102 lines
1.9 KiB
Go
102 lines
1.9 KiB
Go
/*
|
|
Copyright 2024 Josh Deprez
|
|
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
|
you may not use this file except in compliance with the License.
|
|
You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing, software
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
See the License for the specific language governing permissions and
|
|
limitations under the License.
|
|
*/
|
|
|
|
package atalk
|
|
|
|
import (
|
|
"math/bits"
|
|
|
|
"github.com/sfiera/multitalk/pkg/ethernet"
|
|
)
|
|
|
|
// Inside AppleTalk, appendix D
|
|
var toUpperMap = [256]byte{
|
|
// The alphabet
|
|
0x61: 0x41,
|
|
0x62: 0x42,
|
|
0x63: 0x43,
|
|
0x64: 0x44,
|
|
0x65: 0x45,
|
|
0x66: 0x46,
|
|
0x67: 0x47,
|
|
0x68: 0x48,
|
|
0x69: 0x49,
|
|
0x6A: 0x4A,
|
|
0x6B: 0x4B,
|
|
0x6C: 0x4C,
|
|
0x6D: 0x4D,
|
|
0x6E: 0x4E,
|
|
0x6F: 0x4F,
|
|
0x70: 0x50,
|
|
0x71: 0x51,
|
|
0x72: 0x52,
|
|
0x73: 0x53,
|
|
0x74: 0x54,
|
|
0x75: 0x55,
|
|
0x76: 0x56,
|
|
0x77: 0x57,
|
|
0x78: 0x58,
|
|
0x79: 0x59,
|
|
0x7A: 0x5A,
|
|
|
|
// Letters with diacritics, etc
|
|
0x88: 0xCB,
|
|
0x8A: 0x80,
|
|
0x8B: 0xCC,
|
|
0x8C: 0x81,
|
|
0x8D: 0x82,
|
|
0x8E: 0x83,
|
|
0x96: 0x84,
|
|
0x9A: 0x85,
|
|
0x9B: 0xCD,
|
|
0x9F: 0x86,
|
|
0xBE: 0xAE,
|
|
0xBF: 0xAF,
|
|
0xCF: 0xCE,
|
|
}
|
|
|
|
func Checksum(s string) uint16 {
|
|
// Inside AppleTalk, pp 4-17 and pp 8-18
|
|
var cksum uint16
|
|
for _, b := range []byte(s) {
|
|
cksum += uint16(b)
|
|
cksum = bits.RotateLeft16(cksum, -1)
|
|
}
|
|
if cksum == 0 {
|
|
cksum = 0xFFFF
|
|
}
|
|
return cksum
|
|
}
|
|
|
|
func ToUpper(s string) string {
|
|
// Inside Appletalk, appendix D
|
|
sb := []byte(s)
|
|
out := make([]byte, len(sb))
|
|
for i, b := range sb {
|
|
if u := toUpperMap[b]; u != 0 {
|
|
out[i] = u
|
|
} else {
|
|
out[i] = b
|
|
}
|
|
}
|
|
return string(out)
|
|
}
|
|
|
|
func MulticastAddr(zone string) ethernet.Addr {
|
|
// Inside AppleTalk, pp 3-10 and pp 8-18
|
|
h := Checksum(ToUpper(zone))
|
|
return ethernet.Addr{0x09, 0x00, 0x07, 0x00, 0x00, byte(h % 0xFD)}
|
|
}
|