75 lines
2.5 KiB
Go
75 lines
2.5 KiB
Go
// Copyright 2016 Jimmy Zelinskie
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package udp
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import (
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"bytes"
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"encoding/binary"
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"fmt"
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"time"
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"github.com/jzelinskie/trakr/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(writer 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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var buf bytes.Buffer
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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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writer.Write(buf.Bytes())
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}
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// WriteAnnounce encodes an announce response according to BEP 15.
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func WriteAnnounce(respBuf *bytes.Buffer, txID []byte, resp *bittorrent.AnnounceResponse) {
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writeHeader(respBuf, txID, announceActionID)
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binary.Write(respBuf, binary.BigEndian, uint32(resp.Interval/time.Second))
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binary.Write(respBuf, binary.BigEndian, uint32(resp.Incomplete))
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binary.Write(respBuf, binary.BigEndian, uint32(resp.Complete))
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for _, peer := range resp.IPv4Peers {
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respBuf.Write(peer.IP)
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binary.Write(respBuf, binary.BigEndian, peer.Port)
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}
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}
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// WriteScrape encodes a scrape response according to BEP 15.
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func WriteScrape(respBuf *bytes.Buffer, txID []byte, resp *bittorrent.ScrapeResponse) {
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writeHeader(respBuf, txID, scrapeActionID)
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for _, scrape := range resp.Files {
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binary.Write(respBuf, binary.BigEndian, scrape.Complete)
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binary.Write(respBuf, binary.BigEndian, scrape.Snatches)
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binary.Write(respBuf, binary.BigEndian, scrape.Incomplete)
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}
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}
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// WriteConnectionID encodes a new connection response according to BEP 15.
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func WriteConnectionID(respBuf *bytes.Buffer, txID, connID []byte) {
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writeHeader(respBuf, txID, connectActionID)
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respBuf.Write(connID)
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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(respBuf *bytes.Buffer, txID []byte, action uint32) {
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binary.Write(respBuf, binary.BigEndian, action)
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respBuf.Write(txID)
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}
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