cwinfo/yggdrasil-go
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Simplify flowkey stuff further.

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cathugger 2018-07-30 02:15:57 +00:00
parent 36dcab9300
commit 68a482ed92
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1 changed files with 16 additions and 16 deletions
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32
src/yggdrasil/session.go
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@ -426,30 +426,30 @@ func (sinfo *sessionInfo) doSend(bs []byte) {
return
} // To prevent using empty session keys
var coords []byte
// Read IPv6 flowlabel field (20 bits).
// Assumes packet at least contains IPv6 header.
flowlabel := uint(bs[1]&0x0f)<<16 | uint(bs[2])<<8 | uint(bs[3])
if flowlabel != 0 {
flowkey := uint64(bs[1]&0x0f)<<16 | uint64(bs[2])<<8 | uint64(bs[3])
if flowkey == 0 /* not specified */ &&
len(bs) >= 48 /* min UDP len, others are bigger */ &&
(bs[6] == 0x06 || bs[6] == 0x11 || bs[6] == 0x84) /* TCP UDP SCTP */ {
// 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 */
}
var coords []byte
if flowkey != 0 {
// Now we append something to the coords
// Specifically, we append a 0, and then arbitrary data
// The 0 ensures that the destination node switch forwards to the self peer (router)
// The rest is ignored, but it's still part as the coords, so it affects switch queues
// This helps separate traffic streams (coords, flowlabel) to be queued independently
coords = append(coords, sinfo.coords...) // Start with the real coords
coords = append(coords, 0) // Then target the local switchport
coords = wire_put_uint64(uint64(flowlabel), coords) // Then variable-length encoded flowlabel
} else if len(bs) >= 48 /* min UDP len, others are bigger */ &&
(bs[6] == 0x06 || bs[6] == 0x11 || bs[6] == 0x84) /* TCP UDP SCTP */ {
// if flowlabel was unspecified (0), try to use known protocols' ports
// protokey: proto | sport | dport
pkey := uint64(bs[6])<<32 /* proto */ |
uint64(bs[40])<<24 | uint64(bs[41])<<16 /* sport */ |
uint64(bs[42])<<8 | uint64(bs[43]) /* dport */
coords = append(coords, sinfo.coords...) // Start with the real coords
coords = append(coords, 0) // Then target the local switchport
coords = wire_put_uint64(pkey, coords) // Then variable-length encoded protokey
// TODO could we avoid allocations there and put this work into wire_trafficPacket.encode()?
coords = append(coords, sinfo.coords...) // Start with the real coords
coords = append(coords, 0) // Then target the local switchport
coords = wire_put_uint64(flowkey, coords) // Then variable-length encoded flowkey
} else {
// flowlabel was unspecified (0) and protocol unrecognised.
// To save bytes, we're not including it, therefore we won't need self-port override either.