is small, read all of it and move on to the next message. + pbuf := make([]byte, msg.Size) + if _, err := io.ReadFull(rw.bufconn, pbuf); err != nil { + return msg, err + } + rw.rsync <- struct{}{} // bufconn is available again + msg.Payload = bytes.NewReader(pbuf) + } else { + // lend bufconn to the caller until it has + // consumed the payload. eofSignal will send a value + // on rw.rsync when EOF is reached. + pr := &eofSignal{rw.bufconn, msg.Size, rw.rsync} + msg.Payload = pr + } + return msg, nil } // postrack wraps an rlp.ByteReader with a position counter. @@ -167,6 +231,39 @@ func (r *postrack) ReadByte() (byte, error) { return b, err } +// eofSignal wraps a reader with eof signaling. the eof channel is +// closed when the wrapped reader returns an error or when count bytes +// have been read. +type eofSignal struct { + wrapped io.Reader + count uint32 // number of bytes left + eof chan<- struct{} +} + +// note: when using eofSignal to detect whether a message payload +// has been read, Read might not be called for zero sized messages. +func (r *eofSignal) Read(buf []byte) (int, error) { + if r.count == 0 { + if r.eof != nil { + r.eof <- struct{}{} + r.eof = nil + } + return 0, io.EOF + } + + max := len(buf) + if int(r.count) < len(buf) { + max = int(r.count) + } + n, err := r.wrapped.Read(buf[:max]) + r.count -= uint32(n) + if (err != nil || r.count == 0) && r.eof != nil { + r.eof <- struct{}{} // tell Peer that msg has been consumed + r.eof = nil + } + return n, err +} + // MsgPipe creates a message pipe. Reads on one end are matched // with writes on the other. The pipe is full-duplex, both ends // implement MsgReadWriter. @@ -198,7 +295,7 @@ type MsgPipeRW struct { func (p *MsgPipeRW) WriteMsg(msg Msg) error { if atomic.LoadInt32(p.closed) == 0 { consumed := make(chan struct{}, 1) - msg.Payload = &eofSignal{msg.Payload, int64(msg.Size), consumed} + msg.Payload = &eofSignal{msg.Payload, msg.Size, consumed} select { case p.w <- msg: if msg.Size > 0 { -- cgit v1.2.3 From e34d1341022a51d8a86c4836c91e4e0ded888d27 Mon Sep 17 00:00:00 2001 From: Felix Lange Date: Sat, 7 Feb 2015 00:13:22 +0100 Subject: p2p: fixes for actual connections The unit test hooks were turned on 'in production'. --- p2p/message.go | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'p2p/message.go') diff --git a/p2p/message.go b/p2p/message.go index 6521d09c2..dfc33f349 100644 --- a/p2p/message.go +++ b/p2p/message.go @@ -174,10 +174,10 @@ func (rw *frameRW) ReadMsg() (msg Msg, err error) { // read magic and payload size start := make([]byte, 8) if _, err = io.ReadFull(rw.bufconn, start); err != nil { - return msg, newPeerError(errRead, "%v", err) + return msg, err } if !bytes.HasPrefix(start, magicToken) { - return msg, newPeerError(errMagicTokenMismatch, "got %x, want %x", start[:4], magicToken) + return msg, fmt.Errorf("bad magic token %x", start[:4], magicToken) } size := binary.BigEndian.Uint32(start[4:]) -- cgit v1.2.3 From 5110f80bba13e3758ae1836a88afee123df81e3e Mon Sep 17 00:00:00 2001 From: Felix Lange Date: Fri, 13 Feb 2015 14:44:00 +0100 Subject: p2p: improve read deadlines There are now two deadlines, frameReadTimeout and payloadReadTimeout. The frame timeout is longer and allows for connections that are idle. The message timeout is still short and ensures that we don't get stuck in the middle of a message. --- p2p/message.go | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-) (limited to 'p2p/message.go') diff --git a/p2p/message.go b/p2p/message.go index dfc33f349..07916f7b3 100644 --- a/p2p/message.go +++ b/p2p/message.go @@ -18,6 +18,28 @@ import ( "github.com/ethereum/go-ethereum/rlp" ) +// parameters for frameRW +const ( + // maximum time allowed for reading a message header. + // this is effectively the amount of time a connection can be idle. + frameReadTimeout = 1 * time.Minute + + // maximum time allowed for reading the payload data of a message. + // this is shorter than (and distinct from) frameReadTimeout because + // the connection is not considered idle while a message is transferred. + // this also limits the payload size of messages to how much the connection + // can transfer within the timeout. + payloadReadTimeout = 5 * time.Second + + // maximum amount of time allowed for writing a complete message. + msgWriteTimeout = 5 * time.Second + + // messages smaller than this many bytes will be read at + // once before passing them to a protocol. this increases + // concurrency in the processing. + wholePayloadSize = 64 * 1024 +) + // Msg defines the structure of a p2p message. // // Note that a Msg can only be sent once since the Payload reader is @@ -167,9 +189,7 @@ func makeListHeader(length uint32) []byte { func (rw *frameRW) ReadMsg() (msg Msg, err error) { <-rw.rsync // wait until bufconn is ours - // this read timeout applies also to the payload. - // TODO: proper read timeout - rw.SetReadDeadline(time.Now().Add(msgReadTimeout)) + rw.SetReadDeadline(time.Now().Add(frameReadTimeout)) // read magic and payload size start := make([]byte, 8) @@ -193,6 +213,8 @@ func (rw *frameRW) ReadMsg() (msg Msg, err error) { } msg.Size = size - posr.p + rw.SetReadDeadline(time.Now().Add(payloadReadTimeout)) + if msg.Size <= wholePayloadSize { // msg is small, read all of it and move on to the next message. pbuf := make([]byte, msg.Size) -- cgit v1.2.3