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control/controlclient, net/dnscache: use typed singleflight fork

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Change-Id: I12be4c5a91ae3a812fe88d9b2d15526fdbb5a921
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Brad Fitzpatrick
2022-06-17 10:09:23 -07:00
committed by Brad Fitzpatrick
parent 59ed846277
commit 13d0b8e6a4
4 changed files with 20 additions and 19 deletions
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20
net/dnscache/dnscache.go
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@ -19,9 +19,9 @@ import (
"sync"
"time"
"golang.org/x/sync/singleflight"
"inet.af/netaddr"
"tailscale.com/envknob"
"tailscale.com/util/singleflight"
)
var single = &Resolver{
@ -81,12 +81,18 @@ type Resolver struct {
// It is required when SingleHostStaticResult is present.
SingleHost string
sf singleflight.Group
sf singleflight.Group[string, ipRes]
mu sync.Mutex
ipCache map[string]ipCacheEntry
}
// ipRes is the type used by the Resolver.sf singleflight group.
type ipRes struct {
ip, ip6 net.IP
allIPs []net.IPAddr
}
type ipCacheEntry struct {
ip net.IP // either v4 or v6
ip6 net.IP // nil if no v4 or no v6
@ -150,14 +156,10 @@ func (r *Resolver) LookupIP(ctx context.Context, host string) (ip, v6 net.IP, al
return ip, ip6, allIPs, nil
}
type ipRes struct {
ip, ip6 net.IP
allIPs []net.IPAddr
}
ch := r.sf.DoChan(host, func() (any, error) {
ch := r.sf.DoChan(host, func() (ret ipRes, _ error) {
ip, ip6, allIPs, err := r.lookupIP(host)
if err != nil {
return nil, err
return ret, err
}
return ipRes{ip, ip6, allIPs}, nil
})
@ -177,7 +179,7 @@ func (r *Resolver) LookupIP(ctx context.Context, host string) (ip, v6 net.IP, al
}
return nil, nil, nil, res.Err
}
r := res.Val.(ipRes)
r := res.Val
return r.ip, r.ip6, r.allIPs, nil
case <-ctx.Done():
if debug {