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codec.go
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codec.go
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package multiaddr
import (
"encoding/base32"
"encoding/binary"
"errors"
"fmt"
"net"
"strconv"
"strings"
mh "github.com/jbenet/go-multihash"
)
func stringToBytes(s string) ([]byte, error) {
// consume trailing slashes
s = strings.TrimRight(s, "/")
b := []byte{}
sp := strings.Split(s, "/")
if sp[0] != "" {
return nil, fmt.Errorf("invalid multiaddr, must begin with /")
}
// consume first empty elem
sp = sp[1:]
for len(sp) > 0 {
p := ProtocolWithName(sp[0])
if p.Code == 0 {
return nil, fmt.Errorf("no protocol with name %s", sp[0])
}
b = append(b, CodeToVarint(p.Code)...)
sp = sp[1:]
if p.Size == 0 { // no length.
continue
}
if len(sp) < 1 {
return nil, fmt.Errorf("protocol requires address, none given: %s", p.Name)
}
a, err := addressStringToBytes(p, sp[0])
if err != nil {
return nil, fmt.Errorf("failed to parse %s: %s %s", p.Name, sp[0], err)
}
b = append(b, a...)
sp = sp[1:]
}
return b, nil
}
func bytesToString(b []byte) (ret string, err error) {
// panic handler, in case we try accessing bytes incorrectly.
defer func() {
if e := recover(); e != nil {
ret = ""
switch e := e.(type) {
case error:
err = e
case string:
err = errors.New(e)
default:
err = fmt.Errorf("%v", e)
}
}
}()
s := ""
for len(b) > 0 {
code, n := ReadVarintCode(b)
b = b[n:]
p := ProtocolWithCode(code)
if p.Code == 0 {
return "", fmt.Errorf("no protocol with code %d", code)
}
s += "/" + p.Name
if p.Size == 0 {
continue
}
size := sizeForAddr(p, b)
a, err := addressBytesToString(p, b[:size])
if err != nil {
return "", err
}
if len(a) > 0 {
s += "/" + a
}
b = b[size:]
}
return s, nil
}
func sizeForAddr(p Protocol, b []byte) int {
switch {
case p.Size > 0:
return (p.Size / 8)
case p.Size == 0:
return 0
default:
size, n := ReadVarintCode(b)
return size + n
}
}
func bytesSplit(b []byte) (ret [][]byte, err error) {
// panic handler, in case we try accessing bytes incorrectly.
defer func() {
if e := recover(); e != nil {
ret = [][]byte{}
err = e.(error)
}
}()
ret = [][]byte{}
for len(b) > 0 {
code, n := ReadVarintCode(b)
p := ProtocolWithCode(code)
if p.Code == 0 {
return [][]byte{}, fmt.Errorf("no protocol with code %d", b[0])
}
size := sizeForAddr(p, b[n:])
length := n + size
ret = append(ret, b[:length])
b = b[length:]
}
return ret, nil
}
func addressStringToBytes(p Protocol, s string) ([]byte, error) {
switch p.Code {
case P_IP4: // ipv4
i := net.ParseIP(s).To4()
if i == nil {
return nil, fmt.Errorf("failed to parse ip4 addr: %s", s)
}
return i, nil
case P_IP6: // ipv6
i := net.ParseIP(s).To16()
if i == nil {
return nil, fmt.Errorf("failed to parse ip6 addr: %s", s)
}
return i, nil
// tcp udp dccp sctp
case P_TCP, P_UDP, P_DCCP, P_SCTP:
i, err := strconv.Atoi(s)
if err != nil {
return nil, fmt.Errorf("failed to parse %s addr: %s", p.Name, err)
}
if i >= 65536 {
return nil, fmt.Errorf("failed to parse %s addr: %s", p.Name, "greater than 65536")
}
b := make([]byte, 2)
binary.BigEndian.PutUint16(b, uint16(i))
return b, nil
case P_ONION:
addr := strings.Split(s, ":")
if len(addr) != 2 {
return nil, fmt.Errorf("failed to parse %s addr: %s does not contain a port number.", p.Name, s)
}
// onion address without the ".onion" substring
if len(addr[0]) != 16 {
return nil, fmt.Errorf("failed to parse %s addr: %s not a Tor onion address.", p.Name, s)
}
onionHostBytes, err := base32.StdEncoding.DecodeString(strings.ToUpper(addr[0]))
if err != nil {
return nil, fmt.Errorf("failed to decode base32 %s addr: %s %s", p.Name, s, err)
}
// onion port number
i, err := strconv.Atoi(addr[1])
if err != nil {
return nil, fmt.Errorf("failed to parse %s addr: %s", p.Name, err)
}
if i >= 65536 {
return nil, fmt.Errorf("failed to parse %s addr: %s", p.Name, "port greater than 65536")
}
if i < 1 {
return nil, fmt.Errorf("failed to parse %s addr: %s", p.Name, "port less than 1")
}
onionPortBytes := make([]byte, 2)
binary.BigEndian.PutUint16(onionPortBytes, uint16(i))
bytes := []byte{}
bytes = append(bytes, onionHostBytes...)
bytes = append(bytes, onionPortBytes...)
return bytes, nil
case P_IPFS: // ipfs
// the address is a varint prefixed multihash string representation
m, err := mh.FromB58String(s)
if err != nil {
return nil, fmt.Errorf("failed to parse ipfs addr: %s %s", s, err)
}
size := CodeToVarint(len(m))
b := append(size, m...)
return b, nil
}
return []byte{}, fmt.Errorf("failed to parse %s addr: unknown", p.Name)
}
func addressBytesToString(p Protocol, b []byte) (string, error) {
switch p.Code {
// ipv4,6
case P_IP4, P_IP6:
return net.IP(b).String(), nil
// tcp udp dccp sctp
case P_TCP, P_UDP, P_DCCP, P_SCTP:
i := binary.BigEndian.Uint16(b)
return strconv.Itoa(int(i)), nil
case P_IPFS: // ipfs
// the address is a varint-prefixed multihash string representation
size, n := ReadVarintCode(b)
b = b[n:]
if len(b) != size {
panic("inconsistent lengths")
}
m, err := mh.Cast(b)
if err != nil {
return "", err
}
return m.B58String(), nil
}
return "", fmt.Errorf("unknown protocol")
}