90 lines
2.3 KiB
Go
90 lines
2.3 KiB
Go
package udp
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import (
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"encoding/binary"
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"fmt"
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"io"
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"time"
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"github.com/chihaya/chihaya/bittorrent"
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)
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// WriteError writes the failure reason as a null-terminated string.
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func WriteError(w io.Writer, txID []byte, err error) {
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// If the client wasn't at fault, acknowledge it.
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if _, ok := err.(bittorrent.ClientError); !ok {
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err = fmt.Errorf("internal error occurred: %s", err.Error())
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}
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buf := newBuffer()
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writeHeader(buf, txID, errorActionID)
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buf.WriteString(err.Error())
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buf.WriteRune('\000')
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w.Write(buf.Bytes())
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buf.free()
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}
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// WriteAnnounce encodes an announce response according to BEP 15.
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// The peers returned will be resp.IPv6Peers or resp.IPv4Peers, depending on
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// whether v6 is set. The action ID will be 4, according to
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// http://opentracker.blog.h3q.com/2007/12/28/the-ipv6-situation/.
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func WriteAnnounce(w io.Writer, txID []byte, resp *bittorrent.AnnounceResponse, v6 bool) {
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buf := newBuffer()
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if v6 {
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writeHeader(buf, txID, announceV6ActionID)
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} else {
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writeHeader(buf, txID, announceActionID)
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}
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binary.Write(buf, binary.BigEndian, uint32(resp.Interval/time.Second))
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binary.Write(buf, binary.BigEndian, resp.Incomplete)
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binary.Write(buf, binary.BigEndian, resp.Complete)
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peers := resp.IPv4Peers
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if v6 {
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peers = resp.IPv6Peers
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}
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for _, peer := range peers {
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buf.Write(peer.IP.IP)
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binary.Write(buf, binary.BigEndian, peer.Port)
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}
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w.Write(buf.Bytes())
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buf.free()
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}
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// WriteScrape encodes a scrape response according to BEP 15.
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func WriteScrape(w io.Writer, txID []byte, resp *bittorrent.ScrapeResponse) {
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buf := newBuffer()
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writeHeader(buf, txID, scrapeActionID)
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for _, scrape := range resp.Files {
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binary.Write(buf, binary.BigEndian, scrape.Complete)
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binary.Write(buf, binary.BigEndian, scrape.Snatches)
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binary.Write(buf, binary.BigEndian, scrape.Incomplete)
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}
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w.Write(buf.Bytes())
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buf.free()
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}
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// WriteConnectionID encodes a new connection response according to BEP 15.
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func WriteConnectionID(w io.Writer, txID, connID []byte) {
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buf := newBuffer()
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writeHeader(buf, txID, connectActionID)
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buf.Write(connID)
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w.Write(buf.Bytes())
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buf.free()
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}
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// writeHeader writes the action and transaction ID to the provided response
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// buffer.
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func writeHeader(w io.Writer, txID []byte, action uint32) {
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binary.Write(w, binary.BigEndian, action)
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w.Write(txID)
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}
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