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24 lines
731 B
Go
24 lines
731 B
Go
package checksum
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import (
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"golang.org/x/sys/cpu"
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gvisorchecksum "gvisor.dev/gvisor/pkg/tcpip/checksum"
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)
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//go:noescape
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func checksumAVX2(buf []byte, initial uint16) uint16
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var hasAVX2 = cpu.X86.HasAVX2
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// Checksum computes the RFC 1071 ones-complement sum of buf, seeded with
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// initial. It is a drop-in replacement for gvisor's checksum.Checksum that
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// dispatches to a hand-written AVX2 routine on amd64 CPUs that support it,
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// falling back to gvisor's pure-Go implementation otherwise. The result
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// matches gvisor's bit-for-bit for any buffer length and initial seed.
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func Checksum(buf []byte, initial uint16) uint16 {
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if hasAVX2 {
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return checksumAVX2(buf, initial)
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}
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return gvisorchecksum.Checksum(buf, initial)
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}
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