133 lines
3.2 KiB
Go
133 lines
3.2 KiB
Go
package multiaddr
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import (
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"encoding/binary"
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"fmt"
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"strings"
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)
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// Protocol is a Multiaddr protocol description structure.
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type Protocol struct {
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Code int
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Size int // a size of -1 indicates a length-prefixed variable size
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Name string
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VCode []byte
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}
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// replicating table here to:
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// 1. avoid parsing the csv
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// 2. ensuring errors in the csv don't screw up code.
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// 3. changing a number has to happen in two places.
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const (
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P_IP4 = 4
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P_TCP = 6
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P_UDP = 17
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P_DCCP = 33
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P_IP6 = 41
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P_SCTP = 132
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P_UTP = 301
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P_UDT = 302
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P_IPFS = 421
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P_HTTP = 480
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P_HTTPS = 443
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P_ONION = 444
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)
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// These are special sizes
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const (
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LengthPrefixedVarSize = -1
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)
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// Protocols is the list of multiaddr protocols supported by this module.
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var Protocols = []Protocol{
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Protocol{P_IP4, 32, "ip4", CodeToVarint(P_IP4)},
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Protocol{P_TCP, 16, "tcp", CodeToVarint(P_TCP)},
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Protocol{P_UDP, 16, "udp", CodeToVarint(P_UDP)},
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Protocol{P_DCCP, 16, "dccp", CodeToVarint(P_DCCP)},
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Protocol{P_IP6, 128, "ip6", CodeToVarint(P_IP6)},
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// these require varint:
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Protocol{P_SCTP, 16, "sctp", CodeToVarint(P_SCTP)},
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Protocol{P_ONION, 80, "onion", CodeToVarint(P_ONION)},
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Protocol{P_UTP, 0, "utp", CodeToVarint(P_UTP)},
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Protocol{P_UDT, 0, "udt", CodeToVarint(P_UDT)},
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Protocol{P_HTTP, 0, "http", CodeToVarint(P_HTTP)},
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Protocol{P_HTTPS, 0, "https", CodeToVarint(P_HTTPS)},
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Protocol{P_IPFS, LengthPrefixedVarSize, "ipfs", CodeToVarint(P_IPFS)},
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}
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func AddProtocol(p Protocol) error {
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for _, pt := range Protocols {
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if pt.Code == p.Code {
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return fmt.Errorf("protocol code %d already taken by %q", p.Code, pt.Name)
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}
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if pt.Name == p.Name {
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return fmt.Errorf("protocol by the name %q already exists", p.Name)
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}
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}
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Protocols = append(Protocols, p)
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return nil
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}
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// ProtocolWithName returns the Protocol description with given string name.
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func ProtocolWithName(s string) Protocol {
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for _, p := range Protocols {
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if p.Name == s {
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return p
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}
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}
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return Protocol{}
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}
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// ProtocolWithCode returns the Protocol description with given protocol code.
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func ProtocolWithCode(c int) Protocol {
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for _, p := range Protocols {
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if p.Code == c {
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return p
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}
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}
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return Protocol{}
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}
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// ProtocolsWithString returns a slice of protocols matching given string.
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func ProtocolsWithString(s string) ([]Protocol, error) {
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s = strings.Trim(s, "/")
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sp := strings.Split(s, "/")
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if len(sp) == 0 {
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return nil, nil
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}
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t := make([]Protocol, len(sp))
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for i, name := range sp {
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p := ProtocolWithName(name)
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if p.Code == 0 {
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return nil, fmt.Errorf("no protocol with name: %s", name)
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}
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t[i] = p
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}
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return t, nil
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}
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// CodeToVarint converts an integer to a varint-encoded []byte
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func CodeToVarint(num int) []byte {
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buf := make([]byte, (num/7)+1) // varint package is uint64
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n := binary.PutUvarint(buf, uint64(num))
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return buf[:n]
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}
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// VarintToCode converts a varint-encoded []byte to an integer protocol code
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func VarintToCode(buf []byte) int {
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num, _ := ReadVarintCode(buf)
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return num
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}
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// ReadVarintCode reads a varint code from the beginning of buf.
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// returns the code, and the number of bytes read.
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func ReadVarintCode(buf []byte) (int, int) {
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num, n := binary.Uvarint(buf)
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if n < 0 {
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panic("varints larger than uint64 not yet supported")
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}
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return int(num), n
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}
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