Skip to content
This repository has been archived by the owner on May 11, 2022. It is now read-only.

parallelize dialbacks #20

Merged
merged 6 commits into from
Apr 4, 2019
Merged

parallelize dialbacks #20

Changes from all commits
Commits
Show all changes
6 commits
Select commit Hold shift + click to select a range
67d2dcb
parallelize dialbacks
vyzo Apr 1, 2019
88875a7
reset confidence when there is a public<->private transition
vyzo Apr 1, 2019
de44e81
use anonymous struct for collecting dialback results
vyzo Apr 2, 2019
8244eed
add comments for status flips dropping confidence to 0
vyzo Apr 2, 2019
f645f11
don't flip to status unknown on first faiulure, use the confidence level
vyzo Apr 2, 2019
2584eaf
defer wg.Done
vyzo Apr 3, 2019
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
108 changes: 71 additions & 37 deletions autonat.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -32,7 +32,7 @@ var (
AutoNATBootDelay = 15 * time.Second
AutoNATRetryInterval = 90 * time.Second
AutoNATRefreshInterval = 15 * time.Minute
AutoNATRequestTimeout = 60 * time.Second
AutoNATRequestTimeout = 30 * time.Second
)

// AutoNAT is the interface for ambient NAT autodiscovery
Expand Down Expand Up @@ -135,50 +135,84 @@ func (as *AmbientAutoNAT) autodetect() {
}

cli := NewAutoNATClient(as.host, as.getAddrs)
failures := 0

for _, pi := range peers {
ctx, cancel := context.WithTimeout(as.ctx, AutoNATRequestTimeout)
as.host.Peerstore().AddAddrs(pi.ID, pi.Addrs, pstore.TempAddrTTL)
a, err := cli.DialBack(ctx, pi.ID)
cancel()

switch {
case err == nil:
log.Debugf("NAT status is public; address through %s: %s", pi.ID.Pretty(), a.String())
as.mx.Lock()
as.addr = a
as.status = NATStatusPublic
as.confidence = 0
as.mx.Unlock()
return
ctx, cancel := context.WithTimeout(as.ctx, AutoNATRequestTimeout)
defer cancel()

var result struct {
sync.Mutex
private int
public int
pubaddr ma.Multiaddr
}

case IsDialError(err):
log.Debugf("dial error through %s: %s", pi.ID.Pretty(), err.Error())
failures++
if failures >= 3 || as.confidence >= 3 { // 3 times is enemy action
log.Debugf("NAT status is private")
as.mx.Lock()
as.status = NATStatusPrivate
as.confidence = 3
as.mx.Unlock()
return
}
probe := 3 - as.confidence
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Could do:

var probe int
if probe = 3 - as.confidence; probe > len(peers) {
    probe = len(peers)
} else if probe == 0 {
    probe = 1
}

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

sure, can do if you think it's cleaner this way.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

there is a problem with doing it this way: if peers = 0 and probe is also 0 (confidence = 3), then we'll have an out of bounds slice.
then again we can't possibly have no peers and confidence = 3, so it should be ok.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

but I'd rather not have to think about this when reading the code (apparent bug that is not)

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I think I'll keep the original code here, as it needs no comments.

if probe == 0 {
probe = 1
}
if probe > len(peers) {
probe = len(peers)
}

default:
log.Debugf("Error dialing through %s: %s", pi.ID.Pretty(), err.Error())
}
var wg sync.WaitGroup

for _, pi := range peers[:probe] {
wg.Add(1)
go func(pi pstore.PeerInfo) {
defer wg.Done()

as.host.Peerstore().AddAddrs(pi.ID, pi.Addrs, pstore.TempAddrTTL)
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Note to self: using AddAddrs is ok here because if the peerstore has a longer TTL, it won't shorten in.

a, err := cli.DialBack(ctx, pi.ID)

switch {
case err == nil:
log.Debugf("Dialback through %s successful; public address is %s", pi.ID.Pretty(), a.String())
result.Lock()
result.public++
result.pubaddr = a
result.Unlock()

case IsDialError(err):
log.Debugf("Dialback through %s failed", pi.ID.Pretty())
result.Lock()
result.private++
result.Unlock()

default:
log.Debugf("Dialback error through %s: %s", pi.ID.Pretty(), err)
}
}(pi)
}

wg.Wait()
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Do we need to wait for all of them? That is, could we like, try N and wait for M?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

How would this work?

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Ask N nodes for dial backs but walk away after M responses. It may not be worth it but it would allow us to tolerate a few bad nodes.

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Note: I'm find merging this as-is.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I don't think it adds much to wait for fewer nodes, other than adding complexity. At worst a bad node will timeout, which is 30s.


as.mx.Lock()
if failures > 0 {
as.status = NATStatusPrivate
as.confidence++
if result.public > 0 {
log.Debugf("NAT status is public")
if as.status == NATStatusPrivate {
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

A comment here saying that we're flipping our asserted NAT status?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

A log comment I take it. Sure, will do.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

done

// we are flipping our NATStatus, so confidence drops to 0
as.confidence = 0
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Nit: Shouldn't this be a confidence of 1?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I prefer this to have a confidence of 0 if there is a flip, so that we get more observations in the next round.

} else if as.confidence < 3 {
as.confidence++
}
as.status = NATStatusPublic
as.addr = result.pubaddr
} else if result.private > 0 {
log.Debugf("NAT status is private")
if as.status == NATStatusPublic {
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Same comment as above?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

ditto

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

done

// we are flipping our NATStatus, so confidence drops to 0
as.confidence = 0
} else if as.confidence < 3 {
as.confidence++
}
as.status = NATStatusPrivate
as.addr = nil
} else if as.confidence > 0 {
// don't just flip to unknown, reduce confidence first
as.confidence--
} else {
as.status = NATStatusUnknown
as.confidence = 0
log.Debugf("NAT status is unknown")
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Is it ok for a single round with unresponsive peers to reset our NAT status entirely? I think we need some error tolerance here.

Copy link
Member

@raulk raulk Apr 2, 2019 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'd decrement the confidence and retain our previous status, until confidence drops to zero and then we can switch to Unknown?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

ok, that's reasonable.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Done - won't flip to unknown if we have any confidence, but rather reduce the confidence and wait for the next round.
It will only become unknown again if the confidence drops to 0.

as.status = NATStatusUnknown
as.addr = nil
}
as.mx.Unlock()
}
Expand Down