47 lines
997 B
Go
47 lines
997 B
Go
package krpc
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import (
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"encoding/binary"
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"errors"
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"net"
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"github.com/anacrolix/missinggo"
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)
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// The size in bytes of a NodeInfo in its compact binary representation.
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const CompactIPv4NodeInfoLen = 26
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type NodeInfo struct {
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ID [20]byte
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Addr *net.UDPAddr
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}
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// Writes the node info to its compact binary representation in b. See
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// CompactNodeInfoLen.
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func (ni *NodeInfo) PutCompact(b []byte) error {
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if n := copy(b[:], ni.ID[:]); n != 20 {
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panic(n)
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}
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ip := ni.Addr.IP.To4()
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if len(ip) != 4 {
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return errors.New("expected ipv4 address")
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}
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if n := copy(b[20:], ip); n != 4 {
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panic(n)
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}
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binary.BigEndian.PutUint16(b[24:], uint16(ni.Addr.Port))
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return nil
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}
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func (ni *NodeInfo) UnmarshalCompactIPv4(b []byte) error {
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if len(b) != CompactIPv4NodeInfoLen {
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return errors.New("expected 26 bytes")
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}
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missinggo.CopyExact(ni.ID[:], b[:20])
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ni.Addr = &net.UDPAddr{
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IP: append(make([]byte, 0, 4), b[20:24]...),
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Port: int(binary.BigEndian.Uint16(b[24:26])),
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}
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return nil
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}
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