cwinfo/yggdrasil-go
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Merge pull request #315 from neilalexander/flowlabel

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Update switch flow separation for IPv4
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Neil Alexander 2019-01-21 23:22:40 +00:00 committed by GitHub
commit ad6ec6ab11
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1 changed files with 23 additions and 10 deletions
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33
src/yggdrasil/session.go
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@ -554,17 +554,30 @@ func (sinfo *sessionInfo) doSend(bs []byte) {
}
// code isn't multithreaded so appending to this is safe
coords := sinfo.coords
// Read IPv6 flowlabel field (20 bits).
// Assumes packet at least contains IPv6 header.
flowkey := uint64(bs[1]&0x0f)<<16 | uint64(bs[2])<<8 | uint64(bs[3])
// Check if the flowlabel was specified
if flowkey == 0 {
// Does the packet meet the minimum UDP packet size? (others are bigger)
if len(bs) >= 48 {
// Is the protocol TCP, UDP, SCTP?
// Work out the flowkey - this is used to determine which switch queue
// traffic will be pushed to in the event of congestion
var flowkey uint64
// Get the IP protocol version from the packet
switch bs[0] & 0xf0 {
case 0x40: // IPv4 packet
// Check the packet meets minimum UDP packet length
if len(bs) >= 24 {
// Is the protocol TCP, UDP or SCTP?
if bs[9] == 0x06 || bs[9] == 0x11 || bs[9] == 0x84 {
ihl := bs[0] & 0x0f * 4 // Header length
flowkey = uint64(bs[9])<<32 /* proto */ |
uint64(bs[ihl+0])<<24 | uint64(bs[ihl+1])<<16 /* sport */ |
uint64(bs[ihl+2])<<8 | uint64(bs[ihl+3]) /* dport */
}
}
case 0x60: // IPv6 packet
// Check if the flowlabel was specified in the packet header
flowkey = uint64(bs[1]&0x0f)<<16 | uint64(bs[2])<<8 | uint64(bs[3])
// If the flowlabel isn't present, make protokey from proto | sport | dport
// if the packet meets minimum UDP packet length
if flowkey == 0 && len(bs) >= 48 {
// Is the protocol TCP, UDP or SCTP?
if bs[6] == 0x06 || bs[6] == 0x11 || bs[6] == 0x84 {
// if flowlabel was unspecified (0), try to use known protocols' ports
// protokey: proto | sport | dport
flowkey = uint64(bs[6])<<32 /* proto */ |
uint64(bs[40])<<24 | uint64(bs[41])<<16 /* sport */ |
uint64(bs[42])<<8 | uint64(bs[43]) /* dport */