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79 lines
2.6 KiB
Go
79 lines
2.6 KiB
Go
package yggdrasil
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// This file contains the version metadata struct
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// Used in the inital connection setup and key exchange
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// Some of this could arguably go in wire.go instead
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// This is the version-specific metadata exchanged at the start of a connection.
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// It must always beign with the 4 bytes "meta" and a wire formatted uint64 major version number.
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// The current version also includes a minor version number, and the box/sig/link keys that need to be exchanged to open an connection.
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type version_metadata struct {
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meta [4]byte
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ver uint64 // 1 byte in this version
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// Everything after this point potentially depends on the version number, and is subject to change in future versions
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minorVer uint64 // 1 byte in this version
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box boxPubKey
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sig sigPubKey
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link boxPubKey
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}
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// Gets a base metadata with no keys set, but with the correct version numbers.
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func version_getBaseMetadata() version_metadata {
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return version_metadata{
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meta: [4]byte{'m', 'e', 't', 'a'},
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ver: 0,
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minorVer: 2,
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}
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}
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// Gest the length of the metadata for this version, used to know how many bytes to read from the start of a connection.
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func version_getMetaLength() (mlen int) {
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mlen += 4 // meta
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mlen += 1 // ver, as long as it's < 127, which it is in this version
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mlen += 1 // minorVer, as long as it's < 127, which it is in this version
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mlen += boxPubKeyLen // box
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mlen += sigPubKeyLen // sig
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mlen += boxPubKeyLen // link
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return
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}
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// Encodes version metadata into its wire format.
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func (m *version_metadata) encode() []byte {
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bs := make([]byte, 0, version_getMetaLength())
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bs = append(bs, m.meta[:]...)
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bs = append(bs, wire_encode_uint64(m.ver)...)
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bs = append(bs, wire_encode_uint64(m.minorVer)...)
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bs = append(bs, m.box[:]...)
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bs = append(bs, m.sig[:]...)
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bs = append(bs, m.link[:]...)
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if len(bs) != version_getMetaLength() {
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panic("Inconsistent metadata length")
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}
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return bs
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}
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// Decodes version metadata from its wire format into the struct.
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func (m *version_metadata) decode(bs []byte) bool {
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switch {
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case !wire_chop_slice(m.meta[:], &bs):
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return false
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case !wire_chop_uint64(&m.ver, &bs):
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return false
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case !wire_chop_uint64(&m.minorVer, &bs):
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return false
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case !wire_chop_slice(m.box[:], &bs):
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return false
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case !wire_chop_slice(m.sig[:], &bs):
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return false
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case !wire_chop_slice(m.link[:], &bs):
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return false
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}
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return true
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}
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// Checks that the "meta" bytes and the version numbers are the expected values.
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func (m *version_metadata) check() bool {
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base := version_getBaseMetadata()
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return base.meta == m.meta && base.ver == m.ver && base.minorVer == m.minorVer
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}
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