tailscale/net/packet/ip.go
David Anderson 55b1221db2 net/packet: support full IPv6 decoding.
The packet filter still rejects all IPv6, but decodes enough from v6
packets to do something smarter in a followup.

name              time/op
Decode/tcp4-8     28.8ns ± 2%
Decode/tcp6-8     20.6ns ± 1%
Decode/udp4-8     28.2ns ± 1%
Decode/udp6-8     20.0ns ± 6%
Decode/icmp4-8    21.7ns ± 2%
Decode/icmp6-8    14.1ns ± 2%
Decode/unknown-8  9.43ns ± 2%

Signed-off-by: David Anderson <danderson@tailscale.com>
2020-11-10 20:23:54 -08:00

54 lines
1.3 KiB
Go

// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package packet
// IPProto is an IP subprotocol as defined by the IANA protocol
// numbers list
// (https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml),
// or the special values Unknown or Fragment.
type IPProto uint8
const (
// Unknown represents an unknown or unsupported protocol; it's
// deliberately the zero value. Strictly speaking the zero
// value is IPv6 hop-by-hop extensions, but we don't support
// those, so this is still technically correct.
Unknown IPProto = 0x00
// Values from the IANA registry.
ICMPv4 IPProto = 0x01
IGMP IPProto = 0x02
ICMPv6 IPProto = 0x3a
TCP IPProto = 0x06
UDP IPProto = 0x11
// Fragment represents any non-first IP fragment, for which we
// don't have the sub-protocol header (and therefore can't
// figure out what the sub-protocol is).
//
// 0xFF is reserved in the IANA registry, so we steal it for
// internal use.
Fragment IPProto = 0xFF
)
func (p IPProto) String() string {
switch p {
case Fragment:
return "Frag"
case ICMPv4:
return "ICMPv4"
case IGMP:
return "IGMP"
case ICMPv6:
return "ICMPv6"
case UDP:
return "UDP"
case TCP:
return "TCP"
default:
return "Unknown"
}
}