Include PeerConn prefix for log messages

[btrtrc.git] / peer_protocol / handshake.go

diff --git a/peer_protocol/handshake.go b/peer_protocol/handshake.go
index ba81a0cf385974123f5734dd990c6780364009f9..454cc2460bb90a206ffab9eb9fcba0dfa485dc77 100644 (file)
--- a/peer_protocol/handshake.go
+++ b/peer_protocol/handshake.go
@@ -5,17 +5,30 @@ import (
        "errors"
        "fmt"
        "io"
+       "math/bits"
        "strconv"
+       "strings"
+       "unsafe"
 
        "github.com/anacrolix/torrent/metainfo"
 )
 
 type ExtensionBit uint
 
+// https://www.bittorrent.org/beps/bep_0004.html
+// https://wiki.theory.org/BitTorrentSpecification.html#Reserved_Bytes
 const (
-       ExtensionBitDHT      = 0  // http://www.bittorrent.org/beps/bep_0005.html
-       ExtensionBitExtended = 20 // http://www.bittorrent.org/beps/bep_0010.html
-       ExtensionBitFast     = 2  // http://www.bittorrent.org/beps/bep_0006.html
+       ExtensionBitDht                          = 0 // http://www.bittorrent.org/beps/bep_0005.html
+       ExtensionBitFast                         = 2 // http://www.bittorrent.org/beps/bep_0006.html
+       ExtensionBitV2                           = 7 // "Hybrid torrent legacy to v2 upgrade"
+       ExtensionBitAzureusExtensionNegotiation1 = 16
+       ExtensionBitAzureusExtensionNegotiation2 = 17
+       // LibTorrent Extension Protocol, http://www.bittorrent.org/beps/bep_0010.html
+       ExtensionBitLtep = 20
+       // https://wiki.theory.org/BitTorrent_Location-aware_Protocol_1
+       ExtensionBitLocationAwareProtocol    = 43
+       ExtensionBitAzureusMessagingProtocol = 63 // https://www.bittorrent.org/beps/bep_0004.html
+
 )
 
 func handshakeWriter(w io.Writer, bb <-chan []byte, done chan<- error) {
@@ -33,8 +46,36 @@ type (
        PeerExtensionBits [8]byte
 )
 
+var bitTags = []struct {
+       bit ExtensionBit
+       tag string
+}{
+       // Ordered by their bit position left to right.
+       {ExtensionBitAzureusMessagingProtocol, "amp"},
+       {ExtensionBitLocationAwareProtocol, "loc"},
+       {ExtensionBitLtep, "ltep"},
+       {ExtensionBitAzureusExtensionNegotiation2, "azen2"},
+       {ExtensionBitAzureusExtensionNegotiation1, "azen1"},
+       {ExtensionBitV2, "v2"},
+       {ExtensionBitFast, "fast"},
+       {ExtensionBitDht, "dht"},
+}
+
 func (pex PeerExtensionBits) String() string {
-       return hex.EncodeToString(pex[:])
+       pexHex := hex.EncodeToString(pex[:])
+       tags := make([]string, 0, len(bitTags)+1)
+       for _, bitTag := range bitTags {
+               if pex.GetBit(bitTag.bit) {
+                       tags = append(tags, bitTag.tag)
+                       pex.SetBit(bitTag.bit, false)
+               }
+       }
+       unknownCount := bits.OnesCount64(*(*uint64)((unsafe.Pointer(unsafe.SliceData(pex[:])))))
+       if unknownCount != 0 {
+               tags = append(tags, fmt.Sprintf("%v unknown", unknownCount))
+       }
+       return fmt.Sprintf("%v (%s)", pexHex, strings.Join(tags, ", "))
+
 }
 
 func NewPeerExtensionBytes(bits ...ExtensionBit) (ret PeerExtensionBits) {
@@ -45,11 +86,11 @@ func NewPeerExtensionBytes(bits ...ExtensionBit) (ret PeerExtensionBits) {
 }
 
 func (pex PeerExtensionBits) SupportsExtended() bool {
-       return pex.GetBit(ExtensionBitExtended)
+       return pex.GetBit(ExtensionBitLtep)
 }
 
 func (pex PeerExtensionBits) SupportsDHT() bool {
-       return pex.GetBit(ExtensionBitDHT)
+       return pex.GetBit(ExtensionBitDht)
 }
 
 func (pex PeerExtensionBits) SupportsFast() bool {
@@ -124,9 +165,9 @@ func Handshake(
                return res, errors.New("unexpected protocol string")
        }
 
-       copyExact := func(dst []byte, src []byte) {
+       copyExact := func(dst, src []byte) {
                if dstLen, srcLen := uint64(len(dst)), uint64(len(src)); dstLen != srcLen {
-                       panic("dst len " + strconv.FormatUint(dstLen,10) + " != src len " + strconv.FormatUint(srcLen,10))
+                       panic("dst len " + strconv.FormatUint(dstLen, 10) + " != src len " + strconv.FormatUint(srcLen, 10))
                }
                copy(dst, src)
        }