forked from quic-go/quic-go
9db23eceed
For the client, the Versions option in the quic.Config encodes the first entry is the preferred version. If not set, this should default to the highest supported version.
63 lines
1.7 KiB
Go
63 lines
1.7 KiB
Go
package protocol
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// VersionNumber is a version number as int
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type VersionNumber int
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// The version numbers, making grepping easier
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const (
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Version35 VersionNumber = 35 + iota
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Version36
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Version37
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VersionWhatever = 0 // for when the version doesn't matter
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VersionUnsupported = -1
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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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Version37, Version36, Version35,
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}
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// VersionNumberToTag maps version numbers ('32') to tags ('Q032')
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func VersionNumberToTag(vn VersionNumber) uint32 {
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v := uint32(vn)
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return 'Q' + ((v/100%10)+'0')<<8 + ((v/10%10)+'0')<<16 + ((v%10)+'0')<<24
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}
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// VersionTagToNumber is built from VersionNumberToTag in init()
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func VersionTagToNumber(v uint32) VersionNumber {
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return VersionNumber(((v>>8)&0xff-'0')*100 + ((v>>16)&0xff-'0')*10 + ((v>>24)&0xff - '0'))
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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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// HighestSupportedVersion finds the highest version number that is both present in other and in SupportedVersions
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// the versions in other do not need to be ordered
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// it returns true and the version number, if there is one, otherwise false
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func HighestSupportedVersion(other []VersionNumber) (bool, VersionNumber) {
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var otherSupported []VersionNumber
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for _, ver := range other {
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if ver != VersionUnsupported {
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otherSupported = append(otherSupported, ver)
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}
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}
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for _, v := range SupportedVersions {
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for _, ver := range otherSupported {
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if ver == v {
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return true, ver
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}
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}
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}
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return false, 0
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}
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