forked from quic-go/quic-go
94 lines
2.4 KiB
Go
94 lines
2.4 KiB
Go
package protocol
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import (
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"fmt"
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)
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// VersionNumber is a version number as int
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type VersionNumber int
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// gQUIC version range as defined in the wiki: https://github.com/quicwg/base-drafts/wiki/QUIC-Versions
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const (
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gquicVersion0 = 0x51303030
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maxGquicVersion = 0x51303439
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)
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// The version numbers, making grepping easier
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const (
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Version37 VersionNumber = gquicVersion0 + 3*0x100 + 0x7 + iota
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Version38
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Version39
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VersionTLS VersionNumber = 101
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VersionWhatever VersionNumber = 0 // for when the version doesn't matter
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VersionUnsupported VersionNumber = -1
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VersionUnknown VersionNumber = -2
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)
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// SupportedVersions lists the versions that the server supports
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// must be in sorted descending order
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var SupportedVersions = []VersionNumber{
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Version39,
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Version38,
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Version37,
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}
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// UsesTLS says if this QUIC version uses TLS 1.3 for the handshake
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func (vn VersionNumber) UsesTLS() bool {
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return vn == VersionTLS
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}
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func (vn VersionNumber) String() string {
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switch vn {
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case VersionWhatever:
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return "whatever"
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case VersionUnsupported:
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return "unsupported"
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case VersionUnknown:
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return "unknown"
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case VersionTLS:
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return "TLS dev version (WIP)"
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default:
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if vn > gquicVersion0 && vn <= maxGquicVersion {
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return fmt.Sprintf("gQUIC %d", vn.toGQUICVersion())
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}
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return fmt.Sprintf("%d", vn)
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}
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}
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// ToAltSvc returns the representation of the version for the H2 Alt-Svc parameters
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func (vn VersionNumber) ToAltSvc() string {
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if vn > gquicVersion0 && vn <= maxGquicVersion {
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return fmt.Sprintf("%d", vn.toGQUICVersion())
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}
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return fmt.Sprintf("%d", vn)
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}
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func (vn VersionNumber) toGQUICVersion() int {
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return int(10*(vn-gquicVersion0)/0x100) + int(vn%0x10)
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}
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// IsSupportedVersion returns true if the server supports this version
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func IsSupportedVersion(supported []VersionNumber, v VersionNumber) bool {
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for _, t := range supported {
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if t == v {
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return true
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}
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}
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return false
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}
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// ChooseSupportedVersion finds the best version in the overlap of ours and theirs
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// ours is a slice of versions that we support, sorted by our preference (descending)
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// theirs is a slice of versions offered by the peer. The order does not matter
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// if no suitable version is found, it returns VersionUnsupported
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func ChooseSupportedVersion(ours, theirs []VersionNumber) VersionNumber {
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for _, ourVer := range ours {
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for _, theirVer := range theirs {
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if ourVer == theirVer {
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return ourVer
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}
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}
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}
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return VersionUnsupported
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}
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