yggdrasil-network/yggdrasil-go
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copy/paste old flowkey logic into a util function, add a struct of key and packet, make WriteNoCopy accept this instead of a slice

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Arceliar 2019-08-06 19:25:55 -05:00
parent 6cb0ed91ad
commit 790524bd1c
5 changed files with 105 additions and 52 deletions
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38
src/util/util.go
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@ -106,3 +106,41 @@ func DecodeCoordString(in string) (out []uint64) {
}
return out
}
// GetFlowLabel takes an IP packet as an argument and returns some information about the traffic flow.
// For IPv4 packets, this is derived from the source and destination protocol and port numbers.
// For IPv6 packets, this is derived from the FlowLabel field of the packet if this was set, otherwise it's handled like IPv4.
// The FlowKey is then used internally by Yggdrasil for congestion control.
func GetFlowKey(bs []byte) uint64 {
// 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 {
flowkey = uint64(bs[6])<<32 /* proto */ |
uint64(bs[40])<<24 | uint64(bs[41])<<16 /* sport */ |
uint64(bs[42])<<8 | uint64(bs[43]) /* dport */
}
}
}
return flowkey
}