net/dns: retry forwarder requests over TCP

We weren't correctly retrying truncated requests to an upstream DNS
server with TCP. Instead, we'd return a truncated request to the user,
even if the user was querying us over TCP and thus able to handle a
large response.

Also, add an envknob and controlknob to allow users/us to disable this
behaviour if it turns out to be buggy ( DNS ).

Updates #9264

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: Ifb04b563839a9614c0ba03e9c564e8924c1a2bfd
This commit is contained in:
Andrew Dunham
2023-09-07 16:27:50 -04:00
parent 098d110746
commit 530aaa52f1
13 changed files with 448 additions and 49 deletions
+1 -1
View File
@@ -304,7 +304,7 @@ func NewUserspaceEngine(logf logger.Logf, conf Config) (_ Engine, reterr error)
tunName, _ := conf.Tun.Name()
conf.Dialer.SetTUNName(tunName)
conf.Dialer.SetNetMon(e.netMon)
e.dns = dns.NewManager(logf, conf.DNS, e.netMon, conf.Dialer, fwdDNSLinkSelector{e, tunName})
e.dns = dns.NewManager(logf, conf.DNS, e.netMon, conf.Dialer, fwdDNSLinkSelector{e, tunName}, conf.ControlKnobs)
// TODO: there's probably a better place for this
sockstats.SetNetMon(e.netMon)