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https://github.com/amnezia-vpn/amneziawg-go.git
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75d6c67a67
Use parallel summation with native byte order per RFC 1071. add-with-carry operation is used to add 4 words per operation. Byteswap is performed before and after checksumming for compatibility with old `checksumNoFold()`. With this we get a 30-80% speedup in `checksum()` depending on packet sizes. Add unit tests with comparison to a per-word implementation. **Intel(R) Xeon(R) Silver 4210R CPU @ 2.40GHz** | Size | OldTime | NewTime | Speedup | |------|---------|---------|----------| | 64 | 12.64 | 9.183 | 1.376456 | | 128 | 18.52 | 12.72 | 1.455975 | | 256 | 31.01 | 18.13 | 1.710425 | | 512 | 54.46 | 29.03 | 1.87599 | | 1024 | 102 | 52.2 | 1.954023 | | 1500 | 146.8 | 81.36 | 1.804326 | | 2048 | 196.9 | 102.5 | 1.920976 | | 4096 | 389.8 | 200.8 | 1.941235 | | 8192 | 767.3 | 413.3 | 1.856521 | | 9000 | 851.7 | 448.8 | 1.897727 | | 9001 | 854.8 | 451.9 | 1.891569 | **AMD EPYC 7352 24-Core Processor** | Size | OldTime | NewTime | Speedup | |------|---------|---------|----------| | 64 | 9.159 | 6.949 | 1.318031 | | 128 | 13.59 | 10.59 | 1.283286 | | 256 | 22.37 | 14.91 | 1.500335 | | 512 | 41.42 | 24.22 | 1.710157 | | 1024 | 81.59 | 45.05 | 1.811099 | | 1500 | 120.4 | 68.35 | 1.761522 | | 2048 | 162.8 | 90.14 | 1.806079 | | 4096 | 321.4 | 180.3 | 1.782585 | | 8192 | 650.4 | 360.8 | 1.802661 | | 9000 | 706.3 | 398.1 | 1.774177 | | 9001 | 712.4 | 398.2 | 1.789051 | Signed-off-by: Tu Dinh Ngoc <dinhngoc.tu@irit.fr> [Jason: simplified and cleaned up unit tests] Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
102 lines
3.7 KiB
Go
102 lines
3.7 KiB
Go
package tun
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import (
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"encoding/binary"
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"math/bits"
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)
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// TODO: Explore SIMD and/or other assembly optimizations.
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func checksumNoFold(b []byte, initial uint64) uint64 {
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tmp := make([]byte, 8)
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binary.NativeEndian.PutUint64(tmp, initial)
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ac := binary.BigEndian.Uint64(tmp)
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var carry uint64
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for len(b) >= 128 {
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[:8]), 0)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[8:16]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[16:24]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[24:32]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[32:40]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[40:48]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[48:56]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[56:64]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[64:72]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[72:80]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[80:88]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[88:96]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[96:104]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[104:112]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[112:120]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[120:128]), carry)
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ac += carry
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b = b[128:]
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}
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if len(b) >= 64 {
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[:8]), 0)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[8:16]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[16:24]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[24:32]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[32:40]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[40:48]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[48:56]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[56:64]), carry)
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ac += carry
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b = b[64:]
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}
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if len(b) >= 32 {
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[:8]), 0)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[8:16]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[16:24]), carry)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[24:32]), carry)
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ac += carry
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b = b[32:]
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}
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if len(b) >= 16 {
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[:8]), 0)
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[8:16]), carry)
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ac += carry
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b = b[16:]
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}
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if len(b) >= 8 {
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ac, carry = bits.Add64(ac, binary.NativeEndian.Uint64(b[:8]), 0)
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ac += carry
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b = b[8:]
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}
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if len(b) >= 4 {
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ac, carry = bits.Add64(ac, uint64(binary.NativeEndian.Uint32(b[:4])), 0)
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ac += carry
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b = b[4:]
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}
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if len(b) >= 2 {
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ac, carry = bits.Add64(ac, uint64(binary.NativeEndian.Uint16(b[:2])), 0)
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ac += carry
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b = b[2:]
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}
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if len(b) == 1 {
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tmp := binary.NativeEndian.Uint16([]byte{b[0], 0})
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ac, carry = bits.Add64(ac, uint64(tmp), 0)
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ac += carry
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}
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binary.NativeEndian.PutUint64(tmp, ac)
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return binary.BigEndian.Uint64(tmp)
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}
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func checksum(b []byte, initial uint64) uint16 {
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ac := checksumNoFold(b, initial)
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ac = (ac >> 16) + (ac & 0xffff)
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ac = (ac >> 16) + (ac & 0xffff)
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ac = (ac >> 16) + (ac & 0xffff)
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ac = (ac >> 16) + (ac & 0xffff)
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return uint16(ac)
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}
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func pseudoHeaderChecksumNoFold(protocol uint8, srcAddr, dstAddr []byte, totalLen uint16) uint64 {
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sum := checksumNoFold(srcAddr, 0)
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sum = checksumNoFold(dstAddr, sum)
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sum = checksumNoFold([]byte{0, protocol}, sum)
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tmp := make([]byte, 2)
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binary.BigEndian.PutUint16(tmp, totalLen)
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return checksumNoFold(tmp, sum)
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}
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