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net/packet: represent IP6 as two uint64s.

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For the operations we perform on these types (mostly net6.Contains),
this encoding is much faster.

Part of #19.

name                   old time/op    new time/op    delta
Filter/icmp4-8           27.5ns ± 1%    28.0ns ± 2%   +1.89%  (p=0.016 n=5+5)
Filter/tcp4_syn_in-8     38.8ns ± 2%    38.3ns ± 1%   -1.24%  (p=0.024 n=5+5)
Filter/tcp4_syn_out-8    27.6ns ±12%    24.6ns ± 1%     ~     (p=0.063 n=5+5)
Filter/udp4_in-8         71.5ns ± 5%    65.9ns ± 1%   -7.94%  (p=0.008 n=5+5)
Filter/udp4_out-8         132ns ±13%     119ns ± 1%  -10.29%  (p=0.008 n=5+5)
Filter/icmp6-8            169ns ±10%      54ns ± 1%  -68.35%  (p=0.008 n=5+5)
Filter/tcp6_syn_in-8      149ns ± 6%      43ns ± 1%  -71.11%  (p=0.008 n=5+5)
Filter/tcp6_syn_out-8    37.7ns ± 4%    24.3ns ± 3%  -35.51%  (p=0.008 n=5+5)
Filter/udp6_in-8          179ns ± 5%     103ns ± 1%  -42.75%  (p=0.008 n=5+5)
Filter/udp6_out-8         156ns ± 3%     191ns ± 1%  +22.54%  (p=0.008 n=5+5)

Signed-off-by: David Anderson <danderson@tailscale.com>
This commit is contained in:
David Anderson
2020-11-12 02:56:15 -08:00
parent 04ff3c91ee
commit 2d604b3791
3 changed files with 42 additions and 32 deletions
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28
net/packet/ip6.go
View File

@@ -12,19 +12,25 @@ import (
)
// IP6 is an IPv6 address.
type IP6 [16]byte // TODO: maybe 2x uint64 would be faster for the type of ops we do?
type IP6 struct {
Hi, Lo uint64
}
// IP6FromNetaddr converts a netaddr.IP to an IP6. Panics if !ip.Is6.
func IP6FromNetaddr(ip netaddr.IP) IP6 {
if !ip.Is6() {
panic(fmt.Sprintf("IP6FromNetaddr called with non-v6 addr %q", ip))
}
return IP6(ip.As16())
b := ip.As16()
return IP6{binary.BigEndian.Uint64(b[:8]), binary.BigEndian.Uint64(b[8:])}
}
// Netaddr converts ip to a netaddr.IP.
func (ip IP6) Netaddr() netaddr.IP {
return netaddr.IPFrom16(ip)
var b [16]byte
binary.BigEndian.PutUint64(b[:8], ip.Hi)
binary.BigEndian.PutUint64(b[8:], ip.Lo)
return netaddr.IPFrom16(b)
}
func (ip IP6) String() string {
@@ -32,11 +38,11 @@ func (ip IP6) String() string {
}
func (ip IP6) IsMulticast() bool {
return ip[0] == 0xFF
return (ip.Hi >> 56) == 0xFF
}
func (ip IP6) IsLinkLocalUnicast() bool {
return ip[0] == 0xFE && ip[1] == 0x80
return (ip.Hi >> 48) == 0xFE80
}
// ip6HeaderLength is the length of an IPv6 header with no IP options.
@@ -69,8 +75,10 @@ func (h IP6Header) Marshal(buf []byte) error {
binary.BigEndian.PutUint16(buf[4:6], uint16(len(buf)-ip6HeaderLength)) // Total length
buf[6] = uint8(h.IPProto) // Inner protocol
buf[7] = 64 // TTL
copy(buf[8:24], h.SrcIP[:])
copy(buf[24:40], h.DstIP[:])
binary.BigEndian.PutUint64(buf[8:16], h.SrcIP.Hi)
binary.BigEndian.PutUint64(buf[16:24], h.SrcIP.Lo)
binary.BigEndian.PutUint64(buf[24:32], h.DstIP.Hi)
binary.BigEndian.PutUint64(buf[32:40], h.DstIP.Lo)
return nil
}
@@ -92,8 +100,10 @@ func (h IP6Header) marshalPseudo(buf []byte) error {
return errLargePacket
}
copy(buf[:16], h.SrcIP[:])
copy(buf[16:32], h.DstIP[:])
binary.BigEndian.PutUint64(buf[:8], h.SrcIP.Hi)
binary.BigEndian.PutUint64(buf[8:16], h.SrcIP.Lo)
binary.BigEndian.PutUint64(buf[16:24], h.DstIP.Hi)
binary.BigEndian.PutUint64(buf[24:32], h.DstIP.Lo)
binary.BigEndian.PutUint32(buf[32:36], uint32(len(buf)-h.Len()))
buf[36] = 0
buf[37] = 0

6
net/packet/packet.go
View File

@@ -248,8 +248,10 @@ func (q *Parsed) decode6(b []byte) {
return
}
copy(q.SrcIP6[:], b[8:24])
copy(q.DstIP6[:], b[24:40])
q.SrcIP6.Hi = binary.BigEndian.Uint64(b[8:16])
q.SrcIP6.Lo = binary.BigEndian.Uint64(b[16:24])
q.DstIP6.Hi = binary.BigEndian.Uint64(b[24:32])
q.DstIP6.Lo = binary.BigEndian.Uint64(b[32:40])
// We don't support any IPv6 extension headers. Don't try to
// be clever. Therefore, the IP subprotocol always starts at