mirror of
https://github.com/qdm12/gluetun.git
synced 2026-05-07 04:20:12 +02:00
Quentin McGaw
be92aa2ac4
- Existing option `WIREGUARD_MTU` , if set, disables PMTUD and is used - New option `PMTUD_ICMP_ADDRESSES=1.1.1.1,8.8.8.8` and `PMTUD_TCP_ADDRESSES=1.1.1.1:443,8.8.8.8:443` - ICMP PMTUD now targets external-by-default IP addresses - New TCP PMTUD (binary search only) as a second MTU confirmation and fallback mechanism. - Force set TCP MSS to MTU - IP header - TCP base header - "magic 20 bytes" 🎆 - Fix #3108
31 lines
839 B
Go
31 lines
839 B
Go
//go:build !darwin
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package tcp
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import (
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"github.com/qdm12/gluetun/internal/pmtud/constants"
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)
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func stripIPv4Header(reply []byte) (result []byte, ok bool) {
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if len(reply) < int(constants.IPv4HeaderLength) {
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return nil, false // not an IPv4 packet
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}
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version := reply[0] >> 4 //nolint:mnd
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const ipv4Version = 4
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if version != ipv4Version {
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return nil, false
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}
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// For IPv4 we need to skip the IP header, which is at least
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// 20B and can be up to 60B.
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// The Internet Header Length is the lower 4 bits of the first byte and
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// represents the number of 32-bit words of the header length.
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const ihlMask byte = 0x0F
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const bytesInWord = 4
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headerLength := int((reply[0] & ihlMask)) * bytesInWord
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if len(reply) < headerLength {
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return nil, false // not enough data for full IPv4 header
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}
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return reply[headerLength:], true
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}
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